Notes, summaries, assignments, exams, and problems

Introduction to Computational Fluid Dynamics (CFD)

Definition of CFD: CFD is the process of mathematically predicting physical fluid flow by solving the governing equations using computational power. Every CFD analysis uses a mathematical model and numerical method based on the Navier-Stokes (N-S) equations. Physical properties are calculated based on defined operating conditions.

Main objectives:

• Minimize the cost of the system
• Understanding and comprehension of the problem
• Improve behavior
• Reduce the time and cost of the design stage

3 Fundamental Principles:

1. Mass is conserved
2. F=m*a (Newton's 2nd Law)
3. Energy is conserved

Mass Conservation Principle: The rate of increase of mass in a fluid element equals the net rate of flow of mass into the fluid element.... Continue reading "CFD: Understanding Fluid Flow Through Computational Analysis" »

Understanding the distribution of sample means is crucial in statistics. Let's analyze two distinct scenarios.

MLB Player Salaries in 2012

In 2012, there were 855 major league baseball players. The mean salary was \(\mu = 3.44\) million dollars, with a standard deviation of \(\sigma = 4.70\) million dollars. We will examine random samples of size \(n = 50\) players to understand the distribution of their mean salaries.

Distribution of Sample Means

To describe the shape, center, and spread of the distribution of sample means, we apply the Central Limit Theorem (CLT). The CLT states that for sufficiently large sample sizes (typically \(n \ge 30\)), the sampling distribution of the sample mean will be approximately normal, irrespective of the population... Continue reading "MLB Player Salaries & Dark Chocolate's Vascular Health Impact" »

Understanding Virtualization

Virtualization is the process of creating a virtual (rather than physical) version of something, such as a server, storage device, network resource, or even an operating system. It allows multiple virtual instances to run on a single physical system, increasing efficiency and flexibility by abstracting hardware resources from software environments.

Types of Virtualization Technologies

• Server Virtualization: Dividing a physical server into multiple virtual servers, each with its own OS and applications. Example: Using hypervisors like VMware ESXi, Microsoft Hyper-V, or KVM.
• Desktop Virtualization: Enables users to run a desktop environment from a centralized server. Example: Virtual Desktop Infrastructure (VDI), Citrix,

Threat Actors: Who Are the Attackers?

Threat Vectors: How Attacks Occur

When engaging with the work of others, writers must clearly signal their position regarding the claims being reported. These linguistic resources help establish alignment (agreement) or distance (disagreement/skepticism).

Neutral Projection Language

Neutral Verbal Projection

Used when simply reporting a claim without immediate judgment:

• claim
• propose
• suggest
• indicate
• argue

Neutral Mental Projection

Includes all mental verbs used neutrally (e.g., believe, think).

Resources for Aligning and Distancing

The Second Spanish Republic (1931–1939)

Proclaimed after King Alfonso XIII went into exile.

First president: Niceto Alcalá-Zamora; government led by Manuel Azaña.

Key reforms:

Education: More public, secular, and free schools; aimed to reduce illiteracy.

Church-State separation: Religion removed from schools (secularization).

Women’s rights: Women gained the right to vote in 1933.

Land reform: Attempt to redistribute land from large landowners to poor farmers—slow and controversial.

• Opposition: The Church, army, landowners, and right-wing groups opposed the reforms, increasing social tension.

Main Political Parties

Left-wing:

CNT: Anarchist; anti-state, pro-worker strikes.

PCE: Communist; inspired by the USSR, promoted proletarian dictatorship.... Continue reading "Understanding the Spanish Civil War: A Concise Analysis" »

The aim is to create a single market in the EU where products can move as if there were no borders. This means NO:

• Customs duties between countries
• Hidden charges (CHEEs)
• National rules that make trade harder (MEEs)
• Taxes that discriminate against foreign products

Exceptions are only allowed when they are justified (e.g., health, safety, morality, etc.) and pass the proportionality test.

Prohibition of Tariffs and Charges (Art. 30 TFEU)

Prohibited between Member States:

• Customs duties (aranceles): A monetary charge for crossing a border. Always prohibited, even if small or non-protectionist.
• CHEEs (Charges Having Equivalent Effect): An impuesto disfrazado de otra cosa (tax disguised as something else). A unilateral charge on imports/exports not linked

Washback: Concept and Implications in Language Education

Definition

Washback (or backwash) is the effect that tests have on teaching and learning. It refers to how teachers change their teaching practices and students change their learning strategies in response to a test.

Types of Washback

• Positive Washback: Encourages beneficial practices (e.g., more communicative language teaching).
• Negative Washback: Leads to undesirable outcomes (e.g., teaching to the test, increased stress, ignoring untaught skills).

Who Washback Affects

• Teachers: May adapt content, methods, and assessment styles.
• Students: May focus on test strategies over communication.
• School Authorities: May make curriculum or resource decisions based on test results.
• Educational Systems: Can

Constructing Recombinant DNA

The following steps are involved in the construction of recombinant DNA:

1. Preparation of the Gene: Gene cloning in bacteria is achieved by cleaving DNA with enzymes called restriction endonucleases, which create small fragments. Each fragment often has a "sticky end." Since eukaryotic genes contain introns that are not processed in bacteria, the DNA for cloning is usually obtained from relevant mRNA through the process of reverse transcription. In cases where nucleotide or amino acid sequences are known, synthetic DNA may also be produced.
2. Insertion into a Vector: The vector is a vehicle, such as a plasmid or bacteriophage, used to transfer DNA into a host cell. The vector is cut with the same restriction endonuclease