Android 2.2 Froyo

Android OS 2.2 or called Froyo has a lot of progress from the previous generation. Android OS changes Froyo with previous OS:

A. Performance & Speed: Various test results of benchmark test Froyo faster and stable.

2. Flash support: Easily show videos and games directly from the phone default browser.

3. Supports Microsoft Exchange: There is a calendar synchronization, remote wipe, auto-discovery and other Exchange features.

4. WiFi Hotspot: One of the advantages Froyo, which allows the phone to be the source of a wireless Internet connection for up to 10 devices.

Excess Android 2.2:

-Multitasking:

Android device can run multiple applications at the same time

-Ease:

There is a notification on the Home Screen Android phone to SMS, Email, RSS Reader that there is a new article,

Easy-Access:

Easy access to Google’s Android App Market.

-Cell phones are more and more options:

Users can freely choose according to preference Android phone.

-It can install a modified ROM:

a costum ROM that can be used on Android phone users to change the look of the default Android.

-Widget:

User to easily access a variety of settings quickly and easily with the widget.

Shortage of Android 2.2:

internet connection-continuous:

Almost all Android devices require a constant internet connection.

Ad-free applications:

In the Android App Market for free applications available, but in each application, there are ads below and above the application.

Android version 2.3 (Gingerbread)

Latest OS Android was launched on December 6, 2010. Changes obtained from the Android 2.3 Gingerbread:

A. increase the ability of the game (gaming).

2. improved copy and paste function.

3. screen interface (User Interface) redesigned.

4. support for VP8 and WebM video format.

5. new audio effects (reverb, equalization, headphone virtualization, and bass boost).

6. ability to support Near Field Communication (NFC).

7. support amount is more than one camera.

Excess Android 2.3:
A. Improvement & Repair User Interface
Changes to the menu and settings to make users more easily navigate and control the system features and devices and energy-efficient and faster performance.

2. Input text faster and Intuitive
virtual keyboard was redesigned and optimized for text input faster and easier editing.
3. The selection of words and text with a single touch and copy / paste
This version is much easier selection of words and text by touch and hold it without

4. Better energy management
With the enhanced version of this, energy management can be better in aturnya.
5. Manage Applications can be accessed from the Options menu
Manage Applications used to view any application running

6. Organizing features and better communication
This version supports communication via the Internet with SIP / VoIP, near-field communication (NFC reader) and a feature to select the front-rear camera.

Radim Vrbata scored twice and Mike Smith had 37 saves to shut out San Jose for the third time this season, leading the phoenix coyotes tickets  to a critical 2-0 victory over the Sharks on Thursday night.

Vrbata, who missed the previous two games because of a bad reaction to penicillin, had a power-play goal in the second period, then scored 8:17 into the third period on a slick pass from Ray Whitney. Whitney had two assists to reach 999 career points.

The Coyotes rose from ninth to seventh in the Western Conference, while San Jose fell from a tie for seventh to ninth behind idle los angeles kings tickets

Phoenix and Pacific Division leader Dallas both have 89 points, but the Stars have played one fewer game.

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A solar cooker, or solar oven, is a device which uses the energy of sunlight to heat food or drink to cook it or sterilize it. High-tech versions, for example electric ovens powered by solar cells, are possible, and have some advantages such as being able to work in diffuse light. However at present they are very unusual because they are expensive. The vast majority of the solar cookers presently in use are relatively cheap, low-tech devices. Because they use no fuel and cost nothing to operate, many nonprofit organizations are promoting their use worldwide to help reduce fuel costs for low-income people, reduce air pollution and slow deforestation and desertification, caused by use of firewood for cooking. Solar cooking is a form of outdoor cooking and is often used in situations where minimal fuel consumption is important, or the danger of accidental fires is high.

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In Ghana, Zouzugu villagers like this woman prevent dracunculiasis and other waterborne diseases by pasteurizing water in a CooKit solar cooker.

Low-tech solar cookers

There are various types of fairly simple solar cookers, which have been designed by using the following basic principles:

• Concentrating sunlight: A reflective mirror of polished glass, metal or metallised film is used to concentrate light and heat from the sun into a small cooking area, making the energy more concentrated and increasing its heating power.
• Converting light to heat: A black or low reflectivity surface on a food container or the inside of a solar cooker will improve the effectiveness of turning light into heat. Light absorption converts the sun’s visible light into heat, substantially improving the effectiveness of the cooker.
• Trapping heat: It is important to reduce convection by isolating the air inside the cooker from the air outside the cooker. A plastic bag or tightly sealed glass cover will trap the hot air inside. This makes it possible to reach similar temperatures on cold and windy days as on hot days.
• Greenhouse effect: Glass transmits visible light but blocks infrared thermal radiation from escaping. This amplifies the heat trapping effect.

Too many types of cookers exist ^[1] for all of them to be described here. The following selection outlines the most commonly used ones.

Sun Oven box cooker

 Box cookers

A box cooker has a transparent glass or plastic top, and it may have additional reflectors to concentrate sunlight into the box. The top can usually be removed to allow dark pots containing food to be placed inside. One or more reflectors of shiny metal or foil-lined material may be positioned to bounce extra light into the interior of the oven chamber. Cooking containers and the inside bottom of the cooker should be dark-colored or black. Inside walls should be reflective to reduce radiative heat loss and bounce the light towards the pots and the dark bottom, which is in contact with the pots. The box should have insulated sides. Thermal insulation for the solar box cooker must be able to withstand temperatures up to 150 °C (300 °F) without melting or out-gassing. Crumpled newspaper, wool, rags, dry grass, sheets of cardboard, etc. can be used to insulate the walls of the cooker. Metal pots and/or bottom trays can be darkened either with flat-black spray paint (one that is non-toxic when warmed), black tempera paint, or soot from a fire. The solar box cooker typically reaches a temperature of 150 °C (300 °F). This is not as hot as a standard oven, but still hot enough to cook food over a somewhat longer period of time. Food containing a lot of moisture cannot get much hotter than 100 °C (212 °F) in any case, so it is not always necessary to cook at the high temperatures indicated in standard cookbooks. Because the food does not reach too high a temperature, it can be safely left in the cooker all day without burning. It is best to start cooking before noon, though. Depending on the latitude and weather, food can be cooked either early or later in the day. The cooker can be used to warm food and drinks and can also be used to pasteurize water or milk.”A Simple Solar Water Pasteurizer”.wellmont theatre seating

 Panel cookers

HotPot panel solar cooker

Panel solar cookers are very inexpensive solar cookers that use reflective panels to direct sunlight to a cooking pot that is enclosed in a clear plastic bag. A common model is the CooKit. Developed in 1994 by Solar Cookers International, it is often produced locally by pasting a reflective material, such as aluminum foil, onto a cut and folded backing, usually corrugated cardboard. It is lightweight and folds for storage. When completely unfolded, it measures about three feet by four feet (1 m by 1.3 m). Using materials purchased in bulk, the typical cost is about US$5. However, CooKits can also be made entirely from reclaimed materials, including used cardboard boxes and foil from the inside of cigarette boxes.^[2]

The CooKit is considered a low-to-moderate temperature solar cooker, easily reaching temperatures high enough to pasteurize water or cook grains such as rice. On a sunny day, one CooKit can collect enough solar energy to cook rice, meat or vegetables to feed a family with up to three or four children. Larger families use two or more cookers.

Solar tea kettle in Tibet

The HotPot is an advanced panel cooker design that includes a glass bowl with an inner black steel liner and a glass top. The panel has polished aluminum sections that fold flat. The HotPot has high thermal gain due to exploiting the greenhouse effect. The HotPot is being used in various field projects around the world. ^[3]

Solar kettles

Solar kettles are solar thermal devices that can heat water to boiling point by relying on solar energy alone. Low-tech ones are used in the preparation of hot drinks, and to sterilize water. There are also fairly high-tech ones, using vacuum tube technology, which are described below under “High-tech solar cookers”.

Cookers with paraboloidal reflectors

Theory and background

Paraboloidal Solar Cooker. At high magnification, note segmented construction.

Parabolic curve showing focus (F), vertex (V), and rays of light being brought to the focus.

If a reflector is axially symmetrical and shaped so its cross-section is a parabola, it has the property of bringing light that has come from a very distant source such as the sun, so the rays of light are effectively parallel, to a point focus. The diagram shows parallel rays QP being reflected and then converging to the focus (or focal point), marked F. The point V, where the curvature of the parabola is greatest, is called its vertex. For the focussing to be accurate, the incoming rays have to be parallel to the axis of symmetry of the parabola, the line that passes through V and F. The distance between V and F is the focal length of the parabola. If the axis of symmetry is aimed at the sun, any object that is located at the focus receives highly concentrated sunlight, and therefore becomes very hot. This is the basis for the use of this kind of reflector for solar cooking.

Strictly, the three-dimensional shape of the reflector is called a paraboloid. A parabola is the two-dimensional figure. (The distinction is like that between a sphere and a circle.) However, in informal language, the word parabola and its associated adjective parabolic are often used in place of paraboloid and paraboloidal. In this article, the strictly correct words are used, but readers should be aware that they will probably find the informal usage in other places, including other articles in Wikipedia.

The dimensions of a symmetrical paraboloidal dish are related by the equation: 4FD = R², where F is the focal length, D is the depth of the dish (measured along the axis of symmetry from the vertex to the plane of the rim), and R is the radius of the rim. Of course, they must all be in the same units. If two of these three quantities are known, this equation can be used to calculate the third.

A more complex calculation is needed to find the distance measured along the surface of the dish from the vertex to the rim. This quantity is useful in determining the dimensions of the material that is needed to make the dish. An intermediate result Q is useful: Q = sqr[4F² + R²], where F and R are defined as above. The distance S from the vertex to the rim, measured along the surface of the dish, is then given by: S = RQ / (4F) + Fln[(R + Q) / (2F)]. (The abbreviation sqr indicates the square root of the quantity in square brackets after it. Likewise ln means the natural logarithm of the quantity in square brackets after it. “Scientific” pocket calculators have keys to perform both of these functions.)

Although paraboloidal solar cookers can cook as well as a conventional oven, they are difficult to construct. Paraboloids are compound curves, which are more difficult to make with simple equipment than single curves. Frequently, the reflectors are made approximately, using many small segments that are all single curves. They generate high temperatures and cook quickly, but require frequent adjustment and supervision for safe operation. Several hundred thousand exist, mainly in China. They are especially useful for large-scale institutional cooking.

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Focus-balanced reflectors

Paraboloidal reflectors that have their centres of mass coincident with their focal points are useful. They can be easily turned to follow the sun’s motions in the sky, rotating about any axis that passes through the focus. Two perpendicular axes can be used, intersecting at the focus, to allow the paraboloid to follow both the sun’s daily motion and its seasonal one. The cooking pot stays stationary at the focus. If the paraboloidal reflector is axially symmetrical and is made of material of uniform thickness, its centre of mass coincides with its focus if the depth of the reflector, measured along its axis of symmetry from the vertex to the plane of the rim, is 1.8478 times its focal length. The radius of the rim of the reflector is 2.7187 times the focal length. The angular radius of the rim, as seen from the focal point, is 72.68 degrees. ^[4]

Scheffler cooker. This reflector has an area of 16 m², and concentrates 3 kW of heat.

 Scheffler cookers

A Scheffler cooker (named after its inventor, Wolfgang Scheffler) uses a large ideally paraboloidal reflector which is rotated around an axis that is parallel with the earth’s by a mechanical mechanism, turning at 15 degrees per hour to compensate for the earth’s rotation. The axis passes through the reflector’s centre of mass, allowing the reflector to be turned easily. The cooking vessel is located at the focus which is on the axis of rotation, so the mirror concentrates sunlight onto it all day. The mirror has to be occasionally tilted about a perpendicular axis to compensate for the seasonal variation in the sun’s declination. This perpendicular axis does not pass through the cooking vessel. Therefore, if the reflector were a rigid paraboloid, its focus would not remain stationary at the cooking vessel as the reflector tilts. To keep the focus stationary, the reflector’s shape has to vary. It remains paraboloidal, but its focal length and other parameters change as it tilts. The Scheffler reflector is therefore flexible, and can be bent to adjust its shape. It is often made up of a large number of small plane sections, such as glass mirrors, joined together by flexible plastic. A framework that supports the reflector includes a mechanism that can be used to tilt it and also bend it appropriately. The mirror is never exactly paraboloidal, but it is always close enough for cooking purposes. Sometimes, the rotating reflector is located outdoors, and the reflected sunlight passes through an opening in a wall into an indoor kitchen, often a large communal one, where the cooking is done.^[5][6]

Cookers with parabolic trough reflectors

Single troughs

Parabolic troughs are used to concentrate sunlight for solar-energy purposes. Some solar cookers have been built that use them in the same way.[1] Generally, the trough is aligned with its focal line horizontal and east-west. The food to be cooked is arranged along this line. The trough is pointed so its axis of symmetry aims at the sun at noon. This requires the trough to be tilted up and down as the seasons progress. At the equinoxes, no movement of the trough is needed during the day to track the sun. At other times of year, there is a period of several hours around noon each day when no tracking is needed. Usually, the cooker is used only during this period, so no automatic sun tracking is incorporated into it. This simplicity makes this design attractive, compared with using a paraboloid. Also, being a single curve, the trough reflector is simpler to construct. However, it suffers from lower efficiency.

Using two parabolic troughs to simulate a paraboloid

It is possible to use two parabolic troughs, curved in perpendicular directions, to bring sunlight to a point focus as does a paraboloidal reflector.^[7] The incoming light strikes one of the troughs, which sends it toward a line focus. The second trough intercepts the converging light and focuses it to a point. A diagram of the principle can be seen here.

Compared with a single paraboloid, using two partial troughs has important advantages. Each trough is a single curve, which can be made simply by bending a flat sheet of metal. Also, the light that reaches the targeted cooking pot is directed approximately downward, which reduces the danger of damage to the eyes of anyone nearby. On the other hand, there are disadvantages. More mirror material is needed, increasing the cost, and the light is reflected by two surfaces instead of one, which inevitably increases the amount that is lost.

Experimental arrangements of this kind have been made, and have worked well. The two troughs have been held in a fixed orientation relative to each other by being both fixed to a wooden frame.[2] The whole assembly of frame and troughs has to be moved to track the sun as it moves in the sky.

The Solar Bowl in Auroville.

 Cookers with spherical reflectors

The Solar Bowl is a unique concentrating technology used by the Solar Kitchen in Auroville, India. Unlike nearly all concentrating technologies that use tracking reflector systems, the solar bowl uses a stationary spherical reflector. This reflector focuses light along a line perpendicular to the sphere’s surface and a computer control system moves the receiver to intersect this line. Steam is produced in the solar bowl’s receiver at temperatures reaching 150 °C and then used for process heat in the kitchen where 1,000 meals^[8] per day are served. ^[9]

[edit] Hybrid cookers

A hybrid solar oven is a solar box cooker equipped with a conventional electrical heating element for cloudy days or nighttime cooking. Hybrid solar ovens are therefore more independent. However, they lack the cost advantages of some other types of solar cookers, and so they have not caught on as much in third world countries where electricity or fuel sources simply do not exist.

A hybrid solar grill consists of an adjustable paraboloidal reflector suspended in a tripod with a movable grill surface.^[10] These outperform solar box cookers in temperature range and cooking times. When solar energy is not available, the design uses any conventional fuel as a heat source, including gas, electricity, or wood.

High-tech solar cookers

Although various ideas for high-tech solar cookers have been proposed, such as the electric oven powered by solar cells mentioned in the introduction, very few of them have progressed past the experimental stage to the point where they are used in practice. They are generally much more expensive than low-tech cookers, which precludes their use in third-world situations.

One exception consists of solar kettles that use vacuum tube technology. They use evacuated glass tubes to capture, accumulate and store solar energy needed to power the kettle. Besides heating liquids, since the stagnating temperature of solar vacuum glass tubes is a high 220 °C (425 °F), these solar kettles can also deliver dry heat and function as ovens and autoclaves. Moreover, since solar vacuum glass tubes work on accumulated rather than concentrated solar thermal energy, these solar kettles only need diffused sunlight to work and need no sun tracking at all. If solar kettles use solar vacuum tubes technologies, the vacuum insulating properties will keep previously heated water hot throughout the night e.g. the SK-TF, or the SunRocket Solar Kettle [3]

It is plausible that other high-tech solar cookers will become practical if and when the costs of components such as solar cells decrease.

Integrated Solar Cooking

It has been recognized that solar cookers are limited to cooking on clear days. Moreover, most people want to eat hot food late in the day, when the sun is low or has already set. For these reasons, solar cooking advocates are recognizing the need for combining three devices for a total cooking solution: a) some type of solar cooker; b) a fuel-efficient cookstove; c) an insulated storage container such as a basket filled with straw to store heated food. Hot food will continue to cook for hours if it is stored in a well-insulated container. With this three-part solution, fuel use is minimized while still providing hot meals reliably. This concept is referred to as “integrated solar cooking”^[11] or the “integrated cooking method”.^[12]

Using solar cookers

Solar oven in use

The different kinds of solar cookers have somewhat different methods for use, but most follow the same basic principles.

Food is prepared as it would be for an oven or stove top. Because food cooks faster when it is in smaller pieces, solar cookers usually cut the food into smaller pieces than they might otherwise.^[13] For example, potatoes are usually cut into bite-sized pieces rather than being roasted whole.^[14] For very simple cooking, such as melting butter or cheese, a lid may not be needed and the food may be placed on an uncovered tray or in a bowl. If several foods are to be cooked separately, then they are placed in different containers.

The container of food is placed inside the solar cooker, perhaps elevated on a brick, rocks, metal trivet, or other heat sink, and the solar cooker is placed in direct sunlight.^[13] If the solar cooker is entirely in direct sunlight, then the shadow of the solar cooker will not overlap with the shadow of any nearby object. Foods that cook quickly may be added to the solar cooker later. Rice for a mid-day meal might be started early in the morning, with vegetables, cheese, or meat added to the solar cooker in the middle of the morning. Depending on the size of the solar cooker and the number and quantity of cooked foods, a family may use one or more solar cookers.

The solar cooker is turned towards the sun and left until the food is cooked. Unlike cooking on a stove or over a fire, which may require more than an hour of constant supervision, food in a solar cooker is generally not stirred or turned over, both because it is unnecessary and because opening the solar cooker allows the trapped heat to escape and thereby slows the cooking process. If wanted, the solar cooker may be checked every one to two hours, to turn the cooker to face the sun more precisely and to ensure that shadows from nearby buildings or plants have not blocked the sunlight. If the food will be left untended for many hours during the day, then the solar cooker is often turned to face the point where the sun will be when it is higher in the sky, instead of towards its current position.^[15]

The cooking time depends primarily on the equipment being used, the amount of sunlight at the time, and the quantity of food that needs to be cooked. Air temperature, wind, and latitude also affect performance. Food cooks faster in the two hours before and after the local solar noon than it does in either the early morning or the late afternoon. Larger quantities of food, and food in larger pieces, take longer to cook. As a result, only general figures can be given for cooking time. With a small solar panel cooker, it might be possible to melt butter in 15 minutes, to bake cookies in 2 hours, and to cook rice for four people in 4 hours. However, depending on the local conditions and the solar cooker type, these projects could take half as long, or twice as long.

A low-cost thermometer has been invented to provide a reliable method for determining when the cooker has reached the temperature for pasteurization of water or milk (65 deg. C or 149 deg. F). This device is called the Water Pasteurization Indicator or WAPI.^[16]

It is difficult to burn food in a solar cooker.^[14] Food that has been cooked even an hour longer than necessary is usually indistinguishable from minimally cooked food. The exception to this rule is some green vegetables, which quickly change from a perfectly cooked bright green to olive drab, while still retaining the desirable texture.

For most foods, such as rice, the typical person would be unable to tell how it was cooked from looking at the final product. There are some differences, however: Bread and cakes brown on their tops instead of on bottom. Compared to cooking over a fire, the food does not have a smoky flavor.

Advantages

Solar cookers use no fuel, which means that their users do not need to fetch or pay for firewood, gas, electricity, or other fuels. Therefore, over time a solar cooker can pay for itself in reduced fuel costs. Since it reduces firewood use, the solar cooker reduces deforestation and habitat loss. Since there are about 2 billion people who are still cooking on open fires, widespread use of solar cookers could have large economic and environmental benefits. ^[17]

Solar box cookers attain temperatures of up to about 165 deg. C (325 deg. F), so they can be used to sterilize water or prepare most foods that can be made in a conventional oven or stove, from baked bread to steamed vegetables to roasted meat. When solar ovens are placed outside, they do not contribute unwanted heat inside houses.

Solar cookers do not produce any smoke as a product of combustion. The indoor concentration of health-damaging pollutants from a typical wood-fired cooking stove creates carbon monoxide and other noxious fumes at anywhere between seven and 500 times over the allowable limits.^[18] Fire-based cooking also produces ashes and soot, which make the home dirtier. However, any type of cooking, including solar cooking, can evaporate grease, oil, etc., from the food into the air.

Unlike cooking over an open fire, children cannot be burned by touching many types of solar cookers, which are made from cardboard or plastic and do not get hot. Unlike all fuel-based cooking arrangements, these solar cookers are not fire hazards. However, solar cookers that concentrate sunlight, e.g. with paraboloidal reflectors, do produce high temperatures which could cause injury or fire.

Disadvantages

Solar cookers are less usable in cloudy weather and at high latitudes, so some fuel-based backup heat source must still be available in these conditions. Also, solar cooking provides hot food during or shortly after the hottest part of the day, rather than the evening when most people like to eat. The “integrated solar cooking” concept accepts these limitations, and includes a fuel-efficient stove and an insulated heat storage container to provide a complete solution.

Many solar cookers take longer time to cook food than a fuel-based oven. Using these solar cookers therefore requires that food preparation be started several hours before the meal. However, it requires less hands-on time cooking, so this is often considered a reasonable trade-off.

Cooks may need to learn special cooking techniques to fry common foods, such as fried eggs or flatbreads like chapatis and tortillas. It may not be possible to safely or completely cook some thick foods, such as large roasts, loaves of bread, or pots of soup, particularly in small panel cookers; the cook may need to divide these into smaller portions before cooking.

Some solar cooker designs are affected by strong winds, which can slow the cooking process, cool the food, and disturb the reflector. In these cases it is necessary to anchor the reflector with string and weights.

 Solar cooking projects

Students perform an experiment, using a solar cooker built out of an umbrella.

Bakeries in Lesotho

Michael Hönes of Germany have established solar cooking in Lesotho, enabling small groups of women to build up community bakeries using solar ovens.^[19]

Darfur refugee camps

Cardboard, aluminum foil, and plastic bags for well over 10,000 solar cookers have been donated to the Iridimi refugee camp and Touloum refugee camps in Chad by the combined efforts of the Jewish World Watch, the Dutch foundation KoZon, and Solar Cookers International. The refugees construct the cookers themselves, using the donated supplies and locally purchased Arabic gum,^[20] and use them for midday and evening meals. The goal of this project was to reduce the Darfuri women’s need to leave the relative safety of the camp to gather firewood, which exposed them to a high risk of being beaten, raped, kidnapped, or murdered.^[21][22][23] It has also significantly reduced the amount of time women spend tending open fires each day, with the results that they are healthier and they have more time to grow vegetables for their families and make handicrafts for export.^[20] By 2007, the Jewish World Watch had trained 4,500 women, and had provided 10,000 solar cookers to refugees. The project has also reduced the number of foraging trips by as much as 70 percent, thus reducing the number of attacks.^[24]

Gaza

Some Gazans have started to make solar cookers in order to cook their meals, due to a lack of cooking fuels due to the Israeli blockade. The cooker is made from cement bricks, mud mixed with straw and two sheets of glass. About 40 to 45 Palestinian households reportedly have started using these solar cookers.

Indian solar cooker village

Bysanivaripalle, a silk-producing village that is 125 km (80 mi) northwest of Tirupati in the Indian state of in Andhra Pradesh, is the first of its kind: an entire village that uses only solar cooking. Intersol, an Austrian non-governmental organisation, sponsored the provision of powerful “Sk-14″ parabolic solar cookers in 2004

What is a Data Logger?
Technically speaking, a data logger is any device that can be used to store data. This includes many data acquisition devices such as plug-in boards or serial communication systems which use a computer as a real time data recording system. However, most instrument manufacturers consider a data logger a stand alone device that can read various types of electrical signals and store the data in internal memory for later download to a computer.
The advantage of data loggers is that they can operate independently of a computer, unlike many other types of data acquisition devices. Data loggers are available in various shapes and sizes. The range includes simple economical single channel fixed function loggers to more powerful programmable devices capable of handling hundreds of inputs.

Choosing a Data Logger
When choosing a data logger the following parameters should be considered.

• Input Signal
  OMEGA offers data loggers that are compatible with most types of signals. Some data loggers are dedicated to a certain input type while others are programmable for different types of inputs. OMEGA offers data loggers for the following types of signals.

  AC Voltage/Current	Light On/Off	Shock/Acceleration
  Bridge/Strain/Load/Pressure	Motor On/Off	Sound
  Dew point	PH Pressure	Temperature
  Event or State	Process Voltage/Current	Thermistor
  Frequency	Relative Humidity	Thermocouple
  Level	RTD

• Number of Inputs
  Data Loggers are available in both single and multi-channel designs. Some data loggers are capable of handling hundreds of inputs. OMEGA’s OMB-LOGBOOK-300 for example is expandable to over 400 channels.
• Size
  In many applications space is a limitation. In those cases the size of the data logger may be a critical selection parameter. OMEGA’s OM-CP family of data loggers are extremely compact and include models for most input types.
• Speed/Memory
  In comparison to real time data acquisition systems, data loggers generally have low sample rates. This is normally because they store data in internal memory which is limited. The higher the data rates the more memory required. Therefore when specifying a data logger it is important to determine the sample rate and the sample duration which can be used to calculate the required memory. For example. If an application requires sample rates of 1 per second and the test must last one hour, the data logger must be able to store 3600 samples(1 sample/sec x 1 hour x 3600 seconds/hour).
• Real Time Operation
  In some applications it may be desirable to display the data being collected in real time on a computer. Certain data loggers such as OMEGA’s OM-CP family support this feature.

Data Logger Frequently Asked Questions(FAQ)

Why Choose a Data Logger Over Other Types of Data Collection Instruments?
Three types of instruments are commonly used for collecting and storing data. They are 1)Real-Time Data Acquisition Systems, 2)Chart Recorders and 3)Data Loggers

Data loggers are normally more economical than chart recorders. They offer more flexibility and are available with a greater variety of input types. Most data loggers collect data which may be directly transferred to a computer. Although this option is available with some recorders, it normally adds significant expense to the recorder price.
Data acquisition systems offer a great deal of flexibility and are certainly attractive when high sample rates are required, however, since they require connection or installation into a computer, the computer must also be present and active when collecting the data. Data loggers can collect data independently of a computer. Data is normally collected in non-volatile memory for later download to a computer. The computer does not need to be present during the data collection process. This makes them ideally suited for applications requiring portability.

Do Data Loggers Need to be Connected to a Computer?
No, some data loggers provide an option for real-time display but all OMEGA data loggers collect data independently of the computer.

What is the Maximum Sample Rate for a Data Logger?
The sample rate depends on the specific model. Although most data loggers have a maximum data rate of 1 or 2 samples per second, OMEGA offers a number of data loggers that can sample in excess of 100 samples per second.

How are the Data Loggers Powered?
Most data loggers are battery powered some also offer an option for external power.

How Long Does the Battery Powered Logger Last?
The battery life of a data logger depends on a number of parameters including the specific model and sample rate. In general the faster the sample rate the shorter the battery life. Many OMEGA data loggers feature a battery life as long as ten years.

Will the Data Logger Loose its Data if the Power or Battery Fails ?
Most OMEGA data loggers use non-volatile memory for data storage. This means that the data will not be lost if the power fails.

How Long Can the Data Logger Record Data?
The recording duration is dependent on the memory capacity of the data logger and the desired sample rate. To determine the duration divide the memory capacity(number of samples the device can record) by the sample rate. As an example assume that a given data logger can store 10,000 samples. If it is desired to record 2 samples every minute, the data logger can run for 10,000/2 or 5,000 minutes(about 3.5 days). If the sample rate was cut in half(1 sample per minute), the recording period would double to 7 days.

Data Logger Types
	Miniature Single Input Data Loggers Miniature single input data loggers are generally low cost loggers dedicated to a specific input type. These types of data loggers are often used in the transportation industry. A typical application would be to include a temperature data logger in a shipment of food products to insure that the food temperature does not exceed acceptable limits. In addition to temperature miniature data loggers are available for a large variety of input types. most input types.
	Fixed Mount Multi-Channel Data Loggers Fixed input loggers have a fixed number of input channels which are generally dedicated for a specific type of input. OMEGA offers fixed input data loggers ranging from one to 8 channels.
	Handheld Multi-Channel Data Loggers Handheld multi-channel loggers are commonly used in applications where the data logger is to be carried from one location to another. They are also commonly used in benchtop or laboratory environments. In addition to storing data internally some models even contain on board printers which can produce an immediate hardcopy of the data.
	Modular Data Loggers A modular data logger is configurable and expandable through the use of plug-in modules. The modules are normally field configurable and the user has the option of adding as many channels to satisfy the application requirement.

Performance parameters of the boiler, like efficiency and evaporation ratio, decreases with time due to poor combustion, heat transfer surface fouling and poor operation and maintenance. Even for a new boiler, for reasons such as poor fuel quality and water quality can lead to poor performance of the boiler. Balance of heat can help in identifying heat loss that can or can not be avoided. Boiler efficiency tests can help in finding the deviation from the best efficiency boiler efficiency and target problem areas for corrective action.

a) The heat balance in the boiler combustion process can be described in terms of energy flow diagram. This diagram illustrates graphically how the incoming energy from the fuel is converted into useful energy flow and the flow of heat and energy loss. Thick arrow indicates the amount of energy contained in each stream.

Figure 10. Diagram of the heat balance of boiler energy

balance is the balance of the total energy entering the boiler to the boiler is left in a different form. The following figure provides a range of loss that occurred for pembangkitansteam.

Figure 11. Lost on the Fueled Boiler Coal

• Loss of energy can be divided into losses or can not be avoided. The purpose of Cleaner Production and / or energy assessment must reduce the loss that can be avoided, by improving energy efficiency. Following loss can be avoided or reduced:
• flue gas loss:-Excess air (reduced to the minimum value that depends on teknologiburner, surgery (control), and maintenance)-temperature flue gas (derived by optimizing maintenance (cleaning), load; better burner and boiler technology)
• loss due to unburnt fuel in the chimney and ash (optimize operation and maintenance; teknologiburner better) Lost dariblowdown
• (fresh feed water, condensate recycling)
• Loss of condensate (the largest possible amount of condensate)
• convection and radiation losses (reduced by better insulation of the boiler)

Thermal efficiency of boilers Boiler Efficiency is defined as the percent of energy (heat) input that is effectively padasteam generated. There are two methods of assessment of boiler efficiency:

• Direct methods:the energy gained from the working fluid (water dansteam) compared to the energy contained in a fuel boiler.
• Indirect Method: efficiency is the difference between loss and energy intake.

Boiler Blowdown

If the water is boiled and steam, dissolved solids contained in water will remain in the boiler. If there is a lot of solids in the feed water, the solid will terpekatkan and will eventually reach a level where their solubility in water will be exceeded and will precipitate from solution. Above a certain level of concentration, these solids led to the formation of foam and causing water entrainment kesteam. Sediment also resulted in the formation of crust on the inside of the boiler, Causes local heating becomes excessive and ultimately cause the failure of the boiler tube. It is therefore important to control the level of concentration of solids in suspension and dissolved in boiling water. This is achieved by a process called blowing down, certain volume of water is automatically removed and replaced with feed water. Thus the optimum level of total dissolved solids (TDS) in boiler water and discard solids that have been flat out from the solution and the surfaces of the boiler.Blowdown important to protect the heat exchanger surfaces of the boiler. However, blow down can be a source of heat loss is quite meaningful, if done incorrectly. Pengendalianblowdown good boiler can significantly reduce treatment costs and operational costs that

• lower pretreatment costs Consumption airmake up less
• Time to cessation of treatment to be reduced
• Increased boiler life
• Use of chemicals for water treatment to lower feed

Feed Water quality depends on proper water treatment to control kemurniansteam, deposits and corrosion. A boiler is part of the boiler system, which receives all the pollutants from the system in front of him. Boiler performance, efficiency and service life is a direct result of the election and control of feed water used in boilers. If the feed water into the boiler, the temperature rise and pressure cause the components of water have different properties. Almost all the components in the feed water in a dissolved state. However, under heat and pressure most of the components dissolved out of solution as solid particulates, sometimes in crystalline form and at other times as amorph. If the solubility of specific components in water is exceeded, there will be formation of crust and sediment. Boiler water should be quite free from the formation of solid deposits of heat transfer to occur quickly and efficiently and should not be corrosive to metal boiler. a) Control of sediment deposition in the boiler can result from the feed water hardness and corrosion of the condensate and feed water systems. Water may occur due to lack of system softening. Deposition and corrosion causing loss of efficiency that can cause failure in the boiler tube and the inability produce steam. Sediment acts as an insulator and slows heat transfer. A large number of deposits throughout the boiler can reduce the heat transfer can significantly decrease the efficiency of the boiler. Various types of deposits will affect the boiler efficiency differently, so it is important to analyze the characteristics of the sediment. The insulating effect of deposits causes the metal temperature to rise and may lead to boiler tube failures due to overheating

Understanding boiler According to UNEP (2006), A boiler is a closed vessel where the combustion heat flowed into the water until it forms a hot water or steam. Hot water or steam at a certain pressure and then used for transferring heat to a process. Water is a useful and inexpensive medium for transferring heat to a process. If water is boiled into steam, volumnya will increase by about 1,600 times, producing a force that gunpowder is explosive, so the boiler is a device that must be managed and maintained very well. Boiler system consists of: feed water systems, steam systems and fuel systems. Water system provides water to the boiler automatically as needed steam.Various valves are provided for purposes of maintenance and repairs. Steam system collects and controls the production of steam in the boiler. Steam is directed through a piping system to the user’s point. The entire system, steam pressure is set using the faucets and monitored with a pressure monitor. The fuel system is all the equipment used to provide fuel to generate the necessary heat. Equipment required on the fuel system depends on the type of fuel used on the system. Water supplied to the boiler to be converted into steam is called feed water. Two sources of feed water are:

(1) Condensate or condensed steam returned from the process and

(2) Makeup water (treated raw water) which must come from outside the boiler room and plant processes. To obtain a higher efficiency boiler, an economizer for heating feed water using waste heat in flue gases.

Types of Boilers boiler consists of various types, namely:

1. Fire T u some fire tube boilers in boiler,

hot gases pass through the pipe – pipe and boiler feed water in the shell is converted into steam. Fire tube boilers are generally used for steam capacity is relatively small with low to medium pressure steam. As a guideline, fire tube steam boilers are competitive for up to 12,000 kg / hr with pressures up to 18 kg / cm 2. Fire tube boilers can use fuel oil, gas or solid fuel in its operations. For economic reasons, most fire tube boiler is constructed as a “package” boilers (assembled by the manufacturer) for all fuels. Fire T u be Boiler

2. Water Q u some water tube boilers in boiler,

boiler feed water flowing through the pipe – the pipe into the drum.Tersikulasi water heated by gas burners in the form of steam vapor in the drum. This boiler is selected if its steam and the steam pressure is very high as in the case of boilers for power generation. Water tube boiler which is very modern designed with steam capacity of 4500-12000 kg / hr, with a very high pressure. Many water tube boiler that is constructed in a package if used fuel oil and gas. For water tube boilers using solid fuel, is not commonly designed package. Characteristics of water tube boiler as follows:

• Forced, induced and balanced draft helped to improve combustion efficiency

• Less tolerant of water quality resulting from water treatment plant

• Allows for the higher heat efficiency of Water Boiler T u be

The packaged boiler Boiler package because it was available as a complete package. At the time sent to the factory, requires only steam pipes, water pipes, fuel supply and electrical connections to operate. Package boilers are generally a shell and tube type with a fire tube design with good heat transfer of high radiation and convection.

The characteristics of packaged boilers are:

1. The small combustion chamber and the high heat released produces a more rapid evaporation.
2. A large number of small-diameter pipes that make it have a good convective heat transfer. System fo rc ed or induced draft combustion efficiency is good.
3. A number of trajectory / pass heat transfer produces better overall.
4. thermal efficiency levels higher than other denganboiler. These boilers are grouped by jumlahpass / tracks the number of times the combustion gases pass through the boiler. The combustion chamber is placed as the first pass after that one, two, or three sets of fire-tubes.

Boilers are most common in this class are units tigapass / track with two setfire-tube/pipa flames and the exhaust gases exiting from the back boiler.

Package Type Boiler

Pass, fuel oil Boiler Fluidized Bed Combustion (FBC) fluidized bed combustion (FBC) has emerged as a viable alternative and has significant advantages compared to conventional combustion systems and provides many advantages such as boiler design a compact, flexible fuel, higher combustion efficiency and reduced emissions of harmful pollutants such as SOx and NOx. Fuel can be burned in the boiler is coal, rejects washing clothes, rice husks, bagasse & other agricultural wastes. Fluidized bed boilers have a wide capacity range between 0.5 T / h to more than 100 T / hour. When air or gas is distributed evenly passed upward through a bed of solid particles such as sand supported on a fine mesh, the particles are undisturbed at low velocity. As air velocity

gradually rises, it becomes a state where particles suspended in air flow sehinggabed is called “fluidized”. With the increase in air velocity, there is bubble formation, strong turbulence, rapid mixing and formation of solid particles rapat.Bed permukaanbed which displays the properties of boiling liquid and looks like a fluid called “bubbling fluidized bed (bubbling fluidized bed)”. If sand particles in a fluidized state is heated to the temperature of a flame coal, and coal is injected continuously kebed, coal will burn rapidly danbed achieve a uniform temperature. Fluidized bed combustion (FBC) takes place at temperatures around 840 ° C to 950 ° C. Because the temperature is much below the ash fusion temperature, the melting of ash and problems related therein can be avoided. The lower combustion temperature is reached due to the high heat transfer coefficient due to rapid mixing in the fluidized bed and effective extraction of heat daribed through heat transfer tubes and walls of the bed. The gas velocity of minimum fluidization velocity and particle entrainment velocity. This ensures a stable operasibed and avoid particle entrainment in the gas.

Atmospheric Fluidized Bed Combustion (AFBC) Boiler Most boilers are in operation for this type adalahAtmospheric Fluidized Bed Combustion (AFBC) boilers. This tool is just a regular conventional shellboiler which coupled with a fluidized bed combustor. Such systems have been installed together with the water tube boiler / boiler of conventional water pipes. Coal is crushed into the size of 1-10 mm depending on the level and type of coal feed air into the combustion chamber. Atmospheric air which acts as fluidization and combustion air, is inserted by pressure, after preheated by exhaust gas fuel. Dalambed pipe that carries water generally act sebagaievaporator.The gaseous products of combustion pass through the super heater of the boiler and then flows keeconomizer, to the dust collector and air preheater before being discharged into the atmosphere.

Pressurized Fluidized Bed Combustion (PFBC) Boiler

In type Pressurized Fluidized Bed Combustion (PFBC), an air compressor supplying Draft (FD), and the combustor is pressurized tank. The rate of heat released dalambedcomparable to that in tekananbed sehinggabed used to extract large amounts of heat. Thiswill improve the combustion efficiency and sulfur dioxide absorption dalambed.Steamgenerated in the two tube bundles, one dibed and one above it. Move heat from the flue gasof gas turbine power generation. PFBC system can be used for cogeneration (steam and electricity) or a combined cycle power generation (combined cycle). Operating combined cycle (gas turbine & steam turbine) to increase overall conversion efficiency by 5 to 8 percent. 7.Atmospheric circulating Fluidized Bed Combustion Boilers (CFBC) In circulatorysystem, the bed parameters for solids elutriation daribed. Solids removed in a relatively dilute phase in the riser, and sebuahdown-comer with a cyclone for the solids. There are nopipelines located pembangkitsteam dalambed. Berlebihsteam generation and heatingtakes place in the convection, water walls, at the output of the lifter / riser. CFBC boilers aregenerally more economical than AFBC boilers, for application in the industry requires morethan 75-100 T / jamsteam. For large units, the higher the characteristics of CFBC boilerfurnace will provide a better use of space, a larger fuel particles, the residence timeabsorbing materials for efficient combustion and the capture of SO2 is the greater, and the easier the application of techniques for controlling NOx combustion pembangkitsteam thanAFBC.

Stoker Fired Boilers Stokers are classified according to the method of feeding fuel to thefurnace and by its jenisgrate. The main classifications are spreader stoker gateataudanchain-traveling-gate stoker. • Spreader Stokers Spreader Stokers utilizing a combination of suspension and pembakarangrate. Coal is fed continuously into the furnaceabove the bed combustion of coal. Soft coal is burned in suspension; larger particles will fallkegrat e, where the coal will be burned dalambed burning coal are thin and fast. Thiscombustion method gives good flexibility to load fluctuations, since ignition occurs almostinstantaneous when firing rate increases. Because of this, the spreader stoker is favored over other jenisstoker in many industrial applications.

Chain-traveling-grate stoker grateatau Coal is fed onto a moving steel e ujunggrat.Ketikagrat e moving along the furnace, the coal burns before dropping off at the end of theash. Required a certain skill level, especially when menyetelgrat e, the air damperdanbaffles, to ensure clean combustion and to produce a minimum amount of unburned carbon in the feed coal abu.Hopper extends along the entire end of the feed coal to the furnace. Sebuahgrat e coal is used to control the speed of the coal fed into the furnace by controlling the fuel ketebalanbed. The size of coal should be uniform because a large chunkwill not burn out completely at achieving ujunggrate.

Pulverized Fuel Boiler

Most of the power station boilers are fired using pulverized coal, and many industrial water-tube boilers that also use this fine coal. This technology is well developed and there are thousands of units worldwide and more than 90 percent capacity coal combustion is of this type. For the type of bituminous coal, coal ground to a fine powder, the size +300 micrometer (μm) of less than 2 percent and below 75 microns in size by 70-75 percent. It should be noted that the powder is too fine a waste of energy milling. In contrast, the powder is too coarse will not burn completely in the combustion chamber and cause greater losses due to unburnt. Powdered coal is blown with most air enters the combustion boiler plant through a series of noselburner. Secondary and tertiary air may also be added. Combustion takes place at temperatures from 1300 – 1700 ° C, depending on coal quality. Dalamboiler particle residence time is typically 2 to 5 seconds, and the particles must be small enough for complete combustion. This system has many advantages such as the ability to burn a variety of coal quality, quick response to changes in payload, the use of air temperature of the preheater
high etc.. One of the most popular system for burning pulverized coal is tangential firing using four buahburner from all four corners to create a fireball in the center of the furnace.

Figure Fuel combustion for smooth tangential

Waste Heat Boiler

Wherever the available waste heat at medium or high temperature, waste heat boiler can be installed economically. If kebutuhansteam more daristeam produced using the hot exhaust gases, can digunakanburner additional fuel use. Jikasteam not directly be used, steam can be used to produce electric power using steam turbine generators. It is widely used in heat recovery from flue gases from gas turbines and diesel engines.

Figure 8. Scheme Boiler Waste Heat

Thermic Fluid Heaters

Currently, thermic fluid heaters have been widely used in various applications for indirect heating processes. By using petroleum fluids as heat transfermedia, these heaters provide a constant temperature. Combustion system consists of a fixed grate with mechanical draft arrangements. Thermic fluid heaters modern oil-firedconsists of a double coil, tigapass construction and fitted with pressure jet system. Thermic fluid, which acts as a heat carrier, heated in the heater and circulated through theequipment user. Fluid is then heat through a heat exchanger to the process, then the fluid isreturned to the heater. Thermic fluid flow at the user end is controlled by a control valve ispneumatically operated, based on the operating temperature. Heaters operate at high fireor low depending on the return oil temperature which varies depending on system load. The advantage of these heaters are: Operation closed system with minimum losses as compared to steam boilers.
Operating system is not pressurized even for temperatures around 2500C compared to the needs tekanansteam 40 kg/cm2 in sistemsteam similar.   automatic control settings, which provide operational flexibility.   Thermal efficiency is good because there is no heat loss due to olehblowdown, disposal of condensate and flash steam. The overall economics of thermic fluid heaters depending upon the specific application and thereference basis. Thermic fluid heaters fired by the range of 55-65 percent thermal efficiency is most convenient to use than the most common boiler. Incorporation of heat recovery devices in the exhaust gas will further enhance the thermal efficiency

Interposing one between an adjustable-speed drive and its power source offers several benefits

FOR USERS OF ADJUSTABLE-speed (variable-frequency) motor drives, “inverter duty” implies one of two major problems. First is the damaging effect of output voltage spikes on the motor circuit itself, which has led to development of “inverter duty” insulation systems and special interconnecting cable. Second is the flow of harmonic currents in the power supply system, generating damaging harmonic voltages throughout that system.

Related to those well-known concerns are several others. An adjustable-speed drive, or ASD, may be not only the source of electrical circuit problems but their victim as well. Interposing a “drive isolation transformer” between the ASD and its power source offers several benefits.

Isolation means that no direct electrical connection exists between source and load. But that’s true for any transformer (other than an autotransformer). What makes the drive isolation transformer different is the placement of grounded electrostatic (Faraday) shielding between and around primary and secondary windings. That provides up to a million-fold decrease in the capacitive coupling involved in transferring common-mode voltage disturbance. Without such shielding, that capacitance allows passage through the transformer of high-frequency “noise” and transient voltage spikes.

Common-mode transients are those appearing between ground and neutral of the a-c system. (Although those two parts of the circuit are normally bonded together at one point, they cannot be presumed to be at the same potential throughout an entire power system.) Such disturbances arise from switchmode power supplies, drive operation, arc welders, lightning, or even from normal operation of such equipment as stepper motors. Some isolation transformers can also block “normal-mode” transients, appearing between line and neutral

In one instance, daily utility turn-on of a substation capacitor bank in an industrial park caused a transient voltage spike that was amplified by reflection from on-site capacitors in a nearby plant. That caused a number of small drives (typical rating 7.5 hp) to shut themselves off, resulting in costly process downtime. An isolation transformer can prevent such disruption.

Similarly, the isolation transformer acts to reduce transmission to the a-c source of line notching and other waveform anomalies generated within ASD equipment. Line notching can be particularly troublesome with d-c motor drives.

Another benefit consists in blocking induced ground currents. Converter/inverter circuits within an ASD produce capacitively coupled currents circulating through ground back to the source, which tend to disrupt digital communications and cause nuisance tripping of ground fault protective devices. An isolation transformer having a grounded-wye secondary confines such currents within the drive circuit. The effect is to create a “separately derived” power system having its own isolated ground (which is also a safety feature).

Since any transformer inherently introduces reactance into the circuit, it will inhibit transfer of harmonic currents between primary and secondary. The higher the harmonic frequency, the greater the reduction. The common delta-wye transformer connection alone will block transfer to the primary of triple harmonics (the third is most important), and some reduction in the fifth and seventh can also be expected.

Thus, the often-heard claim that an isolation transformer is essentially “transparent to harmonics” is an oversimplification. A tuned filter, designed to deal with specific harmonic orders, is a more effective harmonic barrier than any transformer (isolation or otherwise). However, the typical filter alone cannot deal with ground loops or “line noise.”

How large a transformer rating is needed? As Figure 1 shows, manufacturer guidelines differ widely. Cautions one supplier: “Select the drive isolation transformer according to the recommendations from the . . . drive system manufacturer. . . .”

Any transformer supplying an ASD must, of course, withstand the added heating caused by harmonic currents flowing in the windings (see “The mysterious transformer K-factors: What are they? What do they mean?” EA March 1992).

Also, the transformer must suit the drive overload capability. A pertinent standard after 1983 was IEEE 597, “Standard Practices and Requirements for General-Purpose Thyristor D-C Drives.” It called for drive capability of 150% of rated current for a one-minute period during each hour of operation. An upstream isolation transformer had to be able to support that overload cycle. However, although reaffirmed in 1991, IEEE 597 was later withdrawn. It exists today as nothing more than a historical reference. Otherwise, isolation transformers are subject only to the same general standards as any other dry-type units, such as UL 1561 and 1562 or IEEE C57.12.01.

By Richard. L. Nailen, P.E., EA Engineering Editor