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The nature of interaction between coal surface and collector molecule affects the yield of fine coal flotation. The interaction depends on coal surface characteristics and collector polarity as well as collector size. In this work, a detail understanding on the interaction nature of nonpolar such as dodecane (C1) and polar collectors such as tetrahydrofurfuryl oleate (C2) and 2-[2-[2-[2-[2-[2-(2-hydroxyethoxy)ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethyl(Z)-octadec-9-enoate (C3) with low-rank coal is presented using density functional theory calculations and finite temperature large scale ReaxFF molecular dynamics simulations. It has been shown that collector consisting of more electronegative elements (i.e. with larger polarity) show stronger interaction with low-rank coal. Moreover, larger aliphatic chain helps to interact via van der Walls interactions and polar functional groups through electrostatic interaction (hydrogen bond formation) due to flexibility in the collector backbone. Interestingly, the collectors did not show any spike like attachment to the low-rank coal surface, rather lies along the coal surface to maximize the possible interactions. This contrasts with commonly presented picture for collector-(low-rank) coal surface interaction. Optimal requirement of aliphatic chain length and polar functional groups was discussed by analyzing structure properties relationship. [ABSTRACT FROM AUTHOR]

This article proposes a novel drivetrain design of a solar-powered e-rickshaw with the controller. Hall-Effect position sensorless brushless dc (BLDC) motor drive often suffers from delayed commutation at high speed and even at low speed, conventional control does not work well due to low magnitude of back EMF. Here, the proposed sensorless control with commutation error compensation is implemented, which drives the motor over the entire range. A simple commutation error compensation algorithm is designed to detect the freewheeling pulses, reducing the control complexity for low-cost EV application and eliminating low pass filter requirement. Moreover, a zero-crossing detection (ZCD) algorithm is suggested, which inherently compensates the delay and removes the need of any additional phase compensator. A fixed delay digital filter is used to eliminate any unwanted spikes in ZCD circuit. For effective MPPT control, a modified Landsman converter is used, which provides ripple-free current at output and reduces the requirement of ripple filter at front end. The BLDC motor drive is capable of energy regeneration, which reduces the range anxiety for EV. The solar energy and the battery ensure that the vehicle never runs out of power irrespective of the climate conditions. The average distance covered by the vehicle on a single charge is improved. [ABSTRACT FROM AUTHOR]

The gallol group, which contains three adjacent hydroxyl groups on a benzene, is a new bioinspired functional group for adhesives applications. The chemical structure of the gallol group possesses one more hydroxyl group on a benzene than the well-studied mussel-inspired adhesive group, catechol. Despite the small difference in chemical structure, gallol containing adhesive polymers show 7 times higher wet adhesion properties than the catechol containing adhesives under the identical experimental conditions. On account of the large enhancement of adhesion properties, the gallol containing adhesive polymers are gaining significant interest, and the related polymer science fields are expected to grow quickly. This review summarizes synthesis methods and diverse applications of gallol containing adhesive polymers. The goal of this review is to provide reasonable pathways for selecting and designing gallol containing polymer structures to maximize the adhesion properties for functional applications. [ABSTRACT FROM AUTHOR]

Adsorption mechanism and inhibitive performances of alkaloids on mild steel are studied using density functional theory (DFT). Global reactivity parameters such as global hardness (ɳ), fraction of electron transfer from molecule to metal (∆N), and dipole moment (μ) are calculated to determine corrosion protection efficiency. Periodic DFT calculations show bonding interactions between heteroatoms of alkaloid and Fe atom of Fe(110) surface. Fe–-H non-classical bond formations are also observed. The order of adsorption energy (Eads) is quinine (86.6 kcal/mol) > cytisine (67.6 kcal/mol) ≈ mescaline > ephedrine > morphine ≈ atropine > nicotine > caffeine > tryptamine > codeine (50.2 kcal/mol). Highest Eads value of quinine is interpreted with its very favourable orbital energies that help to form chemical bonds via electron donation and back donation. These high Eads values confirmed chemisorption process and interpreted strong inhibition efficiencies of morphine and caffeine on mild steel as reported in experimental studies. [ABSTRACT FROM AUTHOR]

• This review covers the recent advances and challenges of polymer–graphene nanocomposites (PGNs) as materials for wearable strain sensors, to monitor various human motions and physiological signals. • The classification of PGNs based on the types of graphene and the strain sensing mechanisms, and discussions regarding the fabrication methods of PGN-based strain sensors have been introduced. • It showcases the functional PGN-based strain sensors using various polymers and their applications in different fields, and identifies the future directions of PGN-based wearable strain sensors for accurate and reliable physiological signal monitoring. Wearable strain sensors are emerging as promising devices for monitoring human motions and physiological signals in various fields, such as healthcare, robotics, and sports. Among various materials, polymer–graphene nanocomposites (PGNs) have attracted considerable attention due to their excellent mechanical, electrical, and thermal properties, as well as their facile fabrication methods. This review summarised the recent progress and challenges of PGN-based wearable strain sensors for physiological signal monitoring. First, the classification of PGNs based on the structural derivatives of graphene (such as graphene sheets, graphene oxide, reduced graphene oxide, and graphene quantum dots) and the strain sensing mechanisms (such as resistive and capacitive) were introduced. Then, we discussed the fabrication approaches of PGN-based strain sensors, including solution processing, melt blending, in-situ polymerization, spinning, printing, and coating. Afterward, this article highlighted the functional PGN-based strain sensors using various polymers and their applications in monitoring subtle and significant physiological signals. Finally, this work identified the underlying challenges and future perspectives of PGN-based wearable strain sensors for accurate and reliable physiological signal monitoring. This review provides a comprehensive overview of the current state-of-the-art of PGN-based wearable strain sensors and inspires further research in this field. [ABSTRACT FROM AUTHOR]

Inorganic binders like bentonite, used for pelletization of low-grade iron ore, generate iron ore slimes with comparatively high silica and alumina content necessitating extra steps for their removal during iron making process. This demands the usage of organic binders as full or partial replacement of bentonite for iron ore pelletization. In this work, adsorption of organic binders with saccharides skeleton and –H, –OH, –CH 2 OH and –CH 2 CH 2 OH as polar substituents, on goethite surface was studied using density functional theory, molecular dynamics and machine learning. It was observed that adsorption energy of binders on goethite surface had weak dependence on number of hydrogen bonds between them. With this favorable interaction in mind, a library containing 64 organic binders was constructed and adsorption energy of 30 of these binders was computed using molecular dynamics, followed by training of a linear regression model, which was then used to predict the adsorption energy of rest of the binders in the library. It was found that the introduction of –CH 2 CH 2 OH at R2 position resulted in statistically significant higher adsorption energy. Binder34 and Binder44 were identified as viable candidates for both goethite and hematite ore pelletization and adsorption of their n-mers on goethite and hematite surfaces was also quantified. Designing of Organic binders for Low-grade iron ore palletization using molecular dynamics simulations, quantum chemical calculations and machine learning methods. By using the quantum chemical data, the machine learning model was built and trained followed by the prediction of most probable adsorbed organic binders from a binders library. [Display omitted] • Organic polymers based on sugars used as binders for goethite ore pelletization. • A library of binders was constructed and its adsorption on Goethite was quantified. • Polar group –CH 2 CH 2 OH at R2 position resulted in higher adsorption energy. • Binder34 and Binder44 were identified as candidates for goethite ore pelletization. [ABSTRACT FROM AUTHOR]

Reactive force field (ReaxFF) based molecular dynamics simulations were performed to study the interaction nature of grafted dextrin with hematite. Nature of interaction further explained by doing periodic density functional theory (DFT) calculations. It was observed that in presence of moisture, the polymer adsorbed on the hematite surface via hydrogen bond formation mediated by water. Upon heating, the interfacial water evaporated and boding interactions with the surface was were established. The oxygens present in the polymer backbone also took part in bonding interactions in addition to −COOH, −OH and −COOCH3 functional groups. The binding energies were estimated as −35.8 (Dextrin), −42.6 (Dextrin grafted with polyacrylic acid) and −38.0 kcal/mol (Dextrin grafted with polyacrylic acid and poly (methyl acrylate)) which indicated chemisorption and effect of molecular weight. Grafted dextrin, having higher molecular weight exhibited stronger interaction and it is anticipated that it will have better thermal stability. Binding energy estimated from DFT calculations as −34.8 kcal/mol. DFT charge density difference calculation showed that the oxygen present in the ring polymer structure also interacted with Fe d‐orbitals. [ABSTRACT FROM AUTHOR]

A novel sulfated hierarchically porous geopolymer catalyst for the oxidation of dibenzothiophene was prepared through sequential treatment with desilication, ion-exchange and sulfation techniques. Desilication and ion-exchange treatments were aimed at the creation of hierarchical porosity and controlling the surface area of the geopolymer, while sulfation treatment was primarily done to enhance the acidity of the hierarchically porous geopolymer. The properties of the catalyst obtained after the modifications was studied by BET, NH3-TPD, SEM, TEM, XRD, FTIR and XRF analyses. As a result of the proposed sequential treatment, the activity of the geopolymer towards the oxidation of dibenzothiophene was profoundly increased and reflected in the enhanced conversion from 14 to 85%. A plausible electronic mechanism proposed for the reaction accentuated that the reaction might take place in two stages: the formation of sulfated geopolymer peroxo complex as the active catalyst and nucleophilic attack by dibenzothiophene over the peroxo complex to form the product, both were elaborated with suitable kinetic model. The interaction between dibenzothiophene and peroxo complex was considered to be of primary concern, based on which, Langmuir–Hinshelwood kinetic model was developed. Effective regeneration upto three cycles emphasized its potential to be exploited as an efficient catalyst for oxidative desulfurization. [ABSTRACT FROM AUTHOR]

• Molecular level presentation of coal. • Molecular structure development using machine learning (ML) and density functional theory (DFT) methods. • ReaxFF MD simulations to understand thermal decomposition of coal. • DFT IR spectra. • Characterization of coal using FTIR and NMR techniques. The nature of interaction between coal surface and reagent affects fine coal flotation yield. Hence, it is crucial to understand the nature of coal surface to improve flotation yield. Therefore, determination of coal surface at the molecular level is important to optimize the flotation performance. But coal is a complex material, and its molecular presentations depend highly on its geographical origin. In this work, various experimental techniques such as ultimate analysis, proximate analysis, TGA, FTIR and solid state 13C NMR were used to characterize the structure of low-rank Indian coal. The data extracted from these experiments were then used to develop molecular level presentation of coal using machine learning (ML) and DFT. Five stable molecular level structures were proposed for this Indian coal. DFT calculated FTIR spectra matches reasonably with the experimental FTIR data. Finally, a 3D model of the coal sample was developed, and reactive force field (ReaxFF) molecular dynamics simulations were performed for thermal decomposition analysis. [Display omitted] [ABSTRACT FROM AUTHOR]

In this work, we have synthesized two new [C, C] cyclometalated Ir(III)–NHC complexes, [IrCp*(C∧C:NHC)Br](1a,b), [Cp* = pentamethylcyclopentadienyl; NHC = (2-flurobenzyl)-1-(4-methoxyphenyl)-1H-imidazoline-2-ylidene (a); (2-flurobenzyl)-1-(4-formylphenyl)-1H-imidazoline-2-ylidene (b)] via intramolecular C–H bond activation. The molecular structure of complex 1a was determined by X-ray single crystal analysis. The catalytic potentials of the complexes were explored for acceptorless dehydrogenation of alcohols to carboxylic acids with concomitant hydrogen gas evolution. Under similar experimental conditions, complex 1a was found to be slightly more efficient than complex 1b. Using 0.1 mol% of complex 1a, good-to-excellent yields of carboxylic acids/carboxylates have been obtained for a wide range of alcohols, both aliphatic and aromatic, including those involving heterocycles, in a short reaction time with a low loading of catalyst. Remarkably, our method can produce benzoic acid from benzyl alcohol on a gram scale with a catalyst-to-substrate ratio as low as 1 : 5000 and exhibit a TON of 4550. Furthermore, the catalyst could be recycled at least three times without losing its activity. A mechanism has been proposed based on controlled experiments and in situ NMR study. [ABSTRACT FROM AUTHOR]

Refractoriness of chrome minerals imposes challenges during chrome ore pelletization process. This study is conducted to find suitable additives to improve chrome ore pelletization and pellet properties. Two types of additives (carbonaceous heating additives and binding fluxes) have been explored to improve pellet induration in pre-heating and elevated temperature zone of a shaft furnace. Ten different types of carbonaceous heating additives (rice husk powder, coke fines, anthracite coal, Indian coal, South African coal, Indonesian coal, graphite powder, carbon soot, pet coke, charcoal) were tested and found that rice husk powder and carbon soot are the most effective additives to improve pellet properties in the shaft furnace pre-heating zone. Rice husk dosing improves pellet strength by 31% (31.76 to 41.90 kgf) in the pre-heating zone which helps pellets to maintain their shape and size, this in terms improve the pellet bed permeability and gas flow during sintering. Seven diverse types of binding fluxes (Dolomite, Magnesium-chromite fines, Magnesium-carbon fines, MgCl2, Na3AlF6, MgO powder, and DRI-additive) were studied in the lab. Cryolite dosing between 0.25% to 2% in pellet mix improved pellet compressive strength by 190% (63 to184 kgf) and reduced pellet swelling by 30%. A pellet mix which contained 95% ore fines, 2% bentonite, 2% rice husk powder, 1% cryolite and 14% moisture has been identified as an optimized pellet mix for producing pellets with 197 kgf/pellet compressive strength. The pellets produced using optimized pellet mix also showed superior metallurgical properties during smelting reduction. It can improve the overall plant productivity economically. [ABSTRACT FROM AUTHOR]

This paper has focused on transformation of bibliographic data to linked open data (LOD) as RDF(Resource Description Framework) triple model with integration of external resources. Library & Information centres and knowledge centres deal with various types of databases like bibliographic databases, full text databases, archival databases, statistical databases, CD/DVD ROM databases and more. Presently, web technology changes storing, processing, and disseminating services rapidly. The semantic web technology is an advance technology of web platform which provides structured data on web for describing and retrieving by the organization or institutions. It may provide more information from other external resources to the users. The main objective of this paper is transformation of library bibliographic data, based on MARC21, to RDF triple format as LOD with enrichment of external LOD dataset. External resources like OpenLibrary, VIAF, Wikidata, DBpedia, GeoNames etc. We have proposed a Workflow model (Figure-1) to visualize details steps, activities, components for transforming bibliographic data to LOD dataset. The methodology of this work includes the various methods and steps for conducting such research work. Here we have used an open source tool OpenRefine (version 3.2), formally it is known as GoogleRefine. The OpenRefine tool is used for managing and organizing the messy data with different attribute like rowcolumn manipulation, reconciliation manipulation, different format manipulation like XML, JSON, N-Triple, RDF etc. The OpenRefine tool has played the various roles for the research work such as insertion of URI column, link generation, reconciliation data for external sources, conversion of source format to RDF format etc. After conversion of whole bibliographic data into RDF triple format as considerable LOD dataset. At the production page we may find a RDF file of bibliographic data. This LOD dataset may further be used by the organizations or institutions for their advanced bibliographic service. [ABSTRACT FROM AUTHOR]

A series of chiral alternating copolymers based on glycyl-glycine attached styrenic monomer (VG) and alanyl-alanine tethered maleimide (MA) are synthesized through reversible addition-fragmentation chain transfer (RAFT) polymerization. The alternating sequential arrangement of the two monomers along the synthetic copolymer chain is systematically established through 1H and 13C NMR spectroscopic investigation. The thermal as well as chiroptical characteristics of the copolymers are also studied. Interestingly, the copolymers show unusual luminescence characteristics in different organic solvents under UV light irradiation, whereas in the solid state they emit blue, green and red fluorescence as witnessed from the corresponding fluorescence microscopy micrographs. Furthermore, after successful Boc group removal, the deprotected copolymers show pH-dependent solubility variation in aqueous solution with an almost invariant transition pH with respect to varying chain lengths of the polymers. Thus, the strategy reported herein offers a notable direction to fabricate various dipeptide-based sequence-controlled polymers with promising applications. [ABSTRACT FROM AUTHOR]

The library is not only a storehouse of knowledge; it is also an essential component of the teaching and learning process of an academic Institute. It is a well-established truth that the Library is the center of any educational setting. While classroom teaching offers a glimpse of knowledge, the libraries disseminate a vast variety of knowledge, which is required to attain mental heights. Libraries supplement the educational work of classrooms and lift forward the ideals of education. The use of existing knowledge is as important as the discovery of new knowledge. The purpose of this paper is to highlight the various services provided by the B. C. Roy Memorial Library of IIM Calcutta, Kolkata, W.B. Library as the learning resource centre and occupies a unique place in the academic and research activities of the Institute. Over time, due to the impact of Information Technology, drastic changes have been taken place in terms of collection, organization, and the way and nature of service it provides. It is seen the usage of library resources has been increased manifolds after implementing ITbased services. [ABSTRACT FROM AUTHOR]

The field experiments were conducted at Agricultural farm of the Institute during 2014-15 and 2015-16 to study growth, yield attributes, yield and economics of rice as influenced by rice-based cropping systems. The experiment, consisted of ten treatments, was laid out in Randomised Block Design with each treatment replicated thrice. Growth attributes of rice were influenced significantly by diversification of crops in various rice-based cropping systems. Rice in rice- lentil-elephant foot yam showed highest growth attributes followed by rice- frenchbean-baby corn and rice-yellow sarson-greengram systems though they were at par with each other. Rice in rice-potato-greengram system exhibited highest number of paniclesm-2 and filled grains panicle-1 followed by rice- lentil-elephant footyam and rice-frenchbean-baby corn system being at par with each other. Highest grain and straw yield of rice was achieved from rice- potato-greengram (4.81 and 6.12 t ha-1, respectively) followed by rice-yellow sarson-greengram and rice-lentil-okra. Gross return, net return and return per rupee investment in rice were not significant during first year but significant response was found during second year where highest gross return, net return and return per rupee investment was found from rice-potato-green gram system (86,417 ha-1, 52,099 ha-1 and 2.20, respectively) followed by rice- lentil-okra and rice-yellow sarson-greengram though they were at par with each other. Inclusion of legume crops in rice-based cropping systems enhanced grain and straw yield of rice resulting in higher return from the system. [ABSTRACT FROM AUTHOR]

The thiophene extraction from model fuel by using N-methyl-2-pyrrolidone [NMP], dimethylformamide [DMF] and ethylene glycol [EG] as solvents had been carried out at atmospheric pressure. It is found that NMP showed the best performance with 98% removal of thiophene for 1 h. A detail parametric study was performed to investigate the effect of different process parameters on the extraction of thiophene by using NMP as the solvent. Finally Box-Behnken design (BBD) explores the relationship between output, sulfur removal efficiency and inputs parameters like time, temperature and solvent to model fuel volume ratio. [ABSTRACT FROM AUTHOR]

A new air and moisture stable PEPPSI (PEPPSI: pyridine-enhanced pre-catalyst preparation, stabilisation, and initiation) themed palladium N-heterocyclic carbene (NHC) complex [Pd(L)Br2(Py)] (1) [L: 2-flurobenzyl)-1-(4-methoxyphenyl)-1H-imidazolline-2-ylidene] was synthesized and characterized. The structure of complex 1 was determined by X-ray single-crystal analysis. The palladium center in 1 adopted a square planar geometry with carbene and pyridine ligands occupying the mutual trans position. The complex 1 was employed to catalyze the Mizoroki-Heck cross-coupling reactions of aryl bromides/iodides with styrene in water. To the best of our knowledge, this is the first report where a Pd-PEPPSI catalyst was successfully employed in aqueous-phase Mizoroki-Heck reaction. Good to excellent yields of cross-coupling products were obtained with a range of representative aryl bromides/iodides under relatively mild conditions (100 °C, 1 mol% of 1). A new palladium PEPPSI complex was synthesized, characterized and evaluated as catalyst for the Mizoroki-Heck reaction in aqueous medium. Both electron-donating and electron-withdrawing aryl halides (bromides and iodides) reacted with styrene to give corresponding coupling products in moderate to excellent yields. [ABSTRACT FROM AUTHOR]

High temperature quantum chemical molecular dynamics simulations on the polycyclic aromatic hydrocarbon (PAH) formation during combustion of benzene were performed using the density-functional tight-binding (DFTB) method. Systems with varying H/C of 0.8, 0.6, 0.4, and 0.2 and temperatures of Tn=2500 K and Tn=3000 K were employed for the study of the PAH formation and growth mechanism, and trajectories were analyzed by recording average C:H compositions, common elementary reactions and molecular species, ring count, and other characteristic quantities as functions of time. We found that at H/C=0.8 mostly short polyacetylenic hydrocarbons were formed, and no significant PAH growth was found. At lower H/C ratio, longer polyacetylenic chains started to form and new five- and six-membered rings were created due to chain entanglement. Significant PAH growth forming only pericondensed PAHs was observed at lower H/C ratios of 0.4 and 0.2. In addition, smaller hydrocarbon species, such as C2H2, C2H, and C2, are constantly produced by fragmentation of hydrocarbons (unimolecular reactions) and remain common species, although they are simultaneously consumed by the H-abstraction-C2H2-addition growth mechanism. Hydrogen is found to have a clear inhibitive effect on PAH and carbon cluster growth in general, in agreement with recent experimental observations. [ABSTRACT FROM AUTHOR]

• DFT study of corrosion protection performances of organogermane precursors for ZnO substrate. • Organogermane molecules formed multiple bonding interactions with (ZnO) 12 cluster. • High adsorption energies (∼50 kcal/mol) obtained for functionalized organogermanes compared to that (∼27 kcal/mol) of non-functionalized. • Presence of heteroatoms, like O/N/S in organogermane molecules assisted in formations of chemical bonds with Zn atoms of the substrate. • Germanium-based corrosion protective coating on GI steel substrate. Germanium (Ge)-based thin film through sol-gel coating technology can be a suitable alternative like their silane analogue to develop metal-free and solvent-free corrosion protective coating with additional functional properties for galvanized (GI) steel. In this work, adsorption mechanism and reactivity of functionalized (by functional groups such as epoxy, amine, and mercapto) and non-functionalized - organogermane alkoxides towards GI steel substrate were investigated using density functional theory (DFT), where (ZnO) 12 cluster was adopted as model of GI steel and other ZnO substrate. Calculated global reactivity parameters of organogermanes suggested that functionalized organogermanes were more efficient for corrosion protection of ZnO substrate. Adsorption process was exothermic and free energy change (Δ G) in adsorption process lied between 27.4 kcal/mol and 51.9 kcal/mol which confirmed adsorption potentiality of organogermanes. Adsorptions of functionalized organogermanes were much more exothermic (∼50 kcal/mol) than that of non-functionalized one (∼27 kcal/mol) which suggested chemisorption of functional organogermane molecules. Geometry, MOs, and charge analyses of adsorbed structures further supported that all functional organogermanes chemisorbed on the GI steel. Multiple bonds were formed at the interface. Presence of heteroatoms, like O/N/S in organogermane molecules assisted in formations of chemical bonds with Zn atoms of the substrate. Ge center took hypervalency and formed non-classical Ge-O bond with O atom of the substrate in all functional organogermanes. Formation of O H—O hydrogen bonds were also observed at the interface. These Ge-O and O H—O bond formation played key roles in the interface and manifested stronger interaction, making functional organogermane alkoxides suitable for coating applications. Stronger adsorptions of functional organogermanes could be interpreted in terms of higher highest occupied molecular orbital (HOMO) energies and lower HOMO-lowest occupied molecular orbital (LUMO) gap values for functionalized organogermanes which favored the electron donation from the HOMOs of functionalized organogermanes to the LUMOs of (ZnO) 12 cluster. [Display omitted] [ABSTRACT FROM AUTHOR]

Excited-state geometries and electronic spectra of butadiene, acrolein, and glyoxal have been investigated by the symmetry adapted cluster configuration interaction (SAC-CI) method in their s-trans conformation. Valence and Rydberg states below the ionization threshold have been precisely calculated with sufficiently flexible basis sets. Vertical and adiabatic excitation energies were well reproduced and the detailed assignments were given taking account of the second moments. The deviations of the vertical excitation energies from the experiment were less than 0.3 eV for all cases. The SAC-CI geometry optimization has been applied to some valence and Rydberg excited states of these molecules in the planar structure. The optimized ground- and excited-state geometries agree well with the available experimental values; deviations lie within 0.03 Å and 0.7° for the bond lengths and angles, respectively. The force acting on the nuclei caused by the excitations has been discussed in detail by calculating the SAC-CI electron density difference between the ground and excited states; the geometry relaxation was well interpreted with the electrostatic force theory. In Rydberg excitations, geometry changes were also noticed. Doubly excited states (so-called 2 1Ag states) were investigated by the SAC-CI general-R method considering up to quadruple excitations. The characteristic geometrical changes and large energetic relaxations were predicted for these states. [ABSTRACT FROM AUTHOR]

Progress of every profession, academic discipline, and society at large rides on the back of research and development. Research generates new information and knowledge. It is a standardized process of identifying the problem, collecting data or evidence, tabulating data and its analysis, drawing inference and establishing new facts in the form of information. Therefore, research is a long process and a lot of time is required to complete research work. The information and communication technology, especially the internet and the www, descended from the cyberspace help researchers a lot in this regards. There are a lot of web-based programmes, tools, sites, and open source initiatives that help researchers to make the process more efficient and organized and thus save the time of the researchers too. The research domain of library and information science has witnessed a rapid increase in the use of web-based tools in recent years. This paper addresses some web-based tools, websites, open-source initiatives that would help academic community especially research scholars immensely to customize search engines, to search relevant documents of his/her subject interest, to organize and manage citations, to assemble topic related articles and other documents in one place, to get access to open access & other e-resources and many more. [ABSTRACT FROM AUTHOR]

Highlights • Preparation of nano-Ag/TiO 2 catalyst from silver nitrate and Tulsi leaf extract. • Characterisation and application of Ag/TiO 2 catalyst in thiophene oxidation. • Both pseudo-homogeneous and heterogeneous rate models are proposed. • Endothermicity of the reaction was established by thermodynamic analysis. • Surface reaction is found to be the rate limiting step following L-H kinetic model. Abstract The present research work describes the preparation of silver nanoparticles from silver nitrate, and Tulsi (Ocimum tenuiflorum) leaf extract, impregnation on titanium dioxide (TiO 2) and evaluation of the catalytic activity of this nano silver impregnated TiO 2 in the oxidation reaction of thiophene. Tertiary-butyl hydroperoxide was used as an oxidant in the reaction. The catalyst was characterized by BET, SEM, XRF, TEM, UV–Vis spectroscopy, XPS and TPR. The effect of process parameters such as speed of agitation, catalyst weight, oxidant to sulfur mole ratio, silver loading in the catalyst and temperature on the oxidation reaction was studied. Both pseudo-homogeneous and heterogeneous kinetic models were considered and applied for the result. The pseudo-homogeneous form of rate equation shows the reaction follows second order kinetics and is endothermic. Langmuir-Hinshelwood kinetic model is proposed, considering the reaction as a heterogeneous one with solid catalyst and found that surface reaction is the rate controlling step. This model is well fitted with experimental data. [ABSTRACT FROM AUTHOR]

[Display omitted] • Supercritical, ultrasound and microwave-assisted deasphalting were investigated for HFO. • Microwave-assisted solvent deasphalting lowers solvent use requirements. • Microwave causes a higher degree of resin solubilization and asphaltene aggregation in HFO. • Central composite design and artificial neural network models agree with experimental data. • Deasphalting reduces the viscosity of HFO along with a significant drop in S and N contents. As petroleum recovery has progressed historically, the portion of heavier crudes and bottom of the barrel residues from the refining process has increased. These crudes are challenging to process, leaving vacuum residues with large fractions of ash and refractory sulfur due to high asphaltene content. Asphaltenes are known to form coke in catalytic upgraders and deactivate refining catalysts. Asphaltenes, which are present in significant amounts in heavy crudes, are the cause of reduction of combustion efficiency, clogging of refinery pipes, and particulate matter emissions. Asphaltenes can be removed from heavy crudes by solvent deasphalting. But the requirement of a high solvent to oil ratio limits its commercial viability. To lower the requirement of solvent, this study investigates deasphalting of heavy fuel oil (HFO) with n-heptane, n-hexane, and n-pentane by microwave-assisted, ultrasound-assisted, and supercritical solvent deasphalting methods. Among the different methods investigated, the microwave-assisted method was found to be more efficient and removed 88 and 80 wt% of asphaltenes from HFO with heptane and hexane, respectively. Microwave irradiation selectively heats asphaltenes in microwave transparent non-polar solvents and increases the degree of collision of asphaltenes for aggregation and thus precipitation. Besides, resins are readily solubilized by the solvent under microwave heating and thus they are unable to act as peptizing agents of asphaltenes. The optimization of process parameters such as solvent to HFO ratio, microwave power, and holding time was investigated for microwave-assisted deasphalting using Central Composite Design (CCD) and artificial neural network (ANN). The optimum removal of asphaltene was observed when the solvent to HFO ratio, microwave power, and holding time were kept at 3, 150 W, and 20 min, respectively. Deasphalting also significantly improved the quality of HFO by dropping the viscosity along with the sulfur and nitrogen contents of HFO. The outcomes of this study are significant for the petrochemical industry as potentially improved crude oil processing with lower solvent to HFO ratios can be achieved in a more effective, economical manner using microwave assistance. [ABSTRACT FROM AUTHOR]

In this article, we consider the uniqueness problem of the non linear differential polynomial fn(z)(f(z) - 1)mP[f], where f(z) is a transcendental meromorphic function. With the concept of weakly weighted sharing and relaxed weighted sharing we obtain some results which extend and improve some results due to the present first author [Korean J. Math., 28(2020), No. 4, 871-888]. [ABSTRACT FROM AUTHOR]

Nano hydroxyapatite (Hap) was synthesized by green route using carrot peal extract and used as catalyst in thiophene oxidation reaction. The catalyst was characterized with TEM, XRD, XRF, SEM, BET and DLS size analysis. The particle size was found to be in the nano range. The highest conversion for thiophene oxidation was observed as 65%. Titanium and molybdenum were impregnated in nano Hap to investigate any further improvement of its efficiency towards the oxidation and a substantial increase in conversion of thiophene, 82%, was observed after impregnation. The influence of different process parameters on oxidation of thiophene using Ti-Mo impregnated nano Hap as catalyst was investigated. The metal-impregnated catalyst was characterized with FTIR, SEM, XRD, EDS analysis before and after the reaction. Langmuir-Hinshelwood (LH) model was proposed to explain the kinetics of the reaction. [ABSTRACT FROM AUTHOR]

A phosphine, base and additive free cross-coupling of arylboronic acid is reported via C–O bond cleavage of acetic anhydride using a switchable ferrocene functionalized n-heterocyclic carbene (NHC) palladium complex. The novel redox active catalytic system afforded the corresponding arylketones with good to excellent yields. [ABSTRACT FROM AUTHOR]

Intermolecular energy transfer for the vibrationally excited propylbenzene cation (C9H12+) in a helium bath was studied with chemical dynamics simulations. The bond energy bond order relationship and electronic structure calculations were used to develop an intramolecular potential for C9H12+. Spin component scaled MP2/6-311++G** calculations were used to develop an intermolecular potential for He + C9H12+. The He + He intermolecular potential was determined from a previous explicitly correlated Gaussian electronic structure calculation. For the simulations, C9H12+ was prepared with a 100.1 kcal/mol excitation energy to compare with experiment. The average energy transfer from C9H12+, ⟨ΔEc⟩, decreased as C9H12+ was vibrationally relaxed and for the initial excitation energy ⟨ΔEc⟩ = 0.64 kcal/mol. This result agrees well with the experimental ⟨ΔEc⟩ value of 0.51 ± 0.26 kcal/mol for collisions of He with the ethylbenzene cation. The ⟨ΔEc⟩ value found for He + C9H12+ collisions is compared with reported values of ⟨ΔEc⟩ for He colliding with other molecules. [ABSTRACT FROM AUTHOR]

A one-dimensional nanostructure with sp3-hybridized carbon atoms, namely, poly[5]asterane (PA), is predicted by means of electronic structure calculations and reactive molecular dynamics simulations. Thermochemical analysis based on homodesmotic reactions showed that the formation of poly[5]asterane is more favorable than that of polytriangulane and comparable to that of polytwistane. A plane-wave DFT approach gave a computed Young's modulus of about 0.84 TPa, which is quite promising and comparable to those of other sp3-hybridized nanothreads. Simulations of the desorption of hydrogen atoms from PA showed a high activation energy ( Ea≈52 kcal mol−1), which again indicates substantial chemical stability. Interestingly, PA was shown to exhibit auxetic behavior (negative Poisson's ratio). Thus, PA is advocated as a new mechanically and chemically stable nanothread with exotic auxetic behavior. [ABSTRACT FROM AUTHOR]

Thiophene oxidation with hydrogen peroxide was studied with tetrabutylammonium bromide, phenyltrimethylammonium tribromide, ethyltriphenylphosphonium bromide, benzyltrimethylammonium tribromide, tetrapropylammonium bromide, tetrabutylammonium hydrogensulphate, and 18-crown-6-ether as phase transfer catalysts (PTC) under ultrasound. Highest conversion (82.59%) was achieved with benzyltrimethylammonium tribromide at 1,200 rpm and 30 kHz frequency. The effect of parameters such as oxidant-to-sulphur mole ratio, intensity of ultrasound, stirrer speed, catalyst amount, and operating temperature on oxidation was explored by using benzyltrimethylammonium tribromide. Central composite design was chosen for optimization of conversion using temperature, catalyst loading, and molar ratio. The pseudo first-order kinetics with apparent activation energy of 79.55 kJ/mol was established. [ABSTRACT FROM PUBLISHER]

Radio frequency magnetron sputtering technique has been used to prepare n- n isotype heterostructure of CdO-ZnO thin film on glass substrate. The energy band structure analysis shows the formation of charge accumulation and charge depletion region created near the interface of CdO-ZnO n- n isotype heterostrucure which leads to the formation of a junction capacitance. The impedance spectroscopic studies of CdO-ZnO isotype heterostructure show an excellent dispersion in the impedance spectra as observed in the Nyquist plot depending on applied DC bias voltage. The frequency response of impedances has been explained from band structure and equivalent electrical circuit model of the heterostructure. These studies will be highly significant in exploring the possibility of application of such isotype interfaces in optimizing the functionality of organic and inorganic electronic devices and solar cells. [ABSTRACT FROM AUTHOR]

ABSTRACT In this report, we have synthesized organic/inorganic hybrid peptide-poly(ɛ-caprolactone) (PCL) conjugates via ring opening polymerization (ROP) of ɛ-caprolactone (CL) in the presence of two sequence defined peptide initiators, namely POSS-Leu-Aib-Leu-NH2 (POSS: polyhedral oligomeric silsesquioxane; Leu: Leucine; Aib: α-aminoisobutyric acid) and OMe-Leu-Aib-Leu-NH2. Covalent attachment of peptide segments with the PCLs were examined by 1H and 29Si NMR spectroscopy, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and FTIR spectroscopy. Supramolecular inclusion complexations of synthesized peptide-PCL conjugates with α-cyclodextrin (α-CyD) were studied to understand the effect of POSS/OMe-peptide moieties at the PCL chain ends. Inclusion complexation of peptide-PCL conjugates with α-CyD produced linear polypseudorotaxane, confirmed by 1H NMR, FTIR, powder X-ray diffraction (PXRD), polarized optical microscopy (POM) and differential scanning calorimetry (DSC). Extent of α-CyD threading onto the hybrid peptide-PCL conjugated polymers is less than that of α-CyD threaded onto the linear PCL. Thus, PCL chains were not fully covered by the host α-CyD molecules due to the bulky POSS/OMe-peptide moieties connected with the one edge of the PCL chains. PXRD experiment reveals channel like structures by the synthesized inclusion complexes (ICs). Spherulitic morphologies of POSS/OMe-peptide-PCL conjugates were fully destroyed after inclusion complexation with α-CyD and tiny nanoobjects were produced. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 3643-3651. [ABSTRACT FROM AUTHOR]

Rapid developments of soft polymeric materials have inspired for a better understanding of their tribological characteristics. The tribological behavior of polymethylmethacrylate (PMMA) against 1H,1H,2H,2H-perfluorodecyltrichlorosilane [CF 3 (CF 2 ) 7 (CH 2 ) 2 SiCl 3 ] (FDTS) coated silicon (Si) substrate (F-Si) as a function of the applied-temperature, load and sliding velocity was studied and reported in this paper. It was observed that friction coefficient vs. applied-temperature curves follow the viscoelastic behavior of PMMA, which indicates that molecular relaxation of PMMA is the dominating factor of its tribological properties at temperature below its glass transition temperature ( T g ). Furthermore, consistent shifts of friction coefficient vs. temperature curves toward low temperatures with increase in load in addition to sliding velocity further signified, the importance of friction induced-temperature on the tribological properties of PMMA. [ABSTRACT FROM AUTHOR]

Recently, polymer drug conjugates (PDCs) have attracted considerable attention in the treatment of cancer. In this work, a simple strategy has been developed to make PDCs of an antitumor alkylating agent, chlorambucil, using a biocompatible disulphide linker. Chlorambucil-based chain transfer agent was used to prepare various homopolymers and block copolymers in a controlled fashion via reversible addition-fragmentation chain transfer polymerization. Chlorambucil conjugated block copolymer, poly(polyethylene glycol monomethyl ether methacrylate)-b-poly(methyl methacrylate), formed nanoaggregates in aqueous solutions, which are characterized by dynamic light scattering and field emission-scanning electron microscopy. Finally, the simplicity of the design is exemplified by performing a release study of chlorambucil under reducing condition by using D,L-dithiothreitol. [ABSTRACT FROM AUTHOR]

Background Hypoxia is a critical secondary injury mechanism in traumatic brain injury (TBI), and early intervention to alleviate post-TBI hypoxia may be beneficial. NVX-108, a dodecafluoropentane perfluorocarbon, was screened for its ability to increase brain tissue oxygen tension (PbtO 2 ) when administered soon after TBI. Methods Ketamine-acepromazine anesthetized rats ventilated with 40% oxygen underwent moderate controlled cortical impact (CCI)-TBI at time 0 (T0). Rats received either no treatment (NON, n =8) or 0.5 ml/kg intravenous (IV) NVX-108 (NVX, n =9) at T15 (15 min after TBI) and T75. Results Baseline cortical PbtO 2 was 28±3 mm Hg and CCI-TBI resulted in a 46±6% reduction in PbtO 2 at T15 ( P <0.001). Significant differences in time-group interactions ( P =0.013) were found when comparing either absolute or percentage change of PbtO 2 to post-injury (mixed-model ANOVA) suggesting that administration of NVX-108 increased PbtO 2 above injury levels while it remained depressed in the NON group. Specifically in the NVX group, PbtO 2 increased to a peak 143% of T15 ( P =0.02) 60 min after completion of NVX-108 injection (T135). Systemic blood pressure was not different between the groups. Conclusion NVX-108 caused an increase in PbtO 2 following CCI-TBI in rats and should be evaluated further as a possible immediate treatment for TBI. [ABSTRACT FROM AUTHOR]

Understanding the atomistic mechanisms of carbon structure formation during templated multi-step carbonization is very important for further optimization of carbon fiber mechanical properties. Here with use of reactive force field molecular dynamics we have elucidated the mechanism driving double-walled carbon nanotube- and graphite nanoparticle-based in situ templating of polyacrylonitrile derived fibers. Depending on carbonization temperature, the mechanism involves either physisorption (physical templating) or chemisorption (chemical templating) of the fiber medium to the template surface. In either case, strong interaction between template and medium leads to the production of aligned structures that are more robust for nanotubes than graphite. We provide a unique analysis of atomistic simulations that enables quantitative comparison of templating results with the relevant electron diffraction data. [ABSTRACT FROM AUTHOR]

Oxidation of thiophene in five different model fuels was studied using TS-1 as catalyst and the influence of different hydrocarbon components in the model fuels on the oxidation and catalyst deactivation were observed in a batch process. The model fuels were prepared by dissolving thiophene at a particular concentration in iso-octane and then adding different types of hydrocarbons such as, a naphthene, a paraffin, an alkane and an aromatic one by one into the basic model fuel. Fresh as well as used catalysts were analyzed in BET, FTIR, XPS and EDS to confirm the deposition of different hydrocarbons as well as sulfur on the catalyst surface. The effects of different process variables on the reaction under catalyst deactivation were noted. Deactivation kinetics for the catalytic reaction was proposed including evaluation of process parameters at different temperatures. The activation energy of the reaction with deactivation of catalyst was found to be 19.13 kJ/mol. [ABSTRACT FROM AUTHOR]

Treatment of [Ru 2 (CO) 4 (CH 3 CN) 6 ](BF 4 ) 2 with 3-methyl-1-(pyridin-2-yl)-imidazolium bromide in the presence of tetrabutylammonium bromide at room temperature in dichloromethane affords a Ru II – N -heterocyclic carbene–carbonyl complex [Ru(py-NHC)(CO) 2 Br 2 ] ( 1 ). Catalyst 1 displays diverse substrate scope for phosphine-free acceptorless coupling between alcohols and amines to amides at low catalyst loading. A Ru II -dihydride/Ru 0 sequence is proposed in the catalytic cycle. [ABSTRACT FROM AUTHOR]

Metalmetal singly-bonded diruthenium complexes, bridged by naphthyridine-functionalized N-heterocyclic carbene (NHC) ligands featuring a hydroxy appendage on the naphthyridine unit, are obtained in a single-pot reaction of [Ru2(CH3COO)2(CO)4] with 1-benzyl-3-(5,7-dimethyl-1,8-naphthyrid-2-yl)imidazolium bromide (BIN ⋅HBr) or 1-isopropyl-3-(5,7-dimethyl-1,8-naphthyrid-2-yl)imidazolium bromide (PIN ⋅HBr), TlBF4, and substituted benzaldehyde containing an electron-withdrawing group. The modified NHC-naphthyridine-hydroxy ligand spans the diruthenium unit in which the NHC carbon and hydroxy oxygen occupy the axial sites. All the synthesized compounds catalyze acceptorless dehydrogenation of alcohols to the corresponding aldehydes in the presence of a catalytic amount of weak base 1,4-diazabicyclo[2.2.2]octane (DABCO). Further, acceptorless dehydrogenative coupling (ADHC) of the alcohol with amines affords the corresponding imine as the sole product. The substrate scope is examined with 1 (BIN, p-nitrobenzaldehyde). A similar complex [Ru2(CO)4(CH3COO)(3-PhBIN)][Br], that is devoid of a hydroxy arm, is significantly less effective for the same reaction. Neutral complex 1 a, obtained by deprotonation of the hydroxy arm in 1, is found to be active for the ADHC of alcohols and amines under base-free conditions. A combination of control experiments, deuterium labeling, kinetic Hammett studies, and DFT calculations support metal-hydroxyl/hydroxide and metal-metal cooperation for alcohol activation and dehydrogenation. The bridging acetate plays a crucial role in allowing β-hydride elimination to occur. The ligand architecture on the diruthenium core causes rapid aldehyde extrusion from the metal coordination sphere, which is responsible for exclusive imine formation. [ABSTRACT FROM AUTHOR]

Highlights: [•] Expeditious cascade protocol for the synthesis of functionalized imidazo[1,2-a]pyridin-3-ols. [•] A three-component Petasis reaction followed by a cascade cyclization. [•] Superior to the existing procedures for the synthesis of imidazo-pyridin-3-ol analogues. [ABSTRACT FROM AUTHOR]

A series of carboxylic acids including amino acids were protected as their corresponding fluorescent ester conjugates by coupling with an environment sensitive fluorophore 9-methylacridine. Photophysical properties of all the ester conjugates along with the protecting group have been investigated. Interestingly, the emission properties of the ester conjugates and 9-methylacridine were found to be highly sensitive to polarity, H-bonding and pH of the environment. Photolysis of all the ester conjugates was carried out using UV light above 360 nm and it was found that in every case the corresponding carboxylic acids were released in high chemical yield. Further, intercalation and the preferred binding mode of acridine-9-methanol and its ester conjugates with DNA were studied. In vitro biological studies revealed that acridine-9-methanol has good biocompatibility, cellular uptake property and cell imaging ability. [ABSTRACT FROM AUTHOR]

Abstract: A mild, cost-effective, and simple three-component Ugi-type reaction using p-toluenesulfinic acid (pTSIA) as the acid catalyst has been developed to synthesize α-amino amides and α-amino amidines. Employing 1equiv of amine used in the reaction generated α-amino amides exclusively, while 2equiv of amines, especially with more nucleophilic aniline such as p-anisidine, yielded the α-amino amidines as the major product. This methodology would be suitable for the synthesis of natural or unnatural amino acids and drug-like amidine analogues. [Copyright &y& Elsevier]

1-(Hydroxyacetyl)pyrene has been introduced as a new fluorescent phototrigger for alcohols and phenols. Alcohols and phenols were protected as their corresponding carbonate esters by coupling with fluorescent phototrigger, 1-(hydroxyacetyl)pyrene. Photophysical studies of caged carbonates showed that they all exhibited strong fluorescence properties. Irradiation of the caged carbonates by visible light (≥410 nm) in aqueous acetonitrile released the corresponding alcohols or phenols in high chemical (95–97%) and quantum (0.17–0.21) yields. The mechanism for the photorelease was proposed based on Stern–Volmer quenching experiments and solvent effect studies. Importantly, 1-(hydroxyacetyl)pyrene showed as a phototrigger for rapid photorelease of the biologically active molecule adenosine. In vitro biological studies revealed that 1-(hydroxyacetyl)pyrene has good biocompatibility, cellular uptake property and cell imaging ability. [ABSTRACT FROM AUTHOR]

SiGe alloy, owing to its high electron and hole mobility, has potential applications in high-speed microelectronic device technology. The optimization of such technology requires the precise determination of Ge concentration in the full range of composition and the understanding and control of the Ge-Si interdiffusion phenomenon. The most appropriate analytical technique with highest detection sensitivity (∼subparts per billion) for measuring elemental concentration is secondary ion mass spectrometry (SIMS). However, strong compositional dependence of secondary ion yield, i.e. 'matrix effect,' has always made SIMS quantification extremely difficult. A procedure for the accurate quantification of Ge concentration in molecular beam epitaxy (MBE)-grown SiGe (0< x<0.72) alloys based on MCs-SIMS approach has been proposed. The 'matrix effect' is shown to be completely suppressed for all Ge concentrations irrespective of impact Cs ion energies. The novel methodology has successfully been applied for direct quantitative composition analysis of Si/Ge multilayer structure. [ABSTRACT FROM AUTHOR]

The carbonization mechanism in polyacrylonitrile (PAN)based carbonnanofibers is studied using ReaxFF molecular dynamics simulations.Simulations are performed at two carbonization temperatures, 2500and 2800 K, and also at two densities, 1.6 and 2.1g/cm3, that are relevant to the experimental carbonizationconditions. The results are analyzed by examining the evolution ofspecies with time, including carbon-only ring structures and gaseousspecies. Formation mechanisms are proposed for species like N2, H2, NH3, and HCN and five-, six-,and seven-membered carbon-only rings, along with polycyclic structures.Interestingly, the formation of five-membered rings follows N2formation and usually occurs as a precursor to six-memberedrings. Elimination mechanisms for the gaseous molecules are foundthat are in agreement with previously proposed mechanisms; however,alternative mechanisms are also proposed. [ABSTRACT FROM AUTHOR]

Abstract: Stainless steel micromold is an alternative of silicon (Si) micromold in the fabrication of polymeric microfluidic devices because of the brittleness and short lifetime of Si mold. High adhesion and friction of stainless steel micromold can cause the distortion of the microstructures of polymeric products. In this work, titanium (Ti), aluminum (Al) and polytetrafluoroethylene (PTFE) were co-sputter deposited on stainless steel micromolds to improve their surface properties. The sputtering power applied to the PTFE target was varied to control the PTFE concentration in the Ti–Al–PTFE coatings, which affected the bonding structure, surface roughness, friction and contact angle of coatings characterized using micro-Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), confocal microscopy, ball-on-disc tribometer and goniometer, respectively. It was observed that the Ti–Al–PTFE coatings were a mixture of carbide, PTFE-like material and amorphous carbon. The surface roughness of coated micromolds decreased with the increase in the PTFE concentration. The Ti–Al–PTFE coating deposited with 50W sputtering power on the PTFE target showed the lowest friction coefficient and surface energy of about 0.17 and 13.1×10−3 N/m, respectively. The coated stainless steel micromolds showed a better replication performance compared to the bare stainless steel micromolds in terms of the quality of polymeric microfluidic devices fabricated using hot embossing process. This work also investigated the coating properties at the sidewalls of the micromold channels and the limitations of the Ti–Al–PTFE coatings for application in hot-embossing. [Copyright &y& Elsevier]

Abstract: Self-assembled monolayer (SAM) coatings of n-octadecyltrichlorosilane [OTS, CH3(CH2)17SiCl3] were deposited on Si micromolds for micro hot-embossing by dipping the Si molds into an anhydrous toluene solvent containing OTS. The coated samples were designated as OTS20, OTS40, OTS60 and OTS80 with respect to deposition time of 20, 40, 60 and 80min to study the effect of deposition time on the coating quality. The composition, surface roughness, friction coefficient, thermal stability and surface energy were measured using X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), nanotribological test and contact angle test, respectively. The thermal stability of the OTS coatings was determined by measuring water contact angle after heating at various temperatures. The XPS and AFM results showed that a prolonged deposition induced a denser and thicker coating structure and more aggregation of OTS, which also increased the surface roughness. A comparative study of the uncoated and OTS60 coated Si micromolds depicted that the OTS coatings had a good potential to improve the surface quality and efficiency of the molds. The OTS60 coating was evaluated after heat treatment at embossing temperature of 130°C for a better understanding of the failure mechanism of the micromolds, which showed that the surface properties of the molds remained unchanged at the embossing temperature. Further characterization of the damaged Si micromolds showed that the peel-off of the coatings after a number of replications was the main reason for the failure of the molds. It was found that periodic re-cleaning of the micromolds and re-deposition of the OTS coatings on the coated Si micromolds could extend the lifetime of the molds up to about 112 embossing operations per mold. [Copyright &y& Elsevier]

Site-directed anchoring of naphthyridine-functionalized N-heterocylic carbene (NHC) is achieved on a metal−metal singly bonded diruthenium(I) platform. Room-temperature treatment of 1-isopropyl-3-(5,7-dimethyl-1,8-naphthyrid-2-yl)imidazolium bromide (PIN·HBr) with Ru2(CH3COO)2(CO)4 in acetonitrile affords the unsupported compound Ru2(CO)4(κ2C2,N1-PIN)2Br2 (1). Judicious alteration in the NHC ligand resulted in the bridged compound Ru2(CO)4(CH3COO)(μ2-κ2C2,N1-BIN)Br (2) (BIN = 1-benzyl-3-(3-phenyl-1,8-naphthyrid-2-yl)imidazol-2-ylidene). X-ray analysis revealed the chelate binding of PIN on each ruthenium at equatorial sites for 1, and the bridge-chelate binding of BIN spanning the diruthenium core for 2. The catalytic utilities of the BArF (tetrakis(3,5-bis(trifluoromethyl)phenyl)borate) salts of these compounds are evaluated toward carbene-transfer reactions from ethyl diazoacetate including aldehyde olefination, cyclopropanation, and X−H (X = O, N) insertions. 1-BArF is clearly shown to be the superior catalyst. DFT calculations are undertaken to understand the influence of NHC binding on the electronic structures of the "Ru2(CO)4" core and to rationalize the lower activity of 2-BArF. [ABSTRACT FROM AUTHOR]

Abstract: Si/Ge multilayer structures have been grown by solid source molecular beam epitaxy (MBE) on Si (111) and (100) substrates and were characterized by high-resolution X-ray diffraction (XRD), atomic force microscopy (AFM), high-depth-resolution secondary ion mass spectroscopy (SIMS) and cross-section high-resolution transmission electron microscopy (HRTEM). A reasonably good agreement has been obtained for layer thickness, interfacial structure and diffusion between SIMS and HRTEM measurements. Epitaxial growth and crystalline nature of the individual layer have been probed using cross-sectional HRTEM and XRD measurements. Surface and interface morphological studies by AFM and HRTEM show island-like growth of both Si and Ge nanostructures. [Copyright &y& Elsevier]