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CLT Fabricated with Gmelina arborea and Tectona grandis Wood from Fast-Growth Forest Plantations: Physical and Mechanical Properties

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Journal of Renewable Materials 2022年第1期10卷 1-17页

作者： Freddy Munoz Carolina Tenorio roger Moya Angel Navarro-Mora Escuela de Ingenieria Forestal Instituto Tecnologico de Costa RicaCartago159-7050Costa Rica Escuela de Ingenieria en Construccion Instituto Tecnologico de Costa RicaCartago159-7050Costa Rica

Fabrication and use of Cross Laminated Timber(CLT)using tropical woods is still limited at *** objective of the present study aims to determine the possibility of using CLT panels of 3 and 5 layers,fabricated withTectona grandis and Gmelina arborea wood using adhesive of isocyanate polymer emulsion system catalyzed with polymeric ***,water absorption,density,flexure test,compression and glue-line shear were evaluated using ANSI/APA PRG320-2012 ASTM D198 and ASTM D4761 *** results showed that CLT panels of *** presented higher values of density,less water absorption and lower delamination,with no evident differences between the CLT of 3 and 5 *** high density of *** resulted in higher values of the mechanical *** flatwise and edgewise flexure tests in 5-layer CLT panels of both species pre-sented higher values of bending stiffness compared to those of 3-layer CLT *** the bending stress values in 3-layer CLT panels were higher than for 5-layer CLT *** for shear stress in bending flatwise,in both species,3-layer CLT surpassed 5-layer CLT panels,but in the edgewise test no differences were *** MOE and Fc in the compression test were superior in relation to the edgewise *** and Fc in compres-sion flatwise in 3-layer CLT was greater than in 5-layer CLT in both species,but edgewise these values were higher in 5-layer CLT *** most common failures were stress and delamination in the flexure test,whereas in the compression test these were:shearing,splitting and *** the glue-line shear test no differences were observed between CLT panels of 3 and 5 layers for both species.

关键词： Structural elements sustainable material building material tropical wood wood of plantation

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叽叽喳喳直播间

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小哥白尼（野生动物） 2024年第7期 34-34页

作者： roger Puillandre(图) 无不详视觉中国

一大拨弹幕正在向你袭来……妈妈,我嘴里养了一条小鱼,快看!(沧州韩宣雅)看,我用嘴巴做了条瀑布,厉害吧?!(微信管子涵)飞流直下三千尺,疑是银河落九天。让我尝尝这瀑布的水甜不甜。(江苏封思琪)大家好,今天是我做吃播主播的第一天。首先... 详细信息

一大拨弹幕正在向你袭来……妈妈,我嘴里养了一条小鱼,快看!(沧州韩宣雅)看,我用嘴巴做了条瀑布,厉害吧?!(微信管子涵)飞流直下三千尺,疑是银河落九天。让我尝尝这瀑布的水甜不甜。(江苏封思琪)大家好,今天是我做吃播主播的第一天。首先,我要吃一个苹果。哎哟,这位观众,你的口水这么快就流出来了!

关键词：微信主播瀑布直播间吃播

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Profile of Full-Term Births in Maternity Wards of Public Hospitals in Douala Cameroon

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Open Journal of Obstetrics and Gynecology 2024年第5期14卷 705-720页

作者： Henri Essome Merlin Boten Bounyom Astrid Ndolo Kondo Ingrid Doriane Ofakem Ilick Fulbert Mangala Nkwele Irène Cyrielle Edjoa Mboe Michel roger Ekono Alphonse Ngalame Nyong Robert Tchounzou Moustapha Bilkissou Junie Ngaha Yaneu Marga Vanina Ngono Akam Gervais Mounchikpou Ngouhouo Grâce Tocki Toutou Théophile Nana Njamen Valère Mve Koh Pascal Foumane Faculty of Medicine and Pharmaceutical Sciences University of Douala Douala Cameroon Laquintinie Hospital Douala Cameroon Faculty of Health Sciences University of Bamenda Bamenda Cameroon Faculty of Health Sciences University of Buea Buea Cameroon Faculty of Medicine and Biomedical Sciences University of Yaound&#233 1 Yaound&#233 Cameroon Faculty of Medicine and Pharmaceutical Sciences of Sangmelima University of Ebolowa Ebolowa Cameroon

Introduction: Pregnancy as much as childbirth constitutes a risky situation, potentially fraught with sometimes dramatic complications: maternal death. Objective: We conducted this study with the aim of establishing the profile of those giving birth in our context with the aim to anticipate operationally in the future on morbidity but more on maternal deaths. Methodology: We conducted, using a structured questionnaire, a prospective descriptive study in representative maternity wards in the city of Douala;the study variables were socio-economic, anthropometric, obstetrical and clinical. Statistical analyses were carried out with CS Pro 7.3 and SPSS version 25.0 software. The Student, Chi-square and Fischer tests were used to compare the means of the variables and the percentages. Results: We recruited 305 births for our study. The average age of our births was 28.7 years ± 6.1 with an average height of 161.6 cm ± 5.06;an average body mass index at the start of pregnancy of 28.0 kilograms/square meter and 31.3 kilograms/square meter at delivery;the average weight gain was 8.4 g ± 5.37;an average gestation of 2.84±1.90;an average parity of 2.2 ± 2.1 with an average birth interval of 27.7 months ± 23.7. The average gestational age was 39.2 weeks ± 1.21 with pregnancy pathology dominated by malaria;85.9% began their prenatal follow-up before the 14th week of amenorrhea. Conclusion: The profile of childbirth in urban Cameroon does not seem potentially dystocic compared to that of the same regional and racial area.

关键词： Profile Delivery Term Malaria Douala

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Air-stable n-type transistors based on assembled aligned carbon nanotube arrays and their application in complementary metal-oxide-semiconductor electronics

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Nano Research 2022年第2期15卷 864-871页

作者： Zhen Li Katherine R.Jinkins Dingzhou Cui Mingrui Chen Zhiyuan Zhao Michael S.arnold Chongwu Zhou Ming Hsieh Department of Electrical Engineering Mork Family Department of Chemical Engineering and Materials Scienceand Department of Physics and AstronomyUniversity of Southern CaliforniaLos AngelesCalifornia 90089USA Department of Materials Science and Engineering University of Wisconsin-MadisonMadisonWisconsin 53706USA

Carbon nanotubes(CNTs)are ideal candidates for beyond-silicon nano-electronics because of their high mobility and low-cost ***,assembled massively aligned CNTs have emerged as an important platform for semiconductor ***,realizing sophisticated complementary nano-electronics has been challenging due to the p-type nature of carbon nanotubes in *** of n-type behavior field effect transistors(FETs)based on assembled aligned CNT arrays is needed for advanced CNT *** in this paper,we report a scalable process to make n-type behavior FETs based on assembled aligned CNT ***-stable and high-performance n-type behavior CNT FETs are achieved with high yield by combining the atomic layer deposition dielectric and metal contact *** also systematically studied the contribution of metal contacts and atomic layer deposition passivation in determining the transistor *** on these experimental results,we report the successful demonstration of complementary metal-oxide-semiconductor inverters with good performance,which paves the way for realizing the promising future of carbon nanotube nano-electronics.

关键词： carbon nanotube field effect transistor air-stable complementary metal-oxide-semiconductor

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Detailed bed topography and sediment load measurements for two stepdown flows in a laboratory flume

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International Journal of Sediment Research 2022年第3期37卷 287-298页

作者： Daniel Wren roger Kuhnle Tate Mc Alpin David Abraham Keaton Jones United States Department of Agriculture Agricultural Research Service National Sedimentation Laboratory U.S.Army Research and Development Center Coastal and Hydraulics Laboratory

Streams and rivers, particularly smaller ones, often do not maintain steady flow rates for long enough to reach equilibrium conditions for sediment transport and bed topography. In particular, streams in small watersheds may be subject to rapidly changing hydrographs, and relict bedforms from previous high flows can cause further disequilibrium that complicates the prediction of sediment transport rates. In order to advance the understanding of how bedforms respond to rapid changes in flow rate, a series of flume experiments were performed where the flow was reduced rapidly from equilibrium *** transport rates and bed elevation data across the flume and over a 15-meter-long test section were collected during the experiments to allow detailed examination of evolving bedform dynamics. It was found that relict bedforms stopped moving completely after flow reductions, and the mode of sediment transport was shifted to small bedforms that arose rapidly over dune stoss sections throughout the test section. The changes in sediment transport with time as the sand bed adjusted to the new flow rate was found to agree with predictions based on the relations proposed in Wren et al.(2020). Wavelet analysis is used to visualize changes in length and amplitude scales during the bed transition process.

关键词： Sediment transport Bedforms Dunes Wavelets

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Curl Constraint-Preserving Reconstruction and the Guidance it Gives for Mimetic Scheme Design

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Communications on Applied Mathematics and Computation 2023年第1期5卷 235-294页

作者： Dinshaw S.Balsara roger Käppeli Walter Boscheri Michael Dumbser Physics and ACMS Departments University of Notre DameNotre DameINUSA Seminar for Applied Mathematics(SAM) Department of MathematicsETH ZürichCH-8092 ZurichSwitzerland Department of Mathematics and Computer Science University of FerraraFerraraItaly Laboratory of Applied Mathematics Department of CivilEnvironmental and Mechanical EngineeringUniversity of TrentoTrentoItaly

Several important PDE systems,like magnetohydrodynamics and computational electrodynamics,are known to support involutions where the divergence of a vector field evolves in divergence-free or divergence constraint-preserving ***,new classes of PDE systems have emerged for hyperelasticity,compressible multiphase flows,so-called firstorder reductions of the Einstein field equations,or a novel first-order hyperbolic reformulation of Schrödinger’s equation,to name a few,where the involution in the PDE supports curl-free or curl constraint-preserving evolution of a vector *** study the problem of curl constraint-preserving reconstruction as it pertains to the design of mimetic finite volume(FV)WENO-like schemes for PDEs that support a curl-preserving involution.(Some insights into discontinuous Galerkin(DG)schemes are also drawn,though that is not the prime focus of this paper.)This is done for two-and three-dimensional structured mesh problems where we deliver closed form expressions for the *** importance of multidimensional Riemann solvers in facilitating the design of such schemes is also *** two dimensions,a von Neumann analysis of structure-preserving WENOlike schemes that mimetically satisfy the curl constraints,is also *** shows the tremendous value of higher order WENO-like schemes in minimizing dissipation and dispersion for this class of *** results are also presented to show that the edge-centered curl-preserving(ECCP)schemes meet their design *** paper is the first paper that invents non-linearly hybridized curl-preserving reconstruction and integrates it with higher order Godunov *** its very design,this paper is,therefore,intended to be forward-looking and to set the stage for future work on curl involution-constrained PDEs.

关键词： PDEs Numerical schemes Mimetic

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Promotion effect of niobium on ceria catalyst for selective catalytic reduction of NO with NH3

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Journal of Rare Earths 2022年第10期40卷 1535-1545页

作者： Bolin Zhang Lifeng Deng Michael Liebau Yingjie Ren Chunyun Luo Bo Liu Shengen Zhang roger Glaser Institute for Advanced Materials and Technology University of Science and Technology BeijingBejing 100083China Shunde Graduate School University of Science and Technology BeijingFoshan 528399China Jiangsu Longkingcotech Co. Ltd.Yancheng224000China Institute of Chemical Technology Universit at LeipzigLeipzig04103Germany

The CeO_(2),Ce-Nb-O_(x) and Nb_(2)O_(5) catalysts were synthesized by citric acid method and the promotion effect of Nb on ceria for selective catalytic reduction(SCR)of NO with NH_(3) was *** catalytic activity measurements indicate that the mixed oxide Ce-Nb-O_(x) presents a higher SCR activity than the single oxide CeO_(2) or Nb_(2)O_(5) *** addition,the Ce-Nb-O_(x) catalyst shows high resistance towards H_(2)O and SO_(2) at 280℃.The Raman,X-ray photoelectron spectra and temperature programmed reduction with H_(2) results indicate that the incorporation of Nb provides abundant oxygen vacancies for capturing more surface adsorbed oxygen,which provides a superior redox capability and accelerates the renewal of active ***,the Fourier transform infrared spectra and temperature programmed desorption of NH_(3) results suggest that niobium pentoxide shows high surface acidity,which is partly retained in the Ce-Nb-O_(x) catalyst possessing a high content of Lewis and Br?nsted acid ***,the incorporation of Nb improves both the redox and acidic capacities of Ce-Nb-O_(x) catalyst for the SCR ***,the redox behavior is primarily taken on Ce and the acidity is well improved by Nb,so the synergistic effect should exist between Ce and *** terms of the reaction mechanism,in situ DRIFT experiments suggest that both NH_(3) on Lewis acid sites and NH_(4)^(+) on Bronsted acid sites can react with NO species,and adsorbed NO and NO_(2) species can both be reduced by NH_(3).In the SCR process,O_(2) primarily acts as the accelerant to improve the redox and acid cycles and plays an important *** work proves that the combination of redox and acidic properties of different constituents can be feasible for catalyst design to obtain a superior SCR performance.

关键词： Cerium-niobium Selective catalytic reduction Redox behavior Acid cycle Synergistic effect Rare earths

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Decision support for the development,simulation and optimization of dynamic process models

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Frontiers of Chemical Science and Engineering 2022年第2期16卷 210-220页

作者： Norbert Asprion roger Böttcher Jan Schwientek Johannes Höller Patrick Schwartz Charlie Vanaret Michael Bortz BASF SE 67063 LudwigshafenGermany Fraunhofer ITWM 67663 KaiserslauternGermany

Simulation is besides experimentation the major method for designing,analyzing and optimizing chemical *** ability of simulations to reflect real process behavior strongly depends on model *** and adaption of process models are usually based on available plant *** such a model in various simulation and optimization studies can support the process designer in his *** steady state models there is also a growing demand for dynamic models either to adapt faster to changing conditions or to reflect batch *** this contribution challenges of extending an existing decision support framework for steady state models to dynamic models will be discussed and the resulting opportunities will be demonstrated for distillation and reactor examples.

关键词： decision support multicriteria optimization model validation dynamic model sensitivity analysis

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Myocardial Oxygenation Response to Stress Performing a Single-set Compared to Volume-Matched Multiple-Set of Leg Press in Untrained Young Adults

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Journal of Science in Sport and Exercise 2023年第2期5卷 174-181页

作者： Junhai Xu arnold G.Nelson James J.Tufano Juntao Wang School of Kinesiology Louisiana State UniversityBaton RougeLouisianaUSA Faculty of Physical Education and Sport Charles UniversityPragueCzech Republic School of Sport Economic and Management Central University of Finance&EconomicsBeijingP.R.China

Background Debates exist about the preference for single-or multiple-set resistance exercise(RE)on achieving similar training outcome,however,no study examined their effects on the heart,thus,this study was to examine the effect of volume-matched single-and multiple-set RE on the myocardial response through examining rate pressure product(RPP).Methods Fourteen healthy untrained college students performed two leg press exercises(4×10 and 1×40 at 150%body mass)on different days,and each was performed twice in a counterbalanced crossover ***-and post-exercise SBP and HR were measured by auscultatory method,RPP was calculated as SBP×HR×10^(-3),RPP difference(RPPdiff)was calcu-lated by post-exercise RPP subtracting pre-exercise *** Single-set post-exercise RPP(17.48±3.16 mmHg·beats/min),HR(123.86±20.25 beats/min)was significantly greater than multiple-set post-exercise RPP(13.66±3.04 mmHg·beats/min),HR(101.61±19.14 beats/min),*** was no significant difference of SBP(141.07±9.37 vs.134.29±15.16 mmHg)between exercise protocols(P=0.13).The RPPdiff of single-set(6.74±2.86 mmHg·beats/min)was significantly greater than that of multiple-set(3.62±2.90 mmHg·beats/min)(P<0.001).Conclusions Single-set RE exerts a greater myocardial oxygenation response as compared to multiple-set,HR contributed more than SBP to the increase of RPP in *** results indicate that single-set RE can be warranted when wanting to train the heart,while multiple-set RE would appear best for those who should avoid heart stress.

关键词： Myocardial oxygen consumption Rate pressure product Heart rate Systolic blood pressure Resistance exercise

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Low Birth Weight in Cameroon: Research and Analysis of Factors Associated with Their Occurrence in Douala Maternity Wards

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Open Journal of Obstetrics and Gynecology 2024年第5期14卷 758-778页

作者： Henri Essome Merlin Boten Bounyom Astrid Ndolo Kondo Ingrid Doriane Ofakem Ilick Charlotte Epossè Ekoube Rita Bono Betoko Hassanatou Iyawa Fulbert Mangala Nkwele Théophile Nana Njamen Robert Tchounzou Alphonse Ngalame Nyong Charlotte Irène Cyrielle Edjoa Mboe Moustapha Bilkissou Junie Ngaha Yaneu Marga Vanina Ngono Akam Gervais Mounchikpou Ngouhouo Grâce Tocki Toutou Michel roger Ekono Nelly Noubi Pascal Foumane Training Teaching and Research Unit in Gynecology Obstetrics and Reproduction Faculty of Medicine and Pharmaceutical Sciences University of Douala Douala Cameroon Laquintinie Hospital Douala Cameroon Faculty of Health Sciences University of Bamenda Bamenda Cameroon Faculty of Health Sciences University of Buea Buea Cameroon Faculty of Medicine and Biomedical Sciences University of Yaound&#233 1 Yaound&#233 Cameroon Faculty of Medicine and Pharmaceutical Sciences University of Ebolowa Ebolowa Cameroon

Introduction: Low birth weight (LBW) is defined by the World Health Organization (WHO) as a birth weight strictly below 2500 g, whatever the term of pregnancy. It constitutes a major public health problem, both in developed and developing countries, due to its magnitude and its strong association with infant morbidity and mortality. Main objective was to study the factors associated with the occurrence of small-for-gestational-age newborns in Douala. Methodology: We carried out a cross-sectional analytical study with prospective data collection using a technical pretested sheet in the maternity wards of the Douala General Hospital, the Laquintinie Hospital, and the District hospitals of Deido, Nylon and Bonassama over a period of 4 months (January to April 2020). We were interested in any newborn, born alive, vaginally or by cesarean section, of low weight, seen in the first 24 hours from a full-term single-fetal pregnancy whose mother had given her consent. Our sampling was consecutive and non-exhaustive. We excluded newborns whose term was unclear and those with congenital malformations or signs of embryo-foetopathy. Data collection was done using survey sheets. Statistical analyzes were carried out with CS Pro 7.3 and SPSS version 25.0 software. The Student, Chi-square and Fischer tests were used to compare the means of the variables, the percentages with a significance threshold P value Results: During the study period, 305 full-term newborns were included, divided into 172 boys and 133 girls. The percentage of small-for-gestational-age newborns was 9.8%;after multivariate analysis by logistic regression to eliminate confounding factors, we found maternal factors associated with small for gestational age newborns;maternal age less than 20 years, primiparity, gestational age (37 - 38), a delay in prenatal visits greater than 14 weeks, anemia in pregnancy, positive toxoplasmosis serology in pregnancy, a body mass index of Conclusion: Our study revealed the potenti

关键词： Newborn Low Birth Weight Gestational Age Douala

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