Past, present and future in UK aerospace

The account which follows covers developments in the aircraft industry at Filton over the last forty to fifty years and future prospects.     

制冷剂的过去、现状和未来

回顾了制冷剂发展的三个历史阶段,综述了适应环保需要的国外制冷剂现状和使用中的主要技术问题,探讨了制冷剂未来发展趋势以及所应面对的几个问题,最后提出了相应的对策建议。     

Graphene based materials: Past, present and future

Graphene, a two dimensional monoatomic thick building block of a carbon allotrope, has emerged as an exotic material of the 21st century, and received world-wide attention due to its exceptional charge transport, thermal, optical, and mechanical properties. Graphene and its derivatives are being studied in nearly every field of science and engineering. Recent progress has shown that the graphene-based materials can have a profound impact on electronic and optoelectronic devices, chemical sensors, nanocomposites and energy storage. The aim of this review article is to provide a comprehensive scientific progress of graphene to date and evaluate its future perspective. Various synthesis processes of single layer graphene, graphene nanoribbons, chemically derived graphene, and graphene-based polymer and nano particle composites are reviewed. Their structural, thermal, optical, and electrical properties were also discussed along with their potential applications. The article concludes with a brief discussion on the impact of graphene and related materials on the environment, its toxicological effects and its future prospects in this rapidly emerging field.     

Phase-change optical recording: Past, present, future

We discuss specific features of Te-based compounds that made them the best materials for the phase-change data storage. It is demonstrated that the phase-change recording is due to a switch of Ge atoms between octahedral and tetrahedral symmetry positions within the Te face-centered cubic lattice. It is this nature of the transition that makes the Te-based media fast and stable. The driving force for this transition is also discussed. The chapter is concluded by introduction of a concept of the super-resolution near-field structure (super-RENS) disc that allows to reduce a bit size well below the diffraction limit and makes 100 GB/disc storage a reality.     

Finite-volume micromechanics of periodic materials: Past,present and future

The finite-volume method is now a well-established tool in the numerical engineering community for simulation of a wide range of problems in fluid and solid mechanics. Its acceptance by the mechanics of heterogeneous media community, however, continues to be slow, often characterized by confusion with the finite-element method or so-called higher-order theories. Herein, we provide a brief historical perspective on the evolution of this important technique in the fluid mechanics community, its transition to the solution of solid mechanics boundary-value problems initiated in Europe in 1988, and the recent developments aimed at the solution of unit cell problems of periodic heterogeneous media. The differences and similarities with the finite-element method are highlighted, and the resulting tangible advantages of the finite-volume technique discussed and illustrated. Finally, our most recent results in this area are presented which demonstrate the method’s capability of solving unit cell problems with complex architectures in a variety of settings and applications, while revealing undocumented effects of interest in the development of new material microstructures with targeted response. Recent attempts to develop alternative versions of this technique are also discussed, together with our ongoing work to generalize the finite-volume micromechanics approach in order to further enhance its predictive capabilities and efficiency.     

Consideration of durability of concrete structures: Past, present, and future

The paper expresses durability in terms of the expected conditions of exposure as well as of the specified or traditional service life of structure. A brief review of deleterious actions is given. Consideration of durability means how ensuring durability is viewed by designers, and not detailed advice or rules. Thus, the paper reviews the past attitude, which relied on providing strong concrete, it being believed that durability was concomitant with strength. Changes in the properties of cement, in that, with the ‘new’ cements, the same strength as specified heretofore could be achieved at a higher water-cement ratio resulted in structures with a distinctly reduced durability. This led to a re-consideration of mix design procedures, so that both strength and durability are now explicity considered. The future approach has to rely on the use of a range of cementitious materials and admixtures and on a meticulous performance of all operations from batching to curing.     

Theory of defects in Si and Ge: Past, present and recent developments

Over the past few decades, considerable progress has been achieved in the theoretical predictions of a wide range of properties of defects in semiconductors. In addition to structures, energetics, spin and charge densities, theory now routinely predicts accurate vibrational properties of defects, and thus connects to the optical characterization of light impurities. However, the positions of gap levels have yet to be predicted with systemically reliable accuracy. Today, supercells much larger than in the past are being used to describe defect centers from first principles. Systems large enough to study the dynamics of extended defects can be handled near the first-principles level. This paper contains a brief review of the key developments that have rendered theory quantitatively useful to experimentalists and an overview of the current ‘state-of-the-art’ and ongoing developments. Some of the remaining challenges are discussed, with examples in Si and Ge.     

Past, present and future precipitation in the Middle East: insights from models and observations

Anthropogenic changes in precipitation pose a serious threat to society-particularly in regions such as the Middle East that already face serious water shortages. However, climate model projections of regional precipitation remain highly uncertain. Moreover, standard resolution climate models have particular difficulty representing precipitation in the Middle East, which is modulated by complex topography, inland water bodies and proximity to the Mediterranean Sea. Here we compare precipitation changes over the twenty-first century against both millennial variability during the Holocene and interannual variability in the present day. In order to assess the climate model and to make consistent comparisons, this study uses new regional climate model simulations of the past, present and future in conjunction with proxy and historical observations. We show that the pattern of precipitation change within Europe and the Middle East projected by the end of the twenty-first century has some similarities to that which occurred during the Holocene. In both cases, a poleward shift of the North Atlantic storm track and a weakening of the Mediterranean storm track appear to cause decreased winter rainfall in southern Europe and the Middle East and increased rainfall further north. In contrast, on an interannual time scale, anomalously dry seasons in the Middle East are associated with a strengthening and focusing of the storm track in the north Mediterranean and hence wet conditions throughout southern Europe.     

Design of oral drug delivery systems - Past, present and future

This paper reviews the past and the present thinking about peroral delivery research and development and how future approaches may be significantly different, both qualitatively and quantitatively. The future should involve the use of comprehensive models capable of incorporating physico-chemical data and biological information such as gastrointestinal flow, how and where drug absorption occurs, and whether and where metabolism of the drug occurs during gastrointestinal transit. Special challenges would involve the use of such models in research protocols in the optimization of drug delivery systems.     

极地钢铁材料的腐蚀与防护面临新挑战

随着极地的开发和利用,其所需的极地钢铁材料的腐蚀与防护问题越来越受到研究者的关注。本文以传统海洋环境腐蚀分区为参照,对极地特色的腐蚀环境进行了系统的分析,并将其归纳整理为极地大气区、极地冰水磨蚀区、极地海洋全浸区、极地海底泥土区等4个腐蚀区域。在对极地钢铁材料腐蚀与防护的研究进展进行梳理的基础上,从合金化、涂层技术和阴极保护技术3个方面介绍了极地钢铁材料的防护技术,并指出了极地钢铁材料未来研究的方向。     

Engineering nanoparticles for targeting rheumatoid arthritis: Past,present, and future trends

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by synovial joint inflammation and cartilage and bone tissue destruction. Although there exist some treatment strategies for RA, they are not completely safe and effective. Therefore, it is important to develop and test new drugs for RA that specifically target inflamed/swollen joints and simultaneously attenuate other possible damages to healthy tissues. Nanotechnology can be a good alternative to consider when envisioning precise medication for treating RA. Through the use of nanoparticles, it is possible to increase bioavailability and bioactivity of therapeutics and enable selective targeting to damaged joints. Herein, recent studies using nanoparticles for the treatment of RA, namely with liposomes, polymeric nanoparticles, dendrimers, and metallic nanoparticles, have been reviewed. These therapeutic strategies have shown great promise in improving the treatment over that by traditional drugs. The results of these studies confirm that feasibility of the use of nanoparticles is mainly due to their biocompatibility, low toxicity, controlled release, and selective drug delivery to inflamed tissues in animal RA models. Therefore, it is possible to claim that nanotechnology will, in the near future, play a crucial role in advanced treatments and patient-specific therapies for human diseases such as RA.

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Past,present and future of Industry 4.0 - a systematic literature review and research agenda proposal

Over the last few years, the fourth industrial revolution has attracted more and more attentions all around the world. In the current literature, there is still a lack of efforts to systematically review the state of the art of this new industrial revolution wave. The aim of this study is to address this gap by investigating the academic progresses in Industry 4.0. A systematic literature review was carried out to analyse the academic articles within the Industry 4.0 topic that were published online until the end of June 2016. In this paper, the obtained results from both the general data analysis of included papers (e.g. relevant journals, their subject areas and categories, conferences, keywords) and the specific data analysis corresponding to four research sub-questions are illustrated and discussed. These results not only summarise the current research activities (e.g. main research directions, applied standards, employed software and hardware), but also indicate existing deficiencies and potential research directions through proposing a research agenda. Findings of this review can be used as the basis for future research in Industry 4.0 and related topics.     

The inelastic mean free path of electrons. Past and present research

The inelastic mean free path (IMFP) is a fundamental material parameter. Presently the IMFPs calculated by the TPP-2M predictive formula (NIST SRD 71) are generally used. Elastic peak electron spectroscopy (EPES) is proved to be adequate for experimental determination of the IMFP denoted by λ_e. λ_e is smaller then λ_i (TPP-2M) values, due to surface losses, characterized by the SEP (surface excitation) P_se material parameter. The present research is focused on the experimental determination of P_se based on Tanuma's work. The Tanuma factor f_sT is the ratio of experimental I_e and calculated I_c elastic peak intensities I_e(E)/I_c(E). The detection angle dependent I_c is proportional to ΔΩ, the solid angle of detection. The angular I_c(E,ΔΩ,α_d) was calculated applying the EPESWIN software of Jablonski. In our work, experimental data of Goto were analysed for Si and Ni. Recent angularly resolved AREPES results of Jablonski and Zemek were quantified by fitting them at the 42° CMA (cylindrical mirror analyser) angle to absolute data of Goto and applying f_sT. The models and SEP material parameters published by Werner et al., Ding et al., Kwei et al., Jablonski-Zemek and Nagatomi-Goto (Ni) and our data obtained by modifying Chen's data (Si) have been tested. The best approach was obtained using data of Werner for Si, and data of Nagatomi for Ni. The SEP corrected IMFPs λ_eco were deduced. The EPES SEP parameters were valid for AREPES by averaging over α_d = 35-70°. EPES spectra are quantified by applying the backscattering yield.     

Industrial Radiology,Past, Present and Future

A new model for sulphur sensitization has been developed. It is based on the surface double layer which has previously been shown to occur in silver halides. The charge present in this double layer causes the energy bands to bend downward or upward according to whether silver sulphide is present on the crystal surface or not. Where silver sulphide is not in contact with the surface the bands bend upward, thus impeding the motion of photo-electrons towards the surface. Conversely in points where silver sulphide is adsorbed onto the Srystal surface, the bands bend downwards, thus yielding an attracting force driving the photoelectron towards the silver sulphide speck. The bending of the bands may have the additional effect of increasing the lifetime of electrons in traps which are near to a silver sulphide Speck, thus holding the trapped electron for a long enough time as to allow the “ionic step” to take place. Our experimental results as well as others reported in the literature are explained with this model.     

Remote-sensing reflectance in the Beaufort and Chukchi seas: observations and models

Two semianalytical remote-sensing reflectance models were evaluated and validated by use of bio-optical data collected in the Beaufort and Chukchi seas. Both models were efficient at retrieving chlorophyll concentration, phytoplankton absorption coefficients,and particulate backscattering coefficients. In contrast, they were not accurate in predicting an absorption coefficient for colored dissolved organic matter plus nonpigmented particulates. The poor model performance is attributed to the high variability in the concentrations of these colored materials. A chlorophyll-dependent reflectance model was also assessed, and it proved to be highly successful in reproducing measured reflectance spetra. A four-component, case 2 model with mean absorption spectra for phytoplankton, soluble materials, and nonpigmented particulates was employed in Hydrolight radiative-transfer model simulations. The remote sensing reflectance spectra simulated inthe radiative-transfer model were in excellent agreement with field data. The similarity between the model and the measurement confirms the accuracy of the underlying bio-optical relationships and underscores the utility of modeling for better understanding of the variability of ocean color observations. The latest SeaWiFS algorithm (OC4V4) overestimated chlorophyll by approximately 1.5 fold across most of the observed range of biomass (0.07-9 mg chlorophyll m(-3)). Regionally tuned algorithms explained > 93% of the variability in the surface chlorophyll concentration.     

Pliocene palaeoceanography of the Arctic Ocean and subarctic seas

The Pliocene is important in the geological evolution of the high northern latitudes. It marks the transition from restricted local- to extensive regional-scale glaciations on the circum-Arctic continents between 3.6 and 2.4Ma. Since the Arctic Ocean is an almost land-locked basin, tectonic activity and sea-level fluctuations controlled the geometry of ocean gateways and continental drainage systems, and exerted a major influence on the formation of continental ice sheets, the distribution of river run-off, and the circulation and water mass characteristics in the Arctic Ocean. The effect of a water mass exchange restricted to the Bering and Fram Straits on the oceanography is unknown, but modelling experiments suggest that this must have influenced the Atlantic meridional overturning circulation. Cold conditions associated with perennial sea-ice cover might have prevailed in the central Arctic Ocean throughout the Pliocene, whereas colder periods alternated with warmer seasonally ice-free periods in the marginal areas. The most pronounced oceanographic change occurred in the Mid-Pliocene when the circulation through the Bering Strait reversed and low-salinity waters increasingly flowed from the North Pacific into the Arctic Ocean. The excess freshwater supply might have facilitated sea-ice formation and contributed to a decrease in the Atlantic overturning circulation.