Mechanical Property, Thermal Stability and BioDegradability Studies on PLA based Bio-Nanocomposites derived from Agricultural Residues

Looking at the environmental hazards being posed by indiscriminate use of synthetic plastics, abundant research is being done to explore various bio-degradable polymers. In the present study, Cellulose Nano Fibers (CNFs) were extracted from Pineapple Crown using mechano chemical treatment, PLA was synthesized by Simultaneous Saccharification and Fermentation using cellulase enzyme on Acacia Arabica as substrate. Further, ZnO nanoparticles were synthesized by using different precursors. The biocomposite sheets of PLA, PLA+ 5%-20% CNFs, PLA+5% ZnO+5-20 % CNFs and PLA+10% ZnO+5-20 % CNFs were solvent casted. Microbial efficacy test was done using E.coli and with inclusion of ZnO nanoparticles the microbial resistance has increased. Noteworthy vibration band of the sheets were observed in the wavelength range of 3700 to 2800 cm-1 from the FTIR analysis, which shows that there is only a physical interaction rather than chemical. The crystallinity increased for initial concentration, but was similar to the neat PLA. Significant increase in tensile strength and maximum elongation at break was observed in PLA + 5% ZnO + 10% CNFs sheet. Sheets were allowed to degrade naturally and significant weight loss was observed after 120 days with maximum reduction of 38.4 %. Morphological analysis through SEM revealed the uniform distribution of fillers in the polymer matrix. TGA studies have shown that the degradation temperatures were in the range of 320-405oC. The thermal stability decreased with the increase in ZnO concentration. The results have shown a promising and sustainable use in various applications in view of microbial resistance and bio-degradability.

Thermally driven structural phase transformation and dislocation density of CdS nanoparticles precipitated without surfactant in KOH alkaline medium

The present research demonstrates a detailed discussion for the effect of annealing temperature on the structural transformation and surface morphology of the CdS nanoparticles synthesized using the precipitation method without surfactant in KOH alkaline medium. The annealing temperature used was in the range of 160 – 480 oC. The samples structural, functional group and morphological properties were investigated by using XRD, FTIR and SEM techniques. XRD analysis reveals that the CdS has gradually been transformed from the pure cubic to hexagonal polycrystalline structure as well as improved crystallinity upon increasing the temperature. Besides, the parameters of average crystallite size and dislocation density were calculated using the established Debye- Scherrer equation. The average crystallite size was in nano-dimension and increases gradually with temperature. The FTIR spectra indicate that the characteristic vibration band of CdS emerged in the lower wavenumber region of 650 and 500 cm-1, and the band becomes stronger as the temperature rises. Also, the SEM images demonstrate that the CdS exhibits uniform spherical morphology and the particle size grows larger at elevated temperatures. The improved crystallinity and structural properties tuning ability against temperature allows beneficial optical applications as solar cells, photocatalysts, non-linear optics, light emitting diodes and optoelectronic devices.

Vibration Band Gap Characteristics of Two-Dimensional Periodic Double-Wall Grillages

In this article, the wave finite element method (WFEM) is used to calculate the band gap characteristics of two-dimensional (2D) periodic double-wall grillages (DwGs), which are verified by the grillage model vibration measurement experiment and finite element calculation. To obtain the band gap characteristics of periodic DwGs, the finite element calculation model is established according to the lattice and energy band theory and the characteristic equation of the periodic unit cell under the given wave vector condition is solved based on Bloch theorem. Then, the frequency transfer functions of finite-length manufactured and finite element models are obtained to verify the band gap characteristics of periodic DwGs. Finally, the effects of material parameters and structural forms on band gap characteristics and transfer functions are analyzed, which can provide a reference for engineering structure vibration and noise reduction design.

Utilization of Corn Oil through Water Degumming Process for Lecithin Emulsifier Production

Lecithin is an emulsifier that plays an active role in reducing surface tension in making emulsions. The production of lecithin from other vegetable oils allows the use of other types of vegetable oil as a source of lecithin production to replace soy-based oil, which has begun to be used as a bioenergy raw material. This study aims to find an alternative source of new lecithin derived from corn oil by knowing the characteristics of lecithin and applied to mayonnaise. The resulting lecithin was used in mayonnaise with a 2 factorial randomized block design method consisting of 3 levels. Based on the results obtained, the characteristic of corn oil lecithin is that the largest content is hexadecanoic acid which is 44.79%, and the strongest vibration band is CH2 vibration with stretching modes of symmetry and asymmetry at 2922 and 2853 cm–1 and the terminal CH3 group in the 1374 cm–1. L3C3 treatment was the best result with 60% fat content, 4% emulsion stability, 2.12 cP viscosity, and 1.42 × 10–3 N/m surface tension and organoleptic showed a preference value, namely color 4.4 (like), taste 3.2 (sufficient like), smell 4 (like), and texture 3.80 (like it).

Quantitative and Sensitive Mid-Infrared Frequency Modulation Detection of HCN behind Shock Waves

Despite its key role for the study and modeling of nitrogen chemistry and NOx formation in combustion processes, HCN has only rarely been detected under high-temperature conditions. Here, we demonstrate quantitative detection of HCN behind incident and reflected shock waves using a novel sensitive single-tone mid-infrared frequency modulation (mid-IR-FM) detection scheme. The temperature-dependent pressure broadening of the P(26) line in the fundamental CH stretch vibration band was investigated in the temperature range 670K≤T≤1460K, yielding a pressure broadening coefficient for argon of 2γAr296K=(0.093±0.007)cm−1atm−1 and a temperature exponent of nAr=0.67±0.07. The sensitivity of the detection scheme was characterized by means of an Allan analysis, showing that HCN detection on the ppm mixing ratio level is possible at typical shock wave conditions. In order to demonstrate the capability of mid-IR-FM spectroscopy for future high-temperature reaction kinetic studies, we also report the first successful measurement of a reactive HCN decay profile induced by its reaction with oxygen atoms.

Synthesis and characterization of (3-aminopropyl) triethoxysilane (APTES) functionalized zeolite AlPO-18

Over the years, functionalization of zeolite is gaining popularity among researchers to further modify the properties of the zeolite for wide applications. The procedure of functionalization is crucial to ensure that the framework and structure of the zeolite would not be destroyed by the functionalization process. In this work, zeolite AlPO-18 was synthesized via hydrothermal synthesis method and functionalized by (3-Aminopropyl) triethoxysilane (APTES). The effect of the APTES functionalization on zeolite AlPO-18 was investigated in this work. Both unfunctionalized and silane-functionalized zeolite AlPO-18 were characterized using Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and Thermogravimetric analysis (TGA) for their properties. The morphology and the composition of the elements present in zeolite AlPO-18 and zeolite NH2-AlPO-18 were examined using Field Emission Scanning Electron Microscopy (FESEM) and Energy-Dispersive spectroscopy (EDX) respectively. The XRD pattern of NH2-AlPO-18 was similar to that of zeolite AlPO-18, however, the intensity of the peaks was lower compared to zeolite AlPO-18. Based on the FTIR spectra, the presence of N-H stretching and bending vibration band of aminosilane were observed in the NH2-AlPO-18 sample. According to FESEM images, the morphology of NH2-AlPO-18 was comparable to that of zeolite AlPO-18 even after functionalization, proving that functionalization of aminosilane on zeolite does not affect on the zeolite structure. Besides that, EDX proves the presence of 3.02 % of element N in the NH2-AlPO-18 sample which is absent in the zeolite AlPO-18 sample. All of the characterizations evinced the presence of aminosilane, APTES in the NH2-AlPO-18 sample.

Ozone Activation on TiO2 Studied by IR Spectroscopy and Quantum Chemistry

The adsorption of different isotopic ozone mixtures on TiO2 at 77K was studied using FTIR spectroscopy and DFT calculations of cluster models. In addition to weakly bound ozone with band positions close to those of free or dissolved molecules, the spectrum of chemisorbed species was observed. The splitting of the ν1+3 combination band to eight maxima due to different isotopomers testified to the loss of molecule symmetry. The frequencies of all the isotopic modifications of the ozone molecules which form monodentate or bidentate complexes with four- or five-coordinated titanium atoms were calculated and compared with those of experimentally observed spectra. The four considered complexes adequately reproduced the splitting of the ν1+3 vibration band and the lowered anharmonism of chemisorbed O3. The energetically most favorable monodentate complex with four-coordinated titanium atoms showed good agreement with the observed spectra, although a large difference between the frequencies of ν1 and ν3 modes was found. For better coherence with the experiment, the interaction of the molecule with adjacent cations must be considered.

Potential Recognition Layer in Electrochemical Sensor: A Comparative Characterization of p-Cyano Schiff Base Compounds

The effective conjugation of electrons in aromatic Schiff bases has been utilized as an electrochemical sensor in forensic, pharmaceutical and environmental applications. The use of the Schiff base enhances the sensitivity and selectivity of the sensor. In this study, p-cyano Schiff base derived from 4-(4-aminostyryl)benzonitrile and three different aldehydes were synthesized. The spectroscopic techniques via Fourier transform-infrared spectroscopy (FT-IR), Uv-Vis spectrophotometry and Nuclear Magnetic Resonance (NMR) of 1H and 13C were used for structural elucidation resulted compounds. The targeted p-cyano Schiff base showed a clear imine (C=N) stretching vibration band at 1681-1708 cm-1, n→π* electronic transition at 355-360 nm in UV-Vis and a singlet: 8.34-8.39 ppm and 118.07-119.09 ppm for 1H and 13C NMR, respectively, supporting the formation of Schiff bases. The application of Schiff base as spacer in electrochemical DNA (E-DNA) sensor has not been much research done on it so far. The obtained compounds are potentially valuable for electrochemical-DNA sensor study in the future.