#PID Control System

[silvercitysuperstore]

[messungauto]

Optimising Continuous Furnace Processes with Xpress PLC: A Smarter Way to Achieve Industrial Precision

In today’s high-performance manufacturing landscape, continuous furnaces play a critical role in delivering consistent, reliable, and high-throughput thermal processing. These systems are essential for industries where precision and control are non-negotiable.

At the core of these furnaces lies a sophisticated control system—Programmable Logic Controllers (PLCs). Among the most advanced is the NX-ERA Xpress: a compact, rugged, and modular industrial PLC engineered specifically for demanding real-world applications. Designed for durability and intelligence, it brings smart automation to environments where traditional systems fall short.

For more information about NX-ERA Xpress plc visit us https://www.messungautomation.co.in/products/plc/

[balaji-switchgears]

PID Control with PLCs: Implementing Closed-Loop Control Systems

In the rapidly evolving landscape of industrial automation, the ability to maintain precise control over processes is paramount. This is where PID (Proportional-Integral-Derivative) control integrated with PLCs (Programmable Logic Controllers) comes into play. PID controllers, when used with PLCs, form the backbone of many closed-loop control systems, ensuring stability, efficiency, and accuracy in various industrial applications.

At Balaji Switchgears, we specialize in delivering cutting-edge solutions that leverage the power of PLCs to optimize industrial operations. Let’s delve into how PID control works, its benefits, and its implementation in PLC industrial automation systems.

What is PID Control?

PID control is a widely used feedback mechanism in control systems that calculates the error between a desired setpoint and the actual process variable. This calculation allows adjustments to bring the process variable closer to the desired setpoint. PID control consists of three components:

Proportional (P): Addresses the present error.

Integral (I): Accounts for past errors to eliminate residual discrepancies.

Derivative (D): Predicts future errors based on the rate of change.

The combination of these three terms ensures that the system achieves optimal performance with minimal oscillation and steady-state error.

Why Use PLCs for PID Control in Industrial Automation?

PLCs are the heart of industrial automation, offering flexibility, reliability, and ease of integration. Integrating PID control within PLCs amplifies their effectiveness, allowing industries to achieve precise control over their processes.

Here’s why PLC-based PID control is preferred:

Scalability: PLCs can handle multiple PID loops, making them suitable for complex systems.

Customization: Advanced programming capabilities allow tailored control strategies.

Real-Time Processing: PLCs ensure immediate adjustments, reducing downtime.

Integration: Seamlessly works with other automation components like sensors and actuators.

Applications of PID Control in Industrial Automation

PID control with PLCs is utilized across a broad spectrum of industries:

Manufacturing: Maintaining optimal temperatures, pressures, or speeds in production lines.

Process Industries: Regulating flow rates, liquid levels, or chemical concentrations.

HVAC Systems: Ensuring consistent indoor climates in large facilities.

Energy Management: Controlling generators, turbines, and renewable energy systems.

At Balaji Switchgears, we supply state-of-the-art PLCs and components designed to implement robust PID control systems for these applications and more. read more......

[labotronicsscientific]

Microwave Synthesizer

Labotronics microwave synthesizer is a single mode microwave PID controlled unit equipped with intelligent integrated software systems.It process up to 64 samples of 30ml simultaneously in a stable microwave field.It measures temperature with infrared sensors and with an advance system it can monitors or control the pressure inside the reaction vessel without physical touch and it can also quickly cool down itself.It offer additional attachment of glass cooler when need to add more liquid during experiment and inserting of fiber optic sensor .It Display the real-time graph and data of working.

for more visit labotronics.com

[creativeelectricals]

Optimize temperature control for versatile cooling and heating system. Explore temperature controllers, including PID controllers for efficient in control systems.

[whirligig-girl]

Reference sheet for Eaurp Guz for ArtFight 2025.

More about Guz: -Tumblr Tag -Guzcomic: AO3 / Tumblr -Surviving Schwil AO3 / Tumblr

STARFLEET COMMAND PERSONNEL DATABASE ACCESS Name: "Eaurp Guz" Full Legal Name: Eaurp Eugigathlia Waralslaupwormn't Guz Date of Birth: Stardate 33013 (2356-January-06 A.D.) Place of Birth: Twin Slime Hall, Southern Gurfluint, United Mellanus, Zwo-Nmu System, Zalda Sector, Alpha Quadrant. Species: Mellanoid Slime Worm Age: 26 Earth Years Height: variable, roughly 1.4 meters. Rank: Lieutenant Junior Grade Division: Operations (Engineering Subdivision) Academy Class: 2379 Assignment: U.S.S. Cerritos NCC-75567 (2380-2382(present)) Previous Assignments: Douglas Station (2379-2380) Honorifics: Lieutenant, Miss, Ma'am. Pronouns (Federation Standard Language): She/Her/Hers/Herself. Sex: N/A. Gender: Woman, Xenogender, Transgender, Female, Girl Parents: Mx. Waral Slaup, Mx. Eurgus Fleud, Dr. "Worm" Zugui   (Bio below the cut)

Bio: Eaurp Guz grew up in the turbulent time immediately following first contact with the United Federation of Planets, during a time when much of the world of Mellanus was struggling to adapt to a new political situation. Her world had united under a single umbrella, and one of the unifying principles was that of a desire to do space exploration on Mellanus' own terms. Guz had always loved machines, and made a hobby out of robotics, model railroading, and model rocketry.  Through the latter, she gained an aerospace scholarship and went to gooniversity at Flugoz, where she became an intern for the United Mellanus Space Program. At the end of the Dominion War, she pivoted, realizing that she would have better career prospects--and accomodations for her neurodivergence and gender--in the futuristic Starfleet than she would on her homeworld. After four years of academy, where she excelled at engineering topics but struggled with other aspects of the curriculum, she graduated as one of only a small handful of Mellanoid Slimes in Starfleet, and an even fewer number of fully trained officers.  After a year working at Douglas Station as part of their maintenance and repair crew, she fell in love with the Cerritos while assisting in its refit after its run-in with the Pakleds towards the end of 2380. During 2380 and early 2381, she served on Delta Shift, but in late 2381 she transitioned to Beta Shift. Due to her original training and upbringing, she is a sublight propulsion systems specialist, and spends most of her time tweaking the impulse engines and maneuvering thruster control system to keep them operating at ideal efficiency and smoothness.  In a report given by Lt. Cmdr. Andy Billups in late 2381, he noted "She is a skilled engineer, but she only seems to want to apply herself to this one specific subfield. She'll make an excellent specialist, but I am not considering a promotion at this time." END REPORT. APPENDIX TO PERSONNEL BIO Since the previous report, Eaurp Guz has been promoted to Lieutenant Junior Grade following a harrowing experience on planet TE-92f, in which she demonstrated a high degree of technical mastery over a wide variety of engineering domains. She has been transferred into an Command and Operations training track to ensure she is better equipped to get herself out of the situations she has proved to be able to get herself into, Starfleet Command having determined that she, quote, "slipped through the cracks, pun intended" of Starfleet Academy's career assignment program. Lt. Guz herself was hesitant to accept the promotion, claiming to prefer such tasks as crawling around in Jeffries Tubes, optimizing impulse engines, and tweaking maneuvering thruster PID controller values. Personal Section: Hobbies: Model rocketry, model starship engineering, railway modelling, holographic aerospace flight simulation, technical artist, amateur astronomy. Sexual orienation: asexual (or possibly demisexual, for a broad definition of 'sexual') Romantic orientation: polyamorous lesbian demiromantic Notable Friends: * Slamtha Uzgoel (Childhood friend, 2368-2376) * Dyani (Academy Roommate 2375-2379) * Marta Martinez (Academy classmate 2376-2379) * Eyluss Iris (Crewmate 2380-) * Lisdolin Kerman (Crewmate 2380-) * Samanthan Rutherford (Crewmate 2380-) * D'vana Tendi (Crewmate and Medical Provider 2380-) * T'lyn (Crewmate 2381-) * Zhandar Ghel (Stranded on Schwil Together 2381) * Doctor Promised Vision (Schwil, 2381) Enemies:  * Slamtha Uzgoel (Syndicate pirate with a grudge 2381-) Love Interests <3: * D'vana Tendi (Guz's crush 2381-2382, Guz's girlfriend following Tendi's return to the Cerritos 2382-) * Slamtha Uzgoel (childhood friends in a QPR 2368-2376, so into Guz it ruined her life 2376-) * Marta Martinez (had a crush on Guz 2375-2379) * Zhandar Ghel (survived a traumatic experience together 2381)

[anumberofhobbies]

Fearsome tremors at high speed At first glance, levitating a train above magnetic rails seems like a perfect way to escape the constraints of gravity. No contact, no friction, just near-perfect gliding. But in practice, even the tiniest imperfections can cause problems. Deformed bridges, slightly crooked coils, and the cab starts to vibrate at fearsome frequencies. Researchers at the Datong test site in Shanxi province dissected the problem in detail. They discovered that at speeds of 400 kph and above, the cab was subjected to vibrations that were deemed “extremely unpleasant”, reaching a Sperling index of 4.2 at 600 kph. This index, developed in the 1940s, measures passenger discomfort: at 4.2, the vibrations are so strong that they can be harmful to health on long journeys. AI at the service of cushioning The remedy found by these same researchers consists of a hybrid suspension system that combines conventional air springs and electromagnetic actuators. The real innovation here is the on-board AI. Using a “sky-hook” strategy, the algorithm simulates an anchoring point to counter low-frequency jolts. The second technique uses a PID controller: a barbaric acronym for Proportional, Integral and Derivative. In short, the AI constantly adjusts the forces to correct the capsule’s trajectory. To fine-tune the settings, the engineers turned to a NSGA-II genetic algorithm, a bit like a gene selector looking for the most effective combination to keep the capsule stable. Promising tests The results speak for themselves. On a scale model, vertical vibration fell by 45.6%. The Sperling index fell below 2.5, a sign that comfort is now judged to be “pronounced but not unpleasant”. A clear improvement, even at 1,000 km/h.

[pteroducktyll]

FtM Hysto Recovery + Tips (Plus general tips for dealing with low/no spoons or recovering from any surgery)

I haven't been on Tumblr for years, but recently re-joined to check out art, as I start to work on getting my idea for a graphic novel off the ground (as well as getting serious about improving my art again). However, I'm hoping these first few posts get found by an entirely different audience. This is being written in 2023.

I'm going in for a laparoscopic hysterectomy on Thursday (today is Monday) and want to share my experience, as much as spoons will allow, so that other people can hopefully benefit in the future. I, personally, have struggled to find things online that fit my situation as a trans man with a history of pre-cancerous pap smears, abnormal bleeding, PID and ovarian cysts (but not PCOS). Although hysterectomies for "GRS" or gender affirming surgery purposes are easy to get where I live, mine in particular is primarily being done to avoid cancer and to stop the abnormal bleeding and random debilitating pain that comes out of nowhere every few years and upends my life for weeks/months. So if you're someone facing the prospect of a laparoscopic hysterectomy, regardless of your gender identity, and have a history of medical issues (but not PCOS or endometriosis) in your reproductive region, this blog may help you! Or, alternatively, if you're a trans man looking to get a laparoscopic hysterectomy, whether or not you've had issues in that region, this might help you, too!

It should be noted that this is written from the perspective of someone in their 30s with a complicated medical history, including Type 2 Diabetes and a very rare kidney disease (which has an average life expectancy of 29 years for men, but we aren't sure how it affects trans men), so the pre-surgery process I've been through is not the typical one. I also have chronic pain and know from my past experiences with very severe pain that a) I have a low tolerance for any pain beyond what I deal with day-to-day and b) I have a high tolerance for opiate pain medication, which means it takes a higher dose for me to address the level of pain that a lower dose would address in someone else. These both affect the length of time that I'll likely need to be on painkillers, and how functional I'll be while I'm on them. This, in turn, affects how quickly I'll be able to do things like return to work and driving.

I should also note that although it's common in some places for this surgery to be completed as day surgery, my jurisdiction almost always keeps people in overnight; this is because it takes almost 24 hours for the anesthetic to work its way out of your system, and until it does they won't have a true indication of your pain levels and, therefore, won't be able to make sure it's adequately controlled before sending you home. It's much easier (in my experience, and according to the doctors!) to stop you from having pain in the first place than to get it under control once you do.

Also, I live with my partner and a roommate, and my retired parents are about 90 minutes away and have a guest room. My support network isn't huge, but it's high quality. My partner managed to get 3 days off work for my surgery and the 2 days following, and after that is on a light workload for about a week in case she needs to take care of me. She also has a lot of flexibility with her job, and her boss really likes me, so if there are complications or she needs to spend more time at home to look after me, I don't think it's completely out of the question. All of this is to say that I'm going into this surgery from a very privileged place, in terms of not having to do much to look after myself in the aftermath. My surgeon did advise me, however, to take 1 week (for sure) off work if I could, and that I may need a second week. My work consists of two research jobs that draw heavily on my brain power, but don't require me to move around at all, especially as I work from home, so the issue is the painkillers, rather than actual healing time. Other jobs will require different amounts of time off work.

Because I'm neurodivergent and like to have as many details as possible about ... literally everything, I'm going to make this as detailed as I can. Essentially, I'm hoping to share everything I know and experience without leaving anything out. If it's too much detail for you, I'm going to be doing my best to include useful headers.

Notification of Surgery & Lead-up

I received notice about my surgery just over a month before my surgery date; it was around June 26th that I was emailed and told my surgery would be on August 3rd. I had previously met my surgeon in January, and was told it would be a 6-8 month wait until surgery. Between that appointment and being given my surgery date, I'd had bloodwork done, as well as an internal ultrasound. I've had several internal ultrasounds before and while they are far from pleasant, they are not as dysphoria-inducing for me as they are for other trans men, I'm sure. I am more physically uncomfortable during them than mentally/spiritually uncomfortable.

In the notification email, my surgeon sent additional attachments; about 200 pages of information from a) their office specifically and b) the health authority [one document about hysterectomies, one document about recovering from surgery in general]. These documents answered most of my questions, and also had instructions about fasting, pre-surgery instructions (there's a special sponge I have to buy and use the night before surgery and the morning of surgery) and recovery information. The documents were very generic, and because they came from different sources, the information was sometimes contradictory. I, personally, took the information on board in this order of trustworthiness:

Things my surgeon had said in-person during my consultation appointment in January

Things included in the information from my surgeon's office directly

Things included in the documents from the health authority

If there were contradictions that seemed extremely important (e.g. one document said to wash everything my face with the special sponges, while another said, in all caps, to absolutely NOT wash my head or face with the sponges), I followed-up with the surgeon's office or the most appropriate person (e.g. pharmacist).

Pre-surgery Appointments

Because of my medical history (diabetes and Alport's Syndrome), I had an extra step in here. My surgeon required me to have a consultation with my internal medicine doctor's clinic (but not with my specialist) to get the all-clear and make sure my risk level wasn't too high. This doctor made some assumptions about the medications I'm taking, which led him to think I had both diabetes and a heart condition, which would have put me in a much higher risk category. Because of that, he ordered extra bloodwork, and an ECG, and booked a follow-up with me for a few days later. That initial appointment with him ended on the assumption that the surgery likely would be postponed. However, the bloodwork and ECG all came back fine, and at the follow-up he gave me the all-clear and said my risk wasn't very high at all.

I had a few other pre-surgery appointments.

One was with the surgeon. In my case, the doctor actually doing my surgery is a resident colleague of the surgeon I initially consulted with. Now that I had a specific date for the surgery, and my life situation had changed a bit since the consultation (e.g. work), I asked to meet with the surgeon to ask questions that had come up since the initial consultation, and so that I could meet the person who would be cutting into me and make sure I was comfortable with her. She answered all my questions really well, and it turned out I was more comfortable with her than the original surgeon. This was a quick 5-10 minute talk, but I highly recommend asking for it, even if your surgeon hasn't changed. You'll have another chance to talk to your surgery just before being wheeled into the OR, but you'll be nervous and may be medicated by then, and it's just nice to have this conversation ahead of time and in an environment where you can look at a list of questions you've written down, and actually pay attention to the answers.

The hospital required another two appointments before surgery:

The pharmacist

About a week before my surgery, the pharmacist called for 5-10 minutes to discuss my current medications, supplements, vitamins and holistic medicines (if I were taking any) and to find out what time of day I take them at. Easy peasy.

2. The anesthetist

Exactly a week before my surgery, the anesthetist called to discuss the operation itself and the anesthetic. I'm not sure if the doctor I talked to will be the anesthetist who is actually in the room with me, or if it was just her job that particular day to call and get the information that will get passed onto the one who will be in the room. She was very nice, and explained the method of anesthesia, as well as how I'll likely feel when I wake up, etc. She also saw on my chart that I have a history of chronic pain, and zeroed in on my back and shoulder. She asked if there are any positions that make me more comfortable, and then explained the position I'd be in for my surgery -- tipped back toward my head -- and that this sometimes gives people back and shoulder pain even if they don't have any to begin with. She said my arms would be alongside my body, fairly tight to it, and I said that would be fine. I practiced laying them beside my body later that day and promptly discovered that's actually pretty painful for one arm, but I'll mention that when I get there and hope for the best! If I was having the conversation again, I'd answer by saying I wasn't sure how that would feel but that I'd practice it before the surgery day to see, and then ask who I could talk to if it turned out there's a better position or if that one wouldn't work. Ultimately though, the surgery should be 1.5 hours to 4 hours at most, so I'm not overly concerned. What you should take away from this if you're having this surgery and don't already have back/shoulder pain is that you might wake up with some, but that it should go away in a day or maybe a little less. This type of surgery also requires the surgeon to inflate your belly with gas in order to make room for the scopes and so that they can see what they're doing. That gas can stick around for a day, sometimes two, according to the anesthetist and can be a little bit painful or uncomfortable. I can't remember anything else that came out of this conversation.

In terms of pre-surgery appointments, that was it.

Tips and Tricks for Being Prepared

The next little bit is information I acquired through talking to my therapist (who's had several laparoscopic surgeries!) and many hours of research online, as well as living as a person who often has few spoons.

Get your first 1-2 weeks of meals planned and ready in advance. For me, this means I've picked up a large number of cans of Alphaghetti-type foods, and I'll be buying as many frozen meals as I can but have VERY little freezer room because my partner and I share with our tenant. Other options include things like HelloFresh, identifying nights when it will be easier for your partner if you order food in (if you can afford to), making big batches of food leading up to surgery while you're well and then freezing them, creating a list of meals you'd appreciate friends bringing over [remind them to bring them in disposable containers, so you don't have to feel guilty when it takes you weeks to get the containers back to them!], etc

Buy some Depends/adult diapers. I bought store brand (Life brand, specifically, which is Canadian) ones. The only ones I could get were maximum absorbency unless I wanted to pay twice the price for name brand ones, but I suspect I could do with a minimum absorbency one. I bought the underwear-style ones. In the store brand, they don't look very underwear-like at all, but if you have more money to spend, some of the name brand ones look convincingly like underwear! I also bought 'Unisex' ones, but would have bought womens if the unisex ones weren't an option; I suspect the mens' might have a built-in bulge area that would be awkward for me. The point of the adult diapers is that their 'waistband' is not a traditional waistband -- it's about 8" tall, very thin, and crinkle-cut so that it doesn't put pressure on your skin. This will stop you from having clothing pushing on your incision sites. BONUS is that they ARE absorbent, so you won't have to also wear pads to deal with discharge (which can, apparently, last for 6 weeks). Try the Depends on for a day a few days before surgery. Yes, it will be awkward and you'll feel silly. I am literally sitting in bed, with nothing wrong with me, wearing nothing but an adult diaper and a tee shirt while my partner's at work. But this has 2 purposes: 1) chances are you haven't worn these before, and you want to make sure you've got the most comfortable ones you can in terms of fit and style; 2) if you've worn them once already, it'll be familiar when you go to put it on when you're ready to leave the hospital; you'll know which side is the back and which side is the front, and the 'weirdness' of wearing them will be less unsettling. You're going to have other weird stuff going on, this doesn't have to be yet another weird thing happening!

If you live alone or your partner doesn't (or can't) change the sheets, layer sheets on the bed. That's right, layer your mattress with bottom sheets. That way, you can peel the top one off and have a cleaner sheet beneath it. It won't be the same as being able to sleep on a fresh, clean sheet straight out of the cupboard or dryer, but it's going to be better than the one you've slept, sweat or, universe forbid, bled on.

Get a LEAKPROOF (truly) travel mug with a handle. After surgery you'll have maybe one comfortable position to lay in. You're not going to want to get out of that position to retrieve your water, but you're also going to need to be drinking a lot of water (it helps you recover, and also helps get your bowels moving again). Being able to lose your water in the bed is a luxury, but a necessary one. I got mine at Winners for pretty cheap.

Get a nightie or onesie. I usually sleep naked. I don't really own pyjamas -- when I need to cover up to sleep (like when I visit friends or travel), I throw on a pair of joggers, or boxer briefs. But those both have waistbands and, remember, we're trying to avoid waistbands. I ordered a sleep shirt from Oodie, which was on sale, but still expensive (I paid around $60, including 1-2 business day shipping because I didn't think of it until the last minute), as well as a halloween one-sie from Old Navy that's apparently leftover from last year's halloween stock. I'm expecting the onesie to be way too hot, but I need something I can wear out in public in case I have to get groceries, or pick something up at the pharmacy, or stand outside because the building's burning, without exposing myself. I also borrowed a robe to go over the sleep shirt when I leave the hospital.

Have whoever's picking you up bring 2 pillows. One goes between your abdomen and the seatbelt, and you sit on the other one.

Have whoever's picking you up bring fast food. When you leave the hospital you're going to either be ravenously hungry or feel like you never want to eat again. Either way, fast food is going to be the one thing you didn't realize you needed so badly in your life until that moment. Your body's going to be craving carbs and fat, and fat is also what's going to help your pain pills kick in.

Have ice cream, chips or other junk food on hand. This is mostly so that you have something to eat when you take your pain pills. Fatty foods help opiates work faster; as someone who takes them several times a month for chronic pain, I've sometimes noticed a difference of -hours- between taking them with fatty foods and taking them on their own.

Get a walking aid. We use our abdomens for everything. If you don't already have something like a cane, pick one up. Keep the receipt though; if you don't end up using it, you can usually take them back. With that said, my therapist said it's at about the 2 week mark when you feel like you actually need one. If you don't have a cane but you have walking/hiking sticks, dig them out and keep them handy.

Grab some baby wipes. You can get laparoscopic incisions wet, but that doesn't mean you're going to feel like you have the energy or endurance to shower right away. You're still going to want to keep your pits and bits clean.

If you take daily medications, organize them in a pill organizer. Things can get confusing when you're on painkillers, or when a partner is dishing out your meds. You know exactly how many you take, and how often, so the best way to approach this is to get a pill organizer and get all your doses for a week ready before your surgery. Monday AM, Monday PM, Tuesday AM, Tuesday PM, that kind of thing. There's nothing worse than being on painkillers and trying to remember if you've already taken That Very Important Medication You Can't Miss or not. Or, worse, not even realizing you've missed something that can give you withdrawal symptoms, and suddenly waking up a few days after surgery feeling worse than you've ever felt in your life and wondering if you need to go to the ER, only to have it turn out that you missed your meds.

Buy something for yourself that you can look forward to. I bought a video game that I've wanted for a couple of years that was finally on sale. I haven't touched it, and won't until sometime after surgery when I feel up to it. Giving yourself a little reward when you're going through something hard is always nice.

If you're diabetic...take a minute before your surgery to remind your partner/anyone you live with/anyone who's going to be looking after you about how and when to check your blood sugars, what numbers are abnormal for you, and what to do about them. Being ill or recovering from a surgery can really throw your diabetes out of whack, even if it's well-controlled beforehand, and recovering from surgery might make you feel a lot of the same symptoms you'd feel from a hypo/hyper or DKA, so make sure you (or someone else) test your sugars regularly and have things on hand to deal with abnormal or worrying results.

Take your phone everywhere. Painkillers (and pain) can make us unsteady. As someone who's taken a fall and had to wait hours for my partner to wake up and find me and help me back to my feet (and then bed), I don't recommend it.

These are the things I know about pre-surgery, but I'll try to update...eventually if I learn anything new post-surgery.

[viskarenvisla]

Where the Shadows Lie: Chapter 2 - Five Seconds of Eternal Spring

There was something about the chase - no, not the chase, the totally-not-creepy approach - that already felt romantic. She wandered back toward the reference stacks, where the shadows drew long and illumination bloomed from dim 1980s desk lamps. I felt like I was following her through a place that was at once an enchanted forest, but also the school library.

I meant it quite literally.

Vines and ivy twisted among the bookshelves, disappearing up into the ceiling, curled around glowing blue stones. I saw bizarre, long-limbed figures crawling amidst them, little dibbuks or something with oversized noses and pointed ears on unknowable missions. 

A…troll? Was it a troll? Something big and brutal-jawed with beady black eyes and sloped shoulders leans forward to pick through painting catalogues, mumbling unintelligibly to the crow-feathered girl scanning a QR code.

I ignored them, following the gentle percussion of Tessa’s shod hooves around another stack. I reached one of those towering walls of tomes the library curates but few people seem to stumble across. Their age could be measured in triple digits, and a slender iron ladder on wheels was required to reach up to the higher levels…how was that not a bold-faced defiance of OSHA?

Lanterns hung from the ceiling, limning her in pale light as she stood on one of those ladders a few meters above me. 

I was engrossed by the sight of her, and I will not pretend like I’m a man of decency…I dared an errant peek under her skirt and felt my breath hitch at the sight of that bright purple thong gracing her hips; I could see the swell of her sex pressed against the fabric, the shape of bulbous labia beneath. 

Quickly shifting my attention from between her thighs to something less obviously perverse, I cleared my throat to get her attention.

Grab the bull by the horns.

The garden of my woes overflowed with problems, spilling forth unattended into the orderly, if barren estate of my life. 

Lasciviously pink purslane danced in bands across the courtyard of my mind, as Tessa waltzed gracefully through my thoughts…I could practically taste her, right on the tip of my tongue.

A black bramble of fear spiderwebbed outward from mildew-ringed puddles of rainwater…my stalker’s blank visage stared up at me from the puddle…not a reflection, but somehow omnipresent in the water.

A tangled, dead oak tree that had once flowered proudly among the pillars of my identity mouldered and turned stony. Once colorful Khamdoan prayer flags were stamped with black bile that read ‘POSITION TERMINATED’.

As if those three blights weren’t bad enough, there loomed a fourth complexity in my life I’d yet to solve, one quite different from the other three. It was the Bascom Ridge Suspension Bridge problem; a conundrum that should not have kept me up as it did but it was just in the way; there was a poetic relevance to it.

Let me explain.

Professor Paz had randomly assigned a group project to the entire Control Systems class, and I ended up with Bohen Sautner and Milly Long; the former was singularly focused on his future career with the NBA (yeah good luck pal) and, due to his position on the college’s lucrative basketball team, he was generally allowed to coast by. Milly Long did her part of the project with a certain lackluster haste, so while it was done, I’d probably have to make sure it wasn’t garbage.

For my own part, I had to design a Proportional-Integral-Derivative (PID) controller; in common English, that’s a control device that responds to external change. In the case of the bridge, that means gusts of wind and the kinds of waves that we see in Dade County…Or that made traversing the different Abbacies perilous in Khamrungsa. 

Didn’t take a genius to see how that would have been useful for me.

There was always the temptation to give in to despair, cut my losses, drop out and go work in carpentry…but how soulless that felt. That in turn makes me feel entitled; if I hadn’t gotten lucky and had Rachel to help me get here, my choices would be scarce. 

My best friend Aryn, for instance, wasn’t so lucky; she was playing it safe with loans to go to the tech college and become a phlebotomist, just so she could have some income in this price gouge-singularity of a town.

Speaking of, my phone made a quiet blip as she pinged me; I was thankful for a distraction from Kp over Ki.

<blockquote> `Aryn: bruv are you still in the library designing a video game controller`</blockquote>

As was usually the case she found my plight amusing; she’d heard me whining about it, interspersed with my own equivocations concerning Tessa…should I make a move? Should I wait for her to make a move? Would she even make a move? ‘Why oh why did her pantherine form dance across the backs of my eyes as if seared there by a darkening flame?’ I would ask Aryn, prompting her to gag.

<blockquote>`Ascher: yes I am, it doesn’t have nearly enough buttons. whut do you want`

`Aryn: some of that kosher bussy, boi 🍆💍 ur gunna be ma strawberry 🍓`

`Ascher: 😐`

</blockquote>

Christ. I didn’t even know that word existed until she exposed me to it with her…eccentric taste in comics and pornography. I didn’t even know how she got a hold of that stuff, the university system was strict about checking our online activities.

I knew what she was bothering me for, of course…the four of us - me, Aryn, Karl and Vicky - had a YouTube channel with a few thousand subscribers, hardcore fans of our ‘ghost hunting’ show. I caught it all on camera when we went into abandoned factories, moldering houses and sealed-off university wings to catch paranormal activity. 

Some of it was even real.

<blockquote>`Ascher: bro i can’t come i know you’re going to ask me`

`Aryn: ascher can you not be a little bitch? We suck at this when you don’t come, karl’s pantaloons are still brown cuz of possum-poltergeist`

`Ascher: 👻🐭 is this just part of an elaborate plot to get me in your bed to lay some cable? All you gotta do is ask boo 👄`

`Aryn: 🤮 why did i ever show you that episode, now you’re laying cable everywhere man; in bed, in your car. dude come on it’s our season finale, we’ll stay up late and wait for your slowness`</blockquote>

It was a kind offer, but I intended to be here until midnight at least. I glanced at the corner of my laptop’s monitor…already half past 9. I had a long way to go and found myself chained to the seemingly impossible conundrum of the derivative term in my equation…again, in layman’s terms, I have to build a mechanism that moves the suspension cables of a bridge to compensate for the environment so it doesn’t collapse. 

The derivative was the part that predicts what will happen in the future, so the cables don’t overcompensate and snap like dental floss.

I was always a mediocre hand at math, and dealing with the added distortion of choppy wind, waves and simulated traffic gurgling over my bridge was making my life difficult. Differential calculus in particular was not my strong suit, even if Linear Algebra was. 

All of it was abstract as a color’s flavor.

I really didn’t want to disappoint them but I had to wonder…was this me being ‘incredibly weak’, or just caring about my friends’ safety and happiness?

<blockquote>`Ascher: if i finish by midnight ill tell you but don’t go without me, you’ll get possessed and it will get weird.`

`Aryn: what if the ghost is a hot chick? if you come back to my place it’ll be like you’re with two chicks at once, or if the ghost is a hot dude it’ll be awesome for me having two dudes inside me 🥵🌶️`</blockquote>

Ah. That was one of the reasons she wanted me to come out tonight. 

The exact texture of my friendship with Aryn was a complex tapestry that went back to when we were five years old in the same shitty foster care hovel. She and I have been through a lot together; I actually lost my v-card to her (she lost hers to that douchebag Kyle Burgmann with the Lamborghini) and…we definitely mess around when neither of us is seeing anyone. I’d recently broken up with Nieve Chen (a curious ache that lingered in spite of its bitter ending) and Aryn and I had already dallied a few times.

Sometimes I wondered why I didn’t just date her, and remembered it’d be…weird. 

Weirder than fucking her. I could use the relief and closeness, though.

<blockquote>`Ascher: if im done at midnight ill come with you guys and if im not i can still come over tonight and relieve you of your tension`

`Aryn: mmmm good 👅 I could use a nice deep massage, you get places most folks can’t`</blockquote>

Flattery always worked, frankly…I could already feel a stirring in my loins as I pictured joining Aryn in her bed, her dark thighs smooth and mostly exposed in the shorts she slept in. She had a voracious appetite to match mine; there was that at least. 

Still…she wasn’t the object of my desires. That person, in fact, was sitting three tables down, diligently working on her own project.

My thoughts drifted from Aryn like a flock of birds abandoning an electric pole, drawn toward the dawn…laying eyes upon her felt like the sun cresting over the stormy horizon of my heart. How could I describe someone like Tessa? Everytime I tried it felt inadequate. 

She’d strung little wildflowers on green tendrils amidst her horns; it made her appear as if drawn from a Bouguereau painting. The delicate lines of her face were relaxed, wearing a cupid’s bow smile as she bobbed her head to whatever was playing in her earbuds.

Tessa had been catching me staring more often, and when I felt the whiskey-warmth of her gaze track toward me I looked away lamely, pretending I was glancing at my phone…and when I dared sneak a peek back I made contact with her eyes. 

My breath caught, lips parting like I already had some excuse lined up.

She was wearing a lacy, low-cut black tank top that proudly displayed the ripe fullness of her bosom; I could see the impression of her nipple rings pressing against the fabric, infinitely tempting. A little necklace of pink and blue blossoms dangled around her shoulders, golden pinpricks of light rising from gently waving stamens. To my complete surprise Tessa smiled warmly at me, and - 

- in my mind I was suddenly transported to a tan prominence of rock overlooking an unknown sea The Gulf of Antalya. Her curled dark tresses whipped against my face as we stared into each other’s eyes. The heat was oppressive but dry, and her Aegean-tan skin was sheened with only a light gleam of perspiration. “Nothing in all Seleukeia, in Thrakesia or Dyrrachion can match your radiance,” I tell her -

…that didn’t feel like my usual imaginative meanderings. What was that…?

While I was staring blankly at my computer screen, I heard the rhythmic thnk-thnk-thnk-thnk of Tessa’s hooves, and when I looked up she was sashaying away toward the back of the library. A shimmery, almost weightless skirt of silver drifted around her toned legs; her shins sported short brown fur and ended in cloven hooves. 

She looked once more at me over her shoulder, as if to check that I was still staring. 

Which I was.

I thought about Doctor al-Rashi’s advice, to ‘seize the bull by the horns’ which had an uncomfortably suggestive air. Still…the underlying meaning was significant. 

That impulse you get when you’re about to do something really risky and crazy snuck up on me, you know? That sort of free-wind spirit that has your eyes blown wide open while you’re doing something insane like, jumping off a roof into a pool, or starting a fight you can’t win, or chasing a girl who was WAY out of your league.

I got up and followed her.

There was something about the chase - no, not the chase, the totally-not-creepy approach - that already felt romantic. She wandered back toward the reference stacks, where the shadows drew long and illumination bloomed from dim 1980s desk lamps. I felt like I was following her through a place that was at once an enchanted forest, but also the school library.

I meant it quite literally.

Vines and ivy twisted among the bookshelves, disappearing up into the ceiling, curled around glowing blue stones. I saw bizarre, long-limbed figures crawling amidst them, little dibbuks or something with oversized noses and pointed ears on unknowable missions. 

A…troll? Was it a troll? Something big and brutal-jawed with beady black eyes and sloped shoulders leans forward to pick through painting catalogues, mumbling unintelligibly to the crow-feathered girl scanning a QR code.

I ignored them, following the gentle percussion of Tessa’s shod hooves around another stack. I reached one of those towering walls of tomes the library curates but few people seem to stumble across. Their age could be measured in triple digits, and a slender iron ladder on wheels was required to reach up to the higher levels…how was that not a bold-faced defiance of OSHA?

Lanterns hung from the ceiling, limning her in pale light as she stood on one of those ladders a few meters above me. 

I was engrossed by the sight of her, and I will not pretend like I’m a man of decency…I dared an errant peek under her skirt and felt my breath hitch at the sight of that bright purple thong gracing her hips; I could see the swell of her sex pressed against the fabric, the shape of bulbous labia beneath. 

Quickly shifting my attention from between her thighs to something less obviously perverse, I cleared my throat to get her attention.

Grab the bull by the horns.

She favored me a glance downward.

“Hey Tessa. Hope I’m not…catching you at a bad time?” I hazarded; god that sounded lame.

To my surprise she smiled again and the sun blazed triumphant in my chest. “Hi Ascher, not at all, I was just…oh it doesn’t matter. Let me come down to you.” My eyes followed the side-to-side sway of her hips as she climbed down, of her callipygian perfection…god that ass. 

Once she’d come down to my league level, she seated herself on the fifth step easily, crossing her legs and leaning backward. “What’s on your mind, hm?”

That Hellenic accent of hers; a lilting roll of her ‘r’s, a rhythm foreign on this side of the pond…it did things to me, just as much as the valley of her cleavage.

“I’m actually having a pretty tough time with Paz’s assignment,” I chuckled self-consciously…wracking my mind for the right words. “You know, the bridge thing.” 

The bridge thing, Ascher. Nice.

“Yes, I know, the ‘bridge thing’.” Her eyes gleamed golden-orange as her smile widened, stifling a little giggle like she found my outward stupidity endearing. “What’s getting you down?” Tessa’s fingers danced along the silver chain hanging around her neck, a nail tracing lightly over the shape of her collarbone.

I wondered what it would feel like against my lips.

“I got stuck with making the PID controller - ”

“ - ah, so they dumped the hard part on you, Ascher - ”

“ - precisely, and honestly I just can’t get it right. I’m using the formula Paz gave us but it just doesn’t work. Every time I run the sim, the bridge starts oscillating and wobbles like a…I dunno, like a seizing horse. It overcompensates and goes down in the mud. Paz never taught us how to deal with the derivative.”

The last part was an excuse to try and banish my growing sense of dumbness, the feeling that I was just shaming myself in front of the most beautiful girl I’d ever seen over some throwaway differential calc that anyone could do -

“That’s the hardest part,” she pointed out.

Oh.

“...it’s like trying to use math to predict the future based on a panic attack. Everything just starts spiraling, it all gets jammed together and I can’t make sense of it,” I continued, handing her my cellphone - I’d taken a photo of my simulation. Everything she did was graceful, even the way her fingers closed one by one around my Samsung reminded me of a blooming rose viewed in reverse.

“Giving me your phone so freely…wonder if there are some naughty pictures on here,” she mused. Normally this sort of thing wouldn’t phase me but she had my cheeks brighter than a raspberry, and I knew she could see it.

“None that you’ll find.” I tried to sound real cool, and it must have worked; Tessa pushed a string of wildflowers back into her dark hair and pursed her lips with a little ‘ooo’. She handed my Samsung back and pushed off where she was seated, her smiling face inches from mine.

Butterflies and moths fluttered rampant in my belly; she hooked a finger in my belt loop - a shockingly erotic motion that made me bite the inside of my cheek - and tugged me after her. “Come on Ascher. I’m gonna show you why I’m a better teacher than Paz.”

“That’s not hard,” I quipped, drawn along like a moon in her orbit.

I wasn’t oblivious; it was clear as the light from one of those blue rocks that she was flirting with me…but didn’t she flirt with everyone? Had to remind myself that I saw her go home with Liam on Saturday, caught her making out with Jun on Sunday, and last night she and Tara were dancing up on each other at Crucible. 

For her, flirtation was as natural as a sparrow’s flight, her lingua franca; it shouldn’t have felt special because it wasn’t, but it did…like when a celebrity took notice of one of her fans for the first time.

Tessa touched everyone like that (so I presumed) - fingers dancing over chests, her laughter tickling their lips - but the way she did it with me made my heart pound. It made me feel special even though I knew I wasn’t, and I found it as tantalizing as it was humiliating.

“Sooo. We breaking into Paz’s classroom, hacking his computer and making off with an answer key?” I fell in at her side as we left the library; my fingers sought something to grab onto, unsure of what to do with themselves. They wanted to crawl around her waist and pull her closer…they wanted to brush through her hair…they wanted to brush along her jawline, her breath against my lips.

I shoved my hand in my pocket.

“No, silly. That’s cheating…think of this as foreplay.” I almost bit the tip of my tongue off. Foreplay. How does she get this comfortable this fast?

Her hands were clasped behind her back as she strode at my side…ever accompanied by the quiet ‘clp-clop-clp-clop’ of her hooves. “Besides we’re going to Grafton Hall, I wanna show you something cool that gets my point across, yes?” Grafton was only a couple buildings down. The sun had already started its descent Californi-way, so our path was lit by black-hooded street lamps. A spider the size of a squirrel skittered out from under one, watching us peevishly; a tiny green tie hung around its…well, its neck-equivalent. “[Stay away from my lamp!]” it groused. 

I noticed Tessa glance its way dismissively.

I couldn’t find words at that moment, just because of that subtle motion…I’d seen the uh, the creatures interact with each other, like the fox with the blue dresser. I’d never witnessed a person even respond to the things I saw all around me, constantly. 

What did it mean? Was I just hallucinating? Certainly wouldn’t be the first time I’d made a bigger deal over something trifling…

“Ascher?” she asked after a bit - oh god I’d just been staring off, walking silently at her side.

“I was just thinking, our passcards don’t get us into Grafton after 5pm.” Phew, quick recovery.

“Mmm, but I TA with Hunjadi, so I got…” She held up an empty hand, closed her fingers, and opened them again. A little brass key gleamed in her palm.

“This. Just in case she’s too lazy to close up after dinner.”

Impressive sleight-of-hand…I’d seen a lot wilder shit in my time, but this floored me. Probably just the giggle-hots on my part.

“How’d you do that? Where were you hiding it?” I had to ask.

She stopped at the ugly, rusty side door leading into the brick fortress that was Grafton Hall, her expression serious as stone. “I was hiding it in my ass.” She stared me down, unsmiling for a second before bursting out into laughter at her own joke.

What an incredible dichotomy of a woman.

Like a figure from a Gentileschi painting, given elegant life, all soft golds and bronzes…then she cracked an ass-joke (no pun intended). Her laugh was a swaying song that reminded me of a wandering river; raw yet gentle, wild but dignified. 

The two of us stood there, laughing like idiots - that kind where you’re bent forward, tears threatening at the corners of our eyes. Wasn’t even a joke, just…a wildcard moment from Tessa.

I’d never expected anything like that from her, and it only made me fall deeper into her golden spiral.

Then I remembered: I wasn’t hers. She had many lovers to choose from, certainly higher caliber than me. That was what made me cling to the side of the gyre, kept me from drowning.

Even so, my imagination awakened uninvited, and painted a picture where I tugged the door shut behind with a squeaky-clang; in the dark I’d press her against a wall and hear her gasping smile; our lips would meet, fierce and hungry, my hand would slide up her bare thigh to take her hip and press my arousal between her legs -

- the door made a k-thunk as I pulled it shut behind me, leaning my back against it and watching her clop ahead of me…watched her ass sway with each step, which wasn’t helping me control an unwelcome erection. My hands were firmly shoved in my pockets, holding it down against my thigh and trying to look chill as I followed her.

Grafton’s first floor had the characteristic 1970s ugliness of a proper university. The linoleum floor’s color reminded me of gruel mixed with caulk, and glass panels on the walls displayed student projects. 

A pair of gnome-like creatures whose red flesh reminded me of lacquer were maneuvering a gurney through the hallway; a humanoid shape underneath a black tarp twitched, an arm falling to hang off the side of the gurney. Looked like it was made of porcelain; it waved at me as I went by.

We stopped at a door that looked like every other one, and when she cracked the lock we walked into a high-ceilinged room filled with machines I vaguely recognized. The reek of soldering flux hung cloying herein and a trio of big lathes squatted against the wall. Each one cost…well, probably as much as I was paying for my (now questionable) degree. 

Lightbulbs set in grated hangings cast dim illumination from on high, buzzing like insects on a summer night.

“Ever been in here?” she asked playfully, leaning against a bench with a five-axis vice connected to a power supply. Her fingers danced across it affectionately, like a favored musical instrument.

“Not before you invited me in, I don’t think welding is a consideration for my major.” I couldn’t help but pick up a rubber mallet, turning it in my hand idly…just so they could have something to do besides resisting reaching out to touch her.

“You should come hang out sometime Ascher.” Tessa reached out and curled her fingers around the mallet, gently dragging her nails over my knuckles. “Seriously, we do more than just fuck around with blowtorches.” For me that moment was electrical; I wanted so badly to believe that she was showing interest in me but I’ve seen those eyes before, and they weren’t just for me.

I was nothing special to her.

I think she saw the sadness in my smile. I’m pretty shit at hiding my emotions, and there arose this questioning look in her eyes. She was going to ask me what the matter was, I could tell. 

Master of evasion that I was, I turned my attention to the vice. “What’s this thing do?” I let her take the role of teacher again, slid it over her pretty, bared shoulders like a cardigan.

She was too smart to just be distracted, but she let me play my game and wore the professor’s role gracefully. “It’s a vibration testing vice…it’s more or less the real world version of the PIC sim. Look…” there was something so surreal about watching a satyr work a vice like this - you only ever saw paintings of them cavorting, drinking, chasing nymphs. 

Here was one, hallucinated into existence before me, selecting two bars of mild steel that she clamped in.

“This one here on the left,” she began, tightening that section of the vice and adding some bolt-clamps, “is rigidly clenched.” Tessa pulled her lips back with a little smirk. “It’s never good if it’s too tight, is it.” She winked, swinging the mallet in her fingers to the beat of my throbbing heart. “This one’s got some give to it, now…”

She reached out, her fingers on my arm. “Go and ahead, ooo…wow, you work out, don’t you…” Tessa’s attention seemed fully on my bicep, testing it with her strong fingers. 

At the risk of sounding like an addle-brained jock, yes I went to the gym rather obsessively; I’d had this silly vision in my head of arriving in Khamdo in peak condition. Now I just went to focus on something besides the gulf of my future. 

Her attention made me want to giggle stupidly, but I restrained that impulse and grinned stupidly instead. She returned it, like the sun sparkling on a lake, her eyes almost glowing that amber light…and I foolishly wondered if that was for me alone.

“Hit them with the mallet,” she finally suggested, dragging her nails down amidst the crags and lines of definition in my arm before letting go. 

I carefully tapped the steel bar bolted into the machine; it rang sweetly.

“See how it sings? Pleasant, beautiful even, yes? That’s how it tricks you…now.” She gestured at the other bar, almost giddy. That one I struck, and it gave a dull -clank-. “This one tells the unappealing truth, you’ll see.”

Tessa bent forward to plug the vice into the wall-outlet; I couldn’t help myself, staring at the backs of her thighs, disappearing under that shimmery silver dress…the shape of her comely ass was a fixture against my vision - I was literally unable to pull my eyes from it - and she slowly straightened. All the muscles in her back, her legs, they moved under her skin, the flowers strung through her horns glinting like stars in the low-lit chamber.

“Just watch…it won’t take long.” She slid a finger along a black knob, turning it to the right so that the machine vibrated violently. The two metal rods became a blur. 

For a bit we just watched; I sat on a three-leg stool, leaning forward with my elbows on my knees. I was intensely aware of her presence at my side, radiating warmth and an unseen light that eroded my better judgment like a puddle draining into cracked earth.

I wanted to press her against the table behind me and kiss her with chaotic passion, lips crashing against each other without order.

I wanted to push her to sit in one of the stools, slide her skirt up, pull down her panties, and show her what I can do with my tongue.

I wanted to tell her that I’ve been into her from the very first time I saw her, that I loved her horns, her glowing eyes, her hooves. I’d never told one of them - you know, the…Otherfolk, I guess - that I could see the horns, or the fire, or the tree-trunk arms.

I didn’t do any of those things because I had propriety, and of course an unhealthy fear of rejection. 

“So. Who’re those girls I see you with all the time?” Tessa asked casually, never taking her eyes from the noisy vice.

The question caught me off guard; anytime she showed any interest in me did, I didn’t think I’d ever get used to it. “Aryn? Or Vicky?” Those were the first two that came to mind; I didn’t really talk to or see Neave Chen anymore…a sore spot in my heart I steadfastly ignored

“Porque no los dos?” she quipped, turning to gently brush some dust off my shoulder, fingers lingering for a moment, thumbing ash gently from my chin…the gesture was so casual, like something Aryn would do yet utterly unlike her straightforward tomboy-energy.

“Oh they’re just buddies, Aryn has been my friend since we were little and Vicky lived in the room above me Freshman year, so we kinda cliqued up I guess. Get drunk together enough times and it’s kinda inevitable.” No need to tell her I was probably going to end up in Aryn’s bed tonight.

“Mmm. So. You’re single?”

I was. At least, that’s how Aryn and I saw it, our bedroom antics aside.

It would have been easy to just say ‘yep!’ but me being me, I had to stop and overthink it…I knew I was staring at the vice, probably looked like I was ignoring her or hadn’t caught the question like a dolt.

Was she just curious for curiosity’s sake?

Was she interested in making me part of her little man-harem?

Or…against all odds…was she actually interested in me? This stunning, otherworldly woman of my (clearly disturbed) dreams asking me something so…casual. 

I opened my mouth to answer -

-SNAP!-

I felt it like a thunderclap through my shoes.

I watched as the metal bar she’d bolted down tightly broken down the middle, while its partner kept on trembling. “See Ascher…” Tessa unplugged the vice, presenting the broken steel. “Rigidity and too much control, you’ll see how the steel snaps…but this one didn’t, did it.” She laid the solid ingot in my right hand, as if to assure me it was real.

I thought about it for a bit, relating it back to my simulation. It made me think of the bridge, of its struts and supports bolted tightly down, shearing in the wind just the broken steel bar.

All those little disturbances and oscillations, it felt like herding cats; eventually one would get free, then all the others would make their escape and the whole structure fell apart. “So…I think what you’re saying is by trying to control all the variables, I’m overcompensating.”

“You’re overcompensating.” I was suddenly quite aware of her entering my space again, and my eyes met hers - a mistake, as the power of speech seemed to leave me. Her fingers found the hem of my T-shirt, tugging downward on it lightly. “You’re being too careful.” She was close enough that I could feel her breath against my chin.

Seize the bull by the horns.

I watched her eyes flutter just a little as I drew close; I couldn’t hear anything but her breathing, the scrape of her flats against the concrete. Her lips barely brushed mine and just like that a hundred million flowers bloomed in my heart.

Lightning raced from the tip of my tongue down through my chest, striking my loins.

Desire and wanton need clawed at me as my palm found the smooth, tan skin of her waist.

My thoughts became a jumble of simplistic impulse, of wordless erotic imagery. Unadulterated, simple joy.

Spring reigned eternal in my heart for those five seconds.

[stevebattle]

Flexo (2003) by Ted Larson and Bob Allen, CA, USA. Flexo is an early forerunner of the AMPbot.

"It was finally time to make a smaller, improved version of Bender that could do more things. One thing I learned from all my work was that bigger balancing robots are usually easier—since they move slower, the control system doesn’t need to be as exacting in making minor corrections. But making a really tiny balancing robot becomes harder and harder the smaller you go. In the TV show Futurama, Bender has a brother named Flexo. So it made sense to name the new robot after him.

Since I now had a PID algorithm good enough to do things like balance a robot with an offset load on top of it and drive up and down ramps, I could easily mount a moving, pan-tilt-camera rig to the top without any fear of the motion of the camera knocking the robot over. I used a color tracking camera tuned to track the color red, so that if you put a red object in front of the robot, it would try to move toward you. Once it got close enough, it would just stand there and stare at you. We took Flexo to the HomeBrew Robotics Club once he was working, and there was a kid there wearing a red sweatshirt the robot really took a liking to!

Bob thought we might be able to find some companies that might be interested in paying for our expertise in developing these kinds of balancing robots. We bought a booth at the first RoboNexus trade show held in San Jose in 2004. On the first day, we were standing in our booth with Flexo showing off his balancing act, and who should come down the aisle riding a Segway but Dean Kamen himself. He rode up, stopped for a moment, and said jokingly, “Wow! Look at that! I have never seen anything like that!”

On the second day, we met a bunch of enthusiastic engineers from Hasbro. They were looking for more interesting robotic toys they could add to their line, as well as some help with more advanced sensors in toy development. We were invited out to Hasbro corporate headquarters in Rhode Island to give a presentation to the engineering team about what we could do. Bob asked if we needed to prepare a formal presentation, but Hasbro told us to just show up and bring some robots. When we arrived, we were shuttled into an enormous conference room that looked like it could seat 100 people, and there were 20 people sitting in there waiting to hear the presentation that we didn’t have! We thought we’d completely blown it, but we just turned on the robots and Bob started talking. Soon, the crowd warmed up, got out of their seats, and started coming to look at the robots up close, and it all worked out after that. Bob and I started a robotics consultancy called OLogic in 2005 with Hasbro as our first customer." – Ted Larson, From HomeBrew to Hasbro How two friends hacked a balancing robot and wrote a toy story of their own.

[qcsdclabs]

Understanding the Boot Process in Linux

                    Six Stages of Linux Boot Process

Press the power button on your system, and after few moments you see the Linux login prompt.

Have you ever wondered what happens behind the scenes from the time you press the power button until the Linux login prompt appears?

The following are the 6 high level stages of a typical Linux boot process.

                             BIOS        Basic Input/Output System

                             MBR        Master Boot Record executes GRUB

                             GRUB      Grand Unified Boot Loader Executes Kernel

                             Kernel      Kernel executes /sbin/init

                             Init            init executes runlevel programs

                             Runlevel   Runlevel programs are executed from /etc/rc.d/rc*.d/

1. BIOS

BIOS stands for Basic Input/Output System

Performs some system integrity checks

Searches, loads, and executes the boot loader program.

It looks for boot loader in floppy, cd-rom, or hard drive. You can press a key (typically F12 of F2, but it depends on your system) during the BIOS startup to change the boot sequence.

Once the boot loader program is detected and loaded into the memory, BIOS gives the control to it.

So, in simple terms BIOS loads and executes the MBR boot loader.

2. MBR

MBR stands for Master Boot Record.

It is located in the 1st sector of the bootable disk. Typically /dev/hda, or /dev/sda

MBR is less than 512 bytes in size. This has three components 1) primary boot loader info in 1st 446 bytes 2) partition table info in next 64 bytes 3) mbr validation check in last 2 bytes.

It contains information about GRUB (or LILO in old systems).

So, in simple terms MBR loads and executes the GRUB boot loader.

3. GRUB

GRUB stands for Grand Unified Bootloader.

If you have multiple kernel images installed on your system, you can choose which one to be executed.

GRUB displays a splash screen, waits for few seconds, if you don’t enter anything, it loads the default kernel image as specified in the grub configuration file.

GRUB has the knowledge of the filesystem (the older Linux loader LILO didn’t understand filesystem).

Grub configuration file is /boot/grub/grub.conf (/etc/grub.conf is a link to this). The following is sample grub.conf of CentOS.

#boot=/dev/sda

default=0

timeout=5

splashimage=(hd0,0)/boot/grub/splash.xpm.gz

hiddenmenu

title CentOS (2.6.18-194.el5PAE)

          root (hd0,0)

          kernel /boot/vmlinuz-2.6.18-194.el5PAE ro root=LABEL=/

          initrd /boot/initrd-2.6.18-194.el5PAE.img

As you notice from the above info, it contains kernel and initrd image.

So, in simple terms GRUB just loads and executes Kernel and initrd images.

4. Kernel

Mounts the root file system as specified in the “root=” in grub.conf

Kernel executes the /sbin/init program

Since init was the 1st program to be executed by Linux Kernel, it has the process id (PID) of 1. Do a ‘ps -ef | grep init’ and check the pid.

initrd stands for Initial RAM Disk.

initrd is used by kernel as temporary root file system until kernel is booted and the real root file system is mounted. It also contains necessary drivers compiled inside, which helps it to access the hard drive partitions, and other hardware.

5. Init

Looks at the /etc/inittab file to decide the Linux run level.

Following are the available run levels

0 – halt

1 – Single user mode

2 – Multiuser, without NFS

3 – Full multiuser mode

4 – unused

5 – X11

6 – reboot

Init identifies the default initlevel from /etc/inittab and uses that to load all appropriate program.

Execute ‘grep initdefault /etc/inittab’ on your system to identify the default run level

If you want to get into trouble, you can set the default run level to 0 or 6. Since you know what 0 and 6 means, probably you might not do that.

Typically you would set the default run level to either 3 or 5.

6. Runlevel programs

When the Linux system is booting up, you might see various services getting started. For example, it might say “starting sendmail …. OK”. Those are the runlevel programs, executed from the run level directory as defined by your run level.

Depending on your default init level setting, the system will execute the programs from one of the following directories.

Run level 0 – /etc/rc.d/rc0.d/

Run level 1 – /etc/rc.d/rc1.d/

Run level 2 – /etc/rc.d/rc2.d/

Run level 3 – /etc/rc.d/rc3.d/

Run level 4 – /etc/rc.d/rc4.d/

Run level 5 – /etc/rc.d/rc5.d/

Run level 6 – /etc/rc.d/rc6.d/

Please note that there are also symbolic links available for these directory under /etc directly. So, /etc/rc0.d is linked to /etc/rc.d/rc0.d.

Under the /etc/rc.d/rc*.d/ directories, you would see programs that start with S and K.

Programs starts with S are used during startup. S for startup.

Programs starts with K are used during shutdown. K for kill.

There are numbers right next to S and K in the program names. Those are the sequence number in which the programs should be started or killed.

For example, S12syslog is to start the syslog deamon, which has the sequence number of 12. S80sendmail is to start the sendmail daemon, which has the sequence number of 80. So, syslog program will be started before sendmail.

There you have it. That is what happens during the Linux boot process.

for more details visit www.qcsdclabs.com

[alanshemper]

artificial intelligence—defined as "the theory and development of computer systems able to perform tasks that normally require human intelligence"—includes:

linear regression

all of control theory from PID to MPC

lookup tables

if/then code statements

Clippy

[integrating-sphere]

Introduction In modern industry and scientific research, environmental simulation equipment plays a crucial role. These devices can precisely control key parameters such as temperature and humidity, providing a solid foundation for product development, testing, and quality assurance. The “LISUN Temperature and Humidity Test Chamber” stands out in the industry with its superior performance and technological advantages, becoming a trusted choice for many enterprises. This article will delve into various aspects of the LISUN Temperature and Humidity Test Chamber from technical principles, application scenarios, to real-world case studies. Technical Principles of Temperature and Humidity Test Chambers •Temperature Control：One of the core functions of a temperature and humidity test chamber is precise temperature control. This primarily relies on advanced heating and cooling systems. The LISUN Temperature and Humidity Test Chamber employs efficient PID (Proportional-Integral-Derivative) controllers to regulate temperature. The PID controller performs real-time calculations based on the difference between the set value and actual value, adjusting heating or cooling power accordingly to ensure stable and accurate temperatures within the chamber. Additionally, the LISUN Temperature and Humidity Test Chamber is equipped with high-precision temperature sensors such as platinum resistance thermometers (Pt100), providing real-time temperature feedback. These sensors not only have extremely high sensitivity but also maintain stable performance over a wide temperature range, ensuring the reliability of measurement results. GDJS-015B Temperature Humidity Chamber | Thermal Chamber •Humidity Control：Humidity control is equally important, especially in tests involving products sensitive to humidity. The LISUN Temperature and Humidity Test Chamber achieves precise humidity control through steam generators and dehumidification units. Steam generators produce pure water vapor, which is introduced into the chamber to increase the moisture content in the air; dehumidification units remove excess moisture by condensation to reduce humidity. To further enhance humidity control accuracy, LISUN uses intelligent humidity control systems. This system automatically adjusts the intensity of humidification and dehumidification based on changes in environmental conditions, ensuring that humidity remains within the set range. At the same time, humidity sensors (such as capacitive humidity sensors) are used to monitor humidity levels in real-time and feed data back to the control system for timely adjustments. •Chamber Design：Beyond temperature and humidity control systems, the design of the LISUN Temperature and Humidity Test Chamber is meticulously crafted. The chamber body is typically made of stainless steel, offering excellent corrosion resistance and durability. The internal space layout is rational, allowing different shelves and racks to be configured according to varying test requirements, making it convenient to place samples of different sizes. Moreover, the chamber is equipped with sealed doors and observation windows, ensuring the stability of the internal environment while allowing operators to check the test situation at any time. Some models also support remote monitoring functions, enabling users to obtain test data in real-time via network connections, significantly enhancing work efficiency. Application Scenarios of LISUN Temperature and Humidity Test Chamber •Electronic Product Testing：The performance of electronic products is often influenced by temperature and humidity. For example, consumer electronics like mobile phones and computers need to undergo rigorous environmental tests to ensure they function normally under extreme conditions. The LISUN Temperature and Humidity Test Chamber can simulate various environmental conditions including high temperature and high humidity, low temperature and low humidity, helping engineers identify potential design flaws and make improvements. •Materials Science：In materials science research, environmental factors play a critical role in material properties. The LISUN Temperature and Humidity Test Chamber can be used to study the aging, corrosion, expansion, and contraction characteristics of materials under different temperature and humidity conditions. This is significant for developing new materials and extending product life spans. •Agricultural and Food Industry：In agriculture and the food industry, environmental conditions directly impact crop growth and food preservation. The LISUN Temperature and Humidity Test Chamber can simulate climatic conditions of different seasons to study optimal planting schemes for crops and evaluate the impact of packaging materials on food shelf life. •Medical Devices：The safety and reliability of medical devices directly relate to patient health. Therefore, during the R&D process of medical devices, strict environmental adaptability tests must be conducted. The LISUN Temperature and Humidity Test Chamber can simulate actual usage environments such as hospital operating rooms and wards to test the long-term operational stability of devices, ensuring compliance with relevant standards. Real-World Case Studies •Aging Test of Electronic Product：A well-known electronics manufacturer needed comprehensive aging tests before launching a new product. Given that this product would be sold in multiple countries and regions worldwide, facing vastly different environmental conditions, the company chose the LISUN Temperature and Humidity Test Chamber for multiple rounds of testing. By setting different combinations of temperature and humidity, they simulated various extreme environments ranging from cold and dry northern winters to hot and humid southern summers. After several months of continuous testing, technicians identified several design weaknesses and promptly optimized them, ultimately ensuring the market competitiveness of the product. •Development of New Building Materials：A construction company was developing a new type of exterior wall insulation material aimed at improving building energy efficiency. To verify the performance of this material under different climatic conditions, they utilized the LISUN Temperature and Humidity Test Chamber for a year-long experiment. The results showed that this new material not only had excellent insulation properties but also maintained good physical properties under extreme conditions. Based on these research findings, the company successfully launched this innovative product and received widespread acclaim in the market. •Medical Device Certification：A medical device manufacturing company needed to submit a series of documents proving product safety and reliability when applying for CE certification. One critical component was an environmental adaptability test report. The company used the LISUN Temperature and Humidity Test Chamber to conduct six months of continuous testing, recording changes in key indicators. Ultimately, with detailed data support, they smoothly passed the certification audit, laying the groundwork for entering the European market. Future Prospects With advancements in technology and societal development, the demand for product quality continues to rise. In the future, temperature and humidity test chambers will evolve towards greater intelligence and efficiency. For instance, integrating IoT technology to achieve remote monitoring and management of equipment, utilizing big data analysis to predict potential issues and take preventive measures in advance, and even employing virtual reality technology to allow researchers to experience the testing process firsthand, thereby enhancing work efficiency and decision-making accuracy. As a leading brand in the industry, LISUN will continue to invest in R&D, continuously introducing more advanced and environmentally friendly products. It is believed that in the future, the LISUN Temperature and Humidity Test Chamber will play a significant role in more fields, contributing to greater achievements across various industries. Enhancing Efficiency Through Advanced Features •Remote Monitoring and Management：Modern LISUN Temperature and Humidity Test Chambers come equipped with remote monitoring capabilities, allowing users to access test data from anywhere in the world via network connections. Cloud integration allows secure storage and sharing of data, facilitating collaboration among teams located in different regions. This feature is particularly beneficial for multinational companies with distributed R&D centers. Remote monitoring also enables continuous monitoring of environmental conditions in real-world installations. For example, smart city initiatives could use networked test chambers to track the performance of outdoor equipment under various climatic conditions, detecting any issues and scheduling maintenance proactively. •Integration with AI and Automation：Future iterations of test chambers may incorporate artificial intelligence (AI) and automation. These advancements could enable self-calibration and fault-diagnosis capabilities, reducing the need for manual intervention. For example, AI algorithms could automatically analyze measurement data and suggest optimizations based on predefined criteria, streamlining the testing process. Virtual reality (VR) technology could also be integrated into the testing process, allowing users to virtually place test samples in different settings to evaluate their performance before physical prototypes are built, saving time and resources. •Big Data Analysis for Predictive Maintenance：By leveraging big data analytics, LISUN’s test chambers can collect vast amounts of data over time, analyzing trends and patterns to predict potential failures or degradation in performance. This predictive maintenance approach helps companies schedule maintenance activities more efficiently, minimizing downtime and extending the lifespan of both the test equipment and the products being tested. Case Study Expansions • Automotive Industry：In the automotive industry, components must withstand harsh environmental conditions, including extreme temperatures and humidity levels. A major car manufacturer utilized the LISUN Temperature and Humidity Test Chamber to test the durability of their vehicle parts. They exposed various components to cyclic temperature and humidity variations, simulating years of wear and tear in just weeks. This accelerated testing allowed the company to identify weak points in their designs early on, leading to improved product reliability and reduced warranty claims. • Pharmaceutical Research：Pharmaceutical companies rely on precise environmental controls to ensure the efficacy and stability of drugs during production and storage. The LISUN Temperature and Humidity Test Chamber played a vital role in studying the effects of temperature and humidity on drug formulations. Researchers were able to simulate different climate conditions to assess how various formulations responded, ensuring that medications remained effective throughout their shelf life. This contributed to better formulation strategies and enhanced product quality. • Aerospace Engineering：For aerospace applications, materials and components must endure extreme environmental conditions, including vacuum, radiation, and thermal cycling. The LISUN Temperature and Humidity Test Chamber, coupled with other specialized equipment, enabled aerospace engineers to test the resilience of materials under simulated space conditions. This rigorous testing helped ensure that spacecraft components could withstand the harsh realities of space travel, contributing to mission success. Conclusion In summary, the “LISUN Temperature and Humidity Test Chamber” demonstrates its value in modern industry and scientific research through its precise temperature and humidity control capabilities, flexible application scenarios, and numerous practical case studies. Whether in electronics, materials science, medical devices, or other fields, the LISUN Temperature and Humidity Test Chamber provides reliable solutions, helping companies improve product quality and enhance market competitiveness. Facing future challenges and opportunities, LISUN will continue to focus on technological innovation, driving the industry toward new heights. Through meticulous testing and analysis facilitated by tools like the LISUN Temperature and Humidity Test Chamber, we can expect continued improvements in product reliability, safety, and overall quality, paving the way for smarter and brighter futures. By incorporating advanced technologies and continuously refining their products, companies like LISUN contribute to the advancement of industries ranging from automotive to architecture, ensuring that testing solutions are not only functional but also sustainable and user-friendly. Read the full article

[rohan9794]

Shrink Tunnel Machine: The Ultimate Guide to Seamless Heat Shrink Packaging

What is a Shrink Tunnel Machine? A shrink tunnel machine, also known as a heat shrink tunnel, is a packaging system that applies controlled heat to shrink plastic film (typically PVC, POF, or PE) wrapped around a product. As the product passes through the tunnel on a conveyor belt, hot air circulates uniformly, causing the shrink film to tightly conform to the product’s shape, creating a secure, tamper-proof seal.

Working Principle of a Shrink Tunnel Machine Product Wrapping: The product is first wrapped in shrink film using a sleeve sealer, L-bar sealer, or manually.

Conveyor Entry: The wrapped product enters the shrink tunnel via a heat-resistant conveyor.

Uniform Heating: The tunnel's heating elements blow hot air through nozzles or fans, activating the film’s memory to shrink.

Cooling & Exit: The product exits the tunnel, where the film cools and tightly conforms to the shape.

Types of Shrink Tunnel Machines

Electric Shrink Tunnel Powered by electricity.

Ideal for small to medium-scale industries.

Energy-efficient and simple to maintain.

Steam Shrink Tunnel Uses steam as the heat source.

Preferred for PVC or PETG labels and beverage bottles.

Ensures gentle and uniform shrinking—great for delicate packaging.

Infrared Shrink Tunnel Uses infrared rays for rapid and uniform heating.

Suitable for thin, heat-sensitive shrink films.

Gas Shrink Tunnel Uses LPG or natural gas as heating medium.

Suitable for large operations needing faster heating at lower operational cost.

Key Features of Shrink Tunnel Machines Adjustable Temperature Control: Precise heat application to avoid film damage.

Variable Conveyor Speed: Matches line speed and product type.

Dual Insulation System: Reduces heat loss and energy consumption.

PID Temperature Controller: Maintains consistent heat for high-quality finish.

Heavy-Duty Conveyor Belts: Supports different product weights and sizes.

Built-in Cooling Fan (Optional): Ensures faster setting and better finish.

Stainless Steel Frame: Hygienic, rust-free, and ideal for food or pharma packaging.

Applications of Shrink Tunnel Machines Beverage Bottles: Neck banding and full-body sleeve labeling.

Pharmaceuticals: Tamper-evident shrink bands on caps and containers.

Food Packaging: Bundling of bottles, trays, and cans.

Cosmetics: Shrink wrapping tubes, boxes, and gift sets.

Stationery & Toys: Wrapping products in display-ready packs.

Consumer Electronics: Tight, dust-proof wrapping for gadgets.

Benefits of Using Shrink Tunnel Machines ✅ Enhanced Product Presentation: Clean, wrinkle-free finish that enhances brand appeal.

✅ Tamper Evidence: Secure packaging deters counterfeiting and tampering.

✅ Moisture and Dust Protection: Seals out contaminants and preserves freshness.

✅ Bundling Capability: Wrap multiple items together for easier handling.

✅ Extended Shelf Life: Preserves packaging integrity during transportation and storage.

✅ Compatibility with Various Films: Works with PVC, POF, PE, and PET shrink films.

✅ Integration-Ready: Easily connects with existing sealing and labeling lines.

Shrink Tunnel Machine Technical Specifications Parameter Specification Range Conveyor Speed 0–25 meters per minute (adjustable) Tunnel Dimensions Varies from 1000mm to 2000mm (length) Power Source Electric / Steam / Gas Power Consumption 3 – 20 kW (depending on tunnel size) Temperature Range 0°C to 300°C Conveyor Load Capacity Up to 50 kg Film Compatibility PVC, POF, LDPE, PETG Machine Material Mild Steel / SS304 or SS316 for hygiene

Top Manufacturers of Shrink Tunnel Machines in India Harikrushna Machines

Shree Bhagwati Packaging

Sevana Packaging Systems

SS Automation & Packaging

Labh Group of Companies

Multipack Machinery Co.

These manufacturers provide custom-built solutions for startups and large-scale industries, ensuring high efficiency, reliable output, and local service support.

Shrink Tunnel Machine Price in India (2025) Machine Type Price Range (INR) Manual Shrink Tunnel ₹25,000 – ₹60,000 Semi-Automatic Tunnel ₹80,000 – ₹1.5 lakh Fully Automatic Tunnel ₹2 lakh – ₹6 lakh Steam Shrink Tunnel ₹3 lakh – ₹8 lakh Customized Tunnel System ₹6 lakh – ₹15 lakh+

Prices depend on capacity, size, heating source, conveyor type, and automation level.

How to Choose the Right Shrink Tunnel Machine ✅ Know Your Film Type: Choose machine type based on film—PVC, POF, or PE. ✅ Assess Throughput Needs: Match conveyor speed and heat capacity to production volume. ✅ Consider Product Size: Ensure tunnel dimensions suit the largest product. ✅ Check Energy Consumption: Balance efficiency with operational costs. ✅ Select Material Build: Opt for stainless steel in food and pharma industries. ✅ Look for Safety Features: Emergency stop, overload protection, and insulation.

Maintenance Tips for Shrink Tunnel Machines Clean heater coils and fans weekly.

Lubricate conveyor chains regularly.

Calibrate temperature settings based on ambient conditions.

Check electrical connections and insulation monthly.

Replace worn-out shrink film rollers promptly.

Latest Innovations in Shrink Tunnel Packaging IoT Integration: Real-time monitoring of temperature, speed, and performance.

Servo Motor Control: Precise conveyor motion for delicate items.

Energy Recovery Systems: Minimizes power consumption and heat loss.

Modular Tunnel Design: Easy to expand or upgrade based on demand.

Environmentally Friendly Films: Compatible with biodegradable shrink wraps.

Conclusion The shrink tunnel machine is a powerful asset in modern packaging lines, offering not only professional and tamper-proof product finishes but also speeding up operations while ensuring product safety and branding excellence. Whether you’re a small business or a large manufacturer, investing in a shrink tunnel system will drastically improve your packaging process and brand image

[renatoferreiradasilva]

FRITAR COXINHA

🔬🖍️ Protocolo Experimental Revisado: Simulação Termofísica de Reentrada Hipersônica com Análogos Alimentares

🎯 Título do Projeto

"Validação de Análogos Alimentares para Simulação Termofísica de Reentrada Hipersônica: Modelagem Experimental e Computacional"

1. 🔍 Hipótese Científica Revisada

A fritura profunda de coxinhas padronizadas simula fenômenos termofísicos de reentrada hipersônica, com correlações quantificáveis em:

Formação de camada ablativa (crosta)

Gradientes térmicos multiescalares

Emissividade infravermelha detectável

Perda de massa por ablação

2. ⚙️ Materiais e Equipamentos (Atualizado)

CategoriaItensAmostras- Coxinhas sintéticas (esferas de polimetacrilato Ø50mm revestidas com camadas controladas de farinha: 1mm, 3mm, 5mm) - Coxinhas tradicionais (grupo controle)Sensores- Câmera térmica FLIR A315 (ε ajustável) - Termômetro de imersão ISO-calibrado - Balança analítica (±0.001g)Sistema de Fritura- Banho termostatado com óleo (controle PID de temperatura) - Recipiente fechado com janela de safira (transmissividade IR >90%)Análise- Software COMSOL Multiphysics® (módulo Heat Transfer) - Kit análise de imagem (ImageJ + script Python para rugosidade)

3. 🧪 Procedimentos Experimentais (Aprimorados)

🔬 Etapa 0: Preparação Teórica

Coletar dados de referência de reentrada hipersônica (NASA TP-2022-XXXX)

Simular perfil térmico esperado no COMSOL (condições: Mach 8, ângulo 30°, atmosfera padrão)

⚖️ Etapa A: Padronização de Amostras

Fabricar 30 esferas sintéticas com revestimentos controlados (10 por espessura)

Caracterizar inicial:

Massa (±0.001g)

Rugosidade superficial (Ra via perfilometria)

Emissividade (método ASTM E1933)

🌡️ Etapa B: Perfis Térmicos Dinâmicos

FaseTemperatura ÓleoDuraçãoAnálogo de ReentradaInicial180°C ±2°C90sCamadas atmosféricas superioresCrítica220°C ±2°C60sCamada de máximo aquecimentoFinal190°C ±2°CAté términoFase de desaceleração

Protocolo:

Registrar a cada 15s:

Temperatura superficial (FLIR)

Temperatura interna (sonda)

Massa (balança de imersão)

Monitorar formação de bolhas (taxa de frames: 60fps)

📀 Etapa C: Análise Pós-Experimento

Caracterização da crosta:

Espessura (micrômetro digital)

Porosidade (análise de imagem em corte transversal)

Correlação térmica:# Código para cálculo de similaridade térmica def calcular_similaridade(perfil_coxinha, perfil_reentrada): # Alinhamento dinâmico temporal (DTW) correlation = np.corrcoef(perfil_coxinha, perfil_reentrada)[0,1] rmse = np.sqrt(mean_squared_error(perfil_coxinha, perfil_reentrada)) return correlation, rmse

4. 📊 Matriz de Dados (Expanda)

VariávelMétricaInstrumentoFrequênciaTemperaturaT_superfície, T_núcleoFLIR + Termopar15sMassaΔm (g/s)Balança analítica30sEmissividadeε(λ) 3-5μmFLIR (calibrado)ContínuoMorfologiaEspessura crosta, Ra (μm)Micrômetro + ImageJPós-testeAssinatura IRHistograma térmicoScript PythonPor frame

5. ⚠️ Protocolo de Segurança

Contenção de óleo:

Usar recipiente com fechamento magnético e válvula de alívio

Escudo térmico para operador durante medições FLIR

EPI Obrigatório:

Óculos de proteção IR

Avental resistente a óleo quente

Luvas termorresistentes (Kevlar®)

6. 📈 Análise de Dados (Aprofundada)

Modelos Matemáticos:

Taxa de ablação: m˙=k⋅(Tsurface−T∞)n (Regressão não-linear para determinar k, n)

Eficiência de proteção térmica: η=∫0tqconvdt−ΔHabl∫0tqconvdt Onde:

qconv=h(Toil−Tsurface)

ΔHabl=m˙⋅Lv

Validação Computacional:

Comparar gradientes térmicos experimentais vs. simulação COMSOL

Análise de sensibilidade: espessura de revestimento vs. tempo de falha térmica

7. 🔗 Fundamentação Teórica

Referências-Chave:

Reentrada Hipersônica:

ANDERSON, J. D. (2019). Hypersonic and High-Temperature Gas Dynamics. 3rd ed.

NASA TP-2022-XXXX: Thermal Protection System Modeling for Mars Entry

Materiais Ablativos:

KOO, J. H. (2018). Polymer Nanocomposites as Ablative Materials. Elsevier.

ZHANG, X. et al. (2021). Carbon-Phenolic Composites Ablation under Plasma Torch. J. Spacecraft Rockets.

Metodologias Experimentais:

VOLLMER, M.; MÖLLMANN, K. P. (2017). Infrared Thermal Imaging: Fundamentals, Research and Applications. Wiley-VCH.

ASTM E457: Standard Test Method for Measuring Heat Transfer Rate Using a Thermal Capacitance (Slug) Calorimeter

8. 🧬 Extensão para Modelagem AI

graph LR A[Dados FLIR] --> B(Pré-processamento) B --> C[Redução dimensional - PCA] C --> D{Modelo de Classificação} D --> E[ResNet-50] D --> F[Vision Transformer] E & F --> G[Identificação de padrões críticos] G --> H[Correlação com dados reais de reentrada]

📥 Produtos Esperados

Banco de dados público de termogramas de fritura

Plugin para ImageJ: CrustAnalyzer (quantificação morfológica)

Modelo preditivo open-source de formação de crosta

Protocolo didático para laboratórios de engenharia aeroespacial

"Este protocolo integra metodologias experimentais rigorosas com modelagem computacional, transformando uma analogia culinária em ferramenta válida para estudos termofísicos iniciais."