32 research outputs found
USER PRIVACY SELECTION CRITERIA ON PERSONAL DATA IN PUBLIC NETS
A lot of the content discussing websites will grant users to get in the privacy preferences. Our tasks are linked to works based on privacy configuration within crack houses, recommendation systems, additionally to privacy analysis of internet images. We advise an adaptive privacy conjecture system to assist users make privacy settings meant for their images and check out social context, image content, additionally to metadata as achievable indicators of user privacy preference. The recommended plan will handle images of user posted, additionally to factors that influence privacy settings of images for instance impact of social setting additionally to non-public characteristics and role of image content additionally to metadata. The forecasted system will give you comprehensive structure to infer privacy preferences on first step toward information available for any specified user and includes two primary building for instance Adaptive Privacy Conjecture-Social additionally to Core. Adaptive privacy conjecture core will spotlight on analyzing of each and every individual user own images additionally to metadata, while adaptive privacy conjecture-social can have a residential district perspective of privacy techniques for user privacy enhancement
Synthesis and Characterization of Amide Linked Triazolyl Glycolipids as Molecular Hydrogelators and Organogelators
Carbohydrate based small molecular gelators are important classes of compounds which can form useful soft materials with many practical applications. Although many different types of effective gelators have been reported, the rational design of a molecular hydrogelator is still challenging. In this research, we combined the structural features of two classes of monosaccharide based molecular gelators and obtained a new class of glycolipids that can function as molecular gelators. These new compounds were synthesized by introducing a triazole functional group to a protected 2-glucosamine through Cu(i) catalyzed azide/alkyne cycloaddition reaction (CuAAC). A series of eighteen new glycolipids containing 4,6-O-benzylidene acetal protected d-glucosamide and triazole were synthesized and characterized. The self-assembling properties of these compounds were screened in several organic solvents, aqueous solutions, and water. All eighteen compounds are effective molecular gelators for at least one solvent and, more significantly, eleven compounds are hydrogelators with minimum gelation concentrations of 0.15-1.0 wt%. The hydrogels are suitable carriers for sustained release of chloramphenicol, and for the entrapment of toluidine blue dye. These results indicate that the d-glucosamide triazoles are effective templates for small molecular hydrogelators and are useful in designing sugar based soft materials. © 2017 The Royal Society of Chemistry
Unlocking the potential of weberite-type metal fluorides in electrochemical energy storage
Sodium-ion batteries (NIBs) are a front-runner among the alternative battery technologies suggested for substituting the state-of-the-art lithium-ion batteries (LIBs). The specific energy of Na-ion batteries is significantly lower than that of LIBs, which is mainly due to the lower operating potentials and higher molecular weight of sodium insertion cathode materials. To compete with the high energy density of LIBs, high voltage cathode materials are required for NIBs. Here we report a theoretical investigation on weberite-type sodium metal fluorides (SMFs), a new class of high voltage and high energy density materials which are so far unexplored as cathode materials for NIBs. The weberite structure type is highly favorable for sodium-containing transition metal fluorides, with a large variety of transition metal combinations (M, M’) adopting the corresponding Na2MM’F7 structure. A series of known and hypothetical compounds with weberite-type structure were computationally investigated to evaluate their potential as cathode materials for NIBs. Weberite-type SMFs show two-dimensional pathways for Na+ diffusion with surprisingly low activation barriers. The high energy density combined with low diffusion barriers for Na+ makes this type of compounds promising candidates for cathode materials in NIBs
Lithium Insertion into Niobates with Columbite-Type Structure: Interplay between Structure-Composition and Crystallite Size
Design of small hobby CNC milling machine with fixed table
The topic of this work is the design of a small model CNC milling machine with a fixed table for machining wood, plastic, or light alloys (Al, Zn, etc.). It also includes a calculation report and drawing documentation of selected nodes. The beginning of this work consists of an introduction to the issue of milling machines, their distribution and subsequent market analysis. Subsequently, the input parameters are designed on the basis of market analysis and in the last part there is a calculation report, the design of the milling machine itself and a short economic evaluation
Development of solid polymer electrolytes based on poly (ethylene oxide) complexed with 2-trifluoromethyl-4, 5-dicyanoimidazole lithium salt and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid for Li-ion batteries
Ion conducting solid polymer electrolyte films based on polymer poly (ethylene oxide) (PEO) complexed with 2-trifluoromethyl-4, 5-dicyanoimidazole lithium salt and ionic liquid (IL) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide are synthesized using anhydrous acetonitrile as solvent. Prepared electrolyte films are characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC), complex impedance spectroscopy and cyclic voltammetry techniques. Incorporation of IL into the PEO20-LiTDI polymer electrolyte changes different physicochemical properties of these materials. By characterizations, particularly XRD, DSC and ionic conductivity studies, the synthesized SPEs showed decreased crystallinity, melting points and increased ionic conductivity by the introduction of ionic liquid. The 40 wt% of IL doped polymer electrolyte showed an ionic conductivity of the order of 1.78 × 10−4 S/cm at 60°C with better thermal stability. The optimum conducting composition showed very good electrochemical stability window at ambient temperature. These results suggested that the IL-doped polymer electrolyte would be a potential separator in Li-ion batteries
Mechanical Milling Assisted Synthesis and Electrochemical Performance of High Capacity LiFeBO3 for Lithium Batteries
Borate chemistry offers attractive features for iron based polyanionic compounds. For battery applications, lithium iron borate has been proposed as cathode material because it has the lightest polyanionic framework that offers a high theoretical capacity. Moreover, it shows promising characteristics with an element combination that is favorable in terms of sustainability, toxicity, and costs. However, the system is also associated with a challenging chemistry, which is the major reason for the slow progress in its further development as a battery material. The two major challenges in the synthesis of LiFeBO3 are in obtaining phase purity and high electrochemical activity. Herein, we report a facile and scalable synthesis strategy for highly pure and electrochemically active LiFeBO3 by circumventing stability issues related to Fe2+ oxidation state by the right choice of the precursor and experimental conditions. Additionally, we carried out a Mössbauer spectroscopic study of electrochemical charged and charged–discharged LiFeBO3 and reported a lithium diffusion coefficient of 5.56 × 10–14 cm2 s–1 for the first time
Vanadium Oxyfluoride/Few-Layer Graphene Composite as a High-Performance Cathode Material for Lithium Batteries
Metal oxyfluoride
compounds are gathering significant interest as cathode materials
for lithium ion batteries at the moment because of their high theoretical
capacity and resulting high energy density. In this regard, a new
and direct approach is presented to synthesize phase-pure vanadium
oxyfluoride (VO<sub>2</sub>F). The structure of VO<sub>2</sub>F was
identified by Rietveld refinement of the powder X-ray diffraction
(XRD) pattern. It crystallizes in a perovskite-type structure with
disorder of the oxide and fluoride ions. The as-synthesized VO<sub>2</sub>F was tested as a cathode material for lithium ion batteries
after being surface-coated with few-layer graphene. The VO<sub>2</sub>F delivered a first discharge capacity of 254 mA h g<sup>–1</sup> and a reversible capacity of 208 mA h g<sup>–1</sup> at a
rate of C/20 for the first 20 cycles with an average discharge voltage
of 2.84 V, yielding an energy density of 591 W h kg<sup>–1</sup>. Improved rate capability that outperforms the previous report has
been achieved, showing a discharge capacity of 150 mA h g<sup>–1</sup> for 1 C. The structural changes during lithium insertion and extraction
were monitored by ex-situ XRD analysis of the electrodes discharged
and charged to various stages. Lithium insertion results in an irreversible
structural change of the anion lattice from <sup>3</sup>/<sub>4</sub> cubic close packing to hexagonal close packing to accommodate the
inserted lithium ions while keeping the overall space-group symmetry.
For the first time we have revealed a structural change for the ReO<sub>3</sub>-type structure of as-prepared VO<sub>2</sub>F to the RhF<sub>3</sub> structure after lithiation/delithiation, with structural
changes that have not been observed in previous reports. Furthermore,
the new synthetic approach described here would be a platform for
the synthesis of new oxyfluoride compounds