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Characterization and modeling of the temperature-dependent thermal conductivity in sintered porous silicon-aluminum nanomaterials

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Nano Research 2022年第6期15卷 5663-5670页

作者： danny Kojda Tommy Hofmann Natalia Gostkowska-Lekner Klaus Habicht Department Dynamics and Transport in Quantum Materials Helmholtz-Zentrum Berlin für Materialien und Energie GmbHBerlin D-14109Germany Institute of Physics and Astronomy University of PotsdamPotsdam D-14476Germany

Nanostructured silicon and silicon-aluminum compounds are synthesized by a novel synthesis strategy based on spark plasma sintering(SPS)of silicon nanopowder,mesoporous silicon(pSi),and aluminum *** interplay of metal-assisted crystallization and inherent porosity is exploited to largely suppress thermal *** and temperaturedependent thermal conductivity studies allow us to elucidate the impact of porosity and nanostructure on the macroscopic heat *** electron microscopy along with quantitative image analysis is applied to characterize the sample morphology in terms of domain size and interpore distance *** demonstrate that nanostructured domains and high porosity can be maintained in densified mesoporous silicon *** contrast,strong grain growth is observed for sintered nanopowders under similar sintering *** observe that aluminum agglomerations induce local grain growth,while aluminum diffusion is observed in porous silicon and dispersed nanoparticles.A detailed analysis of the measured thermal conductivity between 300 and 773 K allows us to distinguish the effect of reduced thermal conductivity caused by porosity from the reduction induced by phonon scattering at nanosized *** a modified Landauer/Lundstrom approach the relative thermal conductivity and the scattering length are *** relative thermal conductivity confirms the applicability of Kirkpatrick’s effective medium *** extracted scattering lengths are in excellent agreement with the harmonic mean of log-normal distributed domain sizes and the interpore distances combined by Matthiessen’s rule.

关键词： thermal conductivity mesoporous silicon porosity spark plasma sintering nanoscale modeling

Book review of Mechanics of Bio-Sediment Transport, Hongwei Fang, Lei Huang, Huiming Zhao, Wei Cheng, Yishan Chen, Mehdi Fazeli, Qianqin Shang (Eds.). Springer-Verlag, Berlin Heidelberg (2020)

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International Journal of Sediment Research 2021年第1期36卷 161-162页

作者： danny D.Reible Donovan Maddox Distinguished Engineering Chair Paul Whitfield Horn ProfessorTexas Tech University

Sediment transport is a classical subject in hydraulic engineering,and relevant to fluvial processes,flood control,reservoir operation,and river *** sediment dynamics studies started in the early 20 th century by scie...

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How I became a statistician — thank you speech at birthday dinner

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Statistical Theory and Related Fields 2018年第2期2卷 222-224页

作者： danny Pfeffermann National Statistician and Director Central Bureau of StatisticsIsraelHebrew University of JerusalemIsraelUniversity of SouthamptonUK

This speech was delivered at the Banquet and Award Ceremony June 17, 2018, during SAE 2018– an international conference on ‘Small Area Estimation and Other Topics of Current Interest inSurveys, Official Statistics, ... 详细信息

关键词： dinner thank speech

Feasibility of achieving net-zero energy performance in high-rise buildings using solar energy

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Energy and Built Environment 2024年第6期5卷 946-956页

作者： Mehrdad Shirinbakhsh L.D.danny Harvey University of Toronto 100St.George StreetTorontoONM5S 3G3Canada

As part of a broad strategy to reach net-zero greenhouse gas emissions and limit global warming,many countries are requiring all new buildings to have net-zero energy *** requires that on-site energy use not exceed on-site generation of renewable energy(taken here to be solar energy),or equivalently,that the building Energy Use Intensity(EUI,kWh/m^(2)a)not exceed the supply of on-site solar energy(electricity and heat)per m^(2)of floor area per *** this basis,we find that achieving net-zero energy performance in an archetype 40-story square building in 16 different cities of North America requires EUI of 17–24 kWh/m^(2)a using PV panels,and 19–28 kWh/m^(2)a using PVT *** building orientation to a non-square floor shape can improve maximum permitted EUI by up to 50%in PV and 60%in PVT ***,the best-performing residential and commercial buildings have EUIs of 50–75 kWh/m^(2)*** if building heights are limited to 5–10 floors does the available solar energy,and thus the permitted EUI,reach 50–75 kWh/m^(2)***,we recommend that policymakers not require high-rise buildings to be net-zero energy,unless they are prepared to limit building heights to 5–10 floors.

关键词： High-rise net-zero energy buildings Building geometry Building height Solar NZEB

Multivariate small area estimation under nonignorable nonresponse

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Statistical Theory and Related Fields 2019年第2期3卷 213-223页

作者： danny Pfeffermann Michael Sverchkov National Statistician and CBS Director JerusalemIsrael Department of Statistics Hebrew UniversityJerusalemIsrael Southampton Statistical Sciences Research Institute(S3RI) University of SouthamptonSouthamptonUK Bureau of Labor Statistics WashingtonDCUSA

We consider multivariate small area estimation under nonignorable, not missing at random(NMAR) nonresponse. We assume a response model that accounts for the different patterns ofthe observed outcomes, (which values are observed and which ones are missing), and estimatethe response probabilities by application of the Missing Information Principle (MIP). By this principle, we first derive the likelihood score equations for the case where the missing outcomes areactually observed, and then integrate out the unobserved outcomes from the score equationswith respect to the distribution holding for the missing data. The latter distribution is definedby the distribution fitted to the observed data for the respondents and the response model. Theintegrated score equations are then solved with respect to the unknown parameters indexingthe response model. Once the response probabilities have been estimated, we impute the missing outcomes from their appropriate distribution, yielding a complete data set with no missingvalues, which is used for predicting the target area means. A parametric bootstrap procedure isdeveloped for assessing the mean squared errors (MSE) of the resulting predictors. We illustratethe approach by a small simulation study.

关键词： Distribution of missing data imputation under nonignorable nonresponse missing information principle MSE estimation NMAR nonresponse

Simulation and animation model to boost mining efficiency and enviro-friendly in multi-pit operations

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International Journal of Mining Science and Technology 2015年第4期25卷 671-674页

作者： Tarshizi Ebrahim Sturgul John Ibarra Virginia Taylor danny Mining & Metallurgical Engineering Department University of Nevada Reno School of Civil Environmental and Mining Engineering University of Adelaide

A discrete-event system simulation and animation program was developed to enhance the efficiency of a truck-excavator operation and reduce the environmental impact of haulage in an open-cut coal mine with multiple-pit operations. In any mine, a key objective is to have sufficient equipment for production and not to have excess to where it becomes counterproductive. Due to the advent of responsible mining,environmental regulations, and eco-friendly practices, these factors must also be considered in the analysis. Simulation studies can be financially advantageous for both the optimization of existing mine operations and new development phases in a mine. This study is a new approach to use discrete-event system simulation for mine systems, in order to investigate and possibly reduce environmental impact considering mining haulage performance and production target. A hypothetical layout of a surface coal mine with two pit operations was used for the simulation and animation model. The simulation model includes the animation of the operation. Animation is helpful to enhance the benefit of a mine simulation model. GPSS/Hòand Proof Professionalòwere the software used for the investigation.

关键词： Simulation and animation Multiple-pit mining Equipment efficiency Truck-excavator allocation Environmental impact WEB-based simulation

The effects of adsorptive materials on microbial community composition and PAH degradation at the sediment capewater interface

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International Journal of Sediment Research 2021年第4期36卷 555-565页

作者： Giovanna Pagnozzi danny D.Reible Kayleigh Millerick Civil Environmental and Construction Engineering Texas Tech University Geosyntec Consultants

Capping with layers of inert or adsorptive materials is used to control the release of polycyclic aromatic hydrocarbons(PAH) in sediment but little is known about microbial degradation processes in these materials. A rich native microbial community inhabits the sediment bed, and capping media can influence enrichment and biodegradation activity of benthic microorganisms. The aim of this study was to evaluate the effects of capping media(sand, organoclay, and powdered activated carbon [PAC]) on microbial communities under oxic conditions typical of the capewater interface, where naphthalene degradation(model PAH) is likely to be maximized. Bench scale experiments compared naphthalene concentrations, nahAc biomarker abundance, microbial community composition, and cellular attachment in systems amended with adsorptive and non-adsorptive capping materials. Results indicate that activated carbon promoted and enhanced bioactivity; PAC treatments showed high biodegradation rates,nahAc biomarker levels, and attached biological growth consistent with enrichment of the PAHdegrading genus Pseudomonae. In contrast, sand did not enhance biological activity compared to media-free systems. Naphthalene strongly influenced microbial community composition at the species level in all treatments except organoclay, which promoted biological signatures commonly associated with impeding degradation activity. Data overall suggest that adsorptive capping materials can both promote(PAC) and inhibit(organoclay) bioactivity in the surficial layer of caps, indicating that media selection is critical to the design of bioactive capping systems.

关键词： Sediments Capping Aerobic biodegradation PAH PAC

Comparison of Loaded Countermovement Jump with Different Variable Resistance Intensities on Inducing Post-Activation Potentiation

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Journal of Science in Sport and Exercise 2020年第2期2卷 167-172页

作者： danny Lum Siow Ee Chen Sport Science and Sport Medicine Singapore Sport InstituteSingaporeSingapore Physical Education and Sports Science National Institute of EducationNanyang Technological UniversitySingaporeSingapore

Purpose The aim of the study was to establish the optimum variable resistance(VR)intensity for loaded countermovement jump(LCMJ)to induce post-activation potentiation(PAP).Methods Eleven male athletes(age 23±2.3 years,height 1.77±0.05 m,body mass 73.7±9.0 kg)attended one familiariza-tion and four testing *** performed their own pre-competition warm up before performing two countermove-ment jumps(CMJ)for baseline ***,they performed 2×3 unloaded(UCMJ)or loaded CMJ(LCMJ)with one of the three VR intensities,Orange(6.7±0.6 kg),Red(14.0±0.9 kg)and Blue(24.0±1.4 kg),in random order,before performing two more CMJ for post-test *** testing session was separated by at least 48 *** There was significant increase in jump height in all conditions(P0.05).There were small to moderate effect when comparing Orange and the other *** force and velocity increased in Red(P<0.05)and Orange(P<0.05),*** in jump height was significantly correlated to change in peak velocity(r=0.46,P=0.002)and peak power(r=0.46,P=0.002).Conclusion The findings of the study showed that UCMJ and LCMJ were effective in improving jump height acutely,and an intensity level of about 10%body weight contributed by VR seems to be the optimum resistance level.

关键词： Resistance band Plyometric Peak power Peak velocity Peak force

Deep learning vs conventional learning algorithms for clinical prediction in Crohn's disease: A proof-of-concept study

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World Journal of Gastroenterology 2021年第38期27卷 6476-6488页

作者： danny Con Daniel R van Langenberg Abhinav Vasudevan Department of Gastroenterology and Hepatology Eastern HealthBox Hill 3128VictoriaAustralia Faculty of Medicine Nursing and Health SciencesMonash UniversityBox Hill 3128VictoriaAustralia

BACKGROUND Traditional methods of developing predictive models in inflammatory bowel diseases(IBD)rely on using statistical regression approaches to deriving clinical scores such as the Crohn's disease(CD)activity ***,traditional approaches are unable to take advantage of more complex data structures such as repeated *** learning methods have the potential ability to automatically find and learn complex,hidden relationships between predictive markers and outcomes,but their application to clinical prediction in CD and IBD has not been explored *** To determine and compare the utility of deep learning with conventional algorithms in predicting response to anti-tumor necrosis factor(anti-TNF)therapy in *** This was a retrospective single-center cohort study of all CD patients who commenced anti-TNF therapy(either adalimumab or infliximab)from January 1,2010 to December 31,*** was defined as a C-reactive protein(CRP)<5 mg/L at 12 mo after anti-TNF *** supervised learning algorithms were compared:(1)A conventional statistical learning algorithm using multivariable logistic regression on baseline data only;(2)A deep learning algorithm using a feed-forward artificial neural network on baseline data only;and(3)A deep learning algorithm using a recurrent neural network on repeated *** performance was assessed using area under the receiver operator characteristic curve(AUC)after 10×repeated 5-fold *** A total of 146 patients were included(median age 36 years,48%male).Concomitant therapy at anti-TNF commencement included thiopurines(68%),methotrexate(18%),corticosteroids(44%)and aminosalicylates(33%).After 12 mo,64%had CRP<5 mg/*** conventional learning algorithm selected the following baseline variables for the predictive model:Complex disease behavior,albumin,monocytes,lymphocytes,mean corpuscular hemoglobin concentration and gamma-glutamyl transferase,and had a cross-valid

关键词： Machine learning Artificial intelligence Precision medicine Personalized medicine Deep learning