Dissertations / Theses on the topic 'Blast Environments'

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 52-53).
Military commanders in austere environments often face challenges in setting up headquarters buildings that offer protected areas for sensitive equipment. One solution to this problem is simply to build a structure that can be used for this purpose. This method can prove to be difficult in that it could either require large amounts of prefabricated concrete, heavy earthmoving equipment, or a significant effort in digging by hand. Clearly, all of these options are unsuitable for constructing a headquarters building that would be occupied for a short time or if the resources required were unavailable. Another solution to this problem is to simply occupy an existing structure. This method is extremely favorable with respect to resources required; with the major drawback being that at times existing structures may offer limited protection from hostile forces. Since the US Army often has overwhelming firepower when compared to contemporary threats, many times hostile forces will resort to suicide or remotely detonated explosive devices when attempting to destroy or damage structures of this type. In order to determine the feasibility of mitigating this threat, this paper will explore the effects of various explosive devices on model building types that may be found in austere environments, and explore the effects of possible reinforcement schemes in mitigating blast threats to these structures.
by Andrew J. Maxa.
S.M.

Dans cette recherche, un modèle de propagation d'ondes de choc sur grandes distances sur un environnement urbain est construit et validé. L'approche consiste à utiliser l'Equation Parabolique Nonlinéaire (NPE) comme base. Ce modèle est ensuite étendu afin de prendre en compte d'autres effets relatifs à la propagation du son en milieu extérieur (surfaces non planes, couches poreuses, etc.). La NPE est résolue en utilisant la méthode des différences finies et donne des résultats en accord avec d'autres méthodes numériques. Ce modèle déterministe est ensuite utilisé comme base pour la construction d'un modèle stochastique de propagation sur environnements urbains. La Théorie de l'Information et le Principe du Maximum d'Entropie permettent la construction d'un modèle probabiliste d'incertitudes intégrant la variabilité du système dans la NPE. Des résultats de référence sont obtenus grâce à une méthode exacte et permettent ainsi de valider les développements théoriques et l'approche utilisée

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2004.
"June 2004."
Includes bibliographical references (leaf 45).
Blast design is a necessary part of design for more buildings in the United States. Blast design is no longer limited to underground shelters and sensitive military sites, buildings used by the general public daily must also have satisfactory blast protection. Integrating blast design into existing norms for structural design is a challenge but it is achievable. By looking at the experience of structural designers in Israel over the past several decades it is possible to see successful integration of blast design into mainstream buildings. Israel's design techniques and policies can be used as a paradigm for the United States. A structural design for a performing arts center is analyzed within the context of blast design. Improvements in the design for blast protection are suggested. These design improvements include camouflaging the structural system, using blast resistant glass, reinforced concrete, and hardening of critical structural members. It is shown that integration of blast design into modem mainstream structures is achievable. New techniques and creative problem solving must be used to adapt blast design to work alongside current design trends.
by Tamar S. Kieval.
M.Eng.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2008.
Includes bibliographical references (leaves 42-44).
Mitigating the energy created from a blast has been a topic of utmost importance in the terrorism-feared world of today. Main targets of concern are passageways that are significant to a specific area, such as bridges. These structures are expensive to construct and vulnerable to explosive loads which is why a cost-effective means of blast mitigation must be researched. There are many aspects of bridges that could be damaged when a blast load is applied. These susceptible areas can be strengthened using new-age, high-strength composite materials to ensure the security of the whole structure. These materials are able to sustain larger loads while dissipating higher amounts of energy when compared to conventional building materials. As a result, the response of the entire structure will be minimized when a blast load is applied. Despite the fact that these composites cost more than typical materials, the increase in project cost could be minimized by limiting the use of these high-strength materials for only the critical areas of the bridge. Other cost effective solutions to blast mitigation occur in the preliminary design phase. Eliminating all pressure-amplifying areas would save members and connections should a blast occur. Also, designing a bridge with high vertical clearances above areas of excessive boat traffic would also minimize the resultant forces and stresses from an explosion.
by Austin DeRogatis.
M.Eng.

Ferramentas BLAST são normalmente utilizadas para efetuar comparações entre sequências de DNA, RNA e proteínas. No entanto, face ao crescimento exponencial das bases biológicas, existe uma preocupação quanto ao desempenho do BLAST, mesmo considerando os equipamentos de grande capacidade computacional hoje existente. Considerando tal fato, algumas ferramentas capazes de executar o BLAST em ambientes distribuídos, tais como clusters e grids, vêm sendo desenvolvidas de modo a acelerar consideravelmente a sua execução. No entanto, até o presente momento, não foi constatado, na literatura existente, nenhum estudo com o objetivo de comprar o desempenho entre essas ferramentas. A avaliação de desempenho dessas ferramentas é normalmente efetuada de forma isolada, considerando apenas o tempo de execução (elapsed time), em situações diversas, como, por exemplo, variando o número de nós em que a ferramenta BLAST é executada.. Almejando uma investigação mais detalhada, principalmente no que diz respeito a avaliação de desempenho do BLAST em ambientes distribuídos, a presente dissertação tem como um dos seus objetivos efetuar um estudo detalhado sobre como comparar o desempenho do BLAST em um ambiente distribuído, considerando para tal, a avaliação de três ferramentas BLAST, dentre elas balaBLAST, desenvolvida no Laborátorio de Bioinformática da PUC-RIO. O segundo objetivo é verificar a eficácia do balanceamento de carga efetuada pela ferramenta balaBLAST.
BLAST tools are typically used to make comparisons between sequences of DNA, RNA and proteins. However, given the exponential growth of the biological databases, there is concern about the performance of BLAST, even considering the equipment of large computing power that exists today. Considering this fact, some tools to run BLAST in distributed environments such as clusters and grids, have been developed to greatly accelerate its performance. However, until now, has not been found in existing literature, no study in order to compare the performance between these tools. The performance evaluation of these tools is usually done in isolation, considering only the execution time (elapsed time) in different situations, for example, varying the number of nodes in the tool BLAST runs. Craving a more detailed investigation, especially with regard to performance evalution of BLAST in distributed environments, this dissertation has as one of your goals make a detailed study to compare the performance of BLAST in a distributed enviroment, considering for such the evaluation of three tools BLAST, among them the balaBLAST developed in the Bioinformatics Laboratory of PUC-Rio. The second objective is to verify the effectiveness of load balancing performed by the tool balaBLAST.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2011.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 54-55).
The social and political climate of the modern world has lead to increased concern over the ability of engineered structures to resist blast events which may be incurred during terrorist attacks. While blast resistance design has been prominent for years in the industrial and military setting, it is starting to gain importance for structures which have been traditionally designed for aesthetics and which have high occupancy density. In these situations it is important that not only materials but the geometry of the building be optimized to reduce the effects of such an attack. However, designing a structure only for prescribed code requirements does not necessarily give a prediction of the post-blast behavior of the structure. Similar to the use of performance-based engineering for seismic events, the effects on a structure designed for blast loading should not be speculative but rather should exhibit expected behavior which is appropriate for the parameters of the given blast. Accounting for uncertainty of a potential blast event by assessing the structure in a probabilistic approach may lead to a more prudent and predictable assessment of damage and loss for the owner. The work herein attempts to provide an overview of the precedent of use of probabilistic methods in structural engineering, the current state of practice in blast engineering and set forth a framework and example by which probabilistic methods may be extended to blast considerations.
by Andrew Nicholas Gillis.
M.Eng.

Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.
Includes bibliographical references (leaves 117-121).
by Ravindra K. Sarma.
M.Eng.

Thesis (Mechanical Engineer and M.S. in Mechanical Engineering)--Naval Postgraduate School, June 2003.
Thesis advisor(s): Young S. Shin. Includes bibliographical references (p. 161-162). Also available online.

A research study has been conducted to simulate liquefaction in saturated sandy soil induced by nearby controlled blasts. The purpose of the study is to help quantify soil characteristics under multiple and consecutive high-magnitude shock environments similar to those produced by large earthquakes. The simulation procedure involved the modeling of a three-dimensional half-space soil region with pre-defined, embedded, and strategically located explosive charges to be detonated at specific time intervals. LS-DYNA, a commercially available finite element hydrocode, was the solver used to simulate the event. A new geo-material model developed under the direction of the U.S. Federal Highway Administration was applied to evaluate the liquefaction potential of saturated sandy soil subjected to sequential blast environments. Additional procedural enhancements were integrated into the analysis process to represent volumetric effects of the saturated soil's transition from solid to liquid during the liquefaction process. Explosive charge detonation and pressure development characteristics were modeled using proven and accepted modeling techniques. As explosive charges were detonated in a pre-defined order, development of pore water pressure, volumetric (compressive) strains, shear strains, and particle accelerations were carefully computed and monitored using custom developed MathCad and C/C++ routines. Results of the study were compared against blast-test data gathered at the Fraser River Delta region of Vancouver, British Columbia in May of 2005 to validate and verify the modeling procedure's ability to simulate and predict blast-induced liquefaction events. Reasonable correlations between predicted and measured data were observed from the study.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2009.
Includes bibliographical references (leaf 44).
In recent years, concern has risen drastically regarding the suitability of structural design for blast resistance. Historic events have proven that buildings that are designed in compliance with conventional building codes are not necessarily able to resist extreme loads, particularly blast loads. While significant progress has been made towards the development of design guidelines for federal buildings according to threat level, comprehensive codes have not yet been devised for blast hardening of non-federal buildings. One of the most important considerations in the strength-based design of buildings is adequate protection against progressive collapse in any unforeseen event. In the past, this has been achieved to a limited extent through exterior barriers, which help thwart efforts to directly impact the building, and thus minimize damage. With the emergence of structural design for blast resistance, methodologies to inhibit progressive collapse can expand to not only comprise exterior components, but also the structural components themselves. This thesis outlines potential structural and architectural techniques to design and retrofit buildings for resistance to blast impact loads as well as progressive collapse. These considerations are then applied to the study of two well-known blast events, the 1995 bombing of the Alfred P. Murrah Building in Oklahoma, and the 2001 attack on the Pentagon. A comparison of the two cases reveals that the redundant and ductile design of the Pentagon provided considerable resistance to impact loads, and contributed greatly to impeding the onset of progressive collapse.
(cont.) Several blast-resistant features found in the Pentagon were not present in the design of the Murrah Building, thereby increasing the vulnerability of the structure to damage and collapse. The development of design codes and guidelines for blast resistance presents a number of challenges. These challenges generally arise from the erratic nature of blast loads and the difficulty in standardizing design procedures for variable levels of threat. While it may be difficult to implement general guidelines and codes for blast resistance, existing knowledge of blast hardening techniques can be applied to the design of buildings on a risk-based, case-by-case basis.
by Isabel Abbott Galvão Sobreira Lopes.
M.Eng.

An explosion is characterized as a sudden release of large energy over a very short duration. As the blast wave travels parallel to a surface, it creates a side-on pressure and when it hits a surface perpendicularly or at an angle, it creates a reflected pressure. Side-on pressure and reflected pressure are much higher than service loads for the structure. Thus, when a blast happens near a building that is not designed to withstand blast loads, it can cause catastrophic damage. The objective of this study is to present a formulation for the design optimization of framed steel structures subjected to blast loads. Also, a formulation is presented for the design optimization of structures that can withstand some possible damage due to blast loads. To this end, an optimization procedure that includes definitions of design variables, cost function, constraints, and structural analyses is discussed. The design variables for beams and columns are the discrete values of the W-shapes selected from American Institute of Steel Construction (AISC) tables. The optimization problem is to minimize the total structural weight subjected to AISC strength requirements and blast design displacement constraints. Linear static, linear dynamic, and nonlinear dynamic analyses are incorporated in the optimization process and optimum designs are compared. Due to design variables and some constraints discontinuity, gradient-based optimization algorithms cannot be used to solve the optimization problem. Therefore, metaheuristic algorithms are used that require only simulation results to solve problems with discrete variables and non-differentiable functions. Since the number of simulations and robustness to obtain good designs are important for the class of problems discussed in this research, a new hybrid optimization algorithm based on Harmony Search (HS) and Colliding Bodies Optimization (CBO) is developed and examined. The algorithm is named Hybrid Harmony Search - Colliding Bodies Optimization (HHC). Also, a novel design domain reduction technique is incorporated in HHC. Some benchmark discrete variable structural design problems are used to evaluate HHC. In comparison with some popular metaheuristic optimization algorithms, HHC is shown to be robust, effective, and needs fewer structural analyses to obtain the best designs. Depending on the size of the structure to be designed, optimization of structures that require linear or nonlinear dynamic analyses using metaheuristic algorithms can be computationally expensive because these types of algorithms need large number of simulations to reach good designs. Equivalent Static Loads (ESL) approach, which has been used for optimization of structural systems subjected to dynamic loads using gradient-based algorithms, is examined for optimization of structures that have discrete design variables using metaheuristic algorithms. The proposed approach is named global optimization with equivalent static loads (GOESL). Solution of four numerical examples shows that GOESL can drastically reduce the number of dynamic analyses needed to reach the best design compared to an algorithm without the ESL approach. However, the ESL step alone cannot converge to the best design for the current formulation, even with many ESL cycles. Therefore, after a few ESL cycles, the procedure may switch to the original algorithm without the ESL cycles to improve designs further. HHC and GOESL are used to solve three-dimensional framed steel structures subjected to blast loads with linear and nonlinear dynamic analyses as separate solution cases. The source of the blast loads is a car carrying 250 lbs of Trinitrotoluene (TNT) with 50 ft standoff distance from the front face of a 4-bay x 4-bay x 3-story building. Optimum designs of the structure to withstand blast loads show that penalty on the optimum structural weight is substantial when linear dynamic analysis is used. With nonlinear dynamic analysis, the penalty on the structural weight is substantially reduced. When the stiffness of the walls is included in the analysis model, there is very little penalty on the optimum structural weight with linear or nonlinear dynamic analysis models. The best designs obtained with the linear and nonlinear dynamic analysis models are checked for some possible damages due to a blast. Two types of damage conditions are defined: (i) complete removal of some key members from the analysis model, and (ii) reduction of stiffness of some members. It is shown that the best designs using linear or nonlinear dynamic analyses can withstand all damage conditions. Thus, resilience of the designs to withstand blast loads is observed.

Thesis: M. Eng., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, May, 2020
Cataloged from the official PDF of thesis.
Includes bibliographical references (pages 99-100).
As the built environment becomes more complex, designers must consider extreme loading when it is necessary to anticipate structural response to rare hazards in addition to the expected loading conditions associated with intended use of a structure. Designing structures to withstand blast loading events can often lead to unnecessary excess material usage. This thesis presents a process of design space exploration utilizing a single degree of freedom analysis for fixed-fixed reinforced concrete beams and one-story single bay reinforced concrete frames subjected to blast loading. This process is used to help understand the relationship between mass, ductility, robustness, and dynamic shear, which are referred to as design objectives for each system. In particular, the effects of geometry, steel reinforcing ratio, and standoff distance are explored to understand their impact on the behavior of each system. Understanding the design space by relating the design objectives, loading characteristics, and structural properties can aid in focusing protective design in the preliminary stages to achieve more efficient designs that ensure safety while minimizing added mass
by Brian T. Luster.
M. Eng.
M.Eng. Massachusetts Institute of Technology, Department of Civil and Environmental Engineering

Thesis: M. Eng. in High-Performance Structures, Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2015.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages [67]-[68]).
Well-publicized intentional and accidental explosions in the last two decades have exposed the lack of resilience in structures triggering disproportionate failure. This has fuelled change in the civil engineering industry with government agencies leading the way. This research further contributes to the topic of blast resistant design with particular focus placed on the response of building structures subjected to external blasts. A software tool to assess the response of structure to blast loads is firstly presented. The proposed tool integrates a staged process and can broadly be broken down into three core modules: the blast load condition, the response of the target structural element(s), and frame stability in the event of a support being compromised. By automating this process, the resistance of a building can be investigated under a number of possible blast situations in quick succession. In addition, the application incorporates a design feature that sizes 2D moment frames for wind and gravity loading, for the sole purpose of studying blasts on different frame strengths and geometries. The latter stages of the report demonstrate the capabilities of the tool by firstly proposing standard input metrics based on industry norm, and following on from this exploring the effects of each input through a parametric analysis. Example input parameters include blast weight, standoff distance, wind speed, number of bays & stories, target column location and element plastic limits.
by Killian T. O'Leary.
M. Eng. in High-Performance Structures

Deep foundations like auger-cast piles and drilled shafts frequently extend through liquefiable sand layers and bear on non-liquefiable layers at depth. When liquefaction occurs, the skin friction on the shaft decreases to zero, and then increases again as the pore water pressure dissipates and the layer begins to settle, or compact. As the effective stress increases and the liquefiable layer settles, along with the overlaying layers, negative skin from the soil acts on the shaft. To investigate the loss of skin friction and the development of negative skin friction, soil-induced load was measured in three instrumented, full-scale auger-cast piles after blast-induced liquefaction at a site near Christchurch, New Zealand. The test piles were installed to depths of 8.5 m, 12 m, and 14 m to investigate the influence of pile depth on response to liquefaction. The 8.5 m pile terminated within the liquefied layer while the 12 m and 14 m piles penetrated the liquefied sand and were supported on denser sands. Following the first blast, where no load was applied to the piles, liquefaction developed throughout a 9-m thick layer. As the liquefied sand reconsolidated, the sand settled about 30 mm (0.3% volumetric strain) while pile settlements were limited to a range of 14 to 21 mm (0.54 to 0.84 in). Because the ground settled relative to the piles, negative skin friction developed with a magnitude equal to about 50% of the positive skin friction measured in a static pile load test. Following the second blast, where significant load was applied to the piles, liquefaction developed throughout a 6-m thick layer. During reconsolidation, the liquefied sand settled a maximum of 80 mm (1.1% volumetric strain) while pile settlements ranged from 71 to 104 mm (2.8 to 4.1 in). The reduced side friction in the liquefied sand led to full mobilization of side friction and end-bearing resistance for all test piles below the liquefied layer and significant pile settlement. Because the piles generally settled relative to the surrounding ground, positive skin friction developed as the liquefied sand reconsolidated. Once again, skin friction during reconsolidation of the liquefied sand was equal to about 50% of the positive skin friction obtained from a static load test before liquefaction.

Deep foundations such as driven piles are often used to bypass liquefiable layers of soil and bear on more competent strata. When liquefaction occurs, the skin friction around the deep foundation goes to zero in the liquefiable layer. As the pore pressures dissipate, the soil settles. As the soil settles, negative skin friction develops owing to the downward movement of the soil surrounding the pile. To investigate the magnitude of the skin friction along the shaft three driven piles, an H-pile, a closed end pipe pile, and a concrete square pile, were instrumented and used to measure soil induced load at a site near Turrell, Arkansas following blast-induced liquefaction. Measurements were made of the load in the pile, the settlement of the ground and the settlement of piles in each case. Estimates of side friction and end-bearing resistance were obtained from Pile Driving Analyzer (PDA) measurements during driving and embedded O-cell type testing. The H-pile was driven to a depth of 94 feet, the pipe pile 74 feet, and the concrete square pile 72 feet below the ground surface to investigate the influence of pile depth in response to liquefaction. All three piles penetrated the liquefied layer and tipped out in denser sand. The soil surrounding the piles settled 2.5 inches for the H-pile, 2.8 inches for the pipe pile and 3.3 inches for the concrete square pile. The piles themselves settled 0.28 inches for the H-pile, 0.32 inches for the pipe pile, and 0.28 inches for the concrete square pile. During reconsolidation, the skin friction of the liquefied layer was 43% for the H-pile, 41% for the pipe pile, and 49% for the concrete square pile. Due to the magnitude of load felt in the piles from these tests the assumption of 50% skin friction developing in the liquefied zone is reasonable. Reduced side friction in the liquefied zone led to full mobilization of skin friction in the non-liquefied soil, and partial mobilization of end bearing capacity. The neutral plane, defined as the depth where the settlement of the soil equals the settlement of the pile, was outside of the liquefied zone in each scenario. The neutral plane method that uses mobilized end bearing measured during blasting to calculate settlement of the pile post liquefaction proved to be accurate for these three piles.

Under Mediterranean environments water and nitrogen (N) are considered the two factors most strongly limiting crop productivity. Wheat (bread and durum) and barley are the main crops grown in dryland Mediterranean environments. Within the Mediterranean basin, wheat is usually cultivated in rotations with other crops under relatively humid zones while barley is sown as a monoculture in the driest zones. Reasons behind barley monoculture are based on an hypothetical barley yield advantage over wheat under stressed environments. However, information about direct comparison between wheat (bread or durum) and barley is not abundant for the Mediterranean basin (nor for other Mediterranean regions). Neither grain yield nor biomass production, water use, nitrogen use or their use efficiency have been compared for the three species to justify the preference of one of them in monoculture in the more scarce resource availability environments.
The main objective of the present thesis was to assess the response of wheat (bread and durum) and barley in terms of productivity to different water and nitrogen availabilities within the Mediterranean conditions of dryland cereal regions of Catalonia. Within the main objective two specific objectives were formulated (i) to provide empirical support to the generalized hypothesis of a better performance of barley than wheat under stress conditions, and (ii) to analyze if N fertilization could be a management tool to increase grain yield under stressful Mediterranean conditions for small grain cereals (in cases in which soil N were low). To fulfil the objectives data taken from a literature revision, and historical and regional data were analysed combined with those from five field experiments that were carried-out using different combinations of water and N availabilities for a typical well-adapted and representative cultivar of bread wheat, durum wheat and barley during 2003/04 to 2006/07 growing seasons in a typical dryland region of Catalonia where barley represent c. 80 % of the total cereal acreage.
Across all the experimental conditions grain yield of the three species varied widely from c. 1 to 10 Mg ha-1. Under the driest and poorest yielding conditions barley presented similar yields to wheat (bread and durum) using the experimental data, but also using the bibliographic, historical and regional data, indicating an unjustified barley monoculture in terms of productivity. Despite similar yield between durum wheat and barley a lower stability in grain weight was observed for the case of durum wheat. Neither water use or N use or their use efficiencies supported the hypothesised advantage of barley over wheat across the driest experimental conditions. Water availability and N fertilization modified grain yield, biomass and resource use efficiency. In the present thesis, it was evidenced with realistic field data for the first time that of the degree of co-limitation between factors (N and water in this case) may affect yields as well as water use efficiency of small grain cereals, which had been previously proposed but using simulation models for wheat production in Australia.

CIVINS
The recent trend of using fine water mist systems to replace the legacy HALON-1301 fire suppression systems warrants further study into other applications of the water mist systems. Preliminary research and investigation indicates that fine mists (20-25 micro droplet size) may reduce peak overpressures of a shock wave traveling through a space. Such pressure reductions could be used to mitigate the destructive effects of a shock wave (initiated by an explosive device) traveling through a structure. Currently these blast mitigation effects have only been demonstrated in small-scale shock tube tests and computer simulations. Uncertainty exists as to the scalability of such a system. The intention of this research is to investigate the applicability of such a blast mitigation system for shipboard use. Study into the degree of mitigation necessary to make a system practical for shipboard installation was conducted. In addition, a theoretical study of the mechanisms of blast mitigation using water mists was completed.
CIVINS

Un dels principals mètodes per incrementar els rendiments del cultius és l'aplicació de fertilitzants, principalment el nitrogen (N). Aplicacions insuficients de N poden provocar importants pèrdues econòmiques per als agricultors, mentre que aplicacions excessives incrementen el risc de contaminació ambiental. La present tesi doctoral pretén contribuir al desenvolupament de sistemes agrícoles més sostenibles mitjançant la millora de l'eficiència del N. Protocols sobre el mostreig de sòls, imatges aèries multiespectrals i estratègies de doble cultiu han estat analitzades per millorar les pràctiques de fertilització nitrogenada. Densitats òptimes de mostreig de sòl de 3.75 i 12.5 mostres/ha es van determinar per a la matèria orgànica (MO) i pel contingut de nitrats, respectivament. En una altre capìtol de la tesis, els índexs de vegetació basats en el verd van ser més precisos que els basats en el vermell per predir el rendiment de gra del blat de moro i la dosi òptima de fertilització en V12. El sistema de doble cultiu anual (ordi-blat de moro) va tenir produccions de 20 Mg de gra/ha i 35 Mg de biomassa/ha, amb aplicacions anuals de 230-240 kg de N/ha dividides entre els dos cultius, mostrant l'alt potencial de rendiment i la seva estabilitat comparativament amb estratègies de monocultiu.
Uno de los principales método para incrementar los rendimientos es la aplicación de fertilizantes, principalmente el nitrógeno (N). Aplicaciones insuficientes de N pueden provocar graves pérdidas económicas para los agricultores, mientras que aplicaciones excesivas incrementan el riesgo de contaminación ambiental. La presente tesis doctoral pretende contribuir al desarrollo de sistemas agricolas más sostenibles mediante la mejora de la eficiencia del N. Protocolos de muestreo de suelos, imágenes aéreas multiespectrales y estratégias de doble cultivo anuales han sido analizadas para mejorar las prácticas de fertilización nitrogenada. Densidades óptimas de muestreo de 3.75 y 12.5 muestras/ha se determinaron para materia orgánica (OM) y nitratos, respectivamente. En otro capítulo de la tesis, los indices de vegetación basados en el verde fueron más precisos que los basados en el rojo para predecir el rendimiento de grano del maíz y la dosis óptima de fertilización en V12. El sistema de doble cultivo anual (cebada-maíz) obtuvo producciones de 20 Mg de grano/ha y 35 Mg de biomasa/ha, con aplicaciones anuales de 230-240 kg N/ha divididas entre los dos cultivos, mostrando el alto potencial de rendimiento y su estabilidad cuando se compara con estrategias de monocultivo.
One of the main methods for increasing yields is the application of mineral fertilizers, mainly nitrogen (N). Insufficient application of N can have serious economic consequences for the farmer, whereas excessive fertilization increases the risk of environmental pollution. Traditionally, N fertilization of field crops, such as maize, has been adjusted by yield-based N recommendations methods.The present Ph.D. Thesis aims to contribute to the development of more sustainable agricultural systems by improving nitrogen efficiency. Soil sampling protocols, multispectral aerial images and double-annual cropping strategies and methods were analysed to improve the N fertilization practices. Optimum soil sampling densities of 3.75 and 12.5 samples/ha were determined for organic matter (OM) and nitrates, respectively. In other chapter of the Thesis, Green-based vegetation indices (VIs) were more accurate than red-based ones in predicting grain yield and in determining the optimum N rate for maize at V12 stage. Doble-annual cropping systems (barley-maize) yield up to 20 Mg of grain/ha and 35 Mg of biomass/ha, with annual N rates of 230-240 kg N/ha split between both crops, showing high yielding potential and yield stability when compared with mono-cropping strategies.

Flyrock remains a significant risk to the health and safety of the mine’s employees and infrastructure as well as the safety of the neighbouring communities and their property. Losses and damages can result in significant financial and reputation consequences. The lack of fundamental research in recent years and quantifiable data relating to the relationship between blast design parameters and the risk of flyrock motivated this project. A number of authors concluded that major gaps in knowledge relative to flyrock caused by its random nature still remain a weakness in the field. Recent papers published (since 2010) proposed a wide range of potential approaches and techniques to predict or investigate flyrock. However, the majority of these papers concluded that the proposed results were site-specific and could not be applied to other environments. The focus of this project was to develop a concept that is able to quantify the flight path of the flyrock resulting from a blast. The motivation behind the development of this concept was to enable future researchers to quantify the impact of the different blast design parameters on the measured flyrock. Various technologies were considered and investigated during this project. After a comparative analysis of these technologies, it was decided to use photogrammetry as the foundation of the proposed concept tool. The proposed concept consists of three main phases, namely (1) data acquisition, (2) image processing and data analysis and (3) data interpretation. To date, progress has been achieved with phase one and phase two. In phase one, all objectives have been met. However, there are still areas which need refinement, specifically regarding the placement of the cameras in the field. In phase two, success was achieved with the proof of concept exercise in a controlled environment using a clay pigeon as the projectile. The process of calibrating the lenses has been established, however, further optimization is possible. Point-cloud data was successfully generated in the concept test, but converting the image data from subsequent quarry test blasts proved more challenging and is still a work in progress. Once phase two has been satisfactorily resolved, attention will focus on phase three. Results to date have given a positive indication that the concept is viable and that additional work will prove the technology functional. Ultimately, it is envisioned that this tool can be used for one of three purposes, namely: • Mines can generate a database with accurate historical flyrock of their blasting operations. • Research teams can implement this tool to conduct quantitative research and investigations into flyrock and the impact of different blast design parameters on the risk of flyrock. • Point-cloud data combined with ballistics calculations can be used to visualise blasts and flyrock in Virtual Reality for training and education.
Dissertation (MEng)--University of Pretoria, 2019.
AEL Mining Services Chair in Innovative Rock Breaking
Mining Engineering
MEng
Unrestricted

És molt freqüent que el panís rebi dosis de N de font orgànica o mineral molt superiors a les que el conreu pot extreure, pràctica que pot agreujar la problemàtica de la contaminació dels aqüífers amb nitrats, afectar la rendibilitat econòmica del conreu i també causar contaminació del sòl per acumulació de metalls pesants. La dosi de 200 kg N mineral ha-1 va esser la que a llarg termini va permetre obtenir màxims rendiments de gra (~14 Mg ha-1), una eficiència de l'ús del N major del 80%, i uns continguts de N residual moderats. Aquesta dosi al seu torn coincideix amb el màxim permès a la zona d'estudi, una zona designada com a vulnerable a la contaminació per nitrats segons la legislació vigent. Després de dotze anys d'aplicacions continuades de purins de porc, a una dosi de 50 m3 ha-1 any-1 , es va detectar un increment del contingut de Cu i Zn del sòl, encara que les concentracions van estar molt per sota de les considerades fitotòxiques o les no autoritzades per la legislació vigent. Tant la fertilització amb N mineral, purí de porc i fem de vaquí de llet acompanyada d'una incorporació al sòl dels residus de collita, va resultar en increments dels nivells de carbó orgànic del sòl en els primers 30 cm, indicant que contribueixen al manteniment o millora de la qualitat del sòl.
Es muy frecuente que el maíz reciba dosis de N de fuente orgánica o mineral muy superiores a las que el cultivo pueda extraer, práctica que puede agravar la problemática de la contaminación de los acuíferos con nitratos, afectar a la rentabilidad económica del cultivo y también causar contaminación del suelo por acumulación de metales pesados. La dosis de 200 kg N mineral ha-1, fue la que a largo plazo permitió máximos rendimientos de grano (~14 Mg ha-1), una eficiencia del uso del N mayor del 80%, y unos contenidos de N residual moderados. Esta dosis a su vez coincide con las aplicaciones máximas de N permitidas en la zona de estudio, una zona designada como vulnerable a la contaminación por nitratos según la legislación vigente. Después de doce años de aplicaciones continuadas de purín de cerdo, a una dosis de 50 m3 ha-1 yr-1, se detectó un incremento del contenido de Cu y Zn del suelo, aunque las concentraciones estuvieron muy por debajo de las consideradas fitotóxicas o las no autorizadas por la legislación vigente. Tanto la fertilización con N mineral, purín de cerdo y estiércol de vacuno de leche, acompañada de una incorporación al suelo de los residuos de cosecha, resultó en incrementos de los niveles de carbón orgánico del suelo en los primeros 30 cm, indicando que contribuyen al mantenimiento o mejora de la calidad del suelo.
It is very common in maize cultivation to apply N rates from organic or mineral source much higher than the crop uptake, a practice that can aggravate the problem of contamination of aquifers with nitrates, affect the economic profitability of the crop and also cause contamination of the soil by accumulation of heavy metals. The rate of 200 kg N ha-1 which allowed maximum grain yields (~14 Mg ha-1), presented an N use efficiency greater than 80%, and also moderate residual N content. This N rate, in turn, coincides with the maximum allowed in the study area, an area designated as vulnerable to nitrate pollution according to current legislation. After twelve years of continuous applications of pig slurry, at rate of 50 m3 ha-1 yr-1, an increase in soil Cu and Zn content was detected, although the concentrations were well below levels considered phytotoxic or not permitted by current legislation. Fertilization with mineral N, pig slurry and cattle manure, accompanied by soil incorporation of crop residues, resulted in increases in soil organic carbon levels in the first 30 cm soil layer, indicating that they contribute to the maintenance or improvement of soil quality.

L’objectiu de la present Tesi Doctoral ha estat contribuir al coneixement existent sobre la formació del rendiment en blat i la qualitat del gra, així com l’efecte que les variables ambientals exerceixen sobre ambdós. Per això, es va analitzar una sèrie històrica formada per 24 genotips de blat dur, representatius dels cultivats a España i Itàlia al llarg del segle passat, i una col•lecció de 20 varietats de blat fariner escollides entre les més cultivades a España durant les últimes dècades i representatives dels 4 grups de qualitat industrial. Es va estudiar l’efecte de l’al•lel enanitzant Rht-B1b sobre la biomassa aèria i radicular i les seves conseqüències sobre la formació del rendiment, els canvis causats per la millora genètica en la qualitat del gra i els patrons d’adaptació (interacció Genotip x Ambient), així com l’efecte de les variables meteorològiques sobre el rendiment, els seus components i la qualitat.
El objetivo de la presente Tesis Doctoral fue contribuir al conocimiento existente sobre la formación del rendimiento en trigo y la calidad del grano, así como del efecto que las variables ambientales ejercen sobre ambos. Para ello se utilizó una serie histórica formada por 24 genotipos de trigo duro, representativos de los cultivados en España e Italia a lo largo del pasado siglo, y una colección de 20 variedades trigo harinero escogidas entre las más cultivadas en España en las últimas décadas y representativas de los 4 grupos de calidad industrial. Se estudió el efecto del alelo enanizante Rht-B1b sobre la biomasa aérea y radicular y sus consecuencias sobre la formación del rendimiento, los cambios causados por la mejora genética en la calidad del grano y los patrones de adaptación (interacción Genotipo x Ambiente), así como el efecto de las variables meteorológicas sobre el rendimiento, sus componentes y la calidad.
The objective of this Doctoral Thesis was to contribute to the existing knowledge of yield and grain quality formation, as well as the effect that the meteorological variables exert on them. For this, an historical series of 24 durum wheat genotypes was used, being all of them representative of those used in Spain and Italy during the last century. Moreover, a set of 20 bread wheat varieties was selected among the most cultivated in Spain during the last decades, which were representative of the four industrial quality groups. The effect of the Rht-B1b dwarfing allele on aerial and root biomass and its consequences on yield formation was assessed. Plant breeding effects on grain quality and adaptation patterns (Genotype x Environment interaction) and the effect of meteorological variables on yield, yield components and quality was also studied.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering; and, (S.M. in Real Estate Development)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, Center for Real Estate, 2006.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (leaves 267-268).
This thesis is divided into two distinct parts. Part 1 relates to the requirements of the S.M.C.E.E. degree, and Part 2 relates to the M.S.R.E.D. degree. Part 1: The Influence of Boundary Conditions and Higher Mode Shapes on First-Crack Prediction for Blast-Resistant Glazing Systems: This study reviews the extent to which two commonly used assumptions in the design of blast-resistant glazing systems influence modeling results. Blast-resistant glazing designers typically model glazing by assuming that glass plates are simply supported on four edges, and that they can be represented by a single degree of freedom model that assumes one mode of vibration. In reality, glazing sealants provide elastic support, and the dynamic response of plates to blast loads consists of the superposition of several modes of vibration. This study investigates the inaccuracy caused by these assumptions by comparing conventional results to those of more sophisticated finite element analyses.
(cont.) Part 2: A Survey of Incentive Programs and Strategies for Large-Scale, "Smart Growth" Developments in Massachusetts: Chapter 40R/40S, TIFIDIF/UCH-TIF, Special Development Districts, Affordable Housing Programs & Grant Programs: Politicians and legislators have placed a significant amount of emphasis on high-density, transit-oriented development as a method of dealing with the "housing crisis" in Massachusetts. However, the type of infill redevelopment projects that the state wishes to encourage often face feasibility problems related to high infrastructure costs associated with redevelopment, rising construction costs, high affordability requirements, and/or the cost of creating structured parking. This study examines the extent to which several newly created and existing programs are capable of helping large-scale smart growth projects attain feasibility and it provides strategies for using them. The surveyed programs include Chapter 40R/40S, TIF/DIF/UCH-TIF and special development districts, Affordable Housing Programs and other Grants.
by Abraham Menzin.
S.M.in Real Estate Development
S.M.

The aim of this study was to assess the environmental effects of Moshyttan, one of the earliest known blast furnaces in Europe (ca. 11th century). The study was based on the analysis of three lake records in the immediate surroundings of the smelter. Fickeln lies directly downstream and is the main recipient of waterborne pollution. Mosjökälla lies directly upstream and served as the main water reservoir for the water-powered bellows. Kramptjärnen lies 1 km to the NW in a separate catchment and acts as a reference. The data includes 31 elements analyzed by X-ray fluorescence spectroscopy (XRF), organic content inferred from loss on ignition (LOI), biogenic silica (BSi) modeled from Fourier-transform infrared spectroscopy (FT-IRS) for all lakes and diatom counts for Fickeln. Two other studies provided dating of slag from the smelter and pollen- and geochemical data from Fickeln. The results show that the metallurgy and associated activities (e.g. agriculture, forest grazing and charcoal production) led to eutrophication and alkalization in Fickeln. This is indicated by the diatom community that in the background is dominated by benthic genera indicative of oligotrophy and dystrophy (Frustilia, Brachisyra and Eunotia) that during the active smelter phase is replaced by pelagic genera indicative of eutrophy (Aulacoseira and Asterionella). BSi also decreases after smelter establishment, which speculatively could indicate an overall decrease in diatom production. At the same time, a suite of elements commonly associated with iron processing (Fe, Pb and Zn) increase in the sediment.

El blat és un cultiu que aporta el 20% de les proteïnes i les calories per al consum humà a nivell global. L’adaptació de la data de floració a cada ambient en particular forma part d’un mecanisme d’escapament de l’estrès, cosa que podria reduir l’impacte negatiu esperat degut al canvi climàtic. La hipòtesi general sobre la que s’estableix aquest estudi és que un canvi en la data de floració afectaria les condiciones ambientals durant les fases crítiques de desenvolupament del blat, que al seu torn poden tenir un impacte en la formació del rendiment. Un conjunt de línies de blat dur de primavera, amb variacions al·lèliques contrastants per als loci Ppd-1, que afecten la sensibilitat al fotoperíode, es van assajar en un ampli rang de latituds de l’hemisferi Nord (41°N a Espanya, 27°N al noroest de Mèxic, i 19°N al sud de Mèxic, aquesta darrera amb sembra de primavera). Es van portar a terme experiments de camp en regadiu, entre els anys 2007 i 2012, per a investigar l’efecte de les variants al·lèliques en els loci Ppd-A1 i Ppd-B1 sobre la fenologia i la formació del rendiment. Els genotips portadors de l’al·lel Ppd-A1a GS100, causant d’insensibilitat al fotoperíode, van tendir a presentar un pes de gra (PG) i un rendiment superiors a la resta. Les variants al·lèliques per a Ppd-B1 no van afectar la data de floració, però l’al·lel causant d’insensibilitat al fotoperíode (Ppd-B1b) es va associar a un major número de grans per unitat de superfície (NG), degut a un augment en el número d’espiguetes espiga-1. Una floració més precoç (tant si era degut a Ppd-1 com a precocitat intrínseca, Eps), va tendir a una associació amb un rendiment més alt degut a un major PG. Les combinacions al·lèliques GS105/Ppd-B1b i Ppd-A1b/Ppd-B1b es van associar amb un increment del NG degut a un augment del número de grans espigueta-1, però això no es va traduir en un rendiment major, degut a la relació negativa entre NG i PG. Una floració més precoç produïda per gens Eps va resultar en un menor número d’espiguetes espiga-1, però no un menor NG. Quan ambdós al·lels en els loci Ppd-1 presentaven el mateix tipus de resposta al fotoperíode (sensible/sensible o insensible/insensible) es va observar una major estabilitat en el rendiment. Les condicions ambientals durant la primera meitat del període d’ompliment del gra van ser els factors més importants per definir el PG. Un retràs en la data de floració es va associar amb reduccions en la taxa d’ompliment de gra i amb PG. En les latituds amb sembra de tardor, un increment de 1°C en la temperatura mitjana va reduir el PG en 5,2 mg gra-1. L’anàlisi d’associació genotip-fenotip va mostrar que les regions als cromosomes 6A (114 cM) i 6B (126 cM) tenien associacions generals amb el rendiment, esdevenint regions crítiques amb QTLs importants. La detecció de marcadors únics associats a una característica va estar molt lligada a l’ambient, i la interacció entre parells de marcadors va mostrar major efecte que els corresponents marcadors únics.
El trigo es un cultivo que aporta el 20% de las proteínas y calorías para el consumo humano a nivel global. La adaptación de la fecha de floración a cada ambiente en particular forma parte de un mecanismo de escape al estrés, lo que podría reducir el impacto negativo esperado debido al cambio climático. La hipótesis general sobre la que se establece este estudio es que un cambio en la fecha de floración afectaría a las condiciones ambientales durante las fases críticas del desarrollo del trigo, lo que a su vez puede tener un impacto en la formación del rendimiento. Un conjunto de líneas de trigo duro de primavera, con variaciones alélicas contrastantes para loci Ppd-1, que afectan la sensibilidad al fotoperiodo, fueron ensayadas en un amplio rango de latitudes del hemisferio Norte (41°N en España, 27°N en el noroeste de México, y 19°N en el sur de México, esta última con siembra de primavera). Se llevaron a cabo experimentos de campo en regadío, entre los años 2007 y 2012, para investigar el efecto que tuvieron las variantes alélicas en los loci Ppd-A1 y Ppd-B1 sobre la fenología y la formación del rendimiento. Los genotipos con el alelo Ppd-A1a GS100, causante de insensibilidad al fotoperiodo, tendieron a presentar un peso de grano (PG) y un rendimiento superiores al resto. Las variantes alélicas para Ppd-B1 no afectaron a la fecha de floración, pero el alelo causante de insensibilidad al fotoperiodo (Ppd B1b) aumentó el número de granos por unidad de superficie (NG) debido a un aumento de número de espiguillas espiga-1. Una floración más temprana (ya fuera debida a Ppd-1 o a precocidad intrínseca, Eps) tendió a estar asociada con rendimiento más alto debido a un PG mayor. Las combinaciones alélicas GS105/Ppd-B1b y Ppd-A1b/Ppd-B1b se asociaron con un incremento de NG debido a un aumento del número de granos espiguilla-1, pero esto no se tradujo en un mayor rendimiento debido a la relación negativa entre NG y PG. Una floración más temprana producida por genes Eps tuvo como resultado un menor número de espiguillas espiga-1, pero no un menor NG. Cuando ambos alelos en los loci Ppd-1 poseían el mismo tipo de respuesta al fotoperiodo (sensible/sensible o insensible/insensible) se observó una mayor estabilidad en el rendimiento. Las condiciones ambientales durante la primera mitad del periodo de llenado de grano fueron los factores más importantes para definir el PG. Un retraso en la fecha de floración se asoció con reducciones en la tasa de llenado de grano y el PG. En las latitudes donde la siembra se realizó en otoño, un incremento de 1°C en la temperatura media redujo el PG en 5,2 mg grano-1. El análisis de asociación de fenotipo-genotipo mostró que las regiones en los cromosomas 6A (114 cM) y 6B (126 cM) se asociaron en general con el rendimiento, representando regiones críticas con QTLs importantes. La detección de marcadores únicos asociados a una característica estuvo muy ligada al ambiente, y la interacción entre pares de marcadores mostró mayor efecto que sus correspondientes marcadores únicos.
Wheat is a staple crop that provides 20% of proteins and calories to global human diets. Adapting flowering time to each particular environment is one of the stress avoidance mechanisms that could reduce the predicted impact of climate change. The general hypothesis underlying this research was that a change in flowering time would affect environmental conditions of spring durum wheat during critical developmental phases, which in turn would have an impact on yield formation. A set of spring durum wheat lines with contrasting allele variants at Ppd-1 loci, affecting photoperiod sensitivity, were tested at a range of Northern latitudes (41°N in Spain, 27°N in the northwest of Mexico, and 19°N in the south of Mexico, this last site with spring sowing time). Field experiments under irrigation were carried out between the years 2007 and 2012, to investigate the effect of allele variants at Ppd-A1 and Ppd-B1 loci on phenology and yield formation. Genotypes carrying the allele Ppd-A1a GS100, causing photoperiod insensitivity, tended to have high grain weight (GW) and yield. Allele variants at Ppd-B1 locus did not affect flowering time, but the Ppd-B1b allele causing photoperiod sensitivity increased grain number per unit area (GN) due to a higher number of spikelets spike-1. Early flowering (either due to Ppd-1 or earliness per se, Eps) tended to be associated with high yield due to high GW. The allele combinations GS105/Ppd-B1b and Ppd-A1b/Ppd-B1b were associated with higher GN due to an increase in the number of grains spikelet-1, but it did not translate as yield increase due to a trade-off between GN and GW. Early flowering caused by Eps genes resulted in a low number of spikelets spike-1, but not a low GN. Yield stability was enhanced when alleles at Ppd-1 loci conferred a similar photoperiod response (sensitive/sensitive or insensitive/insensitive). The environmental conditions during the first half of the grain filling period were the most critical factors to define GW. Flowering time delays were associated with reductions in grain filling rate and GW. At autumn-sowing sites, an increase of 1°C in mean temperature reduced GW by 5.2 mg grain-1. The analysis of phenotype-genotype associations showed that the regions at chromosomes 6A (114 cM) and 6B (126 cM) were associated with yield across sites, thus representing hotspots for QTL regulating yield performance. The detection of single markers-trait associations (MTAs) was highly affected by environment, and the interactions between pairs of markers showed a stronger effect than the corresponding single MTAs.

It has been assumed that durum wheat is more productive under stress than bread wheat (geographical distribution and statements in the literature). However, this is not known as only few research papers compared the performance of both crops, and in no case under a wide range of environments in field conditions. This study did precisely this sort of comparison, along 3 experimental years in which a range of fertilization and irrigation treatments were applied. In addition, a comprehensive database with data from field experiments was gathered and meta-analysed. We found from both approaches a cross-over interaction of yield of bread and durum wheat, but rejecting the hypothesis: bread outyielded durum wheat in the low-yielding conditions while durum wheat tended to have higher yield potential as a consequence of differences in sink strength in post-anthesis. The causes under the yield interaction and its consequences in efficiency terms are discussed.
Se acepta comúnmente que los trigos duros son más productivos que los trigos harineros en ambientes de estrés (en su distribución geográfica y en la literatura). Sin embargo, dicha asunción no está plenamente demostrada dados los pocos artículos científicos que comparan el comportamiento de ambas especies en condiciones de campo, que en ningún caso presentan un amplio rango ambiental. Este estudio evaluó dicha comparación a lo largo de 3 años experimentales en los que se aplicó un amplio rango de condiciones de fertilización y riego. Adicionalmente, se realizó una exhaustiva base de datos de experimentos que fue meta-analizada. Se encontró con ambas aproximaciones una interacción de tipo cualitativa del rendimiento entre ambas especies con el ambiente, aunque rechazando la hipótesis original: el rendimiento del trigo harinero fue mayor que el del trigo duro en los ambientes con bajo rendimiento y, al contrario, el trigo duro tendió a expresar un rendimiento potencial más alto como consecuencia de diferencias en la fuerza de los destinos en pos-antesis. Las causas subyacentes en la interacción del rendimiento y sus consecuencias en términos de eficiencia han sido ampliamente tratadas.
Els blats durs han estat àmpliament acceptats com a més productius en ambients d’estrès que els blats fariners (en la seva distribució geogràfica i en la literatura). Tanmateix, l’esmentada assumpció no està plenament demostrada a causa dels pocs articles científics que comparen el comportament de ambdues espècies en condicions de camp, que en cap cas presenten un ampli rang ambiental. Aquest estudi avaluà la dita comparació durant 3 anys experimentals en els quals un ampli rang de condicions de fertilització i reg varen ser aplicats. Addicionalment, es realitzà una exhaustiva base de dades de experiments que fou meta-analitzada. Totes dues aproximacions presentaren una interacció amb l’ambient de tipus qualitatiu del rendiment entre les dues especies de blat, encara que rebutjant la hipòtesis original: el blat fariner va rendir més que el blat dur en els ambients de baix rendiment i, contràriament, el blat dur va tendir a expressar un rendiment potencial més alt a conseqüència de diferències en la força dels destins en post-antesis. Les causes que produïren la interacció del rendiment i les conseqüències en termes d’eficiència han estat àmpliament estudiades.

To foster the practical development of constructed wetlands used for wastewater treatment in Turkey, a pilot-scale subsurface constructed wetland system (90 m2) was designed to treat the domestic wastewater produced by 60 PE living in the residential area of METU. In summer 2001, two parallel sets of hybrid wetland systems (vertical flow connected with horizontal flow) with identical design configuration, but with different fill media (blast furnace granulated iron slag and gravel) were built on the old sludge-drying bed of the abandoned wastewater treatment plant of METU, which has not been operating since the 1990s. Wetland cells were planted with common reed (Phragmites australis). The main objective of this research was to quantify the effect of different filter media on the removal performance of subsurface flow constructed wetlands in the prevailing climate of Ankara. Thus, slag-filled and gravel-filled vertical flow wetlands were operated identically with pre-settled domestic wastewater (3 m3.d-1) at a hydraulic loading rate of 110 mm.d-1 for 12 months, intermittently. According to the first year results, annual average removal efficiencies for the slag and gravel wetland cells were as follows: TSS (63% &
59%), COD (47% &
44%), NH4+-N (88% &
53%), TN (44% &
39%), PO43--P (44% &
1%) and TP (45% &
4%). The slag-filled vertical flow system removed phosphorus and ammonium efficiently than the gravel-filled system due to the differences in physical structures and chemical compositions of the fill media, and the different aerobic and anaerobic environments within the wetland cells. These results indicated that the well-designed constructed wetlands could also be used for secondary and tertiary treatment in Turkey, successfully.

A method of producing steel that is not used in Sweden today is direct reduction using natural gas, a method which could has enormous potential in the future of steelmaking. Historically, steelmaking prioritized productivity and profitability. However, other aspects such as safety, sustainability, and environmentally friendliness have become increasingly important to Swedish steelmakers. This study evaluates the usage of natural gas to  directly reduce iron ore into the porous form known as iron sponge, then finally processing that sponge into crude steel. The technology available today is assessed through a literature review, then two calculative data-based model: using DRI sponge in a traditional integrated steelmaking line or replacing steel scrap with it in an electric arc furnace. While this technology is used in many regions where natural gas is plentiful, it has not yet been used in Sweden. Now, when the Swedish natural gas network is expanding and the vehicular transportation of liquid natural gas is becoming more and more viable, it is a prime situation to evaluate direct reduction in Sweden. While models require assumptions and estimations, they suggest that DRI will absolutely be a viable option in the years to come. Integrated plant operators can reduce their immense carbon emissions for a reasonable price, while DRI sponge melting in an electrical arc furnace can either help steelmakers escape the volatile scrap market or be used to replace the blast furnace as a whole in the future.
En metod för att producera stål som inte används i Sverige idag är direkt reduktion med hjälp av naturgas, en metod som har en enorm potential i framtida ståltillverkning. Historiskt har ståltillverkningen prioriterat produktivitet och vinst, men säkerhet, hållbarhet, och miljövänlighet har blivit områden mer och mer viktiga för svenska ståltillverkare. Den här studien utvärderar användningen av naturgas för att direkt reducera järnmalm till den porösa formen känd som järnsvamp, och sen bearbeta den till primärt stål. Teknologin som flnns idag utvärderas genom en litteraturstudie, vars data beräknas till två scenariomodeller: användningen av järnsvamp i ett traditionellt integrerat stålverk eller genom att ersätta stålskrot med järnsvamp i ljusbågsungen. Den här teknologin används redan idag i regioner där naturgas är lättillgängligt, men har hittills inte använts i Sverige. Men nu när Sveriges naturgasnät byggs ut och fordonstransporterad flytande naturgas blir mer och mer kostnadseffektiv så är det lämpligt att utvärdera direkt reduktion i Sverige. Modellerna kräver antaganden och uppskattningar, men de pekar på att direkt reducering av järnmalm kommer att vara en genomförbar metod för ståltillverkning i en nära framtid. Integrerade masugnslinjer kan minska sina enorma koldioxidutsläpp till ett rimligt pris, och järnsvampssmältning i ljusbågsugn kan hjälpa ståltillverkare att undanfly den instabila stålskrotsmarknaden eller användas för att helt ersätta masugnsproduktion i framtiden.

[EN] Rice (Oryza sativa L) is the main staple food for over 3 billion people (almost half the world population), and rice blast, caused by the fungus Magnaporthe oryzae, is the major threat for this crop worldwide, triggering also important losses in Spain some years. Some resistant cultivars have been released, mainly with complete resistance genes (Pi genes), but their resistance has not lasted long, due to the emergence of new virulent isolates. Therefore, the efforts for obtaining effective and durable resistance are focused nowadays on the use of partial resistance or a combination of partial and complete resistance. Partial resistance is a quantitative character, controlled by numerous genes of small effects (QTLs), that can interact among them, and usually also strongly with the environment. For a better knowledge of the population of M. oryzae in the Albufera region, and of the resistance genes and QTLs that might be effective in various Spanish rice growing regions, we tested along four years 31 differential varieties (isogenic lines carrying one different Pi gene each); these studies showed that fungus population can significantly change from one year to the other. On the other hand, we analyzed the genetics of resistance to M. oryzae in two populations derived from crosses between local and well adapted, although moderately susceptible, varieties (Sivert, JSendra), and allegedly resistant but poorly adapted varieties (CAN-6159, Gigante Vercelly. In F3 lines of both populations, the leaf and panicle susceptibility was determined in field trials under conditions that favour the infection: SixCNA lines were tested in a plot in the Albufera region, and those of JSxGV in four locations of Valencia, the Ebro River Delta, and Seville; inoculations in controlled conditions were also carried out in the second population. We compare the different methodologies for assessing susceptibility, and we discuss the environmental influence on it. 22 QTLs were detected in SIxCNA, and 61 in JSxGV, most of them in only one location. All four parents displayed partial resistance QTLs; but some QTLs showed small additive effects and, often, high dominance. At the same time, most of these QTLs exhibit significant interactions with other QTLs; and many of them co-localize with QTLs found in other studies. We have discovered substantial coincidences between QTLs that control incidence in panicle and those that determine leaf severity, thus supporting the hypothesis that there are common defence mechanisms in both organs. Chromosomal regions of interest for marker assisted breeding of resistant genotypes have been identified.
[ES] El arroz (Oryza sativa L.) es la principal fuente de alimentación para más de 3.000 millones de personas, casi la mitad de la población mundial, y la "piriculariosis", causada por el hongo Magnaporthe oryzae Couch, es la enfermedad que más pérdidas causa en este cultivo a escala mundial; también en España ha causado pérdidas importantes algunos años. Se han obtenido diversas variedades resistentes, principalmente al incorporar genes de resistencia completa (genes Pi), pero la mayoría se han vuelto susceptibles en pocos años al aparecer nuevos aislados más virulentos. Actualmente, para conseguir una resistencia efectiva y duradera, se busca incorporar resistencia parcial, o una combinación de ambos tipos de resistencia. La resistencia parcial es un carácter cuantitativo, controlado por numerosos genes de efecto pequeño (o QTLs), que pueden interaccionar entre ellos y que, con frecuencia, también lo hacen intensamente con el ambiente. Para conocer mejor la población del patógeno presente en la zona de la Albufera, y qué genes y QTLs de resistencia pueden ser efectivos en ésta y otras zonas arroceras de España, por un lado se ensayaron durante varios años 31 variedades diferenciales (líneas con un gen Pi diferente cada una); esto demostró que la estructura de la población del hongo puede variar significativamente con los años. Por otro lado, realizamos estudios genéticos sobre la resistencia a M. oryzae en dos poblaciones, procedentes del cruzamiento entre variedades locales, bien adaptadas pero moderadamente susceptibles (Sivert y JSendra) y variedades resistentes, pero no adaptadas (CNA-6159 y Gigante Vercelli). En líneas F3 de ambas poblaciones se determinó la resistencia en campo, en condiciones favorables para el ataque del hongo, en hojas y órganos productivos: en SixCNA, en una parcela de la Albufera, y en JSxGV, en 4 localidades de Valencia, el Delta del Ebro y Sevilla; en JSxGV, además, se realizaron inoculaciones en condiciones controladas. Se comparan los diferentes sistemas de medida de la susceptibilidad, y se discute la influencia ambiental en ella. Se detectaron 22 QTLs en SixCNA, y 61 QTLs en JSxGV, la mayoría de los cuales sólo se expresan en una localidad. Todos los parentales aportan alelos de resistencia; pero la mayoría de los QTLs identificados son de efectos pequeños y, a menudo, con un notable componente dominante. Al mismo tiempo, gran parte de estos QTLs presentan interacciones significativas con otros QTLs; y muchos de ellos co-localizan con QTLs identificados en otros estudios. Hemos encontrado bastantes coincidencias entre QTLs que controlan la incidencia en panículas y los que determinan la severidad en las hojas, apoyando la hipótesis de que existen mecanismos de defensa comunes en ambos órganos. Se han localizado regiones cromosómicas de interés que podrían ser utilizadas para la selección de genotipos resistentes.
[CAT] L'arròs (Oryza sativa L.) és la principal font d'alimentació per a més de 3.000 millions de persones, quasi la meitat de la població mundial, i la "piriculariosi", causada pel fong Magnaporthe oryzae Couch, és la malaltia que més pèrdues origina en aquest conreu a escala mundial; també a Espanya ha causat pèrdues importants alguns anys. S'han obtès diverses varietats resistents, principalment en incorporar gens de resistència completa (gens Pi), però la majoria s'han tornat susceptibles en pocs anys en aparèixer nous aïllats més virulents. Actualment, per aconseguir una resistència efectiva i duradora, es cerca incorporar resistència parcial, o una combinació de tots dos tipus de resistència. La resistència parcial és un caràcter quantitatiu, controlat per nombrosos gens d'efecte reduït (o QTLs), els quals poden interaccionar entre sí i que, sovint, també ho fan intensament amb l'ambient. Per conéixer millor la població del patògen present a la zona de l'Albufera, i quins gens i QTLs de resistència poden ser efectius a aquesta i a d'altres zones arrosseres d'Espanya, per una banda s'assajaren durant diversos anys 31 varietats diferencials (línies amb un gen Pi diferent cadascuna); això demostrà que l'estructura de la població del fong pot variejar significativament amb els anys. Per altra banda, realitzàrem estudis genètics sobre la resistència a M. oryzae en dues poblacions, procedents del encreuament entre varietats locals, adaptades però moderadament susceptibles (Sivert i JSendra) i varietats resistents però no adaptades (CNA-6159 i Gigante Vercelli). En línies F3 d'ambdues poblacions es determinà la resistència en camp, en condicions favorables per a l'atac del fong, en fulles i òrgans productius: en SixCNA, en una parcel·la de l'Albufera, i en JSxGV en quatre localitats de València, el Delta de l'Ebre i Sevilla; en JSxGV, a més a més, es realitzaren inoculacions en condicions controlades. Es comparen els diversos sistemes de mesura de la susceptibilidad, i es discuteix la influència ambiental en aquesta. Es detectaren 22 QTLs en SixCNA i 61 QTLs en JSxGV, la major part dels quals solament s'expressen a una localitat. Tots els parentals aporten al·lels de resistència; però alguns dels QTLs identificats són d'efectes reduïts i, freqüentment, amb un notable component dominant. Paral·lelament, gran part d'aquestos QTLs presenten interaccions significatives amb altres QTLs; i molts d'aquestos co-localitzen amb QTLs identificats en altres estudis. Hem trobat bastants coincidències entre QTLs que controlen la incidència en panícules i els que determinen la severitat a les fulles, recolzant la hipòtesi que existeixen mecanismes de defensa comuns en ambdós òrgans. S'han localitzat regions cromosòmiques d'interès que podrien ser emprades per a la selecció de genotipus resistents
Pérez Lotz, J. (2016). Análisis genético de la resistencia parcial a Magnaporthe oryzae en arroz (Oryza sativa) en varias poblaciones y ambientes [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/62582
TESIS

The development of new cultivars better adapted to specific growing conditions is a key strategy to meet an ever-increasing growing global food demand and search for more sustainable cropping systems. This is even more crucial in the context of a changing climate. Ecophysiological models and advanced computational techniques (e.g., sensitivity analysis, SA) represent powerful tools to analyze genotype (G) by environment (E) interactions, thus supporting breeders in identifying key traits for specific agro-environmental contexts. However, limits for the effective use of mathematical models within breeding programs are represented by the uncertainty in the distribution of plant trait values, the lack of processes dealing with resistance/tolerance traits in most ideotyping studies, the partial suitability of current crop models for ideotyping purposes, and the absence of modelling tools directly usable by breeders. The aim of this research was to address these issues improving methodologies already in use, proposing new paradigms for the development of crop models explicitly targeting ideotyping applications and developing tools that would encourage a deep interaction of the modelling and breeding communities. The focus was on rice, for its role as staple food for more than a half of world’s population, and on resistance/tolerance traits to biotic/abiotic stressors, for their central role in increasing crop adaptation. Moreover, current conditions and climate change projections were considered, to support the definition of strategies for breeding in the medium-long term. A standard procedure to quantify − and manage − the impact of the uncertainty in the distribution of plant trait values was developed, using the WARM rice model and the Sobol’ method as case study. The approach is based on a SA (generating sample of parameter distributions) of a SA (generating samples of parameters for each generated distribution) using distributions of jackknife statistics calculated on literature values to reproduce the uncertainty in defining parameters distributions. As a practical implication, the procedure developed allows identifying plant traits whose uncertainty in distribution can alter ideotyping results, i.e., traits whose distributions could need to be refined. Global SA was then used to identify rice traits putatively producing the largest yield benefits in five contrasting districts in the Philippines, India, China, Japan and Italy. The analysis involved phenotypic traits dealing with light interception, photosynthetic efficiency, tolerance to abiotic stressors, resistance to fungal pathogens and grain quality. Results suggested that breeding for traits involved with disease resistance and tolerance to cold- and heat-induced spikelet sterility could provide benefits similar to those obtained from improving traits affecting potential yield. Instead, advantages resulting from varying traits involved with grain quality were markedly frustrated by inter-annual weather variability. Since results highlighted strong G×E interactions, a new index to derive district-specific ideotypes was developed. Given the key role of biotic/abiotic stressors in determining actual yield and the deep impact of related G×E interactions, a study was carried out by explicitly focusing on the definition of rice ideotypes improved for their resistance to fungal pathogens and tolerance to abiotic constraints (temperature shocks inducing sterility). The analysis was carried out at district level with a high spatial resolution (5 km × 5 km elementary simulation unit), targeting the improvement of the most representative 34 varieties in six Italian rice districts. Genetic improvement was simulated via the introgression of traits from donor varieties. Results clearly showed that breeders should focus on increasing resistance to blast disease, as this appears as a factor markedly limiting rice yields in Italy, regardless of the districts and climate scenarios, whereas benefits deriving from improving tolerance to cold-induced sterility could be markedly affected by G×E interactions. To reduce the risk of discrepancies between in silico ideotypes and their in vivo realizations, both studies involved only model parameters with a close relationship with phenotypic traits breeders are working on. However, a long-term strategy to overcome limitations related with the partial suitability of available models would be building new ideotyping-specific models explicitly around traits involved in breeding programs. This proposal for a paradigm shift in model development was illustrated taking salt stress tolerance and rice as a case study. Dedicated growth chamber experiments were conducted to develop a new model explicitly accounting for tolerance traits modulating Na+ uptake and distribution in plant tissues, as well as the impact of the accumulated Na+ on photosynthesis, senescence and spikelet sterility. An ideotyping study was conducted at two sites (in Greece and California) characterized by different seasonal dynamics of salinity in field water. Results showed how, under different scenarios, traits assuring the largest contribution to the overall tolerance could refer to completely different physiological mechanisms: tissue tolerance in one case, sodium exclusion in the other. This encourages the development of explicit trait-based approaches to increase the integration of crop models within breeding programs. A parallel path to achieve this goal is the development of modelling platforms targeting breeders as final users, who does not have necessarily in-depth skills in crop modelling and IT. The platform ISIde, derived from a close collaboration between target users, biophysical modelers and IT specialists, represents the first prototype of a platform specifically developed for being used directly by breeders to evaluate in silico improved varieties at district level. This thesis demonstrated the usefulness of simulation models for the definition of ideotypes for specific agro-environmental conditions. Targeting ideotyping applications, new methodologies, paradigms for model development and modelling tools were developed, thus contributing to improve the potential of crop modelling to support breeding programs. Future developments will target researches aimed at overcoming the limits behind this study, i.e., (i) absence of explicit interactions between traits, (ii) no adaptation strategies considered, and (iii) lack of approaches for the simulation of the evolutionary potential of pathogens in response to long-term climate variations and increased host resistance.

Statistical analyses were used to develop predictive models of rice blast and to relate the favorability of environment to disease incidence and severity on different rice cultivars at five sites in Asia. The WINDOW PANE program was used to search for weather factors highly correlated with blast. Stepwise and r-square linear regression procedures were then applied to generate the predictive models at each site. Models developed at Icheon, South Korea included relative humidity and rainfall factors as the most important predictors of disease. Temperature, rainfall, wind speed, and relative humidity factors were components of models at Cavinti and the IRRI blast nursery in the Philippines. Rainfall, temperature, and solar radiation factors were important at Gunung Medan and Sitiung, Indonesia. Model validation was done to verify accuracy of models for predictions. Model predictions were also used to determine the effects on blast of sowing time, nitrogen amount, and increase in temperature. Limitations of the models are discussed. Path coefficient analysis was used to identify direct and indirect influences exerted by weather factors on blast. The largest direct influence on disease was exerted by humidity factors at Icheon; temperature, rainfall, and wind speed factors at Cavinti; temperature and humidity factors at IRRI; rainfall factors at Gunung Medan; and temperature factors at Sitiung. Although path coefficient values (Py) were estimated from the decomposition of correlation coefficients, factors that had a high correlation with disease parameters did not always give high Py. Multivariate analysis was used to determine the effects of sowing times on proneness of tropical rice to blast. Cluster analysis of 24 hypothetical sowing months at Cavinti, the IRRI blast nursery, and Sitiung sites revealed three blast proneness groups. Principal component analysis showed that IR50 cultivar would be susceptible at Cavinti at any time of the year. Sowing C22 cultivar at Cavinti in Group I and III months would make it prone to panicle and leaf blast, respectively. At the IRRI blast nursery, leaf and panicle infections on IR50 would be probable only in Group I and II months. This trend was also observed for C22 at Sitiung, although some months in Group III at this site had moderate to high degree of proneness to leaf blast.
Graduation date: 1994

博士
國立中興大學
土木工程學系所
100
Anticipating potential advantages of using HBFC（high blast furnace slag cement） concrete, in 2008 Taiwan’s Dapeng Bay Bridge is a specified structural concrete for bridge upstructures, piers and abutments for protection against chloride attack. The author endorsed a proposal to carry out a research study concerning the strength development and durability of HBFC concrete. From the practical standpoint, the implications of HBFC’s mechanical interactions with the construction site environment are unknown and not well understood. An empirical study accentuating the physical interactions of concrete in the marine environment is necessary to fully understand as well as predicting its behavior over time. The experimental variables included water-to-binder ratio, curing environment, and curing duration. The impact of these variables towards the strength, microstructure, and chloride intrusion resistance are compared to OPC concrete with the identical compressive strength to evaluate its performance nonconformities. Based on the previously conducted research, the concrete mixes for the HBFC concrete have been successfully implemented to the Pen-Bay Bridge, which was completed in February of 2011. The Pen-Bay Bridge consists of cable-stayed design with a partial drawbridge allowing unrestricted maritime access to Dapeng bay. The bridge consists of an 72.9 m high single pylon, a main span of 155 m, and a side span of 55 m. This study is incorporated with the cable-stayed bridge construction in southern Taiwan coast, is to relate the mechanical, porosity and durability properties of the high blast furnace slag cement (HBFC) concrete and the conventional ordinary Portland cement (OPC) concrete based on submerged of specimens in a sea water tank and natural exposure in the marine atmosphere zone near the construction area. Compressive strength and splitting strength at 4, 7, 28, 90, 180and 360 days, the porosity ratio at 28, 90, 180 and 360 days and the chloride penetration into concrete at 90, 180and 360 days, the microhardness at 28, 90, 180 and 360 days, the neutralization at 360 day were investigated. The high blast furnace slag cement (HBFC) used ground granulated blast furnace slag (GGBFS) as cement replacement for 45%. The variables considered include cement type, total binder content (400–475 kg/m3), water/binder (W/B) ratio (0.33,0.34,0.36) and exposure environment. The amount of GGBFS as cement replacement yielded lower compressive strengths in the early age. The results show that chlorides accumulated into concrete strongly decreases in the HBFC concrete than the OPC concrete and the inferior quality of the compressive strength in the HBFC concrete is more obviously than the OPC concrete for specimens curing in the sea water tank. The mechanical properties are affected by the cement type and curing regime. Results clearly indicated that the HBFC and a low W/B ratio would yield good chloride resistance in concrete under submerged of specimens in a seawater tank environment.

Granular and porous materials based protective layers have proven to be very good shock absorbing medium. Although sand material is widely used (as sand bags) till date in civil and military applications as a blast mitigating medium, fundamental mechanism involved during the impact of shock/blast wave on sand layers is not well understood. This study presents experimental investigations on the impulsive response of sand to extreme loading conditions. A shock tube facility is used to generate a planar shock wave and further the facility is optimized to simulate the properties of a blast wave. This study is divided into three parts based on the type of loading imparted to the sand samples: Shock loading; Air-blast loading; Buried-blast loading. Part one discusses the performance of the sand barrier systems in attenuating the shock waves. The attenuation characteristics of various granular particles (coarse sand, fine sand, glass bead) are investigated by analyzing the reduction in peak overpressure while transmitting through the granular medium. The attenuating capability of the sand barriers has appreciably improved when the outer surfaces of the barriers are retrofitted with a geotextile layer. In the second part, a laboratory-scale experimental approach is presented for evaluating the effects of air-blast on the sand layers. Efforts have been made to study the stress wave propagation in loose and dense sand medium and its direct consequences on the vibrational response. Visualization of the sand deformation is possible with the help of a high-speed camera; displacement trajectories and strains contours are obtained through digital image correlation (DIC) analyses. Part two also reviews the applications of scaled air-blast study on buried pipelines. By using dimensional analysis procedure shock tube experimental results are scaled up to predict the real scale damage imparted to the buried pipes during an air-blast explosion. In addition, a three-dimensional finite element analysis of the test condition is simulated using ABAQUS/Explicit to authenticate the fidelity of the scaling laws. The third part discusses phenomenal aspects associated with the sand deposits when exposed to a buried blast explosion. The focus of this study is to understand the various events involved during the interaction of leading blast wave with the sand medium and characterizing the outburst sand-ejecta. The impulse and peak pressure imparted to the rigid target are evaluated using vertical pendulum and fast response pressure transducers. A parametric study involving different target stand-off distances (SoD) with varied burial depth (DoB) of the blast is presented. Sand ejecta does have a greater influence on the impulse at higher SoDs (>40 mm) and the maximum momentum transfer is observed when SoD to DoB ratio is 2.5.

Hazard Evaluation is an integral part of any process plant, for its smooth running and to avoid accidents, the study of Hazard Identification portrays the picture of all the potential hazards in the design, operation of the plant, which when dealt properly mission and vision of the company can be achieved. There are many Hazard Evaluation Procedures available to identify and assess the hazards. Hazard Evaluation Techniques can be broadly classified into qualitative and quantitative techniques. One such widely accepted technique for identification of Hazards is Hazard Operability Study (HAZOP). Generally, after identifying the hazards using HAZOP technique, identified hazards are then subjected for further evaluation and assessment to decide on the impact of the hazard and as per required changes may be brought. In this Thesis, HAZOP technique has been extensively applied for identifying process hazards of the new Blast Furnace-5 at Rourkela Steel Plant. The Blast Furnace has been divided into sections of Stock House, Pulverized Coal Injection, Hot Blast System, Blast Furnace Proper and Cast House Management. These respective sections have been further divided into nodes, there by investigating the possible causes and consequences for the process deviations in a systematic and logical manner. An attempt has been made to suggest recommendations and include operating difficulties also in the report

My aim in undertaking this research was to identify those specific aspects that would be incorporated within any design process in designing for blast loadings to above ground structures in the Australian environment. Structural engineers are presently forced to use Standards, Codes and Technical Manuals to apply blast loadings to above ground structures during the design process from overseas countries such as America and the United Kingdom. Australian Standards are available to design for design loadings such as dead loads, live loads, wind loads, and earthquake loads but not blast loads. My thesis will investigate and recommend the design criteria as well as design strategies considered applicable for the Australian environment that could be incorporated into an Australian Blast Loading Standard. Blast loadings occur during “Controlled Demolitions” from a deliberately designed explosive demolition (Implosion) of an above ground structure and an “Uncontrolled Demolition” resulting from a bombing event with normally an unknown charge weight and type of explosive. The latter is the most difficult for a structural engineer to design for in advance as he only has past historical events to help him identify the type of explosive that may be used by a bomber within the Australian environment and a charge weight (kg) that is likely to be detonated. In other words, what is the explosive threat from bombings on Australian soil and has it been identified? A detailed literary review covering all aspects of the topic coupled with the use of suitable computer simulation software such as ABAQUS, ELS (Extreme Loading of Structures), LS-DYNA and CONWEP to investigate blast loading of above ground structures was carried out to arrive at suitable recommendations. Although there are suitable and proven overseas codes, standards, etc. that can and are being used extensively within Australia at present to accommodate blast loadings Australia has does not have its own home grown technical documentation to refer to and this is considered unacceptable in 2018. We have never considered and identified the Australian threat in case of an “uncontrolled” demolition (bombing) and by that it is meant what type of explosives would be used (military or civilian) and what is the likely charge weight (kg) that would be detonated against a target. This is unfortunately the case even though we have had several terrorist attacks in Australia since the 1970”s and experienced a major bombing close by in Bali Indonesia in 2002 where many Australians were killed as a result of several bombings with one of particular interest being a 1.02 tonne charge weight car bomb classified as a “homemade” thermobaric (Chan and Meyers, 2005) bomb. The charge in this case was manufactured at home with readily available explosive products purchased locally. With several implosions (controlled demolitions) failing over the years tighter design considerations are needed for the safety of the public. Apart from researching in depth the topic there is a need to articulate the design criteria that applies as well as the strategies that need to be employed to institute such designs in relation to both blast and ballistic loadings. This aspect is particularly critical as designers are using overseas design codes and manuals that may not fit the Australian environment. In other words, we might be importing into our environment designs that are overconservative and inappropriate and susceptible to error during their implementation within designs on Australian soil - why?

A launch vehicle experiences intense acoustic loading in the initial phase of its lift-off due to the noise generated by the rocket exhaust. This affects the launch vehicle structure in addition to sensitive payloads and may result in their failure. The launch vehicle structure has to be specially stiffened to withstand such loading which adversely affects its payload capabilities. Therefore, the mitigation of the lift-off acoustic environment of the launch vehicle is of utmost importance. At lift-off, the components of launch environment such as the launch platform and jet blast deflector contribute to the intense acoustic loads experienced by the launch vehicle by either reflecting the noise generated by the rocket jet exhaust or by creating additional sources of noise. Though the effect of jet blast deflector shape on the acoustic loading has been extensively investigated, contributions from other launch structures such as the launch platform are often ignored. The present work attempts to characterize the acoustic behaviour of the launch platform by simulating a scaled down launch vehicle environment at lift-off, inside an anechoic chamber. The lift-off scenario was simulated by allowing jets from single and twin jet launch vehicle models to impinge on flat plates with and without cut-outs, at varying lift-off distances. The results from the acoustic measurements carried out in the near and far-field of the launch vehicle models show that the presence of the cut-outs have significant effect on the near-field acoustics of the launch vehicle at low lift-off distances(L/De). The acoustic field in the vicinity of the launch vehicle is found to be considerably lower than that obtained when jets impinged on solid flat plates without cut-outs. The influence of the cut-outs, diminishes at higher L/De, when a large fraction of the jet, in addition to flowing through the cut-outs, impinges on the launch platform. The study also explores a new concept of including perforations in the launch platform as a means to attenuate the its contribution to the acoustic levels experienced by the launch vehicle. The inclusion of perforations in the launch platform, decreased the surface area of the launch platform available for jet impingement at higher L/De, thereby reducing the acoustic levels experienced by the launch vehicle at these lift-off distances. The perforated launch platform is found to be effective even with the presence of jet blast deflector, all the way up to 16 nozzle diameters after lift-off. Flow visualizations using schlieren technique indicate that the effectiveness of the perforations stem from the fact that they reduce the strength of the flow features such as wall jets and fountain flow - that are characteristic of jet impingement. The thesis brings out the significant contribution to the lift-off noise from a typical launch platform and the role of flow features like the wall jets and the fountain flow towards noise generation. It is shown that an attenuation of about 4-5 dB can be achieved at L/De>8 by perforating the platform. An optimal design of the launch platform incorporating the perforations can considerably reduce the acoustic loading of the launch vehicle thereby increasing its payload capabilities and ensuring its safety.

The aim of this study was to assess the strength, durability properties and corrosion resistance of concrete samples using supplementary cementitious blended materials. In this investigation, three supplementary concrete materials (SCMs) were used together with ordinary Portland Cement (OPC) to form cementitious blends at different proportions. The supplementary materials are silica fume (SF), ground granulated blast furnace slag (GGBS) and fly ash (FA). Sixteen (16) different proportions of the cementitious blends were produced. Tests carried out on concrete samples include slump test, compressive strength, oxygen permeability, sorptivity, porosity, chloride conductivity test, resistance to chloride and sulphate attack. The electrode potentials of tested samples were also observed using electrochemical measurements. Concrete specimens prepared with 10%, 20%, 30%, 40%, up to 60% of blended cements replacement levels were evaluated for their compressive strength at, 7, 14, 28, 90 and 120 days while the specimens were evaluated for durability tests at 28, and 90 days respectively. The results were compared with ordinary Portland cement concrete without blended cement. Voltage, and temperature measurements were also carried out to understand the quality of concrete. The corrosion performance of steel in reinforced concrete was studied and evaluated by electrochemical half-cell potential technique in both sodium chloride, and magnesium sulphate solutions respectively. The reinforced concrete specimens with centrally embedded 12mm steel bar were exposed to chloride and sulphate solutions with the 0.5 M NaCl and MgSO4 concentrations respectively. An impressed voltage technique was carried out to evaluate the corrosion resistance of the combination of quaternary cementitious blended cement, so as to get the combination with optimum performance. Improvement of strength, durability, and corrosion resistance properties of blended concrete samples are observed at different optimum percentages for binary, ternary and quaternary samples. The effect of cementitious blends is recognized in limiting the corrosion potential of the tested SCM concrete samples. Generally, the cementitious blends with limited quantity of SF to 10% have the potential to produce satisfactory concrete. These should however be used for low cost construction, where high quality concrete is not required.
Civil and Chemical Engineering
M. Tech. (Chemical Engineering)