Mechanical properties of bio compatible functional prototypes for joining applications in clinical dentistry

In the presented research, work investigations have been made for mechanical properties of the functional prototypes prepared from biocompatible filament of fused deposition modelling (FDM), comprising of hydroxyapatite (HAp), polypropylene (PP) and polyvinyl chloride (PVC). The functional prototypes will be used in clinical dentistry (mainly for joining application for job-type production activities). The filament has been prepared in house using twin screw extrusion process. For evaluation purpose, standard tensile specimens as per ASTM D-638 have been prepared on FDM. This study highlights the effect of three parameters of FDM (namely: infill percentage, layer thickness and speed of extrusion head) on the mechanical properties (namely: load at peak and load at break). The results of the study suggest that infill density has majorly contributed, 92% on load at peak and 89% for load at break, and deposition speed has very less contribution i.e., 1% towards the mechanical strength of the specimen. Further, the results are supported with thermal analysis using differential scanning calorimeter (DSC), which ensures that the specimen prepared are thermally stable and can be put in for joining applications for job-type production activities in clinical dentistry.     

Plastic crystal-incorporated magnesium ion conducting gel polymer electrolyte for battery application

Studies on a novel composition of magnesium ion conducting gel polymer electrolyte (GPE), comprising a solution of Mg-salt, magnesium trifluoromethanesulfonate (Mg-triflate or \(\hbox {Mg(Tf)}_{2})\) in a plastic crystal succinonitrile (SN), entrapped in a host polymer poly(vinylidenefluoride–hexafluoropropylene) (PVdF–HFP) was reported. Small amount of an ionic liquid, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMITf) was added to stabilize the GPE composition. The electrolyte possesses excellent dimensional integrity in the form of free-standing thick film, which offers the ionic conductivity of \(4 \times 10^{-3} \hbox { S } \hbox {cm}^{-1}\) at room temperature \({\sim }26{^{\circ }}\hbox {C}\). The electrochemical potential window of the electrolyte, observed from the linear sweep voltammetry, is determined to be \({\sim }4.1 \hbox { V}\). The magnesium ion conduction in the GPE film is confirmed from cyclic voltammetry, electrochemical impedance spectroscopy and dc polarization techniques. Different structural, thermal and electrochemical studies demonstrate the promising characteristics of the polymer film, suitable as electrolyte in rechargeable magnesium batteries. The potential of the GPE as electrolyte/separator was ascertained by fabricating a prototype magnesium battery of the configuration Mg:graphite composite \(\hbox {anode}/\hbox {GPE}/\hbox {MnO}_{2}\)-cathode. The specific discharge capacity of \(40 \hbox { mAh g}^{-1}\) (with respect to the \(\hbox {MnO}_{2}\) cathode material) was obtained at the first discharge. The cell shows charge–discharge performance for eight cycles with a substantial fading in capacity.     

Effect of heat-input and cooling-time on bead characteristics in SAW

Load-carrying capacity of weld joints could be identified by its shape and size where weld bead geometry and shape relationship parameters are of utmost importance. Heat input and preheating temperature together can control the cooling time of weld, which in turn determines the weld microstructure and its mechanical properties. To control the shape and geometry of weld bead, it is necessary to understand its relationship with cooling time. In present work, preheating temperature is used as process variable along with heat input varying parameters for understanding their effects on weld bead geometry and shape relationship parameters using submerged arc welding process on high-strength low alloy pipeline steel. The experimental investigation was then analyzed by using the mathematical modeling in context with response surface methodology. The mathematical model predicts the influential dependency of cooling time on the preheating temperature than the other weld process parameters. The associated effects in relation to the process parameters have been discussed and analyzed in the present study.     

Vortex Matter in Highly Strained Nb$$_{}$$Zr$$_{25}$$25: Analogy with Viscous Flow of Disordered Solids

We present the results of magnetization and magneto-transport measurements in the superconducting state of an as-cast Nb\(_{75}\)Zr\(_{25}\) alloy. We also report the microstructure of our sample at various length scales by using optical, scanning electron and transmission electron microscopies. The information of microstructure is used to understand the flux pinning properties in the superconducting state within the framework of collective pinning. The magneto-transport measurements show a non-Arrhenius behaviour of the temperature- and field-dependent resistivity across the resistive transition and is understood in terms of a model for viscous flow of disordered solids which is popularly known as the ‘shoving model’. The activation energy for flux flow is assumed to be mainly the elastic energy stored in the flux-line lattice. The scaling of pinning force density indicates the presence of two pinning mechanisms of different origins. The elastic constants of the flux-line lattice are used to estimate the length scale of vortex lattice movement, or the volume displaced by the flux-line lattice. It appears that the vortex lattice displacement estimated from elastic energy considerations is of the same order of magnitude as that of the flux bundle hopping length during flux flow. Our results could provide possible directions for establishing a framework where vortex matter and glass-forming liquids or amorphous solids can be treated in a similar manner for understanding the phenomenon of viscous flow in disordered solids or more generally the pinning and depinning properties of elastic manifolds in random media. It is likely that the vortex molasses scenario is more suited to explain the vortex dynamics in conventional low-T\(_C\) superconductors.     

An integrated framework for software vulnerability detection,analysis and mitigation: an autonomic system

Nowadays, the number of software vulnerabilities incidents and the loss due to occurrence of software vulnerabilities are growing exponentially. The current existing security strategies, the vulnerability detection and remediating approaches are not intelligent, automated, self-managed and not competent to combat against the vulnerabilities and security threats, and to provide secured self-managed software environment to the organizations. Hence, there is a strong need to devise an intelligent and automated approach to optimize security and prevent the occurrence of vulnerabilities or mitigate the vulnerabilities. The autonomic computing is a nature-inspired and self-management-based computational model. In this paper, an autonomic-computing-based integrated framework is proposed to detect, fire the trigger of alarm, assess, classify, prioritize, mitigate and manage the software vulnerability automatically. The proposed framework uses a knowledge base and inference engine, which automatically takes the remediating actions on future occurrence of software security vulnerabilities through self-configuration, self-healing, self-prevention and self-optimization as per the needs. The proposed framework is beneficial to industry and society in various aspects because it is an integrated, cross-concern and intelligent framework and provides more secured self-managed environment to the organizations. The proposed framework reduces the security risks and threats, and also monetary and reputational loss. It can be embedded easily in existing software and incorporated or implemented as an inbuilt integral component of the new software during software development.     

Effect of wavelength of fish-like undulation of a hydrofoil in a free-stream flow

Fish-like undulating body was proposed as an efficient propulsion system, and various mechanisms of thrust generation in this type of propulsion are found in the literature—separately for undulating and pitching fishes/foil. The present work proposes a unified study for undulating and pitching foil, by varying wavelength \(\lambda \) (from 0.8 to 8.0) of a wave travelling backwards over the NACA0012 hydrofoil in a free-stream flow; the larger wavelength is shown to lead to the transition from the undulating motion to pitching motion. The effect of wavelength of undulation is studied numerically at a Reynolds number \(Re=4000\), maximum amplitude of undulation \(A_{max}=0.1\) and non-dimensional frequency of undulation \(St=0.4\), using level-set immersed-boundary-method based in-house 2D code. The Navier–Stokes equation governing the fluid flow is solved using a fully implicit finite-volume method, while level-set equation governing the movement of the hydrofoil is solved using an explicit finite-difference method. It is presented here that the thrust generation mechanism for the low wavelength case undulating \((\lambda =0.8)\) foil is different from the mechanism for the high wavelength pitching foil. With increasing wavelength, mean thrust coefficient of the undulating foil increases and asymptotes to value for the pure pitching foil. Furthermore, the ratio of maximum thrust coefficient to maximum lateral force coefficient is found to be larger for the smaller wavelength undulating foil as compared with the larger wavelength pitching foil.     

Design and evaluation of acrylate polymeric carriers for fabrication of pH-sensitive microparticles

Colon-targeted microparticles loaded with a model anti-inflammatory drug were fabricated using especially designed acrylic acid–butyl methacrylate copolymers. Microparticles were prepared by oil-in-oil solvent evaporation method using Span 80 as emulsifier. Microparticles were found to be spherical in shape, hemocompatible and anionic with zeta potential of ?27.4 and ?29.0?mV. Entrapment of drug in the microparticles was confirmed by Fourier transform infrared (FTIR) spectroscopy. However, X-ray diffraction (XRD) and differential scanning calorimetry (DSC) revealed amorphous nature of microparticles due to the dilution effect of amorphous polymer. The microparticles released less than 5% drug at pH 1.2, while more than 90% of the drug load was released at pH 7.4. This suggested the colon targeting nature of the formulations. In experimentally developed colitis in Wistar rats, the microparticle formulation showed significant reduction (p?相似文献   

Laser ablated lead free (Na,K) NbO<Subscript>3</Subscript> thin films with excess alkali-content

Lead free (Na_0.5K_0.5) NbO₃ (NKN) being hygroscopic in nature is very difficult to be fabricated with enhanced properties in thin films. To maintain stoichiometry 0, 5 and 10% mole excess of Na on A-site were added on NKN bulk targets. The perovskite ABO₃ crystal structure incorporating 0, 5 and 10% excess alkali ions were grown on Pt/Ti/SiO2/Si substrate by pulsed laser deposition, using stoichiometric high density ceramic targets. X-ray diffraction peaks and Raman scattering spectra suggest the formation of single phase of the film in monoclinic phase. The dielectric properties and leakage current is improved with increasing amount of Na concentration. The reduction in leakage current with addition of excess Na concentration may be due to increase in grain size decrease in the connection of grain boundaries with grains. The impedance spectra of the film shows single dielectric relaxation which is non-debye type and the relaxation frequency is shifted to higher side at higher frequency.     

Growth and properties of Cu<Subscript>2</Subscript>ZnSnS<Subscript>4</Subscript> thin films prepared by multiple metallic layer stacks as a function of sulfurization time

In this paper, we report the two stage growth of Cu₂ZnSnS₄ (CZTS) thin films as a function of sulfurization time. First, magnetron sputtered metallic precursors were deposited sequentially (Zn/Cu/Sn/Cu) over rotating glass substrates held at 230?°C. Later, the sputtered precursors were heat treated at 500?°C in the ambiance of sulfur for various time durations in the range, 10–120 min. The sulfur treated samples were examined using various analytical tools to understand the role of sulfurization time on the CZTS growth and properties. From composition and structural analysis, Zn/Cu/Sn/Cu precursors sulfurized for shorter duration (10 and 20 min) revealed severe deficiency of sulfur that resulted in several metallic, bi-metallic and metal sulfide phases. With the increase of sulfurization time to 30 min, sulfur incorporation was enhanced and reached stoichiometric ratio (~50% S) for CZTS growth, however, samples were poorly crystalline in nature and consisted of prominent Cu_2?xS phase as well. The Zn/Cu/Sn/Cu precursors sulfurized for 60 min exhibited prominent CZTS phase without Cu_2?xS phase. Further, rise in sulfurization time to 120 min enabled drastic improvement in crystallinity of CZTS phase. Raman mapping over 60 µm × 60 µm for these films confirmed the homogeneous phase growth of CZTS. XPS study revealed the oxidation states of Cu¹⁺, Zn²⁺, Sn⁴⁺ and S^2? in CZTS films. The optimized films showed high absorption coefficient of 10⁵ cm^?1 with an optical band gap of 1.51 eV. These films showed leaf like grain morphology with high mobility and low resistivity of 18.2 cm²/V-s and 0.7 Ω-cm, respectively.