Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

2022

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 26761 - 26790 of 32042

Full-Text Articles in Entire DC Network

Synthesis And Antioxidant Activities Of Benzylic Bromophenols Inclusive Of Natural Products, Çeti̇n Bayrak, Eda Mehtap Üç, Mohsen Rezaei, İlhami̇ Gülçi̇n, Abdullah Menzek Jan 2022

Synthesis And Antioxidant Activities Of Benzylic Bromophenols Inclusive Of Natural Products, Çeti̇n Bayrak, Eda Mehtap Üç, Mohsen Rezaei, İlhami̇ Gülçi̇n, Abdullah Menzek

Turkish Journal of Chemistry

The synthesis of natural products 2-(2,3-dibromo-4,5-dihydroxyphenyl)acetic acid (1) and 2-(2,6-dibromo-3,5-dihydroxyphenyl)acetic acid (2) and as well as their derivatives 25 and 26 were carried out by substitution, hydrolysis and demethylation reactions of the corresponding four benzyl bromides. The antioxidant potentials of benzylic acid-derived bromophenols were, for the first time, appraised by several outstanding bioanalytical methods. Besides these, we estimated the antioxidant effects which were studied using the methods of DPPH·, ABTS·+ scavenging activities, ferric (Fe3+) and cupric (Cu2+) ions and Fe3+-TPTZ reducing capacities. Benzylic acid-derived bromophenols were found as effective DPPH·, and …

Go to article

Investigation Of Boron Nanosized Particles Prepared With Various Surfactants And Chitosan In Terms Of Physical Stability And Cell Viability, Emrah Özakar, Mehmet Semi̇h Bi̇ngöl, Ruki̇ye Sevi̇nç Özakar Jan 2022

Investigation Of Boron Nanosized Particles Prepared With Various Surfactants And Chitosan In Terms Of Physical Stability And Cell Viability, Emrah Özakar, Mehmet Semi̇h Bi̇ngöl, Ruki̇ye Sevi̇nç Özakar

Turkish Journal of Chemistry

Nanosuspensions (NS) are one of the new generation drug carrier forms developed to overcome the deficiencies of drugs with poor water solubility or insolubility and are considered to be one of the most successful approaches to formulate compounds in recent years. Boron nitride (BN) is insoluble in water and chemically more stable than carbon, it offers better biological superiority although the application of carbon structures in the biomedical field has increased in recent years. Chitosan is a polymer with excellent processability and biocompatibility thanks to its high dielectric constant. In addition, chitosan has a high affinity for metal ions. This …

Go to article

Homonuclear Nickel(Ii) Metal-Organic Framework-Type Supramolecule: Adsorption And Emission Properties, Idongesit Mbonu, Olusegun Abiola, Hamzah Bawa Jan 2022

Homonuclear Nickel(Ii) Metal-Organic Framework-Type Supramolecule: Adsorption And Emission Properties, Idongesit Mbonu, Olusegun Abiola, Hamzah Bawa

Turkish Journal of Chemistry

Coordination-driven self-assembly of nickel (II) ions with equimolar amounts of 1, 10 phenanthroline, and benzoic acid was used to create homonuclear nickel (II) MOF-type supramolecule. Single crystal X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, photoluminescence measurement, FT-IR, UV-visible spectroscopy, and nitrogen physisorption measurement were used to characterize the compound. The single crystal X-ray diffraction study reveals that the synthesized compound is two-dimensional with pores in the structure. The homonuclear nickel (II) MOF-type supramolecule crystallized in a triclinic crystal system, with space group P-1 (No.2) and unit cell parameters a = 9.2053(4) Ǻ, b = 13.2964(5) Ǻ, c = 15.8998(6) …

Go to article

Synthesis, Characterization, Computational Analyses, In Silico Admet Studies, And Inhibitory Action Against Sars-Cov-2 Main Protease (Mpro) Of A Schiff Base, Songül Şahi̇n, Necmi̇ Dege Jan 2022

Synthesis, Characterization, Computational Analyses, In Silico Admet Studies, And Inhibitory Action Against Sars-Cov-2 Main Protease (Mpro) Of A Schiff Base, Songül Şahi̇n, Necmi̇ Dege

Turkish Journal of Chemistry

COVID-19 disease caused by the severe acute respiratory syndrome coronavirus (SARS-CoV-2) has struck the whole world and raised severe health, economic, and social problems. Many scientists struggled to find a vaccine or an antiviral drug. Eventually, both vaccines and recommended drugs, repurposed drugs, or drug combinations were found, but new strains of SARS-CoV-2 continue to threaten human life and health. As part of the fight against COVID-19 disease, this study involves an in silico molecular docking analysis on the main protease (Mpro) of SARS-CoV-2. To this aim, a Schiff base compound was synthesized and characterized using spectroscopic techniques, including X-ray, …

Go to article

A Study Of Silicon And Germanium-Based Molecules In Terms Of Solar Cell Devices Performance, Emi̇ne Taniş Jan 2022

A Study Of Silicon And Germanium-Based Molecules In Terms Of Solar Cell Devices Performance, Emi̇ne Taniş

Turkish Journal of Chemistry

Photovoltaic energy sources are increasingly in demand due to the cost of petroleum fuels and concerns about carbon emissions. For this reason, it is important to determine the photovoltaic properties of the compounds that are thought to be suitable for these energy sources. Here, 1,1,2,3,4,5-Hexaphenyl-1H-silole (HPS) and 1,1,2,3,4,5-Hexaphenyl-1H-germole (HPG) compounds that are thought to have excellent photovoltaic properties, electronic and charge transport properties were investigated experimentally and theoretically. The total energies, absorption spectra, Fermi energy (Efl) and work function (φ), maximum open circuit voltage (VOC), reorganization energies (λe and λh), frontier molecular orbital …

Go to article

Ytterbium Oxide Nanofibers: Fabrication And Characterization For Energy Applications, Adem Sarilmaz Jan 2022

Ytterbium Oxide Nanofibers: Fabrication And Characterization For Energy Applications, Adem Sarilmaz

Turkish Journal of Chemistry

Metal oxide nanomaterials are widely used in many applications of renewable energy. Ytterbium oxide (Yb2O3) also attracts attention due to its similar structure to ZnO (~3,26 eV) and TiO2 (~3,36 eV) in terms of bandgap energy. In this study, Yb2O3 belonging to the lanthanide oxide family was produced as nanofiber forms by using the electrospinning technique, which allows for large-scale production, for the first time. The morphological, structural, optical, and phase properties of the produced nanofibers were investigated via XRD, SEM-Mapping, TEM, FTIR, UV-Vis, and XPS characterization techniques. As a result of …

Go to article

Release Of Nifedipine, Furosemide, And Niclosamide Drugs From The Biocompatible Poly(Hema) Hydrogel Structures, Bahar Yilmaz Jan 2022

Release Of Nifedipine, Furosemide, And Niclosamide Drugs From The Biocompatible Poly(Hema) Hydrogel Structures, Bahar Yilmaz

Turkish Journal of Chemistry

The primary aim of this article was to improve the solubility and bioavailability of the drugs nifedipine, niclosamide, and furosemide due to their poor solubility and dissolution rate. Therefore, these drugs require improvement in solubility and dissolution rate in formulation development, especially in solid dosage forms such as hydrogels and capsules. Hydrogel structures were synthesized by using a biocompatible, nontoxic, and protective pure 2-hydroxy ethyl methacrylate (HEMA) monomer. These hydrogel structures were characterized by various techniques such as scanning electron microscopy and Fourier-transformed infrared spectroscopy. In the next step, drug molecules were loaded in the poly (HEMA) hydrogels. Drug releases …

Go to article

Insight Into Electrochemical Degradation Of Cartap (In Padan 95sp) By Boron-Doped Diamond Electrode: Kinetic And Effect Of Water Matrices, Hoang Nguyen Jan 2022

Insight Into Electrochemical Degradation Of Cartap (In Padan 95sp) By Boron-Doped Diamond Electrode: Kinetic And Effect Of Water Matrices, Hoang Nguyen

Turkish Journal of Chemistry

In this work, the kinetic electrochemical degradation of Cartap (CT) (in Padan 95 SP) at boron-doped diamond (BDD) electrode was investigated. This study indicated that the degradation of CT underwent both direct and indirect oxidations. Water matrices can either accelerate or inhibit the removal efficiency of CT: adding 15 mM Cl- improved kCT from 0.039 min-1 to 0.054 min-1 (increased by 38%), while kCT decreased by 61.5% and 64% when increasing the concentration of HCO3- and humic acid (HA) to 15 mM and 15 mg L-1, respectively. CT degradation was inhibited …

Go to article

Targeting Current And Future Threats: Recent Methodological Trends In Environmental Antimicrobial Resistance Research And Their Relationships To Risk Assessment, Tucker R. Burch, Ryan J. Newton, Lee K. Kimbell, Emily Lou Lamartina, Kassidy N. O'Malley, San Marie Victoria Thomson, Christopher Marshall, Patrick J. Mcnamara Jan 2022

Targeting Current And Future Threats: Recent Methodological Trends In Environmental Antimicrobial Resistance Research And Their Relationships To Risk Assessment, Tucker R. Burch, Ryan J. Newton, Lee K. Kimbell, Emily Lou Lamartina, Kassidy N. O'Malley, San Marie Victoria Thomson, Christopher Marshall, Patrick J. Mcnamara

Civil and Environmental Engineering Faculty Research and Publications

Antimicrobial resistance (AMR) is a growing public health threat. Improved surveillance of AMR's genetic indicators in environmental reservoirs should lead to a more comprehensive understanding of the problem at a global scale, as with SARS-CoV-2 monitoring in sewage. However, the “best” monitoring approach is unclear. Some scientific works have emphasized monitoring for the abundance of already-known antimicrobial resistance genes (ARGs); others have emphasized monitoring for the potential of new ARGs to arise. The goal of this study was to examine which methods were employed by highly-cited papers studying AMR in environmental engineering and agricultural systems, thus providing insight into current …

Go to article

Optimized Cancer Detection On Various Magnified Histopathological Colon Imagesbased On Dwt Features And Fcm Clustering, Tina Babu, Tripty Singh, Deepa Gupta, Shahin Hameed Jan 2022

Optimized Cancer Detection On Various Magnified Histopathological Colon Imagesbased On Dwt Features And Fcm Clustering, Tina Babu, Tripty Singh, Deepa Gupta, Shahin Hameed

Turkish Journal of Electrical Engineering and Computer Sciences

Due to the morphological characteristics and other biological aspects in histopathological images, the computerized diagnosis of colon cancer in histopathology images has gained popularity. The images acquired using the histopathology microscope may differ for greater visibility by magnifications. This causes a change in morphological traits leading to intra and inter-observer variability. An automatic colon cancer diagnosis system for various magnification is therefore crucial. This work proposes a magnification independent segmentation approach based on the connected component area and double density dual tree DWT (discrete wavelet transform) coefficients are derived from the segmented region. The derived features are reduced further shortened …

Go to article

Distributed Wireless Sensor Node Localization Based On Penguin Searchoptimization, Md Al Shayokh, Soo Young Shin Jan 2022

Distributed Wireless Sensor Node Localization Based On Penguin Searchoptimization, Md Al Shayokh, Soo Young Shin

Turkish Journal of Electrical Engineering and Computer Sciences

Wireless sensor networks (WSNs) have become popular for sensing areas-of-interest and performing assigned tasks based on information on the location of sensor devices. Localization in WSNs is aimed at designating distinct geographical information to the inordinate nodes within a search area. Biologically inspired algorithms are being applied extensively in WSN localization to determine inordinate nodes more precisely while consuming minimal computation time. An optimization algorithm belonging to the metaheuristic class and named penguin search optimization (PeSOA) is presented in this paper. It utilizes the hunting approaches in a collaborative manner to determine the inordinate nodes within an area of interest. …

Go to article

An Active Contour Model Using Matched Filter And Hessian Matrix For Retinalvessels Segmentation, Mahtab Shabani, Hossein Pourghassem Jan 2022

An Active Contour Model Using Matched Filter And Hessian Matrix For Retinalvessels Segmentation, Mahtab Shabani, Hossein Pourghassem

Turkish Journal of Electrical Engineering and Computer Sciences

Medical image analysis, especially of the retina, plays an important role in diagnostic decision support tools. The properties of retinal blood vessels are used for disease diagnoses such as diabetes, glaucoma, and hypertension. There are some challenges in the utilization of retinal blood vessel patterns such as low contrast and intensity inhomogeneities. Thus, an automatic algorithm for vessel extraction is required. Active contour is a strong method for edge extraction. However, it cannot extract thin vessels and ridges very well. In this research, we propose an improved active contour method that uses discrete wavelet transform for energy minimization to solve …

Go to article

Stressed Or Just Running? Differentiation Of Mental Stress And Physical Activityby Using Machine Learning, Yekta Sai̇d Can Jan 2022

Stressed Or Just Running? Differentiation Of Mental Stress And Physical Activityby Using Machine Learning, Yekta Sai̇d Can

Turkish Journal of Electrical Engineering and Computer Sciences

Recently, modern people have excessive stress in their daily lives. With the advances in physiological sensors and wearable technology, people?s physiological status can be tracked, and stress levels can be recognized for providing beneficial services. Smartwatches and smartbands constitute the majority of wearable devices. Although they have an excellent potential for physiological stress recognition, some crucial issues need to be addressed, such as the resemblance of physiological reaction to stress and physical activity, artifacts caused by movements and low data quality. This paper focused on examining and differentiating physiological responses to both stressors and physical activity. Physiological data are collected …

Go to article

Cover And Contents Jan 2022

Cover And Contents

Turkish Journal of Chemistry

No abstract provided.

Go to article

Assessment Of Environmental Pollutants At Trace Levels Using Ionic Liquids-Based Liquid-Phase Microextraction, Furkan Uzcan, Muhammad Saqaf Jagirani, Mustafa Soylak Jan 2022

Assessment Of Environmental Pollutants At Trace Levels Using Ionic Liquids-Based Liquid-Phase Microextraction, Furkan Uzcan, Muhammad Saqaf Jagirani, Mustafa Soylak

Turkish Journal of Chemistry

Sample preparation is the crucial and most challenging part of analytical chemistry for the speciation of environmental pollutants' traces. Along with the development of the sample preparation methods, the ionic liquid-based microextraction technique plays an important role. Due to the unequivocally unique "green" characteristic of ionic liquids (ILs), they owe their tunable properties, such as highly selective and high reaction efficiency, reusability, and good thermal stability, to present advancements in the sample preparation process. The ionic liquid-based microextraction techniques miniaturize the sample preparation process. Liquid phase microextraction intermediate solvents, desorption solvent extractants, and mediators have been used. They are quoting …

Go to article

Virus Detection Using Bio-Based Analysis Systems: A Review Of Biorecognition Strategies, Nur Meli̇s Kiliç, Di̇lek Odaci Demi̇rkol Jan 2022

Virus Detection Using Bio-Based Analysis Systems: A Review Of Biorecognition Strategies, Nur Meli̇s Kiliç, Di̇lek Odaci Demi̇rkol

Turkish Journal of Chemistry

Infectious illnesses are on the rise in today's world, with serious consequences for animals, plants, and humans. Several infections, including the human immunodeficiency virus, affect a large number of individuals in various countries, particularly in the poorer portions of contemporary society, and continue to cause a variety of health problems. Viruses are tiny parasitic organisms. They are infectious agents that can only reproduce within a live cell of an organism. Viruses may infect any living organism. For clinical pointof- care applications, early detections for harmful agents such as bacteria, viruses are critical. The possibility of worldwide epidemics as a result …

Go to article

Silver Nanoparticles (Agnps) Based Selective Colorimetric Sensor For The Detection Of D-Arabinitol In A Urine Sample, Yuni Retnaningtyas, Siswandono Siswodihardjo, Ari Satia Nugraha Jan 2022

Silver Nanoparticles (Agnps) Based Selective Colorimetric Sensor For The Detection Of D-Arabinitol In A Urine Sample, Yuni Retnaningtyas, Siswandono Siswodihardjo, Ari Satia Nugraha

Turkish Journal of Chemistry

D-arabinitol is a sugar alcohol that is a typical metabolite of Candida species. The hydroxy group owned by D-arabinitol can function as a reducing agent that can reduce Ag+ to AgNPs. The resulting colloid is further stabilized by the addition of a capping agent. The capping agent used in this study was a combination of chitosan 1%(w/w) and PEG 6000 1% (w/w) (2:1) v/v. The formation of AgNPs causes an increase in the surface plasmon resonance spectra of the colloid solution at a wavelength of 430 nm with a slight blue shift. At the same time, the color of …

Go to article

A Molecularly Imprinted Polymer As Solid Phase Extraction Sorbent For Ketoprofen Determination In Water And Artificial Serum Prior To Hplc, Eli̇f Gürel Özyurt, Ömer Özyurt, Yekta Arya Ölçer Altinsoy, Ahmet Emi̇n Eroğlu, Ezel Boyaci, Talal Shahwan Jan 2022

A Molecularly Imprinted Polymer As Solid Phase Extraction Sorbent For Ketoprofen Determination In Water And Artificial Serum Prior To Hplc, Eli̇f Gürel Özyurt, Ömer Özyurt, Yekta Arya Ölçer Altinsoy, Ahmet Emi̇n Eroğlu, Ezel Boyaci, Talal Shahwan

Turkish Journal of Chemistry

Ketoprofen (KET) is an active pharmaceutical compound that has pain relieving and antipyretic effects. Its determination in body fluids and environmental waters is important due to widespread use of the compound. In this study, a selective and reliable method has been developed for the determination of ketoprofen in water and artificial serum using molecularly imprinted polymers (MIPs) as a solid phase extraction sorbent prior to HPLC-DAD detection. The MIP was synthesized by copolymerization of methacrylic acid (MAA) and trimethylpropane trimethacrylate (TRIM) in the presence of ketoprofen as the template. For the sake of comparison, nonimprinted polymer (NIP) was also synthesized …

Go to article

Thermal Versus Photochemical Tautomerization Of Cytosine And Guanine: A Blyp Computational Study Along The Irc Curves, Tsvetina Cherneva, Vassil Delchev Jan 2022

Thermal Versus Photochemical Tautomerization Of Cytosine And Guanine: A Blyp Computational Study Along The Irc Curves, Tsvetina Cherneva, Vassil Delchev

Turkish Journal of Chemistry

We performed a theoretical study, at the BLYP/aug-cc-pVDZ theoretical level, of the mechanisms of H-transfer between biologically relevant tautomers of cytosine and guanine. The analysis of the ground- and excited state energy barriers of the conversions showed that in some cases they are lower as compared to the ground state reactions. The inclusion of one water molecule as a catalyst in the oxo-amino form of cytosine and guanine drastically changes the mechanism of the reactions in the ground as well as in the excited state. For example, the ground state reaction path of cytosine reduces the energy barrier from 165 …

Go to article

Miscibility And Thermal Behavior Of Poly(Methyl Methacrylate) And Polystyrene Blend Using Benzene As A Common Solvent, Arshiya Iqbal, Jamil Muhammad, Farzana Ahmad, Mohsan Nawaz, Musa Kaleem Baloch, Luqman Mohammad Jan 2022

Miscibility And Thermal Behavior Of Poly(Methyl Methacrylate) And Polystyrene Blend Using Benzene As A Common Solvent, Arshiya Iqbal, Jamil Muhammad, Farzana Ahmad, Mohsan Nawaz, Musa Kaleem Baloch, Luqman Mohammad

Turkish Journal of Chemistry

Polymer blending is one of the advanced technologies to attain polymeric material with tailored properties. In this work, the miscibility of Poly(methyl methacrylate) (PMMA) and Polystyrene (PS) blend in benzene was investigated by employing various techniques such as FTIR spectroscopy, viscosity measurement technique, light scattering techniques, DSC and TGA techniques over an extended range of concentrations, compositions, and temperatures. The results revealed that there exist hydrogen bonding and hydrodynamic interactions which led these polymers to get miscible to a large extent. The compatibility increased with the increasing PS contents or increase in temperature of the system. In addition, the thermal …

Go to article

Synthesis, Characterization, And Antimicrobial Evaluation Of Polyvinylalcohol-Osthol Composite Films, Ishrat Gowsia, Feroz Mir, Javid Banday Jan 2022

Synthesis, Characterization, And Antimicrobial Evaluation Of Polyvinylalcohol-Osthol Composite Films, Ishrat Gowsia, Feroz Mir, Javid Banday

Turkish Journal of Chemistry

Although poly-vinyl alcohol (PVA) has certain mechanical drawbacks such as a weak barrier, it has widely been used in food packaging over the last many years. To increase the suitability of PVA (C2H4O)n and render it ideal for food packaging, a diversity of studies have already been carried out. In the below-mentioned script, we, for the first time, report the use of natural product osthol in making a new composite with PVA for enhancing thermal, physicochemical, and antimicrobial properties. The significant aim of the report is the insertion of osthol (C15H16O3 …

Go to article

Moonshots, Matthew Wansley Jan 2022

Moonshots, Matthew Wansley

Articles

In the last half-century, technological progress has stagnated. Rapid advances in information technology disguise the slow pace of productivity growth in other fields. Reigniting technological progress may require firms to invest in moonshots—long-term projects to commercialize innovations. Yet all but a few giant tech firms shy away from moonshots, even when the expected returns would justify the investment. The root of the problem is corporate structure. The process of developing a novel technology does not generate the kind of interim feedback that shareholders need to monitor managers and managers need to motivate employees. Managers who anticipate these agency problems invest …

Go to article

Uniformly Convergent Finite Difference Method For Reaction-Diffusion Type Third Order Singularly Perturbed Delay Differential Equation, Rajendran Mahendran, Veerasamy Subburayan Jan 2022

Uniformly Convergent Finite Difference Method For Reaction-Diffusion Type Third Order Singularly Perturbed Delay Differential Equation, Rajendran Mahendran, Veerasamy Subburayan

Turkish Journal of Mathematics

A class of third order reaction-diffusion type singularly perturbed ordinary delay differential equations is considered in this article. A fitted finite difference method on Shishkin mesh is suggested to solve the problem. Moreover, we present a class of nonlinear problems. An error estimation is obtained based on the maximum norm and it is of almost first order convergence. Numerical results are given to support theoretical claims.

Go to article

Discrete Impulsive Sturm-Liouville Equation With Hyperboliceigenparameter, Turhan Köprübaşi, Yelda Aygar Küçükevci̇li̇oğlu Jan 2022

Discrete Impulsive Sturm-Liouville Equation With Hyperboliceigenparameter, Turhan Köprübaşi, Yelda Aygar Küçükevci̇li̇oğlu

Turkish Journal of Mathematics

Let $L$ denote the selfadjoint difference operator of second order with boundary and impulsive conditions generated in $\ell _{2}\left( %TCIMACRO{\U{2115} } %BeginExpansion \mathbb{N} %EndExpansion \right) $ by \begin{equation*} a_{n-1}y_{n-1}+b_{n}y_{n}+a_{n}y_{n+1}=\left( 2\cosh z\right) y_{n}\text{ },% \text{ }n\in %TCIMACRO{\U{2115} } %BeginExpansion \mathbb{N} %EndExpansion \setminus \left\{ k-1,k,k+1\right\} , \end{equation*}% \begin{equation*} \begin{array}{c} y_{0}=0\text{ }, \\ \left\{ \begin{array}{c} y_{k+1}=\theta _{1}y_{k-1} \\ \bigtriangleup y_{k+1}=\theta _{2}\bigtriangledown y_{k-1} \end{array}% \right. ,\text{ }\theta _{1},\theta _{2}\in %TCIMACRO{\U{211d}}% %BeginExpansion \mathbb{R}, %EndExpansion \end{array}% \end{equation*} where $\left\{ a_{n}\right\} _{n\in %TCIMACRO{\U{2115} } %BeginExpansion \mathbb{N} %EndExpansion },$ $\left\{ b_{n}\right\} _{n\in %TCIMACRO{\U{2115} } %BeginExpansion \mathbb{N} %EndExpansion }$ are real sequences and $\bigtriangleup ,\bigtriangledown $ are respectively forward …

Go to article

Existence Of Solutions For An Infinite System Of Tempered Fractional Order Boundary Value Problems In The Spaces Of Tempered Sequences, Khuddush Mahammad, Rajendra Prasad Kapula, Leela Doddi Jan 2022

Existence Of Solutions For An Infinite System Of Tempered Fractional Order Boundary Value Problems In The Spaces Of Tempered Sequences, Khuddush Mahammad, Rajendra Prasad Kapula, Leela Doddi

Turkish Journal of Mathematics

This paper deals with infinite system of nonlinear two-point tempered fractional order boundary value problems $$ \begin{aligned} {}^\mathtt{RL}_{~0}\mathbb{D}^{δ_2,\ell}_\mathtt{z}\Big[\mathtt{p}_\mathtt{j}(\mathtt{z})&{}^\mathtt{RL}_{~0}\mathbb{D}^{δ_1,\ell}_\mathtt{z} \vartheta_\mathtt{j}(\mathtt{z})\Big]=λ_\mathtt{j}\varphi\big(\mathtt{z},\vartheta(\mathtt{z})\big),\, \mathtt{z}\in[0,\mathtt{T}], δ_1,δ_2\in(1,2),\\ &\hskip0.25cm\vartheta_\mathtt{j}(0)=\lim_{\mathtt{z}\to0}\left[{}^\mathtt{RL}_{~0}\mathbb{D}^{δ_1,\ell}_\mathtt{z}(e^{\ell\mathtt{z}}\vartheta_\mathtt{j}(\mathtt{z}))\right]=0,\\ &e^{\ell\mathtt{T}}\vartheta_\mathtt{j}(\mathtt{T})=\lim_{\mathtt{z}\to\mathtt{T}}\left[{}^\mathtt{RL}_{~0}\mathbb{D}^{δ_1,\ell}_\mathtt{z}(e^{\ell\mathtt{z}}\vartheta_\mathtt{j}(\mathtt{z}))\right]=0, \end{aligned} $$ where $\mathtt{j}\in\{1,2,3,\cdot\cdot\cdot\},\,\ell\ge 0,$ ${}^\mathtt{RL}_{~0}\mathbb{D}^{\star,\ell}_\mathtt{z}$ denotes the Riemann--Liouville tempered fractional derivative of order $\star\in\{δ_1,δ_2\}$, $\vartheta(\mathtt{z})=\left(\vartheta_\mathtt{j}(\mathtt{z})\right)_{\mathtt{j}=1}^{\infty},$ $\varphi_\mathtt{j}:[0,\mathtt{T}]\to[0,\mathtt{T}]$ are continuous and we derive sufficient conditions for the existence of solutions to the system via the Hausdorff measure of noncompactness and Meir-Keeler fixed point theorem in tempered sequence spaces.

Go to article

On Bounded Solutions Of A Second-Order Iterative Boundary Value Problem, Safa Chouaf, Ahleme Bouakkaz, Rabah Khemis Jan 2022

On Bounded Solutions Of A Second-Order Iterative Boundary Value Problem, Safa Chouaf, Ahleme Bouakkaz, Rabah Khemis

Turkish Journal of Mathematics

In this article, we investigate a second-order iterative differential equation with boundary conditions. The use of the principle of contraction mappings and the Schauder's fixed point theorem allows us to prove some existence and uniqueness results. Finally, an example is given to check the validity of our findings, which are new, and complete some published manuscripts to some degree.

Go to article

Solvability Of Gripenberg's Equations Of Fractional Order With Perturbation Term In Weighted $L_P$-Spaces On ${\Mathbb{R}}^+$, Mohamed M. A. Metwali Jan 2022

Solvability Of Gripenberg's Equations Of Fractional Order With Perturbation Term In Weighted $L_P$-Spaces On ${\Mathbb{R}}^+$, Mohamed M. A. Metwali

Turkish Journal of Mathematics

This article deals with the solvability of Gripenberg's equations of fractional order with a perturbation term in weighted Lebesgue spaces on ${\mathbb{R}}^+=[0,\infty)$ via the fixed point hypothesis and the measure of noncompactness. The uniqueness of the solutions for the studied problem is discussed. An example is included to validate our results. The results presented in the article extend and generalize some former results in the available literature.

Go to article

Solving Nonlinear Integro-Differential Equations Using Numerical Method, Nedjem Eddine Ramdani, Sandra Pinelas Jan 2022

Solving Nonlinear Integro-Differential Equations Using Numerical Method, Nedjem Eddine Ramdani, Sandra Pinelas

Turkish Journal of Mathematics

The aim of this paper is to establish conditions for the existence and uniqueness of the solution of a nonlinear integro-differential equation. Moreover, it is to propose a quadrature method in order to find an approximate solution and establish the convergence of the method. We conclude by providing the algorithm and some numerical simulation to confirm our theoretical results.

Go to article

A Discussion On The Existence And Uniqueness Analysis For The Coupled Two-Term Fractional Differential Equations, Sachin Kumar Verma, Ramesh Kumar Vats, Avadhesh Kumar, Velusamy Vijayakumar, Anurag Shukla Jan 2022

A Discussion On The Existence And Uniqueness Analysis For The Coupled Two-Term Fractional Differential Equations, Sachin Kumar Verma, Ramesh Kumar Vats, Avadhesh Kumar, Velusamy Vijayakumar, Anurag Shukla

Turkish Journal of Mathematics

This paper mainly concentrates on the study of a new boundary value problem of coupled nonlinear two-term fractional differential system. We make use of the theories on fractional calculus and fixed point approach to derive the existence and uniqueness results of the considered two-term fractional systems. To confirm the application of the stated outcomes, two examples are provided.

Go to article

On Stability And Oscillation Of Fractional Differential Equations With A Distributed Delay, Limei Feng, Shurong Sun Jan 2022

On Stability And Oscillation Of Fractional Differential Equations With A Distributed Delay, Limei Feng, Shurong Sun

Turkish Journal of Mathematics

In this paper, we study the stability and oscillation of fractional differential equations \begin{equation*} ^cD^\alpha x(t)+ax(t)+\int_0^1x(s+[t-1])dR(s)=0. \end{equation*} We discretize the fractional differential equation by variation of constant formula and semigroup property of Mittag-Leffler function, and get the difference equation corresponding to the integer points. From the equivalence analogy of qualitative properties between the difference equations and the original fractional differential equations, the necessary and sufficient conditions of oscillation, stability and exponential stability of the equations are obtained.

Go to article

First Prev Next Last