OpenLLM-France/wikimedia huggingface dataset:
# Electronics Handbook/Components/FET/P-channel JFET
## P-channel JFET

P-Channel JFET has a similar construction where N and P regions of N-Channel JFET are swapped.
# Electronics Handbook/Components/Inductors/Parallel Connection

More than one inductors can be connected in series or in parallel to increase or decrease inductance

   ## ${\frac {1}{R_{T}}}={\frac {1}{L_{1}}}+{\frac {1}{L_{2}}}+...+{\frac {1}{L_{n}}}$

When connect two inductors of the same inductance in parallel . The total inductance is halved
# Electronics Handbook/Components/Inductors/Series Configuration
## Series Configuration

More than one inductors can be connected in series to increase inductance

   ### L$_t$ = L$_1$ + L$_2$ + L$_n$

When connect two inductors of the same inductance in series . The total inductance is doubled
# Elementary Spanish/Present Family/Advanced
## Goals

By the end of this lesson, you should be able to ask a strangers about their families and know the names of different sporting activities in Spanish.

## Vocabulary

| Goes to | Va ha |
| Sports | Deportes |
| Soccer | Futbol |
| Baseball | Béisbol |
| Basketball | Basquetbol |
| Track/running | Correr |
| Volleyball | Voleibol |
| Married | Casado/casada |
| Siblings | Hermanos/hermanas |

## Possible questions to ask

| Do you have any kids? | ¿Tiene hijos? |
| My kids go to_____ | Mis hijos/hijas van a _____. |
| Where do your kids go? | ¿Dónde van tus hijos? |
| Do they play any sports? | ¿Juegan deportes tus hijos/hijas? |
| Are you married? | ¿Estás casado/casada? |
| Do you have any siblings? | ¿Tienes hermanos/hermanas? |
Practice with these terms in this interactive exercise: Question practice activity

## Dialogue

In the following dialogue, two strangers meet on the train. Alejandro is learning Spanish and asks Francisco if he could practice his Spanish with him. They converse about their families.
Alejandro: Hola. Mi nombre es Alejandro. Estoy aprendiendo español. ¿Puedo practicar contigo?
Francisco: Mucho gusto Alejandro. Me llamo Francisco. Sí, puedes practicar conmigo.
Alejandro: Mi familia es de Wisconsin. ¿De donde es tu familia?
Francisco: Mi familia es del D.F. en Mejico.
Alejandro: Me encanta la comida Mejicana.
Francisco: Es muy rica.
Alejandro: ¿Estás casado?
Francisco: Sí. Estoy casado.
Alejandro: Yo también estoy casado. ¿Tienes hijos?
Francisco: Sí tengo, dos hijos.
Alejandro: Mi esposa es maestra. ¿Cual escuela van tus hijos?
Francisco: Mis hijos van a P.S. 1002.
Alejandro: ¡Mi esposa enseña ahí! También es entrenadora de beisbol. ¿Juegan deportes tus hijos?
Francisco: ¡Qué mundo tan pequeño! Sí juegan deportes pero no juegan béisbol. Ellos juegan basquetbol. ¿Tienes hijos?
Alejandro: No tenemos hijos.
Francisco: ¿Tienes hermanos?
Alejandro: Sí. Tengo dos hermanas. Ellas viven es Wisconsin.
Francisco: Bueno, este es mi parada. Hablas español muy bien.
Alejandro: Gracias por practicar conmigo.

## Links and Resources

* Picture match activity
* Question practice activity
# Elementary Spanish/Present Jobs/Talking with each other
## Vocabulary

| Own business | Negocio propio |
| Office worker | Trabajador/trabajadora de oficina |
| Small business | Negocio pequeño |
| Big company | Gran empresa |
| Student | Estudiante |
| Restaurant | Restaurante |
| Home maker | Ama de casa |
| Brooklyn | Brooklyn |
| Bronx | Bronx |
| Manhattan | Manhattan |
| Queens | Queens |
| Staten Island | Staten Island |
| Long Island | Long Island |
| Like | Gustar |
| Don’t like | No gustar |
| Comfortable | Cómodo |
| Not comfortable | No cómodo |

### Possible questions for language exchange

| What do you do? | ¿En que trabaja? |
| Where do you work? | ¿Dónde trabaja? |
| How do you like it? | ¿Cómo le gusta? |
Practice with these terms in this interactive exercise:Question practice activity

## Dialogue

Audio lesson activity
Julian: ¿En que trabaja?
Margarita: Trabajo de mi casa. Soy una costurera y hago ropa especial para en cliente.
Julian: ¿Tienes tu propio negocio?
Margarita: Si. Trabajaba para una gran empresa pero no estaba cómoda. Prefiero hacer ropa a la medida para algunos cliente.
Julian: Que bueno.
Margarita: ¿Es que trabaja usted?
Julian: Yo trabajo para un negocio pequeño de papel. Vendemos papel.
Margarita: ¿Cómo te gusta?
Julian: Me gusta muchísimo. Estoy bien cómodo. He trabajado por este negocio por mas de diez años. Mis compañeros del trabajo con como familia.
Margarita: Es bien importante que se lleve bien con su compañeros de trabajo.
Julian: Si. ¿Es por eso que no estabas cómoda en la gran empresa?
Margarita: Si. Mis compañeros del trabajo me hicieron incomoda pero ahora estoy feliz.

## Links and Resources

* Audio lesson activity
* Question practice activity
* Word match activity
# Goals

Welcome to the second unit of the Elementary Spanish guide! Congratulations on your hard work so far.
In these lessons you will learn how to talk about jobs. Like the last unit "Family 1" the material in this unit will will be in the present tense so it will focus on talking about the job you have today or your conversation partner's job.
By the end you will be able to talk about basic kinds of jobs and working environments as well as share your opinions about them.

# Lessons

Just like the last unit, all of these lessons focus on the same topic but each one is focused on the material you need to talk with different groups of people. You should start with the first lessons, "1. Talking with each other", and then proceed to the rest as you have time. The language exchange events will only focus on these "Talking with each other" lessons so no need to worry if you do not have time for the other ones before the next meeting.
* 1. Talking with each other
* 2. Talking with your children
* 3. Talking with acquaintances
# Elementary Spanish/Seasons
## Goals

By the end of this lesson, you will know season words.

## Lesson

Let's begin with some vocabulary building excercises.

### Exercise 1: Picture matching

Picture match activity
This is an interactive lesson where your goal is to select the picture that matches the phrase at the top of the screen. If you click on the wrong picture it will gray out and you can click again to choose another picture. If you want to start the lesson over just reload the page.

### Exercise 2: Audio lesson

[Placeholder for audio lesson activity]
This is an audio lesson. You can either listen online and read the transcript as you go, or you can download the lesson and listen to it on your phone or music player.

### Exercise 3: Example dialogue
#### Synopsis

In the following scene, Siena, AJ and Cate talk about the upcoming and past seasons. Siena seems to be confused due to the temperature. Notice how the use of the word "el" and "la" change according to the different nouns. Use context clues and root words to help you figure out the words "caliente y confundiste."

#### Dialogue

Siena: Esta caliente. ¿Es verano?
AJ: No, todavia no es verano.
Cate: Estamos en la temporada antes de verano.
Siena: O! Estamos en la primavera.
AJ: Te confundiste porque esta mas caliente que el invierno.
Cate: Y también porque las plantas están mas verdes.
Siena: Tienes razón. Las hojas tienen muchas pistas.
AJ: ¡Cuando están morones, rojas y anaranjadas es otoño!
Cate: Ya quiero que sea verano.
Siena, AJ, Cate: ¡NO CLASES!

### Vocabulary words

* Autumn- otoño
* Spring- primavera
* Summer- verano
* Winter- invierno
* After - despues
* Before- antes
* Season - temporada
# Elementary Spanish/Summer
## Goals

By the end of this lesson you will know useful words related to summer.

## Lesson

Let's begin with some vocabulary building excercises.

### Exercise 1: Picture matching

[ Picture match activity]
This is an interactive lesson where your goal is to select the picture that matches the phrase at the top of the screen. If you click on the wrong picture it will gray out and you can click again to choose another picture. If you want to start the lesson over just reload the page.

### Exercise 2: Audio lesson

[Placeholder for audio lesson activity]
This is an audio lesson. You can either listen online and read the transcript as you go, or you can download the lesson and listen to it on your phone or music player.

### Exercise 3: Example dialogue
#### Synopsis

In the following dialogue a mother and her young daughter make summer plans as they head to the hardware store for gardening supplies.
Look out for “muchisimo.” –isimo is added to the “mucho” to mean “a lot.” Try to figure out what “jardin” and “plantas” means by looking for the root word.

#### Dialogue

Hija: ¿Vamos a el parque?
Mamá: No. Ahora vamos a la tienda de detalles para comprar plantas para el jardín.
Hija: ¡Jardineria!
Mama: Si, este verano será precioso. No ocupamos ir al parque para tener un picnic. Lo podemos tener en nuestro jardín.
Hija: Yo tendré muchos excursiones entre las plantas de tomates.
Mama: Con muchísimo cuidado. Las plantas son delicadas.
Hija: Mami! Estoy sudando.
Mama: Ponte este hielo el la frente.
Hija: Gracias mami!

### Vocabulary words

* picnic-picnic
* gardening-jardineria
* vacation-vacaciones
* roadtrip-excursiones
* park- parque
* sweating-sudando
* ice-hielo
* summer-verano
* hardware store – tienda de detalles
# Elementary Spanish/Present Jobs/Talking with acquaintances
## Vocabulary

| Commute | Conmutar |
| Long | Largo |
| Subway | Tren |
| Car | Carro |
| Bus | Autobús |
| Bike | Bicicleta |
| Minutes | Minutos |
| Hours | Horas |
| Traffic | Trafico |
| Transfer | Transferir |
| Get | Conseguir |
| Which | Cual / que |
| How | Como |

### Possible questions for a stranger

| How long have you been there? | ¿Cuánto tiempo estas allí? |
| How do you get to work? | ¿Cómo llegas a tu trabajo? |
| How long does it take you? | ¿Cuánto tiempo duras para llegar? |
| Which ____ do you take? | ¿Qué ____ tomas? |
| What do you do while on the train/bus? | ¿Qué haces cuando estas en el ____? |
Question practice activity

## Dialogues

Erica: Hola. Te veo en este tren todos los días. ¿Vas a trabajar?
Vanessa: Si. Tengo un viaje de una hora cada mañana.
Erica: ¡Yo también! Trabajo en una panadería en el Lower East Side. ¿En que trabajas?
Vanessa: Yo soy una maestra. Trabajo en el Lower East Side tambien.
Erica: ¿A que horas empiezas?
Vanessa: Los niños empiezan a las ocho de la mañana.
Erica: ¡Te gusta llegar al trabajo muy temprano!
Vanessa: Este tren es impredecible. Puedo tomar el cuatro o cinco para ir a trabajar. Ha habido un montón de construcción esta semana pasada. Prefiero llegar al trabajo temprano que tarde.
Erica: Eso tiene sentido. Los niños dependen en ti.
Vanessa: ¡La gente que toma café en esta área también dependen en ti!
Erica: Tienes razón. He trabajado en esta panadería por cinco años y hay gente que viene todo los días que son como familia ya.
Vanessa: ¿Ordenan la misma cosa todo los días?
Erica: Exactamente lo mismo todo los días.
Vanessa: Bueno, esta es mi parada. Ten un buen día.
Erica: Tu también.
* Audio lesson activity

## Links and Resources

* Audio lesson activity
* Word match activity
* Question practice activity
# Elementary Spanish/Present Jobs/Talking with your children
## Vocabulary

| Classroom job | Trabajo de clase |
| Sweeper | Barredor |
| Pass out the papers | Pasador de los papeles |
| Homework organizer | Organizador de las tareas |
| Notebook organizer | Organizador de los cuadernos |
| Calendar | Controlador del Calendario |
| Door | Controlador de la puerta |
| Monitor | Controlador |
| Lights | Luces |
| Art center | Centro de arte |
| Writing center | Centro de escritura |
| Technology | Tecnología |
| Science center | Centro de ciencia |
| Library | Biblioteca |

## Possible questions to ask

In addition to the beginner questions, more possible questions for your child are:
| What is your classroom job? | ¿Qué es tu trabajo de clase? |
| What are your responsibilities? | ¿Qué son tus responsabilidades? |
Practice with these terms in this interactive exercise: Question practice activity

## Dialogue

Audio lesson activity
Cristian: Hola mami.
Patricia: Hola Cristian. ¿Cómo estuvo tu día?
Cristian: ¡Era divertido! Escogimos trabajos de clase hoy. '
Patricia: ¿Qué es tu trabajo de clase?
Cristian: Yo voy hacer el asistente de tecnología.
Patricia: Que chévere. Eso suena muy impresionante.
Cristian: La maestra noto que soy bueno con la tecnología.
Patricia: ¿Qué son tus responsabilidades?
Cristian: Yo voy a ayudar a los niños meterse en sitios educativos en la computadora. ¡Hay niños que no saben usar el ratón pero yo si!
Patricia: ¿Saben como usar en teclado para meterte en sitios educativos?
Cristian: La maestra los hizo fácil. Las paginas están marcadas.
Patricia: Parece que serás un asistente de tecnología exitoso.

## Links and Resoruces

* Audio lesson activity
* Question practice activity
* Word match activity
# Goals

Welcome to the first unit of the Elementary Spanish guide!
In this lesson you will learn how to talk about your family. Most of the material will be in the present tense so it will focus on talking about your family today. Future lessons will cover talking about your family growing up or planning future activity with your family. For this lesson just focus on the present.
By the end you will be able to count to 10, know a dozen words for various family members, and be able to ask and answer some basic questions about your family in conversation with other parents.

# Lessons

All of these lessons focus on the same topic, talking about family, but each one is focused on the material you need to talk with different groups of people: your fellow parents following this guide, your children, and personal acquaintances who already know Spanish.
You should start with the first lessons, "1. Talking with each other", and then proceed to the rest as you have time. The language exchange events will only focus on these "Talking with each other" lessons so no need to worry if you do not have time for the other ones before the next meeting. Each unit will follow this pattern.
* 1. Talking with each other
* 2. Talking with your children
* 3. Talking with acquaintances

# Resources

These are some handy phrases for language students, especially if you begin practicing with acquaintances and native speakers in the community. If you ever get stuck in conversation, these phrases can help smooth everything out and get you back on your conversational feet.

## Helper phrases

| I am learning Spanish. | Estoy aprendiendo español. |
| Can I practice my Spanish with you? | ¿Puedo practicar mi español con tigo? |
| Can you repeat that? | ¿Puede repetir eso? |
| Can you say that slower? | ¿Lo puede decir mas despacio? |
| Thank you for your help. | Gracias por su ayuda. |
If you believe different topics will better help you speak Spanish in the real world, please edit these materials, or post suggestions on the talk page.
# Elementary Spanish/Present Family/Intermediate
## Goals

By the end of this lesson, you should be able to ask and answer questions about family member's birthdays and phone numbers.

## Vocabulary
### People descriptions

| Older | Mayor |
| Younger | Menor |
| Bigger | Más grande |
| Smaller | Más pequeño(a) /chiquito(a) |
| Phone | Teléfono |
| Number | Número |
| Day | Día |
| Month | Mes |
| Year | Año |

### Months of the year

| January | enero |
| February | febrero |
| March | marzo |
| April | abril |
| May | mayo |
| June | junio |
| July | julio |
| August | agosto |
| September | septiembre |
| October | octubre |
| November | noviembre |
| December | diciembre |

### Possible questions to ask your child

| What is your older/younger sister’s/brother’s name? | ¿Cómo se llama tu hermano/hermana mayor/menor? |
| When is your birthday? | ¿Cuándo es tu cumpleaños? |
| When is your sister’s/brother’s birthday? | ¿Cuándo es el cumpleaños de tu hermana/hermano? |
| What is your phone number? | ¿Cuál es tu número de teléfono? |
Practice with these terms in this interactive exercise: Question practice activity

## Dialogue

In the following dialogue, a father has a conversation with his daughter. He is practicing asking questions in Spanish, while his daughter is practicing answering questions in complete sentences. Notice how she turns the questions into complete sentences.
Father: Hola hija.
Daughter: Hola papá. ¿Dónde está mami?
Father: Mami está en la tienda. ¿Cómo se llama tu mamá?
Daughter: Mi mamá se llama Lupe.
Father: ¿Cómo se llama tu hermano mayor?
Daughter: Mi hermano mayor se llama Julián.
Father: ¿Cuántos años tiene Julián?
Daughter: Julián tiene cuatro años.
Father: ¿Cuándo es el cumpleaños de Julián?
Daughter: El cumpleaños de Julián es el cinco de agosto.
Father: ¿Qué año?
Daughter: El dos mil once.
Father: ¿Qué es nuestro número de teléfono?
Daughter: Nuestro número de teléfono es cinco cinco cinco dos tres uno cuatro.
Father: ¡Que bien hablas español!
Podcast activity

## Links and Resources

* Podcast activity
* Word Match Activity
* Question practice activity
# Fundamentals of Transportation/Horizontal Curves/Solution

A given curve was very poorly designed. The two-lane road used has a lower-than-average coefficient of friction (0.05), no superelevation to speak of, and 4-meter lanes. 900 kg vehicles tend to go around this curve and are stylistically top heavy. County engineers have warned that this curve cannot be traversed as safely as other curves in the area, but politicians want to keep the speed up to boost tourism in the area. The curves have a radius of 500 meters and a design speed of 80 km/hr. Because the vehicles using the curve are top heavy, they have a tendency to roll over if too much side force is exerted on them (the local kids often race around the curve at night to get the thrill of "two-wheeling"). As an engineer, you need to prove that this curve is infeasible before an accident occurs. How can you show this?
The stated speed is 80 km/hr. The easiest way would be to prove that this is too high. We will look at the innermost lane, since forces will be greater there. Using the general curve radius formula and solving for v, we find:
$R={\frac {v^{2}}{g\left({e+f_{s}}\right)}}={\frac {v^{2}}{9.8\left({0.05+0}\right)}}=500-(4/2)\,\!$
$v=15.62\ m/s=56.23\ km/hr\,\!$
80 km/hr is much greater than 56.23 km/hr, which by default means that more force is being exerted on the vehicle than the road can counter. Thus, the curve's speed limit is dangerous and needs to be changed.
# Fundamentals of Transportation/Modal Split

This page describes historical, but no longer standard, practice in Mode Choice models.
The early transportation planning model developed by the Chicago Area Transportation Study (CATS) focused on transit, it wanted to know how much travel would continue by transit. The CATS divided transit trips into two classes: trips to the CBD (mainly by subway/elevated transit, express buses, and commuter trains) and other (mainly on the local bus system). For the latter, increases in auto ownership and use were trade off against bus use; trend data were used. CBD travel was analyzed using historic mode choice data together with projections of CBD land uses. Somewhat similar techniques were used in many studies. Two decades after CATS, for example, the London study followed essentially the same procedure, but first dividing trips into those made in inner part of the city and those in the outer part. This procedure was followed because it was thought that income (resulting in the purchase and use of automobiles) drove mode choice.

## Diversion Curve techniques

The CATS had diversion curve techniques available and used them for some tasks. At first, the CATS studied the diversion of auto traffic from streets and arterial to proposed expressways. Diversion curves were also used as bypasses were built around cities to establish what percentage of the traffic would use the bypass. The mode choice version of diversion curve analysis proceeds this way: one forms a ratio, say:
    ${\frac {c_{transit}}{c_{auto}}}=R\,\!$
where:
    c$_m$ = travel time by mode m and
    R is empirical data in the form:
Given the R that we have calculated, the graph tells us the percent of users in the market that will choose transit. A variation on the technique is to use costs rather than time in the diversion ratio. The decision to use a time or cost ratio turns on the problem at hand. Transit agencies developed diversion curves for different kinds of situations, so variables like income and population density entered implicitly.
Diversion curves are based on empirical observations, and their improvement has resulted from better (more and more pointed) data. Curves are available for many markets. It is not difficult to obtain data and array results. Expansion of transit has motivated data development by operators and planners. Yacov Zahavi's UMOT studies contain many examples of diversion curves.
In a sense, diversion curve analysis is expert system analysis. Planners could "eyeball" neighborhoods and estimate transit ridership by routes and time of day. Instead, diversion is observed empirically and charts can be drawn.
# Fundamentals of Transportation/Mode Choice/Additional Problems
## Additional Questions

* What factors determine mode choice, utility $U_{mij}$
* What role does socio-economics play in mode choice?
* What is an aggregate model, disaggregate model?
* How is probability ($P_{m}$) calculated?
* What happens to probability when utility increases or decreases?
* Why is it hard for transportation engineers to determine how many people will be taking one mode?
* Who developed the logit model for transportation mode choice?
* What is “kiss and ride”
* What happens when a new mode is introduced?
* Explain the red bus/blue bus paradox, and Independence of Irrelevant Alternatives feature of multinomial logit models.
* Compare the logit model with the gravity model.
* What is an alternative specific constant?
# Fundamentals of Transportation/Mode Choice/Homework
## Homework

1. Identify five independent variables that you believe affect mode choice. Pose hypotheses about how each variable affects share of travel by each mode.
2. Explain Independence from Irrelevant Alternatives
3. You are given the following mode choice model.
$U_{ij}=-2C_{ijm}+5D_{T}-5D_{W}$
Where: $C_{ijm}=$ travel time between i and j by mode m
$D_{T}=$ dummy variable (alternative specific constant) for transit
$D_{W}=$ dummy variable (alternative specific constant) for walking
Here auto is assumed the baseline mode.
The auto travel time between zones (in minutes) is given by the following matrix:
| Origin \ Destination | To Dakotopolis | To New Fargo |
| From Dakotopolis | 5 | 9 |
| From New Fargo | 9 | 4 |
The transit travel time between zones (in minutes) is given by the following matrix:
| Origin \ Destination | To Dakotopolis | To New Fargo |
| From Dakotopolis | 10 | 15 |
| From New Fargo | 15 | 8 |
The walk travel time between zones (in minutes) is given by the following matrix:
| Origin \ Destination | To Dakotopolis | To New Fargo |
| From Dakotopolis | 10 | 30 |
| From New Fargo | 30 | 10 |
Using a logit model, what is the probability of a traveler taking transit?
# Fundamentals of Transportation/Mode Choice/Problem2

Prior to the collapse, there were two modes serving the Marcytown-Rivertown corridor: driving alone (d) and carpool (c), which takes advantage of an uncongested carpool lane. The utilities of the modes are as given below.
$U_{d}=-t_{d}\,\!$
$U_{c}=-12-t_{c}\,\!$
where t is the travel time
Assuming a multinomial logit model, and
A) That the congested time by driving alone was 15 minutes and time by carpool was 5 minutes. What was the modeshare prior to the collapse?
B) How would you interpret the constant of -12 in the expression for Uc?
C) After the collapse, because of a shift in travelers from other bridges, the travel time by both modes increased by 12 minutes. What is the post-collapse modeshare?