Search results for: high temperature polymer electrolyte membrane fuel cell

Authors: Deokyeong Choe, Sung Hun Youn, Younggon Kim, Chul Soo Shin

Abstract:

L-Cysteine is extensively used as a supplement of pharmaceuticals, cosmetics, food and feed additives. It has obtained industrially by hydrolysis of human hair and poultry feathers. However, there are some problems such as the restriction of using materials from animals and the intractable waste pollution. The enzymatic conversion has been regarded as an environmental-friendly method. Currently, the biggest bottle-neck of enzymatic conversion is the low yield of L-cysteine due to the low substrate solubility. In this study, the method of enhancing the solubility of the substrate D,L-2-amino-Δ2-thiazoline-4-carboxylicacid (ATC) was developed and the enzymatic reaction at high concentration levels was performed. A large amount of substrate in aqueous solutions was dissolved by pH control using salts. As the pH of the solution increased, the solubility of ATC increased. It was thought that a shift of ATC from acid form (-COOH) to dissociated carboxylic group (-COO-) would improve its hydrophilicity leading to solubility increase. The highest solubility of ATC was 610 mM at pH 10.5, whereas the maximum reaction rate was obtained at pH 8.3. As a result, a high L-cysteine yield of 250 mM was achieved at pH 9.1, which was obtained from a combination of optimum pH conditions for ATC solubility and enzymatic conversion. This yield corresponds to approximately 18 times of that in previous reports.

Keywords: D, L-2-amino-Δ2-thiazoline-4-carboxylicacid, enzymatic conversion, high-substrate solubilization, L-Cysteine

Procedia PDF Downloads 416

Authors: Tolga Arda Eraslan

Abstract:

The quality of the indoor environment is significant to occupants’ health, comfort, and productivity, as Covid-19 spread throughout the world, people started spending most of their time indoors. Since buildings are getting bigger, mechanical ventilation systems are widely used where natural ventilation is insufficient. Four primary tasks of a ventilation system have been identified indoor air quality, comfort, contamination control, and energy performance. To fulfill such requirements, air diffusers, which are a part of the ventilation system, have begun to enter our lives in different airflow distribution systems. Detailed observations are needed to assure that such devices provide high levels of comfort effectiveness and energy efficiency. This study addresses these needs. The objective of this article is to observe air characterizations of different air diffusers at different angles and their effect on people by the thermal comfort model in CFD simulation and to validate the outputs with the help of data results based on a simulated office room. Office room created to provide validation; Equipped with many thermal sensors, including head height, tabletop, and foot level. In addition, CFD simulations were carried out by measuring the temperature and velocity of the air coming out of the supply diffuser. The results considering the flow interaction between diffusers and surroundings showed good visual illustration.

Keywords: computational fluid dynamics, fanger’s model, predicted mean vote, thermal comfort

Procedia PDF Downloads 99

Authors: Yutong An

Abstract:

Premature babies in the Neonatal Intensive Care Unit (NICU) are usually protected in individual incubators to ensure a constant temperature and humidity. Accompanied by 24-hour monitoring by medical equipment, this provides a considerable degree of protection for the growth of preterm babies. However, preterm babies are still continuously exposed to noise at excessively high decibels (>45dB). Such noise has a highly damaging effect on the growth and development of preterm babies. For example, in the short term, it can lead to sleep deprivation, stress reactions, and difficulty calming emotions, while in the long term, it can trigger endocrine disorders, metabolic disorders, and hearing impairment. Fortunately, musical interventions in the NICU have been shown to provide calmness to newborns. This article integrates existing research on three types of music that are beneficial for preterm infants and their respective advantages and disadvantages. This paper aims to present a possibility, based on existing NICU equipment and experimental data related to musical interventions, to reduce the impact of noise on preterm babies in the NICU through a system design approach that incorporates a personalized adjustable music system in the incubator and an overall music enhancement in the open bay of the NICU.

Keywords: music interventions, neonatal intensive care unit (NICU), premature babies, neonatal nursing

Procedia PDF Downloads 49

Authors: Alireza Monzavi Chaleshtari, Mahnaz Aliakbari Dehkordi, Mina Gholampour, Majid Saffarinia, Tayebeh Mohtashami, Amin Asadi Hieh

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The study aimed to assess the impact of positive psychology education on the social well-being of high school girls experiencing premenstrual syndrome (PMS). The statistical population comprised high school girls with PMS, with 30 randomly selected participants divided into two groups: 15 in the experimental group and 15 in the control group. The research employed a pre-test and post-test design using a standard questionnaire to evaluate premenstrual syndrome symptoms over a 7-day period before menstruation to a maximum of 2 days after menstruation, along with the Social Keys welfare questionnaire. During the study, the experimental group underwent an 8-session positive psychology group program. Data analysis was conducted using analysis of covariance. The results indicated a significant positive effect of positive psychology training on enhancing the social well-being of girls (p < 0.05). In conclusion, the findings suggest that positive psychology interventions can effectively increase social well-being among high school girls experiencing premenstrual syndrome.

Keywords: positive psychology, premenstrual syndrome, social welfare, girls

Procedia PDF Downloads 86

Authors: H. Shokouhmand, A. Ghanami

Abstract:

Heat pipe is simple heat transfer device which combines the conduction and phase change phenomena to control the heat transfer without any need for external power source. At hot surface of heat pipe, the liquid phase absorbs heat and changes to vapor phase. The vapor phase flows to condenser region and with the loss of heat changes to liquid phase. Due to gravitational force the liquid phase flows to evaporator section.In HVAC systems the working fluid is chosen based on the operating temperature. The heat pipe has significant capability to reduce the humidity in HVAC systems. Each HVAC system which uses heater, humidifier or dryer is a suitable nominate for the utilization of heat pipes. Generally heat pipes have three main sections: condenser, adiabatic region and evaporator.Performance investigation and optimization of heat pipes operation in order to increase their efficiency is crucial. In present article, a parametric study is performed to improve the heat pipe performance. Therefore, the heat capacity of heat pipe with respect to geometrical and confining parameters is investigated. For the better observation of heat pipe operation in HVAC systems, a CFD simulation in Eulerian- Eulerian multiphase approach is also performed. The results show that heat pipe heat transfer capacity is higher for water as working fluid with the operating temperature of 340 K. It is also observed that the vertical orientation of heat pipe enhances it’s heat transfer capacity.

Keywords: heat pipe, HVAC system, grooved heat pipe, heat pipe limits

Procedia PDF Downloads 358

Authors: H. Shokouhmand, A. Ghanami

Abstract:

Heat pipe is a simple heat transfer device which combines the conduction and phase change phenomena to control the heat transfer without any need for external power source. At hot surface of the heat pipe, the liquid phase absorbs heat and changes to vapor phase. The vapor phase flows to condenser region and with the loss of heat changes to liquid phase. Due to gravitational force, the liquid phase flows to evaporator section. In HVAC systems, the working fluid is chosen based on the operating temperature. The heat pipe has significant capability to reduce the humidity in HVAC systems. Each HVAC system which uses heater, humidifier or dryer is a suitable nominate for the utilization of heat pipes. Generally, heat pipes have three main sections: condenser, adiabatic region, and evaporator.Performance investigation and optimization of heat pipes operation in order to increase their efficiency is crucial. In the present article, a parametric study is performed to improve the heat pipe performance. Therefore, the heat capacity of the heat pipe with respect to geometrical and confining parameters is investigated. For the better observation of heat pipe operation in HVAC systems, a CFD simulation in Eulerian- Eulerian multiphase approach is also performed. The results show that heat pipe heat transfer capacity is higher for water as working fluid with the operating temperature of 340 K. It is also showed that the vertical orientation of heat pipe enhances its heat transfer capacity.

Keywords: heat pipe, HVAC system, grooved heat pipe, CFD simulation

Procedia PDF Downloads 480

Authors: M. Heydari, A. Ghanami

Abstract:

Heat pipe is simple heat transfer device which combines the conduction and phase change phenomena to control the heat transfer without any need for external power source. At hot surface of heat pipe, the liquid phase absorbs heat and changes to vapor phase. The vapor phase flows to condenser region and with the loss of heat changes to liquid phase. Due to gravitational force the liquid phase flows to evaporator section.In HVAC systems the working fluid is chosen based on the operating temperature. The heat pipe has significant capability to reduce the humidity in HVAC systems. Each HVAC system which uses heater, humidifier or dryer is a suitable nominate for the utilization of heat pipes. Generally heat pipes have three main sections: condenser, adiabatic region and evaporator.Performance investigation and optimization of heat pipes operation in order to increase their efficiency is crucial. In present article, a parametric study is performed to improve the heat pipe performance. Therefore, the heat capacity of heat pipe with respect to geometrical and confining parameters is investigated. For the better observation of heat pipe operation in HVAC systems, a CFD simulation in Eulerian- Eulerian multiphase approach is also performed. The results show that heat pipe heat transfer capacity is higher for water as working fluid with the operating temperature of 340 K. It is also showed that the vertical orientation of heat pipe enhances it’s heat transfer capacity.

Keywords: heat pipe, HVAC system, grooved heat pipe, heat pipe limits

Procedia PDF Downloads 431

Authors: Phuong Nguyen

Abstract:

Along with the ongoing energy transition, the electrical power system is getting more vulnerable with the increasing penetration of renewable energy sources (RES). By replacing a large amount of fossil fuel-based power plants with RES, the rotating mass of the power grid is decreasing drastically, which has been reported by a number of system operators. This leads to a huge challenge for operators to secure the operation of their grids in all-time horizon ranges, from sub-seconds to minutes and even hours. There is a need to revise the grid capabilities in dealing with transient (angle) stability and voltage dynamics. While the traditional approaches relied on deterministic scenarios (worst-case scenarios), there is also a need to cover a whole range of probabilities regarding a wide range of uncertainties coming from massive RES units. To contribute to handle these issues, this paper aims to focus on developing a new analytical approach for transient stability.

Keywords: transient stability, uncertainties, renewable energy sources, analytical approach

Procedia PDF Downloads 57

Authors: D. Densenbal, Ts. Naidansuren, M. Oyunchimeg, Ts. Manaljav, D. Udval, L. Khosbayar, Kh. Solongo, D. Ichinnorov, B. Solongo

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Background: The rapid economic growth and to the common use of smoky fuel such as coal in the small traditional houses (Ger) in Mongolia is worsening its air pollution problem. In addition, the smoking rate is considered to be high. Despite these conditions, few prevalence studies of COPD epidemiology and diagnose have been performed in Mongolia. The spirometric test is a widely used diagnose for COPD. Aims: Healthy and over the 40 aged adults were evaluated of Pulmonary function test in Ulaanbaatar. Methods: Healthy, over the 40 aged residences were admitted for this study from II sub-district, in Khan-Uul district of Ulaanbaatar city. In this cross-sectional study. Health information was collected 184 subjects between 01-03 July in 2013; spirometry device was named Hichest–105 Japan that was employed for this study. Studies were using the acceptability standards outlined, and data were compared with personal reference data generated on Asian subjects which were performed abnormally to evaluated by global initiative obstructive lung decreases (GOLD). Data were analyzed using SPSS 20 software. Results: A total of 134 subjects (age 52.9±9.8, man 32.8%) were performed PFT which were interpreted normal 73.9% (sum of man 65.0% and woman 79.4% ), abnormal 26.1% which were typed obstruction 17.2% (23), restriction 6% (8), mixed 3% (4). Airflow obstruction were determined in all man 25% (11), woman 13.3% (12) which were classified mild 43.4% (man 54.5%, woman 33.3%), moderate 52.2% (36.3% vs. 66.7%) and severe 4.3% man 1 GOLD degree. Undetermined a very severe obstruction. Normal PFT subjects were compared a group of gender and age group which man was significantly higher than the women (p<0.05). Age group of PFT decrease was no difference in gender (p>0.05) also no difference in BMI (p>0.05). Normal PFT subjects were compared with predicted values were used to Asian population which was significantly lower than FEV1 (0.15±0.36 l), PEF (1.92±1.31 l) and same deference occurred man (FEV1 0.19±0.42 l, PEF 2.04±1.64), women (0.14±0.33 l vs. 1.86±1.15 l). The decrease of FEV1 was defined in over the 60 age group higher than other age groups. Conclusion: Not only observed an air flow limitation prevalence dominance in all case but also COPD prevalence diagnosed man were higher than women. Normal PFT subjects were compared with predicted values were used to Asian population which was significant air flow limitation started early.

Keywords: PFT, obstruction, FEV1, COPD

Procedia PDF Downloads 201

Authors: G. Kim, R. Sterkenburg

Abstract:

One of the disadvantages of honeycomb sandwich structure is that they are prone to fluid intrusion. The purpose of this study is to determine if the structural properties of honeycomb core are affected by contact with a fluid. The test specimens were manufactured of fiberglass prepreg for the facesheets and Nomex^® honeycomb core for the core material in accordance with ASTM C-365/365M. Test specimens were soaked in several different kinds of fluids, such as aircraft fuel, turbine engine oil, hydraulic fluid, and water for a period of 60 days. A flatwise compressive test was performed, and the test results were analyzed to determine how the contact with aircraft fluids affected the compressive strength of the Nomex^® honeycomb core and how the strength was recovered when the specimens were dry. In addition, the investigation of de-bonding between facesheet and core material after soaking were performed to support the study.

Keywords: sandwich structure, honeycomb, environmental degradation, debonding

Procedia PDF Downloads 155

Authors: Karina I. Hidas, Csaba Németh, Anna Visy, Judit Csonka, László Friedrich, Ildikó Cs. Nyulas-Zeke

Abstract:

Egg yolk is a popular ingredient in the food industry due to its gelling, emulsifying, colouring, and coagulating properties. Because of the heat sensitivity of proteins, egg yolk can only be heat treated at low temperatures, so its shelf life, even with the addition of a preservative, is only a few weeks. Freezing can increase the shelf life of liquid egg yolk up to 1 year, but it undergoes gelling below -6 ° C, which is an irreversible phenomenon. The degree of gelation depends on the time and temperature of freezing and is influenced by the process of thawing. Therefore, in our experiment, we examined egg yolks thawed in different ways. In this study, unpasteurized, industrially broken, separated, and homogenized liquid egg yolk was used. Freshly produced samples were frozen in plastic containers at -18°C in a laboratory freezer. Frozen storage was performed for 90 days. Samples were analysed at day zero (unfrozen) and after frozen storage for 1, 7, 14, 30, 60 and 90 days. Samples were thawed in two ways (at 5°C for 24 hours and 30°C for 3 hours) before testing. Calorimetric properties were examined by differential scanning calorimetry, where heat flow curves were recorded. Denaturation enthalpy values were calculated by fitting a linear baseline, and denaturation temperature values were evaluated. Besides, dry matter content of samples was measured by the oven method with drying at 105°C to constant weight. For statistical analysis two-way ANOVA (α = 0.05) was employed, where thawing mode and freezing time were the fixed factors. Denaturation enthalpy values decreased from 1.1 to 0.47 at the end of the storage experiment, which represents a reduction of about 60%. The effect of freezing time was significant on these values, already the enthalpy of samples stored frozen for 1 day was significantly reduced. However, the mode of thawing did not significantly affect the denaturation enthalpy of the samples, and no interaction was seen between the two factors. The denaturation temperature and dry matter content did not change significantly either during the freezing period or during the defrosting mode. Results of our study show that slow freezing and frozen storage at -18°C greatly reduces the amount of protein that can be denatured in egg yolk, indicating that the proteins have been subjected to aggregation, denaturation or other protein conversions regardless of how they were thawed.

Keywords: denaturation enthalpy, differential scanning calorimetry, liquid egg yolk, slow freezing

Procedia PDF Downloads 113

Authors: Tibor Ajtai, Noémi Utry, Máté Pintér, Tomi Smausz, Zoltán Kónya, Béla Hopp, Gábor Szabó, Zoltán Bozóki

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Characterization of spectral responses of light absorbing carbonaceous particulate matter (LAC) is of great importance in both modelling its climate effect and interpreting remote sensing measurement data. The residential or domestic combustion of coal is one of the dominant LAC constituent. According to some related assessments the residential coal burning account for roughly half of anthropogenic BC emitted from fossil fuel burning. Despite of its significance in climate the comprehensive investigation of optical properties of residential coal aerosol is really limited in the literature. There are many reason of that starting from the difficulties associated with the controlled burning conditions of the fuel, through the lack of detailed supplementary proximate and ultimate chemical analysis enforced, the interpretation of the measured optical data, ending with many analytical and methodological difficulties regarding the in-situ measurement of coal aerosol spectral responses. Since the gas matrix of ambient can significantly mask the physicochemical characteristics of the generated coal aerosol the accurate and controlled generation of residential coal particulates is one of the most actual issues in this research area. Most of the laboratory imitation of residential coal combustion is simply based on coal burning in stove with ambient air support allowing one to measure only the apparent spectral feature of the particulates. However, the recently introduced methodology based on a laser ablation of solid coal target opens up novel possibilities to model the real combustion procedure under well controlled laboratory conditions and makes the investigation of the inherent optical properties also possible. Most of the methodology for spectral characterization of LAC is based on transmission measurement made of filter accumulated aerosol or deduced indirectly from parallel measurements of scattering and extinction coefficient using free floating sampling. In the former one the accuracy while in the latter one the sensitivity are liming the applicability of this approaches. Although the scientific community are at the common platform that aerosol-phase PhotoAcoustic Spectroscopy (PAS) is the only method for precise and accurate determination of light absorption by LAC, the PAS based instrumentation for spectral characterization of absorption has only been recently introduced. In this study, the investigation of the inherent, spectral features of laser generated and chemically characterized residential coal aerosols are demonstrated. The experimental set-up and its characteristic for residential coal aerosol generation are introduced here. The optical absorption and the scattering coefficients as well as their wavelength dependency are determined by our state-of-the-art multi wavelength PAS instrument (4λ-PAS) and multi wavelength cosinus sensor (Aurora 3000). The quantified wavelength dependency (AAE and SAE) are deduced from the measured data. Finally, some correlation between the proximate and ultimate chemical as well as the measured or deduced optical parameters are also revealed.

Keywords: absorption, scattering, residential coal, aerosol generation by laser ablation

Procedia PDF Downloads 348

Authors: Carlos F. Sanz-Navarro, Sonia Fereres

Abstract:

Binary and ternary mixtures of molten salts are excellent thermal energy storage systems and have been widely used in commercial tanks both in nuclear and solar thermal applications. However, the energy density of the commercially used mixtures is still insufficient, and therefore, new systems based on latent heat storage (or phase change materials, PCM) are currently being investigated. In order to shed some light on the macroscopic physical properties of the molten salt phases, knowledge of the microscopic structure and dynamics is required. Several molecular dynamics (MD) simulations have been performed to model the thermal behavior of (Li,K)2CO3 mixtures. Up to this date, this particular molten salt mixture has not been extensively studied but it is of fundamental interest for understanding the behavior of other commercial salts. Molten salt diffusivities, the internal electrical ion mobility, and the physical properties of the solid-liquid phase transition have been calculated and compared to available data from literature. The effect of anion polarization and the application of a strong external electric field have also been investigated. The influence of electrical ion mobility on local composition is explained through the Chemla effect, well known in electrochemistry. These results open a new way to design optimal high temperature energy storage materials.

Keywords: atomistic simulations, thermal storage, latent heat, molten salt, ion mobility

Procedia PDF Downloads 312

Authors: Ariadne C. Catto, Luis F. da Silva, Khalifa Aguir, Valmor Roberto Mastelaro

Abstract:

Zinc oxide (ZnO) pure or doped are one of the most promising metal oxide semiconductors for gas sensing applications due to the well-known high surface-to-volume area and surface conductivity. It was shown that ZnO is an excellent gas-sensing material for different gases such as CO, O2, NO2 and ethanol. In this context, pure and doped ZnO exhibiting different morphologies and a high surface/volume ratio can be a good option regarding the limitations of the current commercial sensors. Different studies showed that the sensitivity of metal-doped ZnO (e.g. Co, Fe, Mn,) enhanced its gas sensing properties. Motivated by these considerations, the aim of this study consisted on the investigation of the role of Co ions on structural, morphological and the gas sensing properties of nanostructured ZnO samples. ZnO and Zn1-xCoxO (0 < x < 5 wt%) thin films were obtained via the polymeric precursor method. The sensitivity, selectivity, response time and long-term stability gas sensing properties were investigated when the sample was exposed to a different concentration range of ozone (O3) at different working temperatures. The gas sensing property was probed by electrical resistance measurements. The long and short-range order structure around Zn and Co atoms were investigated by X-ray diffraction and X-ray absorption spectroscopy. X-ray photoelectron spectroscopy measurement was performed in order to identify the elements present on the film surface as well as to determine the sample composition. Microstructural characteristics of the films were analyzed by a field-emission scanning electron microscope (FE-SEM). Zn1-xCoxO XRD patterns were indexed to the wurtzite ZnO structure and any second phase was observed even at a higher cobalt content. Co-K edge XANES spectra revealed the predominance of Co2+ ions. XPS characterization revealed that Co-doped ZnO samples possessed a higher percentage of oxygen vacancies than the ZnO samples, which also contributed to their excellent gas sensing performance. Gas sensor measurements pointed out that ZnO and Co-doped ZnO samples exhibit a good gas sensing performance concerning the reproducibility and a fast response time (around 10 s). Furthermore, the Co addition contributed to reduce the working temperature for ozone detection and improve the selective sensing properties.

Keywords: cobalt-doped ZnO, nanostructured, ozone gas sensor, polymeric precursor method

Procedia PDF Downloads 230

Authors: H. Shokouhmand, A. Ghanami

Abstract:

A heat pipe is simple heat transfer device which combines the conduction and phase change phenomena to control the heat transfer without any need for external power source. At a hot surface of the heat pipe, the liquid phase absorbs heat and changes to the vapor phase. The vapor phase flows to condenser region and with the loss of heat changes to the liquid phase. Due to gravitational force the liquid phase flows to the evaporator section. In HVAC systems, the working fluid is chosen based on the operating temperature. The heat pipe has significant capability to reduce the humidity in HVAC systems. Each HVAC system which uses the heater, humidifier, or dryer is a suitable nominate for the utilization of heat pipes. Generally, heat pipes have three main sections: condenser, adiabatic region, and evaporator. Performance investigation and optimization of heat pipes operation in order to increase their efficiency is crucial. In the present article, a parametric study is performed to improve the heat pipe performance. Therefore, the heat capacity of the heat pipe with respect to geometrical and confining parameters is investigated. For the better observation of heat pipe operation in HVAC systems, a CFD simulation in Eulerian-Eulerian multiphase approach is also performed. The results show that heat pipe heat transfer capacity is higher for water as working fluid with the operating temperature of 340 K. It is also showed that the vertical orientation of heat pipe enhances its heat transfer capacity.

Keywords: heat pipe, HVAC system, grooved heat pipe, heat pipe limits

Procedia PDF Downloads 422

Authors: Hanen Bouaziz, Moez Rafrafi, Ghada Ben Salah, Kamel Jamoussi, Tahia Boudawara, Najiba Zeghal

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The present study investigated the protective role of Hyparrhenia hirta against sodium nitrate (NaNO3)-induced nephrotoxicity. A high-performance liquid chromatography coupled with a mass spectrometer (HPLC-MS) method was developed to separate and identify flavonoids in Hyparrhenia hirta. Seven flavonoids were identified as 3-O-methylquercetin, luteolin-7-O-glucoside, luteolin, apigenin-7-O-glucoside, apigenin-8-C-glucoside, luteolin-8-C-glucoside and luteolin-6-C-glucoside. Wistar rats were randomly divided into three groups: a control group and two treated groups during 50 days with NaNO3 administered either alone in drinking water or co-administered with Hyparrhenia hirta. NaNO3 treatment induced a significant increase in plasma levels of creatinine, urea and uric while urinary level decreased significantly. Nephrotoxicity induced by NaNO3 was characterized by significant increase in creatinine clearance. In parallel, a significant increase in malondialdehyde level along with a concomitant decrease in total glutathione content and superoxide dismutase, catalase and glutathione peroxidase activities were observed in the kidney after NaNO3 treatment. The histopathological changes in kidney after NaNO3 administration were shrunken. There were renal tubule cell degeneration and infiltration of mononuclear cells. Most glomeruli revealed shrinkage, a wide capsular space and a peri-glomerular mononuclear cells infiltration. Hyparrhenia hirta supplementation showed a remarkable amelioration of the abnormalities cited above. The results concluded that the treatment with Hyparrhenia hirta had a significant role in protecting the animals from nitrate-induced kidney dysfunction.

Keywords: flavonoids, hyparrhenia hirta, kidney, nitrate toxicity, oxidative stress, rat

Procedia PDF Downloads 430

Authors: Ayomide A Sijuade, Nafiza Anjum

Abstract:

The rising demand to meet the need for clean and sustainable energy solutions has led the market to create effective energy storage technologies. In this study, we look at the possibility of using a heterostructure made of polyaniline (PANI), titanium carbide (Ti₃C₂), and vanadium carbide (V₂C) for energy storage devices. V₂C is a two-dimensional transition metal carbide with remarkable mechanical and electrical conductivity. Ti₃C2 has solid thermal conductivity and mechanical strength. PANI, on the other hand, is a conducting polymer with customizable electrical characteristics and environmental stability. Layer-by-layer assembly creates the heterostructure of V₂C, Ti₃C₂, and PANI, allowing for precise film thickness and interface quality control. Structural and morphological characterization is carried out using X-ray diffraction, scanning electron microscopy, and atomic force microscopy. For energy storage applications, the heterostructure’s electrochemical performance is assessed. Electrochemical experiments, such as cyclic voltammetry and galvanostatic charge-discharge tests, examine the heterostructure’s charge storage capacity, cycle stability, and rate performance. Comparing the heterostructure to the individual components reveals better energy storage capabilities. V₂C, Ti₃C₂, and PANI synergize to increase specific capacitance, boost charge storage, and prolong cycling stability. The heterostructure’s unique arrangement of 2D materials and conducting polymers promotes effective ion diffusion and charge transfer processes, improving the effectiveness of energy storage. The heterostructure also exhibits remarkable electrochemical stability, which minimizes capacity loss after repeated cycling. The longevity and long-term dependability of energy storage systems depend on this quality. By examining the potential of V₂C, Ti₃C₂, and PANI heterostructures, the results of this study expand energy storage technology. These materials’ specialized integration and design show potential for use in hybrid energy storage systems, lithium-ion batteries, and supercapacitors. Overall, the development of high-performance energy storage devices utilizing V₂C, Ti₃C₂, and PANI heterostructures is clarified by this research, opening the door to the realization of effective, long-lasting, and eco-friendly energy storage solutions to satisfy the demands of the modern world.

Keywords: MXenes, energy storage materials, conductive polymers, composites

Procedia PDF Downloads 37

Authors: Erfan Asghari Fesaghandis, Reza Ghaffari Adli, Abbas Kianvash, Hossein Aghajani, Homa Homaie

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NiTi alloys possess magnificent superelastic, shape memory, high strength and biocompatible properties. For improving mechanical properties, foremost, superelasticity behavior, heat treatment process is carried out. In this paper, two different heat treatment methods were undertaken: (1) solid solution, and (2) aging. The effect of each treatment in a constant time is investigated. Five samples were prepared to study the structure and optimize mechanical properties under different time and temperature. For measuring the upper plateau stress, lower plateau stress and residual strain, tensile test is carried out. The samples were aged at two different temperatures to see difference between aging temperatures. The sample aged at 500 °C has a bigger crystallite size and lower amount of Ni which causes the mentioned sample to possess poor pseudo elasticity behaviour than the other aged sample. The sample aged at 460 °C has shown remarkable superelastic properties. The mentioned sample’s higher plateau is 580 MPa with the lowest residual strain (0.17%) while other samples have possessed higher residual strains. X-ray diffraction was used to investigate the produced phases.

Keywords: heat treatment, phase transformation, superelasticity, NiTi alloy

Procedia PDF Downloads 116

Authors: L. R. Shobin, S. Manivannan

Abstract:

One dimensional silver nanowires and nanoparticles gained more interest in developing transparent conducting films, catalysis, biological and chemical sensors. Silver nanostructures can be synthesized by varying reaction conditions such as the precursor concentration, molar ratio of the surfactant, injection speed of silver ions, etc. in the polyol process. However, the reaction proceeds for greater than 2 hours for the formation of silver nanowires. The introduction of etchant in the medium promotes the growth of silver nanowires from silver nanoparticles along the [100] direction. Rapid growth of silver nanowires is accomplished using the Cl- ions from NaCl and polyvinyl pyrrolidone (PVP) as surfactant. The role of Cl- ion was investigated in the growth of the nanostructured silver. Silver nanoparticles (<100 nm) were harvested from glycerol medium in the absence of Cl- ions. Trace amount of Cl- ions (2.5 mM -NaCl) produced the edge joined nanowires of length upto 2 μm and width ranging from 40 to 65 nm. Formation and rapid growth (within 25 minutes) of long, uniform silver nanowires (upto 5 μm) with good yield were realized in the presence of 5 mM NaCl at 200ºC. The growth of nanostructures was monitored by UV-vis-NIR spectroscopy. Scanning and transmission electron microscopes reveal the morphology of the silver nano harvests. The role of temperature in the reduction of silver ions, growth mechanism for nanoparticles, edge joined and straight nanowires will be discussed.

Keywords: silver nanowires, glycerol mediated polyol process, scanning electron microscopy, UV-Vis- NIR spectroscopy, transmission electron microscopy

Procedia PDF Downloads 293

Authors: Zeynep R. Ege, Aydin Akan, Faik N. Oktar, Betul Karademir, Oguzhan Gunduz

Abstract:

Early detection of cancer could save human life and quality in insidious cases by advanced biomedical imaging techniques. Designing targeted detection system is necessary in order to protect of healthy cells. Electrospun nanofibers are efficient and targetable nanocarriers which have important properties such as nanometric diameter, mechanical properties, elasticity, porosity and surface area to volume ratio. In the present study, indocyanine green (ICG) organic dye was stabilized and encapsulated in polymer matrix which polyethylene oxide (PEO) and chitosan (CHI) multilayer nanofibers via co-axial electrospinning method at one step. The co-axial electrospun nanofibers were characterized as morphological (SEM), molecular (FT-IR), and entrapment efficiency of Indocyanine Green (ICG) (confocal imaging). Controlled release profile of PEO/CHI/ICG nanofiber was also evaluated up to 40 hours.

Keywords: chitosan, coaxial electrospinning, controlled releasing, drug delivery, indocyanine green, polyethylene oxide

Procedia PDF Downloads 154

Authors: P. Murugesan, G. Venkateswaran, V. A. Shanmuga Selvan

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Water used for brewing tea plays a major role in the quality of tea. Water with higher hardness gives very dark coloured brew. This study was conducted to determine the effect of water hardness and free residual chlorine on the quality of black tea liquor. Theaflavin (TF) and Thearubigin (TR) levels are lower in comparison with the tea brewed in distilled water. At the same time, there is an increase in High Polymerized Substance (HPS) and Total Liquor Colour (TLC). While water with higher hardness has a negative impact on tea brew, water with high concentration of free residual chlorine did not affect the quality of tea brew.

Keywords: Theaflavin, Thearubigin, high polymerised substance, total liquor colour, hardness, residual chlorine

Procedia PDF Downloads 248

Authors: Javier Delgado-Gonzaga, Wilfrido Rivera, David Juárez-Romero

Abstract:

Cooling and water purification are processes that have contributed to the economic and social development of the modern world. However, these processes require a significant amount of energy globally. Nowadays, absorption heat pumps have been studied with great interest since they are capable of producing cooling and/or purifying water from low-temperature energy sources such as industrial waste heat or renewable energy. In addition, absorption heat pumps require negligible amounts of electricity for their operation and generally use working fluids that do not represent a risk to the environment. The objective of this work is to evaluate a system that integrates an absorption heat transformer and an absorption cooling system to produce fresh water and cooling from a low-temperature heat source. Both cycles operate with the working pair LiBr-H2O. The integration is possible through the interaction of the LiBr-H2O solution streams between both cycles and also by recycling heat from the absorption heat transformer to the absorption cooling system. Mathematical models were developed to compare the performance of four different configurations. The results showed that the configuration in which the hottest streams of LiBr-H2O solution preheated the coldest streams in the economizers of both cycles was one that achieved the best performance. The interaction of the solution currents and the heat recycling analyzed in this work serves as a record of the possibilities of integration between absorption cycles for cogeneration.

Keywords: absorption heat transformer, absorption cooling system, water desalination, integrated system

Procedia PDF Downloads 66

Authors: S. Mohamed Rabeek, Mi Kyoung Park, M. Annamalai Arasu

Abstract:

This paper presents a design of a wireless read out system for tracking the frequency shift of the polymer coated piezoelectric micro electromechanical resonator due to gas absorption. The measure of this frequency shift indicates the percentage of a particular gas the sensor is exposed to. It is measured using an oscillator and an FPGA based frequency counter by employing the resonator as a frequency determining element in the oscillator. This system consists of a Gas Sensing Wireless Readout (GSWR) and an USB Wireless Transceiver (UWT). GSWR consists of an oscillator based on a trans-impedance sustaining amplifier, an FPGA based frequency readout, a sub 1GHz wireless transceiver and a micro controller. UWT can be plugged into the computer via USB port and function as a wireless module to transfer gas sensor data from GSWR to the computer through its USB port. GUI program running on the computer periodically polls for sensor data through UWT - GSWR wireless link, the response from GSWR is logged in a file for post processing as well as displayed on screen.

Keywords: gas sensor, GSWR, micromechanical system, UWT, volatile emissions

Procedia PDF Downloads 471

Authors: Penchuk A. Vovkanych

Abstract:

The adaptive changes in the respiratory system provide the background for the increase of aerobic capacity and sport results on the middle and long distances runners. Effect of such adaptive changes in the sport orienteering remains poorly investigated. Therefore our study was undertaken to reveal the adaptive changes in the respiration indices of high skilled orienteer athletes.

Keywords: adaptation, external, functional state, respiration, running, sport orienteering

Procedia PDF Downloads 472

Authors: Samuel Matylewicz, K. W. Goossen

Abstract:

The deployment of white or cool (high albedo) roofing is a common energy savings recommendation for a variety of buildings all over the world. Here, the effect of a white roof on the energy savings of an ice rink facility in the northeastern US is determined by measuring the effect of solar irradiance on the consumption of the rink's ice refrigeration system. The consumption of the refrigeration system was logged over a year, along with multiple weather vectors, and a statistical model was applied. The experimental model indicates that the expected savings of replacing the existing grey roof with a white roof on the consumption of the refrigeration system is only 4.7 %. This overall result of the statistical model is confirmed with isolated instances of otherwise similar weather days, but cloudy vs. sunny, where there was no measurable difference in refrigeration consumption up to the noise in the local data, which was a few percent. This compares with a simple theoretical calculation that indicates 30% savings. The difference is attributed to a lack of convective cooling of the roof in the theoretical model. The best experimental model shows a relative effect of the weather vectors dry bulb temperature, solar irradiance, wind speed, and relative humidity on refrigeration consumption of 1, 0.026, 0.163, and -0.056, respectively. This result can have an impact on decisions to apply white roofing to refrigerated buildings in general.

Keywords: cool roofs, solar cooling load, refrigerated buildings, energy-efficient building envelopes

Procedia PDF Downloads 116

Authors: Lu-Chen Yeh‚ Jui-Ming Yeh

Abstract:

In this manuscript, we produced neat electrospun poly(o-methoxyaniline) (POMA) fibers and utilized it for applying the growth of neural stem cells. The transparency and morphology of as-prepared POMA fibers were characterized by UV-visible spectroscopy and scanning electron microscopy, respectively. It was found to have no adverse effects on the long-term proliferation of the neural stem cells (NSCs), retained the ability to self-renew, and exhibit multi-potentiality. Results of immunofluorescence staining studies confirmed that POMA electrospun fibers could provide a great environment for NSCs and enhance its differentiation.

Keywords: electrospun, polyaniline, neural stem cell, differentiation

Procedia PDF Downloads 391

Authors: Urom Scholastica Mgbo, Ifeanyichukwu, Vivian, Anaba, Uchemadu Martins, Arusiaba, Nelson Chijioke

Abstract:

The study was investigated to determine the growth performance , haematological and serum biochemistry of broiler fed graded levels of cocoyam (Xanthosoma sagittifolium). One hundred and twenty (120) day old broiler chicks of Anak strain were used for the study. The birds were randomly divided into 4 treatment groups of 30 birds per group, and each group was further divided into 3 replicates of 10 birds per replicate in group. Cooked cocoyam was used to formulate diets at inclusion levels of 0.00% for T1 (control), while T2, T3 and T4 contained 10.00%, 20.00% and 30.00% inclusion of cocoyam in partial replacement of maize in a Completely Randomized Design (CRD). At the end of the research, the haematological indices of broiler showed that packed cell volume (PCV) of birds fed diets 1(42.26%) and 3 (42.42%) were significantly (p<0.05) higher than birds fed diets 2 (39.72%) and 4 (38.78%).The Haemoglobin (Hb) of birds fed diets 3 (12.58g/dl) and 4 (12.26g/dl) were significantly (p<0.05) higher than birds fed diets 1 (11.60g/dl) and 2 (11.42g/dl). The values of the white blood cell (WBC) of the broiler chickens placed on cocoyam diet increased significantly (P<0.05) compared with the values obtained in the control (T1) . The serum protein value for birds fed diet I (5.45g/dl) were statistically (P>0.05) similar to those fed diets 2 (5.10g/dl) and 3 (5.38g/dl) but differ significantly (P<0.05) from diet 4 (4.97g/dl) which had the least protein value. Final weight of the birds showed that diet 4 (2370.85g) had the highest (P<0.05) value which was followed closely by diet 3 (2225.55g), while birds fed diets 1 (2165.70g) and diet 2 (2145.00g) recorded the least values Similar pattern was observed in the weight gain of the birds. Birds fed diet 4 (2270.30g) had higher (P<0.05) value, followed by birds on diet 3 (2125.45g), while birds fed diet 1 (2065.15g) and 2 (2044.90g) had the least values.. This study showed that birds fed diet 3 (50.60g) and diet 4 (54.05g) gave significantly (P<0.05) higher weight than the control diet (49.17g). There was significant (P<0.05) difference among the treatments for feed conversion ratio (FCR), were birds fed diet 4 (1.74) performed better, having the least feed conversion ratio. Economics of broiler chickens showed that Cost/kg of feed favored diet 4 (₦158.65) followed by diets 3 (₦165.95), 2 (₦178.52) and control diet 1 (₦197.14). From the result, the higher weight recorded in T4 4 showed that cocoyam meal can successfully replace maize up to 30% in the diet of broiler chickens. The low cost recorded in cocoyam based diets showed that the diets were more economical and beneficial compared to control diet 1. Therefore, feeding diet 4 (30%) cocoyam meal as replacement of maize in broiler chickens is recommended.

Keywords: cocoyam, growth, heamatology, serum biochemistry

Procedia PDF Downloads 97

Authors: Farhina Haque, Chanyeop Park

Abstract:

The high efficiency, high field, and high power density provided by wide bandgap (WBG) semiconductors and advanced power electronic converter (PEC) topologies enabled the dynamic control of power in medium to high voltage systems. Although WBG semiconductors outperform the conventional Silicon based devices in terms of voltage rating, switching speed, and efficiency, the increased voltage handling properties, high dv/dt, and compact device packaging increase local electric fields, which are the main causes of partial discharge (PD) in the advanced medium and high voltage applications. PD, which occurs actively in voids, triple points, and airgaps, is an inevitable dielectric challenge that causes insulation and device aging. The aging process accelerates over time and eventually leads to the complete failure of the applications. Hence, it is critical to mitigating PD. Sharp edges, airgaps, triple points, and bubbles are common defects that exist in any medium to high voltage device. The defects are created during the manufacturing processes of the devices and are prone to high-electric-field-induced PD due to the low permittivity and low breakdown strength of the gaseous medium filling the defects. A contemporary approach of mitigating PD by neutralizing electric fields in high power density applications is introduced in this study. To neutralize the locally enhanced electric fields that occur around the triple points, airgaps, sharp edges, and bubbles, electrets are developed and incorporated into high voltage applications. Electrets are electric fields emitting dielectric materials that are embedded with electrical charges on the surface and in bulk. In this study, electrets are fabricated by electrically charging polyvinylidene difluoride (PVDF) films based on the widely used triode corona discharge method. To investigate the PD mitigation performance of the fabricated electret films, a series of PD experiments are conducted on both the charged and uncharged PVDF films under square voltage stimuli that represent PWM waveform. In addition to the use of single layer electrets, multiple layers of electrets are also experimented with to mitigate PD caused by higher system voltages. The electret-based approach shows great promise in mitigating PD by neutralizing the local electric field. The results of the PD measurements suggest that the development of an ultimate solution to the decades-long dielectric challenge would be possible with further developments in the fabrication process of electrets.

Keywords: electrets, high power density, partial discharge, triode corona discharge

Procedia PDF Downloads 192

Authors: L. N. Shubha, M. Kalpana, P. Madhusudana Rao

Abstract:

Polyaniline/gold (PANI/Au) nanocomposite was prepared by in-situ chemical oxidation polymerization method. The synthesis involved the formation of polyaniline-gold nanocomposite, by in-situ redox reaction and the dispersion of gold nano particles throughout the polyaniline matrix. The nanocomposites were characterized by XRD, FTIR, TEM and UV-visible spectroscopy. The characteristic peaks in FTIR and UV-visible spectra confirmed the expected structure of polymer as reported in the literature. Further, transmission electron microscopy (TEM) confirmed the formation of gold nano particles. The crystallite size of 30 nm for nanoAu was supported by the XRD pattern. Further, the A.C. conductivity, dielectric constant (€’(w)) and dielectric loss (€’’(w)) of PANI/Au nano composite was measured using impedance analyzer. The effect of doping on the conductivity was investigated. The antibacterial activity was examined for this nano composite and it was observed that PANI/Au nanocomposite could be used as an antibacterial agent.

Keywords: AC-conductivity, anti-microbial activity, dielectric constant, dielectric loss, polyaniline/gold (PANI/AU) nanocomposite

Procedia PDF Downloads 366

Authors: Hakim Chayeb

Abstract:

Macrophages (Mo) play an essential role in host defense against pathogens. These inflammatory cells contain a large group of inducible enzymes such as NO synthase (NOS). This study was conducted to characterize experimentally induced inflammation in vivo by lipopolysaccharides (LPS). LPS is an essential component of the outer membrane of Gram-negative bacteria and a potent inducer of macrophage. Except control rats, all rats received different doses of LPS intra-peritoneally. The involvement of inducible NO synthase (iNOS) and constitutive (cNOS ) in the modulation of the inflammatory response was studied by treating the rats with L-NAME (non-selective NOS inhibitor) or aminoguanidine (AG inhibitor of iNOS). Inhibitors were injected 24 hours before LPS administration. The results showed that esterase activity (a marker of macrophage infiltration) which is induced by LPS is reduced by AG, was potentiated by treatment with L-NAME in tissue homogenates of the liver, kidney and spleen. Meanwhile, the concentrations of nitric oxide (NO) induced by LPS were reduced with AG and are completely inhibited with L-NAME in the tissues studied. NO concentrations and plasma transaminase levels have undergone remarkable increases in rats treated with LPS alone. However, the AG significantly reduced these rates. Our results highlighted the role of NO synthase inhibitors in reducing of inflammatory responses that characterize many infectious diseases.

Keywords: aminoguanidine, esterase, LPS, L-NAME, macrophage, nitric oxide

Procedia PDF Downloads 248