Testing Your Pressure

To get the best performanee and the longest life out of the tires on your ear, you want to maintain the rcommended air pressure. To find out whether your tires are at the optimal pressure, you do a simple test or you have the serviee station do so. The same applies to the pressure on your heart and in your arteries. The first step is to have a simple, painless test done in your doctor s office. 

Most men and women have had their blood pressure measured at one time or another. But, bearing in mind that without knowing it, many individuals have either pressure above optimal levels or frank hypertension, if you haven t had a test lately, call your doctor s office and schedule an appointment. While you re there, it would be a good idea to have your cholesterol levels checked as well. Elevated cholesterol counts are not only a major risk factor for heart attack and stroke, in and of themselves, but they also predispose a person to developing hypertension. 

To test blood pressure, the doctor or another health professional inflates a cuff placed around the arm above the elbow. He or she then listens for specific sounds through a stethoscope placed at the crook of the elbow as the cuff is gradually deflated. The first of those sounds signals the time the heart beats and the fifth and final sound notes the heart at rest between beats. The pressure at the time of those two sounds is noted in a column of mercury similar to that in a thermometer, on a device called a sphygmomanometer, which is frequently mounted on the wall. The first, beating pressure 

Some medical offices now use a digital apparatus to test blood pressure, reducing the environmental impact of mercury. But the mercury sphygmomanometer is still considered the gold standard and is used to calibrate the accuracy of other devices. 

Many things affect blood pressure, so it s best to have at least two and preferably three measurements done while you re in the doctor s office. To make a diagnosis of hypertension, rather than merely of somewhat elevated levels, the doctor should test your blood pressure during three separate office visits. 

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Here are a few things you can do to make sure your test is as accurate as possible. Get a good night s sleep the night before your visit. Wear a shirt or a blouse that can be easily rolled up on the arm so the cuff can be placed on bare skin. Sit with both feet on the floor. Ideally, relax for a few minutes before the test by taking a few deep breaths and thinking happy thoughts. If you re in the doctor s office for some other reason, ask to have your pressure measured at the end, rather than the start, of your appointment. 

Test your program by fitting the data for ethylene glycol given in Problem 6.4. Then use your formula to estimate the vapor pressures of this substance at 50 C, 80°C, and 110°C, and the boiling points at 760 mm Hg and 2000 mm Hg. In which of the last two values would you have the least confidence Explain your reasoning. 

Consider the reaction 2A — B. Derive an analytical expression for the fraction unreacted in a gas phase, isothermal PFR of length L. The pressure drop in the reactor is negligible. The reactor cross section is constant. There are no inerts. The feed is pure A and the gases are ideal. Test your mathematics with a numerical solution. 

Modify the Mathcad program of Figure 6.3 for ternary mixtures. Test your program with the data presented in Example 6.2 for a mixture of benzene (A), toluene (B), and o-xylene (C). Critical temperatures and pressures, and the parameters of the Wagner equation for estimating vapor pressure (equation 6-5), are included in the following table (Reid et al., 1987). 

Okay, says the cardiologist after he reviews the results of the tests, conducted by the nurse and a junior associate. He himself has spent just ten minutes with this patient, and already he s late for his next appointment. Here s something to help your cholesterol go down, and something for your pressure. You shouldn t have many side effects, though you might experience some memory problems, and, of course, a loss of sex drive. But I wouldn t worry about it. Good luck, and I ll see you in three months when your prescription runs out. ... 

This problem specifically tests your knowledge of Boyle s law. We know that PFis a constant, provided that the temperature is kept constant. Since the temperature is constant, we can readily apply Boyle s law. We can equate the initial and final stages of the system. and F represent the initial pressure and volume respectively. P and F represent, the final pressure and volume respectively. 

You ean see, ba.sed on the veloeity head formula, a eavitation bubble impacts the impeller and other pump parts at about 155,069 psi. Other experiments in test laboratories using a more preeise rHv, have calculated the impact pressure at 1 Gigapascal, or 147,000 psi. This is the reason that the damage from eavitation appears like someone was beating on your impeller with a large ball pein hammer. 

This requirement hides an important provision. It not only applies to inspection, measuring, and test equipment but to the measurements that are performed with that equipment. Anywhere you intend performing product verification or monitoring processes you need to ensure that the environmental conditions are suitable. By environmental conditions is meant the temperature, pressure, humidity, vibration, lighting, cleanliness, dust, acoustic noise, etc. of the area in which such measurements are carried out. To avoid having to specify the conditions each time, you need to establish the ambient conditions and write this into your procedures. If anything other than ambient conditions prevail, you may need to assess whether the measuring devices will perform adequately in these conditions. If you need to discriminate between types of equipment, the ones most suitable should be specified in the verification procedures. 

Do not assume that such things could not happen in your company (unless you have spent some time in the relief-valve workshop). All relief valves should be tested and inspected regularly. Reference 3 describes model equipment and procedures. When a large petroleum company introduced a test program, it was shocked by the results out of 187 valves sent for testing, 23 could not be tested because they were leaking or because the springs were broken, and 74 failed to open within 10% of the set pressure—that is, more than half of them could not operate as required [4]. 

Self-Test 8.1A Which do you expect to have the higher vapor pressure at room temperature, tetrabromomethane, CBr4, or tetrachloromethane, CC14 Give your reasons. 

A thick slurry with SG= 1.3 is to be pumped through a 1 in. ID pipe that is 200 ft long. You don t know the properties of the slurry, so you test it in the lab by pumping it through a 4 mm ID tube that is 1 m long. At a flow rate of 0.5 cm3/s, the pressure drop in this tube is 1 psi, and at a flow rate of 5 cm3/s it is 1.5 psi. Estimate the pressure drop that would be required to pump the slurry through the 1 in. pipe at a rate of 2 gpm and also at 30 gpm. Clearly explain the procedure you use, and state any assumptions that you make. Comment in detail about the possible accuracy of your predictions. Slurry SG= 1.3. 

A rotary drum filter is to be installed in your plant. You run a lab test on the slurry to be filtered using a 0.1 ft2 sample of the filter medium at a constant pressure drop of 10 psi After 1 min you find that 500 cm3 of filtrate has passed through the filter, and after 2 min the filtrate volume is 715 cm3. If the rotary drum filter operates under a vacuum of 25 in.Hg with 25% of its surface submerged, determine ... 

If a rubber tube connected to the vacuum source and the system (or manometer) collapses, you ve had it. The system is no longer connected to the vacuum source, and as air from the bleed tube or vapor from the liquid you re distilling fills your distillation setup, the pressure in the system goes up. Occasionally test the vacuum hoses and if they collapse under vacuum, replace them with sturdier hoses that can take it. 

Form a hypothesis about how the pressure inside the test tube is related to the production of carbon dioxide during the reaction. Refer to the ideal gas law in your explanation. 

Bring the pressure of the air in the eudiometer to atmospheric. How can this be done Calculate the molecular mass of the liquid being tested and enter the results in your laboratory notebook, using Form 3 for this purpose. 

Adjust the pressure of the gas in the test tube to atmospheric, mark the level of the water with a rubber band, and determine the volume of the evolved gas with a small measuring glass. Enter the cesults in your laboratory notebook using Form 13. 

Seal off offtake 2 and spill metallic zirconium into section 5 via offtake 6. Tightly close offtake 6 with a rubber stopper. Connect the apparatus via offtake 8 to a vacuum system for 15-20 min. Next place test tube 1 into a Dewar vacuum flask with liquid nitrogen and seal off offtake 6. Perform this work wearing eye protection in the presence of your instructor ) After the pressure in the system becomes equal to 10 mmHg (in about 40-60 minutes), seal off offtake 8. Stop cooling test tube 1 and wait until the apparatus acquires room temperature. 

Properties interact with the end product requirements such as product size, flowability through the mold and cycle times to determine necessary pressure and output requirements of the processing equipment. To begin your chemical system selection, write a performance specification for the product. Recommended formulations for specific product types have been thoroughly tested and evaluated by the chemical companies selling them. The chemical companies can provide you with the physical property data of the formuladon. 

With vacuum/pressure the conveying action provides double the conveying rates of vacuum alone. Plastic lines are not recommended for conveying lines since static electricity will be generated and will interfere with the movement of plastics. A rather simple and useful test to determine if material is going to be difficult to convey can be used. Take a handful of the plastic and squeeze it firmly. Upon opening your hand, if the lines in your palm are filled with fines, it will be difficult. 

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