Search results for: recovery ratio

Authors: Anurag Bhambhani, Jan Peter Van Der Hoek, Zoran Kapelan

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The food system depends on the availability of Phosphorus (P) and Nitrogen (N). Growing population, depleting Phosphorus reserves and energy-intensive industrial nitrogen fixation are threats to their future availability. Recovering P and N from domestic sewage water offers a solution. Recovered P and N can be applied to agricultural land, replacing virgin P and N. Thus, recovery from sewage water offers a solution befitting a circular economy. To ensure minimum waste and maximum resource efficiency a circularity assessment method is crucial to optimize nutrient flows and minimize losses. Material Circularity Indicator (MCI) is a useful method to quantify the circularity of materials. It was developed for materials that remain within the market and recently extended to include biotic materials that may be composted or used for energy recovery after end-of-use. However, MCI has not been used in the context of nutrient recovery. Besides, MCI is time-static, i.e., it cannot account for dynamic systems such as the terrestrial nutrient cycles. Nutrient application to agricultural land is a highly dynamic process wherein flows and stocks change with time. The rate of recycling of nutrients in nature can depend on numerous factors such as prevailing soil conditions, local hydrology, the presence of animals, etc. Therefore, a dynamic model of nutrient flows with indicators is needed for the circularity assessment. A simple substance flow model of P and N will be developed with the help of flow equations and transfer coefficients that incorporate the nutrient recovery step along with the agricultural application, the volatilization and leaching processes, plant uptake and subsequent animal and human uptake. The model is then used for calculating the proportions of linear and restorative flows (coming from reused/recycled sources). The model will simulate the adsorption process based on the quantity of adsorbent and nutrient concentration in the water. Thereafter, the application of the adsorbed nutrients to agricultural land will be simulated based on adsorbate release kinetics, local soil conditions, hydrology, vegetation, etc. Based on the model, the restorative nutrient flow (returning to the sewage plant following human consumption) will be calculated. The developed methodology will be applied to a case study of resource recovery from wastewater. In the aforementioned case study located in Italy, biochar or zeolite is to be used for recovery of P and N from domestic sewage through adsorption and thereafter, used as a slow-release fertilizer in agriculture. Using this model, information regarding the efficiency of nutrient recovery and application can be generated. This can help to optimize the recovery process and application of the nutrients. Consequently, this will help to optimize nutrient recovery and application and reduce the dependence of the food system on the virgin extraction of P and N.

Keywords: circular economy, dynamic substance flow, nutrient cycles, resource recovery from water

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Authors: Hammam Aljabri, Hong G. Im

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Hydrogen is a promising future fuel to support the transition of the energy sector toward carbon neutrality. The direct utilization of H2 in Internal Combustion Engines (ICEs) is possible, and this technology faces mainly two challenges; high NOx emissions and severe knocking at mid to high loads. In this study, we numerically investigated the potential of H2 combustion in a truck-size engine operated in SI mode. To mitigate the knocking nature of H2 combustion, we have focused on studying the effects of three primary parameters; the compression ratio (CR), the air-fuel ratio, and the spark time. The baseline case was set using a CR of 16.5 and an equivalence ratio of 0.35. In simulations, the auto-ignition tendency was evaluated based on the maximum pressure rise rate and the local pressure fluctuations at the monitoring points set along the wall of the combustion chamber. To mitigate the auto-ignition tendency while enabling a wider range of engine operation, the effect of lowering the compression ratio was assessed. The results indicate that by lowering the compression ratio from 16.5:1 to 12.5:1, an indicated thermal efficiency of 47.5% can be achieved. Aiming to restrain the auto-ignition while maintaining good efficiency, a reduction in the equivalence ratio was examined under different compression ratios. The result indicates that higher compression ratios will require lower equivalence ratios, and due to practical limitations, a lower equivalence ratio of 0.25 was set as the limit. Using a compression ratio of 13.5 combined with an equivalence ratio of 0.3 resulted in an indicated thermal efficiency of 48.6%, that is, at a fixed spark time. It is found that under such lean conditions, the incomplete combustion losses and exhaust losses were high. Thus, advancing the spark time was assessed as a possible solution. The results demonstrated the advantages of advancing the spark time, where an indicated thermal efficiency exceeding 50% was achieved using a compression ratio of 14.5:1 and an equivalence ratio of 0.25.

Keywords: hydrogen, combustion, engine knock, SI engine

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Authors: Kharisma Utomo Mulyodinoto, Suwarno, A. Abu-Siada

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Dissolved Gas Analysis is one of impressive technique to detect and predict internal fault of transformers by using gas generated by transformer oil sample. A number of methods are used to interpret the dissolved gas from transformer oil sample: Doernenberg Ratio Method, IEC (International Electrotechnical Commission) Ratio Method, and Duval Triangle Method. While the assessment of dissolved gas within transformer oil samples has been standardized over the past two decades, analysis of the results is not always straight forward as it depends on personnel expertise more than mathematical formulas. To get over this limitation, this paper is aimed at improving the interpretation of Doernenberg Ratio Method, IEC Ratio Method, and Duval Triangle Method using Two Stages Adaptive Neuro-Fuzzy Inference System (ANFIS). Dissolved gas analysis data from 520 faulty transformers was analyzed to establish the proposed ANFIS model. Results show that the developed ANFIS model is accurate and can standardize the dissolved gas interpretation process with accuracy higher than 90%.

Keywords: ANFIS, dissolved gas analysis, Doernenberg ratio method, Duval triangular method, IEC ratio method, transformer

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Authors: Zhiyuan Jia, Xiuxiu Sun, Yong Chen, Liu Hai, Shuangqing Li

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The engine cooling water and exhaust gas contain a large amount of available energy. In order to improve energy efficiency, a steam injection technology based on waste heat recovery is proposed. The models of cooling water waste heat utilization, exhaust gas waste heat utilization, and exhaust gas-cooling water waste heat utilization were constructed, and the effects of the three modes on the performance of steam injection were analyzed, and then the feasibility of in-cylinder water injection steam technology based on waste heat recovery was verified. The research results show that when the injection water flow rate is 0.10 kg/s and the temperature is 298 K, at a cooling water temperature of 363 K, the maximum temperature of the injection water heated by the cooling water can reach 314.5 K; at an exhaust gas temperature of 973 K and an exhaust gas flow rate of 0.12 kg/s, the maximum temperature of the injection water heated by the exhaust gas can reach 430 K; Under the condition of cooling water temperature of 363 K, exhaust gas temperature of 973 K and exhaust gas flow rate of 0.12 kg/s, after cooling water and exhaust gas heating, the maximum temperature of the injection water can reach 463 K. When the engine is 1200 rpm, the water injection volume is 30 mg, and the water injection time is 36°CA, the engine power increases by 2% and the fuel consumption is reduced by 2.6%.

Keywords: cooling water, exhaust gas, extended range engine, steam injection, waste heat recovery

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Authors: J. A. Louw Coetzee, Josua P. Meyer

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The thermodynamic properties of different refrigerants in combination with the variation in geometrical properties (hydraulic diameter, aspect ratio, and inclination angle) of a rectangular microchannel determine the two-phase frictional pressure gradient. The effect of aspect ratio on frictional pressure drop had not been investigated enough during adiabatic two-phase flow and condensation in rectangular microchannels. This experimental study was concerned with measurement of the frictional pressure gradient in a rectangular microchannel, with hydraulic diameter of 900 μm. The aspect ratio of this microchannel was varied over a range that stretched from 0.3 to 3 in order to capture the effect of aspect ratio variation. A commonly used refrigerant, R134a, was used in the tests that spanned over a mass flux range of 100 to 1000 kg m-2 s-1 as well as the whole vapour quality range. This study formed part of a refrigerant condensation experiment and was therefore conducted at a saturation temperature of 40 °C. The study found that there was little influence of the aspect ratio on the frictional pressure drop at the test conditions. The data was compared to some of the well known micro- and macro-channel two-phase pressure drop correlations. Most of the separated flow correlations predicted the pressure drop data well at mass fluxes larger than 400 kg m-2 s-1 and vapour qualities above 0.2.

Keywords: aspect ratio, microchannel, two-phase, pressure gradient

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Authors: Rashid S. Mohammad, Shicheng Zhang, Sun Lu, Syed Jamal-Ud-Din, Xinzhe Zhao

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A compositional reservoir simulation model (CMG-GEM) was used for cyclic CO₂ injection process in unconventional tight reservoir. Cyclic CO₂ injection is an enhanced oil recovery process consisting of injection, shut-in, and production. The study of cyclic CO₂ injection and hydrocarbon recovery in ultra-low permeability reservoirs is mainly a function of rock, fluid, and operational parameters. CMG-GEM was used to study several design parameters of cyclic CO₂ injection process to distinguish the parameters with maximum effect on the oil recovery and to comprehend the behavior of cyclic CO₂ injection in tight reservoir. On the other hand, permeability reduction induced by asphaltene precipitation is one of the major issues in the oil industry due to its plugging onto the porous media which reduces the oil productivity. In addition to asphaltene deposition, solubility of CO₂ in the aquifer is one of the safest and permanent trapping techniques when considering CO₂ storage mechanisms in geological formations. However, the effects of the above uncertain parameters on the process of CO₂ enhanced oil recovery have not been understood systematically. Hence, it is absolutely necessary to study the most significant parameters which dominate the process. The main objective of this study is to improve techniques for designing cyclic CO₂ injection process while considering the effects of asphaltene deposition and solubility of CO₂ in the brine in order to prevent asphaltene precipitation, minimize CO₂ emission, optimize cyclic CO₂ injection, and maximize oil production.

Keywords: tight reservoirs, cyclic O₂ injection, asphaltene, solubility, reservoir simulation

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Authors: A. Benmerkhi, A. Bounouioua, M. Bouchemat, T. Bouchemat

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In this paper, we present a numerical optical properties of a triangular periodic lattice of elliptical air holes. We report the influence of the ratio (semi-major axis length of elliptical hole to the filling ratio) on the photonic band gap. Then by using the finite difference time domain (FDTD) algorithm, the resonant wavelength of the point defect microcavities in a two-dimensional photonic crystal (PC) shifts towards the low wavelengths with significantly increased filing ratio. It can be noted that the Q factor is gradually changed to higher when the filling ratio increases. It is due to an increase in reflectivity of the PC mirror. Also we theoretically investigate the H1 cavity, where the value of semi-major axis (Rx) of the six holes surrounding the cavity are fixed at 0.5a and the Rx of the two edge air holes are fixed at the optimum value of 0.52a. The highest Q factor of 4.1359 × 10⁶ is achieved at the resonant mode located at λ = 1.4970 µm.

Keywords: photonic crystal, microcavity, filling ratio, elliptical holes

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Authors: Rabitah Zakaria, Chan M. Luan, Nor Hakimah Ramly

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The extraction of vegetable oil using aqueous extraction process assisted by ionic extended surfactant has been investigated as an alternative to hexane extraction. However, the ionic extended surfactant has not been commercialised and its safety with respect to food processing is uncertain. Hence, food-grade non-ionic surfactants (Tween 20, Span 20, and Span 80) were proposed for the extraction of residual oil from palm-pressed mesocarp fibre. Palm-pressed mesocarp fibre contains a significant amount of residual oil ( 5-10 wt %) and its recovery is beneficial as the oil contains much higher content of vitamin E, carotenoids, and sterols compared to crude palm oil. In this study, the formulation of food-grade surfactants using a combination of high hydrophilic-lipophilic balance (HLB) surfactants and low HLB surfactants to produce micro-emulsion with very low interfacial tension (IFT) was investigated. The suitable surfactant formulation was used in the oil extraction process and the efficiency of the extraction was correlated with the IFT, droplet size and viscosity. It was found that a ternary surfactant mixture with a HLB value of 15 (82% Tween 20, 12% Span 20 and 6% Span 80) was able to produce micro-emulsion with very low IFT compared to other HLB combinations. Results suggested that the IFT and droplet size highly affect the oil recovery efficiency. Finally, optimization of the operating parameters shows that the highest extraction efficiency of 78% was achieved at 1:31 solid to liquid ratio, 2 wt % surfactant solution, temperature of 50˚C, and 50 minutes contact time.

Keywords: food-grade surfactants, aqueous extraction of residual oil, palm-pressed mesocarp fibre, interfacial tension

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Authors: B. V. Lande, Suhas Kongare

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Fuel blend of alcohol and conventional hydrocarbon fuels for a spark ignition engine can increase the fuel octane rating and the power for a given engine displacement and compression ratio. The greatest advantage of ethanol as a fuel in SI Engines is its high octane number. The efficiency of an SI engine that is the ability to convert fuel energy to mechanical energy, mainly depends on the compression ratio. It is, therefore, an advantage to increase this as much as possible. The major restraint is the fuel octane number – high octane fuels can be used with high compression ratios, thus yielding higher energy efficiency. This work investigates to suggest suitable ethanol gasoline blend and compression ratio for single cylinder four strokes SI Engine on the basis of performance and exhaust emissions. A single cylinder four stroke SI Engine was tested with different blend of ethanol – gasoline like E5 (5% ethanol +95% gasoline), E10 (10% ethanol + 90% gasoline) E15 (15% ethanol + 85% petrol) and E20 ( 20% + 80% gasoline) with Variable compression ratio. The performance parameter evaluated BSFC, Brake thermal efficiency and also exhaust emission CO2, Co & HC%. The result showed that higher compression ratio improved engine Performance and reduction in exhaust emission.

Keywords: blend, compression ratio, ethanol, performance, blend

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Authors: Ho Yuan-Hong, Huang Chiung-Ju

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This study conducts simulation analyses to find the optimal debt ceiling of Taiwan, while factoring in welfare maximization under a dynamic stochastic general equilibrium framework. The simulation is based on Taiwan's 2001 to 2011 economic data and shows that welfare is maximized at a "debt"⁄"GDP" ratio of 0.2, increases in the "debt"⁄"GDP " ratio leads to increases in both tax and interest rates and decreases in the consumption ratio and working hours. The study results indicate that the optimal debt ceiling of Taiwan is 20% of GDP, where if the "debt"⁄"GDP" ratio is greater than 40%, the welfare will be negative and result in welfare loss.

Keywords: debt sustainability, optimal debt ceiling, dynamic stochastic general equilibrium, welfare maximization

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Authors: L. Gómez-Limia, I. Franco, T. Blanco, S. Martínez

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European eels (Anguilla anguilla) belong to Anguilliformes order and Anguillidae family. They are generally classified as warm-water fish. Eels have a great commercial value in Europe and Asian countries. Eels can reach high weights, although their commercial size is relatively low in some countries. The capture of larger eels would facilitate the recovery of the species, as well as having a greater number of either glass eels or elvers for aquaculture. In the last years, the demand and the price of eels have increased significantly. However, European eel is considered critically endangered by the International Union for the Conservation of Nature (IUCN) Red List. The biochemical composition of fishes is an important aspect of quality and affects the nutritional value and consumption quality of fish. In addition, knowing this composition can help predict an individual’s condition for their recovery. Fish is known to be important source of protein rich in essential amino acids. However, there is very little information about changes in amino acids composition of European eels with increase in size. The aim of this study was to evaluate the effect of two different weight categories on the amino acids content in muscle tissue of wild European eels. European eels were caught in River Ulla (Galicia, NW Spain), during winter. The eels were slaughtered in ice water immersion. Then, they were purchased and transferred to the laboratory. The eels were subdivided into two groups, according to the weight. The samples were kept frozen (-20 °C) until their analysis. Frozen eels were defrosted and the white muscle between the head and the anal hole. was extracted, in order to obtain amino acids composition. Thirty eels for each group were used. Liquid chromatography was used for separation and quantification of amino a cids. The results conclude that the eels are rich in glutamic acid, leucine, lysine, threonine, valine, isoleucine and phenylalanine. The analysis showed that there are significant differences (p < 0.05) among the eels with different sizes. Histidine, threonine, lysine, hydroxyproline, serine, glycine, arginine, alanine and proline were higher in small eels. European eels muscle presents between 45 and 46% of essential amino acids in the total amino acids. European eels have a well-balanced and high quality protein source in the respect of E/NE ratio. However, eels with higher weight showed a better ratio of essential and non-essential amino acid.

Keywords: European eels, amino acids, HPLC, body size

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Authors: Eugueni Romantchik, Gilbero Lopez, Diego Terrazas

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The residual wind energy recovery from axial air extractors in greenhouses represents a constant source of clean energy production, which reduces production costs by reducing energy consumption costs. The objective of this work is to design, build and evaluate a residual wind energy recovery system. This system consists of a wind turbine placed at an optimal distance, a cone in the air discharge and a mechanism to vary the blades angle of the wind turbine. The system energy balance was analyzed, measuring the main energy parameters such as voltage, amperage, air velocities and angular speeds of the rotors. Tests were carried in a greenhouse with extractor Multifan 130 (1.2 kW, 550 rpm and 1.3 m of diameter) without cone and with cone, with the wind turbine (3 blades with 1.2 m in diameter). The implementation of the system allowed recovering up to 55% of the motor's energy. With the cone installed, the electric energy recovered was increased by 10%. Experimentally, it was shown that changing in 3 degrees the original angle of the wind turbine blades, the angular velocity increases 17.7%.

Keywords: air energy, exhaust fan, greenhouse, wind turbine

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Authors: M. Shahzad Kamal, Abdullah S. Sultan, Usamah A. Al-Mubaiyedh, Ibnelwaleed A. Hussein

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Oil recovery from reservoirs using conventional oil recovery techniques like water flooding is less than 20%. Enhanced oil recovery (EOR) techniques are applied to recover additional oil. Surfactant-polymer flooding is a promising EOR technique used to recover residual oil from reservoirs. Water soluble polymers are used to increase the viscosity of displacing fluids. Surfactants increase the capillary number by reducing the interfacial tension between oil and displacing fluid. Hydrolyzed polyacrylamide (HPAM) is widely used in polymer flooding applications due to its low cost and other desirable properties. HPAM works well in low-temperature and low salinity-environment. In the presence of salts HPAM viscosity decrease due to charge screening effect and it can precipitate at high temperatures in the presence of salts. Various strategies have been adopted to extend the application of water soluble polymers to high-temperature high-salinity (HTHS) reservoir. These include addition of monomers to acrylamide chain that can protect it against thermal hydrolysis. In this work, rheological properties of various water soluble polymers were investigated to find out suitable polymer and surfactant-polymer systems for HTHS reservoirs. Polymer concentration ranged from 0.1 to 1 % (w/v). Effect of temperature, salinity and polymer concentration was investigated using both steady shear and dynamic measurements. Acrylamido tertiary butyl sulfonate based copolymer showed better performance under HTHS conditions compared to HPAM. Moreover, thermoviscosifying polymer showed excellent rheological properties and increase in the viscosity was observed with increase temperature. This property is highly desirable for EOR application.

Keywords: rheology, polyacrylamide, salinity, enhanced oil recovery, polymer flooding

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Authors: Huanhuan Zhao, Bryony J. James

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The relationship between the non-fat solid ratio and bloom formation in untempered chocolate was investigated using two types of chocolate: model chocolate made of varying cocoa powder ratios (46, 49.5 and 53%) and cocoa butter, and commercial Lindt chocolate with varying cocoa content (70, 85 and 90%). X-ray diffraction and colour measurement techniques were used to examine the polymorphism of cocoa butter and the surface whiteness index (WI), respectively. The polymorphic transformation of cocoa butter was highly correlated with the changes of WI during 30 days of storage since it led to the redistribution of fat within the chocolate matrix and resulted in a bloomed surface. The change in WI indicated a similar bloom rate in the chocolates, but the model chocolates with a higher cocoa powder ratio had more pronounced total bloom. This is due to a higher ratio of non-fat solid particles on the surface resulting in microscopic changes in morphology. The ratio of non-fat solids is an important factor in determining the extent of bloom but not the bloom rate.

Keywords: untempered chocolate, microstructure of bloom, polymorphic transformation, surface whiteness

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Authors: Fatemeh Saadat Ghareh Bagh, Srimanta Ray, Jerald Lalman

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Lignin, the largest inventory of organic carbon with a high caloric energy value is a major component in woody and non-woody biomass. In pulping mills, a large amount of the lignin is burned for energy. At the same time, the phenolic structure of lignin enables it to be converted to value-added compounds.This study has focused on extracting lignin from black liquor using deep eutectic solvents (DESs). Therefore, three choline chloride (ChCl)-DESs paired with lactic acid (LA) (1:11), oxalic acid.2H₂O (OX) (1:4), and malic acid (MA) (1:3) were synthesized at 90oC and atmospheric pressure. The kinetics of lignin recovery from black liquor using DES was investigated at three moderate temperatures (338, 353, and 368 K) at time intervals from 30 to 210 min. The extracted lignin (acid soluble lignin plus Klason lignin) was characterized by Fourier transform infrared spectroscopy (FTIR). The FTIR studies included comparing the extracted lignin with a model Kraft lignin. The extracted lignin was characterized spectrophotometrically to determine the acid soluble lignin (ASL) [TAPPI UM 250] fraction and Klason lignin was determined gravimetrically using TAPPI T 222 om02. The lignin extraction reaction using DESs was modeled by first-order reaction kinetics and the activation energy of the process was determined. The ChCl:LA-DES recovered lignin was 79.7±2.1% at 368K and a DES:BL ratio of 4:1 (v/v). The quantity of lignin extracted for the control solvent, [emim][OAc], was 77.5+2.2%. The activation energy measured for the LA-DES system was 22.7 KJ mol⁻¹, while the activation energy for the OX-DES and MA-DES systems were 7.16 KJ·mol⁻¹ and 8.66 KJ·mol⁻¹ when the total lignin recovery was 75.4 ±0.9% and 62.4 ±1.4, % respectively.

Keywords: black liquor, deep eutectic solvents, kinetics, lignin

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Authors: Pavel Bulai, Taras Pitlik, Tatsiana Kulahava, Timofei Lipski

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The method of Electrocardiography (ECG) interpretation for post-exercise recovery tracking was developed. Metabolic indices (aerobic and anaerobic) were designed using ECG-derived features. This study reports the associations between aerobic and anaerobic indices and classical parameters of the person’s physiological state, including blood biochemistry, glycogen concentration and VO2max changes. During the study 9 participants, healthy, physically active medium trained men and women, which trained 2-4 times per week for at least 9 weeks, fulfilled (i) ECG monitoring using Apple Watch Series 4 (AWS4); (ii) blood biochemical analysis; (iii) maximal oxygen consumption (VO2max) test, (iv) bioimpedance analysis (BIA). ECG signals from a single-lead wrist-wearable device were processed with detection of QRS-complex. Aerobic index (AI) was derived as the normalized slope of QR segment. Anaerobic index (ANI) was derived as the normalized slope of SJ segment. Biochemical parameters, glycogen content and VO2max were evaluated eight times within 3-60 hours after training. ECGs were recorded 5 times per day, plus before and after training, cycloergometry and BIA. The negative correlation between AI and blood markers of the muscles functional status including creatine phosphokinase (r=-0.238, p < 0.008), aspartate aminotransferase (r=-0.249, p < 0.004) and uric acid (r = -0.293, p<0.004) were observed. ANI was also correlated with creatine phosphokinase (r= -0.265, p < 0.003), aspartate aminotransferase (r = -0.292, p < 0.001), lactate dehydrogenase (LDH) (r = -0.190, p < 0.050). So, when the level of muscular enzymes increases during post-exercise fatigue, AI and ANI decrease. During recovery, the level of metabolites is restored, and metabolic indices rising is registered. It can be concluded that AI and ANI adequately reflect the physiology of the muscles during recovery. One of the markers of an athlete’s physiological state is the ratio between testosterone and cortisol (TCR). TCR provides a relative indication of anabolic-catabolic balance and is considered to be more sensitive to training stress than measuring testosterone and cortisol separately. AI shows a strong negative correlation with TCR (r=-0.437, p < 0.001) and correctly represents post-exercise physiology. In order to reveal the relation between the ECG-derived metabolic indices and the state of the cardiorespiratory system, direct measurements of VO2max were carried out at various time points after training sessions. The negative correlation between AI and VO2max (r = -0.342, p < 0.001) was obtained. These data testifying VO2max rising during fatigue are controversial. However, some studies have revealed increased stroke volume after training, that agrees with findings. It is important to note that post-exercise increase in VO2max does not mean an athlete’s readiness for the next training session, because the recovery of the cardiovascular system occurs over a substantially longer period. Negative correlations registered for ANI with glycogen (r = -0.303, p < 0.001), albumin (r = -0.205, p < 0.021) and creatinine (r = -0.268, p < 0.002) reflect the dehydration status of participants after training. Correlations between designed metabolic indices and physiological parameters revealed in this study can be considered as the sufficient evidence to use these indices for assessing the state of person’s aerobic and anaerobic metabolic systems after training during fatigue, recovery and supercompensation.

Keywords: aerobic index, anaerobic index, electrocardiography, supercompensation

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Authors: Sewon Kim, Chang Yeop Lee, Minjun Kwon

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This study is aiming at establishing the relationship between the optical signal of flame and an equivalent ratio of flame. In this experiment, flame optical signal in a furnace is measured using photodiode. The combustion system which is composed of metal fiber burner and vertical furnace and flame chemiluminescence is measured at various experimental conditions. In this study, the flame chemiluminescence of laminar premixed flame is measured by using commercially available photodiode. It is experimentally investigated the relationship between equivalent ratio and photodiode signal. In addition, The strategy of combustion control method is proposed by using the optical signal and fuel pressure. The results showed that certain relationship between optical data of photodiode and equivalence ratio exists and this leads to the successful application of this system for instantaneous measurement of equivalence ration of the combustion system.

Keywords: flame chemiluminescence, photo diode, equivalence ratio, combustion control

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Authors: Young Min Kim, Dong Gil Shin, Assmelash Assefa Negash

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This study describes the application of a single loop organic Rankine cycle (ORC) for recovering waste heat from an excavator. In the case of waste heat recovery of the excavator, the heat of hydraulic oil can be used in the ORC system together with the other waste heat sources including the exhaust gas and engine coolant. The performances of four different cases of single loop ORC systems were studied at the main operating condition, and critical design factors are studied to get the maximum power output from the given waste heat sources. The energy and exergy analysis of the cycles are performed concerning the available heat source to determine the best fluid and system configuration. The analysis demonstrates that the ORC in the excavator increases 14% of the net power output at the main operating condition with a simpler system configuration at a lower expander inlet temperature than in a conventional vehicle engine without the heat of the hydraulic oil.

Keywords: engine, excavator, hydraulic oil, organic Rankine cycle (ORC), waste heat recovery

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Authors: Kimberly Joyce A. Roguis, Mica Lorraine L. Fernando, Alan Vito B. Macadangdang, Jennina Mari C. Mijares, Maria Carinnes A. Gonzalez

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The paper showcases the vulnerability of the tourism industry especially the inevitable occurrence of natural disasters, implicating the necessity for post-disaster analysis on tourist attractions. This study discusses the aftermath of the super typhoon ‘Yolanda’ incident in the locality of Coron Island, Palawan, assessing its general effect on the community and its tourism livelihood through the analysis of responses from key role-players in the tourism industry of the area gathered through semi-structured interviews and direct observation. The local government’s instigation of recovery programs to their locality has been a pivotal factor in reviving the vitality of their tourism industry and the involvement of the community has been the determining condition that shifted the industry towards revival a year after the incidence. The study illuminates the disaster mitigation processes in the local tourism livelihood perspective, predominantly the diving industry. It did not suffer physical damage to a great extent but was affected because of the public imagery the disaster brought upon. Collaboration between the local government and the community is the highlight of the research for they maneuvered recovery revealing that cooperation between these two parties bridged the correlation of recovery to tourism development. The disaster paved way to a stance towards promoting progressive tourism outlooks, raising awareness among the public and private sectors and re-assessment of the tourism vitality in their locality. The mayhem and destruction proved to be a liberating creative process to give way to progression and was deemed to be of high significance in the over-all tourism system process despite its impediments in the case of the tourism industry in Coron, Palawan.

Keywords: disaster recovery, tourism development, diving, Palawan

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Authors: Tirtha Raj Dhakal, Brian Davidson, Bob Farquharson

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Institutional design is an important aspect in efficient water resource management. In Nepal, the water supply in both farmers’- and agency-managed irrigation systems has become sub-standard because of the weak institutional framework. This study characterizes both forms of the schemes and links existing institution and governance of the schemes with its performance with reference to cost recovery, maintenance of the schemes and water distribution throughout the schemes. For this, two types of surveys were conducted. A management survey of ten farmers’-managed and five agency-managed schemes of Chitwan valley and its periphery was done. Also, a farm survey comprising 25 farmers from each of head, middle and tail regions of both schemes; Narayani Lift Irrigation Project (agency-managed) and Khageri Irrigation System (farmers’-managed) of Chitwan Valley as a case study was conducted. The results showed that cost recovery of agency-managed schemes in 2015 was less than two percent whereas service fee collection rate in farmers’-managed schemes was nearly 2/3rd that triggered poor maintenance of the schemes and unequal distribution of water throughout the schemes. Also, the institution on practice is unable to create any incentives for farmers for economical use of water as well as willingness to pay for its use. This, thus, compels the need of refined institutional framework which has been suggested in this paper aiming to improve the cost recovery and better water distribution throughout the irrigation schemes.

Keywords: cost recovery, governance, institution, schemes' performance

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Authors: Tomotaka Aoki, Isao Tomita

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We examined the on-off ratio and frequency components of output signals from an electron-interference device made of GaAs/AlₓGa₁₋ₓAs by solving the time-dependent Schrödinger's equation on conducting electrons in the channel waveguide of the device. For electron-wave modulation, a periodic voltage of frequency f was applied to the channel. Furthermore, we examined the voltage-amplitude dependence of the signals in time and frequency domains and found that large applied voltage deformed the output-signal waveform and created additional side modes (frequencies) near the modulation frequency f and that there was a trade-off between on-off ratio and side-mode creation.

Keywords: electrical conduction, electron interference, frequency spectrum, on-off ratio

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Authors: Alireza Bahramian

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High-purity TiO₂ nanoparticles (NPs) with size ranging between 50 nm and 100 nm are synthesized from titanium slag through sulphate route under sonochemical procedure. The effect of dissolution parameters such as the sulfuric acid/slag weight ratio, caustic soda concentration, digestion temperature and time, and initial particle size of the dried slag on the extraction efficiency of TiO₂ and removal of iron are examined. By optimizing the digestion conditions, a rutile TiO₂ powder with surface area of 42 m²/g and mean pore diameter of 22.4 nm were prepared. A thermo-kinetic analysis showed that the digestion temperature has an important effect, while the acid/slag weight ratio and initial size of the slag has a moderate effect on the dissolution rate. The shrinking-core model including both chemical surface reaction and surface diffusion is used to describe the leaching process. A low value of activation energy, 38.12 kJ/mol, indicates the surface chemical reaction model is a rate-controlling step. The kinetic analysis suggested a first order reaction mechanism with respect to the acid concentrations.

Keywords: TiO₂ nanoparticles, titanium slag, dissolution rate, sonochemical method, thermo-kinetic study

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Authors: Sarita Magu, Deepak Singh

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Study Design: This prospective study was conducted at the department of Radio Diagnosis, at Pt B.D. Sharma PGIMS, Rohtak in 57 patients of spine injury on radiographs or radiographically normal patients with neurological deficits presenting within 72 hours of injury. Aims: Evaluation of the role of Magnetic Resonance Imaging (MRI) in Spinal Trauma Patients and to compare MRI findings with clinical profile and neurological status of the patient and to correlate the MRI findings with neurological recovery of the patient and predict the outcome. Material and Methods: Neurological status of patients was assessed at the time of admission and discharge in all the patients and at long term interval of six months to one year in 27 patients as per American spine injury association classification (ASIA). On MRI cord injury was categorized into cord hemorrhage, cord contusion, cord edema only, and normal cord. Quantitative assessment of injury on MRI was done using mean canal compromise (MCC), mean spinal cord compression (MSCC) and lesion length. Neurological status at admission and neurological recovery at discharge and long term follow up was compared with various qualitative cord findings and quantitative parameters on MRI. Results: Cord edema and normal cord was associated with favorable neurological outcome. Cord contusion show lesser neurological recovery as compared to cord edema. Cord hemorrhage was associated with worst neurological status at admission and poor neurological recovery. Mean MCC, MSCC, and lesion length values were higher in patients presenting with ASIA A grade injury and showed decreasing trends towards ASIA E grade injury. Patients showing neurological recovery over the period of hospital stay and long term follow up had lower mean MCC, MSCC, and lesion length as compared to patients showing no neurological recovery. The data was statistically significant with p value <.05. Conclusion: Cord hemorrhage and higher MCC, MSCC and lesion length has poor prognostic value in spine injury patients.

Keywords: spine injury, cord hemorrhage, cord contusion, MCC, MSCC, lesion length, ASIA grading

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Authors: S. S. Chong, A. R. Abdul Aziz, S. W. Harun, H. Arof

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A miniaturized non-adiabatic silica microfiber is proposed for biological oxygen demand (BOD) ratio chemical oxygen demand (COD) sensing for the first time. BOD and COD are two main parameters to justify quality of wastewater. A ratio, BOD:COD can usually be established between the two analytical methods once COD and BOD value has been gathered. This ratio plays a vital role to determine appropriate strategy in wastewater treatment. A non-adiabatic microfiber sensor was formed by tapering the SMF to generate evanescent field where sensitive to perturbation of sensing medium. Because difference ratio BOD and COD contain in solution, this may induced changes of effective refractive index between microfiber and sensing medium. Attenuation wavelength shift to right with 0.5 nm and 3.5 nm while BOD:COD equal to 0.09 and 0.18 respectively. Significance difference wavelength shift may relate with the biodegradability of analyte. This proposed sensor is compact, reliable and feasible to determine the BOD:COD. Further research and investigation should be proceeded to enhance sensitivity and precision of the sensor for several of wastewater online monitoring.

Keywords: non-adiabatic fiber sensor, environmental sensing, biodegradability, evanescent field

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Authors: M. S. Lu, Y. P. Tsai, H. Shu, K. F. Chen, L. L. Lai

Abstract:

This study used sodium hypochlorite/sodium dodecyl sulfate method to successfully extract polyhydroxyalkanoates (PHA) from the wasted sludge of a husbandry industry wastewater treatment plant. We investigated the optimum operational conditions of three key factors with respect to effectively extract PHAs from husbandry industry wastewater sludge, including the sodium hypochlorite concentration, liquid-solid ratio, and reaction time. The experimental results showed the optimum operational conditions for polyhydroxyalkanoate recovery as follows: (1) being digested by the sodium hypochlorite/sodium dodecyl sulfate solution with 15% (v/v) of hypochlorite concentration, (2) being operated at the condition of 1.25 mLmg-1 of liquid-solid ratio, and (3) being reacted for more than 60 min. Under these conditions, the content of the recovered PHAs was about 53.2±0.66 mgPHAs/gVSS, and the purity of the recovered PHAs was about 78.5±6.91 wt%. The recovered PHAs were further used to produce biodegradable plastics for decomposition test buried in soils. The decomposition test showed 66.5% of the biodegradable plastics produced in the study remained after being buried in soils for 49 days. The cost for extracting PHAs is about 10.3 US$/kgPHAs and is lower than those produced by pure culture methods (12-15 US$/kgPHAs).

Keywords: biodegradable plastic, biopolymers, polyhydroxyalkanoates (PHAs), waste sludge

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Authors: Md Y. Reja, Samuel D. Brody, Wesley E. Highfield, Galen D. Newman

Abstract:

Historically, wetlands in the United States have been lost due to agriculture, anthropogenic activities, and rapid urbanization along the coast. Such losses of wetlands have resulted in high flooding risk for coastal communities over the period of time. In addition, alteration of wetlands via the Section 404 Clean Water Act permits can increase the flooding risk to future hurricane events, as the cumulative impact of this program is poorly understood and under-accounted. Further, recovery after hurricane events is acting as an encouragement for new development and reconstruction activities by converting wetlands under the wetland alteration permitting program. This study investigates the degree to which hurricane recovery activities in coastal communities are undermining the ability of these places to absorb the impacts of future storm events. Specifically, this work explores how and to what extent wetlands are being affected by the federal permitting program post-Hurricane Ike in 2008. Wetland alteration patterns are examined across three counties (Harris, Galveston, and Chambers County) along the Texas Gulf Coast over a 10-year time period, from 2004-2013 (five years before and after Hurricane Ike) by conducting descriptive spatial analyses. Results indicate that after Hurricane Ike, the number of permits substantially increased in Harris and Chambers County. The vast majority of individual and nationwide type permits were issued within the 100-year floodplain, storm surge zones, and areas damaged by Ike flooding, suggesting that recovery after the hurricane is compromising the ecological resiliency on which coastal communities depend. The authors expect that the findings of this study can increase awareness to policy makers and hazard mitigation planners regarding how to manage wetlands during a long-term recovery process to maintain their natural functions for future flood mitigation.

Keywords: ecological resiliency, Hurricane Ike, recovery, Section 404 Permitting, wetland alteration

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Authors: Mohamed Hassan, Rahul Gajbhiye

Abstract:

The high mobility and gravity override of CO₂ gas can be minimized by generating the CO₂ foam with the aid of surfactant. However, CO₂ is unable to generate the foam/stable foam above its supercritical point (1100 psi, 31°C). These difficulties with CO₂ foam is overcome by adding N₂ in small fraction to enhance the foam generation of CO₂ at supercritical conditions. This study shows how the addition of small quantity of N₂ helps in generating the CO₂ foam and performance of the CO₂/N₂ mixture foam in enhanced oil recovery. To investigate the performance of CO₂/N₂ foam, core-flooding experiments were conducted at elevated pressure and temperature condition (higher than supercritical CO₂ - 50°C and 1500 psi) in sandstone cores. Fluorosurfactant (FS-51) was used as a foaming agent, and n-decane was used as model oil in all the experiments. The selection of foam quality and N₂ fraction was optimized based on foam generation and stability tests. Every gas or foam flooding was preceded by seawater injection to simulate the behavior in the reservoir. The results from the core-flood experiments showed that the CO₂ and CO₂/N₂ foam flooding recovered an additional 34-40% of Original Initial Oil in Place (OIIP) indicating that foam flooding succeeded in producing more oil than pure CO₂ gas injection processes. Additionally, the performance CO₂/N₂ foam injection was better than CO₂ foam injection.

Keywords: CO₂/N₂ foam, enhanced oil recovery (EOR), supercritical CO₂, sweep efficiency

Procedia PDF Downloads 276

Authors: Tamas Bezsenyi, Noemi Katona

Abstract:

Fighting Human Trafficking is a highly important issue worldwide that states need to deal with in international politics. In the EU combatting human trafficking is emphasized in international policy making and also in the work of international law enforcement, thus in the work of the EUROPOL. While the EU Directive against Human Trafficking prescribes how states should fight this transnational crime and also how victims should be assisted, the EUROPOL focuses on the effective cooperation between national law enforcement agencies. However, despite the aims of the common fight, human trafficking is regulated differently in the punitive law of various nation states. This deeply defines the work and possibilities of national law enforcement organizations. Among the manifold differences in this paper, we focus on the role of regulating asset recovery. We highlight that money, and the regulation and practice how the law enforcement deals with income gained from criminal activities, play essential role in combatting human trafficking. While doing research on the investigation of transnational human trafficking by the Hungarian Law Enforcement Agencies, we have found that the unfortunate regulation of asset recovery determines the lower effectiveness of eliminating criminal organizations. While i.e. in the Netherlands confiscation of property takes place in an early stage of the criminal procedure, in Hungary it can be conducted only if money laundering is also assumed. Our presentation builds on the comparison of criminal procedures which we analyse based on criminal files and interviews with coworkers of the National Bureau of Investigation.

Keywords: human trafficking, law enforcement, asset recovery, organized crime

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Authors: Fan Wei, Tang Yipeng

Abstract:

The outbreak of COVID-19 in early 2020 has been raging around the world, which has severely affected people's work and life. In today's post-pandemic era, although the pandemic has been effectively controlled, people still need to maintain social distancing at all times to prevent the further spread of the virus. Based on this, social distancing in the context of the pandemic has aroused widespread attention from scholars. At present, most studies exploring the influencing factors of social distancing are studying the negative impact of social distancing on the physical and mental state of special groups from the inter-individual level, and their more focus on the forced complete social distancing during the severe period of the pandemic. Few studies have focused on the impact of social distancing on working groups in the post-pandemic era from the within-individual level. In order to explore this problem, this paper constructs a cross-level moderating model based on resource conservation theory from the perspective of psychological resources. A total of 81 subjects were recruited to fill in the three-stage questionnaires each day for 10 working days, and 661valid questionnaires were finally obtained. Through the empirical tests, the following conclusions were finally obtained: (1) At the within-individual level, daily social distancing is positively correlated with the second day’s recovery, and the individual’s low sociability regulates the relationship between social distancing and recovery. The indirect effect of daily social distancing through recovery has positive relationship employees’ work engagement and work-goal progress only when the individual has low sociability. For individuals with high sociability, none of these paths are significant. (2) At the within-individual level, there is a significant relationship between individual's recovery and work engagement and work-goal progress, indicating that the recovery of resources can produce positive work outcomes. According to the results, this study believes that in the post-pandemic era, social distancing can not only effectively prevent and control the pandemic but also have positive impacts. Employees can use the time and energy originally saved for social activities through social distancing to invest in things that can provide resources and help them recover.

Keywords: social distancing, recovery, work engagement, work goal progress, sociability

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Authors: Godwin Chigozie Okpara, Eugene Iheanacho

Abstract:

This paper examined the dynamic behavior of stock market development and the growth of Nigerian economy. The variables; market capitalization ratio, turnover ratio and liquidity proxies by the ratio of market capitalization to gross domestic product were sourced and computed from the Nigerian stock exchange fact books and the CBN statistical bulletin of the Central Bank of Nigeria. The variables were tested and found stationary and cointregrated using the augumented Dickey Fuller unit root test and the Johnson cointegration test respectively. The dynamic behavior of the stock market development model was verified using the error correction model. The result shows that about 0.4l percent of the short run deviation is corrected every year and also reveals that market capitalization ratio and market liquidity are positive and significant function of economic growth. In other words market capitalization ratio and liquidity positively and significantly impact economic growth. Market development variables such as turnover ratio and market restriction can exert positive but insignificant impact on the growth of the economy suggesting that securities transaction relative to the size of the securities market are not high enough to significantly engender economic growth in Nigeria. In the light of this, the researchers recommend that the regulatory body as well as the government, should provide a conducive environment capable of encouraging the growth and development of the stock market. This if well articulated will enhance the market turnover and the growth of the economy.

Keywords: market capitalization ratio, turnover ratio, liquidity, unit root test, cointegration

Procedia PDF Downloads 339