Dissertations / Theses on the topic 'Emulsion explosives'

This study investigated the formulation and characterisation of emulsion explosives. This included the manufacture of more than 120kg of emulsion explosive of which around 105kg was used on the explosive ordnance range in over 350 individual firings. For each emulsion composition, an average of eight firings was undertaken with which to substantiate the explosive performance data. The formulation was varied to determine the effects of water content upon the physical characteristics of the emulsion. These physical effects included thermal conductivity, particle size, viscosity and the explosive performance of the emulsion. In respect of explosive performance, microballoons were added to sensitise the emulsion and the proportions of microballoons added were altered to look at their effect on velocity of detonation, sensitivity and the brisance of the emulsions. Emulsion explosives are commonly referred, in literature, as Type 11 non-ideal explosives. This is due to their non-linear behaviour with respect to the variation of velocity of detonation with density. Traditionally, when an emulsion explosive was commercially manufactured, the water content has been kept at a minimum (12-17%). This was accepted as the way to achieve the best explosive performance, based upon the belief that an emulsion with the highest concentration of active ingredients, ammonium nitrate and oil, would give the best explosive performance. This study examined a wider range of emulsion explosive water contents than has been previously studied, from 12% to 35% water. It was found, during this study, that higher water content emulsions, specifically 25% water, had a marked increase in explosive performance. The highest velocity of detonation recorded was in a 39mm diameter tube, at 25% water content with 3% microballoons, was 5558ms-1. This was some 15% higher than any other VOD recorded in this study. The high velocity of detonation, at 25% water content, was one of a number of physical characteristics in which this water content varied from the other emulsion water contents. This study endeavored to show that emulsion explosives could exhibit two differing types of explosive reaction, thermal explosion and grain burning. This was based on the velocity of detonation and plate dent data, both of which indicated that there was a change in reaction with water content. Emulsion explosives, with a high water and high microballoon content, exhibited a thermal explosion type reaction. They exhibited Type I ideal explosive behaviour, with increasing velocity of detonation with density. Lower water content emulsion explosives, displayed the more commonly expected Type 11 non-ideal behaviour and reacted in a grain burning type detonation.

An energy optimised Tree Branch Methodology was developed to overcome the multiple minima problem in molecular mechanics calculations of acyclic molecules. Target molecules were assembled one heavy atom at a time from small precursors, and the energy minimized after each addition. The number of structures to be minimised was significantly reduced by following the lowest energy path in the Tree Branch Method. Comparison of the calculated configurations to minimum energy structures obtained from complete conformational search is made.
The compression of fatty acid monolayers in Langmuir-Blodgett trough experiments at the air/water interface was modelled using a two dimensional array. The minimum energy configuration of the acids was obtained using the Tree Branch Methodology, and the water coordination number determined by comparison of calculated and experimentally measured dipole moments. The variation in measured dipole moments as the hydrated head group was compressed were explained.
Minimum energy configurations of known surfactant molecules used in the preparation of water-in-oil emulsion explosives were obtained through the Tree Branch Methodology, and the optimised geometries used to calculate structural parameters assuming standard van der Waals radii around each atom. Comparison of the structural parameters to the stability of the emulsions in which the surfactants were used, allowed preliminary structural criteria to be established. Based on the structural criteria, a number of new families of surfactant head group were designed, and preliminary rules for matching head to tail group combinations proposed.

The aim of this study was to understand and control the gasification rates in ammonium nitrate emulsion explosive using ammonium nitrate-sodium nitrite reaction. This reaction produces N2 gas which is the sensitizer in emulsion explosives. The NH4NO3-NaNO2 gassing reaction produces N2 gas and so the reaction could be followed by the pressure increase in a closed reaction vessel. The reaction is pH sensitive, so the role of pH was investigated in the pH range 2 to 5. Gasification reactions for unbuffered NH4NO3-NaNO2 reaction were found to be rapid below pH = 3 and maximum pressure was attained within 2 hours of starting the reaction. At pH = 4.5 and 5 the reaction failed to attain maximum pressure. Initial rate of reaction showed sensitivity to pH, the rate of reaction decreasing with increasing pH. The reaction was found to be second order with respect to nitrite species. The effects of three different buffers (potassium hydrogen phthalate, sodium formate and sodium citrate) were also investigated. At pH = 3 pressure traces for the buffered reactions had attained maximum pressure while at pH = 3.5 only sodium citrate buffer had reached a pressure stable state. The presence of the buffers resulted in a lower overall pressure change and absolute pH change and higher rate constants and initial rate of reaction than in their absence. iv A Lewis acid (Zinc Nitrate) was added to the buffered and unbuffered NH4NO3-NaNO2 reactions to investigate a patent claim that addition of a Lewis acid would increase the rate of reaction. The presence of zinc nitrate in the buffered reactions resulted in rapid pressure increase; higher initial rate of reactions than the unbuffered with zinc nitrate. Ammonium nitrate solution was emulsified resulting in an ammonium nitrate emulsion explosive and kinetics of gasification was investigated. The gasification reactions were found to be rapid at pH 3.2, slowing significantly with increased pH as indicated by initial rates of reaction and as predicted by the gasification reaction rate law. Maximum pressure increase was attained within three hours at pH 3.2, whereas reactions conducted at pH 4.0 and 4.5 failed to reach maximum pressure even after 24 hours as evidenced by plots of pressure versus time. The effect of buffers in the ammonium nitrate emulsions was also investigated.

Dissertation submitted in fulfilment of the requirements for the Masters Degree in Technology: Chemical Engineering in the Department of Chemical Engineering of Cape Peninsula University ofTechnology, 2005
The emulsion used for this study is a new thermodynamically unstable multi-component waterin- oil (w/o) explosive type with an internal phase ratio of approximately 94%, i.e. far beyond the close packing limit of spherical droplets of 74%. Economic considerations and the ongoing need for continuous drilling, loading and blasting in the mining industry, has made long-distance pipeline transportation of these emulsion explosive systems a viable economic option. Presently, rheological characterization of emulsion explosives is well documented (Bampfield & Cooper, 1988, Utracki, 1980). However, very little or none has been done for this system, pertaining to the use of rheometry for prediction of pumping characteristics of these systems in long-distance pipeline transport. This Master's dissertation is devoted to develop rheological methods of testing, characterization and correlation in order to develop a basis for predicting the pumping characteristics of highly concentrated w/o emulsion explosives from rheometry. The literature and theory pertinent to the pipeline flow of high internal phase ratio emulsion explosives are presented, as well as the fundamentals of both concentric cylinder rheometry and pipe viscometry. The most relevant is the work of Bampfield and Cooper (1988), Utracki (1980) and Pal (1990). Two experimental test facilities were used for data collection. Pipeline experiments were done using an experimental test facility at African Explosives Limited (AEL), and rheometry was conducted at the Rheology Laboratory of the Cape Peninsula University of Technology Flow Process Research Centre. The AEL experimental test facility consisted of a four-stage Orbit progressive cavity pump, two fluid reservoirs, (a mixing tank and a discharge reservoir), five 45m HOPE (high density polyethylene) pipes of internal diameters of 35.9 mm, 48.1 mm, 55.9 mm, 65.9 mm and 77.6 mm pipes. The test work was done over a wide range of laminar flow rates ranging from 3 kg.min-I to 53 kg.min-I . Rheometry was done using a PaarPhysica MCR300 rheometer, and only standard rotational tests (i.e. flow curve) at 30 °c in controlled rate mode were done. Rheological characterisation was done using three rheological models, i.e. the Herschel-Bulkley, the Power Law and the Simplified Cross models. The coefficients obtained from these models were then used to predict pumping characteristics. The performances of these models were then evaluated by comparing the pipeline flow prediction to the actual pipeline data obtained from pipeline test experiments. It was found that the flow behaviour depicted by this explosive emulsion system was strongly non-Newtonian, and was characterized by two distinct regions of deformation behaviour, a lower Newtonian region of deformation behaviour in the shear rate region lower than 0.001 S-I and a strong shear thinning region in the shear rate range greater than 0.001 S-l. For all the models used for this study, it was evident that rheometry predicts the pumping characteristics of this high internal phase ratio emulsion reasonably well, irrespective of the choice of the model used for the predictions. It was also seen that the major difference between these models was in the lower shear rate domain. However, the Simplified Cross model was preferred over the other two models, since its parameter (the zero shear viscosity denoted by 110) can in general be correlated to the structure of the emulsion systems (i.e. mean droplet size, bulk modulus, etc.). Thus, structural changes induced by shearing (either inside the pump or when flowing inside a pipe) can be detected from changes in the value of the 110. The above statement implies that Tlo can be used as a quality control measure. Different pumping speeds were found to cause different degrees of shear-induced structural changes which were manifested by two opposing processes. These two opposing processes were the simultaneous coalescence and flocculation of droplets encountered at low rates of shear, and the simultaneous refinement and deflocculation of droplets encountered at high rates of shear. These two droplet phenomena were associated with a decrease or an increase in viscous effects, leading to both lower and higher viscous stresses and pumping pressures during pump start-up respectively.

Excavation damage is usually regulated in Swedish infrastructure tunnel contracts as it can influence the quality and lifecycle cost for tunneling projects. The topic is important for underground constructions with a long operation period such as tunnels for public transport, permanent access tunnels in mines or underground repositories for nuclear waste. In competent crystalline rock, excavation damage is often simplified to macro fractures induced by blasting as this has the most significant impact on the remaining rock. Blasting in Scandinavian tunneling projects is mostly conducted with pumpable emulsion explosives and a good result is often dependent on control of the charging process, i.e. that the explosives are charged according to the blast design. This thesis is based on data from five field investigations carried out in Sweden and Finland. In addition, data from a case study on quality control and documentation in a tunnel excavation project in Äspö Hard Rock Laboratory (HRL) is also included. Data on blast fracture length and frequency have been compiled from all sites, where emulsion explosives were used. The sites include experimental tunnels, a road tunnel, an underground depot for subway trains and a wastewater tunnel. Data from the field investigations have been analyzed using statistical methods including statistical hypothesis test and multivariate data analysis by means of Principal Component Analysis (PCA). The evaluation method gives indications as to how blast design and geology influence the development of blast fractures. Charge concentration was found to be the most influential design variable and simultaneous initiation of contour holes (delay time <1 ms) gave shorter blast fractures with a longest blast fracture of approx. 25 cm compared to approx. 40 cm from pyrotechnical initiation. However, the delay time had limited influence on the number of blast fractures in the remaining rock. Results from the PCA suggest that blast fractures length could be dependent also on geology. Three main groups of fracture patterns were identified, one group with relatively few and short fractures, a group with several longer blast fractures and a group with few or a single long blast fracture. The result shows differences in fracture length between the column and bottom charge part of the contour holes, with blast fracture lengths up to approx. 40 cm for the column charge and up to approx. 60 cm for the bottom charge. The case study showed that good precision in charging with string emulsion can be achieved and documented using modern logger technology in drilling and charging equipment. However, the methods applied for evaluation of charging precision as well as documentation require manual processing and interpretation of data. Further development of the logger systems and processing software is needed in order to follow up logged amounts of emulsion explosive during production.

The aim of this study was to investigate the dynamic properties of potassium chloride, AN solutions and a commercial emulsion explosive and to understand their response in terms of shock theory and material properties. A plate impact facility was used to shock the KCl, subjecting it to a uni-axial strain state for the duration of the measurements. Stress and strain histories were recorded using piezo-resistive gauges. KCl is an ionic crystal which, when subject to shocks above 2.2 GPa, has a martensitic phase transformation. The stress histories were explained in terms of the shock and release waves. A novel technique was used to record the reverse phase transformation and to calculate the hysteresis. The assumption that a uni-axial strain state exists behind a phase transformation was verified, for the first time, experimentally. Two techniques were demonstrated that reduce and quantify the piezo-electric response of KCl. Conclusions from this investigation were analysed by two different types of computational simulation. Using a similar methodology to the KCl work a technique has been developed to determine experimentally the Hugoniot of liquids up to pressures of 10 GPa. The Hugoniots of a variety of AN solutions of different strengths and temperatures were recorded. The results were shown to agree with the predictions of two simple equations of state. The technique developed for AN solutions was applied to a commercial emulsion explosive (based on an AN solution) and the Hugoniot determined. The explosive was sensitised by adding quantities of glass micro-balloons and the pressures which induced the first stages of reaction for a given sensitisation were deduced.

Emulsion explosives have become the preferred choice as blasting agents for numerous industries including mining, agriculture, and construction. One of the most important components in such an emulsion is an emulsifier, which controls the emulsification properties of the explosive. The present study involves the production of one such emulsifier, which is produced by reacting two immiscible liquids, PIBSA (polyisobutylene succinic anhydride) and MEA (monoethanolamine). The study examines the effect of design variable such as the impeller speed, impeller type and the dispersed phase volume fraction on interfacial area. Experiments were carried out in a 0.15 m diameter fully baffled stirred tank using a 6-bladed Rushton turbine impeller and a marine propeller. Drop size was determined using a microscope with a video camera and image processing system. The transient concentration of PIBSA was determined using FTIR analysis and used to estimate the volume fraction of the dispersed phase (ƒÖ). The effective interfacial area was calculated using the Sauter mean drop diameter, d32 and ƒÖ. Impeller speeds ranging from 150 to 600 rpm and dispersed phase volume fractions, ƒÖ ranging from 0.01 to 0.028 were examined in the experimental study. It was found that that the evolution of Sauter mean drop diameter, d32 has four different trends depending on ƒÖ and impeller speed. At high impeller speeds and high ƒÖ, d32 values decrease initially and reach constant values after a long period of time. This trend is consistent with the findings in previous investigations. Under certain operating conditions, d32 values increase initially with stirring time to reach a maximum value and then decrease to reach a steady state value. The presence of these trends has been attributed to the effect of changing physical properties of the system as a result of chemical reaction. Results indicate that, in general, Sauter mean drop diameter d32 decreases with an increase in agitation intensity. However a decrease in the dispersed phase volume fraction is found to increase d32. These trends are found to be the same for both impeller types studied. Comparing the drop size results produced by the two impellers, it appears that low-power number propeller produces s ignificantly smaller drops than the Rushton turbine. It was found that the concentrations of reactants decrease with time for all impeller speeds thereby leading to a decrease in interfacial area with the progress of the reaction. Interfacial area values obtained at higher impeller speeds are found to be lower in spite of lower d32 values at these speeds. Also, these values decrease with time and become zero in a shorter duration indicating the rapid depletion of MEA. The interfacial area values obtained with the propeller at a given impeller speed are lower as compared to those for Rushton turbine. They also decrease and become zero in a shorter duration as compared to those for Rushton turbine suggesting propeller¡¦s performance is better in enhancing the reaction rate.

Highly concentrated ammonium nitrate emulsions are extensively used as an explosive in the mining industry. The emulsion is made from a supercooled aqueous salt solution with various stabilisers and an organic hydrocarbon phase under vigorous stirring to room temperature. The resulting emulsion is thermodynamically unstable and tends to crystallise over time. This is not suitable for the transportation or pumping of the emulsion in its application. This study showed that the crystallisation process of highly concentrated ammonium nitrate emulsions can be influenced by varying the emulsion droplet size as well as the types and ratios of surfactants used during the preparation stage. The results showed that there were significant differences in the rheological properties of the freshly-prepared emulsion, based on both the emulsion droplet size, and the type of surfactant and ratio of surfactants used. A decrease of the emulsion droplet size resulted in the increase of the elastic character, which can be explained by more compact network organisation of droplets. In terms of the different surfactants, it was shown that the Pibsa-Imide stabilised emulsions resulted in an emulsion with the highest storage modulus over the entire strain amplitude regions as well as the highest shear stresses over the whole shear rate region. The study showed that the relatively slow emulsion crystallisation process can be studied by using powder X-ray diffraction (PXRD). The amount of amorphous and crystalline phases present in the sample can be effectively quantified by using the Partial Or No Known Crystal Structural (PONKCS) method which can model accurately the contributions of the amorphous halo. An external standard calibration method, which used a different amorphous material with the crystalline material to obtain a suitable calibration constant, was employed. The results showed that the method would quantify the amount of the fully crystallised emulsion to be between 80 and 90 percent, which was in agreement with the solid content added during sample preparation and confirmed by Thermal Gravimetric Analysis (TGA). The simultaneous TGA / DSC results were able to show the number of solid/solid peak transitions as well as the total moisture content to be around 20 percent by mass in various emulsion samples studied. The study was able to model the crystallisation by using the Avrami and Tobin kinetic relationships which are commonly used for the crystallisation processes of polymers. The Avrami relationship proved to be useful in describing the type of crystallisation that occurred. This was based on literature where the exponent parameter (n) which was between 1 and 4 would relate to different types of crystallisation models. The results of this study showed that the crystallisation process would change for the samples that had shown a longer crystallisation process. The results indicated that the samples prepared with the lower Pibsa-Urea ratio showed a more sporadic crystallisation process, whereas the samples with the higher ratio of Pibsa-Urea showed a more controlled crystallisation process. The study also considered the rheological properties of the fresh emulsion, which showed that droplet size also had an influence on the stress strain relationship of the emulsion droplets.

La presente investigación está enfocada en la industria de explosivos, la cual trabaja directamente con distintos sectores en el país, tales como el sector de construcción, el sector de defensa y la industria minera, siendo esta última la que durante los últimos 60 años ve a los explosivos como recurso necesario y primordial, para ejercer su determinado fin. Por esto, el foco de la presente tesis es analizar cuáles son los principales factores que influyeron a las exportaciones de explosivos fabricados a partir del nitrato de amonio (emulsiones), las cuales poseen la partida arancelaria (3602002000), durante los años 2006 al 2017 hacia nuestro país vecino del sur Chile. Para esto la investigación tomo como base diversos estudios tales como Dynamite Market Global Forecast, Global Ammonium Nitrate Explosive Market Size and Industry Trends los cuales detallan sobre un conjunto de factores que impulsan el crecimiento del mercado de explosivos en el mundo. Asimismo, este estudio se basa en un enfoque cualitativo para la determinación de los principales factores y un enfoque cuantitativo para el análisis de la información recabada. En una primera etapa cualitativa, se logró contrastar e identificar una serie de factores claves que influenciaron directamente a las exportaciones de emulsiones peruanas, las cuales se obtuvieron a partir de entrevistas a profundidad realizadas a especialistas dedicados a este rubro. Posterior a la identificación de los factores se compararon los datos obtenidos en una segunda parte de la investigación, la cual se basa en un análisis cuantitativo sobre la información obtenida. .
The present investigation is focused on the explosives industry, which works directly with different sectors in the country, such as the construction sector, the defense sector and the mining industry, the latter being the one that during the last 60 years sees explosives as a necessary and primary resource, to exercise their specific purpose. Therefore, the focus of this thesis is to analyze what are the main factors that influenced the exports of explosives manufactured from ammonium nitrate (emulsions), which have the tariff heading (3602002000), during the years 2006 to 2017 To our neighboring country in southern Chile. For this, the research was based on various studies such as Dynamite Market Global Forecast, Global Ammonium Nitrate Explosive Market Size and Industry Trends which detail a set of factors that drive the growth of the explosives market in the world. Likewise, this study is based on a qualitative approach for the determination of the main factors and a quantitative approach for the analysis of the information collected. In a qualitative first stage, it was possible to contrast and identify a series of key factors that directly influenced the exports of Peruvian emulsions, which were obtained from in-depth interviews with specialists dedicated to this area. After the identification of the factors, the data obtained in a second part of the investigation were compared, which is based on a quantitative analysis of the information obtained.
Tesis

Thesis submitted in fulfilment of the requirements for the degree Doctor of Technology: Chemical Engineering in the Faculty of Engineering at the Cape Peninsula University of Technology 2014
This study investigated water-in-oil (W/O) super-concentrated emulsions used as pumpable explosives. The aqueous phase of the emulsions is a supersaturated nitrate salt solution (at room temperature), with a volume fraction of approximately 0.9. Instability of such emulsions arises either from crystallization of the dispersed phase in the system during ageing or under high shear conditions. Here, we report an alternative approach to stabilize this highly concentrated W/O emulsion by adding colloidal particles in combination with short amphiphilic molecules. Thus, the primary goal of this research concerned a phenomenological study of the dependence of surfactant-to-particle ratio as well as the particle hydrophobicity index on stability under high shear in the emulsification process, rheological properties and stability against initiation of crystallization of an internal phase both with ageing and under high shear with a view to optimize the time to the start of crystallization of the emulsion both with ageing and under high shear; to elucidate the mechanism of initiation of crystallization of an internal phase (homogeneous or heterogeneous) and shed light in the stabilization mechanism of the emulsion; to determine how the emulsion formulation content affect pumping characteristics as measured by characteristic rheological parameters. A series of five fumed silica nanoparticles, each with a different hydrophobicity index (HI) in the range of 0.60 – 3, were used in the form of single types of particles as well as binary mixtures. These particles were combined with a low molecular weight conventional surfactant, Sorbitan MonoOleate (SMO), into the oil phase prior to emulsification. It has been found that regardless of the particle hydrophobicity, fumed nanosilica alone cannot form highly concentrated W/O emulsion up to 90 vol%. Moreover, Pickering emulsions are unstable under shear conditions and thus it is difficult to make highly concentrated W/O pumpable emulsion explosives using only fumed nanosilica. The correlation between the refinement time and SMO-to-particle ratio showed a deflection point/transitional point in the stabilization mechanism. Below the transitional point the silica content dominates over SMO. Conversely, above the transitional point the particles have little effect and the SMO dominates. A thermodynamic consideration revealed that in this region only SMO is likely to adsorb at the W/O interface and controls the emulsifying process. As with refinement time, the correlation between the shear modulus and SMO/particle ratio shows a deflection /transitional point which, as before, mark the transition point between regions of particle or SMO domination. Interestingly, it was found that for each HI, the initiation of crystallization is the most delayed, both on shelf life and under high shear, when the emulsion is prepared with an SMO-to-particle ratio equaling exactly the value at this transitional point. Moreover, the research demonstrated that a drastic change in mechanism of initiation of crystallization of the dispersed droplets occurs at the transitional point. Homogeneous nucleation within the droplets is the dominating mechanism of initiation of crystallization of an internal phase for SMO/particle ratios below and at the transitional point. In this case, the relationship between the zero modulus of particle dispersions in oil and the SMO-to-particle ratio demonstrated that the most stable emulsions are formed from the most unstable dispersions, indicating that less repulsion between particles is required to delay the onset of crystallization. This was further corroborated by the linear correlation between the time to the onset of crystallization and the shear modulus of the emulsion. On the contrary, it was found that for SMO/particle ratios above the critical point, heterogeneous nucleation catalyzed at the surface of droplets is the dominating mechanism of initiation of crystallization of nitrate salts in the super-cooled droplets This was found to be consistent with SMO-only system. That is the change in the mechanism of initiation of crystallization originates from a drastic change in the emulsion structure due to excess surfactant was highlighted by the drastic change in the linear correlation between the time to the start of crystallization and the strength of the emulsion structure as measured by the shear modulus. The optimum time to the start of crystallization (onset of crystallization associated with optimum SMO-to-particle ratio) is sensitive to the particle HI; increasing with increase of particle HI. A general correlation between the particle HI and optimum time to the onset of crystallization has been identified and formulated for the whole family of single types and mixtures of fumed nanosilica used in this study.

Muchas filosofías, teorías y estrategias se han desarrollado desde hace varios años con el fin de ofrecer ventajas y beneficios en el desarrollo de operaciones eficientes como son: la planificación de requerimiento de materiales (MRPI y MRPII), la teoría de restricciones (TOC), balance de línea, just in time (JIT), lean manufacturing, entre otras. Asimismo certificaciones internacionales como ISO 9001, ISO 14000. Es así que se plantea el presente trabajo de tesis para proponer la implementación de la filosofía just in time con el fin de elevar la capacidad de producción de una planta de emulsión matriz y mejorar la gestión de los inventarios con el fin de obtener mayor eficiencia, reducción de costos y mejorar el tiempo de respuesta a la demanda de los clientes.
Tesis

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.

Дисертація на здобуття наукового ступеня доктора технічних наук за спеціальністю 05.26.01 – "Охорона праці". – Державний вищий навчальний заклад "Національний гірничий університет". – Дніпропетровськ, 2010.
Диссертация на соискание ученой степени доктора технических наук по специальности 05.26.01 – "Охрана труда". – Государственное высшее учебное заведение "Национальный горный университет". – Днепропетровск, 2010.
The dissertation for the scientific degree of doctor of technical science on speciality 05.26.01 – "Labour protection" – National Mining University, Dnepropetrovsk, 2010.
У дисертації виконано аналіз існуючих емульсійних ВР та систем ініціації зарядів ВР, з точки зору забезпечення безпеки їх виробництва та використання на гірничих підприємствах. Запропоновано структуру системи управління ри-зиками на основі проведення сертифікації промислових ВР на забезпечення технічної й екологічної безпеки при їх виробництві, транспортуванні, зберіганні і застосуванні. Виконано оцінку стійкості хімічних зв'язків між частинками різ-них фаз емульсійних речовин під впливом різноманітних зовнішніх збурень та експериментально досліджено фізичну та хімічну стабільність емульсій з висо-коенергетичними компонентами. Розроблено безпечну промислову технологію виробництва різних модифі-кацій високоенергетичних наливних і незапобіжних патронованих емульсійних ВР марки "ЕРА", які мають високу потужність та низьку чутливість до зовнішніх збурень, є безпечні у поводженні і дозволяють повністю механізувати всі опера-ції з виготовлення і заряджання ВР у свердловини та технологію виробництва елементів неелектричної системи ініціювання зарядів ВР. Створений мобільний автоматизований міні-завод з виробництва високоенергетичних емульсійних ВР, у тому числі з компонентами ТРП, з безпечним технологічним процесом у діапа-зоні температур навколишнього середовища від мінус 35 до плюс 60 С.
В диссертации выполнен анализ существующих эмульсионных взрывча-тых веществ (ВВ) и систем инициирования их зарядов с точки зрения обеспе-чения безопасности при их производстве и использовании на горных предпри-ятиях. Установлено, что увеличение энергетического потенциала ВВ, использо-вания высокоэнергетических компонентов для ВВ, в том числе с продуктами утилизации твердого ракетного топлива (ТРТ), повышает риск возникновения аварий и аварийных ситуаций как при изготовлении так и при использовании ВВ. Предложена структура системы управления рисками на основе проведения сертификации промышленных ВВ на обеспечение технической и экологиче-ской безопасности при их производстве, транспортировке, хранении и приме-нении. Введена дополнительная критериальная оценка факторов безопасности – параметра "эксплуатационного" влияния на сбалансированность структуры и сохранения свойств эмульсионных ВВ. Разработан алгоритм оценки опасности промышленных ВВ, содержащих продукты утилизации ТРТ. Исследовано влияние разнообразных внешних возмущений на стойкость химических связей между частицами разных фаз эмульсионных веществ. Уста-новлены закономерности влияния электрического поля на стойкость этих свя-зей между частицами разных фаз эмульсионных веществ. Исследованы физиче-ские факторы, инициирующие возможные условия взрывного превращения эмульсионных ВВ в процессе газогенерации. Установлены закономерности влияния разнообразных факторов на стойкость разработанных эмульсий. Про-ведены исследования взрывных характеристик, характеристик стабильности и безопасности новых эмульсионных ВВ с добавками энергонасыщенных компо-нентов твердого ракетного топлива. Разработана безопасная промышленная технология и организовано произ-водство разных модификаций новых наливных и непредохранительных патро-нированных высокоэнергетических эмульсионных ВР марки "ЕРА", способных разрушать породы любой прочности и обводненности, которые имеют низкую чувствительность к внешним возмущениям и относительно безопасные при ис-пользовании, что позволяет полностью механизировать все операции из изготов-ления и заряжения ВВ в скважины и технологию производства элементов не-электрической системы инициирующего зарядов ВР. Разработана безопасная тех-нология и организована промышленная утилизация твердого ракетного топлива. Создана безопасная и экономически эффективная технология производства элементов неэлектрической системы инициирования зарядов ВВ с использованием высокоэнергетических продуктов, изъятых из твердого ракетного топлива. Разработана новая неэлектрическая система инициирования зарядов ВВ "Прима-ЕРА", являющейся водостойкой с повышенной безопасностью при производстве, хранении, транспортировке и использовании, и предназначенная для инициирования промежуточных детонаторов и патронов-боевиков. Создан стационарный завод с безопасным технологическим процессом производства высокоэнергетических эмульсионных ВВ производительностью до 60000 т/год. Создано и внедрен экономически эффективный мобильный комплекс, который выполняет все этапы, необходимые для проведения буро-взрывных работ, позволяющий снизить на 15% расход эмульсионных ВВ и на 50% выход мелких фракций горной массы.
The analysis of existent emulsive explosives and systems of initiating charges of explosives, from the point of view providing safety their production and use on mining enterprises is executed in dissertation. The structure of the system control by risks is offered based on conducting certification industrial explosives on providing technical and ecological safety at their production, transporting, storage and application. The estimation of stability of chemical bonds is executed between the particles of different phases of emulsive matters under action various external indignations and experimentally probed physical and chemical stability of emulsions with high-power components. Safe industrial technology of production of different modifications of high-power liquid and unpreventive ward emulsive explosives of brand "ERA", which have high power and low sensitiveness to external indignations, safe in a conduct and allow fully to mechanize all of operations from making and loading of explosives in mining holes and technology of production of elements of the unelectric system of charges initiating of explosives is developed. The mobile automated mini-plant is created from the production of high-power emulsive explosives, including with the components of TRP, with a safe technological process in the range of ambient temperatures from minus 35 to plus 60 С.

The stability of an industrial emulsion explosive comprising a high internal phase water-in-oil emulsion, stabilised by a polyisobutylene based surfactant (PIBSA) was investigated as a function of the oil phase and related parameters. The emulsion was characterised using a small angle and ultra small angle neutron scattering (SANS and USANS) in the size range 10 {u00C5} to 20 ?m using the technique of contrast matching. In addition to the characterisation, solution viscometry experiments were performed to enable the measurement of the surfactant-solvent interaction through the Flory-Huggins constant. In the industrial setting, diesel is used as the oil phase. To enable a systematic study of the effect of the solvent, in addition to diesel, toluene; cyclohexane; and hexadecane were used to approximate the naphthenic, aromatic and aliphatic character of diesel. The solution viscometry experiments showed that the nature of the oil phase has a marked effect on the interaction between the solvent and the PIBSA surfactant. This effect was measured as a change in the Huggins constant as a function of the solvency. Diesel was found to be a theta solvent for PIBSA at 25{u00B0}C. As diesel is the choice of solvent in the industrial setting, this result showed that there is a correlation between the extreme stability of the emulsion and favourable solvent-surfactant interaction. Measurements on toluene, hexadecane, the 50:50 v/v hexadecane:toluene mixture and cyclohexane presented a trend in solvency showing that aromatic character in the solvent diminishes solvent quality as do saturated cyclic compounds (cyclohexane). The structural characterization through neutron scattering revealed the presence of reverse micelles; micron sized aggregates of surfactant; and the behaviour of the PIBSA surfactant at the droplet-oil interface. All of the above were found to be highly sensitive to the nature of the oil phase. The structural and thermodynamic information fit with a depletion stabilization model of emulsion stability. The depletion stabilisation theory enabled the calculation of the depletion potential barrier to coalescence based on the knowledge of the droplet and reverse micelle sizes, and the volume fraction of the reverse micelles. The sensitivity of the emulsion to the nature of the solvent phase was explained in terms of the varying population of reverse micelles as a function of the oil phase and the Huggins constant. As a result of this theory, a clear connection was established between solvent quality and emulsions stability.

Pumpable emulsion explosives have been available to surface and underground massive mining operations for decades and through their unique properties offer significant advantages through improved safety, reliability and performance. Despite their advantageous properties the benefits of pumpable emulsions have been unavailable to narrow reef mining operations due to the void in technology necessary for their successful implementation within the challenging environment. The purpose of the following research report is to evaluate the viability of pumpable emulsion explosives for use in South African narrow reef mining operations. By approaching the problem from multiple perspectives, this research report aimed first to propose a theoretical framework and suite of equipment suitable for the implementation of pumpable emulsions within the narrow reef environment. Through the development of this equipment, controlled tests could be undertaken on the proposed narrow reef emulsion formulations and pumpable emulsion technology to obtain the necessary understanding of the performance of the system under controlled conditions. Once an understanding had been obtained for the controlled performance of the system, a field study could be undertaken in order to compare the performance of the new pumpable emulsion system with available explosives within the underground mining industry. Through the results obtained a comparison could be made of the blasting efficiency and feasibility of pumpable emulsions when compared to existing explosives within the narrow reef environment. Given the vast difference in underground narrow reef and massive mining operations, fundamental changes were necessary with regard to emulsion technology prior to the successful implementation of the narrow reef emulsion system. Following the development of the system, controlled explosives tests allowed for optimisation of the pump technology as well as recommended daily practices. Blast results achieved in field trials with the narrow reef emulsion system allowed for improved blasting efficiency while reducing explosives costs per tonne broken. While blast results and efficiencies improved throughout pumpable emulsion trials, variances in daily blasting practices including the use of stemming, overcharging and varying priming practices influenced the results obtained. Further testing is therefore recommended in order to determine the influence of variables on the results obtained such that a specific increase in blasting efficiency can be determined.

Research Doctorate - Doctor of Philosophy (PhD)
This thesis examines the rates and mechanisms of chemical reactions leading to production of nitrogen oxides during nitrosation reactions and, in particular, those occurring under conditions relevant to the sensitisation of emulsion explosives, where these toxic gases pose a hazard to explosive users. The decomposition of nitrous acid and nitrosyl thiocyanate were identified in the literature review as likely sources of nitrogen oxides during nitrosation reactions and were subjected to detailed experimental and computational studies.

Research Doctorate - Doctor of Philosophy (PhD)
This thesis investigates the employment of spin traps as NOx scavengers to control noxious NOx formation during nitrosation reactions. Most notably, the reaction conditions studied are relevant to the sensitisation of emulsion explosives activated by the chemical gassing, where the formation of these gases can trigger serious respiratory problems to explosives users. Spin traps are widely used by biochemists to detect and measure free radicals such as nitric oxide (NO) in biological systems. The spin trapping reaction involves the addition of a radical to the spin trap, which results in the formation of a complex adduct, detectable by electron paramagnetic resonance (EPR). Intuitively, as a result of the effect of the spin trapping reaction on free radical, these spin traps can potentially play an important role in the development of a new technology to reduce NOx emission. Four aromatic ortho substituted nitroso compounds, 3,5-dibromo-4-nitrosobenzene sulfonate (DBNBS), nitrosobenzene sulfonate (NBS), 3,5-dimethyl-4-nitrosobenzene sulfonate (DMNBS) and 3,5-dichloro-4-nitrosobenzene sulfonate (DCNBS) were subjected to detailed experimental and theoretical investigation in this thesis. These compounds were synthesised by the oxidation of their corresponding amine compounds and characterised by infrared (IR), ultraviolet visible (UV-Vis), nuclear magnetic resonance (NMR) spectroscopy and nanostructured assisted laser desorption ionisation mass spectrometric (NALDI-MS). The thesis initially studied the reaction of DBNBS with NO, where NO was generated in an acidic nitrite solution, conditions which are similar to the chemical gassing process of emulsion explosives, by examining gaseous and liquid products from the reaction. Membrane inlet mass spectrometer (MIMS) analysis disclosed the presence of significant amount of nitrogen gas (N₂) in the gas phase, whereas ion chromatographic analysis of the reaction mixture disclosed elevated amounts of nitrate were formed during the gassing reaction. During the reaction, DBNBS initially reacts with NO to form a short live DBNBS-NO adduct. The release of N₂ is a consequence of the homolytic cleavage of the C-N bond of a diazenyl radical. This assertion is based on quantum chemical calculations (Density Functional Theory) which validates the favourable formation of a diazenyl radical as well as oxygen. The elevated concentration of nitrate in solution provides additional evidence of the presence of oxygen released as a result of the decomposition of the radical intermediate (DBNBS-NO adduct). NALDI-MS analysis of liquid products in the study enabled the identification of 3,4,5-trinitrobenzene sulfonate (MW of 291.888 a.m.u) as the primary product from the reaction, and a number of other nitro compounds were also identified. Analysis of the gaseous and liquid products, in particular the NALDI-MS technique, demonstrates that the presence of nitrite leads to the formation of a competing reaction pathway whereby nitro group is introduced in the aromatic system through the coupling of nitrite with a phenyl radical. A novel membrane NOx analyser and a stopped-flow UV-Vis spectrometer were employed to determine the rate of trapping of NO by DBNBS based on the proposed mechanism. The thermodynamic and kinetic properties of the dissociation of DBNBS dimer to its monomer, were first investigated as this step controls the trapping of NO by DBNBS. An equilibrium constant, Kc of (1.29 ± 0.03) x 10⁻³ (at 25°C) for DBNBS dimer/monomer interchange was estimated, which indicates that, at equilibrium around 20 % of the dissolved DBNBS is present as monomer at room temperature, and available for trapping NO under these conditions. The study of the reaction at temperatures ranging from 25 to 60°C shows increasing monomer equilibrium concentrations as temperature rises. Analysis of the measurements from the ex situ trapping of NO (where nitric oxide was generated via the rapid nitrosation of ascorbic acid) to a multistep reaction mechanism resulted in an estimate of the rate constant kTrap of 165 mol⁻¹ dm³ s⁻¹. In contrast, the net rate of trapping was considerably lower with a value of 4.7 mol⁻¹ dm³ s⁻¹ for the in situ reaction of DBNBS with NO, where NO is formed via the slow decomposition of nitrous acid. The physicochemical properties of the four selected aromatic ortho substituted nitroso compounds were also examined. Since the four nitroso compounds exist in a monomer-dimer equilibrium with only the monomeric form behaving as a free radical scavenger, thermodynamic analysis of the dimer-monomer equilibrium was undertaken using UV-Vis spectrophometer. The reactivity of the aromatic ortho substituted nitroso compounds towards NO was investigated, to determine the effect of substituents on the aromatic ring towards trapping efficiency in an aqueous system. The production of nitrogen gas and an elevated quantities of nitrate were observed during the reactions of nitroso compounds with NO suggesting that the homolytic cleavage of aryl radicals generally occurs when nitroso compounds reacts with NO as proposed previously for DBNBS. The capacity of the aromatic nitroso sulfonates was investigated at ammonium nitrate (AN) concentration ranging from 0 to 7.5 mol dm⁻³ for trapping NO. The solubility of DCNBS in AN solutions was the most affected among the four compounds and was reflected by a notable decrease in the efficiency of NO removal by the compound with increasing AN concentrations. Experiments in AN explosive established that chemical trapping of NO was more efficient when the nitroso compounds were added at the time of chemical gassing, rather than being part of the discrete phase of the emulsion. All nitroso compounds demonstrated an inhibitory effect on the amount of NO released from the chemical gassing of the emulsion explosive. Owing to the reduced efficiency in NO removal in AN solutions and AN emulsion, aromatic nitroso sulfonates are good NO scavengers with removal efficiency in NO of up to 70 % that can be achieved in sensitised AN emulsion.

Dissertação de Mestrado Integrado em Engenharia Mecânica apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra.
A realização deste trabalho focou-se no estudo da influência de alguns parâmetros de soldadura por explosão, como o tipo e rácio de explosivo e o tipo de base de suporte, na morfologia, microestrutura e comportamento mecânico de soldaduras de cobre a alumínio, obtidas para uma configuração plana. Para o efeito foram realizadas soldaduras em configuração plana, utilizando 4 diferentes tipos de explosivos (CD, ANFO, Eex+MEOV, Eex+EPS) e diversos rácios de explosivo (entre 1 e 3), entre ligas de alumínio e cobre. Foi analisada a morfologia, a microestrutura e resistência mecânica das soldaduras, com recurso a microscopia óptica e electrónica de varrimento, ensaios de microdureza e de tracção, usando extensometria óptica. Foi também variada a configuração da base de suporte da placa estacionária. Além disso foram analisadas as soldaduras obtidas em anos anteriores e comparadas com as actuais. Resultados mostraram que o efeito da variação de cada um dos parâmetros foi visível, principalmente na morfologia e nas propriedades mecânicas obtidas. A velocidade de detonação (Vd), para um mesmo rácio de explosivo, variou consoante o tipo de explosivo usado. O aumento da velocidade no ponto de colisão (Vc) está associada à redução do ângulo de colisão . O aumento da velocidade de impacto (Vp) conduz o aumento do ângulo de colisão  A ondulação tende a crescer em termos de comprimento e amplitude com o aumento da Vp. Valores de dureza obtidos foram superiores para as bases que apresentavam maior rigidez. O aumento do rácio de explosivo conduziu à maior espessura das zonas fundidas e de uma maior presença de compostos intermetálicos, fissuração e cavidades. Ensaios mecânicos efectuados mostraram que a ligação foi mais resistente que um dos materiais base, rompendo sempre neste numa zona afastada da soldadura.
The realization of this paper is focused on the study of the influence of some parameters of welding by explosion, such as the type and ratio of explosive and the anvil support on the morphology, micro-structure and mechanical behavior of copper and aluminum welding, obtained for a flat configuration. For this effect several welding’s on a flat configuration were realized, using several types of explosives (ANFO, Eex+MEOV, Eex+EPS) and several explosive ratios (between 1 and 3), for aluminum and copper alloys. The morphology was analyzed, the micro-structure and mechanical resistance of the welding’s, using microscopic optical and electronic sweeping, microhardness rehearsals and traction, using optical extensometer. The anvil of the flat stationary plate was also varied. The welding’s obtained in previous years were also compared to current samples. Results showed that the effect of the variation of each parameter was visible, specifically in the morphology and mechanical properties obtained. The detonation velocity (Vd), to the same ratio of the explosive, varied according to the type of explosive used. The increase of speed at the collision point leads to the reduction of the collision angle β. This increase of the impact velocity (Vp) leads to the increase of the angle of collision β. The curling tends to increase in terms of length and amplitude with the increase of Vp. Hardness values obtained was superior to the bases that presented with higher hardness. The increase in the ratio led to a larger thickness of the melted zones, cracking and cavities. Mechanical rehearsals done showed that the connection was more resistant than any base materials, ripping always in an area away from the welding.

As emulsões explosivas, devido à sua composição, diferenciam-se dos restantes explosivos civis visto que, para além do seu elevado desempenho e custo competitivo, apresentam um nível de segurança no fabrico e aplicação, que mais nenhum explosivo consegue garantir atualmente. A competitividade é o principal desafio enfrentado pelas empresas no seu dia-a-dia, mas é também a grande motivadora para a inovação, levando à constante necessidade de desenvolvimento e melhoria de produtos. Com vista à otimização dos produtos e redução de custos, foram realizados testes para avaliar alterações quer no sensibilizante, quer na solução oxidante utilizadas. Assim como, com o objetivo de satisfazer as necessidades dos clientes, foram testados novos produtos desenvolvidos para aplicação em pré-corte, uma emulsão encartuchada contendo cordão detonante e, para aplicações subterrâneas, uma nova gama de emulsão bombeada. Foram preparadas em laboratório várias formulações de emulsões explosivas a fim de verificar as suas características e propriedades, sendo as mais relevantes para o desempenho do explosivo, a sensibilidade e a velocidade de detonação. Dos testes realizados com o sensibilizante concluiu-se que este parâmetro já se encontra otimizado, não sendo possível utilizá-lo para a redução de custos. Quanto aos testes com as novas soluções oxidantes concluiu-se que as suas composições não se adequam ao fabrico de emulsões explosivas. Quer para as emulsões bombeadas testadas, quer para o produto para aplicação em pré-corte conseguiram-se verificar as características necessárias para a sua aprovação e comercialização.
Emulsion explosives differentiate from other civil explosives due to their composition. In addition to the high performance and competitive cost, they present a level of safety in the manufacture and application, which no other explosive can guarantee nowadays. Competitiveness is the main challenge faced by companies on a daily basis, but it is also the great motivator for innovation. This leads to the constant need for product development and improvement. To optimize products and reduce costs, tests were carried out to evaluate changes in both the sensitizer and the oxidant solution used. Also, to meet customers' needs, new products were developed for pre-cutting - a packaged emulsion containing detonating cord, and for underground applications - a new range of bulk emulsion, were tested. Several formulations of emulsion explosives were prepared in the laboratory in order to verify their characteristics and properties, being the most relevant for the performance of the explosive, the sensitivity and the velocity of detonation. From the tests carried out with the sensitizer it was concluded that this parameter is already optimized and cannot be used to reduce costs. As for the new oxidizing solutions tests, it was concluded that their compositions are not suitable for the manufacture of explosive emulsions. For both the bulk emulsions and the product for pre-cut application tested, the characteristics necessary for its approval and commercialization were verified.

Dissertação de Mestrado Integrado em Engenharia Mecânica na especialidade de Produção e Projeto, apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra.
Este trabalho teve como objetivo principal a análise de juntas soldadas utilizando o método de soldadura por explosão (EXW) entre chapas de alumínio, cobre e alumínio-cobre, e a influência da variação de alguns parâmetros de soldadura na qualidade da interface de soldadura. Foram efetuadas para o efeito 6 ensaios experimentais, sendo dois deles entre placas do mesmo tipo de material (Al-Al e Cu-Cu) e os restantes quatro entre alumínio e cobre, sendo projetado o alumínio, contrariamente aos ensaios realizados noutros anos, onde o material projetado foi o cobre. Utilizaram-se dois tipos de emulsões explosivas de nitrato de amónio, umas sensibilizada com microesferas ocas de vidro (Eex+MEOV) e outras sensibilizadas com esferas de esferovite (Eex+EPS), com variados valores de rácio de explosivo. A emulsão Eex+EPS apresentou uma detonação mais heterogénea e uma velocidade de detonação Vd mais baixa, o que origina uma morfologia na interface também mais heterogénea e uma maior formação de compostos intermetálicos. Para as duas emulsões verificou-se uma maior adesão do alumínio ao cobre utilizando o rácio mínimo de explosivo, no entanto mesmo assim não ocorreu a ligação. Levanta-se a questão entre valores utilizados na construção da janela de soldabilidade no que consta ao cobre, pois apesar de a soldadura se localizar fora da janela de soldabilidade, apresentou bons resultados em termos de aspeto da interface, microdureza e ensaios de tração/corte. A configuração alumínio-cobre apresentou uma janela de soldabilidade muito reduzida, devido maioritariamente à baixa temperatura de fusão do alumínio. Nenhuma das soldaduras Al-Cu foi bem-sucedida, mesmo utilizando os rácios mínimos de explosivo. Conclui-se que as emulsões explosivas utilizadas não são adequadas para este tipo de ensaios, pois é necessário um rácio de explosivo mais reduzido para se conseguir respeitar os parâmetros definidos pela janela de soldabilidade. Observou-se que em soldaduras similares, isto é entre o mesmo tipo de material as maiores durezas são observadas na placa voadora e não na interface. Verificou-se que o aumento do rácio de explosivo R conjuntamente com variações na velocidade de detonação conduz ao aumento da velocidade de impacto Vd, que por sua vez leva ao aumento do ângulo de colisão B.
The main goal of this research was the analysis of the effect of welding parameters on the quality of similar welds aluminum-aluminum and copper-copper and dissimilar welds aluminum-copper, using the explosive welding method (EXW); the influence of some welding parameters in the morphology of the welded interface was analyzed. Six experimental tests were made, four of them between aluminum-copper, being the aluminum projected against the copper plate. Two types of explosive were used, Eex+MEOV and Eex+EPS, with several explosive ratios. The values used for the copper-copper weldability window definition were analyzed, because although the welding was located outside the window, this welding had very good results in terms of interface aspect, hardness and tensile/shear tests. The aluminum-copper weldability window is very small, which is mainly a consequence of the aluminum low temperature melting point. None of the four aluminum-copper weldings were successful, even using the minimum explosive ratio. It’s concluded that the used explosive types are not the right ones for the aluminum flyer. The similar welds, where the same material was used in the flyer and the parent plate, showed an increased hardness in the flyer plate side. It was observed that an increase in the explosive ratio R leads to an increase in the impact velocity Vp, which leads to an increase in the collision angle B.

Dissertação de Mestrado Integrado em Engenharia Mecânica apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra.
As operações de detonação submarinas têm sido, durante as últimas décadas, alvo de pesquisa e desenvolvimento das operações de detonação marítimas, incluindo testes de torpedo, bem como, em testes em piscinas para a medição de energia de detonação de explosivos industriais. O estudo dos geradores de demolição por carga submersa (WBWG) tiveram por base nestes conceitos. Com o presente trabalho pretendo apresentar o estudo do comportamento de WBWG, com base em dois tipos de recipientes de plástico com água (25 litros e 1000 litros), contendo no seu interior exactamente no centro um detonador dentro de uma carga explosiva cilíndrica. As cargas explosivas usadas foram uma emulsão de nitrato de amónio com fuel oil (ANFO) e cordão detonante (12 g/m) de pentrite (PETN). Muito resumidamente uma revisão bibliográfica foi realizada. As propriedades de detonação dos explosivos foram previstas utilizando um programa termoquímico, designado por THOR. Para a expansão dos produtos de detonação dos explosivos foi aplicado uma equação de estado JWL. Foi realizado uma revisão aos conceitos fundamentais desta equação e os seus coeficientes foram determinados e optimizados correlacionando as previsões do THOR e a equação de estado (EOS) JWL para a mínima diferença através de uma função quadrática auxiliar. Por forma a calcular os coeficientes de JWL um novo método foi usado. Este baseia-se na evolução das curvas adiabáticas e isentrópicas obtidas pelo THOR, utilizando uma função do Microsoft Excel ® Solver, assumindo algumas suposições para o coeficiente Grüneisen (a partir do exponencial da curva adiabática; do exponencial da curva isentrópica para um volume adimensional limite; do exponencial da curva isentrópica para todos os valores da expansão, e por último; deduzido por Handley, 2011). Os melhores resultados obtidos foram pela utilização do coeficiente Grüneisen do exponencial da curva isentrópica para todos os valores da expansão, onde para a emulsão de ANFO e para PETN. As dimensões e o design da configuração de “WBWG” experimental foram apresentadas, juntamente com a descrição de uma experiência de detonação tipo utilizando 3 g de PETN (detonador No.8 mais 2.4 g de cordão detonante de PETN). Foi realizada uma simulação a 2D e 3D de “WBWG” usando o programa Autodyn para um contentor de metro cúbico cheio de água (1000 litros) para ambos os explosivos. Os resultados obtidos mostram a possibilidade de ter este tipo de cargas explosivas sem a destruição do “WBWG” contentor. Uma vez que, os níveis de pressão na água, perto das paredes plásticas, sob a maior carga admissível, ronda os 6 MPa. Foi sempre possível observar a deformação elástica das paredes do contentor, as reflecções do choque subaquático, alterando a sua forma cúbica original para uma espiral transiente. Adicionalmente os procedimentos executados para o THOR, para o Microsoft Excel ® Solver e para a interface do programa de simulação Autodyn “material input data” foram apresentados.
Underwater blasting operations have been, during last decades, subject of research and development of maritime blasting operations, including torpedo studies. Aquarium tests, for the measurement of blasting energy of industrial explosives, are based in studies of confined underwater blast wave generators (WBWG). The current work present the study of the behavior of WBWG, based in two different water plastic containers (25 litres and 1000 litres), having in the center a detonator inside a cylindrical explosive charge. The explosive charges used were ammonium nitrate with fuel oil (ANFO) emulsion and pentaerythritol tetranitrate (PETN) detonating cords (12 g/m). Summarily the theoretical background was review. The explosives detonation properties were predicted using a thermochemical computer code, named THOR. For the expansion of the detonation products of the explosives was applied JWL EoS. JWL fundamentals were review and his parameters were determined and optimized correlating THOR predictions and JWL EoS to a minimum difference with an auxiliary quadratic function. In order to calculate the JWL coefficients, a new numerical method was used. It was based in the evolution of adiabate and isentrope curves, obtained by THOR code, using a function of the Microsoft Excel ® Solver, assuming a few assumptions for Grüneisen coefficient (from the exponential of the adiabatic curve; from the exponential of the isentrope curve at a limit adimensional volume; from the exponential of the total expansion of isentrope curve and, at last; deducted from Handley, 2011). The best results were obtained using the Grüneisen coefficient from the exponential of the total expansion of isentrope curve, which were for ANFO emulsion and for PETN. The dimensions and design configurations of the experimental WBWG were presented and also a blast type experiment for 3 g of PETN (detonator No. 8 plus 2.4 g charge of PETN detonation cord) was described. Autodyn 2D and 3D simulations of WBWG were performed using a cubic meter water container (1000 litres) for both explosive. The obtained results show the possibility of having these explosive charges without destruction of WBWG containers. Since water pressure levels, close to plastic walls, under maximum admissible charges, are closed to 6 MPa. It was always observed the elastic deformation of containers wall, under the water shock reflections, changing from its original cubic shape to a transient spherical one. Additionally the execution procedures of THOR code, Microsoft Excel ® Solver and the interface of Autodyn simulations material input data was presented.

Dissertação de Mestrado em Engenharia Mecânica na especialidade de Produção e Projeto apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra.
O Alumínio e o Aço são dos materiais mais utilizados industrialmente. Cada um apresenta propriedades extremamente úteis, o Alumínio tem elevada resistência à corrosão e baixa densidade, e o Aço possui elevada resistência mecânica, elevada resistência a altas temperaturas e, para o caso do Aço Inoxidável, alta resistência à corrosão também. Devido à elevada diferença entre as suas temperaturas de fusão, a combinação destes dois materiais por processos de soldadura por fusão, ditos convencionais, é impossível. O objetivo deste trabalho é iniciar o estudo da ligação destes dois materiais através do processo de soldadura por explosão. Já era conhecida a dificuldade de obter ligação entre estes dois materiais através da configuração plana convencional. Ainda assim, tratando-se de uma primeira abordagem, foi a configuração utilizada para perceber as dificuldades existentes na ligação destes dois materiais. Foi construída a Janela de Soldabilidade, para ligação similar Alumínio-Alumínio e dissimilar Alumínio-Aço, para melhor preparar as condições experimentais. Foram realizados cinco ensaios, onde o Alumínio foi sempre o material projetado. Em dois destes ensaios foi obtida ligação entre as placas, ainda assim, uma ligação de baixa resistência. Apenas um dos ensaios se localizou dentro da Janela de Soldabilidade mas não apresentou ligação. Foi dado maior enfase ao estudo da ligação dissimilar Alumínio-Ferro. Foram utilizadas três composições de explosivo. A composição apenas de ANFO, sigla para Ammonium Nitrate Fuel Oil, não apresentou uma detonação completa e apresentou a menor velocidade de detonação. As outras composições, (ANFO+Eex) e (ANFO+(Eex+DE)), sendo Eex a abreviatura para emulsão explosiva e DE a designação para micro-esferas ocas de polímero, apresentaram detonação homogénea, registando-se a maior velocidade de detonação para a composição (ANFO+(Eex+De)). Apenas nos ensaios onde se utilizaram as composições ANFO e (ANFO+Eex) se obteve ligação. Ainda assim, nenhuma das composições utilizadas é ótima para o resultado final pretendido, uma soldadura por explosão com qualidade. Verificou-se que o aumento do Rácio de explosivo conduz ao aumento da velocidade de impacto e, por conseguinte, também ao aumento do ângulo de colisão. Com o aumento do Rácio de explosivo aumenta também a quantidade de compostos intermetálicos na zona da interface entre as placas e também a dureza final das placas que colidem.
Explosion Welding is an effective method of joining various metals and alloys. The aim of this research is to initiate the study of dissimilar weld aluminum-stainless steel, AA 6082-T6 - AISI 304, and analyze the influence of the welding parameters on the final result using this method. Also an analysis has been made for similar weld aluminum-aluminum. The Weldability Window was studied for the two kinds of joints. Five experimental test were made, always being used aluminum as the flyer plate. Three explosive compositions were tested. The first one had only Ammonium Nitrate Fuel Oil (ANFO), the second one was a ammonium nitrate-based emulsion with ANFO, and the third one was composed of a ammonium nitrate-based emulsion with ANFO and hollow polymer microballons as a sensitizing agent. These compositions didn’t give good results. All the results obtained show that increasing the explosive ratio, increases the impact velocity of the flyer, and, in consequence, also the collision angle increases. A larger quantity of intermetallic compounds on the interface and a higher final hardness on the colliding plates is also observed with the increase of explosive ratio.