Search results for: directed energy deposition

Authors: Elizaveta Korzhova, Sebastien Deon, Patrick Fievet, Dmitry Lopatin, Oleg Baranov

Abstract:

Filtration with nanoporous ultrafiltration membranes is an attractive option to remove ionic pollutants from contaminated effluents. Unfortunately, commercial membranes are not necessarily suitable for specific applications, and their modification by polymer deposition is a fruitful way to adapt their performances accordingly. Many methods are usually used for surface modification, but a novel technique based on electrospray is proposed here. Various quantities of polymers were deposited on a commercial membrane, and the impact of the deposit is investigated on filtration performances and discussed in terms of charge and hydrophobicity. The electrospray deposition is a technique which has not been used for membrane modification up to now. It consists of spraying small drops of polymer solution under a high voltage between the needle containing the solution and the metallic support on which membrane is stuck. The advantage of this process lies in the small quantities of polymer that can be coated on the membrane surface compared with immersion technique. In this study, various quantities (from 2 to 40 μL/cm²) of solutions containing two charged polymers (13 mmol/L of monomer unit), namely polyethyleneimine (PEI) and polystyrene sulfonate (PSS), were sprayed on a negatively charged polyethersulfone membrane (PLEIADE, Orelis Environment). The efficacy of the polymer deposition was then investigated by estimating ion rejection, permeation flux, zeta-potential and contact angle before and after the polymer deposition. Firstly, contact angle (θ) measurements show that the surface hydrophilicity is notably improved by coating both PEI and PSS. Moreover, it was highlighted that the contact angle decreases monotonously with the amount of sprayed solution. Additionally, hydrophilicity enhancement was proved to be better with PSS (from 62 to 35°) than PEI (from 62 to 53°). Values of zeta-potential (ζ were estimated by measuring the streaming current generated by a pressure difference on both sides of a channel made by clamping two membranes. The ζ-values demonstrate that the deposits of PSS (negative at pH=5.5) allow an increase of the negative membrane charge, whereas the deposits of PEI (positive) lead to a positive surface charge. Zeta-potentials measurements also emphasize that the sprayed quantity has little impact on the membrane charge, except for very low quantities (2 μL/m²). The cross-flow filtration of salt solutions containing mono and divalent ions demonstrate that polymer deposition allows a strong enhancement of ion rejection. For instance, it is shown that rejection of a salt containing a divalent cation can be increased from 1 to 20 % and even to 35% by deposing 2 and 4 μL/cm² of PEI solution, respectively. This observation is coherent with the reversal of the membrane charge induced by PEI deposition. Similarly, the increase of negative charge induced by PSS deposition leads to an increase of NaCl rejection from 5 to 45 % due to electrostatic repulsion of the Cl- ion by the negative surface charge. Finally, a notable fall in the permeation flux due to the polymer layer coated at the surface was observed and the best polymer concentration in the sprayed solution remains to be determined to optimize performances.

Keywords: ultrafiltration, electrospray deposition, ion rejection, permeation flux, zeta-potential, hydrophobicity

Procedia PDF Downloads 162

Authors: Sujit Kumar Guchhait, Subir Paul

Abstract:

One of the major research areas is to find an alternative source of energy to fulfill the energy crisis and environmental problems. The Fuel cell is such kind of energy producing unit. Use of fuel cell to produce renewable energy for commercial purpose is limited by the high cost of Pt based electrode material. Development of high energetic, as well as inexpensive fuel cell electrode materials, is needs of hour to produce clean energy using derive bio-fuel. In this present investigation, inexpensive Cu-Ni-CeO2 electrode material has been synthesized by using pulse current. The surface morphology of the electrode materials is controlled by several deposition parameters to increase the rate of electrochemical oxidation of alcoholic fuel, ethanol. The electrochemical characterization of the developed material was done by Cyclic Voltammetry (CV) and Chronoamperometry (CA) and Electrochemical Impedance Spectroscopy test. It is interesting to find that both these materials have shown high electrocatalytic properties in terms of high exchange current density (I0), low polarization resistance (Rp) and low impedance. It is seen that the addition of CeO2 to Ni-Cu has outperformed Pt as far as high electrocatalytic properties are concerned. The exchange current density on the Cu-Ni-CeO2 electrode surface for ethanol oxidation is about eight times higher than the same on the Pt surface with much lower polarization resistance than the later. The surface morphology of the electrode materials has been revealed by Field Effect Scanning Electron Microscope (FESEM). It is seen that grains are narrow and subspherical with 3D surface containing pores in between two elongated grains. XRD study exhibits the presence of Ni and CeO2 on the Cu surface.

Keywords: electro-catalyst, alcoholic fuel, cyclic voltammetry, potentiodynamic polarization, EIS, XRD, SEM

Procedia PDF Downloads 271

Authors: Brahim Aissa

Abstract:

Transparent conductive oxides (TCOs) used as front electrodes in solar cells must feature simultaneously high electrical conductivity, low contact resistance with the adjacent layers, and an appropriate refractive index for maximal light in-coupling into the device. However, these properties may conflict with each other, motivating thereby the search for TCOs with high performance. Additionally, due to the presence of temperature sensitive layers in many solar cell designs (for example, in thin-film silicon and silicon heterojunction (SHJ)), low-temperature deposition processes are more suitable. Several deposition techniques have been already explored to fabricate high-mobility TCOs at low temperatures, including sputter deposition, chemical vapor deposition, and atomic layer deposition. Among this variety of methods, to the best of our knowledge, magnetron sputtering deposition is the most established technique, despite the fact that it can lead to damage of underlying layers. The Sn doped In₂O₃ (ITO) is the most commonly used transparent electrode-contact in SHJ technology. In this work, we studied the properties of ITO thin films grown by RF sputtering. Using different oxygen fraction in the argon/oxygen plasma, we prepared ITO films deposited on glass substrates, on one hand, and on a-Si (p and n-types):H/intrinsic a-Si/glass substrates, on the other hand. Hall Effect measurements were systematically conducted together with total-transmittance (TT) and total-reflectance (TR) spectrometry. The electrical properties were drastically affected whereas the TT and TR were found to be slightly impacted by the oxygen variation. Furthermore, the time of flight-secondary ion mass spectrometry (TOF-SIMS) technique was used to determine the distribution of various species throughout the thickness of the ITO and at various interfaces. The depth profiling of indium, oxygen, tin, silicon, phosphorous, boron and hydrogen was investigated throughout the various thicknesses and interfaces, and obtained results are discussed accordingly. Finally, the extreme conditions were selected to fabricate rear emitter SHJ devices, and the photovoltaic performance was evaluated; the lower oxygen flow ratio was found to yield the best performance attributed to lower series resistance.

Keywords: solar cell, silicon heterojunction, oxygen content, optoelectronic properties

Procedia PDF Downloads 127

Authors: Jorge Santos, Ana V. Girão, F. J. Oliveira, Alexandre C. Bastos

Abstract:

Protective or decorative coatings containing hexavalent chromium compounds are still used on metal and plastic parts. These hexavalent chromium compounds represent a risk to living beings and the environment, and, for this reason, there is a great need to investigate alternatives. Physical Vapor Deposition (PVD) is an environmentally friendly process that allows the deposition of wear and corrosion resistant thin films with excellent optical properties. However, PVD thin films are porous and if deposited onto low corrosion resistant substrates, lead to a degradation risk. The corrosion behavior of chromium-free electroplated coating systems finished with magnetron sputtered PVD thin films was investigated in this work. The electroplated systems consisted of distinct nickel layers deposited on top of a copper interlayer on acrylonitrile butadiene styrene (ABS) plates. Electrochemical and corrosion evaluation was conducted by electrochemical impedance spectroscopy and polarization curves on the different electroplated coating systems, with and without PVD thin film on top. The results show that the corrosion resistance is lower for the electroplated coating systems finished with PVD thin film for extended exposure periods when compared to those without the PVD overlay.

Keywords: PVD, electroplating, corrosion, thin film

Procedia PDF Downloads 114

Authors: Meftah O. Bashir, Fatma A. Karkory

Abstract:

Rapid prototyping is a new group of manufacturing processes, which allows fabrication of physical of any complexity using a layer by layer deposition technique directly from a computer system. The rapid prototyping process greatly reduces the time and cost necessary to bring a new product to market. The prototypes made by these systems are used in a range of industrial application including design evaluation, verification, testing, and as patterns for casting processes. These processes employ a variety of materials and mechanisms to build up the layers to build the part. The present work was to build a FDM prototyping machine that could control the X-Y motion and material deposition, to generate two-dimensional and three-dimensional complex shapes. This study focused on the deposition of wax material. This work was to find out the properties of the wax materials used in this work in order to enable better control of the FDM process. This study will look at the integration of a computer controlled electro-mechanical system with the traditional FDM additive prototyping process. The characteristics of the wax were also analysed in order to optimize the model production process. These included wax phase change temperature, wax viscosity and wax droplet shape during processing.

Keywords: rapid prototyping, wax, manufacturing processes, shape

Procedia PDF Downloads 439

Authors: Saima Noreen, Malcolm D. MacLeod

Abstract:

Different types of forgiveness (emotional and decisional) have been shown to have differential effects on incidental forgetting of information related to a prior transgression. The present study explored the extent to which emotional and decisional forgiveness also influenced intentional forgetting; that is, the extent to which forgetting occurs following an explicit instruction to forget. Using the List-Method Directed Forgetting (LMDF) paradigm, 236 participants were presented with a hypothetical transgression and then assigned to an emotional forgiveness, a decisional forgiveness, or a no-forgiveness manipulation. Participants were then presented with two-word lists each comprising transgression-relevant and transgression-irrelevant words. Following the presentation of the first list, participants were told to either remember or forget the previously learned list of words. Participants in the emotional forgiveness condition were found to remember fewer relevant and more irrelevant transgression-related words, while the opposite was true for both decisional forgiveness and no-forgiveness conditions. Furthermore, when directed to forget words in List 1, participants in the decisional and no-forgiveness conditions were less able to forget relevant transgression-related words in comparison to participants in the emotional forgiveness condition. This study suggests that emotional forgiveness plays a pivotal role in the intentional forgetting of transgression-related information. The potential implications of these findings for coping with unpleasant incidents will be considered.

Keywords: decisional forgiveness, directed forgetting, emotional forgiveness, executive control, forgiveness

Procedia PDF Downloads 202

Authors: Marzieh Joda, Narges Fallah, Neda Afsham

Abstract:

Graphite-supported two different of morphology α and β -Ni (OH)₂ electrodes were prepared by electrochemical deposition at appropriate potentials with regard to Ni (II)/Ni (III) redox couple under alkaline and acidic conditions, respectively, for selective oxidation of ammonia to nitrogen in the direct electro-oxidation process. Cyclic voltammetry (CV) of the electrolyte containing NH₃ indicated mediation of electron transfer by Ni (OH)₂ and the electrode surface was analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), Raman spectrometer (RS), and X-ray photoelectron spectroscopy (XPS). Results of surface characterization indicated the presence of α polymorphs which is the stable phase of Ni (OH)₂ /Graphite. Cyclic voltammograms gave information on the nature of electron transfer between nitrogen species and working electrode and revealed that the potential has depended on both nature ammonia oxidation and that of concentration. The mechanism of selective ammonia conversion to nitrogen and byproducts, namely NO₂- and NO₃- was established by Cyclic voltammograms and current efficiency. The removal efficiency and selective conversion of ammonia (0.1 M KNO₃ + 0.01 M Ni(NO₃)₂, pH 11, 250°C) on Nickel Oxide-hydroxide /Graphite was determined based on potential controlled experiments.

Keywords: Electro deposition, Nickel oxide-hydroxide, Nitrogen selectivity, Ammonia oxidation

Procedia PDF Downloads 189

Authors: Anis A. Ansari, M. Kamil

Abstract:

The development of 3D printing technology has allowed the manufacturing industry to create parts with a high degree of automation, increased design freedom, and improved mechanical performance. Fused deposition modelling (FDM) is a 3D printing technique in which successive layers of thermoplastic polymer are deposited and controlled to create a three-dimensional product. In this study, process parameters such as nozzle temperature and printing speed were chosen to investigate their effects on hardness properties. 3D printed specimens were fabricated by an FDM 3D printer from Polylactic acid (PLA) polymer. After analysis, it was observed that the hardness property is much influenced by print speed and nozzle temperature parameters. Maximum hardness was achieved at higher print speed which indicates that the Shore D hardness is directly proportional to the print speed. Moreover, at higher print speed, it has no significant dependence on the nozzle temperature. Hardness is also influenced by nozzle temperature, though to a lesser extent. The hardness slightly lowers when the nozzle temperature is raised from 190 to 210 oC, but due to improved bonding between each raster, a further rise in temperature increases the hardness property.

Keywords: 3D printing, fused deposition modeling (FDM), polylactic acid (PLA), print speed, nozzle temperature, hardness property

Procedia PDF Downloads 66

Authors: A. D. Chandio, P. Xiao

Abstract:

In this study, nickel aluminide coatings were deposited onto CMSX-4 single crystal superalloy and pure Ni substrates by using in-situ chemical vapour deposition (CVD) technique. The microstructural evolutions and coating thickness (CT) were studied upon the variation of processing conditions i.e. time and temperature. The results demonstrated (under identical conditions) that coating formed on pure Ni contains no substrate entrapments and have lower CT in comparison to one deposited on the CMSX-4 counterpart. In addition, the interdiffusion zone (IDZ) of Ni substrate is a γ’-Ni3Al in comparison to the CMSX-4 alloy that is βNiAl phase. The higher CT on CMSX-4 superalloy is attributed to presence of γ-Ni/γ’-Ni3Al structure which contains ~ 15 at.% Al before deposition (that is already present in superalloy). Two main deposition parameters (time and temperature) of the coatings were also studied in addition to standard comparison of substrate effects. The coating formation time was found to exhibit profound effect on CT, whilst temperature was found to change coating activities. In addition, the CT showed linear trend from 800 to 1000 °C, thereafter reduction was observed. This was attributed to the change in coating activities.

Keywords: βNiAl, in-situ CVD, CT, CMSX-4, Ni, microstructure

Procedia PDF Downloads 205

Authors: Amy Pullen, Samantha Rodrigues, David Kieser, Brian Shaw

Abstract:

The aim of the study was to determine if a projectile interacting with the lungs increases the severity of injury in comparison to a projectile interacting with the ribs or intercostal muscle. This comparative study employed a 10% gelatine based model with either porcine ribs or balloons embedded to represent a lung. Four sample groups containing five samples were evaluated; these were control (plain gel), intercostal impact, rib impact, and lung impact. Two ammunition natures were evaluated at a range of 10m; these were 5.56x45mm and 7.62x51mm. Aspects of projectile behavior were quantified including exiting projectile weight, location of yawing, projectile fragmentation and distribution, location and area of the temporary cavity, permanent cavity formation, and overall energy deposition. Major findings included the cavity showing a higher percentage of the projectile weight exit the block than the intercostal and ribs, but similar to the control for the 5.56mm ammunition. However, for the 7.62mm ammunition, the lung was shown to have a higher percentage of the projectile weight exit the block than the control, intercostal and ribs. The total weight of projectile fragments as a function of penetration depth revealed large fluctuations and significant intra-group variation for both ammunition natures. Despite the lack of a clear trend, both plots show that the lung leads to greater projectile fragments exiting the model. The lung was shown to have a later center of the temporary cavity than the control, intercostal and ribs for both ammunition types. It was also shown to have a similar temporary cavity volume to the control, intercostal and ribs for the 5.56mm ammunition and a similar temporary cavity to the intercostal for the 7.62mm ammunition The lung was shown to leave a similar projectile tract than the control, intercostal and ribs for both ammunition types. It was also shown to have larger shear planes than the control and the intercostal, but similar to the ribs for the 5.56mm ammunition, whereas it was shown to have smaller shear planes than the control but similar shear planes to the intercostal and ribs for the 7.62mm ammunition. The lung was shown to have less energy deposited than the control, intercostal and ribs for both ammunition types. This comparative study provides insights into the influence of the lungs on thoracic gunshot trauma. It indicates that the lungs limits projectile deformation and causes a later onset of yawing and subsequently limits the energy deposited along the wound tract creating a deeper and smaller cavity. This suggests that lung impact creates an altered pattern of local energy deposition within the target which will affect the severity of trauma.

Keywords: ballistics, lung, trauma, wounding

Procedia PDF Downloads 141

Authors: Shilpesh R. Rajpurohit, Harshit K. Dave

Abstract:

Additive manufacturing gains the popularity in recent times, due to its capability to create prototype as well functional as end use product directly from CAD data without any specific requirement of tooling. Fused deposition modeling (FDM) is one of the widely used additive manufacturing techniques that are used to create functional end use part of polymer that is comparable with the injection-molded parts. FDM printed part has an application in various fields such as automobile, aerospace, medical, electronic, etc. However, application of FDM part is greatly affected by poor mechanical properties. Proper selection of the process parameter could enhance the mechanical performance of the printed part. In the present study, experimental investigation has been carried out to study the behavior of the mechanical performance of the printed part with respect to process variables. Three process variables viz. raster angle, raster width and layer height have been varied to understand its effect on tensile strength. Further, effect of process variables on fractured surface has been also investigated.

Keywords: 3D Printing, fused deposition modeling, layer height, raster angle, raster width, tensile strength

Procedia PDF Downloads 175

Authors: Aigerim Uyzbayeva, Valeriya Tyo, Nurlan Ibrayev

Abstract:

Kazakhstan is currently one of the dynamically developing states in its region. The stable growth in all sectors of the economy leads to a corresponding increase in energy consumption. Thus, country consumes a significant amount of energy due to the high level of industralisation and the presence of energy-intensive manufacturing such as mining and metallurgy which in turn leads to low energy efficiency. With allowance for this the Government has set several priorities to adopt a transition of Republic of Kazakhstan to a “green economy”. This article provides an overview of Kazakhstan’s energy efficiency situation in for the period of 1991-2014. First, the dynamics of production and consumption of conventional energy resources are given. Second, the potential of renewable energy sources is summarised, followed by the description of GHG emissions trends in the country. Third, Kazakhstan’ national initiatives, policies and locally implemented projects in the field of energy efficiency are described.

Keywords: energy efficiency in Kazakhstan, greenhouse gases, renewable energy, sustainable development

Procedia PDF Downloads 557

Authors: Fahim Ullah, Muhammad Usman

Abstract:

Energy consumption and environmental sustainability are hard challenges of 21st century. Energy richness increases environmental pollution while energy poverty hinders economic growth. Considering these two aspects, present study calculates energy deficiency and examines the role of renewable energy to overcome rising energy deficiency and carbon emission for selected countries from 1990 to 2021. For empirical analysis, this study uses methods of moments panel quantile regression analysis and to check the robustness, study used panel quantile robust analysis. Graphical analysis indicated rising global energy deficiency since last three decades where energy consumption is higher than energy production. Empirical results showed that renewable energy is a significant factor for reducing energy deficiency. Secondly, the energy deficiency increases carbon emission level and again renewable energy decreases emissions level. This study recommends that global energy deficiency and rising carbon emissions can be controlled through structural change in the form of energy transition to replace non-renewable resources with renewable resources.

Keywords: energy deficiency, renewable energy, carbon emission, energy trade, PQL analysis

Procedia PDF Downloads 23

Authors: Michael Shandalov, Tzvi Templeman, Michael Schmidt, Itzhak Kelson, Eyal Yahel

Abstract:

We present a new method to produce a model system for the study of radiation damage in non-radioactive materials. The method is based on homogeneously incorporating 228Th ions in PbS thin films using a small volume chemical bath deposition (CBD) technique. The common way to alloy metals with radioactive elements is by melting pure elements, which requires considerable amounts of radioactive material with its safety consequences such as high sample activity. Controlled doping of the thin films with (very) small amounts (100-200ppm) of radioactive elements such as thorium is expected to provide a unique path for studying radiation damage in materials due to decay processes without the need of sealed enclosure. As a first stage, we developed CBD process for controlled doping of PbS thin films (~100 nm thick) with the stable isotope (t1/2~106 years), 232Th. Next, we developed CBD process for controlled doping of PbS thin films with active 228Th isotope. This was achieved by altering deposition parameters such as temperature, pH, reagent concentrations and time. The 228Th-doped films were characterized using X-ray diffraction, which indicated a single phase material. Film morphology and thickness were determined using scanning electron microscopy (SEM). Energy dispersive spectroscopy (EDS) mapping in the analytical transmission electron microscope (A-TEM), X-ray photoelectron spectroscopy (XPS) depth profiles and autoradiography indicated that the Th ions were homogeneously distributed throughout the films, suggesting Pb substitution by Th ions in the crystal lattice. The properties of the PbS (228Th) film activity were investigated by using alpha-spectroscopy and gamma spectroscopy. The resulting films are applicable for isochronal annealing of resistivity measurements and currently under investigation. This work shows promise as a model system for the analysis of dilute defect systems in semiconductor thin films.

Keywords: thin films, doping, radiation damage, chemical bath deposition

Procedia PDF Downloads 366

Authors: Diana Rymuszka, Konrad Terpiłowski, Lucyna Hołysz, Elena Goncharuk, Iryna Sulym

Abstract:

Superhydrophobic surfaces exhibit extremely high water repellency. The commonly accepted basic criterion for such surfaces is a water contact angle larger than 150°, low contact angle hysteresis and low sliding angle. These surfaces are of special interest, because properties such as anti-sticking, anti-contamination and self-cleaning are expected. These properties are attractive for many applications such as anti-sticking of snow for antennas and windows, anti-biofouling paints for boats, waterproof clothing, self-cleaning windshields for automobiles, dust-free coatings or metal refining. The various methods for the preparation of superhydrophobic surfaces since last two decades have been reported, such as phase separation, electrochemical deposition, template method, plasma method, chemical vapor deposition, wet chemical reaction, sol-gel processing, lithography and so on. The aim of the study was to investigate the influence of modified colloidal silica, used as a filler, on the hydrophobicity of the polymer film deposited on the glass support activated with plasma. On prepared surfaces water advancing (ӨA) and receding (ӨR) contact angles were measured and then their total apparent surface free energy was determined using the contact angle hysteresis approach (CAH). The structures of deposited films were observed with the help of an optical microscope. Topographies of selected films were also determined using an optical profilometer. It was found that plasma treatment influence glass surface wetting and energetic properties that is observed in higher adhesion between polymer/filler film and glass support. Using the colloidal silica particles as a filler for the polymer thin film deposited on the glass support, it is possible to produce strongly adhering layers of superhydrophobic properties. The best superhydrophobic properties were obtained for surfaces of the film glass/polimer + modified silica covered in 89 and 100%. The advancing contact angle measured on these surfaces amounts above 150° that leads to under 2 mJ/m2 value of the apparent surface free energy. Such films may have many practical applications, among others, as dust-free coatings or anticorrosion protection.

Keywords: contact angle, plasma, superhydrophobic, surface free energy

Procedia PDF Downloads 450

Authors: J. Tirano, H. Zea, C. Luhrs

Abstract:

It is well known that titanium dioxide is a semiconductor with several applications in photocatalytic process. Its band gap makes it very interesting in the photoelectrodes manufacturing used in photoelectrochemical cells for hydrogen production, a clean and environmentally friendly fuel. The synthesis of 1D titanium dioxide nanostructures, such as nanotubes, makes possible to produce more efficient photoelectrodes for solar energy to hydrogen conversion. In essence, this is because it increases the charge transport rate, decreasing recombination options. However, its principal constraint is to be mainly sensitive to UV range, which represents a very low percentage of solar radiation that reaches earth's surface. One of the alternatives to modifying the TiO2’s band gap and improving its photoactivity under visible light irradiation is to dope the nanotubes with transition metals. This option requires fabricating efficient nanostructured photoelectrodes with controlled morphology and specific properties able to offer a suitable surface area for metallic doping. Hence, currently one of the central challenges in photoelectrochemical cells is the construction of nanomaterials with a proper band position for driving the reaction while absorbing energy over the VIS spectrum. This research focuses on the synthesis and characterization of Nidoped TiO2 nanotubes for improving its photocatalytic activity in solar energy conversion applications. Initially, titanium dioxide nanotubes (TNTs) with controlled morphology were synthesized by two-step potentiostatic anodization of titanium foil. The anodization was carried out at room temperature in an electrolyte composed of ammonium fluoride, deionized water and ethylene glycol. Consequent thermal annealing of as-prepared TNTs was conducted in the air between 450 °C - 550 °C. Afterwards, the nanotubes were superficially modified by nickel deposition. Morphology and crystalline phase of the samples were carried out by SEM, EDS and XRD analysis before and after nickel deposition. Determining the photoelectrochemical performance of photoelectrodes is based on typical electrochemical characterization techniques. Also, the morphological characterization associated electrochemical behavior analysis were discussed to establish the effect of nickel nanoparticles modification on the TiO2 nanotubes. The methodology proposed in this research allows using other transition metal for nanotube surface modification.

Keywords: dimensionally stable electrode, nickel nanoparticles, photo-electrode, TiO₂ nanotubes

Procedia PDF Downloads 151

Authors: Tahereh Talebi, Reza Ghomashchi, Pejman Talemi, Sima Aminorroaya

Abstract:

Electrophoretic deposition (EPD) of p-type Bi₂Te₃ material has been accomplished, and a high quality crack-free thick film has been achieved for thermoelectric (TE) applications. TE generators (TEG) can convert waste heat into electricity, which can potentially solve global warming problems. However, TEG is expensive due to the high cost of materials, as well as the complex and expensive manufacturing process. EPD is a simple and cost-effective method which has been used recently for advanced applications. In EPD, when a DC electric field is applied to the charged powder particles suspended in a suspension, they are attracted and deposited on the substrate with the opposite charge. In this study, it has been shown that it is possible to prepare a TE film using the EPD method and potentially achieve high TE properties at low cost. The relationship between the deposition weight and the EPD-related process parameters, such as applied voltage and time, has been investigated and a linear dependence has been observed, which is in good agreement with the theoretical principles of EPD. A stable EPD suspension of p-type Bi₂Te₃ was prepared in a mixture of acetone-ethanol with triethanolamine as a stabilizer. To achieve a high quality homogenous film on a copper substrate, the optimum voltage and time of the EPD process was investigated. The morphology and microstructures of the green deposited films have been investigated using a scanning electron microscope (SEM). The green Bi₂Te₃ films have shown good adhesion to the substrate. In summary, this study has shown that not only EPD of p-type Bi₂Te₃ material is possible, but its thick film is of high quality for TE applications.

Keywords: electrical conductivity, electrophoretic deposition, mechanical property, p-type Bi2Te3, Seebeck coefficient, thermoelectric materials, thick films

Procedia PDF Downloads 137

Authors: P. Valdez, M. Pelissero, A. Haim, F. Muiño, F. Galia, R. Tula

Abstract:

As a result of the studies performed on the wave energy resource worldwide, a research project was set up to harvest wave energy for its conversion into electrical energy. Within this framework, a theoretical model of the electromechanical energy harvesting system, developed with MATLAB’s Simulink software, will be provided. This tool recreates the site conditions where the device will be installed and offers valuable information about the amount of energy that can be harnessed. This research provides a deeper understanding of the utilization of wave energy in order to improve the efficiency of a 1:1 scale prototype of the device.

Keywords: electromechanical device, modeling, renewable energy, sea wave energy, simulation

Procedia PDF Downloads 454

Authors: András Medve, Katalin Szabad, István Patkó

Abstract:

According to the International Energy Association the previous principles of the energy sector should be reassessed, in which renewable energy sources have a significant role. We might witness the exchange of roles of countries from importer to exporter, which look for the main resources of market needs. According to the World Energy Outlook 2013, the duration of high oil prices is exceptionally long in the history of the energy market. Forecasts also point at the expected great differences between the regional prices of gas and electric energy. The energy need of the world will grow by its third. two thirds of which will appear in China, India, and South-East Asia, while only 4 per cent of which will be related to OECD countries. Current trends also forecast the growth of the price of energy sources and the emission of glasshouse gases. As a reflection of these forecasts alternative energy sources will gain value, of which geothermic energy is one of the cheapest and most economical. Hungary possesses outstanding resources of geothermic energy. The aim of the study is to research the environmental effects of geothermic energy and the opportunities of its exploitation in Hungary, related to „Horizon 2020” project.

Keywords: sustainable energy, renewable energy, development of geothermic energy in Hungary

Procedia PDF Downloads 571

Authors: Hussain Ali Bekhet, Nor Hamisham Harun

Abstract:

The main objective of this paper is to give a comprehensive review of non-renewable energy and renewable energy utilization in Malaysia, including hydropower, solar photovoltaic, biomass and biogas technologies. Malaysia mainly depends on non-renewable energy (natural gas, coal and crude oil) for electricity generation. Therefore, this paper provides a comprehensive review of the energy sector and discusses diversification of electricity generation as a strategy for providing sustainable energy in Malaysia. Energy policies and strategies to protect the non-renewable energy utilization also are highlighted, focusing in the different sources of energy available for high and sustained economic growth. Emphasis is also placed on a discussion of the role of renewable energy as an alternative source for the increase of electricity supply security. It is now evident that to achieve sustainable development through renewable energy, energy policies and strategies have to be well designed and supported by the government, industries (firms), and individual or community participation. The hope is to create a positive impact on sustainable development through renewable sources for current and future generations.

Keywords: Malaysia, non-renewable energy, renewable energy, sustainable energy

Procedia PDF Downloads 365

Authors: Shreya Ghosh, Akansha Garg, Chayanika Kala, Ashwani Kumar Thakur

Abstract:

Background: Granuloma formation is one of the characteristic features of tuberculosis. Besides, chronic inflammation underlying tuberculosis is often indicated by an increase in the concentration of serum amyloid A (SAA) protein. The connection between tuberculosis and SAA-driven secondary amyloidosis is well documented. However, SAA-derived amyloid deposition start sites are not well understood in tuberculosis and other chronic inflammatory conditions. It was hypothesized that granuloma could be a potential site for an amyloid deposition because both SAA protein and proteases that cleave SAA into aggregation-prone fragments are reported to be present in the granuloma. Here the authors have shown the presence of SAA-derived amyloid deposits in the granuloma of tuberculosis patients. Methodology: Over a period of two years, tuberculosis patients were screened, and biopsies were collected from the affected organs of the patients. The gold standard, Congo red dye staining, was used to identify amyloid deposits in the tissue sections of tuberculosis patients containing granulomatous structure. Results: 11 out of 150 FFPE biopsy specimens of tuberculosis patients showed eosinophilic hyaline-rich deposits surrounding granuloma. Upon Congo red staining, these deposits exhibited characteristic apple-green birefringence under polarized light, confirming amyloid deposits. Further, upon immunohistochemical staining with anti-SAA, the amyloid enriched areas showed positive immunoreactivity. Conclusion: In this pilot study, we have shown that granuloma can be a potential site for serum amyloid A-derived amyloid formation in tuberculosis patients. Moreover, the presence of amyloid gave significant cues that granuloma might be a probable amyloid deposition start in tuberculosis patients. This study will set a stage to expand the clinical and fundamental research in the understanding of amyloid formation in granuloma underlying tuberculosis and chronic inflammatory conditions.

Keywords: amyloid, granuloma, periphery, serum amyloid A, tuberculosis

Procedia PDF Downloads 173

Authors: Cyril Agochi Okorowo

Abstract:

More than ever human activity relating to uncontrolled greenhouse gas (GHG) and its effects on the earth is gaining greater attention in the global academic and policy discussions. Activities of man have greatly influenced climate change over the years as a result of a consistent increase in the use of fossil fuel energy. Scientists and researchers globally are making significant and devoted efforts towards the development and implementation of renewable energy technologies that are harmless to the environment. One of such energy is solar energy with its source from the sun. There are currently two primary ways of harvesting this energy from the sun: through photovoltaic (PV) panels and through thermal collectors. This work discusses solar energy as the abundant renewable energy in the tropical Nigeria, processes of harvesting the energy and recommends solar energy as an alternative means of electric power generation in a time the demand for power in Nigeria supersedes supply.

Keywords: analysis, energy, design, solar

Procedia PDF Downloads 259

Authors: Yeo Leng Leng

Abstract:

Blended learning, with its combination of online and face-to-face instruction, presents a unique set of challenges and opportunities in terms of cultivating student agency. While it offers flexibility and personalized learning pathways, it also demands a higher degree of self-regulation and motivation from students. This paper presents the design of blended learning in a Chinese lesson and discusses the framework involved. It also talks about the Edtech tools adopted to engage the students. Some of the students’ works will be showcased. A qualitative case study research method was employed in this paper to find out more about students’ learning experiences and to give them a voice. The purpose is to seek improvement in the blended learning design of the Chinese lessons and to encourage students’ self-directed learning.

Keywords: blended learning, student agency, ed-tech tools, self-directed learning

Procedia PDF Downloads 39

Authors: Vicx Farm

Abstract:

This paper examines the critical role of energy efficiency management and renewable energy in fostering sustainable agricultural practices in Nigeria. With the growing concerns over energy security, environmental degradation, and climate change, there is an urgent need to transition towards more sustainable energy sources and practices in the agricultural sector. Nigeria, being a significant player in the global agricultural market, stands to benefit immensely from integrating energy efficiency measures and renewable energy solutions into its agricultural activities. This paper discusses the current energy challenges facing Nigerian agriculture, explores the potential benefits of energy efficiency and renewable energy adoption, and proposes strategies for effective implementation. The paper concludes with recommendations for policymakers, stakeholders, and practitioners to accelerate the adoption of energy-efficient and renewable energy technologies in Nigerian agriculture, thereby promoting sustainable development and resilience in the sector.

Keywords: energy, agriculture, sustainability, power

Procedia PDF Downloads 33

Authors: Walter M. Millanzi, Stephen M. Kibusi

Abstract:

Background: Currently, there has been a progressive shortage not only to the number but also the quality of medical practitioners for the most of nursing. Despite that, those who are present exhibit unethical and illegal practices, under standard care and malpractices. The concern is raised in the ways they are prepared, or there might be something missing in nursing curricula or how it is delivered. There is a need for transforming or testing new teaching modalities to enhance competent health workforces. Objective: to investigate the Effect of Facilitation in a Problem-based Environment (FPBE) on metacognition, self-directed learning and learning motivation to undergraduate nurse student in Tanzanian higher learning institutions. Methods: quasi-experimental study (quantitative research approach). A purposive sampling technique was employed to select institutions and achieving a sample size of 401 participants (interventional = 134 and control = 267). Self-administered semi-structured questionnaire; was the main data collection methods and the Statistical Package for Service Solution (v. 20) software program was used for data entry, data analysis, and presentations. Results: The pre-post test results between groups indicated noticeably significant change on metacognition in an intervention (M = 1.52, SD = 0.501) against the control (M = 1.40, SD = 0.490), t (399) = 2.398, p < 0.05). SDL in an intervention (M = 1.52, SD = 0.501) against the control (M = 1.40, SD = 0.490), t (399) = 2.398, p < 0.05. Motivation to learn in an intervention (M = 62.67, SD = 14.14) and the control (n = 267, M = 57.75), t (399) = 2.907, p < 0.01). A FPBE teaching pedagogy, was observed to be effective on the metacognition (AOR = 1.603, p < 0.05), SDL (OR = 1.729, p < 0.05) and Intrinsic motivation in learning (AOR = 1.720, p < 0.05) against conventional teaching pedagogy. Needless, was less likely to enhance Extrinsic motivation (AOR = 0.676, p > 0.05) and Amotivation (AOR = 0.538, p > 0.05). Conclusion and recommendation: FPBE teaching pedagogy, can improve student’s metacognition, self-directed learning and intrinsic motivation to learn among nurse students. Nursing curricula developers should incorporate it to produce 21st century competent and qualified nurses.

Keywords: facilitation, metacognition, motivation, self-directed

Procedia PDF Downloads 153

Authors: Hiroko Komatsu, Kaori Yagasaki

Abstract:

Background: Cancer-related cognitive impairment is a common problem seen in cancer patients undergoing chemotherapy. Physical activity may show beneficial effects on the cognitive function in such patients. Therefore, we have developed a self-directed home yoga program for cancer patients with cognitive symptoms during chemotherapy. This program involves a DVD presenting a combination of yoga courses based on patient preferences to be practiced at home. This study was performed to examine the feasibility of this program. In addition, we also examined changes in cognitive function and quality of life (QOL) in these patients participating in the program. Methods: This prospective feasibility study was conducted in a 500-bed general hospital in Tokyo, Japan. The study population consisted of breast cancer patients undergoing chemotherapy as the initial therapy. This feasibility study used a convenience sample with estimation of recruitment rate in a single facility with the availability of trained nurses and physicians to ensure safe yoga intervention. The aim of the intervention program was to improve cognitive function by means of both physical and mental activation via yoga, consisting of physical practice, breathing exercises, and meditation. Information on the yoga program was provided as a booklet, with an instructor-guided group yoga class during the orientation, and a self-directed home yoga program on DVD with yoga logs. Results: The recruitment rate was 44.7%, and the study population consisted of 18 women with a mean age of 43.9 years. This study showed high rates of retention, adherence, and acceptability of the yoga program. Improvements were only observed in the cognitive aspects of fatigue, and there were serious adverse events during the program. Conclusion: The self-directed home yoga program discussed here was both feasible and safe for breast cancer patients showing cognitive symptoms during chemotherapy. The patients also rated the program as useful, interesting, and satisfactory. Participation in the program was associated with improvements in cognitive fatigue but not cognitive function.

Keywords: yoga, cognition, breast cancer, chemotherapy, quality of life

Procedia PDF Downloads 239

Authors: Li Zhu, Binghua Wang, Yong Sun

Abstract:

China is experiencing the rural development process, with the agritourism complex becoming one of the significant modes. Therefore, it is imperative to understand the energy performance of agritourism complex. This study focuses on a typical case of the agritourism complex and simulates the energy consumption performance on condition of the regular energy system. It was found that HVAC took 90% of the whole energy demand range. In order to optimize the energy supply structure, the hierarchical analysis was carried out on the level of architecture with three main factors such as construction situation, building types and energy demand types. Finally, the energy planning suggestion of the agritourism complex was put forward and the relevant results were obtained.

Keywords: agritourism complex, energy planning, energy demand simulation, hierarchical structure model

Procedia PDF Downloads 166

Authors: Temesgen Geremew

Abstract:

ZnS/glass and CdS/glass single layers and ZnS/CdS and CdS/ZnS heterojunction thin films were deposited by the chemical bath deposition method using zinc acetate and cadmium acetate as the metal ion sources and thioacetamide as a nonmetallic ion source in acidic medium. Na2EDTA was used as a complexing agent to control the free cation concentration. +e single layer and heterojunction thin films were characterized with X-ray diffraction (XRD), a scanning electron microscope (SEM), energy dispersive X-ray (EDX), and a UV-VIS spectrometer. +e XRD patterns of the CdS/glass thin film deposited on the soda lime glass substrate crystalized in the cubic structure with a single peak along the (111) plane. +e ZnS/CdS heterojunction and ZnS/glass single layer thin films were crystalized in the hexagonal ZnS structure. +e CdS/ZnS heterojunction thin film is nearly amorphous.The optical analysis results confirmed single band gap values of 2.75 eV and 2.5 eV for ZnS/CdS and CdS/ZnS heterojunction thin films, respectively. +e CdS/glass and CdS/ZnS thin films have more imaginary dielectric components than the real part. The optical conductivity of the single layer and heterojunction films is in the order of 1015 1/s. +e optical study also confirmed refractive index values between 2 and 2.7 for ZnS/glass, ZnS/CdS, and CdS/ZnS thin films for incident photon energies between 1.2 eV and 3.8 eV. +e surface morphology studies revealed compacted spherical grains covering the substrate surfaces with few cracks on ZnS/glass, ZnS/CdS, and CdS/glass and voids on CdS/ZnS thin films. +e EDX result confirmed nearly 1 :1 metallic to nonmetallic ion ratio in the single-layered thin films and the dominance of Zn ion over Cd ion in both ZnS/CdS and CdS/ZnS heterojunction thin films.

Keywords: SERS, sensor, Hg2+, water detection, polythiophene

Procedia PDF Downloads 33

Authors: Yu-Hsuan Liu, Ying-Fang Wang

Abstract:

The objectives of the present study are to characterize nanoparticles generated from the laser metal deposition (LMD) process and to estimate particle concentrations deposited in the head (H), that the tracheobronchial (TB) and alveolar (A) regions, respectively. The studied LMD chamber (3.6m × 3.8m × 2.9m) is installed with a robot laser metal deposition machine. Direct-reading instrument of a scanning mobility particle sizer (SMPS, Model 3082, TSI Inc., St. Paul, MN, USA) was used to conduct static sampling inside the chamber for nanoparticle number concentration and particle size distribution measurements. The SMPS obtained particle number concentration at every 3 minutes, the diameter of the SMPS ranged from 11~372 nm when the aerosol and sheath flow rates were set at 0.6 and 6 L / min, respectively. The resultant size distributions were used to predict depositions of nanoparticles at the H, TB, and A regions of the respiratory tract using the UK National Radiological Protection Board’s (NRPB’s) LUDEP Software. Result that the number concentrations of nanoparticles in indoor background and LMD chamber were 4.8×10³ and 4.3×10⁵ # / cm³, respectively. However, the nanoparticles emitted from the LMD process was in the form of the uni-modal with number median diameter (NMD) and geometric standard deviation (GSD) as 142nm and 1.86, respectively. The fractions of the nanoparticles deposited on the alveolar region (A: 69.8%) were higher than the other two regions of the head region (H: 10.9%), tracheobronchial region (TB: 19.3%). This study conducted static sampling to measure the nanoparticles in the LMD process, and the results show that the fraction of particles deposited on the A region was higher than the other two regions. Therefore, applying the characteristics of nanoparticles emitted from LMD process could be provided valuable scientific-based evidence for exposure assessments in the future.

Keywords: exposure assessment, laser metal deposition process, nanoparticle, respiratory region

Procedia PDF Downloads 263

Authors: Amirhossein Khazali, Mohsen Kalantar

Abstract:

Energy storage units can play an important role to provide an economic and secure operation of future energy systems. In this paper, a stochastic energy and reserve market clearing scheme is presented considering storage energy units. The approach is proposed to deal with stochastic and non-dispatchable renewable sources with a high level of penetration in the energy system. A two stage stochastic programming scheme is formulated where in the first stage the energy market is cleared according to the forecasted amount of wind generation and demands and in the second stage the real time market is solved according to the assumed scenarios.

Keywords: energy and reserve market, energy storage device, stochastic programming, wind generation

Procedia PDF Downloads 545