Vacuum-assisted toilets make use of a large pressure difference between the ambient pressure and a vacuum tank to transport waste from the toilet bowl to the septic tank. This process requires 98% less water per flush making it an attractive product for transport vehicles such as airplanes, cruise ships, and trains. Unfortunately, the water savings come at the cost of high noise levels. This thesis investigates the acoustic characteristics of a vacuum-assisted toilet flush and several methods to reduce the radiated noise. Some methods include changing rinse parameters such as rinse pressure, rinse length, and rinse timing, adding structural damping of the bowl to reduce re-radiation, inserting a tube between the bowl and valve that utilizes a larger bend radius and longer tube length than what is currently installed, and modifying the valve. The most effective solution without requiring more water per flush was to insert a tube. The initial peak level was reduced by 16 dB and the steady-vacuum noise was reduced by 5 dB. Evidence of evanescent decay and reduced flow velocity as possible mechanisms for the noise reduction are presented and discussed. Rinse variations show a strong impact of the rinse-tube interaction on the noise reduction. In addition to these techniques, a modified flush plate opening and closing velocity profile is suggested which optimizes the sound generated by the opening and closing of the valve. Finally, a promising dual-valve solution that may take extra coordination of vacuum-assisted toilet manufacturers and airplane/cruise ship/train manufacturers is presented. By placing a secondary valve near the septic tank, the main noise from the valve is significantly reduced.

Use of weight-saving materials to produce lightweight components with enhanced dimensional control is important to the automotive industry. This has increased the need to understand the material behavior with respect to the forming process at the microstructural level. A test matrix was developed based on the orthogonal array of Taguchi design of experiment (DOE) approach. Experiments were conducted for the V-bending process using 6022-T4 AA to study the variation of springback due to both process and material parameters such as bend radius, sheet thickness, grain size, plastic anisotropy, heat treatment, punching speeds, and time. The design of experiments was used to evaluate the predominate parameters for a specific lot of sheet metal. It was observed that bend radius had greatest effect on springback. Next, finite element simulation of springback using ANSYS implicit code was conducted to explore the limits regarding process control by boundary values versus material parameters. 2-D finite element modeling was considered in the springback simulations. A multilinear isotropic material model was used where the true stress-strain material description was input in discrete form. Experimental results compare well with the simulated predictions. It was found that the microstructure of the material used in this study was processed for sheet metal forming process.

No description available.

Yes / The upper reach of the Yellow River from Daliushu to Shapotou consists of five bends and has complex topography. A two-dimensional Re-Normalisation Group (RNG) k-ε model was developed to simulate the flow in the reach. In order to take the circulation currents in the bends into account, the momentum equations were improved by adding an additional source term. Comparison of the numerical simulation with field measurements indicates that the improved two-dimensional depth-averaged RNG k-ε model can improve the accuracy of the numerical simulation. A rapid adaptive algorithm was constructed, which can automatically adjust Manning's roughness coefficient in different parts of the study river reach. As a result, not only can the trial computation time be significantly shortened, but the accuracy of the numerical simulation can also be greatly improved. Comparison of the simulated and measured water surface slopes for four typical cases shows that the longitudinal and transverse slopes of the water surface increase with the average velocity upstream. In addition, comparison was made between the positions of the talweg and the main streamline, which coincide for most of the study river reach. However, deviations between the positions of the talweg and the main streamline were found at the junction of two bends, at the position where the river width suddenly decreases or increases. / National Natural Science Foundation of China (Grants No. 11361002 and 91230111), the Natural Science Foundation of Ningxia, China (Grant No. NZ13086), the Project of Beifang University of Nationalities, China (Grant No. 2012XZK05), the Foreign Expert Project of Beifang University of Nationalities, China, and the Visiting Scholar Foundation of State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, China (Grant No. 2013A011).

<p dir="ltr">Carbon-Carbon (C/C) composites have been shown to be a preferred material for high temperature applications as they retain their properties and performance at temperatures in excess of 2000°C. This study shows that High Temperature Treatment (HTT) at 2400°C for 4 hrs followed by two subsequent Polymer Infiltration and Pyrolysis (PIP) cycles using SC1008 phenolic resin changes the failure mechanism of 2D C/C which has been subject to directional ablation prior to flexural testing. The study observes that prior directional ablation of the non-HTT C/C condition decreases flexural strength by 50.2%, whereas negligible change for the HTT C/C condition was observed (6.6%). This is attributed to the significant degradation of the tensile surface of the non-HTT C/C during ablation corresponding to an average linear thickness loss of 0.321mm (Std Dev = 0.223mm) and average mass loss of 0.364g (Std Dev = 0.196g) while the HTT recorded 0.033mm (Std Dev = 0.005mm) and 0.032g (Std Dev = 0.008g) respectively. The difference in degradation is attributed to the microstructure which was characterised through X-Ray Diffraction and Scanning Electron Microscopy. It is shown that HTT transformed the carbon matrix from a glassy/amorphous matrix to a layered matrix with an indicative increased degree of graphitisation (from 0.52 to 0.69). This not only increased the average density from 1.511 g/cm³ (Std Dev = 0.002 g/cm³) to 1.652 g/cm³ (Std Dev = 0.003 g/cm³) but also increased the average thermal conductivity from 9.1 W/mK (Std Dev = 1.06 W/mK) to 13.3 W/mK (Std Dev = 1.32 W/mK). This ultimately contributed to a reduction in available sites for the oxidation reaction to occur, while also allowing for thermal energy to be conducted away from the ablation surface reducing the amount of heat related damage. For conditions without and with prior ablation damage, the non-HTT C/C is found to fail in matrix dominated tension with the fibres and matrix breaking in a single plane originating at the tensile surface and propagating towards the neutral axis whereas the HTT C/C is found to fail in shear at the neutral axis with the fibres-matrix debonding being the primary failure mechanism. The non-HTT C/C is found to have an average flexural strength of 88.8 MPa (Std Dev = 13.7 MPa) and flexural modulus 81.0 GPa (Std Dev = 10.5 GPa), where the HTT C/C has 196.7 MPa (Std Dev = 31.4 MPa) and 115.2 GPa (Std Dev = 3.3 GPa) respectively. Lastly, this study found that a square notch in the non-HTT C/C condition resulted in a 23.9% and 26.4% reduction in flexural strength for conditions without and with prior ablation damage, respectively. No change in the failure mechanism was observed for notched specimens compared to un-notched specimens, and the debit in strength was attributed to broken fibers created by the notch.</p>

The geomorphic expression, sedimentation, and near-field deformation of a fault system may be characterized to obtain an understanding of its kinematic evolution and potential seismic hazards. The dynamics and deformation history of the Eastern California shear zone (ECSZ), a wide and complex network of right-lateral strike-slip faults, is not well understood, despite hosting three large (>Mw 7.0) earthquake ruptures in recent decades. The low-net slip faults of the ECSZ (each with <10 km) offer a unique opportunity to assess strain distribution in a developing, kinematically immature strike-slip system. To do so, I conducted field-based investigations of these faults within the Mojave Block of the ECSZ. First, I investigated the morphology, structure, and controls of restraining bend growth along the numerous faults of the ECSZ via field mapping and numerical deformational modeling. I found that the ECSZ restraining bends are small (kilometer-scale), exhibit high-angle, doubly fault-bound geometries with positive flower structures, and have self-similar morphologies characterized by a "whaleback" longitudinal profile and an arrowhead shape in map view. Gradual changes in form with increasing restraining bend size suggest a common growth mechanism influenced more by the kinematics of local fault geometries than by the fault's obliquity to plate motion. Modeling results indicate that concentrated shear strain at single transpressional bends facilitates the development of new secondary faults with cumulative strain as a mechanism to accommodate horizontal shortening via uplift between the faults. The ECSZ restraining bends contribute minimally to regional contractional strain due to their small size, steep fault angles, and shallow crustal penetration (< 5 km), which also suggests that they are unlikely to obstruct large earthquake ruptures. Second, I conducted a spatiotemporal slip rate analysis of the Calico fault with new mapping and geochronology of offset alluvial fans from North Hidalgo Mountain. From this work I obtain several findings. 1) The slip rate along North Hidalgo Mountain ranges from 1.5-2.1 mm/yr in the Holocene and 0.8-2.0 mm/yr in the late Pleistocene. 2) The similarity in slip rates between North Hidalgo Mountain and the Rodman Mountains suggests that this 38 km stretch is a kinematically coherent fault segment with a relatively steady slip rate of 1.7 +0.4/-0.3 mm/yr over the past 60 ka. Faster rates reported from Newberry Springs suggest either a significant increase in slip rate from the Rodman Mountains to Newberry Springs or temporal variations in slip rate. 3) The new rates support previous work which showed the central section of the Calico fault has the highest slip rate in the Mojave Block. However, it does not resolve the discrepancy between ECSZ geodetic and geologic slip rates, implying that transient changes in slip rate, or the contribution of off-fault deformation or other structures may be required. Additionally, the lack of geological slip rate data might contribute to this discrepancy if significant spatial and temporal variations exist on other ECSZ faults. / Doctor of Philosophy / The topography and geology within a fault system may be studied to understand tectonic plate motion over time and assess earthquake hazards. The Eastern California shear zone is a complex network of strike-slip faults within the Mojave Desert, which has hosted three large earthquakes (>Mw 7.0) in recent decades. Despite this significant seismic activity, the mechanisms of motion across the numerous faults in the Eastern California shear zone remain poorly understood. The individual faults have accumulated relatively little strike-slip motion since their inception (less than 10 kilometers), offering a unique opportunity to investigate the early-stage kinematics and seismic hazards of a strike-slip fault system. To do so, I conducted field-based investigations of the faults within the Eastern California shear zone. First, I investigated the early evolution and controls of compressional strike-slip fault bends in the Eastern California shear zone. From mapping and numerical modeling, I characterized the shape, structure, and uplift of numerous small compressional bends dispersed across the faults. From these efforts, I found that uplifted crust in the fault bends exhibit self-similar forms with shallow crustal depths (<5 km). Small changes in the shape of these structures occur with increasing size indicating a predictable pattern of growth with increasing cumulative slip that appears to be partially controlled by local fault conditions. Numerical modeling of simple compressional fault bends indicate that shear strain concentrates at bend corners, which may facilitate the growth of a new fault that more efficiently accommodates contraction in the bend via uplift of the crust between the two faults. The compressional strike-slip fault bends in the Eastern California shear zone are too small to significantly impact regional contractional strain and are therefore also unlikely to impede large earthquake ruptures. Second, I studied the slip rate (or rate at which the fault moves) of the Calico fault via new mapping and age data of displaced alluvial fans. I found that 1) the Calico fault at North Hidalgo Mountain slips at a rate of 0.8-2.0 mm/yr since ~70,000 years ago. 2) The slip rates from North Hidalgo Mountain and the Rodman Mountains are similar, indicating that the 38 kilometers between them behaves consistently, with a steady rate of ~1.7 mm/yr over the last ~60,000 years. However, faster slip rates reported at Newberry Springs suggest either a significant increase in slip rate from the Rodman Mountains to Newberry Springs or that it varies over time. 3) These findings confirm that the central Calico fault has the fastest slip rate in the Mojave Block but does not reconcile regional differences between rates from geodetic and geological measurements. The difference between the slip rates measured by geodetic methods and those from geological studies in the Eastern California shear zone suggests that there could be temporary changes in slip rates or that deformation might be occurring in areas away from the main fault. Also, the lack of geological slip rate data might contribute to this discrepancy if significant spatial and temporal variations exist on other Eastern California shear zone faults.

Thesis (MA)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: The subject of this study is Break and Bend verbs in isiZulu, which can be classified as verbs of change of state. This study examines the semantic as well as the syntactic analysis of these verbs of change of state in Zulu. Semantically Bend verbs are divided into verbs denoting the bending of body parts, e.g: thoba, khothema, qomfa, bhena, guqa, vosho, and verbs that denote the bending of body parts as well as physical objects, e.g. goba, qethuka/qethula as shown in the sentences below: Indoda igobe ucingo The man bent the wire. Indoda ithe qethu ikhanda The man bent the head backwards. Inkosikazi igobe amadolo The woman bent the knees. Uthe qethu isigxobo He made the pole bend backwards. The study will demonstrate that Break verbs are semantically divided into verbs denoting break or fracture, e.g. aphula/aphuka; those denoting "break off" e.g. nqamuka/nqamula; a verb denoting "to smash", e.g. fahlaza/fahlaka; those denoting " crack", e.g. chachamba, verbs meaning "to tear", e.g. dabula/dabuka; verbs denoting "to demolish", e.g. bhidliza/bhidlika and verbs denoting "to break open", e.g. havuka I havula. Syntactically, Break predicates may occur as ideophones, which are ergative with transitive/intransitive alternation, e.g. aphulaj aphuka, In addition, Break predicates may consist of ideophones with verbal suffixes: [-k-] is the suffix of intransitive ideophone [-I-] or [-z-] is the suffix of transitive ideophone Intransitive ideophone: Intambo ithe nqamu The rope broke Intransitive verb with [-k-]: Intambo inqamukile The rope broke Transitive ideophone: Indoda ithe nqamu intambo The man broke the rope Transitive verb with [-1-]: Indoda inqamule intambo. The man broke a rope Transitive verb with [-z-]: Indoda iphoqoze intambo. The man broke a bone The study demonstrates that with Bend verbs there are two ergative verbs, namely thoba and goba. -- The study further demonstrates that Bend verbs are mostly intransitive with a shadow argument; there is an ideophone qethu, which takes the transitive / intransitive alternation with the suffix [-k-] for the intransitive and [-1-] for the transitive alternation, respectively. The study provides evidence that Break and Bend verbs are characterised by specific selection restrictions as well as event structures. Some alternations were also investigated in the study, such as the Possessive alternation and Instrument-Subject alternation. Lastly, the Lexical conceptual paradigm and the Lexical Inheritance Structure of each verb were examined. / AFRIKAANSE OPSOMMING: Die onderwerp van hierdie studie is Breek en Buig werkwoorde in isiZulu, wat geklassifiseerword as werkwoorde van toestandverandering. Hierdie studie ondersoek die semantiese en die sintaktiese analise van die werkwoordtipe van toestandverandering in isizulu. Buigwerkwoorde word semanties ingedeel in werkwoorde wat die buig van liggaamsdeleaandui, byvoorbeeld: thoba, khothema, qomfa, bhena, guqa, vosho, en werkwoorde wat die buig van liggaamsdele sowel as die fisiese objekte aandui, byvoorbeeld: goba, qethuka/qethula, soos aangedui word in die sinne hieronder: Indoda igobe ucingo Die man het die draad gebuig Indoda ithe qethu ikhanda Die man het sy kop agteroor gebuig Inkosikazi igobe amadolo Die vrou het (haar) knieë gebuig Uthe qethu isigxobo Hy het die paal agtertoe gebuig. Hierdie studie toon aan dat Breek-werkwoorde semanties ingedeel kan word in werkwoorde wat "breek" aandui, bv. aphula/aphuka: werkwoorde wat "afbreek" aandui, bv. nqamuka/nqamula; werkwoorde wat "flenters breek" aandui, bv. fahlaza/fahlaka; werkwoorde wat "bars" aandui, bv. chachamba, werkwoorde wat "skeur" aandui, bv. dabula/dabuka; werkwoorde wat "ruineer" aandui, bv. bhidliza/bhidlika en werkwoorde wat "oopbreek" aandui, bv. havuka/havula. Breek-predikate kan sintakties as ideofone verskyn, wat ergatief (ergative) is met 'n transitief/intransitief alternasie, bv.. aphula/aphuka. Voorts kan Breek-predikate ook verskyn as ideofone met werkwoordagtervoegsels: [-k-] is die suffiks van die intransitiewe ideofoon [-1-] of [-z-] is die suffiks van die transitiewe ideofoon Intransitiewe ideofoon: Intambo ithe nqamu Die tou het gebreek Intransitiewe werkwoord met [-k-]: Intambo inqamukile Die tou het gebreek Transitiewe ideofoon: Indoda ithe nqamu intambo Die man het die tou gebreek Transitiewe werkwoord met [-1-]: Indoda inqamule intambo. Die man het die tou gebreek Transitiewe werkwoord met l-e-l: Indoda iphoqoze umlenze Die man het die been gebreek Die studie toon aan dat met Buigwerkwoorde, twee ergatiewe werkwoorde gevind is, naamlik thoba en goba. Die studie toon ook aan dat Buigwerkwoorde meestal intransitiewe werkwoorde is wat met 'n skadu-argument verskyn. Daar is 'n ideofoon qethu, wat die transitief/intransitief alternasie vertoon met die suffiks [-k-] vir die intransitief en [-I-] vir die transitief alternasie, respektiewelik Die studie bied bewys daarvoor dat Breek- en Buigwerkwoorde gekenmerk word deur seleksiebeperkings en gebeure ('event') strukture. Sommige alternasies is ook ondersoek in die studie, byvoorbeeld die Possessief alternasie en Instrument-Subjek alternasie. Laastens, is die leksikaal-konseptuele paradigma en die Leksikale-erwingstruktuur van elke werkwoord ondersoek.

This thesis focused on investigating flow, coherent structures, and mechanisms leading to scour around a series of three submerged groynes in a high curvature (radius of curvature (R)/channel width (B)=1.5) channel bend using a Large Eddy Simulation Numerical (LES) model. Flow was investigated during both an initial and a later stage of scour. The results showed that the groynes appeared effective in keeping the main core of high streamwise velocity away from the outer bank wall in the region where they were installed, although high potential still existed for local scour around the groynes. During the initial stage of scour, horseshoe vortices (HVs) showed the greatest propensity to induce scour immediately upstream of the groyne tips. During the later stage of scour, the HV in front of the first upstream groyne (G1) induced very high mean pressure fluctuations on the outer bank wall. Scour was also of very great concern around the tip of G1 due to severe mean bed pressure fluctuations. Downstream of the groyne field, the presence of a counter-rotating outer bank cell was capable of endangering the stability of the outer bank. The second focus of this thesis was to investigate flow in a 135° channel bend using both Reynolds Averaged Navier Stokes (RANS) and LES numerical models. The RANS study examined the effects of curvature ratio (R/B), and aspect ratio (B/H, where H is the inlet flow depth), on secondary circulation strength, and bed shear stresses. The study revealed that a decrease in R/B was associated with an increase in secondary circulation strength and peak bed shear stress. A change in B/H also substantially affected cross stream circulation strength. The LES study was conducted in a 135° (R/B = 1.5) bend flume with a fixed bed corresponding to near equilibrium scour conditions, and the results were compared to a similar high curvature 193° bend numerical study. Inner bank vortices and shear layers were present in both cases although their characteristics were substantially different. Distributions of boundary friction velocities, and turbulence were also quite different for each case.

The effects of pore density and distribution were investigated on the fatigue crack initiation behavior in an A713 sand cast aluminum alloy plate of 12 mm thickness. The applied stress- the number of cycles to failure (S-N) curves of the samples taken from 2 mm and 5 mm from the free surface were obtained using four-point bend fatigue testing at room temperature, frequency of 20 Hz, stress ratio of 0.1, sinusoidal waveform, and in ambient air. The fatigue strengths of both, the 2 mm and 5 mm samples were 60% of the yield strength (σy=171.9 MPa) of the alloy. Optical microscopy, SEM, and EDS mapping were used to characterize pores and particles in 2 mm and 5 mm samples. The average pore sizes of the 2 mm and 5 mm samples were measured to be 10 to 14 μm, and 14 to 32 μm, respectively. The pore number densities in 5 mm and 2 mm samples were comparable, but higher number densities of non-clustered coarse pores (gas pores) were observed in 5 mm samples. The crack population found after fatigue testing showed a Weibull function of stress level. The peaks of strength distributions of fatigue weak link density of 5 mm and 2 mm samples were measured to be 0.017 mm-2 at 67.6 % σy, and 0.01027 mm-2 at 69.5% σy. Crack populations, when normalized by number densities of gas pores (non-clustered) and number densities of shrinkage pores (clustered), giving crack nucleation rate (crack/pore, mm-2), showed a good fit with the Weibull function in 2 mm and 5 mm samples. Shrinkage and gas pores could both become the main crack initiation sites (i.e. fatigue weak links) in this alloy. Higher nucleation rates of gas pores and shrinkage pores were observed in 5 mm samples compared to those rates in 2 mm samples. At high applied stresses, the 2 mm samples showed better fatigue lives than those of 5 mm samples. Fractured surfaces were analyzed using SEM and found that the main crack initiation were predominately from pores. The pores on the fractured surfaces were counted and their depth and width were measured. It was found that the cracks may not necessarily initiate from coarse pores, but sometimes from shrinkage pores (i.e. group of pores). The depth from the free surface, the width, the size, and the orientation of pores are key factors in increasing the driving force for crack initiation and subsequently those pores turn into long cracks. Moreover, the aspect ratios of pores on the main cracks were measured and found that in 5 mm samples, some pores have an aspect ratios of less than 0.7, which means that these pores are elongated in depth and have a narrow width which increase the stress concentration on the surface, thus, increasing the driving force for crack nucleation.

This thesis seeks to understand and explain gendered everyday life in the village of HatNyao in Northwestern Laos, specifically in relation to rubber cultivation, by using an ethnographic approach and methods. The ‘rubber boom’ is changing the landscape of Northern Laos, and in the process is reshaping gendered everyday life. Gender relations in the village of HatNyao are undergoing various transformations whereby previous gender structures start to erode. Additional changes will probably continue to occur, largely due to increasing labour shortages. Gendered everyday life in HatNyao is therefore ‘bending’ with the changes associated with rubber cultivation, as well as in relation to different spaces of the everyday and household diversity. The concept of ‘paradoxical gendered spaces’ is invoked to capture the ways in which the dimensions and activities of the everyday vary with, in particular, ethnicity and age. Most households in HatNyao have improved their living conditions due to rubber cultivation. Nevertheless, inequalities are increasing within the village: better-off households have improved their situation, while for others it has been more difficult to adapt to the new conditions of everyday life and rubber cultivation. As the number of villages introducing rubber in Laos is increasing, alongside the number reaching the crucial tapping stage, it is essential to understand how rubber cultivation in smallholder communities interacts with gender relations and the division of labour. There are thus both ‘good’ and ‘bad’ outcomes from introducing rubber in Laos, since it depends on the context, as well as on the diverse spaces of the everyday.