scholarly journals Restrictions on the Use of Specimens Based on Magnesium and Titanium Nanocrystalline Oxides in Incidents Involving Uncontrolled Release of Hazardous Substances

2019 ◽  
Vol 10 (1) ◽  
pp. 267
Author(s):  
Tomasz Węsierski ◽  
Małgorzata Majder-Łopatka ◽  
Agata Walczak
Keyword(s):  
Metal Oxides ◽  
Fire Hazard ◽  
High Surface ◽  
Hazardous Substances ◽  
Nanocrystalline Metal ◽  
Prompt Action ◽  
Nanocrystalline Oxides ◽  
Chemical Events ◽  
Very High

Undertaking effective and prompt action during chemical events is an important measure in preventing the spread of contamination. Studies have shown that despite very high surface activity of nanocrystalline metal oxides, their use does not reduce the fire hazard for hydrocarbon spills and alcohols more effectively than commonly used sorbents during fire rescue operations. Other limitations of specimens containing nanocrystalline oxides have also been proven, such as the maximum absorption similar to commonly used specimens, as well as high costs of conducting the acid neutralization process without increasing the level of safety of operations. Results obtained allowed the determination of proposed principles of effective and economically appropriate application of nanocrystalline metal oxides in rescue units.

Novel Preparation of Nano-Sized TiO2 and ZrO2 Particles by Nanocasting with Nanoporous SiO2 and Selective Dissolution

2007 ◽  
Vol 124-126 ◽  
pp. 643-646
Author(s):  
Jun Lee ◽  
Yoshihiro Sugi ◽  
Nam Jo Jeong ◽  
Gon Seo ◽  
Sung June Cho
Keyword(s):  
Metal Oxides ◽  
Surface Area ◽  
Pore Volume ◽  
High Surface ◽  
High Surface Area ◽  
Selective Dissolution ◽  
Metal Alkoxides ◽  
Nanocrystalline Metal

High surface area and uniform nano-sized TiO2 and ZrO2 were prepared readily by the infiltration of metal alkoxides into the nanoporous SiO2, SBA-15 and the following selective dissolution of SiO2. The obtained particles of TiO2 and ZrO2, 8.1 nm were nanocrystalline of which the structure were anatase and tetragonal, respectively. The surface area and pore volume of the nanocrystalline metal oxides can be increased to above 200 m2g-1 and 0.30 cm3g-1, respectively.

scholarly journals Two-step synthesis of Fe2O3and Co3O4nanoparticles: towards a general method for synthesizing nanocrystalline metal oxides with high surface area and thermal stability

RSC Advances ◽  
2012 ◽  
Vol 2 (1) ◽  
pp. 121-124 ◽  
Author(s):  
Junjiang Zhu ◽  
Xiaoying Ouyang ◽  
Ming-Yung Lee ◽  
Ryan C. Davis ◽  
Susannah L. Scott ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Metal Oxides ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Nanocrystalline Metal ◽  
General Method

Process Optimization with Acid Functionalised Activated Carbon derived from Corncob for Production of 4-Hydroxymethyl-2,2-Dimethyl-1,3-Dioxolane and5-Hydroxy-2,2-Dimethyl-1,3-Dioxane

2021 ◽  
Author(s):  
Jaspreet Kaur ◽  
Anil Sarma ◽  
Prof Mithilesh K Jha ◽  
Poonam Gera
Keyword(s):  
Active Sites ◽  
High Surface ◽  
High Surface Area ◽  
Reaction Parameters ◽  
Glycerol Conversion ◽  
Acidic Catalyst ◽  
The Face ◽  
Structural Deformity ◽  
Very High

Abstract This study focuses on the application of the corncob derived base (NaOH) activated and acid (H2SO4) functionalized carbons for the glycerol valorization to produce 2,2-Dimethyl-1,3-dioxolane-4-methanol (solketal), an oxygenated additive to fuel. The two derived catalysts viz., AAC-CC and AC-CC were subjected to various techniques for the determination of their structural properties and their comparison is made on the basis of characteristics and conversion into the final product. The conjugated boat structure of AAC-CC resulted very high surface area (779.8 m2/g) and higher pore volume (0.428cc/g) of AAC-CC that unveil its suitability as better among the two catalytic pathways during the solketal production. The acidic catalyst shows the highest catalytic activity as compared to basic due to the availability of the more active sites to the catalyst that will help in the reaction for higher conversion. The face cantered composite design (FCCD) of RSM was applied for the optimization of the reaction parameters for the ketalisation reaction. From the optimized results, the acidic catalyst AAC-CC gives higher glycerol conversion, i.e. 80.3% than the basic catalyst AC-CC i.e. 72.12% under the actual laboratory experiment. Moreover, the catalyst could be reused for three consecutive batch reactions without (< 5%) much reduction of activity and no distinctive structural deformity.

scholarly journals Torrential Flood Water Management: Rainwater Harvesting through Relation Based Dam Suitability Analysis and Quantification of Erosion Potential

2021 ◽  
Vol 10 (1) ◽  
pp. 27
Author(s):  
Bilal Ahmad Munir ◽  
Sajid Rashid Ahmad ◽  
Raja Rehan
Keyword(s):  
Sediment Yield ◽  
Soil Loss ◽  
Rainwater Harvesting ◽  
Suitability Analysis ◽  
Valley Bottom ◽  
The North ◽  
Roughness Index ◽  
Dam Site ◽  
Very High

In this study, a relation-based dam suitability analysis (RDSA) technique is developed to identify the most suitable sites for dams. The methodology focused on a group of the most important parameters/indicators (stream order, terrain roughness index, slope, multiresolution valley bottom flatness index, closed depression, valley depth, and downslope gradient difference) and their relation to the dam wall and reservoir suitability. Quantitative assessment results in an elevation-area-capacity (EAC) curve substantiating the capacity determination of selected sites. The methodology also incorporates the estimation of soil erosion (SE) using the Revised Universal Soil Loss Equation (RUSLE) model and sediment yield at the selected dam sites. The RDSA technique identifies two suitable dam sites (A and B) with a maximum collective capacity of approximately 1202 million m3. The RDSA technique was validated with the existing dam, Gomal-Zam, in the north of Sanghar catchment, where RDSA classified the Gomal-Zam Dam in a very high suitability class. The SE estimates show an average of 75 t-ha−1y−1 of soil loss occurs in the study area. The result shows approximately 298,073 and 318,000 tons of annual average sediment yield (SY) will feed the dam A and B respectively. The SE-based sediment yield substantiates the approximate life of Dam-A and Dam-B to be 87 and 90 years, respectively. The approach is dynamic and can be applied for any other location globally for dam site selection and SE estimation.

scholarly journals The Application of Electromagnetic Sensors for Determination of Cherenkov Cone Inside and in the Vicinity of the Detector Volume in Any Environment Known

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 992
Author(s):  
Valeriu Savu ◽  
Mădălin Ion Rusu ◽  
Dan Savastru
Keyword(s):  
Energy Levels ◽  
Cherenkov Detector ◽  
Electromagnetic Sensors ◽  
The Cost ◽  
Information Errors ◽  
The Universe ◽  
Large Frequency ◽  
Very High ◽  
Detector Volume

The neutrinos of cosmic radiation, due to interaction with any known medium in which the Cherenkov detector is used, produce energy radiation phenomena in the form of a Cherenkov cone, in very large frequency spectrum. These neutrinos carry with them the information about the phenomena that produced them and by detecting the electromagnetic energies generated by the Cherenkov cone, we can find information about the phenomena that formed in the universe, at a much greater distance, than possibility of actually detection with current technologies. At present, a very high number of sensors for detection electromagnetic energy is required. Thus, some sensors may detect very low energy levels, which can lead to the erroneous determination of the Cherenkov cone, thus leading to information errors. As a novelty, we propose, to use these sensors for determination of the dielectrically permittivity of any known medium in which the Cherenkov detector is used, by preliminary measurements, the subsequent simulation of the data and the reconstruction of the Cherenkov cone, leading to a significant reduction of problems and minimizing the number of sensors, implicitly the cost reductions. At the same time, we offer the possibility of reconstructing the Cherenkov cone outside the detector volume.

scholarly journals Single and Dual Metal Oxides as Promising Supports for Carbon Monoxide Removal from an Actual Syngas: The Crucial Role of Support on the Selectivity of the Au–Cu System

Catalysts ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 852 ◽  
Author(s):  
Bernay Cifuentes ◽  
Felipe Bustamante ◽  
Martha Cobo
Keyword(s):  
Metal Oxides ◽  
High Surface ◽  
High Surface Area ◽  
Carbon Deposits ◽  
Promising Strategy ◽  
Cu Catalysts ◽  
Dual Metal ◽  
Effect Of The Support ◽  
Lower Capacity

A catalytic screening was performed to determine the effect of the support on the performance of an Au–Cu based system for the removal of CO from an actual syngas. First, a syngas was obtained from reforming of ethanol. Then, the reformer outlet was connected to a second reactor, where Au–Cu catalysts supported on several single and dual metal oxides (i.e., CeO2, SiO2, ZrO2, Al2O3, La2O3, Fe2O3, CeO2-SiO2, CeO2-ZrO2, and CeO2-Al2O3) were evaluated. AuCu/CeO2 was the most active catalyst due to an elevated oxygen mobility over the surface, promoting CO2 formation from adsorption of C–O* and OH− intermediates on Au0 and CuO species. However, its lower capacity to release the surface oxygen contributes to the generation of stable carbon deposits, which lead to its rapid deactivation. On the other hand, AuCu/CeO2-SiO2 was more stable due to its high surface area and lower formation of formate and carbonate intermediates, mitigating carbon deposits. Therefore, use of dual supports could be a promising strategy to overcome the low stability of AuCu/CeO2. The results of this research are a contribution to integrated production and purification of H2 in a compact system.

scholarly journals Single–motor mechanics and models of the myosin motor

2000 ◽  
Vol 355 (1396) ◽  
pp. 441-447 ◽  
Author(s):  
T. Yanagida ◽  
S. Esaki ◽  
A. Hikikoshi Iwane ◽  
Y. Inoue ◽  
A. Ishijima ◽  
...  
Keyword(s):  
Single Molecule ◽  
Atp Hydrolysis ◽  
Accurate Determination ◽  
Step Size ◽  
Single Molecule Level ◽  
Detection Techniques ◽  
Myosin Motor ◽  
Mechanochemical Coupling ◽  
Chemical Events

Recent progress in single–molecule detection techniques is remarkable. These techniques have allowed the accurate determination of myosin–head–induced displacements and how mechanical cycles are coupled to ATP hydrolysis, by measuring individual mechanical events and chemical events of actomyosin directly at the single–molecule level. Here we review our recent work in which we have made detailed measurements of myosin step size and mechanochemical coupling, and propose a model of the myosin motor.

scholarly journals The determination of wormwheel toothing surface

2018 ◽  
Vol 157 ◽  
pp. 01013 ◽  
Author(s):  
Tadeusz Nieszporek ◽  
Rafał Gołębski ◽  
Piotr Boral
Keyword(s):  
Numerical Methods ◽  
Helical Surface ◽  
Heavy Industry ◽  
Manufacturing Costs ◽  
Rotary Tool ◽  
Large Size ◽  
Envelope Method ◽  
Worm Gears ◽  
Very High

In heavy industry (metallurgy, mining), large-size worm gears designed to carry large loads are often used. However, their technology is very difficult and their manufacturing costs are very high. In practice, cone-derivative worm gears are most often used, which are machined by the envelope method using a rotary tool. The literature has given much coverage to the determination of the worm helical surface. The surface of wormwheel teeth is much less commonly described. Therefore, this paper presents an analytical and a numerical methods for generating the wormwheel toothing by the tangential and radial methods with a special cutter and with a modular hob.

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