9/17/09

CPU Cooling methods

CPU cooling methods

The massive activity that goes on inside your PC generates extensive heat., sometimes known to reach 185 degrees F. The reasons for your PC heating up are
• Insulation caused by dust – dust filters can be provided and other persistent dust can be vacuumed out
• Scant or erratic airflow – can be modulated for even spread

Optimally the CPU has to be maintained around a temperature of 70 degrees F. A CPU coolant does just that. In its absence, overheat leads into myriad problems culminating in frequent crash-downs, computer freezing and in curtailing the life-span of the computer.
A passive heat sink is the basic type of CPU cooler. It draws heat away from the processor, which is dissipated over a large metallic (aluminum is commonly used) surface area. When a fan, atop the sink, or below it, exchanges the heat from the chip, for cooler air, this becomes an active heat sink When suitable computer parts are throttled to bring down the heat it is called soft cooling.
The sink is attached to the processor using spring or screw devices or a thermal interface material that adheres the processor to the heat sink. The interface material should be used in computers, for which mounting the sink on screws or springs is not possible. An inappropriate application of thermal compound can lead to inadequate heat transfer.


A good heat sink characteristics

Fans (about 12 volts power and 2X120 mm dimension) have to be designed optimally to dissipate the right amount of heat
• The right surface area for heat transfer
• Designed for maximum thermal transfer – a factor dependent on the material of the sink and the thickness of the fins (Thick fins – good conductivity, fine fins – better dissipation)
• A combination of optimal area and the fins spaced at the right distance should be sought
• Flat surface at the heat source ensures an even, thin application of interface material, for better cooling
• At the surface of contact the level of adherence must be high, to provide good pressure

The performance of the sink is measured in C/W or K/W (thermal resistance), not in the regular temperature scales like Centigrade or Kelvin, as difference in temperature is the required parameter

For instance of a load of 30W is applied and the temperature rises by 15 degrees C then the performance is rated as
15C/30 W = ½ C/W.
However you cannot use this parameter as one of the criteria for purchase of your computer, because the thermal resistance displayed on the product may be inaccurate or exaggerated, as a marketing strategy.

Liquid cooling
This consists of a combination of
• a system of pipes with liquid, that run inside the cooling system to extract heat from the processor and cool it
• a pump for liquid circulation. a cooling block to wring out the heat from the microprocessor
• a optional radiator with a condenser coil to decrease the temperature of water and send out the hear from the CPU onto the cooling arrangement
PCs with this set up do not need fans whereas a Cray 2 will need radiators to complete the set up.
The liquid must
exhibit a lower level of thermal conductivity
• have a certain extent of dielectric nature
Generally the liquids used are motor oils, various other oils including cooking oil, and Flour inert, (a special cooling oil manufactured by the 3M Company)

Water is used significantly in computers set for overclocking. Liquid nitrogen (or sometimes dry ice) cooling can generate a high efficiency rate in computer working. This uses water as the medium to cool/condense… However nitrogen is used only in highly overclocked situations as it needs to be refilled. Besides, the system may succumb to the temperature deviations created, created within the cooling system.

Be wary of
Heated liquid- This problem is taken care of by fans, usually low-noise ones, to cool the liquid which are set up outside the portable computer’s case.
• Evaporation –When the overheated liquid eventually evaporates, resort to sealing the medium within the computer or refill the liquid whenever needed
• Seepage- For leak problems, disconnect the computer from the power source, mop the seepage with an absorbing cleaning material , identify the source of leakage and replace it… Avoid skin contact with coolant, as it may cause irritation.

The other cooling options and methods are
Peltier cooling creates a temperature difference using Bismuth-telleride thermocouples, stacked in hundreds on the principle of Seebeck effect
• HVAC systems in large Data Centers
• Phase Change cooling in PCs, situated under it with pipes reaching the processors
• H2Ceramic Cooling –uses sensors to detect overheat-combining with Peltier and liquid cooling

Heat Sensors To help manage CPU cooling the motherboard can be equipped with a smart sensor to indicate voltage, temperature of the CPU and the fans. Smart sensors are now being equipped with features that can, on excess heating
• set off an audio alarm
• flash a warning message on your screen
• shut down the system automatically.


For more related information you can reach to
http://www.heatsink-guide.com/
http://en.wikipedia.org/wiki/CPU_cooling#Spot_Cooling
http://www.pantherproducts.co.uk/Articles/CPU/CPU%20Cooling.shtml
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A+ Test
1. Should the fans
a)blow air towards the heat sink
b)draws air away from it
c)change to and fro in direction
to cool effectively

2. The fins on the should be
a) Fine and closely spaced
b) Thicker and closely spaced
c) Fine and widely spaced
d) Thick and widely spaced
3. Cooking oil is a good option as a cooling liquid because
a) It is an electrical Insulator
b) It can dispel heat
c) Both the above
d) Neither of the above because It has a very low melting point
4. Cables for airflow in a cooling unit must be
a) Flat ribbon cables to synchronize with the storage drive and holding the conductive wires together tightly, to reduce surface area
b) Rounded cables holding the conductive wires together tightly to reduce surface area
c) Neither of the above
5. Consider these statements regarding water as the cooling liquid for your CPU
A. Freezing point of water used in coolants can be reduced with additives.
B. Color is added to monitor flow
C. Anti corrosive/antimicrobial additives increases its efficiencyas a cooling medium
a) A,B and C are essential
b) A is optional
c) B is Optional
d) C is optional
e) All additives are optional . water works fine without any of them

9/12/09

NUMBER PATTERNS AND SEQUENCES TUTORIAL

NUMBER PATTERNS AND SEQUENCES TUTORIAL

Subject : Mathematics Form 1




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Learning Objective : Number Patterns and Number Sequences Learning Outcomes : 1. Identify patterns of number sequences. 2. Extend, complete and construct number sequences. 3. Recognize odd and even numbers and explore their general properties. 4. Identify prime numbers. 5. Understand factors and prime factors. 6. Find the common factors and highest common factors (HCF). 7. Understand multiples. 8. Find the common multiples and lowest common multiples (LCM

2.1 Number Patterns & Number Sequences - A list of numbers that follow a certain pattern is called number sequence. - In a number sequence, we can see how the number pattern is form.


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1. 3, 7, 11, 15, 19 Pattern : begin with 3 and add 4 to the number before it (+4) 2. 305, 300, 295, 290, 285 Pattern : begin with 305 then minus / subtract 5 from the number before it (- 5) 3. 2, 6, 18, 54, 162 Pattern : begin with 2, then multiply each number by 3 (x3) 4. 64, 32, 16, 8, 4 Pattern : begin with 64 then divide each number by 2 (÷ 2)


Complete the missing number in the n
List the number sequences for these number sequences 1. 3, 6, 9 , 12, 15 , 18 Pattern : + 3 2. 64, 56, 48, 40, 32, 29 Pattern : - 8 3. 7, 21, 63, 189, 567, 1761 Pattern : x 3 4. 800, 400, 200, 100, 50, 25 Pattern : ÷ 2

umber patterns
1. List down the whole numbers between 30 to 37 31, 32, 33, 34, 35, 36 2. Add 5 to whole numbers from 3 to 28 3, 8, 13, 18, 23, 28 3. Subtract 3 from whole number from 13 to 1 13, 10, 7, 4, 1 4. Multiply 4 to whole numbers from 2 to 128 2, 8, 32, 128


2.2 Even Numbers & Odd Numbers
- Even numbers are whole numbers that can be divided by 2 exactly (no remainder). Example: 2, 4, 6, 8, 10, … - Odd numbers are whole numbers that cannot be divided by 2 exactly (has remainder). Example: 1, 3, 5, 7, 9, 11, … - ‘0’ is neither an add number nor an even number Determine whether these numbers are even numbers or odd numbers 1. 214 214 ÷ 2 = 107 therefore 214 is an even number 2. 735 735 ÷ 2 = 367 remainder 1 therefore 735 is an odd number 3. 2 579 2 579 ÷ 2 = 1 289 remainder 1 therefore 2 579 is an odd number 4. 5 550 5 550 ÷ 2 = 2 775



2.3 Prime Numbers
- Prime number is a whole number that can only be divided by itself and number 1 - The number 1 is not a prime number because it can only be divided by itself - All the prime numbers are odd numbers except for 2 - Example : 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, … Determine whether this number is a prime number or not 1. 31 31 ÷ 1 = 31 31÷ 31 = 1 31 can only be divided by 1 and itself. 31 is a prime number 2. 65 65 ÷ 1 = 65 65 ÷ 65 = 1 65 ÷ 5 = 13 65 can be divided by 1, itself and also 5. 65 is not a prime number 3. 71 71 ÷ 1 = 71 71÷ 71 = 1 71 can only be divided by 1 and itself. 71 is a prime number 4. 93 93 ÷ 1 = 93 93 ÷ 93 = 1 93 ÷ 3 = 31 93 can be divided by 1, itself and 3. 93 is not a prime number


Sieve Of Erastosthenes - A method of finding prime numbers between 1 to 100 (25 numbers) Step 1: list down all whole numbers between 1 to 100

  Whole numbers photo

Step 2: Cross out 1, because 1 is not a prime number. Step 3: Circle 2 and cross out all numbers that can divided by 2. Step 4: Circle 3 and cross out all numbers that can divided by 3. Step 5: Circle 5 and cross out all numbers that can divided by 5. Step 6: Circle 7 and cross out all numbers that can divided by 7. Step 7: Circle all remaining numbers and list down. The remaining numbers are the prime numbers between 1 to 100. Answer: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97.

2.4 Factors
- A factor of a given number is the number that can divide the given number exactly without any remainder. - The number 1 is a factor of all numbers. - Every number is a factor of itself - A whole number may have more than 2 factors. List all the factors of these numbers 1. 6 1 x 6 factors of 6 = 1, 2, 3, 6 2 x 3 2. 18 1 x 18 factors of 6 = 1, 2, 3, 6, 9, 18 2 x 9 3 x 6 3. 45 1 x 45 factors of 6 = 1, 3, 5, 9, 15, 45 3 x 15 5 x 9 4. 88 1 x 88 factors of 6 = 1, 2, 4, 8, 11, 22, 44, 88 2 x 44 4 x 22 8 x 11 Determine whether 1. 9 is a factor of 54 54 ÷ 9 = 6 (exact division, no remainder) Therefore 9 is a factor of 54 2. 7 is a factor of 48 48 ÷ 7 = 6 remainder 6 (not exact division) Therefore 7 is not a factor of 48


2.5 Prime Factors
- Prime factors of a given number are factors which are also prime numbers. - Example: Factors of 6: 1, 2, 3, 6 Prime numbers: 2 and 3 Prime factors of 6: 2 and 3 List all the prime factors of these numbers. 1. 24 Method 1 : List the factors Factors of 24 : 1, 2, 3, 4, 6, 8, 12, 24 Prime Factors : 2 and 3


Method 2 : Continuous Division




Determine whether
1. 2 is a prime factor of 18 18 ÷ 2 = 9 (exact division, no remainder) Therefore 2 is a prime factor of 18 2. 7 is a factor of 46 46 ÷ 7 = 6 remainder 4 (not exact division) Therefore 7 is not a prime factor of 46 3. 4 is a factor of 200 200 ÷ 4 = 50 (exact division, no remainder) 4 is a factor of 200 but 4 is not a prime number Therefore 4 is not a prime factor of 200


.6 Common Factors & Highest Common Factors (HCF)

Common Factors - Common factor is a number that is a factor of two or more numbers. - 1 is a common factor of all numbers. Find all the common factors of these numbers. 1. 8 and 12 Factors of 8 : 1, 2, 4, 8 Factors of 12 : 1, 2, 3, 4, 6, 12 Common factors of 8 and 12 : 1, 2, 4 2. 6, 12 and 18 Factors of 6 : 1, 2, 3, 6 Factors of 12 : 1, 2, 3, 4, 6, 12 Factors of 18 : 1, 2, 3, 6, 9, 18 Common factors of 6, 12 and 18: 1, 2, 3, 6 3. 27, 36 and 81 Factors of 27 : 1, 3, 9, 27 Factors of 36 : 1, 2, 3, 4, 6, 9, 12, 18, 36 Factors of 81 : 1, 3, 9, 27, 81 4. Common factors of 27, 36 and 81: 1, 3, 9 Determine whether 1. 6 is a common factor of 12, 18 and 24 12 ÷ 6 = 2 (exact division, no remainder) 18 ÷ 6 = 3 (exact division, no remainder) 24 ÷ 6 = 4 (exact division, no remainder) Therefore 6 is a common factor of 12, 18 and 24 2. 9 is a common factor of 63 and 120 63 ÷ 9 = 7 (exact division, no remainder) 120 ÷ 9 = 13 remainder 3 (not exact division) Therefore 9 is a not common factor of 63 and 120
Highest Common Factors ( HCF )
-
HCF of two or more numbers is the largest common factor of these numbers.




2.7 Multiples
- The multiples of a number is the product of that number with any whole number except
zero.
- Multiples are also a sequence.

List the first five multiples of these numbers.
1. 3
3 x 1 = 3
3 x 2 = 6
3 x 3 = 9
3 x 4 = 12
3 x 5 = 15
The first five multiples of 3 are 3, 6, 9, 12 and 15

2. 9
9 x 1 = 9
9 x 2 = 18
9 x 3 = 27
9 x 4 = 36
9 x 5 = 45
The first five multiples of 3 are 9, 18, 27, and 45


List all the multiples of these numbers.
1. Multiples of 2 between 13 to 27
14, 16, 18, 20, 22, 24, 26

2. Multiples of 5 from 50 to 70
50, 55, 60, 65, 70

Determine whether
1. 48 is a multiple of 4
48 ÷ 4 = 12 (exact division, no remainder)
Therefore 48 is a multiple of 4

2. 26 is a multiple of 3
26 ÷ 3 = 3 remainder 2 (not an exact division, has remainder)
Therefore 26 is not a multiple of 3


2.6 Common Multiples & Lowest Common Multiples (LCM)

Common Multiples
- Common multiple is a number that is a multiple of two or more numbers.
- Example 8 is a common multiple of 2 and 4
Multiple of 2 : 2, 4, 6, 8, 10, 12 ,… ( 8 is multiple of 2 )
Multiple of 4 : 4, 8, 12, 16, 20, … ( 8 is multiple of 4 )
Therefore 8 is a common multiple of 2 and 4

Find the first three common multiples of these numbers.
1. 2 and 3
Multiple of 2 : 2, 4, 6, 8, 10, 12 , 14, 16, 18, 20, …
Multiple of 3 : 3, 6, 9, 12, 15, 18, 21, 24, …
Therefore the first three common multiples of 2 and 3 are 6, 12, and 18


2. 3, 4 and 6
Multiple of 3 : 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36,..
Multiple of 4 : 4, 8, 12, 16, 20, 24, 28, 32, 36, ..
Multiple of 6 : 6, 12, 18, 24, 30, 36, ..
Therefore the first three common multiples of 3, 4 and 6 are 12, 24 and 36

Determine whether
1. 50 is a common multiple of 2 and 5
50 ÷ 2 = 25 (exact division, no remainder)
50 ÷ 5 = 10 (exact division, no remainder)
Therefore 50 is a common multiple of 2 and 5

2. 120 is a common multiple of 3, 4 and 9
120 ÷3 = 40 (exact division, no remainder)
120 ÷4 =30 (exact division, no remainder)
120 ÷ 9 = 13 remainder 3 (not exact division)
Therefore 120 is not a common multiple of 3, 4 and 9
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Lowest Common Multiples ( LCM )
- LCM of two or more numbers is the smallest common multiple of these numbers.

Find the LCM of the followings.
1. 6 and 36
Method 1 : Listing the multiples
Multiple of 6 : 6, 12, 18, 24, 30, 36, .
Multiple of 9 : 9, 18, 27, 36, …
The LCM of 6 and 9 is 18

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whole number lesson






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