Single disperser design for coded aperture snapshot spectral imaging

We present a single disperser spectral imager that exploits recent theoretical work in the area of compressed sensing to achieve snapshot spectral imaging. An experimental prototype is used to capture the spatiospectral information of a scene that consists of two balls illuminated by different light sources. An iterative algorithm is used to reconstruct the data cube. The average spectral resolution is 3.6 nm per spectral channel. The accuracy of the instrument is demonstrated by comparison of the spectra acquired with the proposed system with the spectra acquired by a nonimaging reference spectrometer.     

Wrinkled 2D Materials: A Versatile Platform for Low‐Threshold Stretchable Random Lasers

A stretchable, flexible, and bendable random laser system capable of lasing in a wide range of spectrum will have many potential applications in next‐ generation technologies, such as visible‐spectrum communication, superbright solid‐state lighting, biomedical studies, fluorescence, etc. However, producing an appropriate cavity for such a wide spectral range remains a challenge owing to the rigidity of the resonator for the generation of coherent loops. 2D materials with wrinkled structures exhibit superior advantages of high stretchability and a suitable matrix for photon trapping in between the hill and valley geometries compared to their flat counterparts. Here, the intriguing functionalities of wrinkled reduced graphene oxide, single‐layer graphene, and few‐layer hexagonal boron nitride, respectively, are utilized to design highly stretchable and wearable random laser devices with ultralow threshold. Using methyl‐ammonium lead bromide perovskite nanocrystals (PNC) to illustrate the working principle, the lasing threshold is found to be ≈10 µJ cm^?2, about two times less than the lowest value ever reported. In addition to PNC, it is demonstrated that the output lasing wavelength can be tuned using different active materials such as semiconductor quantum dots. Thus, this study is very useful for the future development of high‐performance wearable optoelectronic devices.     

Irradiation induced effects on Ni3N/Si bilayer system

The irradiation effect in Ni₃N/Si bilayers induced by 100 MeV Au ions at fluence 1.5 × 10¹⁴ ions/cm² was investigated at room temperature. Grazing incidence X-ray diffraction determined the formation of Ni₂Si and Si₃N₄ phases at the interface. The roughness of the thin film was measured by atomic force microscopy. X-ray reflectivity was used to measure the thickness of thin films. X-ray photoelectron spectroscopy has provided the elemental binding energy of Ni₃N thin films. It was observed that after irradiation (Ni 2p_3/2) peak shifted towards a lower binding energy. Optical properties of nickel nitride films, which were deposited onto Si (100) by ion beam sputtering at vacuum 1.2 × 10⁻⁴ torr, were examined using Au ions. In-situ I–V measurements on Ni₃N/Si samples were also undertaken at room temperature which showed that there is an increase in current after irradiation.     

Magnesium oxychloride cement concrete

The scope of magnesium oxychloride (MOC) cement in concrete works has been evaluated. MOC cement concrete compositions of varying strengths having good placing and finishing characteristics were prepared and investigated for their compressive and flexural strengths, E-values, abrasion resistance etc. The durability of MOC concrete compositions against extreme environmental conditions viz. heating-cooling, freezing-thawing, wetting-drying and penetration and deposition of salts etc were investigated. The results reveal that MOC concrete has high compressive strength associated with high flexural strength and the ratio of compressive to flexural strength varies between 6 and 8. The elastic moduli of the compositions studied are found to be 23–85 GPa and the abrasion losses between 0·11 and 0·20%. While alternate heating-cooling cycles have no adverse effect on MOC concrete, it can be made durable against freezing-thawing and the excessive exposure to water and salt attack by replacing 10% magnesium chloride solution by magnesium sulphate solution of the same concentration.     

Vermitechnology for sewage sludge recycling

The present paper is aimed at safe reuse and recycling of sewage sludge (SS) and production of good quality compost using vermicomposting. Three different earthworm species Eiseniafetida (E. fetida), Eudrilus eugeniae (E. eugeniae), Perionyx excavatus (P. excavatus) in individual and combinations were utilized to compare the suitability of worm species for composting of sewage sludge as well as the quality of the end product. The sewage sludge without blending can be directly converted into good quality fertilizer (vermicompost). Vermicomposting resulted in reduction in C/N ratio 25.6 to 6-9, TOC (25%) but increase in electrical conductivity (EC) (47-51%), total nitrogen (TN) (2.4-2.8 times), potassium (45-71%), calcium (49-62%), sodium (62-82%) and total phosphorous (TP) (1.5-1.8 times), which indicated that sewage sludge can be recycled as a good quality fertilizer. The present study also inferred that the application of sewage sludge in the agricultural fields after vermicomposting would not have any adverse effect as the heavy metals (Cu, Mn, Pb and Zn) are now within the permissible limits.     

Occurrence and distribution of ppo activity in floral organs of some standard and local cultivars of tea

Variation of the polyphenol oxidase (PPO) activity in tea flower organs was studied among established cultivars and plants grown locally. Intervarietal differences among the soluble and bound components of the enzyme in floral organs were observed. Quantitative traits were found to be highly conserved among plants of the same clones but differed widely among plants of different clones and of local varieties/cultivars. The latter originated from seeds and some heterogenity was to be expected.     

Investigation of hydrogen isotope effect on storage properties of Zr–Co–Ni alloys

The deuterium desorption pressure-composition isotherms (PCIs) of ZrCo_1−xNi_x-D₂ (x = 0, 0.1, 0.2 and 0.3) systems were generated in this study in the temperature range of 524–603 K using Sievert's type volumetric apparatus. Thermodynamic parameters like enthalpy and entropy change for deuterium desorption reactions involved in the ZrCo_1−xNi_x-D₂ systems were derived using the equilibrium pressure data of PCIs. In order to interpret the hydrogen isotope effect on the storage behaviour of ZrCo_1−xNi_x alloys, the results obtained in the present study were compared with the earlier reported data on the ZrCo_1−xNi_x-H₂ (x = 0, 0.1, 0.2 and 0.3) systems. This comparison revealed that these alloys show normal hydrogen isotope effect where the equilibrium pressure of D₂ is higher than that of H₂ at all experimental temperatures. Based on these observation, it is expected that at the ITER SDS operating conditions the equilibrium pressure of tritium, deuterium and hydrogen will follow the order: p(T₂) > p(D₂) > p(H₂) for these alloys.     

Quantitative profiling of bacteriocins present in dairy-free probiotic preparations of Lactobacillus acidophilus by nanoliquid chromatography-tandem mass spectrometry

Bacteriocins are a heterogeneous group of ribosomally synthesized peptides or proteins with antimicrobial activity, produced predominantly by lactic acid bacteria, with potential applications as biopreservatives and probiotics. We describe here a novel strategy based on a bottom-up, shotgun proteomic approach using nanoliquid chromatography-tandem mass spectrometry (nanoLC-MS/MS) with multiple fragmentation techniques for the quantitative profiling of bacteriocins present in the probiotic preparations of Lactobacillus acidophilus. A direct LC-MS/MS analysis with alternate collision-induced dissociation, high-energy collision dissociation, and electron-transfer dissociation fragmentation following a filter-assisted size-exclusion sample prefractionation has resulted in the identification of peptides belonging to 37 bacteriocins or related proteins. Peptides from lactacin F, helveticin J, lysin, avicin A, acidocin M, curvaticin FS47, and carocin D were predominant. The process of freeze drying under vacuum was observed to affect both the diversity and abundance of bacteriocins. Data acquisition using alternating complementary peptide fragmentation modes, especially electron-transfer dissociation, has significantly enhanced the peptide sequence coverage and number of bacteriocin peptides identified. Multi-enzyme proteolytic digestion was observed to increase the sample complexity and dynamic range, lowering the chances of detection of low-abundant bacteriocin peptides by LC-MS/MS. An analytical platform integrating size exclusion prefractionation, nanoLC-MS/MS analysis with multiple fragmentation techniques, and data-dependent decision tree-driven bioinformatic data analysis is novel in bacteriocin research and suitable for the comprehensive bioanalysis of diverse, low-abundant bacteriocins in complex samples.     

Finishing stages of PET synthesis: A comprehensive model

A comprehensive mathematical model for the finishing stages of polyethylene terephthalate (PET) synthesis is developed. The model takes into account the variables which have significant influences on polymerization but have not been hitherto taken into account, e.g., changing interfacial concentration and the presence of side reactions. The model is applicable to industrial polymerizations, and the predictions agree well with the literature and with certain pilot-plant and commercial data.