#Quantitative Reasoning

[recsspecs]

Source: Cracking the GRE Premium Edition with 6 Practice Tests, 2020 All the best to everyone for your upcoming exams

[man-and-atom]

The company plans to use solar farms in places that have little to recommend them other than a railway line nearby as filling stations at which to charge heavy but cheap batteries built into goods wagons. A 100-car train… could deliver three gigawatt-hours to users.

We wouldn’t normally suspect The Economist of innumeracy. On the other hand, solar boosters are hardly above suspicion of deliberate deception, and sometimes seem to revel in self-deception.

American railroad hopper-cars, much larger than those used most other places in the world, carry typically 100 tonnes of coal each. A modern, efficient gigawatt coal-fired power station typically burns something like 300 tonnes of coal an hour. (Those numbers will vary with the thermal efficiency of the station and the quality of the coal.) Three gigawatt-hours would then require about 10 carloads. The typical unit coal train is 100 cars long, or about 30 gigawatt-hours. At that, most of the coal-burners built in the past half-century or so have been mine-mouth stations, because for distances of about 500 km or less, it’s cheaper to burn the coal at the pit-head and send the power onward by high-tension lines.

Good lead-acid batteries (presumably the “heavy but cheap” option mentioned) store about 50 watt-hours (0·05 kWh) per kilogram. At this rate, one train car could carry a freight of 5000 kWh. The whole trainload would then be 100 times that, 500 000 kWh or half a gigawatt-hour. Only if you assume an externally-imposed economics-be-damned mandate for solar-plus-storage, as in California, does this begin to make some kind of sense.

If the numbers as given simply don’t seem to accord with reality, neither does the claim that solar “only gets cheaper and cheaper”. Solar power requires land, and vast tracts of it — land which only tends to increase in price. Besides that, each additional increment of generation tends to use more land, because the land most favorable for the purpose is usually developed first. Similarly, the vast raw materials requirements call for exploiting poorer and poorer sources, at ever-escalating costs.

Compare all that with a single half-meter-long CANDU fuel bundle, containing about 30 kg of uranium, which in the course of its time in the reactor will produce more than 1 500 000 kWh. Nuclear requires only modest quantities of land and raw materials, and depends primarily upon technological skill and know-how — which, unlike land or raw materials, constantly gets cheaper.

[gil-estel]

trying to research PhD programs but struggling bc my area of interest (the science of how children learn math) is grouped in different degree programs depending on the university (edpsych, psych, cognitive science, human development) so I end up having to look up every single faculty member across like 3 different departments for each potential university 😭

[anghraine]

"You only don't like vegetables because you've never had them prepared properly"

"You only don't like math because you've never been taught properly"

Once y'all are done insulting my mother, you might want to consider that you don't know other people's lives?

[amurder-ofcrows]

ok so i got an hour and a half of sleep last night between 12am and 1:30am bc im crashing into mania again (yes i called my psychiatrist and therapist) but like shout out to middle of the night me for actually writing down a sentence stuck in my head in my notes app that reads “i am my father’s daughter and my mother’s son” bc oooh i have some writing ideas with that

[man-and-atom]

French electricity continues to be far cleaner, as well as considerably cheaper, than German electricity.

It’s very easy to fall into the trap of seeing what one wants to see, and many people desperately want to see “cheap, clean renewable energy as the solution to climate change”. But if we really want to solve the pressing problems of the world, it is vital to see what is actually there.

There was record-breaking clean energy progress all around the world in 2024

"Last week, we shared the news that the U.S. government permanently closed most federal waters — more than 625 million acres — to offshore oil and gas drilling.

It’s a great way to kick off a year of more good climate action. And as the year-end data rolls in, there are even more stories of progress in fighting climate change via transitioning away from fossil fuels toward clean energy sources across the globe. In 2024...

📍 In Great Britain, wind power alone provided more electricity than ever before, and all renewables together generated around 56% of electricity.

📍 In Germany, renewables made up a record 59% of electricity generation and became the “backbone of the system” in the country.

📍 In Poland, a record 29% of its power came from renewable sources, showing great progress in a country that still heavily relies on coal.

📍 In India, the “transformative growth” of its renewable energy sector led to it surpassing 200 GW of installed capacity, making up 46% of the country’s total installed capacity.

→ Read more stories of progress for the planet"

-via GoodGoodGood, January 18, 2025, Source

[raskies456]

GRE today…..

[knxfesck]

something something you need to be critical of the sex offender list

[twinsunsintatooine]

IM SO HAPPYYY!!! I ATE UP THE UCAT!!!!

[man-and-atom]

Chernobyl did something amazing which most people seem incapable of realizing : it showed us that even the worst conceivable nuclear disaster wasn’t anything like as bad as we had thought.

A little background : back in 1958, the US Atomic Energy Commission published a report known as WASH-740. This was intended as a look at the worst possible consequence of a nuclear power plant accident, and so it postulated the sudden dispersal into the environment of the complete core of a 200 MW light-water reactor. This isn’t something that could actually, physically happen. But it was predicted that 3400 deaths and 43 000 injuries would result.

As it turns out, the RBMK-1000 reactor type had a unique design such that, under certain very unusual conditions, it was possible to disperse about 1/5th of the core of a 1000 MW reactor. Every other type of power reactor ever approved for civilian use is designed and constructed so that such an event is made impossible by the laws of physics ; but the Politburo wanted large reactors now, and when they were warned by the Chief Designer that the calculations weren’t complete, they thought it would be adequate to issue an operators’ manual saying “never for any reason do this”.

In other words, what happened at Chernobyl 38 years ago was beyond the worst nuclear accident that anyone thought could happen, or indeed, that could have happened anywhere else.

Now here’s the really important part. The United Nations Scientific Committee on the Effects of Atomic Radiation has made careful study of the people affected over those 38 years. Estimates of exposure, for instance, have been made for people exposed to the debris cloud, and their health has been compared to the health of unexposed populations from the same region, with the same demographics, diet, et cetera. Furthermore, the “liquidators”, a workforce of well over a hundred thousand people who were sent in to do cleanup, and received the largest allowable radiation dose before being pulled out, have been followed all that time.

The expected harms to human health have failed to appear.

Among the liquidators, for instance, it was confidently expected that, within about 10 years, a very large number of cases of leukemia would be seen, because this is the kind of cancer most likely to be caused by radiation. There should have been what epidemiologists call a large signal, a statistically unambiguous number of cases, several times larger than the number which would occur at random in an unexposed population. All these years later, we’re still waiting to see those cancers.

In face, Greenpeace and others have accused UNSCEAR of a cover-up, because the estimates of deaths and injuries keep getting revised downward in every successive report. Apparently they don’t understand how the scientific method works. Correlation does not necessarily imply causation, but the lack of correlation is very good evidence against causation.

Meanwhile, knowledge of the very real harms of fossil fuels, and of air pollution — which nuclear power plants do not produce — continues to mount.

Civil nuclear energy has never caused any event comparable to the 1952 London smog, and the evidence of Chernobyl is that it cannot.

Oh hell yeah

[man-and-atom]

This hourly diagram of electricity production and emissions for eleven European countries over the course of 2023 is honestly fascinating.

The lowest emissions, unsurprisingly, are found in Norway (hydro), Sweden and Switzerland (hydro plus nuclear, although Switzerland has yet to abandon its “nuclear phase-out” policy), and France (nuclear). The highest are in Poland, which burns coal very heavily. And Germany varies wildly.

But we can also see, for instance, that Poland has a very narrow range in its production of electricity. So does Denmark, perhaps suprisingly ― although, contrary to what you might expect, Denmark is not among the top 10 countries in the world by share of wind power, according to OECD-IEA. We can guess that Norway’s very broad range of output variation reflects the use of its hydro plants to follow the variations in the Danish load.

Belgian output is also in a fairly narrow band, and we can likewise guess that a part of the large variation in French output is to compensate for that. German output, on the other hand, is all over the map because of variations in supply, not correlated with load.

What inferences can you draw?

[mildew-dread-mold]

me (computer science student) asking my friend (humanities major) arithmetic problems (what’s 2^18, what’s 76-12, what’s 1207/18, etc) 🤝 my friend (aforementioned) asking me (me) how to do in text citations

[medsocionwheels]

Sociological Theory and the Canon

It's Sociology Sunday! Today we're talking theory.

What is sociological theory?

Sociological theory is a set of interrelated ideas that allow for the (1) systematization of knowledge of the social world (2) the explanation of that world, and (3) predictions about the future of that world, and which are falsifiable through empirical research.

Theory provides a possible answer to questions like, “why did this happen?” or, “why did they do that?” This means theory is speculation, not fact, but unlike “ideas” generally, theory is speculation driven by a more formal, systematic, process, which incorporates the work of previous theorists and research findings.

The Sociological Canon

Some theories are more popular than others. Some theories, while unpopular, are considered “pivotal” to the foundation of sociology. The “sociological canon” helps us identify the “popular” and “pivotal” theories.

The sociological canon is defined as the theories, ideas, and texts that are widely considered as the most important in the field of sociology (Ritzer and Stepnisky 2018) 

“I’m not a regular mom theory, I’m a cool mom theory!”

The canonized theories are sort of like the “cool mom” in Mean Girls (oshowing my age here, the original 😘) – others exist, but these are the ones we tend to think of first when we think of “the mom in Mean Girls” (or, in this case, “sociological theory”).

Critics of the canon argue that the canon is not a neutral construction; rather, it is affected by power and the politics of the theory. To some degree, they are right.

The field of sociology has historically privileged theories that have testable hypotheses, known as “positivist” theories, and theories produced by white men faculty. In this, we can see that the canon, and relatedly, the field of sociology,  have tended to reflect power structures in society more broadly. Which means that, yes, technically the canon is full of theories created by old white dude philosophers in Europe in the late 1800s to early 1900s. Nowadays, though, most sociologists agree that the canon includes much more than Marx, Weber, and Durkheim. 

Meaning the canon is now considered to  include theories from other classical theorists writing during the same time as Mark/Weber/Durkheim, like W.E.B. DuBois and Ida B. Wells. The canon has also expanded in the last 40 or so years to include contemporary theories, such as emancipatory, feminist, and queer theories. These expansions were important steps towards accounting for the reality of the field as it presently exists, and to correctly reflect the field’s foundations which expand far beyond whiteness, masculinity, and western imperial culture. Presently, women make up the (quantitative) majority of sociology faculty, and while this women majority was historically white, the number of women, including and especially women of color, in sociology continues to grow, substantially outpacing white men. 

Sociological Theory and Empirical Research

Empirical research is rooted in theory.

Sometimes these theories are the driving force behind research, constituting the research question for an empirical study. You begin with the possible answer to the question, the theory, and you investigate to see if it holds up–your results may call into question some or all of the theory’s propositions. This is called “deductive reasoning.”

Theory is not always the starting point of research, though. Sometimes theory is generated from research. This process is called “inductive reasoning.” In this case, you begin with observations, draw conclusions, and from those conclusions, generate new ideas about the social world. 

Deductive reasoning is often linked with quantitative research. Quantitative researchers usually have some idea of theory before forming their research question, and some quantitative research is constructed with the goal of testing (falsifying) theoretical propositions.  Qualitative research, in contrast, often uses inductive reasoning, beginning with observation and developing theory as part of the study’s conclusions. This is not always the case with qualitative research, though. One approach to creating contemporary sociological theory assumes the “best” theory is constructed via inductive reasoning, and thus, begins with observation, absent of pre-existing ideas. This is known as a “grounded theory” approach, because it produces theory that is “grounded” in observation of tangible facts instead of based upon pre-existing abstract ideas. The sociologists Barney Glaser and Anselm Strauss are often credited with popularizing the “grounded theory” approach, which they outlined in their 1967 book “The discovery of grounded theory: Strategies for Qualitative Research”.

Other approaches to qualitative research, like content analysis, may start with theory or observations.

Summary:

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A post shared by Dr. Heather Sue M. Rosen (@medsocionwheels)

Watch full lecture:

[man-and-atom]

Well, that’s at least less unreasonable than I was thinking.

It appears that the idea of large–scale carbon capture for sequestration is not something that one can say much of anything sensible about at the present time.

The economics of any kind of peaking plant, on the other hand, always have to compete with part–loading a baseload–capable power plant. This is, I hasten to observe, true because we have a zero–emissions baseload power technology available and well proven. In other words, to minimize emissions of CO₂ to the atmosphere, the much–discussed “transition to renewable energy” is not the only option.

Now, in a scenario where nuclear is allowed, the relevant cost comparison may well be, not between solar plus “Terraformer” plus gas turbine and solar plus battery, but between nuclear plus “Terraformer” plus gas turbine and part–loaded nuclear. Now, we can reasonably expect any nuclear power plant of established types, built at the present time, to operate 60 years (unless shut down by political mandate), with a major refurbishment at 30 years.

Unfortunately, the question of how much a new nuclear plant costs is hard to settle. There are not enough current projects to supply meaningful data. Suppose $60 per watt installed, which is on the high end, although not the absolute highest (thus giving a generous allowance for the mid–life refurbishment and other costs). Then straight–line depreciation for 60 years gives $1 per annual watt–year. Part–loading that plant at 50% annual load factor would only double that cost. $2 per annual watt–year is somewhat higher than the figures being advanced for the carbon–capture/gas–turbine system, and which option is really preferable probably ends up being a matter of the specific situation. At $15 per watt (at the low end for current projects, but there is good reason to think that costs could be reduced substantially from there), baseload is 25¢ per annual watt–year, 50¢ at half load, and the case for the peaker is difficult to make out.

It certainly does not appear that there is an overwhelming case that can be made for using the “Terraformer” system, as compared to equipment which is already well proven in service. And for my part, I tend to view all carbon–capture schemes, and especially schemes for compensating for the intermittency of wind and solar with combustion equipment, as ways to justify not taking rapid effective steps away from fossil fuels.

when will we see the first reverse coal baron (negacoal?) who owns vast pits that armies of filthy labourers carefully stack full of carbon bricks spat out of vast capture machines sucking in CO2 from the sky

[luvrxbunny]

it doesn’t get better

i’m 18 and still crying over math homework

[edwisefoundation]

Key GRE Exam Timings and Tips for Better Time Management

The GRE exam requires effective time management to perform well across its multiple sections, which total around 3 hours and 45 minutes. Understanding the GRE exam timings for each section—like Analytical Writing (60 minutes), Verbal Reasoning (60 minutes), and Quantitative Reasoning (70 minutes)—can greatly enhance your preparation. Additionally, be aware of the unscored section, which appears randomly but doesn't count towards your score.

For a detailed breakdown of each section’s timings and tips for success, visit this page.