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In this study, we report a successful strategy for the generation of palladium nanoparticles on porous P-doped carbon spheres with a high surface area. The synthesized Pd/P-CS was used in the CO2 fixation reaction with various epoxides under solvent-free conditions. The prepared Pd0/P-CS nanocatalyst was affirmed by different analysis, including TEM, FE-SEM, EDS, BET, FT-IR, XRD, and ICP-OES. The aforesaid nanocatalyst with a unique porous structure was an outstanding catalytic performance on different substrates toward produce of cyclic carbonates under solvent-free condition with high yields of final products. The catalytic activity of Pd0/P-Cs could be maintained efficiently after recycling up to five consecutive runs under the optimized reaction conditions. [ABSTRACT FROM AUTHOR]

This study investigated mathematical modeling and optimization of the xylene isomerization reaction in a commercial adiabatic reactor. The proposed model, consisting of a set of algebraic and ordinary differential equations, is based on a heterogeneous one‐dimensional steady‐state formulation. To verify the proposed model, the simulation results have been compared to available data from an industrial reactor. A good agreement has been found between the simulation and plant data. The genetic algorithm (GA) method is applied to optimize the reactor operating conditions considering the para‐xylene (p‐xylene) mole fraction in reactor outlet as the main objective function. According to the simulation results, there is an optimum initial temperature for maximizing the objective function. In the optimization process, the p‐xylene mole fraction was enhanced by 3.0% at an optimized feed temperature of 678.04K. [ABSTRACT FROM AUTHOR]

Nano‐catalyst of cobalt‐vanadate (Co‐V/Al2O3, supported on alumina) application in Fischer–Tropsch process (FT) was explored in a various conversions of synthesis gas. The catalyst characterization was performed using different methods including Brunauer–Emmett–Teller (BET) surface area, X‐ray fluorescence (XRF), X‐ray diffraction (XRD), Temperature programmed reduction (TPR) profile, and Transmission electron microscopy (TEM). Due to the extreme complexity and nonlinearity of catalytic processes, adaptive network based fuzzy interface system (ANFIS) was developed as a predictive tool for evaluation of Co‐V/Al2O3 nano‐catalyst performance in FT process. Input vector included reaction condition such as, pressure, temperature, time, and CO/H2 ratio of different experiments while the outputs were composition of CO, CO2, and CH4. The proposed model was used for optimization of the process, also the optimal operating conditions were acquired using particle swarm optimization (PSO). The performance of the algorithms and the quality of the solutions were measured by introducing the optimal operating conditions to obtained model. Comparative studies and results analysis were then conducted on the optimization results. The model result shows a good consistency with experimental observations. [ABSTRACT FROM AUTHOR]

In this paper, the structure of Al2O3 is modified with magnesium to synthesize MgAl2O4 as an oxygen carrier (OC) support. The surface properties and structural stability of the modified support are improved by the incorporation of magnesium in the structure of the support and additionally by narrowing the pore size distribution (about 2.3 nm). Then, iron oxide is impregnated on both an Al2O3 support and a MgAl2O4 support as the oxygen transfer active site. The XRD results showed the formation of solely Fe2O3 on the MgAl2O4 support, while both Fe2O3 and Fe3O4 are detected in the synthesized Fe2O3-Al2O3 structure. The synthesized samples are investigated in chemical looping cycles, including CO reduction (as one of the most important side reactions of chemical looping reforming), at different temperatures (300-500 °C) and oxidation with steam at 700 °C for hydrogen production. The obtained results showed the inhibition of Fe-Al spinel formation in the structure of the Fe2O3-MgAl2O4 OC. In addition, H2 with a purity higher than 98% is achievable in oxidation of the OC with steam. In addition, the activity and crystalline change of the Fe2O3-MgAl2O4 OC is investigated after 20 reduction-oxidation cycles. [ABSTRACT FROM AUTHOR]

Hydrogen, as a clean energy carrier, could be produced aided by cyclic oxidation-reduction of oxygen carriers (OCs) in contact with carbonaceous fuel in chemical looping steam methane reforming (CL-SMR) process. In this study, the cerium was incorporated into the SBA-16 support structure to synthesize the Ni/Ce-SBA-16 OC. The supports were synthesized using hydrothermal method followed by impregnation of Ni and characterized via low and wide angle X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), coupled with energy dispersive X-ray (EDX) spectroscopy, and transmission electron micrograph (TEM) techniques. In addition, the effect of various Si/Ce molar ratios (20-60) in the support structure, Ni loading (10-30 wt %), reaction temperature (500-750 °C), and life time of optimal oxygen carrier over 16 cycles were investigated. The results of wide angle XRD and SEM revealed that the incorporation of CeO2 in the channels of SBA-16 caused the formation of nickel metallic particles with smaller size and prevents the coke formation. The results showed that OC with 15 wt % Ni and Si/Ce molar ratio of 40 (15Ni/Ce-SBA-16(40)) has the best performance when compared with other OCs in terms of catalytic activity and structural properties. The methane conversion of about 99.7% was achieved at 700 °C using 15Ni/Ce-SBA-16(40) OC. We anticipate that the strategy can be extended to investigate a variety of novel modified mesoporous silica as the supporting material for the Ni based OCs. [ABSTRACT FROM AUTHOR]

In this work, the modification of Ni/SBA-16 oxygen carrier (OC) with yttrium promoter is investigated. The yttrium promoted Ni-based oxygen carrier was synthesized via co-impregnation method and applied in chemical looping steam methane reforming (CL-SMR) process, which is used for the production of clean energy carrier. The reaction temperature (500-750 °C), Y loading (2.5-7.4 wt. %), steam/carbon molar ratio (1-5), Ni loading (10-30 wt. %) and life time of OCs over 16 cycles at 650 °C were studied to investigate and optimize the structure of OC and process temperature with maximizing average methane conversion and hydrogen production yield. The synthesized OCs were characterized by multiples techniques. The results of X-ray powder diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX) of reacted OCs showed that the presence of Y particles on the surface of OCs reduces the coke formation. The smaller NiO species were found for the yttrium promoted OC and therefore the distribution of Ni particles was improved. The reduction-oxidation (redox) results revealed that 25Ni-2.5Y/SBA-16 OC has the highest catalytic activity of about 99.83% average CH4 conversion and 85.34% H2 production yield at reduction temperature of 650 °C with the steam to carbon molar ratio of 2. [ABSTRACT FROM AUTHOR]

In this study, the application of a calcium-based bifunctional catalyst/sorbent is investigated in modified chemical looping steam methane reforming (CLSMR) process for in situ CO2 sorption and H2 production. The yttrium promoted Ca-Co samples were synthesized and applied as bifunctional catalysts/sorbent. The influence of reduction temperature (500-750 °C), Ca/Co and Ca/Y ratios (1.5-∞ and 3-18, respectively) and catalyst life time are determined in CLSMR process. The physicochemical transformation of fresh, used and regenerated samples after 16 redox cycles are determined using X-ray powder diffraction (XRD), N2 adsorption-desorption, field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM) techniques. The effect of yttrium promoter on the structure of catalyst and regeneration step on the reversibility of bifunctional catalyst/sorbent was two important factors. The characterization results revealed that the presence of yttrium in the structure of Ca-9Co sample could improve the morphology and textural properties of catalyst/sorbents. The suitable reversibility of bifunctional catalyst/sorbents during the repeated cycles is confirmed by characterization of calcined samples. The Ca-9Co-4.5Y as optimal catalyst illustrated superior performance and stability. It showed about 95.8% methane conversion and 82.9% hydrogen yield at 700 °C and stable activity during 16 redox cycles. [ABSTRACT FROM AUTHOR]

Background: Group B streptococcus colonization in pregnant women usually has no symptoms, but it is one of the major factors of newborn infection in developed countries. In Iran, there is a little information about the prevalence of maternal colonization and newborns infected by group B streptococcus. In order to find the necessary information to create a protocol for prevention and treatment of group B streptococcus infection in newborns, we conducted a study of its prevalence among Iranian pregnant women and its vertical transmission to their newborns. Materials and Methods: This is a cross-sectional descriptive and analytic study performed at Prenatal Care Clinic of the Sarem Hospital from 2009 to 2011. The pregnant women with the gestational age of 35-37 weeks were enrolled in the study. The vaginal culture for group B streptococcus was done for 980 mothers based on our protocol. Among 980 mothers, 48 were shown positive vaginal culture; however, 8 cases among these 48 mothers were positive for both vaginal and urine culture. Babies with mothers showing positive vaginal culture were screened for infection using complete blood count /blood culture (B/C) and C-reactive protein (CRP). Then, a complete sepsis workup was performed for babies with any signs of infection in the first 48 hours after birth, and they received antibiotic therapy if necessary. All collected data were analyzed (SPSS version 15). Results: Among 980 pregnant women with vaginal culture, 48 cases had positive group B streptococcus cultures among which 8 mothers also had positive group B streptococcus urine culture. Our findings revealed that 22 (50%) symptomatic neonates were born from the mothers with positive vaginal culture for group B streptococcus. About 28 of them (63%) had absolute neutrophil count more than normal, and 4 (9.1 %) newborns were omitted from the study. Therefore, 50% of neonates showed clinical feature, whereas para-clinical test was required to detect the infection for the rest of neonates who showed no signs or symptoms. Conclusion: The colonization of group B streptococcus in Iranian women is significant, while 50% of newborns from mother with positive vaginal culture were symptomatic after birth; therefore, screening of newborns for group B streptococcus infection is recommended to become a routine practice in all healthcare centers in Iran. [ABSTRACT FROM AUTHOR]

For the first time, a multi-objective optimization approach is used to optimize energy efficiency with other conflicting objectives for tri-reforming of methane. A 2-D axisymmetric model over nickel based catalysts is established to maximize the energy efficiency, syngas production and CO 2 conversion. The inlet temperature, oxygen/methane and carbon dioxide/methane are considered as the decision variables. The attained results revealed that at the utopia point for maximization of H 2 /CO ratio and energy efficiency, not only H 2 /CO ratio and energy efficiency reach 2.76 and 42.21, but also CH 4 consumption overtakes 60%. Besides, when we consider maximization of CO 2 conversion and energy efficiency as the objectives, 1% compromise in the best value of energy efficiency results in an increment of 40% in the value of CO 2 conversion. Finally, the third optimization reveals that the CH 4 conversion is above 80% and the final mole fraction of H 2 is approximately 0.15. [Display omitted] • Three two-objective optimization problems for a tri-reforming reactor. • Energy, mass and momentum study of methane tri-reforming in a reactor. • Maximization of syngas production, energy efficiency and CO 2 conversion. • Considering three decision variables consisting of the inlet temperature, oxygen/methane and carbon dioxide/methane. • Study of five important points of the Pareto solutions. [ABSTRACT FROM AUTHOR]

Microthrombi formation and hemolytic anemia are signs of hemolytic-uremic syndrome (HUS) that result from platelet consumption and red blood cell (RBC) destruction due to vascular damage. HUS manifests as a triad of signs: micro-angiopathic hemolytic anemia, throm-bocytopenia, and uremia. Prenatal asphyxia (PA) also leads to renal insufficiency and vascular damage. There is an overlap between the clinical presentation of PA and neonatal atypical HUS. We have reported the case of a neonate with a primary diagnosis of PA and clinical presentation of acute renal failure (ARF), anemia (Hb = 10 g/dl) and thrombocytopenia (Pit = 80000). His APGAR scores were 1 (1 minute), 3 (5 minutes), and 7 (10 minutes). A peripheral blood smear (PBS) was performed, which contained schistocytes (32%) with helmet and burr cells. The neonate's cord blood gas values were: pH of 7.07, HC03 = 11mmol/L, and C02 = 57mmHg. The first two days of life, he was anuric with elevated BUN and Cr (2.1mg/dL) levels. Complement (C3) was within normal limits at 0.65 g/L (0.89 - 1.87 g/L), however C4 was below the lower limit of normal at 0.14 g/L (0.16 - 0.38 g/L). We ruled out other causes of PA such as maternal illness, placenta abnormalities and infections (TORCH). We hypothesized that atypical neonatal HUS can progress to PA because of the presence of severe anemia and microthrombi formation. [ABSTRACT FROM AUTHOR]