Search results for: ribbed smoked sheets

Authors: Ammar Ayad Issa Al-Rifaie, Zuhreya Muazu, Maysam Ali Abdulwahid, Dermot Gleeson

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The aim of this audit was to examine the efficiency of alcohol history documentation and screening for hazardous drinkers at the Medical Admission Unit (MAU) of Northern General Hospital (NGH), Sheffield, to identify any potential for enhancing clinical practice. Data were collected from medical clerking sheets, ICE system and directly from 82 patients by three junior medical doctors using both CAGE questionnaire and AUDIT-C tool for newly admitted patients to MAU in NGH, in the period between January and March 2015. Alcohol consumption was documented in around two-third of the patient sample and this was documented fairly accurately by health care professionals. Some used subjective words such as 'social drinking' in the alcohol units’ section of the history. CAGE questionnaire was applied to only four patients and none of the patients had documented advice, education or referral to an alcohol liaison team. AUDIT-C tool had identified 30.4%, while CAGE 10.9%, of patients admitted to the NGH MAU as hazardous drinkers. The amount of alcohol the patient consumes positively correlated with the score of AUDIT-C (Pearson correlation 0.83). Re-audit is planned to be carried out after integrating AUDIT-C tool as labels in the notes and presenting a brief teaching session to junior doctors. Alcohol misuse screening is not adequately undertaken and no appropriate action is being offered to hazardous drinkers. CAGE questionnaire is poorly applied to patients and when satisfactory and adequately used has low sensitivity to detect hazardous drinkers in comparison with AUDIT-C tool. Re-audit of alcohol screening practice after introducing AUDIT-C tool in clerking sheets (as labels) is required to compare the findings and conclude the audit cycle.

Keywords: alcohol screening, AUDIT-C, CAGE, hazardous drinking

Procedia PDF Downloads 380

Authors: Niloofar Nazeri, Mohammad Ali Derakhshan, Reza Faridi Majidi, Hossein Ghanbari

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Injury of peripheral nervous system (PNS) can lead to loss of sensation or movement. To date, one of the challenges for surgeons is repairing large gaps in PNS. To solve this problem, nerve conduits have been developed. Conduits produced by means of electrospinning can mimic extracellular matrix and provide enough surface for further functionalization. In this research, a conductive bilayer nerve conduit with poly caprolactone (PCL), poly (lactic acid co glycolic acid) (PLGA) and MWCNT for promoting peripheral nerve regeneration was fabricated. The conduit was made of longitudinally aligned PLGA nanofibrous sheets in the lumen to promote nerve regeneration and randomly oriented PCL nanofibers on the outer surface for mechanical support. The intra-luminal guidance channel was made out of conductive aligned nanofibrous rolled sheets which are coated with laminin via dopamine. Different properties of electrospun scaffolds were investigated by using contact angle, mechanical strength, degradation time, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The SEM analysis was shown that size range of nanofibrous mat were about 600-750 nm and MWCNTs deposited between nanofibers. The XPS result was shown that laminin attached to the nanofibers surface successfully. The contact-angle and tensile tests analysis revealed that scaffolds have good hydrophilicity and enough mechanical strength. In vitro studies demonstrated that this conductive surface was able to enhance the attachment and proliferation of PC12 and Schwann cells. We concluded that this bilayer composite conduit has good potential for nerve regeneration.

Keywords: conductive, conduit, laminin, MWCNT

Procedia PDF Downloads 171

Authors: P. Leo, E. Cerri, L. Fratini, G. Buffa

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The Friction Stir Welding process uses an inert rotating mandrel and a force on the mandrel normal to the plane of the sheets to generate the frictional heat. The heat and the stirring action of the mandrel create a bond between the two sheets without melting the base metal. As matter of fact, the use of a solid state welding process limits the insurgence of defects, due to the presence of gas in melting bath, and avoids the negative effects of materials metallurgical transformation strictly connected with the change of phase. The industrial importance of Ti-6Al-4V alloy is well known. It provides an exceptional good balance of strength, ductility, fatigue and fracture properties together with good corrosion resistance and good metallurgical stability. In this paper, the authors analyze the microstructure of friction stir welded joints of Ti-6Al-4V processed at the same travel speed (35 mm/min) but at different rotation speeds (300-500 rpm). The microstructure of base material (BM), as result from both optical microscope and scanning electron microscope analysis is not homogenous. It is characterized by distorted α/β lamellar microstructure together with smashed zone of fragmented β layer and β retained grain boundary phase. The BM has been welded in the-as received state, without any previous heat treatment. Even the microstructure of the transverse and longitudinal sections of joints is not homogeneous. Close to the top of weld cross sections a much finer microstructure than the initial condition has been observed, while in the center of the joints the microstructure is less refined. Along longitudinal sections, the microstructure is characterized by equiaxed grains and lamellae. Both the length and area fraction of lamellas increases with distance from longitudinal axis. The hardness of joints is higher than that of BM. As the process temperature increases the average microhardness slightly decreases.

Keywords: friction stir welding, microhardness, microstructure, Ti-6Al-4V

Procedia PDF Downloads 348

Authors: Nasim Abuali Galehdari, Thomas J. Ryan, Ajit D. Kelkar

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In recent years, nanotechnology has played an important role in the design of an efficient radiation shielding polymeric composites. It is well known that, high loading of nanomaterials with radiation absorption properties can enhance the radiation attenuation efficiency of shielding structures. However, due to difficulties in dispersion of nanomaterials into polymer matrices, there has been a limitation in higher loading percentages of nanoparticles in the polymer matrix. Therefore, the objective of the present work is to provide a methodology to fabricate and then to characterize the functionally graded radiation shielding structures, which can provide an efficient radiation absorption property along with good structural integrity. Sandwich structures composed of Ultra High Molecular Weight Polyethylene (UHMWPE) fabric as face sheets and functionally graded epoxy nanocomposite as core material were fabricated. A method to fabricate a functionally graded core panel with controllable gradient dispersion of nanoparticles is discussed. In order to optimize the design of functionally graded sandwich composites and to analyze the stress distribution throughout the sandwich composite thickness, a finite element method was used. The sandwich panels were discretized using 3-Dimensional 8 nodded brick elements. Classical laminate analysis in conjunction with simplified micromechanics equations were used to obtain the properties of the face sheets. The presented finite element model would provide insight into deformation and damage mechanics of the functionally graded sandwich composites from the structural point of view.

Keywords: nanotechnology, functionally graded material, radiation shielding, sandwich composites, finite element method

Procedia PDF Downloads 445

Authors: Ebru Dural, M. Zulfu Asık

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Laminated glass is a kind of safety glass, which is made by 'sandwiching' two glass sheets and a polyvinyl butyral (PVB) interlayer in between them. When the glass is broken, the interlayer in between the glass sheets can stick them together. Because of this property, the hazards of sharp projectiles during natural and man-made disasters reduces. They can be widely applied in building, architecture, automotive, transport industries. Laminated glass can easily undergo large displacements even under their own weight. In order to explain their true behavior, they should be analyzed by using large deflection theory to represent nonlinear behavior. In this study, a nonlinear mathematical model is developed for the analysis of laminated glass cylindrical shell which is free in radial directions and restrained in axial directions. The results will be verified by using the results of the experiment, carried out on laminated glass cylindrical shells. The behavior of laminated composite cylindrical shell can be represented by five partial differential equations. Four of the five equations are used to represent axial displacements and radial displacements and the fifth one for the transverse deflection of the unit. Governing partial differential equations are derived by employing variational principles and minimum potential energy concept. Finite difference method is employed to solve the coupled differential equations. First, they are converted into a system of matrix equations and then iterative procedure is employed. Iterative procedure is necessary since equations are coupled. Problems occurred in getting convergent sequence generated by the employed procedure are overcome by employing variable underrelaxation factor. The procedure developed to solve the differential equations provides not only less storage but also less calculation time, which is a substantial advantage in computational mechanics problems.

Keywords: laminated glass, mathematical model, nonlinear behavior, PVB

Procedia PDF Downloads 288

Authors: Sara Honarparast, Omar Chaallal

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Reinforced concrete (RC) coupled shear walls (CSWs) are very effective structural systems in resisting lateral loads due to winds and earthquakes and are particularly used in medium- to high-rise RC buildings. However, most of existing old RC structures were designed for gravity loads or lateral loads well below the loads specified in the current modern seismic international codes. These structures may behave in non-ductile manner due to poorly designed joints, insufficient shear reinforcement and inadequate anchorage length of the reinforcing bars. This has been the main impetus to investigate an appropriate strengthening method to address or attenuate the deficiencies of these structures. The objective of this paper is to twofold: (i) evaluate the seismic performance of existing reinforced concrete coupled shear walls under reversed cyclic loading; and (ii) investigate the seismic performance of RC CSWs strengthened with externally bonded (EB) carbon fiber reinforced polymer (CFRP) sheets. To this end, two CSWs were considered as follows: (a) the first one is representative of old CSWs and therefore was designed according to the 1941 National Building Code of Canada (NBCC, 1941) with conventionally reinforced coupling beams; and (b) the second one, representative of new CSWs, was designed according to modern NBCC 2015 and CSA/A23.3 2014 requirements with diagonally reinforced coupling beam. Both CSWs were simulated using ANSYS software. Nonlinear behavior of concrete is modeled using multilinear isotropic hardening through a multilinear stress strain curve. The elastic-perfectly plastic stress-strain curve is used to simulate the steel material. Bond stress–slip is modeled between concrete and steel reinforcement in conventional coupling beam rather than considering perfect bond to better represent the slip of the steel bars observed in the coupling beams of these CSWs. The old-designed CSW was strengthened using CFRP sheets bonded to the concrete substrate and the interface was modeled using an adhesive layer. The behavior of CFRP material is considered linear elastic up to failure. After simulating the loading and boundary conditions, the specimens are analyzed under reversed cyclic loading. The comparison of results obtained for the two unstrengthened CSWs and the one retrofitted with EB CFRP sheets reveals that the strengthening method improves the seismic performance in terms of strength, ductility, and energy dissipation capacity.

Keywords: carbon fiber reinforced polymer, coupled shear wall, coupling beam, finite element analysis, modern code, old code, strengthening

Procedia PDF Downloads 172

Authors: W. Stawiński, A. Wegrzyn, O. M. Freitas, S. A. Figueiredo

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Water is a life supporting resource, crucial for humanity and essential for natural ecosystems, which have been endangered by developing industry and increasing human population. Dyes are common in effluents discharged by various industries such as paper, plastics, food, cosmetics, and textile. They produce toxic effects on animals and disturb natural biological processes in receiving waters. Having complex molecular structure and resistance to biological decomposition they are problematic and difficult to be treated by conventional methods. In the search of efficient and sustainable method, sorption has been getting more interest in application to wastewaters treatment. Clays are minerals that have a layer structure based on phyllosilicate sheets that may carry a charge, which is balanced by ions located between the sheets. These charge-balancing ions can be exchanged resulting in very good ion-exchange properties of the material. Modifications of clays enhance their properties, producing a good and inexpensive sorbent for the removal of pollutants from wastewaters. The presented work proves that the treatment of a clay, vermiculite, with nitric acid followed by washing in citric acid strongly increases the sorption of two cationic dyes, methylene blue (C.I. 52015) and astrazon red (C.I. 110825). Desorption studies showed that the best eluent for regeneration is a solution of NaCl in ethanol. Cycles of sorption and desorption in column system showed no significant deterioration of sorption capacity and proved that the material shows a very good performance as sorbent, which can be recycled and reused. The results obtained open new possibilities of further modifications on vermiculite and modifications of other materials in order to get very efficient sorbents useful for wastewater treatment.

Keywords: cationic dyestuffs, sorption and regeneration, vermiculite, wastewater treatment

Procedia PDF Downloads 226

Authors: Domenico Carmelo Mongelli

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The context is that of great uncertainty in the 27 countries belonging to the European Union which has adopted an epochal measure: the elimination of internal combustion engines for the traction of road vehicles starting from 2035 with complete replacement with electric vehicles. If on the one hand there is great concern at various levels for the unpreparedness for this change, on the other the Scientific Community is not preparing accurate studies on the problem, as the scientific literature deals with single aspects of the issue, moreover addressing the issue at the level of individual countries, losing sight of the global implications of the issue for the entire EU. The aim of the research is to fill these gaps: the technological, plant engineering, environmental, economic and employment aspects of the energy transition in question are addressed and connected to each other, comparing the current situation with the different scenarios that could exist in 2035 and in the following years until total disposal of the internal combustion engine vehicle fleet for the entire EU. The methodologies adopted by the research consist in the analysis of the entire life cycle of electric vehicles and batteries, through the use of specific databases, and in the dynamic simulation, using specific calculation codes, of the application of the results of this analysis to the entire EU electric vehicle fleet from 2035 onwards. Energy balance sheets will be drawn up (to evaluate the net energy saved), plant balance sheets (to determine the surplus demand for power and electrical energy required and the sizing of new plants from renewable sources to cover electricity needs), economic balance sheets (to determine the investment costs for this transition, the savings during the operation phase and the payback times of the initial investments), the environmental balances (with the different energy mix scenarios in anticipation of 2035, the reductions in CO2eq and the environmental effects are determined resulting from the increase in the production of lithium for batteries), the employment balances (it is estimated how many jobs will be lost and recovered in the reconversion of the automotive industry, related industries and in the refining, distribution and sale of petroleum products and how many will be products for technological innovation, the increase in demand for electricity, the construction and management of street electric columns). New algorithms for forecast optimization are developed, tested and validated. Compared to other published material, the research adds an overall picture of the energy transition, capturing the advantages and disadvantages of the different aspects, evaluating the entities and improvement solutions in an organic overall picture of the topic. The results achieved allow us to identify the strengths and weaknesses of the energy transition, to determine the possible solutions to mitigate these weaknesses and to simulate and then evaluate their effects, establishing the most suitable solutions to make this transition feasible.

Keywords: engines, Europe, mobility, transition

Procedia PDF Downloads 33

Authors: Milton Jusu

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Efforts by the Ministry of Fisheries and Marine Resources and its development partners to introduce “modern” aquaculture in Sierra Leone since the 1970s have not been successful. A number of reasons have been hypothesized, including the suggestion that the market infrastructure and demand for farmed fish were inadequate to stimulate large-scale and widespread aquaculture production in the country. We have assessed the size, structure, networks, and opportunities in fish markets using a combination of Participatory Rural Appraisals (PRAs) and questionnaire surveys conducted in a sample of 29 markets (urban, weekly, wholesale, and retail) and two hundred traders. The study showed that the local fish markets were dynamic, with very high variations in demand and supply. The markets sampled supplied between 135.2 and 9947.6 tonnes/year. Mean prices for fresh fish varied between US$1.12 and US$3.89/kg depending on species, with smoked catfish and shrimps commanding prices as high as US$7.4/kg. It is unlikely that marine capture fisheries can increase their current production levels, and these may, in fact, already be over-exploited and declining. Marine fish supplies are particularly low between July and September. More careful attention to the timing of harvests (rainy season, not dry season) and to species (catfish, not tilapia) (could help in the successful adoption of aquaculture.

Keywords: fisheries, aquaculture, marine, fish ponds

Procedia PDF Downloads 26

Authors: R. Udayabhaskar, R. V. Mangalaraja, V. T. Perarasu, Saeed Farhang Sahlevani, B. Karthikeyan, David Contreras

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Bandgap engineering of CeO₂ nanocrystals is of high interest for many research groups to meet the requirement of desired applications. The band gap of CeO₂ nanostructures can be modified by varying the particle size, morphology and dopants. Anchoring the metal oxide nanostructures on graphene sheets will result in composites with improved properties than the parent materials. The presence of graphene sheets will acts a support for the growth, influences the morphology and provides external paths for electronic transitions. Thus, the controllable synthesis of ceria:graphene composites with various morphologies and the understanding of the optical properties is highly important for the usage of these materials in various applications. The development of ceria and ceria:graphene composites with low cost, rapid synthesis with tunable optical properties is still desirable. By this work, we discuss the synthesis of pure ceria (nanospheres) and ceria:graphene composites (nano-rice like morphology) by using commercial microwave oven as a cost effective and environmentally friendly approach. The influence of the graphene on the crystallinity, morphology, band gap and luminescence of the synthesized samples were analyzed. The average crystallite size obtained by using Scherrer formula of the CeO₂ nanostructures showed a decreasing trend with increasing the graphene loading. The higher graphene loaded ceria composite clearly depicted morphology of nano-rice like in shape with the diameter below 10 nm and the length over 50 nm. The presence of graphene and ceria related vibrational modes (100-4000 cm⁻¹) confirmed the successful formation of composites. We observed an increase in band gap (blue shift) with increasing loading amount of graphene. Further, the luminescence related to various F-centers was quenched in the composites. The authors gratefully acknowledge the FONDECYT Project No.: 3160142 and BECA Conicyt National Doctorado2017 No. 21170851 Government of Chile, Santiago, for the financial assistance.

Keywords: ceria, graphene, luminescence, blue shift, band gap widening

Procedia PDF Downloads 146

Authors: Jemal Ebrahim Dessie, Lukács Zsolt

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High-strength aluminum alloys have drawn a lot of attention because of the expanding demand for lightweight vehicle design in the automotive sector. Due to poor formability at room temperature, warm and hot forming have been advised. However, warm and hot forming methods need more steps in the production process and an advanced tooling system. In contrast, since ordinary tools can be used, forming sheets at room temperature in the W temper condition is advantageous. However, springback of supersaturated sheets and their thinning are critical challenges and must be resolved during the use of this technique. In this study, AA6082-T6 aluminum alloy was solution heat treated at different oven temperatures and times using a specially designed and developed furnace in order to optimize the W-temper heat treatment temperature. A U-shaped bending test was carried out at different time periods between W-temper heat treatment and forming operation. Finite element analysis (FEA) of U-bending was conducted using AutoForm aiming to validate the experimental result. The uniaxial tensile and unload test was performed in order to determine the kinematic hardening behavior of the material and has been optimized in the Finite element code using systematic process improvement (SPI). In the simulation, the effect of friction coefficient & blank holder force was considered. Springback parameters were evaluated by the geometry adopted from the NUMISHEET ’93 benchmark problem. It is noted that the change of shape was higher at the more extended time periods between W-temper heat treatment and forming operation. Die radius was the most influential parameter at the flange springback. However, the change of shape shows an overall increasing tendency on the sidewall as the increase of radius of the punch than the radius of the die. The springback angles on the flange and sidewall seem to be highly influenced by the coefficient of friction than blank holding force, and the effect becomes increases as increasing the blank holding force.

Keywords: aluminum alloy, FEA, springback, SPI, U-bending, W-temper

Procedia PDF Downloads 71

Authors: Lahoucine Zaama, Sanae Douama

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In this work, we present the results of a dosimetry study in a Moroccan radiology department . The results are compared with those of a similar study in France. Furthermore, it determines the coefficient of transmission of the lead sheets of different thicknesses depending on the voltage (KV) in a direct exposure. The objective of this study is to choose the thickness of the radiation means to determine the leaf sample sealed with the smallest percentage value radiation transmission, and that in the context of optimization. Thus the comparison among the studies is essential to consider conduct studies and research in this framework to achieve the goal of optimization.

Keywords: radiology, dosimetry, radiation, dose, transmission

Procedia PDF Downloads 465

Authors: P. Fernández-Morales, D. Peláez, C. Isaza, J. M. Meza, E. Mendoza

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Mg AZ31B alloy sheets were processed through equal-channel angular sheet drawing (ECASD) process, following the route A and C at room temperature and varying the processing speed. SEM was used to analyze the microstructure. The grain size was refined and presence of twins was observed. Vickers microhardness and tensile testing were carried out to evaluate the mechanical properties, showing in general; a remarkable increase in the first pass and slight increases during subsequent passes and, that the route C produces better uniform properties distribution through the thickness of the samples.

Keywords: ECASD, Mg Alloy, mechanical properties, microstructure

Procedia PDF Downloads 327

Authors: Milton Jusu, Moses Koroma

Abstract:

Efforts by the Ministry of Fisheries and Marine Resources and its development partners to introduce “modern” aquaculture in Sierra Leone since the 1970s have not been successful. A number of reasons have been hypothesized, including the suggestion that the market infrastructure and demand for farmed fish were inadequate to stimulate large-scale and widespread aquaculture production in the country. We have assessed the size, structure, networks and opportunities in fish markets using a combination of Participatory Rural Appraisals (PRAs) and questionnaire surveys conducted in a sample of 29 markets (urban, weekly, wholesale and retail) and two hundred traders. The study showed that the local fish markets were dynamic, with very high variations in demand and supply. The markets sampled supplied between 135.2 and 9947.6 tonnes/year. Mean prices for fresh fish varied between US$1.12 and US$3.89/kg depending on species, with smoked catfish and shrimps commanding prices as high as US$7.4/kg. It is unlikely that marine capture fisheries can increase their current production levels, and these may, in fact, already be over-exploited and declining. Marine fish supplies are particularly low between July and September. More careful attention to the timing of harvests (rainy season, not dry season) and to species (catfish, not tilapia) (could help in the successful adoption of aquaculture.

Keywords: fisheries and aquaculture, fish market, marine fish supplies, harvests

Procedia PDF Downloads 23

Authors: Evelyne Nguegwouo, Raoul Fonkem Sonfack Tsakem, Abel Wade, Gabriel Nama Medoua, Kamgaing Theophile

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Fresh and smoked fish are widely consumed in Cameroon. The traditional nature of smoking, the lack of hygiene in production, the poor preservation of stocks and the long storage time for certain types of fish considerably favor the contamination of products by molds, which secrete toxic molecules called mycotoxins. Today there are more than 400 types of mycotoxins, Aflatoxins being the most formidable. These toxins are considered carcinogenic in humans. It is in this perspective that we proposed to evaluate the total Aflatoxins in the fish marketed and consumed by the populations of the city of Yaoundé in Cameroon. On the one hand, it was a question of conducting a survey of fish consumers and sellers in points of sale, sampling fish of three species [Marquereau (Scomber scombrus), Cod (Gadus morhua) and Bifaka (Ethmalosa fimbriata)], randomly in some markets of the city to evaluate the total Aflatoxins contents (B1, B2, G1, G2) by the quantitative ELISA method and finally to estimate the level of exposure of the populations. It emerges from this study that of the 30 samples analyzed, 96.1% contained total Aflatoxins and two samples had total Aflatoxins levels above the standard, which is 20 ppb. These first results show that the risk is present in Cameroon and in order to improve the quality of marketed fish in terms of mycotoxins, a more thorough control must be done from the production chain to the consumer.

Keywords: aflatoxins, evaluation, exposure, mycotoxins, fish

Procedia PDF Downloads 44

Authors: Danny Fraser, James Zhang

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Aim of the study: Our study aims to identify any statistically significant evidence as it relates to PROMs for mastectomy and implant-based reconstruction to guide future surgical management. Method: The demographic, pre and post-operative treatment and implant characteristics were collected of all patients at Basildon hospital who underwent breast reconstruction from 2017-2023. We used the Breast-Q psychosocial well-being, physical well-being, and satisfaction with breasts scales. An Independent t-test was conducted for each group, and linear regression of age and implant size. Results: 69 patients were contacted, and 39 PROMs returned. The mean age of patients was 57.6. 40% had smoked before, and 40.8% had BMI>30. 29 had pre-pectoral placement, and 40 had subpectoral placement. 17 had smooth implants, and 52 textured. Sub pectoral placement was associated with higher (75.7 vs. 61.9 p=0.046) psychosocial scores than pre pectoral, and textured implants were associated with a lower physical score than the smooth surface (34.7 VS 50.2 P=0.046). On linear regression, age was positively associated (p=0.007) with psychosocial score. Conclusion: We present a large cohort of patients who underwent breast reconstruction. Understanding the PROMs of these procedures can guide clinicians, patients and policy makers to be more informed of the course of rehabilitation of these operations. Significance: We have found that from a patient perspective subpectoral implant placement was associated with a statistically significant improvement in psychosocial scores.

Keywords: breast surgery, mastectomy, breast implants, oncology

Procedia PDF Downloads 25

Authors: Emigdio Mendoza, Patricia Fernandez, Cristian Gomez

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Magnesium alloys have generated great interest for several industrial applications because their high specific strength and low density make them a very attractive alternative for the manufacture of various components; however, these alloys present a limitation with their hexagonal crystal structure that limits the deformation mechanisms at room temperature likewise the molding components alternatives, it is for this reason that severe plastic deformation processes have taken a huge relevance recently because these, allow high deformation rates to be applied that induce microstructural changes where the deficiency in the sliding systems is compensated with crystallographic grains reorientations or crystal twinning. The present study reports a statistical analysis of process temperature, number of passes and shear angle with respect to the shear stress in severe plastic deformation process denominated 'Equal Channel Angular Sheet Drawing (ECASD)' applied to the magnesium alloy AZ31B through Python Statsmodels libraries, additionally a Post-Hoc range test is performed using the Tukey statistical test. Statistical results show that each variable has a p-value lower than 0.05, which allows comparing the average values of shear stresses obtained, which are in the range of 7.37 MPa to 12.23 MPa, lower values in comparison to others severe plastic deformation processes reported in the literature, considering a value of 157.53 MPa as the average creep stress for AZ31B alloy. However, a higher stress level is required when the sheets are processed using a shear angle of 150°, due to a higher level of adjustment applied for the shear die of 150°. Temperature and shear passes are important variables as well, but there is no significant impact on the level of stress applied during the ECASD process. In the processing of AZ31B magnesium alloy sheets, ECASD technique is evidenced as a viable alternative in the modification of the elasto-plastic properties of this alloy, promoting the weakening of the basal texture, which means, a better response to deformation, whereby, during the manufacture of parts by drawing or stamping processes the formation of cracks on the surface can be reduced, presenting an adequate mechanical performance.

Keywords: plastic deformation, strain, sheet drawing, magnesium

Procedia PDF Downloads 87

Authors: Konesh Navsaria, Itumeleng Ramodumo

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The study explored university students’ perceptions of cannabis use on academic life at a higher education institution (HEI) in Nelson Mandela Bay, South Africa. Cannabis is described as the most commonly-used drug by youth, especially those who are in tertiary institutions. The use of cannabis has both negative and positive effects; this is evident in different areas of human functioning. Cannabis usage has been debated upon in courts regarding its legalization and decriminalization, and on the 18th of September 2018, the South African High Court decriminalized cannabis for personal use. Cannabis use has increased in academic settings, and this has raised concerns about how it affects the mental health of students. A qualitative approach was used for the study with an explorative, descriptive design. Purposive sampling was used to select 15 participants for the study. Data were collected using focused-group interviews, following ethical clearance from the HEI. The collected data were analyzed and interpreted using thematic analysis, and cognitive behavioural theory was used as the theoretical framework. The research findings indicated both positive and negative influences of cannabis use on mental health. Most participants who expressed positive effects have used cannabis before, whereas most participants with negative perspectives of cannabis use on mental health are non-cannabis users. The findings revealed that participants perceived that the quantity of cannabis smoked determined whether there was a positive or negative effect on mental health; that is, large doses of cannabis were perceived as having negative effects. The research findings also revealed that the legalization of cannabis is very likely to increase its use and also highlighted precautionary measures users take to avoid the substance’s negative effects on mental health.

Keywords: cannabis use, mental health, university students, legalization

Procedia PDF Downloads 120

Authors: Vasant Reddy, Shivani A. Singh, Pravin S. More

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In the present investigation, we demonstrated the fabrication of few-layers of graphene sheets with alkali metal i.e. Rb-G using chemical route method. The obtained materials were characterized by means of chemical, structural and electrical techniques, using the ultraviolet-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and 4 points probe, respectively. The XRD studies were carried out to understand the phase of the samples where we found a sharp peak of Rb-G at 26.470. UV-Spectroscopy of Graphene and Rb-modified graphene samples shows the absorption peaks at ~248 nm and ~318 nm respectively. These analyses show that this modified material can be useful for gas sensing applications and to be used in diverse areas.

Keywords: chemical route, graphene, gas sensing, UV-spectroscopy

Procedia PDF Downloads 228

Authors: Sourabh Jain, Parul Madan

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Traffic noise pollution has become a challenging problem for all metro cities of India due to rapid urbanization, growing population and rising number of vehicles and transport development. In Delhi the prime source of noise pollution is vehicular traffic. In Delhi it is found that the ambient noise level (Leq) is exceeding the standard permissible value at all the locations. Noise barriers or enclosures are definitely useful in obtaining effective deduction of traffic noise disturbances in urbanized areas. US’s Federal Highway Administration Model (FHWA) and Calculation of Road Traffic Noise (CORTN) of UK are used to develop spread sheets for noise prediction. Spread sheets are also developed for evaluating effectiveness of existing boundary walls abutting houses in mitigating noise, redesigning them as noise barriers. Study was also carried out to examine the changes in noise level due to designed noise barrier by using both models FHWA and CORTN respectively. During the collection of various data it is found that receivers are located far away from road at Rithala and Moolchand sites and hence extra barrier height needed to meet prescribed limits was less as seen from calculations and most of the noise diminishes by propagation effect.On the basis of overall study and data analysis, it is concluded that FHWA and CORTN models under estimate noise levels. FHWA model predicted noise levels with an average percentage error of -7.33 and CORTN predicted with an average percentage error of -8.5. It was observed that at all sites noise levels at receivers were exceeding the standard limit of 55 dB. It was seen from calculations that existing walls are reducing noise levels. Average noise reduction due to walls at Rithala was 7.41 dB and at Panchsheel was 7.20 dB and lower amount of noise reduction was observed at Friend colony which was only 5.88. It was observed from analysis that Friends colony sites need much greater height of barrier. This was because of residential buildings abutting the road. At friends colony great amount of traffic was observed since it is national highway. At this site diminishing of noise due to propagation effect was very less.As FHWA and CORTN models were developed in excel programme, it eliminates laborious calculations of noise. There was no reflection correction in FHWA models as like in CORTN model.

Keywords: IFHWA, CORTN, Noise Sources, Noise Barriers

Procedia PDF Downloads 104

Authors: Khalid Al-Tahat, Khaled Zuhair Mahmoud, Ahmad Al-Mughrabi

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This paper proposes a novel methodology for enabling debugging and tracing of production web applications without affecting its normal flow and functionality. This method of debugging enables developers and maintenance engineers to replace a set of existing resources such as images, server side scripts, cascading style sheets with another set of resources per web session. The new resources will only be active in the debug session and other sessions will not be affected. This methodology will help developers in tracing defects, especially those that appear only in production environments and in exploring the behaviour of the system. A realization of the proposed methodology has been implemented in Java.

Keywords: live debugging, web application, web resources, inconsistent bugs, tracing

Procedia PDF Downloads 430

Authors: Davoud Dorranian, Hajar Sadeghi, Elmira Solati

Abstract:

Carbon nanostructures in various forms were synthesized using pulsed laser ablation of a graphite target in different liquid environment. The beam of a Q-switched Nd:YAG laser of 1064-nm wavelength at 7-ns pulse width is employed to irradiate the solid target in water, acetone, alcohol, and cetyltrimethylammonium bromide (CTAB). Then the effect of the liquid environment on the characteristic of carbon nanostructures produced by laser ablation was investigated. The optical properties of the carbon nanostructures were examined at room temperature by UV–Vis-NIR spectrophotometer. The crystalline structure of the carbon nanostructures was analyzed by X-ray diffraction (XRD). The morphology of samples was investigated by field emission scanning electron microscope (FE-SEM). Transmission electron microscope (TEM) was employed to investigate the form of carbon nanostructures. Raman spectroscopy was used to determine the quality of carbon nanostructures. Results show that different carbon nanostructures such as nanoparticles and few-layer graphene were formed in various liquid environments. The UV-Vis-NIR absorption spectra of samples reveal that the intensity of absorption peak of nanoparticles in alcohol is higher than the other liquid environments due to the larger number of nanoparticles in this environment. The red shift of the absorption peak of the sample in acetone confirms that produced carbon nanoparticles in this liquid are averagely larger than the other medium. The difference in the intensity and shape of the absorption peak indicated the effect of the liquid environment in producing the nanoparticles. The XRD pattern of the sample in water indicates an amorphous structure due to existence the graphene sheets. X-ray diffraction pattern shows that the degree of crystallinity of sample produced in CTAB is higher than the other liquid environments. Transmission electron microscopy images reveal that the generated carbon materials in water are graphene sheet and in the other liquid environments are graphene sheet and spherical nanostructures. According to the TEM images, we have the larger amount of carbon nanoparticles in the alcohol environment. FE-SEM micrographs indicate that in this liquids sheet like structures are formed however in acetone, produced sheets are adhered and these layers overlap with each other. According to the FE-SEM micrographs, the surface morphology of the sample in CTAB was coarser than that without surfactant. From Raman spectra, it can be concluded the distinct shape, width, and position of the graphene peaks and corresponding graphite source.

Keywords: carbon nanostructures, graphene, pulsed laser ablation, graphite

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Authors: Rose Mini Agoes Salim, Shahnaz Safitri

Abstract:

The aim of this study is to test the effectiveness of teaching kindness in preschool children by using several techniques. Kindness is a physical act or emotional support aimed to build or maintain relationships with others. Kindness is known to be essential in the development of moral reasoning to distinguish between the good and bad things. In this study, kindness is operationalized as several acts including helping friends, comforting sad friends, inviting friends to play, protecting others, sharing, saying hello, saying thank you, encouraging others, and apologizing. It is mentioned that kindness is crucial to be developed in preschool children because this is the time the children begin to interact with their social environment through play. Furthermore, preschool children's cognitive development makes them begin to represent the world with words, which then allows them to interact with others. On the other hand, preschool children egocentric thinking makes them still need to learn to consider another person's perspective. In relation to social interaction, preschool children need to be stimulated and assisted by adult to be able to pay attention to other and act with kindness toward them. On teaching kindness to children, the quality of interaction between children and their significant others is the key factor. It is known that preschool children learn about kindness by imitating adults on their two way interaction. Specifically, this study examines two types of teaching techniques that can be done by parents as a way to teach kindness, namely the picture-storybook reading and hand-puppet storytelling. These techniques were examined because both activities are easy to do and both also provide a model of behavior for the child based on the character in the story. To specifically examine those techniques effectiveness in teaching kindness, two studies were conducted. Study I involves 31 children aged 5-6 years old with picture-storybook reading technique, where the intervention is done by reading 8 picture books for 8 days. In study II, hand-puppet storytelling technique is examined to 32 children aged 3-5 years old. The treatments effectiveness are measured using an instrument in the form of nine colored cards that describe the behavior of kindness. Data analysis using Wilcoxon Signed-rank test shows a significant difference on the average score of kindness (p < 0.05) before and after the intervention has been held. For daily observation, a ‘kindness tree’ and observation sheets are used which are filled out by the teacher. Two weeks after interventions, an improvement on all kindness behaviors measured is intact. The same result is also gained from both ‘kindness tree’ and observational sheets.

Keywords: kindness, moral teaching, storytelling, hand puppet

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Authors: Syed W. Hasan, Zhiqun Tian

Abstract:

Wet spinning provides a facile and economic route to fabricate graphene nanofibers (GFs) on mass scale. Nevertheless, the pristine GFs exhibit significantly low electrical and mechanical properties owing to stacked graphene sheets and weak inter-atomic bonding. In this report, we present highly conductive Ag-decorated-GFs (Ag/GFs). The SEM micrographs show Ag nanoparticles (NPs) (dia ~10 nm) are homogeneously distributed throughout the cross-section of the fiber. The Ag NPs provide a conductive network for the electrons flow raising the conductivity to 1.8(10^4) S/m which is 4 times higher than the pristine GFs. Our results surpass the conductivities of graphene fibers doped with CNTs, Nanocarbon, fullerene, and Cu. The chemical and structural attributes of Ag/GFs are further elucidated through XPS, AFM and Raman spectroscopy.

Keywords: Ag nanoparticles, Conductive fibers, Graphene, Wet spinning

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Authors: S. Brahmi, S. Aitouche, M. D. Mouss

Abstract:

Every modern company should measure the value of its intellectual capital and to report to complement the traditional annual balance sheets. The purpose of this work is to measure the intellectual capital in an Algerian company (or production system) using the Weightless Wealth Tool Kit (WWTK). The results of the measurement of intellectual capital are supplemented by traditional financial ratios. The measurement was applied to the National Company of Wells Services (ENSP) in Hassi Messaoud city, in the south of Algeria. We calculated the intellectual capital (intangible resources) of the ENSP to help the organization to better capitalize on its potential of workers and their know-how. The intangible value of the ENSP is evaluated at 16,936,173,345 DA in 2015.

Keywords: financial valuation, intangible capital, intellectual capital, intellectual capital measurement

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Authors: Bingjie Wu, C. Q. Ru

Abstract:

The present work studies several reasonably expected candidate integral forms for self-attractive potential energy of a free monolayer graphene sheet. The admissibility of a specific integral form for ripple formation is verified, while all others most of the candidate integral forms are rejected based on the non-existence of stable periodic ripples. Based on the selected integral form of self-attractive potential energy, some mechanical behavior, including ripple formation and buckling, of a free monolayer grapheme sheet are discussed in details

Keywords: graphene, monolayer, ripples, van der Waals energy

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Authors: Sunthorn Sittisakuljaroen

Abstract:

The edge waviness in hot rolled steel is a common defect. Variables that effect for such defect include as raw material and machine. These variables are necessary to consider. This research studied the defect of edge waviness for SS 400 of metal sheet manufacture. Defect of metal sheets divided into two groups. The specimens were investigated on chemical composition and mechanical properties to find the difference. The results of investigate showed that not different to a standard significantly. Therefore the roll milled machine for sample need to adjustable rollers for press on metal sheet which was more appropriate to adjustable at both ends.

Keywords: edge waviness, hot rolling steel, metal sheet defect, SS 400, roll leveller

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Authors: Shahbaz Ahmed

Abstract:

This study is conducted to demonstrate the knowledge of intentional learning and incidental learning. Hypothesis of this experiment is intentional learning is better than incidental learning, participants were demonstrated and were asked to learn the 10 nonsense syllables in a specific sequence from the colored cards in the end they were asked to recall the background color of each card instead of nonsense syllables. Independent variables of the experiment are the colored cards containing nonsense syllables which are to be memorized by the participants, dependent variables are the number of correct responses made by the participant. The findings of the experiment concluded that intentional learning is better than incidental learning, hence hypothesis is proved.

Keywords: intentional learning, incidental learning, non-sense syllable cards, score sheets

Procedia PDF Downloads 489

Authors: Meng-Huan Wu, Wei-Er Wang, Tsu-Nai Wang, Wei-Jian Hsu, Vincent Chin-Hung Chen

Abstract:

Objective: Studies have reported a strong link between asthma and bipolar disorder. We conducted a 17-year community-based large cohort study to examine the relationship between asthma, early smoking initiation, and bipolar disorder during adolescence and early adulthood. Methods: A total of 162,766 participants aged 11–16 years were categorized into asthma and non-asthma groups at baseline and compared within the observation period. Covariates during late childhood or adolescence included parental education, cigarette smoking by family members of participants, and participant’s gender, age, alcohol consumption, smoking, and exercise habits. Data for urbanicity, prednisone use, allergic comorbidity, and Charlson comorbidity index were acquired from the National Health Insurance Research Database. The Cox proportional-hazards model was used to evaluate the association between asthma and bipolar disorder. Results: Our findings revealed that asthma increased the risk of bipolar disorder after adjustment for key confounders in the Cox proportional hazard regression model (adjusted HR: 1.31, 95% CI: 1.12-1.53). Hospitalizations or visits to the emergency department for asthma exhibited a dose–response effect on bipolar disorder (adjusted HR: 1.59, 95% CI: 1.22-2.06). Patients with asthma with onset before 20 years of age who smoked during late childhood or adolescence had the greatest risk for bipolar disorder (adjusted HR: 3.10, 95% CI: 1.29-7.44). Conclusions: Patients newly diagnosed with asthma had a 1.3 times higher risk of developing bipolar disorder. Smoking during late childhood or adolescence increases the risk of developing bipolar disorder in patients with asthma.

Keywords: adolescence, asthma, smoking, bipolar disorder, early adulthood

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Authors: Michael Tupý, Vít Petránek

Abstract:

The paper is focused on testing of the poly(vinyl butyral) (PVB) layer which had the function of a CO2 insulating protection against concrete and mortar carbonation. The barrier efficiency of PVB was verified by the measurement of diffusion characteristics. Two different types of PVB were tested; original extruded PVB sheet and PVB sheet made from PVB dispersion which was obtained from recycled windshields. The work deals with the testing CO2 diffusion when polymer sheets were exposed to a CO2 atmosphere (10% v/v CO2) with 0% RH. The excellent barrier capability against CO2 permeability of original and also recycled types of PVB layers was observed. This application of PVB waste can bring advantageous use in civil engineering and significant environmental contribution.

Keywords: windshield, poly(vinyl butyral), mortar, diffusion, carbonatation, polymer waste

Procedia PDF Downloads 398