How to Perform Statistical Computations Using Microsoft Excel: Analysis of Variance for Complete Random Design

Statistical computation is one of the hardest parts in the analysis of numerical data. Though there are specialized software programs designed to perform statistical computation and analysis, this operation can be done in Microsoft Excel, a program very common and familiar to us all.

 

The default Microsoft Excel does not immediately present the tools necessary for deeper statistical computation. However, these tools or add-ons are actually present in Excel but are not yet installed. To access and use them, you have to install them first. In my previous article (Statistical Computing Using Microsoft Excel: Basic Statistics), I have detailed the procedure on how to install the add-ons on Microsoft Excel. Please see link to follow the installation procedure.

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Solar Home Heating: Concepts and Methods

Solar home heating systems are gaining popularity nowadays despite its high initial investment. These systems basically utilize solar radiation to provide space heating. This means that power from electrical equipment for heating space is eliminated. There are two general systems of solar space heating based on how heat is captured. These are the passive and active solar heating system.

Passive solar heating. This system requires no equipment to capture solar radiation. Its concept is similar to heat building up inside your car when it is left parked under the sun. Heat naturally accumulates inside the space. In this design, windows, walls, and floors are made to collect, store, and distribute solar energy in the form of heat in the winter and reject solar heat in the summer. It does not use mechanical and electrical devices. Passive solar buildings aim to maintain interior thermal comfort throughout the sun’s daily and annual cycles while reducing the requirement for active heating system.

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Hydroponics: Concepts and Methods

Hydroponics is one of the many methods of soilless agriculture through which plants are grown using mineral nutrient solutions in water, without soil. Many commodity crops like tomatoes, onions, lettuce and cabbage have been successfully cultivated through hydroponics, and their produce well-accepted in many markets. The theory behind the method is that the soil is only a mineral nutrient reservoir and hence, it is not very essential to plant growth. The mineral nutrient can be introduced into a plant’s water supply artificially which is then readily absorbed by the plant’s root. The concept of hydroponics is significant in today’s world as it contributes to the growing concern for steadier food supply, as well as the reduction of suitable arable land for agriculture.

 

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Solar Lighting: Concepts and Methods

Households usually use fluorescent lamps, and even incandescent bulbs for some, as a source of lighting. These devices consume so much electrical energy which is sadly a great strain to the bills of household owners. However, lighting can be achieved naturally instead of using electrical lamps. We can utilize a free and abundant source – the sunlight. (image source)

Solar lighting is a method of harnessing the light from the sun to provide illumination to a space. Sunlight is collected and distributed throughout an area using specialized equipment or through the structural design itself. It implies wise selection of window types, sizes and orientation. The energy-saving idea is very useful in places receiving ample sunlight since no electricity is utilized to light up a space during the day. Individual features include clerestory windows, skylights and light tubes.

How to Perform Statistical Computations using Microsoft Excel: Basic Statistics

Statistics is all about data, particularly those quantitative information and even qualitative facts converted to numerical equivalents. So what is being done with these data? After collecting and organizing them, we summarize and present them in a simplified and compressed form that is easy to understand and discern. The much harder task is the interpretation of the results and of the summary you have made.

With regards to summarizing and presenting statistical data, the key activities are computation and creation of charts or tabular presentations. We can do it manually or using calculators. But with the bulk of data that you may have, such work would be difficult. However, Microsoft Excel can do the job with an eyes’ blink. It is a software program common to almost every computer and hence, this simple step-by-step tutorial can be followed by anyone.

In statistics, one way of summarizing data is to compute for the measures of central tendency (such as mean, median, and mode) and the measures of variation (such as standard deviation and variance). Here is a quick guide to computing them using Microsoft Excel.

                                                                                       

How to Organize Desktop Icons and Files: Using Fences

I have previously presented the basic way of organizing your files and desktop icons (see How to Organize Desktop Icons and Files: Creating Folders and Subfolders). Another way of doing this is using the software program Fences. This is a freeware and anyone can easily find this on Google search engine and then download it for free. As for me, I found this program at FileHippo which is one of my favorite sites in the Internet since I can easily download freeware and trial versions in this site (see Free Downloads at FileHippo).

Fences is a great program for those having problems with their desktop environment. It is an add-on to your desktop and its functionality is very indispensable. So what does Fences do? How can you organize your desktop using this program? What are its unique features?

How to Organize Desktop Icons and Files: Creating Main Folders and Subfolders

Documents placed everywhere. Irrelevant program icons found on the desktop. Most used programs not seen immediately. Files missing. Files here, there, and everywhere. Do you know what this means? An unorganized desktop environment.

We all commit this techie crime of just saving files, whether documents, pictures, or program icons, in our computer desktop. For obvious reason, we want to gain instant access to them. But over time, we find ourselves deleting some of them to accommodate newer files. If we do not wish to throw them into the Recycle bin, we simply drag or cut and paste them into different folders in our drives. And when we realize we want to see these files again, we find ourselves in deep trouble. We browse through countless folders with names very similar to one another, wishing to locate them so soon. We can use the Search option, but do we still remember the file name? Soon, we find ourselves screaming, OMG!

Marvelous Animal Robots II

Animals have certain unique abilities that humans cannot do. These abilities have been proven to be of valuable use to everyday human activities. Hence, human duplicates them by creating robots. Over the years, several robots have been designed and fabricated by engineers, scientists, and researchers. I have previously featured three amazing animal robots (see Marvelous Animal Robots). Here is the second list of three marvelous and awe-inspiring animal robots.

AirJelly

The AirJelly is the first indoor flight object with peristaltic drive. It is created by the German firm Festo. The robot is similar to the AquaJelly, another creation of the company. Unlike the AquaJelly, the AirJelly swims through the air, instead in the water. Its head and entire body is a huge ballonet filled with helium, making it float on air. The diameter of the ballonet is 1.35 meters, yielding a volume of 1.3 cubic meters of helium. For it to be lifted, the robot is at least 1.3 kilograms. (image source)

The AirJelly is equipped with a central electric drive unit and an intelligent, adaptive mechanism. It is moved by two lithium-ion polymer batteries connected to the central electric drive unit. From here, power is transmitted to a bevel gear which is connected to eight spur gears that move the eight tentacles of the jellyfish via cranks. The movement created in the tentacles, called as peristaltic motion, propels the ballonet forward. The movement or propulsion based on the principle of recoil is a new concept. This is what moves the AirJelly through the air.

SmartBird

One of the latest creations from Festo is the SmartBird. This is a great breakthrough in man’s efforts to decipher the flight of birds. The SmartBird is an ultralight but powerful flight model with excellent aerodynamic qualities and agility. It weighs only 450 g (15.87 oz) and has a wingspan of 1.96 m (6.4 ft). (image source)

 

Inspired by the herring gull, the SmartBird can start, fly and land autonomously. Its wings beat up and down, as well as twist at specific angles. The mechanism employed is an active articulated torsional drive unit combined with a complex control system. Its direction is controlled by the interaction of the electric motors found in its head and torso sections. Like that in true birds, the SmartBird’s tail produces lift and functions as both pitch elevator and yaw rudder. The battery, engine and transmission, crank transmission, and control and regulation electronics are also found inside the robot’s torso.

Genibo

Genibo is a robotic dog created by the Korean company of Dasarobot of Dasatech. It is similar in concept to Sony’s Aibo. It stands a foot tall and weighs 3.3 pounds. It is equipped with sensors, camera, and voice commands which enable it to identify itself and share “feeling” with its users.  It is capable of understanding over 100 voice commands such as “sit”, “roll over”, and “come here.” It can also change its mood according to user interaction, such as happiness, sadness, anger, and sleepiness. (image source)

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Solar Cooker: Types and Principles of Operation

With the continuous rise in the prices of basic commodities and the increasing threat posed by the use of fossil fuel, the need to harness free and renewable energy has gained much prominence. A very promising source of such energy is the sun which virtually cost nothing and pollution-free. One of the best technologies derived from the utilization of solar energy is the solar cooker.

A solar cooker, also known as solar oven, is a device that uses heat by concentrating or intensifying the heat from sunlight. Solar cookers are generally used for cooking, drying, and pasteurization, and are a form of outdoor cooking where sunlight is available. Many organizations are advocating on the use of such device, which is usually low-cost, because it helps slow down deforestation rate as gathering of firewood for cooking is avoided.

There are several types of solar cookers based on design. There are least 65 major designs and hundreds of variations of them. They differ on the mechanism of collecting and reflecting sunlight, but the principles of operation are similar. All these devices must be able to do perform three basic functions: to concentrate sunlight, to convert light to heat, and to trap heat. Reflective mirrors of polished glass, metal, or metalized film are used to concentrate sunlight to a small cooking area, thereby increasing the heat power. On the inside of the solar cooker, a black surface which is low in emissivity is provided to further improve the conversion of light to heat. Lastly, a sealed glass cover or related mechanism is used to trap hot air inside the solar cooker. With these factors considered, solar cookers can effectively work.

Some of the more common types of solar cookers are the following:

• Box Cooker

 

This is the simplest cooker which is first built in 1767 by Horace de Saussure. A basic box cooker consists of an insulated container with a transparent lid normally made of glass or plastic. The lid can be removed to allow dark pots containing food to be placed inside. The box cooker can work effectively with partially overcast skies and will typically reach temperatures of 90 – 150^OC. (image source)

• Panel Cooker 

The panel cooker uses a reflective panel to direct sunlight onto an insulated container, usually enclosed in a clear plastic bag. A very common model of this type of solar cooker is the CooKit developed in 1994 by Solar Cookers International. The CooKit is made of aluminum pasted on a corrugated cardboard which is cut and folded to shape. It is lightweight and when folded for storage only measures about three feet by four feet. In general, panel cookers can reach temperatures comparable to box cookers. (image source)

• Reflector Cooker

The reflector cooker uses various concentrating geometries (dish, trough, Fresnel mirrors) to focus light on a cooking container. These cookers reach temperatures of 315 °C and above but require direct light to function properly and must be repositioned to track the Sun.

           

a.      Solar Kettle

One example of a reflector cooker is the solar kettle. Solar kettles, used to heat water to boiling point, can generate temperatures as high as 220^OC. (image source)

b.      Parabolic Solar Cooker

This technology uses parabolic reflectors to concentrate sunlight. Its design is somewhat complex and difficult to fabricate. It also requires more precision to focus sunlight on the cooking vessel. Hence, the cooker must be frequently adjusted to catch sunlight and supervised for safe operation. Accordingly, it has the fastest cooking time for all cookers. (image source)

c.       Cookers with Spherical Reflectors

The Solar Bowl in Auroville, India is this type of technology. Its spherical reflector focuses light along a line perpendicular to the sphere’s surface and a computer control system moves the receiver to intersect this line. It can reach temperatures up to 150^OC. (image source)

• Hybrid Cooker

The hybrid cooker integrates conventional electrical heating elements in its layout for used during cloudy days or night time.

 

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Ten Major Disadvantages of Wind Energy

Wind is another good alternative for fossil fuel as a source of energy. There have been many technologies created to convert the force and power of wind into useful electrical or mechanical energy. Sometimes, wind power system is coupled with solar power in a hybrid system to have more efficient, reliable and steady source of energy. Though wind energy appears to be pollution-free and unlimited source of energy, it has many disadvantages that make it unappreciated by many. Here are some of the major disadvantages of wind energy.

Area. Wind turbines are large engineering structures. A single turbine may be inadequate to provide the power requirement of consumers, especially for large communities like an entire town, that construction of tens or hundreds of them would be necessary. Worse, wind turbines must be properly spaced from each other due to the turbulence they created, as well as to ensure that each receives sufficient wind. With the idea of putting up several farms, otherwise known as wind farm, and of correctly spacing them from each other would necessitate a great stretch of land.

Location.  The success of wind turbines lies on the abundance of wind. Hence, wind energy is site-specific or that not all areas are suitable for wind turbines that can supply enough electricity. Prevailing wind speed for a particular place must meet the requirements for the design of wind turbine. Accordingly, wind turbines tend to start up after 3-5 meters per second (6.7-11.2 mph), yet gives off less power output when speed goes above about 25 meters per second (56 mph). Moreover, wind turbines are best constructed on areas with high elevation and along coastlines where wind is relatively strong. Recently, some wind turbines have been put up right on the seas where breeze is much more favorable for power generation. Wind farms also need to be located reasonably near the area where the energy is used, to minimize loss in the energy transmission process.

Undependability factor. Wind turbines can only generate electricity when its blades or propellers are turned. In order to do this, there should be a steady stream of wind. But wind is not predictable and is not sufficiently available throughout the day. Its strength may vary from none to being violent. To compensate for this, the most appropriate design and construction must be considered which may consequently affect cost.

Uncontrollable. Unlike hydropower, wind energy is not a fixed resource. No one can control the wind supply and speed. It is intermittent and it just turns off and on anytime. Every other source of energy can be controlled, you can control your diesel and fuel generator, you can control your solar generator but it is impossible to control a wind generator. Hence, there should be other energy supplies if we want abundant electrical power. No matter how many turbines we construct, we cannot entire rely on wind turbines to provide the load. Even the wind turbine itself is uncontrollable. During heavy storms, propellers have great tendency to break off from the tower of the wind turbine. Moreover, wind energy cannot be also stored, especially on a large scale. Power plants are simply switched on if demands decrease, and they are eased off when demand drops.

Cost . The amount of construction and land acquisition involves large amounts of resources. Wind turbine and facilities cost a lost to fabricate. Since providing enough electricity requires large areas, costs will therefore escalate. Moreover, coastlines, a great location for wind turbines, are expensive personal properties, and not everyone can afford it, let alone a wind turbine.

Efficiency. According to Froude momentum theory, the maximum energy or power recoverable from wind is only 16/27 or 0.593 times its kinetic energy. Of this available energy, the amount that is actually utilized depends upon the aerodynamic efficiency of the blades, the friction losses in gearing, power transmission, wind velocity gradient due to ground effects, vibration dampening and other factors. In other words, efficiency of wind turbines can never exceed 59.30%.

Environmental Impact. There are reports that wind turbines kill birds, especially migratory birds. With the speed and length of propellers, which may extend to at least 100 feet, wind turbines potentially pose threats to birds. Others tell that the hum of the propellers is like an attraction to the birds since they like strong wind, and thus, they are lured into flying to them and eventually get killed. More recently, it is discovered that wind turbines can make bats’ lungs explode. Likewise, with the idea of constructing wind turbines on seas, marine life and ecosystem on surrounding waters will be destroyed and threatened during and after construction.  Lastly, others claim that wind turbines interfere radio and television signals.

Noise Pollution. Propellers when turned are very noisy. A wind generator makes a low, swooshing sound every hour each day. Many describe it as something similar to the hum of a small jet engine. Imagine many wind turbines creating such sound in a wind farm. That would be a lot of noise!

Aesthetics. Beauty is relative. Some may find a large expanse of land with wind turbines to be beautiful and picturesque, yet others might feel an eyesore or sees it as unsightly and boring. On small-scale, a relatively large wind turbine may not at all enhance the attractiveness of the yard.

Land Use Consideration. Like aesthetics, this is not a scientific or engineering problem but certainly a big issue. Construction of wind turbines will really change the “shape” of land. For some people, they feel the countryside should be left intact for everyone to enjoy its beauty, while for others, economic considerations despite the change in nature must be thought over.

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