Monday, September 15, 2008

why do u dream...???


The Falling Asleep Process
During the day when we are a awake, our body and brain are working tirelessly to operate our body, and as they do so they slowly degrade at a cellular level. A person will get progressively tired from this bodily breakdown, because sleep gives us a chance to build and replace the cells and resolve our end of day homeostatic imbalances.
If you have not slept for a while, the decrease in the efficiency and effectiveness of the body begins to tell, and you will begin to feel sleepy as less energy is available to you. The longer we stay up the more likely we will fall asleep.
If certain conditions prevail, like a state of inactivity or relaxing in a warm dry place, there is a higher chance of us falling asleep due to the preferable conditions for us to do so.
Sleeping
When we fall asleep, our metabolic rate slows down, as does almost every other function across the board, we effectively go into hibernation mode. The amount of adrenaline in our body promoting awareness decreases and somatotrophin, controlling the repair of tissue is more abundant. This is effectively the healing process of sleep that revitalises us.
The synaptic nerve connections containing recollections about the last day are also strengthened, hence when you wake up the more you realised you did yesterday. This localised area of memory is what many of our dreams consist of, our past recollections of the day. You may have dreamt something twice, and on the second time it was only because you thought of that first dream the day before you dreamt the second. When looking at it like this, it confirms the reason why you have the same dream, your conscious thought about it accesses that part of the brain thus 'remembers' it at night.
Dreams Telling the Future?
Some people believe that dreams tell the future. But, when 6 billion people dream every night, there is bound to be a coincidence when there are trillions of dreams every year. Those people who have dreamed of winning the lottery are one of many.
I, personally don't believe they tell the future, though could be a sign of intelligence, the brain interpreting possibilities in the future from the knowledge of past events. This would be perfectly viable, as it would be a case of the brain 'adapting' to its future environment, and preparing you for the possible future.
REM
REM stands for rapid eye movement and is the points in time during sleep where dreams occur. They occur after periods of deep sleep.
As suggested, rapid eye movement occurs in REM, while the body is under a state of paralysis.
In effect, our brain takes us on a virtual reality of our thoughts while it steadily repairs itself for the next day. The most vivid and deepest dreams will occur in the periods between REM while drowsy, almost conscious dreams occur in the REM stages.
Our Environment Outside Sleep
Have you ever had a dream where someone next door is playing music, and the music is conveniently woven into your dream? This is your body trying to lessen the chances of you awakening while it is repairing itself.
However, sleep deprived people go into much deeper sleep, and may not detect such noises. The overriding point here is, that sleep is essential to the body, and that there are compensations made to our usual behaviour (like paralysis) that enables our body to do what is required for itself.
Sleep Troubles
The older we get, the less sleep we require. Teenagers buck the trends in needing the most sleep of us all, due to the growth spurt occurring at puberty that involves a larger turnover of materials and energy.
Newborn babies can sleep up to 60% of the day
Adults require around 7 hours minimum
With aging, the amount required is less due to the gradual degeneration of parts of the body that are not getting repaired.
Certain drugs are available to induce sleeping, but most are addictive and require controlled and responsible use. The next page looks at the works of famous past neurologists like Carl Gustav Jung and Sigmund Freud, who both actively pursued the way in which we dream as a career in neurology.

want to impress girls......???


Everyone can name someone who's nice, pretty, smart, funny, etc. Want to impress that certain girl? Here's what to do and what not to do.
Steps


Be well-groomed. Brush your teeth, floss, shower, wash your hair, and apply acne medicine (if you have a problem with your skin) daily. Don't wear your pants off your butt, it's not that attractive to the majority of girls. This is essential if you are even going to approach an attractive girl. Wear clean, attractive clothes (if in doubt, get an older sister or close female friend to help you in this department).
Have a good attitude. No girl likes to watch a guy put on a show, so be yourself. Don't try to impress everyone - girls like humble guys. At the same time, a sense of humor is always a plus.
Show respect. If you respect everyone and give them their space, they'll all respect you. With girls, it works even better. If they see you respecting everyone, and not getting pushed around while you're at it, they will be reassured that you will treat them right. Be kind to all.
Have good conversations. Don't talk about how you beat the big-bad-boss on level 23 gazillion of a video game...unless you know them well enough that you know they play that game, or are at least semi-interested (otherwise, it's just a big jumble to her). Try to aim for you both to be speaking 50% of the time, but make sure that you are saying something worthwhile; it's not attractive when only one person talks endlessly.
Show interest in her - let her talk. The #1 mistake when talking to a girl is focusing on yourself. Girls are way more comfortable when they talk about common interests. Ask about their interests, hobbies, favorite books, music, etc. but not in that stalker kind of way. If she asks you a question, answer it in a few, short sentences and then redirect the question back at her. This engages her in the conversation. When in doubt, compliment her.
Try flirting! If you both make eye contact, do not be the one to look away, but do not stare for too long. When you both make eye contact, just give a slight smile. She may look away and she might blush a little. Be careful though; you don't want to stare her down. A good move is to look away, and if she likes you she will shoot you glances. Watch for that.
Respect her friends and their ideas and opinions. Always speak highly of her and never talk trash about her. It will damage her reputation and yours and she'll possibly dump you. Of course, her friends are going to tell her that you trash talked her. Hopefully then it will work both ways - she will be tolerant of your friends. Be careful not to compliment her friends too much, however. Example: You may say "Your friends seem cool. We should hang out with them and my friends some time, I think they'd get along". You may not say "Sally is so hot. She has the nicest eyes".
Have your friends be nice to her It's a fantastic thing when your friends don't make a total fool of you. Warn them ahead of time and avoid topics pertaining to embarrassing moments of your past or awkward jokes that make very little sense.
Be polite to her parents. Be kind to everyone, especially them. Don't be too over-the-top charming with the parents, however, or they'll think that you have something to hide.
Don't criticize her. Unless she asks for constructive criticism.
Be romantic, but not over the top. If you've been dating for a while you may attempt a grand romantic gesture (note: "A while"=a month MINIMUM) otherwise, you'll look like a stalker.
Start talking to her casually. If you don't know her, make friendly conversation. Ask for the time, and/or compliment her watch.
Do not play "hard to get". Sure, you'll get their attention for a day or two then after a while, the girl will end up frustrated or think that you hate her for whatever reason, and she'll think you don't find interest in her anymore. Or if she likes a guy who's like that, her friends might not like you because you're acting like a jerk (this happens way too much).
Be careful with what you say. Remember, Hotty McHotterson is not your pal Lenny. Do not discuss bodily functions in her presence, or make jokes of a sexual nature unless she starts doing so.
Hum a few bars of a song she likes around her. She might think of you whenever she hears that song. And she'll probably be impressed by your good taste in music. Some girls have actually dumped guys or stopped liking guys when they insulted the music they like. So, it's OK not to like her music, but don't be insulting her favorite singer/band! Try to agree with her as much as possible but not so over the top that she knows your not being yourself. Make sure the song is not overtly feminine however. For instance, a Killers song is okay, an Ashley Tisdale song, not so much.
Start an inside joke with her! She will feel included and become closer to you. It also gives you an easy-to-come-up-with conversation starter. Try not to overuse it and kill the joke.
End later meetings with a hug, or plans to meet some other time, if you can.
Do not tell her that you "like her". Ask her out. If she rejects you, all is well. Example: You: "Betty, want to go to dinner on Saturday night?" Betty: "Sorry, I just think of you as a friend" You: "Oh, no offense. A bunch of us were talking about going, and I thought you might like to join us."
Try to get her attentions to your plus and away from minus , but be original !!!
Touch her ocassionally, like on the shoulder or hand.(but be sure to do it in a non-threatening way)!
Opposites attract. Be a courageous gentleman, not coy like a lady might be. Stand up for her,

Tips


If you hold a girl around her hips, it will seem like a romantic move for her. Girls LOVE romantic moves. She will feel important, and that someone actually likes her. If she says to stop, stop. Nothing is worse then then a girl seeing you as a harrasser. If she acts a little odd, stop. Don't take it personally because some girls just don't know how to act around guys. Do it another day if this happens.
Show sympathy and affection. If the girl you really enjoy being around is sad or hurt, give her a quick hug. Don't just say that you're sorry and you hope she feels better. Hold your left arm around her waist, right hand at the base of her neck or holding her head.
If you have braces, glasses and acne... don't be disheartened! Wear contacts, use some Proactiv/Accutane, and voila. Girls put a lot of effort into their appearance, perhaps you should do the same. But don't think just because you have braces, glasses, or acne, that the world is over, sometimes it works! Many people believe that braces are a fashion statement!
Have good posture!
Don't act tough or try to be a thug. This doesn't attract girls.
Don't follow her around everywhere. It automatically gives you a reputation as a stalker, and it will freak her out. Even following her just a little can create a stalker rep., depending on how you act. How you act can determine weather she will actually want you to be around her all the time or if even just seeing your face is too much contact. if you know she see's you as a stalker, lay off because trying to do damage control tends to just worsen your situation, instead try to get a friend of your or of hers to help your issue.
If she just doesn't get that you like her (which most likely won't happen because girls are pretty good at detecting this kind of stuff!) drop hints.
Don't play games. Waiting a few days to call her , showing up a little late to things or anything like that is only proving you are unreliable, a fake and a loser. Likewise, don't tolerate it if she does any of these things to you.
Use correct grammar when texting her or talking to her. If you don't then she will think that you aren't very intelligent and that will turn certain girls off.
While it's important to connect to her friends, you must avoid coming off as a player. If a girl's friends do not approve of you, this will influence her opinion of you.
Don't be weird around her.
Don't be a fake.

Warnings


If you have followed all the steps above and it didn't work, don't feel disheartened. Be proud that you made an effort and accept that it wasn't meant to be. If you decide to still be friends, don't be bitter if she moves on to a new guy.
Also, it says above that some girls like to talk about themselves- remember, some girls do. Some also would rather not have you obsessing about her hobbies, sports, etc. Be cool. Relate what she's saying to something about you, and then continue the conversation.
[Remember to talk about yourself and your own hobbies etc. That way you come off as a good conversationalist and as a person with a life.]
Every girl is different! Find out if she likes tattoos before you show her the skull and crossbones tattoo on your chest! (It's probably a bad idea to get a skull and crossbones tattoo on your chest (or elsewhere))
Never rush her or pressure her or show her a bad attitude.
Don't talk about her weight or ask her anything related to this subject. Even the girls with the most attractive bodies have insecurities. Even a comment intended as a joke could seriously hurt her feelings. Leave this subject alone.
At the same time, keep your own weight in check. Eat healthfully and work out. Don't go too crazy with the body building, but being toned never hurts. Watch out for skinny-fat (where you are skinny but flabby).
Girls love confident guys, but don't be cocky. A cocky guy turns girls off.
If you have problems with shyness, think of the most confident person you know and of what they would do in each situation. Don't be fake, just change your mindset.
Girls like that you care enough to buy them something. Don't go overboard and get flowers for her unless the time calls for it or she is very likely to think you did something wrong.
Some girls don't really know what to talk about with a guy so they might tend to talk about things you don't care about or go on and on about who said what. Don't be mean about it even though you're fighting boredom because it could of taken her a lot of courage to talk to you. Just show interest and change the subject to something more interesting, or politely exit the conversation.
Do not chew gum when talking to her. You should throw it away, if there are no trash bins, do not chew with your mouth open, pop, or blow bubbles.

how to impress guys..???


Not really sure how to catch his attention? Here's how to impress him and show him that you're confident and happy


Smile if you get near him or see him once he looks at you.
Twirl your hair or talk to your fellow classmate acting happy. 'Do not look sad or change your tone. A guy could notice that easily.
Make the first move. Most girls don't think they should, but it's normally worth it. A guy would love to know that a girl isn't so shy and is setting a comfortable environment around him.
Ask him a question. Guys love that a girl is actually the one who flirts with him first. Once you get to know him better, don't be afraid to start giving him hugs and such because it will help the guy know you like him.
Compliment him. You could say, "I like your shirt," or, "I love your hair," but make it kind of casual, guys like feeling confident.
Also act as if your flirting, but when you go up to him, just compliment him on something you admire him for. He will feel less pressured to go to you and talk then

TIPS>>>


Be yourself. Don't act like someone you're not. Guys really don't like that.
Don't be afraid to be different either. Most guys prefer girls who are not the exact same as every other girl on the planet. Don't feel like you have to fit all the latest trends or do what the popular kids do.
Try to look your best when doing this. Do not let other girls get in the way of you trying to impress your crush/ex-crush.
Scrunch hair, curl hair, straight and shiny, or do a messy do. It's a hot trend for guys.
Do not wear with tight shirts or short skirts all the time when you want to impress him. All he will be doing is checking you out. Guys don't remember what you wear and really don't care.
Guys always like a cute smile and a flirtatious scent.
Try to look as cute as possible without getting all of the other guys to look at you.
Make sure that you aren't impressing the wrong guy.
If you have tried to get the same guy once before and failed, try looking cute every day and ignore him. He will pick up that you really care for him.
Do not try too hard. This is a major turn off, and it makes it look like you're obsessed. Even if you are obsessed, you don't want to show it.
Don't act exactly like him, he's going to think your trying too hard, and boys, they don't play that, they want a unique individual just try to stay yourself just like you would with your guy friends, just a bit more flirtacious.
WARNING

Don't act too flirty with him, just enough for him to take the bait.
Don't flirt with his best friend/friends ever.
Don't physically hurt him if he flirted with you. This isn't grade school. Be nice, be gentle, make him smile, not cry.
IMPORTANT**Don't forget that us guys (mostly) fend for ourselves, and (most) girls wait for guys to ask. So some guys might be a little shy around you, but guarentee that he'll lose it in the first month or so, just give it time.
Don't feel weird when you smile. Us guys think it's one of the cutest things in the world when you smile.
If your trying to impress your ex then do something that will make him remember when yall were going out. That will let the guy know that you really like him and might get his attention
When you're walking together down the halls, stay close to his side. Don't make a big deal of it, act natural. This will show him you aren't afraid to be close to him.
Act nice to his friends. He will see that you are a nice person but dont flirt with his friends or he'll get the wrong message.

want to lose weight...???


Want a flat tummy? Read this article. We will explain everything that you need to know to accomplish your aim! This article explains all the concepts of weight loss and how you can “actually” and “practically” loose weight.If you have tried to loose weight in the past and did not get results, it is probably because you were doing something wrong. There is a LOT of weight loss advice out there! Most of this advice is just a scam! There are a lot of misconceptions about weight loss too. In this article, we will explain weight loss in a scientific and practical way. You will be able to decide what you need to do to accomplish your weight loss aims and you will be able to do it!Okay, lets begin….

Why do you gain weight?

Kilogram is a unit of weight. What do we mean by this? By this we mean that, wherever you go and tell someone that you want 5Kg of something, he will know much you are asking for. Kilogram is a standard that everyone accepts. Everyone knows that when you say “kilogram” there is pre-decided value you are asking for. That is what we mean by a unit. A unit is an accepted or decided value of something.So, when we say that a calorie is a unit of energy, we mean that a particular amount of energy is called a calorie. So, if you eat a sandwich and some amount to energy is obtained from the sandwich, we can say that the sandwich is worth 50 calories or the sandwich is worth 20 calories depending on how much energy is obtained from the sandwich.Why is all this important? All this is important because “counting the calories you consume” is big part of the loosing weight process. You see, as we said earlier, everyday you need a certain amount of energy i.e. everyday you need a certain amount of calories. Now, you generally get these calories from the food you eat. But, if you require 2,500 calories per day and you eat food worth 3000 calories, then you have 500 excess calories per day.
As we said, the body saves all this excess energy in the form of fat. This, is basically why you gain weight! You eat more than your body needs! So if you have to eat just the right amount, you need to know…

The body is a very very “efficient” machine. It is very sophisticated and evolved. One of the main things your body is made for is “survival”. You know, that you need energy to live and do the things that you do. This energy comes from food. The food you eat is converted into energy. When you “feel hungry”, that is the body telling you that you need to take in some food because the body needs some energy. As you probably know, energy is NOT ONLY required for actually doing things. You need energy to walk, talk, push, pull etc. But, besides that, the body still needs energy even if you are doing nothing! Even if you are just lying down on your bed, the body still needs energy. Why? The body needs this energy to keep the heart pumping, keep all the different organs functioning etc. All these internal processes take up some energy. So whether you do something or do nothing you still need a certain amount of energy each day to stay alive. Now, as we said earlier, the body is very sophisticated and made for survival! It prepares for a “rainy day” or a situation where you will have nothing to eat. The average adult can survive for a few weeks without any food before he/she has any serious medical problems. This is possible because the body saves any excess energy that is taken in!Here is the part we are interested in: The excess energy that you take in, is stored in the body in the form of “fat”!To understand all this properly, you need to understand the concept of “calories”..

What are calories? - Why are they so important?

Calories are NOT fat! Calories are energy! Or more correctly speaking, calories are a unit of energy. Just incase you are not sure what a “unit of energy means”, let us try to understand the concept of a “unit”.

How much energy does your body need?

Depending on your age, weight, the activities you do, etc. you will need a certain amount of calories. If you go for a run every morning, you will require more energy and more calories per day. If you are an athlete you will require more calories per day. If you sit, and work on a computer all day, you will require fewer calories per day. How many calories do you require, can be roughly calculated by using a calculator like this one. So, now what? Now that you know how many calories per day you need, then what? Now you got to figure out, how many calories per day you consume. How do you do this? As your day progresses, make a note of everything that you eat. Each and everything, no matter how small it is. Then, after that, use this calculator. Put in all the things that you ate into the calculator. For each thing you put, you will get a “Calorie” value. Note that value. (You will also get a “Fats” value. Forget about that!) After you have noted all the values, add them all up. This will be your total calorie intake for that day.

Origin Of GOD and Vacuum



If God created us, who created God? This is the question often raised by atheists. Most theists will answer this question by saying that God has no cause (discussion). Similarly, if you ask a physicist: what is the origin of the physical laws? He may answer that the physical laws have no cause.
We know our universe has something, but something cannot arise from nothing. We must assume certain things that are self existent (the aseity). In theology, God is the aseity while in science physical laws are the aseity. Since we are trying to understand the Kingdom of God from a scientific point of view, we shall accept physical laws as the aseity.
The "Physical God"
Most people will agree that "God" can be defined as the creator of the three-dimensional world that we live in. According to the string theory, our three dimensional world is a braneworld embedded in a higher dimensional space (possibly 10 dimensions). As shown in previous articles, our braneworld could be created by the highly intelligent life living in the bulk space (the space outside of any branes). The highly intelligent life in the bulk space is the "God" we are referring to.
By this definition, God should also be made up of matter. The elementary particles that constitute His matter are entirely different from us (see What is the Kingdom of God Made of?). However, they should still be governed by the physical laws that apply to all kinds of particles. These general physical laws include the conservation of energy, the second law of thermodynamics, the Heisenberg's Uncertainty Principle, and the Einstein's equation that relates energy to the mass of a particle: E = mc2.
We do not know the initial condition of the bulk universe. The most natural assumption is that it started with an empty space. That is, before any matter was created, the bulk universe contained only vacuum. As shown below, physical laws allow highly intelligent life (God) to evolve from the vacuum.
How could matter be created from vacuum?
According to Einstein's equation, the particles that constitute matter contain energy. On the other hand, the energy conservation law states that the total energy of a closed system must be a constant. It is impossible to create or reduce the total energy. Then, how could matter be created from vacuum? Would it violate the energy conservation law?
The key point that matter can be created from vacuum is that the gravitational potential energy is negative, which may cancel the positive mass energy of the matter. This possibility even surprised Albert Einstein, as told by George Gamow in his book My World Line. In the 1940s, a colleague of George Gamow had an idea that a star could be created out of nothing if its negative gravitational energy precisely cancels out its positive mass energy. One day, Gamow mentioned this idea to Einstein while they were walking in Princeton. Einstein immediately stopped in his tracks and fell into deep thought. Since they were crossing a street, several cars had to stop to avoid running them down.
In reality, a star is unlikely to be created out of nothing because its gravitational energy is too small to cancel out its huge mass energy. However, there is a mechanism that can facilitate the creation of small particles from vacuum: quantum fluctuation.
Quantum fluctuation
According to Heisenberg's Uncertainty Principle, we cannot determine energy and time precisely. Therefore, it is possible for a group of particles with non-zero total energy to appear naturally and then disappear within a short time. The more the total energy is created, the shorter the lifetime. This process is known as the quantum fluctuation. Because of quantum fluctuation, the vacuum cannot be absolutely nothing. It should still have some energy (the vacuum energy).
In the past several decades, quantum fluctuation has been widely used by cosmologists to explain the origin of the Big Bang that started our braneworld. However, the Big Bang involves the creation of a huge amount of energy that is unlikely to arise from quantum fluctuation. A more likely scenario is that the Big Bang was created by God in the bulk space and the Kingdom of God was created by quantum fluctuation.
Although the lifetime of the particles created by quantum fluctuation is short, they may decay into other types of particles or interact with each other to form stable particles during their lifetime. As time proceeded, some structures equivalent to our atoms could be formed. Eventually, a habitable environment and life could be developed. Since the bulk universe is eternal, there was plenty of time for an intelligent life to evolve from tiny particles.
Restriction in our braneworldNearly all elementary particles that constitute ordinary matter in our braneworld contain electric charges. These matter particles are restricted by the charge conservation law. Thus, the creation of a particle usually requires the creation of its antiparticle (with identical mass, but opposite charge). However, a particle can annihilate its antiparticle, making self-creation of matter particles by quantum fluctuation virtually impossible in our braneworld. In the labs, physicists can only observe the self-creation of the lightest particles, the electron-positron pair (positron is the antiparticle of the electron), which exists only for a very short time.
The elementary particles in the Kingdom of God are entirely different from ordinary particles in our braneworld. Most of them may not have electric charges. Without the charge-conservation restriction, the self-creation of particles may be quite common in the bulk space.

Sunday, September 14, 2008

History of Tattoo


The word Tattoo has been derived from the Polynesian word 'tatao', which means tapping or marking something. This term was first coined by Captain James Cook in the year 1769, when he met the Tahitians during his voyage, who had decorated their bodies with tattoos. At that time, tattooing was a very painful procedure. The technique of tattooing has now undergone a major modification. Read on to know more about the origin & history of tattoo.
Initially this body art involved piercing into the body, which was done by dropping a sharp-pointed comb into lampblack and then inserting it into the skin. Despite the trouble involved, many people got their bodies tattooed, especially arms. The tradition of tattooing, which was originally practiced in Tahiti and other Polynesian islands spread its influence in Europe too. In those days, it was mainly worn by the sailors, drunkards and criminals.The archeological excavations have revealed that this tradition of tattooing has been an integral part of many ancient cultures. In the year 1992, in the Alp region that lies between the border of Austria and Italy, a properly preserved body of a man was found. According to the estimations of the archeological department, it is expected that this man died near about 5000 years ago. He had 58 tattoos all over his body. Most of the ancient Egyptian mummies had tattoos. The Greeks and Romans of the bygone times used tattoo for identifying the slaves and criminals.

nanomaterials


Nanomaterials are materials with morphological features smaller than a one tenth of a micrometre in at least one dimension. Despite the fact that there is no consensus upon the minimum or maximum size of nanomaterials, some authors restricting their size from 1 to ~30 nm, a logical definition would situate the nanoscale between microscale (0.1 micrometre) and atomic/molecular scale (about 0.2 nanometers).

Fundamental concepts

A unique aspect of nanotechnology is the vastly increased ratio of surface area to volume present in many nanoscale materials which opens new quantum mechanical effects, for example the “quantum size effect” where the electronic properties of solids are altered with great reductions in particle size. This effect does not come into play by going from macro to micro dimensions. However, it becomes dominant when the nanometer size range is reached. Additionally, a number of physical properties change when compared to macroscopic systems. Novel mechanical properties of nanomaterials is the subject of nanomechanics research. Their catalytic activity reveals novel properties in the interaction with biomaterials.
Nanotechnology can be thought of as extensions of traditional disciplines towards the explicit consideration of these properties. Additionally, traditional disciplines can be re-interpreted as specific applications of nanotechnology. This dynamic reciprocation of ideas and concepts contributes to the modern understanding of the field. Broadly speaking, nanotechnology is the synthesis and application of ideas from science and engineering towards the understanding and production of novel materials and devices. These products generally make copious use of physical properties associated with small scales.
Materials reduced to the nanoscale can suddenly show very different properties compared to what they exhibit on a macroscale, enabling unique applications. For instance, opaque substances become transparent (copper); inert materials become catalysts (platinum); stable materials turn combustible (aluminum); solids turn into liquids at room temperature (gold); insulators become conductors (silicon). Materials such as gold, which is chemically inert at normal scales, can serve as a potent chemical catalyst at nanoscales. Much of the fascination with nanotechnology stems from these unique quantum and surface phenomena that matter exhibits at the nanoscale.
Nanosize powder particles (a few nanometres in diameter, also called nanoparticles) are potentially important in ceramics, powder metallurgy, the achievement of uniform nanoporosity and similar applications. The strong tendency of small particles to form clumps ("agglomerates") is a serious technological problem that impedes such applications. However, a few dispersants such as ammonium citrate (aqueous) and imidazoline or oleyl alcohol (nonaqueous) are promising additives for deagglomeration.

Size concerns

Another concern is that the volume of an object decreases as the third power of its linear dimensions, but the surface area only decreases as its second power. This somewhat subtle and unavoidable principle has huge ramifications. For example the power of a drill (or any other machine) is proportional to the volume, while the friction of the drill's bearings and gears is proportional to their surface area. For a normal-sized drill, the power of the device is enough to handily overcome any friction. However, scaling its length down by a factor of 1000, for example, decreases its power by 10003 (a factor of a billion) while reducing the friction by only 10002 (a factor of "only" a million). Proportionally it has 1000 times less power per unit friction than the original drill. If the original friction-to-power ratio was, say, 1%, that implies the smaller drill will have 10 times as much friction as power. The drill is useless.
This is why, while super-miniature electronic integrated circuits can be made to function, the same technology cannot be used to make functional mechanical devices in miniature: the friction overtakes the available power at such small scales. So while you may see microphotographs of delicately etched silicon gears, such devices are curiosities with limited real world applications, for example in moving mirrors and shutters. Surface tension increases in the same way, causing very small objects to tend to stick together. This could possibly make any kind of "micro factory" impractical: even if robotic arms and hands could be scaled down, anything they pick up will tend to be impossible to put down. The above being said, molecular evolution has resulted in working cilia, flagella, muscle fibers, and rotary motors in aqueous environments, all on the nanoscale. These machines, however, exploit the increase of the frictional forces found at the micro or nanoscale. Unlike an oar, paddle or propeller the mechanics of which are dominated by normal frictional forces (the frictional forces perpendicular to the surface) for propulsion, cilia, etc., develop motion resulting from the exaggerated drag or laminar forces (frictional forces parallel to the surface) present at micro and nano dimensions. To develop meaningful "machines" at the nanoscale, the relevant forces need to be considered. We are faced with the development and design of relevant machines rather than the simple reproductions of macroscopic ones.
All these scaling issues have to be kept in mind while evaluating any kind of nanotechnology

Materials used in nanotechnology

Materials referred to as "nanomaterials" generally fall into two categories: fullerenes, and inorganic nanoparticles. See also Nanomaterials in List of nanotechnology topics

Fullerenes

The fullerenes are a class of allotropes of carbon which conceptually are graphene sheets rolled into tubes or spheres. These include the carbon nanotubes which are of interest due to both their mechanical strength and their electrical properties.
For the past decade, the chemical and physical properties of fullerenes have been a hot topic in the field of research and development, and are likely to continue to be for a long time. In April 2003, fullerenes were under study for potential medicinal use: binding specific antibiotics to the structure to target resistant bacteria and even target certain cancer cells such as melanoma. The October 2005 issue of Chemistry and Biology contains an article describing the use of fullerenes as light-activated antimicrobial agents. In the field of nanotechnology, heat resistance and superconductivity are some of the more heavily studied properties.
A common method used to produce fullerenes is to send a large current between two nearby graphite electrodes in an inert atmosphere. The resulting carbon plasma arc between the electrodes cools into sooty residue from which many fullerenes can be isolated.
There are many calculations that have been done using ab-initio Quantum Methods applied to fullerenes. By DFT and TDDFT methods one can obtain IR, Raman and UV spectra. Results of such calculations can be compared with experimental results.

Nanoparticles

Nanoparticles or nanocrystals made of metals, semiconductors, or oxides are of interest for their mechanical, electrical, magnetic, optical, chemical and other properties. Nanoparticles have been used as quantum dots and as chemical catalysts.
Nanoparticles are of great scientific interest as they are effectively a bridge between bulk materials and atomic or molecular structures. A bulk material should have constant physical properties regardless of its size, but at the nano-scale this is often not the case. Size-dependent properties are observed such as quantum confinement in semiconductor particles, surface plasmon resonance in some metal particles and superparamagnetism in magnetic materials.
Nanoparticles exhibit a number of special properties relative to bulk material. For example, the bending of bulk copper (wire, ribbon, etc.) occurs with movement of copper atoms/clusters at about the 50 nm scale. Copper nanoparticles smaller than 50 nm are considered super hard materials that do not exhibit the same malleability and ductility as bulk copper. The change in properties is not always desirable. Ferroelectric materials smaller than 10 nm can switch their magnetisation direction using room temperature thermal energy, thus making them useless for memory storage. Suspensions of nanoparticles are possible because the interaction of the particle surface with the solvent is strong enough to overcome differences in density, which usually result in a material either sinking or floating in a liquid. Nanoparticles often have unexpected visible properties because they are small enough to confine their electrons and produce quantum effects. For example gold nanoparticles appear deep red to black in solution.
Nanoparticles have a very high surface area to volume ratio. This provides a tremendous driving force for diffusion, especially at elevated temperatures. Sintering can take place at lower temperatures, over shorter time scales than for larger particles. This theoretically does not affect the density of the final product, though flow difficulties and the tendency of nanoparticles to agglomerate complicates matters. The surface effects of nanoparticles also reduces the incipient melting temperature.

Safety of Manufactured Nanomaterials

Nanomaterials behave differently than other similarly-sized particles. It is therefore necessary to develop specialized approaches to testing and monitoring their effects on human health and on the environment. The OECD Chemicals Committee has established the Working Party on Manufactured Nanomaterials to address this issue and to study the practices of OECD member countries in regards to nanomaterial safety

While nanomaterials and nanotechnologies are expected to yield numerous health and health care advances, such as more targeted methods of delivering drugs, new cancer therapies, and methods of early detection of diseases, they also may have unwanted effects.

Increased rate of absorption is the main concern associated with manufactured nanoparticles.
When materials are made into nanoparticles, their surface area to volume ratio increases. The greater specific surface area (surface area per unit weight) may lead to increased rate of absorption through the skin, lungs, or digestive tract and may cause unwanted effects to the lungs as well as other organs. However, the particles must be absorbed in sufficient quantities in order to pose health risks