The document discusses methods for calculating the Debye temperature from experimental data for mixed Na x K 1βx Cl crystals grown from aqueous solution. It describes growing 14 crystals with different compositions and doping some with ZnS. The Debye temperature was calculated using four methods: 1) from melting point data, 2) from Debye-Waller factor measurements from X-ray diffraction, 3) from microhardness values, and 4) from the Kopp-Neumann relation. The results from the first three methods were compared to the Kopp-Neumann relation to assess the accuracy of the different calculation techniques.
Lattice Parameters and Debye Temperature of Naclx Nabry-X Kcl1-Y Ternary Mixe...IOSR Journals
Β
Mixed crystals of alkali halides find applications in optical, optoelectronics and electronic devices. In the present study the pure and mixed crystals of NaClx NaBry-x KCl1-y were grown from the aqueous solution. The grown crystals were characterized by taking XRD, TG/DTA and Vickerβs hardness measurement. The Debye temperature is an important parameter of a solid. Several methods of evaluating Debye temperature are available. In the present study Debye temperature were calculated from the Debye- Waller factor, melting point and microhardness. The results were compared with the Kopp-Neumann relation.
11.a new mechanism of sodium zirconate formationAlexander Decker
Β
This document presents a new mechanism for forming sodium zirconate (Na2ZrO3) through the thermal decomposition of sodium acetate (CH3COONa) and zirconium(IV) acetylacetonate (Zr(C5H7O2)4). Thermogravimetric analysis showed the reaction occurs in three significant weight losses. Fourier transform infrared spectroscopy identified gases like CO2 and CO released during the reaction. X-ray diffraction confirmed the product was sodium zirconate. A kinetic study determined the activation energy, pre-exponential factor, and reaction order for each weight loss region using the Arrhenius equation. The proposed mechanism involves three reactions corresponding to the decomposition
This chapter of the textbook discusses electrochemistry concepts including:
- How electrode potentials and electrochemical cells are measured
- How standard electrode potentials are determined and used to predict spontaneity of reactions
- How the Nernst equation relates cell potential to concentration and allows calculation of potential for non-standard conditions
- Applications of concepts like batteries, corrosion, and electrolysis
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This chapter discusses thermochemistry and the concepts of heat, work, internal energy, enthalpy, and the first law of thermodynamics. It introduces terminology like system, surroundings, heat capacity, and heat of reaction. Methods for determining heats of reaction through calorimetry are presented, including bomb calorimetry and coffee cup calorimetry. The relationship between internal energy, enthalpy, and heat of reaction is explored. Standard states and standard enthalpy changes are defined. Hess's law for determining heats of reaction indirectly is introduced.
Solution Manual for A Problem-Solving Approach to Aquatic Chemistry β James J...HenningEnoksen
Β
https://www.book4me.xyz/solution-manual-aquatic-chemistry-jensen/
Solution Manual for A Problem-Solving Approach to Aquatic Chemistry
Author(s) :Β James N. Jensen
This solution manual include problems of these chapters from textbook: 2Ψ 3Ψ 4Ψ 6Ψ 7Ψ 8Ψ 11Ψ 12Ψ 13Ψ 15Ψ 16Ψ 18Ψ 19Ψ 21 and 22.
This chapter discusses chemical kinetics and reaction rates. It introduces concepts such as the rate of a reaction, methods of measuring reaction rates, and how concentration and temperature affect reaction rates. Specific reaction orders including zero-order, first-order, and second-order reactions are covered. Integrated rate laws are presented for determining reactant concentrations over time. The chapter also discusses theoretical models for chemical kinetics, including collision theory and activation energy, and how the Arrhenius equation describes the temperature dependence of reaction rates.
This document summarizes a study that measured the thermodynamic properties of Al1-xGaxN solid solutions at high temperatures using a solid-state electrochemical cell. The cell was used to determine the activity of GaN in Al1-xGaxN at 1100 K. Excess Gibbs free energy of mixing was then calculated. Results showed a mild tendency for ordering at specific compositions, along with predominantly positive deviation from ideal mixing behavior. Thermodynamic calculations also indicated instability below 410 K for compositions between 0.26β€xβ€0.5.
Lattice Parameters and Debye Temperature of Naclx Nabry-X Kcl1-Y Ternary Mixe...IOSR Journals
Β
Mixed crystals of alkali halides find applications in optical, optoelectronics and electronic devices. In the present study the pure and mixed crystals of NaClx NaBry-x KCl1-y were grown from the aqueous solution. The grown crystals were characterized by taking XRD, TG/DTA and Vickerβs hardness measurement. The Debye temperature is an important parameter of a solid. Several methods of evaluating Debye temperature are available. In the present study Debye temperature were calculated from the Debye- Waller factor, melting point and microhardness. The results were compared with the Kopp-Neumann relation.
11.a new mechanism of sodium zirconate formationAlexander Decker
Β
This document presents a new mechanism for forming sodium zirconate (Na2ZrO3) through the thermal decomposition of sodium acetate (CH3COONa) and zirconium(IV) acetylacetonate (Zr(C5H7O2)4). Thermogravimetric analysis showed the reaction occurs in three significant weight losses. Fourier transform infrared spectroscopy identified gases like CO2 and CO released during the reaction. X-ray diffraction confirmed the product was sodium zirconate. A kinetic study determined the activation energy, pre-exponential factor, and reaction order for each weight loss region using the Arrhenius equation. The proposed mechanism involves three reactions corresponding to the decomposition
This chapter of the textbook discusses electrochemistry concepts including:
- How electrode potentials and electrochemical cells are measured
- How standard electrode potentials are determined and used to predict spontaneity of reactions
- How the Nernst equation relates cell potential to concentration and allows calculation of potential for non-standard conditions
- Applications of concepts like batteries, corrosion, and electrolysis
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This chapter discusses thermochemistry and the concepts of heat, work, internal energy, enthalpy, and the first law of thermodynamics. It introduces terminology like system, surroundings, heat capacity, and heat of reaction. Methods for determining heats of reaction through calorimetry are presented, including bomb calorimetry and coffee cup calorimetry. The relationship between internal energy, enthalpy, and heat of reaction is explored. Standard states and standard enthalpy changes are defined. Hess's law for determining heats of reaction indirectly is introduced.
Solution Manual for A Problem-Solving Approach to Aquatic Chemistry β James J...HenningEnoksen
Β
https://www.book4me.xyz/solution-manual-aquatic-chemistry-jensen/
Solution Manual for A Problem-Solving Approach to Aquatic Chemistry
Author(s) :Β James N. Jensen
This solution manual include problems of these chapters from textbook: 2Ψ 3Ψ 4Ψ 6Ψ 7Ψ 8Ψ 11Ψ 12Ψ 13Ψ 15Ψ 16Ψ 18Ψ 19Ψ 21 and 22.
This chapter discusses chemical kinetics and reaction rates. It introduces concepts such as the rate of a reaction, methods of measuring reaction rates, and how concentration and temperature affect reaction rates. Specific reaction orders including zero-order, first-order, and second-order reactions are covered. Integrated rate laws are presented for determining reactant concentrations over time. The chapter also discusses theoretical models for chemical kinetics, including collision theory and activation energy, and how the Arrhenius equation describes the temperature dependence of reaction rates.
This document summarizes a study that measured the thermodynamic properties of Al1-xGaxN solid solutions at high temperatures using a solid-state electrochemical cell. The cell was used to determine the activity of GaN in Al1-xGaxN at 1100 K. Excess Gibbs free energy of mixing was then calculated. Results showed a mild tendency for ordering at specific compositions, along with predominantly positive deviation from ideal mixing behavior. Thermodynamic calculations also indicated instability below 410 K for compositions between 0.26β€xβ€0.5.
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
International Journal of Engineering Research and Applications (IJERA) aims to cover the latest outstanding developments in the field of all Engineering Technologies & science.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
This document contains an unsolved chemistry practice test from 2004 with 50 multiple choice questions covering various topics in chemistry including quantum numbers, atomic structure, chemical bonding, acid-base reactions, solutions, equilibrium, electrochemistry, and coordination compounds. The questions require selecting the best answer from four choices given for each problem.
This document summarizes Chapter 20 from the textbook "General Chemistry: Principles and Modern Applications" by Petrucci, Harwood, and Herring. The chapter discusses spontaneous change, entropy, free energy, and criteria for spontaneity. It defines key concepts like entropy, the second law of thermodynamics, standard free energy change, and how free energy relates to chemical equilibrium. The chapter also examines how these principles apply to temperature dependence of equilibrium constants and coupled chemical reactions.
This document contains 116 multiple choice questions from an AIEEE exam covering topics in chemistry and physics. The questions test knowledge of quantum numbers, atomic structure, chemical bonding, thermodynamics, equilibrium, electrochemistry, and other core concepts. Sample questions include identifying the correct set of quantum numbers for an electron in the 4f orbital and determining the standard reduction potential of a cell involving a one electron change reaction.
This document summarizes a student group's chemistry experiment on the effect of temperature on the solubility of potassium nitrate. The group used a Stella dynamic model to predict that solubility would increase exponentially with temperature. They conducted trials dissolving potassium nitrate in water at 0Β°C, 25Β°C and 60Β°C, collecting data from 15 total trials at each temperature. Their results showed solubility increased as temperature increased, supporting their hypothesis. However, their 60Β°C data was lower than predicted, possibly due to cooling from room temperature. Overall, their precise data matched other research, though other large data sets showed more variability.
Low-temperature thermoelectric and magnetic characteristics of Ca2.9Bi0.1Co4-...Chih-Ju Lin
Β
The document summarizes the effects of iron doping on the low-temperature thermoelectric and magnetic properties of Ca2.9Bi0.1Co4-xFexO9+d samples where x ranges from 0 to 0.10. X-ray diffraction analysis showed all samples were single phase. Electrical resistivity decreased with increasing iron content due to higher hole carrier concentration. Thermopower was positive over the entire temperature range indicating hole carriers. The highest dimensionless figure of merit of 0.056 at 300K was found for the x=0.10 sample, which also had the lowest resistivity, thermopower and thermal conductivity among the samples. Magnetic measurements showed all samples exhibited a low-spin state
This document is a slide presentation on chapter 3 of the textbook "General Chemistry: Principles and Modern Applications" by Petrucci, Harwood, and Herring. The chapter discusses chemical compounds, including molecular and ionic compounds, molecular mass, composition, oxidation states, naming conventions, and focuses on mass spectrometry. It provides examples of calculating empirical formulas and assigning oxidation states, and discusses isomers, functional groups of carboxylic acids and alcohols.
First Year Chemistry_Full Book Exercise Mcqs SolvedMalik Xufyan
Β
- The document contains sample multiple choice questions from the 1st Year Chemistry textbook covering topics like basic concepts, experimental techniques, gases, liquids and solids, atomic structure, and chemical bonding.
- Questions are provided from chapters 1-6 of the textbook along with four answer options for each question.
- The purpose of the document is to provide a full book of sample exercise MCQs for 1st Year Chemistry exams for all Punjab boards in Pakistan.
This document provides an outline for lessons on the topic of chemical equilibrium. It includes:
1) Four lessons that cover investigating equilibrium reactions, determining equilibrium constants (Kc), using the ICE method to solve equilibrium problems, and the relationship between Gibbs free energy (ΞG) and equilibrium.
2) Details of activities and assessments at various levels for each lesson, including determining Kc values, using ICE to find equilibrium concentrations, defining Gibbs free energy, and relating ΞG to Kc.
3) Examples of ICE questions to work through in class covering determining Kc from concentrations, finding concentrations from Kc, and cases where Kc is very small.
4) A discussion of
This document contains questions about thermodynamics and electronic structure. Regarding thermodynamics, questions cover topics like exothermic and endothermic phase changes, standard enthalpies of formation, entropy, Gibbs free energy, and thermochemical equations. Regarding electronic structure, questions cover topics like electron configurations, quantum numbers, diamagnetism, isoelectronic species, and periodic trends.
This document contains 15 multiple choice questions about thermodynamics and 5 multiple choice questions about electronic structure. The thermodynamics questions cover topics like phase changes, entropy, Gibbs free energy, enthalpy of reaction, and thermochemistry calculations. The electronic structure questions cover topics like electron configuration, quantum numbers, and isoelectronic species.
This document contains a student textbook passage and accompanying questions about quantities in chemical reactions and the mole concept. It includes definitions of key terms like the mole, molar mass, atomic mass and molecular mass. Sample questions assess understanding of calculating moles from mass and vice versa, and relating particles, moles and masses in chemical formulas. The passage emphasizes that the mole is a practical unit for measuring substances at the macroscopic scale that relates to particles at the microscopic scale.
This document contains 50 multiple choice questions from a 1st year chemistry notes chapter on basic concepts. The questions cover topics like atoms, molecules, ions, isotopes, relative atomic mass, stoichiometry, moles, the mole concept, and gas laws. An answer key is provided at the end with the correct response for each question.
This document provides information about chemical reactions, including:
- Chemical reactions involve changing one or more substances into new substances.
- Signs of chemical reactions include gas formation, solid formation, energy release, color changes, and the formation of new substances with different properties.
- There are different types of chemical reactions including synthesis, decomposition, single-displacement, and double-displacement reactions.
- Chemical equations are used to represent chemical reactions and must be balanced by adding coefficients to show that the same number of atoms are on each side.
This document is a slide presentation from a chapter in a general chemistry textbook. The chapter covers fundamental topics in chemistry including the properties and states of matter, measurement systems, and dimensional analysis. It discusses physical and chemical properties, classification of substances and mixtures, separation techniques, units and conversions, temperature scales, density, and uncertainties in measurement.
This document provides an overview of key concepts in chemistry including:
- Matter is anything that has mass and occupies space. Common types of matter include elements, compounds, and mixtures.
- Energy is the ability to do work or transfer heat and exists in various forms like chemical, thermal, nuclear, and electrical.
- Chemical and physical properties can be used to describe matter. Chemical properties involve changes in composition while physical properties can be observed without composition changes.
- Important concepts in chemistry include the laws of conservation of mass and energy, the relationship between matter and energy described by Einstein's equation E=mc2, and endothermic and exothermic reactions. Measurements involve units, significant figures, and conversions between
The researchers were attempting to grow high quality single crystals of the ternary dichalcogenide NbIrTe4 using two different growth methods: chemical vapor transport and a reaction using molten tellurium. Preliminary results using chemical vapor transport were inconsistent, yielding powders of various binary phases rather than large NbIrTe4 crystals. Using a reaction with molten tellurium in contact with Nb and Ir powders produced NbIrTe4 crystals at the interface, confirming the layered growth technique is more promising. Moving forward, the researchers will optimize this new technique for growing larger NbIrTe4 crystals and also explore synthesizing the ungrown compound ZrIrTe4.
Performance Comparison of K-means Codebook Optimization using different Clust...IOSR Journals
Β
The document compares the performance of codebook optimization using different clustering techniques with the K-means algorithm. It first describes vector quantization as a lossy image compression technique that relies on an optimal codebook. It then discusses using K-means clustering to iteratively optimize the codebook by minimizing the mean square error. The document generates codebooks using LBG, KPE, KFCG, and random selection, and applies K-means optimization to each. It finds that KFCG results in the lowest mean square error, indicating it produces a codebook closest to the optimal solution when used with K-means optimization.
This document discusses technology trends and questions for a tech industry professional. It asks about the technology ecosystem they work in, how mobile their work is, hot technologies to consider, how they keep up with changes, how they decide to buy devices, the importance of browsers, their internet presence, whether they are paperless, and their technology plan.
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
International Journal of Engineering Research and Applications (IJERA) aims to cover the latest outstanding developments in the field of all Engineering Technologies & science.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
This document contains an unsolved chemistry practice test from 2004 with 50 multiple choice questions covering various topics in chemistry including quantum numbers, atomic structure, chemical bonding, acid-base reactions, solutions, equilibrium, electrochemistry, and coordination compounds. The questions require selecting the best answer from four choices given for each problem.
This document summarizes Chapter 20 from the textbook "General Chemistry: Principles and Modern Applications" by Petrucci, Harwood, and Herring. The chapter discusses spontaneous change, entropy, free energy, and criteria for spontaneity. It defines key concepts like entropy, the second law of thermodynamics, standard free energy change, and how free energy relates to chemical equilibrium. The chapter also examines how these principles apply to temperature dependence of equilibrium constants and coupled chemical reactions.
This document contains 116 multiple choice questions from an AIEEE exam covering topics in chemistry and physics. The questions test knowledge of quantum numbers, atomic structure, chemical bonding, thermodynamics, equilibrium, electrochemistry, and other core concepts. Sample questions include identifying the correct set of quantum numbers for an electron in the 4f orbital and determining the standard reduction potential of a cell involving a one electron change reaction.
This document summarizes a student group's chemistry experiment on the effect of temperature on the solubility of potassium nitrate. The group used a Stella dynamic model to predict that solubility would increase exponentially with temperature. They conducted trials dissolving potassium nitrate in water at 0Β°C, 25Β°C and 60Β°C, collecting data from 15 total trials at each temperature. Their results showed solubility increased as temperature increased, supporting their hypothesis. However, their 60Β°C data was lower than predicted, possibly due to cooling from room temperature. Overall, their precise data matched other research, though other large data sets showed more variability.
Low-temperature thermoelectric and magnetic characteristics of Ca2.9Bi0.1Co4-...Chih-Ju Lin
Β
The document summarizes the effects of iron doping on the low-temperature thermoelectric and magnetic properties of Ca2.9Bi0.1Co4-xFexO9+d samples where x ranges from 0 to 0.10. X-ray diffraction analysis showed all samples were single phase. Electrical resistivity decreased with increasing iron content due to higher hole carrier concentration. Thermopower was positive over the entire temperature range indicating hole carriers. The highest dimensionless figure of merit of 0.056 at 300K was found for the x=0.10 sample, which also had the lowest resistivity, thermopower and thermal conductivity among the samples. Magnetic measurements showed all samples exhibited a low-spin state
This document is a slide presentation on chapter 3 of the textbook "General Chemistry: Principles and Modern Applications" by Petrucci, Harwood, and Herring. The chapter discusses chemical compounds, including molecular and ionic compounds, molecular mass, composition, oxidation states, naming conventions, and focuses on mass spectrometry. It provides examples of calculating empirical formulas and assigning oxidation states, and discusses isomers, functional groups of carboxylic acids and alcohols.
First Year Chemistry_Full Book Exercise Mcqs SolvedMalik Xufyan
Β
- The document contains sample multiple choice questions from the 1st Year Chemistry textbook covering topics like basic concepts, experimental techniques, gases, liquids and solids, atomic structure, and chemical bonding.
- Questions are provided from chapters 1-6 of the textbook along with four answer options for each question.
- The purpose of the document is to provide a full book of sample exercise MCQs for 1st Year Chemistry exams for all Punjab boards in Pakistan.
This document provides an outline for lessons on the topic of chemical equilibrium. It includes:
1) Four lessons that cover investigating equilibrium reactions, determining equilibrium constants (Kc), using the ICE method to solve equilibrium problems, and the relationship between Gibbs free energy (ΞG) and equilibrium.
2) Details of activities and assessments at various levels for each lesson, including determining Kc values, using ICE to find equilibrium concentrations, defining Gibbs free energy, and relating ΞG to Kc.
3) Examples of ICE questions to work through in class covering determining Kc from concentrations, finding concentrations from Kc, and cases where Kc is very small.
4) A discussion of
This document contains questions about thermodynamics and electronic structure. Regarding thermodynamics, questions cover topics like exothermic and endothermic phase changes, standard enthalpies of formation, entropy, Gibbs free energy, and thermochemical equations. Regarding electronic structure, questions cover topics like electron configurations, quantum numbers, diamagnetism, isoelectronic species, and periodic trends.
This document contains 15 multiple choice questions about thermodynamics and 5 multiple choice questions about electronic structure. The thermodynamics questions cover topics like phase changes, entropy, Gibbs free energy, enthalpy of reaction, and thermochemistry calculations. The electronic structure questions cover topics like electron configuration, quantum numbers, and isoelectronic species.
This document contains a student textbook passage and accompanying questions about quantities in chemical reactions and the mole concept. It includes definitions of key terms like the mole, molar mass, atomic mass and molecular mass. Sample questions assess understanding of calculating moles from mass and vice versa, and relating particles, moles and masses in chemical formulas. The passage emphasizes that the mole is a practical unit for measuring substances at the macroscopic scale that relates to particles at the microscopic scale.
This document contains 50 multiple choice questions from a 1st year chemistry notes chapter on basic concepts. The questions cover topics like atoms, molecules, ions, isotopes, relative atomic mass, stoichiometry, moles, the mole concept, and gas laws. An answer key is provided at the end with the correct response for each question.
This document provides information about chemical reactions, including:
- Chemical reactions involve changing one or more substances into new substances.
- Signs of chemical reactions include gas formation, solid formation, energy release, color changes, and the formation of new substances with different properties.
- There are different types of chemical reactions including synthesis, decomposition, single-displacement, and double-displacement reactions.
- Chemical equations are used to represent chemical reactions and must be balanced by adding coefficients to show that the same number of atoms are on each side.
This document is a slide presentation from a chapter in a general chemistry textbook. The chapter covers fundamental topics in chemistry including the properties and states of matter, measurement systems, and dimensional analysis. It discusses physical and chemical properties, classification of substances and mixtures, separation techniques, units and conversions, temperature scales, density, and uncertainties in measurement.
This document provides an overview of key concepts in chemistry including:
- Matter is anything that has mass and occupies space. Common types of matter include elements, compounds, and mixtures.
- Energy is the ability to do work or transfer heat and exists in various forms like chemical, thermal, nuclear, and electrical.
- Chemical and physical properties can be used to describe matter. Chemical properties involve changes in composition while physical properties can be observed without composition changes.
- Important concepts in chemistry include the laws of conservation of mass and energy, the relationship between matter and energy described by Einstein's equation E=mc2, and endothermic and exothermic reactions. Measurements involve units, significant figures, and conversions between
The researchers were attempting to grow high quality single crystals of the ternary dichalcogenide NbIrTe4 using two different growth methods: chemical vapor transport and a reaction using molten tellurium. Preliminary results using chemical vapor transport were inconsistent, yielding powders of various binary phases rather than large NbIrTe4 crystals. Using a reaction with molten tellurium in contact with Nb and Ir powders produced NbIrTe4 crystals at the interface, confirming the layered growth technique is more promising. Moving forward, the researchers will optimize this new technique for growing larger NbIrTe4 crystals and also explore synthesizing the ungrown compound ZrIrTe4.
Performance Comparison of K-means Codebook Optimization using different Clust...IOSR Journals
Β
The document compares the performance of codebook optimization using different clustering techniques with the K-means algorithm. It first describes vector quantization as a lossy image compression technique that relies on an optimal codebook. It then discusses using K-means clustering to iteratively optimize the codebook by minimizing the mean square error. The document generates codebooks using LBG, KPE, KFCG, and random selection, and applies K-means optimization to each. It finds that KFCG results in the lowest mean square error, indicating it produces a codebook closest to the optimal solution when used with K-means optimization.
This document discusses technology trends and questions for a tech industry professional. It asks about the technology ecosystem they work in, how mobile their work is, hot technologies to consider, how they keep up with changes, how they decide to buy devices, the importance of browsers, their internet presence, whether they are paperless, and their technology plan.
A Tailored Anti-Forensic Approach for Bitmap Compression in Medical ImagesIOSR Journals
Β
This document proposes a new anti-forensic technique to hide evidence of compression history and manipulations in medical bitmap images. Existing methods for identifying compression history include JPEG detection and quantization table estimation, which analyze image transform coefficients for variations and blocking artifacts from compression. The proposed method indicates that properly adding noise to an image's transform coefficients can eliminate quantization artifacts and compression indicators, making the image appear as if it had never been compressed. This anti-forensic technique aims to cover up a medical image's processing history and enable undetectable image tampering.
Navigation Cost Modeling Based On OntologyIOSR Journals
Β
This document discusses a navigation cost modeling technique based on ontology for effective navigation of query results from large datasets. It presents an approach that uses concept hierarchies built from annotated data to categorize results and reduce the number displayed to users. An initial navigation tree is constructed from the concept hierarchies and optimized by removing empty nodes. EdgeCuts are then used to expand portions of the tree to minimize navigation cost for users. The proposed technique aims to provide more efficient navigation of query results than existing systems through categorization, ranking and modeling of navigation costs.
Horizontal Aggregations in SQL to Prepare Data Sets for Data Mining AnalysisIOSR Journals
Β
This document discusses techniques for performing horizontal aggregations in SQL to prepare data sets for data mining analysis. It presents three methods for horizontal aggregation using SQL - SPJ, PIVOT, and CASE. SPJ performs aggregation through joining tables containing vertical aggregations. PIVOT uses the SQL PIVOT operator to transpose results. CASE extends the SQL CASE construct. The methods were implemented in a prototype application and experiments showed the methods can generate horizontally formatted data sets suitable for data mining.
K-NN Classifier Performs Better Than K-Means Clustering in Missing Value Imp...IOSR Journals
Β
This document compares the performance of K-means clustering and K-nearest neighbor (K-NN) classification for imputing missing values. It finds that K-NN performs better than K-means clustering in terms of accuracy when imputing missing values at rates from 2% to 20%. The document simulates datasets with various missing value rates, uses each method to group the data and impute missing values via mean substitution, and compares the results to the original complete dataset to calculate accuracy. K-NN achieved an average accuracy of 67% compared to 62% for K-means clustering across the different missing value rates tested.
This document summarizes a grid-connected photovoltaic power system that uses a boost-half-bridge converter. The system aims to efficiently transfer power from a solar PV array to the electric grid. It consists of two main stages - a boost-half-bridge DC-DC converter that steps up the low-voltage solar output, and a full-bridge inverter that feeds a sinusoidal current into the grid via an LCL filter. The boost-half-bridge converter provides galvanic isolation and a high step-up ratio with minimal components. Maximum power point tracking is performed to optimize solar energy extraction while limiting transient effects on efficiency.
Design And Development of A Plug-In Type Wireless Data Logger for Energy Meas...IOSR Journals
Β
This document describes the design and development of a plug-in type wireless data logger for energy measurement. The data logger is designed to accurately measure energy, voltage, current, and instantaneous power in real time for single-phase applications. It consists of hardware modules for energy measurement, data transmission, and reception. The energy measurement module uses a CS5460A chip to measure parameters. Data is transmitted wirelessly via Bluetooth and received on a computer interface. The system aims to provide low-cost real-time energy monitoring for appliances to encourage efficient energy usage.
Effects of SIP in Interoperable LMR/Cellular Heterogeneous Mobile Wireless N...IOSR Journals
Β
This document discusses the effects of using Session Initiation Protocol (SIP) for handoffs between Land Mobile Radio (LMR) networks and cellular networks in a heterogeneous wireless network environment for disaster responder communications. It first provides background on LMR and cellular networks and their differences. It then discusses previous work on vertical handoff algorithms and decision mechanisms. Next, it explains how traditional SIP uses a "break-before-make" approach to reduce handoff delay but does not achieve seamless handoff. Finally, it notes that radio resource utilization must also be considered in the design of a disaster responder communication network due to the challenges of supporting multimedia applications.
This document outlines the content of a biostatistics course. It introduces statistics, defining it as the collection, organization, analysis and interpretation of data to draw conclusions. It discusses descriptive and inferential statistics. It also covers topics like data classification, levels of measurement, sampling techniques and methods of data collection that will be taught in the course's first four chapters. These chapters will address central tendency, variation, frequency distributions, and range.
Este documento presenta informaciΓ³n sobre causas y efectos de los sismos, asΓ como medidas para calificarlos. Explica que los sismos ocurren debido a la liberaciΓ³n de energΓa en el interior de la tierra, especialmente cuando placas tectΓ³nicas chocan. Se miden la intensidad, basada en daΓ±os observados, y la magnitud, que calcula la energΓa liberada. Un sismo moderado puede daΓ±ar viviendas mal diseΓ±adas o construidas.
The document discusses using DNA sequences to encrypt data uniquely for each individual. It proposes assigning each of the four DNA components (adenine, thymine, guanine, cytosine) a fixed algorithm. The encryption sequence would then be based on the individual's unique DNA component sequence. This could reduce complex algorithms and keys needed while making the encrypted data difficult to decrypt even if keys are identified, since the plain text could not be retrieved without knowing the exact DNA sequence. The methodology and algorithms considered for this approach are also discussed.
Implementation of Semantic Analysis Using Domain OntologyIOSR Journals
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The document describes a semantic analysis system that analyzes feedback from an organization using domain ontology. The system first collects feedback data from students in an unstructured format. It then preprocesses the feedback using part-of-speech tagging to extract meaningful information. The system architecture includes preprocessing the feedback, matching entities in the feedback to an organization ontology using Jaccard similarity, and generating a summarized analysis of the feedback based on the ontology entities. The goal is to group related words and phrases expressed by students under the same entity to produce a meaningful summary for the organization.
1) The document proposes using multipath TCP (MPTCP) as a more effective way to manage data center networks compared to single path TCP. MPTCP can utilize available bandwidth across multiple paths simultaneously, improving throughput and fairness.
2) Large-scale flow-level simulations show that MPTCP achieves close to full utilization of FatTree, VL2, and BCube network topologies, outperforming randomized load balancing with single path TCP, which struggles to fully utilize the networks. The minimum number of MPTCP subflows needed does not significantly increase with larger network sizes.
3) Packet-level simulations and experiments on a small testbed validate that MPTCP effectively utilizes multiple paths in practice and improves performance over single
Formal Modeling and Verification of Trusted OLSR Protocol Using I-SPIN Model...IOSR Journals
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The document describes formal modeling and verification of the Trusted Optimized Link State Routing Protocol (TOLSR) using the I-SPIN model checker and PROMELA language. It summarizes that the basic OLSR protocol has vulnerabilities to attacks from malicious nodes. To address this, a trust-based framework is proposed where trust values between nodes are incorporated into the protocol's functioning. The TOLSR protocol is formally modeled and verified in PROMELA at different levels of complexity. The model checking results show the TOLSR protocol specifications are validated and memory usage increases with complexity, demonstrating the effectiveness of formal modeling for developing secure and reliable ad hoc network routing protocols.
IOSR Journal of Electronics and Communication Engineering(IOSR-JECE) is an open access international journal that provides rapid publication (within a month) of articles in all areas of electronics and communication engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electronics and communication engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Using Data-Mining Technique for Census Analysis to Give Geo-Spatial Distribut...IOSR Journals
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This document discusses using data mining techniques to analyze census data and provide geographic distributions of populations in Nigeria. It specifically uses a decision tree algorithm to predict attributes of populations like number of males/females, employment status, etc. from census databases. It then integrates these predictions with a geographic information system to display the geo-spatial distributions on maps. The results showed this approach was able to successfully extract predictive attributes from census data and provide geographic distributions to help inform business and government decisions. It recommends future work address overfitting issues and better handling of continuous attributes.
Thermoelectric Power Studies of Ni-Co Nano Ferrites Synthesized By Citrate-Ge...IOSR Journals
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This document reports on a study of the thermoelectric power of nickel-cobalt nanoferrites with the chemical formula Ni1-xCoxFe2O4 (where x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) synthesized using the citrate-gel auto combustion method. X-ray diffraction analysis confirmed the formation of a single cubic spinel phase without impurities. Lattice parameters increased with increasing cobalt content due to the larger ionic radius of Co2+ ions compared to Ni2+ ions. Seebeck coefficient measurements from 320K to above the Curie temperature showed that the materials behaved as n-type semiconductors and the
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Pairing and Symmetries in Nuclear MatterAlex Quadros
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This document discusses nuclear pairing phenomena using a Dirac-Hartree-Fock-Bogolyubov approach. Key findings include:
1) Nuclear pairing occurs when nucleons within nuclei or neutron stars form strongly correlated pairs at short distances. This includes standard proton-proton and neutron-neutron pairing.
2) The Dirac-Hartree-Fock-Bogolyubov approach provides a relativistic description of nuclear matter using mean fields and particle-hole and particle-particle transformations.
3) Symmetries of the Dirac-Hartree-Fock-Bogolyubov Hamiltonian, including isospin symmetry, allow certain unitary transformations that can diagonalize the Hamiltonian.
This document reports on the synthesis and structural characterization of Ni1βxCdxFe2O4 materials. Key points:
- Ni1βxCdxFe2O4 materials were synthesized using an auto-combustion technique, producing nanoparticles between 29-33 nm.
- X-ray diffraction analysis confirmed the formation of a single cubic spinel phase structure with increasing lattice parameter with higher Cd content.
- Fourier transform infrared spectroscopy showed absorption bands in the 400-700 cmβ1 region.
- Density functional theory calculations using the ATK-VNL code verified the experimental structural parameters and showed the materials have metallic electronic behavior.
This document reports on a conductometric study of several 1-1 electrolytes (potassium thiocyanate, ammonium thiocyanate, sodium nitrate, ammonium nitrate) in the solvent 2-ethoxyethanol. Precise conductivity measurements were made at various temperatures. The data were analyzed using the 1978 Fuoss conductance equation to determine limiting molar conductivity, association constant, and cosphere diameter. Strong ion association was found for all electrolytes. The cations were substantially solvated by 2-ethoxyethanol while the anions had only weak interaction with the solvent molecules.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This document summarizes research on the synthesis and characterization of cadmium-substituted nickel ferrite (Ni1-xCdxFe2O4) powders prepared using an auto-combustion technique. X-ray diffraction analysis confirmed the formation of single-phase spinel structures for all compositions sintered at 1050Β°C. Lattice parameters increased linearly with increasing cadmium content due to the larger ionic radius of Cd2+. Bulk density decreased with higher cadmium concentration but increased with sintering temperature. FTIR analysis showed that absorption band positions shifted to lower wave numbers with cadmium substitution due to redistribution of Fe3+ ions between octahedral and tetrahedral sites.
This document provides an outline for lessons on the topics of energetics and thermochemistry. It includes lessons on lattice enthalpy determination using Born-Haber cycles and enthalpies of solution. It also covers entropy, Gibbs free energy, and calculating changes in these properties for chemical reactions. Sample practice problems and review questions are provided to help teach these concepts and allow students to check their understanding.
Hanle Effect Measurements of Spin Lifetime in Zn0.4Cd0.6Se Epilayers Grown on...Oleg Maksimov
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This document summarizes a study that used the Hanle effect to measure spin lifetimes in ZnCdSe epilayers grown on InP substrates with varying n-doping levels. Four samples were studied: three Zn0.4Cd0.6Se samples with carrier densities of 8.0Γ1016 cm-3, 4.3Γ1017 cm-3, and 1.1Γ1018 cm-3, as well as an undoped Zn0.5Cd0.5Se sample. Measurements showed that spin lifetime varied non-monotonically with carrier density, reaching a maximum of ~10.5 ns for the sample near the metal-insulator transition.
1. The study examines the high-pressure behavior of diopside using single-crystal X-ray diffraction and density functional theory calculations.
2. It finds that diopside transforms from a C2/c phase with 4-coordinated silicon to a P21/c phase with mixed 4- and 6-coordinated silicon at around 50 GPa, and then to a P21/c phase with 5- and 6-coordinated silicon at around 55 GPa.
3. Density functional theory calculations confirm the phase transitions and predict the existence of the higher pressure phase with 5-coordinated silicon.
This document summarizes research testing a model-guided approach to developing new thermoluminescent materials using yttrium aluminum garnet (YAG) doped with lanthanide elements produced via solution combustion synthesis. YAG doped with cerium, europium, terbium, and ytterbium was synthesized and characterized. Characterization showed that ytterbium acts as an electron trap in YAG:Ce,Yb and YAG:Tb,Yb, while cerium and terbium are the recombination centers. Europium acts as an electron trap in YAG:Ce,Eu and YAG:Tb,Eu, while cerium and terbium are the
Study the physical properties of some alloy materials and effect of gamma rad...Alexander Decker
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This document discusses a study on the physical properties of alloy materials containing tellurium, germanium, selenium, and arsenic. Specifically, it examines the effect of replacing selenium with tellurium in TexGe20Se(60-x)As20 thin films at concentrations of 0, 10, 15 and 20 atomic %. The key findings are:
1) Increasing the tellurium content decreases the average heat of atomization, cohesive energy, and optical band gap of the alloy materials.
2) Optical absorption measurements show the fundamental absorption edge decreases with higher tellurium content, indicating allowed direct transitions.
3) The decrease in optical band gap with increasing tellurium can be
A facile method to prepare CdO-Mn3O4 nanocompositeIOSR Journals
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CdO-Mn3O4 nanocomposite has been prepared by a simple solvothermal method using a domestic microwave oven. Cadmium acetate, manganese acetate and urea were used as the precursors and ethylene glycol as the solvent. The as-prepared sample was annealed for 1 hour in each case at different temperatures, viz. 100, 200 and 300Β°C. The as-prepared and annealed samples were characterized by X-ray diffraction and scanning electron microscopic analyses. Results indicate that annealing at 300Β°C is required to get the sample with high phase purity and homogeneity. The present study indicates that the method adopted can be considered as an economical and scalable one to prepare the proposed nanocomposite with reduced size, phase purity and homogeneity.
Mixed Ligand, Palladium(II) and Platinum(II) Complexes of Tertiary Diphosphin...Karwan Omer
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This document summarizes a study that synthesized and characterized mixed ligand palladium(II), platinum(II) complexes with tertiary diphosphine and S-1H benzo[d]imidazole-2-yl benzothioate ligands. The complexes were synthesized in two steps, first forming metal complexes with tertiary diphosphines, then adding the S-1H benzimidazole ligand. The complexes were characterized using techniques such as elemental analysis, infrared spectroscopy, UV-Vis spectroscopy, magnetic susceptibility, and X-ray crystallography. The results indicate the ligand bonds to the metal through the nitrogen atom and the complexes have square planar geometries.
This report contains the theory behind the algorithm to find the composition of air at temperatures 200-9000 K. A C++ program for the same is hosted at my profile on GitHub.com/kcavatar.
Structural and Dielectric Studies of Cerium Substituted Nickel Ferrite Nano P...theijes
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Cerium substituted Nickel ferrite nanoparticles with general formula NiCeXFe2-XO4 (x=0.0, 0.05, 0.1, 0.15) have been synthesized by using sol-gel method. The crystalline structure and grain size of these particles were analyzed by using XRD; the particle size ranged from 12.22nm to 17.60nm.The decrease in value of the lattice parameter with doping suggests that there is shrinkage in unit cell. The single-phase cubic spinal structure was clearly indicated by the XRD patterns of pure NiFe2O4.The XRD pattern also show that all the samples had formed the cubic single phase spinal structure. Dielectric properties have been studied in the frequency range of 1 kHz to 5 MHz. Permittivity and tangent loss (tanΞ΄) decreases with the substitution of Ce3+ in parent crystal structure.
Accelerated generation of free radicals by iron oxide nanoparticles in the pr...Catherine Oliver
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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.
Synthesis and structural characterization of cd s nanocrystals added with pb2+eSAT Journals
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Abstract
For the past few years, the prepration and characterization of nanocrystals of materials have become an interesting area in the
research activity. CdS (Cadmium Sulphide) is a well known semi conducting material which finds applications in optical devices.
In the present study, we have made an attempt to investigate the effect of Pb2+ as impurity on the properties of CdS nanocrystals.
The samples were prepared by using simple domestic microwave assisted solvothermal method with ethylene glycol as solvant.
The samples prepared were annealed to have good ordering. X-ray diffraction measurements were carried out for all the smples.
The grain size, lattice parameter and yield were determined. The colour before and after annealing was noted. EDX and SEM
analyses were also done. The prepared samples were electrically characterized by making dielectric measurements on the
prepared pellets. The present study indicates that the polarization mechanism in the nano crystals considered is mainly
contributed by the space charge polarization.
Keywords: Semiconducting II βIV materieals, Cadmium sulphide, XRD patterns, solvothermal method, electrical
measurements
New benzotriozole phthalocyanine nickel(ii) photostabilizer for low density p...Alexander Decker
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This document summarizes the synthesis and characterization of a new benzotriazole phthalocyanine nickel(II) complex to be used as a photostabilizer for low density polyethylene. The complex was prepared and characterized using elemental analysis and FT-IR spectroscopy. Experimental investigation showed that this complex acts as an excellent photostabilizer for LDPE, providing stabilization through multiple pathways, unlike commercial antioxidants which typically offer only single mechanisms of protection. Testing revealed that the complex performed better than LDPE samples containing other common antioxidants at preventing degradation when exposed to UV light over time. Therefore, the complex is a promising new photostabilizer for improving the UV resistance of LDPE.
This document provides a technical review of secure banking using RSA and AES encryption methodologies. It discusses how RSA and AES are commonly used encryption standards for secure data transmission between ATMs and bank servers. The document first provides background on ATM security measures and risks of attacks. It then reviews related work analyzing encryption techniques. The document proposes using a one-time password in addition to a PIN for ATM authentication. It concludes that implementing encryption standards like RSA and AES can make transactions more secure and build trust in online banking.
This document analyzes the performance of various modulation schemes for achieving energy efficient communication over fading channels in wireless sensor networks. It finds that for long transmission distances, low-order modulations like BPSK are optimal due to their lower SNR requirements. However, as transmission distance decreases, higher-order modulations like 16-QAM and 64-QAM become more optimal since they can transmit more bits per symbol, outweighing their higher SNR needs. Simulations show lifetime extensions up to 550% are possible in short-range networks by using higher-order modulations instead of just BPSK. The optimal modulation depends on transmission distance and balancing the energy used by electronic components versus power amplifiers.
This document provides a review of mobility management techniques in vehicular ad hoc networks (VANETs). It discusses three modes of communication in VANETs: vehicle-to-infrastructure (V2I), vehicle-to-vehicle (V2V), and hybrid vehicle (HV) communication. For each communication mode, different mobility management schemes are required due to their unique characteristics. The document also discusses mobility management challenges in VANETs and outlines some open research issues in improving mobility management for seamless communication in these dynamic networks.
This document provides a review of different techniques for segmenting brain MRI images to detect tumors. It compares the K-means and Fuzzy C-means clustering algorithms. K-means is an exclusive clustering algorithm that groups data points into distinct clusters, while Fuzzy C-means is an overlapping clustering algorithm that allows data points to belong to multiple clusters. The document finds that Fuzzy C-means requires more time for brain tumor detection compared to other methods like hierarchical clustering or K-means. It also reviews related work applying these clustering algorithms to segment brain MRI images.
1) The document simulates and compares the performance of AODV and DSDV routing protocols in a mobile ad hoc network under three conditions: when users are fixed, when users move towards the base station, and when users move away from the base station.
2) The results show that both protocols have higher packet delivery and lower packet loss when users are either fixed or moving towards the base station, since signal strength is better in those scenarios. Performance degrades when users move away from the base station due to weaker signals.
3) AODV generally has better performance than DSDV, with higher throughput and packet delivery rates observed across the different user mobility conditions.
This document describes the design and implementation of 4-bit QPSK and 256-bit QAM modulation techniques using MATLAB. It compares the two techniques based on SNR, BER, and efficiency. The key steps of implementing each technique in MATLAB are outlined, including generating random bits, modulation, adding noise, and measuring BER. Simulation results show scatter plots and eye diagrams of the modulated signals. A table compares the results, showing that 256-bit QAM provides better performance than 4-bit QPSK. The document concludes that QAM modulation is more effective for digital transmission systems.
The document proposes a hybrid technique using Anisotropic Scale Invariant Feature Transform (A-SIFT) and Robust Ensemble Support Vector Machine (RESVM) to accurately identify faces in images. A-SIFT improves upon traditional SIFT by applying anisotropic scaling to extract richer directional keypoints. Keypoints are processed with RESVM and hypothesis testing to increase accuracy above 95% by repeatedly reprocessing images until the threshold is met. The technique was tested on similar and different facial images and achieved better results than SIFT in retrieval time and reduced keypoints.
This document studies the effects of dielectric superstrate thickness on microstrip patch antenna parameters. Three types of probes-fed patch antennas (rectangular, circular, and square) were designed to operate at 2.4 GHz using Arlondiclad 880 substrate. The antennas were tested with and without an Arlondiclad 880 superstrate of varying thicknesses. It was found that adding a superstrate slightly degraded performance by lowering the resonant frequency and increasing return loss and VSWR, while decreasing bandwidth and gain. Specifically, increasing the superstrate thickness or dielectric constant resulted in greater changes to the antenna parameters.
This document describes a wireless environment monitoring system that utilizes soil energy as a sustainable power source for wireless sensors. The system uses a microbial fuel cell to generate electricity from the microbial activity in soil. Two microbial fuel cells were created using different soil types and various additives to produce different current and voltage outputs. An electronic circuit was designed on a printed circuit board with components like a microcontroller and ZigBee transceiver. Sensors for temperature and humidity were connected to the circuit to monitor the environment wirelessly. The system provides a low-cost way to power remote sensors without needing battery replacement and avoids the high costs of wiring a power source.
1) The document proposes a model for a frequency tunable inverted-F antenna that uses ferrite material.
2) The resonant frequency of the antenna can be significantly shifted from 2.41GHz to 3.15GHz, a 31% shift, by increasing the static magnetic field placed on the ferrite material.
3) Altering the permeability of the ferrite allows tuning of the antenna's resonant frequency without changing the physical dimensions, providing flexibility to operate over a wide frequency range.
This document summarizes a research paper that presents a speech enhancement method using stationary wavelet transform. The method first classifies speech into voiced, unvoiced, and silence regions based on short-time energy. It then applies different thresholding techniques to the wavelet coefficients of each region - modified hard thresholding for voiced speech, semi-soft thresholding for unvoiced speech, and setting coefficients to zero for silence. Experimental results using speech from the TIMIT database corrupted with white Gaussian noise at various SNR levels show improved performance over other popular denoising methods.
This document reviews the design of an energy-optimized wireless sensor node that encrypts data for transmission. It discusses how sensing schemes that group nodes into clusters and transmit aggregated data can reduce energy consumption compared to individual node transmissions. The proposed node design calculates the minimum transmission power needed based on received signal strength and uses a periodic sleep/wake cycle to optimize energy when not sensing or transmitting. It aims to encrypt data at both the node and network level to further optimize energy usage for wireless communication.
This document discusses group consumption modes. It analyzes factors that impact group consumption, including external environmental factors like technological developments enabling new forms of online and offline interactions, as well as internal motivational factors at both the group and individual level. The document then proposes that group consumption modes can be divided into four types based on two dimensions: vertical (group relationship intensity) and horizontal (consumption action period). These four types are instrument-oriented, information-oriented, enjoyment-oriented, and relationship-oriented consumption modes. Finally, the document notes that consumption modes are dynamic and can evolve over time.
The document summarizes a study of different microstrip patch antenna configurations with slotted ground planes. Three antenna designs were proposed and their performance evaluated through simulation: a conventional square patch, an elliptical patch, and a star-shaped patch. All antennas were mounted on an FR4 substrate. The effects of adding different slot patterns to the ground plane on resonance frequency, bandwidth, gain and efficiency were analyzed parametrically. Key findings were that reshaping the patch and adding slots increased bandwidth and shifted resonance frequency. The elliptical and star patches in particular performed better than the conventional design. Three antenna configurations were selected for fabrication and measurement based on the simulations: a conventional patch with a slot under the patch, an elliptical patch with slots
1) The document describes a study conducted to improve call drop rates in a GSM network through RF optimization.
2) Drive testing was performed before and after optimization using TEMS software to record network parameters like RxLevel, RxQuality, and events.
3) Analysis found call drops were occurring due to issues like handover failures between sectors, interference from adjacent channels, and overshooting due to antenna tilt.
4) Corrective actions taken included defining neighbors between sectors, adjusting frequencies to reduce interference, and lowering the mechanical tilt of an antenna.
5) Post-optimization drive testing showed improvements in RxLevel, RxQuality, and a reduction in dropped calls.
This document describes the design of an intelligent autonomous wheeled robot that uses RF transmission for communication. The robot has two modes - automatic mode where it can make its own decisions, and user control mode where a user can control it remotely. It is designed using a microcontroller and can perform tasks like object recognition using computer vision and color detection in MATLAB, as well as wall painting using pneumatic systems. The robot's movement is controlled by DC motors and it uses sensors like ultrasonic sensors and gas sensors to navigate autonomously. RF transmission allows communication between the robot and a remote control unit. The overall aim is to develop a low-cost robotic system for industrial applications like material handling.
This document reviews cryptography techniques to secure the Ad-hoc On-Demand Distance Vector (AODV) routing protocol in mobile ad-hoc networks. It discusses various types of attacks on AODV like impersonation, denial of service, eavesdropping, black hole attacks, wormhole attacks, and Sybil attacks. It then proposes using the RC6 cryptography algorithm to secure AODV by encrypting data packets and detecting and removing malicious nodes launching black hole attacks. Simulation results show that after applying RC6, the packet delivery ratio and throughput of AODV increase while delay decreases, improving the security and performance of the network under attack.
The document describes a proposed modification to the conventional Booth multiplier that aims to increase its speed by applying concepts from Vedic mathematics. Specifically, it utilizes the Urdhva Tiryakbhyam formula to generate all partial products concurrently rather than sequentially. The proposed 8x8 bit multiplier was coded in VHDL, simulated, and found to have a path delay 44.35% lower than a conventional Booth multiplier, demonstrating its potential for higher speed.
This document discusses image deblurring techniques. It begins by introducing image restoration and focusing on image deblurring. It then discusses challenges with image deblurring being an ill-posed problem. It reviews existing approaches to screen image deconvolution including estimating point spread functions and iteratively estimating blur kernels and sharp images. The document also discusses handling spatially variant blur and summarizes the relationship between the proposed method and previous work for different blur types. It proposes using color filters in the aperture to exploit parallax cues for segmentation and blur estimation. Finally, it proposes moving the image sensor circularly during exposure to prevent high frequency attenuation from motion blur.
This document describes modeling an adaptive controller for an aircraft roll control system using PID, fuzzy-PID, and genetic algorithm. It begins by introducing the aircraft roll control system and motivation for developing an adaptive controller to minimize errors from noisy analog sensor signals. It then provides the mathematical model of aircraft roll dynamics and describes modeling the real-time flight control system in MATLAB/Simulink. The document evaluates PID, fuzzy-PID, and PID-GA (genetic algorithm) controllers for aircraft roll control and finds that the PID-GA controller delivers the best performance.
Temple of Asclepius in Thrace. Excavation resultsKrassimira Luka
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The temple and the sanctuary around were dedicated to Asklepios Zmidrenus. This name has been known since 1875 when an inscription dedicated to him was discovered in Rome. The inscription is dated in 227 AD and was left by soldiers originating from the city of Philippopolis (modern Plovdiv).
This document provides an overview of wound healing, its functions, stages, mechanisms, factors affecting it, and complications.
A wound is a break in the integrity of the skin or tissues, which may be associated with disruption of the structure and function.
Healing is the bodyβs response to injury in an attempt to restore normal structure and functions.
Healing can occur in two ways: Regeneration and Repair
There are 4 phases of wound healing: hemostasis, inflammation, proliferation, and remodeling. This document also describes the mechanism of wound healing. Factors that affect healing include infection, uncontrolled diabetes, poor nutrition, age, anemia, the presence of foreign bodies, etc.
Complications of wound healing like infection, hyperpigmentation of scar, contractures, and keloid formation.
A Free 200-Page eBook ~ Brain and Mind Exercise.pptxOH TEIK BIN
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(A Free eBook comprising 3 Sets of Presentation of a selection of Puzzles, Brain Teasers and Thinking Problems to exercise both the mind and the Right and Left Brain. To help keep the mind and brain fit and healthy. Good for both the young and old alike.
Answers are given for all the puzzles and problems.)
With Metta,
Bro. Oh Teik Bin ππ€π€π₯°
How to Download & Install Module From the Odoo App Store in Odoo 17Celine George
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Custom modules offer the flexibility to extend Odoo's capabilities, address unique requirements, and optimize workflows to align seamlessly with your organization's processes. By leveraging custom modules, businesses can unlock greater efficiency, productivity, and innovation, empowering them to stay competitive in today's dynamic market landscape. In this tutorial, we'll guide you step by step on how to easily download and install modules from the Odoo App Store.
How to Manage Reception Report in Odoo 17Celine George
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A business may deal with both sales and purchases occasionally. They buy things from vendors and then sell them to their customers. Such dealings can be confusing at times. Because multiple clients may inquire about the same product at the same time, after purchasing those products, customers must be assigned to them. Odoo has a tool called Reception Report that can be used to complete this assignment. By enabling this, a reception report comes automatically after confirming a receipt, from which we can assign products to orders.
Gender and Mental Health - Counselling and Family Therapy Applications and In...PsychoTech Services
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A proprietary approach developed by bringing together the best of learning theories from Psychology, design principles from the world of visualization, and pedagogical methods from over a decade of training experience, that enables you to: Learn better, faster!
How to Setup Default Value for a Field in Odoo 17Celine George
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In Odoo, we can set a default value for a field during the creation of a record for a model. We have many methods in odoo for setting a default value to the field.
Accounting for Restricted Grants When and How To Record Properly
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A0350107
1. IOSR Journal of Applied Physics (IOSR-JAP)
e-ISSN: 2278-4861. Volume 3, Issue 5 (Mar. - Apr. 2013), PP 01-07
www.iosrjournals.org
www.iosrjournals.org 1 | Page
Debye temperature calculation from various experimental
methods for ππ π± π πβπ± ππ₯ grown from aqueous solution
C.V.Somasundari and N.Neelakanda Pillai
Department of Physics, Arignar Anna College, Aralvoimoli
Abstract: Mixed crystals of alkali halides find their applications in optical, opto-electronics and electronic
devices. In the present study the pure and ZnS added mixed crystals ππ π₯ πΎ1βπ₯ πΆπ were grown from the aqueous
solution. The grown crystals were characterized by taking XRD, TG / DTA and Vickerβs micro hardness
measurement. The Debye temperature is an important parameter of a solid. Several methods of evaluating
Debye temperature are available. In the present study Debye temperatures were calculated from the Debye-
waller factor, melting point and microhardness. The results were compared with the Kopp Neumann relation.
Key words : Mixed crystals, Alkali halides, Debye temperature, Debye frequency
I. Introduction
The Debye temperature is an important parameter of a solid. Several methods of evaluating the Debye
temperature are available. Alers (1965) reviewed number of these. In the present paper deals with four
different methods of calculating Debye temperature. The methods considered here are (a) from melting point (b)
from Debye-waller factor (c) from microhardness (d) from Kopp-Neumann relation. The comparison of the
results by the first three methods with those the last one enables one to judge the accuracy of the various
methods.
Mixed crystals of alkali halides find their applications in optical, Opto electronics and electronic
devices. So, the grow of alkali halide mixed crystals are interesting and important today. In this present study
totally fourteen crystals (5 pure mixed, 5 doped mixed, 2 pure end members and 2 doped end members).
II. Materials and Methods
2.1. Growth of Sample Crystals
Analytical Reagent (AR) grade NaCl and KCl substance along with doubly distilled water were used
for the growth of single crystals. An aqueous solution of the salt with desired molecular ratio was prepared at
supersaturated concentration and seed crystals were used to grow the sample crystals. The temperature and
volume were kept constant respectively at 32Β°C and 25ml for all the crystals. IN solution of 2.5ml ZnS was
added to the 25ml supersaturated solution. In the present study total of fourteen crystals (five pure mixed
crystals, five doped mixed crystals, two pure end members and two doped end members) for various values X
viz. 0.2, 0.4, 0.5, 0.6 and 0.8 were grown in identical conditions.
2.2. Estimation of Composition
The composition of pure and ZnS added crystals were accurately calculated from the EDAX spectrum
taken by scanning electron microscope (Model FEI Quanta FEG 200). The concentration of Zn and S atom also
calculated for the doped system.
2.3. Debye temperature Calculation
Debye temperature of the crystals can be determined from various experimental measurements like
melting point, Debye waller factor, hardness number, Kopp-Newmann relation etc.
2.3.1. From melting point
Debye temperature can be estimated from the melting point (Tm) of the crystal using the formula [1]
ΞΈm = C
TM
MV
2
3
1
2
where C is a constant depending on the X-ray intensity data structure. The formula unit volume was estimated
from the lattice constant. A value of 450 has been used for C as the structure is of NaCl type. This value is the
average of the values evaluated from the known values of Debye temperature for the end member crystals. The
melting point of all the grown crystals were determined from TG / DTA curve recorded on seiko TG/DTA 6200
system at heating ramp of 10Β°C C/min. Nitrogen was used as purge gas at a flow rate of 500ml/min. The
powder sample was encapsulated in platinum pass and the sample pan material was also platinum.
2. Debye temperature calculation from various experimental methods for ππ π₯ πΎ1βπ₯ πΆπ grown from
www.iosrjournals.org 2 | Page
2.3.2. From Debye waller factor
The mean Debye waller factor was determined from the XRD data taken by using PAN analytical,
diffractometer with scintillation counter and monochromated CuKβ Ξ» = 1.5406 AΒ° radiation. The reflections
were indexed following the procedures of Lipson and Steeple [2].
Analysis of the X-ray diffraction peaks by the available methods [3] shows that for the mixed crystals,
all the X-ray diffraction peaks can be indexed with two F.C.C. phases instead of one which shows the existence
of two F.C.C. phases one phase nearly corresponds to pure NaCl and the other phase nearly corresponds to pure
KCl.
The mean Debye-waller factor for all the fourteen grown crystals were determined by a method similar
to that followed by Mahadevan and his co-workers [1, 4 -10]. As the number of reflections are limited, only a
common Debye-waller factor was determined for all the atoms in every system by using Wilson theory [11].
The structure factors are calculated using the relations
F h k l = 4 fNa
+
Β± fCl
β
for NaCl
F h k l = 4 fk
+
Β± fCl
β
for KCl
F h k l = 4 x fNa
+
Β± fCl
β
+ 1 β x fk
+
Β± fCl
β
for mixed system.
Here fNa
+
, fk
+
and fCl
β
are the respective scattering factors for Na+
,K+
and Cl ions taken from the
literature [12]. and (1 β x) are the composition of NaCl and KCl present in the mixed system. The plus
sign for the reflections with even value of h+k+l and minus sign for those with odd values of h+k+l.
The Bragg intensity equation may be written as
Ie
Ic = K exp
β2Bsin2
ΞΈ
Ξ»2
The mean Debye-waller factor (Bobs) was obtained by taking a least squares approximation of
ln Ie
Ic against
sin 2ΞΈ
Ξ»2 . Ie is experimentally observed (intergrated) intensity. Ic is the calculated intensity, K
is the scale factor, is the Bragg angle and is the wavelength of radiation used.
The presence of mixing of ions creates a static contribution in the case of mixed crystals. Replacement
of ions possible only between Na+
and K+
ions. Bstatic for the mixed crystals was calculated using the
relation.
Bstatic = x 1 β x rA β rB
2
.
where x and (1 β x) are respective mole fractions of NaCl and KCl in the mixed crystals and rA
and rB are the respective ionic radii of Na+
and K+
.
Observed Debye-waller factors for the mixed crystals is given by
Bobserved = Bstatic + Bthermal
Bthermal was calculated from the above relation and the Debye temperature, mean square amplitude of
vibration and Debye frequency were determined from the methods followed by Neelakanda pillai and
Mahadevan [1].
The Debye temperature ΞΈD was obtained from the Debye-waller theory expressions.
For pure crystals Bobs =
6h2
mKT
W(x) and for mixed crystals Bthermal =
6h2
mKT
W(x).
Where m is the mean atomic mass, T is the absolute temperature (298Β°K) at which X-ray diffraction
intensities were measured, h is the plankβs constant and K is the Boltzmannβs constant. The function w(x)
is given by
w x =
Ο(x)
x2
+
1
4
x
Where x =
ΞΈD
T
and Ο(x) is an integral.
Ο x =
ey
1 β ey
dy.
x
0
The value of w(x) for a wide range of are tabulated by Benson and Gill [13], ΞΈD, the Debye
temperature was evaluated by using the above expression.
The mean square amplitude of vibration < u2
> was obtained from [1]
B = 8Ο2
< u2
>. The Debye frequency was obtained from the Debye temperature using the relation
[1] FD =
ΞΈD
h
2.3.3. From microhardness value
Debye temperature can also be estimated from the microhardness value calculated from Vickerβs
microhardness measurement reported else where [14] using the relation.
ΞΈH = B H
1
2 V
1
6 M
β1
2
Where B is a constant and its value is 348. Calculated from the known data for the end member
3. Debye temperature calculation from various experimental methods for ππ π₯ πΎ1βπ₯ πΆπ grown from
www.iosrjournals.org 3 | Page
crystals.
2.3.4. From Kopp-Neumann relation
Sirdeshmukh and Srinivas [15] reviewed the data on fourteen alkali halide mixed crystals and
concluded that, by and large, the composition dependence of ΞΈD(ie. ΞΈ) of alkali halide mixed crystals is well
described by the Kopp - Neumann relation given by
ΞΈβ3
= x ΞΈA
β3
+ 1 β x ΞΈB
β3
Where ΞΈA and ΞΈB are the temperatures of the end member crystals.
III. Results and discussion
3.1. Growth of sample crystals
Pure and undoped mixed crystals of NaxK1βxCl are provided in photograph. 1 and ZnS doped pure
and mixed crystals of NaxK1βxCl are provided in photograph 2. It is found that all the fourteen crystals grown
were stable and transparent. The mixed crystals are found to be harder than the end member crystals and the
ZnS added crystals were more harder than the mixed crystals.
Photograph : 1.Undoped NaxK(1-x)Cl Crystals Photograph:2. ZnS doped NaxK(1-x)Cl Crystals
3.2. Estimation of Bulk composition
The composition of all the crystals except the undoped end member crystals were estimated from the
EDAX data. The estimated composition along with the weight percentage of ππ+
, πΎ+
, πΆπβ
and ππ2+
(for
doped crystals only) are provided in Table 1. It is found that the estimated compositions of all the mixed crystals
were well agree with the composition taken. EDAX spectrum of undoped Na0.5K0.5Cl is provided in Fig.1. for
illustration.
Fig.1. EDAX Spectrum of undoped Na0.5 K0.5Cl
4. Debye temperature calculation from various experimental methods for ππ π₯ πΎ1βπ₯ πΆπ grown from
www.iosrjournals.org 4 | Page
Table .1.Weight percentage and estimated composition values together with the composition taken for
pure and ZnS doped crystals.
System
Weight Percentage of
Estimated composition
Na K Cl Zn
Undoped mixed crystals
NaCl
KCl
NaCl0.2 KCl0.8
NaCl0.4 KCl0.6
NaCl0.5 KCl0.5
NaCl0.6 KCl0.4
NaCl0.8 KCl0.2
ZnS doped mixed crystals
NaCl
KCl
NaCl0.2 KCl0.8
NaCl0.4 KCl0.6
NaCl0.5 KCl0.5
NaCl0.6 KCl0.4
NaCl0.8 KCl0.2
14.95
35.38
01.46
02.15
04.75
20.08
39.98
37.77
-
01.89
04.15
01.16
24.62
02.38
00.02
00.54
44.25
45.64
42.81
22.29
00.28
-
15.11
13.74
14.28
13.97
27.63
14.76
19.15
64.08
54.29
52.21
52.44
57.63
59.74
54.95
82.48
81.88
79.34
82.57
46.70
81.14
-
-
-
-
-
-
-
07.28
00.42
00.46
00.45
0037
00.22
00.30
NaCl
KCl
NaCl0.135 KCl0.865
NaCl0.248 KCl0.752
NaCl0.339 KCl0.661
NaCl0.602 KCl0.398
NaCl0.91 KCl0.099
NaCl
KCl
NaCl0.191 KCl0.809
NaCl0.386 KCl0.614
NaCl0.443 KCl0.55
NaCl0.601 KCl0.392
NaCl0.697 KCl0.303
3.3. Lattice Parameter
Analysis of the X-ray diffraction peaks of the undoped and doped mixed crystals in the present study
by the available methods. It has been found that all the X-ray diffraction peaks can be indexed with two F.C.C.
lattices in stead of one, which shows the existence of two F.C.C. phases. The calculated lattice parameters show
that one phase nearly corresponds to pure NaCl and the other phase corresponds to pure KCl. The lattice
parameters of all the fourteen crystals are provided in Table.2 and the XRD pattern of the sample undoped
Na0.5 K0.5Cl is provided in Fig.2 for illustration.
Table .2. Lattice parameters together with the composition taken for pure and doped crystals
System
Lattice Parameter (a)
For NaCl Phase For KCl phase Average
Undoped mixed crystals
NaCl
KCl
NaCl0.2 KCl0.8
NaCl0.4 KCl0.6
NaCl0.5 KCl0.5
NaCl0.6 KCl0.4
5.633
-
5.656
5.643
5.652
5.641
-
6.269
6.306
6.264
6.294
6.289
5.633
6.269
5.981
5.954
5.973
5.965
0
200
400
600
800
1000
1200
1400
1600
1800
0 20 40 60 80
counts
Angle
Fig .2. XRD Pattern for the undoped Na0.5K0.5Cl
(111)
(200)
(220)
(220)
(222)
(400)
(420)
5. Debye temperature calculation from various experimental methods for ππ π₯ πΎ1βπ₯ πΆπ grown from
www.iosrjournals.org 5 | Page
NaCl0.8 KCl0.2
ZnS doped mixed crystals
NaCl
KCl
NaCl0.2 KCl0.8
NaCl0.4 KCl0.6
NaCl0.5 KCl0.5
NaCl0.6 KCl0.4
NaCl0.8 KCl0.2
5.633
5.630
-
5.641
5.618
5.625
5.618
5.625
6.629
-
6.311
6.294
6.279
6.289
6.269
6.248
6.131
5.630
6.311
5.968
5.949
5.958
5.944
5.703
3.4. Debye temperature
3.4.1. From melting paint
Molecular weight, lattice parameter, melting point and the calculated Debye temperature are provided
in Table. 3 for all the systems. It is found that the Debye temperature calculated from the melting point vary
non-linearly with composition. The melting point of the end member crystals determined well agree with the
literature value which is provided in the bracket.
Table . 3. Molecular weight, lattice constant, melting point and Debye temperature together with the
composition taken for pure and doped crystals.
System
Molecular
weight
Lattice constant Melting pt
Debye
Temperature
Undoped mixed crystals
NaCl
KCl
NaCl0.2 KCl0.8
NaCl0.4 KCl0.6
NaCl0.5 KCl0.5
NaCl0.6 KCl0.4
NaCl0.8 KCl0.2
ZnS doped mixed
crystals
NaCl
KCl
NaCl0.2 KCl0.8
NaCl0.4 KCl0.6
NaCl0.5 KCl0.5
NaCl0.6 KCl0.4
NaCl0.8 KCl0.2
58.44
74.56
72.38
70.56
69.10
64.86
60.56
58.44
74.56
72.38
70.56
69.10
64.86
60.56
5.633
6.269
5.981
5.954
5.973
5.965
6.131
5.630
6.311
5.968
5.949
5.958
5.944
5.703
1081.3
1051.1
1032.6
1038.3
977.7
942.7
1055.6
1083.8
1049.2
1047.1
1032.
1045.6
938.4
939.5
253
206
214
218
213.5
218.4
235
249.3
209.1
216
217.4
221.01
216.28
227.07
3.4.2. Debye Waller factor
The Debye-waller factors Bsta , Bob and Bther and the Debye temperature are given in Table.4 for all
the systems. The reported value of Debye temperature for the end member crystals are provided in bracket. It is
found that the observed value for the end member crystals well agreed with the reported value given in bracket.
The bulk composition dependence of Debye-waller factor is highly non-linear. The observed Debye
temperature is also independent of the composition of the mixed crystals.
6. Debye temperature calculation from various experimental methods for ππ π₯ πΎ1βπ₯ πΆπ grown from
www.iosrjournals.org 6 | Page
Table . 4. Debye waller factors (B) and Debye temperature π½ π« together with the composition
taken for pure and doped crystals.
System π π¬ππ(πΒ°) π π π¨ππ¬ πππ‘ππ« = π π¨ππ¬ β π π¬ππ π π π π ππ ππ
ππ³
Undoped mixed
crystals
NaCl
KCl
NaCl0.2 KCl0.8
NaCl0.4 KCl0.6
NaCl0.5 KCl0.5
NaCl0.6 KCl0.4
NaCl0.8 KCl0.2
ZnS doped mixed
crystals
NaCl
KCl
NaCl0.2 KCl0.8
NaCl0.4 KCl0.6
NaCl0.5 KCl0.5
NaCl0.6 KCl0.4
NaCl0.8 KCl0.2
-
-
0.0168
0.0269
0.0323
0.0348
0.0130
-
-
0.0212
0.0341
0.0355
0.0345
0.0304
2.5565
-0.5455
4.979
-1.564
3.0765
2.6375
1.926
5.7
6.01
3.7545
-4.886
1.479
-1.843
-1.222
2.5565
0.5455
4.962
1.5909
3.0442
2.603
1.913
5.7
6.01
3.733
-4.9201
1.4435
-1.8775
-1.2524
152
294
138.6
249.45
181.5
202.8
261
144
124
164.1
143.3
268.35
239.4
297.9
1.432
3/166
6.123
3.887
5.195
4.224
3.418
2.116
1.487
3.418
2.985
5.589
4.986
6.204
3.4.3. From microhardness
The measured hardness value and the Debye temperature calculated are provided in Table.5. It is found
that here also the Debye temperature shows non-linear variation with composition.
Table .5. Hardness number Hv and Debye temperature π π together with the composition taken for pur
and doped crystals.
System Hardness number for 25gm π π
Undoped mixed crystals
NaCl
KCl
NaCl0.2 KCl0.8
NaCl0.4 KCl0.6
NaCl0.5 KCl0.5
NaCl0.6 KCl0.4
NaCl0.8 KCl0.2
ZnS doped mixed crystals
NaCl
KCl
NaCl0.2 KCl0.8
NaCl0.4 KCl0.6
NaCl0.5 KCl0.5
NaCl0.6 KCl0.4
NaCl0.8 KCl0.2
9.515
7.285
6.650
15.150
7.705
15.950
15.800
17.750
13.850
15.550
9.585
16.700
6.485
17.750
253
206
195.7
298.49
215.45
319.74
333.89
345.22
285.84
298.93
237.32
316.79
203.52
341.32
3.4.4. Comparison of Debye temperatures calculated with Kopp-Neumann relation
Debye temperatures observed from all the three methods of the mixed crystals are provided in Table.6.
It shows a non-linear variation with composition, Debye temperature observed from the melting point of the
mixed crystals well agree with those calculated from the Kopp-Neumann relation, while observed from the
Debye-waller factor are less than the values observed from the Kopp-Neumann relation except for some
crystals. After analysing the data on the Debye temperatures of a large number of mixed crystals, Sirdeshmukh
and Srinivas [15] concluded that the observed values of Debye temperatures from the Debye-waller factor are
lower than those calculated from composition. The deviation of Debye temperature from the Kopp-Neumann
relation may be due to increase in Vibrational entropy.
Mahadevan and his co-workers [1,4-10] observed the Debye temperature for ternary mixed crystals of
alkali halide crystals, they have also reported that the Debye temperature varies non-linearly with composition.
7. Debye temperature calculation from various experimental methods for ππ π₯ πΎ1βπ₯ πΆπ grown from
www.iosrjournals.org 7 | Page
Ahtee and Koshi made similar observation in the case of KCl β KBr mixed crystals and attributed the
enhancement of the Debye-waller factors to an increase in the vibrational entropy.
Table .6. Debye temperature calculated from melting point π π and Kopp-Neumann relation
π πtogether with the composition taken for pure and doped crystals.
System
Debye Temperature
π π π π π π π π
Undoped mixed
crystals
NaCl
KCl
NaCl0.2 KCl0.8
NaCl0.4 KCl0.6
NaCl0.5 KCl0.5
NaCl0.6 KCl0.4
NaCl0.8 KCl0.2
ZnS doped mixed
crystals
NaCl
KCl
NaCl0.2 KCl0.8
NaCl0.4 KCl0.6
NaCl0.5 KCl0.5
NaCl0.6 KCl0.4
NaCl0.8 KCl0.2
253
206
214
218
213.5
218.4
235
249.3
209.1
216
217.4
221.01
216.28
227.07
152
294
138.6
249.45
181.5
202.8
261
144
124
164.1
143.3
268.35
239.4
297.9
253
206
195.7
298.49
215.45
319.74
333.89
345.22
285.84
298.93
237.32
316.79
203.52
341.32
253
206
210.4
214.5
218
229.5
245.6
253
206
212.4
219.9
222.2
229.4
234.3
IV. Conclusion
In the present study the Debye temperature of all the pure and ZnS added crystals were determined
from the experimental values of melting point, Debye-waller factor and microhardness. Of these, Debye
temperature calculated from the melting point temperature for all the grown crystals well agree with the Debye
temperature calculated from the Kopp-Neumann relation. From this study it is concluded that the Debye
temperature calculated from the melting point is more accurate and when doped the accuracy gets increases
further.
References
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