IS THERE ANY RELATION SHIP BETWEEN DEW POINT AND PRESSURE With a low pressure system you will get rain/ snow. Dew point is the relative

Shantanu Lanke

IS THERE ANY RELATION SHIP BETWEEN DEW POINT AND PRESSURE With a low pressure system you will get rain/ snow. Dew point is the relative

temperature at which it will rain. Thus, a low pressure will make the dew point rise or decrease depending on the Temperature at which it needs to be in order to rain. When it comes to temperature the warmer it is the more saturated the the atmosphere is and thus if we up/down the dew point it will rain. Keep in mind the higher the dew point the higher the temperature needs to be to rain. Higher DP= higher saturation. When it comes to high pressure that deals with relatively calm/stable weather, because of the lowering of air. Thus, lower dew point.

ah.yehia

Can u explaine uses of ester

esters are commercially used as the flavoring agents and lower esters are ued as the solvents. for example, n-octyl acetate is used as orange flavor, amyl and isoamyl acetate is used for banana flavor,methyl butyrate is used for apple or pineapple flavor, amyl valerate is used for apricot flavor and benzyl acetate is used for jasmine flavor

Shantanu Lanke

what is the relation between velocity and pressure... if they both are directly proportional...what do you say about venture meter where velocity increses when pressure decreases?

in venturimeter u measure the pressure perpendicular to the flow which is proportional to height. if velocity increases, diameter of pipe dereases and hence the height.

therefore u get a reduced pressure.

To explain this we need to consider two major equations Let us take

1. Bernoulli's equation:

P + (Rho)gy + (1/2)(Rho)v^2 const.

2.Continuity equation:

Which is to maintain constant flow rate QA1v1 A2v2

Considering flow is happening through a tapering pipe.

P pressure Section 1 Larger than Section 2

So when flow happens from section 1 to section 2 the area is decresing so the velocity will increase to maintain the constant flow rate by continuity equation.

So if you take Bernoulli's equation, to maintain constant value at one side the datum/height or the pressure has to be increased.

So Area decreases-->Velocity will increase-->Pressure increases.

So velocity and Pressure are inversely proportional unless the Datum/Height is same.

Hope this solves your query

ah.yehia

Mai i know what is the reason for having 2different system for pressure units i.e, kg/cm squ.

1 bar = 1.019368kg/cm2 1kg/cm2 = 0.9810bar

http://wiki.xtronics.com/index.php/Pressure_Conversion_Table ah.yehia

plz let me know the clear meaning of heat capacity & specific heat

The specific heat is the amount of heat per unit mass required to raise the temperature by one degree Celsius. The relationship between heat and temperature change is usually expressed in the form shown below where c is the specific heat. The relationship does not apply if a phase change is encountered, because the heat added or removed during a phase change does not change the temperature.

https://www.facebook.com/photo.php?fbid=566235160089579&set=a.4798264320637 86.109797.479381242108305&type=1&theater

The heat capacity of a defined system is the amount of heat (usually expressed in calories, kilocalories, or joules) needed to raise the system's temperature by one degree (usually expressed in Celsius or Kelvin). It is expressed in units of thermal energy per degree temperature. To aid in the analysis of systems having certain specific dimensions, molar heat capacity and specific heat capacity can be used. To measure the heat

capacity of a reaction, a calorimeter must be used. Bomb calorimeters are used for constant volume heat capacities, although a coffee-cup calorimeter is sufficient for a constant pressure heat capacity.

B.H

what is purging??

Purging is the process of adding a substance to an open system or releasing it, to go from one concentration to another, be it moisture, oxygen, or product purity. Purging a system to an inert state will render it safe from combustion or explosion as long as the inert state is maintained by blanketing.

The two main situations encountered in purging a chemical process include:

•Start up, where equipment containing air is to be placed into service

•Shut down, where equipment containing combustible gas or vapor is to be withdrawn from service

B.H

why vacuum pressure created in gas condensate distillation plant (re boiler & column) when ur vapors condense to liquid, pressure exerted by the the vapors is reduced and at the boiling point VP = atm press. therefore when vapor ondenses VP is reduced and u get a vacuum.

how the air filled in a cycle tube was not coming out?

check this

http://www.madehow.com/Volume-2/Bicycle.html#b

CAN U EXPLIN ME THE DIFFERENCE BETWEEN specific heat and heat capacity

The specific heat is the amount of heat per unit mass required to raise the temperature by one degree Celsius. The relationship between heat and temperature change is usually expressed in the form shown below where c is the specific heat. The relationship does not apply if a phase change is encountered, because the heat added or removed during a phase change does not change the temperature.

https://www.facebook.com/photo.php?fbid=566235160089579&set=a.4798264320637 86.109797.479381242108305&type=1&theater

The heat capacity of a defined system is the amount of heat (usually expressed in calories, kilocalories, or joules) needed to raise the system's temperature by one degree (usually expressed in Celsius or Kelvin). It is expressed in units of thermal energy per degree temperature. To aid in the analysis of systems having certain specific dimensions, molar heat capacity and specific heat capacity can be used. To measure the heat

capacity of a reaction, a calorimeter must be used. Bomb calorimeters are used for constant volume heat capacities, although a coffee-cup calorimeter is sufficient for a constant pressure heat capacity.

The unit for specific heat is J/(g*K). The unit for heat capacity is J/K. It should be simple how to go from one to another.

The biggest source of confusion is that a lot of people use the terms interchangeably.

Often times heat capacity is used to describe specific heat capacity, molar heat capacity, and volumetric heat capacity, even though that is not exactly correct.

B.H

wts ment by leadent heat of frost point

When water condenses, cools, or freezes, the temperature of the environment around the water rises because latent is changed to sensible heat. Latent heat is chemical energy stored in the bonds that join water molecules together and sensible heat is heat you measure with a thermometer. When latent heat is changed to sensible heat, the air temperature rises. When ice melts, water warms, or water evaporates, sensible heat is changed to latent heat and the air temperature falls. Table 1 shows the amount of heat consumed or released per unit mass for each of the processes.

can you please say physical and chemical properties of ethanol check this

http://www.ucc.ie/academic/chem/dolchem/html/comp/ethanol.html http://en.wikipedia.org/wiki/Ethanol_(data_page)

why cavitation is not happening in reciprocating pump...?if it is because of some extra devise why cant we make centrifugal pump...like that?

Cavitation is the formation and then immediate implosion of cavities in a liquid – i.e. small liquid-free zones ("bubbles") – that are the consequence of forces acting upon the liquid. It usually occurs when a liquid is subjected to rapid changes of pressure that cause the formation of cavities where the pressure is relatively low. Reciprocating pumps subject liquids to high pressures and not low pressures.

Cavitation occurs when the pressure on a liquid drops below the vapor pressure for the liquid or when gas is otherwise introduced to a pump such that it disrupts the flow of the liquid through the pump.

Positive displacement pumps trap a quantity of liquid (or gas) and then increase the pressure by pushing (displacing) it into the discharge pipe. External pressure pushes the liquid into the pump chamber which then is made smaller before the pump chamber discharges its contents. If any gas enters the pump chamber along with a liquid it is simply compressed along with the liquid. Positive displacement pumps work just fine with both gases and liquids - although when gases are being compressed it is usually necessary to cool the pump chamber which heats up quite a bit during the almost adiabatic compression step of the pump. Cavitation does not occur in part because the pressure in the pump chamber is almost completely uniform. If the compression chamber drops below the vapor pressure of a liquid being pushed into it, the external pressure will continue to push the liquid in, then when the pump begins to decrease the volume, the valve allowing the liquid to enter will close and the volume of the contents is decreased until the pressure rises back above the vapor pressure of the liquid and it condenses in the pump chamber.

A centrifugal pump uses a rotating impeller to increase the pressure and flow rate of a fluid.

In centrifugal pumps, pressure is added by increasing the kinetic energy of the liquid and then, in essence, "throwing" the liquid into the discharge pipe where the higher kinetic energy liquid pushes on the liquid ahead of it to increase pressure. As the impeller moves through the liquid being pumped, it pushes on the liquid ahead of it, imparting additional kinetic energy to it. The liquid behind the impeller, however, actually experiences a little bit of a drop in pressure as the impeller tries to move away from it. Because liquids are fairly incompressible, this usually does not create any problem and the internal pressure of the liquid is sufficient to keep it in contact with the backside of the impeller. If the drop in pressure is low enough that the pressure drops below the vapor pressure of the liquid at the temperature present in the pump, the liquid will begin to vaporize. Once gas is present in the pump, it begins to cavitate - the liquid separates from the back of the impeller - especially near the tips. For this reason, introducing air or other gas into the liquid can cause cavitation, even if the pressure never drops below the vapor pressure of the liquid being pumped. This is also why centrifugal pumps are usually "primed" prior to being started up - to get all, or at least most, of the gas out of the line so that the pump won't cavitate.

ah.yehia

Can you please say what are the safety precautions to be taken for preparation of ethyl alcohol from molasses fermentation

Fermentation is the process of culturing yeast under favorable thermal conditions to produce alcohol. This process is carried out at around 35–40 °C. Toxicity of ethanol to yeast limits the ethanol concentration obtainable by brewing; higher concentrations, therefore, are usually obtained by fortification or distillation. The most ethanol-tolerant strains of yeast can survive up to approximately 15% ethanol by volume.

To produce ethanol from starchy materials such as cereal grains, the starch must first be converted into sugars. In brewing beer, this has traditionally been accomplished by allowing the grain to germinate, or malt, which produces the enzyme amylase. When the malted grain is mashed, the amylase converts the remaining starches into sugars. For fuel ethanol, the hydrolysis of starch into glucose can be accomplished more rapidly by treatment with dilute sulfuric acid, fungally produced amylase, or some combination of the two.

Any good suggestion for my thesis? The topic should be related to petroleum refining because i am a scholar of a certain petroleum refining company. thank you

Platforming

Catalytic reforming is a chemical process used to convert petroleum refinery naphthas, typically having low octane ratings, into high-octane liquid products called reformates which are components of high-octane gasoline (also known as high-octane petrol).

Basically, the process re-arranges or re-structures the hydrocarbon molecules in the naphtha feedstocks as well as breaking some of the molecules into smaller molecules.

The overall effect is that the product reformate contains hydrocarbons with more complex molecular shapes having higher octane values than the hydrocarbons in the naphtha feedstock. In so doing, the process separates hydrogen atoms from the hydrocarbon molecules and produces very significant amounts of byproduct hydrogen gas for use in a number of the other processes involved in a modern petroleum refinery.

Other byproducts are small amounts of methane, ethane, propane, and butanes.

i need picture of High Temperature and low temperature shift converter in ammonia plant, can you send me this picture please.

check this is very useful

http://www.mediafire.com/download/2cys6yzxiiwyv6t/HT_and_LT.rar

ah.yehia

1micron=---???---m

micron equal 1×10^−6 of a metre

http://en.wikipedia.org/wiki/Micrometre

what is hagen and poiseuille laws?

Hagen–Poiseuille equation is a physical law that gives the pressure drop in fluid flowing through a long cylindrical pipe. The assumptions of the equation are that the flow is laminar viscous and incompressible and the flow is through a constant circular cross-section that is significantly longer than its diameter. It is also known as the Hagen–

Poiseuille law, Poiseuille law and Poiseuille equation.

V = ( pi * p * R4 ) / ( 8 * n * l ) V = Volume per Second

P = Pressure Difference Between The Two Ends R = Internal Radius of the Tube

n = Absolute Viscosity L = Total Length of the tube

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B.H

what is the difference between heat and temperature THE DIFFERENCE BETWEEN TEMPERATURE AND HEAT:

There is a fundamental difference between temperature and heat. Heat is the amount of energy in a system. The SI units for heat are Joules.Heat is transferred through radiation, conduction and convection. The amount that molecules are vibrating, rotating or moving is a direct function of the heat content. When first added to a substance, energy might be concentrated in one atom, but this one will soon bump into others and spread the energy. Eventually, every atom or molecule in the substance will move a bit faster. When the added energy is spread throughout a substance, it is then called heat energy,

thermal energy.

TEMPERATURE:

Temperature is the MEASURE of the AVERAGE molecular motions in a system and simply has units of (degrees F, degrees C, or K). Notice that one primary difference between heat and temperature is that heat has units of Joules and temperature has units of (degrees F, degrees C, or K). Another primary difference is that energy can be

transported without the temperature of a substance changin.But, as a general statement , as heat energy increases, the temperature will increase. If molecules increase in

vibration, rotation or forward motion and pass that energy to neighboring molecules, the measured temperature of the system will increase.

B.H

which software should i use to draw process flow diagrams ? it can help you

http://www.edrawsoft.com/flowchart.php

what is difference between pressure and pressure energy . and also explain relation between pressure and area , pressure energy and area

#Pressure is defined as force per unit area. It is usually more convenient to use pressure rather than force to describe the influences upon fluid behavior. The standard unit for pressure is the Pascal, which is a Newton per square meter.

#Pressure as Energy Density:

Pressure in a fluid may be considered to be a measure of energy per unit volume or energy density. For a force exerted on a fluid, this can be seen from the definition of pressure.

The most obvious application is to the hydrostatic pressure of a fluid, where pressure can be used as energy density alongside kinetic energy density and potential energy density in the Bernoulli equation.

http://water.me.vccs.edu/courses/CIV240/lesson9.htm B.H

how the problem of flooding in a distillation column is confronted in an industry?

Flooding

Flooding is brought about by excessive vapour flow, causing liquid to be entrained in the vapour up the column. The increased pressure from excessive vapour also backs up the liquid in the downcomer, causing an increase in liquid holdup on the plate above.

Depending on the degree of flooding, the maximum capacity of the column may be severely reduced. Flooding is detected by sharp increases in column differential pressure and significant decrease in separation efficiency.

controlling flow-rates of feed and refluxes and controlling tower temperature to control flow of vapor and liquid into the column

ah.yehia

What is the diffrence between vapour & steam

vapor is of any volatile liquid while steam is the vapor of only water at its boiling point vapor need not to occur only at boiling pt whereas stem is always at boiling pt of water of greater.

Steam refers to the gaseous phase of water which is formed when water boils while water vapour refers to the gas phase of water. The difference between steam and water vapour is that water vapour can be produced from the evaporation or boiling of liquid water or from the sublimation of ice while steam is only formed from boiling water.

ah.yehia

Difference between vacuum and pressure Differences:

To get the difference between pressure and vaccum , one must use both the terms in a common situation. So to clear this, have an example of piston-bottle arrangement(very much like the case in reciprocating or cylinder engine).

So in this case whenever user applies a pressure over it, the inner air gets densed and in the other end, if user tries to take piston out , in the same condition, the inner air gets less denser. Means by the second activity , a VACCUM is going to create in between the bottle.

So we can deduce that vaccum is reciprocal to pressure, means

more the pressure => more the air density in between => No longer Vaccum Exist but

Negating the Pressure => Less the air density in between => Vaccum is established.

Such thing can be observed in Injections, if you block the needle end and try to elongate the other end by akichning it.

http://entrance-exam.net/forum/general-discussion/difference-between-pressure-vacuum-what-formula-details-about-conversion-units-110068.html

ah.yehia

how to creat a place of artificial gravity...?what r the different things to be considered..

why does the sphere gives more surface area and volume than any other shaped object