This diploma thesis is focused on behavior of cement concrete at high temperatures. The theoretical part describes processes, which take place in concrete at thermal loading and effect of this thermal load to mechanical and physical properties of concrete. Also there was described recommendation for testing physical and mechanical of concrete at high temperatures according to RILEM TC. In experimental part mixes were made with greywacke aggregate, amphibolite aggregate and with the addition of polypropylene fibers or cellulose fibers. In these mixes was determined the effect of high temperatures on the density of concrete, compressive strength of concrete and thermal strain of concrete. Further there was tested addition of 2 kg/m3 polypropylene fibers to concrete with basalt aggregate and siliceous aggregate and influence of these fibers to density of concrete, compressive strength of concrete and dynamic modulus of elasticity.

<p>Den här uppsatsen är skriven inom ramen för ämnet <em>Krigsvetenskap</em> under författarens studier på <em>Yrkesofficersprogrammet</em> 2006-2009 till arméteknisk officer. I <em>Ammunitions- och minröjning i modern konflikt</em> ges läsaren genom deskriptiv metod en exposé över ammunitions- och minröjningens grunder, historia och nutid. Uppsatsens generella syften är att avhandla problematik som svenska ammunitions- och minröjare i sitt yrkesutövande idag kan ställas inför. Och hur delar av den tekniska organisationen och teknisk utrustning för detektion, lokalisering och klassificering av minor, Explosive remnants of war (ERW), Improvised explosive device (IED) och försåt kan bidra till att lösa denna problematik. Författaren genomför utifrån sina intervjuer och litteraturstudier prediktioner av den kommande utvecklingen på området. Prediktionerna innefattar bland annat tydligare teknisk stödorganisation och multisensorplattformar för detektion, lokalisering och klassificering av minor, ERW och IED. I texten redovisas viss forskning från Totalförsvarets forskningsinstitut (FOI) och visst arbete vid Försvarets materielverk (FMV), Totalförsvarets ammunitions- och minröjningscentrum (SWEDEC).</p> / <p>This essay is written in the course of <em>War science</em> during the author’s studies to become an Officer in the technical corps, in the Swedish armed forces. Due to the descriptive method in <em>Explosive Ordnance Disposal and demining in modern conflict </em>the reader gets an exposé of the basics, history, and present time features for the Swedish EOD- and Demining personnel. The main purpose with this essay is to discuss the problems that Swedish Explosive ordnance clearance (EOC) personnel might encounter in their current daily service. The opportunities for parts of the supporting technical corps and the technical equipment for detecting, locating and classifying mines, Explosive remnants of war (ERW), Improvised explosive device (IED) and booby-traps to be at hand in the process of solving these problems are also discussed. From interviews and literature studies the author conducts predictions of the development in the subject area. The predictions contains amongst others a more understandable supporting technical corps and multi-sensing-platforms for detecting, locating and classifying mines, ERW, IED and booby-traps. Some of the research that the Swedish defence research agency (FOI), the Swedish Defence Material Administration (FMV) and the Swedish EOD- and Demining Centre (SWEDEC) have produced is presented in the essay.</p>

In the boreal forests of the Northern Hemisphere, time series of tree-ring width (TRW) and maximum density in the latewood (MXD) are highly correlated to local instrumental summer-temperature data and are thus widely used as proxies in high-resolution climate reconstructions. Hence, much of our present knowledge about climatic variability in the last millennium is based on tree-rings. However, many tree-ring records have a lack of data in the most recent decades, which severely hampers our ability to place the recent temperature increase in a longer-timescale perspective of natural variability. The main objective of this thesis is to update and extend the Torneträsk TRW and MXD records in northern Sweden. Local instrumental climate-data is used to calibrate the new tree-ring records. The results show that TRW is mainly forced by temperature in the early growing season (June/July) while MXD has a wider response window (June – August) and has a higher correlation to temperature. Two reconstructions of summer temperature are made for (i) the last 7,400 years based on TRW, and (ii) the last 1,500 years based on a combination of TRW and MXD. The reconstructions show natural variability on timescales from years to several centuries. The 20th century does not stand out as a notably warm period in the long timescale perspective. A medieval period from AD 900 – 1100 is markedly warmer than the 20th century. The environmental impact from a large explosive volcanic eruption in 1628/1627 BC is analysed in the tree rings of 14C-dated bog pines in south-central Sweden and in absolutely-dated subfossil pines from Torneträsk. The results show evidence of an impact in the southern site at approximately this time but no detectable impact in the North. Subfossil trees of Fitzroya cupressoides in southern Chile were 14C-dated to approx. 50,000 years BP and amalgamated into a 1,229-year TRW chronology. This tree-ring record is the oldest in the world. The variability in this Last-glacial chronology is similar to the variability in present-day living trees of the same species. These results suggest that the growth–forcing mechanisms 50,000 years ago were similar to those at present.

Syftet med undersökningen är att genom en jämförande modellstudie ta fram ett eller flera sätt att nedkämpa en motståndare utrustad med tungt reaktivt pansar. Reaktivt pansar har tidigare endast använts för att hindra RSV-strålar att penetrera pansar. Men teknikutvecklingen har nu medfört att dagens reaktiva pansar utöver skydd mot RSV-strålar också klarar av att reducera pilprojektilens förmåga till penetration. Amerikanarna som tidigt upptäckte att Ryssland hade tillgång till tekniken började direkt utveckla ny ammunition för att möta detta. Men vad har vi gjort i Sverige, sen detta uppdagades? Kan vår Stridsvagn 122 fortfarande lösa sin huvuduppgift: att slå ut andra stridsvagnar? I studien gör författaren antagandet att spårljuspansarprojektil 95 inte får genomslag på en stridsvagn utrustad med tungt reaktivt pansar, typ Kontakt-5. Undersökningen har sin tyngdpunkt i den jämförande modellstudie som skall jämföra tre olika scenarion. Modellstudien föregås av en beskrivande teoridel där bland annat skydd, svensk stridsvagnsammunition och reaktivt pansar beskrivs. Därefter behandlar modellstudien en duellsituation mellan Strv 122 och en motståndare utrustad med Kontakt-5. De olika modellerna jämförs i syfte att ta fram den modellen som är mest fördelaktig då man vill nedkämpa en fiende utrustad med Kontakt-5. Slutsatsen som dras utifrån studien är att normalförfarandet att initialt ha pilprojektil i kanonen bör ändras till att istället ha spränggranat. Spränggranaten kommer att skada Kontakt-5 och skapa en oskyddad yta där pilprojektilen kan få genomslag. / The purpose of this essay is to develop one or more ways to neutralize an enemy equipped with heavy reactive armour. Reactive armour has previously only protected against shaped charges. Technological advances have now led to today's reactive armour in addition to protection against shaped charges also capable of protecting against an Armour-Piercing Fin-Stabilized Discarding Sabot (APFSDS). The Americans discovered that this technology was available to the Russians and developed new types of APFSDS to deal with it. But what have we done in Sweden since this technology was discovered? In this essay, the author makes the assumption that the Swedish APFSDS can’t penetrate a tank equipped with reactive armour. A comparative model will compare three different ways to deal with this problem. Before doing the comparative model study, there will be a chapter which describes for example reactive armour, APFSDS, Kontakt-5 (a type of reactive armour), tank protection in general. The model consists of one Leopard 2A5 S (Leo 2) and one enemy tank equipped with reactive armour. By comparing different ways for the Leo 2 to defeat the enemy, the author will reach a conclusion for the problem. The conclusion drawn from this essay is that the normal procedure when the Leo 2 initially has an APFSDS loaded in the canon should be changed to it having a grenade loaded instead. Bursting a grenade towards the enemy will destroy or damage Kontakt-5 and the second projectile, which should be an APFSDS, will now penetrate the damaged Kontakt-5 and the hostile tank will be defeated.

Den här uppsatsen är skriven inom ramen för ämnet Krigsvetenskap under författarens studier på Yrkesofficersprogrammet 2006-2009 till arméteknisk officer. I Ammunitions- och minröjning i modern konflikt ges läsaren genom deskriptiv metod en exposé över ammunitions- och minröjningens grunder, historia och nutid. Uppsatsens generella syften är att avhandla problematik som svenska ammunitions- och minröjare i sitt yrkesutövande idag kan ställas inför. Och hur delar av den tekniska organisationen och teknisk utrustning för detektion, lokalisering och klassificering av minor, Explosive remnants of war (ERW), Improvised explosive device (IED) och försåt kan bidra till att lösa denna problematik. Författaren genomför utifrån sina intervjuer och litteraturstudier prediktioner av den kommande utvecklingen på området. Prediktionerna innefattar bland annat tydligare teknisk stödorganisation och multisensorplattformar för detektion, lokalisering och klassificering av minor, ERW och IED. I texten redovisas viss forskning från Totalförsvarets forskningsinstitut (FOI) och visst arbete vid Försvarets materielverk (FMV), Totalförsvarets ammunitions- och minröjningscentrum (SWEDEC). / This essay is written in the course of War science during the author’s studies to become an Officer in the technical corps, in the Swedish armed forces. Due to the descriptive method in Explosive Ordnance Disposal and demining in modern conflict the reader gets an exposé of the basics, history, and present time features for the Swedish EOD- and Demining personnel. The main purpose with this essay is to discuss the problems that Swedish Explosive ordnance clearance (EOC) personnel might encounter in their current daily service. The opportunities for parts of the supporting technical corps and the technical equipment for detecting, locating and classifying mines, Explosive remnants of war (ERW), Improvised explosive device (IED) and booby-traps to be at hand in the process of solving these problems are also discussed. From interviews and literature studies the author conducts predictions of the development in the subject area. The predictions contains amongst others a more understandable supporting technical corps and multi-sensing-platforms for detecting, locating and classifying mines, ERW, IED and booby-traps. Some of the research that the Swedish defence research agency (FOI), the Swedish Defence Material Administration (FMV) and the Swedish EOD- and Demining Centre (SWEDEC) have produced is presented in the essay.

One of the most important properties of an explosive is its velocity of detonation (VOD). It is essential that the explosive should detonate at its optimum rate and release sufficient detonation pressure to get good fragmentation under the existing field conditions. The main objectives of this research study are to investigate the effects of explosive type, blast hole diameter, and degree of confinement on the VOD of bulk ANFO and bulk emulsion in Kumtor Open Pit Gold Mine. In this study, the continuous resistance wire method is employed to measure in-situ VOD of both bulk ANFO and bulk emulsion. The VOD values are measured for different hole diameters and under different confinements for both explosives. The ideality of bulk ANFO and bulk emulsion is calculated by comparing the in-situ measured VOD&rsquo / s and their ideal detonation values. It is found that the VOD of both explosives increases as the blast hole diameter and the degree of confinement increases. In addition to this, VOD of bulk ANFO decreases when it gets wet in the blast hole. Another finding is that, proportion of bulk emulsion ingredients has influence on its VOD. This research study provides a good understanding to use suitable explosive in existing rock conditions in Kumtor Open Pit Gold Mine.

La vaporisation explosive, ou flashing, par dépressurisation rapide du C6F14 au travers d'une vanne à boisseau sphérique est analysée expérimentalement sur une grande plage de surchauffe. Les visualisations rapides montrent un jet s'ouvrant très largement en aval, preuve de l'existence d'un fort gradient de pression. Des mesures locales par sonde optique et par vélocimétrie phase Doppler ont permis de caractériser tailles, vitesses, concentration et flux numérique des gouttes en fonction de la surchauffe. La faible influence du degré de surchauffe sur la remontée en pression et sur les tailles et flux de gouttes suggère que le champ de pression s'adapte, et que par conséquent le liquide est soumis à une surchauffe locale bien plus faible que la surchauffe globale imposée. Différents scenarii sont discutés pour expliquer les observations, dont le fait que les tailles de gouttes sont peu sensibles à la surchauffe. Celui basé sur l'existence d'un front d'ébullition est le plus probable.

Nitrocellulose is the main component in many types of ammunition, propellants and explosives. The principles of production for nitrocellulose have not changed much since the 19th century when it started being industrially produced for this purpose. The character of the nitrocellulose has a large effect on the end products abilities. The aim of this study was to develop a method that would be able to characterise and distinguish between nitrocellulose from different manufacturers to be able to relate the character of the nitrocellulose to the properties of ammunition, propellants and explosives. Samples were dissolved in acetone and analysed by GC/MS and data were then analysed by multivariable statistics. FTIR was also used to characterise the nitrocellulose. Results from both methods showed very small differences when chromatograms and spectra were analysed. This study shows that GC/MS and FTIR are not suitable for this type of characterisation. The differences between the data were not sufficient to be able to separate the samples from each other. / Nitrocellulosa är den viktigaste komponenten i många typer av ammunition, drivmedel och sprängämnen. Principerna för produktionen av nitrocellulosa har inte förändrats mycket sedan det börjades produceras industriellt för detta ändamål på 1800 talet. Karaktären av nitrocellulosa har en stor inverkan på slutproduktens egenskaper. Syftet med denna studie var att utveckla en metod som skulle kunna karaktärisera och skilja mellan nitrocellulosa från olika tillverkare för att kunna relatera karaktären av nitrocellulosa till egenskaperna hos ammunition, drivmedel och sprängämnen. Proverna löstes i aceton och analyserades med GC/MS och data analyserades med multivariabel statistik. FTIR användes också för att karakterisera nitrocellulosan. Resultaten för båda proverna visade mycket små skillnader när kromatogram och spektra analyserades. Denna studie visar att GC/MS och FTIR inte är lämpliga för denna typ av karaktärisering. Skillnaderna i data var inte tillräckliga för att kunna skilja proverna från varandra.

Made available in DSpace on 2014-12-17T14:48:14Z (GMT). No. of bitstreams: 1 JanainaSS_DISSERT.pdf: 4645317 bytes, checksum: 1f500f6eaf05e8ac34d38ba500240ab2 (MD5) Previous issue date: 2013-04-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The reinforced concrete structures are largely used in buildings worldwide. Upon the occurrence of fire in buildings, there is a consensus among researchers that the concrete has a high resistance to fire, due mainly to its low thermal conductivity. However, this does not mean that this material is not affected by exposure to high temperatures. Reduction of the compressive strength, modulus of elasticity, discoloration and cracking, are some of the effects caused by thermal exposure. In the case of concretes with higher resistance occurs even desplacamentos explosives, exposing the reinforcement to fire and contributing to reducing the support capacity of the structural element. Considering the above, this study aims to examine how the compressive strength and porosity of concrete are affected when subjected to high temperatures. Were evaluated concrete of different resistances, and even was the verified if addition fibers of polyethylene terephthalate (PET) in concrete can be used as an alternative to preventing spalling. The results indicated that explosive spalling affect not only high strength concrete whose values of this study ranged from 70 to 88 MPa, as well as conventional concrete of medium strength (52 MPa) and the temperature range to which the concrete begins to suffer significant changes in their resistance is between 400 ? C and 600 ? C, showing to 600 ? C a porosity up to 188% greater than the room temperature / As estruturas de concreto armado s?o largamente utilizadas nas edifica??es em todo o mundo. Quando da ocorr?ncia de inc?ndio em edifica??es, ? consenso entre os estudiosos, que o concreto apresenta uma elevada resist?ncia ao fogo, devido principalmente a sua baixa condutividade t?rmica. No entanto, isto n?o significa que esse material n?o seja afetado pela exposi??o a elevadas temperaturas. Redu??o de resist?ncia ? compress?o e no m?dulo de elasticidade, altera??o na colora??o e aparecimento de fissuras, s?o alguns dos efeitos causados pela exposi??o t?rmica. No caso de concretos com resist?ncia mais elevada, ocorre ainda desplacamentos explosivos, expondo as armaduras ao fogo, e contribuindo assim para a redu??o da capacidade suporte do elemento estrutural. Diante do exposto, o presente trabalho tem por objetivo analisar como a resist?ncia ? compress?o e a porosidade do concreto s?o afetadas quando submetido a elevadas temperaturas. Foram avaliados concretos de diferentes resist?ncias, e ainda foi verificado se a incorpora??o de fibras de politereftalato de etileno (PET), em matriz de concreto, pode ser usada como alternativa a preven??o do lascamento. Os resultados indicaram que lascamentos explosivos acometem n?o somente os concretos de alta resist?ncia, cujos valores desta pesquisa variaram de 70 a 88 MPa, como tamb?m o concreto convencional de m?dia resist?ncia (52 MPa), e que a faixa de temperatura para o qual o concreto come?a a sofrer altera??es expressivas em sua resist?ncia fica entre 400 ?C e 600 ?C, apresentando aos 600 ?C uma porosidade at? 188% maior que a apresentada a temperatura ambiente

This master’s thesis studies the problems of high temperatures on cement concretes, their following diagnostics from pre-treatment to rehabilitation, the emphasis was on the use of high-speed water jet. In the experimental part of the design of a concrete composition with basalt aggregate. Were reviewed the physico-mechanical properties after thermal loading. The influence of pressure water jet on the thermal load on concrete, pull-off test, the volume of the removed concrete with a strength evaluation and comparison.