140 research outputs found

    Estimation of the dissipative heat sources related to the total energy input of a cfrp composite by using the second amplitude harmonic of the thermal signal

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    Theories for predicting the fatigue behaviour of composite laminates often make strong assumptions on the damage mechanisms that strongly depend on the designed laminate lay-up. In this regard, several physical and empirical models were proposed in the literature that generally require experimental validations. The experimental techniques, such as thermography, also provide useful tools for monitoring the behaviour of the specific material so, that they can be used to support the study of the damage mechanisms of materials. In this research, the second amplitude harmonic of the thermal signal has been investigated and used to assess the relationship with the total energy input in order to estimate the fatigue strength of the material. A thermal index was assessed by monitoring the constant amplitude tests (S/N curve) that were performed on a quasi-isotropic carbon fibre reinforced polymer (CFRP) laminate obtained by the automated fibre placement process. The obtained results demonstrated the capability of the second amplitude harmonic of the thermal signal to describe and monitor the fatigue damage

    Pengaruh Kualitas Produk, Harga Dan Citra Merek Terhadap Keputusan Pembelian Produk PT. Mustika Ratubuana Internasional Tbk.

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    The decision to purchase some products for beauty that made by women in generally is a reasonable thing to do. Similarly, purchasing decisions of products PT . Mustika Ratubuana International Tbk , which is done by the student Fisip Diponegoro University . Thus , this study will focus on the results that show about the product purchasing decisions PT . Mustika Ratubuana International Tbk that taken by the respondentThe purpose of this study was to determine the presence or absence of the influence of product quality, price and brand image on product purchasing decisions PT . Mustika Ratubuana International Tbk . The case study at the student of Fisip University Diponegoro . The type of this research is explanatory research . Mechanical sampling using non probability sampling which accidental sampling method and purposive sampling . The number of samples taken by 100 respondents . in this research used SPSS version 21.0.Based on the results of the descriptive analysis of 49% indicates that the variable quality of the products included in the category quite well . 44 % indicates that the variable price included in the category of price , 48 % showing that the brand image variables included in both categories. Based on the calculation of the correlation coefficient and the coefficient of determination shows that the purchasing decision can be explained by 82.7 % by the variable quality of product , price and brand image while the rest of 17,3 explained by other factors . Based on the calculation of F test shows that there is influence between product quality , price and brand image to the purchasing decision .The Suggestions in this research is to improve product quality in both the packaging and the benefits of the product . Moreover in terms of price , the price of conformity with quality products must also be upgraded and improved

    Study of the plastic behavior around the crack tip by means of thermal methods

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    AbstractIn this work, the behaviour of two cracked stainless steel AISI 410 and C3FM was studied by means of a new procedure based on thermographic methods. A temperature model in time domain was considered in order to obtain information about the first and the second order harmonic of the temperature signal. Interesting results were obtained in term of possibility to describe the plastic phenomena at the crack tip

    Influence of Second-Order Effects on Thermoelastic Behaviour in the Proximity of Crack Tips on Titanium

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    The Stress Intensity Factor (SIF) is used to describe the stress state and the mechanical behaviour of a material in the presence of cracks. SIF can be experimentally assessed using contactless techniques such as Thermoelastic Stress Analysis (TSA). The classic TSA theory concerns the relationship between temperature and stress variations and was successfully applied to fracture mechanics for SIF evaluation and crack tip location. This theory is no longer valid for some materials, such as titanium and aluminium, where the temperature variations also depend on the mean stress. The objective of this work was to present a new thermoelastic equation that includes the mean stress dependence to investigate the thermoelastic effect in the proximity of crack tips on titanium. Westergaard’s equations and Williams’s series expansion were employed in order to express the thermoelastic signal, including the second-order effect. Tests have been carried out to investigate the differences in SIF evaluation between the proposed approach and the classical one. A first qualitative evaluation of the importance of considering second-order effects in the thermoelastic signal in proximity of the crack tip in two loading conditions at two different loading ratios, R = 0.1 and R = 0.5, consisted of comparing the experimental signal and synthetic TSA maps. Moreover, the SIF, evaluated with the proposed and classical approaches, was compared with values from the ASTM standard formulas. The new formulation demonstrates its improved capability for describing the stress distribution in the proximity of the crack tip. The effect of the correction cannot be neglected in either Williams’s or Westergaard’s model

    Three-dimensional Magnetic Resonance Imaging–based Printed Models of Prostate Anatomy and Targeted Biopsy-proven Index Tumor to Facilitate Patient-tailored Radical Prostatectomy—A Feasibility Study

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    In this prospective single-center feasibility study, we demonstrate that the use of three-dimensional (3D)-printed prostate models support nerve-sparing radical prostatectomy (RP) and intraoperative frozen sectioning (IFS) in ten men suffering from intermediate- and high-risk prostate cancer (PC), of whom seven harbored pT3 disease. Patient-specific 3D resin models were printed based on preoperative multiparametric magnetic resonance imaging (mpMRI) to provide an exact 3D impression of significant tumor lesions. RP and IFS were planned in a patient-tailored fashion. The 36-region Prostate Imaging Reporting and Data System (PI-RADS) v2.0 scheme was used to compare the MRI/3D print with whole-mount histopathology. In all cases, localization of the index lesion was correctly displayed by MRI and the 3D model. Localization of significant PC lesions correlated significantly (Pearson`s correlation coefficient of 0.88; p <  0.001). In addition, a significant correlation of the width, length, and volume of the tumor and prostate gland, derived from the printed model and histopathology, was found, using Pearson's correlation analyses and Bland-Altman plots. In conclusion, 3D-printed prostate models correlate well with final pathology and can be used to tailor RP. PATIENT SUMMARY: The use of three-dimensional (3D)-printed prostate models based on preoperative magnetic resonance imaging (MRI) may improve prostatectomy outcome. This study confirmed the accuracy of 3D-printed prostates compared with pathology from radical prostatectomy specimens. Thus, MRI-derived 3D-printed prostate models can assist in prostate cancer surgery

    Update of Laparoscopic Surgery in Borderline Ovarian Tumor: Systematic Review

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    Background: Borderline ovarian tumor (BOT) predominantly affects young women and is often diagnosed at an early stage. BOT accounts for 15% of all epithelial tumors. In this regard, a minimally invasive surgical approach and the ability to preserve fertility, without increasing the incidence of recurrences or worsening the prognosis, are crucial. This review aims to provide an update on the role and indications of laparoscopic surgery in BOTs. Methods: The electronic research was performed on Pubmed, Medline, and Embase. Articles published in the last 20 years (2004–2023) were included, and the following keywords were used: ‘borderline ovarian tumor’ and ‘laparoscopic surgery’, ‘borderline ovarian tumor’ and ‘minimally invasive surgery’, ‘borderline ovarian tumor’ and ‘fertility sparing’, ‘borderline ovarian tumor’ and ‘recurrence’ and ‘Borderline ovarian tumor’ and ‘relapse’. The agreement about potential relevance was reached by consensus of the researchers and according to PRISMA statement guidelines. We thoroughly reviewed all bibliographies to assess the inclusion of any further eligible studies. We excluded studies that did not align with the study’s objectives. Results: The electronic database search yielded 767 total studies. Of whom, 188 were published before 2004, 84 were case reports, and 45 were not in the English language. Of the remaining 450 studies, 148 were considered eligible for the study. We included 20 studies in this review. Conclusions: Despite the latest guidelines recommending an open approach for the treatment of BOT, the laparoscopic approach has gained popularity as a feasible and safe alternative. The use of an endo-bag, along with advanced laparoscopic skills, has made the minimally invasive approach increasingly safe, with oncological outcomes almost comparable to those of reference. Moreover, in the context of fertility-sparing surgery (FSS), laparoscopy seems to be associated with improved obstetrical outcomes, without detrimental effects on overall survival and disease-free survival. Therefore, the laparoscopic approach in the treatment of BOT appears to be a safe and effective option, especially in the case of FSS

    SP701-A-Growing and Harvesting Switchgrass for Ethanol Production in Tennessee

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    Switchgrass is a warm-season perennial grass native to North America. The plant can reach heights up to 10 feet with an extensive root system. Once established, switchgrass well-managed for biomass should have a productive life of 10-20 years. Within the stand, switchgrass is an extremely strong competitor. However, it is not considered an invasive plant. Switchgrass adapts well to a variety of soil and climatic conditions. It is most productive on moderately well to well-drained soils of medium fertility and a soil pH at 5.0 or above. The high cellulosic content of switchgrass makes it a favorable feedstock for ethanol production. It is anticipated that switchgrass can yield sufficient biomass to produce approximately 500 gallons of ethanol per acre. While the Tennessee Biofuels Initiative includes a demonstration plant to make ethanol from switchgrass, the market for switchgrass as an energy crop remains limited. Producers will likely need to be located within 30 to 50 miles of a cellulosic ethanol plant. Producing switchgrass for energy generally occurs under some form of contractual arrangement with the end-user. To reap potential benefits from using switchgrass for cellulosic ethanol production, the system of production must be profitable for farmers and energy producers, as well as cost effective for consumers

    Face perception enhances insula and motor network reactivity in Tourette syndrome

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    Tourette syndrome is a neurodevelopmental disorder, characterised by motor and phonic tics. Tics are typically experienced as avolitional, compulsive, and associated with premonitory urges. They are exacerbated by stress and can be triggered by external stimuli, including social cues like the actions and facial expressions of others. Importantly, emotional social stimuli, with angry facial stimuli potentially the most potent social threat cue, also trigger behavioural reactions in healthy individuals, suggesting that such mechanisms may be particularly sensitive in people with Tourette syndrome. Twenty-one participants with Tourette syndrome and 21 healthy controls underwent functional magnetic resonance imaging while viewing faces wearing either neutral or angry expressions to quantify group differences in neural activity associated with processing social information. Simultaneous video recordings of participants during neuroimaging enabled us to model confounding effects of tics on task-related responses to the processing of faces. In both Tourette syndrome and control participants, face stimuli evoked enhanced activation within canonical face perception regions, including the occipital face area and fusiform face area. However, the Tourette syndrome group showed additional responses within the anterior insula to both neutral and angry faces. Functional connectivity during face viewing was then examined in a series of psychophysiological interactions. In Tourette syndrome participants, the insula showed functional connectivity with a set of cortical regions previously implicated in tic generation: the pre-supplementary motor area, premotor cortex, primary motor cortex, and the putamen. Furthermore, insula functional connectivity with the globus pallidus and thalamus varied in proportion to tic severity, while supplementary motor area connectivity varied in proportion to premonitory sensations, with insula connectivity to these regions increasing to a greater extent in patients with worse symptom severity. In addition, the occipital face area showed increased functional connectivity in Tourette syndrome participants with posterior cortical regions, including primary somatosensory cortex, and occipital face area connectivity with primary somatosensory and primary motor cortices varied in proportion to tic severity. There were no significant psychophysiological interactions in controls. These findings highlight a potential mechanism in Tourette syndrome through which heightened representation within insular cortex of embodied affective social information may impact the reactivity of subcortical motor pathways, supporting programmed motor actions that are causally implicated in tic generation. Medicinal and psychological therapies that focus on reducing insular hyper-reactivity to social stimuli may have potential benefit for tic reduction in people with Tourette syndrome

    Patterns of Retinal Damage Facilitate Differential Diagnosis between Susac Syndrome and MS

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    Susac syndrome, a rare but probably underdiagnosed combination of encephalopathy, hearing loss, and visual deficits due to branch retinal artery occlusion of unknown aetiology has to be considered as differential diagnosis in various conditions. Particularly, differentiation from multiple sclerosis is often challenging since both clinical presentation and diagnostic findings may overlap. Optical coherence tomography is a powerful and easy to perform diagnostic tool to analyse the morphological integrity of retinal structures and is increasingly established to depict characteristic patterns of retinal pathology in multiple sclerosis. Against this background we hypothesised that differential patterns of retinal pathology facilitate a reliable differentiation between Susac syndrome and multiple sclerosis. In this multicenter cross-sectional observational study optical coherence tomography was performed in nine patients with a definite diagnosis of Susac syndrome. Data were compared with age-, sex-, and disease duration-matched relapsing remitting multiple sclerosis patients with and without a history of optic neuritis, and with healthy controls. Using generalised estimating equation models, Susac patients showed a significant reduction in either or both retinal nerve fibre layer thickness and total macular volume in comparison to both healthy controls and relapsing remitting multiple sclerosis patients. However, in contrast to the multiple sclerosis patients this reduction was not distributed over the entire scanning area but showed a distinct sectorial loss especially in the macular measurements. We therefore conclude that patients with Susac syndrome show distinct abnormalities in optical coherence tomography in comparison to multiple sclerosis patients. These findings recommend optical coherence tomography as a promising tool for differentiating Susac syndrome from MS
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