SEM Images Research Articles

Thickness effects on the physical characterization of nanostructured CuO thin films for hydrogen gas sensor

In these studies, radio frequency (RF) magnetron sputtering was used to produce nanostructured CuO thin films on glass bases with different thicknesses of (250, 300, and 350 nm). X-ray diffraction (XRD) analysis of these films revealed a polycrystalline structure with a preferred peak along the (111) plane. The Scherrer formula was used to compute the grain size. It was found that the average grain sizes are 10.78 nm, 11.36 nm, and 11.84 nm for film thicknesses of 250, 3000, and 300 nm, respectively, while the dislocation density and strain values decline. The surface roughness decreased from 9.30 nm to 4.71 nm as the thickness increased, according to atomic force microscopy (AFM) data. As the thickness of the film grew, the root mean square (RMS) roughness likewise decreased from 9.18 nm to 4.29 nm. The homogenous, semi-spherical structure comprises uniformly distributed particles, as demonstrated by SEM images. The optical properties of the grown films showed that the absorption coefficient considerably increased with film thickness. Transmittance, band gap, refractive index, and extinction coefficient all decrease with increasing film thickness. The hydrogen gas measurements, indicated a reduction in sensitivity as the thickness and gas concentration increased at 30°C.

Instant green synthesis: obtaining stable nanoparticles and understanding the extract's behavior in the particle formation mechanism

Numerous plant extracts are abundant in biomolecules that can be employed in the biogenic synthesis of metallic nanoparticles owing to their potent reducing capabilities. The mechanism by which biomolecules act as reducers and expedite the reduction of silver ions remains poorly understood. This study presents an instantaneous and environmentally friendly synthesis of silver nanoparticles (AgNPs) using varying concentrations of commercially available green tea and concentrations of a dextrose-reducing solution. The AgNPs formed instantaneously, likely due to the competitive reaction between the polyphenols present in green tea and the dextrose. The best AgNPs produced using a diluted green tea solution at a concentration of 0.05 g of tea/ml and 100 μl of dextrose solution exhibited high stability over a period of 90 days, as confirmed by UV–vis spectroscopy and dynamic light scattering. The results of antioxidant properties from diluited tea showed 2,2-diphenyl-1-picrylhydrazyl (DPPH) 0.013 ± (0.1) μmol Trolox Equivalent Anyioxidant Capacity (TEAC) TEAC/g, Ferric Reducing Antioxidant Power (FRAP) 10.3 ± (0.1) μmol TEAC/g and Total Polyphenol Content (TPC) 0.12 ± (.001) μgGAE(Galic Acid Equivalent)/g). The resulting nanoparticles are extremely small, measuring approximately 30 to 50 nm in size, and exhibit a spherical morphology as evidenced by SEM imaging. The plasmon bandwidth is better in more diluted tea and higher proportions of dextrose added than the others condition of synthesis. Probably, the results of 2nd extraction of green tea diluted can be evidence that phenolic compounds, mainly, caffeine and gallic acid, are contributing to forming and stabilizing the silver nanoparticles. This fundamental knowledge showed the method employed is ecologically sound and adheres to green principles.

Evaluation of the Performance of Pervious Concrete Inspired by CO2-Curing Technology

Urban runoff is acidic in nature and mainly consists of heavy metals and sediments. In this study, the pervious concrete samples were cured in a CO2-rich environment and their performance under runoff conditions was evaluated by passing different solutions containing clay particles, heavy metal ions, and acid species. The compressive strength of these samples was reduced by up to 14% when they were cured in water instead of a CO2 environment. Heavy metal ions, including lead and zinc, in the simulated runoff were adsorbed in these pervious concrete samples by up to 96% and 80% at the end of the experiment, but the acid species in this runoff could leach calcium ions from the cement components during passage. Clay particles in the runoff were trapped in the flow channels of samples, which marginally reduced the percolation rate by up to 14%. Concrete carbonation reduced the release of calcium ions under runoff conditions, and zinc removal was relatively lower because of the nonavailability of hydroxyl sites in the interconnected pore structure. The weight and strength losses in the carbonated concrete samples were relatively lower at the end of the acid storage experiment, suggesting that CO2 curing reduces cement degradation in aggressive chemicals. The SEM and tomography images revealed the degraded microstructure, while the XRD results provided data on the mineralogical changes. CO2 curing improves the strength gain and service life of pervious concrete in runoff environments.

PREPARATION AND PROPERTIES OF CHITIN HYDROGEL APPLIED AS MOISTURE-SUPPORTER FOR SEED GERMINATION

In this study, chitin was chemically extracted from shrimp shell, and then used for the development of a chitin hydrogel-based moisture supporter for hydroponic systems. Here, the chitin hydrogel was prepared at different concentrations of lithium chloride (LiCl), varying from 5 to 9%, in N,N-dimethylacetamide (DMAc) at room temperature. The results revealed that, while most characteristic functional groups of the chitin segment remained intact in all chitin hydrogels, higher levels of LiCl in DMAc led to a reduction in both crystalline index and equilibrium water content in the resulting chitin hydrogel. In a seed germination experiment, it was observed that the chitin hydrogel containing 5% LiCl concentration exhibited superior results in terms of root, stem, and leaf length, compared to other concentrations. Therefore, the chitin hydrogel was an effective moisture-supporter for seed germination and early plant development, compared conventional soil used as control. Moreover, SEM images illustrated that the chitin hydrogel possessed a pliable structure, indicating improved degradation when subjected to composting over a 15-day period.

Comparative study on reduction behaviors of low- and high-grade fired hematite iron ore pellets in coal

The reduction behaviors of fired Ramallakota (low-grade) and Bolani (high-grade) iron ore pellets were studied isothermally at temperatures of 1123, 1173 and 1223 K in non-coking coal. The degree of reduction progressed with the rise in reduction temperature and time. Ramallakota iron ore pellets exhibited relatively higher reduction rates than Bolani iron ore pellets reduced under identical conditions due to their higher porosity and gangue contents. Comparison of XRD patterns confirmed almost complete reduction in Ramallakota iron ore pellets at all the studied reduction temperatures in a much shorter period. Fayalite and hercynite formations were observed in both the types of reduced iron ore pellets with higher intensities in the pellets of Ramallakota iron ore. SEM images revealed relatively more growth of iron whiskers in reduced Bolani high-grade iron ore pellets. The apparent activation energy values for the reduction of studied iron ore pellets by coal were calculated to be in the range 14–20 kJmol−1, while pellets reduced in coal char under identical conditions exhibited relatively higher values owing to their slower reduction rates.

Influence of Hydroxyapatite Content on Physical and Rheological Properties of Chitosan-based Scaffold

Chitosan-based scaffolds offer significant potential in tissue engineering and regenerative medicine. Whilst exhibiting great bio-regenerative and biocompatible properties, their mechanical properties remain quite poor. The presented research is focused on the modification of macroporous chitosan scaffolds with various amounts of bioactive ceramics (hydroxyapatite) and its influence on the physical and rheological properties of the composite scaffold. Chitosan/hydroxyapatite composite scaffolds with a highly porous microstructure have been prepared by suspending hydroxyapatite (HAp) particles into the chitosan matrix. According to SEM imaging, homogeneous dispersion of the inorganic phase in a chemically-crosslinked chitosan matrix had been achieved. The obtained composite scaffolds exhibited lower swelling capacity with respect to pure chitosan after 24 h of incubation in Hanks’ balanced salt solution. Rheological measurements show an increase in storage and loss modulus indicating an improvement in mechanical properties under shear stress. Furthermore, no significant change in loss factor (tanδ) was observed indicating no change in composite viscoelastic properties with an increase in HAp content.

Clinical effect of chlorhexidine and sodium fluoride on corrosion behavior and surface topography of nitinol orthodontic archwires

BackgroundAlterations in the mechanical properties of the materials utilized in orthodontic appliances could affect the working properties of the appliances, thereby affecting clinical progress and outcome. Numerous studies have confirmed the correlation between alloy corrosion and raised surface roughness, which has a direct impact on the working characteristics of orthodontic archwires.MethodsThirty nickel-titanium (NiTi) orthodontic archwires were utilized in this study. Patients were randomly selected and allocated into three groups according to the randomization plan; (The control group): subjects practiced regular oral hygiene; (The fluoride group): subjects used fluoride for intensive prophylaxis; (The chlorhexidine group): subjects used chlorhexidine. Representative samples were evaluated by SEM, and then SEM images with high resolution were examined using Image J software to determine the surface roughness and obtain the results for further statistical analysis.ResultsOur findings indicated a significant difference was found between the three groups regarding the anterior and posterior parts between the control and the two other groups and a non-significant difference between NaF and CHX groups. Overall, the p-value for group comparisons was 0.000 for both parts, indicating a highly significant difference especially between the control and NaF groups.ConclusionMouthwashes containing sodium fluoride demonstrated more significant surface alterations than the control and CHX groups and should be prescribed in accordance with orthodontic materials to reduce side effects.

Gadolinium Schiff-base complex on nanocomposite of graphene oxide magnetic nanoparticles as a robust, reusable and chemoselective nanocatalyst in the C–C coupling reactions

Graphene is an important phase of carbon, which is easily available and oxidable to graphene oxide with a variety of applications. Therefore in this work, graphene oxide (GO) was synthesized, and further it was magnetized by nickel magnetic nanoparticles. The surface of graphene oxide magnetic nanoparticles (Ni-GO MNPs) was modified with (3-aminopropyl)triethoxysilane (APTES). On the other hand, (3,4-bis(−(2-hydroxybenzylidene)amino)phenyl)(phenyl)methanone Schiff-base ligand (bis(HBAPM)) was synthesized using condensation of salicylaldehyde and 3,4-diaminobenzophenone. In the next step, bis(HBAPM) was immobilized on the surface of modified Ni-GO MNPs toward synthesis of immobilized Schiff-base on Ni-GO MNPs (bis(HBAPM)@Ni-GO MNPs) as a heterogeneous Schiff-base ligand. In the final step, the gadolinium catalyst was stabilized on its surface (Gd-bis(HBAPM)@Ni-GO MNPs) as a robust, reusable, efficient, chemoselective, and novel nanocatalyst. Gd-bis(HBAPM)@Ni-GO MNPs were characterized by nitrogen adsorption/desorption, FT-IR, SEM imaging, EDS analysis, WDX analysis, XRD, and VSM analysis. After the characterization of Gd-bis(HBAPM)@Ni-GO MNPs, its catalytic performance was employed as a highly practical, retrievable, stable, and hybrid organic–inorganic catalyst in the carbon–carbon coupling of the Suzuki reaction. Due to the recoverability and heterogeneous nature of Gd-bis(HBAPM)@Ni-GO MNPs, it can recycled again for 5 runs.

Investigation of tribological performance of hydrothermal carbon by pin-on-disc test and warm deep drawing process

In this study, the synthesis of hydrothermal carbon (HTC) lubricant and its usability as a lubricant under hot industrial conditions were investigated. In this context, the characterization of HTC produced from organic sources at low cost and in a short time was performed, and its tribological performance was analysed in detail. HTC produced by the hydrothermal carbonization method was characterized through SEM images and EDS analysis. To determine the effect of HTC on friction at different temperatures, HTC was subjected to a pin-on-disc wear test with AA5754 material. The effect of various lubricants, temperatures, blank holder pressure, and forming speed parameters on the forming force for the analysis of the tribological effect of HTC on deep drawing processes were statistically analysed. The performance of HTC was compared with Teflon, fullerenes, graphene, and carbon nanotube (CNT) materials. According to the results obtained from wear tests, the lowest friction coefficient value was achieved in the presence of fullerenes as the lubricant, and as the temperature increased, the friction coefficient decreased. It was observed that HTC exhibited lower performance in the wear test compared to fullerenes due to oxidation. When the effect of deep drawing parameters on the forming force was analysed, it was concluded that the most effective parameters were temperature (72.32%) and lubricant (20.89%). According to the S/N analysis results, the minimum forming force was obtained under the conditions of solid Teflon lubricant, 250 °C temperature, 15-bar blank holder pressure, and 2 mm/s forming speed. The tribological performance difference between HTC and Teflon is at the 1% level. The results demonstrate the potential industrial usability of HTC as a lubricant.

Reinforcing effects of ground tyre rubber on physical, mechanical, and thermal properties of polyethylene terephthalate

This study examines the use of waste and recyclable polyethylene terephthalate (rPET) along with micro-sized ground tire rubber (GTR) to produce a polymer matrix composite (PMC) material. The PMC materials are made in a Twin-screw extruder, with different ratios of rPET to GTR ranging from 90:10 to 50:50. In order to assess the performance of the newly created rPET-GTR matrix composite materials, the physical, mechanical properties are empirically observed. The thermal properties and crystallinity (Xc) of PMC materials are analysed using DSC. SEM and microscopic imaging are used to determine the characteristics of rPET-GTR composite materials, including elemental compositions like carbon, oxygen, and silicon. The functional group and chemical structure are confirmed through IR spectra analysis using FTIR techniques. The inclusion of micro-sized GTR has shown a significant effect on the physical (density = 1.306 - 1.208 g/cm3, water absorption = 1.76%–10.74%, and melt flow index = 8.12 - 12.79 gm/10 min), mechanical (tensile strength = 52.78 – 73.58 MPa, impact strength = 110.64 - 138.44 J/m, hardness = 56.14 - 76.37, and flexural modulus = 66.23 - 106.32 MPa), and thermal (melting temperature = 220.25°C–192.57°C, Xc = 20.30 to 30.58%) properties of rPET. These studies all work together to improve the performance of waste rPET and GTR materials by repurposing them. It helps to promote sustainability, cost-effectiveness, and expands the range of applications (automotive parts, building materials, sports equipment, electrical insulation and prosthetics) for rPET-based composites with potential uses in the polymer industries.

Effect of Mercerization on Mechanical Properties of <i>Grewia Optiva </i>Natural Fiber Polymer Composites

The concerns towards sustainable development have triggered the need of adopting biodegradable products in different applications. The natural fibers are being widely explored in the field of composites for various applications. Sustainable architecture is also seeking the research and development of new materials to minimize the negative environmental effect of the traditional structural materials. A bast fiber obtained from Grewia Optiva (G.O.) tree is abundantly available in the sub-Himalayan terrains and is still underutilized in the field of biocomposites. The promotion of G.O. fiber in fabrication of biocomposites may give a source of income and employment to rural hilly populations. This research work utilizes the G.O. fiber collected from the Okhalkanda block of Nainital district of Uttarakhand to develop biocomposites. The effect of mercerization on the water absorption behavior and mechanical properties has been also studied. It is found that the treatment of fibers with NaOH reduces the water absorption tendency of G.O. Natural Fiber Reinforced Biocomposites (NFRB) upto 41.05% and the mechanical properties are also improved by appreciable amount. The tensile and flexural strength obtained are 141.45 MPa and 109.84 MPa respectively for mercerized fiber reinforcement. Impact strength and mode-I fracture toughness have been recorded as 11.97 KJ/m2 and 1.85 MPa√m respectively. SEM images of fractured surfaces indicate good bonding of mercerized fibers as compared to untreated fibers with epoxy matrix. Hence the Grewia Optiva biocomposites have potential to be used in different architectural applications like wall panels, false ceilings, doors, windows, etc.

Structural, Optical, and Thermal Properties of PVA/SrTiO3/CNT Polymer Nanocomposites.

Successful preparation of PVA/SrTiO3/CNT polymer nanocomposite films was accomplished via the solution casting method. The structural, optical, and thermal properties of the films were tested by XRD, SEM, FTIR, TGA, and UV-visible spectroscopy. Inclusion of the SrTiO3/CNT nanofillers with a maximum of 1 wt% drastically improved the optical and thermal properties of PVA films. SrTiO3 has a cubic crystal structure, and its average crystal size was found to be 28.75 nm. SEM images showed uniform distribution in the sample with 0.3 wt% of SrTiO3/CNTs in the PVA film, while some agglomerations appeared in the samples of higher SrTiO3/CNT content, i.e., at 0.7 and 1.0 wt%, in the PVA polymer films. The inclusion of SrTiO3/CNTs improved the thermal stability of PVA polymer films. The direct and indirect optical band gaps of the PVA films decreased when increasing the mass of the SrTiO3/CNTs, while the single-oscillator energy (E0) and dispersion energy (Ed) increased. The films' refractive indices were gradually increased upon increasing the nanofillers' weight. In addition, improvements in the optical susceptibility and nonlinear refractive indices' values were also obtained. These films are qualified for optoelectronic applications due to their distinct optical and thermal properties.

Physical and sensing characterization of nanostructured Ag doped TiO2 thin films

On glass substrates, silver (Ag) doped Titanium dioxide (TiO2) films at varied levels of concentrations (0, 2, and 4) % wt were synthesized by chemical spray pyrolysis (CSP). As per the X-ray diffraction pattern, the only phases present in the sample were anatase and rutile TiO2. Using AFM, it was discovered that the TiO2 thin films were smooth and compact; however, the surface roughness increases as the dopant amount decreases. SEM images display TiO2 films. Surface transformation is evident with uniform spherical nanograins after Ag doping. The optical characteristics of wavelength range (300-900) nm have been investigated using absorbance and transmittance spectra. The results revealed that the films have a 65-75 % transmittance in VIS-NIR spectra for all films. The allowable direct electronic transitions have (3.15-3.25) eV energy gaps. At 250 ppm, the NH3 gas sensor exhibited increased resistance, indicating heightened sensitivity. Sensitivity decreases with concentration increases to 0 %, 2 %, and 4 % of Ag for NH3 gas. Reduction observed: 18.4% to 4.6% (50 ppm), 20.7% to 6.8% (150 ppm), and 25.9% to 8.2% (250 ppm).

Dual functionality of NiFe2O4 nanoparticles as a fertilizer and supercapacitor

Nanoparticles-based fertilizers can supply nutrients more effectively to the crops that can improve agricultural productions. Ferrite nanoparticles can replace the conventional iron fertilizers. Iron is more essential for plant growth and itsdeficiency mostly affects the cellular activities. Nickel isa constituent of plant enzymes like urease that converts nitrogen into useable ammonia inside the plant. It also prevents the accumulation of toxic levels of urea in plant tissues. In spinel ferrites, Nickel ferrite is considered for many applications because of its superior properties. NiFe2O4nanoparticles exhibit excellent electrochemical performance with highest capacity. NiFe2O4 nanoparticle (NP) has been successfully synthesized using sol–gel technique and its characteristics are analysed by XRD, FTIR and SEM techniques. XRD confirms the cubic-spinel structure with crystallite size of 23.98 nm. FT-IR spectrum shows the presence of functional groups in the sample. The SEM images shows the morphology and size of the obtained nanoparticles. The results of seed priming account of nickel ferrite NPs in the growth of rice and black gram have been explored. Seeds of rice and black gram are primed with various concentrations of NiFe2O4 NPs (0, 5, 10, 15, and 20 mgL−1) for 24 h by continuous aeration. Plant height, spike length, dry weights of roots, shoots, grains, and spikes are greater with synthesized NPs, especially in higher rates of NPs. The results confirm that NiFe2O4 NPs made significant influence in the growth of rice and black gram. NiFe2O4 NPs are developed as electrode for supercapacitor and tested their charge storage ability by the electrochemical techniques. It exhibits specific capacitance of 360 Fg−1 and cyclic retention of 98.9 % even after 5000 GCD cycles. Bifunctional performance of NiFe2O4 NPs is demonstrated as nano fertilizer and supercapacitor which is the need for fertilizer and energy storage devices industries.

Review of Senopterina Macquart (Diptera, Platystomatidae) from Brazil, with description of two new species

A review of Senopterina Macquart, 1835, a Nearctic and Neotropical genus with 21 species, is presented. Senopterina brevipes (Fabricius, 1805), the type species of the genus, and S. macularis (Fabricius, 1805), are redescribed. Two new species are listed for Brazil: S. canina sp. nov., and S. flavifemoris sp. nov., from the following states: Amapá, Goiás, Maranhão, Mato Grosso, Mato Grosso do Sul, Paraná, Rondônia and Tocantins. SEM images of the male and female terminalia of the redescribed species and of the new species are presented. An updated identification key to species is also provided.

Tuning the water interlayer spacer of microwave-synthesized holey graphene films towards high performance supercapacitor application

Abstract Graphene-based electrodes have been extensively investigated for supercapacitor applications. However, their ion diffusion efficiency is often hindered by the graphene restacking phenomenon. Even though holey graphene (hG) is fabricated to address this issue by providing ion transport channels, those channels could still be blocked by densely stacked graphene nanosheets. To tackle this challenge, this research aims at improving the ion diffusion efficiency of microwave-synthesized hG films by tuning the water interlayer spacer towards the improved supercapacitor performance. By controlling the vacuum filtration during graphene-based electrode fabrication, we obtain dry films with dense packing and wet films with sparse packing. The SEM images reveal that 20 times larger interlayer distance is constructed in the wet film compared to that in the dry counterpart. The hG wet film delivers a specific capacitance of 239 F g−1, ∼82% enhancement over the dry film (131 F g−1). By an integrated experimental and computational study, we quantitatively show that the interlayer spacing in combination with the nanoholes in the basal plane dominates the ion diffusion rate in hG-based electrodes. Our study concludes that novel hierarchical structures should be further considered even in hG thin films to fully exploit the superior advantages of graphene-based supercapacitors.

Boosted regeneration of coked SAPO-34 catalyst in MTO fluidized bed reactor by diluted air at elevated temperatures

SAPO-34 zeolite as an excellent catalyst for methanol-to-olefins (MTO) reaction suffers rapid deactivation by prevalent coking. Herein, regeneration of coked-SAPO-34 in a fluidized-bed reactor was successfully intensified by altering temperature (550–650 °C) and oxygen content (7–21 vol.%). Fresh, used, and regenerated catalysts were characterized by different methods to understand the correlation between regeneration conditions, coke content, and catalyst performance. The minor residual coke over the regenerated catalyst comprised active hydrocarbon pool intermediates (like naphthalene, benzaldehyde, phenol, and derivatives), which increased by decreasing regeneration temperature and promoted the selectivity to light olefins at earlier reaction times. The restored microporosity and lifetime of regenerated catalyst were superior by increasing temperature. However, higher attrition at 650 °C, as confirmed by SEM images, caused a partial weight loss of the catalyst and a slight decline in relative crystallinity, hence 600 °C was preferred with additional advantage of less energy consumption. Meanwhile, introducing lower oxygen not only moderated the coke oxidation rate but also enhanced the recovery of beneficial catalytic features for the MTO conversion. Consequently, considering an excellent regeneration as well as lower emission of CO2 detected in the flue gas, diluted air containing 14 vol.% O2 at 600 °C was suggested as the most promising method.

In-Situ Grown Nanohydroxyapatite on Graphene Oxide Nanoscrolls for Modulated Physicochemical Properties of Poly (Caprolactone) Composites

Polymer composites with exceptional bioactivity and controlled in vitro degradation are crucial in tissue engineering. A promising approach involves combining graphene oxide nanoscrolls (GONSs) and nanohydroxyapatite (nHA) with polycaprolactone (PCL). The synergy of these components enables the mineralization of nHA within GONSs through a two-step process: first, oxygen-containing anionic groups in the GONSs anchor Ca2+ ions, followed by the formation of dispersed nHA through chelation with CaHPO42− via electrovalent bonding. A thermal analysis of the scaffolds’ morphology and microstructure was conducted via DSC and SEM imaging. Its enhanced physical properties are attributed to interactions between PCL and nHA–GONSs, as confirmed by an FTIR analysis showing strong interfacial bonding. Enzymatic degradation studies demonstrated reduced weight loss in PCL–nHA–GONS composites over 21 days, highlighting GONSs’ role in enhancing dimensional stability and reinforcement. An EDS analysis post-degradation revealed increased Ca2+ deposition on scaffolds with nHA–GONSs, indicating improved biopolymer–bioceramic interaction facilitated by the GONSs’ scrolled structure. This research offers a straightforward yet effective method for functionalizing GONSs with biologically beneficial nHA, potentially advancing graphene-based biomaterial development.

Structural, vibrational and optical characterisations of Li2Ba3(P2O7)2:Cr3+ by solid-state reaction method

ABSTRACT Cr3+ doped Li2Ba3(P2O7)2 pyrophosphate nanopowder was successfully synthesised by solid-state reaction technique. The nanopowder was characterised by several techniques. X-ray diffraction analysis reveals orthorhombic crystal structureand average crystallite size values 34.21 and 28.41 nm are determined by Debye Scherrer’s formula and Williamson-Hall (W-H) method. The morphology displayed both SEM and HR-TEM images are irregular stone-like shapes. EDS analysis confirms the constituted elements. The SAED patterns of HR-TEM with well matched with XRD data. FT-IR and Raman spectra analysis confirmed incorporation of Cr3+ in the Li2Ba3(P2O7)2 pyrophosphate nanopowder. The EPR spectrum exhibited signal at g = 1.968 which is attributed to interaction between Cr3+ and Cr3+ exchange pair. The site symmetry of Cr3+ ions occupy a distorted octahedral. Photoluminescence spectrum exhibited bands correspond to ultraviolet, blue and green regions. The evaluated CCT of 6517 K indicates yellowish-green emission near cold light which reveals that the present prepared sample is useful for LEDs applications.

Distribution of Recent Benthic Foraminifera from the Outer Channel in and Around Gabakund Sea Mouth of Chilika Lagoon

Chilika (19°28’ to 19°54’ N; 85°54’N to 85°38’ E) lagoon situated in the east coast of India is considered to be one of the largest tropical coastal brackish water bodies in Asia. The unique setup of 60 km long narrow strip of sand barriers and swampy islands separating the area from the sea with few mouths of interconnections in the east and draining of tributaries of the river Mahanadi in the west while its environmental condition governed by tidal inflows and the southwest monsoon.The study of features of benthic foraminiferal tests, morphology, and abundance shed light upon paleoclimatic changes like monsoon variability, salinity, temperature, etc. Ten sediment samples were collected from the outer channel of Chilika lagoon in and around the Gabakund area and processed for species level study and SEM imaging following standard procedures. Sand dominates as the substrate towards the mouth at Gabakund area and silty to clayey sand towards the southern part of the Outer Channel. A total of 13 genera of benthic foraminifera belonging to 36 species were documented at the sampling stations. In the current study the species diversity and richness on the basis of the physico-chemical attributes of sea and river water incursion during pre-monsoon time in the outer channel of the lagoon is reported. In this region calcareous benthic foraminiferal are dominant while few agglutinated foraminifera have found their unusual niche.