In recent times Jamaica has experienced an increase in infrastructure and mineral resource (bauxite) developments. As a result, quarrying activities have also increased to supply the needed construction material. Blasting has been the main technique for loosening insitu rock before transporting to construction site. Consequently there is a growing concern of the effects of blasting activities on the environment. These effects are normally nuisances to the neighbouring residence as they come in the form of: dust, toxic gases, noise, fly rocks and ground vibration. Of the set of nuisances the one that is of most concern is ground vibrations which can cause damage to structures. In most cases worldwide, after blasting activities there are the usual complaints about damage to residence, which is also a focus of the thesis. There have been researches on the subject of ground vibrations to help refute some of these complaints. The works of Lewis Oriard and Charles Dowding are the foundation on which standards and regulations are built as guides to assist blasters in the prevention of creating unnecessary nuisances. Most countries have developed their own regulations with respect to blasting and parameters are set according to the geological conditions. This is of importance as the rock structures determine the transmission of the peak particle velocity. However, most countries in the west adopt standards similar to ones put forward by the United States Bureau of Mines or The Office of Surface Mining. It is my opinion that a whole scale adoption should not take place, as the criteria used may not be suitable for other countries’ geological conditions. For this thesis the aim was to identify a vibration level that will not cause damage to structures close to a quarry. Based on the literature review it was revealed that there are a number of parameters that needed to be considered. These ranges: construction material, age of structures, distance from structures, geology of the location, type and quantities of explosives and the blast design. There was also the review of standards to building threshold with respect to the level of ground vibration. The case study with its main focus on vibration levels at structures in close proximity to the Bengal quarry revealed that a tolerable level can be determined which will not result in any form of damage to the structures. However, having established a PPV limit using the USBM and OSM standards that appears reasonable there is the need for criteria similar to those of the USBM and OSM using blasting and geological conditions in Jamaica. Due to the time constraints (20 wks) it is recommended that future research is carried out in this area especially in relation to assessing the performances of the structures. / <p>Validerat; 20101217 (root)</p>

Acoustic radiation efficiency is defined as the ratio of sound power radiated to the surface vibration power of a piston with equivalent surface area. It has been shown that the radiation efficiency is maximized and may exceed unity when the structural and acoustic wavelengths are approximately equal. The frequency at which this occurs is called the critical frequency and can be shifted with structural modifications. This has proven to be an effective way to reduce noise. The standard radiation efficiency measurement is comprised of an intensity scan for sound power measurement and accelerometer array for spatially averaged vibration determination. This method is difficult to apply to lightweight structures, complicated geometries, and when acoustic sources are in close proximity to one another. Recently, robust particle velocity sensors have been developed. Combined with a small microphone in the same instrument, particle velocity and sound pressure can be measured simultaneously and at the same location. This permits radiation efficiency to be measured using a non-contact approach with a single sensor. A suggested practice for measuring radiation efficiency has been developed and validated with several examples including two flat plates of different thickness, an oil pan, and components on a running small engine.

In this thesis, ground vibrations induced by bench blasting from the Tun&ccedil / bilek Coal Mine, Panel BYH, were measured to find out the site-specific attenuation and to assess the structural damage risk. A statistical approach is applied to the collected data, and from the data analysis an attenuation relationship is established to be used in predicting the peak particle velocity as well as to calculate the maximum allowable charge per delay. The values of frequencies are also analyzed to investigate the damage potential to the structures of Tun&ccedil / bilek Township. A new approach to predict the peak particle velocity is also proposed in this research study. A neural network technique from the branch of the artificial intelligence is put forward as an alternative approach to the statistical technique. Findings of this study indicate, according to USBM (1980) criteria, that there is no damage risk to the structures in Tun&ccedil / bilek Township induced by bench blasting performed at Tun&ccedil / bilek coal mine, Panel BYH. Therefore, it is concluded that the damage claims put forward by the inhabitants of Tun&ccedil / bilek township had no scientific bases. It is also concluded that the empirical statistical technique is not the only acceptable approach that can be taken into account in predicting the peak particle velocity. An alternative and interesting neural network approach can also give a satisfactory accuracy in predicting peak particle velocity when compared to a set of additional recorded data of PPV.

With the development and expansion of traffic systems, problems associated with ground vibrations have required increased attention. Increasing vehicle loads,traffic volumes, and aging roads and railways,vibrations induced by traffic are gradually becoming acrucialproblem.Traffic induced vibrations have much smaller amplitude than those considered in seismic design, but may nevertheless cause annoyance for humans, damage to building, disturb sensitive equipment such as measurements devices, automated manufacturing in factories, etc. It is the purposeto study the effects of the in-filled trench (cell foamis usedas in-filled material in the test)as a wave barrieron the ground vibrationunder excitation of amechanicalvibrator(with an electric motor) in small scale laboratory tests. Laboratory methods are utilized for investigating the influence of cell foam on vibrations in sand by conducting vertical vibration tests with different thickness of cell foam.It is concluded that cell foam used as a wave barriermaterialis significantly working forhighfrequency rangeand for low frequency range the effect is not so effective and obvious.

No description available.

A method for numerical simulation of train induced track vibration and wave propagation in subgrade has been proposed. The method uses a mass to simulate the bogie of a train and considers the effect of rail roughness. For this method, rail roughness is considered as a randomly generated signal and a filter is used to block the undesired components. The method predicts the particle velocity around the track and can be applied to many kinds of railroad trackbeds including traditional ballast trackbed and modern Hot mix asphalt (HMA) trackbed. Results from ballast and HMA trackbeds are compared and effects of HMA layer on damping track vibration and dissipating wave propagation are presented. To verify the credibility of the method, in-track measurements were also conducted. Site measurements included performing geophysical tests such as spectral analysis of surface wave test and seismic refraction test to determine the subsurface conditions at the test site. Ballast and HMA samples were tested in the laboratory by resonant column test to obtain the material properties. Particle velocities were measured and analyzed in the frequency domain. Results from in-track tests confirm the applicability of the numerical method. The findings and conclusions are summarized and future research topics are suggested.

Ground vibrations from blasting are acoustic waves that propagate through the earth. They are also termed seismic waves because their propagation characteristics are similar to the ground motions produced by earthquakes. Amplitude of ground vibration induced by blasting may vary significantly at or around an open pit mine depending on parameters such as the maximum amount of explosive detonating at a time interval and the physical distance between the shot and the location of concern, whereas the frequency of vibration mainly vary depending on the geology and blast delay intervals. Therefore evaluation and assessment of ground vibration condition at or around an open pit mine is necessary. The objective of the proposed research study is to monitor and record the ground vibration and to investigate and assess the vibration conditions at neighbouring districts that are induced by production blasting operations at Usak KiSladag Gold Mine. In this research study, several parameters such as the ground vibration velocity, the amount of charge per delay, the physical distance to the location of monitoring device or residential structures are recorded, analyzed and evaluated together with the frequencies of the seismic waves. The determined ground vibration velocities are compared with the allowable limits given in Turkish Regulation and US Federal Regulation. Thus, the compliance of the ground vibrations with the above mentioned regulations are discussed and assessed. Furthermore, the parameters which affect the ground vibration are discussed and determined. In this study, the monitored and the recorded ground vibrations are evaluated from structural damage potential and human disturbance points of views. It is determined that the ground vibration levels recorded during this study and analyzed from the past records comply with Turkish and US Federal regulations. It is concluded that no damage has been occurred in structures at surrounding settlements and the occupants were not disturbed by the direct effect of vibrations in the past and at present. The analysis proved that the blasting operations to be conducted in the future will not create any damage and disturbance provided that the charge detonated per delay is kept less than 155 kg&amp / #8217 / s.

Behavior of particles in buoyancy driven turbulent flow at Ra ≈ 10º is investigated experimentally. The volume fraction of the particles is low enough for the inter particle influence to be neglected, the mass loading of particle is low enough that the turbulence as not modified, and the particles Reynolds numbers (Re p ) st are small enough that the wake effect can be neglected. The buoyancy driven turbulent flow is created by maintaining an unstable density difference, using NaCl dissolved in water, across the ends of a long vertical tube. There is no mean flow and the turbulence is axially homogeneous. A method for uniform introduction of the particles was devised. Glass particles (S.G=2.4-2.5) of different diameter ranges (50-400 µm) are introduced into this flow. The sizes of particles considered are less than the Kolmogrov length scale corresponding to the turbulence level. The turbulence intensity level was varied in order to match its characteristic time and velocity scale to those of the particles. The ratio of the timescales, the Stokes number; is in the range (0.01-0.55); Stokes number is defined as a ratio of the viscous relaxation time of the particle and a turbulent time scale, and represents the effect of the particle inertia in the interaction with the turbulence, Stk =τp/τk. Another important non-dimensional parameter is the velocity ratio, the k ratio of the particle settling velocity in still fluid to a characteristic turbulence velocity. The flow field is illuminated by a continuous Argon-ion laser and a PHOTRON high- speed digital camera is used for imaging. The raw images are processed to evaluate particle centers followed by their velocity measurements. The objective of the experiment is to check for the effect of the turbulent flow on the sedimentation rate of the heavy particles. This sedimentation rate is compared with the settling velocity obtained in still water. It is expected that within a certain range of Stokes numbers and velocity ratios the sedimentation rate would be substantially changed, and the spatial concentration distribution of the particles may become patchy implying that turbulence may actually inhibit rather than enhance mixing of particles. By varying the turbulence level and particle mean diameter we achieved a set of values for the particle parameters, namely St k. ≈ 0.01, 0.1, 0.14, 0.55 and velocity ratios[[Wp ] St]]≈ 0.2, .0, 0.5, 2.25 respectively. The w rms velocity ratio [[Wp ] St /wf defined as a ratio between the article terminal velocity [Wp ] St and a suitable flow velocity scale; it is a measure of the residence time of the particle in an eddy, in eddy turnover time units. In this study we have considered the turbulence r.m.s velocity for the flow velocity scale.The particle Reynolds number (Re p)st corresponding to these 4 cases were 0.2, 31.5, 4.0, 31.5. Some preliminary quantitative measurements were made only for the 150-200 µm particles and turbulence level w rms ≈ 4.0 cm/s,corresponding to Stk ≈0.14 [[Wp ] St] = 0.5. A quantitative picture was obtained for the other cases. Streak pictures for these four different groups of particles revealed that Stk and the velocity ratio [[Wp ] St ] were important in influencing the particle- w rms turbulence interaction not the Stk alone. The r.m.s velocity fluctuations of particles in both the lateral (utp) and vertical direction (wtp) measured were found to be different from those obtained in still-water case.(For equations, pl see the pdf file)

Y&ouml / rg&uuml / &ccedil / village is within the close neighbourhood of the Western Lignite Corporation Y-3 panel. Although the nearest part of the mine is 1100 m and the farthest part is 2500 m from the village at present, some of the villagers complained about the ground vibration at the past. Therefore the assessment of damage risk and, if any, control and minimization of vibrations constitutes the aim and the scope of this research work. The researh work consists of monitoring of vibration, characterising of the seismic waves by full wave form analysis, and determination of magnitude and frequency of the waves from round blasting practice. Also dominant frequencies are determined, using single-hole blasting records by special software. The analyses are continued by a critical discussion and evaluation, and, proposals for new firing methods are made. The proposed firing methods are validated by further monitoring. As a result the best blasting practice was selected and offered to control and minimize the ground vibration.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Since the industrial processes efficiency depends on the granular flow regime established under given operating conditions on the rotary drum, the ability to predict the particle motion inside this equipment, including the particle properties effect, is of primary importance. So, in this work an experimental and numerical study was carried out in order to investigate: the transition phenomenon between different flow regimes, the mixture and segregation phenomenon and the particle dynamic behavior inside an unbaffled rotary drum, under different operating conditions, using particles of different physical properties. A modification of the Blumberg and Schlünder model equation for rolling-cascading transition was proposed by the introduction of the particle shape effect, represented here by the sphericity. It was observed, for the first time, the hysteresis phenomenon in the transition between cataractingcentrifuging regimes which was shown to be dependent on the physical properties of the particles such as sphericity, density and particle-wall friction coefficient. A new expression relating the critical rotation speed for centrifuging as a function of the filling degree, which takes into consideration the particle properties and the hysteresis effects, was proposed. Regarding the segregation phenomenon, radial segregation due to particle diameter and density differences was observed in all systems studied after a few drum rotations. Size induced axial segregation (banding) was observed, as expected. However density differences alone did not induce axial segregation. As regards the numerical investigation, two different approaches were used for the granular flow prediction inside a rotary drum: Eulerian and Lagrangian. For the Eulerian approach, the results indicated that the kinetic model, which has been successfully applied in many dilute granular flow simulations, may also be applied in the dense granular flow treatment present in rotary drums. It was also observed that, the drag force can be neglected in the case of a rotating drum operated in the rolling regime where there is no fluid entering or leaving the system. Taking the computational efforts into account, this force can be set to zero in the entire calculation domain. For the Lagrangian model calibration, a sensitivity analysis of the numerical dynamic angle of repose due to variations in the friccional coefficient (&#956;f) and the damping ratio (&#946;), both varying from 0.149 to 0.701, was assessed using a Central Composite Design. The smallest deviation from the experimental data when using rice grains was obtained in the simulation whose parameters values were &#956;f = 0.425 and &#946; = 0.149 with an error of about 2.9%. As regards the glass beads, the smallest deviation between experiment and simulation was found using a friction coefficient &#956;f = 0.701 and damping ratio &#946; = 0.425 with an error of about 3.4%. For the case of the rotary drum using rice grains, which are characterized by irregular shapes, the calibrated model was affected by neither the filling degree nor the drum rotation speed. On the other hand, in the case of rounded particles (glass beads), the Lagrangian model parameters should be calibrated to specific conditions of rotation speed and filling degree and cannot be generalized. / A eficiência dos processos industriais desenvolvidos em um tambor rotatório depende da forma como as partículas ou grãos movimentam-se em seu interior. O entendimento dos principais mecanismos que regem estes movimentos e a capacidade de prevê-los através de técnicas de modelagem computacional tornam-se de importância primordial para questões de operação, projeto e otimização. Neste sentido, este trabalho teve como foco a aplicação de metodologias experimentais e numéricas com o intuito de estudar: 1) o fenômeno de transição entre os diferentes regimes de escoamento; 2) mistura e segregação; 3) dinâmica de partículas em um tambor rotatório sob diferentes condições operacionais utilizando partículas com diferentes propriedades físicas. Foi proposta uma nova expressão para a velocidade crítica de rotação para centrifugação função, além do grau de preenchimento do tambor, das propriedades físicas das partículas. Uma modificação no modelo desenvolvido por Blumberg e Schlünder (1996) para a transição rolamento-cascateamento através da inclusão do efeito da forma das partículas foi também introduzida. Observou-se, pela primeira vez na literatura, o fenômeno de histerese quando da transição entre os regimes catarateamento-centrifugação o qual se mostrou dependente das propriedades físicas dos materiais particulados tais como: esfericidade, massa específica e coeficiente de atrito partícula-parede. Foi possível a realização de uma investigação, tanto quantitativa quanto qualitativa, acerca dos efeitos das diferenças de diâmetro, massa específica e da condição inicial do material no interior do tambor rotatório sobre o fenômeno de segregação radial e axial (mistura binária). O fenômeno da segregação axial foi observado apenas quando da diferença de diâmetros entre as partículas. A diferença tão somente da massa específica, independente das condições de velocidade de rotação e grau de preenchimento, não causou segregação axial. No que diz respeito à abordagem numérica, duas diferentes aproximações para a previsão do escoamento granular no interior do tambor foram utilizadas: Euleriana e Lagrangeana. Comparações entre os perfis radiais de velocidade de sólidos experimentais e simulados através do modelo Euleriano mostraram que o modelo cinético-colisional, o qual tem sido aplicado com sucesso em muitas simulações de escoamento granulares diluídos pode, também, ser aplicado no tratamento de um escoamento granular denso presente em tambores rotatórios. Neste caso, observou-se também que a força de arrasto ou resistiva fluido-sólido pode ser negligenciada no caso de um tambor rotatório operando no regime de rolamento, onde não há entrada ou saída de fluido do sistema. No processo de calibração do modelo Lagrangeano através de um Planejamento Composto Central, os valores determinados dos parâmetros coeficiente de atrito (&#956;p) e razão de amortecimento (&#950;) para o arroz foram de, respectivamente, 0,425 e 0,149 (erro relativo de 2,9%), enquanto que para as esferas de vidro foram de 0,701 e 0,425 (erro relativo de 3,4%), respectivamente. Os parâmetros da modelagem Lagrangeana determinados para as partículas arredondadas (esferas de vidro) mostraram-se dependentes das condições operacionais. Já para as partículas irregulares (arroz), a calibração dos parâmetros através de um tambor em escala reduzida, mostrou-se adequada para o emprego na previsão do escoamento em tambores rotatórios em uma escala superior, podendo futuramente ser empregada em uma escala industrial. / Doutor em Engenharia Química