bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficiency of use of magnetic water in drip irrigation of cotton
Authors: Ergashova Dinara , Kasymbetova Saltanat
Published: January 2023

The article presents the results of field research conducted on a cotton field of drip irrigation using magnetic irrigation water. The research aimed to study the effect of magnetic water on the growth, development, and increase in cotton yield in the meadow-serozem soil-reclamation conditions of the Chirchik-Akhangaran valley.

The authors provide an overview of the designs and the principle of operation of various magnetic devices used for irrigation in domestic and world practice.

In order to save irrigation water and study the effect on the growth, development, and increase in cotton yield, field studies were carried out using magnetized water during drip irrigation of cotton.
Increasing environmental safety, increasing service life of ice units and assembly and saving fuel consumption through application of multifunctional fuel additives
Authors: Tursunov Sherali , Khikmatov Ravshan
Published: January 2023

This article presents the results of studies on the use of multifunctional diesel fuel additives, which will reduce harmful emissions of NOx, COx, SOx into the environment by improving the operational and environmental characteristics of the original fuel and converting harmful emissions of nitrogen oxides, carbon, and sulfur into useful energy, optimize fuel consumption and increase the performance and service life of ICE units and components without changing the indicators (requirements) of State Standard for fuel, achieve diesel fuel savings of 3-5% of the total fuel consumed.
Computerized system of acoustic-emission control of metal structures
Authors: Sagatov Miraziz , Komilova Kholida , Maksudov Rustam , Kucharov Olimzhon
Published: January 2023

Research on the problems of creating effective control and diagnostic systems allows us to single out the following areas: the development of the theory and methods for diagnosing and predicting the strength and reliability of structures, theoretical and experimental studies of fracture processes, and the corresponding changes in characteristics and parameters, i.e., carriers of information about the processes occurring in the material during destruction; creation of information-measuring systems designed to register and analyze the information necessary to resolve the issue of the state of the structure; development of software for measuring equipment, including not only the main programs for generating and processing incoming information but auxiliary subroutines that provide information compression, increase the reliability of measurement results, defect recognition, decision making. The article is devoted to the methods of acoustic-emission control of metal structures and developing a computerized system for its implementation. The basics of organizing a software-algorithmic system for locating and processing acoustic emission signals are considered, including methods for discretizing models of sensors and acoustic emission signals, which make it possible to obtain computational schemes such as a digital filter that provide effective algorithmic implementation; description of fragments of an experimental software-algorithmic system for processing acoustic emission signals, illustrating the principle of constructing software tools in an arbitrarily chosen computing area, the structure of the software organization of computational processes for locating an acoustic emission signal, which ensures the construction of the corresponding subsystem of a computer complex for acoustic-emission control, both in single-antenna and in a multi-antenna version.
Analytical conclusions and proposals for technical condition and effective use of facilities on Tashkent magistral canal
Authors: Kadirov Odiljon , Khasanov Khojiakbar
Published: January 2023

The socio-economic development of the Tashkent region (Uzbekistan) depends largely on natural resources, especially water resources, as in other regions. One of the canals that supply water to the Tashkent province is the Tashkent magistral canal (TMC). In terms of size, the second of the canals receives water from the left bank of the Chirchik River. The TMC has been 82 years since its start of use. Hydrotechnical facilities on the TMC are typical of the II class. There are many hydrotechnical facilities on the canal: one main structure, four water dampening facilities, two destructive water discharges, four duckers in the canal, 45 water dischargers, one waterfall, seven under-canal duckers, two pipes under the canal, nine aqueducts, nine canal access, thirteen road bridges, one railway bridge, one pedestrian bridge. This article presents the technical condition of the TMC and its hydrotechnical facilities and recommendations developed based on the technical condition. On April 9-13, 2022, field observation work was carried out to study the technical condition of the TMC and hydrotechnical facilities. It reviewed the availability of technical documents of TMC facilities, instructions for their use, information on maintenance of mechanical equipment, working drawings, previous inspection reports, and other materials. In addition, the conclusions of the inspection carried out by the State Inspection "Davsuvkhujalikzorat" and the results of the technical inspections carried out by the employees of the TMC administration and project parameters of water facilities were studied.
Consumption of Irrigation Pumps Pumping Water with a High Content of Mechanical Impurities
Authors: Kan Eduard , Vatin Nikolay
Published: January 2023

The water pumped by reclamation stations of the Republic of Uzbekistan contains many mechanical impurities. This negatively affects the operation of pumping units. There is a decrease in the operating parameters of the pumping unit and the associated increase in electricity consumption. Analysis of the alluvial regime of the main water sources of large pumping stations shows that the sediment concentration can reach values of 15-20 kg/m3 and, on average, up to 8-10 kg/m3 (i.e., exceed the permissible values according to the technical requirements for centrifugal pumps by 2-3 times). Based on the consideration of a two-phase liquid model (pure water and mechanical impurities) and formulas for determining the useful power, a dependence is derived to determine the magnitude of the increase in power consumption. According to this dependence, a graph of the dependence of the increase in the value of the required useful power depending on the concentration of mechanical impurities in the pumped water is constructed, which can be applied in practice during the operation of irrigation pumping stations. The results of a quantitative analysis of the influence of the content of mechanical impurities in the pumped water on the value of the pump's useful power showed that with average turbidity of the pumped water of 10 kg/m3, the overspending of electricity would be 1.75%. This is of great practical importance for the machine water lifting of the Republic of Uzbekistan (the main consumer of electricity in the agricultural sector), and the results can be used to develop an energy-saving strategy in the field of operation of irrigation pumping stations.
Theoretical models and dependences for calculating intensity of hydroabrasive wear of pump working parts
Authors: Uralov Bakhtiyor , Berdiev Shavkat , Rakhmatov Mahmud , Vokhidov Oybek , Maksudova Lyudmila , Raimova Iqboloy
Published: January 2023

The paper presents the results of a theoretical and experimental study of the wear intensity of the elements of the flow part of centrifugal and axial pumps. Theoretical formulas recommended by various authors, obtained for models with flat samples based on energy theory, do not consider the features of hydraulic machines. Considering the movement of a solid particle in the interblade channels of the impellers of centrifugal and axial pumps, we chose design schemes that correspond to hydraulic and physical wear processes. The analysis shows that the action of centrifugal and inertial forces in the interblade channel of the impellers of centrifugal and axial pumps results in the separation and redistribution of solid particles in the flow. As a result, in centrifugal pumps at the end of the blade and axial pumps at the end gap of the impeller, the local concentration of solid particles increases compared to the average. The paper also provides dependencies for calculating the intensity of hydroabrasive wear of pump working parts.
Reducing vibration of pumping units of reclamation systems
Authors: Ergashev Rustam , Bekchanov Fakhriddin , Musaev Sharof , Saydullaev Sirojiddin , Kholbutaev Boybek
Published: January 2023

The article presents the results of scientific research on the operation of pumping equipment at reclamation pumping stations. In pumping stations, more and more attention is being paid to measures to maintain the reliability and efficiency of pumping units and reduce the negative impact of factors of various origins. One of the most significant factors affecting the service life of the equipment is the increased vibration of the pumping unit. According to the analysis of failures of pumping equipment at pumping stations in Uzbekistan for 2010-2021, more than 40% of the pump stops occurred due to increased vibration. The most common cause of vibration of pumping equipment is waterjet and cavitation wear of the impeller, destruction of seals, wear, and temperature rise of the bearing. The greatest vibration occurs when the equipment is operated in heavy and non-optimal modes. As a result of the generalization of the research results, active methods and means of reducing the vibration of pumping units were identified.
Evaluation of sedimentation of water reservoirs with modern technologies
Authors: Xoshimov Sardor , Atakulov Dinislam , Yalgashev Obit , Komilov Sheroz , Boykulov Jurabek
Published: January 2023

When dams are built, sedimentation accumulation starts in high-fuzzy; after filling of dead volume happens, blurring of useful volume, and the efficiency of the reservoir decreases. In this research, the Chartak reservoir in the Namangan region. In this study, the ArcGIS application was used with the ArcMap program. Originally Sentinel 2 Satellite images were downloaded free of charge from Glo Vis US official website. The unstable reservoirs were selected for the length of the reservoir. For each reservoir, the dependence of the water level on the flow rate was calculated, thus analyzing the sediment movement. The research results showed that 10 control points were taken, where Q was the same. In the first control point, in which all value was a bit lower than others, Q was 5, followed by 310 in B, 3.4 in H, omega had 1081.3, and 4.6 in ϑ.
The Kabul River Basin - the source of the Naglu and other reservoirs
Authors: Bazarov Dilshod , Ahmadi Mahfouz , Ghayur Abdulatif , Vokhidov Oybek
Published: January 2023

The article is devoted to the assessment and study of the Kabul river basin fed by 7 existing (Jabal-Saraj, Karga, Mahipar, Naglu, Sarubi, and Darunta) and numerous planned (including Gulbahor, Baghdara, Sarubi II, Kunar I, Kunar II, Shatut) reservoirs. The article discusses the Kabul basin's annual precipitation, land cover, and runoff. In addition, it sheds light on soil erosion and the concentration of river and reservoir sedimentation in the Kabul River Basin. Recommendations are also given for solving the problem of soil erosion and the siltation of reservoirs.

There is very little data on the Kabul River and its basin due to the lack of detailed hydrological data. Most of the hydrological and meteorological posts did not function or were destroyed during the crisis in the country for about two decades, which led to little or no information on the river's hydrology during this period. Because of this problem, many organizations working in basin water management and designing new hydraulic structures face difficulties in properly planning and designing new hydraulic structures and reservoirs. As a result, most researchers, planners, and designers use old data with a limited observation period, which is insufficient for adequate design and planning of hydraulic structures and other basin development projects.

Due to four decades of unrest in the country, the watersheds of the Kabul Basin have been used without any rules or management, resulting in land degradation and watershed erosion.

Three main problems, namely overgrazing in rangelands, rain-fed fields, and deforestation, have caused land degradation in the basin. In addition, the situation has been aggravated by the cutting of bushes for fuel in hilly and semi-hilly areas. The basin is overpopulated, and there are many industries in the major cities of the basin, which contributes to water pollution in the Kabul river. Despite water availability, due to a lack of proper planning, the major cities in the basin cannot use the basin's water for domestic needs. In cities like Kabul and Jalalabad, people mainly use groundwater, resulting in the continuous sinking of the groundwater level. For the proper management and development of the Kabul river basin, much work needs to be done, which may yield promising results for developing the country's economy and improving the environment in the Kabul basin region.
Experimental studies of frequency of rotation of smooth rotating disk with coaxial-lateral air flow
Authors: Utepov Burxon , Khaydarov Tuygun , Rajabov Nurmamat , Murtazayeva Gulnoza , Tulaganov Bakhtiyor , Avliyakulov Mirzoolim
Published: January 2023

The article presents methods for determining the main parameters of a rotating atomizer sprayer. The choice of research methodology is justified based on the general pattern of liquid atomization by rotating atomizers, taking into account the influence of the air flow on them. The main indicators affecting the sprayed drops' dispersal are the air flow rate and the rotational speed of the pneumatic disk atomizer. Therefore, the correct choice of the method for determining the rotational speed ω of a pneumatic disk atomizer makes it possible, at a constant air flow rate, to obtain the required median-mass diameter of the atomized droplets. To obtain a high-quality air-droplet flow, there must be a combination between the initial speed of the main drops discharged from the spray disk's periphery and the fan installation's air flow speed.
Development of new pole-changing winding for lifting and transport mechanisms
Authors: Bobojanov M.K. , Rismukhamedov D.A. , Tuychiev F.N. , Shamsutdinov Kh.F.
Published: January 2023

In many industries, lifting and transport machines are used, particularly cranes, conveyors, and hoists. Taking into account their wide prevalence and large installed capacity, as well as the complexity of the operating mode, special attention is paid to the creation of new energy- and resource-saving electric drives that facilitate the start-up process and ensure accurate stopping of highly inertial lifting and transport mechanisms. In this direction, one of the priority tasks is the development of two-speed pole-changing motors that meet the requirements of the electric drive of lifting and transport mechanisms. Based on the method of "Discretely-given spatial functions", a pole-changing winding was obtained for a ratio of 1/5 poles at 30 slots of the stator. Analysis of the electromagnetic properties of the developed pole-changing winding showed that, compared with a close analog, the differential scattering coefficient on the p=1 side of the pole decreases from 1.7% to 1.3%, and on the p=5 side of the pole decreases from 15.9% to 9.7%, and also in the picture of the magnetomotive force, the presence of higher harmonic ones on the side of the first velocity decreases up to 6%, and from the second speed up to 20%.
Automatic control of active ventilation systems in agricultural products storage facilities
Authors: Yakubov Sabir , Isakov Abdusaid , Pirova Rashida , Shadmanova G.
Published: January 2023

The article recommends automatic control of active ventilation systems in agricultural product storage facilities. The search for rational solutions for ventilation, heating, and automatic control systems (ACS) that improve product storage quality and methods and means of storage is considered.

As a result of the analysis of the requirements for air-cooling storage units that operate for no more than 25 days per annual storage cycle, it was proved that refrigerating arrangements that are based on the principle of operation of vortex energy separators - vortex tubes (VT) meet these requirements most fully. In terms of temperature effect, the VT is inferior to the expander by 1.3 ... 1.5 times, in terms of cooling capacity by 3.0 ... 3.5 times. Compared to the throttling process, vortex tubes, when operating in air, are about 30 times better in terms of temperature effect and 15 times better in terms of cooling capacity.
Kinematic mode of operation of potato harvester auger
Authors: Mamatov Farmon , Mirzaev Bakhadir , Rustamova Nigora , Razzokov Тura , Hamroev Obid
Published: January 2023

The digging work parts of modern potato harvesters, when working on loamy soils with low humidity, do not meet the agrotechnical requirements. Modern machines should perform pruning, lifting, and moving the potato bed layer to the separating organs without unloading and collapsing with the least energy consumption, losses, and damage to tubers. The authors proposed combined digging work parts with passive plowshares and active augers. The purpose of the study is to substantiate the operating mode of the potato harvester auger. The basic principles and methods of classical mechanics, mathematical analysis, and statistics were used in this study. Based on theoretical studies, analytical dependences for determining the operating mode of the auger are obtained. To ensure pruning, lifting, and moving of the tuberous, the kinematic mode indicator should be in the range of 4.08 - 4.15.
Improvement of the out-of-furnace steel treatment technology for improving its mechanical properties
Authors: Toirov Otabek , Tursunov Nodirjon , Alimukhamedov Shavkat , Kuchkorov Lochinbek
Published: January 2023

The problem of increasing the competitiveness of technology today is largely determined by the quality of manufacturing large-sized cast billets for their supporting systems. Many factors are involved in forming the service properties of a casting. Each factor is important and affects the quality of the resulting casting. The presence of "cold" slag does not allow refining processes to be fully realized during the induction melting of steel. Therefore, attempts to achieve the same results for induction melting steel without additional furnace treatment as for electric arc melting steel do not always lead to success. In recent years, various methods of out-of-furnace steel processing have been developed, which make it possible to eliminate certain disadvantages of induction melting. One of them is the modification of steel in the bucket with rare earth metals (REM). Additional modification of steel in the ladle along with REM also allows for further improvement of steel quality. Currently, REM, with a high affinity for oxygen, sulfur, nitrogen, non-ferrous metals, and other impurities, are widely used in the steel production. Studies have been carried out to improve the technology of out-of-furnace steel processing and its mechanical properties. The effect of alkaline earth and rare earth master alloys on impact strength and the contamination index with non-metallic inclusions of cold-resistant steel is shown.
Obtaining higher manganese silicide films with high thermoelectric properties
Authors: Bekpulatov I.R. , Shomukhammedova D.S. , Shukurova D.M. , Ibragimova B.V.
Published: January 2023

This article provides information about the process of obtaining a Mn4Si7 film by magnetron sputtering, its high thermoelectric properties, and the possibility of using the resulting film in instrument-making production. Using the magnetron sputtering method, a thin Mn4Si7 film was obtained, and the composition and structure were studied by a scanning electron microscope. Two-stage cleaning of the silicon surface was used in work. Resistivity was determined by the four-probe method, thermoelectric properties, by the two-probe method. The bandwidth of the Mn4Si7/SiO2 film was measured on a high-precision spectrometer according to the law of light reflection. It is shown that the thermoelectric power of the Mn4Si7 film increases during the transition from the amorphous state to the nanocrystalline one, which is associated with the selective scattering of charge carriers at the boundaries of nanoclusters and Mn4Si7 on SiO2/Si have high speed and high sensitivity. It is shown that this film can be used in thermal detectors radiation waves in the visible and IR ranges.
Giardia duodenalis in Hu sheep: occurrence and environmental contamination on large-scale housing farms
Authors: Zhao Qianming , Lu Chenyang , Pei Zhiyang , Gong Pihong , Li Junqiang , Jian Fuchun , Jing Bo , Qi Meng , Ning Changshen
Published: January 2023

Giardia duodenalis is a common zoonotic intestinal parasitic protozoan and sheep are among its hosts; however, limited information is available on sheep kept in large-scale housing. The Hu sheep is a first-class protected local livestock breed in China. In this study, we investigated the seasonal dynamics of G. duodenalis infection in Hu sheep and the environmental contamination of large-scale sheep farms. We collected 474 fecal samples and 312 environmental samples from Hu sheep on a large-scale sheep farm in Henan, China. The prevalence of G. duodenalis was determined by nested PCR targeting the β‑giardin (bg) gene. The assemblages and multilocus genotypes (MLGs) were investigated based on analyses of three genetic loci, i.e. bg, glutamate dehydrogenase (gdh), and triosephosphate isomerase (tpi). To detect mixed infections of different assemblages, assemblage A/E-specific PCRs were performed to amplify the tpi gene. The prevalence of G. duodenalis infection in sheep was 17.9% (81/474) and the positivity rate in environmental samples was 0.96% (3/312). Genetic analysis revealed the presence of two assemblages (assemblages A and E), with assemblage E being detected in both fecal and environmental samples, and assemblage A detected only in fecal samples. A total of 23 MLGs were obtained in fecal and environmental samples, all of which belonged to assemblage E. These results indicate the seasonal dynamics of G. duodenalis infection in sheep and environmental contamination on large-scale housing sheep farms and provide an important reference for the prevention and control of G. duodenalis on large-scale housing sheep farms.
Sessile serrated lesion detection rates continue to increase: 2008–2020
Authors: Edwardson Nicholas , Adsul Prajakta , Gonzalez Zorisadday , Pankratz V. Shane , Parasher Gulshan , English Kevin , Mishra Shiraz
Published: January 2023

Background and study aims We assessed sessile serrated lesion detection rate (SSLDR) at a large academic medical center from 2008 to 2020 and modeled a local, aspirational target SSLDR. We also assessed SSLDRs among all gastroenterology fellows to better understand the relationship between SSLDRs and total colonoscopies performed.

Patients and methods SSL-positive pathology results were flagged from a dataset composed of all screening colonoscopies for average-risk patients from 2008 to 2020. Unadjusted SSLDRs were calculated for individual endoscopists by year. A mixed effects logistic regression was used to estimate the log odds of SSL detection, with one model estimating division-wide predictors of SSL detection and a second model focused exclusively on colonoscopies performed by fellows. Model-adjusted SSLDRs were estimated for all 13 years and across both categories of all endoscopists and fellows only.

Results Adjusted SSLDRs showed a consistent improvement in SSLDR from a low of 0.37 % (95 % confidence interval [CI]: 0.10–0.63) in 2008 to a high of 7.94 % (95 % CI: 6.34–9.54) in 2020. Among fellows only, the odds of SSL detection were significantly lower during their first year compared to their second year (OR: 0.80, 95 % CI: 0.66–0.98) but not significantly higher in their third year compared to their second year (OR: 1.09, 95 % CI: 0.85–1.4).

Conclusions SSLDR increased steadily and significantly throughout our study period but variance among endoscopists persists. The peak SSLDR from 2020 of 7.94 % should serve as the local aspirational target for this division’s attendings and fellows but should be continuously reevaluated.
Pathophysiologie, Diagnostik und Therapie der Lungenkontusion – Empfehlungen der interdisziplinären Arbeitsgruppe der Sektion NIS der DGU und DGT zur
Thoraxtraumaversorgung
Authors: Störmann Philipp , Krämer Sebastian , Raab Stephan , Kalverkamp Sebastian , Graeff Pascal
Published: January 2023

Lungenkontusionen treten in aller Regel in Kombination mit weiteren Verletzungen auf und sprechen für eine hohe Krafteinwirkung. Vor allem bei polytraumatisierten Patienten werden
Lungenkontusionen in hoher Anzahl nachgewiesen. Diese Verletzungen sind u. a. durch eine zeitliche Dynamik charakterisiert, die in der initialen Diagnostik Schwierigkeiten bereiten kann.
Eine korrekte Einordnung des Verletzungsausmaßes in das Gesamtgeschehen und entsprechende diagnostische und therapeutische Schritte sind für das Erreichen einer Ausheilung essenziell. Das
übergeordnete Ziel aller therapeutischen Maßnahmen ist es, dabei die Lungenfunktion bestmöglich zu erhalten und assoziierte Komplikationen wie die Entwicklung einer Pneumonie oder eines ARDS
(Acute Respiratory Distress Syndrome) zu vermeiden.

Die vorliegende Arbeit der interdisziplinären Arbeitsgruppe „Thoraxtrauma“ der Deutschen Gesellschaft für Unfallchirurgie (DGU) und der Deutschen Gesellschaft für Thoraxchirurgie (DGT)
basiert auf einer umfangreichen Literaturrecherche zu Grundlagen, Diagnostik und Behandlung der Lungenkontusion. Es konnten ausnahmslos Arbeiten mit niedrigem Evidenzgrad eingeschlossen
werden. Die Empfehlungen der vorliegenden Arbeit entsprechen einem Konsens der interdisziplinären Arbeitsgruppe.

Zur initialen Diagnostik ist eine CT des Thorax mit Kontrastmittel empfohlen, das Ausmaß der Lungenkontusion korreliert mit dem Auftreten von Komplikationen. Eine konventionelle Aufnahme
des Thorax kann initial die Verletzung unterbewerten, ist aber zur kurzfristigen Verlaufskontrolle geeignet.

Die Therapie der Lungenkontusion ist multimodal und symptomorientiert. Insbesondere die intensivmedizinische Betreuung mit einer lungenprotektiven Beatmung und adäquaten Lagerung sind
Eckpfeiler der Behandlung. Soweit es die Nebenerkrankungen und der Zustand des Patienten zulassen, sollte eine nicht invasive Beatmung erwogen werden. Abhängig von der Lungenbeteiligung und
dem Patientenzustand kann ferner eine ECMO-Therapie als Ultima Ratio erwogen werden. Insbesondere diese sollte nur an spezialisierten Kliniken durchgeführt werden, weswegen eine frühzeitige
Patientenzuweisung oder eine frühe Verlegung im Rahmen von Netzwerkstrukturen antizipiert werden sollte.
COVID-19 Impact on Operative Management of Pediatric Neck Abscesses
Authors: Fadel Mark A. , McCoy Jennifer L. , Obuekwe Fendi , Kitsko Dennis
Published: January 2023

Introduction For multiple reasons, elective pediatric otolaryngology surgical procedures have declined during the COVID-19 pandemic.

Objective The purpose of the present study was to assess whether the prevalence of pediatric neck abscesses managed with operative drainage decreased compared with previous years.

Methods Medical records of all pediatric cases at a tertiary care children's hospital diagnosed with abscess of the neck and treated with incision and drainage were evaluated between the dates of April 1 and November 30 from 2015 to 2020. Outcomes were compared for each year from 2015 to 2019 to 2020, which included location, abscess size, duration of antibiotic treatment, microbiology, and the number of cases per year.

Results A total of 201 cases were included. The mean ± standard deviation (SD) presenting age in the 2015 to 2019 group was 5.05 ± 5.03 years old and 2.24 ± 1.91 years old in the 2020 group. The mean number of cases between 2015 and 2019 was 35.6 ± 4.2, whereas the number of cases in 2020 was 23 (p = 0.002). Of those patients who underwent IV antibiotic therapy prior to presentation (n = 43), the mean number of days before admission was 1.98 ± 2.95 (n = 40) from 2015 to 2019 and 12.00 ± 10.39 (n = 3) in 2020 (p = 0.008). The percent of cases with multiple strains cultured between 2015 and 2019 was 13.4% versus 18.2% in 2020 (p = 0.007).

Conclusion There was a decrease in the number of operative neck abscesses in 2020 compared with the mean number per year from 2015 to 2019. COVID-19 mitigation strategies leading to reduced transmission of other viral and bacterial illnesses and a tendency toward prolonged medical management to avoid surgery are two possible explanations.
Explainable dimensionality reduction (XDR) to unbox AI ‘black box’ models: A study of AI perspectives on the ethnic styles of village dwellings
Authors: Li Xun , Chen Dongsheng , Xu Weipan , Chen Haohui , Li Junjun , Mo Fan
Published: January 2023

Artificial intelligence (AI) has become frequently used in data and knowledge production in diverse domain studies. Scholars began to reflect on the plausibility of AI models that learn unexplained tacit knowledge, spawning the emerging research field, eXplainable AI (XAI). However, superior XAI approaches have yet to emerge that can explain the tacit knowledge acquired by AI models into human-understandable explicit knowledge. This paper proposes a novel eXplainable Dimensionality Reduction (XDR) framework, which aims to effectively translate the high-dimensional tacit knowledge learned by AI into explicit knowledge that is understandable to domain experts. We present a case study of recognizing the ethnic styles of village dwellings in Guangdong, China, via an AI model that can recognize the building footprints from satellite imagery. We find that the patio, size, length, direction and asymmetric shape of the village dwellings are the key to distinguish Canton, Hakka, Teochew or their mixed styles. The data-derived results, including key features, proximity relationships and geographical distribution of the styles are consistent with the findings of existing field studies. Moreover, an evidence of Hakka migration was also found in our results, complementing existing knowledge in architectural and historical geography. This proposed XDR framework can assist experts in diverse fields to further expand their domain knowledge.
Generating plasma using a strong magnetic field directly from solid metal
Authors: McConnon Aili
Published: January 2023

Efficient, low-temperature generation of plasma for semiconductor manufacturing, welding and other applications
Mapping resonance dynamics in water balloons
Authors: Thompson Avery
Published: January 2023

Resonant modes of water balloons mimic simpler dynamics in water drops.
Reducing wake flow with paper-cutting control surfaces
Authors: Thompson Avery
Published: January 2023

The art of paper cutting, kirigami, provides dynamic, programmable control surfaces for changing flow conditions.
Global well-posedness of perturbed Navier–Stokes system around Landau solutions
Authors: Zhang Jingjing , Zhang Ting
Published: January 2023

In this paper, we consider the perturbed Navier–Stokes equations around the Landau solution and investigate the global well-posedness results of the perturbed system with the small initial data in the X−1 space, where X−1=f∈D′R3:∫R3|ξ|−1|f̂|dξ<∞.
Epitaxial growth of a β-Ga2O3 (−201)-oriented thin film on a threefold symmetrical SrTiO3 (111) substrate for heterogeneous integration
Authors: Lu Chao , Gao Lei , Meng Fanqi , Zhang Qinghua , Yang Lihong , Liu Zeng , Zhu Mingtong , Chen Xiaokun , Lyu Xiangyu , Wang Yuqian , Liu Jin , Ji Ailing , Li Peigang , Gu Lin , Cao Zexian , Lu Nianpeng
Published: January 2023

Epitaxial growth of a wide bandgap semiconductor β-Ga2O3 thin film with high crystal quality plays a decisive role in constructing optical and electronic devices. However, except for the native substrate, the scarcity of appropriate non-native substrates or the poor crystallization of the deposit in thin film growth severely limits the fabrication and applicability of the final heterostructures and devices. Here, by taking the consistent symmetry and closely matched atomic spacing between β-Ga2O3 (−201) and the cubic perovskite (111)-oriented plane of SrTiO3, we realize the epitaxial growth of single crystal β-Ga2O3 (−201) thin films on the SrTiO3 (111) substrate by the pulsed laser deposition method, as confirmed by wide-range reciprocal-space mapping and high-resolution scanning transmission electron microscopy. The fabricated β-Ga2O3 (−201) photodetector device on the SrTiO3 (111) substrate exhibits excellent ultraviolet optical detection performance with large on/off switching ratios and a fast response speed. Moreover, the β-Ga2O3/SrTiO3 (111) heterojunction shows type-II heterostructure characteristics for energy band alignment, which displays superior ability for electron–hole pairs separation with large conduction and small valance band offsets of 1.68 and 0.09 eV, respectively. The results offer us a new way to obtain high-quality β-Ga2O3 (−201) thin film heterostructures on cubic SrTiO3 (111) substrates and fabricate β-Ga2O3-based optical and electronic devices.
Spectrum-tailored random fiber laser towards ICF laser facility
Authors: Fan Mengqiu , Lin Shengtao , Yao Ke , Qi Yifei , Zhang Jiaojiao , Zheng Junwen , Wang Pan , Ni Longqun , Bao Xingyu , Zhou Dandan , Zhang Bo , Xiao Kaibo , Xia Handing , Zhang Rui , Li Ping , Zheng Wanguo , Wang Zinan
Published: January 2023

Broadband low-coherence light is considered to be an effective way to suppress laser plasma instability. Recent studies have demonstrated the ability of low-coherence laser facilities to reduce back-scattering during beam–target coupling. However, to ensure simultaneous low coherence and high energy, complex spectral modulation methods and amplification routes have to be adopted. In this work, we propose the use of a random fiber laser (RFL) as the seed source. The spectral features of this RFL can be carefully tailored to provide a good match with the gain characteristics of the laser amplification medium, thus enabling efficient amplification while maintaining low coherence. First, a theoretical model is constructed to give a comprehensive description of the output characteristics of the spectrum-tailored RFL, after which the designed RFL is experimentally realized as a seed source. Through precise pulse shaping and efficient regenerative amplification, a shaped random laser pulse output of 28 mJ is obtained, which is the first random laser system with megawatt-class peak power that is able to achieve low coherence and efficient spectrum-conformal regenerative amplification.
Electron–phonon effects and temperature-dependence of the electronic structure of monoclinic β-Ga2O3
Authors: Lee Channyung , Rock Nathan D. , Islam Ariful , Scarpulla Michael A. , Ertekin Elif
Published: January 2023

Gallium oxide (Ga2O3) is a promising semiconductor for next-generation high-power electronics due to its ultra-wide bandgap and high critical breakdown field. To utilize its unique electrical properties for real-world applications, an accurate description of its electronic structure under device-operating conditions is required. Although the majority of first-principles models focus on the ground state, temperature effects govern the key properties of all semiconductors, including carrier mobility, band edge positions, and optical absorption in indirect gap materials. We report on the temperature-dependent electronic band structure of β-Ga2O3 in a wide temperature range from T = 0 to 900 K using first-principles simulations and optical measurements. Band edge shifts from lattice thermal expansion and phonon-induced lattice vibrations known as electron–phonon renormalization are evaluated by utilizing the quasi-harmonic approximation and the recently developed “one-shot” frozen phonon method, respectively. Electron–phonon effects and thermal expansion together induce a substantial temperature-dependence on the bandgap, reducing it by more than 0.5 eV between T = 0 and 900 K, larger than that observed in other wide bandgap materials. Key implications, including an increase in carrier concentrations, a reduction in carrier mobilities due to localization of band edge states, and an ∼20% reduction in the critical breakdown field, are discussed. Our prediction of temperature-dependent bandgap matches very well with experimental measurements and highlights the importance of accounting for such effects in first-principles simulations of wide bandgap semiconductors.
Steady three-dimensional unbounded flow past an obstacle continuously deviating from a sphere to a cube
Authors: Jbara Layal , Ghigo Arthur , Wachs Anthony
Published: January 2023

We perform three-dimensional particle resolved direct numerical simulations of the flow past a non-spherical obstacle by a Finite Volume cut-cell method, a sub-class of non-body-conforming methods that provides a sharp description of the boundary, which is strictly mass and momentum conservative and can be easily extended to adaptive grids. The present research work discusses the effect of corner rounding and the incidence angle for a range of Reynolds numbers for which the flow exhibits a steady-state behavior. The obstacle is placed in a large cubic domain that properly models an unbounded domain. Hierarchically refined Cartesian meshes are used where the obstacle resides at the finest level of the mesh hierarchy, thus ensuring that the resolution of the boundary layer and the wake of the obstacle is highly accurate, along with significantly reducing the number of grid cells and the computing time. Specifically, we characterize the drag force and the main features of the flow past a bluff obstacle transitioning in shape from spherical to cuboidal through a superquadric geometrical representation. A superquadric representation is suitable for our study since it preserves geometric isometry, and our analysis, thus, focusses on non-sphericity caused by the level of curvature. We investigate a range of Re from 10 to 150, which spans the flow from attached to symmetric and separated past five different obstacle shapes, with the corner radius of the curvature of r/a=2/ζi=1,2/2.5,2/4,2/8 and 0 placed at incidence angles of α=0°, 15°, 30°, and 45° with respect to the streamwise direction. In general, our results show that the obstacle bluffness increases with α and ζi and this increase is more prominent at higher Re. Higher drag forces are a consequence of either higher viscous forces for more streamlined bodies and in less inertial regimes or higher pressure forces for more bluff bodies and in highly inertial regimes, depending on how the corners are contributing to the frontal and lateral surface areas.
Simulation framework for microwave SQUID multiplexer optimization
Authors: Schuster C. , Wegner M. , Kempf S.
Published: January 2023

So far, performance prediction and optimization of microwave SQUID multiplexers have largely been based on simple approximate analytical models and experimental results. This is caused by the complexity of the underlying physics and the intricacy of operation and readout parameters. As a simplified description can never account for all potential effects occurring in a real device, we have developed a software framework to simulate the characteristics and performance of a microwave SQUID multiplexer. Our simulation framework is a powerful tool to guide understanding and optimization of microwave SQUID multiplexers and other related devices. It includes common readout schemes such as open-loop or flux ramp-modulated readout as well as the nonlinear behavior of Josephson tunnel junctions. Moreover, it accounts for the non-zero response time of superconducting microwave resonators with high loaded quality factors as well as the most significant noise contributions such as amplifier noise, resonator noise, as well as SQUID noise. This ultimately leads to a prediction of device performance that is significantly better compared to simple analytical methods. Using the simulation framework, we discuss first steps toward full microwave SQUID multiplexer optimization and highlight some other applications for which our simulation framework can be used.
Universal conductance fluctuations in nanoscale topological insulator devices
Authors: Rashidi Arman , Kealhofer Robert , Lygo Alexander C. , Stemmer Susanne
Published: January 2023

Topological materials are promising candidates in fault-tolerant quantum information processing architectures, making it essential to understand the dephasing mechanisms in these materials. Here, we investigate gated, nanoscale mesas fabricated on thin films of cadmium arsenide (Cd3As2), a three-dimensional Dirac semimetal that can be tuned into different topological phases. We observe two independent types of conductance oscillations, one as a function of the applied magnetic field and the other as a function of the gate voltage. Varying the dimensions of the nanostructures allows the discrimination of a variety of scenarios for similar oscillations previously reported in the literature. We conclude that the conductance oscillations are not a signature of topological boundary states per se, but rather are universal conductance fluctuations. These results broadly inform future interpretations of electronic quantum interference in mesoscopic devices made from topological materials.
A unified method of data assimilation and turbulence modeling for separated flows at high Reynolds numbers
Authors: Wang Zhiyuan , Zhang Weiwei
Published: January 2023

In recent years, machine learning methods represented by deep neural networks (DNNs) have been a new paradigm of turbulence modeling. However, in the scenario of high Reynolds numbers, there are still some bottlenecks, including the lack of high-fidelity data and the stability problem in the coupling process of turbulence models and the Reynolds-averaged Navier–Stokes (RANS) solvers. In this paper, we propose an improved ensemble Kalman inversion method as a unified approach of data assimilation and turbulence modeling for separated flows at high Reynolds numbers. A novel ensemble design method based on transfer learning and a regularizing strategy are proposed to improve the method. The trainable parameters of DNN are optimized according to the given experimental surface pressure coefficients in the framework of mutual coupling between the RANS solvers and DNN eddy viscosity models. In this way, data assimilation and model training are integrated into one step to get the high-fidelity turbulence models agree well with experiments directly. The effectiveness of the method is verified by cases of flows around S809 airfoil at high Reynolds numbers. Through assimilation of few experimental states, we can get turbulence models generalizing well to both attached and separated flows at different angles of attack, which also perform well in stability and robustness. The errors of lift coefficients at high angles of attack are significantly reduced by more than three times compared with the traditional Spalart–Allmaras model.
Numerical investigation of airborne transmission in low-ceiling rooms under displacement ventilation
Authors: Wang Changchang , Hong Jiarong
Published: January 2023

This study employs computational fluid dynamics (CFD) simulations to evaluate the risk of airborne transmission of COVID-19 in low-ceiling rooms, such as elevator cabins, under mechanical displacement ventilation. The simulations take into account the effects of the human body’s thermal environment and respiratory jet dynamics on the transmission of pathogens. The results of the study are used to propose a potential mitigation strategy based on ventilation thermal control to reduce the risk of airborne transmission in these types of enclosed indoor spaces. Our findings demonstrate that as the ventilation rate (Qv) increases, the efficiency of removing airborne particles (εp) initially increases rapidly, reaches a plateau (εp,c) at a critical ventilation rate (Qc), and subsequently increases at a slower rate beyond Qc. The Qc for low-ceiling rooms is lower compared to high-ceiling rooms due to the increased interaction between the thermal plume generated by the occupants or infectors and the ventilation. Further analysis of the flow and temperature fields reveals that εp is closely linked to the thermal stratification fields, as characterized by the thermal interface height and temperature gradient. When Qv < Qc, hT,20.7 < him (him is the height of infector’s mouth) and aerosol particles are injected into the upper warm layer. As Qv increases, the hti also increases following the 3/5 law, which helps displace the particles out of the room, resulting in a rapid increase of εp. However, when Qv > Qc, hT,20.7 > him and aerosol particles are injected into the lower cool layer. The hti deviates from 3/5 law and increases at a much slower rate, causing an aerosol particle lockup effect and the εp to plateau. In addition, as the Qc increases, the local flow recirculation above the infector head is also enhanced, which leads to the trapping of more particles in that area, contributing to the slower increase in εp. The simulations also indicate that the location of infector relative to ventilation inlet/outlet affects Qc and εp,c with higher Qc and lower εp,c observed when infector is in a corner due to potential formation of a local hot spot of high infection risk when infector is near the ventilation inlet. In conclusion, based on the simulations, we propose a potential ventilation thermal control strategy, by adjusting the ventilation temperature, to reduce the risk of airborne transmission in low-ceiling rooms. Our findings indicate that the thermal environment plays a critical role in the transmission of airborne diseases in confined spaces.
Dynamics of chemical reactions on single nanocatalysts with heterogeneous active sites
Authors: Chaudhury Srabanti , Jangid Pankaj , Kolomeisky Anatoly B.
Published: January 2023

Modern chemical science and industries critically depend on the application of various catalytic methods. However, the underlying molecular mechanisms of these processes still remain not fully understood. Recent experimental advances that produced highly-efficient nanoparticle catalysts allowed researchers to obtain more quantitative descriptions, opening the way to clarify the microscopic picture of catalysis. Stimulated by these developments, we present a minimal theoretical model that investigates the effect of heterogeneity in catalytic processes at the single-particle level. Using a discrete-state stochastic framework that accounts for the most relevant chemical transitions, we explicitly evaluated the dynamics of chemical reactions on single heterogeneous nanocatalysts with different types of active sites. It is found that the degree of stochastic noise in nanoparticle catalytic systems depends on several factors that include the heterogeneity of catalytic efficiencies of active sites and distinctions between chemical mechanisms on different active sites. The proposed theoretical approach provides a single-molecule view of heterogeneous catalysis and also suggests possible quantitative routes to clarify some important molecular details of nanocatalysts.