Chiral Au₂₅ nanospheres and nanorods: synthesis and insight into the origin of chirality

Chirality in nanoparticles is an intriguing phenomenon. Herein, we have devised a well-defined gold nanoparticle system for investigating the origin of chirality in nanoparticles. We have designed chiral thiols (R- and S-isomers) and synthesized chiral gold nanoparticles composed of 25 gold atoms and 18 ligands, referred to as Au(25)(pet)(18), where pet represents chirally modified phenylethylthiolate -SCH(2)CH(CH(3))Ph at the 2-position. These optically active nanoparticles are close analogues of the optically nonactive phenylethylthioalte-capped Au(25)(pet)(18) nanoparticles, and the latter's crystal structure is known. On the basis of the atomic and electronic structures of these well-defined Au(25) nanoparticles, we have explicitly revealed that the ligands and surface gold atoms of Au(25)(pet)(18) play a critical role in effecting the circular dichroism responses from the nanoparticles. Similar effects are also observed in chiral Au(25) rods. The mixing of electronic states of ligands with those of surface gold atoms constitutes the fundamental origin of chirality in such nanoparticles.     

Computational fluid–structure interaction: methods and application to a total cavopulmonary connection

Note

Computational fluid–structure interaction: methods and application to a total cavopulmonary connection     

Iron oxide nanoparticles–cellulose: a comprehensive insight on nanoclusters formation

Journal of Materials Science - Due to unique nanoscale properties, as superparamagnetism, iron oxide nanoparticles (IONPs) hybridized with cellulosic matrixes are an attractive material for...     

Oblique penetration of a rigid projectile into a thick elastic–plastic target: theory and experiment

A model of oblique penetration of a rigid projectile into a thick elastic–plastic target has been developed (Roisman et al., Int J Impact Engng 1997; 19: 769–95) which incorporates stress-free boundary conditions at the rear surface of the target. The main objective of the present work is to validate the theoretical model by comparison with new experimental results for normal and oblique penetration of a rigid projectile into a thick plate of Al 6061-T651. Good agreement between theory and experiment is exhibited for the projectile residual velocity and the crater shape.     

The individual author’s publication–citation process: theory and practice

The model proposed by Burrell (Information Processing and Management 28:637–645, 1992, Journal of Informetrics 1:16–25, 2007a) to describe the way that an individual author’s publication/citation career develops in time is investigated further, the aim being to describe in more detail the form of the citation distribution and the way it evolves over time. Both relative and actual frequency distributions are considered. Theoretical aspects are developed analytically and graphically and then illustrated using small empirical data sets relating to some well-known informetrics scholars. Perhaps surprisingly, it is found that the distribution may well be approximated in some cases by a simple geometric distribution.     

Telescopic and panoramic views of library and information science research 2011–2018: a comparison of four weighting schemes for author co-citation analysis

Scientometrics - This study explores weighted author co-citation analysis (ACA) through a comparison of results from four weighted citation counting methods. The data set used comprises full-text...     

Practitioners’ perceptions of the Brazilian environmental impact assessment system: results from a survey

Practitioners play a key role in implementing environmental impact assessment (EIA) policies. Gauging their perception can help in designing legislation or regulation reforms and signals what needs more attention in research. The Brazilian EIA system is under review by lawmakers, but there is scant information about the views of professionals. A survey was conducted to inquiry on practitioners’ perception of the Brazilian EIA system regarding: (1) quality of the process, (2) quality of the environmental impact studies (EIS), and (3) proposals to change the system. Four hundred and fourteen professionals participated in an online survey responding to 44 questions. Results show positive perceptions about some aspects of current practice, but there is a clear predominance of negative appraisal both about the quality of the process and the quality of EIS. The poorest practices are the consideration of cumulative impacts and determination of impact significance. As for proposals to change the system, respondents defend the continuity of specific characteristics of the Brazilian system. Essentially, practitioners are calling for incremental changes that do not require any modification in the legislation.     

Pretreatment methods for gasification of biomass and Fischer–Tropsch crude production integrated with a pulp and paper mill

In this paper, the influence on the system performance and greenhouse gas (GHG) emissions of different biomass pretreatment methods before gasification and Fischer–Tropsch (FT) crude production was evaluated. Entrained flow gasification has the benefit of producing a practically tar-free synthesis gas with nearly complete carbon conversion. This gasifier type requires a relatively dry fuel, with small particle size, at high pressure. The size can be acquired by milling, which is energy intensive and feeding is challenging. Torrefaction of biomass facilitates milling; it thus requires less electricity, however, the torrefaction process requires heat. Pyrolysis decomposes the biomass into gaseous, liquid, and solid parts, respectively. This further makes feeding easier, but comes with a greater heat demand than torrefaction. The impact of the different pretreatment methods on the overall energy system has been evaluated using process integration methodology. The results show that the excess heat from an FT process with a biomass input of 300 MW_HHV can replace the bark boiler in a large chemical pulp and paper mill, producing 350,000 tonnes of bleached paperboard annually. With the preconditions given for this study, thermal pretreatment of biomass may be beneficial in terms of wood-to-FT crude efficiency, with efficiencies up to 68 %, assuming 40 % electrical efficiency. Pretreatment using pyrolysis performed the best in regards to GHG emissions, if CO₂ from acid gas removal was vented, while milling, with an annual reduction of around 700,000 tonnes of CO₂,_eq, had the best results if the CO₂ was captured and sequestrated.     

Renewable energy research 1995–2009: a case study of wind power research in EU, Spain, Germany and Denmark

The paper reports the developments and citation patterns over three time periods of research on Renewable Energy generation and Wind Power 1995–2011 in EU, Spain, Germany and Denmark. Analyses are based on Web of Science and incorporate journal articles as well as conference proceeding papers. Scientometric indicators include publication collaboration ratios, top-player distribution as well as citedness and correspondence analyses of citing publications, relative citation impact, distributions of top-cited as well as top-citing institutions and publication sources and cluster analysis of citing title terms to map knowledge export areas. Findings show an increase in citation impact for Renewable Energy and Wind Power research albeit hampered by scarcely cited conference papers. Although EU maintains its global top position in producing Renewable Energy and Wind Power research the developments of EU and German world shares as well as citation impact are negative during the most recent 7 year period. During the same time the citation impact of Spain and Denmark increase and place both nations among the top-ranking countries in Wind Power research. Spain is the only EU country that increases its world production share from 2000. China is currently ranked three after EU and USA in research output, however with a very low citation impact. Spain, Denmark and Germany each demonstrates distinct collaboration patterns and publication source and citation distribution profiles. More than half the citations to EU Wind Power research are EU-self citations. An expected intensified EU collaboration in the Wind Energy field does not come about. The most productive research institutions in Denmark and Spain are also the most cited ones.     

Stimulus–response compatibility and affective computing: a review

Affective computing, a human-factors effort to investigate the merits of emotions while people are working with human–computer interfaces, is gaining momentum. Measures to quantify affect (or its influences) range from EEG, to measurements of autonomic nervous system responses (e.g., heart rate, blood pressure), to less objective self-reports. Here we claim that simple response-time measurements may be a viable alternative to measure (indirectly) the effects of affect on performance by providing a review of experimental paradigms and associated models of human information processing. In particular, we focus on stimulus–response compatibility paradigms that have provided important insights for human-factors research, for instance regarding the important role of the spatial layout of interface design on the efficiency of human task performance, to show that these paradigms can also be applied to investigate the role of affect in human–computer interaction.     

Solid-state cold spraying of FeCoCrNiMn high-entropy alloy:an insight into microstructure evolution and oxidation behavior at 700-900℃

About 3 mm thick five-element equimolar high-entropy alloy(HEA) FeCoCrNiMn was successfully deposited by solid-state cold spraying(CS).The high-temperature oxidation behavior of the CSed HEA was investigated at 700-900℃.Heat treatment was performed on the CSed HEA before oxidation to heal the incomplete interfaces between the deposited particles.Results show that the microstructure of the CSed HEA is characterized by grain refinement and abundant interparticle incomplete interfaces.Post-spray heat treatment promotes recrystallization and grain growth in the CSed HEA.After oxidation testing,the oxide scales are composed of multi-layers:a Mn₂O₃(or Mn₃O₄) outer layer,a Mn-Cr spinel intermediate layer and a Cr₂O₃ inner layer.The CSed HEA exhibits higher parabolic rate constants and more favorable internal oxidation than the bulk HEAs that have similar compositions in the literature.Such a discrepancy becomes pronounced at higher temperatures.The grain refinement and numerous particle boundaries are responsible for such a distinctive performance of the CSed HEA.     

Developing a product–service system through a productisation strategy: a case from the 3PL industry

A Product–Service System (PSS) is created by combing a tangible product and an intangible service into one integrated offering. Thus, a PSS can be achieved by a production company adding intangible services to a product using a servitisation strategy or by a service company adding a tangible product to a service by means of a productisation strategy. The focus of this paper is on the latter. Our work demonstrates a significant gap in the literature in this area. To address this, we adapt an existing PSS conceptual framework as a means to identify the driving and restraining forces considered by a service company as it explored the possibility of pursuing a PSS productisation strategy. The conceptual framework is applied in an exploratory case study with a 3PL service provider. Application of the framework reveals new driving and restraining forces not previously discussed in the literature. Furthermore, it allows a preliminary quantification of the driving and restraining forces using a force field analysis approach. Our work contributes towards the expansion of the empirical knowledge base in the area of PSS.     

Impact-echo from a unilateral interlayer crack. LCP–BEM modelling and neural identification

The reflection of elastic waves from subsurface interlayer unilateral cracks, with the possibility of crack closing (contact) and frictional effects, is studied by dynamic boundary element method (BEM) combined with a linear complementarity problem (LCP) formulation. The effect of the unilateral crack on the impact–echo response is studied by means of numerical experiments. Further, a neural network model is proposed and tested for the classification of the data based on the numerically generated waveforms. The position or the size of the sublayer crack can be identified from the trained neural network.     

New quality and quantity indices in science (NewQIS): results of the first decade—project progress review

Scientometrics - Strategies employing information science and scientometric approaches were introduced to science policy and management over the past decades. As a rapidly evolving field, new...     

Industrializing metal–organic frameworks: Scalable synthetic means and their transformation into functional materials

For over two decades, metal–organic frameworks (MOFs) have drawn huge attention in the scientific community, with the promise to solve a wide variety of real-world problems. Despite overwhelming interests for this unique class of porous materials, the progress towards actual utilization falls short of the expectation due to the challenging transition from academia to industry. In this review, an up-to-date summary of the progress for MOF industrialization is presented. The latest developments in scalable production of MOFs and MOF processing from their powdered form are discussed to give a broad overview of the route to MOF commercialization. Their industrial utilization potentials are evaluated as well to provide useful insights for the future development in this field. This review aims to serve as an introduction for multidisciplinary research teams who are interested in developing a commercial market for MOF products.     

Comparisons between drum–buffer–rope and material requirements planning: a case study

Drum–Buffer–Rope (DBR) is an alternative approach to manufacturing planning and control that is not as formally tested as Material Requirements Planning (MRP) systems which have traditionally been around for years. Yet, some reports indicate very good performance for DBR and the associated use of synchronous manufacturing principles. But how do these systems compare and relate to one another? Based on our experiences of studying a Bearing Manufacturing Company that actually made the transition from an MRP system to a DBR system, we conduct simulation-based experiments in this paper with the objective of providing a more formal comparison between these two systems than what has been offered in prior literature. To our knowledge, this is the only study of its kind that uses a real-world setting to evaluate key differences and convergence points between comprehensive MRP and DBR systems. Our results show that even though the MRP and DBR systems position inventory differently and provide different dynamic responses to customer demand, there are several operating policies that can be implemented in either system. While the DBR performance in our simulation model was clearly superior to a nominal MRP implementation, we show that even within the constraints of the structural design of MRP system, policy modification based on DBR principles can significantly reduce these performance differences. This finding has an important implication for practising managers who need not necessarily switch from a MRP system to a DBR type of a system (as was done by our case-study firm) in order to take advantage of attractive features of the DBR system. Future researchers can use our study to understand more fully how these Structural Design and Operating Policy differences can be further exploited to implement unique systems that combine the best features of both DBR and MRP systems.     

Theoretical and Experimental Investigations of Identifying the Ingredients of an Oil–Water Mixture Based on a Characteristic Fluid Inverse Problem

To identify the ingredients of an oil–water mixture in petroleum production or petrochemicals process, a method based on a characteristic liquid inverse problem was developed by clarifying its real viscosity and thermal conductivity. A heat transfer and fluid flow model for an oil–water mixture was established for tube flow in this paper. By means of the measured temperature distribution in the tube, the thermal physical properties of the oil–water mixture can be obtained by the governing equations in the model according to their characteristics as a Newtonian or non-Newtonian fluid. The fluid characteristic can be deduced by the rheological properties of the oil–water mixture. Both the Newtonian fluid and non-Newtonian fluid governing equations were established to determine the mixture components. Experiments were also conducted to verify the numerical solutions for the ingredients of the oil–water mixture. The comparison between theoretical solutions and experimental results shows that the maximum error based on the suitable fluid model is 3.11 %, which demonstrated the feasibility of the proposed method for estimating the ingredients of an oil–water mixture.     

Effect of increasing cooling rate from normalising temperature on structure and properties of a Mn–Cr–Mo–V steel

Abstract

The work was undertaken to study the effect of increasing the cooling rate from the normalising temperature on the microstructure and mechanical properties of a Mn–Cr–Mo–V steel. The steel was to a chemical composition suitable for grade 271 in BS 1501 Part 2 and as such would be used in the normalised and tempered condition. Three linear rates of cooling (12, 36, and 120 K min ^?1) from the normalising temperature were used. With the tenfold increase in cooling rate, yield strength increases of about 20% and tensile strength increases of about 15% were obtained in the final tempered steel. Although these strength increases resulted in a loss in ductility and toughness, the values of these properties were still relatively high. The improvements in strength with increases in cooling rate have been related to an increase in the proportion of bainite and a decrease in the amount of ferrite in the resulting microstructure.

MST/683