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1
Yesuf, Jemil N. "EVALUATION OF CELLULOLYTIC ENZYMES FROM A NEWLY ISOLATED BREVIBACILLUS SP. JXL; AND OPTIMIZATION OF COSLIF PRETREATMENT VARIABLES OF SWEET SORGHUM BAGASSE USING A RESPONSE SURFACE METHOD." OpenSIUC, 2012. https://opensiuc.lib.siu.edu/dissertations/515.
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The first part of the dissertation presented a potentially novel aerobic, thermophilic, and cellulolytic bacterium identified as Brevibacillus sp. Strain JXL which was isolated from swine waste. Strain JXL can utilize a broad range of carbohydrates including: cellulose, carboxymethylcellulose (CMC), xylan, cellobiose, glucose, and xylose. In two different media supplemented with crystalline cellulose and CMC at 57°C under aeration, strain JXL produced a basal level of cellulases as FPU of 0.02 IU/ml in the crude culture supernatant. When glucose or cellobiose was used besides cellulose, cellulase activities were enhanced ten times during the first 24 h, but with no significant difference between the effects caused by these two simple sugars. After the end of the 24 hour period, however, culture with glucose demonstrated higher cellulase activities compared with that from cellobiose. Similar trend and effect on cellulase activities were also observed when glucose or cellobiose served as a single substrate. The optimal doses of cellobiose and glucose for cellulase induction were 0.5 and 1%. These inducing effects were further confirmed by scanning electron microscopy (SEM) images, which indicated the presence of extracellular protuberant structures. These cellulosome-resembling structures were most abundant in culture with glucose, followed by cellobiose and without sugar addition. With respect to cellulase activity assay, crude cellulases had an optimal temperature of 50°C and optimal pH range of 6-8. These cellulases also had high thermotolerance as demonstrated by retaining more than 50% activity after 1 h at 100°C. In summary, this is the first study to show that the genus Brevibacillus may have strains that can degrade cellulose. In the second part of the dissertation, the effect of Cellulose- and Organic-Solvent based Lignocellulose Fractionation (COSLIF) (Zhang, Y.-H. P.; Ding, S.-Y.; Mielenz, J. R.; Elander, R.; Laser, M.; Himmel, M.; McMillan, J. D.; Lynd, L. R. Biotechnol. Bioeng.2007, 97 (2), 214−223) pretreatment conditions on sweet sorghum bagasse (SSB) feedstock was studied using Response Surface Methodology (RSM). Batch experimental matrix was set up based on response surface method's central composite design in two factors to determine the effects of reaction time and temperature on the yield of simple sugars after a sequential pretreatment-enzyme hydrolysis process. Accordingly, changes in delignification, total reducing sugar (TRS) yield, glucan retention, digestibility and overall sugar yields resulting from various combinations of reaction times and temperatures were determined. The results suggested that both pretreatment temperature and reaction time were significant factors, although temperature was more so than reaction time. COSLIF pretreatment conditions of 50°C and 40 min were found to be the optimum pretreatment conditions for the saccharification of SSB. At the end of pretreatment and enzymatic hydrolysis, maximum values of 51.4% delignification, 85% overall glucose yield, and 44% overall xylose yield at an ACCELERASE®1500 loading of 0.25 mL/g sweet sorghum bagasse were achieved. Optimum ACCELERASE®1500 dosage of 0.1 mL/g of sweet sorghum bagasse was identified which resulted in an overall glucose yield of 82.2%±1.05. An effort has also been made to prescribe predictive models which represented the correlation between independent variables (reaction time and temperature), and dependent variables (delignification, and overall glucose yield) using RSM. The significance of the correlations and adequacy of these models were statistically tested for the selected objective functions. The outcomes suggested very competent and statistically adequate regression models which provided quantitative information both for delignification and overall glucose yield for the batch experiments studied.
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Shrestha, Santosh. "A COMPARATIVE STUDY OF EQUIVALENT LATERAL FORCE METHOD AND RESPONSE SPECTRUM ANALYSIS IN SEISMIC DESIGN OF STRUCTURAL FRAMES." OpenSIUC, 2019. https://opensiuc.lib.siu.edu/theses/2561.
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Equivalent Lateral Force Method (ELF) and Response Spectrum Analysis (RSA) are the two most popular methods of seismic design of structures. This study aims to present a comparative study of the two methods using hand-calculated approach as well as computer analysis according to ASCE 7-10 Standards. The two methods have been compared in terms of base shear and story forces by analyzing various models for different number of stories and different support conditions. It was found that ELF gives conservative results in comparison to RSA. This result was more obvious in case of four-story frames. Hence, for structures of increased elevation, the analysis from ELF may not be sufficient.
3
Yang, Yan. "Nonstructural component field testing method for the evaluation of seismic demand incorporating floor response spectrum." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/46567.
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Nonstructural component (NSC) failures due to earthquake events can cause significant economic losses and even life-threatening hazards to occupants. In order to mitigate nonstructural seismic damages, it is critical to assess the seismic force demand which can be utilized to optimize the design of the NSC, and/or to assess methods of rehabilitation on anchorages to enhance seismic strength.
The existing design codes and standards provide guidelines to calculate the minimum lateral earthquake force for designing a new NSC. However, they do not reflect the in-service condition of an existing NSC, which can vary significantly from when it was first installed. This study is intended to develop an easy-to-implement methodology to assess the seismic force demand of an existing NSC under normal operation.
The procedure of the proposed methodology includes two principle phases: 1) field modal identification testing and 2) floor response spectrum analyses using a 3D finite element model (FEM). The practicality of this methodology was assessed through a case study on the U.B.C Hospital Koerner Pavilion building. In this study, the focus is on the machinery and equipment that are critical for the operation of a hospital. During the experimental stage, the fundamental frequencies and damping ratios of eight NSCs were identified. In the second phase, the horizontal floor response spectra (FRS) were constructed from the linear time history analysis results performed on a FEM. Finally, the FRS is used to obtain the lateral seismic force of each NSC corresponding to its dynamic properties. These forces were then compared with those obtained using the NBCC 2010 code equation to demonstrate the effectiveness of this method.
Results from the case study provided evidence that the proposed method is overall a simple and effective tool for diagnosing the in-service modal properties of a NSC. The testing results can be easily applied in FRS analysis to obtain a more realistic nonstructural seismic force than that from the NBCC 2010 approach. The potential applications and limitations of the proposed methodology are also discussed in this dissertation to facilitate engineers to determine the suitability of this method to their specific projects.
4
Doupník, Petr. "Využití optimalizačních metod při návrhu transsonického křídla s implementací základních konstrukčně pevnostních omezení." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-233939.
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The thesis gives overview of complex aerodynamic optimization approach applied to business-jet aircraft wing design. Response surface method (RSM) potential was explored particularly. The efficiency of RSM approach for CFD based aerodynamic optimization was demonstrated. Basic structural requirements were successfully integrated to optimization – real multidisciplinary problem was solved. Some methods for evaluation of forces distribution along wingspan were explored. Thesis was solving within the frame of 6th EU FP integrated project CESAR.
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Pleva, František. "Metoda odezvových ploch ve spojení s CFD pro tvarovou optimalizaci." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-449797.
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This thesis is focused on shape optimization of Venturi´s nozzle with optimization method called response surface method. The first part of this work is concerned with the description of this method as well as explaining the basic principle. Furthermore, there is an explanation of the application of this method in synchronicity with CFD and its operating algorithm. The second part of this thesis is then focused on simple example with plane wing and simplified optimization of Venturi´s nozzle in which this method was tested. In the third part there is described full multiparameter shape optimalization of the nozzle for two geometries.
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Benvenutti, Laís. "AVALIAÇÃO DA EXTRAÇÃO DE COMPOSTOS FENÓLICOS DO BAGAÇO DE MAÇÃ COM ETANOL PARA APLICAÇÃO EM SIDRA." Universidade Estadual de Ponta Grossa, 2018. http://tede2.uepg.br/jspui/handle/prefix/2465.
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Previous issue date: 2018-02-02<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>A maçã apresenta alta concentração de compostos fenólicos, distribuídos em
diferentes classes as quais apresentam capacidade antioxidante. Além disso,
conferem efeito positivo na formação do sabor, cor e aroma em bebidas derivadas
da fruta. No entanto, durante o processamento, parte da composição fenólica fica
retida no bagaço, principal subproduto da agroindústria da maçã. Desta forma, este
trabalho teve como objetivo a otimização da extração de compostos fenólicos
presentes no bagaço da maçã utilizando solvente de grau alimentício, visando sua
aplicação em sidras a fim de melhorar as características tecnológicas, nutricionais e
sensoriais do produto final. Nos ensaios de extração foram avaliados os efeitos da
concentração de solvente (etanol), temperatura e razão sólido/líquido sobre o
rendimento e atividade antioxidante dos extratos, utilizando o método de superfície
de resposta (MSR). Além disso, foi estudada a cinética da extração, bem como a
estabilidade do extrato. A análise de regressão linear múltipla acoplada ao MSR
sugeriu que a extração seja efetuada utilizando etanol 60%, a 50 °C, na razão
sólido/líquido de 1:20 (m/v). Por meio de um modelo cinético de primeira ordem
foram avaliados os efeitos do tempo e da temperatura sobre a concentração de
equilíbrio da extração, a qual foi atingida aproximadamente aos 50 minutos,
independente da temperatura, com teores de 1852,77; 1728,35 e 1265,29 mg
CAT/kg para as temperaturas de 50, 35 e 20 °C, respectivamente. A partir desses
resultados, a energia de ativação necessária para que ocorra a transferência do
soluto foi 9,01 kJ/mol. Em geral, os flavonoides apresentaram boa estabilidade
durante período de 90 dias, sendo sugerido armazenamento ou aplicação sob
temperatura de 10 °C em pH de aproximadamente 3,5. O extrato obtido nas
melhores condições foi adicionado ao mosto antes do inóculo de levedura e a
fermentação foi monitorada por meio do estudo cinético. Os mostos e pontos da
fermentação (1, 4, 7, 11 e 15 dias) foram avaliados quanto aos fenóis individuais,
açúcares e etanol em cromatografia líquida de alta eficiência (CLAE). Além disso, foi
avaliada a composição fenólica total, flavonoides totais, flavanóis, flavonóis e
atividade antioxidante, bem como, o teor de acidez total titulável, pH e cor. Os
produtos finais foram analisados sensorialmente quanto à intensidade de cor, acidez,
adstringência e amargor por meio de uma escala estruturada, e quanto à qualidade
do odor em escala hedônica de aceitação. A adição do extrato aumentou cerca 40%
a concentração de flavonoides totais, apresentando glicosídeos de quercetina,
compostos presentes apenas no epicarpo da maçã, os quais foram um dos
compostos relacionados com o aumento da atividade antioxidante na sidra com
adição de extrato. A adição do extrato também resultou em maior intensidade de cor
e percepção do amargor e adstringência. Apesar das alterações na composição
fenólica, a adição do extrato não prejudicou a qualidade do odor do produto final.
Portanto, o extrato fenólico obtido com etanol em condições otimizadas foi capaz de
reincorporar parte dos compostos bioativos retidos no bagaço, aumentando a
capacidade antioxidante e alterando características sensoriais responsáveis pela
aceitabilidade da bebida.<br>Apple has high amounts of phenolic compounds, distributed in different classes
which show antioxidant capacity. In addition, the phenolic compounds contribute to
flavor, color and aroma in apple beverages. However, most of the phenolic
compounds, especially the flavonoids, are retained in the apple pomace, during
processing. In this way, this work aimed to optimize the flavonoids extraction from
apple pomace using food grade solvent, and to apply the extracts in ciders in order to
improve the technological, nutritional and sensorial characteristics of the final product.
In the extraction experiments, the effects of solvent concentration (ethanol),
temperature and solid/liquid ratio on process yield and antioxidant activity of the
extracts were evaluated using response surface methodology (RSM). In addition, the
extraction kinetics as well as the stability of the extract were studied. The multiple
linear regression analysis coupled to RSM suggested that the extraction be
performed using ethanol 60% at 50 °C and with solute-solvent ratio of 1:20 (w/v). The
effects of time and temperature on the equilibrium concentration of the extraction
were evaluated, which was reached at approximately 50 minutes with contents of
1852.77; 1728.35 and 1265.29 mg CAT/kg for the temperatures of 50, 35 and 20 ° C,
respectively. The activation energy required for solute transfer to occur was
determined, 9.01 kJ mol-1. In general, the flavonoids showed good stability during the
period of 90 days, being suggested its storage or application under a temperature of
10 °C and pH about 3.5. The extract obtained under the best conditions was added
to the must prior to addition of the yeast inoculum and the fermentation was
monitored by kinetic study. The musts and ciders (1, 4, 7, 11 and 15 days) were
evaluated as to the individual phenols and sugar and ethanol contents were
quantified in high performance liquid chromatography (HPLC). In addition, the total
phenolic composition, total flavonoids, flavanols, flavonols and antioxidant activity, as
well as total titratable acidity, pH and color were evaluated. The final products were
sensorially analyzed for color intensity, acidity, astringency and bitterness by means
of a structured scale. The odor quality was evaluated in a hedonic scale of
acceptance. The addition of the extract increased about 40% in the total flavonoid
content. Quercetin glycosides, compounds present only in the apple epicarp, were
found, being one of the compounds associated for the increase in antioxidant activity.
The cider with the extract addition showed higher intensity of color and perception of
the bitterness and astringency. Despite the changes in phenolic composition, the
addition of the extract did not affect the odor quality of the final product. Therefore,
the phenolic extract obtained with ethanol under optimized conditions was able to
reincorporate bioactive compounds retained in the pomace, increasing the
antioxidant capacity and changing sensorial characteristics responsible for the
acceptability of the beverage.
7
Kinali, Kursat. "Seismic Fragility Assessment of Steel Frames in the Central and Eastern United States." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14528.
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The Central and Eastern United States (CEUS) is a region that is characterized by low frequency-high consequence seismic events such as the New Madrid sequence of 18111812. The infrequent nature of earthquakes in the region has led to a perception that the seismic risk in the area is low, and the current building stock reflects this perception. The majority of steel-framed buildings in the CEUS were designed without regard to seismic loads. Such frames possess limited seismic resistance, and may pose an unacceptable risk if a large earthquake were to occur in the region. A key ingredient of building performance and seismic risk assessment is the fragility, a term that describes the probability of failure to meet a performance objective as a function of demand on the system. The effects of uncertainties on building seismic performance can be displayed by a seismic fragility relationship. This fragility can be used in a conditional scenario-based seismic risk assessment or can be integrated with seismic hazard to obtain an estimate of annual or lifetime risk. The seismic fragility analyses in this study focus on steel frames that are typical of building construction in regions of infrequent seismicity; such frames have received little attention to date in building seismic risk assessment. Current steel building stock in Shelby Co., TN has been represented by five code-compliant model frames with different lateral force-resisting systems, i.e., braced-frames, partially-restrained moment frames and a rigid moment frame. The performance of model frames under certain hazard levels was assessed using fragility curves. Different rehabilitation methods were discussed and applied. Results indicate that PR frames behave better than expected and rehabilitated frames perform quite well even under severe earthquakes.
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Čapičík, Martin. "Seismická analýza čerpadla 200-QHD." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231287.
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The main goal of this thesis is dynamic analysis of shaft of booster pump QHD-200. In the beginning we offer basic equations generally used in dynamics and common/possible methods for their solution. Then we focus on specific problems connected with rotor dynamics and using simple Laval rotor we show their mathematical interpretation. Based on given load as accelerogram we create response spectrum in different ways (using different methods) and compare their CPU time demand. In the next part we make three finite element models of different physical level. We perform modal analysis and comparison of eigen frequencies, mode shapes. In following chapter transient analysis was performed on all models. As load we use accelerogram. We evaluate translations in particular positions of model. After that, we decide whether or not gap between impeller and stator case will be erased. Finally we make assessment of force acting upon bearings.
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Navrátilová, Martina. "Nelineární dynamická analýza konstrukce zatížena seismickými účinky." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227701.
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Diploma thesis compares the methods for the calculation of the response of structures with seismic loads. Linear and nonlinear analyses are used for the calculations. In the case of linear analysis response spectrum method is applied. For nonlinear analysis pushover method is used. These two methods are compared in programs AxisVM and RFEM on the examples of high-rise building and space frame.
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Badaoui, M'Hammed. "Influence de l'hétérogénéité géologique et mécanique sur la réponse des sols multicouches." Phd thesis, Université Paris-Est, 2008. http://tel.archives-ouvertes.fr/tel-00462182.
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Dans cette thèse nous nous sommes intéressés à établir une formulation probabiliste pour l'analyse du comportement d'un sol multicouche avec des caractéristiques aléatoires. Deux grands axes sont traités : ?la consolidation primaire et ?la réponse sismique des sols multicouches ayant des caractéristiques aléatoires. Nous utilisons les simulations de Monte Carlo associées à des méthodes semi-analytiques adaptées aux sols multicouches avec une stratification horizontale. Nous avons aussi comparés les résultats obtenus à partir de cette formulation à ceux fournis par les règlements parasismiques suivants : RPA 99 (version 2003), UBC 97 et l'EC8. Cette étude a montré que les valeurs maximales des forces de cisaillement à la base des bâtiments variaient substantiellement en fonction de la variation de la hauteur du profil de sol ainsi que de son hétérogénéité pouvant atteindre un rapport relatif de l'ordre de 3 dans les cas les plus défavorables. Ce rapport peut également être inférieur à 1 conduisant à des structures moins économiques
11
Ezeddini, Sonia. "Optimisation de l'usinage par le procédé d'électroérosion à fil des alliages de titane et des matériaux composites à base de titane appliqués à l'aéronautique." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLC105.
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L’usinage par électroérosion est un procédé d’enlèvement de matière par fusion, vaporisation et érosion, réservé aux matériaux conducteurs et semi-conducteurs.Il peut être utilisé pour usiner les métaux et alliages, les aciers trempés, les alliages céramiques, les carbures métalliques, certaines céramiques et même des matériaux plus durs tels que le diamant polycristallin. La pièce ainsi chauffée voit ses caractéristiques mécaniques chuter et modifier, ce qui augmente son usinabilité. Les travaux réalisés ont porté sur l'influence de l'usinage par électroérosion à fil sur; l'intégrité de surface, l'usinabilité, la productivité et la précision de procédé, de plusieurs matériaux, tels que, le titane pur, l'alliage de titane Ti-6Al-4V, le composite intermétallique à base Ti-Al, le composite Ti17 et le composite Ti6242.En usinage par électro-érosion à fil, et plus précisément en finition, le procédé est caractérisé par un débit de matière, une largeur de kerf, un durcissement superficiel, une zone affectée thermiquement et un état de surface variant en fonction de plusieurs paramètres tels que, le courant de décharge, le temps d’impulsion, la tension d’amorçage, la vitesse de coupe, la pression d'injection de lubrifiant et la tension de fil.Toutefois, il s’agit d’une étude d’optimisation et de modélisation empirique des conditions de coupe des matériaux composites à base métallique et des alliages de titane, afin de maitriser et d'améliorer l'intégrité de surface usinée, d'augmenter la productivité et de perfectionner la précision du procédé. Par la suite, atteindre les exigences de la qualité et de la sûreté de fonctionnement des pièces aéronautiques.Dans cette étude, on a utilisé des méthodes de type Plan d'expériences, méthode de Taguchi et la Méthodologie des surfaces de réponses pour le calage et le contrôle des paramètres de l’usinage par électroérosion à fil, et ses conditions opératoires<br>EDM machining is a process for the removal of material by melting, spraying and erosion, which is reserved for conductive and semiconductor materials.It can be used for machining metals and alloys, hardened steels, ceramic alloys, metal carbides, some ceramics and even harder materials such as polycrystalline diamond. The heated part has its mechanical characteristics drop, which increases its machinability. The work carried out focused on the influence of WEDM machining on surface integrity, machinability, productivity and process precision, of several materials: pure titanium, Ti6Al4V alloy, composite intermetallicTi-Al based, Ti17 composite and Ti6242 composite.In ripping, and more precisely in finishing, the process is characterized by a flow of material,kerf width, surface hardening, heat affected zone and surface condition varying with discharge current, pulse time and voltage, cutting speed, lubricant injection pressure and wire tension.In fact, the machining conditions of metal-based composite materials and titanium alloys have been modeled and optimized to improve machined surface integrity, increase productivity, and improve process accuracy. Subsequently, meet the quality and safety requirements of aeronautical parts.Methods such as Experimental Design, Taguchi and Surface of Response were used for calibration and process control parameters and operating conditions
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Olsen, Peter A. "Shear Modulus Degradation of Liquefying Sand: Quantification and Modeling." BYU ScholarsArchive, 2007. https://scholarsarchive.byu.edu/etd/1214.
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A major concern for geotechnical engineers is the ability to predict how a soil will react to large ground motions produced by earthquakes. Of all the different types of soil, liquefiable soils present some of the greatest challenges. The ability to quantify the degradation of a soil's shear modulus as it undergoes liquefaction would help engineers design more reliably and economically. This thesis uses ground motions recorded by an array of downhole accelerometers on Port Island, Japan, during the 1995 Kobe Earthquake, to quantify the shear modulus of sand as it liquefies. It has been shown that the shear modulus of sand decreases significantly as it liquefies, apparently decreasing in proportion to the increasing excess pore water pressure ratio (Ru). When completely liquefied, the shear modulus of sand (Ru = 1.0) for a relative density of 40 to 50% is approximately 15% of the high-strain modulus of the sand in its non-liquefied state, or 1% of its initial low-strain value. Presented in this thesis is an approach to modeling the shear modulus degradation of sand as it liquefies. This approach, called the "degrading shear modulus backbone curve method" reasonably predicts the hysteretic shear stress behavior of the liquefied sand. The shear stresses and ground accelerations computed using this method reasonably matches those recorded at the Port Island Downhole Array (PIDA) site. The degrading shear modulus backbone method is recommended as a possible method for conducting ground response analyses at sites with potentially liquefiable soils.
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Jakel, Roland. "Linear Dynamic System Analyses with Creo Simulate – Theory & Application Examples, Capabilities, Limitations –." Universitätsbibliothek Chemnitz, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-225992.
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1. Einführung in die Theorie dynamischer Analysen mit Creo Simulate 2. Modalanalysen (Standard und mit Vorspannung) 3. Dynamische Analysen einschließlich Klassifizierung der Analysen; einige einfache Beispiele für eigene Studien (eine Welle unter Unwuchtanregung und ein Ein-Massen-Schwinger) sowie etliche Beispiele größerer dynamischer Systemmodelle aus unterschiedlichsten Anwendungsbereichen 4. Feedback an den Softwareentwickler PTC (Verbesserungsvorschläge und Softwarefehler) 5. Referenzen<br>1. Introduction to dynamic analysis theory in Creo Simulate 2. Modal analysis (standard and with prestress) 3. Dynamic analysis, including analysis classification, some simple examples for own self-studies (shaft under unbalance excitation and a one-mass-oscillator) and several real-world examples of bigger dynamic systems 4. Feedback to the software developer PTC (enhancement requests and code issues) 5. References
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Kunicka, Beata Iwona. "Spacecraft dynamic analysis and correlation with test results : Shock environment analysis of LISA Pathfinder at VESTA test bed." Thesis, Luleå tekniska universitet, Rymdteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-62910.
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The particular study case in this thesis is the shock test performed on the LISA Pathfinder satellite conducted in a laboratory environment on a dedicated test bed: Vega Shock Test Apparatus (VESTA). This test is considered fully representative to study shock levels produced by fairing jettisoning event at Vega Launcher Vehicle, which induces high shock loads towards the satellite. In the frame of this thesis, some transient response analyses have been conducted in MSC Nastran, and a shock simulation tool for the VESTA test configuration has been developed. The simulation tool is based on Nastran Direct Transient Response Analysis solver (SOL 109), and is representative of the upper composite of Vega with the LISA Pathfinder coupled to it. Post-processing routines of transient response signals were conducted in Dynaworks which served to calculate Shock Response Spectra (SRS). The simulation tool is a model of forcing function parameters for transient analysis which adequately correlates with the shock real test data, in order to understand how the effect of shock generated by the launcher is seen in the satellite and its sub-systems. Since available computation resources are limited the parameters for analysis were optimised for computation time, file size, memory capacity, and model complexity. The forcing function represents a release of the HSS clamp band which is responsible for fairing jettisoning, thus the parameters which were studied are mostly concerning the modelling of this event. Among many investigated, those which visibly improved SRS correlation are radial forcing function shape, implementation of axial impulse, clamp band loading geometry and refined loading scheme. Integration time step duration and analysis duration were also studied and found to improve correlation. From each analysis, the qualifying shock environment was then derived by linear scaling in proportion of the applied preload, and considering a qualification margin of 3dB. Consecutive tracking of structural responses along shock propagation path exposed gradual changes in responses pattern and revealed an important property that a breathing mode (n = 0) at the base of a conical Adapter translates into an axial input to the spacecraft. The parametrisation itself was based on responses registered at interfaces located in near-field (where the clamp band is located and forcing function is applied) and medium-field with respect to the shock event location. Following shock propagation path, the final step was the analysis of shock responses inside the satellite located in a far-field region, which still revealed a very good correlation of results. Thus, it can be said that parametrisation process was adequate, and the developed shock simulation tool can be qualified. However, due to the nature of shock, the tool cannot fully replace VESTA laboratory test, but can support shock assessment process and preparation to such test. In the last part of the thesis, the implementation of some finite element model improvements is investigated. Majority of the panels in spacecraft interior exhibited shock over-prediction due to finite element model limitation. Equipment units modelled as lump masses rigidly attached with RBE2 elements to the panel surface are a source of such local over-predictions. Thus, some of the units were remodelled and transient responses were reinvestigated. It was found that remodelling with either solid elements, or lump mass connected to RBE3 element and reinforced by RBE2 element, can significantly improve local transient responses. This conclusion is in line with conclusions found in ECSS Shock Handbook.
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Chen, Lung Wei, and 陳龍威. "A study in Positioning Optimization of Medical Equipments Using Taguchi-Method and Response Surface Methodology (RSM)." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/69079151382247182692.
Full textAbstract:
碩士<br>國立勤益科技大學<br>工業工程與管理系<br>102<br>Robotic arm already has been widely applied in industry, such as transportation, automatic assembly, combination and other highly complex and precise works or dangerous works which are not suitable for manpower. Many large medical centers utilize robotic arms which are operated by manual control and combine the surgical type of robot in the microscopic image display system. However, the motion trajectory has dynamic characteristics of nonlinear coupling during the multiple axes motion of robotic arm which makes uneasy to achieve the requirement of precise positioning. Therefore, the adjustment of controller parameters becomes the very important factor on the precision positioning.
In the manufacturing process, the precision is the essential factor need to be considered during product processing as particularly most critical important in the precision manufacturing of semi-conductors industry. However, accumulated or repetitive errors are existed under the long-term multiple-axes operation of robotic arm which may proceed to affect the precision of robotic arm to have a few errors that can lead to processing failure and result in the poor quality of product. Therefore, it becomes a widely concerning and sustaining explorative issue for how to improve the precision. However, the current way of precision improvement is mostly using the controller and adopts the visual sensor which is added on robotic arm to improve precision while the system cost is increased.
This study used the applying robotic arm to combine with XX-Y positioning platform. Firstly, we used Taguchi-Method to find out the significant affecting variables which can affect the positioning precision of robotic arm; and secondly, conducted the experiments to those key factors by the utilization of response surface experimental design to find out the most optimized parameters of key factors; and then, used the Backpropagation Neural Network (BPN) to execute the verification. Finally, we compared the results between the 3 methods of Taguchi-Method, Response Surface Methodology (RSM), and Backpropagation Neural Network (BPN) and compared the results mutually.
The results of this study indeed has enhanced the improvement of positioning precision and has shown the possible quality enhancement can be achieved by using Taguchi-Method to combine with Response Surface methodology (RSM).
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Muscolino, G., and Alessandro Palmeri. "An earthquake response spectrum method for linear light secondary substructures." 2007. http://hdl.handle.net/10454/611.
Full textAbstract:
Yes<br>Earthquake response spectrum is the most popular tool in the seismic analysis and design of
structures. In the case of combined primary-secondary (P-S) systems, the response of the supporting P
substructure is generally evaluated without considering the S substructure, which in turn is only required
to bear displacements and/or forces imposed by the P substructure (¿cascade¿ approach). In doing so,
however, dynamic interaction between the P and S components is neglected, and the seismic-induced
response of the S substructure may be heavily underestimated or overestimated. In this paper, a novel
CQC (Complete Quadratic Combination) rule is proposed for the seismic response of linear light S
substructures attached to linear P substructures. The proposed technique overcomes the drawbacks of the
cascade approach by including the effects of dynamic interaction and different damping in the
substructures directly in the cross-correlation coefficients. The computational effort is reduced by using
the eigenproperties of the decoupled substructures and only one earthquake response spectrum for a
reference value of the damping ratio.
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Dash, Sweta Swagatika. "Seismic Analysis of High- Rise Building by Response Spectrum Method." Thesis, 2015. http://ethesis.nitrkl.ac.in/7023/2/Seismic_Dash_2015.pdf.
Full textAbstract:
Reinforced Concrete Frames are the most commonly adopted buildings construction practices in India. With growing economy, urbanisation and unavailability of horizontal space increasing cost of land and need for agricultural land, high-rise sprawling structures have become highly preferable in Indian buildings scenario, especially in urban. With high-rise structures, not only the building has to take up gravity loads, but as well as lateral forces. Many important Indian cities fall under high risk seismic zones, hence strengthening of buildings for lateral forces is a prerequisite. In this study the aim is to analyze the response of a high-rise structure to ground motion using Response Spectrum Analysis. Different models, that is, bare frame, brace frame and shear wall frame are considered in Staad Pro. and change in the time period, stiffness, base shear, storey drifts and top-storey deflection of the building is observed and compared.
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Lu, Shao-Tai, and 呂紹台. "Analysis and Verification of Micro-satellite Structure Subjected to Shock Environmental Loading Using Vibration Response Spectrum Method." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/13045472952742676316.
Full textAbstract:
碩士<br>國立成功大學<br>航空太空工程學系碩博士班<br>96<br>The main goal of this thesis is using vibration response spectrum method to predict the resonance response of a single-degree-of-freedom structural system under the base vibration excitation that is induced by external shock environment. Also, with using FEM simulation software “ANSYS”, we could simulate the dynamic response of a PCB structure under vibration load. Then, discussed the diverseness of projection between response spectrum of multi-degree-of-freedom system and vibration response spectrum method of a single-degree-of-freedom system. Moreover, with using free-falling impact tester to generate the same shock environment on PCB structure. We can verify the accuracy of vibration response spectrum method under the shock vibration environment.
Subsequently, with the application of the aforesaid method, the structural analysis of LEAP satellite which made by NCKU can show the acceleration response of main payload in satellite system under launch shock vibration environment. For the sake of reference of future analysis, design and improvement of satellite, the survey of cumulation between the natural frequency and peak value of vibration response method prediction is important.
Herewith the survival rate of satellite and payload can be raised during the launching. Besides, the subsystem and payload damage caused by the improper design of structure can be reduced accordingly.
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RAZA, AAMIR. "SEISMIC ANALYSIS OF CONFINED MASONRY STRUCTURE USING ETABS." Thesis, 2022. http://dspace.dtu.ac.in:8080/jspui/handle/repository/19390.
Full textAbstract:
Buildings are our basic needs. It protect us from rain, sun, theif e.t.c. We spend most of
our time in a building whether it is residential, commercial, institutional, industrial. In
Damage or collapsing of such types of vital structures leads to a lot of risk for human
lives & results in monetary loss. So, the building should be earthquake resistant. One
of the reasons of failure of structure is earthquake. It is found that the reasons behind
these collapses are mostly due to the poor construction practices and substandard
practices involved in the construction of building. As a structural engineer our duty
should be to improve the seismic performance of structure with keeping economy in
mind.
Confined masonry structure is a construction technology/typology in which first wall
are constructed, followed by column and beam. It is similar to RCC and masonry
structure in appearance but different in resisting the earthquake load. Due to the lack of
relevant design and construction standards, confined masonry construction is currently
not practiced in India. However, several initiatives have been launched to promote
confined masonry construction over the last ten years.
This paper presents the seismic analysis of confined masonry structure using ETABS.
Response spectrum method is used for analysis to study the in plane and out of plane
behaviour under earthquake loading in seismic zone v. Effect of wall density and shape
of column on the seismic performance of confined masonry structure has been also
studied. To study the effect of wall density, analysis is done for 110 mm wall, 150mm
wall and 230mm wall. To study the effect of shape of column, rectangular and square
column is used. Performance of confined masonry and RC frame structure has been
also studied. Results are compared on the basis of maximum storey displacement, max
storey drift, base shear, overturning moment, modal mass participation ratio.
With the study it has been observed that by increasing the wall density seismic
performance of confined masonry structure has been increased. In CMS, it has been
observed that max storey displacement and drift was less but overturning moment &
base shear was more as compare to RC frame structure.
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YanHuang, Jiun, and 黃俊諺. "Numerical Analysis and Experiment study of Reduced Mockup Micro-satellite Structure Model Subjected to impulsive Loading Using the Shock Response Spectrum Method." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/63831159990298339804.
Full textAbstract:
碩士<br>國立成功大學<br>航空太空工程學系碩博士班<br>98<br>The main goal of this thesis is using shock response spectrum method that is expanded from the single-degree-of-freedom structural system to predict the response under the base shock excitation induced by external shock environment. The closed-form solutions for the transient structural response of an undamped structural system with SDOF sustain the impact acceleration pulse from five types of waveform(half sine, rectangular, decay triangular, sawtooth, symmetrical triangular) are derived. The largest response describes the shock response spectrum. After that, confer the effect of different drop impact test conditions on the transient structural response of the printed circuit board. And then with using FEM simulation software “ANSYS” and “Ls-Dyna” to simulate the dynamic response of a PCB structure under shock load, and then the response will compared with the transient analysis and the spectrum analysis. Moreover, use free-falling impact tester to generate the same shock environment on PCB structure. We can verify the accuracy of shock response spectrum method under the shock vibration environment.
The transient analysis was using Input-G-method which the acceleration can be directly input to the support screw of PCB assembly as boundary condition and requires building the model of the test vehicle only whereas does not have to consider friction of the guide rod for the drop table and the strike material. The spectrum analysis combine the shock response spectrum to predict the largest response of structure, and the analysis method can be used in Pyroshock, Seismic Shock and launcher flying.
Subsequently, with the application of the aforesaid method, the structural analysis of CKUTEX satellite which made by NCKU can show the effect of main payload and control PCB in satellite system under launcher shock vibration environment. For the sake of reference of future analysis, design and improvement of satellite, Herewith the survival rate of satellite and payload can be raised during the launching. Besides, the subsystem and payload damage caused by the improper design of structure can be reduced accordingly.
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VISHWAKARMA, ADITYA. "ANALYSIS OF SEISMIC SUSCEPTIBILITY OF AN IRREGULARLY PLANNED SETBACK STRUCTURE WITH A SOFT STOREY ON SLOPING TERRAIN AND PLAIN TERRAIN." Thesis, 2023. http://dspace.dtu.ac.in:8080/jspui/handle/repository/19972.
Full textAbstract:
The construction of multi-story setback buildings with soft storey, or open ground floor,
is in high demand and becoming more and more popular. This effort decreases the
setback configuration's vertical stability and the lateral load resisting system's rigidity.
When a building is supported on sloping land, there are several possibilities for short
and long columns inside the same structure. During earthquake shaking, all columns
and floor slabs at every level move horizontally by the same amount, which may result
in structural damage. In this study, an attempt is made to examine the seismic
performance of setback buildings standing on flat ground as well as on a slope, with
soft storey layout. ETABS, a widely used software programme, was used to analyse
simple 3-D frames of SETBACK structures. Using the study findings several graphs
were drawn for like base shear, storey drift, storey stiffness, displacement, rotation
about z axis are developed for both terrains i.e. plain and sloping. To create a technical
expertise two identical structure were examined on both terrains. All the modelled
structures with open ground storey have been analysed using two distinct methods:
equivalent static force technique, response spectrum method. To counteract this soft
storey impact and the severe reactions, mitigation approaches have been implemented,
and the most effective of these mitigation techniques is provided.
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(9708611), Zackery Ray Roberson. "Advances in Gas Chromatography and Vacuum UV Spectroscopy: Applications to Fire Debris Analysis & Drugs of Abuse." Thesis, 2021.
Find full textAbstract:
In forensic chemistry, a quicker and more accurate analysis of a sample is always being pursued. Speedy analyses allow the analyst to provide quick turn-around times and potentially decrease back-logs that are known to be a problem in the field. Accurate analyses are paramount with the futures and lives of the accused potentially on the line. One of the most common methods of analysis in forensic chemistry laboratories is gas chromatography, chosen for the relative speed and efficiency afforded by this method. Two major routes were attempted to further improve on gas chromatography applications in forensic chemistry.<br> The first route was to decrease separation times for analysis of ignitable liquid residues by using micro-bore wall coated open-tubular columns. Micro-bore columns are much shorter and have higher separation efficiencies than the standard columns used in forensic chemistry, allowing for faster analysis times while maintaining the expected peak separation. Typical separation times for fire debris samples are between thirty minutes and one hour, the micro-bore columns were able to achieve equivalent performance in three minutes. The reduction in analysis time was demonstrated by analysis of ignitable liquid residues from simulated fire debris exemplars.<br> The second route looked at a relatively new detector for gas chromatography known as a vacuum ultraviolet (VUV) spectrophotometer. The VUV detector uses traditional UV and far-ultraviolet light to probe the pi and sigma bonds of the gas phase analytes as well as Rydberg traditions to produce spectra that are nearly unique to a compound. Thus far, the only spectra that were not discernable were from enantiomers, otherwise even diastereomers have been differentiated. The specificity attained with the VUV detector has achieved differentiation of compounds that mass spectrometry, the most common detection method for chromatography in forensic chemistry labs, has difficulty distinguishing. This specificity has been demonstrated herein by analyzing various classes of drugs of abuse and applicability to “real world” samples has been demonstrated by analysis of de-identified seized samples.<br>