bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved Layouts and Performance of Single- and Double-Flash Steam Geothermal Plants Generated by the Heatsep Method
Authors: Manente Giovanni , Lazzaretto Andrea 
Published: July 2020

Abstract
Single- and double-flash steam power plants are commonly used in the utilization of high enthalpy liquid-dominated geothermal resources. In these plants, the expansion line in the wet steam region results in significant penalties of turbine isentropic efficiency and power output. Accordingly, the “self-superheating” and “interstage heating” plant modifications have been recently proposed in the literature, where the saturated steam at turbine inlet is superheated by using the heat of the geothermal liquid, which is cooled before the flashing process. In this study, the aforementioned and additional new flash steam plant layouts are generated by using a systematic method, called Heatsep, for the optimum design of energy systems. All the thermal connections between consecutive basic plant components are “cut” to let these temperatures vary and in turn generate additional hot and cold streams, which are combined to enhance the overall performance of the system. It is demonstrated that the single-flash plant with self-superheating is simply obtained by cutting two out of five thermal links. In the double-flash plant, the higher number of components allows for a higher number of thermal cuts and heat integration options. Unlike the existing literature, the maximum power output is not constrained by a predefined heat transfer network. The optimization results show that the maximum power output of the novel single- and double-flash steam plants exceeds by 5.5–9.2% and 3.9–7.7% the maximum attainable by the corresponding traditional plants without internal heat integration.
Comparison of Various Blade Profiles in a Two-Blade Conventional Savonius Wind Turbine
Authors: Hassanzadeh Rahim , Mohammadnejad Milad , Mostafavi Sajad 
Published: July 2020

Abstract
Savonius turbines are one of the old and cost-effective turbines which extract the wind energy by the drag force. Nowadays, they use in urban areas to generate electricity due to their simple structure, ease of maintenance, and acceptable power output under a low wind speed. However, their efficiency is low and the improvement of their performance is necessary to increase the total power output. This paper compares four various blade profiles in a two-blade conventional Savonius wind turbine. The ratios of blade diameter to the blade depth of s/d = 0.3, 0.5, 0.7, and 1 are tested under different free-wind speeds of 3, 5, and 7 m/s and tip speed ratios (TSRs) in the range from 0.2 to 1.2. It is found that the profile of blades in a Savonius rotor plays a considerable role in power characteristics. Also, regardless of blades profile and free-wind speed, the maximum power coefficient develops in TSR = 0.8. In addition, increasing the free-wind speed enhances the rotor performance of all cases under consideration. Finally, it is revealed that the rotor with s/d = 0.5 provides maximum power coefficients in all free-wind speeds and TSR values among the rotors under consideration, whereas the rotor with s/d = 1 is the worth cases.
Heat Transfer and Secondary Flow Characteristics in a Horizontally Round Pipe for Cooling a Scramjet Combustor by Supercritical n-Decane
Authors: Li Yong , Chen Youqian , Xie Gongnan , Sunden Bengt 
Published: July 2020

Abstract
To figure out the abnormal flow characteristics and thermal performance of supercritical fluids, some detailed information of supercritical pressure n-decane flowing in a horizontally round pipe is studied in terms of secondary flow induced by the huge density change or buoyancy force. According to an evaluation of turbulence models, the shear stress transport k–ω is suitable to execute the case of horizontal flow. It is observed that the temperature distributions between the upper wall region and the lower wall region are asymmetric and the location of the maximum buoyancy force coincided with the position of Tpc (pseudo-critical temperature). The generation of a rotating flow arising from the heated wall determines the occurrence of heat transfer deterioration (HTD). In the boom stage of the HTD phenomenon, a dead zone that is close to the upper wall was formed due to the influence of vortices. In contrast, the maximum buoyancy force is located in the core flow zone and it forces the fluid in the mainstream to participate in the cooling process of the heated wall. In addition, the dead zone in the vicinity of the upper wall is broken. This is the main reason why heat transfer deterioration could be inhibited effectively.
Determination of Main-Term and Cross-Term Gas Diffusivities in Heavy Oil Systems Considering Local Oil Swelling Effect
Authors: Jang Hyun Woong , Yang Daoyong 
Published: July 2020

Abstract
To inject gas into a heavy oil reservoir, molecular diffusion of the dissolved gas into heavy oil is one of the crucial mechanisms to lower its viscosity while swelling the diluted oil. Various efforts have been made to predict the diffusivity of such gas dissolved in heavy oil with or without considering the oil swelling. Practically, the oil swelling is always considered in an excessively simplified manner so that such swelling is not able to exhibit its true effect on the estimated diffusivity. In most studies where the oil swelling is considered, the liquid-phase hydrocarbon is assumed to swell equally at every location because the height of liquid-phase in a diffusion vessel is simply extended proportionally to the oil swelling direction. Such a proportional swell is often realized during numerical solutions by uniformly extending the numerical cells, regardless of the amount of dissolved gas contained in each of them. In addition, no studies have been made to examine the contribution of one gas over the other for a gas mixture-liquid system. In this study, a pragmatic approach is proposed to determine the main- and cross-term diffusivities of gas–liquid systems considering local swelling effect. More specifically, diffusivities of CO2 and a CO2–C3H8 mixture in a Lloydminster heavy oil are respectively estimated by implementing the finite difference approximation (FDA) with the face-centered explicit scheme. For the CO2–C3H8 mixture, the individual diffusivity of each gas in the mixture is firstly computed independent of the other gas in the mixture. Then, the cross-term diffusivity is included to verify the effect of the other gas in heavy oil for the diffusion of one gas, while the local oil swelling is implemented during the estimation of the individual gas diffusivities. It is found that the obtained diffusivities of pure CO2 and each individual component of the CO2–C3H8 mixture in the Lloydminster heavy oil are reasonable and accurate to reproduce the measured oil swelling factors obtained from the dynamic volume analysis (DVA) tests.
Biochar From Cocoa Shell Pyrolysis: Potential Sorbent for CO2 Capture
Authors: Najafabadi Hamed Abedini , Ozalp Nesrin , Davis Richard A. 
Published: July 2020

Abstract
Biochar produced from slow pyrolysis of cocoa shells was studied as a sorbent for CO2 capture. Three cocoa shell samples obtained from Papua New Guinea, Peru, and Colombia were studied. Thermogravimetric analysis showed that the first three stages of degradation were quite similar for different cocoa shell sources. However, the fourth stage was different, which could be due to the different lignin content in the cocoa shell sources. Chemical analysis showed that the cocoa shell biochar had a lower content of carbon and oxygen, and a higher content of magnesium, potassium, and calcium compared with the cocoa shell. CO2 uptake performance of the cocoa shell biochar was examined and compared with a commercial activated carbon using a thermogravimeter at atmospheric pressure and ambient temperature. The final CO2 uptake after 30 min was slightly higher for cocoa shell biochar. However, activated carbon had a faster adsorption response, and it approached equilibrium faster than the cocoa shell biochar. This could be due to differences in particle size, pore structure, and surface area of the activated carbon which allows the CO2 to be adsorbed easily in its porous structure. A pseudo-second-order model of kinetics fits the CO2 adsorption behavior of cocoa shell biochar and activated carbon indicating that the rate-limiting step is chemical adsorption. Furthermore, the stability of the cocoa shell sorbent was confirmed over four adsorption/desorption cycles. By considering the simplicity of the production process and efficiency of CO2 adsorption, cocoa shell biochar can be considered a good option for CO2 capture.
Mechanics of Regular-Shape Nanomeshes for Transparent and Stretchable Devices
Authors: Vinnikova Sandra , Fang Hui , Wang Shuodao 
Published: July 2020

Abstract
Open nanomesh structures with nano/micro-scale geometric dimensions are important candidates for transparent, soft, and stretchable microelectrodes. This study developed analytical and numerical mechanics models for three types of nanomeshes that consist of regular polygons and straight traces. The analytical models described the transparency, effective stiffness, and stretchability of the nanomeshes and agree with the finite element analysis. The mechanical performances of the nanomeshes are compared based on the same level of transparency. The validated analytical expressions provide convenient guidelines for designing the nanomeshes to have levels of transparency and mechanical properties suitable for bio-integrated applications.
Probabilistic Finite Element Analysis of Cooled High-Pressure Turbine Blades—Part A: Holistic Description of Manufacturing Variability
Authors: Högner Lars , Voigt Matthias , Mailach Ronald , Meyer Marcus , Gerstberger Ulf 
Published: July 2020

Abstract
Modern high-pressure turbine (HPT) blade design stands out due to its high complexity comprising three-dimensional blade features, multipassage cooling system (MPCS), and film cooling to allow for progressive thermodynamic process parameters. During the last decade, probabilistic design approaches have become increasingly important in turbomachinery to incorporate uncertainties such as geometric variations caused by manufacturing scatter and deterioration. Within this scope, the first part of this two-part article introduces parametric models for cooled turbine blades that enable probabilistic finite element (FE) analysis taking geometric variability into account to aim at sensitivity and robustness evaluation. The statistical database is represented by a population of more than 400 blades whose external geometry is captured by optical measurement techniques and 34 blades that are digitized by computed tomography (CT) to record the internal geometry and the associated variability, respectively. Based on these data, parametric models for airfoil, profiled endwall (PEW), wedge surface (WSF), and MPCS are presented. The parametric airfoil model that is based on the traditional profile theory is briefly described. In this regard, a methodology is presented that enables to adapt this airfoil model to a given population of blades by means of Monte Carlo-based optimization. The endwall variability of hub and shroud are parametrized by radial offsets that are applied to the respective median endwall geometry. WSFs are analytically represented by planes. Variations of the MPCS are quantified based on the radial distribution of cooling passage centroids. Thus, an individual MPCS can be replicated by applying adapted displacement functions to the core passage centroids. For each feature that is considered within this study, the accuracy of the parametric model is discussed with respect to the variability that is present in the investigated blade population and the measurement uncertainty. Within the scope of the second part of this article, the parametric models are used for a comprehensive statistical analysis to reveal the parameter correlation structure and probability density functions (PDFs). This is required for the subsequent probabilistic finite element analysis involving real geometry effects.
Deficiencies in the Spalart–Allmaras Turbulence Model for the Prediction of the Stability Boundary in Highly Loaded Compressors
Authors: Moreno Jose , Dodds John , Stapelfeldt Sina , Vahdati Mehdi 
Published: July 2020

Abstract
Reynolds-averaged Navier–Stokes (RANS) equations are employed for aerodynamic and aeroelastic modeling in axial compressors. Their solutions are highly dependent on the turbulence models for closure. The main objective of this work is to assess the widely used Spalart–Allmaras model suitability for high-speed compressor flows. For this purpose, an extensive investigation of the sources of uncertainties in a high-speed multi-stage compressor rig was carried out. The grid resolution near the casing end wall, which affects the tip leakage flow and casing boundary layer, was found to have a major effect on the stability limit prediction. Refinements in this region led to a stall margin loss prediction. It was found that this loss was exclusively due to the destruction term in the SA model.
The Track, Hotspot and Frontier of International MOOC Research 2008–2018 — A Scientometric Analysis Based on SCI and SSCI
Authors: Zhang Wei , Zhao Liang 
Published: July 2020

The aim of this paper is to objectively present the development and trend of international MOOC research. Metadata taken from 660 literature records is used to visualize the state of MOOC research. The records were published between 2008 and 2018, and Citespace software is employed to visualize key data about the research contained on the SCI and SSCI platform. It has the following findings. First, since 2012, the number of international MOOC research papers and cited frequency has shown an upward trend. The research force was mainly concentrated in North America, Europe and Asia, and the publishing institutions were mainly concentrated in Universities of various countries, and formed a more obvious international cooperation network. Second, journals such as [Formula: see text]INT REV RES OPEN DIS[Formula: see text] and [Formula: see text]COMPUTERS & EDUCATION[Formula: see text] are the foundational literatures of MOOC research. George Siemens, Stephen Downes, John Daniel and others have made important contributions to the foundation research of MOOC. Third, Breslow, Liyanagunawardena et al. were cited more frequently and formed eight research clusters such as teaching interaction, relativism/behaviorism theory, individualized learning and diversified education. Fourth, distance education, online learning, learning situation analysis, curriculum construction and platform construction are the hot topics of international MOOC research in the recent decade. Fifth, the development of international MOOC has spread to various disciplines and promoted the interdisciplinary research of environment, biology, medicine, philosophy, psychology and other disciplines.
Australian Veterans of the Middle East Conflicts 2001–2010: Select Reproductive Health Outcomes Part 2 — Prenatal, Fetal, and Neonatal Outcomes
Authors: Warner Rachelle , Avery Jodie C. , Neuhaus Susan , Davies Michael J. 
Published: July 2020

Background: Following on from Part 1 of these companion articles, which described the maternal and paternal cohort of the Middle East Area of Operations (MEAO) Census Study, this manuscript aims to describe fetal and infant characteristics and outcomes from the self-report data, including live deliveries, stillbirths, all other pregnancy losses, and unknown outcomes. Methods: A descriptive analysis was performed on the clinical variables where data were reported. Descriptive statistics (means, frequencies, percentiles) were used to describe the occurrence of adverse gestational outcomes. Odds ratios were also calculated for perinatal outcomes. Infant characteristics and outcomes were evaluated using statistical analysis software IBM SPSS v26. Results: There were 15,417 pregnancies reported by respondents to the MEAO Census Study. Of these, 74% (11,367) resulted in a live delivery, 0.75% in a stillbirth, and 20% in another type of pregnancy loss (ectopic pregnancy, miscarriage, termination). The unadjusted odds of an adverse perinatal outcome were higher in the MEAO Census population than in the general Australian population, notably stillbirth (OR = 3.11, 95% CI 2.56–3.80), perinatal death (OR = 3.80, 95% CI 3.26–4.44), and neonatal death (OR = 5.43, 95% CI 4.27–6.91). There were 499 cases of birth defects reported and 85 cases of childhood cancer in the MEAO population. The unadjusted odds of childhood cancer were slightly higher (OR = 1.7, 95% CI 0.09–3.28) in the MEAO population, and the unadjusted odds of birth defects were lower (OR = 0.52, 95% CI 0.40–0.68). The male:female infant sex ratio of babies born to respondents was 102 (5939 males:5823 females). Conclusions: The MEAO Census Study presents a generally reassuring picture of reproductive health for women serving in the Australian Defence Force with regards to the risk of pregnancy loss and perinatal outcomes. The increased odds of perinatal and neonatal death and stillbirth are worthy of further study and evaluation, as is the increase in likelihood of childhood cancer in the offspring of MEAO veterans.
Suppression of ABCE1-Mediated mRNA Translation Limits N-MYC–Driven Cancer Progression
Authors: Gao Jixuan , Jung MoonSun , Mayoh Chelsea , Venkat Pooja , Hannan Katherine M. , Fletcher Jamie I. , Kamili Alvin , Gifford Andrew J. , Kusnadi Eric P. , Pearson Richard B. , Hannan Ross D. , Haber Michelle , Norris Murray D. , Somers Klaartje , Henderson Michelle J. 
Published: July 2020

Abstract

The ability of the N-MYC transcription factor to drive cancer progression is well demonstrated in neuroblastoma, the most common extracranial pediatric solid tumor, where MYCN amplification heralds a poor prognosis, with only 11% of high-risk patients surviving past 5 years. However, decades of attempts of direct inhibition of N-MYC or its paralogues has led to the conclusion that this protein is “undruggable.” Therefore, targeting pathways upregulated by N-MYC signaling presents an alternative therapeutic approach. Here, we show that MYCN-amplified neuroblastomas are characterized by elevated rates of protein synthesis and that high expression of ABCE1, a translation factor directly upregulated by N-MYC, is itself a strong predictor of poor clinical outcome. Despite the potent ability of N-MYC in heightening protein synthesis and malignant characteristics in cancer cells, suppression of ABCE1 alone selectively negated this effect, returning the rate of translation to baseline levels and significantly reducing the growth, motility, and invasiveness of MYCN-amplified neuroblastoma cells and patient-derived xenograft tumors in vivo. The growth of nonmalignant cells or MYCN-nonamplified neuroblastoma cells remained unaffected by reduced ABCE1, supporting a therapeutic window associated with targeting ABCE1. Neuroblastoma cells with c-MYC overexpression also required ABCE1 to maintain cell proliferation and translation. Taken together, ABCE1-mediated translation constitutes a critical process in the progression of N-MYC–driven and c-MYC–driven cancers that warrants investigations into methods of its therapeutic inhibition.

Significance:
These findings demonstrate that N-MYC–driven cancers are reliant on elevated rates of protein synthesis driven by heightened expression of ABCE1, a vulnerability that can be exploited through suppression of ABCE1.
Mathematical Modeling Provides Evidence for Niche Competition in Human AML and Serves as a Tool to Improve Risk Stratification
Authors: Stiehl Thomas , Wang Wenwen , Lutz Christoph , Marciniak-Czochra Anna 
Published: July 2020

Abstract

Acute myeloid leukemia (AML) is a stem cell–driven malignant disease. There is evidence that leukemic stem cells (LSC) interact with stem cell niches and outcompete hematopoietic stem cells (HSC). The impact of this interaction on the clinical course of the disease remains poorly understood. We developed and validated a mathematical model of stem cell competition in the human HSC niche. Model simulations predicted how processes in the stem cell niche affect the speed of disease progression. Combining the mathematical model with data of individual patients, we quantified the selective pressure LSCs exert on HSCs and demonstrated the model's prognostic significance. A novel model-based risk-stratification approach allowed extraction of prognostic information from counts of healthy and malignant cells at the time of diagnosis. This model's feasibility was demonstrable based on a cohort of patients with ALDH-rare AML and shows that the model-based risk stratification is an independent predictor of disease-free and overall survival. This proof-of-concept study shows how model-based interpretation of patient data can improve prognostic scoring and contribute to personalized medicine.

Significance:
Combining a novel mathematical model of the human hematopoietic stem cell niche with individual patient data enables quantification of properties of leukemic stem cells and improves risk stratification in acute myeloid leukemia.
Circadian Rhythm Is Disrupted by ZNF704 in Breast Carcinogenesis
Authors: Yang Chao , Wu Jiajing , Liu Xinhua , Wang Yue , Liu Beibei , Chen Xing , Wu Xiaodi , Yan Dong , Han Lulu , Liu Shumeng , Shan Lin , Shang Yongfeng 
Published: July 2020

AbstractCopy number gain in chromosome 8q21 is frequently detected in breast cancer, yet the oncogenic potential underlying this amplicon in breast carcinogenesis remains to be delineated. We report here that ZNF704, a gene mapped to 8q21, is recurrently amplified in various malignancies including breast cancer. ZNF704 acted as a transcriptional repressor and interacted with the transcriptional corepressor SIN3A complex. Genome-wide interrogation of transcriptional targets revealed that the ZNF704/SIN3A complex represses a panel of genes including PER2 that are critically involved in the function of the circadian clock. Overexpression of ZNF704 prolonged the period and dampened the amplitude of the circadian clock. ZNF704 promoted the proliferation and invasion of breast cancer cells in vitro and accelerated the growth and metastasis of breast cancer in vivo. Consistently, the level of ZNF704 expression inversely correlated with that of PER2 in breast carcinomas, and high level of ZNF704 correlated with advanced histologic grades, lymph node positivity, and poor prognosis of patients with breast cancer, especially those with HER2+ and basal-like subtypes. These results indicate that ZNF704 is an important regulator of the circadian clock and a potential driver for breast carcinogenesis.Significance:This study indicates that ZNF704 could be a potential oncogenic factor, disrupting circadian rhythm of breast cancer cells and contributing to breast carcinogenesis.