Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
150
result(s) for
"Gupta, Ram B"
Sort by:
Gasoline, diesel, and ethanol biofuels from grasses and plants
\"This book introduces readers to second-generation biofuels obtained from non-food biomass, such as forest residue, agricultural residue, switch grass, and corn stover\"--Provided by publisher.
Book
Utilization of MnFe2O4 Redox Ferrite for Solar Fuel Production via CO2 Splitting: A Thermodynamic Study
A thermodynamic efficiency analysis of MnFe2O4-based CO2 splitting (CDS) cycle is reported. HSC Chemistry software is used for performing the calculations allied with the model developed. By maintaining the reduction nonstoichiometry equal to 0.1, variations in the thermal energy required to drive the cycle and solar-to-fuel energy conversion efficiency as a function of the ratio of the molar flow rate of inert sweep gas to the molar flow rate of Mn-ferrite, reduction temperature, and gas-to-gas heat recovery effectiveness are studied. This study confirms that the thermal reduction temperature needed to achieve reduction nonstoichiometry equal to 0.1 is reduced when the inert gas flow rate is increased. Conversely, due to the requirement of the additional energy to heat the inert gas, the thermal energy required to drive the cycle is upsurged considerably. As the solar-to-fuel energy conversion efficiency depends significantly on the thermal energy required to drive the cycle, a reduction in it is recorded. As the ratio of the molar flow rate of inert sweep gas to the molar flow rate of Mn-ferrite is increased from 10 to 100, the solar-to-fuel energy conversion efficiency is decreased from 14.9% to 9.9%. By incorporating gas-to-gas heat recovery, a drastic drop in the thermal energy required to drive the cycle is attained which further resulted in a rise in the solar-to-fuel energy conversion efficiency. The maximum solar-to-fuel energy conversion efficiency (17.5%) is achieved at the ratio of the molar flow rate of inert sweep gas to the molar flow rate of Mn-ferrite equal to 10 as well as 20 when 90% of gas-to-gas heat recovery is applied.
Journal Article
Gasoline, Diesel and Ethanol Biofuels from Grasses and Plants
The world is currently faced with two significant problems: fossil fuel depletion and environmental degradation, which are continuously being exacerbated due to increasing global energy consumption. As a substitute for petroleum, renewable fuels have been receiving increasing attention due a variety of environmental, economic, and societal benefits. The first-generation biofuels - ethanol from sugar or corn and biodiesel from vegetable oils - are already on the market. The goal of thisbook is to introduce readers to second-generation biofuels obtained from non-food biomass, such as forest residue, agricultural residue, switch grass, corn stover, waste wood, municipal solid wastes, and so on. Various technologies are discussed, including cellulosic ethanol, biomass gasification, synthesis of diesel and gasoline, bio-crude by hydrothermal liquefaction, bio-oil by fast pyrolysis, and the upgradation of biofuel. This book strives to serve as a comprehensive document presenting various technological pathways and environmental and economic issues related to biofuels.
eBook
Advancements in Crude Oil Spill Remediation Research After the Deepwater Horizon Oil Spill
An estimated 4.9 million barrels of crude oil and natural gases was released into the Gulf of Mexico during the Deepwater Horizon oil spill of 2010. The Deepwater Horizon oil spill affected the aquatic species in the Gulf of Mexico, vegetation, and the human population along the coast. To reduce the effect of the spilled oil on the environment, different remediation strategies such as chemical dispersant, and mechanical booms and skimmers were utilized. Over 2.1 million gallons of dispersants was applied to minimize the impact of the spilled oil. However, environmental and human toxicity issues arose due to the perceived toxicity of the dispersant formulations applied. After the Deepwater Horizon oil spill, various studies have been conducted to find alternative and environmentally benign oil spill response strategies. The focus of this manuscript is to demonstrate an objective and an overall picture of current research work on oil spill response methods with emphasis on dispersant and oil sorbent applications. Current trends in oil spill sorbent and dispersant formulation research are presented. Furthermore, strategies to formulate environmentally benign dispersants, as well as the possible use of photoremediation, are highlighted.
Journal Article
Beneficiation of coal using supercritical water and carbon dioxide extraction: sulfur removal
This work explores the use of carbon dioxide, water, and their mixtures as solvent for the precombustion beneficiation of raw coal without using any toxic mineral acids in the temperature range of 200–400 °C. The fluid polarity, ionic constant, and supercritical point can be adjusted by H
2
O/CO
2
ratio and temperature. Adding carbon dioxide to hydrothermal fluid also increases the ionization by forming carbonic acid. Extractions with supercritical fluids have several benefits including enhanced mass transport, ease of separation and recycle, wide range of extractive capability and tunability, better inherent safety, and in the case of carbon dioxide and water–low cost. A semi-continuous extraction system was designed and built in which pressure, temperature and the relative flow rates of CO
2
and H
2
O can be controlled. Coal powder is kept in a packed bed and the extraction is carried out at 143 bar pressure. Using sulfur as a model heteroatom, extractive efficiency is examined as a function of the temperature, fluid composition, fluid flow, and extraction time. The results indicate that carbon dioxide, water, and supercritical water-carbon dioxide (ScWC) all can effectively extract about 50% of total sulfur from bituminous coal in 1 h. Extraction above 350 °C decreased effectiveness, and extraction above the supercritical point of pure water caused hydrothermal carbonization. ScWC extraction may provide necessary control to prevent organic dissolution while removing sulfur.
Journal Article
Environmentally benign nanomixing by sonication in high-pressure carbon dioxide
Due to the increased use of nanocomposites, mixing at nanoscale has become important. Current mixing techniques can be classified into: (a) dry mixing (mechanical mixing), (b) wet mixing, and (c) simultaneous production of mixed nanoparticles (when possible). Dry mixing is in general not effective in achieving desired mixing at nanoscale, whereas wet mixing suffers from different disadvantages like nanomaterial of interest should be insoluble, has to wet the liquid, and involves additional steps of filtration and drying. This paper examines the use of pressurized carbon dioxide having high density and low viscosity to replace the liquids (e.g.,
n
-hexane, toluene). Ultrasound is applied to the suspension of nanopowders in gaseous and supercritical carbon dioxide where high impact collisions during sonication help mixing and the final mixture is obtained by simple depressurization. The method is tested for binary mixture of alumina/silica, silica/titania, MWNT (multiwalled carbon nanotubes)/silica, and MWNT/titania. The effects of sonication intensity and pressure on the degree of mixing are studied. Comparative study is also done with liquid
n
-hexane as a mixing media. Quantitative characterization (e.g., mean composition standard deviation, intensity of segregation) of mixing of alumina/silica and silica/titania is done with energy-dispersive X-ray spectroscopy, and that of MWNT/silica and MWNT/titania is done using field-emission scanning electron microscopy and day-light illumination spectrophotometry. Results show that mixing in carbon dioxide at higher ultrasound amplitudes is as good as in liquid
n
-hexane, and the final mixed product does not contain any residual media as in the case of liquid
n
-hexane.
Journal Article
Correction to: Beneficiation of coal using supercritical water and carbon dioxide extraction: sulfur removal
In the original publication, there are few amendments to be made in Section 3.2 Extractive reactions involved.
Journal Article
Development and application of high-throughput screens for the discovery of compounds that disrupt ErbB4 signaling: Candidate cancer therapeutics
Whereas recent clinical studies report metastatic melanoma survival rates high as 30–50%, many tumors remain nonresponsive or become resistant to current therapeutic strategies. Analyses of The Cancer Genome Atlas (TCGA) skin cutaneous melanoma (SKCM) data set suggests that a significant fraction of melanomas potentially harbor gain-of-function mutations in the gene that encodes for the ErbB4 receptor tyrosine kinase. In this work, a drug discovery strategy was developed that is based on the observation that the Q43L mutant of the naturally occurring ErbB4 agonist Neuregulin-2beta (NRG2β) functions as a partial agonist at ErbB4. NRG2β/Q43L stimulates tyrosine phosphorylation, fails to stimulate ErbB4-dependent cell proliferation, and inhibits agonist-induced ErbB4-dependent cell proliferation. Compounds that exhibit these characteristics likely function as ErbB4 partial agonists, and as such hold promise as therapies for ErbB4-dependent melanomas. Consequently, three highly sensitive and reproducible (Z’ > 0.5) screening assays were developed and deployed for the identification of small-molecule ErbB4 partial agonists. Six compounds were identified that stimulate ErbB4 phosphorylation, fail to stimulate ErbB4-dependent cell proliferation, and appear to selectively inhibit ErbB4-dependent cell proliferation. Whereas further characterization is needed to evaluate the full therapeutic potential of these molecules, this drug discovery platform establishes reliable and scalable approaches for the discovery of ErbB4 inhibitors.
Journal Article
Hydrogen-bond cooperativity in 1-alkanol + n-alkane binary mixtures
Hydrogen‐bond cooperativity is an effect when hydrogen bonding is influenced by the previously formed hydrogen bond on the molecules. Using Fourier‐transform infrared spectroscopy, we have measured the extent of self hydrogen bonding in 1‐hexanol and 1‐pentanol dissolved in n‐hexane. Conventional theories without hydrogen‐bond cooperativity, such as the statistical‐association‐fluid theory, lattice‐fluid‐hydrogen‐bonding theory, and associated perturbed‐anisotropic‐chain theory, cannot represent the experimental data accurately. The extended lattice‐fluid‐hydrogen‐bonding theory that includes hydrogen‐bond cooperativity agrees well with the experimental data. Study suggests that the equilibrium constant for the second hydrogen bond on 1‐alkanol molecules is 10 times larger than that for the first hydrogen bond formation. Hence, strong hydrogen bond cooperativity exists in 1‐alkanol self association. Equations of state dealing with 1‐alkanol mixtures need to be modified to account for this strong hydrogen‐bond cooperativity.
Journal Article
Protein nanoparticles formation by supercritical antisolvent with enhanced mass transfer
In recent years, the supercritical antisolvent (SAS) precipitation technique has emerged as a promising method for the formation of fine particles. Despite its numerous advantages, this technique still cannot be used to produce particles in the sub‐micron range (<300 nm) for many “soft” materials. A significantly improved SAS process can produce particles of controllable size, up to an order of magnitude smaller than those of the conventional SAS process, with a narrower size distribution. Like the conventional SAS technique, this new supercritical antisolvent with enhanced mass transfer technique utilizes supercritical carbon dioxide as the antisolvent, but the solution jet is deflected by a surface vibrating at an ultrasonic frequency atomizing the jet into much smaller droplets. Furthermore, the ultrasound field generated by the vibrating surface enhances mass transfer and prevents agglomeration through increased mixing. The particle size is controlled by varying the vibration intensity of the deflecting surface, which then can be adjusted by changing the power supplied to the attached ultrasound transducer. It is demonstrated by the formation of lysozyme nanoparticles and microparticles. The biological activity of the protein is retained during the processing.
Journal Article