Growth of Interconnected ZnO Nanostructures-Its Photocatalytic and Electrochemical Properties

We report the synthesis of interconnected ZnO nano structures through the addition of polyvinyl pyrrolidone (PVP) in a growth medium consisting of ZnCl2 and NaOH at a temperature of 70 0C with a reaction time of 24 hrs. The formation of interconnected ZnO is evaluated in accordance with the reaction time and reaction temperature used for the synthesis, and samples were characterized by powder X-ray diffraction, Fourier transform infra- red (FTIR) spectroscopy, Brunauer-Emmett-Teller(BET) analysis, Field emission scanning electron microscopy (FESEM), Photoluminescence (PL) and Electrochemical methods. BET studies show the mesoporous nature of ZnO grown with the addition of PVP in the growth medium. Interconnected ZnO nanostructures exhibit efficient visible light driven photo catalytic degradation of methylene blue (MB) attributed to interconnected morphology of ZnO. Electro chemical studies have shown that the interconnected ZnO nanostructures give higher order specific capacitance.

Satellite-Based Precipitation Estimates Validation Using Surface Stations in the Central Region of the State of São Paulo, From 1981 to 2019

With the advance of remote sensing technologies, meteorological satellites have become an alternative in the process of monitoring and measuring meteorological variables, both spatially and temporally. The present study brings some additional elements to the validation of satellite-based precipitation estimates by evaluating the CHIRPS (Climate Hazards Group Infra-Red Precipitation with Station) monthly product for the central region of the state of São Paulo, Brazil, in the period 1981-2019. Initially, the general relationship between satellite estimates and surface rainfall data is assessed using the linear adjustment and error analysis in both temporal and spatial perspectives, followed by a trend analysis using Laplace test. The monthly map analysis showed a better performance of CHIRPS during the dry period (April to August) than for the wet period (October to March). Finally, monthly trends showed, in general, the same pattern of variability in rainfall over 38 years and a prevalence toward the reduction of rainfall. In summary, CHIRPS product seems a reasonable alternative for regions that lack historical rainfall information.

Spectral Fingerprint Investigation in the near Infra-Red to Distinguish Harmful Ethylene Glycol from Isopropanol in a Microchannel

Ethylene glycol (EG) and isopropanol (ISO) are among the major toxic alcohols that pose a risk to human health. However, it is important to distinguish them, since EG is more prone to cause renal failure, and can thus be more dangerous when ingested than ISO. Analysis of alcohols such as isopropanol and ethylene glycol generally can be performed with a complex chromatographic method. Here, we present an optical method based on absorption spectroscopy, performed remotely on EG-ISO mixtures filling a microchannel. Mixtures of ethylene glycol in isopropanol at different volume concentrations were analyzed in a contactless manner in a rectangular-section glass micro-capillary provided with integrated reflectors. Fiber-coupled broadband light in the wavelength range 1.3–1.7 µm crossed the microchannel multiple times before being directed towards an optical spectrum analyzer. The induced zig-zag path increased the fluid–light interaction length and enhanced the effect of optical absorption. A sophisticated theoretical model was developed and the results of our simulations were in very good agreement with the results of the experimental spectral measurements. Moreover, from the acquired data, we retrieved a responsivity parameter, defined as power ratio at two wavelengths, that is linearly related to the EG concentration in the alcoholic mixtures.

Highly spatial-resolved chemical metrology on latent resist images

Patterning photoresist with extreme control over dose and placement is the first crucial step in semiconductor manufacturing. But, how to accurately measure the activation of modern complex resists components at sufficient spatial resolution? No exposed nanometre-scale resist pattern is sufficiently sturdy to unaltered withstand inspection by intense photon or electron beams, not even after processing and development. This paper presents experimental proof that Infra-Red Atomic Force Microscopy (IR-AFM) is sufficiently sensitive and gentle to chemically record the vulnerable-yet-valuable lithographic patterns in a chemically amplified resist after exposure, prior to development. Accordingly, IR-AFM metrology provides the long-sought-for insights in changes in the chemical and spatial distribution per component in a latent resist image, both directly after exposure as well as during processing. With these to-be-gained understandings, a disruptive acceleration of resist design and processing is expected.

Fourier transform infra-red spectroscopy to determine formaldehyde to phenol ratio of phenol formaldehyde resole

A model has been proposed to determine the formaldehyde (F) to phenol (P) ratio [F/P] of resole with the help of Fourier transform infra-red spectroscopy. The study is based on the comparison of IR absorbance of the dominant peaks corresponding to the formaldehyde and phenol contents in the resin. This study can be of much use in adhesive coating industries to employ the F/P ratio as a quality tool as well as for competition resin benchmarking. It can also be utilized for understanding the kinetics of the reactions between phenol and formaldehyde. Detailed qualitative analyses of various resoles with different formulations have been discussed in this paper, which can be of potential help for the standard analysis of the commercial resins. The validation of results confirms that the most fitting model offers an error less than 7%. Interestingly, this model can also be applied with blends of different Phenol formaldehyde resoles.