Shelf-Life Extension of Fresh Ready-to-Bake Pizza by the Application of Modified Atmosphere Packaging

Combined effects of modified atmosphere packaging (MAP) and refrigeration (7±1 °C) were studied on shelf-life extension of ready-to-bake pizza. The gas atmospheres in the present study included four variables, namely viz. MAP1, air (control); MAP 2, 100% CO₂; MAP 3, 100% N₂; and MAP 4, 50%CO₂/50%N₂. The effect of MAP variables was observed for moisture content, water activity, pH, titratable acidity, free fatty acids, peroxide value, thiobarbituric acid, tyrosine content, lycopene content and L* a* b* values. The results indicated that MAP with 100% CO₂ significantly inhibited the lipid oxidation, reduced proteolysis and prevented total acidity (less decrease in pH). Also, the MAP (MAP 2) showed preservative effect on colour indices and shelf life higher than other treatments. Sensory analysis showed that the control samples had a limited shelf life of 5 days while a significant increase in shelf life of 15 days (300% increase) was achieved under modified atmospheres for unbaked pizza samples.     

A low‐profile quad‐port UWB MIMO antenna using defected ground structure with dual notch‐band behavior

A compact (45 × 45 × 1.6 mm³) ultrawide‐band (UWB), multiple‐input multiple‐output (MIMO) design using microstrip line feeding is presented. The proposed design comprises four elliptical monopoles placed orthogonally on a cost‐effective FR‐4 substrate. In order to improve the impedance bandwidth and lessen the return loss of the MIMO antenna, defects in ground plane are created by etching symmetrical square slots and half‐rings. Moreover, a different method (of unsymmetrical H‐shaped slot with C‐shaped slot) was proposed into the patch to introduce dual‐band rejection performance from UWB at center frequency 5.5 GHz (covering lower WLAN as well as upper WLAN) and 7.5 GHz (X band). In addition, a stub is introduced at the edge of each defected ground structure to obtain isolation >–22 dB covering entire performing band from 2 to 16.8 GHz (where, S₁₁ < –10 dB). The proposed design has miniaturized size, very low envelop correlation coefficient less than 0.1, stable gain (2‐4 dBi except for notch bands). Furthermore, various MIMO performance parameters are within their specifications, such as diversity gain (= 10 dB), total active reflection coefficient (<–5 dB, and channel capacity loss (<0.35 bits/s/Hz). The presented design is optimized using the HFSS software, and fabricated design is tested using vector network analyzer. The experimental results are in good agreement with the simulation results.     

Hot Corrosion of Stabilized Zirconia Thermal Barrier Coatings and the Role of Mg Inhibitor

The 3–4 mol% yttria‐stabilized zirconia (YSZ) is widely used as a material for thermal barrier coating; however, the corrosive constituents present in fuel typically result in mechanical disintegration of YSZ coatings. The 3–4 mol% YSZ coatings with respective porosity of ~3% and ~22% have been undertaken with the objective to compare the hot corrosion behavior in air and sulfur‐rich atmospheres. The coatings are kept in contact with V₂O₅ + MgO powder mixture at 750°C for different dwell times of 24 and 76 h. The samples kept in air have shown intact YSZ layer for both the coatings, whereas a delamination of YSZ layer is observed for high porosity sample kept in sulfur‐rich atmosphere. XRD patterns of all the samples treated in sulfur‐rich atmosphere have indicated a phase transformation in YSZ from tetragonal to monoclinic. However, no such phase transformation has been found for samples treated in air. The V₂O₅‐induced hot corrosion attack on YSZ coating in air has been successfully inhibited by MgO, which forms a thermally stable Mg₃V₂O₈ compound. However, in sulfur‐rich atmosphere, MgO is partially consumed to form sulfates, which allows certain fraction of V₂O₅ to react with Y₂O₃ causing the degradation of top coat.     

Synthesis and Assessment of Novel Gelatin–Chitosan Lactate Cohydrogels for Controlled Delivery and Tissue Engineering Applications

The current study discusses the synthesis of novel gelatin–chitosan lactate cohydrogels. Mechanical studies indicated the viscoelastic nature of the cohydrogels. The cohydrogels were predominantly elastic in nature. Inherent mechanical stability of the cohydrogels was better than the pristine gelatin hydrogel. Incorporation of chitosan lactate improved the in vitro swelling and the drug release properties of the cohydrogels. The cohydrogels showed good antimicrobial drug delivery capacity. The properties of the developed cohydrogels demonstrated that they could be used as delivery vehicles for antimicrobial drugs. Cell proliferation study suggested that the cohydrogels supported the proliferation of the human keratinocytes.     

Bifurcation Analysis on Pt and Ir for the Reduction of NO by CO

Due to the importance of the NO‐CO reaction in current catalytic converters, reduction of NO by CO on Pt group catalysts is important to study. Various reaction mechanisms have been proposed for the NO‐CO reaction on Pt(100), which shows bifurcations, kinetic oscillations and multiple steady states under ultra high vacuum (UHV) conditions due to complex surface dynamics. Some experiments on supported Pt group catalysts reported in literature show oscillations and bistability under atmospheric conditions as well. Industrially relevant conditions require the modelling and detailed analysis of the system at atmospheric pressure. We have proposed a reaction mechanism for the NO‐CO system on Pt group catalysts and coupled it with an isothermal PSR model to obtain solutions at atmospheric conditions with the continuation software CONTENT 1.5, at different operating conditions. Simulation results suggest that Pt(111) shows bifurcations at certain operating conditions while Ir(111) shows stable solutions at all the operating conditions studied here.     

TiO2 nanoparticles prepared by mechanical reduction technique for superior DMFC nanocomposite PVA membranes

TiO₂ nanoparticles (50–80 nm) are produced by simple nanomilling by stirred media mill. Reasonably high purity TiO₂ nanoparticles are observed by inductively coupled plasma atomic emission spectroscopy. Thus, the prepared TiO₂ nanoparticles are applied as inorganic nanofillers for direct methanol fuel cell nanocomposite proton-exchange membranes. Cross-linked sulphonated polyvinyl alcohol is used for membrane preparation. Water uptake and ion exchange capacity of membranes are observed to be enhanced due to increase in concentration of nanoparticles. Very high proton conductivity and extremely diminutive methanol permeability are achieved. In addition, the durability and lifetime is observed to be exceptionally good (>2000 h).

Abbreviations: DW: Deionised water; DLS: Dynamic light scattering; DMFC: Direct methanol fuel cell; DMSO: Dimethyl sufoxide; DSDSBA: 4-formylbenzene-1,3-disulphonic acid disodium salt hydrate; GA: Glutaraldehyde; FTIR: Fourier transform infrared spectroscopy; ICP-AES: Inductively coupled plasma atomic emission spectroscopy; IEC: Ion exchange capacity; MCO: Methanol crossover; MO₂: Metallic oxides; Na-PAA: Sodium-polyacrylic acid; PEM: Proton exchange membrane; PEMFC: Proton-exchange membrane fuel cells; PSD: Particle size distribution; PVA: Poly vinyl alcohol; RH: Relative humidity; SEM: Scanning electron microscopy; SPEEK: Sulphonated poly (ether ether ketone); SPVA: Sulphonated polyvinyl alcohol; SPVA (5%): composite polymer membrane with 5% TiO₂; SPVA (10%): composite polymer membrane with 10% TiO₂; SPVA (15%): composite polymer membrane with 15% TiO₂; TEM: Transmission electron microscope; TG-DSC: Thermo gravimetric differential scanning     

Synthesis and optimization of soy protein fiber based graft copolymer through response surface methodology for removal of oil spillage

Present study deals with the development of novel biodegradable polymer device for petroleum fraction removal from different petroleum-saline emulsion. Soy protein fiber was graft copolymerized with poly(methylmethacrylate) using sequential experimental design approach. Six process variables, such as solvent amount, monomer concentration, FAS:KPS ratio, reaction time, reaction temperature, and pH were taken at two levels as per Resolution-V design. Significant process variables were monomer concentration, reaction temperature, and pH. In phase-2, screened variables were taken for model building and optimization as per optimal response surface design. At optimum conditions (monomer concentration: 3.10 mmol L^?1; reaction temperature: 84.2 °C; pH 6.03), the graft percentage was found to be 272 %. Graft copolymer was characterized using FTIR, SEM, TGA, DTA, and DTG techniques. Further, graft copolymer was evaluated for acid–base and moisture resistance behavior. The synthesized soy protein fiber based polymer showed 76–70 % petroleum fraction absorption from different petroleum-saline emulsions.     

System Ho-Rh-O: Phase Equilibria, Chemical Potentials and Gibbs Energy of Formation of HoRhO3

The thermodynamic properties of the HoRhO₃ were determined in the temperature range from 900 to 1300?K by using a solid-state electrochemical cell incorporating calcia-stabilized zirconia as the electrolyte. The standard Gibbs free energy of formation of orthorhombic perovskite HoRhO₃, from Ho₂O₃ with C-rare earth structure and Rh₂O₃ with orthorhombic structure, can be expressed by the equation; $$ \Updelta G_{{{\text{f}}({\text{ox}})}}^{ \circ } \left( { \pm 78} \right)/({\text{J}}/{\text{mol}}) = - 50535 + 3.85\left( {T/{\text{K}}} \right) $$ Using the thermodynamic data of HoRhO₃ and auxiliary data for binary oxides from the literature, the phase relations in the Ho-Rh-O system were computed at 1273?K. Thermodynamic data for intermetallic phases in the binary Ho-Rh were estimated from experimental enthalpy of formation for three compositions from the literature and Miedema??s model, consistent with the phase diagram. The oxygen potential-composition diagram and three-dimensional chemical potential diagram at 1273?K, and temperature-composition diagrams at constant oxygen partial pressures were computed for the system Ho-Rh-O. The decomposition temperature of HoRhO₃ is 1717(±2)?K in pure O₂ and 1610(±2)?K in air at a total pressure p ^o?=?0.1?MPa.