Networking Concepts of Computer Networking

Networking Concepts of Computer Networking Posted on March 23, 2013 Networking is the practice of linking computing devices together with hardware and software that supports data communications across these devices. In computer networking, a server is a computer designed to process requests and deliver data to other computers over a local network or the Internet. Common types of network servers include Web, proxy and FTP servers. TCP/IP provides connection-oriented communication between network devices. TCP/IP is very commonly used both on the Internet and in home computer networks. Ethernet is a physical and data link layer technology for local area networks (LANs). Ethernet is reliable and inexpensive, the leading standard worldwide for building wired LANs. Network addresses give computers unique identities they can use to communicate with each other. Specifically, IP addresses and MAC addresses are used on most home and business networks. mplements information systems, software and networks. This professional will ensure that computer systems can operate efficiently and safely support the organization of information technology needs. COMPUTER NETWORKING Computer networks are everywhere today. They began during military service in 1950 and moved to American universities in 1960. Large firms became more dependent in 1970. This led to the birth of the Internet and the widespread use of computers throughout the major industries that consume up to the present day.

Abdullah ibn Masūd says

Abdullah ibn Masūd says, “A mountain calls out to another mountain by its name, ‘Oh so and so, has anyone passed you today remembering Allah ()?’ So, when the mountain replies, ‘yes’, it (the calling mountain) rejoices.”2 2. 1. Tabarani, al-Mujam-ul-kabir (9:103#8542) 2. Bayhaqi, Shuab-ul-iman (1:402#538) 3. Bayhaqi, Shuab-ul-iman (1:453#691) 4. Abu Nuaym, Hilyat-ul-awliya wa tabaqatul-asfiya (4:242) 5. Ibn Hayyan, al-Azmah (5:1717#11762) 6. Haythami, Majma-uz-zawaid (10:79) 7. Ibn Kathir, Tafsir -ul-Quran al-azim (3:140)

TAHIRA DAWN COACHIGN CENTER

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oDesk HTML 4.01 Test

Question:1 What is the character entity representation of the ‘less than’ sign (its entity name is ‘<’) ? a. 60;# b. < c. &60#; d. #60&; Question:2 You want to create a link for your website allowing users to email the webmaster. How will you implement this if the webmaster’s email is “webmaster@xcompany.com”? a. webmaster b. webmaster c. webmaster d. webmaster e. webmaster Question:3 You have to add a list of products in a drop-down list. What will you use to group the identical products under a category name? a. Optgroup b. option c. menu d. var Question:4 How will you specify a comment in an XHTML document? a. b. <– Here is a comment.. –> c. d. Question:5 Which of the following is true for the “” tag? a. It doesn’t need a closing tag b. The language attribute cannot be specified with it c. The name and type attributes are optional d. The class, id and title can be specified for it Question:6 How will you specify the language attribute in XHTML? a.

Listing A

b.

Listing A

c.

Listing A

d.

Listing A

Question:7 Which of the following is incorrect with regard to the tag? a. The “name” should be specified b. The “disabled” attribute disables the drop-down list c. The “multiple” attribute allows the user to choose multiple options d. The text specified in the “value” is displayed in the drop-down list e. None of the above Question:8 Which of the following lines will be allowed by an XHTML parser? a.

This is the starting of a new paragraph b.

This is the starting of a new paragraph

c. Here is a break statement

d. New Horizontal line

---

Question:9 You are developing a website. In one of the subscription forms, you need to get the subscription start date from the user. The HTML code is as follows: Day Month Year Which of the following will you use if you want to put these 3 text fields together in a box? a.

b. c.

d. Question:10 Which of the following is incorrect about the relation between HTML and XHTML? a. XHTML is a stricter and cleaner version of HTML * b. XHTML is almost identical to HTML 4.01 c. XHTML and HTML both are used to generate dynamic content d. XHTML brings together the elements of HTML and the syntax of XML Question:11 Which of the following is correct for an image? a. An image must be resized in an editor to fit in the specified space on a webpage b. If you have a big image but specify smaller height and width attributes in the tag, only the top left portion of the image will be displayed in the browser c. Both a and b are correct d. The height and width attributes allow resizing the image on the webpage Question:12 A defines the document type of any XHTML document. It can be of three types: a. Strict, Transitional, and Frameset b. Strict, Transitional and Loose c. Fixed, Intermediate and Loose d. Fixed, Intermediate, Frameset Question:13 Which of the following statements is correct with regard to DTDs? a. A strict DTD allows the user to use cascading style sheets b. A transitional DTD displays content in those browsers which don’t support CSS c. A frameset DTD is used to partition the browser window d. All of the above Question:14 Which of these tags will create a single space character? a. b. c.   d. Question:15 Which of the following statements is correct for the

tag? a. The text under blockquote must be enclosed in a block level element in a strict DTD document b. The attribute named “cite” must be specified c. Closing the tag is optional d. It doesn’t place an empty line after the text Question:16 A developer wrote this image tag: What code should follow this? a. b. c. d. Question:17 Which attributes of the tag is deprecated in HTML 4.01 and not supported in strict DTD XHTML? a. Align b. bgcolor c. cellspacing Question:18 Which of the following represents the basic tag structure of an XHTML document? a. b. c. d. Question:19 Please choose the most appropriate option. One of the differences between XHTML and HTML 4.01 is that the “name” attribute has been replaced by the “id” attribute in: a. img and applet tags b. img and map tags c. map and frame tags d. img, map, frame and applet tags e. frame, applet, style and map tags Question:20 You have defined the following image in an XHTML document: a. The code will only work properly in a browser that supports XHTML b. The code will work properly in a browser that supports both HTML 4.x and XHTML c. The code will only work properly in a browser that supports HTML 4.x d. The code is incorrect, it will not work in any browser Question:21 What do you understand by cellspacing? a. It makes the cell span more than one column b. It specifies the space between the cell wall and the contents of the cell c. It specifies the space between two cells d. It makes the cell span more than one row Question:22 Which of the following statements is true about the table header, body and footer tags? a. The table header, body and footer tags are , and respectively b. The table header, body and footer tags are , and respectively c. It is recommended to first specify the table header followed by the footer and then the body tag d. None of the above Question:23 Which attribute specifies the submit URL in a form? a. method b. Action c. name d. id Question:24 Which of the following is not correct for a tag? a. It is more useful if it is placed in a head element b. It can be used to specify the keywords for the search engines c. It can be used to redirect users to other URLs d. It is mandatory to specify the name or scheme attributes Question:25 What do you understand by the following line of code? a. xmlns specifies the URL to qualify the names used in the XHTML document b. xmlns means html-xml number sequence c. Elimination of xmlns tag will result in the document not being validated by a w3.org validator d. The page will not be displayed properly if the URL is changed to “http://www.w3.org/1999/xhtml” Question:26 The following registration form was coded by a programmer in XHTML: 1. 2. Name: 3. 4. Registration Date: 5. 6. Account Type: 7. 8. Primary 9. Secondary 10. Which of the following options is true with regard to this XHTML document? a. The syntax of the input tag at line 3 is incorrect b. The readonly attribute in line 5 is not correctly coded c. The syntax of the select tag is not correct d. Maxlength cannot be specified with text boxes Question:27 Take a look at the following code:

Defining HTML What will happen when you run this code in the browser? a. With a .html extension, the page will be displayed with errors b. With a .html extension, the page will not be displayed at all c. With a .xhtml extension, the page will be displayed with errors d. With a .xhtml extension, the page will not be displayed at all Question:28 On one of your web pages named “Listing.xhtml” you specified a target like this: Old Listing How will you make a link to the above target? a. Check Old Listing as well b. Check Old Listing as well c. Check Old Listing as well d. Check Old Listing as well Question:29 You placed four radio buttons on a web form. You want the users to specify whether they are male or female and whether they are married or single. The code is as follows: Male: Female: Married: Single: What is wrong with the above code? a. It will allow the user to choose only the male and the married options b. It will allow the user to choose only the female and single options c. It will allow the user to choose only one option out of the four d. It will allow the user to choose all the four options at the same time Question:30 You specified a base tag and anchors as follows: 1. 2. Yahoo 3. Google Which of the following is true for the above code? a. Only the Yahoo link will open in a new window b. Only the Google link will open in a new window c. Both links will open in a new window d. Both links will open in the same window Question:31 Which of the following is correct regarding the frame attribute of the table tag? a. It is used to add a frame to the table * b. A “hsides” frame attribute will show the border lines for horizontal sides of the table only c. A “hsides” frame attribute will not show the border lines for horizontal sides of the table only d. A “hsides” frame attribute will add a scrollable frame on the horizontal sides of the table Question:32 Which of the following is correct about the tag? a. It is not considered to be mandatory as per the XHTML specification b. It must have a closing tag c. It should come just after the tag d. Its declaration is not a part of the XHTML document itself e. None of the above Question:33 What do you understand by cellpadding? a. It makes the cell span more than one column b. It specifies the space between the cell wall and the contents of the cell c. It specifies the space between two cells d. It makes the cell span more than one row Question:34 Your website has moved to some other address. How will you automatically redirect a user to that address within 3 seconds of landing on the old address? a. b. c. d. Question:35 You want to provide a form field to the users for writing lengthy comments on the quality of the services provided by you. Which of the following tags will you use? a. Your comments …. b. Your comments …. c. Your comments …. d. Question:36 Your browser supports bidirectional text. Which tag will you use if you need to display text from right to left? a. Text should go in opposite direction b.

Text should go in opposite direction

c. Text should go in opposite direction d. Text should go in opposite direction

SPIRITUALISM AND MAGNETISM

In the Name of Allah, the Beneficent, the Merciful Mawla ya salli wa sallim da’iman abadan ‘Ala habibika khayr-il-khalqi kullihimi O Lord, send continuous and everlasting salat and blessings on Your Beloved who is the best of all creatures. In the quest of knowledge, the modern man has also discovered that the centuries old concepts about religion are contrary to the scientific thought and, therefore, need to be either discarded or made compatible with the scientific method. This is the challenge that the religious scholars and theologians have failed to face. Instead of analyzing the problem on scientific basis, they have adhered to their timeworn ideologies with a practical surrender to the materialistic values in vogue. Even the torchbearers, the socalled intellectuals and modern scholars of Islam who pretend to be abreast with the modern scientific thought have given in to the onslaught of modern sciences and in secret depths of their hearts feel nervous how to defend their position. They are doing more harms than good by defending their post with archaic weapons. regards eman

Thursday, November 8, 2012

power, electric: Sources of Electrical Energy — Infoplease.com

power, electric

Sources of Electrical Energy

Electrical energy occurs naturally, but seldom in forms that can be used. For example, although the energy dissipated as lightning exceeds the world's demand for electricity by a large factor, lightning has not been put to practical use because of its unpredictability and other problems. Generally, practical electric-power-generating systems convert the mechanical energy of moving parts into electrical energy (see generator). While systems that operate without a mechanical step do exist, they are at present either excessively inefficient or expensive because of a dependence on elaborate technology. While some electric plants derive mechanical energy from moving water (hydroelectric power), the vast majority derive it from heat engines in which the working substance is steam. Roughly 89% of power in the United States is generated this way. The steam is generated with heat from combustion of fossil fuels or from nuclear fission (see nuclear energy; nuclear reactor).

Steam as an Energy Source The conversion of mechanical energy to electrical energy can be accomplished with an efficiency of about 80%. In a hydroelectric plant, the losses occur in the turbines, bearings, penstocks, and generators. The basic limitations of thermodynamics fix the maximum efficiency obtainable in converting heat to electrical energy. The necessity of limiting the temperature to safe levels also helps to keep the efficiency down to about 41% for a fossil-fuel plant. Most nuclear plants use low-pressure, low-temperature steam operation, and have an even lower efficiency of about 30%. Nuclear plants have been able to achieve efficiency up to 40% with liquid-metal cooling. It is thought that by using magnetohydrodynamic"topping" generators in conjunction with normal steam turbines, the efficiency of conventional plants can be raised to close to 50%. These devices remove the restrictions imposed by the blade structure of turbines by using the steam or gasses produced by combustion as the working fluid.
Environmental Concerns The heat generated by an electric-power plant that is not ultimately converted into electrical energy is called waste heat. The environmental impact of this waste is potentially catastrophic, especially when, as is often the case, the heat is absorbed by streams or other bodies of water. Cooling towers help to dispose waste heat into the atmosphere. Associated with nuclear plants, in addition to the problem of waste heat, are difficulties attending the disposal and confinement of reaction products that remain dangerously radioactive for many thousands of years and the adjustment of such plants to variable demands for power. Public concern about such issues—fueled in part by the accidents at the Three Mile Island nuclear plant in Harrisburg Pennsylvania in 1979, and the nuclear plant explosion in the Soviet Union at Chernobyl in 1986—forced the U.S. government to introduce extensive safety regulations for nuclear plants. Partly because of those regulations, nuclear plants are proving to be uneconomical. Several are being shut down and replaced by conventionally fueled plants.
Alternative Energy Sources Fuel cells develop electricity by direct conversion of hydrogen, hydrocarbons, alcohol, or other fuels, with an efficiency of 50% to 60%. Although they have been used to produce electric power in space vehicles and some terrestrial locations, several problems have kept them from being widely used. Most important, the catalyst, which is an important component of a fuel cell, especially one that is operating at around room temperature, is very expensive. Controlled nuclear fusion could provide a virtually unlimited source of heat energy to produce steam in generating plants; however, many problems surround its development, and no appreciable contribution is expected from this source in the near future.
Solar energy has been recognized as a feasible alternative. It has been suggested that efficient collection of the solar energy incident on 14% of the western desert areas of the United States would provide enough electricity to satisfy current demands. Two main solar processes could be used. Photovoltaic cells (see solar cell) convert sunlight directly into electrical energy. Another method would use special coatings that absorb sunlight readily and emit infrared radiation slowly, making it possible to heat fluids to 1,000°F (540°C) by solar radiation. The heat in turn can be converted to electricity. Some of this heat would be stored to allow operation at night and during periods of heavy cloud cover. The projected efficiency of such a plant would be about 30%, but this fairly low efficiency must be balanced against the facts that energy from the sun costs nothing and that the waste heat from such a plant places virtually no additional burden on the environment. The principal problem with this and other exotic systems for generating electricity is that the time needed for their implementation may be considerable.
Windmills, once widely used for pumping water, have become viable for electric-power generation because of advances in their design and the development of increasingly efficient generators. Windmill "farms," at which rows of windmills are joined together as the source of electrical energy, serve as a significant, though minor, source of electrical energy in coastal and plains areas. However, the vagaries of the wind make this a difficult solution to implement on a large scale.
See also energy, sources of.

Sections in this article:

• Introduction
• Sources of Electrical Energy
• Transmission of Electrical Energy
• Reactive Power
• Bibliography

Friday, November 2, 2012

useful health tips

HEADACHE? - EAT FISH!: Eat plenty of fish - fish oil helps prevent headaches. So does ginger, which reduces inflammation and pain. HAY FEVER? EAT YOGURT!: Eat lots of yogurt before pollen season. Also-eat honey from your area local region) daily. TO PREVENT STROKE - DRINK TEA!: Prevent build-up of fatty deposits on artery walls with regular doses of tea. INSOMNIA (CAN'T SLEEP?) - HONEY!: Use honey as a tranquilizer and sedative. ASTHMA? - EAT ONIONS!: Eating onions helps ease constriction of bronchial tubes. ARTHRITIS? - EAT FISH, TOO!: Salmon, tuna, mackerel and sardines actually prevent arthritis. UPSET STOMACH? - BANANAS - GINGER!: Bananas will settle an upset stomach. Ginger will cure morning sickness and nausea. BLADDER INFECTION? DRINK CRANBERRY JUICE!: High-acid cranberry juice controls harmful bacteria. BONE PROBLEMS? EAT PINEAPPLE!!!: Bone fractures and osteoporosis can be prevented by the manganese in pineapple. PRE-MENSTRUAL SYNDROME? EAT CORNFLAKES!: Women can ward off the effects of PMS with Cornflakes, which help reduce depression, anxiety and fatigue. MEMORY PROBLEMS? EAT OYSTERS!: Oysters help improve your mental functioning by supplying much-needed zinc. COLDS? EAT GARLIC!: Clear up that stuffy head with garlic. COUGHING? USE RED PEPPERS!!: A substance similar to that found in the cough syrups is found in hot red pepper. Use red (cayenne) pepper with caution-it can irritate your tummy. BREAST CANCER?: Wheat, bran and cabbage help maintain estrogen at healthy levels. LUNG CANCER? EAT DARK GREEN AND ORANGE AND VEGGIES!: A good antidote is beta-carotene, a form of Vitamin A found in dark green and orange vegetables. ULCERS? EAT CABBAGE ALSO!!!: Cabbage contains chemicals that help heal both gastric and duodena ulcers. DIARRHEA? EAT APPLES!: Grate an apple with its skin, let it turn brown and eat it to cure this condition. CLOGGED ARTERIES? EAT AVOCADO!: Mono unsaturated fat in avocados lowers cholesterol. HIGH BLOOD PRESSURE? EAT CELERY AND OLIVE OIL!: Olive oil has been shown to lower blood pressure. Celery contains a chemical that lowers pressure too. BLOOD SUGAR IMBALANCE? EAT BROCCOLI AND PEANUTS!: The chromium in broccoli and peanuts helps regulate insulin and blood sugar. KIWI: Tiny but mighty. This is a good source of potassium, magnesium, Vitamin E & fibre. It's Vitamin C content is twice that of an orange. APPLE: An apple a day keeps the doctor away? Although an apple has a low Vitamin C content, it has antioxidants & flavonoids which enhances the activity of Vitamin C thereby helping to lower the risks of colon cancer, heart attack & stroke. STRAWBERRY: Protective fruit. Strawberries have the highest total antioxidant power among major fruits & protect the body from cancer causing, blood vessels clogging free radicals. ORANGE: Sweetest medicine. Taking 2 - 4 oranges a day may help keep colds away, lower cholesterol, prevent & dissolve kidney stones as well as lessen the risk of colon cancer. WATER MELON:Coolest Thirst Quencher. Composed of 92% water, it is also packed with a giant dose of glutathione, which helps boost, our immune system. They are also a key source of lycopene - the cancer fighting oxidant. Other nutrients found in watermelon are Vitamin C & Potassium. GUAVA & PAPAYA: Top awards for Vitamin C, they are the clear winners for their high Vitamin C content. Guava is also rich in fibre, which helps prevent constipation. Papaya is rich in carotene, this is good for your eyes. Tips on how to stay young....... 01. Laugh & have fun, don't be gloomy. 02. Let bygones be bygones. Dwelling on the past inflicts unnecessary stress. 03. Early to bed, early to rise, is healthy & wise. 04. Stay lean, being just 30% overweight is bad. 05. Keep learning, reading & socializing - an alert & active mind keeps brain cells healthy. 06. Keep working, doing something you like. Don't retire. It slows down your body. 07. Be the boss of your own life. Letting others push you around produces stress. 08. Too many pills ruin your body. Take just what you need. 09. Constantly alternating between weight gain & loss is bad. 10. Exercise, quit smoking & eat less fatty foods. 11. Do not worry about health or death, just get on with your life & enjoy it!

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