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Grinding, Melting and Reshaping of EoL Thermoplastic Polymers Reinforced with Recycled Carbon Fibers
Get PDFThis article assesses the technical feasibility of a recycling process based on grinding, melting and re-shaping of carbon fibers (CFs) reinforced thermoplastic polymers, in order to obtain new products that can be introduced in different markets, depending on mechanical properties retained. The idea at the basis of our study is that this kind of recycling process lies at the edge of the stages of recycling and re-use of materials, considering that the latter is preferable when considering the waste management hierarchy. Lower cost and similar mechanical strength of virgin CFs allowed the spread of recycled CFs in the automotive sector in the form of composite materials. Taking into account the Directive 2000/53/EC that sets out measures to prevent and limit waste from end-of-life (EoL) vehicles and their components, and ensures that where possible this is reused, recycled or recovered, we considered worth to investigate the recyclability of composite materials made with recycled CFs when they will reach the state of EoL materials. Considering this premise, an additional scope of this paper is therefore to provide some useful information about the possibility to perform a multiple closed loop recycling of rCF thermoplastic composites. Experiments carried out demonstrated that re-shaping of composites is technically feasible. Some square plates were produced without any setback. The mass balance of the recycling process demonstrated that about 88% of the EoL material can be recovered. Calculation of energy consumption showed that approximately 16 MJ are necessary in the treatment of 1 kg of EoL composites
Irradiation Hardening and Microstructure Characterization of Zr -1% Nb During Low Dose Neutron Irradiation
Get PDFDue to low neutron absorption cross section, high mechanical strength, high thermal conductivity and good corrosion resistance in water and steam, Zirconium alloys are widely used as fuel cladding material in nuclear reactors. During life-time of a reactor the microstructure of this alloy is affected due to, among other factors, radiation damage and hydrogen damage. In this work mechanical properties changes on neutron irradiated Zr-1wt.% Nb at low temperatures (< 100 °C) and low dose (3.5 ´ 1023 n m-2 (E > 1 MeV)) were correlated with hydrides and crystal defects evolution during irradiation. To achieve this propose, tensile tests of: 1) Non-hydrided and non-irradiated material, 2) Hydrided and non-irradiated material and 3) Hydrided and irradiated material were performed at 25 ºC and 300 ºC. Different phases, hydrides and second phase precipitates were characterized by transmission electron microscopy (TEM) techniques. For the hydrided and irradiated material, the ductility decreased sharply with respect to the hydrided and non-irradiated material, among other factors, due to the change in the microstructure produced mainly by neutron irradiation. Even if the presence of the hydride ζ (zeta) was observed, both in the irradiated and non-irradiated material, tensile tests showed that ζ-hydrides did not affect ductility, since hydrided samples are more ductile than non-hydrided samples
Influence of Sheet Conditions on In-Plane Strain Evolution via Ex-Situ Tensile Deformation of Ti-3Al-2.5V at Room Temperature
Get PDFLocalised plastic deformation evolution was examined in a near alpha Ti-3Al-2.5V alloy with indent defect and defect free surfaces using digital image correlation, an interrupted uniaxial tensile test and scanning electron microscopy. The main aim was to understand the role of the localised strain evolution at micro scale and the underlying deformation mechanisms that influence the global mechanical behaviour of the material. The microstructures captured at different stages of deformation were processed using a digital image correlation system, whose outputs were analysed through Matlab, to ascertain the localised strain evolution observed in each surface condition. This work found that the strains observed at the deformation bands along the indent defect edge, were significantly higher than those observed in the deformed β phase field. The deformation bands concentrating at the tip of the indent defect acted as a fertile site for early crack nucleation and propagation with a reduced localised fracture strain. For a defect free surface, the absence of defect zones acting as a high stress concentration site meant that strain aggregation was minimised and the α phase field was able to sufficiently accommodate the β phase deformation resulting in higher fracture strains
Controlled Cracking of Large Size Concrete Structures by a Steam Pressure Cracking Agent
Get PDFThe dismantling of large concrete structures causes environmental pollution due to the dispersion of polluted micro-particles. The purpose of this study is to develop an environmentally friendly demolition method. Steam pressure cracking (SPC) is a method that can safely and quickly separate concrete because there is less vibration compared to the explosion method. To date, the authors have shown that the direction of cracking in a small sample can be controlled by an induction hole. The principle of control is that the elastic wave of compression stress generated from the SPC reaction changes to a tensile elastic wave at the induction hole, and a crack is initiated. In this study, it was shown that the direction of crack propagation can be controlled by using induction holes in large concrete structures that are 1m on each side. Further, in the SPC method, the large amount of concrete powder generated by the explosion method is not produced, and there is no risk of secondary contamination by fine concrete powder. It was also possible to separate small pieces from the end face of the large concrete by SPC and induction holes. The area over which the crack propagated depends on the energy generated from the SPC agent, and the relationship was linear. By applying an SPC agent to dismantling large concrete structures, we can achieve controlled cracking safely and quickly without any environmental pollution. 
Supervised Learning for Binary Classification on US Adult Income
Get PDFIn this project, various binary classification methods have been used to make predictions about US adult income level in relation to social factors including age, gender, education, and marital status. We first explore descriptive statistics for the dataset and deal with missing values. After that, we examine some widely used classification methods, including logistic regression, discriminant analysis, support vector machine, random forest, and boosting. Meanwhile, we also provide suitable R functions to demonstrate applications. Various metrics such as ROC curves, accuracy, recall and F-measure are calculated to compare the performance of these models. We find the boosting is the best method in our data analysis due to its highest AUC value and the highest prediction accuracy. In addition, among all predictor variables, we also find three variables that have the largest impact on the US adult income level
Prevention of Protein Oxidation in Chicken Meat during Chilled Storage Using Chitosan Gelatin Films with Green Tea Extracts
Get PDFIn present study, the usability of chitosan and gelatin (1:1) films incorporated with green tea extract (GTE) to improve the shelf life of the chicken meat stored in chilled condition was evaluated. The extract of green tea was evaluated for its phenolic content, antioxidant activity and ferric ion chealating ability. The ChGel films possessed antimicrobial activity and inactivated approximately 3 log cfu/ ml of K. pneumoniae, S. typhi var. Weltevreden, S. typhi var. Oslo, Y. enterocolitica, E. feacalis, B. cereus, E. coli and S. aureus in 3 hours. Incorporation of GTE influenced the optical and mechanical properties of the films. Chicken samples without films were observed to be microbiologically safe for not more than 6 days, while ChGel and ChGel-GTE films improved the microbial safety of chicken samples till day 13. ChGel-GTE films also prevented lipid peroxidation in samples as evident by TBARS value (day 10: control: 1.14; ChGel-GTE: 0.21 mg MDA eq/kg). Protein oxidation during chilled storage of chicken was also prevented by ChGel-GTE by inhibiting protein carbonylation, loss of free thiols groups in protein and lowering the number of disulphde bonds. This study supports use of ChGel films with GTE for enhancing the safety of stored chicken meat not only by maintaining the microbial quality of the samples but also preventing oxidative changes which can hamper the functional, nutritional and sensorial properties
Impact of Alternative Thermal and Non-Thermal Processing on the Enzymatic Activity of Papaya and Strawberry Nectars and Their Blends
Get PDFPectin methylesterase (PME) in papaya nectar results in undesirable gel formation and peroxidase (POD) in strawberry nectar leads to nutrient loss, browning, and off-flavor production. Because of this, the effect of alternative processing techniques including ultra high temperature (UHT, 20-135°C, 1-3 s), high pressure processing (HPP, 20 or 60°C, 200-600 MPa) and irradiation (0-10 kGy) on PME and POD activity in papaya and strawberry nectar and their respective blends were compared to traditional thermal processing (80-130°C, 0-10 min). Traditional thermal (110°C, 5 min, 71.5% reduction) and UHT (110°C, 1-3 s, 98.0% reduction) processing were able to sufficiently reduce PME activity and prevent gel formation in papaya nectar. PME reduction was enhanced by synergistic reductions in nectar blends after UHT at 80°C. HPP was unable to prevent gel formation in papaya nectar, with enhanced activity at 400 MPa. Exposure of a blend 50P:50S to 10 kGy irradiation prevented gel formation. UHT enhanced POD activity at 110°C and synergistic reductions resulted for POD activity in nectar blends after irradiation. These findings highlight the benefits of alternative processing in reducing enzyme activity in fruit nectars and nectar blends
Deep Learning Based Human Emotional State Recognition in a Video
Get PDFHuman emotions play significant role in everyday life. There are a lot of applications of automatic emotion recognition in medicine, e-learning, monitoring, marketing etc. In this paper the method and neural network architecture for real-time human emotion recognition by audio-visual data are proposed. To classify one of seven emotions, deep neural networks, namely, convolutional and recurrent neural networks are used. Visual information is represented by a sequence of 16 frames of 96 × 96 pixels, and audio information - by 140 features for each of a sequence of 37 temporal windows. To reduce the number of audio features autoencoder was used. Audio information in conjunction with visual one is shown to increase recognition accuracy up to 12%. The developed system being not demanding to be computing resources is dynamic in terms of selection of parameters, reducing or increasing the number of emotion classes, as well as the ability to easily add, accumulate and use information from other external devices for further improvement of classification accuracy
Nutritional Composition of Selected Commercially Sold Ready-to-eat Indian Meat and Vegetable Curried Dishes
Get PDFA significant influence of dietary and nutrition transition is on the food behaviour of populace reflected in higher dependence on processed or catered foods. The traditional home cooked meals have been largely replaced by street or restaurant foods. While the nutritional composition of processed foods is declared on the label, there is no such information available regarding catered foods and the consumer cannot make an informed choice while selecting food at an eatery. With this premise, the present study was undertaken to analyse the nutritional composition of selected meat and vegetables based Indian dishes sourced from three different catering establishments. Similar dishes were also prepared in laboratory and the nutritional value computed using food composition database. The dishes selected were curries made with chicken, mutton, fish, mixed vegetable, Malai kofta (potato and cheese balls in creamy gravy) and Gobi Manchurian (deep fried spiced cauliflower snack). The results revealed that there were wide variations in the energy and fat content of foods sourced from different eateries. In general, the fat content of dishes was very high. In comparison, laboratory prepared items had lesser energy and fat content. The information will help in creating a nutrient database of ready-to-eat foods and help the consumer in selectin of dishes
Studies on Alum as Milk Coagulating Agent in the Manufacture of Paneer – An Indian Cottage Cheese
Get PDFAlum is a white crystalline double sulphate of aluminum and potassium that is commonly used as an astringent. Utilising its protein binding property, alum was studied as coagulating agent of milk in the preparation of paneer. Paneer is a soft variety of cottage cheese very popular in Indian sub-continent, used in various culinary dishes. Its preparation essentially involves acid coagulation of hot milk and pressing of the hot coagulum to form a compact block which is then cooled by immersing in chilled water. Citric acid and vinegar are commonly used as coagulating agents of milk during paneer manufacture. However, when alum was used as a coagulating agent, it was observed that most of the proteins were amalgamated during coagulation process resulting in enhanced yield of paneer. It also resulted in reduced solids losses in whey. However, use of alum resulted in a slight astringency in paneer, hence it was recommended to be used in combination with common coagulant i.e. citric acid. The solids content (losses) in whey were 6.62, 6.08, and 6.32 %, respectively for citric acid, alum and citric acid + alum mixture used as coagulating agents. Similarly, the yields of paneer were 16.42, 19.04 and 16.99 %. The alum coagulated paneer looked glossy and attractive which was indicated by reflectance values of 83.75% as against 79% for control paneer sample. The paneer made by alum coagulation had slightly brittle texture