Month: June 2016

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Ice Thermal Energy Storage (TES) has the advantage of universal availability, low cost and transport ability through other system components. However, a conventional ice TES system for air conditioning application requires low temperature chillers and therefore standard water chillers must be replaced with low temperature glycol chillers which operate with a lower evaporation temperature and consume more power.

If we can offer designers an ice which freezes and melts above or below 0 ° C (32 ° F) these new products will open new horizons for environmentally friendly and economical systems for both New and Retrofit type process cooling / heating load shifting applications.

Phase Change Material (PCM) Eutectic solutions are mixtures of two or more chemicals which, when mixed in a particular ratio, have a freezing / melting point below or above water freezing temperature of 0 ° C (32 ° F) and they offer a thermal energy storage facility between -114 ° C (-173 ° F) and +164 ° C (327 ° F).

Eutectics are well-known and in fact early applications date back to the late 18th century however the separation and the life expectancy of these mixtures were unpredictable and therefore their wide spread usage was limited.

The disadvantages of a conventional HVAC chiller and ice (water ice) storage system can be overcome by utilising the latent heat capacity of various "Eutectic" mixtures without the need for minus circulation temperatures.

Phase Change Material (PCM) thermal energy storage not only enables the designer to utilise existing chiller technology but also enables charging by means of free cooling, ie without running the chillers

Although the term "Eutectic" is widely used to describe the materials we are interested in, a better description would be "Phase Change Materials" ( "PCMs"). Unfortunately, very few of the documented PCM solutions are true Eutectics and so many have to be modified to obtain a material suitable for long term use.

PCMs can be broadly grouped into two categories; "Organic Compounds" and "Salt-based Products". The fundamental requirement for a modified Eutectic (PCM) Solution can be classified in three categories, namely stable solution (no separation or degrading), minimum supercooling / heating and finally close freezing and melting temperatures.

There are three fundamental additives commonly used to modify hydrated salt based Eutectic PCM solutions. These three components are firstly Nucleating Agent which encourages Crystal formation and therefore minimizes super cooling and the secondly additive is Freeze Depressant to achieve a lower phase change temperature and thirdly Gelling / Thickening Agent in order to overcome separation and degrading problems.

Once the above components have been carefully applied, a satisfactory Eutectic PCM Solution can be produced from the physical and thermodynamic point of views and commercially available solutions offer a range of -114 ° C (-173 ° F) and +164 ° C (327 ° F).

However, majority of suitable PCM solutions for HVAC and refrigeration systems are corrosive to commonly used pipe and line components and therefore suitable encapsulation techniques must be applied to overcome this problem while providing the best thermal performance. Various encapsulation techniques such as tube, flat container or alternatively ball concepts have been developed whereby the PCM solutions are encapsulated in plastic and / or metal shell.

The heat transfer between the surrounding media, which flows around or inside the unit and the surrounding PCM solutions, takes place from the outer or inner or the combination of both surfaces of the encapsulated PCM unit. These techniques are generally eliminates the contamination risk and offers an efficient, cost effective, practical and flexible new type of TES designs.

Modern society's reliance on refrigeration and air conditioning indicates that refrigeration and the associated environmental issues will be with us for a considerable time and therefore one has to utilize existing and available alternative technologies with minimum usage of energy.

A Positive Temperature Eutectic Phase Change Material (PCM) Thermal Energy Storage (TES) not only provides the end user with an Environmentally Friendly design but also the following additional benefits can be obtained:

o Reduced Equipment Size
o Capital Cost Saving
o Energy Cost Saving
o Environmentally Friendly Installation
o Improved System Operation
o Flexibility for the Future Capacities

The temperature ranges offered by the proposed PCM solutions utilize conventional chilled water temperature ranges for both the charging and discharging sides of the system. Hence, they can be applied to any new or retrofit application with minimal technical and economical impacts.

Furthermore, the possibility of Free Cooling Cycle, Absorption Chillers, Co-Generation, Solar, Hot Water and Heat Recovery TES system combinations offer new horizons for designers to control the energy balance to match the load and electricity demand / consumption of the system as a whole.

The task for designers is to explore all available technologies towards achieving improved efficiency regardless of which refrigerant is used, and apply where and when possible diversification technologies in order to minimize the overall CO2 emission related to energy usage. Carefully balanced Eutectic A, City Phase Change Material (PCM) Thermal Energy Storage (TES) may be the answer for some of the cooling applications for an Environmentally Friendly and Economical alternative.

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Source by Zafer Ure

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Prefabricated building materials are used for buildings that are manufactured off site and shipped later to assemble at the final location. Some of the commonly used prefabricated building materials are aluminum, steel, wood, fiberglass and concrete.

Prefabricated metal buildings use galvanized steel and galvalume as the chief materials for building. Galvalume is a form of steel coated with aluminum-zinc. This is to protect the building against corrosion, rust and fire. It also provides a sturdy and protective covering to the prefabricated building. Almost all the components of a metal building such as beams, frames, columns, walls and roofs, are made of steel. Most prefabricated military buildings use steel or aluminum frames. Synthetic materials are used for the walls and roofs. To provide enhanced security, a combination of both metal and cloth materials are used. Plastic flooring materials can be quickly assembled and are very durable.

Prefabricated building materials used for small prefabricated buildings are steel, wood, fiberglass, plastic or aluminum materials. These materials are cheaper than regular brick and concrete buildings. Materials like steel, fiberglass, wood and aluminum are used as prefabricated building materials for sports buildings. These materials provide flexibility and are preferred for making structures and accessories like stands and seats for stadium and gyms.

For making low cost houses, prefabricated materials like straw bale, Ferro cement, Calcium silicate products, composites and other cheap wood based materials are currently being used. Calcium silicate bricks are strong and durable. Ferro cement consists of a cement matrix reinforced with a mesh of closely-spaced iron rods or wires. In this type of construction, the techniques used are simple and quick.

Using prefabricated materials one can make durable, water and fire resistant and cheap prefabricated buildings. Most of the prefabricated building materials are eco-friendly and affordable.

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Source by Jimmy Sturo

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A set of high quality mattress can be a big household expenditure but if it is looked after carefully, it ought to provide you with comfortable sleep every night for as long as 10 or 20 years. There are simple tips that can be followed to prolong the longevity of your $ 8,000 dollar mattress with advanced material technology such as individualized air chambers, thermostat controlled water bags, hypo allergic padding etc.

Most mattresses are damaged by doing things that should not be done on any beds, such as drinking and eating meals there. Luckily, there are also some remediation steps when you get careless and mistreat your pricey bed. These will help you avoid the painful consequences of having to throw away an expensive household item and getting negative thoughts such as vowing to only buying cheap mattresses in future such that neither your wallet or heart will suffer again when anything happen to them.

To take proper care of your new luxury mattress from either accidental drink spillage or normal daily wear and tear, the first thing you need to buy immediately is a good mattress protector that is laid on top of the mattress. The number one enemy of mattresses is actually moisture, which leads to mold and fungal growth as well as a load of other bacteria and microbes infestations.

The mattress protector helps to bear the grunt of such accidental abuses by forming a barrier between your mattress and the sources of external moisture. The costs for bedding ensembles and mattress protectors are pretty much insignificant compared to your luxury quality mattress and can be replaced without batting an eyelid when they get wet, dirty or torn.

In the unfortunate event whereby moisture gets into the mattress, how fast you perform mold remediation directly determines how much damage you can avoid. Firstly, wipe off any remaining fluid on the mattress surface with an absorbent cloth as soon as possible. Next, use a magic fabric cleaner thoroughly on all affected areas to avoid ugly stains, especially when red wine, coffee or pasta sauce is spilled.

After you have done all you can to minimize the stains, point a fan at the wet areas to dry them up. Do not use a hair dryer because some mattress materials can not withstand high heat and you may end up with deformed areas. Finally, pour some baking soda or sodium bicarbonate over the stains and leave them there for at least 12 hours. This will help remove smells and odors caused by the drink spillage.

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Source by Rodney Spence

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In the world of dentistry there are two front-runners when it comes to impression materials, yet which one would be the best bet for our dental surgeries? The two options we have are that of the traditional Alginate type materials and the more recent PVS (polyvinyl siloxane) silicone type materials.

When taking impressions of patient's teeth the most important factor is accuracy while other factors include ease of use, taste, and how long they take to set. Luckily both materials show strong results in each category but which one should we choose?

While both of these types of materials offer great benefits when creating dental impressions, which of them just about edges it over the other?

Alginate

As you might be able to tell from the name, Alginate is connected to that of Algae. In fact the particular type of algae that we are talking about is seaweed which is where Alginate is derived from. This type of impression material is one of the most commonly used in dentistry due to it being cheap, easy to remove, having a very neutral taste, and possessing a controlled working time.

It does have some negatives however; as the impressions can become distorted due to either an excess gain of water that can make it swell or a loss of water that can lead to it shrinking. This does not happen all of the time but when it does it basically means we have to start all over again.

Polyvinyl Siloxane (PVS)

The other popular type of impression material that is commonly used in dentistry is that of Polyvinyl Siloxane which is otherwise known as PVS. This type of impression material is available in light, medium and heavy bodies and is made by a number of manufacturers who have their own range.

The benefits of PVS include being hydrophilic and thixtropic, being extremely stable while offering excellent elastic recovery, being available in different flavors, and being tear resistant. The best part about PVS is that it gives you the ability to pour at your convenience.

Summary

Both types of impression material are able to provide accurate dental impressions and there is not much to choose between the two but it does seem that PVS is the best option. Being tear resistant and not being prone to water that can distort impressions gives it the edge over the more traditional Alginate materials.

PVS offers a better level of accuracy for those reasons above and should be the material of choice for most dental surgeries that are wondering what kind of impression material to use.

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Source by Rosario Berry

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Question: What types of materials are banners made ​​of?

Answer: This is a good question and is quite simple on the surface, although there are many variations within each category.

The two main categories of banner materials: vinyl (PVC) and fabric or cloth banners. That's the easy answer.

However, it is helpful to know the variations within each category, so I'll start with the vinyl banner category first, as it's simpler, I think.

First off, PVC or vinyl banners come to us as roll stock, and we either screen print (becoming less common), or digitally print these banners on a wide format digital printer.

There are several weights available, the most common being (at least in our shop) 10 oz., 13 oz., 15 oz., And 18 oz. The ounces refers to the weight of the banner per square yard of material. The heavier the weight, the more durable, although installation methods are often of utmost importance in the life of any outdoor vinyl banner.

With these materials, most are also available with a block-out layer between the sides that allows us to print both sides of the material without having a shadow show through the back side.

Another type of vinyl banners is the mesh vinyl banner, which is a perforated material that is printed with a backing sheet on it to prevent ink from spraying all over the printing platen on the digital printer. This material allows a certain amount of wind to pass through it, thus reducing the wind load from 10 to 20% on average.

The second main category is fabric banners, which are most frequently made ​​using polyester, nylon, or other synthetic fabrics. Most of these banners are currently printed using a printing method called dye sublimation printing.

Some street banners and cloth banners are also screen printed if the volume of printing justifies setting up the screens to do so, or the print shop specialized in street banners created by screen printing.

Dye sublimation digital printing of banners is one of my personal favorite advertising graphics to sell. It is very classy compared to vinyl banners, so much so that they have taken over the high end trade shows as the banner of choice, at least for companies that do not want to appear cheap.

The dye sub print process uses heat and pressure to transfer the CMYO print from the transfer paper to the synthetic fabric itself. Over the past few years, digital direct to substrate dye sublimated printing has started to take over the fabric banner industry because it has less steps involved in printing a banner using dye sublimation that the heat and pressure method. Ie, it's faster and cheaper to produce, so many printers are switching to this type of printer for those reasons.

Within the fabric category, the main differences you'll find is in the materials. There are dye sublimate printed satin fabric banners, stretchy fabric banners (polyester with Lycra or the like), outdoor polyester banners, acrylic banners, and nylon banners. There are polyester fabrics that are sheer, look like cotton, or any number of variations.

So, as you can see, there are many options for printed fabric banners available, whether they use the traditional dye-sublimation printing method or the DTS (direct to substrate) printing method. Or screen printing. Lots of ways to produce a fabric banner, and for interior use, I personally would almost always recommend dye sub printed cloth banners.

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Source by Barry K. Brown

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There was once a Navy Scientist who wished to design and build a US Navy fleet of submarines out of glass. Of course these subs would not be made of your typical household glass. Perhaps a metal type glass, which could withstand the pressure or carbon nano-tube sheets, which I have thought of myself. I can remember some Sci-Fi writers discussing underwater villages of aliens under the sea with clear construction materials, fun stuff to think about indeed. Yet we are now entering a age of new materials which where it may actually be possible, even likely that humans will attempt to build such things. Colonies under the sea, you see?

Perhaps we could design vortex flows to keep the pressure off the surfaces of the hull of the sub or undersea colony. Indeed, vortex creation would pull water away from the surface; movement maybe required at all times to use this principle for submarines. And you would need to put the underwater colony in relative fast moving underwater flows with vortex creation apparatuses up wind of the structure to get the water swirling. A simple fixed formation could accomplish this.

For submarines the blowing of air bubbles out as it moves might also be incorporated into the process to decrease hull pressure, which would also increase speed. Perhaps adding a wave energy wave creation feature when using materials such as carbon nano-tubes might be used since making the surface electrified would be easy. If we used such a concept also special coatings, which provide a gel formation around the boundary layer could be used as well. I bet there are 20 ways to do this really? And so we need to invest more research monies in exploring the mastering of the seas. Think on this in 2006.

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Source by Lance Winslow

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Sound insulation is not to be confused with sound absorption – they serve two different functions. This article covers sound insulation materials and the different types of sound insulation that can be used to effective reduce the transmission of sound energy.

When you soundproof a room you can either do it to reduce noise, which is nothing more than blocking sound waves by using distance or objects to block its passage; or you can use noise absorption, which transforms sound waves by suppressing echoes, resonance and reflection. The insulation materials have damping characteristics, which controls the sound levels, reducing and distorting them.

Sound insulation on the other hand is the prevention of the transmission of sound; a reduction in the transmission of sound energy to the adjoining air space. There are several different types of sound insulation materials that can be used to reduce noise and the transmission of sound.

A brief look at the different types of insulation materials will be helpful in making informed decisions for your home.

You can use fiberglass insulation inserted between the studs in drywall layers as well as foam insulation that can be blown into the wall without removing the drywall. The same methods can be used for flooring as well.

You can use the passive absorption method to reduce sound; mineral wood insulation or acoustic foam forces sound wave to change direction several time and travel a great distance before it can completely pass through the insulation material. Each time the waves change direction part of the energy gets absorbed by being converted to heat.

Lead sheets are very good at blocking sound transmission; in addition they are easy to work with, cut and install. Foil faced acoustic pipe wrap can be used to muffle sound from noisy pumps, generators, engines, saniflow systems, etc. Acoustic mineral wool is very useful in reducing airborne noise and can be used quite successfully in walls, suspended ceilings and flooring joists. The density of the material makes it an efficient sound absorber.

It is recommended that you do a complete research on the subject before attempting to use sound insulation materials.

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Source by Lawrence Cunningham

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My guides decided this month I should teach teach you how to work with trolls and gnomes. Post why? Because they are the caretakers and guardians of ALL material wealth and abundance on Earth. This is their job, and a purpose to which they are well suited. Very seldom does one spot a troll or gnome who is not grounded in material reality. Most know their task or purpose. Yes, I said material reality. Just because you do not see them, does not mean they are not there. They are all around you waiting to help. You need only to sincerely ask for their help. Have enough faith in what you've been told is improbable, according to your cultural beliefs, and your bottom line will improve.

Right now, panic is surfacing about material lack throughout the world. It is not just in the USA, it is worldwide. Even those who have enough seem to be suffering from emotional wobbles! Everywhere you see people losing jobs, losing money. Life savings are dwindling. Things are just falling apart, are not they? People are very frightened. For this reason, my guides were adamant I pass along this knowledge to help those in need of material and financial assistance.

There are much deeper reasons for this other than what is immediately apparent, but one of the REAL reasons is to teach us that there are certain beings who can help us right now! However we must ask them, in the correct way. The correct way is with food offerings we place out for them in return for any favors they bestow upon us.

We love to pretend beings such as trolls and gnomes are only myths. We are also a wee bit afraid of them too! We learn and buy-in to the craziest things from those who do not know truth! Culture has taught us to beware lest we get hoodwinked. We can trip if we believe in those silly fairy tales.

So what is the truth regarding trolls and gnomes? The truth is that if you have an honest need, then you'll receive help from them. Are you frightened you will not have a job? Frightened you will not have money to survive and provide for your basic needs? Trolls and gnomes can come to your rescue! These wonderful beings know all about how to bring what you most need into your life, when you most need it and lay it before you! They also understand how foolish it is to overlook their abilities to help humans in matters of material abundance and financial need. Trolls and gnomes have always had this gift or ability to help humans. It is us who have not seen, nor understood them or their purpose.

Trolls and gnomes are the guardians of material abundance. Yes they live underground but they also live above ground as well. Let us not limit them or their dwellings to what you read in fairy tales or myths. Recently I spotted a family of gnomes dwelling high on a snow capped peak way above the valley where I live. So much for tales in error. My Icelandic roots fairly cry out to ask them for assistance if I need it!

It does not matter where you live in the world, there are trolls and gnomes. Yes, they vary according to how they look and what they wear, just as we humans do according to where we hail from. They have customs and costumes unique to their lands. Surprising how like us they can be in that regard is not it?

"How then, do I ask trolls and gnomes for help" ?, you ask. Legends abound about how tricky and deceitful they can be, also how illusive. This is true, but one should always remember they also have a purpose, guarding and allowing only those deserving of help to take part in the riches of the Earth. The trolls and gnomes will not harm nor hurt you if you are honest in your dealings and come to them with true need.

True need. Pay close attention to those two words. True need is not spending wildly or lavishly on that which is not necessary to help you survive. True need is not two motorcycles in your driveway parked alongside two 4 wheelers, plus a monster truck sitting in your garage. True need is having a job, and enough money to put a roof over your head and food in your mouth. True need is the ability to protect yourself from the elements as necessary. It is not to dress in the latest style or fashion just because ….

How then is it trolls and gnomes relate so well to what we need? They are guardians of physical Earth. Gold is Earth based. How do we view gold? Gold is money. Money is gold. Money is closely related to dirt and rocks and stones. We find it in the ground. It vibrates to Earth. It grounds us. How many unhappy people have you seen that have access to plenty of money? Not too many. It is a circle of relatedness. Have enough money you feel grounded, solid and happy. Like it or not, this is a truth that many find hard to swallow. We need money to survive today. Yes, we are in the process of learning otherwise and to learn other uses for gold but for now, it's what we need to survive.

As a shaman, let me remind you not to be ultra spiritual or altruistic and say, "Oh but I do not care about money. I want what is best for me and my loved ones? I will always vote for the spiritual side of things and life. " Nonsense! You need to eat do not you. Pay the bills, and your house payment? Feed the dog and feel secure? (Say yes) Then you need money, ie gold. I love my higher self, but I also need the fridge to be full when I raid it at night. For that you need money to buy groceries. Trolls and gnomes have always known there would come a certain time when humans would turn to them for help. The time is now. Read on …..

Here is the way to ask for their help. It's so simple it may seem as if it can not be right or true but it is! Put out offerings and then ask for their help and PLEASE remember to say thanks at the same time.

The best offering is food you are about to eat yourself, because anything you would eat yourself is good to them as well. Place a bit on a plate and offer it. Do not forget to set out a beverage as well. You would not want to eat without something to wash it down. Neither would they.

I would suggest leaving it for a few days or through the day, and then you can place both the offerings and drink outside to let the birds and animals dispose of them. Never put offerings in the garbage. Always place them outside and let the birds and animals help you recycle.

Many people who receive readings from me know I am famous for suggesting food and drink offerings to their guides. In the case of asking for help from trolls and gnomes, it is no different.

Most beings who can help you are just like you and I …. they love to be recognized and asked to help. They also like to eat. It is well known in many cultures that they can partake of the essence of the food and drink!

The key here is to believe and you will receive. Do not worry how, or why, or what or even when. Just know you'll get the help you honestly need, when you need it. Yes, I am asking you to set aside your ideas of what is possible and just ask and offer, and say thanks.

In this time of seeming scarcity and lack in the world, do remember to call on the beings who can most readily help you with your material needs. In this case, that would be trolls and gnomes. It is one of their purposes to assist mankind. I know, we all have angels and guides. We always ask for help from our guides and angels or at least I hope you do. This is special. Here we are discussing having a direct interaction with trolls and gnomes. Post why? Just because it is possible and it works! In this time and place, they have a special service to impart to us humans. They always have, but most tales, till now have made them pretty inaccessible, which is nonsense.

Do not make this harder than it has to be. Do not add any elaborate prayers or rituals to this. Asking and offering plus a respectful thanks is enough. If it looks as if I am repeating myself, I am. Offer, ask and say thanks! Three important keys plus belief. What others would view as miracles is really just knowledge given that we can speak to and have a respectful relationship with the trolls and gnomes.

One poignant memory of mine is a day trip I took with my beloved mother just before she passed beyond the veil. We were taking a Sunday drive to a neighboring rural community. As I drove, she ate her cheeseburger and drank her coke in silence and enjoyed the scenery. All of a sudden, as we approached a huge farm on the main drag through town, she shouted, "Look Salome! Three Billy Goats Gruff! Look!"

There they were in a pasture next to the farmhouse. Three goats, standing there in all their glory. One huge ram with a huge rack of horns, a ewe and a younger goat. As I scanned the scene, not far from them stood a proud bunch of trolls talking amongst themselves. My mother brightened and laughed as she said, "Look at the trolls too! Now Salome, you can be sure that is one finely run farm. Just look at that house, the barn and the land. They are so well kept. Those trolls are making sure everyone is happy and well fed. "

True to my family's teachings, I had to chuckle at her choice of words and agree because I saw real truth before my eyes. Also true was the knowledge those keepers of that homestead knew the power of working with beings such as trolls and gnomes. That the owners put offerings out to ask for help and honor those beings who could make a difference, as needed, I have no doubt. In this case, the trolls. The three goats? They looked fat and happy to be sure. A funny story but nonetheless very true!

One last thing I would like to add here for you to think about is this: There are many who will see this advice and think oh no! How could Salome even suggest going to them for help? How nuts is that? To them I would say that I have learned the ways of the trolls and gnomes from my family. As a small child growing up, there were times when I watched my father ask for help from them, if needed, for his family and his farm. His needs were always honest and respectful. Never did I know him to ask for help from trolls or gnomes if it was not truly needed. He showed respect. And he always said thanks. Always. My family was always mindful of spirits who oversaw the farm. I was taught to respect their right to live there and to know I could ask for help if I truly needed it!

So, if you're worried, or fearful you will not get your needs met in these dire times, remember the trolls and gnomes. They guard material abundance and they dole it out as well. If these techniques seem odd or funny to you at first, keep trying. Make food and beverage offerings. Practice makes perfect, as they say, and you will produce results if you truly do need help. Who knows? You may even be graced with these wonderful beings showing themselves to you in the flesh. What fun! It could happen. After all, they are in charge of the material and physical world we live in.

I have many stories of working with trolls and gnomes, and while this is only one simple method of how to work with them, it is an important one, because they really can help you survive these supposed tough times.

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Source by Salome Jacobsen

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There are different types of speakers out on the market today. Finding out what you exactly need may save you some money, but more significantly, improve the sound system of your car. Read on to learn more about the different types of car speakers available to you!

Coaxial Speakers

This type of speakers is the most common. Factory installed audio system usually install at least two pairs of this type in new vehicles. It's basically a midrange cone woofer with at least one tweeter mounted right on top of it. The result is a low to midrange sound reproduction from the midwoofer, as well as having high frequency reproduction from the tweeter.

Older cars usually only have the midwoofer without the tweeter attached to it. As car makers realize the significance of car audio within the last couple of decades, they improved factory-installed systems with coaxial speakers. Do not be fooled by car makers today who say their car features a 6-piece speaker system because the four speakers are generally midrange woofers, with speakers 5 and 6 being simply detached tweeters. Unless it is configured as a component system (explained below), comes with a factory-installed amplifier or subwoofer, you could not call that 6-piece system premium audio; and therefore you should not pay extra for something you would otherwise already have.

Additionally, coaxial speakers are normally described as 2-way, 3-way, 4-way, etc. speakers. Simplistically speaking, a two-way is one woofer with one tweeter attached to it. A 3-way adds another tweeter, and so on and so forth. You may ask why is it that it even needs a tweeter and to that I will explain.

A typical non-tweeter speaker will pick up around 15-10000 Hz (remember low frequency means more bass). Regular source units like CD players put out a full range sound, like everyday noise that you hear from 20-20000 Hz. Without tweeters, your system will attempt to reproduce that missing 10000 Hz with something it physically can not do. The result would be not only a missing high-frequency sound but also additional distortion or degradation to the overall sound quality of your system.

Tweeters allow your system to reproduce the otherwise impossible sound, giving you a much clearer and defined sound quality. Any additional tweeter adds more detail to the sound as it hones in on a particular range.

Component Speaker System

A component system typically includes midrange woofers, separate tweeters, and crossover filter networks. What is explained above concerning midwoofers and tweeters apply the same as component systems. The only difference, as you may have noticed, is the separate tweeters. It would function the same exact way as the coaxially mounted tweeters, except for the crossover filter networks.

These filters improve sound quality significantly by channeling only audio signals the different components could physically handle. For instance it would channel only high-frequency signals (10000-20000 Hz) to the tweeters and the lower frequencies (25-10000 Hz) to the midwoofers. The result is an even better sound quality because each component is not given signals that they could not physically reproduce.

Component systems tend to be significantly more pricey but with much improved sound reproduction. Additionally, you generally will not find 3 or more way component systems because it is unnecessary, thanks to the filter. This is why I said that factory installed audio systems would only be premium if a crossover network is present.

Cone and Surround Material

The material of the woofer or the tweeter plays a significant role primarily in their longevity. Sound quality is only as good as the entire construction (ie voice coil type, magnet size, etc.). Though denser cones (Kevlar, glass fiber, polypropylene) tend to produce better sound quality than thinner materials (cloth, paper), understand that it takes the whole construction to produce great sound so do not dismiss a set of speakers just because it has thinner cone material. Heavier or denser cone materials last longer, especially helpful with constant high-power outputs.

Just like cone material, surround material plays a significant role in the longevity of your speakers as well. In its most simple explanation, a cone must move up and down as it produces sound. Think of your speaker as a trampoline, with the center elastic material of the cone and the springs on the edges as your surround. The surround must be tough and be able to stretch a little bit. Once again, denser material would do much better as thinner material tend to fray and degrade over time. LOWER-end the Most car audio speakers have foam color : as the surround material, but these Tend to harden the crack and after temperature changes-Which Occurs in your car in the summer and winter with heater or air conditioning (Especially under direct sunlight).

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Source by Armand Jusuf

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Typically, you will find 7 sorts of materials used to produce canoes. Each distinct material has its benefits and drawbacks and you need to learn a little about each for making the best choice.

1. Fiberglass Canoes
Fiberglass canoes are probably the most common canoes available, but buyers beware: Fiberglass quality ranges from perfectly to extremely, bad, and the unlucky thing is the fact that you can not always determine the quality simply by the price. A great fiberglass canoe is built by laying strips of fiberglass textile into a mold soaked with resin. Poor-quality fiberglass canoes are produced making use of small, independent bits of fiberglass called "chopped fiber" instead of the stronger, more pricey fiberglass fabric. Fiberglass is extremely lightweight, which works well for fishermen as well as paddlers.

2. Aluminum Canoes
Aluminum is a rough, long lasting material that is low maintenance. Aluminum canoes usually are low in cost, and they are the only type of canoe you could leave out all winter without worry about degradation. The disadvantages of these kinds of canoes are that aluminum is a heavy material, and the delicate metal has a tendency to stick on rocks.

3. Wood Canoes
Wood is possibly the most eye appealing of all the materials, nevertheless it has constantly been the least durable. On the other hand, modern-day canoe builders making use of wood to build their boats have access to scores of things that did not exist even 20 years ago. Water-tight epoxy films, varnishes, along with contemporary manufacturing methods have made today's canoes quicker, lighter in weight, plus more durable then ever previously.

4. Royalex Canoes
Royalex is a substance created by sandwiching the foam core between layers of ABS substrate and completed using a vinyl coating. The difference between Royalex and polyethylene design is basically weight alone, since Royalex is the lighter of the two. However, remember that Royalex is also higher priced as well as weaker than polyethylene. It is an outstanding choice for paddlers that require a serious canoe capable of tackle whitewater but that need something light-weight for transportability.

5. Kevlar Canoes
Kevlar is quickly becoming one of the most well-liked choices for canoes for a couple of reasons: Strength as well as weight. Kevlar may be used to produce a very lightweight canoe that is as strong as steel on a strength-per-weight ratio. These canoes are usually designed for flat water, for example lakes, and really should not be used in rapids or whitewater. Additionally, Kevlar is usually quite expensive.

6. Polyethylene Canoes
Polyethylene is extremely tough, although not very rigid. The most successful solution is a trademarked "sandwich approach": A thick foam core is sandwiched between an external and internal layer of polyethylene to offer stiffness at reasonable cost. Polyethylene canoes slide off sunken rocks and pop into shape better than aluminum canoes. People demanding toughness or serious whitewater paddlers usually choose good quality polyethylene canoe.

7. Carbon Canoes
Carbon is the most recent development in the world of canoeing and is glued with Kevlar to create canoe material. Carbon is lighter, firmer, and less adaptable than Kevlar is allowing it to maintain its shape better than many other materials. Whilst lighter than Kevlar, carbon is not quite as durable, however it is a good material to select when weight without having to sacrifice too much of strength are components of your choice.

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Source by Terje Brooks