Monday, July 10, 2017
By employing a trick normally used to cool high-performance computer chips, IBM researchers have found a way to make concentrated photovoltaic cells that are more efficient in converting the sun’s energy into electricity.
The researchers have shown that it is possible to increase the concentration of light on photovoltaic cells by about ten times without causing them to melt. This, they say, makes it possible to boost the amount of usable electrical energy produced by up to five times.
IBM is not known for its work in solar energy, but that has changed recently, with the rising cost of fuel and the growing interest in renewable alternative energies, says Supratik Guha, lead scientist of photovoltaic research at IBM’s T.J. Watson Research Center, in Yorktown Heights, NJ. “About a year and a half ago, we decided to start looking at photovoltaics,” he says.
The principle behind concentrated photovoltaic cells ( for example: GOAL ZERO NOMAD 100 ) to use a large lens to focus light onto a relatively small piece of photovoltaic semiconductor material. The benefit is that only a fraction of the semiconductor material is used, thereby reducing costs.
There are a number of companies marketing such technologies, but one of the main challenges is in coping with the vast amounts of heat produced by the focused sunlight, says Guha. “You’re really heating the chip up. As you raise the temperature of the chip, its efficiency drops, so you’ve got to keep the temperature down.” There are generally two ways to do this: either by using passive heat sinks–metal blocks that draw the heat away from the cell–or, for higher-temperature systems, by using water cooling, in which water is pumped through a metal heat sink to draw the thermal energy away more efficiently.
In many respects, this is a problem very similar to cooling computer chips–something with which IBM has a long history, says Guha. State-of-the-art chips now kick out about 100 watts per square centimeter, which is similar to what concentrated photovoltaic cells have to endure, he says.
So Guha adapted an IBM-developed material currently used for chips to improve the heat transfer between the photovoltaic cell and a water-cooled heat sink.
“If you place the chip on a copper heat sink, the interfacial heat transfer isn’t good enough to keep the temperature down,” says Guha. This is because microscopic indentations in both surfaces means that there will be relatively little surface contact between the faces. So photovoltaic companies tend to use various organic pastes to act as thermal interfaces. The problem is that such materials aren’t particularly efficient at transferring heat.
IBM’s solution is to place an ultrathin layer of liquid metal, a compound of gallium and indium, between the two surfaces. “The main benefit here is that it’s a metal, so it has a very high thermal conductivity,” says Guha. And because it’s a liquid, it is possible to make this layer extremely thin, typically around 10 micrometers.
Using this simple solution, Guha and his colleagues have demonstrated that they can focus the equivalent of 2,300 times the sun’s natural energy on a one-centimeter-square photovoltaic chip. Without cooling, this would melt steel, he says. The photovoltaic cell temperature would be in excess of 1,500 °C, and therefore would simply vaporize. With the liquid metal and water-cooling system, the IBM photovoltaic material remains at 85 °C.
“I’m sure there will be interest from [concentrated photovoltaic] companies, and it’s definitely something we would want to investigate,” says Stephen Bates, CEO of Whitfield Solar, in Reading, U.K. “But it would have to be exceptionally low cost because the industry is so incredibly price sensitive,” he says.
However, despite the promise of this approach, IBM is not planning on branching out into the solar-energy market. “We don’t plan to make [concentrated photovoltaic] systems,” says Guha. Instead, IBM is in talks with solar-cell companies about licensing the technology, he says.
Wednesday, April 5, 2017
Buying a Used Rolex Watch can save you thousands of dollars off the new retail price. However, one must be careful since there are many fakes out there, as well as some dishonest sellers who misrepresent the description of the watches on their websites. I have created this small guide to assist with that problem. If you follow these steps it will greatly diminish the chances that you will make a bad buying decision.
There are several things that can be done to make a better purchase. However, the most important ones are: check seller's reputation, inquiry for model number, ask for first three digits of serial number, and require more pictures if available.
It is very important to check for the seller's reputation since in that way you are already avoiding possible scams. If you are planning on buying your item on eBay you should check the seller's feedback , not only the total and percentage of negatives but seller ratings in stars. I would advice that you buy from sellers who have at least 95 % or more and a 4.5 rating or better. If you are using a search engine it is good to know how long the website has been online and see if you can find more about the website . Also it is useful to know if the company has very well explained policies because the most serious companies do have one. Among the things that need to be checked on the policies are if they have a refund policy and a warranty policy . It is always good to know in case that you do not like the timepiece that it can be returned, or can be fixed at no charge in case it stops working. It is good to ask questions by sending e-mails since you can keep a record of everything; however, it is always a good idea to call before closing a deal.
When you are ready to buy your pre-owned Rolex watches You will need to do some research and find out which is the model number that you are looking for. Then You will have to ask the seller what is the model number of the watch you have interest to see if it matches. The reason for that is that some sellers customize watches in order to make customers believe they are buying a newer watch. For example, let's say that you are interested in buying a Rolex Date Sapphire Crystal Stainless Steel Quick-Set. You would then do your research and find that the model number is 15200. You then go to a website and look at some pictures and the seller describes the watch as a Date Sapphire Crystal. In reality what you do not know is that the seller posted a model 1500 Plastic Crystal Non-Quick and customized it with sapphire crystal. In other word the seller is offering a much older watch making you believe that the the price is great when it is actually expensive.
The first the digits of the serial number will help you decide what year the watch was fabricated. Therefore if you have to decide for example looking at pictures between two watches that look similar and about the same price then the serial number would be a good deciding factor. For instance if you have a watch R86XXXX(1988) and a S73XXXX(1994), then the second would be the best choice.
In some cases sellers only put one picture of their watches, then it is a good idea to ask for more pictures including one of the back case, of the bracelet, and the movement. Since you do not have the watch in your hands it would be the best way to get a feeling of how good condition the watch is in. Please also make sure that the photos listed are pictures of the actual watch and not stock photos.
With some time and patience You should be able to save thousands of dollars on a beautiful timepiece that will last you for decades. Just follow these steps and You will be more confident in your purchase.
Tuesday, March 28, 2017
SEO or search engine optimization is the most popular strategy that all digital marketers are applying today. Entrepreneurs and webmasters spend a fair amount of money to optimize their websites for SERP.
This is because many visitors on the internet still use the search engine to look for products and services. Consequently, businesses want to take advantage of this fact by doing everything to divert such visitors to their websites. However, it is easier said than done.
Creating a website and expecting it to appear in the search results don’t work how you would expect work. In fact, even those who are able to optimize their websites still worry about the end result. This shows us that SEO is an important strategy that needs to be done correctly to ensure the best results.
Some of the best search marketing services Kansas City specialists, have shown the five best ways to cut costs with SEO, and today we will be covering these. Let’s get started!
Improve the Speed of Your Site
One factor that makes a site rank high in SERP is site speed. The algorithm does not favor a site that loads very slowly because it drives away visitors. Google wants every site to load faster to avoid the bounce rate that reduces the rank of a site.
Monday, March 13, 2017
Trying to bring in new customers can be a really difficult task that requires you to expand your marketing budget. But, what if it were able to engage existing loyal customers to bring in the new ones? This is the premise behind work-of-mouth marketing. If done right it can help you expand your customer base and increase sales, without spending a fortune on marketing. Several companies have employed this technique successfully. Even small business owners can deploy this marketing skill to grow their business. Continue reading to find out how:
Get Customers to Leave Reviews
The best way you can use your loyal customers to bring in new ones is by asking that they leave customer reviews. Consumers always look at reviews when buying products or choosing services. They want to know that they’re spending their money on something of value, and something they can trust. So, get your loyal customers to leave reviews and tell people how great your business is. A great way to do this is by leaving Google Reviews. This means that when your business appears on Google, it will have a star rating out of five. Get those five stars, and you’re more likely to see new customers come flooding in as they think your business must be great. Encourage customers to leave reviews at every opportunity. Have a section at the bottom of your site where they can leave reviews. Or, whenever they pay for something online, on the transaction confirmation page you could have a call to action that gets them to leave a review.
Wednesday, March 1, 2017
Reputation is everything when you run a business. If you have a bad one, it will lead to a whole host of negative issues. However, a good reputation can help drive your business forwards and help you gain more customers.
As such, building a good reputation is key, and there are many ways to do this. One of the best ways is to make your business more environmentally friendly. Doing this improves public perception of your company and can also lead to additional benefits. So, here are five easy ways you can become a more environmentally friendly business: