bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Cementitious Capillary Crystalline Waterproofing Materials on the Mechanical and Impermeability Properties of Engineered Cementitious Composites with Microscopic Analysis
Authors: Tan Yan , Zhao Ben , Yu Jiangtao , Xiao Henglin , Long Xiong , Meng Jian
Published: February 2023

Building structures are prone to cracking, leakage, and corrosion under complex loads and harsh marine environments, which seriously affect their durability performance. To design cementitious composites with excellent mechanical and impermeability properties, Engineered Cementitious Composites (ECCs) doped with ultrahigh molecular weight polyethylene short-cut fibers (PE-ECCs) were used as the reference group. Different types (XYPEX-type from Canada, SY1000-type from China) and doses (0%, 0.5%, 1.0%, 1.5%, 2.0%) of Cementitious Capillary Crystalline Waterproofing materials (CCCWs) were incorporated. The effect of CCCWs on the mechanical and impermeability properties of PE-ECCs, and the microscopic changes, were investigated to determine the best type of CCCW to use and the best amount of doping. The results showed that with increasing the CCCW dosage, the effects of both CCCWs on the mechanical and impermeability properties of PE-ECC increased and then decreased, and that the best mechanical and impermeability properties of PE-ECC were achieved when the CCCW dosing was 1.0%. The mechanical properties of the PE-ECC were more obviously improved by XYPEX-type CCCW, with a compressive strength of 53.8 MPa, flexural strength of 11.8 MPa, an ultimate tensile stress of 5.56 MPa, and an ultimate tensile strain of 7.53 MPa, which were 37.95%, 53.25%, 14.17%, and 21.65% higher than those of the reference group, respectively. The effects of the two CCCWs on impermeability were comparable. CCCW-PE-ECC(X1.0%) and CCCW-PE-ECC(S1.0%) showed the smallest permeation heights, 2.6 mm and 2.8 mm, respectively. The chloride ion diffusion coefficients of CCCW-PE-ECC(X1.0%) and CCCW-PE-ECC(S1.0%) exhibited the smallest values, 0.15 × 10−12 m2/s and 0.10 × 10−12 m2/s, respectively. Micromorphological tests showed that the particle size of the XYPEX-type CCCW was finer, and the intensity of the diffraction peaks of C-S-H and CaCO3 of PE-ECC increased after doping with two suitable doping amounts of CCCW. The pore structure was improved, the surface of the matrix was smoother, and the degree of erosion of hydration products on the fiber surface was reduced after chloride ion penetration. XYPEX-type CCCW demonstrated a more obvious improvement in the PE-ECC pore structure.
Utilization of Mechanically Recycled Carbon Fibers in Vinyl Ester Composites
Authors: AlHarmoodi Khaled , Idrisi Amir Hussain , Mourad Abdel-Hamid Ismail , Abu-Jdayil Basim
Published: February 2023

As we enter the twenty-first century, the aviation sector is expected to thrive as flying becomes the primary mode of transportation between states or nations. With such a demand, there is a corresponding need to manufacture aircraft components. The study focused on recycling carbon fiber composites received from the STRATA company, which were cut-off/waste material generated during the manufacture of airplane components. The cut-offs were then reduced to powder form using a standard face milling machine in three sizes (90, 150, and 250 µm). After, the powder was utilized to fabricate vinyl ester composites with four weight percentages (10%, 20%, 30%, and 40%). The results demonstrate that the tensile strength of all composites had risen by 30.2%, 21.3%, and 17.6% for 90, 150, and 250 µm respective with the addition of 20 wt% of reinforcement. Furthermore, subsequently decreased with the additional reinforcement for all particle sizes. The compressive strength increased by 30% from 187.5 MPa to 244 MPa with 10 wt% of recycled carbon powder composite of 90μm particle size. However, samples prepared with 150 μm and 250 μm fiber size show approximately 17% and 1% increase in the compression strength with the addition of 10wt% of recycled carbon powder. A similar trend was observed for the flexural strength with an highest increase of 9% for 90 µm particle size with addition of 20 wt% reinforcement. Nonetheless, the SEM images revealed that the fiber–matrix bonding was weak, proved through the clean pullout fibers at the fracture surfaces.
Numerical Analysis of Curing Residual Stress and Strain in NEPE Propellant Grain
Authors: Liu Xiangyang , Xie Xuyuan , Zhou Dongmo , Wang Ruimin
Published: February 2023

In order to investigate the formation mechanism of the residual stress and residual strain in a nitrate ester plasticized polyether (NEPE) propellant grain during the curing and cooling process, the temperature, curing degree and stress/strain of the NEPE propellant grain during the curing and cooling process were analyzed via ABAQUS finite element software. The results indicate that there is a temperature gradient in the NEPE propellant grain during curing at 50 °C. The maximum temperature difference is about 5 °C and the maximum temperature is located on the center of propellant grain. At the end of curing, the temperature in the interior of the grain tends to be uniform. The curing degree in the NEPE propellant grain during the curing process has the same trend as temperature. The residual stress/strain of the NEPE propellant grain during the curing and cooling down processes are mainly composed of curing shrinkage stress/strain in the curing process and thermal stress/strain in the cooling down process. The curing shrinkage stress and strain in the curing process account for 19% and 31% of the whole process, respectively. The thermal stress and thermal strain in cooling down process account for 75% and 69% of the whole process, respectively. The thermal stress and thermal strain in the curing process can nearly be ignored. The residual stress and residual strain calculated by the traditional method is larger than that obtained in this paper. The maximum deviation of the residual stress and residual strain are about 8% and 17%, respectively.
Effective Preservation of Chilled Pork Using Photodynamic Antibacterial Film Based on Curcumin-β-Cyclodextrin Complex
Authors: Wu Jingru , Li Jing , Xu Fang , Zhou Arong , Zeng Shaoxiao , Zheng Baodong , Lin Shaoling
Published: February 2023

A biodegradable photodynamic antibacterial film (PS-CF) was prepared using the casting method, with κ-Carrageenan (κ-Car) as the film-forming substrate and curcumin-β-cyclodextrin (Cur-β-CD) complex as photosensitizer. Chilled pork samples were coated with PS-CF and stored at 4 °C to investigate the effects of PS-CF combined with LED light irradiation (425 nm, 45 min) (PS+L+) on pork preservation during 10 days of storage. The total viable count (TVC) of bacteria, total volatile basic nitrogen value (TVB-N) and the pH of pork treated with PS+L+ were all lower than the control, and the water-holding capacity (WHC) was higher. Ten days later, the TVB-N value was 12.35 ± 0.57 mg/100 g and the TVC value was 5.78 ± 0.17 log CFU/g, which was within the acceptable range. Sensory evaluation determined that the color, odor, and overall acceptability of pork treated with PS+L+ were significantly better than the control. These findings suggest that PS+L+ treatment effectively extended the shelf life of chilled pork from ~4–5 to 10 days. Correlation analysis showed that the sensory quality of the chilled pork significantly correlated with total bacterial counts, TVB-N and thiobarbituric acid reactive substances (TBARS) (p < 0.05), suggesting that these biomarkers could be used as standard indicators for evaluating the freshness of chilled pork. These findings demonstrate the effectiveness of Cur-β-CD photodynamic antibacterial film for the preservation of chilled pork and provide a theoretical basis for the application of the film for the preservation of fresh food in general.
Polylactide—Meso-Substituted Arylporphyrin Composites: Structure, Properties and Antibacterial Activity
Authors: Tertyshnaya Yulia V. , Lobanov Anton V. , Morokov Egor S. , Buzanov Grigorii A. , Abushakhmanova Zubarzhat R.
Published: February 2023

The structural features and antibacterial properties of polymer–porphyrin composites were investigated. Meso-substituted arylporphyrin 0.2–0.5 wt.% was immobilized in a polylactide matrix. The immobilization of porphyrin causes a bathochromic shift and splitting of the Soret band. This study of the morphology of the obtained composites demonstrated a uniform distribution of the meso-substituted arylporphyrin in the polylactide matrix. It was determined by the X-ray diffraction analysis that porphyrin does not affect the α-form of polylactide crystalline formations. However, its addition into the polymer somewhat reduces the melting point (by 1–2 °C) and the degree of crystallinity of polylactide (by 3–4%). The elastic characteristics of the resulting systems were determined by the ultrasonic method, and a decrease in the density of the samples with an increase of the arylporphyrin content was shown. According to the results of the biological test, the dark toxicity of the obtained composites against the microorganisms Staphylococcus aureus, Salmonella Typhimurium and Escherichia coli was shown. Immobilizates containing 0.4 and 0.5 wt.% porphyrin showed the best antibacterial effect. The antibacterial activity of the studied composites makes it possible to attribute the polylactide–porphyrin systems to promising materials in the field of medicine and bioengineering.
Carbonized Leather Waste: A Review and Conductivity Outlook
Authors: Stejskal Jaroslav , Ngwabebhoh Fahanwi Asabuwa , Sáha Petr , Prokeš Jan
Published: February 2023

The carbonization of collagen-based leather waste to nitrogen-containing carbon is reviewed with respect to the preparation, characterization of carbonized products, and applications proposed in the literature. The resulting nitrogen-containing carbons with fibrous morphology have been used as adsorbents in water pollution treatment, in electrocatalysis, and especially in electrodes of energy-storage devices, such as supercapacitors and batteries. Although electrical conductivity has been implicitly exploited in many cases, the quantitative determination of this parameter has been addressed in the literature only marginally. In this report, attention has been newly paid to the determination of conductivity and its dependence on carbonization temperature. The resulting powders cannot be compressed into pellets for routine conductivity determination. A new method has been used to follow the resistivity of powders as a function of pressure up to 10 MPa. The conductivity at this pressure increased from 9.4 × 10−8 S cm−1 for carbonization at 500 °C to 5.3 S cm−1 at 1000 °C. The conductivity of the last sample was comparable with conducting polymers such as polypyrrole. The carbonized leather thus has the potential to be used in applications requiring electrical conduction.
Preparation and Interfacial Properties of Hydroxyl-Containing Polyimide Fibers
Authors: Du Jiang , Pu Chuanzhi , Sun Xianyu , Wang Qi , Niu Hongqing , Wu Dezhen
Published: February 2023

Developing polyimide (PI) fibers with excellent interfacial adhesion and high mechanical properties for the PI fiber-reinforced polymer matrix composites (PFRPs) industry has been challenging. In this work, 4,4′-diamino-(1,1′-biphenyl)-3,3′-diol (HAB) diamine was introduced into the rigid molecular chains, and the high-performance PI fibers, presenting an interfacial shear strength (IFSS) value of 46.33 MPa, tensile strength of 2.62 GPa, and modulus of 100.15 GPa, were successfully manufactured when the content of HAB in mixed diamines was 30 mol %. Fourier transform infrared (FTIR) spectroscopy identified the presence of intermolecular H-bonding interactions, and 2D small-angle X-ray scattering indicated that the introduction of HAB moiety contributed to reducing the radii of microvoids in the fibers, which were considered to be the key factors leading to a significant enhancement in the mechanical properties of the fibers. X-ray photoelectron spectroscopy (XPS) and the static contact angle intuitively illustrated that the synthetic fiber surface contained active hydroxyl groups. The IFSS value of PI fiber/epoxy resin composites (PI/EPs) was 56.47 MPa when the content of HAB reached 70 mol %. Failure morphologies confirmed that the interfacial adhesion of PI/EPs was enhanced owing to the surface activity of PI fibers. Consequently, this study provides an effective strategy to the long-standing problems of high mechanical performances and poor surface activity for traditional PI fibers used in the PFRPs industry.
Material-Preserving Extrusion of Polyamide on a Twin-Screw Extruder
Authors: Schall Christoph , Altepeter Matthias , Schöppner Volker , Wanke Sven , Kley Marina
Published: February 2023

In the context of plastics recycling, plastics are processed several times. With each new melting and extrusion the plastic is damaged, which can have a negative effect on product properties. To counteract material damage, special additives such as chain extenders can be used, which are intended to lead to post-polymerization during processing. A linear chain extension is important here, as branching and crosslinking can lead to uncontrolled changes in the plastic’s properties. To investigate the suitability of specialized linear chain extenders for polyamides, a polyamide-6 was processed several times and the molar mass distribution was evaluated after each extrusion cycle. Three series of tests were carried out. First, the plastic was regranulated five times without additives and twice with different concentrations of chain extenders on a twin-screw extruder. The results of the study show that not only can molar mass degradation be prevented with the appropriate additive, it is even possible to achieve a material buildup during processing. In our experiments, the polydispersity of the molar mass distribution remained nearly identical despite multiple extrusions. Thus, reactive extrusion makes it possible for the corresponding plastics to be processed several times without the molar mass decreasing. If a sufficiently pure material flow can be ensured during recycling, the number of possible reprocessings of the plastic can be significantly increased without the need to add virgin material.
Optimization of Alkaline Extraction of Xylan-Based Hemicelluloses from Wheat Straws: Effects of Microwave, Ultrasound, and Freeze–Thaw Cycles
Authors: Puițel Adrian Cătălin , Suditu Gabriel Dan , Drăgoi Elena Niculina , Danu Maricel , Ailiesei Gabriela-Liliana , Balan Cătălin Dumitrel , Chicet Daniela-Lucia , Nechita Mircea Teodor
Published: February 2023

The alkaline extraction of hemicelluloses from a mixture of three varieties of wheat straw (containing 40.1% cellulose, 20.23% xylan, and 26.2% hemicellulose) was analyzed considering the following complementary pre-treatments: freeze–thaw cycles, microwaves, and ultrasounds. The two cycles freeze–thaw approach was selected based on simplicity and energy savings for further analysis and optimization. Experiments planned with Design Expert were performed. The regression model determined through the response surface methodology based on the severity factor (defined as a function of time and temperature) and alkali concentration as variables was then used to optimize the process in a multi-objective case considering the possibility of further use for pulping. To show the properties and chemical structure of the separated hemicelluloses, several analytical methods were used: high-performance chromatography (HPLC), Fourier-transformed infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (1H-NMR), thermogravimetry and derivative thermogravimetry analysis (TG, DTG), and scanning electron microscopy (SEM). The verified experimental optimization result indicated the possibility of obtaining hemicelluloses material containing 3.40% glucan, 85.51% xylan, and 7.89% arabinan. The association of hot alkaline extraction with two freeze–thaw cycles allows the partial preservation of the hemicellulose polymeric structure.
Ballistic Response of a Glass Fiber Composite for Two Levels of Threat
Authors: Ojoc George Ghiocel , Chiper Titire Larisa , Munteniță Cristian , Pîrvu Cătălin , Sandu Simona , Deleanu Lorena
Published: February 2023

This paper presents the behavior of composite panels based on glass fiber unidirectional fabrics and a bi-component epoxy resin under ballistic impacts that characterize two threat levels: FB2 and FB3, according to EN 1523:2004. The tested panels had characteristics kept in narrow ranges: thickness 18.26 ± 0.22 mm, mass ratio fabrics/panel 0.788 ± 0.015, surface density 27.51 ± 0.26 kg/m2. After testing the panels, the failure mechanisms of the panel were evidenced by scanning electron microscopy and photographs. Here the authors present a finite-element model at meso scale that was used for evaluating if the composite, initially tested at level FB2 (9 mm FMJ, v0 = 375 m/s), could withstand the higher level of impact, FB3 (projectile type 0.357 Magnum and impact velocity of v0 = 433 m/s). Simulation was performed in Explicit Dynamics (Ansys), keeping the same target but changing the projectile for the two different levels of threat. The results of the simulation were encouraging for making tests at level FB3, indicating the importance of alternating actual tests with simulations in order to achieve better protection with reduced surface weight. The simulation illustrated differences in impact duration and number of layers broken on the panel for each level. Validation of the model was based on the number of broken layers and the dimension of the delamination zone between the last two layers. Scanning electron microscopy was used for identifying failure mechanisms at the micro and meso scale. We found that damage to the composite was intensively dependent on impact velocity, this being quantitatively evaluated using the number of layers broken, the effect of delamination on separating layers and the deformation of the last layer.
Polar-Functionalized Polyethylenes Enabled by Palladium-Catalyzed Copolymerization of Ethylene and Butadiene/Bio-Based Alcohol-Derived Monomers
Authors: Zong Yanlin , Wang Chaoqun , Zhang Yixin , Jian Zhongbao
Published: February 2023

Polar-functionalized polyolefins are high-value materials with improved properties. However, their feedstocks generally come from non-renewable fossil products; thus, it requires the development of renewable bio-based monomers to produce functionalized polyolefins. In this contribution, via the Pd-catalyzed telomerization of 1,3-butadiene and three types of bio-based alcohols (furfuryl alcohol, tetrahydrofurfuryl alcohol, and solketal), 2,7-octadienyl ether monomers including OC8-FUR, OC8-THF, and OC8-SOL were synthesized and characterized, respectively. The copolymerization of these monomers with ethylene catalyzed by phosphine–sulfonate palladium catalysts was further investigated. Microstructures of the resultant copolymers were analyzed by NMR and ATR-IR spectroscopy, revealing linear structures with incorporations of difunctionalized side chains bearing both allyl ether units and polar cyclic groups. Mechanical property studies exhibited better strain-at-break of these copolymers compared to the non-polar polyethylene, among which the copolymer E-FUR with the incorporation of 0.3 mol% displayed the highest strain-at-break and stress-at-break values of 940% and 35.9 MPa, respectively.
Assessing Crimp of Fibres in Random Networks with 3D Imaging
Authors: Hewavidana Yasasween , Balci Mehmet N. , Gleadall Andrew , Pourdeyhimi Behnam , Silberschmidt Vadim V. , Demirci Emrah
Published: February 2023

The analysis of fibrous structures using micro-computer tomography (µCT) is becoming more important as it provides an opportunity to characterise the mechanical properties and performance of materials. This study is the first attempt to provide computations of fibre crimp for various random fibrous networks (RFNs) based on µCT data. A parametric algorithm was developed to compute fibre crimp in fibres in a virtual domain. It was successfully tested for six different X-ray µCT models of nonwoven fabrics. Computations showed that nonwoven fabrics with crimped fibres exhibited higher crimp levels than those with non-crimped fibres, as expected. However, with the increased fabric density of the non-crimped nonwovens, fibres tended to be more crimped. Additionally, the projected fibre crimp was computed for all three major 2D planes, and the obtained results were statistically analysed. Initially, the algorithm was tested for a small-size, nonwoven model containing only four fibres. The fraction of nearly straight fibres was computed for both crimped and non-crimped fabrics. The mean value of the fibre crimp demonstrated that fibre segments between intersections were almost straight. However, it was observed that there were no perfectly straight fibres in the analysed RFNs. This study is applicable to approach employing a finite-element analysis (FEA) and computational fluid dynamics (CFD) to model/analyse RFNs.
Boiling Heat Transfer Characteristics of Porous Microchannel with Pore-Forming Agent
Authors: Lei Qinhui , Zhang Donghui , Feng Lei , Mao Jijin , Chen Daifen
Published: February 2023

Traditional microchannel needs to face the flow-reversal difficulty in high heat fluxes due to limited space. It results in large pressure and temperature fluctuation. Porous microchannels arouse more interest to provide a new solution to this problem. Flow boiling experiments in porous microchannels with PFA were investigated. Porous microchannels were sintered by 10 μm (or 30 μm) spherical copper particles with pore-forming agent (Na2CO3, 60–90 μm). Porous microchannels were composed of 23 parallel porous microchannels with 600 μm in width and 1200 μm in depth.The addition of PFA (pore-forming agent) could increase the sample porosity. For Q10 series, sample porosities increase from 20.4% to 52.9% with the PFA percentage change from 0% to 40%, while for the Q30 series they increase from 26.6% to 47.5%. Experimental results showed the boiling heat transfer coefficient (HTC) reached the maximum at the moderate porosity for both Q10 and Q30 series. Too large or too small porosity would degrade boiling heat transfer performance. It demonstrated that there existed an optimal range of PFA content for sintered microchannels. PFA content has a minor effect on the average pressure drop and would not cause the rapid increase in flow resistance. Visual observation disclosed that the sample porosity would affect the pressure instability significantly. The sample with moderate porosity showed periodic pressure fluctuation and could establish rhythmical boiling. Particle size also exerted a certain influence on the boiling heat transfer performance. Q30 series could achieve higher HTC and CHF (Critical heat flux) than Q10 series. This is attributed to the larger ratio of layer-thickness-to-particle-size (δ/d) for Q10-series samples.
Density Functional Theory Study of the Electronic Structures of Galena
Authors: Kang Jianxiong , An Yanni , Xue Jiwei , Ma Xiao , Li Jiuzhou , Chen Fanfan , Wang Sen , Wan He , Zhang Chonghui , Bu Xianzhong
Published: February 2023

In this study, the electronic structure of the galena surface was investigated using the first-principle calculation. The results of band structure, density of states, Mulliken population distribution, and frontier orbital analysis showed that galena was the p-type semiconductor of the direct band gap. During the formation of galena crystals, the 3p orbital of the S and the 6p orbital of the Pb played a primary role. Additionally, S atoms in galena quickly lose electrons and are oxidized, while Pb readily reacts with anions. The results of surface structure and electronic properties, such as surface relaxation, surface state energy levels, electronic density of states, and atomic charge distribution showed that the electronics in the 6p orbital of the Pb are transferred to the 3p orbital of the S in galena crystal. They caused the change of atomic valence states in lattice surfaces. The total electron number of the outermost surface layer was also higher than the bulk, giving the galena surface the properties of electron enrichment. This research is of great significance for developing new galena flotation reagents and for further in-depth exploration of the adsorption of reagents on the galena surface.
Using Quantile Mediation Analysis to Explore Relationships among Hydropower Energy Consumption, Economic Growth, and Carbon Dioxide Emissions in Taiwan
Authors: Hsu Tzu-Kuang , Yeh Yuan-Sheng , Granmo Anders
Published: February 2023

In this study, we employ the novel method of quantile mediation analysis to explore dynamic relationships among hydropower energy consumption, economic growth, and carbon dioxide emissions in Taiwan during the period between 1990 and 2020. The empirical results show that hydropower energy consumption only has a direct effect on reducing carbon dioxide emissions at a 0.2 distribution of carbon dioxide emissions. Moreover, results indicate that economic growth does not have a mediating effect between hydropower energy consumption and carbon dioxide emissions at any distribution of carbon dioxide emissions. Lastly, evidence produced by this study supports the existence of an environmental Kuznets curve in the context of Taiwan.
From Pollution to Green and Low-Carbon Island Revitalization: Implications of Exhibition-Driven Sustainable Tourism (Triennale) for SDG 8.9 in Setouchi
Authors: Cai Gangwei , Wang Jie , Lue Anyi , Xu Shiwen , Wu Qian , Liu Kang , Gao Tianyu , Du Pengcheng , Lei Bin
Published: February 2023

After the severe industrial pollution from World War II, the Setouchi Sea areas and its islands (the Triennale hosting areas) experienced severe economic and population shrinkage. The target of SDG 8.9 is to promote “direct tourism GDP” and “tourism-related jobs” by devising and implementing policies (e.g., some Triennale and Biennale) for sustainable tourism. Triennale-driven tourism is an essential component of sustainable tourism and city revitalization, lasting almost 20 years in Japan. The current paper attempts an empirical analysis into the positive impacts of exhibition-driven sustainable tourism for SDG 8.9 in these rural islands (from pollution to green and low-carbon islands revitalization). The panel data of “pollution load of living environment items” by cities in Japan and “tourists, income, and population” from 14 areas in Kagawa were monitored using multiple methods, such as descriptive and inferential statistics (the one-way ANOVA test and Simple Linear Regression (SLR)). It is a new attempt to devise and implement policies and theories for a sustainable tourism-related industry and its SDGs. Therefore, the present findings offer meaningful implications in academia and industry, not only in Setouchi Sea areas but also for similar areas in and out of Japan.
Development of a Software Tool for Visualizing a Mine (Wellbore) in the Industrial Drilling of Oil Wells
Authors: Abu-Abed Fares , Pivovarov Kirill , Zhironkin Vitaly , Zhironkin Sergey
Published: February 2023

The purpose of the software development presented in the article is to obtain detailed information about the surface of the walls in wells necessary for more efficient and safe drilling and casing of the wellbore. The developed software of the automated system “LogPWin” allows obtaining a clear idea of the mine itself, as well as reducing the time spent on processing and analyzing the model obtained during the logging process. A software product developed as a result of the work provides visualization of data coming from an acoustic profiler, giving a visual and informative idea of the object of study. The program gives detailed information about the surface of the mine’s walls through 3D modeling. It possesses the possibility of rotating and scaling the object; there is also a color palette that can be changed depending on the incoming data. The program can be applied in the oil and gas industry and mining, as well as when drilling wells for other purposes. The program interface is quite clear and simple. The structure of the program is made in such a way that it allows obtaining data for building an object not only in real time, but also through interaction with a ready-made .txt file.
Prediction of Temperature and Viscosity Profiles in Heavy-Oil Producer Wells Implementing a Downhole Induction Heater
Authors: Ramírez Javier , Zambrano Alexander , Ratkovich Nicolás
Published: February 2023

Very high viscosity significantly impacts the mobility of heavy crude oil representing difficulties in production and a decrease in the well’s efficiency. Downhole electric heating delivers a uniform injection of heat to the fluid and reservoir, resulting in a substantial decrease in dynamic viscosity due to its exponential relationship with temperature and a drop in frictional losses between the production zone and the pump intake. Therefore, this study predicts temperature and viscosity profiles in heavy oil-production wells implementing a downhole induction heater employing a simplified CFD model. For the development of the research, the geometry model was generated in CAD software based on the geometry provided by the BCPGroup and simulated in specialized CFD software. The model confirmed a 46.1% effective decrease of mean 12° API heavy-oil dynamic viscosity compared with simulation results without heating. The developed model was validated with experimental data provided by the BCPGroup, obtaining an excellent agreement with 0.8% and 15.69% mean error percentages for temperature and viscosity, respectively. Furthermore, CFD results confirmed that downhole electrical induction heating is an effective method for reducing heavy-oil dynamic viscosity; however, thermal effects in the reservoir due to heat penetration were insignificant. For this study, the well will remain stimulated.
The Development and Dissemination of Pro-Environmental Dharma among Taiwan’s Humanistic Buddhists
Authors: Zimmerman-Liu Teresa
Published: February 2023

In the early 1990s, two of Taiwan’s humanistic Buddhist groups—Buddhist Tzu Chi Compassionate Relief Foundation (Tzu Chi) and Dharma Drum Mountain (DDM)—began incorporating modern environmentalism as a major component in their religious teachings, practices, and behavioral norms. Neither group had been clearly pro-environmental before the 1990s, but Venerable Cheng Yen, the founding master of Tzu Chi, and Venerable Sheng Yen, the founding master of DDM, redefined and expanded Buddhist teachings and practices to include modern concepts and practices of environmental sustainability as central components of their dharmas. This comparative ethnographic study contributes to scholarship with findings regarding how and why the two groups developed and disseminated pro-environmental dharma: (1) both groups began promoting environmentalism as a moral, religious response to Taiwan’s waste management crisis of the early 1990s; (2) both groups tied their pro-environmental teachings to two of the most popular elements of Buddhist dharma among Chinese humanistic Buddhists—the bodhisattva path and pure land teachings; (3) both groups fully integrated environmental teachings, practices, and behavioral norms into all aspects of their organizations; and (4) both groups adjusted the framing of their pro-environmental messages to match specific audiences in their work in order to promote environmentalism in Taiwan’s society.
Jon Sobrino and ‘the Crucified People’
Authors: Tombs David
Published: February 2023

‘The crucified people’ became a key theological concern in the writings of Jon Sobrino SJ in the 1990s. This article examines how and why Sobrino made this concern a central element in his theology at the time. Section 2 discusses what Sobrino has described as his ‘awakening from the sleep of inhumanity’ in the 1970s as he encountered liberation theology in El Salvador following his doctoral studies in Frankfurt. Section 3 examines three figures in the Salvadoran Church who influenced Sobrino: Ignacio Ellacuría (assassinated 1989); Oscar Romero (assassinated 1980); and Rutilio Grande (assassinated 1977). All three paid with their lives for their work in the Church. Section 4 examines the understanding of the crucified people offered by Ellacuría in 1978, and the encouragement for this idea in the words of Romero and Grande in 1977. Sections 5 and 6 turn to the use of the term as used by Sobrino himself. Section 5 argues that Sobrino’s early Christological writings are quite cautious in their use of this idea. The murder of Ellacuría by the military in November 1989 at the Central American University—alongside the killing of five fellow Jesuits, their housekeeper, and her daughter—appears to be the pivotal event that prompts Sobrino’s bolder discussion in publications from 1989 onwards (Section 6).
Experience of Wondering Awe and Perception of Nature as a Resource during the COVID-19 Pandemic—Findings from a Cross Sectional Survey of Participants in Jerusalem
Authors: Büssing Arndt , Zini Avraham , Vered Yuval
Published: February 2023

During the COVID-19 pandemic most people had to cope with the negative implications of the lockdowns, and perceived times of social isolation and loneliness, and thus low wellbeing. Among the best predictors of positive changes of pandemic related attitudes and behaviors was the experience of pausing in wondering awe with subsequent feelings of gratitude. As these observations came from a secular society with a Christian background, we now aimed to analyzed to what extend Jewish people from Israel were experiencing such moments of wondering awe during the COVID-19 pandemic, and how these perceptions are related to their psychological wellbeing. For that purpose, between June and July 2021 a cross-sectional survey with standardized questionnaires was applied among 147 participants from Jerusalem. Those with high wellbeing and those who can rely on their faith as a resource to cope with the pandemic were more intensively perceiving moments of Awe/Gratitude. Awe/Gratitude and a low perception of COVID-19 related stressors were the best predictors of participants’ psychological wellbeing. Against our expectation, Awe/Gratitude was not significantly associated with the experience of nature and enjoying reflective times of silence. Both resources, Awe/Gratitude as a an experiential aspect of spirituality and Nature/Silence as a source to encounter the sacred in one’s life, are relevant and should be supported.
Paradisi porta—An Iconographic Analysis of Mary as a Humanity’s Mediator in the Light of Medieval Liturgical Hymns
Authors: Salvador-González José María
Published: February 2023

This article aims to highlight the rich doctrinal meanings underlying the textual and iconic designation of the Virgin Mary as the gate of Heaven, a highly brilliant metaphor used by writers and artists to symbolize her saving mediation before her divine Son on behalf of humankind. To justify our interpretations of this textual and iconic symbol, we will proceed first by analyzing an abundant set of fragments of medieval liturgical hymns, which designate the Virgin Mary as the “gate of Paradise” (porta Paradisi) or “gate of Heaven” (ianua Coeli) and other expressions alluding to her power to facilitate the eternal salvation of the faithful. In a second step, we will analyze ten sculptural and pictorial artworks that represent Mary as the gate of celestial paradise or the mediator before God in favor of believers to facilitate their eternal salvation.
Oil Theft, Energy Security and Energy Transition in Mexico
Authors: Vivoda Vlado , Krame Ghaleb , Spraggon Martin
Published: February 2023

Oil theft refers to the exploitation of crude oil or refined petroleum products for criminal purposes. In Mexico, oil theft—referred to as huachicolero—is endemic and widespread. By framing it within the energy security and transition context, this paper offers a new perspective on the problem of oil theft in Mexico. Focusing on crude oil and refined petroleum, the paper demonstrates that Mexico’s energy security—as framed around the 4As (availability, accessibility, affordability, and acceptance)—has deteriorated over the past decade. Application of the 4As framework in the Mexican context shows that the increasing frequency of oil theft has contributed to this deterioration. The proposed solution to the energy security and oil theft problems is centred on Mexico moving from gasoline and diesel to electrification in the transportation sector. The paper demonstrates that, while transport electrification in Mexico has been lagging behind other countries, recent developments in the country point to growing momentum among the country’s political and business elites, in tandem with US partners, in support for the energy transition. Areas where further emphasis should be placed to accelerate Mexico’s energy transition in the transportation sector are identified. Finally, the feasibility of and potential limitations associated with implementing the transition are evaluated.
Statistical Analysis of SF Occurrence in Middle and Low Latitudes Using Bayesian Network Automatic Identification
Authors: Feng Jian , Zhang Yuqiang , Gao Shuaihe , Wang Zhuangkai , Wang Xiang , Chen Bo , Liu Yi , Zhou Chen , Zhao Zhengyu
Published: February 2023

Spread-F (SF) is one of the most important types of the ionospheric irregularities as it causes ionospheric scintillation which can severely affect the performance and reliability of communication, navigation, and radar systems. The ionosonde provides the most effective and economical way to study the ionosphere and SF. However, the manual identification of SF from an ionogram is boring and hard work. To automatically identify SF on the ionogram and extend the study of SF into the middle and low latitudes of East Asia, this paper presents a statistical analysis of SF in this region, based on the naïve Bayesian classifier. The results showed that the accuracy of automatic identification reached up to 97% on both the validation datasets and test datasets composed of Mohe, I-Cheon, Jeju, Wuhan, and Sanya ionograms, suggesting that it is a promising way to automatically identify SF on ionograms. Based on the classification results, the statistical analysis shows that SF has a complicated morphology in the middle and low latitudes of East Asia. Specifically, there is a peak of occurrence of SF in the summer in I-Cheon, Jeju, Sanya, and Wuhan; however, the Mohe station has the highest occurrence rate of SF in December. The different seasonal variations of SF might be due to the different geographic local conditions, such as the inland-coastal differences and formation mechanism differences at these latitudes. Moreover, SF occurs more easily in the post-midnight hours when compared with the pre-midnight period in these stations, which is consistent with the previous results. Furthermore, this paper extracts the frequency SF (FSF) index and range SF (RSF) index to characterize the features of SF. The results shows that the most intense FSF/RSF appeared in the height range of 220–300 km/1–7 MHz in these stations, although there are different magnitude extensions on different season in these regions. In particular, strong spread-F (SSF) reached its maximum at the equinox at Sanya, confirming the frequent SSF occurrence at the equinox at the equator and low latitudes. These results would be helpful for understanding the characteristics of SF in East Asia.
Limited-Samples-Based Crop Classification Using a Time-Weighted Dynamic Time Warping Method, Sentinel-1 Imagery, and Google Earth Engine
Authors: Xiao Xingyuan , Jiang Linlong , Liu Yaqun , Ren Guozhen
Published: February 2023

Reliable crop type classification supports the scientific basis for food security and sustainable agricultural development. However, it still lacks a limited-samples-based crop classification method which is labor- and time-efficient. To this end, we used the Google Earth Engine (GEE) and Sentinel-1A/B SAR time series to develop eight types of crop classification strategies based on different sampling methods of central and scattered, different perspectives of object-based and pixel-based, and different classifiers of the Time-Weighted Dynamic Time Warping (TWDTW) and Random Forest (RF). We carried out 30-times classifications with different samples for each strategy to classify the crop types at the North Dakota–Minnesota border in the U.S. We then compared their classification accuracies and assessed the accuracy sensitivity to sample size. The results found that the TWDTW generally performed better than RF, especially for small-sample classification. Object-based classifications had higher accuracies than pixel-based classifications, and the object-based TWDTW had the highest accuracy. RF performed better in scattered sampling than the central sampling strategy. TWDTW performed better than RF in distinguishing soybean and dry bean with similar curves. The accuracies improved for all eight classification strategies with increasing sample size, and TWDTW was more robust, while RF was more sensitive to sample size change. RF required many more samples than TWDTW to achieve satisfactory accuracy, and it performed better than TWDTW when the sample size exceeded 50. The accuracy comparisons indicated that the TWDTW has stronger temporal and spatial generalization capabilities and has high potential applications for early, historical, and limited-samples-based crop type classification. The findings of our research are worthwhile contributions to the methodology and practices of crop type classification as well as sustainable agricultural development.
Relative Sea Level Trends for the Coastal Areas of Peninsular and East Malaysia Based on Remote and In Situ Observations
Authors: Simons Wim , Naeije Marc , Ghazali Zaki , Rahman Wan Darani , Cob Sanusi , Kadir Majid , Mustafar Asrul , Din Ami Hassan , Efendi Joni , Noppradit Prakrit
Published: February 2023

Absolute sea-level rise has become an important topic globally due to climate change. In addition, relative sea-level rise due to the vertical land motion in coastal areas can have a big societal impact. Vertical land motion (VLM) in Southeast Asia includes a tectonically induced component: uplift and subsidence in plate boundary zones where both Peninsular and East Malaysia are located. In this paper, the relative sea-level trends and (seismic cycle-induced) temporal changes across Malaysia were investigated. To do so, the data (1984–2019) from 21 tide gauges were analyzed, along with a subset (1994–2021) of nearby Malaysian GNSS stations. Changes in absolute sea level (ASL) at these locations (1992–2021) were also estimated from satellite altimetry data. As a first for Peninsular and East Malaysia, the combination ASL minus VLM was robustly used to validate relative sea-level rise from tide-gauge data and provide relative sea-level trend estimates based on a common data period of 25+ years. A good match between both the remote and in situ sea-level rise estimations was observed, especially for Peninsular Malaysia (differences < 1 mm/year), when split trends were estimated from the tide gauges and GNSS time series to distinguish between the different VLM regimes that exist due to the 2004 Sumatra–Andaman megathrust earthquake. As in the south of Thailand, post-seismic-induced negative VLM has increased relative sea-level rise by 2–3 mm/year along the Andaman Sea and Malacca Strait coastlines since 2005. For East Malaysia, the validation shows higher differences (bias of 2–3 mm/year), but this poorer match is significantly improved by either not including data after 1 January 2014 or applying a generic jump to all East Malay tide gauges from that date onwards. Overall, the present relative sea-level trends range from 4 to 6 mm/year for Malaysia with a few regions showing up to 9 mm/year due to human-induced land subsidence.
High-Accuracy Absolute-Position-Aided Code Phase Tracking Based on RTK/INS Deep Integration in Challenging Static Scenarios
Authors: Luo Yiran , Hsu Li-Ta , Jiang Yang , Liu Baoyu , Zhang Zhetao , Xiang Yan , El-Sheimy Naser
Published: February 2023

Many multi-sensor navigation systems urgently demand accurate positioning initialization from global navigation satellite systems (GNSSs) in challenging static scenarios. However, ground blockages against line-of-sight (LOS) signal reception make it difficult for GNSS users. Steering local codes in GNSS basebands is a desirable way to correct instantaneous signal phase misalignment, efficiently gathering useful signal power and increasing positioning accuracy. Inertial navigation systems (INSs) have been used as effective complementary dead reckoning (DR) sensors for GNSS receivers in kinematic scenarios, resisting various forms of interference. However, little work has focused on whether INSs can improve GNSS receivers in static scenarios. Thus, this paper proposes an enhanced navigation system deeply integrated with low-cost INS solutions and GNSS high-accuracy carrier-based positioning. First, an absolute code phase is predicted from base station information and integrated solutions of the INS DR and real-time kinematic (RTK) results through an extended Kalman filter (EKF). Then, a numerically controlled oscillator (NCO) leverages the predicted code phase to improve the alignment between instantaneous local code phases and received ones. The proposed algorithm is realized in a vector-tracking GNSS software-defined radio (SDR). Results of the time-of-arrival (TOA) and positioning based on real-world experiments demonstrated the proposed SDR.
A Preliminary Assessment of the GSMaP Version 08 Products over Indonesian Maritime Continent against Gauge Data
Authors: Ramadhan Ravidho , Marzuki Marzuki , Yusnaini Helmi , Muharsyah Robi , Tangang Fredolin , Vonnisa Mutya , Harmadi Harmadi
Published: February 2023

This study is a preliminary assessment of the latest version of the Global Satellite Measurement of Precipitation (GSMaP version 08) data, which were released in December 2021, for the Indonesian Maritime Continent (IMC), using rain gauge (RG) observations from December 2021 to June 2022. Assessments were carried out with 586 rain gauge (RG) stations using a point-to-pixel approach through continuous statistical and contingency table metrics. It was found that the coefficient correlation (CC) of GSMaP version 08 products against RG observations varied between low (CC = 0.14–0.29), moderate (CC = 0.33–0.45), and good correlation (CC = 0.72–0.75), for the hourly, daily, and monthly scales with a tendency to overestimate, indicated by a positive relative bias (RB). Even though the correlation of hourly data is still low, GSMaP can still capture diurnal patterns in the IMC, as indicated by the compatibility of the estimated peak times for the precipitation amount and frequency. GSMaP data also manage to observe heavy rainfall, as indicated by the good of detection (POD) values for daily data ranging from probability 0.71 to 0.81. Such a good POD value of daily data is followed by a relatively low false alarm ratio (FAR) (FAR < 0.5). However, the GSMaP overestimates light rainfall (R < 1 mm/day); as a consequence, it overestimates the consecutive wet days (CWD) and number of days with rainfall ≥ 1 mm (R1mm) indices, and underestimates the consecutive dry days (CDD) extreme rain index. GSMaP daily data accuracy depends on IMC’s topographic conditions, especially for GSMaP real-time data. Of all GSMaP version 08 products evaluated, outperformed post-real-time non-gauge-calibrated (GSMaP_MVK), and followed by post-real-time gauge-calibrated (GSMaP_Gauge), near-real-time gauge-calibrated (GSMaP_NRT_G), near-real-time non-gauge-calibrated (GSMaP_NRT), real-time gauge-calibrated (GSMaP_Now_G), and real-time non-gauge-calibrated (GSMaP_Now). Thus, GSMaP near-real-time data have the potential for observing rainfall in IMC with faster latency.