Satellite- and ground-based measurements of CO2 over the Indian region: its seasonal dependencies,spatial variability,and model estimates

ABSTRACT

The present study demonstrates the distribution of carbon dioxide (CO₂) concentration over the Indian region and the surrounding oceanic regions during 2009–2012, using measurements from satellites viz., Greenhouse Gases Observing Satellite (GOSAT) and Atmospheric Infrared Sounder, Carbon Tracker (CT) model simulations and flask measurements from two Indian stations Sinhagad (SNG) (73°45′ E, 18°21′36″ N) and Cape Rama (CRI) (73°54′ E, 15°6′ N). The concentration of CO₂ is observed to be maximum during pre-monsoon and shows a decreasing phase during the post-monsoon season. In a regional scale, it is found that Indo-Gangetic Plain and northern India have relatively higher concentrations compared to the other regions. The probability distribution of the concentration differences shows that for most of the time, the differences lie between ±3 ppmv between GOSAT and CT. The comparison between the CO₂ flask measurements over SNG and CRI with respect to that of GOSAT and CT clearly reveals that the differences in CO₂ are as high as 10 ppmv between the ground- and satellite-based measurements. Further, we utilized the Lagrangian model FLEXible PARTicle (FLEXPART) to understand the source?receptor relationship over CRI, SNG, and over the equatorial Indian Ocean (IO). The source contributions from the northern and eastern continental regions of the Indian region are found to be more influential over SNG compared to CRI. It is also found from simulations that the equatorial IO has less influence from the continental source and therefore has a reduced seasonal variability compared to the other regions considered in the present study.     

Cytoprotective effects of geraniin against peroxynitrite- and peroxyl radical-induced cell death via free radical scavenging activity

The role of natural antioxidants in combating the deleterious effects of free radicals has received much attention. In the present study, the cytoprotective effects and the free radical scavenging activity of geraniin, a hydrolysable ellagitannin from Nephelium lappaceum rind, were evaluated by using various approaches. Addition of geraniin to the culture media resulted in a profound cytoprotective effect against damages induced by the peroxynitrite generator 3-morpholinosydnonimine (SIN-1), and the peroxyl radical generator 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH). Geraniin exhibits more potent cytoprotective activity than that of 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox). Geraniin exhibited potent antioxidant activity against reactive species, such as nitric oxide, superoxide anion, and chemically synthesized peroxynitrite. Kinetic analysis of reactivity against peroxyl radicals generated by AAPH revealed that geraniin possesses potent reactivity against peroxyl radicals with higher stoichiometric number than Trolox. The cytoprotective effect of geraniin was only observed when geraniin and these toxic compounds were co-existing, suggesting that geraninn exhibits cytoprotective effects via free radical scavenging activity in the extracellular fluid.     

Fuzzy Gain Scheduled Continuous Stirred Tank Reactor with Particle Swarm Optimization based PID control Minimizing Integral Square Error

In this paper, a new control scheme, the gain scheduled Particle Swarm Optimization (PSO) based PID, is proposed for a continuous stirred tank reactor (CSTR). CSTR is a highly nonlinear process that exhibits stability in certain regions and instability in some regions. Generally, PID controllers are used in these processes. Tuning of the PID controller is required to guarantee the best performance of the CSTR. The proposed scheme implements the characteristics of the PSO's global optimization to tune the PID's control parameters: k_p, k_i, k_d, to obtain the best control effect by minimizing Integral Square Error online. The PID controller parameters tuned for each region using PSO are gain scheduled using fuzzy control. Fuzzy gain-scheduling is a special form of fuzzy control that uses linguistic rules and fuzzy reasoning to determine the controller parameter transition policy for the dynamic plant subject to large changes in its operating state. Simulation results show the feasibility of using the proposed controller for the control of the dynamic nonlinear CSTR.     

Functionally modified gelatin microspheres as a growth factor’s delivery system: development and characterization

One of the advances in biotechnology has been the development of the capability to produce large quantities of highly purified polypeptides and proteins. Unfortunately, the circulatory half-lives of many of these agents are short, usually of the order of minutes and the time required for a response in tissues is usually long compared to the half-life. Hence, there is always demand for polymeric systems which can deliver the proteins for prolonged period and also to protect the molecules from degradation. The present work was attempted to develop heparin-functionalized gelatin microspheres (HMS) to deliver heparin-binding growth factors particularly for wound-healing applications. The heparin conjugation was carried out using EDC/NHS coupling protocol. Heparin-binding EGF-like growth factor (HB-EGF) was loaded in HMS and its in vitro release behaviour in an environment with or without proteases was studied. The bioactivity of the HB-EGF released from the microspheres was assessed using NIH 3T3 mouse embryonic fibroblast culture. The extent of heparin modification was found to be 1.97 μmol/g of HMS and demonstrated significant protection against enzymatic degradation and sustained release of HB-EGF for more than 10 days. The bioactivity of HB-EGF released from the HMS was retained during the observed release period. The HMS was also found to be non-toxic as determined by calcein AM fluorescent staining. The overall study suggests that the HMS could be used as a growth factor’s delivery component in tissue engineering scaffolds particularly for wound-healing applications.     

Enhancing diamond drilling performance by the addition of non-ionic polymer to the flushing media

Drilling is a most important and crucial operation in the excavation industries.With the objective of looking into the enhancement of diamond drilling performance detailed laboratory investigations were carried out on phosphate rock.The effect of Poly (Ethylene Oxide) (PEO) added to the drilling water was studied by varying machine parameters and PEO concentration.The responses were rate of penetration and torque at the bit rock interface.Slake durability tests were also performed to understand the slaking behavior of phosphate rock in PEO solutions.     

Analysis and design of digital predictive controller for PFC Cuk converter

A digital predictive control strategy for Power Factor Correction (PFC) is presented in this paper. The duty cycles required to achieve unity power factor in one half line period are calculated in advance by using a predictive algorithm and implemented using low cost PIC Microcontroller. A single stage PFC circuit controlled by these pre-calculated duty cycles can achieve sinusoidal current waveform. The output voltage of PFC circuit is regulated by an outer PI controller. A low frequency, small signal model of the rectifier is developed in order to design a PI voltage controller. A prototype of front end AC–DC converter followed by DC–DC Cuk converter controlled by a PIC Microcontroller is developed. Both the simulation and experimental results reveal that the proposed digital predictive strategy provides low THD, high power factor and better performance due to its lower calculation requirement and simple implementation.     

Decolourisation of leather dye by ozonation

Sewage and industrial effluent treatment plants are installed with primary and secondary biological treatment units to reduce the discharge of pollution load into the environment. These treatment plants normally reduce the organic load in terms of BOD but not the pollution load in terms of inorganic salts (total dissolved solids—TDS) and colour in the effluent. To eliminate the contamination of ground and surface water bodies and to conserve water sources, the regulatory authorities have taken very stringent regulations to implement zero liquid discharge (ZLD) for industrial effluents, i.e., water recovery from wastewater and reuse. It is difficult to recover water from secondary treated wastewater directly, as it does not meet the reverse osmosis feed requirements. In order to achieve the feed requirements, different tertiary treatment methods are being tried. In this study, removal of colour due to residual dyes has been attempted using ozone. The main purpose of this study is to decolourise the dye used in leather processing. Also, the effect of pH and dye concentration on dye decolourisation has been investigated. From the study it has been observed that maximum decolourisation efficiency up to 97% could be achieved for the pH values (4,7, 9 and 11) and dye concentrations (30, 65, 180 and 360 mg/L) studied.     

A study of austenitization of SG iron

Austenitization process of three SG irons with varying compositions and as cast matrix microstructure has been studied at three austenitization temperatures of 850, 900 and 950C for different time periods. Microstructure, hardness and X-ray diffraction have been used to reveal the nature of dependence of the process on austenitization temperature, time and as cast structure. The optimum austenitization time is maximum for ferritic and minimum for pearlitic matrix.     

Nanocrystalline ZnO Thin Film Synthesis Using Glycerol in Aqueous Polymeric Precursor Processing

Synthesis of high-quality ZnO thin films via simple and cost effective processing technique is a major challenge. In this work, the preparation of nanocrystalline ZnO thin films by a novel polymeric precursor processing using glycerol as chelating agent is presented. The process has advantages of being cost-effective and environment friendly. ZnO thin films were prepared by a single spin-coating deposition of aqueous polymeric precursor prepared with zinc nitrate [Zn(NO₃)₂] and glycerol as chelating agent. The thermal decomposition of polymeric precursors was studied by thermogravimetric analysis and Fourier transform infrared (FTIR) spectroscopy. Annealing of these films were performed over the range of 300°–600°C, and the effect of annealing on the degree of crystallization, surface morphology, crystallite size, and optical properties was investigated. X-ray diffraction analysis shows that the thin films are polycrystalline with wurtzite structure. The thin films are 80% dense, have crack free microstructure, and transparency of >85% in the visible region. These films exhibit absorption edge at 375 nm. On measuring at room temperature, the optical band gap energy of ZnO thin films, annealed at 450° and 600°C, was determined to be 3.295 and 3.267 eV. Room temperature photoluminescence spectra of these films show strong UV emission and a broad yellow-green emission in the range 525–600 nm. The intensity of UV emission peak increases with increase in annealing temperature that is attributed to an improvement in crystallinity.