Cognitive and visual predictors of UFOV performance in older adults

Eighty two community dwelling older adults (52 females) aged 62–92 years (mean = 75) completed a battery of cognitive and visual tests selected to assess functions relevant to driving performance. These were visual acuity, contrast sensitivity, general mental competence (Mini Mental State Examination, MMSE), processing speed (Inspection Time, IT), crowding across the visual field (Proficiency of Peripheral Vision Processing, ProPerVis) and change detection (DriverScan). These six tasks provided predictor variables for performance on the Useful Field of View test (UFOV), a well validated test of fitness to drive that includes subtests for (i) processing speed; (ii) divided attention; and (iii) selective attention. Relative importance regression analyses confirmed that UFOV is sensitive to attentional and speed processes but suggested that subtest (i) primarily reflects visual acuity and contrast sensitivity; subtest (ii) is better explained by change detection and processing speed; and subtest (iii) predominantly reflects crowding and contrast sensitivity. Unexpectedly, given no evidence of substantial cognitive decline, MMSE contributed significantly to performance on the more complex subtests (ii) and (iii).     

Deformation and fracture of paper during the in-plane fracture toughness testing--Examination of the essential work of fracture method

The essential work of fracture (EWF) method is applied to various machine-made papers. The deforming and fracturing processes of the paper samples during testing is analyzed by means of the thermographic observation. Plastic deformation zone appears in three ways when deep double edge notched tension specimens are strained under in-plane stress: i.e. 1. type (i)--appearing through whole the ligament in a vague manner and developing into a circular (or oval) zone even before or at the maximum load point; 2. type (ii)--appearing from notch tip and amalgamating into a circular (or oval) zone after the maximum load point; and 3. type (iii)--appearing from notch tip and not amalgamating into a circular (or oval) zone until the sheet failure. Specimens with small ligament length (L) are likely to belong to type (i), while those with large L to type (ii) & (iii). Among these three types, type (i) fulfills the original assumption of the EWF method best in terms of the complete ligament yielding before crack initiation. Thus the specific essential work of fracture determined using the linear relation of type (i) should be correct, although the estimated work is a little smaller than that from the linear relation of type (ii) & (iii).     

Practical implementation of the medical exposure directive (97/43) in Luxembourg

The medical exposure Directive of 1984 was updated in 1997 (EURATOM 97/43) and should be implemented into national legislation before May 2000. Need for harmonisation exists in Europe, as differences in the application of ionising radiation exist throughout European countries and social mobility of the population is increasing. The context of the justification/optimisation process as well as specific characteristics of national health legislation and Social Security legislation and their impact on radiation protection of the patient, are presented. Existing differences in the justification process throughout Europe are: (i) prescribing process of the X ray examination, training of the prescriber, (ii) auto-referral; (iii) economic situation in the member states. The optimisation process is mainly sensitive to: (i) 'culture' of radiation protection in each national medical community; (ii) training; (iii) technical and clinical audits; (iv) quality assurance.     

Nitrogen contamination in the Yangtze river system, China

The data at 570 monitoring stations during 1990 were studied. The results indicate as follows: (i) the contents of nitrogen in the Yangtze mainstream has a raising trend from the upper reaches to the lower reaches; (ii) total nitrogen content at a lot of stations during the middle 1980s is 5-10 times more than that during the 1960s; (iii) seasonal variances of nitrogen content vary with watersheds; and (iv) the difference of nitrogen contamination level is related to the regional population and economic development.     

A framework for decision-making in investment alternatives selection

Investment alternatives selection involves a variety of criteria that should be evaluated to provide a solid basis for decision-making. Some prior research has proposed methodologies and frameworks to support such alternatives selection. However, many of them present intrinsic limitations related to their applicability and complexity. Thus, this paper presents a framework for decision-making concerning investment alternatives that are usually related to equipment selection for a manufacturing process, technology selection for product development, product portfolio selection, and production strategy selection, among others. The framework is based on a multi-criteria approach that considers three main criteria: (i) strategy, which considers company market competitiveness; (ii) quality, which considers client requirements; and (iii) economic aspects, considering the overall financial benefits of the investment. These criteria are evaluated with the support of well-known tools from traditional management engineering such as SWOT, QFD, NPV and Payback. The results obtained through the use of these tools are rated using the MAUT method. Two major contributions are offered by this framework: (i) the integration of three key criteria for decision-making that enables to obtain a balanced analysis of the investment alternatives and (ii) the intrinsic easy-to-implement characteristic of the framework – based on the use of traditional tools. The proposed framework was applied in a tailor-made furniture company to support a make-or-buy decision, and the obtained results are discussed.     

Computational modelling of final covers for uranium mill tailings impoundments

To properly design a final cover for uranium mill tailings impoundments the designer must attempt to find an effective geotechnical solution which addresses the radiological and non-radiological potential impact and prevents geochemical processes from occurring within the tailings. This paper presents a computer-based method for evaluating the performance of engineered final covers for the remediation of uranium mill tailings impoundments. Three hypothetical final covers were taken from scientific literature to investigate the proposed method: (i) a compacted clay liner (CCL); (ii) a composite liner (CL) and (iii) a capillary barrier (CB). The processes investigated: (i) the saturated hydraulic flux; (ii) the unsaturated hydraulic flux (exclusively for the capillary barrier) and (iii) the radon exhalation to the atmosphere. The computer programs utilised for the analyses are: (i) Hydrologic Evaluation of Landfill Performance (HELP); (ii) SEEP/W and (iii) RADON. The site considered for the development of the research presented herein was the uranium mill tailings impoundment located at the Brazilian city of Poços de Caldas, in the Minas Gerais State.     

Atomic-volume variations of α-Pu alloyed with Al, Ga, and Am from first-principles theory

First-principles methods are employed to calculate the ground-state atomic densities (or volumes) of α-Pu alloyed with Al, Ga, and Am. Three configurations for the alloying atom are considered. (i) It is located at the most open and energetically most favorably site. (ii) It is located at the least open site. (iii) It is randomly distributed within the α-Pu matrix. When alloyed with Al or Ga, α-Pu behaves similarly, it expands considerably for configurations (ii) and (iii), while for (i) only small changes of the density occur. Interestingly, for Am, the alloying effects are quite different from that of Al and Ga. Small expansion is noted for the ordered configurations (i) and (ii), whereas for the disordered (iii), only insignificant changes of the density take place. The bonding character is thus differently influenced in Pu by the addition of Al and Ga on one hand and Am on the other. This is consistent with the view that Al and Ga stabilize the δ over the α phase in Pu by a different mechanism than Am, as has been discussed in recent publications. The U.S. Government’s right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.     

Thermal–mechanical modelling of laminates with fire protection coating

This paper presents a modelling approach to analyse the protection provided by passive and intumescent surface coatings on glass fibre reinforced laminate substrates exposed to fire. The modelling involves a multi-stage analytical approach: (i) thermal analysis of heat transfer from the fire through the surface insulation coating, which includes decomposition and expansion in the case of an intumescent material; (ii) thermal–chemical analysis of heat transfer through the fibreglass laminate substrate (beneath the fire protective coating), including decomposition of the polymer matrix; and (iii) thermal–mechanical analysis of softening and failure of the laminate under in-plane tension or compression loading. The modelling approach is validated using experimental temperature and strength data from fire structural tests performed on woven glass–vinyl ester laminates insulated with passive (ceramic fibre mat) or organic intumescent surface coatings.     

Incremental path-independent integrals in inelastic and dynamic fracture mechanics

Certain incremental path-independent integrals, of relevance in the mechanics of fracture of elastic-plastic materials described by a classical flow theory of plasticity, are presented. Both quasi-static as well as dynamic fracture situations are considered. The topics discussed include: (i) incremental path-independent integrals that characterize the crack-tip fields in elastic-plastic materials; (ii) incremental integrals related to the incremental total potential energy difference; and (iii) the complementary or dual representations of these integrals. The use of these integrals is illustrated through some numerical examples. Comments are made on the utility of these integrals in postulating rational fracture criteria.     

On generation of horseshoe vortices by corrugated surfaces, surface roughnesses or pipe bends

This study is motivated by applications to near-wall shear flow (i) as a longitudinal wall shaping starts, (ii) around a surface obstacle, or (iii) through a pipe bend. All are shown to be governed, at relatively high flow rates, by essentially the same theoretical problem. This concerns three-dimensional nonlinear longitudinal vortex-like motion under a prescribed displacement which continues to increase with distance downstream. Symmetry-plane solutions are obtained mainly through forward marching computation followed by analysis of the far-downstream response. The behaviour far downstream is found to involve either a strengthening attachment or an increasing three-dimensional separation (lift-off) with no backflow.     

Organizational environment and performance of research groups—A typological analysis

In this paper an attempt is made to construct a typology of research units according to a set of organizational features and relate the resulting classification to a set of performance measures. The organizational features include (i) resources and facilities for research; (ii) Communication and transfer of new ideas; (iii) Planning and organization of research; and (iv) Social psychological environment for research. The performance measure include (i) General R&D effectiveness, which essentially connotes the quality dimension of research performance; (ii) Recognition of the work of the research unit by the scientific community; (iii) User-oriented effectiveness; and (iv) Administrative effectiveness (budget and schedule compliance). This study is based on the subset of empirical data on 220 research units collected in India for the third round of the UNESCO International Comparative Study on the Organization and Performance of Research Units (ICSOPRU). Twenty three measures of organizational environment, operationalized by multiple indicators, were chosen as discriminant criteria for the construction of the typology, using a classification computer programme SYSTIT (Systeme' de Typologie Iterative). The relationship between typology groupings and performance measures was analyzed through multiple correspondence analysis. This study brings out that resources and facilities for research are a necessary but not a sufficient condition of performance. The sufficiency condition implies a positive work environment, effective communication within and outside the research group and a conceptually exciting research programme.     

Some X-ray photoelectron spectroscopic measurements on Passivated Tin in some neutral media

Some ESCA measurements have been carried out on the anode film formed on BDH Sn foil by the potentiodynamic technique up to 2.5 V (SCE) in (i) phosphate buffer, pH 6.7, (ii) 0.1 M KCl, 0.1 M Na₂SO₄, pH 6.6, in order to identify the elements, and possibly also some compounds, present in the film. The results in phosphte buffer indicate the presence of: (i) Sn(II) and Sn(IV) oxides and hydroxides, (ii) tin phosphate species probably (HPO₄)^2?, (H₂PO₄)^?, and insoluble phosphate complexes and (iii) evidence is given for the formation of soluble Sn species containing OH or phosphates before the beginning of passivity. The results in chloride solutions indicate the presence in the anode film of Sn, O and Cl in various states of combination such as: (i) Sn(II) and Sn(IV) species (oxides, chlorides and some hydroxides, (ii)) adsorbed oxygen and water, and (iii) basic or oxysalts or complexes involving Sn, O, Cl, and K. The results in Na₂SO₄ solutions indicate the presence in the film of Sn, O, S, and Na in the form of: (i) Sn(II) and Sn(IV) oxides and hydroxides, (ii) Na₂SO₄, other un- identified S species, and possibly also traces of PbS (from traces of Pb present in the Sn foil), (iii) adsorbed oxygen and water, and (iv) basic or oxysalts or complexes involving Sn, Na, O, sulphate and other unidentified S species.     

Analysis of cracks in aging aircraft structures,with and without composite-patch repairs

In this paper, the problems of composite-patch repair of (i) center and edge-cracked panels loaded in the far-field; and (ii) cracks emanating from pin-loaded fastener holes, are examined in thorough detail. The effects of various non-dimensional design parameters on the reduction in the stress-intensity factors near the crack-tip are determined, and are presented in the form of design charts. Both analytical and numerical methods are employed in this study. In the analytical method, the cracked metallic plate was considered to be infinitely large, and the composite patch was modeled as a long orthotropic strip of finite height (in the direction perpendicular to the crack axis). Next, by using the Finite Element Alternating Method (FEAM), a more general analysis capability that can treat arbitrary shapes of the cracked metallic sheet, as well as of the composite patches, is developed. This general FEAM is applied to: (i) composite patch repairs of cracks emanating from loaded fastener holes (the MSD problem); (ii) composite patch repairs of semi-elliptical surface flaws in thick plates; and (iii) composite patch repairs of quarter-elliptical surface flaws emanating from fastener holes. Problem (i) is two-dimensional in nature while problems (ii) and (iii) are fully three-dimensional. In all these cases, the effects of various design parameters on the crack-tip (front) stress-intensity factors are fully discussed.     

On tandem stochastic networks with time-deteriorating product quality

We consider an n-site tandem stochastic production network where each product moves sequentially through the sites, and the product's quality deteriorates with its sojourn time in the system. At each site the product goes through two stages: the first stage is a processing operation with a generally-distributed random duration. This operation either does or does not conclude successfully; in the latter case, the operation is repeated immediately. Once the processing operation concludes successfully, the product goes through an inspection stage lasting a generally-distributed random duration. At the end of the inspection the product's state is determined as follows: either (i) it requires additional processing and moves forward to the next site; or (ii) it is found ‘good’ and exits the network with quality value depending on its total sojourn time in the system; or (iii) it is declared ‘failed’, discarded, and exits the network with zero quality value. Two scenarios are analysed: (i) a new product enters the system only after the preceding product has exited and (ii) the network is a tandem Jackson-type system. For each scenario, we construct both time-dependent and quality-dependent performance measures. In the case where the sites can be arranged in an arbitrary order, we derive easy to implement optimal index-type policies of ordering the sites so as to maximise the quality rate of the production network.     

Experimental studies on multicellular GFRP bridge deck panels under static and fatigue loading

This paper presents the experimental investigations carried out on hand lay-up prototype multicellular glass fibre reinforced polymer (GFRP) composite bridge deck panels under static and fatigue loading. Various sustainability aspects with regard to GFRP structural members were discussed. The aspects include (i) social development; (ii) environmental protection; and (iii) economic development. The GFRP material properties were evaluated by using (i) micromechanics; (ii) simplified composite micromechanics equations (Chamis); (iii) carpet plots; and (iv) equations proposed by Tsai–Hahn. GFRP members with various cross sections were tested to decide the better performance under flexural loading and found that GFRP with hollow section performs better. For the optimised cross-section dimensions, six multi-cellular GFRP composite bridge deck panels of size 1250 mm × 333 mm × 150 mm (l × b × d) were fabricated by hand lay-up process and tested for static and fatigue loading. It was observed from the experiment that during testing the bridge deck panel, no load shedding was observed even though the resin started cracking. At ultimate load, there was a loud cracking sound and the specimen load shedding occurred suddenly. Factor of safety for load and deflection was computed. From the fatigue experiments, it is observed that the percentage reduction in stiffness is approximately 12% for 500,000 cycles.     

Thermal analysis of poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogels

The influence of water on the physical properties of a hydrogel is important for understanding natural tissues and in designing synthetic materials to replace them. In this study, poly (2-hydroxyethyl methacrylate) (pHEMA) was used as a model system to understand how water interacts with the polymer of a hydrogel. Thermal analysis methods (thermogravimetric analysis coupled to mass spectrometry and differential scanning calorimetry) were used to determine: (i) the total water content of pHEMA gels; (ii) how this water was lost during heating; (iii) the relationship between water content of the gel and its glass transition temperature; and (iv) the behavior of the water in the gel on cooling. Previous researchers have invoked various models to describe the organization of water in a hydrogel. In this study, the simplest model which could explain all of the results from the different thermal analysis techniques was one which consisted of three classes of water: (i) hydration water in close proximity to the polymer; (ii) interstitial water in regions or cavities surrounded by polymer chains; and (iii) bulk water.     

Ordering policies under one time only discount and price sensitive demand

Purchase price reductions, even on a one-time-only basis, allow retailers the opportunity to lower their own selling prices, albeit temporarily, in an effort to increase sales. This results in not only additional revenues but also in extra inventory costs. The model presented in this paper examines such a cost/revenue tradeoff, through simultaneous determination of the most profitable: (i) stock level to be purchased by the retailer; (ii) discount level to be passed on to the customers; (iii) stock level qualifying for the retailer's discount; and (iv) time to initiate the discount. Numerical examples are included throughout to illustrate the main features of the model.     

Optimal facility location with multi-purpose trip making

We address the optimal location problem for two different types of service, designated as type-A and type-B, where some users may obtain both types of service in multi-purpose trips. We consider three user groups: (i) users of only the type-A service; (ii) users of only the type-B service; and (iii) users of both services in a single trip. We seek to locate three types of facilities: (i) type-A; (ii) type-B; and (iii) joint facilities that offer both services. We formulate a p-median-based model that minimizes the total travel distance and use it to investigate the effect of multi-purpose trip-makers on optimal facility types and locations. Examples are used to show that services tend to cluster in joint facilities, even when the proportion of multi-purpose behavior is small.     

Probabilistic prediction of high cycle fatigue reliability of high strength steel butt‐welded joints

The aim of this paper is to develop a probabilistic approach of high cycle fatigue (HCF) behaviour prediction of welded joints taking into account the surface modifications induced by welding and the post‐welding shot peening treatment. In this work, the HCF Crossland criterion has been used and adopted to the case of welded and shot peened welded parts, by taking into account the surface modifications which are classified as follows: (i) the compressive residual stresses, (ii) the surface work‐hardening, (iii) the geometrical irregularities and (iv) the superficial defects. The random effects due to the dispersions of: (i) the HCF Crossland criterion material characteristics (ii) the applied loading and (iii) the surface modifications parameters are introduced in the proposed model. The HCF reliability has been computed by using the ‘strength load’ method with Monte Carlo simulation. The reliability computation results lead to obtain interesting and useful iso‐probabilistic Crossland diagrams (PCD) for different welding and shot peening surface conditions. To validate the proposed method, the approach has been applied to a butt‐welded joint made of S550MC high strength steel (HSS). Four types of specimens are investigated: (i) base metal (BM), (ii) machined and grooved (MG) condition, (iii) As welded (AW) condition and (iv) as welded and shot peened (AWSP) condition. The comparison between the computed reliabilities and the experimental investigations reveals good agreement leading to validate the proposed approach. The effects of the different welded and post‐weld shot peened specimen's surface properties are analysed and discussed using the design of experiments (DoE) techniques.     

Supply chain resilience: role of complexities and strategies

This article introduces the relationship between complexities and proactive management practices in supply chain resilience, particularly due to global sourcing (GS) strategies. The main objectives of this paper are as follows: (i) explain the various aspects of GS rather than reporting the trends and implications described in the literature, (ii) view GS in terms of complexity theory and (iii) investigate the resilience of supply chain due to GS complexity and suggest strategies to overcome complexities. We propose a GS resilience framework for future researchers to analyse the impact of GS complexity factors on supply chain resilience with respect to three outcomes: (i) risk and innovation, (ii) benefit in terms of sales promotion and (iii) challenges and responsiveness. Based on the framework, this introductory article summarises the papers appear in this special issue. This article would be useful to researchers and practitioners to further explore the role of complexities, proactive management strategies on GS resilience.