Search results for: mechanical behaviour

Authors: Nuray Uçar, Mervin Ölmez, Özge Alptoğa, Nilgün K. Yavuz, Ayşen Önen

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In recent years, research on continuous graphene oxide fibers has been intensified. Therefore, many factors of production stages are being studied. In this study, the effect of exfoliation time and presence of activated carbon particle (ACP) on graphene oxide fiber’s properties has been analyzed. It has been seen that cross-sectional appearance of sample with ACP is harsh and porous because of ACP. The addition of ACP did not change the electrical conductivity. However, ACP results in an enormous decrease of mechanical properties. Longer exfoliation time results to higher crystallinity degree, C/O ratio and less d space between layers. The breaking strength and electrical conductivity of sample with less exfoliation time is some higher than sample with high exfoliation time.

Keywords: activated carbon, coagulation by wet spinning, exfoliation, graphene oxide fiber

Procedia PDF Downloads 323

Authors: Nabiha Bouafia, Asma Ben Cheikh, Asma Ammar, Olfa Ezzi, Mohamed Mahjoub, Khaoula Meddeb, Imed Chouchene, Hamadi Boussarsar, Mansour Njah

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Background: Hospital acquired infections (HAI) cause significant morbidity, mortality, length of stay and hospital costs, especially in the intensive care unit (ICU), because of the debilitated immune systems of their patients and exposure to invasive devices. The aims of this study were to determine the rate and the risk factors of HAI in an ICU of a university hospital in Tunisia. Materials/Methods: A prospective study was conducted in the 8-bed adult medical ICU of a University Hospital (Sousse Tunisia) during 14 months from September 15th, 2015 to November 15th, 2016. Patients admitted for more than 48h were included. Their surveillance was stopped after the discharge from ICU or death. HAIs were defined according to standard Centers for Disease Control and Prevention criteria. Risk factors were analyzed by conditional stepwise logistic regression. The p-value of < 0.05 was considered significant. Results: During the study, 192 patients had admitted for more than 48 hours. Their mean age was 59.3± 18.20 years and 57.1% were male. Acute respiratory failure was the main reason of admission (72%). The mean SAPS II score calculated at admission was 32.5 ± 14 (range: 6 - 78). The exposure to the mechanical ventilation (MV) and the central venous catheter were observed in 169 (88 %) and 144 (75 %) patients, respectively. Seventy-three patients (38.02%) developed 94 HAIs. The incidence density of HAIs was 41.53 per 1000 patient day. Mortality rate in patients with HAIs was 65.8 %( n= 48). Regarding the type of infection, Ventilator Associated Pneumoniae (VAP) and central venous catheter Associated Infections (CVC AI) were the most frequent with Incidence density: 14.88/1000 days of MV for VAP and 20.02/1000 CVC days for CVC AI. There were 5 Peripheral Venous Catheter Associated Infections, 2 urinary tract infections, and 21 other HAIs. Gram-negative bacteria were the most common germs identified in HAIs: Multidrug resistant Acinetobacter Baumanii (45%) and Klebsiella pneumoniae (10.96%) were the most frequently isolated. Univariate analysis showed that transfer from another hospital department (p= 0.001), intubation (p < 10-4), tracheostomy (p < 10-4), age (p=0.028), grade of acute respiratory failure (p=0.01), duration of sedation (p < 10-4), number of CVC (p < 10-4), length of mechanical ventilation (p < 10-4) and length of stay (p < 10-4), were associated to high risk of HAIS in ICU. Multivariate analysis reveals that independent risk factors for HAIs are: transfer from another hospital department: OR=13.44, IC 95% [3.9, 44.2], p < 10-4, duration of sedation: OR= 1.18, IC 95% [1.049, 1.325], p=0.006, high number of CVC: OR=2.78, IC 95% [1.73, 4.487], p < 10-4, and length of stay in ICU: OR= 1.14, IC 95% [1.066,1.22], p < 10-4. Conclusion: Prevention of nosocomial infections in ICUs is a priority of health care systems all around the world. Yet, their control requires an understanding of epidemiological data collected in these units.

Keywords: healthcare associated infections, incidence, intensive care unit, risk factors

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Authors: A. K. Sarathe, N. P. Patidar

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The Indian automobile sector is comprised of independent manufacturers and joint ventures with their foreign counterpart companies by making use of the Foreign Direct Investment policy of the Government of India. These manufacturers started capturing the hearts of Indian customers with their choice of technological and innovative product features, with quality and reliability. This transformed the automobile scene from a “sellers market to buyers market”. The potential benefits from the auto sector have been recognized by the planners, managers, and administrators of both the sectors –government and private. Generation of employment for the readily available technical workforce has been achieved not only through the manufacturers, but also through the growing ancillaries and service providers of the auto industries. The main purpose of this paper is to come up with the identification of possible working areas and associated job functions of mechanical and automobile diploma holders having employment opportunities in auto sector of India.

Keywords: automobile sector, diploma holder, employment, job description

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Authors: G. Calleja-Rodriguez, N. Jimenez-Redondo, J. J. Peralta Escalante

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This research work aims at developing a solution to take advantage of the potential energy saving related to occupants behaviour estimated in between 5-30 % according to existing studies. For that purpose, the following methodology has been followed: 1) literature review and gap analysis, 2) define concept and functional requirements, 3) evaluation and feedback by experts. As result, the concept for a tool-box that implements continuous behavior change interventions named as engagement methods and based on increasing energy literacy, increasing energy visibility, using bonus system, etc. has been defined. These engagement methods are deployed through a set of ICT tools: Building Automation and Control System (BACS) add-ons services installed in buildings and Users Apps installed in smartphones, smart-TVs or dashboards. The tool-box called eTEACHER identifies energy conservation measures (ECM) based on energy behavioral change through a what-if analysis that collects information about the building and its users (comfort feedback, behavior, etc.) and carry out cost-effective calculations to provide outputs such us efficient control settings of building systems. This information is processed and showed in an attractive way as tailored advice to the energy end-users. Therefore, eTEACHER goal is to change the behavior of building´s energy users towards energy efficiency, comfort and better health conditions by deploying customized ICT-based interventions taking into account building typology (schools, residential, offices, health care centres, etc.), users profile (occupants, owners, facility managers, employers, etc.) as well as cultural and demographic factors. One of the main findings of this work is the common failure when technological interventions on behavioural change are done to not consult, train and support users regarding technological changes leading to poor performance in practices. As conclusion, a strong need to carry out social studies to identify relevant behavioural issues and to identify effective pro-evironmental behavioral change strategies has been identified.

Keywords: energy saving, behavioral bhange, building users, engagement methods, energy conservation measures

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Authors: Betül Özgenç, Soner Kuşlu, Sabri Çolak, Turan Çalban

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The aim of this study was investigate the leaching kinetics of ulexite in disodium hydrogen phosphate solutions in a mechanical agitation system. Reaction temperature, concentration of disodium hydrogen phosphate solutions, stirring speed, solid/liquid ratio and ulexite particle size were selected as parameters. The experimental results were successfully correlated by linear regression using Statistica program. Dissolution curves were evaluated shrinking core models for solid-fluid systems. It was observed that increase in the reaction temperature and decrease in the solid/liquid ratio causes an increase the dissolution rate of ulexite. The activation energy was found to be 63.4 kJ/mol. The leaching of ulexite was controlled by chemical reaction.

Keywords: ulexite, disodium hydrogen phosphate, leaching kinetics

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Authors: Busra Balli, Tuncay Dikici, Mustafa Toparli

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Titanium and its alloys have been used extensively over the past 25 years as biomedical materials in orthopedic and dental applications because of their good mechanical properties, corrosion resistance, and biocompatibility. It is known that the surface properties of titanium implants can enhance the cellular response and play an important role in Osseo integration. The rate and quality of Osseo integration in titanium implants are related to their surface properties. The purpose of this investigation was to evaluate the effect of sandblasting and acid etching on surface morphology, roughness, the wettability of titanium. The surface properties will be characterized by scanning electron microscopy and contact angle and roughness measurements. The results show that surface morphology, roughness, and wettability were changed and enhanced by these treatments.

Keywords: dental implant, etching, surface modifications, surface morphology, surface roughness

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Authors: Zohreh Sheidaei, Farhad Sadegh Moghanlou, Rahim Vesal

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Diseases related to leg venous system are common worldwide. An incompetent vein with deformed wall and insufficient valves affects flow field of blood and disrupts the process of blood circulating system. Having enough knowledge about the flow field through veins will help find new ways to cure the related diseases. In the present study, blood flow around a leaflet valve of a perforating vein is investigated numerically by Finite Element Method. Flow behavior and vortexes, generated around the leaflet valves, are studied considering valve opening percentage. Obtained velocity and pressure fields show mechanical stresses on vein wall and these valves and consequently introduce the regions susceptible to deformation.

Keywords: fluid flow, leaflet valve, numerical investigation, perforating vein

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Authors: Nalinee B. Suryawanshi, Vinay M. Bhandari, Laxmi Gayatri Sorokhaibam, Vivek V. Ranade

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Deep desulphurization of transportation fuels is a major environmental concern all over the world and recently prescribed norms for the sulphur content require below 10 ppm sulphur concentrations in fuels such as diesel and gasoline. The existing technologies largely based on catalytic processes such as hydrodesulphurization, oxidation require newer catalysts and demand high cost of deep desulphurization whereas adsorption based processes have limitations due to lower capacity of sulphur removal. The present work is an attempt to provide alternatives for the existing methodologies using a newer non-catalytic process based on hydrodynamic cavitation. The developed process requires appropriate combining of organic and aqueous phases under ambient conditions and passing through a cavitating device such as orifice, venturi or vortex diode. The implosion of vapour cavities formed in the cavitating device generates (in-situ) oxidizing species which react with the sulphur moiety resulting in the removal of sulphur from the organic phase. In this work, orifice was used as a cavitating device and deep desulphurization was demonstrated for removal of thiophene as a model sulphur compound from synthetic fuel of n-octane, toluene and n-octanol. The effect of concentration of sulphur (up to 300 ppm), nature of organic phase and effect of pressure drop (0.5 to 10 bar) was discussed. A very high removal of sulphur content of more than 90% was demonstrated. The process is easy to operate, essentially works at ambient conditions and the ratio of aqueous to organic phase can be easily adjusted to maximise sulphur removal. Experimental studies were also carried out using commercial diesel as a solvent and the results substantiate similar high sulphur removal. A comparison of the two cavitating devices- one with a linear flow and one using vortex flow for effecting pressure drop and cavitation indicates similar trends in terms of sulphur removal behaviour. The developed process is expected to provide an attractive environmental engineering alternative for deep desulphurization of transportation fuels.

Keywords: cavitation, petroleum, separation, sulphur removal

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Authors: O. Yu Shchelkova, E. B. Usmanova

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Introduction: Last decades scientific research of quality of life (QoL) is developing fast worldwide. QoL concept pays attention to emotional experience of disease in patients, particularly to personal sense of possibility to satisfy actual needs and possibility of full social functioning in spite of disease limitations. QoL in oncological patients is studied intensively. Nevertheless, the issue of QoL in patients with bone tumors focused on psychological factors of QoL and relation to disease impact on QoL is not discussed. The aim of the study was to reveal the basic aspects and personality factors of QoL in patients with bone tumor. Results: Study participants were 139 patients with bone tumors. The diagnoses were osteosarcoma (n=42), giant cell tumor (n=32), chondrosarcoma (n=32), Ewing sarcoma (n=10) and bone metastases (n=23). The study revealed that patients with bone metastases assess their health significantly worse than other patients. Besides patients with osteosarcoma evaluate their general health higher than patients with giant cell tumors. Social functioning in patients with chondrosarcoma is higher than in patients with bone metastases and patients with giant cell tumor. Patients with chondrosarcoma have higher physical functioning and less restricted in daily activities than patients with bone metastases. Patients with bone metastases characterize their pain as more widespread than patients with primary bone tumors and have more functional restrictions due to bone incision. Moreover, the study revealed personality significant influence on QoL related to bone tumors. Such characteristics in structure of personality as high degree of self-consciousness, personal resources, cooperation and disposition to positive reappraisal in difficult situation correspond to higher QoL. Otherwise low personal resources and slight problem solving behaviour, low degree of self-consciousness and high social dependence correspond to decrease of QoL in patients with bone tumors. Conclusion: Patients with bone metastasis have lower QoL compared to patients with primary bone tumors. Patients with giant cell tumor have the worth quality of life among patients with primary bone tumors. Furthermore, the results revealed differences in QoL parameters associated with personality characteristics in patients with bone tumors. Such psychological factors as future goals, interest in life and emotional saturation, besides high degree of personal resources and cooperation influence on increasing QoL in patients with bone tumors.

Keywords: quality of life, psychological factors, bone tumor, personality

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Authors: Christian Lauter, Corin Reuter, Shuang Wu, Thomas Troester

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Lightweight construction became more and more important over the last decades in several applications, e.g. in the automotive or aircraft sector. This is the result of economic and ecological constraints on the one hand and increasing safety and comfort requirements on the other hand. In the field of lightweight design, different approaches are used due to specific requirements towards the technical systems. The use of endless carbon fiber reinforced plastics (CFRP) offers the largest weight saving potential of sometimes more than 50% compared to conventional metal-constructions. However, there are very limited industrial applications because of the cost-intensive manufacturing of the fibers and production technologies. Other disadvantages of pure CFRP-structures affect the quality control or the damage resistance. One approach to meet these challenges is hybrid materials. This means CFRP and sheet metal are combined on a material level. Therefore, new opportunities for innovative process routes are realizable. Hybrid lightweight design results in lower costs due to an optimized material utilization and the possibility to integrate the structures in already existing production processes of automobile manufacturers. In recent and current research, the advantages of two-layered hybrid materials have been pointed out, i.e. the possibility to realize structures with tailored mechanical properties or to divide the curing cycle of the epoxy resin into two steps. Current research work at the Chair for Automotive Lightweight Design (LiA) at the Paderborn University focusses on production processes for fiber-metal-laminates. The aim of this work is the development and qualification of a large-scale production process for high-performance fiber-metal-laminates (FML) for industrial applications in the automotive or aircraft sector. Therefore, the prepreg-press-technology is used, in which pre-impregnated carbon fibers and sheet metals are formed and cured in a closed, heated mold. The investigations focus e.g. on the realization of short process chains and cycle times, on the reduction of time-consuming manual process steps, and the reduction of material costs. This paper gives an overview over the considerable steps of the production process in the beginning. Afterwards experimental results are discussed. This part concentrates on the influence of different process parameters on the mechanical properties, the laminate quality and the identification of process limits. Concluding the advantages of this technology compared to conventional FML-production-processes and other lightweight design approaches are carried out.

Keywords: composite material, fiber-metal-laminate, lightweight construction, prepreg-press-technology, large-series production

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Authors: Daniel R. Zeh, Michelle R. Heupel, Mark Hamann, Rhondda Jones, Colin J. Limpus, Helene Marsh

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Marine mammals live in an environment with water temperatures nearly always lower than the mammalian core body temperature of 35 - 38°C. Marine mammals can lose heat at high rates and have evolved a range of adaptations to minimise heat loss. Our project tracked dugongs to examine if there was a discoverable relationship between the animals’ movements and the temperature of their environment that might suggest behavioural thermoregulation. Twenty-nine dugongs were fitted with acoustic and satellite/GPS transmitters in 2012, 2013 and 2014 in Moreton Bay Queensland at the high latitude limit of the species’ winter range in eastern Australia on 30 occasions (one animal was tagged twice). All 22 animals that stayed in the area and had functional transmitters made at least one (and up to 66) return trip(s) to the warmer oceanic waters outside the bay where seagrass is unavailable. Individual dugongs went in and out of the bay in synchrony with the tides and typically spent about 6 hours in the oceanic water. There was a diel pattern in the movements: 85% of outgoing trips occurred between midnight and noon. There were significant individual differences, but the likelihood of a dugong leaving the bay was independent of body length or sex. In Quarter 2 (April – June), the odds of a dugong making a trip increased by about 40% for each 1°C increase in the temperature difference between the bay and the warmer adjacent oceanic waters. In Quarter 3, the odds of making a trip were lower when the outside –inside bay temperature differences were small or negative but increased by a factor of up to 2.12 for each 1°C difference in outside – inside temperatures. In Quarter 4, the odds of making a trip were higher when it was cooler outside the bay and decreased by a factor of nearly 0.5 for each 1°C difference in outside – inside bay temperatures. The activity spaces of the dugongs generally declined as winter progressed suggesting a change in the cost-effectiveness of moving outside the bay. Our analysis suggests that dugongs can thermoregulate their core temperature through the behaviour of moving to water having more favourable temperature.

Keywords: acoustic, behavioral thermoregulation, dugongs, movements, satellite, telemetry, quick fix GPS

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Authors: Wisam H. Muragaa, Kamaruzzaman Seman, Mohd Fadzli Marhusin

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Software Defined Networking (SDN) is a new norm of networks. It is designed to facilitate the way of managing, measuring, debugging and controlling the network dynamically, and to make it suitable for the modern applications. Generally, measurement methods can be divided into two categories: Active and passive methods. Active measurement method is employed to inject test packets into the network in order to monitor their behaviour (ping tool as an example). Meanwhile the passive measurement method is used to monitor the traffic for the purpose of deriving measurement values. The measurement methods, both active and passive, are useful for the collection of traffic statistics, and monitoring of the network traffic. Although there has been a work focusing on measuring traffic statistics in SDN environment, it was only meant for measuring packets and bytes rates for non-web traffic. In this study, a feasible method will be designed to measure the number of packets and bytes in a certain time, and facilitate obtaining statistics for both web traffic and non-web traffic. Web traffic refers to HTTP requests that use application layer; while non-web traffic refers to ICMP and TCP requests. Thus, this work is going to be more comprehensive than previous works. With a developed module on POX OpenFlow controller, information will be collected from each active flow in the OpenFlow switch, and presented on Command Line Interface (CLI) and wireshark interface. Obviously, statistics that will be displayed on CLI and on wireshark interfaces include type of protocol, number of bytes and number of packets, among others. Besides, this module will show the number of flows added to the switch whenever traffic is generated from and to hosts in the same statistics list. In order to carry out this work effectively, our Python module will send a statistics request message to the switch requesting its current ports and flows statistics in every five seconds; while the switch will reply with the required information in a message called statistics reply message. Thus, POX controller will be notified and updated with any changes could happen in the entire network in a very short time. Therefore, our aim of this study is to prepare a list for the important statistics elements that are collected from the whole network, to be used for any further researches; particularly, those that are dealing with the detection of the network attacks that cause a sudden rise in the number of packets and bytes like Distributed Denial of Service (DDoS).

Keywords: mininet, OpenFlow, POX controller, SDN

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Authors: Yusuf Yasa, Erkan Mese

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This paper investigates the thermal issue of permanent magnet synchronous generator which is frequently used in direct drive gearless small-scale wind turbine applications. Permanent magnet synchronous generator (PMSG) is designed with 2.5 kW continuous and 6 kW peak power. Then considering generator geometry, mechanical design of wind turbine is performed. Thermal analysis and optimization is carried out considering all wind turbine components to reach realistic results. These issue is extremely important in research and development(R&D) process for wind turbine applications.

Keywords: direct drive, gearless wind turbine, permanent magnet synchronous generator (PMSG), small-scale wind turbine, thermal management

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Authors: Stefano Federici, Alessandro Lepri, Antonella Carrera

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Kessler and McKenna in the seventies, and recently Federici and Lepri investigated how an individual attributes gender to a person. By administering nudes of human figures, the scholars have found that the penis more than the vagina and the male sexual characteristics more than the female ones are significantly more salient in the gender attribution process. Federici and Lepri suggested that the asymmetrical salience of sexual characteristics is attributable to evolved decision-making processes for the solution of gender attribution problems to avoid the greatest danger of an (angry) adult male. The present study has observed the behaviour of 60 children, aged between 3 and 6 years, and their parents verifying whether the child gender attribution mechanisms are permeable to cultural stereotypes. The participating children were asked to make a male or a female on a tablet by combining 12 human physical characteristics (long hair, short hair, wide hips, narrow hips, breasts, flat chest, body hair, hairless body, penis, vagina, male face, and female face) and four cloths (male t-shirt, female t-shirt, pants, and skirt) by superimposing one or more of them on a sexually neutral manikin. On the tablet was installed an App, created by authors, to replicate the Kessler and McKenna and Federici and Lepri previous studies. One of the parents of each of the participating children was asked to make a male or a female using the same apparatus used by children. In addition, the participating parents were asked to complete a test, as proposed by Federici and Lepri in their previous study, to compare adult and child processes of gender attribution. The results suggested that children are affected both by evolved mechanisms as adults were (e.g., taking less time to make a male than a female, using the penis more often than the vagina), and by cultural modeling of parental and environmental gender stereotypes (e.g., the genitals were often covered with pants in case the delivery was to make a male and a skirt in the case was to make a female).

Keywords: biological sex, cognitive biases, cultural modeling, gender attribution, evolved decision-making processes

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Authors: Nidal H. Abu-Zahra, Parisa Khoshnoud, Murtatha Jamel, Subhashini Gunashekar

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PVC foam-fly ash composites (PVC-FA) are characterized for their structural, morphological, mechanical and thermal properties. The tensile strength of the composites increased modestly with higher fly ash loading, while there was a significant increase in the elastic modulus for the same composites. On the other hand, a decrease in elongation at UTS was observed upon increasing fly ash content due to increased rigidity of the composites. Similarly, the flexural modulus increased as the fly ash loading increased, where the composites containing 25 phr fly ash showed the highest flexural strength. Thermal properties of PVC-fly ash composites were determined by Thermo Gravimetric Analysis (TGA). The micro structural properties were studied by Scanning Electron Microscopy (SEM). SEM results confirm that fly ash particles were mechanically interlocked in PVC matrix with good inter facial interaction with the matrix. Particle agglomeration and debonding was observed in samples containing higher amounts of fly ash.

Keywords: PVC foam, polyvinyl chloride, rigid PVC, fly ash composites, polymer composites

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Authors: Allal Bedlaoui, Hamid Boutoutaou

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Due to its superior economics, shrink-fit assembly is one of the best mechanical assembly methods. There are simply two components, the axis and hub. It is used in many different industries, including the production of trains, cars, and airplanes. The outer radius of the inner cylinder must be greater than the inner radius of the outer cylinder for this operation; this difference is referred to as the "interference" between the two cylinders. There are three ways to accomplish this: heating the outer cylinder to cause it to expand; cooling the cylinder's inside to cause it to contract; and third, finishing the fitting under a press. At the intersection of the two matched parts, a contact pressure and friction force are generated. We consider interference and form defects in this article because they prevent the connection between the axis and the hub from having a perfect form surface and because we will be looking at how they affect the assembly. Numerical simulation is used to ascertain if interference and form defects have a beneficial or negative influence in the distribution of stresses, assembly resistance, and plasticity.

Keywords: shrink-fit, interference, form defect, plasticity, extraction force

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Authors: Paulos Meles Yihdego

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To address the environmental impact of the cement industry and road building waste, the use of chemical stabilizers in conjunction with recycled asphalt and cement components was investigated. The silica-based chemical stabilizers and their potential effects on the base layer stabilized by cement are discussed in this paper. Strength, moisture compaction interaction, and microstructural characteristics are all examined. According to the outcome, using this stabilizer has improved the mechanical properties. The inclusion of chemical stabilizers in the combination, which is responsible for the mixture's improved strength, raised the intensity of the C-S-H (Calcium Silicate Hydrate) gel, according to a microstructural study. The design was demonstrated to be durable by the little ettringites found in the later phases. The application of this stabilizer ensures a strong, eco-friendly, durable base layer.

Keywords: ettringites, microstructure analysis, durability properties, cement stabilized base

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Authors: Mohamed Abo El Nasr, Mohamed Shoeib, Abdelhamid Abdelkhalik, Amro Serag

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Background: Early assessment of severity of chest trauma, either blunt or penetrating is of critical importance in prediction of patient outcome. Different trauma scoring systems are widely available and are based on anatomical or physiological parameters to expect patient morbidity or mortality. Up till now, there is no ideal, universally accepted trauma score that could be applied in all trauma centers and is suitable for assessment of severity of chest trauma patients. Aim: Our aim was to compare various trauma scoring systems regarding their predictability of morbidity and mortality in chest trauma patients. Patients and Methods: This study was a prospective study including 400 patients with chest trauma who were managed at Tanta University Emergency Hospital, Egypt during a period of 2 years (March 2014 until March 2016). The patients were divided into 2 groups according to the mode of trauma: blunt or penetrating. The collected data included age, sex, hemodynamic status on admission, intrathoracic injuries, and associated extra-thoracic injuries. The patients outcome including mortality, need of thoracotomy, need for ICU admission, need for mechanical ventilation, length of hospital stay and the development of acute respiratory distress syndrome were also recorded. The relevant data were used to calculate the following trauma scores: 1. Anatomical scores including abbreviated injury scale (AIS), Injury severity score (ISS), New injury severity score (NISS) and Chest wall injury scale (CWIS). 2. Physiological scores including revised trauma score (RTS), Acute physiology and chronic health evaluation II (APACHE II) score. 3. Combined score including Trauma and injury severity score (TRISS ) and 4. Chest-Specific score Thoracic trauma severity score (TTSS). All these scores were analyzed statistically to detect their sensitivity, specificity and compared regarding their predictive power of mortality and morbidity in blunt and penetrating chest trauma patients. Results: The incidence of mortality was 3.75% (15/400). Eleven patients (11/230) died in blunt chest trauma group, while (4/170) patients died in penetrating trauma group. The mortality rate increased more than three folds to reach 13% (13/100) in patients with severe chest trauma (ISS of >16). The physiological scores APACHE II and RTS had the highest predictive value for mortality in both blunt and penetrating chest injuries. The physiological score APACHE II followed by the combined score TRISS were more predictive for intensive care admission in penetrating injuries while RTS was more predictive in blunt trauma. Also, RTS had a higher predictive value for expectation of need for mechanical ventilation followed by the combined score TRISS. APACHE II score was more predictive for the need of thoracotomy in penetrating injuries and the Chest-Specific score TTSS was higher in blunt injuries. The anatomical score ISS and TTSS score were more predictive for prolonged hospital stay in penetrating and blunt injuries respectively. Conclusion: Trauma scores including physiological parameters have a higher predictive power for mortality in both blunt and penetrating chest trauma. They are more suitable for assessment of injury severity and prediction of patients outcome.

Keywords: chest trauma, trauma scores, blunt injuries, penetrating injuries

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Authors: Houssem Ayari

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Sheet molding compounds (SMC) are high strength thermoset moulding materials reinforced with glass treated with thermocompression. SMC composites combine fibreglass resins and polyester/phenolic/vinyl and unsaturated acrylic to produce a high strength moulding compound. These materials are usually formulated to meet the performance requirements of the moulding part. In addition, the vinyl ester resins used in the new advanced SMC systems (A-SMC) have many desirable features, including mechanical properties comparable to epoxy, excellent chemical resistance and tensile resistance, and cost competitiveness. In this paper, a proposed model is used to take into account the Young modulus evolutions of advanced SMC systems (A-SMC) composite under fatigue tests. The proposed model and the used approach are in good agreement with the experimental results.

Keywords: composites SFRC, damage, fatigue, Mori-Tanaka

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Authors: Pronab Ganguly, Ahmed A. Moustafa

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Holistic management of schizophrenia involves mainstream pharmacological intervention, complimentary medicine intervention, therapeutic intervention and other psychosocial factors such as accommodation, education, job training, employment, relationship, friendship, exercise, overall well-being, smoking, substance abuse, suicide prevention, stigmatisation, recreation, entertainment, violent behaviour, arrangement of public trusteeship and guardianship, day-day-living skill, integration with community, and management of overweight due to medications and other health complications related to medications amongst others. Our review shows that there is no integrated survey by combining all these factors. An international web-based survey was conducted to evaluate the significance of all these factors and present them in a unified manner. It is believed this investigation will contribute positively towards holistic management of schizophrenia. There will be two surveys. In the pharmacological intervention survey, five popular drugs for schizophrenia will be chosen and their efficacy as well as harmful side effects will be evaluated on a scale of 0 -10. This survey will be done by psychiatrists. In the second survey, each element of therapeutic intervention and psychosocial factors will be evaluated according to their significance on a scale of 0 - 10. This survey will be done by care givers, psychologists, case managers and case workers. For the first survey, professional bodies of psychiatrists in English speaking countries will be contacted to request them to ask their members to participate in the survey. For the second survey, professional bodies of clinical psychologist and care givers in English speaking countries will be contacted to request them to ask their members to participate in the survey. Additionally, for both the surveys, relevant professionals will be contacted through personal contact networks. For both the surveys, mean, mode, median, standard deviation and net promoter score will be calculated for each factor and then presented in a statistically significant manner. Subsequently each factor will be ranked according to their statistical significance. Additionally, country specific variation will be highlighted to identify the variation pattern. The results of these surveys will identify the relative significance of each type of pharmacological intervention, each type of therapeutic intervention and each type of psychosocial factor. The determination of this relative importance will definitely contribute to the improvement in quality of life for individuals with schizophrenia.

Keywords: schizophrenia, holistic management, antipsychotics, quality of life

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Authors: S. Ansari Sadrabadi, G. H. Rahimi

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In this paper, thick walled Cylindrical tanks or tubes made of functionally graded material under internal pressure and temperature gradient are studied. Material parameters have been considered as power functions. They play important role in the elastoplastic behavior of these materials. To clarify their role, different materials with different parameters have been used under temperature gradient. Finally, their effect and loading effect have been determined in first yield point. Also, the important role of temperature gradient was also shown. At the end the study has been results obtained from changes in the elastic modulus and yield stress. Also special attention is also given to the effects of this internal pressure and temperature gradient in the creation of tensile and compressive stresses.

Keywords: FGM, cylindrical pressure tubes, small deformation theory, yield onset, thermal loading

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Authors: Karel Frana, Sylvio Simon

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The objective of the paper is a numerical study of heat transfer between perforated metal plates and the surrounding air flows. Different perforation structures can nowadays be found in various industrial products. Besides improving the mechanical properties, the perforations can intensify the heat transfer as well. The heat transfer coefficient depends on a wide range of parameters such as type of perforation, size, shape, flow properties of the surrounding air etc. The paper was focused on three different perforation structures which have been investigated from the point of the view of the production in the previous studies. To determine the heat coefficients and the Nusselt numbers, the numerical simulation approach was adopted. The calculations were performed using the OpenFOAM software. The three-dimensional, unstable, turbulent and incompressible air flow around the perforated surface metal plate was considered.

Keywords: perforations, convective heat transfers, turbulent flows, numerical simulations

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Authors: Hamed Khosravi, Reza Eslami-Farsani

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Increased interest in lightweight and efficient structural components has created the need for selecting materials with improved mechanical properties. To do so, composite materials are being widely used in many applications, due to durability, high strength and modulus, and low weight. Among the various composite structures, grid-stiffened structures are extensively considered in various aerospace and aircraft applications, because of higher specific strength and stiffness, higher impact resistance, superior load-bearing capacity, easy to repair, and excellent energy absorption capability. Although there are a good number of publications on the design aspects and fabrication of grid structures, little systematic work has been reported on their material modification to improve their properties, to our knowledge. Therefore, the aim of this research is to study the reinforcing effect of silica nanoparticles on the flexural properties of epoxy/E-glass isogrid panels under three-point bending test. Samples containing 0, 1, 3, and 5 wt.% of the silica nanoparticles, with 44 and 48 vol.% of the glass fibers in the ribs and skin components respectively, were fabricated by using a manual filament winding method. Ultrasonic and mechanical routes were employed to disperse the nanoparticles within the epoxy resin. To fabricate the ribs, the unidirectional fiber rovings were impregnated with the matrix mixture (epoxy + nanoparticles) and then laid up into the grooves of a silicone mold layer-by-layer. At once, four plies of woven fabrics, after impregnating into the same matrix mixture, were layered on the top of the ribs to produce the skin part. In order to conduct the ultimate curing and to achieve the maximum strength, the samples were tested after 7 days of holding at room temperature. According to load-displacement graphs, the bellow trend was observed for all of the samples when loaded from the skin side; following an initial linear region and reaching a load peak, the curve was abruptly dropped and then showed a typical absorbed energy region. It would be worth mentioning that in these structures, a considerable energy absorption was observed after the primary failure related to the load peak. The results showed that the flexural properties of the nanocomposite samples were always higher than those of the nanoparticle-free sample. The maximum enhancement in flexural maximum load and energy absorption was found to be for the incorporation of 3 wt.% of the nanoparticles. Furthermore, the flexural stiffness was continually increased by increasing the silica loading. In conclusion, this study suggested that the addition of nanoparticles is a promising method to improve the flexural properties of grid-stiffened fibrous composite structures.

Keywords: grid-stiffened composite structures, nanocomposite, three point flexural test , energy absorption

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Authors: Mandip Singh

Abstract:

Quantum entanglement plays a fundamental role in our understanding of counter-intuitive aspects of quantum reality. If classical physics is an approximation of quantum physics, then quantum entanglement should persist at a macroscopic scale. In this paper, a thought experiment is presented where a free falling spin polarized Bose-Einstein condensate interacts with a quantum superimposed magnetic field of nonzero gradient. In contrast to the semiclassical Stern-Gerlach experiment, the magnetic field and the spin degrees of freedom both are considered to be quantum mechanical in a generalized scenario. As a consequence, a Bose-Einstein condensate can be prepared at distinct locations in space in a sense of quantum superposition. In addition, the generation of Schrodinger-cat like quantum states shall be presented.

Keywords: Schrodinger-cat quantum states, macroscopic entanglement, macroscopic quantum fields, foundations of quantum physics

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Authors: Natia Jalagonia, Jimsher Maisuradze, Karlo Barbakadze, Tinatin Kuchukhidze

Abstract:

At present intensive scientific researches of ceramics, cermets and metal alloys have been conducted for improving materials physical-mechanical characteristics. In purpose of increasing impact strength of ceramics based on alumina, simple method of graphene homogenization was developed. Homogeneous distribution of graphene (homogenization) in pressing composite became possible through the connection of functional groups of graphene oxide (-OH, -COOH, -O-O- and others) and alumina superficial OH groups with aluminum organic compounds. These two components connect with each other with -O-Al–O- bonds, and by their thermal treatment (300–500°C), graphene and alumina phase are transformed. Thus, choosing of aluminum organic compounds for modification is stipulated by the following opinion: aluminum organic compounds fragments fixed on graphene and alumina finally are transformed into an integral part of the matrix. By using of other elements as modifier on the matrix surface (Al2O3) other phases are transformed, which change sharply physical-mechanical properties of ceramic composites, for this reason, effect caused by the inclusion of graphene will be unknown. Fixing graphene fragments on alumina surface by alumoorganic compounds result in new type graphene-alumina complex, in which these two components are connected by C-O-Al bonds. Part of carbon atoms in graphene oxide are in sp3 hybrid state, so functional groups (-OH, -COOH) are located on both sides of graphene oxide layer. Aluminum organic compound reacts with graphene oxide at the room temperature, and modified graphene oxide is obtained: R2Al-O-[graphene]–COOAlR2. Remaining Al–C bonds also reacts rapidly with surface OH groups of alumina. In a result of these process, pressing powdery composite [Al2O3]-O-Al-O-[graphene]–COO–Al–O–[Al2O3] is obtained. For the purpose, graphene oxide suspension in dry toluene have added alumoorganic compound Al(iC4H9)3 in toluene with equimolecular ratio. Obtained suspension has put in the flask and removed solution in a rotary evaporate presence nitrogen atmosphere. Obtained powdery have been researched and used to consolidation of ceramic materials based on alumina. Ceramic composites are obtained in high temperature vacuum furnace with different temperature and pressure conditions. Received ceramics do not have open pores and their density reaches 99.5 % of TD. During the work, the following devices have been used: High temperature vacuum furnace OXY-GON Industries Inc (USA), device of spark-plasma synthesis, induction furnace, Electronic Scanning Microscopes Nikon Eclipse LV 150, Optical Microscope NMM-800TRF, Planetary mill Pulverisette 7 premium line, Shimadzu Dynamic Ultra Micro Hardness Tester DUH-211S, Analysette 12 Dynasizer and others.

Keywords: graphene oxide, alumo-organic, ceramic

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Authors: Amir H. Alavi, Kaveh Barri, Qianyun Zhang

Abstract:

This study presents a new generation of lightweight and mechanically tunable structural composites with sensing and energy harvesting functionalities. This goal is achieved by integrating metamaterial and triboelectric energy harvesting concepts. Proof-of-concept polymeric beam prototypes are fabricated using 3D printing methods based on the proposed concept. Experiments and theoretical analyses are conducted to quantitatively investigate the mechanical and electrical properties of the designed multifunctional beams. The results show that these integrated structural elements can serve as nanogenerators and distributed sensing mediums without a need to incorporating any external sensing modules and electronics. The feasibility of design self-sensing and self-powering structural elements at multiscale for next generation infrastructure systems is further discussed.

Keywords: multifunctional structures, composites, metamaterial, triboelectric nanogenerator, sensors, structural health monitoring, energy harvesting

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Authors: Qiong Rao, Xiongqi Peng

Abstract:

In this work, multi-walled carbon nanotubes (MWCNTs) and graphene nanoplates (GNPs) were dispersed into epoxy adhesive to investigate their synergy effects on the shear properties, mode I and mode II fracture toughness of unidirectional composite bonded joints. Testing results showed that the incorporation of MWCNTs and GNPs significantly improved the shear strength, the mode I and mode II fracture toughness by 36.6%, 45% and 286%, respectively. In addition, the fracture surfaces of the bonding area as well as the toughening mechanism of nanofillers were analyzed. Finally, a nonlinear cohesive/friction coupled model for delamination analysis of adhesive layer under shear and normal compression loadings was proposed and implemented in ABAQUS/Explicit via user subroutine VUMAT.

Keywords: nanofillers, adhesive joints, fracture toughness, cohesive zone model

Procedia PDF Downloads 118

Authors: Leto Leandra, Guaitini Caterina, Agosti Anna, Del Vecchio Lorenzo, Guarrasi Valeria, Cirlini Martina, Chiancone Benedetta

Abstract:

To the best of our knowledge, this study represents the first attempt to investigate the in vitro germination response of Rhus coriaria L., and its sprout chemical characterization. Rhus coriaria L., a species belonging to the Anacardiaceae family, is commonly called "sumac" and is cultivated, in different countries of the Mediterranean and the Middle East regions, to produce a spice with a sour taste, obtained from its dried and ground fruits. Moreover, since ancient times, many beneficial properties have been attributed to this plant that has been used, in the traditional medicine of several Asian countries, against various diseases, including liver and intestinal pathologies, ulcers and various inflammatory states. In the recent past, sumac was cultivated in the Southern regions of Italy to treat leather, but its cultivation was abandoned, and currently, sumac plants grow spontaneously in marginal areas. Recently, in Italy, the interest in this species has been growing again, thanks to its numerous properties; thus, it becomes imperative to deepen the knowledge of this plant. In this study, in order to set up an efficient in vitro seed germination protocol, sumac seeds collected from spontaneous plants grown in Sicily, an island in the South of Italy, were, firstly, subjected to different treatments, scarification (mechanical, physical and chemical), cold stratification and imbibition, to break their physical and physiological dormancy, then, treated seeds were in vitro cultured on media with different gibberellic acid (GA3) concentrations. Results showed that, without any treatment, only 5% of in vitro sown seeds germinated, while the germination percentage increased up to 19% after the mechanical scarification. A further significative improvement of germination percentages was recorded after the physical scarification, with (40.5%) or without (36.5%) 8 weeks of cold stratification, especially when seeds were sown on gibberellin enriched cultured media. Vitro-derived sumac sprouts, at different developmental stages, were chemically characterized, in terms of polyphenol and tannin content, as well as for their antioxidant activity, to evaluate this matrix as a potential novel food or as a source of bioactive compounds. Results evidenced how more developed sumac sprouts and, above all, their leaves are a wealthy source of polyphenols (78.4 GAE/g SS) and tannins (21.9 mg GAE/g SS), with marked antioxidant activity. The outcomes of this study will be of support the nursery sector and sumac growers in obtaining a higher number of plants in a shorter time; moreover, the sprout chemical characterization will contribute to the process of considering this matrix as a new source of bioactive compounds and tannins to be used in food and non-food sectors.

Keywords: bioactive compounds, germination pre-treatments, rhus coriaria l., tissue culture

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Authors: Leto Leandra, Guaitini Caterina, Agosti Anna, Del Vecchio Lorenzo, Guarrasi Valeria, Cirlini Martina, Chiancone Benedetta

Abstract:

To the best of our knowledge, this study represents the first attempt to investigate the in vitro germination response of Rhus coriaria L. and its sprout chemical characterization. Rhus coriaria L., a species belonging to the Anacardiaceae family, is commonly called "sumac” and is cultivated, in different countries of the Mediterranean and the Middle East regions, to produce a spice with a sour taste, obtained from its dried and ground fruits. Moreover, since ancient times, many beneficial properties have been attributed to this plant that has been used, in the traditional medicine of several Asian countries, against various diseases, including liver and intestinal pathologies, ulcers, and various inflammatory states. In the recent past, sumac was cultivated in the Southern regions of Italy to treat leather, but its cultivation was abandoned, and currently, sumac plants grow spontaneously in marginal areas. Recently, in Italy, the interest in this species has been growing again, thanks to its numerous properties; thus, it becomes imperative to deepen the knowledge of this plant. In this study, in order to set up an efficient in vitro seed germination protocol, sumac seeds collected from spontaneous plants grown in Sicily, an island in the South of Italy, were, firstly, subjected to different treatments, scarification (mechanical, physical and chemical), cold stratification and imbibition, to break their physical and physiological dormancy, then, treated seeds were in vitro cultured on media with different gibberellic acid (GA3) concentrations. Results showed that, without any treatment, only 5% of in vitro sown seeds germinated, while the germination percentage increased up to 19% after the mechanical scarification. A further significative improvement of germination percentages was recorded after the physical scarification, with (40.5%) or without (36.5%) 8 weeks of cold stratification, especially when seeds were sown on gibberellin enriched cultured media. Vitro-derived sumac sprouts, at different developmental stages, were chemically characterized, in terms of polyphenol and tannin content, as well as for their antioxidant activity, to evaluate this matrix as a potential novel food or as a source of bioactive compounds. Results evidenced how more developed sumac sprouts and, above all, their leaves are a wealthy source of polyphenols (78.4 GAE/g SS) and tannins (21.9 mg GAE/g SS), with marked antioxidant activity. The outcomes of this study will be of support the nursery sector and sumac growers in obtaining a higher number of plants in a shorter time; moreover, the sprout chemical characterization will contribute to the process of considering this matrix as a new source of bioactive compounds and tannins to be used in food and non-food sectors.

Keywords: bioactive compounds, germination pre-treatments, rhus coriaria l., tissue culture

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Authors: Long Zhang, Ian Hampson, Loretta O' Donnell

Abstract:

Practitioners in various industries, especially in the finance industry that conventionally benefit from financial capital and resources, appear to be increasingly aware of the importance of human capital resources (HCR) after the 2008 Global Financial Crisis. Scholars from diverse fields have conducted extensive and fruitful research on HCR within their own disciplines. This review suggests that the mainstream of pure quantitative research alone is insufficient to provide precise or comprehensive understanding of HCR. The complex relationships and interactions in HCR call for more integrative and cross-disciplinary research to more holistically understand complex and intricate HCRs. The complex nature of HCR requires deep qualitative exploration based on in-depth data to capture the everydayness of organizational activities and to register its individuality and variety. Despite previous efforts, a systematic and holistic integration of HCR research among multiple disciplines is lacking. Using a retrospective analysis of articles published in the field of economics, finance and management, including psychology, human resources management (HRM), organizational behaviour (OB), industrial and organizational psychology (I-O psychology), organizational theory, and strategy literatures, this study summaries and compares the major perspectives, theories, and findings on HCR research. A careful examination of the progress of the debates of HCR definitions and measurements in distinct disciplines enables an identification of the limitations and gaps in existing research. It enables an analysis of the interplay of these concepts, as well as that of the related concepts of intellectual capital, social capital, and Chinese guanxi, and how they provide a broader perspective on the HCR-related influences on firms’ competitive advantage. The study also introduces the themes of Environmental, Social and Governance, or ESG based investing, as the burgeoning body of ESG studies illustrates the rising importance of human and non-financial capital in investment process. The ESG literature locates HCR into a broader research context of the value of non-financial capital in explaining firm performance. The study concludes with a discussion of new directions for future research that may help advance our knowledge of HCR.

Keywords: human capital resources, social capital, Chinese guanxi, human resources management

Procedia PDF Downloads 338