NEW ENERGY ASSESSMENT STANDARDS

ASME will publish four new standards this month that establish requirements for conducting energy assessments at industrial facilities.




Improving the efficiency of industrial systems increases profitability and reliability, and makes better use of assets. Many industrial facilities have the potential to increase the efficiency of their systems, but have difficulty doing so because there is no market definition for energy efficiency assessment services. Lack of a definition creates problems for service providers in establishing market value for their services and for consumers in determining the relative quality of assessment services.



The standards establish procedures for assessments of a facility's entire systems, from energy inputs to the work performed.



The four standards to be published are:



ASME EA-1-2009 Energy Assessment for Process Heating Systems.



ASME EA-2-2009 Energy Assessment for Pumping Systems.



ASME EA-3-2009 Energy Assessment for Steam Systems.



ASME EA-4-2010 Assessment for Compressed Air Systems.



The energy assessment standards are intended to assist plant personnel in identifying cost-effective projects that often have limited capital requirements. They address the topics and requirements for organizing and conducting assessments, analyzing the data collected, and reporting and documentation.



An assessment may also include recommendations for improving resource utilization, reducing per-unit production cost, and improving environmental performance. These recommended practices will be provided in Guidance Documents which ASME expects to publish by mid-2010.



The new standards are a contribution to the framework for assisting U.S. industry to meet the energy intensity improvement criteria of Superior Energy Performance, the program of the U.S. Council for Energy-Efficient Manufacturing, a partnership of U.S. industry, government, and other organizations.



ASME made four Draft Standards for Trial Use available in late 2008 and asked for comments. The systems assessment community offered extensive comments, and revisions were made to the draft standards and Guidance Documents to better reflect current practices, procedures, and improvements. RYAN CRANE

what is Aeronautics?...by NASA

Definition

Aeronautics is the study of the science of flight. Aeronautics is the method of designing an airplane or other flying machine. There are four basic areas that aeronautical engineers must understand in order to be able to design planes. To design a plane, engineers must understand all of these elements.

Design Process

1 Aerodynamics is the study of how air flows around the airplane. By studying the way air flows around the plane the engineers can define the shape of the plane. The wings, the tail, and the main body or fuselage of the plane all affect the way the air will move around the plane.

2. Propulsion is the study of how to design an engine that will provide the thrust that is needed for a plane to take off and fly through the air. The engine provides the power for the airplane. The study of propulsion is what leads the the engineers determine the right kind of engine and the right amount of power that a plane will need

3. Materials and Structures is the study of what materials are to be used on the plane and in the engine and how those materials make the plane strong enough to fly effectively. The choice of materials that are used to make the fuselage wings, tail and engine will affect the strength and stability of the plane. Many airplane materials are now made out of composites, materials that are stronger than most metals and are lightweight.

4. Stability and Control is the study of how to control the speed, direction, altitude and other conditions that affect how a plane flies. The engineers� design the controls that are needed in order to fly and instruments are provided for the pilot in the cockpit of the plane. The pilot uses these instruments to control the stability of the plane during flight.

Engineering and Science Careers at NASA

What are the different kinds of careers in aerospace?

NASA Engineering Teams consist of many individuals - engineers, technicians, and scientists and various support personal.

Engineering and Science Careers offer:

Challenging jobs Good pay and benefits Lasting and tangible products

Help to humankind Prestige and status Continued educational experiences

Scientists

Scientists are knowledge seekers. They are inquisitive, seeking answers to known questions and finding many more questions.

Astronomy Biology Chemistry Computer Economics Geology Materials Mathematics Medical Doctor

Meteorology Nutrition Oceanography Psychology Physics Physiology Sociology Statistics Systems Analysis

Engineers

Engineers are problems solvers. They are the people that make things work and make life interesting, comfortable, and fun.

Aerospace Architectural Astronautics Biomedical Chemical Civil Computer Electrical

Environmental Industrial Metallurgical Mechanical Nuclear Petroleum Safety Systems

Technicians

Technicians are skilled personnel. Their skills are necessary for the research and development activities of Engineers and Scientist.

Aerospace Aircraft Avionics Communications Electrical Electronic

Engineering Fabrication Materials Mechanics Modeling Pattern Making

Preparing for an Aerospace Career

Engineers, scientists, and technicians rely on years of accumulated creative and academic skills to be part of a NASA Engineering Team. The journey to become a team member started when you were born and has continued throughout your life. Most engineering, scientific, and technical jobs require not only a High School Diploma or equivalent, but an Associate, Bachelor, or Graduate Degree.

While you're in High School you should take:

Algebra Biology Calculus Chemistry Computer Applications / Programming

English Fine Arts / Humanities Foreign Language Geometry Physics Social Studies Trigonometry

For Engineering and Science, Advanced Placement or Honors level courses are recommended.

Technicians need to meet the same general High School requirements, but Advanced Placement or Honors courses are not necessary. Drafting, mechanics, electronics, or similar technical courses are also recommended.

College and Universities seek "well rounded" students. Extracurricular activities and part time or summer jobs are also important.

Education Beyond High School

To begin a career as an Engineer or Scientist you need to obtain a Bachelor's Degree from an accredited College or University. Courses are usually completed in four to five years for full time students. Universities also offer graduate programs where students can obtain Master's and Doctoral Degrees in Science and Engineering. A Master's program generally takes two years. An additional two to four years is needed to earn a Doctorate.

Technicians typically earn a two year Associate of Science degree. Some may continue for two more years to obtain a Bachelor's degree. A few complete a five year apprenticeship program offered at some NASA field centers.

Preparing to become a NASA Engineering Team member is difficult. It requires a considerable amount of time, energy, and dedication... but the rewards are worth it.

Steps Required to Perform a Finite Element Analysis

The finite element analysis (FEA) or finite element method (FEM) or computer aided engineering (CAE) is used widely. What is FEA? How CAE works? The article will discuss these all using a flow chart for a typical finite element analysis.



What is Finite Element Analysis?

The finite element analysis (FEA) or FEM is a problem solving approach for the practical (engineering)

Welding Inspection Methods Using Non Destructive Testing (NDT) Techniques

Welding is a well established process of joining metals together, and a great advancement on riveting. However, some welds failed when put under load, prompting a more thorough method of inspection of welded joints Nowadays there are various techniquesfor non-destructive testing of welds (NDT)



Introduction to Nondestructive Testing of Welding.

When I served my time in Harland and Wolff shipyard in Belfast in the 1960’s, welding had thankfully taken over from riveting. My old next door neighbour had been a riveter on the Titanic and was stone deaf due to the constant hammering of the pneumatic equipment used in those days.

Shell and Tube Heat Exchanger Design

Introduction

The flow pattern in a shell and tube heat exchanger is typically not exactly counterflow or parallel flow, as with a double pipe heat exchanger. Rather, the flow pattern is typically some mix of counterflow, parallel flow and crossflow. The log mean temperature difference, which is used for shell and tube heat exchanger design, works for most of the varied flow patterns that occur in this type of heat exchanger. The general configuration and terminology for shell and tube heat exchangers is covered in 'Types of Shell and Tube Heat Exchangers'. This article will pick up from there.

Shell and Tube Heat Exchanger Flow Patterns

Instead of simply one pipe inside another, as for a double pipe heat exchanger, a shell and tube heatexchanger uses multiple tubes in a bundle inside of a 'shell'. This gives a more compact heat exchanger for a given heat transfer area, but the flow patterns are somewhat more complicated for a shell and tube heat exchanger. The diagram at the left shows the general configuration. Some of the shell and tube heat exchanger options that affect the flow pattern are U-tube or straight tube and how many passes (tube side). The shell side flow pattern is determined by baffles as shown in the diagrams.

A u-tube shell and tube heat exchanger has the tube side fluid entering and exiting at the same end of the heat exchanger, with the fluid making a 'u-turn' through tube bends at the other end, as shown in the upper diagram at the right. A u-tube shell and tube heat exchanger will automatically have two tube passes.

A straight tube shell and tube heat exchanger has a tube sheet and a plenum at both ends as shown in the lower two diagrams. The straight tube heat exchanger shown at the right has one tube pass and the one on the left has two tube passes.





Shell and Tube Heat Exchanger Design

The required heat transfer surface area for a shell and tube heat exchanger design is typically found from the basic heat exchanger equation: Q = UA ΔTlm, where:



Q = rate of heat transfer between the two heat exchanger fluids, Btu/hr,



U = overall heat transfer coefficient, BTU/hr-ft2-oF,



A = heat transfer surface area, ft2,



ΔTlm = log mean temperature difference in oF, calculated from the inlet and outlet temperatures of the two fluids.



The basic heat exchanger equation, and the above parameters, are discussed in 'Fundamentals of Heat Exchanger Design'. An example calculation with the basic heat transfer equation is given in 'Preliminary Heat Exchanger Design Example'.



If the required flow rate and temperature change of one of the fluids is known along with the flow rate and one temperature for the other fluid (or both temperatures for the other fluid), an estimate for the heat transfer coefficient, and the shell and tube heat exchanger flow pattern to be used, then the required heat transfer area can be calculated using the basic heat exchanger equation.



After the needed heat transfer surface area is calculated, an appropriate diameter, length and number for the tubes can be determined and the shell can be sized and designed. The tube sheets and baffles will also need to be designed.

Safety Devices in Air Conditioning and Refrigeration Plants

Compressor Safety

A compressor in a refrigeration or air conditioning plant has to be provided with some safeties to protect it from operational faults. The three common safeties provided are the high pressure trip, the low pressure trip, and the low oil pressure trip among the others. A compressor has to be protected against high pressure that can cause structural failure therefore a high pressure cut out is provided, similarly any deficiency in the oil pressure can damage the bearings and a low oil pressure cut out has to be provided, a lower atmospheric in the pipe line can cause air ingress and therefore must be avoided. In this article we discuss the different safeties one by one.



High Pressure Cut Out

High pressure can be caused in a refrigeration plant due to various causes like over charge, loss of cooling water, high ambient temperature, air, or other incompressible gases in the system, and obstruction in the discharge line of the compressor. For protecting the compressor from high pressure and subsequent failure, a high pressure cut out is provided that take a pressure tapping from the discharge line and when it detects an over pressure, it stops the compressor. The HP cut out is not resettable automatically but has to be reset manually by the operator. This is because the high pressure is a serious fault and the cause must be investigated and corrected before the plant is started again.



Construction of High Pressure Cut Out



Operation of a High Pressure Cut Out

The high pressure cut out as shown in the diagram is of a simple construction. It has a bellows that is set against a spring. The nut at the end of the spring is used to adjust the cut out pressure. When the high pressure gas enters the bellow, the bellow expands and presses the spring. At the cut off pressure the movement of the bellow against the spring releases the catch and the contact is broken and the compressor cuts off.



The switch arm can be pressed and the cut out reset after the cause of the over pressure has been found and rectified.



Low Pressure Cut Out

To protect the compressor against low pressure in the system and to avoid the ingress of air into the system if a vacuum is generated in the lines a low pressure cut out is provided. Also when the refrigerated compartments are cut off by the solenoids and there is no return gas, the low pressure cut out is activated. When the solenoid of the refrigerated compartments open, the return gas comes in the inlet of the compressor and the suction pressure rises, and then the low pressure switch cuts in the compressor.



Unlike the high pressure cut out, the low pressure cut out is self-resettable and does not need to be reset manually.



Low Pressure Cut Out Layout



Low Oil Pressure Cut Out

The oil is pumped under pressure by an attached oil pump that supplies oil to the bearings for lubrication. Any problem in the lube oil pressure can jeopardize the bearings and therefore a tapping is taken from the pump outlet and fed to the oil pressure switch. Any fall in the pressure will activate the cut out which will stop the compressor.



Oil Separator

As oil is miscible with the refrigerant and often goes out of the compressor with it, it can go to the evaporator where it can cause a decrease in heat transfer. To avoid the oil from going to the evaporator where it can form a layer inside or cause obstruction an oil separator is used. It basically consists of baffle plates that separate the oil from the refrigerant and feed it back to the compressor. A float valve is provided so that short circuiting of the refrigerant should not take place.



Oil Separator Construction



Conclusion

The refrigeration plant compressor has to be protected against unnatural working conditions by safety devices and controls. The high pressure cut out, the low pressure cut out, and the low oil pressure cut out are some of the basic protective devices provided. In large complex circuits other additional safety devices are provided according to the complexity of the circuit.

Differences in a Nuclear and Coal Fired Power Plant Steam Cycle

The nuclear power plant and the fossil thermal power plant both use steam to convert the heat or thermal energy to mechanical rotation to rotate the generator to produce electricity. Only the heat source is different. In a nuclear plant, the heat source is from the nuclear reaction whereas in a thermal power plant it is from the combustion of coal.



The difference is in the inlet steam parameters to the turbine in a nuclear plant. Thermal power plants use steam at superheated conditions. In nuclear plants, the steam is at saturated conditions and at a lower pressure. This is due to the inherent design limitations in the nuclear reactors.



In fossil power plants the inlet steam parameters are typically temperatures of 540 º C to 580 º C and pressures of 170 bar or even higher. In addition, there is additional heating in the form of re-heating. In a nuclear plant, the ratings are typically saturated steam at 78 bar, which is steam temperature of 298 º C. The nuclear plant uses a 'wet steam turbine'.



Increased Steam Flow.

The reduced inlet steam parameters in the nuclear plant results in lower thermal efficiencies. Nuclear plants operate at lower thermal efficiencies , lower by more than 10 %. The energy of steam per unit mass entering the turbine is also less.



This results in a very high steam flow for the same MW output, almost double that of fossil power plants.



The configurations of the turbines change due to this. The economics of scale requires the nuclear plants to be in the range of 600 MW to 1000 MW resulting in very big Turbines.



Fossil plants turbines normally have one High Pressure one Intermediate Pressure and a double flow Low Pressure (LP) cylinder.



The LP turbine exhausts to very low pressure. The volume of steam leaving the LP turbine is very high. The higher flows require very long last stage blades to keep the exit velocities and exit loss very low. This results in very high stresses in the blades. The sizing of the LP turbine is limited due to the size of the Last Stage Blades. Therefore, each LP turbine has a flow limitation.



One way to overcome this limitation is to increase the number of LP turbines. Large Nuclear plants have apart from an HP /IP stage two or three double flow LP turbines connected in tandem.



Another way is to reduce the speed. Since the stress on the Last Stage Blades is speed dependent reducing the turbine speed by half reduces the stress resulting in bigger sized LP turbines. In such cases the turbine runs at 1500 or 1800 rpm. This requires specially designed four pole generator rotors. This results in a lower number of LP turbines. This is more helpful in 60 Hz countries.



Wet Steam

Nuclear steam turbines are 'wet steam turbines'.



Since the steam is at saturated conditions, after each stage expansion the steam gets wetter. The water particles result in lower efficiency of the turbine. This results in erosion damage to the blades. In addition, this results in vibrations and stress in the last stage. To overcome this nuclear steam turbines use special design of blades and flow paths.



Moisture separators located in the steam path at exit of HP / IP and in the cross under pipes reduce the undesirable effects of the moisture in the steam. Moisture Separator Reheaters also are used. These use extracted steam to aid in moisture removal.



No Reheating

Nuclear steam cycles do not have Reheating as in fossil units. This also reduces the cycle efficiency.
Even with the much lower thermal efficiency, Nuclear power is feasible due to low unit cost of fuel.

DEFENSE PLANS

.Combine advances in computer models and predictions about group behavior with upgraded video game graphics, and you'll have a virtual world in which defense analysts can explore and predict results of possible military and policy actions, according to computer science researchers at the University of Maryland. The researchers published a commentary on computer predictions in the Nov. 27, 2009, issue of the journal Science.




"Defense analysts can understand the repercussions of their proposed recommendations for policy options or military actions by interacting with a virtual world environment," wrote V. S. Subrahmanian. He's a computer science professor at the university and director of the school's Institute for Advanced Computer Studies.



He and John Dickerson, computer science researcher at the university in College Park, authored the commentary.



Virtual technology can help defense analysts propose policy options and walk skeptical commanders through a virtual world - a world in which one can literally see how things might play out, the pair wrote.



"This process gives the commander a view of the most likely strengths and weaknesses of any particular course of action," they said. "Computer scientists now know pretty much how to do this, and have created a pretty good chunk of the computing theory and software required to build a virtual Afghanistan, Pakistan, or another world.



"Human analysts, with their real world knowledge and experience, will be essential partners in taking us the rest of the way in building these digital worlds and then in using them to predict courses of action," the researchers wrote.

NEW ENERGY ASSESSMENT STANDARDS

ASME will publish four new standards this month that establish requirements for conducting energy assessments at industrial facilities.




Improving the efficiency of industrial systems increases profitability and reliability, and makes better use of assets. Many industrial facilities have the potential to increase the efficiency of their systems, but have difficulty doing so because there is no market definition for energy efficiency assessment services. Lack of a definition creates problems for service providers in establishing market value for their services and for consumers in determining the relative quality of assessment services.



The standards establish procedures for assessments of a facility's entire systems, from energy inputs to the work performed.



The four standards to be published are:



ASME EA-1-2009 Energy Assessment for Process Heating Systems.



ASME EA-2-2009 Energy Assessment for Pumping Systems.



ASME EA-3-2009 Energy Assessment for Steam Systems.



ASME EA-4-2010 Assessment for Compressed Air Systems.



The energy assessment standards are intended to assist plant personnel in identifying cost-effective projects that often have limited capital requirements. They address the topics and requirements for organizing and conducting assessments, analyzing the data collected, and reporting and documentation.



An assessment may also include recommendations for improving resource utilization, reducing per-unit production cost, and improving environmental performance. These recommended practices will be provided in Guidance Documents which ASME expects to publish by mid-2010.



The new standards are a contribution to the framework for assisting U.S. industry to meet the energy intensity improvement criteria of Superior Energy Performance, the program of the U.S. Council for Energy-Efficient Manufacturing, a partnership of U.S. industry, government, and other organizations.



ASME made four Draft Standards for Trial Use available in late 2008 and asked for comments. The systems assessment community offered extensive comments, and revisions were made to the draft standards and Guidance Documents to better reflect current practices, procedures, and improvements. RYAN CRANE

Financial Aid For Students: Merit-Based And Need-Based

Expenses on education and college life cannot be controlled even by the most reliable calculators. There are always some unpredictable situations that require more money to be spend, more activities to be taken, and more ideas to be used. This is why the idea of offering students some kind of financial aid is regarded as winning and necessary all the time.




Classification into Categories



Financial aid for students in colleges may be classified into two main groups: need-based and merit-based. Each of these categories has its own peculiarities and demands. In respect to these bases, different financial aid as well as different conditions of support is offered to students.



About merit-based financial aid…



This kind of financial aid is usually awarded to students as a result of their special skills, certain achievements in education or sport, demonstration of their talents, and other abilities that are helpful to college society.



The peculiar feature of merit-based help is the necessity to compete. The idea that someone deserves this financial aid more than other person does becomes a crucial point. It is necessary to choose the best and rely on a superior criterion. However, it is not the only one criterion that has to be admitted.



Such points like field of study, leadership skills, religion, ethnicity, and even community service are taken into consideration before the decision to provide a student with this merit-based financial help is made.



About need-based financial aid…



It happens that some students feel unbelievable financial need all the time. This is why they try to submit the FAFSA as soon as possible and get an opportunity to be financially supported by the government. In this case, no competitions should take place because it sounds senseless to compete and clear up who has the worst financial position.



Need-based help plays a very important role in the educational processes. Many students, who are eager to study but deprived of the opportunities, get such chance and continue their education to enlarge their level of knowledge and become professionals in the chosen spheres.