Life cycle modeling for adaptive and variant design part 2: case study

Life cycle modeling for design (LCMD) facilitates the incorporation of life cycle modeling into product design by including consideration of uncertainty in a products final specifications. The methodology combines Life Cycle Assessment with probabilistic design methods in a way that reduces information needs. Part 1 of this article presents the basic LCMD methodology. Here, in Part 2, LCMD is used to evaluate material substitution opportunities to reduce resource consumption, reduce life cycle air emissions, and increase the recyclable mass for a Ford C-class sedan. In addition to further illustrating LCMD, the case study identifies vehicle design scenarios that offer modest improvements in environmental performance and related cost tradeoffs.

Automatic conceptual design using experience-derived heuristics

Conceptual design is considered to be the most difficult phase of engineering design, with success dependent to a great extent on the expertise of the designer. Automation of some aspects of this phase would be of immense practical benefit. It is suggested that the generation of design solutions can be brought about through the application of heuristic knowledge. However, this sort of knowledge is in short supply and has proven difficult to acquire for computer systems. Nevertheless, actual examples of designers' work are more readily available, and the heuristics applied by designers may be considered to be implicit in these examples. The technique of Case-Informed Reasoning has been developed to try to exploit this potential source of knowledge, and applied to the task of fluid power circuit design, a configuration design task. This technique offers a practical approach to conceptual design automation in domains where design knowledge is lacking.

Postponing design processes in unpredictable environments

This work explores the effectiveness of design postponement in the concept development of large-scale engineering projects. Our empirical research shows limited use of postponement in semiconductor fabrication facility (fab) projects despite evidence that the customer inevitably requests design criteria changes in the projects life. We simulate fab concept development as a 2-stage process—conceptualization followed by design. We find that postponing the start of design in relation to the completion of conceptualization reduces the average resources spent on design and the variability in the concept development duration but increases the average concept development duration. A sensitivity analysis on the postponement lag duration indicates, however, that some degree of postponement may allow reducing design rework without increasing the risk of overrunning the project completion date, in comparison to the risk with early commitment. Further, simulation indicates that the effectiveness of postponement decreases as designers capability to reuse work increases.

Self-assembled nanowires on semiconductor surfaces

A number of different families of nanowires which self-assemble on semiconductor surfaces have been identified in recent years. They are particularly interesting from the standpoint of nanoelectronics, which seeks non-lithographic ways of creating interconnects at the nm scale (though possibly for carrying signal rather than current), as well as from the standpoint of traditional materials science and surface science. We survey these families and consider their physical and electronic structure, as well as their formation and reactivity. Particular attention is paid to rare earth nanowires and the Bi nanoline, both of which self-assemble on Si(001).Further information within the topic of this review article, including an up-to-date list of relevant publications, can be found on our Website. The address is:

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Customer Value Chain Analysis

Customer Value Chain Analysis (CVCA) is an original methodological tool that enables design teams in the product definition phase to comprehensively identify pertinent stakeholders, their relationships with each other, and their role in the product’s life cycle. By performing CVCA, design teams are better able to recognize diverse product requirements and their relative priority when undertaking Product Definition Assessment and using downstream ‘Design for X’ (DfX) tools. This paper discusses the evolution of the CVCA in response to the need for a DfX tool which is able to delineate customer needs early in the product development process. A step-by-step guide clarifies the implementation of CVCA with an example. Three case studies highlight the tool’s broad utility and important features to support design decision making, including: (1) confirmation of the product’s business model, (2) recognition of the critical stakeholders, and (3) clarification of the value proposition to be embedded in the product.

Morphology and constitution of the compound layer formed on nitrided Fe–4wt.%V alloy

The microstructure of the compound (“white”) layer formed on the surface of Fe–4wt.%V alloy, by nitriding in a gas mixture of ammonia and hydrogen at 580 °C, has been investigated by employing light and scanning electron microscopy, X-ray diffraction and electron probe microanalysis. The compound layer is dominantly composed of γ^|-Fe₄N nitride. Quantitative analysis of the composition data demonstrated that V is present in the compound layer as VN precipitates, i.e. V is not taken up significantly in (Fe, V) nitrides. A mechanism for compound-layer formation has been proposed.

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The synthesis and characterisation of grafted random styrene butadiene for biomedical applications

The work undertaken investigates the spectral, thermal and surface characteristics of a random styrene butadiene rubber (SBR) with monomeric graft(s) of acrylic acid (AA), N-vinyl-2-pyrrolidinone (NVP) or N-isopropylacrylamide (NIPAAm) synthesised using UV polymerisation. The grafted materials were characterised by differential scanning calorimetry (DSC), modulated differential scanning calorimetry (MDSC), attenuated total reflectance infrared Fourier transform spectrometry (ATR-FTIR) and atomic force microscopy (AFM). Thermograph analysis has shown an endothermic transition occurring at ~75 °C for all random SB-g-NVP copolymers, whereas the T _g value for random SB copolymer was found at 60 °C, thus suggesting that a chemical reaction between styrene and NVP had occurred. Similar thermal profiles to that of random SB-g-NVP copolymers were evident when random SB was UV polymerised with AA. When NIPAAm was grafted onto random SB, a notable exothermic transition was evident in all samples tested using DSC. It was established using MDSC that this exothermic transition was caused by the breakdown of crosslinks as a result of UV polymerisation.

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Project competence in product development

This paper presents and discusses the individual competence particularly required to work in project-organized product development. Individual competence encompasses the knowledge, skills and abilities to deal with issues related to organizational, social and technological factors involved in projects. The purpose has been to explore the competence required for project members at the operational level, and to explore the conditions for developing such competence. The study is based on a qualitative approach, with interviews as the tool for data collection. The study group comprised 54 respondents working in R&D departments within five large Swedish manufacturing companies. The findings reveal the need for project co-workers to be skilled in both practical and psychosocial aspects of co-ordination, time planning and control. The findings of the study demonstrate the importance of being able to cope with prescribed as well as unpredictable processes. They also indicate the effect of time on experience transfer.

Nitrogen absorption by Fe-1.04at.%Cr alloy: uptake of excess nitrogen

By dedicated pre-nitriding (at 580 °C in an ammonia/hydrogen gas atmosphere) and de-nitriding (at 470 °C in a hydrogen gas atmosphere) experiments, performed on Fe-1.04at.%Cr alloy, it could be demonstrated that the uptake of “excess” nitrogen by the nitrided ferritic matrix is not due to the presence of iron in chromium-nitride precipitates, as it was suggested previously. The determination of nitrogen-absorption isotherms for these pre-nitrided and de-nitrided Fe-1.04at.%Cr alloy specimens revealed that the total amount of excess nitrogen in the alloy is composed of two parts: (a) nitrogen adsorbed at the precipitate/matrix interface, and (b) nitrogen dissolved interstitially in the ferrite matrix strained by the misfit between (coherent) the CrN precipitates and the matrix.

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Optical switching of a photochromic bis-phenylazo compound in PMMA films

We present our results on a newly synthesized bis-phenylazo derivative, namely bisperfluoroalkylsulfonylamino- arylazomethylene-triphenyl-phosphorane (BAM-TPP). Thin films of BAM-TPP in polymethylmethacrylate (PMMA) matrix were prepared. The films (thickness, d < 60 μm) were exposed to UV-vis light with variable intensity in order to stimulate the photochromic reaction of BAM-TPP. The resulting absorption changes of the BAM-TPP/PMMA films were investigated by spectrophotometry. The absorption spectra reveal that BAM-TPP molecules in PMMA undergo photoisomerization with resulting decrease of absorbance in the range 500–700 nm. Finally, the time response of film transmittance at 514 nm under increasing CW light intensity was recorded, showing that the reverse photochromic process brings the absorbance back to its pristine value. The obtained films thus proved to be suitable for optical switching applications.

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Assessment of pre-combustion decarbonisation schemes for polygeneration from fossil fuels

This article deals with emerging poly-generation schemes that employ pre-combustion decarbonisation of fossil fuels—eventually with options for geological storage of the CO₂. Inevitably, such schemes are highly complex, and may require new approaches and knowledge on interactions between key components in large plants, as even new technologies and features are expected to occur in due course as the experience from polygeneration matures. Reference is made to the European DYNAMIS project and the Sino-European project COACH—both conducted under the auspices of the European Commission.

Are partwise comparisons reliable?

It is not unusual for decisions in engineering or customer surveys to compare pairs or subsets of alternatives. Surprisingly, this standard, natural approach can cause valued information to be lost: a loss so severe that it can cause demonstrably incorrect decisions. By understanding why these errors occur, we identify an alternative, closely related decision approach that eliminates these problems. Also, we identify the nature of the lost information, and we show how to compute the likelihood that an incorrect outcome will occur.

Identification and application of requirements and their impact on the design process: a protocol study

Establishing requirements is critical in designing, and therefore a central issue of design research. This article reports an empirical study, based on real-time protocol data about the design processes of four, experienced, individual designers, of how requirements get identified, clarified, and used in the design process, and how these influence the quality of its outcome - the emergent design. This is done by first identifying the activities and methods used by designers to identify and apply requirements during designing, and then investigating how these activities and methods relate to the success or failure of the eventual designs in terms of their degree of fulfilment of the requirements. The results indicate that the quality of the activities and methods used has a strong impact on the quality of the emergent design in terms of its degree of fulfilment of requirements, forming a basis for development of guidelines for effective requirement identification and application.

Composite bond inspection

After 50+ years of research to discover a way of determining the in situ strength of an adhesive bond, a method has been found to probe this key parameter. The initial testing on composite joints has shown it to be accurate and reliable. While effective, it is expensive to implement in a production environment and then during the final stages of assembly. A second method of probing the adherent surface prior to bonding is presented that offers the promise of determining adhesion potential before final bond consolidation. These new inspection methods should enable significant increases in structural performance for structures that utilize composite materials. Before examining these two new methods a brief review of past work on adhesive bond strength determination is presented.

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Product design in less industrialized economies: constraints and opportunities in Kenya

The ability for an economy to design useful products is tied to its productivity, thus economic growth and the population’s standards of living. This paper investigates product design strategies and processes in Kenya in the country’s informal, formal, and non-governmental sectors. In analyzing Kenyan 200+ products, patterns emerged to delineate four approaches to the detailed design acquisition of common-use products: imitated design, imported design, basic original design, and specialty design. A vast majority of product designs, 54 of 55 tracked in this research, originate outside the country or were imitated from imported products. Across sectors, there is emphasis on the detailed design and manufacturing phases of the design process. Factors specific to less industrialized economies (LIEs) like Kenya, such as corruption and an inadequate infrastructure, limit design activities relative to more industrialized economies. Design constraints observed in Kenya are believed to be similar to other economies at the same levels of industrialization. For product design to sustainably support economic development in LIEs, it is imperative that design process be consistent with local conditions and be user-centric in approach.

Special grain boundaries based on local symmetries

We propose that, in large unit cell structures, the operation of local symmetries rather than a coincidence site lattice (CSL), is important for the creation of special, low energy, grain and twin boundaries. We illustrate this with a Dürer tiling, and its monoclinic realization, as well as with crystals with large icosahedral motifs.

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