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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Pullout test of rock bolts at the Lima Hydropower station : -Assessment of the test method

Ljungberg, Jakob January 2016 (has links)
During construction of dams, rock bolts are in general installed in the interface between concrete and rock as an extra safety measure against overturning failure. These bolts are however not allowed to be taken into consideration for the stability calculations of large dams. New standards and new design criterias have increased the requirements of the safety of the old dams, leading to a need for expensive rehabilitation and strengthening. It is possible that consideration of these bolts in stability calculations may lead to money being saved. In order to do so more information about the long term strength of these bolts is needed. One way of getting this information has been the destructive testing of old dugout bolts found during reconstruction works. At the Lima hydropower station in Sweden, this kind of testing was made. The test rig used had a design where a piston pressed down on the rock around the bolt in order to pull it out. The question was raised if this could affect the failure load of the bolt. In this thesis, an attempt was made to answer this question using finite element methods. Models of a rock bolt was made in Abaqus, where one model included the piston and one where it was not. The connection between the bolt and the rock was modelled with nonlinear springs and friction, and the results were then compared between the cases and with experimental data. The results showed that the resulting force-deformation curves may be affected by the piston in cases where the dominant failure mode was adhesive failure, which would influence failure loads and deformations. Since so little was known about the properties of the rock and grout at Lima however, it is difficult to say to which extent the test rig has affected these results.
102

Hydrabolt and Split Set Rock Bolt Selection Method Under the Bieniawski Rock Mass Rating for Improving Horizontal Access Support in Peruvian Mid-Scale Mining Activities

Toscano-Alor, Carlos, Castillo-Rodil, Antoni, Pehovaz-Alvarez, Humberto, Raymundo, Carlos, Mamani-Macedo, Nestor, Moguerza, Javier M. 01 January 2020 (has links)
El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / This paper illustrates how the Bieniawski rock mass rating geomechanics classification, within the support system used by medium-scale mining companies, allows for the development of a new anchor rock bolt selection method aimed at improving horizontal access stability in underground mines. However, this case study only seeks to select the most efficient anchor rock bolt for any given horizontal access. A proper support selection method is very important for mining companies because this decision will safeguard both miners and mining infrastructure. This selection process will ultimately prevent fatal accidents, which is critical for mining companies today, especially considering the constant operation standstills reported in Peru.
103

Text to Image Synthesis via Mask Anchor Points and Aesthetic Assessment

Baraheem, Samah Saeed 15 June 2020 (has links)
No description available.
104

The Epidermal Growth Factor Receptor (EGFR) Is Proteolytically Modified by the Matriptase-Prostasin Serine Protease Cascade in Cultured Epithelial Cells

Chen, Mengqian, Chen, Li Mei, Lin, Chen Yong, Chai, Karl X. 01 May 2008 (has links)
Prostasin is expressed at the apical surface of normal epithelial cells and suppresses in vitro invasion of cancer cells. Prostasin re-expression in the PC-3 prostate carcinoma cells down-regulated the epidermal growth factor receptor (EGFR) protein expression and EGF-induced phosphorylation of the extracellular signal-regulated kinases (Erk1/2). We report here that prostasin and its activating enzyme matriptase are capable of inducing proteolytic cleavages in the EGFR extracellular domain (ECD) when co-expressed in the FT-293 cells, generating two amino-terminally truncated fragments EGFR135 and EGFR110, at 135 and 110 kDa. Prostasin's role in EGFR cleavage is dependent on the serine active-site but not the GPI-anchor. The modifications of EGFR were confirmed to be on the primary structure by deglycosylation. EGFR135 and EGFR110 are not responsive to EGF stimulation, indicating loss of the ligand-binding domains. EGFR110 is constitutively phosphorylated and in its presence Erk1/2 phosphorylation is increased in the absence of EGF. The protease-induced EGFR cleavages are not dependent on EGFR phosphorylation. The EGFR ECD proteolytic modification by matriptase-prostasin is also observed in the BEAS-2B normal lung epithelial cells, the BPH-1 benign prostate hyperplasia and the MDA-MB-231 breast cancer cell lines; and represents a novel mechanism for epithelial cells to modulate EGF-EGFR signaling.
105

Analysis of Anchors and Bracing Configurations for Personal Fall Arrest Systems in Residential Construction

Morris, Justin Collins 20 June 2013 (has links)
Falls continue to be a major problem in the residential construction industry and account for a large number of injuries and fatalities each year (US Department of Labor, 2012).  The effects of a fall are catastrophic to the workers and their families as well as the construction company and surrounding community.  Prevention of these incidents has been the primary focus of organizations such as the Occupational Safety and Health Administration (OSHA).  To reduce the number of falls on residential construction sites, OSHA has put forth several standards that require the use of fall protection.  Although guidelines have been provided, there have been concerns and complaints regarding the standards as well as methods and materials that should be used. The goal of this research was to measure the behavior of a five truss roof system with various anchor points and bracing configurations loaded by a horizontal force.  A lab built roof system was used to test three different anchor types with three forms of temporary bracing.  The materials and methodology used in this testing were based on common materials and practices currently used in the residential construction industry. The results of this research show that anchors must engage multiple trusses to spread the applied load throughout the roof system.  Several forms of temporary bracing such as lateral, diagonal, and sway bracing, are also required to strengthen the roof system allowing it to withstand an applied load. / Master of Science
106

Ankarskenor i byggandet

Alkrdi, Bashar, Lindberg, Jonas January 2020 (has links)
Vårt examenarbete om ankarskenor i byggandet omfattar implementering av en ny teknik i byggandet i form av föringjutna ankarskenor för installationer av VS rör, ventilation, sprinkler och EL. I en allt mer globaliserad värld råder en allt högre konkurrensutsatt marknad, vilket gör att det också ställs högre krav på entreprenörerna inom byggsektorn. Att man inom produktionen ägnar sig åt aktiviteter som inte tillfört något värde till slutprodukten klassas som slöseri. Konsten att effektivisera sina arbetsmetoder för att därmed uppnå en mer effektiv produktion, samt minska rådande slöseri anses inte vara en enkel uppgift inom byggindustrin. Byggindustrin har uppfattningen om att branschen är unik i sitt slag då förutsättningarna ständigt förändras. En betydande del av detta slöseri är aktiviteter knutna till internhanteringen av material. Slöseriet kan visa sig i form av väntan, materialspill, skador och produktionsstörningar.Byggbranschen anmäler fler arbetsolyckor med sjukfrånvaro än genomsnittet för samtliga branscher. Byggbranschen har i jämförelse med många andra branscher även en betydligt mer fysiskt påfrestande arbetsmiljö. Det handlar då bland annat om tunga lyft, buller och vibrationer. Alla de intervjuade var eniga om att de besparingar som görs med ankarskenor i förhållande till traditionell montering är att momenten borrning och montering av skruvankare eller slagankare försvinner. Analysen visar att tiden för montering har reducerats för alla yrkesgrupper förutom EL. Det visar sig att sprinkler har mest att vinna på monteringen av ankarskena, då de får en reducering på 66% av tiden för montering. VS och ventilation får en minskning på 50% vardera för tidsåtgången vid montering. En våning på vårdbyggnad BY 35 i norra sjukhusområdet är 3480m2. De tidsmässiga besparingarna med ankarskenor är 45,41h per våning. Vilket ger en total tidsmässig besparing för installationerna med ankarskenorna på 0,013 h/m2. Arbetsmomenten för en montering och utmätning på ett Peri skydeck normalvalv på 2200m2 med skenor tar cirka 30 timmar att utföra. I tillägg kommer sedan en rengöring av skenorna där gummiskyddet ska plockas ut och betongrester tas bort maskinellt med en mejselhammare. Den processen tar armerarna cirka 50 timmar att utföra, vilket ger en tidsåtgång för utsättning och rengöring på 0,036h/m2. Utsättningen äter därför upp besparingarna som görs med ankarskenorna i förhållande till traditionell montering.Alla nya metoder har sina utmaningar när de implementeras på arbetsplatsen Även ankarskenorna har detaljer som behöver förbättras enligt brukarna. Arbetare som använder dem eller är involverade har följande förslag på hur ankarskenorna kan förbättras med hänsyn till tid och arbetsmiljö. På de stråken där det hänger mycket rör bör avstånden och placering ses över. Projektörerna måste vara uppmärksamma på vad där ligger. Skenorna skulle varit lika höga som distanserna för armeringen. Då skulle de kunna användas som distanser för att få ett bättre tryck när armeringen pressar ner skenan på armeringen. Skenorna spikas på plats vilket kan ses som en nackdel. Skenorna hade suttit bättre om de hade skruvats på plats. Momentet som inte har tittats på är när det väl är gjutet ska skumgummilisten som sitter i tas bort. Man bör finna ett smidigare sätt att göra det på. När den dras kommer mycket betongvatten. Ett tunt betongskikt på en millimeter som spjälkas loss när den dras bort leder till att det kommer mycket smuts på golvet eller armeraren som drar bort det. Man borde använda sig av heltäckande skyddsglasögonen av typen goggles, vilket skulle reducera risken för damm och partiklar i ögat vid borrning och rengöring av ankarskena.Noggrannheten och precisionen av hur ”korrekta” tiderna som uppgetts är kan ifrågasättas även om det är projektledare och ledande montörer med flera års erfarenhet som kalkylerat tiderna. Det bör tänkas att det vid upphandling oftast är entreprenörer som ger det lägsta priset som vinner. En sådan upphandling leder till att det är en låg vinstmarginal. Det finns således ett vinstintresse för projektledarna och ledande montörer när de kalkylerar tiderna för montering. Slutsatsen är att tiden för ankarskenorna blir längre än för den traditionella tiden för montering. Det är utsättning och rengöring som bidrar till att det blir en tidsförlust i förhållande till traditionell montering. De tidsmässiga vinsterna i form av mindre städning och hämtning av material kan inte mätas och jämföras per m2. De vinster som ankarskenorna bidrar med tidsmässigt är av mer teoretiskt slag om hur arbetsmomenten kan förändras vid montering. Arbetsmiljön för montörerna förändras och förbättras i form att risken för arbetsskador minimeras eller elimineras. För montörerna försvinner de tunga lyften de måste utföra under borrningen när ankarskenan inte kan användas. Buller, vibrationer, flygande partiklar och kvartsdamm elimineras helt med ankarskenan. För armerarna blir arbetsmiljön sämre då de måste rengöra ankarskenan efter gjutning, risker som rengöringen medför är att arbeta med tunga maskiner som ger buller och vibrationsskador. / Our thesis on anchor rails in construction comprises the implementation of a new technology in construction in terms of precast anchor rails for the installation of VS pipes, ventilation, sprinkler, and electrical equipment. The purpose of the study is to critically evaluate the differences between the traditional installations of VS pipes, ventilation, sprinklers, and electricity in relation to installations with precast anchor rails. Our methods include literature studies, semi-structured interviews, and observations. Our study is a field case study that comprises the implementation of anchor rails in the construction project for the two new care buildings in Malmö hospital area for Region Skåne. The result is based on interviews from fitters of the installations, senior installers and project managers.The analysis shows that sprinklers reduces its time by 66%, pipefitters and ventilation by 50% by eliminating the drilling when installing. The time saved with mounted anchor rails is 45,41hrs per floor which gives a time saving, for installations with anchor rails, of 0,036h/m2. The work activities to mount, measure and clean on a 2200m2 Peri skydeck normal vault with rails, take about 80 hours to carry out. The time spent on placement and cleaning is 0,036m2.The accuracy and precision as to how “correct” the times stated are can be questioned even if they have been calculated by project managers and senior installers with years of experience.The conclusion is that the amount of time required to mount anchor rails is greater than that for traditional mounting. It is placement and cleaning that contribute to a time loss in relation to traditional mounting. The installers’ working environment changes or improves as the risk for work related injuries is minimized or eliminated. Noise, vibrations, flying particles and quartz dust is eliminated when using the anchor rail. For concrete workers, the working environment becomes worse when they must clean the anchor rail after molding as the risks include working with heavy machinery that can cause noise and vibration damage.
107

WE ARE HERE: THE SOCIAL IMPACT OF DREXEL UNIVERSITY’S EXPANSION ON MANTUA AND POWELTON VILLAGE

Daniels, Kwesi, 0000-0003-2675-7207 January 2020 (has links)
Drexel University, a private university in Philadelphia, is expanding its campus to attract more students, faculty, and researchers. The current President, John Fry, envisions transforming West Philadelphia into an innovation district. The university is working with real estate developers on a $3.5 billion real estate project at Schuylkill Yards, in addition to mixed-use student housing and projects. The development goals of the university will impact the social conditions of the long-term residents of the two neighboring communities, Mantua and Powelton Village. In addition to the larger developers who are working with Drexel, numerous small-scale developers are developing market-rate student housing around the periphery of the two communities. In the process, the developers are disrupting the character of the neighborhoods and changing the racial demographics of the Mantua community from a predominantly African American community into one that reflects predominantly White and Asian demographics of the university. The combination of Drexel University and the developers is threatening to “studentify” the Mantua community. In the process Mantua, is at risk of losing the cultural elements that have defined the neighborhood for decades, in addition to their sense of belonging in the neighborhoods where the residents have lived for generations. This research is a qualitative assessment of the social changes to the two communities as a result of Drexel’s expansion activities. A social sustainability framework was developed based on the results of a cultural landscape assessment and structured and semistructured interviews of long-term residents, business owners, community leaders, and university officials. / Geography
108

Rapidly Deployable Armoring System for Temporary Protection of Earthen Levees during Overtopping

Bilberry, Amanda Cheree 11 August 2012 (has links)
The objective of this thesis was to develop guidance for an anchored geotextile Rapidly Deployable Armoring System for the landward side of earthen levees to mitigate the effects of storm surge and overtopping waves. A case study of the Backwater Levee protection placed during the 2011 Mississippi River flood by the US Army Corps of Engineers was performed to prove construction feasibility. Full scale anchor testing was performed for 0.3 and 0.6 m rod shaped anchors to determine their load deflection behavior. Anchor test data and shear stress profiles based on flume testing presented in literature were used in conjunction with surface to surface contact interactions to develop a single-layer elastic membrane finite element model (SLEMM) of an RDAS to provide design guidance. The SLEMM appears to perform the finite element formulations correctly, but does not produce physically meaningful results. Further improvements to the model are needed for useable design.
109

Anchorage of Carbon Fiber Reinforced Polymers to Reinforced Concrete in Shear Applications

Niemitz, Carl W 01 January 2008 (has links) (PDF)
Within the past few decades a new technology has emerged using Fiber Reinforced Polymers (FRP) to rehabilitate and retrofit reinforced concrete (RC) structures. In FRP shear strengthening applications it is largely recognized that debonding is the prevailing failure mode. FRP debonding typically occurs prematurely as a brittle failure mode that limits the efficiency of the strengthening technique. No systematic tests have been conducted to investigate the capacity gained by anchoring FRP laminates to RC elements in shear applications. The objective of this research program was to study the effects of anchoring FRP laminates to RC members with FRP anchors thereby delaying or potentially eliminating debonding of FRP sheets from the concrete surface. FRP anchors used in this research were made from fibers used as part of FRP sheets that get bundled into a roll with a fanned upper end of the anchor allowing the fibers to be splayed over the FRP sheet. A single shear pull test experiment was developed to study the effects of anchoring FRP laminates using FRP anchors with varying anchor diameters, lengths, and patterning. The results of the experimental portion of this research project were used in combination with finite element analyses to develop models for anchored FRP sheets that can be used in design of shear strengthening applications.
110

Development of Anchorage System for Frp Strengthening Applications Using Integrated Frp Composite Anchors

Mcguirk, Geoffrey N 01 January 2011 (has links) (PDF)
Over the past three decades the use of externally bonded fiber reinforced polymer (FRP) materials for structural strengthening applications has become an accepted and widely used method. A primary concern of FRP structural strengthening systems is that the FRP often debonds from the concrete well before the load capacity of the FRP material is reached. In addition, debonding failures are often brittle and occur with little warning. Past research concluded that fastening FRP sheets with FRP anchors is an effective method for delaying or preventing debonding failures. However, there is a clear lack of research pertaining to fastening FRP sheets with FRP anchors, and a corresponding lack of design guidance. The primary objective of this research program was to better understand the behavior of bonded FRP sheets that are secured with FRP anchors to aid in future development of design recommendations of this anchorage system. This thesis deals with carbon fiber unidirectional sheets applied using the wet layup system. Design parameters that were investigated include: manufacturer of the FRP materials, unanchored and anchored sheets, number of anchor rows and spacing between rows, number of sheet plies (single or double), and length of bonded sheet behind the anchors. A total of sixteen specimens were tested. Experimental results show that FRP anchorage systems are very effective in increasing load capacity by delaying debonding. Finite element models were also developed of anchored and unanchored bonded FRP sheets.

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