• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 279
  • 106
  • 60
  • 45
  • 18
  • 14
  • 11
  • 8
  • 7
  • 5
  • 4
  • 4
  • 4
  • 4
  • 3
  • Tagged with
  • 666
  • 65
  • 55
  • 50
  • 50
  • 44
  • 44
  • 42
  • 39
  • 38
  • 38
  • 37
  • 35
  • 34
  • 34
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
331

Geologisk och geokemisk analys av 2 miljarder år gamla stromatoliter och kimberlit/lamprofyr från Kalix / Geological and geochemical analysis of 2 billion year old stromatolites and kimberlite/Lamprophyre from Kalix

Waara, Elin January 2023 (has links)
Den övergripande tanken med projektet är att ta reda på vad som hände på Västra Gräddmanhällan,utanför Kalix kust, för 2 miljarder år sedan. Det görs genom att ta reda på vad det är för bergarter ochstrukturer som hittats på området och hur de korrelerar till varandra. De två huvudsakliga delarna somprojektet fokuserar på är de stromatolitiska strukturerna som finns i de sedimentära bergarterna på VästraGräddmanhällan och de magmatiska intrusionerna som går genom de sedimentära bergarterna. De skaidentifieras med hjälp av tre olika metoder som ska komplettera varandra. Alla tre metoder kräver attprover från platsen hämtas till Uppsala Universitet där de kan slipas ned till tunnslip. Det kommer finnastotalt åtta prover tagna från olika stromatolitiska strukturer, både från land och Västra Gräddmanhällanoch två stycken tunnslip från de magmatiska intrusioner som tidigare antagits vara antingen kimberliteller lamprofyr. Alla tunnslip kommer att studeras i ett optiskt mikroskop och då kommer vissa tunnslipväljas ut för att undersökas i SEM och sedan Elektronmikrosond. Det finns vissa egenskaper i de olikabergarterna som är avgörande för resultatet. I de stromatolitiska strukturerna är spår av paleobiologiviktigt. De saker som kommer att kunna ge en indikation på tidigare liv i en stromatolit är bland annatorganiskt kol och pyrit. Fynd av antingen opaka mineral, organiskt kol eller andra intressanta struktureri det optiska mikroskopet kommer därför påverka projektets gång. För de magmatiska intrusionerna blirdet istället mineralsammansättning och eventuella karbonater som blir viktiga för hur synen på Sverigesgeologiska historia kommer se ut i fortsättningen. / The overall idea of the project is to find out what happened on the Western Gräddmanhällan, off thecoast of Kalix, two billion years ago. This is done by finding out what rocks and structures that are foundin the area and how they correlate to each other. The two parts that this project focuses on is thestromatolitic structures found of the Western Gräddmanhällan and the igneous intrusions that passthrough the sedimentary rocks. They must be identified using three different methods that willcomplement each other. All three methods require samples from the site to be brought to Uppsalauniversity and then be ground down to thinsections. There will be a total of eight thin sections takenfrom different stromatolitic structures, both from the coast and the western Gräddmanhällan and twopieces of thin sections from the magmatic intrusions that are already assumed to be either kimberlite orlamprophyre. All thin sections will be studied in an optic microscope and then certain thin sections willbe selected to be examined in SEM and then Electron Microprobe. There are certain properties in thedifferent rock types that are decisive for the result. In the stromatolitic structures, traces of paleobiologyare important. The things that will be able to give an indication of past life in a stromatolite includeorganic coal and pyrite. Findings of either opaque mineral, organic carbon or other interesting structuresin the optical microscope will therefore affect the progress of the project. For the magmatic intrusions,it will instead be the mineral composition and possible carbonates that will be important for how theview of Sweden's geological history will look in the future.
332

Delineating the geometry of the Central Metasedimentary Belt Boundary Zone of the Grenville Province: Nd isotope evidence of a failed back-arc rift zone between Minden and Bancroft, Ontario

Moretton, Katherine 08 1900 (has links)
<p> The Grenville Province represents the remains of a collisional orogeny ca. 1.2 - 1.0 Ga and contains the Central Metasedimentary Belt (CMB). Generally thought to represent one or more accreted island arcs, the CMB is located between belts of highgrade gneisses and contains a number of identified structural terranes. Neodymium (Nd) model ages of the high-grade gneisses on either side of the CMB yield similar values (~1.5 Ga) while the average model age within the CMB is usually more juvenile (<1.3 Ga). This distinction, along with observations about the geometrical shape of the juvenile zone, has led to the creation of an alternative model for the development of the CMB in the Grenville Province as developed by Dickin and McNutt, (2007). The new model equates the CMB with an ensimatic rift zone with an en echelon morphology consisting of a series of segments with NNE trends, separated by one or more horsts of older crustal rock. The development of the CMB under these conditions implies that restricted access to seawater may have facilitated limestone deposition prior to major biogenic influences, and thus the morphology of the rift is defined in part by the extent of the Grenville marble outcrops. </p> <p> The present study tests this model through the use of 80 new Nd isotope analyses to map the NW boundary of the CMB, known as the Central Metasedimentary Belt Boundary Zone (CMBBZ), west of Bancroft, Ontario. Within this part of the CMBBZ, the age boundary between pre-Grenvillian and juvenile gneisses is relatively sharp (1 - 4 km wide) and this age boundary makes a near 90-degree tum from a NNE trend near Minden to an E-W trend near Haliburton. Two blocks of older material are located within the juvenile terranes of the CMB, which are interpreted as being blocks of older crust rifted from the walls of the older Muskoka domain to the north of the study region. These structures are analogous to similar horsts of older crustal material found in the Afar region of East Africa. Therefore, we suggest that the locus of the CMBBZ was constrained by older structures, representing a transition from the side of a rift zone segment south of Minden, to the truncated end of this rift segment between Haliburton and Bancroft. Hence, the detailed structure of the CMBBZ in this region provides further evidence in support of the rift zone model. </p> / Thesis / Master of Science (MSc)
333

Social and Economic development of Fertile Belt #351 including history, material population, institutional development, periods of depression and methods of relief / Social and Economic development of R.M. of Fertile Belt #351 including history, material population, institutional development, periods of depression and methods of relief

Carlson, Donald January 1934 (has links)
The legibility of the digitized copy is limited due to the quality of the original document. McMaster Digitization Centre, 9 March 2019. / 1. Brief summary of location, topographical, and agricultural features. 2. History. The history of R.M. of Fertile Belt, largely the history of settlement by “colonies”. 1884 – Founding of Round Lake Indian Mission (Presbyterian) by Rev. H. (Dr.) McKay. A short history of the work of this mission. 1886 – Founding of Kaposvar Hungarian Colony by Count Paul Esterhazy under direction of Lord Mount Stephen. C.P.R. and Federal Government co-operating. Grant of 125,000 acres. Location. First settlers from the United States. Reinforcements from Hungary in 1888. 1900 – Stockholm Hungarian colony daughter colony of Kaposvar. 1888 – Settlement of Bohemian, Slovak and other Slavonic elements in district north of Kaposvar. First settlers from mines of Pennsylvania. Bulk of settlers after 1900 from Austria and Poland. 1886 – July 1st – Founding of New Stockholm Scandinavian colony on the north bank of Qu’Appelle River above Round Lake. P.O. “Ohren”, founded in 1889. Building of the C.P.R. Kirkella-Saskatoon branch through Fertile Belt in 1902, also G.T.P. through the same area ten miles north in 1907. The significance of these roads and the consequent settlement and development. 3. Material Population Present status of the main national groups: Hungarian, Bohemian-Slavonic, and Scandinavian. Population of Fertile Belt and approximate numbers of each. Social life in early days of the colonies. The place of the church in community life. Traditions and customs of the old land transferred to the new. History and influence of churches in Fertile Belt. Church leaders as immigration and colonization agents for railroads and governments. Assimilation. The use of the Continental and English languages. The problem of the second generation, Education. Inter-marriage. 4. Institutional Development. Churches and schools. From Local Improvement District to Rural Municipality. Farm organizations. 5. Periods of Depression and Methods of Relief. Difficulties of early settlement including: Drought of 1891-92. Low prices of agricultural products and their relation to other commodities. Long distance to markets. The period centering on 1906-07, with some statistics relating to prices of farm products. Period following The Great War. Review of Loan, Mortgage and Debt situation which developed chiefly in and during the five years following the War. Approximate numbers of farmers involved. Possibilities of recuperation. Three dry years, 1929-30-31. Average yields. Summer 1931 R.M. Fertile Belt included in Provincial Relief area. Taxes, the mill rate, methods of collection. School taxes, difficulties of keeping schools in operation, low rates of teachers’ salaries. The compulsory tax collection act of 1932 passed by the Provincial House. The forced return to the farm and the community as an economic unit. The greater emphasis on mixed farming. The “Bennett” wagon, the spinning wheel, and home grown “coffee”. Depression psychology, including attitude to creditors. Some remarks on the depression as it affects the standard of living, education, morals and the opportunities of the rising generation. Effects of depression on the social and religious life of the community. Inclusion of R.M. Fertile Belt in Provincial Relief Area, “C” division, August 1931. (1) Direct Relief: Red Cross operating through municipal office. Notes in payment for clothing. Direct relief given by municipality in form of orders on local stores. (2) Indirect Relief: Road work paid for by orders on local stores, a public work program supported jointly by province and municipality. Road work in payment for taxes, a municipal project. Construction of Highway No. 9 through R.M. of Fertile Belt. A provincial relief project, the farmer working under government contractor. Payment in cash. General comments on the efficiency, utility, and feasibility of the above projects. (3) Feed Relief. Price. Quality. Terms of repayment. Amounts of hay and grain distributed. Administration. (4) Seed Relief. Price. Quality. Amounts. Terms of repayment. Administration. / Thesis / Master of Arts (MA)
334

Characterization of Cu-mineralized carbonate veins in the Alta-Kvænangen Tectonic Window, Norway

Svens, Ellen January 2024 (has links)
The Alta-Kvænangen Tectonic Window is part of a regional greenstone belt that formed around 2.3 Ga – 2.0 Ga. The Bergmark anticline in the area has gone through greenschist to amphibolite facies metamorphism and hosts Cu, Co and Au mineralizations in hydrothermal veins, albite felsite and chemical traps. The area was mined during the late 19th century mostly in trenches but it has still got exploration potential. This project will classify carbonate veins that are hosted within two gabbro units, compare orientations between the barren and mineralized veins as well as discuss the origin of the veins.  The study area has been affected by multiple extensional and compressional events during the Svecokarelian orogeny (1.9 – 1.8 Ga) and regional hydrothermal alterations including an influx of Na + Ca ± K ± Fe. Major shear zones were activated and used for transporting fluids which are thought to have controlled the formation of mineralization in second- or even third-order structures. The veins were studied using field work, detailed mapping, optical microscopy as well as scanning electron microscopy (SEM) and structural analysis. Results gave three different types of hydrothermal veins: 1) Fe oxide veins, 2) calcite veins and 3) dolomite-plagioclase-quartz veins. All of them show strong signs of deformation and recrystallization all while the chalcopyrite mineralization is heterogeneously distributed and commonly more or less bornite-altered. The veins pinch and swell over short distances and are sinuous but with a general orientation. Albite haloes are common for the veins but far from all veins have haloes. There are at least two generations of veins as some were found to have offset others. Brecciation, tension gashes and faults are also found in the area apart from veins. From the field measurements, two groups of orientations could be determined: one with a SW-NE direction and the other in NW-SE direction, both with relatively steep dips. Considering all downhole measurements, no conclusive results could be revealed, however, the optical televiewer results showed that the area has gone through a N-S compression giving a fold axis towards the west. In the end the orientations of the larger veins were found to either run parallel to the gabbro units or are connected to the NW-SE directed main brittle faulting in the Fennoscandian Shield. Smaller, surrounding veins having more diverse orientations. There are multiple signs of deformation and recrystallization in the mafic host rock but no fabric development can be seen. Its appearance varies locally depending on which alterations are dominating. It exhibits sodic-calcic, potassic and leucoxene alteration as well as albitization and carbonatization. The grain size varies from fine-grained to medium-grained which is more typical with a dolerite or basalt, even though it has been previously mapped as a gabbro. No pyroxene was found in the host rock and the plagioclase was Na-rich instead of the expected Ca-rich.  The Bergmark anticline has multiple similarities with the Gällivare-Kiruna area in Sweden which include 1) high-temperature, low-pressure metamorphism resulting in regional alterations such as albitization, carbonatization, amphibole and magnetite alteration. 2) The mineralization consists of Cu, Co, Au, Fe and minor P. 3) The mineralization can be found disseminated in albite felsite, in chemical traps and in first to third order structures (e.g., faults or hydrothermal veins) in brittle, deformed rocks. 4) The mineralization is structurally controlled to the vicinity of major fault zones. 5) In both places, greenstone belts are important for the formation of mineralization. 6) Reactivation of brittle structures, similar to those in the Kiruna area during the second phase of subduction during the Svecokarelian orogeny (D2), is likely the cause for the veining in the Bergmark anticline. 7) A younger N-S compression is recorded in the area. Differences between the Bergmark anticline and the Gällivare-Kiruna area include the lack of intrusions in the vicinity to the Bergmark anticline.
335

Averting Security Threats Through Coup d'états? : Identifying the justifications of the two coups of Burkina Faso in 2022 and the presence of securitization.

Wiking, Samuel January 2024 (has links)
No description available.
336

Scale-up of Using Novel Dewatering Aids

Eraydin, Mert Kerem 23 June 2009 (has links)
Coal preparation plants use large quantities of water for cleaning processes. Upon cleaning, the spent water must be removed such that the final product moisture level meets market constraints. However, removal of free water from the surface of fine particles is difficult and costly, and often the results are less than desirable. Fine particles inherently have very large surface areas, and hence retain large amounts of water. Increased amounts of fines also cause denser particle packing, which creates relatively small capillaries in filter cakes and, thus, cause slower dewatering kinetics. As a result, dewatering costs for fine particles are much higher than for dewatering coarse particles. Considering the technical and economic issues associated with dewatering coal and mineral fines, an extensive matrix of laboratory- and pilot-scale dewatering tests have been conducted to evaluate the use of novel dewatering aids. The reagents are designed to lower the surface tension of water, increase the hydrophobicity of the particles to be dewatered, and increase the capillary radius by hydrophobic coagulation. All of these are designed to lower the moisture of the filter cakes produced in mechanical dewatering processes. Laboratory-scale dewatering tests confirmed that using the novel dewatering aids can lower the final cake moisture of coal by 20-50%, while increasing the dewatering kinetics. Several on-site, pilot-scale tests were conducted to demonstrate that the process of using the novel dewatering aids can be scaled. Based on the laboratory- and pilot-scale tests conducted, a scale-up model for the process of using the novel dewatering aids has been developed. It can predict the final cake moistures as a function of vacuum pressure, filtration time and specific cake weight. The model can be useful for the scale-up of vacuum disc filters (VDF) and horizontal belt filters (HBF). Simulation results indicate that dewatering aids can be very effective, especially when used in conjunction with HBF due to its ability to control cake thickness and drying cycle time independently. In light of the promising laboratory- and pilot-scale test results, an industrial demonstration of the novel dewatering aids has been conducted at the Smith Branch impoundment site, which contains 2.9 million tons of recoverable coal. When the reagent was used for dewatering flotation products using a VDF, the moisture content was reduced from 26 to 20% at 0.5 lb/ton of reagent addition and to 17.5% at 1 lb/ton. The use of the dewatering aid also improved the kinetics of dewatering, increased the throughput, and reduced the power consumption of vacuum pumps by 30%. The novel dewatering aids were also tested successfully for dewatering of kaolin clays. In this case, the mineral was treated with a cationic surfactant before adding the dewatering aids. This two-step hydrophobization process was able to reduce the cake moisture and also increase the throughput. / Ph. D.
337

An Interactive Digital Manual For Safety Around Conveyor Belts In Surface Mining

Worlikar, Poonam 09 July 2008 (has links)
Belt conveyor accidents are mainly attributed to negligence of safety procedures during maintenance work. Entanglement, falling from heights, & collapse of structure or loose materials are the main cause of accidents. While performing maintenance tasks such as cleaning, installation and repair, belt alignment and so on (Lucas et. al. 2007). Current industry safety programs provide general guidelines for safety training, but do not require any specific training program structure (Shultz, 2002 and Shultz, 2003). For example MSHA (Mine Safety and Health Administration) only requires 24 hours of training. Typically this training is broken down into four hours of training before the employee starts work, the remaining 20 hours has to be performed within the first sixty days of work (Goldbeck, 2003). The information collected through site visits showed that in addition to completing MSHA safety training requirements companies try to reinforce safety issues through daily and weekly safety meetings on job sites. Due to lack of a required safety training structure, every company is independent in terms of their training format that they follow to train their new and experienced work force. As a result, safety engineers depend heavily on in-house safety programs (e.g. audio-video presentations) to deliver the required training hours specified by MSHA for miners. Based on a review of current training methods this research identifies four problems; existing training methods to educate miners about dangers involved in conveyor belt environments are mainly passive, safety related information in scattered in various media such as images, videos, paper manuals, etc., access to information in current format is difficult, and updating information is difficult. This research addressed these identified problems by devising a new approach of learning to augment existing methods of training and evaluate the potential of this concept as a safety-training tool. Research has shown that individuals have their own learning style in which they can increase their retention and stimulate their cognitive learning. The proposed work addresses issues relative to passive vs. active learning and classroom-based vs. self-paced training by developing and implementing an interactive multimedia-based safety-training tool called the Digital Safety Manual (DSM). After the DSM was developed it was put through a series of usability evaluation and subjective analysis to measure the potential of the concept. The evaluation and subjective analysis involved both the novice and expert users. The results that were yield after the evaluations and subjective analysis shows that the DSM has more learning advantages than the typical training methods and it can be used as a supplementary training method to complement the current approaches of training. / Master of Science
338

The Potential of Event Data Recorders to Improve Impact Injury Assessment in Real World Crashes

Tsoi, Ada 01 July 2015 (has links)
Event data recorders (EDRs) are an invaluable data source that have begun to, and will increasingly, provide novel insight into motor vehicle crash characteristics. The "black boxes" in automobiles, EDRs directly measure precrash and crash kinematics. This data has the potential to eclipse the many traditional surrogate measures used in vehicle safety that often rely upon assumptions and simplifications of real world crashes. Although EDRs have been equipped in passenger vehicles for over two decades, the recent establishment of regulation has greatly affected the quantity, resolution, duration, and accuracy of the recorded data elements. Thus, there was not only a demand to reestablish confidence in the data, but a need to demonstrate the potential of the data. The objectives of the research presented in this dissertation were to (1) validate EDR data accuracy in full-frontal, side-impact moving deformable barrier, and small overlap crash tests; (2) evaluate EDR survivability beyond regulatory crash tests, (3) determine the seat belt accuracy of current databases, and (4) assess the merits of other vehicle-based crash severity metrics relative to delta-v. This dissertation firstly assessed the capabilities of EDRs. Chapter 2 demonstrated the accuracy of 176 crash tests, corresponding to 29 module types, 5 model years, 9 manufacturers, and 4 testing configurations from 2 regulatory agencies. Beyond accuracy, Chapter 3 established that EDRs are anecdotally capable of surviving extreme events of vehicle fire, vehicle immersion, and high delta; although the frequency of these events are very rare on U.S. highways. The studies in Chapters 4 and 5 evaluated specific applications intended to showcase the potential of EDR data. Even single value data elements from EDRs were shown to be advantageous. In particular, the seat belt use status may become a useful tool to supplement crash investigators, especially in low severity crashes that provide little forensic evidence. Moreover, time-series data from EDRs broadens the number of available vehicle-based crash severity metrics that can be utilized. In particular, EDR data was used to calculate vehicle pulse index (VPI), which was shown to have modestly increased predictive abilities of serious injury compared to the widely used delta-v among belted occupants. Ultimately, this work has strong implications for EDR users, regulatory agencies, and future technologies. / Ph. D.
339

Introduction of grand solar belt of America : combinatorial optimization using genetic algorithms

Miguez, Roberto; 01 January 2009 (has links)
The world has an imperative need to switch to clean and renewable energy sources. Effectively harnessing the vast energy that radiates on the earth's surface from the sun is a long standing goal of clean energy proponents. This work introduces the novel concept of a solar energy belt stretched across America. The thesis provides the first steps towards showing that not only can such a belt be built, but it can effectively yield a substantial quantity of America's energy in a cost effective fashion. In order to maximize impact of the work, a general mathematical model is first derived that may be extended by any interested party. The model is then viewed from the perspective of mathematical combinatorics and is thus made subject to combinatorial optimization. Genetic Algorithms are used for this optimization scheme. A GUI and simulation is provided that demonstrates the evolution of the solar belt solution in real-time. Results are demonstrated.
340

The belt and road initiative (BRI): A mechanism to achieve the ninth sustainable development goal (SDG)

Senadjki, A., Awal, I.M., Nee, A.Y.H., Ogbeibu, Samuel 05 September 2022 (has links)
Yes / Congruent with economic stability and environmental sustainability, the ninth Sustainable Development Goal (SDG - Industry, Innovation and Infrastructure) plays a crucial role in undergirding the industrial revolution. Conversely, it is inevitably complex for underdeveloped and emerging economies to meet the ninth SDG's 2030 agenda due to a lack of sufficient financial resources and the slow adoption of technology. With China expanding its Belt and Road Initiatives (BRIs) globally, mainly few findings espouse the significant link between BRI and the ninth SDG, and its probable impact remains understudied. Hence, a considerable gap yet exists in contemporary understanding of the impact of BRI on sustainability. Therefore, we conducted an exploratory study on six different countries (Algeria, Ghana, Indonesia, Malaysia, Nigeria and Palestine) to investigate the role of the BRI in achieving the ninth SDG. Face-to-face interviews and focus group discussions were applied. This qualitative data collection technique involved 26 participants representing industry experts and academic researchers. All interviews were recorded, transcribed, translated and thematically analysed. The result showed a significant progressive impact of BRI on the ninth SDG, and that the development of sustainable infrastructure is a key antecedent of the BRI policy enforcement in the six countries explored. The result also showed positive and negative spillover effects of BRI projects in the six countries. Government and Policymakers should design and enforce pro-growth and sustainable strategies to facilitate continuous implementation of policies that would align the execution of the BRI projects to bolster achievement of the ninth SDG.

Page generated in 0.3764 seconds