bluuebunny/crossref_metadata_2025 huggingface dataset:
Increasing accuracy and reliability of ground base settlement calculation
Authors: Korobova Ol’ga , Maksimenko Ljubov , Grigor’ev Dmitrii
Published: April 2019

The article presents the sequence of soil foundations for deformations calculation, taking into account their deformation anisotropy. The calculations were made by the finite element method using the experiment and its mathematical planning. It was found that one can use the numerical experiment results (coefficients tables of soil anisotropy) and calculate soil base sediment and layers of different thickness, using any of the existing methods after determining the index of the soil deformation anisotropy and authenticity, thereby increase their accuracy and reliability.
Cavitation in swirling flows of hydraulic spillways
Authors: Orekhov Genrikh
Published: April 2019

During operation of high-head hydraulic spillway systems, cavitation phenomena often occur, leading to destruction of structural elements of their flow conductor portions. The article is devoted to the study of erosion due to cavitation in the circulation flows of eddy hydraulic spillways, including those equipped with counter-vortex flow energy dissipators. Cavitation destructive effects depend on many factors: intensity consisting in the rate of decrease in the volume or mass of a cavitating body per unit of time, the stage of cavitation, geometric configuration of the streamlined body, the content of air in water, the flow rate, the type of material. The objective of the study consisted in determination of cavitation impacts in circulating (swirling) water flows. The studies were conducted by a method of physical modeling using high-head research installations. Distribution of amplitudes of pulses of shock cavitation impact is obtained according to the frequency of their occurrence depending on the flow velocity, the swirl angle, the height of the cavitating drop wall and the stage of cavitation. The impact energy depending on the stage of cavitation and the flow rate is given for different operating modes of the counter-vortex flow energy dissipators of a hydraulic spillway. In the conclusions, it is noted that cavitation impacts in the circulation flows occur mainly inside the flow, which is a fundamental difference from similar processes in axial flows.
The ontology-based approach to data storage systems technical diagnostics
Authors: Mamoutova Olga V. , Shirokova Svetlana V. , Uspenskij Mikhail B. , Loginova Aleksandra V.
Published: April 2019

Monitoring and diagnosing the state of data storage systems, as well as assessing reliability and troubleshooting, require a formalized health model. A comparative analysis of existing knowledge representation methods has shown that an ontological approach is well suited for this task. This paper introduces a machine-represented data storage reliability ontology with an expert health model as baseline data. Classes of the ontology include the key terms of the reliability domain. Stated requirements for data interpretation tools allow further processing of the ontology-based knowledge base. Described ontology-based diagnostic systems have shown their applicability in the case of data storage systems in the construction industry.
The international clusters in the innovative development of an energy efficient economy
Authors: Skvortsova Inga , Latyshev Roman , Grabovyy Kirill
Published: April 2019

The purpose of this article is to analyze the current level of innovation activity in the Russian Federation, to determine the role of international clusters in the innovative development of the energy efficient country’s economy, while focusing on the formation of the innovative potential of international cooperation of cluster members. The urgency of the creation of cluster associations - international consortia. Examples of the joint implementation of innovative projects in the field of energy-efficient management and the application of new technologies in the field of sustainable energy for megacities are given.
From lean to green management
Authors: Ganebnykh Elena , Fedyaeva Anna , Igoshina Yulia , Ivashchenko Andrey
Published: April 2019

The article is devoted to testing the hypothesis of Melnyk et al. that companies implementing principles of Lean Management System are more environmentally friendly than those that do not implement them. Melnyk tested his hypothesis in North American companies, where Lean Management System and Green Management System are introduced almost simultaneously. Russian production practice is significantly different from the American one, and Lean manufacturing is significantly ahead of Environmental management principles. To test the hypothesis, a formed sample of a number of Russian manufacturing companies was rather small, but the results were fully confirmed.
Distribution of responsibility areas in a construction company
Authors: Minnullin Ruslan , Larkina Alla
Published: April 2019

As of today, a huge number of sales management tools in a construction company are developed. This article proposes the use of a summary matrix of responsibility areas with the distribution of tasks among participants. This matrix is based on the functional fields of each participant in the process. The article presents a practical example of a compiled matrix of distribution of responsibility areas for the Sales Department of the house-building company Snegiri LLC, which was successfully tested. One of the advantages of the proposed toolkit is the possibility of its use for any working group and structural division of a company in any industry.
Construction supervision at the facilities renovation
Authors: Lapidus Azariy , Topchiy Dmitry
Published: April 2019

Article justify the need for a systematic approach to the formation of uniform requirements for the volume and level of construction supervision carried out in the conversion of industrial facilities. Author determines the factors that affect the safety, is the quantitative characteristics of various types of control measures carried out by specialists of state construction supervision both at the facility and in the office. As a hypothesis, author considers the possibility of forming a single deterministic system that provides objective supervision during the conversion and does not create an excessive burden for both the state and the developer. As a result, the existing legislation in the field of state construction supervision is incomplete and partly contradictory. In this article the necessity of formation of scientifically grounded hierarchical organizational and technological system of construction supervision is defined.
The Northern Sea Route in the conditions of the global economic environment of the transport market
Authors: Kuzmin Dmitry , Baginov Andrei , Levin Sergey
Published: April 2019

The paper discusses the prospects for the use of the Northern Sea Route as an option of the transit cargo transportation in international traffic in the conditions of the development of alternative means of communication and the global economic environment of the transport market. The reasons for the low demand for the Northern Sea Route are analyzed. The demand for transportation is predicted.
Methodology for assessing and improving the competitiveness of enterprises in the real sector of the economy
Authors: Pesotskaya Elena , Khakimov Almaz , Alpackaya Irina
Published: April 2019

High rates of the development of market relations and international integration processes imply an increase in the level of competition in leading sectors of the economy, which include energy, construction, industry enterprises and others. The purpose of this paper is to develop a universal methodology for assessing and improving the competitiveness of enterprises in the real sector of the economy. The paper analyzes the structure of cost for quality of products, examines the life cycle of the object in order to determine the approaches to the development and implementation of quality management systems. Using various methods of research, recommendations on the formation and implementation of quality management systems in enterprises of the real sector of the economy were developed in order to increase their competitiveness.
Legal aspect of social entrepreneurship
Authors: Filatova Uliana , Semeryanova Nina , Suslova Svetlana , Gabudina Alena , Kopytova Anna
Published: April 2019

The article discusses the main issues of definition of social entrepreneurship, both from economic and legal point of view. Since Russian legislature is only at the beginning of the way to create legal framework for activities, legislation on social entrepreneurship seems fragmentary and inconsistent. All of that adversely affects development of social entrepreneurship. Official city statistics (Nizhnevartovsk) show that less than a third of all entrepreneurs are interested in this type of activity; entrepreneurs who already have business in the field of social entrepreneurship mostly do not plan to expand current activities in this area. Analysis can contribute to creation of developed socio-economic relations in Russia. It can be achieved by building effective relations between social entrepreneurs and beneficiaries on the one hand, and also between social entrepreneurs and the state on the other.
Research on IFLP optimization model for carbon emission reduction
Authors: GUO Qiannan
Published: April 2019

This study proposed an optimization model combined with Binding Interval Linear Programming (ILP) and Fuzzy linear programming (FLP) Methods and further analyzed from the views of economic output, energy consumption, carbon dioxide emission and emission cost. The optimization model results demonstrated that the heavy energy consumption industries will significantly reduce, and the target of the carbon dioxide emissions per unit of GDP reduction decrease by 40%-45% from 2005 to 2020. In addition, the economic development model will trend to optimize the allocation of resources and green economy. However, a single low-carbon economic policy will always have shortcomings and low efficiency in emission reduction. Hence, the government should combine all emission reduction policies together and establish a lowcarbon economy system that practice production activities need.
Prognostics for an actuator with the combination of support vector regression and particle filter
Authors: Guo Runxia , Sui Jianfei , Chen Jiusheng
Published: April 2019

The accurate prognostics for actuator malfunctions is a challenging task. Developing reliable prognostic methods is vital for providing reasonable preventive maintenance schedules and preventing unexpected failures. Particle filter has been proved to be a traditional approach to deal with actuator prognostic problems. However, the measurement function in the particle filter algorithm cannot be obtained in the prediction process, this paper presents a hybrid framework combining support vector regression (SVR) and particle filter (PF). The SVR output prediction results are employed as the “measurements” for the subsequent PF algorithm. To accomplish the accurate prognostics for actuator fault of civil aircraft, an improved PF based on Kendall correlation coefficient is put forward to solve the problem of particles’ degeneracy. The experimental results are presented, demonstrating that the SVR-PF hybrid approach has satisfactory performance with better prognostics accuracy and higher fault resolution than traditional approaches.
Remaining useful life prognostics for the electro-hydraulic actuator using relevance vector machine and optimized on-line incremental learning
Authors: Dong Jiankang , Wang Jiaqi , Guo Runxia
Published: April 2019

The electro-hydraulic actuator plays a significant role in the automatic flight control system, so it is vital to predict the remaining useful life (RUL) for the electro-hydraulic actuators. Relevance vector machine (RVM) is flourishing in the field of RUL prognostics and gradually applied to the prediction of complex systems or components, but the general RVM cannot achieve on-line prediction efficiently due to its high computational complexity, besides, the sparse RVM model which is only based on historical data set could cause a large prediction error in the long term. To deal with these plights, an optimized incremental learning algorithm based on RVM is presented taking full advantage of the on-line updating samples to improve the precision of prognostics.
Analysis on the endogenous mechanism of big data and tower management framework in intelligent manufacturing enterprises
Authors: Sun Mingwei , Wang Feng , Li Haihua , Liu Ying , Wang Shuli
Published: April 2019

This paper makes an in-depth comparative analysis of years of experience in intelligent manufacturing projects and literature research related to Big Data. The 4.0 value chain model and concept are put forward to carry out the logical analysis of the endogenous relationship drive and endogenous management mechanism of intelligent manufacturing. The intelligent manufacturing business management process under the 4.0 value chain is established, and the tower Big Data management framework of intelligent manufacturing enterprises is innovatively proposed. This paper discusses the connotation, elements and drive relationship of enterprise Big Data from three dimensions of business operation, information drive and management policies. The hierarchical structure and related connotation of Big Data are revealed, and the basic characteristics of intelligent manufacturing enterprises Big Data are analyzed. The purpose of this paper is to clarify the difference of the concept between enterprise Big Data and mass data and open the Big Data fundamental research driven by digitization management. It provides basic innovative ideas and scientific research methods for the new generation of digital virtual simulation, digital factory construction and industrial chain management.
Early and late rice identification from Tiangong- 2 wide band images based on CNN
Authors: Zhou Zhuang , Li Shengyang , Shao Yuyang
Published: April 2019

The wide band images acquired from the Tiangong-2 space laboratory covers many spectral bands such as visible light, shortwave infrared and thermal infrared. These high-quality images can be used for space science experiments such as earth observation. In this paper, we use CNN (convolutional neural networks) to extract the spectral features of different landcover from the wide band images, then identify the early rice and the late rice accurately in Huarong County, Hunan Province, China. With advanced techniques such as deep learning, the spatial distribution information of crops can be effectively obtained from the wide band images which can provide data services for agricultural production management.
Analysis of shrinkage and creep effect for bridge widening based on TB-FEM method and experimental research
Authors: Peng Keke , Wen Fangzhen
Published: April 2019

Based on TB-FEM method and laboratory test, the influence of shrinkage and creep on the structure of widened bridge is studied. The shrinkage test uses C50 concrete and C50 double-mixture (steel polyester fiber) concrete to prepare the standard prism specimen, and the creep test uses the 15m hollow slab which exactly has the same material, size, prestress and construction method of a real bridge as the creep test specimen. The strain-time curve obtained by shrinkage and creep is used to define the shrinkage and creep characteristics of the material, and Trost-Bazant is combined with finite element method to analyze the mechanical response of the new and old bridge splicing structure caused by shrinkage and creep. The result shows that under the condition of rigid splicing, the new bridge should be supported by the simply supported structure, and it is not suitable to use the same simply supported and continuous hollow slab as the original bridge. Theoretical analysis and example study show that combination of laboratory test and TB-FEM method can reasonably analyze the effect of shrinkage and creep on bridge widening, and provide a theoretical basis for the type selection of widening structure.
A novel method for SIFT features matching based on feature dimension matching degree
Authors: Yang Yao , Wei Jinkang , Zhan Ximing , Miao Xikui
Published: April 2019

We proposes a method for fast matching SIFT feature points based on SIFT feature descriptor vector element matching. First, we discretize each dimensional feature element into an array address based on a fixed threshold value and store the corresponding feature point labels in an address. If the same dimensional feature element of the descriptor vector has the same discrete value, their feature point labels may fall into the same address. Secondly, we search the mapping address of the feature descriptor vector element to obtain the matching state of the corresponding dimensions of the feature descriptor vector, thus obtaining the number of dimensions matching between feature points and feature dimension matching degree. Then we use the feature dimension matching degree to obtain the suspect matching feature points. Finally we use the Euclidean distance to eliminate the mismatching feature points to obtain accurate matching feature point pairs. The method is essentially a high-dimensional feature vector matching method based on local feature vector element matching. Experimental results show that the new algorithm can guarantee the number of matching SIFT feature points and their matching accuracy and that its running time is similar to that of HKMT, RKDT and LSH algorithms
Detect-and-describe: Joint learning framework for detection and description of objects
Authors: Zafar Adeel , Khalid Umar
Published: April 2019

Traditional object detection answers two questions; “what” (what the object is?) and “where” (where the object is?). “what” part of the object detection can be fine grained further i-e. “what type”, “what shape” and “what material” etc. This results in shifting of object detection task to object description paradigm. Describing object provides additional detail that enables us to understand the characteristics and attributes of the object (“plastic boat” not just boat, “glass bottle” not just bottle). This additional information can implicitly be used to gain insight about unseen objects (e.g. unknown object is “metallic”, “has wheels”), which is not possible in traditional object detection. In this paper, we present a new approach to simultaneously detect objects and infer their attributes, we call it Detectand- Describe (DaD) framework. DaD is a deep learning-based approach that extends object detection to object attribute prediction as well. We train our model on aPascal train set and evaluate our approach on aPascal test set. We achieve 97.0% in Area Under the Receiver Operating Characteristic Curve (AUC) for object attributes prediction on aPascal test set. We also show qualitative results for object attribute prediction on unseen objects, which demonstrate the effectiveness of our approach for describing unknown objects.
Handwritten capital letter recognition based on OpenCV
Authors: Lu Yuncong
Published: April 2019

Handwriting capitalization recognition is a function of distinguishing handwritten capital letters by means of machine or computer intelligence, which is classified into the field of optical character recognition. Given that capital letters are widely used around the world, identification and analysis are often used as the main components of some control systems. Therefore, the research on handwritten capital letter recognition is also very practical and has important practical significance. The key part of the research contained in this paper is the image preprocessing and the optimal selection of feature vectors, and finally completes the design of handwritten digit recognition system. In this paper, the Fourier and Bayesian commonly used are compared, and eventually the Fourier transform feature is applied to the system classification identification. After completing the test on the relevant experimental data, the results show that the handwritten capital recognition system established in this paper has a high recognition accuracy for handwritten capital letters after repeated training.
Virtual ground truth, and pre-selection of 3D interest points for improved repeatability evaluation of 2D detectors
Authors: Lang Simon R , Luerssen Martin H , Powers David M
Published: April 2019

In Computer Vision, finding simple features is performed using classifiers called interest point (IP) detectors, which are often utilised to track features as the scene changes. For 2D based classifiers it has been intuitive to measure repeated point reliability using 2D metrics given the difficulty to establish ground truth beyond 2D. The aim is to bridge the gap between 2D classifiers and 3D environments, and improve performance analysis of 2D IP classification on 3D objects. This paper builds on existing work with 3D scanned and artificial models to test conventional 2D feature detectors with the assistance of virtualised 3D scenes. Virtual space depth is leveraged in tests to perform pre-selection of closest repeatable points in both 2D and 3D contexts before repeatability is measured. This more reliable ground truth is used to analyse testing configurations with a singular and 12 model dataset across affine transforms in x, y and z rotation, as well as x, y scaling with 9 well known IP detectors. The virtual scene's ground truth demonstrates that 3D preselection eliminates a large portion of false positives that are normally considered repeated in 2D configurations. The results indicate that 3D virtual environments can provide assistance in comparing the performance of conventional detectors when extending their applications to 3D environments, and can result in better classification of features when testing prospective classifiers' performance. A ROC based informedness measure also highlights tradeoffs in 2D/3D performance compared to conventional repeatability measures.
Comparison of harmonic limits and evaluation of the international standards
Authors: WANG Zijiang , LI Qionglin , TANG Yuzheng , LIU Shuming , DAI Shuangyin
Published: April 2019

The paper takes the Chinese standard GB/T 14549-1993, the British Engineering Recommendation G5/4-1, the Institute of Electrical and Electronics Engineers IEEE Std 519-2014 and the part of IEC 61000-3 series standard as an example. Then summarize the difference of harmonic limits, the different processing methods of harmonic impedance, and the different summation law of each standard. Compare the harmonic limit calculation and evaluation methods of Chinese GB/T 14549-1993, British G5/4-1 and IEEE Std 519-2014 standard in detail, summarize the characteristics of the three standards in disturbance emission evaluation and introduce examples to verify the conclusion. Finally, summarize the characteristics and differences of mentioned harmonic standards.
The optimal population size under pollution and migration externalities: a spatial control approach
Authors: La Torre Davide , Liuzzi Danilo , Marsiglio Simone
Published: April 2019

We analyze the implications of pollution and migration externalities on the optimal population dynamics in a spatial setting. We focus on a framework in which pollution affects the mortality rate and decreases utility, while migration occurs within the spatial economy. Agents optimally determine their fertility rate which, along with pollution-induced mortality and spatial migration, determines the net population growth rate. This setting implies that human population follows an endogenous logistic-type dynamics where fertility choices determine what the optimal limit of human population will be. We compare the decentralized and the centralized outcomes showing that such fertility decisions generally differ, quantifying the extent to which pollution and migration induced externalities matter in determining the difference between the two outcomes. We show that, due to the effects of pollution on utility and mortality, both the optimal fertility rate and the population size are smallest in the centralized economy but migration effects change not only the size of these differences but also their direction, suggesting that the spatial channel is an important mechanism to account for in the process of policymaking.
The existence and asymptotic stability of periodic solutions with an interior layer of Burgers type equations with modular advection
Authors: Nefedov Nikolay
Published: April 2019

We consider a new class of singularly perturbed parabolic periodic boundary value problems for reaction-advection-diffusion equations: Burgers type equations with modular advection. We construct the interior layer type formal asymptotics and propose a modified procedure to get asymptotic lower and upper solutions. By using sufficiently precise lower and upper solutions, we prove the existence of a periodic solution with an interior layer and estimate the accuracy of its asymptotics. The asymptotic stability of this solution is also established.
Multiscale dynamics of an adaptive catalytic network
Authors: Kuehn Christian
Published: April 2019

We study the multiscale structure of the Jain–Krishna adaptive network model. This model describes the co-evolution of a set of continuous-time autocatalytic ordinary differential equations and its underlying discrete-time graph structure. The graph dynamics is governed by deletion of vertices with asymptotically weak concentrations of prevalence and then re-insertion of vertices with new random connections. In this work, we prove several results about convergence of the continuous-time dynamics to equilibrium points. Furthermore, we motivate via formal asymptotic calculations several conjectures regarding the discrete-time graph updates. In summary, our results clearly show that there are several time scales in the problem depending upon system parameters, and that analysis can be carried out in certain singular limits. This shows that for the Jain–Krishna model, and potentially many other adaptive network models, a mixture of deterministic and/or stochastic multiscale methods is a good approach to work towards a rigorous mathematical analysis.
Effect of maturity stage on the chemical composition of argan fruit pulp
Authors: Harhar Hicham , Gharby Said , El Idrissi Yousra , Pioch Daniel , Matthäus Bertrand , Charrouf Zoubida , Tabyaoui Mohamed
Published: April 2019

Argan tree, a species endemic to Southern Morroco, is well known for its kernel oil used in cosmetics and health-food, but the corresponding pulp attracted less interest from researchers and little is known about its chemical composition and evolution during maturation. The pulp of argan fruits monthly harvested during the ripening period based on fruit color (April to July), was analyzed. With progressing ripeness various changes were observed in the chemical composition, such as (i) a four-fold increase of total soluble sugars content (glucose, fructose and saccharose), and of Fe (75–165 ppm), but also (ii) a drop of many components, such as proteins (10.1–6.4%), and cell wall polymers, lignin (14.9–5.9%) and hemicellulose and cellulose. Hexane-soluble compounds found in substantial amount (10.7% in April) also decreased with time: the pulp oil peak (8.3%) was in April and June, and that of polyisoprene in June (3.6%). Therefore the stage of maturity (harvest date) is to be considered, without affecting the quality of the argan oil.
Cemracs 2017: numerical probabilistic approach to MFG
Authors: Angiuli Andrea , Graves Christy V. , Li Houzhi , Chassagneux Jean-François , Delarue François , Carmona René
Published: April 2019

This project investigates numerical methods for solving fully coupled forward-backward stochastic differential equations (FBSDEs) of McKean-Vlasov type. Having numerical solvers for such mean field FBSDEs is of interest because of the potential application of these equations to optimization problems over a large population, say for instance mean field games (MFG) and optimal mean field control problems. Theory for this kind of problems has met with great success since the early works on mean field games by Lasry and Lions, see [29], and by Huang, Caines, and Malhamé, see [26]. Generally speaking, the purpose is to understand the continuum limit of optimizers or of equilibria (say in Nash sense) as the number of underlying players tends to infinity. When approached from the probabilistic viewpoint, solutions to these control problems (or games) can be described by coupled mean field FBSDEs, meaning that the coefficients depend upon the own marginal laws of the solution. In this note, we detail two methods for solving such FBSDEs which we implement and apply to five benchmark problems. The first method uses a tree structure to represent the pathwise laws of the solution, whereas the second method uses a grid discretization to represent the time marginal laws of the solutions. Both are based on a Picard scheme; importantly, we combine each of them with a generic continuation method that permits to extend the time horizon (or equivalently the coupling strength between the two equations) for which the Picard iteration converges.
Stochastic approximation schemes for economic capital and risk margin computations
Authors: Barrera David , Crépey Stéphane , Diallo Babacar , Fort Gersende , Gobet Emmanuel , Stazhynski Uladzislau
Published: April 2019

We consider the problem of the numerical computation of its economic capital by an insurance or a bank, in the form of a value-at-risk or expected shortfall of its loss over a given time horizon. This loss includes the appreciation of the mark-to-model of the liabilities of the firm, which we account for by nested Monte Carlo à la Gordy and Juneja [17] or by regression à la Broadie, Du, and Moallemi [10]. Using a stochastic approximation point of view on value-at-risk and expected shortfall, we establish the convergence of the resulting economic capital simulation schemes, under mild assumptions that only bear on the theoretical limiting problem at hand, as opposed to assumptions on the approximating problems in [17] and [10]. Our economic capital estimates can then be made conditional in a Markov framework and integrated in an outer Monte Carlo simulation to yield the risk margin of the firm, corresponding to a market value margin (MVM) in insurance or to a capital valuation adjustment (KVA) in banking parlance. This is illustrated numerically by a KVA case study implemented on GPUs.
Some non monotone schemes for Hamilton-Jacobi-Bellman equations
Authors: Warin Xavier
Published: April 2019

We extend the theory of Barles Jakobsen [3] for a class of almost monotone schemes to solve stationary Hamilton Jacobi Bellman equations. We show that the monotonicity of the schemes can be relaxed still leading to the convergence to the viscosity solution of the equation even if the discrete problem can only be solved with some error. We give some examples of such numerical schemes and show that the bounds obtained by the framework developed are not tight. At last we test the schemes.
Inter-comparison of parameters and exposure scenarios in risk-assessment methodologies for radiological and chemical soil contamination
Authors: Radulovic S. , Pepin S.
Published: April 2019

Various guidelines and models exist to assess the dose resulting from a radiological soil contamination. Analogous methodologies have been published to assess the chemical risk from non-radioactive pollutants present in soil. Although most of these methodologies insist on the need to use as much as possible site-specific parameters in the assessment-process, they also suggest a set of default or example parameters. In this study, we compare the suggested parameter values of four different national guidelines for risk-assessment of contaminated soil from France, Germany, Britain and Belgium. The Belgian methodology had been developed for the assessment of chemical risk while the three others are specifically dedicated to radiological risk. Significant discrepancies are found between the parameters of different national guidelines, which stresses the need for carefulness and sound expert judgment in the choice of the parameters of a risk-assessment process.
Enantioselective Arylation of 3-Carboxamide Oxindoles with Quinone Monoimines and Synthesis of Chiral Spirooxindole-benzofuranones
Authors: Chen Hui , Liu Hui , Zhao Si-Han , Cheng Shao-Bing , Xu Xiao-Ying , Yuan Wei-Cheng , Zhang Xiao-Mei
Published: April 2019

A highly enantioselective arylation of 3-carboxamide oxoindoles with quinone monoimines is described. Various 3-aryl-3-carboxamide oxindoles with an all-carbon quaternary center were obtained in moderate to good yields (up to 99%) with moderate to good enantioselectivities (up to 98%) in the presence of a bifunctional thiourea-tertiary amine catalyst. The absolute configuration of one product was determined by an X-ray crystal structural analysis and the absolute configurations of the other products can be assigned by analogy. Moreover, several chiral spirooxindole-benzofuranones were synthesized from the 3-aryl-3-carboxamide oxindoles in moderate yields with moderate to good enantioselectivities.
Peptide Modifications: Versatile Tools in Peptide and Natural Product Syntheses
Authors: Servatius Phil , Junk Lukas , Kazmaier Uli
Published: April 2019

Peptide modifications via C–C bond formation have emerged as valuable tools for the preparation and alteration of non-proteinogenic amino acids and the corresponding peptides. Modification of glycine subunits in peptides allows for the incorporation of unusual side chains, often in a highly stereoselective manner, orchestrated by the chiral peptide backbone. Moreover, modifications of peptides are not limited to the peptidic backbone. Many side-chain modifications, not only by variation of existing functional groups, but also by C–H functionalization, have been developed over the past decade. This account highlights the synthetic contributions made by our group and others to the field of peptide modifications and their application in natural product syntheses.

1 Introduction

2 Peptide Backbone Modifications via Peptide Enolates

2.1 Chelate Enolate Claisen Rearrangements

2.2 Allylic Alkylations

2.3 Miscellaneous Modifications

3 Side-Chain Modifications

3.1 C–H Activation

3.1.1 Functionalization via Csp3–H Bond Activation

3.2.2 Functionalization via Csp2–H Bond Activation

3.2 On Peptide Tryptophan Syntheses

4 Conclusion
Monocyte Chemoattractant Protein (MCP)-1 in Rotavirus-Associated White Matter Injury in Newborns
Authors: Yeom Jung Sook , Jo Jae-Young , Park Ji Sook , Kim Young-Soo , Chung Ju-Young , Han Tae-Hee , Seo Ji-Hyun , Park Eun Sil , Lim Jae-Young , Woo Hyang-Ok , Youn Hee-Shang , Park Chan-Hoo
Published: April 2019

Recent reports have suggested an association between rotavirus infection and a distinctive pattern of white matter injury (WMI) in neonates with seizures; however, the connection between the two is not fully understood. To evaluate the underlying mechanism, we profiled and compared eight cytokines (IL [interleukin]-1β, IL-6, IL-8, IL-10, IFN-γ [interferon-γ ], MCP-1 [monocyte chemoattractant protein-1], MIP-1β [macrophage inflammatory protein-1β], and TNF-α [tumor necrosis factor-α]) in the cerebrospinal fluid (CSF) of 33 neonates with seizures who had no other well-known causes of seizures and 13 control patients (rotavirus-induced gastroenteritis but without seizures). Among the 33 neonates with seizures, 9 showed WMI and all were infected with rotavirus (R + W + ). Among the 24 patients without WMI, 11 were infected with rotavirus (R + W − ) and 13 were not (R − W − ).Only MCP-1 and MIP-1β were different between the groups. MCP-1 was increased in R+ W+ compared with R + W− (p < 0.01), R − W− (p < 0.01), and control (p = 0.03) patients. MIP-1β was decreased in R + W+ compared with R − W− (p < 0.01) and control (p < 0.01), but not R + W− (p = 0.23) patients. MCP-1 and MIP-1β are C-C chemokines that recruit immune cells to the site of inflammation. Our pilot study suggests MCP-1-mediated monocyte recruitment may be linked with this complication caused by rotavirus.
What guns mean: the symbolic lives of firearms
Authors: Metzl Jonathan M.
Published: April 2019

This article presents an overview of the symbolic tensions underlying representations of firearms and gun-related violence. The essay frames central questions that deserve further interrogation: what larger social and political contexts surround guns? How do narrations of gun rights or gun trauma map onto larger scripts about matters such as identity, bias, racism, or nationalism? What meanings do guns accrue for people and communities when these guns are not shooting bullets or causing mortal wounds? The paper lays out disciplinary terrain required to address these questions, calling on expertize from the social sciences, humanities, and arts.
Ignition thresholds of aluminized HMX-based polymer-bonded explosives
Authors: Miller Christopher , Kim Seokpum , Horie Yasuyuki , Zhou Min
Published: April 2019

The ignition of aluminized HMX-based polymer-bonded explosives (PBXs) under shock loading is studied via mesoscale simulations. The conditions analyzed concern loading pulses of 20 nanoseconds to 0.8 microseconds in duration and impact piston velocities on the order of 400-1000 m/s or loading stresses on the order of 3-14 GPa. The sets of samples studied have stochastically similar microstructures consisting of a bimodal distribution of HMX grains, an Estane binder, and aluminum particles 50-100 µm in diameter. The computational model accounts for constituent elasto-viscoplasticity, viscoelasticity, bulk compressibility, fracture, interfacial debonding, internal contact, bulk and frictional heating, and heat conduction. The analysis focuses on the development of hotspots under different material settings and loading conditions. In particular, the ignition thresholds in the forms of the James relation and the Walker-Wasley relation and the corresponding ignition probability are calculated and expressed as functions of the aluminum volume fraction for the PBXs analyzed. It is found that the addition of aluminum raises the ignition thresholds, causing the materials to be less sensitive. Dissipation and heating mechanism changes responsible for this trend are delineated.
Ultrafast Rayleigh-like streaming in a sub-wavelength slit between two phononic crystal plates
Authors: Li Fei , Xia Xiangxiang , Deng Zhiting , Lei Junjun , Shen Yaxi , Lin Qin , Zhou Wei , Meng Long , Wu Junru , Cai Feiyan , Zheng Hairong
Published: April 2019

We demonstrate a type of boundary-driven streaming in a subwavelength slit (the slit width is smaller than the acoustic wavelength) between two phononic crystal plates (PCPs) by using the limiting velocity method. It is found that this streaming has the characteristics of four-quadrant streaming similar to classical Rayleigh streaming, and the smaller the slit width, the larger is the maximum velocity of streaming. The maximum velocity of the demonstrated streaming is approximately four orders of magnitude higher than that of classical Rayleigh streaming in two rigid plates with the same slit width of 15 μm. In addition, in the case of this streaming, the vortex sizes are related to the lattice constant of the PCPs, which can be much smaller than those realized in Rayleigh streaming. These effects originate from the strong antiphase coupling of the nonleaky zero-order antisymmetric A0 Lamb modes intrinsic to these thin plates. We denote this streaming as ultrafast Rayleigh-like streaming, which can find potential application in acoustofluidic devices for particle manipulation, rapid mixing and chemical reactions, etc.
Characteristics and performances of a small-scale model of the closed-circuit multiple controlled fan wind tunnel
Authors: Li Xianying , Yao Yu , Zhao Biao , Wu Hongtao , Chen Bin , Yi Tao
Published: April 2019

The development of a method to simulate desired approach turbulence characteristics and improve the typhoon resistance ability for complex building and transmission tower-line system in a multiple controlled fan wind tunnel is described. A case study is investigated using a closed-circuit single controlled fan wind tunnel model of the Full-Scale Test Facility at the State Grid Fujian Electric Power Research Institute for State Grid Wind Tunnel Laboratory. A small-scale model of the closed-circuit single controlled fan wind tunnel is designed and established to simulate the turbulence characteristics and develop the target turbulent flow generating methods efficiently. The results reveal that the value of the maximum average wind speed can reach 18.2 m/s and the maximum circular frequency is 7 Hz. Here, the mean wind speed of the sinusoidal wave flow is 15.1 m/s at the peak of amplitude of 3.8 m/s. The generated sinusoidal wave flow has a high correlation coefficient at 94.3% with the target.
Manganese ion implanted ultrananocrystalline diamond films: Optical and electrical characterization
Authors: Kunuku Srinivasu , Chen Chien-Hsu , Hsieh Ping-Yen , Lin Bo-Rong , Tai Nyan-Hwa , Niu Huan
Published: April 2019

We report the optical and electrical properties of high-dose (1015–1017 ions/cm2) Mn-ion implanted ultrananocrystalline diamond (Mn-UNCD) films. Mn-ion implantation and post-annealing of UNCD films lead to the formation of Mn-related color centers, characterized in Mn-UNCD films by their zero phonon line emissions at 621.2 nm and phonon sidebands at 611.2 nm and 630.3 nm. Raman spectra of Mn-UNCD films indicated amorphization via high-dose Mn-ion implantation and that the annealing process results in graphitization of the films. The Mn-UNCD film implanted with the Mn-ion dose of 1017 ions/cm2 exhibits a conductivity of 122.25 (Ω cm)−1, as well as enhanced field electron emission (FEE) properties such as a turn-on field of 10.67 V/μm and a FEE current density of 0.85 mA/cm2.
Cage occupancies, lattice constants, and guest chemical potentials for structure II hydrogen clathrate hydrate from Gibbs ensemble Monte Carlo simulations
Authors: Brumby Paul E. , Yuhara Daisuke , Hasegawa Tomohiro , Wu David T. , Sum Amadeu K. , Yasuoka Kenji
Published: April 2019

In this paper, equilibrium properties of structure II hydrates of hydrogen were determined from Monte Carlo simulations in the isothermal-isobaric Gibbs ensemble. Water and hydrogen molecules are described by the TIP4P/Ice and Silvera-Goldman models, respectively. The use of the Gibbs ensemble has many key advantages for the simulation of hydrates. By the separation of hydrogen vapor and hydrate phases into their own domains, coupled with transfer moves of hydrogen molecules between domains, cage occupancies were determined. Furthermore, the choice of this ensemble also allows equilibrium lattice constants and guest molecule chemical potentials to be straightforwardly estimated. Results for hydrogen mass fractions indicate reasonable agreement with prior simulation data and theoretical models, while detailed analysis of cage occupancy distributions and neighboring cage pair occupancy combinations gives valuable insight into the behavior of this hydrate at the inter-cage scale. These results will aid in the construction of theoretical models, for which knowledge of the occupancy of neighboring cages is of great importance. In support of previous experimental and theoretical works, we also find evidence of double occupancy of a few small cages inside of the hydrate stability zone, albeit at very high pressures; approximately 0.1% of small cages are doubly occupied at 300 MPa, for temperatures of 225 K and 250 K.
Propagating modes of the travelling wave in a microwave plasma torch with metallic enclosure
Authors: Zhang Wencong , Wu Li , Huang Kama , Tao Junwu
Published: April 2019

For the discharges sustained by the travelling electromagnetic waves, the wave propagation characteristics are of great importance to discharge maintenance and stability. This study aims to investigate the propagating electromagnetic modes of the travelling wave in a cylindrical discharge tube bound by a metallic enclosure based on a microwave plasma torch. In certain particular circumstances, it is found that the cylindrical discharge tube with metallic enclosure is able to change from a one-conductor circular waveguide to a two-conductor-like coaxial waveguide. Such a change allows the travelling wave to propagate in the transverse electromagnetic mode, which has rarely been noticed before. Regarding this transition, a new criterion is proposed to determine the formation of the two-conductor-like waveguide structure. Existence conditions of different propagating modes of the travelling wave are further discussed with respect to different glass tube wall thicknesses and dielectric properties. The results indicate that it is possible to control the propagating modes of the travelling wave for different purposes by choosing a proper glass tube.
A comparison of pre-impact gas cushioning and Wagner theory for liquid-solid impacts
Authors: Ross Snizhana , Hicks Peter D.
Published: April 2019

The normal impact of a symmetric rigid body with an initially quiescent liquid half-space is considered using both Wagner theory and a model of viscous gas pre-impact cushioning. The predictions of these two theories are compared for a range of different body shapes. Both theories assume that the impactor has small deadrise angle. Novel solutions of the Wagner normal impact problem for a symmetric body with a power-law shape are presented, which generalize the well-known results for a parabola and a wedge. For gas cushioned pre-impacts, it is shown that a pocket of gas is entrained even for body shapes with a cusp at the body minimum. A scaling law is developed that relates the dimensions of the trapped gas pocket to the slope of the body. For pre-impact gas cushioning, surface tension is shown to smooth the liquid free-surface and delay the instant of touchdown for a smooth parabolic body, while for a wedge, increasing surface tension initially delays touchdown, before hastening touchdown as the importance of surface tension is increased further. For a flat-bottomed wedge, gas entrainment is again predicted in the gas-cushioning model although the location of initial touchdown, either on the transition between the wedge and the flat bottom or along the side of the wedge, now depends upon the parameters of the body shape.
Influence of electric field on deformation of a drop in shear flow
Authors: Nath Binita , Biswas Gautam , Dalal Amaresh
Published: April 2019

The dynamics of a droplet in shear flow under the influence of an external electric field are investigated by performing extensive numerical simulations. The study is carried out by solving two-dimensional electrohydrodynamic equations, and the interface is captured using a volume-of-fluid approach. It is observed that with an increase in the drop size, a confined drop exhibits enhanced deformation and preferred orientation with the flow direction. For the case of dielectric fluids, the deformation of the drops can be either enhanced or reduced by varying the permittivity ratio and electric field strength. The nature of the polarisation forces acting at the interface can be either compressive or tensile depending on the magnitude of the permittivity ratio. The local electric field intensity inside the drop is significantly altered due to the permittivity contrast between the fluids. The computations for leaky dielectric fluids reveal that the deformation of the drop can be effectively tuned by altering the permittivity as well as the conductivity ratios. The nature of charge accumulation and the electric forces acting at the interface are critically dependent on the relative contrast between the electric properties of both the phases. The conductivity ratio decides the magnitude and nature of charge at the upper and lower portions of the droplet interface, thereby fundamentally maneuvering the droplet dynamics under the applied electric field.