An Experimentally Verified Approach to Design Efficient Gasoline and Diesel Fuel Surrogates

Gasoline or diesel fuel sourced from crude oil source is a complex mixture of hundreds of hydrocarbons. It is extremely difficult to simulate for better understanding of the fuel flow and combustion behaviors which are essential to enhance fuel quality and to improve engine performance. To overcome this difficulty, a surrogate fuel, that has fewer compounds and that emulates certain important physical properties of a target fuel, can be utilized. The surrogate mixtures for both gasoline and diesel are designed through a computer aided model based technique by our collaborator at Technical University of Denmark (DTU), and their relevant target properties are predicted. Following the preparation of surrogate blends, target physical properties of both fuel surrogates are measured according to American Society of Testing and Materials (ASTM) methods using advanced analytical equipment in the Fuel Characterization Laboratory. For both gasoline and diesel surrogates, the model predictions are found to be in good agreement with the experimental results except for a few reported cases such as the Reid Vapor Pressure (RVP) of gasoline. For such cases, modifications are made to the model in order to improve the predicted results. Therefore, the experimental investigations are found to be extremely essential for improving the assumptions used to define interactions of the hydrocarbons in the mixtures, which in turn enables enhanced predictability of the model. The developed model, which leads to a property driven product, can be further investigated to prepare new fuel blends and identify suitable renewable additives in a known amount that can aid in designing of future generation of fuels obtained from either conventional crude oil sources or non-conventional sources. Even though this model provides an excellent, fast and reliable opportunity for screening large number of fuel surrogates and optimization of the same, it is extremely important to experimentally verify the final blends and fine-tune them if necessary before their utilization in engine. Also, the measured property values help to improve the accuracy of the property models as well as the assumptions used to develop them

Adsorbed Hydroxide Does Not Participate in the Volmer Step of Alkaline Hydrogen Electrocatalysis

The sluggish kinetics of the alkaline hydrogen electrode have been attributed to the need to adsorb both H and OH optimally. In this work, single-crystal voltammetry and microkinetic modeling show that an OH-mediated mechanism is not viable on Pt(110). Only a direct Volmer step can explain observed kinetic trends with OH adsorption strength in KOH and LiOH electrolytes. Instead, OH behaves as a rapidly equilibrated spectator species that decreases available surface sites and slows hydrogen kinetics. These results identify kinetic barriers from interfacial water structure, not adsorption energies, as key to explaining changes in hydrogen kinetics with pH

Caffeinated Interfaces Enhance Alkaline Hydrogen Electrocatalysis

The high Pt loading required for hydrogen oxidation (HOR) and evolution (HER) reactions in alkaline fuel cells and electrolyzers adversely impacts the system cost. Here, we demonstrate the use of caffeine as a ‘double-layer dopant’ to enhance both the HER and HOR of Pt electrodes in base. HER/HOR rates increase by fivefold on Pt(111) and are accelerated on Pt(110), Pt(pc), and Pt/C as well. FTIR spectroscopy confirms that caffeine is adsorbed at the Pt surface, forming a self-limiting film through electrochemical deposition. Caffeine films are stable up to 1.0 V vs. RHE and are readily regenerated through caffeine deposition during load/potential cycling. The findings presented here both identify a potential catalyst additive that can mitigate high Pt loadings in alkaline fuel cells and electrolyzers while opening the door to molecular engineering of solid/liquid interfaces for energy storage and conversion.</p

Draft genome sequence of Ochrobactrum intermedium strain SA148, a plant growth-promoting desert rhizobacterium

Ochrobactrum intermedium strain SA148 is a plant growth-promoting bacterium isolated from sandy soil in the Jizan area of Saudi Arabia. Here, we report the 4.9-Mb draft genome sequence of this strain, highlighting different pathways characteristic of plant growth promotion activity and environmental adaptation of SA148

Draft genome sequence of Enterobacter sp. Sa187, an endophytic bacterium isolated from the desert plant Indigofera argentea

Enterobacter sp. Sa187 is a plant endophytic bacterium, isolated from root nodules of the desert plant Indigofera argentea, collected from the Jizan region of Saudi Arabia. Here, we report the genome sequence of Sa187, highlighting several genes involved in plant growth-promoting activity and environmental adaption

Draft genome sequence of the plant growth-promoting rhizobacterium Acinetobacter radioresistens strain SA188 isolated from the desert plant Indigofera argentea

Acinetobacter radioresistens strain SA188 is a plant endophytic bacterium, isolated from root nodules of the desert plants Indigofera spp., collected in Jizan, Saudi Arabia. Here, we report the 3.2-Mb draft genome sequence of strain SA188, highlighting characteristic pathways for plant growth-promoting activity and environmental adaptation

Stoichiometry and surface structure dependence of hydrogen evolution reaction activity and stability of MoxC MXenes

The exploration of non-precious catalysts for the hydrogen evolution reaction (HER) remains critical in the commercialization of electrochemical energy storage and conversion technologies. Two-dimensional transitional metal carbides called MXenes have been found to have great potential as electrocatalysts for HER. In this work, we synthesize two molybdenum-based MXenes: Mo1.33CTz and Mo2CTz, and measure their HER activity and operational durability. The ordered divacancies on the basal planes of Mo1.33CTz cause a marked decrease in HER activity compared to Mo2CTz. The stoichiometry and atomic surface structure of MXenes is found to be critically important for catalytic activity while having less of an impact on operational durability. This work provides insight for the development of active 2D materials, in general and MXenes in particular for HER and other technologically relevant electrochemical reactions. (C) 2019 Elsevier Inc. All rights reserved.Funding Agencies|NSF CBET-Catalysis [1602886]; Swedish Research Council [642-2013-8020]; Knut and Alice Wallenberg (KAW) Foundation; Swedish Foundation for Strategic Research (SSF) [EM16-0004]</p

Genome insights of the plant-growth promoting bacterium Cronobacter muytjensii JZ38 with volatile-mediated antagonistic activity against Phytophthora infestans

Salinity stress is a major challenge to agricultural productivity and global food security in light of a dramatic increase of human population and climate change. Plant growth promoting bacteria can be used as an additional solution to traditional crop breeding and genetic engineering. In the present work, the induction of plant salt tolerance by the desert plant endophyte Cronobacter sp. JZ38 was examined on the model plant Arabidopsis thaliana using different inoculation methods. JZ38 promoted plant growth under salinity stress via contact and emission of volatile compounds. Based on the 16S rRNA and whole genome phylogenetic analysis, fatty acid analysis and phenotypic identification, JZ38 was identified as Cronobacter muytjensii and clearly separated and differentiated from the pathogenic C. sakazakii. Full genome sequencing showed that JZ38 is composed of one chromosome and two plasmids. Bioinformatic analysis and bioassays revealed that JZ38 can grow under a range of abiotic stresses. JZ38 interaction with plants is correlated with an extensive set of genes involved in chemotaxis and motility. The presence of genes for plant nutrient acquisition and phytohormone production could explain the ability of JZ38 to colonize plants and sustain plant growth under stress conditions. Gas chromatography–mass spectrometry analysis of volatiles produced by JZ38 revealed the emission of indole and different sulfur volatile compounds that may play a role in contactless plant growth promotion and antagonistic activity against pathogenic microbes. Indeed, JZ38 was able to inhibit the growth of two strains of the phytopathogenic oomycete Phytophthora infestans via volatile emission. Genetic, transcriptomic and metabolomics analyses, combined with more in vitro assays will provide a better understanding the highlighted genes’ involvement in JZ38’s functional potential and its interaction with plants. Nevertheless, these results provide insight into the bioactivity of C. muytjensii JZ38 as a multi-stress tolerance promoting bacterium with a potential use in agriculture

Complete Genome Sequence Analysis of Enterobacter sp. SA187, a Plant Multi-Stress Tolerance Promoting Endophytic Bacterium

Enterobacter sp. SA187 is an endophytic bacterium that has been isolated from root nodules of the indigenous desert plant Indigofera argentea. SA187 could survive in the rhizosphere as well as in association with different plant species, and was able to provide abiotic stress tolerance to Arabidopsis thaliana. The genome sequence of SA187 was obtained by using Pacific BioScience (PacBio) single-molecule sequencing technology, with average coverage of 275X. The genome of SA187 consists of one single 4,429,597 bp chromosome, with an average 56% GC content and 4,347 predicted protein coding DNA sequences (CDS), 153 ncRNA, 7 rRNA, and 84 tRNA. Functional analysis of the SA187 genome revealed a large number of genes involved in uptake and exchange of nutrients, chemotaxis, mobilization and plant colonization. A high number of genes were also found to be involved in survival, defense against oxidative stress and production of antimicrobial compounds and toxins. Moreover, different metabolic pathways were identified that potentially contribute to plant growth promotion. The information encoded in the genome of SA187 reveals the characteristics of a dualistic lifestyle of a bacterium that can adapt to different environments and promote the growth of plants. This information provides a better understanding of the mechanisms involved in plant-microbe interaction and could be further exploited to develop SA187 as a biological agent to improve agricultural practices in marginal and arid lands