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Enhancement of thermoelectric efficiency in vapor deposited Sb2Te3 and Sb1.8In0.2Te3 crystals
Crystal Research & Technology, Vol-49 (4), pp. 212-219. ISSN-0232-1300 -
Enhancement of thermoelectric efficiency in vapor deposited Sb 2Te3 and Sb1.8In0.2Te3 crystals
Pure and indium doped antimony telluride (Sb2Te3) crystals find applications in high performance room temperature thermoelectric devices. Owing to the meagre physical properties exhibited on the cleavage faces of melt grown samples, an attempt was made to explore the thermoelectric parameters of p-type crystals grown by the physical vapor deposition (PVD) method. The crystal structure of the grown platelets (9 mm8 mm2 mm) was identified as rhombohedral by x-ray powder diffraction method. The energy dispersive analysis confirmed the elemental composition of the crystals. The electron microscopic and scanning probe image studies revealed that the crystals were grown by layer growth mechanism with low surface roughness. At room temperature (300 K), the values of Seebeck coefficient S (c) and power factor were observed to be higher for Sb1.8In0.2Te 3 crystals (155 ?VK-1, 2.669 10-3 W/mK2) than those of pure ones. Upon doping, the thermal conductivity ? (c) was decreased by 37.14% and thus thermoelectric efficiency was improved. The increased figure of merit, Z = 1.23 10-3 K -1 for vapour grown Sb1.8In0.2Te3 platelets indicates that it could be used as a potential thermoelectric candidate. Pure and indium doped antimony telluride (Sb2Te 3) crystals were grown by the physical vapor deposition (PVD) method. Incorporation of indium atoms into the antimony sub lattice improved Seebeck coefficient and reduced thermal conductivity. The increased figure of merit, Z = 1.23 10-3K-1 for vapor grown Sb 1.8In0.2Te3 platelets indicates that it could be used as a potential thermoelectric candidate. 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. -
Enhancement of the thermal conductivity of a near room temperature magnetocaloric composite using graphene-like hybrid nanosheets derived from organic waste
Polymer matrix composites, fabricated to counter the inherent brittleness of magnetocaloric Heusler alloys, suffer from low thermal conductivity. Here, we demonstrate a low-cost, scalable route towards developing thermally conductive, mechanically robust near-room-temperature magnetocaloric composites by incorporating graphene-like hybrid nanostructures chemically synthesized from discarded sugarcane. Micron-sized particles obtained by manually grinding Ni50.2Mn36.7Sn13 ribbons possessing a strong magnetostructural transformation near room-temperature were chosen as the active magnetocaloric fillers. Both the functional fillers were incorporated into a polysulfone matrix by solution casting. Large values of isothermal entropy change ? 0.43 and -0.46 J/kg.K were observed for a ?H = 2T, driven by two successive first and second-order transformations within the alloy fillers. Additionally, an enhanced value of the in-plane thermal conductivity ? 3.06 0.4 W/m.K was observed in the composites owing to the formation of efficient thermal bridges/pathways by the graphene-like hybrid nanostructures, rendering them promising candidates for magnetic refrigeration applications. 2023 Acta Materialia Inc. -
Enhancement of the Electrochemical behaviour of Carbon Black via a defect induced approach
In order to address the rising global concern of energy storage, carbon-based materials have established themselves due to their distinct features. Despite the demand for the fabrication of supercapacitors from natural, inexpensive carbonaceous materials is on the rise, the intrinsic disorders present in such materials hinder their performance, and hence, tuning these defects can aid in the improvement of their electrochemical performance. In this study, carbon black is introduced with defects in the form of oxygen functional groups via oxidation and thermal exfoliation and the impact on its electrochemical performance is studied. Careful tuning of the type of oxygen functional moieties at the basal plane of the carbon lattice is observed to be the contributing factor for the electrochemical behaviour. The distortion in the graphitic lattice caused by the epoxy and hydroxyl groups alters the specific surface area, porosity, and thermal stability, facilitating easier ion diffusion rates and enhanced faradaic reactions. The obtained specific capacitance of the thermally exfoliated carbon black is as high as 246.49 Fg?1 in a three-electrode system and 82.85 F/g in a two-electrode setup, owing to an energy density of 5.63 Whkg?1 and a power density of 189.75 Wkg?1. It has also exhibited excellent cyclic stability and capacitance retention up to 4000 cycles. The equivalent series resistance is found to decrease from 5.67 to 4.96 ? making the material conductive. As a result, the electrochemical properties of carbon black can be enhanced by tuning the oxygen functional groups, making it a promising supercapacitive material. Graphical Abstract: (Figure presented.). Qatar University and Springer Nature Switzerland AG 2024. -
Enhancement of tensile strength and elastic modulus using bio-waste based carbon nanospheres doped polymer nanocomposites
The Carbon Nano Spheres (CNS) derived from areca nuts were synthesized from pyrolysis process and were used as fillers for fabrication of polymer nano composite materials. The filler materials are loaded in 0.05%, 0.1% and 0.5% loading percentages. The optimum sample was subjected to heat treatment. The tensile strength, elastic modulus and % of elongation were investigated for all samples. The Scanning Electron Microscope (SEM) images revealed the morphological features of optimum samples and hence the uniform dispersion of CNS in polymer matrix. The 0.1% samples showed 10% improvement in Ultimate Tensile Strength (UTS) and 24% improvement in Elastic modulus compared to bare epoxy material. When 0.1% samplewas subjected to heat treatment under 200C the UTS improved by 23%. Hence, CNS reinforced composite materials exhibited unique properties like high strength, less weight and low cost making them suitable for various structural applications such as aerospace, automotive, construction, and electronics industries. The Polymer Society, Taipei 2024. -
Enhancement of substitution voices using F1 formant deviation analysis and DTW based template matching
Speech is the best way to express the thoughts and feelings among the human beings. But for many reasons the sound produced by human beings becomes disordered voice and termed with many names based on the cause as stammering, dys-theria, apraxia and so on. In the above mentioned few examples, the voice becomes disordered because of the underperformance of body's organ. The larynx is removed in some human beings because of cancer. For them an artificial larynx transducer (ALT) is used to produce the sounds. The above all sounds are categorized as disordered voice and the sound produced by ALT is also called as Substitution voice. In this paper, a method is used to improve the quality of substitution voice produced by ALT. Algorithm is developed to estimate undesired audio components from the device output and remove the same using Non Linear Spectral Subtraction (NLSS) technique. Further, Fundamental (F0) contour and novel parameter F1 formant deviation of healthy speech (HE) and ALT speech are determined. The above two parameters are estimated and stored during the training phase of the system. In the test phase, the above mentioned parameters are estimated and they are used to scale down the database to reduce overall enhancement time. Next step is template matching done by mapping test data with training data using Dynamic Time Warping (DTW) Technique. The data base with least distance estimation is recognized as the utterance and the same is played back. 2017 IEEE. -
Enhancement of resilience an quality of life using strength based counselling and the mediating role of parental bonding in adolescents with type 1 diabetes
The current study was an attempt to understand the socio-demographic profile of newlineadolescents with type 1diabetes, the relationship between variables such as resilience, quality of life, parental bonding and the mediating role of parental bonding. It was also aimed to understand parent s perception of the adolescent s resilience and quality of life and their newlineexperiences. In phase 1, 100 adolescents/ newlinechildren (M=40, F=60, Age 10-18years) with an newlineexisting diagnosis of type 1 diabetes and their parents were enrolled from two hospitals and one clinic in Bangalore. The adolescents were administered Paediatric Quality Of Life for Diabetics (PedsQL) (Child and Adolescent Form), The Resilience Scale for Youth (CYRM), The Parental Bonding Instrument PBI (Father and Mother Form ). Parents were administered the consent form, demographic data sheet and parent version of resilience and quality of life.All scales were translated and back translated. In Phase 2 of the study, an intervention model based on the principles of strength newlinebased counselling to enhance resilience and quality of life (SBCTD1) was developed and newlineused. Qualitative interviews were conducted to understand the experiences of parents of newlinechildren/adolescents having type 1 diabetes. These interviews were tape recorded. 50 newlineadolescents from Phase1, were randomly assigned to the intervention group (n=25) and the control group (n=25). For the intervention group after going through the sessions the Resilience Scales and The Paediatric Quality of Life scales were administered after one and three months respectively. HbA1c values were also collected again after three months of newlineintervention. Control group received regular care and treatment at the center and were not newlineexposed to the model developed for the study. -
Enhancement of Reflected Faces on Semi-reflecting Surfaces
Face recognition is interesting research area in computer vision. This paper proposes to enhance faces reflected on semi reflecting surfaces such as glass window, glass screens or any other mirror like surfaces. Visibility or clarity of reflected image is depending on the reflecting ability of material surface on which reflection occurs. Other than mirror surfaces, majority of reflected images are less visibility. So recognition of reflected face is a challenge in the proposed method. This paper addresses enhancement of reflected face image. Estimating atmospheric light and medium transmission map, recover haze free image. Apply CLAHE i.e., adaptive histogram equalization by limiting contrast to obtain enhanced reflected face image. 2019 IEEE. -
Enhancement of Phenolic and Polyacetylene Production in Chinese Lobelia (Lobelia chinensis Lour.) Plant Suspension Culture by Employing Silver, Iron Oxide Nanoparticles and Multiwalled Carbon Nanotubes as Elicitors
Silver nanoparticles (AgNPs), iron oxide nanoparticles (Fe2O4NPs), and multiwalled carbon nanotubes (MWCNTs) are widely used in various applications, such as biomedicine, environmental remediation, and agriculture. In addition, these nanomaterials can affect the production of bioactive compounds in plants that have pharmacological activities. In the current study, the in vitro plant cultures of Chinese lobelia (Lobelia chinensis Lour.) were established in MS medium and treated with 0, 12.5, 25, 37.5, and 50 mg L?1 AgNPs or Fe2O4NPs, or MWCNTs. Initially, plants were grown for four weeks without any elicitors, and after that, the cultures were treated with nano-elicitors for one week. After five weeks, the effects of nano-elicitors were estimated on growth, total phenolic, flavonoids, polyacetylenes, and ABTS/DPPH/FRAP antioxidant activity was investigated. The results showed that lower levels of AgNPs (25 mg L?1), Fe2O4NPs (25 mg L?1), and MWCNTs (12.5 mg L?1) favored the accumulation of fresh and dry biomass. Whereas, 37.5 mg L?1 AgNPs, 25 mg L?1 Fe2O4NPs, and 37.5 mg L?1 MWCNTs enhanced the accumulation of total phenolics, flavonoids, specific phenolic compounds including chlorogenic acid, catechin, phloretic acid, coumaric acid, salicylic acid, naringin, myricetin, linarin, and polyacetylenes viz. lobetylonin and lobetyolin in higher concentrations. The plant extracts elicited by nanomaterials also depicted very good antioxidant activities according to ABTS, DPPH, and FRAP assays. These results suggest that specific nanomaterials, and at specific levels, could be used for the production of bioactive compounds from shoot cultures of Chinese lobelia. 2025 by the authors. -
Enhancement of Phenolic and Polyacetylene Accumulation in Lobelia chinensis (Chinese lobelia) Plantlet Cultures Through Yeast Extract and Salicylic Acid Elicitation
Lobelia chinensis (Lour.) is a medicinal plant that contains phytochemicals, such as phenolics and polyacetylene compounds, with beneficial biological activities. In vitro cultures are typically employed for biomass generation and plant multiplication. However, the current biotechnological approaches for producing these chemicals are ineffective, which is why bioelicitors are being used to boost synthesis of these molecules. Plantlet cultures were established in vitro using Murashige and Skoog medium supplemented with 3% sucrose (w/v). Following 4 weeks of culture initiation, the plantlet cultures were treated with 0, 25, 50, 100, or 200 mg L?1 of yeast extract (YE) or with 0, 25, 50, 100, or 200 M of salicylic acid (SA) for 1 week to boost the synthesis of bioactive compounds. The amounts of total phenolics, total flavonoids, specific phenolics including catechin, phloretic acid, linarin, and polyacetylenes, including lobetyolinin and lobetylin, were considerably elevated in the plantlet cultures treated with 50 mg L?1 YE and/or 25 M SA. The 2,2 Diphenyl 1 picrylhydrazyl (DPPH) radical scavenging assay, 2,2?-azino-bis (3-ethybenzothiazoline-6-sulphonic acid) (ABTS) assay, and ferric reducing antioxidant power (FRAP) assay were performed to assess the antioxidant properties of the plantlets. The elicitor-treated plantlets were found to have higher antioxidant activity. Thus, plantlet biomass produced in vitro can be used as a raw material to produce medicinal and nutraceutical products. 2025 by the authors. -
Enhancement of nitrogen assimilation and photosynthetic efficiency by novel iron pulsing technique in Oryza sativa L. var Pankaj
Rice is a major food crop. Due to urbanization and climate change, rice production is declining, posing a threat to the increasing food demand. For this, a modified technique of priming is used to enhance plant vigor. In the present study an endogenous rice cultivar was treated with two different iron salts for 72 h and grown for 14 days in nutrient solution. This increased the iron content of the samples which further escalated the photosynthetic efficiency and carbon assimilation in the treated plants. Photosynthesis being correlated to nitrogen assimilation, nitrogen assimilation intermediates and protein content were also elevated in treated plants. Plants showed no symptoms of stress as evident from low malondialdehyde content and increased antioxidant enzymes activity. From this study it can be inferred that, treatment with iron during germination, helps to trigger growth by facilitating photosynthesis and nitrogen assimilation. 2019 Elsevier Masson SAS -
Enhancement of mechanical properties of epoxy/halloysite nanotube (HNT) nanocomposites
The particulate filled epoxy composites show lower mechanical properties than neat composites due to lack strength of uniform dispersion of particles leading to poor in interfacial strength between matrix and fillers. In this study, ultrasonification dispersion technique is employed to achieve a homogenous dispersion of halloysite nanotubes (HNTs) in epoxy resin. The nanocomposites are fabricated by solution casting method and specimens are prepared as per ASTM standards. The various test has been conducted as per ASTM procedure to evaluate the mechanical properties viz. density, hardness, tensile, flexural, ILSS and impact strength of the nanocomposites consisting of different weight (wt)% of HNTs varying in the range of 04 with the interval of 1. As per the experimental investigation, the selected dispersion techniques enhances the mechanical properties of the nanocomposite by the loading of HNT. Further, the study revealed that the 3wt% of HNT with ultrasonic homogenized nanocomposite shows superior mechanical strength as compared to other nanocomposites. Hence it is evident that the properties of the nanocomposite depends on the quantity of filler present and dispersion condition. The dispersion condition and fractured surfaces are analyzed through the SEM micrographs. 2019, Springer Nature Switzerland AG. -
Enhancement of Image Classification Using Transfer Learning and GAN-Based Synthetic Data Augmentation
Plastic bottle recycling has a crucial role in environmental degradation and protection. Position and background should be the same to classify plastic bottles on a conveyor belt. The manual detection of plastic bottles is time consuming and leads to human error. Hence, the automatic classification of plastic bottles using deep learning techniques can assist with the more accurate results and reduce cost. To achieve a considerably good result using the DL model, we need a large volume of data to train. We propose a GAN-based model to generate synthetic images similar to the original. To improve the image synthesis quality with less training time and decrease the chances of mode collapse, we propose a modified lightweight-GAN model, which consists of a generator and a discriminator with an auto-encoding feature to capture essential parts of the input image and to encourage the generator to produce a wide range of real data. Then a newly designed weighted average ensemble model based on two pre-trained models, inceptionV3 and xception, to classify transparent plastic bottles obtains an improved classification accuracy of 99.06%. 2022 by the authors. Licensee MDPI, Basel, Switzerland. -
Enhancement of free convection from horizontal-base straight-fin heat sink by partial shrouding
This work presents a simple method to improve natural convection heat transfer performance of horizontal-base straight-fin heat sink by adding partial shroud plates on top of the heat sink at both ends. Experiments are conducted in conjunction with a detailed three-dimensional (3D) computational study. The numerical model is validated using experimental results. With partial shrouding, the modification and effective utilization of airflow surrounding the heat sink leads to significant heat transfer enhancement. The installation of shroud plates effectively improves the mass flowrate of air admitted into the fin channel. Further, the airflow drawn above the heat sink dissipates heat from the upper surface of the shroud plate. There is also a significant heat dissipation from the lower surface of the shroud plate which is exposed to cold air drawn from the side-end of the heat sink. The heat transfer from the existing optimal conventional heat sink is improved by 17% with the introduction of shroud plates. An optimal width of the shroud plate is identified to exist for the maximum heat transfer. The percentage enhancement in heat transfer achieved by partial shrouding increases with a decrease in the fin height and with an increase in the fin spacing. The proposed compact heat sink design would be of application in enhancing passive heat dissipation from light-emitting diode (LED) lights and other electronic devices, especially when size constraints exist. Copyright 2020 by ASME -
Enhancement of efficiency of military cloud computing using lanchester model
Cloud computing is a technology that uses centrally processed computing resources over the Internet by a large number of users. Because many requests are concentrated on cloud servers, they must be properly distributed to avoid degradation of quality. Load balancing categorizes requests from users according to established algorithms and assigns appropriate virtual machines. Because load balancing algorithms are developed according to the cloud's usage environment, various algorithms are being utilized. Recently, government agencies are also interested in introducing cloud technologies beyond private sectors. Many militaries have selected Cloud as its basic task to apply new technologies such as AI to military operations. However, there is no precedent for military cloud development, and the lack of doud technology research considering the operational environment has delayed the progress of cloud adoption. The algorithm presented by this paper makes the combat power, which varies according to the importance of the operation, an important variable. This variable makes each user's access to computing resources different. Although similar to other dynamic algorithms, the impact of priorities is so big that the degree of imbalance between tasks was higher. 2020 IEEE. -
Enhancement of coal nanostructure and investigation of its novel properties
Coal is a mineral and is extensively used as a solid fuel in developing nations and has a sizeable share in the global fossil fuel reserve. Utilization of this resource generates excess spoil and large volume of low grade waste to the environment. In recent years there have been serious research on enhancing its value and exploring the utility of this carbonaceous material to novel carbon materials. The Minerals, Metals & Materials Society 2018. -
Enhancement of Agriculture Feeder Performance by Optimal Sizing and Placing of Solar PV Tree through AEO-Based Optimization Technique
Electrical demand, which makes up a large share of the overall power market, agriculture at the top of the list of priorities. To provide end users with a dependable and high-quality supply via various feeders and renewable energy sources, distribution generations are now being developed. In recent years, solar PV systems have been used to meet the demands of numerous applications, including boosting the efficiency of distribution networks. This paper presents the system with effect ive optimization method like Artificial Eco-System based Optimization Technique for identification of the best location to install distribution generation and the optimum size to minimize feeder losses. To meet service expectations, the integration of a solar PV system is swapped out for a solar tree in this suggested work. A 28-bus Indian agriculture feeder is considered for better understanding the proposed algorithm. MATLAB software is used for implementing the proposed optimization technique and CREO-2.0 is used for designing the 3-dimensional solar PV tree. 2023 by the Kamal Kumar U and Varaprasad Janamala. -
Enhancement of Accuracy Level in Parking Space Identification by using Machine Learning Algorithms
Parking space identification is a crucial component in the development of intelligent transportation systems and smart cities. Accurate detection of parking spaces in urban areas can significantly improve traffic management, reduce congestion, and enhance overall parking efficiency. This proposed model is focuses on enhancing the accuracy of parking space identification through the utilization of Support Vector Machine (SVM) algorithms. The proposed methodology involves the following steps. First, a dataset comprising labelled parking space images is collected and pre-processed to ensure optimal quality and consistency. Next, feature extraction techniques are applied to capture certain relevant spatial and textural information from the images in the dataset, enabling the creation of informative feature vectors. These feature vectors are then utilized to train a SVM model, which is well-known for its capability to handle complex classification tasks. To measure the effectiveness of the SVM-based approach, a comprehensive set of experiments is carried out using real-world parking data. The performance metrics is to analysis accuracy level of the parking space identification. Comparative analysis has been done by comparing the proposed SVM approach with other popular machine learning algorithmsto demonstrate the superiority. The results indicate that the SVM-based model achieves a significantly higher accuracy level in parking space identification compared to other existing algorithms. 2023 IEEE. -
Enhancement in air-cooling of lithium-ion battery packs using tapered airflow duct
Temperature uniformity and peak-temperature reduction of lithium-ion battery packs are critical for adequate battery performance, cycle life, and safety. In air-cooled battery packs that use conventional rectangular ducts for airflow, the insufficient cooling of cells near the duct outlet leads to temperature nonuniformity and a rise in peak temperature. This study proposes a simple method of using a converging, tapered airflow duct to attain temperature uniformity and reduce peak temperature in air-cooled lithium-ion battery packs. The conjugate forced convection heat transfer from the battery pack was investigated using computational fluid dynamics, and the computational model was validated using experimental results for a limiting case. The proposed converging taper provided to the airflow duct reduced the peak temperature rise and improved the temperature uniformity of the batteries. For the conventional duct, the boundary layer development and the increase in air temperature downstream resulted in hotspots on cells near the outlet. In contrast, for the proposed tapered duct, the flow velocity increased downstream, resulting in improved heat dissipation from the cells near the outlet. Furthermore, the study investigated the effects of taper angle, inlet velocity, and heat generation rate on the flow and thermal fields. Notably, with the increase in taper angle, owing to the increase in turbulent heat transfer near the exit, the location of peak temperature shifted from the exit region to the central region of the battery pack. The taper-induced improvement in cooling was evident over the entire range of inlet velocities and heat generation rates investigated in the study. The peak temperature rise and maximum temperature difference of the battery pack were reduced by up to 20% and 19%, respectively. The proposed method, being effective and simple, could find its application in the cooling arrangements for battery packs in electric vehicles. 2023 Y?ld?z Technical University. This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/). All Rights Reserved. -
Enhanced Wavelet Block Shrinkage Technique For Mammogram Denoising Using K-Means Clustering And Neural Networks
The proposed research study introduces a novel approach for denoising digital mammograms by improving the existing wavelet block shrinkage filtering method with K-Means clustering and a convolutional neural network. This approach involves decomposing both the original and noisy mammograms into frequency subbands using 2D discrete wavelet transformation. The resulting subbands are then grouped into multiple clusters based on similar features of the wavelet coefficients, employing K-Means clustering. This represents an improvement over the traditional block shrinkage method, which uses fixed-size blocks. These clusters from the original and noisy mammograms are paired to train a convolutional neural network, which serves as an optimal shrinkage function. This neural network-based thresholding mechanism replaces traditional hard and soft thresholding methods that rely on a universal threshold. Test results demonstrate that the proposed enhanced wavelet block shrinkage mechanism achieves a 20% improvement in peak signal-to-noise ratio and a 5% increase in structural similarity index score compared to traditional wavelet block shrinkage. Authors.