Volume 19 – Issue 3

The present paper presents the Fermi-Walker derivative on the spherical indicatrices of a space curve according to the quasi frame. Firstly, we mention about the fundamentals of the Fermi-Walker derivative and parallelism. Then, we give some geometric properties of these concepts according to the quasi frame. Finally, we give the Fermi-Walker derivative on the spherical indicatrices of a space curve according to the quasi frame which is our main subject. Moreover, we give an Appendix in which we present a method about how to solve a homogenous normal linear system of differential equations.

The paper is concerned with the ruled surfaces generated by the main curve and its natural lift curve in dual space. Then it gives a detailed analysis of ruled surfaces for dual spherical curves of natural lift curve. Striction curves and distribution parameters of these ruled surfaces are calculated. The developability condition is examined by using obtained results. Finally, some examples are given to support the main results.

In this study, we first obtain infinite sums derived from the reciprocal of the Gaussian Lucas sequence using the Binet formula and some properties. Then, we express the infinite sums of these reciprocals in terms of the Lambert series.

The aim of this paper is to present solution of the fractional Fokker Plank equation (FFPE) using fractional power series (FPS) method. The fractional derivatives are considered in Caputo sense, via MATLAB for providing the numerical and graphical solutions.

In the present work, some mathematical models of non-linear types for first order integro-differential equation and system of fractional order are analytically tackled by the fractional VIM. The fractional derivative is considered in Caputo Fabrizio sense involving an exponential function and has interesting properties. The illustrative numerical examples show that the solution approach to the classical solutions as the order of the fractional derivative increases. The graphs obtained by generalized results are also plotted by using symbolic software Maple. Comparison of our approximate solution with the exact numerical results of the problems is presented to illustrate the reliability and efficiency of the method.

Dirichlet problem is one of the major problems of the theory of partial differential equations and occurs in several physical applications. In this study, a new numerical technique based on the Pell polynomials and collocation points is offered to obtain the approximate solution of Dirichlet problem for linear partial differential equations with variable coefficients. The method transforms the equation along with Dirichlet boundary conditions into a matrix equation with the unknown Pell coefficients by means of collocation points and operational matrices. The solution of this matrix equation yields the Pell coefficients of the solution function. Thereby, the approximate solution is obtained in the truncated Pell series form. Also, some examples together with error analysis technique based on residual functions are expensed to demonstrate the validity and applicability of the present method; the comparisons are fulfilled with existing results.

In this paper, Pseudo-Jacobi matrix polynomials are introduced, starting from the hypergeometric matrix representation. Some properties of these matrix polynomials such as generating matrix functions, Rodrigues’ formula, matrix recurrence relations and expansions are deduced.

In this paper, we define the generaziled Lucas sequences and the Pell-Lucas sequences. Further we give Binet-like formulas, generating function, sums formulas and some important identities which involving the generalized Lucas and Pell-Lucas Numbers

In this paper, we implemented an Generalized (G^’/G) – expansion method for some soliton wave solution sixth-order Ramani equation and new Konno-Oono equation system. These solutions are hyperbolic function solutions, trigonometric function solutions,
exponential function solutions and rational function solutions. We also saw that the solutions provided the equation using Mathematica 11.2. In addition, graphs of some solutions and numerical explanations of these graphs were given. Recently, this method has been studied for obtaining exact travelling wave solutions of nonlinear partial differential equations

Although moss-based biomonitoring of environmental pollutants (heavy metals, POPs, reactive nitrogen, and sometimes other items) is well established after 50 years of a history starting in Scandinavia, the method now faces a crisis also in terms of funding. This latter is due to the assumption that precision and reproducibility of this biomonitoring method are too poor to provide information on small recent changes of situation well after the large changes had occurred, that is, around 1990. In addition, moss-monitoring requires that conditions where mosses can live and grow be constantly kept over a longer period of time; measurements in the dark or at sites where there are high levels of herbicides, radioactivity, acids, etc. cannot be accomplished at all; proper identification of used moss species is crucial, too. Hence moss-monitoring should be supplemented by other methods which – unlike passive biological or synthetic filters of atmospheric deposition – can provide information on local transport (both by airborne deposition and underground biological uptake or precipitation, plus reductive dissolution of sulfates) at ecotones such as the water/sediment interface at bottom of water-bodies or at some shore. Studies of adsorption to chitin, which originally had been applied for fractionation of radioactive waste and for withholding trace concentrations of heavy metals from wastewaters, can fill this gap as more robust “dead” (grafted) chitin is used. Adsorption is fast, and even minute traces of analytes can be recovered. Analytics are cheap and straightforward, requiring no digestion of samples. In understanding the data, some calibration line(s) for partition of both di- and trivalent metal ions (best: such which are not involved in biological processes) between water- and sediment-exposed chitin samples are constructed then to identify “deviations” from this expectation. These can be due to biological uptake of trace elements (Ni by methanogenes, plants, Mo, certain more “exotic” bioelements), precipitation (Fe, Mn), reductive dissolution (sulfates of Ba, Pb, Eu exposed to ascending CH4) or, of course, atmospheric or aquatic pollution from above. As a rule, chitin-related partition of toxic nonmetals (As, Se) does respond to different environmental conditions, vegetation covers less than metal ions will do. Grafted chitin can be fitted to robots like drones transporting it to hazardous sites where organisms (arthropods, lichens) would not survive. Of course, data of this kind can be combined with pieces of information from biomonitoring (are there organisms controlling transport of certain elements?, is there eutrophication of open waters?) and biogeochemistry.

The purpose of this study is to find new alternative methods for removing dyes (methylene blue dye) regularly present in wastewater by using adsorbent materials obtained from vegetable waste (beech and fir wood sawdust) due to their low-cost adsorbent properties. The used dye used as model was methylene blue and the effect of the initial concentration (30 – 50 mg/L), the adsorbent dose of the support material (2-10 g) and the effect of the initial pH of the solution (3, 5, 7, 9, and 11) were investigated. The optimization of the volume and flow rate was investigated, too. The maximum efficiency of removal of methylene blue dye present in aqueous environments it was 97%. The mathematical modelling of the Langmuir, Freundlich and Temkin adsorption isotherms using the experimental results, was used and properly discussed, demonstrating that Langmuir model is the most suitable for the experimental results.

Every year in our country, especially in the coastal zone of the Black Sea due to the intensive food processing and canning of fish and seafood from fisheries and markets, a large amount of raw material is produced, of which more than half consists from crab shells. Crab shells are a rich source of chitin, chitosan and cellulose. In order to obtain chitosan the procedure was started with the chemical extraction of chitin from the stone crab shells of the species Pachygrapsus mormoratus, from the Black Sea, because it is a species of crustaceans which are abundant on the Black Sea coast. In obtaining the chitin raw material were followed certain steps, in a chronological order, namely: the step of deproteinization, demineralization, decolorization and then converted the chitin into chitosan by a strong alkaline deacetylation method. For the characterization of chitosan physico-chemical studies were conducted in order to determine the parameter values. FTIR analyzes were performed to confirm the presence of the extracted chitosan. The results confirm and support the use of chitosan extracted from crab stone Pachygrapsus mormoratus for obtaining pharmaceutical biomaterials.

There are several types of biomass that have been known to reduce metals concentrations from aqueous media. This study focused on the effect of Jatropha curcas L. latex as a potential biosorbent of heavy metals (Cadmium, Lead and Mercury) in contaminated water. The selection was based on the fact that these metals have known detrimental effect to health once the concentration exceeds the maximum allowable limit. The analysis of heavy metals concentrations were conducted using standard laboratory procedures using Atomic Absorption Spectrometer. Results of the study revealed that in the 24 hours post treatment, noticeable increase in pH, discoloration and precipitation were recorded slightly increased at electrical conductivity at 379 µS/cm. While there were no recorded decrease on the level Cadmium and Lead the concentration of Mercury has substantially decreased from 2.72 µg/mL to 0.07µg/mL. The overall findings clearly indicate the potential of Jatropha curcas L. latex to adsorb and precipitate the heavy metal Mercury from aqueous media. This may be due to the presence of phytochemical tannins. The metal adsorbent capacity of the plant extract was found at 600 µg/ml of dissolved Mercury.

This article proposes new rheological models for soybean oil. The purpose of this study was to find an exponential dependence between temperature and the logarithm dynamic viscosity of soybean oil, using one equation. Equation constants ln η0, A1 and t1 were determined by fitting a suitable correlation. The soybean oil investigated using a Haake VT 550 Viscotester at shear rates ranging between 3 and 120 s-1 and measuring viscosities from 104 to 106 mPa·s when the HV1 viscosity sensor is used. Soybean oil logarithm of dynamic viscosity decreases with increasing temperature at constant shear rate. Plotting the logarithm of dynamic viscosity as function of temperature shows an exponential decline.

In attempt to avoid prosthetic problems and possible side effects that may occur in long-term bisphosphonate treatment, a solution commonly studied in recent years is local bisphosphonate release. Thus, a higher dose can be administered in the region of interest with positive effects on reduction bone loss in the periprosthetic area, but especially on osteointegration reduction time and acceleration of prosthesis component secondary fixation. On the other hand, stable fixation is also achieved in the case of osteoporotic bone. In the present paper, we have proposed to obtain implant type structures by deposition of alendronate-hydroxyapatite compositions (HA-AL) on titanium metal substrates. The deposition of the composite directly on the metallic component was accomplished by pulsed laser evaporation technique (MAPLE).

Essential oils are now getting more importance in food industry, being used to prevent food spoilage and to promote food preservation. The present study was carried out so as to evaluate the antioxidant and antimicrobial effect of the essential oils of two aromatic plants, namely Cymbopogon citratus (Lemongrass) and Syzygium aromaticum (Clove), and to investigate a possible synergistic effect of the combination of these oils. The evaluation was performed for individual oils and the combination of the two oils in 1:1, 2:1 and 1:2 ratios, against two bacterial pathogens, namely Escherichia coli and Staphylococcus aureus. The study showed promising results for the use of Cymbopogon citratus and Syzygium aromaticum oils, as antioxidant (individually and in combination) and antimicrobial (individual) agents. Cymbopogon citratus and Syzygium aromaticum oils are good candidates to the biopreservation of foods.

The regular wheat and Spelta wheat are the most commonly used grains in human existence. In this paper, wheat and Spelta bran extracts were used AgNO3 was added in order to obtain silver nanoparticles (AgNPs). For each type of bran, vitamins content (ascorbic acid, niacin, pyridoxine, thiamine, riboflavin) were determined by HPLC, in order to evaluate qualitative and quantitative the vitamins concentrations. FTIR, Raman and SEMEDS techniques were used to characterize the extracts with AgNO3, and AgNPs generated insitu.

The study presents the effect of adding p-tert-butylcalix[4]arene, benzo ether crowns and their equimolecular mixture in the organic phase on the interfacial tension for the chloroform water interface. It was found that addition of macrocyclic ligands to the organic phase has different effects on the interfacial tension. The higher the number of oxygen atoms in the ethereal ring of the benzo crown ethers, the higher the values of interfacial tension, while same modification of the ethereal ring produces an opposite effect in the case of amino benzo ethers, indicating different arrangements of molecules in the interface.The simultaneous presence of p-tert-butylcalix[4]arene and benzo crown ethers in the interface leads, in some situations, to significant changes in the interfacial tension values, a phenomenon explained by the modification of the macrocyclic ligands assembly in the interface. Also, composition of the aqueous phase influences the value of measured interfacial tension, type of the alkaline cation from the aqueous solution leading to different behavior of macrocyclic ligands in the interface.

In the last 25 years, Romania has undergone a large industrial restructuring, which has resulted in the closure of mines or the diminution of mining operations. However, the mining activities have caused negative impacts both on the environment and on the population. The present study summarizes the situation of the mining activity in the south area of the Banat Montains (Romania) and presents the effects produced by the mining exploitation on the environmental factors but also of the wellness of area`s population

The current endeavor is communicated to perceive the characteristics of tangent hyperbolic fluid confined by a deformable sheet in the existence of both variable thermal conductivity and magneto hydrodynamics. An exertion is reported to calculate the numerical solutions of tangent hyperbolic fluid. Mathematical model is contrived in the embodiment of PDEs and after that renovated into ODEs by implementing self-felicitous transformations. Furthermore the obtained ODEs are simplified by utilizing Bvp4c (MATLAB package). Numerical computations of Nusselt number, skin friction, temperature and velocity profiles for miscellaneous values of involved parameters are manifested via graphs and tables. A comparison of contemporary outcomes with existing published work has been taken into account which shows excellent agreement of results.

Fuzzification of multilayer perceptron is proposed using generalized fuzzy numbers and an extension for the activation function of fuzzy neurons. All the operations take place in the generalized fuzzy numbers framework using the function principle. A new learning based on gradient methods is proposed and experimental results are also presented

Magnetic flux generated by neodymium-iron-boron magnets of three different configurations are calculated and compared by using COMSOL Multiphysics simulation. For a magnetic ring, the substantial flux density of 0.6-0.7 T is obtained in the bore and the edge. The values are increased beyond 1 T in the gap between inner and outer concentric rings in the second structure. The magnetic flux density is fairly uniform in the circumferential direction. Finally, moderate fields around 0.6 T in spaces between magnetic bars arranged into concentric arrays can be utilized. In this structure, the magnetic flux density along the radial direction measured from the center of the ring peaks at two distances corresponding to two arrays of magnets. These different profiles of magnetic field can be implemented in devices and experiments of different requirements.

Altitude decompression sickness can be mathematically modeled by analytic
expressions but these models are actually guessed initially by the authors based on
experience and data analysis. A systematic alternative approach is developed in this paper, a
solution based on evolutionary approach, the genetic programming. The measure of fitness is
evaluated by maximum likelihood estimation and experimental results are presented.

One of the major issues faced by chronic patients is real-time monitoring of vital parameters and early warning of emergency medical units when these parameters go out of the normal range. Most chronic patients suffer from heart disease. In this regard, the present paper introduces a system of monitoring vital parameters, arterial blood pressure and heart rate with 3 EKG electrodes and a GPRS / GSM communicator controlled by an Arduino Uno board. Upon the occurrence of abnormal values of these parameters that may be dangerous to the life of the person in question, the data transmission device that sends a GSM alarm signal to the surveillance medical service to which the patient is assigned is activated. To validate the actual EKG signals, a heart rate measuring device based on photoplethysmography was used. The experimental results show that the projected system has low power consumption, so the lifetime of the power battery is high and the time of transmitting the alert signal of the tenths of a second