Dissertations / Theses on the topic 'Surface Blasts'
To see the other types of publications on this topic, follow the link: Surface Blasts.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Surface Blasts.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Andrieux, Patrick. "Application of rock engineering systems to large-scale confined destress blasts in underground mine pillars." Doctoral thesis, Université Laval, 2005. http://hdl.handle.net/20.500.11794/33185.
Full textAbstract:
Cette thèse décrit le développement d’une nouvelle méthodologie qui quantifie les chances de succès d’un tir confiné à grande échelle de relâchement des contraintes dans un pilier de mine souterraine, pour une masse rocheuse et un régime de contraintes donnés. L’approche est basée sur huit paramètres qui sont considérés comme contrôlant ultimement le processus, et dont l’influence et les interactions ont été quantifiées dans un premier temps avec la méthode des Systèmes d’ingénierie du roc (“Rock Engineering Systems”). Ces interactions et degrés d’influence ont ensuite été utilisés pour élaborer la nouvelle méthodologie, qui est basée sur un nouveau paramètre appelé l’Indice de relâchement, qui peut être ‘Faible’, ‘Moyen’, ‘Bon’ ou ‘Excellent’. Il est conclu que cette méthodologie a une valeur pratique élevée de par sa capacité à concevoir adéquatement un tir confiné à grande échelle de relâchement des contraintes dans un pilier de mine, en prenant simplement des mesures qui résultent en une augmentation de l’Indice de relâchement et, donc, des chances de succès du tir
2
Dreyßig, Julia. "Surface marker expression profiles of dendritic cells (DC) generated from blasts in patients with acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) are valuable tools to characterize and quantify DC in experimental settings." Diss., lmu, 2010. http://nbn-resolving.de/urn:nbn:de:bvb:19-117006.
Full text
3
Sun, Wei. "Surface mine blast design and consultant system." Ohio : Ohio University, 1987. http://www.ohiolink.edu/etd/view.cgi?ohiou1183062985.
Full text
4
Kigozi, Gladys Nabagala. "Surface reconstruction of a blast plate using stereo vision." Master's thesis, University of Cape Town, 2007. http://hdl.handle.net/11427/14798.
Full textAbstract:
Includes bibliographical references.This thesis presents method for reconstructing and measuring the profile of a blast metal plate. Among the many methods in computer vision, stereo vision using two cameras is chosen as the range finding method in this thesis. This is because it is a non-contact method and hence eliminates the need to calibrate moving parts. A stereo-rig consists of two calibrated cameras and hence gives two view geometry. Stereoscopic reconstruction relies on epipolar geometry to constrain the relationship between the views. The 3-D point is then estimated using triangulation of the corresponding points from the two views. The blast plates that are reconstructed have highly reflective surfaces. This causes a problem due to specular reflection. This thesis further studies the reflective properties of the metal plate surface. Different methods of scanning the plate using the stereo-rig are investigated. The reconstructions obtained from these methods are analyzed for accuracy and consistency. Since low cost cameras are used in constructing the stereo-rig, the point cloud data obtained is further investigated for consistency by aligning different instances of the reconstruction. This is done using the Iterative Closest Programme (ICP) algorithm which tries to align two sets of data iteratively.
5
Abdul-Hussain, Najlaa. "The Geotechnical Response of Retaining Walls to Surface Explosion." Thesis, Université d'Ottawa / University of Ottawa, 2021. http://hdl.handle.net/10393/42596.
Full textAbstract:
Retaining walls (RW) are among the most common geotechnical structures. They have been widely used in railways, bridges (e.g. bridges abutment), buildings, hydraulic and harbor engineering. Once built, the RW can be exposed to dynamic loads, such as those produced by earthquakes, machines, vehicles and explosions. They must remain operational in aftermath of the natural or human-induced dynamic events. Hence, the understanding of the geotechnical response of RW to these dynamic loads is critical for the safe design of several civil engineering structures such as railways, highways, bridges, and buildings. Although fairly reliable methods have been developed for assessing and predicting the response of RW to dynamic loads induced by earthquakes, there is very little information to guide engineers in the design of RW that are exposed to surface explosions (surface blast loadings). These methods for assessing RW response to earthquake loads cannot directly be applied to the design of RW subjected to surface blast loads. Indeed, blast loads are short duration dynamic loads and their durations are very much shorter than those of earthquakes. The predominant frequencies of a blast wave are usually 2-3 orders of magnitudes higher than those of earthquake wave, and the same can be said for blast wave acceleration as compared to the peak acceleration that results from an earthquake. Thus, RW response under blast loading could be significantly different from that under a loading with much longer duration such as an earthquake. There is a need to increase our understanding of the response of RW to surface explosion loadings since there is a significant increase of terrorist threat on important buildings and some lifeline infrastructures. Transportation structures (bridges, highway, and railway) are unquestionably being regarded as potential targets for terrorist attacks. The purpose of this PhD research is to investigate the geotechnical response of reinforced concrete retaining wall (RCRW) with sand as a backfill material to surface blast loads. The soil-RW model was subjected to a simulated blast load using a shock tube. The influence of the backfill relative density, backfill saturation, blast load intensity, and live load surcharge on the behaviour of RCRW with sand backfill was studied. The dimensions of the stem and heel of the retaining wall in this study were 650 mm (height) x 500 mm (width) x 60 mm (thickness) and 400 mm (width) x 500 mm (length) x 60 mm (thickness), respectively. Soil-RW model was placed inside a wooden box. The overall height of the box was 1565 mm. The retained backfill extended behind the wall for 1300 mm.
Based on the results, it is found that the maximum dynamic earth pressures were recorded at a time greater than the positive phase duration regardless of the backfill condition. The total earth pressure distribution along the height of the wall showed that the magnitude of total earth pressure for loose and medium backfill at the mid-height of the wall slightly exceeded the dense backfill. In addition, the lateral earth pressures increased with the increase in the blast load intensities. On the other hand, under the same load conditions, an increase in the wall movement was noticed in loose backfill, and a translation response mode was evident in this condition. The mobilized passive resistance of the RW backfill induced by blast load was used to determine the force-displacement relationship. Finally, the susceptibility of the RW with saturated dense sand to liquefaction was examined, and it was ascertained that liquefaction was not triggered when the RW was subjected to a blast load of 50 kPa.
The results and findings of this PhD research will provide valuable information that can be used to evaluate the vulnerability of transportation structures to surface blast events as well as to develop guidance for their design.
6
Koneshwaran, Sivalingam. "Blast response and sensitivity analysis of segmental tunnel." Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/78619/1/Sivalingam_Koneshwaran_Thesis.pdf.
Full textAbstract:
This research treated the response of underground transportation tunnels to surface blast loads using advanced computer simulation techniques. The influences of important parameters, such as tunnel material, geometrical configuration of segments and surrounding soil were investigated. The findings of this research offer significant new information on the blast performance of underground tunnels and will contribute towards future civil engineering applications.
7
Gahagan, Shane G. "Pressure-sensitive paint measurements on a rotor disk surface at high speeds." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1997. http://handle.dtic.mil/100.2/ADA333428.
Full textAbstract:
Thesis (M.S. in Aeronautical Engineering) Naval Postgraduate School, June 1997.Thesis advisor, Raymond P. Shreeve. AD-A333 428. Includes bibliographical references (p. 49-50). Also available online.
8
Blaess, Guido [Verfasser]. "Häusung von Surface-acoustic-wave-Sensoren für die Bioanalytik / G. Blaess." Karlsruhe : Forschungszentrum Karlsruhe, 2006. http://d-nb.info/983159173/34.
Full text
9
Mustafa, Kamal. "Cellular responses to titanium surfaces blasted with TiO₂ particles /." Stockholm, 2001. http://diss.kib.ki.se/2001/91-628-4951-4/.
Full text
10
Roger, Eve. "Mines buried in dry and saturated soils : blast experiments, soil modeling and simulations." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAI054/document.
Full textAbstract:
Au cours des conflits récents, les véhicules ont été sujet à des attaques impliquant une grande quantité d'explosif enterré. En général, les planchers sont visés, et leurs déformations absorbent une partie de l'énergie. Le véhicule subit également une impulsion, transmise par la détonation, qui peut blesser gravement les occupants. L'intensité de l'impulsion dépend principalement de trois paramètres: le degré de saturation du sol, la nature du sol dans lequel l'explosif est enterré, et la profondeur d'enfouissement de la charge. Les simulations numériques doivent reproduire le processus intégral de l'explosion, incluant l'initiale interaction entre la charge et le sol, l'expansion des produits de détonation, la propagation de l'onde de choc jusqu'au plancher du véhicule, et la grande déformation des projections de sol. L'information mécanique transmise jusqu'au niveau du plancher doit être suffisamment précise car les effets sur le véhicule constituent l'objectif des simulations. Développer un modèle constitutif de sol est par conséquent délicat.%délicat. un défi. tâche difficile. Le modèle de sol est visco-plastique avec un cap écrouissable, une surface de rupture pour limiter les contraintes de cisaillement et un cut off contre les contraintes excessives de tension. La surface de charge est entièrement lisse afin que les incréments de déformation plastique soient continus. Un mécanisme de rigidification est présenté pour tenir compte de la compression de l'air et des très grandes contraintes dans l'environnement immédiat de la charge. Le taux d'humidité du sol est également pris en compte. Deux séries d'essais ont été réalisés à DGA TT pour servir de référence pour les simulations numériques. Une première campagne a mis en jeu de petites quantités d'explosif à plusieurs profondeurs d'enfouissement. Les pressions aériennes ont été mesurées à plusieurs hauteurs et comparées aux simulations. Un moyen d'essai a été utilisé lors de la seconde campagne d'essais pour mesurer à la fois la déformation d'une plaque représentant un plancher de véhicule, mais aussi l'impulsion transmise par l'explosion enfouie. Un certain nombre de taux d'humidité, profondeurs d'enfouissement, épaisseurs de plaques et gardes au sol a été étudié. Au cours des essais, le sol STANAG, composé de sable et de graviers, défini dans l'AEP 55 relatif au STANAG 4569, a été utilisé. Des simulations Eulériennes ont été réalisées et sont en accord avec les résultats d'essais. Le rôle des trois parties de la surface de charge, des mécanismes de rigidification élastique et d'écrouissage plastique a été évalué. La masse volumique initiale du sol et la position initiale du cap sont les paramètres ayant la plus grande influence sur les pressions aériennes. Quant à l'impulsion, elle est principalement contrôlée par le degré de saturation du solIn recent conflicts, vehicles have been facing underbelly attacks involving a large quantity of buried explosive. A part of the energy is absorbed by the deformation of the belly. Still the vehicle is subjected to the impulse transmitted by the detonation which may severely injure occupants. The intensity of the impulse is highly dependent on three main parameters which are the degree of saturation of the soil, the nature of the soil in which the explosive is buried and the depth of burial of the charge. Computer simulations should follow the complete process of the explosion, including the early interaction of the charge with the soil, the expansion of the detonation products, the propagation of the shock wave up to the vehicle floor, and the large deformation of the soil projections. The mechanical information transmitted up to the floor level should be sufficiently accurate because the impact on the vehicle is the key target of the simulations. Developing a constitutive soil model is therefore a challenging task. The soil model is visco-plastic with a hardening cap surface, a failure surface to limit shear stresses and a cut off surface against excessive tension. The entire yield surface is smooth so that the plastic strain increments are continuous. A stiffening mechanism is introduced to account for air compression and accommodate the huge stresses in the immediate neighborhood of the charge. The water content of the soil is also taken into account. Two sets of experiments were carried out at DGA TT to serve as a reference for computer simulations. A first campaign involved small quantity of explosive at several depths of burial. The aerial pressures were measured at various heights and compared to simulations. The second set of experiments used a test rig to measure both the deformation of a floor simulating plate and the impulse transmitted by the buried explosion. A range of soil water contents, depths of burial of the explosive, plate thicknesses and stand off distances has been explored. For all the experiments, the sandy gravel STANAG soil defined in AEP 55 of STANAG 4569 has been used. Eulerian simulations were run and fit with these experiments. The roles of the three parts of the yield surface, of the elastic stiffening and plastic hardening mechanisms could be assessed. The initial soil density and the initial cap position were found to have the largest influence on aerial pressures. As for the impulse transmitted to the metallic plate, it was observed to be mostly controlled by the degree of saturation of the soil
11
Jayasinghe, Laddu Bhagya. "Blast response and vulnerability assessment of piled foundations." Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/71184/1/Laddu%20Bhagya_Jayasinghe_Thesis.pdf.
Full textAbstract:
This research treated the response of pile foundations to blast loads. The influence of important parameters was investigated. The research techniques and the results will enable safer design of pile foundations that are vulnerable to blast loads.
12
Schneider, Nathan A. "Prediction of surface ship response to severe underwater explosions using a virtual underwater shock environment." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Jun%5FSchneider.pdf.
Full textAbstract:
Thesis (Mechanical Engineer and M.S. in Mechanical Engineering)--Naval Postgraduate School, June 2003.Thesis advisor(s): Young S. Shin. Includes bibliographical references (p. 161-162). Also available online.
13
Khameneifar, Farbod. "Section-specific geometric error evaluation of airfoil blades based on digitized surface data." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/55847.
Full textAbstract:
Manufactured aero-engine blades are normally inspected in sections. Given discrete section-specific data points, the related geometric error evaluation task for three-dimensional tolerances of the blades is challenging and not yet well studied by researchers. Particularly, the existing method shows limited effectiveness in detecting position error and difficulty in accurate estimation of orientation error of airfoil sections. Moreover, touch-probes on a coordinate measuring machine are traditionally used to collect sectional coordinate data, which is a lengthy process as the data is collected through probe contact with the blade surface. Blade manufacturers would rather use 3D laser scanning that can complete data acquisition much faster. However, this poses a new challenge to data analysis. The collected set of points, referred to as point cloud, is all over the surface rather than at the desired, pre-specified sections. Thus, generating reliable section-specific data from the massive, unorganized scanned data points remains a problem to be solved. This thesis first presents a new methodology for evaluating three-dimensional tolerances of airfoil sections based on reconstructing the airfoil profiles from section-specific data points. According to a given measurement uncertainty, a progressive curve fitting scheme is proposed to generate the airfoil profile that meets the uncertainty constraint. Subsequently, the profile is utilized in related feature extraction of the proposed error evaluation approach. The second part of the thesis focuses on generating the reliable section-specific data points from the complete surface scan. An adaptive surface projection of data points onto the pre-specified section plane is proposed. A localized surface-fitting scheme is devised for this purpose. The main challenge lies in the selection of local data points, referred to as local neighborhood, for surface fitting. In particular, with the non-uniform distribution of data points in a noisy point cloud, existing neighborhood selection methods lead to biased fitting results. To avoid bias, a method of establishing balanced local neighborhood for surface fitting is proposed. An automated technique is also presented for systematic identification of eligible points for projection. The proposed computational framework in this thesis enables fully automatic and accurate evaluation of geometric errors using the latest high-speed geometric inspection platform.Applied Science, Faculty of
Mechanical Engineering, Department of
Graduate
14
Cullen, William Roderick. "The colonisation and establishment of surface invertebrate communities in restoration blasted limestone quarries." Thesis, Manchester Metropolitan University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262357.
Full text
15
Macquart, Terence. "Aeroelastic analysis of wind turbine smart blades utilising multiple control surfaces." Thesis, Northumbria University, 2014. http://nrl.northumbria.ac.uk/27223/.
Full textAbstract:
The aeroelastic control of wind turbine blades employing active flow controllers is part of an ongoing research effort aiming to alleviate blade loads. Over the past years, the growing body of literature has confirmed the preliminary potential of active flow controllers and, in particular, of control surfaces in relieving wind turbine fatigue and extreme loads. The aim of present research is to investigate the feasibility, design and capability of a multi-component aero-structural load control system utilising light control surfaces such as trailing edge flaps and microtabs. This is achieved through the design of load alleviation control systems, and a detailed understanding of the aeroelastic dynamic of wind turbine blades equipped with control surfaces. As part of this research, a Wind Turbine Aeroelastic Control (WTAC) simulator has been developed. WTAC is the combination of an unsteady aerodynamic module, a structural finite element analysis module, and a control module incorporating the aerodynamic models of control surfaces. The aeroelastic study of the NREL 5MW wind turbine whose blades are equipped with trailing edge flaps and microtabs is carried out using WTAC.
16
Ataman, Nihat. "Utilization Of Industrial Wastes Of Turkey As Abrasive In Surface Preparation Technologies." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606911/index.pdf.
Full textAbstract:
Surface preparation is the key factor in determining the success of a protective coating system and its ultimate objective is to create proper adhesion of a coating over an underlying substrate.
Abrasive blast cleaning involves mechanical cleaning by the continuous impact of abrasive particles at high velocities on to the substrate in a jet stream of compressed air. Industries that use abrasive blasting include the shipbuilding industry, automotive industry, and other industries that involve surface preparation and painting.
Materials from different origins can be used as a blasting media including coal slag, smelter slag, mineral abrasives, metallic abrasives, and synthetic abrasives.
Purpose of this thesis is to investigate the usability of industrial wastes (coal slag, smelter slags, etc.) of Turkey as abrasives in surface preparation technologies.
Four different slag samples of three sources, namely coal furnace slag sample from Çayirhan thermal power plant, ferrochrome slag sample from Eti Krom A.S., granulated blast furnace and converter slag sample from Eregli Iron and Steel Works were studied within the scope of this thesis work. The samples were prepared by crushing and screening. The chemical composition and physical characteristics of the samples were determined. All the samples were tested in industrial scale. Test results showed that the converter slag meet all the specifications for abrasives and it can be used in blast cleaning operations. However, coal furnace slag, granulated blast furnace slag and ferrochrome slag are not suitable to be used as abrasive in surface preparation technologies.
17
Delibas, Tughan. "Effects Of Granulated Blast Furnace Slag Trass And Limestone Fineness On The Properties Of Blended Cements." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614072/index.pdf.
Full textAbstract:
The aim of this research was to determine the effects of the fineness of different mineral additives on loss on ignition, heat of hydration, physical, mechanical and chemical properties of blended cements. For that purpose, portland cement clinker was replaced with granulated blast furnace slag (GBFS), natural pozzolan (NP) and limestone (L) at 6%, 20% and 35% replacement levels. Blended cements containing GBFS and NP were ground to a fineness of 3000, 5000 and 6000 cm2/g. Cements containing L were ground to 3000 cm2/g, 4000 cm2/g and 4500 cm2/g. All of the blended cement types mentioned above were both interground and separately ground to the specified fineness levels. Therefore, a total of 57 different cements were produced. Loss on ignition, heat of hydration, chemical, mechanical and physical analyses were performed on the produced cements. Moreover, the chemical analyses of the cements were obtained for cement particles finer (-45&mum) and coarser (+45&mu
m) than 45 &mu
m in order to determine the ingredients of -45 &mu
m, which is known to be more reactive. As a result it was shown that the grindability differences of the cement ingredients affect the properties of blended cements. An increase in the specific surface area increases both the compressive strength and heat of hydration values and adversely affects the loss on ignition values. The results also showed that if the cement particles were ground finer, it was more prone to moisture which resulted in higher loss on ignition values after longer periods.
18
Edling, Harald T. "An approach to the manufacture of free form surfaces embodying structured areas to increase hydraulic efficiency." Thesis, Glasgow Caledonian University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369993.
Full text
19
Becker, William J. "Dynamic surface temperature measurement on the first stage turbine blades in a turbofan jet engine test rig." Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/43743.
Full textAbstract:
Turbine blade surface temperatures were studied during transient operation in a
turbofan engine test rig. A single fiber radiation pyrometer was used to view the suction
side of the blades from approximately 60 percent axial chord to the trailing edge at an
average radial location of 70 percent blade height. A single ceramic-coated blade
produced a once-per-revolution signal that allowed for the tracking of individual blades
during the transients. The investigation concentrated on the light-off starting transient
and the transients obtained during accelerating and decelerating between power settings. During starting and acceleration transients, the blade surface temperature gradient was observed to reverse. This phenomenon was most apparent during starting when the trailing edge was initially much hotter than the 60 percent chord location, resulting in large temperature gradients. In steady operation the trailing edge temperature was lower than the 60 percent chord location, and the gradients were less severe. During deceleration transients, the trailing edge cooled more rapidly than the 60 percent chord location. This resulted in larger temperature gradients than were seen in steady operation, but no profile inversion was observed. These temperature gradients and profile inversions represent a cycling of thermally-induced stresses which may contribute to low cycle fatigue damage. A simple one-dimensional heat transfer model is presented as a means of explaining the different heating rates observed during the transients.Master of Science
20
Hacking, Steven Adam. "The osseous response to corundum blasted implant surfaces in a canine total hip arthroplasty model." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0007/MQ44013.pdf.
Full text
21
Hacking, Steven Adam. "The osseous response to corundum blasted implant surfaces in a canine total hip arthroplasty model /." Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=20501.
Full textAbstract:
The purpose of this study was to examine the radiographic and histologic response. to corundum blasted implant surfaces of varying roughness in a canine total hip arthroplasty model. Three types of tapered femoral implants were made from titanium alloy and were identical in every respect except surface finish. The entire surface of the femoral implant possessed either a 2.9, 4.2 or 6.7 micrometer average surface roughness (Ra) from blasting with 60, 24, or 16 grit corundum particles, respectively. Staged bilateral total hip arthroplasties were performed such that each dog received a 60 grit on one side and a 24 grit or 16 grit implant on the contralateral side. Twenty-two stems in 11 dogs were evaluated at 6 months. The appearance of the bone implant interface was qualitatively characterized. Bone apposition and average bone-implant contact length were determined. Twenty-one of the stems demonstrated osseointegration while one stem developed a stable fibrous interface. All three types of corundum blasted implants demonstrated consistently high amounts of bone apposition, averaging 30.5%. Abundant new peri-implant bone consistently formed, particularly within the intramedullary canal where trabeculae spanned implant-cortical gaps up to 5 mm and established osseointegration ration. There was no statistical difference amongst bone apposition with the 60, 24, and 16 grit stems which averaged 31.7%, 32.0% and 27.9% respectively. However, the pattern of new bone formation was different in that the average length of each region of bone apposition for the 60 and 24 grit surfaces was 50% greater than that for the coarser 16 grit surface (p < 0.02). Through detailed qualitative and quantitative radiographic and histologic elucidation of the osseous response to corundum blasted hip implant surfaces, this study provided new understanding of their potential for biologic fixation. Corundum blasted surfaces represent an important and valuable technology for the design of non
22
Ekström, Erik. "Effect of texture and blasting pressure on residual stress and surface modifications in wet sand blasted α-Al2O3 coating." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-122508.
Full textAbstract:
Recently, wet sand blasting on coated cutting tool inserts has drawn interest to the tooling industry due to its positive effects on cutting performance and tool life. This performance boost has partly been attributed to the buildup of compressive residual stresses in the coating during the blasting process. However, the mechanism of forming residual stresses in ceramic coatings during sand blasting is not fully understood. This work utilize x-ray diffraction as the main tool to study the formation and relaxation of residual stresses after wet sand blasting and annealing on 001, 012 and 110 textured α-Al2O3 coatings. To minimize the influence of stress gradients in the samples, all stress measurements were set up with a fixed analysis depth of 2 µm. Sand blasting was made with an alumina based slurry at 2, 3.2 and 4 bar pressure and the anneal was done at temperatures from 400 to 1000 °C for 2 hours or more. The coating hardness was evaluated by nanoindentation. Finally, the activation energy for the relaxation of residual stresses was estimated using the Zener-Wert-Avrami function. The results reveal the highest compressive residual stress with up to -5.3 GPa for the 012 texture while the stresses for the 001 and 110 textures peaked at -3.1 and -2.0 GPa, respectively. Further, a hardness gradient was present after blasting of the 001 and 012 textured samples indicating a higher stress at the surface of the coating. The 110 textured sample is the most brittle resulting in flaking of the coating during sand blasting. The different deformation mechanisms are related to difference in active slip planes between coatings with different textures. Both the stress and hardness decreased after heat treatment and the activation energy for stress relaxation was found to be as 1.1 ± 0.3 eV, 1.9 ± 0.2 eV and 1.2 ± 0.1 eV for the 001, 012 and 110 textures, respectively.
23
Russ, Thomas William. "A surface flow visualization study of boundary layer behavior on the blades of a solid-wall compressor cascade at high angles of attack." Thesis, Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/53161.
Full textAbstract:
The oil-film surface flow visualization technique was applied to circular arc compressor blades in a solid wall, high aspect ratio cascade for the purpose of describing the transition from corner stall to full blade stall, and the blade surface flow under fully stalled conditions. Photos of the visualizations for three stagger angles are presented and analyzed. A map quantitatively describing the observed boundary layer development at midspan is presented.
The most interesting discovery of the work showed the suction surface flow to be essentially two-dimensional, in the geometric sense, preceding and following the transition to a fully separated flow at the leading edge. Corner stall was the observed three-dimensional mechanism prior to full stall. For fully-stalled conditions, the three-dimensional mechanism took the form of recirculating flow regions at the blade ends. Complete separation at the leading edge occurred at lower angles of attack for the higher stagger angles. Special blade oil-flow tests were conducted to evaluate Reynolds number and tip clearance effects on boundary layer development.
The experimental work was done as part of a larger research program aimed at measuring and predicting the stalled performance of a compressor cascade.Master of Science
24
Cruz, Eden E. "THE EFFECT OF RECOMBINANT HUMAN BONE MORPHOGENETIC PROTEIN-2 ON THE OSSEOINTEGRATION OF TEMPORARY ANCHORAGE DEVICES." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/331.
Full textAbstract:
Titanium has been widely used for dental implants, and in particular, roughened titanium surfaces have provided a means for increasing bone apposition and strengthening the implant-to-bone interface. Finding a way to further increase osseointegration is important because there is a significant clinical benefit to patients if a stable anchor can be established instead of anchoring orthodontic hardware to the molars. In this study, the effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) on the ability of temporary anchorage devices (TADs) to osseointegrate was investigated. The temporary anchorage devices (TADs) used in this study were manufactured from commercially pure titanium and divided into 2 types of treatments: (1) sandblasted and acid-etched (i.e. the control) and (2) sandblasted and acid-etched treated with Medtronic INFUSE® Bone Graft (recombinant human bone morphogenetic protein-2 placed on an absorbable collagen sponge). The implants were placed on the cranial bones of 10 adult male Sprague-Dawley rats. The rats were euthanized by carbon dioxide asphyxiation 6 weeks following surgery for histological examination and biomechanical testing. The results from visual inspection and biomechanical testing showed that the sandblasted and acid-etched TADs treated with rhBMP-2 promoted better osseointegration than TADs that were only sandblasted and acid-etched. Specifically, surface modified TADs treated with rhBMP-2 on bottom showed an increased surface coverage by bone and an increase in the adhesion strength at the TAD-to-bone interface.
25
Jones, Alistair. "Co-located collaboration in interactive spaces for preliminary design." Phd thesis, Université de Technologie de Compiègne, 2013. http://tel.archives-ouvertes.fr/tel-01067774.
Full textAbstract:
The preliminary design phase occurs near the launch of an engineering project, normally after an initial requirements gathering phase. Through a series of meetingswhich gathers the key actors of a project, effective preliminary design involves discussion and decision-making punctuated by group creativity techniques. These activities are designed to explore the potential solutions of the problem, such asbrainstorming or causal analysis, or to address the project itself, such as collaborative project planning. Such activities are usually conducted in traditional meeting rooms with pen and paper media, which requires significant time and effort to prepare, perform, and later render into a digitally exploitable format. These processes have resisted previous attempts of computer-supported solutions, because any additional instruments risk obstructing the natural collaboration and workflow that make these activities so beneficial. Over the past decade, technologies such as interactive table tops, interactive wall displays, speech recognition software, 3D motion sensing cameras, and handheld tablets and smartphones have experienced significant advances in maturity. Theirform factors resemble the physical configuration of traditional pen-and-paper environments,while their "natural" input devices (based on multi-touch, gestures, voice, tangibles, etc.) allow them to leverage a user's pre-existing verbal, spatial,social, motor and cognitive skills. Researchers hypothesize that having these devices working in concert inside interactive spaces could augment collaboration forco-located (i.e. physically present) groups of users.There currently exist several interactive spaces in the literature, illustrating awide range of potential hardware configurations and interaction techniques. The goal of this thesis is first to explore what qualities these interactive spaces should exhibit in their interaction design, particularly with regard to preliminary designactivities, and second, to investigate how their heterogeneous and distributed computing devices can be unified into a flexible and extensible distributed computing architecture. The first main contribution of this thesis is an extensive presentation of an interactive space, which at its core uses a configuration not yet fully explored inprevious literature : a large multitouch table top and a large multitouch interactive Abstract board display. The design of this interactive space is driven by observations o fgroups engaged in preliminary design activities in traditional environments and a literature review aimed at extracting user-centered design guide lines. Special consideration is given to the user interface as it extends across multiple shared displays, and maintains a separation of concerns regarding personal and group work. Finally, evaluations using groups of five and six users show that using such an interactive space, coupled with our proposed multi-display interaction techniques, leads to a more effective construction of the digital artifacts used in preliminary design.The second main contribution of this thesis is a multi-agent infrastructure forthe distributed computing environment which effectively accommodates a widerange of platforms and devices in concerted interaction. By using agent-oriented programming and by establishing a common content language for messaging, the infrastructure is especially tolerant of network faults and suitable for rapid prototyping of heterogeneous devices in the interactive space.
26
Dohnal, Jakub. "Kotel na spoluspalovaní vysokopecního plynu a koksárenského plynu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-242878.
Full textAbstract:
This diploma thesis deals with the constructional and calculation design of boiler for blast furnace and coke gas mixture combustion, including sizing of the heating surfaces. The opening section is dedicated to a brief characterization of burned fuels. The following chapter shows the parameters and composition of the resulting fuel mixture. The main part of this thesis involves; determining the stoichiometric amount air required for combustion and the resulting flue gas, determining the boiler efficiency and steam production rate, calculations regarding the combustion chamber and the detailed design of the individual heat exchangers. At the end of the thesis the heat balance of the entire boiler is verified. Drawing documentation of boiler is also part of this diploma thesis.
27
Mishra, Ashutosh. "Designing of Surface Blasts - A Computational Approach." Thesis, 2009. http://ethesis.nitrkl.ac.in/34/2/10505029.PDF.
Full textAbstract:
A major part of mineral production comes from surface mining and there has been a rapid growth in this sector with the deployment of high capacity equipment .Increased production can be achieved from large capacity surface mines using heavy earth moving machineries. These machineries involve high capital cost, and thus, the mining engineers should plan to achieve the best performance from these machineries. Performance of them, especially the excavating and transporting equipments are largely depending on the blast results, particularly, fragment size, distribution and muck profile. Thus, proper blast design with a computational approach is a vital factor that affects the cost of the entire mining activities.
28
Parida, Abinash. "Evaluation of Blasting Efficiency in Surface Mines." Thesis, 2016. http://ethesis.nitrkl.ac.in/8463/1/2016_AParida_MTech(R)_Evaluation.pdf.
Full textAbstract:
Drilling and blasting are the major unit operations in opencast mining. In spite of the best efforts to introduce mechanization in the opencast mines, blasting continue to dominate the production. Beside the production in open cast mining blasting and vibration also cause environmental problem. In bench blast design, not only the technical and economic aspects, such as block size, uniformity and cost, but also the elimination of environmental problems resulting from ground vibration, air blast and fly rock should be taken into consideration. The evaluation of ground vibration components plays an important role in the minimization of the environmental complaints. Odisha is rich in iron ore deposit and the mines invariably need blasting for loosen the rock mass. These are frequent complaints from the people surrounding the zone about adverse effect of blasting. This study is an attempt to evaluate same of those aspects. Two active iron ore mine have been considered for the analysis of ground vibration, air over pressure, flyrock as well as fragmentation parameters. There exist a few established approaches as USBM, Langefors-Kilstrom, Ambraseys-Hendron, Indian standard and CMRI to predict those. In this investigation the utility of those approaches are evaluated. It was observed that the two region Koira and Daitarido not confirm strongly to the five approaches. Artificial neural network is a technique that is gain wide acceptance even in heterogeneous condition. This study also finds that the prediction by ground vibration, air over pressure and fly rock by ANN would be better alternative. Model equation has also been developed with ANN approach. Mutual relations between stemming length, depth, fragmentation size, powder factor, explosive charge have also been determined.
29
Barik, Santanu Kumar. "Application of inverse theory in open pit blasting." Thesis, 2013. http://ethesis.nitrkl.ac.in/4697/1/109MN0102.pdf.
Full textAbstract:
Blasting is a crucial part in mining operation. Proper blasting practice not only reduces the adverse effects like peak particle velocity but also improve the production and productivity. The blasting in open pit mine is controlled by number of parameters like spacing, burden, quantity of explosive etc. The production and productivity are measured by power factor, throw, and drop. Numerous models have been developed to calculate the powder factor, drop, and throw using spacing, burden, hole depth and explosive charges etc. as input variables, which means that for known input variables, powder factor, throw, and drop can be calculated. However, field mining engineers are more interested about what should be the suitable values of input parameters to get a specific factor, throw, and drop. In most cases this has been done on a trial and error basis to fix the values of input parameters. A technique was developed to predict a nearly optimum set of blast design parameters from the nine variable design parameters (drill penetration rate, bench height, burden, spacing, hole depth, sub-grade drilling, stemming, blast round, and length to width ratio) that largely affect the shape (throw and drop) and the PF values of blasted muck piles. A stepwise forward multivariate regression algorithm was applied to generate optimum forward equation for powder factor, drop, and throw parameters. A linear inverse theory was applied to develop linear equations for independent variables. The developed method was applied in a limestone case study mine and results revealed that the this approach could be a good methods for selection of blasting parameters to get desire outputs.
30
Singh, Vivek pratap. "Comparative Study of Different Faliure Criterion on rock." Thesis, 2018. http://ethesis.nitrkl.ac.in/9480/1/2018_MT_216MN1469_VPSingh_Comparative.pdf.
Full textAbstract:
Rock is a solid aggregate of the one or more minerals. Rocks are of various types depending on their formation. Rocks are generally categorized as Igneous, Sedimentary and metamorphic. The general theory which prevails for the formation of rock is, melted rocks or rather magma that comes out earth crust cools and later solidifies to form different types of rocks.Rocks are heterogeneous in nature.Being heterogeneous in nature, it is very challenging to predict the behavior of rocks and to give a general theory of failure. There are various factors which affects the behavior of the rock. The factors which affect the most are confining pressure, temperature, rock type etc. The only way to know the behavior of rock is by testing in the laboratory. As the in-situ rocks are subjected to various type of loading. Rocks in the laboratory were subjected to similar type of conditions. Two types of testing were done i.e. destructive and non-destructive. Destructive testing is technique in which application is made to fail in uncontrolled manner to find out major principal stress, minor principal stress, tensile strength, compressive strength, cohesion, angle of friction. The test which were conducted to find out the above mentioned parameters are slack durability test, Brazilian tensile test, Triaxial test,Protodyakonov impact strength. Ultrasonic and rebound hammer techniques were used for non-destructive testing. These techniques were used to find out some other mechanical parameters. There are myriad types of failure criterion which are used to analyze the failure of rock. The criteria which were used are Mohr-coulomb, Hoek-Brown, Yudhbir and Ramamurthy respectively to find out the best failure criteria for Basundhra region. It was concluded that the Ramamurthy comes out to be the best failure criteria for Basundhra region
31
Rajput, Ashish. "A Study of Energy in Rock Blasting." Thesis, 2016. http://ethesis.nitrkl.ac.in/8118/1/2016_MT_711MN1088_Study_of_energy.pdf.
Full textAbstract:
Creation impacts have been observed in quarry so as to evaluate the quantifiable structures of energy in which the energy conveyed by the unstable is changed in rock impacting. The seismic field from Minimate readings, the introductory speed of the impacted rock face acquired utilizing Gurney condition, and the section size disseminations from picture investigation of the muckpile material are utilized to decide the seismic wave energy, the Kinetic energy and the Fragmentation energy, individually, moved in the impacting procedure. The impacting information and the techniques for figuring of the energy terms from those are depicted in subtle element. The most extreme aggregate energy measured records for not more than 26% of the accessible dangerous energy in the event that this is appraised as the warmth of blast, however lower figures are normally acquired. Sample of iron ore collected for laboratory experiment to find out the fragmentation energy with the help of “WipFarg Software (used for sieving of different rock sizes)”, drilling and blasting data, average size of fine and coarser particles, data for ppv to find out seismic energy, also Gurney equation for calculation of kinetic energy The energy discharged by the explosive, borne in the detonation endless supply of the chemical reaction, is changed over into heat and work to the surroundings as indicated by the first principle of thermodynamics.
Some of these structures get to be obvious amid the impact, to be specific:
• the fracture work, that eventually shows up as new surface in the rock fragments;
• the work exchanged as shock wave into the rock, that proliferates as plastic and at last elastic waves, showing up as seismic wave or ground vibration; and
• the work to uproot the rock and shape the muckpile, that shows up as kinetic energy conferred to the rock.
Other energy exchange happens, in a less evident manner, as takes after:
• expansion work of the fractures, that is consumed as elastic and plastic miss happening of the rock in the surface of the fractures as they are infiltrated by the gasses;
• heat exchanged to the rock from the hot detonation items; and
• heat and work passed on as enthalpy of the gasses venting to the air through open fractures and stemming.
The energetic analysis provides a good insight of the explosive/rock interaction and a better understanding of the blasting process, encompassing a broad range of scientifically challenging subjects .For each energy component, first of all some experiments have been carried out in laboratory and some data collected from Iron Ore Mine to find out some results for different energy. Then with the help of some software and some equations from literature helped me to do my project work with efficiency. Energies ratios with respect to the total explosive energy are: Fragmentation energy is 31.45%, seismic energy is 1.69%, kinetic energy 13.599%. Total explosive energy measured is equal to 2.434 GJ
32
Patel, Sucharita. "Development of Adsorption Media by Using Industrial Waste: Red Mud for the Removal of As (V) Ions from Water." Thesis, 2018. http://ethesis.nitrkl.ac.in/9402/1/2018_PhD_SPatel_512MN1003_Development.pdf.
Full textAbstract:
In this study cow dung identified as a neutralizing agent for red mud (RM). Present research estimated a significant reduction in pH value of red mud (10 g) from 10.28 to 8.15 and reduction in alkalinity of ~148 mg/L from ~488 mg/L by adding 80g of cow dung in forty days of anaerobic condition. Titration method, SEM-EDX, FT-IR and XRD applied for characterizing neutralized red mud (NRM). XRD results exhibits a high intensity of quarts and found new compound, the calcium carbide. The acid neutralizing capacity (ANC) of NRM reduce to ~0.87 from~1.506 mol H+/Kg. Based on the resultant research, present study propose cow dung as an efficient neutralizing agent for reducing the pH and alkalinity in the red mud.
Further this neutralized red mud was thermally activated called activated neutralized red mud (ANRM) and another novel adsorbent called red mud modified by lanthanum (La-ARM); prepared by red mud and rare earth element lanthanum was used as a low cost adsorbent for the removal of As (V) from aqueous solution. In the present work a laboratory study was conducted to know the removal efficiency of ANRM and La-ARM for the removal of As (V) from the aqueous solutions by batch method. The experiment was conducted as a function of adsorbent dose, pH, contact time, temperature, initial As (V) concentration, kinetics, thermodynamic and isotherms. The characterization of ANRM and La-ARM before and after adsorption was studied by help of instrumental technique like XRD, SEM-EDX, FT-IR, TG-DTA and chemical methods. Adsorption study was carried out with the initial concentration of 5 mg/L, 10 mg/L and 20 mg/L of As (V) solution. Adsorption kinetics results showed that both the adsorbent follow the pseudo-second order model. The adsorption data was best fitted to Langmuir isotherm model which suggest the monolayer adsorption pattern. The maximum adsorption capacity for ANRM and La-ARM was found to be 2.16 mg/L and 2.408 mg/L respectively. The thermodynamic study suggests the adsorption was spontaneous and endothermic in nature. The intraparticle diffusion model suggests that intraparticle diffusion is not the sole limiting factor. The regeneration and reusability study was done to know the applicability of the adsorbent material. From the above result both the adsorbent was found as an excellent adsorbent for the removal of As (V) from water. This study demonstrates a method which utilized the industrial waste and converting into a valuable resource.
33
Mohanta, Debashrit. "Determination of Some Bench Blast Parameters Using Voronoi Diagram Concept." Thesis, 2015. http://ethesis.nitrkl.ac.in/7600/1/2015_MT_Determination_Debabrit_mahanta.pdf.
Full textAbstract:
In this twenty-first century surface mining activities contribute around 90% of the mineral production in our country. This milestone is achieved through the deployment of high capacity excavation machineries- earth moving machines, large hole drilling machines, etc. As these machineries involve high investment, effective utilization is a must for higher production. But their performance depends upon the fragmentation size, which in turn depends upon the Blast Design. Thus Blast design contributes a major role in reducing cost and increasing production. Due to varying geological conditions as well as rock properties, there exists multiple approaches for the design of blasting operations. Those suffer from many drawbacks as inaccurate assumptions in rock mass characteristics, rick analysis not included, inadequate data bank, etc. Veronoi design is a new method to calculate and analyze some of the parameters of bench blast. An analytical solution for row and blasthole spacing is first calculated based on explosive charge maximization. Then Voronoi diagram is generated for the blast area utilizing the reference co-ordinates of the blast holes. Charge mass of each blasthole is calculated by volume formula utilizing voronoi diagram. A code is developed for hole-by-hole initiation sequence in Microsoft visual studio considering voronoi concept. The investigation analyses the applicability of the concept in two iron ore mines
34
Mallick, Pratishruti. "Gas Permeability of Coal at In-Situ Conditions." Thesis, 2019. http://ethesis.nitrkl.ac.in/10126/1/2019_MTR_PMallick_615MN1002_Gas.pdf.
Full textAbstract:
Depletion of conventional resources, and increasing demand for clean energy, forces India to hunt for alternatives to conventional energy resources. Intense importance has been given for finding out more and more energy resources; specifically, non-conventional ones like CBM, shale gas and gas hydrates, as gas is less polluting compared to oil or coal. CBM is considered to be one of the most viable alternatives to combat the situation. With growing demand and rising oil and gas prices, CBM is definitely a feasible alternative supplementary energy source.CBM is a remarkably clean fuel if utilized efficiently. Production of CBM is initiated by water depletion method i.e. reduction in pressure in the coal bed as water is being pumped out from the reservoir. Desorption of methane creates voids in the coal matrix which help in the CO2 storage. Commercially, the production of methane depends on proximate and ultimate analyses parameters, petrographic parameters, microstructural analysis, mechanical properties, adsorption characteristics and permeability characteristics of the coal samples. Gas permeability affects the most in the determination of gas flow from the matrix to well and vice versa and is usually affected by any changes in the mechanical properties. Therefore, it is important to determine these parameters in order to evaluate the changes in the permeability with varying confinement and gas pressures.
In this research work, investigations were carried out to characterize coal properties, adsorption, and gas permeability characteristics of coal from 200 to 690 m depth from Raniganj coalfield. Proximate and ultimate analyses, petrographic analysis, microstructural analysis and mechanical properties have been evaluated for the characterization of the coal bed reservoir. The variation of the proximate analysis parameters with depth like moisture content, volatile matter and ash content confirms coal from medium to low volatile bituminous coal. Reduction in moisture content from 1.95 % to 0.4 % and higher fixed carbon from 50.36 % to 56.72 % with increase in depth from 200 to 690 m confirms higher porosity and gas adsorption sites in coal matrix. Ash content was 22.61 % at 690 m which displays increase in hydrocarbon content with depth. The variation in ultimate analysis parameters like carbon, hydrogen, nitrogen and sulphur confirms the coal samples are bituminous in nature. The variation of carbon and hydrogen content exhibits enrichment of vitrinite macerals and methane generation in the coals seams with depth. Increase in the virtrinite macerals confirms the increase in methane content of coal seam with depth. The calculated vitrinite reflectance ranges from 0.52 % to 0.77 % which lies between the threshold value and thus reflects the commercial prospects of CBM in study area. The FE-SEM images indicate the presence of primary and secondary pores in coal. The distribution of pores was dispersed or aggregated, circular, elliptical and lenticular or strip indicates strong adsorption capacity of hydrocarbons. Inter particle as well as intra particle pores were distributed throughout the coal samples significantly impacting hydrocarbon storage. The presence of micro fractures at the edges confirms the existence of flow channels between micropores and macropores for flow of gas. Unconfined compressive strength, elastic modulus and Poisson’s ratio varied from 2.31 MPa to 5.56 MPa, 0.407 GPa to 0.535 GPa and 0.319 to 0.371.
Maximum storage capacity of 25.85 cc/gm for CO2 and 13.4 cc/gm for CH4 was observed at 690 m. Increase in gas storage with depth is due to reduced moisture content and ash content in coal, resulting in more sites available for gas adsorption. The adsorption capacity of CO2 was higher than that of CH4 because of small molecular size of CO2 as compared to CH4. Higher CO2 adsorption capacity of coal confirms promising CBM potential in Raniganj coalfield. The CO2 permeability varies from 0.92 to 1.72 mD with increase in depth whereas the CH4 permeability varies from 0.48 to 0.96 mD. Permeability reduced rapidly from 1 to 4 MPa. The reduction in permeability is due to crushing of grains as well as narrowing and closure of fracture. The cleat width of coal specimen exhibited 12 to 47 % reduction from 200 to 690 m depth respectively due to gas pressure.
The findings consist characterization of coal samples based on the laboratory experimentation, determination of adsorption capacity of coal and its variation with pressure, variation of permeability with confinement, gas pressure and mean gas pressure, which is useful and needed information for industrial and commercial CBM production.
35
Pradhan, Dhruti Sundar. "Impact of Surface Runoff from Opencast Coal Mines in the Ib Valley Basin and its Management." Thesis, 2016. http://ethesis.nitrkl.ac.in/8475/1/2016_MT_DSPradhan_614MN3001.pdf.
Full textAbstract:
Energy is needed for economic growth,for improving the quality of life and for increasing opportunities for development.Most of energy requirement is fulfilled by coal,accounting for nearly 60% of the commercial energy demand of our country.Nearly 86% of these coals are obtained from opencast coal mines,which occupy very large areas.Opencast coal mining activities are known to cause serious environmental pollution if proper preventive and control measures are not adopted.Contamination of surface water bodies due to surface runoff in monsoon is one such concern.In this work,an attempt has been made to assess the runoff generated during monsoon in the Ib valley basin, which hosts some of the major opencast coal mines of the country.The Ib river valley is endowed with a very rich coal field known as Ib Valley Coalfield,which is a part of large synclinal Gondwana basin of Raigarh-Himgir and Chhattisgarh coalfields,and constitutes the south-eastern extension of the Sone-Mahanadi master basin.There are five opencast coal mines in this basin viz.Lajkura, Samaleswari,Belpahar,Lakhanpur and Lilari OCP, which come under Jharsuguda district in the state of Odisha.During monsoon season,rain water falls in the entire quarry area, external OB dump,coal stock and siding etc.in the entire coal field.The runoff flows into or out of the mine depending upon its topological profile.The surface runoff of the region takes its natural course flowing through the OB dumps,coal stocks,workshops and railway sidings into the surrounding water bodies which finally meet with Ib river. The Ib River flows from north to south and finally drains into Hirakud reservoir.This water often contains high load of total suspended solid(TSS),total dissolved solid(TDS), and heavy metals,which contaminate the surface and ground water.Sometimes it is acidic in nature and pollutes the water regime if the coal seam contains high amount of pyritic deposit.Therefore,the quantification of surface runoff from the coalfield and the study of its impact are very significant in order to formulate an appropriate management strategy.The present work deals with estimation of the runoff quantity during the monsoon season in a GIS interface.The surface runoff generated within the mine area and the sump capacity has been estimated by rational method.Visual interpretation of the DEM and flow direction maps generated in a GIS interface has helped us in understanding the behavior and direction of surface runoff because of the region’s topography.It was found that Lajkura and Samleswari OCP have adequate sump capacity to store the surface runoff generated during the monsoon. However,the other opencast projects do not have the storage capability to store the surface runoff within the mine premises.These mines need to create additional sumps; otherwise,sedimentation ponds of adequate dimension are required so that the suspended particles could be settled before the runoff is discharged to outside the mine boundary.
Additionally, water quality analysis was carried out to ascertain the quality of water within the mines as well as in the nearby areas. A number of water samples were collected from mine sumps, treatment plant inlet and outlet, mine discharges and nearby water bodies for the pre-monsoon and monsoon period. Analysis for Physical, chemical parameters and heavy metal content was carried out following the standard method given in APHA, 2012 and as per the CPCB guidelines. In general, the water quality of mine sump in most of the opencast mines are found to be within permissible limit for utilization in industrial activities like dust suppression, firefighting, irrigation of plantation, washing of HEMMs etc. It has been observed that there is increase in concentration of parameters like TSS, Oil and Grease in water samples collected in the monsoon season compared to the premonsoon quality. Most of the mine sump water is nearly neutral to alkaline in nature. However, the mine water of Lajkiura sump and Samaleswari south sump show strongly acidic characteristics. In most of the samples, the heavy metal concentrations are within the permissible limit as compared to effluent standards prescribed under Environment Protection Rules, 1986. But high concentration of selenium has been observed in some of the water samples, which have several health impacts on the human beings, animals as well as aquatic life. It is expected that the outcome of the study will help the mine management to formulate an appropriate strategy for control of surface runoff generated during the monsoon. This will help to avoid the surface runoff being discharged to the nearby areas and their probable contamination. Moreover, there is huge water demand in the mining area to fulfill the daily requirement during non-monsoon period. Thus, with adoption of proper management strategy, the runoff generated during the monsoon could be stored within the mine premises and used throughout the year. The water could also be supplied to nearby areas for irrigation of agricultural land in the dry seasons. If possible, it can even be used to supplement drinking water with some treatment.
36
Ragam, Prashanth. "Development of IoT-Based Real-Time Monitoring System and Prediction of Blast-Induced Ground Vibrations in Opencast Mines using Soft Computing Techniques." Thesis, 2020. http://ethesis.nitrkl.ac.in/10193/1/2020_PhD_PRagam_514MN1004_Development.pdf.
Full textAbstract:
Blasting is an economical and viable operation for reliable excavation of hard rock in mining and civil construction. An ambiguous ground vibration generated by blasting is unenviable and causes grievous damage to nearby inhabitants, residential premises, and other sensitive sites. Consequently, proper monitoring and prediction of ambiguous ground vibration is an indispensable prerequisite to pinpoint the safe limits in and around mines to reduce their hazardous effects. Currently, conventional monitoring systems (seismographs) are widely used to measure the ground vibrations purposes. The existing systems have few limitations such as expensive, need an expert to operate, tedious, and time-consuming process. To mitigate the flaws of existing system, in this work, designed and developed a real-time, economical, reliable, continuous monitoring wireless system with Internet of Things (IoT) technology for blast-induced ground vibration (BIGV) measurement. The recent proliferation of wireless sensor networks (WSNs) evolution into the IoT vision enables a variety of low-cost monitoring applications which allows a seamless transfer of information via embedded computing and network devices. As Micro-Electro-Mechanical-System (MEMS) based accelerometer sensors are becoming widely prevalent in vibration and condition monitoring applications.
Additionally, these sensors are integrated within a wireless sensor network (WSN) to allow monitored data to be transmitted wirelessly. The developed system was integrated with threeaxis, low-g, cost-effective ICM-20600 MEMS accelerometer and 32-bit ATSAMV71N21B microcontroller. In addition, a General Pocket Radio Service (GPRS) for SIM800C device was used as a radio frequency module and integrated to design an effective prototype. The experiment has been carried out by installing IoT prototype at Dungri limestone of ACC Limited, Bargarh, India, and twenty-two blast-events PPV was recorded at variable distances from blast source. The experiment results ensure that the Peak Particle Velocity (PPV) ranges from 0.081 to 2.94 mm/s at different monitoring locations. Similarly, in this study, to evaluate and predict the ambiguous PPV, seven conventional predictor models proposed by the United States Bureau of Mines (USBM), Ambraseys–Hendron, Langefors–Kihlstrom, General predictor, Ghosh–Daemen predictor, Central Mining Research Institute (CMRI) predictor, Bureau of Indian Standards, as well as Multiple Linear Regression (MLR), were applied and established a relation between PPV and its influencing parameters. The results were compared based on evaluation performance models such as Coefficient of Determination (R2), Mean Absolute Deviation (MAD), Root Mean Square Error (RMSE), and Normalized Root Mean Vii Square Error (NRMSE) between monitored and predicted values of PPV. The outcomes of empirical predictors exhibit that the MLR model yields significant R2 (0.86420), MAD (0.24122), NRMSE (0.23539), and less RMSE (0.28940) as compared to other conventional predictor equations. Although, empirical predictor models have two major flaws such as lack of generalizability and a limited number of input variables. Therefore, a study on the development of an alternative method of accurate PPV prediction using soft computing techniques was undertaken. An endeavor has been made in this research to apply three soft computing prediction models, namely, Feed-Forward Back Propagation Multilayer Perception (MLP) Neural Network, Radial Basis Function Neural Network (RBFNN), and Support Vector Machine (SVM). In this context, eleven input parameters such as number of holes, average top stemming, average spacing, average burden, average hole depth, hole diameter, maximum charge per delay, powder factor, total explosive, total depth, as well as absolute distance, and one output: PPV, was used and trained. The obtained results reveal that the RBFNN approach provides high R2 (0.99891), Accuracy (99.62956), MAD (0.00370), NRMSE (0.02287), and low RMSE (0.04897) among all other soft computing techniques and empirical predictor approaches for accurate prediction of blast-induced ground vibration. Hence, the RBFNN model yielded better performance as compared to the other prediction models to estimate the PPV.
37
Pradhan, Samresh Kumar. "A Neural Network Approach for the Prediction of Ground Vibrations Induced Due to Blasting." Thesis, 2016. http://ethesis.nitrkl.ac.in/8090/1/2016_M_Tech_711MN1145_A_Neural.pdf.
Full textAbstract:
This project presents the application of neural networks as well as statistical techniques for prediction of ground vibration by major influencing parameters of blast design. The predictions by artificial neural network (ANN) is compared with the predictions of conventional statistical relation. Ground vibrations and frequency induced due to blasting were monitored at Indian Detonators Limited Rourkela (IDL), Balphimali Bauxite mine (UAIL) and Dunguri Limestone mine (ACC). The neural network was trained by the data sets recorded at the various mine sites. From the analysis it was observed that the correlation coefficient determined for PPV and frequency by ANN was higher than the correlation coefficient of statistical analysis. The correlation coefficient determined for PPV and frequency by ANN for Balphimali Bauxite mine (UAIL) was 0.9563 and 0.9721 respectively and correlation coefficient determined for PPV and frequency by ANN for IDL was 0.9053 and 0.9136 while correlation coefficient determined for PPV and frequency by ANN for Dunguri Limestone mine (ACC) was 0.9322 and 0.9301. The difference in correlation coefficient of PPV and frequency in different mines is due to different number of input parameters for the neural network and number of datasets used for the training of network. The number of datasets and input parameters were more for Balphimali Bauxite mine (UAIL), thus it showed higher correlation coefficient between the recorded and predicted data by ANN than other mines.
38
Dreyßig, Julia [Verfasser]. "Surface marker expression profiles of dendritic cells (DC) generated from blasts in patients with acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) are valuable tools to characterize and quantify DC in experimental settings / vorgelegt von Julia Dreyßig." 2010. http://d-nb.info/1005352291/34.
Full text
39
Badal, K. Kujur. "Blast Vibration Studies in Surface Mines." Thesis, 2010. http://ethesis.nitrkl.ac.in/1788/1/THESIS-BADAL_KUMAR_KUJUR-10605005BLAST_VIBRATION_STUDIES_IN_SURFACE_MINES.pdf.
Full textAbstract:
Blasting is very important process for mining operation and a lot of explosive is used for this purpose. The blasting process and usage of explosives, however, remain a potential source of numerous human and environmental hazards. Various studies indicate that fragmentation accounts for only 20-30% of the total amount of explosive energy used. Rest of the energy is lost in the form of ground vibration, fly rock, air overpressure and noise. The specific problem associated with ground vibrations represents the human response to them. Blasting vibrations may also cause a significant damage to nearby buildings or various structures. In this project blast vibration study is done and it is interpreted for its effects in reference to the standards set by DGMS.
The study has been done with the help of geophones and Blastmate8.0 software. First of all the blasting operations were monitored through geophones at distances of 100m, 200m and 300m. The data obtained from the instrument were interpreted by Blastmate software and the graphical output was obtained from it. The Peak Particle Velocity (PPV), maximum charge per delay, air over pressure was recorded for each blast. After that the various observations were compared with the standards to determine the conclusion.
From the analysis of blasts vibration at the mines it was determined that the vibration level was less than 5 mm/sec for the blasts when recommended amount of charge per delay or safe charge per delay was used. The air overpressure value determined was in between 114 & 127.6 dB (L).
The results determined from the project indicates that the peak particle velocity, air overpressure generated due to blasting were within the limits. The safe charge per delay for the blasting operation was determined from the study.
40
Clayton, DK. "Blast survivability of a fatigued naval surface platform." Thesis, 2022. https://eprints.utas.edu.au/47501/1/Clayton_whole_thesis_ex_pub_mat.pdf.
Full textAbstract:
An assessment of the blast survivability is a requirement of modern naval vessels during both the initial design stage, and when life-of-type extension analyses are undertaken. Changes in the operational profile of naval vessels throughout their service life combined with the use of high strength maritime steels have resulted in structural fatigue becoming an increasingly important consideration as vessels age. Literature suggests that fatigue ageing may impact the high strain-rate performance of a structure. A lack of understanding of the effects of fatigue aging may therefore result in overestimations of the blast survivability of a naval platform, possibly putting sailors’ lives at a greater risk than if the effects could be accounted for.
This PhD thesis aims to investigate and quantify the effect that fatigue has on blast survivability of naval structures made of DH36 steel, a common naval structural steel, by means of experimental and numerical investigations. The experimental methodology was developed and implemented to determine any effect of fatigue ageing on the high strain rate material properties of DH36. The numerical investigation determined the effect of fatigue cracking on structural response to blast loading. Following this, two machine learning tools were developed to enable the consideration of the results of this research in the design and analysis of a vessel.
The novel experimental methodology included the development of a fatigue ageing process for DH-36 specimens from which smaller specimens for high strain rate testing were obtained. These smaller specimens were tested using a bespoke Split Hopkinson Tension Bar setup. The results show that there is no significant change in the high strain rate material properties of fatigued DH36, however a reduction in quasi-static yield stress and flow stress curves is evident.
The numerical investigation was aimed at determining the effects that fatigue cracks may have on the structural response of a representative ship stiffened panel. The novel methodology includes extensive validation of an application of crack propagation elements in LS-DYNA using experimentally obtained explosive bulge tests data. The inbuilt LS-DYNA Friedlander-equation-based load models are utilised to model the blast loading over a wide range of charge sizes, stand-offs, and locations for a variety of crack lengths determined by crack propagation modelling. It was found that, for the investigated stiffened panel, a reduction in the highest survivable charge size of up to 37.5% exists, when compared to the survivable charge size for a crack that is not detectable by eye. This finding suggests that cracks can play a significant role in the structural response to blast loading for ship stiffened panels. The finding displays a need for designers and analysts to account for the effect of cracks on blast survivability.
To assist the design and analysis of the fatigue effect on blast survivability a machine learning tool was developed based on a Neural Network algorithm. The tool allows for the rapid assessment of the charge required to initiate plate failure of a representative stiffened ship panel and is based on inputs of the charge size and location, and the length of fatigue crack that is present in the stiffener. The tool can readily integrate new or extended datasets of blast event results, and once an appropriate dataset is used for training, allows designers to determine the effect of different fatigue crack scenarios on the survivability of a given geometry when a fatigue analysis is incorporated.
Finally, a method to determine the blast survivability of a representative ship stiffened panel is presented. The methodology utilises the results of the numerical investigation into blast loading and fatigue cracks, alongside crack initiation and growth models to determine change in blast survivability over time. The blast survivability of a representative ship stiffened panel is suggested to have been reduced by an average of 9% over a 20-year period due to fatigue crack growth. This is a significant reduction which, if unaccounted for in design and life-of-type extension analyses, will lead to the overestimation of the ability of a vessel to withstand blast loading.
41
Lin, Yu-Lin, and 林佑霖. "Tribological Performance of EPDM Wiper Blades with Surface Coating." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/58auxt.
Full textAbstract:
碩士國立宜蘭大學
機械與機電工程學系碩士班
105
The rubber properties of automobile wiper blades have a direct impact on their resistance to weathering and tribological performance. Ethylene propylene diene monomer (EPDM) rubber has good chemical stability and weatherability. However, its friction coefficient on glass is relatively high, and the frequently-used friction reducing methods of wiper blades, e.g. graphite-coating and halogenation treatments, are not applicable due to the low surface energy and good chemical stability of EPDM. Because of the friction problems, EPDM wiper blades are barely commercialized so far. This study tried to use plasma to activate the surface of EPDM wiper blades, followed by the deposition of graphite or friction reducer. Plasma parameters were tuned followed by coating graphite or friction reducer to improve the tribological behaviors of EPDM wiper blades on glass. In particular, the variations of friction coefficients of these wiper blades with wiping cycles were investigated during 800,000 reciprocating sweeps, and the morphology of worn surfaces were examined by microscope. The results show that plasma treatments can significantly enhance the adhesion of graphite or friction reducer to EPDM wiper blades, and the reduction in the friction coefficient is as high as 50%. As to plasma process parameters, a low scanning speed helps to fully activate the wiper blades and thus to reduce the friction coefficient. The optimal process parameters are 500 W in plasma power and 83 mm/s in plasma scanning speed. Overall, the friction reducer is a better deposition material than graphite, especially in the stabilization of friction coefficient and in the reduction of wear. Employing the optimal process parameters in the plasma treatment followed by the deposition of graphite or friction reducer, the friction coefficient of EPDM wiper blades can be reduced to a level close to that of current mainstream material of wiper products - chlorinated natural rubber. In addition to improving the weatherability of wiper blades, the traditional chemical chlorination treatments can be skipped, and the costs and pollutions can thus be reduced. Consequently, the process developed in this study has a market advantage and contributes to environmental protection.
42
Lai, Ying-Hui, and 賴&;#63918;徽. "The Study of the Coating Surface of Gas TurbineCompressor Blades." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/61125816798210896140.
Full textAbstract:
碩士中興大學
材料科學與工程學系所
102
In this study, the inorganic coating and atmospheric plasma spray (APS) coating were applied to the SUS420J2 stainless steel which was the material of gas turbine compressor blades. The results showed that the inorganic coating consisted of the AlPO4, Cr2O3 and pure Al after the coating being heated, and the APS coating consisted of the γ-(Ni,Co,Cr) phase. Microstructural observation showed that, in the inorganic coating, the pure Al was surrounded by the AlPO4 and Cr2O3 and formed a compact coating without voids; the APS coating was loose and contained voids, oxides and un-melted powders. The thickness of the inorganic coating and the APS coating was 25~45μm and 75~125μm,respectively. The surface roughness of the inorganic coating was Ra 0.7μm and was lower than that of the APS coating, which was over Ra 40 μm. The abrasion test revealed that the inorganic coating and the APS coating had abrasion resistance ratio 73 and 41,respectively. Both of these two coatings were classified as the abrasion-resistant coating. Comparing these results, it could be concluded that the inorganic coating was suitable for the compressor blades. After the inorganic coated blade was applied to the compressor for 78,932 hours, the coating thickness remained 5 μm. The coated blade had no sign of pitting, stains or erosions. It could be concluded that the inorganic coating could protect the blade and extend the blade lifetime.
43
Lai, Ying-Hui, and 賴瑩徽. "The Study of the Coating Surface of Gas TurbineCompressor Blades." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/81203596132613106474.
Full textAbstract:
碩士國立中興大學
材料科學與工程學系所
102
In this study, the inorganic coating and atmospheric plasma spray (APS) coating were applied to the SUS420J2 stainless steel which was the material of gas turbine compressor blades. The results showed that the inorganic coating consisted of the AlPO4, Cr2O3 and pure Al after the coating being heated, and the APS coating consisted of the γ-(Ni,Co,Cr) phase. Microstructural observation showed that, in the inorganic coating, the pure Al was surrounded by the AlPO4 and Cr2O3 and formed a compact coating without voids; the APS coating was loose and contained voids, oxides and un-melted powders. The thickness of the inorganic coating and the APS coating was 25~45μm and 75~125μm,respectively. The surface roughness of the inorganic coating was Ra 0.7μm and was lower than that of the APS coating, which was over Ra 40 μm. The abrasion test revealed that the inorganic coating and the APS coating had abrasion resistance ratio 73 and 41,respectively. Both of these two coatings were classified as the abrasion-resistant coating. Comparing these results, it could be concluded that the inorganic coating was suitable for the compressor blades. After the inorganic coated blade was applied to the compressor for 78,932 hours, the coating thickness remained 5 μm. The coated blade had no sign of pitting, stains or erosions. It could be concluded that the inorganic coating could protect the blade and extend the blade lifetime.
44
Wu, Tian-Cheng, and 吳添成. "The research of surface tension and liquid temperature of blast furnace slags contain sulfur." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/52632735618307991421.
Full textAbstract:
碩士國立臺灣大學
材料科學與工程學研究所
101
Sulfur content of steel can be reduced to a lower level with a low content of hot metal, which can be implanted by employing the magnesium injection process in the blast furnace to have an efficient desulfurization of the liquid iron. However, the slag surface tension and viscosity change with the increase of MgS content of desulfurization product. In this thesis, the melting temperature and surface tension of FetO-SiO2-CaO-MgO-Al2O3-TiO2-MnO-MgS slag with different composition including magnesium sulfide will be first evaluated with the sessile drop contact angle method. The viscosity is then predicted by using the optical basicity ratio model. Furthermore, by applying Pelofsky equation, the surface tension could be calculated with the viscosity values. Finally, the experimental surface tension is correlated with measured values.
45
Liu, Shu-Ming, and 劉樹明. "The Enhancement of Surface Area of Coal Fly Ash /Iron Blast Furnace Slag by Organic Acid." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/74851526494634188848.
Full textAbstract:
碩士國立屏東科技大學
環境工程與科學系
92
The purpose of this study is to modify Coal Fly Ash (CFA) / Iron Blast Furnace Slag (IBFS) into an absorbent for heavy metal or (in) organic pollutants, by change its recipes and synthesis conditions in order to investigate an optima operation mode for increasing its adsorptive ability. The materials used for this study are CFA from steam power plant and IBFS form China Steel Corp. Either CFA or IBFS contains high amount glassy content of CaO, SiO2 and Al2O3. There are approximate 70 wt% glassy content in CFA, and 95 wt% in IBFS. These Kinds glassy are like nature Pozzolana which are easy to hydrate with Ca(OH)2 solution to form a series of calcium silicate hydrates or calcium aluminate hydrates with large surface area and somewhat mechanical strength. The hydrates are amorphous gels, and possess fiber texture. This study try to use the characteristic of the fiber texture to change its structure into a larger surface area structure by using the addition of organic acids which are Citric acid, Lactic acid and Acetic acid. The procedures in sequence are, 1) to mix CFA/IBFS with Ca(OH)2 and water. 2) to add different concentration of each acid individually. 3) to stir together and at the same time heat the sample from ambient temperature to 70, 80 or 90ºC. 4) to put each sample at a fixed temperature as former an a fixed period. 5) to filter and to dry the synthesized produces. 6) to measure specific surface area of dry produces by air permeability apparatus.The results indicate that, (1)The surface area of without acid is less than those of with acid and the highest surface area is the sample with citric acid.(2)The optima temperature is with Citric Acid at 80ºC, with Lactic Acid at 90ºC, and with Acetic acid at 70ºC.(3)the optima recipes is CFA / IBFS = 3/7 for any kind of acid. Many researcher have reported that it is a technique whatever Bench-Test or Pilot-Scale-Test by utilizing CFA to synthesis an absorbent for the adsorption of SOx from flue gas or for the adsorption of heavy metal from waste water. The success of this study could provide an another choice on the selection of adsorbent, and an another recycling method to promote the additional value of waste utilization.
46
ZHI-XIANGHUANG and 黃志翔. "Application of Image Segmentation Method to Surface Peeling Damage of Wind Turbine Blades." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/4vxyt7.
Full text
47
LIN, DAI-HUA, and 林岱樺. "The Analysis on the Failure Mode of the Sand Blast Process with Surface Roughness via FMEA and Fuzzy." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/455k46.
Full textAbstract:
碩士正修科技大學
工業工程與管理研究所
107
The sandblasting process is a commonly used metal pretreatment process in the industry. The wind blows a lighter weight material or uses a power blade to drive a heavier specific substance to hit the surface of the object to be treated. Frequently in the process, the problem is that the actual surface of the blasting surface is flawed, the color difference or even the surface roughness is not in conformity with the customer's requirements, resulting in the whole batch of inspection or resignation after the shipment to the client or the actual quality of the personnel to the customer's factory. The re-testing has led to an increase in the company's production waste, while internal and external costs have increased, while profits have also decreased. In the aerospace industry, the completeness of the product's functionality is very important. Once the product process fails, not only the customer has doubts about the product quality, but also loses confidence, which indirectly affects the company's reliability, which in turn affects the customer's commitment to the product. The willingness of the company. Failure Mode & Effects Analysis(FMEA)is a preventive reliability engineering technology that assists engineers in identifying potential risks in design or process at the beginning of product development, so that precautions can be taken early to improve the product. Reliability. Therefore, it is often used in the product design stage or in the analysis of the improvement and safety of the process. Therefore, by discussing the inspection process of the production quality of aerospace components, the risk management mechanism is established, and the failure mode and effect analysis methods in the reliability engineering are brought into the sandblasting process to find the potential failure causes, and the potential failure causes. Calculate the severity rating criteria by calculating the Cp index converted to process capability through actual measurement data, and calculate the individual process risk priority values according to factors such as detectability and occurrence, except that the priority value is prioritized according to the risk priority value. In order to improve the program, the fuzzy theory is used to analyze the model and defuzzify to get the best risk priority data. After identifying the priority of the failure mode risk, and based on the current control method, study the detection method of the simulated failure and seek remedial measures as a reference for action to prevent failure or improve the process.
48
Lo, Fang-Chun, and 羅芳鈞. "Application of Short-Time Fourier Transform for Real-Time Surface Damage Detection of Wind Turbine Blades." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/tgpw7x.
Full textAbstract:
碩士國立臺灣大學
工程科學及海洋工程學研究所
105
The main idea of this research is to establish a complete system for surface damage detection of wind turbine blades. Because of long-term exposure in an extreme environment, the damage on wind turbine’s components is inevitable, and mostly on the blades. Thus, wind turbine requires regular detection and maintenance to avoid safety issues and financial loses. The traditional assessment for surface damage detection of wind turbine blades is to evaluate the operation noise by a professional using his ears to listen. Sometimes, judging by the professional’s personal experience, he has to stop the wind turbine and execute the detection from the above to the blades. Not only does it demand special skills, it is also accompanied with high risk caused by the extreme environment wind turbine was built at. So, it is very dangerous and inconvenient for us if we must count on ears or climbing skills to conduct the assessment, not to mention the recent arising of offshore wind turbine. With the number of global wind turbine rapidly increases and develops, establishing a complete system for surface damage detection of wind turbine blades becomes more and more essential. This research using time-frequency analysis short-time Fourier transform from MATLAB to analyze the blades’ noise while operation, by placing microphone under the wind turbine and recording. First, to build a normal model as foundation for comparison, we put recordings of a wind turbine without abnormal sound into time-frequency analysis and applying it to methods like marginal spectrum, decibel transformation and polynomial regression. Then, based on the normal model, we defined the formula this research shows, as an indicator to determine if the blades are damaged. Finally, we can also define the optimal damage threshold by utilizing the receiver operating characteristic curve and calculating the area under the curve. This new way for detection allows us to receive blades’ damage reports by computer’s automatically diagnosis without affecting or stopping the wind turbine’s operation. This research’s detection results are testified by actual photo from wind turbine’s blades. Hopefully, it can be applied as wind turbine’s health detection systems in the future.
49
Li, Song-Bo, and 李松柏. "Application of Reverse Engineering to Reconstruct and Fabricate Surface of Micro Turbine Blades by Taguchi Method." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/29574547634189263564.
Full textAbstract:
碩士國立雲林科技大學
機械工程系碩士班
95
This thesis aims at application of reverse engineering to reconstruct and fabricate surface of micro turbine blades by Taguchi method, and we use Taguchi method to design the parameter of 3D optical scanner in order to promote the accuracy that the prototype reconstruct. In this research, using the reverse engineering software Geomagic Qualify to do a deviation comparison of scanning result. Also, the experimental design of Taguchi method, the orthogonal array, and the analysis of S/N ratio are utilized to find the best parameter combinations of scanner factor in order to reduce the standard deviation. Application of the reverse engineering software Geomagic Studio to repair and establish surface, and achieving prototype fabrication by rapid prototyping. It expects to obtain micro turbine blades of accuracy by this procedure.
50
Chang, Sheng-Wei, and 張勝惟. "Effect of Sand-blasted, Large grit, Acid-etched Combined Alkaline, Acid, Heat Surface Treatment on Osteointergartion of Dental Implant: Animal study." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/30512257462224516278.
Full textAbstract:
碩士國立臺灣大學
臨床牙醫學研究所
100
Since 1970s, replacement of missing teeth with dental implant has become a popular treatment option in dental treatment. The successful implant depended on the osseointegration between implant and bone which took a period of time for healing. Various surface treatment schemes on dental implant have being developed in order to hasten osseointegration thus shorten the healing time. Surface treatment scheme using sand-blasted, large grit, acid-etched surface treatment (SLA) has been proposed used for a period of time; however, SLA treated implant still need more healing time for osteointergration. Recently, a new surface treatment scheme using alkaline, acid and heat surface treatment (AAH) surface treatment has been proposed. The purpose of this study is to evaluate the effect of two new surface treatments (Sand-blasted ,Large grit, Acid -etched combined Alkaline ,Acid , Heat surface treatment(SLA+AAH)) on osseointegartion. Three different surface treatment implants with two type screw design, one surface treatment is SLA+AAH surface treatment type, the other is SLA (Sand-blasted, Large grit, Acid etched),with same screw design and TiUnite (Nobel Biocare - NP) were compared. Nine beagle dogs were enrolled in this study, divided into 3 groups (4, 8, 12 weeks), six dental implants were inserted in each dog included two experimental groups(SLA+AAH) and two control group(SLA and TiUnite). The assessments of implants are including clinical evaluation, survival rate, resonance frequency test and photo record. Experimental parameters including resonance frequency test(ISQ), bone implant contact (BIC) ,remove torque test were used to analysis the integration of bone and implant. The dogs were sacrificed at the time interval of 4, 8, 12 weeks for further histological analysis. In 8weeks group , implants were placed in tibia for removal torque test. The results showed the value of SLA+AAH surface treatment group in resonance frequency test is slightly higher than SLA group and TiUnite group . It seems that the potential for SLA+AAH chemical modification of the implant surface may possess good biologic events during the osseointegartion process and offer some superiority to implants with the SLA and TiUnite surface. Further study is needed to distinguish the variables for hastening of osseointegartion with modality of new surface treatment.