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Simulation and experimentation of Propeller-Savonius turbine tested underwater surface

CLEAN ENERGY 2024年第3期8卷 20-33页

作者： Wuryanti, Sri Sasono, Teguh Manunggal, bambang P. Mursanto, Wahyu b. Sugianto Politekn Negeri bandung Politeknik Negeri Bandung Bandung Indonesia Politekn Negeri Padang Dept Mech Engn Padang Indonesia

Indonesia's vast maritime territory offers a unique opportunity for harnessing the potential Energy of seawater currents. This study explores the effectiveness of a combined Savonius and propeller-type turbine system. The Savonius turbine, known for its efficiency in capturing ocean currents due to its large sweep area, is combined with a propeller-type turbine to enhance rotational speed and power generation. A novel approach is employed to induce turbulence and optimize energy extraction, first channeling water through the propeller turbine and then into the Savonius turbine. A comprehensive investigation is conducted through simulations and experimental tests within a controlled tunnel environment. The study explores the performance of two-bladed and three-bladed Propeller-Savonius configurations at varying inlet water velocities (0.1, 0.3, 0.6 and 1.0 m/s). The simulation incorporates a turbulence model with 5% intensity and a hydraulic diameter of 0.216 m. Results indicate that the proposed configuration achieves a maximum power output of 2.0293 W with an impressive efficiency of 63.339% in simulation. Concurrently, experimental testing yields a peak efficiency of 61.335% and turbine power of 0.3951 W. The findings demonstrate the feasibility of the combined turbine system and highlight the importance of turbulence in optimizing energy extraction from seawater currents. This research contributes valuable insights into the design and performance of hybrid turbines for harnessing oceanic Energy, emphasizing the potential for sustainable power generation in maritime regions. The methodology and results presented herein offer a foundation for further exploration and refinement of seawater current energy conversion technologies. The study combines a Savonius turbine and a propeller turbine to enhance rotational speed and power generation. CFD simulations and experiments document performance at different water velocities. The findings show that this system is promisi

关键词： hydro-turbine propeller -Savonius renewable energy water WIND TURbINE PERFORMANCE bLADES CFD RATIO

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Ab initio density response and local field factor of warm dense hydrogen

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Matter and Radiation at Extremes 2024年第5期9卷 48-67页

作者： Tobias Dornheim Sebastian Schwalbe Panagiotis Tolias Maximilian P.böhme Zhandos A.Moldabekov Jan Vorberger Center for Advanced Systems Understanding(CASUS) D-02826 GörlitzGermany Helmholtz-Zentrum Dresden-Rossendorf(HZDR) D-01328 DresdenGermany Space and Plasma Physics Royal Institute of Technology(KTH)Stockholm SE-10044Sweden Technische Universität Dresden D-01062 DresdenGermany

We present quasi-exact ab initio path integral Monte Carlo(PIMC)results for the partial static density responses and local field factors of hydrogen in the warm dense matter regime,from solid density conditions to the strongly compressed *** full dynamic treatment of electrons and protons on the same footing allows us to rigorously quantify both electronic and ionic exchange–correlation effects in the system,and to compare the results with those of earlier incomplete models such as the archetypal uniform electron gas or electrons in a fixed ion snapshot potential that do not take into account the interplay between the two *** full electronic density response is highly sensitive to electronic localization around the ions,and our results constitute unambiguous predictions for upcoming X-ray Thomson scattering experiments with hydrogen jets and fusion *** PIMC results are made freely available and can be used directly for a gamut of applications,including inertial confinement fusion calculations and the modeling of dense astrophysical ***,they constitute invaluable benchmark data for approximate but computationally less demanding approaches such as density functional theory or PIMC within the fixed-node approximation.

关键词： local incomplete rigorous

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Clinical features of gastroesophageal reflux disease and erosive esophagitis:Insights from patients undergoing esophagogastroduodenoscopy in resource-limited Ethiopia

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World Journal of Gastroenterology 2024年第34期30卷 3883-3893页

作者： Firehiwot A Mengistie Abate b Shewaye Abel T Tasamma Zekarias S Ayalew Department of Internal Medicine Addis Ababa UniversityAddis Ababa 1176Addis AbabaEthiopia Department of Internal Medicine Rheum Rheumatology and Internal Medicine Specialty ClinicAddis Ababa 1000Addis AbabaEthiopia Division of Gastroenterology and Hepatology Department of Internal MedicineAdera Medical and Surgical CenterAddis Ababa 1000Addis AbabaEthiopia

bACKGROUND Gastroesophageal reflux disease(GERD)is a common disease worldwide with varying clinical presentations and risk *** data for Africa is lacking,but an increasing trend is expected due to demographic and epidemiological *** endoscopic studies for general gastrointestinal disorders have shown some patients with erosive esophagitis(EE),no studies in Ethiopia have investigated the clinical characteristics,risk factors,and severity of GERD using esophagogastroduodenoscopy(EGD).AIM To assess the clinical features of GERD in Ethiopian patients who underwent EGD and determine the severity and risk factors of *** We conducted a multicenter,retrospective cross-sectional study of 221 patients diagnosed with GERD and endoscopic findings of EE at Trauma Associated Severe Hemorrhage and Amniotic Membrane Stem Cell between January 2019 and August *** were collected from electronic medical records and phone call *** used descriptive statistics and binary logistic regression analysis with SPSS version 26 to identify the association between variables with a statistical significance set at P valueby heartburn(43%).Los Angeles(LA)-A EE was diagnosed in 71.1%of patients,followed by LA-b(14.9%),LA-C(7.7%),and LA-D(5.9%).Multivariate analysis showed that age 50 or above,presence of bleeding,and endoscopic findings of duodenitis/duodenopathy were significantly associated with severe EE(Pbarrett’s esophagus were observed in 4.5%and 1.36%of patients with EE,*** Most of the patients had milder EE with fewer ***,severe EE was more prevalent in older patients and those with duodenitis/duodenopathy.

关键词： Gastroesophageal reflux disease Erosive esophagitis Hiatal hernia Esophagogastroduodenoscopy Heart burn

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Predictive modeling for post operative delirium in elderly

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World Journal of Gastrointestinal Oncology 2024年第9期16卷 3761-3764页

作者： Chris b Lamprecht Abeer Dagra brandon Lucke-Wold Lillian S.Wells Department of Neurosurgery University of FloridaGainevilleFL 32610United States

Delirium,a complex neurocognitive syndrome,frequently emerges following surgery,presenting diverse manifestations and considerable obstacles,especially among the *** editorial delves into the intricate phenomenon of postoperative delirium(POD),shedding light on a study that explores POD in elderly individuals undergoing abdominal malignancy *** study examines pathophysiology and predictive determinants,offering valuable insights into this challenging clinical *** the synthetic minority oversampling technique,a predictive model is developed,incorporating critical risk factors such as comorbidity index,anesthesia grade,and surgical *** is an urgent need for accurate risk factor identification to mitigate POD *** specific to elderly patients with abdominal malignancies,the findings contribute significantly to understanding delirium pathophysiology and *** research is warranted to establish standardized predictive for enhanced generalizability.

关键词： Post-operative delirium Elderly delirium Neurocognitive syndrome Neurotransmitters Abdominal malignancy Predictive model Synthetic minority oversampling technique

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Enumerating Pattern-avoiding Fishburn Permutations Subject to Seven Statistics

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Journal of Mathematical Research with Applications 2024年第4期44卷 427-436页

作者： Yujie DU Philip b.ZHANG College of Mathematical Science Tianjin Normal University

Fishburn permutations are in bijection with several important combinatorial structures including interval orders. In this paper, we use the method of generating trees to enumerate two classes of pattern-avoiding Fishburn permutations subject to 7 classical statistics simultaneously. The classes of our interest are(321,312)-avoiding and(321,4123)-avoiding Fishburn permutations. The statistics of our interest are ascents, descents, inversions, right-to-left maxima, right-to-left minima, left-to-right maxima and left-to-right minima. Our results generalize a result by Egge.

关键词： Fishburn permutation Fishburn number pattern avoidance generating tree

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Progression of e-ticketing implementation for state transportation agencies for asphalt materials

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Journal of Road Engineering 2024年第1期4卷 80-92页

作者： Joshua Withrow Gabriel b.Dadi Hala Nassereddine Department of Civil Engineering University of KentuckyLexingtonKY 40506USA Kentucky Transportation Cabinet FrankfortKY 40622USA

E-ticketing,which has been promoted by the Federal Highway Administration(FHWA)“every day counts”(EDC)initiative,utilizes software applications to digitally track and store information regarding highway construction materials paid by state transportation agencies(STAs)by weight in unit bid contract *** often face implementation barriers such as institutional inertia,or the resistance by stakeholders to adopt changes from the status quo,including new *** purpose of this paper is to determine the progression of STA e-ticketing policy adoption,specifically with a focus on asphalt paving operations,due to the COVID-19 *** accomplish this research effort,previous FHWA data,National Cooperative Highway Research Program(NCHRP)data,and other literatures are reviewed to determine an implementation *** data is collected from the American Association of State Highway and Transportation Officials Committee on Con-struction to gain current feedback from STAs and their highway contractor partners after the COVID-19 ***,a case study featuring the Kentucky Transportation Cabinet(KYTC),the Kentucky Association of Highway Contractors(KAHC),and the Plantmix Asphalt Industry of Kentucky(PAIKY)is performed to provide more in-depth *** major finding includes a statistically significant result indicating increased imple-mentation of e-ticketing for asphalt operations within the last two years,along with noting benefits including employee safety,task loading,and project documentation along with concerns regarding cellular connectivity and procurement *** findings indicate the importance of STAs investing in partnership with con-tractors to improve stakeholder buy-in before proceeding towards e-ticketing adoption.

关键词： Asphalt paving Construction inspection E-ticketing COVID-19

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Measures of Relative and Absolute Convergence and Pro-poor Growth with an Illustration based on China(2010–2018)

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China & World Economy 2024年第2期32卷 1-41页

作者： Elena bárcena-Martin Jacques Silber Yuan Zhang Facultad de Ciencias Económicas y Empresariales Universidad de MálagaSpain Department of Economics Bar-Ilan UniversityIsrael China Center for Economic Studies Fudan UniversityChina

Income mobility is a key issue for understanding the process of economic growth and distributional *** economists have used the concept of“pro-poor growth”to examine,with individual-level panel data,whether the poor benefit more than the rich from economic growth by tracking the extent of income mobility among different population *** is also literature in macroeconomics on the measurement of *** paper introduces population-weighted relative and absolute indices of mobility,convergence,and pro-poor growth;it also distinguishes between anonymous and nonanonymous approaches to these *** empirical analysis is based on Chinese panel data for the period 2010–*** both absolute and relative terms,income growth in China was greater for individuals with an initially lower income but only for lower income deciles in relative *** was also an overall increase in individual welfare from anonymous and nonanonymous perspectives,which was higher among younger *** welfare of the poor did not increase more than that of the *** results shed light on the evolution of income distribution in China during the past decade's rapid economic growth.

关键词： anonymous and nonanonymous approach convergence exchange and structural mobility pro-poor growth

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Excellent photoluminescence and electrochemical properties of Sm^(3+) doped Ca_(2)MgSi_(2)O_(7) nanophosphor:Display and electrochemical sensor applications

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Journal of Rare Earths 2024年第6期42卷 1046-1055,I0002页

作者： R.b.basavaraj K.Sureshkumar D.P.Aarti M.b.Madhusudana Reddy G.Nagaraju T.Ramakrishnappa G.R.Navyashree K.R.Venkatesha babu K.S.Hemalatha Department of Physics BMS Institute of Technology and ManagementBangalore560064India Department of Chemistry BMS Institute of Technology and ManagementBangalore560064India Department of Chemistry School of Applied SciencesREVA UniversityBangalore560064India Energy Materials ResearchLaboratory Department of ChemistrySiddaganga Institute of TechnologyTumakuru57203KarnatakaIndia School of Physical Sciences REVA UniversityBangalore560057Indi Department of Physics Govt.Science CollegeBengaluru560001India Department of Physics Maharani Science College for WomenMaharani Cluster UniversityBengaluru560001India

A series of orange-red light emitting Ca_(2)MgSi_(2)O_(7):Sm^(3+)nanopowders were fabricated via low-cost ecofriendly green combustion technique using Aloe vera gel as *** phase purity of the samples were confirmed by the powder X-ray diffraction(PXRD)*** single-phase tetragonal structure is observed from the PXRD results with no additional impurity *** band gap energy of the fabricated powders was estimated by diffuse reflectance spectra(DRS)and is found to be in the range of 4.01-5.98 eV.A high resolution scanning electron microscope(SEM)was used to study the morphological behaviour of the ***-like structures are observed from the SEM *** particle size was evaluated by transmission electron microscopy(TEM)and is found to be~50 *** interplanar distance is found to be 0.53 *** properties were systematically studied in *** phosphors are successfully excited at 403 nm NUV light,producing reddish-orange characteristic *** emission peaks are centered at 558(^(4)G_(5/2)→^(6)H_(5/2)),607(^(4)G_(5/2)→^(6)H_(7/2))and 645 nm(^(4)G_(5/2)→^(6)H_(9/2)),*** the observed peaks the red emanation(^(4)G_(5/2)→^(6)H_(7/2))is stronger than the orange emission(^(4)G_(5/2)→^(6)H_(5/2))in the current *** photoluminescent concentration quenching is noticed above 5 mol%Sm^(3+)ion doping *** dipole-dipole interaction resulting in cross relaxation is found to be the principal cause of concentration quenching *** color features such as Commission Internationale de I’Eclairage(CIE)and correlated color temperature(CCT)were studied in *** optimized chromaticity coordinates were estimated to be(0.6363,0.3632),which fall in the reddish-orange *** average CCT value obtained is 3362 *** average color purity is found to be~82%.Sm^(3+)incorporated Ca_(2)MgSi_(2)O_(7) samples are possible contender for single white light generation commercial candidates owing to

关键词： Green combustion Photoluminescence Orange-red emission Color purity Sensors Rare earths

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Direct microwave leaching conditions of rare earth elements in fluorescent wastes

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Journal of Rare Earths 2024年第6期42卷 1165-1174,I0007页

作者： A.bilen b.birol M.N.Saridede S.S.Kaplan M.S.Sonmez Department of Metallurgical and Materials Engineering Yildiz Technical UniversityIstanbulTurkey Department of Chemical Engineering and Materials Science Stevens Institute of TechnologyNew JereyUSA Department of Metallurgical and Materials Engineering Istanbul Technical UniversityIstanbulTurkey

The luminescent phosphor powder in the fluorescent lamp constitutes 2%of the lamp’s *** can be mentioned that fluorescent wastes are a crucial raw material to produce rare earth *** the present study,microwave leaching process was conducted to dissolve rare earth elements yttrium(Y),europium(Eu),and remaining rare earth elements(REEs)present in the phosphor powder of the fluorescent *** the yields were *** the microwave leaching process,the effects of the temperature(80-160℃),acid type(hydrochloric acid(HCl),nitric acid(HNO_(3)),sulphuric acid(H_(2)SO_(4))),acid concentration(0.5-6 mol/L),solid to liquid ratio(0.1:10-0.5:10)and reaction time(5-90 min)parameters on leaching efficiencies of varying rare earth elements and calcium were *** highest yield was obtained in the direct microwave leaching of fluorescent waste with the experimental conditions of 6 mol/L HCl,160℃,0.1:10 solid-to-liquid ratio(S:L),and 90 *** energy calculations were made,and kinetic models of the reactions were obtained,and it is observed that Y and Eu dissolution is diffusion-controlled,on the other hand,lanthanum(La),cerium(Ce),and terbium(Tb)were examined to be chemical reaction ***,calcium(Ca)and gadolinium(Gd)seem coherent with the mixed ***,mathematical models of all experimental studies are created with the response surface box-behnken method and the correlation coefficients of all the models are over 90%.

关键词： Rare earth elements(REEs) Direct microwave leaching Fluorescent waste Kinetic models Response surface method

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What diameter?What height?Influence of measures of average tree size on area-based allometric volume relationships

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Forest Ecosystems 2024年第1期11卷 100-109页

作者： Yilin Wang John A.Kershaw Mark J.Ducey Yuan Sun James b.McCarter Integrated Forest Mensuration and Systems Analysis Laboratory Faculty of Forestry and Environmental ManagementUniversity of New BrunswickFrederictonNBCanada Department of Natural Resources and the Environment University of New HampshireDurhamNHUSA College of Forestry Nanjing Forestry UniversityNanjing210037China Scientific Programmer RayonierYuleeFLUSA

Volume is an important attribute used in many forest management *** from 83 fixed-area plots located in central New brunswick,Canada,are used to examine how different measures of stand-level diameter and height influence volume prediction using a stand-level variant of Honer's(1967)volume *** density was included in the models(Volume=f(Diameter,Height,Density))choice of diameter measure was more important than choice of height *** density was not included(Volume=f(Diameter,Height)),the opposite was *** models with density included,moment-based estimators of stand diameter and height performed better than all other *** models without density,largest tree estimators of stand diameter and height performed better than other *** overall best equation used quadratic mean diameter,Lorey's height,and density(root mean square error=5.26 m^3·ha^(-1);1.9%relative error).The best equation without density used mean diameter of the largest trees needed to calculate a stand density index of 400 and the mean height of the tallest 400 trees per ha(root mean square error=32.08 m^(3)·ha^(-1);11.8%relative error).The results of this study have some important implications for height subsampling and LiDAR-derived forest inventory analyses.

关键词： Allometric relationships Stand structure Volume estimation Stand-level attributes

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