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A batch size model developed for the therapeutic product problem has been instrumental in assisting the staff of a large general hospital to resolve problems associated with the transactional process of the preparation of intravenous medications for administration. The model is a variation of a basic profit maximisation model and is characterised by variable batch preparation cost, a variable planning period, fixed per unit base cost, and zero shortage costs since preparation of a new batch can take place without delay. The variable planning period is transformed into a fixed planning horizon which is at least several multiples of the planning period and is fixed. Development of the model is presented and illustrated with a hypothetical situation, followed by a real case — the determination of the optimal batch size for the intravenous drug, Cefazolin.

The purpose of this paper is to determine whether man-hour efficiency of picking is affected by the use of batch preparation, compared to preparation of one kit at a time. This paper focuses on small kit preparation areas.

This paper is based on two experiments that were performed at a vehicle assembly plant and then analysed quantitatively.

The results provide a strong indication of the advantages associated with batch preparation, in terms of man-hour efficiency.

The fact that the effects identified during the experiments are substantial, over 20 per cent reduction of average time per picked component in Experiment 1 and 7 per cent in Experiment 2, indicates that the option of batch picking holds potentials for large cost reduction and should be considered when kit preparation systems are designed.

Limited research has dealt with the design of kit preparation systems, thus leaving considerable knowledge gaps. Previous research dealing with batch picking focuses on other environments than kitting and on large picking areas where batching can reduce walking distances. In contrast, the current paper focuses on small picking areas, which are common in industrial kitting applications. This paper provides a considerable contribution by demonstrating improvements in time efficiency that batch preparation can offer to small picking areas in addition to larger areas. The discussion also provides a basis for future research, which could focus on aspects other than time efficiency, such as the quality of kit preparation, and variables that might moderate the effect of batching.

Much research has been reported on the possibilities of using various heuristic priority rules to sequence batches through a job shop. The SPT (Shortest Priority Time) heuristic, or modifications to it, has been proved useful in many studies. This paper reports on the results obtained when simulating the work flow through a real machine shop. The simulation model has been used to test the effect on well known priority rules of releasing batches into the shop in order of decreasing expected throughput time. The important effect of this “phased release” of batches was to increase the percentage of batches delivered in finished parts stores on time, particularly in the case where priority rules were in use which might otherwise have resulted in poor delivery. This has important repercussions for management because it implies that by “phased” release of batches in the manner discussed, a large proportion of batches will be delivered on time whatever priority rule is in operation in the shop.

Considers the resurgence in use of batch files due to the number of hard disk systems in operation, and the advantages batch files offer in additional software installation. Describes two batch file procedures, setting up a hard disk, and copying information into files. Surmises that use of batch files to automate setup and revision procedures is viable for library systems with a number of microcomputers.

To determine optimum design and operation parameters for ternary batch distillation under fixed product demand.

In this study, two different scenarios are considered. In the first scenario, the column specification (in terms of number of plates and vapour load) and product demand are given and the optimum operation policy is determined. In the second scenario, with a fixed batch time and product demand, the optimal design (in terms of number of plates and vapour load) and operation policy (in terms of reflux ratio profile) are determined. In both scenarios, maximisation of a profit function reflecting capital cost, operating cost and penalty due to under/over production and customer dissatisfaction is considered. A detailed dynamic model consisting of mass and energy balances with rigorous thermodynamic property calculation model is used. The optimisation problem is solved using modified simulated annealing algorithm.

Two ternary mixtures leading to easy and difficult separation were considered. The off‐cut production and recycling has been found to be more beneficial for difficult separation mixture than that for easy separation mixture. The net profit increases with over production more than under production of the products. This is because of the penalty imposed for customer dissatisfaction. It is better to over produce, as that will achieve the maximum profit and (at the same time) satisfy the customer. Finally, for a typical case study, the net profit with optimum design is found to be about 25 per cent more compared to the net profit obtained with fixed design.

Optimal design and operation of multicomponent batch distillation has received limited attention in the past. Also, these studies were not geared for fixed product demand scenario. The optimisation problem formulation considered in the past, led to unlimited production of products (based on the assumption that all products produced are saleable) to maximise the profitability. Also, there were no penalties for over or under production of the desired products, production of off‐cuts and customer dissatisfaction due to not meeting the order (amount of products and delivery time, etc.). In this work, for the first time, these issues are addressed in the optimisation problem formulation.

Places research undertaken into a periodic order cycle inventory management system for repetitive batch manufacturers into the context of lean production and world class manufacturing. Describes the attributes of the current marketplace, and how approaches used by successful users of the world‐class manufacturing and lean production techniques can be applied to a repetitive batch environment. Proposes a methodology to help traditional repetitive batch manufacturers in a route to continual improvement by: highlighting those areas where change would bring the greatest benefits; modelling the effect of proposed changes; quantifying the benefits that could be gained through implementing the proposed changes; and simplifying the effort required to perform the modelling process. Concentrates on increasing flexibility through managed inventory reduction by rationally decreasing batch sizes, taking account of sequence dependent set‐ups and the identification and elimination of bottlenecks.

The purpose of this paper is to develop new model formulation for reducing the workload in pre‐batching at a manufacturer of flavors and fragrances, by optimally assigning ingredients to different storage types, taking into account past usage of ingredients and several restrictions about volumes and number of storage units.

Two models were developed, using mathematical programming, accommodating either fixed or variable shelf settings in vertical carousel storage, along with other varying storage types. The models were validated, yielding a sizeable reduction in workload, and run under varying scenarios of storage additions to reduce workload even further.

For different storage addition scenarios, application of the new model formulation yielded a reduction of 22 percent in workload. In addition, aside from space savings, approximately 40 percent of refill order total waiting time was reduced due to improved allocation.

The authors' analysis was limited by considering direct cost savings only. Yet, reduced workloads in pre‐batching may also yield indirect cost savings, such as reduced quality costs, inventory costs, and investment savings by not having to extend the pre‐batching area. Such considerations may be addressed in future research, provided data on indirect savings are available.

While intuitive storage allocation overloads the pre‐batching department and increases space utilization, suggesting an incorrect perception that more personnel and space are needed, the proposed approach provides a better alternative through optimized allocations.

The present paper adds to the literature on carousel storage location by explicitly addressing the storage sizing issue, as well as workload balancing.

THE first part of this article, published in last month's issue of AIRCRAFT ENGINEERING, outlined the operation of the non‐statistical method of sampling inspection commonly met with in purchasing specifications, and explained the inability of such a sampling clause to discriminate effectively between good and bad quality product. The present issue describes the practical applications of statistically designed sampling inspection procedures, giving adequate quality assurance wherever 100 per cent inspection of the product is either inapplicable or uneconomic.

Presents a mathematical model for determining Economic Production Quantity (EPQ) in a multistage flow‐shop production system for the case where the demand for items per unit time is deterministic and the planning horizon is finite. Solves an example problem to illustrate the model.

Describes a study to measure the quality of service provided by food‐poisoning surveillance agencies in England and Wales in terms of the requirements of a representative consumer ‐ the egg producing industry ‐ adopting “egg associated” outbreak investigation reports as the reference output. Defines and makes use of four primary performance indicators: accessibility of information; completeness of evidence supplied in food‐poisoning outbreak investigation reports as to the sources of infection in “egg‐associated” outbreaks; timeliness of information published; and utility of information and advice aimed at preventing or controlling food poisoning. Finds that quality expectations in each parameter measured are not met. Examines reasons why surveillance agencies have not delivered the quality demanded. Makes use of detailed case studies to illustrate inadequacies of current practice. Attributes failure to deliver “accessibility” to a lack of recognition on the status or nature of “consumers”, combined with a self‐maintenance motivation of the part of the surveillance agencies. Finds that failures to deliver “completeness” and “utility” may result from the same defects which give rise to the lack of “accessibility” in that, failing to recognize the consumers of a public service for what they are, the agencies feel no need to provide them with the data they require. The research indicates that self‐maintenance by scientific epidemiologists may introduce biases which when combined with a politically inspired need to transfer responsibility for food‐poisoning outbreaks, skew the conduct of investigations and their conclusions. Contends that this is compounded by serious and multiple inadequacies in the conduct of investigations, arising at least in part from the lack of training and relative inexperience of investigators, the whole conditioned by interdisciplinary rivalry between the professional groups staffing the different agencies. Finds that in addition failures to exploit or develop epidemiological technologies has affected the ability of investigators to resolve the uncertainties identified. Makes recommendations directed at improving the performance of the surveillance agencies which, if adopted will substantially enhance food poisoning control efforts.