bluuebunny/crossref_metadata_2025 huggingface dataset:
Phenomenal Bombardment of Antibiotic in Poultry: Contemplating the Environmental Repercussions
Authors: Manikandan Muthu , Chun Sechul , Kazibwe Zakayo , Gopal Judy , Singh Udai Bhan , Oh Jae-Wook
Published: July 2020

Antibiotics have constantly been added at an unprecedented rate in order to enhance poultry meat production. Such antibiotics impose a negative impact on human health directly through meat and egg consumption. On the other hand, they also affect humans indirectly by affecting the normal key microbial processes in the agricultural environments, when used as poultry compost. For many years, farmers have been turning poultry litter into compost for agricultural use. Very few studies have addressed the fate of the unmetabolized antibiotic residues in poultry litter that could potentially affect microbial communities when used as poultry compost. We have also questioned the fate of residual antibiotic in poultry waste which may create possible negative environmental pressure on microbial communities that are involved in microbial mediated poultry litter composting processes. The incorporation of antibiotic degrading environmental isolates in poultry litter at the initial stage of composting in order to accelerate the process is addressed in this review as a future perspective.
Is It Weird to Enjoy Solitude? Relationship of Solitude Capacity with Personality Traits and Physical and Mental Health in Junior College Students
Authors: Lin Pin-Hsuan , Wang Po-Yu , Lin Ying-Lien , Yang Shang-Yu
Published: July 2020

Background: Teenagers described as enjoying their own company have been claimed to have a weird personality and experience loneliness and negative emotions and have often been labeled with negative attributes. However, previous studies have provided a limited understanding of teenagers’ capacity for solitude. Objectives: The purpose of this study was to explore the correlations between teenagers’ capacity for solitude and both personality traits and physical and mental health. Methods: This study employed a cross-sectional research design and collected data from a junior college located in Taiwan using a structured questionnaire, which consisted of demographic questions, a solitude capacity scale, a personality trait scale, and a physical and mental health scale. Results: A total of 562 participants were recruited (age = 17.56 ± 1.58 years). The total score of the solitude capacity scale was significantly correlated with four elements of the personality traits subscale: neuroticism, extraversion, openness, and conscientiousness. The solitude capacity subscale (i.e., the solitude-coping subscale) showed significant correlations with two of the physical and mental health elements, i.e., anxiety and insomnia and severe depression. Conclusions: The results verified the correlations between capacity for solitude and personality traits and did not show a positive association with negative personality traits (i.e., neuroticism). Moreover, the solitude coping capacity correlated positively with anxiety levels and negatively with depression.
Identifying the Impact of Landscape Pattern on Ecosystem Services in the Middle Reaches of the Yangtze River Urban Agglomerations, China
Authors: Liu Luwen , Chen Xingrong , Chen Wanxu , Ye Xinyue
Published: July 2020

Clarifying the impact mechanisms of landscape patterns on ecosystem services is highly important for effective ecosystem protection, policymaking, and landscape planning. However, previous literature lacks knowledge about the impact mechanisms of landscape patterns on ecosystem services from a spatial perspective. Thus, this study measured landscape patterns and the ecosystem services value (ESV) using a series of landscape pattern metrics and an improved benefit transfer method based on land-use data from 2015. It explores the impact mechanisms of the landscape pattern metrics on the ESV using the ordinary least-squares method and spatial regression models in the middle reaches of the Yangtze River Urban Agglomerations (MRYRUA), China. We found that forestland was the main landscape type in the MRYRUA, followed by cultivated land, and the fragmentation degree of cultivated land was significantly higher than that of forestland. The findings demonstrate that landscape pattern metrics had a significant impact on ecosystem services, but could vary greatly. Moreover, ecosystem services in the MRYRUA exhibited significant spatial spillover effects and cross-regional collaborative governance was an effective means of landscape planning. This paper acts as a scientific reference and effective guidance for landscape planning and regional ecosystem conservation in MRYRUA and other similarly fast-growing urban agglomerations.
Air Quality during COVID-19 in Four Megacities: Lessons and Challenges for Public Health
Authors: Connerton Patrick , Vicente de Assunção João , Maura de Miranda Regina , Dorothée Slovic Anne , José Pérez-Martínez Pedro , Ribeiro Helena
Published: July 2020

The study described in this manuscript analyzed the effects of quarantine and social distancing policies implemented due to the Coronavirus Disease 2019 (COVID-19) pandemic on air pollution levels in four western megacities: São Paulo in Brazil; Paris in France; and Los Angeles and New York in the United States. The study investigated the levels of four air pollutants—Carbon monoxide (CO), Ozone (O3), Fine Particulate (PM2.5) and Nitrogen dioxide (NO2)—during the month of March 2020, compared to 2015–2019, in the urban air of these metropolitan areas, controlling for meteorological variables. Results indicated reductions in the levels of PM2.5, CO and NO2, with reductions of the latter two showing statistical significance. In contrast, tropospheric ozone levels increased, except in Los Angeles. The beneficial health effects of cleaner air might also help prevent deaths caused by the epidemic of COVID-19 in megacities by diminishing pressure on hospitals and health equipment. Future actions for the re-starting of non-essential economic activities in these cities should take into consideration the overall importance of health for the individual, as well as for societies.
Asthma Mortality and Hospitalizations in Mexico from 2010 to 2018: Retrospective Epidemiologic Profile
Authors: Carrillo Genny , Mendez-Domínguez Nina , Datta-Banik Rudradeep , Figueroa-Lopez Fernando , Estrella-Chan Brandon , Alvarez-Baeza Alberto , Garza Norma
Published: July 2020

Acute respiratory infections have been established as the principal cause of disease in the Mexican population from 2000 to 2018; however, even when these diseases may aggravate asthma, there is a lack of epidemiologic evidence on the health outcomes when both conditions coexist. Learning about the asthma hospitalizations trends will help us identify monthly variation of hospitalizations, vulnerable groups, needed services, and improvements in therapeutics and prevention. This study aims to analyze the variation in asthma hospitalizations and mortality during the 2010–2018 period in Mexico. Data were obtained from the General Board of Health Information (DGIS) Open Access datasets, which were analyzed taking hospital discharges and hospital deaths recorded from 2010 to 2018 from all public hospitals nationwide. The binomial logistic regression analyses were performed to determine the association between patient ages, hospitalization month, and mortality. The death rate from asthma in Mexico decreased between 2010 and 2018. Still, the hospital mortality rate shows recent improvement; however, prognosis of hospitalized patients depends on their age, accurate diagnosis, length of hospital stay and occurrence of nosocomial infection.
Trade Impacts on Embodied Carbon Emissions—Evidence from the Bilateral Trade between China and Germany
Authors: Li Jiajia , Chandio Abbas Ali , Liu Yucong
Published: July 2020

This article attempts to investigate the impacts of bilateral trade on the environment by estimating the embodied carbon emissions between China and Germany over the period 1999–2018. The above impacts are broadly explored in the literature both under the framework of theoretical and empirical analysis. However, there exist fewer empirical studies exploring the nonlinear relationship between trade volumes and carbon emissions between a well-developed and emerging economies. By applying the multiregional input-output (MRIO) model, this article aims to reveal the impacts of trade on the environment in the case of China–Germany. Specifically, trade amounts between China and Germany rank high with a similarly increasing trend and both of them are large net exporting countries. However, China experienced much larger carbon emissions embodied in its exports to Germany. Despite potential concerns on the carbon leakage issue of China from Germany, we find that the bilateral trades fit an inverse U-shape in the embodied carbon emissions, which suggests that the trade between the two countries can finally reduce carbon intensity without obstructing economic development particularly in the long-term. This paper guides policy-makers to quantify the issue of CO2 transfer among bilateral trades in order to achieve the target of trading sustainability.
Digital Surveillance for Monitoring Environmental Health Threats: A Case Study Capturing Public Opinion from Twitter about the 2019 Chennai Water Crisis
Authors: Xiong Jiangmei , Hswen Yulin , Naslund John A.
Published: July 2020

Globally, water scarcity has become a common challenge across many regions. Digital surveillance holds promise for monitoring environmental threats to population health due to severe drought. The 2019 Chennai water crisis in India resulted in severe disruptions to social order and daily life, with local residents suffering due to water shortages. This case study explored public opinion captured through the Twitter social media platform, and whether this information could help local governments with emergency response. Sentiment analysis and topic modeling were used to explore public opinion through Twitter during the 2019 Chennai water crisis. The latent Dirichlet allocation (LDA) method identified topics that were most frequently discussed. A naïve Tweet classification method was built, and Twitter posts (called tweets) were allocated to identified topics. Topics were ranked, and corresponding emotions were calculated. A cross-correlation was performed to examine the relationship between online posts about the water crisis and actual rainfall, determined by precipitation levels. During the Chennai water crisis, Twitter users posted content that appeared to show anxiety about the impact of the drought, and also expressed concerns about the government response. Twitter users also mentioned causes for the drought and potential sustainable solutions, which appeared to be mainly positive in tone. Discussion on Twitter can reflect popular public opinion related to emerging environmental health threats. Twitter posts appear viable for informing crisis management as real-time data can be collected and analyzed. Governments and public health officials should adjust their policies and public communication by leveraging online data sources, which could inform disaster prevention measures.
Effects of Health Information Dissemination on User Follows and Likes during COVID-19 Outbreak in China: Data and Content Analysis
Authors: Ma Rongyang , Deng Zhaohua , Wu Manli
Published: July 2020

Background: COVID-19 has greatly attacked China, spreading in the whole world. Articles were posted on many official WeChat accounts to transmit health information about this pandemic. The public also sought related information via social media more frequently. However, little is known about what kinds of information satisfy them better. This study aimed to explore the characteristics of health information dissemination that affected users’ information behavior on WeChat. Methods: Two-wave data were collected from the top 200 WeChat official accounts on the Xigua website. The data included the change in the number of followers and the total number of likes on each account in a 7-day period, as well as the number of each type of article and headlines about coronavirus. It was used to developed regression models and conduct content analysis to figure out information characteristics in quantity and content. Results: For nonmedical institution accounts in the model, report and story types of articles had positive effects on users’ following behaviors. The number of headlines on coronavirus positively impacts liking behaviors. For medical institution accounts, report and science types had a positive effect, too. In the content analysis, several common characteristics were identified. Conclusions: Characteristics in terms of the quantity and content in health information dissemination contribute to users’ information behavior. In terms of the content in the headlines, via coding and word frequency analysis, organizational structure, multimedia applications, and instructions—the common dimension in different articles—composed the common features in information that impacted users’ liking behaviors.
Peripheral Dopamine 2-Receptor Antagonist Reverses Hypertension in a Chronic Intermittent Hypoxia Rat Model
Authors: Olea Elena , Docio Inmaculada , Quintero Miguel , Rocher Asunción , Obeso Ana , Rigual Ricardo , Gomez-Niño Angela
Published: July 2020

The sleep apnea-hypopnea syndrome (SAHS) involves periods of intermittent hypoxia, experimentally reproduced by exposing animal models to oscillatory PO2 patterns. In both situations, chronic intermittent hypoxia (CIH) exposure produces carotid body (CB) hyperactivation generating an increased input to the brainstem which originates sympathetic hyperactivity, followed by hypertension that is abolished by CB denervation. CB has dopamine (DA) receptors in chemoreceptor cells acting as DA-2 autoreceptors. The aim was to check if blocking DA-2 receptors could decrease the CB hypersensitivity produced by CIH, minimizing CIH-related effects. Domperidone (DOM), a selective peripheral DA-2 receptor antagonist that does not cross the blood-brain barrier, was used to examine its effect on CIH (30 days) exposed rats. Arterial pressure, CB secretory activity and whole-body plethysmography were measured. DOM, acute or chronically administered during the last 15 days of CIH, reversed the hypertension produced by CIH, an analogous effect to that obtained with CB denervation. DOM marginally decreased blood pressure in control animals and did not affect hypoxic ventilatory response in control or CIH animals. No adverse effects were observed. DOM, used as gastrokinetic and antiemetic drug, could be a therapeutic opportunity for hypertension in SAHS patients’ resistant to standard treatments.
Allosterism of Nicotinic Acetylcholine Receptors: Therapeutic Potential for Neuroinflammation Underlying Brain Trauma and Degenerative Disorders
Authors: Mitra Swarup , Khatri Shailesh N. , Maulik Malabika , Bult-Ito Abel , Schulte Marvin
Published: July 2020

Inflammation is a key physiological phenomenon that can be pervasive when dysregulated. Persistent chronic inflammation precedes several pathophysiological conditions forming one of the critical cellular homeostatic checkpoints. With a steady global surge in inflammatory diseases, it is imperative to delineate underlying mechanisms and design suitable drug molecules targeting the cellular partners that mediate and regulate inflammation. Nicotinic acetylcholine receptors have a confirmed role in influencing inflammatory pathways and have been a subject of scientific scrutiny underlying drug development in recent years. Drugs designed to target allosteric sites on the nicotinic acetylcholine receptors present a unique opportunity to unravel the role of the cholinergic system in regulating and restoring inflammatory homeostasis. Such a therapeutic approach holds promise in treating several inflammatory conditions and diseases with inflammation as an underlying pathology. Here, we briefly describe the potential of cholinergic allosterism and some allosteric modulators as a promising therapeutic option for the treatment of neuroinflammation.
Design and Execution of Integrated Clinical Pathway: A Simplified Meta-Model and Associated Methodology
Authors: Ardito Carmelo , Caivano Danilo , Colizzi Lucio , Dimauro Giovanni , Verardi Loredana
Published: July 2020

Integrated clinical pathways (ICPs) are task-oriented care plans detailing the essential steps of the therapeutic pathway referring to a specific clinical problem with a patient’s expected clinical course. ICPs represent an effective tool for resource management in the public and private health domains. To be automatically executed, the ICP process has to be described by means of complex general purpose description language (GPDL) formalisms. However, GPDLs make the process model difficult to grasp by a human. On the other hand, the adoption of a reduced set of graphical constructs prevents a fully automated process execution due to the lack of information required by a machine. Unfortunately, it is difficult to find a balance between modelling language expressiveness and the automated execution of the modelled processes. In this paper, we present a meta-model based on a GPDL to organize the ICP process knowledge. This meta-model allows the management of ICP information in a way that is independent from the graphic representation of the adopted modelling standard. We also propose a general framework and a methodology that aim to guarantee a high degree of automation in process execution. In particular, the corresponding execution engine is implemented as a chatbot (integrated with social media), which plays a two-fold role: during the actual execution of the entire ICP, it acts as a virtual assistant and gathers the patient’s health data. Tests performed on a real ICP showed that, thanks to the proposed solution, the chatbot engine is able to engage in a dialogue with the patient. We provide discussion about how the system could be extended and how it could be seen as an alternative to Artificial Intelligence (AI) and Natural Language Processing (NLP)-based approaches.
On Landscape Architecture Education and Professional Practice and Their Future Challenges
Authors: Steinitz Carl
Published: July 2020

Increased environmental and social risk, ubiquitous information technology, and growing demands for and growing threats to democracy and public participation will alter the education and practice of all the design professions and the geographically oriented sciences, and the ways in which their activities towards influencing environmental and social change are organized and carried out. We all know about these trends, but we do not take them seriously enough. We are not adapting fast enough towards education or professional practice that is collaborative and globally oriented.
The Effect of Surface Morphology of Tapered Rolling Bearings in High-Speed Train on Grease Lubrication
Authors: Wang Heli , Huang Haifeng , Yu Sibo , Gu Weijie
Published: July 2020

With the extensive coverage of the rail transit system, ensuring the safe operation of rail vehicles is an important prerequisite. Insufficient lubrication will cause friction and wear of axle box bearings, which is directly related to ensured safety of high-speed trains. A non-Newtonian elastohydrodynamic lubrication(EHL) between tapered rolling elements and inner ring of axle box bearing in high-speed trains was established by numeric simulation. The input parameters of working conditions, including velocity, acceleration and plastic viscosity, were changed, considering the actual application and their influence trends on film-forming characteristics were analyzed. As a result, a phase of acceleration of starting or a process of braking at a low speed tends to occur mixed lubrication. Therefore, a method of optimizing surface morphology of rolling elements was adopted to improve lubrication. Based on comparison experiments, it was recommended that RMS roughness was greater than 0.03 μm and less than 0.1 μm and kurtosis was three and skewness was negative in a range of −1 to −0.5 and texture direction was parallel to rotation direction. The optimized surface promotes the transition from mixed-lubrication to full film lubrication, which alleviated the problem of surface damage due to insufficient lubrication and prolongated the service life.
Hydraulic and Mechanical Impacts of Pore Space Alterations within a Sandstone Quantified by a Flow Velocity-Dependent Precipitation Approach
Authors: Wetzel Maria , Kempka Thomas , Kühn Michael
Published: July 2020

Geochemical processes change the microstructure of rocks and thereby affect their physical behaviour at the macro scale. A micro-computer tomography (micro-CT) scan of a typical reservoir sandstone is used to numerically examine the impact of three spatial alteration patterns on pore morphology, permeability and elastic moduli by correlating precipitation with the local flow velocity magnitude. The results demonstrate that the location of mineral growth strongly affects the permeability decrease with variations by up to four orders in magnitude. Precipitation in regions of high flow velocities is characterised by a predominant clogging of pore throats and a drastic permeability reduction, which can be roughly described by the power law relation with an exponent of 20. A continuous alteration of the pore structure by uniform mineral growth reduces the permeability comparable to the power law with an exponent of four or the Kozeny–Carman relation. Preferential precipitation in regions of low flow velocities predominantly affects smaller throats and pores with a minor impact on the flow regime, where the permeability decrease is considerably below that calculated by the power law with an exponent of two. Despite their complete distinctive impact on hydraulics, the spatial precipitation patterns only slightly affect the increase in elastic rock properties with differences by up to 6.3% between the investigated scenarios. Hence, an adequate characterisation of the spatial precipitation pattern is crucial to quantify changes in hydraulic rock properties, whereas the present study shows that its impact on elastic rock parameters is limited. The calculated relations between porosity and permeability, as well as elastic moduli can be applied for upscaling micro-scale findings to reservoir-scale models to improve their predictive capabilities, what is of paramount importance for a sustainable utilisation of the geological subsurface.
A Temperature-Dependent Model of Shape Memory Alloys Considering Tensile-Compressive Asymmetry and the Ratcheting Effect
Authors: Wang Longfei , Feng Peihua , Wu Ying , Liu Zishun
Published: July 2020

Tensile-compressive asymmetry and the ratcheting effect are two significant characteristics of shape memory alloys (SMAs) during uniaxial cyclic tests, thus having received substantial attention in research. In this study, by redefining the internal variables in SMAs by considering the cyclic accumulation of residual martensite, we propose a constitutive model for SMAs to simultaneously reflect tensile-compressive asymmetry and the cyclic ratcheting effect under multiple cyclic tests. This constitutive model is temperature dependent and can be used to reasonably capture the typical features of SMAs during tensile-compressive cyclic tests, which include the pseudo-elasticity at higher temperatures as well as the shape-memory effect at lower temperatures. Moreover, the proposed model can predict the cyclic mechanical behavior of SMAs subjected to applied stresses with different peak and valley values under tension and compression. Agreement between the predictions obtained from the proposed model and the published experimental data is observed, which confirms that the proposed novel constitutive model of SMAs is feasible.
Experimental Investigation of Reinforced Concrete Beam with Openings Strengthened Using FRP Sheets under Cyclic Load
Authors: Salih Rania , Zhou Fangyuan , Abbas Nadeem , Khan Mastoi Aamir
Published: July 2020

In this study, the cyclic behavior of reinforced concrete (RC) beam with openings strengthened using carbon fiber-reinforced polymers (FRPs) was experimentally investigated. Seven rectangular RC beams were cast and strengthened through external bonding of carbon fiber-reinforced polymer (CFRP) sheets around the beam web opening with different orientations to evaluate the maximum resistance, secant stiffness, strength degradation, ductility, energy dissipation capacity and behavior of the specimens’ failure mode under cyclic load. One solid beam without an opening (i.e., control specimen) and six beams constructed with circular web openings typically located in the middle of the beam and adjacent to the supports were used in the experiments. Among the six specimens with opening configuration, two beams were unstrengthened, and the remaining four specimens were strengthened with two layers of FRP sheets with vertical and inclined scheme orientation. Numerical studies were performed on ABAQUS software, and finite element modelling analysis results were verified through experiments. Results demonstrated that the use of FRP sheets has a significant effect on the cyclic behavior of RC beams, thereby improving the maximum strength and ultimate displacement to approximately 66.67% and 77.14%, respectively. The validated finite element models serve as a numerical platform to apply beneficial parametric studies, where the effects of opening size and bond length are investigated.
Building of Longitudinal Ultrasonic Assisted Turning System and Its Cutting Simulation Study on Bulk Metallic Glass
Authors: Shan Shuo , Feng Pingfa , Zha Huiting , Feng Feng
Published: July 2020

Bulk metallic glass (BMG) is a new kind of material which is made by rapid condensation of alloy. With excellent properties like high strength, high hardness, corrosion resistance, BMG is increasingly applied in mold manufacturing, weapon equipment and other fields. However, BMG is also one of hard-to-machine materials, which is arduous to be processed precisely and efficiently by the means of conventional cutting. Compared with conventional cutting, ultrasonic machining has a multitude of technological advantages such as reducing the cutting force, extending the tool life, etc. In ultrasonic machining, the ultrasonic electric signal is transformed into high frequency mechanical vibration on the tool, which changes the relationship between the tool and the workpiece in the process of machining. In this study, the longitudinal ultrasonic assisted turning (LUAT) system is established for processing BMG. Its resonant frequency and vibration characteristics are first simulated by modal analysis and harmonic response analysis, and then tested by displacement testing experiments, so that the suitable frequency and the amplitude for BMG turning can be selected and verified. On this basis, the two-dimensional turning finite element model is established to study the effect of ultrasonic vibration on cutting force under different cutting speeds. The research manifest that during the BMG turning, the assistance of longitudinal ultrasonic vibration can significantly reduce the average cutting force as well as the von Mises stress when the turning speed is below the critical turning speed. In addition, the tip of the tool contacts the workpiece discontinuously during cutting process which makes the instantaneous turning force in LUAT more periodic than that in conventional turning (CT).
Experimental Investigation and ANFIS-Based Modelling During Machining of EN31 Alloy Steel
Authors: Shivakoti Ishwer , Rodrigues Lewlyn L. R. , Cep Robert , Pradhan Premendra Mani , Sharma Ashis , Kumar Bhoi Akash
Published: July 2020

This research presents the parametric effect of machining control variables while turning EN31 alloy steel with a Chemical Vapor deposited (CVD) Ti(C,N) + Al2O3 + TiN coated carbide tool insert. Three machining parameters with four levels considered in this research are feed, revolutions per minute (RPM), and depth of cut (ap). The influences of those three factors on material removal rate (MRR), surface roughness (Ra), and cutting force (Fc) were of specific interest in this research. The results showed that turning control variables has a substantial influence on the process responses. Furthermore, the paper demonstrates an adaptive neuro fuzzy inference system (ANFIS) model to predict the process response at various parametric combinations. It was observed that the ANFIS model used for prediction was accurate in predicting the process response at varying parametric combinations. The proposed model presents correlation coefficients of 0.99, 0.98, and 0.964 for MRR, Ra, and Fc, respectively.
Electrical, Dielectric Property and Electrochemical Performances of Plasticized Silver Ion-Conducting Chitosan-Based Polymer Nanocomposites
Authors: M. Hadi Jihad , B. Aziz Shujahadeen , M. Nofal Muaffaq , Hussein Sarkawt A. , Hafiz Muhamad H. , Brza Mohamad A. , Abdulwahid Rebar T. , Kadir Mohd F. Z. , Woo Haw J.
Published: July 2020

In the present work, chitosan (CS) as a natural biopolymer was used to prepare nanocomposite polymer electrolytes (NCPEs) in order to reduce plastic waste pollution. The plasticized CS-based NCSPE has been prepared via the solution casting technique. The electrical properties of the films were investigated using AC conductivity, dielectric properties, electric modulus, and electrical impedance spectroscopy (EIS). The obtained results from the dielectric properties and electric modulus study confirm the non-Debye behavior of ion dynamics. The effect of glycerol plasticizer on ionic conductivity of the CS:AgNO3:Al2O3 system was investigated via AC conductivity and impedance studies. The conductivity of the samples was explained based on electrical equivalent circuits and Bode plots. The electrochemical properties such as transfer number measurement (TNM), linear sweep voltammetry (LSV), and cyclic voltammetry (CV) were carried out to inspect the sample suitability for electrochemical double-layer capacitor (EDLC) application. The highest conductivity was 3.7 × 10−4 S cm−1 with the electrochemical stability window up to 2.1 V at room temperature. Through the TNM study, the ionic conductivity of plasticized CS-based NCSPE was confirmed, and ion transport (tion) of the highest conducting sample was found to be 0.985. The activated carbon electrode with the highest conducting sample was employed in the EDLC device fabrication. Accordingly, it can be said that the highest conducting sample had capable performance to be applied in electrochemical device application.
Effect of Backing Plate Materials in Micro-Friction Stir Butt Welding of Dissimilar AA6061-T6 and AA5052-H32 Aluminum Alloys
Authors: Park SeongHwan , Joo YoungHwan , Kang Myungchang
Published: July 2020

Thin sheets of lightweight aluminum alloys, which are increasingly used in automotive, aerospace, and electronics industries to reduce the weight of parts, are difficult to weld. When applying micro-friction stir welding (μ-FSW) to thin plates, the heat input to the base materials is considerably important to counter the heat loss to the jig and/or backing plate. In this study, three different backing-plate materials—cordierite ceramic, titanium alloy, and copper alloy—were used to evaluate the effect of heat loss on weldability in the μ-FSW process. One millimeter thick AA6061-T6 and AA5052-H32 dissimilar aluminum alloy plates were micro-friction stir welded by a butt joint. The tensile test, hardness, and microstructure of the welded joints using a tool rotational speed of 9000 rpm, a welding speed of 300 mm/min, and a tool tilting angle of 0° were evaluated. The heat loss was highly dependent on the thermal conductivity of the backing plate material, resulting in variations in the tensile strength and hardness distribution of the joints prepared using different backing plates. Consequently, the cordierite backing plate exhibited the highest tensile strength of 222.63 MPa and an elongation of 10.37%, corresponding to 86.7% and 58.4%, respectively, of those of the AA5052-H32 base metal.
Initial Deformation Behaviors in Lean Duplex Stainless Steel
Authors: Kim Rosa , Bae Cheoljun , Kim Jongryoul
Published: July 2020

The deformation behaviors of the austenite phase in lean duplex stainless steels were investigated through uniaxial tension tests with different amounts of deformation. Microstructural analysis showed that in the initial deformation stage the deformation in austenite grains had a predominant effect on the strain hardening behavior of the LDX-2101 steel. The initial deformation in the austenite grains was found to be mainly accommodated by the formation of stacking faults. As the deformation increased further, mechanical twins were generated by the initial stacking faults and sequentially interacted with dislocations to accommodate the strain. The analysis of dislocation behavior revealed that the deformation twinning process followed the three-layer twin formation mechanism.
Analysis of Tribological Properties in Disks of AA-5754 and AA-5083 Aluminium Alloys Previously Processed by Equal Channel Angular Pressing and Isothermally Forged
Authors: Luis Pérez Carmelo J. , Luri Irigoyen Rodrigo , Puertas Arbizu Ignacio , Salcedo Pérez Daniel , León Iriarte Javier , Fuertes Bonel Juan P.
Published: July 2020

In the present study, the wear behaviour of two aluminium alloys (AA-5754 and AA-5083) is analysed where these have been previously processed by severe plastic deformation (SPD) with equal channel angular pressing (ECAP). In order to achieve the objectives of this study, several disks made of these alloys are manufactured by isothermal forging from different initial states. The microstructures of the initial materials analysed in this study have different accumulated deformation levels. In order to compare the properties of the nanostructured materials with those which have not been ECAP-processed, several disks with a height of 6 mm and a diameter of 35 mm are manufactured from both aluminium alloys (that is, AA-5754 and AA-5083) isothermally forged at temperatures of 150 and 200 °C, respectively. These thus-manufactured disks are tested under a load of 0.6 kN, which is equivalent to a stress mean value of 18 MPa, and at a rotational speed of 200 rpm. In order to determine the wear values, the disks are weighed at the beginning, at 10,000 revolutions, at 50,000 revolutions and at 100,000 revolutions, and then the volume-loss values are calculated. This study was carried out using specific equipment, which may be considered to have a block-on-ring configuration, developed for testing in-service wear behaviour of mechanical components. From this, the wear coefficients for the two materials at different initial states are obtained. In addition, a comparison is made between the behaviour of the previously ECAP-processed aluminium alloys and those that are non-ECAP-processed. A methodology is proposed to determine wear coefficients for the aluminium alloys under consideration, which may be used to predict the wear behaviour. It is demonstrated that AA-5754 and AA-5083 aluminium alloys improve wear behaviour after the ECAP process compared to that obtained in non-ECAP-processed materials.
Low Temperature Sealing Process and Properties of Kovar Alloy to DM305 Electronic Glass
Authors: Wang Zhenjiang , Gao Zeng , Chu Junlong , Qiu Dechao , Niu Jitai
Published: July 2020

The low temperature sealing of Kovar alloy to DM305 electronic glass was realized by using lead-free glass solder of the Bi2O3-ZnO-B2O3 system in atmospheric environment. The sealing process was optimized by pre-oxidation of Kovar alloy and low temperature founding of flake glass solder. The effects of sealing temperature and holding time on the properties of sealing joint were studied by means of X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), etc. The results showed that the pre-oxidized Kovar alloy and DM305 electronic glass were successfully sealed with flake glass solder at the sealing temperature of 500 °C for 20 min. Meanwhile, the joint interface had no pores, cracks, and other defects, the shear strength was 12.24 MPa, and the leakage rate of air tightness was 8 × 10−9 Pa·m3/s. During the sealing process, element Bi in glass solder diffused into the oxide layer of Kovar alloy and DM305 electronic glass about 1 μm, respectively.
Electrochemical Migration Inhibition of Tin by Disodium Hydrogen Phosphate in Water Drop Test
Authors: Liao Bokai , Wang Hong , Wan Shan , Xiao Weiping , Guo Xingpeng
Published: July 2020

The inhibition effect of Na2HPO4 on the electrochemical migration (ECM) of pure tin was investigated by means of water drop testing and surface characterizations. The effects of concentration of Na2HPO4 and applied direct current (DC) bias voltage on the ECM were also studied. Results showed that the mean time to failure caused by ECM decreased with the increasing bias voltage. Upon addition of relative high concentrations of Na2HPO4, Na2HPO4 can react with metallic tin or tin ions to form a protective film on the surface of anode and increase the pitting potential. The rate of anodic dissolution can be slowed down and thus ECM of tin was retarded. Fractal-like dendrites formed after ECM tests in the absence and presence of low concentrations of Na2HPO4 mainly consisted of tin elements. Relevant reactions were proposed to explain the inhibitory effect of Na2HPO4 on the ECM of tin.
Computational Fatigue Analysis of Auxetic Cellular Structures Made of SLM AlSi10Mg Alloy
Authors: Ulbin Miran , Borovinšek Matej , Vesenjak Matej , Glodež Srečko
Published: July 2020

In this study, a computational fatigue analysis of topology optimised auxetic cellular structures made of Selective Laser Melting (SLM) AlSi10Mg alloy is presented. Structures were selected from the Pareto front obtained by the multi-objective optimisation. Five structures with different negative Poisson’s ratios were considered for the parametric numerical analysis, where the fillet radius of cellular struts has been chosen as a parameter. The fatigue life of the analysed structures was determined by the strain–life approach using the Universal Slope method, where the needed material parameters were determined according to the experimental results obtained by quasi-static unidirectional tensile tests. The obtained computational results have shown that generally less auxetic structures tend to have a better fatigue life expectancy. Furthermore, the fillet radius has a significant impact on fatigue life. In general, the fatigue life decreases for smaller fillet radiuses (less than 0.3 mm) as a consequence of the high-stress concentrations, and also for larger fillet radiuses (more than 0.6 mm) due to the moving of the plastic zone away from the edge of the cell connections. The obtained computational results serve as a basis for further investigation, which should be focused on the experimental testing of the fabricated auxetic cellular structures made of SLM AlSi10Mg alloy under cyclic loading conditions.
Study of Micro Structural Material Changes after WEDM Based on TEM Lamella Analysis
Authors: Mouralova Katerina , Zahradnicek Radim , Benes Libor , Prokes Tomas , Hrdy Radim , Fries Jiri
Published: July 2020

Wire electrical discharge machining is an unconventional machining technology that is crucial in many industries. The surface quality of the machined parts is carefully monitored, but the condition of the subsurface layer also plays a crucial role, especially in case of defects occurrence such as cracks or burnt cavities. The subsurface layer of individual materials is affected differently due to wire electrical discharge machining. For this reason, this study was carried out focusing on a detailed analysis of transmission electron microscope (TEM) lamella made of Ti-6Al-4V titanium alloy, AlZn6Mg2Cu aluminum alloy, pure molybdenum, Creusabro 4800 steel, and Hardox 400 steel. The attention was first of all paid to the concentration and distribution of individual elements in the recast layer and also in the base material, which was often affected by wire electrical discharge machining. Further, a diffraction analysis was performed for each TEM lamella in the adhesive area and in the base material area. In order to assess the macro-effects on the machined material, the topography analysis of the machined surfaces and the morphology analysis were performed using electron microscopy.
The Pentose Phosphate Pathway Dynamics in Cancer and Its Dependency on Intracellular pH
Authors: Alfarouk Khalid O. , Ahmed Samrein B. M. , Elliott Robert L. , Benoit Amanda , Alqahtani Saad S. , Ibrahim Muntaser E. , Bashir Adil H. H. , Alhoufie Sari T. S. , Elhassan Gamal O. , Wales Christian C. , Schwartz Laurent H. , Ali Heyam S. , Ahmed Ahmed , Forde Patrick F. , Devesa Jesus , Cardone Rosa A. , Fais Stefano , Harguindey Salvador , Reshkin Stephan J.
Published: July 2020

The Pentose Phosphate Pathway (PPP) is one of the key metabolic pathways occurring in living cells to produce energy and maintain cellular homeostasis. Cancer cells have higher cytoplasmic utilization of glucose (glycolysis), even in the presence of oxygen; this is known as the “Warburg Effect”. However, cytoplasmic glucose utilization can also occur in cancer through the PPP. This pathway contributes to cancer cells by operating in many different ways: (i) as a defense mechanism via the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) to prevent apoptosis, (ii) as a provision for the maintenance of energy by intermediate glycolysis, (iii) by increasing genomic material to the cellular pool of nucleic acid bases, (iv) by promoting survival through increasing glycolysis, and so increasing acid production, and (v) by inducing cellular proliferation by the synthesis of nucleic acid, fatty acid, and amino acid. Each step of the PPP can be upregulated in some types of cancer but not in others. An interesting aspect of this metabolic pathway is the shared regulation of the glycolytic and PPP pathways by intracellular pH (pHi). Indeed, as with glycolysis, the optimum activity of the enzymes driving the PPP occurs at an alkaline pHi, which is compatible with the cytoplasmic pH of cancer cells. Here, we outline each step of the PPP and discuss its possible correlation with cancer.
Ethyl Pyruvate Increases Post-Ischemic Levels of Mitochondrial Energy Metabolites: A 13C-Labeled Cerebral Microdialysis Study
Authors: Nygaard Kevin H. , Havelund Jesper F. , Nielsen Troels H. , Nordström Carl-Henrik , Færgeman Nils. J. , Poulsen Frantz R. , Gramsbergen Jan Bert , Forsse Axel
Published: July 2020

Mitochondrial dysfunction after transient cerebral ischemia can be monitored by cerebral microdialysis (CMD) using changes in the lactate and pyruvate concentrations and ratio. Other metabolites associated with mitochondrial (dys)function are, e.g., tricyclic acid (TCA) and purine metabolites. Ethyl pyruvate (EP) is a putative neuroprotectant, supposedly targeting mitochondrial energy metabolism, but its effect on cerebral energy metabolism has never been described using microdialysis. In this study we monitored the metabolic effects of EP in the endothelin-1 (ET-1) rat model using perfusion with 13C-succinate and analysis of endogenous and 13C-labeled metabolites in the dialysates by liquid chromatography-mass spectrometry (LC-MS). Adult Sprague Dawley rats (n = 27 of which n = 11 were included in the study) were subjected to the microdialysis experiments. Microdialysis probes were perfused with 13C-labeled succinate (1 mM), and striatal dialysates were collected at 30 min intervals before induction of the insult, during intracerebral application of ET-1, and during intravenous treatment with either EP (40 mg/kg) or placebo, which was administered immediately after the insult. The rats were subjected to transient cerebral ischemia by unilateral microinjection of ET-1 in the piriform cortex, causing vasoconstriction of the medial cerebral artery. Monitoring was continued for 5 h after reperfusion, and levels of endogenous and 13C-labeled energy metabolites before and after ischemia-reperfusion were compared in EP-treated and control groups. Infarct volumes were assessed after 24 h. In both the EP-treated and placebo groups, ET-1-induced vasoconstriction resulted in a transient depression of interstitial glucose and elevation of lactate in the ipsilateral striatum. In the reperfusion phase, the concentrations of labeled malate, isocitrate, and lactate as well as endogenous xanthine were significantly higher in the EP-group than in the placebo-group: (mean ± SEM) labeled malate: 39.5% ± 14.9, p = 0.008; labeled isocitrate: 134.8% ± 67.9, p = 0.047; labeled lactate: 61% ± 22.0, p = 0.007; and endogenous xanthine: 93.9% ± 28.3, p = 0.0009. In the placebo group, significantly elevated levels of uridine were observed (mean ± SEM) 32.5% ± 12.7, p = 0.01. Infarct volumes were not significantly different between EP-treated and placebo groups, p = 0.4679. CMD labeled with 13C-succinate enabled detection of ischemic induction and EP treatment effects in the ET-1 rat model of transient focal cerebral ischemia. EP administered as a single intravenous bolus in the reperfusion-phase after transient cerebral ischemia increased de novo synthesis of several key intermediate energy metabolites (13C-malate, 13C-isocitrate, and endogenous xanthine). In summary, mitochondria process 13C-succinate more effectively after EP treatment.
Editorial of Special Issue “Piezoelectric Transducers: Materials, Devices and Applications”
Authors: Sanchez-Rojas Jose Luis
Published: July 2020

Advances in miniaturization of sensors, actuators, and smart systems are receiving substantial industrial attention, and a wide variety of transducers are commercially available or possess high potential to impact emerging markets [...]
Photoacoustic Detection of H2 and NH3 Using Plasmonic Signal Enhancement in GaN Microcantilevers
Authors: Khan Digangana , Li Hongmei , Bayram Ferhat , Gajula Durga , Koley Goutam
Published: July 2020

Photoacoustic (PA) detection of H2 and NH3 using plasmonic excitation in Pt- and Pd-decorated GaN piezotransistive microcantilevers were investigated using pulsed 520-nm laser illumination. The sensing performances of 1-nm Pt and Pd nanoparticle (NP) deposited cantilever devices were compared, of which the Pd-coated sensor devices exhibited consistently better sensing performance, with lower limit of detection and superior signal-to-noise ratio (SNR) values, compared to the Pt-coated devices. Among the two functionalization layers, Pd-coated devices were found to respond only to H2 exposure and not to NH3, while Pt-coated devices exhibited repeatable response to both H2 and NH3 exposures, highlighting the potential of the former in performing selective detection between these reducing gases. Optimization of the device-biasing conditions were found to enhance the detection sensitivity of the sensors.
Scattering of Ultrashort X-ray Pulses by Various Nanosystems
Authors: Eseev Marat , Goshev Andrey , Makarov Dmitry
Published: July 2020

Currently, the study of the scattering of ultrashort X-ray pulses (USPs) by various objects is an urgent task, in connection with the creation of powerful sources of USP generation. In this paper, the theory of the scattering of attosecond pulses by polyatomic structures is developed taking into account the magnetic component of USPs. It is shown that the scattering spectra depend not only on the structure of the target, but also on other characteristics of USPs. Results are presented of the calculation of the scattering spectra on various nanosystems, such as rings, groups of rings, carbon nanotubes (CNTs), and groups of co-directed CNTs (forest CNTs). The calculation results are presented in an analytical form, which allows a general analysis of the expressions. It was found that taking the magnetic component of the momentum into the scattering spectra into account leads to the generation of the second harmonic. In this case, the spectra have characteristic features and differ from the scattering spectra at the carrier frequency, which can complement ultra-high-resolution X-ray analysis. It is shown that the scattering spectra of some structures, for example, forest CNTs, have a strictly specified radiation direction and such material in the field of such USPs is non-reflective (completely black).