Production Cost Research Papers - Academia.edu (original) (raw)

Purpose -The purpose of this paper is to analyse the current status of the poultry meat supply chain. Design/methodology/approach -The research included a literature review and evaluation of financial performance data to determine the market conditions that have impacted on both individual organisations and supply chains. Findings -The financial data has demonstrated, for the transnational corporations (TNC) studied, a significant reduction in financial performance over the last 12 months. This is due in part to the influence of avian influenza, but also to the over supply of poultry meat and increased production costs. The ongoing management of risk within this context needs to not only address traditional risk factors, but also in publicly traded organisations address the effective management of investment risk to ensure continued shareholder confidence and organisational viability. Originality/value -This research is of academic value and of value to those working in the food supply chain.

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- Supply Chain, Multidisciplinary, Literature Review, Avian Influenza

Fruit thinning has been practised for thousand of years, and serves a number of purposes. Too many fruits per tree can result in small fruit size and poor quality, breakage of limbs, exhaustion of tree reserves, and can also partially o completely inhibit bud initiation. Hand thinning of the peaches is the most common thinning practice adopted, but it is

- by Belén Diezma
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- Profitability, Laboratory experiment, Field Experiment, Low Power

Cellulose nanofibers with a size range of 5–100 nm have the potential to be a low cost renewable material that has application in a range of products. However, current chemical methods to produce crystalline nanofibers suffer from low yields and high chemical costs, while mechanical methods require high energy costs. Methods to lower the energy costs of the mechanical methods have not been well documented in the literature. A bleached softwood kraft pulp was processed using a mechanical dispersion mill and a homogenizer to produce cellulose nanofibers. Two different commercial enzymes were used to pretreat the wood fibers before the mechanical treatments. The resulting nanofibers were characterized by light microscopy, atomic force microscopy, and inverse gas chromatography. Results indicate that the dispersion mill does not affect the overall pulp fiber fibrillation, but does help prepare the sample for the homogenizer. Most fibrillation occurs after three passes through the homogenizer. The enzyme pretreatment has little effect on the size of the fibers, but does allow for higher solids to pass through the homogenizer without clogging. The dispersion component of surface energy of the resulting nanofibrils is impacted by the type of enzyme used. The measurement of acid–base properties proved to be challenging using current IGC experimental protocols.

- by Nazia Siddiqui
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- Mechanical Engineering, Chemical Engineering, Technology, Biotechnology

A total 67 strains were isolated from five different stations of Aksu River. Total aerobic bacteria number in the river was determined as 2 x 10 7 CFU/mL and fecal coliforms were determined >1100 MPN/100 mL. Strains of Enterobacteriaceae (66 isolates), representative of the human and animal commensal flora, and Pseudomonas sp. (1 isolate) were selected for antibiotic susceptibility testing. Among the isolates, 67,2% were Escherichia coli, 29,8% Klebsiella spp., 1,5% Citrobacter spp., and 1,5% Pseudomonas spp. Eleven antibiotics (Meropenem, Cefoxitin, Ceftazidime, Ceftriaxone, Imipenem, Sulbactam/Cefoperazone, Cefazoline, Cefotaxime, Aztreonam, Ampicillin/Sulbactam, Penicillin G) were used for determination of antibiotic resistance of isolates. Multiple antibiotic resistances were determined in 27 isolates (40%) and they were resistant to five or over antibiotics and 49,3% of the isolates were found to be β-lactamase producing.

- by Hoang Nguyen
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- Zoology, Public Health, Aquaculture, Antibiotic Resistance

This paper aims at illustrating the compared results of the application of two different approaches-respectively parametric and artificial neural network techniques-for the estimation of the unitary manufacturing costs of a new type of brake disks produced by an Italian manufacturing firm. The results seem to confirm the validity of the neural network theory in this application field, but not a clear superiority with respect to the more ''traditional'' parametric approach: in particular, the ANN seems to be characterised by a better trade-off between precision and cost of development, while a critical point-especially in the specific application context-is represented by the reduced possibility of interpreting output data (which is critical for the ''optimisation'' of design solutions during the new product development process). r

- by sergio cavalieri
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- Production, New Product Development, Industrial Engineering, Automotive Industry

We deal with the problem of making capital investments in machines for manufacturing a product. Opportunities for investment occur over time, every such option consists of a capital cost for a new machine and a resulting productivity gain, i.e., a lower production cost for one unit of product. The goal is that of minimizing the total production and capital costs when future demand for the product being produced and investment opportunities are unknown. This can be viewed as a generalization of the ski-rental problem and related to the mortgage problem 3].

- by Yossi Azar
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- Multidisciplinary, Capital Investment, Lower Bound, Production Cost

Multiplant monopoly models generally assume that firm demand is unaffected by the number of plants established. This assumption is inappropriate when transportation costs are significant. Because of this, a multiplant spatial monopolist may choose to operate on the downsloping, constant, or upsloping segment of plant average production cost curves, depending upon the impact of additional plants on cost levels. However, such a monopolist will choose a long-run firm size which is associated with increasing firm level average costs as long as economic profits are available. Long-run average costs are minimized if the monopolist just breaks even.

- by Bruce Benson
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- Econometrics, Urban And Regional Planning, Applied Economics, Production Cost

Companies strive to position themselves to maximize the value they add to the supply chains in which they are embedded. This raises strategic questions such as: Which durable resources should be developed to enhance current core competencies? Which activities should be externalized and to which potential partner should they be given? Which internal activities should be preserved and developed? How should the resources of the enterprise be allocated to activities? The aim of this paper is to propose a mathematical programming model of the extended enterprise which can be used to investigate this type of strategic networking issues. A number of general network modeling constructs are ®rst proposed. A model to optimize the supply chain structure under speci®c assumptions on the nature of production, cost and value functions in typical production/distribution companies is then derived. A heuristic to obtain solutions from the model is also presented. Finally, an example based on a refrigerator company is used to illustrate the usefulness of the approach.

- by سالم ألاكحل
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- Engineering, Computer Science, Mathematical Programming, Theory of the Firm

Spirulina platensis was cultivated, in comparative studies, using several sources of nitrogen. The standard source used (sodium nitrate) was the same as that used in the synthetic medium Zarrouk, whereas the alternative nitrogen sources... more

- by Lucielen Santos
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- Technology, Comparative Study, Biological Sciences, World

Cotton farmers in many developing countries are facing decreasing marginal returns due to stagnating yields and high input costs. Conversion to organic management could offer an alternative. In a two year comparative study in central... more

- by Frank Eyhorn
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- Organic agriculture, Comparative Study, Organic Farming, Developing Country

1 Offshore-outsourced software development is gaining popularity because companies are continuously forced to reduce production costs while keeping sustainable competitive strength. However, this trend of software development increases projects' complexity and brings up risks to the overall project environment. Therefore, risks of offshore software development require to be managed as early as possible for a successful project. This paper considers a risk management model from a holistic perspective to manage offshore software development risk, integrated into early stages of development. The approach effectively identifies and specifies the goals of a project and the related risk factors. This is done at the basis of selected software development components within the running project. We show how to trace and control these risks already during early requirements engineering activities. The model at hand is implemented into an ongoing offshore software development project to (1) identify goals and risk factors from the local context and finally (2) to determine its applicability of the approach in offshore software development projects from a vendor's perspective.

- by Shareeful Islam
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- Software Development, Risk Management, Modeling Language, Requirement Engineering

The non-homothetic production cost structure in Norwegian private dentistry involves more than two factor inputs. Consequently, this paper implements-separately for solo and group practices-three conceptually different measures of factor substitutions to infer the precise nature of input associations using translog cost model estimates based on 1993 data. We calculate own- and cross-price elasticities of factor demands, pairwise elasticities of substitution and their approximate S.E.s. We find that: (1) dentists and dental assistants cannot be consistently aggregated as one homogeneous labour input; (2) input demands are inelastic; (3) the theoretically restrictive Allen-Uzawa and the less restrictive shadow and Morishima elasticities of substitution are not equivalent; (4) dentists and auxiliary dental personnel relate as significant substitutes in solo practices and as significant complements in group practices; (5) 'supplies' (e.g., dental materials) in the aggregate are substitutes for the two types of dentistry labour; and (6) there appears to be a wider scope for factor substitutions in group rather than solo practices. Due to inelastic factor demands, opportunities for cost controls are limited despite some tendencies for factor interchange. Finally, future researchers of production costs involving more than two inputs should investigate the less restrictive, alternative measures of factor substitutions.

- by Albert Okunade
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- Economics, Health Economics, Health Policy, Price Elasticity

As markets expand due to globalization, chemical manufacturers are faced with the challenge of meeting the rapidly growing global demand for production at a time when production costs are increasing due to rising feedstock prices. One way for chemical manufacturers to ensure profitability in the current environment is to foster innovation through the use of advanced modeling techniques. The Chemical Industry Vision2020 Technology Partnership 1 highlights opportunities to address several challenges in the chemical industry through shared pre-competitive research and development activities in many technology areas, and offers a special focus on high-end modeling. In this paper we examine the available technologies in the chemical industry and highlight several areas where major advances have been achieved through innovation fostered by advanced modeling of industrial processes.

In this paper, an advanced control system for the optimal operation and management of isolated power systems with increased renewable power integration is presented. The control system minimises the production costs through on-line optimal scheduling of the power units, taking into account short-term forecasts of the load and the renewable resources. The power system security is supervised via on-line security assessment modules, which emulate the power system frequency changes caused by pre-selected disturbances. For each of the above functions, a number of techniques have been applied, both conventional and AI based. The system has been installed in the dispatch center of Crete since June 1999, and is under evaluation

- by Johnny Lopes
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- Power System, Control system, Power System Security, Power Engineering

The overall objective of this work is to identify the effects of climate change on the Norwegian energy system towards 2050. Changes in the future wind-and hydro-power resource potential, and changes in the heating and cooling demand are analysed to map the effects of climate change. The impact of climate change is evaluated with an energy system model, the MARKAL Norway model, to analyse the future cost optimal energy system. Ten climate experiments, based on five different global models and six emission scenarios, are used to cover the range of possible future climate scenarios and of these three experiments are used for detailed analyses. This study indicate that in Norway, climate change will reduce the heating demand, increase the cooling demand, have a limited impact on the wind power potential, and increase the hydro-power potential. The reduction of heating demand will be significantly higher than the increase of cooling demand, and thus the possible total direct consequence of climate change will be reduced energy system costs and lower electricity production costs. The investments in offshore wind and tidal power will be reduced and electric based vehicles will be profitable earlier.

- by Eva Rosenberg
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- Climate Change, Energy Policy, Multidisciplinary, Wind Power

The continuous high demand of water resources for agricultural uses in Jordan is leading to a water crisis. A possible partial solution may be to import food which requires large amounts of water to grow instead of cultivating high water consuming crops. Crops such as banana and citrus cause a huge virtual water loss, which can be reduced by cultivating other less water-demanding crops. This paper focuses on analyzing the economic value of cultivating tree fruit from a virtual water perspective. The virtual water calculations in this study depend on the average rainfall, water quota, and the crops' water requirements (CWR). The gross profit to the water use ratio showed that banana has the lowest value 0.085 JD/m 3 , while lemon has the highest value 1.65 JD/m 3 . The calculations show that the average embedded water in fruits varies from about 470 m 3 /ton for grapes to about 2,500 m 3 /ton for dates. Banana and citrus plantations consume about 21 and 71 million cubic meters (MCM) annually, respectively, which represent about 85% of the total water consumption in fruit tree plantation. The virtual water flow estimation embedded in fruits shows that Jordan imports about 77 MCM per year. However it exports about 29 MCM per year. The results were analyzed from an integrated water resources management (IWRM) perspective. The analysis shows that a way to recover some of the water costs involved in, e.g., banana production would be

- by Hartmut Gaese and +1
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- Water, Water resources, Consumption, Water Resources Management

This paper is a follow-up of preViouS work on optimal spotpricing of electricity [3]. The issue of long-term planning in the electric utility industry as it relates to the adoption of socially optimal spot pricing is considered. Optimal investment conditions are derived and an algorithm is developed which allows integration of these conditions into long-term planning. The proposed algorithm is an extensionl of Bootht-aleriaux probabilistic production costingand thus exhibits high computational efficiency. It provides the building block forincorporating spot pricing into a number of mathematical programminaf methodologies currently used in generation expansion planning studies. The algorithm's usefulness to produce optimal spot price forecasts that may induce socially efficient investments in non-utility-owned generation and to facilitate empirical studies on the income distributional impact of spot price implementation is also discussed.

The imminent decline of the world's oil production, its high market prices and environmental impacts have made the production of biofuels to reach unprecedent volumes over the last 10 years. This is why there have been intense debates among international organizations and political leaders in order to discuss the impacts of the biofuel use intensification.Besides assessing the causes of the rise in the demand and production of biofuels, this paper also shows the state of the art of their world's current production. It is also discussed different vegetable raw materials sources and technological paths to produce biofuels, as well as issues regarding production cost and the relation of their economic feasibility with oil international prices. The environmental impacts of programs that encourage biofuel production, farmland land requirements and the impacts on food production are also discussed, considering the life cycle analysis (LCA) as a tool.It is concluded that the rise...

In the last years, multi-agent systems (MAS) have proved more and more successful. The need of a quality software engineering approach to their design arises together with the need of new methodological ways to address important issues such as ontology representation, security concerns and production costs. The introduction of an extensive pattern reuse practice can be determinant in cutting down the time and cost of developing these systems. Patterns can be extremely successful with MAS (even more than with objectoriented systems) because the great encapsulation of agents allows an easier identification and disposition of reusable parts. In this paper we discuss our approach to the pattern reuse that is a phase of a more comprehensive approach to agent-oriented software design.

Dramatic shortcomings of mill liner designs, especially of large SAG mills,-such as rapid failure and even mill shell damage arising from impacting of the charge directly on the liner, and unsuitable spacing of lifter bars yielding unfavourable compromises between lifter bar height and liner life-have highlighted the significance of correct mill liner selection. Liners protect the mill shell from wear and transfer energy to the grinding charge, and a careful balance is required to optimise these conflicting requirements. This review serves to highlight these problems and how they can be tackled in a logical and often inexpensive manner by considering charge trajectories and liner spacing criteria, in conjunction with liner wear monitoring. An overview is given of the principal types and materials of construction of mill liners. Examples of good and bad liner design are given, followed by a rigorous approach to liner design based on the best technology available, combined with experience and logical engineering thinking. Methods of monitoring the progressive wear of liners, and relating this to the performance of the mill are presented. The value of wear monitoring in ongoing liner optimisation and cost saving, through balancing the lives of the lifters and shell plates, and providing reliable comparative data for testing different liner materials and designs, is explained. Wear testing techniques and their drawbacks and limitations are discussed, along with new tests under development. The contribution of advanced computation techniques, such as the Discrete Element Method (DEM), to predicting the wear profiles of liners, and integrating this information into optimising the overall performance of the mill from a production and cost perspective, are considered in some detail. This takes into account the change of the charge trajectories, energy transfer, and milling efficiency, as the mill liner wears and the profile changes. It is hoped that this review will better arm mill operators to select suitable mill liners, with a view to decreasing production costs while maintaining mill performance near optimal levels.

- by Peter Radziszewski
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- Discrete Element Method, Cost Saving, Energy Transfer, Production Cost

Industrial automation is useful to reduce production costs and improve product quality. The wine industry has been increasingly adopting industrial automation seeking these objectives. In Chile, wineries have been lagging behind in embracing new technologies to control the fermentation process. In most cases, enologists decide control actions (cooling, heating, pumping over) based on off line periodic measurements. In this work we explore the applicability of ultrasound to measure the sugar and alcohol concentrations of hydroalcoholic solutions mimicking fermenting musts. Additionally, implementation issues such as the attenuation effect of bubbles and tank curvature are analyzed. We show that working at two sufficiently distinct frequencies, we can measure sugar and alcohol content simultaneously. Measurement resolution achieved for the wave time of travel translates to a better than 0.02% for both concentrations, depending on the container size.

- by Yonny Vargas
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- Environmental Science, Industrial Automation, Ultrasound, New Technology

Filamentous fungi Trichoderma reesei are considered to be one of the most efficient hyper producers of cellulase that is used in industry. Cellulase production by T. reesei was carried out using high concentration of cellulose to substitute glucose with the aim to improve cellulase production while trying to reduce production costs. The experiments were conducted separately as fed batch growth with T. reesei cultured using four media in a 7 L stirred tank bioreactor. A mixture of lactose and lactobionic acid was added into the bioreactor as cellulase inducers. The use of a cellulose-yeast extract culture medium yielded the highest enzyme and cell production with a volumetric enzyme activity of 69.8 U L −1 h −1 , a filter paper activity of 5.02 U mL −1 , a CMCase activity of 4.2 U mL −1 , and a fungal biomass of 14.7 g L −1 . The biomass concentration as a function of time was constant with relatively rapid, early growth on easily metabolized growth medium components (yeast extract), followed by a second slower growth phase due to hydrolysis of cellulose, which follow cellulase concentration augmentation. The costs to produce 1 L of production medium in laboratory-scale experiments were calculated to compare the tested media.

- by Aftab Ahamed
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- Chemical Engineering, Production, Biochemical Engineering, Culture

Assessment of the economic value of software systems is useful in contexts such as capitalization on the balance sheet and due diligence prior to acquisition. Current accounting practice in determining software value is based on the cost spent in software development. This approach fails to account for the efficiency with which software has been produced or the quality of the product. This paper proposes three alternative models for determining the production value of software, based on the notions of technical debt and interest. We applied the models to 367 proprietary systems developed by a range of different organisations using a range of different programming languages. We present the valuation results and discuss the weaknesses and strengths of the models.

- by ariadi nugroho
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- Programming Languages, Production, Software Development, Cost Accounting

Concentrating Solar Power (CSP) plants are a promising technology of renewable energy production, as witnessed by the increasing public and private investments during the last decade. The assessment of the associated risks of business interruption (loss of production) and loss of assets due to the occurrence of undesired internal or external events, such as failures of components, unfavorable environmental conditions, etc., brings added values by informing design modifications and contributing to production assurance, for rational Company investments in these environmentally sustainable power plants. This work presents and applies a methodology for assessing the risks associated to a CSP of innovative design. The methodology is derived from traditional system risk analysis, specifically focused only on the economic consequences of the internal events of failure behavior of components. The innovation in the design considered is particularly aimed at augmenting the CSP intrinsic capability of being equipped with thermal storage systems by the introduction of a molten salt mixture as heat transfer fluid. This technology presents evident advantages in terms of system simplification and reduction of production costs but on the other hand introduces a risk factor with regards to the solidification of the salt mixture that occurs at about 240 C.

- by Michele Compare
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- Mechanical Engineering, Design, Renewable Energy, Methodology

For preparation of a proper offer in tool-making industry the most frequently the values of total cost for manufacture are needed. Because of lack of time for making a detailed analysis the total costs of tool manufacture are predicted by the expert on the basis of the experience gathered during several years of work in this area. In our work we conceived an intelligent system for predicting of total cost of the tool manufacture. The system is based on the concept of case-based reasoning; on the basis of target and source cases the system prepares the prediction of cost. The target case is the CAD-model in whose certain production costs we are interested, whereas the source cases are the CAD-model of products, for which the tools had already been made, and the relevant total costs are known. The system first abstracts from CAD-models the geometrical features, and then it calculates the similarities between the source cases and target case. Then the most similar cases are used for preparation of prediction by genetic programming method. The genetic programming method provides the model connecting the individual geometrical features with total costs searched for.

- by Igor Drstvensek
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- Engineering, Materials Engineering, Mechanical Engineering, Genetic Programming

Uncooled IR sensors have become popular recently for imaging applications thanks to low cost, advances in MEMS and micromachining, as well as high reliability, as compared to their photon detectors counterparts, which require cooling. Several implementations of uncooled infrared detectors have been studied and implemented, such as microbolometer , pyroelectric [5], thermopile [6-8] and diode . More recently, significant effort is invested to achieve compatibility with standard CMOS technologies, enabling low-cost production of large arrays of IR detectors for various applications, like driver's night vision enhancement and security.

- by Sara Stolyarova
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- Theory and Practice, High performance, Monolithic Integration, Production Cost

The user has requested enhancement of the downloaded file. All in-text references underlined in blue are added to the original document and are linked to publications on ResearchGate, letting you access and read them immediately. This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.

Since the 1980s, Mexico became an attractive location for global automobile assemblers. Geographical proximity and low production costs were associated with high productivity. As this industry became highly concentrated, benefits for the host localities turned into a controversial issue. Taking this controversy as a background, a case study was designed to gather evidence from new local knowledge-intensive firms within the supplier network in the automotive cluster led by Ford Motor Company in Hermosillo, Mexico. Our findings revealed that a new trend of knowledge-intensive small local companies emerged, providing higher value services and playing more important roles in the supply chain.

- by Jorge Alonso Estrada
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- Economics, Automotive Industry, Case Study, Global value chain

We consider a three-tier supply chain consisting of an original equipment manufacturer (OEM), a contract manufacturer (CM) and a supplier. We analyze and compare three outsourcing structures that are currently implemented by top-tier OEMs: (1) inhouse consignment, under which the OEM signs independent contracts with the CM and the supplier; (2) turnkey with integration, under which the OEM contracts with an alliance of the CM and the supplier; and (3) turnkey, under which the OEM contracts with the CM, and the CM then subcontracts with the supplier. The OEM is a Stackelberg leader who decides how much of the end product to produce. All parties use take-it-or-leave-it wholesaleprice contracts. Both the CM and the supplier have private information about their own production costs. The OEM has prior information about these costs, but this prior information depends on the specific outsourcing structure. Each party's optimal decision is characterized. We then compare each party's profits across the three outsourcing structures and identify which benefits and when.

- by Pengfei Guo
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- Outsourcing, Supply Chain, Multidisciplinary, Information Flow
- by Lars Waldheim
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- Engineering, Technology, Biomass, GAS TURBINE

The profitability of rearing the rheophilic cyprinid fish species asp, Aspius aspius (L.), and ide, Leuciscus idus (L.), in two independent closed recirculating systems was evaluated. The fish were fed live Artemia nauplii exclusively. The rearing of both species was profitable and the financial risk was relatively low. From the point of view of profitability, the purchase price of stocking material was the most significant factor. The price of juvenile asp was 2.5 times higher than that of ide. Rearing larval asp was the most profitable venture. systems is improving continually rendering this method an increasingly serious alternative especially for rearing the youngest varieties of stocking material.

- by Dariusz Kucharczyk and +1
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- Profitability, Fisheries Sciences, Financial Risk, Point of View

Recurring cost has become a critical driver in the design of helicopter airframes, and although composite materials have become widely used in aircraft structures, the hand lay-up manufacturing process in many cases prevents these applications from being cost-effective. Automated manufacturing technologies promise not only reduced production costs but also higher quality, repeatable parts. The introduction of existing automated manufacturing techniques

- by Robert Fews and +1
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- Engineering Design, Multidisciplinary, Quality Control, Cost effectiveness

To achieve high productivity in a flexible manufacturing system (FMS), an efficient layout arrangement and material flow path design are important due to the large percentage of product cost that is related to material handling. The layout design problem addressed in this paper has departments with fixed shapes and pick-up/drop-off points. It is an open-field type layout with single-loop directed flow path. A two-step heuristic is proposed to solve the problem. It first solves a traditional block layout with directed-loop flow path to minimize material handling costs by using a combined spacefilling curve and simulated annealing algorithm. The second step of the proposed methodology uses the resulting flow sequence and relative positioning information from the first step as input to solve the detailed FMS layout, which includes the spatial coordinates and orientation of each FMS cell. This detailed FMS layout problem is formulated and solved as a mixed integer program. Empirical illustrations show promising results for the proposed methodology in solving real-world type problems.

- by Taho Yang
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- Simulated Annealing, Multidisciplinary, Open Field, Flow Pattern

The building construction firms have been improved the quality of its activities due to the high market competition and the consumer's demands. In this situation, the design of the different parts of the building, including the product and the production process definitions, is fundamental to improve the costs and the building performance. The external rendering is one of the parts

- by Débora De Paula
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- Profitability, Production Cost

Implementing monolithic DC-DC converters for low power portable applications with a standard low voltage CMOS technology leads to lower production costs and higher reliability. Moreover, it allows miniaturization by the integration of two units in the same die: the power management unit that regulates the supply voltage for the second unit, a dedicated signal processor, that performs the functions required. This paper presents original techniques that limit spikes in the internal supply voltage on a monolithic DC-DC converter, extending the use of the same technology for both units. These spikes are mainly caused by fast current variations in the path connecting the external power supply to the internal pads of the converter power block. This path includes two parasitic inductances inbuilt in bond wires and in package pins. Although these parasitic inductances present relative low values when compared with the typical external inductances of DC-DC converters, their effects can not be neglected when switching high currents at high switching frequency. The associated overvoltage frequently causes destruction, reliability problems and/or control malfunction. Different spike reduction techniques are presented and compared. The proposed techniques were used in the design of the gate driver of a DC-DC converter included in a power management unit implemented in a standard 0.35 mu m CMOS technology. Addresses: [Rocha, Jose] IPL,

- by Gabriel cruz santos cs
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- Signal Processing, Production, Power Management, Energy Management

This paper addresses a real-life 1.5D cutting stock problem, which arises in a make-to-order plastic company. The problem is to choose a subset from the set of stock rectangles to be used for cutting into a number of smaller rectangular pieces so as to minimize total production cost and meet orders. The total production cost includes not only material wastage, as in traditional cutting stock problems, but also production time. A variety of factors are taken into account, like cutter knife changes, machine restrictions, due dates and other work in progress limitations. These restrictions make the combinatorial structure of the problem more complex. As a result, existing algorithms and mathematical models are no longer appropriate. Thus we developed a new 1.5D cutting stock model with multiple objectives and multi-constraints and solve this problem in an incomplete enumerative way. The computational results show that the solution procedure is easy to implement and works very well. Ó 2005 Published by Elsevier B.V.

- by Chengbin Chu
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- Multidisciplinary, Work in Progress, Mathematical Model, Cutting Stock Problem

The application of waste frying oil (WFO) mixed with rapeseed oil as a feedstock for the effective production of fatty acid methyl esters (FAME) in a lipase-catalyzed process was investigated. The response surface methodology (RSM) was used to optimize the interaction of four variables: the percentage of WFO in the mixed feedstock, the methanol-to-oil ratio, the dosage of Novozym 435 as a catalyst and the temperature. Furthermore, the addition of methanol to the reaction mixture in a second step after 8 h was shown to effectively diminish enzyme inhibition. Using this technique, the model predicted the optimal conditions that would reach 100% FAME, including a methanol-to-oil molar ratio of 3.8:1, 100% (wt) WFO, 15% (wt) Novozym 435 and incubation at 44.5°C for 12 h with agitation at 200 rpm, and verification experiments confirmed the validity of the model. According to the model, the addition of WFO increased FAME production yield, which is largely due to its higher contents of monoacylglycerols, diacylglycerols and free fatty acids (in comparison to rapeseed oil), which are more available substrates for the enzymatic catalysis. Therefore, the replacement of rapeseed oil with WFO in Novozym 435-catalyzed processes could diminish biodiesel production costs since it is a less expensive feedstock that increases the production yield and could be a potential alternative for FAME production on an industrial scale.

- by Hermann Heipieper and +1
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- Engineering, Technology, Production, Catalysis

Evidence about the total cost of health, absence, short-term disability, and productivity losses was synthesized for 10 health conditions. Cost estimates from a large medical/absence database were combined with findings from several published productivity surveys. Ranges of condition prevalence and associated absenteeism and presenteeism (on-thejob-productivity) losses were used to estimate condition-related costs. Based on average impairment and prevalence estimates, the overall economic burden of illness was highest for hypertension ($392 per eligible employee per year), heart disease ($368), depression and other mental illnesses ($348), and arthritis ($327). Presenteeism costs were higher than medical costs in most cases, and represented 18% to 60% of all costs for the 10 conditions. Caution is advised when interpreting any particular source of data, and the need for standardization in future research is noted. (J Occup Environ Med. 2004;46: 398 -412)

- by Ronald J Ozminkowski
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- Nursing, Epidemiology, Mental Health, Occupational Health

Oxidoreductases are widely used in different branches of industry (particularly, in pharma ceutical) and analytical biotechnology. To optimize the use and to reduce production cost of a target product, the properties of a biocatalyst should be modified to meet requirements of a specific process or method of analysis. Problem of creation of biocatalysts with prescribed properties includes complex set of R&D such as an engineering of enzyme properties, con struction of recombinant strains overproducing the target protein, development of a large scale downstream process and preparation of a working form of a biocatalysts. In the present work, the basic features and practical examples of such an over all approach are considered for formate dehydrogenase and D amino acid oxidase.

- by V. Tishkov
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- Enzyme, CHEMICAL SCIENCES, Large Scale, Production Cost

Unfettered nationwide bank branching raises the issue of whether consolidation of banksÕ``back-oce'' operations, such as their payment processing, reduces operating costs. Whether centralized processing of payments reduces costs depends on the size and range of scale economies, the relative prices of data processing and telecommunication inputs, and changes in technology in addition to the number of sites operated. While consolidating payment operations into fewer sites may reduce average data processing costs, those cost savings may be more than oset by associated increases in telecommunications expenses. To investigate the potential eects of consolidation on future banking operations, we look at the experience of the Federal Reserve in consolidating its Fedwire electronic funds transfer operation over 1979 to 1996. Previous research suggested that scale economies in Fedwire payment processing were minimal and that the observed declines in average Fedwire production costs were largely attributable to technical advance. Our estimates suggest more nearly the opposite. We ®nd that the Fedwire funds transfer operation exhibited large scale economies but little technical advance beyond that already embodied in the technology-adjusted input prices of data 0378-4266/99/$ ± see front matter Ó 1999 Elsevier Science B.V. All rights reserved. PII: S 0 3 7 8 -4 2 6 6 ( 9 8 ) 0 0 1 0 8 -3 processing and telecommunication inputs. We also ®nd that the consolidation of Fedwire into fewer oces contributed around one-fourth of the overall reduction in Fedwire average cost. Ó

- by James A Wilcox
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- Applied Mathematics, Scale Economies, Technical Change, Federal Reserve

Balancing assembly lines is a crucial task for manufacturing companies in order to improve productivity and minimize production costs. Despite some progress in exact methods to solve large scale problems, softwares implementing simple heuristics are still the most commonly used tools in industry. Some metaheuristics have also been proposed and shown to improve on classical heuristics but, to our knowledge, no computational experiments have been performed on real industrial applications to clearly assess their performance as well as their flexibility. Here we present a new tabu search algorithm and discuss its differences with respect to those in the literature. We then evaluate its performance on the Type I assembly line balancing problem. Finally, we test our algorithm on a real industrial data set involving 162 tasks, 264 precedence constraints, and where the assembly is carried out on a sequential line with workstations located on both sides of the conveyor, with two possible conveyor heights and no re-positioning of the product. We discuss the flexibility of the metaheuristic and its ability to solve real industrial cases.

- by Angel Ruiz
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- Tabu Search, Multidisciplinary, Assembly line balancing, Industrial Application
- by George Torrance
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- Human Geography, Health Care, Sensitivity Analysis, Health Services

We develop a model to analyze optimal product-costing and pricing decisions in a dynamic information environment under long-term-capacity commitment. The arrival of new information about demand and cost parameters each period makes the problem complex. The optimal prices and capacity choices in our model cannot be decoupled as in Banker and Hughes' (1994) single-period model. The optimal prices are based on product costs that are adjusted each period to reflect changes in expected variable costs as well as utilization of fixed activity resources. The charge for each fixed resource is monotonically increasing in the expected demand for that resource in each state given the optimal capacity choice. The average optimal prices across periods and states are similar to Banker and Hughes' (1994) benchmark prices. Finally, we investigate a two-period version of the model to explore the optimality of carrying idle capacity. The optimal product-cost charge for fixed capacity is strict...

- by Iny Hwang
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- Management Accounting, Production Cost
- by Brack Hale
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- Energy Policy, Waste Management, Solid Waste Management, Multidisciplinary

O trabalho foi conduzido em povoamentos de eucalipto de uma empresa florestal do Estado de Goiás, com o objetivo de avaliar técnica e economicamente um sistema de colheita florestal de árvores inteiras composto de "feller-buncher", "skidder" e garra traçadora. Foi realizado um estudo de tempos e movimentos e determinados os custos operacionais e de produção das máquinas. Para avaliar esses valores de produtividade do "feller-buncher" e da garra traçadora, foi empregado um delineamento estatístico inteiramente casualizado com seis repetições, em esquema de parcelas subdivididas. Adotaram-se como parcelas as operações que compõem o ciclo operacional das máquinas e como subparcelas, os níveis de produtividade de floresta de 100, 200 e 300 m³ ha -1 . Os valores foram submetidos à análise de variância e ao teste de Tukey a 5% de probabilidade. Para avaliar o efeito dos tempos consumidos nas operações do ciclo operacional do "skidder" nas produtividades de floresta de 100, 200 e 300 m³ ha -1 e nas distâncias de arraste de 100, 200 e 300 m, assim como avaliar suas interações quando significativas, utilizou-se um delineamento estatístico de blocos casualizados, em esquema fatorial 6x3x3, sendo seis operações, três produtividades e três distâncias de arraste, com quatro repetições. Os valores foram submetidos à análise de variância e ao teste de Tukey a 5% de probabilidade. Concluiu-se que o "feller-buncher" registrou o maior custo de produção dentro do sistema, obtendo melhor capacidade efetiva de trabalho nas áreas de maior produtividade. O "skidder" também teve seu melhor desempenho no talhão de 300 m³ ha -1 na distância até 200 m. A garra traçadora apresentou custo de 0.97, 0.75 e 0.63 US$ m -3 para as produtividades de 100, 200 e 300 m³ ha -1 , respectivamente.

- by Amanda Bernardes and +1
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- Technical Analysis, Economic analysis, Analysis of Variance, Forest Harvesting

This paper discusses an approach to solve the joint replenishment problem in a production environment with variable production cost. These variable production costs occur due to economies of scale in production. Under this environment, the model leads to a global optimization problem, which is investigated by using some standard results from convex analysis. Consequently, an effective and exact solution procedure is proposed. The proposed procedure is guaranteed to return a solution with a predetermined quality in terms of the objective function value. A computational study is provided to illustrate the performance of the proposed solution procedure with respect to the running time.

- by Hans J B G Frenk
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- Multidisciplinary, Global Optimization, Convex Analysis, Convex Programming

interdependence and mutual interest have often brought the two countries together in the international arena, differences in their political systems and cultural backgrounds and a historic lack of mutual trust have often generated political tensions. It should be noted at the outset that many of the issues that have motivated US economic sanctions against China are politically sensitive and highly controversial. China has consistently denied the allegations on which US sanctions have been based and disputed the rationale for the sanctions. Despite claims in recent years that the two countries are committed to building a constructive and strategic partnership, US economic sanctions against China are likely to persist. This is due to the delicate and fragile nature of their relationship. As Ross (1998) points out, instability arises from such factors as historical legacies, elite and societal ideological differences, interest groups, and domestic economic and political interests. Thus, US economic sanctions against China pose an issue of long-term relevance for both policy and international business research. This study focuses on the economic and business impact of US sanctions against China. The consequences of sanctions are evaluated from both countries' perspectives at both the macro-and the microeconomic levels. At the macroeconomic level, we examine how sanctions have affected trade flows (both exports and imports), investments, employment and overall economic development. At the microeconomic level, we highlight the impact on selected industry sectors. 2. US ECONOMIC SANCTIONS AGAINST CHINA US economic sanctions against China can be divided into three major categories: (1) US laws and regulations that apply to China but are not exclusive to China; (2) Multilateral sanctions that the US leads or participates in that apply to China but are not exclusive to China; and (3) US sanctions imposed specifically on China, although such sanctions may not necessarily be unique for China. a. US Trade Laws and Regulations that Apply to Trade with China US trade laws and regulations that affect US-China trade the most are export controls. There are two principal statutes that govern US export controls pertaining to China today: (1) The Export Administration Act of 1979, as amended, which controls 'dual-use' items and is administered by the Department of Commerce-these items comprise what is often called the 'Commerce Control List', or CCL; (2) The Arms Export Control Act, which targets munitions items and is administered by the Department of State. These items constitute the 'US Munitions List', or USML. These two statutes govern exports of commercial US ECONOMIC SANCTIONS AGAINST CHINA 1049 © Blackwell Publishing Ltd 2004 communication satellites, high-performance computers, machine tools and other 'dual-use' or high-tech products. b. Multilateral Sanctions The United States has led and joined a number of multilateral arrangements to enforce a uniform export control policy (EAA, 1979). The Wassenaar Arrangement on Export Controls is one such example. Until its dissolution in March 1994, the Coordinating Committee on Multilateral Export Controls (COCOM) was the primary multinational export control organisation through which the United States and the other member countries controlled the export of items for security purposes. China was a COCOM-proscribed country among other Communist countries. In September 1996 COCOM was replaced by a new multinational organisation-the Wassenaar Arrangement on Export Controls for Conventional Arms and Dual-Use Goods and Technologies. The Wassenaar Arrangement maintains a control list of export items similar to the previous COCOM list as it existed in 1993 (US House of Representatives, 1999). Some items in the Wassenaar control list are included in the US Commerce Control List and the remainders are included in the US Munitions List. This agreement, in theory, obligates other member countries to impose the same export controls on China as the United States imposes.

- by John Forrer
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- Economic Growth, Technology transfer, Applied Economics, World Economy

The feasibility of microalgae production for biodiesel was discussed. Although algae are not yet produced at large scale for bulk applications, there are opportunities to develop this process in a sustainable way. It remains unlikely, however, that the process will be developed for biodiesel as the only end product from microalgae. In order to develop a more sustainable and economically feasible process, all biomass components (e.g. proteins, lipids, carbohydrates) should be used and therefore biorefi ning of microalgae is very important for the selective separation and use of the functional biomass components. If biorefi ning of microalgae is applied, lipids should be fractionated into lipids for biodiesel, lipids as a feedstock for the chemical industry and w -3 fatty acids, proteins and carbohydrates for food, feed and bulk chemicals, and the oxygen produced should be recovered also. If, in addition, production of algae is done on residual nutrient feedstocks and CO 2 , and production of microalgae is done on a large scale against low production costs, production of bulk chemicals and fuels from microalgae will become economically feasible.

- by R. Wijffels
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- Engineering, Mechanical Engineering, Chemical Engineering, Technology