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On the Features of Thermal Convection in a Compressible Gas

Fluid Dynamics & Materials Processing 2024年第5期20卷 957-974页

作者： Igor b.Palymskiy Physics Department Siberian State University of Telecommunications and Information SciencesNovosibirsk City630102Russia Physics Department Siberian State University of Geosystems and TechnologiesNovosibirsk City630108Russia

The fully nonlinear equations of gas dynamics are solved in the framework of a numerical approach in order to study the stability of the steady mode of Rayleigh-bénard convection in compressible,viscous and heat-conducting gases encapsulated in containers with no-slip boundaries and isothermal top and bottom *** initial linear temperature profile is assumed.A map of the possible convective modes is presented assuming the height of the region and the value of the temperature gradient as influential *** a relatively small height,isobaric convection is found to take place,which is taken over by an adiabatic mode when the height exceeds the critical value,or by a super-adiabatic mode in case of a relatively high temperature *** the adiabatic mode,convective flow develops due to adiabatic processes given a stable initial *** analytic formula for the critical height of the region is derived taking into account and neglecting the dependence of the gas viscosity on the ***,an analytic formula is obtained for the upper boundary of the region of applicability of the boussinesq approximation for incompressible *** models for compressible gases are relevant to practical situations such as the study of convective flows in spatially extended gas mixtures when dealing with safety issues related to hydrocarbons stored in gas stations.A dangerous situation arises when the tank is almost empty but some hydrocarbon is left at the bottom of the *** the presence of convective flows,the vaporized fuel is mixed with the oxidizer(air)forming a gas-vapor ***,if the volumetric concentration of fuel vapor(hydrocarbon)is in the interval between the lower and upper concentration limits of ignition,then the gas-vapor mixture becomes explosive and any accidental spark is sufficient to cause an emergency.

关键词： Rayleigh-bénard convection gas stable stratification unstable stratification temperature gradient

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Rural Resilience: A Comprehensive Study on Water Supply, Sanitation, Disease Patterns, and Hygiene Practices in Munshiganj, bangladesh

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Journal of Environmental Protection 2024年第1期15卷 63-75页

作者： Jubayer Hoque Rifat Islam Md. Mustafizur rahman Md. Golam Rabbani Md. Selim Reja Saifur rahman Soykat Saim Raiyan Md. Shafiqul Ahsan Emon Sakil Khan Department of Environmental Science and Disaster Management Bangabandhu Sheikh Mujibur Rahman Science and Technology University Gopalgnj Bangladesh Department of Political Science Bangabandhu Sheikh Mujibur Rahman Science and Technology University GopalgnjBangladesh Department of Statistics Bangabandhu Sheikh Mujibur Rahman Science and Technology University Gopalgnj Bangladesh

This research project investigates the current status of water supply, sanitation, and hygiene practices in Munshiganj District, bangladesh. Data collection involved a structured questionnaire and a reconnaissance survey. Findings reveal that 30% of individuals rely on surface water (hand-tube wells, rivers, and ponds), prioritized as canal > river > pond, while 70% depend on groundwater (subterranean electric motor, deep tube-well). Drinking water is generally sufficient, with 95% reporting adequacy throughout the year. About 45% use hand tube-well water, 28% use deep tube-well water, and 11% use supply tap water for various purposes. bathing trends include underground water through electric motor > pond > hand tube-well water > river, while for cooking, the order is underground water through electric motor > pond > hand tube-well water > river. Toilet water supply ranks as supply tap water > hand tube-well water > deep tube-well water. Although sanitation awareness is high, some lack knowledge of good hygiene practices. After defecating, handwashing methods include soap, ash, soil, or water. Children’s waste disposal varies, with some discarding it in open areas. Approximately 40% suffer from diseases like Diarrhoea due to unsafe water, primarily affecting children and elders. Training exists, but a significant portion lacks sanitation education. Dry skin or exposure to cold water may cause temporary irritation. Local government involvement in sanitation efforts is less active compared to non-governmental organizations. Results emphasize the need to enhance community awareness of safe water supplies and sanitation practices. .

关键词： Water Supply Sanitation Practices Hygiene Awareness Groundwater Dependency Community Health Intervention

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Incidence of exclusive extrapelvic skeletal metastasis in prostate carcinoma on bone scintigraphy

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World Journal of Radiology 2024年第7期16卷 265-273页

作者： Parneet Singh Kanhaiyalal Agrawal Ashique rahman Tejasvini Singhal Girish Kumar Parida Gopinath Gnanasegaran Department of Nuclear Medicine All India Institute of Medical SciencesBhubaneshwar 751019OdishaIndia Department of Nuclear Medicine Royal Free HospitalLondon NW32QGUnited Kingdom

bACKGROUND bone is one of the common sites of metastasis from prostate *** scintigraphy(bS)is one of the most sensitive imaging modalities currently used for bone metastatic *** metastasis in prostate carcinoma commonly involves pelvic bones but rarely involves extrapelvic-extraspinal *** To retrospectively analyze the bS data to determine the pattern of skeletal metastases in the prostate *** This retrospective observational study involves patients with biopsy-proven prostate carcinoma referred for bS for staging *** with abnormal bS were evaluated for the pattern of skeletal involvement and data were pre-sented in descriptive format in the form of *** A total of 150 patients with biopsy-proven prostate cancer who were referred for staging were included in the *** of 150 patients(8.67%)had no abnormal uptake on planar images,ruling out metastatic ***-four patients(16%)had heterogeneous uptake in the spine with distribution charac-teristic of degenerative disease and no scan pattern of metastatic *** patients(20%)had multifocal uptake involving both pelvic and extra pelvic bones on planar images typical for skeletal metastasis and were considered ***-three out of 150 patients(55.3%)had increased tracer uptake,which was indeterminate,thus,single photon emission computed tomography-computed tomography(SPECT-CT)was acquired,which showed 51 with metastatic disease,31 benign lesions,and one indeterminate *** of 150 patients had exclusive pelvic bone uptake,which was found to be metastatic in 4/7 patients in *** six out of 150 patients showed exclusive extrapelvic tracer uptake,of which only 3 had vertebral metastatic *** of the patients with increased uptake exclusively in the extrapelvic-extraspinal location was *** The incidence of exclusive extrapelvic skeletal metastatic disease in prostate carcinom

关键词： Pelvic Prostate cancer bone scan Single photon emission computed tomography-computed tomography Skeletal metastasis

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Learning to become addicted,one synapse at a time

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Neural Regeneration Research 2024年第2期19卷 401-402页

作者： Alessio Attardo Sidney b.Cambridge Leibniz Institute for Neurobiology MagdeburgGermany Institute for Anatomy II Dr.Senckenberg AnatomyGoethe-University Frankfurt am MainFrankfurtGermany

Addiction has been extensively studied on many levels:from the molecular level,with various“omics”approaches(Natividad et al.,2018;Grecco et al.,2021),to the clinical level,with psychotherapy and MRI imaging(Ceceli ... 详细信息

关键词： clinical therapy

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Prevalence of Dental Anomalies among Patients Who Report to the Komfo Anokye Teaching Hospital’s Orthodontic Clinic

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Open Journal of Stomatology 2024年第2期14卷 103-117页

作者： Ama Agyeibea Amuasi Daniel K. Sabbah Alexander Oti-Achempong rahman N. Mamah The Department Child Oral Health & Orthodontics School of Medicine and Dentistry College of Health Sciences Kwame Nkrumah University of Science and Technology Kumasi Ghana The Department of Oral & Maxillofacial Sciences School of Medicine and Dentistry College of Health Sciences Kwame Nkrumah University of Science and Technology Kumasi Ghana

bACKGROUND: Dental anomalies are variations from the established well-known general anatomy and morphology of the tooth as a result of disturbances during tooth formation. They can be developmental, congenital, or acquired and may be localized to a single tooth or involve systemic conditions. AIM: To evaluate the prevalence of dental anomalies in patients who report to the Komfo Anokye Teaching Hospital (KATH) dental clinics. METHOD: A descriptive cross-sectional design was used with a sample size of 92 patients aged 18 or older, obtained through convenience sampling. Data analysis was performed using SPSS version 26.0. RESULTS: The study included 92 patients aged 18 to 72 years, with 47.8% males and 52.2% females. Dental anomalies were observed in 51.1% of participants, with a higher prevalence in females (55.3%). The most common anomalies were diastema (48.3%), impacted teeth (22.0%), dilaceration (11.9%), and peg-shaped lateral teeth (6.8%). CONCLUSION: This study highlights the importance of conducting thorough dental examinations to identify and address dental anomalies, which may have implications for treatment. Early detection and correction of these anomalies are crucial to prevent future complications.

关键词： Dental Anomalies Prevalence Impacted Teeth Dilaceration

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Study of hybrid nanofluid flow in a stationary cone-disk system with temperature-dependent fluid properties

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Applied Mathematics and Mechanics(English Edition) 2024年第4期45卷 677-694页

作者： A.S.JOHN b.MAHANTHESH G.LORENZINI Center for Mathematical Needs Department of MathematicsCHRIST(Deemed to be University)Karnataka 560029India School of Mathematical and Statistical Sciences The University of Texas Rio Grande ValleyTexas 78539U.S.A. Department of Engineering and Architecture University of ParmaParma 43124Italy

Cone-disk systems find frequent use such as conical diffusers,medical devices,various rheometric,and viscosimetry *** this study,we investigate the three-dimensional flow of a water-based Ag-Mg O hybrid nanofluid in a static cone-disk system while considering temperature-dependent fluid *** the variable fluid properties affect the dynamics and heat transfer features is studied by Reynolds's linearized model for variable viscosity and Chiam's model for variable thermal *** single-phase nanofluid model is utilized to describe convective heat transfer in hybrid nanofluids,incorporating the experimental *** model is developed as a coupled system of convective-diffusion equations,encompassing the conservation of momentum and the conservation of thermal energy,in conjunction with an incompressibility condition.A self-similar model is developed by the Lie-group scaling transformations,and the subsequent self-similar equations are then solved *** influence of variable fluid parameters on both swirling and non-swirling flow cases is ***,the Nusselt number for the disk surface is *** is found that an increase in the temperature-dependent viscosity parameter enhances heat transfer characteristics in the static cone-disk system,while the thermal conductivity parameter has the opposite effect.

关键词： hybrid nanofluid cone-disk system laminar flow variable fluid property Nusselt number

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Quantum correlations and entanglement in coupled optomechanical resonators with photon hopping via Gaussian interferometric power analysis

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Chinese Physics b 2024年第5期33卷 204-211页

作者： Y.Lahlou b.Maroufi M.Daoud LPHE-MS Department of PhysicsFaculty of SciencesMohammed V UniversityRabatMorocco LPMS Department of PhysicsFaculty of SciencesIbn Tofail UniversityKénitraMorocco

Quantum correlations that surpass entanglement are of great importance in the realms of quantum information processing and quantum ***,for quantum systems prepared in pure states,it is difficult to differentiate between quantum entanglement and quantum ***,this indistinguishability is no longer holds for mixed *** contribute to a better understanding of this differentiation,we have explored a simple model for both generating and measuring these quantum *** study concerns two macroscopic mechanical resonators placed in separate Fabry–Pérot cavities,coupled through the photon hopping *** system offers a comprehensively way to investigate and quantify quantum correlations beyond entanglement between these mechanical *** key ingredient in analyzing quantum correlation in this system is the global covariance *** forms the basis for computing two essential metrics:the logarithmic negativity(E_(N)^(m))and the Gaussian interferometric power(P_(G)^(m)).These metrics provide the tools to measure the degree of quantum entanglement and quantum correlations,*** study reveals that the Gaussian interferometric power(P_(G)^(m))proves to be a more suitable metric for characterizing quantum correlations among the mechanical modes in an optomechanical quantum system,particularly in scenarios featuring resilient photon hopping.

关键词： quantum correlations entanglement Gaussian interferometric power logarithmic negativity optomechanics photon hopping

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Optimal Control of Service Rates of Discrete-Time(s,Q)Queueing-Inventory Systems with Finite buffer

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Journal of Systems Science and Systems Engineering 2024年第3期33卷 261-280页

作者： L.Iniya b.Sivakumar G.Arivarignan School of Mathematics Madurai Kamaraj UniversityMaduraiTamilnaduIndia Department of Statistics Manonmaniam Sundaranar UniversityTirunelveliTamilnaduIndia

This article,we develop an optimal policy to control the service rate of a discrete time queueing-inventory system with finite *** customers arrive according to a bernoulli process and the service time for the customers are *** the buffer size attains its maximum,any arriving new customers are considered to be *** customers are served one by one according to FCFS rule and each customers request random number of *** inventory is replenished according to a(s,Q)inventory policy with geometric lead *** main objectives of this article are to determine the service rates to be employed at each slot so that the long run expected cost rate is minimized for fixed inventory level and fixed buffer size and to minimize the expected waiting time for a fixed inventory level and fixed buffer *** problems are modelled as Markov decision *** establish the existence of a stationary policy and employ linear programming method to find the optimal service *** provide some numerical examples to illustrate the behaviour of the model.

关键词： Queueing-inventory system discrete time batch demand-Markov decision process

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The great catastrophe: causes of the Permo-Triassic marine mass extinction

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National Science Review 2024年第1期11卷 37-50页

作者： Paul b.Wignall David P.G.bond School of Earth & Environment University of Leeds School of Environmental Sciences University of Hull

The marine losses during the Permo-Triassic mass extinction were the worst ever experienced. All groups were badly affected, especially amongst the benthos(e.g. brachiopods, corals, bryozoans, foraminifers,ostracods). Planktonic populations underwent a fundamental change with eukaryotic algae being replaced by nitrogen-fixing bacteria, green-sulphur bacteria, sulphate-reducing bacteria and prasinophytes. Detailed studies of boundary sections, especially those in South China, have resolved the crisis to a ～55 kyr interval straddling the Permo-Triassic boundary. Many of the losses occur at the beginning and end of this interval painting a picture of a two-phase extinction. Improved knowledge of the extinction has been supported by numerous geochemical studies that allow diverse proposed extinction mechanisms to be studied. A transition from oxygenated to anoxic-euxinic conditions is seen in most sections globally, although the intensity and timing shows regional variability. Decreased ocean ventilation coincides with rapidly rising temperatures and many extinction scenarios attribute the losses to both anoxia and high *** kill mechanisms include ocean acidification for which there is conflicting support from geochemical proxies and, even less likely, siltation(burial under a massive influx of terrigenous sediment) which lacks substantive sedimentological evidence. The ultimate driver of the catastrophic changes at the end of the Permian was likely Siberian Trap eruptions and their associated carbon dioxide emissions with consequences such as warming, ocean stagnation and acidification. Volcanic winter episodes stemming from Siberian volcanism have also been linked to the crisis, but the short-term nature of these episodes(boreal latitudes

关键词： ocean anoxia ocean acidification siltation productivity collapse volcanic winter

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Klippel Trenaunay Syndrome with Angiokeratoma Circumscriptum Naeviforme and bilateral Congenital Anorchia: A Rare Association

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Open Journal of Pediatrics 2024年第1期14卷 43-49页

作者： Mujammel Haque Kalyan benjamin Gomes Sajib Kumar Talukdhar Mustafizur rahman Farzana Sharmin Manik Kumar Talukder Department of Paediatrics Bangabandhu Sheikh Mujib Medical University Dhaka Bangladesh

Klippel-Trenaunay syndrome (KTS) is not a common congenital vascular abnormality. A trio of capillary malformation, venous varicosities, and bony or soft-tissue hypertrophy define this syndrome. Significant morbidities associated with this illness include bleeding, deep vein thrombosis, and embolic consequences. Angiokeratoma circumscriptum naeviforme (ACN) is indeed a congenital variant of angiokeratoma that appears as a hyperkeratotic plaque on the lower extremity. bilateral congenital anorchia (bCA) is the total lack of testicular tissue in a male with a normal phenotype and karyotype. KTS has been linked to ACN. Here we presented an 8-year-old male child who came with a swollen left thigh and the right side of his face with overlying blackish nodules on his left thigh and scrotum. The patient was diagnosed as KTS with angiokeratoma circumscriptum naeviforme and bilateral congenital anorchia based on his history, imaging studies and the typical clinical features of the disease.

关键词： Klippel-Trenaunay Syndrome Angiokeratoma Circumscriptum Neviforme bilateral Congenital Anorchia

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