Flow and pressure drop on the shellside of cylindrical heat exchangers

This work presents pressure distributions and fluid flow patterns on the shellside of a cylindrical shell-and-tube heat exchanger. The apparatus used was constructed from glass enabling direct observation of the flow using a dye release technique and had ten traversable pressure instrumented tubes permitting detailed pressure distributions to be obtained. The `exchanger' had a large tube bundle (278 tubes) and main flow areas typical of practical designs. Six geometries were studied: three baffle spacings both with and without baffle leakage. Results are also presented of three-dimensional modelling of shellside flows using the Harwell Laboratory's FLOW3D code. Flow visualisation provided flow patterns in the central plane of the bundle and adjacent to the shell wall. Comparison of these high-lighted significant radial flow variations. In particular, separated regions, originating from the baffle tips, were observed. The size of these regions was small in the bundle central plane but large adjacent to the shell wall and extended into the bypass lane. This appeared to reduce the bypass flow area and hence the bypass flow fraction. The three-dimensional flow modelling results were presented as velocity vector and isobar maps. The vector maps illustrated regions of high and low velocity which could be prone to tube vibration and fouling. Separated regions were also in evidence. A non-uniform crossflow was discovered with, in general, higher velocities in the central plane of the bundle than near the shell wall._The form of the isobar maps calculated by FLOW3D was in good agreement with experimental results. In particular, larger pressure drops occurred across the inlet than outlet of a crossflow region and were higher near the upstream than downstream baffle face. The effect of baffle spacing and baffle leakage on crossflow and window pressure drop measurements was identified. Agreement between the current measurements, previously obtained data and commonly used design correlations/models was, in general, poor. This was explained in terms of the increased understanding of shellside flow. The bulk of previous data, which dervies from small-scale rigs with few tubes, have been shown to be unrepresentative of typical commerical units. The Heat Transfer and Fluid Flow Service design program TASC provided the best predictions of the current pressure drop results. However, a number of simple one-dimensional models in TASC are, individually, questionable. Some revised models have been proposed.

INTAMAP: the design and implementation of an interoperable automated interpolation web service

INTAMAP is a Web Processing Service for the automatic spatial interpolation of measured point data. Requirements were (i) using open standards for spatial data such as developed in the context of the Open Geospatial Consortium (OGC), (ii) using a suitable environment for statistical modelling and computation, and (iii) producing an integrated, open source solution. The system couples an open-source Web Processing Service (developed by 52°North), accepting data in the form of standardised XML documents (conforming to the OGC Observations and Measurements standard) with a computing back-end realised in the R statistical environment. The probability distribution of interpolation errors is encoded with UncertML, a markup language designed to encode uncertain data. Automatic interpolation needs to be useful for a wide range of applications and the algorithms have been designed to cope with anisotropy, extreme values, and data with known error distributions. Besides a fully automatic mode, the system can be used with different levels of user control over the interpolation process.

How effective is low vision service provision? A systematic review

Visual impairment is a large and growing socioeconomic problem. Good evidence on rehabilitation outcomes is required to guide service development and improve the lives of people with sight loss. Of the 478 potentially relevant articles identified, only 58 studies met our liberal inclusion criteria, and of these only 7 were randomized controlled trials. Although the literature is sufficient to confirm that rehabilitation services result in improved clinical and functional ability outcomes, the effects on mood, vision-related quality of life (QoL) and health-related QoL are less clear. There are some good data on the performance of particular types of intervention, but almost no useful data about outcomes in children, those of working age, and other groups. There were no reports on cost effectiveness. Overall, the number of well-designed and adequately reported studies is pitifully small; visual rehabilitation research needs higher quality research. We highlight study design and reporting considerations and suggest a future research agenda.

Premium e-grocery:exploring value in logistics integrated service solutions

E-grocery is gradually becoming viable or a necessity for many families. Yet, most e-supermarkets are seen as providers of low value "staple" and bulky goods mainly. While each store has a large number of SKU available, these products are mainly necessity goods with low marginal value for hedonistic consumption. A need to acquire diverse products (e.g., organic), premium priced products (e.g., wine) for special occasions (e.g., anniversary, birthday), or products just for health related reasons (e.g., allergies, diabetes) are yet to be served via one-stop e-tailers. In this paper, we design a mathematical model that takes into account consumers' geo-demographics and multi-product sourcing capacity for creating critical mass and profit. Our mathematical model is a variant of Capacitated Vehicle Routing Problem with Time Windows (CVRPTW), which we extend by adding intermediate locations for trucks to meet and exchange goods. We illustrate our model for the city of Istanbul using GIS maps, and discuss its various extensions as well as managerial implications.

The UK productivity gap in the service sector: do management practices matter?

Purpose – This paper aims to contribute to the debate on the drivers of the productivity gap that exists between the UK and its major international competitors. Design/methodology/approach – From the macro perspective the paper explores the quantitative evidence on the productivity differentials and how they are measured. From the micro perspective, the article explores the quantitative evidence on the role of management practices claimed to be a key determinant in promoting firm competitiveness and in bridging the UK gap. Findings – This study suggests that management practices are an ambiguous driver of firm productivity and higher firm performance. On the methodological side, qualitative and subjective measures of either management practices or firm performance are often used. This makes the results not comparable across studies, across firms or even within firms over time. Productivity and profitability are often and erroneously interchangeably used while productivity is only one element of firm performance. On the other hand, management practices are multi-dimensional constructs that generally do not demonstrate a straightforward relationship with productivity variables. To assume that they are the only driver of higher productivity may be misleading. Moreover, there is evidence of an inverse causal relationship between management practices and firm performance. This calls into question most empirical results of the extant literature based on the unidirectional assumption of direct causality between management practices and firm performance. Research limitations/implications – These and other issues suggest that more research is needed to deepen the understanding of the UK productivity gap and more quantitative evidence should be provided on the way in which management practices contribute to the UK competitiveness. Their impact is not easily measurable due to their complexity and their complementary nature and this is a fertile ground for further research. Originality/value – This paper brings together the evidence on the UK productivity gap and its main drivers, provided by the economics, management and performance measurement literature. This issue scores very highly in the agenda of policy makers and academics and has important implications for practitioners interested in evaluating the impact of managerial best practices.

Does role clarity explain employee-perceived service quality? A study of antecedents and consequences in call centres

Purpose – Role clarity of frontline staff is critical to their perceptions of service quality in call centres. The purpose of this study is to examine the effects of role clarity and its antecedents and consequences on employee-perceived service quality. Design/methodology/approach – A conceptual model, based on the job characteristics model and cognitive theories, is proposed. Key antecedents of role clarity considered here are feedback, autonomy, participation, supervisory consideration, and team support; while key consequences are organizational commitment, job satisfaction and service quality. An internal marketing approach is adopted and all variables are measured from the frontline employee's perspective. A structural equation model is developed and tested on a sample of 342 call centre representatives of a major commercial bank in the UK. Findings – The research reveals that role clarity plays a critical role in explaining employee perceptions of service quality. Further, the research findings indicate that feedback, participation and team support significantly influence role clarity, which in turn influences job satisfaction and organizational commitment. Research limitations/implications – The research suggests that boundary personnel in service firms should strive for more clarity in perceived role for delivering better service quality. The limitations are in sample availability from in-house transaction call centres of a single bank. Originality/value – The contributions of this study are untangling the confusing research evidence on the effect of role clarity on service quality, using service quality as a performance variable as opposed to productivity estimates, adopting an internal marketing approach to understanding the phenomenon, and introducing teamwork along with job-design and supervisory factors as antecedent to role clarity.

Managing people and performance:An evidence based framework applied to health service organizations

People and their performance are key to an organization's effectiveness. This review describes an evidence-based framework of the links between some key organizational influences and staff performance, health and well-being. This preliminary framework integrates management and psychological approaches, with the aim of assisting future explanation, prediction and organizational change. Health care is taken as the focus of this review, as there are concerns internationally about health care effectiveness. The framework considers empirical evidence for links between the following organizational levels: 1. Context (organizational culture and inter-group relations; resources, including staffing; physical environment) 2. People management (HRM practices and strategies; job design, workload and teamwork; employee involvement and control over work; leadership and support) 3. Psychological consequences for employees (health and stress; satisfaction and commitment; knowledge, skills and motivation) 4. Employee behaviour (absenteeism and turnover; task and contextual performance; errors and near misses) 5. Organizational performance; patient care. This review contributes to an evidence base for policies and practices of people management and performance management. Its usefulness will depend on future empirical research, using appropriate research designs, sufficient study power and measures that are reliable and valid.

Exploring value through integrated service solutions:the case of e-grocery shopping

Purpose – The purpose of this paper is to demonstrate the need for an improved understanding of consumer value for online grocery purchases and to propose the notion of “integrated service solution” packages as a strategy for growing and successfully sustaining the channel to guide both marketing strategy and policy. Design/methodology/approach – This paper integrates and synthesises research from retailing, consumer behaviour and service quality literatures in order to develop a conceptual framework for understanding the value of e-grocery shopping to aid practitioners to address the critical needs, expectations and concerns of consumers for the development of grocery shopping within the online environment. Findings – This paper offers an alternative approach to allow e-grocery to become a mainstream retail channel in its own right and not to compete with the in-store offerings. The research demonstrates the need for a progressive approach that follows contemporary consumer needs and habits at the household level. The conjecture is that shopping for fast-moving consumer goods follows a learning path that needs to be replicated in the online context. Moreover, it is suggested that consumer resistance to the adoption of the new channel should be addressed not only from a technological perspective but also from the social aspects of online shopping. Originality/value – The research provides a practical framework for both retailers and policy makers on how the “next generation” of online services can be developed using a “bottom up” consumer perspective. This paper also advocates a non-technological bias to e-grocery retailing strategy.

Aspects of the design and operation of production control systems in manufacturing industry

Computerised production control developments have concentrated on Manufacturing Resources Planning (MRP II) systems. The literature suggests however, that despite the massive investment in hardware, software and management education, successful implementation of such systems in manufacturing industries has proved difficult. This thesis reviews the development of production planning and control systems, in particular, investigates the causes of failures in implementing MRP/MRP II systems in industrial environments and argues that the centralised and top-down planning structure, as well as the routine operational methodology of such systems, is inherently prone to failure. The thesis reviews the control benefits of cellular manufacturing systems but concludes that in more dynamic manufacturing environments, techniques such as Kanban are inappropriate. The basic shortcomings of MRP II systems are highlighted and a new enhanced operational methodology based on distributed planning and control principles is introduced. Distributed Manufacturing Resources Planning (DMRP), was developed as a capacity sensitive production planning and control solution for cellular manufacturing environments. The system utilises cell based, independently operated MRP II systems, integrated into a plant-wide control system through a Local Area Network. The potential benefits of adopting the system in industrial environments is discussed and the results of computer simulation experiments to compare the performance of the DMRP system against the conventional MRP II systems presented. DMRP methodology is shown to offer significant potential advantages which include ease of implementation, cost effectiveness, capacity sensitivity, shorter manufacturing lead times, lower working in progress levels and improved customer service.

Multiple paradigms and organisational research: an analysis of work behaviour in the fire service

The thesis examines Kuhn's (1962, 1970) concept of paradigm, assesses how it is employed for mapping intellectual terrain in the social sciences, and evaluates it's use in research based on multiple theory positions. In so doing it rejects both the theses of total paradigm 'incommensurability' (Kuhn, 1962), and also of liberal 'translation' (Popper, 1970), in favour of a middle ground through the 'language-game of everyday life' (Wittgenstein, 1953). The thesis ultimately argues for the possibility of being 'trained-into' new paradigms, given the premise that 'unorganised experience cannot order perception' (Phillips, 1977). In conducting multiple paradigm research the analysis uses the Burrell and Morgan (1979) model for examining the work organisation of a large provincial fire Service. This analysis accounts for firstly, a 'functionalist' assessment of work design, demonstrating inter alia the decrease in reported motivation with length of service; secondly, an 'interpretive' portrayal of the daily accomplishment of task routines, highlighting the discretionary and negotiated nature of the day's events; thirdly, a 'radical humanist' analysis of workplace ideology, demonstrating the hegemonic role of officer training practices; and finally, a 'radical structuralist' description of the labour process, focusing on the establishment of a 'normal working day'. Although the argument is made for the possibility of conducting multiple paradigm research, the conclusion stresses the many institutional pressures serving to offset development.

Design of a stock control methodology for use within an oil blending company

The thesis deals with the background, development and description of a mathematical stock control methodology for use within an oil and chemical blending company, where demand and replenishment lead-times are generally non-stationary. The stock control model proper relies on, as input, adaptive forecasts of demand determined for an economical forecast/replenishment period precalculated on an individual stock-item basis. The control procedure is principally that of the continuous review, reorder level type, where the reorder level and reorder quantity 'float', that is, each changes in accordance with changes in demand. Two versions of the Methodology are presented; a cost minimisation version and a service level version. Realising the importance of demand forecasts, four recognised variations of the Trigg and Leach adaptive forecasting routine are examined. A fifth variation, developed, is proposed as part of the stock control methodology. The results of testing the cost minimisation version of the Methodology with historical data, by means of a computerised simulation, are presented together with a description of the simulation used. The performance of the Methodology is in addition compared favourably to a rule-of-thumb approach considered by the Company as an interim solution for reducing stack levels. The contribution of the work to the field of scientific stock control is felt to be significant for the following reasons:- (I) The Methodology is designed specifically for use with non-stationary demand and for this reason alone appears to be unique. (2) The Methodology is unique in its approach and the cost-minimisation version is shown to work successfully with the demand data presented. (3) The Methodology and the thesis as a whole fill an important gap between complex mathematical stock control theory and practical application. A brief description of a computerised order processing/stock monitoring system, designed and implemented as a pre-requisite for the Methodology's practical operation, is presented as an appendix.

Proliferative diabetic retinopathy (R3) referrals from the digital diabetic retinopathy screening program:urgency of appointment in the hospital eye service achieved and needed?

DESIGN. Retrospective analysis PURPOSE. To assess the clinical characteristics and outcomes of patients identified with proliferative diabetic retinopathy (PDR) referred from the screening program to the hospital eye services (HES) METHODS. a retrospective analysis of urgently referred PDR cases to Birmingham Heartlands HES from august 2008 until July 2010 RESULTS. 130 urgent diabetic retinopathy referrals were made and reviewed. 103 (68% male, 80% type 2 diabetes) were referred for PDR with a mean age of 59 years, mean diabetes duration of 17.8years. 69% were on insulin treatment at the time of the screening, with mean HbA1c of 10.4% (range-5.7 to 16.5%). 65% of the patients were offered appointments at HES within two weeks after referral from the screening. 50.5% of the patients were seen in the HES within 2 weeks, 22 and 16 % were seen 2-4 and 4-8 weeks after referral respectively. 6 patients never attended ophthalmology examination during the two years of review. Of all the attendees, 56% were booked for pan retinal photocoagulation (PRP) & 9(9.3%) for macular laser respectively on their 1st HES visit. 75% of the patients were newly diagnosed PDR and 26 had previous PRP laser but lost to follow up. 63 patients ( 66%) received either PRP or macular laser treatment (85.7% of which is PRP). 63% of the PRP treatment was performed within a month of first HES attendance. Retinopathy grading discrepancy between the screening program and HES was noted in 20% (21 patients). CONCLUSIONS. This data suggests that the digital screening programme is appropriately identifying high risk patients with PDR with timely PRP laser treatment in the majority of patients but raises concern over patients lost to follow up (hence failsafe tracking of appointment attendance), and review of grading discrepancies between the ophthalmology and screening service.

Knowledge management in knowledge intensive service networks:a strategic management approach

Purpose – The main purpose of this paper is to analyze knowledge management in service networks. It analyzes the knowledge management process and identifies related challenges. The authors take a strategic management approach instead of a more technology-oriented approach, since it is believed that managerial problems still remain after technological problems are solved. Design/methodology/approach – The paper explores the literature on the topic of knowledge management as well as the resource (or knowledge) based view of the firm. It offers conceptual insights and provides possible solutions for knowledge management problems. Findings – The paper discusses several possible solutions for managing knowledge processes in knowledge-intensive service networks. Solutions for knowledge identification/generation, knowledge application, knowledge combination/transfer and supporting the evolution of tacit network knowledge include personal and technological aspects, as well as organizational and cultural elements. Practical implications – In a complex environment, knowledge management and network management become crucial for business success. It is the task of network management to establish routines, and to build and regularly refresh meta-knowledge about the competencies and abilities that exist within the network. It is suggested that each network partner should be rated according to the contribution to the network knowledge base. Based on this rating, a particular network partner is a member of a certain knowledge club, meaning that the partner has access to a particular level of network knowledge. Such an established routine provides strong incentives to add knowledge to the network's knowledge base Originality/value – This paper is a first attempt to outline the problems of knowledge management in knowledge-intensive service networks and, by so doing, to introduce strategic management reasoning to the discussion.

Effects of retail employees' behaviours on customers' service evaluation

Purpose – The purpose of this paper is to test a conceptual model of the effects of customer and service orientation (SO) behaviours of individual retail employees on individual customers’ perceptions of service encounter quality (SEQ), service quality (SQ), value, satisfaction, and behavioural intentions (BI). Design/methodology/approach – The sample (n ¼ 271) was customers of a supermarket in central India, and they completed questionnaires following mall intercept. To test the hypotheses, structural equation modelling using LISREL 8.7 was employed. Findings – It was found that: service and customer orientation (CO) behaviours are positively related to SEQ and SQ; SEQ is positively related to SQ and customer satisfaction; SQ is positively related to value perceptions and customer satisfaction; and customer satisfaction is positively related to retail customers’ BI. However, value is not related to customer satisfaction. Research limitations/implications – More research is needed on customer perceptions of value in non-Western contexts and service evaluation frameworks in other cross-cultural contexts. Practical implications – Retail managers need to train or select retail personnel who are able to perform their roles in a service-oriented and customer-oriented way, and value does not appear to be as important to Indian retail customers as it is to Western retail customers. Originality/value – This paper extends current service evaluation frameworks by including SO and CO as antecedents, and it analyses an Indian retail context. Keywords India, Retailing, Customer satisfaction, Service levels, Employee behaviour.