Vid röjning av RSV-ammunition saknas idag adekvat beslutstöd för att dimensionera skadebegränsande åtgärder mot jetstrålens verkan. I uppsatsen vidareutvecklas en beräkningsmodell som författaren tidigare föreslagit. Syftet är att skapa ett verktyg som kan införas i ammunitionsröjningsverksamheten. Fullskaliga skjutförsök har genomförts för att klarlägga inverkan av förhållanden som är typiska vid ammunitionsröjning; en skyddskonstruktion byggd av sandsäckar och med ett långt detonationsavstånd till röjningsobjektet. Försöksresultatet visar att den grundläggande hydrodynamiska penetrationsteorin inte är användbar för dessa förhållanden. Vidare ger sandsäckskonstruktionen signifikant bättre skydd mot jetstrålen än en homogen grusbädd. Genom störningsanalys har känsligheten hos de enskilda parametrarna i beräkningsmodellen för verksamhetstypiska fel utretts. Härefter har Monte Carlo-simulering använts för att analysera den sammanlagda inverkan som dessa fel kan ge. Resultatet har legat till grund för att bestämma modellens säkerhetsmarginal. Militär nytta innebär att modellen skall kunna tillämpas fältmässigt, med korta tidsförhållanden och utan tillgång till avancerade beräkningshjälpmedel. Detta har lett fram till att ett enkelt diagram inkluderats i det kompletta dimensioneringsverktyget. Verktyget föreslås införas i regelverk och utbildningssystem för att avhjälpa den brist som råder idag. / During the clearance of shaped charge ammunition, explosive ordnance disposal (EOD) personnel lack adequate means for the design of protective measures against the jet. In this thesis a calculation model, previously suggested by the author, is developed further. The aim is to create a tool that can be applied to EOD operations. Full-scale experiments have been conducted to clarify the effects of conditions that are typical for EOD operations: protective measures built from sandbags with a long standoff distance to the ordnance. The results indicate that the hydrodynamic penetration theory is not suitable for these conditions. Furthermore, a sandbag construction provides significantly better protection against the jet than a homogeneous gravel construction. By disturbance analysis, the sensitivity of the individual parameters in the model is studied for typical errors. Subsequently, Monte Carlo simulation has been used to analyse the effect these errors can cause. The simulation results have then been the used to determine the model´s margin of safety. Military utility implies that it should be possible to use the model under field conditions, with limited time frames and without access to advanced calculating means. This has resulted in a simple diagram included in the comprehensive design tool. It is proposed that the tool is implemented in regulations and curricula in order to remedy today’s lack of decision support.

Arbuscular mycorrhizal (AM) fungi are root and soil inhabiting symbionts with higher plants. The fungi are especially nutrient-function efficient in nutrient deficient soils. There have been innumerable studies of AM fungal facilitation of plant nutrient uptake in controlled environments. Comparatively little similar investigation has been undertaken in natural soils, including investigation of taxon specific nutrient-function efficiency in the phylum. Plant diversity and frequency, soil chemistry statuses, and AM spore diversity and abundance were sampled in an interrupted-belt transect in an aggrading dune sytem on west-coast India, followed by foredunes and transect nutrient amendment experiments in selected plant species. The transect extends 175 m inland from mean high-water mark (MH-WM). Examination showed nutrients were consistently deficient. A plant zonation pattern and increasing frequency over the transect were indicated, as well as decreasing pH and increasing organic matter (OM)-amendment AM species diversity gradients. Plant zonation does not correlate with soil chemistry. There was a distinct soil transition at the 175 m point and evidence of further system partition between foredune and behind-foredune regions. Plant and AM demographies bore no resemblance suggesting neither is driven by the other. Four AM genera were recovered, Acaulospora, Gigaspora and Scutellospora in high abundance, Glomus in comparatively low abundance. The two co-dominant species, A. spinosa and Gi. margarita, displayed divergent strategies in OM amendment. Certain AM taxa may be functionally associated with particular soil nutrients. There was no evidence of taxon-specific nutrient-function efficiency.

Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The hypothesis postulated in this research, namely that the effectiveness of natural and constructed buffer dune systems can be assessed by a set of indicators that defines the integrity of the dune system and triggers informed management decisions, was evaluated and proved to be essentially true. Two key objectives, namely (1) the identification of key indicators that define the buffer dune integrity; and (2) the development of a scientifically defendable and practical checklist-based method of gathering qualitative information on the identified key indicators so as to guide decision-making at municipal level formed the core of the study. The six dune integrity indicators that collectively define the risk profile of a particular site along the Southern Cape coastline are (1) the degree of protection from prevailing wave energy, (2) the characteristics of the dominant winds and sand supply during the dry season, (3) the relative height of the foredune, (4) the degree of pressure on the buffer dune due to humans, (5) the vulnerability of the type of coastline to erosion, and (6) the coastline stability considering the prevailing coastal processes. The first two indicators relate to the natural (permanent) characteristics of the site and can be defined by experts and presented in the form of a risk and vulnerability atlas layer for direct use by non-experts. The third and fourth indicators relate directly to the implementation of proactive assessment and appropriate management actions to ensure a high level of buffer dune integrity. The last two indicators allow for management intervention to reduce the vulnerability but may entail costly engineering solutions and require expert input. A conceptual risk profile assessment procedure and a decision support guideline incorporating these indicators were developed and evaluated for relevance and practicality through a series of workshops with municipal officials along the south coast of South Africa. It was seen that although some initial basic training may be required, carrying out rapid assessments of the environmental status of key components of an identified human–nature system, such as a buffer dune, is practical and achievable by non-experts. / AFRIKAANSE OPSOMMING: Die hipotese wat in hierdie navorsing gepostuleer is, naamlik dat die doeltreffendheid van natuurlike en geboude bufferduinstelsels geassesseer kan word deur ’n stel aanwysers wat die integriteit van die duinstelsel bepaal en ingeligte bestuursbesluite tot gevolg het, is getoets en bewys hoofsaaklik waar te wees. Twee sleuteldoelwitte, naamlik (1) die identifisering van sleutelaanwysers wat die bufferduinintegriteit bepaal; en (2) die ontwikkeling van ’n praktiese kontrolelys-gebaseerde metode wat wetenskaplik verdedigbaar is om kwalitatiewe inligting oor die geïdentifiseerde sleutelaanwysers in te samel ten einde besluitneming op munisipale vlak te bevorder, vorm die kern van die studie. Die ses duin-integriteitsaanwysers wat gesamentlik die risikoprofiel van ’n bepaalde terrein langs die kuslyn bepaal, is (1) die graad van beskerming teen die heersende golfenergie, (2) die kenmerke van die dominante winde en sandbron gedurende die droë seisoen, (3) die relatiewe hoogte van die voorduin, (4) die graad van druk op die bufferduin as gevolg van mense, (5) die eroderingskwesbaarheid van die soort kuslyn, en (6) die kuslynstabiliteit met inagname van die kusprosesse. Die eerste twee aanwysers het betrekking op die natuurlike (permanente) eienskappe van die terrein en kan deur kundiges bepaal word en in die vorm van ’n kaart in ’n risiko-enkwesbaarheidsatlas aangebied word vir direkte gebruik deur niedeskundiges. Aanwysers 3 en 4 hou direk verband met die implementering van tydige en deurlopende proaktiewe assessering en gepaste bestuursaksies om ’n hoë vlak van bufferduinintegriteit te verseker. Aanwysers 5 en 6 bevorder bestuursaksies om kwesbaarheid te verminder, maar kan moontlik duur ingenieursoplossings inhou en kundige insette benodig. ’n Konseptuele risikoprofielassesseringsprosedure en ’n besluitondersteuningsriglyn wat die aanwysers insluit, is ontwikkel en geëvalueer vir toepaslikheid en uitvoerbaarheid deur ’n reeks werkswinkels met munisipale amptenare aan die suidkus van Suid-Afrika. Hoewel aanvanklike basiese opleiding nodig kan wees, bly dit dat vinnige assessering van die omgewingstatus van sleutelkomponente van ’n geïdentifiseerde mens–natuurstelsel, soos ‘n bufferduin, prakties en haalbaar deur niedeskundiges is.

Betong är idag och har länge varit det allra vanligaste byggnadsmaterial i Sverige. Det är ett robust och mångsidigt byggnadsmaterial med flera fördelar. Detta arbete är en experimentell studie av betongavfall från Hedareds sand & betong för betongprogrammet RE: Concrete och Högskolan i Borås. Betongavfallet krossas till ny ballast och därefter siktas och gjuts till ny betong enligt olika betongrecept. Försöken sker i betonglabbet i Högskolan i Borås för att krossa och tillverka betong. Grundreceptet har tillhandhållits av Hedareds sand & betong. Syftet med arbetet har varit att undersöka möjligheterna för att kunna använda återvunnen betong i nya bärande konstruktioner. Målet var att bevisa att det var tekniskt möjligt att åstadkomma en 100 % ersättning av ballast med återvunnen betong och få fram ny betong som passar den bärande stommen i en byggnad. Olika egenskaper undersöktes så som tryckhållfasthet för den nya betongen och partikelfördelning samt vattenabsorption för ballasten med målet att uppnå likvärdigt resultat som för referensbetongen. Resultatet visar att det är möjligt att kunna återvinna betong till 100 %. Arbetbarheten är bra i flertal försök men bör förbättras för att uppnå likvärdig arbetbarhet som referensbetongens. Referensbetongens tryckhållfasthet är 59 MPa och bästa tryckhållfasthet som erhållits för återvunnen betong är 57,2 MPa. Detta tyder på ett positivt resultat och den återvunna betongen i denna studie kan ersätta naturgrusballast i en bärande konstruktion till 100 %. / Concrete is and has been for a long time the most common building material in Sweden. It is a robust and multipurpose building material with several advantages. This report is about an experimental study of concrete waste from Hedareds sand & betong. The concrete waste is crushed to a new aggregate and then sifted and casted into new concrete. The study was conducted in the Concrete Laboratory at University of Borås for crushing and casting of concrete. Recipes are supplied by Hedareds sand & betong as a starting point, which is later modified gradually to achieve better results. The purpose of this study is to investigate the possibilities for using recycled concrete in new constructions. It is also examined if the recycled concrete is technically sustainable and if the workability is good enough for using in load bearing structures. Different properties are studied such as compressive strength, particle distribution, water absorption and workability to achieve equivalent results as the reference concrete. The result obtained in this study shows that it is possible to recycle concrete by replacing aggregates to 100 % in new concrete. Workability is good in several tests, but it should be improved to achieve the same workability as the reference concrete. The reference concrete's compressive strength is 59 MPa and the best compressive strength obtained for recycled concrete is 57.2 MPa. This indicates positive results and the recycled concrete in this study can replace ordinary concrete in a load bearing construction.

In this thesis and in my graduation project, I am taking a closer look at the word temporary. It is an investigation in the transition between the two states: temporary and permanent. I am using the contrasting state permanent as an anti-pole to get perspective and to have a fair comparison. I want to give the state of temporarily a shape or a face and to define time through the material and design, like a time capsule. As an interior architect I am questioning the usage of the temporary in the architectural and giving it attention by using architecture, furniture, states and materials as my framework.

O preparo de misturas de areia-asfalto a frio com emulsão asfáltica possui algumas características que dificultam a avaliação de seu desempenho através de ensaios de laboratório. Estas características são atribuídas à emulsão asfáltica que necessita de cuidados adicionais em relação a outros tipos de ligantes betuminosos. Um desses cuidados é o procedimento de cura antes da compactação para favorecer a perda de umidade das misturas. Neste trabalho é avaliada a influência da perda de umidade de três tipos de misturas de areia-asfalto a frio - misturas sem filler, com filler de pedregulho britado e com filler de cimento Portland, sobre os resultados de alguns ensaios de laboratório. Os ensaios usados para esta avaliação foram: dosagens sem cura e com cura antes da compactação das misturas; controle da perda de umidade; ensaios Marshall com variação da perda de umidade e fluência por compressão uniaxial estática. A perda de umidade antes da compactação das misturas mostrou-se um importante fator de influência nos resultados do ensaio Marshall. Porém, o ensaio de fluência por compressão uniaxial estática revelou que mesmo as misturas com melhor desempenho no ensaio Marshall são muito suscetíveis à deformação permanente e com ruptura frágil mesmo sob a ação de tensões axiais relativamente baixas. / The preparation of cold sand-asphalt mixtures with asphalt emulsion has some characteristics that can affect the laboratory evaluation of its performance. These characteristics are attributed to asphaltic emulsion that needs additional cares in relation to others types of bituminous binders. One of these cares is the curing procedure before compaction, to favor moisture loss. In this work the influence of moisture loss on the results of some laboratory tests is evaluated for three cold sand-asphalt mixtures - mixtures without filler, with crushed gravel filler and with portland cement filler. The tests used for this evaluation are: optimum asphalt content with and without curing before the mixtures compaction, moisture loss control, Marshall tests with moisture loss variation and static creep test. Moisture loss before compaction showed to have a clear influence on the results of Marshall tests. However the static creep test revealed that even those mixtures with the best Marshall test performances are very susceptible to permanent deformation and fragile rupture under low axial stress.

O preparo de misturas de areia-asfalto a frio com emulsão asfáltica possui algumas características que dificultam a avaliação de seu desempenho através de ensaios de laboratório. Estas características são atribuídas à emulsão asfáltica que necessita de cuidados adicionais em relação a outros tipos de ligantes betuminosos. Um desses cuidados é o procedimento de cura antes da compactação para favorecer a perda de umidade das misturas. Neste trabalho é avaliada a influência da perda de umidade de três tipos de misturas de areia-asfalto a frio - misturas sem filler, com filler de pedregulho britado e com filler de cimento Portland, sobre os resultados de alguns ensaios de laboratório. Os ensaios usados para esta avaliação foram: dosagens sem cura e com cura antes da compactação das misturas; controle da perda de umidade; ensaios Marshall com variação da perda de umidade e fluência por compressão uniaxial estática. A perda de umidade antes da compactação das misturas mostrou-se um importante fator de influência nos resultados do ensaio Marshall. Porém, o ensaio de fluência por compressão uniaxial estática revelou que mesmo as misturas com melhor desempenho no ensaio Marshall são muito suscetíveis à deformação permanente e com ruptura frágil mesmo sob a ação de tensões axiais relativamente baixas. / The preparation of cold sand-asphalt mixtures with asphalt emulsion has some characteristics that can affect the laboratory evaluation of its performance. These characteristics are attributed to asphaltic emulsion that needs additional cares in relation to others types of bituminous binders. One of these cares is the curing procedure before compaction, to favor moisture loss. In this work the influence of moisture loss on the results of some laboratory tests is evaluated for three cold sand-asphalt mixtures - mixtures without filler, with crushed gravel filler and with portland cement filler. The tests used for this evaluation are: optimum asphalt content with and without curing before the mixtures compaction, moisture loss control, Marshall tests with moisture loss variation and static creep test. Moisture loss before compaction showed to have a clear influence on the results of Marshall tests. However the static creep test revealed that even those mixtures with the best Marshall test performances are very susceptible to permanent deformation and fragile rupture under low axial stress.

Afin d’optimiser le procédé de production de culasses automobiles en aluminium et d’améliorer sa fiabilité, une meilleure connaissance du comportement des noyaux de fonderie est nécessaire. Les noyaux sont des matériaux composés de grains de sable liés par une résine en faible proportion, et servent à mouler les conduits et cavités intérieurs des pièces métalliques. Au cours de leur cycle de vie, les noyaux sont amenés à subir de fortes températures et des sollicitations mécaniques complexes. L’objectif de cette étude est de caractériser le comportement thermomécanique des noyaux sous diverses sollicitations selon le taux de liant, la température et surtout l’état de dégradation de ce liant. En particulier, les travaux de cette thèse s’attardent sur les mécanismes d’endommagement et de fissuration des noyaux, dont la compréhension est la clé pour optimiser l’étape de débourrage qui consiste en la fracturation et l’élimination des noyaux. Les résultats de cette thèse serviront par ailleurs à nourrir un modèle numérique simulant le débourrage des pièces. Différents modes de chargements mécaniques ont été étudiés : flexion, compression, cisaillement, push-out, fatigue, fluage ou encore compression œdométrique. Ils correspondent à différents types de sollicitations, avec ou sans confinement du noyau, et permettent de caractériser soit le cœur ou la surface du matériau. L’endommagement peut être suivi grâce à la réalisation de cycles de décharge-recharge. Dans tous les cas, le comportement mécanique du noyau est fortement dépendant des propriétés et de l’état du liant. Ainsi, la dégradation thermique induite par la coulée de l’aluminium liquide modifie et dégrade nettement les propriétés du noyau. Des parallèles peuvent ainsi être dressés entre les propriétés du liant, le comportement mécanique du matériau sable/résine et l’endommagement microstructural observé après rupture. / Better knowledge about the mechanical behavior of foundry sand cores is required in order to optimize the aluminum cylinder head production process. Sand cores allow the casting of complex shape metallic parts and are made of sand grains, bound with a resin in low proportion. Sand cores are subjected to high temperatures and complex mechanical load during the production process. This study aims at characterizing the thermomechanical behavior of sand cores under various loads depending on the binder proportion, the temperature and mostly the binder thermal degradation. Particularly, we focus on the cores damage and fracture mechanisms. The understanding of such phenomena could lead to an optimization of the decoring step, consisting in the fracture and removing of the core from the metallic part. Indeed, the results of this Ph.D. thesis will be used to implement a numerical model of the decoring process. Different kinds of mechanical loads have been studied: bending, compression, shear, push-out, fatigue, creep or also oedometric tests. They correspond to different kinds of load, with or without confining pressure and allow a characterization of the bulk or the surface of the material. The core damage is followed by mechanical tests with unload-reload cycles sequences. For all the cases, the core mechanical behavior is highly dependent on the binder properties and thermal degradation. For example, the thermal degradation induced by the aluminum casting modifies and degrades significantly the core properties. Analogies could be drawn between the binder properties, bonded-sand cores mechanical behavior and the evolution of the fracture surfaces.

The aim of this study was to develop and examine the use of backscatter data collected with multibeam sonar (MBS) systems for benthic habitat mapping. Backscatter data were collected from six sites around the Australian coastal zone using the Reson SeaBat 8125 MBS system operating at 455 kHz. Benthic habitats surveyed in this study included: seagrass meadows, rhodolith beds, coral reef, rock, gravel, sand, muddy sand, and mixtures of those habitats. Methods for processing MBS backscatter data were developed for the Coastal Water Habitat Mapping (CWHM) project by a team from the Centre for Marine Science and Technology (CMST). The CMST algorithm calculates the seafloor backscatter strength derived from the peak and integral (or average) intensity of backscattered signals for each beam. The seafloor backscatter strength estimated from the mean value of the integral backscatter intensity was shown in this study to provide an accurate measurement of the actual backscatter strength of the seafloor and its angular dependence. However, the seafloor backscatter strength derived from the peak intensity was found to be overestimated when the sonar insonification area is significantly smaller than the footprint of receive beams, which occurs primarily at oblique angles. The angular dependence of the mean backscatter strength showed distinct differences between hard rough substrates (such as rock and coral reef), seagrass, coarse sediments and fine sediments. The highest backscatter strength was observed not only for the hard and rough substrate, but also for marine vegetation, such as rhodolith and seagrass. The main difference in acoustic backscatter from the different habitats was the mean level, or angle-average backscatter strength. However, additional information can also be obtained from the slope of the angular dependence of backscatter strength. / It was shown that the distribution of the backscatter. The shape parameter was shown to relate to the ratio of the insonification area (which can be interpreted as an elementary scattering cell) to the footprint size rather than to the angular dependence of backscatter strength. When this ratio is less than 5, the gamma shape parameter is very similar for different habitats and is nearly linearly proportional to the ratio. Above a ratio of 5, the gamma shape parameter is not significantly dependent on the ratio and there is a noticeable difference in this parameter between different seafloor types. A new approach to producing images of backscatter properties, introduced and referred to as the angle cube method, was developed. The angle cube method uses spatial interpolation to construct a three-dimensional array of backscatter data that is a function of X-Y coordinates and the incidence angle. This allows the spatial visualisation of backscatter properties to be free from artefacts of the angular dependence and provides satisfactory estimates of the backscatter characteristics. / Using the angle-average backscatter strength and slope of the angular dependence, derived by the angle cube method, in addition to seafloor terrain parameters, habitat probability and classification maps were produced to show distributions of sand, marine vegetation (e.g. seagrass and rhodolith) and hard substrate (e.g. coral and bedrock) for five different survey areas. Ultimately, this study demonstrated that the combination of high-resolution bathymetry and backscatter strength data, as collected by MBS, is an efficient and cost-effective tool for benthic habitat mapping in costal zones.

No description available.