15 resultados para cost comparison
em Aston University Research Archive
Resumo:
In the general introduction of the road-accident phenomenon inside and outside Iran, the results of previous research-works and international conferences and seminars on road-safety have been reviewed. Also a sample-road between Tehran and Mashad has been investigated as a case-study. Examining the road-accident data and iriformation,first: the information presented in road-accident report-forms in developed countries is discussed and, second: the procedures for road-accident data collection in Iran are investigated in detail. The data supplied by Iran Road-Police Central Statistics Office, is analysed, different rates are computed, due comparisons with other nations are made, and the results are discussed. Also such analysis and comparisons are presented for different provinces of Iran. It is concluded that each province with its own natural, geographical, social and economical characteristics possesses its own reasons for the quality and quantity of road-accidents and therefore must receive its own appropriate remedial solutions. The question~ of "what is the cost of road-accidents", "why and how evaluate the cost", "what is the appropriate way of approach to such evaluation" are all discussed and then "the cost of road-accidents in Iran" based on two different approaches: "Gross National Output"and "court award" is computed. It is concluded that this cost is about 1.5 per cent of the country's national product. In Appendix 3 an impressive example is given of the trend of costs and benefits that can be attributed to investment in road-safety measures.
Resumo:
A quantitative comparison of up to 40 Gb/s low-cost orthogonal frequency-division multiplexing access (OFDMA)-passive optical networks (PON) implementations for both upstream (US) and downstream (DS) directions is evaluated based on different modulation and detection techniques. © 2012 IEEE.
Resumo:
Extensive numerical investigations are undertaken to analyze and compare, for the first time, the performance, techno-economy, and power consumption of three-level electrical Duobinary, optical Duobinary, and PAM-4 modulation formats as candidates for high-speed next-generation PONs supporting downstream 40 Gb/s per wavelength signal transmission over standard SMFs in C-band. Optimization of transceiver bandwidths are undertaken to show the feasibility of utilizing low-cost and band-limited components to support next-generation PON transmissions. The effect of electro-absorption modulator chirp is examined for electrical Duobinary and PAM-4. Electrical Duobinary and optical Duobinary are powerefficient schemes for smaller transmission distances of 10 km SMFs and optical Duobinary offers the best receiver sensitivity albeit with a relatively high transceiver cost. PAM-4 shows the best power budget and costefficiency for larger distances of around 20 km, although it consumes more power. Electrical Duobinary shows the best trade-off between performance, cost and power dissipation.
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This thesis presents a comparison of integrated biomass to electricity systems on the basis of their efficiency, capital cost and electricity production cost. Four systems are evaluated: combustion to raise steam for a steam cycle; atmospheric gasification to produce fuel gas for a dual fuel diesel engine; pressurised gasification to produce fuel gas for a gas turbine combined cycle; and fast pyrolysis to produce pyrolysis liquid for a dual fuel diesel engine. The feedstock in all cases is wood in chipped form. This is the first time that all three thermochemical conversion technologies have been compared in a single, consistent evaluation.The systems have been modelled from the transportation of the wood chips through pretreatment, thermochemical conversion and electricity generation. Equipment requirements during pretreatment are comprehensively modelled and include reception, storage, drying and communication. The de-coupling of the fast pyrolysis system is examined, where the fast pyrolysis and engine stages are carried out at separate locations. Relationships are also included to allow learning effects to be studied. The modelling is achieved through the use of multiple spreadsheets where each spreadsheet models part of the system in isolation and the spreadsheets are combined to give the cost and performance of a whole system.The use of the models has shown that on current costs the combustion system remains the most cost-effective generating route, despite its low efficiency. The novel systems only produce lower cost electricity if learning effects are included, implying that some sort of subsidy will be required during the early development of the gasification and fast pyrolysis systems to make them competitive with the established combustion approach. The use of decoupling in fast pyrolysis systems is a useful way of reducing system costs if electricity is required at several sites because• a single pyrolysis site can be used to supply all the generators, offering economies of scale at the conversion step. Overall, costs are much higher than conventional electricity generating costs for fossil fuels, due mainly to the small scales used. Biomass to electricity opportunities remain restricted to niche markets where electricity prices are high or feed costs are very low. It is highly recommended that further work examines possibilities for combined beat and power which is suitable for small scale systems and could increase revenues that could reduce electricity prices.
Resumo:
Since 1988, quasi-markets have been introduced into many areas of social policy in the UK, the NHS internal market is one example. Markets operate by price signals. The NHS Internal Market, if it is to operate efficiently, requires purchasers and providers to respond to price signals. The research hypothesis is - cost accounting methods can be developed to enable healthcare contracts to be priced on a cost-basis in a manner which will facilitate the achievement of economic efficiency in the NHS internal market. Surveys of hospitals in 1991 and 1994 established the cost methods adopted in deriving the prices for healthcare contracts in the first year of the market and three years on. An in-depth view of the costing for pricing process was gained through case studies. Hospitals had inadequate cost information on which to price healthcare contracts at the inception of the internal market: prices did not reflect the relative performance of healthcare providers sufficiently closely to enable the market's espoused efficiency aims to be achieved. Price variations were often due to differing costing approaches rather than efficiency. Furthermore, price comparisons were often meaningless because of inadequate definition of the services (products). In April 1993, the NHS Executive issued guidance on costing for contracting to all NHS providers in an attempt to improve the validity of price comparisons between alternative providers. The case studies and the 1994 survey show that although price comparison has improved, considerable problems remain. Consistency is not assured, and the problem of adequate product definition is still to be solved. Moreover, the case studies clearly highlight the mismatch of rigid, full-cost pricing rules with both the financial management considerations at local level and the emerging internal market(s). Incentives exist to cost-shift, and healthcare prices can easily be manipulated. In the search for a new health policy paradigm to replace traditional bureaucratic provision, cost-based pricing cannot be used to ensure a more efficient allocation of healthcare resources.
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Central venous catheters have become an integral part of patient management however they are associated with many complications including infection. Despite efforts being made to reduce the incidence of such infect ions the problem continues to increase and has resource implications for the Health Service. Studies relating to the source of microorganisms causing CVC-associated infection, the cost of such infections and the efficacy of an antimicrobial catheter have been undertaken. Thirty patients who required a CVC as part of their medical management and underwent cardiac surgery had the distal tips of their catheters sampled whilst in situ. Sampling took place within 1 h of catheter placement. Bacteria were isolated from 16% of the catheter distal tips sampled in situ. The guidewires used to insert the devices were also contaminated (50%). When CVC were inserted via a protective sheath, avoiding contact with the skin. the incidence of microbial contamination was reduced. These findings suggest that despite rigorous skin disinfection and strict aseptic technique, viable microorganisms are impacted onto the distal tip of CVC during the insertion procedure. Needleless intravascular access devices have been introduced in order to reduce the incidence of need1estick injury. However, it was unclear whether such connectors would act as a portal of entry for microorganisms to CVC. The efficacy of these devices was investigated. Within the controlled laboratory environment it was demonstrated that needleless devices, when challenged with microorganisms, did not allow the passage of microbes when flu id was injected. This therefore suggested that the devices should not increase the risk of catheter colonisation. When used in clinical practice however microbial contamination of the needleless connectors was 55 % in comparison to the routinely used luer connectors (23%). The cost of infections associated with CVC was determined. Twenty patients catheterised with a CVC designed for long term use who were admitted to hospital with a presumptive diagnosis of catheter-related infection were studied. The treatment given specifically for this infection was costed. The mean cost of such an infection was £ 1781.81. Throughout the UK this may amount to £1.565.906 per annum. The cost of infections associated with CVC designed for short term use was estimated to be between 5 and 7 million pounds per annum in the UK. In an attempt to reduce both the incidence and cost of catheter- related infection antimicrobial CVC have been developed. The efficacy of a novel polyurethane CVC impregnated on both the internal and external catheter surface with the quaternary ammonium compound benzalkonium chloride was investigated. Eighty eight patients received an antimicrobial catheter and 78 patients a conventional polyurethane CVC. The anti-microbial CVC resulted in a reduction in microbial colonisation of the external and internal polymer surfaces as compared to the control device. The observed reduction in microbial colonisation with the anti-microbial CVC may decrease the likelihood of subsequent infection offering a useful approach to the prevention of catheter-related infections.
Resumo:
The work described in the following pages was carried out at various sites in the Rod Division of the Delta Metal Company. Extensive variation in the level of activity in the industry during the years 1974 to I975 had led to certain inadequacies being observed 1n the traditional cost control procedure. In an attempt to remedy this situation it was suggested that a method be found of constructing a system to improve the flexibility of cost control procedures. The work involved an assimilation of the industrial and financial environment via pilot studies which would later prove invaluable to home in on the really interesting and important areas. Weaknesses in the current systems which came to light made the methodology of data collection and the improvement of cost control and profit planning procedures easier to adopt. Because of the requirements of the project to investigate the implications of Cost behaviour for profit planning and control, the next stage of the research work was to utilise the on-site experience to examine at a detailed level the nature of cost behaviour. The analysis of factory costs then showed that certain costs, which were the most significant exhibited a stable relationship with respect to some known variable, usually a specific measure of Output. These costs were then formulated in a cost model, to establish accurate standards in a complex industrial setting in order to provide a meaningful comparison against which to judge actual performance. The necessity of a cost model was •reinforced by the fact that the cost behaviour found to exist was, in the main, a step function, and this complex cost behaviour, the traditional cost and profit planning procedures could not possibly incorporate. Already implemented from this work is the establishment of the post of information officer to co-ordinate data collection and information provision.
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This thesis deals with the problems associated with the planning and control of production, with particular reference to a small aluminium die casting company. The main problem areas were identified as: (a) A need to be able to forecast the customers demands upon the company's facilities. (b) A need to produce a manufacturing programme in which the output of the foundry (or die casting section) was balanced with the available capacity in the machine shop. (c) The need to ensure that the resultant system enabled the company's operating budget to have a reasonable chance of being achieved. At the commencement of the research work the major customers were members of the automobile industry and had their own system of forecasting, from which they issued manufacturing schedules to their component suppliers, The errors in the forecast were analysed and the distributions noted. Using these distributions the customer's forecast was capable of being modified to enable his final demand to be met with a known degree of confidence. Before a manufacturing programme could be developed the actual manufacturing system had to be reviewed and it was found that as with many small companies there was a remarkable lack of formal control and written data. Relevant data with regards to the component and the manufacturing process had therefore to be collected and analysed. The foundry process was fixed but the secondary machining operations were analysed by a technique similar to Component Flow Analysis and as a result the machines were arranged in a series of flow lines. A system of manual production control was proposed and for comparison, a local computer bureau was approached and a system proposed incorporating the production of additional management information. These systems are compared and the relative merits discussed and a proposal made for implementation.
Resumo:
This research was originally undertaken to aid the Jamaican government and the World Bank in making funding decisions relative to improvement of road systems and traffic control in Jamaica. An investigation of the frequency and causes of road accidents and an evaluation of their impact on the Jamaican economy were carried out, and a model system which might be applied was developed. It is believed that the importance of road accident economic and manpower losses to the survival of developing countries, such as Jamaica, cannot be overemphasized. It is suggested that the World Bank, in cooperation with national governments, has a role to play in alleviating this serious problem. Data was collected from such organizations as the Jamaica Ministry of Construction, Police Department, the World Bank, and the World Health Organization. A variety of methodologies were utilized to organize this data in useful and understandable forms. The most important conclusion of this research is that solvable problems in road systems and in traffic control result in the unnecessary loss of useful citizens, in both developed and developing countries. However, a lack of information and understanding regarding the impact of high rates of road accident death and injury on the national economy and stability of a country results in an apparent lack of concern. Having little internal expertise in the field of road accident prevention, developing countries usually hire consultants to help them address this problem. In the case of Jamaica, this practice has resulted in distrust and hard feelings between the Jamaican authorities and major organizations involved in the field. Jamaican officials have found confusing the recommendations of most experts contracted to study traffic safety. The attempts of foreign consultants to utilize a technological approach (the use of coding systems and computers), methods which do not appear cost-effective for Jamaica, have resulted in the expenditure of limited funds for studies which offer no feasible approach to the problem. This funding limitation, which hampers research and road improvement, could be alleviated by such organizations as the World Bank. The causes of high accident rates are many, it was found. Formulation of a plan to address this serious problem must take into account the current failure to appreciate the impact of a high level of road accidents on national economy and stability, inability to find a feasible approach to the problem, and inadequate funding. Such a plan is discussed in detail in the main text of this research.
Resumo:
Desalination of brackish groundwater (BW) is an effective approach to augment water supply, especially for inland regions that are far from seawater resources. Brackish water reverse osmosis (BWRO) desalination is still subject to intensive energy consumption compared to the theoretical minimum energy demand. Here, we review some of the BWRO plants with various system arrangements. We look at how to minimize energy demands, as these contribute considerably to the cost of desalinated water. Different configurations of BWRO system have been compared from the view point of normalized specific energy consumption (SEC). Analysis is made at theoretical limits. The SEC reduction of BWRO can be achieved by (i) increasing number of stages, (ii) using an energy recovery device (ERD), or (iii) operating the BWRO in batch mode or closed circuit mode. Application of more stages not only reduces SEC but also improves water recovery. However, this improvement is less pronounced when the number of stages exceeds four. Alternatively and more favourably, the BWRO system can be operated in Closed Circuit Desalination (CCD) mode and gives a comparative SEC to that of the 3-stage system with a recovery ratio of 80%. A further reduction of about 30% in SEC can be achieved through batch-RO operation. Moreover, the costly ERDs and booster pumps are avoided with both CCD and batch-RO, thus furthering the effectiveness of lowering the costs of these innovative approaches. © 2012 by the authors.
Resumo:
This paper presents an assessment of the technical and economic performance of thermal processes to generate electricity from a wood chip feedstock by combustion, gasification and fast pyrolysis. The scope of the work begins with the delivery of a wood chip feedstock at a conversion plant and ends with the supply of electricity to the grid, incorporating wood chip preparation, thermal conversion, and electricity generation in dual fuel diesel engines. Net generating capacities of 1–20 MWe are evaluated. The techno-economic assessment is achieved through the development of a suite of models that are combined to give cost and performance data for the integrated system. The models include feed pretreatment, combustion, atmospheric and pressure gasification, fast pyrolysis with pyrolysis liquid storage and transport (an optional step in de-coupled systems) and diesel engine or turbine power generation. The models calculate system efficiencies, capital costs and production costs. An identical methodology is applied in the development of all the models so that all of the results are directly comparable. The electricity production costs have been calculated for 10th plant systems, indicating the costs that are achievable in the medium term after the high initial costs associated with novel technologies have reduced. The costs converge at the larger scale with the mean electricity price paid in the EU by a large consumer, and there is therefore potential for fast pyrolysis and diesel engine systems to sell electricity directly to large consumers or for on-site generation. However, competition will be fierce at all capacities since electricity production costs vary only slightly between the four biomass to electricity systems that are evaluated. Systems de-coupling is one way that the fast pyrolysis and diesel engine system can distinguish itself from the other conversion technologies. Evaluations in this work show that situations requiring several remote generators are much better served by a large fast pyrolysis plant that supplies fuel to de-coupled diesel engines than by constructing an entire close-coupled system at each generating site. Another advantage of de-coupling is that the fast pyrolysis conversion step and the diesel engine generation step can operate independently, with intermediate storage of the fast pyrolysis liquid fuel, increasing overall reliability. Peak load or seasonal power requirements would also benefit from de-coupling since a small fast pyrolysis plant could operate continuously to produce fuel that is stored for use in the engine on demand. Current electricity production costs for a fast pyrolysis and diesel engine system are 0.091/kWh at 1 MWe when learning effects are included. These systems are handicapped by the typical characteristics of a novel technology: high capital cost, high labour, and low reliability. As such the more established combustion and steam cycle produces lower cost electricity under current conditions. The fast pyrolysis and diesel engine system is a low capital cost option but it also suffers from relatively low system efficiency particularly at high capacities. This low efficiency is the result of a low conversion efficiency of feed energy into the pyrolysis liquid, because of the energy in the char by-product. A sensitivity analysis has highlighted the high impact on electricity production costs of the fast pyrolysis liquids yield. The liquids yield should be set realistically during design, and it should be maintained in practice by careful attention to plant operation and feed quality. Another problem is the high power consumption during feedstock grinding. Efficiencies may be enhanced in ablative fast pyrolysis which can tolerate a chipped feedstock. This has yet to be demonstrated at commercial scale. In summary, the fast pyrolysis and diesel engine system has great potential to generate electricity at a profit in the long term, and at a lower cost than any other biomass to electricity system at small scale. This future viability can only be achieved through the construction of early plant that could, in the short term, be more expensive than the combustion alternative. Profitability in the short term can best be achieved by exploiting niches in the market place and specific features of fast pyrolysis. These include: •countries or regions with fiscal incentives for renewable energy such as premium electricity prices or capital grants; •locations with high electricity prices so that electricity can be sold direct to large consumers or generated on-site by companies who wish to reduce their consumption from the grid; •waste disposal opportunities where feedstocks can attract a gate fee rather than incur a cost; •the ability to store fast pyrolysis liquids as a buffer against shutdowns or as a fuel for peak-load generating plant; •de-coupling opportunities where a large, single pyrolysis plant supplies fuel to several small and remote generators; •small-scale combined heat and power opportunities; •sales of the excess char, although a market has yet to be established for this by-product; and •potential co-production of speciality chemicals and fuel for power generation in fast pyrolysis systems.
Resumo:
Previous research suggests that the use of modelling and non-food rewards may be effective at increasing tasting, and consequential liking and acceptance, of a previously disliked food. Although successful school-based interventions have been developed, there is a lack of research into home-based interventions using these methods. This study aimed to develop and investigate the efficacy of a parent led home-based intervention for increasing children's acceptance of a disliked vegetable. A total of 115 children aged 2-4 years were allocated to one of four intervention groups or to a no-treatment control. The four intervention conditions were: repeated exposure; modelling and repeated exposure; rewards and repeated exposure; or modelling, rewards and repeated exposure. Children in all of the intervention conditions were exposed by a parent to daily offerings of a disliked vegetable for 14 days. Liking and consumption of the vegetable were measured pre and post-intervention. Significant increases in post-intervention consumption were seen in the modelling, rewards and repeated exposure condition and the rewards and repeated exposure condition, compared to the control group. Significant post-intervention differences in liking were also found between the experimental groups. Liking was highest (>60%) in the modelling, rewards and repeated exposure group and the rewards and repeated exposure group, intermediate (>26%) in the modelling and repeated exposure and repeated exposure groups, and lowest in the control group (10%). Parent led interventions based around modelling and offering incentives may present cost efficient ways to increase children's vegetable consumption.
Resumo:
A valuable alternative to US cardiotocography, for fetal surveillance, can be offered by phonocardiography, a passive and low cost acoustic recording of fetal heart sounds. A crucial point is the exact recognizing of the fetal heart sounds, associated to each fetal heart beat, and then the estimation of FHR signal. In this work, software for FHR assessment from phonocardiographic signals was developed. To check the reliability of the software, obtained results were compared with those of simultaneously recorded cardiotocographic signals. Results seemed to be satisfying, as provided FHR series were almost all confined within FHR-CTG +/- 3 bpm, where FHR-CTG were FHR series provided by commercial US cardiotocographic devices, currently employed in clinical routine.
Resumo:
High precision manufacturers continuously seek out disruptive technologies to improve the quality, cost, and delivery of their products. With the advancement of machine tool and measurement technology many companies are ready to capitalise on the opportunity of on-machine measurement (OMM). Coupled with business case, manufacturing engineers are now questioning whether OMM can soon eliminate the need for post-process inspection systems. Metrologists will however argue that the machining environment is too hostile and that there are numerous process variables which need consideration before traceable measurement on-the-machine can be achieved. In this paper we test the measurement capability of five new multi-axis machine tools enabled as OMM systems via on-machine probing. All systems are tested under various operating conditions in order to better understand the effects of potentially significant variables. This investigation has found that key process variables such as machine tool warm-up and tool-change cycles can have an effect on machine tool measurement repeatability. New data presented here is important to many manufacturers whom are considering utilising their high precision multi-axis machine tools for both the creation and verification of their products.
Resumo:
BACKGROUND: Heavy menstrual bleeding (HMB) is a common problem, yet evidence to inform decisions about initial medical treatment is limited. OBJECTIVES: To assess the clinical effectiveness and cost-effectiveness of the levonorgestrel-releasing intrauterine system (LNG-IUS) (Mirena(®), Bayer) compared with usual medical treatment, with exploration of women's perspectives on treatment. DESIGN: A pragmatic, multicentre randomised trial with an economic evaluation and a longitudinal qualitative study. SETTING: Women who presented in primary care. PARTICIPANTS: A total of 571 women with HMB. A purposeful sample of 27 women who were randomised or ineligible owing to treatment preference participated in semistructured face-to-face interviews around 2 and 12 months after commencing treatment. INTERVENTIONS: LNG-IUS or usual medical treatment (tranexamic acid, mefenamic acid, combined oestrogen-progestogen or progesterone alone). Women could subsequently swap or cease their allocated treatment. OUTCOME MEASURES: The primary outcome was the patient-reported score on the Menorrhagia Multi-Attribute Scale (MMAS) assessed over a 2-year period and then again at 5 years. Secondary outcomes included general quality of life (QoL), sexual activity, surgical intervention and safety. Data were analysed using iterative constant comparison. A state transition model-based cost-utility analysis was undertaken alongside the randomised trial. Quality-adjusted life-years (QALYs) were derived from the European Quality of Life-5 Dimensions (EQ-5D) and the Short Form questionnaire-6 Dimensions (SF-6D). The intention-to-treat analyses were reported as cost per QALY gained. Uncertainty was explored by conducting both deterministic and probabilistic sensitivity analyses. RESULTS: The MMAS total scores improved significantly in both groups at all time points, but were significantly greater for the LNG-IUS than for usual treatment [mean difference over 2 years was 13.4 points, 95% confidence interval (CI) 9.9 to 16.9 points; p < 0.001]. However, this difference between groups was reduced and no longer significant by 5 years (mean difference in scores 3.9 points, 95% CI -0.6 to 8.3 points; p = 0.09). By 5 years, only 47% of women had a LNG-IUS in place and 15% were still taking usual medical treatment. Five-year surgery rates were low, at 20%, and were similar, irrespective of initial treatments. There were no significant differences in serious adverse events between groups. Using the EQ-5D, at 2 years, the relative cost-effectiveness of the LNG-IUS compared with usual medical treatment was £1600 per QALY, which by 5 years was reduced to £114 per QALY. Using the SF-6D, usual medical treatment dominates the LNG-IUS. The qualitative findings show that women's experiences and expectations of medical treatments for HMB vary considerably and change over time. Women had high expectations of a prompt effect from medical treatments. CONCLUSIONS: The LNG-IUS, compared with usual medical therapies, resulted in greater improvement over 2 years in women's assessments of the effect of HMB on their daily routine, including work, social and family life, and psychological and physical well-being. At 5 years, the differences were no longer significant. A similar low proportion of women required surgical intervention in both groups. The LNG-IUS is cost-effective in both the short and medium term, using the method generally recommended by the National Institute for Health and Care Excellence. Using the alternative measures to value QoL will have a considerable impact on cost-effectiveness decisions. It will be important to explore the clinical and health-care trajectories of the ECLIPSE (clinical effectiveness and cost-effectiveness of levonorgestrel-releasing intrauterine system in primary care against standard treatment for menorrhagia) trial participants to 10 years, by which time half of the cohort will have reached menopause. TRIAL REGISTRATION: Current Controlled Trials ISRCTN86566246. FUNDING: This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 19, No. 88. See the NIHR Journals Library website for further project information.