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Fibre Treatment Uniformity in Pulp Refining

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Paper And Biomaterials 2018年第3期3卷 1-6页

作者： Richard j.Kerekes j.david mcdonald Pulp and Paper Centre The University of British ColumbiaVancouverV6T 1Z4Canada jDMcD Consulting Inc. Vaudreuil-DorionQuebecJ7V 0G1Canada

This paper explores implications of previous work which suggested that pulp refining is achieved by a small number of *** a consequence,the purpose of multiple bar crossings in refiners is to expose many fibres to a few effective cycles,not to impose many cycles on each *** on this postulate,tensile strength increase was found to be well described by a cumulative probability equation having two parameters:(a) number of bar crossings and(b) probability of a successful refining outcome at each *** this paper,this concept further with additional refiner data was explored and the link between the probability term and measurable refiner variables was *** proposing the possibility,these two parameters may be a desirable alternative to specific energy and specific edge load for characterizing refining action.

关键词： pulp refining refining uniformity tensile strength refining characterization

Characterization and catalytic behavior of EDTA modified silica nanosprings (NS)-supported cobalt catalyst for Fischer-Tropsch CO-hydrogenation

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燃料化学学报 2018年第8期46卷 957-966页

作者： Abdulbaset M.Alayat Elena Echeverria david N.Mcllroy Armando G.mcdonald Environmental Science University of IdahoMoscowID83844-3006United States Renewable Materials Program Department of Forest Rangeland and Fire Sciences University of IdahoMoscow ID 83844-1133 United States Department of Physics Oklahoma S

The effect of ethylene diamine tetraacetic acid(EDTA) modification on the physico-chemical properties and catalytic performance of silica nanosprings(NS) supported cobalt(Co) catalyst was investigated in the conversion of syngas(H^(2+) CO) to hydrocarbons by Fischer-Tropsch synthesis(FTS). The unmodified Co/NS and modified Co/NS-EDTA catalysts were synthesized via an impregnation method. The prepared Co/NS and Co/NS-EDTA catalysts were characterized before the FTS reaction by BET surface area,X-ray diffraction(XRD),transmission electron microscopy(TEM),temperature programmed reduction(TPR),X-ray photoelectron spectroscopy(XPS),differential thermal analysis(DTA) and thermogravimetric analysis(TGA) in order to find correlations between physico-chemical properties of catalysts and catalytic performance. FTS was carried out in a quartz fixedbed microreactor(H_2/CO of 2 ∶1,230 ℃ and atmospheric pressure) and the products trapped and analyzed by GC-TCD and GC-MS to determine CO conversion and reaction selectivity. The experimental results indicated that the modified Co/NS-EDTA catalyst displayed a more-dispersed phase of Co_3O_4 nanoparticles(10.9%) and the Co_3O_4 average crystallite size was about 12.4 nm. The EDTA modified catalyst showed relatively higher CO conversion(70.3%) and selectivity toward C_(6-18)(jP-8,jet A and diesel) than the Co/NS catalyst(C_(6-14))(jP-4).

关键词：化学分析煤矿燃烧

Bone loss from Wnt inhibition mitigated by concurrent alendronate therapy

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Bone Research 2018年第2期6卷 167-176页

作者： Babita Madan Mitchell j.mcdonald Gabrielle E.Foxa Cassandra R.Diegel Bart O.Williams david M.Virshup Program in Cancer and Stem Cell Biology Duke-NUS Medical School Center for Cancer and Cell Biology and Program for Skeletal Disease and Tumor Microenvironment Van Andel Research Institute Department of Pediatrics Duke University

Dysregulated Wnt signaling is associated with the pathogenesis of cancers, fibrosis, and vascular diseases. Inhibition of Wnt signaling has shown efficacy in various pre-clinical models of these disorders. One of the key challenges in developing targeted anti-cancer drugs is to balance efficacy with on-target toxicity. Given the crucial role Wnts play in the differentiation of osteoblasts and osteoclasts, acute inhibition of Wnt signaling is likely to affect bone homeostasis. In this study, we evaluated the skeletal effect of small molecule inhibitor of an o-acyl transferase porcupine（PORCN） that prevents Wnt signaling by blocking the secretion of all Wnts. Micro-computed tomography and histomorphometric evaluation revealed that the bones of mice treated with two structurally distinct PORCN inhibitors LGK974 and ETC-1922159（ETC-159） had loss-of-bone volume and density within 4 weeks of exposure. This decreased bone mass was associated with a significant increase in adipocytes within the bone marrow. Notably,simultaneous administration of a clinically approved anti-resorptive, alendronate, a member of the bisphosphonate family,mitigated loss-of-bone mass seen upon ETC-159 treatment by regulating activity of osteoclasts and blocking accumulation of bone marrow adipocytes. Our results support the addition of bone protective agents when treating patients with PORCN *** of bone toxicity can extend the therapeutic utility of Wnt pathway inhibitors.

关键词： Wnt ETC Bone loss Wnt inhibition mitigated concurrent alendronate therapy

Preliminary Insights into the Habitat Preferences of the Centralian Bandy Bandy (Vermicella vermiformis)(Squamata: Elapidae) in Central Australia

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Asian Herpetological Research 2014年第1期5卷 49-53页

作者： Peter j.mcdonald Gary W.LUCK Flora and Fauna Division Department of Land Resource Management Northern Territory Government School of Environmental Sciences Charles Sturt University Institude for Land Water and Society Charles Sturt University

Bandy Bandy’s（Vermicella spp.）are a striking,black-and-white ringed genus of small elapid snakes endemic to *** taxa are burrowers and little is known of their biology and *** investigated the habitat preferences of the only arid-dwelling species,the centralian bandy bandy（Vermicella vermiformis）,in the MacDonnell Ranges west of Alice Springs in the Northern *** systematic road-cruising,we encountered *** over a 12 months period between 2009 and *** used logistic regression to model the occurrence of the species against a range of different habitat variables collected at multiple *** the small sample size,*** exhibited a clear preference for acacia shrubland habitats,with acacia variables present in all AICc ranked models in the 95%confidence *** factors driving this association,together with the preference for habitat not burnt in the most recent wildfires,may be related to the abundance of their only known prey,blind snakes（Ramphotyphlops spp.）.

关键词： Snake Arid Acacia Fire Ramphotyphlops

Decreased bioavailability of aminomethylphosphonic acid(AMPA)in genetically modified corn with activated carbon or calcium montmorillonite clay inclusion in soil

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journal of Environmental Sciences 2021年第2期33卷 131-143页

作者： Sara E.Hearon Meichen Wang Thomas j.mcdonald Timothy D.Phillips Veterinary Integrative Biosciences Department College of Veterinary Medicine and Biomedical Sciences Texas A&M Uniuersity College StationTx 77845USA Department of Environmental and Occupational Health School of Public Health Texas A&M UniversityCollege Station400 Bizzell St College StationTX 77843USA

The widespread use of pesticides has resulted in detectable residues throughout the environment,sometimes at concentrations well above regulatory ***,the development of safe,effective,field-practical,and economically feasible strategies to mitigate the effects of pesticides is *** is an organophosphorus herbicide that is degraded to aminomethylphosphonic acid(AMPA),a toxic and persistent metabolite that can accumulate in soil and sediment and translocate to *** this study,we investigated the binding efficacy of activated carbon(AC)and calcium montmorillonite(CM)clay to decrease AMPA bioavailability from soil and AMPA translocation to *** isotherms and thermodynamic studies on AC and CM were conducted and showed tight binding(enthalpy values>-20 k j/mol)for AMPA with high capacities(0.25 mol/kg and 0.38 mol/kg,respectively),based on derivations from the Langmuir model.A hydra assay was utilized to indicate toxicity of AMPA and the inclusion of 1%AC and CM both resulted in 90%protection of the hydra(**p≤0.01).Further studies in glyphosate-contaminated soil showed that AC and CM significantly reduced AMPA bioavailability by 53%and 44%,*** in genetically modified(GM)corn showed a conversion of glyphosate to AMPA in roots and sprouts over a 10-day exposure *** of AC and CM reduced AMPA residues in roots and sprouts by 47%-61%.These studies collectively indicate that AC and CM are effective sorbents for AMPA and could be used to reduce AMPA bioavailability from soil and AMPA residues in GM corn plants.

关键词： Glyphosate AMPA Activated carbon Calcium montmorillonite Sorbent

4D imaging of void nucleation,growth,and coalescence from large and small inclusions in steel under tensile deformation

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journal of Materials Science & Technology 2022年第28期123卷 168-176页

作者： Yi Guo Timothy L.Burnett Samuel A.mcdonald Michael Daly Andrew H.Sherry Philip j.Withers Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Henry Royce Institute Department of MaterialsUniversity of ManchesterM139PLUK European Synchrotron Radiation Facility(ESRF) 6 rue J Horowitz38000 GrenobleFrance National Nuclear Laboratory Chadwick HouseBirchwood ParkWarringtonWA36AEUK

Samples of SA508 grade 3 nuclear pressure vessel ferritic steel were subjected to tensile straining whilst being simultaneously imaged in 3D in real time using high resolution,high frame rate time-lapse synchrotron computed tomography(CT).This enabled direct observation of void development from nucleation,through growth to coalescence and final failure validating many inferences made post-mortem or by theoretical models,as well as raising new *** sparse,large inclusions were found to nucleate voids at essentially zero plastic strain(consistent with zero interfacial strength);these became increasingly elongated with *** contrast,a high density of small spherical voids were found to nucleate from the sub-micron cementite particles at larger strains(>200%)only in the centre of the necked(high triaxiality)*** interfacial strength approaching 2100 MPa was inferred and soon after their nucleation,these small voids coalesce to form internal microcracks that lead to the final failure of the *** surprisingly,under these conditions of generally low triaxial constraint the large voids are simply cut across and appear to play no significant role in determining the final *** implications of these results are discussed in terms of ductile fracture behaviour and the Gurson model for ductile fracture.

关键词： Void growth Ductile fracture Synchrotron X-ray tomography 4D imaging Bainitic steel

Post-weaning and whole-of-life performance of pigs is determined by live weight at weaning and the complexity of the diet fed after weaning

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Animal Nutrition 2017年第4期3卷 372-379页

作者： Cherie L.Collins john R.Pluske Rebecca S.Morrison Trevor N.mcdonald Robert j.Smits david j.Henman Ingunn Stensland Frank R.Dunshea Rivalea Australia Pty Ltd School of Veterinary and Life Sciences Murdoch University Faculty of Veterinary and Agricultural Sciences The University of Melbourne

The production performance and financial outcomes associated with weaner diet complexity for pigs of different weight classes at weaning were examined in this experiment. A total of 720 weaner pigs(360 entire males and 360 females) were selected at weaning(27 ± 3 d) and allocated to pens of 10 based on individual weaning weight(light weaning weight: pigs below 6.5 kg; medium weaning weight: 6.5 to8 kg; heavy weaning weight: above 8.5 kg). Pens were then allocated in a 3 x 2 x 2 factorial arrangement of treatments with the respective factors being weaning weight(heavy, medium and light; H, M and L,respectively), weaner diet complexity(high complexity/cost, HC; low complexity/cost, LC), and gender(male and female). Common diets were fed to both treatment groups during the final 4 weeks of the weaner period(a period of 39 days). In the first 6 d after weaning, pigs offered the HC diets gained weight faster and used feed more efficiently than those offered the LC diets(P = 0.031). Pigs fed a HC diet after weaning tended to be heavier at the sale live weight of 123 d of age compared with pigs fed the LC diet(P = 0.056). There were no other main effects of the feeding program on growth performance through to slaughter. Weaning weight had a profound influence on lifetime growth performance and weight at 123 d of age, with H pigs at weaning increasing their weight advantage over the M and L pigs(101.3,97.1, 89.6 kg respectively, P < 0.001). Cost-benefit analyses suggested there was a minimal benefit in terms of cost per unit live weight gain over lifetime when pigs were offered a HC feeding program to L,with a lower feed cost/kg gain. The results from this investigation confirm the impact of weaning weight on lifetime growth performance, and suggest that a HC feeding program should be focused on L weaner pigs(i.e., weaning weight less than 6.5 kg at 27 d of age) in order to maximise financial returns.

关键词： Pigs Performance Diet complexity Weaning weight Carcass characteristics Cost benefit analyses

Elimination of antibiotic resistance genes and control of horizontal transfer risk by UV-based treatment of drinking water: A mini review

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Frontiers of Environmental Science & Engineering 2019年第3期13卷 3-11页

作者： Virender K.Sharma Xin Yu Thomas j.mcdonald Chetan jinadatha Dionysios D.Dionysiou Mingbao Feng Department of Environmental and Occupational Health School of Public Health Texas A&M University College Station TX 77843 USA Institute of Urban Environment Chinese Academy of Sciences Xiamen 361021 China Central Texas Veterans Health Care System Temple TX 76504 USA College of Medicine Texas A&M Health Science Center Bryan TX 77807 USA Environmental Engineering and Science Program Department of Chemical and Environmental Engineering (DChEE) 705 Engineering Research Center University of Cincinnati Cincinnati OH 45221 USA

Antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) have been recognized as one of the biggest public health issues of the 21 st century. Both ARB and ARGs have been determined in water after treatment with conventional disinfectants. Ultraviolet (UV) technology has been seen growth in application to disinfect the water. However, UV method alone is not adequate to degrade ARGs in water. Researchers are investigating the combination of UV with other oxidants (chlorine, hydrogen peroxide (H2O2), peroxymonosulfate (PMS), and photocatalysts) to harness the high reactivity of produced reactive species (C1-, C1O -, Cl2-,-OH, and SO4-_) in such processes with constituents of cell (e.g., deoxyribonucleic acid (DNA) and its components) in order to increase the degradation efficiency of ARGs. This paper briefly reviews the current status of different UV-based treatments (UV/chlorination, UV/H2O2, UV/PMS, and UV-photocatalysis) to degrade ARGs and to control horizontal gene transfer (HGT) in water. The review also provides discussion on the mechanism of degradation of ARGs and application of q-PCR and gel electrophoresis to obtain insights of the fate of ARGs during UV-based treatment processes.

关键词： Antibiotic resistance bacteria Advanced oxidation processes Disinfection Reactive chlorine species Sulfate radicals Reactive oxygen species

A bayesian optimisation methodology for the inverse derivation of viscoplasticity model constants in high strain-rate simulations

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Defence Technology（防务技术） 2022年第9期18卷 1563-1577页

作者： Shannon Ryan julian Berk Santu Rana Brodie mcdonald Svetha Venkatesh Applied Artificial Intelligence Institute(A^(2)I^(2)) Deakin University75 Pigdons RdWaurn PondsVIC3216Australia Defence Science and Technology Group 506 Lorimer StreetFishermans BendVIC3207Australia

We present an inverse methodology for deriving viscoplasticity constitutive model parameters for use in explicit finite element simulations of dynamic processes using functional experiments, i.e., those which provide value beyond that of constitutive model development. The developed methodology utilises Bayesian optimisation to minimise the error between experimental measurements and numerical simulations performed in LS-DYNA. We demonstrate the optimisation methodology using high hardness armour steels across three types of experiments that induce a wide range of loading conditions: ballistic penetration, rod-on-anvil, and near-field blast deformation. By utilising such a broad range of conditions for the optimisation, the resulting constitutive model parameters are generalised, i.e., applicable across the range of loading conditions encompassed the by those experiments(e.g., stress states, plastic strain magnitudes, strain rates, etc.). Model constants identified using this methodology are demonstrated to provide a generalisable model with superior predictive accuracy than those derived from conventional mechanical characterisation experiments or optimised from a single experimental condition.

关键词： Constitutive modelling Finite element Bayesian optimisation Finite element model updating