With the innovation of the internet buying a desktop alarm clock has never been easier. Until recently there was only one way to get a "desktop alarm clock" you had to go to a store and buy one. Not only you would have to select from a very limited number of desktop alarm clocks, but hopefully you will find one that would suit your tastes.Well, the problem with this approach to buying yourself an alarm clock for you desktop is that you are not likely to find sufficient styles of timepieces at any one store except if you go in knowing exactly what it is that you want. For instance, you may have no problem to find a digital desktop alarm clock at one store, but there might be no good looking analog kind with the classical look that some people may prefer. Or, just maybe you might find yourself in the position of shopping at a more expensive boutique and only discover flashy desktop alarm clocks with silly fake pillars at the sides of them, whilst all you want is something to display the time and maybe wake you up in the morning with a horribly annoying ring that is impossible to ignore.No matter what you want in a desktop alarm clock, it should be pretty easy to find one at the supermarket or even your local drug store. As a matter a fact, desktop alarm clocks are undoubtedly the easiest piece of electric gear, one can find anywhere so you shouldnt have a problem.For those who are looking for a desktop alarm clock, I recommend getting one with a clock radio, as the sounds coming out from the other one are really annoying, and for sure you can start off in a bad mood! Of course, you should also think about what you want the desktop alarm clock for. Well if you would like one to travel, perhaps you will find one for lesser than 15 dollars, wherein these small [*_*]s can be powered for quite some time on nothing more than a battery. On the other hand if you want something that will look nice in your room, however, the considerations are more comfortable.Frankly speaking, I hardly ever use my [*_*] now that I have an alarm clock on my computer desktop. To wake me up in the morning, it can play any of my mp3s in stead of having to put up with whatever is on the radio, or even worse that awful beeping that most [*_*]s have. In my opinion I believe it will soon leave the traditional [*_*] obsolete.
* What is an electron microscope?Invented by a German physicist named Ernst Ruska, electron microscopes are mostly used in archaeology, medicine, and geology to look at surfaces or layers of objecs. Rather than using light, electron microscopes use electrons to produce images. They have high resolution and can magnify in small detail.* What is a compound microscope?Used mostly in biology, compound microscopes have two or more double convex lenses. They produce a 2-D slice image of an object, yet can attain a high enough magnification to see a hair strand. Unfortunately, they do not have excellent resolution, so the image may be blurred. On the other hand, stereoscopic microscopes, as the name implies, provide a 3-D picture of bisected items, like muscle tissue or an organ.Compound microscopes are the simplest type of microscope and are found in many classrooms. Compound microscopes are operated entirely by hand and use ordinary ambient light from the sun or light bulb. The specimen is mounted between two glass slides, and the microscope system uses a simple series of magnifying lenses and mirrors to bring the image to the eyepiece, much like a telescope.* What is a stereo microscope?While a compound microscope provides a 3-D picture, a stereo microscope provides a 3-D picture of bisected items such as muscle tissue or organs. A stereo microscope is a lower-powered microscope with low magnification. Although you cannot make out separate cells, it does allow for closer viewing of the non-microscopic world.This microscope makes tiny objects gigantic and is sometimes called a dissecting microscope. Inexpensive models of stereo microscopes are available for schools and students. The stereo microscope has a zoom as well as improved optics and lighting and can be used for professional purposes.* What is a confocal microscope?A confocal microscope is a step down from those above. It uses a laser beam to illuminate a specimen. Then, the image is digitally enhanced and viewed on a computer monitor. The specimen is often dyed a bright color for a more contrasting image. Unlike compound microscopes, confocal microscopes are controlled automatically with motorized mirrors that help with auto-focus.* What is a digital microscope?Made up of a digital camera unit and a controller, a digital microscope is fairly new to microscopy. It utilizes USB technology to produce live images viewable on a computer monitor. A high pixel color CCD and light are built into the camera unit. It makes use of inverted lens design and has a rotatable lamp. The controller has various functions such as display, record, measurement, etc. The digital microscope allows for quick observation, analysis and data processing without much preparation.
Lithium Ion batteries were invented as long ago as 1912 by Gilbert N. Lewis, but it was a long time before they were developed enough to be launched on a mass market level. This happened in the early 1990s with Sony pioneering their commercial use.Lithium Ion batteries have many advantages.They can be constructed in a wide variety of shapes and sizes, resulting in them being tailored to the available space in the device in which they are to be used.The batteries are also much lighter than other equivalents, due to the nature of the material and the high open circuit voltage compared to other batteries. This low weight makes it ideal in hand held and mobile devices for obvious reasons, and popular in these days of high tech gadgets.Another major advantage is that they do not suffer from memory effect. This is the condition, whereby other rechargeable batteries, if not fully discharged before recharging, lose their maximum energy capacity over time and thus hold less charge.They also do not have such a drastic self discharge rate as other batteries just 5% per month, compared with up to 30% per month in other battery types.However, Lithium Ion batteries are not perfect, and there are drawbacks.One of these is that their life span depends upon their age and not the time from which they were charged, or the number of times they have been charged. They begin to lose capacity gradually from the date of manufacture irrespective of the amount of charging cycles they have. Therefore the manufacturing date is useful to know,e specially if there is a big time lapse from manufacture to being used e..g due to storage.Some Lithium Ion batteries (such as laptop batteries) can lose around 20% of their capacity per year, when stored at normal temperatures. However, when exposed to prolonged higher temperatures, this figure can increase to as much as 35% per year. Another key factor is the charge level when stored partially charged, these figures can be dramatically reduced.This makes Lithium Ion batteries unsuitable for certain applications such as back up batteries.The battery must never be discharged below a certain threshold, otherwise the battery will be damaged irreversibly. Therefore, the devices that use them have a built in system to shut them down when the charge level meets that minimum threshold. For this reason, Lithium Ion batteries are designed and manufactured specifically for the device they are to power and are not available as generic batteries.Having said that, there are some versions available that have a built in circuit to monitor the minimum charge level and shut the battery down when it reaches that level. These are known as smart batteries.How to prolong the life of your Lithium Ion battery- Charge the battery early and often , unlike other rechargeable batteries.- If you do not intend to use the battery for a long time, charge it to a level of approximately 40% of capacity.- The battery should be kept cool. They will age faster at higher temperatures, so keep as cool as possible when not in use. They can be safely stored in a refrigerator for optimum prevention of aging. (note: they should not be frozen)- If the device you are using is often run from a mains power supply (e..g laptop) and it is possible, remove the battery when using mains power. This prevent the battery from being subjected to high prolonged temperatures which can shorten its life.- Any steps to reduce the heat that the battery is subjected to will benefit its lifespan.- When purchasing replacements, try to purchase a battery that has the shortest possible time from manufacture to retail. (though it may be difficult to find out this information).In short Lithium Ion batteries are a very versatile battery, ideal in lightweight applications and not subject to memory effect. However, they do degrade at higher temperatures which means they are not a universal battery solution.
Little Red Riding Hood let the Big Bad Wolf in because she didnt know any better. Thanks to the latest video surveillance system, you can be sure whoever it is who is knocking and gently rapping at the door or huffing and puffing and puffing to blow your house down.Living alone in New York or anywhere else?Living alone in big cities or anywhere else in the globe may have its rewards. But security wise you have to arm yourself with the latest "video surveillance system" . It would be a big mistake to assume that surveillance cameras are only tailor-fitted for cloak and dagger settings. In this day and age, there is no telling who is at the door. It is better to be safe than sorry. One of the MOST handy video surveillance system that you can install yourself would not only save you money, but also your life and property.Meanwhile, back at home, your mother is probably worrying about your safety. So, next time she calls, assure her that you have already installed one of those video surveillance systems she keeps on harping about. Knowing that youve made the right move will make her breathe easier and your phone will stop ringing off the hook every night she checks on you. Investing in the best video surveillance system available for the home is the next best thing to having your own PC and iPhone. So check out what would be the best system for your place.The Right PickYou can get a wireless spy camera powered by a 9-volt battery. The battery has a receiver with a built-in USB. The neat package includes accessories, such as remote control and USB adapter. With this set, you wont need a separate USB video adapter. This will save you extra minutes to connect.Whats with this? This spy camera can be hidden anywhere you think is best. When the doorbell rings or when somebody knocks at your door, check the image in your PC. Even at a distance of 300 feet, the image can be recorded. Go for the wireless spy camera for your little domain. Choose a camera with infrared features too. Even in the dark, it can pick up clear images. This should complete your indoor and outdoor video surveillance system in your little domain. Surprise your mom when she drops by unannounced. Shell get a pleasant shock to know you are armed with a new toy.Maximum security from a dime-sized unitOnce you have your video surveillance system camera, connect the receiver with the USB adapter. Activate your computer and place the battery inside the wireless mini spy cam. You are set to see a colored image of anybody standing behind the door and hear the monoaural audio recorder. Yes, the wireless mini surveillance camera has recording software too.For such tiny things, you get maximum security in your apartment. Tell your mom and dad the good news. Theyll be sleeping easy this time around.
Wireless: To Be, Or Not To Be? That Is The Question Facing Schools Across The Country.There has been a lot of hype in the media about concerns wireless Internet connections (Wi-Fi) are harming children. But is there a basis to these concerns, or are these fears unwarranted?Probably the most concerning information to come out of these stories is that these wireless connections emit radiation with a similar frequency to microwaves and mobile phones. And that fact has got people worried that it might cause cancer, brain damage and heart disease, not to mention headaches, fatigue, nausea, dizziness and memory problems in the short term.A BBC Panorama investigation caused panic when they claimed that the radio frequency radiation levels of some classes that have Wi-Fi connections are up to three times more intense than the levels found in the main beam of intensity of mobile phone masts. However, The Guardian then quoted various scientists who refuted this claim, and essentially discredited the investigation.BBC News reported that while the heating effects of high exposure to electromagnetic radiation could be damaging, mobile phones and microwave ovens have a much higher power level than wireless connections. The report then pointed out that there is no evidence that suggests electromagnetic radiation at radio frequencies has any impact on health when the energy levels are at such low levels. In other words, there is no proof that Wi-Fi connections are bad for our health.In fact, The Times stated that a wireless-connected classroom in Norwich was tested, and the levels of radiation were found to be 600 times lower than the levels considered dangerous by the Government. The classroom was tested using the International Commissions NonIonizing Radiation Protection processes, which determines how strong radiation is based on how much heat is produced. Do the negative arguments stand-up?Despite the articles above, Sir William Stewart, the chairman of the Health Protection Agency who pointed out in 2000 that mobiles phones could be detrimental to peoples health, has been quoted in a number of newspapers warning of the potential dangers of Wi-Fi technology. He has issued a plea that students who come in regular contact with Wi-Fi technology should be monitored for any ill effects.Labour MP Ian Gibson, who was interviewed by Sir William Stewart for an upcoming programme, backed the statements made by Sir William Stewart, and called for an official inquiry into Wi-Fi connections. Gibson is MP for Norwich, a city that has recently been set up as a wireless city.These sentiments have been echoed by Mike Bell, chairman of the Electromagnetic Radiation Research Trust; Alasdair Philips, director of Powerwatch, an information service; and the Professional Association of Teachers, whom are currently pressuring Education Secretary Alan Johnson to call for one such inquiry.Dr Olle Johansson of Karolinska Institute in Sweden has been studying radiation similar to that being given off by wireless connections and found there are biological implications. However, when he was asked if it was right to limit Wi-Fi usage based on thermal effect, he refuted the idea.The Government believe the technology is perfectly safe, taking the advice from the World Health Organisation, and have not yet set up any official inquiry. Are our children safe?One of the greatest concerns is that of our children. Children are more vulnerable to radiation because their skulls are thinner and their nervous systems are still developing and because they will be exposed to more of this radiation during their lives.Although there is no evidence yet supporting the notion that wireless connections emit harmful radiation, the thought that children may be exposed to dangerous radiation, especially considering how many schools use the technology, has some parents up in arms.The Independent newspaper reported that according to some estimates, more than half Englands primary schools, and about four-fifths of their secondary schools, have Wi-Fi technology installed.In several European countries, provincial governments have banned or limited the use of wireless technology in their schools. And back home in Britain, Stowe school has removed part of their Wi-Fi technology after a teacher began having headaches and nausea as soon as it was installed.However there is a chance this teacher was just "electrosensitive", a condition that affects three out of one hundred people according to the World Health Organisation.In addition to this theory, James Rubin from the Institute of Psychiatry has stated that people can develop headaches if they believe such technology gives people headaches, even if the signal is not present. What are the advantages and disadvantages of Wi-Fi Internet Connections? Advantages of Wi-FiThe main advantage of Wi-Fi is users can connect to the Internet without being plugged in. As long as the computers are within range of a host network, users can log on to this network from anywhere.What this means is that students can be outside, or in areas where cables cannot run, and still be able to use the Internet.In addition, in some circumstances Wi-Fi can be cheaper to set-up and expand than a cabled network, especially as many Laptop or Notebook computers now come with inbuilt wireless technology. Disadvantages of Wi-FiWi-Fi connections can be unreliable, especially when working at a distance from a base station as the signal strength drops. Technology with similar frequencies, like mobiles and microwaves, can disrupt the connection, which means students may be disconnected from the Internet, or at least the speed of the Internet will be greatly minimised.Browsing and downloading speeds can also be much slower than a cabled connection simply because the speed of the Wi-Fi device is slower.Wi-Fi networks in schools are made to be easy for students to connect to, but by making them easy for the school children to log on, they also make it easy for Internet hackers. These hackers can put viruses onto the schools network and the computers logged onto the network, and they can also steal information from students and school computers logged onto the Wi-Fi server.Finally, battery life is minimised because of the extra power needed to connect to the network and Internet without cables. Final VerdictBBC News reminded the public of Karl Popper, one of the great philosophers of science, who said science is about falsification. You can prove theories and hypothesis are incorrect, but you can never prove they are correct. So, theories are innocent until proven guilty. And with no hard evidence to suggest wireless technology does negatively affect our health and the health of our children, the technology can only be considered safe.Further to this, BBC News pointed out that the television and radio modulated frequencies that come into our homes are just as powerful as Wi-Fi technology. If the journalists were so worried about the negative effects of Wi-Fi, should they also be worried about the effects of their own medium.However, the fact is that when it comes to children many parents and school staff will be concerned about the potential effects of the electronic smog created by Wi-Fi and will choose to play it safe by minimising, or even eliminating, the use of Wi-Fi within schools until more hard evidence is available.And while there are many other advantages for using cable technology over wireless (see the What are the advantages and disadvantages of Wi-Fi Internet Connections? section), perhaps schools should be using cabling over wireless technology even if it is in theory perfectly safe.