221 |
Wasserstrahldichtung: ein Beitrag zur Abdichtung beweglicher Konstruktionen im WasserbauAigner, Detlef 22 November 1983 (has links)
No description available.
|
222 |
Zwei Anwendungsbeispiele für TextilbetonBrameshuber, Wolfgang, Mott, Rebecca 03 June 2009 (has links)
In dieser Veröffentlichung werden 2 Anwendungsbeispiele für Textilbeton vorgestellt, ein nachträgliches Abdichtungssystem sowie eine bauteilintegrierte Schalung. Teil 1: Da in vielen Regionen Deutschlands steigende Grundwasserspiegel zu verzeichnen sind und bestehende Gebäude, die nicht für den Belastungsfall „drückendes Wasser“ ausgelegt sind, mit einem tragfähigen nachträglichen Abdichtungssystem ertüchtigt werden müssen, wurde ein entsprechendes Abdichtungssystem aus Textilbeton entwickelt. Durch die Verwendung des Textilbetons ist es möglich, ein Abdichtungssystem mit einer geringen Bauteilstärke von 30 mm im Spritzverfahren herzustellen. Teil 2: Die bauteilintegrierte Schalung (BIS) aus Textilbeton nimmt während der Betonage den Frischbetondruck auf. Im Endzustand bildet sie die Bauteiloberfläche und kann Anforderungen hinsichtlich Tragfähigkeit, Sichtbeton- und Oberflächenqualität sowie Oberflächenausbildung (Farbe, Struktur) erfüllen. BISElemente können werksmäßig wirtschaftlich und qualitativ hochwertig hergestellt werden.
|
223 |
Management půd velkých investičních akcí na příkladu průmyslové zóny Kolín - Ovčáry / Soil management of large investment projects on the example of the industrial zone Kolín - OvčáryBejblová, Klára January 2010 (has links)
The thesis deal with the soil sealing and the rehanding with the uncovering of soil cultural layers. This problem is describe on the example of the industrial zone Kolín - Ovčáry. In the thesis there is the evaluation of the soil characteristics and their changes in areas where due to the trensfer of the cultural layer was created completely new structure of soil cover compact of soil units with artificial stratigraphy of profile. For this area the new classification subsumtion is suggested. The overall impacat of the soilsealig and implementation of the uncovering of soil cultural layers, despite of local incerase of soil fertility parameters, we evaluate as the degradation of soil cover.
|
224 |
Evaluation of soil erosion in the Harerge region of Ethiopia using soil loss models, rainfall simulation and field trialsBobe, Bedadi Woreka 02 August 2004 (has links)
Accelerated soil erosion is one of the major threats to agricultural production in Ethiopia and the Harerge region is not exceptional. It is estimated that about 1.5 billion tones of soil is being eroded every year in Ethiopia. In the extreme cases, especially for the highlands, the rate of soil loss is estimated to reach up to 300 t ha-1yr-1 with an average of about 70 t ha -1yr-1 which is beyond any tolerable level. The government have made different attempts to avert the situation since 1975 through initiation of a massive program of soil conservation and rehabilitation of severely degraded lands. Despite considerable efforts, the achievements were far bellow expectations. This study was aimed at assessing the effect of some soil properties, rainfall intensity and slope gradients on surface sealing, soil erodibility, runoff and soil loss from selected sites in the Harerge region, eastern Ethiopia, using simulated rainfall. Soil loss was also estimated for the sites using Soil Loss Estimation Model for Southern Africa (SLEMSA) and the Universal soil Loss Equation (USLE). Moreover, the effectiveness of various rates and patterns of wheat residue mulching in controlling soil loss was also evaluated for one of the study sites, (i.e. Regosol of Alemaya University), under both rainfall simulation and field natural rainfall conditions. For most of the erosion parameters, the interaction among soil texture, slope gradient and rainfall intensity was significant. In general however, high rainfall intensity induced high runoff, sediment yield and splash. The effect of slope gradients on most of the erosion parameters was not significant as the slope length was too small to bring about a concentrated flow. The effect of soils dominated by any one of the three soil separates on the erosion parameters was largely dependent on rainfall intensity and slope gradient. The soils form the 15 different sites in Harerge showed different degrees of vulnerability to surface sealing, runoff and sediment yield. These differences were associated with various soil properties. Correlation of soil properties to the erosion parameters revealed that aggregate stability was the main factor that determined the susceptibility of soils to sealing, runoff and soil loss. This was in turn affected by organic carbon content, percent clay and exchangeable sodium percentage (ESP). Soils with relatively high ESP such as those at Babile (13.85) and Gelemso (7.18) were among the lowest in their aggregate stability (percent water stable aggregates of 0.25 –2.0mm diameter); and have highest runoff and sediment yield as compared to other soils in the study. Similarly, most of those soils with relatively low ESP, high organic carbon content (OC%) and high water stable aggregates such as Hamaressa, AU (Alemaya University) vertisol and AU regosol were among the least susceptible to sealing and interrill erosion. Nevertheless, some exceptions include soils like those of Hirna where high runoff was recorded whilst having relatively high OC%, low ESP and high water stable aggregates. Both the SLEMSA and USLE models were able to identify the erosion hazards for the study sites. Despite the differences in the procedures of the two models, significant correlation (r = 0.87) was observed between the values estimated by the two methods. Both models estimated higher soil loss for Gelemso, Babile, Karamara and Hamaressa. Soil loss was lower for Diredawa, AU-vertisol and AU-Alluvial all of which occur on a relatively low slope gradients. The high soil loss for Babile and Gelemso conforms with the relative soil erodibility values obtained under rainfall simulation suggesting that soil erodibility, among others, is the main factor contributing to high soil loss for these soils. The difference in the estimated soil losses for the different sites was a function of the interaction of the various factors involved. Though the laboratory soil erodibility values were low to medium for Hamaressa and Karamara, the estimated soil loss was higher owing to the field topographic situations such as high slope gradient. SLEMSA and USLE showed different degrees of sensitivities to their input variables for the conditions of the study sites. SLEMSA was highly sensitive to changes in rainfall kinetic energy (E) and soil erodibility (F) and less sensitive to the cover and slope length factors. The sensitivity of SLEMSA to changes in the cover factor was higher for areas having initially smaller percentage rainfall interception values. On the other hand, USLE was highly sensitive to slope gradient and less so to slope length as compared to the other input factors. The study on the various rates and application patterns of wheat residue on runoff and soil loss both in the laboratory rainfall simulation and under field natural rainfall conditions revealed that surface application of crop residue is more effective in reducing soil loss and runoff than incorporating the same amount of the residue into the soil. Likewise, for a particular residue application method, runoff and soil loss decreased with increasing application rate of the mulch. However, the difference was not significant between 4 Mg ha-1 and 8 Mg ha-1 wheat straw rates suggesting that the former can effectively control soil loss and can be used in areas where there is limitation of crop residues provided that other conditions are similar to that of the study site (AU Regosols). The effectiveness of lower rates of straw (i.e. less than 4 Mg ha-1 ) should also be studied. It should however be noted that the effectiveness of mulching in controlling soils loss and runoff could be different under various slope gradients, rainfall characteristics and cover types that were not covered in this study. Integrated soil and water conservation research is required to develop a comprehensive database for modelling various soil erosion parameters. Further research is therefore required on the effect of soil properties (with special emphasis to aggregate stability, clay mineralogy, exchangeable cations, soil texture and organic matter), types and rates of crop residues, cropping and tillage systems, mechanical and biological soil conservation measures on soil erosion and its conservation for a better estimation of the actual soil loss in the study sites. Copyright 2004, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. Please cite as follows: Bobe, BW 2004, Evaluation of soil erosion in the Harerge region of Ethiopia using soil loss models, rainfall simulation and field trials, PhD thesis, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-08022004-141533 / > / Thesis (PhD (Soil Science))--University of Pretoria, 2004. / Plant Production and Soil Science / unrestricted
|
225 |
Application of Dynamic Grouting to Improve the Grout Spread Using Varying Aperture Long Slot (VALS) : AN EXPERIMENTAL STUDYHosseini, Robabeh, Steven, Yalta January 2018 (has links)
In the past centuries, grouting has been one of the most common techniques in geotechnical engineering to strengthen and seal underground structures. Concerning increasing demands for tightness and cost efficiency, cement-based grout has been one the most frequent used materials. One of the first grouting operations is the work done by Charles Bérigny in France back in 1802 in order to repair a sluice by stabilizing the ground with liquid grout. Several studies have been then conducted in grouting, which have contributed into successful improvement of the grouting operations. The investigations have also extended the understanding of the factors such as choice of materials, choice of equipment, and the applied pressure type and magnitude, etc. that influencing the grout spread in rock fracture systems. Among the factors, the applied pressure is one of the most significant ones influencing the spread of grout during grouting operations. Grouting at static pressure conditions is the most common method used in field, where in practice the injected grout can only penetrate into the rock fractures wider than 100 µm. Recent investigations conducted on application of static and dynamic pressure conditions, using Short Slot and Varying Aperture Long Slot (VALS) in the lab have yielded an overall improvement of the grout spread under dynamic pressure conditions rather than the conventional static pressure conditions. However, the efforts conducted are just a beginning, especially in very fine micro factures smaller than 70 µm The main objective of this investigation was therefore to improve the spread of grout by dynamic grouting into fractures smaller than 70 µm effectively, which could not be done with grouting at static pressure conditions. Furthermore, the aim was to investigate filtration and erosion phenomena/ tendency of grout flow during static and dynamic pressure application using Varying Aperture Long Slot (VALS) in the lab. The durations of peak and rest periods used in the experiments were 2s/2s and 1s/5.5s, which were equivalent to 0.25 Hz and 0.15 Hz, respectively. The results of dynamic grouting showed up to 10 times improvement in the volume of passed grout through fracture apertures smaller than 70 µm. / Injektering är en av de vanligaste metoderna som använts för att förstärka och täta geotekniska konstruktioner. När det gäller ökande krav på täthet och kostnadseffektivitet har cementbaserade bruk varit ett populärt förbrukningsmaterial. Injektering användes förmodligen först av Charles Bérigny i en slussreparation i Frankrike under 1802 där marken stabiliserades med hjälp av flytande injekteringsmaterial. Flera studier har sedan dess utförts inom injekteringsteknik, vilket har bidragit till en framgångsrik förbättring av injekteringsoperationer. Dessa undersökningar har också utvidgat förståelsen av faktorer såsom materialegenskaper, val av utrustning, provprestanda, trycktyp och storhet som i sin tur påverkar brukets spridningsförmåga i bergets spricksystem. Forskningen inom bergtätning fokuserar bland annat på att utveckla tillämpningen av statisk och dynamisk tryck vid injektering. Tillämpning av statiskt tryck är den vanligaste metoden för injektering ute i arbetsfält, där den injicerade bruket i praktiken endast kan tränga in i bergssprickor som är större än 100 μm. De senaste undersökningarna med hjälp av Short Slot och Varying Aperture Long Slot (VALS) har visat en övergripande förbättring av inträngningen under dynamisk injektering jämfört med de konventionella statiska. Detta är bara en början och metoden behöver utvecklas mer, särskild för att åstadkomma bruksspridningen i mycket finare mikrosprickor, exempelvis sprickor mindre än 70 µm. Syftet med detta arbete var att utveckla injekteringsmetoden där bruket kan tränga i berg med sprickor mindre än 70 µm. Resultaten på de dynamiska tryckförhållanden visade att injekteringsbruket trängde bättre i de smala sprickor jämfört med de statiska tryckförhållanden. Upp till 10 gånger mer mängd av injekteringsbruk passerade sprickor med storlek mindre än 70 µm i VALS. Vidare har inloppsflödet och filtrerings- och erosionsfenomenen studerats med hjälp av laboratorieinstrumentet VALS. Varaktigheten av peak- och restperioder som användes i experimenten var 2s/2s och 1s 5.5s, vilka var ekvivalenta med 0.25 Hz respektive 0.15 Hz.
|
226 |
Charakterisierung und Bewertung von Dichtprinzipien für den Einsatzbereich in der Innenhochdruck-Umformung (IHU) von dünnwandigen, rohrförmigen Bauteilen: SFU 2023Fischer, Pierre, Reuter, Thomas, Güra, Thomas, Grundmann, Andreas 06 March 2024 (has links)
Das Innenhochdruck-Umformen (IHU), ein Verfahren der Metallformung zur Herstellung von anspruchsvollen Bauteilen mit komplexer Geometrie aus meist hohlzylindrischen Halbzeugen, wird in einigen Branchen seit mehreren Jahrzehnten mit großem Erfolg angewendet. Insbesondere die vielfältigen Applikationen aus dem Automotivbereich wie z.B. Elemente der Abgasanlage, Strukturbauteile oder auch Antriebselemente können hergestellt werden. Da die Trends der Rohr- und Blechumformung in Richtung Leichtbau, komplexer Bauteile mit geringen Ausbringungsmengen und hoher Genauigkeit gehen, ist perspektivisch mit der Erschließung weiterer Anwendungs-gebiete zu rechnen. Um das Verfahren effizienter zu gestalten, können zusätzliche Prozesse in das IHU-Verfahren integriert werden. Beispiele dafür sind das Lochen sowie das Kragenziehen und weitere Fügeprozesse. Typische Bauteile sind Leicht-baunockenwellen, bei denen die Nocken innerhalb des Umformprozesses auf die Rohre form- und kraftschlüssig gefügt werden. Ungeachtet einer beliebigen dreidimensionalen Formgebung und der hohen Flexibilität unterliegt das IHU-Verfahren gewissen Restriktionen. So werden im industriellen Umfeld generell nur Halbzeuge mit Wanddicken ab 1,5 mm bis maximal 3,5 mm umgeformt. Bei dünnwandigen, rohr-förmigen Bauteilen sind Wanddicken unter 1 mm üblich. Diese erfordern spezielle technologische Maßnahmen im Bereich des Werkzeugbaus insbesondere Anforderungen an Dichtsystem sowie Werkzeuggravur und unterliegen Prozessparametern mit entsprechend kleineren Prozessfenstern.
|
227 |
Characterization and evaluation of sealing principles for use in hydroforming (IHU) of thin-walled, tubular components: SFU 2023Fischer, Pierre, Reuter, Thomas, Güra, Thomas, Grundmann, Andreas 06 March 2024 (has links)
Hydroforming, a metal forming process for the production of sophisticated components with complex geometries from mostly tubular semi-finished products, has been successfully applied in some industries for several decades. Particularly, various applications from the automotive sector such as elements of the exhaust system, structural components or drive elements can be manufactured. As trends in tube and sheet metal forming move towards lightweight construction, complex components with low production volumes, and high precision, the prospective expansion into further application areas is anticipated. To enhance the efficiency of the process, additional processes can be integrated into the hydroforming process. Examples of this are punching, collar pulling and other joining processes. Typical components include lightweight camshafts in which the cams are form- and force-fitted onto the tubes within forming process. Despite arbitrary three-dimensional forming and the high degree of flexibility, the hydroforming process is subjected to certain restrictions. Generally, in an industrial environment, only semi-finished products with wall thicknesses from 1.5 mm to a maximum of 3.5 mm are formed. Wall thicknesses of less than 1 mm are common for thin-walled, tubular components. These require special technological measures in the area of toolmaking, particularly regarding sealing system and tool engraving, and are subjected to process parameters with correspondingly smaller process windows
|
228 |
Double-Sealing Recycled Paper Parcels in Sustainable Marketing & Consumer Decision-Making Factors. : The case Study of PostNord Logistics and Customers.Kebede, Abel, Shafique, Zunair January 2023 (has links)
Abstract: - This Master’s Thesis explains the relevancy of sustainable marketing, sustainability, e-commerce, circular economy of recycled paper packaging in the correlation of consumer perception, consumer decision making factors towards recycling and sustainability benefits. Although the paper discusses sustainable marketing in a circular economy aspect potential in regards to recycled paper parcels, the research will mainly focus on the postal carrier company named PostNord based in Nordic countries; the paper will emphasise how the double-sealing recycled paper could increase the number of customers and sustainability ofthe company and consumer perception towards these type of packaging as a parcel. The concept of Sustainability Marketing and Consumer Behaviour has been around for awhile. Since its emergence in the 1980s, the idea has evolved. Much research has been done regarding sustainability marketing, also known as green marketing. As the world is becoming environmentally polluted, many industries propagate it, and consumers need more sustainable products and services. Due to this reason and other respective consumer needs, companiesfrom the manufacturing and service industry have made a strategy to implement short andlong-term to become sustainable companies by becoming carbon-free. Accordingly, postal carrier companies worldwide have developed various sustainable marketing strategies and technological tools to reduce carbon emissions. They simultaneously promote sustainability marketing based on consumer behaviour and perception. The research paper mainly focuses on sustainable marketing, sustainable marketing in the circular economy, and consumer perception and factors affecting consumers’ purchase intention regarding the broad applicability and benefits of double-sealing recycled paperparcels for packaging in the postal service industry. For this particular Master’s thesis paper, the research has taken PostNord as a case study and developed an alternative sustainablemarketing and consumer perspective concerning: Circular economy through the use of recycled paper parcels, organisational resource utilisation, increased current & new customer,consumer perception towards recycled paper parcels, Consumer purchase intention towardsRecycled paper parcels &amp; E-commerce with packaging. The research paper is developed and has referred to various scholarly articles such as Escursell (2021), Kotler (2012) and several other scholars, including yearly sustainability reports of PostNord. The annual sustainability reports of PostNord have mainly focused on increasing its sustainability through technological tools, transportation systems, service and customer relations. This research paper is developed through a cross sectional research method study provided that PostNord is the case study related to using double-sealing recycled paper parcels as an alternative product to its current and potential consumers while increasing their sustainability.
|
229 |
Experimental study on CO2-sensitive polyacrylamide as potential in-situ sealing agent for CO2 leakage pathways in geological storage sitesQuan Lopez, Iris Laihmen 09 August 2022 (has links)
As the world pushes for ‘greener’ technologies and carbon neutrality, efforts have focused on creating novel ways to mitigate humankind’s carbon footprint. Carbon capture and storage (CCS) has become a prevalent technique that has proven to be an effective long-term method to safely relocate excess carbon dioxide (CO2) into subsurface formations. However, CCS is a newer technique which requires constant monitoring due to potential leakage pathways present in CO2 storage sites; therefore, a preventive approach to seal leakage pathways is recommended. This dissertation explores the potential of CO2-sensitive polyacrylamide (CO2-SPAM) as a novel sealing agent for enhanced oil recovery (EOR) and CCS applications. This manuscript explores the strength and weaknesses of various CO2-triggered chemicals and selects the appropriate fit for subsurface in-situ sealing. Relevant literature shows that CO2-SPAM can significantly reduce permeability in porous media. Additionally, organically cross-linked polyacrylamide-based gels, of which CO2-SPAM is one, are thermally stable, resistant to low pH levels, highly injectable, and widely used in various industrial processes. These characteristics make CO2-SPAM a suitable candidate for in-situ sealing. Further studies were performed to comprehend the chemical mechanism, rheological behavior, and injection effects of CO2-SPAM into subsurface formations. Firstly, past literature knowledge and organic chemistry principals were used to develop the complete chemical breakdown of CO2-SPAM gel’s synthesis. Secondly, the effect of salt and polyacrylamide (PAM) concentrations on gelation time, gel strength and viscosity were tested through qualitative (Sydansk gel strength coding system) and quantitative methods (rheometer measurement). The results showed that high salinities increase gelation time and decrease gel strength and viscosity, while high PAM concentrations do the opposite. Lastly, the effects on geomechanical stresses caused by CO2-SPAM injection into the subsurface are also addressed by using the image well method for pore pressure estimation, and frictional faulting theory. The final results determined that the injection of aqueous CO2-SPAM would induce seismicity in normal faulting zones dipping at a large array of angles in the plane of failure. These findings are significant as they determine the potential of induced seismicity in the area of CCS, which in this case was the Raton basin.
|
230 |
Enclosing and Mounting an Electronic Component on Articulated Haulers : A proposition on how to protect, and where to place, an intelligent node on the environmentally harsh exterior of construction equipment with respect to multiple parametersSintorn, Johan January 2016 (has links)
As is the case with many other manufacturers of vehicles, Volvo Construction Equipment has a constantly increasing amount of electric and electronic equipment in their articulated haulers. These are of great use in modern machines, bringing functions, and safety that were not possible before, but they also bring more cables to handle. In the case of the articulated haulers a quite thick cable harness of about 15 meters in length reaches from the driver’s cabin in the front to the components in the far back end of the vehicle. This is not only a lot of long cables to handle both during assembly and service, but the nature of signals traveling in cables is that the voltage gets weaker with distance. This phenomenon has to be accounted for by measuring devices dependent on the voltage. It has been suggested that a device referred to as an intelligent node, or ICCS-module, which communicates digitally via CAN could be installed in the back of the articulated haulers. This module would be independent of the mentioned drop in voltage. The ICCS-module will be receiving a small bundle of cables being routed from the driver’s cabin. From it cables would go out to a majority of the components in its vicinity. The components connected to the node would not need to have any other cables. This thesis is focused on the mechanical aspects of installing this ICCS-module. Having electric and electronic equipment on construction vehicles is a challenge when it comes to protecting the device from the harsh environment that is the hauler’s exterior. It will have to withstand being immersed in water for long periods of time, greatly varying temperatures, vibrations and shocks as well as being hit by projectiles. The placement as well as the design of the enclosure should be chosen with respect to both the devices length of life and how well it fulfils its intended role and achieves the expected results. To produce an enclosure and find a placement aiming to satisfy these conditions, a traditional product development process were executed. The articulated haulers as well as relevant literature were researched. Concepts were generated and evaluated by both the author and by employees at Volvo Construction Equipment until a final concept for the enclosure and placement were found. The enclosure were then designed in detail specifying the material, manufacturing techniques, controlled for thermodynamic circumstances, modelled in Catia V5 and controlled for vibrations. It was concluded that the enclosure should be able protect the ICCS-module after some more development and that the placement and cable routing results in a much shorter total cable length.
|
Page generated in 0.0492 seconds