Search results for: acid soils

Authors: H. Taheri Shahraiyni, B. Ataie Ashtiani

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Flow movement in unsaturated soil can be expressed by a partial differential equation, named Richards equation. The objective of this study is the finding of an appropriate implicit numerical solution for head based Richards equation. Some of the well known finite difference schemes (fully implicit, Crank Nicolson and Runge-Kutta) have been utilized in this study. In addition, the effects of different approximations of moisture capacity function, convergence criteria and time stepping methods were evaluated. Two different infiltration problems were solved to investigate the performance of different schemes. These problems include of vertical water flow in a wet and very dry soils. The numerical solutions of two problems were compared using four evaluation criteria and the results of comparisons showed that fully implicit scheme is better than the other schemes. In addition, utilizing of standard chord slope method for approximation of moisture capacity function, automatic time stepping method and difference between two successive iterations as convergence criterion in the fully implicit scheme can lead to better and more reliable results for simulation of fluid movement in different unsaturated soils.

Keywords: Finite Difference methods, Richards equation, fullyimplicit, Crank-Nicolson, Runge-Kutta.

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Authors: Addion Nizori, Lan T.T. Bui, Darryl M. Small

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Ascorbic acid (AA), commonly known as vitamin C, is essential for normal functioning of the body and maintenance of metabolic integrity. Among its various roles are as an antioxidant, a cofactor in collagen formation and other reactions, as well as reducing physical stress and maintenance of the immune system. Recent collaborative research between the Australian Defence Science and Technology Organisation (DSTO) in Scottsdale, Tasmania and RMIT University has sought to overcome the problems arising from the inherent instability of ascorbic acid during processing and storage of foods. The recent work has demonstrated the potential of microencapsulation by spray drying as a means to enhance retention. The purpose of this current study has been focused upon the influence of spray drying conditions on the properties of encapsulated ascorbic acid. The process was carried out according to a central composite design. Independent variables were: inlet temperature (80-120° C) and feed flow rate (7-14 mL/minute). Process yield, ascorbic acid loss, moisture content, water activity and particle size distribution were analysed as responses. The results have demonstrated the potential of microencapsulation by spray drying as a means to enhance retention. Vitamin retention, moisture content, water activity and process yield were influenced positively by inlet air temperature and negatively by feed flow rate.

Keywords: Microencapsulation, spray drying, ascorbic acid.

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Authors: F. Halek, A. Kavousi, M. Banifatemi

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There is growing interest in biodiesel (fatty acid methyl ester or FAME) because of the similarity in its properties when compared to those of diesel fuels. Diesel engines operated on biodiesel have lower emissions of carbon monoxide, unburned hydrocarbons, particulate matter, and air toxics than when operated on petroleum-based diesel fuel. Production of fatty acid methyl ester (FAME) from rapeseed (nonedible oil) fatty acid distillate having high free fatty acids (FFA) was investigated in this work. Conditions for esterification process of rapeseed oil were 1.8 % H2SO4 as catalyst, MeOH/oil of molar ratio 2 : 0.1 and reaction temperature 65 °C, for a period of 3h. The yield of methyl ester was > 90 % in 1 h. The amount of FFA was reduced from 93 wt % to less than 2 wt % at the end of the esterification process. The FAME was pureed by neutralization with 1 M sodium hydroxide in water solution at a reaction temperature of 62 °C. The final FAME product met with the biodiesel quality standard, and ASTM D 6751.

Keywords: Alternative Fuels, Biodiesel, Fatty Acid, MethylEster, Seed Oil, Transesterification.

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Authors: Ayat Bani Rashaid, Zain Khasawneh, Mazin Alqhazo, Shreen Nusair, Mohammad El-Khateeb, Mahmoud Bashtawi

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Autism Spectrum disorder (ASD) is a psychiatric disorder with unknown etiology that mainly affects children in the first three years of life. Alterations of amino acid levels are believed to contribute to ASD. The levels of six essential amino acids (methionine, histidine, valine, leucine, threonine, and phenylalanine), five conditional amino acids (proline, tyrosine, glutamine, cysteine, and cystine), and five non-essential amino acids (asparagine, aspartic acid, alanine, serine, and glutamic acid) in hair samples of children with ASD (n = 25) were analyzed and compared to corresponding levels in healthy age-matched controls (n = 25). The results showed that the levels of methionine, alanine, and asparagine were significantly lower in the hair samples of ASD group compared to those of the control group (p ≤ 0.05). However, the levels of glutamic acid were significantly higher in the ASD group than the control group (p ≤ 0.05). The current findings could contribute towards further understanding of ASD etiology and provide specialists with a hair amino acid profile utilized as a biomarker for early diagnosis of ASD. Such biomarkers could participate in future developments of therapies that reduce ASD-related symptoms.

Keywords: Autism spectrum disorder, amino acids, liquid chromatography-tandem mass spectrometry, human hair.

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Authors: D. M. Cocârță, I. A. Istrate, C. Streche, D. M. Dumitru

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Soil contamination phenomena are a wide world issue that has received the important attention in the last decades. The main pollutants that have affected soils are especially those resulted from the oil extraction, transport and processing. This paper presents results obtained in the framework of a research project focused on the management of contaminated sites with petroleum products/ REMPET. One of the specific objectives of the REMPET project was to assess the electrochemical treatment (improved with polarity change respect to the typical approach) as a treatment option for the remediation of total petroleum hydrocarbons (TPHs) from contaminated soils. Petroleum hydrocarbon compounds attach to soil components and are difficult to remove and degrade. Electrochemical treatment is a physicochemical treatment that has gained acceptance as an alternative method, for the remediation of organic contaminated soils comparing with the traditional methods as bioremediation and chemical oxidation. This type of treatment need short time and have high removal efficiency, being usually applied in heterogeneous soils with low permeability. During the experimental tests, the following parameters were monitored: pH, redox potential, humidity, current intensity, energy consumption. The electrochemical method was applied in an experimental setup with the next dimensions: 450 mm x 150 mm x 150 mm (L x l x h). The setup length was devised in three electrochemical cells that were connected at two power supplies. The power supplies configuration was provided in such manner that each cell has a cathode and an anode without overlapping. The initial value of TPH concentration in soil was of 1420.28 mg/kg_dw. The remediation method has been applied for only 21 days, when it was already noticed an average removal efficiency of 31 %, with better results in the anode area respect to the cathode one (33% respect to 27%). The energy consumption registered after the development of the experiment was 10.6 kWh for exterior power supply and 16.1 kWh for the interior one. Taking into account that at national level, the most used methods for soil remediation are bioremediation (which needs too much time to be implemented and depends on many factors) and thermal desorption (which involves high costs in order to be implemented), the study of electrochemical treatment will give an alternative to these two methods (and their limitations).

Keywords: Electrochemical remediation, pollution, soil contamination, total petroleum hydrocarbons

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Authors: Marwa H. Mahmoud, Ferial M. Abu-Salem

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Soy protein is a common ingredient added to processed meats to enhance its functional characteristics. In our study, soybean products (fermented soy Natto and protein hydrolysate) containing hydrolyzed peptides and amino acids, with or without ascorbic acid were added to burger in order to improve its quality characteristics. Results showed that soy additives significantly increased moisture and protein content and reduced (P < 0.05) fat values. Ash content did not affect with Natto additive. Color tools, lightness and yellowness were higher (P<0.05) for the samples with added soybean products (with or without ascorbic acid), while redness decreased. Both of protein hydrolysate and ascorbic acid increased the softiness while, Natto additive increased the hardness of samples. Natto & protein hydrolysate additives increased the total volatile basic nitrogen while, samples with ascorbic acid decreased TVBN values at significant levels. Also, soy additives were improved both of cooking quality and sensory evaluation of the burger in order to prove that soy products actually affect the quality characteristics of meat products.

Keywords: Burger, protein hydrolysate, fermented soy Natto, quality characterization.

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Authors: Sevil Yucel, Zafer Omer Ozdemir, Cem Kesgin, Pinar Terzioglu, Simten Unlu, Yagmur Erdogan, Kubra Pusat

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Chitosan is an attractive polysaccharide obtained by deacetylation of an abundant natural biopolymer called chitin. Chitin and chitosan are excellent materials. To improve the potential of chitin and chitosan modification is needed. In the present study, grafting of maleic acid on to chitosan by cerium ammonium nitrate in acetic acid solution was investigated with use of a microwave and reflux system. The grafted chitosan was characterized by using a Fourier-transform infrared spectrometry. The solubility and swelling behavior of grafted chitosans were determined in acetate buffer (pH 3.6), citrophosphate buffer (pH 5.6 and pH 7.0), and boric buffer (pH 9.2) solutions. The sample obtained by microwave system with use of a chitosan/maleic anhydride/ceric ammonium nitrate 0.2/3.922/0.99 gram of raw material within 30 minute showed the maximum swelling ratio (13.6) in boric buffer solution.

Keywords: Chitosan, cytotoxicity, grafted, maleic acid, swell.

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Authors: Romel N. Georgees, Rayya A Hassan, Robert P. Evans, Piratheepan Jegatheesan

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Among other traditional and non-traditional additives, polymers have shown an efficient performance in the field and improved sustainability. Polyacrylamide (PAM) is one such additive that has demonstrated many advantages including a reduction in permeability, an increase in durability and the provision of strength characteristics. However, information about its effect on the improved geotechnical characteristics is very limited to the field performance monitoring. Therefore, a laboratory investigation was carried out to examine the basic and engineering behaviors of three types of soils treated with a PAM additive. The results showed an increase in dry density and unconfined compressive strength for all the soils. The results further demonstrated an increase in unsoaked CBR and a reduction in permeability for all stabilized samples.

Keywords: CBR, Hydraulic conductivity, PAM, Unconfined compressive strength.

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Authors: Hamed Sadeghi, Pouya A. Panahi, Hamed Nasiri, Mohammad Sadeghi

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Collapsible soils like loess comprise an important category of problematic soils for construction purposes and sustainable development. As a result, research on both geological and geotechnical aspects of this type of soil have been in progress for decades. However, considerable natural variability in physical properties of in-situ loess strata even in a single block sample challenges the fundamental laboratory investigations. The reason behind this is that it is somehow impossible to remove the effect of a specific factor like void ratio from fair comparisons to come with a reliable conclusion. In order to cope with this limitation, two types of artificially made dispersive and calcareous loess are introduced which can be easily reproduced in any soil mechanics laboratory provided that all its compositions are known and controlled. The collapse potential is explored for a variety of soil water salinity and lime content and comparisons are made against the natural soil behavior. Trends are reported for the influence of pore water salinity on collapse potential under different osmotic flow conditions. The most important advantage of artificial loess is the ease of controlling cementing agent content like calcite or dispersive potential for studying their influence on mechanical soil behavior.

Keywords: Artificial loess, unsaturated soils, collapse potential, dispersive clays, laboratory tests.

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Authors: T. Azouaoui – Ait Kettout, R. Gaceb – Terrak, F. Rahmania

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Date production in North Africa is facing a worrying slowdown and a decline because of Fusarium wilt or bayoud date palm (Phoenix dactylifera L., caused by Fusarium oxysporum f. sp. albedinis (F. o. a). The objective of this work is to study the in vitro effect of flavonoid aglycones extracted from the roots of two cultivars of date palm (one sensitive to bayoud (Deglet Nour) and the other resistant (Takerboucht)) on the growth and production fusaric acid of the pathogen. Results show that during the first week of development of F. o. a on potato dextrose liquid medium, the flavonoid aglycones extracts of the susceptible cultivar roots stimulates mycelial growth as well as conidiogenesis of F.o.a, nevertheless it has no effect on the synthesis of fusaric acid. However, the flavonoid aglycones extract of resistant cultivar roots stimulates mycelial growth and decreases both the number of conidia production and fusaric acid. It therefore appears possible that the resistant cultivar aglycones have two types of action: they either inhibit the synthesis of fusaric acid, or they metabolize this toxin into hydrosoluble product, this is called detoxification.

Keywords: Flavonoid Aglycones, date palm, fusaric acid, Fusarium oxysporum f. sp. albedinis.

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Authors: G. M. Ayininuola, A. O. Sogunro

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Most failures of soil have been attributed to poor shear strength. Consequently, the present paper investigated the suitability of cattle bone ash as a possible additive to improve the shear strength of soils. Four soil samples were collected and stabilized with prepared bone ash in proportions of 3%, 5%, 7%, 10%, 15% and 20% by dry weight. Chemical analyses of the bone ash; followed by classification, compaction, and triaxial shear tests of the treated soil samples were conducted. Results obtained showed that bone ash contained high proportion of calcium oxide and phosphate. Addition of bone ash to soil samples led to increase in soil shear strengths within the range of 22.40% to 105.18% over the strengths of the respective control tests. Conversely, all samples attained maximum shear strengths at 7% bone ash stabilization. The use of bone ash as an additive will therefore improve the shear strength of soils; however, using bone ash quantities in excess of 7% may not yield ample results.

Keywords: Bone ash, Shear strength, Stabilization, Soil.

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Authors: A. Spanou, P. Giannouli

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The effects of coatings based on sodium alginate (S.A) and carboxyl methyl cellulose (CMC) on the color and moisture characteristics of potato round slices were investigated. It is the first time that this combination of polysaccharides is used as edible coating which alone had the best performance as inhibitor of potato color discoloration during the storage of 15 days at 4oC. When ascorbic acid (AA) and green tea (GT) were added in the above edible coating its effects on potato round slices changed. The mixtures of sodium alginate and carboxyl methyl cellulose with ascorbic acid or with green tea behave as a potential moisture barrier, resulting to the extent of potato samples self–life. These data suggests that both GT and AA are potential inhibitors of dehydration in potatoes and not only natural antioxidants.

Keywords: Ascorbic acid, edible coating, green tea, moisture barrier.

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Authors: M. Vesali Naseh, A. A. Khodadadi, Y. Mortazavi, O. Alizadeh Sahraei, F. Pourfayaz, S. Mosadegh Sedghi

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In this study, multiwall carbon nanotubes (MWNTs) were modified with nitric acid chemically and by dielectric barrier discharge (DBD) plasma in an oxygen-based atmosphere. Used carbon nanotubes (CNTs) were prepared by chemical vapour deposition (CVD) floating catalyst method. For removing amorphous carbon and metal catalyst, MWNTs were exposed to dry air and washed with hydrochloric acid. Heating purified CNTs under helium atmosphere caused elimination of acidic functional groups. Fourier transformed infrared spectroscopy (FTIR) shows formation of oxygen containing groups such as C=O and COOH. Brunauer, Emmett, Teller (BET) analysis revealed that functionalization causes generation of defects on the sidewalls and opening of the ends of CNTs. Results of temperature-programmed desorption (TPD) and gas chromatography(GC) indicate that nitric acid treatment create more acidic groups than plasma treatment.

Keywords: Carbon nanotubes (CNTs), chemical treatment, functionalization, plasma.

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Authors: Dhongkyu Yoon

Abstract:

Environmental statistics reveals that the pollution of acid rain in South Korea is a serious issue. Yet the awareness of people is low. Even after a gradual decrease of pollutant emission in Korea, the acidity has not been reduced. There no boundaries in the atmosphere are set and the influence of the neighboring countries such as China is apparent. Governmental efforts among China, Japan and Korea have been made on this issue. However, not much progress has been observed. Along with the governmental activities, therefore, an active monitoring of the pollution among the countries and the promotion of environmental awareness at the civil level including especially the middle and high schools are highly recommended. It will be this young generation who will face damaged country as inheritance not the current generation.

Keywords: acid rain, international collaboration, pollution, South Korea

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Authors: Nuttawan Yoswathana, M. N. Eshiaghi, K. Jaturapornpanich

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The traditional method for essential oil extraction from agarwood (Aquilaria Crassna) is to soak it in water and follow with hydrodistillation. The effect of various agarwood pretreatments: ethanol, acid, alkaline, enzymes, and ultrasound, and the effect of subcritical water extraction(SWE) was studied to compare with the traditional method. The major compositions of agarwood oil from hydrodistillation were aroma compounds as follow: aristol-9-en-8- one (21.53%), selina-3, 7(11)-diene (12.96%), τ-himachalene (9.28%), β-guaiene (5.79%), hexadecanoic acid (4.90%) and guaia- 3,9-diene (4.21%). Whereas agarwood oil from pretreatments with ethanol and ultrasound, and SWE got fatty acid compounds. Extraction of agarwood oil using these pretreatments could improve the agarwood oil yields up to 2 times that of the traditional method. The components of the pretreated sample with diluted acid (H2SO4) at pH 4 gave quite similar results as the traditional method. Therefore, the enhancement of essential oil from agarwood depends on requirement of type of extracted oil that involved extraction methods.

Keywords: Agarwood, aquilaria crassna, hydrodistillation, subcritical water extraction.

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Authors: Ragi Poyyara, Vijaya Patnana, Mohammed Alam

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When acid is pumped into damaged reservoirs for damage removal/stimulation, distorted inflow of acid into the formation occurs caused by acid preferentially traveling into highly permeable regions over low permeable regions, or (in general) into the path of least resistance. This can lead to poor zonal coverage and hence warrants diversion to carry out an effective placement of acid. Diversion is desirably a reversible technique of temporarily reducing the permeability of high perm zones, thereby forcing the acid into lower perm zones. The uniqueness of each reservoir can pose several challenges to engineers attempting to devise optimum and effective diversion strategies. Diversion techniques include mechanical placement and/or chemical diversion of treatment fluids, further sub-classified into ball sealers, bridge plugs, packers, particulate diverters, viscous gels, crosslinked gels, relative permeability modifiers (RPMs), foams, and/or the use of placement techniques, such as coiled tubing (CT) and the maximum pressure difference and injection rate (MAPDIR) methodology. It is not always realized that the effectiveness of diverters greatly depends on reservoir properties, such as formation type, temperature, reservoir permeability, heterogeneity, and physical well characteristics (e.g., completion type, well deviation, length of treatment interval, multiple intervals, etc.). This paper reviews the mechanisms by which each variety of diverter functions and discusses the effect of various reservoir properties on the efficiency of diversion techniques. Guidelines are recommended to help enhance productivity from zones of interest by choosing the best methods of diversion while pumping an optimized amount of treatment fluid. The success of an overall acid treatment often depends on the effectiveness of the diverting agents.

Keywords: Acid treatment, carbonate, diversion, sandstone.

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Authors: H. Aghayan, F. A. Hashemi, R. Yavari, S. Zolghadri

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In this work, a new composite adsorbent based on a mesoporous silica SBA-15 with platelet morphology and tin salt of tungstomolybdophosphoric (TWMP) acid was synthesized and applied for uranium adsorption from aqueous solution. The sample was characterized by X-ray diffraction, Fourier transfer infra-red, and N₂ adsorption-desorption analysis, and then, effect of various parameters such as concentration of metal ions and contact time on adsorption behavior was examined. The experimental result showed that the adsorption process was explained by the Langmuir isotherm model very well, and predominant reaction mechanism is physisorption. Kinetic data of adsorption suggest that the adsorption process can be described by the pseudo second-order reaction rate model.

Keywords: Platelet SBA-15, tungstomolybdophosphoric acid, adsorption, uranium ion.

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Authors: Sawangjit Sopid

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In this study sugarcane field soils with a long history of atrazine application in Chachoengsao and Chonburi provinces have been explored for their potential of atrazine biodegradation. For the atrazine degrading bacteria isolation, the soils used in this study named ACS and ACB were inoculated in MS-medium containing atrazine. Six short rod and gram-negative bacterial isolates, which were able to use this herbicide as a sole source of nitrogen, were isolated and named as ACS1, ACB1, ACB3, ACB4, ACB5 and ACB6. From the 16S rDNA nucleotide sequence analysis, the isolated bacteria ACS1 and ACB4 were identified as Rhizobium sp. with 89.1-98.7% nucleotide identity, ACB1 and ACB5 were identified as Stenotrophomonas sp. with 91.0-92.8% nucleotide identity, whereas ACB3 and ACB6 were Klebsiella sp. with 97.4-97.8% nucleotide identity.

Keywords: Atrazine-degrading bacteria, bioremediation, Thai isolate bacteria.

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Authors: Jong Ho Hwang, Dae Hwan Kang, Young-IL Jeong

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Since hyaluronic acid (HA) receptor such as CD44 is over-expressed at sites of cancer cells, HA can be used as a targeting vehicles for anti-cancer drugs. The aim of this study is to synthesize block copolymer composed of hyaluronic acid and poly(ε-caprolactone) (HAPCL) and to fabricate polymeric micelles for anticancer drug targeting against CD44 receptor of tumor cells. Chemical composition of HAPCL was confirmed using 1H NMR spectroscopy. Doxorubicin (DOX) was incorporated into polymeric micelles of HAPCL. The diameters of HAPHS polymeric micelles were changed around 80nm and have spherical shapes. Targeting potential was investigated using CD44-overexpressing. When DOX-incorporated polymeric micelles was added to KB cells, they revealed strong red fluorescence color while blocking of CD44 receptor by pretreatment of free HA resulted in reduced intensity, indicating that HAPCL polymeric micelles have targetability against CD44 receptor.

Keywords: Hyaluronic acid, CD44 receptor, biorecognizable nanoparticles, block copolymer.

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Authors: F. Ardestani, S. S. A. Fatemi, B. Yakhchali

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Mycophenolic acid (MPA) is a secondary metabolite produced by Penicillium brevicompactum, which has antibiotic and immunosuppressive properties. In this study, the first, mycophenolic acid was produced in a fermentation process by Penicillium brevicompactum MUCL 19011 in shake flask using a base medium. The maximum MPA production, product yield and productivity of process were 1.379 g/L, 18.6 mg/g glucose and 4.9 mg/L. h, respectively. Also the glucose consumption, biomass and MPA production profiles were investigated during batch cultivation. Obtained results showed that MPA production starts approximately after 180 hours and reaches to a maximum at 280 h. In the next step, the effects of some various concentrations of enzymatically hydrolyzed casein on MPA production were evaluated. Maximum MPA production, product yield and productivity as 3.63 g/L, 49 mg/g glucose and 12.96 mg/L.h, respectively were obtained with using 30 g/L enzymatically hydrolyzed casein in culture medium. These values show an enhanced MPA production, product yield and process productivity pr as 116.8%, 132.8% and 163.2%, respectively.

Keywords: Penicillium brevicompactum, Enzymatically hydrolyzed casein, Mycophenolic acid, Submerged culture

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Authors: Ákos Wolf, Richard P. Ray

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Due to the introduction of Eurocode 8, the structural design for seismic and dynamic effects has become more significant in Hungary. This has emphasized the need for more effort to describe the behavior of structures under these conditions. Soil conditions have a significant effect on the response of structures by modifying the stiffness and damping of the soil-structural system and by modifying the seismic action as it reaches the ground surface. Shear modulus (G) and shear wave velocity (v_s), which are often measured in the field, are the fundamental dynamic soil properties for foundation vibration problems, liquefaction potential and earthquake site response analysis. There are several laboratory and in-situ measurement techniques to evaluate dynamic soil properties, but unfortunately, they are often too expensive for general design practice. However, a significant number of correlations have been proposed to determine shear wave velocity or shear modulus from Cone Penetration Tests (CPT), which are used more and more in geotechnical design practice in Hungary. This allows the designer to analyze and compare CPT and seismic test result in order to select the best correlation equations for Hungarian soils and to improve the recommendations for the Hungarian geologic conditions. Based on a literature review, as well as research experience in Hungary, the influence of various parameters on the accuracy of results will be shown. This study can serve as a basis for selecting and modifying correlation equations for Hungarian soils. Test data are taken from seven locations in Hungary with similar geologic conditions. The shear wave velocity values were measured by seismic CPT. Several factors are analyzed including soil type, behavior index, measurement depth, geologic age etc. for their effect on the accuracy of predictions. The final results show an improved prediction method for Hungarian soils

Keywords: CPT correlation, dynamic soil properties, seismic CPT, shear wave velocity.

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Authors: B. Sohbi, M. Meakaff, M. Emtir, M. Elgarni

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Natural gas is defined as gas obtained from a natural underground reservoir. It generally contains a large quantity of methane along with heavier hydrocarbons such as ethane, propane, isobutene, normal butane; also in the raw state it often contains a considerable amount of non hydrocarbons, such as nitrogen and the acid gases (carbon dioxide and hydrogen sulfide). The acid gases must be removed from natural gas before use. One of the processes witch are use in the industry to remove the acid gases from natural gas is the use of alkanolamine process. In this present paper, a simulation study for an industrial gas sweetening plant has been investigated. The aim of the study is to investigate the effect of using mixing amines as solvent on the gas treatment process using the software Hysys.

Keywords: Natural gas, alkanolamine process, gas sweetening plant, simulation, mixing amines.

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Authors: Ayfer Kilicarslan, Kubra Onol, Sercan Basit, Muhlis Nezihi Saridede

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Chalcopyrite (CuFeS2) is the most common primary mineral used for the commercial production of copper. The low dissolution efficiency of chalcopyrite in sulfate media has prevented an efficient industrial leaching of this mineral in sulfate media. Ferric ions, bacteria, oxygen and other oxidants have been used as oxidizing agents in the leaching of chalcopyrite in sulfate and chloride media under atmospheric or pressure leaching conditions. Two leaching methods were studied to evaluate chalcopyrite (CuFeS2) dissolution in acid media. First, the conventional oxidative acid leaching method was carried out using sulfuric acid (H2SO4) and potassium dichromate (K2Cr2O7) as oxidant at atmospheric pressure. Second, microwave-assisted acid leaching was performed using the microwave accelerated reaction system (MARS) for same reaction media. Parameters affecting the copper extraction such as leaching time, leaching temperature, concentration of H2SO4 and concentration of K2Cr2O7 were investigated. The results of conventional acid leaching experiments were compared to the microwave leaching method. It was found that the copper extraction obtained under high temperature and high concentrations of oxidant with microwave leaching is higher than those obtained conventionally. 81% copper extraction was obtained by the conventional oxidative acid leaching method in 180 min, with the concentration of 0.3 mol/L K2Cr2O7 in 0.5M H2SO4 at 50 ºC, while 93.5% copper extraction was obtained in 60 min with microwave leaching method under same conditions.

Keywords: Extraction, copper, microwave-assisted leaching, chalcopyrite, potassium dichromate.

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Authors: Sara Soltanpour, Adolfo Foriero

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Frost heave is arguably the most problematic adverse phenomenon in cold region areas. It is a complex process that depends on heat and water transfer. The coupled physical fields generate considerable heave stresses as well as deformations. In the present study, a coupled Thermal-Hydraulic-Mechanical (THM) model using COMSOL Multiphysics in frozen unsaturated soils, such as fine sand, is investigated. Particular attention to the frost heave and temperature distribution, as well as the water migrating during soil freezing, is assessed. The results obtained from the numerical simulations are consistent with the results measured in the full-scale tests conducted by Cold Regions Research and Engineering Laboratory (CRREL).

Keywords: Frost heave, numerical simulations, COMSOL software, unsaturated freezing soil.

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Authors: Václav Voltr, Jan Leština

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The basis of examines is survey of 500 in the years 2002-2010, which was selected according to homogeneity of land cover and where 1090 revenues were evaluated. For achieved yields of winter wheat is obtained multicriterial regression function depending on the major factors influencing the consumption of nitrogen. The coefficient of discrimination of the established model is 0.722. The increase in efficiency of fertilization is involved in supply of organic nutrients, tillage, soil pH, past weather, the humus content in the subsoil and grain content to 0.001 mm. The decrease in efficiency was mainly influenced by the total dose of mineral nitrogen, although it was divided into multiple doses, the proportion loamy particles up to 0.01 mm, rainy, or conversely dry weather during the vegetation. The efficiency of nitrogen was found to be the smallest on undeveloped soils and the highest on chernozem and alluvial soils.

Keywords: Nitrogen efficiency, winter wheat, regression model

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Authors: F. Ardestani, S.A. Fatemi, B. Yakhchali, M. Hosseyni, G. Najafpour

Abstract:

Mycophenolic acid “MPA" is a secondary metabolite of Penicillium bervicompactum with antibiotic and immunosuppressive properties. In this study, fermentation process was established for production of mycophenolic acid by Penicillium bervicompactum MUCL 19011 in shake flask. The maximum MPA production, product yield and productivity were 1.379 g/L, 18.6 mg/g glucose and 4.9 mg/L.h respectively. Glucose consumption, biomass and MPA production profiles were investigated during fermentation time. It was found that MPA production starts approximately after 180 hours and reaches to a maximum at 280 h. In the next step, the effects of methionine and acetate concentrations on MPA production were evaluated. Maximum MPA production, product yield and productivity (1.763 g/L, 23.8 mg/g glucose and 6.30 mg/L. h respectively) were obtained with using 2.5 g/L methionine in culture medium. Further addition of methionine had not more positive effect on MPA production. Finally, results showed that the addition of acetate to the culture medium had not any observable effect on MPA production.

Keywords: Penicillium bervicompactum, Methionine, Mycophenolic acid, Submerged culture

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Authors: Ryoko Yoshida, Jyunpei Yoshida, Hua Fang Yu, Yasushi Sasaki, Tetsuya Nagasaka

Abstract:

Phosphorous is an important element for agriculture and industry and is a non-renewable resource. Especially, yellow phosphorus is an essential material in advanced industrial technology, but phosphorus resources were not produced in Japan at all, and all depend on imports. It has been suggested, however, that the remaining accessible reserves of phosphate ore will be depleted within 50 years. Therefore, alternative resources for phosphate ore must be found. In this research, we have developed a process that enables the production of high-purity yellow phosphorus from domestic unused phosphorus resources such as steelmaking slags. The process consists of two parts: (1) the production of crude phosphoric acid from wastes such as steelmaking slag; (2) producing high-purity yellow phosphorus by low-temperature carbothermic reduction of phosphoric acid (H₃PO₄). The details of the carbothermic reduction of phosphoric acid are presented in this paper. Yellow phosphorus is commercially produced by carbothermic reduction of phosphate ore in an electric arc furnace at more than 1673K. In the newly developed system, gaseous P₄O₁₀ evaporated from H₃PO₄ is successfully reduced to yellow phosphorus by using carbon packed bed at less than 1273K. To meet the depletion of phosphate ore, the proposed process in this study to produce yellow phosphorus by carbothermic reduction of H₃PO₄ that are extracted from dephosphorization slags will be one of the effective and economical solutions.

Keywords: Carbothermic reduction, dephosphorization slags, phosphoric acid, yellow phosphorus.

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Authors: David L. Azevedo, Jordan Del Nero

Abstract:

In this paper we study a system composed by carbon nanotube (CNT) and bundle of carbon nanotube (BuCNT) interacting with a specific fatty acid as molecular probe. Full system is represented by open nanotube (or nanotubes) and the linoleic acid (LA) relaxing due the interaction with CNT and BuCNT. The LA has in his form an asymmetric shape with COOH termination provoking a close BuCNT interaction mainly by van der Waals force field. The simulations were performed by classical molecular dynamics with standard parameterizations. Our results show that these BuCNT and CNT are dynamically stable and it shows a preferential interaction position with LA resulting in three features: (i) when the LA is interacting with CNT and BuCNT (including both termination, CH2 or COOH), the LA is repelled; (ii) when the LA terminated with CH2 is closer to open extremity of BuCNT, the LA is also repelled by the interaction between them; and (iii) when the LA terminated with COOH is closer to open extremity of BuCNT, the LA is encapsulated by the BuCNT. These simulations are part of a more extensive work on searching efficient selective molecular devices and could be useful to reach this goal.

Keywords: Carbon Nanotube, Linoleic Acid, MolecularDynamics.

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Authors: Mourad Makhlouf, Omar Bouchher, Messabih Sidi Mohamed, Benrachedi Khaled

Abstract:

The objective of this study was to investigate the removal of two organic pollutants; 4-hydroxybenzoic acid (p-hydroxybenzoic acid) and phenol from synthetic wastewater by the adsorption on mesoporous materials. In this context, the aim of this work is to study the adsorption of organic compounds phenol and 4AHB on MCM-41 and FSM-16 non-grafted (NG) and other grafted (G) by trimethylchlorosilane (TMCS). The results of phenol and 4AHB adsorption in aqueous solution show that the adsorption capacity tends to increase after grafting in relation to the increase in hydrophobicity. The materials are distinguished by a higher adsorption capacity to the other NG materials. The difference in the phenol is 14.43% (MCM-41), 14.55% (FSM-16), and 16.72% (MCM-41), 13.57% (FSM-16) in the 4AHB. Our adsorption results show that the grafted materials by TMCS are good adsorbent at 25 °C.

Keywords: MCM-41, FSM-16, TMCS, phenol, 4AHB.

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Authors: Pramote Paengkoum, Y. Han , S. Traiyakun, J. Khotsakdee, S. Paengkoum

Abstract:

This experiment was performed with the purpose of investigating effect of additional blend of probiotics Saccharomyces cerevisiae and Lactobacillus acidophilus on plasma fatty acid profiles particularly conjugated linoleic acid (CLA) in growing goats fed corn silage, and selected the optimal levels of the probiotics for further study. Twenty-four growing crossbred (Thai native x Anglo-Nubian) goats that weighed (14.2 ± 2.3) kg, aged about 6 months, were purchased and allocated to 4 treatments according to Randomized Complete Block Design (RCBD) with 6 goats in each treatment. The blocks were made by weight into heavy, medium, and light goats and each of the treatments contained two goats from each of the blocks. In the mean time, ruminal average pH unaffected, but the NH3-N and also plasma urea nitrogen (p<0.05), total volatile fatty acid (p>0.05) were raised, but propionic proportion (p<0.05) and butyric proportion (p>0.05) were reduced in concurrent with raise of acetic proportion and resultantly C2:C3 ratio (p>0.05). On plasma fatty acid profiles, total saturated fatty acids (p>0.05) was increased, and contrasted with decrease of C15:0 (p<0.01), C16:0 (p>0.05), and C18-C22 polyunsaturated fatty acids (p<0.05 or p<0.01). In addition, the experiment proved that the supplemented probiotics was in force for heightening CLA (p<0.01); for raising desirable fatty acids (p<0.05); for reducing ratio of PUFA: SFA (p>0.05) and for raising ratio of n6:n3 (p<0.05).

Keywords: Probiotic, conjugated linoleic acid, plasma fattyacid, goats

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