Search results for: metal free fluorinated phthalocyanine

Authors: Layan Moussa, Darine Salam, Samir Mustapha

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Heavy metal contamination in agricultural soils in Lebanon poses serious environmental and health problems. Intensive efforts are employed to improve existing quantification methods of heavy metals in contaminated environments since conventional detection techniques have shown to be time-consuming, tedious, and costly. The implication of hyperspectral remote sensing in this field is possible and promising. However, factors impacting the efficiency of hyperspectral imaging in detecting and quantifying heavy metals in agricultural soils were not thoroughly studied. This study proposes to assess the use of hyperspectral imaging for the detection of Ni in agricultural clay soil collected from the Bekaa Valley, a major agricultural area in Lebanon, under different contamination levels and soil moisture content. Soil samples were contaminated with Ni, with concentrations ranging from 150 mg/kg to 4000 mg/kg. On the other hand, soil with background contamination was subjected to increased moisture levels varying from 5 to 75%. Hyperspectral imaging was used to detect and quantify Ni contamination in the soil at different contamination levels and moisture content. IBM SPSS statistical software was used to develop models that predict the concentration of Ni and moisture content in agricultural soil. The models were constructed using linear regression algorithms. The spectral curves obtained reflected an inverse correlation between both Ni concentration and moisture content with respect to reflectance. On the other hand, the models developed resulted in high values of predicted R2 of 0.763 for Ni concentration and 0.854 for moisture content. Those predictions stated that Ni presence was well expressed near 2200 nm and that of moisture was at 1900 nm. The results from this study would allow us to define the potential of using the hyperspectral imaging (HSI) technique as a reliable and cost-effective alternative for heavy metal pollution detection in contaminated soils and soil moisture prediction.

Keywords: heavy metals, hyperspectral imaging, moisture content, soil contamination

Procedia PDF Downloads 83

Authors: N. J. Nawarathna, N. R. Kmarasinghe, D. Chandrasekara, B. M. R. S. Balasooriya, R. A. A. Shaminda, R. J. K. Senevirathne

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Introduction: Thyroid malignancy associated with hyperthyroidism is considered rare. Retrospective studies have shown the incidence of thyroid malignancy in hyperthyroid patients to be low (0.7-8.5%). To assess the clinical relevance of this association, thyroid status in a cohort of patients with thyroid malignancy were analyzed. Method: Thyroid malignancies diagnosed histologically in 56 patients, over a 18 month period beginning from April 2013, in a single surgical unit at Teaching Hospital Kandy were included. Preoperative patient details and progression of thyroid status were asessed with Thyroid Stimulating Hormone, free Thyroxin and free Triiodothyronine levels. Results: Amongst 56 patients Papillary carcinoma was diagnosed in 44(78.6%), follicular carcinomas in 7(12.5%) and 5(8.9%) with medullary and anaplastic carcinomas. 12(21.4%) were males and 44(78.6%) were females. 20(35.7%) were less than 40years, 29(51.8%) were between 40 to 59years and 7(12.5%) were above 59years. Cross tabulation of Type of carcinoma with Gender revealed likelihood ratio of 6.908, Significance p = 0.032. Biochemically 12(21.4%) were hyperthyroid. Out of them 5(41.7%) had primary hyperthyroidism and 7(58.3%) had secondary hyperthyroidism. Mean age of euthyroid patients was 43.77years (SD 10.574) and hyperthyroid patients was 53.25years(SD 16.057). Independent Samples Test t is -2.446, two tailed significance p =0.018. When cross tabulate thyroid status with Age group Likelihood Ratio was 9.640, Significance p = 0.008. Conclusion: Papillary carcinoma is seen more among females. Among the patients with thyroid carcinomas, those with biochemically proven hyperthyroidism were more among the older age group than those who were euthyroid. Hence careful evaluation of elderly hyperthyroid patients to select the most suitable therapeutic approach is justified.

Keywords: age, hyperthyroidism, thyroid malignancy, thyroid status

Procedia PDF Downloads 386

Authors: Aurelien Boutin

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In optical systems such as Variable Optical Delay Lines, where a collimated beam has to go back and forth, corner cubes are used in order to keep the reflected beam parallel to the incoming beam. However, the reflected beam can be laterally shifted, which will lead to losses. In this paper, we report on a patented optical design that allows keeping the reflected beam with the exact same position and direction whatever the displacement of the corner cube leading to zero losses. After explaining how the optical design works and theoretically allows to compensate for any defects in the translation of the corner cube, we will present the results of experimental comparisons between a standard layout (i.e., only corner cubes) and our optical layout. To compare both optical layouts, we used a fiber-to-fiber coupling setup. It consists of a couple of lights from one fiber to the other, thanks to two lenses. The ensemble [fiber+lense] is fixed and called a collimator so that the light is coupled from one collimator to another. Each collimator was precisely made in order to have a precise working distance. In the experiment, we measured and compared the Insertion Losses (IL) variations between both collimators with the distance between them (i.e., natural Gaussian beam coupling losses) and between both collimators in the different optical layouts tested, with the same optical length propagation. We will show that the IL variations of our setup are less than 0.05dB with respect to the IL variations of collimators alone.

Keywords: free-space optics, variable optical delay lines, optical cavity, auto-alignment

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Authors: Angélique Laurent, Marie-Josée Letarte, Jean-Pascal Lemelin, Marie-France Morin

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This study aims at exploring teacher-child interactions within learning contexts in public prekindergartens of the province of Québec (Canada). It is based on previous research showing that teacher-child interactions in preschools have direct and determining effects on the quality of early childhood education and could directly or indirectly influence child development. However, throughout a typical preschool day, children experience different learning contexts to promote their learning opportunities. Depending on these specific contexts, teacher-child interactions could vary, for example, between free play and shared book reading. Indeed, some studies have found that teacher-directed or child-directed contexts might lead to significant variations in teacher-child interactions. This study drew upon both the bioecological and the Teaching Through Interactions frameworks. It was conducted through a descriptive and correlational design. Fifteen teachers were recruited to participate in the study. At Time 1 in October, they completed a diary to report the learning contexts they proposed in their classroom during a typical week. At Time 2, seven months later (May), they were videotaped three times in the morning (two weeks’ time between each recording) during a typical morning class. The quality of teacher-child interactions was then coded with the Classroom Assessment Scoring System (CLASS) through the contexts identified. This tool measures three main domains of interactions: emotional support, classroom organization, and instruction support, and10 dimensions scored on a scale from 1 (low quality) to 7 (high quality). Based on the teachers’ reports, five learning contexts were identified: 1) shared book reading, 2) free play, 3) morning meeting, 4) teacher-directed activity (such as craft), and 5) snack. Based on preliminary statistical analyses, little variation was observed within the learning contexts for each domain of the CLASS. However, the instructional support domain showed lower scores during specific learning contexts, specifically free play and teacher-directed activity. Practical implications for how preschool teachers could foster specific domains of interactions depending on learning contexts to enhance children’s social and academic development will be discussed.

Keywords: teacher practices, teacher-child interactions, preschool education, learning contexts, child development

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Authors: Samson Mil'shtein, Dhawal Asthana, Benjamin Sullivan

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The wide energy gap of GaN is the major parameter justifying the design and fabrication of high-power electronic components made of this material. However, the existence of a piezo-electrics in nature sheet charge at the AlGaN/GaN interface complicates the control of carrier injection into the intrinsic channel of GaN HEMTs (High Electron Mobility Transistors). As a result, most of the transistors created as R&D prototypes and all of the designs used for mass production are D-mode devices which introduce challenges in the design of integrated circuits. This research presents the design and modeling of an E-mode GaN HEMT with a very low turn-on voltage. The proposed device includes two critical elements allowing the transistor to achieve zero conductance across the channel when Vg = 0V. This is accomplished through the inclusion of an extremely thin, 2.5nm intrinsic Ga₀.₇₄Al₀.₂₆N spacer layer. The added spacer layer does not create piezoelectric strain but rather elastically follows the variations of the crystal structure of the adjacent GaN channel. The second important factor is the design of a gate metal with a high work function. The use of a metal gate with a work function (Ni in this research) greater than 5.3eV positioned on top of n-type doped (Nd=10¹⁷cm⁻³) Ga₀.₇₄Al₀.₂₆N creates the necessary built-in potential, which controls the injection of electrons into the intrinsic channel as the gate voltage is increased. The 5µm long transistor with a 0.18µm long gate and a channel width of 30µm operate at Vd=10V. At Vg =1V, the device reaches the maximum drain current of 0.6mA, which indicates a high current density. The presented device is operational at frequencies greater than 10GHz and exhibits a stable transconductance over the full range of operational gate voltages.

Keywords: compound semiconductors, device modeling, enhancement mode HEMT, gallium nitride

Procedia PDF Downloads 248

Authors: V. P. Borker, K. S. Rane, A. J. Bhobe, R. S. Karmali

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Effluent of dye industries contains chemicals and organic dyes. Sometimes they are thrown in the water bodies without any treatment. This leads to environmental pollution and is detrimental to flora and fauna. Semiconducting oxide zinc oxide with wide bandgap 3.37 eV is used as a photocatalyst in degrading organic dyes using UV radiations. It generates electron-hole pair on exposure to UV light. If degradation is aimed at solar radiations, bandgap of zinc oxide is to be reduced so as to utilize visible radiation. Thus, in present study, zinc oxide, ZnO is synthesized from zinc oxalate, N doped zinc oxide, ZnO₁₋ₓNₓ from hydrazinated zinc oxalate, cadmium doped zinc oxide Zn₀.₉Cd₀.₁₀ and magnesium-doped zinc oxide Zn₀.₉Mg₀.₁₀ from mixed metal oxalate and hydrazinated mixed metal oxalate. The precursors were characterized by FTIR. They were decomposed to form oxides and XRD were recorded. The compounds were monophasic. Bandgap was calculated using Diffuse Reflectance Spectrum. The bandgap of ZnO was reduced to 3.24 because of precursor method of synthesis leading large surface area. The bandgap of Zn₀.₉Cd₀.₁₀ was 3.11 eV and that of Zn₀.₉Mg₀.₁₀ 3.41 eV. The lowest value was of ZnO₁₋ₓNₓ 3.09 eV. These oxides were used to degrade methylene blue, a model dye in sunlight. ZnO₁₋ₓNₓ was also used to degrade effluent of industry manufacturing colours, crayons and markers. It was observed that ZnO₁₋ₓNₓ acts as a good photocatalyst for degradation of methylene blue. It can degrade the solution within 120 minutes. Similarly, diluted effluent was decolourised using this oxide. Some colours were degraded using ZnO. Thus, the use of these two oxides could mineralize effluent. Lesser bandgap leads to more electro hole pair thus helps in the formation of hydroxyl ion radicals. These radicals attack the dye molecule, fragmentation takes place and it is mineralised.

Keywords: cadmium doped zinc oxide, dye degradation, dye effluent degradation, N doped zinc oxide, zinc oxide

Procedia PDF Downloads 151

Authors: Vidula Shevade, B. J. Nagare, Sajeev Chacko

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First principles simulation, meaning density functional theory (DFT) calculations with plane waves and pseudopotential, has become a prized technique in condensed matter theory. Nanoparticles (NP) have been known to possess good catalytic activities, especially for molecules such as CO, O₂, etc. Among the metal NPs, Aluminium based NPs are also widely known for their catalytic properties. Aluminium metal is a lightweight, excellent electrical, and thermal abundant chemical element in the earth’s crust. Aluminium NPs, when added to solid rocket fuel, help improve the combustion speed and considerably increase combustion heat and combustion stability. Adding aluminium NPs into normal Al/Al₂O₃ powder improves the sintering processes of the ceramics, with high heat transfer performance, increased density, and enhanced thermal conductivity of the sinter. We used VASP and Gaussian 0₃ package to compute the geometries, electronic structure, and bonding properties of Al₁₂Ni as well as its interaction with O₂ and CO molecules. Several MD simulations were carried out using VASP at various temperatures from which hundreds of structures were optimized, leading to 24 unique structures. These structures were then further optimized through a Gaussian package. The lowest energy structure of Al₁₂Ni has been reported to be a singlet. However, through our extensive search, we found a triplet state to be lower in energy. In our structure, the Ni atom is found to be on the surface, which gives the non-zero magnetic moment. Incidentally, O2 and CO molecules are also triplet in nature, due to which the Al₁₂-Ni cluster is likely to facilitate the oxidation process of the CO molecule. Our results show that the most favourable site for the CO molecule is the Ni atom and that for the O₂ molecule is the Al atom that is nearest to the Ni atom. Al₁₂Ni-O₂ and Al₁₂-Ni-CO structures we extracted using VMD. Al₁₂Ni nanocluster, due to in triplet electronic structure configuration, indicates it to be a potential candidate as a catalyst for oxidation of CO molecules.

Keywords: catalyst, gaussian, nanoparticles, oxidation

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Authors: Eqqab Maree, Habil Jurgen Bast, Zana K. Shakir

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Passive damping, once properly characterized and incorporated into the structure design is an autonomous mechanism. Passive damping can be achieved by applying layers of a polymeric material, called viscoelastic layers (VEM), to the base structure. This type of configuration is known as free or unconstrained layer damping treatment. A shear or constrained damping treatment uses the idea of adding a constraining layer, typically a metal, on top of the polymeric layer. Constrained treatment is a more efficient form of damping than the unconstrained damping treatment. In constrained damping treatment a sandwich is formed with the viscoelastic layer as the core. When the two outer layers experience bending, as they would if the structure was oscillating, they shear the viscoelastic layer and energy is dissipated in the form of heat. This form of energy dissipation allows the structural oscillations to attenuate much faster. The purpose behind this study is to predict damping effects by using two methods of passive viscoelastic constrained layer damping. First method is Euler-Bernoulli beam theory; it is commonly used for predicting the vibratory response of beams. Second method is Finite Element software packages provided in this research were obtained by using two-dimensional solid structural elements in ANSYS14 specifically eight nodded (SOLID183) and the output results from ANSYS 14 (SOLID183) its damped natural frequency values and mode shape for first five modes. This method of passive damping treatment is widely used for structural application in many industries like aerospace, automobile, etc. In this paper, take a steel cantilever sandwich beam with viscoelastic core type 3M-468 by using methods of passive viscoelastic constrained layer damping. Also can proved that, the percentage reduction of modal frequency between undamped and damped steel sandwich cantilever beam 8mm thickness for each mode is very high, this is due to the effect of viscoelastic layer on damped beams. Finally this types of damped sandwich steel cantilever beam with viscoelastic materials core type (3M468) is very appropriate to use in automotive industry and in many mechanical application, because has very high capability to reduce the modal vibration of structures.

Keywords: steel cantilever, sandwich beam, viscoelastic materials core type (3M468), ANSYS14, Euler-Bernoulli beam theory

Procedia PDF Downloads 295

Authors: Shian Guan, Marie Bourdin, Isabelle Trenque, Younes Messaddeq, Thierry Cardinal, Nicolas Penin, Issam Mjejri, Aline Rougier, Etienne Duguet, Stephane Mornet, Manuel Gaudon

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At the interface of the studies performed by 3 Ph.D. students: Shian Guan (2017-2020), Marie Bourdin (2016-2019) and Isabelle Trenque (2012-2015), a single synthesis route: polyol-mediated process, was used with success for the preparation of different inorganic oxides. Both of these inorganic oxides were elaborated for their potential application as smart optical compounds. This synthesis route has allowed us to develop nanoparticles of zinc oxide, vanadium oxide or tungsten oxide. This route is with easy implementation, inexpensive and with large-scale production potentialities and leads to materials of high purity. The obtaining by this route of nanometric particles, however perfectly crystalline, has notably led to the possibility of doping these matrix materials with high doping ion concentrations (high solubility limits). Thus, Al3+ or Ga3+ doped-ZnO powder, with high doping rate in comparison with the literature, exhibits remarkable infrared absorption properties thanks to their high free carrier density. Note also that due to the narrow particle size distribution of the as-prepared nanometric doped-ZnO powder, the original correlation between crystallite size and unit-cell parameters have been established. Also, depending on the annealing atmosphere use to treat vanadium precursors, VO2, V2O3 or V2O5 oxides with thermochromic or electrochromic properties can be obtained without any impurity, despite the versatility of the oxidation state of vanadium. This is of more particular interest on vanadium dioxide, a relatively difficult-to-prepare oxide, whose first-order metal-insulator phase transition is widely explored in the literature for its thermochromic behavior (in smart windows with optimal thermal insulation). Finally, the reducing nature of the polyol solvents ensures the production of oxygen-deficient tungsten oxide, thus conferring to the nano-powders exotic colorimetric properties, as well as optimized photochromic and electrochromic behaviors.

Keywords: inorganic oxides, electrochromic, photochromic, thermochromic

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Authors: Peter Kus, Anna Ostroverkh, Yurii Yakovlev, Yevheniia Lobko, Roman Fiala, Ivan Khalakhan, Vladimir Matolin

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Hydrogen economy is a concept of low-emission society which harvests most of its energy from renewable sources (e.g., wind and solar) and in case of overproduction, electrochemically turns the excess amount into hydrogen, which serves as an energy carrier. Proton exchange membrane water electrolyzers (PEMWE) are the backbone of this concept. By fast-response electricity to hydrogen conversion, the PEMWEs will not only stabilize the electrical grid but also provide high-purity hydrogen for variety of fuel cell powered devices, ranging from consumer electronics to vehicles. Wider commercialization of PEMWE technology is however hindered by high prices of noble metals which are necessary for catalyzing the redox reactions within the cell. Namely, platinum for hydrogen evolution reaction (HER), running on cathode, and iridium for oxygen evolution reaction (OER) on anode. Possible way of how to lower the loading of Pt and Ir is by using conductive high-surface nanostructures as catalyst supports in conjunction with thin-film catalyst deposition. The presented study discusses unconventional technique of membrane electron assembly (MEA) preparation. Noble metal catalysts (Pt and Ir) were magnetron sputtered in very low loadings onto the surface of porous sublayers (located on gas diffusion layer or directly on membrane), forming so to say localized three-phase boundary. Ultrasonically sprayed corrosion resistant TiC-based sublayer was used as a support material on anode, whereas magnetron sputtered nanostructured etched nitrogenated carbon (CNx) served the same role on cathode. By using this configuration, we were able to significantly decrease the amount of noble metals (to thickness of just tens of nanometers), while keeping the performance comparable to that of average state-of-the-art catalysts. Complex characterization of prepared supported catalysts includes in-cell performance and durability tests, electrochemical impedance spectroscopy (EIS) as well as scanning electron microscopy (SEM) imaging and X-ray photoelectron spectroscopy (XPS) analysis. Our research proves that magnetron sputtering is a suitable method for thin-film deposition of electrocatalysts. Tested set-up of thin-film supported anode and cathode catalysts with combined loading of just 120 ug.cm⁻² yields remarkable values of specific current. Described approach of thin-film low-loading catalyst deposition might be relevant when noble metal reduction is the topmost priority.

Keywords: hydrogen economy, low-loading catalyst, magnetron sputtering, proton exchange membrane water electrolyzer

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Authors: Laroussi Chaabane, Amel El Ghali, Emmanuel Beyou, Mohamed Hassen V. Baouab

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In this research, the functionalization of graphene oxide sheets by ethylenediamine (EDA) was accomplished and followed by the grafting of bis(2-pyridylmethyl) amino group (BPED) onto the activated graphene oxide sheets in the presence of chloroacetylchloride (CAC) and then combined with magnetic nanoparticles (Fe₃O₄NPs) to produce a magnetic graphene-based composite [(Go-EDA-CAC)@Fe₃O₄NPs-BPED]. The physicochemical properties of [(Go-EDA-CAC)@Fe₃O₄NPs-BPED] composites were investigated by Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA). Additionally, the catalysts can be easily recycled within ten seconds by using an external magnetic field. Moreover, [(Go-EDA-CAC)@Fe₃O₄NPs-BPED] was used for removing Cu(II) ions from aqueous solutions using a batch process. The effect of pH, contact time and temperature on the metal ions adsorption were investigated, however weakly dependent on ionic strength. The maximum adsorption capacity values of Cu(II) on the [(Go-EDA-CAC)@Fe₃O₄NPs-BPED] at the pH of 6 is 3.46 mmol.g⁻¹. To examine the underlying mechanism of the adsorption process, pseudo-first, pseudo-second-order, and intraparticle diffusion models were fitted to experimental kinetic data. Results showed that the pseudo-second-order equation was appropriate to describe the Cu (II) adsorption by [(Go-EDA-CAC)@Fe₃O₄NPs-BPED]. Adsorption data were further analyzed by the Langmuir, Freundlich, and Jossens adsorption approaches. Additionally, the adsorption properties of the [(Go-EDA-CAC)@Fe₃O₄NPs-BPED], their reusability (more than 6 cycles) and durability in the aqueous solutions open the path to removal of Cu(II) from water solution. Based on the results obtained, we report the activity of Cu(II) supported on [(Go-EDA-CAC)@Fe₃O₄NPs-BPED] as a catalyst for the cross-coupling of symmetric alkynes.

Keywords: graphene, magnetic nanoparticles, adsorption kinetics/isotherms, cross coupling

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Authors: Bhavya Tripathi, Bhupendra Kumar Sharma

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In blood, the concentration of red blood cell varies with the arterial diameter. In the case of narrow arteries, red blood cells concentrate around the center of the artery and there exists a cell-free plasma layer near the arterial wall due to Fahraeus-Lindqvist effect. Due to non- uniformity of the fluid in the narrow arteries, it is preferable to consider the two-phase model of the blood flow. In the present article, coupled nonlinear differential equations have been developed for momentum, energy and concentration of two phase model of the blood flow assuming the Newtonian fluid in both central core and cell free plasma layer and the exact solutions have been found for the problem. For having an adequate insight into the stenosed arterial two-phase blood flow, major components of the flow as flow resistance, total flow rate, and wall shear stress have been estimated for different values of magnetic and radiation parameter. Results show that the increase in the effects of magnetic field decreases the velocity of both cores as well as plasma regions. This result can be helpful to control the blood flow in narrow arteries during surgical process. Temperature of core as well plasma regions decrease as value of radiation parameter increases. The present result is implemented in the form of radiation therapy which is very helpful for cancer patients.

Keywords: two phase blood flow, radiation, magnetohydrodynamics (MHD), stenosis

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Authors: Nour S. Abdelrahman, Seunghyun Hong, Hassan A. Arafat, Daniel Choi, Faisal Al Marzooqi

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Abstract—The advancement of lithium extraction methods from water sources, particularly saltwater brine, is gaining prominence in the lithium recovery industry due to its cost-effectiveness. Traditional techniques like recrystallization, chemical precipitation, and solvent extraction for metal recovery from seawater or brine are energy-intensive and exhibit low efficiency. Moreover, the extensive use of organic solvents poses environmental concerns. As a result, there's a growing demand for environmentally friendly lithium recovery methods. Membrane-based separation technology has emerged as a promising alternative, offering high energy efficiency and ease of continuous operation. In our study, we explored the potential of lithium-selective sieve channels constructed from layers of 2D graphene oxide and MXene (transition metal carbides and nitrides), integrated with surface – SO₃₋ groups. The arrangement of these 2D sheets creates interplanar spacing ranging from 0.3 to 0.8 nm, which forms a barrier against multivalent ions while facilitating lithium-ion movement through nano capillaries. The introduction of the sulfonate group provides an effective pathway for Li⁺ ions, with a calculated binding energy of Li⁺ – SO³⁻ at – 0.77 eV, the lowest among monovalent species. These modified membranes demonstrated remarkably rapid transport of Li⁺ ions, efficiently distinguishing them from other monovalent and divalent species. This selectivity is achieved through a combination of size exclusion and varying binding affinities. The graphene oxide channels in these membranes showed exceptional inter-cation selectivity, with a Li⁺/Mg²⁺ selectivity ratio exceeding 104, surpassing commercial membranes. Additionally, these membranes achieved over 94% rejection of MgCl₂.

Keywords: ion permeation, lithium extraction, membrane-based separation, nanotechnology

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Authors: Thomas Jin-Chee Liu

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In this paper, the thermo-electro-structural coupled-field in a cracked metal plate is studied using the finite element analysis. From the computational results, the compressive stresses reveal near the crack tip. This conclusion agrees with the past reference. Furthermore, the compressive condition can retard and stop the crack growth during the Joule heating process.

Keywords: compressive stress, crack tip, Joule heating, finite element

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Authors: Evgeny A. Rybakov, Dmitry P. Starikov

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This article contains information about creating special unit for scanning 3D objects different nature, different materials, for example plastic, plaster, cardboard, wood, metal and etc. The main part of the unit is infrared transducer, which is sends the wave to the object and receive back wave for calculating distance. After that, microcontroller send to PC data, and computer program create model for printing from the plastic, gypsum, brass, etc.

Keywords: clutch, infrared, microcontroller, plastic, shaft, stage

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Authors: Preethi Kumari P., Shetty Prakasha, Rao Suma A.

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Mild steel has been widely employed as construction materials for pipe work in the oil and gas production such as down hole tubular, flow lines and transmission pipelines, in chemical and allied industries for handling acids, alkalis and salt solutions due to its excellent mechanical property and low cost. Acid solutions are widely used for removal of undesirable scale and rust in many industrial processes. Among the commercially available acids hydrochloric acid is widely used for pickling, cleaning, de-scaling and acidization of oil process. Mild steel exhibits poor corrosion resistance in presence of hydrochloric acid. The high reactivity of mild steel in presence of hydrochloric acid is due to the soluble nature of ferrous chloride formed and the cementite phase (Fe3C) normally present in the steel is also readily soluble in hydrochloric acid. Pitting attack is also reported to be a major form of corrosion in mild steel in the presence of high concentrations of acids and thereby causing the complete destruction of metal. Hydrogen from acid reacts with the metal surface and makes it brittle and causes cracks, which leads to pitting type of corrosion. The use of chemical inhibitor to minimize the rate of corrosion has been considered to be the first line of defense against corrosion. In spite of long history of corrosion inhibition, a highly efficient and durable inhibitor that can completely protect mild steel in aggressive environment is yet to be realized. It is clear from the literature review that there is ample scope for the development of new organic inhibitors, which can be conveniently synthesized from relatively cheap raw materials and provide good inhibition efficiency with least risk of environmental pollution. The aim of the present work is to evaluate the electrochemical parameters for the corrosion inhibition behavior of an aromatic hydrazide derivative, 4-hydroxy- N '-[(E)-1H-indole-2-ylmethylidene)] benzohydrazide (HIBH) on mild steel in 2M hydrochloric acid using Tafel polarization and electrochemical impedance spectroscopy (EIS) techniques at 30-60 °C. The results showed that inhibition efficiency increased with increase in inhibitor concentration and decreased marginally with increase in temperature. HIBH showed a maximum inhibition efficiency of 95 % at 8×10-4 M concentration at 30 °C. Polarization curves showed that HIBH act as a mixed-type inhibitor. The adsorption of HIBH on mild steel surface obeys the Langmuir adsorption isotherm. The adsorption process of HIBH at the mild steel/hydrochloric acid solution interface followed mixed adsorption with predominantly physisorption at lower temperature and chemisorption at higher temperature. Thermodynamic parameters for the adsorption process and kinetic parameters for the metal dissolution reaction were determined.

Keywords: electrochemical parameters, EIS, mild steel, tafel polarization

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Authors: J. Švarc-Gajić, A. Cvetanović

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Apigenin is a flavone synthetized by many plants and quite abundant in chamomile (Matricaria recutita) in its free form and in the form of its glucoside and different acylated forms. Many beneficial health effects have been attributed to apigenin, such as chemo-preventive, anxiolytic, anti-inflammatory, antioxidant and antispasmodic. It is reported that free apigenin is much more bioactive in comparison to its bound forms. Subcritical water offers numerous advantages in comparison to conventional extraction techniques, such as good selectivity, low price and safety. Superheated water exhibits high hydrolytical potential which must be carefully balanced when using this solvent for the extraction of bioactive molecules. Moderate hydrolytical potential can be exploited to liberate apigenin from its bound forms, thus increasing biological potential of obtained extracts. The polarity of pressurized water and its hydrolytical potential are highly dependent on the temperature. In this research chamomile ligulate flowers were extracted by pressurized hot water in home-made subcritical water extractor in conditions of convective mass transfer. The influence of the extraction temperature was investigated at 30 bars. Extraction yields of total phenols, total flavonoids and apigenin depending on the operational temperature were calculated based on spectrometric assays. Optimal extraction temperature for maximum yields of total phenols and flavonoids showed to be 160°C, whereas apigenin yield was the highest at 120°C.

Keywords: superheated water, temperature, chamomile, apigenin

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Authors: Fiona S. Motswaiso, Kengo Nakamura, Takeshi Komai

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Heavy metals may occur naturally in rocks and soils, but elevated quantities of them are being gradually released into the environment by anthropogenic activities such as mining. In order to address issues of heavy metal water and soil pollution, a distinction needs to be made between natural and anthropogenic anomalies. The current study aims at characterizing the spatial distribution of trace elements and evaluate site-specific geochemical background concentrations of trace elements in the mine soils examined, and also to discriminate between lithogenic and anthropogenic sources of enrichment around a copper-nickel mining town in Selibe-Phikwe, Botswana. A total of 20 Soil samples, 11 river sediment, and 9 river water samples were collected from an area of 625m² within the precincts of the mine and the smelter. The concentrations of metals (Cu, Ni, Pb, Zn, Cr, Ni, Mn, As, Pb, and Co) were determined by using an ICP-MS after digestion with aqua regia. Major elements were also determined using ED-XRF. Water pH and EC were measured on site and recorded while soil pH and EC were also determined in the laboratory after performing water elution tests. The highest Cu and Ni concentrations in soil are 593mg/kg and 453mg/kg respectively, which is 3 times higher than the crustal composition values and 2 times higher than the South African minimum allowable levels of heavy metals in soils. The level of copper contamination was higher than that of nickel and other contaminants. Water pH levels ranged from basic (9) to very acidic (3) in areas closer to the mine/smelter. There is high variation in heavy metal concentration, eg. Cu suggesting that some sites depict regional natural background concentrations while other depict anthropogenic sources.

Keywords: contamination, geochemical baseline, heavy metals, soils

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Authors: Burcu Ileri, Deniz Sanliyuksel Yucel, Onder Ayyildiz

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The oxidation of pyrite in water results in the formation of acid mine drainage, which typically forms extremely acid mine lake (AML) in the depression areas of abandoned Etili open-pit coal mine site, Northwest Turkey. Nine acid mine lakes of various sizes have been located in the Etili coal mine site. Hayirtepe AML is one of the oldest lake having a mean pH value of 2.9 and conductivity of 4550 μS/cm, and containing elevated concentrations of Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, and Zn. The water quality of the lake has been deteriorated due to its high chemical composition, in particular, increasing heavy metal pollution. In this study, fly ash (FA), a coal combustion by-product from fluidized bed thermal power plant in the northwestern part of Turkey, was used as an adsorbent for the treatment of Hayirtepe AML. The FA is a relatively abundant and cost effective material, but its use in adsorption processes usually require excessive adsorbent doses. To increase adsorption efficiency and lower the adsorbent dose, we modified the FA by means of ultrasonic treatment (20 kHz and 40 kHz). The images of scanning electron microscopy (SEM) have demonstrated that ultrasonic treatment not only decreased the size of ash particles but also created pits and cracks on their surfaces which in turn led to a significant increase in the BET surface area. Both FA and modified fly ash were later tested for the removal of heavy metals from the AML. The effect of various operating parameters such as ultrasonic power, pH, ash dose, and adsorption contact time were examined to obtain the optimum conditions for the treatment process. The results have demonstrated that removal of heavy metals by ultrasound-modified fly ash requires much shorter treatment times and lower adsorbent doses than those attained by the unmodified fly ash. This research was financially supported by the Scientific and Technological Research Council of Turkey (TUBITAK), (Project no: 116Y510).

Keywords: acid mine lake, heavy metal, modified fly ash, ultrasonic treatment

Procedia PDF Downloads 184

Authors: M. Tammaro, S. Manzo, J. Rimauro, A. Salluzzo, S. Schiavo

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The solar photovoltaic (PV) modules are considered to have a negligible environmental impact compared to the fossil energy. Therefore also the waste management and the corresponding potential environmental hazard needs to be considered. The case of the photovoltaic panel is unique because the time lag from the manufacturing to the decommissioning as waste usually takes 25-30 years. Then the environmental hazard associated with end life of PV panels has been largely related to their metal contents. The principal concern regards the presence of heavy metals as Cd in thin film (TF) modules or Pb and Cr in crystalline silicon (c-Si) panels. At the end of life of PV panels, these dangerous substances could be released in the environment, if special requirements for their disposal are not adopted. Nevertheless, in literature, only a few experimental study about metal emissions from silicon crystalline/thin film panels and the corresponding environmental effect are present. As part of a study funded by the Italian national consortium for the waste collection and recycling (COBAT), the present work was aimed to analyze experimentally the potential release into the environment of hazardous elements, particularly metals, from PV waste. In this paper, for the first time, eighteen releasable metals a large number of photovoltaic panels, by c-Si and TF, manufactured in the last 30 years, together with the environmental effects by a battery of ecotoxicological tests, were investigated. Leaching tests are conducted on the crushed samples of PV module. The test is conducted according to Italian and European Standard procedure for hazard assessment of the granular waste and of the sludge. The sample material is shaken for 24 hours in HDPE bottles with an overhead mixer Rotax 6.8 VELP at indoor temperature and using pure water (18 MΩ resistivity) as leaching solution. The liquid-to-solid ratio was 10 (L/S=10, i.e. 10 liters of water per kg of solid). The ecotoxicological tests were performed in the subsequent 24 hours. A battery of toxicity test with bacteria (Vibrio fisheri), algae (Pseudochirneriella subcapitata) and crustacea (Daphnia magna) was carried out on PV panel leachates obtained as previously described and immediately stored in dark and at 4°C until testing (in the next 24 hours). For understand the actual pollution load, a comparison with the current European and Italian benchmark limits was performed. The trend of leachable metal amount from panels in relation to manufacturing years was then highlighted in order to assess the environmental sustainability of PV technology over time. The experimental results were very heterogeneous and show that the photovoltaic panels could represent an environmental hazard. The experimental results showed that the amounts of some hazardous metals (Pb, Cr, Cd, Ni), for c-Si and TF, exceed the law limits and they are a clear indication of the potential environmental risk of photovoltaic panels "as a waste" without a proper management.

Keywords: photovoltaic panel, environment, ecotoxicity, metals emission

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Authors: Bedarnia Ishak

Abstract:

In the recent years, the dry reforming of methane has received considerable attention from an environmental view point because it consumes and eliminates two gases (CH4 and CO2) responsible for global warming by greenhouse effect. Many catalysts containing noble metal (Rh, Ru, Pd, Pt and Ir) or transition metal (Ni, Co and Fe) have been reported to be active in this reaction. Compared to noble metals, Ni-materials are cheap but very easily deactivated by coking. Ni-based mixed oxides structurally well-defined like perovskites and spinels are being studied because they possibly make solid solutions and allow to vary the composition and thus the performances properties. In this work, nano-sized nickel ferrite oxides are synthesized using three different methods: Co-precipitation (CP), hydrothermal (HT) and sol gel (SG) methods and characterized by XRD, Raman, XPS, BET, TPR, SEM-EDX and TEM-EDX. XRD patterns of all synthesized oxides showed the presence of NiFe2O4 spinel, confirmed by Raman spectroscopy. Hematite was present only in CP sample. Depending on the synthesis method, the surface area, particle size, as well as the surface Ni/Fe atomic ratio (XPS) and the behavior upon reduction varied. The materials were tested in methane dry reforming with CO2 at 1 atm and 650-800 °C. The catalytic activity of the spinel samples was not very high (XCH4 = 5-20 mol% and XCO2 = 25-40 mol %) when no pre-reduction step was carried out. A significant contribution of RWGS explained the low values of H2/CO ratio obtained. The reoxidation step of the catalyst carried out after reaction showed little amounts of coke deposition. The reducing pretreatment was particularly efficient in the case of SG (XCH4 = 80 mol% and XCO2 = 92 mol%, at 800 °C), with H2/CO > 1. In conclusion, the influence of preparation was strong for most samples and the catalytic behavior could be interpreted by considering the distribution of cations among octahedral (Oh) and tetrahedral (Td) sites as in (Ni2+1-xFe3+x) Td (Ni2+xFe3+2-x) OhO2-4 influenced the reducibility of materials and thus their catalytic performance.

Keywords: NiFe2O4, dry reforming of methane, spinel oxide, oxide zenc

Procedia PDF Downloads 269

Authors: Megha Agarwal

Abstract:

The research paper is an effort to compare the earnings based and cash flow based methods of valuation of an enterprise. The theoretically equivalent methods based on either earnings such as Residual Earnings Model (REM), Abnormal Earnings Growth Model (AEGM), Residual Operating Income Method (ReOIM), Abnormal Operating Income Growth Model (AOIGM) and its extensions multipliers such as price/earnings ratio, price/book value ratio; or cash flow based models such as Dividend Valuation Method (DVM) and Free Cash Flow Method (FCFM) all provide different estimates of valuation of the Indian giant corporate Reliance India Limited (RIL). An ex-post analysis of published accounting and financial data for four financial years from 2008-09 to 2011-12 has been conducted. A comparison of these valuation estimates with the actual market capitalization of the company shows that the complex accounting based model AOIGM provides closest forecasts. These different estimates may be derived due to inconsistencies in discount rate, growth rates and the other forecasted variables. Although inputs for earnings based models may be available to the investor and analysts through published statements, precise estimation of free cash flows may be better undertaken by the internal management. The estimation of value from more stable parameters as residual operating income and RNOA could be considered superior to the valuations from more volatile return on equity.

Keywords: earnings, cash flows, valuation, Residual Earnings Model (REM)

Procedia PDF Downloads 357

Authors: S. Wakim, M. Nemer, B. Zeghondy, B. Ghannam, C. Bouallou

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Designing the optimal heat exchanger is still an essential objective to be achieved. Parametrical optimization involves the evaluation of the heat exchanger dimensions to find those that best satisfy certain objectives. This method contributes to an enhanced design rather than an optimized one. On the contrary, topology optimization finds the optimal structure that satisfies the design objectives. The huge development in metal additive manufacturing allowed topology optimization to find its way into engineering applications especially in the aerospace field to optimize metal structures. Using topology optimization in 3d heat and mass transfer problems requires huge computational time, therefore coupling it with CFD simulations can reduce this it. However, existed CFD models cannot be coupled with topology optimization. The CFD model must allow creating a uniform mesh despite the initial geometry complexity and also to swap the cells from fluid to solid and vice versa. In this paper, a porous media approach compatible with topology optimization criteria is developed. It consists of modeling the fluid region of the heat exchanger as porous media having high porosity and similarly the solid region is modeled as porous media having low porosity. The switching from fluid to solid cells required by topology optimization is simply done by changing each cell porosity using a user defined function. This model is tested on a plate and fin heat exchanger and validated by comparing its results to experimental data and simulations results. Furthermore, this model is used to perform a material reallocation based on local criteria to optimize a plate and fin heat exchanger under a constant heat duty constraint. The optimized fin uses 20% fewer materials than the first while the pressure drop is reduced by about 13%.

Keywords: computational methods, finite element method, heat exchanger, porous media, topology optimization

Procedia PDF Downloads 142

Authors: Bouhenni Mohamed Saif El Islam

Abstract:

In the recent years, the dry reforming of methane has received considerable attention from an environmental view point because it consumes and eliminates two gases (CH4 and CO2) responsible for global warming by greenhouse effect. Many catalysts containing noble metal (Rh, Ru, Pd, Pt and Ir) or transition metal (Ni, Co and Fe) have been reported to be active in this reaction. Compared to noble metals, Ni-materials are cheap but very easily deactivated by coking. Ni-based mixed oxides structurally well-defined like perovskites and spinels are being studied because they possibly make solid solutions and allow to vary the composition and thus the performances properties. In this work, nano-sized nickel ferrite oxides are synthesized using three different methods: Co-precipitation (CP), hydrothermal (HT) and sol gel (SG) methods and characterized by XRD, Raman, XPS, BET, TPR, SEM-EDX and TEM-EDX. XRD patterns of all synthesized oxides showed the presence of NiFe2O4 spinel, confirmed by Raman spectroscopy. Hematite was present only in CP sample. Depending on the synthesis method, the surface area, particle size, as well as the surface Ni/Fe atomic ratio (XPS) and the behavior upon reduction varied. The materials were tested in methane dry reforming with CO2 at 1 atm and 650-800 °C. The catalytic activity of the spinel samples was not very high (XCH4 = 5-20 mol% and XCO2 = 25-40 mol %) when no pre-reduction step was carried out. A significant contribution of RWGS explained the low values of H2/CO ratio obtained. The reoxidation step of the catalyst carried out after reaction showed little amounts of coke deposition. The reducing pretreatment was particularly efficient in the case of SG (XCH4 = 80 mol% and XCO2 = 92 mol%, at 800 °C), with H2/CO > 1. In conclusion, the influence of preparation was strong for most samples and the catalytic behavior could be interpreted by considering the distribution of cations among octahedral (Oh) and tetrahedral (Td) sites as in (Ni2+1-xFe3+x)Td (Ni2+xFe3+2-x)OhO2-4 influenced the reducibility of materials and thus their catalytic performance.

Keywords: NiFe2O4, dry reforming of methane, spinel oxide, XCO2

Procedia PDF Downloads 370

Authors: Rajesh Agarwal

Abstract:

Carrier mobility at the organic/insulator interface is essential to the performance of organic thin film transistors (OTFT). The present work describes estimation of field dependent mobility (FDM) parameters and the threshold voltage of an OTFT using a simple, easy to fabricate two terminal asymmetric capacitive test structure using admittance measurements. Conventionally, transfer characteristics are used to estimate the threshold voltage in an OTFT with field independent mobility (FIDM). Yet, this technique breaks down to give accurate results for devices with high contact resistance and having field dependent mobility. In this work, a new technique is presented for characterization of long channel organic capacitor (LCOC). The proposed technique helps in the accurate estimation of mobility enhancement factor (γ), the threshold voltage (V_th) and band mobility (µ₀) using capacitance-voltage (C-V) measurement in OTFT. This technique also helps to get rid of making short channel OTFT or metal-insulator-metal (MIM) structures for making C-V measurements. To understand the behavior of devices and ease of analysis, transmission line compact model is developed. The 2-D numerical simulation was carried out to illustrate the correctness of the model. Results show that proposed technique estimates device parameters accurately even in the presence of contact resistance and field dependent mobility. Pentacene/Poly (4-vinyl phenol) based top contact bottom-gate OTFT’s are fabricated to illustrate the operation and advantages of the proposed technique. Small signal of frequency varying from 1 kHz to 5 kHz and gate potential ranging from +40 V to -40 V have been applied to the devices for measurement.

Keywords: capacitance, mobility, organic, thin film transistor

Procedia PDF Downloads 151

Authors: Nader Nciri, Suil Song, Namho Kim, Namjun Cho

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Properties and compositions of bitumen and bitumen-derived liquids have significant influences on the selection of recovery, upgrading and refining processes. Optimal process conditions can often be directly related to these properties. The end uses of bitumen and bitumen products are thus related to their compositions. Because it is not possible to conduct a complete analysis of the molecular structure of bitumen, characterization must be made in other terms. The present paper focuses on physico-chemical analysis of two different types of bitumens. These bitumen samples were chosen based on: the original crude oil (sand oil and crude petroleum), and mode of process. The aim of this study is to determine both the manufacturing effect on chemical species and the chemical organization as a function of the type of bitumen sample. In order to obtain information on bitumen chemistry, elemental analysis (C, H, N, S, and O), heavy metal (Ni, V) concentrations, IATROSCAN chromatography (thin layer chromatography-flame ionization detection), FTIR spectroscopy, and 1H NMR spectroscopy have all been used. The characterization includes information about the major compound types (saturates, aromatics, resins and asphaltenes) which can be compared with similar data for other bitumens, more importantly, can be correlated with data from petroleum samples for which refining characteristics are known. Examination of Asphalt Ridge froth bitumen showed that it differed significantly from representative petroleum pitches, principally in their nonhydrocarbon content, heavy metal content and aromatic compounds. When possible, properties and composition were related to recovery and refining processes. This information is important because of the effects that composition has on recovery and processing reactions.

Keywords: froth bitumen, oil sand, asphalt ridge, petroleum pitch, thin layer chromatography-flame ionization detection, infrared spectroscopy, 1H nuclear magnetic resonance spectroscopy

Procedia PDF Downloads 410

Authors: Natália Maria Rego

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ALeibnizn-algebraGis aK-vector space endowed whit a n-linearbracket operation [-,…-] : GG … G→ Gsatisfying the fundamental identity, which can be expressed saying that the right multiplication map Ry2, …, ᵧₙ: Gn→ G, Rᵧ₂, …, ᵧₙn(ˣ¹, …, ₓₙ) = [[ˣ¹, …, ₓₙ], ᵧ₂, …, ᵧₙ], is a derivation. This structure, together with its skew-symmetric version, named as Lie n-algebra or Filippov algebra, arose in the setting of Nambumechanics, an n-ary generalization of the Hamiltonian mechanics. Thefirst goal of this work is to provide a characterization of various classes of central extensions of Leibniz n-algebras in terms of homological properties. Namely, Commutator extension, Quasi-commutator extension, Stem extension, and Stem cover. These kind of central extensions are characterized by means of the character of the map *(E): nHL1(G) → M provided by the five-term exact sequence in homology with trivial coefficients of Leibniz n-algebras associated to an extension E : 0 → M → K → G → 0. For a free presentation 0 →R→ F →G→ 0of a Leibniz n-algebra G,the term M(G) = (R[F,…n.., F])/[R, F,..n-1..,F] is called the Schur multiplier of G, which is a Baer invariant, i.e., it does not depend on the chosen free presentation, and it is isomorphic to the first Leibniz n-algebras homology with trivial coefficients of G. A central extension of Leibniz n-algebras is a short exact sequenceE : 0 →M→K→G→ 0such that [M, K,.. ⁿ⁻¹.., K]=0. It is said to be a stem extension if M⊆[G, .. n.., G]. Additionally, if the induced map M(K) → M(G) is the zero map, then the stem extension Eis said to be a stem cover. The second aim of this work is to analyze the interplay between stem covers of Leibniz n-algebras and the Schur multiplier. Concretely, in the case of finite-dimensional Leibniz n-algebras, we show the existence of coverings, and we prove that all stem covers with finite-dimensional Schur multiplier are isoclinic. Additionally, we characterize stem covers of perfect Leibniz n-algebras.

Keywords: leibniz n-algebras, central extensions, Schur multiplier, stem cover

Procedia PDF Downloads 148

Authors: Hafida Ferfera-Harrar, Nacera Aiouaz, Nassima Dairi

Abstract:

Super absorbents polymers received much attention and are used in many fields because of their superior characters to traditional absorbents, e.g., sponge and cotton. So, it is very important but challenging to prepare highly and fast-swelling super absorbents. A reliable, efficient and low-cost technique for removing heavy metal ions from waste water is the adsorption using bio-adsorbents obtained from biological materials, such as polysaccharides-based hydrogels super absorbents. In this study, novel multi-functional super absorbent composites type semi-interpenetrating polymer networks (Semi-IPNs) were prepared via graft polymerization of acrylamide onto chitosan backbone in presence of gelatin, CTS-g-PAAm/Ge, using potassium persulfate and N,N’ -methylenebisacrylamide as initiator and cross linker, respectively. These hydrogels were also partially hydrolyzed to achieve superabsorbents with ampholytic properties and uppermost swelling capacity. The formation of the grafted network was evidenced by Fourier Transform Infrared Spectroscopy (ATR-FTIR) and thermo gravimetric Analysis (TGA). The porous structures were observed by Scanning Electron Microscope (SEM). From TGA analysis, it was concluded that the incorporation of the Ge in the CTS-g-PAAm network has marginally affected its thermal stability. The effect of gelatin content on the swelling capacities of these super absorbent composites was examined in various media (distilled water, saline and pH-solutions).The water absorbency was enhanced by adding Ge in the network, where the optimum value was reached at 2 wt. % of Ge. Their hydrolysis has not only greatly optimized their absorption capacity but also improved the swelling kinetic. These materials have also showed reswelling ability. We believe that these super-absorbing materials would be very effective for the adsorption of harmful metal ions from waste water.

Keywords: chitosan, gelatin, superabsorbent, water absorbency

Procedia PDF Downloads 441

Authors: Pejman Salimi, Sebastiano Tieuli, Somayeh Taghavi, Michela Signoretto, Remo Proietti Zaccaria

Abstract:

Increasing the growth of industrial waste due to the large quantities of production leads to numerous environmental and economic challenges, such as climate change, soil and water contamination, human disease, etc. Energy recovery of waste can be applied to produce heat or electricity. This strategy allows for the reduction of energy produced using coal or other fuels and directly reduces greenhouse gas emissions. Among different factories, leather manufacturing plays a very important role in the whole world from the socio-economic point of view. The leather industry plays a very important role in our society from a socio-economic point of view. Even though the leather industry uses a by-product from the meat industry as raw material, it is considered as an activity demanding integrated prevention and control of pollution. Along the entire process from raw skins/hides to finished leather, a huge amount of solid and water waste is generated. Solid wastes include fleshings, raw trimmings, shavings, buffing dust, etc. One of the most abundant solid wastes generated throughout leather tanning is shaving waste. Leather shaving is a mechanical process that aims at reducing the tanned skin to a specific thickness before tanning and finishing. This product consists mainly of collagen and tanning agent. At present, most of the world's leather processing is chrome-tanned based. Consequently, large amounts of chromium-containing shaving wastes need to be treated. The major concern about the management of this kind of solid waste is ascribed to chrome content, which makes the conventional disposal methods, such as landfilling and incineration, not practicable. Therefore, many efforts have been developed in recent decades to promote eco-friendly/alternative leather production and more effective waste management. Herein, shaving waste resulting from metal-free tanning technology is proposed as low-cost precursors for the preparation of carbon material as anodes for lithium-ion batteries (LIBs). In line with the philosophy of a reduced environmental impact, for preparing fully sustainable and environmentally friendly LIBs anodes, deionized water and carboxymethyl cellulose (CMC) have been used as alternatives to toxic/teratogen N-methyl-2- pyrrolidone (NMP) and to biologically hazardous Polyvinylidene fluoride (PVdF), respectively. Furthermore, going towards the reduced cost, we employed water solvent and fluoride-free bio-derived CMC binder (as an alternative to NMP and PVdF, respectively) together with LiFePO₄ (LFP) when a full cell was considered. These actions make closer to the 2030 goal of having green LIBs at 100 $ kW h⁻¹. Besides, the preparation of the water-based electrodes does not need a controlled environment and due to the higher vapour pressure of water in comparison with NMP, the water-based electrode drying is much faster. This aspect determines an important consequence, namely a reduced energy consumption for the electrode preparation. The electrode derived from leather waste demonstrated a discharge capacity of 735 mAh g⁻¹ after 1000 charge and discharge cycles at 0.5 A g⁻¹. This promising performance is ascribed to the synergistic effect of defects, interlayer spacing, heteroatoms-doped (N, O, and S), high specific surface area, and hierarchical micro/mesopore structure of the biochar. Interestingly, these features of activated biochars derived from the leather industry open the way for possible applications in other EESDs as well.

Keywords: biowaste, lithium-ion batteries, physical activation, waste management, leather industry

Procedia PDF Downloads 157

Authors: Sultan Ghaleb Aldaihani

Abstract:

- The environment in which educational leadership takes place is becoming increasingly complex due to factors like globalization and rapid technological change. - This is creating a "leadership gap" where the complexity of the environment outpaces the ability of leaders to effectively respond. - Educational leadership involves guiding teachers and the broader school system towards improved student learning and achievement. 2. Implications of Artificial Intelligence (AI) in Educational Leadership: - AI has great potential to enhance education, such as through intelligent tutoring systems and automating routine tasks to free up teachers. - AI can also have significant implications for educational leadership by providing better information and data-driven decision-making capabilities. - Computer-adaptive testing can provide detailed, individualized data on student learning that leaders can use for instructional decisions and accountability. 3. Enhancing Decision-Making Processes: - Statistical models and data mining techniques can help identify at-risk students earlier, allowing for targeted interventions. - Probability-based models can diagnose students likely to drop out, enabling proactive support. - These data-driven approaches can make resource allocation and decision-making more effective. 4. Improving Efficiency and Productivity: - AI systems can automate tasks and change processes to improve the efficiency of educational leadership and administration. - Integrating AI can free up leaders to focus more on their role's human, interactive elements.

Keywords: Education, Leadership, Technology, Artificial Intelligence

Procedia PDF Downloads 13