10+ NDMC Interview Questions and Answers

I troubleshoot mechanical systems by identifying the root cause, analyzing data, testing components, and implementing solutions.

• Identify the symptoms of the problem and gather relevant data

• Analyze the data to pinpoint the root cause of the issue

• Test individual components to determine if they are functioning properly

• Implement solutions based on findings, such as repairing or replacing faulty parts

• Document the troubleshooting process and any solutions implemented

Design parameters for heat exchangers include heat transfer rate, pressure drop, material selection, and flow arrangement.

• Heat transfer rate: determines the efficiency of the heat exchanger

• Pressure drop: affects the flow rate and energy consumption

• Material selection: depends on the fluid properties and operating conditions

• Flow arrangement: affects the heat transfer rate and pressure drop

Different types of heat transfer include conduction, convection, and radiation, each governed by specific equations.

• Conduction: Heat transfer through a material without any movement of the material itself. Governed by Fourier's Law of Heat Conduction.

• Convection: Heat transfer through a fluid (liquid or gas) due to the movement of the fluid. Governed by Newton's Law of Cooling.

• Radiation: Heat transfer through electromagnetic waves. Governed by Stefan-Boltzmann Law and Wien's D...read more

Tube OD selection depends on factors such as fluid flow rate, pressure, and material compatibility.

• Consider fluid flow rate and pressure to determine appropriate tube OD

• Ensure compatibility of tube material with fluid being transported

• Consult industry standards and guidelines for recommended tube OD sizes

• Factor in any space constraints or installation requirements

• Perform testing and analysis to verify tube OD selection

Pump selection depends on the fluid properties, flow rate, head, and system requirements.

• Determine the fluid properties such as viscosity, density, and corrosiveness.

• Calculate the required flow rate and head based on the system requirements.

• Consider the pump type such as centrifugal, positive displacement, or axial flow.

• Choose the appropriate pump size and material based on the fluid properties and system requirements.

• Evaluate the pump efficiency and power consumption.

• Example...read more

Different types of boilers include fire tube boilers, water tube boilers, and electric boilers.

• Fire tube boilers have hot gases flowing through tubes that are surrounded by water

• Water tube boilers have water flowing through tubes that are heated by hot gases

• Electric boilers use electricity to generate heat instead of burning fuel

Types of welding include MIG, TIG, stick, and flux-cored welding.

• MIG welding (Metal Inert Gas) uses a wire electrode and shielding gas to join metal.

• TIG welding (Tungsten Inert Gas) uses a tungsten electrode and filler rod with shielding gas.

• Stick welding (Shielded Metal Arc Welding) uses a flux-coated electrode to create the weld.

• Flux-cored welding uses a tubular wire electrode with flux inside to shield the weld.

Different types of welding defects include porosity, undercutting, incomplete fusion, and cracks.

• Porosity: caused by gas entrapment during the welding process, resulting in small holes in the weld metal.

• Undercutting: occurs when the base metal is melted away from the weld, creating a groove along the weld toe.

• Incomplete fusion: happens when the weld metal does not properly fuse with the base metal, leading to weak joints.

• Cracks: can occur due to excessive stress, improper coo...read more

Acceptance criteria for RT & PT

• RT acceptance criteria may include verifying that the system meets real-time performance requirements

• PT acceptance criteria may involve ensuring that the system passes performance testing benchmarks

• Examples: RT criteria could be response time < 100ms, PT criteria could be handling 1000 concurrent users without crashing

Material of construction refers to the type of material used to build a structure or object.

• Material of construction can impact the durability, strength, and cost of a project.

• Common materials include steel, concrete, wood, and plastic.

• The choice of material depends on factors such as the intended use, budget, and environmental conditions.

• For example, steel is often used in high-rise buildings for its strength, while wood is commonly used in residential construction for its c...read more

Types of heat transfer include conduction, convection, and radiation.

• Conduction: Heat transfer through direct contact between particles, such as a metal spoon heating up in a hot drink.

• Convection: Heat transfer through the movement of fluids, such as boiling water in a pot.

• Radiation: Heat transfer through electromagnetic waves, such as the sun warming the Earth.

Heat transfer in a tea cup involves conduction from the hot liquid to the cup, convection as the liquid circulates, and radiation from the cup to the surroundings.

• Conduction: Heat is transferred from the hot tea to the cup through direct contact.

• Convection: As the tea circulates in the cup, heat is distributed throughout.

• Radiation: The cup emits heat to the surroundings, cooling down the tea.

• Material of the cup affects heat transfer rate.

• Stirring the tea enhances convection a...read more

The fabrication procedure of a heat exchanger involves designing, assembling, and welding together various components to create a system for transferring heat between two fluids.

• Designing the layout and dimensions of the heat exchanger based on the specific requirements and operating conditions

• Selecting the appropriate materials for the heat exchanger components to ensure compatibility with the fluids and temperature ranges

• Assembling the components such as tubes, fins, header...read more