• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 202
  • 47
  • 45
  • 16
  • 16
  • 14
  • 9
  • 9
  • 6
  • 3
  • 3
  • 2
  • 2
  • 2
  • 1
  • Tagged with
  • 481
  • 73
  • 70
  • 53
  • 52
  • 35
  • 33
  • 31
  • 28
  • 28
  • 28
  • 28
  • 27
  • 25
  • 24
  • 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.
271

Challenges in the conservation of the Negeri Sembilan Traditional Malay House (NSTMH) and establishment of a conservation principles framework

Sulaiman, Mohd Sabere January 2017 (has links)
The survival of vernacular architecture in the world, and particularly in Negeri Sembilan, Malaysia, is under threat due to rapid modernization, urbanization, socioeconomic transformation, loss of its characteristics resulting from changes and development, and misinterpretation of its typology as well as serious issues of abandonment. Most Negeri Sembilan traditional Malay houses (NSTMH), in some cases over one hundred years old, are unprotected and are becoming derelict. The vernacular value of these houses and their preservation for future generations are therefore threatened. To date, little research has been undertaken into the challenges posed in the conservation of NSTMH from the perspectives of house owners and professionals, and how the changing patterns of their form, fabric, and function have shaped the challenges of preserving them. To explore this from a more holistic approach, existing local heritage legislation that protects traditional Malay houses in particular or timber vernacular architecture in general, and international charters were reviewed, as also successful cases of preservation of similar heritage. This research employs a multi-method qualitative approach by examining as a purposive sample selected 19th-century long-roof-type NSTMHs. The research methods consisted of semi-structured interviews with house owners and conservation experts, on-site survey of the houses’ changing patterns of form, fabric, and function, as well as reviews of the conservation heritage legislation context (national/ local) and international charters. Interview data were analysed using thematic analysis, while the accepted concept model of cultural heritage was used for analysis of the patterns of changes in the cases examined. Documents were reviewed using template analysis. Findings from the research outline the main challenges that include a lack of appreciation and understanding of heritage among house owners, lack of traditional building skills, lack of government support as well as insufficient documentation. Nonetheless, there is no legislation in place at either a national or local level to protect the traditional Malay house. All of the findings were triangulated prior to the development of the initial framework and further expert validation was obtained to establish the final framework. This research makes a significant contribution in expanding the existing body of knowledge, through exploration of how the house owners understand, value, and appreciate heritage within their environment, in addition to including conservation experts’ perspectives in this regard. Moreover, the main contribution of this study is the provision of a Conservation Principles Framework for the NSTMH that may be used by house owners, conservation experts, officials, the Village Security & Development Committee, academics, and students as a form of guidance to the implementation of conservation works. It is also hoped that it may act as a starting point for the Negeri Sembilan state government to develop guidance aimed to safeguard this valuable Malaysian heritage.
272

Petrographic and Kinematic Investigation of the Volcaniclastic and Plutonic Rocks of the Northern Alisitos Arc, Baja California, Mexico

Tutak, Fatin 19 February 2008 (has links)
The Alisitos arc segment forms part of the western zone of Jura-Cretaceous Peninsular Ranges batholith of Baja California. It extends south from the ancestral Agua Blanca Fault to the state boundary between Baja Norte and Sur. The study area is located within a fold and thrust belt intruded by a number of plutons that were emplaced during and after the deformational event. The northern end of the Alisitos arc is characterized by subvertical tight to isoclinal folds and high-angle reverse faults that define a northwest trending, southwest vergent fold and thrust belt. The aABF defines the northern limit to the Alisitos arc segment. In this study we present the results of a petrographic study of igneous rocks in order to determine the relative timing and the distribution of deformation within the northern Alisitos arc segment. The study includes samples of the mylonitic shear zone of the aABF, and plutonic samples from intrusions proximal to the aABF emplaced later during regional deformation. These samples were investigated in order to characterize the distribution of the subsolidus strain in grain scale and the sense of shear during later phases of deformation in the northern Alisitos arc. The results are presented and discussed based on the mineralogical and textural observations from the Balbuena pluton, the Piedra Rodada pluton, and volcaniclastics that were deformed within the aABF. The Balbuena pluton, emplaced at ~ 108 Ma after the surrounding country rocks had already been folded, exhibits little if any evidence for subsolidus deformation. In contrast, the Piedra Rodada pluton, emplaced at ~ 105 Ma just to the southwest of the aABF, exhibits a strong magmatic fabric overprinted by a moderate subsolidus fabric to the southwest that grades into a strong subsolidus fabric with proximity to the fault. Kinematics observed from lineation parallel-foliation normal sections exhibit consistent top-to-the southwest sense of shear.
273

Filamentos elásticos de elastolefina de alta durabilidad obtenidos a partir de copolímeros de bloque de etileno-octeno de baja densidad mediante la tecnología de polimerización por transferencia de cadena para aplicaciones en indumentaria de uso profesional

Verdú Blasco, Pau 29 October 2010 (has links)
En la actualidad el mercado carece de prendas elásticas para uso profesional puesto que los elastanos habitualmente utilizados son inestables frente a altas temperaturas y químicos agresivos, e.g. termofijado, mantenimiento de indumentaria industrial etc. Recientemente se han venido utilizado filamentos olefínicos obtenidos a partir de copolímeros al azar de etileno-octeno (Dow XLA fibers producidos por The Dow Chemical Company). Aunque más resistentes a las temperaturas debido a la reticulación, su bajo punto de fusión, alrededor de 50ºC, limita el comportamiento elástico en tejidos pesados y tupidos para indumentaria profesional. La investigación tiene por objeto la obtención de monofilamentos elásticos a partir copolímeros de bloque de etileno-octeno (cuyo punto de fusión es más elevado) y con éstos, tejidos para indumentaria profesional que ofrezcan mayor fuerza de encogimiento a las temperaturas típicas de los pre-tratamientos, tintura y acabado (50ºC-120ºC). El objetivo es hacer que los tejidos encojan más durante las operaciones en húmedo bajo temperatura para mejorar así su elasticidad y aumentar el peso en comparación con los tejidos actuales manufacturados con los convencionales copolímeros homogéneos de etileno-octeno reticulados Los tejidos deberán garantizar las siguientes propiedades durante todo su ciclo de vida: estabilidad dimensional, relación elasticidad-crecimiento mejorado, resistencia química, resistencia térmica, durabilidad ante los lavados industriales y un mejor confort termofisiológico y sensorial. / Due to the lack of stability of elastane based materials against high temperatures and harsh chemicals, e.g. thermofixation and professional wear maintenance, elastic garments with elastane content are not yet fully commercial products. The Dow Chemical Company has recently commercialized a random ethylene-octene copolymer based fiber named Dow XLA fiber. Despite its higher temperature resistance as one of the crosslinking effects, its very low melting point, around 50ºC, establishes some limitations in elasticity such in heavy weight and high densely woven fabric cases typically found in professional wear applications. The target for the investigation is to produce block ethyleneoctene copolymer based filaments in which the melting point is supposed to be higher than in random copolymer materials. Different workwear fabrics will be manufactured with yarns containing such elastic filaments. It is supposed these fabrics to show high shrinkage forces even at dyeing and finishing temperatures, (50ºC-120ºC). The goal is to produce fabrics with superior shrinkage performance in order to achieve an excellent elastic power and the final desired fabric weight. Properties such as dimensional stability, stretch and growth ratio, temperature and chemical resistance and durability against industrial laundering should not be affected by the passage of the time. To validate this point these properties will be measured in the fabrics off loom and after the garment cycle life. These fabrics are also supposed to show better thermophysiological and sensorial properties than random copolymer fiber based textiles
274

Engineering amphiphilic fabrics for microfluidic applications

Owens, Tracie LeeAnne 14 November 2011 (has links)
Woven textile fabrics were designed and constructed from hydrophilic and hydrophobic spun yarns to give planar substrates containing amphiphilic microchannels with defined orientations and locations. Polypropylene fibers were spun to give hydrophobic yarns, and the hydrophilic yarns were spun from a poly(ethylene terephthalate) copolyester. Water wicking rates into the fabrics were measured by video microscopy and longitudinal wicking tests from single drops and from reservoirs. Intra-yarn microchannels in the hydrophilic polyester yarns were shown to selectively transport aqueous fluids, with the flow path governed by the placement of the hydrophilic yarns in the fabric. Simultaneous wicking of an aqueous and hydrocarbon fluid into the hydrophilic and hydrophobic microchannels of an amphiphilic fabric was successfully demonstrated. The high degree of interfacial contact and micron-scale diffusion lengths of such co-flowing immiscible fluid streams inside amphiphilic fabrics suggest potential applications as highly scalable and affordable microcontactors for industrial liquid-liquid extractions. The efficiency of liquid-liquid extractions carried out with the amphiphilic fabrics was evaluated. Solvent extraction efficiencies were shown to reach up to ~98%.
275

EVOLVING CONTACT NETWORKS TO ANALYZE EPIDEMIC BEHAVIOUR AND STUDYING THE EFFECTS OF VACCINATION

Shiller, Elisabeth 09 January 2013 (has links)
Epidemic models help researchers understand and predict the nature of a potential epidemic. This study analyzes and improves network evolution technology that evolves contact networks so that simulated epidemics on the network mimic a specified epidemic pattern. The evolutionary algorithm incorporates the novel recentering-restarting algorithm, which is adopted into the optimizer to allow for efficient search of the space of networks. It also implements the toggle-delete representation which allows for broader search of solution space. Then, a diffusion character based method is used for analyzing the contact networks. A comparison of simulated epidemics that result from changing patient zero for a single contact network is performed. It is found that the location of patient zero is important for the behaviour of an epidemic. The social fabric representation is invented and then tested for parameter choices. The response to vaccination strategies (including ring vaccination) is then tested by incorporating them into the epidemic simulations. / Ontario Graduate Scholarship (OGS), Natural Sciences and Engineering Research Council of Canada (NSERC)
276

Audinių skersinio pjaustymo įrenginys / Fabric cross cutting machine

Gustas, Karolis 02 July 2012 (has links)
Bakalauriniame darbe konstruojamas gaminys - „Audinių skersinio pjaustymo įrenginys". Nagrinėti šioje srityje naudojami įtaisai ir priemonės, parinkta keletas galimų konstrukcinių variantų, atliktas jų palyginimas (privalumai ir trūkumai). Atlikti šio prietaiso, transporterio techniniai skaičiavimai. Analizuoti du prietaiso detalių pagaminimo technologiniai maršrutai, nustatyti įrenginiai reikalingi atlikti mechanines operacijas. Darbe pateikiami techniniai ir eksploataciniai reikalavimai naudojant įrenginį darbo procese. Ekonominiais skaičiavimais nustatyta ir pagrįsta gaminio savikaina. / All cutting machinery is similar to each other because of their working principle. They all have cutting knife and some kind of shafts which pulls fabric. „Audinių skersinio pjaustymo įrenginys“ is made from laser cut metal and some construction tubes. Other used drives is electric motors, reducers, pneumatic cylinders, belt drives. This device can make all kind of blankets varying from 10 to 60mm thickness, all sort of fabrics, up to 2000 mm width and custom lenght. This paper describes the purpose of a blanket cutting machine, presents its technical specification and carried out analysis of constructional variants, technical calculations, and operational requirements. When designing the blanket cutting machine information from technical library of joint stock company "UAB Dominari" and collected information on peculiarities of maintenance and repairs of technological equipment of the company were used. Additionally, material available from Šiauliai University Technology Faculty library and methodological material from the department were used, scholarly and technical literature was analyzed, patent search was done, internet search engine was used.
277

Structural behaviour and optimization of moment-shaped reinforced concrete beams

Hashemian, Fariborz 25 July 2012 (has links)
This research includes a preliminary study prior to the commencement of the Ph.D. work and three phases of design, construction and testing of three generations of moment-shaped beams. Each phase of the research brought a better understanding of curved beams which follow the shape of the moment diagram. The moment diagram in this study was for simply supported beams supporting a uniformly distributed load as would be the case in the majority of building designs. The original theory for this research can be described as follows: Moment-shaped beams are the natural outcome of a fundamental understanding of stress paths in a horizontal load bearing member. By following these stress paths we may provide materials where required to most efficiently carry the compression and tension stresses to the supports. Allowing stresses to follow their naturally desired paths reduces regions where stresses cross paths called disturbed regions. The outcome of the final phase of this research was the development of the third generation of curved beams with a camber. These beams, designated as Cambered Curve beams (CCBs), exhibited the same behaviour as the rectangular control beam design using CSA-A23.3 up to the serviceability failure of L/360 (12mm). The CCB moment-shaped beams require 20% less concrete and 40% less reinforcing steel (no shear stirrups) to carry the ultimate load which is only 12% less than that carried by the CSA-designed control beam. Due to a closed system of internal forces, the moment-shaped beams remain intact and are able to sustain self weight, even after total failure. A significant part of this research was to modify and verify a FORTRAN-based finite element analysis program: FINIT-Y. This program was reconstructed to analyse a full size beam, and enabled the researcher to model and correctly predict the maximum load, crack pattern and failure mode. This study found that moment-shaped beams with no shear reinforcement have the same stiffness and load carrying capacity as the CSA-designed rectangular control beam with shear reinforcement up to serviceability failure (L/360). The study also found that moment-shaped beams have significantly lower ductility at the ultimate load.
278

Undersökning av koppars effekt som antibakteriellt agens i tyg / Investigation of the efficacy of copper as an antibacterial agent in fabric

Tuvhag, Ellinor January 2014 (has links)
Syftet med denna studie var att undersöka den antibakteriella effekten hos ett polyestertyg med tunna invävda koppartrådar. Frågeställningen som skulle besvaras var ifall koppartyget hade en baktericid eller bakteristatisk effekt. Koppartyget är ännu i prototypstadie och om det visar sig ha antibakteriella egenskaper är det tänkt att användas inom klinisk verksamhet för att förhindra bakterietillväxt i sår och andra känsliga lokaler. Koppar är ett essentiellt spårämne, men har också antimikrobiella egenskaper som utövas genom ett brett spektra av mekanismer där skador på cellmembranet är en av de viktigare. Metoderna som användes för att inokulera bakterier på tyget var absorptionsmetoden, där en näringsbuljong innehållande Staphylococcus aureus ATCC 6538 pipetterades på tygproverna, och transfermetoden där tygproverna trycktes mot en agar som racklats med peptonsaltlösning innehållande S. aureus. Totalantalet viabla bakterier per tygprov beräknades efter kort kontakt (<1min) och inkubering (18-24 h vid 37±2°C) genom att räkna viable count. Resultaten efter inkubering visade signifikant skillnad i totalantal bakterier mellan koppartyget och negativ kontroll i tre av fyra försök. Kort kontakt visade tendens till viss antibakteriell effekt. Slutsatsen är att koppartyget skadade och dödade bakterier då de fick inkubera på tyget, medan fler försök behövs för att säkerställa effekten av kort kontakt med koppartyget. / The purpose of this study was to test the antibacterial effect of thin copper treads woven into a polyester fabric. The investigation was done by inoculation of Staphylococcus aureus strain ATCC 6538 to the fabric and evaluation of the number of viable cells post exposure by viable count. The issue to be answered was whether the copper fabric had a bactericide or bacteriostatic effect? The fabric is still in prototype stage, and if proven to have antibacterial properties the aim is to use it to prevent bacterial growth in wounds and other vulnerable locations in clinical care. Copper is an essential trace element, but also has antimicrobial properties through a wide range of mechanisms where cell membrane damage is one of the more important. Methods used for inoculation was the absorption method, where a nutrient broth containing S. aureus was pipetted on to the fabric specimens, and the transfer method where the fabric specimens were pressed onto an agar plate that had previously been spread with peptone salt solution containing S. aureus. Total number of bacteria per fabric specimen after short contact (<1 min) and incubation (18-24 h at 37±2°C) was calculated. Incubation showed significant difference in total number of bacteria between the copper fabric and negative control in three of four tests. Short contact showed a tendency of antibacterial effect. The conclusion was that the copper fabric harmed and killed bacteria during incubation but that more records would be needed to be sure about the effects of short contact on bacteria.
279

Localization of the source of large silicic ignimbrites through magnetic techniques : applications in Turkey

Agro, Alessandro 14 March 2014 (has links) (PDF)
This research exploits a combination of field, paleomagnetic and rock-magnetic techniques to correlate locate the source and investigate several ignimbrites from two selected regions of Turkey, belonging to two large silicic ignimbrite systems : the well-investigated Cappadocia region (central Anatolia) and the poorly studied Afyon-Eskişehir region (western Anatolia). Investigation of the Upper Miocene Kızılkaya ignimbrite (Cappadocia region) consisted in a stratigraphic rock-magnetic study of the ignimbrite unit, which is considered to be a single flow and cooling unit. Remanent magnetization, magnetic fabric (AMS, AIRM and AARM) and magnetic mineralogy investigations were performed at 35 sites in 7 areal distributed localities at different distance from the vent position inferred by Le Pennec et al. (1998) and different stratigraphic heights, for a total of 444 specimens. Magnetic remanences are not vertically homogenous through the deposits. Two cases are distinguished: (1) a stable TRM, whose direction is consistent with previous literature data (Piper et al., 2002) and (2) two magnetization components with overlapping blocking temperature and coercivity spectra. These situations have been referred respectively to the occurrence of only primary Ti-magnetite, and primary Timagnetite plus secondary magnetic phases (alterated Timagnetite and/or hematite). The AMS fabric varies vertically throughout the deposit; based on the angle between the direction of the magnetic lineation K1 and that of the foliation plunge K3, three types of fabric are evidenced: normal, oblique and transverse. After have attested a primary origin of the magnetic fabric, the AMS was firstly enhanced by discarding all specimens whose density values differ more than +/- 1σ from the site mean value. This resulted in the elimination of the oblique fabrics, which are interpreted as an orientation disturbance due to local occurrence of pumices and lithic clasts in the specimens. Measurement of the AIRM and AARM pointed out that MD Timagnetite is the main carrier of the fabric, which suggests that the magnetic fabric is a reliable proxy for flow directions. Investigation of the Early-Upper Miocene ignimbrite succession exposed in the region of Afyon- Eskişehir consisted in a stratigraphic-sedimentologic and rock-magnetic study of the ignimbrite deposits over a ≈14,300 km2 extended area, in order to locate the source by combining field data and magnetic fabric flow directions. Measurement of the stratigraphic sections, performed at 76 distributed localities, led to ignimbrite correlations and production of isopach and isopleth maps. The ignimbrite succession consists of at least three distinct eruptions that originated the Incik, Sabuncu and Seydiler ignimbrites, different for age, areal distribution, structure and textural features of the deposits. Magnetic investigation consisted in magnetic mineralogy and magnetic fabric analyses (AMS and AIRM), was performed at 22 distributed localities for a total of 36 sites at different stratigraphic heights and 600 specimens. Both field data and magnetic fabric results concur for two source areas. The source area of the Incik and Sabuncu ignimbrites is identified with the Kırka caldera, a ≈20 x 20 km extended area where the presence of a resurgent dome has been detected; source area of the Seydiler ignimbrite is identified in the proximity of the village of Bayat. Volume calculations based on field data pointed out a VEI index of 7 for the Incik and Seydiler ignimbrite, 6 for Sabuncu ignimbrite, evidencing Plinian eruptions; the correspondent magnitude M (Pyle, 2000) is greater than 7 for each ignimbrite.
280

Structural behaviour and optimization of moment-shaped reinforced concrete beams

Hashemian, Fariborz 25 July 2012 (has links)
This research includes a preliminary study prior to the commencement of the Ph.D. work and three phases of design, construction and testing of three generations of moment-shaped beams. Each phase of the research brought a better understanding of curved beams which follow the shape of the moment diagram. The moment diagram in this study was for simply supported beams supporting a uniformly distributed load as would be the case in the majority of building designs. The original theory for this research can be described as follows: Moment-shaped beams are the natural outcome of a fundamental understanding of stress paths in a horizontal load bearing member. By following these stress paths we may provide materials where required to most efficiently carry the compression and tension stresses to the supports. Allowing stresses to follow their naturally desired paths reduces regions where stresses cross paths called disturbed regions. The outcome of the final phase of this research was the development of the third generation of curved beams with a camber. These beams, designated as Cambered Curve beams (CCBs), exhibited the same behaviour as the rectangular control beam design using CSA-A23.3 up to the serviceability failure of L/360 (12mm). The CCB moment-shaped beams require 20% less concrete and 40% less reinforcing steel (no shear stirrups) to carry the ultimate load which is only 12% less than that carried by the CSA-designed control beam. Due to a closed system of internal forces, the moment-shaped beams remain intact and are able to sustain self weight, even after total failure. A significant part of this research was to modify and verify a FORTRAN-based finite element analysis program: FINIT-Y. This program was reconstructed to analyse a full size beam, and enabled the researcher to model and correctly predict the maximum load, crack pattern and failure mode. This study found that moment-shaped beams with no shear reinforcement have the same stiffness and load carrying capacity as the CSA-designed rectangular control beam with shear reinforcement up to serviceability failure (L/360). The study also found that moment-shaped beams have significantly lower ductility at the ultimate load.

Page generated in 0.0302 seconds