Write short notes, not exceeding 150 words each, on of the following: (1) Homogenization of milk, (2) Extraction of oil from rice bran, (3) Strain gauge torque sensor, (4) Vapor compression refrigeration system, (5) Computer memory?

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1. Homogenization of milk:

Homogenization is a more recently invented process and it has been called “the worst thing that dairymen did to milk.” When milk is homogenized, it is pushed through a fine filter at pressures of 4,000 pounds per square inch. In this process, the fat globules are made smaller by a factor of ten times or more. These fat molecules then become evenly dispersed throughout the milk. All homogenized milk is produced by mechanical means. Milk is forced through a small passage at high velocity. Homogenization is an entirely separate process that occurs after pasteurization in most cases. The purpose of homogenization is to break down fat molecules in milk so that they resist separation. Without homogenization, fat molecules in milk will rise to the top and form a layer of cream. Homogenizing milk prevents this separation from occurring by breaking the molecules down to such a small size that they remain suspended evenly throughout the milk instead of rising to the top. Homogenization is a mechanical process and doesn’t involved any additives. It’s advantageous for large-scale dairy farms to homogenize milk because the process allows them to mix milk from different herds without issue. By preventing cream from rising to the top, homogenization also leads to a longer shelf life of milk that will be most attractive to consumers who favor milk without the cream layer. This allows large farms to ship greater distances and do business with more retailers. Finally, homogenization makes it easier for dairies to filtrate out the fat and create two percent, one percent and skim milk. Homogenization of cold milk, in which the fat is essentially solidified, is virtually ineffective. Processing at temperatures conducive to the partial solidification of milk fat (i.e. below 40 °C) results in incomplete dispersion of the fat phase. Products of high fat content are more difficult to homogenize and also more likely to show evidence of fat clumping, because the concentration of serum proteins is low in relation to the fat content. Usually, cream with higher fat content than 20 % cannot be homogenized at high pressure, because clusters are formed as a result of lack of membrane material (casein). Increasing the homogenization temperature decreases the viscosity of milk and improves the transport of membrane material to the fat globules. Homogenization temperatures normally applied are 55 – 80 °C, and homogenization pressure is between 10 and 25 MPa (100 – 250 bar), depending on the product. Milk is a hormonal delivery system. When homogenized, milk becomes very powerful and efficient at bypassing normal digestive processes and delivering steroid and protein hormones to the human body (both your hormones and the cow’s natural hormones and the ones they may have been injected with to produce more milk). Homogenization makes fat molecules in milk smaller and they become “capsules” for substances that are able to bypass digestion. Proteins that would normally be digested in the stomach are not broken down and instead they are absorbed into the bloodstream. The homogenization process breaks up an enzyme in milk which in its smaller state can then enter the bloodstream and react against arterial walls. This causes the body to protect the area with a layer of cholesterol. If this only happened once in a while it wouldn’t be of big concern, but if it happens regularly there are long term risks. Proteins were created to be easily broken down by digestive processes. Homogenization disrupts this and insures their survival so that they enter the bloodstream. Many times the body reacts to foreign proteins by producing histamines, and then mucus. Sometimes homogenized milk proteins resemble a human protein and can become triggers for autoimmune diseases such as diabetes or multiple sclerosis. Two Connecticut cardiologists have demonstrated that homogenized milk proteins did in fact survive digestion. It was discovered that Bovine Xanthene Oxidase (BXO) survived long enough to affect every one of three hundred heart attack victims over a five-year time period. Even young children in the U.S. are showing signs of hardening of the arteries.

2. Extraction of oil from rice bran:

Rice bran oil is the oil extracted from the hard outer brown layer of rice after chaff (rice husk). It is notable for its high smoke point of 232 °C (450 °F) and its mild flavor, making it suitable for high-temperature cooking methods such as stir frying and deep frying. It is popular as a cooking oil in several Asian countries, including Bangladesh, Japan, India and China. By weight, rice bran has 17% oil content. After the refining process, the refined rice bran oil weighs only 12% of the rice bran raw material. The extracting process starts with raw material preparation. Rice bran is first screened. It is then heated by steam at temperature higher than 100 degrees Celsius to stop Lipase hydrolysis in rice bran prior to extraction.

RBEP

3. Strain gauge torque sensor

A torque sensor or torque transducer or torque meter is a device for measuring and recording the torque on a rotating system, such as an engine, crankshaft, gearbox, transmission, rotor, a bicycle crank or cap torque tester. Static torque is relatively easy to measure. Dynamic torque, on the other hand, is not easy to measure, since it generally requires transfer of some effect (electric or magnetic) from the shaft being measured to a static system. One way to achieve this is to condition the shaft or a member attached to the shaft with a series of permanent magnetic domains. The magnetic characteristics of these domains will vary according to the applied torque, and thus can be measured using non-contact sensors. Such magnetoelastic torque sensors are generally used for in-vehicle applications on racecars, automobiles, aircraft, and hovercraft. Commonly, torque sensors or torque transducers use strain gauges applied to a rotating shaft or axle. With this method, a means to power the strain gauge bridge is necessary, as well as a means to receive the signal from the rotating shaft. This can be accomplished using slip rings, wireless telemetry, or rotary transformers. Newer types of torque transducers add conditioning electronics and an A/D converter to the rotating shaft. Stator electronics then read the digital signals and convert those signals to a high-level analog output signal, such as +/-10VDC. A more recent development is the use of SAW devices attached to the shaft and remotely interrogated. The strain on these tiny devices as the shaft flexes can be read remotely and output without the need for attached electronics on the shaft. The probable first use in volume will be in the automotive field as, of May 2009, Schott announced it has a SAW sensor package viable for in vehicle u ses.Another way to measure torque is by way of twist angle measurement or phase shift measurement, whereby the angle of twist resulting from applied torque is measured by using two angular position sensors and measuring the phase angle between them. This technique is used in the Allison T56 turboprop engine. Finally, (as described within the abstract for US Patent 5257535), if the mechanical system involves a right angle gearbox, then the axial reaction force experienced by the inputting shaft/pinion can be related to the torque experienced by the output shaft(s). The axial input stress must first be calibrated against the output torque. The input stress can be easily measured via strain gauge measurement of the input pinion bearing housing. The output torque is easily measured using a static torque meter.

4. Vapor-compression refrigeration

Vapor-compression refrigeration or vapor-compression refrigeration system (VCRS), in which the refrigerant undergoes phase changes, is one of the many refrigeration cycles and is the most widely used method for air-conditioning of buildings and automobiles. It is also used in domestic and commercial refrigerators, large-scale warehouses for chilled or frozen storage of foods and meats, refrigerated trucks and railroad cars, and a host of other commercial and industrial services. Oil refineries, petrochemical and chemical processing plants, and natural gas processing plants are among the many types of industrial plants that often utilize large vapor-compression refrigeration systems. Refrigeration may be defined as lowering the temperature of an enclosed space by removing heat from that space and transferring it elsewhere. A device that performs this function may also be called an air conditioner, refrigerator, air source heat pump, geothermal heat pump or chiller (heat pump).

Part 1: Compression

In this stage, the refrigerant enters the compressor as a gas under low pressure and having a low temperature. Then, the refrigerant is compressed adiabatically, so the fluid leaves the compressor under high pressure and with a high temperature.

Part 2: Condensation The high pressure, high temperature gas releases heat energy and condenses inside the “condenser” portion of the system.  The condenser is in contact with the hot reservoir of the refrigeration system.  (The gas releases heat into the hot reservoir because of the external work added to the gas.)  The refrigerant leaves as a high pressure liquid.

Part 3: Throttling The liquid refrigerant is pushed through a throttling valve, which causes it to expand.  As a result, the refrigerant now has low pressure and lower temperature, while still in the liquid phase.  (The throttling valve can be either a thin slit or some sort of plug with holes in it. When the refrigerant is forced through the throttle, its pressure is reduced, causing the liquid to expand.)

Part 4: Evaporation The low pressure, low temperature refrigerant enters the evaporator, which is in contact with the cold reservoir. Because a low pressure is maintained, the refrigerant is able to boil at a low temperature.  So, the liquid absorbs heat from the cold reservoir and evaporates.  The refrigerant leaves the evaporator as a low temperature, low pressure gas and is taken into the compressor again, back at the beginning of the cycle.

5. Computer memory

Memory is major part of computers that categories into several types. Memory is best storage part to the computer users to save information, programs and etc, The computer memory offer several kinds of storage media some of them can store data temporarily and some them can store permanently. Memory consists of instructions and the data saved into computer through Central Processing Unit (CPU).

Computer Memory diagram

Types of Computer Memorys:

Memory is the best essential element of a computer because computer can’t perform simple tasks. The performance of computer mainly based on memory and CPU. Memory is internal storage media of computer that has several names such as majorly categorized into two types, Main memory and Secondary memory.

1. Primary Memory / Volatile Memory.

2. Secondary Memory / Non Volatile Memory.

1. Primary Memory / Volatile Memory:

Primary Memory also called as volatile memory because the memory can’t store the data permanently. Primary memory select any part of memory when user want to save the data in memory but that may not be store permanently on that location. It also has another name i.e. RAM.

Random Access Memory (RAM):

The primary storage is referred to as random access memory (RAM) due to the random selection of memory locations. It performs both read and write operations on memory. If power failures happened in systems during memory access then you will lose your data permanently. So, RAM is volatile memory. RAM categorized into following types.

  • DRAM
  • SRAM
  • DRDRAM

2. Secondary Memory / Non Volatile Memory:

Secondary memory is external and permanent memory that is useful to store the external storage media such as floppy disk, magnetic disks, magnetic tapes and etc cache devices. Secondary memory deals with following types of components.

Read Only Memory (ROM) :

ROM is permanent memory location that offer huge types of standards to save data. But it work with read only operation. No data lose happen whenever power failure occur during the ROM memory work in computers. ROM memory has several models such names are following.

1. PROM: Programmable Read Only Memory (PROM) maintains large storage media but can’t offer the erase features in ROM. This type of RO maintains PROM chips to write data once and read many. The programs or instructions designed in PROM can’t be erased by other programs.

2. EPROM : Erasable Programmable Read Only Memory designed for recover the problems of PROM and ROM. Users can delete the data of EPROM thorough pass on ultraviolet light and it erases chip is reprogrammed.

3. EEPROM: Electrically Erasable Programmable Read Only Memory similar to the EPROM but it uses electrical beam for erase the data of ROM.

Cache Memory:

Mina memory less than the access time of CPU so, the performance will decrease through less access time. Speed mismatch will decrease through maintain cache memory. Main memory can store huge amount of data but the cache memory normally kept small and low expensive cost. All types of external media like Magnetic disks, Magnetic drives and etc store in cache memory to provide quick access tools to the users.

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