Effects of architectural features of air-permeable roof cladding materials on wind-induced uplift loading

Widespread damage to roofing materials (such as tiles and shingles) for low-rise buildings, even for weaker hurricanes, has raised concerns regarding design load provisions and construction practices. Currently the building codes used for designing low-rise building roofs are mainly based on testing results from building models which generally do not simulate the architectural features of roofing materials that may significantly influence the wind-induced pressures. Full-scale experimentation was conducted under high winds to investigate the effects of architectural details of high profile roof tiles and asphalt shingles on net pressures that are often responsible for damage to these roofing materials. Effects on the vulnerability of roofing materials were also studied. Different roof models with bare, tiled, and shingled roof decks were tested. Pressures acting on both top and bottom surfaces of the roofing materials were measured to understand their effects on the net uplift loading. The area-averaged peak pressure coefficients obtained from bare, tiled, and shingled roof decks were compared. In addition, a set of wind tunnel tests on a tiled roof deck model were conducted to verify the effects of tiles' cavity internal pressure. Both the full-scale and the wind tunnel test results showed that underside pressure of a roof tile could either aggravate or alleviate wind uplift on the tile based on its orientation on the roof with respect to the wind angle of attack. For shingles, the underside pressure could aggravate wind uplift if the shingle is located near the center of the roof deck. Bare deck modeling to estimate design wind uplift on shingled decks may be acceptable for most locations but not for field locations; it could underestimate the uplift on shingles by 30-60%. In addition, some initial quantification of the effects of roofing materials on wind uplift was performed by studying the wind uplift load ratio for tiled versus bare deck and shingled versus bare deck. Vulnerability curves, with and without considering the effects of tiles' cavity internal pressure, showed significant differences. Aerodynamic load provisions for low-rise buildings' roofs and their vulnerability can thus be more accurately evaluated by considering the effects of the roofing materials.

FE simulation and experimental tests of high-strength structural bolts under tension

Experimental tests have been completed for high-strength 8.8 bolts for studying their mechanical performance subjected to tensile loading. As observed from these tests, failure of structural bolts has been identified as in one of two ways: threads stripping and necking of the threaded portion of the bolt shank, which is possibly due to the degree of fit between internal and external threads. Following the experimental work, a numerical approach has been developed for demonstration of the tensile performance with proper consideration of tolerance class between bolts and nuts. The degree of fit between internal and external threads has been identified as a critical factor affecting failure mechanisms of high-strength structural bolts in tension, which is caused by the machining process. In addition, different constitutive material laws have been taken into account in the numerical simulation, demonstrating the entire failure mechanism for structural bolts with different tolerance classes in their threads. It is also observed that the bolt capacities are closely associated with their failure mechanisms.

Wastewater treatment by novel hybrid biological – ion exchange processes

This study presents two novel methods for treating important environmental contaminants from two different wastewater streams. One process utilizes the kinetic advantages and reliability of ion exchanging clinoptilolite in combination with biological treatment to remove ammonium from municipal sewage. A second process, HAMBgR (Hybrid Adsorption Membrane Biological Reactor), combines both ion exchange resin and bacteria into a single reactor to treat perchlorate contaminated waters. Combining physicochemical adsorptive treatment with biological treatment can provide synergistic benefits to the overall removal processes. Ion exchange removal solves some of the common operational reliability limitations of biological treatment, like slow response to environmental changes and leaching. Biological activity can in turn help reduce the economic and environmental challenges of ion exchange processes, like regenerant cost and brine disposal. The second section of this study presents continuous flow column experiments, used to demonstrate the ability of clinoptilolite to remove wastewater ammonium, as well as the effectiveness of salt regeneration using highly concentrated sea salt solutions. The working capacity of clinoptilolite more than doubled over the first few loading cycles, while regeneration recovered more than 98% of ammonium. Using the regenerant brine for subsequent halotolerant algae growth allowed for its repeated use, which could lead to cost savings and production of valuable algal biomass. The algae were able to uptake all ammonium in solution, and the brine was able to be used again with no loss in regeneration efficiency. This process has significant advantages over conventional biological nitrification; shorter retention times, wider range of operational conditions, and higher quality effluent free of nitrate. Also, since the clinoptilolite is continually regenerated and the regenerant is rejuvenated by algae, overall input costs are expected to be low. The third section of this study introduces the HAMBgR process for the elimination of perchlorate and presents batch isotherm experiments and pilot reactor tests. Results showed that a variety of ion-exchange resins can be effectively and repeatedly regenerated biologically, and maintain an acceptable working capacity. The presence of an adsorbent in the HAMBgR process improved bioreactor performance during operational fluctuations by providing a physicochemical backup to the biological process. Pilot reactor tests showed that the HAMBgR process reduced effluent perchlorate spikes by up to 97% in comparison to a conventional membrane bio-reactor (MBR) that was subject to sudden changes in influent conditions. Also, the HAMBgR process stimulated biological activity and lead to higher biomass concentrations during increased contaminant loading conditions. Conventional MBR systems can be converted into HAMBgR’s at a low cost, easily justifiable by the realized benefits. The concepts employed in the HAMBgR process can be adapted to treat other target contaminants, not just perchlorate.

Large Eddy Simulations applied to wind loading and pollutant dispersion

The application of Computational Fluid Dynamics based on the Reynolds-Averaged Navier-Stokes equations to the simulation of bluff body aerodynamics has been thoroughly investigated in the past. Although a satisfactory accuracy can be obtained for some urban physics problems their predictive capability is limited to the mean flow properties, while the ability to accurately predict turbulent fluctuations is recognized to be of fundamental importance when dealing with wind loading and pollution dispersion problems. The need to correctly take into account the flow dynamics when such problems are faced has led researchers to move towards scale-resolving turbulence models such as Large Eddy Simulations (LES). The development and assessment of LES as a tool for the analysis of these problems is nowadays an active research field and represents a demanding engineering challenge. This research work has two objectives. The first one is focused on wind loads assessment and aims to study the capabilities of LES in reproducing wind load effects in terms of internal forces on structural members. This differs from the majority of the existing research, where performance of LES is evaluated only in terms of surface pressures, and is done with a view of adopting LES as a complementary design tools alongside wind tunnel tests. The second objective is the study of LES capabilities in calculating pollutant dispersion in the built environment. The validation of LES in this field is considered to be of the utmost importance in order to conceive healthier and more sustainable cities. In order to validate the numerical setup adopted, a systematic comparison between numerical and experimental data is performed. The obtained results are intended to be used in the drafting of best practice guidelines for the application of LES in the urban physics field with a particular attention to wind load assessment and pollution dispersion problems.

Wind loading predictions using computational fluid dynamics

Using Computational Wind Engineering, CWE, for solving wind-related problems is still a challenging task today, mainly due to the high computational cost required to obtain trustworthy simulations. In particular, the Large Eddy Simulation, LES, has been widely used for evaluating wind loads on buildings. The present thesis assesses the capability of LES as a design tool for wind loading predictions through three cases. The first case is using LES for simulating the wind field around a ground-mounted rectangular prism in Atmospheric Boundary Layer (ABL) flow. The numerical results are validated with experimental results for seven wind attack angles, giving a global understanding of the model performance. The case with the worst model behaviour is investigated, including the spatial distribution of the pressure coefficients and their discrepancies with respect to experimental results. The effects of some numerical parameters are investigated for this case to understand their effectiveness in modifying the obtained numerical results. The second case is using LES for investigating the wind effects on a real high-rise building, aiming at validating the performance of LES as a design tool in practical applications. The numerical results are validated with the experimental results in terms of the distribution of the pressure statistics and the global forces. The mesh sensitivity and the computational cost are discussed. The third case is using LES for studying the wind effects on the new large-span roof over the Bologna stadium. The dynamic responses are analyzed and design envelopes for the structure are obtained. Although it is a numerical simulation before the traditional wind tunnel tests, i.e. the validation of the numerical results are not performed, the preliminary evaluations can effectively inform later investigations and provide the final design processes with deeper confidence regarding the absence of potentially unexpected behaviours.

Steel hopper silos filled with granular material: experimental tests on the tensile resistance of corrugated sheets and on the filling and discharging pressures

This thesis addresses various aspects related to silos, from the strength of some structural parts to internal actions due to grain. Two hopper silo models were mainly studied, so the thesis is divided into two parts. The first part focuses only on the silo cylinder and deals with the collapse of a silo due to failure of the vertical walls. We had the opportunity to access data from a real silo and perform tensile tests on corrugated sheets. The theoretical and experimental resistance of the corrugated sheet forming the silo cylinder was studied. The resistance was then compared with the internal actions due to grain prescribed by various standards. The second part, however, focused on the hopper of a silo in which a load test (loading and unloading of the silo) was performed. Through the test data, an attempt was made to reproduce the pressures normal to the hopper through analytical reasoning. The experimental pressures were then compared with the theoretical pressures predicted by the standards. In addition, with mathematical reasoning, an attempt was made to reproduce the horizontal pressure on the vertical walls of the silo from the experimental normal pressure in the hopper. In fact, the test was related only to the hopper part and not to the silo cylinder.

[repeated Fine-needle Aspiration Cytology For The Diagnosis And Follow-up Of Thyroid Nodules].

The recently-proposed Bethesda reporting system has offered clinical recommendations for each category of reported thyroid cytology, including repeated fine-needle aspiration (FNA) for non-diagnostic and atypia/follicular lesions of undetermined significance, but there are no sound indications for repeated examination after an initial benign exam. To investigate the clinical validity of repeated FNA in the management of patients with thyroid nodules. The present study evaluated 412 consecutive patients who had repeated aspiration biopsies of thyroid nodules after an initial non-diagnostic, atypia/follicular lesion of undetermined significance, or benign cytology. The majority of patients were female (93.5%) ranging from 13 to 83 years. Non-diagnostic cytology was the most common indication for a repeated examination in 237 patients (57.5%), followed by benign (36.8%), and A/FLUS (5.6%) cytology. A repeated examination altered the initial diagnosis in 70.5% and 78.3% of the non-diagnostic and A/FLUS patients, respectively, whereas only 28.9% of patients with a benign cytology presented with a different diagnosis on a sequential FNA. Repeat FNA is a valuable procedure in cases with initial non-diagnostic or A/FLUS cytology, but its routine use for patients with an initial benign examination appears to not increase the expected likelihood of a malignant finding.

Usefulness Of Vaginal Cytology Tests In Women With Previous Hysterectomy For Benign Diseases: Assessment Of 53,891 Tests.

To assess the value of vaginal screening cytology after hysterectomy for benign disease. This cross-sectional study used cytology audit data from 2,512,039 screening tests in the metropolitan region of Campinas from 2000 to 2012; the object was to compare the prevalence of abnormal tests in women who had undergone a hysterectomy for benign diseases (n=53,891) to that of women who had had no hysterectomy. Prevalence ratios (95% confidence intervals, 95% CI) were determined, and chi-square analysis, modified by the Cochrane-Armitage test for trend, was used to investigate the effects of age. The prevalence of atypical squamous cells (ASC), low-grade squamous intraepithelial lesion (LSIL), and high-grade squamous intraepithelial lesion or squamous-cell carcinoma (HSIL/SCC) was 0.13%, 0.04% and 0.03%, respectively, in women who had undergone hysterectomy, and 0.93%, 0.51% and 0.26% in women who had not undergone hysterectomy. The prevalence ratios for ASC, LSIL and HSIL/SCC were 0.14 (0.11-0.17), 0.08 (0.06-0.13) and 0.13 (0.08-0.20), respectively, in women with a hysterectomy versus those without. For HSIL/SCC, the prevalence ratios were 0.09 and 0.29, respectively, for women <50 or ≥50years. The prevalence rates in women with a previous hysterectomy showed no significant variation with age. The prevalence rates of ASC, LSIL and HSIL/SCC were significantly lower in women with a previous hysterectomy for benign disease compared with those observed in women with an intact uterine cervix. This study reinforces the view that there is no evidence that cytological screening is beneficial for women who have had a hysterectomy for benign disease.

Durabilidade de compósito biomassa vegetal-cimento modificado por polímero

The durability of the cellulose-cement composites is a decisive factor to introduce such material in the market. Polymers have been used in concrete and mortar production to increase its durability. The goal of this work was the physical and mechanical characterization of cellulose-cement composites modified by a polymer and the subsequent durability evaluation. The work also evaluated the dispersion of acrylic polymer in composites made of Pinus caribaea residues. The physical properties observed were water absorption by immersion and bulk density. Rupture modulus and toughness were determined by flexural test. The specimens were obtained from pads, produced by pressing and wet curing. Samples were subjected to accelerated aging tests by repeated wetting and drying cycles and hot-water bath and natural aging. The scanning electron microscopy (SEM) allowed verifying the fiber and composite characteristics along the time. For the composite range analyzed, it was observed the polymer improved the mechanical properties of composites besides a significant decreasing in water absorption. The use of polymer improved the performance of vegetable fiber-cement composites when compared to the conventional mortar, due to water absorption decreasing.

Influencia de diferentes informações quanto ao tempo de realização do exercicio sobre a atividade eletromiografica e consumo de oxigenio em ciclistas

Universidade Estadual de Campinas . Faculdade de Educação Física

Efeito de onze semanas de treinamento sobre a velocidade critica e o limiar anaerobio em nadadores

Universidade Estadual de Campinas . Faculdade de Educação Física

Aspectos motores da Paralisia Cerebral Espástica diparética : o Nintendo WII 'MARCA REGISTRADA' como atividade motora complementar = Motor aspects of Spastic Cerebral Palsy : the Nintendo WII 'TRADEMARK' as a supplementary motor activity

Universidade Estadual de Campinas . Faculdade de Educação Física

Análise do desempenho em testes de triathlon com diferentes intensidades durante a etapa natação = : Analysis of triathlon trials performance using different intensities during swimming phase

Universidade Estadual de Campinas . Faculdade de Educação Física

Respostas cardio-respiratorias ao exercicio fisico dinamico em mulheres sedentarias no segundo trimestre de gravidez

Universidade Estadual de Campinas. Faculdade de Educação Física

Validade de equipamento eletronico informatizado para analise de movimentos tecnicos do voleibol : um estudo na categoria juvenil

Universidade Estadual de Campinas . Faculdade de Educação Física