Journal of Chemistry The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. Magnetic Solid Phase Extraction Applied to Food Analysis Mon, 05 Oct 2015 13:06:16 +0000 Magnetic solid phase extraction has been used as pretreatment technique for the analysis of several compounds because of its advantages when it is compared with classic methods. This methodology is based on the use of magnetic solids as adsorbents for preconcentration of different analytes from complex matrices. Magnetic solid phase extraction minimizes the use of additional steps such as precipitation, centrifugation, and filtration which decreases the manipulation of the sample. In this review, we describe the main procedures used for synthesis, characterization, and application of this pretreatment technique which were applied in food analysis. Israel S. Ibarra, Jose A. Rodriguez, Carlos A. Galán-Vidal, Alberto Cepeda, and Jose M. Miranda Copyright © 2015 Israel S. Ibarra et al. All rights reserved. Simultaneous Determination of Lactulose and Lactose in Conserved Milk by HPLC-RID Mon, 05 Oct 2015 13:05:05 +0000 Heat treatment is applied to dairy products to ensure microbiological quality and increase the shelf life. However, a suitable control of this process is necessary to guarantee nutritional and sensory quality. The aim of this study is to adapt the high performance liquid chromatography (HPLC) method for determination of lactulose and lactose content in commercial samples of UHT and sweetened condensed milk. The HPLC method used showed a good resolution of the analytes evaluated. The analyzed UHT milk samples presented levels for lactulose in accordance with the limit recommended by the International Dairy Federation. There was no significant variation in lactulose concentration for sweetened condensed milk samples. However, one sweetened condensed milk sample showed lactose level lower than the established values (10–12%). Michelle Fernandes Silveira, Lourdes Maria Pessôa Masson, José Francisco Pereira Martins, Thiago da Silveira Álvares, Vânia Margaret Flosi Paschoalin, César Lázaro de la Torre, and Carlos Adam Conte-Junior Copyright © 2015 Michelle Fernandes Silveira et al. All rights reserved. Occurrence and Remediation of Pollutants in the Environment Mon, 05 Oct 2015 07:31:18 +0000 Núria Fontanals, Rathinam A. James, Yong Sik Ok, Malini Balakrishnan, and Jimmy T. Efird Copyright © 2015 Núria Fontanals et al. All rights reserved. Polymer Drilling Fluid with Micron-Grade Cenosphere for Deep Coal Seam Sun, 04 Oct 2015 13:45:56 +0000 Traditional shallow coal seam uses clean water, solid-free system, and foam system as drilling fluid, while they are not suitable for deep coal seam drilling due to mismatching density, insufficient bearing capacity, and poor reservoir protection effect. According to the existing problems of drilling fluid, micron-grade cenosphere with high bearing capacity and ultralow true density is selected as density regulator; it, together with polymer “XC + CMC” and some other auxiliary agents, is jointly used to build micron-grade polymer drilling fluid with cenosphere which is suitable for deep coal seam. Basic performance test shows that the drilling fluid has good rheological property, low filtration loss, good density adjustability, shear thinning, and thixotropy; besides, drilling fluid flow is in line with the power law rheological model. Compared with traditional drilling fluid, dispersion stability basically does not change within 26 h; settlement stability evaluated with two methods only shows a small amount of change; permeability recovery rate evaluated with Qinshui Basin deep coal seam core exceeds 80%. Polymer drilling fluid with cenosphere provides a new thought to solve the problem of drilling fluid density and pressure for deep coal seam drilling and also effectively improves the performance of reservoir protection ability. Peng Xu, Han-qiao Xiong, Xiao-lin Pu, Ju-quan Liu, and Xing Liu Copyright © 2015 Peng Xu et al. All rights reserved. Competitive and Noncompetitive Batch Sorption Studies of Aqueous Cd(II) and Pb(II) Uptake onto Coffea canephora Husks, Cyperus papyrus Stems, and Musa spp. Peels Sun, 04 Oct 2015 12:30:14 +0000 Coffea canephora, Cyperus papyrus, and Musa spp. were studied for competitive and noncompetitive removal of aqueous Cd2+ and Pb2+. The optimal conditions were pH 4.5 and agitation time 3.0 hours. Biomass constituent ions showed no interference effects whereas cation exchange capacity values corresponded to the sorption efficiencies. XRD spectroscopy revealed surface oxygen and nitrogen groups that provide binding sites for metal ions. The maximum sorption efficiency ranges for metal ions in noncompetitive media were 95.2–98.7% for C. canephora, 42.0–91.3% for C. papyrus, and 79.9–92.2% for Musa spp. and in competitive sorption 90.8–98.0% for C. canephora, 19.5–90.4% for C. papyrus, and 56.4–89.3% for Musa spp. The Pb2+ ions uptake was superior to that of Cd2+ ions in competitive and noncompetitive media. In competitive sorption synergistic effects were higher for Cd2+ than Pb2+ ions. The pseudo-second-order kinetic model fitted experimental data with for Pb2+ ions and for Cd2+ ions. The Langmuir model fitted noncompetitive sorption data with ; moreover the Freundlich model fitted competitive sorption data with . Noncompetitive sorption was monolayer chemisorption whereas competitive sorption exhibited heterogeneous sorption mechanisms. G. K. Bakyayita, A. C. Norrström, and R. N. Kulabako Copyright © 2015 G. K. Bakyayita et al. All rights reserved. Monitoring Antibiotic Residues and Corresponding Antibiotic Resistance Genes in an Agroecosystem Sun, 04 Oct 2015 09:11:06 +0000 Antibiotic resistance genes (ARGs) have been commonly reported due to the overuse worldwide of antibiotics. Antibiotic overuse disturbs the environment and threatens public human health. The objective of this study was to measure the residual concentrations of veterinary antibiotics in the tetracycline group (TCs), including tetracycline (TC) and chlortetracycline (CTC), as well as those in the sulfonamide group (SAs), including sulfamethazine (SMT), sulfamethoxazole (SMX), and sulfathiazole (STZ). We also isolated the corresponding ARGs in the agroecosystem. Four sediment samples and two rice paddy soil samples were collected from sites near a swine composting facility along the Naerincheon River in Hongcheon, Korea. High performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was employed with a solid-phase extraction method to measure the concentration of each antibiotic. ARGs were identified by the qualitative polymerase chain-reaction using synthetic primers. SAs and their corresponding ARGs were highly detected in sediment samples whereas TCs were not detected except for sediments sample #1. ARGs for TCs and SAs were detected in rice paddy soils, while ARGs for TCs were only found in sediment #2 and #4. Continuous monitoring of antibiotic residue and its comprehensive impact on the environment is needed to ensure environmental health. Yasser M. Awad, Kwon Rae Kim, Sung-Chul Kim, Kangjoo Kim, Sang Ryong Lee, Sang Soo Lee, and Yong Sik Ok Copyright © 2015 Yasser M. Awad et al. All rights reserved. Female Leuciscus lepidus May Be a New Alternative for Fish Oil Supplements Thu, 01 Oct 2015 13:23:02 +0000 The proximate composition of male and female Leuciscus lepidus in Beyşehir Lake was investigated. The fatty acid profiles of total lipid, phospholipid, and triacylglycerol in muscle and liver of male and female L. lepidus were evaluated by gas chromatography. Proximate analyses showed that meat of male and female L. lepidus had 15.13 ± 0.04 and 18.75 ± 0.11% fat, 20.42 ± 0.45 and 22.21 ± 0.56% protein, 65.47 ± 1.37 and 61.28 ± 1.03% moisture, and 1.51 ± 0.05 and 1.50 ± 0.03% ash, respectively. The percentage of total saturated fatty acids was higher in liver than in muscle, whereas the total polyunsaturated fatty acid (PUFA) content was the lowest in all fatty acid profiles. The phospholipids contained more PUFAs than triacylglycerol. Analysis of variance indicated significant differences () between male (47.51%) and female (49.98%) muscle PUFAs in total lipid. The proportion of omega 3 (3) to omega 6 (6) fatty acids of total lipid was 3.15 in male and 3.68 in female. The ratio is an important indicator for comparing the value of fish oil. Therefore, it was concluded that L. lepidus was considered to be a high quality product for healthy food choice. Additionally, female L. lepidus may especially be used to produce fish oil supplements from freshwater fish combined with vegetable oils. Ozlem Cakmak, Aynur Altuntas, Veli Ugurcu, Hacı Kemal Erdemli, and Sumeyya Akyol Copyright © 2015 Ozlem Cakmak et al. All rights reserved. Detection of Residual Levels and Associated Health Risk of Seven Pesticides in Fresh Eggplant and Tomato Samples from Narayanganj District, Bangladesh Thu, 01 Oct 2015 11:51:32 +0000 Residual levels of seven frequently used pesticides were investigated in 140 samples of two common vegetables, eggplants and tomatoes, from agricultural fields in the Narayanganj district of Bangladesh. The analysis of pesticide residues was performed by high-performance liquid chromatography with photodiode array detection. A large percentage of the eggplants (50%) and tomatoes (60%) from the Narayanganj district were contaminated with pesticides, and all of the levels were above the maximum residual limit (MRL) proposed by the EC regulation. Diazinon was the most common (35%) pesticide detected in the vegetable samples at a concentration of 45–450 times higher than the MRL. The health risk index for diazinon was highest for both eggplant and tomato samples, which may be due to its physiochemical properties. Fenitrothion and linuron are the two second most common types of pesticides detected in the vegetable samples. Regular monitoring of the use of common pesticides on vegetables should be conducted. Md. Nur Alam, M. Alamgir Zaman Chowdhury, M. Sabir Hossain, Mohammad Mijanur Rahman, M. Abdur Rahman, Siew Hua Gan, and Md. Ibrahim Khalil Copyright © 2015 Md. Nur Alam et al. All rights reserved. Chemical Composition, Antioxidant Potential, and Antibacterial Activity of Essential Oil Cones of Tunisian Cupressus sempervirens Thu, 01 Oct 2015 11:40:12 +0000 The extraction yield of the essential oil (EO) extracted by hydrodistillation from the cones of Tunisian Cupressus sempervirens L. was of 0.518%. The chemical composition was analyzed by GC-MS. Results showed that this essential oil was mainly composed of monoterpene hydrocarbons (65%) with α-pinene as the major constituent (47.51%). Its antioxidant activity was ascertained by evaluating the total antioxidant capacity and also by evaluating its inhibitory effect against DPPH and ABTS radicals. In addition, it showed a strong antioxidant power against the DPPH (IC50 = 151 µg/mL) and ABTS (IC50 = 176.454 µg/mL) radicals scavenging. Moreover, its antibacterial activity was tested against different species of pathogenic bacteria (three Gram-positive and eight Gram-negative bacteria). The bacterial strains susceptible to the evaluated oil were Bacillus subtilis, Escherichia coli, Klebsiella oxytoca, Morganella morganii, Shigella, and Vibrio cholerae. Aicha Ben Nouri, Wissal Dhifi, Sana Bellili, Hanene Ghazghazi, Chedia Aouadhi, Ameur Chérif, Mohamed Hammami, and Wissem Mnif Copyright © 2015 Aicha Ben Nouri et al. All rights reserved. Adsorptive Removal of Trichloroethylene in Water by Crop Residue Biochars Pyrolyzed at Contrasting Temperatures: Continuous Fixed-Bed Experiments Thu, 01 Oct 2015 11:31:38 +0000 Biochar (BC) has attracted great attention as an alternative sorbent to activated carbon (AC). Objective of this study was to determine trichloroethylene (TCE) removal by soybean stover BC pyrolyzed at 300 (BC300) and 700°C (BC700) in continuous fixed-bed column. Columns packed with BC300, BC700, and AC reached breakthrough time in 1.1, 27.0, and 50.7 h, respectively. BC700 had higher TCE adsorption capacity than BC300 due to its higher surface area, nonpolarity, and aromaticity. The sorption capacities of AC (774.0 mg g−1) and BC700 (515.1 mg g−1) were 21.6 and 14.4 times higher than that of BC300 (35.9 mg g−1). The lower desorption rate of TCE from BC300 than BC700 and AC may be attributed to the strong binding/partition of TCE to the noncarbonized part of BC. Thomas model also adequately described the adsorption data indicating interphase mass transfer. Overall, AC showed best efficiency for removing TCE from water in column experiments. However, although sorption and desorption capabilities of BC700 were a little lower than AC, it is still a good alternative for AC to remove organic contaminants such as TCE from water due to its cost-effectiveness. Ming Zhang, Mahtab Ahmad, Mohammad I. Al-Wabel, Meththika Vithanage, Anushka Upamali Rajapaksha, Hyuck Soo Kim, Sang Soo Lee, and Yong Sik Ok Copyright © 2015 Ming Zhang et al. All rights reserved. Nanofiltration in Transforming Surface Water into Healthy Water: Comparison with Reverse Osmosis Thu, 01 Oct 2015 11:29:19 +0000 The natural surface water, especially available through rivers, is the main source of healthy water for the living beings throughout the world from ancient days as it consists of all essential minerals. With the advent of industrialization, gradually even the most prominent rivers have been polluted in all parts of the world. Although there are lots of technologies, nanofiltration (NF) has been chosen to transform river water into healthy water due to its unique advantages of retaining optimum TDS (with essential minerals required for human body), consuming of lower energy, and no usage of any chemicals. The prominent parameters of surface water and macro/microminerals of treated water have been analyzed. It is shown that NF is better in producing healthy water with high flux by consuming low energy. L. D. Naidu, S. Saravanan, M. Chidambaram, Mukesh Goel, Ashutosh Das, and J. Sarat Chandra Babu Copyright © 2015 L. D. Naidu et al. All rights reserved. Rejection of Organic Micropollutants by Clean and Fouled Nanofiltration Membranes Thu, 01 Oct 2015 11:19:25 +0000 The rejection of organic micropollutants, including three polycyclic aromatic hydrocarbons (PAHs) and three phthalic acid esters (PAEs), by clean and fouled nanofiltration membranes was investigated in the present study. The rejection of organic micropollutants by clean NF90 membranes varied from 87.9 to more than 99.9%, while that of NF270 membranes ranged from 32.1 to 92.3%. Clear time-dependence was observed for the rejection of hydrophobic micropollutants, which was attributed to the adsorption of micropollutants on the membrane. Fouling with humic acid had a negligible influence on the rejection of organic micropollutants by NF90 membranes, while considerable effects were observed with NF270 membranes, which are significantly looser than NF90 membranes. The observed enhancement in the rejection of organic micropollutants by fouled NF270 membranes was attributed to pore blocking, which was a dominating fouling mechanism for loose NF membranes. Changes in the ionic strength (from 10 to 20 mM) reduced micropollutant rejection by both fouled NF membranes, especially for the rejection of dimethyl phthalate and diethyl phthalate by NF270 membranes (from 65.8 to 25.0% for dimethyl phthalate and 75.6 to 33.3% for diethyl phthalate). Lifang Zhu Copyright © 2015 Lifang Zhu. All rights reserved. Reduction of Phosphorus Pollution from Broilers Waste through Supplementation of Wheat Based Broilers Feed with Phytase Thu, 01 Oct 2015 11:07:09 +0000 The present study was conducted to reduce phosphorus pollution from broilers waste by supplementing phytase enzyme in broilers fee. Two hundred two-week-old broilers (Hubbard) were selected and randomly allocated to three dietary treatment groups, one control group (without phytase) and two trial groups (group A with 300 U/kg phytase and group B with 600 U/kg phytase). Each group was composed of 5 replicates with 10 chicks. Broilers fed the control diet (without phytase) gained weight slower (P < 0.05) than the other treatment groups. A significant increase in body weight gain of group A (28.00 ± 2.97) and group B (29.75 ± 3.45) was observed as compared to control group (26.75 ± 2.78). The feed intake of the birds fed the diets containing microbial phytase 600 U/kg was the highest. Phytase significantly (P > 0.05) reduces excreta P and Ca level. Phytase addition did not affect excreta pH. The presence of phytase in feed mixtures significantly (P > 0.05) improves the body weight gain and feed intake of broiler chickens. Ahmed Abdel-Megeed and Arifa Tahir Copyright © 2015 Ahmed Abdel-Megeed and Arifa Tahir. All rights reserved. Supercritical Algal Extracts: A Source of Biologically Active Compounds from Nature Thu, 01 Oct 2015 10:58:07 +0000 The paper discusses the potential applicability of the process of supercritical fluid extraction (SFE) in the production of algal extracts with the consideration of the process conditions and yields. State of the art in the research on solvent-free isolation of biologically active compounds from the biomass of algae was presented. Various aspects related with the properties of useful compounds found in cells of microalgae and macroalgae were discussed, including their potential applications as the natural components of plant protection products (biostimulants and bioregulators), dietary feed and food supplements, and pharmaceuticals. Analytical methods of determination of the natural compounds derived from algae were discussed. Algal extracts produced by SFE process enable obtaining a solvent-free concentrate of biologically active compounds; however, detailed economic analysis, as well as elaboration of products standardization procedures, is required in order to implement the products in the market. Izabela Michalak, Agnieszka Dmytryk, Piotr P. Wieczorek, Edward Rój, Bogusława Łęska, Bogusława Górka, Beata Messyasz, Jacek Lipok, Marcin Mikulewicz, Radosław Wilk, Grzegorz Schroeder, and Katarzyna Chojnacka Copyright © 2015 Izabela Michalak et al. All rights reserved. Relationship between Cadmium Fractions Obtained by Sequential Extraction of Soil and the Soil Properties in Contaminated and Uncontaminated Paddy Soils Thu, 01 Oct 2015 09:39:51 +0000 The method for the sequential extraction of cadmium from soil was adapted to investigate the relationship between different chemical forms of cadmium in soils and the soil properties of Cd-contaminated and uncontaminated paddy soils. Air-dried soil samples from each field site were sequentially fractionated into five forms: exchangeable Cd, inorganically bound Cd, organically bound Cd, oxide-occluded fraction, and residual Cd. The average and range of soil properties such as pH, total C, total N, CEC, exchangeable Ca, Mg, K, base saturation, available phosphate, particle size distribution, free iron oxide, oxalate extractable Al, and Fe were somewhat similar between uncontaminated and contaminated soils. The average total Cd in uncontaminated and contaminated soils was 0.26 and 0.65 mg kg−1, respectively. The proportions of soil Cd fractions did not differ between the uncontaminated and contaminated soils, although the Cd concentration of several fractions in contaminated soils was statistically higher than those in uncontaminated soils except for residual fraction. The proportion of exchangeable Cd was correlated with the CEC and phosphate absorption coefficient in contaminated soil but not in uncontaminated soil. Thus, soil properties appear to affect the proportions of soil Cd fractions in contaminated soil and should be considered when evaluating soil Cd mobility. Toshimitsu Honma, Hirotomo Ohba, Tomoyuki Makino, and Takuji Ohyama Copyright © 2015 Toshimitsu Honma et al. All rights reserved. Evaluation of Optimal Pore Size of (3-Aminopropyl)triethoxysilane Grafted MCM-41 for Improved CO2 Adsorption Thu, 01 Oct 2015 09:38:23 +0000 An array of new MCM-41 with substantially larger average pore diameters was synthesized through adding 1,3,5-trimethylbenzene (TMB) as the swelling agent to explore the effect of pore size on final adsorbent properties. The pore expanded MCM-41 was also grafted with (3-Aminopropyl)triethoxysilane (APTES) to determine the optimal pore size for CO2 adsorption. The pore-expanded mesoporous MCM-41s showed relatively less structural regularity but significant increments of pore diameter (4.64 to 7.50 nm); the fraction of mesopore volume also illustrated an increase. The adsorption heat values were correlated with the order of the adsorption capacities for pore expanded MCM-41s. After amine functionalization, the adsorption capacities and heat values showed a significant increase. APTES-grafted pore-expanded MCM-41s depicted a high potential for CO2 capture regardless of the major drawback of the high energy required for regeneration. Zhilin Liu, Yang Teng, and Kai Zhang Copyright © 2015 Zhilin Liu et al. All rights reserved. Inhibitory Effects of 4-(4-Methylbenzamino)benzoate on Adipocyte Differentiation Thu, 01 Oct 2015 09:33:30 +0000 The potent suppression of adipocyte differentiation by 4-(4-methylbenzamino)benzoate was discovered during the search for new antiobesity compounds. 4-(4-methylbenzamino)benzoate was observed to suppress adipocyte differentiation in 3T3-L1 cells by 96.8% at 50 μM without cytotoxicity. In addition, 4-(4-methylbenzamino)benzoate reduced the cellular expression of fatty acid synthase in a concentration-dependent manner, as well as suppressing PPAR-gamma activity, which controls fatty acid storage and glucose metabolism. Based on these results, 4-(4-methylbenzamino)benzoate shows potential as an antiobesity material. Jin Taek Hwang, Sanghee Kim, Bo-ra Yoon, Inwook Choi, and Sang Yoon Choi Copyright © 2015 Jin Taek Hwang et al. All rights reserved. Effect of Volatile Fatty Acid Concentration on Anaerobic Degradation Rate from Field Anaerobic Digestion Facilities Treating Food Waste Leachate in South Korea Thu, 01 Oct 2015 08:38:45 +0000 The purpose of this study was to investigate the effect of volatile fatty acid concentration on anaerobic degradation rate of food waste leachate in the anaerobic digestion facilities. The anaerobic digestion facilities treating food waste leachate (FWL), codigestion with food leachate and animal manure (A-MIX), and codigestion with food waste leachate and sewage sludge (S-MIX) were selected for this study. In accordance with the regulation under Wastes Control Act in South Korea, the guideline of volatile solid removal rate for anaerobic digestion facility is set as 65% for anaerobic degradation efficiency. Highest volatile solids removal rates were achieved from FWL (63.5%) than A-MIX (56.4%) and S-MIX (41.2%). Four out of eight FWLs met the guidelines. The concentration of volatile fatty acids, therefore, was analyzed to determine the relationship with volatile solid removal rate. The results showed that, in order to meet the Korean guideline of 65% volatile solid removal rate, volatile fatty acid concentrations should remain below 4,000 mg/L on the field anaerobic digestion facilities treating FWL. Volatile fatty acid concentrations should be used along with others as an operational parameter to control and manage the anaerobic digestion process. Dong-Jin Lee, Su-Young Lee, Ji-Su Bae, Jung-Gu Kang, Ki-Heon Kim, Sung-Su Rhee, Jong-Hwan Park, Ju-Sik Cho, Jin Chung, and Dong-Cheol Seo Copyright © 2015 Dong-Jin Lee et al. All rights reserved. First Evaluation of the Biologically Active Substances and Antioxidant Potential of Regrowth Velvet Antler by means of Multiple Biochemical Assays Thu, 01 Oct 2015 07:47:14 +0000 We investigated the biologically active substances contained in RVA (regrowth velvet antler) by comparing the composition of biologically active substances and antioxidant potential of different antler segments. RVA was subjected to extraction using DW (distilled water). RVA was divided into 3 segments: T-RVA (top RVA), M-RVA (middle RVA), and B-RVA (base RVA). The T-RVA section possessed the greatest amounts of uronic acid (36.251 mg/g), sulfated GAGs (sulfated glycosaminoglycans) (555.76 mg/g), sialic acid (111.276 mg/g), uridine (0.957 mg/g), uracil (1.084 mg/g), and hypoxanthine (1.2631 mg/g). In addition, the T-RVA section possessed the strongest antioxidant capacity as determined by DPPH, H2O2 (hydrogen peroxide), hydroxyl, and ABTS (2,2′-azinobis-3-ethylbenzthiazoline-6-sulphonate) radical scavenging activity as well as FRAP (ferric reducing antioxidant power) and ORAC (oxygen radical absorbance capacity). The values of those were 53.44, 23.09, 34.12, 60.31, and 35.81 TE/μM at 1 mg/mL and 113.57 TE/μM at 20 μg/mL. These results indicate that the T-RVA section possesses the greatest amount of biologically active substances and highest antioxidant potential. This is the first report on the biologically active substances and antioxidant potential of RVA. Yujiao Tang, Byong-Tae Jeon, Yanmei Wang, Eun-Ju Choi, Pyo-Jam Park, Hye-Jin Seong, Sang Ho Moon, and Eun-Kyung Kim Copyright © 2015 Yujiao Tang et al. All rights reserved. An Investigation of Fractal Characteristics of Marine Shales in the Southern China from Nitrogen Adsorption Data Thu, 01 Oct 2015 07:20:28 +0000 We mainly focus on the Permian, Lower Cambrian, Lower Silurian, and Upper Ordovician Formation; the fractal dimensions of marine shales in southern China were calculated using the FHH fractal model based on the low-pressure nitrogen adsorption analysis. The results show that the marine shales in southern China have the dual fractal characteristics. The fractal dimension at low relative pressure represents the pore surface fractal characteristics, whereas the fractal dimension at higher relative pressure describes the pore structure fractal characteristics. The fractal dimensions range from 2.0918 to 2.718 with a mean value of 2.4762, and the fractal dimensions range from 2.5842 to 2.9399 with a mean value of 2.8015. There are positive relationships between fractal dimension and specific surface area and total pore volume, whereas the fractal dimensions have negative correlation with average pore size. The larger the value of the fractal dimension is, the rougher the pore surface is, which could provide more adsorption sites, leading to higher adsorption capacity for gas. The larger the value of the fractal dimension is, the more complicated the pore structure is, resulting in the lower flow capacity for gas. Jian Xiong, Xiangjun Liu, and Lixi Liang Copyright © 2015 Jian Xiong et al. All rights reserved. Enhancement of Nutrient Removal in a Hybrid Constructed Wetland Utilizing an Electric Fan Air Blower with Renewable Energy of Solar and Wind Power Thu, 01 Oct 2015 05:50:43 +0000 The sewage treatment efficiency of hybrid constructed wetlands (CWs) was evaluated under different ventilation methods. The removal efficiencies of biochemical oxygen demand (BOD), total nitrogen (TN), and total phosphorus (TP) in the vertical flow- (VF-) horizontal flow (HF) CWs using an electric fan air blower by the renewable energy of solar and wind power were higher than those by natural ventilation, excluding only suspended solids (SS). The TN treatment efficiency in the CW using the air blower especially increased rapidly by 16.6% in comparison with the CW employing natural ventilation, since the VF bed provided suitable conditions (aerobic) for nitrification to occur. The average removal efficiencies of BOD, SS, TN, and TP in the effluent were 98.8, 97.4, 58.0, and 48.3% in the CW using an electric fan air blower, respectively. The treatment performance of the CWs under different ventilation methods was assessed, showing TN in the CW using an electric fan air blower to be reduced by 57.5~58.6% for inlet TN loading, whereas reduction by 19.0~53.3% was observed in the CW with natural ventilation. Therefore, to increase the removal of nutrients in CWs, an improved ventilation system, providing ventilation via an electric fan air blower with the renewable energy, is recommended. Dong Jin Lee, Se Won Kang, Jong Hwan Park, Seong Heon Kim, Ik Won Choi, Tae Hee Hwang, Byung Jin Lim, Soo Jung Jung, Ha Na Park, Ju Sik Cho, and Dong Cheol Seo Copyright © 2015 Dong Jin Lee et al. All rights reserved. Fast Atomic Charge Calculation for Implementation into a Polarizable Force Field and Application to an Ion Channel Protein Wed, 30 Sep 2015 11:04:30 +0000 Polarization of atoms plays a substantial role in molecular interactions. Class I and II force fields mostly calculate with fixed atomic charges which can cause inadequate descriptions for highly charged molecules, for example, ion channels or metalloproteins. Changes in charge distributions can be included into molecular mechanics calculations by various methods. Here, we present a very fast computational quantum mechanical method, the Bond Polarization Theory (BPT). Atomic charges are obtained via a charge calculation method that depend on the 3D structure of the system in a similar way as atomic charges of ab initio calculations. Different methods of population analysis and charge calculation methods and their dependence on the basis set were investigated. A refined parameterization yielded excellent correlation of . The method was implemented in the force field COSMOS-NMR and applied to the histidine-tryptophan-complex of the transmembrane domain of the M2 protein channel of influenza A virus. Our calculations show that moderate changes of side chain torsion angle and small variations of of Trp-41 are necessary to switch from the inactivated into the activated state; and a rough two-side jump model of His-37 is supported for proton gating in accordance with a flipping mechanism. Raiker Witter, Margit Möllhoff, Frank-Thomas Koch, and Ulrich Sternberg Copyright © 2015 Raiker Witter et al. All rights reserved. Simulation of Gas Transport in Tight/Shale Gas Reservoirs by a Multicomponent Model Based on PEBI Grid Tue, 29 Sep 2015 11:23:50 +0000 The ultra-low permeability and nanosize pores of tight/shale gas reservoir would lead to non-Darcy flow including slip flow, transition flow, and free molecular flow, which cannot be described by traditional Darcy’s law. The organic content often adsorbs some gas content, while the adsorbed amount for different gas species is different. Based on these facts, we develop a new compositional model based on unstructured PEBI (perpendicular bisection) grid, which is able to characterize non-Darcy flow including slip flow, transition flow, and free molecular flow and the multicomponent adsorption in tight/shale gas reservoirs. With the proposed model, we study the effect of non-Darcy flow, length of the hydraulic fracture, and initial gas composition on gas production. The results show both non-Darcy flow and fracture length have significant influence on gas production. Ignoring non-Darcy flow would underestimate 67% cumulative gas production in lower permeable gas reservoirs. Gas production increases with fracture length. In lower permeable reservoirs, gas production increases almost linearly with the hydraulic fracture length. However, in higher permeable reservoirs, the increment of the former gradually decreases with the increase in the latter. The results also show that the presence of CO2 in the formation would lower down gas production. Longjun Zhang, Daolun Li, Lei Wang, and Detang Lu Copyright © 2015 Longjun Zhang et al. All rights reserved. Experimental Investigation of Flow Resistance in a Coal Mine Ventilation Air Methane Preheated Catalytic Oxidation Reactor Tue, 29 Sep 2015 06:30:36 +0000 This paper reports the results of experimental investigation of flow resistance in a coal mine ventilation air methane preheated catalytic oxidation reactor. The experimental system was installed at the Energy Research Institute of Shandong University of Technology. The system has been used to investigate the effects of flow rate (200 Nm3/h to 1000 Nm3/h) and catalytic oxidation bed average temperature (20°C to 560°C) within the preheated catalytic oxidation reactor. The pressure drop and resistance proportion of catalytic oxidation bed, the heat exchanger preheating section, and the heat exchanger flue gas section were measured. In addition, based on a large number of experimental data, the empirical equations of flow resistance are obtained by the least square method. It can also be used in deriving much needed data for preheated catalytic oxidation designs when employed in industry. Bin Zheng, Yongqi Liu, Ruixiang Liu, Jian Meng, and Mingming Mao Copyright © 2015 Bin Zheng et al. All rights reserved. Amidine Sulfonamides and Benzene Sulfonamides: Synthesis and Their Biological Evaluation Mon, 28 Sep 2015 13:53:16 +0000 New amidine and benzene sulfonamide derivatives were developed and structures of the new products were confirmed by elemental and spectral analysis (FT-IR, ESI-MS, 1HNMR, and 13CNMR). In vitro, developed compounds were screened for their antibacterial and antifungal activities against medically important bacterial strains, namely, S. aureus, B. subtilis, and E. coli, and fungi, namely, A. flavus, A. parasiticus, and A. sp. The antibacterial and antifungal activities have been determined by measuring MIC values (μg/mL) and zone of inhibitions (mm). Among the tested compounds, it was found that compounds 3b, 9a, and 9b have most potent activity against S. aureus, A. flavus, and A. parasiticus, respectively, and were found to be more active than sulfamethoxazole and itraconazole with MIC values 40 μg/mL. In contrast, all the compounds were totally inactive against the A. sp. except 10b and 15b to show activity to some extent. Muhammad Abdul Qadir, Mahmood Ahmed, Hina Aslam, Sadia Waseem, and Muhammad Imtiaz Shafiq Copyright © 2015 Muhammad Abdul Qadir et al. All rights reserved. Effect of Matrix-Wellbore Flow and Porosity on Pressure Transient Response in Shale Formation Modeling by Dual Porosity and Dual Permeability System Mon, 28 Sep 2015 06:57:34 +0000 A mathematical dual porosity and dual permeability numerical model based on perpendicular bisection (PEBI) grid is developed to describe gas flow behaviors in shale-gas reservoirs by incorporating slippage corrected permeability and adsorbed gas effect. Parametric studies are conducted for a horizontal well with multiple infinite conductivity hydraulic fractures in shale-gas reservoir to investigate effect of matrix-wellbore flow, natural fracture porosity, and matrix porosity. We find that the ratio of fracture permeability to matrix permeability approximately decides the bottom hole pressure (BHP) error caused by omitting the flow between matrix and wellbore and that the effect of matrix porosity on BHP is related to adsorption gas content. When adsorbed gas accounts for large proportion of the total gas storage in shale formation, matrix porosity only has a very small effect on BHP. Otherwise, it has obvious influence. This paper can help us understand the complex pressure transient response due to existence of the adsorbed gas and help petroleum engineers to interpret the field data better. Daolun Li, Wenshu Zha, Dewen Zheng, Longjun Zhang, and Detang Lu Copyright © 2015 Daolun Li et al. All rights reserved. Laboratory Measurement and Interpretation of the Changes of Physical Properties after Heat Treatment in Tight Porous Media Sun, 27 Sep 2015 14:16:57 +0000 Prevention of water blocking and optimization of multiscale flow channels will increase gas production of tight reservoirs. Physical properties of samples from representative tight gas reservoirs were measured before and after high temperature treatment. Results show that, with the increase of treatment temperature, mass decreases, acoustic transit time increases, and permeability and porosity increase. Permeability begins to increase dramatically if treatment temperature exceeds the threshold value of thermal fracturing, which is 600~700°C, 500~600°C, 300~500°C, and 300~400°C for shale, mudstone, tight sandstone, and tight carbonate rock, respectively. Comprehensive analyses indicate that the mechanisms of heat treatment on tight porous media include evaporation and dehydration of water, change of mineral structure, generation of microfracture, and network connectivity. Meanwhile, field implementation is reviewed and prospected. Interpretations indicate that, according to the characteristics of multiscale mass transfer in tight gas formation, combining heat treatment with conventional stimulation methods can achieve the best stimulation result. Yili Kang, Mingjun Chen, Lijun You, and Xiangchen Li Copyright © 2015 Yili Kang et al. All rights reserved. Stability of Fluorosurfactant Adsorption on Mineral Surface for Water Removal in Tight Gas Reservoirs Sun, 27 Sep 2015 13:40:14 +0000 Long-term effectiveness of rock wettability alteration for water removal during gas production from tight reservoir depends on the surfactant adsorption on the pore surface of a reservoir. This paper selected typical cationic fluorosurfactant FW-134 as an example and took advantage of Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and atomic force microscope (AFM) to investigate its adsorption stability on the rock mineral surface under the oscillation condition at high temperature for a long time. The experimental results indicate that the F element content on the sample surface increases obviously, the surface structure of fluorine-carbonization also undergoes a significant change, and the fluorine surfactant exhibits a good interfacial modification and wettability alteration ability due to its adsorption on the pore surface transforming the chemical structure of the original surface. The adsorption increases indistinctly with the concentration of over 0.05% due to a single layer adsorption structure and is mainly electrostatic adsorption because the chemical bonding between the fluorosurfactant and the rock mineral surface, the hydrogen bonding, is weak and inconspicuous. Lijun You, Wanchun Zhang, Yili Kang, Zhangxin Chen, and Xuefen Liu Copyright © 2015 Lijun You et al. All rights reserved. Finite Element Method Using a Characteristic-Based Split for Numerical Simulation of a Carbonate Fracture-Cave Reservoir Sun, 27 Sep 2015 13:16:56 +0000 Fracture-cave carbonate reservoirs occur widely in source rocks and are prospects for exploitation worldwide. However, the presence of massive caves and multiscale fracture systems results in extremely complex fluid flow patterns. Therefore, in this paper, a discrete network model for fracture-cave reservoirs was established to study fluid flow characteristics and pressure distributions in complex flow regimes. In this study, the cave system was treated as a free-flow region, and the fluid flow in fracture systems followed the Navier-Stokes and Darcy equations, respectively. After discrete modeling, the Galerkin finite element method was used for numerical calculation of the single-phase free flow; the method maintains a high-precision result with low grid orientations during the simulation. In addition, because only one linear equation requires solving at each step, the solution is obtained quickly. Moreover, based on the proposed discrete media network model of fracture-cave reservoirs and the finite element numerical calculation method, a corresponding simulator was also developed. The finite element numerical simulation method based on the characteristic-based split (CBS) algorithm has proven to be applicable to complex flow problems in fracture-cave reservoirs. Liehui Zhang, Yuhui Zhou, Lei Zhao, and Deliang Zhang Copyright © 2015 Liehui Zhang et al. All rights reserved. Compositional Modeling for Optimum Design of Water-Alternating CO2-LPG EOR under Complicated Wettability Conditions Sun, 27 Sep 2015 13:07:04 +0000 The addition of LPG to the CO2 stream leads to minimum miscible pressure (MMP) reduction that causes more oil swelling and interfacial tension reduction compared to CO2 EOR, resulting in improved oil recovery. Numerical study based on compositional simulation has been performed to examine the injectivity efficiency and transport behavior of water-alternating CO2-LPG EOR. Based on oil, CO2, and LPG prices, optimum LPG concentration and composition were designed for different wettability conditions. Results from this study indicate how injected LPG mole fraction and butane content in LPG affect lowering of interfacial tension. Interfacial tension reduction by supplement of LPG components leads to miscible condition causing more enhanced oil recovery. The maximum enhancement of oil recovery for oil-wet reservoir is 50% which is greater than 22% for water-wet reservoir. According to the result of net present value (NPV) analysis at designated oil, CO2, propane, and butane prices, the optimal injected LPG mole fraction and composition exist for maximum NPV. At the case of maximum NPV for oil-wet reservoir, the LPG fraction is about 25% in which compositions of propane and butane are 37% and 63%, respectively. For water-wet reservoir, the LPG fraction is 20% and compositions of propane and butane are 0% and 100%. Jinhyung Cho, Sung Soo Park, Moon Sik Jeong, and Kun Sang Lee Copyright © 2015 Jinhyung Cho et al. All rights reserved.