Search results for: thermal efficiency.

Authors: Mrinmoy Dhara, Vivek K. Sengar, Shovan L. Chattoraj, Soumiya Bhattacharjee

Abstract:

Remote sensing techniques have emerged as an asset for various geological studies. Satellite images obtained by different sensors contain plenty of information related to the terrain. Digital image processing further helps in customized ways for the prospecting of minerals. In this study, an attempt has been made to map the hydrothermally altered zones using multispectral and hyperspectral datasets of South East Rajasthan. Advanced Space-borne Thermal Emission and Reflection Radiometer (ASTER) and Hyperion (Level1R) dataset have been processed to generate different Band Ratio Composites (BRCs). For this study, ASTER derived BRCs were generated to delineate the alteration zones, gossans, abundant clays and host rocks. ASTER and Hyperion images were further processed to extract mineral end members and classified mineral maps have been produced using Spectral Angle Mapper (SAM) method. Results were validated with the geological map of the area which shows positive agreement with the image processing outputs. Thus, this study concludes that the band ratios and image processing in combination play significant role in demarcation of alteration zones which may provide pathfinders for mineral prospecting studies.

Keywords: ASTER, hyperion, band ratios, alteration zones, SAM

Procedia PDF Downloads 270

Authors: Mozhgan Hosseinnezhad, Kamaladin Gharanjig, Mehdi Ghahari

Abstract:

Dye-sensitized solar cells are sustainable tool for generating electrical energy using sunlight. To develop this technology, obstacles such as cost and the use of expensive compounds must be overcome. Herein, we employed a MoS₂/graphene composite instead of platinum in the DSSCs. Platinum is an efficient and conventional counter electrode in the preparation of DSSCs, for this purpose, the effect of the presence of platinum electrode was also studied under similar conditions. The prepared nanocomposite product was checked by analysis methods to confirm the correctness of the construction and the desired structure. Finally, the DSSCs were fabricated using MoS₂/graphene composite, and to compare the results, the DSSCs were also prepared using platinum. The results showed that the prepared composite has a similar performance compared to platinum and can replace it.

Keywords: efficiency, dye-sensitized solar cell, nano-composite MoS₂, platinum free

Procedia PDF Downloads 53

Authors: Simran Baweja, Bhavika Kalal, Surajit Maity

Abstract:

Photoinduced tautomerization reactions have been the centre of attention among the scientific community over the past several decades because of their significance in various biological systems. 7-azaindole (7AI) is considered a model system for DNA base pairing and to understand the role of such tautomerization reactions in mutations. To the best of our knowledge, extensive studies have been carried out on 7-azaindole and its solvent clusters exhibiting proton/ hydrogen transfer in both solution as well as gas phases. Derivatives of the above molecule, like 2,7- and 2,6-diazaindoles are proposed to have even better photophysical properties due to the presence of -aza group on the 2nd position. However, there are studies in the solution phase that suggest the relevance of these molecules, but there are no experimental studies reported in the gas phase yet. In our current investigation, we present the first gas phase spectroscopic data of 2,7-diazaindole (2,7-DAI) and its solvent cluster (2,7-DAI-H2O). In this, we have employed state-of-the-art laser spectroscopic methods such as fluorescence excitation (LIF), dispersed fluorescence (DF), resonant two-photon ionization-time of flight mass spectrometry (2C-R2PI), photoionization efficiency spectroscopy (PIE), IR-UV double resonance spectroscopy, i.e., fluorescence-dip infrared spectroscopy (FDIR) and resonant ion-dip infrared spectroscopy (IDIR) to understand the electronic structure of the molecule. The origin band corresponding to the S1 ← S0 transition of the bare 2,7-DAI is found to be positioned at 33910 cm-1, whereas the origin band corresponding to S1 ← S0 transition of the 2,7-DAI-H2O is positioned at 33074 cm-1. The red-shifted transition in the case of solvent cluster suggests the enhanced feasibility of excited state hydrogen/ proton transfer. The ionization potential for the 2,7-DAI molecule is found to be 8.92 eV which is significantly higher than the previously reported 7AI (8.11 eV) molecule, making it a comparatively complex molecule to study. The ionization potential is reduced by 0.14 eV in the case of 2,7-DAI-H2O (8.78 eV) cluster compared to that of 2,7-DAI. Moreover, on comparison with the available literature values of 7AI, we found the origin band of 2,7-DAI and 2,7-DAI-H2O to be red-shifted by -729 and -280 cm-1 respectively. The ground and excited state N-H stretching frequencies of the 27DAI molecule were determined using fluorescence-dip infrared spectra (FDIR) and resonant ion dip infrared spectroscopy (IDIR), obtained at 3523 and 3467 cm-1, respectively. The lower value of vNH in the electronically excited state of 27DAI implies the higher acidity of the group compared to the ground state. Moreover, we have done extensive computational analysis, which suggests that the energy barrier in the excited state reduces significantly as we increase the number of catalytic solvent molecules (S= H2O, NH3) as well as the polarity of solvent molecules. We found that the ammonia molecule is a better candidate for hydrogen transfer compared to water because of its higher gas-phase basicity. Further studies are underway to understand the excited state dynamics and photochemistry of such N-rich chromophores.

Keywords: excited state hydrogen transfer, supersonic expansion, gas phase spectroscopy, IR-UV double resonance spectroscopy, laser induced fluorescence, photoionization efficiency spectroscopy

Procedia PDF Downloads 61

Authors: Guanlin Wu, Jiajia Yao, Fang Liu, Junshuai Xue, Jincheng Zhang, Yue Hao

Abstract:

Owing to the excellent thermal conductivity and ultra-wide bandgap, Aluminum nitride (AlN)/Gallium nitride (GaN) is a highly promising material to achieve high breakdown voltage and output power devices among III-nitrides. In this study, we explore the growth and characterization of polarization-induced AlN/GaN heterostructures using plasma-assisted molecular beam epitaxy (PA-MBE) on AlN-on-sapphire templates. To improve the crystal quality and demonstrate the effectiveness of the PA-MBE approach, a thick AlN buffer of 180 nm was first grown on the AlN-on sapphire template. This buffer acts as a back-barrier to enhance the breakdown characteristic and isolate leakage paths that exist in the interface between the AlN epilayer and the AlN template. A root-mean-square roughness of 0.2 nm over a scanned area of 2×2 µm2 was measured by atomic force microscopy (AFM), and the full-width at half-maximum of (002) and (102) planes on the X-ray rocking curve was 101 and 206 arcsec, respectively, using by high-resolution X-ray diffraction (HR-XRD). The electron mobility of 443 cm2/Vs with a carrier concentration of 2.50×1013 cm-2 at room temperature was achieved in the AlN/GaN heterostructures by using a polarization-induced GaN channel. The low depletion capacitance of 15 pF is resolved by the capacitance-voltage. These results indicate that the polarization-induced AlN/GaN heterostructures have great potential for next-generation high-temperature, high-frequency, and high-power electronics.

Keywords: AlN, GaN, MBE, heterostructures

Procedia PDF Downloads 70

Authors: Georgi Y. Georgiev, Matthew Brouillet

Abstract:

This research applies the power of agent-based modeling to a pivotal question at the intersection of biology, computer science, physics, and complex systems theory about the self-organization processes in open, complex, non-equilibrium thermodynamic systems. Central to this investigation is the principle of Maximum Entropy Production (MEP). This principle suggests that such systems evolve toward states that optimize entropy production, leading to the formation of structured environments. It is hypothesized that guided by the least action principle, open thermodynamic systems identify and follow the shortest paths to transmit energy and matter, resulting in maximal entropy production, internal structure formation, and a decrease in internal entropy. Concurrently, it is predicted that there will be an increase in system information as more information is required to describe the developing structure. To test this, an agent-based model is developed simulating an ant colony's formation of a path between a food source and its nest. Utilizing the Netlogo software for modeling and Python for data analysis and visualization, self-organization is quantified by calculating the decrease in system entropy based on the potential states and distribution of the ants within the simulated environment. External entropy production is also evaluated for information increase and efficiency improvements in the system's action. Simulations demonstrated that the system begins at maximal entropy, which decreases as the ants form paths over time. A range of system behaviors contingent upon the number of ants are observed. Notably, no path formation occurred with fewer than five ants, whereas clear paths were established by 200 ants, and saturation of path formation and entropy state was reached at populations exceeding 1000 ants. This analytical approach identified the inflection point marking the transition from disorder to order and computed the slope at this point. Combined with extrapolation to the final path entropy, these parameters yield important insights into the eventual entropy state of the system and the timeframe for its establishment, enabling the estimation of the self-organization rate. This study provides a novel perspective on the exploration of self-organization in thermodynamic systems, establishing a correlation between internal entropy decrease rate and external entropy production rate. Moreover, it presents a flexible framework for assessing the impact of external factors like changes in world size, path obstacles, and friction. Overall, this research offers a robust, replicable model for studying self-organization processes in any open thermodynamic system. As such, it provides a foundation for further in-depth exploration of the complex behaviors of these systems and contributes to the development of more efficient self-organizing systems across various scientific fields.

Keywords: complexity, self-organization, agent based modelling, efficiency

Procedia PDF Downloads 51

Authors: Rafał Kamiński, Joel Rech, Philippe Bertrand, Christophe Desrayaud

Abstract:

Titanium alloys are among the most important material in the aircraft industry, due to its low density, high strength, and corrosion resistance. However, these alloys are considered as difficult to machine because they have poor thermal properties and high reactivity with cutting tools. The Selective Laser Melting (SLM) process becomes even more popular through industry since it enables the design of new complex components, that cannot be manufactured by standard processes. However, the high temperature reached during the melting phase as well as the several rapid heating and cooling phases, due to the movement of the laser, induce complex microstructures. These microstructures differ from conventional equiaxed ones obtained by casting+forging. Parts obtained by SLM have to be machined in order calibrate the dimensions and the surface roughness of functional surfaces. The ball milling technique is widely applied to finish complex shapes. However, the machinability of titanium is strongly influenced by the microstructure. So the objective of this work is to investigate the influence of the SLM process, i.e. microstructure, on the machinability of titanium, compared to conventional forming processes. The machinability is analyzed by measuring surface roughness, cutting forces, cutting tool wear for a range of cutting conditions (depth of cut ap, feed per tooth fz, spindle speed N) in accordance with industrial practices.

Keywords: ball milling, microstructure, surface roughness, titanium

Procedia PDF Downloads 284

Authors: Esther Simpson, Evans Addo Tetteh

Abstract:

One of the most important sectors in Ghana’s economy is the oil and gas sector. Effective supply chain management is required to ensure the timely delivery of these products to the end users, given the rise in nationwide demand for petroleum products. Contrarily, freight forwarding plays a crucial role in facilitating intra- and intra-country trade, particularly the movement of oil goods. Nevertheless, there has not been enough scientific study done on how marketing, supply chain management, and freight forwarding are integrated in the oil business. By highlighting possible areas for development in the supply chain management of petroleum products, this article seeks to close this gap. The study was predominantly qualitative and featured semi-structured interviews with influential figures in the oil and gas sector, such as marketers, distributors, freight forwarders, and regulatory organizations. The purpose of the interviews was to determine the difficulties and possibilities for enhancing the management of the petroleum products supply chain. Thematic analysis was used to examine the data obtained in order to find patterns and themes that arose. The findings from the study revealed that the oil sector faced a number of issues in terms of supply chain management. Inadequate infrastructure, insufficient storage facilities, a lack of cooperation among parties, and an inadequate regulatory framework were among the obstacles. Furthermore, the study indicated significant prospects for enhancing petroleum product supply chain management, such as the integration of more advanced digital technologies, the formation of strategic alliances, and the adoption of sustainable practices in petroleum product supply chain management. The study's conclusions have far-reaching ramifications for the oil and gas sector, freight forwarding, and Ghana’s economy as a whole. Marketing, supply chain management, and freight forwarding has high prospects from being integrated to improve the efficiency of the petroleum product supply chain, resulting in considerable cost savings for the industry. Furthermore, the use of sustainable practices will improve the industry's sustainability and lessen the environmental effect of the petroleum product supply chain. Based on the findings, we propose that stakeholders in Ghana’s oil and gas sector work together and collaborate to enhance petroleum supply chain management. This collaboration should include the use of digital technologies, the formation of strategic alliances, and the implementation of sustainable practices. Moreover, we urge that governments establish suitable rules to guarantee the efficient and sustainable management of petroleum product supply chains. In conclusion, the integration and combination of marketing, supply chain management, and freight forwarding in the oil business gives a tremendous opportunity for enhancing petroleum product supply chain management. The study's conclusions have far-reaching ramifications for the sector, freight forwarding, and the economy as a whole. Using sustainable practices, integrating digital technology, and forming strategic alliances will improve the efficiency and sustainability of the petroleum product supply chain. We expect that this conference paper will encourage more study and collaboration among oil and gas sector stakeholders to improve petroleum supply chain management.

Keywords: collaboration, logistics, sustainability, supply chain management

Procedia PDF Downloads 70

Authors: F. Adjel, S. Almi, D. Barkat

Abstract:

The synergistic solvent extraction of cobalt (II) from 0.33 mol dm-3 Na2SO4 aqueous solutions with capric acid (HL) in the absence and presence of tri-n-octylphosphine oxide (TOPO) in chloroform at 25°C, has been studied. The extracted species when the capric acid compound was used alone, is CoL2(HL)2. In the presence of TOPO, a remarkable enhancement on the extraction of nickel (II) with 0.02 mol dm-3 capric acid was observed upon the addition of 0.0025 to 0.01 mol dm-3 TOPO in chloroform. From an synergistic extraction- equilibrium study, the synergistic enhancement was ascribed to the adduct formation CoL2(HL)2 n(TOPO). The TOPO-HL interaction strongly influences the synergistic extraction efficiency. The synergistic extraction stoichiometry of cobalt (II) with capric acid and TOPO is studied with the methods of slope analysis. The equilibrium constants were determined.

Keywords: solvent extraction, cobalt (II), capric acid, TOPO, synergism

Procedia PDF Downloads 511

Authors: K. Boualem, T. Yahiaoui, A. Azzi

Abstract:

Numerical investigations are performed to analyze the flow behavior over NACA0015 and to evaluate the efficiency of synthetic jet as active control device. The second objective of this work is to investigate the influence of momentum coefficient of synthetic jet on the flow behaviour. The unsteady Reynolds-averaged Navier-Stokes equations of the turbulent flow are solved using, k-ω SST provided by ANSYS CFX-CFD code. The model presented in this paper is a comprehensive representation of the information found in the literature. Comparison of obtained numerical flow parameters with the experimental ones shows that the adopted computational procedure reflects nearly the real flow nature. Also, numerical results state that use of synthetic jets devices has positive effects on the flow separation, and thus, aerodynamic performance improvement of NACA0015 airfoil. It can also be observed that the use of synthetic jet increases the lift coefficient about 13.3% and reduces the drag coefficient about 52.7%.

Keywords: active control, synthetic jet, NACA airfoil, CFD

Procedia PDF Downloads 300

Authors: Frezer Alem Kebede

Abstract:

The notion of viewing ICT as merely support for the business process has shifted towards viewing ICT as a critical business enabler. As such, the need for ICT devices has increased, contributing to high electronic equipment acquisition and disposal. Hence, its use and disposal must be seen in light of environmental sustainability, i.e., in terms of green use and disposal. However, there are limited studies on green Use and Disposal framework to be used as guiding lens by organizations in developing countries. And this study endeavors to address that need taking one of the largest multinational ICT intensive company in the country. The design and development of this framework passed through several stages, initially factors affecting green use and disposal were identified after quantitative and qualitative data analysis then there were multiple brainstorming sessions for the design enhancement as participative modelling was employed. Given the difference in scope and magnitude of the challenges identified, the proposed framework approaches green use and disposal in four imperatives; strategically, tactically, operationally and through continuous improvement.

Keywords: energy efficiency, green disposal, green ICT, green use, green use and disposal framework, sustainability

Procedia PDF Downloads 189

Authors: Mamdouh Y. Saleh, Gaber El Enany, Medhat H. Elzahar, Mohamed Z. Elshikhipy, Rana Hamouda

Abstract:

The heavy metals pollution in water, sediments and fish of Lake Manzala affected from the disposal of wastewater, industrial and agricultural drainage water into the lake on the environmental situation. A pilot plant with an industrial discharge flow of 135L/h was designed according to the activated sludge plant to simulate between the biological and chemical treatment with the addition of alum to the aeration tank with dosages of 100, 150, 200, and 250 mg/L. The industrial discharge had concentrations of Lead and BOD5 with an average range 1.22, 145mg/L, respectively. That means the average Pb was high up to 25 times than the allowed permissible concentration. The optimization of the chemical-biological process using 200mg/L alum dosage compared has improvement of Lead and BOD5 removal efficiency to 61.76% and 56%, respectively.

Keywords: industrial wastewater, activated sludge, BOD5, lead, alum salt

Procedia PDF Downloads 506

Authors: Brajendra S. Sengar, Vivek Garg, Gaurav Siddharth, Nisheka Anadkat, Amitesh Kumar, Shaibal Mukherjee

Abstract:

The optimal band gap (~ 1 to 1.5 eV) and high absorption coefficient ~104 cm⁻¹ has made Cu₂ZnSn(S,Se)₄ (CZTSSe) films as one of the most promising absorber materials in thin-film photovoltaics. Additionally, CZTSSe consists of elements that are abundant and non-toxic, makes it even more favourable. The CZTSSe thin films are grown at 100 to 500ᵒC substrate temperature (Tsub) on Soda lime glass (SLG) substrate by Elettrorava dual ion beam sputtering (DIBS) system by utilizing a target at 2.43x10⁻⁴ mbar working pressure with RF power of 45 W in argon ambient. The chemical composition, depth profiling, structural properties and optical properties of these CZTSSe thin films prepared on SLG were examined by energy dispersive X-ray spectroscopy (EDX, Oxford Instruments), Hiden secondary ion mass spectroscopy (SIMS) workstation with oxygen ion gun of energy up to 5 keV, X-ray diffraction (XRD) (Rigaku Cu Kα radiation, λ=.154nm) and Spectroscopic Ellipsometry (SE, M-2000D from J. A. Woollam Co., Inc). It is observed that from that, the thin films deposited at Tsub=200 and 300°C show Cu-poor and Zn-rich states (i.e., Cu/(Zn + Sn) < 1 and Zn/Sn > 1), which is not the case for films grown at other Tsub. It has been reported that the CZTSSe thin films with the highest efficiency are typically at Cu-poor and Zn-rich states. The values of band gap in the fundamental absorption region of CZTSSe are found to be in the range of 1.23-1.70 eV depending upon the Cu/(Zn+Sn) ratio. It is also observed that there is a decline in optical band gap with the increase in Cu/(Zn+Sn) ratio (evaluated from EDX measurement). Cu-poor films are found to have higher optical band gap than Cu-rich films. The decrease in the band gap with the increase in Cu content in case of CZTSSe films may be attributed to changes in the extent of p-d hybridization between Cu d-levels and (S, Se) p-levels. CZTSSe thin films with Cu/(Zn+Sn) ratio in the range 0.86–1.5 have been successfully deposited using DIBS. Optical band gap of the films is found to vary from 1.23 to 1.70 eV based on Cu/(Zn+Sn) ratio. CZTSe films with Cu/ (Zn+Sn) ratio of .86 are found to have optical band gap close to the ideal band gap (1.49 eV) for highest theoretical conversion efficiency. Thus by tailoring the value of Cu/(Zn+Sn), CZTSSe thin films with the desired band gap could be obtained. Acknowledgment: We are thankful to DIBS, EDX, and XRD facility equipped at Sophisticated Instrument Centre (SIC) at IIT Indore. The authors B. S. S and A. K. acknowledge CSIR, and V. G. acknowledges UGC, India for their fellowships. B. S. S is thankful to DST and IUSSTF for BASE Internship Award. Prof. Shaibal Mukherjee is thankful to DST and IUSSTF for BASE Fellowship and MEITY YFRF award. This work is partially supported by DAE BRNS, DST CERI, and DST-RFBR Project under India-Russia Programme of Cooperation in Science and Technology. We are thankful to Mukul Gupta for SIMS facility equipped at UGC-DAE Indore.

Keywords: CZTSSe, DIBS, EDX, solar cell

Procedia PDF Downloads 237

Authors: Bakr Gomaa

Abstract:

Wind driven Cross ventilation is achieved when air moves indoors due to the pressure difference on the building envelope. This is especially important in breezy moderate to humid settings in which fast air flow can promote thermal comfort. Studies have shown that the use of simple building forms or ignoring the urban context when studying natural ventilation can lead to inaccurate results. In this paper, the impact of the urban form of a regular array of buildings is investigated to define the impact of this urban setting on cross ventilation potential. The objective of this paper is to provide the necessary tools to achieve natural ventilation for cooling purposes in an array of building blocks context. The array urban form has been studied before for natural ventilation purposes yet to the best of our knowledge no study has considered the relationship between the urban form and the pressure patterns that develop on the buildings envelope for cross ventilation. For this we use detailed weather data for a case study city of Alexandria (Egypt), as well as a validated CFD simulations to investigate the cross ventilation potential in terms of pressure patterns in waterfront as well as in-city wind flows perpendicular to the buildings array. it was found that for both waterfront and in-city wind speeds the windows needed for cross ventilation in rear raws of the array are significantly larger than those needed for front raw.

Keywords: Alexandria, CFD, cross ventilation, pressure coefficient

Procedia PDF Downloads 377

Authors: Azad A. Meerkhan, Alaa Hani Razak, Bayan M. S. Younis

Abstract:

The efficiency of enzyme-linked immunosorbent assay (ELISA) in sheep infected with Fasciola hepatica was studied. 232 jaundiced sheep among 5208 sheep slaughter in the Duhok abattoir (regardless of the age and gender) between the period of May. 2012 to Oct. 2012 were examined by direct examination (Searching of adult flukes in the bile duct) and by Enzyme-linked immunosorbent assay (ELISA) to detect the prevalence of fascioliasis in the studied population which showed a high observed infection ratio in Sep. 2012 (12.2%) with the high (ELISA) result of infection in May. 2012 (25.36%). Significant differences were found between the two ways in all of the months with the highest difference in May. 2012 and the net deference between the both ways was 6.91%.

Keywords: fascioliasis, Fasciola hepatica, layers, liver fluk, ELISA, direct examination

Procedia PDF Downloads 308

Authors: A. M. Al-Sabagh, M. A. Deyab, M. N. Kroush

Abstract:

The present study focused on critical and detailed approach for using aluminum electrode as impressed current anode for cathodic protection of X65 steel tank containing fresh water. The impressed current design calculation showed 0.6 A of current demand and voltage of 0.33 V required to adequately protect the X65 steel tank with internal surface area of 421 m². We used here one transformer rectifier with current and voltage output of 25 A and 25 V, respectively. The data showed that the potentials ranged from -0.474 to -0.509 V (vs. Cu/CuSO₄), prior to the application of cathodic protection. When the potential was measured 1 h after the application of cathodic protection, the potential values showed considerable shift within protection range (-0.950 V vs. Cu/CuSO₄). The results confirmed that aluminum anode can be used in freshwater applications with high efficiency (current capacity) and low consumption rate.

Keywords: cathodic protection, aluminum, steel, fresh water

Procedia PDF Downloads 140

Authors: Neda Jalaliyoon, Nooh Abu Bakar, Hamed Taherdoost

Abstract:

The present research recommended balanced scorecard (BSC) framework to appraise the performance of the universities. As the original model of balanced scorecard has four perspectives in order to implement BSC in present research the same model with “financial perspective”, “customer”,” internal process” and “learning and growth” is used as well. With applying fuzzy Delphi method (FDM) and questionnaire sixteen measures of performance were identified. Moreover, with using the analytic network process (ANP) the weights of the selected indicators were determined. Results indicated that the most important BSC’s aspect were Internal Process (0.3149), Customer (0.2769), Learning and Growth (0.2049), and Financial (0.2033) respectively. The proposed BSC framework can help universities to enhance their efficiency in competitive environment.

Keywords: balanced scorecard, higher education, fuzzy delphi method, analytic network process (ANP)

Procedia PDF Downloads 413

Authors: Liu Yinga, Bai Xingjiab

Abstract:

The conventional way to exploit coalbed methane is to drop reservoirs pressure through drainage, which means that reducing pressure through water drainage for coalbed methane desorption. However, it has many limitations. In this paper, the recovery by conventional way is low, in order to exploit water-sensitive reservoir, combustion of coal seam is proposed to increase recovery ratio, and then theoretical feasibility is elaborated through four aspects: temperature, pressure, superficial area, competitive adsorption, then given an example of water sensitive reservoir, results can be obtained that recovery is effectively improved through combustion of coal seam. At the same time, the suitability and efficiency of combustion of coal seam determine that it can be widely applied.

Keywords: coalbed methane, drainage decompression, water-sensitive, combustion of coal seams, competitive adsorption

Procedia PDF Downloads 251

Authors: Parul Sahu

Abstract:

In recent years, seawater desalination has been emerged as a potential resource to circumvent water scarcity, especially in coastal regions. Among the various methods, thermal evaporation or distillation and membrane operations like Reverse Osmosis (RO) has been exploited at commercial scale. However, the energy cost and maintenance expenses associated with these processes remain high. In this context Freeze Desalination (FD), subjected to the availability of low cost refrigeration, offers an exciting alternative. Liquefied Natural Gas (LNG) regasification terminals provide an opportunity to utilize the refrigeration available with regasification of LNG. This work presents the conceptualization and development of a process scheme integrating the ice and hydrate based FD to the LNG regasification process. This integration overcomes the high energy demand associated with FD processes by utilizing the refrigeration associated with LNG regasification. An optimal process scheme was obtained by performing process simulation using ASPEN PLUS simulator. The results indicated the new proposed process requires only 1 kWh/m³ of energy with the utilization of maximum refrigeration. In addition, a sensitivity analysis was also performed to study the effect of various process parameters on water recovery and energy consumption for the proposed process. The results show that the energy consumption decreases by 30% with an increase in water recovery from 30% to 60%. However, due to operational limitations associated with ice and hydrate handling in seawater, the water recovery cannot be maximized but optimized. The proposed process can be potentially used to desalinate seawater in integration with LNG regasification terminal.

Keywords: freeze desalination, liquefied natural gas regasification, process simulation, refrigeration

Procedia PDF Downloads 117

Authors: T. Martini, J. M. Martínez

Abstract:

An algorithmic acceleration strategy based on quasi-Newton (or secant) methods is displayed for address the practical problem of accelerating the convergence of the Newton-Lagrange method in the case of convergence to critical multipliers. Since the Newton-Lagrange iteration converges locally at a linear rate, it is natural to conjecture that quasi-Newton methods based on the so called secant equation and some minimal variation principle, could converge superlinearly, thus restoring the convergence properties of Newton's method. This strategy can also be applied to accelerate the convergence of algorithms applied to fixed-points problems. Computational experience is reported illustrating the efficiency of this strategy to solve fixed-point problems with linear convergence rate.

Keywords: algorithmic acceleration, fixed-point problems, nonlinear programming, quasi-newton method

Procedia PDF Downloads 476

Authors: G. Andreutti, G. Saccone, D. Lucariello, C. Pirozzi, S. Franchitti, R. Borrelli, C. Toscano, P. Caso, G. Ferraro, C. Pascarella

Abstract:

The reduction of greenhouse gases and pollution emissions is a worldwide environmental issue. The amount of CO₂ released by an aircraft is associated with the amount of fuel burned, so the improvement of engine thermo-mechanical efficiency and specific fuel consumption is a significant technological driver for aviation. Moreover, with the prospect that avgas will be phased out, an engine able to use more available and cheaper fuels is an evident advantage. An advanced aeronautical Diesel engine, because of its high efficiency and ability to use widely available and low-cost jet and diesel fuels, is a promising solution to achieve a more fuel-efficient aircraft. On the other hand, a Diesel engine has generally a higher overall weight, if compared with a gasoline one of same power performances. Fixing the MTOW, Max Take-Off Weight, and the operational payload, this extra-weight reduces the aircraft fuel fraction, partially vinifying the associated benefits. Therefore, an effort in weight saving manufacturing technologies is likely desirable. In this work, in order to achieve the mentioned goals, innovative Electron Beam Melting – EBM, Additive Manufacturing – AM technologies were applied to a two-stroke, common rail, GF56 Diesel engine, developed by the CMD Company for aeronautic applications. For this purpose, a consortium of academic, research and industrial partners, including CMD Company, Italian Aerospace Research Centre – CIRA, University of Naples Federico II and the University of Salerno carried out a technological project, funded by the Italian Minister of Education and Research – MIUR. The project aimed to optimize the baseline engine in order to improve its performance and increase its airworthiness features. This project was focused on the definition, design, development, and application of enabling technologies for performance improvement of GF56. Weight saving of this engine was pursued through the application of EBM-AM technologies and in particular using Arcam AB A2X machine, available at CIRA. The 3D printer processes titanium alloy micro-powders and it was employed to realize new connecting rods of the GF56 engine with an additive-oriented design approach. After a preliminary investigation of EBM process parameters and a thermo-mechanical characterization of titanium alloy samples, additive manufactured, innovative connecting rods were fabricated. These engine elements were structurally verified, topologically optimized, 3D printed and suitably post-processed. Finally, the overall performance improvement, on a typical General Aviation aircraft, was estimated, substituting the conventional engine with the optimized GF56 propulsion system.

Keywords: aeronautic propulsion, additive manufacturing, performance improvement, weight saving, piston engine

Procedia PDF Downloads 131

Authors: Sara Mercedes Barroso Pinzón, Álvaro Jesús Caicedo Castro, Antonio Javer Sánchez Herencia

Abstract:

In recent years there has been increased academic and industrial research into the development of orthopaedic implants with structural properties and functionality similar to mechanical strength, osseointegration, thermal stability and antibacterial capacity similar to bone structure. Hydroxyapatite has been considered for decades as an ideal biomaterial for bone regeneration due to its chemical and crystallographic similarity to the mineral structure bioapatites. However, the lack of trace elements in the hydroxyapatite structure confers very low mechanical and biological properties. Under this scenario, the objective of the research is the synthesis of hydroxyapatite with Mg from the francolite mineral present in phosphate rock from the central-eastern region of Colombia, taking advantage of the extraction of mineral species as natural precursors of Ca, P and Mg. The minerals present were studied, fluorapatite as the mineral of interest associated with magnesium carbonates and quartz. The chemical and mineralogical composition was determined by X-ray fluorescence (XRF) and X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX); the optimum conditions were established using the acid leaching mechanism in the wet concentration process. From the products obtained and characterised by XRD, XRF, SEM, FTIR, RAMAN, HAp-Mg biocomposite scaffolds are fabricated and the influence of Mg on morphometric parameters, mechanical and biological properties in the formed materials is evaluated.

Keywords: phosphate rock, hydroxyapatite, magnesium, biomaterials

Procedia PDF Downloads 40

Authors: Aydin Teymourifar, Gurkan Ozturk

Abstract:

In this paper, a hybrid Tabu Search (TS) algorithm is suggested for the multi-objective job shop scheduling problems (MO-JSSPs). The algorithm integrates several shifting bottleneck based neighborhood structures with the Giffler & Thompson algorithm, which improve efficiency of the search. Diversification and intensification are provided with local and global left shift algorithms application and also new semi-active, active, and non-delay schedules creation. The suggested algorithm is tested in the MO-JSSPs benchmarks from the literature based on the Pareto optimality concept. Different performances criteria are used for the multi-objective algorithm evaluation. The proposed algorithm is able to find the Pareto solutions of the test problems in shorter time than other algorithm of the literature.

Keywords: tabu search, heuristics, job shop scheduling, multi-objective optimization, Pareto optimality

Procedia PDF Downloads 432

Authors: Amirhossein Karamoozian, Desheng Wu, Behzad Abbasnejad

Abstract:

Building information modelling (BIM) is a new technology to enhance the efficiency of project management in the construction industry. In addition to the potential benefits of this useful technology, there are various risks and obstacles to applying it in construction projects. In this study, a decision making approach is presented for risk assessment in BIM adoption in construction projects. Various risk factors of exerting BIM during different phases of the project lifecycle are identified with the help of Delphi method, experts’ opinions and related literature. Afterward, Shannon’s entropy and Fuzzy TOPSIS (Technique for Order Preference by Similarity to Ideal Situation) are applied to derive priorities of the identified risk factors. Results indicated that lack of knowledge between professional engineers about workflows in BIM and conflict of opinions between different stakeholders are the risk factors with the highest priority.

Keywords: risk, BIM, fuzzy TOPSIS, construction projects

Procedia PDF Downloads 214

Authors: Belloufi Mohammed, Sellami Badreddine

Abstract:

Conjugate gradient methods have played a special role for solving large scale optimization problems due to the simplicity of their iteration, convergence properties and their low memory requirements. In this work, we propose a new class of conjugate gradient methods which ensures sufficient descent. Moreover, we propose a new search direction with the Wolfe line search technique for solving unconstrained optimization problems, a global convergence result for general functions is established provided that the line search satisfies the Wolfe conditions. Our numerical experiments indicate that our proposed methods are preferable and in general superior to the classical conjugate gradient methods in terms of efficiency and robustness.

Keywords: unconstrained optimization, conjugate gradient method, sufficient descent property, numerical comparisons

Procedia PDF Downloads 389

Authors: Hiba Akrout, Khaoula Hidouri, Béchir Chaouachi, Romdhane Ben Slama

Abstract:

A simple solar distiller has been constructed in order to desalt water via the solar distillation process. An experimental study has been conducted in June. The aim of this work is to study the effect of the distance between the cold condensing surface and the hot steam generation surface in order to optimize the geometric characteristics of a simple solar still. To do this, we have developed a mathematical model based on thermal and mass equations system. Subsequently, the equations system resolution has been made through a program developed on MATLAB software, which allowed us to evaluate the production of this system as a function of the distance separating the two surfaces. In addition, this model allowed us to determine the evolution of the humid air temperature inside the solar still as well as the humidity ratio profile all over the day. Simulations results show that the solar distiller production, as well as the humid air temperature, are proportional to the global solar radiation. It was also found that the air humidity ratio inside the solar still has a similar evolution of that of solar radiation. Moreover, the solar distiller average height augmentation, for constant water depth, induces the diminution of the production. However, increasing the water depth for a fixed average height of solar distiller reduces the production.

Keywords: distillation, solar energy, heat transfer, mass transfer, average height

Procedia PDF Downloads 134

Authors: Sara Grazhdani, Alma Cili, Arben Ivanaj

Abstract:

Immune Thrombocytopenic Purpura is an autoimmune disease characterized by the destruction of platelets by immune mediators, their deficient production in the red bone marrow and increased splenic sequestration, leading to the appearance of thrombocytopenia and increased risk of hemorrhage. Treatment is indicated in patients with low platelet counts (<30 x 10 9 /L) who present clinically with hemorrhagic events or are at increased risk for hemorrhage. The goal of the treatment remains (I) prevention of hemorrhagic events and deaths resulting from them, (II) reaching an adequate level of the number of platelets, (III) treatment of patients with as few toxic effects as possible. Corticosteroid therapy remains the first choice in the treatment of patients with Primary Immune Thrombocytopenic Purpura. Rituximab (Mabthera) remains the first choice in the second line in the treatment of patients with Immune Thrombocytopenic Purpura, refractory to the use of cortisones.

Keywords: ITP, rituximab, prednisolone, relapse

Procedia PDF Downloads 91

Authors: Sakina Fatima, Joseph-Patrick W. E. Clarke, Patricia A. Thibault, Subha Kalyaanamoorthy, Michael Levin, Aravindhan Ganesan

Abstract:

Heteronuclear ribonucleoprotein (hnRNPA1 or A1) is associated with the pathology of different diseases, including neurological disorders and cancers. In particular, the aggregation and dysfunction of A1 have been identified as a critical driver for neurodegeneration (NDG) in Multiple Sclerosis (MS). Structurally, A1 includes a low-complexity domain (LCD) and two RNA-recognition motifs (RRMs), and their interdomain coordination may play a crucial role in A1 aggregation. Previous studies propose that RNA-inhibitors or nucleoside analogs that bind to RRMs can potentially prevent A1 self-association. Therefore, molecular-level understanding of the structures, dynamics, and nucleotide interactions with A1 RRMs can be useful for developing therapeutics for NDG in MS. In this work, a combination of computational modelling and biochemical experiments were employed to analyze a set of RNA-A1 RRM complexes. Initially, the atomistic models of RNA-RRM complexes were constructed by modifying known crystal structures (e.g., PDBs: 4YOE and 5MPG), and through molecular docking calculations. The complexes were optimized using molecular dynamics simulations (200-400 ns), and their binding free energies were computed. The binding affinities of the selected complexes were validated using a thermal shift assay. Further, the most important molecular interactions that contributed to the overall stability of the RNA-A1 RRM complexes were deduced. The results highlight that adenine and guanine are the most suitable nucleotides for high-affinity binding with A1. These insights will be useful in the rational design of nucleotide-analogs for targeting A1 RRMs.

Keywords: hnRNPA1, molecular docking, molecular dynamics, RNA-binding proteins

Procedia PDF Downloads 104

Authors: Sudawan Somjai

Abstract:

The purpose of this paper was to find an appropriate outsourcing system model for the Thai electrical appliances industry. The objective was to increase competitive capability of the industry with an outsourcing system. The population for this study was the staff in the selected 10 companies in Thai electrical appliances industry located in Bangkok and the eastern part of Thailand. Data collecting techniques included in-depth interviews, focus group and storytelling techniques. The data was collected from 5 key informants from each company, making a total of 50 informants. The findings revealed that an outsourcing model would consist of important factors including outsourcing system, labor flexibility, capability of business process, manpower management efficiency, cost reduction, business risk elimination, core competency and competitiveness. Different suggestions were made as well in this research paper.

Keywords: outsourcing system, model, Thailand, electrical appliances industry

Procedia PDF Downloads 580

Authors: Nasrin Akter, Prem Chhetri, Shams Rahman

Abstract:

The present study tested Ajzen’s Theory of Planned Behavior (TPB) model to explain the formation of business customers’ intention to use 3PL services in Bangladesh. The findings show that the TPB model has a good fit to the data. Based on theoretical support and suggested modification indices, a refined TPB model was developed afterwards which provides a better predictive power for intention. Consistent with the theory, the results of a structural equation analysis revealed that the intention to use 3PL services is predicted by attitude and subjective norms but not by perceived behavioral control. Further investigation indicated that the paths between (attitude and intention) and (subjective norms and intention) did not statistically differ between 3PL user and non-user. Findings of this research provide an evidence base to formulate business strategies to increase the use of 3PL services in Bangladesh to enhance productivity and to gain economic efficiency.

Keywords: Bangladesh, intention, third-party logistics, Theory of Planned Behavior

Procedia PDF Downloads 570

Authors: Takahiro Ishizaki, Shutaro Hisada, Oi Lun Li

Abstract:

Control of surface wettability is very important in various industrial fields. Thus, contact angle hysteresis which is defined as the difference between advancing and receding water contact angles has been paid attention because the surface having low contact angle hysteresis can control wetting behavior of water droplet. Self-assembled monolayer (SAM) formed using organic silane molecules has been used to control surface wettability, in particular, static contact angles, however, the effect of alkyl-chain length in organic silane molecules on the contact angle hysteresis has not yet clarified. In this study, we aimed to investigate the effect of alkyl-chain length (C1-C18) in organic silane molecules on the contact angle hysteresis. SAMs were formed on Si wafer by thermal CVD method using silane coupling agents having different alkyl-chain length. The static water contact angles increased with an increase in the alkyl-chain length. On the other hand, although the water contact angle hysteresis tended to decrease with an increase in the alkyl-chain length, in case of the alkyl-chain length of more than C16 the contact angle hysteresis increased. This could be due to the decrease in the molecular mobility because of the increase in the molecular packing density in chemisorbed silane molecules.

Keywords: alkyl-chain length, self-assembled monolayer, silane coupling agent, surface wettability

Procedia PDF Downloads 373