RDX-Aluminum Interaction——A DFT Study

Within the constraints of density functional theory (UB3LYP/6‐311+ +G(d ,p)) ,RDX/Al and RDX/2Al composites are investigated ,considering various multiplicity states (singlet and triplet states) .Depending on the localization of Al atom(s) in space and multiplicity of the composite systems ,the structure of RDX undergoes various degrees of perturbations .It has been shown that the presence of Al atoms affects the bond lengths ,electron population as well as the HOMO and LUMO energies and the inter frontier molecular orbital energy gap of RDX .All these perturbations are thought to affect ballistic properties of the ex‐plosive molecule RDX .     

A Study on Self—flow Castable Refractory

It has been reported that the main factors which influence the properties of self-flow castable are:1) the particle size distribution and 2) the function of dispersant and surfactant ,In the present paper,the optimum range of particle size distribution and the best ispersant and surfactant as well as the function mechanisms are discussed,Also a method to eveluate self-flow castable are given.     

Quire Interaction of Certain Nitramine Type Explosives with Proton——A DFT Study

The composites of certain nitramine type explosives, TETRYL, RDX and EDNA, with proton in vacuum have been considered within the constraints of density functional theory at the level of B3LYP/6-31++G(d,p) (restricted and unrestricted).The results indicate that unexpectedly hydrogen molecule production occurs by the interaction of proton and a hydrogen of CH3 (TETRYL) and CH2 (RDX and EDNA) groups.As a result, a carbocation is generated on the explosive molecules.Thereafter, TETRYL which potentially has many protonation sites were investigated in more detail in vacuum and aqueous conditions.The data reveals that the composite system (TETRYL+proton) is less stable than TETRYL protonated on nitramine NH or oxygen of the nitro groups.     

Modular P?OP Ligands in Rhodium‐Mediated Asymmetric Hydrogenation: A Comparative Catalysis Study

Highly efficient and enantioselective hydrogenation reactions for α‐(acylamino)acrylates, itaconic acid derivatives and analogues, α‐substituted enol ester derivatives, and α‐arylenamides (25 substrates) catalyzed by chiral cationic rhodium complexes of a set of P OP ligands have been developed. The catalytic systems derived from these P OP ligands provided a straightforward access to enantiomerically enriched α‐amino acid, carboxylic acid, amine, and alcohol derivatives that are valuable chiral building blocks. Excellent efficiencies (full conversion in all cases) and extremely high enantiomeric excesses (94–99% ee) were achieved for a wide range of α‐substituted enol ester derivatives, regardless of the substitution pattern. The R‐oxy group of the ligand (methoxy or triphenylmethoxy) strongly influences the enantioselectivity and catalytic activity. Greater steric bulk around the metal centre correlated to greater (or similar) enantioselectivity, but also to slower hydrogenation. Furthermore, the hydrogenation rates observed with the four model substrates follow the same trend, independently of the R‐oxy group of the ligand: methyl 2‐acetamidoacrylate>dimethyl itaconate>1‐phenylvinyl acetate>N‐(1‐phenylvinyl)acetamide. A substrate‐to‐catalyst ratio (S/C) of up to 10,000:1 was sufficient for total hydrogenation of a model substrate of intermediate reactivity (dimethyl itaconate), and did not imply any loss in conversion or enantioselectivity.     

A Study on Electrically Conducting Magnesia—carbon Bricks for DC EAF

This paper gives a brief introduction to a kind of special refractories for DC EAF-electrically conducting magnesia-carbon bricks.The application of the conductive magnesia-carbon brick as a hearth electrode is a trend of development in DC arc furnace hearth bootom because of its features of anti corrosion and easy repatching,This is a proven process already available abroad.After a study of teh effect of different amount of graphite added and pretreating temperatures on the eletric-conductivity of magnesia-carbon bricks it has been found that for a balance between electric and thermal conductivities,the proper amount of graphite to be added should be 8%-14% and the pretreatment at temperature of 1300-1500℃ will result in the formation inside the magnesia-carbon bricks of a continuous three-dimensional network of graphite and semi-coke,thus making the brick conductive.     

Isomeric Structures of Furoxan-Fused [2,2]paracyclophane—A DFT Study

The present study theoretically deals with furoxan-fused [2,2]paracyclophane systems and some structures possibly involved in their isomerization processes. These intermediate structures are certain di- and tetra-nitroso derivatives and systems having dioxadiazatidine ring(s). Computationally, B3LYP/6–31G(d,p) level of density functional theory has been employed. Certain properties of the systems, such as geometries, energies, and aromaticity of the benzenoid rings, are harvested and discussed.     

Furoxan Derivatives of Pyrene – A DFT Study

Furoxan-fused pyrenes and their dinitroso derivatives (obtained by furoxan ring opening) are considered for density functional treatment at the level of B3LYP/6-31G(d,p). Embedded benzofuroxan moiety in the furoxan-fused pyrene system is thought to undergo ring opening and reclosure process analogously to benzofuroxan itself. The stabilities, structural features, NICS(0) values, IR, and UV-VIS spectral aspects, etc., are investigated comparatively for these isomeric furoxan-fused pyrenes and their isomeric dinitroso derivatives.     

α-Synuclein Oligomers: A Study in Diversity

A critical step in Parkinson's disease (PD) is the formation of toxic α-synuclein oligomers (αSOs). In vitro αSOs are formed by self-assembly of α-synuclein at high concentrations, or by the addition of, for example, dopamine, lipids, ethanol, or metal ions. These αSOs are structurally distinct from the unfolded monomer and aggregated β-sheet fibrils. Nevertheless, the literature reports a wide variety of αSO shapes, sizes, and proposed toxic mechanisms. This heterogeneous character makes it difficult to form a unifying picture. Here, we present an overview of the different αSO species made in vitro, providing a tool for better comparison of different protocols and the ensuing αSOs, and emphasizing the striking versatility in the appearance and properties of these critical species. We also summarize what is known of the biological activities of different αSOs. Despite a large and increasing level of insight into αSO effects in vitro, we still lack strong insight into the structures and sizes of αSO species formed in vivo. Once this is established, it may be possible to generate more uniform protocols that could stimulate further efforts to develop viable PD biomarker assays and therapies.     

SOME THEORETICAL PROBLEMS OF ANIONIC POLYMERIZATION OF BUTADIENE——A Study on the Association Degree of n-BuLi and Polybutadienyl-Li

This paper determined the association degree of n-BuLi and polybutadinyllithium(PBLi)by UV spec-trometry and viscometry.The experimental results of UV spectrometric analysis showed that the associationdegree of n-BuLi as well as PBLi is dependent mainly on their concentration in solutions;there may be specieswith three and two degrees of association in cyclohexane solvent respectively for n-BuLi and PBLi,i.e.the asso-ciation degree for the former is equal to 2,4 and 6;and for the latter it equals to 2 and 4.Similarly,the experi-mental results obtained by viscometric measurement showed that the average association degree N of PBLiin cyclohexane changed from 2 to 4 with increasing of its concentration in solution and decreased with addi-tion of a small amount of polar additive into the above mentioned system.Furthermore,in pure polar solvent,such as dimethoxyethane(DME),tetrahydrofuran(THF)or dioxane(DOX),PBLi is completely dissociatedinto monomeric species;however,in pure diethyl ether,due to its weak polarity a part of associated species stillcan be found.Generally speaking,all of the above results were consistent with the results of kinetic studies in-vestigated by us before.     

Effect of Surface Motion on Transport Processes Due to Circular Impinging Jets—A Numerical Study

This article presents a numerical study of transport phenomena under impinging circular jet banks over a moving surface by solving three-dimensional Navier-Stokes equation in both the laminar and the turbulent regime. A periodic element of the jet bank was used with jet pitch of 10d, span of target surface as 10d, and jet height of 2d, where d is the jet diameter. For the turbulent closure, a realizable k-ε model was used. The distributions of the Nusselt number and the skin friction coefficients were computed from the analyzed data. The surface velocity was found to influence strongly the flow structure over the impinging surface, leading to reduction in heat transfer.     

Techno-Economic Evaluation of Biodiesel Production from Waste Cooking Oil—A Case Study of Hong Kong

Fossil fuel shortage is a major challenge worldwide. Therefore, research is currently underway to investigate potential renewable energy sources. Biodiesel is one of the major renewable energy sources that can be obtained from oils and fats by transesterification. However, biodiesel obtained from vegetable oils as feedstock is expensive. Thus, an alternative and inexpensive feedstock such as waste cooking oil (WCO) can be used as feedstock for biodiesel production. In this project, techno-economic analyses were performed on the biodiesel production in Hong Kong using WCO as a feedstock. Three different catalysts such as acid, base, and lipase were evaluated for the biodiesel production from WCO. These economic analyses were then compared to determine the most cost-effective method for the biodiesel production. The internal rate of return (IRR) sensitivity analyses on the WCO price and biodiesel price variation are performed. Acid was found to be the most cost-effective catalyst for the biodiesel production; whereas, lipase was the most expensive catalyst for biodiesel production. In the IRR sensitivity analyses, the acid catalyst can also acquire acceptable IRR despite the variation of the WCO and biodiesel prices.     

Cannibalism Affects Core Metabolic Processes in Helicoverpa armigera Larvae—A 2D NMR Metabolomics Study

Cannibalism is known in many insect species, yet its impact on insect metabolism has not been investigated in detail. This study assessed the effects of cannibalism on the metabolism of fourth-instar larvae of the non-predatory insect Helicoverpa armigera (Lepidotera: Noctuidea). Two groups of larvae were analyzed: one group fed with fourth-instar larvae of H. armigera (cannibal), the other group fed with an artificial plant diet. Water-soluble small organic compounds present in the larvae were analyzed using two-dimensional nuclear magnetic resonance (NMR) and principal component analysis (PCA). Cannibalism negatively affected larval growth. PCA of NMR spectra showed that the metabolic profiles of cannibal and herbivore larvae were statistically different with monomeric sugars, fatty acid- and amino acid-related metabolites as the most variable compounds. Quantitation of ¹H-¹³C HSQC (Heteronuclear Single Quantum Coherence) signals revealed that the concentrations of glucose, glucono-1,5-lactone, glycerol phosphate, glutamine, glycine, leucine, isoleucine, lysine, ornithine, proline, threonine and valine were higher in the herbivore larvae.     

A Quantitative Multi-Criteria Solvent Selection Method for Extraction Processes: Case Study—Downstream Purification of Sucrose-Based Surfactants

This work developed a novel method for the identification and selection of green solvents for extraction processes. The methodology was experimentally validated in the downstream separation of sucrose-based surfactants obtained from a solvent-free transesterification of sucrose and methyl palmitate (MP). First, a preliminary solvent screening was carried out taking into account environmental consciousness, extraction effectiveness, and predicted operating costs, combining both theoretical and empirical inputs. Potential solvents were first selected from a green solvents list used at the pharmaceutical industry, and the affinity with reactants was assessed based on the Hansen solubility parameters. Solvent suitability was ranked according to a novel objective function that incorporated the heat of vaporization, normal boiling point, cost, and availability. In the case of study, ethyl acetate was identified as the most promising solvent for MP extraction. This and other solvents were experimentally evaluated to validate the selection method and to assess their extraction performance. According to different effectiveness criteria, ethyl acetate was confirmed as the preferable extraction solvent. Finally, MP extraction from reaction media was optimized, varying temperature, number of stages, and solvent loading. Purified sucrose esters were subjected to bleaching obtaining a product under market specifications.     

A Preliminary Study of the Plasma Pyrolysis of Waste Tyres

Thermal plasma pyrolysis of waste tyres for recovering energy was performed in a nitrogen plasma reactor. The main gaseous products were identified by chromatography as H2, CO, CH4, C2H2 and so on. From a series of experiments, the effects of the process parameters of thermal plasma pyrolysis were investigated. Under our experimental conditions with steam injection, the total contents of H2 and CO reached up to 38.3% in the gas product, C2H2 up to 4%, and the maximum calorific value of the pyrolysis gas was 8.96 MJ/m3. The results indicate that plasma-assisted thermal decomposition of waste tyre particles may be a useful way for recovering energy and useful chemicals.     

Coal Slag Attack—— A Review

Although slagging coal gasifiers have served the commercial systerrrs of electricity and chemical fertilizer productions for more than ten years, refractory service life still is a critical factor for gasifier availability. Some investigations were attracted, focusing on coal slag attack on high chromia refractories. A general introduction is made in order to have further uruterstandlng about slag corrosion in coal gasification environment. Microstructural deterioration and wear process of high chromia refractory in slagging gasifiers are discussed.     

Study of Sorption of Viscose—Polyamide and Viscose—Polyester Composite Fibres

The use of composite viscose—polyamide and viscose—polyester fibres significantly improves the comfort properties of fabrics and knits. The sorption power of the composite fibres is higher the higher the viscose component content is, since polyester and polyamide fibres are almost nonhygroscopic. Increasing the relative humidity from 66 to 98% increases the moisture content of these fibres by 2-3 times.     

Study on Slag Resistance of Self—flowing Type Alumina—Spinel Castable

Four kinds of slags with different compositions have been chosen for comparing the slag resistance of the castable by crucible slag test,It is found that CaO/SiO2 ration and rerrite content have certain influence on the slag resistance of the castable.     

Interaction of Cetrimide with Nonionic Surfactants—Triton X-100 and Brij-35: A Conductometric and Tensiometric Study

Conductometric and surface tension techniques were employed to study the different mole fractions of nonionic surfactants (TX-100 and Brij-35) with cetrimide. The standard Gibbs energies of micellization (\(\Delta G_{\text{m}}^{0}\)) and the Gibbs energies of transfer (\(\Delta G_{\text{trans}}^{0}\)) in the mixture of surfactants were also calculated; the micellization becomes more spontaneous on increasing the amount of nonionic surfactants in the mixture. It was observed that the values of excess surface concentration (Γ_max) in surfactant mixtures decrease in comparison to the pure surfactants but the values of minimum area per surfactant molecule (A _min) increase in surfactant mixtures than in the pure ones. It was also observed that the values of the interaction parameter (β) are negative at all mole fractions. A gradual decrease in β with temperature is observed indicating the synergism between the two components and is attributed to the decrease in the electrostatic repulsion between the charged heads of the cationic surfactant as the nonionic surfactant is being intercalated into the micelle. The activity coefficients were found out to be less than unity confirming nonideality of the system and the negative values of excess free energy of mixing confirm that the mixed micelles formed were stable.