Chapter Characterization of Atmospheric Mercury in the High-Altitude Background Station and Coastal Urban City in South Asia

This study is performed to evaluate the potential sources and seasonal variation of atmospheric mercury (Hg) emissions from regional sources and other influences in India. To achieve this, using the gold amalgam technique with an automated continuous mercury vapour analyzer (TekranTM 2537B). To assess the total gaseous mercury in high altitude mountain peak station at Kodaikanal & coastal/urban air in Chennai region, the impact of changing weather conditions is also evaluated. To compare the past and recent reports of mercury at different locations in the world. The average total gaseous mercury value in Chennai is 4.68 ng/m3, which is higher as compared to Kodaikanal, where it is 1.53 ng/m3. The association between TGM with meteorological parameters in ambient air such as temperature, relative humidity, rainfall intensity, the direction of wind and velocity of was studied. The TGM concentration in India are compared with other nations, the TGM levels are similar to the east and Southeast Asian countries, and also Europe, Sub-Saharan Africa and North America are the averages and maximum concentration generally smaller. This research will help to establish more effective management approaches to mitigate the impacts of atmospheric mercury on the rural and urban environment

Influence of Roller Ball Tool in Single Point Incremental Forming of Polymers

Polymers defend the metals in making complex geometries because of their strength to weight ratio. Utilizing the conventional process has become a challenge in manufacturing customized products. Increase in demand of tailored products in minimum quantities with preferred quality creates the need for developing new techniques. Incremental forming process is an emerging flexible technology that can obtain pre-defined profiles through deformation of metals and polymers in desired thickness at a reasonable cost. In this work, single point incremental forming (SPIF) of different polymer materials is done using roller ball tool and modest fixture system. Materials such as polyvinyl chloride (PVC), polypropylene (PP), polycarbonate (PC), high density poly ethylene (HDPE) are considered for this investigation due to high applications in automobile and biomedical area. The experiments are designed to analyse the influence of variable process parameters such as tool diameter, step size, spindle speed and sheet thickness. The analysis is carried out by characterizing the formability with depth of failure, thickness distribution, surface roughness and microstructure evaluation. Based on the result, the spindle speed and sheet thickness show high response in formability, surface roughness and depth of failure. The tool diameter has a significant effect on the surface roughness. PVC shows the springback resistance and cracks are observed in the circumferential route on the transition area among the bottom and side wall portion

New molecular precursors for metal sulfides

Metal sulfide thin films are important class of materials which have applications in photovoltaics, microelectronics and displays. Chemical vapour deposition (CVD) is well known method for the deposition of high quality thin films. Very few classes of single source precursors (eg: dithiocarbamates, xanthates) were successful for the deposition of good quality metal sulfide films by MOCVD. This limited choice was due to the difficulties of finding precursors with suitable physico-chemical properties. Hence, it is important to develop precursors with suitable volatility, solubility and being able to deposit films with little or no contamination. This work describes the synthesis of a series of metal (Fe, Co, Ni, Zn, Cd) complexes of thio- and dithio-biuret ligands, their structural and spectroscopic characterization and thermal decomposition. The complexes were used as single source precursors for the deposition of iron, cobalt, nickel, zinc, cadmium and zinc cadmium sulfide thin films by AACVD. The effect of alkyl groups, coordinating atoms, deposition temperatures on phases and morphology of the films were studied. The deposited films were characterised by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and atomic force microscopy (AFM). The complex [Fe(SON(CNiPr2)2)3] gave hexagonal troilite FeS films with small amount of tetragonal pyrrhotites Fe1-xS at 300 °C, whereas only troilite FeS was deposited at 350, 400 or 450 °C. Complexes [Fe2(µ-OMe)2 (SON(CNEt2)2)2] and [Fe(SON(CNEt2)2)3] deposited a mixture of hexagonal troilite FeS and cubic pyrite FeS2 films at all temperatures. [Fe(SON(CNMe2)2)3] deposited very thin films of FeS at all temperatures as troilite. Complexes [Co(N(SCNMe2)2)3] and [Co(N(SCNEt2)2)3] deposited hexagonal Co1-xS films at all temperatures of 350-500 °C, whereas [Co(SON(CNiPr2)2)2] gave mixture of cubic and hexagonal Co4S3 films at 280-400 °C. Thiobiuret complex [Ni(SON(CNMe2)2)2] gave orthorhombic Ni7S6. Complexes [Ni(SON(CNMe2CNEt2))2] and [Ni(SON(CNEt2)2)2] gave mixtures of hexagonal Ni17S18 and orthorhombic Ni7S6. In contrast, [Ni(SON(CNiPr2)2)2] gave orthorhombic Ni9S8. Dithiobiuret complexes [Ni(N(SCNMe2SCNEt2))2] and [Ni(N(SCNEt2)2)2] gave hexagonal NiS1.03 at 360 and 400 °C, orthorhombic Ni7S6 phase at 440 and 480 °C. The zinc complexes [Zn(N(SCNMe2)2)2] and [Zn(SON(CNiPr2)2)2] deposited cubic ZnS at 300 and 350 °C, whereas at 400 and 450 °C hexagonal ZnS were apparent [Zn(N(SCNEt2)2)2] gave hexagonal ZnS films at all deposition temperatures. Cadmium complexes [Cd(N(SCNMe2)2)2], [Cd(N(SCNEt2)2)2] and [Cd(SON(CNiPr2)2)2] gave hexagonal CdS films at all deposition temperatures.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Transition metal chalcogenides for next-generation energy storage.

Transition-metal chalcogenide nanostructures provide a unique material platform to engineer next-generation energy storage devices such as lithium-ion, sodium-ion, and potassium-ion batteries and flexible supercapacitors. The transition-metal chalcogenide nanocrystals and thin films have enhanced electroactive sites for redox reactions and hierarchical flexibility of structure and electronic properties in the multinary compositions. They also consist of more earth-abundant elements. These properties make them attractive and more viable new electrode materials for energy storage devices compared to the traditional materials. This review highlights the recent advances in chalcogenide-based electrodes for batteries and flexible supercapacitors. The viability and structure-property relation of these materials are explored. The use of various chalcogenide nanocrystals supported on carbonaceous substrates, two-dimensional transition metal chalcogenides, and novel MXene-based chalcogenide heterostructures as electrode materials to improve the electrochemical performance of lithium-ion batteries is discussed. The sodium-ion and potassium-ion batteries offer a more viable alternative to lithium-ion technology as they consist of readily available source materials. Application of various transition metal chalcogenides such as MoS2, MoSe2, VS2, and SnSx, composite materials, and heterojunction bimetallic nanosheets composed of multi-metals as electrodes to enhance the long-term cycling stability, rate capability, and structural strength to counteract the large volume expansion during the ion intercalation/deintercalation processes is highlighted. The promising performances of layered chalcogenides and various chalcogenide nanowire compositions as electrodes for flexible supercapacitors are also discussed in detail. The review also details the progress made in new chalcogenide nanostructures and layered mesostructures for energy storage applications

Characterization of Atmospheric Mercury in the High-Altitude Background Station and Coastal Urban City in South Asia

This study is performed to evaluate the potential sources and seasonal variation of atmospheric mercury (Hg) emissions from regional sources and other influences in India. To achieve this, using the gold amalgam technique with an automated continuous mercury vapour analyzer (TekranTM 2537B). To assess the total gaseous mercury in high altitude mountain peak station at Kodaikanal & coastal/urban air in Chennai region, the impact of changing weather conditions is also evaluated. To compare the past and recent reports of mercury at different locations in the world. The average total gaseous mercury value in Chennai is 4.68 ng/m3, which is higher as compared to Kodaikanal, where it is 1.53 ng/m3. The association between TGM with meteorological parameters in ambient air such as temperature, relative humidity, rainfall intensity, the direction of wind and velocity of was studied. The TGM concentration in India are compared with other nations, the TGM levels are similar to the east and Southeast Asian countries, and also Europe, Sub-Saharan Africa and North America are the averages and maximum concentration generally smaller. This research will help to establish more effective management approaches to mitigate the impacts of atmospheric mercury on the rural and urban environment

Monoclonal gammopathy of increasing significance: time to screen?

Monoclonal gammopathy (MG) is a frequently detected clonal B-cell or plasma-cell disorder. Importantly, every multiple myeloma (MM) case is preceded by MG. Although clinical algorithms now allow earlier treatment of patients with biomarkers of malignancy before MM-induced tissue damage (CRAB) occurs, most patients are still diagnosed late. It is important to revisit how MG should be managed in clinical practice and whether screening is required. As the prevalence of MG and other medical co-morbidities both rise with increasing age, the degree of contribution of MG to disease states other than malignant progression is often unclear. This can lead to monitoring lapses and under recognition of the organ dysfunction that can occur with monoclonal gammopathy of clinical significance (MGCS). Therefore, models of progression to MM and/or MGCS require further refinement. While MG is currently detected incidentally, a case for screening has been made with ongoing studies in this area. Screening has the potential benefit of earlier detection and prevention of both MGCS and delayed MM presentations, but important drawbacks include the psychosocial impact on individuals and resource burden on healthcare services. MG terminology should transition alongside our increasing understanding of the condition and genomic characterization that have already begun to revise the MG nomenclature. The biology of MG has been poorly understood and is often inferred from the biology of MM, which is unhelpful. We review the literature and case for MG screening in this paper. In particular, we highlight areas that require focus to establish screening for MG

Flexible Supercapacitors: A Materials Perspective

Flexible supercapacitors are highly attractive for the large number of emerging portable lightweight consumer devices. The novelty of a flexible supercapacitor is the incorporation of flexible electrode or substrate material to combine structural flexibility with the inherently high power density of supercapacitors. Flexible supercapacitors can use non-Faradaic energy storage process as seen in the electric double layer capacitor type or a Faradaic mechanism as seen in the pseudocapacitors (PCs). In this review, we account the current progress in pseudocapacitive electrode materials, fabrication techniques and new materials for electric double layer capacitor, and different flexible substrates. Future directions in developing new materials toward improved energy density and cost-effectiveness of the flexible supercapacitors and their usage in combination with lithium-ion batteries are highlighted

Flexible and High Performance Supercapacitors Based on NiCo(2)O(4)for Wide Temperature Range Applications

Binder free nanostructured NiCo2O4 were grown using a facile hydrothermal technique. X-ray diffraction patterns confirmed the phase purity of NiCo2O4. The surface morphology and microstructure of the NiCo2O4 analyzed by scanning electron microscopy (SEM) showed flower-like morphology composed of needle-like structures. The potential application of binder free NiCo2O4 as an electrode for supercapacitor devices was investigated using electrochemical methods. The cyclic voltammograms of NiCo2O4 electrode using alkaline aqueous electrolytes showed the presence of redox peaks suggesting pseudocapacitance behavior. Quasi-solid state supercapacitor device fabricated by sandwiching two NiCo2O4 electrodes and separating them by ion transporting layer. The performance of the device was tested using cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. The device showed excellent flexibility and cyclic stability. The temperature dependent charge storage capacity was measured for their variable temperature applications. Specific capacitance of the device was enhanced by similar to 150% on raising the temperature from 20 to 60 degrees C. Hence, the results suggest that NiCo2O4 grown under these conditions could be a suitable material for high performance supercapacitor devices that can be operated at variable temperatures