1,004 research outputs found
MAT-715: SUSTAINABLE HIGH-VOLUME FLY ASH GROUTS FOR TWO-STAGE CONCRETE
Two-stage concrete (TSC) is a special type of concrete in which coarse aggregates are pre-placed in the formwork and subsequently injected with a grout. Beneficiating fly ash in TSC grouts increases TSC sustainability through the ecological use of large quantities of fly ash, reduced carbon-dioxide emissions associated with cement production, and enhancement of resource productivity of the concrete industry. Limited research has explored the effects of using high volume of fly ash as partial replacement for cement in TSC grout mixtures. Therefore, the flowability of grout mixtures incorporating various fly ash addition rates (i.e. 0%, 30%, 50% and 70%) was evaluated using the flow cone method and spread flow test. Correlations between the efflux time and spread flow for the grout mixtures were developed. Results show that increasing the fly ash addition reduced the grouts efflux time while increasing its spread flow. The optimum high-volume fly ash dosage for achieving high flowability and acceptable TSC compressive strength was identified
Multi-Sensor Fusion for Mono and Multi-Vehicle Localization using Bayesian Network
International audienc
MAT-716: GREEN SIDEWALKS USING SUSTAINABLE TWO-STAGE CONCRETE
Two-stage concrete (TSC) is a special type of concrete, which has a high potential for use in sidewalk construction owing to its high volume stability. TSC is characterized by its high coarse aggregate content. Hence, using recycled solid waste materials as a coarse aggregate will increase TSC sustainability, while providing a cost-effective alternative to natural aggregates. Aggregates are pre-placed in TSC. Hence, water absorption by recycled concrete aggregates and the associated rheology problems do not exist in TSC. This study explores the performance of green TSC sidewalks incorporating recycled concrete aggregates (RCA) and crumb rubber from scrap tires. Mechanical properties of the proposed green TSC including compressive strength, modulus of elasticity, flexural strength and toughness, as well as durability to freeze-thaw cycles were investigated. Results show a slight reduction in TSC mechanical properties due to the use of RCA. Moreover, incorporating tire particles reduced TSC mechanical properties significantly, while improving its toughness and freeze-thaw resistance. Addition of recycled tire steel wires allowed to overcome the negative effects on the mechanical properties induced by crumb tire rubber. Therefore, recycling solid waste materials in TSC sidewalks can be an effective strategy to beneficiate such waste materials
Genomic epidemiology of the first epidemic wave of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Palestine.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the novel coronavirus responsible for the COVID-19 pandemic, continues to cause a significant public-health burden and disruption globally. Genomic epidemiology approaches point to most countries in the world having experienced many independent introductions of SARS-CoV-2 during the early stages of the pandemic. However, this situation may change with local lockdown policies and restrictions on travel, leading to the emergence of more geographically structured viral populations and lineages transmitting locally. Here, we report the first SARS-CoV-2 genomes from Palestine sampled from early March 2020, when the first cases were observed, through to August of 2020. SARS-CoV-2 genomes from Palestine fall across the diversity of the global phylogeny, consistent with at least nine independent introductions into the region. We identify one locally predominant lineage in circulation represented by 50 Palestinian SARS-CoV-2, grouping with genomes generated from Israel and the UK. We estimate the age of introduction of this lineage to 05/02/2020 (16/01/2020-19/02/2020), suggesting SARS-CoV-2 was already in circulation in Palestine predating its first detection in Bethlehem in early March. Our work highlights the value of ongoing genomic surveillance and monitoring to reconstruct the epidemiology of COVID-19 at both local and global scales
Recommended from our members
Verification Test Suite (VERTS) For Rail Gun Applications using ALE3D: 2-D Hydrodynamics & Thermal Cases
A verification test suite has been assessed with primary focus on low reynolds number flow of liquid metals. This is representative of the interface between the armature and rail in gun applications. The computational multiphysics framework, ALE3D, is used. The main objective of the current study is to provide guidance and gain confidence in the results obtained with ALE3D. A verification test suite based on 2-D cases is proposed and includes the lid-driven cavity and the Couette flow are investigated. The hydro and thermal fields are assumed to be steady and laminar in nature. Results are compared with analytical solutions and previously published data. Mesh resolution studies are performed along with various models for the equation of state
Dominantes pathologiques chez les caprins du Nord Marocain: cas de la région de Tétouan
Dans le but de caractĂ©riser les dominantes pathologiques des caprins dans la province de Tetouan, un suivi clinique a portĂ© sur 13 Ă©levages caprins de dĂ©cembre 1993 Ă mai 1994. En plus, une Ă©tude lĂ©sionnelle macroscopique et microscopique a Ă©tĂ© rĂ©alisĂ©e sur 400 carcasses de caprins au niveau de 2 abattoirs ruraux. La frĂ©quence de mortalitĂ© moyenne dans les Ă©levages suivis Ă©tait de 22,4% et la mortalitĂ© a touchĂ© plus les chevreaux de moins dâun mois dâĂąge (82,5%). Les frĂ©quences dâavortements variaient de 5,3% Ă 13.3% avec une frĂ©quence moyenne de 7,2% et affectaient beaucoup plus les chĂšvres primipares (60%). Les diarrhĂ©es des chevreaux ont Ă©tĂ© notĂ©es dans 38% des Ă©levages avec une frĂ©quence moyenne de morbiditĂ© de 22,4% et elles Ă©taient responsables de 45% des mortalitĂ©s des chevreaux. La phtiriose a Ă©tĂ© observĂ©e dans 100% des Ă©levages avec une frĂ©quence moyenne de morbiditĂ© de 13%. Les abcĂšs ganglionnaires (lymphadĂ©nite casĂ©euse) ont Ă©tĂ© observĂ©s dans 38% des Ă©levages. Sur les carcasses examinĂ©es Ă lâabattage, les broncho-pneumonies vermineuses Ă©taient les plus frĂ©quentes (49%) suivies des kystes hydatiques pulmonaires et/ou hĂ©patiques (9%), des hĂ©pato-cholangites (7%) et la cysticercose hĂ©pato-pĂ©ritonĂ©ale (6%). Dâautres lĂ©sions comme lâictĂšre, lâadĂ©nomatose et la lymphdĂ©nite casĂ©euse ont Ă©tĂ© relevĂ©es mais avec une frĂ©quence moindre. Au total 160 poumons (80% des organes porteurs de lĂ©sions) et 30 foies (55%) ont Ă©tĂ© saisis totalement contre 41 poumons (20%) et 22 foies (45%) saisis partiellement. Ces rĂ©sultats montrent lâimportance des pertes Ă©conomiques dues aux problĂšmes pathologiques que subit lâĂ©levage caprin de la rĂ©gion de TĂ©touan en lâabsence de toute intervention technique
Between session reliability of heel-to-toe progression measurements in the stance phase of gait
© 2018 Ade et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The objective of the current study was to determine the test-retest reliability of heel-to-toe progression measures in the stance phase of gait using intraclass correlation coefficient (ICC) analysis. It has been proposed that heel-to-toe progression could be used as a functional measure of ankle muscle contracture/weakness in clinical populations. This was the first study to investigate the test-retest reliability of this measure. Eighteen healthy subjects walked over the GAITRiteÂź mat three times at a comfortable speed on two sessions (â„ 48 hours apart). The reliability of the heel-to-toe progression measures; heel-contact time, mid-stance time and propulsive time were assessed. Also assessed were basic temporal-spatial parameters; velocity, cadence, stride length, step length, stride width, single and double leg support time. Reliability was determined using the ICC(3,1) model and, fixed and proportional biases, and measures of variability were assessed. Basic gait temporal-spatial parameters were not different between sessions (p > 0.05) and had excellent reliability (ICC(3,1) range: 0.871â0.953) indicating that subjects walked similarly between sessions. Measurement of heel-to-toe progression variables were not different between sessions (p > 0.05) and had excellent reliability (ICC(3,1) range: 0.845â0.926). However, these were less precise and more variable than the measurement of standard temporal-spatial gait variables. As the current study was performed on healthy populations, it represents the âbest caseâ scenario. The increased variability and reduced precision of heel-to-toe progression measurements should be considered if being used in clinical populations
Hyperspectral imaging of the microscale distribution and dynamics of microphytobenthos in intertidal sediments
We describe a novel, field-deployable hyperspectral imaging system, called Hypersub, that allows noninvasive in situ mapping of the microphytobenthos (MPB) biomass distribution with a high spatial (sub-millimeter) and temporal (minutes) resolution over areas of 1 x 1 m. The biomass is derived from a log-transformed and near-infrared corrected reflectance hyperspectral index, which exhibits a linear relationship (R-2 > 0.97) with the chlorophyll a (Ch1 a) concentration in the euphotic zone of the sediment and depends on the sediment grain size. Deployments of the system revealed that due to factors such as sediment topography, bioturbation, and grazing, the distribution of MPB in intertidal sediments is remarkably heterogeneous, with Ch1 a concentrations varying laterally by up to 400% of the average value over a distance of 1 cm. Furthermore, due to tidal cycling and diel light variability, MPB concentrations in the top 1 mm of sediments are very dynamic, changing by 40-80% over a few hours due to vertical migration. We argue that the high-resolution hyperspectral imaging method overcomes the inadequate resolution of traditional methods based on sedimentary Ch1 a extraction, and thus helps improve our understanding of the processes that control benthic primary production in coastal sediments
Late capsular bag contraction and intraocular lens subluxation in retinitis pigmentosa: a case report
<p>Abstract</p> <p>Introduction</p> <p>Retinitis pigmentosa is clinically characterized by loss of predominantly rod photoreceptor function as well as loss of peripheral vision. The classic clinical triad is considered to be the presence of bone spicule pigmentation in the peripheral retina, arteriolar attenuation, and waxy disc pallor. Cataracts, most commonly of the posterior subcapsular type, are often found in all forms of retinitis pigmentosa. Ectopia lentis and lens dislocation are known risk factors for those with retinitis pigmentosa, presumably secondary to zonular fiber weakness and vitreous degeneration. The post-operative complication of lens dislocation following cataract extraction in patients with retinitis pigmentosa has also been documented.</p> <p>Case presentation</p> <p>We report a case of severe capsular bag contraction with intraocular lens subluxation following cataract extraction in a 58-year-old Hispanic woman with retinitis pigmentosa.</p> <p>Conclusion</p> <p>Patients with retinitis pigmentosa undergoing cataract surgery should be notified of this potentially late complication of surgery.</p
Impact of circulation on export production, dissolved organic matter and dissolved oxygen in the ocean: Results from OCMIP-2
- âŠ