TMs Equation Research Articles

Highly efficient Zinc Oxide nanostructure based gas sensor for domestic application

In this work, Zinc Oxide (ZnO) nanorods with high surface to volume ratio were fabricated through the hydrothermal synthesis process on a glass slide and highly conductive alumina ceramic based gold interdigitated electrode (IDE). The ZnO nanorods structure on substrates were characterized through X-ray diffraction (XRD) and UV absorption spectroscopy followed by growth verification by Scherrer’s equation. The sensitivity characterization of fabricated sensor was determined for 2000 ppm and 4000 ppm natural gas in the air through high resistance electrometer at room temperature. The 2000 ppm concentration of gas shows 11.3% sensitivity, response time of 66 seconds and recovery time of 92 seconds to the sensor. The 4000 ppm concentration of gas shows 64% sensitivity, the response time of 106 seconds and a recovery time of 174 seconds to the sensor. The higher sensitivities with slow response and recovery times exhibit the behavior of redox reactions of sensor surface to the higher concentration of natural gas. The minute reduction in resistance and with the fast response and recovery time of the sensor show the 11.3% sensitivity to lower concentration. The more concentration of natural gas in the air would show a higher sensitivity of the sensor. The experimental results indicate the growth of ZnO nanorods on substrates and their sensitivity to natural gas.  Â

FORMATION DAMAGE MECHANISMS AND NUMERICAL SIMULATION OF PERMEABILITY IMPAIRMENT IN HORIZONTAL WELLS

Puzzling circumstance associated with formation damage near wellbore occur frequently, resulting in permeability impairments and increased pressure losses. Potential damage phenomenon usually starts from drilling to completion via production and such mechanisms have been fully considered. Most of the existing tasks to mitigate the near oil wellbore damages involve use of empirical models, conducting experiments, frequent shut down of wells for proper well tests and pressure maintenance are highly expensive and time consuming. Permeability impairments have been simulated by modifying Darcy’s equation to optimize reservoir pressure for improved near wellbore in horizontal wells. The model, transient linear partial differential equation (TLPDE) for impaired permeability is developed and numerically resolved using finite difference method. The model was implemented by writing codes in MATLAB language and the solution obtained was validated using synthetic/ field data. The results obtained for TLPDE model indicated pressure depletion over time. This was also shown for every values of coefficient of anisotropy until 400 days when the anisotropy became insignificant approaching isotropy condition, suggesting permeability impairment. Numerical simulation proved to be effective in simulating near oil wellbore damages. This paper describes the detailed mechanisms of formation damage and provided a numerical approach to model impaired permeability in horizontal wells. This approach allowed us to study the impact of various damage mechanisms related to drilling, completion conditions and significant improvement of near oil wellbore for well performance.

Thermodynamic Study on the Biosorptive Removal of Lead (II) Ions from Aqueous Solutions using Acid-treated Cystoseira tricta Biomass

Thermodynamic studies on adsorption process play a vital role in the estimation of adsorptive mechanisms (both physical and chemical). Estimating the accuracy of thermodynamic parameters is dependent upon the equilibrium constants between two phases (KL: dimensionless). In this study, thermodynamic parameters were calculated from the KL constant derived from the adsorption of Langmuir isotherms of Pb(II) on an sulphuric acid-treated brown algae Cystoseira stricta biomass at different temperatures. The conversion of the KL values to the dimensionless Kc values based on the Langmuir model was then assessed for thermodynamic parameters via the Van’t Hoff’s equation. The Pb(II) adsorption process onto the Cystoseira stricta biomass was spontaneous and feasible with DG values at 25, 30, 35 and 40 oC of -24.56 (95% C.I., -24.00 to -25.03), -22.60 (95% C.I.,-21.95 to -23.12), -20.90 (95% C.I.,-18.87 to -22.01) and -17.17 (95% C.I.,-17.71 to -21.41), respectively, and occurred in an endothermic nature (DH= -0.30 kJ/mol (95% C.I., -194.34 to 193.74) with an increased in randomness (DS= -299.47 J/mol×K (95% C.I., -553.60 to -45.35) kJ/mol). To confirm the accuracy and precision of the asymptotatic 95% confidence interval, Monte Carlo simulation may be carried out in the future.

A Simple Simulation of Surface Plasmon Resonance in The Kretschmann Configuration Using Google Sheets

This article describes a simple numerical simulation of three-layer surface plasmon resonance (SPR) in the Kretschmann configuration. The calculation was performed in Google Sheets, a web-based spreadsheet environment that functions similarly to Microsoft Excel where it is easily accessible for students via the internet. Specifically, Fresnel’s equations were utilized to calculate the intensity of the reflected light for the p-polarized incident light on a three-layer system. The complex functions were utilized to plot the SPR curves. We examined the change of the resonance angle by the influence of the incident wavelength. The simulation was also performed for different thicknesses of the gold film layer. To demonstrate the sensitivity, we obtained the SPR curves with the variation of the refractive index in the sensitive medium. The SPR accuracy was analysed by comparing our obtained result with the published work. It is intended to incorporate into undergraduate instrumental analysis courses.

On Analytical Solution of Time-Fractional Type Model of the Fisher’s Equation

In this paper, the time-fractional Fisher’s equation (TFFE) is considered to exam the analytical solution using the Laplace q-Homotopy analysis method (Lq-HAM)”. The Lq-HAM is a combined form of q-homotopy analysis method (q-HAM) and Laplace transform. The aim of utilizing the Laplace transform is to outdo the shortage that is mainly caused by unfulfilled conditions in the other analytical methods. The results show that the analytical solution converges very rapidly to the exact solution.

QUANTUM FIELD THEORY FROM FIRST PRINCIPLES

The mathematical description of quantum systems univocally identies their nature. In other words we treat a system as quantum if we describe its behaviour adopting Hilbert spaces and structures thereof, as prescribed by the postulates of quantum theory. The choice of using quantum systems as the elementary systems of physics can be justied in terms of informational principles, thanks to results of the last decade. Such results come as the conclusion of a research program that lasted almost one century, with the aim of reformulating quantum theory in terms of operational principles. This achievement now poses a new challenge, that we face here. If the systems of quantum theory are thought of as elementary information carriers in the rst place, rather than elementary constituents of matter, and their connections are logical connections within a given algorithm, rather than space-time relations, then we need to nd the origin of mechanical concepts—that characterise quantum mechanics as a theory of physical systems. To this end,we will illustrate howphysical laws can be viewed as algorithms for the update of memory registers that make a physical system. Imposing the characteristic properties of physical laws to such an algorithm, i.e. homogeneity, reversibility and isotropy, we will show that the physical laws thus selected are particular algorithms known as cellular automata. Further assumptions regarding maximal simplicity of the algorithm lead to two cellular automata only, that in a suitable regime can be described by Weyl’s dierential equations, lying at the basis of the dynamics of relativistic quantum elds. We will nally discuss how the same cellular automaton can give rise to both Fermionic eld dynamics and to Maxwell’s equations, that rule the dynamics of the electromagnetic eld. We will conclude reviewing the discussion of the relativity principle, that must be suitably adapted to the scenario where space-time is not an elementary notion, through the denition of a change of inertial reference frame, and whose formulation leads to the recovery of the symmetry of Minkowski space-time, identied with Poincar´e’s group. Space-time thus emerges as one of the manifestations of physical laws, rather than the background where they occur, and its features are determined by the dynamics of systems, necessarily equipped with dierential equations that express it. In brief, there is no space-time unless an evolution rule requires it.

OPTICAL MODELING OF FLUORINE DOPED TIN OXIDE FILMS FOR SPECTRALLY SELECTIVE APPLICATIONS

SnO2: F films are widely used for solar cell applications as the front electrode as well as other applications such as electrochromic and displays. The optical design of these and other applications need knowledge of optical constants. In this study we used the dielectric constant of a combined Drude and Lorentz to model the optical behaviour of SnO2: F. To do this, we used the fitting parameters from existing literature. From the model we got n and k values which we inserted into Fresnel R and T calculator and computed R and T spectra over the 300nm -2500nm wavelength range using Fresnel’s equations. We plotted n, k, T and R for different values of plasma frequency, and damping parameter, . The films exhibited very high visual transmittance and high infrared reflectance. The results implied the possibleness of the films to be employed as spectrally selective coating materials.

MOTION OF SOLID SPHERES UNDER SOLITARY WAVE ATTACK: PHYSICAL AND NUMERICAL MODELING

In this study, physical and numerical test are carried out focusing on the motion of two solid spheres under solitary wave attack. The numerical model CADMAS-SURF/3D-2F-DEM coupling a multiphase flow solver solving Reynolds Averaged Navier-Stokes Equations based on a porous body model and a discrete element method solver for Newton’s equations of motion is validated against the data of physical model experiments carried out in the wave flume of METU Ocean Engineering Research Center. Comparisons of the numerical simulations and physical model experiments show that the numerical model is capable of simulating the motion of solid spheres under solitary wave attack in a reasonably well accuracy.

Physicho and electrochemical characterization of PVC incorporated ZP composite membrane and their important parameters through applying TMS equation

The synthetic organic-inorganic composite membranes have enormous applications in the field of filtration and purification processes. The newly synthesized PVC (polyvinyl chloride) incorporated ZP (zinc phosphate) composite membrane is used as a barrier for the transportation of some strong electrolyte solutions like KCl, NaCl and LiCl. The composite material which used to make the membrane was qualitatively synthesized by sol-gel method of material synthesis. To characterize the structural and thermal properties of membrane there are different techniques like FTIR, XRD, TGA/DTA, SEM-EDX, LCR have been used. By characterizations it is clear that the material has crystalline nature, thermally stable and no breakages or cracks are found on membrane the surface. The electrochemical observation was done by potentiometer, which shows that the membrane is cation selective. To determine the charge density of membrane Teorell-Meyer-Sievers method is used. The observed potential and charge density of the incubated membrane follows KCl<NaCl<LiCl and KCl>NaCl>LiCl order respectively. The other important parameters like transport number, mobility ratio, charge effectiveness are also calculated by observed potential values.

TIME DEPENDENT INFLUENCE ON THE LATERAL RESPONSE OF SINGLE PILE SUBJECTED TO LATERAL LOAD

The time dependent response of the pile foundation can be categorized as one of the effective parameters that should be taken into account during analysis and design stage. From the literatures, very few reports are available on lateral response of the pile especially on the effect of soil type. It seems to be no exact solution for laterally loaded pile foundations in consolidating elasto-plastic soil to determine the design parameter such as maximum lateral pile displacement, ultimate lateral soil resistance and p-y relationship. Therefore, this study investigates the effect of soil type with different intensities of loading on the lateral pile deformation and lateral soil pressure with time. Finite element analysis is carried out to evaluate the lateral pile response embedded in cohesionless and cohesive soil subjected to pure lateral load. The simulation include linear elastic model to represent the pile structural material and Mohr-Coulomb elasto-plastic model to represent the surrounding soil. Biot’s equation of consolidation is used to govern the elasto-plastic material. The complete model of the whole geotechnical system are used to assess the lateral pile displacement and lateral soil pressure developed at pile face of 15m pile length and 1m pile diameter. It is shown that the lateral pile displacements increased and the lateral soil pressure was redistributed with time due to consolidation process.

The Role of Distance in the Gravity Model: From the View of Newton, International Economics and Quantum Mechanics

The gravity model widely used in international economics in order to explain bilateral trade flows between countries has its roots in physics and the common variable suggested in both of the equations used in physics and economics is “distance”. Although several variables expected to have significant effect on trade are added to the analysis in the field of international economics lately; distance is always considered as the first issue because of its correlation with transportation costs. Similarly, from it was first suggested by Newton in the equation of the universal gravity law to Einstein and to the recent finding in the field of quantum mechanics much attention has been paid to distance in physics research too. The aim of this paper is to examine the role of distance in the gravity models considering economic and physics perspectives with an eye to Newton’s equation, Einstein’s relativity and quantum mechanics.

Synthesis, characterization and electrochemical observation of PVC based ZMP composite porous membrane and its physicochemical studies by applying some strong electrolytes through TMS equation

PVC based zinc molybdophosphate (ZMP) has been synthesized via sol gel method of material synthesis, which is used to design a mechanically stable organic-inorganic composite membrane. The composite material plus membrane has been characterized by using various sophisticated techniques like x-ray diffraction, fourier transforms infrared spectroscopy, scanning electron microscopy, thermo gravimetric/differential thermal analysis and simultaneously potentiometer analysis also. The characterizations confirmed that there is a strong interaction found between PVC and ZMP particles and the resulting composite has indicated higher thermal stability than the pure material. It also demonstrated the material nature, functional groups, surface structure, thermal stability, porosity, and ion transportation etc. Teorell, Meyer, and Sievers (TMS) theoretical approach is used to explain the various electrochemical applications of membrane like charge density, transport number, mobility ratio, charge effectiveness etc. Some strong electrolytes like KCl, NaCl and LiCl are used to explain the membrane behavior which has been confirmed by observing the ionic potential and charge density of membrane.

Simulation and Validation of Airflow Pressure Patterns in Hopper-Bottom Bins Filled with Wheat

<abstract> <b><sc>Abstract. </sc></b>A non-linear model that can explain the three-dimensional airflow pressure patterns in grains was developed and solved using the finite element method. The model can simulate airflow distribution in both flat-bottom and hopper-bottom bins of different shapes such as square, rectangular, or cylindrical. Resistance to airflow through the grain bed was explained using a modified form of Darcy’s equation. The airflow model was validated against experimental data obtained from studies conducted in a 4.72 m diameter hopper-bottom bin filled with wheat, aerated using a 1.82 m vertical rocket-type aerator. The relative error between the experimental and predicted static pressure values for the entire bin geometry was less than 3.2%, with higher values at regions near the aerator. The validated model can be used to predict the static pressure patterns and airflow distribution (because airflow lines are perpendicular to iso-pressure lines) in various grain beds and can handle variations in product type, moisture content, grain surface configurations, foreign material content, direction of airflow, and aeration duct designs. Using the validated model, airflow pressure patterns in a hopper-bottom cylindrical bin with 10 different duct configurations were predicted and results were discussed for their implications for aeration and near-ambient air drying. The airflow pressure patterns as affected by variations in airflow rate, grain surface configuration (peaked, levelled and conically cored), bin geometry, direction of airflow, and grain bed height (grain filled up to 40%, 60%, and 80% of the bin height) were also simulated and discussed.

On the Zitterbewegung Transient Regime in a Coarse-Grained Space-Time

In the present contribution, by studying a fractional version of Dirac’s equation for the electron, we show that the phenomenon of Zitterbewegung in a coarse-grained medium exhibits a transient oscillatory behavior, rather than a purely oscillatory regime, as it occurs in the integer case, . Our result suggests that, in such systems, the Zitterbewegung-type term related to a trembling motion of a quasiparticle is tamed by its complex interactions with other particles and the medium. This can justify the difficulties in the observation of this interesting phenomenon. The possibility that the Zitterbewegung be accompanied by a damping factor supports the viewpoint of particle substructures in Quantum Mechanics.

Cosmological Entropy and Seeking of Genesis of Time

Influenced with symmetry of entropy and time in nature, we tried to invoke relation between entropy and time in space-time with new dimension. And also provided how Hubble’s constant related with entropy of universe. Discussed about how entropy of universe behaves at different temperatures and at different time values of universe. We showed that age of universe is equivalent to Hubble’s constant. And showed how naturally entropy arrives from the manipulations in gravity from Einstein’s equation “00”. And from these results we concluded that universe is isotropic, homogeneous with negative space curvature i.e. K= -1 but not flat K=0 (which doesn’t explain acceleration and deceleration of universe). From these results of gravity, entropy, temperature and time we discussed the genesis of time. And proposed that at absolute zero temperature universe survives as a superconductor and that particular temperature is called as “Critical Absolute Temperature (TAB). And genesis of time occurs at first fluxon repulsion in the absolute zero temperature of universe.Â

Relativistic analysis of application of Helmholtz theorem to classical electrodynamics

In this work we discuss the relationship between the instantaneous-action-at-a-distance solutions of Maxwell’s equations obtained using Helmholtz theorem and the Lorentz’s invariant solutions of the same equations obtained using Special Relativity postulates. We show that Special Relativity postulates are not consistent with Helmholtz’s theorem in the presence of charges and currents, but in the vacuum, without charges and currents, Helmholtz’s theorem and Special Relativity agree because the instantaneous-action-at-a-distance solutions can be eliminated using a gauge transformation.

VISUAL DESIGN TOOL FOR ELECTROSTATIC LELSES

Current research presents a visual-computational tool to design and investigate round electrostatic lenses in sense of analysis procedure. The finite elements methods is adopted to find the electrostatic potential in the lens region. Laplace’s equation is first replaced by a certain functional which physically represent the electric energy stored in the electric field. This functional is then minimized at each mesh point with respect to the nearest eight ones. This minimization process is proved to be entirely equivalent to solving Laplace’s equation. The requirement that the functional being minimized is then yields a set of nine point equations which inter relate the potentials at adjacent mesh points. Finally this set of equations is solved to find the electrostatic potential at each mesh point in the region of the lens under consideration. The procedure steps mention above are coded to program written in visual basic. Hence an interface tool for analyzing and designing electrostatic lenses has been built up. Designing results proved that the introduced tools has an excellent outputs in comparison with the others written in not visual programming languages. Furthermore it easier for researchers and designer to use such a tool over their counterpart ones.

Finite-Difference Time-Domain (FDTD) Simulation of Novel Terahertz Structures

Previous work on compact, variable, efficient, high brightness radiation sources is extended by calculating the radiated power and angular distributions for different configurations and drive sources. Figures of merit are defined in terms of efficiencies or effective impedances such as the radiation coupling impedance Zr .Characteristics of representative cases are discussed in terms of a few basic parameters. Conditions for interference are discussed and demonstrated. Finally, we discuss some further possibilities together with various impediments to realizing such devices. The differences between bound and free electrons are studied from the standpoint of the frequencies that are practicably achievable. With the ansatz that the transport physics with Maxwell’s Equations are valid but modified by the material properties, a number of analogs exist between these two basic sources of radiation. In many cases, the differences are between macro and micro implementations e.g. between klystrons and klystrinos (micro or nano)  or solid state and semiconductor lasers or rare-earth doped transistors. Cases with no apparent analogs are ones due to unique quantum effects e.g. radiation at 3kTc in superconductors. This is well above magnetic resonance imaging MRI around 0.4 eV but well below room temperature at 25 meV. Bound and free possibilities for planar, micro undulators over this range are studied using FDTD techniques. To our knowledge, there have been no implementations of either possibility.

A 2D hydrodynamic-sedimentological model for gravel-bed rivers. Part I: theory and validation

This paper presents a novel 2D-depth average model especially developed for gravel-bed rivers, named Lican-Leufú (Lican=pebble and Leufu=river, in Mapuche’s language, the native inhabitants of Central Patagonia, Argentina). The model consists of three components: a hydrodynamic, a sedimentological, and a morphological model. The flow of water is described by the depth-averaged Reynolds equations for unsteady, free-surface, shallow water flows. It includes the standard k-e model for turbulence closure. Sediment transport can be divided in different size classes (sand-gravel mixture) and the equilibrium approach is used for Exner’s equation. The amour layer is also included in the structure of the model and the surface grain size distribution is also allowed to evolve. The model simulates bank slides that enable channel widening. Models predictions were tested against a flume experiment where a static armour layer was developed under conditions of sediment starvations and general good agreements were found: the model predicted adequately the sediment transport, grain size of transported material, final armour grain size distribution and bed elevation.

A Simulation-Optimization Model for Air Sparging and Pump and Treat Groundwater Remediation Technologies

Using a new concept of sub-period, a simulation-optimization model for initial evaluation of air sparging (AS) and pump-and-treat (PAT) groundwater remediation technologies is presented in order to facilitate the study of aquifers contaminated with soluble volatile organic compounds. The new simulation and optimization process assumes a specific type of contaminant and a homogeneous soil texture. The simulation module connects two existing models (MODFLOW and MT3DMS) to Henry's Equation. Simulation is performed by dividing the simulation period into sub-periods and using Henry’s equation for each sub-period. An optimization module minimizes the cost of the remediation using an objective function subjected to quality and quantity constraints, and derived using a classic form of genetic algorithm. In addition to demonstrating how to solve a typical problem using the optimization module, we demonstrate field application of the simulation module for an aquifer near the Tehran Refinery, which is contaminated by methyl tertiary-butyl ether. One constraint for this problem is that installation of remediation equipment is prohibited in urban areas. Due to this constraint, AS wells must be positioned upward the urban area. Therefore, these wells act as a barrier that restricts contaminant flow downward into the city. The results of the simulation show the advantages of employing simultaneous remediation technologies.