Notes, summaries, assignments, exams, and problems

Tunnel Lining Fundamentals

Purpose of Tunnel Lining

• Support tunnel structure.
• Prevent water ingress.
• Improve durability.

Types of Tunnel Lining

• Concrete
• Shotcrete
• Steel
• Masonry

Sections of Tunnel Lining

• Crown: Top of the tunnel.
• Inverts: Bottom of the tunnel.
• Walls: Sides of the tunnel.

Types of Foundation Footings

• Spread Footing (Pad footing) – Supports a single column.
• Strip Footing (Continuous footing) – Continuous foundation beneath a wall.
• Raft Foundation – Covers the entire building footprint; distributes load on weak soils.

Understanding Foundation Settlement

• Definition: Downward movement due to soil compression.
• Notes:
  • Coarse soils: Settlement often ≤ 25 mm (rarely > 50 mm).
  • Loose sands below water table: More settlement.
  • Clay: Consolidation settlement,

Biology Class IX: Tissues Assessment

A. Choose the Correct Option (1x5=5)

1. Rapid elongation of bamboo stem is due to:

   • a. Lateral meristem
   • b. Intercalary meristem
   • c. Cambium
   • d. None of the above

2. Which of the following tissues has dead cells?

   • a. Parenchyma
   • b. Sclerenchyma
   • c. Collenchyma
   • d. Epithelial tissue

3. Girth of stem increases due to which of the following meristem?

   • a. Apical
   • b. Intercalary
   • c. Lateral
   • d. None of the above

4. The flexibility in plants is due to a tissue called:

   • a. Chlorenchyma
   • b. Parenchyma
   • c. Sclerenchyma
   • d. Collenchyma

5. Which of the following tissues has the ability to divide?

   • a. Xylem
   • b. Phloem
   • c. Meristematic tissue
   • d. Permanent tissue

B. Very Short Type Questions (2x2=4)

1. Define the following:

   • a. Tissue
   • b. Differentiation

2. Write any two utilities of tissue.

Day 1: Python Basics for AI/ML Preparation

Output Statements

• print() – Displays output to the console.
• end=" " – Prevents a new line after the print statement.
• sep="," – Specifies the character used to separate multiple items in the output.

Input and Type Casting

• The input() function always returns a string data type.
• Adding strings results in *concatenation* (e.g., "5" + "10" = "510").
• Use int() or float() for numerical input conversion:

  Example: num = int(input("Enter a number: "))

Variables and Data Types

• Common types include int (integer), float (decimal), str (string), and bool (boolean).
• Use type(variable) to check the data type of any variable.

Formatted Strings (f-Strings)

• Used for easy string formatting and embedding variables:

  Example: print(

E-commerce Security Requirements

E-commerce security refers to the protection of e-commerce assets from unauthorized access, use, alteration, or destruction. Because financial transactions and sensitive information (like credit card numbers, passwords, and personal details) are involved, strong security is essential in e-commerce systems.

Key E-commerce Security Requirements:

• Authentication: Ensures that the parties involved (both buyer and seller) are who they claim to be.
• Authorization: Grants specific permissions to authenticated users.
• Confidentiality: Ensures that data is accessible only to authorized individuals.
• Integrity: Ensures that data is not altered during transmission or storage.
• Non-Repudiation: Prevents parties from denying their actions.

What is Information Security?

Information security means protecting data from theft, alteration, destruction, disclosure, or denial of access. It has traditionally relied on physical measures (e.g., locked cabinets) and administrative controls (e.g., personnel screening). Even today, some reliance on physical security remains.

Modern Information Security Needs

With increased computer usage, automated tools are now essential for protecting stored information. As network usage grows, securing data during transmission has become equally essential.

Aspects of Information Security (ITU-T X.800/1205)

• Security Attack: Any action that compromises system security.
• Threat: A potential violation, defined as capability plus intent.
• Security Mechanism: Any policy

Defining Creams and Pastes

Creams

Creams are semi-solid emulsions used externally on the skin. They can be either oil-in-water (O/W) or water-in-oil (W/O) emulsions. They are used for moisturizing, healing, or delivering drugs through the skin.

• Example: Cold Cream (W/O), Vanishing Cream (O/W)

Pastes

Pastes are also semi-solid but contain a high amount of insoluble powders (around 25-50%), making them stiffer and more absorptive. They form a protective layer on the skin and are used where longer contact is needed.

• Example: Zinc Oxide Paste

Understanding Pharmaceutical Aerosols

Aerosols are pressurized dosage forms that release active ingredients as a fine spray, mist, or foam when a valve is opened. They use propellants (like hydrocarbons or compressed... Continue reading "Pharmaceutical Dosage Forms: Creams, Powders, and Solutions" »

1. Understanding Arrays and Their Types

An array is a collection of elements of the same data type stored in contiguous memory locations. It is used to store multiple values in a single variable and can be accessed using index numbers. The indexing in an array starts from 0. Arrays help manage and process data efficiently, especially when dealing with large volumes of similar data.

Types of Arrays Based on Dimensions

1. One-Dimensional Array: It stores data in a linear list format.
2. Multi-Dimensional Array: It stores data in matrix form (like 2D, 3D arrays), which is useful in applications like image processing and tables.

Types of Arrays Based on Memory Allocation

1. Static Array: The size of the array is fixed at compile-time. Memory is allocated when

The shoulder joint, also known as the glenohumeral joint, is a ball-and-socket type synovial joint that allows a wide range of motion in the upper limb. Here’s a breakdown of its key features:

🦴 Bones Involved

1. Humerus – the upper arm bone; its head forms the "ball."
2. Scapula (shoulder blade) – contains the glenoid cavity, which forms the "socket."
3. Clavicle (collarbone) – indirectly involved, connecting the shoulder to the axial skeleton via the acromioclavicular and sternoclavicular joints.

🦾 Movements Allowed

Because it is a ball-and-socket joint, it allows:

• Flexion and Extension
• Abduction and Adduction
• Medial (internal) and Lateral (external) Rotation
• Circumduction (circular movement)

💪 Muscles Involved

Key muscles acting on the shoulder... Continue reading "Shoulder Joint Anatomy: Bones, Muscles, Movement, & Injuries" »

World War II: Major Combatants & Events

Sides and Leaders of WWII

• Allied Powers:
  • Countries: U.S., U.K., France, China, Soviet Union
  • Leaders: Winston Churchill (U.K.), Franklin D. Roosevelt / Harry S. Truman (U.S.), Joseph Stalin (Soviet Union), Charles de Gaulle (France), Chiang Kai-shek (China)
• Axis Powers:
  • Countries: Germany, Japan, Italy
  • Leaders: Adolf Hitler (Germany), Benito Mussolini (Italy), Emperor Hirohito / Hideki Tojo (Japan)

Molotov-Ribbentrop Pact (1939)

Signed in 1939 by Germany and the Soviet Union, this pact included a secret protocol that divided territories:

• Germany: Western Poland and part of Lithuania
• Soviet Union: Eastern Poland, Finland, Estonia, Latvia, and parts of Romania

Nuclear Bombings of Japan (1945)

Hiroshima was bombed... Continue reading "Major World Conflicts and Historical Turning Points" »

AdaBoost: Adaptive Boosting Explained

AdaBoost is one of the simplest and earliest boosting algorithms. The main idea behind AdaBoost is to combine many weak learners (models that do slightly better than random guessing) into one strong learner.

It works by training multiple models one after another. After each model, the algorithm checks which data points were predicted wrong. It then gives more importance (weight) to those wrongly predicted samples so that the next model focuses more on correcting those mistakes.

Each new model tries to fix the errors made by the previous ones. At the end, all models are combined using weighted voting to make the final prediction. This helps improve accuracy and reduces errors.

Key Characteristics of AdaBoost

• Combines