mechanicalengineerstudyphysics

[mechanicalengineerstudyphysics]

機械系課程複習流程

五大力學

靜力學

動力學

熱力學

流體力學

材料力學

基本學科

工廠實習

工程圖學

工程數學

機動學

工程材料

機械製造

機械設計原理

熱傳學

自動控制

進階學科

電工學

應用電子學

振動學

能源工程

高等材料力學

[mechanicalengineerstudyphysics]

機械相關開放課程

一些相關連結的紀錄。

基礎科目：

微積分：數學工具

中央大學：微積分(i)-單維彰；微積分(ii)-單維彰

台灣大學：微積分（數學系）朱樺

普通物理學：基礎物理原理

台灣大學：普通物理學（張寶棣）；普通物理學（易富國）

工程數學：進階的數學工具

交通大學：工程數學(一)；工程數學(二)

台灣大學：工程數學 - 微分方程；工程數學 - 複變；工程數學二

工程圖學：

工程圖學 (Fall 2016)--劉俊賢 / 清大

進階科目：

工程力學（包括靜力學、動力學與材料力學等）

葉銘泉-應用力學(一)(靜力學)

葉銘泉-應用力學(二)(動力學)；Intermediate Dynamics (ME 4160)

葉銘泉-材料力學；Strength and Mechanics of Materials (ME 2141 & ME 2191)

Introductory Continuum Mechanics by Romesh C Batra, VA Tech

Engineering Fracture Mechanics (Video) 

熱力學與熱傳學（包括熱機）

Thermodynamics I

王訓忠-熱傳學；Intermediate Heat and Mass Transfer

流體力學與流體機械

王訓忠-流體力學

Fluid Mechanics (ME 3111 & ME 3121)

NOC:Advanced Fluid Mechanics  (Video)

機動學與機械設計

MEEG 4104 - Machine Element Design

Design of Machine Elements I

Robotics (Video)

工程材料與機械製造

陳智-材料科學與工程導論 (一)

楊宏智-機械製造

Manufacturing Processes I (Video)；Manufacturing Processes II (Video)

電工學（包括電機機械） 

潘晴財-電路學

葉廷仁-電動機械(一) 

電子學-陳振芳

自動控制

非線性控制系統－程登湖

ME233 Advanced Control Systems II, UC Berkeley, Spring 2016

參考來源

sleeper的學習筆記

雲端理工學院

InfoCoBuild

[mechanicalengineerstudyphysics]

重要的是，要知道這裡探討的問題和聰明與否無關。科學家、醫生和大眾健康官員往往認為那些不同意科學結論的人一定都��笨，導致以這種偏見設計出的教育措施都流於過度簡化，或甚至帶些優越感。但是，那些最聰明的人其實也會避免複雜性和不想深究科學細節。

[mechanicalengineerstudyphysics]

People often ask, what exactly do you mean by “breakthrough”? It’s a reasonable question—some of our picks haven’t yet reached widespread use, while others may be on the cusp of becoming commercially available. What we’re really looking for is a technology, or perhaps even a collection of technologies, that will have a profound effect on our lives.

[mechanicalengineerstudyphysics]

當九月一日，納粹德國入侵波蘭，英法對德宣戰，大戰又爆發的消息傳開時，他嚇壞了。Chadwick可不想再一次在拘留營中渡過戰爭的歲月，所以他以最快的速度前往Stockholm，但當他與家人到達時，所有連接Stockholm與倫敦的空中交通已被中止。他們一家最終總算有驚無險坐著貨船回到英國。

[mechanicalengineerstudyphysics]

(經由 https://www.youtube.com/watch?v=7oaGUg7ik_c)

[mechanicalengineerstudyphysics]

[熱力學]第二週筆記：First Law of Thermodynamics

Ch 2 First Law of Thermodynamics

Conservation of energy: energy can be neither created nor destroyed during a process

$$\Delta E_{system}=E_{in}-E_{out} $$

2.1 Forms of energy

E: total energy of a system (Unit: J, kJ)

$e=\frac{E}{m}$(Unit: J/g, kJ/kg)

Macroscopic form

a system as a whole with respect to some outside reference frame

kinetic energy (work done by inertial force): $$KE=\frac{1}{2}mv^2,ke=\frac{1}{2}v^2$$

potential energy (work done by conservational force, e.g. gravitational force):$$PE=mgz,pe=gz$$

Microscopic form

molecular structure of a system, independent of outside reference frame

internal energy $U~,(~per~unit~mass~)~u= \frac{U}{m}$

effected by internal molecular activity such as molecular translation, rotation & vibration

Detail analysis awaits statistical mechanics

請去物理系讀？其實高等熱力學也有啦XD

$Total~energy :E=U+KE+PE=U+\frac{1}{2}mv^2+mgz$ $Total~energy~per~mass :e=u+ke+pe=u+\frac{1}{2}v^2+gz$

Energy - state property: definite value for each equilibrium state completely specified by two independent, intensive properties.

$$\Rightarrow~\Delta E=E_{final}-E_{initial}=\int_{initial}^{final}dE$$

dE : exact differential of energy

The above integral is Path independent

Stationery system

closed system whose velocity and elevation of the center of gravity remain constant during a process

$$\Rightarrow~\Delta KE=\Delta PE=0~\Rightarrow \Delta E=\Delta U~for~a~stationery~system $$

Rate of change of energy

$$\lim_{\Delta t\to0}\frac{\Delta E}{\Delta t}=\frac{dE}{dt}$$

2.2 Mechanisms of energy transfer, $E_{in}$ & $E_{out}$

Heat, Q: energy transfer by virtue of a temperature

Work, W: energy transfer associated with a (non-conservative) force acting through a distance

mass flow (open system)

1. Heat, Q, (heat transfer per unit mass ) $q=\frac{Q}{m}$

Formal sign convention

Heat transfer to the system: $Q=|Q|\overset{def}{=}Q_{in}\geq0$

Heat transfer from the system: $Q=-|Q|\overset{def}{=}-Q_{out}\leq0$

$$Q_{in}~and~Q_{out}:amount~of~heat~transfer~entering~and~leaving~the~system~respectively$$

Rate of heat transfer, or heat transfer per unit time, $\dot Q$

unit: J/s=W, kJ/s=kW $$Q=\int_{t_{initial}}^{t_{final}}\dot Qdt~or~Q=\dot Q\Delta t~as~\Delta t\rightarrow 0$$

The amount of heat transfer: path dependent

heat transfer: path function$$Q=\int_{t_{initial}}^{t_{final}}\delta Q$$

$$\delta Q: inexact~differential ~of~heat~transfer$$

Mechanism of heat transfer

Conduction: transfer of energy from the more energetic particles of a substance ==adjacent== less energetic ones.

$$\dot Q_{conv}=hA(T_s-T_f)$$$$h: convection~coefficient$$$$T_s ,T_f=temperature~of~solid~and~fluid,respectivily$$

Convection: transfer of energy between a solid surface and the adjacent fluid that is in motion

Fourier's law:$$\dot Q_{cond}=-kA\frac{dT}{dx}$$$$k: thermal~conductivity;~A: contact~surface~area$$

大三必修：熱傳

Radiation: transfer of energy of a electromagnatic waves

Stefan-Boltzmann law:$$\dot Q_{emit}=\sigma \epsilon A T^4 \Rightarrow \dot Q_{rad}=\sigma \epsilon A (T^4-T_{sur}^4)$$$$\sigma :Stefna-Boltzmann~constant=5.67\times10^{-8} W/m^2K^4 $$$$\epsilon : emissivity~(0\leq\epsilon\leq1)$$$$T_{sur}=temperature~of~surrounding$$

2. Work, W ,$w=\frac{W}{m}$

$$W=\int_{s_{initial}}^{s_{final}}\vec{F~}\dot~ d\vec{s~}$$

Formal sign convention

Work done on the system: $W=-|W|\overset{def}{=}-W_{in}\leq0$

Work done by the system: $W=|W|\overset{def}{=}W_{out}\geq0$

$$W_{in}~and~W_{out}:amount~of~work~done~on~and~by~the~system~respectively$$

Work done per unit time; Power(Unit J/s=W)

$$W=\int_{t_{initial}}^{t_{final}}\dot Wdt~or~W=\dot W\Delta t~as~\Delta t\rightarrow 0$$

The amount of work: path dependent

work: path function$$W=\int_{t_{initial}}^{t_{final}}\delta W$$

$$\delta W: inexact~differential ~of~the~work$$

Mechanisms of work

Mechanical work

Shaft work,$~\delta W=Td\theta$

''Force'': T (torque) 扭力[N*m]

''Displacement'':$~d\theta$

Both are intensive properties

不太算generalized work

Electrical work $$\dot{W_e}=VI$$ V: electrical potential difference

3. Mass flow

mass flow rate, $\dot m~$: 單位時間內有多少質量流經指定的截面積，常用來分析流體。 如果流體密度$~\rho$固定（不可壓縮），則$$\dot m=\rho \dot V=\rho A_c \dot x~(kg/s)$$$$\dot V:~volume~flow~rate;~A_c:~cross-sectional~area;~\dot x:~average~fluid~velocity~normal~to~A_c$$$$Energy~flow~rate:~\dot E=e\dot m~(kJ/s~or~kW)$$

Energy transfer across the boundaries of a system

directional quantities

both magnitude and direction have to be specified

boundary phenomena

recognized only at the boundaries of a system as they across the boundaries

accosiated with process, not a state

unlike properties, no meaning at state

path function

their magnitudes depend on the path followed during a process

Mechanical Energy

$\overset{def}=$the form of the energy that can be converted to mechanical work completely and directly by an ideal mechanical device such as an ideal turbine.

Kinetic energy: $\frac{v^2}2$

Potential energy: $gz$

Flow work: 活塞壓縮液體$\Rightarrow Pv(specific~volume)=\frac{P}{\rho}$

Mechanical energy of a flowing fluid:$$e_{mech}=\frac{P}{\rho}+\frac{v^2}2+gz$$$$\Delta e_{mech}=\frac{P_2-P_1}{\rho}+\frac{v_2^2-v_1^2}2+g(z_2-z_1),~for~incompressible~fluid~(\rho=constant)$$

2.3 First law of thermodynamics- conservation of energy

$$\Delta E_{system}=E_{in}-E_{in}=Q_{in}-Q_{out}+W_{in}-W_{out}+E_{mass~in}-E_{mass~out}$$

In closed system $$\Delta E_{system}=Q_{in}-Q_{out}+W_{in}-W_{out}$$$$=(Q_{in}-Q_{out})-(W_{out}-W_{in})$$$$=Q_{net}-W_{net}$$

For a closed system undergoing a cycle $$E_{initial}=E_{final}$$$$\Rightarrow \Delta E_{system}=0$$$$\Rightarrow Q_{net}=W_{net}$$ Also$$\Delta E_{system}=\dot Q_{net}\Delta t-\dot W_{net}\Delta t$$$$\lim_{\Delta t\rightarrow 0}\frac{\Delta E_{system}}{\Delta t}=\dot Q_{net}-\dot W_{net}=\frac{dE_{system}}{dt}$$

$\frac{dE_{system}}{dt}=0$ steady state 穩態

a closed system undergoing a cycle:$$\dot Q_{net}=\dot W_{net}$$

2.4 Measurement of the internal energy

Q: How do we measure internal energy cycle which is associated with molecular activity

A: choose a stationery system $$\Rightarrow \Delta E=\Delta U$$ by First Law:$$\Delta U=Q(不可量)-W(可量)$$ To define $\Delta U\Rightarrow undergo~a~adiabatic~process$

$$\Rightarrow\Delta U= -W|_{adiabatic}$$

Once have $\Delta U$ ,to evaluate the heat transfer undergoing on an arbitrary process $$Q=\Delta U+W|_{arbitrary}$$

泳池的類比

系統:泳池

下雨:流進熱量

蒸發:流出熱量

人工加水:對系統作功

人工排水:系統對外作功

泳池的體積變化:內能變化

泳池水位:系統溫度以及壓力等intensive properties

2.5 Efficiency

$\eta =\frac{Required~output}{Required~input}$

各種效率:

$\eta_{mech}=\frac{E_{mech,~out}}{E_{mech,~in}}$

總效率combined( or overall) efficiency:

$\eta_{all}=\eta_{turbance}\times\eta_{pump}\times\eta _{thermal}...$

[mechanicalengineerstudyphysics]

並不是使用了科學名詞，或者看來像科學的名詞，就是科學。

[mechanicalengineerstudyphysics]

到底需要多大的能量才能打爆月球？月球的重力結合能（gravitational binding energy）約為

U = 3／5 x G x 月球質量2／月球半徑 = 12 萬 4 千億億億焦耳。

這能量究竟有多巨大呢？太陽每秒鐘釋放的輻射能量約為 382 億億億焦耳。算一算，即是如果把所有太陽光聚焦到月球上  324 秒（即約 5 分半鐘），就能夠毀滅它了。

[mechanicalengineerstudyphysics]

Nissan created self-parking slippers to demonstrate an important point.

[mechanicalengineerstudyphysics]

Tiny robots may one day help keep our bodies in good working order.

[mechanicalengineerstudyphysics]

震動能經由某種形式（猜測是先變轉動能再）轉為電能。

These wind turbines have no blades and produce energy by vibrating.

[mechanicalengineerstudyphysics]

Using long exposure on his camera, PhD candidate David Nadlinger took a photo of an atom illuminated by a laser, while it was suspended in the air by two electrodes. (For a sense of scale, the two electrodes on either side of the atom are 2mm apart). The reason why you’re able to see the atom is because it absorbed and re-emitting the light particles that the laser projected. (David Nadlinger/University of Oxford/EPSRC)

[mechanicalengineerstudyphysics]

[工材]第二週筆記

Phase Diagram 相平衡圖

物質的狀態（state)；相（phase）

$$state~diagram\overset{冷卻和加熱速度慢}{\Rightarrow} equilibrium~diagram\Rightarrow phase~diagram$$

Polymorphism（同質異晶現象）：由化學組成相同的物質，在不同的物理化學條件下形成的不同結構的晶體。

Allotropy（同素異形體）

純金屬的溶解、凝固（solidification）現象

過冷度

低於凝固點還是保持液態的現象

均相成核（homogeneous nucleation）常見的過冷度（差）

樹枝狀結晶方向通常是[111]

晶界

形成是因成核的方向不同

雜質多在此

熔融由此開始

相律

預測的是點、線或面，數量不定。

師曰：「以前這些（八學分）熱力學都教過了云云」

合金種類

純金屬：較少見，如Pb

固溶體$\rightarrow產生畸變$：組成法則$\rightarrow$Hume-Rothery Rule

插入式(inserstitial)：直徑較小的非金屬原子，不規則分佈

置換式(substitutional)

金屬間化合物：如$CuAl_2,~Fe_3C$特性近於非金屬（硬脆、強度大、導電度小）

上述之混合物(mixure)

二元相平衡圖 種類

1. 全率固溶���

Ni-Cu, Au-Ag, Bi-Sb, Ni-Co

Tie line: 與液相線以及固相線相接的等溫線（下圖中的LS線段）

Level rule

偏析(segregation):

非緩慢冷卻下，一層一層冷卻，此結構稱作cored structure（下圖左邊）

phase diagrams by Nurul Adni via SlideShare

一般會均質化處理以提升性能

2. 共晶型（第一類）Eutectic type 1

較type 2少見：Al-Sn, Bi-Cd, Sn-Zn

相當於兩個全率固溶型的圖合併

當$L'_1$冷卻到e點時有下列共晶反應（eutectic reaction）：$$L'_1\rightleftharpoons A(solid)+B(solid)$$

三相共存（液態＋A(solid)+B(solid)）

e點：eutectic point

此溫度：共晶溫度