bluuebunny/crossref_metadata_2025_split huggingface dataset:
Calculation of ternary liquid‐liquid equilibrium data using arc‐length continuation
Authors: Binous Housam , Bellagi Ahmed 
Published: September 2020

AbstractLiquid‐liquid extraction is an important separation technique used in several chemical engineering processes. When experimental data are unavailable, reliable prediction of liquid‐liquid equilibrium (LLE) data is essential for the optimal design of these processes. This paper describes a new methodology based on the application of the arc‐length continuation numerical technique in order to compute LLE data using non‐random two liquid or universal quasi‐chemical activity coefficient models. This technique is straightforward to implement in Mathematica©. In addition, the arc‐length method avoids the main disadvantage of root finding methods, such as Newton's method, for which the convergence often depends on the proper choice of an initial guess. Another advantage of the proposed approach, based on arc‐length continuation, is that all LLE data are generated in one single calculation. Several case studies, involving the three main types of ternary systems (ie, Type I, II and 0), illustrate the proposed method. For type I, we study the following three ternary systems: (1) water‐ethanol‐benzene, (2) 5‐hydroxymethylfurfural‐1‐butanol‐water, and (3) methanol‐benzene‐water. We have selected, for type II systems, the following mixtures: (1) isobutyl alcohol‐cyclohexane‐water, (2) methanol‐cyclohexane‐water, and (3) 4‐methyl‐2‐pentanone‐2‐butanol‐water. For type 0 systems, we have chosen a mixture composed of DMSO‐THF‐water. Finally, for each case, our predicted results are benchmarked against the corresponding experimental data.
Accurate characterization of full pore size distribution of tight sandstones by low‐temperature nitrogen gas adsorption and high‐pressure mercury intrusion combination method
Authors: Fu Shuaishi , Fang Qi , Li Aifen , Li Zhiping , Han Jinliang , Dang Xu , Han Wencheng 
Published: September 2020

AbstractThe full pore size distribution represents the integrated characteristics of micro‐nano pore‐throat systems in tight reservoirs. And it involves experiments of different scales to fully analyze the microscope properties. In this paper, we established a new approach for full pore size characterization through conducting the high‐pressure mercury intrusion (HPMI) experiments and low‐temperature nitrogen gas adsorption (LTN2GA) experiments. Meanwhile, we studied the petrology feature of the tight sandstones through X‐ray diffraction (X‐rD) and TESCAN Integrated Mineral Analyzer (TIMA). Then, we investigated the HPMI capillary pressure curves and pore size distribution characteristics, as well as the adsorption‐desorption isotherms features and BET‐specific surface area. Finally, the BJH, non‐local density functional theory (NLDFT) and the quenched solid density functional theory (QSDFT) are contrasted for analyzing the adsorption and pore size distribution characteristics. The HPMI method characterizes the macropores distribution accurately, and the micro/mesopores take up of 14.47% of the total pore spaces. The physisorption isotherms take on the combining shape of type II and IV(a), and the hysteresis loops are like type H3 combined with H4. The BET‐specific surface area is inversely proportional to permeability, and the constant of adsorption heat shows consistence with the analysis results of mineral content. QSDFT can characterize the pore size distribution of micro/mesopores more accurately than the BJH, HPMI, and NLDFT method. By combining the pores narrower than 34 nm calculated from QSDFT method and pores larger than 34 nm calculated from HPMI data with mercury intrusion pressure lower than 42.65 MPa, the full pore size distribution features of tight sandstones are accurately characterized. The micro/mesopores from the new combination method are 3.72% more than that calculated from the HPMI data, and it is of great significance for the accurate pore distribution evaluation and development of tight reservoirs.
Solar photovoltaic and batteries have unaffordable environmental and economic costs
Authors: Boretti Alberto 
Published: September 2020

AbstractThe current renewable energy technologies do not permit a better economy and do not permit a better environment. Solar PV and wind energy production suffer from intermittency and unpredictability, and in countries such as Saudi Arabia, where water is scarce, the huge energy storage needed to make a grid wind and solar only may only be covered by batteries. These batteries have an unacceptably high economic and environmental cost to add to the already everything but negligible economic and environmental costs of solar PV and wind. Here we demonstrate as to produce in Saudi Arabia the same energy of a combined cycle gas turbine (CCGT) plant by using solar PV power plants and battery energy storage facilities translates into much larger environmental and economic costs, with also unfavorable energy security and depletion of natural resources. It is therefore important to invest more in research for novel renewable energy technologies including internal storage, such as higher temperature concentrated solar power plants with enhanced thermal energy storage by liquid metals and high efficiency advanced ultra‐supercritical steam cycles and supercritical CO2cycles, that may deliver capacity factor of 100% permitting independence from the resource variability.
High-Frequency Sampling of Small Streams in the Agroecosystems of Southwestern Ontario, Canada, to Characterize Pesticide Exposure and Associated Risk to Aquatic Life
Authors: Sanford M. , Prosser R.S. 
Published: September 2020

Abstract
The temporal dynamics of pesticide concentrations in streams remains poorly characterized in southwestern Ontario, a region of the province where land use is dominated by agriculture. Understanding the magnitude and duration of pulsed exposures to pesticides in these small streams is critical when estimating the risk of pesticides to these aquatic ecosystems. The present study investigated the application of a high-frequency water sampling approach paired with the collection of flow data to characterize the pulsed exposure of pesticides to small streams in southwestern Ontario. Six sites along 2 different streams with different magnitudes of agricultural land use in their upstream catchments were sampled using half-day composite samples from July to October 2018 and from May to September 2019. A total of 1043 samples were collected over the 2 yr, of which 210 were analyzed. Samples for analysis were chosen based on flow, water level, and precipitation data. Liquid and gas chromatography coupled with tandem mass spectrometry was used to measure &gt;500 pesticides in each water sample. A total of 35 different compounds were detected over the 6 sampling sites. For pesticides that were detected in &gt;10% of water samples above the method quantification limit, a deterministic risk assessment using water quality guidelines and a probabilistic risk assessment using species sensitivity distributions were performed. The calculated hazard quotients showed that 2,4-D, atrazine, metolachlor, and metribuzin exceeded a level of concern of 1 at the highest concentrations detected. In all cases, hazard concentrations that would be protective of 95% of species from the species sensitivity distributions were greater than the 95th centile of the environmental exposure distributions, meaning that the risk from the pesticides was low. Environ Toxicol Chem 2020;39:2570–2587. © 2020 SETAC
Improved survival for individuals with common chronic conditions in the Medicare population
Authors: Goldman Dana P. , Cohen Benjamin G. , Ho Jessica Y. , McFadden Daniel L. , Ryan Martha S. , Tysinger Bryan 
Published: September 2020

AbstractIt is well established that the United States lags behind peer nations in life expectancy, but it is less established that there is heterogeneity in life expectancy trends. We compared mortality trends from 2004 to 2014 for the United States with 17 high‐income countries for persons under and over 65. The United States ranked last in survival gains for the young but ranked near the middle for persons over 65, the group with universal access to public insurance. To explore the over‐65 mortality trend, we estimated Cox proportional hazards models for individuals soon after entering Medicare. These were estimated separately by race and sex, controlling for 26 chronic conditions and condition‐specific time trends. The separate regressions enabled survival comparisons for the 2004 and 2014 cohorts by race and sex, conditional on baseline health. We predicted 5‐year survival for all combinations of diabetes, hyperlipidemia, hypertension, and ischemic heart disease (IHD). All 16 combinations of these conditions showed survival gains, with diabetes as a key driver. Notably, survival improved and racial disparities narrowed for individuals with diabetes, hypertension, and IHD. White females, black females, white males, and black males gained 3.61, 3.90, 3.57, and 5.89 percentage points in 5‐year survival, respectively.
Impact of age and comorbidity on survival among patients with oral cavity squamous cell carcinoma
Authors: Patel Krupal B. , Martin Daniel , Zhao Songzhu , Kumar Bhavna , Carrau Ricardo , Ozer Enver , Agrawal Amit , Kang Stephen , Rocco James W. , Schuller David , Teknos Theodoros , Brock Guy , Old Matthew 
Published: September 2020

AbstractObjectiveTo identify predictors of overall survival (OS) and to stratify patients according to significant prognostic variables.MethodsA retrospective study of 274 consecutive patients with primary Oral Cavity Squamous Cell Carcinoma. Kaplan‐Meier, Cox proportional hazard models, and recursive partitioning analysis (RPA) were used for analysis of OS. These results were further validated using National Cancer Database cohort of 21 895 patients.ResultsMedian OS was 3.65 years. T‐classification and N‐classification, alcoholic beverages/week, age, and adjuvant treatment were significant predictors of OS. RPA identified high‐risk subpopulations: N0‐1 patients with CCI ≥ 4.5 and N2‐3 patients ordered by those not receiving adjuvant treatment, those with T3‐4 disease despite adjuvant therapy, and those having T1‐2 disease with adjuvant therapy.ConclusionsThis study utilized significant prognostic indicators and RPA to highlight the importance of age, N‐classification, T‐classification, comorbidity, and adjuvant therapy in conjunction with American Joint Committee on Cancer staging to improve preoperative counseling.
Is it possible to halve the incidence of liver cancer in China by 2050?
Authors: Shi Ju‐Fang , Cao Maomao , Wang Yuting , Bai Fang‐Zhou , Lei Lin , Peng Ji , Feletto Eleonora , Canfell Karen , Qu Chunfeng , Chen Wanqing 
Published: September 2020

AbstractA substantial proportion of liver cancers is attributable to chronic infection with hepatitis B and C (HBV/HCV). Liver cancer could become the second cancer, after cervical, to be effectively controlled globally, if proven interventions such as vaccination can be implemented on a large scale. In 2018, the global mortality rate for liver cancer was estimated to be 8.5 per 100 000 individuals. Given patterns of HBV infection and immigration across countries, liver cancer control requires combined, global action. Liver cancer trends vary between countries, in some Western countries, the incidence rates were relatively low but have increased in recent decades; conversely, in several Asian countries, the incidence rates have decreased over time. China has in the past contributed more than half of the global burden of liver cancer but more recently a national decline in liver cancer incidence has been observed. Here, we review the liver cancer burden and exposure to risk factors in China, compared to other countries. We also review the implementation status for primary and secondary prevention interventions and major outcomes achieved over the past three decades. Using Bayesian age‐period‐cohort analysis, we examine recent trends and based on these, predict that by 2050, the incidence of liver cancer in China could fall by half. We additionally survey the literature to identify current research needs, and review relevant national policies on liver cancer control in China. A comprehensive set of interventions is proposed to progress toward the long‐term goal of liver cancer elimination based on the natural history and evidence‐based interventions.
Employing Model Based Conceptual Design to Identify Test Range Resources Required to Validate the Delivered Solution
Authors: Flanigan David , Robinson Kevin 
Published: September 2020

AbstractDuring an initial system concept development, systems engineers will look at different areas of the problem space in order to develop a solution that will satisfy the overall capabilities defined by the stakeholders. During this phase, the problem space is intentionally left large in order to consider a larger scope of the solution space and operational environment. Thus, the SE would like to consider as much of the space as possible to determine what is feasible and infeasible when progressing on to the next phase of system development. This paper reports on an extension of Model Based Conceptual Design (MBCD) that visualizes the potential feasible solution space in order to inform decision makers of feasible solutions and test range resources required to validate the delivered solution. An approach is offered, utilizing Design of Experiments methods, to extend previous research on test and evaluation with MBCD as applied to an illustrative use case.
A sustainable software testing process for the Square Kilometre Array project
Authors: Brajnik Giorgio , Bartolini Marco , Rees Nicholas 
Published: September 2020

AbstractIn this paper we show how to achieve a sustainable software testing process in a very complex scientific project, the Square Kilometre Array (SKA) radio observatory. The project currently involves 13 countries, 16 agile development teams of about 150 individuals, governed through the Scalable Agile Framework (SAFe) framework; the software that is being built ranges from user interfaces to control systems, from transactional applications to high performance parallel scientific processing code.The paper illustrates the testing challenges we have to tackle; it also defines what a “sustainable testing process” is and how that constitutes the foundation of an incremental adoption plan rooted on systems thinking. The plan is then described, highlighting the principles we adhered to for synthesising a sequence of 9 basic testing goals that are currently being rolled out.We are confident that similar decisions can be made on many large scientific projects that are developed with agile methods.
Toward Architecting the Future of System Security
Authors: Willett Keith D. 
Published: September 2020

AbstractCybersecurity is not just a technical decision regarding cost, benefit, and performance. Cybersecurity interweaves with civil liberties (opting out of the digital world), privacy (the right to be unobserved and the right to be forgotten), automated resolution of moral dilemmas (autonomous vehicle choosing who to hit), financial security (wealth representation being bits on a hard drive), socio‐political deception (detecting fake news on which we base life decisions), and physical safety (loss of life and property from adverse cyber‐physical events). As we look to the future of system security and system security engineering, we have hard choices to make that effect the way we live. This paper examines many of those choices and establishes architectural premises toward architecting the future of system security.
The Greatest Young System Engineers of the Year Challenge
Authors: Sparrius Ad 
Published: September 2020

AbstractIn 2015 the Greatest Young Systems Engineers of the Year Challenge was launched as part of the INCOSE SA annual conference. This annual challenge has now occurred five times from 2015 through 2019/20 with a total of 84 contestants from nine employer companies. This paper summarizes the challenge's objectives, its results, and explains the lessons learnt.
Engaging Mechanical Engineers in System Modeling
Authors: Gullhav Katrine , Haskins Cecilia 
Published: September 2020

AbstractIn Model Based Systems Engineering (MBSE) the system model is used to capture and share Systems Engineering (SE) data and artifacts. Using the model to communicate with the project engineers is found to be more successful with software (SW) engineers than with other domains. As a result, the system model is developed unevenly.This article reports on how a company, whose system model is decisively more detailed in its description of SW sub‐systems, might better involve mechanical (and other) engineers in system modeling. Case‐based research is applied to understand the company's challenges. The conclusion is that the challenges originate from failing to consider the differences in how these domains view and relate to a system under development. The research determined that the models developed in the company‐specific tool implementation were incapable of producing useful deliverables for non‐software engineers. In the absence of a plan for how a mechanical engineer could access information from the model, the authors recommend defining a modeling environment to ensure the necessary contributions from both systems engineers and mechanical engineers.
Complexity, Systems Thinking and an Integrated Systems Engineering and Project Management Model
Authors: Jonkers Raymond Klaas , Shahroudi Kamran Eftekhari 
Published: September 2020

AbstractAlthough theory and guiding principles exist for the integration of systems engineering and project management, there does not appear to be a practical approach offered. With unproductive tension, discipline‐specific disparate processes and models, and persistent project failures, there is a need for a paradigm shift in the approach to this integration. This shift may be achieved through systems thinking and the use of an integrated management model that includes key linkages, a decision support system and system dynamics. The model presented in the current study provides a structured approach for multiple disciplines to address and manage product and project complexity through cross‐functional processes within an interactive dynamic model environment consisting of system, process and policy levers. The model is validated through application of a case study, literature review, surveys and interviews with industry experts. Use of the model provides for critical thinking and a multi‐disciplinary agile approach to help navigate complexity.
Implementing Model‐Based Systems Engineering for the Development and Support of an Additive‐Layer Manufacturing Plant in the Aerospace Context
Authors: Hussein Elmouiz , Kossmann Mario 
Published: September 2020

AbstractOne of the revolutionary changes of the 21st century in the aerospace industry is the emergence of Additive Layer Manufacturing or 3D printing technology. This is so for a number of reasons. There is virtually no material waste in the production process. Existing aircraft parts of current designs can be produced in less time and for a fraction of the cost, whilst still meeting the ‘form, fit and function’ requirements of those existing parts. Modified parts that are stronger and lighter, but which could not previously be produced with traditional manufacturing methods and tools, can be designed and produced. Going even beyond parts, new designs will increasingly be enabled with larger ALM machines that are capable of printing much larger components, which have most of the traditional parts already integrated. This dramatically reduces manufacturing and assembly times and costs, as well as weight, while increasing the level of functional integration by such components.This paper reports on the application of MBSE for the development and support of a new ALM Plant in the UK. The establishment of this ‘ALM System’ followed years of cutting‐edge research activities on laser and electron beam powder bed technologies. The requirements for and the solution architecture of the ALM System were developed using various methods and supporting tools, until the requirements cascade and part of the corresponding system design, down to the level of certain detailed production processes, was modeled in SysML using MagicDraw.
Preparing the Acquisition Workforce: A Digital Engineering Competency Framework
Authors: Pepe Kara , Hutchison Nicole , Blackburn Mark , Verma Dinesh , Wade Jon , Peak Russell , Baker Adam , Whitcomb Cliff , Khan Rabia 
Published: September 2020

AbstractThis paper describes the goals, methods, approaches, and preliminary results of research to develop a Digital Engineering Competency Framework (DECF) for the acquisition workforce. Evidence across the Services and industry has affirmed digital engineering is a critical practice necessary to support acquisition in an environment of increasing global challenges, dynamic threats, rapidly evolving technologies, and increasing life expectancy of our systems currently in operation. The purpose of the DECF is to provide clear guidance for the DoD acquisition workforce, in particular the engineering (ENG) acquisition workforce, through clearly defined competencies that illuminate the knowledge, skills, abilities, and behaviors required for digital engineering professionals.
SKA Maintenance and Support Modeling
Authors: Taljaard Cornelius , Chrysostomou Antonio , van Zyl Andreas N 
Published: September 2020

AbstractThe availability requirement for the SKA telescopes will have a major impact on the design, capital and operating costs. The design‐for‐reliability, maintainability, maintenance planning and performance expectations should be well balanced.Engineering analysis indicates that the SKA telescopes should have an inherent availability of 99% and both telescopes are required to have an operational availability of at least 95%.This paper discusse the availability and support challenges of building and operating two telescopes in Australia and South Africa. It describes the approach to the critical design review of the system, with a special focus on simulation modeling and sensitivity analysis.It also discusses the use of failure data from the precursor telescopes and gives technical insight into the development of a digital twin for decision making.
Investigating Organization Attributes that Support Systems Engineering Workforce Effectiveness
Authors: Hutchison Nicole , Burke Pamela , Tao Hoong Yan See , Makwana Deep , Giffin Ralph , Verma Dinesh 
Published: September 2020

AbstractThis paper describes a multi‐year effort to understand the attributes of organizations that support systems engineering effectiveness. Using a combination of surveys, interviews, and commercially available culture assessment tools, the research identifies key components of organization culture, structure, governance, process, and tools that enable systems engineers to deliver value in industry and government contexts in the United States and Europe. The results can be used by people to improve effectiveness in their own organizations and to stimulate discussion and action to support effectiveness across the profession.