bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical modeling of wind turbine with vertical axis using turbulence model k − ω in ANSYS FLUENT
Authors: Hamdamov Muzaffar , Bozorov Bobir , Mamataliyeva Hulkaroy , Ergashov Dilshod
Published: August 2023

The paper considers a variant of the problem of modeling the flow around a developed wind turbine. Since the task is reduced to modeling a flat task, the 2D design mode was chosen. The k – ω turbulent model was used to model the vertical axis wind turbine. In the research process, experimental methods for measuring wind speed and torque, methods of mathematical modeling, and computational fluid dynamics were used. The object of research is a wind turbine designed to generate electricity from wind energy. The research aims to develop a wind turbine with a vertical axis and radial frames, equipped with flat blades and stoppers, operating at low wind speeds.

Research methods: in the research process, experimental methods for measuring wind speed and torque, methods of mathematical modeling, and computational hydrodynamics were used. A computational experiment HTBO with four sections based on the ANSYS environment was carried out. Scope of the results: the results will be used in designing and manufacturing wind turbines operating at low wind speeds. Ultimately, low-power wind turbines will be developed. Economic efficiency and significance of the work: the wind turbine being developed is made with available purchased materials and will have a short payback period. It is used for domestic and other purposes where access to electricity is limited.
Modeling determination of landslide pressure of Akhangaran reservoir ground masses
Authors: Khudaykulov S.I. , Kodirov D.T. , Sherbaev M.R. , Musurmonov M.A. , Abdivakhidov K.A.
Published: August 2023

Analyzing the landslide situation is one of the urgent scientific and practical problems in determining the conditions for carrying out construction works and protecting human life and economic sectors from danger. Landslides can cause economic damage, disable large structures and roads, destroy large areas of crops, and destroy villages and cities. In this study, for Akhangaran reservoir lands, techniques for assessing slope stability, ground mass stability during landslides, and landslide pressure were established for the scenario when soils exhibit both frictional and viscous qualities. These approaches took into consideration the internal factors impacting landslides. The obtained results are based on the development of activities that suppress the factors affecting the movement of landslides.
Reducing impact of embankment soils on shore support of bridge on the approaches to bridges
Authors: Mekhmonov Mashkhurbek , Uralov Akmal
Published: August 2023

The article defines the reduction of active ground pressure and amplitude-frequency characteristics by theoretical and practical studies on approaches to bridges by driving reinforced concrete piles into the embankment. Reinforced concrete piles were driven into the model of the roadbed, and vibrations were created using a vibrator mounted on piles. The frequency of these oscillations was 50 Hz, and the values of the oscillations were recorded at different points of the roadbed. Processing the obtained results made it possible to determine the distance between piles for different soils on the transition section reinforced with reinforced concrete piles. As a result, some of the vibrations in the roadbed are transmitted to the base using reinforced concrete piles. The amplitude-frequency characteristics (frequency response) of the vibrations of the embankment soils are decreasing.
System for determining state of continuous welded track
Authors: Khalfin Gali-Askar , Umarov Khasan , Purtseladze Irina , Yembergenov Murat
Published: August 2023

The article considers the main disadvantages of the existing method of examining the lashes of a jointless path, in which a pedestrian bypass of the sections of the canvas and their visual control is performed. A system for monitoring the temperature stresses of jointless rail lashes laid in the path is proposed, which allows monitoring the longitudinal displacement of the track throughout the entire life cycle: from the moment the rails are welded into long-length lashes, including their laying, and throughout further operation. The system makes it possible to monitor compliance with the optimal fixing temperature of rail lashes during their laying, welding and fixing, based on data obtained with the help of sensors, to determine the actual fixing temperature in the lashes of a jointless track; to control the optimal fixing temperature of rail lashes in areas of restoration of their integrity.
Numerical modeling of combined reinforcement concrete beam
Authors: Mavlonov Ravshanbek , Razzakov Sobirjon
Published: August 2023

Because polymer-composite reinforcements are a new material in construction, the possibilities of their use in load-bearing structures, including concrete beams, are somewhat limited by existing regulations. The research work implemented in this article is to study their strength and stiffness in cases where steel reinforcement is in the tensile zone and composite polymer reinforcement is in the compressive zone of concrete. Concrete beams with combined reinforcement are the object of the study, and the study of the stress-deformation state is its subject. The behavior of concrete beams with combined reinforcement under static load was studied. Considering the nonlinear properties of materials in the finite element method, their stress-strain states were investigated. A 3D beam model was created using the ANSYS Workbench 2022R1, and 3 series of samples were chosen and compared with hand calculations. The behavior of concrete beams with metal and composite reinforcement was carried out using numerical analysis. Also, the study’s results show that the role of the reinforcement installed in the compressive zone of the beam is better than the performance of the beam without the reinforcement installed in the compressive zone. Although the failure starts with the rebar in the tensile zone, the rebar installation in the compression zone shows an increase in the bearing capacity and stiffness of the beam.
Modeling development of optimal composition of non-autoclaved aerated concrete based on industrial waste
Authors: Shaumarov Said , Kandakhorov Sanjar , Babaev Askar , Kodirov Bakhodir
Published: August 2023

This article presents the modern state of energy-efficient residential building exterior wall constructions from aerated concrete, and the main properties of aerated concrete are analyzed. Properties of composite building materials, strength, and heat-technical properties depending on their structure are considered. Also, the analysis of existing problems in obtaining aerated concrete in the Republic of Uzbekistan is presented.

The results of research on the use of industrial waste in aerated concrete have shown that it is appropriate to continue research using physical-mechanical and chemical activation methods for the wide application of secondary filler activation, particularly in construction production.

The modern state of construction of external wall structures of energy-efficient residential buildings from aerated concrete is presented, in which the main properties of aerated concrete are analyzed. Properties of composite building materials, strength, and heat-technical properties depending on their structure are considered. Also, the analysis of existing problems in obtaining aerated concrete in the Republic of Uzbekistan is given.
Evaluation of the influence of the longitudinal slope of carriage roads on the tire life
Authors: Yusupov Umidbek , Mukhitdinov Akmal
Published: August 2023

This article presents an analysis of the results of an experiment conducted in the Muruntau quarry. All routes are divided into 5 groups depending on the average slope of the road. For the first group, routes with an average road slope from −1 to +1% were chosen; for the second group, with an average road slope from 1 to 3%; for the third, from 3 to 5%; for the fourth, from 5 to 7%; fifth more than 7%. The experiments were carried out on Komatsu HD785-7 dump trucks with a carrying capacity of 91 tons. According to the results of the experiment, it was found that the life of dump truck tires operated on routes with an average road slope of 6% is reduced by 2 times compared to tires operated on a horizontal road.
Retraction Note: Improving the bitumen properties with the introduction of energy-saving additives
Authors: Riskulov Alimjon , Ibodullaev Akhmadjon , Nurmetov Khurshidbek , Khojakhmedova Kholida
Published: August 2023

This paper has been formally retracted on ethical grounds because the article contains extensive and repeated instances of plagiarism. The authors are responsible for this mistake and apologise for it. Request approved by the proceedings Editor and the Publisher on August 2, 2023.
Full factorial experiment in research the parameters of a combined shaft of technological machines
Authors: Yunusov S. Z. , Kenjayev S. N. , Makhmudova Sh. A. , Islamova G. X.
Published: August 2023

This article provides the results of a full-factorial experiment for a combined shaft with an elastic support. The influence of the main parameters of the shaft on the bending vibrations of the shaft is considered, as the input parameters are the thickness and hardness of the elastic element, as well as the distance from the resultant force to the supports.
Statistical analysis and forecasting of cotton yield dynamics in Bukhara region
Authors: Vakhabov V. , Fayziev A. A.
Published: August 2023

Observations on some phenomena, the nature of which changes in time, are ordered sequences, which is called the time series. In the article, by the method of statistical analysis of time series, the statistical regularity of the series of dynamics of the average yield of cotton in the Bukhara region, the Republic of Uzbekistan (based on the materials of the CSO of the Republic of Uzbekistan for 2001-2019) was studied. Point and interval estimates for the average cotton yield were built with a 95% guarantee, explicit types of trends were determined, and yields in the region were predicted for subsequent years. With the help of Durbin-Watson statistical criteria, it was found that the average cotton yield in the region has an autocorrelation dependence.
State of fuel and energy resources and their rational use in the agro-industrial sector of the Republic of Uzbekistan
Authors: Mamasalieva M. I.
Published: August 2023

This article analyzes the status of the issue of rational use of fuel and energy resources of the Republic of Uzbekistan. Currently, the share of renewable energy sources in the fuel and energy balance of the country does not exceed one percent. At the same time, the potential of renewable energy sources of Uzbekistan is about 51 billion tons of oil equivalent, the technical potential of more - 179 00.0 million tons of oil equivalent.
Properties of powdered metal-ceramic materials obtained from by-products of the mining and metallurgical industry of Uzbekistan
Authors: Norkhudjayev F. R. , Mukhamedov A. A. , Guzashvili K. V. , Mirzarakhimova Z. B. , Chulliyev Z. F.
Published: August 2023

One of the actual problems of production is the use of various waste products, in particular metallurgical. The method of powder metallurgy allows the use of waste from metallurgical industries. This is used in this work to obtain an antifriction porous material based on iron and copper. Iron and copper powders obtained at the Almalyk Mining and Metallurgical Combine by restoring iron and copper scale of metallurgical plants are used. Pyrite, a waste product of the Almalyk Mining and Metallurgical Combine, is used as an additive material. Tests have shown the possibility of manufacturing metal-ceramic iron and copper-containing antifriction alloys with pyrite additive based on local raw materials.
Retraction Note: The effect comparative evaluation of energy saving additives on the bitumen properties
Authors: Riskulov Alimjon , Sidikova Takhira , Khakimov Rovshan , Avliyokulov Jamshed
Published: August 2023

This paper has been formally retracted on ethical grounds because the article contains extensive and repeated instances of plagiarism. The authors are responsible for this mistake and apologise for it. Request approved by the proceedings Editor and the Publisher on August 2, 2023.
Improving efficiency in a distribution network with asymmetric load due to connected solar panels with a phase relationship
Authors: Sattarov Khurshid , Sapayev Mamatkarim , Suyarov Anvar , Turaev Akramjon
Published: August 2023

In the article, the distribution of symmetrical loads operating in extreme load, taking into account the total power of the consumers in the power network, was modeled by installing solar panels in apartments. As a result, as a result of the use of solar panels with a total power of 34 kW in the houses in the cable distribution network with a length of 0.444 km, a reduction of active power loss of 21382 kWh (37%) is achieved, a reduction of reactive power loss is achieved by 7309kVAR*hour (37%), the level of overloading of the cable network was 1- in the section of households, from 105% to 85%, and in the section of the last households, a decrease is achieved from 14% to 6%. In addition, it was found that the voltage drop at the ends of the apartments is not at the required level, and when the solar panels are connected, it is at the limit values.
Methodology for determining technical, economic and environmental performance of combined power plants
Authors: Kan Eduard , Mukhammadiev Muradulla , Dzhuraev Kurbon , Abduaziz Uulu Abdurauf , Shadibekova Fatima
Published: August 2023

Consideration of the feasibility of building combined power plants (CPP) based on renewable energy sources (RES) and the choice of parameters, type of equipment, layout, and design solutions is based on an assessment of economic efficiency, the indicator of which is the ratio between the required investments and the achieved technical and economic effect. An accurate assessment of economic efficiency is a rather difficult task since it is necessary to take into account a large number of factors, for example, specific features of design solutions, operating conditions of the CPP depending on the requirements of the consumer, the stochastic nature of the manifestation of energy resources, the possible mode of operation of the CPP for the needs of individual consumers and others. An approach based on the minimum cost criteria has been widely used for the economic justification of the objects under construction for a long time. In rigidly centralized economic management, such an approach based on ensuring optimal construction planning played an important role in increasing the scientific validity of economic decisions. It proceeded from the global and national economic goals of economic development. In the conditions of a free market economy, a method of evaluating the effectiveness of taking into account all the main features of it is necessary.
Research of water flow measuring device based on Arduino platform
Authors: Djalilov A. , Nazarov O. , Sobirov E. , Tasheva U. , Abdunabiyev J. , Urolov S.
Published: August 2023

The article provides information about modern methods and devices for measuring water flow in pipes in the irrigation system. To create a device suitable for an automated system for calculating water flow in pipes, and sending information about water flow via Bluetooth and GPRS module, the possibility of using the base of the Arduino platform was considered. A YF-S201 transducer was used to determine the water flow in the pipe. The article presents the experiment results based on a laboratory stand. Based on the Arduino UNO board and laptop, the measurement results were processed, as well as the remote transmission of data and their visualization on a smartphone. The linearity and error of the static characteristic of the proposed water flow detection device were investigated.
Influencing engagement angle on power parameters in flat-belt gears
Authors: Kenjayev Sirozhiddin , Yunusov Salokhiddin , Abdurakhimov Mukhammatsidik , Ahmedova Dilafruz
Published: August 2023

The article considers the ratio of forces in belt drives, proposes a calculation scheme for the forces of a flat-belt transmission [FBR], and calculates and analyzes the effect of changing the engagement angle and load on the friction coefficient. Belt drives refer to mechanical friction transmissions with a flexible connection and are used if it is necessary to transfer the load between shafts located at considerable distances. The influence of a change in the coefficient of friction of the belt on the power parameters of the transmission is considered.

The load is given in the form of a torque, which is transmitted to the belts by the circumferential force, the tension of the leading branch increases the circumferential force, and that of the driven branch decreases. Power graphs were built, and the analysis shows that the growth of α hurts the friction coefficient f. The curves have their own regularity with the value of the approximation R2. The influence of the change in the angle of engagement a on the coefficient of friction f with a change in load in the form of belt tensions F1 and F2 or F1 − F2 = Ft is considered. Combining these components, it will be possible to calculate and select rational parameters of belt drives; the maximum increase in the friction coefficient, considering the loads on the shaft and supports, allows transmitting torque with a relatively smaller angle α.
English Song-based Learning Strategies to Improve English Students’ Listening Skills of English Education Department at the University of Mataram
Authors: Abimanyu Ananda Fajar
Published: August 2023

In English, there are four skills which are reading skills, listening skills, writing skills, and speaking skills. English students have to improve their listening skills through the learning process, which has an impact on the development of student’s skills. Learning activities can change and develop students’ English skills to become more proficient and understand what they are learning. And there are several methods used in developing students’ English skills. This study investigated students’ listening skills improvement through English songs, and the purpose of this study was to determine how English songs can be used to improve the listening skills of English students. The participants of this study were seventh-semester students consisting of 21 students from 210 students in seven classes. This research method is a qualitative study, and data collection was done by distributing a questionnaire to 21 students who had taken the listening course. The results show that English songs are moderately effective in improving students’ listening skills.
A Practical Synthesis of Near-Infrared Benzannulated Xanthenoid Dyes
Authors: Li Jin , Wei Ruwei , Yang Youjun , Zhang Xiaodong , Luo Xiao , Qian Xuhong
Published: August 2023

Near-infrared dyes are sought after for their potential in biomedical applications. Benzoxanthene dyes with a non-oxygen bridging atom are expected to exhibit longer absorption and emission wavelengths than their oxygen-containing counterparts, yet their synthesis remains unaddressed. Herein, we report the first syntheses of non-oxygen-bridged benzoxanthenes starting from a 7-bromo-2-aminonaphthalene derivative, and discuss their photophysical properties as well as their potential for in vivo imaging.
Physicochemical Study, Chemical Profiling and Molecular Docking Study for Standardisation of the Homoeopathic Drug Damiana
Authors: Biswas Bibaswan , Maity Satyajit , Bhar Kaushik , Sett Sudeshna , Kumar G.V. Narasimha
Published: August 2023

Introduction Damiana has been used as aphrodisiac in ethnomedicine for centuries. However, the use of Damiana in homeopathy is diverse, e.g. for migraine treatment of, amenorrhoea, spermatorrhoea, urinary tract infection and prostate related issues. However, this medicinal plant is non-native to India. Hence, it is imperative to investigate the quality of the medicine samples available and prepared in India. Hence, we undertook in-depth chemical analysis of the raw drugs and the commercially available samples of this medicine.

Materials and Methods The reported chemical study includes determination of the physicochemical parameters of the raw drug involving, foreign matter, loss on drying, extractive values in different solvents, ash values total fixed oil and total volatile oil. Also, the study includes the analysis of the in-house and commercial mother tinctures consisting of, pH, organoleptic parameters, total solids, total phenol content, ultraviolet absorption spectroscopy and high performance thin layer chromatography. Phytochemical screening of the mother tinctures and extracts of the raw drugs in different solvents was done. A preliminary molecular docking study was done to evaluate the applicability of apigenin as the homoeopathy-specific marker.

Result In-house mother tincture, mother tinctures from Indian and multinational companies show similar quality. Molecular docking revealed that apigenin may be a good candidate for homoeopathy-specific marker.

Conclusion Our study provides pharmacopoeial standards which show that even for exotic plants the quality of mother tinctures from Indian and international companies is similar.
Molecular Epidemiology of HCV RNA Genotype-3 in Dhaka City, Bangladesh
Authors: Rahman Md Arifur , Islam Md Monirul , Ali Md Eunus , Islam Mohammad Ariful , Afroze Farhana , Hossain Mohammad Shamim , Rus'd Ahmed Abu
Published: August 2023

Hepatitis C virus (HCV) is a causative agent that causes chronic liver diseases worldwide. It is a little, enclosed, single-stranded ribonucleic acid (RNA) virus. The recognition of the pathogenic HCV genotype is critical for the remedy of its sufferers. The aim of this study was to identify the HCV RNA genotype to decide the correct treatment of hepatitis C positive sufferers in Bangladesh. Blood samples were collected from 390 individuals and isolated RNA (60 µg) from blood plasma. Extracted RNA was used for quantitative HCV RNA, and complementary DNA (cDNA) was prepared by polymerase chain reaction (PCR) conducted by reverse transcriptase enzyme. This cDNA amplified in multiplex by RT-PCR, which was performed with specific set of primers. The HCV RNA genotype was detected 297 of 390 patients. Of the 390 test samples, 200 (51.28%) samples were from males and 190 (48.71%) were from females, with age ranging from 5 to 78 years. In all, 166 of 200 male samples and 131/190 female samples were found positive for HCV. Of these 390 participants included in the study, 213 (54.61%) were identified as genotype 3 positive, 78 (20%) as genotype 1 positive, 6 (1.53%) as genotype 6 positive, and the remaining 93 (23.85%) samples were unclassified due to low/undetected viral load. In this study, we detected the highest percentage (30.89%) of genotype 3 HCV in patients aged 51 to 60 years. The results suggested that genotype 3 HCV is frequently present in Bangladesh and it is usually responses better to interferon therapy. However, genotype 1 and 6 HCV have also been found circulating in this country, which demands longer treatments and effective control measures.
Covid Antibody Titers in Cancer Patients Following Vaccination with ChAdOx1 nCOV-19 Vaccine
Authors: Chavan Ashish , Shriyan Bharati , Chavan Preeti , Shirsat Aditi , Gavhane Umakant , Pillai Babu , Bhat Vivek , Dhamne Chetan , Gota Vikram
Published: August 2023

Covid-19 has led to significant mortality worldwide, with an increased risk in cancer patients. Vaccination provides significant protection against the infection. The study focuses on the immunogenicity and effectiveness of ChAdOx1 nCoV-19 vaccine in cancer patients within a real-world setting. Blood samples for measuring Covid antibody titers against the receptor binding domain were collected according to a convenient sparse sampling strategy in a real-world setting, with the days of the collection coinciding with their hospital appointment. The antibody titers between different groups were analyzed descriptively. A total of 56 patients were enrolled in the study. There was no apparent effect in antibody titers between patients with solid tumors and hematological malignancies (mean ± standard deviation [SD]: 36.80 ± 41.18 vs. 52.02 ± 26.27), among patients who were undergoing chemotherapy, immunotherapy, or local therapy (mean ± SD: 42.50 ± 44.46 vs. 50.06 ± 51.39 vs. 28.70 ± 25.03), and in patients with up to 90 days and more than 90 days' interval between their last treatment and date of vaccination (mean ± SD: 38.96 ± 42.66 vs. 40.51 ± 38.65). Additionally, there were only 2/56 patients with breakthrough infection, which points out the effectiveness of this vaccine in cancer patients. The ChAdOx1 nCoV-19 vaccine has activity in cancer regardless of the tumor type, type of treatment, or time from the last treatment.
Health Disparity Curricula for Ophthalmology Residents: Current Landscape, Barriers, and Needs
Authors: Carvajal Nicole , Lopez Justin , Ahmad Tessnim R. , Maru Johsias , Ramanathan Saras , Seitzman Gerami D. , Padmanabhan Sriranjani , Parikh Neeti
Published: August 2023

Background Social determinants of health play a critical role in visual health outcomes. Yet, there exists no structured curriculum for ophthalmology residents to identify and address health disparities relevant to eye care or no a standard assessment of health disparities education within ophthalmology residency programs. This study aims to characterize current health disparity curricula in ophthalmology residency programs in the United States, determine resident confidence in addressing health disparities in the clinical setting, and identify perceived barriers and needs of program directors (PDs) and residents in this area.

Design This was a cross-sectional survey study.

Methods A closed-ended questionnaire with comments was distributed to the Accreditation Council for Graduate Medical Education-accredited ophthalmology residency PDs and residents in April 2021 and May 2022. The questionnaire solicited characteristics of any existing health disparity curricula, PD and resident perceptions of these curricula, and residents' experience with and confidence in addressing health disparities in the delivery of patient care.

Results In total, 29 PDs and 96 residents responded. Sixty-six percent of PDs stated their program had a formal curriculum compared to fifty-three percent of residents. Forty-one percent of PDs and forty-one percent of residents stated their program places residents in underserved care settings for more than 50% of their training. Most residents (72%) were confident in recognizing health disparities. Sixty-six percent were confident in managing care in the face of disparities and fifty-nine percent felt they know how to utilize available resources. Residents were most concerned with the lack of access to resources to help patients. Forty-five percent of PDs felt the amount of time dedicated to health disparities education was adequate. Forty-nine percent of residents reported they felt the amount of training they received on health disparities to be adequate. The top barrier to curriculum development identified by PDs was the availability of trained faculty to teach. Time in the curriculum was a major barrier identified by residents.

Conclusions Roughly half of ophthalmology residency programs who responded had a health disparity curriculum; however, both PDs and residents felt inadequate time is dedicated to such education. National guidance on structured health disparity curricula for ophthalmology residents may be warranted as a next step.
The Risk of Incident Venous Thromboembolism Attributed to Overweight and Obesity: The Tromsø Study
Authors: Frischmuth Tobias , Tøndel Birgitte G. , Brækkan Sigrid K. , Hansen John-Bjarne , Morelli Vânia M.
Published: August 2023

Background Obesity is a well-established risk factor for venous thromboembolism (VTE). However, data on the proportion of incident VTEs attributed to overweight and obesity in the general population are limited.

Objective To investigate the population attributable fraction (PAF) of VTE due to overweight and obesity in a population-based cohort with repeated measurements of body mass index (BMI).

Methods Participants from the fourth to seventh surveys of the Tromsø Study (enrolment: 1994–2016) were followed through 2020, and all incident VTEs were recorded. In total, 36,341 unique participants were included, and BMI measurements were updated for those attending more than one survey. BMI was categorized as <25 kg/m2, 25–30 kg/m2 (overweight), and ≥30 kg/m2 (obesity). Time-varying Cox regression models were used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs). The PAF was estimated based on age- and sex-adjusted HRs and the prevalence of BMI categories in VTE cases.

Results At baseline, the prevalence of overweight and obesity was 37.9 and 13.8%, respectively. During a median follow-up of 13.9 years, 1,051 VTEs occurred. The age- and sex-adjusted HRs of VTE were 1.40 (95% CI: 1.21–1.61) for overweight and 1.86 (95% CI: 1.58–2.20) for obesity compared with subjects with BMI <25 kg/m2. The PAF of VTE due to overweight and obesity was 24.6% (95% CI: 16.6–32.9), with 12.9% (95% CI: 6.6–19.0) being attributed to overweight and 11.7% (95% CI: 8.5–14.9) to obesity. Similar PAFs were obtained in analyses stratified by sex and VTE subtypes (provoked/unprovoked events, deep vein thrombosis, pulmonary embolism).

Conclusion Our findings indicate that almost 25% of all VTE events can be attributed to overweight and obesity in a general population from Norway.
Double variational principle for mean dimensions with sub-additive potentials
Authors: Wang Yunping , Chen Ercai
Published: August 2023

In this paper, we introduce mean dimension quantities with sub-additive potentials. We define the mean dimension and mean metric dimension with sub-additive potentials and establish a double variational principle for sub-additive potentials.
Rapid and ultrasensitive detection of mpox virus using CRISPR/Cas12b-empowered graphene field-effect transistors
Authors: Wang Li , Xu Chang , Zhang Shaohui , Chen Shang , Wang Hao , Duan Zhaojun , Al-Hartomy Omar A. , Wageh Swelm , Wen Xiaosha , Liu Yi , Lin Yi , Pu Huijie , Xie Zhongjian , Liu Quan , Zhang Han , Luo Dixian
Published: August 2023

Mpox is an infectious viral disease, and, as of January 12, 2023, about 84 560 distinct cases have been detected, involving about 110 countries since May 2022. Most clustered regularly interspaced short palindromic repeat (CRISPR)-based detection methods require long assay time because of the pre-amplification to target nucleic acids. Herein, we designed a new prototypal mpox biosensor that allows amplification-free nucleic acid detection by combining CRISPR/Cas12b system and ultrasensitive graphene field-effect transistor (gFET). The CRISPR/Cas12b–gFET enabled the detection of the mpox virus (MPXV) DNA targets at a sensitivity of ∼1 aM within about 20 min. We designed several sgRNAs to recognize the target genes of MPXV and then Cas12b protein cleaved the target genes to form a double-strand break. The specificity of sgRNAs of MPXV designed was verified among other homologous Orthopoxviruses, and the sgRNA could distinguish between recent 2022 MPXV and West African MPXV with the mutation site, showing its potential application in MPXV detection. Thus, the demonstrated CRISPR–gFET detection technology could serve as a sensitive and rapid diagnostic tool for MPXV and other DNA viruses in the future.
Energetics of phase transitions in homogeneous antiferromagnets
Authors: Hu M. , Hoefer M. A. , Donahue M. J.
Published: August 2023

Spatially uniform static phases in an antiferromagnet (AFM) at 0 K accessible by varying an external magnetic field along the anisotropy axis are investigated. Using the macrospin model, the energy contributions are comprised of the external field, effective anisotropy, and spatially homogeneous AFM exchange. The critical energy configurations are fully cataloged, and local energy concavity is used to identify stable states. Relative energy levels are taken into account to classify phase transitions. Phase diagrams for energetic stability and phase transitions are provided in terms of the strength of the applied field and the ratio between anisotropy and the AFM exchange. Two nonstandard critical energy states are identified as energy saddle points so are not stable but function as energy barriers between multiple stable states. The results determine thermal switching rates and suggest interesting AFM textures and solitons.
Convergence rates to the planar stationary solution to a 2D model of the radiating gas on half space
Authors: Zhang Minyi , Zhu Changjiang
Published: August 2023

This paper is concerned with the asymptotic stability of a planar stationary solution to an initial-boundary value problem for a two-dimensional hyperbolic–elliptic coupled system of the radiating gas on half space. We show that the solution to the problem converges to the corresponding planar stationary solution as time tends to infinity under small initial perturbation. This result is proved by the standard L2-energy method and the div–curl decomposition. Moreover, we prove that the solution (u, q) converges to the corresponding planar stationary solution at the rate t−α/2−1/4 for the non-degenerate case and t−1/4 for the degenerate case. The proof is based on the time and space weighted energy method.
Spatial structure of the non-integrable discrete defocusing Hirota equation
Authors: Ma Liyuan , Fang Miaoshuang , Song Haifang , Zhou Jiali
Published: August 2023

In this paper, we investigate the spatial property of the non-integrable discrete defocusing Hirota equation utilizing a planar nonlinear discrete dynamical map method. We construct the periodic orbit solutions of the stationary discrete defocusing Hirota equation. The behavior of the orbits in the vicinity of the special periodic solution is analyzed by taking advantage of the named residue. We characterize the effects of the parameters on the aperiodic orbits with the aid of numerical simulations. A comparison with the non-integrable discrete defocusing nonlinear Schrödinger equation case reveals that the non-integrable discrete defocusing Hirota equation has more abundant spatial properties. Rather an interesting and novel thing is that for any initial value, there exists triperiodic solutions for a reduced map.
Stability and bifurcation analysis of Alzheimer’s disease model with diffusion and three delays
Authors: Li Huixia , Zhao Hongyong
Published: August 2023

A reaction–diffusion Alzheimer’s disease model with three delays, which describes the interaction of β-amyloid deposition, pathologic tau, and neurodegeneration biomarkers, is investigated. The existence of delays promotes the model to display rich dynamics. Specifically, the conditions for stability of equilibrium and periodic oscillation behaviors generated by Hopf bifurcations can be deduced when delay σ (σ=σ1+σ2) or σ3 is selected as a bifurcation parameter. In addition, when delay σ and σ3 are selected as bifurcation parameters, the stability switching curves and the stable region are obtained by using an algebraic method, and the conditions for the existence of Hopf bifurcations can also be derived. The effects of time delays, diffusion, and treatment on biomarkers are discussed via numerical simulations. Furthermore, sensitivity analysis at multiple time points is drawn, indicating that different targeted therapies should be taken at different stages of development, which has certain guiding significance for the treatment of Alzheimer’s disease.
NLSI: An innovative method to locate epidemic sources on the SEIR propagation model
Authors: Peng Shui-Lin , Wang Hong-Jue , Peng Hao , Zhu Xiang-Bin , Li Xiang , Han Jianmin , Zhao Dandan , Hu Zhao-Long
Published: August 2023

Epidemics pose a significant threat to societal development. Accurately and swiftly identifying the source of an outbreak is crucial for controlling the spread of an epidemic and minimizing its impact. However, existing research on locating epidemic sources often overlooks the fact that epidemics have an incubation period and fails to consider social behaviors like self-isolation during the spread of the epidemic. In this study, we first take into account isolation behavior and introduce the Susceptible-Exposed-Infected-Recovered (SEIR) propagation model to simulate the spread of epidemics. As the epidemic reaches a certain threshold, government agencies or hospitals will report the IDs of some infected individuals and the time when symptoms first appear. The reported individuals, along with their first and second-order neighbors, are then isolated. Using the moment of symptom onset reported by the isolated individuals, we propose a node-level classification method and subsequently develop the node-level-based source identification (NLSI) algorithm. Extensive experiments demonstrate that the NLSI algorithm is capable of solving the source identification problem for single and multiple sources under the SEIR propagation model. We find that the source identification accuracy is higher when the infection rate is lower, and a sparse network structure is beneficial to source localization. Furthermore, we discover that the length of the isolation period has little impact on source localization, while the length of the incubation period significantly affects the accuracy of source localization. This research offers a novel approach for identifying the origin of the epidemic associated with our defined SEIR model.
Carrier optical vortex interferometer using segmentation demodulation method for dynamic measurement of axisymmetric surface deformation
Authors: Dong Jingtao , Xie Liyuan , Wang Shuo , Zhao Enxi , Li Yangyang , Tian Zhipeng
Published: August 2023

The dynamic measurement of surface deformation with an axisymmetric profile at nanometer- to micrometer-scale is of great interest in understanding micromechanical and thermophysical dynamics. We propose a carrier optical vortex interferometer (COVI) to measure such surface deformation dynamically by segmentation demodulation of the petal-like interferogram that is produced by the coaxial superposition of conjugated p-radial order Laguerre–Gaussian beams. Specifically, a rotating chopper placed at the exit of the interferometer introduces a carrier frequency in the absence of surface deformation. A camera placed behind the chopper uses a multi-ring segmentation detection scheme to produce a Doppler shift relative to the carrier frequency at the radius of each ring in the presence of axisymmetric surface deformation. Locating the Doppler shifts gives the surface deformation velocities at those radii. Thus, the dynamic surface deformation profile can be obtained by integrating the velocities over time. We reveal the basic principles of the carrier frequency and the Doppler shifts in the COVI theoretically. As a proof-of-concept, an external force-induced axisymmetric mechanical surface deformation is measured dynamically to demonstrate the validity of the COVI. The results show that the measurement error of the surface deformation velocity is within (−2.1, 1.1 nm/s) for the velocity ranging from 20 to 86 nm/s. The lower limit of the measurable velocity can reach 20 nm/s. The measurement error of the surface deformation profile is less than 2.5 nm for the amplitude of the surface deformation of 500 nm.
CEBoosting: Online sparse identification of dynamical systems with regime switching by causation entropy boosting
Authors: Chen Chuanqi , Chen Nan , Wu Jin-Long
Published: August 2023

Regime switching is ubiquitous in many complex dynamical systems with multiscale features, chaotic behavior, and extreme events. In this paper, a causation entropy boosting (CEBoosting) strategy is developed to facilitate the detection of regime switching and the discovery of the dynamics associated with the new regime via online model identification. The causation entropy, which can be efficiently calculated, provides a logic value of each candidate function in a pre-determined library. The reversal of one or a few such causation entropy indicators associated with the model calibrated for the current regime implies the detection of regime switching. Despite the short length of each batch formed by the sequential data, the accumulated value of causation entropy corresponding to a sequence of data batches leads to a robust indicator. With the detected rectification of the model structure, the subsequent parameter estimation becomes a quadratic optimization problem, which is solved using closed analytic formulas. Using the Lorenz 96 model, it is shown that the causation entropy indicator can be efficiently calculated, and the method applies to moderately large dimensional systems. The CEBoosting algorithm is also adaptive to the situation with partial observations. It is shown via a stochastic parameterized model that the CEBoosting strategy can be combined with data assimilation to identify regime switching triggered by the unobserved latent processes. In addition, the CEBoosting method is applied to a nonlinear paradigm model for topographic mean flow interaction, demonstrating the online detection of regime switching in the presence of strong intermittency and extreme events.
Phototransferred thermoluminescence of calcite: Analysis and mechanisms
Authors: Chithambo M. L.
Published: August 2023

Phototransferred thermoluminescence (PTTL) induced from natural calcite using 470, 525, and 405 nm illumination is reported. We consider the measurement and analysis of time-response profiles, the dependence of PTTL intensity on the sample temperature during illumination to induce phototransfer, the role of deep electron traps, and discuss mechanisms for phototransfer in calcite. The conventional TL glow curve is a complex collection of closely overlapping glow peaks, but there are three stand-out ones near 90, 210, and 330 °C, denoted as I–III. These are reproduced under phototransfer. The dependence of PTTL intensity on illumination can be properly described by systems of acceptors and donors, where the number of the latter depends on the preheating temperature. The systems have been analyzed by phenomenological and kinetics models. The intensity of the PTTL is influenced by the illumination temperature, and the attendant thermal assistance and thermal quenching have been quantified. Electronic processes relevant to the PTTL of calcite are thought to involve the relaxation of (CO3)2− and Mn2+ ions. An anomalous increase in PTTL induced from deep electron traps has been deduced to be a possible result of quantum tunneling of charge between (CO3)3− stabilized close to Mn3+ cations.
Effects of lattice distortion and amount of d electrons on the pressure-driven structural phase transition in ZnO: A comparative study of V-, Mn-, and Co-doped ZnO
Authors: Lin Chih-Ming , Tseng Yu-Chin , Tsai Yi-Jia , Lin Yu-Sheng , Jian Sheng-Rui , Chuang Yu-Chun , Juang Jenh-Yih
Published: August 2023

The pressure-driven phase transition from fourfold würtzite (B4) to sixfold coordinated rock salt (B1) structure in ZnO, in particular in transition metal (TM) doped ones, exhibited very scattered results and remained as an outstanding issue. The in situ angle-dispersive x-ray diffraction revealed that TM doping can result in significant reduction on the onset pressure at which the pressure-driven B4-to-B1 phase transition starts to emerge, albeit the transition path appeared to be very much dependent on the doping transition metal element. Systematic comparisons on a series of V-, Mn-, and Co-doped ZnO materials indicated that, in addition to ionic sized difference-induced lattice distortion, the amount of the 3d electrons carried by the doped TM atom may also play a prominent role in the underlying mechanism of the pressure-driven phase transition. Specifically, the existence of 3d electrons may have resulted in increased screening of the Coulomb forces between the cations at increasing pressure, leading to significant softening of the c44 and c66 elastic constants, which, in turn, lowers the onset pressure in triggering the B4-to-B1 phase transition in ZnO. Our results also indicate that the initial lattice distortion induced by the ionic size difference may change the landscape of energy barrier and alter the phase transition path.
Enhanced plasma current spike formation due to onset of 1/1 kink-tearing reconnection during a massive gas injection process
Authors: Zeng Shiyong , Zhu Ping , Ren Haijun
Published: August 2023

The formation of the plasma current spike at the end of the thermal quench (TQ) phase is studied systematically, which is found to strongly correlate with the onset of the 1/1 kink-tearing reconnection only in the simulation results presented here. The magnetohydrodynamic activity on the q = 1 surface plays a critical role in the spike formation and the disruption process. In particular, when the safety factor in the magnetic axis q0 exceeds 1, the plasma major disruption transits into successive minor disruptions, and the start of the TQ phase is delayed.
A framework for synthetic power system dynamics
Authors: Büttner Anna , Plietzsch Anton , Anvari Mehrnaz , Hellmann Frank
Published: August 2023

We present a modular framework for generating synthetic power grids that consider the heterogeneity of real power grid dynamics but remain simple and tractable. This enables the generation of large sets of synthetic grids for a wide range of applications. For the first time, our synthetic model also includes the major drivers of fluctuations on short-time scales and a set of validators that ensure the resulting system dynamics are plausible. The synthetic grids generated are robust and show good synchronization under all evaluated scenarios, as should be expected for realistic power grids. A software package that includes an efficient Julia implementation of the framework is released as a companion to the paper.
Effects of protuberant structure on coalescence-induced jumping of droplets on superhydrophobic surfaces
Authors: Wang Yuhang , Rohlfs Wilko , Kneer Reinhold
Published: August 2023

The coalescence-induced jumping of droplets on superhydrophobic surfaces is useful in engineering-related applications to enhance condensation-based heat transfer, self-cleaning, and anti-icing and, thus, has attracted extensive attention in research. Some researchers have claimed that superhydrophobic surfaces with protuberant structures can yield droplets with a higher jumping velocity. While the structure of the surface influences droplet dynamics, the concomitant energy transition also needs to be considered. The effects of the geometry on the mechanism of jumping and the energy transition need to be investigated. In this paper, an improved volume-of-fluid method is verified based on experiments and then applied to simulate the jumping behaviors of droplets on superhydrophobic surfaces with cuboid protuberant structures. The effects of repulsion caused by the contributions of the surface tension and the superhydrophobicity of the protuberance are crucial to enhancing the jumping of the droplets. The forces due to them provide a thrust oriented in the direction of jumping of the droplets to increase the value of the positive energy term, while reducing the area and duration of contact between the droplet and the substrate to reduce the negative dissipation term and enhance the efficiency of energy conversion. Surprisingly, an excessively tall structure leads to a sustainable increase in the velocity of jumping of the droplets under the effects of repulsion and the Laplace pressure after piercing the liquid bridge. The work here provides guidance to optimally combine a superhydrophobic substrate with special structures to enhance the jumping of droplets.