Analytical evaluation of aircraft operational risks from runway rutting

Runway surface distortions such as rutting allow water to accumulate on the runway surface which may cause aircraft operational risks related to hydroplaning and loss of friction. This may increase the runway excursion risk during wet weather conditions. Several standards relating to airfield pavement maintenance have documented that rutting can cause safety hazards to aircrafts due to hydroplaning risk. This paper proposes an analytical approach to evaluate the hydroplaning potential for aircrafts due to the flooded ruts of a runway pavement and evaluate the operational risk. A finite element model is developed to simulate aircraft tyre hydroplaning under given set of operating conditions. By performing this evaluation for different rut depths, an assessment of the relative severity levels of different rut depths with respect to hydroplaning can be made. A numerical example is presented to illustrate the application of the procedure to evaluate operational risks to aircraft from runway rutting.     

论产品绿色设计

产品的绿色设计是通过产品的设计减少对环境的污染以实现社会和经济的可持续发展,目前国内对绿色设计的理解和运用仍然存在一定的困惑。产品绿色设计是一个系统性工程,地方官员强化绿色设计意识,企业增强绿色生产意识,设计师坚守绿色设计理念,消费者信守绿色生活信念,教育工作者坚持绿色教育,只有这样才能保证产品绿色设计得以推广和实现。     

Infrared-visible sum frequency generation investigation of Cu corrosion inhibition with benzotriazole

Infrared-visible sum frequency generation spectroscopy is used to investigate the corrosion inhibitor benzotriazole (BTAH) adsorbed on Cu(100) and Cu(111) in acidic solution. Potential-dependent in situ spectra indicate that the adsorbed molecule is the benzotriazole anion (BTA-) at all potentials investigated. The Cu(100) surface is shown to form an ordered adlayer at all potentials probed, while the Cu(111) face is shown to be disordered at negative potentials, but to order with applied positive potential. The ordered adlayer is shown to consist of the BTA- in two configurations, one coordinated to the surface and Cu+ ions in solution and the other coordinated only to the surface. The BTA- coordinated to Cu+ is shown to be more stable with respect to Cl- addition than BTA- coordinated to only the surface. This study demonstrates the viability of using sum frequency generation to study corrosion inhibition in situ.     

Scientometric Perspectives of the Analysis of Chemical Terminology

This paper is dedicated to the memory of Prof. Nalimov. The paper is to show some possibilities of bibliometric methods applied to Subject Index to “CHEMICAL ABSTRACT” (CA) and to Permuterm Subject Index to “SCIENCE CITATION INDEX”. This revised version was published online in June 2006 with corrections to the Cover Date. This revised version was published online in June 2006 with corrections to the Cover Date. This revised version was published online in June 2006 with corrections to the Cover Date.     

MVC模式的网络游戏可移植性研究

分析了由于网络游戏逻辑与网络游戏引擎的"紧耦合",使得可移植的跨游戏引擎的网络游戏实现困难的原因.提出了采用Model-View-Controller(MVC)设计模式设计可移植的跨不同游戏引擎的网络游戏平台体系结构方法,并对提出的网络游戏平台体系结构性能进行了测试评价,分析了新的体系结构的优点和不足.     

中国传统图案对现代礼品包装设计的启示

论述了中国传统图案如何运用到现代礼品包装设计中,如何结合现代工艺手段,使现代礼品包装充满文化底蕴和艺术性,满足人们的需求,同时,丰富现代包装设计的面貌,为平面设计带来新的形式.     

Analysis of the effect of pressure on compression moulding of UHMWPE

Ultra-high molecular weight polyethylene (UHMWPE) powder is effectively processed by compression moulding due to its very high melt viscosity. Compression moulding involves application of temperature and pressure as a function of time. The pressure applied during processing has a significant influence on the part properties. The effect of pressure applied during compression moulding was studied by moulding parts at different pressures. Increase in the applied pressure causes increase in the melting and recrystallization temperatures. An increase in the pressure applied at the melt temperature (140°C) from 7.8 MPa to 15.6 MPa caused the crystallinity to increase from 54% to 61%, the stiffness of the moulded part to increase from 257 MPa to 435 MPa and oxidative index to increase from 0.055 to 0.059. Further increase in the pressure applied at the melt to 23 MPa caused the crystallinity to fall to 49%, the modulus to reduce significantly to 302 MPa and the oxidative index to change to 0.063. Increase in the pressure applied at the recrystallization temperature (91°C) from 38 MPa to 78 MPa increased the crystallinity from 54% to 65%, increased the modulus from 257 MPa to 279 MPa and increased the oxidative index from 0.055 to 0.065. Further increase in the applied pressure to 97 MPa, caused the crystallinity to drop slightly to 61% the modulus to reduce to 269 MPa, and the oxidative index to reduce to 0.057. The experiments showed that for obtaining maximum crystallinity and stiffness, the applied pressure should be within a narrow range. The highest recrystallization pressure (97 MPa) indicated the formation of extended-chain crystals in addition to the chain-folded crystals. The change in pressure applied at the melt temperature had a significantly greater effect on Young's modulus, as compared to change in pressure applied at the recrystallization temperature. Fourier transform–infrared spectroscopy analysis of the samples moulded at different pressures revealed that the increase in crystallinity and stiffness was accompanied by increase in oxidation within the part. By filling the die in a nitrogen atmosphere instead of air, the oxidation level in the moulded parts was reduced by almost 60%, without adversely affecting the crystallinity and the modulus. © 1998 Chapman & Hall     

Using alloy to analyse a spatio-temporal access control model supporting delegation

Pervasive computing applications use the knowledge of the environment to provide better services and functionality to the end user. Access control for such applications needs to use contextual information. Towards this end, we proposed an access control model based on role-based access control that uses the environmental contexts time and location to determine whether a user can get access to some resource. The model also supports delegation which is important for dynamic applications where a user is unavailable and permissions may have to be transferred temporarily to another user/role in order to complete a specific task. Such a model typically has numerous features to support the requirements of various applications. The features may interact in subtle ways to produce conflicts. Here, we propose an automated approach using Alloy for detecting such conflicts. Alloy is supported by a software infrastructure that allows automated analysis of models and has been used to verify industrial applications. The results obtained from the analysis will enable the users of the model to make informed decisions.     

论企业家素质

企业家是以自己的洞察力和创造力发现和消除市场的不均衡性，善于抓住商机、占领和拓展市场，为企业赚取利润、更有效地利用生产要素，为社会创造财富的人，企业家在现代企业的生产经营活动中处于中位。在此对企业家的基本素质进行了初步的论述，这对于我国对培养就适应于市场经济条件下的科技、管理人才具有重要的现实意义。     

Accurately computing the optical pathlength difference for a michelson interferometer with minimal knowledge of the source spectrum

Astrometric measurements using stellar interferometry rely on precise measurement of the central white light fringe to accurately obtain the optical pathlength difference of incoming starlight to the two arms of the interferometer. One standard approach to stellar interferometry uses a channeled spectrum to determine phases at a number of different wavelengths that are then converted to the pathlength delay. When throughput is low these channels are broadened to improve the signal-to-noise ratio. Ultimately the ability to use monochromatic models and algorithms in each of the channels to extract phase becomes problematic and knowledge of the spectrum must be incorporated to achieve the accuracies required of the astrometric measurements. To accomplish this an optimization problem is posed to estimate simultaneously the pathlength delay and spectrum of the source. Moreover, the nature of the parameterization of the spectrum that is introduced circumvents the need to solve directly for these parameters so that the optimization problem reduces to a scalar problem in just the pathlength delay variable. A number of examples are given to show the robustness of the approach.     

The development of ‘green’ airports: Which factors influence willingness to pay for sustainability and intention to act? A structural and mediation model analysis

The study's purpose was to determine which factors influence a consumer's willingness to pay for sustainability and their intention to take action against climate change related to airports. An expanding body of literature relates to assessing whether consumers would be willing to pay for these ‘green’ practices in the aviation industry, such as biofuels or sustainable airport construction/renovations. While previous studies have experimentally examined these scenarios, we are aware of no prior research that has proposed and assessed a structural model related to determining which factors influence consumer's perspectives on ‘green’ airports. A sample of 722 eligible participants from the United States completed the study using Amazon's Mechanical Turk. We examined future time perspective, affect toward climate change, the perceived value of sustainability, and perceptions of climate change on the endogenous variables of willingness to pay for sustainability and intentions to take action against climate change. Six of the seven hypotheses proposed were supported. Affect, perceived value, and perceptions of climate change were all significant and positively related to willingness to pay, which was positively associated with intention to act. Two non-hypothesized paths, between perceived value and future time perspective, were also positively related to intention to act. The model explained 42% of the variance in willingness to pay and 66% in intention to act. These findings offer insights into what factors significantly influence these relationships as they relate to airports. Perceived value and perceptions of climate change had the largest effect sizes in the model and were significantly related to willingness to pay and intentions to act.     

Scope methodology for safety

The EXTENDED Assessment/Certification task of the ESPRIT project SCOPE is intended to address those issues of Software Assessment/Certification which are not directly covered by its BASIC Assessment/Certification Model. That is it aims to cover some aspects of ‘Fitness of Purpose’ of software products, but, being mindful of the advice emanating from the Legal Study, will not claim to cover all aspects. This may readily be appreciated too, by appreciating the plethora of techniques which are already available to, say, the safety community. The aim is to assess the impact of these techniques upon the SCOPE BASIC model, and to recomment adjustments if necessary.We intend to introduce some of those problems and techniques which may be of relevance to the extended certification task of SCOPE, though it should be borne in mind that the project ultimately has to demonstrate the feasibility of its approach to certification, and that it is not its purpose to develop new tools but rather to investigate, adapt and integrate existing tools to demonstrate the viability of the proposed approach. In the Appendix we introduce a new relativistic software reliability model.This paper is not intended to be complete, it is meant to provoke discussion and reports on progress so far.     

Investigating driving behaviour of older drivers with mild cognitive impairment using a portable driving simulator

While there is a large body of research indicating that individuals with moderate to severe dementia are unfit to drive, relatively little is known about the driving performance of older drivers with mild cognitive impairment (MCI). The aim of the current study was to examine the driving performance of older drivers with MCI on approach to intersections, and to investigate how their healthy counterparts perform on the same driving tasks using a portable driving simulator. Fourteen drivers with MCI and 14 age-matched healthy older drivers (aged 65–87 years) completed a 10-min simulator drive in an urban environment. The simulator drive consisted of stop-sign controlled and signal-controlled intersections. Drivers were required to stop at the stop-sign controlled intersections and to decide whether or not to proceed through a critical light change at the signal-controlled intersections. The specific performance measures included; approach speed, number of brake applications on approach to the intersection (either excessive or minimal), failure to comply with stop signs, and slower braking response times on approach to a critical light change. MCI patients in our sample performed more poorly than controls across a number of variables. However, because the trends failed to reach statistical significance it will be important to replicate the study using a larger sample to qualify whether the results can be generalised to the broader population.     

A practical heuristic for the group technology economic lot scheduling problem

Automated Guided Vehicle (AGV) systems are complex to design and to implement. Inefficiencies become difficult to avoid or even to control. This paper presents the theory behind a novel agent based AGV controller that aims to control the flow of AGVs in an effective manner and, therefore, overcome the inefficiencies that can be found in complex designs. Agents are simple entities that interact with other agents to produce an emergent behaviour that is not explicitly programmed into them. The AGV controller presented uses agents as traffic managers to allow access to points and segments in the guide path. Each agent has a rule base that it uses to assess the enquiries that it receives from an AGV. Each enquiry is evaluated only at the smallest possible part of the guide path rather than the entire guide path. AGVs are then able to allocate segments and points on their paths depending on the result of each enquiry. Simulation experiments were used to test the controller and an overview is presented.     

Impacts of climate change on coastal flood risk in England and Wales: 2030-2100

Coastal flood risk is a function of the probability of coastal flooding and the consequential damage. Scenarios of potential changes in coastal flood risk due to changes in climate, society and the economy over the twenty-first century have been analysed using a national-scale quantified flood risk analysis methodology. If it is assumed that there will be no adaptation to increasing coastal flood risk, the expected annual damage in England and Wales due to coastal flooding is predicted to increase from the current 0.5 billion pounds to between 1.0 pound and 13.5 billion pounds, depending on the scenario of climate and socio-economic change. The proportion of national flood risk that is attributable to coastal flooding is projected to increase from roughly 50% to between 60 and 70%. Scenarios of adaptation to increasing risk, by construction of coastal dikes or retreat from coastal floodplains, are analysed. These adaptations are shown to be able to reduce coastal flood risk to between 0.2 pounds and 0.8 billion pounds. The capital cost of the associated coastal engineering works is estimated to be between 12 pounds and 40 billion pounds. Non-structural measures to reduce risk can make a major contribution to reducing the cost and environmental impact of engineering measures.     

Correlating cell morphology and osteoid mineralization relative to strain profile for bone tissue engineering applications.

A number of bone tissue engineering strategies use porous three-dimensional scaffolds in combination with bioreactor regimes. The ability to understand cell behaviour relative to strain profile will allow for the effects of mechanical conditioning in bone tissue engineering to be realized and optimized. We have designed a model system to investigate the effects of strain profile on bone cell behaviour. This simplified model has been designed with a view to providing insight into the types of strain distribution occurring across a single pore of a scaffold subjected to perfusion-compression conditioning. Local strains were calculated at the surface of the pore model using finite-element analysis. Scanning electron microscopy was used in secondary electron mode to identify cell morphology within the pore relative to local strains, while backscattered electron detection in combination with X-ray microanalysis was used to identify calcium deposition. Morphology was altered according to the level of strain experienced by bone cells, where cells subjected to compressive strains (up to 0.61%) appeared extremely rounded while those experiencing zero and tensile strain (up to 0.81%) were well spread. Osteoid mineralization was similarly shown to be dose dependent with respect to substrate strain within the pore model, with the highest level of calcium deposition identified in the intermediate zones of tension/compression.