bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation and CMAS Wettability Investigation of CMAS Corrosion Resistant Protective Layer with Micro-Nano Double Scale Structure
Authors: Wang Yihao , Xu Zhenning , Wang Weize , Zhang Chengcheng , Yu Zexin , Fang Huanjie , Yang Ting
Published: May 2022

Solution precursor plasma spray (SPPS) can prepare thermal barrier coatings (TBCs) with nanostructures, which can modify the adhesion and wettability of molten silicate environmental deposits (CMAS) on the surface of TBCs, thereby improving the resistance of TBCs to CMAS corrosion. In this study, SPPS layers with micro-nano double scale structures were prepared on the surface of conventional atmospheric plasma spraying (APS) coatings. The effect of process parameters on the micro-nano double scale structures and the wetting and infiltration behavior of molten CMAS on the surface of coatings were investigated. The results show that micron structure is more sensitive to process parameters. Lower precursor viscosity, closer spraying distance, and smoother APS layer are favorable to form more typical and dense micron structures. After covering the SPPS layer, the CMAS wetting diameter is reduced by about 40% and the steady-state contact angle increased up to three times. The reason is that the micro-nano double scale structures can effectively trap air and form an air layer between the coating surface and the molten CMAS. In addition, nano-particles play a more important role in the formation of the air layer, which in turn determines the steady-state wettability properties. While micron structures can influence the time needed to reach the steady state. However, the SPPS layers composed of nano-particles have a very loose structure and weak cohesion, and they degrade and fail rapidly after the infiltration of molten CMAS. Therefore, maintaining the excellent CMAS wetting resistance of the SPPS layers while taking into account their lifetime and reliability has become the focus of further research.
Optical Switches for Lipid Membranes: Computed Molecular Projection Area as a Switch Selection Criterion
Authors: Boldyrev Ivan
Published: May 2022

Optical switches in lipid membranes are an emerging tool to tune the properties of the bilayer or membrane protein integrated therein. Here, we use simple geometry and physics considerations to deduce structural criteria to design efficient photoactivated switches for lipid membranes. We compare how the area of projection on the bilayer of various classes of photoswitches changes upon the trans/cis or open/closed transition and show that azobenzene and stilbene should distort the bilayer structure the most. We also conclude that planar-elongated molecules, in which atoms of isomerizable double bond have no additional substituents, while substituents of the fragments adjacent to the double bond prevent formation of the planar molecule in cis configuration, are to be the best photoswitches for lipid membranes.
First-Principles Investigations on Structural Stability, Elastic Properties and Electronic Structure of Mg32(Al,Zn)49 Phase and MgZn2 Phase
Authors: Song Yu , Zhan Songtao , Nie Baohua , Qi Haiying , Liu Fangjun , Fan Touwen , Chen Dongchu
Published: May 2022

Al–Mg–Zn alloys reinforced by T–Mg32(Al,Zn)49 phase had higher structure stability and strength than Al–Zn–Mg–(Cu) alloys reinforced by MgZn2 phase, but the reasons for these two kind of alloys was not well-known. To reveal the discrepancy between T phase and MgZn2 phase, the lattice parameters, cohesive energy, and electronic structure as well as the elastic properties were investigated based on density functional theory. Four types of T phase unit cell were employed according to symmetry of space group. The calculated lattice constants well-agreed with experimental data. Compared to MgZn2 phase, T phases obtained lower cohesive energy owing to their partial covalent bond, which may result in a higher structure stability. The elastic modulus E of T phase depended on the occupation of Al atom, and the effect of the occupation of Al atom on the structure and properties of T phase was also discussed.
Scalable Fabrication of Nanogratings on GaP for Efficient Diffraction of Near-Infrared Pulses and Enhanced Terahertz Generation by Optical Rectification
Authors: Bashirpour Mohammad , Cui Wei , Gamouras Angela , Ménard Jean-Michel
Published: May 2022

We present a process flow for wafer-scale fabrication of a surface phase grating with sub-micron feature sizes from a single semiconductor material. We demonstrate this technique using a 110-oriented GaP semiconductor wafer with second-order nonlinearity to obtain a nanostructured device (800 nm lateral feature size and a 245 nm height modulation) with applications relevant to near-infrared optical diffraction and time-resolved terahertz (THz) technologies. The fabrication process involves a plasma-enhanced chemical deposition of a SiO2 layer on the wafer followed by contact photolithography and inductively coupled plasma reactive ion etching (ICP-RIE). We discuss the required radiation dosage, exposure times, temperatures and other key parameters to achieve high-quality nanogratings in terms of filling ratio, edge profile, and overall shape. The phase-grating properties, such as the pitch, spatial homogeneity, and phase retardation, are characterized with an atomic force microscope, scanning electron microscope and a non-invasive optical evaluation of the optical diffraction efficiency into different orders. We demonstrate an application of this device in a time-domain THz spectroscopy scheme, where an enhanced THz spectral bandwidth is achieved by optical rectification of near-infrared laser pulses incident on the grating and efficiently diffracted into the first orders. Finally, the reported process flow has the potential to be applied to various materials by considering only slight adjustments to the ICP-RIE etching steps, paving the way to scalable fabrication of sub-micron patterns on a large range of substrates.
Megaprosthesis for Metastatic Bone Disease—A Comparative Analysis
Authors: Thorkildsen Joachim , Strøm Thale Asp , Strøm Nils Jørgen , Sellevold Simen , Norum Ole-Jacob
Published: May 2022

Background: Megaprosthetic reconstruction is sometimes indicated in advanced metastatic bone disease (MBD) of the appendicular skeleton with large degrees of bone loss or need for oncological segmental resection. Outcome after megaprosthetic reconstruction was studied in the setting of primary bone sarcoma with high levels of complications, but it is not known if this applies to MBD. Method: We performed a comparative analysis of complications and revision surgery for MBD and bone sarcoma surgery in an institutional cohort from 2005–2019. Presented are the descriptive data of the cohort, with Kaplan–Meier (K–M) rates of revision at 1, 2 and 5 years together with a competing risk analysis by indication type. Results: Rates of revision surgery are significantly lower for MBD (8% at 1 year, 12% at 2 years), in the intermediate term, compared to that of sarcoma (18% at 1 year, 24% at 2 years) (p = 0.04). At 5 years this is not significant by K–M analysis (25% for MBD, and 33% for sarcoma), but remains significant in a competing risk model (8% for MBD, and 20% for sarcoma) (p = 0.03), accounting for death as a competing event. Conclusion: Rates of revision surgery after megaprosthetic reconstruction of MBD are significantly lower than that for primary bone sarcoma in this cohort.
Gamification in Tourism: A Design Framework for the TRIPMENTOR Project
Authors: Roinioti Elina , Pandia Eleana , Konstantakis Markos , Skarpelos Yannis
Published: May 2022

In this paper, we discuss the gamification strategies and methodologies used by TRIPMENTOR—a game-oriented cultural tourism application in the region of Attica. Its primary purpose is to provide visitors with rich media content via the web and mobile environments by redirecting travellers, highlighting points of interest, and providing information for tour operators. Gamification is a critical component of the project; it relates users to specific sites and activities, improves their visiting experiences, and encourages a constant interaction with the application through a playful experience. In TRIPMENTOR, gamification serves both as a tourism marketing strategy and as a tool for encouraging users to share their experiences while exploring Attica in a way designed to meet their personal needs, interests, and habits. This paper aims to describe and analyse the gamification mechanisms applied, following the Octalysis framework, and discuss the opportunities and challenges of gamification as a tourist marketing strategy.
Behavior Variations and Their Implications for Popularity Promotions: From Elites to Mass on Weibo
Authors: Shi Bowen , Xu Ke , Zhao Jichang
Published: May 2022

The boom in social media with regard to producing and consuming information simultaneously implies the crucial role of online user influence in determining content popularity. In particular, understanding behavior variations between the influential elites and the mass grassroots is an important issue in communication. However, how their behavior varies across user categories and content domains and how these differences influence content popularity are rarely addressed. From a novel view of seven content domains, a detailed picture of the behavior variations among five user groups, from the views of both the elites and mass, is drawn on Weibo, one of the most popular Twitter-like services in China. Interestingly, elites post more diverse content with video links, while the mass possess retweeters of higher loyalty. According to these variations, user-oriented actions for enhancing content popularity are discussed and testified. The most surprising finding is that the diverse content does not always bring more retweets, and the mass and elites should promote content popularity by increasing their retweeter counts and loyalty, respectively. For the first time, our results demonstrate the possibility of highly individualized strategies of popularity promotions in social media, instead of a universal principle.
Preventable Burns from Domestic Tap Water
Authors: Prokopenko Max , Reed Alistair J. M. , Chicco Maria , Issa Fadi
Published: May 2022

Tap water scalds from domestic outlets can afflict large body surface areas. Such injuries are preventable and carry significant associated morbidity, mortality, and economic burden. Previously identified risk factors include age (<5 or >65 years old) and the presence of physical or mental disabilities. Education campaigns and advances in legislation mandating the restriction of tap water temperature at user outlets have been employed in an attempt to prevent such injuries. Nonetheless, the incidence of these injuries persists, and further mitigating measures must be implemented to minimize their occurrence. The purpose of this study was to determine the groups at risk for such injuries and whether this has recently changed. A retrospective observational study was carried out to include patients admitted with tap water scalds to a regional burn’s unit from October 2016 to September 2020. Twenty-three patients were included, and their incidence was 5.75 cases per year, equating to 5.1% of all scalds requiring inpatient treatment. The very young (<5 years old) and elderly (>65 years old) accounted for the majority of admissions (65.2%), 26.1% had a mental disability, and 30.4% had a physical disability. Tap water scalds continue to cause preventable injuries affecting all ages, and in particular, the elderly and patients with pre-existing disabilities.
Numerical Study on Characteristics of Bedrock and Surface Failure in Mining of Shallow-Buried MCS
Authors: Liu Guangchun , Zhang Wenzhi , Zou Youfeng , Chai Huabin , Xue Yongan
Published: May 2022

Coal is one of the important energy sources for industry. When it is mined, it will cause the destruction of bedrock and surface. However, it is more severe in mining shallow-buried multi coal seams (SBMCS). To better reveal the characteristics of the bedrock and surface damage, we have carried out a theoretical analysis, as well as used numerical simulations and field monitoring methods to study the surface and bedrock damage caused by the mining of SBMCS. The characteristics of bedrock and surface failure structure, settlement, and stress distribution were studied and analyzed. The findings show that the collapsed block, formed by the rupture of the overlying stratum, interacts with the surrounding rock to form large cavities and gaps, and the stress concentration occurs between them. The maximum downward vertical concentration stress is about 9.79 MPa. The mining of the lower coal seam can lead to repeated failure of the upper bedrock and goaf. The settlement of bedrock presents gradient change, and the settlement of upper bedrock is large, about 8.0 m, and the maximum settlement is 8.183 m, while that of lower bedrock is small and about 3.5–4.0 m. The weak rock stratum in the bedrock is crushed by the change stress of repeated mining, and formed a broken rock stratum. The cracks in the bedrock develop directly to the ground. On the ground, tensile cracks, compression uplift, stepped cracks, and even collapse pits are easy to cause in mining SBMCS. Affected by repeated mining, the variation of surface vertical stress is complex and disorderly in the middle of the basin, and the variation of horizontal stress is mainly concentrated on the edge of the basin. The maximum stress reaches 100 KPa, and the minimum stress is about 78 KPa. Through theoretical analysis and discussion, the size of the key blocks is directly related to the thickness and strength of the rock stratum.
Do Nuclear Energy, Renewable Energy, and Environmental-Related Technologies Asymmetrically Reduce Ecological Footprint? Evidence from Pakistan
Authors: Usman Muhammad , Jahanger Atif , Radulescu Magdalena , Balsalobre-Lorente Daniel
Published: May 2022

Can Pakistan’s environmental-related technologies (ERT) and nuclear and renewable energy mitigate environmental pollution? As global warming and climate change rise dramatically, economies shift to friendly energy substitutions and eco-friendly technologies, contributing to the mitigation of environmental contamination. In this scenario, policy and academic analysts have paid more concentration to renewable and nuclear energy deployment with ERT installation. To achieve this goal, the present study scrutinizes the asymmetric effects of nuclear energy, renewable energy, and ERT on the ecological footprint of Pakistan. The current research applies a novel non-linear autoregressive distributive lag method from 1991 to 2020. The results of the current analysis show that negative changes in nuclear energy increase emissions levels in the long run, while positive and negative changes in renewable energy deployment significantly overcome the burden on the environment. Similarly, positive and negative changes in ERT reduce pollution levels in the long run. Moreover, these long-run outcomes are analogous to short-run findings for Pakistan. Therefore, there is a dire requirement to increase the consumption of renewable and nuclear energy sources and take advantage of the noteworthy impact of an uncontaminated atmosphere through clean ERT potentials.
A Three-Dimensional Finite-Element Model in ABAQUS to Analyze Wellbore Instability and Determine Mud Weight Window
Authors: Bozorgi Mohammad Javad , Parham Masoud , Rahmani Omeid , Piroozian Ali , Gebretsadik Haylay Tsegab , Ibad Syed Muhammad
Published: May 2022

Wellbore instability is one of the main problems of the oil industry, causing high costs in the drilling operation. Knowing about the mechanical properties of involved formations and in-situ stresses is a privilege gained by determining an appropriate mud weight window (MWW). To this aim, a three-dimensional (3D) finite-element model was simulated in ABAQUS to analyze in-situ stresses and determine the MWW in the drilling operation of wellbore-D in the Azar oilfield. The results from the 3D finite model revealed that the Azar oilfield is structurally under the impact of a complex tectonic system dominated by two reverse faults with a configuration of σH > σh > σv across the Sarvak Formation. The amount of vertical, minimum, and maximum horizontal stresses was 90.15, 90.15, and 94.66 MPa, respectively, at a depth of 4 km. Besides, the amount of pore pressure and its gradient was 46 MPa and 11.5 MPa/km, respectively. From drilling wellbore-D in the direction of the maximum horizontal stress, the lower limit of the MWW was obtained at 89 pcf. In this case, the results showed that the wellbore with a deviation angle of 10° is critical with a mud weight lower than 89 pcf. It caused the fall of the wellbore wall within the plastic zone sooner than other deviation angles. Also, in the case of drilling wellbore in the direction of minimum horizontal stress, the lower limit of the MWW was 90.3 pcf. Moreover, in the deviation angle of approximately 90°, the wellbore wall remained critical while the mud weight was below 90.3 pcf. Comparison of the results of numerical and analytical modeling showed that the modeling error falls within an acceptable value of < 4%. As a result, the wellbore with the azimuth of the maximum horizontal stress needed less mud weight and decreased the drilling costs. This particular research finding also provides insights for obtaining the lower limit of the mud weight window and determining the optimal path of the well-bore when using directional drilling technology.
A Comprehensive Survey of Alkaline Electrolyzer Modeling: Electrical Domain and Specific Electrolyte Conductivity
Authors: Gambou Frank , Guilbert Damien , Zasadzinski Michel , Rafaralahy Hugues
Published: May 2022

Alkaline electrolyzers are the most widespread technology due to their maturity, low cost, and large capacity in generating hydrogen. However, compared to proton exchange membrane (PEM) electrolyzers, they request the use of potassium hydroxide (KOH) or sodium hydroxide (NaOH) since the electrolyte relies on a liquid solution. For this reason, the performances of alkaline electrolyzers are governed by the electrolyte concentration and operating temperature. Due to the growing development of the water electrolysis process based on alkaline electrolyzers to generate green hydrogen from renewable energy sources, the main purpose of this paper is to carry out a comprehensive survey on alkaline electrolyzers, and more specifically about their electrical domain and specific electrolytic conductivity. Besides, this survey will allow emphasizing the remaining key issues from the modeling point of view.
Three-Phase Unbalance Improvement for Distribution Systems Based on the Particle Swarm Current Injection Algorithm
Authors: Chang Chien-Kuo , Cheng Shih-Tang , Boyanapalli Bharath-Kumar
Published: May 2022

The aim of this study is to improve the three-phase unbalanced voltage at the secondary side of a distribution transformer. The proposed method involves compensation sources injecting three different single-phase currents into the connected point of a grid. The computations of optimal single-phase currents are performed using the circuit analysis method and particle swarm optimization algorithm. An unbalanced three-phase power distribution system model is constructed, including a transformer Δ–Δ connection, V–V connection, load balance, load unbalance combination, and three single-phase compensation current sources. The results show that the voltage unbalance rate of the electricity user side is improved to less than 1%, and the three-phase total compensation apparent power is approximately 0 VA. In the future, the application of the model as an auxiliary service could be achieved by adding an energy storage system.
Evaluation of Various Tree-Based Ensemble Models for Estimating Solar Energy Resource Potential in Different Climatic Zones of China
Authors: Zhou Zhigao , Lin Aiwen , He Lijie , Wang Lunche
Published: May 2022

Solar photovoltaic (PV) electricity generation is growing rapidly in China. Accurate estimation of solar energy resource potential (Rs) is crucial for siting, designing, evaluating and optimizing PV systems. Seven types of tree-based ensemble models, including classification and regression trees (CART), extremely randomized trees (ET), random forest (RF), gradient boosting decision tree (GBDT), extreme gradient boosting (XGBoost), gradient boosting with categorical features support (CatBoost) and light gradient boosting method (LightGBM), as well as the multi-layer perceotron (MLP) and support vector machine (SVM), were applied to estimate Rs using a k-fold cross-validation method. The three newly developed models (CatBoost, LighGBM, XGBoost) and GBDT model generally outperformed the other five models with satisfactory accuracy (R2 ranging from 0.893–0.916, RMSE ranging from 1.943–2.195 MJm−2d−1, and MAE ranging from 1.457–1.646 MJm−2d−1 on average) and provided acceptable model stability (increasing the percentage in testing RMSE over training RMSE from 8.3% to 31.9%) under seven input combinations. In addition, the CatBoost (12.3 s), LightGBM (13.9 s), XGBoost (20.5 s) and GBDT (16.8 s) exhibited satisfactory computational efficiency compared with the MLP (132.1 s) and SVM (256.8 s). Comprehensively considering the model accuracy, stability and computational time, the newly developed tree-based models (CatBoost, LighGBM, XGBoost) and commonly used GBDT model were recommended for modeling Rs in contrasting climates of China and possibly similar climatic zones elsewhere around the world. This study evaluated three newly developed tree-based ensemble models of estimating Rs in various climates of China, from model accuracy, model stability and computational efficiency, which provides a new look at indicators of evaluating machine learning methods.
A Fault-Line Selection Method for Small-Current Grounded System Based on Deep Transfer Learning
Authors: Su Xianxin , Wei Hua
Published: May 2022

Usually, data-driven methods require many samples and need to train a specific model for each substation instance. As different substation instances have similar fault features, the number of samples required for model training can be significantly reduced if these features are transferred to the substation instances that lack samples. This paper proposes a fault-line selection (FLS) method based on deep transfer learning for small-current grounded systems to solve the problems of unstable training and low FLS accuracy of data-driven methods in small-sample cases. For this purpose, fine-turning and historical averaging techniques are proposed for use in transfer learning to extract similar fault features from other substation instances and transfer these features to target substation instances that lack samples to improve the accuracy and stability of the model. The results show that the proposed method obtains a much higher FLS accuracy than other methods in small-sample cases; it has a strong generalization ability, low misclassification rate, and excellent application value.
Thermal Stability and Thermodynamic Performances of Pure Siloxanes and Their Mixtures in Organic Rankine Cycles
Authors: Di Marcoberardino Gioele , Invernizzi Costante Mario , Iora Paolo , Arosio Luca , Canavese Marcello , Lunghi Angelo , Mazzei Antonella
Published: May 2022

Organic Rankine cycles are often the best solution for the conversion of thermal energy. The many working fluids include silicon oils. One crucial issue that determines the choice of a working fluid is its thermochemical stability, as this sets a limit to the maximum temperature at which the fluid can be used in a power plant. A second subject, much debated today, is the use of mixtures in ORCs. In the first part of this study, an investigation into the thermal stability of siloxanes using two different approaches was carried out. The results confirmed a limit working temperature for the considered siloxanes of about 300 °C, with a degradation that advanced significantly over time at 350 °C. In the second part of the study, an analysis of the thermodynamic performances of some siloxane mixtures was carried out. It was found that the efficiencies of the corresponding thermodynamic cycles were substantially the same as for the pure fluids used today. By changing the composition of the mixture, it was also possible to vary, within reasonable limits, the values of the condensation pressure, adapting the thermodynamic cycle to the different situations that can be encountered in current practice.
The Historical Complexity of Tree Height Growth Dynamic Associated with Climate Change in Western North America
Authors: Messaoud Yassine , Reid Anya , Tchebakova Nadezhda M. , Goldman Jack A. , Hofgaard Annika
Published: May 2022

The effect of climate on tree growth has received increased interest in the context of climate change. However, most studies have been limited geographically and with respect to species. Here, sixteen tree species of western North America were used to investigate the response of trees to climate change. Forest inventory data from 36,944 stands established between 1600 and 1968 throughout western North America were summarized. The height growth (top height at a breast-height age of 50 years) of healthy dominant and co-dominant trees was related to annual and summer temperatures, the annual and summer Palmer Drought Severity Indexes (PDSIs), and the tree establishment date (ED). Climate-induced height growth patterns were then tested to determine links to the spatial environment (geographic locations and soil properties), the species’ range (coastal, interior, or both), and traits (shade tolerance and leaf form). Analysis was performed using a linear mixed model (total species) and a general linear model (species scale). Climate change was globally beneficial, except for Alaska yellow-cedar (Chamaecyparis nootkatensis (D. Don) Spach), and growth patterns were magnified for coastal-ranged, high-shade-tolerant, and broadleaf species, and mostly at the northernmost extents of these species’ ranges. Nevertheless, growth patterns were more complex with respect to soil properties. A growth decline for some species was observed at higher latitudes and elevations and was possibly related to increased cloudiness, precipitation, or drought (in interior areas). These results highlight the spatio-temporal complexity of the growth response to recent global climate change.
Pinus tabulaeformis Forests Have Higher Carbon Sequestration Potential Than Larix principis-rupprechtii Forests in a Dryland Mountain Ecosystem, Northwest China
Authors: Han Chun , Li Yage , Dong Xiaoxue , Zhao Changming , An Lizhe
Published: May 2022

Carbon sinks in terrestrial ecosystems can be significantly increased by afforestation, which will slow global warming. However, it is still unclear how different plantations influence the carbon sink and how they respond to environmental factors, especially in drylands. In this study, eddy correlation method (EC) was used to measure carbon and water fluxes and environmental factors of two artificial forests (Larix principis-rupprechtii and Pinus tabulaeformis) in the dryland of Northwest China, and the responses of evapotranspiration (ET), net ecosystem exchange (NEE), gross primary productivity (GPP), and ecosystem respiration (RECO) to environmental factors were also assessed. Results showed that the L. principis-rupprechtii forest ecosystem had higher water use efficiency (WUE), light use efficiency (LUE), GPP, and RECO than the P. tabulaeformis forest ecosystem. However, the proportion of net ecosystem production (NEP) to GPP in the P. tabulaeformis forest ecosystem (62.89%) was higher than that in the L. principis-rupprechtii forest ecosystem (47.49%), indicating that the P. tabulaeformis forest ecosystem had the higher carbon sequestration efficiency. In addition, the CO2 and H2O fluxes in the L. principis-rupprechtii forest ecosystem were more sensitive to environmental factors, compared with the P. tabulaeformis forest ecosystem. Further, the RECO of the L. principis-rupprechtii forest ecosystem was more sensitive to temperature changes, which implies that the L. principis-rupprechtii forest ecosystem will release more CO2 than the P. tabulaeformis forest ecosystem with a warming climate. Therefore, the P. tabulaeformis forest ecosystem may have better carbon sequestration potential. These results are important for understanding the effects of climate change on the CO2 and H2O cycles in coniferous plantation ecosystems in drylands.
Security in Wireless Sensor Networks: A Cryptography Performance Analysis at MAC Layer
Authors: Tropea Mauro , Spina Mattia Giovanni , De Rango Floriano , Gentile Antonio Francesco
Published: May 2022

Wireless Sensor Networks (WSNs) are networks of small devices with limited resources which are able to collect different information for a variety of purposes. Energy and security play a key role in these networks and MAC aspects are fundamental in their management. The classical security approaches are not suitable in WSNs given the limited resources of the nodes, which subsequently require lightweight cryptography mechanisms in order to achieve high security levels. In this paper, a security analysis is provided comparing BMAC and LMAC protocols, in order to determine, using AES, RSA, and elliptic curve techniques, the protocol with the best trade-off in terms of received packets and energy consumption.
Third Hankel Determinant for the Logarithmic Coefficients of Starlike Functions Associated with Sine Function
Authors: Khan Bilal , Aldawish Ibtisam , Araci Serkan , Khan Muhammad Ghaffar
Published: May 2022

The logarithmic functions have been used in a verity of areas of mathematics and other sciences. As far as we know, no one has used the coefficients of logarithmic functions to determine the bounds for the third Hankel determinant. In our present investigation, we first study some well-known classes of starlike functions and then determine the third Hankel determinant bound for the logarithmic coefficients of certain subclasses of starlike functions that also involve the sine functions. We also obtain a number of coefficient estimates. Some of our results are shown to be sharp.
Risk Management Assessment in Oil and Gas Construction Projects Using Structural Equation Modeling (PLS-SEM)
Authors: Kassem Mukhtar A.
Published: May 2022

Oil and gas construction projects are of great importance to support and facilitate the process of operation and production. However, these projects usually face chronic risks that lead to time overrun, cost overrun, and poor quality, affecting the projects’ success. Hence, this study focused on identifying, classifying, and modeling the risk factors that have negative effects on the success of construction projects in Yemen. The data were collected through a structured questionnaire. Statistical analysis, relative important index method, and probability impact matrix analysis were carried out to classify and rank the risk factors. The partial least squares path modeling or partial least squares structural equation modeling (PLS-PM, PLS-SEM) is a method for structural equation modeling that allows an estimation of complex cause–effect relationships in path models with latent variables. PLS-SEM was employed to analyze data collected from a questionnaire survey of 314 participants comprising the clients, contractors, and consultants working in oil and gas construction projects. The results showed that the goodness of fit index of the model is 0.638. The developed model was deemed to fit because the analysis result of the coefficient of determination test (R2) of the model was 0.720, which indicates the significant explanation of the developed model for the relationship between the causes of risks and their effects on the success of projects. The most impacted internal risk categories include project management, feasibility study design, and resource material availability. The main external risk elements include political, economic, and security considerations. The created risk factor model explained the influence of risk factors on the success of construction projects effectively, according to statistical and expert validation tests.
Tragacanth Gum Hydrogel-Derived Trimetallic Nanoparticles Supported on Porous Carbon Catalyst for Urea Electrooxidation
Authors: Thamer Badr M. , Moydeen Abdulhameed Meera , El-Newehy Mohamed H.
Published: May 2022

The fabrication of electrocatalysts with high catalytic activity, high durability and low cost towards urea oxidation by a facile method is a great challenge. In this study, non-precious NiCoFe trimetallic supported on porous carbon (NiCoFe@PC) was prepared via gelation and pyrolysis method, presenting a remarkable electrocatalytic activity with low onset potential for urea oxidation in an alkaline medium. Field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) were used to clarify the morphology of the NiCoFe@PC nanostructure and its nanoparticle size of 17.77 nm. The prepared catalyst with the composition ratio of 24.67, 5.92 and 5.11% for Ni, Fe and Co, respectively, with highly crystalline nanoparticles, fixed on porous carbon, according to energy-dispersive X-ray (EDX) and X-ray diffraction (XRD) analysis. The FeCoNi@PC catalyst showed a catalytic activity of 44.65 mA/cm2 at 0.57 V vs. Ag/AgCl and a low onset potential of 218 mV, which is superior to many other transition bi/trimetallic-based catalysts previously reported.
Decellularized Periosteum-Derived Hydrogels Promote the Proliferation, Migration and Osteogenic Differentiation of Human Umbilical Cord Mesenchymal Stem Cells
Authors: Li Shuyi , Deng Rongli , Forouzanfar Tim , Wu Gang , Quan Daping , Zhou Miao
Published: May 2022

Human umbilical cord mesenchymal stem cells (hUCMSCs) are promising for bone tissue engineering, which have a non-invasive harvesting process, high cell yield, favorable proliferation capacity, and low immunogenicity. However, the osteogenic efficacy of hUCMSCs is relatively lower than that of bone marrow mesenchymal stem cells (BMSCs). Hydrogels from decellularized extracellular matrix (dECM) preserve the biological compositions and functions of natural ECM, which can provide tissue-specific cues to regulate phenotypic expression and cell fate. It is unknown, however, whether hydrogels from periosteum can serve as pro-osteogenic carriers of hUCMSCs. Herein, a decellularized periosteum-derived hydrogel (dPH) was fabricated to reveal the effects of periosteum-specific cues on the bioactivities of hUCMSCs. A widely used non-bone/periosteum-derived ECM hydrogel product, Matrigel, was used as the control group. After decellularization, the absence of nuclei in the histological analysis indicated a successful removal of cellular components, which was also confirmed by DNA content quantification. The storage modulus of dPH increased (from 164.49 ± 29.92 Pa to 855.20 ± 20.67 Pa) with increasing concentration (from 0.5% to 1%). With a highly porous, fibrous microstructure, dPH had a more hydrophilic surface than Matrigel, of which the water contact angle reduced 62.62 ± 0.04%. Furthermore, dPH prominently promoted the initial cellular spreading with a significantly higher cell surface area (1.47-fold), cell spreading length (1.45-fold) and proliferation (approximately 1.05–1.13-fold) of hUCMSCs than those of Matrigel. Additionally, dPH was conducive to cell migration, whereas no cells migrated to Matrigel in the Transwell model. Compared with those of the Matrigel group, the osteogenesis-related genes expression levels (runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), osteopontin (OPN), and osteocalcin (OCN)) and mineralized matrix formation (9.74-fold) of the hUCMSCs significantly increased in the dPH group. Our study indicated that dPH could provide a pro-osteogenic microenvironment for hUCMSCs, thereby revealing a promising application potential to repair bone defects.
Thermal Insulation Performance of Silica Aerogel Composites Doped with Hollow Opacifiers: Theoretical Approach
Authors: Liu He , Liu Jia’ao , Tian You , Jiao Junhua , Wu Xuehong
Published: May 2022

Silica aerogels demonstrate great promise in thermal insulation applications, such as energy-efficient buildings, cold-chain transportation, and aerospace engineering. However, the application of pure silica aerogels is limited in high temperature applications (>500 K) due to their transparency in the wavelength of 2–8 µm. The conventional strategy is to dope silica aerogel with solid spherical opacifiers (e.g., SiC, TiO2, and ZrO2) to increase their extinction coefficient; however, incorporating solid opacifiers into silica aerogel matrix improves the structural density of silica aerogel composites. Herein, we propose to improve the extinction coefficient of the silica aerogel by using hollow opacifiers. A theoretical model was developed to investigate the parameters including the outer diameter, shell thickness, and mass fraction on both the radiative thermal conductivity and total thermal conductivity of the silica aerogel composite doped with hollow opacifiers. Our results indicate that doping hollow opacifiers can enable the silica aerogel matrix to achieve lower radiative thermal conductivity when compared to matrices doped with optimally sized solid opacifiers. The total thermal conductivity of silica aerogel doped with hollow opacifiers could be lower than that of the silica aerogel doped with optimally sized solid opacifiers. This work contributes to the understanding of heat transfer within porous materials and guides the structural design of high-temperature thermally insulating materials.
XCMAX4: A Robust X Chromosomal Genetic Association Test Accounting for Covariates
Authors: Su Youpeng , Hu Jing , Yin Ping , Jiang Hongwei , Chen Siyi , Dai Mengyi , Chen Ziwei , Wang Peng
Published: May 2022

Although the X chromosome accounts for about 5% of the human genes, it is routinely excluded from genome-wide association studies probably due to its unique structure and complex biological patterns. While some statistical methods have been proposed for testing the association between X chromosomal markers and diseases, very a few of them can adjust for covariates. Unfortunately, those methods that can incorporate covariates either need to specify an X chromosome inactivation model or require the permutation procedure to compute the p value. In this article, we proposed a novel analytic approach based on logistic regression that allows for covariates and does not need to specify the underlying X chromosome inactivation pattern. Simulation studies showed that our proposed method controls the size well and has robust performance in power across various practical scenarios. We applied the proposed method to analyze Graves’ disease data to show its usefulness in practice.
The Use of DArTseq Technology to Identify New SNP and SilicoDArT Markers Related to the Yield-Related Traits Components in Maize
Authors: Tomkowiak Agnieszka , Nowak Bartosz , Sobiech Aleksandra , Bocianowski Jan , Wolko Łukasz , Spychała Julia
Published: May 2022

In the last decade, many scientists have used molecular biology methods in their research to locate the grain-yield-determining loci and yield structure characteristics in maize. Large-scale molecular analyses in maize do not only focus on the identification of new markers and quantitative trait locus (QTL) regions. DNA analysis in the selection of parental components for heterotic crosses is a very important tool for breeders. The aim of this research was to identify and select new markers for maize (SNP and SilicoDArT) linked to genes influencing the size of the yield components in maize. The plant material used for the research was 186 inbred maize lines. The field experiment was established in twolocations. The yield and six yield components were analyzed. For identification of SNP and SilicoDArT markers related to the yield and yield components, next-generation sequencing was used. As a result of the biometric measurements analysis, differentiation in the average elevation of the analyzed traits for the lines in both locations was found. The above-mentioned results indicate the existence of genotype–environment interactions. The analysis of variance for the observed quality between genotypes indicated a statistically significant differentiation between genotypes and a statistically significant differentiation for all the observed properties betweenlocations. A canonical variable analysis was applied to present a multi-trait assessment of the similarity of the tested maize genotypes in a lower number of dimensions with the lowest possible loss of information. No grouping of lines due to the analyzed was observed. As a result of next-generation sequencing, the molecular markers SilicoDArT (53,031) and SNP (28,571) were obtained. The genetic distance between the analyzed lines was estimated on the basis of these markers. Out of 81,602 identified SilicoDArT and SNP markers, 15,409 (1559 SilicoDArT and 13,850 SNPs) significantly related to the analyzed yield components were selected as a result of association mapping. The greatest numbers of molecular markers were associated with cob length (1203), cob diameter (1759), core length (1201) and core diameter (2326). From 15,409 markers significantly related to the analyzed traits of the yield components, 18 DArT markers were selected, which were significant for the same four traits (cob length, cob diameter, core length, core diameter) in both Kobierzyce and Smolice. These markers were used for physical mapping. As a result of the analyses, it was found that 6 out of 18 (1818; 14,506; 2317; 3233; 11,657; 12,812) identified markers are located inside genes. These markers are located on chromosomes 8, 9, 7, 3, 5, and 1, respectively.
Impact of Statewide Mandatory Medicaid Managed Care (SMMC) Programs on Hospital Obstetric Outcomes
Authors: Symum Hasan , Zayas-Castro José
Published: May 2022

The state of Florida implemented mandatory managed care for Medicaid enrollees via the Statewide Medicaid Managed Care (SMMC) program in April of 2014. The objective of this study was to examine the impact of the implementation of the SMMC program on the access to care and quality of maternal care for Medicaid enrollees, as measured by several hospital obstetric outcomes. The primary data source for this retrospective observational study was the Hospital Cost and Utilization Project (HCUP) all-payer State ED (SED) visit and State Inpatient Databases (SIDs) from 2010 to 2017. The primary health outcomes for obstetric care were primary cesarean, preterm birth, postpartum preventable ED visits, postpartum preventable readmissions, and vaginal delivery after cesarean (VBAC) rates. Using difference-in-differences (DID) estimation, selected health outcomes were examined for Florida residents with Medicaid beneficiaries (treatment) and the commercially insured population (comparison), before and after the implementation of SMMC. Improvement in disparities for racial/ethnic minority Medicaid enrollees was estimated relative to whites, compared to the relative change among commercially insured patients. From the DID estimation, the findings showed that SMMC is statistically significantly associated with a higher reduction in primary cesarean rates, preterm births, preventable postpartum ED visits, and readmissions among Medicaid beneficiaries relative to their commercially insured counterparts. However, this study did not find any significant reduction in racial/ethnic disparities in obstetric outcomes. In general, this study highlights the impact of SMMC implementation on obstetric outcomes in Florida and provides important insights and potential scope for improvement in obstetric care quality and associated racial/ethnic disparities.
Quality of Life in Women over 65 Years of Age Diagnosed with Osteoporosis
Authors: Pastor-Robles María Belén , Mayo-Íscar Agustín , Cárdaba-García Rosa M. , Niño-Martín Virtudes
Published: May 2022

(1) Background: Today’s society is moving towards active aging, underlining the importance of understanding and improving quality of life (QoL). This QoL in women over the age of 65 years diagnosed with osteoporosis was compared with the QoL of the general population, and risk factors for osteoporosis related to QoL were identified. (2) Methods: This is an observational, descriptive, cross-sectional study with a personal interview. The study population was 704 women over 65 years of age diagnosed with osteoporosis as of 1 November 2018, based on medical records from four health centers of the eastern Valladolid urban health area. This was a random sample of 247 women stratified by health center. Information on osteoporosis risk factors, comorbidities, daily lifestyle habits, and QoL assessed with the EQ-5D was collected. QoL was modeled using sociodemographic variables, lifestyle, and clinical variables. (3) Results: Women with osteoporosis had a positive perception of their health (EQ-5D% VAS 64.9 ± 18.31). High EQ-5D QoL scores were obtained on the dimensions of mobility: 51.6% [95% CI (44.2%, 58.9%)]; self-care: 75.3% [95% CI (68.5%, 81.2%)]; activities of daily living: 71.4% [95% CI (64.4%, 77.6%)]; pain/discomfort: 25.8% [95% CI (19.8%, 32.6%)]; and anxiety/depression: 53.8% [95% CI (46.4%, 61.0%)]. (4) Conclusions: The QoL of the study group was no worse than the QoL of the general population, except for pain/discomfort and anxiety/depression. Age, highest educational level reached, inflammatory diseases, physical activity, and insomnia were independent predictors of QoL in women with osteoporosis.
The Benefits of Utilizing Total Body Composition as a Predictor of Cardiorespiratory Fitness Based on Age: A Pilot Study
Authors: Heileson Jeffery L. , Papadakis Zacharias , Ismaeel Ahmed , Richardson Kathleen A. , Torres Ricardo , Funderburk LesLee , Gallucci Andrew , Koutakis Panagiotis , Forsse Jeffrey S.
Published: May 2022

Maximal oxygen consumption (VO2max) has been associated with body fat percentage (%BF) or fat free mass. However, most analyses do not consider total body composition (TBC) as defined by %BF, fat free mass index (FFMI—a height-adjusted measure of muscle mass), visceral adipose tissue, and bone mineral content (BMC). The aim of this study was to determine if TBC predicts cardiorespiratory fitness in healthy adults and if a relationship exists in young and older adults. Sixty healthy individuals (age group 1 (AG1, ≤35 years), n = 35; age group 2 (AG2, >35 years), n = 25) were screened in a cross-sectional study and retrospectively examined. All participants completed a full body DEXA scan and a standardized multistage treadmill test to determine VO2max. A multiple linear regression analysis was performed to examine the relationship between TBC and VO2max. The multiple regression model showed an overall significant effect for TBC (p < 0.001, R2 = 0.282). When analyzed by age group, the regression model of TBC was not significant in young adults (AG1, p = 0.319, R2 = 0.141), but significant in older adults (AG2, p < 0.001, R2 = 0.683). Significant predictors of VO2max in the older cohort were %BF (β = −0.748, p = 0.001) and BMC (β = 0.014, p = 0.002). Total body composition predicted VO2max in a small cohort of healthy adults. This study highlights the importance of TBC for cardiovascular health, especially in mid-to later-life individuals.