Siemens Energy Control System Engineer Interview Questions and Answers

Node.js is a runtime environment that allows you to run JavaScript code outside of a web browser.

• Node.js is built on Chrome's V8 JavaScript engine.

• It uses an event-driven, non-blocking I/O model.

• Node.js is commonly used for building server-side applications.

• It has a large ecosystem of open-source libraries and frameworks like Express.js.

Event loop is a mechanism that allows a program to efficiently handle multiple events or tasks concurrently.

• Event loop is commonly used in asynchronous programming to manage tasks that may take varying amounts of time to complete.

• It continuously checks for events or tasks in a queue and executes them one by one.

• Event loop helps prevent blocking of the main thread by allowing non-blocking execution of tasks.

• Popular exam...read more

Callback is a function passed as an argument to another function to be executed later, while a promise is an object representing the eventual completion or failure of an asynchronous operation.

• Callback is used in traditional asynchronous programming, while promises are used in modern asynchronous programming.

• Callbacks can lead to callback hell or pyramid of doom, while promises provide better readability and error hand...read more

Middlewares in Node.js are functions that have access to the request and response objects, and can modify or terminate the request-response cycle.

• Middlewares are functions that are executed in the middle of the request-response cycle.

• They can perform tasks like parsing request data, logging, authentication, etc.

• Middlewares can be added using app.use() method in Express framework.

• Example: app.use(bodyParser.json()) to p

Event emitter is a pattern used to handle and respond to events in software development.

• Event emitter is a design pattern commonly used in Node.js for handling events.

• It allows objects to subscribe to events and be notified when those events occur.

• Event emitter is often used for asynchronous programming and decoupling components.

• Example: EventEmitter class in Node.js can be used to create custom events and handle them.

The standard dimensions of a brick are 3 5/8 inches x 2 1/4 inches x 8 inches.

• Standard brick size is 3 5/8 inches x 2 1/4 inches x 8 inches

• Bricks can also come in different sizes based on region or purpose

• Common brick sizes include modular, jumbo, and queen

The water-cement ratio is the ratio of the weight of water to the weight of cement used in a concrete mix.

• It is a crucial factor in determining the strength and durability of concrete.

• A lower water-cement ratio results in stronger and more durable concrete.

• The typical range for water-cement ratio is between 0.4 to 0.6.

• Excessive water in the mix can lead to lower strength and durability of concrete.

Heat of hydration is the heat released when water is added to cement during the chemical reaction of hydration.

• Heat of hydration is the heat released when water is added to cement during the chemical reaction of hydration.

• It is an exothermic reaction, meaning it releases heat.

• The heat of hydration is important to consider in concrete construction to prevent cracking and ensure proper curing.

• Higher heat of hydration can...read more

Curing is the process of maintaining adequate moisture and temperature in concrete to ensure proper hydration and strength development.

• Curing helps prevent cracking and ensures the concrete reaches its full strength potential.

• Common curing methods include water curing, membrane curing, and curing compounds.

• Proper curing typically lasts for at least 7 days, but can vary depending on the type of concrete mix and environm

Footing is the bottommost part of a foundation that distributes the load of the structure to the soil.

• Footing is typically made of concrete and is wider than the foundation walls to provide stability.

• Foundations are the lower portion of a building structure that transfers the load to the soil.

• There are different types of foundations such as shallow foundations (like spread footings) and deep foundations (like piles).

One way slab is supported on two opposite sides while two way slab is supported on all four sides.

• One way slab is designed to carry loads along one direction only

• Two way slab is designed to carry loads along both directions

• One way slab is supported on two opposite sides

• Two way slab is supported on all four sides

Concrete grades are classifications that indicate the strength of the concrete mix used in construction.

• Concrete grades are denoted by the letter 'M' followed by a number, such as M20, M30, etc.

• The number after 'M' represents the compressive strength of concrete in N/mm^2 after 28 days of curing.

• Higher grade numbers indicate higher strength concrete, suitable for different types of construction projects.

• For example, M2...read more

Concrete strength typically reaches about 70-80% of its final strength after 7 days.

• Concrete strength gain after 7 days is usually around 70-80% of its final strength

• Factors such as mix design, curing conditions, and type of cement can affect the rate of strength gain

• For example, high early strength concrete may reach higher percentages of its final strength after 7 days compared to normal concrete

Non destructive testing of concrete is a method used to evaluate the properties of concrete without causing damage.

• Methods include ultrasonic testing, rebound hammer, and ground penetrating radar.

• These tests help assess the strength, durability, and quality of concrete structures.

• Non destructive testing is essential for ensuring the safety and longevity of buildings and infrastructure.

• Examples of non destructive testin...read more

Transportation of concrete involves mixing, loading, and delivering the concrete to the construction site.

• Concrete is mixed at a batching plant using cement, sand, gravel, and water.

• The mixed concrete is then loaded into transit mixers or concrete trucks for transportation.

• Transit mixers rotate to prevent the concrete from setting during transportation.

• Concrete pumps can also be used to transport concrete to hard-to-re

Admixtures are used in ready mixed concrete to improve workability, durability, and strength.

• Admixtures help in reducing water content while maintaining workability.

• They enhance the durability of concrete by reducing permeability and increasing resistance to chemicals.

• Admixtures can also accelerate or retard the setting time of concrete.

• Examples of admixtures include water reducers, accelerators, retarders, and air-ent