Search results for: solar radiation pressure

Authors: Joanna Szymanska, Paulina Wawulska-Marek, Jaroslaw Mizera

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Nowadays, the rapid growth of global energy consumption and uncontrolled depletion of natural resources become a serious problem. Shale rocks are the largest and potential global basins containing hydrocarbons, trapped in closed pores of the shale matrix. Regardless of the shales origin, mining conditions are extremely unfavourable due to high reservoir pressure, great depths, increased clay minerals content and limited permeability (nanoDarcy) of the rocks. Taking into consideration such geomechanical barriers, effective extraction of natural gas from shales with plastic zones demands effective operations. Actually, hydraulic fracturing is the most developed technique based on the injection of pressurized fluid into a wellbore, to initiate fractures propagation. However, a rapid drop of pressure after fluid suction to the ground induces a fracture closure and conductivity reduction. In order to minimize this risk, proppants should be applied. They are solid granules transported with hydraulic fluids to locate inside the rock. Proppants act as a prop for the closing fracture, thus gas migration to a borehole is effective. Quartz sands are commonly applied proppants only at shallow deposits (USA). Whereas, ceramic proppants are designed to meet rigorous downhole conditions to intensify output. Ceramic granules predominate with higher mechanical strength, stability in strong acidic environment, spherical shape and homogeneity as well. Quality of ceramic proppants is conditioned by raw materials selection. Aim of this study was to obtain the proppants from aluminosilicates (the kaolinite subgroup) and mix of minerals with a high alumina content. These loamy minerals contain a tubular and platy morphology that improves mechanical properties and reduces their specific weight. Moreover, they are distinguished by well-developed surface area, high porosity, fine particle size, superb dispersion and nontoxic properties - very crucial for particles consolidation into spherical and crush-resistant granules in mechanical granulation process. The aluminosilicates were mixed with water and natural organic binder to improve liquid-bridges and pores formation between particles. Afterward, the green proppants were subjected to sintering at high temperatures. Evaluation of the minerals utility was based on their particle size distribution (laser diffraction study) and thermal stability (thermogravimetry). Scanning Electron Microscopy was useful for morphology and shape identification combined with specific surface area measurement (BET). Chemical composition was verified by Energy Dispersive Spectroscopy and X-ray Fluorescence. Moreover, bulk density and specific weight were measured. Such comprehensive characterization of loamy materials confirmed their favourable impact on the proppants granulation. The sintered granules were analyzed by SEM to verify the surface topography and phase transitions after sintering. Pores distribution was identified by X-Ray Tomography. This method enabled also the simulation of proppants settlement in a fracture, while measurement of bulk density was essential to predict their amount to fill a well. Roundness coefficient was also evaluated, whereas impact on mining environment was identified by turbidity and solubility in acid - to indicate risk of the material decay in a well. The obtained outcomes confirmed a positive influence of the loamy minerals on ceramic proppants properties with respect to the strict norms. This research is perspective for higher quality proppants production with costs reduction.

Keywords: aluminosilicates, ceramic proppants, mechanical granulation, shale gas

Procedia PDF Downloads 163

Authors: Debananda Mohapatra, Subramanya Badrayyana, Smrutiranjan Parida

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Carbon nano-onions (CNOs) are the spherical graphitic nanostructures composed of concentric shells of graphitic carbon can be hypothesized as the intermediate state between fullerenes and graphite. These are very important members in fullerene family also known as the multi-shelled fullerenes can be envisioned as promising supercapacitor electrode with high energy & power density as they provide easy access to ions at electrode-electrolyte interface due to their curvature. There is still very sparse report concerning on CNOs as electrode despite having an excellent electrodechemical performance record due to their unavailability and lack of convenient methods for their high yield preparation and purification. Keeping all these current pressing issues in mind, we present a facile scalable and straightforward flame synthesis method of pure and highly dispersible CNOs without contaminated by any other forms of carbon; hence, a post processing purification procedure is not necessary. To the best of our knowledge, this is the very first time; we developed an extremely simple, light weight, novel inexpensive, flexible free standing pristine CNOs electrode without using any binder element. Locally available daily used cotton wipe has been used for fabrication of such an ideal electrode by ‘dipping and drying’ process providing outstanding stretchability and mechanical flexibility with strong adhesion between CNOs and porous wipe. The specific capacitance 102 F/g, energy density 3.5 Wh/kg and power density 1224 W/kg at 20 mV/s scan rate are the highest values that ever recorded and reported so far in symmetrical two electrode cell configuration with 1M Na2SO4 electrolyte; indicating a very good synthesis conditions employed with optimum pore size in agreement with electrolyte ion size. This free standing CNOs electrode also showed an excellent cyclic performance and stability retaining 95% original capacity after 5000 charge –discharge cycles. Furthermore, this unique method not only affords binder free - freestanding electrode but also provide a general way of fabricating such multifunctional promising CNOs based nanocomposites for their potential device applications in flexible solar cells and lithium-ion batteries.

Keywords: binder-free, flame synthesis, flexible, carbon nano onion

Procedia PDF Downloads 204

Authors: Wei Wang, Yuan Hu

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Epoxy resins (EP), one of the most important thermosetting polymers, is widely applied in various fields due to its desirable properties, such as excellent electrical insulation, low shrinkage, outstanding mechanical stiffness, satisfactory adhesion and solvent resistance. However, like most of the polymeric materials, EP has the fatal drawbacks including inherent flammability and high yield of toxic smoke, which restricts its application in the fields requiring fire safety. So, it is still a challenge and an interesting subject to develop new flame retardants which can not only remarkably improve the flame retardancy, but also render modified resins low toxic gases generation. In recent work, polymer nanocomposites based on nanohybrids that contain two or more kinds of nanofillers have drawn intensive interest, which can realize performance enhancements. The realization of previous hybrids of carbon nanotubes (CNTs) and molybdenum disulfide provides us a novel route to decorate layered double hydroxide (LDH) nanosheets on the surface of β-FeOOH nanorods; the deposited LDH nanosheets can fill the network and promote the work efficiency of β-FeOOH nanorods. Moreover, the synergistic effects between LDH and β-FeOOH can be anticipated to have potential applications in reducing fire hazards of EP composites for the combination of condense-phase and gas-phase mechanism. As reported, β-FeOOH nanorods can act as a core to prepare hybrid nanostructures combining with other nanoparticles through electrostatic attraction through layer-by-layer assembly technique. In this work, LDH nanosheets wrapped β-FeOOH nanorods (LDH-β-FeOOH) hybrids was synthesized by a facile method, with the purpose of combining the characteristics of one dimension (1D) and two dimension (2D), to improve the fire resistance of epoxy resin. The hybrids showed a well dispersion in EP matrix and had no obvious aggregation. Thermogravimetric analysis and cone calorimeter tests confirmed that LDH-β-FeOOH hybrids into EP matrix with a loading of 3% could obviously improve the fire safety of EP composites. The plausible flame retardancy mechanism was explored by thermogravimetric infrared (TG-IR) and X-ray photoelectron spectroscopy. The reasons were concluded: condense-phase and gas-phase. Nanofillers were transferred to the surface of matrix during combustion, which could not only shield EP matrix from external radiation and heat feedback from the fire zone, but also efficiently retard transport of oxygen and flammable pyrolysis.

Keywords: fire hazards, toxic gases, self-assembly, epoxy

Procedia PDF Downloads 174

Authors: L. F. Tamele Jr., G. Buonocore, H. F. Muiambo

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Asphalt binders play an essential role in the performance and properties of asphalt mixtures. The increase in heavy loads, greater traffic volume, and high tire pressure, combined with a substantial variation in daily and seasonal pavement temperatures, are the main responsible for the failure of asphalt pavements. To avoid or mitigate these failures, the present research proposes the use of thermoplastic polymers, HDPE and LLDPE, and nanoclay Dellite 43B for modification of asphalt in order to improve its thermomechanical and rheological properties. The nanocomposites were prepared by the solution intercalation method in a high shear mixer for a mixing time of 2 h, at 180℃ and 5000 rpm. The addition of Dellite 43B improved the physical, rheological, and thermal properties of asphalt, either separated or in the form of polymer/bitumen blends. The results of the physical characterization showed a decrease in penetration and an increase in softening point, thermal susceptibility, viscosity, and stiffness. On the other hand, thermal characterization showed that the nanocomposites have greater stability at higher temperatures by exhibiting greater amounts of residues and improved initial and final decomposition temperatures. Thus, the modification of asphalt by polymers and nanoclays seems to be a suitable solution for road pavement in countries which experiment with high temperatures combined with long heavy rain seasons.

Keywords: asphalt, nanoclay dellite 43B, polymer modified asphalt, thermal and rheological properties

Procedia PDF Downloads 147

Authors: T. Salami, O. S. Idowu, N. J. Bello

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Climatic variability is an essential issue when dealing with the issue of climate change. Variability of some climate parameter helps to determine how variable the climatic condition of a region will behave. The most important of these climatic variables which help to determine the climatic condition in an area are both the Temperature and Precipitation. This research deals with Longterm climatic variability in Nigeria. Variables examined in this analysis include near-surface temperature, near surface minimum temperature, maximum temperature, relative humidity, vapour pressure, precipitation, wet-day frequency and cloud cover using data ranging between 1901-2010. Analyses were carried out and the following methods were used: - Regression and EOF analysis. Results show that the annual average, minimum and maximum near-surface temperature all gradually increases from 1901 to 2010. And they are in the same case in a wet season and dry season. Minimum near-surface temperature, with its linear trends are significant for annual, wet season and dry season means. However, the diurnal temperature range decreases in the recent 100 years imply that the minimum near-surface temperature has increased more than the maximum. Both precipitation and wet day frequency decline from the analysis, demonstrating that Nigeria has become dryer than before by the way of rainfall. Temperature and precipitation variability has become very high during these periods especially in the Northern areas. Areas which had excessive rainfall were confronted with flooding and other related issues while area that had less precipitation were all confronted with drought. More practical issues will be presented.

Keywords: climate, variability, flooding, excessive rainfall

Procedia PDF Downloads 384

Authors: Ts. Lazarova, V. Tumbalev, S. Atanacova-Vladimirova, G. Ivanov, A. Naydenov, D. Kovacheva

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Methane is a major Greenhouse Gas (GHG) that accounts for 14% of the world’s total amount of GHG emissions, originating mainly from agriculture, Coal mines, land fields, wastewater and oil and gas facilities. Nowadays the problem caused by the methane emissions has been a subject of an increased concern. One of the methods for neutralization of the methane emissions is it's complete catalytic oxidation. The efforts of the researchers are focused on the development of new types of catalysts and optimizing the existing catalytic systems in order to prevent the sintering of the palladium, providing at the same time a sufficient activity at temperatures below 500oC. The aim of the present work is to prepare mixed Cu-Ag-Pd oxide catalysts supported on alumina and to test them for methane complete catalytic oxidation. Cu-Ag-Pd/Al2O3 were prepared on a γ-Al2O3 (BET surface area = 220 m2/g) by the incipient wetness method using the corresponding metal nitrates (Cu:Ag = 90:10, Cu:Pd =97:3, Cu:Ag:Pd= 87:10:3) as precursors. A second set of samples were prepared with addition of urea to the metal nitrate solutions with the above mentioned ratios assuming increased dispersivity of the catalysts. The catalyst samples were dried at 100°C for 3 hours and calcined at 550°C for 30 minutes. Catalysts samples were characterized using X-ray diffraction (XRD), low temperature adsorption of nitrogen (BET) and scanning electron microscopy (SEM). The catalytic activity tests were carried out in a continuous flow type of reactor at atmospheric pressure. The effect of catalyst aging at 500 oC for 120 h on the methane combustion activity was also investigated. The results clearly indicate the synergetic effect of Ag and Pd on the catalytic activity.

Keywords: catalysts, XRD, BET, SEM, catalytic oxidation

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Authors: Jocelyn Lachance, Francis Jauréguiberry

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In a few years, the exceptionality of the situation of an individual who could be reached at any time and at any time was replaced by the normality of instantly hearing the voice or immediately seeing the face of the person. This participates in the transformation of our representations of time and space, which gives rise to new expectations. Expectations that parents formulate more or less clearly to their children. The obligation to remain reachable seems to be asserting itself as a general norm which, having imposed itself on adults, now extends to the youngest. In the case of parents and their children, the rationale for this ongoing connection is not always based on actual and imminent dangers. It is the potential for dangerous events that underpins the indisputable argument for the importance of remaining reachable. It is the contingent nature of the risks that imposes itself on these young people as an argument of authority. By entering this connected world, the younger generations also end up adhering in many cases to this reassuring standard of connection. Many teenagers in ours researches nonetheless firmly believe that their freedom of movement is subject to the obligation to carry their smartphone with them. In this way, a connection "pact" is generally established, concluded under pressure, which implies first and foremost that contact be possible at any time, hence the importance of keeping it within reach, and often of '' be attentive to calls and texts sent by parents, at the risk of losing a recently acquired freedom. In this context, if adolescents are growing up in a connected world today, it is also because of the connection the parents are expecting from them. In our conference, by evoking situations reported by teenagers and parents of teenagers during our surveys, we propose to think about the role of the parents in making their child connected and about the desire of the disconnection of the teens.

Keywords: connection, disconnection, smartphone, parents, ritual

Procedia PDF Downloads 194

Authors: Karim Kheloufi, El Hachemi Amara

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In the present study, a three-dimensional transient numerical model was developed to study the temperature field and cutting kerf shape during laser fusion cutting. The finite volume model has been constructed, based on the Navier–Stokes equations and energy conservation equation for the description of momentum and heat transport phenomena, and the Volume of Fluid (VOF) method for free surface tracking. The Fresnel absorption model is used to handle the absorption of the incident wave by the surface of the liquid metal and the enthalpy-porosity technique is employed to account for the latent heat during melting and solidification of the material. To model the physical phenomena occurring at the liquid film/gas interface, including momentum/heat transfer, a new approach is proposed which consists of treating friction force, pressure force applied by the gas jet and the heat absorbed by the cutting front surface as source terms incorporated into the governing equations. All these physics are coupled and solved simultaneously in Fluent CFD®. The main objective of using a transient phase change model in the current case is to simulate the dynamics and geometry of a growing laser-cutting generated kerf until it becomes fully developed. The model is used to investigate the effect of some process parameters on temperature fields and the formed kerf geometry.

Keywords: laser cutting, numerical simulation, heat transfer, fluid flow

Procedia PDF Downloads 339

Authors: Simin Khodabakhshi, Hossein Rassi

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Hyperlipidemia refers to any of several acquired or genetic disorders that result in a high level of lipids circulating in the blood. Helicobacter pylori infection is a contributing factor in the progression of hyperlipidemia with serum lipid changes. The aim of this study was to detect of Helicobacter pylori by PCR and serological methods in patients with hyperlipidemia. In this case-control study, 174 patients with hyperlipidemia and 174 healthy controls were studied. Also, demographics, physical and biochemical parameters were performed in all samples. The DNA extracted from blood specimens was amplified by H pylori cagA specific primers. The results show that H. pylori cagA positivity was detected in 79% of the hyperlipidemia and in 56% of the control group by ELISA test and 49% of the hyperlipidemia and in 24% of the control group by PCR test. Prevalence of H. pylori infection was significantly higher in hyperlipidemia as compared to controls. In addition, patients with hyperlipidemia had significantly higher values for triglyceride, total cholesterol, LDL-C, waist to hip ratio, body mass index, diastolic and systolic blood pressure and lower levels of HDL-C than control participants (all p < 0.0001). Our result detected the ELISA was a rapid and cost-effective detection and considering the high prevalence of cytotoxigenic H. pylori strains, cag A is suggested as a promising target for PCR and ELISA tests for detection of infection with toxigenic strains. In general, it can be concluded that molecular analysis of H. pylori cagA and clinical parameters are important in early detection of hyperlipidemia and atherosclerosis with H. pylori infection by PCR and ELISA tests.

Keywords: Helicobacter pylori, hyperlipidemia, PCR, ELISA

Procedia PDF Downloads 199

Authors: Barenten Suciu, Yuya Nakamoto

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Power generation effect, obtained by inserting a piezo- electric sheet in the backlash clearance of a circular arc helical gear, is evaluated. Such type of screw gear is preferred since, in comparison with the involute tooth profile, the circular arc profile leads to reduced stress-concentration effects, and improved life of the piezoelectric film. Firstly, geometry of the circular arc helical gear, and properties of the piezoelectric sheet are presented. Then, description of the test-rig, consisted of a right-hand thread gear meshing with a left-hand thread gear, and the voltage measurement procedure are given. After creating the tridimensional (3D) model of the meshing gears in SolidWorks, they are 3D-printed in acrylonitrile butadiene styrene (ABS) resin. Variation of the generated voltage versus time, during a meshing cycle of the circular arc helical gear, is measured for various values of the center distance. Then, the change of the maximal, minimal, and peak-to-peak voltage versus the center distance is illustrated. Optimal center distance of the gear, to achieve voltage maximization, is found and its significance is discussed. Such results prove that the contact pressure of the meshing gears can be measured, and also, the electrical power can be generated by employing the proposed technique.

Keywords: circular arc helical gear, contact problem, optimal center distance, piezoelectric sheet, power generation

Procedia PDF Downloads 167

Authors: Tan Swee Liang

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This paper studies the two-way relationship between fintech credit and banking efficiency using the Generalized panel Method of Moment (GMM) estimation in structural equation modeling (SEM). Banking system efficiency, defined as its ability to produce the existing level of outputs with minimal inputs, is measured using input-oriented data envelopment analysis (DEA), where the whole banking system of an economy is treated as a single DMU. Banks are considered an intermediary between depositors and borrowers, utilizing inputs (deposits and overhead costs) to provide outputs (increase credits to the private sector and its earnings). Analysis of the interrelationship between fintech credit and bank efficiency is conducted to determine the impact in different country groupings (ASEAN, Asia and OECD), in particular the banking system response to fintech credit platforms. Our preliminary results show that banks do respond to the greater pressure caused by fintech platforms to enhance their efficiency, but differently across the different groups. The author’s earlier research on ASEAN-5 high bank overhead costs (as a share of total assets) as the determinant of economic growth suggests that expenses may not have been channeled efficiently to income-generating activities. One practical implication of the findings is that policymakers should enable alternative financing, such as fintech credit, as a warning or encouragement for banks to improve their efficiency.

Keywords: fintech lending, banking efficiency, data envelopment analysis, structural equation modeling

Procedia PDF Downloads 91

Authors: Foad Vashahi, Shahnaz Rezaei, Jeekeun Lee

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Large Eddy Simulation (LES) was performed on a dual counter rotating axial swirler in a confined rectangular configuration. Grids were constructed based on a primary Reynolds Averaged Navier-Stokes (RANS) simulation and then were refined based on the Kolmogorov length scale. Water as cold flow condition was applied and results were compared via Particle Image Velocimetry (PIV) experimental results. The focus was to investigate the flow behavior within the region before the flare and very close to the exit of the swirler. This region contributes to a highly unsteady flow behavior and requires great attention to enhancing the flame stability in gas turbine combustor and swirl burners. The PVC formation within the central core flow is strongly related to the peaks of pressure or axial velocity spectrum and up to two distinct peaks at the swirler mouth could be observed. Here, spectra analysis in iso-thermal condition inside the swirler where the inner swirler dominates the flow, showed a higher potential of instabilities with three to four distinct peaks where moving forward to the exit of swirler the number of peaks is decreased. In addition to this, the central axis corresponds to no peaks of instabilities while further away in the radial direction, several peaks exist.

Keywords: axial counter rotating swirler, large eddy simulation (LES), precessing vortex core (PVC), power spectral density (PSD)

Procedia PDF Downloads 280

Authors: T. C. Ng, R. Radzi, T. K. Ng, H. C. Chen

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The analgesic effects of lidocaine-bupivacaine block in cats undergoing routine orchiectomy were determined in this controlled, randomized, and blinded study. Twelve cats were randomly assigned to two groups. Cats in local block group received subcutaneous infiltration of 1 mg/kg of 2% lidocaine and 1 mg/kg of 0.5% bupivacaine into the scrotal sac. Cats in control group received equivolume of saline. Both groups were induced with mixture of ketamine (15 mg/kg) and acepromazine (0.1 mg/kg) intramuscularly and maintained on sevoflurane via facemask. Non-invasive blood pressures (BP), heart (HR), and respiratory rate (RR) were measured intra-operatively at specific events. Post-operatively, all cats received meloxicam, 0.2 mg/kg subcutaneously. Pain scores were determined at 4, 8, and 24 hours postoperatively. Mechanical pressure thresholds (MPT) at the perineum and metatarsus were determined at 2, 4, 8, and 24 hours postoperatively. Intra-operatively, the BP and HR tended to be higher in the control group. The increment in HR peaked during traction and autoligation of the spermatic cord in the control group. There was no treatment difference in RR. Post-operatively, pain scores in the group given local blocks were lower than the control group at 4 hour post-operation. There was no treatment difference in the post-operative HR, RR, BP and MPT values. In conclusion, subcutaneous infiltration of lidocaine-bupivacaine into the scrotal sac before orchiectomy improved intra-operative hemodynamic stability and provided better analgesia up to 4 hours post-surgery.

Keywords: analgesia, bupivacaine, cat, lidocaine, local block, orchiectomy

Procedia PDF Downloads 138

Authors: Sirwan Kamal, Hsein Kew, Hamid Jahromi

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This paper reports results of a study conducted to investigate strength, sorptivity, and permeability under pressure of concrete specimens, cured using a water-based curing compound. The specimens are treated with waterproofing admixtures or surface treatments to enhance performance while exposed to water. Four types of concrete specimens were prepared in the laboratory, Portland cement (CEM I), Portland-fly ash (CEM II/A-V), Blast-furnace cement (CEM III) and Portland-silica fume (CEM II/A-D). Concrete cubes were de-molded three hours after casting, and sprayed with a curing compound. Admixtures were added to the mix during batching, whereas surface treatments were applied on concrete after 28 days. Compressive strength test was carried out to assess the efficiency of curing compound to develop required strength. In addition, sorptivity and permeability tests were conducted to evaluate the performance of treated specimens with respect to water ingress. Results show that strength development in specimens cured with curing compound achieved up to 96% and 90% at 7 and 28 days respectively, compared to cubes cured in water. Moreover, specimens treated with waterproofing admixtures or surface treatments materials characterized by hydrophobic impregnation considerably reduced water penetration compared to untreated control cubes. On the other hand, cubes treated with admixtures or surface treatments materials characterized by crystalline effect were ineffective in reducing water penetration.

Keywords: admixtures, concrete, curing compound, surface treatments

Procedia PDF Downloads 131

Authors: Seon Tae Kim, Robert Hegner, Goksel Ozuylasi, Panagiotis Stathopoulos, Eberhard Nicke

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High-temperature heat pumps (HTHP) that can supply heat at temperatures above 200°C can enhance the energy efficiency of industrial processes and reduce the CO₂ emissions connected with the heat supply of these processes. In the current work, the thermodynamic performance of 3 different vapor compression cycles, which use R-718 (water) as a working medium, have been evaluated by using a commercial process simulation tool (EBSILON Professional). All considered cycles use two-stage vapor compression with intercooling between stages. The main aim of the study is to compare different intercooling strategies and study possible heat recovery scenarios within the intercooling process. This comparison has been carried out by computing the coefficient of performance (COP), the heat supply temperature level, and the respective mass flow rate of water for all cycle architectures. With increasing temperature difference between the heat source and heat sink, ∆T, the COP values decreased as expected, and the highest COP value was found for the cycle configurations where both compressors have the same pressure ratio (PR). The investigation on the HTHP capacities with optimized PR and exergy analysis has also been carried out. The internal heat exchanger cycle with the inward direction of secondary flow (IHX-in) showed a higher temperature level and exergy efficiency compared to other cycles. Moreover, the available operating range was estimated by considering mechanical limitations.

Keywords: high temperature heat pump, industrial process, vapor compression cycle, R-718 (water), thermodynamic analysis

Procedia PDF Downloads 149

Authors: H. Noureddine, P. Rao, R. Guru, A. Chandratreya

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The nice guidance for elective total knee replacements states that patients should be given mechanical thrombo-prophylaxis, and if no contraindications chemical thromboprophylaxis in the form of Dabigatran etexilate, Rivaroxiban, UFH, LMWH, or Fondaparinux sodium (CG92, 1.5.14, January 2010). In Practice administering oral agents has been the dominant practice as it reduces the nursing needs, and shortens hospital stay and is generally received better by patients. However, there are well documented associated bleeding risks, and their effects are difficult to reverse in case of major bleeding. Our experience with oral factor 10 inhibitors used for thromboprophylaxis was marked with several patients developing complications necessitating return to the theatre for wound washouts. This has led us to try a different protocol for thromboprophylaxis that we applied on our patients undergoing total and unicondylar knee replacements. We applied mechanical thromboprophylaxis in the form of intermittent pneumatic pressure devices, and chemical thromboprophylaxis in the form of a dose of prophylactic LMWH pre-op, then 150 mg of Aspirin to start 24 hours after the surgery and to continue for 6 weeks, alongside GI cover with PPIs or antihistamines. We also administered local anaesthetics intra-operatively in line with the ERAS protocol thus encouraging early mobilization. We have identified a cohort of 133 patients who underwent one of the aforementioned procedures in the same trust, and by the same surgeon, where this protocol was applied and examined their medical notes retrospectively with a mean follow-up period of 14 months, to identify the rate and percentage of patients who had thrombo-embolic events in the post-operative period.

Keywords: aspirin, heparin, knee arthroplasty, thromboprophylaxis

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Authors: Irati Barandiaran, Xabier Velasco-Iza, Galder Kortaberria

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Hybrid inorganic/organic nanostructured materials based on block copolymers are of considerable interest in the field of Nanotechnology, taking into account that these nanocomposites combine the properties of polymer matrix and the unique properties of the added nanoparticles. The use of block copolymers as templates offers the opportunity to control the size and the distribution of inorganic nanoparticles. This research is focused on the surface modification of inorganic nanoparticles to reach a good interface between nanoparticles and polymer matrices which hinders the nanoparticle aggregation. The aim of this work is to obtain a good and selective dispersion of Fe3O4 magnetic nanoparticles into different types of block copolymers such us, poly(styrene-b-methyl methacrylate) (PS-b-PMMA), poly(styrene-b-ε-caprolactone) (PS-b-PCL) poly(isoprene-b-methyl methacrylate) (PI-b-PMMA) or poly(styrene-b-butadiene-b-methyl methacrylate) (SBM) by using different grafting strategies. Fe3O4 magnetic nanoparticles have been surface-modified with polymer or block copolymer brushes following different grafting methods (grafting to, grafting from and grafting through) to achieve a selective location of nanoparticles into desired domains of the block copolymers. Morphology of fabricated hybrid nanocomposites was studied by means of atomic force microscopy (AFM) and with the aim to reach well-ordered nanostructured composites different annealing methods were used. Additionally, nanoparticle amount has been also varied in order to investigate the effect of the nanoparticle content in the morphology of the block copolymer. Nowadays different characterization methods were using in order to investigate magnetic properties of nanometer-scale electronic devices. Particularly, two different techniques have been used with the aim of characterizing synthesized nanocomposites. First, magnetic force microscopy (MFM) was used to investigate qualitatively the magnetic properties taking into account that this technique allows distinguishing magnetic domains on the sample surface. On the other hand, magnetic characterization by vibrating sample magnetometer and superconducting quantum interference device. This technique demonstrated that magnetic properties of nanoparticles have been transferred to the nanocomposites, exhibiting superparamagnetic behavior similar to that of the maghemite nanoparticles at room temperature. Obtained advanced nanostructured materials could found possible applications in the field of dye-sensitized solar cells and electronic nanodevices.

Keywords: atomic force microscopy, block copolymers, grafting techniques, iron oxide nanoparticles

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Authors: Xinyue Ma, Dishen Zhang, Yijun Liu, Yutian Jiang, Huiyan Yu, Chufeng Gu

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Conformity is defined as one in a social group changing his or her behavior to match the others’ behavior in the group. It is used to find that people show a higher level of online conformity behavior than offline. However, as anonymity can decrease the level of online conformity behavior, the difference between online and offline conformity behavior among Chinese college students still needs to be tested. In this study, college students (N = 60) have been randomly assigned into three groups: control group, offline experimental group, and online experimental group. Through comparing the results of offline experimental group and online experimental group with the Mann-Whitney U test, this study verified the results of Asch’s experiment, and found out that people show a lower level of online conformity behavior than offline, which contradicted the previous finding found in China. These results can be used to explain why some people make a lot of vicious remarks and radical ideas on the Internet but perform normally in their real life: the anonymity of the network makes the online group pressure less than offline, so people are less likely to conform to social norms and public opinions on the Internet. What is more, these results support the importance and relevance of online voting, because fewer online group pressures make it easier for people to expose their true ideas, thus gathering more comprehensive and truthful views and opinions.

Keywords: anonymity, Asch’s group conformity, Chinese college students, online conformity

Procedia PDF Downloads 152

Authors: Fitri D. Jaswar, Tharek A. Rahman, Yasser A. Ahmad

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CubeSat in low earth orbit (LEO) mainly uses ultra high frequency (UHF) transmitter with fixed radio frequency (RF) output power to download the telemetry and the payload data. The transmitter consumes large amount of electrical energy during the transmission considering the limited satellite size of a CubeSat. A transmitter with power control ability is designed to achieve optimize the signal to noise ratio (SNR) and efficient power consumption. In this paper, the thermal vacuum chamber (TVAC) test is performed to validate the performance of the UHF band transmitter with power control capability. The TVAC is used to simulate the satellite condition in the outer space environment. The TVAC test was conducted at the Laboratory of Spacecraft Environment Interaction Engineering, Kyushu Institute of Technology, Japan. The TVAC test used 4 thermal cycles starting from +60°C to -20°C for the temperature setting. The pressure condition inside chamber was less than 10-5Pa. During the test, the UHF transmitter is integrated in a CubeSat configuration with other CubeSat subsystem such as on board computer (OBC), power module, and satellite structure. The system is validated and verified through its performance in terms of its frequency stability and the RF output power. The UHF band transmitter output power is tested from 0.5W to 2W according the satellite mode of operations and the satellite power limitations. The frequency stability is measured and the performance obtained is less than 2 ppm in the tested operating temperature range. The test demonstrates the RF output power is adjustable in a thermal vacuum condition.

Keywords: communication system, CubeSat, SNR, UHF transmitter

Procedia PDF Downloads 264

Authors: Apostolos Lagarias, Anastasia Stratigea

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Coastal urbanization is heavily affecting the Mediterranean, taking the form of linear urban sprawl along the coastal zone. This process is posing extreme pressure on ecosystems, leading to an unsustainable model of growth. The aim of this research is to analyze coastal urbanization patterns in the Mediterranean using High-resolution multi-temporal data provided by the Global Human Settlement Layer (GHSL) database. Methodology involves the estimation of a set of spatial metrics characterizing the density, aggregation/clustering and dispersion of built-up areas. As case study areas, the Spanish Coast and the Adriatic Italian Coast are examined. Coastalization profiles are examined and selected sub-areas massively affected by tourism development and suburbanization trends (Costa Blanca/Murcia, Costa del Sol, Puglia, Emilia-Romagna Coast) are analyzed and compared. Results show that there are considerable differences between the Spanish and the Italian typologies of spatial development, related to the land use structure and planning policies applied in each case. Monitoring and analyzing spatial patterns could inform integrated Mediterranean strategies for coastal areas and redirect spatial/environmental policies towards a more sustainable model of growth

Keywords: coastalization, Mediterranean, multi-temporal, urban sprawl, spatial metrics

Procedia PDF Downloads 138

Authors: Ibrahim Abouelkhir

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Background: Prior to this project, the number of CT aorta requests from our Emergency Department (ED) was reported by the radiology department to be high with a low positive event rate: only 1- 2% of CT aortas performed were positive for acute aortic syndrome. This trend raised concerns about the time required to process and report these scans, potentially impacting the timely reporting of other high-priority imaging, such as trauma-related scans. Other harms identified were unnecessary radiation, patients spending longer in ED contributing to overcrowding, and, most importantly, the patient not getting the right care the first time. The radiology department also raised the problem of reporting bias because they expected our CT aortas to be normal. Aim: The main aim of this project was to reduce the number of unnecessary CT aortas requested, which would be shown by 1. Number of CT aortas requested and 2. Positive event rate. Methodology: This was a quality improvement project carried out in the ED at Frimley Park Hospital, UK. Starting from 1 st January 2024, we recorded the number of days required to reach 35 CT aorta requests. We looked at all patients presenting to the ED over the age of 16 for whom a CT aorta was requested by the ED team. We looked at how many of these scans were positive for acute aortic syndrome. The intervention was a change in practice: all CT aortas should be approved by an ED consultant or ST4+ registrar (5th April 2024). We then reviewed the number of days it took to reach a total of 35 CT aorta requests following the intervention and again reviewed how many were positive. Results: Prior to the intervention, 35 CT Aorta scans were performed over a 20-day period. Following the implementation of the ED senior doctor vetting process, the same number of CT Aorta scan requests was observed over 50 days - more than twice the pre-intervention period. This indicates a significant reduction in the rate of CT Aorta scans being requested. During the pre-intervention phase, there were two positive cases of acute aortic syndrome. In the post-intervention period, there were zero. Conclusion: The mandatory review of CT Aorta scan requested by the ED consultant effectively reduced the number of scans requested. However, this intervention did not lead to an increase in positive scan results. We noted that post-intervention, approximately 50% of scans had been approved by registrar-grade doctors and, only 50% had been approved by ED consultants, and the majority were not in-person reviews. We wonder if restricting the approval to consultant grade only might improve the results, and furthermore, in person reviews should be the gold standard.

Keywords: quality improvement project, CT aorta scans, emergency department, radiology department, aortic dissection, scan request vetting, clinical outcomes, imaging efficiency

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Authors: Waleed Jarjoura

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In various cases of visual impairments, the individuals are referred to expert Ophthalmologists in order to establish a correct diagnosis. Children with visual-impairments confront various challenging experiences in life since early childhood throughout lifespan. In some cases, blind infants, especially due to congenital hydrocephalus, suffer from high intra-cranial pressure and, consequently, go through a ventriculo-peritoneal shunt surgery in order to limit the neurological symptoms or decrease the cognitive impairments. In this article, a detailed description of numerous crucial implications of the V/P shunt surgery, through the right posterior-inferior parieto-temporal cortex, on the observed preliminary capabilities that are pre-requisites for the acquisition of literacy skills in braille, basic Math competencies, braille printing which suggest Gerstmann syndrome in the blind. In addition, significant difficultiesorientation and mobility skills using the Cane, in general, organizational skills, and social interactions were observed. The primary conclusion of this report focuses on raising awareness among neuro-surgeons towards the need for alternative intracranial routes for V/P shunt implantation in blind infants that preserve the right posterior-inferior parieto-temporal cortex that is hypothesized to modulate the tactual-spatial cues in braille discrimination. A second conclusion targets educators and therapists that address the acquired dysfunctionsin blind individuals due to V/P shunt surgeries.

Keywords: congenital blindness, hydrocephalus, shunt surgery, spatial orientation

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Authors: Alberto Abello Moreno-Cid

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Mummification was the process through which immortality was granted to the deceased, so it was of extreme importance to the Egyptians. The techniques of embalming had evolved over the centuries, and specialists created increasingly sophisticated tools. However, due to its eminently religious nature, knowledge about everything related to this practice was jealously preserved, and the testimonies that have survived to our time are scarce. For this reason, embalming instruments found in archaeological excavations are uncommon. The tomb of the Vizier Amenhotep Huy (AT No. -28-), located in the el-Assasif necropolis that is being excavated since 2009 by the team of the Institute of Ancient Egyptian Studies, has been the scene of some discoveries of this type that evidences the existence of mummification practices in this place after the New Kingdom. The clysters or enemas are the fundamental tools in the second type of mummification described by the historian Herodotus to introduce caustic solutions inside the body of the deceased. Nevertheless, such objects only have been found in three locations: the tomb of Ankh-Hor in Luxor, where a copper enema belonged to the prophet of Ammon Uah-ib-Ra came to light; the excavation of the tomb of Menekh-ib-Nekau in Abusir, where was also found one made of copper; and the excavations in the Bucheum, where two more artifacts were discovered, also made of copper but in different shapes and sizes. Both of them were used for the mummification of sacred animals and this is the reason they vary significantly. Therefore, the object found in the tomb No. -28-, is the first known made of faience of all these peculiar tools and the oldest known until now, dated in the Third Intermediate Period (circa 1070-650 B.C.). This paper bases its investigation on the study of those parallelisms, the material, the current archaeological context and the full analysis and reconstruction of the object in question. The key point is the use of faience in the production of this item: creating a device intended to be in constant use seems to be a first illogical compared to other samples made of copper. Faience around the area of Deir el-Bahari had a strong religious component, associated with solar myths and principles of the resurrection, connected to the Osirian that characterises the mummification procedure. The study allows to refute some of the premises which are held unalterable in Egyptology, verifying the utilization of these sort of pieces, understanding its way of use and showing that this type of mummification was also applied to the highest social stratum, in which case the tools were thought out of an exceptional quality and religious symbolism.

Keywords: clyster, el-Assasif, embalming, faience enema mummification, Theban necropolis

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Authors: Krishnaiah Arkanti, Ramulu Malothu

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The experiments have been conducted to study the mechanical properties of commercially pure copper processing at room temperature by severe plastic deformation using equal channel angular extrusion (ECAE) through a die of 90^oangle up to 3 passes by route B_C i.e. rotating the sample in the same direction by 90^o after each pass. ECAE is used to produce from existing coarse grains to ultra-fine, equiaxed grains structure with high angle grain boundaries in submicron level by introducing a large amount of shear strain in the presence of hydrostatic pressure into the material without changing billet shape or dimension. Mechanical testing plays an important role in evaluating fundamental properties of engineering materials as well as in developing new materials and in controlling the quality of materials for use in design and construction. Yield stress, ultimate tensile stress and ductility are structure sensitive properties and vary with the structure of the material. Microhardness and tensile tests were carried out to evaluate the hardness, strength and ductility of the ECAE processed materials. The results reveal that the strength and hardness of commercially pure copper samples improved significantly without losing much ductility after each pass.

Keywords: equal channel angular extrusion, severe plastic deformation, copper, mechanical properties

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Authors: Ines Vieira, Luisa Faria

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Globally, half of all mental disorders begin by age 14 and the current gap of poorly addressed adolescent mental health has future consequences in adulthood. Schoolwork pressure to achieve good performance in secondary education might lead to lower levels of life satisfaction in youth and individual emotional competencies are crucial in this life stage. The present study aimed to determine how mindfulness relates to school achievements and well-being in adolescence and whether such a relationship might be mediated by emotional intelligence. We also studied the moderation interaction effects of gender and the involvement in non-curricular activities. A sample of 597 Portuguese adolescents aged 15 to 17 years old (N=597; 292 girls; 298 boys), enrolled in secondary education completed self-report measures of mindfulness (CAMM), emotional intelligence (TEIQue-ASF) and well-being (SWLS) in their Portuguese versions. Using SPSS and AMOS, the results were obtained through path analyses and multiple linear regression. A Confirmatory Factor Analysis was also conducted. The correlation coefficients reported a positive and statistically significant relationship between mindfulness, emotional intelligence and well-being. Regression analysis indicated that mindfulness reduced its influence on well-being and on school results when emotional intelligence was added to the model. Overall, our results provided further evidence supporting the development of robust hypotheses by perceiving the relevance of mindfulness and individual emotional competencies to school achievements and well-being in a way of improving adolescents’ health, wellness, and school success.

Keywords: mindfulness, emotional intelligence, well-being, adolescence, school

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Authors: Salihu Abdullahi Galle

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Students' performance in Economics in schools and on standardized exams in Nigeria has been worrying throughout the years, owing to some teachers' use of conventional and lecture teaching methods. Other obstacles include a lack of training, standardized testing pressure, and aversion to change, all of which can have an impact on students' cognitive ability in Economics and future careers. The researchers employed formative evaluation with feedback (FEFB) to support the teaching and learning process by providing constant feedback to both teachers and students. The researchers employed a quasi-experimental research design to examine two teaching methods (FEFB and traditional). The pre-test and post-test interaction effects were evaluated between students in the experimental group (FEFB) and those in the conventional group. The interaction effects of pre-test and post-test on male and female in the two groups were also examined, with 90 participants. The findings show that students exposed to a FEFB-based teaching approach outperform pupils taught in a traditional classroom setting, and there is no gender interaction effect between the two groups. In light of these findings, the researchers urge that Economics teachers employ FEFB during teaching and learning to ensure timely feedback, and that policymakers ensure that Economics teachers receive training and re-training on FEFB approaches.

Keywords: formative evaluation with feedback (FEFB), students, economics achievement, secondary education

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Authors: Ali Haratian, Soroosh Emami Meybodi

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Using viable microbial cultures within hydrocarbon reservoirs so as to the enhancement of oil recovery through metabolic activities is exactly what we recognize as microbial enhanced oil recovery (MEOR). In similar to many other processes in industries, there are some cons and pros following with MEOR. The creation of sulfides such as hydrogen sulfide as a result of injecting the sulfate-containing seawater into hydrocarbon reservoirs in order to maintain the required reservoir pressure leads to production and growth of sulfate reducing bacteria (SRB) approximately near the injection wells, turning the reservoir into sour; however, SRB is not considered as the only microbial process stimulating the formation of sulfides. Along with SRB, thermochemical sulfate reduction or thermal redox reaction (TSR) is also known to be highly effective at resulting in having extremely concentrated zones of ?2S in the reservoir fluids eligible to cause corrosion. Owing to extent of the topic, more information on the formation of ?₂S is going to be put finger on. Besides, confronting the undesirable production of sulfide species in the reservoirs can lead to serious operational, environmental, and financial problems, in particular the transporting pipelines. Consequently, conjuring up reservoir souring control strategies on the way production of oil and gas is the only way to prevent possible damages in terms of environment, finance, and manpower which requires determining the compound’s reactivity, origin, and partitioning behavior. This article is going to provide a comprehensive review of progress made in this field and the possible advent of new strategies in this technologically advanced world of the petroleum industry.

Keywords: corrosion, hydrogen sulfide, NRB, reservoir souring, SRB

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Authors: Selvaprakash Ramalingam, Rabi N. Sahoo, Dharmendra Saraswat, A. Kumar, Rajeev Ranjan, Joydeep Mukerjee, Viswanathan Chinnasamy, K. K. Chaturvedi, Sanjeev Kumar

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Rice is one of the most important staple food crops in the world. Among the various diseases that affect rice crops, rice blast is particularly significant, causing crop yield and economic losses. While the plant has defense mechanisms in place, such as chemical indicators (proteins, salicylic acid, jasmonic acid, ethylene, and azelaic acid) and resistance genes in certain varieties that can protect against diseases, susceptible varieties remain vulnerable to these fungal diseases. Early prediction of rice blast (RB) disease is crucial, but conventional techniques for early prediction are time-consuming and labor-intensive. Hyperspectral remote sensing techniques hold the potential to predict RB disease at its asymptomatic stage. In this study, we aimed to demonstrate the prediction of RB disease at the asymptomatic stage using non-imaging hyperspectral ASD spectroradiometer under controlled laboratory conditions. We applied statistical spectral discrimination theory to identify unknown spectra of M. Oryzae, the fungus responsible for rice blast disease. The infrared (IR) region was found to be significantly affected by RB disease. These changes may result in alterations in the absorption, reflection, or emission of infrared radiation by the affected plant tissues. Our research revealed that the protein spectrum in the IR region is impacted by RB disease. In our study, we identified strong correlations in the region (Amide group - I) around X 1064 nm and Y 1300 nm with the Lambda / Lambda derived spectra methods for protein detection. During the stages when the disease is developing, typically from day 3 to day 5, the plant's defense mechanisms are not as effective. This is especially true for the PB-1 variety of rice, which is highly susceptible to rice blast disease. Consequently, the proteins in the plant are adversely affected during this critical time. The spectral contour plot reveals the highly correlated spectral regions 1064 nm and Y 1300 nm associated with RB disease infection. Based on these spectral sensitivities, we developed new spectral disease indices for predicting different stages of disease emergence. The goal of this research is to lay the foundation for future UAV and satellite-based studies aimed at long-term monitoring of RB disease.

Keywords: rice blast, asymptomatic stage, spectral sensitivity, IR

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Authors: Maryam Panahi

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Background: Adjuvants such as ketamine, promethazine, and paracetamol could bring up patient's satisfaction and control the harmful effects of opioids besides lessening their needed doses, as seen by the fentanyl/paracetamol and fentanyl/ketamine combination before. The current study is headed to compare paracetamol and ketamine, in addition to fentanyl, applied by infusion pumps in order to pain relief following major surgery. Materials and Methods: Through a double-blinded, randomized clinical trial, patients between18 and 65 with elective surgery for tight or leg fractures with ASA Class 1 and 2 referred to a university hospital in Arak, a town in the central region of Iran, were recruited and used infusion pump for their postoperative pain control. The participants were divided into cases and controls regarding using ketamine/fentanyl (KF) or paracetamol/fentanyl (PF) infusion pumps. Results: The mean pain score was a total of 3.87, with the highest value in KF (5.06) and the lowest in PF (4.50) immediately after finishing the surgery and getting conscious when started using an infusion pump. There was no statistical difference between the groups in this regard. Concerning the side effects of the applied medications, blood pressure and heart rate had no differences comparing the groups. Conclusion: This study showed that paracetamol used in infusion pumps could be brilliant in pain control after major surgeries like those done in lower extremities and joint replacement while lessening opioid use. Although paracetamol was more effective than ketamine in the current trial, more qualified studies at bigger sizes and in other fields of surgery besides orthopedic ones would be useful to support the effects if applicable

Keywords: infusion pump, Ketamine, Paracetamol, pain

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Authors: Mohammad Muntasir Maruf, Muhammad Zillur Rahman Khan, Nasim Jahan, Md. Waziul Alam Chowdhury, Satparkash, Md. Nozrul Islam

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Background: Substance use disorders have become a major public health problem in Bangladesh. Objectives: The present study was designed to assess the pattern of substance use and factors related to it among the hospitalized patients. Methods: This was a cross-sectional study. All the patients who were admitted in a private drug de-addiction clinic in the capital city (Dhaka) of Bangladesh during 1 July-31 December, 2013 and diagnosed as a case of substance use disorder by applying Structured Clinical Interview for DSM- Clinician Version were enrolled in the study. Data were collected through face to face interview by a semi-structured questionnaire and the information was complemented by the case-notes. Study subjects were 105 in number. Data analysis was performed using Statistical Package for Social Sciences (SPSS). Results: Most (90.5%) of the respondents were male. The mean age of the respondents was 28.8 (± 8.0) years. Majority (91.4%) were poly-substance users. Most (27.6%) respondents used 3 types of substances. Smoking or inhalation was the route used by most (90.5%) respondents. More than three-fourth (81%) of the respondents used nicotine. Among the other substances, majority (79%) used opiates group, followed by cannabinoids group (55.2%) and alcohol (41%). Curiosity, peer pressure and to have enjoyment or fun were identified as the common reasons for initiating substance use. Conclusions: A high proportion of poly-substance use was found. The study findings would help in management and prevention strategy of substance use in Bangladesh.

Keywords: Bangladesh, de-addiction clinic, poly-substance users, substance use disorder

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