Vacuum equipment

Nigerians Night blindness Night vision Night vision devices Night vision equipment Night-vision optics Nigre soap Nigrosine Nigrosine dyes Nigrosines  [c.674]

Photodetector devices convert electromagnetic radiation or photons to electric signals which can be processed to obtain the spectral, spatial, and temporal information inherent in the radiation. Photodetectors, as indicated in Table 1, may be operated in many modes. The more popular ones are photoconductors, photodiodes, charge-transfer devices, and the pyroelectrics. The detectors may be used as single elements such as in street light controls, film camera exposure control, or motion detectors for security, or in the form of linear arrays used in analytical spectrometers, night-vision equipment, or configured as large matrix arrays found in video cameras. By the twenty-first century, photodetectors are expected to appear in small, low cost spectrometers for the control of building ventilation and environmental pollution monitoring. Detectors using artificially stmctured materials such as semiconductor supedattices and high temperature superconductors are in the early development stage as of this writing (ca 1995).  [c.419]

Many aspects of the performance of military pyrotechnics are measured and analyzed by modem instmmental techniques such as spectrophotometers for light intensity studies, replacing the quaHtative, visual evaluations that were formerly used for acceptance of these devices. MiHtary pyrotechnics ate also experiencing a shift away from a concentration on the visible region of the electromagnetic spectmm, and are moving into the generation and obscuration of the infrared and microwave/millimeter regions, as modem techniques such as heat-seeking missiles, thermal imaging systems, and night vision equipment have dramatically altered the battlefield scenario. Pyrotechnic devices, such as screening smoke units, have had to adjust with these changes in technology to remain viable and effective. There will undoubtedly be mote changes in pyrotechnics as modem warfare becomes more and more instmmental rather than visual in nature.  [c.350]

Filler metal forms include soHd preforms and powders, used mosdy in the compound form of paste, plastic-bonded tape, and, in the case of soldering, rosin core wire. In special soldering appHcations, solders may be used as a Hquid medium of the soldering baths in which electronic boards are immersed for a short time to solder multiple joints. Conventional paste forms of joining alloys, eg, FM powder plus fluxing agent plus binder/solvent, ate appHed at externally accessible locations of the clearance between BM pieces. Such practice requites substantial FM fluid flow during joining to achieve fusion of constituent FM phases and binder/solvent extraction. In addition, organic binders decompose when compound FM forms are used in the high vacuum brazing of parts intended for critical high temperature service. Such decomposition of binders can result in the formation of soot in the joint, which can act to degrade the performance of expensive vacuum equipment.  [c.241]

Through its committees, divisions, and chapters, the American Vacuum Society has produced a nearly complete bibhography (to 1996) (8), a dictionary of terms (9), a monograph series, and a number of other useful pubHcations (10). Another source of information is the Association of Vacuum Equipment Manufacturers. A history of vacuum ideas and technology development from the Middle Ages to Newton has been given (11).  [c.366]

Vacuum equipment requires strength to withstand the pressure of the surrounding atmosphere. The full load is ca 101.3 kPa when the internal gas pressure in the system is sufficiently reduced (see Pumps).  [c.378]

Vacuum Equipment The equipment shown in Fig. 10-105 has been discussed elsewhere in this section with the exception of the dif-  [c.935]

Glasses are used in enormous quantities the annual tonnage is not far below that of aluminium. As much as 80% of the surface area of a modern office block can be glass and glass is used in a load-bearing capacity in car windows, containers, diving bells and vacuum equipment. All important glasses are based on silica (SiOj). Two are of primary interest common window glass, and the temperature-resisting borosilicate glasses. Table 15.1 gives details.  [c.162]

Lubricating and seal oil systems cleaned Instrumentation and controls checked Preliminary operation of lubricating and seal oil systems Operation with air Vacuum Equipment Alignment run-in testing Pumps  [c.331]

Typical Capacities and Operating Ranges for Vacuum Equipment  [c.344]


WTien serving vacuum equipment, the temperatures are usually set as follows when the non-condensables do not exceed one percent of the total water vapor being condensed. See Figures 6-20 A, B, C, and D.  [c.375]

When the steam leaves a condensing turbine, it passes to a surface-type condenser for recovery of the condensate. Vacuum equipment (jets or pumps) are necessary to achieve high vacuums on the condenser.  [c.671]

Commercial equipment is available which automatically switches from atmospheric distillation to vacuum distillation and calculates the distillation curve as temperatures under atmospheric pressure conditions as a function of weight or volume per cent recovery.  [c.18]

The visbreaking process thermally cracks atmospheric or vacuum residues. Conversion is limited by specifications for marine or Industrial fuel-oil stability and by the formation of coke deposits in equipment such as heaters and exchangers.  [c.378]

The course of a surface reaction can in principle be followed directly with the use of various surface spectroscopic techniques plus equipment allowing the rapid transfer of the surface from reaction to high-vacuum conditions see Campbell [232]. More often, however, the experimental observables are the changes with time of the concentrations of reactants and products in the gas phase. The rate law in terms of surface concentrations might be called the true rate law and the one analogous to that for a homogeneous system. What is observed, however, is an apparent rate law giving the dependence of the rate on the various gas pressures. The true and the apparent rate laws can be related if one assumes that adsorption equilibrium is rapid compared to the surface reaction.  [c.724]

To prepare crystalline monoperphthalic acid, place the thoroughly dry ethereal solution (4) in a distilling flask equipped with a capillary tube connected with a calcium chloride or cotton wool drying tube, and attach the flask to a water pump. Evaporate the ether without the application of heat (ice will form on the flask) to a thin syrup (about 150 ml.). Transfer the syrup to an evaporating dish, rinse the flask with a little anhydrous ether, and add the rinsings to the syrup. Evaporate the remainder of the ether in a vacuum desiccator over concentrated sulphuric acid about 30 g. of monoperphthalic acid, m.p. 110° (decomp.), is obtained.  [c.810]

All biology labs and hospitals have autoclaves for sterilizing their equipment so if the chemist has access to one then all she needs to do is place the reactants in a flask, cover the flask with foil and blast them in an autoclave for a few hours. This, however, is probably not feasible so about the best thing Strike can think of for home use would be as follows. Still, Strike is not entirely sure if this apparatus is a correct one, and if the chemist also has some doubts then she would probably want to ask a professional research chemist who has used autoclaving as a synthetic tool. Strike s idea is to use a pipe bomb with a special fitting so that pressure from a pump can be introduced into the bomb. Most vacuum pumps are reversible so that they will produce pressure as well as vacuum. How much pressure Well, that is something the chemist is going to have to look up because it was not provided, and Strike does not want to look it up either. It is suffice to say that one is going to use as much pressure as is necessary to bring an ether solution to 120-130°C without it boiling.  [c.280]

Tracer Munitions. Tracer bullets guide the direction of the fire, aid in range estimation, mark target impact, and act as incendiaries. Tracers can, through preselected tracer colors, also serve for nighttime identification of the combatants. Red strontium-containing tracers are more visible under adverse atmospheric conditions, therefore these are preferred although green tracers based on barium salts also are used. Daylight visibitity can be enhanced by increa sing the fraction of magnesium in the tracer composition. With the increased use of night vision systems for pilots and ground artillery personnel, interest in tracers with reduced light output (dim tracers) has increased such devices are readily observable with night vision equipment but almost invisible to others. Conversely, the light output would not overwhelm night vision systems the way standard, high intensity tracer output can.  [c.351]

Vacuum systems, largely for the semiconductor industry, are the main source of sales (see Semiconductors). The sales of all vacuum equipment, pumps (qv), valves, sensors (qv), etc, in the United States, including apphcations not in vacuum systems, generally exceed 500 X 10 /yr. A reasonably comprehensive hst of high vacuum manufacturers is supphed by the American Vacuum Society s exhibitor s hst. In Europe, a special issue of the journal A acuum serves similady.  [c.379]

Infrared Optics. Although the standard wavelength of transmission used in siHca optical fiber networks is in the infrared (1.55 P-m), there are appHcations in which glasses transmitting to longer wavelengths are preferable. These include nose cones for heat-seeking missiles noninvasive monitoring of bodily fluids, eg, analysis of blood by transmitting ir radiation through an earlobe and lenses for night vision equipment. Some chalcogenide and haHde glasses transmit to the far-ir region (up to about 20 pm), but the relatively difficult preparation techniques and the relatively poor chemical, thermal, and mechanical properties of these glasses can compHcate use. For example, some commercially available chalcogenide glasses must be sealed with a polymer coating to prevent slow reaction with air and water vapor.  [c.335]

Conductance equations for several other geometries are given by Ryans and Roper (Process Vacuum System Design and Operation, chap. 2, McGraw-Hill, New York, 1986). For a circular annulus of outer and inner diameters Di and Do and length L, the method of Guthrie and Wakerling (Vacuum Equipment and Techniques, McGraw-HiU, New York, 1949) may be written  [c.641]

FIG. 18-75 Eqi lipment prices, FOB point of fabrication, for typical crystallizer systems. Prices are for crystallizer plus accessories including vacuum equipment. (Data supplied hy Swenson Process Equipment, Inc., effective Januaiy, 1.9.95.)  [c.1672]

Glass can support large static loads for long times. Aircraft windows support a pressure difference of up to 1 atmosphere. Windows of tall buildings support wind loads diving bells have windows which support large water pressures glass vacuum equipment carries stress due to the pressure differences at which it operates. In Cambridge (UK) there is a cake shop with glass shelves, simply supported at both ends, which on weekdays are so loaded with cakes that the centre deflects by some centimetres. The owners (the Misses Fitzbillies) say that they have loaded them like this, without mishap, for decades. But what about cake-induced slow crack growth In this case study, we analyse safe design with glass under load.  [c.190]

A vacuum condenser has vacuum equipment (such as steam jets) pulling the noncondensibles out of the cold end of the unit. A system handling flammable substances has a control valve between the condenser and Jets (an air bleed is used to control nonflammable systems). The control method involves derating part of the tube surface by blajiketing it with noncondensibles that exhibit poor  [c.291]

Unlike traditional surface science techniques (e.g., XPS, AES, and SIMS), EXAFS experiments do not routinely require ultrahigh vacuum equipment or electron- and ion-beam sources. Ultrahigh vacuum treatments and particle bombardment may alter the properties of the material under investigation. This is particularly important for accurate valence state determinations of transition metal elements that are susceptible to electron- and ion-beam reactions. Nevertheless, it is always more convenient to conduct experiments in one s own laboratory than at a Synchrotron radiation focility, which is therefore a significant drawback to the EXAFS technique. These focilities seldom provide timely access to beam lines for experimentation of a proprietary nature, and the logistical problems can be overwhelming.  [c.224]

Additional information on vacuum technology and its application to drying can be obtained from the American Vacuum Society. The American Vacuum Society (AVS) is a nonprofit organization which promotes communication, dissemination of knowledge, recommended practices, research, and education in the use of vacuum and other controlled environments to develop new materials, process technology, devices, and related understanding of material properties. The AVS is comprised of 8 technical divisions, 4 technical groups, 20 local-area chapters and about 6000 members worldwide. The Society provides stimulating symposia, short courses, and educational outreach both at the national and local levels. The AVS Headquarters is located at 120 Wall Street, 32nd Floor, New York, NY 10005.Phone 212-248-0200 Fax 212-248-0245. Also, the following is a partial list of vacuum equipment and material suppliers which may be contacted for further information  [c.149]

Figure 6-9A. Where vacuum equipment appiies. By permission, ingersoll-Rand Co. Figure 6-9A. Where vacuum equipment appiies. By permission, ingersoll-Rand Co.
The importance of low pressures has already been stressed as a criterion for surface science studies. However, it is also a limitation because real-world phenomena do not occur in a controlled vacuum. Instead, they occur at atmospheric pressures or higher, often at elevated temperatures, and in conditions of humidity or even contamination. Hence, a major tlmist in surface science has been to modify existmg techniques and equipment to pemiit detailed surface analysis under conditions that are less than ideal. The scamiing tunnelling microscope (STM) is a recent addition to the surface science arsenal and has the capability of providing atomic-scale infomiation at ambient pressures and elevated temperatures. Incredible insight into the nature of surface reactions has been achieved by means of the STM and other in situ teclmiques.  [c.921]

The fact that electron beam instmments work under high vacuum prohibits the analysis of aqueous systems, such as biological materials or suspensions, or emulsions without specimen preparation as outlined above. These preparation procedures are time consuming and are often not justified in view of the only moderate resolution required to solve a specific practical question (e.g. to analyse the grain size of powders, bacterial colonies on agar plates, to study the solidification of concrete, etc). Enviromnental SEM (ESEM) and high-pressure SEM instmments are equipped with differentially pumped vacuum systems and Peltier-cooled specimen stages, which allow wet samples to be observed at pressures up to 5000 Pa [48]. Evaporation of water from the specimen or condensation of water onto the specimen can thus be efficiently controlled. No metal coating or other preparative steps are needed to control charging of the specimen since the interaction of the electron beam with the gas molecules in the specimen chamber produces positive ions that can compensate surface charges. High-pressure SEM , tlierefore, can study insulators without applymg a conductive coating. The high gas pressure in the vicinity of the specimen leads to a squirting of the electron beam. Thus the resolution-limiting spot size achievable on the specimen surface depends on the acceleration voltage, the gas pressure, the scattering cross section of the gas and the distance the electrons have to travel tlirough tlie high gas pressure zone [49]. High-pressure SEM and ESEM is still under development and the scope of applications is expanding. Results to date consist mainly of analytical and low-resolution images (e.g. [ ]).  [c.1642]

It has long been the goal of many catalytic scientists to be able to study catalysts on a molecular level under reaction conditions. Since the vast majority of catalytic reactions take place at elevated temperatures, the use of STM for such in situ catalyst investigations was predicated upon the development of a suitable STM reaction cell with a heating stage. This has now been done [3] by McIntyre et al, whose cell-equipped STM can image at temperatures up to 150 °C and in pressures ranging from ultraliigh vacuum up to several atmospheres. The set-up has been used for a number of interesting studies. In one mode of operation [63] (figure B 1.19.13(a)), a Pt-Rli tip was first used to image clusters of carbonaceous species fonned on a clean Pt(l 11) surface by heating a propylene adlayer to 550 K, and later to catalyze  [c.1687]

Veratraldehyde (methyl vanillin). Place 152 g. of a good sample of commercial vanillin, m.p. 81-82°, in a 1 litre three-necked flask (or Pyrex wide-mouthed bottle), equipped with a reflux condenser, a mechanical stirrer, and two separatory funnels (one of these may be supported in the top of the reflux condenser by means of a grooved cork). Melt the vanillin by warming on a water bath and stir vigorously. Charge one funnel with a solution of 82 g. of pure potassium hydroxide in 120 ml. of water and the other funnel with 160 g. (120 ml.) of purified dimethyl sulphate (1) CAUTION conduet all operations with dimethyl sulphate in the fume cupboard). Run in the potassium hydroxide solution at the rate of two drops a second, and 20 seconds after this has started add the dimethyl sulphate at the same rate. Stop the external heating after a few minutes the mixture continues to reflux gently from the heat of the reaction. The reaction mixture should be pale reddish-brown since this colour indicates that it is alkaline should the colour change to greeu, an acid reaction is indicated and this condition should be corrected by shghtly increasing the rate of addition of the alkali. When half to three-quarters of the reagents have been added, the reaction mixture becomes turbid and separates into two layers. As soon as all the reagents have been run in (about 20 minutes), pour the yellow reaction mixture into a large porcelain basin and allow to cool without disturbance, preferably overnight. Filter the hard crystalline mass of veratraldehyde, grind it in a glass mortar with 300 ml. of ice cold water, filter at the pump and dry in a vacuum desiccator. The yield of veratraldehyde, m.p. 43-44°, is 160 g. This product is suflSciently pure for most purposes it can be purified without appreciable loss by distillation under reduced pressure, b.p. 158°/8 mm. m.p. 46°. The aldehyde is easily oxidised in the air and should therefore be kept in a tightly stoppered bottle.  [c.804]

Scientists at Los Alamos have produced a tantalum carbide graphite composite material, which is said to be one of the hardest materials ever made. The compound has a melting point of 3738oC. Tantalum is used to make electrolytic capacitors and vacuum furnace parts, which account for about 60% of its use. The metal is also widely used to fabricate chemical process equipment, nuclear reactors, aircraft, and missile parts. Tantalum is completely immune to body liquids and is a nonirritating material. It has, therefore, found wide use in making surgical appliances. Tantalum oxide is used to make special glass with high index of refraction for camera lenses. The metal has many other uses.  [c.133]

A solution of lithium propynethiolate was prepared on a 0.10 molar scale as described in Exps. 46, 47. The brown solution was transferred into the dropping funnel and was added during 40 min to a mixture of 0.10 mol of methyl methane-thiosulfonate and 50 ml of dry diethyl ether. During this addition the temperature was maintained between -40 and -45°C. After removing the cooling bath the temperature was allowed to rise to -10°C. The reaction mixture was poured into ice-water and, after shaking, the layers were separated. The aqueous layer was extracted twice with diethyl ether. After drying the combined solutions, the diethyl ether and hexane were removed completely in a water-pump vacuum, keeping the bath temperature below 25°C (note 1). The flask was then equipped for a distillation in a high vacuum (pressure lower than 0.2 mmHg). When the pressure had dropped below 0.5 mmHg, the (single) receiver was immersed in a bath at -50°C. The distillation flask was completely immersed in a bath at 25-30°C. The contents  [c.69]

The two extracts were combined and washed six times with 2 N HCl. The light petroleum solutions were dried over magnesium sulfate, then poured into a 1-1 round-bottomed flask, which was equipped for vacuum distillation with a 40-cm Vigreux column, condenser and receiver, cooled at -75°C (see Fig. 5). A tube filled with KOH pellets was placed between the receiver and the water pump. The apparatus was evacuated (10-20 mmHg) and the flask was gradually heated until the light petroleum began to pass over. The distillate was heated under reflux under nitrogen for 20 min (note 2), and was subsequently distilled in a partial vacuum. CH3C C-CH2CeCH, b.p. aa. 55°C/100 mmHg, n 1.4474, was obtained in 74"7 yield.  [c.72]

In the flask were placed 40 g of dry, pure HMPT (note 1) and 3 g of finely powdered KO-tert.-C Hj (see Exp. 4, note 2). The mixture was warmed at 50-60°C and after all of the solid material had passed into solution 7.5 g of terf.-butyl-alcohol and 9.5 g of ethynylcyclohexene (for the preparation of this compound see ref. 165) were added successively. The temperature of the mixture was adjusted to 55 C directly after these additions, and was kept for 10 min between 54 and 56°C (note 2) by occasional cooling or heating. The brown mixture was then poured into 200 ml of ice-water and five extractions with very small portions of redistilled pentane were carried out. The pentane extracts (total volume about 130 ml) were washed three times with water and subsequently dried over magnesium sulfate. The pentane solution was transferred into a 250-ml round-bottomed flask, which was equipped for distillation in a water-pump vacuum, using the apparatus of Chapter I, Fig. 5. The receiver was immersed in a bath at Q°C and the pentane was removed in a water-pump vacuum. The temperature of the heating bath was increased gradually. The allenic compound distilled between 35 and 40°C/17 mmHg  [c.91]

The flask was then equipped for distillation by means of an oil pump, using a pressure of 1 ramHg or lower. The volatile product was collected in a single receiver, cooled at -75°C. The contents of the receiver were washed three times with ice-water in a small separating funnel (50-100 ml) and subsequently dried over magnesium sulfate (just enough to cause disappearance of the turbidity). The liquid was then distilled in a water-pump vacuum using a 20-cm Vigreux column and a single receiver, cooled in ice (note 2). The allenic ether (b.p. 20-25°C/15 mmHg, n 1.4906) was obtained in 83% yield. The compound dimerizes (or polymerizes) rapidly at room temperature, and should be stored at -Bo C.  [c.97]

See pages that mention the term Vacuum equipment : [c.867]    [c.880]    [c.168]    [c.69]    [c.380]    [c.8]    [c.352]    [c.368]    [c.369]    [c.912]    [c.430]    [c.56]    [c.69]   
Applied Process Design for Chemical and Petrochemical Plants, Volume 1 (1999) -- [ c.343 ]