Search results for: low salt water injection

Authors: Yasufumi Yoshimoto, Enkhjargal Tserenochir, Eiji Kinoshita, Takeshi Otaka

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Next generation bio-alcohols produced from non-food based sources like cellulosic biomass are promising renewable energy sources. The present study investigates engine performance, combustion characteristics, and emissions of a small single cylinder direct injection diesel engine fueled by four kinds of next generation bio-alcohol isomer and diesel fuel blends with a constant blending ratio of 3:7 (mass). The tested bio-alcohol isomers here are n-butanol and iso-butanol (C₄ alcohol), and n-pentanol and iso-pentanol (C₅ alcohol). To obtain simultaneous reductions in NOx and smoke emissions, the experiments employed supercharging combined with EGR (Exhaust Gas Recirculation). The boost pressures were fixed at two conditions, 100 kPa (naturally aspirated operation) and 120 kPa (supercharged operation) provided with a roots blower type supercharger. The EGR rates were varied from 0 to 25% using a cooled EGR technique. The results showed that both with and without supercharging, all the bio-alcohol blended diesel fuels improved the trade-off relation between NOx and smoke emissions at all EGR rates while maintaining good engine performance, when compared with diesel fuel operation. It was also found that regardless of boost pressure and EGR rate, the ignition delays of the tested bio-alcohol isomer blends are in the order of iso-butanol > n-butanol > iso-pentanol > n-pentanol. Overall, it was concluded that, except for the changes in the ignition delays the influence of bio-alcohol isomer blends on the engine performance, combustion characteristics, and emissions are relatively small.

Keywords: alternative fuel, butanol, diesel engine, EGR (Exhaust Gas Recirculation), next generation bio-alcohol isomer blended fuel, pentanol, supercharging

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Authors: Selvan Bellan, Koji Matsubara, Nobuyuki Gokon, Tatsuya Kodama, Hyun Seok-Cho

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In concentrated solar thermal industry, fluidized-bed technology has been used to produce hydrogen by thermochemical two step water splitting cycles, and synthetic gas by gasification of coal coke. Recently, couple of fluidized bed reactors have been developed and tested at Niigata University, Japan, for two-step thermochemical water splitting cycles and coal coke gasification using Xe light, solar simulator. The hydrodynamic behavior of the gas-solid flow plays a vital role in the aforementioned fluidized bed reactors. Thus, in order to study the dynamics of dense gas-solid flow, a CFD-DEM model has been developed; in which the contact forces between the particles have been calculated by the spring-dashpot model, based on the soft-sphere method. Heat transfer and hydrodynamics of a solar thermochemical fluidized bed reactor filled with ceria particles have been studied numerically and experimentally for beam-down solar concentrating system. An experimental visualization of particles circulation pattern and mixing of two-tower fluidized bed system has been presented. Simulation results have been compared with experimental data to validate the CFD-DEM model. Results indicate that the model can predict the particle-fluid flow of the two-tower fluidized bed reactor. Using this model, the key operating parameters can be optimized.

Keywords: solar reactor, CFD-DEM modeling, fluidized bed, beam-down solar concentrating system

Procedia PDF Downloads 182

Authors: Ji Won Kim, Moo Yeol Lee, Keon Wook Kang

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GV-1001, 16 amino acid fragment of human telomerase reverse transcriptase catalytic subunit (hTERT), has been developed as an injectable cancer vaccine for many types of solid tumors showing high-level of telomerase activity. In the present study, we evaluated the anti-cancer effect of GV-1001 on androgen-receptor-positive prostate cancer. Two signaling pathways, Gs-adenylate cyclase-cAMP and Gq-IP3-Ca2+ pathways play a central role in GnRH receptor (GnRHR)-mediated activities. We found that leuprolide acetate (LA) mainly acted on Gq-mediated Ca2+ signaling, while GV-1001 preferentially acted on cAMP signaling; and both the effects were counteracted by cetrorelix, a GnRHR antagonist. We further tested whether GV-1001 affects tumor growth of human prostate cancer cells in vivo. Prostate tumor xenografts were established using LNCap, androgen receptor-positive prostate cancer cells, and the nude mice bearing tumors were subcutaneously injected with GV-1001 (0.01, 0.1, 1, 10 microg/kg/day) and LA (0.01 microg/kg/day) for 2 weeks. GV-1001 (1 and 10 microg/kg/day) significantly inhibited tumor growth of LNCap xenografts. Interestingly, mRNA expression of MMP2 and MMP9 was significantly suppressed by GV-1001 injection, but not by LA administration. Boyden chamber assay revealed that GV-1001 potently inhibited cell migration of LNCap. Our finding suggests that GV-1001 as a novel GnRHR ligand, has anti-proliferative and anti-migratory effects on androgen receptor-positive prostate cancer cells.

Keywords: GV-1001, GnRH, hTERT, prostate cancer

Procedia PDF Downloads 349

Authors: Sundaram Chandrasekaran, Seung Hyun Hur

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Exploring strategies for oxygen vacancy engineering under mild conditions and understanding the relationship between dislocations and photoelectrochemical (PEC) cell performance are challenging issues for designing high performance PEC devices. Therefore, it is very important to understand that how the oxygen vacancies (VO) or other defect states affect the performance of the photocatalyst in photoelectric transfer. So far, it has been found that defects in nano or micro crystals can have two possible significances on the PEC performance. Firstly, an electron-hole pair produced at the interface of photoelectrode and electrolyte can recombine at the defect centers under illumination of light, thereby reducing the PEC performances. On the other hand, the defects could lead to a higher light absorption in the longer wavelength region and may act as energy centers for the water splitting reaction that can improve the PEC performances. Even if the dislocation growth of ZnO has been verified by the full density functional theory (DFT) calculations and local density approximation calculations (LDA), it requires further studies to correlate the structures of ZnO and PEC performances. Exploring the hybrid structures composed of graphene oxide (GO) and ZnO nanostructures offer not only the vision of how the complex structure form from a simple starting materials but also the tools to improve PEC performances by understanding the underlying mechanisms of mutual interactions. As there are few studies for the ZnO growth with other materials and the growth mechanism in those cases has not been clearly explored yet, it is very important to understand the fundamental growth process of nanomaterials with the specific materials, so that rational and controllable syntheses of efficient ZnO-based hybrid materials can be designed to prepare nanostructures that can exhibit significant PEC performances. Herein, we fabricated various ZnO nanostructures such as hollow sphere, bucky bowl, nanorod and triangle, investigated their pH dependent growth mechanism, and correlated the PEC performances with them. Especially, the origin of well-controlled dislocation-driven growth and its transformation mechanism of ZnO nanorods to triangles on the GO surface were discussed in detail. Surprisingly, the addition of GO during the synthesis process not only tunes the morphology of ZnO nanocrystals and also creates more oxygen vacancies (oxygen defects) in the lattice of ZnO, which obviously suggest that the oxygen vacancies be created by the redox reaction between GO and ZnO in which the surface oxygen is extracted from the surface of ZnO by the functional groups of GO. On the basis of our experimental and theoretical analysis, the detailed mechanism for the formation of specific structural shapes and oxygen vacancies via dislocation, and its impact in PEC performances are explored. In water splitting performance, the maximum photocurrent density of GO-ZnO triangles was 1.517mA/cm-2 (under UV light ~ 360 nm) vs. RHE with high incident photon to current conversion Efficiency (IPCE) of 10.41%, which is the highest among all samples fabricated in this study and also one of the highest IPCE reported so far obtained from GO-ZnO triangular shaped photocatalyst.

Keywords: dislocation driven growth, zinc oxide, graphene oxide, water splitting

Procedia PDF Downloads 276

Authors: Mathew O. Ayoola, Foluke Aderemi, Tunde E. Lawal, Opeyemi Oladejo, Micheal A. Abiola

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Food animals reared for meat require transportation during their life cycle. The transportation procedures could initiate stressors capable of disrupting the physiological homeostasis. Such stressors associated with transportation may include; loading and unloading, crowding, environmental temperature, fear, vehicle motion/vibration, feed / water deprivation, and length of travel. This may cause oxidative stress and damage to excess free radicals or reactive oxygen species (ROS). In recent years, the application of natural products as a substitute for synthetic electrolytes and tranquilizers as anti-stress agents during the transportation is yet under investigation. Sweet orange, a predominant fruit in humid tropics, has been reported to have a good content of vitamin C (Ascorbic acid). Vitamin C, which is an active ingredient in orange juice, plays a major role in the biosynthesis of Corticosterone, a hormone that enhances energy supply during transportation and heat stress. Ninety-six, 15weeks, Isa brown pullets were allotted to four (4) oral treatments; sterile water (T1), synthetic vit C (T2), 30ml orange/liter of water (T3), 50ml orange/1 liter (T4). Physiological parameters; body temperature (BTC), rectal temperature (RTC), respiratory rate (RR), and panting rate (PR) were measured pre and post-transportation. The birds were transported with a specialized vehicle for a distance of 50km at a speed of 60 km/hr. The average environmental THI and within the vehicle was 81.8 and 74.6, respectively, and the average wind speed was 11km/hr. Treatments and periods had a significant (p>0.05) effect on all the physiological parameters investigated. Birds on T1 are significantly (p<0.05) different as compared to T2, T3, and T4. Values recorded post-transportation are significantly (p<0.05) higher as compared to pre-transportation for all parameters. In conclusion, this study showed that transportation as a stressor can affect the physiological homeostasis of pullets. Oral supplementation of electrolytes or tranquilizers is essential as an anti-stress during transportation. The application of the organic product in form of sweet orange could serve as a suitable alternative for the synthetic vitamin C.

Keywords: physiological, pullets, sweet orange, transportation stress, and vitamin C

Procedia PDF Downloads 104

Authors: Yao Xing, Hong Ling Liu, Wei Dong Yu

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With the increase of global population, it is of importance for the safe water supply, while, the water-monitoring method with the capability of rapidness, low-cost, green and robustness remains unsolved. In this paper, gold nanoclusters-wool keratin is added into copper ions measured by fluorescent method in order to probe copper ions in aqueous solution. The fluorescent results show that gold nanoclusters-wool keratin exhibits high stability of pHs, while it is sensitive to temperature and time. Based on Gauss fitting method, the results exhibit that the slope of gold nanoclusters-wool keratin with pH resolution under acidic condition is higher compared to it under alkaline solutions. Besides, gold nanoclusters-wool keratin added into copper ions shows a fluorescence turn-off response transferring from red to blue under UV light, leading to the dramatically decreased fluorescent intensity of gold nanoclusters-wool keratin solution located at 690 nm. Moreover, the limited concentration of copper ions tested by gold nanoclusters-wool keratin system is around 1 µmol/L, which meets the need of detection standards. The fitting slope of Stern-Volmer plot at low concentration of copper ions is larger than it at high concentrations, which indicates that aggregated gold nanoclusters are from small amounts to large numbers with the increasing concentration of copper ions. It is expected to provide novel method and materials for copper ions testing with low cost, high efficiency, and easy operability.

Keywords: gold nanoclusters, copper ions, wool keratin, fluorescence

Procedia PDF Downloads 235

Authors: Anjali G. Pillai, S. Chadrakaran

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The extensive amount of sludge generated throughout the world, as a part of water treatment works, have caused various social and economic issues, such as a demand on landfill spaces, increase in environmental pollution and raising the waste management cost. With growing social awareness about toxic incinerator emissions and the increasing concern over the disposal of sludge on the agricultural land, the recovery of sewage sludge as a building and construction raw material can be considered as an innovative approach to tackle the sludge disposal problem. The proposed work aims at studying the recycling ability of the sludge, generated from the water treatment process, by incorporating it into the fired clay brick units. The work involves initial study of the geotechnical characteristics of the brick-clay and the sludge. Chemical compatibility of both the materials will be analyzed by X-ray fluorescence technique. The variation in the strength aspects with varying proportions of sludge i.e. 10%, 20%, 30% and 40% in the sludge-clay mix will also be determined by the proctor density test. Based on the optimum moisture content, the sludge-clay bricks will be manufactured in a brick manufacturing plant and the modified brick units will be tested to determine the variation in compressive strength, bulk density, firing shrinkage, shrinkage loss and initial water absorption rate with respect to the conventional clay bricks. The results will be compared with the specifications given in Indian Standards to arrive at the potential use of the new bricks. The durability aspect will be studied by conducting the leachate analysis test using atomic adsorption spectrometry. The lightweight characteristics of the sludge modified bricks will be ascertained with the scanning electron microscope technique which will be indicative of the variation in pore structure with the increase in sludge content within the bricks. The work will determine the suitable proportion of the sludge – clay mix in the brick which can then be effectively implemented. The feasibility aspect of the work will be determined for commercial production of the units. The work involves providing a strategy for conversion of waste to resource. Moreover, it provides an alternative solution to the problem of growing scarcity of brick-clay for the manufacturing of fired clay bricks.

Keywords: eco-bricks, green construction material, sludge amended bricks, sludge disposal, waste management

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Authors: K. R. Sultana, K. Pope, Y. S. Muzychka

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In recent years, the research of heat transfer or phase change phenomena of liquid water droplets experiences a growing interest in aircraft icing, power transmission line icing, marine icing and wind turbine icing applications. This growing interest speeding up the research from single to multiple droplet phenomena. Impingements of multiple droplets and the resulting solidification phenomena after impact on a very cold surface is computationally studied in this paper. The model used in the current study solves the flow equation, composed of energy balance and the volume fraction equations. The main aim of the study is to investigate the effects of several thermo-physical properties (density, thermal conductivity and specific heat) on droplets freezing. The outcome is examined by various important factors, for instance, liquid fraction, total freezing time, droplet temperature and total heat transfer rate in the interface region. The liquid fraction helps to understand the complete phase change phenomena during solidification. Temperature distribution and heat transfer rate help to demonstrate the overall thermal exchange behaviors between the droplets and substrate surface. Findings of this research provide an important technical achievement for ice modeling and prediction studies.

Keywords: droplets, CFD, thermos-physical properties, solidification

Procedia PDF Downloads 229

Authors: Rotimi Larayetana, Yahaya Abdulrazaq, Oladunni O. Falola, Abayomi Ajayi

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The aim of this study was to perform green synthesis of silver nanoparticles (AgNPs) with the aqueous extract of Moringa oleifera Lam (M oleifera) leaves and determine its effects on benign prostatic hyperplasia in Wistar rats. Silver nitrate (AgNO₃) solution was reduced using the aqueous extract of Moringa oleifera Lam leaves, the resultant biogenic AgNPs were characterized by Fourier transformed infrared spectrophotometric, SEM, TEM and X-ray diffraction analysis. Animal experiments involved thirty (30) adult male Wistar rats randomly divided into five groups (A to E; n ₌ 5). Group A received only subcutaneous injection of olive oil daily while the other groups got 3 mg/kg/daily of testosterone propionate (TP) subcutaneously plus 50 mg/kg/daily of AgNPs intraperitoneally (B), 3 mg/kg/daily of TP plus 25 mg/kg/daily of AgNPs (C), 3 mg/kg/daily of TP only (D) and 25 mg/kg/daily of AgNPs only (E). The animals were sacrificed after 14 days, and the prostate gland, liver, and kidney were processed for histological analysis. Phytochemical screening and GC-MS analysis were performed to determine the composition of the M oleifera extract used. Biogenic AgNPs with an average diameter of 23 nm were synthesized. Biogenic AgNPs ameliorated hormone-induced prostate enlargement, and the inhibition of prostatic hypertrophy could be due to the presence of a significant amount of plant fatty acids and phytosterols in the aqueous extract of M oleifera extract. However, the administration of biogenic AgNPs at higher doses impacted negatively on the cytoarchitecture of the liver. Green synthesis of AgNPs with the aqueous extract of Moringa oleifera might be beneficial for the treatment of BPH.

Keywords: benign prostatic hyperplasia, biogenic synthesis, Moringa oleifera, silver nanoparticles, testosterone

Procedia PDF Downloads 72

Authors: Mairaj Ahmad, L. Paglia, F. Marra, V. Genova, G. Pulci

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This study employed Rene N4 and FSX 414 superalloys, which are used in numerous turbine engine components due of their high strength, outstanding fatigue, creep, thermal, and corrosion-resistant properties. An in-depth examination of corrosion mechanisms with vapor present at high temperature is necessary given the industrial trend toward introducing increasing amounts of hydrogen into combustion chambers in order to boost power generation and minimize pollution in contrast to conventional fuels. These superalloys were oxidized in recent tests for 500, 1000, 2000, 3000 and 4000 hours at 982±5°C temperatures with a steady airflow at a flow rate of 10L/min and 1.5 bar pressure. These superalloys were also examined for wet corrosion for 500, 1000, 2000, 3000, and 4000 hours in a combination of air and water vapor flowing at a 10L/min rate. Weight gain, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive x-ray spectroscopy (EDS) were used to assess the oxidation and heat corrosion resistance capabilities of these alloys before and after 500, 1000, and 2000 hours. The oxidation/corrosion processes that accompany the formation of these oxide scales are shown in the graph of mass gain vs time. In both dry and wet oxidation, oxides like Al2O3, TiO2, NiCo2O4, Ni3Al, Ni3Ti, Cr2O3, MnCr2O4, CoCr2O4, and certain volatile compounds notably CrO2(OH)2, Cr(OH)3, Fe(OH)2, and Si(OH)4 are formed.

Keywords: hot corrosion, oxidation, turbine materials, high temperature corrosion, super alloys

Procedia PDF Downloads 69

Authors: S. A. Agbalajobi, W. A. Bello

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This study examines rock properties of crushed aggregate in some selected quarries in Kwara state, Nigeria. Some physical properties (chemical composition, mineral composition, particle size distribution) of gneiss sample were determined using ISRM standards. The physicomechanical properties (specific gravity, dry density, porosity, water absorption, point load index, tensile, and compressive strength) of the gneiss rock were evaluated. The analysis on the gneiss samples revealed the mean dry density and the unit weight are 2.52 g/m3, 2.63 g/m3, 2.38 g/m3; and 24.1 kN/m3, 25.78 kN/m3, 23.33 kN/m3, respectively (for locations A,B,C). The water absorption level of the gneiss rock sample ranged from 0.38 % – 0.57 % for the three locations. The mean Schmidt hammer rebound value ranged from 51.0 – 52.4 for the three locations and mean point load index values ranged from 9.89 – 10.56 MPa classified as very high strength while the uniaxial compressive strength of the rock samples revealed that its strength ranged from 120 - 139 MPa (for location A, B, and C) classified as strong rock. The aggregate impact value test and aggregate crushing value test conducted on the gneiss aggregates from the three locations in accordance with British Standard. The gneiss sample from the three locations (A, B, and C) is a good material for the production of construction works such as concrete, bricks, pavement, embankment among others, the compressive strength of the material is within the accepted limit.

Keywords: gneiss, aggregate impact, aggregate crushing, physic-mechanical properties, rock hardness

Procedia PDF Downloads 293

Authors: Jun Yang, Ching-Liang Hsieh, Yi-Wen Lin

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Chronic inflammatory pain results from peripheral tissue injury or local inflammation to increase the release of protons, histamines, adenosine triphosphate, and several proinflammatory cytokines. Transient receptor potential vanilloid 1 (TRPV1) is involved in fibromyalgia, neuropathic, and inflammatory pain; however, its exact mechanisms in chronic inflammatory pain are still unclear. We investigate the analgesic effect of EA by injecting complete Freund’s adjuvant (CFA) in the hind paw of mice to induce chronic inflammatory pain ( > 14 d). Our results showed that EA significantly reduced chronic mechanical and thermal hyperalgesia in the chronic inflammatory pain model. Chronic mechanical and thermal hyperalgesia was also abolished in TRPV1−/− mice. TRPV1 increased in the dorsal root ganglion (DRG) and spinal cord (SC) at 2 weeks after CFA injection. The expression levels of downstream molecules such as pPKA, pPI3K, and pPKC increased, as did those of pERK, pp38, and pJNK. Transcription factors (pCREB and pNFκB) and nociceptive ion channels (Nav1.7 and Nav1.8) were involved in this process. Inflammatory mediators such as GFAP (Glial fibrillary acidic protein), S100B, and RAGE (Receptor for advanced glycation endproducts) were also involved. The expression levels of these molecules were reduced in EA (electroacupuncture) and TRPV1−/−mice but not in the sham EA group. The present study demonstrated that EA or TRPV1 gene deletion reduced chronic inflammatory pain through TRPV1 and related molecules. In addition, our data provided evidence to support the clinical use of EA for treating chronic inflammatory pain.

Keywords: auricular electric-stimulation, epileptic seizures, anti-inflammation, electroacupuncture

Procedia PDF Downloads 159

Authors: Helena Dvořáčková, Jakub Elbl, Irina Mikajlo, Antonín Kintl, Jaroslav Hynšt, Olga Urbánková, Jaroslav Záhora

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Application of biochar to arable soils represents a new approach to restore soil health and quality. Many studies reported the positive effect of biochar application on soil fertility and development of soil microbial community. Moreover biochar may affect the soil water retention, but this effect has not been sufficiently described yet. Therefore this study deals with the influence of biochar application on: microbial activities in soil, availability of mineral nitrogen in soil for microorganisms, mineral nitrogen retention and plant production. To demonstrate the effect of biochar addition on the above parameters, the pot experiment was realized. As a model crop, Lactuca sativa L. was used and cultivated from December 10th 2014 till March 22th 2015 in climate chamber in thoroughly homogenized arable soil with and without addition of biochar. Five variants of experiment (V1–V5) with different regime of irrigation were prepared. Variants V1–V2 were fertilized by mineral nitrogen, V3–V4 by biochar and V5 was a control. The significant differences were found only in plant production and mineral nitrogen retention. The highest content of mineral nitrogen in soil was detected in V1 and V2, about 250 % in comparison with the other variants. The positive effect of biochar application on soil fertility, mineral nitrogen availability was not found. On the other hand results of plant production indicate the possible positive effect of biochar application on soil water retention.

Keywords: arable soil, biochar, drought, mineral nitrogen

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Authors: Tawfiq Chekifi, Brahim Dennai, Rachid Khelfaoui

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Over the last few decades, modeling immiscible fluids such as oil and water have been a classical research topic. Droplet-based microfluidics presents a unique platform for mixing, reaction, separation, dispersion of drops, and numerous other functions. For this purpose, several devices were studied, as well as microfluidic oscillator. The latter was obtained from wall attachment microfluidic amplifiers using a feedback loop from the outputs to the control inputs, nevertheless this device have not well used for microdrops applications. In this paper, we suggest a numerical CFD study of a microfluidic oscillator with two different lengths of feedback loop. In order to produce simultaneous microdrops of gasoil on water, a typical geometry that includes double T-junction is connected to the fluidic oscillator. The generation of microdrops is computed by volume-of-fluid method (VOF). Flow oscillations of microdrops were triggered by the Coanda effect of jet flow. The aim of work is to obtain a high oscillation frequency in output of this passive device, the influence of hydrodynamics and physics parameters on the microdrops frequency in the output of our microsystem is also analyzed, The computational results show that, the length of feedback loop, applied pressure on T-junction and interfacial tension have a significant effect on the dispersion of microdrops and its oscillation frequency. Across the range of low Reynold number, the microdrops generation and its dynamics have been accurately controlled by adjusting applying pressure ratio of two phases.

Keywords: fluidic oscillator, microdrops manipulation, VOF (volume of fluid method), microfluidic oscillator

Procedia PDF Downloads 373

Authors: Kiurski S. Jelena, Kecić S. Vesna, Aksentijević M. Snežana

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Samples of tap and wastewater were collected in three offset printing facilities in Novi Sad, Serbia. Ten physicochemical parameters were analyzed within all collected samples: pH, conductivity, m - alkalinity, p - alkalinity, acidity, carbonate concentration, hydrogen carbonate concentration, active oxygen content, chloride concentration and total alkali content. All measurements were conducted using the standard analytical and instrumental methods. Comparing the obtained results for tap water and wastewater, a clear quality difference was noticeable, since all physicochemical parameters were significantly higher within wastewater samples. The study also involves the application of simple linear regression analysis on the obtained dataset. By using software package ORIGIN 5 the pH value was mutually correlated with other physicochemical parameters. Based on the obtained values of Pearson coefficient of determination a strong positive correlation between chloride concentration and pH (r = -0.943), as well as between acidity and pH (r = -0.855) was determined. In addition, statistically significant difference was obtained only between acidity and chloride concentration with pH values, since the values of parameter F (247.634 and 182.536) were higher than F_critical (5.59). In this way, results of statistical analysis highlighted the most influential parameter of water contamination in offset printing, in the form of acidity and chloride concentration. The results showed that variable dependence could be represented by the general regression model: y = a₀ + a₁x+ k, which further resulted with matching graphic regressions.

Keywords: pollution, printing industry, simple linear regression analysis, wastewater

Procedia PDF Downloads 221

Authors: S. Ataei, F. Sarrafzadeh Javadi, K. Gilani, E. Moazeni

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Drug delivery systems using colloidal particulate carriers such as niosomes or liposomes have distinct advantages over conventional dosage forms because the particles can act as drug-containing reservoirs. These carriers play an increasingly important role in drug delivery. Niosomes are vesicular delivery systems which result from the self-assembly of hydrated surfactant. Niosomes are now widely studied as an attractive to liposomes because they alleviate the disadvantages associated with liposomes, such as chemical instability, variable purity of phospholipids and high cost. The encapsulation of drugs in niosomes can decrease drug toxicity, increase the stability of drug and increase the penetrability of drug in the location of application, and may reduce the dose and systemic side effect. Nowadays, Niosomes are used by the pharmaceutical industry in manufacturing skin medications, eye medication, in cosmetic formulas and these vesicular systems can be used to deliver aspiratory drugs. One way of improving dispersion in the water phase and solubility of the hydrophobic drug is to formulate in into niosomes. Itraconazole (ITZ) was chosen as a model hydrophobic drug. This drug is water insoluble (solubility ~ 1 ng/ml at neutral pH), is a broad-spectrum triazole antifungal agent and is used to treat various fungal disease. This study aims to investigate the capability of forming itraconazole niosomes with Spans, Tweens, Brijs as non-ionic surfactants. To this end, various formulations of niosomes have been studied with regard to parameters such as the degree of containment and particle size.

Keywords: physicochemical, non-ionic surfactant vesicles, itraconazole

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Authors: Duong Cong Chinh, Shiao-Shing Chen, Le Quang Huy

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Membrane distillation (MD) is actually claimed to be a cost-effective separation process when waste heat, alternative energy sources, or wastewater are used. To the best of our knowledge, this is the first study that a thermophilic anaerobic granular bioreactor is integrated with membrane distillation (ThAnMDB) was investigated. In this study, the laboratory scale anaerobic bioreactor (1.2 litter) was set-up. The bioreactor was maintained at temperature 55 ± 2°C, hydraulic retention time = 0.5 days, organic loading rates of 7 and 10 kg chemical oxygen demand (COD) m³/day. Side-stream direct contact membrane distillation with the polytetrafluoroethylene membrane area was 150 cm². The temperature of the distillate was kept at 25°C. Results show that distillate flux was 19.6 LMH (Liters per square meter per hour) on the first day and gradually decreased to 6.9 LMH after 10 days, and the membrane was not wet. Notably, by directly using the heat from the thermophilic anaerobic for MD separation process, all distilled water from wastewater was reuse as fresh water (electrical conductivity < 120 µs/cm). The ThAnMDB system showed its high pollutant removal performance: chemical oxygen demand (COD) from 99.6 to 99.9%, NH₄⁺ from 60 to 95%, and PO₄³⁻ complete removal. In addition, methane yield was from 0.28 to 0.34 lit CH₄/gram COD removal (80 – 97% of the theoretical) demonstrated that the ThAnMDB system was quite stable. The achievement of the ThAnMDB is not only in removing pollutants and reusing wastewater but also in absolutely unnecessarily adding alkaline to the anaerobic bioreactor system.

Keywords: high rate anaerobic digestion, membrane distillation, thermophilic anaerobic, wastewater reuse

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Authors: Iyiola Olusola Oluwaleye, Samson A. Adeleye, Omojola Awogbemi

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This paper reports an investigation of the comparative effects of drying on the quality of some leafy vegetables at three different temperatures namely: 50ᵒC, 60ᵒC and 70ᵒC. The vegetables investigated are spinach (Amaranthus cruentus); water leaf (Talinum triangulare); lettuce (Lactuca satuva); and fluted pumpkin (Telfaria occidentalis). These vegetables are available in abundance during raining season and are commonly consumed by average Nigerians. A convective dryer was used for the drying process at the stipulated temperatures which were maintained with the aid of a thermostat. The vegetable samples after washing was cut into smaller sizes of 0.4 cm-0.5 cm and loaded into the drying cage of the convective dryer. The daily duration of the drying is six hours from 9:00 am to 3:00 pm. The dried samples were thereafter subjected to microbial and proximate analyses. The result of the tests shows that the microbial load decreases as the drying temperature increases. As temperature increases, the moisture content and carbohydrate of all the samples decreases while the crude fiber, ash and protein increases. Percentage fat content decreases as drying temperature increases with the exception of fluted pumpkin. The shelf life of the vegetable samples increase with drying temperature, Spinach has the lowest shelf life followed by Fluted Pumpkin, followed by lettuce while Water Leaf has the highest shelf life at the three drying temperatures of 50ᵒC, 60ᵒC and 70ᵒC respectively.

Keywords: convective drying, leafy vegetables, quality, shelf life

Procedia PDF Downloads 247

Authors: Mohamed A. Etman, Mona G. Abd-Elnasser, Mohamed A. Shams-Eldin, Aly H. Nada

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Orally disintegrating tablets (ODTs) are gaining importance as new drug delivery systems and emerged as one of the popular and widely accepted dosage forms, especially for the pediatric and geriatric patients. Their advantages such as administration without water, anywhere, anytime lead to their suitability to geriatric and pediatric patients. They are also suitable for the mentally ill, the bed-ridden and patients who do not have easy access to water. The benefits, in terms of patient compliance, rapid onset of action, increased bioavailability, and good stability make these tablets popular as a dosage form of choice in the current market. These dosage forms dissolve or disintegrate in the oral cavity within a matter of seconds without the need of water or chewing. Desloratadine is a tricyclic antihistaminic, which has a selective and peripheral H1-antagonist action. It is an antagonist at histamine H1 receptors, and an antagonist at all subtypes of the muscarinic acetylcholine receptor. Desloratadine is the major metabolite of loratadine. Twelve different placebos ODT were prepared (F1-F12) using different functional excipients. They were evaluated for their compressibility, hardness and disintegration time. All formulations were non sticky except four formulations; namely (F8, F9, F10, F11). All formulations were compressible with the exception of (F2). Variable disintegration times were found ranging between 20 and 120 seconds. It was found that (F12) showed the least disintegration time (20 secs) without showing any sticking which could be due to the use of high percentage of superdisintegrants. Desloratadine showed bitter taste when formulated as ODT without any treatment. Therefore, different techniques were tried in order to mask its bitter taste. Using Eudragit EPO resulted in complete masking of the bitter taste of the drug and increased the acceptability to volunteers. The compressible non sticky formulations (F1, F3, F4, F5, F6, F7 and F12) were subjected to further evaluation tests after addition of coated desloratadine, including weight uniformity, wetting time, and friability testing.. Fairly good weight uniformity values were observed in all the tested formulations. F12 exhibiting the shortest wetting time (14.7 seconds) and consequently the lowest (20 seconds) disintegration time. Dissolution profile showed that 100% desloratadine release was attained after only 2.5 minutes from the prepared ODT (F12) with dissolution efficiency of 95%.

Keywords: Desloratadine, orally disintegrating tablets (ODTs), formulations, taste masking

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Authors: Zeineb Baatout, Safa Teka, Nejmeddine Jaballah, Nawfel Sakly, Xiaonan Sun, Mustapha Majdoub

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Currently, the economic interests linked to the development of bio-based materials make biomass one of the most interesting areas for science development. We are interested in the β-cyclodextrin (β-CD), one of the popular bio-sourced macromolecule, produced from the starch via enzymatic conversion. It is a cyclic oligosaccharide formed by the association of seven glucose units. It presents a rigid conical and amphiphilic structure with hydrophilic exterior, allowing it to be water-soluble. It has also a hydrophobic interior enabling the formation of inclusion complexes, which support its application for the elaboration of electrochemical and optical sensors. Nevertheless, the solubility of β-CD in water makes its use as sensitive layer limit and difficult due to their instability in aqueous media. To overcome this limitation, we chose to precede by modification of the hydroxyl groups to obtain hydrophobic derivatives which lead to water-stable sensing layers. Hence, a series of benzylated β-CDs were synthesized in basic aqueous media in one pot. This work reports the synthesis of a new family of substituted amphiphilic β-CDs using a green methodology. The obtained β-CDs showed different degree of substitution (DS) between 0.85 and 2.03. These organic macromolecular materials were soluble in common organic volatile solvents, and their structures were investigated by NMR, FT-IR and MALDI-TOF spectroscopies. Thermal analysis showed a correlation between the thermal properties of these derivatives and the benzylation degree. The surface properties of the thin films based on the benzylated β-CDs were characterized by contact angle measurements and atomic force microscopy (AFM). These organic materials were investigated as sensitive layers, deposited on quartz crystal microbalance (QCM) gravimetric transducer, for humidity sensor at room temperature. The results showed that the performances of the prepared sensors are greatly influenced by the benzylation degree of β-CD. The partially modified β-CD (DS=1) shows linear response with best sensitivity, good reproducibility, low hysteresis, fast response time (15s) and recovery time (17s) at higher relative humidity levels (RH) between 11% and 98% in room temperature.

Keywords: β-cyclodextrin, green synthesis, humidity sensor, quartz crystal microbalance

Procedia PDF Downloads 258

Authors: Saad M. Howladar, Mostafa M. Rady, Wael M. Semida

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A field experiment was conducted during the two successive seasons of 2012 and 2013 in the Experimental Farm (newly-reclaimed saline soil; EC = 7.8 dS m-1), Faculty of Agriculture, Fayoum University, Fayoum, Egypt to investigate the effect of vitamin C foliar application at the rates of 1, 2, 3 and 4 mM on the possibility of improving growth, seed and oil yields, and some chemical constituents of Helianthus annuus L. plants under the adverse conditions of the selected soil. Significant positive influences of all vitamin C treatments were observed on growth, seed and oil yields and some chemical constituents in both seasons. Compared to unsprayed plants (control), spraying plants with various rates of vitamin C significantly increased vegetative growth traits (i.e. plant height, No. of leaves plant-1, leaf area leaf-1, total leaves area plant-1, and dry weights of leaves and shoot plant-1) and seed and oil yields and their components (i.e. head diameter, seed weight head-1, 100-seed weight, seed yield feddan-1 and oil yield feddan-1). In addition, the concentrations of chlorophyll a, chlorophyll b, total chlorophylls, total carotenoids and total phenols in fresh leaves, and total carbohydrates, total soluble sugars, free proline and some nutrients (i.e. N, P, K, Fe, Mn, and Zn) in dry leaves were also increased significantly with all vitamin C applications. Vitamin C treatment at the rate of 3 mM was generated the best results. These results are important as the potential of vitamin C to alleviate the harmful effects of salt stress offer an opportunity to increase the resistance of sunflower plants to grow under saline conditions of the newly-reclaimed soils.

Keywords: sunflower, Helianthus annuus L., ascorbic acid, salinity, growth, seed yield, oil content, chemical composition

Procedia PDF Downloads 440

Authors: Hritik Bhattarai

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Land use and land cover play a crucial role in preserving and managing Earth's natural resources. Various factors, such as economic, demographic, social, cultural, technological, and environmental processes, contribute to changes in land use and land cover (LULC). Rupandehi District is significantly influenced by a combination of driving forces, including its geographical location, rapid population growth, economic opportunities, globalization, tourism activities, and political events. Urbanization and urban growth in the region have been occurring in an unplanned manner, with internal migration and natural population growth being the primary contributors. Internal migration, particularly from neighboring districts in the higher and lower Himalayan regions, has been high, leading to increased population growth and density. This study utilizes geospatial technology, specifically geographic information system (GIS), to analyze and illustrate the land cover and land use changes in the Rupandehi district for the years 2009 and 2019, using freely available Landsat images. The identified land cover categories include built-up area, cropland, Das-Gaja, forest, grassland, other woodland, riverbed, and water. The statistical analysis of the data over the 10-year period (2009-2019) reveals significant percentage changes in LULC. Notably, Das-Gaja shows a minimal change of 99.9%, while water and forest exhibit increases of 34.5% and 98.6%, respectively. Riverbed and built-up areas experience changes of 95.3% and 39.6%, respectively. Cropland and grassland, however, show concerning decreases of 102.6% and 140.0%, respectively. Other woodland also indicates a change of 50.6%. The most noteworthy trends are the substantial increase in water areas and built-up areas, leading to the degradation of agricultural and open spaces. This emphasizes the urgent need for effective urban planning activities to ensure the development of a sustainable city. While Das-Gaja seems unaffected, the decreasing trends in cropland and grassland, accompanied by the increasing built-up areas, are unsatisfactory. It is imperative for relevant authorities to be aware of these trends and implement proactive measures for sustainable urban development.

Keywords: land use and land cover, geospatial, urbanization, geographic information system, sustainable urban development

Procedia PDF Downloads 43

Authors: L. Al Ahmad, C. Latrille, D. Hainos, D. Blanc, M. Clausse

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A two-dimensional finite volume axisymmetric model is developed to predict the simultaneous heat and mass transfers during the drying of industrial sludge. The simulations were run using COMSOL-Multiphysics 3.5a. The input parameters of the numerical model were acquired from a preliminary experimental work. Results permit to establish correlations describing the evolution of the various parameters as a function of the drying temperature and the sludge water content. The selection and coupling of the equation are validated based on the drying kinetics acquired experimentally at a temperature range of 45-65 °C and absolute pressure range of 200-1000 mbar. The model, incorporating the heat and mass transfer mechanisms at different operating conditions, shows simulated values of temperature and water content. Simulated results are found concordant with the experimental values, only at the first and last drying stages where sludge shrinkage is insignificant. Simulated and experimental results show that sludge drying is favored at high temperatures and low pressure. As experimentally observed, the drying time is reduced by 68% for drying at 65 °C compared to 45 °C under 1 atm. At 65 °C, a 200-mbar absolute pressure vacuum leads to an additional reduction in drying time estimated by 61%. However, the drying rate is underestimated in the intermediate stage. This rate underestimation could be improved in the model by considering the shrinkage phenomena that occurs during sludge drying.

Keywords: industrial sludge drying, heat transfer, mass transfer, mathematical modelling

Procedia PDF Downloads 113

Authors: Hager Elsheikh, Matthias Sendler, Juliana Glaubnitz

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In pancreatitis, an inflammatory reaction occurs in the pancreatic secretory cells due to premature activation of proteases, leading to pancreatic self-digestion and necrotic cell death of acinar cells. Acute pancreatitis in patients is characterized by a severe immune reaction that could lead to serious complications, such as organ failure or septic shock, if left untreated. Chronic pancreatitis is a recurrence of episodes of acute pancreatitis resulting in a fibro-inflammatory immune response, in which the type 2 immune response is primarily driven by AAMs in the pancreas. One of the most important signaling pathways for M2 macrophage activation is the IL-4/STAT6 pathway. Pancreatic fibrosis is induced by the hyperactivation of pancreatic stellate cells by dysregulation in the inflammatory response, leading to further damage, autodigestion and possibly necrosis of pancreatic acinar cells. The aim of this research is to investigate the effect of STAT6 knockout in disease severity and development of fibrosis wound healing in the presence of different macrophage populations, regulated by the type 2 immune response, after inducing chronic and/or acute pancreatitis in mice models via cerulean injection. We further investigate the influence of the JAK/STAT6 signaling pathway on the balance of fibrosis and regeneration in STAT6 deficient and wild-type mice. The characterization of resident and recruited macrophages will provide insight into the influence of the JAK/STAT6 signaling pathway on infiltrating cells and, ultimately, tissue fibrosis and disease severity.

Keywords: acute and chronic pancreatitis, tissue regeneration, macrophage polarization, Gastroenterology

Procedia PDF Downloads 49

Authors: Bhavita S. Dave, Chandresh H. Solanki, Atul K. Desai

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Soils of Greater Himalayas mostly pertain to Leh & Ladakh, Lahaul & Sppiti, & high reaches to Uttarakhand. The moisture regime is aridic. The arid zone starts from Baralacha pass in Lahaul and covers the entire Spiti valley in the district of Lahaul & Spiti, Himachal Pradesh of India. Here, the present study is an attempt to determine the suction value of soil collected from the arid zone of Spiti valley for different freezing-thawing cycles considering the climate ranges of Spiti valley. Suction is the basic and most important parameter which influences the behavior of unsaturated soil. It is essential to determine the suction value of unsaturated soil before other tests like shear test, and permeability. Basically, it is the negative pore water pressure in partially saturated soil measured in terms of the height of the water column. The filter paper method has been used for the study as an economical approach to evaluate suction. It is the only method from which both contact and non-contact suction can be deduced. In this study, soil specimens were subjected to 0, 1, 3, & 5 freezing-thawing (F-T) cycles for different degrees of saturation to have a wide range of suction, and soil freezing characteristic curves (SFCC) were formulated for all F-T cycles. The result data collected from the experiments have shown best-fitted values using Fredlund & Xing model for each SFCC.

Keywords: suction, arid region soil, soil freezing characteristic curve, freezing-thawing cycle

Procedia PDF Downloads 208

Authors: Boce Zhang

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Strategic innovation of nanotechnology to promote food safety has drawn tremendous attentions among research groups, which includes the need for research support during the implementation of the Food Safety Modernization Act (FSMA) in the United States. There are urgent demands and knowledge gaps to the understanding of a) food-water-bacteria interface as for how pathogens persist and transmit during food processing and storage; b) minimum processing requirement needed to prevent pathogen cross-contamination in the food system. These knowledge gaps are of critical importance to the food industry. However, the lack of knowledge is largely hindered by the limitations of research tools. Our groups recently endeavored two novel engineering systems with biomimetics and microfluidics as a holistic approach to hazard analysis and risk mitigation, which provided unprecedented research opportunities to study pathogen behavior, in particular, contamination, and cross-contamination, at the critical food-water-pathogen interface. First, biomimetically-patterned surfaces (BPS) were developed to replicate the identical surface topography and chemistry of a natural food surface. We demonstrated that BPS is a superior research tool that empowers the study of a) how pathogens persist through sanitizer treatment, b) how to apply fluidic shear-force and surface tension to increase the vulnerability of the bacterial cells, by detaching them from a protected area, etc. Secondly, microfluidic devices were designed and fabricated to study the bactericidal kinetics in the sub-second time frame (0.1~1 second). The sub-second kinetics is critical because the cross-contamination process, which includes detachment, migration, and reattachment, can occur in a very short timeframe. With this microfluidic device, we were able to simulate and study these sub-second cross-contamination scenarios, and to further investigate the minimum sanitizer concentration needed to sufficiently prevent pathogen cross-contamination during the food processing. We anticipate that the findings from these studies will provide critical insight on bacterial behavior at the food-water-cell interface, and the kinetics of bacterial inactivation from a broad range of sanitizers and processing conditions, thus facilitating the development and implementation of science-based food safety regulations and practices to mitigate the food safety risks.

Keywords: biomimetic materials, microbial food safety, microfluidic device, nanotechnology

Procedia PDF Downloads 348

Authors: Samuele Abagnato, Lucia Rigamonti

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Life-Cycle-Assessment (LCA) is an effective tool to quantify the environmental impacts of reuse models and recycling technologies for textiles. In this work, publications in the last ten years about LCA on textile waste are classified according to location, goal and scope, functional unit, waste composition, impact assessment method, impact categories, and sensitivity analysis. Twenty papers have been selected: 50% are focused only on recycling, 30% only on reuse, the 15% on both, while only one paper considers only the final disposal of the waste. It is found that reuse is generally the best way to decrease the environmental impacts of textiles waste management because of the avoided impacts of manufacturing a new item. In the comparison between a product made with recycled yarns and a product from virgin materials, in general, the first option is less impact, especially for the categories of climate change, water depletion, and land occupation, while for other categories, such as eutrophication or ecotoxicity, under certain conditions the impacts of the recycled fibres can be higher. Cultivation seems to have quite high impacts when natural fibres are involved, especially in the land use and water depletion categories, while manufacturing requires a remarkable amount of electricity, with its associated impact on climate change. In the analysis of the reuse processes, relevant importance is covered by the laundry phase, with water consumption and impacts related to the use of detergents. About the sensitivity analysis, it can be stated that one of the main variables that influence the LCA results and that needs to be further investigated in the modeling of the LCA system about this topic is the substitution rate between recycled and virgin fibres, that is the amount of recycled material that can be used in place of virgin one. Related to this, also the yield of the recycling processes has a strong influence on the results of the impact. The substitution rate is also important in the modeling of the reuse processes because it represents the number of avoided new items bought in place of the reused ones. Another aspect that appears to have a large influence on the impacts is consumer behaviour during the use phase (for example, the number of uses between two laundry cycles). In conclusion, to have a deeper knowledge of the impacts of a life-cycle approach of textile waste, further data and research are needed in the modeling of the substitution rate and of the use phase habits of the consumers.

Keywords: environmental impacts, life-cycle-assessment, textiles recycling, textiles reuse, textiles waste management

Procedia PDF Downloads 76

Authors: S. Fadda, M. Fiori, C. Matzuzzi

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Mineralized formations in the bottom sediments of a Miocene transgression have been discovered in Sardinia. The mineral assemblage consists of copper sulphides and oxidates suggesting fluctuations of redox conditions in neutral to high-pH restricted shallow-water coastal basins. Azurite/malachite has been observed as authigenic and occurs as loose spheroidal crystalline particles associated with the transitional-littoral horizon forming the bottom of the marine transgression. Many field observations are consistent with a supergenic circulation of metals involving terrestrial groundwater-seawater mixing. Both clastic materials and metals come from Tertiary volcanic edifices while the main precipitating anions, carbonates, and sulphides species are of both continental and marine origin. Formation of Cu carbonates as a supergene secondary 'oxide' assemblage, does not agree with field evidences, petrographic observations along with textural evidences in the host-rock types. Samples were collected along the sedimentary sequence for different analyses: the majority of elements were determined by X-ray fluorescence and plasma-atomic emission spectroscopy. Mineral identification was obtained by X-ray diffractometry and scanning electron microprobe. Thin sections of the samples were examined in microscopy while porosity measurements were made using a mercury intrusion porosimeter. Cu-carbonates deposited at a temperature below 100 C° which is consistent with the clay minerals in the matrix of the host rock dominated by illite and montmorillonite. Azurite nodules grew during the early diagenetic stage through reaction of cupriferous solutions with CO₂ imported from the overlying groundwater and circulating through the sandstones during shallow burial. Decomposition of organic matter in the bottom anoxic waters released additional carbon dioxide to pore fluids for azurite stability. In this manner localized reducing environments were also generated in which Cu was fixed as Cu-sulphide and sulphosalts. Microscopic examinations of textural features of azurite nodules give evidence of primary malachite/azurite deposition rather than supergene oxidation in place of primary sulfides. Photomicrographs show nuclei of azurite and malachite surrounded by newly formed microcrystalline carbonates which constitute the matrix. The typical pleochroism of crystals can be observed also when this mineral fills microscopic fissures or cracks. Sedimentological evidence of transgression and regression indicates that the pore water would have been a variable mixture of marine water and groundwaters with a possible meteoric component in an alternatively exposed and subaqueous environment owing to water-level fluctuation. Salinity data of the pore fluids, assessed at random intervals along the mineralised strata confirmed the values between about 7000 and 30,000 ppm measured in coeval sediments at the base of Miocene falling in the range of a more or less diluted sea water. This suggests a variation in mean pore-fluids pH between 5.5 and 8.5, compatible with the oxidized and reduced mineral paragenesis described in this work. The results of stable isotopes studies reflect the marine transgressive-regressive cyclicity of events and are compatibile with carbon derivation from sea water. During the last oxidative stage of diagenesis, under surface conditions of higher activity of H₂O and O₂, CO₂ partial pressure decreased, and malachite becomes the stable Cu mineral. The potential for these small but high grade deposits does exist.

Keywords: sedimentary, Cu-carbonates, authigenic, tertiary, Sardinia

Procedia PDF Downloads 120

Authors: Aslanova Aida Ramiz

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One of the important aspects of rheophysical problems in oil and gas extraction is the regulation of thermohydrodynamic properties of liquid systems using physical and physicochemical methods. It is known that the constituent parts of real fluid systems in oil and gas production are practically non-conducting, non-magnetically active components. Real heterogeneous hydrocarbon systems, from the structural point of view, consist of an infinite number of microscopic local ion-electrostatic cores distributed in the volume of the dispersion medium. According to Cohen's rule, double electric layers are formed at the contact boundaries of components in contact (oil-gas, oil-water, water-condensate, etc.) in a heterogeneous system, and as a result, each real fluid system can be represented as a complex composition of a set of local electrostatic fields. The electrokinetic properties of this structure are characterized by a certain electrode potential. Prof. F.H. Valiyev called this potential the α-factor and came up with the idea that many natural and technological rheophysical processes (effects) are essentially electrokinetic in nature, and by changing the α-factor, it is possible to adjust the physical properties of real hydraulic systems, including thermohydrodynamic parameters. Based on this idea, extensive research work was conducted, and the possibility of reducing hydraulic resistances and improving rheological properties was experimentally discovered in real liquid systems by reducing the electrical potential with various physical and chemical methods.

Keywords: microcracked, electrode potential, hydraulic resistance, Newtonian fluid, rheophysical properties

Procedia PDF Downloads 60

Authors: Yuan Wan, Shumei Cui, Shaopeng Wu

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Toroidal windings were taken advantage of to reduce of axial length of the motor, so as to match the applications that have severe restrictions on the axial length. But slotting in the out edge of the stator will decrease the heat-dissipation capacity of the water cooling of the housing. Besides, the windings in the outer slots will increase the copper loss, which will further increase the difficult for heat dissipation of the motor. At present, carbon-fiber composite retaining sleeve are increasingly used to be mounted over the magnets to ensure the rotor strength at high speeds. Due to the poor thermal conductivity of carbon-fiber sleeve, the cooling of the rotor becomes very difficult, which may result in the irreversible demagnetization of magnets for the excessively high temperature. So it is necessary to analyze the temperature rise of such motor. This paper builds a computational fluid dynamic (CFD) model of a toroidal-winding high-speed permanent magnet synchronous motor (PMSM) with water cooling of housing and forced air cooling of rotor. Thermal analysis was carried out based on the model and the factors that affects the temperature rise were investigated. Then thermal optimization for the prototype was achieved. Finally, a small-size prototype was manufactured and the thermal analysis results were verified.

Keywords: thermal analysis, temperature rise, toroidal windings, high-speed PMSM, CFD

Procedia PDF Downloads 479