The World Health Organization (WHO) declared the coronavirus disease of 2019 (COVID-19) as a pandemic due to its widespread global infection. This has resulted in lockdown under different phases in many nations, including India, around the globe. In the present study, we report the impact of aerosols on surface ozone in the context of pre-lockdown (01 st - 24th March 2020 (PLD)), lockdown phase1 (25th March to 14th April 2020 (LDP1)), and lockdown phase 2 (15th April to 03 rd May 2020 (LDP2)) on clear days at a semi-arid site, Anantapur in southern India using both in situ observations and model simulations. Collocated measurements of surface ozone (O 3 ), aerosol optical depth (AOD), black carbon mass concentration (BC), total columnar ozone (TCO), solar radiation (SR), and ultraviolet radiation (UV-A) data were collected using an Ozone analyzer, MICROTOPS sunphotometer, Ozonometer, Aethalometer, and net radiometer during the study period. The diurnal variations of O 3 and BC exhibited an opposite trend during three phases. The concentrations of ozone were ∼10.7% higher during LDP1 (44.8 ± 5.2 ppbv) than the PLD (40.5 ± 6.0 ppbv), which mainly due to an unprecedented reduction in NOx emissions leading to a lower O 3 titration by NO. The prominent increase in the surface zone during LDP1 is reasonably consistent with the observed photolysis frequencies (j (O 1 D)) through Tropospheric Ultraviolet and Visible (TUV) model. The results show that a pronounced spectral and temporal variability in the AOD during three lockdown phases is mainly due to distinct aerosol sources. The increase in AOD during LDP2 due to long-range transport can bring large amounts of mineral dust and smoke aerosols from the west Asian region and central India, and which is reasonably consistent with the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) air mass back trajectories and Moderate Resolution Imaging Spectroradiometer (MODIS) fire counts analysis over the measurement location. Overall, a drastic reduction in BC concentration (∼8.4%) and AOD (10.8%) were observed in the semi-arid area during LDP1 with correspondence to PLD. The columnar aerosol size distributions retrieved from the spectral AODs followed power-law plus unimodal during three phases. The absorption angstrom exponent (AAE) analysis reveals a predominant contribution to the BC from biomass burning activities during the lockdown period over the measurement location.

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The book chapter mainly deals with the microwave sintering of high quality crystals of La MMnO M = Ni or Co ceramics. Double perovskite La MMnO M = Ni or Co ceramics with average particle size of ~ nm were manufactured using microwave sintering at °C for min in N atmosphere for the first time. The morphology, structure, composition, and magnetic properties of the prepared compacts were characterized using X-ray diffraction XRD , scanning electron microscopy SEM , transmission electron microscopy TEM , energy-dispersive X-ray spectroscopy EDX , infrared spectroscopy IR and FTIR , and physical properties measurement system PPMS . The corresponding dielectric property was tested in the frequency range of kHz MHz and in the temperature range of K, and the ceramics exhibited a relaxation-like dielectric behavior.Keywords: ceramics, microwave sintering, microstructures, XPS, multiferroic properties . IntroductionMicrowave sintering MWS is emerging and an innovative sintering technology for processing of ceramic materials and is commonly related with volumetric and uniform heating. MWS is one of the exciting new fields in material science with vast potential for preparation of novel and/or nanostructured ceramics/materials. Microwave heating has some important benefits Microwave sintering has developed in recent years as a promising technology for faster, cheapest and most environmental-friendly processing of a wide variety of materials, which are regarded as significant advantages over conventional sintering procedures. Microwave radiation/heating for sintering of ceramic constituents has recently appeared as a newly motivated scientific approach [ ].Microwave sintering approach has unique advantages over conventional sintering methods in many respects. The essential difference in the conventional and microwave sintering processes is in the heating mechanism Figure . In microwave heating, the materials themselves absorb microwave energy and then transform it into heat within the sample volume and sintering can be completed in shorter times. In microwave sintering, the heat is generated internally within the test sample due to the rapid oscillation of dipoles at microwave frequencies [ ]. The contribution of diffusion from external sources is lesser. The internal and volumetric heating makes the sintering rapidly and uniformly. The heat generated through conventional heating is generally transferred to the sample via radiation, conduction, and convention [ ]. This process takes longer duration for sintering the materials and causes some of the constituents to evaporate. This may lead to modify the desired stoichiometry and grain. Figure .Comparison of heating mechanism in microwave and conventional sintering methods. Advanced Ceramic Processing 2In contrast, microwave energy is transferred directly to the material through molecular interaction with an electromagnetic field. Microwave heating is more effective than conventional methods in terms of the usage of energy, produces higher temperature homogeneity, and...

The climatology of aerosol optical properties is retrieved and analysed for the period from June 2006 to November 2017 over the Arabian Sea from the Cloud‐Aerosol Lidar with Orthogonal Polarization (CALIOP) onboard Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) and Moderate Resolution Imaging Spectroradiometer (MODIS) onboard Aqua satellite. Strong seasonality and latitudinal gradients in the columnar aerosol optical depth, dust aerosol optical depth (DOD) over the Arabian Sea are observed. Most of the aerosols over the North Arabian Sea (NAS) and the Central Arabian Sea are confined to the surface (i.e., 0–3 km). However, the seasonal mean high extinction coefficient is found during summer over the Arabian Sea. The high vertical extent of aerosols (with higher extinction coefficient) at altitudes >4 km emphasizes the continental aerosol effluence from the southwestern peninsular Indian subcontinent during winter, spring and autumn seasons. The contribution of dust extinction coefficient to the total columnar DOD has been observed to be high over NAS (>35%) at 0–1 km altitude bin during all the seasons and it is lowest (<15%) at the altitude range of 5–6 km. Dust fraction (DF) shows a clear latitudinal variation with a peak over NAS and diminishes towards SAS. The highest DF is observed over NAS during spring (82%) even though the dust extinction coefficient attained maximum during summer (0.81 ± 0.07 km−1). This is due to the strong westerly winds over NAS from the coast of Oman during spring. A positive difference between DF derived from MODIS and CALIPSO is noticed, and it might be due to the limitation of MODIS in discriminating the aerosol and the cloud from its passive sensor reliable than an active sensor like lidar in CALIPSO. The outcomes of the present study will serve as a reliable source for future studies of dust‐regional scale climate interactions over the Arabian Sea.