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on the analytical solution of transient friction in channel flows

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Applied Mathematics and Mechanics(English Edition) 2024年第8期45卷 1447-1466页

作者： F.j.GARCíA-GARCíA P.FARINAS-ALVARINo Department of Naval&Industrial Engineering Polytechnic School of EngineeringUniversity of A CorunaCampus Industrial de FerrolFerrol 15403A CorunaSpain Integraciones Técnicas de Seguridad S.A.Pol.Ind.Espiritu SantoC/Nobel15Cambre 15650A CorunaSpain

The transient friction in channel mean flows is the sum of two contributions,i.e.,the underlying laminar flow(ULF)and the purely turbulent component(PTC),and the contributions are analyzed separately by theoretical *** is found that,the transient friction may be higher or remarkably lower than that in equal-Reynolds number steady-state *** universal time constant for plane-parallel laminar flows is reported,and the role of the time constant in a turbulent mean flow is *** is shown that the time constant is related to the turbulence's frozen ***,a study of the logarithmic layer during the transient flow is accomplished,which shows that the logarithmic layer is destroyed.

关键词： transient friction transient flow unsteady channel flow

Energy and blast performance of beryllium in a model thermobaric composition in comparison with aluminum and magnesium

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Defence Technology（防务技术） 2024年第6期36卷 13-19页

作者： Thomas M.Klapotke Stanisław Cudziło Waldemar A.Trzcinski jozef Paszula Energetic Materials Research Department of ChemistryUniversity of Munich(LMU)Butenandtstrasse 5-13(D)81377MunichGermany Military University of Technology Faculty of Advanced Technologies and ChemistrySylwester Kaliski Str.200-908WarsawPoland

A direct comparison is made between the effectiveness of Al,Mg,and Be powders as additional fuels in model thermobaric compositions containing 20%fuel,20%ammonium perchlorate,and 60%RDX(1,3,5-Trinitro-1,3,5-triazacyclohexane)passivated with *** determined calorimetric measurements of the heat of detonation,along with the overpressure histories in an explosion chamber filled with nitrogen,were used to determine the quasi-static pressure(QSP)under anaerobic *** measurements were also performed in a semi-closed bunker,and all blast wave parameters generated after the detonation of 500 g charges of the tested explosives were *** calorimetry results,QSP values,and blast wave parameters(pressure amplitude,specific and total impulses)clearly indicate that Be is much more effective as an additional fuel than either Al or Mg in both anaerobic post-detonation reactions as well as the subsequent aerobic *** heat of detonation of the RDXwax/AP/Be explosive mixture is over 40%and 50%higher than that of the mixture containing aluminum and magnesium instead of beryllium,***,the TNT equivalent of the Be-containing composition due to the overpressure in the nitrogen-filled explosion chamber is 1.66,while the equivalent calculated using an air shock wave-specific impulse at a distance of 2.5 m is equal to *** high values of these parameters confirm the high reactivity of beryllium in both the anaerobic and aerobic stages of the thermobaric explosion.

关键词： Thermobaric explosives Beryllium Heat of detonation Quasi-static overpressure Blast wave parameters

Nutritional epigenetics education improves diet and attitude of parents of children with autism or attention deficit/hyperactivity disorder

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World journal of Psychiatry 2024年第1期14卷 159-178页

作者： Renee j Dufault Katherine M Adler David o Carpenter Steven G Gilbert Raquel A Crider College of Graduate Health Studies A.T.Still UniversityKirksvilleMO 63501United States Department of Research Food Ingredient and Health Research InstituteNaalehuHI 96772United States Department of Health Sciences University of New HavenWest HavenCT 06516United States Institute for Health and the Environment School of Public HealthState University of New YorkAlbanyNY 12222United States Department of Research Institute of Neurotoxicology and Neurological DisordersSeattleWA 98105United States Department of Statistics Food Ingredient and Health Research InstituteNaalehuHI 96772United States

BACKGRoUND Unhealthy maternal diet leads to heavy metal exposures from the consumption of ultra-processed foods that may impact gene behavior across generations,creating conditions for the neurodevelopmental disorders known as autism and attention deficit/hyperactivity disorder(ADHD).Children with these disorders have difficulty metabolizing and excreting heavy metals from their bloodstream,and the severity of their symptoms correlates with the heavy metal levels measured in their *** may play a key role in helping parents reduce their ultra-processed food and dietary heavy metal intake by providing access to effective nutritional epigenetics *** To test the efficacy of nutritional epigenetics instruction in reducing parental ultra-processed food *** The study utilized a semi-randomized test and control group pretest-posttest pilot study design with participants recruited from parents having a learning-disabled child with autism or ***-two parents who met the inclusion criteria were randomly selected to serve in the test(n=11)or control(n=11)*** test group participated in the six-week online nutritional epigenetics tutorial,while the control group did *** efficacy of the nutritional epigenetics instruction was determined by measuring changes in parent diet and attitude using data derived from an online diet survey administered to the participants during the pre and post intervention *** intake scores were derived for both ultra-processed and whole/organic *** sample t-tests were conducted to determine any differences in mean diet scores within each *** There was a significant difference in the diet scores of the test group between the pre-and post-intervention *** parents in the test group significantly reduced their intake of ultra-processed foods with a preintervention diet score of 70(mean=5.385,SD=2.534)and a post-intervention diet score of 113(mean=8.692,SD=1.750)and the

关键词： Epigenomics Parenteral nutrition Autism Attention deficit/hyperactivity disorder Ultra-processed foods Heavy metals

Phase composition,conductivity,and sensor properties of cerium-doped indium oxide

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Nano Materials Science 2024年第2期6卷 193-200页

作者： M.I.Ikim G.N.Gerasimov V.F.Gromov o.j.Ilegbusi L.I.Trakhtenberg N.N.Semenov Federal Research Center for Chemical Physics of RAS MoscowRussia University of Central Florida OrlandoFLUSA Moscow Institute of Physics and Technology(State University) DolgoprudnyMoscow RegionRussia Lomonosov Moscow State University MoscowRussia

The hydrothermal synthesis of In_(2)o_(3)and Ceo_(2)–In_(2)o_(3)is investigated as well as the properties of sensor layers based on these *** the synthesis of In_(2)o_(3),intermediate products In(oH)_(3)and InooH are formed,which are the precursors of stable cubic(c-In_(2)o_(3))and metastable rhombohedral(rh-In_(2)o_(3))phases,respectively.A transition from c-In_(2)o_(3)to rh-In_(2)o_(3)is observed with the addition of Ceo_(2).The introduction of cerium into rh-In_(2)o_(3)results in a decrease in the sensor response to hydrogen,while it increases in composites based on c-In_(2)o_(3).The data on the sensor activity of the composites correlate with XPS results in which Ceo_(2)causes a decrease in the concentrations of chemisorbed oxygen and oxygen vacancies in rh-In_(2)o_(3).The reverse situation is observed in composites based on c-In_(2)o_(3).Compared to In_(2)o_(3)and Ceo_(2)–In_(2)o_(3)obtained by other methods,the synthesized composites demonstrate maximum response to H_(2)at low temperatures by 70–100℃,and have short response time(0.2–0.5 s),short recovery time(6–7 s),and long-term stability.A model is proposed for the dependence of sensitivity on the direction of electron transfer between In_(2)o_(3)and Ceo_(2).

关键词： Cerium oxide Indium oxide Nanocomposite Hydrothermal method Cubic phase Rhombohedral phase Sensor response Conductivity Hydrogen Response/recovery time

Low-Cost and Biodegradable Thermoelectric Devices Based on van der Waals Semiconductors on Paper Substrates

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Energy & Environmental Materials 2024年第1期7卷 201-206页

作者： Gulsum Ersu Carmen Munuera Federico j.Mompean Daniel Vaquero jorge Quereda joão Elias F.S.Rodrigues jose A.Alonso Eduardo Flores jose R.Ares Isabel j.Ferrer Abdullah M.Al-Enizi Ayman Nafady Sruthi Kuriakose joshua o.Island Andres Castellanos-Gomez Materials Science Factory Instituto de Ciencia de Materiales de Madrid(ICMM-CSIC)Madrid E-28049Spain Nanotechnology Group USAL-NanolabUnivesidad de SalamancaSalamanca Junta de Castilla y León 37007Spain GISC Departamento de Física de MaterialesUniversidad Complutense de MadridMadrid E-28040Spain Departamento de Física Aplicada Centro de Investigación y Estudios AvanzadosMérida 97310Mexico MIRE Group Departamento de Física de MaterialesUniversidad Autónoma de MadridMadrid E-28049Spain Instituto Nicolás Cabrera Universidad Autónoma de MadridMadrid E-28049Spain Department of Chemistry College of ScienceKing Saud UniversityRiyadh 11451Saudi Arabia Department of Physics and Astronomy University of Nevada Las VegasLas Vegas NV 89154USA

We present a method to fabricate handcrafted thermoelectric devices on standard office paper *** devices are based on thin films of WS_(2),Te,and BP(P-type semiconductors)and TiS_(3)and TiS_(2)(N-type semiconductors),deposited by simply rubbing powder of these materials against *** thermoelectric properties of these semiconducting films revealed maximum Seebeck coefficients of(+1.32±0.27)mV K^(-1)and(-0.82±0.15)mV K^(-1)for WS_(2)and TiS_(3),***,Peltier elements were fabricated by interconnecting the P-and N-type films with graphite electrodes.A thermopower value up to 6.11 mV K^(-1)was obtained when the Peltier element were constructed with three *** findings of this work show proof-of-concept devices to illustrate the potential application of semiconducting van der Waals materials in future thermoelectric power generation as well as temperature sensing for low-cost disposable electronic devices.

关键词： paper-based electronics Seebeck effect semiconductors thermoelectrics van der Waals materials

Thermochemical co-conversion of biomass-plastic waste to biochar:a review

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Green Chemical Engineering 2024年第1期5卷 31-49页

作者： Adewale George Adeniyi Kingsley o.Iwuozor Ebuka Chizitere Emenike oluwaseun j.Ajala Samuel ogunniyi Kabir B.Muritala Department of Chemical Engineering Faculty of Engineering and TechnologyUniversity of IlorinIlorinP.M.B.1515Nigeria Department of Chemical Engineering Landmark UniversityOmu-AranKwara StateP.M.B.1001Nigeria Department of Pure and Industrial Chemistry Nnamdi Azikiwe UniversityAwkaP.M.B.5025Nigeria Department of Chemistry Federal University of TechnologyBosso CampusMinnaNiger StateP.M.B.65Nigeria

Biomass and plastics are two of the most common municipal solid wastes globally that have continuously placed a burden on the *** is therefore important that they are properly *** coconversion offers a valuable opportunity to recycle biomass and plastics simultaneously into biochar,which reduces the time and cost of recycling them individually while producing a material with a wide range of *** study is a review of published literature that discusses the thermochemical co-processing of biomass and plastic wastes into *** was observed that co-pyrolysis and co-hydrothermal carbonization are the most commonly utilized technologies for this *** characteristics of different biomass and plastics that have been thermochemically converted into biochar were *** properties of the resulting biochar are affected by the feedstock composition,pre-treatment and blending ratio,the reactor’s configuration,reaction temperature,and the presence of a *** studies found that treating the feedstocks separately resulted in a lower yield of biochar than processing them *** biochar created by this procedure has been used as a soil additive and as an adsorbent for water *** perspectives and suggestions,such as the necessity for some technical advancement,biochar’s economic benefits,improved government participation,and raised social awareness,were also *** factors have the potential to propel this field of study to great horizons.

关键词： Biomass Co-pyrolysis Plastic Thermochemical process Valorization

Impact of device resistances in the performance of graphene‑based terahertz photodetectors

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Frontiers of optoelectronics 2024年第2期17卷 87-97页

作者： o.Castelló Sofía M.López Baptista K.Watanabe T.Taniguchi E.Diez j.E.Velázquez-Pérez Y.M.Meziani j.M.Caridad j.A.Delgado-Notario Department of Applied Physics University of Salamanca37008 SalamancaSpain Unidad de Excelencia en Luz y Materia Estructurada(LUMES) University of Salamanca37008 SalamancaSpain Research Center for Electronic and optical Materials National Institute for Materials Science1-1 NamikiTsukuba 305-0044Japan Research Center for Materials Nanoarchitectonics National Institute for Materials Science1-1 NamikiTsukuba 305-0044Japan Nanotechnology Group USAL-NanolabUniversity of Salamanca37008 SalamancaSpain

In recent years,graphene field-effect-transistors(GFETs)have demonstrated an outstanding potential for terahertz(THz)photodetection due to their fast response and *** features are essential to enable emerging THz applications,including 6G wireless communications,quantum information,bioimaging and ***,the overall performance of these photodetectors may be utterly compromised by the impact of internal resistances presented in the device,so-called access or parasitic *** this work,we provide a detailed study of the influence of internal device resistances in the photoresponse of high-mobility dual-gate GFET *** dual-gate architectures allow us to fine tune(decrease)the internal resistance of the device by an order of magnitude and consequently demonstrate an improved responsivity and noise-equivalent-power values of the photodetector,*** results can be well understood by a series resistance model,as shown by the excellent agreement found between the experimental data and theoretical *** findings are therefore relevant to understand and improve the overall performance of existing high-mobility graphene photodetectors.

关键词： Graphene THz Photodetector Field-effect transistor Plasmonic

Characterization of a smog chamber for studying formation of gas-phase products and secondary organic aerosol

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journal of Environmental Sciences 2024年第2期136卷 570-582页

作者： Qi Yuan Zhuozhi Zhang Meng wang Kin Fai Ho Tao wang Shuncheng Lee Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityKowloonHong KongChina School of Public Health and Primary Care The Chinese University of Hong KongShatinHong KongChina

Smog chambers provide a potent approach to explore the secondary organic aerosol formation under varied *** study describes the construction and characterization of a new smog chamber facility for studying the formation mechanisms of gas-phase products and secondary organic aerosol from the photooxidation of volatile organic *** chamber is a 5.4 m^(3) Fluorinated Ethylene Propylene(FEP)Teflon reactor with the potential to perform photooxidation experiments at controlled temperature and relative *** characterizations were conducted for evaluation of stability of environmental parameters,mixing time,background contamination,light intensity,and wall losses of gases and *** photolysis rate of No_(2)(j_(No2))ranged from(1.02-3.32)×10^(-3)sec^(-1),comparable to the average j_(No2)in ambient *** wall loss rates for No,No_(2),and o_(3)were 0.47×10^(-4),0.37×10^(-4),and 1.17×10^(-4)min^(-1),while wall loss of toluene was obsoletely found in a 6 hr *** particle number wall loss rates are(0.01-2.46)×10^(-3)min^(-1)for 40-350 nm with an average lifetime of more than one day.A series of toluene photooxidation experiments were carried out in absence of No_xunder dry *** results of the simulation experiments demonstrated that the chamber is well designed to simulate photolysis progress in the atmosphere.

关键词： Smog chamber Gas-phase oxidation Chamber characterization Chemical mechanism

The CCD instrument background of the SMILE SXI

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Earth and Planetary Physics 2024年第1期8卷 15-24页

作者： M.W.j.Hubbard o.Hetherington D.j.Hall T.W.Buggey S.Parsons T.Arnold A.Holland C.Pagani S.Sembay Centre for Electronic Imaging The Open UniversityMilton KeynesMK76AAUK X-ray and observational Astronomy Group Department of Physics&AstronomyUniversity of LeicesterLE17RHUK

The ESA and CAS SMILE mission orbit is highly elliptical and will pass through multiple radiation *** Soft X-ray Imager(SXI)instrument aboard has a radiation shutter door designed to close when the surrounding radiation flux is *** shutter door will close when passing below an altitude threshold to protect against trapped particles in the Earth’s Van Allen ***,two radiation environments can be approximated based on the shutter door position:open and *** instrument background for the CCDs(Charge-Coupled Devices)that form the focal plane array of the SXI were evaluated for the two *** to the correlation of the space environment with the solar cycle,the solar minima and maxima,the background was also evaluated at these two *** results demonstrated that the highest instrument background will occur during solar minima due to the main contributing source being Galactic Cosmic Rays(GCRs).It was also found that the open background was highest for solar minima and that the closed background was highest during solar *** is due to the radiation shutter door acting as a scattering centre and the changes in the energy flux distribution of the GCRs between the two solar extremes.

关键词： instrument background X-ray astronomy space radiation