Showing papers by "Cochin University of Science and Technology published in 2008"
TL;DR: In this paper, the authors present results from sun/sky radiometer measurements of aerosol optical characteristics carried out in New Delhi during March-June, 2006, as part of the Indian Space Research Organization's Integrated Campaign for Aerosol Radiation Budget.
Abstract: [1] We present results from sun/sky radiometer measurements of aerosol optical characteristics carried out in New Delhi during March–June, 2006, as part of the Indian Space Research Organization's Integrated Campaign for Aerosol Radiation Budget. For the first time at this site, derived are parameters such as aerosol optical depth (AOD), single scattering albedo (SSA), asymmetry parameter, Angstrom exponent, and real and imaginary refractive indices in five spectral channels. During the campaign, a consistent increase in aerosol loading from March to June with monthly average AOD values at 0.5μm of 0.55, 0.75, 1.22 and 1.18, respectively, was observed. Angstrom exponent gradually decreases from 1.28 (March) to 0.47 (June), indicating an increased abundance of coarse particles due to dust storms that transport desert dust from the Thar desert and adjoining regions. SSA at 0.5 μm is found to be in the range of 0.84 to 0.74 from March to June, indicating an increasing contribution from the mixture of anthropogenic and desert dust absorbing aerosols. Optical properties derived during the campaign are used in a radiative-transfer model to estimate aerosol radiative forcing at the surface and at the top-of-the atmosphere. A consistent increase in surface cooling is evident, ranging from −39 W m−2 (March) to −99 W m−2 (June) and an increase in heating of the atmosphere from 27 W m−2 (March) to 123 W m−2 (June). Heating rates in the lower atmosphere (up to 5 km) are 0.6, 1.3, 2.1, and 2.5K/d from March, April, May, and June 2006, respectively. Higher aerosol induced heating in the premonsoon period has been shown to have an impact on the regional monsoon climate.
250 citations
TL;DR: The distribution of species, as well as their numbers and metabolic characteristics were found to be governed by existing environmental conditions, and yeasts are more abundant in silty muds than in sandy sediments.
Abstract: Yeasts are ubiquitous in their distribution and populations mainly depend on the type and concentration of organic materials. The distribution of species, as well as their numbers and metabolic characteristics were found to be governed by existing environmental conditions. Marine yeasts were first discovered from the Atlantic Ocean and following this discovery, yeasts were isolated from different sources, viz. seawater, marine deposits, seaweeds, fish, marine mammals and sea birds. Near-shore environments are usually inhabited by tens to thousands of cells per litre of water, whereas low organic surface to deep-sea oceanic regions contain 10 or fewer cells/litre. Aerobic forms are found more in clean waters and fermentative forms in polluted waters. Yeasts are more abundant in silty muds than in sandy sediments. The isolation frequency of yeasts fell as the depth of the sampling site is increased. Major genera isolated in this study were Candida, Cryptococcus, Debaryomyces and Rhodotorula. For biomass estimation ergosterol method was used. Classification and identification of yeasts were performed using different criteria, i.e. morphology, sexual reproduction and physiological/biochemical characteristics. Fatty acid profiling or molecular sequencing of the IGS and ITS regions and 28S gene rDNA ensured accurate identification.
208 citations
TL;DR: In this article, the effect of different lubricant environments when 6061 aluminium alloy is machined with diamond-coated carbide tools was analyzed with respect to the cutting forces, surface roughness of the machined workpiece and tool wear.
198 citations
TL;DR: Improved outcome in critically ill cancer patients extended to the subgroup of patients with septic shock, and improved survival was mainly observed in patients who did not require renal replacement therapy during their stay in the intensive care unit.
Abstract: Objective:Septic shock is a severe, often terminal, complication of malignancy. For patients without malignancy, outcome from septic shock has improved with new advances in care. We wished to explore whether outcome from septic shock has similarly improved for cancer patients, with regard to impleme
175 citations
TL;DR: In this article, the authors measured real and imaginary dielectric parameters of manganese ferrite in the frequency range of 100 kHz-8 MHz at different temperatures. And they found that the dispersion and roadening properties of the vanishes of the dielectrics suggest the possibility of a distribution of relaxation time and the existence of multiple equilibrium states in manganized ferrite.
Abstract: Nanoparticles of manganese ferrite were prepared by the chemical co-precipitation technique. The dielectric parameters, namely, real and imaginary dielectric permittivity ($\varepsilon'$ and $\varepsilon"$), ac conductivity $(\sigma_{ac})$ and dielectric loss tangent $(tan \delta)$, were measured in the frequency range of 100 kHz–8 MHz at different temperatures. The variations of dielectric dispersion $(\varepsilon')$ and dielectric absorption $(\varepsilon")$ with frequency and temperature were also investigated. The variation of dielectric permittivity with frequency and temperature followed the Maxwell–Wagner model based on interfacial polarization in consonance with Koops phenomenological theory. The dielectric loss tangent and hence $\varepsilon"$ exhibited a relaxation at certain frequencies and at relatively higher temperatures. The dispersion of dielectric permittivity and roadening of the dielectric absorption suggest the possibility of a distribution of relaxation time and the existence of multiple equilibrium states in manganese ferrite. The activation energy estimated from the dielectric relaxation is found to be high and is characteristic of polaron conduction in the nanosized manganese ferrite. The ac conductivity followed a power law dependence $\sigma_{ac} = B\omega^n$ typical of charge transport assisted by a hopping or tunnelling process. The observed minimum in the temperature dependence of the frequency exponent n strongly suggests that tunnelling of the large polarons is the dominant transport process.
169 citations
TL;DR: In this paper, a dual wideband CPW-fed modified Koch fractal printed slot antenna is proposed for WLAN and WiMAX operations, which exhibits omnidirectional radiation coverage with a gain better than 2.0 dBi.
Abstract: A dual wide-band CPW-fed modified Koch fractal printed slot antenna, suitable for WLAN and WiMAX operations, is proposed in this paper. Here, the operating frequency of a triangular slot antenna is lowered by the Koch iteration technique resulting in a compact antenna. Studies on the impedance and radiation characteristics of the proposed antenna indicate that a modified Koch fractal slot antenna has an impedance bandwidth from 2.38 to 3.95 GHz and 4.95-6.05 GHz covering 2.4/5.2/5.8 GHz WLAN bands and the 2.5/3.5/5.5 GHz WiMAX bands. The antenna exhibits omnidirectional radiation coverage with a gain better than 2.0 dBi in the entire operating band. Empirical relations are deduced and compared with the results.
152 citations
TL;DR: In this article, the Raman spectra of polymethyl methacrylate (PMMA) optical fibres are recorded using a diode pumped solid state laser emitting at 532 nm and a CCD-spectrograph in the 400−3800 cm −1 range.
Abstract: Polymethyl methacrylate (PMMA) optical fibres are fabricated by a preform drawing process. The Raman spectra of PMMA fibres are recorded using a diode pumped solid state laser emitting at 532 nm and a CCD-spectrograph in the 400‐3800 cm −1 range. The variation of the Raman intensity with the length of the optical fibre is studied. Investigations are carried out on the variation of FWHM of the Raman peak at 2957 cm −1 with the length of the optical fibre and pump power. The differential scattering cross section and gain coefficient of the Raman peak at 2957 cm −1 in PMMA are calculated in relation to that of toluene.
146 citations
TL;DR: In this article, the development and testing of a new type of efficient solar dryer, particularly meant for drying vegetables and fruit, is described, which has two compartments: one for collecting solar radiation and producing thermal energy and the other for spreading the product to be dried.
143 citations
01 Dec 2008
TL;DR: LEACH-Mobile protocol has been enhanced based on a mobility metric "remoteness" for cluster head election to ensure high success rate in data transfer between the cluster head and the collector nodes even though nodes are moving.
Abstract: Cluster based protocols like LEACH were found best suited for routing in wireless sensor networks. In mobility centric environments some improvements were suggested in the basic scheme. LEACH-Mobile is one such protocol. The basic LEACH protocol is improved in the mobile scenario by ensuring whether a sensor node is able to communicate with its cluster head. Since all the nodes, including cluster head is moving it will be better to elect a node as cluster head which is having less mobility related to its neighbours. In this paper, LEACH-Mobile protocol has been enhanced based on a mobility metric "remoteness" for cluster head election. This ensures high success rate in data transfer between the cluster head and the collector nodes even though nodes are moving. We have simulated and compared our LEACH-mobile-enhanced protocol with LEACH-mobile. Results show that inclusion of neighbouring node information improves the routing protocol.
130 citations
TL;DR: The occurrence of surface plasmon resonance (SPR) bands and their evolution in the size range 5-10 nm is studied and a redshift and broadening of the plAsmon-related absorption peak was observed.
Abstract: Silver silica nanocomposites were obtained by the sol-gel technique using tetraethyl orthosilicate (TEOS) and silver nitrate (AgNO(3)) as precursors. The silver nitrate concentration was varied for obtaining composites with different nanoparticle sizes. The structural and microstructural properties were determined by x-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). X-ray photoelectron spectroscopic (XPS) studies were done for determining the chemical states of silver in the silica matrix. For the lowest AgNO(3) concentration, monodispersed and spherical Ag crystallites, with an average diameter of 5 nm, were obtained. Grain growth and an increase in size distribution was observed for higher concentrations. The occurrence of surface plasmon resonance (SPR) bands and their evolution in the size range 5-10 nm is studied. For decreasing nanoparticle size, a redshift and broadening of the plasmon-related absorption peak was observed. The observed redshift and broadening of the SPR band was explained using modified Mie scattering theory.
120 citations
TL;DR: The present regimen induced physiological postnatal testes growth and high-normal activation of Leydig and Sertoli cells and increased mean serum LH and FSH to normal or supranormal levels.
Abstract: Background: The neonatal-midinfancy surge in pulsatile gonadotropin secretion is attributable to an increase in GnRH pulse amplitude and is associated with a rapid expansion of Leydig and Sertoli cell populations with concomitant surges in testosterone, inhibin, and anti-Mullerian hormone production as well as an increase in testicular volume. Boys with congenital hypogonadotropic hypogonadism (HH) do not activate these processes. A potential cause for azoospermia and infertility in adult life is deficient proliferation of immature Sertoli cells before and during puberty due to the absence of FSH. Objective: The objective of the study was to investigate whether early postnatal continuous sc infusion of gonadotropins could mimic the physiological growth of testes and to evaluate responses of the Leydig and Sertoli cells to early gonadotropin replacement. Design and Methods: Two neonates (P1 with hypotuitarism and P2 with HH) with micropenis and microorchidism were treated for 6 months with high doses of re...
TL;DR: In this paper, the spectral and nonlinear optical properties of ZnO-Ag nanocomposites prepared by colloidal chemical synthesis were analyzed and shown to have self-defocusing nonlinearity and good nonlinear absorption behavior.
TL;DR: In this paper, an analysis of sedimentation in the Konkan-Kerala Basin, coupled with a mass balance study, and numerical modelling of flexural responses to onshore denudational unloading and offshore sediment loading in order to test competing conceptual models for the development of high elevation passive margins.
Abstract: The Konkan and Kerala Basins constitute a major depocentre for sediment from the onshore hinterland of Western India and as such provide a valuable record of the timing and magnitude of Cenozoic denudation along the continental margin. This paper presents an analysis of sedimentation in the Konkan–Kerala Basin, coupled with a mass balance study, and numerical modelling of flexural responses to onshore denudational unloading and offshore sediment loading in order to test competing conceptual models for the development of high‐elevation passive margins. The Konkan–Kerala Basin contains an estimated 109 000 km3 of Cenozoic clastic sediment, a volume difficult to reconcile with the denudation of a downwarped rift flank onshore, and more consistent with denudation of an elevated rift flank. We infer from modelling of the isostatic response of the lithosphere to sediment loading offshore and denudation onshore infer that flexure is an important component in the development of the Western Indian Margin. There is evidence for two major pulses in sedimentation: an early phase in the Palaeocene, and a second beginning in the Pliocene. The Palaeocene increase in sedimentation can be interpreted in terms of a denudational response to the rifting between India and the Seychelles, whereas the mechanism responsible for the Pliocene pulse is more enigmatic.
TL;DR: In this article, the authors used ArcGIS version 8.3 to assess the susceptibility of landslides in parts of Western Ghats, Kerala, India, using a geographical information system (GIS).
Abstract: The purpose of this study is to assess the susceptibility of landslides in parts of Western Ghats, Kerala, India, using a geographical information system (GIS). Landslide inventory of the area was made by detailed field surveys and the analysis of the topographical maps. The landslide triggering factors are considered to be slope angle, slope aspect, slope curvature, slope length, distance from drainage, distance from lineaments, lithology, land use and geomorphology. ArcGIS version 8.3 was used to manipulate and analyse all the collected data. Probabilistic-likelihood ratio was used to create a landslide susceptibility map for the study area. The result was validated using the Area under Curve (AUC) method and temporal data of landslide occurrences. The validation results showed satisfactory agreement between the susceptibility map and the existing data on landslide locations. As the result, the success rate of the model was (84.46%) and the prediction rate of the model was (82.38%) shows high prediction accuracy. In the reclassified final landslide susceptibility zone map, 5.68% of the total area is classified as critical in nature. The landslide susceptibility map thus produced can be used to reduce hazards associated with landslides and to land cover planning.
TL;DR: In this paper, the effect of lithium borosilicate (LBS) glass addition on sintering temperature and microwave dielectric properties of forsterite was investigated.
TL;DR: In this paper, a porosity-filled polytetrafluoroethylene (PTFE) composite was used as the matrix and the dispersion of CeO2 in the composite was varied up to 0.6 by volume fraction, and the dielectric properties were studied at 1 and microwave frequencies.
Abstract: Cerium oxide (CeO2) filled polytetrafluoroethylene (PTFE) composites prepared by powder processing technique for microwave substrate application is presented in this paper. The PTFE is used as the matrix and the dispersion of CeO2 in the composite is varied up to 0.6 by volume fraction, and the dielectric properties were studied at 1 MHz and microwave frequencies. The relative permittivity and dielectric loss increased with increase in CeO2 content. For 0.6 volume fraction loading of the ceramic, the composite has ɛr of 5 and tan δ of 0.0064 at 7 GHz. Different theoretical approaches have been employed to predict the effective permittivity of composite systems and the results were compared with that of experimental data. The serial mixing model shows good correlation with the experimental results.
TL;DR: O adoptive transfer of BMDCs reversed sepsis-induced immune dysfunction in a relevant model of secondary P. aeruginosa pneumonia, and the mechanism of action did not involve enhanced antibacterial activity, but occurred by dampening the pulmonary inflammatory response.
Abstract: Host infection by pathogens triggers an innate immune response leading to a systemic inflammatory response, often followed by an immune dysfunction which can favor the emergence of secondary infections. Dendritic cells (DCs) link innate and adaptive immunity and may be centrally involved in the regulation of sepsis-induced immune dysfunction. We assessed the contribution of DCs to lung defense in a murine model of sublethal polymicrobial sepsis (cecal ligature and puncture, CLP). In this model, bone marrow-derived DCs (BMDCs) retained an immature phenotype, associated with decreased capacity of IL-12p70 release and impaired priming of T cell lymphocytes. Eight days after CLP surgery, we induced a secondary pulmonary infection through intratracheal instillation of 5 x 10(6) CFUs of Pseudomonas aeruginosa. Whereas all sham-operated mice survived, 80% of post-CLP mice died after secondary pneumonia. Post-CLP mice exhibited marked lung damage with early recruitment of neutrophils, cytokine imbalance with decreased IL-12p70 production, and increased IL-10 release, but no defective bacterial lung clearance, while systemic bacterial dissemination was almost constant. Concomitant intrapulmonary administration of exogenous BMDCs into post-CLP mice challenged with P. aeruginosa dramatically improved survival. BMDCs did not improve bacterial lung clearance, but delayed neutrophil recruitment, strongly attenuated the early peak of TNF-alpha and restored an adequate Il-12p70/IL-10 balance in post-CLP mice. Thus, adoptive transfer of BMDCs reversed sepsis-induced immune dysfunction in a relevant model of secondary P. aeruginosa pneumonia. Unexpectedly, the mechanism of action of BMDCs did not involve enhanced antibacterial activity, but occurred by dampening the pulmonary inflammatory response.
TL;DR: In this paper, the optical and nonlinear optical properties of the glasses were investigated and it was found that thermal annealing up to the glass softening temperature makes the samples behave like saturable absorbers, while annaling at higher temperatures makes them behave like optical limiters.
TL;DR: In this article, the first use of polystyrene-supported poly(amidoamine) (PAMAM) dendrimers as heterogeneous basic organocatalysts for carbon-carbon bond formation was described.
TL;DR: Nickel substituted copper chromite spinels (Cu 1− x Ni x Cr 2 O 4 ) were prepared by homogeneous co-precipitation method as discussed by the authors and the materials were characterized in detail by X-ray diffraction, BET surface area, scanning electron microscopy, energy dispersive Xray analysis and FTIR spectroscopy.
TL;DR: This study confirmed the burden of HCV infection in French HIV-infected patients and described for the first time in France the epidemiological characteristics of HIV-HBV co-infection, and stresses the severity of liver disease related to HCV in HIV- infected population.
Abstract: Our objective was to estimate the prevalence of HCV and HBV co-infection among HIV-infected adults in France and describe the epidemiological characteristics of co-infected patients and their clinical management. A one-day national cross-sectional survey was conducted in 2004. A random and proportional probability sample design was used, based on the number of AIDS cases reported since 1999 by hospital wards. Weighted estimations were computed. HIV-infected adults (out/in-patients) were included after consent. Data were collected on demographic criteria, HIV, HCV and HBV infections, as well as on antiviral therapies. Overall, 1849 HIV-infected patients were included. The prevalence of anti-HCV or HCV RNA positivity (HCV co-infection) was 24.3% [95% confidence interval (CI): 21.3-27.6] and varied from 3.1% in men who had sex with men to 92.8% in injecting drug users (IDUs). The prevalence of positive HCV RNA was 17.0% [95% CI:14.7-19.4]. The prevalence of HBs antigen (Ag) or HBV DNA positivity was 7.0% [95% CI: 5.9-8.1] and varied with the continent of birth from 2.1% in Northern Africa to 10.8% in sub-Saharan Africa. The prevalence of HIV-HCV-HBV co-infection was 1.6% [95% CI: 1.0-2.4], mostly IDUs (83.3%). A severe liver disease (cirrhosis or hepatocellular carcinoma) was diagnosed in 24.7% of the positive HCV RNA patients. This study confirmed the burden of HCV infection in French HIV-infected patients and described for the first time in France the epidemiological characteristics of HIV-HBV co-infection. Furthermore, it stresses the severity of liver disease related to HCV in HIV-infected population.
TL;DR: In this paper, a series of alkylammonium salts as Bronsted acidic ionic liquids were used as catalysts and mediums in the esterification reaction of acetic acid with 1-octanol.
Abstract: Esterification of acetic acid with 1-octanol was studied using a series of alkylammonium salts as Bronsted acidic ionic liquids. The following ionic liquids were prepared and used as catalysts and mediums in the esterification reaction; [Et3NH][HSO4], [Et3NH][H2PO4], [Et3NH][BF4], [Et3NH][p-CH3C6H4SO3], [Et2(PhCH2)NH][HSO4], [n-Bu3NH][HSO4], [n-Oct3NH][HSO4], [Et2NH2][HSO4], [Et2NH2][H2PO4], [Et2NH2][BF4], [i-Pr2NH2][HSO4], [EtNH3][HSO4], [EtNH3][H2PO4], and [EtNH3][BF4]. Higher acidity of the anion in the ionic liquid resulted in high yield of the ester. Yield of the ester decreased with increase in the size of the cation. There was no phase separation in the reactions where size of anion and/or cation was bigger.
TL;DR: The spectral and nonlinear optical properties of ZnO-TiO(2) nanocomposites prepared by colloidal chemical synthesis are presented and they show self-defocusing nonlinearity and good nonlinear absorption behaviour.
TL;DR: The results showed that B. monnieri treatment to epileptic rats significantly brought the reversal of the down-regulated mgluR8 gene expression toward control level, suggesting the clinical significance of corrective measures for epileptic and hypoxic management.
Abstract: The experiments were designed to study the glutamate gene expression during epilepsy in adult and hypoxic insult to brain during the neonatal period and the therapeutic role of neuroprotective supplements. We investigated the role of metabotropic glutamate-8 receptor (mGluR8) gene expression in cerebellum during epilepsy and neuroprotective role of Bacopa monnieri extract in epilepsy. We also studied the effect of NMDA receptor 1 (NMDAR1) gene expression during neonatal hypoxia and therapeutic role of glucose, oxygen and epinephrine supplementation. During epilepsy a significant down-regulation (P < 0.01) of mGluR8 gene expression was observed which was up-regulated (P < 0.05) near control level after B. monnieri treatment which is supported by Morris water maze experiment. In hypoxic neonates we observed up-regulation (P < 0.001) of the NMDAR1 gene expression whereas glucose and glucose + oxygen was able to significantly reverse (P < 0.001) the gene expression to near control level when compared to hypoxia and epinephrine treatment which was supported by open field test. Our results showed that B. monnieri treatment to epileptic rats significantly brought the reversal of the down-regulated mgluR8 gene expression toward control level. In neonatal rats, hypoxia induced expressional and functional changes in the NMDAR1 receptors of neuronal cells which is corrected by supplementation of glucose alone or glucose followed by oxygen during the resuscitation to prevent the glutamate related neuronal damage. Thus, the results suggest the clinical significance of corrective measures for epileptic and hypoxic management.
TL;DR: A significant vertebral antifracture efficacy of strontium ranelate is demonstrated in young postmenopausal women aged 50–65 years with severe osteoporosis and the efficacy of this antiosteoporotic treatment to prevent vertebral fractures is confirmed, whatever the age of the patient.
Abstract: Early osteoporotic fractures have a great impact on disease progression, the first fracture being a major risk factor for further fractures. Strontium ranelate efficacy against vertebral fractures is presently assessed in a subset of women aged 50-65 years.
01 Jan 2008
TL;DR: Best management practices for the aquaculture industry, considering environmental, economic and social sustainability, have been established, and rules or statements suggest that intensification will always lead to the production of more wastes or to a reduction of animal welfare should be avoided.
Abstract: Much has been said on the need to practice aquaculture in a sustainable manner, preferably without jeopardizing the environment (Naylor, et al. 2000 and FAO 1997). As a result, best management practices for the aquaculture industry, considering environmental, economic and social sustainability, have been established (e.g. www.gaalliance.org/bap.html). Standards of some organizations for organic farming restrict stocking density and maximum pond biomass per unit surface area. For example, to produce organic shrimps, less than 15 postlarvae (PL) per square meter should be stocked with shrimp biomass always remaining below 800kg/ha (e.g. Naturland standards 2004; www.naturland.de/ englisch/n2/NL-Stand-Aquaculture_01-2005. pdf). These rules were mainly put forward to protect shrimp health and welfare, and to avoid the development of diseases. Naylor et al. (2000) stated that “intensification implies increasing the density of individuals, which requires greater use and management of inputs and greater generation of waste products”. Such rules or statements suggest that intensification will always lead to the production of more wastes or to a reduction of animal welfare, which should be avoided.
TL;DR: In this paper, the optical and carrier transport properties of amorphous transparent zinc indium tin oxide ZITOa-ZITO thin films and the characteristics of the thin-film transistors TFTs were examined as a function of chemical composition.
Abstract: The optical and carrier transport properties of amorphous transparent zinc indium tin oxide ZITOa-ZITO thin films and the characteristics of the thin-film transistors TFTs were examined as a function of chemical composition. The as-deposited films were very conductive and showed clear free carrier absorption FCA. The analysis of the FCA gave the effective mass value of 0.53 me and a momentum relaxation time of 3.9 fs for an a-ZITO film with Zn:In:Sn = 0.35:0.35:0.3. TFTs with the as-deposited channels did not show current modulation due to the high carrier density in the channels. Thermal annealing at 300°C decreased the carrier density and TFTs fabricated with the annealed channels operated with positive threshold voltages VT when Zn contents were 25 atom % or larger. VT shifted to larger negative values, and subthreshold voltage swing increased with decreasing the Zn content, while large on‐off current ratios 10 7 ‐10 8 were kept for all the Zn contents. The field effect mobilities ranged from 12.4 to 3.4 cm 2 V
TL;DR: In this article, the authors report the third order nonlinear optical properties of ZnO thin films deposited using self assembly, sol gel process as well as pulsed laser ablation by z scan technique.
TL;DR: In this paper, a planar antenna for DCS-1900/PCS/PHS, WCDMA/IMT-2000, and WLAN applications is presented.
Abstract: A compact dual-band planar antenna developed for DCS-1900/PCS/PHS, WCDMA/IMT-2000, and WLAN applications is presented. The proposed antenna consists of a flared monopole with an additional sleeve for dual-band applications. The overall size of the antenna is 40 mm times 25 mm times 1.6 mm including the Finite Ground CPW feeding mechanism. The antenna operates in two frequency bands from 1.83 to 2.34 GHz and 3.23 to 5.76 GHz covering DCS-1900/PCS/PHS, WCDMA/IMT-2000, and WLAN bands. Simulation results along with measurements of the prototyped antenna are presented and discussed.
TL;DR: The use of cardanol, a renewable natural resource, in place of a phenol or diphenol, in the synthesis of two different epoxy systems has been studied in this paper.
Abstract: The use of cardanol, a renewable natural resource, in place of a phenol or diphenol, in the synthesis of two different epoxy systems has been studied in this work. Cardanol, prepared by the distillation of cashew nut shell liquid (CNSL), was epoxidised using epichlorohydrin in presence of caustic soda catalyst at different reaction intervals and the products were characterized by spectroscopy, gel-permeation chromatography and by determining the epoxide equivalent. The epoxide equivalent increased sharply with time of epoxidation and reached almost a limiting value around 9 h. Cardanol, being less reactive, undergoes epoxidation to a smaller extent than phenol or bisphenol. Although these epoxy compounds do not form cross-linked networks due to being mono-functional, they are found to be effective in producing relatively flexible systems when reactive blended with commercial DGEBA. Co-epoxides containing bisphenol A and cardanol in varying molar compositions were also synthesised and characterised. Introd...