Bissoy.com
Doctors Medicines MCQs Q&A

The porous-metal bearings are used where re-lubrication is difficult.

The porous-metal bearings are used where re-lubrication is difficult. Correct Answer True

Most porous-metal bearings are made of either bronze or iron, with 10 to 35 vol% interconnected voids or porosity. In operation, lubricating oil stored in these pores feed the bearing surface through these interconnected pores, when the temperature increases during operation. Any oil, which is forced from the loaded zone of the bearing, is later reabsorbed by the pores through capillary action. Since these bearings can operate for long periods of time without additional supply of lubricant, they are convenient to be used where re-lubrication is difficult.

Related Questions

Consider the following statements in connection with thrust bearings: 1) Cylindrical thrust bearings have higher coefficient of friction than ball thrust bearings. 2) Taper rollers cannot be employed for thrust bearings. 3) Double-row thrust ball bearing is not possible 4) Lower race, outer race and retainer are readily separable in thrust bearings. Which of the above statements are correct?
Ball bearings are preferred over other types of bearings for machines rated up to 75 kW. Which of the following is not true for ball bearings?
The question below consists of a statement followed by two assumptions numbered I and II. An assumption is something supposed or taken for granted. You have to consider the statement and the following assumptions and decide which of the assumptions is implicit in the statement. You have to consider the statements to be true even if they seem to be at variance from commonly known facts. Statement: Although the exam was difficult, students managed to pass. Assumptions: I. Students generally don’t pass difficult exams. II. Difficult exams don’t let students excel.
In the following question, sentences of a paragraph have been jumbled and labeled as P, Q, R, and S. You are required to rearrange the jumbled sentences of the paragraph and mark your response accordingly by selecting the correct option. S1: There's nothing new in the idea that adolescence is a difficult period for everyone the adolescents themselves, of course, as well as for their parents P. Quite simply, the two generations live worlds apart. Now, psychologists are beginning to understand the biological basis for this eternal conflict. Q. Teenagers' brains really are different from those of their parents and a fully adult brain may not develop until well after the teenage years. R. For their parts, adolescents can't understand what their parents are worried about; they find their tastes and responsible concerns boring and outdated S. From an adult point of view, adolescents are difficult, rebellious, irresponsible, often selfish, and self-absorbed, prone to dangerous behaviour that risks their health, their life, and their possibility of future happiness. S6: This new knowledge, it is hoped, will help all of us deal better with the difficult and often painful years of transition from childhood to adulthood.
What type of bearing is used for main bearings and connecting rod bearings?
How many guide bearings are used along with the simple thrust bearings to pick up radial loads?
The type of bearing most commonly used for main bearings and connecting rod bearings is
Read the passage carefully and choose the best answer to each question out of the four alternatives and click the button corresponding to it.
Modern civilization is completely dependent on energy, which has therefore to be abundant and also economical. About 85% of the world's energy is supplied by oil, coal and natural gas while nuclear, hydro, wind and solar power and biomass supply the rest. Coal, nuclear and hydro are used primarily to generate electricity while natural gas is widely used for heating. Biomass is used both for heating and cooking. The wind and solar power is the future's hope as they are sustainable energy sources. Oil powers almost all machines that move and that makes oil uniquely versatile. Oil powered airplanes carry 500 people across the widest oceans at nearly the speed of sound. Oil powered machines produce and transport food. Oil powered machines are ubiquitous. Clearly, we live in the age of oil but it is drawing to a close. According to data available if oil production remains constant until it's gone, there is enough to last 42 years. Oil wells will produce less as they become depleted, which will make it impossible to keep production constant. Similarly natural gas and coal will last another 61 years and 133 years respectively. Naturally, as they become scarce, they become expensive, leading to a worldwide energy crisis. If we are to survive on this planet, we have to make a transition to sustainable energy sources. The transition may be willy-nilly or planned - the choice is ours. The dawning era of limited and expensive energy will be very difficult for everyone on earth but will be even more difficult if it is not anticipated. It is of utmost importance that the public and policymakers understand the global energy crisis and act in tandem to ensure that the species 'homo sapiens' does not become extinct. Biomass is an energy source used in
The rolling contact bearings as compared to sliding contact bearings have
Consider that modern machines mostly use short bearings due the following reasons: 1) l/d of the most modern bearings is in the range of 1.4 to 2 2) No end leakage of oil from the bearing 3) Shaft deflection and misalignment do not affect the operation 4) Can be applied to both hydro-dynamic and hydrostatic cases Which of the above are correct?