Search

We report measurements of Υ meson production in p + p, d + Au, and Au+Au collisions using the STAR detector at RHIC. We compare the Υ yield to the measured cross section in p + p collisions in order to quantify any modifications of the yield in cold nuclear matter using d + Au data and in hot nuclear matter using Au+Au data separated into three centrality classes. Our p + p measurement is based on three times the statistics of our previous result. We obtain a nuclear modification factor for Upsilon (1S + 2S + 3S) in the rapidity range |y| < 1 in d + Au collisions of RdAu = 0.79 ± 0.24(stat.) ± 0.03(syst.) ± 0.10(p + p syst.). A comparison with models including shadowing and initial state parton energy loss indicates the presence of additional cold-nuclear matter suppression. Similarly, in the top 10% most-central Au + Au collisions, we measure a nuclear modification factor of R AA = 0.49 ±0.1(stat.) ±0.02(syst.) ±0.06(p + p syst.), which is a larger suppression factor than that seen in cold nuclear matter. Our results are consistent with complete suppression of excited-state Upsilon mesons in Au + Au collisions. Themore » additional suppression in Au + Au is consistent with the level expected in model calculations that include the presence of a hot, deconfined Quark–Gluon Plasma. However, understanding the suppression seen in d + Au is still needed before any definitive statements about the nature of the suppression in Au + Au can be made.« less

We report measurements of Upsilon meson production in p + p, d + Au, and Au + Au collisions using the STAR detector at RHIC. We compare the Upsilon yield to the measured cross section in p + p collisions in order to quantify any modifications of the yield in cold nuclear matter using d + Au data and in hot nuclear matter using Au + Au data separated into three centrality classes. Our p + p measurement is based on three times the statistics of our previous result. We obtain a nuclear modification factor for Upsilon (1S + 2S + 3S) in the rapidity range vertical bar y vertical bar < 1 in d + Au collisions of R-dAu = 0.79 +/- 0.24(stat.) +/- 0.03(syst.) +/- 0.10(p + p syst.). A comparison with models including shadowing and initial state parton energy loss indicates the presence of additional cold-nuclear matter suppression. Similarly, in the top 10% most-central Au + Au collisions, we measure a nuclear modification factor of R-AA = 0.49 +/- 0.1(stat.) +/- 0.02(syst.) +/- 0.06(p + p syst.), which is a larger suppression factor than that seen in cold nuclear matter. Our results are consistent with complete suppression of excited-state Upsilon mesons in Au + Au collisions. The additional suppression in Au + Au is consistent with the level expected in model calculations that include the presence of a hot, deconfined Quark-Gluon Plasma. However, understanding the suppression seen in d + Au is still needed before any definitive statements about the nature of the suppression in Au + Au can be made. (C) 2014 The Authors. Published by Elsevier B.V.

We report J / ψ spectra for transverse momenta p T > 5 GeV / c at mid-rapidity in p + p and Au + Au collisions at s NN = 200 GeV . The inclusive J / ψ spectrum and the extracted B-hadron feed-down are compared to models incorporating different production mechanisms. We observe significant suppression of the J / ψ yields for p T > 5 GeV / c in 0–30% central Au + Au collisions relative to the p + p yield scaled by the number of binary nucleon–nucleon collisions in Au + Au collisions. In 30–60% mid-central collisions, no such suppression is observed. The level of suppression is consistently less than that of high- p T π ± and low- p T J / ψ at RHIC and high- p T J / ψ at the LHC.

We report a high precision measurement of the transverse single spin asymmetry A(N) at the center of mass energy root s = 200 GeV in elastic proton-proton scattering by the STAR experiment at RHIC. The A(N) was measured in the four-momentum transfer squared t range 0.003

These experiments examined the relationship between behavioral and electrophysiologic signs of neuromuscular dysfunction in rats with zinc pyridinethione (ZPT)-induced neurotoxicity. ZPT added to the diet of adult rats at 50 ppm produced a moderate (approximately 200 g) reduction in forelimb and hindlimb grip strength which occurred during the second week of dosing. Other behavioral tests of peripheral nervous system toxicity were affected inconsistently. Electrophysiologic changes included a marked (maximum 95%) reduction of indirect muscle-evoked potential (M-wave) and a decrement (maximum 30%) during repetitive M-wave elicitation. Electrophysiologic changes were greater in hindlimb than in forelimb. Needle electromyography revealed denervation potentials in ZPT-treated rats which appeared after M-wave changes and recovered faster than did M-wave amplitude. Caudal nerve conduction velocity was unaffected, indicating that peripheral neurotoxic effects were confined to the neuromuscular junction. When ZPT exposure was discontinued, grip strength recovered in about 1 week. In contrast, electrophysiologic measures required 42 days to recover completely. These results indicate that deficits in neuromuscular junction physiology are a sensitive index of ZPT-related distal axonopathy.

The response to ammonia of silicon-based Metal Oxide Semiconductor Field Effect Transistor (MOSFET) devices having either evaporated or sputtered Pt gate electrodes has been studied. A substantial difference in ammonia sensitivity was observed between these two types of device, which is thought to be related to differences in morphology between the two types of gate electrode; devices having evaporated Pt gate electrodes, which are non-continuous, are very ammonia sensitive, whereas devices having sputtered Pt gates, which are continuous, are not ammonia sensitive. However, both the evaporated and sputtered gate devices exhibit a similar response to hydrogen (typically, changes in threshold voltage (VT) of approximately -420 mV and -350 mV respectively to 500 ppm hydrogen at 150 °C). The ammonia sensitivity of the evaporated Pt-gate MOSFET is dependent on both temperature and ageing effects; the optimum operating temperature of this device is 175 °C, and a burn-in period of approximately 48 h at 200 °C is necessary before the maximum response to ammonia is observed. The humidity response of both evaporated and sputtered Pt-gate MOSFET devices has been studied at 175 °C; a change from 20 to 95% r.h. does not produce a significant response from either of these devices (ΔVT is typically -35 mV and -5 mV respectively).

Forty adult patients (average age 40 years), with the clinical and radiological features of the Chiari malformations, were seen at the Toronto Western Hospital between 1967 and 1984. Surgical confirmation of the diagnosis was obtained in 32 cases; of these, 23 were classified as Chiari I malformation while 9 fulfilled the anatomic criteria of Chiari II. The patient population consisted of 22 males and 18 females. Common presenting symptoms included head and neck pain (60%), sensory complaints (60%), upper extremity weakness (42%), and gait disturbance (40%). Neurological findings included signs of central cord dysfunction (73%), long-tract motor and/or sensory findings (58%), brainstem signs (38%), cerebellar dysfunction (18%), and increased intracranial pressure (15%). The majority of patients underwent myelography with or without computed tomography of the cervical-medullary junction. Two recent patients had 0.15T MRI scans which helped demonstrate an intramedullary syrinx. Thirty-three patients underwent 47 operative procedures (discounting spinal fusion and CSF shunt revisions). Open surgical management was performed in 32 patients, with CSF shunting along in one patient. Five patients (15%) incurred surgical complications within a six week postoperative period. Follow-up to date, ranges from one month to 11 years. In the 33 surgically treated patients, 18 are improved (55%), 10 are neurologically stable (30%), and five have worsened clinically (15%), including one death. Based on this study it appears that the Chiari II malformation maybe more common in adults than previously recognized. Surgical intervention has a favourable outcome in the majority of patients but a significant proportion continue to deteriorate.

We report on a polarization measurement of inclusive J/ψ mesons in the di-electron decay channel at mid-rapidity at 2

Publisher Summary The chapter discusses the completion of any radio installation project by a group till the programmed date successfully. All activities in the initial stages need to have been properly programmed and completed. This calls for a close monitoring and reporting system, particularly during the period of collaboration between these two groups. Computer print-outs, on project progress, and expenditure for control purposes are important requirements for large engineering projects. A period of two months has been found to be a reasonable period for projects to complete. On any project, it is possible that the critical path would change if the circumstances have a serious impact on the project. Although the critical path through a project is fairly constant, all contracts not on the critical path should be programmed in detail because many have little slack and require careful supervision. All project engineers should be provided with simplified print-outs and should be given clear guidance on the significance and operation of networks and print-outs. Network programs should be formulated by staff experienced in radioengineering and the requirements of the project for which the programme is produced. It is important to monitor all the activities in the project master program and all the individual contract activities.

This chapter discusses the detection and fire protection facilities for a radio station. Fire protection facilities, such as automatic alarms, sprinkler systems, fire hydrants, and other such permanent facilities required for a radio station, should be installed as a part of the initial engineering services of the building. A wide range of devices are available for the detection of fire, and the type of unit to be installed in a particular location should be determined only after careful consideration of the nature of the fire that would most likely occur in the immediate area. Modern devices are sensitive in nature and it is important that station staff is reminded of this fact, particularly when working with soldering irons, close to the unit. Care should be taken to ensure that the detector is installed clear of obstructions to air flow, and in an area of maximum effectiveness.

This chapter discusses the methods and procedures that are related to maintenance of masts and tower. Methods and procedures for doing structural work must be developed with safety in mind for masts and tower. The riggers and radio linesmen doing the work should be equipped with the best devices, equipment, and tools available. They should have good safety equipment such as cages, lifts, work boxes, safety chains, and belts, which are inspected and tested on a regular routine basis to ensure that they are in first class condition. One type of maintenance platform utilizes short sections of extension ladders or telescoping scaffolding frames to raise a work platform to the desired height. Designs for safety belts are available that permit the wearer to move freely but limit a fall without undue shock. Belts become dirty particularly after work on creosoted transmission line or antenna support poles. Regular cleaning is advantageous but care must be taken to ensure that phenol compounds, strong acids, and alkalis are avoided. Where a structure is used as a radiator for medium frequency broadcasting, mechanical failure can occur as a result of the effect of the applied working voltage.

This chapter focuses on the performance of materials and equipment used in radio installations. Several kinds of radio and electronic equipment are constructed of many different materials, each of which might suffer deterioration in different ways. The physical properties of plastics depend more on environmental operating temperature than those of metals. The variety of plastic materials and detailed accurate information available about them are such that the designer can choose a material for a certain application with a high degree of certainty that he would be able to obtain such characteristics. Plastic covered cables buried in the ground are soon damaged by termites and brown ants where these insects are prevalent. High claims are made on performance and life of modern contacts but environmental conditions can introduce many problems. Impurities in the air can cause a lot of troubles. Then there are chemical combinations that produce thin films on the contact surfaces. These films have to be cracked by the contact pressure and removed by the sliding motion of the contacts. Silver is also used in radio equipment because of its high conductivity but silver migration can be a problem in environments of high humidity. In certain conditions, the use of silver leads to the development of low insulation resistance or even complete breakdown of an insulating gap.

Publisher Summary This chapter discusses the concept of capital cost. Capital cost is the first or initial cost and is incurred before the service it provides, becomes available. It includes the cost of materials, labor, incidentals, contractor's bills—if any part of the work is carried out under contract—and associated engineering administrative charges. It also includes cash or short term investments, which might be maintained to pay for new work and to meet current expenses in advance of receipt of revenues from equipment or plant. The type of estimate prepared for the determination of the first or initial capital cost of a project in connection with an economic comparison study is the preliminary type as distinct from the approximate and the detailed estimates. Two main factors associated with estimating are costs of material and labor.

Publisher Summary This chapter discusses the importance of trend analysis in radio engineering projects. Trend analysis is defined as the provision of information in advance of a threatened crisis to enable the management to take effective action to forestall and mitigate the effects of that crisis. Most control systems data tend to be processed on a historical basis, that is, after the event has occurred. The ideal is real time control where each event is fed into the system and combined with all the other information existing in the system and its effects determined so that the cumulative effects and trends might be worked out. The best known and simplest evaluation of trend is the moving annual trend and it finds important application in the control of operations and maintenance expenditures of radio establishments. The moving annual trend is made up by taking the results of expenditure at the close of the last financial year and at the end of the following month, adding the results for the new month, and subtracting the results for the corresponding month of the old year. In rate of expenditure, the expenditure is plotted cumulatively against time whereas the total cost of a project is made up of two kinds of expenditure, direct costs, and indirect costs.

Publisher Summary This chapter discusses the concept of best form of organization, one that furnishes the most effective and direct means for the operation of management. To achieve the best, good management and organization are vital. The form of organization should have the capacity to endure and develop. The form of organization should provide for coordination so that the work of each group is scientifically related to that of others, that overlapping and unallotted areas are avoided and the whole is employing its energies for a single purpose. Each individual should be provided with a clear set of duties and an unqualified responsibility for their execution. The form of organization should also provide for the allocation of duties according to the normal capacity of the individual. The organizational structure should be such that no one is required to report to more than one line supervisor. Every member should know to whom he reports and who reports to him.

This chapter focuses on the safety aids and facilities available at radio stations. A supply of first aid equipment, protective clothing, safety aids, fire extinguishing plant and equipment sufficient to enable employees to meet the requirements of the safety rules should be provided on every station. First aid and fire extinguishing equipment should be provided in conspicuous and suitable places throughout the station buildings, near line matrix switching equipment, coupling huts, power house, line material storage depots, and also in vehicles used for construction work or the transport of staff. The nature and extent of medical attention provided, and the first aid facilities, must be sufficient for the needs of the employees, having regard to the hazardous nature of the work at the station, and the distance from hospital or other medical assistance. All exits and thoroughfares should be instantly recognizable not only by those personnel working on the station but by the visitors to the station and others. No person should be allowed to work alone on a transmitter or any other radio or electrical equipment, or carry out testing or experimental work on such equipments.

Publisher Summary This chapter focuses on the retirement of a particular equipment or plant in radio stations. There are several reasons for withdrawal of equipment or plant including the installed equipment or plant has failed in service and would no longer function; the equipment or plant does not have sufficient capacity to meet current needs; the equipment might be obsolete because of the changes in conditions or service that it must render; more efficient equipment or plant that would operate at lower cost is available or some new method of providing service are available. The retirement cost is the estimated cost of recovery of equipment or plant, net of any residual value remaining at the end of its estimated life. The retirement cost might be a negative value if the residual or scrap value of the equipment is estimated to be higher than the costs of removal and disposal. An unusual retirement situation occurs when it becomes necessary to dismantle the towers that have been erected on buildings or in other such difficult situations.

Publisher Summary This chapter discuss about the requirement of project control in radio stations. It necessitates the provision of a facility for reviewing the project master program. The extent of the control exercised on a project would depend on its magnitude, complexity, cost, and importance. Objectives must be set for every project whether design, installation, or operation types. The next step is the allocation of resources. Monitoring of progress and cost are the essential elements of project control. It is a general practice for reviews to be made of each project at regular intervals. Analysis and evaluation that takes place during the programme review stage would highlight any deviation from the objectives or predicted results. The time and expense involved in writing a network analysis computer program is considerable. An examination of the various specifications would allow determination of their suitability for the particular project in hand.

Publisher Summary This chapter discusses the importance of proper management during radio installations by an organization. Many radio installations have suffered heavy fire losses throughout the world because management have not developed their fire protection arrangements sufficiently enough to match technical advances that have been taking place with their radio equipment. In larger organizations with high capital investment, management must ensure the appointment of responsible people in the organization to coordinate and supervise an effective fire prevention and protection program. Management has a responsibility to ensure that there is sufficient staff adequately instructed and supported to effectively control and extinguish the types of fires, which could reasonably be expected within the technical plant and buildings under their control. Management must be willing to consult with and accept recommendations from various authorities and organizations that have the technical knowledge and expertise.

This chapter focuses on project management and quality control (PERT)/cost system, which is an extension of PERT/time technique. The PERT/cost system is concerned with the one-time-through programs such as a station construction or a system installation, rather than the repetitive manufacturing situation, such as amplifier or television set production, where costs are allied with the number of items manufactured. The inbuilt selective reporting system enables each level of project management to compare the current cost progress with the future cost predictions, as it relates to his responsibilities. The information is presented in a decision-makingform and the manager does not have to review detailed data to evaluate the status of the program under examination. The main features of the system are the project work breakdown structure; work package concept at the lowest level of detail and cost totals for each work package; a man-hour analysis of the project requirements; integration of the expenditure and actual progress of the project work; and reporting on the forecast completion costs of the project.

This chapter focuses on site installation and construction in radio engineering projects. In radio engineering, installation, and construction projects, delays for several reasons affect about 25% of the items on the critical path of the network. Commissioning of the station or system to the on-air stage is regarded as a part of the site installation and construction works, and is included in the plan. Thecommissioning phase of many projects covers a wide area of the radio-engineering field and necessitates an understanding of many practical and theoretical considerations. The installation and commissioning of small projects might be carried out by a single team of skilled specialists, each familiar with the essential features of the project. The site and its associated problems require the greatest personal effort in understanding and resolve between those charged with the various responsibilities of supervision and erection. The site inspection of the work progress is also an opportunity for a general interchange of ideas and techniques being used successfully or sometimes unsuccessfully on other current installation and construction works.

Publisher Summary This chapter presents several case studies taken from fire department and radio station reports. In one case study, a fire incident occurred in a 2 kW medium frequency broadcast transmitter operating in an unattended mode and caused extensive damage to the working transmitter of a main/standby combination. At the time of the fire, the station was fitted with heat sensitive devices located in the ceiling. In another case study, the sound studios of a broadcast station were damaged when fire broke out in a multi-storey building. The studios were located on the 11th floor but the fire started on the 13th floor. The fire, which occurred in the early afternoon, commenced in an unattended work area. The area was unlined, steel reinforced concrete construction and this together with the limited amount of flammable material stored, helped to contain the fire. However, limited access and heavy smoke made necessary the use of a large volume of water over an extended period of several hours.

This chapter focuses on the budgets and costing aspect of radio engineering projects. Budgeting is a means of planning so that the best possible use might be made of all available resources in achieving certain defined objectives. It is an integral part of forward engineering planning and provides the means for measuring the efficiency with which these plans are put into operation. In monetary terms, the budget establishes an objective of performance; having been established with sufficient detail, it serves as a guide, as time elapses, against which to check actual performance and in turn to keep the performance on program. As a general rule, budgets for the provision or maintenance of the radio engineering facilities pass through three stages of development, namely, preparation of needs or initial overall requirements, preparation of the coordinated realistic requirements, and preparation of the coordinated realistic requirements. Costing involves finding the cost of undertaking separate classes of work such as erection and maintenance of masts, installation and maintenance of radio equipment, power plant or finding out the cost of undertaking separate types of work.

Proper planning is essential for any radio projects. The planning and tender schedule stages fix the direction, and have considerable influence on the success of nearly every project. The need for proper planning by any organization arises from economic considerations and the availability of manpower resources. To make sure that the benefits to be gained from working to comprehensive and properly planned programs are not lost by failures of implementation, procedure for monitoring and reporting progress on all planning and tender stages must be set down. The planning stage is an important stage in any project and the work calls for staff with the broadest background. The project engineer and his staff are responsible for achieving the objectives, it is reasonable to expect that they should plan and measure their accomplishment. After the management has agreed upon the overall broad plan and schedule for the project, the detailed aspects of the planning and scheduling can be undertaken. On completion of the initial planning phase of a proposal, management approval has to be obtained for engineering concurrence and the allocation of funds before the work can proceed.

This chapter focuses on the philosophy and plans related to safety in the field of radio engineering. Radio engineering is associated with several hazards including high voltages used with high power transmitters, the radio frequency voltages encountered on transmission lines, and antenna systems. The basic philosophy should be to concentrate on the detection of hazards and then to eliminate them as far as possible. This applies to all phases of the work from planning, to design, construction, installation, testing, operations, and maintenance. Safety programs are aimed at preventing workmen injuring themselves and others. It is accomplished through the use of the safeguards supplemented by instruction at regular intervals. The continuing educational program is necessary because the absence of accidents lulls personnel working in hazardous areas or they might be so used to the presence of danger that they are no longer conscious of it. In the development of an emergency organization plan, some of the important actions that management must take are train and periodically check all station personnel in emergency procedures; assign and periodically check specific responsibilities; post emergency instructions in appropriate locations throughout the station; and familiarise personnel who would carry out the emergency plan with the alternative facilities, and test all details of the plan in advance.

Publisher Summary This chapter focuses on the protection of radio equipment. All radio equipment should be provided with protective circuits. There are two main reasons for providing protection, namely, to prevent a component or equipment assembly reaching a temperature that might result in fire and to minimize the hazards to staff in the event of an unsafe condition developing. Radio equipment that would require maintenance work upon it should have approved means of disconnecting it from all unearthed conductors of its supply circuit. Care must be taken in the design of the control circuit or mechanism that power cannot be restored while work is in progress. To provide adequate protection for staff, equipment, and plant against lightning, it is necessary to install facilities by which a discharge is not required to pass through a path of high impedance. The station property should also be enclosed by a fence of proper height and construction that would prevent access to the property by unauthorized persons and grazing animals.

This chapter discusses the typical specifications related to radio engineering projects. “Bond” refers to a low impedance connection between two points, whereas “bonding” is the process in which various components or modules of an assembly are electrically connected by means of a low impedance conductor. “Earth” means a point of “zero” or “reference” potential, which is equipotential with all other earth points of the system such as frame, cubicle, and chassis. All earthing in this specification should be by the multipoint principle. “Earthing” is the process of connecting materials, equipment to points of zero or reference potential. “Standards” refers to the standard specifications and the codes prepared and issued by approved standards associations or institutions such as British standards institution, the American society for testing materials, United States of America standards institute, and standards association of Australia.

This chapter focuses on cost comparison studies that determine which of the alternatives, providing approximately the same facilities has the least cost expressed as the present worth of all associated expenditure and to show the difference between the alternatives. There are many factors involved in a cost comparison and for the specific system, all must be considered. It is necessary to compare the alternatives over a period that is sufficiently long to reveal the cost adequately, but not too long, because the reliability of forecasts decreases with the length of the period covered. The length of the period chosen would depend on the nature of the scheme, but normally for radio engineering purposes would seldom exceed 20 years. In addition to comparing costs of alternative systems, cost studies also allow the engineer to determine the relative cost of each major element of the project. Broadcast station estimates include the costs of transmitters, program input equipment, test equipment, antenna, transmission lines, matching equipment, power supply, program lines, maintenance spares and other equipment, and their installation.

Publisher Summary This chapter discusses the issue of corrosion encountered by radio engineers. Many metals and alloys used in radio engineering suffer oxidation when exposed to the atmosphere. In the majority of cases such oxidation is not damaging and is protective. An unprotected steel tower would rust because of oxygen and moisture in the atmosphere. This rusting process is damaging to the structure and must be prevented. Copper transmission line and antenna conductors, on the other hand, acquire a coating of basic copper carbonate in ordinary atmospheres and is not damaging to the mechanical properties of the line. However, where the line carries high voltage, corona would occur at a lower voltage with such coating, than for a new polished conductor. There are several methods that help in protecting against corrosion including protective coatings, sacrificial protection, and use of compatible metals.

This chapter focuses on how to increase the productivity and efficiency in radio engineering projects. The continuous pressure by management for greater productivity to meet high rates of demand with limited fund allocations has called for greater skill and ability on the part of the engineering workforce. The improvement in productivity in radio engineering can be achieved by improvements in the design of equipment, plant and materials to give greater reliability and to require less installation and maintenance manpower; improvements in the methods and techniques of installation; the use of cost analysis and performance studies; substitution or elimination of parts, finishes or unnecessary operations; and better organizational practices for carrying out work, aimed at reducing ineffective time to a minimum. Greater production or output does not necessarily mean higher productivity. Production can be increased simply by using more resources, provided that more resources are available. Efficiency denotes a comparative grade of operational or structural excellence ascertained by measurement and calculation. Economic efficiency within an organization involves problems of selecting the combinations of resources to use and the techniques to use in carrying out the project work. The choice of techniques to use would depend upon relative resource cost and the quantity of work to be performed or product to be produced.

This chapter focuses on the importance of following the environmental obligations in mast and tower design. In several countries, many large scale construction works stimulated a growing realization that the impact of development and expansion were too high and environmental protection emerged as an objective to be considered along with the economic, technical, and aesthetic considerations. Environmental improvements in radio engineering are most readily discernible to the general public in the design of structures to support broadcasting, television, and radio-communication antenna systems. There is a clear responsibility on individuals and organizations to include aesthetic considerations in all aspects of the radio engineering design phase, particularly in the external works such as masts and towers and other structures associated with antenna systems. By careful forethought and planning most developments can be environmentally acceptable. An environment impact assessment process provides a framework for ensuring that all factors are included in reaching decisions about projects and that the fullest consideration has been taken of all aspects of the quality of the environment.

Publisher Summary This chapter focuses on the importance of economic studies in radio engineering projects. Radio engineering installations are characterized by large equipment and plant investments that turn over slowly and cannot be retrieved except by the slow process of write off through depreciation channels. The principles of engineering economic studies are the same whether applied to internal equipment such as transmitters, amplifiers, studio facilities, or to external plant such as masts, towers, antennas, and transmission lines. The economics used involve money, its time value and the interest rate applied to the money. It is significant to note that an engineering economic selection study does not indicate which proposal or scheme provides the most profit. It indicates which proposal or scheme is the least expensive. In making the economic study of alternatives, the only factors that require consideration are the ones that differ with each scheme. The common factors can be ignored as it is only the real differentials that are significant in aneconomic study.

This chapter discusses the hazards relating to the installation and construction of a large radio station. The installation of a large radio station requires the assembly of a series of large shipping packages, and considerable care must be exercised by workmen during handling operations. In many cases, special facilities and planning are required to cope with transport and on-site handling problems. Advance traffic negotiations and pre-planning of route might be essential, particularly where the station is located in an isolated area with poor roads and light traffic bridges. Many poisonous, corrosive, flammable, asphyxiating, explosive and otherwise harmful substances are used in radio installation and maintenance activities. The storage and handling of these substances should be such as would prevent harmful exposure of workmen to the effects of such substances. For a large project involving the construction of masts, transmission lines, matrix switch, transmitters, and associated equipment, it would be desirable to establish the station permanent workshop as soon as access is given to the main building, and before the commencement of the construction work proper.

External plant designs in radio projects are rarely truly repetitive. Four critical areas are involved in large external plant projects. These are masts and towers, antenna systems, transmission lines, and the line switching system. If these areas are properly programmed, the rest of the site work can be made to fit into the network with little difficulty. There are two accepted methods of handling basic design, namely, the detailed design scheme and the sketch design scheme. In detailed design scheme, considerable time and effort is spent on working up a design in detail before submitting a tender. While in the sketch design scheme, sketch design is produced in a relatively short period, sufficient only for pricing and selecting a contractor. The selected contractor would be given a letter-of-intent to work up the design in detail by joint consultation. The firm contract would then be placed after agreeing on the worked-up design. Programs for external plant works, or any type of radio engineering works might be elaborate or they might be simple. The type of programming arrangement that is used would depend on the class, complexity, and magnitude of the work.

This chapter discusses the inspections and acceptance tests that are carried out in radio engineering projects. The inspections and tests to be carried out on an item of equipment or plant would vary with the nature of the item and the specification requirements. The inspecting officer uses three levels of severity in inspection: normal, tight, and reduced. Normal severity is used as long as the material offered is satisfactory. Tight severity is applied for inspection of material or work that has been re-offered, after a previous rejection, and reduced severity might be used where high rate of acceptance has been obtained on normal severity or the inspector considers it to be desirable. The classification of defects forms the basis of statistical sampling methods and is the first step in the assessment of quality. Acceptance testing of systems such as radio communication systems, broadcast stations, and television stations is required to prove that the system meets all applicable performance and/or contractual specifications. Some equipment and plant debugging and correction of minor discrepancies are expected during these tests.

This chapter discusses the problem associated with the use of oil insulation transformers in the larger radio transmitters. The high flammability of the oil present a considerable fire hazard to radio transmitters. Fires in oil insulated transformers and reactors can be intense and it is important that their location is carefully planned. Some transformers have been known to burn for several hours before being brought under control. After power has been disconnected, such fires can be extinguished by any of the several methods of extinguishing oil fires. If the power cannot be disconnected, carbon dioxide, vaporizing liquids or dry chemical media might be safely employed. Small hand extinguishers would be effective only on minor fires. Extensive transformer fires in a vault can be dealt with most effectively by flooding the room with foam or carbon dioxide. Short circuits and recycling can also result in coil conductors of the transformer to be violently displaced as a result of internal unbalanced electromagnetic conditions. With concentrically wound primary and secondary coils, the horizontal axes might not coincide and vertical force acting upon the coils is introduced in addition to the usual radial one.