An appraisal of ecolabelling from a design perspective

This paper considers the design implications of the European ecolabelling scheme. The aims and procedures of this procedures of this product level market instrument are examined and appraised with regard to impact on product design. The paper concludes that ecolabelling, as presently defined, will have a limited affect on promoting widespreads design and provision of environmentally sensitive products. A ‘product selection model’ is therefore proposed that makes for more effective ecolabelling. This in turn is developed to provide an ‘ecodesign emphasis model’ to indicate design options that can shift products towards an optimum and sustainable ‘green’ target.     

Two functions of analogical reasoning in design: a cognitive-psychology approach

On the basis of data collected in three empirical studies conducted on industrial designers, this paper identifies two different types of ‘spontaneous’ use of analogy in design. Focus is on the first ‘stages’ of analogical reasoning, i.e. construction of a target representation, and search and retrieval of a source. At the action-execution level, analogies are used in order to solve the current design problem; at the action-management level, in order to make the action-execution process cognitively more economical. Differences between the uses concern their dependence on the routine character of the task, the distance between target and source, and their link with creativity and reuse (or case-based reasoning).     

Experimental study and numerical simulation of pipe-on-pipe impact

Experiments and numerical simulations were conducted to investigate the dynamic response in a pipe-on-pipe impact event, in which a missile (swinging) pipe with one end hinged and the other end free impinges on an orthogonal simply-supported/clamped target pipe at its centre. This study focuses on the effects of the impact location on the missile pipe and the wall thickness of the pipes. The experiments were carried out by using a spring-powered catapult impact setup, the specimens used were made of seamless steel pipes of two different thicknesses, 1 mm and 3 mm respectively, and the target pipes were clamped. Seven tests were carried out using the catapult. Numerical simulations using the explicit finite element code LS-DYNA were performed on an HPC360 workstation for each of the seven test cases. The results of the experiments and numerical simulations were compared, showing good agreement. Having confirmed the validity of the numerical model, numerical simulations were applied to the cases of a simply-supported target pipe, and the partitioning of the energy dissipation was calculated. As the response mode depends significantly on the initial impact position, the evolution of the response mode was examined numerically as the point of impact on the missile pipe was moved from the hinged end to the free end. It was found that there is a particular impact location for which the target pipe was most seriously damaged using the same impact speed.     

Yield and ultimate strengths of fibre composite laminates

A modified maximum strain failure criterion is proposed to predict the failure of the laminae of fibre-reinforced composites when the laminate is subjected to combined loading. The criterion includes two levels of failure. The lower level predicts the onset of stiffness degradation or ‘yield’ in the lamina. Beyond this level the lamina response is non-linear until the upper lever is reached, which corresponds to ‘ultimate’ failure. After the ultimate failure of a ply in a laminate in a certain mode it is assumed that the failed layer unloads gradually in the same mode only. The theoretical predictions of the present analysis are compared with predictions of other failure theories as well as with experimental data obtained from tests on composite tubular specimens.     

Combinatorial solid state chemistry by multitarget laser ablation: a way for the elaboration of new superconducting cuprates thin films?

Laser ablation by varying the number of consecutive laser pulses upon two targets, one superconducting YBa₂Cu₃O₇, the other insulating MCuO₂ (M=Sr, Ca), is used to build thin films of tuneable average compositions. Most of the samples are found to display high-T_c superconductivity with critical temperature generally higher than the 60 K of the ‘Cava phase’, the prototypic structure with two consecutive conducting CuO₂ planes and containing same types of atoms. The properties of the samples are not linearly dependent on the concentration of species coming from the insulating target. In addition, they depend not only on the ratio of the number of pulses on each target, but also on the number of consecutive pulses on each target. Thin films are characterized by temperature-dependent DC conductivity, X-ray diffraction, Castaing microprobe and infrared reflectivity spectroscopy. Present results suggest the robustness of high-T_c superconductivity, possibly related to a ‘Cava-phase-like’ skeleton.     

Design method and scientific method

A recurring theme in recent design theory has been a desire to relate design method to scientific method: to create the ‘science of design’ or a ‘design science’. There is an inherent paradox in such a desire since design and science are clearly very dissimilar kinds of activities. Further, the concept of ‘scientific method’ now seems to be in epistemological chaos. For these reasons, attempts to model design method on scientific method seem misplaced. It is proposed that it would be more fruitful to regard design as a technology, rather than as a science. The paper seeks to establish the basis for such a view, drawing especially on the idea that both design and technology involve the application of types of knowledge other than the purely ‘scientific’ kind.     

Modelling of the mechanical behaviour of a 2-D SiC-SiC composite at a meso-scale

An original meso-model of the mechanical behaviour of a 2-D SiC-SiC composite is proposed. In order to take into account the main elementary constituents of the composite (which govern the material damage), the composite material and the damage mechanisms are described at an intermediate scale referred to as the meso-scale. The laminate meso-model is defined with an arrangement of one ‘inter-tow matrix and pores’ ply and four ‘unidirectional composite’ plies. The model is validated on the basis of comparisons between numerical simulations of the mechanical behaviour of the composite under both off-axis tensile (or biaxial stress state) testing conditions, and experimental data.     

Treatment of nondetects in multivariate analysis of groundwater geochemistry data

Principal components analysis (PCA) is used to evaluate similarities in the trace element chemistry of groundwaters. Many of the trace elements, however, occur at concentrations below the detection limits (DL), which presents problems for statistical analyses. Since the optimal methods for dealing with the ‘

In this study, a new approach was developed to determine the best substitution methods when dealing with the ‘DL’ values for a given data set. Monte Carlo simulation experiments, using a mixture multivariate model, were performed to test the effects of substitution of the ‘

When ‘相似文献   

Long-term effects of legislation and local promotion of child restraint use in motor vehicles in Sweden

The main objective is to study long-term effects of legislation and promotion of child-restraint use in motor vehicles. Subgoals are to describe the level of restraint use in cars and changes in mortality and morbidity patterns in regard to differences among age groups and geographical areas (morbidity). The study areas were; ‘The First Four’, ‘The Six Counties’, ‘The Rest of Sweden’, and ‘Sweden as a whole’, and the population were two age groups — 0–6 and 7–14 years. The incidence of restraint use comes from observations of car-seat-belt usage. Outcome evaluation was based on hospital-discharge data 1978–1996 and mortality statistics 1970–1996. The level of restraint use for children in the front seat was 97% in 1988 and was equal to 1995. Mortality data shows a decrease of 2.8% on an average per year, 76% over the study period. A significant change over time in the two intervention areas was shown (annual changes of −2.8 and −1.8%), but not in the rest of Sweden. The local authorities that started early with preventive programs, such as safety seat loan schemes and those having an organised safety-promotion program showed a much better improvement than the rest of Sweden. There is a need for appropriate information for local action on childhood injury prevention to accompany national legislation.     

Modelling the factors related to the seatbelt use by the young drivers of Athens

Road traffic accidents in Greece are one of the major problems of the public health sector and the first cause of death in the ages 18–24. However, there are no records available for defining the determinants of road accidents and seatbelt wearing rates. The main objective of this study is to determine and clarify the relationship between young drivers’ intentions (motivation to use/non use seatbelt) and their behaviour (self-reported use). Additionally, the purpose of this study is to evaluate the seatbelt wearing rates among young drivers in relation to their trip-type. The sample consisted of 200 young Greek drivers of both sexes. The statistical analysis included factor analysis and multiple regression analysis. The seatbelt use was measured in relation with seven trip-types. Through factor analysis, a seven factor scale of seatbelt use and a four factor scale of seatbelt non use were created which included Greek young drivers’ basic motivations for wearing or not wearing a seatbelt. A model, constructed by the multiple regression analysis, revealed the factors related with the seatbelt use. The factors positively related were ‘imitation’, ‘self-protection’, and ‘legality’. The factor of ‘discomfort’ is negatively associated with the seatbelt use. Furthermore, mileage was negatively related with seatbelt use. Finally, some preliminary suggestions on how prevention strategies should be implemented in Greece are discussed.     

Microscopic fatigue processes in a plain-weave glass-fibre composite

This paper focuses on the microscopic damage and progressive failure of a composite reinforced by plain-weave glass cloth under tensile fatigue loading. The fatigue process was divided into three stages like that of multi-directional laminates. It was found that the internal damage at each stage (matrix cracks, debonds in the weft, successive debonds in the warp and ‘metadelaminations’ between warps and wefts) occurred near the cross-over point of the fabric. The modulus decay mechanism was explained by considering the progression of this internal damage. From the end of the first stage to the beginning of the middle stage, a characteristic damage state (CDS) (called a ‘meta-CDS’) was observed. It was found that woven composites have a unit area of damage accumulation (called a ‘unit cell’) and the damage of each unit cell and its distribution control the total fatigue damage of the material.     

Hydromagnetic convection flow through a porous medium in axially varying pipe

The hydromagnetic mixed convection flow through a porous medium in a pipe of varying radius in a uniform axial magnetic field is analyzed. The pipe wall is maintained at a prescribed nonuniform temperature. The governing equations are solved analytically to obtain the velocity, temperature, and induced magnetic field. Their behaviors are evaluated for different variations in the governing parameters. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 79, No. 4, pp. 96–104, July–August, 2006.     

In situ RHEED control of self-organized Ge quantum dots

In situ registration of high-energy electron diffraction patterns was used for constructing the diagram of structural and morphological states of the Ge film on the Si(100) surface. The following regions identified in the diagram: two-dimensional (2D)-growth, ‘hut’- and ‘dome’-clusters, ‘dome’-clusters with misfit dislocations at the interface. Variations in the lattice constants of the Ge film during the MBE growth on the Si(100) surface were determined. An increase in the lattice constant at the (100) surface was attributed to the elastic deformation at the stage of 2D growth and formation of ‘hut’-clusters and to the plastic relaxation for the ‘dome’-clusters. As a result, epitaxial silicon structures with germanium quantum dots of 15 nm base size at the density of 3×10¹¹ cm⁻² were synthesized. The total electron structure of the hole spectrum of Ge quantum dots in Si was established.     

Cyclic response of a 1Cr-Mo-V low alloy steel

The high strain fatigue behaviour of a bainitic (‘Non-heat-treated’) and a tempered bainitic (‘Heat-treated’) alloy steel has been studied at room temperature and 565°C. Cyclic softening is observed in all cases and is associated with dislocation redistribution, alignment and channelling of precipitates, and their growth at 565°C. Comparison of the appropriate monotonic and cyclic stress/strain curves enables a tentative estimate of the relative significance of these mechanisms to be made.     

Regularization of hypersingular boundary integral equations: a new approach for axisymmetric elasticity

A hypersingular boundary integral equation (HBIE) formulation, for axisymmetric linear elasticity, has been recently presented by de Lacerda and Wrobel [Int. J. Numer. Meth. Engng 52 (2001) 1337]. The strongly singular and hypersingular equations in this formulation are regularized by de Lacerda and Wrobel by employing the singularity subtraction technique. The present paper revisits the same problem. The axisymmetric HBIE formulation for linear elasticity is interpreted here in a ‘finite part’ sense and is then regularized by employing a ‘complete exclusion zone’. The resulting regularized equations are shown to be simpler than those by de Lacerda and Wrobel.     

Stress intensity factors for circumferential semielliptical surface cracks in a pipe under thermal loading

Stress intensity factors are calculated at the deepest point and at the surface points of circumferential semielliptical surface cracks in a thermally shocked pipe. The method of calculation is based on weight functions following a proposal by Munz et al. Numerical values of the stress intensity factors are given for a wide range of crack depths and crack lengths considering a pipe with a wall thickness to inner radius ratio of $\text{1}\text{10}$.     

Ductile fracture of a pipe with a rectangular three-dimensional defect

A model is constructed to describe the ductile fracture of a pipe with a rectangular three-dimensional defect. Upper and lower bounds are obtained for the burst pressure. The first is calculated for a rectangular crack, while the second is calculated for an axisymmetric three-dimensional defect. It is shown that if the half-width of the defect b₀ is equal to 2(Rt_n)^1/2 — where R is the radius of the pipe and t_n is the net thickness of the pipe wall—then the defect can be regarded as axisymmetric. Calculated values of burst pressure are compared with literature data from full-scale tests of pipes. The results can be used to analyze actual defects in pipelines (pitting, etc.), as well as in conducting full- scale tests of pipes and pressure vessels.Translated from Problemy Prochnosti, No. 9, pp. 55–66, September, 1995.     

The performance of precursor-based estimators for rare event frequencies

Data on accident ‘precursors’ or ‘near misses’ can help in obtaining accurate estimators of accident frequencies when actual accident data is sparse. A variety of precursor-based estimators have been proposed in the literature. This paper presents results of a simulation study to assess the statistical performance of several such estimators, to help in determining which are the most suitable for use in practice.     

Computational study of a rarefied gas flow through a long circular pipe into vacuum

The paper presents an analysis of the non-linear rarefied gas flow through a circular pipe into vacuum. The main attention is given to the case of the large length to radius ratio. The problem is studied on the basis of the numerical solution of the S-model kinetic equation. Results are compared with the available DSMC data for short tubes as well as with the asymptotic solution corresponding to the infinitely long pipe.