The purpose of air distribution systems for HVAC is tocreate proper air quality and thermal conditions in an occupiedzone. In mixing type air distribution systems air is suppliedinto a room through various types of outlets and distributed byturbulent air jets. These air jets are the primary factorsaffecting room air motion. The ASHRAE handbook recognises fourmajor zones of maximum velocity decay along a jet. Although numerous theoretical and experimental studies havebeen conducted to develop turbulent air jet theory from the1930's, air jet performance in the further field from theoutlet is still not well understood. Many studies were therefore carried out, and the followingconclusions can be drawn from them:     The end centerline velocities of zone 3 for both "free"jet and wall jet could strongly depend on the outletvelocities and room size.     TheK-value of wall jets could be a function of bothoutlet velocities and outlet size.     It is very important to choose suitable sampling time toevaluate jet performance.     CFD can not always be used to predict jet behaviour,especially for the jet with low outlet velocity and in thearea far away from the outlet. However, for a two-dimensionwall jet, CFD could be a powerful tool for designers. <b>KEYWORDS</b>: air jet, centerline velocity,K-velocity, air diffuser, ventilation, measurement,CFD

<p>The purpose of air distribution systems for HVAC is tocreate proper air quality and thermal conditions in an occupiedzone. In mixing type air distribution systems air is suppliedinto a room through various types of outlets and distributed byturbulent air jets. These air jets are the primary factorsaffecting room air motion. The ASHRAE handbook recognises fourmajor zones of maximum velocity decay along a jet.</p><p>Although numerous theoretical and experimental studies havebeen conducted to develop turbulent air jet theory from the1930's, air jet performance in the further field from theoutlet is still not well understood.</p><p>Many studies were therefore carried out, and the followingconclusions can be drawn from them:</p><p>    The end centerline velocities of zone 3 for both "free"jet and wall jet could strongly depend on the outletvelocities and room size.</p><p>    The<i>K</i>-value of wall jets could be a function of bothoutlet velocities and outlet size.</p><p>    It is very important to choose suitable sampling time toevaluate jet performance.</p><p>    CFD can not always be used to predict jet behaviour,especially for the jet with low outlet velocity and in thearea far away from the outlet. However, for a two-dimensionwall jet, CFD could be a powerful tool for designers.</p><p><b>KEYWORDS</b>: air jet, centerline velocity,<i>K</i>-velocity, air diffuser, ventilation, measurement,CFD</p>

This thesis reports the results of an experimental study into the flow and heat transfers associated with both inclined and orthogonally impinging axisymmetric air jets. The majority of previously reported studies have been mainly confined to orthogonally impinging jets in stagnant surroundings. In this investigation, free jets as well as the effects of crossflows are considered. This investigation is primarily concerned with local heat transfer variations. The experimental tests were conducted with a single 12.7 mm diameter jet impinging on a flat surface, and heat transfers were evaluated using a heat-mass transfer analogy (the Chilton-Colburn analogy). The sublimation of naphthalene was employed as the mass transfer technique. The flowfield associated with impinging jets has a significant influence on their heat transfer characteristics. In view of the present limited level of understanding of this 'complex' flowfield, extensive flow visualisation techniques were employed in this present investigation. Those were primarily intended to aid interpretation of the experimental heat transfer results, and also to provide further physical understanding of the flowfields resulting from the interactions between impinging jets and crossflowing streams. The flow and heat transfer tests conducted in the programme of work reported in this thesis covered typical ranges of flow parameters of interest in many practical applications of jet impingement systems. Jet inclinations of 45°, 60°, and 90°, nozzle to target spacings of 2, 4, and 8 nozzle diameters were studied. The Reynolds numbers were 30,200, 32,700 and 55,100 and mass velocity ratios in the range 4.0 to 8.8 were studied. The effects of these parameters on the flow and heat transfers associated with impinging jets are reported. Comparisons were drawn between the heat transfer results and those of previously reported studies where appropriate.

The aim of the study is to develop air-textured threads for sewing working clothes with high speed sewing machines; also to study and forecast mechanical and other indicators of sewing threads being produced through the creation of mathematical models that define the association between yarn indicators and technological parameters of production.

No description available.

Curcuminoids have strong anticancer activities but have low bioavailability. The highest rate of cancer deaths comes from lung tumours; therefore, inhaled curcuminoids could treat lung cancer locally. To date, there are no nebulised formulations of curcuminoids, and there are no inhalable curcuminoids particles without excipients using air jet mill and sonocrystallisation methods for DPI formulations. It is the first time; the aerodynamic parameters of curcumin, demethoxycurcumin and bisdemethoxycurcumin were measured individually using NGI. The size, shape, free surface energy, and the crystal polymorphism of the produced inhalable curcuminoid particles were characterised using laser diffraction, SEM, IGC, DSC and XRPD, respectively. Several DPI formulations with a variable particle size of curcuminoids were prepared in two drug-carrier ratios (1:9 and 1:67.5). The best performance of the DPI formulations of the sonocrystallised particles, which exist in crystal structure form1, were obtained from ethanol- heptane, as illustrated FPF 43.4%, 43.6% and 43.4% with MMAD of 3.6µm, 3.5µm and 3.4µm, whereas the best DPI formulation of the air jet milled particles was presented FPF 38.0%, 38.9%, and 39.5% with MMAD of 3.6µm, 3.4µm and 3.2µm for curcumin, demethoxycurcumin and bisdemethoxycurcumin, respectively. Nebulised curcuminoids using nanoemulsion and microsuspension formulations were prepared. The physical properties, such as osmolality, pH and the viscosity of the aerosolised nanoemulsion and the microsuspension formulations were determined. The FPF% and MMAD of nebulised nanoemulsion ranged from 44% to 50% and from 4.5µm to 5.5µm respectively. In contrast, the FPF% of microsuspension ranged from 26% to 40% and the MMAD from 5.8µm to 7.05µm. A HPLC method was developed and validated in order to be used in the determination of curcuminoids from an aqueous solution.

This diploma thesis describes methods of textile fibers treatment, production levels with detailed focus on spinning process especially by Rieter AG in Winterthur, Switzerland, subsidiary company in Usti nad Orlici. Thesis also describes production materials and it’s behavior in relations to production machines. Analysis of the current solution, it’s pros and cons is also done. Setting of requirements of new solution. Creating proposals of design solutions of yarn keeper with mechanic clamp situated on spinning unit on Air-Jet machine. Creating concepts and proposal schemes. After choosing of best possible solution considering production costs, electric consumption during working machine and during active cycle was this variation produce. At the end is review of complete solution and prospective next steps in testing not only in laboratory and prospects of using in field.

No description available.

Woven glass composites have been used for many years in commercial applications due to their light weight, competitive price and good engineering properties. Absorption of energy by laminated composite material results in damage in various forms, the most common of which is delamination. Inter-laminar fracture causes the layers of composite to separate, resulting in a reduction in stiffness and strength of the composite structure, matrix cracking and in some cases fibre breakage takes place. The aim of this project was to improve the inter-laminar bond strength between woven glass fabric and resin. Air jet texturing was selected to provide a small amount of bulk to the glass yarn. The purpose was to provide more surface contact between the fibres and resin and also to increase the adhesion between the neighbouring layers. These were expected to enhance the resistance to delamination in the woven glass composites.Glass yarns were textured by a Stähle air jet texturing machine. Core-and-effect yarn was produced instead of a simple air textured yarn. Hand loom and vacuum bagging techniques were used for making the fabric and composite panels from both textured and non-textured yarns. Density and fibre volume content were established for physical characterisation. Breaking strength (tenacity) of the yarns and tensile, flexure, inter-laminar shear strength (ILSS) and fracture toughness (mode 1) properties of the composites were determined. Projection microscopy and SEM imaging techniques were used to assess the fractured surfaces of the composite specimens. The yarn tenacity and the tensile properties of the composites were significantly reduced after the texturing process, whereas flexure properties were unchanged. However, significant improvement was observed in the ILSS and fracture toughness of the composites after the texturing process. It was also observed that the composites made from the fabrics with textured yarns in only the weft direction are the most advantageous as they maintained the tensile and flexure properties but have significantly higher inter-laminar shear strength.

Les prothèses vasculaires textiles en polyéthylène téréphtalate (PET) présentent souvent des occlusions après implantation pour les petits diamètres (6-8mm) car la surface des prothèses est peu hémocompatible. Or, l'hémocompatibilité des prothèses serait largement améliorée si ces dernières se recouvraient d'une couche de cellules endothéliales qui tapissent naturellement les vaisseaux sanguins. Ce projet vise à mettre en évidence que les textiles bruts ne sont pas un support viable pour le développement de ces cellules endothéliales, puis propose de remplacer les matrices protéiniques par un recouvrement synthétique. Pour ce faire, de l'acide poly-L-lactique (PLA) solubilisé a été filé sous forme de nanofibres déposées sur la surface luminale de la prothèse. L'étirage par jet d'air a été caractérisé selon un modèle plan, puis adapté à la fon11e tubulaire des prothèses. Les nanofibres ont été évaluées sur le plan de la cytocompatibilité, de l'adhérence et de la prolifération avec un modèle de cellules endothéliales animales. Ce travail vise aussi à optimiser l'adhérence de ces fibres sur le PET par l'emploi d'une technique de modification de surface par plasma. Les résultats montrent qu'il est possible de produire des nanofibres de PLA et de contrôler leur diamètre, et de sceller la paroi de la prothèse textile. Enfin, les cellules endothéliales prolifèrent en monocouche sur des prothèses recouve1tes de nanofibres. Il est possible d'optimiser l'adhérence des nanofibres sur le PET avec un traitement par plasma. En conclusion nous avons proposé une alternative à l'enduction traditionnelle des prothèses permettant la prolifération en monocouche des cellules endothéliales. / Textile vascular prostheses show poor patency rate for smaller diameter grafts (6-8mm). Mainly due to thrombosis or hyperplasia, graft failures can be explained by meagre hemocompatibility. Lack of neoendothelialization of the inner wall of the graft can be one reason explaining this poor hemocompatibility, This project aimed to prove that bare textiles are not a good support to stand endothelial cells' proliferation. Poly(L-latic) acid was therefore chosen to replace protein coating by being formed as a nanofibres mesh on the PET textile prostheses luminal surface. Air jet spinning process was first evaluated in a basic planar model to determined optimal parameters for nanofibres production. Endothelial cells compatibility, adhesion and proliferation were tested. Then air jet spinning was dedicated to tubular shape of textile vascular prostheses. Nanofibres mesh were analysed for chemical and physical properties, and covered graft were tested for water permeability. Lastly, atmospheric pressure plasma treatment was performed to optimize PLLA nanofibres adhesion on PET. Results showed that nanofibre diameters were controlled by polymer concentration. Nanofibre cristallinities depend of spinning parameters. Air jet spinning allows quick covering of textile surfaces with a dense net of nanofibre scelling the inner wall of the prosthesis, even in tubular samples. Moreover, endothelial ceIls show monolayer proliferation on these nanofibres. Finally, Polylactic acid adhesion on PET was optimized with atmospheric pressure plasma. In conclusion, we bring a new solution to cover inner wall of prostheses, allowing a monolayer proliferation of endothelial cells.