Search results for: scanning path

Authors: Saba Didarataee, Abbas Ali Khodadadi, Yadollah Mortazavi, Fatemeh Mousavi

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Photocatalytic water splitting is one of the most attractive alternative methods for hydrogen evolution. A variety of nanoparticle engineering techniques were introduced to improve the activity of semiconductor photocatalysts. Among these methods, heterojunction formation is an appealing method due to its ability to effectively preventing electron-hole recombination and improving photocatalytic activity. Reaching an optimal ratio of the two target semiconductors for the formation of heterojunctions is still an open question. Considering environmental issues as well as the cost and availability, ZnS and ZnO are frequently studied as potential choices. In this study, first, the ZnS nanoparticle was synthesized in a hydrothermal process; the formation of ZnS nanorods with a diameter of 14-30 nm was confirmed by field emission scanning electron microscope (FESEM). Then two different methods, partial oxidation and chemical precipitation were employed to construct ZnS/ZnO core-shell heterojunction. X-ray diffraction (XRD), BET, and diffuse reflectance spectroscopy (DRS) analysis were carried out to determine crystallite phase, surface area, and bandgap of photocatalysts. Furthermore, the temperature of oxidation was specified by a temperature programmed oxidation (TPO) and was fixed at 510℃, at which mild oxidation occurred. The bandgap was calculated by the Kubelka-Munk method and decreased by increasing oxide content from 3.53 (pure ZnS) to 3.18 (pure ZnO). The optimal samples were determined by testing the photocatalytic activity of hydrogen evolution in a quartz photoreactor with side irradiation of UVC lamps with a wavelength of 254 nm. In both procedures, it was observed that the photocatalytic activity of the ZnS/ZnO composite was sensibly higher than the pure ZnS and ZnO, which is attributed to forming a type-II heterostructure. The best ratio of oxide to sulfide was 0.24 and 0.37 in partial oxidation and chemical precipitation, respectively. The highest hydrogen evolution was 1081 µmol/gr.h, gained from partial oxidizing of ZnS nanoparticles at 510℃ for 30 minutes.

Keywords: heterostructure, hydrogen, partial oxidation, photocatalyst, water splitting, ZnS

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Authors: Katarzyna Wal, Wojciech Stawiński, Piotr Rutkowski

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The scientific community is paying more and more attention to the problem of air pollution. Carbon dioxide is classified as one of the most harmful gases. Its emissions are generated during fossil fuel burning, waste management, and combustion and are responsible for global warming. Clay minerals constitute a group of promising materials for the role of adsorbents. They are composed of two types of phyllosilicate sheets: tetrahedral and octahedral, which form 1:1 or 2:1 structures. Vermiculite is one of their best-known representative, which can be used as an adsorbent from water and gaseous phase. The aim of the presented work was carbon dioxide adsorption on vermiculite. Acid-activated samples (W_NO3_x) were prepared by acid treatment with different concentrations of nitric acid (1, 2, 3, 4 mol L⁻¹). Vermiculite was subjected to modification in order to increase its porosity and adsorption properties. The prepared adsorbents were characterized using the BET-specific surface area analysis, thermogravimetry (TG), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Applied modifications significantly increase the specific surface area from 78,21 m² g⁻¹ for the unmodified sample (W_REF) to 536 m² g-1 for W_NO3_4. Obtained results showed that acid treatment tunes the material’s functional properties by increasing the contact surface and generating more active sites in its structure. The adsorption performance in terms carbon dioxide adsorption capacities follows the order of W_REF (25.91 mg g⁻¹) < W_NO3_1 (38.54 mg g⁻¹) < W_NO3_2 (44.03 mg g⁻¹) W_NO3_4 (67.51 mg g⁻¹) < W_NO3_3 (70.48 mg g⁻¹). Acid activation significantly improved the carbon dioxide adsorption properties of modified samples compared to raw material. These results demonstrate that vermiculite-based samples have the potential to be used as effective CO₂ adsorbents. Furthermore, acid treatment is a promising technique for improving the adsorption properties of clay minerals.

Keywords: adsorption, adsorbent, clay minerals, air pollution, environment

Procedia PDF Downloads 135

Authors: Francesca Alemanno

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As a complex socio-spatial phenomenon, migration is a practice that also contains a strong imaginative component with respect to the place that, through displacement, one person wants to reach. Every migrant has undertaken his journey having in his mind an image of the displacement he was about to make, of its implications and finally, of the place or city in which he was or would have liked to land. Often, however, the imaginary that has come to build before departure does not fully correspond to the reality of landing; this discrepancy, which can be more or less wide, plays an important role in the relationship that is established with the territory and in the evolution, therefore, of the city itself. In this sense, therefore, the clash that occurs between the imagined and the real is one of the factors that can contribute to making the entry of a migrant into new territory as critical as it can be. Starting from this perspective, the experiences of people who derive from a migratory context and who, over time, manage to create a bond with the land of reception, are taken into account as stories of resistance as they are necessarily charged with a force that is capable of driving difficult and articulated processes of change. The phenomenon of migrant entrepreneurship that is taken into consideration by this abstract plays a very important role because it highlights the story of many people who have managed to build such a close bond with the new territory of arrival that they can imagine and then realize the construction of their own personal business. The margin of contrast between the imagined city and the one that will be inhabited will be observed through the narratives of those who, through the realization of his business project has acted directly on the reality in which he landed. The margin of contrast that exists between the imagined city and the one actually inhabited, together with the implications that this may have on real life, has been observed and analyzed through a period of fieldwork, practicing ethnography, through the narratives of people who find themselves living in a new city as a result of a migration path, and has been contextualized with the support of semi-structured interviews and field notes. At the theoretical level, the research is inserted into a constructionist framework, particularly suited to detect and analyze processes of change, construction of the imaginary and its own modification, being able to capture the consequent repercussions of this process on the conceptual, emotional and practical level.

Keywords: entrepreneurship, imagination, migration, resistance

Procedia PDF Downloads 135

Authors: Noor Ul Huda, Mushtaq Ahmed, Nadia Mushtaq, Naila Sher, Rahmat Ali Khan

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Purpose: The green synthesis of AgNPs has been favored over chemical synthesis due to their distinctive properties such as high dispersion, surface-to-volume ratio, low toxicity, and easy preparation. In the present work, the biosynthesis of AgNPs (KE-AgNPs) was carried out in one step by using the traditionally used plant Kickxia elatine (KE) extract and then investigated its enzyme inhibiting activity against rat’s brain acetylcholinesterase (AChE) in vitro. Methods: KE-AgNPs were synthesized from 1mM AgNO₃ using KE extract and characterized by UV–spectroscopy, SEM, EDX, XRD, and FTIR analysis. Rat’s brain acetylcholinesterase (AChE) inhibition activity was evaluated by the standard protocol. Results: UV–spectrum at 416 nm confirmed the formation of KE-AgNPs. X-ray diffraction (XRD) pattern presented 2θ values corresponding to the crystalline nature of KE-AgNPs with an average size of 42.47nm. The scanning electron microscope (SEM) analysis confirmed the presence of spherical-shaped and huge density KE-AgNPs with a size of 50nm. Fourier transform infrared spectroscopy (FT-IR) suggested that the functional groups present in KE extract and on the surface of KE-AgNPs are responsible for the stability of biosynthesized NPs. Energy dispersive X-ray (EDX) displayed an intense sharp peak at 3.2 keV, presenting that Ag was the chief element with 61.67%. Both KE extract and KE-AgNPs showed good and potent anti-AChE activity, with higher inhibition potential at a concentration of 175 µg/ml. Statistical analysis showed that both KEE and AgNPs exhibited non-competitive type inhibition against AChE, i.e., Vmax decreased (34.17-68.64% and 22.29- 62.10%) in the concentration-dependent mode for KEE and KE-AgNPs respectively and while Km values remained constant. Conclusions: KEE and KE-AgNPs can be considered an inhibitor of rats’ brain AChE, and the synthesis of KE-AgNPs-based drugs can be used as a cheaper and alternative option against diseases such as Alzheimer’s disease.

Keywords: Kickxia elatine, AgNPs, brain homogenate, acetylcholinesterase, kinetics

Procedia PDF Downloads 103

Authors: Jae-Il Jeong, Hoon-Jae Park, Jung-Woo Cho, Yang-Gon Kim, Jin-Young Park, Joo-Young Oh, Si-Geun Choi, Seock-Sam Kim, Young Tae Cho, Chan Gyu Kim, Jong-Hyoung Kim

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Bearing component has strongly required to decrease vibration and wear to achieve high durability and life time. In the industry field, bearing durability is improved by surface treatment on the bearing surface by centrifugal casting or gravity casting production method. However, this manufacturing method has caused problems such as long processing time, defect rate, and health harmful effect. To solve this problem, there is a laser cladding deposition treatment, which provides fast processing and food adhesion. Therefore, optimum conditions of white metal laser deposition should be studied to minimize bearing contact axis wear using laser cladding techniques. In this study, we deposit a soft white metal layer on SCM440, which is mainly used for shaft and bolt. On laser deposition process, the laser power and powder feed rate and laser head speed factors are controlled to find out the optimal conditions. We also measure hardness using micro Vickers, analyze FE-SEM (Field Emission Scanning Electron Microscope) and EDS (Energy Dispersive Spectroscopy) to study the mechanical properties and surface characteristics with various parameters change. Furthermore, this paper suggests the optimum condition of laser cladding deposition to apply in industrial fields. This work was supported by the Industrial Innovation Project of the Korea Evaluation Institute of Industrial Technology (KEIT) granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (Research no. 10051653).

Keywords: laser deposition, bearing, white metal, mechanical properties

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Authors: Angelo Corallo, Maria Elena Latino, Marta Menegoli

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Agri-food value chain involves various stakeholders with different roles. All of them abide by national and international rules and leverage marketing strategies to advance their products. Food products and related processing phases carry with it a big mole of data that are often not used to inform final customer. Some data, if fittingly identified and used, can enhance the single company, and/or the all supply chain creates a math between marketing techniques and voluntary traceability strategies. Moreover, as of late, the world has seen buying-models’ modification: customer is careful on wellbeing and food quality. Food citizenship and food democracy was born, leveraging on transparency, sustainability and food information needs. Internet of Things (IoT) and Analytics, some of the innovative technologies of Industry 4.0, have a significant impact on market and will act as a main thrust towards a genuine ‘4.0 change’ for agriculture. But, realizing a traceability system is not simple because of the complexity of agri-food supply chain, a lot of actors involved, different business models, environmental variations impacting products and/or processes, and extraordinary climate changes. In order to give support to the company involved in a traceability path, starting from business model analysis and related business process a Framework to Manage Product Data in Agri-Food Supply Chain for Voluntary Traceability was conceived. Studying each process task and leveraging on modeling techniques lead to individuate information held by different actors during agri-food supply chain. IoT technologies for data collection and Analytics techniques for data processing supply information useful to increase the efficiency intra-company and competitiveness in the market. The whole information recovered can be shown through IT solutions and mobile application to made accessible to the company, the entire supply chain and the consumer with the view to guaranteeing transparency and quality.

Keywords: agriculture 4.0, agri-food suppy chain, industry 4.0, voluntary traceability

Procedia PDF Downloads 133

Authors: Cristian Moisa, Andreea Lupitu, Adriana Csakvari, Dana G. Radu, Leonard Marian Olariu, Georgeta Pop, Dorina Chambre, Lucian Copolovici, Dana Copolovici

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Green synthesis of nanoparticles (NPs) represents a promising, accessible, eco-friendly, and safe process with significant applications in biotechnology, pharmaceutical sciences, and farming. The aim of our study was to obtain silver nanoparticles, using plant wastes extracts resulted in the essential oils extraction process: Thymus vulgaris L., Origanum vulgare L., Lavandula angustifolia L., and in hemp processing for seed and fibre, Cannabis sativa. Firstly, we obtained aqueous extracts of thyme, oregano, lavender, and hemp (two monoicous and one dioicous varieties), all harvested in western part of Romania. Then, we determined the chemical composition of the extracts by liquid-chromatography coupled with diode array and mass spectrometer detectors. The compounds identified in the extracts were in agreement with earlier published data, and the determination of the antioxidant activity of the obtained extracts by DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) assays confirmed their antioxidant activity due to their total polyphenolic content evaluated by Folin-Ciocalteu assay. Then, the silver nanoparticles (AgNPs) were successfully biosynthesised, as was demonstrated by UV-VIS, FT-IR spectroscopies, and SEM, by reacting AgNO₃ solution and plant extracts. AgNPs were spherical in shape, with less than 30 nm in diameter, and had a good bactericidal activity against Gram-positive (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Pseudomonas fluorescens).

Keywords: plant wastes extracts, chemical composition, high performance liquid chromatography mass spectrometer, HPLC-MS, scanning electron microscopy, SEM, silver nanoparticles

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Authors: Patricia Portugal Marques de Carvalho Lourenco

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A three-phase methodological multi-lingual path was designed, constructed and carried out using the 2020 Chinese Internet Drama Series We Are All Alone as a case study. Phase one, the backbone of the research, comprised of secondary data analysis, providing the structure on which the next two phases would be built on. Phase one incorporated a Google Scholar and a Baidu Index analysis, Star Network Influence Index and Mydramalist.com top two drama reviews, along with an article written about the drama and scrutiny of Chinese related blogs and websites. Phase two was field research elaborated across Latin Europe, and phase three was social media focused, having into account that perceptions are going to be memory conditioned based on past ideas recall. Overall, research has shown the poor cultural expression of Chinese entertainment in Latin Europe and demonstrated the inexistence of Chinese content in French, Italian, Portuguese and Spanish Business to Consumer retailers; a reflection of their low significance in Latin European markets and the short-life cycle of entertainment products in general, bubble-gum, disposable goods without a mid to long-term effect in consumers lives. The process of conducting comprehensive international research was complex and time-consuming, with data not always available in Mandarin, the researcher’s linguistic deficiency, limited Chinese Cultural Knowledge and cultural equivalence. Despite steps being taken to minimize the international proposed research, theoretical limitations concurrent to Latin Europe and China still occurred. Data accuracy was disputable; sampling, data collection/analysis methods are heterogeneous; ascertaining data requirements and the method of analysis to achieve a construct equivalence was challenging and morose to operationalize. Secondary data was also not often readily available in Mandarin; yet, in spite of the array of limitations, research was done, and results were produced.

Keywords: research methodologies, international research, primary data, secondary data, research limitations, online dramas, china, latin europe

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Authors: Sahin Yakut, H. Kemal Ulutas, Deniz Deger

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Plasma Assisted Physical Vapor Deposition (PAPVD) method used to produce Poly(ethylene oxide) (pPEO) thin films. Depositions were progressed at various plasma discharge powers as 0, 2, 5 and 30 W for pPEO at 500nm film thicknesses. The capacitance and dielectric dissipation of the thin films were measured at 0,1-107 Hz frequency range and 173-353 K temperature range by an impedance analyzer. Then, alternative conductivity (σac) and activation energies were derived from capacitance and dielectric dissipation. σac of conventional PEO (PEO precursor) was measured to determine the effect of plasma discharge. Differences were observed between the alternative conductivity of PEO’s and pPEO’s depending on plasma discharge power. By this purpose, structural characterization techniques such as Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FT-IR) were applied on pPEO thin films. Structural analysis showed that density of crosslinking is plasma power dependent. The crosslinking density increases with increasing plasma discharge power and this increase is displayed as increasing dynamic glass transition temperatures at DSC results. Also, shifting of frequencies of some type of bond vibrations, belonging to bond vibrations produced after fragmentation because of plasma discharge, were observed at FTIR results. The dynamic glass transition temperatures obtained from alternative conductivity results for pPEO consistent with the results of DSC. Activation energies exhibit Arrhenius behavior. Activation energies decrease with increasing plasma discharge power. This behavior supports the suggestion expressing that long polymer chains and long oligomers are fragmented into smaller oligomers or radicals.

Keywords: activation energy, dielectric spectroscopy, organic thin films, plasma polymer

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Authors: Hasan Türe, Kader Terzioglu, Evren Tunca

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Contamination of aqueous environment by heavy metal ions is a serious and complex problem, owing to their hazards to human being and ecological systems. The treatment methods utilized for removing metal ions from aqueous solution include membrane separation, ion exchange and chemical precipitation. However, these methods are limited by high operational cost. Recently, biobased beads are considered as promising biosorbent to remove heavy metal ions from water. The aim of present study was to characterize the alginate/perlite composite beads and to investigate the adsorption performance of obtained beads for removing Pb (II) from aqueous solution. Alginate beads were synthesized by ionic gelation methods and different amount of perlite (aljinate:perlite=1, 2, 3, 4, 5 wt./wt.) was incorporated into alginate beads. Samples were characterized by means of X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM). The effects of perlite level, the initial concentration of Pb (II), initial pH value of Pb(II) solution and effect of contact time on the adsorption capacity of beads were investigated by using batch method. XRD analysis indicated that perlite includes silicon or silicon and aluminum bearing crystalline phase. The diffraction pattern of perlite containing beads is similar to that of that perlite powder with reduced intensity. SEM analysis revealed that perlite was embedded into alginate polymer and SEM-EDX (Energy-Dispersive X-ray) showed that composite beads (aljinate:perlite=1) composed of C (41.93 wt.%,), O (43.64 wt.%), Na (10.20 wt.%), Al (0.74 wt.%), Si (2.72 wt.%) ve K (0.77 wt.%). According to TGA analysis, incorporation of perlite into beads significantly improved the thermal stability of the samples. Batch experiment indicated that optimum pH value for Pb (II) adsorption was found at pH=7 with 1 hour contact time. It was also found that the adsorption capacity of beads decreased with increases in perlite concentration. The results implied that alginate/perlite composite beads could be used as promising adsorbents for the removal of Pb (II) from wastewater. Acknowledgement: This study was supported by TUBITAK (Project No: 214Z146).

Keywords: alginate, adsorption, beads, perlite

Procedia PDF Downloads 272

Authors: Muhammad Arif Rahman, Gamma Abdul Jabbar, Enggar Handra Pangestu, Alfi Syahrin Qadri, Iryan Anugrah Putra, Rizqi Ramadhandi.

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Indonesia lies above three major tectonic plates, Indo-Australia plate, Eurasia plate, and Pacific plate. Interactions between those plates resulted in high tectonic and volcanic activities that corelates into high risk of geological hazards in adjacent areas, one of the areas is in North of Sulawesi’s Islands. This case raises a problem in terms of infrastructure in order to mitigate existing infrastructure and various future infrastructures plan. One of the infrastructures that is essentials to enhance telecommunication aspect is submarine fiber optic cable, that has risk to geological hazard. This cable is essential that act as backbone in telecommunication. Damaged fiber optic cables can pose serious problem that make existing signal to be loss and have negative impact to people’s social and economic factor with also decreasing various governmental services performance. Submarine cables are facing challenges in terms of geological hazards, for instance are seamounts activity. Previous studies show that until 2023, five seamounts are identified in North of Sulawesi. Seamounts itself can damage and trigger many activities that can risks submarine cables, one of the examples is submarine landslide. Main focuses of this study are to identify new possible seamounts and submarine landslide path in area North of Sulawesi Islands to help minimize risks pose by those hazards, either to existing or future plan submarine cables. Using bathymetry data, this study conduct slope analysis and use distinctive morphological features to interpret possible seamounts. Then we mapped out valleys in between seamounts and determine where sediments might flow in case of landslide, and to finally, know how it affect submarine cables in the area.

Keywords: bathymetry, geological hazard, mitigation, seamount, submarine cable, submarine landslide, volcanic activity

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Authors: Ann Ying-An Chen, Yi-Lun Tsai, Hso-Chi Chaung

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An understanding of pathogens and the immune system has played an utmost important role in agricultural research for the development of vaccinations. The immunological synapse, cell to cell interaction play a crucial role in triggering the body's immune system, such as activation between antigen-presenting cells (APCs) and different subsets of T-cell. If these interactions are regulated appropriately, the host has the ability to defend itself against a wide spectrum of infectious pathogens. The aim of this study is to establish and to characterize a porcine immune synapse system by co-culturing T cell/APC. In this study, blood samples were collected from specific-pathogen-free piglets, and peripheral blood mononuclear cells (PBMC) were separated by using Ficoll-Pague. The PBMC were then stained with CD4 (FITC) and CD25 (PE) antibodies. Different subsets of T cells sorted by fluorescence-activated cell sorting flow cytometer were co-cultured for 24 hrs with alveolar macrophages, and the profiles of cytokine secretion and mRNA transcription levels of Toll-like receptors were examined after. Results showed that the three stages of immune synapse were clearly visible and identified under both transmission and scanning electron microscope (TEM and SEM). The significant interaction differences in toll-like receptor expressions within the co-cultured cell system were observed. The TLR7 mRNA expressions in CD4+CD25- cells were lower than those in CD4+CD25+ and CD4 -CD25+. Interestingly, the IL-10 production levels in CD4+CD25- cells (7.732 pg/mL) were significantly higher than those of CD4+CD25+ (2.636 pg/mL) and CD4 -CD25+ (2.48 pg/mL). These findings demonstrated that a clear understanding of the porcine immune synapse system can contribute greatly for further investigations on the mechanism of T-cell activation, which can benefit in the discovery of potential adjuvant candidate or effective antigen epitopes in the development of vaccinations with high efficacy.

Keywords: antigen-presenting cells, immune synapse, pig, T subsets, toll-like receptor

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Authors: Yehya Elsayed, Sarah Dalibalta, Fareedah Alqtaishat, Ioline Gomes, Nagelle Fernandes

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Bakhour or Arabian incense is traditionally used to perfume houses, shops and clothing as part of cultural or religious practices in several Middle Eastern countries. Conventionally, Bakhour consists of a mixture of natural ingredients such as chips of agarwood (oud), musk and sandalwoods that are soaked in scented oil. Bakhour is usually burned by charcoal or by using gas or electric burners to produce the scented smoke. It is necessary to evaluate the impact of such practice on human health and environment especially that the burning of Bakhour is usually done on a regular basis and in closed areas without proper ventilation. Although significant amount of research has been reported in scientific literature on the chemical analysis of various types of incense smoke, unfortunately only very few of them focused specifically on the health impacts of Bakhour. Raw Bakhour samples, their smoke emissions and the ash residue were analyzed to assess the existence of toxic ingredients and their possible influence on health and the environment. Three brands of Bakhour samples were analyzed for the presence of harmful heavy metals and organic compounds. Thermal Desorption Gas Chromatography-Mass Spectrometry (TD-GC-MS) was used to identify organic compounds while Inductively Coupled Plasma (ICP) and Scanning Electron Microscope-Energy Dispersive X-Ray Spectrometer (SEM-EDS) were used to analyze the presence of toxic and heavy metals. Organic compounds from the smoke were collected on specific tenax and activated carbon adsorption tubes. More than 850 chemical compounds were identified. The presence of 19 carcinogens, 23 toxins and 173 irritants were confirmed. Additionally, heavy metals were detected in amounts similar to those present in cigarettes. However, it was noticed that many of the detected compounds in the smoke lacked clinical studies on their health effects which shows the need for further clinical studies to be devoted to this area of study.

Keywords: Bakhour, incense smoke, pollution, indoor environment, health risk, chemical analysis

Procedia PDF Downloads 413

Authors: Yehya Elsayed, Sarah Dalibalta, Fareedah Alqtaishat, Ioline Gomes, Nagelle Fernandes

Abstract:

Bakhour, or Arabian incense, is traditionally used to perfume houses, shops and clothing as part of cultural or religious practices in several Middle Eastern countries. Conventionally, Bakhour consists of a mixture of natural ingredients such as chips of agarwood (oud), musk and sandalwoods that are soaked in scented oil. Bakhour is usually burned by charcoal or by using gas or electric burners to produce the scented smoke. It is necessary to evaluate the impact of such practice on human health and environment especially that the burning of Bakhour is usually done on a regular basis and in closed areas without proper ventilation. Although significant amount of research has been reported in scientific literature on the chemical analysis of various types of incense smoke, unfortunately, only very few of them focused specifically on the health impacts of Bakhour. Raw Bakhour samples, their smoke emissions and the ash residue were analyzed to assess the existence of toxic ingredients and their possible influence on health and the environment. Three brands of Bakhour samples were analyzed for the presence of harmful heavy metals and organic compounds. Thermal Desorption Gas Chromatography-Mass Spectrometry (TD-GC-MS) was used to identify organic compounds while Inductively Coupled Plasma (ICP) and Scanning Electron Microscope-Energy Dispersive X-Ray Spectrometer (SEM-EDS) were used to analyze the presence of toxic and heavy metals.. Organic compounds from the smoke were collected on specific tenax and activated carbon adsorption tubes. More than 850 chemical compounds were identified. The presence of 19 carcinogens, 23 toxins, and 173 irritants were confirmed. Additionally, heavy metals were detected in amounts similar to those present in cigarettes. However, it was noticed that many of the detected compounds in the smoke lacked clinical studies on their health effects which shows the need for further clinical studies to be devoted to this area of study.

Keywords: bakhour, incense smoke, pollution, indoor environment, health risk, chemical analysis

Procedia PDF Downloads 275

Authors: Krasimira Georgieva, Yordan Denev

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Many of thermosetting resins have application only in filled state, reinforced with different mineral fillers. The co-filling of polymers with mineral filler and gases creates a possibility for production of polymer composites materials with low density. This processing leads to forming of new materials – gas-filled plastics (polymer foams). The properties of these materials are determined mainly by the shape and size of internal structural elements (pores). The interactions on the phase boundaries have influence on the materials properties too. In the present work, the gas-filled urea-formaldehyde resins were reinforced by waste phosphogypsum. The waste phosphogypsum (CaSO₄.2H₂O) is a solid by-product in wet phosphoric acid production processes. The values of the interactions polymer-filler were increased by using two modifying agents: polyvinyl acetate for polymer matrix and sodium metasilicate for filler. Technological methods for gas-filling and recipes of urea-formaldehyde based materials with apparent density 20-120 kg/m³ were developed. The heat conductivity of the samples is between 0.024 and 0.029 W/m^oK. Tensile analyses were carried out at 10 and 50% deformation and show values 0.01-0.14 MPa and 0.01-0.09 MPa, respectively. The apparent density of obtained materials is between 20 and 92 kg/m³. The changes in the tensile properties and density of these materials according to sodium metasilicate content were studied too. The mechanism of phosphogypsum adsorption modification was studied using methods of FT-IR spectroscopy. The structure of the gas-filled urea-formaldehyde resins was described by results of electron scanning microscopy at three different magnification ratios – x50, x150 and x 500. The aim of present work is to study the possibility of the usage of phosphogypsum as mineral filler for urea-formaldehyde resins and development of a technology for the production of gas-filled reinforced polymer composite materials. The structure and the properties of obtained composite materials are suitable for thermal and sound insulation applications.

Keywords: urea formaldehyde resins, gas-filled thermostes, phosphogypsum, mechanical properties

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Authors: Mohamed Abd Elfattah Ibraheem Elghrbawy

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Biodeterioration of cultural heritage is a complex process which is caused by the interaction of many physical, chemical and biological agents; the growth of microorganisms can cause staining, cracking, powdering, disfigurement and displacement of monuments material, which leads to the permanent loss of monuments material. Organisms causing biodeterioration on monuments have usually been controlled by chemical products (biocides). In order to overcome the impact of biocides on the environment, human health and monument substrates, alternative tools such as antimicrobial agents from natural products can be used for monuments conservation and protection. The problem is how to formulate antibacterial agents with high efficiency and low toxicity. Various types of biodegradable metal nanoparticles (MNPs) have many applications in plant extract delivery. So, Nano-encapsulation of metal and natural antimicrobial agents using polymers such as chitosan increases their efficacy, specificity and targeting ability. Green synthesis and characterization of metal nanoparticles such as silver with natural products extracted from some plants having antimicrobial properties, using the ecofriendly method one pot synthesis. Encapsulation of the new synthesized mixture using some biopolymers such as chitosan nanoparticles. The dispersions and homogeneity of the antimicrobial heterogeneous metal nanoparticles encapsulated by biopolymers will be characterized and confirmed by Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM) and Zeta seizer. The effect of the antimicrobial biopolymer metal nano-formulations on normal human cell lines will be investigated to evaluate the environmental safety of these formulations. The antimicrobial toxic activity of the biopolymeric antimicrobial metal nanoparticles formulations will be will be investigated to evaluate their efficiency towards different pathogenic bacteria and fungi.

Keywords: antimicrobial, biodeterioration, chitosan, cultural heritage, silver

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Authors: Mark Andrew

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Geopolitical tensions are at a thirty-year high, and the pace of technological innovation is driving asymmetry in force capabilities between nation states and between non-state actors. Technology futures are a vital component of defence capability growth, and investments in technology futures need to be informed by accurate and reliable forecasts of the options for ‘systems of systems’ innovation, development, and deployment. This paper describes a method for forecasting technology futures developed through an analysis of four key systems’ development stages, namely: technology domain categorisation, scanning results examining novel systems’ signals and signs, potential system-of systems’ implications in warfare theatres, and political ramifications in terms of funding and development priorities. The method has been applied to several technology domains, including physical systems (e.g., nano weapons, loitering munitions, inflight charging, and hypersonic missiles), biological systems (e.g., molecular virus weaponry, genetic engineering, brain-computer interfaces, and trans-human augmentation), and information systems (e.g., sensor technologies supporting situation awareness, cyber-driven social attacks, and goal-specification challenges to proliferation and alliance testing). Although the current application of the method has been team-centred using paper-based rapid prototyping and iteration, the application of autonomous language models (such as GPT-3) is anticipated as a next-stage operating platform. The importance of forecasting accuracy and reliability is considered a vital element in guiding technology development to afford stronger contingencies as ideological changes are forecast to expand threats to ecology and earth systems, possibly eclipsing the traditional vulnerabilities of nation states. The early results from the method will be subjected to ground truthing using longitudinal investigation.

Keywords: forecasting, technology futures, uncertainty, complexity

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Authors: Ergin Kosa, Ali Göksenli

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Erosion and abrasion are wear mechanisms reducing the lifetime of machine elements like valves, pump and pipe systems. Both wear mechanisms are acting at the same time, causing a “Synergy” effect, which leads to a rapid damage of the surface. Different parameters are effective on erosive abrasive wear rate. In this study effect of particle impact angle on wear rate and wear mechanism of ductile and brittle materials was investigated. A new slurry pot was designed for experimental investigation. As abrasive particle, silica sand was used. Particle size was ranking between 200-500 µm. All tests were carried out in a sand-water mixture of 20% concentration for four hours. Impact velocities of the particles were 4,76 m/s. As ductile material steel St 37 with Brinell Hardness Number (BHN) of 245 and quenched St 37 with 510 BHN was used as brittle material. After wear tests, morphology of the eroded surfaces were investigated for better understanding of the wear mechanisms acting at different impact angles by using optical microscopy and Scanning Electron Microscope. The results indicated that wear rate of ductile material was higher than brittle material. Maximum wear was observed by ductile material at a particle impact angle of 300. On the contrary wear rate increased by brittle materials by an increase in impact angle and reached maximum value at 450. High amount of craters were detected after observation on ductile material surface Also plastic deformation zones were detected, which are typical failure modes for ductile materials. Craters formed by particles were deeper according to brittle material worn surface. Amount of craters decreased on brittle material surface. Microcracks around craters were detected which are typical failure modes of brittle materials. Deformation wear was the dominant wear mechanism on brittle material. At the end it is concluded that wear rate could not be directly related to impact angle of the hard particle due to the different responses of ductile and brittle materials.

Keywords: erosive wear, particle impact angle, silica sand, wear rate, ductile-brittle material

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Authors: Ourvashi Bissoon

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Sub-Saharan Africa in addition to being resource rich is increasingly being seen as having a huge growth potential and as a result, is increasingly attracting MNEs on its soil. To empirically assess the effectiveness of GDP in tracking sustainable resource use and the role played by MNEs in Sub-Saharan Africa, a panel data analysis has been undertaken for 32 countries over thirty-five years. The time horizon spans the period 1980-2014 to reflect the evolution from before the publication of the pioneering Brundtland report on sustainable development to date. Multinationals’ presence is proxied by the level of FDI stocks. The empirical investigation first focuses on the impact of trade openness and MNE presence on the traditional measure of economic growth namely the GDP growth rate, and then on the genuine savings (GS) rate, a measure of weak sustainability developed by the World Bank, which assumes the substitutability between different forms of capital and finally, the impact on the adjusted Net National Income (aNNI), a measure of green growth which caters for the depletion of natural resources is examined. For countries with significant exhaustible natural resources and important foreign investor presence, the adjusted net national income (aNNI) can be a better indicator of economic performance than GDP growth (World Bank, 2010). The issue of potential endogeneity and reverse causality is also addressed in addition to robustness tests. The findings indicate that FDI and openness contribute significantly and positively to the GDP growth of the countries in the sample; however there is a threshold level of institutional quality below which FDI has a negative impact on growth. When the GDP growth rate is substituted for the GS rate, a natural resource curse becomes evident. The rents being generated from the exploitation of natural resources are not being re-invested into other forms of capital namely human and physical capital. FDI and trade patterns may be setting the economies in the sample on a unsustainable path of resource depletion. The resource curse is confirmed when utilising the aNNI as well, thus implying that GDP growth measure may not be a reliable to capture sustainable development.

Keywords: FDI, sustainable development, genuine savings, sub-Saharan Africa

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Authors: Hamideh Hamedi, Nima Rezaei, Sohrab Zendehboudi

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Separating emulsified oil contaminations from waste- or produced water is of interest to various industries. Magnetic particles (MPs) application for separating dispersed and emulsified oil from wastewater is becoming more popular. Stabilization of MPs is required through developing a coating layer on their surfaces to prevent their agglomeration and enhance their dispersibility. In this research, we study the effects of coating material, size, and concentration of iron oxide MPs on oil separation efficiency, using oil adsorption capacity measurements. We functionalize both micro-and nanoparticles of Fe3O4 using sodium dodecyl sulfate (SDS) as an anionic surfactant, cetyltrimethylammonium bromide (CTAB) as a cationic surfactant, and stearic acid (SA). The chemical structures and morphologies of these particles are characterized using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Energy Dispersive X-ray (EDX). The oil-water separation results indicate that a low dosage of the coated magnetic nanoparticle with CTAB (0.5 g/L MNP-CTAB) results the highest oil adsorption capacity (nearly 100%) for 1000 ppm dodecane-in-water emulsion, containing ultra-small droplets (250–300 nm). While separation efficiency of the same dosage of bare MNPs is around 57.5%. Demulsification results of magnetic microparticles (MMPs) also reveal that the functionalizing particles with CTAB increase oil removal efficiency from 86.3% for bare MMP to 92% for MMP-CTAB. Comparing the results of different coating materials implies that the major interaction reaction is an electrostatic attraction between negatively charged oil droplets and positively charged MNP-CTAB and MMP-CTAB. Furthermore, the synthesized nanoparticles could be recycled and reused; after ten cycles the oil adsorption capacity slightly decreases to near 95%. In conclusion, functionalized magnetic particles with high oil separation efficiency could be used effectively in treatment of oily wastewater. Finally, optimization of the adsorption process is required by considering the effective system variables, and fluid properties.

Keywords: oily wastewater treatment, emulsions, oil-water separation, adsorption, magnetic nanoparticles

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Authors: Gülcan Taşkıran, Ayla Bayık Temel

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Background: Florence Nightingale, the modern founder of the nursing, is most famous for her role as a nurse. But not so much known about her contributions as a mathematician and statistician. Aim: In this conceptual article it is aimed to examine Florence Nightingale's statistics education, how she used her passion for statistics and applied statistical data in nursing care and her scientific contributions to statistical science. Design: Literature review method was used in the study. The databases of Istanbul University Library Search Engine, Turkish Medical Directory, Thesis Scanning Center of Higher Education Council, PubMed, Google Scholar, EBSCO Host, Web of Science were scanned to reach the studies. The keywords 'statistics' and 'Florence Nightingale' have been used in Turkish and English while being screened. As a result of the screening, totally 41 studies were examined from the national and international literature. Results: Florence Nightingale has interested in mathematics and statistics at her early ages and has received various training in these subjects. Lessons learned by Nightingale in a cultured family environment, her talent in mathematics and numbers, and her religious beliefs played a crucial role in the direction of the statistics. She was influenced by Quetelet's ideas in the formation of the statistical philosophy and received support from William Farr in her statistical studies. During the Crimean War, she applied statistical knowledge to nursing care, developed many statistical methods and graphics, so that she made revolutionary reforms in the health field. Conclusions: Nightingale's interest in statistics, her broad vision, the statistical ideas fused with religious beliefs, the innovative graphics she has developed and the extraordinary statistical projects that she carried out has been influential on the basis of her professional achievements. Florence Nightingale has also become a model for women in statistics. Today, using and teaching of statistics and research in nursing care practices and education programs continues with the light she gave.

Keywords: Crimean war, Florence Nightingale, nursing, statistics

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Authors: E. M. Rifqi Wilda Pradana, Bagus Bayu Prabowo, Meida Riski Pujiyati, Efraim Maykhel Hagana Ginting, Virgiawan Arya Hangga Reksa

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The VLF (Very Low Frequency) method is an electromagnetic method that uses low frequencies between 10-30 KHz which results in a fairly deep penetration. In this study, the VLF method was used for zonation of disaster-prone areas by identifying geological structures in the form of faults. Data acquisition was carried out in Trimulyo Region, Jetis District, Bantul Regency, Special Region of Yogyakarta, Indonesia with 8 measurement paths. This study uses wave transmitters from Japan and Australia to obtain Tilt and Elipt values that can be used to create RAE (Rapat Arus Ekuivalen or Current Density) sections that can be used to identify areas that are easily crossed by electric current. This section will indicate the existence of a geological structure in the form of faults in the study area which is characterized by a high RAE value. In data processing of VLF method, it is obtained Tilt vs Elliptical graph and Moving Average (MA) Tilt vs Moving Average (MA) Elipt graph of each path that shows a fluctuating pattern and does not show any intersection at all. Data processing uses Matlab software and obtained areas with low RAE values that are 0%-6% which shows medium with low conductivity and high resistivity and can be interpreted as sandstone, claystone, and tuff lithology which is part of the Semilir Formation. Whereas a high RAE value of 10% -16% which shows a medium with high conductivity and low resistivity can be interpreted as a fault zone filled with fluid. The existence of the fault zone is strengthened by the discovery of a normal fault on the surface with strike N550W and dip 630E at coordinates X= 433256 and Y= 9127722 so that the activities of residents in the zone such as housing, mining activities and other activities can be avoided to reduce the risk of natural disasters.

Keywords: current density, faults, very low frequency, zonation

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Authors: Musa Akdere, Gunnar Seide, Thomas Gries

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Carbon fibres are fibrous materials with a carbon atom amount of more than 90%. They combine excellent mechanicals properties with a very low density. Thus carbon fibre reinforced plastics (CFRP) are very often used in lightweight design and construction. The precursor material is usually polyacrylonitrile (PAN) based and wet-spun. During the production of carbon fibre, the precursor has to be stabilized thermally to withstand the high temperatures of up to 1500 °C which occur during carbonization. Even though carbon fibre has been used since the late 1970s in aerospace application, there is still no general method available to find the optimal production parameters and the trial-and-error approach is most often the only resolution. To have a much better insight into the process the chemical reactions during stabilization have to be analyzed particularly. Therefore, a model of the chemical reactions (cyclization, dehydration, and oxidation) based on the research of Dunham and Edie has been developed. With the presented model, it is possible to perform a complete simulation of the fibre undergoing all zones of stabilization. The fiber bundle is modeled as several circular fibers with a layer of air in-between. Two thermal mechanisms are considered to be the most important: the exothermic reactions inside the fiber and the convective heat transfer between the fiber and the air. The exothermic reactions inside the fibers are modeled as a heat source. Differential scanning calorimetry measurements have been performed to estimate the amount of heat of the reactions. To shorten the required time of a simulation, the number of fibers is decreased by similitude theory. Experiments were conducted to validate the simulation results of the fibre temperature during stabilization. The experiments for the validation were conducted on a pilot scale stabilization oven. To measure the fibre bundle temperature, a new measuring method is developed. The comparison of the results shows that the developed simulation model gives good approximations for the temperature profile of the fibre bundle during the stabilization process.

Keywords: carbon fibre, coupled simulation, exothermic reactions, fibre-air-interface

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Authors: Moses C. Siame, Kazutoshi Haga, Atsushi Shibayama

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This study investigates the removal of silica, alumina and phosphorus as impurities from Sanje iron ore using wet high-intensity magnetic separation (WHIMS). Sanje iron ore contains low-grade hematite ore found in Nampundwe area of Zambia from which iron is to be used as the feed in the steelmaking process. The chemical composition analysis using X-ray Florence spectrometer showed that Sanje low-grade ore contains 48.90 mass% of hematite (Fe₂O₃) with 34.18 mass% as an iron grade. The ore also contains silica (SiO₂) and alumina (Al₂O₃) of 31.10 mass% and 7.65 mass% respectively. The mineralogical analysis using X-ray diffraction spectrometer showed hematite and silica as the major mineral components of the ore while magnetite and alumina exist as minor mineral components. Mineral particle distribution analysis was done using scanning electron microscope with an X-ray energy dispersion spectrometry (SEM-EDS) and images showed that the average mineral size distribution of alumina-silicate gangue particles is in order of 100 μm and exists as iron-bearing interlocked particles. Magnetic separation was done using series L model 4 Magnetic Separator. The effect of various magnetic separation parameters such as magnetic flux density, particle size, and pulp density of the feed was studied during magnetic separation experiments. The ore with average particle size of 25 µm and pulp density of 2.5% was concentrated using pulp flow of 7 L/min. The results showed that 10 T was optimal magnetic flux density which enhanced the recovery of 93.08% of iron with 53.22 mass% grade. The gangue mineral particles containing 12 mass% silica and 3.94 mass% alumna remained in the concentrate, therefore the concentrate was further treated in the second stage WHIMS using the same parameters from the first stage. The second stage process recovered 83.41% of iron with 67.07 mass% grade. Silica was reduced to 2.14 mass% and alumina to 1.30 mass%. Accordingly, phosphorus was also reduced to 0.02 mass%. Therefore, the two stage magnetic separation process was established using these results.

Keywords: Sanje iron ore, magnetic separation, silica, alumina, recovery

Procedia PDF Downloads 240

Authors: Paula C. Ferreira, Ana Margarida Veiga Simão, Nádia Pereira, Aristides Ferreira, Alexandra Marques Pinto, Alexandra Barros, Vitor Martinho

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Cyberbullying is a phenomenon of worldwide concern regarding children and adolescents’ mental health and risk behavior. Bystanders of this phenomenon can help diminish the incidence of this phenomenon if they engage in pro-social behavior. However, different social-cognitive and affective bystander reactions may surface because of the lack of contextual information and emotional cues in cyberbullying situations. Hence, this study investigated how cyberbullying bystanders’ unpleasant emotions could be related to their personal moral beliefs and their behavioral intentions to cyberbully or defend the victim. It also proposed to investigate how their normative beliefs of perceived severity about cyberbullying behavior could be related to their personal moral beliefs and their behavioral intentions. Three groups of adolescents participated in this study, namely a first of group 402 students (5th – 12th graders; Mage = 13.12; SD = 2.19; 55.7% girls) to compute explorative factorial analyses of the instruments used; a second group of 676 students (5th – 12th graders; Mage = 14.10; SD = 2.74; 55.5% were boys) to run confirmatory factor analyses; and a third group (N = 397; 5th – 12th graders; Mage = 13.88 years; SD = 1.45; 55.5% girls) to perform the main analyses to test the research hypotheses. Self-report measures were used, such as the Personal moral beliefs about cyberbullying behavior questionnaire, the Normative beliefs of perceived severity about cyberbullying behavior questionnaire, the Unpleasant emotions about cyberbullying incidents questionnaires, and the Bystanders’ behavioral intentions in cyberbullying situations questionnaires. Path analysis results revealed that unpleasant emotions were mediators of the relationship between adolescent cyberbullying bystanders’ personal moral beliefs and their intentions to help the victims in cyberbullying situations. Moreover, adolescent cyberbullying bystanders’ normative beliefs of gravity were mediators of the relationship between their personal moral beliefs and their intentions to cyberbully others. These findings provide insights for the development of prevention and intervention programs that promote social and emotional learning strategies as a means to prevent and intervene in cyberbullying.

Keywords: cyberbullying, normative beliefs of perceived severity, personal moral beliefs, unpleasant emotions

Procedia PDF Downloads 194

Authors: Angelis P. Barlampas

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Purpose or Learning Objective It is well known that previous examinations play a major role in futural diagnosis, thus avoiding unnecessary new exams that cost in time and money both for the patient and the health system. A case is presented in which past patient’s results, in combination with the least needed new tests, give an easy final diagnosis. Methods or Background A middle aged man visited the emergency department complaining of hard controlled, persisting fever for the last few days. Laboratory tests showed an elevated number of white blood cells with neutrophil shift and abnormal CRP. The patient was admitted to hospital a month ago for continuing lungs symptomatology after a recent covid-19 infection. Results or Findings Computed tomography scanning showed a solid mass with spiculating margins in right lower lobe. After intravenous iodine contrast administration, there was mildly peripheral enhancement and eccentric non enhancing area. A pneumonic cancer was suspected. Comparison with the patient’s latest computed tomography revealed no mass in the area of interest but only signs of recent post covid-19 lung parenchyma abnormalities. Any new mass that appears in a month’s time span can not be a cancer but a benign lesion. It was obvious that an abscess was the most suitable explanation. The patient was admitted to hospital, and antibiotic therapy was given, with very good results. After a few days, the patient was afebrile and in good condition. Conclusion In this case , a PET scan or a biopsy was avoided, thanks to the patient’s medical history and the availability of previous examinations. It is worthy encouraging the patients to keep their medical records and organizing more efficiently the health system with the current technology of archiving the medical examinations, too.

Keywords: covid-19, chest ct, cancer, abscess, fever

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Authors: Hend Albassam, Nouf Alrumaih

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Nowadays we are in the age of technologies and communication and there is no doubt that technologies such as the Internet can offer many advantages for many business fields, and the health field is no execution. In fact, using the Internet provide us with a new path to improve the quality of health care throughout the world. The e-healthcare offers many advantages such as: efficiency by reducing the cost and avoiding duplicate diagnostics, empowerment of patients by enabling them to access their medical records, enhancing the quality of healthcare and enabling information exchange and communication between healthcare organizations. There are many problems that result from using papers as a way of communication, for example, paper-based prescriptions. Usually, the doctor writes a prescription and gives it to the patient who in turn carries it to the pharmacy. After that, the pharmacist takes the prescription to fill it and give it to the patient. Sometimes the pharmacist might find difficulty in reading the doctor’s handwriting; the patient could change and counterfeit the prescription. These existing problems and many others heighten the need to improve the quality of the healthcare. This project is set out to develop a distributed e-healthcare system that offers some features of e-health and addresses some of the above-mentioned problems. The developed system provides an electronic health record (EHR) and enables communication between separate health care organizations such as the clinic, pharmacy and laboratory. To develop this system, the Service Oriented Architecture (SOA) is adopted as a design approach, which helps to design several independent modules that communicate by using web services. The layering design pattern is used in designing each module as it provides reusability that allows the business logic layer to be reused by different higher layers such as the web service or the website in our system. The experimental analysis has shown that the project has successfully achieved its aims toward solving the problems related to the paper-based healthcare systems and it enables different health organization to communicate effectively. It implements four independent modules including healthcare provider, pharmacy, laboratory and medication information provider. Each module provides different functionalities and is used by a different type of user. These modules interoperate with each other using a set of web services.

Keywords: e-health, services oriented architecture (SOA), web services, interoperability

Procedia PDF Downloads 292

Authors: Meghdad Payan, Kostas Senetakis, Arman Khoshghalb, Nasser Khalili

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Dynamic properties of soils, especially at the range of very small strains, are of particular interest in geotechnical engineering practice for characterization of the behavior of geo-structures subjected to a variety of stress states. This study reports on the small-strain dynamic properties of sand-silt mixtures with particular emphasis on the effect of non-plastic fines content on the small strain shear modulus (Gmax), Young’s Modulus (Emax), material damping (Ds,min) and Poisson’s Ratio (v). Several clean sands with a wide range of grain size characteristics and particle shape are mixed with variable percentages of a silica non-plastic silt as fines content. Prepared specimens of sand-silt mixtures at different initial void ratios are subjected to sequential torsional and flexural resonant column tests with elastic dynamic properties measured along an isotropic stress path up to 800 kPa. It is shown that while at low percentages of fines content, there is a significant difference between the dynamic properties of the various samples due to the different characteristics of the sand portion of the mixtures, this variance diminishes as the fines content increases and the soil behavior becomes mainly silt-dominant, rendering no significant influence of sand properties on the elastic dynamic parameters. Indeed, beyond a specific portion of fines content, around 20% to 30% typically denoted as threshold fines content, silt is controlling the behavior of the mixture. Using the experimental results, new expressions for the prediction of small-strain dynamic properties of sand-silt mixtures are developed accounting for the percentage of silt and the characteristics of the sand portion. These expressions are general in nature and are capable of evaluating the elastic dynamic properties of sand-silt mixtures with any types of parent sand in the whole range of silt percentage. The inefficiency of skeleton void ratio concept in the estimation of small-strain stiffness of sand-silt mixtures is also illustrated.

Keywords: damping ratio, Poisson’s ratio, resonant column, sand-silt mixture, shear modulus, Young’s modulus

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Authors: Gary Pattemore, Michael Edgar, Andrew Job, Marina Auad, Kathryn Job

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As critical commodities become more scarce, significant time and resources have been used to better understand complicated ore bodies and extract their full potential. These challenging ore bodies provide several pain points for geologists and engineers to overcome, poor handling of these issues flows downs stream to the processing plant affecting throughput rates and recovery. Many open cut mines utilise blast hole drilling to extract additional information to feed back into the modelling process. This method requires samples to be collected during or after blast hole drilling. Samples are then sent for assay with turnaround times varying from 1 to 12 days. This method is time consuming, costly, requires human exposure on the bench and collects elemental data only. To address this challenge, research has been undertaken to utilise hyperspectral imaging across a broad spectrum to scan samples, collars or take down hole measurements for minerals and moisture content and grade abundances. Automation of this process using unmanned vehicles and on-board processing reduces human in pit exposure to ensure ongoing safety. On-board processing allows data to be integrated into modelling workflows with immediacy. The preliminary results demonstrate numerous direct and indirect benefits from this new technology, including rapid and accurate grade estimates, moisture content and mineralogy. These benefits allow for faster geo modelling updates, better informed mine scheduling and improved downstream blending and processing practices. The paper presents recommendations for implementation of the technology in open cut mining environments.

Keywords: grade control, hyperspectral scanning, artificial intelligence, autonomous mining, machine learning

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Authors: Roopchand Tandon, Zaheer Khan Yusufzai, R. Manna, R. K. Mandal

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Present work describes microstructures, mechanical properties, and texture characteristics of the friction stir processed AA7075T7352 aluminum alloy. Phases were analyzed with the help of x-ray diffractometre (XRD), transmission electron microscope (TEM) along with the differential scanning calorimeter (DSC). Depth-wise microstructures and dislocation characteristics from the nugget-zone of the friction stir processed specimens were studied using the bright field (BF) and weak beam dark-field (WBDF) TEM micrographs, and variation in the microstructures as well as dislocation characteristics were the noteworthy features found. XRD analysis display changes in the chemistry as well as size of the phases in the nugget and heat affected zones (Nugget and HAZ). Whereas the base metal (BM) microstructures remain un-affected. High density dislocations were noticed in the nugget regions of the processed specimen, along with the formation of dislocation contours and tangles. .The ɳ’ and ɳ phases, along with the GP-Zones were completely dissolved and trapped by the dislocations. Such an observations got corroborated to the improved mechanical as well as stress corrosion cracking (SCC) performances. Bulk texture and residual stress measurements were done by the Panalytical Empyrean MRD system with Co- kα radiation. Nugget zone (NZ) display compressive residual stress as compared to thermo-mechanically(TM) and heat affected zones (HAZ). Typical f.c.c. deformation texture components (e.g. Copper, Brass, and Goss) were seen. Such a phenomenon is attributed to the enhanced hardening as well as other mechanical performance of the alloy. Mechanical characterizations were done using the tensile test and Anton Paar Instrumented Micro Hardness tester. Enhancement in the yield strength value is reported from the 89MPa to the 170MPa; on the other hand, highest hardness value was reported in the nugget-zone of the processed specimens.

Keywords: aluminum alloy, mechanical characterization, texture characterstics, friction stir processing

Procedia PDF Downloads 80