How solar gain can be both a blessing and a curse, depending on the situation.
When you have any large expanse of glass creating an enclosed environment, you will see the phenomenon of solar gain. This is where the interior space heats up above the temperature without any other source of heat. The reason is to do with different wavelengths of radiation. Glass is more transparent to some than others, so heat bouncing back of surfaces doesn’t escape. Added to further heat from the sun, this causes the temperature to rise.
There are pros and cons to this. One of the most obvious practical uses of solar gain is for gardening, where greenhouses and polytunnels are frequently used to raise plants. Here, solar gain allows for warmer temperatures inside the greenhouse, which helps plants grow more quickly. It allows us to grow seedlings earlier in the year, protect plants from frost when they are not suited to our climate and grow plants which otherwise wouldn’t grow in our country because the temperature never gets high enough.
However, even with a greenhouse, solar gain can sometimes prove too severe, drying soil and scorching plants. This is why they tend to feature windows or other forms of ventilation, so that the temperature can be controlled in the height of summer. Many people also ensure that their greenhouse is positioned so as to never receive direct sunlight in the middle of the day to prevent extremes of heat.
A similar thing can be seen in large office blocks, particularly skyscrapers, where one whole wall might be glass. Here, solar gain can make life unpleasant for employees, raising temperatures to unbearable levels. Air conditioning systems are often used to combat the effects, but this can prove rather costly. A cheaper alternative is to have some sort of solar heat gain reduction film applied to the windows. This can minimise the effects and therefore reduce a firm’s carbon footprint by minimising the need for air conditioning.
Solar gain is also used deliberately by some architects to minimise heating bills. By having glass walls and windows positioned so as only to be struck by direct light during the winter months, when the sun is lower, the effects can be felt when they are needed, but not at other times when increased temperatures would be unwelcome. It takes careful calculations and thoughtful design to achieve an effect like this and so it is rarely seen. However, it is an intelligent way to make use of a natural heat source and can prove greatly beneficial for residents.
Malcolm Penfold writes on behalf of macrovitro.com
A summary of what mercury is and how it’s been used over the centuries.
Mercury is one of the powerful elements on the planet, however it is not really given the credit it deserves. This highly usable element with its near indestructible properties has been used by early civilisation for all sorts of reasons.
To start with mercury sits in the D-Block section of the periodic table. It is a heavy, silver type element and has been given the nickname quicksilver. Previously the Greeks named mercury ‘Hydragyrum’ which derived from Greek ‘hydr’ meaning water and ‘agyros’ meaning silver. It is one of the only metals that can stay in a liquid state when in standard temperature settings (room temperature which is around 27-28°C). It has a freezing point of -38.83°C and a melting point of 356.73°C giving it one of the narrowest temperature ranges on the period table.
Mercury is not a material that can be harvested or replicated. It is often hard to find and can be irritable if it comes into contact with human touch. Normally mercury is found in deposits of cinnabars. Cinnabar is an ore of mercury which means it has the perfect properties to hold mercury inside its core without changing its state, altering or damaging the element. Basically Cinnabar is the perfect blanket for mercury.
Now strangely mercury has many uses but perhaps the most common is use is in thermometers and temperature sensors. However mercury is also found in other measuring equipment such as barometers, manometers and float valves. It is also used in florescent lighting.
Mercury was also used as a binding agent in cosmetics during the late 20th century. It was a popular material during the 60’s-90’s and was in high demand. However the effects that it had on the human body were at that point not very well known. The effects of being exposed to mercury became a lot clearer after years of being used as women began to die of mercury poisoning over extended periods of time. Because of this mercury was banned from being included in any cosmetic product in 1998.
Mercury also found its way into fashion, as in the 1800’s gentlemen’s hats were lined with mercury to give them a firmer structure. However it was soon banned as gentlemen began to die from the then new condition of mercury poisoning.
Mercury was also popular with art lovers over the centuries and was used for many decorative and artistic purposes.
So if you ever wonder what that strange liquid is in your thermometer, remember how important it really is and how much it has helped generations.
This blog about mercury was written by Gemma Franks, a temperature sensor technician who realises the value of this important element. She uses http://www.cacheuk.com.
How forensic science has changed the face of criminal investigation.
One hundred years ago solving crimes a lot trickier than it is today, and most of the time the perpetrator of the crime was never caught. Cases such as that of Jack the Ripper may have been solved if today’s techniques could have been used. This case still remains unsolved and to this day criminal investigators and forensic scientists are only now beginning to find fragments of evidence which are helping to solve the case, or at least coming to some sort of definitive conclusion.
Forensic science may sound very technical, however it is the science behind solving crimes. A Forensic scientist will use different techniques such as DNA analysing and profiling, blood stain pattern analysis and criminal evidence analysis. These kinds of techniques can be applied to crime scenes as many of them have been adapted to be used in multiple situations. Forensic investigators are now required to visit all kinds of crime scenes and process different kinds of data and evidence. They are also required to interpret data gained via computer sequencing and DNA analysis, meaning high levels of skill and an impressive understanding of the field is imperative.
Forensic scientists can be hired by different kinds of people, but most people have the perception that forensic scientists only work for the police, a point which isn’t true. Forensic scientists are hired by legal representatives, government agencies and by private individuals.
Careers in forensic science in the UK are less popular than in America. The crime rate in the USA is double ours, especially in areas such as homicide and drugs. These are areas are where forensic science shines as these criminal fields often require the most analysis and rely heavily on exacting evidence.
To become a forensic science you have to plan early and be really driven to make it into a career. Biology, chemistry and economics are normally the type of subjects that can lead you into a career in this field. Universities all over the world provide forensic science courses and will offer different roles in the field as part of your placement whilst on the course. From this you can establish yourself in the field and build a well rounded career in forensic science. Many professionals choose to take their study further and gain either a Dr or PHD.
Forensic science is one of most challenging and demanding career paths to choose, but it’s also extremely rewarding.
This article was written by lsiah Chung, a trainee forensic scientist. He’s often used www.forensicequity.com as a resource.
In what can only be described as a strange turn of events, recent DNA testing completed on ancient Aztec remains show that once the tribe conquered an area, their very genetic make-up changed. The study, published by the American Journal of Physical Anthropology, based their findings on DNA samples extracted from remains that were in a specific area before and after an Aztec conquest.
Brief History Of The Events
The Otomi people were an indigenous tribe in Mexico in the Xaltocan area. This city saw much turmoil prior to the Aztec invasion in 1395. A large majority of the population moved from the area prior to the invasion, but the city was still considered populated when the Aztecs arrived.
According to records from European settlers at the time, the Otomi people abandoned the city upon the arrival of the Aztecs. Afterwards, the Aztecs populated the city with their own people. The Aztecs remained the rulling class of this area until they were finally defeated by the Europeans that were steadily coming into the area.
What The DNA Tests Discovered
Anthropologists were able to locate remains from residents of this area from before the conquest and some that were dated about thirty years after the invasion. They extracted DNA samples from the bones and teeth of the remains and performed mitochondrial DNA testing. This type of testing can trace the DNA through the maternal line.
What they discovered is that the remains from prior to the invasion were relatively the same, while thirty years after the invasion there were significant differences in the DNA make-up. There could be several reasons for this to have occurred.
The anthropologists believe the most logical reason for the change in DNA lines is that land and possessions passed down through the male side of the family in Aztec civilizations. This would justify why the maternal lines are so varied in such a short period of time.
Another possibility is that the Aztec captured females from other areas and brought them to this area as mates for their warriors. Again, this is just speculation at this time.
A final thought is that the Aztec line is so different than the indigenous line that the second set of remains are just not connected with the older set found that are confirmed to be from the Otomi tribes. This cannot be confirmed until the paternal DNA line is researched.
The anthropologists stated that DNA testing must be conducted on the remains to see if they can further establish the reason for such a drastic change in the DNA sequencing found in these two sets of remains. At this time, however, the researchers have not been able to collect viable paternal DNA samples from the remains.
Image Credit: rageforst
- License: Creative Commons image source
Derek is a writter for GTL DNA, a market leader for genetic and paternity testing.
The use of dust control systems is on the rise as more businesses look for ways to make the workplace conducive and free of air particles. If not eliminated from the air, these particles can cause diseases and affect the productivity of employees and in the long run, profitability of the business. It is for this reason that many organisations are investing in high tech dust control systems.
There is a wide variety of dust control systems available and as such it is important to consider several factors prior to buying one. Therefore, it is important to understand how a particular system works so that you can decide if it will work for you or not.
Electrostatic precipitators work by separating dust from the air entering a building, by using electrostatic charges. The air containing the dust is then vacuumed into the control system. It then passes through a filter mechanism, where positive and negative electrodes cause the air particles to attach to the collection plate. After the removal of the dust particles, clean air goes through another filter and is directed to the room.
Another type of dust control that you might consider buying is the one that uses media filtration method to filter dust from air stream. To do this, it uses a fabric or a screening material placed on the direct path of the stream that traps dust particles. As more and more dust particles are trapped, a “dust cake” forms and this in turn traps more unwanted air particles.
Single Or Multiple
On the market there is both single and multiple dust control systems on offer. Having a single or centralised dust control system will allow you to save energy costs as the system uses fewer blowers compared to multiple systems. Moreover, the cost of installing a single system is much lower compared with a multiple dust system that will require several airlock feeders, hoppers and duct work. The other benefit of a single system is that is has few filters that need to be changed occasionally thus you will not need to spend time and money on replacing several filters as it is the case with multiple dust systems.
The dust collection systems are available in several designs, thus it is possible to find one that matches the décor and design of your premises. With such dust control systems, you do not have to worry about the health of your staff being affected by a dusty or dirty workplace.
By Sarah McDowell, writing on behalf of http://www.aerotherm.co.uk/a leading engineering company specialising in numerous industry sectors including; automotive, food and oil as well as dust extraction system design and fume abatement systems
Engineering is a very technical field. However, the key to managing a good engineering team goes beyond the technicalities. It includes capitalizing on your team’s skills, get valuable feedback, praising people in public and leading by example. If you want to achieve superior results you must be willing to put forth superior effort. Here are six tips for building a high performance team:
Log positive and negative events
Nothing promotes team moral better than recognizing achievement. Likewise, addressing performance issues can be detrimental from individuals and teams. Focus on daily achievements and find opportunities where team members can exceed expectations. Use technology to keep track of both good and bad occurrences throughout the week. If possible, have weekly one-on-one meetings with each team member. This will keep the team focused and on track to exceeding goals.
Get feedback from peers and co-workers
For managers, it can be hard to assess the progress of your direct reports, especially is you useAgile methods. While it may seem like someone is struggling at work, it’s hard to decipher where he or she needs guidance or what skills need to be sharpened. Therefore, a great way to measure the performance of your engineering team is to conduct peer reviews. In addition to measuring technical skills, you can gauge practical skills like communications, teamwork and leadership.
The most difficult obstacle for any manager is deciding with whom to spend your limited amount of time with. Should you use a chunk of your time helping out the lower performers or should you spend time cherishing those who are outperforming their peers? As much as you would like to help those who are struggling, the ones who have earned your time are your best performers. With that said, it’s important to cherish your top people. Give them your time to help them exceed their goals.
If one member of your team is continuously not meeting expectations, you owe it to them to find a position in which they can be successful and attain a fruitful career. That may include placing them in another role at the company, or even another company altogether that has a more appropriate role for them. No one wants to feel like a failure. Make it clear that you are helping them to achieve their career expectations. Leaving someone to flounder hurts both the team and the individual.
Make praise public and criticism private
Most engineers are motivated by opportunities and learn through recognition. While money is a necessity, it’s not an appropriate motivating factor. Praise and recognition costs nothing, but it can generate a substantial amount of good behavior. Contrarily, no one should be humiliated in public. As a manager it is important to recognize these situations. If someone is having a performance issue, address it in private. But, if someone is exceeding expectations, public praise is necessary.
Lead by example
The worse kind of leader is one that sits back and lets its team make mistakes. It takes a brave leader to be in the trenches with your team and deal with the different situations that come about. When your team is encountering problems, it’s important to jump in to help solve the problems. You also want to make sure that your team is empowered with the right resources, authority and backing to help them prevail. Managers that issue orders and do not get involved do not gain trust, respect or results. It’s always best to lead by example.
- License: Creative Commons image source
Jamie Aldson is a freelance writer and engineer at a custom extrusion technology company. The company is the manufacturer and distributor of T-slotted aluminum extrusion and accessories to both commercial industries and individuals.
Is Dial up Internet still relevant?
Dial up internet was the way to go two decades ago when the internet first started to take off. Believe it or not, dial up still exists. Dial up services are still available in most areas of the world and are the main source of internet connectivity when wireless and optical ethernet services aren’t accessible.Even in vast parts of developed countries, like the United States and Canada, there are dial up subscribers.
Cheap, safe and secure
Dial up internet is still one of the cheapest ways to go when surfing the web. It does have its drawbacks, however. It is much slower than the newest forms of wi-fi and optical ethernet. It is relatively safe when compared to other forms of internet. It is harder to hack into and does not have the safety issues wi-fi users may be subjected to. Dial up is also safe because you have to ‘dial in’ to a routing office. This is opposed to many DSL, Cable, and wi-fi connections where you are always connected. If you are always connected, this leaves you information open to hackers around the clock.
Individuals who choose to use dial up normally do so because they have no other option. Telephone and cable companies don’t want to invest in hardware to bring high speed internet out to individuals in rural areas. Therefore, many rural customers will pay premium prices for dial up internet, simply because nothing else is available to them. However with the introduction of high speed internet connections, people can perform searches in a matter of seconds compared to the minutes and hours it takes with dial up. Downloads can take several hours using a dial up internet service. With DSL and wireless internet connections, users can download even the largest of files in a matter of minutes.
Should you make the jump to high speed?
Choosing to make the move from dial up to the newest advancements in technology can be cost effective and convenient. No more waiting while the number is dialed and the computer is connected to the internet service. DSL and broadband internet provide the user with fast, effective internet service. While high speed internet services are more expensive than conventional dial up internet, they are well worth the price. The convenience and benefit of real time searches and the addition of online security features makes browsing the net easy.
It also saves time and allows you to get on with other important aspects of your on-line and off line life. Some DSL packages start as low as $15 a month and can be pennies over the cost of dial up service. This being said, if dial-up is seemingly your only option, try contacting a satellite Internet provider.
Eric Kuhn is an expert in the field of high speed Internet connections