A study of the bending stresses in a pair of meshed spur gears using the finite element method is presented. The models analyzed were in the shape of a circular gear with five teeth or a five-tooth rack. A unit torque (1 lbf-ft) was applied as the form of nodal forces on the nodes around the bore hole of the driver pinion. The nodes around the bore hole of the driven gear (or the nodes along the back of the driven rack) were fixed. In order to transmit the power from the driver pinion to the driven gear (or rack), the points in contact were made coincident. Seven model groups with same diametral pitch (1.0), addendum (1.0 in.), dedendum (1.3 in.), pressure angle (20°) and hob tip radius (0.35 in.) but with varying numbers of teeth on the pinion and gear were analyzed to compute the tensile stress variation in the root fillet during the duration of contact. A model for predicting the tensile stress variation at the root fillet during the duration of contact has been created. The results were compared with AGMA and other results with agreement for the peak within 3%. / M.S.

The main objective of this research project was to study the growth and development of the floral nectar spur of Centranthus ruber (L.) DC. Nectar spurs are tubular floral outgrowths, generally derived from the perianth organs, which typically contain secreted floral nectar. The morphological characteristics of the spur, particularly the length, determine which floral visitors will be able to access the nectar reward pooled at the spur tip. Therefore, nectar spurs are ecologically important for the development of specialised pollinator interactions and have been demonstrated to act as key innovations in the evolution of some taxa. Morphological and anatomical characteristics of the spur and floral nectary were investigated using light and scanning electron microscopy. Ultrastructural features of the nectar spur, particularly the floral nectary within, were assessed using transmission electron microscopy. Nectar in C. ruber is produced by a trichomatous nectary which runs along the entire, inner abaxial surface of the spur. The nectary is aligned with the single vascular bundle which runs along the abaxial side of the spur, through the sub-nectary parenchyma, and back up the adaxial side. The secretory trichomes are unicellular and, in late development, they develop a thick layer of secondary wall ingrowths which vastly increases the surface area of the plasma membrane for nectar secretion. Elongate, non-secretory trichomes occupy the entire remaining circumference of the spur’s inner epidermis, but their density is reduced compared to the secretory trichomes. The cellular basis for spur growth is poorly characterized in the literature. Until recently, it was assumed that all nectar spurs grow by the constant production of new cells via up to three potential meristematic regions (the meristem hypothesis, Tepfer 1953). The cellular basis for spur growth in C. ruber was investigated by cell file counts and cell length and width measurements along the lateral side of nectar spurs in each of the developmental stages. DAPI stained spurs were also examined with Confocal/Apotome microscopy to determine the timing and position of cell division activity throughout spur development. It was determined that elongation of the spur epidermal cells contributes much more to spur growth than cell division. In early development, division is the primary driver of spur growth and the cells are isotropic. However, as development progresses, cell division activity slows down and the spur cells become increasingly anisotropic until anthesis. The patterns of nectar secretion were determined by assessing the volume, solute concentration and carbohydrate composition of the nectar throughout flowering phenology in two C. ruber plants. Nectar volumes and solute amounts rose initially, followed by an eventual decline in both as phenology progressed towards senescence. Because this study was conducted on greenhouse grown plants, it can be assumed that nectar was not removed by insects, suggesting that it is likely reabsorbed following secretion. High performance liquid chromatography (HPLC) analysis determined that C. ruber's nectar is sucrose dominant and that nectar composition remains stable following anthesis throughout floral phenology.

The intensive research on sediment transport indicates a need of an appropriate equation for predicting the total sediment load in rivers to manage reservoirs, operate dam and design in-stream hydraulic structures. None of the available equations in sediment transport has gained universal acceptance for predicting the total sediment transport rate. These facts indicate the need of a general formula to represent all these formula for predicting the sediment transport rate. The first goal of this dissertation is to find a unified total sediment transport equation for all rivers. On the other hand, scour around hydraulic structures such as spur dikes and bridge piers can be a serious problem that weakens structural stability. An investigation on the turbulent flow field and turbulence distribution around such hydraulic structures is essential to understand the mechanism of local scour and to determine which turbulence properties affect the local sediment transport. In addition, a universal turbulent model that is valid for all cases of turbulent flow in open channels does not exist. This dissertation thoroughly examined the turbulent flow field and turbulence distribution around a series of three dikes. The goal is to determine the significant turbulent properties for predicting the local sediment transport rate and to identify the appropriate turbulence model for simulating turbulent flow field around the dikes.To develop a general unified total load equation, this study evaluates 31 commonly used formulae for predicting the total sediment load. This study attributes the deviations of calculated results from different formulae to the stochastic properties of bed shear stresses and assumes that the bed shear stress satisfies the log- normal distribution. At any given bed shear stress, Monte Carlo simulation is applied to each equation, and a set of bed shear stresses are randomly generated. Total sediment load generated from each Monte Carlo realization of all the equations are assembled to represent the samples of total sediment load predicted from all the equations. The statistical properties of the resultant total sediment loads (e.g. standard deviation, mean) at each given bed shear stress are calculated. Then, a unified total sediment load equation is obtained based on the mean value from all the equations. The results showed the mean of all the equations is a power function of dimensionless bed shear stress. Reasonable agreements with measurements demonstrate that the unified equation is more accurate than any individual equation for predicting the total sediment load.An experimental study and numerical simulation of the flow field and local scour around a series of spur dikes is performed in a fixed flat bed and scoured bed condition. A micro-Acoustic Doppler Velocimeter (ADV) is used to measure the instantaneous velocity field in all the three spatial directions and the measured velocity profiles are used to calculate the turbulence properties. Results show that the local scour develops around the first dike. Turbulence intensity together with the mean velocity in the vertical direction measured at the flat bed closely correlates to the scour depth. In addition, the maximum bed shear stress, occurring at the tip of the second dike in the three-dike series, does not correspond to the maximum scour. Large bed load transport due to bed shear stress may not initiate bed scouring, but turbulence bursts (e.g. sweeps and ejections) will entrain sediment from bed surface and develop the local scour.A three-dimensional numerical model FLOW-3D is used to simulate the turbulent flow field around a series of spur dikes in flat and scoured bed. This study examines Prandtl's mixing length model, one equation model, standard two-equation model, Renormalization-Group (RNG) model, and Large Eddy Simulations (LES) turbulence model. The Prandtl's mixing length model and one equation model are not applicable to flow field around dikes. Results of mean flow field by using the standard two-equation model, and RNG turbulence model are close to the experimental data, however the simulated turbulence properties from different turbulent model deviate considerably. The calculated results from different turbulence models show that the RNG model best predicts the mean flow field for this series of spur dikes. None of the turbulence closure models can predict accurate results of turbulence properties, such as turbulence kinetic energy. Based on those results, this study recommends the use of RNG model for simulating mean flow field around dikes. Further improvements of FLOW-3D model is needed for predicting turbulence properties near this series of spur dikes under various flow conditions.

Author: Bc. Kateřina Průchová Title: The effectiveness of shock wave therapy for plantar fasciitis Objectives: The main goal of this work is to assess the effect of the radial and focused shock wave therapy for plantar fasciitis compared with therapeutic ultrasound. Methods: The study included 55 patients with diagnose of heel spur syndrome. Patients were divided into three groups according to undergoing therapy. Group A (n = 20) received 6 applications of radial shock wave, group B (n = 20) obtained 3 applications of focused shock wave and group C received 8 applications of therapeutic ultrasound. Intensity and character of the pain were assessed before and after therapeutic intervention using non-standardized questionnaire. For the assessment and description of the results were used standard statistical indicators and methods. Results: Radial and focused shockwave therapy had according to the obtained results in the selected treatment protocol positive effect on the clinical course of the disease and was markedly more effective than therapeutic ultrasound. Almost all parameters reached the highest percentage improvement in the group treated with 6 applications of radial shock waves. There were no complications and side effects during the experiment. Keywords: heel spur, plantar fasciitis,...

Die Dissertation beschreibt die Entwicklung eines Triggers fuer den Backward Silicon Tracker (BST). Der Detektor wurde im Jahre 2001 installiert und nach der Modifizierung von HERA zur Erreichung hoeherer Luminositaet in Betrieb genommen. Der Backward Silicon Tracker des H1-Experiments wird in Verbindung mit einem Blei-Scintillationsfaser Kalorimeter zur detaillierten Untersuchung der inklusiven tief inelastischen Streuung von Leptonen an Protonen, und der Charm-Erzeugung bei kleinen Werte der Bjorken Variable x eingesetzt. Die guten Eigenschaften von Festkoerper-Halbleitern, geringes elektronisches Rauschen und schnelle Signalantworten, wurden bei der Entwicklung des Silizium Pad-Detektors zum Nachweis von Spuren in der Rueckwaertsregion des H1-Experiments in der ersten Stufe des Triggersystems ausgenutzt. Der neue Triggerdetektor des BST, der Pad-Detektor und die dafuer entwickelte Ausleseelektronik wie auch die implementierte Logik werden beschrieben. Resultate von Teststrahlmessungen und von ersten Messungen unter Luminositaetsbedingungen an HERA-II werden dargestellt. / The Backward Silicon Tracker of the H1 experiment is being used in conjunction with a lead-fiber Calorimeter for detailed investigations of inclusive deeply inelastic scattering of leptons from protons, and of charm production at small values of the Bjorken variable x. In this thesis the development of a trigger for the Backward Silicon Tracker is described. The detector was installed in 2001 and started to operate in H1 after the HERA upgrade. Exploiting the low noise performance and fast time response of solid state semiconductors, a silicon pad detector telescope was developed for the first level trigger on tracks scattered in the backward region of the H1 detector. The design of the new trigger part of the BST consisting of silicon pad detectors and dedicated fast readout circuitry is described. Results of beam tests and first luminosity data are presented.

A spur dike is a hydraulic structure built on the bank of a river at some angle to the main flow direction. A series of spur dikes in a row may also be placed on one side or both sides of a river to form a spur dike field. Spur dikes are used for two main purposes, namely river training and bank protection. For river training, spur dikes may be used to provide a desirable path for navigation purposes or to direct the flow to a desirable point such as a water intake. For bank protection, spur dikes may be used to deflect flow away from a riverbank and thus protect it from erosion. It has also been observed that spur dikes provide a desirable environment for aquatic habitat. Despite the fact that spur dikes are useful hydraulic structures, they have been found to increase the flow resistance in rivers and hence increase the flow stage. The present study focuses on the quantification of the flow resistance and associated flow stage increase due to a single spur dike and also that of a spur dike field. Increased flow stage is referred to herein as a backwater effect.<p> In the first stage of the study, the flow resistance due to a single spur dike, expressed as a drag force exerted on the flow in an open channel, was studied and quantified. The work was carried out in a rigid bed flume, with the model spur dike being simulated using various sizes of a two-dimensional (2-D) rectangular plate. Several discharge conditions were studied. The drag force exerted by the spur dike for both submerged and unsubmerged flow conditions was determined directly from measurements made using a specially designed apparatus and also by application of the momentum equation to a control volume that included the spur dike. It was found that the unit drag force (i.e., drag force per unit area of dike) of an unsubmerged spur dike increases more rapidly with an increase in the discharge when compared with that of a submerged spur dike. The results also showed that an increase in the blockage of the open channel cross-section due to the spur dike is the main parameter responsible for an increase in the spur dike drag coefficient, hence the associated flow resistance and backwater effect. Based on these findings, relationships were developed for estimating the backwater effect due to a single spur dike in an open channel.<p> In the second stage of the study, the flow resistance due to a spur dike field expressed as a drag force exerted on the flow was quantified and subsequently related to the backwater effect. The work was carried out in a rigid bed flume, with the model spur dikes simulated using 2-D, rectangular plates placed along one side of the flume. For various discharges, the drag force of each individual spur dike in the spur dike field was measured directly using a specially-designed apparatus. For these tests, both submerged and unsubmerged conditions were evaluated along with various numbers of spur dikes and various relative spacings between the spur dikes throughout the field. It was concluded that the configuration of a spur dike field in terms of the number of spur dikes and relative spacing between the spur dikes has a substantial impact on the drag force and hence the flow resistance and backwater effect of a spur dike field. The most upstream spur dike had the highest drag force amongst the spur dikes in the field, and it acted as a shield to decrease the drag force exerted by the downstream spur dikes. From the experiments on the submerged spur dikes, it was observed that the jet flow over the spur dikes has an important effect on the flow structure and hence the flow resistance.<p> In the third stage of the study, the flow field within the vicinity of a single submerged spur dike was modeled using the three-dimensional (3-D) computational fluid dynamic (CFD) software FLUENT. Application of the software required solution of the 3-D Reynolds-averaged Navier-Stokes equations wherein the Reynolds stresses were resolved using the RNG ê-å turbulence model. One discharge condition was evaluated in a smooth, rectangular channel for two conditions, including uniform flow conditions without the spur dike in place and one with the spur dike in place. The CFD model was evaluated based on some experimental data acquired from the physical model. It was found that the CFD model could satisfactorily predict the flow resistance and water surface profile adjacent to the spur dike, including the resulting backwater effect. Furthermore, the CFD model gave a good prediction of the velocity field except for the area behind the spur dike where the effects of diving jet flow over the spur dike was not properly modeled.

A spur dike is a hydraulic structure built on the bank of a river at some angle to the main flow direction. A series of spur dikes in a row may also be placed on one side or both sides of a river to form a spur dike field. Spur dikes are used for two main purposes, namely river training and bank protection. For river training, spur dikes may be used to provide a desirable path for navigation purposes or to direct the flow to a desirable point such as a water intake. For bank protection, spur dikes may be used to deflect flow away from a riverbank and thus protect it from erosion. It has also been observed that spur dikes provide a desirable environment for aquatic habitat. Despite the fact that spur dikes are useful hydraulic structures, they have been found to increase the flow resistance in rivers and hence increase the flow stage. The present study focuses on the quantification of the flow resistance and associated flow stage increase due to a single spur dike and also that of a spur dike field. Increased flow stage is referred to herein as a backwater effect.<p> In the first stage of the study, the flow resistance due to a single spur dike, expressed as a drag force exerted on the flow in an open channel, was studied and quantified. The work was carried out in a rigid bed flume, with the model spur dike being simulated using various sizes of a two-dimensional (2-D) rectangular plate. Several discharge conditions were studied. The drag force exerted by the spur dike for both submerged and unsubmerged flow conditions was determined directly from measurements made using a specially designed apparatus and also by application of the momentum equation to a control volume that included the spur dike. It was found that the unit drag force (i.e., drag force per unit area of dike) of an unsubmerged spur dike increases more rapidly with an increase in the discharge when compared with that of a submerged spur dike. The results also showed that an increase in the blockage of the open channel cross-section due to the spur dike is the main parameter responsible for an increase in the spur dike drag coefficient, hence the associated flow resistance and backwater effect. Based on these findings, relationships were developed for estimating the backwater effect due to a single spur dike in an open channel.<p> In the second stage of the study, the flow resistance due to a spur dike field expressed as a drag force exerted on the flow was quantified and subsequently related to the backwater effect. The work was carried out in a rigid bed flume, with the model spur dikes simulated using 2-D, rectangular plates placed along one side of the flume. For various discharges, the drag force of each individual spur dike in the spur dike field was measured directly using a specially-designed apparatus. For these tests, both submerged and unsubmerged conditions were evaluated along with various numbers of spur dikes and various relative spacings between the spur dikes throughout the field. It was concluded that the configuration of a spur dike field in terms of the number of spur dikes and relative spacing between the spur dikes has a substantial impact on the drag force and hence the flow resistance and backwater effect of a spur dike field. The most upstream spur dike had the highest drag force amongst the spur dikes in the field, and it acted as a shield to decrease the drag force exerted by the downstream spur dikes. From the experiments on the submerged spur dikes, it was observed that the jet flow over the spur dikes has an important effect on the flow structure and hence the flow resistance.<p> In the third stage of the study, the flow field within the vicinity of a single submerged spur dike was modeled using the three-dimensional (3-D) computational fluid dynamic (CFD) software FLUENT. Application of the software required solution of the 3-D Reynolds-averaged Navier-Stokes equations wherein the Reynolds stresses were resolved using the RNG ê-å turbulence model. One discharge condition was evaluated in a smooth, rectangular channel for two conditions, including uniform flow conditions without the spur dike in place and one with the spur dike in place. The CFD model was evaluated based on some experimental data acquired from the physical model. It was found that the CFD model could satisfactorily predict the flow resistance and water surface profile adjacent to the spur dike, including the resulting backwater effect. Furthermore, the CFD model gave a good prediction of the velocity field except for the area behind the spur dike where the effects of diving jet flow over the spur dike was not properly modeled.

This study is to analyze and test the extrusion process of a hollow spur gear and a solid helical product with magnesium alloy. In the hollow spur gear part, firstly, a design criterion to determine the forming parameters is proposed. Then, the Finite Element Analysis is used to simulate the flow pattern of the billet from separating channel, welding chamber to die bearing part. From a series of simulation results, the effect of separating channel length, mandrel entrance angle, welding chamber height, etc. on the radial filling ratio, welding pressure, extrusion load, etc. are found. By using the Taguchi Methods, we can find the most important parameters. Finally, a better die geometry is designed to obtain a sound product. In the helical product part, the Finite Element Analysis is used to get the understandings of radical filling ratio of magnesium alloy in the helical zone. Then, a better die geometry is designed from the results of analyses. Finally, hot extrusion experiments of a hollow spur gear and a solid helical product are conducted. The experimental values of the extrusion load and the product¡¦s dimension are compared with the analytic values to verify the validity of the analytic models.

In this thesis, a highly selective broadband hybrid bandpass filter operating between 0.4-2.0 GHz with a stopband up to 7 GHz is designed and analyzed. The realization is carried out by hybrid method, which combines both lumped and distributed element filters. In this approach, two separate filters, which are lumped highpass with 0.4 GHz corner frequency and distributed stripline lowpass with 2 GHz corner frequency, are combined to get the bandpass filter that has a passband in between 0.4 to 2.0 GHz. The usage of the lumped elements for the highpass filter resulted in a great size reduction compared to distributed element approach. The design software FILPRO&trade / is used to synthesize the trial filters. More than forty filters are synthesized, and among them, the ones that have better properties are chosen for further processes. Optimization, modeling and electromagnetic simulations of the selected lumped and distributed filters are carried out on the software GENESYS&trade / . Distributed filters are also simulated using the software SONNET&trade / . After the simulations, all of the simulated filters are realized and measured, and the level of consistency with the simulations is observed. According to the results of the measurements, the filter combination that has the best combination of low insertion loss, small dimensions, high stopband attenuation and low spur levels is selected for the final bandpass filter structure and a few variants are examined to get the final structure.

Optimum design of multistep gearbox, since many high-performance power transmission applications (e.g., automotive, space industry) require compact volume, has become an important interest area. This design application includes more complicated problems that are not taken into account while designing single stage gear drives. Design applications are generally made by trial and error methods depending on the experience and the intuition of the designer. In this study, using Visual Basic 6.0, an interactive program is developed for designing multistep involute standard and nonstandard spur gearbox according to the American Gear Manufacturers Association (AGMA) Standards 218.01 and 2001- B88. All the equations for calculating the pitting resistance geometry factor I, and the bending strength geometry factor J, are valid for external spur gears that are generated by rack-type tools (rack cutters or hobs). The program is made for twostage to six-stage gear drives, which are commonly used in the industry. Compactness of gear pairs and gearbox, and equality of factor of safety against bending failure is taken as the design objective. By considering the total required gear ratio, the number of reduction stages is input by the user. Gear ratios of every stage is distributed to the stages according to the total gear ratio that satisfies the required precision (from &plusmn / 0.1 to &plusmn / 0.00001 on overall gear ratio) depending on the user selected constraints (unequal gear ratio for every stage, noninteger gear ratio e.g.). Dimensional design is determined by considering bending stress, pitting stress, and involute interference constraints. These steps are carried out iteratively until a desirable solution is acquired. The necessary parameters for configuration design such as number of teeth, module, addendum modification coefficient, are selected from previously determined gear pairs that satisfies the constraints by user interaction considering the performance criterion from the developed program. The positions of gears and shafts are determined automatically in order to keep the volume of gearbox as minimum while satisfying the nonlinear spatial constraints (center distance constraint for proper meshing of gear pairs, face distance constraint for proper assembly of pinion and gear having same shaft, gear interference constraint for preventing interferences between gears, shaft interference constraint for preventing interferences between gears and shafts) by using DLL (Dynamic Link Library) technology of Lingo 8.0 optimization software together with Visual Basic 6.0. If shaft interference constraint is removed then cantilevered mounting of gear pairs would also be possible, otherwise the gears should be mounted between bearings. Visual output of assembly is made by using Autodesk Inventor 7.0, automatically by the program.