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Preparation and Alkylation of Carbon Nanofibers from Polymethyl methacrylate

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Journal of materials Science and Chemical Engineering 2024年第9期12卷 55-68页

作者： Stephen mukhebi Situma Geoffrey Otieno austin O. Aluoch Dickson m. Andala James Owour School of Chemistry and material Science Technical University of Kenya Haile Selassie Avenue Nairobi Kenya Chemistry Department Multi-Media University Nairobi Kenya

Carbon nanofibers have revolutionized nanotechnology due to their potential applications in emerging frontiers of research and industrial sectors. This can be attributed to their superior properties such as higher mechanical strength, unique surface characteristics, and improved adherence that is transmitted into the polymer matrix to form a nanocomposite with improved properties. Polymethyl methacrylate is a common carbon source for the synthesis of carbon nanofibres of its high mechanical strength, thermal stability, and low moisture and water absorbing capacity that allows its products to have several applications. In this work, we report the successful electrospinning of carbon nanofibres from Poly methyl methacrylate and functionalizing the resulting carbon nanofibres. The functionalized carbon nanofibres were analyzed to determine their solubility/dispersion in selected organic solvents, then characterized using Fourier transform infra-red spectroscopy, Raman spectroscopy, scanning electron microscopy combined with Energy dispersive spectroscopy and Thermalgravimetric analysis.

关键词： Polymethyl methacrylate Electrospinning Carbon Nanofibres Alkylation

Storylines of family medicine Ⅸ:people and places—diverse populations and locations of care

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Family medicine and Community Health 2024年第S3期12卷 79-88页

作者： William B Ventres Leslie A Stone Emad R Abou-Arab Julio meza David S Buck Jerome W Crowder Jennifer Y C Edgoose Alexander Brown Ellen J Plumb Amber K Norris Jay J Allen Lauren E Giammar John E Wood Scott m Dickson G austin Brown Family and Preventive medicine University of Arkansas for Medical Sciences College of MedicineLittle RockArkansasUSA Family medicine University of Michigan Medical SchoolAnn ArborMichiganUSA Family medicine University of California Los AngelesDavid Geffen School of MedicineLos AngelesCaliforniaUSA Community medicine University of HoustonTilman J Fertitta Family College of MedicineHoustonTexasUSA Social and Behavioral Sciences University of HoustonTilman J Fertitta Family College of MedicineHoustonTexasUSA Family medicine and Community Health University of Wisconsin-Madison School of Medicine and Public HealthMadisonWisconsinUSA NH Dartmouth Family medicine Residency ConcordNew HampshireUSA San Francisco VA medical Center San FranciscoCaliforniaUSA Duluth Family medicine Residency Program University of Minnesota Medical School Duluth CampusDuluthMinnesotaUSA UAmS Northeast Regional Campus Family medicine Residency Program JonesboroArkansasUSA Cascades East Family medicine Residency Program Oregon Health&Science University School of MedicineKlamath FallsOregonUSA

Storylines of Family medicine is a 12-part series of thematically linked mini-essays with accompanying illustrations that explore the many dimensions of family medicine as interpreted by individual family physicians and medical educators in the USA and elsewhere around the ***‘Ⅸ:people and places—diverse populations and locations of care’,authors address the following themes:‘LGBTQIA+health in family medicine’,‘A family medicine approach to substance use disorders’,‘Shameless medicine for people experiencing homelessness’,“Difficult”encounters—finding the person behind the patient’,‘Attending to patients with medically unexplained symptoms’,‘making house calls and home visits’,‘Family physicians in the procedure room’,‘Robust rural family medicine’and‘Full-spectrum family medicine’.may readers appreciate the breadth of family medicine in these essays.

关键词： illustration family dimensions

Investigation of effect of near-fault motions on substandard bridge structures

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Earthquake Engineering and Engineering Vibration 2011年第1期10卷 1-11页

作者： austin Brown m. Saiid Saiidi Dynamic Certification Laboratories Department of Civil & Environmental Engineering

The objective of this study was to investigate the effects of near-fault ground motions on substandard bridge columns and piers. To accomplish these goals, several large scale reinforced concrete models were constructed and tested on a shake table using near- and far-field ground motion records. Because the input earthquakes for the test models had different characteristics, three different measures were used to evaluate the effect of the input earthquake. These measures are peak shake table acceleration, spectral acceleration at the fundamental period of the test specimens, and the specimen drift ratios. For each measure, force-displacement relationships, strains, curvatures, drift ratios, and visual damage were evaluated. Results showed that regardless of the measure of input or response, the near-fault record generally led to larger strains, curvatures, and drift ratios. Furthermore, residual displacements were small compared to those for columns meeting current seismic code requirements.

关键词： near-fault reinforced concrete bridge columns dynamic response

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Compositional Effect of ZrO_2 Nanofillers on a PVDF-co-HFP Based Polymer Electrolyte System for Solid State Zinc Batteries

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Chinese Journal of Polymer Science 2016年第3期34卷 332-343页

作者： m.Johnsi S.austin Suthanthiraraj Department of Energy University of MadrasGuindy Campus

Composite polymer electrolytes（CPEs） comprising poly（vinilydene fluoride-hexafluoro propylene）, PVDF-coHFP and zinc triflate, Zn（CF3SO3）2 with varying concentrations of ZrO_2 nanofillers were prepared by solution casting technique with N,N-dimethyl formamide（DmF） as the common solvent. The polymer electrolyte specimen with the particular composition 75 wt% PVDF-co-HFP： 25 wt% Zn Tf ＋ 7 wt% Zr O2 showed the highest conductivity of 4.6 × 10-4 S/cm at 298 K as confirmed from impedance measurements and favored by the rich amorphous phase of the CPE revealed from room temperature X-ray diffraction analysis（XRD）. The electrical conductivity relaxation time and its distribution within the materials have been evaluated from the electric modulus m 2 and impedance Z＂ data which showed the occurrence of non-Debye type of relaxation phenomenon. The changes in the surface morphology of the CPEs were examined using scanning electron microscopy（SEm）. The electrochemical stability window of CPE is found to be 2.6 V with a thermal stability up to 300 °C. An electrochemical cell has been fabricated based on Zn/mnO_2 electrode couple under a constant load of 1 mΩ and its discharge characteristics have been evaluated.

关键词： Nanocomposites Dielectric properties Thermal stability Electrochemical stability Batteries

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A unified fractional flow framework for predicting the liquid holdup in two-phase pipe flows

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Petroleum Science 2024年第4期21卷 2614-2624页

作者： Fuqiao Bai Yingda Lu mukul m.Sharma Hildebrand Department of Petroleum and Geosystems Engineering The University of Texas at Austin

Two-phase pipe flow occurs frequently in oil & gas industry, nuclear power plants, and CCUS. Reliable calculations of gas void fraction(or liquid holdup) play a central role in two-phase pipe flow models. In this paper we apply the fractional flow theory to multiphase flow in pipes and present a unified modeling framework for predicting the fluid phase volume fractions over a broad range of pipe flow conditions. Compared to existing methods and correlations, this new framework provides a simple,approximate, and efficient way to estimate the phase volume fraction in two-phase pipe flow without invoking flow patterns. Notably, existing correlations for estimating phase volume fraction can be transformed and expressed under this modeling framework. Different fractional flow models are applicable to different flow conditions, and they demonstrate good agreement against experimental data within 5% errors when compared with an experimental database comprising of 2754 data groups from 14literature sources, covering various pipe geometries, flow patterns, fluid properties and flow *** gas void fraction predicted by the framework developed in this work can be used as inputs to reliably model the hydraulic and thermal behaviors of two-phase pipe flows.

关键词： Pipe fractional flow Liquid holdup multiphase pipe flow Gas void fraction

Direct measurements of the Electron Energy Flux versus Electron Temperature Gradient in Tokamak Discharges

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Plasma Science and Technology 2004年第1期6卷 2130-2134页

作者： K.W.Gentle m.E.austin P.E.Phillips Fusion Research Center University of Texas USAFusion Research Center University of Texas USAFusion Research Center University of Texas USA

Electron thermal transport is one of the most complex processes in fusionplasmas. It is generally described by a simple thermal diffusivity in transport analyses ofdischarges, but there is evidence of critical gradient effects with moderate stiffness. By analyzingperiodic perturbations to an equilibrium, one canmeasure the variations in electron energy flux andelectron temperature gradient over the perturbation cycle, obtaining the flux as a function ofgradient over the range of parameters generated by the perturbation. Although time-dependenttransport analysis is very sensitive to noise in the input data, averaging over many cycles of aperiodic perturbation can provide data of sufficient quality. The analyses presented here are basedon the ECE temperature data with high spatial and temporal resolution and full profile coverage onDIII-D for sawteeth and modulated ECH heating.

关键词： tokamak discharges electron energy flux electron temperature gradient direct measurements

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Is the propensity to emit alarm calls associated with health status?

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Current Zoology 2020年第6期66卷 607-614页

作者： austin L.Nash Alexandra H.m.Jebb Daniel T.BLUmSTEIN Department of Ecology and Evolutionary Biology University of Colorado265 UCBBoulderCO 80309USA School of Biological Sciences University of AberdeenZoology BuildingTillydrone AvenueAberdeenAB242TZUK The Rocky mountain Biological Laboratory Box 519 Crested ButteCO 81224USA Department of Ecology and Evolutionary Biology University of California621 Young Drive SouthLos AngelesCA 90095-1606USA

The production and structure of animal signals may depend on an individual's health status and may provide more than one type of information to *** alarm calls are not typically viewed as health condition dependent,recent studies have suggested that their structure,and possibly their propensity to be emitted,depends on an individual,s health condition and *** asked whether the propensity of yellow-bellied marmots(marmota flaviventer)to emit calls is influen ced by their immuno logical or parasite status,by quantifying both trap-elicited and n atural calling rates as a function of their neutrophil-to-lymphocyte(NL)ratio,the presence of a blood borne trypanosome,and the presenee of several intestinal parasites(Eimeria sp.,Entamoeba sp.,and Ascaris sp.).We fitted mixed effects models to determine if the health measures we collected were associated with the probability of calling in a trap and with annual rates of natural alarm *** infected with a blood-borne trypanosome were marginally more likely to call naturally and when trapped,while those infected with the intestinal parasite Ascaris were less likely to call when *** ratio was not directly associated with in-trap calling probability,but males were more likely to call when they had higher NL ***,health conditions,such as parasite infection and immune system activation,can modulate the production of alarm signals and potentially provide in formation to both predators and prey about the caller's *** experiments are required to confirm if receivers use such information.

关键词： alarm calling animal communication antipredator behavior condition dependenee immune function parasites

Anatomically realistic multiscale models of normal and abnormal gastrointestinal electrical activity

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World Journal of Gastroenterology 2007年第9期13卷 1378-1383页

作者： Leo K Cheng Rie Komuro Travis m austin martin L Buist Andrew J Pullan Bioengineering Institute The University of Auckland Private Bag 92019 Auckland 1142 New Zealand Division of Bioengineering National University of SingaporeSingapore Bioengineering Institute The University of Auckland Private Bag 92019 Auckland 1142 New ZealandDepartment of Engineering Science The University of Auckland

One of the major aims of the International Union of Physiological Sciences (IUPS) Physiome Project is to develop multiscale mathematical and computer models that can be used to help understand human health. We present here a small facet of this broad plan that applies to the gastrointestinal system. Specifically, we present an anatomically and physiologically based modelling framework that is capable of simulating normal and pathological electrical activity within the stomach and small intestine. The continuum models used within this framework have been created using anatomical information derived from common medical imaging modalities and data from the Visible Human Project. These models explicitly incorporate the various smooth muscle layers and networks of interstitial cells of Cajal (ICC) that are known to exist within the walls of the stomach and small bowel. Electrical activity within individual ICCs and smooth muscle cells is simulated using a previously published simplified representation of the cell level electrical activity. This simulated cell level activity is incorporated into a bidomain representation of the tissue, allowing electrical activity of the entire stomach or intestine to be simulated in the anatomically derived models. This electrical modelling framework successfully replicates many of the qualitative features of the slow wave activity within the stomach and intestine and has also been used to investigate activity associated with functional uncoupling of the stomach.

关键词： model Bidomain Simulation Interstitial cells of Cajal Physiome GIOIE

Effects of concentration, distance, and application methods of Altriset （Chlorantraniliprole） on eastern subterranean termite （Isoptera： Rhinotermitidae）

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Insect Science 2015年第3期22卷 451-460页

作者： Znar Barwary austin Gorzlancyk Xing Ping Hu Department of Entomology and Plant Pathology Auburn University Auburn AL 36849-5413 USA

The effects of various concentrations, distance, and application methods of Altriset （Chlorantraniliprole） were investigated against one of the most destructive termites, the eastem subterranean termite, Reticulitermesflavipes Kollar. Three laboratory experiments were conducted. First, we examined the concentration effect of treating the soil contiguously to established foraging tunnels at a fixed 1 m distance. The results demonstrated 100% termite control in 19 d posttreatment at 100 and 50μg/g and 27% termite mortality at 25μg/g. Second, we tested the distance effect of the soil treatment （2 and 4 m） on the efficacy of Altriset to the satellite termite populations at a fixed 50/zg/g concentration. This resulted in 100% termite control in 22 d posttreatment at both 2 and 4 m. Third, we examined the effect of differing application methods using 12.5 and 25μg/g prior to the establishment of foraging tunnels at a fixed 1 m distance. This illustrated 100% termite control in 9 d posttreatment at 25μg/g and 12 d posttreatment at 12.5μg/g. The third experiment demonstrated soil treatments that were applied prior to termite tunnel establishment had greater efficacy than applications made post tunnel construction. Our results provide a comprehensive understanding about the efficacy of Altriset treatments on eastern subterranean termites.

关键词： application methods Chlorantraniliprole concentration effect distance effect Reticulitermesflavipes soil treatment