Post-functionalization of polymeric mesoporous C@Zn coreeshell spheres used for methyl ester production

In the present study, the mesoporous carbon@zinc (C@Zn) core-shell spheres were hydrothermally synthesized, using polyethylene glycol (PEG) as the surfactant and d-glucose as the pore forming agent. Then, the post-sulfonation treatment was carried out to prepare polymeric mesoporous SO3H-ZnO catalyst. The physicochemical, structural, textural and morphological properties of the synthesized catalysts were characterized by X-ray powder diffraction (XRPD), surface area analysis (Brunauer–Emmett–Teller equation), temperature programed desorption (TPD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The polymeric mesoporous SO3H-ZnO catalyst owned a high surface area of 396.56 m2/g with the average pore size of 3.45 nm and acid strength of 1.92 ± 0.05 mmol/g. The catalytic activity of the synthesized catalyst was further studied via esterification of the palm fatty acid distillate (PFAD), using a microwave-assisted technique. The biodiesel yield of 91.20% was achieved under the optimized esterification conditions as follows: the methanol to PFAD molar ratio of 9:1, catalyst concentration of 1.5 wt%, reaction temperature of 90 °C and reaction time of 15 min. The spent mesoporous catalyst was highly stable for reuse with nine continuous runs without further treatment

Fundamentals and recent progress relating to the fabrication, functionalization and characterization of mesostructured materials using diverse synthetic methodologies

Since 1990 and the invention of the very first generation of ordered mesoporous silica materials, several innovative methodologies have been applied to synthesize, characterize, and modify silica/non-silica mesoporous materials. The growth of the mesoporous materials field has generated significant environmental and economic advantages compared to various other industrial developments. According to the literature, there are several key synthesis approaches and parameters that can affect the structural, textural and morphological characteristics of mesoporous materials. To date, huge attempts have been made to maximize the activities and selectivities of these materials through either the in situ or post-synthesis functionalization of the large interior surface areas and internal mesostructured frameworks in the presence of specific organic/inorganic components. However, the main challenge is to provide good control over the incorporation and distribution of multiple guest components within the mesostructured hosts. Mesostructured materials have received great attention for various applications, such as being used in electronics, medicine, photocatalysis, catalyst supports, catalysis, absorbers, sensors, gas separation, etc. In the current paper, several recent developments have been highlighted and reviewed regarding the fabrication and characterization of siliceous/non-siliceous mesoporous materials via various synthetic approaches. Furthermore, the availability of diverse functionalization methods has been reviewed to provide comprehensive approaches for synthesizing new generations of suitably modified mesoporous materials with superior structural, physicochemical, and textural characteristics

Developing strategies to retain organizational insurers using a clustering technique: evidence from the insurance industry

Formulating strategies to maintain policyholders is one of the main challenges for most insurance companies in Iran. The purpose of this article is to help marketing strategists of insurance companies predict insurees' churn and develop insurees retention strategies. Since the cost of maintaining an insurance policyholder is approximately one-eighth of the cost of attracting new ones, predicting their churn can help insurance companies adopt proper strategies in advance, which will definitely lead to saving marketing costs and maintaining the insurer's portfolio. Accordingly, the main question of this research is how to classify organizational insurees with the help of the clustering technique. This research is conducted in both qualitative and quantitative phases. In the qualitative phase, by conducting a semi-structured interview (interview protocol) with 15 experts in the insurance industry, the influential factors on policyholders' churn are identified. Then, based on the factors identified in the research literature and comparing them with the interview results, eight main factors are finalized. In the quantitative phase, in order to cluster the organizational insurees, 120 samples from the Iran Insurance Company are selected, and k-means is applied for clustering. Organizational insurees are divided into two groups according to the desired indicators. Using the results of clustering, insurees are divided into four groups, and effective marketing strategies are developed for each group. According to the results, the variable “health care insurance price” has the most effective role in separating the clusters at an error level of <0.01, and on the contrary, the variable “liability insurance amount” has the least important role at an error level of <0.978

Effects of symbiotic and vitamin E supplementation on blood pressure, nitric oxide and inflammatory factors in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) has been suggested to be well correlated with altered blood pressure. This study was conducted to determine the effects of symbiotic and vitamin E supplementation on blood pressure and inflammatory indices of patients with NAFLD. This randomized, double-blind, placebo-controlled trial was performed among 60 NAFLD patients aged 25 to 64 years old. Participants were randomly divided into four groups to receive a 400 IU alpha-tocopherol and 2 × 108 CFU/g symbiotic supplement for 8 weeks. The anthropometric parameters, systolic blood pressure (SBP) and diastolic blood pressure (DBP), serum malondialdehyde (MDA), nitric oxide (NO) and tumor necrosis factor α (TNFα) were assessed at baseline and after 8 weeks of intervention. After 8 weeks of intervention, combined symbiotic and alpha-tocopherol, symbiotic and alpha-tocopherol lone administration, compared with the placebo, resulted in significant decreases in SBP (-17.07±2.1, -16.07±3.56, -1.73±2.25 and -1.55±3.01 mmHg, P=0.01), serum MDA (-1.19±0.5, -0.12±0.65, 0.14 ± 0.64 and 0.16±0.34 nmol/mL, P<0.001), serum TNFα (-15.62±13.93, -9.24±7.12, -11.44 ± 15.47 and 3.01±1.71 pg/ml, P<0.001) concentrations. A significant decrease in serum AST (-11.36±4.52, -7.43±8.58, -5.93±6.61 and 2.5±5.75 μmol/L, P <0.001), ALT (-12.79±3.65, -3.66±6.81, -6.54±7.66 and 4.16±3.43 μmol/L, P <0.001) and ALP (-26.8±11.1, -4.56±9.22, -14.48±12.22 and 5.19±2.64 μmol/L, P <0.001) was seen. Variations in DBP and serum NO concentration were not significant. Alpha-tocopherol and symbiotic supplementation among patients with NAFLD resulted in decreased SBP, serum MDA, TNFα levels and enzymes liver; however, they did not affect DBP and serum NO concentration

Study the effect of various wash-coated metal oxides over synthesized carbon nanofibers coated monolith substrates

In this research work, carbon nanofibers (CNFs) were synthesized on honeycomb monolith substrates using injection chemical vapor deposition (ICVD) technique. The effect of various wash-coated materials and catalyst promoter on the growth rate of CNFs on monolith substrates were examined. The characteristics of the synthesized CNFs-coated monolith composites were examined using Raman spectroscopy, Brunauer-Emmett-Teller (BET), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FE-SEM), and Transmission electron microscopy (TEM) techniques. According to the textural characterization study, the specific surface area and pore volume of CNFs-coated monolith composites were significantly improved as compared to bare monolith which might be attributed to the growth of highly pure and aligned CNFs over monolith substrate. Besides that, the synthesized CNFs-coated monolith possessed extremely well thermal stability up to the temperature of 550 °C which was corresponded to the strong attachment of highly graphitized CNFs over monolith substrates

Kinetic study of Fenton-like degradation of Methylene blue in Aqueous solution using calcium peroxide

The textile industry is one of the fastest-growing industries that significantly contribute to the economic growth in Malaysia. Dyeing wastewater is one of the more difficult to control in industrial wastewater. Methylene blue is a widely used dye in the textile industry, which cannot be discharged directly into the natural environment without treatment. The present study involves the degradation of methylene blue by a Fenton-like system using calcium peroxide (CaO2, CP). The process of degradation was recorded spectrophotometrically. The field emission scanning electron microscope (FESEM) and energy dispersive X-ray (EDX) were measured for testing the purchased commercial calcium peroxide. The effect of pH, the initial dosage of CaO2, and temperatures were studied with kinetics modeling, respectively. The results indicated that 97.07% removal of methylene blue took place at the optimum condition (pH=3.0, initial CaO2 dosage=3.0 g, 65°C, 150 rpm, contact time=60 minutes). Over four models (zero-order, first-order, second-order, Behnajady, Modirshahla, and Ghanbary (BMG) model) applied in this study, the BMG model with the R2 =0.9935 was in accordance with the experimental data

Sulfonated polymeric zinc oxide-based nanocatalysts for methyl ester production

The increasing production growth and economic developments have increased not only the consumption of energy but also increased the level of pollutants. It is assumed that fossil fuels would be eliminated in years to come, which alerted an urgent need to switch to the renewable energy sources (RESs). In this research work, high free fatty acid feedstock, palm fatty acid distillate (PFAD), has been explored as non-edible feedstock for biodiesel production using efficient mesoporous zinc oxide (ZnO) based nanocatalysts. The main purpose was to develop the mesoporous ZnO based catalysts to enhance the conversion rate of biodiesel production for PFAD. An efficient mesoporous ZnO based nanocatalysts were hydrothermally fabricated, using the polyethylen glycol (PEG) as a surfactant and D-glucose as a template. The effects of different zinc nitrate concentration and different calcination temperature were determined on the structural and textural properties. Surface functionalization is a beneficial approach which improves the adsorption capacity and surface activity of the parent materials. One route is the doping of the metal nanoparticles as support into pre-fabricated materials. In this project, ZnO has been functionalized with Al and Cu in order to improve its textural properties. Zinc aluminate (ZnAl2O4) and zinc-cupper (CuO-ZnO) mixed metal oxides possess superior advantages such as high surface area and high thermal stability. Post-sulfonation treatment is another approach which was done in order to modify the hydrophobicity via attaching of ─SO3H groups on the active sites. Furthermore, the effect of sulfonation conditions on catalytic activity was also examined. It was observed that sulfonation under severe conditions led to the reduction of the textural properties. The palm fatty acid distillate (PFAD) was chosen as feedstock for biodiesel production, containing high FFA (around 80-90%). In order to improve the esterification process for PFAD production, a comparison study was also carried out between two efficient autoclave and microwave heating systems over synthesized mesoporous ZnO based nanocatalysts. The influences of esterification reaction conditions (methanol to oil molar ratio, catalyst concentration, reaction temperature and reaction time) towards the catalytic performance of the synthesized nanocatalysts were also investigated to optimize the higher biodiesel yield. It was found that the functionalized mesoporous ZnO based SO3H-ZnO, SO3H-ZnAl2O4, SO3H-CuO-ZnO nanocatalysts had high catalytic activity for esterifying PFAD, giving FAME yield of 91.20%, 94.65%, and 95.76%, respectively. The recyclability of the synthesized catalysts was further evaluated. According to the recyclability results, the mesoporous ZnO based nanocatalysts were able to remain active for at least eight consecutive runs without using further treatment. Furthermore, the physico-chemical characteristics of the biodiesel produced from PFAD were tested with compliance to EN14214 and ASTM D6751 standards. The key fuel properties of the produced PFAD biodiesel were all within range of the mentioned standards. As a conclusion, from all the results, it was found that the synthesized sulfonated mesoporous ZnO based nanocatalysts had great potential to catalyze high FFA feedstock (PFAD) for biodiesel production with high recyclability. The excellent activity and recyclability of the catalyst may be assigned to the combination of unique textural properties and polymeric attachment of the ─SO3H functional group to the surface of the catalyst. The esterification reaction under solvo-thermal methods resulted in high biodiesel yield in shorter reaction rate, especially using microwave heating system

Q-switched erbium-doped fiber laser with molybdenum disulfide (MoS2) nanoparticles on D-shaped fiber as saturable absorber

In this study, short Q-switching laser pulses are generated by drop-casting two-dimensional Molybdenum Disulfide (MoS2) nanoparticles as saturable absorbers (SA) on a side polished optical fiber in a C-band laser cavity. The proposed laser is capable of generating highly stable Q-switched laser pulses at the wavelength of 1559.42nm with a maximum repetition rate of 73.96kHz, and a minimum pulse width of 1.93μs. The relatively high signal-to-noise ratio of 58.7dB indicates a highly stable output. The proposed SA can be applied in a variety of fields due to its ease of manufacturing and cost-effectiveness as well as its robust and compact design. © 2019 World Scientific Publishing Company

Computer simulation of a novel pharmaceutical silicon nanocarrier

Saeed Soltani, Soroush Sardari, Sima Azadi SororDrug Design and Bioinformatics Unit, Medical Biotechnology Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, IranAbstract: We show the potential of the nanosilicon structure of the frustules of a typical diatom, Cymatopleura sp., as a new vehicle for drugs. The basic diatom nanostructure is a lattice of SiO2, and computerized methods in a dock project have identified the most likely and the best drug types to load into such a structure.Keywords: diatom, docking, artificial neural network, simulation, computerized method