Low Methanol Concentrations Research Articles

A superhydrophobic bromomethylated poly(phenylene oxide) as a multifunctional polymer filler in SPEEK membrane towards neat methanol operation of direct methanol fuel cells

Development of novel proton exchange membrane (PEM) with the aim toward neat methanol operation of direct methanol fuel cell (DMFC) has attracted increasing attention. Proton exchange membrane technology with remarkably low methanol permeability has been considered as one of the most facile ways to approach this target. Here, sulfonated poly(ether ether ketone) (SPEEK) membrane was modified by blending with superhydrophobic bromomethylated poly(phenylene oxide) (BPPO). The fabricated SPEEK/BPPO membranes possess obviously low methanol permeability, which is attributed to the formed interrupted methanol transport channels arising from the combined properties of the hydrophobic BPPO polymeric backbone, the formed spherical BPPO obstacles and the cross-linking networks derived from the Friedel-Craft reaction between bromobenzyl groups and nucleophilic phenyl rings. Therefore, the SPEEK/BPPO membrane DMFC demonstrates a much higher cell performance both at low methanol concentration and high methanol concentration than the Nafion 117 DMFC. In particular, the actual value of the maximum power density at high methanol concentration of 20M suggests that the SPEEK/BPPO membranes can be considered as a desirable candidate for potential application in high methanol concentration DMFCs.

Minimizing methanol content in experimental charentais alembic distillations

This study focuses on using modern engineering tools to consistently produce spirits with low methanol content in Charentais alembics. The method involves developing a dynamic model, formulating a multi-objective dynamic optimization problem, and implementing an automatic process control system. Optimization yielded a variable temperature in the partial condenser, which was tracked by an automatic control system that manipulated the heat addition in the boiler. The procedure was experimentally validated in triplicate using a ternary mixture. With the optimal operation, distillates with 12% less methanol than standard distillates were reproducibly obtained, with a moderate reduction (2.4%) in the ethanol recovery.

FUSARIUM WILT DISEASE OF TOMATO: SCREENING FOR RESISTANCE AND IN-VITRO EVALUATION OF BOTANICALS FOR CONTROL; THE NIGERIA CASE

Fusarium wilt disease of tomato is caused by Fusarium oxysporum f. sp. lycopersici and is a limiting factor to tomato production in Nigeria. The objectives of this study were to screen tomato varieties commonly cultivated in Nigeria to determine their host resistance status to F. oxysporum, identify fungi species associated with tomato plants showing Fusarium wilt symptoms and the in-vitro evaluation of aqueous and methanol extracts of four botanicals for bioactivity. Symptomatic sample plants were collected from three farms in tomato producing communities of Nigeria. Isolation was done by direct plating method on acidified Potato Dextrose Agar (PDA). Fungi isolates were identified by cultural and microscopic characteristics. Extracts were prepared and evaluated for bioactivity by agar dilution method. The experiment was laid in a Completely Randomized Design replicated three times. Data were analyzed by descriptive and statistical analysis. Significantly different means were separated using Least Significant Difference at 5% level of significance. Of the nine varieties evaluated, only Tomato Shanty+N showed moderate resistance to F. oxysporum, while others were susceptible. Fungi isolated from symptomatic plants were Colletotrichum spp, Curvularia lunata, Sclerotia rolfsii, Rhizopus spp, Pestalocia macrotrica, Aspergillus spp, and Fusarium oxysporum. Extracts showed bioactivity against F. oxysporum at different concentrations. Methanol as solvent in preparing of Azadirachta indica leaf extract showed the highest inhibitory properties against F. oxysporum at low concentration. This was followed by Morinda lucida and Tagetes erecta at 37.5% and 25% concentration respectively. Tomato shanty+N and low concentration methanol extracts of Azadirachta indica leaf (12.5%) are therefore recommended.

Physicochemical and Sensorial Characterization of Honey Spirits.

Distilled spirits are usually made from fermented sugar-based materials, such as wines or fermented fruits, but other products can be used, namely berries or honey. In this work, an evaluation of honey spirits is done based on its physicochemical and sensory characteristics. Fourteen honey spirit samples of different brands of honey spirit were purchased at the market and from artisan Portuguese producers. Several analytical determinations, namely alcoholic strength, dry matter, density, total acidity, chromatic characteristics, methanol, acetaldehyde, ethyl acetate and higher alcohols were done to characterize all samples. The results pointed out several differences in physicochemical composition of samples. In general, these drinks are characterized by an alcohol strength between 37.4% and 53.0% and a low methanol content, quite null for most samples. Samples with higher ethanol content corresponded to the artisanal samples. Significant differences (p < 0.05) were also observed in the volatile composition and chromatic characteristics suggesting different production technologies. A first list of sensory attributes was obtained for this beverage. Therefore, further research must be done in order to characterize this spirit drink, which has gained market value.

Evidence of anomalous behavior of intermolecular interactions at low concentration of methanol in ethanol-methanol binary system

At low concentrations of methanol in a binary system of ethanol and methanol, uniquely complex molecular interactions are reported here. Previous studies indicate that ethanol molecules form aggregates held together by hydrogen bonding (O–H–O) and also dispersive forces. Addition of small amount of methanol tends to break the hydrogen bond network of ethanol due to the larger polarity of methanol. This leads to the ethanol molecules becoming somewhat isolated from each other within a scaffolding network of methanol molecules, as seen from the present molecular dynamics simulations. This is an indication of a repulsive force that dominates among the two different alcohols. At higher molar concentration of methanol (Xm > 0.3817), the strength and extent (number) of formation of hydrogen bonds between ethanol and methanol increase. The geometry of molecular structure at high concentration favors the fitting of component molecules with each other. Intermolecular interactions in the ethanol-methanol binary system over the entire concentration range were investigated in detail using broadband dielectric spectroscopy, FTIR, surface tension and refractive index studies. Molecular dynamics simulations show that the hydrogen bond density is a direct function of the number of methanol molecules present, as the ethanol aggregates are not strictly hydrogen-bond constructed which is in agreement with the experimental results.

Effect of polymer sulfonation on the proton conductivity and fuel cell performance of polyvinylalcohol‐mordenite direct methanol fuel cell membranes

AbstractSulfonated polyvinylalcohol‐mordenite (SPVA‐MOR) membranes for direct methanol fuel cell use were synthesized and characterized. It had earlier been found out that polyvinylalcohol‐mordenite (PVA‐MOR) membranes, while having excellent methanol permeability and modest proton conductivity values, had inferior direct methanol fuel cell performances than Nafion™. Sulfonating the polyvinylalcohol matrix had been suggested to improve the proton conductivity. In this work, polyvinylalcohol powder was sulfonated by using propane sultone as the sulfonating agent prior to the membrane synthesis. Morphological analyses revealed that the zeolite particles mixed homogeneously within the polymer matrix. Sulfonating the polymer slightly decreased both water and methanol uptakes. Both in PVA‐MOR and SPVA‐MOR membranes, water uptake turned out to be higher than the methanol uptake. SPVA‐MOR membranes were found to have an average proton conductivity of 0.052 S·cm−1 when compared with the 0.036 S·cm−1 of PVA‐MOR membranes, while Nafion™ has a proton conductivity of approximately 0.1 S·cm−1. The increase in the proton conductivity upon sulfonation despite the decrease in water uptake was explained by the dominance of the Grotthuss mechanism over the vehicular mechanism for proton conductivity. Fuel cell test results showed that while SPVA‐MOR membranes cannot outperform Nafion™, they give higher power output than PVA‐MOR membranes, especially at low temperatures and high methanol concentrations. © 2017 Curtin University of Technology and John Wiley &amp; Sons, Ltd.

Biodegradation of Phthalate Esters by a Newly Isolated Acinetobacter sp. Strain LMB-5 and Characteristics of Its Esterase

Phthalate esters (PAEs) are extensively applied in industry, and they migrate to environment during the process of production, employ, and treatment and are difficult to be degraded in nature. However, some microorganisms could use them as the carbon source to growth. In this study, an Acinetobacter sp. strain LMB-5, capable of utilizing PAEs, was isolated from a vegetable greenhouse soil. The degradation capability of strain LMB-5 was also investigated by incubation in mineral salt medium containing different PAEs, dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), and di-(2-ethylhexyl) phthalate (DEHP). The strain could grow well with DMP, DEP, DBP, and DEHP. When the concentration of DBP increased from 100 to 400 mg L−1, the half-life extended from 9.5 to 15.5 h. In the concentration range of DBP, the degradation ability of strain LMB-5 could be described by first-order kinetics. During the biodegradation of DBP, three intermediates, 1,2-benzenedicarboxylic acid, butyl methyl ester, DMP, and phthalic acid (PA) were detected, and the proposed pathway of DBP was identified. By analysis of bioinformatics, one esterase was cloned from the genome of LMB-5 and expressed in Escherichia coli. It displayed an ability to break the ester bonds of DBP. The enzyme exhibited maximal activity at pH 7.0 and 40 °C with DBP as the substrate. It was activated by Cu2+ and Fe3+ and had a high activity in the presence of low concentrations of methanol or dimethylsulfoxide (each 10%, volume:volume). The Acinetobacter sp. strain LMB-5 may make a contribution to the remediation of soils polluted by PAEs in the future.

Utilization and positive effects of produced CO2 on the performance of a passive direct methanol fuel cell with a composite anode structure

This study investigates the CO2 behavior and its effect on the performance of a passive direct methanol fuel cell (DMFC) by use of visualization method. Different flow field designs are introduced to the anode of the DMFC. The parallel-fence structure and the new composite structure with a sintered porous metal fiber felt (SPMFF) are experimentally compared in terms of the cell performance and mechanisms of reactant and product managements. Results show that the cell based on the composite structure yields the best performance during high-concentration operation. The vertical parallel-fence structure is more suitable at a lower methanol concentration. The visualization tests indicate that the use of a composite structure can help enhance convection due to CO2 self-promoting behavior and also enhance gas storage in the channel to control the methanol concentration. The presence of CO2 helps to restrain methanol crossover, which should be actively controlled to enhance internal convection and thereby improve the cell performance. The use of a composite structure enables the cell to perform stably for continuous operation at a higher methanol concentration. The open-circuit and dynamic characteristics of this composite-structure-based DMFC are also evaluated in this study.

An underrated variable essential for tailoring the structure of xerogel: the methanol content of commercial formaldehyde solutions

Resorcinol-formaldehyde xerogels are polymers whose porosity can be designed for a specific application by the selection of appropriate physical and chemical synthesis variables. Until recently, the methanol content of commercial formaldehyde solutions has never been considered as a chemical variable that must also be taken into account. However, it has been demonstrated that the proportion of methanol might be even more important than other variables for tailoring the porosity of xerogels. Different reaction mechanisms are proposed to explain this heavy dependence of the final structure of RF xerogels. Organic and carbon xerogels synthesized with low concentrations of methanol showed a higher porosity with much larger pore sizes (up to two orders of magnitude) than when using formaldehyde with high concentrations of methanol. This means that extra caution needs to be shown in choosing these commercial products since formaldehyde solutions differ greatly in methanol content from one supplier to another.

Molecular Dynamics Simulation and Experimental Study on the Growth of Methane Hydrate in Presence of Methanol and Sodium Chloride

The plugging of processing and transportation lines by gas hydrate formation is a challenging problem for safe exploitation of oil and gas. The existence of water soluble third component (like methanol and sodium chloride) in the aqueous phase influence the gas hydrate formation thermodynamically also possibly affects the kinetics of hydrate growth. Inorganic salt and organic molecule (alcohols) at high concentration in the aqueous phase have been used as thermodynamic inhibitors to effectively prevent the hydrate formation. This study utilizes molecular dynamics as well as an experimental method to investigate the mechanism of the hydrate formation and the effect of additives. The MD simulation showed that at moderate temperature and pressure, a low concentration (1wt %) of methanol and NaCl enhances methane hydrate growth kinetics. Significant numbers of methanol molecules were observed inside the gas hydrate cages whereas Na+/Cl− ions leach out during hydrate formation.

Efficient fuel utilization by enhancing the under-rib mass transport using new serpentine flow field designs of direct methanol fuel cells

New serpentine flow field designs of direct methanol fuel cells have been developed to enhance the under rib reactant mass transport without affecting the electronic conductivity to boost up the fuel utilization and fuel cell efficiency. The flow field design is based on three main criteria including the number of paths, the rib lengths, and the flow-path patterning in channels. Therefore, six different flow field designs are developed, including one design with two paths, two designs with three paths and different patterning and rib lengths, and three designs with four paths, different patterning and rib lengths. A three-dimensional single phase model for the direct methanol fuel cell is developed, simulated numerically and validated using the available experimental data. Results revealed that a significant enhancement of fuel cell performance is attained using the new designs. The design with the longest ribs and four paths attains the highest under-rib flows, and the lowest pressure drop between inlet and outlet. Furthermore, the power density has shown a 52.9% and 35.8% increase using an enhanced serpentine flow field with four paths compared to the conventional serpentine flow field design, at 0.5M and 0.25M inlet methanol concentrations. Using the new designs allows for the operating of the direct methanol fuel cell at a lower methanol concentration without a significant reduction of the output power.

Fast synthesis of ZSM-22 zeolite by the seed-assisted method of crystallization with methanol

This is a study of the fast synthesis of ZSM-22 zeolite using crystallization seeds and a cheap source of silica. The effect of crystallization time, addition of methanol as organic solvent, SiO2/Al2O3 ratio (SAR), alkalinity (OH−/SiO2 ratio), addition of potassium cation, and agitation were studied on the properties of the produced zeolite. Syntheses were performed at 170 °C with a fixed seed:SiO2 mass ratio of 10%. The seeds were synthesized by the hydrothermal method at 160 °C in the presence of 1,6-diaminohexane organic template. Products were characterized using X-ray diffraction, thermal analysis, nitrogen adsorption at −196 °C, and scanning electron microscopy. Under static conditions the best result was reached after 6 h of crystallization, obtaining a ZSM-22 with 80% crystallinity, in the presence of methanol, low alkalinity, without addition of K+ and SAR 100. The synthesis of ZSM-22 with SAR 50 using the same method resulted in a slightly lower crystallinity than with SAR 100. The increase in alkalinity or potassium concentration in the synthesis reaction medium decreased the crystallinity of the zeolite. Synthesis with the same composition under agitated condition increased the crystallinity and specific surface area of the zeolite and decreased reaction time from 6 to 4 h. The fastest synthesis was obtained under agitation with low methanol content in the reaction medium, obtaining the ZSM-22 structure after 3 h of reaction with higher crystallinity and surface area. The importance of fast synthesis is to reduce the cost of the zeolite production.

Modelling and simulation of passive feed direct methanol fuel cell

In this study, a mathematical model of the passive direct methanol fuel cell (DMFC) has been developed. This model considers the methanol and oxygen mass transport phenomena along with the electrochemical reactions. The model is validated with the experimental data. The model is used to predict the effect of methanol concentration on cell performance, variation of methanol crossover (MCO) with current density and methanol feed concentration, methanol and oxygen concentration profiles across the cell and the overpotentials. It was found that the MCO can be reduced by running the cell with low methanol concentration and at high current densities. Anode overpotential, compared to cathode overpotential, is found to be more responsible for the limiting current density. The outcome of the research will be useful for improving understanding of the transport phenomena in the passive DMFC and to optimise the cell design.

Early multidomain intervention to stave off Alzheimer&rsquo;s disease

Alzheimer’s disease is an irreversible, progressive brain disorder that slowly destroys memory and thinking skills, and eventually the ability to carry out the simplest tasks. In most people with Alzheimer’s symptoms first appear in their mid-60s. The typical lesions of Alzheimer’s disease (AD) feature in cognitive impairment, amyloid β (A β ) deposits (senile plaque), hyperphosphorylation of Tau in neurofibrillary tangles (NTFs), glial cells activation and cerebral atrophy. The plaques and tangles in the brain are considered to be the main features of Alzheimer’s disease. Loss of connections between neurons in the brain deteriorates neuronal message transmission between different parts of the brain, and from the brain to muscles and organs in the body. Over one hundred years, a great deal of research has been focused on the dementia of clinical phase, and on single-target drugs to intervene the progression of AD. However, a real breakthrough in the treatment still needs to be made to stave off AD. Currently, to clarify early pathological changes of pre-clinical stage is imperative to understand AD. Although aging, family history and susceptibility genes have been considered to be the most important factors, the rapid increase of AD patients does not conform to Hardy-Weinberg equilibrium. Therefore, environmental factors are more important than genetic factors in AD. The onset of human metabolic disorders becomes more related and vulnerable to endogenous and exogenous environmental pathogenic factors than genetics. Different environmental factors had been found to disrupt the binding affinity of Tau to microtubules or DNA, and to diminish the stability of its cellular skeleton by inducing Tau phosphorylation and amyloid β deposition. For example, five year-old monkeys (Macaca mulatta) which were administrated with low concentrations of methanol for 2 years and suffered from senile plaque, A β deposits, neurofibrillary like-tangles in parietal lobe and hippocampus. However, the direct relation between these environmental factors and neurodegenerative diseases is still waiting to be clarified. In order to stave off the onset and progression of AD, different interventions are emphasized and applied in AD treatments, such as developing multiple targeting drugs, ameliorating lifestyle, regulating diet, providing music care, attending physical exercises, and participating in social activities. Chronic dehydration is regarded as a common symptom of patients with age-related cognitive impairment, particularly those with Alzheimer disease. Chronic dehydration in mice results in dysregulation of brain formaldehyde, which decreases the level of 5-HT and slows learning in shuttle box. Establishing good water intake habits not only effectively eliminates excess formaldehyde and other metabolic products but also yields valuable approaches to reducing the risk of AD prior to the onset of the disease. The multidomain intervention will be one of comprehensive therapies for AD patients, especially for those in preclinical phase.

Prevalence of anxiety and patient relationship to the examination in the emergency department

The synthesis of anisole by vapor phase methylation of phenol with methanol over activated alumina (AA) supported catalysts was investigated in a fixed bed reactor. KH2PO4/AA gave the best performance among the eight tested catalysts. The catalyst was prepared by loading KH2PO4 on AA and then calcining at the optimized temperature of 700 °C for 8 h. In the vapor phase reaction, the level of anisole yield (LAY) has a maximum at 400–450 °C when the temperature varied from 300 to 500 °C, which decreased slightly with increasing WHSV and increased distinctly with increasing mole fraction of methanol. On comparing O-methylation and C-methylation of phenol, a low temperature, high WHSV (short residence time), and a low methanol concentration over the KH2PO4/AA catalyst with higher K contents were found to increase anisole selectivity by O-methylation of phenol. The reaction routes to the major products and the catalytic mechanism were suggested, and a ‘K-acid’ bifunctional process may be a critical factor to the formation of anisole.

Potentiating effects of thallium in sulfur mustard poisoning

The synthesis of anisole by vapor phase methylation of phenol with methanol over activated alumina (AA) supported catalysts was investigated in a fixed bed reactor. KH2PO4/AA gave the best performance among the eight tested catalysts. The catalyst was prepared by loading KH2PO4 on AA and then calcining at the optimized temperature of 700 °C for 8 h. In the vapor phase reaction, the level of anisole yield (LAY) has a maximum at 400–450 °C when the temperature varied from 300 to 500 °C, which decreased slightly with increasing WHSV and increased distinctly with increasing mole fraction of methanol. On comparing O-methylation and C-methylation of phenol, a low temperature, high WHSV (short residence time), and a low methanol concentration over the KH2PO4/AA catalyst with higher K contents were found to increase anisole selectivity by O-methylation of phenol. The reaction routes to the major products and the catalytic mechanism were suggested, and a ‘K-acid’ bifunctional process may be a critical factor to the formation of anisole.

Introduction to the microbiome

The synthesis of anisole by vapor phase methylation of phenol with methanol over activated alumina (AA) supported catalysts was investigated in a fixed bed reactor. KH2PO4/AA gave the best performance among the eight tested catalysts. The catalyst was prepared by loading KH2PO4 on AA and then calcining at the optimized temperature of 700 °C for 8 h. In the vapor phase reaction, the level of anisole yield (LAY) has a maximum at 400–450 °C when the temperature varied from 300 to 500 °C, which decreased slightly with increasing WHSV and increased distinctly with increasing mole fraction of methanol. On comparing O-methylation and C-methylation of phenol, a low temperature, high WHSV (short residence time), and a low methanol concentration over the KH2PO4/AA catalyst with higher K contents were found to increase anisole selectivity by O-methylation of phenol. The reaction routes to the major products and the catalytic mechanism were suggested, and a ‘K-acid’ bifunctional process may be a critical factor to the formation of anisole.

Viable Glycerol Carbonate Synthesis Through Direct Crude Glycerol Utilization from Biodiesel Industry

Synthesis of organic carbonates specifically glycerol carbonate has become a major concern among researchers due to its interesting chemical properties. In this study, we report the direct utilization of two different sources of crude glycerol in glycerolysis reaction with urea for the synthesis of glycerol carbonate using potassium silicate containing boiler ash as a catalyst. The level of interference of moisture and methanol content in crude glycerol was studied by mimicking conditions in pure glycerol and it was found that moisture at 10 wt% significantly effects the conversion of glycerol while methanol at 5 wt% affects the selectivity towards glycerol carbonate. However, due to the low moisture and methanol content in crude glycerol, comparable yield % of glycerol carbonate with commercial pure glycerol as starting feedstock was noted. Besides, the study also found that the potassium methylate and sodium methylate used as catalysts for the commercial production of biodiesel can be also used as an effective catalyst for the synthesis of glycerol carbonate. The current approach is a near approach for a greener environment which proposes use of both catalyst and glycerol derived from waste sources.

3D hepatic spheroid models for the detection and study of compounds with cholestatic liability

The synthesis of anisole by vapor phase methylation of phenol with methanol over activated alumina (AA) supported catalysts was investigated in a fixed bed reactor. KH2PO4/AA gave the best performance among the eight tested catalysts. The catalyst was prepared by loading KH2PO4 on AA and then calcining at the optimized temperature of 700 °C for 8 h. In the vapor phase reaction, the level of anisole yield (LAY) has a maximum at 400–450 °C when the temperature varied from 300 to 500 °C, which decreased slightly with increasing WHSV and increased distinctly with increasing mole fraction of methanol. On comparing O-methylation and C-methylation of phenol, a low temperature, high WHSV (short residence time), and a low methanol concentration over the KH2PO4/AA catalyst with higher K contents were found to increase anisole selectivity by O-methylation of phenol. The reaction routes to the major products and the catalytic mechanism were suggested, and a ‘K-acid’ bifunctional process may be a critical factor to the formation of anisole.

Effect of anode diffusion layer (GDL) on the performance of a passive direct methanol fuel cell (DMFC)

One of the most significant obstacles for passive direct methanol fuel cells is the methanol crossover, since methanol diffuses through the membrane generating heat but no power. This can be reduced if the cell operates with low methanol concentrations. However, this significantly reduces the energy density of the system since a large amount of water is presented on the anode side that will produce no power. Also, water crosses the membrane towards the cathode flooding it and reducing the cell performance. In the present work, different anode diffusion layers were tested in order to select optimal working conditions at high methanol concentrations. The results showed that the performance increased with an increase of carbon cloth thickness due mainly to a decrease of methanol crossover. Regarding the carbon paper, better performances were achieved for lower thicknesses and with a microporous layer (MPL) mainly due to a decrease of the anode overpotential achieved by a facilitated access of reactants. In this work, the best performance was achieved using carbon cloth for a methanol concentration of 3 M with a corresponding power density of 24.2 mW/cm2.