bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal controlled islanding considering frequency‐arresting and frequency‐stabilising constraints: A graph theory‐assisted approach
Authors: Daniar Sabah , Aminifar Farrokh , Hesamzadeh Mohammad Reza , Lesani Hamid
Published: March 2021

The optimal controlled islanding of power systems is a practical solution to prevent system blackouts if the boundary of islands and corrective control actions in each island are carefully specified. This paper establishes a model for the controlled islanding problem by a proposed mixed integer linear program (MILP). The frequency‐arresting (FA) and frequency‐stabilising (FS) constraints are linearised and incorporated in our FA‐FS‐constrained MILP model to prevent triggering of load shedding (LS) relays. This achievement makes our model capable of handling low‐inertia networks. Intentional LS and stepwise generation curtailment are corrective actions accommodated for frequency control and power mismatch considerations. These corrective actions increase the degree of freedom and broaden the feasible space of the MILP model under the envisaged tough operating conditions. Our model's computational efficiency is improved using a proposed graph theory‐based network reduction technique. The basic groups of coherent generators, determined in the offline mode, are aggregated as equivalent buses using an extended Steiner tree method. A graph‐path determination technique is also proposed to generate disconnection constraints (between equivalent buses of incoherent areas) and bus‐allocation constraints. Simulation results on the IEEE 39‐bus test system and a 76‐bus case study verify the proposed network reduction technique's effectiveness and the MILP model.
Assessment of the impacts of distributed generation and electric vehicles as mobile sources through a nodal and zonal pricing methodology
Authors: dos Santos Priscila Duarte , de Souza Antonio Carlos Zambroni , Bonatto Benedito Donizeti
Published: March 2021

Electricity is an essential asset for the economic and social development of any region. In the search for a cleaner, balanced and economical process, the industry and the electricity sector suffered several transformations over the years. Renewable energies became appealing, but electric vehicles also deserve attention, especially because they can act as source or load, with an impact on the electricity tariff. This work uses nodal and zonal pricing methodologies in a distribution system to verify the renewable micro‐generation advantage to the system and to scale them through an electricity tariff system, based on a regulatory context implemented in Brazil. The used methodology enables one to assess how the distributed generators, including electric vehicles working as sources, interfere with the locational pricing in the system.
COVID‐19 disease severity assessment using CNN model
Authors: Irmak Emrah
Published: March 2021

Due to the highly infectious nature of the novel coronavirus (COVID‐19) disease, excessive number of patients waits in the line for chest X‐ray examination, which overloads the clinicians and radiologists and negatively affects the patient's treatment, prognosis and control of the pandemic. Now that the clinical facilities such as the intensive care units and the mechanical ventilators are very limited in the face of this highly contagious disease, it becomes quite important to classify the patients according to their severity levels. This paper presents a novel implementation of convolutional neural network (CNN) approach for COVID‐19 disease severity classification (assessment). An automated CNN model is designed and proposed to divide COVID‐19 patients into four severity classes as mild, moderate, severe, and critical with an average accuracy of 95.52% using chest X‐ray images as input. Experimental results on a sufficiently large number of chest X‐ray images demonstrate the effectiveness of CNN model produced with the proposed framework. To the best of the author's knowledge, this is the first COVID‐19 disease severity assessment study with four stages (mild vs. moderate vs. severe vs. critical) using a sufficiently large number of X‐ray images dataset and CNN whose almost all hyper‐parameters are automatically tuned by the grid search optimiser.
Lemon‐YOLO: An efficient object detection method for lemons in the natural environment
Authors: Li Guojin , Huang Xiaojie , Ai Jiaoyan , Yi Zeren , Xie Wei
Published: March 2021

Efficient Intelligent detection is a key technology in automatic harvesting robots. However, citrus detection is still a challenging task because of varying illumination, random occlusion and colour similarity between fruits and leaves in natural conditions. In this paper, a detection method called Lemon‐YOLO (L‐YOLO) is proposed to improve the accuracy and real‐time performance of lemon detection in the natural environment. The SE_ResGNet34 network is designed to replace DarkNet53 network in YOLOv3 algorithm as a new backbone of feature extraction. It can enhance the propagation of features, and needs less parameter, which helps to achieve higher accuracy and speed. Moreover, the SE_ResNet module is added to the detection block, to improve the quality of representations produced from the network by strengthening the convolutional features of channels. The experimental results show that the proposed L‐YOLO has an average accuracy(AP) of 96.28% and a detection speed of 106 frames per second (FPS) on the lemon test set, which is 5.68% and 28 FPS higher than the YOLOv3, respectively. The results indicate that the L‐YOLO method has superior detection performance. It can recognize and locate lemons in the natural environment more efficiently, providing technical support for the machine's picking lemon and other fruits.
Physically-based modelling for sheet metal cone parts forming under blast loading
Authors: Alipour Roozbeh
Published: March 2021

Forming sheet metals under blast loading or the explosive forming technique has many advantages for productions, but it is restricted due to its accuracy. This paper introduces a novel theoretical-empirical study for explosive sheet metal forming based on the simple plasticity principles. It provides a method of producing the sheet metal cone parts forming under blast loading, including an analytical model and experimental validation. Firstly, a theoretical-empirical model for cone forming based on underwater explosion employing the impulse method is developed. The model on the whole revealed the relationships among the geometrical parameters of forming a process that is very useful to predict the certain explosive mass for complete forming a cone part. Afterward, a series of experiments are conducted to validate the developed model and also for the required modification in the solution. Comparing the theoretical-empirical solution and experimental results, the ability of the presented model for estimation of the explosive mass is demonstrated. Experimental results show that the theoretical model matched the experiments well.
Comparison of six gas turbine power cycle, a key to improve power plants
Authors: Golneshan Ali Akbar , Nemati Hossain
Published: March 2021

It is required to sake methods to improve the power plant performance. Most of the proposed methods can be commenced only in the design stapes. However, the main question of this study is “What can we do to improve the performance of a running power plant?” The first answer to this question is that monitoring the site and periodic overhaul can keep a power plant in its acceptable condition. However, this answer is very qualitatively and needs more precise information like which parameters shall be monitored or which equipment needs more care in the overhaul. In this study, important parameters and the method of their calculations are introduced that must be monitored and compared. Six similar gas turbine power cycles were selected to be compared deeply during a day in this study. In this way, many data were collected every five minutes. Unlike most of the previous studies, this one concerns with maintenance policy and repair strategy. Results of this comparison lead to answer to these questions that which equipment needs special care? Finally, it was shown that in each unit, which equipment needs more attention and which one can be considered as a standard for the others.
Effect of ambient temperature on the formation mechanism of PTFE liner transfer film of spherical plain bearings
Authors: Qiu Ming , Tian Kai-Wen , Zhang Ya-Tao
Published: March 2021

The relationship between the formation of the transfer film and the tribological properties of the self-lubricating spherical plain bearing was studied at the ambient temperature of 25–145 °C. The results show that the wear, friction coefficient and friction temperature increase of the spherical plain bearings all decreased first and then increased with the increase of the ambient temperature. The general trend is that the bearing has the most excellent anti-friction and wear resistance at 55–85 °C. An increase in ambient temperature will accelerate the formation speed of PTFE transfer film and shorten the running-in period of the bearing, but the ambient temperature above 85 °C will shorten the duration of the PTFE transfer film, thus accelerating the bearing into the degradation period. The transfer film coverage of the liner after wear was characterized, and it was found that the transfer film coverage was the largest when the ambient temperature was 85 °C. The wear form of the bearing is mainly abrasive wear and adhesive wear, and the aramid fiber is more prone to adhesive wear. The anti-friction effect of the bearing is determined by the PTFE transfer film. Elevated ambient temperature can promote the formation of PTFE transfer film and enhance the antifriction effect, but if the ambient temperature is too high, the wear resistance of the PTFE transfer film will be reduced, thus reducing the friction reduction effect.
Design and error compensation of active mechanically automated guided vehicle
Authors: Yan Jianqiang , Li Mi , Chen Zhongxiang , Li Yihang
Published: March 2021

To reduce the navigation control cost, this paper proposes a mechanical guidance control scheme that uses a cam-link mechanism as a steering control mechanism for an automated guided vehicle with a fixed driving path. According to the steering principle, a mathematical model of the steering system and the driving trajectory are established. By setting the boundary conditions, the vehicle trajectory is modeled using a quintic polynomial. The contour of the directional control cam is obtained based on the equation of the vehicle trajectory. Because errors occur in actual machining and assembly processes, errors will be classified based on their impact on the trajectory. The effects of various errors on the trajectory are quantitatively determined by using simulation methods with different parameters. Furthermore, an error compensation approach is designed to reduce the influence of the error on the trajectory directly or indirectly. Finally, experiment results illustrate that the adjustment accuracy of the proposed automated guided vehicle trajectory is 2 mm.
A Case Study of Adopting European Experience of Office Hours to Improve Off-class Instructor-student Interaction in Private Universities in China
Authors: Wu Shaoying
Published: March 2021

To integrate with international standards, the University of Sanya explores European experiences in teaching and management. In 2016, the university promoted a campus-wide office-hour policy to improve student-teacher communication after class. However, after four years of implementation, most teachers believe such a policy failed to achieve the goal. Therefore, the author delivers questionnaires and interviews to students and teachers from selected business majors. This paper finds that office hour was an inferior way to communicate as in China students are allowed to have teachers' personal contact information. And students learning behavior is key to off-class communication. Moreover, the working environment affects teachers attitudes towards office hour. Office hour is a small case but can be inspiring to the future adoption of foreign experience in education as pre-investigation and localization do matter.
Clearing the Final Hurdle: Getting Students to Engage with Feedback in Higher Education
Authors: Wolstencroft Peter , de Main Lean
Published: March 2021

Higher Education within the UK over the last fifty years has increasingly been defined by the end product and this means that both students and lecturers tend to focus on the outcome rather than the process. For many students this means that assessments are seen as barriers to their final grade, rather than as a support to help them reflect on their performance. The purpose of this paper is to explore how students can become more engaged with the comments made on assessments. It concludes by suggesting that whilst audio feedback has proved to be successful in this respect, video feedback might well be an even better way of encouraging students to listen to what they are being told and then improve subsequent work.
Contributing factors of classroom teaching quality and improving strategies in Chinese universities: From Students’ Perspective
Authors: Yuan Qin , Chen Bei , Pengsheng Wen
Published: March 2021

The teaching quality of universities directly affects the quality of national talent training. The Academic Affairs Office of Chinese universities, through the establishment of the relevant classroom teaching evaluation index system, plays a supervisory role on the classroom teaching quality. Based on the index system, students evaluate classroom teaching quality before selecting a course online at the end of each semester. The paper reports the findings of a small-scale survey carried out in the X University of China within the framework of the ERASMUS+ENTEP project. Through the questionnaires and interviews given to the students of X University, the objective of the study was to identify the index that teachers need to strengthen and then try to put forward some improvement strategies. The results from the survey highlight the factors that contribute to the high quality of undergraduate classroom teaching from students’ perspective, including the unvalued personal moral cultivation of teachers, more attention to the indoctrination of knowledge and ignore the inspiration of mind and the effective interaction between teachers and students. The evidence from this survey suggests that in order to improve the undergraduate classroom teaching quality, teachers should shift the concept of teaching and learning, from the indoctrination of knowledge to the mobilization of students’ enthusiasm, inspire them to think, associate and innovate, and guide the individual student to become an integrated well-developed person.
Educational ecosystem development based on quality management standards
Authors: Levina Elena , Prokofieva Elena
Published: March 2021

The educational system is sensitive to all changes in the world space. The transition to a digital society is determined by significant changes in the philosophical foundations of human activity and creating products, especially intellectual ones. The information and digital revolutions have significantly changed the spheres of cognition, perception and human activity, putting them on the rails of continuous education in an actively developing dynamic world. In order to evolve, it is necessary to transfer the existing system of knowledge and sciences to the new, digital generation of people, to form mechanisms of continuous learning, to generate innovations - the solution to this problem lies with the education system, referring to all its levels. The change in the education model is not only about the digitalization of educational processes. The “human-centered” approach is global. The authors consider the methodology for the development of educational ecosystems as a new norm of educational activity, revealing the concepts of educational ecology and analyzing the principles of implementing the ecosystem approach from the standpoint of achieving the quality of education.
Enhancing teaching practices at Penza State University
Authors: Vasin Sergei , Razuvaeva Tatiana , Korolev Konstantin
Published: March 2021

The article examines the major challenges that Russian higher education institutions face while introducing the principles of the Bologna Process into current teaching practice. Their participation in the international projects together with European HEIs is seen as one of the possible ways to overcome the encountered difficulties. The role of the Capacity Building projects under the Erasmus+ Programme is illustrated by an example of Penza State University and its involvement in the ENTEP project (Enhancing Teaching Practice in Higher Education in RUSSIA and CHINA). The main stages of implementing the project at PSU are revealed, the project outputs and outcomes are described, as well as the perspectives for further adaptation of the project results are outlined. The article describes the professional development course “Enhancing teaching practices at PSU”, which was developed within the ENTEP project and offered for teaching and administrative staff of the university. The project contribution at the university is assessed in terms of adopting the best teaching practices in the context of the Bologna Process and European Higher Education Area.
Interdisciplinary integration as a basis for forming an environment-oriented component of competencies
Authors: Vasina Olga , Ponomariova Olga , Kotelnikova Tatiana
Published: March 2021

Most disciplines of the compulsory part of the curriculum and its part defined by education stakeholders in line with the corresponding study field have a significant resource for forming an environment-oriented component of competencies in students. The authors aim at identifying and showing the possibilities of interdisciplinary integration in the formation of the environment-oriented component of universal and professional competencies in the process of fulfilling the requirements of the Federal State Educational Standards. The article illustrates the practice of implementing interdisciplinary integration in higher education when forming the environment-oriented component of competencies by means of experimental work within the educational process at Penza State University and A.V. Khrulev Penza Branch of the Military Academy of Logistics. It is shown that the interdisciplinary integration implies not complementing the disciplines with additional ecological content, but creating a new system with emergent properties that are of interest of both environmental and field-specific education.
Multiple-choice questions and essays in assessing economics
Authors: Vlazneva Svetlana , Androsova Olga
Published: March 2021

The article is devoted to assessment tools in teaching economics. The authors distinguish and define four levels of understanding economics: elementary, intermediate, systemic and creative. They describe multiple choice questions and essay questions as two possible assessment tools in teaching economics. Multiple-choice questions are represented as the most popular testing format. The advantages of multiple-choice questions include low grading costs, perceived objectivity and availability of comparative analysis. The authors have developed multiple-choice tests, which measure students’ knowledge at three first levels of understanding economics. They enable instructors to see where exactly the students’ understanding has stopped and provide guidance. The authors conclude that multiple-choice questions can be used to measure the basic levels of students’ understanding economics. In measuring higher levels the essay as an assessment tool has a great potential. The authors highlight the advantages and pitfalls of essay testing in economics.
Professional Training Scheme in USUE: COVID-19 Pandemic Impact
Authors: Vidrevich Marina , Pervukhina Irina
Published: March 2021

Over the past decades, the Russian tertiary sector has undergone profound changes caused by economic and social factors. The paper focuses on the challenges that modern universities are facing nowadays. One of the challenges is pedagogical and methodological professional development of academic staff, which has been affected by the COVID-19 crisis. However, a rapid shift to online teaching and learning has offered new opportunities to capacity building of staff and faculty who have learned and tested new tools and systems to enable distance teaching and learning. USUE case is considered.
The impact of digital technology on the quality of higher education
Authors: Zaborova Elena
Published: March 2021

COVID-19 pandemic intensified the transition to online learning practices. The article aims to analyse how students perceive distance education quality compared to face-to-face education mode. The author argues that the groups of social actors, interested in the promotion of distance education in higher schools, include: university leadership, geographically and physically disadvantaged students. In the period 2015-2020 the group of USUE researchers conducted a series of students’ surveys. Analysing the survey findings, the author states that despite the benefits of distance education, students consider that the quality of distance learning is inferior to the traditional face-to-face education mode. Among the problems faced by students in distance learning, is their inability to select information, assess its reliability, and differentiate significant information from insignificant. It is concluded that it is of great importance to continue research into the impacts of digitalization on the quality of higher education.
Rauchverhalten von Krebspatienten nach Kehlkopfteilresektion: Welche Bedeutung hat die Kausalattribution?
Authors: Münnemann Anika , Meyer Alexandra , Engelmann Dorit , Boehm Andreas , Breitenstein Kerstin , Ulrich Angela , Guntinas-Lichius Orlando , Schock Elke-Juliane , Keszte Judith , Ernst Jochen
Published: March 2021

Ziel der Studie Etwa 4000 Personen erkranken in Deutschland jährlich an Kehlkopfkrebs. Als einer der wichtigsten Risikofaktoren gilt das Rauchen. Die Studie untersucht den Zusammenhang von Kausalattribution und Rauchverhalten bei Patienten mit Kehlkopfkrebs nach Kehlkopfteilresektion (KTR) und den Einfluss der Kausalattribution auf das Rauchverhalten nach KTR.

Methodik In einer multizentrischen prospektiven Kohortenstudie zwischen 2007 und 2013 wurden Patienten mit Kehlkopfkrebs zu 4 Befragungszeitpunkten mit Fragebogen befragt: t1 (zwischen Diagnosestellung und KTR), eine Woche (t2), 3 Monate (t3) und 12 Monate (t4) nach KTR. Nachfolgend werden Daten der Messzeitpunkte t1 und t4 präsentiert. Wesentlicher Gegenstand der deskriptiven Auswertung waren die Kausalattribution (offene Antwort mit anschließender Kodierung entsprechend der wichtigsten Ursachenzuschreibungen sowie früheres und aktuelles Rauchverhalten anhand des DIA-X-Interviewsystems). Die Patienten wurden entsprechend ihrer Kausalattributionen gruppiert und hinsichtlich des Rauchverhaltens verglichen.

Ergebnisse Zu den Zeitpunkten t1 und t4 wurden 134 Patienten (Durchschnittsalter 62 Jahre, 93% männlich) interviewt. Ein Viertel der Befragten (25,4%) benennt keine Ursache für die Erkrankung. Wird eine Kausalattribution genannt, ist das Rauchen die am häufigsten beschriebene Ursache (43,3%). Bei aktiven Rauchern dieser Gruppe sinkt die Anzahl der täglich gerauchten Zigaretten nach KTR signifikant um 6 Zigaretten (p=0,001) auf durchschnittlich 11 Zigaretten pro Tag. In keiner Gruppe sinkt der Anteil der Rauchenden signifikant.

Schlussfolgerung Die Kausalattribution hat keinen signifikanten Einfluss auf die Rauchentwöhnungsrate. Aktive Raucher reduzieren nach KTR die Menge der Zigaretten signifikant. Dieser Effekt ist noch deutlicher, wenn eine Kausalattribution vorliegt. Indem psychoonkologische Betreuungsangebote, Beratungsgespräche und Rauchentwöhnungsprogramme die Kausalattribution unter Einbezug der Fallspezifik thematisieren, kann dies zu einem prognostisch günstigeren Rauchverhalten nach KTR beitragen.
Signal-To-Noise Ratio Calculations to Validate Sensor Positioning for Facial Muscle Assessment Using Noninvasive Facial Electromyography
Authors: Frank Konstantin , Moellhoff Nicholas , Kaiser Antonia , Alfertshofer Michael , Gotkin Robert H. , Patel Ashit , Smith Michael P. , Mardini Samir , Gavril Diana , Cotofana Sebastian
Published: March 2021

The evaluation of neuromodulator treatment outcomes can be performed by noninvasive surface-derived facial electromyography (fEMG) which can detect cumulative muscle fiber activity deep to the skin. The objective of the present study is to identify the most reliable facial locations where the motor unit action potentials (MUAPs) of various facial muscles can be quantified during fEMG measurements. The study population consisted of five males and seven females (31.0 [12.9] years, body mass index of 22.15 [1.6] kg/m2). Facial muscle activity was assessed in several facial regions in each patient for their respective muscle activity utilizing noninvasive surface-derived fEMG. Variables of interest were the average root mean square of three performed muscle contractions (= signal) (µV), mean root mean square between those contraction with the face in a relaxed facial expression (= baseline noise) (µV), and the signal to noise ratio (SNR). A total of 1,709 processed fEMG signals revealed one specific reliable location in each investigated region based on each muscle's anatomy, on the highest value of the SNR, on the lowest value for the baseline noise, and on the practicability to position the sensor while performing a facial expression. The results of this exploratory study may help guiding future researchers and practitioners in designing study protocols and measuring individual facial MUAP when utilizing fEMG. The locations presented herein were selected based on the measured parameters (SNR, signal, baseline noise) and on the practicability and reproducibility of sensor placement.
Molecular dynamics simulation on the splitting of shear flow in nanochannels
Authors: Yu Hang , Tian Zhengyu , Yang Fan , Li Hua
Published: March 2021

With the vigorous development of micro-/nanoscience and micro-/nanotechnology, fluid flows at the micro-/nanoscale have become an important research field. The molecular dynamics simulations of Couette flow in a nanochannel are carried out in this paper. In order to evaluate the non-equilibrium effect of the rarefied flow field, a “sampling-classification” method is proposed. Through this newly developed method, we found that the rarefied gas flow in nanochannels can be regarded as the superposition of two independent shear flows with the same shear rate. A nondimensional quantity “vd” is proposed to quantificationally evaluate the degree of splitting, or more specifically, the non-equilibrium state, of the flow field. Further study shows that the growth in roughness will aggravate this rarefied non-equilibrium effect, while the increase in system temperature leads to an opposite result. The “sampling-classification” method developed in this article can provide a new analytical idea for subsequent rarefied flow researchers, and the splittable phenomenon of shear flow discovered can also be regarded as an important property of rarefied flows that is worthy of further study.
Bots are less central than verified accounts during contentious political events
Authors: González-Bailón Sandra , De Domenico Manlio
Published: March 2021

Significance

Online networks carry benefits and risks with high-stakes consequences during contentious political events: They can be tools for organization and awareness, or tools for disinformation and conflict. We combine social media and web-tracking data to measure differences on the visibility of news sources during two events that involved massive political mobilizations in two different countries and time periods. We contextualize the role of social media as an entry point to news, and we cast doubts on the impact that bot activity had on the coverage of those mobilizations. We show that verified, blue-badge accounts were significantly more visible and central. Our findings provide evidence to evaluate the role of social media in facilitating information campaigns and eroding traditional gatekeeping roles.
Global hydroclimatic response to tropical volcanic eruptions over the last millennium
Authors: Tejedor Ernesto , Steiger Nathan J. , Smerdon Jason E. , Serrano-Notivoli Roberto , Vuille Mathias
Published: March 2021

Significance

Future large tropical volcanic eruptions will induce global hydroclimatic changes, superimposed on anthropogenic climate change. Understanding how volcanic eruptions affect global hydroclimate is therefore critically important. Tejedor et al. use a new paleoclimatic product, which combines information from high-resolution proxies and climate models, to estimate volcanic impacts on hydroclimate over the last millennium. They find that past eruptions caused severe drying in tropical Africa and across Central Asia and the Middle East and significantly wetter conditions over Oceania and the South American monsoon region, some of which persisted for a decade or longer. These proxy-based findings suggest that, relative to estimates from a state-of-the-art climate model, much larger and persistent hydroclimatic changes are possible across regions of important socioeconomic activity.
A synthetic 5,3-cross-link in the cell wall of rod-shaped Gram-positive bacteria
Authors: Dik David A. , Zhang Nan , Sturgell Emily J. , Sanchez Brittany B. , Chen Jason S. , Webb Bill , Vanderpool Kimberly G. , Schultz Peter G.
Published: March 2021

Significance

The cell wall of bacteria is a biopolymer formed of glycan chains cross-linked by interconnecting peptide stems. Elucidating the structure, biosynthesis, and recycling mechanisms of the cell wall is important to understanding the mechanism of action of β-lactam antibiotics and the development of new antibiotics. Here we use a synthetic biology approach to probe the structural and biosynthetic constraints of cell-wall architecture by introducing noncanonical building blocks into the cell walls of living bacteria. We show that a Gram-positive bacterium remains viable under circumstances where approximately 20% of the cell wall is interconnected by synthetic 5,3-cross-links, a cross-linking arrangement absent in Nature. Characterization of these synthetic cell-wall cross-links highlights key differences in cell-wall recycling between Gram-negative and -positive bacteria.
Resin-acid derivatives bind to multiple sites on the voltage-sensor domain of the Shaker potassium channel
Authors: Silverå Ejneby Malin , Gromova Arina , Ottosson Nina E. , Borg Stina , Estrada-Mondragón Argel , Yazdi Samira , Apostolakis Panagiotis , Elinder Fredrik , Delemotte Lucie
Published: March 2021

Voltage-gated potassium (KV) channels can be opened by negatively charged resin acids and their derivatives. These resin acids have been proposed to attract the positively charged voltage-sensor helix (S4) toward the extracellular side of the membrane by binding to a pocket located between the lipid-facing extracellular ends of the transmembrane segments S3 and S4. By contrast to this proposed mechanism, neutralization of the top gating charge of the Shaker KV channel increased resin-acid–induced opening, suggesting other mechanisms and sites of action. Here, we explore the binding of two resin-acid derivatives, Wu50 and Wu161, to the activated/open state of the Shaker KV channel by a combination of in silico docking, molecular dynamics simulations, and electrophysiology of mutated channels. We identified three potential resin-acid–binding sites around S4: (1) the S3/S4 site previously suggested, in which positively charged residues introduced at the top of S4 are critical to keep the compound bound, (2) a site in the cleft between S4 and the pore domain (S4/pore site), in which a tryptophan at the top of S6 and the top gating charge of S4 keeps the compound bound, and (3) a site located on the extracellular side of the voltage-sensor domain, in a cleft formed by S1–S4 (the top-VSD site). The multiple binding sites around S4 and the anticipated helical-screw motion of the helix during activation make the effect of resin-acid derivatives on channel function intricate. The propensity of a specific resin acid to activate and open a voltage-gated channel likely depends on its exact binding dynamics and the types of interactions it can form with the protein in a state-specific manner.
Degradation of methylene blue in liquid using high-voltage pulsed discharge plasma synergizing iron-based catalyst-activated persulfate
Authors: Yang De-Zheng , Zhou Xiong-Feng , Liang Jian-Ping , Xu Qing-Nan , Wang Hong-Li , Yang Kun , Wang Bo , Wang Wen-Chun
Published: March 2021

In this work, high-voltage pulsed Ar gas–liquid discharge synergizing iron-based catalyst-activated persulfate (PS) was employed to degrade methylene blue (MB) in water. The catalytic performances of two types of iron-based catalysts, namely the homogeneous catalyst Fe2+ and the heterogeneous catalyst nano-Fe3O4, were compared. Correspondingly, the plasma gas temperature and excited species were calculated and diagnosed using optical emission spectra. It was found that the introduced plasma process significantly enhanced the degradation efficiency of MB by the PS/Fe2+ and the PS/Fe3O4 systems. After 20 min of treatment, the MB degradation efficiency reaches 97.5% and 83.1% in the hybrid plasma/PS/Fe2+ and plasma/PS/Fe3O4 systems, respectively, which is 37.9% and 35.6% higher than that in the PS/Fe2+ and PS/Fe3O4 systems. The synergistic mechanism and key reactive species responsible for MB degradation in hybrid plasma/PS/Fe2+ and plasma/PS/Fe3O4 were explored using the addition of radical scavengers and control experiments under various conditions. The homogeneous catalyst Fe2+ exhibits better activation performance in PS and plasma than that of the heterogeneous catalyst nano-Fe3O4.
Variational quantum compiling with double Q-learning
Authors: He Zhimin , Li Lvzhou , Zheng Shenggen , Li Yongyao , Situ Haozhen
Published: March 2021

Quantum compiling aims to construct a quantum circuitVby quantum gates drawn from a native gate alphabet, which is functionally equivalent to the target unitaryU. It is a crucial stage for the running of quantum algorithms on noisy intermediate-scale quantum (NISQ) devices. However, the space for structure exploration of quantum circuit is enormous, resulting in the requirement of human expertise, hundreds of experimentations or modifications from existing quantum circuits. In this paper, we propose a variational quantum compiling (VQC) algorithm based on reinforcement learning, in order to automatically design the structure of quantum circuit for VQC with no human intervention. An agent is trained to sequentially select quantum gates from the native gate alphabet and the qubits they act on by doubleQ-learning withϵ-greedy exploration strategy and experience replay. At first, the agent randomly explores a number of quantum circuits with different structures, and then iteratively discovers structures with higher performance on the learning task. Simulation results show that the proposed method can make exact compilations with less quantum gates compared to previous VQC algorithms. It can reduce the errors of quantum algorithms due to decoherence process and gate noise in NISQ devices, and enable quantum algorithms especially for complex algorithms to be executed within coherence time.
A novel multi-banding application of magnetic field to convective transport system filled with porous medium and hybrid nanofluid
Authors: Manna Nirmal K , Mondal Milan K , Biswas Nirmalendu
Published: March 2021

To enhance the controllability of transport phenomena where magnetic fields are coupled with other multiphysics, a concept of multi-banding distribution of the magnetic field is presented in this work. For this study, a typical differentially heated convective system (of square shape) is considered with porous media saturated Cu–Al2O3/water hybrid nanofluid. The isothermal heating and cooling applied on the sidewalls of the system induce a buoyant flow, which is resisted by porous media and is dampened intermittently by the banded form of application of magnetic fields. The multi-banding distribution of magnetic fields is illustrated using four-band, two-band, and one-band configurations (all having the same effective length of the magnetic field). The results are generated by an in-house code adopting the finite volume method and the Brinkman-Forchheimer-Darcy model. For a set of selective parameters of the Hartmann number, Darcy number, hybrid nanofluid concentration, and Darcy-Rayleigh number, the study reveals that the multi-banding of the magnetic field through different numbers of bands has significant effects on transport phenomena and heat transfer. Heat transfer with the two-banded magnetic field is found more. Overall, the multi-banding technique is energy efficient compared to the whole domain magnetic field. This technique could be a prospective tool to control convective transports effectively and could open an area of potential researches in the area of multi-physical applications.
Single phase based study of Ag-Cu/EO Williamson hybrid nanofluid flow over a stretching surface with shape factor
Authors: Jamshed Wasim , Devi Suriya Uma , Nisar Kottakkaran Sooppy
Published: March 2021

Hybrid nanofluids is the suspension of two different types of nanoparticles in the base fluid. This enhances the heat transfer capabilities of the ordinary fluids and prove to better heat exponent as compare to the nanofluids. In this research, we investigate the nanofluid for its flow and heat transport features by subjecting it to a slippery surface. The fluid motion disturbance is achieved by with the utilization of non-linear, uniform horizontal porous stretching of the surface with in a Darcy type porous media. The effect of nanoparticle shapes, porous medium, variable thermal conductivity and thermal radiation are also included in this analysis. A numerical method, Keller box is used to find the self-similar solution of equations. Two different types of nanoparticles, Copper(Cu) and Silver(Ag) with non-Newtonian Engine Oil (EO) based fluid have been taken into consideration for our analysis. The valuable finding of this study is that the comparative heat transfer rate of Williamson hybrid nanofluids (Ag − Cu/EO) gradually more increases as compared to conventional nanofluids (Cu − EO). Moreover, Lamina-shaped particles result in the most significant temperature in the boundary layer, while the lowest temperature is observed in spherical-shaped nanoparticles. Finally entropy of the system exaggerates with the incorporation of nanoparticle percentage by volume, thermal radiation, variable thermal conductivity and Williamson variable.
Method validation for pesticide multiresidue analysis of pyrethroid on green beans of arabica gayo coffee using gas chromatography-electron capture detector (GC-ECD)
Authors: Yusuf M , Idroes R , Saiful  , Lelifajri  , Bakri T K , Satria M , Nufus H , Yuswandi I , Helwani Z , Muslem  , Marlina
Published: March 2021

The method validation for the pesticide multi-residue analysis of pyrethroid on green beans of Gayo Arabica coffee using the Gas Chromatography-Electron Capture Detector (GC-ECD) method was carried out. Coffee samples were taken at three locations in Bener Meriah Regency, namely Bandar, Permata, and Wih Pesam. The pyrethroid residues measured were cypermethrin, deltamethrin, and permethrin. The coffee samples were extracted by QuEChERS using a solvent of 1% acetic acid in acetonitrile. The validation parameters tested included selectivity, linearity, Limit of Detection (LoD), Limit of Quantification (LoQ), precision, and accuracy. The results showed that this method was selective, with only three pyrethroid peaks detected. The method was linear in the concentration ranges of 0.01-0.30 μg/mL, with the correlation coefficient of ≥0.99 for all samples. The sensitivity was excellent with LoD and LoQ of 0.0151-0.0420 μg/mL and 0.0504-0.1400 μg/mL. The accuracy and precision were very well with %recovery and % RSD of 83.85-105.19 and 1.5-8.3 for cypermethrin, 75.17-89.34, and 2.0-11.7 deltamethrin, and 83.16-109.43 and 3.1-3.6 for permethrin, respectively. The method application showed that no pyrethroid residues were found in all coffee samples. The result was confirmed by the obtained % recovery in ranges of 90-109 % for all samples.
Characterisation and cytotoxicity assay of curcumin nanostructured lipid carrier on HeLa cells
Authors: Rabima  , Oktamauri A
Published: March 2021

Low bioavailability is major problem in the use of curcumin. Nanostructured Lipid Carrier (NLC) is an interesting generation of lipid-based nanoparticles, because of its ability to increase the bioavailability of drugs. The objectives of this study were to make a formulation of curcumin in NLC (CRM-NLC) preparations, to determine its characteristic and to examine the cytotoxic effects of CRM-NLC on HeLa cells in vitro. CRM-NLC was made by the method of evaporation and diffusion of solvents in aqueous systems then followed by ultrasonication. Its particle size, polydispersity index, zeta potential were determined by using Particle Size Analyzer. The structure and morphology were observed by using Transmission Electron Microscopy then its cytotoxic activity toward HeLa cells was examined by using the MTT method then Half Maximal Inhibition Concentration (IC50) was determined. CRM-NLC produced in this study had an average particle size of 17.4 nm, a polydispersity index of 0.574, the zeta potential of -63.43 mV, with structure and the morphology of CRM-NLC was round and smooth surface. CRM-NLC IC50 value obtained in this study was 8,872 μg / mL. This study has succeeded in making CRM-NLC preparation with good characteristics and improving curcumin activity on HeLa cells.
Co-integration analysis between rice production and exchange reserves with rice consumption in Indonesia
Authors: Mustafa  , Aprilia A P , Fauzi T
Published: March 2021

Rice production is increasing every year but Indonesia still to import rice which is directly related to the use of foreign exchange reserves. Volume of rice import is caused by the small amount of rice production. If the volume of rice import is only a small amount means the amount of rice production is large. Large volume of imports will may have impact on foreign exchange reserves and constraints the ability to import raw materials and capital goods needed for development. The purpose of this study is to determine the co- integration between foreign exchange reserves and rice imports in Indonesia. The method used in this study is the Error Correction Model (ECM) analysis. The results of the study showed that there was co-integration of rice production and rice import while there was no co-integration of foreign exchange reserves and rice import that is the variables did not have a long-term relationship.
Preliminary Study on the Basic Characteristics of Isopropyl Esters Used As Insulating Liquid
Authors: Rajab A , Ramadhani J , Kurniawan R , Qibran K , Latief M , Hamid MI
Published: March 2021

The paper presents the basic properties evaluation of isopropyl esters for an insulating liquid in oil-filled transformer. Two kinds of isopropyl esters, namely, isopropyl palmitate and isopropyl stearate, were synthesized from isopropyl alcohol and palmitate and stearate acids. The resulted isopropyl esters were then evaluated for their basic properties such as breakdown voltage, viscosity, density, acidity, and water-based on the ASTM D 6871 standard specification. The investigation results show that the viscosity and the Density of both isopropyl esters meet the standard’s values well. The breakdown voltage of isopropyl stearate is higher than the standard specification, whereas that of isopropyl palmitate is less than the standard value. The water content of both liquids is still much higher than the value specified by the standard.
Cleaner production analysis at hospital wastewater treatment plant
Authors: Amala K , Budhi S , Kusnoputranto H
Published: March 2021

The construction of WWTP (Wastewater Treatment Process) hospital should prioritize the environmental aspect and apply the principle of sustainable development so that the environmental impact can be minimized and optimize its management. The wastewater management strategy used in Hospital X uses an end of pipe strategy that focuses only on sewage treatment and disposal, so as not to completely solve existing environmental problems. Cleaner production analysis is applied to improve wastewater management and WWTP performance thus improving WWTP’s operational cost-efficiency. The implementation of cleaner production can be one of the alternatives to reduce management costs through the identification of opportunities also inefficiencies found in WWTP management in hospitals. The analysis was carried out using descriptive analysis through the depiction of the water balance in WWTP treatment, the analysis then continued using fishbone diagrams to see the efficiency opportunities that can be applied. The results showed wastewater produced from the hospital met the standard requirements of wastewater quality so that it can be reused as one of the raw water sources for the hospital’s operational activities.
The effect of chopping raw material on composting result with the biopore infiltration hole method
Authors: Ruslinda Y , Aziz R , Sari N , Arum L S
Published: March 2021

This research aims to analyze the effect of chopping raw material on compost quality and quantity that was made with the biopore infiltration hole method. The composting was done in duplo on the backyard with clay soil type, and the water infiltration rate was 0.3 cm/hour. The holes were made with 10 cm of diameter, 100 cm of depth, and the distance between holes were 50 cm. There were four composition variations on this research i.e 50% yard waste and 50% food waste with and without chopping, 70% food waste and 30% yard waste with and without chopping. The chopping was using an organic waste chopping machine so that the waste size became 0.3-1.5 cm, while the size waste without chopping was ≥ 3 cm. The compost analysis was done toward maturity, compost quality (physical elements and macro elements), and compost quantity. The composting process took 65-80 days to get riped. The best variation was chosen by the scoring method. The result showed that compost with 50% yard waste and 50% food waste was the best variation because the compost quality has met the standard for physical elements and macro elements, it produced more compost quantity. The chopping process could speed up the composting time until 15 days.
The Sublethal Effects of Tannery Wastewater Exposure on Oxygen Consumption Levels and Operculum Movement of Indonesia Mahseer Fish
Authors: Ihsan T , Edwin T , Zupit J R , Ananda S F , Nofrita
Published: March 2021

This study aimed to analyze the effect of tannery wastewater exposure of Padang Panjang, Indonesia, on the level of oxygen consumption (OC) and the operculum movement of the Mahseer fish (Tor tambra CV). Mahseer is an endemic fish in the BatangAnai River in West Sumatra Province. The study is started by determining the acute toxicity value of LC50-96h using a static method within 96 hours of observation. Based on the results of the Probit Method, the LC50-96h amount of mahseer was 15.41%. Furthermore, variations in the wastewater concentration were 0%, 10%, 20%, and 30% of the LC50-96h value. Observations were carried out for 30 days in triplicate. Based on OC value, the concentration of 10%, 20% and 30% has decreased by 0.13 mg O2/g.hours; 0.18 mg O2/g.hours, and 0.27 mg O2/g.hours consecutively otherwise in control, treatment increased by 0.05 mg O2/g. While the operculum movement, the concentration of 10%, 20%, and 30% have increased by 90 times/minute, 108 times/minute, and 116 times/minute, respectively. In control, treatment has risen by 44 times/minute. OC’s correlation value and mahseer’s operculum movement ranged from 0.94 to 0.97, which means the correlation was reliable. The significance value obtained p <0.05, which means that there were significant differences in OC values and movements of the mahseer’s operculum.