1) Iron oxide nanoparticles are capable of generating reactive oxygen species through Fenton and Haber-Weiss reactions when exposed to an alternating magnetic field, which increases the temperature locally around the nanoparticles.
2) The study observed an increase in degradation of methylene blue by magnetite nanoparticles in the presence of hydrogen peroxide and an alternating magnetic field, indicating increased reactive oxygen species generation.
3) The increase in reactive oxygen species generation compared to the predicted temperature-dependent rate showed a decrease with increased nanoparticle concentration and exposure time due to agglomeration, which decreases surface area available for reaction.
Chemiluminescence is the emission of light from a chemical reaction and can be used for analytical testing. It involves reactions that produce electronically excited molecules that then decay to ground state while emitting photons of light. Common substances used include luminol, acridinium esters, and ruthenium derivatives. When oxidized, typically with hydrogen peroxide, intermediates are produced in excited states. As they return to ground state, light is emitted. This light can be measured with high sensitivity for applications like immunoassays, liquid chromatography detection, and clinical diagnostics. Advantages include stability, low toxicity, high sensitivity down to attomole and zeptomole levels, and fast results.
Formation and annihilation of E4 centers in ZnO - Influence of hydrogen - A. ...Chidanand Bhoodoo
The document discusses the formation and annealing behavior of E4 centers in zinc oxide (ZnO) under the influence of hydrogen implantation. It finds that the concentration of E4 centers, which have an energy level of 0.57 eV below the conduction band, increases linearly with proton and deuterium ion fluence during implantation. Isothermal annealing experiments show that the E4 centers exhibit first-order kinetics with an activation energy of 0.6 eV, and the annealing rate is strongly enhanced by higher hydrogen fluence. A model where interstitial hydrogen enhances the migration and reaction of E4 centers describes the experimental observations well. Based on theoretical predictions and previous work, the document tentatively assigns the E4 center to the oxygen
The E3 center in zinc oxide - Evidence for involvement of hydrogen - A. Hupfe...Chidanand Bhoodoo
This document discusses evidence that hydrogen is involved in the formation of the E3 defect center in zinc oxide (ZnO). Proton implantation into hydrothermally grown ZnO samples was found to significantly increase the concentration of E3 centers, as measured by capacitance-voltage profiling and deep level transient spectroscopy. The concentration of E3 centers increased by over an order of magnitude in samples implanted with protons compared to unimplanted control samples. Implantation with helium ions did not produce a similar increase in E3 centers. This provides strong evidence that hydrogen plays a role in the formation of E3 centers in ZnO.
This document discusses luminescence and various types of luminescence including chemiluminescence. It provides examples of chemiluminescence in nature from fireflies, marine microorganisms, and anglerfish. The document then examines the chemical reaction underlying chemiluminescence and provides examples of its applications in forensic science, biomedical research, glow sticks, gas-phase reactions, and DNA hybridization detection.
Water as a solvent in microwave assisted organic synthesisPrashantChavan93
Prashant Chavan
Reserach Scholar
M.S.(Pharm) in Medicinal Chemistry
National Institute of Pharmaceutical Education and Research Mohali, Punjab (India) 160062
mcm20_prashant@niper.ac.in
The document summarizes a study comparing the electrical properties of platinum interconnects deposited by electron beam induced deposition using two different precursors: a carbon-free precursor (Pt(PF3)4) and a standard organometallic precursor ((CH3)3Pt(CpCH3)). Interconnects deposited with the carbon-free precursor exhibited significantly improved electrical performance, including lower resistivity (0.24 x 10-3 Ω cm vs 0.2 Ω cm for the standard precursor) and higher maximum current density (1.87 x 107 A/cm2 vs 9.44 x 105 A/cm2). Post-deposition annealing was found to further improve the electrical properties by inducing crystallization and
This document discusses chemiluminescence, which is the emission of light from a chemical reaction without significant heat production. It describes how chemiluminescence occurs when a reactant kicks an electron in an atom to an excited state, and the electron then returns to the ground state emitting a photon of light. Common examples of chemiluminescent reactions involve luminol, isoluminol, and luciferin. The document outlines applications of chemiluminescence including immunoassays, DNA hybridization detection, western blotting, forensic analysis to detect blood, and food analysis to detect pesticides. It also notes some limitations such as light leaks and high intensity light saturation effects.
The document summarizes research conducted on an Anodic Aluminum Oxide (AAO) chemical sensor. The sensor was constructed and tested at Northern Illinois University to detect differences between alcohols like isopropyl and methanol by measuring electrical impedance responses. Tests measured the adsorption and desorption rates of chemicals on the sensor surface. Results showed the sensor could distinguish between chemicals and further testing could provide more understanding of sensor interactions and responses.
Chemiluminescence is the emission of light from a chemical reaction and can be used for analytical testing. It involves reactions that produce electronically excited molecules that then decay to ground state while emitting photons of light. Common substances used include luminol, acridinium esters, and ruthenium derivatives. When oxidized, typically with hydrogen peroxide, intermediates are produced in excited states. As they return to ground state, light is emitted. This light can be measured with high sensitivity for applications like immunoassays, liquid chromatography detection, and clinical diagnostics. Advantages include stability, low toxicity, high sensitivity down to attomole and zeptomole levels, and fast results.
Formation and annihilation of E4 centers in ZnO - Influence of hydrogen - A. ...Chidanand Bhoodoo
The document discusses the formation and annealing behavior of E4 centers in zinc oxide (ZnO) under the influence of hydrogen implantation. It finds that the concentration of E4 centers, which have an energy level of 0.57 eV below the conduction band, increases linearly with proton and deuterium ion fluence during implantation. Isothermal annealing experiments show that the E4 centers exhibit first-order kinetics with an activation energy of 0.6 eV, and the annealing rate is strongly enhanced by higher hydrogen fluence. A model where interstitial hydrogen enhances the migration and reaction of E4 centers describes the experimental observations well. Based on theoretical predictions and previous work, the document tentatively assigns the E4 center to the oxygen
The E3 center in zinc oxide - Evidence for involvement of hydrogen - A. Hupfe...Chidanand Bhoodoo
This document discusses evidence that hydrogen is involved in the formation of the E3 defect center in zinc oxide (ZnO). Proton implantation into hydrothermally grown ZnO samples was found to significantly increase the concentration of E3 centers, as measured by capacitance-voltage profiling and deep level transient spectroscopy. The concentration of E3 centers increased by over an order of magnitude in samples implanted with protons compared to unimplanted control samples. Implantation with helium ions did not produce a similar increase in E3 centers. This provides strong evidence that hydrogen plays a role in the formation of E3 centers in ZnO.
This document discusses luminescence and various types of luminescence including chemiluminescence. It provides examples of chemiluminescence in nature from fireflies, marine microorganisms, and anglerfish. The document then examines the chemical reaction underlying chemiluminescence and provides examples of its applications in forensic science, biomedical research, glow sticks, gas-phase reactions, and DNA hybridization detection.
Water as a solvent in microwave assisted organic synthesisPrashantChavan93
Prashant Chavan
Reserach Scholar
M.S.(Pharm) in Medicinal Chemistry
National Institute of Pharmaceutical Education and Research Mohali, Punjab (India) 160062
mcm20_prashant@niper.ac.in
The document summarizes a study comparing the electrical properties of platinum interconnects deposited by electron beam induced deposition using two different precursors: a carbon-free precursor (Pt(PF3)4) and a standard organometallic precursor ((CH3)3Pt(CpCH3)). Interconnects deposited with the carbon-free precursor exhibited significantly improved electrical performance, including lower resistivity (0.24 x 10-3 Ω cm vs 0.2 Ω cm for the standard precursor) and higher maximum current density (1.87 x 107 A/cm2 vs 9.44 x 105 A/cm2). Post-deposition annealing was found to further improve the electrical properties by inducing crystallization and
This document discusses chemiluminescence, which is the emission of light from a chemical reaction without significant heat production. It describes how chemiluminescence occurs when a reactant kicks an electron in an atom to an excited state, and the electron then returns to the ground state emitting a photon of light. Common examples of chemiluminescent reactions involve luminol, isoluminol, and luciferin. The document outlines applications of chemiluminescence including immunoassays, DNA hybridization detection, western blotting, forensic analysis to detect blood, and food analysis to detect pesticides. It also notes some limitations such as light leaks and high intensity light saturation effects.
The document summarizes research conducted on an Anodic Aluminum Oxide (AAO) chemical sensor. The sensor was constructed and tested at Northern Illinois University to detect differences between alcohols like isopropyl and methanol by measuring electrical impedance responses. Tests measured the adsorption and desorption rates of chemicals on the sensor surface. Results showed the sensor could distinguish between chemicals and further testing could provide more understanding of sensor interactions and responses.
This document summarizes research on controlling the size of germanium nanowires through the use of ternary alloy catalysts. Specifically:
1) Au-Ag-Ge layered thin films were used to simultaneously manipulate the solute concentration and equilibrium concentration of Ge in the catalyst, increasing supersaturation and enabling the growth of high aspect ratio Ge nanowires.
2) Colloidal Au0.75-Ag0.25 nanoparticles deposited on a Ge film also manipulated concentration and equilibrium concentration, producing nanowires with more uniform diameters than thin films.
3) In situ TEM heating experiments on the nanowires directly determined the equilibrium concentrations of Ge in the Au-Ag-Ge
Thermoluminescence in Pure and Nd+3 + K+ Doped Lead Germanate Single CrystalsAI Publications
Pure lead germanate was grown by Zochralski’stechnique.Nd+3 + K+ doped lead germanate was grown for comparative studies. Thermoluminescence studies were conducted on pure lead germanate and Nd+3 + K+ doped lead germanate. Thermoluminescence in pure lead germanate single crystals (LG) and Nd+3 + K+ doped lead germanate single crystals (DDLG) has been measured in terms of photomultiplier output current on Thermoluminescence Set Up. Thermoluminescence studies of LG revealed an increasing trend of Thermoluminescence output, with increasing temperature and sharp consistent maxima at 50°C and 100°C. TL studies of DDLG revealed a decreasing trend of Thermoluminescence output, with increasing temperature and a sharp consistent peak at 100°C and 120°C. It was further noted that doping increased Thermoluminescence output. Thermoluminescence in ferroelectric lead germanate was attributed to change in polarization with change in temperature and creation of defect states.
This document summarizes research on the eutectic behavior of binary mixtures of polycyclic aromatic hydrocarbons (PAHs). Differential scanning calorimetry was used to measure the melting points and fusion enthalpies of acenaphthene-fluorene and fluorene-phenanthrene mixtures of varying compositions. The enthalpies of fusion of the eutectic mixtures were found to be lower than predicted for ideal mixtures, indicating an interaction energy between the compounds. Future work will further investigate the degrees of deviation from ideal mixture behavior and intermolecular forces involved.
This document discusses chemiluminescence reactions that emit light. It defines chemiluminescence as a light-emitting chemical reaction and distinguishes it from other types of luminescence. Examples of gas-phase and liquid-phase chemiluminescent reactions are provided, such as the reaction of nitric oxide with ozone that produces excited nitrogen dioxide and emits light. The document also explores the chemiluminescent reaction involved in glowsticks and the firefly luciferase reaction.
The document summarizes the results of a study that measured the standard enthalpies of ionization of 21 substituted anilinium ions using calorimetry. It found that both the enthalpies and entropies of ionization correlated well with the Gibbs free energies of ionization. The experimental results were analyzed according to Hepler's theory of substituent effects and compared to predictions of electrostatic theory.
Chemiluminescence in blood stain detection pptMaria Donohue
Luminol is a chemical that emits light through chemiluminescence when exposed to certain metals like iron found in blood. When sprayed at a crime scene, luminol can detect bloodstains even if attempts were made to clean them up due to hemoglobin's stability. The oxidation reaction of luminol gains oxygen while losing nitrogen and hydrogen, producing an excited state compound that emits blue light as electrons return to the ground state. However, luminol may also react with other substances like bleach and can destroy genetic evidence in blood, so it is best used as a last resort to support physical evidence at a crime scene.
Chemiluminescence is the production of light from a chemical reaction. Two chemicals react to form an excited intermediate state that releases energy in the form of photons as it returns to a stable ground state. This light emission occurs without much heat release. Chemiluminescent reactions can be grouped into chemical reactions using synthetic compounds, bioluminescent reactions from living organisms like fireflies, and electrochemiluminescent reactions involving electrical current. Forensic scientists use the chemiluminescent reaction of luminol to detect traces of blood at crime scenes by spraying a mixture that causes a blue glow in the presence of iron from hemoglobin.
This document summarizes research on infrared electroluminescence from GeSn heterojunction diodes grown by molecular beam epitaxy. Specifically, it reports on p-n heterojunction diodes fabricated from boron-doped p-type GeSn layers containing 8% Sn grown on n-type Ge substrates. Electroluminescence was observed from these diodes with a peak emission at 0.57 eV (2.15 microns). The emission intensity increased with higher drive currents and lower device temperatures. Total emitted power from a single edge facet was measured to be 54 microwatts at an applied peak current of 100 mA at 100 K. These results suggest GeSn materials may be useful for practical light
Kinetic modelling of nitrate removal from aqueous solution during electrocoag...Alexander Decker
This document discusses a study that aimed to model nitrate removal from aqueous solutions using electrocoagulation. Experiments were conducted to treat a synthetic solution containing 150 mg/L of nitrate using iron electrodes under various conditions. Kinetic and adsorption models were tested to determine which best fit the nitrate removal data. The results showed pseudo-second order kinetics and the Freundlich isotherm provided the best fits. Nitrate removal efficiency increased with reaction time and current density.
Comparison of hormonal assay by ELISA , ELFA and ECLrijaa
The document discusses various methods for hormone measurement and immunoassay techniques. It explains that hormone assays are important for clinical diagnosis and treatment monitoring. While early methods like bioassay and chemical analysis had low sensitivity, radioimmunoassay (RIA) introduced in 1959 improved detection. However, due to health risks, safer alternatives were sought. Enzyme-linked immunosorbent assay (ELISA) was developed in the 1970s as a replacement for RIA using enzymes rather than radioisotopes. More recent techniques like chemiluminescence, fluorescence, and electrochemiluminescence provide adequate sensitivity without radioactivity. The document compares the principles and properties of various immunoassay methods.
Electrochemical synthesis, characterization and electrochemical behaviour of...Alexander Decker
This document summarizes the electrochemical synthesis and characterization of new conducting copolymers composed of 2-methoxyaniline and 2,3-dihydrothieno[3,4-b][1,4]dioxine-2-carboxylic acid. Four copolymers were prepared at different monomer feed concentrations and characterized using cyclic voltammetry and infrared spectroscopy. In situ conductivity measurements on the copolymers revealed two transitions in conductivity. Homopolymers and copolymers were also investigated using in situ conductivity measurements.
This document outlines a project to design and fabricate a cooling system using ferrofluids. Ferrofluids are magnetic liquids that can be controlled using magnetic fields. The project involves synthesizing an aqueous ferrofluid and designing a system with a test section, pump, temperature sensors, heater and sink. When a temperature gradient is applied with a magnetic field, thermomagnetic convection occurs in the ferrofluid due to differences in magnetic susceptibility, enhancing heat transfer for cooling applications. The system is designed to test this effect and optimize heat transfer performance using ferrofluids.
The document summarizes a biology lab report on the effects of light intensity on photosynthesis. It finds that increasing the distance between the light source and plant (decreasing light intensity) decreases the rate of photosynthesis, as measured by counting oxygen bubbles. Specifically, it finds that the highest number of oxygen bubbles (and rate of photosynthesis) occurred at 10 cm between light and plant, and the lowest number of bubbles occurred at 50 cm. A graph shows an inverse relationship between distance from light and rate of photosynthesis. The experiment supports the hypothesis that increased light intensity leads to more light absorption and a higher photosynthesis rate.
Microwave assisted reaction km komal wahane k3komalwahane
Microwave assisted organic reactions can occur using solvents, under solvent-free conditions on solid supports, or using neat reactants. Reactions see increased rates due to microwave dielectric heating causing molecular polarization and rotation, generating heat. Key advantages are rapid reactions, high purity products, improved yields, and wider usable temperature ranges. Challenges include sudden temperature increases potentially distorting molecules or making reactions hazardous, and difficulty controlling heat.
This document reviews the use of microwave heating in organic synthesis. It begins with a brief history of heating methods in chemistry and an introduction to microwave theory. Key points are that microwaves directly couple with polar molecules to efficiently and uniformly heat reaction mixtures from the inside. This enables faster reactions and new reactivity compared to conventional thermal heating. The document discusses potential "microwave effects" including selective heating and hotspots, though most rate increases are due to purely thermal effects. It also reviews common microwave processing techniques like solventless reactions and highlights recent applications of microwave heating in areas like transition metal catalysis and combinatorial synthesis.
Andrew Ellis et al., Physica B, 385-386, (2006), 514 - 516.Duncan Gordon
This study investigated the physical aging of a blend of deuterated and hydrogenated poly(ethylene terephthalate) (PET) using differential scanning calorimetry (DSC) and small-angle neutron scattering (SANS). DSC showed an endothermic peak developed during aging and increased with aging time, indicating an increase in enthalpy. SANS revealed the radius of gyration decreased during aging, suggesting a change in molecular conformation. However, no difference was observed between aged and de-aged samples by SANS. The study thus showed physical aging of PET leads to changes in enthalpy and molecular conformation over time.
Enhancement of Heat Transfer in Heat Pipes using Al2O3/Benzene Based Nano-coo...RSIS International
Nowadays, the world is experiencing many challenges in solving heat transfer issues in various engineering systems. However, limited approaches are available to solve such challenges. To increase heat transfer, many researchers found that the Nanofluid is one of the feasible coolant which increase the working efficiency of many engineering devices. Electronic equipment dissipates enormous amount of heat while in operation which directly affect the work efficiency. To increase the efficiency it is mandatory to remove the heat by using proper coolant. Hence, the heat pipes are employed in electronic devices to remove the heat. To enhance the heat transfer in heat pipe nano-coolants may be used. In this present work, thermophysical properties of different types of base fluids with Aluminium oxide (Al2O3) Nanoparticles have been investigated with different concentrations of Nanoparticles (1-5 % by volume) at 300K temperature. The effective thermal conductivity of Nanofluids is compared with the base fluid and the results show enhancement in thermal conductivity. The thermal conductivity of Nanofluid is increased up to 3% at 300K with 1 % by volume concentration of nanoparticles and 15% at 5% by volume of concentration as compared to Benzene (C6H6) base fluid.
Microwave assisted synthesis is a green chemistry approach that uses microwave irradiation to accelerate chemical reactions. It has several advantages over traditional heating methods, such as faster reaction times, higher product purity, and lower energy usage. Microwaves work by causing polarization and ionic conduction in polar solvents and reagents, quickly generating heat. Common applications include coupling reactions like Suzuki, Heck, and Negishi reactions. SiC microwave vessels are preferable to Pyrex as they absorb microwaves more efficiently and allow for better temperature control of exothermic reactions.
This document discusses microwave assisted synthesis. Microwaves directly heat materials through ionic conduction and dipolar polarization. Microwave heating is more homogeneous than conventional heating methods. It allows for faster reactions, higher yields, lower energy consumption, and the ability to perform solvent-free reactions. Common organic reactions that can be carried out via microwave irradiation include Diels-Alder, ester hydrolysis, and nucleophilic substitutions. Microwave systems have advanced to enable both laboratory and industrial scale organic synthesis.
A new technique to measure oxygen reduction kinetics underneath coatings using hydrogen permeation from the back side. Huge step towards characterising buried interface reactivity.
The project will focus on synthesis of hexagonal structured pure phases of compositions: BaM1/3Ti2/3O3-δ and BaM1/6Ti5/6O3-δ, where M= Sc, In and Fe via different methods such as Solid state sintering and wet chemical route. The ultimate goal is to finding structure – functionality relationships within these proton and mixed conducting systems. A substantial effort will focus on search for and fabrication of new materials although the main part of the work will concentrate on detailed structural characterisation (rietveld refinement), impedance spectroscopy, infrared spectroscopy and thermogravimetric analysis.
In this paper, the analysis of optically responsive microfibers with uniaxially ordered liquid crystal (LC) molecules at their cores is discussed. LC microfibers were electrospun from a solution of poly(vinyl pyrrolidone) (PVP) and N-(4-methoxybenzylidene)-4$-butylaniline (MBBA) using absolute alcohol as a solvent. Two parallel copper (Cu) collectors were used to obtain ordered fibers. The microfibers with oriented LC molecules were well fabricated at a voltage of 5 kV. A thermal-optical analysis revealed that the fibers were responsive to temperature. The rise of temperature from nematic to isotropic phase of LC decreased the LC intensity under a polarized optical microscope (POM).
This document summarizes research on controlling the size of germanium nanowires through the use of ternary alloy catalysts. Specifically:
1) Au-Ag-Ge layered thin films were used to simultaneously manipulate the solute concentration and equilibrium concentration of Ge in the catalyst, increasing supersaturation and enabling the growth of high aspect ratio Ge nanowires.
2) Colloidal Au0.75-Ag0.25 nanoparticles deposited on a Ge film also manipulated concentration and equilibrium concentration, producing nanowires with more uniform diameters than thin films.
3) In situ TEM heating experiments on the nanowires directly determined the equilibrium concentrations of Ge in the Au-Ag-Ge
Thermoluminescence in Pure and Nd+3 + K+ Doped Lead Germanate Single CrystalsAI Publications
Pure lead germanate was grown by Zochralski’stechnique.Nd+3 + K+ doped lead germanate was grown for comparative studies. Thermoluminescence studies were conducted on pure lead germanate and Nd+3 + K+ doped lead germanate. Thermoluminescence in pure lead germanate single crystals (LG) and Nd+3 + K+ doped lead germanate single crystals (DDLG) has been measured in terms of photomultiplier output current on Thermoluminescence Set Up. Thermoluminescence studies of LG revealed an increasing trend of Thermoluminescence output, with increasing temperature and sharp consistent maxima at 50°C and 100°C. TL studies of DDLG revealed a decreasing trend of Thermoluminescence output, with increasing temperature and a sharp consistent peak at 100°C and 120°C. It was further noted that doping increased Thermoluminescence output. Thermoluminescence in ferroelectric lead germanate was attributed to change in polarization with change in temperature and creation of defect states.
This document summarizes research on the eutectic behavior of binary mixtures of polycyclic aromatic hydrocarbons (PAHs). Differential scanning calorimetry was used to measure the melting points and fusion enthalpies of acenaphthene-fluorene and fluorene-phenanthrene mixtures of varying compositions. The enthalpies of fusion of the eutectic mixtures were found to be lower than predicted for ideal mixtures, indicating an interaction energy between the compounds. Future work will further investigate the degrees of deviation from ideal mixture behavior and intermolecular forces involved.
This document discusses chemiluminescence reactions that emit light. It defines chemiluminescence as a light-emitting chemical reaction and distinguishes it from other types of luminescence. Examples of gas-phase and liquid-phase chemiluminescent reactions are provided, such as the reaction of nitric oxide with ozone that produces excited nitrogen dioxide and emits light. The document also explores the chemiluminescent reaction involved in glowsticks and the firefly luciferase reaction.
The document summarizes the results of a study that measured the standard enthalpies of ionization of 21 substituted anilinium ions using calorimetry. It found that both the enthalpies and entropies of ionization correlated well with the Gibbs free energies of ionization. The experimental results were analyzed according to Hepler's theory of substituent effects and compared to predictions of electrostatic theory.
Chemiluminescence in blood stain detection pptMaria Donohue
Luminol is a chemical that emits light through chemiluminescence when exposed to certain metals like iron found in blood. When sprayed at a crime scene, luminol can detect bloodstains even if attempts were made to clean them up due to hemoglobin's stability. The oxidation reaction of luminol gains oxygen while losing nitrogen and hydrogen, producing an excited state compound that emits blue light as electrons return to the ground state. However, luminol may also react with other substances like bleach and can destroy genetic evidence in blood, so it is best used as a last resort to support physical evidence at a crime scene.
Chemiluminescence is the production of light from a chemical reaction. Two chemicals react to form an excited intermediate state that releases energy in the form of photons as it returns to a stable ground state. This light emission occurs without much heat release. Chemiluminescent reactions can be grouped into chemical reactions using synthetic compounds, bioluminescent reactions from living organisms like fireflies, and electrochemiluminescent reactions involving electrical current. Forensic scientists use the chemiluminescent reaction of luminol to detect traces of blood at crime scenes by spraying a mixture that causes a blue glow in the presence of iron from hemoglobin.
This document summarizes research on infrared electroluminescence from GeSn heterojunction diodes grown by molecular beam epitaxy. Specifically, it reports on p-n heterojunction diodes fabricated from boron-doped p-type GeSn layers containing 8% Sn grown on n-type Ge substrates. Electroluminescence was observed from these diodes with a peak emission at 0.57 eV (2.15 microns). The emission intensity increased with higher drive currents and lower device temperatures. Total emitted power from a single edge facet was measured to be 54 microwatts at an applied peak current of 100 mA at 100 K. These results suggest GeSn materials may be useful for practical light
Kinetic modelling of nitrate removal from aqueous solution during electrocoag...Alexander Decker
This document discusses a study that aimed to model nitrate removal from aqueous solutions using electrocoagulation. Experiments were conducted to treat a synthetic solution containing 150 mg/L of nitrate using iron electrodes under various conditions. Kinetic and adsorption models were tested to determine which best fit the nitrate removal data. The results showed pseudo-second order kinetics and the Freundlich isotherm provided the best fits. Nitrate removal efficiency increased with reaction time and current density.
Comparison of hormonal assay by ELISA , ELFA and ECLrijaa
The document discusses various methods for hormone measurement and immunoassay techniques. It explains that hormone assays are important for clinical diagnosis and treatment monitoring. While early methods like bioassay and chemical analysis had low sensitivity, radioimmunoassay (RIA) introduced in 1959 improved detection. However, due to health risks, safer alternatives were sought. Enzyme-linked immunosorbent assay (ELISA) was developed in the 1970s as a replacement for RIA using enzymes rather than radioisotopes. More recent techniques like chemiluminescence, fluorescence, and electrochemiluminescence provide adequate sensitivity without radioactivity. The document compares the principles and properties of various immunoassay methods.
Electrochemical synthesis, characterization and electrochemical behaviour of...Alexander Decker
This document summarizes the electrochemical synthesis and characterization of new conducting copolymers composed of 2-methoxyaniline and 2,3-dihydrothieno[3,4-b][1,4]dioxine-2-carboxylic acid. Four copolymers were prepared at different monomer feed concentrations and characterized using cyclic voltammetry and infrared spectroscopy. In situ conductivity measurements on the copolymers revealed two transitions in conductivity. Homopolymers and copolymers were also investigated using in situ conductivity measurements.
This document outlines a project to design and fabricate a cooling system using ferrofluids. Ferrofluids are magnetic liquids that can be controlled using magnetic fields. The project involves synthesizing an aqueous ferrofluid and designing a system with a test section, pump, temperature sensors, heater and sink. When a temperature gradient is applied with a magnetic field, thermomagnetic convection occurs in the ferrofluid due to differences in magnetic susceptibility, enhancing heat transfer for cooling applications. The system is designed to test this effect and optimize heat transfer performance using ferrofluids.
The document summarizes a biology lab report on the effects of light intensity on photosynthesis. It finds that increasing the distance between the light source and plant (decreasing light intensity) decreases the rate of photosynthesis, as measured by counting oxygen bubbles. Specifically, it finds that the highest number of oxygen bubbles (and rate of photosynthesis) occurred at 10 cm between light and plant, and the lowest number of bubbles occurred at 50 cm. A graph shows an inverse relationship between distance from light and rate of photosynthesis. The experiment supports the hypothesis that increased light intensity leads to more light absorption and a higher photosynthesis rate.
Microwave assisted reaction km komal wahane k3komalwahane
Microwave assisted organic reactions can occur using solvents, under solvent-free conditions on solid supports, or using neat reactants. Reactions see increased rates due to microwave dielectric heating causing molecular polarization and rotation, generating heat. Key advantages are rapid reactions, high purity products, improved yields, and wider usable temperature ranges. Challenges include sudden temperature increases potentially distorting molecules or making reactions hazardous, and difficulty controlling heat.
This document reviews the use of microwave heating in organic synthesis. It begins with a brief history of heating methods in chemistry and an introduction to microwave theory. Key points are that microwaves directly couple with polar molecules to efficiently and uniformly heat reaction mixtures from the inside. This enables faster reactions and new reactivity compared to conventional thermal heating. The document discusses potential "microwave effects" including selective heating and hotspots, though most rate increases are due to purely thermal effects. It also reviews common microwave processing techniques like solventless reactions and highlights recent applications of microwave heating in areas like transition metal catalysis and combinatorial synthesis.
Andrew Ellis et al., Physica B, 385-386, (2006), 514 - 516.Duncan Gordon
This study investigated the physical aging of a blend of deuterated and hydrogenated poly(ethylene terephthalate) (PET) using differential scanning calorimetry (DSC) and small-angle neutron scattering (SANS). DSC showed an endothermic peak developed during aging and increased with aging time, indicating an increase in enthalpy. SANS revealed the radius of gyration decreased during aging, suggesting a change in molecular conformation. However, no difference was observed between aged and de-aged samples by SANS. The study thus showed physical aging of PET leads to changes in enthalpy and molecular conformation over time.
Enhancement of Heat Transfer in Heat Pipes using Al2O3/Benzene Based Nano-coo...RSIS International
Nowadays, the world is experiencing many challenges in solving heat transfer issues in various engineering systems. However, limited approaches are available to solve such challenges. To increase heat transfer, many researchers found that the Nanofluid is one of the feasible coolant which increase the working efficiency of many engineering devices. Electronic equipment dissipates enormous amount of heat while in operation which directly affect the work efficiency. To increase the efficiency it is mandatory to remove the heat by using proper coolant. Hence, the heat pipes are employed in electronic devices to remove the heat. To enhance the heat transfer in heat pipe nano-coolants may be used. In this present work, thermophysical properties of different types of base fluids with Aluminium oxide (Al2O3) Nanoparticles have been investigated with different concentrations of Nanoparticles (1-5 % by volume) at 300K temperature. The effective thermal conductivity of Nanofluids is compared with the base fluid and the results show enhancement in thermal conductivity. The thermal conductivity of Nanofluid is increased up to 3% at 300K with 1 % by volume concentration of nanoparticles and 15% at 5% by volume of concentration as compared to Benzene (C6H6) base fluid.
Microwave assisted synthesis is a green chemistry approach that uses microwave irradiation to accelerate chemical reactions. It has several advantages over traditional heating methods, such as faster reaction times, higher product purity, and lower energy usage. Microwaves work by causing polarization and ionic conduction in polar solvents and reagents, quickly generating heat. Common applications include coupling reactions like Suzuki, Heck, and Negishi reactions. SiC microwave vessels are preferable to Pyrex as they absorb microwaves more efficiently and allow for better temperature control of exothermic reactions.
This document discusses microwave assisted synthesis. Microwaves directly heat materials through ionic conduction and dipolar polarization. Microwave heating is more homogeneous than conventional heating methods. It allows for faster reactions, higher yields, lower energy consumption, and the ability to perform solvent-free reactions. Common organic reactions that can be carried out via microwave irradiation include Diels-Alder, ester hydrolysis, and nucleophilic substitutions. Microwave systems have advanced to enable both laboratory and industrial scale organic synthesis.
A new technique to measure oxygen reduction kinetics underneath coatings using hydrogen permeation from the back side. Huge step towards characterising buried interface reactivity.
The project will focus on synthesis of hexagonal structured pure phases of compositions: BaM1/3Ti2/3O3-δ and BaM1/6Ti5/6O3-δ, where M= Sc, In and Fe via different methods such as Solid state sintering and wet chemical route. The ultimate goal is to finding structure – functionality relationships within these proton and mixed conducting systems. A substantial effort will focus on search for and fabrication of new materials although the main part of the work will concentrate on detailed structural characterisation (rietveld refinement), impedance spectroscopy, infrared spectroscopy and thermogravimetric analysis.
In this paper, the analysis of optically responsive microfibers with uniaxially ordered liquid crystal (LC) molecules at their cores is discussed. LC microfibers were electrospun from a solution of poly(vinyl pyrrolidone) (PVP) and N-(4-methoxybenzylidene)-4$-butylaniline (MBBA) using absolute alcohol as a solvent. Two parallel copper (Cu) collectors were used to obtain ordered fibers. The microfibers with oriented LC molecules were well fabricated at a voltage of 5 kV. A thermal-optical analysis revealed that the fibers were responsive to temperature. The rise of temperature from nematic to isotropic phase of LC decreased the LC intensity under a polarized optical microscope (POM).
Increasing Thermal Conductivity of a Heat Exchanger Using Copper Oxide Nano F...IJERA Editor
A Nano fluid is the evolving concept which is very rarely used in the many core industries. Nano fluids have
found a great application in heat exchangers by increasing the thermal conductivity. We have aimed to
increasing the heat transfer co-efficient by using copper oxide Nano fluid. The Nano particles are formed by
using precipitation method and their fluids are formed by adding surfactants to the base fluid. The comparative
study on the Heat exchanger is made by using the CuO Nano Fluid and Hot water. The analysis and the results
shows that the overall heat transfer rate increases when subjected to Nano Fluids. The ethylene glycol fluid used
along with copper oxide Nano fluid will offer resistance to fouling.
This document summarizes a study on the preparation and heat transfer properties of zinc oxide (ZnO) nanofluid. ZnO nanoparticles were synthesized using a chemical precipitation method and characterized. ZnO nanofluids were prepared by dispersing the nanoparticles in ethylene glycol and water mixtures with surfactants. The nanofluids showed improved heat absorption capacity of 30-40% compared to the base fluids alone. When tested as a heat bath during sonication, the ZnO nanofluid effectively reduced the temperature rise, demonstrating its potential for heat transfer applications.
Carbon-cuprous oxide composite nanoparticles
were chemically deposited on surface of thin glass tubes of spent
energy saving lamps for solar heat collection. Carbon was
obtained from fly ash of heavy oil incomplete combustion in
electric power stations. Impurities in the carbon were removed by
leaching with mineral acids. The mineral free-carbon was then
wet ground to have a submicron size. After filtration, it was
reacted with concentrated sulfuric/fuming nitric acid mixture on
cold for 3-4 days. Potassium chlorate was then added drop wise on
hot conditions to a carbon slurry followed by filtration.
Nanocarbon sample was mixed with 5% by weight PVA to help
adhesion to the glass surface. Carbon so deposited was doped with
copper nitrate solution. After dryness, the carbon/copper nitrate
film was dipped in hydrazine hydrate to form cuprous oxide -
carbon composite, It was then roasted at 380-400 °C A heat
collector testing assembly was constructed of 5 glass coils
connected in series with a total surface area of 1250 cm2
. Heat
collection was estimated by water flowing in the glass coils that
are coated with the carbon/copper film,. Parameters affecting the
solar collection efficiency such as time of exposure and mass flow
rate of the water were studied. Results revealed that the prepared
glass coil has proven successful energy collector for solar heat.
Vapor Deposition of Semiconducting Phosphorus Allotropes into TiO2 Nanotube A...Pawan Kumar
The document describes the experimental methods used to synthesize and characterize hybrid fibrous red P@TiO2 and black P@TiO2 nanotube membrane materials for photoelectrocatalytic water splitting. TiO2 nanotube membranes were fabricated by anodization and then phosphorus allotropes were deposited via chemical vapor deposition. Characterization techniques included powder XRD, SEM/EDS, STEM/EDS, Raman spectroscopy, XPS, UPS, UV-Vis spectroscopy, KPFM, and gas chromatography to confirm the formation and properties of the hybrid materials. Structural analysis by XRD and Raman spectroscopy validated the incorporation of crystalline red and black phosphorus phases within the TiO2 nanotube membranes.
This document reports on a study investigating the free radical reaction between alkanes and carbon tetrachloride in solution. Product studies and kinetic electron paramagnetic resonance methods were used. The following key points are made:
1) Trichloromethyl radicals abstracted hydrogen from simple alkanes like cyclopentane and cyclohexane with rate constants of around 60 M-1s-1 in solution, in good agreement with gas phase data.
2) However, rate constants for chlorine abstraction by alkyl radicals from carbon tetrachloride were around 104 M-1s-1 in solution, around two orders of magnitude higher than in the gas phase.
3) Possibilities for this effect
How Tube 3 Changed Colors Into An Orange-BrownLisa Olive
In this experiment, the temperature change of water and different metal samples (aluminum, lead, and iron) were measured to calculate the specific heat of the metals. The metal samples were first heated, then added to water in a calorimeter. The maximum temperature change of the water was recorded. Using the mass of the metal sample, the temperature change of the metal and water, and the known specific heat of water, the specific heat of each metal was calculated using the equation q = m(SH)ΔT.
This document summarizes a study that developed a new hybrid electrocatalyst for oxygen evolution reaction (OER) by anchoring cobalt oxide (Co3O4) nanoparticles onto titanium carbide (Ti3C2) MXene nanosheets. The Co3O4/MXene hybrid (denoted CM) was synthesized using a solvothermal method. Characterization showed uniform distribution of small Co3O4 nanoparticles on MXene nanosheets. Electrochemical tests found the CM catalyst achieved overpotential of 300 mV at 10 mA/cm2 for OER, which was lower than Co3O4 or MXene alone. The enhanced performance was attributed to strong interactions and charge transfer between
Examination of methods to determine free-ion diffusivity and number density f...Weston Bell
This document summarizes a study that critically examines methods for determining free ion diffusivity and number density from analysis of electrode polarization. It shows that the commonly used Macdonald-Trukhan model of electrode polarization analysis fails to provide reasonable values at high salt concentrations. An empirical correction is proposed but caution is warranted as there is no solid theoretical justification. A variety of electrolyte materials, including polymer electrolytes, aqueous and nonaqueous solutions, and ionic liquids, were examined using dielectric spectroscopy and the results were compared to pulsed-field gradient NMR measurements.
This document summarizes a study on the inhibition of human alkaline phosphatases by vanadate. The key findings are:
1) Vanadate (orthovanadate) was found to be a potent competitive inhibitor of purified alkaline phosphatase from human liver, intestine and kidney, with a Ki of less than 1 microM.
2) The inhibitory effect of vanadate was reversed and full enzymatic activity was restored in the presence of 1mM adrenaline.
3) Phosphate and vanadate were found to compete for the same binding site on the enzyme.
Surfactant-assisted Hydrothermal Synthesis of Ceria-Zirconia Nanostructured M...IOSR Journals
CeO2–ZrO2 oxides were prepared by the surfactant-templated method using cetyl trimethyl ammonium bromide (CTAB) as template and modified with chromium nitrate. These were characterized by XRD, FT-IR, TEM, SEM, BET and TPD-CO2. The XRD data showed that as prepared CeO2-ZrO2 powder particles have single phase cubic fluorite structure. HRTEM shows mesoscopic ordering. Average particle size is 12-13 nm as calculated from particle histogram. The nitrogen adsorption/desorption isotherm were classified to be type IV isotherm, typical of mesoporous material. The presence of uni-modal mesopores are confirmed by the pore size distribution which shows pore distribution at around 60 A°. Catalytic activity was studied towards liquid-phase oxidation of benzene.
Research Abstract Submitted to Biomedical Engineering SocietyKalen Hall
The document describes research into using plasmonic heating from gold nanoparticles to stimulate neurons and cardiomyocytes as a potential alternative to electrical stimulation. The researchers fabricated gold nanoelectrodes by coating glass micropipettes with gold nanoparticles. They developed a method to indirectly measure temperature changes at the nanoelectrode surface using resistance measurements. Modeling of temperature distributions for single nanoparticles and nanoparticle arrays is also being conducted and compared to experimental data. Preliminary results showed local temperature increases exceeding 25 degrees could be achieved with high laser powers, demonstrating the potential of this stimulation approach.
This document summarizes a study on the irradiation-induced nanostructuring of Cu-TiB2 thin films with krypton ions. Room temperature irradiation led to the precipitation of ~4 nm cubic TiB nanoparticles, while irradiation at 650°C resulted in ~5 nm hexagonal TiB2 precipitates. The precipitate size and density (~2-3 × 1023 m-3) remained unchanged with increased dose from 1 × 1016 to 3 × 1016 ions/cm2 at 650°C, indicating a stable nanostructure formed. No extended defects were detected even at the highest dose, suggesting this nanostructuring imparts high radiation resistance.
Electrochemical Behavior of L-Tyrosine at Poly (Dicyclomine Hydrochloride) Fi...paperpublications3
Abstract: An electrochemical method for the determination of L-Tyrosine (LTY) using a dicyclomine hydrochloride (DICY) polymer film modified carbon paste electrode. The surface morphology of poly (DICY) modified carbon paste electrode was characterized by SEM. The modified electrode showed excellent electro catalytic activity towards the oxidation of LTY in 0.1 M phosphate buffer solution of pH 6.5. The effect of pH, concentration and scan rate were studied at the bare carbon paste electrode and poly (DICY) modified carbon paste electrode were investigated. Increase of LTY concentration shows linear increase in oxidation peak current. The linear relationship was obtained between the anodic peak current (Ipa) and concentration LTY in range 2×10-5 M to 1×10-3 M with correlation coefficient of 0.9984. The low detection limit (LOD) and low quantification limit (LOQ) of LTY were detected. The cyclic voltammetric studies indicated that the oxidation of LTY at the modified electrode surface was irreversible; adsorption controlled and undergoes a one electron transfer process at the poly (DICY) film modified carbon paste electrode. The modified electrode showed high sensitivity, detection limit, high reproducibility, easy preparation and regeneration of the electrode surface.
The document analyzes the generation of reactive oxygen species (ROS) from magnetic nanoparticles exposed to an alternating magnetic field and its role in intracellular hyperthermia. Key findings include:
1) Exposure to an AMF increased ROS production kinetics from nanoparticles faster than theoretical predictions, indicating AMF exposure improves ROS generation.
2) In vitro assays found that as nanoparticle concentration increased, ROS generation and cell viability both decreased in colon cancer cells, though with large variability.
3) The hypotheses that AMF heating of nanoparticles increases ROS production through Fenton and Haber-Weiss reactions, contributing to the toxicity of intracellular hyperthermia, are explored.
Factors affecting the rate of a chemical reactionDenni Domingo
The document discusses factors that affect the rate of a chemical reaction, including concentration of reactants, temperature, surface area, and presence of catalysts. It describes experiments conducted to study the effect of these factors on the reaction of magnesium with hydrochloric acid, decomposition of hydrogen peroxide, and the reaction of iron with copper nitrate. The reaction rates were found to increase with increasing concentration and temperature, and increasing the surface area of solid reactants. A catalyst was also found to increase the rate of decomposition of hydrogen peroxide.
Lead sulfide (PbS) is a semiconductor with applications in photonics and optoelectronics. PbS nanostructures of different morphologies including flower dendrites, sheets, and rod-like structures were synthesized via hydrothermal methods. These nanostructures exhibited broad absorption spectra in the near-infrared region and photoluminescence emission around 0.6 eV. Capping the nanostructures' surfaces with organic ligands improved their optical properties by passivating surface defects. Films of PbS nanostructures embedded in a conducting polymer showed photoconductive behavior and potential for photodetector applications.
This document summarizes research on the photoelectrocatalytic degradation of Remazol Black B (RBB) dye using nanostructured tungsten oxide (WO3) film electrodes. Key findings include:
1) WO3 film electrodes were found to be better photoelectrocatalysts for degrading RBB dye than titanium dioxide (TiO2) electrodes or molybdenum oxide (MoO3) electrodes with similar surface roughness.
2) Kinetic measurements showed the degradation of RBB on WO3 followed a generalized Langmuir-Hinshelwood model with an overall rate constant of 1.1 × 10−9 mol cm−2s−1.
3
Chemical modification of lignocellulosic materials by irradiation with Nd-YAG...NabilMabrouk6
1) Nd-YAG laser pulses were used to irradiate samples of lignin, microcrystalline cellulose, and filter paper. Lignin experienced substantial weight loss and degradation upon irradiation, while cellulose samples were unaffected.
2) Irradiation reduced the molecular weight and narrowed the molecular weight distribution of lignin. Smaller lignin fragments with increased phenolic hydroxyl content were produced.
3) Laser treatment provided a simple way to modify lignin properties without using chemical reagents. This technique could allow production of lignin samples with uniform characteristics.
Similar to Accelerated generation of free radicals by iron oxide nanoparticles in the presence of an alternating magnetic field (20)