Notes, summaries, assignments, exams, and problems for University

Essential Chemistry Formulas and Reference

Miscellaneous Formulas

• Area of a Circle: 3.14r²
• Volume: Area × Height
• Density: Mass / Volume
• % Composition of Element: [(# of atoms of element) × (atomic weight of element)] / formula weight of substance × 100
• Molarity: (moles of solute) / (volume of solution in Liters)
• Bond Order: (# shared electrons) - (# nonbonding electrons) / 2
• Pressure: Force / Area
• Pressure × Volume: nRT
• Density of Gas: (Pressure × Molar Mass) / (R × Temperature)
• Molarity of Gas: (Density × R × Temperature) / Pressure

Temperature and Chemical Conversions

• Celsius to Kelvin: K = C + 273.15
• Kelvin to Celsius: C = K - 273.15
• Celsius to Fahrenheit: F = 9/5(C) + 32
• Fahrenheit to Celsius: C = 5/9(F - 32)
• 1 amu: 1.66054 × 10⁻²⁴ g
• Grams

Linux File System Structure: An archive of Linux is associated with 3 parts: superblock, inode table, and data blocks.

Network Ports: To see the ports assigned to services.

Display Active TCP/IP Connections: netstat -a

User Management:

• Create password: passwd (user)
• Add user to group: usermod -g group_name
• Disable: 60001
• Enable: 60002

Practical Commands:

Add User: adduser

1. Change folder privileges: chmod
2. Check privileges: ls -de (see if you changed privileges)

1. Create a user: useradd newuser
passwd newuser
2. Create a directory: The command mkdir is used to create directories:
   mkdir mydirectory
3. Create a report: ps -aux >> reporte.txt
4. Directories associated with the user: -d dirname
5. Changing permission: chmod 744 file.txt /file.txt
6. Change owner: chown
   Entering

Monopoly vs. Perfect Competition

The main differences between a monopolist and a competitive firm are that in the case of a monopoly, there is greater scope for establishing the price, although this control is not absolute. The monopoly firm has more freedom to adjust both the price and the quantity produced in their attempt to maximize profits.

Social Impact and Price Discrimination

From society's point of view, a monopoly involves less desirable effects than those derived from economic competition. In general, a monopoly results in lower production of goods and services than would result under competitive conditions, often with higher prices. Another common practice of a monopoly is price discrimination, which involves charging different prices... Continue reading "Monopoly vs. Perfect Competition: Key Market Differences" »

To control by PWM requires 2 factors:

1-crossing detection signal by 0.

2-? determine the time, every time you walk by 0.

to detect the zero crossing can be performed
through an operational amplifier connected
comparator.

TCA = 785

Pin Symbol Function

1 GND Earth

2 Q2 *Output 2 Inverted

3 Output U QU

4 Q1 * Output 1 Inverted

5 5Synchronizing voltage Vsync (to detect

zero crossing)

6 Inhibitor

7 QZ Z Output

8 8 Vref voltage stabilized (continuous signal for the

integrator)

9 9 ramp resistor R9 (for the integrator)

10 C10 ramp Capacitance (for the integrator)

11 11 V11 Control Voltage (for comparator)

12 12 C12 pulse Extension

13 LLong pulse

14 Q1 Output 1

15 Q2 Output 2

16 l sSupply voltage.

Verb Tenses

Present Continuous vs. Present Simple

1. I'm angry with William. I am not talking / don't talk to him.

2. Listen! My sister is singing / sings in the shower.

3. This cheese tastes / is tasting strange.

4. Are you thinking / Do you think Ann is pretty?

5. Laura is walking / walks to school every day.

Past Simple vs. Past Continuous

1. The sun SETS (set) in the west.

2. Please don't disturb me. I AM STUDYING (study).

3. I still DON’T KNOW (not know) the answer.

4. DO YOU ALWAYS GO (you / always /go) to the cinema on Friday nights?

5. We HAVE (have) a picnic next Sunday.

Present Simple vs. Present Continuous

6. How much DOES THIS PARCEL WEIGH (this parcel / weigh)?

7. Ms Rivers is busy at the moment. She IS TEACHING (teach).

8. Now I REMEMBER (remember)... Continue reading "Jamie Oliver: A Culinary Icon" »

Inventory Management

Safety Stock: The amount of inventory carried in addition to the expected demand.

Stock Keeping Unit (SKU): A common term used to identify an inventory item.

Material Requirements Planning (MRP)

Available to Promise: A feature of MRP systems that identifies the difference between the number of units currently included in the master schedule and actual (firm) customer orders.

Bill of Materials (BOM): A computer file that contains the complete product description, listing the materials, parts, and components, and the sequence in which the product is created.

Closed-loop MRP: The use of actual data from the production system to continually update the MRP system. This feedback is provided so that planning can be kept valid at all... Continue reading "Key Terms in Production and Inventory Management" »

The Waste Land by T.S. Eliot

1. Sections and Summaries

This poem comprises five sections:

• The Burial of the Dead

  Part I conveys a sense of apprehension and incomprehension among various characters in different situations. Madame Sosostris, a fortune-teller, adds to the confusion with enigmatic pronouncements that only gain clarity later in the poem. The city, particularly London, is depicted as a grim place inhabited by people unable to live fully or escape their deadness.

• A Game of Chess

  Part II presents two scenes showcasing the desolation of people's lives. The first depicts a richly decorated room where a wealthy lady's constant questions reveal her anxiety and lack of control. The second scene unfolds in a London pub, where two women discuss

Project-Based Learning in Content-Based Classrooms

Project work has been integrated into content-based classrooms to foster a student community of inquiry. This approach emphasizes authentic communication, cooperative learning, collaboration, and problem-solving.

Project Work as an Extension of Instruction

Content-based instruction allows for the natural integration of sound language-teaching practices. While some professionals equate project work with simple group work or task-based activities, it represents a more comprehensive framework. Project-based learning should be viewed as a method to integrate language and content learning effectively.

Primary Characteristics of Project Work

• Content-Focused: Real-world subject matter and topics of interest

Role of the Teacher

• Facilitator: Guides learning / Guía el aprendizaje
• Fosters autonomy: Fomenta autonomía
• Student-centered classes
• Scaffolding and positive feedback
• Avoids pressure: Evita presión y juicios negativos

Classroom Management

• Maintain order and attention
• Clear routines
• Attention-grabbers
• Change activities every 15–20 minutes
• Use of different spaces
• Positive reinforcement and autonomy

Communicative Language Teaching

• Communicative approach: Enfoque comunicativo
• Meaningful language: Lenguaje con significado
• Real-life situations
• Use of language to communicate

4 Dimensions of Communicative Competence

1. Linguistic: Vocabulario, gramática, sintaxis
2. Sociolinguistic: Normas sociales, cultura
3. Discourse: Cohesión y coherencia
4. Strategic: Compensar fallos, estrategias

React Hooks and Essential Libraries

useState Hook

Purpose

Purpose: Adds state to functional components.

Import

import { useState } from 'react';

Syntax

const [state, setState] = useState(initialValue);

Update Methods

• setState(newValue);
• setState(prevState => ...); (for updates based on previous state)

Example

import React, { useState } from 'react';

function Counter() {
  const [count, setCount] = useState(0);

  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={() => setCount(count + 1)}>Increment</button>
    </div>
  );
}

useEffect Hook

Purpose

Purpose: Performs side effects such as data fetching, subscriptions, or direct DOM manipulations.

Import

import { useEffect } from 'react';

Syntax

useEffect(