Mathematics
Chemistry
Physics
Mathematics
In this study, the distance matrix and the distance energy of power graphs on cyclic groups and dihedral groups are considered. Furthermore, some bounds for the largerst eigenvalue of the distance matrix and the distance energy are found. Also, some results are obtained by using these bounds.
In this work, four variants of time-fractional nonlinear Caputo-type Newell– Whitehead–Segel (NWS) problem are solved by fractional variational iteration method. This equation results as mathematical model of many important physical reaction-diffusion processes and pattern formation theory in diverse fields of chemical engineering, mechanical engineering, bio-engineering, biology and fluid mechanics, and the numerical treatments of these models are of great scientific significance and practical values. The received outcomes and plotted graphs express that the carried out technique is unpretentious, competent, and easily applicable for nonlinear fractional-order Partial differential equations (PDEs).
In this study, using Darboux vector of an isotropic curve given by Şemin in [1], we give a characterization of isotropic Darboux helices in the complex space 3 C . We show that an isotropic curve to be a Darboux helix has to have a constant pseudo curvature. We obtain the position vector of a nonzero fixed direction U. Then we give some characterizations related to the main theorem.
Present study introduces a new class of strongly harmonic functions and its relationship with harmonically h – convex functions. Some new HermiteHadamard type inequalities for class of strongly harmonic h – convexare also established which generalizes previous results.
Formulas and identities involving many well-known special numbers (such as Fibonacci, Lucas, Pell, Pell-Lucas, Jacobsthal, Jacobsthal-Lucas, Horadam, and so on) in the algebras play important roles in themselves and in their diverse applications. Various families of recurring numbers have been established by a number of authors in many different ways. This article presents the results of some new research on a new class of recurring integer sedenion numbers that unite the characteristics of the sedenion numbers and the Horadam numbers
. In this paper, we implemented an improved tanh function Method for some exact solutions of fifth order equation of Burgers hierarchy. This method is presented by Chen and Zhang.
This study is concerned with finding the threshold parameter that determines the status of infected individuals in a discrete-time SIS disease model transmitting the infection to other individuals and determining the number of individuals catching the infection. In this study, we firstly examined the equilibrium points of the model, and we determined the presence of a single positive equilibrium point depending on the number of diseased individuals. Then, based on the threshold parameter, we investigated the local asymptotic stability conditions. Moreover, we provided a topological classification of these equilibria. Finally, we obtained the condition providing the emergence of “period-doubling bifurcation” in the given model. The theoretical results that were obtained were verified with numerical examples by using the Mathematica software.
The purpose of this study is to examine the function sequences and series in the non-Newtonian real numbers. Firstly, the information about the studies that are done until today and the application areas, was briefly given. Non-Newtonian calculus was introduced which is an alternative to the classical calculus, definitions, theorems and properties were given. *-Function sequence, *-function series, *-pointwise convergence and *-uniform convergence were introduced and theorems were proven which are exposed important differences between *-pointwise convergence and *-uniform convergence. In addition, *-convergence tests such as *-Cauchy criterion and *-Weierstrass M-criterion were obtained. The relationship between *-uniform convergence of the *-continuity, *-integral and *-derivative was examined respectively.
In this paper, we study a new construction of curves by normal Fermi-Walker parallelism and derivative with modified frame. Finally, we give normal Fermi-Walker parallelism and derivative for a focal curve according to modified frame.
The Apriori algorithm is considered a classic in the association rules extraction field. This algorithm makes recursive searches in a dataset looking for frequent sets that satisfy given minimum support. Apriori has several properties to optimize its performance, such as reducing the number of generated itemsets and its parallelization by multiple processors. These features have led to the emergence of several studies that present parallel versions of Apriori. However, these proposals do not explore the heterogeneous capabilities of each machine, which causes a significant part of the algorithm’s processing time to be spent on I/O processes and not exactly on the execution of the algorithm. In this sense, this study proposes a mathematical modeling of the Apriori algorithm in which heterogeneous machines are considered. The findings identified a better performance of this algorithm when compared to the original and parallel versions of Apriori, but in which all processors are considered homogeneous. The findings reveal the time reducing rate increases with the growth in the number of itemsets and the number of considered processors.
Chemistry
Preparation of charcoal from organic waste by-product of Jackfruit (Artocarpus heterophyllus Lam.) is one of the most efficient tool and advantage of waste management that have technological, economic, and environmental impact. The purpose of present study is to develop activated charcoal for the removal of toxic metals from aqueous solution. Batch adsorption experiments were carried out to investigate the suitability of activated and non-activated charcoal in removing Lead and Cadmium. Adsorption/Sorption processed to remove heavy metals accumulation from aqueous environment is primary concern due to health impact upon chronic exposure. Fourier-transform infrared spectroscopy (FTIR) and Scanning Electron Microscope (SEM) were used to characterize prepared activated and non-activated charcoal from Jackfruit peel. Rapid and Efficient adsorption/Sorption properties of prepared charcoal were tested against Cadmium (Cd) and Lead (Pb). FTIR and SEM characterization revealed functional groups ─OH, C─H, and C═C stretches in activated and non-activated charcoal with pore size of 2.86 – 10.0 µm and 2.96 – 14.7 µm, respectively. Rapid adsorption/sorption capacity demonstrated 87.39±3.5173% and 84.30±2.9166% efficiency for activated and non-activated charcoal, respectively. Statistical analyses showed significant difference (p
The chemical composition of rye flour can be a good indicator of the bread quality. In this study, the rye flour was mixed with wheat flour in ratios of 10%, 25% and 50%. The chemical parameters (moisture, ash, fat contents and alkalinity) and the physical parameters (diameter, thickness, weight and spread factor) of the biscuits have been analysed. The results of the chemical analysis showed variable results, such as the increase of the fat and ash contents, and the decrease of the moisture content and of the alkalinity. In terms of physical characteristics, the samples generally presented some differences. The Pearson coefficient showed that there is a strong correlation between the width of the biscuits and the proportion of added rye flour, and a weak correlation between the spread ratio and the amount of rye flour that is used.
Electrolysis of water is a promising option to produce hydrogen with high purity using solar energy. The performance of electrolysis of water is influenced by several parameters. The main objective of this work is to study the production of hydrogen through electrolysis of water on testing new cathode alloy: Zn-Fe. Using experimental design, a regression function relating the volume of hydrogen produced and three factors: input voltage, input amperage and electrolyte concentration was developed. The results revealed that all factors studied have a positive effect on volume of hydrogen produced. The interactions between these factors are not negligible and must be taken into account during the production of hydrogen. The maximum volume 14.2 mL of H2 at 4 min is obtained when the three factors are at their high levels: 5 V, 0.5 A and 30 g/L of NaOH
The total phenols content of alcoholic extractive solution of mint (Mentha piperita) was examined using Folin-Ciocâlteau method and the composition of its phenolic components was investigated by adapted USP30 HPLC method. The analyzed mint macerate exhibits high total phenolic content amoung which three major phenolic compounds were identified: gallic acid, chlorogenic acid and caffeic acid. The antioxidant activity of Mentha alcoholic extractive solution was evaluated using DPPH Radical Scavenging test.
The aim of the study was to investigate rheological properties of soybean oil. The soybean oil was investigated using a Haake VT 550 Viscotester at shear rates ranging between 3 and 120 s-1 and measuring viscosity from 104 to 106 mPa·s when the HV1 viscosity sensor is used. The temperature was ranged between 40 and 90oC and the measurements were made from 10 to 10oC. The accuracy of the temperature was 0.1 °C. This paper proposes two new relations of dependence of log dynamic viscosity on the 1/T shear rates between 3.3 and 120 s-1 . The constants A, B, and C were determined by Origin 6.0 software by fitting exponential or polynomial curves which were obtained from experimental data. The two proposed relationships give correlation coefficients close to one.
Black Sea seaweed is an important marine resource that can bring many benefits. To use algae for various purposes, preliminary studies are required to know their composition. Preliminary studies are presented in this paper to identify bioactive compounds which hold therapeutic interest. Three species of algae were analysed: green algae represented by Ulva lactuca, brown algae represented by Cystoseira barbata and red algae represented by Ceramium rubrum. Seaweeds were harvested from four harvesting stations located along the Romanian Black Sea coast in two consecutive seasons (autumn 2018 and spring 2019). Following the analysis of the physico-chemical results, sulfate compounds, carbohydrates and total dietary fibers were obtained in appreciable quantities. Comparisons were made between the average values obtained in the two seasons. It is found that in the spring season the percentage values for sulfate and carbohydrates contained in all the algae tested are lower than those obtained in the autumn season, which is due to the influence of environmental conditions, but also of the stage of aquatic plant development. The phytochemical analysis performed in the preliminary studies allowed the identification of compounds with important actions for therapeutic purposes. Preliminary studies on seaweed confirm that permanent monitoring of seaweed compositions makes it possible to collect clean algae from their natural environment and use them for bioactive compounds with applications in the medical, pharmaceutical, cosmetic or nutritional industries.
This document Granite quarries in Aswan, south of Egypt, have many rock paintings and engravings. This rock art in Aswan’s granite quarries is exposed to many weathering factors that threaten its survival. To protect these arts, the research focused on a comparative study to evaluate the application of certain reinforcing materials such as Paraloid B44, Paraloid B48, Estel 1000 and SILRES® BS OH 100 to strengthen crumbling rock. Examination and analysis methods such as polarized microscopy (PM), scanning electron microscopy and analysis with energy-dispersed X-ray unit (SEM-EDX) and X-ray diffraction analysis (XRD) have been used to determine the chemical and mineral composition of the rock and the degradation and damage to rocky art. These treatments were evaluated after artificial aging by scanning electron microscopy. The results show that treatment with Estel 1000 is suitable for studied rock paintings and engravings.
5α –reductase 2 is an interesting pharmaceutical target for the treatment of several diseases, including prostate cancer, benign prostatic hyperplasia, male pattern baldness and hirsutism. Quantitative structure-activity relationship (QSAR) analysis has been carried out for the prediction of inhibitory activity of a set of 4-X-17-Y-4-Azaandrost-3-ones as 5α –reductase 2 inhibitors. Bi-dimensional images were applied to calculate some pixels and partial least squares (PLS) algorithm was applied to QSAR modelling of 5α –reductase inhibitors. In this paper, we surveyed the effect of variable selection by application of genetic algorithms (GAs) for the PLS model. The GAs is very helpful in the variable selection in modeling and selecting the subset of pixels with the low prediction error. Pre-processing methods such as orthogonal pixel correction (OPC) were also used to provide the suitable input for modeling. These models were applied to the prediction of the molecules inhibition, which were not in the modeling procedure. The resulted model showed a high predictive ability with the root mean square error of prediction (RMSEP) of 0.52, 0.35 and 0.94 for PLS, GA-PLS and OPC-GA-PLS models respectively. Furthermore, the proposed QSAR model with the OPC-GA-PLS method was developed to predict the inhibitory activity of the new compounds.
The Oravita Depression is an area with a specific climate, characterized by the presence of local catabatic wind, called „Cosava”. The present study investigates the impact of the wind Cosava and the effects produced by that on the socio-economic activities, especially on the local agriculture. At the same time, it is desired to investigate the opinion of the locals regarding the impact felt by manifesting this phenomenon in the area, respectively, the possibility of implementing a risk warning program for phenomena caused by intensifications of the wind.
Physics
In the present problem an analytical periodic solution of an electrically conducting viscous, incompressible fluid in a slip flow through porous medium bounded by two parallel infinite porous horizontal plates is studied. The lower plate is motionless and the upper one is oscillatory in time about a costant mean. The fluid motion is in effect of a constant injection/suction, and a magnetic field perpendicular to the plates. The unsteady problem is solved analytically and solution of transient velocity, the amplitude and phase of the skin friction at the stationary plate are found.
The solution of nonlinear mathematical models has much importance and in soliton theory their worth has increased. In present article, a research has been made of nonlinear Jimbo Miwa and Kadomtsev-Petviashvilli equations, to discuss behavior of these equations and to attain travelling wave solutions. Exp(-δ(ξ))-expansion technique is used to construct soliton wave solutions. Wave transformation is applied to convert problem in the form of ordinary differential equation. The drawn-out novel type outcomes pay an essential role in the transportation of energy. It is noticed that under study approach is extremely dependable and it may be prolonged to further mathematical models signified mostly in nonlinear differential equations
It is found that in Tl (InS2)_1-x (FeSe2)_x crystals and it is characteristic sequence of phase transitions, for TlInS2, manifested in the form of anomalies in the temperature dependences of δ = f (T) and ε = f (T). It is shown that as the values of x laver, the phase transition temperatures decrease, and the temperature range for the existence of an incommensurate phase a bit increases. Information has been was obtained on the temperature dependence of δ (T), the width of the forbidden band from the spectral distribution of intrinsic photoconductivity, and the magnitude of maximum spectral photo sensitivity σc^ max/σ_T for the samples studied
This paperwork is focused on highlighting the potential of reusing the local decommissioned water towers, to serve as hydroelectric energy buffers, on demand. It is a known fact that most water towers, worldwide, built either for municipality community or for industrial service, are left to decay, destroyed, or even converted as landmarks, restaurants and lodgings, due to the upgrade to a modern water distribution system
The objective of this paper it is to produce magnetic sensors with thin Ni-Cu layers with GMR, sputtered on SiO2 substrate, which could be used as magnetic field sensors. Determination of the thickness and uniformity of the magnetic sensor layers it is done by optical microscopy and atomic force microscopy (AFM) for different areas. Finally, measurements were made using the MF100 AC/DC magnetometer and the experimental results were processed. As a magnetic field source, we used a ferrite ring magnet, Y35, with 6 kg force (about 58.8 N).
On-premises Data Centers have constant high energy demands, they represent an olways-on load at buildings energy balance level. By separating such a load in behind a microgrid system with storage and photovoltaic generation, important CO2 reductions could be achieved. This paper presents the results of such an implementation analyzed from a technical and economical point of view. The pilot installation is analized based on a 3-year data set, measurements consisting in: consumption, PV production, imported energy and storage operation. The pilot achieved for 2017 a 59.66% PV energy coverage from its total usage, thus a financial economy of estimated 3300 Euro from the energy bills. Based on the simulation results the Return of Investment is at the end of the operational lifetime of the installation considering no state incentives nor energy export sold back to the grid. A total of 22.4 T/year CO2 emissions are avoided.