Dissertations / Theses on the topic 'Stress analysi'
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CAPPELLO, Riccardo. "Progressi sperimentali e numerici nella valutazione dell'integrita strutturale dei solidi mediante Thermoelastic Stress Analysis." Doctoral thesis, Università degli Studi di Palermo, 2023. https://hdl.handle.net/10447/580150.
Full textCavalli, N. "INFLUENCE OF IMPLANT NUMBER, IMPLANT LENGTH AND CROWN HEIGHT ON BONE STRESS DISTRIBUTION FOR THREE-UNIT BRIDGES IN THE POSTERIOR MANDIBLE: A 3D FINITE ELEMENT ANALYSIS." Doctoral thesis, Università degli Studi di Milano, 2015. http://hdl.handle.net/2434/333063.
Full textBRUNZINI, Agnese. "Effectiveness analysis of traditional and mixed reality simulations in medical training: a methodological approach for the assessment of stress, cognitive load and performance." Doctoral thesis, Università Politecnica delle Marche, 2021. http://hdl.handle.net/11566/287675.
Full textSimulation in medical education is considered a training method capable of improving clinical competence and practitioners’ behaviour, and, consequently quality of care and patient’s outcome. Moreover, the use of new technologies, such as augmented reality, offers to the learners the opportunity to engage themselves in an immersive environment. The opportunity to experiment with this innovative instructional method is effective not only in reducing the risk of errors and wrong approaches but also in experiencing anxiety and stress as in real practice. The challenge is to find the right stress balance: learners have to feel as if they were practicing in the real stressful clinical case, and, at the same time, post-traumatic stress disorders, verifiable especially in the emergency field, must be controlled and avoided. Moreover, it is fundamental also to obtain high performance and learning, thus avoiding cognitive overloads. However, extensive researches about the impact of medical simulations on students’ stress, frustration, cognitive load, and learning are still lacking. For this reason, the main objective of this study is to assess simulation training effectiveness by analysing performance, anxiety, stress, and cognitive load during traditional (with manikin) and advanced (with augmented reality) clinical simulations. A structured and comprehensive methodological approach to assess performance, emotional and cognitive conditions of students has been developed. It includes the acquisition and analysis of psychological parameters (subjective assessment), biometric signals (objective assessment), and task performance. This investigation allows to point out simulations’ weaknesses and offers the opportunity to define useful optimisation guidelines. The methodology has been applied to three case studies: the first one refers to high-fidelity simulations, for the patient management in the emergency room, the second one refers to low-fidelity simulation for rachicentesis. For the third case study, a prototype of a mixed reality simulator for the rachicentesis practice has been designed and developed aiming at improving the sense of realism and immersion of the low-fidelity simulation. While 148 students have been enrolled in the first two case studies, only 36 students have taken part in the pilot study about mixed reality simulation. Descriptive analysis about performance, cognitive and emotional states have been done in all the case studies. For the high-fidelity and low-fidelity simulations, the statistical regression analysis has pointed out which variables affect students’ performance, stress, and cognitive load. For the pilot study about mixed reality, the user experience analysis highlighted the technical limitations of the new technology.
Tufail, Muhammad Aammar. "Use of plant growth promoting endophytic bacteria to alleviate the effects of individual and combined abiotic stresses on plants as an innovative approach to discover new delivery strategies for bacterial bio-stimulants." Doctoral thesis, Università degli studi di Trento, 2021. http://hdl.handle.net/11572/305571.
Full textSathon, Nuttaphon. "Damage and stress analysis on pipework using thermoelastic stress analysis." Thesis, University of Southampton, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427400.
Full textRobinson, Andrew Ferrand. "Assessment of residual stress using thermoelastic stress analysis." Thesis, University of Southampton, 2011. https://eprints.soton.ac.uk/317719/.
Full textGundeboina, Saidulu. "Finite Element Analysis of a Washing Machine Cylinder." Thesis, Högskolan i Skövde, Institutionen för teknik och samhälle, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-4863.
Full textEchard, Benjamin. "Assessment by kriging of the reliability of structures subjected to fatigue stress." Thesis, Clermont-Ferrand 2, 2012. http://www.theses.fr/2012CLF22269/document.
Full textTraditional procedures for designing structures against fatigue are grounded upon the use of so-called safety factors in an attempt to ensure structural integrity while masking the uncertainties inherent to fatigue. These engineering methods are simple to use and fortunately, they give satisfactory solutions with regard to safety. However, they do not provide the designer with the structure’s safety margin as well as the influence of each design parameter on reliability. Probabilistic approaches are considered in this thesis in order to acquire this information, which is essential for an optimal design against fatigue. A general approach for probabilistic analysis in fatigue is proposed in this manuscript. It relies on the modelling of the uncertainties (load, material properties, geometry, and fatigue curve), and aims at assessing the reliability level of the studied structure in the case of a fatigue failure scenario. Classical reliability methods require a large number of calls to the mechanical model of the structure and are thus not applicable when the model evaluation is time-demanding. A family of methods named AK-RM (Active learning and Kriging-based Reliability methods) is proposed in this research work in order to solve the reliability problem with a minimum number of mechanical model evaluations. The general approach is applied to two case studies submitted by SNECMA in the frame of the ANR project APPRoFi
Hilley, David B. "Temporal streams programming abstractions for distributed live stream analysis applications /." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31695.
Full textCommittee Chair: Ramachandran, Umakishore; Committee Member: Clark, Nathan; Committee Member: Haskin, Roger; Committee Member: Pu, Calton; Committee Member: Rehg, James. Part of the SMARTech Electronic Thesis and Dissertation Collection.
Chen, Hanjie. "Stress analysis in longwall entry roof under high horizontal stress." Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=550.
Full textTitle from document title page. Document formatted into pages; contains xvii, 278 p. : ill. (some col.), maps. Vita. Includes abstract. Includes bibliographical references (p. 274-277).
Sime, Anthony P. "Stress analysis of overlapped crankshafts." Thesis, University of Nottingham, 1998. http://eprints.nottingham.ac.uk/11566/.
Full textLiu, Shulong. "Stress analysis of composite laminates." Thesis, University of Nottingham, 2001. http://eprints.nottingham.ac.uk/13176/.
Full textZhao, Youhao. "Stress-Function Variational Method for Stress Analysis of Adhesively Bonded Joints." Thesis, North Dakota State University, 2014. https://hdl.handle.net/10365/27271.
Full textNSF; ND NASA EPSCoR; Faculty Research Initiative Grant; Department of Mechanical Engineering at NDSU.
Persson, Leif. "Quasi-radial solutions of the p-harmonic equation in the plane and their stream functions." Licentiate thesis, Luleå tekniska universitet, 1988. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-25699.
Full textLévy, Elise. "Maladies neurodégénératives et stress oxydant." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASB028.
Full textAlzheimer's disease and prion diseases are incurable neurodegenerative diseases associated with the transconformation of a polypeptide: the Aß peptide and the prion protein (PrP) respectively. These misfolded polypeptides then form different aggregates in the brain, leading to neuronal death. In a healthy individual, PrP has a neuroprotective function, but in patients suffering from Alzheimer or prion diseases, the toxicity of some pathological aggregates is mediated by this protein. Moreover, both pathologies are associated with an early chronic oxidative stress, that is toxic. It can promote and be promoted by protein aggregation, without the aggregates involved in this vicious circle being precisely identified.To study oxidative stress in these diseases, I developed innovative cellular models to monitor oxidation markers in real time, and bioinformatic tools to analyze the results. My work shows that the unique expression of the healthy form of Aß or PrP protects cells from an exogenous oxidant. However, the addition to the culture medium of the same cells of recombinant Aß and PrP promotes the appearance of oxidative stress, only for cells expressing normal PrP. This effect is visible for A in the form of amyloid fibrils, and for PrP in the form of monomer, oligomers and potentially amyloid fibrils. This work thus validates the central role of normal PrP in physiology and pathology. My results could suggest a role of glutathione peroxidases in mediating the protective effect of normal PrP, and an activation of NADPH oxidases via PrP in the presence of pathological aggregates
Macgregor, Kenneth Waddell. "An investigation into the induced state of stress around inclined boreholes under non-hydrostatic stress conditions." Thesis, University of Strathclyde, 1987. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21493.
Full textAdnan, Md Asif, and Ahmed Shehata. "Stress Analysis Validation for Gear Design." Thesis, Blekinge Tekniska Högskola, Institutionen för maskinteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-16862.
Full textLi, Henan. "Flexible Pipe Stress and Fatigue Analysis." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for marin teknikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18646.
Full textChodeshwar, Korsa Veera Bhadraiah Dora Bharadwaj. "Stress Analysis of Bogie Frame Structure." Thesis, Blekinge Tekniska Högskola, Institutionen för maskinteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-16043.
Full textNowak, William J. "Fatigue stress analysis of turbine blades /." Online version of thesis, 2007. http://hdl.handle.net/1850/5467.
Full textSalihu, B. M. "Stress analysis of drillstring threaded connections." Thesis, Cranfield University, 2011. http://dspace.lib.cranfield.ac.uk/handle/1826/7752.
Full textRamanauskaitė, Giedrė. "Stress testing in credit risk analysis." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2008. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2008~D_20080620_110415-38466.
Full textKredito įstaigų priežiūros institucijos nepateikia komerciniams bankams kokius metodus jie turėtų naudoti testavime nepalankiomis sąlygomis. Tiriamasis darbas buvo atliktas tuo tikslu, kad būtų išsiaiškinta kokie matematiniai ir statistiniai metodai yra ir gali būti naudojami kredito rizikos vertinime testuojant nepalankiomis sąlygomis. Kredito rizika yra viena iš didžiausių finansinių rizikų su kuria bankai susiduria. Testavimas nepalankiomis sąlygomis yra kredito rizikos vertinimo įrankis, padedantis nustatyti įvykių, kurių realizavimosi tikimybės yra mažos, tačiau jiems įvykus, bankai patirtų reikšmingus nuostolius, pasekmes. Šis tyrimas nustatė, jog labiausiai tikėtinas įvykis gali būti ypatingai nepalankios ekonominės sąlygos. Dėl šios priežasties darbe yra pristatyti metodai, kurie įvertina makroekonominių veiksnių įtaką. Vektorinė autoregresija ir vektorinis paklaidų korekcijos modelis buvo patikrinti naudojant Švedijos centrinio banko, Švedijos statistikos departamento ir Eurostat empirinius duomenis. Finansinio stabilumo įvertinimui vertėtų naudoti vektorinį autoregresijos ar vektorinį paklaidų korekcijos modelius, nes šie modeliai geriausiai aprašo ekonominę aplinką bei yra labai tinkami šokų analizei, kadangi įvertina bet kurio veiksnio įtaką visai sistemai. Struktūra: įvadas, pagrindinė dalis (kredito rizika, metodai ir empirinė analizė), publikacija, išvados, literatūros sąrašas. Tiriamasis darbas sudarytas iš: 50 psl. teksto be priedų, 13 paveikslų, 11... [toliau žr. visą tekstą]
Lotfi, Majid. "Stress analysis of oil lubricated bearings." Thesis, University of Canterbury. Mechanical Engineering, 1988. http://hdl.handle.net/10092/6040.
Full textMcDonald, Eric S. "Optimization techniques for contact stress analysis." Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/23999.
Full textZiada, Hassan M. A/R. "Photoelastic stress analysis in bonded bridges." Thesis, Queen's University Belfast, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334493.
Full textBridgett, Stephen John. "Detail suppression of stress analysis models." Thesis, Queen's University Belfast, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387980.
Full textDonaghy, Richard James. "Dimensional reduction of stress analysis models." Thesis, Queen's University Belfast, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263368.
Full textO'Neill, J. M. "Thermoelastic stress analysis of anisotropic materials." Thesis, University of Nottingham, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376642.
Full textFulton, Matthew Charles. "Advanced topics in thermoelastic stress analysis." Thesis, University of Liverpool, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.397388.
Full textWimpory, Robert Charles. "Aspects of neutron residual stress analysis." Thesis, Loughborough University, 1999. https://dspace.lboro.ac.uk/2134/25162.
Full textPolzer, Stanislav. "Stress-Strain Analysis of Aortic Aneurysms." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-234135.
Full textYi, Jun 1959. "Stress compatible bimaterial interface elements with application to transient dynamic stress analysis." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22842.
Full textThis thesis formulates and implements new finite elements for obtaining the correct values of the stress components, both continuous and discontinuous ones, at bimaterial interface points under general dynamic loading, assuming linear, isotropic, elastic material behaviour.
The constructed finite elements programs, suitable for analyzing two-dimensional and axisymmetric three-dimensional problems, have been validated by comparing the predicted responses with the exact analytical solutions of some non-trivial impact loading (wave-propagation) problems.
The work provides a necessary tool for analyzing and designing composite structures, for example prosthetic knee and hip joints in the biomechanics field.
Vandenbussche, Pierre. "Otolithes et bioindication : conséquence d’un stress environnemental sur la morphologie des sagittae de Dicentrarchus labrax et Oblada melanura." Thesis, Université Côte d'Azur (ComUE), 2017. http://www.theses.fr/2017AZUR4122/document.
Full textThe aim of our study was to validate the most suitable environmental indicator among three approaches: morphological measurements of fish juveniles; quantification of the fluctuating asymmetry of their otoliths; analysis of their otolith shape. In aquaria, results for Dicentrarchus labrax have shown that mono-contamination by classical pollutants, such as phosphorus or zinc, has no effect for concentrations corresponding to those measured in highly anthropized environments. Nevertheless, higher zinc concentrations induce otolith shape alterations in addition to their negative impact on fish size and weight. On the basis of our three-year in situ Oblada melanura samplings, we have demonstrated that, in a replicable manner, compared to preserved areas and small waterway mouths, mid-size recreational harbours negatively impact juvenile standard length and also alter otolith shape. By comparison with in aquaria results, these alterations are consistent with a synergy of disturbance sources which taken independently do not have any impact. Taking into account all our results, we deduce that size and weight are easy to measure but show response variability. Measurement of fish juvenile otoliths' fluctuating asymmetry does not seem to be suitable for use in bioindication. Conversely, fish juvenile sagittae shape analysis is well-suited to surveys of environmental modifications, for fishes from two different families, Moronidae and Sparidae. This analysis seems to be a promising tool for bioindication, with a practical application for environmental managers
Austin, Tara Ashley. "Stress and Anxiety Interventions for Classical Musicians." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/7248.
Full textTouzy, Gaëtan. "Analyse génétique et écophysiologique de la tolérance à la sècheresse et au stress thermique chez le blé tendre (T. Aestivum L.)." Thesis, Université Clermont Auvergne (2017-2020), 2019. http://www.theses.fr/2019CLFAC011.
Full textIn a context of climate change, the characterization of wheat varieties in response to drought and heat stress events is one of the major challenges of agriculture. This PhD thesis, resulting from a private-public partnership between Arvalis ‘Institut du Végétal’, Biogemma and INRA (“Institut National de la Recherche Agronomique”), aimed at providing necessary knowledge and tools to identify drought or heat-tolerant varieties and breed for varieties that meet these requirements. Analyses were conducted using a panel of 220 commercial varieties, genotyped with 280K SNP and tested in 35 environments (combination of year, location and water regime) and an experiment under controlled conditions where heat stress was applied during grain filling. The complexity of the study of drought and heat tolerance led us to present this thesis by first separating hydric and thermal stresses, and then to explore a multi-stress analysis method. Even if breeding has improved the performance of varieties under optimal water conditions, we showed that genetic progress must be accelerated and better distributed according to different stress scenarios. We propose several genetic determinants that could allow genetic gain in stressful environments. Our results and methods are discussed in view of the needs for varietal recommendation and improvement. Additional research strategies and methods improvements were also suggested
Lundholm, Beatrice. "Analysis of rock stress and rock stress measurements with application to Äspö HRL." Licentiate thesis, Luleå tekniska universitet, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26623.
Full textGodkänd; 2000; 20070316 (ysko)
Schepers, Scott Timothy. "Renewal In The Context Of Stress: A Potential Mechanism Of Stress-Induced Reinstatement." ScholarWorks @ UVM, 2017. http://scholarworks.uvm.edu/graddis/780.
Full textANNICCHIARICO, CLAUDIO. "Stress analysis of a CVT belt transmission." Doctoral thesis, 2009. http://hdl.handle.net/2158/590115.
Full textFasani, Elisa. "Identification of regulatory elements responsible for metal hyperaccumulation in the Brassicaceae family. Functional analysis of the Arabidopsis thaliana MYB48 and MYB59 transcription factors." Doctoral thesis, 2014. http://hdl.handle.net/11562/671558.
Full textChapter 1: Identification of regulatory elements responsible for metal hyperaccumulation in the Brassicaceae family. The role of the metal transporter MTP1 in metal tolerance and accumulation has been extensively studied, due also to its great importance in the hypertolerance trait. MTP1 is known to have undergone copy number expansion in hyperaccumulator Arabidopsis halleri; moreover, possible differences in cis-regulation between hyperaccumulators and non-accumulators have been proposed. This work focuses on the analysis of the MTP1 promoter. The expression pattern and levels driven by the Arabidopsis thaliana and A. halleri promoter sequences are markedly different, coherently with the different accumulation ability and metal storage tissues displayed by the two species. MTP1 expression in roots was found in both species and is associated with the presence of root-specific cis elements in both promoters. Similarly, guard cell-specific expression was observed for both A. thaliana and A. halleri sequences and is associated with the presence of Dof-binding sites. In addition, the MTP1 promoter of A. halleri drives expression in trichomes. This interesting localization is likely associated to a couple of MYB-binding sites in the 5’UTR of the gene. Metal accumulation in trichomes is an intriguing feature in A. halleri and is possibly involved in short-term tolerance to metals. Chapter 2: Functional analysis of the Arabidopsis thaliana MYB48 and MYB59 transcription factors. MYB transcription factors are involved in many events of plant life, as cell differentiation and metabolism, plant development, response to hormones and to environmental stimuli. Among the others, MYB48 and MYB59 have been proposed to participate in secondary development, cell cycle regulation and response to abiotic stress in Arabidopsis thaliana. In this work, a myb48myb59 double mutant was used due to probable functional redundancy of the two transcription factors. myb48myb59 plants show smaller rosette leaves, likely due to reduced cell distension, delayed flowering and longer roots in comparison to wt; early senescence was also considered and confirmed by the higher SAG12 expression levels. The phenotype is consistent with a reduced cytokinin content: this observation was confirmed by the increased sensitivity to exogenous cytokinins and by the modulated genes resulting from the microarray experiment.
WANG, MAO-SHENG, and 王茂昇. "Residual Stress Analysis for an Aluminum Plate using Thermoelastic Stress Analysis." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/86201578873244040926.
Full text國立高雄應用科技大學
模具工程系
104
Thermoelastic stress analysis (TSA) employs infrared to record the thermoelastic response of the stressed materials and provides full-field stress information over a surface. Theoretically, the thermorelastic response of a loaded member is resulting from the thermoelastic effect and that is as a material experiences mechanical excitation, the material will get cooler in tension or warmer in compression. The temperature variation due to the thermoelastic behavior is very small and it even approximately attains the order of 10-3. Contemporarily, the TSA equipment is able to rapidly capture the tiny temperature change over the stressed surface and correlate it to the change in the sum of principal stresses or isopachic stress due to arrayed infrared detectors applied. The traditional TSA theory indicated that for a plane-stressed elastic body under adiabatic and reversible conditions, the rate of temperature disturbance of a dynamically loaded member is linearly proportional to the stress amplitude and this proportionality is defined to be thermoelastic constant. However, recent studies discovered that the thermal response given by a loaded member is not only a function of stress amplitude, but also the mean stress. Therefore, the thermoelastic coefficient is then revised and expressed as stress dependence but not a constant. Moreover, according to the mechanics aspect, the mean stress represents a static component of stress. Residual stress can be essentially regarded to as the mean stress. Hence, one is able to detect the residual stress by using TSA technique. This work attempts utilizing TSA technique to investigate the residual stress for the 2024 aluminum alloy plate.
GUALANO, Stefania. "Defining optimal Hyperspectral Narrowbands as proximal sensing in the early detection of Xylella fastidiosa in olive trees." Doctoral thesis, 2017. http://hdl.handle.net/11589/99599.
Full textThe occurrence of the Olive Quick Decline Syndrome (OQDS) caused by Xylella fastidiosa (Xf) in Apulia region (Italy), with the strain Co.Di.RO (Complesso del Disseccamento Rapido dell’Olivo) affecting mainly the olive trees, poses a serious threat for olive production in all Mediterranean countries. Xf is a regulated pathogen in Europe (EPPO A1 list) because it affects more than 350 plant species worldwide. Infected olive trees may die as a consequence of the multiplication of the bacterium inside the vascular system which restricts the water flow from the roots to the canopy of the tree. Around 95% of olive cultivation is concentrated in the Mediterranean region and Italy ranks second worldwide. Accordingly, Xf represents the main threat of olive trees worldwide due to the severe symptoms induced (mainly leaf scorch, dieback and quick decline of the tree), the long list of sap-feeding insects which may efficiently spread the pathogen, as the Philaenous spumarius in Apulia, and the large number of secondary hosts. Xf restricts the cultivation of olive trees and the preservation of the historical heritage of olive trees in the Mediterranean region. Currently, no control measures are fully effective in the control of the bacterium and in the management of the olive quick decline; therefore the early detection of infected trees, their immediate eradication and vector control strategies are the only means of avoiding or containing the risk of contamination. These measures could be more effective if the infection is identified at early stages of disease development, in order to mitigate the spread of the pathogen and infections to neighbouring trees. However, visual inspections in the field are time-consuming and expensive. To this aim, remote sensing could be a useful tool to detect water stress induced by Xf infection in olive trees at early stages. Recently, an increase in research occurred in the application of Geomatic techniques, due to a greater availability of Remote and Proximal Sensing (RS, PS) instruments which has led to significant progress in the monitoring of complex biological phenomena and relative data management for running in, stand-alone, or web-based Geographic Information System (GIS) platforms. In this way it is possible to integrate heterogeneous spatial data in a single operative environment. Such data can be obtained by means of direct methods or indirect methods. The resulting data can be used for the implementation of provisional models to identify a plant adversity in order to rationalize the intervention strategy. The first research of this work, the suitability of photointerpretation techniques to recognize and classify the plants damaged by OQDS in GIS environment was evaluated, for this purpose very high geometrical resolution aerial images were used by processing visible (VIS) and near infrared (NIR) data on a study area in South of Apulia region, which represents the first outbreak area of Xf. The remotely acquired radiometric measurements were aimed at identifying appropriate photo-types, morphologically suitable in detecting the alteration of olive trees associated to different levels of OQDS-like symptoms. The use of spatially defined images strengthened by the presence of the near infrared band has greatly facilitated the identification of signs of OQDS starting with key photo types which are well correlated to the expression of the disease. The technique made it possible to identify 20% of the photo interpreted OQDS-trees and infected by Xf. This achievement is the prerequisite to thoroughly examine and improve the methodology through the use of stereoscopic restitution in the GIS environment. However, a second research was aimed at assessing the potential of hyperspectral reflectance data (HR) to identify the infection of Xf in olive at early stages of development. Sampling was carried out on infected plants belonging to the two main olive varieties varieties (cvs. “Cellina di Nardò” and “Leccino”) grown in a commercial grove located in the outbreak area of Xf in south Apulia. Each sample was made of leaves collected from 10 twigs/tree with different levels of infection. The study focused on the: (i) the discrimination between infected asymptomatic and non infected leaves; (ii) the selection of the best wavelengths for highlighting this discrimination and (iii) the identification of bio-physiological indicators (vegetation indices) correlated to the OQDS induced by Xf. The discrimination of infected leaves has been made using pre-elaborated data acquired with a field spectroradiometer, in the spectral wavelengths range between 400 and 1830 nm. A heuristic approach to variable selection, used in literature (Lambda-Lambda R2 model - LLR2, Principal Component Analisys model - PCA and Wilks' Lambda) and a combined general purpose detection method, proposed in this research, named interval PCA Internal Clustering Validation, iPCA-ICV have been compared. The unsupervised method proposed, divides the spectrum of reflectance data into a determined number of intervals, calculates the PCA within them (iPCA) and validates the goodness of the groupings obtained (classes) through Cluster Validity index measurement. The discriminative ability of selected wavelengths by the two methods was assessed by generalized discriminant analysis based on canonical correlation and measurement of error type such as leave-one-out cross-validation, through confusion matrices. From both methods it was possible to discriminate leaves infected by Xf and to select specific narrowbands. However, the best discriminative power was obtained from iPCA-ICV for both varieties (error rates of 23.7% and of 22.02% respectively for cv. Cellina di Nardò and cv. Leccino), compared to the reference method (error rates equivalent to 42.47% and 22.02% respectively for cv. Cellina di Nardò and cv. Leccino). The two methods have shown differences in number and in the position in the narrowbands selected (each of 10 nm) between the two varieties. In particular, both agree with the VIS regions (close to the blue and the red) and that of Short Wave Infrared (SWIR) as portions of the spectrum increase the discrimination of Leccino, the variety less affected by the infection (23.1%), while, for Cellina, the species more affected (85.7% of positive findings). The iPCA-ICV identifies the absorption bands of water around 1180 and 1400 nm (and many bands of SWIR). The heuristic method identifies two bands of 705 and 805 nm, as determinants in the identification of Xylella. The identification of critical regions of the spectrum, therefore, is the first logical step towards the development of indicators of robust stress based on hyperspectral images. The band selection techniques, also, are extremely useful not only to improve the power of predictive models, but also for the interpretation of the data or design of specific sensors for Pest Disease Detection (PDD).
Chang, Junwei, and 張峻維. "Paving Block Stress Analysis." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/86865802885219075047.
Full text國立高雄大學
土木與環境工程學系碩士班
102
In the present study, the traditional paving blocks used for pedestrian path as well as the innovated paving blocks specially designed for vehicle roads are evaluated in details. The influence of road roughness on the stress concentration induced by a tire-brick dynamic impact is emphasized. Results are compared with those obtained by field tests and numerical simulations. The embedded water channels are proposed for improvements in drainage performance in the blocks subject to the heavy duty vehicle load. Experiments show that the blocks with the embedded water channels meet the regulatory standards of the permeable ability. The soft sensor sheet is employed in the real paving block traffic lane field tests to measure the contact pressure between tire and blocks, between blocks, and also between blocks and the ground. The relative elevation of the target block is one of the major study parameters. The corresponding influences on the impact pressure are evaluated in field tests and numerical simulations. A finite element tire model consisting of masses, suspension spring, a rigid rim, and half rubber tire skin simulated by three portions of membranes filled with constant inner air pressure is appropriately developed for the numerical simulation. The tire-road contact, the tire inner pressure, and the dynamic forces due to inertia are considered as the major loads. The tire-road contact impact and the stress concentration of the embedded water channels are illustrated in the numerical block models. The results are in good agreement with those obtained from the field test. The present study shows that the magnitude and the distribution pattern are sensitive to the roughness of the road surface. The stress concentrations are found to be along the block edges on the loading face and inside the water channels. There is no significant difference between the peak values of the stresses along the edges and channels if the ground is smooth. The edges contact pressure induced by the dynamic impact due to a bumpy ground could be more than 10 times higher than that induced by a smooth run-over. The stresses in water channels are relatively not so sensitive to the elevation of the target block. This thesis serves as a preliminary study to the new designed paving block. There are still broad researches and applications in the future.
Chou, Yung-Cheng, and 周蛹城. "Residual Stress Measurement using Non-contacting Thermoelastic Stress Analysis." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/92437433978827920076.
Full text國立高雄應用科技大學
模具工程系碩士班
102
Thermoelastic stress analysis (TSA) is a nondestructive and non-contacting experimental technique, which exploits thermoelastic response of materials to provide full-field stress information over a surface. Fundamental thermorelastic theory is based on the thermoelastic effect and that is as a material experiences mechanical excitation, the material gets cooler in tension or warmer in compression. Temperature variation due to thermoelastic behavior can be very small and even approximately attain the order of 10-3. TSA technique utilizes infrared detectors to capture the tiny temperature change on the stressed surface and correlate it to the change in the sum of normal stresses or isopachic stress. Traditionally, theoretical thermoelasticity indicated that for an elastic body under adiabatic and reversible conditions, the rate of temperature disturbance of a dynamically loaded member is linearly proportional to the stress amplitude and the proportionality is defined to be thermoelastic constant. However, recent thermoelastic studies discovered that the thermal response is not only a function of stress amplitude, but mean stress which represents a static component of stress. This work will introduce TSA technique and investigate its applicability on measuring residual stress in a metallic material.
Huang, Ren-Yu, and 黃仁育. "Stress Analysis of Thin Type lectronic Packagesand Patent Analysis For Die Stress Improvement." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/65485513297917967050.
Full text國立雲林科技大學
機械工程系碩士班
94
Due to the CTE (coefficient of thermal expansion) mismatch among different materials of the package , the warpage and thermal stresses of the package are induced by temperature variations . In the present work , the finite element method (FEM) is used to simulate the package warpage and component stresses of TSOP(Thin Small Outline Package) during the manufacturing processes . The accuracy of the package model is verified by comparing the simulated package warpage with the warpage measurement by profilometer .The effect of various through holes in the die pad on the die stresses during the reflow process , the largest temperature variation of all processes , is discussed . The results show that the effect of through holes in the die pad on die stresses is more significant with the smaller die size . Also, the patent information of die stress improvement for leadframe type packages are studied to depict the patent map and summarize the technology development and market trend of die stress improvement. The investigated patent information can provide guidelines to check possible patent right violation of new design and on-line product to avoid useless spending in package research and development. It can be referred by industry to improve die stress , upgrade package technology and enhance package reliability.
FREZZINI, MARIA AGOSTINA. "Investigation of the contribution of emission sources to atmospheric particulate matter concentration (PM) and to its redox properties." Doctoral thesis, 2022. http://hdl.handle.net/11573/1637945.
Full textLiu, Kun-I., and 劉坤一. "Transient Thermal Stress and Residual Stress analysis in Plate Welding." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/18338594692718581054.
Full textLiu, Kun-Yi, and 劉坤一. "ransient thermal stress and residual stress analysis in plate welding." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/03654790707247342621.
Full textLee, Pei-Sheng, and 李沛生. "Verification of Implant Stress Analysis." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/d8ktxq.
Full text國立臺灣科技大學
機械工程系
95
In order to increase the probability of successful oral implantation computer simulation can be employed to analyze the loading situation of the alveolus bone after implantation. Finite Element Method is the most important computer software used to analyze the stress distribution over the alveolus under occlusion. However, during the FEM analysis, many conditions are simplified, the outcome of the analysis is needed to be verified by some experimental works. In this thesis, the alveolus bone was approached as a two-material model. The simulation model was fabricated by using various compositions of quartz powder and resin. The material constants (Modulus of Elasticity and Poisson’s Ration) of the model were determined experimentally. An implant was put in the model as well as an abutment and a crown to simulate a real oral implantation. The complete model under occlusion was simulated by FEM. At the surface of the real model which had maximum stress was bonded a bi-axes strain gage. After the experiment, the measured strains were found agree well with those results from FEM.
李惠娥. "Application of stress analysis on." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/15725506937143561916.
Full text林宗澍. "Stress Analysis of Flexible Packages." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/63416459219295187740.
Full text中華大學
機械與航太工程研究所
94
Nonlinear finite element method was employed in the study to analyze the deformation and stress distribution of a new type of flexible flip chip packages under service conditions. Four procedures were simulated in the finite element analysis. Firstly, the package was attached on a surface by a rigid concave mask with a curvature radius of 30 mm. Secondly, the contact condition of the upper surface was relieved to simulate the removing of the compressive force. Thirdly, the temperature of environment was cooled down to -55℃. Finally, the temperature of environment was raised to 125℃. Three different materials of the bump core were considered in the numerical analysis to study the material effect on the stress behavior. Furthermore, the D. O. E. method were used to study the influence of the bump polymer core width, the bump sidewall thickness and the bump core material on the stress distribution. The analysis results show that higher Young’s modulus will induce the lower stress during the step 1 and 2, but higher Young’s modulus and lower CTE will induce higher stress level during TCT (Thermal cycle test) process.