bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of Disulfide‐Bridged N‐Phenyl‐N′‐(alkyl/aryl/heteroaryl)urea Derivatives and Evaluation of Their Antimicrobial Activities
Authors: Dilem Doğan Şengül , Buran Sümeyye , Gözde Gündüz Miyase , Özkul Ceren , Siva Krishna Vagolu , Sriram Dharmarajan 
Published: September 2019

AbstractThe discovery of new antimicrobial agents is extremely needed to overcome multidrug‐resistant bacterial and tuberculosis infections. In the present study, eight novel substituted urea derivatives (10a–10h) containing disulfide bond were designed, synthesized and screened for their in vitro antimicrobial activities on standard strains of Gram‐positive and Gram‐negative bacteria as well as on Mycobacterium tuberculosis. According to the obtained results, antibacterial effects of the compounds were found to be considerably better than their antimycobacterial activities along with their weak cytotoxic effects. Molecular docking studies were performed to gain insights into the antibacterial activity mechanism of the synthesized compounds. The interactions and the orientation of compound 10a (1,1′‐((disulfanediylbis(methylene))bis(2,1‐phenylene))bis(3‐phenylurea)) were found to be highly similar to the original ligand within the binding pocket E. faecalis β‐ketoacyl acyl carrier protein synthase III (FabH). Finally, a theoretical study was established to predict the physicochemical properties of the compounds.
Lewis Acid and Base Catalysis of YNbO4 Toward Aqueous‐Phase Conversion of Hexose and Triose Sugars to Lactic Acid in Water
Authors: Kim Minjune , Ronchetti Silvia , Onida Barbara , Ichikuni Nobuyuki , Fukuoka Atsushi , Kato Hideki , Nakajima Kiyotaka 
Published: September 2019

AbstractAmphoteric YNbO4 was synthesized by the simple coprecipitation using (NH4)3[Nb(O2)4] and Y(NO3)3, and examined as a new solid acid‐base bifunctional catalyst for various reactions including aqueous‐phase conversion of glucose to lactic acid. After drying the white precipitate at 353 K for 3 h, the resultant oxide is an amorphous YNbO4 with high densities of Lewis acid sites (0.18 mmol g−1) and base sites (0.38 mmol g−1). Negatively‐charged lattice oxygen of amorphous YNbO4 functioned as Lewis base sites that promote a Claisen‐Schmidt‐type condensation reaction with acetylacetone and benzaldehyde with comparable activity to reference catalysts. Amorphous YNbO4 can also be applicable to the production of lactic acid from glucose in water, which gives relatively high yields (19.6 %) compared with other reference catalysts. Mechanistic studies using glucose‐1‐d and 2H nuclear magnetic resonance spectroscopy (NMR) revealed that YNbO4 first converts glucose to two carbohydrates (glyceraldehyde and pyruvaldehyde) through dehydration via the formation of 3‐deoxyglucosone and subsequent retro‐aldolization, and these intermediates are then converted to lactic acid by both dehydration and isomerization through hydride transfer.
Elucidation of the Mechanism of Silver‐Catalyzed Inverse Electron‐Demand Diels‐Alder (IEDDA) Reaction of 1,2‐Diazines and Siloxy Alkynes
Authors: Avcı Öyküm Naz , Catak Saron , Dereli Büşra , Aviyente Viktorya , Dedeoglu Burcu 
Published: September 2019

AbstractDensity functional theory (DFT) calculations were utilized to reveal the effect of highly efficient transition metal catalysis in inverse electron demand Diels‐Alder (IEDDA) reactions. The silver‐catalyzed IEDDA reactions of 1,2‐diazines and siloxy alkynes were investigated to highlight the effect of the catalyst and its mode of action. Two different reaction pathways, concerted and stepwise, were explored as well as the uncatalyzed reaction. Computations elucidate the details of the highly efficient Ag catalyst in IEDDA reaction, and are consistent with previous experimental studies. The mode of action for the catalyst is fully revealed and its specific effect on the regioselectivity/specificity of the reaction is established.
The Key Role of Water Activity for the Operating Behavior and Dynamics of Oxygen Depolarized Cathodes
Authors: Röhe Maximilian , Botz Alexander , Franzen David , Kubannek Fabian , Ellendorff Barbara , Öhl Denis , Schuhmann Wolfgang , Turek Thomas , Krewer Ulrike 
Published: September 2019

AbstractAdvanced chlor‐alkali electrolysis with oxygen depolarized cathodes (ODC) requires 30 % less electrical energy than conventional hydrogen‐evolution‐based technology. Herein, we confirm that the activities of hydroxide and water govern the ODC performance and its dynamics. Experimental characterization of ODC under varying mass transfer conditions on the liquid side reveals large differences in the polarization curves as well as in potential step responses of the electrodes. Under convective transport in the liquid electrolyte, the ODC is not limited by mass transfer in its current density atj>3.9 kA m−2, whereas transport limitations are already reached atj≈1.3 kA m−2with a stagnant electrolyte. Since gas phase conditions do not differ significantly between the measurements, these results are in contrast the common assumption that oxygen supply determines ODC performance. A dynamic model reveals the strong influence of the electrolyte mass transfer conditions on oxygen availability and thus performance. Dynamic responses of the current density to step‐wise potential changes are dominated by the mass transport of water and hydroxide ions, which is by orders of magnitude faster with convective electrolyte flow. Without convective liquid electrolyte transport, a high accumulation of hydroxide ions significantly lowers the oxygen solubility. Thus, a fast mass transport of water and hydroxide is essential for high ODC performance and needs to be ensured for technical applications. The predicted accumulation of ions is furthermore validated experimentally by means of scanning electrochemical microscopy. We also show how the outlined processes can explain the distinctively different potential step responses with and without electrolyte convection.
Molecular Electrocatalysts for the Hydrogen Evolution Reaction: Input from Quantum Chemistry
Authors: Barrozo Alexandre , Orio Maylis 
Published: September 2019

AbstractIn the pursuit of carbon‐free fuels, hydrogen can be considered as an apt energy carrier. The design of molecular electrocatalysts for hydrogen production is important for the development of renewable energy sources that are abundant, inexpensive, and environmentally benign. Over the last 20 years, a large number of electrocatalysts have been developed, and considerable efforts have been directed toward the design of earth‐abundant, first‐row transition‐metal complexes capable of promoting electrocatalytic hydrogen evolution reaction (HER). In this context, numerical approaches have emerged as powerful tools to study the catalytic performances of these complexes. This review covers some of the most significant theoretical mechanistic studies of biomimetic and bioinspired homogeneous HER catalysts. The approaches employed to study the free energy landscapes are discussed and methods used to obtain accurate estimates of relevant observables required to study the HER are presented. Furthermore, the structural and electronic parameters that govern the reactivity, and are necessary to achieve efficient hydrogen production, are discussed in view of future research directions.
Population genetic analysis of the domestic Bactrian camel in China by RAD‐seq
Authors: Liu Chenmiao , Chen Huiling , Ren Zhanjun , Zhang Chengdong , Yang Xuejiao 
Published: September 2019

AbstractRestriction site‐associated DNA sequencing (RAD‐seq) is one of the most effective high‐throughput sequencing technologies for SNP development and utilization and has been applied to studying the origin and evolution of various species. The domestic Bactrian camels play an important role in economic trade and cultural construction. They are precious species resources and indispensable animals in China's agricultural production. Recently, the rapid development of modern transportation and agriculture, and the deterioration of the environment have led to a sharp decline in the number of camels. Although there have been some reports on the evolution history of the domestic Bactrian camel in China, the origin, evolutionary relationship, and genetic diversity of the camels are unclear due to the limitations of sample size and sequencing technology. Therefore, 47 samples of seven domestic Bactrian camel species from four regions (Inner Mongolia, Gansu, Qinghai, and Xinjiang) were prepared for RAD‐seq analysis to study the evolutionary relationship and genetic diversity. In addition, seven domestic Bactrian camel species are located in different ecological zones, forming different characteristics and having potential development value. A total of 6,487,849 SNPs were genotyped. On the one hand, the filtered SNP information was used to conduct polymorphism mapping construction, LD attenuation analysis, and nucleotide diversity analysis. The results showed that the number of SNPs in Dongjiang camel was the highest, the LD coefficient decayed the fastest, and the nucleotide diversity was the highest. It indicates that Dongjiang camel has the highest genetic diversity. On the other hand, the filtered SNPs information was used to construct the phylogenetic tree, and FST analysis, inbreeding coefficient analysis, principal component analysis, and population structure analysis were carried out. The results showed that Nanjiang camel and Beijiang camels grouped together, and the other five Bactrian camel populations gathered into another branch. It may be because the mountains in the northern part of Xinjiang and the desert in the middle isolate the two groups from the other five groups.
Divergent color signals from homologous unfeathered ornaments in two congeneric grouse
Authors: Gould Geoffrey M. , Carter Gerald G. , Augustine Jacqueline K. 
Published: September 2019

AbstractColor‐based visual signals are important aspects of communication throughout the animal kingdom. Individuals evaluate color to obtain information about age and condition and to behave accordingly. Birds display a variety of striking, conspicuous colors and make ideal subjects for the study of color signaling. While most studies of avian color focus on plumage, bare unfeathered body parts also display a wide range of color signals. Mate choice and intrasexual competitive interactions are easily observed in lekking grouse, which also signal with prominent unfeathered color patches. Most male grouse have one pair of colorful bare part ornaments (combs), and males of several species also have inflatable air sacs in their throat. Previous studies have mostly focused on comb color and size, but little is known about the signaling role of air sac color. We measured comb size and the color properties of combs and air sacs in the Lesser and Greater Prairie‐Chickens (Tympanuchus pallidicinctus and T. cupido, respectively), and investigated whether these properties varied with age and mass. We found that mass predicted color properties of air sacs and that age predicted comb size in the Greater Prairie‐Chicken, suggesting that these ornaments indicate condition dependence. No conclusive relationships between color and age or size were detected in the Lesser Prairie‐Chicken. Color properties of both ornaments differed between the two species. Further research is needed to determine mechanisms that link condition to color and whether the information advertised by color signals from these ornaments is intended for males, females, or both.
Simulation study on the flow field of guide vane and impeller of turbo expander
Authors: Liu Bingcheng , Wang Shaoyi , Zhang Mengmeng , Liu Ning , Wang Chuanwei , Jia Wenguang 
Published: September 2019

AbstractIn the face of the current energy shortage, organic Rankine cycle (ORC) technology is a way to make efficient use of energy, especially geothermal energy. As the core component of an ORC system, a turbo expander can achieve a high conversion efficiency for geothermal energy and has good development prospects. For low temperature geothermal energy such as 95°C water, R245fa could be chosen as the working fluid. Through preliminary thermal calculations and the MATLAB programming method, the main thermal performance parameters and the aerodynamic parameters, structural parameters, and three‐dimensional modeling of the guide vane and impeller were obtained. The design of the turbo expander was modeled and meshed by the Workbench module using the ANSYS software, and the internal flow path of the expander was numerically simulated by the CFX module. The results showed that there was a small range of wake loss at the trailing edge of the vane flow; impact loss and wake loss occurred at the leading and trailing edges of the impeller blades. At the 30% relative chord strength of the impeller, there was excessive expansion, resulting in a local low‐pressure area and a secondary flow from the hub to the rim.
Effect of boiling and roasting on the physicochemical properties of Djansang seeds (Ricinodendron heudelotii)
Authors: Kinge Emmanuel Edie , Tonfack Djikeng Fabrice , Karuna Mallampalli Sri Lakshmi , Zambou Ngoufack François , Womeni Hilaire Macaire 
Published: September 2019

AbstractThis study was aimed at determining the effect of boiling and roasting on physicochemical properties of Djansang seeds. Dried Djansang seeds were divided into three groups: one group was boiled for 5, 10, and 15 min; another group was traditionally roasted for 5, 10, and 15 min, and the last group was left unprocessed and served as the control. Polyphenols were extracted from the processed seeds using the maceration method, and their content and antioxidant activity were evaluated. Oils were extracted from the dried seeds by Maceration method, and the quality was analyzed by determining their peroxide value (PV), thiobarbituric acid value (TBA), iodine value (IV), and acid value (AV). The changes in proximate composition and mineral content of the processed samples were also evaluated using standard methods. Results showed that traditional roasting significantly decreases (p < .05) the polyphenol content and antioxidant activity of Djansang seeds as compared to boiling. The analysis of oil showed that traditional roasting and boiling significantly reduce the quality of Djansang seed oil (PV: 10.85–38.49 meq O2/kg; TBA: 1.80–3.20 ppm; AV: 0.28%–0.82%; and IV: 104.27–98.11 g I2/g for roasted samples, and PV: 10.85–27.52meq O2/kg; TBA: 1.45–2.28 ppm; AV: 0.56%–0.96%; and IV: 105.87–102.96 g I2/g for boiled samples) compared to the control (PV: 9.96 meq O2/kg; TBA: 1.01 ppm; AV: 0.11%; and IV: 104.83 g I2/g) and that traditionally roasted samples were the most affected. The proximate and mineral composition of Djansang was also affected during processing. Boiling for 5 and 10 min (BNS 5 min and 10 min) and traditional roasting for 5 min (TRNS 5 min) appear to be the best processing methods of Djansang for production of Djansang‐based foods like Djansang sauce.
An Evaluation Ontology Applied to Connected Vehicle Security Assurance
Authors: Powley Stephen , Perry Simon , Holt Jon , Bryans Jeremy 
Published: September 2019

AbstractConnected vehicles have great potential to benefit society, yet create huge challenges. Vehicles, infrastructure and enterprise activities combine to form massively complex systems of systems (SoSs) that are vulnerable to cyber‐attacks. Security is ill‐defined, making it difficult to achieve a consistent, common understanding of security capabilities across the diverse industries that collaborate to develop connected vehicles. Rigorous evaluation is essential for developing strong security assurance cases. This paper contributes a model‐based systems engineering (MBSE) ontology that enables integrated evaluation processes in enterprise SoSs. The Evaluation Ontology allows diverse types of evaluation to be captured in a single integrated model. A connected vehicle security story is presented to demonstrate the value of the approach. Benefits include enhanced business intelligence that can provide a quantifiable, reportable level of confidence in security‐related processes and technologies. Further work will extend the ontology to develop a customisable suite of enabling patterns for security.
Integrating Program/Project Management and Systems Engineering in Practice
Authors: Hahn Heidi Ann , Hodges Ann L. 
Published: September 2019

AbstractTwo practitioners who have experience integrating program/project management and systems engineering conducted two workshops titled ‘Integrating Systems Engineering, Project Management, and Quality Management’ as an INCOSE Enchantment Chapter tutorial and at the 2018 International Symposium (IS18), respectively. The workshops included presentations by the researchers about their organization's integration implementations followed by small group discussion exercises on topics/issues to consider when making integration decisions. Discussion topics were drawn from Rebentisch (Ed., 2017) and included motivations to integrate, organizational environments that support or inhibit integration, influencers and influence, integration metrics, and success and failure contributors. Each exercise concluded with out‐briefs of the small groups' observations, analyses, and recommendations to the collective. A synthesis of these observations, analyses, and recommendations provide the bases for this paper.
Agile Systems Engineering Life Cycle Model for Mixed Discipline Engineering
Authors: Dove Rick , Schindel Bill 
Published: September 2019

AbstractThis article focuses on six recent understandings that have crystalized from INCOSE's Agile Systems Engineering Life Cycle Model (ASELCM) discovery project. The ASELCM project analyzed effective agile systems engineering processes in 3‐day structured analysis workshops hosted by organizations that wanted deeper understandings of what works, why it works, and how to apply those understandings across a broader base. Four case studies arising from these workshops have been published. This article cannot cover everything of interest that was discovered, but will expose six key findings: a problem‐space characterization heuristic, an asynchronous/concurrent life cycle model framework, a set of nine systems engineering operating principles, an encompassing pattern of three concurrent behavioral systems operating simultaneously in agile systems engineering, the concept of information debt, and general agile systems engineering response requirements.
Systems Engineering–Software Engineering Interface for Cyber‐Physical Systems
Authors: Sheard Sarah , Pafford Michael E. , Phillips Mike 
Published: September 2019

AbstractAlmost all of today's man‐made mechanical and electronic systems are actually cyberphysical systems (CPSs). Formerly physical systems, from rockets to hair dryers and faucets, gain capabilities from software sensing, calculating, and control. Although some software will remain mostly divorced from physical items (e.g., cloud systems), much complex software will control, sense, and communicate with physical systems, which are then called CPSs. Although many systems engineers did not come to the discipline from a software background, CPSs still need systems engineering. Additionally, software engineers must step out of their “subsystem” box and work with systems engineers to build tomorrow's systems. To enable that, systems engineers should continue to apply systems engineering principles, including continuous learning (especially about software) and coordinating (including teaching software engineers about systems engineering). The time is now to take on new behaviors to meet the challenges of CPSs. Systems engineers must work alongside software engineers to reach the joint goal of system success.
A Concept for Set‐based Design of Verification Strategies
Authors: Xu Peng , Salado Alejandro 
Published: September 2019

AbstractIn current practice, a verification strategy is defined at the beginning of an acquisition program and is agreed upon by customer and contractor at contract signature. Hence, the resources necessary to execute verification activities at various stages of the system development are allocated and committed at the beginning, when a small amount of knowledge about the system is available. However, contractually committing to a fixed verification strategy at the beginning of an acquisition program fundamentally leads to suboptimal acquisition performance. Essentially, the uncertain nature of system development will make verification activities that were not previously planned necessary, and will make some of the planned ones unnecessary. In order to cope with these challenges, this paper presents an approach to apply set‐based design to the design of verification activities to enable the execution of dynamic contracts for verification strategies, ultimately resulting in more valuable verification strategies than current practice.
Appreciative Methods Applied to the Assessment of Complex Systems
Authors: Watson Michael , Anway Randall , McKinney Dorothy , Rosser Larri Ann , MacCarthy John 
Published: September 2019

AbstractComplex systems have characteristics that challenge traditional systems engineering processes and methods. These characteristics have been defined in various ways. INCOSE has previously identified characteristics of complex systems and potential methods to deal with complexity in system development. The purpose of this paper is to provide definitions and describe distinguishing characteristics of complexity using example systems to illustrate approaches to assessing the extent of complexity. The paper applies Appreciative Inquiry to identify and assess complex system characteristics. The characteristics are used to examine several different examples of systems to illuminate areas of complexity. These examples range from seemingly simple systems to complicated systems to complex systems. Different tiers of complexity are identified as a result of the assessment. The paper also identified and introduces topics on managing complexity and the integrating system perspective that represent new directions for the engineering of complex systems. The Appreciative Inquiry approach provides a method for systems engineering practitioners to more readily identify complexity when they encounter it, and to deal more effectively with this complexity once it has been identified.
Eliciting Human Values by Applying Design Thinking Techniques in Systems Engineering
Authors: Sjøkvist Nina Marie , Kjørstad Marianne 
Published: September 2019

AbstractThe objective of this study is to investigate the effect of Design Thinking techniques for capturing and communicating human values in the early phase of Systems Engineering. To develop products, systems, or services that satisfy the stakeholders, the systems engineer (SE) must understand the emotional needs of the stakeholder. The goal is to derive stakeholder requirements from the need analysis to create solutions that satisfy the quantitative and emotional need of the stakeholders. A development project team conducts three field visits where they interview and observe stakeholders in their work environment. The project team uses visual mapping tools to communicate and discuss findings and to create a mutual understanding of the stakeholder needs. We evaluate the method using interviews, surveys, and analyses of the derived requirements. The results indicate that the team gained a better understanding of the human values and succeeded in deriving human values into stakeholder requirements.
Famous Failures Revisited: A Focus on System Integration
Authors: Armstrong James R 
Published: September 2019

AbstractA prior INCOSE paper addressed several famous failures from the viewpoint of the impact of requirements, verification, and validation. That paper has been used for pre‐reading material and initial class discussion in a course on system integration that also includes verification and validation. The discussion also notes that the original paper does not address the impact of integration on these failures. This paper adds that viewpoint and includes several other instances to develop several aspects that should be considered in systems integration.