Particular Piece Of Equipment Research Articles

Simulation of thermal desalination processes

Different flow sheets for thermal desalination processes were simulated using the computer program Evapolund. This general software is modular in structure and includes a number of modules describing different components in an evaporation process such as evaporators, different types of heat exchangers, condensers, flash drums, compressors, steam jet ejectors, etc. The program includes a comprehensive database for the physical properties of seawater as well as other liquors, and a library containing correlations for the heat transfer coefficient of different heat transfer surfaces and flow regimes. Designed to be very flexible, the program can be used as an excellent tool for the design and evaluation of all types of thermal desalination processes. Account is made to different thermodynamic losses in the process such as boiling point elevation, non-equilibrium allowance inside the evaporators and flashing drums, temperature drops due to pressure drops in demisters, transmission lines, and condensers. The user can easily construct the flow sheet of the process and provide a minimum of input data, depending on the calculation case at hand. Simulation results can be displayed either graphically, or converted as a text file, or in any other form chosen by the user and can be studied either for the whole plant such as temperature, pressure and concentration profiles, or for a particular piece of equipment in the plant. The paper gives simulation results of four thermal desalination processes to demonstrate the capabilities of the program.

Conductivity Sensors for the Mineral Processing Industry

There are many examples in mineral processing where the operation of a particular piece of equipment cannot be optimized because some of the most important variables are poorly sensed. These cases include dispersions of gases and/or solids in water with concentrations that rapidly change in time and space. The electrical conductivity of dispersions in a conducting liquid is a strong function of the concentration of the dispersed phase(s). Models relating the conductivity of the dispersion to gas holdup or solids content have been available for many years. These models have proven to be accurate for a wide range of situations and conditions including those pertinent to mineral processing. The use of conductivity in some of these situations seems attractive because of its intensive nature, its fast response time, and the fact that it can be directly used to calculate the content of the dispersed phase with no calibration. However, a major difficulty is the development of conductivity cells compatible with p...

Structural features of steels strengthened by thermoplastic working

1. The strengthening of thermoplastically worked steels is caused by grain refinement probably related to structural changes which are specific for each class of steels. 2. The structure of steels strengthened by thermoplastic working is determined not only by the chemical composition and geometry of the blanks and deformation conditions but also by the design of the specific piece of equipment, upon which depend the level and rate of deformation and the time of relaxation processes.

Refractories for vacuum degassing of steel

New equipment for outside-the-furnace vacuum degassing of steel includes argon-oxygen refining units, circulation flow vacuum degassing units, and units for steel degassing in the ladle with electric arc heating. The refractories developed for use in this equipment include magnesia, periclase-carbon, corundum, alumina, periclase-lime, magnesia-dolomite, forsterite, and unformed and vibrocompacted refractories. The refractories were selected for heat resisting and thermal insulation applications. This paper reviews at length the raw material base, production processes, and applicable properties of these refractories under degassing conditions, including slag and silicate resistance, temperature and phase behavior, permeability, compression strength, service life, and wear behavior. In addition, specifications are given for a wide range of refractories and their applications in specific pieces of equipment. Savings in refractory and power consumption are discussed.

Quantitative effects of electrical and vibrational stresses on reliability

AbstractThis article presents some details on how electrical and vibrational stresses exacerbate failures. This is one of a series of articles on similar subjects by this author. One electrical defect type is pin‐holes in oxide layers in ICs. Electrical leakage current through a low insulation pin‐hole could cause temperature rise and ultimately, when electrons of sufficient energy causing an avalanche, a thermal runaway condition could develop and maintain an electrical short. On the other hand electromigration could cause conductor opens. Aircraft data indicated that vibration related failures constituted more than 14 per cent of the total number of field failures. Fatigue failures can be directly related to S/N curves of stress to number of cycles to failure. Some measurements indicated that for a particular piece of equipment tested the time to failure varied inversely as the fourth power of vibrational acceleration; and failures of specific groups of component part types were sensitive to particular vibrational acceleration levels. Much information exists that gives quantitative measures on how stresses exacerbate failures. However, there is still a big gap in the relationship between the engineering fundamentals and the failures experienced. The author urges the readers to join force to develop a new reliability engineering foundation based on relationships of defects, failure mechanisms and stresses from which future reliability predictions and reliability analyses can be conducted.

A Dynamic Programming Approach to Equipment Loss Analysis

Frequently, managers concern themselves with the problem of when to replace a piece of equipment. Assuming adequate funds, replacement normally occurs when the item is worn out or when the cost of replacement is less than the increased economic value that will occur because of replacement. Unfortunately, this approach overlooks the problem faced by a firm's risk manager. The risk manager is concerned with the loss exposure that emanates from a particular piece of equipment. As an example, consider a boiler located in a manufacturing plant. A boiler can pose many problems from the perspective of the risk manager. Explosion of the boiler could result in damage to the boiler and probably to the boiler's physical environment. Profits may be lost because of a business interruption. Bodily injury and property damage actions in tort may arise. All of these types of potential losses play an important part in the risk manager's decision-making process. A risk manager might prefer to remove a piece of old equipment because of loss potential while a financial officer charged with the purchase of equipment may be unwilling to replace equipment that still has substantial economic value. This paper suggests the use of dynamic programming as an aid to the risk manager in equipment replacement decisions. The objective of the risk manager is to minimize potential losses, whereas the financial officer is typically concerned with maximizing profits. The systems viewpoint suggests that the concerns of the risk manager along with those of the financial officer should be considered in many decisions. However, all too often the risk manager does not have input into decisions in which his concerns should be recognized. The dynamic programming technique provides a program to minimize potential losses, and, in cases in which the suggested program differs from that of the financial manager, it can be used to emphasize the need to consider input from the risk manager.

Noise control techniques for existing power plants

This paper provides guidelines for the selection and application of appropriate noise control techniques for equipment located in existing power plants. Several noise reduction techniques, the scientific principles involved, and the major devices utilized with each technique are listed and discussed. Possible sources of power plant noise are identified and possible methods of noise reduction are given. The selection of the most appropriate method for a particular piece of equipment can only be determined by an engineering analysis of each noise problem with careful consideration given to the economic feasibility as well as the effects on operation and maintenance of the equipment involved.

Comparison of fatigue effects in simulated and actual earthquakes

One of the unresolved aspects of simulated earthquake testing concerns the amount of low-cycle fatigue produced by a series of single-frequency-vibration tests compared to random-motion excitation. The recommended sinebeat vibration input using 5 cyc/beat at each measured equipment natural frequency is considered conservative because it can produce more fatigue damage than the most severe earthquake being postulated. A computer-aided analysis has been made of simple mass-spring-damper systems representing the uncoupled structure and equipment response to well-known acceleration-time histories available for both the El Centro-1940 and San Fernando-1971 earthquakes. In the proposed testmachine simulation, the comparable sine-beat-vibration input was adjusted to duplicate the building-floor response at the base of the equipment, which was represented as a series of oscillators geometrically spaced in the 1 to 25-Hz range of damaging earthquake effects. Both large- and small-strain ranges have been compared, but these values are assumed for convenience and cannot be used as actual seismic effects in specific pieces of equipment.

Clinical and Administrative Judgment

Most nursing practitioners of my own vintage have, unfortunately, been taught to judge alternatives dualistically-as right or wrong, good or bad, correct or incorrect. Sometimes such simplistic dualism is appropriate. For example, it is right, good, and correct to observe welldefined rules of aseptic technique in changing a dressing; it is wrong, bad, and incorrect to contaminate a wound dressing. Many clinical decisions, such as those concerned with use of a particular piece of equipment in a particular patient's care, however, cannot be based on such simplistic, dualistic precepts.

Auxiliary and Ancillary Equipment

THE evolution and basic design philosophy, aerodynamic design, structural design, power plant, systems, interior arrangements, flying controls and automatic landing, reliability, quality control and maintenance of the Short Brothers and Harland Belfast C. Mk. 1 strategic freighter have been dealt with in considerable detail in the preceding eight articles. The object of this final article is to provide further ‘backup’ information especially on the systems side but whereas the earlier articles have dealt with overall systems and philosophies, it is intended here to describe specific pieces of equipment and the contributions made by a number of Companies within the industry to the Belfast programme.

Auxiliary and Ancillary Equipment

THE operating economics, basic design philosophy, power plants, and systems, structural and aerodynamic design of the British Aircraft Corporation One‐Eleven short‐range airliner have been dealt with in considerable detail in the preceding five articles. This final article is intended as ‘back‐up’ information—primarily to the systems description by Mr Carline—but whereas the earlier descriptions have concentrated upon general philosophies and the complete systems, it is intended here to describe specific pieces of equipment and the contributions of a number of Companies in support of the BAC One‐Eleven programme.

The Feasibility of Economic Leasing in the Oil Industry - An Equipment Analysis

Abstract This paper presents a complete analysis of the economics of leasing equipment by the petroleum producer. Using the basic premise that capital which is freed by leasing equipment rather than purchasing outright can be put to more productive use, graphs are presented to illustrate economic conditions which occur when the operator leases equipment. Both the major producer who might have large amounts of capital readily available and the smaller one with limited funds may be financially aided by equipment leasing. In the first case, the capital freed by leasing production equipment can be used more productively to discover or develop additional reserves, rather than as the advance payment for the future use of a capital asset. Secondly, since equipment leasing extends virtually 100 per cent financing to both, the small independent has the use of needed equipment without the over-extension of bank credit or the possible dilution of equity which can occur when outside financing is required. Long-term sale and lease-back of plant or producing facilities offers another method for the oil producer to acquire additional funds for development work. Under this plan it is possible for the producer to sell full or partially depreciated equipment to the leasing company and immediately lease it back. Any capital loss or gain which is realized can be effectively utilized by the producer. Introduction Still prevalent today is the concept that pride of ownership of fixed assets is justifiable even when cost considerations might suggest equipment leasing. This is a survival of the notion that buying all the future services of a given property at once is a more natural procedure than buying such services as needed. Today, the process of obtaining the use of capital assets by lease rather than purchase is gaining acceptance in many phases of United States business, but it is still relatively unknown in the petroleum industry. Lease financing or leasing of equipment has had a tremendous growth since the early 1950's not only in volume, but also in the types of equipment which can be leased. One company recently announced a "new milestone in American business finance", which turned out to be a program under which qualified applicants can lease money. This announcement pointed out the major advantage which the program offered over conventional equipment leasing-that the lessee was not restricted to a specific piece of equipment but could purchase any items he desired with the "leased" money. The equipment-leasing industry began to come into its own in 1952 and has had a substantial growth since that time. The dollar volume of equipment on lease, excluding transportation equipment and business machines, has grown from $40 million in 1954 to $500 million in 1960, as shown in Fig. 1. The industry estimates that it should exceed $1 billion by 1965. Approximately $330 million of the 1960 business was handled directly by equipment manufacturersThe remaining $200 million represents the contribution of the leasing companies who do no manufacturing themselves but who buy the equipment from manufacturers for lease to customers. JPT P. 355^

Reliability analysis for aircraft generators

MUCH HAS BEEN WRITTEN on the subject of reliability, but there still exists a need for industry-wide agreement on a precise definition of the meaning of the numerical value of reliability associated with specific pieces of equipment.

Protective finishing of electrical equipment

This paper is a review of current practice and methods of protective finishing for electrical equipment. It covers most conditions met in normal service, but excludes the more specialized tropical and arctic conditions, which differ considerably from normal applications. The conditions under which the protective finishes are used are divided into six classes, and the service conditions for each class are described. Different types and methods of protective finishing are reviewed and described in some detail, together with reference to a number of self-protective materials. The choice of a finish for a particular piece of equipment is frequently a compromise between the various factors involved, but a broad tabulation is given with examples of the influence of particular factors in a final choice. The correct evaluation of accelerated tests on finishes is most difficult, and the necessity for correlation with field experience is stressed. Methods of testing and process control are reviewed and some of the difficulties which arise in service are illustrated. This review of the field of protective finishes shows the range of problems which must be considered by the engineer when designing and manufacturing his products, and points to the desirability of close co-operation with the industrial chemist.