bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cooling Methods for Railway Tunnels
Authors: Barrow H , Pope C W 
Published: February 2007

In this paper the cooling of a railway tunnel and its environment is investigated, with particular reference to a study of possible methods for reducing both local and overall average tunnel air temperatures. Both passive and supplementary cooling of a tunnel are considered and then various practical systems are proposed for those situations where passive cooling alone may be inadequate. In some cases, calculations for realistic conditions are made using the First Law of Thermodynamics to assess the efficacy of the system from the thermal point of view. It is concluded that with the advent of increasing energy dissipation, as a consequence of increase in tunnel usage, thermally efficient and cost-effective cooling systems must be developed if temperatures are to be maintained at acceptable levels.
Optimization of Tractor Propeller/Wing Configurations
Authors: Veldhuis L L M 
Published: February 2007

In this paper, a rapid, approximate calculation method for optimal lift distributions of tractor propeller/wing configurations will be formulated and discussed. Some numerical studies, performed with a computer program containing the coded method, reveal that substantial performance benefits can be obtained by adapting the wing geometry and twist distribution to generate optimum lift distribution. The example calculations show that the lift distribution for minimum induced drag differs significantly from the elliptic loading. Furthermore, the propeller angle of attack seems to have a dominant influence on the wing performance. Mounting the propeller at a negative (tilt down) angle with reference to the wing suggests a strong reduction of overall wing induced drag. Moreover, the wing efficiency is found to be strongly dependent on the spanwise propeller position. To produce realistic lift distributions the effect of profile drag is incorporated in the model. Experimental verification of the presented theory using data from simple propeller/wing windtunnel models proves the validity of the method for preliminary design purposes.
Considerations of the All Electric (Accessory) Engine Concept
Authors: Jones R I 
Published: February 2007

The concept of the all electric (accessory) engine (AEE) involves the use of an electrical machine integrated on an engine main shaft acting as a starter generator, providing power to both engine and airframe systems. Through removal of the various constraints caused by the present mechanical accessory drives, this concept apparently provides a number of advantages. However, the concept of an AEE has been around for some years and yet has not been adopted to-date. A brief review of electrical machine types previously considered as internally mounted starter/generators highlights basic problems of the concept. The reasons for favouring the Switched Reluctance Machine for this application are then explained and some present and planned developments on this basis outlined. An approximate sizing of starter/generators to replace shaft off-takes alone and bleed in additions in a civil turbofan application is presented, showing more detailed design considerations. Other system component aspects and concerns are also covered before addressing the effects on the ease of adopting the AEE concept of likely future changes to civil engines. Major differences relative to the civil case are indicated for other engine type applications. Conclusions are then drawn on the likely future of the AEE concept.
A Strategy for the Verification of Tolerances by Coordinate Measuring Machines
Authors: Medland A J , Mullineux G , Rentoul A H 
Published: February 2007

Tolerance definitions and standards have been derived from manual inspection procedures. These interpret manufacturing errors through the use of comparative instruments, such as straight edges and height gauges. These tolerancing forms cannot be applied directly to inspection by coordinate measuring machines, where points on an object are sampled and assembled geometrically to allow features to be calculated. In this paper an alternative approach is presented in which all tolerance conditions are recast into a series of allowable spherical deviations spread across the features to be measured. The distribution of these spherical zones and their radii are chosen, at the design stage, to provide checks on the various tolerance conditions required and to reflect the degree of confidence in the surface conditions provided by the manufacturing processes. This approach has been employed within an automated inspection procedure to allow both top-down and bottom-up error checking procedures to be employed.
Cable Stretch Asymmetries in Multi-Cable Spreader Suspension Systems Undergoing Combined Translations and Rotations
Authors: Morrish L , Cartmell M P , Taylor A J 
Published: February 2007

The work presented in this paper proposes that for widely spaced cable reeving configurations in container-handling cranes there is an interesting, and unexpectedly useful, phenomenon defined henceforth as geometrical extension which gives rise to unevenly distributed cable stretch and, hence, uneven tensions across the system. Geometrical extension is entirely caused by the reluctance of the trolley, spreader and cable system to conform, as a whole, to certain overall shapes. Such shapes are developed because of the various translational and rotational motions which can be experienced at the trolley (that is at the attachment point of the cables running down to the spreader). Other cables stretch effects, such as those due to static and dynamic (inertia) loads, are additional to the geometrical extension (which can, in some circumstances, manifest as a compression instead). The net effect of cable stretch asymmetries is to stiffen up the suspension for certain cases of translation and rotation. This has a direct, and useful, influence for anti-sway control.
New Concept of Automatic Control for a Passenger Car Clutch
Authors: Esenovsky-Lashkov Y , Polyak D 
Published: February 2007

This paper highlights the main functions of clutch automatic control systems. These are: forced clutch disengagement during gear shifting and when the engine falls below its minimum operating speed; forced clutch engagement under conditions of increasing engine speed or vehicle speed at a preset level or at a definite throttle position; adjustment of clutch friction torque, depending on the control parameter used. To achieve this, a closed-loop automatic control system is required. The system compares control signals with feedback from a selected parameter and generates commands for changing clutch friction torque. At present some automatic clutch systems use either the position of the accelerator pedal (‘Drivematic’ and ‘Guidosimplex’) or engine speed (ACTS) as the control parameter. The feedback parameter in these systems is the position of the clutch drive element. Comparison of the two systems shows that those using engine speed as the control parameter are more advanced, although their design is more complex. Engine speed is also used in the system of automatic electrovacuum friction clutch control (EPS) designed at the Central Automobile and Automobile Engine Scientific Research Institute (NAMI), but the principle of operation is totally different from existing systems. Particular features of this system are as follows: all necessary modes of automatic control are provided by only one multi-function electromagnet acting on the vacuum valve in the clutch actuating servo chamber; the feedback is dependent on the position of the clutch actuator and is provided by a spring acting on the armature of the valve drive electromagnet—the force of this spring changes in proportion to the position of the clutch actuator; clutch friction torque control as a function of engine speed is provided by changing the current strength in the electromagnetic winding—these changes are initiated by the electronic control unit of the automatic control system. To achieve the optimal performance of modern high-speed engines in combination with an automatic clutch system, all elements of the clutch control system must have minimal delay in converting input signals into control signals. This requirement resulted from an investigation of the EPS mathematical model comprising three non-periodic dynamic elements. The same results were experimentally proved when amplitude and phase frequency characteristics of the control system were measured. It was shown in particular that the time constants of dynamic elements must not exceed 0.04–0.06 s. This required the application of a brand new engineering circuit for designing the EPS electronic unit. The EPS system is now in mass production and is standard equipment for some models of small passenger cars manufactured in the former Soviet Union. The system has been patented in the United States, Japan, Germany, Great Britain, France and Italy.
Aerodynamic Drag on Trains in Tunnels Part 1: Synthesis and Definitions
Authors: Vardy A E 
Published: February 2007

Aerodynamic drag on trains in tunnels includes friction drag and pressure drag, which are respectively the algebraic sums of the longitudinal components of all shear and normal forces on the train surfaces. The first of these is broadly similar to its counterpart in the open. The second is shown to include two effects that are usually negligible in the open. It is shown that the overall drag force must be regarded as the sum of individual components, each of which behaves differently from the others. The components can be represented by non-dimensional coefficients whose numerical values are nearly constant for a wide range of train journeys. In contrast, the overall drag coefficient is shown to vary significantly, even during any particular journey. The principal causes of aerodynamic drag in tunnels are also the principal causes of pressure waves that give rise to potential aural discomfort for passengers. It is argued that a common method of analysis is appropriate for the prediction of both of these effects. Ill-defined train areas are shown to be a potentially serious source of confusion in the estimation and interpretation of drag coefficients. The relevant train area is shown to be its aerodynamic area, the definition of which is explained.
Data Bus Technology Applications—Boeing 777 Autothrottle Servo Motor
Authors: Wilkinson D 
Published: February 2007

On the Boeing 777 aircraft, two autothrottle actuators are required, one for each throttle lever, both controlled by either one of two computers. The consequent potential need for four remote servo-amplifiers has been eliminated by using two ‘smart’ autothrottle servo motor units (ASMs) independently controlled by ARINC 429 data bus rate command signals from the active computer. The development of the B777 ASM from a servo motor unit used on B727 is recounted and the ASM design and ARINC 429 data bus control architecture are described in detail.
Fin Buffeting Characteristics of a Generic Single Fin Aircraft
Authors: Chesneau T R , Wood N J 
Published: February 2007

Experiments have been performed to investigate the fin buffeting characteristics of a generic single fin aircraft. A variety of configurations, including high wing, mid wing and low wing have been examined, some with the addition of leading edge extensions, foreplanes and cheek intakes. The fin buffeting was measured using a flexible fin, which was related to the buffet pressure flowfield using data from an alternative, pressure tapped, rigid fin. Results have been obtained over a wide range of angles of attack at low subsonic speeds. The production of upstream vortices affects the progression of the primary wing vortex with angle of attack to alter the fin buffeting response. The results indicate that the high wing configurations are sensitive to the presence of additional vortex pairs emanating from forebody features. For low wing configurations, peak buffeting magnitudes may be significantly affected by foreplane incidence in a canard configuration. The interaction between foreplane, wing and body vortices is complex and may result in either reduced or increased levels of buffeting response.
Computer Simulation of the Bi-Stable Valve in the A340 Landing Gear
Authors: Tilley D G , Tomlinson S P 
Published: February 2007

The increasing use of simulation for both circuit and component analysis in the aircraft industry has come about due to the requirement for acceptable transient as well as steady state performance of aircraft systems. The computer simulation package, Bathfp, developed at the Fluid Power Centre, University of Bath, is suitable for investigations into both of these. Utilities are provided which allow a model of a complicated system or component to be built up from its elements, which can be introduced to the model library of components so that particular dedicated areas of interest such as flight control actuation systems and braking and landing gear may be examined in detail. Component models enable the internal details of valves, pumps, motors, actuators and other elements to be simulated to a high degree of accuracy. This paper describes the application of the simulation package to perform a detailed analysis of the bi-stable valve in the A340 landing gear shock absorber. In the original design, a malfunction of the valve during impact on landing was clearly identified by an experimental test. Parametric variations are made in the simulation to identify the possible cause of the malfunction.
Ultra-High Molecular Weight Polyethylene Wear Debris Generated in Vivo and in Laboratory Tests; the Influence of Counterface Roughness
Authors: Hailey J L , Ingham E , Stone M , Wroblewski B M , Fisher J 
Published: February 2007

The objective of this study was to investigate the effect of counterface roughness and lubricant on the morphology of ultra-high molecular weight polyethylene (UHMWPE) wear debris generated in laboratory wear tests, and to compare this with debris isolated from explanted tissue. Laboratory tests used UHMWPE pins sliding against stainless steel counterfaces. Both water and serum lubricants were used in conjunction with rough and smooth counterfaces. The lubricants and tissue from revision hip surgery were processed to digest the proteins and permit filtration. This involved denaturing the proteins with potassium hydroxide (KOH), sedimentation of any remaining proteins, and further digestion of these proteins with chromic acid. All fractions were then passed through a 0.2 μm membrane, and the debris examined using scanning electron microscopy. The laboratory studies showed that the major variable influencing debris morphology was counterface roughness. The rougher counter-faces produced larger numbers of smaller particles, with a size range extending below 1 μm. For smooth counterfaces there were fewer of these small particles, and evidence of larger platelets, greater than 10 μm in diameter. Analysis of the debris from explanted tissues showed a wide variation in the particle size distribution, ranging from below 1 μm up to several millimetres in size. Of major clinical significance in relation to osteolysis and loosening is roughening of the femoral components, which may lead to greater numbers of the sub-micron-sized particles.
Theory and Practice of Meniscal Knee Replacement: Designing against Wear
Authors: O'Connor J J , Goodfellow J W 
Published: February 2007

This paper attributes the high rate of high-density polyethylene (HDP) wear in many knee prostheses to incongruity of their articular surfaces. The authors discuss the anatomical and kinematic features of the knee which have led most designers to choose incongruous surfaces and review the reasons for employing free bearings, analogues of the natural menisci, to provide congruity without restriction of movement. There are theoretical reasons against employing freely mobile bearings in the absence of a functioning anterior cruciate ligament (ACL) and the authors' experience has confirmed this limitation in practice. It is concluded that, in bicompartmental replacement, the movements of the meniscal bearing should be limited in the anteroposterior direction. For unicompartmental arthritis, an unconstrained bearing can be employed if, as is usually the case, all ligaments are intact.
Determination of Viscosity and Pressure in an Elastohydrodynamic Rolling Contact by using Optical Interferometry: A Theoretical Study
Authors: Östensen J O , Larsson R , Venner C H 
Published: February 2007

Optical interferometry has been used during the last 30 years for film thickness measurements in elastohydrodynamic (EHD) contacts. In the work presented in this paper the possibility of using optical interferometry for determining pressure and apparent viscosity in a fully flooded EHD point contact has been theoretically investigated. The pressure in the contact is computed from elastic deformation theory and force balance. The apparent viscosity can be obtained from the Reynolds equation when the film thickness and the pressure are known. To theoretically examine the sensitivity to measurement errors, different errors have been implemented in a set of ‘exact’ numerical data. From the theoretical study it can be seen that a film thickness map obtained from optical interferometry can be used for determination of both pressure and apparent viscosity measurement in an EHD point contact. The simulated errors that have been used do not influence the pressure within the Herzian region by more than a few per cent. However, to obtain reliable results from the apparent viscosity calculations, the measurements of film thickness, load and elastic modulus must be very accurate. It is seen, for example, that the resolution of the film thickness measurement has to be less than 1 nm to achieve high accuracy.
Schizophrenia: Multi-Attribute Utility Theory Approach to Selection of Atypical Antipsychotics
Authors: Bettinger Tawny L , Shuler Garyn , Jones Donnamaria R , Wilson James P 
Published: February 2007

Background: Current guidelines/algorithms recommend atypical antipsychotics as first-line agents for the treatment of schizophrenia. Because there are extensive healthcare costs associated with the treatment of schizophrenia, many institutions and health systems are faced with making restrictive formulary decisions regarding the use of atypical antipsychotics. Often, medication acquisition costs are the driving force behind formulary decisions, while other treatment factors are not considered. Objective: To apply a multi-attribute utility theory (MAUT) analysis to aid in the selection of a preferred agent among the atypical antipsychotics for the treatment of schizophrenia. Methods: Five atypical antipsychotics (risperidone, olanzapine, quetiapine, ziprasidone, aripiprazole) were selected as the alternative agents to be included in the MAUT analysis. The attributes identified for inclusion in the analysis were efficacy, adverse effects, cost, and adherence, with relative weights of 35%, 35%, 20%, and 10%, respectively. For each agent, attribute scores were calculated, weighted, and then summed to generate a total utility score. The agent with the highest total utility score was considered the preferred agent. Results: Aripiprazole, with a total utility score of 75.8, was the alternative agent with the highest total utility score in this model. This was followed by ziprasidone, risperidone, and quetiapine, with total utility scores of 71.8, 69.0, and 65.9, respectively. Olanzapine received the lowest total utility score. A sensitivity analysis was performed and failed to displace aripiprazole as the agent with the highest total utility score. Conclusions: This model suggests that aripiprazole should be considered a preferred agent for the treatment of schizophrenia unless found to be otherwise inappropriate.
Assessment of point and non-point pollution associated with the power generation sector in South Africa
Authors: van Zyl H.D. , Heath R.G. 
Published: February 2007

Access to water and water availability remains a key factor in ensuring the sustainability of development in Southern Africa. The need for guidelines to improve management of this valuable resource, and to regulate pollutant discharge, is therefore of national interest.
A new and growing threat to our natural water resources is non-point source (NPS) pollution. The important distinction between point pollution and NPS pollution is that the latter is difficult to identify and the entry point of contamination to resources is diffuse and not limited to a single location. NPS pollution associated with power generation includes, but is not limited to, atmospheric deposition resulting from emissions (air and water), leachate from coal storage piles and runoff from impervious areas which are covered with dust fallout from coal and ash handling operations. Emissions of primary concern are sulfur, nitrogen and mercury.
Carcinosarcoma of the spleen: literature review of a very rare tumour
Authors: Rao Annapurna , Mathew George , Marimuthu Kalimuthu , Pandey Urmila , Worlding Jane 
Published: February 2007

Abstract
Carcinosarcomas are rare tumours, which have both epithelial, and connective tissue elements. They are most commonly seen in the female genital tract. Rarely they arise from the gastrointestinal tract. We report a case of Carcinosarcoma arising as a primary in the spleen of a male aged 60yrs. The most unique feature of this tumour is the presence of osteosarcomatous element. This report highlights the importance of clinical awareness of such rare tumours and gives a brief overview on presentation, probable aetiology, diagnosis and management with literature review of carcinosarcoma.
Are Ottawa knee rules useful in actual trauma care?
Authors: Nagpal Kamal , Marathe Mandar 
Published: February 2007

Abstract
Acute knee injuries are a common presentation to the emergency department(ED). Ottawa knee rules (OKR) have shown to reduce the number of radiographs in these patients in North American studies and a fracture rate of 5% has been reported. Based on this, we tested the hypothesis that it was possible to decrease the number of x-ray films obtained after a knee trauma without delayed fracture diagnosis by means of the Ottawa knee rules in British set up. A total of 118 adult patients with acute Knee injuries were studied. A checklist in an easy-to-use format was produced to act as an aide-memoir and to encourage clinicians to apply the OKR in their decision making. Sixty patients were studied before introducing the check list stickers of OKR and fifty eight were studied after introducing the stickers. The OKR were found to have been obeyed in 24 (40%) of patients in the group which did not have stickers. In the group assessed without an OKR sticker, 28 (46.7%) of patients had knee radiography, compared with 29 (50%) of patients in the group who were assessed with an OKR sticker. There was no decrease in the number of x-rays after following the Ottawa Knee Rules (OKR).
Breast cancer incidence and mortality in Lower Silesia (Poland) between 1984 and 2003 — trends and perspectives
Authors: Bębenek Marek , Pudełko Marek , Błaszczyk Jerzy 
Published: February 2007

Abstract
The purpose of the study was to determine the epidemiological characteristics of breast cancers diagnosed among Lower Silesian women between 1984 and 2003. Data from the Lower Silesian Cancer Registry on the incidence and mortality of breast neoplasms in the Lower Silesian province were analyzed. The annual number of breast cancers and cancer-related deaths increased markedly between 1984 and 2003. The non-standardized coefficients of incidence in the large cities of Wroclaw, Legnica, and Walbrzych were markedly higher than in the other counties of the province. The number of tumors detected with diameters ≤5 cm increased from 57% in 1984 to 81% in 2003. The increasing incidence of breast cancer seemed to be mostly related to the socioeconomic characteristics of Lower Silesian women. Although a down-staging due to better care reflects some positive trends, the outlook for breast cancer in Lower Silesia remains unfavorable.