What is choke coil? Write its importance. 

Choke coil is a device used in ac to control; the current without significant loss of electrical energy in the form of heat.

It consists of large number of turns of thick insulated copper coil having small resistance to d.c. circuit. The coil has high inductance so it offers a large reactance X_L, in a.c. circuit. This control the alternating current so,Irms = Erms/XL

But the average power consumed in a pure inductance is zero. Thus choke coil is preferred to a resistance in an a.c. circuit to change the magnitude of current. 

D.C. Motor 

A motor is a machine for converting electrical energy into mechanical energy. It is based on the fact that a current carrying conductor experience a torque in a magnetic field. 

Construction 

A.C motor consists of an armature coil DCBA wound on a laminated iron core. It is placed in the magnetic field produced by current flowing through the field winding. The ends of the coil are connected to a split ring commulator which is in contact with brushes B1 and B2 to which a d.c. voltage is supplied.

working

Suppose a current from a battery flows round the armature coil in the direction DCBA. Assuming that the plane of coil is initially horizontal then, by fleming's left hand rule an upward force acts on DC and an equal downward force will act upon D.C. These force form a couple which rotates the coil in clockwise direction. but the couple become 0 when the coil is vertical, but owing to its monentum , the coil can pass the vertical position. the two half of split ring now make contact with the other two brushes as a result of which, the direction of current in the coil is reversed. hence the part of the coil moving upward in earlier condition will move down in this latter condition and viceversa and consequently the coil continues to move in same direction. each time the current pass the vertical position, the current in the coil reverses and thus the coil rotates continuously. the mechanical energy for driving the coil is obtained from the electrical energy supplied by battery. 

the motion of single coil is jerky so in order to obtain uniform motion, the single coil should be replaced by a number of evenly spaced coils, which are connected to a commulator having corresponding number of segments.

Hazards due to radio isotopes
Use of radioisotopes require careful consideration of their human toxicity. An individual handling radioisotope must not only think about its overdose but also should be conscious about its potential threats in the day to come because its effect may be prevalent over a decade. The hazard due to radioisotope can be summarized into following points. 
1. Genetic distortion: Write about mutation and take the example of Hirosima and Nagasaki
2. Cancer: Write about carcinoma formation
3. Blindness:
Properties of Ultraviolet rays and its application:
Properties
1. They don't carry any charged particle
2. It is electromagnetic wave so that it can never be deflected by electric or magnetic field. 
3. Due to high frequency compared to visible light, it has high energy. 
4. It shows florescence effect. 
5. It can effect the photographic plate
6. Its velocity is 3 x 10⁸m/s
Application 
1. Visible light is produced in CFL lamp due to striking of UV in the fluorescent powder coated inside CFL lamp. 
2. This light is used used in UV-Visible spectroscopy. 
3. In lab for analytical purpose
4. As disinfectant: to destroy microorganism 
5. Vitamin D is synthesized in human body in the presence of U.V light.

Check Page Rank of your Web site pages instantly:

This page rank checking tool is powered by Page Rank Checker service

Scientists Try To Thwart Flu Virus By Resetting Its Clock

Flu viruses can tell time. Sort of. And the viral clock-watching could provide a new way to fight the flu.
A study in Cell Reports describes how researchers tapped into the flu's internal clock as they search for ways to keep the virus from spreading.
Flu viruses hijack the machinery inside host cells to replicate. The theft is a complicated process that takes time. A virus enters the nucleus of the cell, copies itself thousands of times and then breaks out before the immune system attacks. Every minute counts.
"I like to equate it to a bank robber who knows that no matter what he does, he's going to set off some alarm," says Benjamin tenOever, a virologist at Mount Sinai School of Medicine who led the research. "In anticipation of that, he times what the police response is to get from the station to the bank."
While replicating, the virus directs the cell to produce a protein that the virus needs to exit. The protein level serves as a kind of hourglass for the flu. After about eight hours in the cell, the virus has enough to skedaddle and leaves.
To trick the flu, researchers fiddled with how fast the escape protein accumulates inside cells. Speed up the protein production, and the virus leaves the cell before it has made enough copies to infect someone else. Slow down the protein production, and the virus dawdles long enough to be rubbed out by the body's immune system.
TenOever hopes that this understanding of how viruses keep track of time will aid in creating more effective antiviral drugs and flu vaccines, though nothing like that is likely to materialize anytime soon. "If you could simply look for small molecules that interact with this protein, you would essentially cause the virus to live in the cells too long, which would give our immune systems enough time to catch it red-handed," he says.
And inoculating people with a defective virus that can't keep track of the time, tenOever says, "would allow even those who perhaps didn't have the same immune system strength of a 2- to 49-year-old to receive it because you're lowering the capacity of the virus to cause disease."http://www.npr.org/blogs/health/2013/01/17/169605208/scientists-thwart-flu-virus-by-resetting-its-clock

Whole Grains: Not always healthy

Whole grain foods may not always be healthy because the current norms for labeling them as such are inconsistent and possibly misleading, says a new Harvard study.

One of the most widely used industry criteria, the whole grain stamp, actually identified grain products that were higher in both sugars and calories than products without the stamp.

The benefits of switching from refined to whole grain foods are well established, including lower risk of cardiovascular disease, weight gain, and type two diabetes, the journal Public Health Nutrition reports. 

“Given the significant prevalence of refined grains, starches, and sugars in modern diets identifying a unified criterion to identify higher quality carbohydrates is a key priority in public health,” said Rebecca Mozaffarian, study author from the social and behavioral sciences department at Harvard School of Public Health.

Based on the evidences, the US Department of Agriculture’s (USDA) 2010 dietary guidelines recommend that Americans consume at least three servings of whole grain products daily and the new US national school lunch standards require that at least half of all meals be whole grain-rich. However, no single standard exists for defining any product as a “whole grain”.

From two major US grocers, researchers identified a total of 545 grain products in eight categories: breads, bagels, English muffins, cereals crackers, cereal bars, granola bars and chips.

They collected nutrition content, ingredients lists, and the presence or absence of the Whole Grain Stamp on product packages from all of these products, according to a Harvard statement.

They found that grains products with the whole grain stamp, one of the most widely used front of package symbols, were higher in fibre and lower in trans fats, but also contained significantly more sugar and calorie compared to products without stamp.

The three USDA recommended criteria also had mixed performance for identifying healthier grain products. Overall, the American Heart Association’s standard (a ratio of total carbohydrate to fibre) proved to be the best indicator of overall healthfulness. 

Source Himalayan Times

Hey guys i have got some tfp  II question. I will provide you more in coming days.

Don't know the title

I don't know whether I am lost or I am found from this monolithic world. How could i not be lost I am just a microcosm of this monolithic world. How am i lost? I am here, with me, me myself.

This is not only me who have this sorts of feelings. We laugh, cry, sing dance, born and die. What worth all these things keep if we don't exist and what should us pursuit if we don't exist? In fact each and every living creature has their own monolithic world of them self. The most precious thing for every one is their life.

One question always hits my mind." How could one greatest thing can accommodate on another greatest thing?"

This meretricious world only has two basic principle i.e.  relativity and hierarchy. You guys will feel me meandering because you are accelerating. We actually believe in the thing that we see. We will never try to invade the reality. We run on the system of hierarchy the powerful one always dominates the weaker one. Even billions of stars are dominated by a single sun. We people are bounded by the narrow intangible wall of love and hatred. We don't like to speak with someone because we hate them. We like to indulge our self on speaking with our beloved one because we love them. We people are somehow actuated by some sort of mercenary motives. Oh! See some guys are kidding the venerable man.

So, what?

 What will i get doing something for him?

Damn this hovel world where people are just living for leaving.

What worth thinking oneself world would be if other cannot stay in that world?

It's the greatest heart that exists inside somebody letting many more to live in. Finally my entire dilemma is solved. Nothing is wretched in our world just our thought is to be expurgated.

From: Krishna Kharel 

Astro Group Nepal

This is a photo of moon taken by Astro Group Nepal. You can get more photos in our facebook link.
search for National Association of Nanotechnology and Ultra-science.

Diet drinks may increase risk of developing depression

A study to be presented at the American Academy of Neurology’s 65th Annual Meeting in San Diego, Calif., March 16–23, shows that drinking sweetened beverages, especially diet drinks, may be associated with an increased risk of depression in adults. However, drinking coffee may be tied to a slightly lower risk.

January 9, 2013

A study to be presented at the American Academy of Neurology’s 65th Annual Meeting in San Diego, Calif., March 16–23, shows that drinking sweetened beverages, especially diet drinks, may be associated with an increased risk of depression in adults. However, drinking coffee may be tied to a slightly lower risk.
The study involved 263,925 people between the ages of 50 and 71 at enrollment. From 1995 to 1996, consumption of drinks such as soda, tea, fruit punch, and coffee was evaluated. About 10 years later, researchers asked the participants whether they had been diagnosed with depression since the year 2000. A total of 11,311 depression diagnoses were made.
People who drank more than four cans or cups per day of soda were 30% more likely to develop depression than those who drank no soda. Those who drank four cans of fruit punch per day were about 38% more likely to develop depression than those who did not drink sweetened drinks. People who drank four cups of coffee per day were about 10% less likely to develop depression than those who drank no coffee. The risk appeared to be greater for people who drank diet than regular soda, diet than regular fruit punches, and for diet than regular iced tea.
“Our research suggests that cutting out or down on sweetened diet drinks or replacing them with unsweetened coffee may naturally help lower your depression risk,” said study author Honglei Chen, National Institutes of Health. “More research is needed to confirm these findings, and people with depression should continue to take depression medications prescribed by their doctors.”
Food Technology 

Importance of omega-3-fatty acid

The fatty acid required for the human body can be broadly classified into two groups, non-essential fatty acid and essential fatty acid. Essential fatty acids are the fatty acid that is essential to our body as our body cannot synthesize it while non-essential fatty acid can be synthesized by our body.
Omega-3-fatty acid is one of the essential fatty acid. It's poly unsaturated fatty acid (PUFA). It is named so as there are one or more than one double bond in the structure of this fatty acid. The potential source of omega-3-fatty acid are fishes like salmon, tuna, and halibut other sea food includes algae and krill and also in almond and other nuts oil. It is essential as it plays a crucial role in the functioning of brain and normal growth and development additionally they reduces the chances of cardiovascular diseases. The American Heart Association recommends eating fish (particularly fatty fish such as mackerel, lake trout, herring, sardines, albacore tuna, and salmon) at least 2 times a week.

It is very essential for the people suffering from the diseases like high blood pressure, high blood sugar, osteoporosis, high cholesterol and many more.

A traditional food of Nepal Juju dhau

Nepal is a multicultural, multilingual country. there is not only diversity in the languages, ethnicity, culture but also in the food they eat. Dahi (yoghurt) is consumed through out Nepal though the production process is different. generally the production process of yoghurt can be classified in three categories:
Home made: It is the most simplest method of the manufacture of yoghurt. the pure culture is not used. the milk is boiled and the innoculum (Jodan) form the previous day yoghurt is added when the milk can be touched by our finger around 35-40 degree celcius. Syneresis (leaching of water), uncontrolled acidity, mixed flora in the innoculum are the major problem of this type of yoghurt.
Industrial scale yoghurt: this type of yoghurt is prepared in the industry. they make the use of pure culture (DVS: dry vat set). the culture consits of Lactobacillus thermophilus and Streptococcus lactis. The major problem of the home made traditional style of yoghurt manufacture is solved here. the industries uses its standard for the manufacture of yoghurt. DDC (Dairy Development Commission) has got the leading market in all dairy products.
Ju-Ju dhau: Ju-Ju dhau traditionally means the king of yoghurt. It is generally prepared in the community where Newari people are dominant. In this method of yoghurt manufacturing, the milk is let to form a coagulum in earthen pot. the milk is added in batch manner in the earthen pot kept over the husk to maintain the temperature. the milk is boiled to certain level of consistency. when the milk is poured in the earthen pot in batch process, finally the innoculum is added (2-3 spoon of the previous day yoghurt). then the coagulum is allowed to form.
there is still a lot of process that is to be modified in the manufacturing process of yoghurt of nepal so that the the yoghurt king Ju-Ju dhau will rule the entire world. 

Oxygen Radical Absorbance Capacity (ORAC), Anthocyanin, and Ellagic Acid Values

Recent testing has confirmed that Oregon black raspberries have astonishingly high antioxidant levels. Antioxidant levels, shown in terms of their oxygen radical absorption capacity (ORAC), are a measure of a substance's ability to absorb oxygen free radicals. Oxygen free radicals can damage DNA, cause cellular change, oxidize LDL cholesterol, and cause premature mental aging. Consuming foods high in antioxidants helps prevent cancer, heart disease, stroke, and possibly Alzheimer's Disease. When compared to other foods, black raspberries have extremely high ORAC values. They are also among the highest foods in anthocyanins. Anthocyanins give foods like black raspberries their deep, dark color and have been shown to have anti-inflammatory and vasoprotective properties. Research has linked anthocyanins with improved vision, cardiovascular health, memory retention in old age and reduced risk of hypertension. 

source: http://berryhealth.fst.oregonstate.edu/health_healing/fact_sheets/black_raspberry_facts.htm