Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and, (M.S.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 124-127. / by Enrique J. Laya. / M.S.

This thesis presents a research effort aimed at developing a stronger, lighter, and more economic shelter using rigid wall panels. Reported herein is insulation research, wall and roof panel design and testing, floor section modeling and strength calculations, and cost and weight calculations. Beginning stages focus on developing solid wall and roof panels using cold-formed steel corrugated sheathing and members, as well as polyurethane spray foam for insulation. This research includes calculating uniform load density, to determine the overall strength of the panel. The next stage focuses on the flexural strength of the wall and roof panels, as well as finalizing the floor design for the shelter. This includes determining maximum flexural strength required to meet the standards set by the project goal. Direct strength method determined the correct thickness of members to use based on the dimension selected for the design. All Phases incorporated different connection methods, with varied stud spacing, to determine the safest design for the new shelters. Previous research has shown that cold-formed steel corrugated sheathing performs better than thicker flat sheathing of various construction materials, with screw and spot weld connections. Full scale shear wall tests on this type of shear wall system have been conducted, and it was found that the corrugated sheathing had rigid board behavior before it failed in shear buckling in sheathing and sometimes simultaneously in screw connection failures. Another aspect of the research is on the insulation of the wall panels. Research was conducted on many different insulation options for the mobile facilities. Specifically, insulation made of lightweight material, is non-combustible, added rigidity to the structure, and has high thermal properties. Closed cell polyurethane spray foam was selected for full-scale testing in this research. Closed cell polyurethane adds extra rigidity, is lighter than common honeycomb insulation, and has a higher R-value. Several polyurethane foam companies were studied for this research, and promising products were identified. The research focuses on the impacts of the polyurethane foam to the structural performance of the wall panels. Both shear and 4-point bending tests were completed to investigate the strength and behavior of the cold-formed steel framed wall panels with polyurethane foam insulation. Comparing the cost and weight of the current shelter, and the new design is reported herein. The material studies, specimen details, and test results are reported in this thesis.

M. Tech. (Department of Metallurgical Engineering, Faculty of Engineering and Technology), Vaal University of Technology. / During steel production, a large quantity of waste residue commonly known as slag is produced with a reasonable amount of metals such as calcium and magnesium. Iron and steel slags have various economically viable applications such as fertiliser production, cement production, road construction, land fill and soil reclamation. However, other applications respond to the issue of controlling and degrading high levels of anthropogenic carbon dioxide (CO2) gas emissions by carbonating calcium and magnesium leach solutions from iron and steel slags. One such technological method is the extraction of calcium by means of leaching from iron and steel slag whereby CO2 sequestration is a long-term goal. In contrast, calcium and magnesium leach solutions can produce precipitated carbonates for various uses when carbonated. In addition, it is a crucial step to study the leaching parameters and reliable solvents for the dissolution of calcium and magnesium owing to their contents in iron and steel slags. The aim of this research project was to determine the physico-chemical factors affecting leaching of calcium from blast furnace slag and thereby improve the extent and kinetics of calcium extraction. The chemical and mineralogical study by X-ray fluorescence (XRF) and X-ray diffraction (XRD) respectively, has shown that the blast furnace slag sample under study contained calcium in the form of aluminoakermanite ((Ca,Na)2(Al,Mg,Fe2+)). The minerals identified through XRD are classified as silicates with the host mineral being calcium in recoverable quantities. The initial XRF analysis showed that the slag contained 23.47% Ca, 5.21% Mg and 1.24% Fe with the rest being minor elements. The slag was received at a particle size of 20 mm. Size reduction was conducted in a dry rod mill process to produce a size of 80% -75μm. Particle size distribution was analysed by a simple laboratory sieving method. The leaching tests were conducted in an incubated orbital shaker by applying the one-factor-at-a-time method for a two-hour leaching test. Reaction temperature was controlled at 30, 50, 70 and 100˚C. Ionic strength varied at 0.5, 1.0, 1.5 and 2.0 molar (M). In addition, the solid/liquid ratio was observed in the range 200, 300, 400 and 600 gram/Litre (g/L). Acetic acid (CH3COOH), ammonium sulphate ((NH4)2SO4) and ammonium chloride (NH4Cl) were tested individually as lixiviants under varying temperatures, ionic strengths and solid/liquid ratio. The results showed that extraction of calcium from ironmaking slag by leaching is feasible. 100% Ca was extracted using CH3COOH at 100˚C, 0.5 M, 200 g/L and 120 minutes. As the reaction temperature was increased from 50˚C up to 100˚C, silica gelling was observed, which hindered filtration of a leach liquor from a residue. Silica gelling did not compromise calcium recovery. The increase in lixiviant ionic strength and solid-liquid ratio did not influence calcium recovery. The role of anions during leaching by using ammonium sulphate, ammonium chloride and acetic acid as lixiviants was identified. Sulphate ions were found to have the least influence in the increase in calcium recovery. Acetate ions have a significant role on dissolution of calcium as well as chloride ions. Consequently, the findings showed that temperature is the critical operating parameter that yielded exceptionally high calcium extraction percentages. CH3COOH yielded 80%-90% of calcium extracted under high reaction temperatures. The kinetic data for the effect of reaction temperature leaching data fitted one shrinking core model equation, which described diffusion-controlled leaching reactions. The diffusion controlled by a product layer model was fitted and the activation energy were calculated as 19.4930 kJ/mol for NH4Cl solvent. (NH4)2SO4 and CH3COOH did not fit into any model because of undefined kinetic data and formation of gelatinous silica layer during leaching process. The Arrhenius equation, confirmed that the leaching reaction by NH4Cl solvent fitted diffusion-controlled mechanism.

Developing a rational method of design has long been the goal of structural engineering. For steel structures, through the development of plastic design and electronic computation, this now seems possible. Several methods have been proposed within the last five years, and one method has been programmed for the digital computer. Five methods are here discussed and compared and the method of Heyman and Prager is investigated in detail. The assumptions and restrictions of the Heyman-Prager method, along with the computer program developed by Kalker, are investigated and discussed. The author attempts to evaluate the usefulness of, and place the Heyman-Prager method in a proper perspective in the overall planning, design, analysis phases of the total structural evolution. It is concluded that a more efficient computer program could be developed to facilitate the structural solution and some methods by which this might be accomplished are suggested. A comprehensive bibliography is provided which traces the development of practical minimum weight, plastic design from its inception up to the present time. / Master of Science

No description available.

Civil infrastructure throughout the world serves as main arteries for commerce and transportation, commonly forming the backbone of many societies. Bridges have been and remain a crucial part of the success of these civil networks. However, the crucial elements have been built over centuries and have been subject to generations of use. Many current bridges have outlived their intended service life or have been retrofitted to carry additional loads over their original design. A large number of these historic bridges are still in everyday use and their condition needs to be monitored for public safety. Transportation infrastructure authorities have implemented various inspection and management programs throughout the world, mainly visual inspections. However, careful visual inspections can provide valuable information but it has limitations in that it provides no actual stress-strain information to determine structural soundness. Structural Health Monitoring (SHM) has been a growing area of research as officials need to asses and triage the aging infrastructure with methods that provide measurable response information to determine the health of the structure. A rapid improvement in technology has allowed researchers to start using new sensors and algorithms to understand the structural parameters of tested structures due to known and unknown loading scenarios. One of the most promising methods involves the use of wireless sensor nodes to measure structural responses to loads in real time. The structural responses can be processed to help understand the modal parameters, determine the health of the structure, and potentially identify damage. For example, modal parameters of structures are typically used when designing the lateral system of a structure. A better understanding of these parameters can lead to better and more efficient designs. Usually engineers rely on a finite element analysis to identify these parameters. By observing the actual parameters displayed during field testing, the theoretical FE models can be validated for accuracy. This paper will present the field testing of a historic wrought iron truss bridge, in a case study, to establish a repeatable procedure to be used as reference for the testing of other similar structures.

Thesis (MBA)--Stellenbosch University, 2006. / ENGLISH ABSTRACT: In South Africa more people are living with AIDS than in any other country in the world. It is now evident that HIV/AIDS has developed into a pandemic that not only affects the health of individuals, but does expand to households, communities and the nation. The stigma of HIV/AIDS is most likely the single most important reason why people, organisations and the government tend to shy away from the problem. The prime aim of business is to make money, but the fact that AIDS affects people at the peak of their productive years when they would normally not require medical attention, will impact negatively on the organisation's bottom line results. Apart from government, business is the only group that has the capacity and resources to successfully implement strategies in the fight against HIV and AIDS. This study provides a theoretical introduction to HIV and AIDS but also indicates that small to medium size organisations are slow to react to the threat that HIV and AIDS will have to their business and also the country. The study shows that large organisations have definitely been successful in their fight against the disease. The study concludes that knowing the prevalence rate of HIV in a organisation and adapting the strategy accordingly is essential for long term sustainability of the organisation. CISCO was selected as the case study to substantiate the above-mentioned opinions and conclusions. / AFRIKAANSE OPSOMMING: In Suid Afrika woon daar meer mense met VIGS as enige in enige ander land in die wereld. Dit is tans duidelik dat MIV/VIGS ontwikkel het in 'n pandemie wat nie net die gesondheid van individue raak nie, maar wat ook uitkring na huishoudings, gemeenskappe en die nasie. Die stigma van MIV/VIGS is heel waarskynlik die grootste enkele rede waarom organisasies en die regering wegskram van die probleem. Die hoofdoel van 'n besigheid is om wins te maak, maar die feit dat VIGS mense tydens die toppunt van hulle produktiewe jare affekteer wanneer hulle normaalweg geen mediese versorging sou benodig nie, gaan 'n negatiewe effek op organisasies se winsgewendheid hê. Behalwe vir die regering is privaat besighede die enigste groep wat beskik oor die kapasiteit en hulpbronne om strategiee te implimenteer wat suksesvol sal wees in die stryd teen MIV en VIGS. Hierdie studie gee 'n teoretiese inleiding oor MIV en VIGS. Dit dui ook daarop dat klein tot medium grootte organisasies stadig reageer op die bedreiging wat MIV en VIGS vir hul besigheid en die land kan inhou. Die studie toon dat groter organisasies meer sukses behaal in hulle stryd teen die siekte. Die studie bevind dat dit vir die volhoubaarheid van 'n organisasie belangrik is om te weet wat die voorkoms syfers van MIV in die organisasie is en die strategie ten opsigte van MIV en VIGS dienooreenkomstig aan te pas. CISCO is as 'n gevallestudie gebruik om bogenoemde waarnemings en aanbevelings te staaf.

Thesis (MScEng (Civil Engineering))--Stellenbosch University, 2008. / The Southern African Institute of Steel Construction expressed concern with regard to the unit definition of the effective length factor, K, stipulated for compressive elements of parallel chord trusses in Clause 15 of SANS 10162-1:2005 - Limit state design of hot-rolled steelwork. The simplified method for truss design specified in the code assumes all compression members are pin-connected, which allows for greater design simplicity and reduces the amount of code interpretation required by the designer. In addition to this, Clause 15 requires the additional reduction in resistance of the first web compression members by a factor of 0.85. However, this approach may be considered overly conservative and in current design practice the effective length factor is often reduced to less than 1.0. This research investigates the effective length factor of web compression members in parallel chord trusses, by means of investigative structural analyses of representative trusses using ANGELINE and Prokon analytical programs, and by designing, constructing and testing six representative trusses, using current design practices. A comparative study of a number of different countries’ codified approaches to truss design is also included. The structural analyses revealed that in-plane buckling of the web compression members was the consistent mode of failure, however at a much greater applied load than the design load determined according to SANS 10162-1:2005. Contrary to the expected mode of failure, all six tests performed on the representative trusses exhibited elastic out-of-plane buckling, or strongaxis buckling, of the web compression members, but still at a much greater applied load than the design load. The unexpected out-of-plane buckling of the web members is due to the inplane stiffness of the end connections used. In order to stay true to current design practice, gusset plates and longitudinal welds were used to join the web members to the chords. The stiffness of the gusset plates therefore significantly reduced the effective length of the web compression members in-plane, but did not reduce the effective length out-of-plane. Despite the unanticipated behaviour of the tests performed, certain conclusions can still be drawn from the results. The unit definition of the effective length factor for in-plane buckling of web compression members is too conservative and a K factor of 0.8 is recommended. In addition to this an effective length factor for out-plane-buckling of web compression members of 1.1 is recommended for trusses with welded connections. The necessity of the reduction in resistance of 0.85 of the first web compression members requires further investigation. The most important conclusion to be drawn is that out-of-plane buckling of web compression members can be the dominant failure mode, which is not taken into consideration in current design practice.

The dissertation is a biography of the industrialist and statesman Christian Lundeberg, a leading and stongly pronounced conservative actor in Swedish political life during the decades around1900, but nowadays almost forgotten. The purpose is to identify the main forces – convictions as well as external factors – behind his actions. He was very influential within  a range of important sectors, i.a. compulsory national service, repeated interventions to keep the iron ore of Norrland under Swedish ownership,  establishment of a regular conservative party and the decision on the vote to right (for men) in 1907. His most well-known action was as Swedish Prime Minister and head architect behind the peaceful dissolution in 1905 of the union with Norway. However for a long time biographies have not been regarded as ”real” scientific work within the concerned academic Swedish circles. For this reason the introductory chapter analyses these discussions  and  concludes that time now is ready for the genre to come in from the cold , enumerating six criteria regarded to be of paramount importance. These are being observed in the consecutive parts of the study. The following chapter studies the concept of paternalism as defined within Swedish professional circles, forming a background to the remaining parts of the dissertation. In their turn these present thorough reviews both of Lundeberg’s activities as a paternalistic foundry proprietor in the local family owned community of Forsbacka and of his contributions on the central political level. The final chapter summarizes the driving forces behind Lundeberg’s activities in stating that he was not an ultraconservative person, a priori opposing all progress.  Instead as the years passed he developed a clear readiness for compromise solutions. Three key concepts are said to be central to the understanding of his person: “Fatherland”, ”Responsibility” and “Duty”.  Throughout all his life he adhered to many of the paternalistic principles and values he learnt at an early age in Forsbacka. His present anonymity is explained  by the fact that he in a retrospective very often is considered as being defeated in a number of political convictions now regarded as important.

The iron and steel industry has become increasingly globalised. Market conditions are also changing and de-carbonisation of production is challenging. The objective of this thesis is to assess how energy efficiency and greenhouse gas emissions reductions can be promoted and effectively monitored in the steel industry. The thesis contributes with analyses based on the Malmquist Productivity Index for a top-down analysis of the energy efficiency of EU Member States’ iron and steel production, and Partial Least Squares regression for bottom-up assessments of different monitoring tools. The thesis also contributes with a scrap availability assessment module to enhance the energy system model ETSAP-TIAM. The first phase of the research showed that future production needs to shift towards innovative low-CO2 technologies even when all available recycled material is fully used. Techniques using carbon capture and storage (CCS) as well as hydrogen-based technologies can be expected to become economically viable under tightened climate policies. The second phase of the research showed that current indicators are insufficient. System boundaries of energy use and emissions data do not align with production statistics. Indicators based on energy use or emissions in relation to production in physical terms may be useful to track specific processes. However, current indicators fail to reflect the companies’ product mix. Enhanced energy and climate indicators that adjust for the product mix provide better estimates while failing to reflect the increasing globalisation. Effective monitoring of industrial transformation will be increasingly important as pressure from climate policy via global CO2-pricing is unlikely in the short term. Current or enhanced indicators do not fully capture industrial transformation and are not recommended. Future research should focus on defining indicators to estimate energy use and emissions along industrial value chains in climate policy contexts. / Järn- och stålindustrin har blivit alltmer globaliserad. Marknadsvillkoren förändras samtidigt som utfasningen av fossila bränslen är utmanande. Målet med den här avhandlingen är att bedöma hur energieffektivitet och växthusgasutsläppsminskningar kan främjas och effektivt utvärderas inom stålindustrin. Avhandlingen bidrar med analyser baserade Malmquists produktivitetsindex för att analysera energieffektivitet av EU:s medlemsstaters järn- och stålproduktion, och partiell minsta- kvadrat-regression för att bedöma olika utvärderingsmått. Avhandlingen bidrar även med en modul som bedömer skrottillgång för att förbättra energisystemmodellen ETSAP-TIAM. I en första fas visade forskningen att framtida produktion behöver ställas om mot innovativa teknologier med låga CO2-utsläpp även när allt tillgängligt återvunnet material används fullt ut. Tekniker som använder koldioxidinfångning och -lagring (CCS) samt vätebaserade teknologier kan förväntas bli ekonomiskt försvarbara under åtstramade klimatpolitiska styrmedel. I en andra fas visade forskningen att nuvarande indikatorer är otillräckliga. Systemgränser för energianvändnings- och växthusgasutsläppsdata stämmer inte överens med produktionsstatistik. Indikatorer utifrån energianvändning eller utsläpp i relation till fysisk produktion kan vara användbara för att följa upp specifika processer. Nuvarande indikatorer lyckas dock inte spegla företagens produktmix. Förbättrade energi- och klimatindikatorer som justerar för produktmixen ger bättre uppskattningar, men speglar inte branschens ökande globalisering. Effektiv utvärdering av industriell transformation blir alltmer viktig då påtryckning från klimatpolitiska styrmedel via global CO2-prissättning är kortsiktigt osannolik. Nuvarande eller förbättrade indikatorer fångar inte industriell transformation fullt ut och rekommenderas inte. Framtida forskning bör fokusera på att definiera indikatorer som uppskattar energianvändning och växthusgasutsläpp längs industriella värdekedjor. / <p>QC 20170428</p>