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The influence of airtightness on contaminant spread in mURbs in cold climates

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building simulation 2022年第2期15卷 249-264页

作者： Philip mckeen Zaiyi Liao Department of Architectural science Ryerson UniversityTorontoM5B2K3Canada

Tall buildings in cold climates have unique challenges in maintaining indoor air quality due to stack *** the heating season,interior air buoyancy creates large pressure differentials in vertical shafts that can drive airflow from lower floors into upper *** pressure differential can result in the spread of contaminants throughout a *** recently,concern over COVID-19 has increased attention to the potential spread of airborne diseases in densely populated *** many multi-unit residential buildings,suite ventilation has traditionally relied upon fresh air supplied through a mechanically pressurized *** cold climates,large pressure differentials created by stack-effect can reduce the effectiveness of this *** and CFD simulations are employed to analyze airflow and contaminant spread due to stack *** are conducted on an idealized model of a 10-storey building using a range of experimentally derived airtightness *** demonstrate stack effect can reduce corridor ventilation to suites and even reverse the airflow for leakier *** airflow to suites can result in the accumulation of *** of the airflow can allow contaminants from a suite to spread throughout the *** spread is illustrated as a function of mechanical ventilation,building airtightness,and ambient *** to reduce the influence of stack effect on mechanically pressurized corridors are discussed.

关键词： mURbs ventilation contamination spread stack effect

Use of endoscopic ultrasound-guided gallbladder drainage as a rescue approach in cases of unsuccessful biliary drainage

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World Journal of Gastroenterology 2024年第1期30卷 70-78页

作者： Alessandro Fugazza Kareem Khalaf Katarzyna m Pawlak marco spadaccini matteo Colombo marta Andreozzi marco Giacchetto silvia Carrara Chiara Ferrari Cecilia binda benedetto mangiavillano Andrea Anderloni Alessandro Repici Division of Gastroenterology and Digestive Endoscopy Humanitas Research Hospital-IRCCSRozzano 20089MilanoItaly Division of Gastroenterology St.Michael’s HospitalUniversity of TorontoToronto M5B 1W8ONCanada Department of Anesthesia Humanitas Research Hospital-IRCCSRozzano 20089MilanoItaly Gastroenterology and Digestive Endoscopy Unit Forlì-Cesena HospitalsRomagna 47121Italy Gastrointestinal Endoscopy Unit Humanitas Mater DominiCastellanza 21100Italy Gastroenterology and Digestive Endoscopy Unit Fondazione IRCCS Policlinico San MatteoPavia 27100Italy

This narrative review provides an overview of the utilization of endoscopic ultrasound-guided gallbladder drainage(EUs-GbD)as a salvage approach in cases of unsuccessful conventional ***-GbD is a minimally invasive and effective technique for drainage in patients with acute cholecystitis with high risk of *** procedure has demonstrated impressive technical and clinical success rates with low rates of adverse events,making it a safe and effective option for appropriate ***,EUs-GbD can also serve as a rescue option for patients who have failed endoscopic retrograde cholangiopancreatography or EUs biliary drainage for relief of jaundice in malignant biliary ***,patient selection is critical for the success of EUs-GbD,and proper patient selection and risk assessment are important to ensure the safety and efficacy of the *** the field continues to evolve and mature,ongoing research will further refine our understanding of the benefits and limitations of EUs-GbD,ultimately leading to improved outcomes for patients.

关键词： Endoscopic ultrasound-guided gallbladder drainage Gallbladder drainage Acute cholecystitis malignant obstruction Interventional endoscopic ultrasound Lumen-apposing metal stents

Idempotent Completions of Operator Partial matrices

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Acta mathematica sinica,English series 1999年第3期15卷 333-346页

作者： Heydar Radjavi Peter Rosenthal Department of mathematics Shanxi Teachers University Linfen 041004 P. R. ChinaDepartment of Mathematics Statistics and Computing Science Dalhousie University Halifax N.S. B3H 3J5 Canada Department of mathematics University of Toronto Toronto On M5S 1A1 Canada

Necessary and sufficient conditions are obtained for operator partial 2×2 matrices to have an idempotent completion, and all such completions are parametrically represented.

关键词： Hilbert space Operator matrix Idempotent operator

Effects of single-tree selection harvesting on hymenopteran and saproxylic insect assemblages in the canopy and understory of northern temperate forests

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Journal of Forestry Research 2012年第2期23卷 275-284页

作者： sandy m. smith Nurul Islam m. Isabel bellocq Faculty of Forestry University of Toronto 33 Willcocks St. Toronto Ontario M5S 3B3 Canada Departamento de Ecología Genética y Evolución FCEN Universidad de Buenos Aires CONICET. Ciudad Universitaria Pab 2 Piso 4 Buenos Aires 1426 Argentina

Insects respond to changes in microhabitat caused by canopy disturbance, and thus can be used to examine the ecological impacts of harvesting. single-tree selection harvesting is the most common silvicultural system used to emulate local small-scale natural disturbance and maintain uneven-aged forest structure in temperate forests. Here, we test for differences in richness, abundance, and composition of hymenopteran and saproxylic insect assemblages at four different taxon levels （selected insect orders; and all hymenopteran families, and braconid subfamilies and morphospecies） between the canopy and understory of unharvested and single-tree selection harvested sites in a northern temperate forest from central Canada. Harvesting had no effect on insect assemblage richness, composition or abundance at the three highest taxon levels （order, family and subfamily）. similarly, richness and abundance at the lowest-taxon level （braconid morphospecies） were similar, although composition differed slightly between unharvested and harvested stands. Insect assemblages were vertically stratified, with generally higher abundance （for Diptera, Hymenoptera, some hymenopteran families and braconid subfamilies） and richness （for braconid morphospecies） in the understory than the canopy. In particular, composition of the braconid morphospecies assemblage showed relatively low similarity between the understory and canopy. single-tree selection harvesting appears to influence wood-associated insect taxa only subtly through small changes in community composition at the lowest taxon level, and thus is recommended as a conservative approach for managing these northern temperate forests.

关键词： selection harvesting insect communities canopy insects Jack pine forests forest management high-taxon level insect conserva-tion

Grouping tree species to estimate basal area increment in temperate multispecies forests in Durango,mexico

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Forest Ecosystems 2024年第1期11卷 1-13页

作者： Jaime Roberto Padilla-martínez Carola Paul Kai Husmann Jose Javier Corral-Rivas Klaus von Gadow Department of Forest Economics and sustainable Land-use Planning Faculty of Forest Sciences and Forest EcologyUniversity of GottingenBüsgenweg 137077GottingenGermany Facultad de Ciencias Forestales Universidad Juarez del Estado de DurangoRío Papaloapan y Boulevard Durango S/N34120DurangoMexico Faculty of Forestry and Forest Ecology Georg-August-UniversitatBüsgenweg 537077GottingenGermany Department of Forestry and Wood science Faculty of AgriSciencesStellenbosch UniversityStellenbosch Private Bag X1Stellenbosch7602South Africa

multispecies forests have received increased scientific attention,driven by the hypothesis that biodiversity improves ecological ***,a greater species diversity presents challenges for forest management and *** study aims to develop basal area growth models for tree species *** analysis is based on a dataset of 423 permanent plots(2,500 m^(2))located in temperate forests in Durango,***,we define tree species cohorts based on individual and neighborhood-based variables using a combination of principal component and cluster ***,we estimate the basal area increment of each cohort through the generalized additive model to describe the effect of tree size,competition,stand density and site *** principal component and cluster analyses assign a total of 37 tree species to eight cohorts that differed primarily with regard to the distribution of tree size and vertical position within the *** generalized additive models provide satisfactory estimates of tree growth for the species cohorts,explaining between 19 and 53 percent of the total variation of basal area increment,and highlight the following results:i)most cohorts show a"rise-and-fall"effect of tree size on tree growth;ii)surprisingly,the competition index"basal area of larger trees"had showed a positive effect in four of the eight cohorts;iii)stand density had a negative effect on basal area increment,though the effect was minor in medium-and high-density stands,and iv)basal area growth was positively correlated with site quality except for an oak *** developed species cohorts and growth models provide insight into their particular ecological features and growth patterns that may support the development of sustainable management strategies for temperate multispecies forests.

关键词： Temperate multispecies forests Cluster analysis basal area increment Generalized additive models

Exploring one material for dual applications:A red-emitting mg2GeO4:Eu3+ nanophosphor for future generation energy efficient WLEDs and dosimetric applications

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Journal of Rare Earths 2024年第10期42卷 1835-1845页

作者： Akshay Arjun G.P.Darshan s.C.sharma H.Nagabhushana D.V.sunitha H.b.Premkumar Department of Physics Faculty of Mathematical and Physical SciencesM.S.Ramaiah University of Applied Sciences Jain University C.N.R.Rao Centre for Advanced materials Tumkur University school of Applied sciences (Physics) REVA University

The envisaged design and developme nt of individual mate rials to excavate a broader spectrum of desired properties and offer multiple applications are highly *** this in mind,a series of forsterite-structured mg2GeO4:Eu3+（1 mol%-9 mol%） nanophosphors was synthesized via a solution combustion method using oxalyl dihydrazide as a *** X-ray diffraction patterns confirm the orthorhombic crystal system with a Puma space *** results clearly show irregularly shaped cluster-like structures with aggregation of the *** diffuse reflectance spectra,the optical energy band gap of the mg2GeO4:Eu3+（1 mol%-9 mol%） nanophosphors was estimated and obtained to be～4.12-4.32 *** photoluminescence emission spectra exhibit intense peaks at ～579,589,610,661,and 707 nm,which are due to characteristic5D0→7F0,5D0→7F1,5Do→7F2,5D0→7F3and5D0→7F4transitions of Eu3+ions,*** Commission International de L'Eclairage color coordinates are gradually tuned from pale red（0.5980,0.4012） to a pure red（0.6385,0.3611） *** glow peaks showcase excellent super-linear response at low doses of γ-irradiations,indicating that the prepared phosphor can be used in thermoluminescent personal dosimetry which is a biological tissue *** aforementioned results demonstrate that the prepared mg2GeO4:Eu3+（1 mol%-9 mol%） nanophosphors are considered an excellent candidate for dual applications,i.e.,red component in future generation white-light-emitting diodes（WLEDs） and personal dosimetric applications.

关键词： Dosimetry Nanophosphors Photoluminescence Photometric properties Rare earths Thermoluminescence

Topology optimization and seismic collapse assessment of shape memory alloy(smA)-braced frames:Effectiveness of Fe-based smAs

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Frontiers of structural and Civil Engineering 2022年第3期16卷 281-301页

作者： Aydin HAssANZADEH saber mORADI Department of Civil Engineering Ryerson UniversityToronto M5B 2K3Canada

This paper presents a seismic topology optimization study of steel braced frames with shape memory alloy(smA)*** smA-braced frames(smA-bFs)with either Fe-based smA or NiTi braces are determined in a performance-based seismic design *** topology optimization is performed on 5-and 10-story smA-bFs considering the placement,length,and cross-sectional area of smA bracing ***,strength,and performance-based design constraints are considered in the *** seismic response and collapse safety of topologically optimal smA-bFs are assessed according to the FEmA P695 methodology.A comparative study on the optimal smA-bFs is also presented in terms of total relative cost,collapse capacity,and peak and residual story *** results demonstrate that Fe-based smA-bFs exhibit higher collapse capacity and more uniform distribution of lateral displacement over the frame height while being more cost-effective than NiTi braced *** addition to a lower unit price compared to NiTi,Fe-based smAs reduce smA material *** frames with Fe-based smA braces,the smA usage is reduced by up to 80%.The results highlight the need for using smAs with larger recoverable strains.

关键词： topology optimization shape memory alloy Fe-based smA steel braced frames performance-based seismic design collapse assessment

Crosslinked hydrogels--a promising class of insoluble solid molecular dispersion carriers for enhancing the delivery of poorly soluble drugs

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Acta Pharmaceutica sinica b 2014年第1期4卷 26-36页

作者： Dajun D.sun Ping I.Lee Department of Pharmaceutical sciences Leslie Dan Faculty of PharmacyUniversity of TorontoToronto M5S 3M2OntarioCanada

Water-insoluble materials containing amorphous solid dispersions(AsD)are an emerging category of drug carriers which can effectively improve dissolution kinetics and kinetic solubility of poorly soluble *** based on water-insoluble crosslinked hydrogels have unique features in contrast to those based on conventional water-soluble and water-insoluble *** example,solid molecular dispersions of poorly soluble drugs in poly(2-hydroxyethyl methacrylate)(PHEmA)can maintain a high level of supersaturation over a prolonged period of time via a feedback-controlled diffusion mechanism thus avoiding the initial surge of supersaturation followed by a sharp decline in drug concentration typically encountered with AsDs based on water-soluble *** creation of both immediate-and controlled-release AsD dosage forms is also achievable with the PHEmA based *** far,AsD systems based on glassy PHEmA have been shown to be very effective in retarding precipitation of amorphous drugs in the solid state to achieve a robust physical *** review summarizes recent research efforts in investigating the potential of developing crosslinked PHEmA hydrogels as a promising alternative to conventional water-soluble AsD carriers,and a related finding that the rate of supersaturation generation does affect the kinetic solubility profiles implications to hydrogel based AsDs.

关键词： Amorphous solid dispersions Crosslinked hydrogels Poly(2-hydroxyethylmethacrylate) supersaturation Kinetic solubility

Investigation of dense slurry suspensions with coaxial mixers:Influences of design variables through tomography and mathematical modelling

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Particuology 2022年第6期20卷 1-16页

作者： Prakash mishra Farhad Ein-mozaffari Department of Chemical Engineering Ryerson UniversityTorontoM5B 2K3Canada

The coaxial mixers enhance the suspension of concentrated slurries in an agitated *** this research work,the complex slurry suspension and dissemination behavior in a coaxial slurry mixing system(comprised of a close clearance anchor rotating with a low speed and an inner axial impeller rotating with a high speed)was analyzed employing ERT(electrical resistance tomography,a non-intrusive flow visualization technique),and computational fluid dynamics(CFD).The numerical models were validated by comparing the axial solid concentration profiles generated using the ERT data and the CFD simulation *** influences of various important parameters such as the diameter of the inner axial impeller,the inner impeller type,and the inner impeller spacing on the hydrodynamic characteristics of the slurry suspensions in a coaxial mixing vessel were thoroughly *** radial and axial velocity profiles of solid particles were generated using the validated mathematical *** assessment of energy loss due to the solid-solid collisions,the particle-fluid frictions,and the particle-vessel wall collisions was *** evaluation of optimum inner impeller clearance and inner impeller diameter is essential to attain a high degree of solids suspension and dissemination in a coaxial slurry mixing system.

关键词： Coaxial mixer slurry suspension Homogeneity mixing index Electrical resistance tomography(ERT) Computational fluid dynamics(CFD)