AMIE Study Circle

What are the causes and effects of stress concentration? Stress concentration is the localized increase in stress that occurs where a material's geometry changes abruptly—such as at holes, notches, fillets, grooves, or sharp corners.  Causes of Stress Concentration Stress concentration is almost always caused by a discontinuity or abrupt change in geometry that interrupts the smooth flow of stress.  Common causes include: Holes and Openings Sharp Corners and Notches Fillets with Small Radi Grooves and Keyways Threads Inclusions and Internal Defects Sudden Changes in Cross-Sectio Surface Roughness and Machining Marks Effects of Stress Concentration  The primary effect is that local stress can be many times higher than the nominal stress, which can lead to: Reduced Static Strength Fatigue Failure Crack Initiation and Propagation Reduced Load Capacity Brittle Fracture in Normally Ductile Materials Warping or Local Yielding What arc the advantages and disadvantages ...

In mining, a safety helmet isn’t a permanent hat—it’s a timed shield. According to DGMS/CMR rules, PPE like footwear and helmets have a statutory shelf life, typically 3–5 years, because UV rays, sweat, and impacts degrade their polymers and shock-absorbing liners. After that date, a helmet that looks fine can shatter like glass under a falling rock. WhatsApp channel: Miners Adda   Yet, many companies treat these expiry dates as suggestions, not laws. They issue a new pair of steel-toed boots only when the old ones literally fall apart, and keep helmets on heads years past their certification. The savings? A few thousand rupees per worker. The cost? A fractured skull or a crushed foot that could have been prevented. In 2022, a drill operator in a Jharkhand mine took a minor blow from a loose rock. His helmet—six years old—cracked clean through, sending plastic shards into his scalp. He survived, but with permanent nerve damage. The company’s internal audit later revealed they’...

MCQ (i) An increase in steam pressure of a boiler during start-up from 4 bar (g) to 12 bar (g), will result in decrease of ____. (a) enthalpy of steam (b) sensible heat of steam (c) specific volume of steam* (d) saturation temperature of steam.

MCQ (i) Following part is not included in Boiler accessories ____. (a) ESP                                                             (b) Economiser (c) Chimney*                                                   (d) Air pre-heater

A wide variety of mining processing and materials-handling equipment is used in underground and surface mining, and in preparation/processing plants with many noise sources on them having a range of varying noise levels. Frequently, a single piece of equipment will combine several individual noise sources.

A steam table gives the properties of water (liquid, vapor, and mixture) at different temperatures and pressures. Common properties listed:   T = Temperature   P = Pressure (absolute, not gauge)   v = Specific volume (m³/kg)   u = Internal energy (kJ/kg)   h = Enthalpy (kJ/kg)   s = Entropy (kJ/kg·K)   x = Quality (mass fraction of vapour, 0 = sat liquid, 1 = sat vapour)

This system is simple in construction and maintenance. It can suit any gradient and curvature of roadways. Even gravity can assist it to the extent that in hilly terrain it could be installed. This type of arrangement, when installed in an incline, it is known as self-acting-incline.