Miracle-dz/UniFAR-FTUs huggingface dataset:
Thermogravimetric analysis of resized glass and carbon fibers

Maria Clara Lessa Belone: Thermogravimetric analysis of resized glass and carbon fibers Master of Science Tampere University Master’s degree programme in Materials Engineering August 2019 The demand in growth for composite products over the years has as a consequence increased the volume of composite waste, requiring adequate waste management beyond incineration or landfilling practices. Current composite recycling methods cause an unwanted decrease in the mechanical performance of the recovered fibers due to the deterioration in their capacity to effectively interact with the polymeric matrix. Resizing the recycled glass and carbon fibers is a strategy to enable the rescue of their properties and, thus, the reuse of them on a new composite. This work focuses on the characterization of recycled and resized glass fiber and carbon fiber by Fourier transform infrared analysis (FTIR) and mainly by thermogravimetric analysis (TGA). Fibers were resized with solutions containing different concentrations of coupling agent and film former, in which the coupling agent was added only in the resizing formulation of the recycled glass fibers. Moreover, a study about the extraction of the resizing layer on the fiber’s surface by solvent and by burning is performed. The aim of this work is to determine the amount and composition of sizing on the fibers after the resizing process as well as the accuracy of TGA in the sizing characterization. The understanding of the resized fiber’s surface is important to the development of a suitable resizing method that could contribute to add value to the recycled and resized fibers and make them attractive to the market. As a result, the characterization methods have detected the presence of the sizing layer on the fiber’s surface in all studied samples. Furthermore, the amount and composition of this layer was determined. The extraction process revealed that the resizing layer had both physisorbed and chemisorbed portion either for recycled glass fibers or recycled carbon fiber. On the TGA technique, the analysis was not greatly affected by varying the heating rate from 10 K/min to 5 K/min, but great change occurred when furnace’s atmosphere was changed from nitrogen to air. In addition, TG analysis presented inaccuracies due to the small amount of sizing on the surface comparing to the mass of the fibers that was inserted on the crucible. Then, the use of other characterization methods were important to have better comprehension about the samples.
Functional dependencies between sample properties from structured molding and core mixtures

Article is devoted to functional dependencies between the parameters of structured molding and core mixtures establishment, which are determined on samples using standard and generally accepted methods. The aim of the work is properties of structured molding and core mixtures for disposable casting molds predicting accuracy improvement.To establish the general structure of proposed dependences, dimensional analysis -theorem has been used. According to theoretical studies results, functional dependencies between flaking, brittleness, strength, castings from castings molds and cores knockout work and number of parameters and properties of structured molding and core mixtures were established for the first time. These dependencies implementation will improve analysis and prediction of number of properties levels accuracy, as well as accelerate compositions of molding and core mixtures optimizing process when used in foundries. Ultimately, accuracy increasing in prediction of structured mixtures properties will entail castings quality improvement and level of cast parts nonconformance decreasing. It has been noted that, in first approximation, it’s permissible to estimate mixtures knockout ability according to their residual strength values.
Nondestructive Electromagnetic Characterization of Perfect-Electric-Conductor-Backed Uniaxial Materials

As the use of anisotropic materials in electromagnetic applications continues to proliferate, it becomes increasingly important to develop non-destructive evaluation methods for those materials in their installed configuration. In many applications, these materials are permanently affixed onto conducting bodies to reduce unwanted reflections, making it impossible to collect S21 or S12 transmission measurements as used in many techniques based on the well-known Nicolson-Ross-Weir algorithm. It also makes it impractical to reorient the sample to collect orthogonal measurements aligned with the optical axes of the anisotropic material. The goal of this research is to develop a two-reflection coefficient measurement method for extracting constitutive parameters from non-destructive interrogation of a conductor backed, non-magnetic uniaxial material using a single flanged rectangular waveguide probe. First, this dissertation presents motivation and background on complex media and their characterization. Next, a scalar-potential formulation is presented to derive Green functions describing a parallel plate region containing two layers of uniaxial material. Two measurement techniques based on those Green functions are then developed and analyzed via uncertainty analysis. One technique is validated using laboratory measurements compared to those from a mature destructive technique. Next, the advantages and disadvantages of both proposed techniques are discussed as well as suggested areas of promising future research. Ultimately, this work demonstrates that nondestructive characterization of conductor-backed uniaxial materials is not only possible, but can be achieved in an efficient, practical manner with results on par with mature destructive techniques.
Capturing cyclic mobility and preloading effects in sand using a memory-surface hardening model

Earthquake-induced build-up of pore water pressure may be responsible for reduced soil capacity, while the accumulation of shear strains may lead to a violation of serviceability limits. Predicting accurately the soil cyclic behaviour in relation to seismic numerical simulations is still a challenging topic in many respects. Efforts are required to improve several technical aspects, including the development of a reliable and complete constitutive model. This paper reports recent developments after the work of Liu et al. (2018a), and particularly about the performance of a new SANISAND formulation incorporating the memory surface concept (Corti et al., 2016). The performance of the model in terms of strain accumulation and pore pressure build-up is validated against high-quality laboratory test results. A modified dilatancy relationship is given to reproduce within the proposed framework proper cyclic mobility response. The effects of preliminary drained cyclic preloading on soil liquefaction resistance are also studied.
SENTIMENT ANALYSIS USING STRING TOKEN CLASSIFICATION ALGORITHM

Sentiment analysis is a type of data mining which involves computation of opinions, sentiments and to determine if an information or a piece of text conveys positive, negative or neutral opinion. Public opinion regarding various aspects can be found using sentiment analysis. Clustering and classification are the key techniques in sentiment analysis. Consensus clustering is better than existing clustering algorithms as it provides a stable and efficient final result. However, it has its own drawbacks. Instead of performing consensus clustering and selecting classifiers from the consolidated result, we try to develop a new classification algorithm in our work
Optimizing the geometry of the connecting rod in opposite pistons engine

The article presents the results of simulations research carried out, using Finite Element Method. The simulations were made in the Abaqus software. Studies were related to the reduction and improving of stress distribution in the connecting rod of opposite pistons combustion engine. The connecting rod has been developed in a 3D environment in the Catia software, then imported into the simulation tool, in which stress tests were performed. The connecting rod was subjected to a compression and stretching tests. Boundary conditions of forces used in simulation tests have been developed on the basis of the dynamic model created in the MSC Adams software. The study included nine iterations of geometric changes of connecting rod. Shape as well as properties such as parametric dimensions (rod length) were changed. The changes were dictated by the reduction of the maximum values of the stresses and the size of the fields with large stress values. As a result of the simulations, the improvement of the connecting rod strength was obtained by its geometrical change (which was obtained by reducing the stress fields).
Sodium Arsenic Alters the Gene Expression of some Steroidogenic Genes in TM3 Leydig Cell

Arsenic is a broad-spectrum environmental contaminant with mutagenic, teratogenic and carcinogenic effects. Due to its widespread distribution in nature, drinking water is the most common source of arsenic exposure for the general population. In this study, we aimed to determine the effect of sodium arsenite on the viability and expression profile of steroidogenic genes in TM3 Leydig cells, responsible for testicular steroidogenesis. The TM3 Leydig cells were treated with sodium arsenic (384,8 µM or 7,6 mM) for 24 hours with LH (Luteinizing hormone) stimulation. The MTT assay was used for measuring cell viability, the expression level of key genes of the steroidogenesis was evaluated using RT-qPCR.The MTT assay showed that cell viability was decreased dose-dependently. RT-qPCR demonstrated that the expression level of CYP11A1, CYP17A1 were decreased as compared to the untreated control while StAR gene expression was found to be surprisingly high in the cell exposed to high-dose arsenic ( p <0.05). The expression profile of two dehydrogenase; 17β-HSD and 3β-HSD was significantly reduced in high dose arsenic treated-group ( p <0.05); but however, no statistical significance was found in low-dose. The RT-qPCR also showed that the expression SF-1 (Steroidogenic factor-1), a key regulator of adrenal and reproductive development, was significantly decreased in both low-dose and high-dose ( p <0.05). Arsenic toxicity in Leydig cell leads to cell viability loss and cause a perturbation in key steroidogenic genes, reflecting the possible role of arsenic in infertility and male reproductive system disorders.
Gas Evolution and Gas-liquid Separator Modeling

Gas-liquid separation is a critical unit operation for oil and gas production. While there has been a large number of studies investigating the removal of liquid droplets from the gas phase, relatively little attention has been paid to the separation of gas bubbles from the liquid phase. Understanding the liquid degassing process is critical as oil and gas production is pushed towards more extreme operating conditions, particularly those involving heavy oil and high pressure environments. Current degassing guidelines rely on overly simplistic assumptions and field experience. Additionally, the entering gas and liquid phases are assumed to be in thermodynamic equilibrium with one another. Any pressure drop experienced by the multiphase stream prior to entering the separator will result in excess solution gas evolving out of solution. If the separator liquid residence time is less than the time required to re-establish equilibrium, the exiting liquid stream will then contain excess dissolved gas that will evolve out of solution further downstream. The aim of this study was twofold: construct a new experiment capable of measuring gas evolution at high pressures and develop a modeling framework for degassing within a horizontal gas-liquid separator incorporating the experimental gas evolution findings. A reference hydrocarbon system of methane and n-dodecane was used for the gas evolution experiments. Both rates of absorption and desorption were measured using the same process conditions, confirming that both mass transfer coefficients were symmetric within the experimental error. The surface renewal theory in the form of the small eddy model was found fit the data with an average error of 12.3 %. Using the separator degassing model, separation performance of entrained gas was found to be driven primarily by the liquid viscosity as well as the overall size of the initial bubble distribution. New entrained gas separation guidelines were developed using the separator model. Removing significant amounts of excess solution gas was found to be challenging using inlet conditions that also favored entrained gas separation. As more bubbles are separated from the liquid, the interfacial area available for mass transfer along with the net mass transfer rate also decrease.
Production of composites with added waste polyester-glass with their initial mechanical properties

In this article the problem of plastic recycling, and in particular waste polyester-glass, has been described. In brief, the technology for the production of new composite materials by hand, made by the contact method, using the matrix filling in the form of polyester-glass waste coming from worn-out laminates used in the construction of ship hulls. The waste used was a powdered mixture of resin particles, glass fibers, and composite particle agglomerates. A method for producing composite panels with a recyclate content of between 10% and 30% was carried out. The samples were then manufactured according to the requirements of the standard, i.e. PN-EN ISO 527-4_2000P. Samples obtained from the test plates were subjected to a static stretch test, to verify the impact of the integrated wastes on the mechanical properties of the composite. Photographs of the structure of the obtained material have also been presented. These photos showed significant differences in the composition of the resulting composites determined by the amount of waste material used. Analysis of the results indicated that increasing the amount of recyclate reduces the value of the material’s strength limit and also reduces the plasticity of the material. This article has provided an introduction to more comprehensive research on the recycling of plastics.
Structural Stabilization of Mullite Films Exposed to Oxygen Potential Gradients at High Temperatures

The oxygen shielding properties of polycrystalline Al4+2xSi2−2xO10−x (mullite) films applied as environmental barrier coatings (EBCs) on SiC fiber-reinforced SiC matrix composites (SiC/SiC) are determined by the grain boundary (GB) diffusion of oxide ions in the films, from the higher oxygen partial pressure (PO₂) surface to the lower PO₂ surface, with simultaneous GB diffusion of Al ions in the opposite direction. Herein, strategies to improve the oxygen shielding and phase stability of these films when applied to SiC/SiC substrates through bond coats are proposed, based on oxygen permeation data for mullite at high temperatures. The validity of these strategies is verified using experimental trials at 1673 K with bilayer specimens consisting of mullite films and bond coat substrates, serving as model EBCs. The data show that employing a bond coat made of β’-SiAlON rather than Si provides a source of Al for the overlying mullite film that greatly improves the phase stability of the film in the vicinity of the junction interface. Because the minimum equilibrium PO₂ values required to form SiO2 due to oxidation of the β’-SiAlON on a thermodynamic basis are significantly larger than those for oxidation of Si, the inward GB diffusion of oxide ions is effectively retarded, resulting in excellent oxygen shielding characteristics.
Effect of Health Belief Model-Based Educational Intervention About Breast Cancer on Nursing Students' Knowledge, Health Beliefs and Breast Self-Examination Practice

Background: Breast cancer is a global health emergency and it is the principal reason of cancer related deaths in Developing Countries owing to the prevailing cultural beliefs and lack of awareness among women. This study aimed to evaluate the effect of health belief model-based education about breast cancer on nursing students' knowledge, health beliefs and breast self-examination practice.Subjects and Methods: A quasi-experimental design was utilized. Setting: The study was conducted at the Faculty of Nursing, Benha University, Benha city. A purposive sample of 104 nursing students were included in the study and divided into a study group (52) and control group (52). Three tools were used for data collection; first tool: self-administrated questionnaire to collect data about the subjects' socio-demographic characteristics, and knowledge regarding breast cancer. Second tool: the health belief model scale. Third tool: an observation checklist to assess the nursing students' practice of breast self-examination.Results: A statistically significant differences were observed between the study and control groups regarding knowledge about breast cancer after educational intervention based on health belief model (t test = 19.53, P=0.000). The mean scores of perceived susceptibility, severity, benefits, cues for action, self-efficacy and total heath belief model were significantly higher in the study group compared to control group (P = 0.000). Moreover a statistically significant difference was observed between both groups regarding breast self-examination practice after educational intervention (t test = 31.266, P= 0.000). Conclusion and recommendation: The health belief model based education is an effective and efficient manner in enhancing girls’ breast self-examination practice and improving their knowledge level and health beliefs about breast cancer. Thus the current study recommends implementing health belief model based educational intervention about breast cancer at different stages of life and settings to reach all targeted women to fight the disease.
Hyperspectral x-ray imaging : a comparison of iodinated and gold nanoparticle contrast media for the application of contrast-enhanced digital mammography.

Dual energy imaging (DE) is a potential alternative breast imaging modality for patients with dense breasts. It utilises intravenous injection of contrast agent (CA) to highlight structures of interest, such as tumours. Following CA administration, images are acquired at two different energies, such that the change in attenuation of the CA across the energy range differs significantly from that of the background material, such as across its K-edge. Implementation of DE on a conventional detector requires two separate exposures, leading to a higher dose and possible patient movement between exposures, which can lead to incomplete background removal. The novelty of this work is the implementation of the DE algorithms using a hyperspectral energy-sensitive detector, HEXITEC, which gives a whole spectrum per pixel. This allows multiple energy images to be obtained simultaneously by integrating appropriate bands of the spectra acquired by each individual pixel, thereby providing a single-shot approach to DE. The ability to access a whole array of possible image combinations from a single exposure provides a powerful tool in determining the optimum beam parameters and energy ranges to produce the DE images. Two different contrast agents were compared: a clinical iodinated contrast agent and gold nanoparticles (AnNPs), which have the potential to be preferentially absorbed by tumours through targeting and functionalisation. Imaging performance was assessed for both contrast agents via reconstructed concentration calculations and CNR. The cell toxicity of each CA was also investigated using clonogenic assays to generate a cell survival curve following exposure to CA and radiation between 0-5 Gy. Both iodine and AuNPs showed good agreement with nominal values in terms of reconstructed concentration for a range of nominal concentrations (the reconstructed concentration of 200 mg/ml CA was 189 ±10 and 216 ±8 mg/ml for AuNPs and iodine respectively). Iodine outperformed AuNPs in terms of CNR. Toxicity results indicated a statistically significant decrease at the 68% confidence level in the alpha parameter of the linear quadratic dose curve with the addition of AuNPs but not with the addition of iodine, suggesting an increased toxicity with AuNPs (alpha values were found to be 0.46±1, 0.40 ±1 and 0.19±1/Gy⁻¹ for no CA, iodine and AuNPs respectively). Iodine outperformed AuNPs overall, but further work is required (including optimisation of the energy spectra) to allow the full potential of AuNPs to be determined.
The effect of electroslag remelting on the cleanliness of CrNiMoWMnV ultrahigh-strength steels

The cleanliness of ultrahigh-strength steels (UHSSs) without and with electroslag remelting (ESR) using a slag with the composition of 70% CaF2, 15% Al2O3, and 15% CaO was studied. Three experimental heats of UHSSs with different chemical compositions were designed, melted in an induction furnace, and refined using ESR. Cast ingots were forged at temperatures between 1100 and 950? C, air cooled, and their non-metallic inclusions (NMIs) were characterized using field emission scanning electron microscopy and laser scanning confocal microscopy. Thermodynamic calculations for the expected NMIs formed in the investigated steels with and without ESR were performed using FactSage 7.2 software while HSC Chemistry version 9.6. 1 was used to calculate the standard Gibbs free energies (? G? ). As a result of ESR the total impurity levels (TIL% = O% + N% + S%) and NMI contents decreased by as much as 46 % and 62 %, respectively. The NMIs were classified into four major classes: oxides, sulphides, nitrides, and complex multiphase inclusions. ESR brings about large changes in the area percentages, number densities, maximum equivalent circle diameters, and the chemical composition of the various NMIs. Most MnS inclusions were removed although some were re-precipitated on oxide or nitride inclusions leading to multiphase inclusions with an oxide or nitride core surrounded by sulphide, e.g. (MnS.Al2O3) and (MnS. TiN). Also, some sulphides are modified by Ca forming (CaMn)S and CaS.Al2O3. Some nitrides like TiN and (TiV)N are nucleated and precipitated during the solidification phase. Al2O3 inclusions were formed as a result of the addition of Al as a deoxidant to the ESR slag to prevent penetration of oxygen to the molten steel.
Effects of microstructural parameters on phase transition temperature of hydrogels in chemo-mechanical coupling fields

The stability of hydrogels can be considered as the stability of polymer networks of the gels. The external environment can lead to the change of the polymer networks stability and the phase transition of hydrogels occurs. In this paper, a new free density energy function considering the chain entanglements and functionality of junctions is presented via combining Gent hyperelastic model and Edwards-Vilgis slip-link model with Flory-Huggins theory. A numerical method is developed to solve the phase transition temperature of the hydrogels based on the given new free energy function. Influences of four microstructure parameters on phase transition temperature of hydrogels are investigated by taking PNIPAM hydrogel as an example. Analytical results show that the microstructure parameters might affect the phase transition of the hydrogels significantly.