材料科学与工程杂志

Nanocomposite polymer blend electrolytes composed of poly(vinyl alcohol) (PVA) as a host polymer, Polyaniline (PANI) as an additive, Lithium Perchlorate (LiClO₄) as dopant salt were prepared for different concentrations of Antimony Trioxide (Sb₂O₃) as inorganic filler with the constant ratio of PVA and PANI polymers by using electrospinning technique and investigated. The complexations of the samples were analyzed using X-ray diffraction (XRD) and FTIR spectroscopic techniques which indicate complexation between the polymers, salt and inorganic filler whereas micro surface structure of the composite electrolytes was analyzed using scanning electron microscope (SEM) studies which reveal the surface morphology of the prepared samples. Thermogravimetric analyses (TGA) shows enhancement in thermal stability of composite polymer electrolytes films upon incorporation of filler. Sample films of PVA-PANI-LiClO₄-Sb₂O₃ were subjected to AC impedance spectroscopic analysis for the measurement of conductivity at different temperature. The effect of temperature and filler concentration on the ionic conductivity values have been studied in the range 298-353K. It was found that the polymer electrolyte with 9 wt% of Sb₂O₃ exhibits the highest ionic conductivity value of 8.394 × 10^-5 S cm^-1 at ambient temperature. The temperature dependence of the conductivity of the composite polymer electrolyte films seems to obey the VTF relation.

The aim of this paper is to review design and analysis of bullet resistance jacket projectile penetration. The main energy absorbing mechanisms during ballistic impact are different criteria considered. Delamination, analytical model formation, Experimental, projectile and penetration will be determine impact energy absorbed and initial kinetic energy of the projectile in to target. The material of Kevlar, Twaron, spectra, non-Newtonian’s fluid and natural fibers are used in making bullet proof jacket. Finally, the total energy absorbed by damaged plate is equal to the initial kinetic energy of projectile, ballistic limit of the plate obtained.

A series of Ni substituted MgCuZn polycrystalline ferrite were prepared by a high energy ball-milling followed by the standard double sintering ceramic technique to investigate the impedance spectroscopic studies, within the frequency and temperature range of 100 Hz to 1 MHz at various temperatures within the range of 30oC-490oC these studies were carried out. XRD and SEM patterns were taken to confirm the formation of single phase cubic structure and the grain size. The complex-plane impedance spectra indicates that the material can be represented by both bulk and the grain boundary phenomena at high and low frequencies respectively as two semi-circular arcs was observed. The results of the real impedance Z′ and imaginary part Z′′ at low frequencies are discussed as being attributed to the interfacial polarization; The results of real impedance Z' and imaginary part Z" at various frequiences are discussed along with the dielectric properties of temperature and frequency.

Strain-Based Fatigue Damage Modeling of Plain Woven Glass/Epoxy fabric Composites is well developed by utilizing Helmholtz Free Energy Model, S-N Model and Strain-Life Model. Due to repeated cyclic loading at a defined number of cycles to the failure, Glass Fiber experienced disturbance in their intermolecular bonding structures and finally development of microcracks, macrocracks, cracks and fatigue fracture at final stage. For, validation of Model, Strain Based constant amplitude of fatigue loading is achieved through Fatigue Testing which was performed by adopting the positive load method for evaluation of any potential crack propagation, fiber fractures, de-laminations, etc. With the application of continuous stressing in the material, evaluation of life cycle capabilities of glass fiber composites are essential for Research Development, Structural Design, Quality assurance, Modeling and finally the preparation of Specifications for the product of said Material. By using an epoxy resin system with glass fiber at a mandrel diameters 140 mm and the winding angle of 15° and 90° were selected in four lay-up i.e. 15°, 90°, 15°, 90° had fabricated according to filament winding process. The Specimen is cut into 20 pieces each of width 50 mm, thickness 3.3 mm was fixed in 809 MTS Axial/Torsional Test Machine with constant frequency 1 HZ and the test result was recorded in the Computer connected to that Machine. From the fatigue test, it is observed that final reading at the time of fracture i.e. in terms of running time, axial force, axial displacement, and axial integral count cycle was recorded as 72801.390625 Sec, 0.121522857666016 KN, 4.7763674519961 mm and 72737.50 Cycles. The maximum number of cycle to failure obtained from the fatigue testing is Nf=72737.50 interfere cycles at 1.00 fatigue damage factor, initial strain at 0.00 cycle at 63.57617 sec time was recorded as 0.0244, final strain at 72735.50 cycle at 72801.40 sec was recorded as 0.0659. Initial, at middle and final stress was recorded as 0.329183 GPA initial, varying to 0.58809 GPA at middle point and 0.002202 GPA to 0.00 at failure state. Minimum and Maximum Strain Measurement corresponding to 0001 Cycle were -0.00045313 and 0.0075, at 30000 Cycle -0.00050313 and 0.00995, at 50000 Cycle -0.00075 and 0.0115, at 70000 Cycle (Final Cycle for fracture) was -0.010234375 and 0.515625 which validates the required Strain-based fatigue model achieved through theoretically.

In the present work, we performed a molecular dynamics (MD) simulation of Na-montmorillonite (Na-Mt) in nonambient environment under the crystalline swelling to evaluate the effect of temperature and inorganic salts addition on the interlayer structure and the swelling behavior of Na-Mt. The activities of inorganic salts (NH4Cl, AlCl3, MgCl2 and FeCl3) on the hydration process of Na-Mt at high temperatures (200, 300, 400, 500, and 600 K) and high pressure (HTHP) of P=6 GPa in an isobaric isothermal ensemble (NPT) were investigated. The results showed that addition of inorganic salts into Na-Mt enhanced mobility of the interlayer species, and shrunk the hydration shell of the interlayer ions with a rise in temperature. The salts inhibited swelling by reducing the mobility of the interlayer species and the basal spacing. The type of cations present between the layers, their hydration energies affected the structure and properties of Na-Mt. Chlorine played an important role in the inhibition process of inorganic salts by exerting strong attractive forces on interlayer H2O molecules. Compared with the other salts, the most stable state of Na-Mt at HTHP is achieved with NH4Cl. These results could help a better understanding of the inhibition effect of inorganic salts on Na-Mt and predict the hydration process of Na-Mt at HTHP for further improvement of its structure.

Highlights

• Cl anion hydration energy change is more evident with salt type than temperature
• Inorganic salt and temperature increase shrink the hydration shell of interlayer ions
• NH4Cl addition provides a good inhibition at high temperature and high pressure
• Increasing temperature and hydration degree promote the cation exchange process