Is it possible to check microcomponent coatings?

Optical microcomponents are increasingly used in laser optical systems because of their many and novel industrial applications. These components are coated in order to enhance their optical performance, but optical characterizations are very difficult due to the shapes and small size. Thus, to perform this kind of measurement, special devices are needed. It is difficult to check component optical responses after manufacturing. Thus a new method, developed by the French Atomic Energy and Alternative Energies Commission, is proposed to fill this gap.     

Is it wise to protect false targets?

The paper considers a system consisting of genuine elements and false targets that cannot be distinguished by the attacker's observation. The false targets can be destroyed with much less effort than the genuine elements. We show that even when an attacker cannot distinguish between the genuine elements and the false targets, in many cases it can enhance the attack efficiency using a double attack strategy in which it tries first to eliminate with minimal effort as many false targets as possible in the first attack and then distributes its entire remaining resource among all surviving targets in the second attack. The model for evaluating the system vulnerability in the double attack is suggested for a single genuine element, and multiple genuine elements configured in parallel or in series. This model assumes that in both attacks the attacking resource is distributed evenly among the attacked targets. The defender can optimize its limited resource distribution between deploying more false targets and protecting them better. The attacker can optimize its limited resource distribution between two attacks. The defense strategy is analyzed based on a two period minmax game. A numerical procedure is suggested that allows the defender to find the optimal resource distribution between deploying and protecting the false targets. The methodology of optimal attack and defense strategies analysis is demonstrated. It is shown that protecting the false targets may reduce the efficiency of the double attack strategy and make this strategy ineffective in situations with low contest intensity and few false targets.     

When is it feasible to model low discrete demand by a normal distribution?

Inventory control systems used in practice are quite often modeling the lead-time demand by a normal distribution. This may result in considerable errors when the real demand is low and discrete. For such demand, it is usually better to use a discrete demand distribution. However, this will increase the computational effort. A natural question is under what circumstances a normal approximation is feasible. This paper analyzes this question in a numerical study. Our study indicates that a normal approximation works reasonably well when the average lead-time demand is something like 10 or higher and the coefficient of variation is bounded by something like 2. The normal approximation works better for a high backorder cost or, equivalently, a high service level.     

On the influence of nanoparticles as addition to the A356 aluminum-alloy: Is it acting as a refining or strengthening mechanism?

The effect induced by adding nanoparticles to cast hypo-eutectic aluminum 7 % silicon alloys (A356) is continually reported to show enhanced mechanical properties. The experimental results show a strengthening effect associated with an increase in ductility and/or toughness, induced by adding nanoparticles. The aim of this work is to add a contribution towards understanding the strengthening effect observed in the nanoparticles-reinforced A356 alloy. This is done by calculating the conventional incremental summation of several strengthening mechanisms contributing to strengthening and reinforcement in composites. The results obtained by applying the mathematical calculations are compared with the experimental results reported in literature. Based on the mathematical approach, this work shows that the main strengthening mechanisms acting for metal matrix nano composites (MMNCs) are those contributing to the strengthening of the matrix. These result from contributions by Orowan strengthening and coefficient of thermal expansion (CTE) and elastic modulus (EM) mismatch.     

Is your valley as green as it should be? Incorporating economic development into environmental performance indicators

Sustainability rankings are receiving increasing attention by the academic and the policymaking communities because of their potential to influence environmental legislation and reshape competitive landscapes. Unfortunately, most of the indicators used to produce these rankings do not take into account economic development and tend to be biased in favor of richer countries. To circumvent this limitation, we develop a novel, rigorous and simple metric that ranks countries by their potential environmental performance relative to their wealth; in other words, by the degree of sustainability that a country should achieve, given its level of affluence. We apply our approach to measure the sustainability level of 15 developed economies with respect to the share of renewable energy sources in their electricity-generating portfolios. The resulting ranking produces changes in the perceived greenness of certain countries. If adopted, it would allow these countries to increase their bargaining power in international negotiations. It would also alter the pressure faced by their governments to implement or discontinue environmental policies such as feed-in tariffs. Although we applied it at the country level and in the context of renewable energy, the method has far-reaching implications and it can also be used to compare corporate sustainability levels.     

Which battery model to use?

The use of mobile devices like cell phones, navigation systems or laptop computers is limited by the lifetime of the included batteries. This lifetime depends naturally on the rate at which energy is consumed; however, it also depends on the usage pattern of the battery. Continuous drawing of a high current results in an excessive drop of residual capacity. However, during intervals with no or very small currents, batteries do recover to a certain extent. The usage pattern of a device can be well modelled with stochastic workload models. However, one still needs a battery model to describe the effects of the power consumption on the state of the battery. Over the years many different types of battery models have been developed for different application areas. In this study we give a detailed analysis of two well-known analytical models, the kinetic battery model (KiBaM) and the so-called diffusion model. We show that the KiBaM is actually an approximation of the more complex diffusion model; this was not known previously. Furthermore, we tested the suitability of these models for performance evaluation purposes, and found that both models are well suited for doing battery lifetime predictions. However, one should not draw conclusions on what is the best usage pattern based on only a few workload traces.     

Is life what we make of it?

Although astrobiological or SETI detections are possible, actual invasions of sentient extra-terrestrials or plagues of escaped alien microbes are unlikely. Therefore, an anthropological perspective on the question suggests that in the event of a detection, the vast majority of humanity will be dealing not with extra-terrestrial life itself (whether intelligent or not, local or distant), but with human perceptions and representations of that alien life. These will, inevitably, derive from the powerful influences of culture and individual psychology, as well as from science. It may even be argued that in most detection scenarios, the scientific data (and debates about their interpretation) will be nigh-irrelevant to the unfolding of international public reaction. 'Extra-terrestrial life' will, in short, go wild. From this premise, some key questions emerge, including: what can scientists reasonably do to prepare, and what should their responsibilities be, particularly with respect to information dissemination and public discussions about policy? Then, moving beyond the level of immediate practicalities, we might also ask some more anthropological questions: what are the cultural substrates underneath the inquiries of Western science into extra-terrestrial life? In particular, what are the stories we have been told about discovery of rare life, and about contact with other beings, and do these stories really mean what we think they do? Might a closer look at those narratives help us gain perspective on the quest to find extra-terrestrial life, and on our quest to prepare for the consequences of detection?     

Is it useful to assess annual effective doses that are less than 100 mSv?

Questions such as 'How small is small?' and 'How low is low enough?' have long plagued radiation dosimetrists and risk management personnel. Unfortunately, our knowledge about the biological effects of low levels of ionising radiation is scarce and uncertain. If we look to the results of epidemiological studies, we find that it is not easy to arrive at firm conclusions. However, some current radiobiological experiments using microbeams of various radiations, along with improved theoretical models of radiation action, may shed new light on the effects of low levels of ionising radiation. What shall we do in the meantime? Both of our debaters agree that monitoring of radiation workers is necessary, yet careful consideration must be given to the rationale for providing personal monitoring. There is no question that we have done a good job of protecting radiation workers for many years, but we also must be aware of the many implications of our efforts.     

Fatigue in Rotating Equipment: Is it HCF or LCF?

This article discusses practical differences between high-cycle fatigue and low-cycle fatigue at relatively lower temperatures in rotating equipment and the equipment attached to it. Methods to identify the failure mode are discussed so proper prevention measures can be put in place to prevent future occurrences. Examples of typical components are provided to show the methods in action.     

Driving avoidance by older adults: Is it always self-regulation?

Self-regulation shows promise as a means by which older adults can continue to drive at some level without having to stop altogether. Self-regulation is generally described as the process of modifying or adjusting one's driving patterns by driving less or intentionally avoiding driving situations considered to be challenging, typically in response to an awareness that driving skills have declined. However, most studies asking older adults whether they avoid certain driving situations or have reduced the amount of driving they do under certain circumstances have not delved deeper into the motivations for such avoidance or driving reduction. There are many reasons for modifying driving that have nothing to do with self-regulation, such as no longer needing to take trips at certain times of day because of changes in preferences or lifestyles. The purpose of this study was to examine self-regulatory practices among older adults at multiple levels of driver performance and decision making, taking into account the specific motivations for avoiding particular driving situations or engaging in other driving practices. Study participants completed a computer-based questionnaire on driving self-regulation. Results suggest that self-regulation is a complex process that cannot be defined simply by the reported driving modifications made by drivers. Understanding the motivations for these behaviors is necessary and the study showed that they are varied and differ considerably across driving situations. Reasons for driving avoidance or other practices were often more closely related to lifestyle or preferences than to self-regulation. Based on these findings, three distinct groups were identified with regard to whether and for what reasons participants modified their driving.     

Has the time come to use near-infrared spectroscopy as a routine clinical tool in preterm infants undergoing intensive care?

Several instruments implementing spatially resolved near-infrared spectroscopy (NIRS) to monitor tissue oxygenation are now approved for clinical use. The neonatal brain is readily assessible by NIRS and neurodevelopmental impairment is common in children who were in need of intensive care during the neonatal period. It is likely that an important part of the burden of this handicap is due to brain injury induced by hypoxia-ischaemia during intensive care. In particular, this is true for infants born extremely preterm. Thus, monitoring of cerebral oxygenation has considerable potential benefit in this group. The benefit, however, should be weighed against the disturbance to the infant, against the limitations imposed on clinical care and against costs. The ultimate way of demonstrating the 'added value' is by a randomized controlled trial. Cerebral oximetry must reduce the risk of a clinically relevant endpoint, such as death or neurodevelopmental handicap. We estimate that such a trial should recruit about 4000 infants to have the power to detect a reduction in brain injury by one-fifth. This illustrates the formidable task of providing first-grade evidence for the clinical value of diagnostic methods. Is it a window of opportunity for the establishment of a rational basis before another technology is added to an already overly complex newborn intensive care?     

Arteriovenous fistula for the 80 years and older patients on hemodialysis: Is it worth it?

Over the last years, the proportion of patients older than 80 years with end‐stage renal disease has been constantly growing. Arteriovenous fistula (AVF) is known as the best vascular access for hemodialysis, but evidence for its added value is lacking for elderly. We retrospectively identified new vascular access (AVF and central venous catheter) created or installed between June 2005 and June 2008 in patients 80 years and older and in patients between 50 and 60 years. For every new AVF, we calculated primary failure, primary and secondary patency durations. Fifty‐five and 57 patients had a new vascular access in the >80 years old and 50 to 60 years old groups. Among these, 25 and 41 were new AVF in the older and younger groups. Primary failure was more frequent in elderly than in the younger (40% vs. 17%, P = 0.04). Primary patency was not significantly different in both groups (P = 0.06). Secondary patency was shorter in elderly (P = 0.005). Among the older group, the presence of an AVF was not associated with a difference in mortality (46% vs. 60%, P = 0.28), whereas there was a lower mortality in the younger group with AVF (12% vs. 43% P = 0.008). These results indicate lower patency duration in very elderly patients compared to middle‐aged patients. Without leading to the exclusion of patients over 80 years old for AVF creation, it might reinforce the need of a careful selection and evaluation in this population prior to referral.     

Is road safety management linked to road safety performance?

This research aims to explore the relationship between road safety management and road safety performance at country level. For that purpose, an appropriate theoretical framework is selected, namely the ‘SUNflower’ pyramid, which describes road safety management systems in terms of a five-level hierarchy: (i) structure and culture, (ii) programmes and measures, (iii) ‘intermediate’ outcomes’ – safety performance indicators (SPIs), (iv) final outcomes – fatalities and injuries, and (v) social costs. For each layer of the pyramid, a composite indicator is implemented, on the basis of data for 30 European countries. Especially as regards road safety management indicators, these are estimated on the basis of Categorical Principal Component Analysis upon the responses of a dedicated road safety management questionnaire, jointly created and dispatched by the ETSC/PIN group and the ‘DaCoTA’ research project. Then, quasi-Poisson models and Beta regression models are developed for linking road safety management indicators and other indicators (i.e. background characteristics, SPIs) with road safety performance. In this context, different indicators of road safety performance are explored: mortality and fatality rates, percentage reduction in fatalities over a given period, a composite indicator of road safety final outcomes, and a composite indicator of ‘intermediate’ outcomes (SPIs). The results of the analyses suggest that road safety management can be described on the basis of three composite indicators: “vision and strategy”, “budget, evaluation and reporting”, and “measurement of road user attitudes and behaviours”. Moreover, no direct statistical relationship could be established between road safety management indicators and final outcomes. However, a statistical relationship was found between road safety management and ‘intermediate’ outcomes, which were in turn found to affect ‘final’ outcomes, confirming the SUNflower approach on the consecutive effect of each layer.     

Is there ferromagnetic to spin-glass transition in PdAuFe alloys?

Electrical resistivity studies on several (Pd_1–x Au _x )_99.93Fe_0.07 alloys between 25 mK and 1 K are reported. The experiments reveal interesting features of the impurity spin polarization with the addition of Au atoms to pure PdFe_0.07 alloy. Forx<0.28 the ternary alloys exhibit a familiarT ² dependence for belowT _c , indicative of complex magnetic behavior. For still higher Au concentrations, resistivity maxima occur in these alloys, reflective of short-range magnetic ordering. Arguments are presented to show that this is strongly suggestive of spin-glass-type freezing at lower temperatures, as is observed in many canonical metallic spin-glasses.