bluuebunny/crossref_metadata_2025 huggingface dataset:
Platform Service Designs: A Comparative Case Analysis of Technology Features, Affordances, and Constraints for Ridesharing
Authors: Bhappu Anita D. , Lempiälä Tea , Yeo M. Lisa
Published: June 2022

Ridesharing platforms have gained a strong foothold as an alternative transportation option to vehicle ownership for consumers while being contested for causing widespread market disruption. They continue to foster business model innovation and unveil new opportunities for delivering goods and services within the broader sharing economy. However, relatively little is known about the comparative value of services provided by the numerous ridesharing platforms available today. We, therefore, analyze three exemplars within the broader sharing economy: Uber®, BlaBlaCar®, and Zimride®. We find that these ridesharing platforms are unique service systems with different designs for facilitating peer-to-peer service interactions, which are reflected in their technology features, affordances, and constraints. Our analysis offers researchers and platform owners new ways to conceptualize and understand these two-sided, digital markets with a range of participants, user goals, and service experiences. In particular, we demonstrate that platforms can be designed to cultivate entrepreneur dependency or enable prosumer communication and collaborative consumption. Given pending legislation to regulate platform-based work, platform owners should be mindful about creating an asymmetrical power imbalance with providers given assumptions about service interactions and technology features. Furthermore, researchers should account for service design differences, as well as the technology affordances and constraints, of platforms.
Subjective Trusts for the Control of Mobile Robots under Uncertainty
Authors: Kagan Eugene , Rybalov Alexander
Published: June 2022

The paper deals with the methods of handling imperfect information and the control of mobile robots acting under uncertainty. It is assumed that the robots act in autonomous regime and are controlled internally without referring the externally defined probabilities of the states and actions. To control the activity of the robots, we suggest the novel multi-valued logic techniques based on the recently developed measures, known as the subjective trusts. In addition to specification of the robots’ movements, such a technique allows for direct definition of the robots’ swarming using the methods of artificial neural networks with mobile neurons. The suggested methods are verified by numerical simulations and running examples. The resulting framework forms a basis for processing non-probabilistic uncertainties and making individual decisions with imperfect information.
A Compact CSRR-Based Sensor for Characterization of the Complex Permittivity of Dielectric Materials
Authors: Nogueira Jurgen K. A. , Oliveira João G. D. , Paiva Samuel B. , Neto Valdemir P. Silva , D’Assunção Adaildo G.
Published: June 2022

A sensor is proposed to characterize the complex permittivity of dielectric materials in a non-destructive and non-invasive way. The proposed sensor is based on a rectangular patch microstrip two-port circuit with a complementary split-ring resonator (CSRR) element. The slotted CSRR element of the sensor plays a key role in determining the electrical properties of the materials under test (MUT). The sensitivity analysis is determined by varying the permittivity of the MUT. The proposed sensor is simulated and analyzed using Ansoft HFSS software. A prototype was fabricated and measurements were made on two different samples of dielectric materials with complex permittivity values available in the literature. The simulated and measured results showed good agreement.
Active Disturbance Rejection Adaptive Control for Hydraulic Lifting Systems with Valve Dead-Zone
Authors: Yang Fengbo , Zhou Hongping , Deng Wenxiang
Published: June 2022

In this article, the motion control problem of hydraulic lifting systems subject to parametric uncertainties, unmodeled disturbances, and a valve dead-zone is studied. To surmount the problem, an active disturbance rejection adaptive controller was developed for hydraulic lifting systems. Firstly, the dynamics, including both mechanical dynamics and hydraulic actuator dynamics with a valve dead-zone of the hydraulic lifting system, were modeled. Then, by adopting the system model and a backstepping technique, a composite parameter adaptation law and extended state disturbance observer were successfully combined, which were employed to dispose of the parametric uncertainties and unmodeled disturbances, respectively. This much decreased the learning burden of the extended state disturbance observer, and the high-gain feedback issue could be shunned. An ultimately bounded tracking performance can be assured with the developed control method based on the Lyapunov theory. A simulation example of a hydraulic lifting system was carried out to demonstrate the validity of the proposed controller.
Study on Co-Estimation of SoC and SoH for Second-Use Lithium-Ion Power Batteries
Authors: Jiang Nan , Pang Hui
Published: June 2022

Lithium-ion batteries are an ideal power supplier for electric vehicles (EVs) due to their high-power density and wide operating voltage, but their performance decays to 80% before retirement from EVs. Nevertheless, they still have a particular use value after decommissioning, so recycling the retired power battery in cascade can be considered. Therefore, accurate estimation of battery state-of-charge (SoC) and state-of-health (SoH) is crucial for extending the service life and echelon utilization of power lithium-ion battery packs. This paper proposes a comprehensive co-estimation scheme of battery SoC/SoH for the second-use of lithium-ion power batteries in EVs under different cycles using an adaptive extended Kalman filter (AEKF). First, according to the collected battery test data at different aging cycle levels, the external battery characteristics are analyzed, and then a cycle-dependent equivalent circuit model (cECM) is built up. Next, the parameter estimation of this battery model is performed via a recursive least square (RLS) algorithm. Meanwhile, the variations in internal battery parameters of the cycle numbers are fitted and synthesized. Moreover, validation of the estimated parameters is further carried out. Based on this enhanced battery model, the AEKF algorithm is utilized to fulfill battery SoC/SoH estimation simultaneously. The estimated results of SoC/SoH are obtained for a LiCoO2 cell in the case of CCC (constant current condition) under different cycle times. The results show that this proposed co-estimation scheme can predict battery SoC and SoH well, wherein the peak values of the SoC errors are less than 2.2%, and the peak values of SoH, calculated by the estimated capacity and internal resistance, are less than 1.7% and 2.2%, respectively. Hence, this has important guiding significance for realizing the cascade utilization of lithium-ion power batteries.
The Design of a Low Noise and Low Power Current Readout Circuit for Sub-pA Current Detection Based on Charge Distribution Model
Authors: Jiang Dahai , Chen Qinan , Li Zheng , Shan Qiang , Wei Zihui , Xiao Jinjin , Huang Shuilong
Published: June 2022

In this article, we proposed an analytical model based on charge distribution for switched-capacitor trans-impedance amplifiers (SCTIAs). The changes in the load state of the amplifier under different operating conditions and the influence of the gain of the operational amplifier (Opamp) on the trans-impedance gain are analyzed to improve the design theory of switched-capacitor trans-impedance amplifiers. According to the conclusion drawn from the analysis, the trans-impedance amplifier (TIA) has been designed by adopting “correlated double sampling technology” and “cross-connection technology” to optimize input-referred noise current, power consumption, and trans-impedance gain. As a result, the trans-impedance gain reaches up to 206 dB, while the bandwidth is 3 kHz. The current readout system achieves an input-referred noise current floor of 2.96 fA/Hz at 1 kHz, and the power consumption of the system is 0.643 mW. The circuit has been simulated with the technology of 0.18 μm, and the layout area is 1000 μm × 500 μm.
Lessons Learnt from Modelling and Simulating the Bottom-Up Power System Restoration Processes
Authors: Benato Roberto , Dambone Sessa Sebastian , Sanniti Francesco
Published: June 2022

This paper aims to present the gained experience in modeling and simulating bottom-up power system restoration processes. In a system with low inertia, such as a restoration path, the Common Information Models for the regulation systems appear to no longer be suitable for the estimation of the frequency behavior, and thus a detailed model must be considered. On the other hand, due to the predominantly inductive behavior of the HV transmission network, the assumption of decoupling the power-frequency behavior to study the restoration stability seems to be licit. All these issues are discussed and justified in the paper by means of the use of different software packages and of the comparison with on-field recordings.
Experimenting with a Battery-Based Mitigation Technique for Coping with Predictable Partial Shading
Authors: Carbone Rosario , Borrello Cosimo
Published: June 2022

In this paper, the authors propose to use batteries to improve the performance of grid-connected photovoltaic plants when their photovoltaic fields are subject to partial shading phenomena. Particular attention is devoted to predictable and repetitive partial shadings, such as those that often appear in urban residential environments. Firstly, battery packs with proper nominal voltage and capacity are connected in parallel to partially shaded photovoltaic submodules. Then, the shaded photovoltaic submodules are properly disconnected and connected to the respective photovoltaic string by using a “battery control unit”, which is operated by taking into account characteristics of the specific partial shading phenomenon to cope with. To demonstrate the effectiveness of the proposed technique, an experimental study is performed to compare the performances of two identical prototypal grid-connected photovoltaic generators subject to identical artificial and repetitive partial shadings. Only one of the photovoltaic generators is equipped with batteries together with their respective battery control unit, while the second one is simply equipped with conventional bypass diodes. The main advantages of the proposed technique are a greatly improved whole power generation together with the elimination of hotspot phenomena.
Comprehensive Performance Evaluation of a Dual-Function Active Solar Thermal Façade System Based on Energy, Economic and Environmental Analysis in China
Authors: Li Rui , Cui Guomin
Published: June 2022

Promoting the development and utilization of solar energy is a practical way to alleviate the energy crisis and achieve the goal of carbon neutrality. Recently, interest has arisen in the dual-functional active solar thermal façade (ASTF) system that produces hot water throughout the whole year and reduces cooling and heating load as a function of the building façade. Here, a mathematical model of the ASTF system is built and validated by the experimental data, and the annual performance of the ASTF system in representative cities in three climate regions is evaluated. The results are that compared with the common solar water system, the ASTF system adds passive energy savings, which accounts for 5.8%, 7.2% and 11.4% of the total primary energy savings of the system for Shanghai, Beijing and Lanzhou. Compared with the traditional wall, the ASTF saves 16.4% and 23.0% of cooling energy consumption and 102.3% and 92.4% of heating energy consumption for Shanghai and Beijing, respectively. Additionally, it saves 74.7% of heating energy consumption for Lanzhou. Lastly, the impact of the design parameters and operation parameters of the system are investigated, respectively. This study demonstrates a viable path to promoting cost-effective active solar thermal façades in different climates, and the results can be beneficial to further research.
Design of a Low-Cost Electrostatic Precipitator to Reduce Particulate Matter Emissions from Small Heat Sources
Authors: Drga Juraj , Holubčík Michal , Čajová Kantová Nikola , Červenka Bystrík
Published: June 2022

Capturing particulate matter (PM) is an important issue due to the protection of human health and the quality of their life. This paper describes the innovation of an affordable particulate matter capture device for small heat sources to reduce particulate matter emissions. The design of two investigated variants of the device is based on the principle of a tubular electrostatic precipitator with one charging electrode placed in the chimney. The design of the precipitators is aimed at increasing the area of the collecting electrodes by elements dividing precipitation space, with a simultaneously increased number of charging electrodes. The influence of the elements’ application on the pressure drop and the gas flow velocity through the devices is analyzed by computational fluid dynamics (CFD). The work is further focused on the economic evaluation of precipitators and design adjustments for lower energy consumption. The achieved results show the right direction of efforts to improve the equipment designed to capture PM emissions.
Performance Evaluation of PVT Air Collector Coupled with a Triangular Block in Actual Climate Conditions in Korea
Authors: Choi Hwi-Ung , Choi Kwang-Hwan
Published: June 2022

This study experimentally investigated the performance of a PVT air collector coupled with a triangular block. The triangular block, newly suggested by the authors, is a triangular-shaped obstacle and was inserted at the bottom of the PVT air collector to enhance the heat transfer performance of the collector. The experiment was carried out in actual climate conditions in Korea with two air mass flow rate conditions: 0.03606 kg/m2 s and 0.06948 kg/m2 s. Results show the average values of electrical efficiency of the collector during the test period to be 16.15% and 16.43% for each air mass flow rate, while thermal efficiencies were 28.83% and 38.36%, respectively. The average values of total energy efficiencies were found to be 44.99% and 54.79%, respectively. The results show that air mass flow rate has a large impact on thermal and total energy efficiency, while it has a small impact on electrical efficiency. Furthermore, it was confirmed that the PVT air collector coupled with a triangular block can enhance the utilization of solar energy since the thermal performance was higher than that of the collector without a triangular block.
Effects of Different Exhaust Gas Recirculation (EGR) Rates on Combustion and Emission Characteristics of Biodiesel–Diesel Blended Fuel Based on an Improved Chemical Mechanism
Authors: Huang Huiqiong , Tian Jie , Li Jiangtao , Tan Dongli
Published: June 2022

This paper studies the effects of different exhaust gas recirculation (EGR) rates (0%, 5%, 10%, and 15%) on the combustion, performance, and emission characteristics of a biodiesel–diesel (20% biodiesel + 80% diesel) blended fuel engine. This paper mainly analyzes the effects on engine cylinder temperature, cylinder pressure, brake thermal efficiency (BTE), brake-specific fuel consumption (BSFC), NOx emissions, carbon monoxide (CO) emissions, hydrocarbon (HC) emissions, and soot emissions. Firstly, a 3D-CFD model was established by using CONVERGE software, combined with an improved chemical kinetic mechanism including 98 species and 314 reactions, and the accuracy of the simulation model was verified by experimental results. Secondly, the effects of different EGR rates on the combustion, performance, and emission characteristics of biodiesel–diesel blended fuel were studied. The results showed that with the increase in the EGR rate, the cylinder pressure and cylinder temperature in the cylinder decreased. When the EGR rate was 15%, the maximum cylinder temperature decreased by 4.33%. In addition, BSFC increased and BTE decreased. Moreover, with the increase in the EGR rate, NOx decreased significantly, and the higher the EGR rate, the more obvious the reduction in NOx emissions. When the EGR rate was 15%, NOx was reduced by 78.89%. However, with the increase in the EGR rate, the emissions of soot, HC, and CO increased. The optimal EGR rate for the engine is 10%.
The Role of Resource Consumption Accounting in Achieving Competitive Prices and Sustainable Profitability
Authors: Mustafa Abdurrahman Mawlood , Azimli Asil , Sabir Jaf Rizgar Abdullah
Published: June 2022

This study examines the roles of resource consumption accounting and competitive prices in attaining sustainable profitability. The objectives were (1) to determine whether the adoption of resource consumption accounting practices yields significant improvements in competitive strategies in a highly competitive situation where activity-based costing has proved to be insignificant, and (2) to ascertain if the positive relationship between competitive pricing and sustainable profitability is increased by the extent to which resource consumption accounting exerts pressure for sustainability profitability. A PLS-SEM procedure was applied in analysing 129 of the top 30 performing companies’ structured questionnaire responses drawn from five industries in Kurdistan from 2021. The empirical results demonstrated that competitive pricing models involving resource consumption accounting systems provide superior price forecasting, error reduction and profit maximisation capabilities than existing energy models. The study’s outcomes highlight that the extent to which resource consumption accounting exerts pressure on sustainability profitability significantly increases the positive relationship between competitive pricing and sustainable profitability. The results of this study advance construct and item development involving competitive pricing and resource consumption accounting while testing relationships to uncover the moderating role of resource consumption accounting in profit maximisation. Thus, energy and non-energy industrial companies must rely on resource consumption accounting to set competitive prices and enhance and sustain their profitability by considering the overlooked energy pricing stochastic parameters and errors amid rising energy shortages and costs.
Cooling Thermal Comfort and Efficiency Parameters of Ceiling Panels, Underfloor Cooling, Fan-Assisted Radiators, and Fan Coil
Authors: Võsa Karl-Villem , Ferrantelli Andrea , Kurnitski Jarek
Published: June 2022

Climate change has brought a compelling need for cooling living spaces to the attention of researchers as well as construction professionals. The problem of overheating enclosures is now exacerbated in traditionally affected areas and is also affecting countries that were previously less prone to the issue. In this paper, we address measurements of thermal comfort and cooling emission efficiency parameters for different devices: ceiling panels, underfloor cooling, fan-assisted radiators, and fan coil. These devices were tested in low and high cooling capacities of up to 40 W/m2 while also featuring heating dummies to imitate internal heat gains. Air temperatures were measured at different heights, allowing to evaluate the thermal stratification with high accuracy. Thermal comfort differences of the tested systems were quantified by measuring both air velocities and operative temperatures at points of occupancy. In summary, the best-performing cooling devices for the studied cooling applications were the ceiling panels and fan radiators, followed by underfloor cooling, with a limitation of stratification. Because of the strong jet, fan coil units did not achieve thermal comfort within the whole occupied zone. The results can be utilized in future studies for cooling emission efficiency and energy consumption analyses of the different cooling devices.
Response of Soil Enzyme Activities to Natural Vegetation Restorations and Plantation Schemes in a Landslide-Prone Region
Authors: Guo Donglei , Ou Yansheng , Zhou Xiaohe , Wang Xia , Zhao Yunfei , Li Jia , Xiao Jinjin , Hao Zhiguo , Wang Kaichang
Published: June 2022

Soil enzyme activities in different plantation types and land use patterns could indicate changes in soil quality. This research was aimed at exploring the dynamics of soil enzyme activities involved in carbon, nitrogen and phosphorus cycling, and their responses to changes in soil physicochemical properties resulting from natural vegetation restorations and plantation schemes. Knowing about the effects of soil physicochemical properties on soil enzyme patterns is crucial for understanding ecosystem functions and processes. The study selected four main land-use types (natural forestland, natural grassland, artificial forestland, and artificial grassland) and one control plot (bare land) in the West Qinling Mountains, China, which is a typical landslide region. We collected the soil samples from each land use type and tested their physicochemical properties and enzyme activities compared with control land. The results showed that both natural vegetation restoration and artificial plantation schemes have significant effects on enzyme activities. Soil physicochemical properties explained 92.2% of the variation in soil enzyme activities for natural vegetation restoration, while it only explained 77.8% of the variation in soil enzyme activities for plantation schemes. Furthermore, natural vegetation had a greater effect than the plantation schemes on soil enzyme activities.
Forest Fragmentation and Fires in the Eastern Brazilian Amazon–Maranhão State, Brazil
Authors: Silva-Junior Celso H. L. , Buna Arisson T. M. , Bezerra Denilson S. , Costa Ozeas S. , Santos Adriano L. , Basson Lidielze O. D. , Santos André L. S. , Alvarado Swanni T. , Almeida Catherine T. , Freire Ana T. G. , Rousseau Guillaume X. , Celentano Danielle , Silva Fabricio B. , Pinheiro Maria S. S. , Amaral Silvana , Kampel Milton , Vedovato Laura B. , Anderson Liana O. , Aragão Luiz E. O. C.
Published: June 2022

Tropical forests provide essential environmental services to human well-being. In the world, Brazil has the largest continuous area of these forests. However, in the state of Maranhão, in the eastern Amazon, only 24% of the original forest cover remains. We integrated and analyzed active fires, burned area, land use and land cover, rainfall, and surface temperature datasets to understand forest fragmentation and forest fire dynamics from a remote sensing approach. We found that forest cover in the Maranhão Amazon region had a net reduction of 31,302 km2 between 1985 and 2017, with 63% of losses occurring in forest core areas. Forest edges extent was reduced by 38%, while the size of isolated forest patches increased by 239%. Forest fires impacted, on average, around 1031 ± 695 km2 year−1 of forest edges between 2003 and 2017, the equivalent of 60% of the total burned forest in this period. Our results demonstrated that forest fragmentation is an important factor controlling temporal and spatial variability of forest fires in the eastern Amazon region. Thus, both directly and indirectly, forest fragmentation can compromise biodiversity and carbon stocks in this Amazon region.
Regulating the Physicochemical Properties of Chitosan Films through Concentration and Neutralization
Authors: Xu Jie , Liu Kun , Chang Wei , Chiou Bor-Sen , Chen Maoshen , Liu Fei
Published: June 2022

Chitosan offers real potential for use in food preservation, biomedicine, and environmental applications due to its excellent functional properties, such as ease in the fabrication of large films, biocompatibility, and antibacterial properties. However, the production and application of chitosan films were limited by their strong residual acetic acid taste, weak mechanical properties, and poor water vapor barrier properties. In this study, the effects of the chitosan concentration in the film-forming solutions and the neutralization treatment on the physicochemical properties of chitosan films were examined. The results demonstrated that the chitosan concentration affected the mechanical and barrier properties of chitosan films without the neutralization treatment. This was mainly due to the low acetic acid contents in chitosan films after drying. Acetic acid acted as a plasticizer within chitosan films resulting in a looser network structure. After neutralization, the chitosan films showed improvements in properties, with little effect on the chitosan concentration in the film-forming solutions. Moreover, chitosan films after neutralization showed no residual acetic acid. Therefore, neutralization could effectively improve the performance of chitosan films.
Lacticaseibacillus paracasei as a Modulator of Fatty Acid Compositions and Vitamin D3 in Cream
Authors: Złoch Michał , Rafińska Katarzyna , Sugajski Mateusz , Buszewska-Forajta Magdalena , Walczak-Skierska Justyna , Railean Viorica , Pomastowski Paweł , Białczak Dorota , Buszewski Bogusław
Published: June 2022

Butter is an important source of essential fatty acids, lipid-soluble vitamins, and antioxidants in the diet. However, this study showed that the presence of the Lacticaseibacillus paracasei strain has a great influence on the fatty acid profile as well as provitamin D3 and vitamin D3 content in the cream—the raw material from which the butter is obtained. The addition of this lactic acid bacteria enriches the cream in 9-hexadecenoic acid, oleic acid, octadeca-9,12-dienoic acid, and conjugated linoleic acid, which exhibit antimutagenic and anticarcinogenic properties. Moreover, a higher level of monounsaturated fatty acids can extend the shelf life of butter in the future. In the present work, we observed that the presence of lactic acid bacteria contributed to an increase in the level of provitamin D after 6 h of incubation and an increase in the levels of vitamin D3 after 24 and 48 h. Fatty acid profiles and the content of vitamins were largely dependent on the presence of light and mixing, which are probably associated with the status of lipid peroxidation.
EPS-Producing Lactobacillus plantarum MC5 as a Compound Starter Improves Rheology, Texture, and Antioxidant Activity of Yogurt during Storage
Authors: Zhao Xuefang , Liang Qi
Published: June 2022

This study evaluated the effects of probiotic Lactobacillus plantarum MC5 on the quality, antioxidant activity, and storage stability of yogurt, to determine its possible application as a starter in milk fermentation. Four groups of yogurt were made with different proportions of probiotic L. plantarum MC5 and commercial starters. The yogurt samples’ rheological properties, texture properties, antioxidant activity, storage stability, and exopolysaccharides (EPS) content during storage were determined. The results showed that 2:1 and 1:1 yogurt samples (supplemented with L. plantarum MC5) attained the highest EPS content (982.42 mg/L and 751.71 mg/L) during storage. The apparent viscosity, consistency, cohesiveness, and water holding capacity (WHC) of yogurt samples supplemented with L. plantarum MC5 were significantly higher than those of the control group (p < 0.05). Further evaluation of antioxidant activity revealed that yogurt samples containing MC5 starter significantly increased in DPPH, ABTS, OH, and ferric iron-reducing power. The study also found that adding MC5 can promote the growth of Streptococcus thermophilus. Therefore, yogurt containing L. plantarum MC5 had favorable rheological properties, texture, and health effects. The probiotic MC5 usage in milk fermentation showed adequate potential for industrial application.
Eggplant Flour Addition in Cookie: Nutritional Enrichment Alternative for Children
Authors: Soares Jaqueline Machado , Teixeira Flávia , Oliveira Mayra Lopes de , Amaral Luane Aparecida do , Almeida Tainá da Silva Fleming de , Souza Gabriel Henrique Oliveira de , Hokama Lais Maluf , Menegassi Bruna , Santos Elisvânia Freitas dos , Novello Daiana
Published: June 2022

This research aimed to evaluate the effect of adding different levels of eggplant flour in cookie on the physicochemical and nutritional characteristics and to verify the sensory acceptability among children. Four eggplant flour cookie formulations were prepared: EF0 (or standard), EF2.5, EF5.0, and EF7.5 (Eggplant Flour 0, 2.5, 5.0 and 7.5%, respectively). The sensory acceptability, physicochemical and nutritional composition were evaluated. The eggplant flour addition of 7.5% to cookie reduced the acceptability (p > 0.05). The samples EF5.0 and EF7.5 showed higher diameter, expansion and thermal factor, while the EF0 and EF2.5 had higher thickness (p < 0.05). The flour addition significantly increased the hardness, Water activity (Aw), Titratable Acidity (TA) and Soluble Solids (SS) in the cookie, however, L* a* and b*, pH and SS/TA ratio values were reduced (p < 0.05). Increased levels of ash, dietary fibers, ascorbic acid, anthocyanins, total phenolic compounds and antioxidant activity were verified on the cookie after eggplant flour addition. Meanwhile, there was a reduction in energy and carbohydrate values. It is concluded that eggplant flour addition up to 5% in cookie maintains the sensory acceptability similar to the standard product when evaluated by children. In addition, it can be considered a viable alternative to improve most of the physicochemical and nutritional characteristics of the product.
Effect of Heterogeneity on the Extension of Ubiquitiformal Cracks in Rock Materials
Authors: Yang Beibei , Cao Xiaoshan , Han Tielin , Li Panfeng , Shi Junping
Published: June 2022

Fracture energy, as an important characteristic parameter of the fracture properties of materials, has been extensively studied by scholars. However, less research has been carried out on ubiquitiformal fracture energy and the main method used by scholars is the uniaxial tensile test. In this paper, based on previous research, the first Brazilian splitting test was used to study the ubiquitiformal crack extension of slate and granite, and the complexity and ubiquitiformal fracture energy of rock material were obtained. The heterogeneity of the material was then characterized by the Weibull statistical distribution, and the cohesive model is applied to the ABAQUS numerical software to simulate the effect of heterogeneity on the characteristics of ubiquitiformal cracks. The results demonstrate that the ubiquitiformal complexity of slate ranges from 1.54 to 1.60, and that of granite ranges from 1.58 to 1.62. The mean squared deviations of the slate and granite ubiquitiformal fracture energy are the smallest compared with the other fracture energies, which are 0.038 and 0.037, respectively. When the homogeneity of the heterogeneous model is less than 1.5, its heterogeneity has a greater influence on the Brazilian splitting strength, and the heterogeneity of the rock is obvious. However, when the homogeneity is greater than five, the effect on the Brazilian splitting strength is much less, and the Brazilian splitting strength tends to be the average strength. Therefore, it is particularly important to study the fracture problem of cracks from the nature of the material structure by combining the macroscopic and mesoscopic views through the ubiquitiform theory.
Comprehensive Review of Polymer and Polymer Gel Treatments for Natural Gas-Related Conformance Control
Authors: Al Brahim Ali , Bai Baojun , Schuman Thomas
Published: June 2022

Conformance problems often exist in natural gas-related activities, resulting in excessive water production from natural gas production wells and/or excessive natural gas production from oil production wells. Several mechanical and chemical solutions were reported in the literature to mitigate the conformance problems. Among the chemical solutions, two classes of materials, namely polymer gels and water-soluble polymers, have been mostly reported. These systems have been mainly reviewed in several studies for their applications as water shutoff treatments for oil production wells. Natural gas production wells exhibit different characteristics and have different properties which could impact the performance of the chemical solutions. However, there has not been any work done on reviewing the applications of these systems for the challenging natural gas-related shutoff treatments. This study provides a comprehensive review of the laboratory evaluation and field applications of these systems used for water control in natural gas production wells and gas shutoff in oil production wells, respectively. The first part of the paper reviews the in-situ polymer gel systems, where both organically and inorganically crosslinked systems are discussed. The second part presents the water-soluble polymers with a focus on their disproportionate permeability reduction feature for controlling water in gas production wells. The review paper provides insights into the reservoir conditions, treatment design and intervention, and the success rate of the systems applied. Furthermore, the outcomes of the paper will provide knowledge regarding the limitations of the existing technologies, current challenges, and potential paths forwards.
Profiling the Tumor-Infiltrating Lymphocytes in Gastric Cancer Reveals Its Implication in the Prognosis
Authors: Yu Weiqiang , Wang Shuaili , Rong Qiqi , Ajayi Olugbenga Emmanuel , Hu Kongwang , Wu Qingfa
Published: June 2022

Gastric cancer is the fifth most common malignancy and the third leading cause of cancer-related mortality worldwide. Immunotherapy offers promising new treatment options for gastric cancer patients; however, it is only effective in a limited fraction of patients. In this study, we evaluated the composition of 22 tumor-infiltrating lymphocytes (TILs) in TCGA Stomach Adenocarcinoma (STAD) using deconvolution-based method by analyzing the publicly available bulk tumor RNA-seq data. The patients were classified into high-TIL and low-TIL subtypes based on their immune cell profiles and prognosis outputs. The differentially expressed genes (DEGs) between the two subtypes were identified, and GO/KEGG analysis showed that broad immune genes, such as PD-L1 and PD-1, were highly expressed in the high-TIL subtype. A comprehensive protein–protein interaction (PPI) network centered on DEGs was built, and 16 hub genes of the network were further identified. Based on the hub genes, an elastic model with 11 gene signatures (NKG7, GZMB, IL2RB, CCL5, CD8A, IDO1, MYH1, GNLY, CXCL11, GBP5 and PRF1) was developed to predict the high-TIL subtype. In summary, our findings showed that the compositions of TILs within the tumor immune microenvironment of stomach cancer patients are highly heterogeneous, and the profiles of TILs have the potential to be predictive markers of patients’ responses and overall survival outcomes.
Association of Depression, Anxiety, Stress and Stress-Coping Strategies with Somatization and Number of Diseases According to Sex in the Mexican General Population
Authors: Brambila-Tapia Aniel Jessica Leticia , Macías-Espinoza Fabiola , Reyes-Domínguez Yesica Arlae , Ramírez-García María Luisa , Miranda-Lavastida Aris Judit , Ríos-González Blanca Estela , Saldaña-Cruz Ana Miriam , Esparza-Guerrero Yussef , Mora-Moreno Francisco Fabián , Dávalos-Rodríguez Ingrid Patricia
Published: June 2022

Somatization and number of diseases are interrelated variables, whose association with stress-coping strategies, according to sex, has not been investigated. Therefore, the aim of this study was to investigate such association in a sample of the Mexican general population. The general population was invited to answer an electronic questionnaire via the social networks—e-mail, WhatsApp and Facebook—by the research team. A sample of 1008 adults was obtained, of which 62.2% were women, in whom we detected higher levels of negative psychological variables, somatization and number of diseases and lower levels of sleep quality. Positive moderate correlations were found between depresion, anxiety and stress with somatization, on one hand, and with the number of diseases, on the other, and negative moderate correlations were found between sleep quality and the two dependent variables. As for the coping strategies, self-blame, behavioral disengagement, denial, self-distraction and substance use were positively correlated with somatization. Of these, self-blame, substance use, and self-distraction also showed a positive correlation with number of diseases in both sexes. Negative correlations were detected for active coping and the two dependent variables in men and for religion and planning with somatization in women. In conclusion, the coping strategies showed significant correlations with somatization and number of diseases in both sexes.
Factors Associated with the Level of Physical Activity in Middle-Aged Colombian People during Lockdown in Response to COVID-19: A Cross-Sectional Study
Authors: García-Garro Patricia Alexandra , Aibar-Almazán Agustín , Rivas-Campo Yulieth , Vega-Ávila Gloria Cecilia , Afanador-Restrepo Diego Fernando , Martínez-Amat Antonio , Afanador-Rodríguez María Isabel , Hita-Contreras Fidel
Published: June 2022

(1) Background: Due to the pandemic caused by COVID-19, mandatory confinement was declared, which generated a decrease in the practice of physical activity (PA). Based on this problem, it was proposed to study the associations between PA in relation to depressive symptoms, quality of sleep, and the quality of life of middle-aged people who work in the university context during compulsory confinement as a result of COVID-19. (2) Methods: A total of 336 middle-aged people (48 ± 6.67) participated in this analytical cross-sectional study. The variable levels of PA, quality of sleep, symptoms of depression, and quality of life were measured with the International Physical Activity Questionary (IPAQ), the Pittsburgh Sleep Quality Index (PSQI), the Zung Self-Rating Depression Scale (ZSDS), and the SF-12v2 questionnaire, respectively. (3) Results: A logistic regression model was used to analyze the relationships between the level of PA and depressive symptoms (OR = 2.053), total sleep duration (OR = 0.495), sleep disturbances (OR = 2.414), quality of sleep (OR = 2.471), use of sleep medication (OR = 0.348), daytime dysfunction (OR = 1.809), general health (OR = 0.949), and physical functioning (OR = 0.987). (4) Conclusions: In middle-aged people, during compulsory confinement, being insufficiently active is a risk for depressive symptoms and disturbances in sleep quality.
Assessment of Parental Knowledge towards Space Maintainer as an Essential Intervention after Premature Extraction of Primary Teeth
Authors: Ali Amel , Hebbal Mamata , Aldakheel Nada , Al Ghamdi Norah , Eldwakhly Elzahraa
Published: June 2022

This study assessed parents’ knowledge about space maintainers as an interceptive strategy after premature loss of primary teeth. Methods and Material: A cross-sectional questionnaire-based descriptive study was conducted on a sample of 600 parents; 456 (76%) were females, and 144 (24%) were males, recruited from an outpatient dental clinic at Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia. The questionnaire consisted of two sections; the first section collected sociodemographic data of participants, and the second section gathered parental knowledge of space maintainers. The research ethics committee granted ethical approval, and informed consent was obtained before participation. Results: 600 parents participated in this study. The total mean knowledge score regarding space maintainers was 7.97 ± 3.38. The mean knowledge score was 7.06 ± 2.99 for male parents and 8.26 ± 3.45 for female parents. The difference in the mean knowledge score between female and male parents was statistically significant (p < 0.001). Additionally, there was a statistically significant difference in the knowledge score and parents’ age groups, with parents having the highest knowledge in the 30–40 age group (p = 0.0197). There was a positive correlation between knowledge scores and the number of children. Parents with one child showed less knowledge than those with two to four children (p = 0.0121). Conclusions: Participants’ knowledge regarding space maintainers was 49.8%, which is considered inadequate. It was deemed essential to increase knowledge among parents about space maintainers as an interceptive approach after premature loss of primary teeth.
Leaf Epidermal Morphology of Ten Wild Tree Peonies in China and Its Taxonomic Significance
Authors: Jia Wenqing , Wang Yanli , Qi Qing , He Songlin , Mi Zhaorong , Zhu Xiaopei
Published: June 2022

This research reports for the first time the epidermal characteristics of 10 wild tree peonies belonging to the sect. Moutan group. The leaf micromorphology of 10 wild tree peonies—P. qiui, P. decomposita, P. jishanensis, P. ostii, P. delavayi, P. lutea, P. potanini, P. rockii, P. ludlowii and P. cathayana—were investigated by light and scanning electron microscopy. The characteristics of the leaf epidermis were found to be constant at the species level, but variable among species. Patterns of anticlinal walls were slightly wavy to wavy, very wavy, and straight to curved. All studied tree peonies presented stomata only on the abaxial surfaces of the leaves. The stomatal apparatus was elliptical or rectangular. Stomatal density was highest on the abaxial surface in P. qiui (300.25 per mm2), and lowest in P. jishanensiss (198.41 per mm2). Stomatal Index was highest on the adaxial surface of P. potanini (27.30%), and lowest in P. ludlowii (18.35%). Trichomes were observed in four studied peonies, which appeared only on the abaxial surface of the leaves, and three basic types of trichomes were identified. The long conical trichomes were distinctive of P. jishanensis, and the flat-shaped trichomes were characteristic of P. qiui, P. rockii and P. cathayana, and commonly occurred in the intervenous region and leaf veins. Stomatal shape, stomatal density, anticlinal wall patterns and trichomes may be of great value and significance for the classification of wild tree peonies. The principal component analysis showed that the component 1, component 2 and component 3 were the most components and nearly 79% of the observed variation. The key to the identification of wild tree peonies based on trichomes and stomata diversity was provided.
Decrease in the Water Level of Lake Prespa (North Macedonia) Studied by Remote Sensing Methodology: Relation with Hydrology and Agriculture
Authors: Soria Juan , Apostolova Nadezda
Published: June 2022

The Ohrid-Prespa lake system is the oldest and most diverse permanent lake system in Europe, dating from the Pliocene era and aged at over 4Ma. Its smaller component is Lake Macro Prespa (thereafter called Prespa), shared by North Macedonia, Albania, and Greece. Lake Prespa’s depth was reported as 14 m mean and 48 m maximum before its major water level decline. The lake is highly sensitive to external impacts, including climate change, and has been suffering major water loss for decades. A lake-level decline of almost 10 m was documented between 1950 and 2009 due to restricted precipitation and increased water abstraction for irrigation. This study describes the changes in the surface size of Prespa Lake and the vegetation/land use in the surrounding area in the period 1984–2020 using satellite images (remote sensing, Landsat 5 & 8 images by United States Geological Survey). The lake lost 18.87 km2 of surface in this period (6.9% of its size, dropping from 273.38 km2 to 254.51 km2). Water loss was greater in the period 1987–1993 and 1998–2004. The Analysis of Normalized Difference Vegetation Index (NDVI) in the area (app. 4950 km2) surrounding Lake Prespa revealed an increase in the mean NDVI values over the period studied (1984–2020), pointing to a general increase in vegetation. Areas with NDVI > 0.13 increased from 78% in 1984 to 86% in 2020, while those with the highest vegetation intensity (NDVI > 0.45) increased by 40%. These changes in vegetation may be related to the water loss of the lake.
Association between Sleep Duration and Physical Fitness in Children Aged 3–6 Years: A Cross-Sectional Study from China
Authors: Xiong Xin , Cui Yinchen , Zhang Weinan , Zhao Chenlin , Wu Jiahui , Li Haifeng , Zhen Zhiping , Sun Jian
Published: June 2022

Aim: To explore associations between sleep duration and physical fitness (PF) of children aged 3–6 years. Methods: This study investigated the sleep duration and PF data of children aged 3–6 years by stratified random sampling. The restricted cubic spline model and binary logistic regression analysis were mainly used for the empirical analysis of the correlation effect between sleep duration and PF. The final data had a total of 21,857 children, of which 11,245 (51.45%) were boys and 10,612 (48.55%) were girls. Results: The PF level of the children in this study showed a relatively positive level (pass rate = 93.6%), and 19.7% of them had abnormal sleep duration; the results of the restricted cubic spline showed an inverted U-shaped association between the level of PF and the risk of abnormal sleep duration (X2 = 28.13, p < 0.0001). The results of logistic regression analysis showed that children with abnormal sleep duration were more likely to have a low PF, body morphology and motor ability levels at an OR (95% CI) of 1.077 (1.023–1.133), 1.077 (1.016–1.142) and 1.035 (1.08–1.062), respectively. The results of the bias correlation analysis showed varying degrees of correlation between sleep duration and various components of children’s PF. Conclusion: Insufficient or excessive amounts of sleep were significantly associated with PF in children, with abnormal sleep duration leading to reduced levels of PF and its components.
Experimental Study on Panic during Simulated Fire Evacuation Using Psycho- and Physiological Metrics
Authors: Deng Kaifeng , Li Meng , Wang Guanning , Hu Xiangmin , Zhang Yan , Zheng Huijie , Tian Koukou , Chen Tao
Published: June 2022

Under circumstances of fire, panic usually brings uncertainty and unpredictability to evacuation. Therefore, a deep understanding of panic is desired. This study aims to dig into the underlying mechanism of fire evacuation panic by measuring and analysing psycho- and physiological indicators. In the experiment, participants watched a simulated train station within which three sets of stimuli were triggered separately. Eye movement and brain haemodynamic responses were collected during the watch, while questionnaires and interviews of emotions were conducted after. The analysed physiological indicators include the amplitude of pupil dilation, the time ratios of fixation and saccade, the binned entropy of gaze location, and the brain activation coefficients. The results of this research indicate that fire evacuation panic can be broken down into two elements. (1) Unawareness of situation: less knowledge of the situation leads to a higher level of panic; (2) Intensity of visual stimulation: the panic level is escalated with increased severity of fire that is perceived.