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The last decade witnessed the increasing use of Surface Mount Technology (SMT) in the assembly of Printed Circuit Boards (PCBs). This fact coupled with increasing component densities, decreasing component pitch, and the need for reliable PCBs has focused attention on the critical components of the manufacturing process including the adhesive used. Components used in PCBs manufactured using SMT, which are to be wave soldered, must be adhesively attached to the board so that they remain in place during the wave soldering process. Utilisation of non‐conducting adhesives for the attachment of electronic components prior to wave soldering has become common throughout the electronics manufacturing industry. The knowledge based adhesive selection adviser described in this paper assists the user (process engineer) in the selection of adhesives for wave soldering of surface mount components. In addition to guiding the user through the adhesive selection process, it provides dispenser related information. This ‘advice’ is derived from the restrictions imposed by the user (including the user's facility temperature), material property requirements, productivity measures and the adhesive dispensing method. The adhesive selection adviser helps the user understand the relationships that need to be considered during adhesive selection. It is applicable to any existing SMT line that uses adhesives within the commercial PCB manufacturing domain.

Surface mount technology (SMT) is being increasingly used in printed circuit board (PCB) assembly. The reduced lead pitch of surface mount components coupled with their increased lead count and packing densities have made it imperative that automated placement methods be used. However, the SMT placement process is often a bottleneck in surface mount manufacturing. A reduction in placement time in SMT will enhance throughput and productivity. This paper describes the design and development of a prototype expert system based approach which identifies ‘near’ optimal placement sequences for surface mount PCBs in (almost) realtime. The software structure used integrates a knowledge based system with an optimisation module. PROLOG is the language used in this research. The system was rigorously validated and tested. Ideas for further research are also presented.

During the insertion of pin‐in‐hole (PIH) components in a printed circuit board (PCB), adhesively bonded and/or soldered surface mount components (SMCs) already on the board experience mechanical stress. This paper describes the results of a study investigating the forces induced in the adhesive bond and the surface mounts during the insertion of dual inline package (DIP) components. The failure criteria for the glue bonds as well as the gullwing leads were determined from experimental strength tests. The forces in the glue and in the leads were calculated by a combination of analytical and finite element methods. It was found that the adhesive bond as well as the soldered gullwing lead would not fail under the forces induced in the insertion operation.

During the first half of this year the Association has continued to expand its exhibition programme by increasing its presence at overseas shows. Two DTI sponsored joint venture groups have been formed, one to Nepcon West, the other to Nepcon Beijing. Anaheim saw the biggest UK group for over 10 years, with CEMA taking three separate blocks in different sectors of the show. There is no doubt from the reception we received that CEMA is now firmly established at Nepcon West. We enjoyed tremendous support from both the British Consulate and the British‐American Chamber of Commerce with their President making several visits to the CEMA booth.

The purpose of this paper is to develop a novel automatic and accurate measurement technique for the volume of solder which is present in solder paste in pin‐in‐paste (PIP) technology and a calculation algorithm for predicting solder joint quality.

A new method is described for accurately determining the volume of solder alloy in solder paste that is present in and around the through hole, using X‐ray measurements (orthogonal view X‐ray images, instead of angle view), image processing and other calculations. In addition, various calibration tool constructions are investigated and a method is suggested for determining the calibration curve (for each solder paste) of an X‐ray machine.

A new calibration tool has been developed to accurately measure the calibration curve of X‐ray machines. Based on several tests, a fast and reliable image processing method for measuring the average grey scale of each pasted through hole is described. Numerous PIP solder joints have been created then analysed using the methodology. To verify the efficiency of the described methods, joints are soldered and inspected using cross‐sectioning and X‐ray imaging.

Calibration curve measurement of an X‐ray machine is done with the help of the developed tool for PIP technology. Orthogonal view X‐ray images are used to measure the volume of printed solder alloy (paste). During the image processing, circle fitting has been simplified to line fitting.

The purpose of the current study is to investigate occupational stereotypes among a professional sample of recruiters and other employees on the two fundamental dimensions of warmth and competence.

The authors conducted a survey to collect professionals´ (mostly recruiters´) ratings of preselected occupations. Participants were asked to rate warmth and competence attributes. Factor and cluster analysis were employed to investigate the two-dimensional structure of the warmth/competence space and how and whether occupations cluster as predicted by the stereotype content model (SCM).

Almost all occupations showed a clear two-factorial structure, corresponding to the warmth/competence dimensions. A five-cluster solution was deemed appropriate as depicting how occupations disperse on these dimensions. Implications for stereotyping research, the design of hiring discrimination experiments, and HRM are discussed.

In contrast to previous related research, in which participants select the included occupations themselves, the authors included prespecified common occupations, which should be important for representativeness. In addition, previous research has been conducted in the United States, while the authors conduct this study in a European context (Sweden). Finally, instead of studying students or participants with unspecified work experience, the authors focus on professionals (mostly recruiters).

This paper aims to present a robust prediction method for estimating the quality of electronic products assembled with pin-in-paste soldering technology. A specific board quality factor was also defined which describes the expected yield of the board assembly.

Experiments were performed to obtain the required input data for developing a prediction method based on decision tree learning techniques. A Type 4 lead-free solder paste (particle size 20–38 µm) was deposited by stencil printing with different printing speeds (from 20 mm/s to 70 mm/s) into the through-holes (0.8 mm, 1 mm, 1.1 mm, 1.4 mm) of an FR4 board. Hole-filling was investigated with X-ray analyses. Three test cases were evaluated.

The optimal parameters of the algorithm were determined as: subsample is 0.5, learning rate is 0.001, maximum tree depth is 6 and boosting iteration is 10,000. The mean absolute error, root mean square error and mean absolute percentage error resulted in 0.024, 0.03 and 3.5, respectively, on average for the prediction of the hole-filling value, based on the printing speed and hole-diameter after optimisation. Our method is able to predict the hole-filling in pin-in-paste technology for different through-hole diameters.

No research works are available in current literature regarding machine learning techniques for pin-in-paste technology. Therefore, we decided to develop a method using decision tree learning techniques for supporting the design of the stencil printing process for through-hole components and pin-in-paste technology. The first pass yield of the assembly can be enhanced, and the reflow soldering failures of pin-in-paste technology can be significantly reduced.

Reviews stencil design requirements for printing solder paste around and in through‐hole pads/openings. There is much interest in this procedure since full implementation allows the placement of both through‐hole components as well as surface mount devices and the subsequent reflow of both simultaneously. This in turn eliminates the need to wave solder or hand solder through‐hole components. The effect of component material type, pin type, lead length, and standoff height of the through hole components is reviewed. Board design issues including plated through‐hole size, pad size, board thickness, and solder mask type are also reviewed. Three stencil designs are considered: single thickness stencils with oversized stencil apertures for overprinting solder paste in the through‐hole pad areas; step stencils with oversized stencil apertures for overprinting solder paste in the through‐hole pad areas; thick stencils (0.384‐0.635 mm thick) for printing solder paste in the through‐hole pad areas. The latter thick stencil is the second stencil in the two‐print stencil process. Several examples are reviewed with the recommended stencil designs.

The purpose of this paper is to explain why the high quality cassava flour (HQCF) value chain in Nigeria has not performed as well as expected. The specific objectives are to: analyse important sources of uncertainty influencing HQCF value chains; explore stakeholders’ strategies to respond to uncertainty; and highlight the implications of different adaptation strategies for equity and the environment in the development of the value chain.

The authors used a conceptual framework based on complex adaptive systems to analyse the slow development of the value chain for HQCF in Nigeria, with a specific focus on how key stakeholders have adapted to uncertainty. The paper is based on information from secondary sources and grey literature. In particular, the authors have drawn heavily on project documents of the Cassava: Adding Value for Africa project (2008 to present), which is funded by the Bill & Melinda Gates Foundation, and on the authors’ experience with this project.

Policy changes; demand and supply of HQCF; availability and price of cassava roots; supply and cost of energy are major sources of uncertainty in the chain. Researchers and government have shaped the chain through technology development and policy initiatives. Farmers adapted by selling cassava to rival chains, while processors adapted by switching to rival cassava products, reducing energy costs and vertical integration. However, with uncertainties in HQCF supply, the milling industry has reserved the right to play. Vertical integration offers millers a potential solution to uncertainty in HQCF supply, but raises questions about social and environmental outcomes in the chain.

The use of the framework of complex adaptive systems helped to explain the development of the HQCF value chain in Nigeria. The authors identified sources of uncertainty that have been pivotal in restricting value chain development, including changes in policy environment, the demand for and supply of HQCF, the availability and price of cassava roots, and the availability and cost of energy for flour processing. Value chain actors have responded to these uncertainties in different ways. Analysing these responses in terms of adaptation provides useful insights into why the value chain for HQCF in Nigeria has been so slow to develop.

Recent developments suggest that the most effective strategy for the milling industry to reduce uncertainty in the HQCF value chain is through vertical integration, producing their own cassava roots and flour. This raises concerns about equity. Until now, it has been assumed that the development of the value chain for HQCF can combine both growth and equity objectives. The validity of this assumption now seems to be open to question. The extent to which these developments of HQCF value chains can combine economic growth, equity and environmental objectives, as set out in the sustainable development goals, is an open question.

The originality lies in the analysis of the development of HQCF value chains in Nigeria through the lens of complex adaptive systems, with a particular focus on uncertainty and adaptation. In order to explore adaptation, the authors employ Courtney et al.’s (1997) conceptualization of business strategy under conditions of uncertainty. They argue that organisations can assume three strategic postures in response to uncertainty and three types of actions to implement that strategy. This combination of frameworks provides a fresh means of understanding the importance of uncertainty and different actors’ strategies in the development of value chains in a developing country context.

Problems with learning disabilities are life affecting (Murray, C., Goldstein, D. E., & Nourse, S. (2000). The postsecondary school attendance and completion rates of high school graduates with learning disabilities. Learning Disabilities Research and Practice, 15, 182–186; Westby, 2000; Rojewski, 1999a; Hall et al., 2002). The impact of poor mathematical skills on employment prospects is even bigger than the influence of poor reading skills (Dowker, 2005). After an introduction on the definition, prevalence and impact, gender and birth order, subtypes, comorbidity and assessment of cognition and metacognition in mathematical learning disabilities, we will focus on the features of mathematical learning disabilities in adolescence and adulthood and on the STI(mulation), CO(mpensation), R(emediation) and DI(spensation) (STICORDI) devices to help students with mathematical learning disabilities. With such devices “reasonable” adjustments are provided to ensure that disabled students are not placed at a substantial disadvantage compared to non-disabled students.