Physics Research International The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. Liquid Mass Sensing Using Resonating Microplates under Harsh Drop and Spray Conditions Wed, 31 Dec 2014 09:40:57 +0000 We have performed in situ real time mass sensing of deposited liquid volatile droplets and sprays using plate-like microstructures, with robust and reusable performance attained over harsh conditions and multiple cycles of operation. A home-built electrooptical sensing system in ambient conditions has been used. The bimorph effect on the resonant frequency of altered mass loading, elasticity, and strain had been carefully compared, and the latter were found to be negligible in the presence of nonviscous liquids deposited on top of our microplate devices. In resonant mode, the loaded mass has been estimated from measured resonant frequency shifts and interpreted from a simple, uniformly deposited film model. A minimum submicrogram detectable mass was estimated, suggesting the system’s potential for robust, fast, and reusable sensing capabilities, in the presence of volatile liquids under harsh operation conditions. Said Mahajne, Dafne Guetta, Stella Lulinsky, Slava Krylov, and Yoav Linzon Copyright © 2014 Said Mahajne et al. All rights reserved. Modified Hamiltonian Formalism for Regge-Teitelboim Cosmology Sun, 28 Dec 2014 08:35:14 +0000 The Ostrogradski approach for the Hamiltonian formalism of higher derivative theory is not satisfactory because the Lagrangian cannot be viewed as a function on the tangent bundle to coordinate manifold. In this paper, we have used an alternative approach which leads directly to the Lagrangian which, being a function on the tangent manifold, gives correct equation of motion; no new coordinate variables need to be added. This approach can be used directly to the singular (in Ostrogradski sense) Lagrangian. We have used this method for the Regge-Teitelboim (RT) minisuperspace cosmological model. We have obtained the Hamiltonian of the dynamical equation of the scale factor of RT model. Pinaki Patra, Md. Raju, Gargi Manna, and Jyoti Prasad Saha Copyright © 2014 Pinaki Patra et al. All rights reserved. Exact Traveling Wave Solutions for Wick-Type Stochastic Schamel KdV Equation Mon, 15 Dec 2014 00:10:14 +0000 F-expansion method is proposed to seek exact solutions of nonlinear partial differential equations. By means of Hermite transform, inverse Hermite transform, and white noise analysis, the variable coefficients and Wick-type stochastic Schamel KdV equations are completely described. Abundant exact traveling wave solutions for variable coefficients Schamel KdV equations are given. These solutions include exact stochastic Jacobi elliptic functions, trigonometric functions, and hyperbolic functions solutions. Hossam A. Ghany and M. Zakarya Copyright © 2014 Hossam A. Ghany and M. Zakarya. All rights reserved. The Potentially Dangerous Asteroid (101955) Bennu Mon, 15 Dec 2014 00:10:10 +0000 We computed impact solutions of the potentially dangerous asteroid (101955) Bennu based on 569 optical observations from September 11.40624 UTC, 1999 to January 20.11189 UTC, 2013, and 29 radar observations from September 21, 1999, through September 29, 2011. Using the freely available OrbFit software package, we can follow its orbit forward in the future searching for close approaches with the earth, which can lead to possible impacts up to 2200. With the A2 nongravitational parameter in the motion of the asteroid (101955) Bennu we computed possible impact solutions using different JPL planetary and lunar ephemerides and different number of additional massive perturbed asteroids. The possible impact path of risk for 2175 is presented. Additionally, we computed possible impact solutions using the normal places method of the selection of Bennu’s astrometric observations. Moreover, we computed time evolution of the mean orbital elements and the orbital nodes of Bennu 5 kyr in the backwards and 1 kyr in the future using the Yarkovsky effects. We computed the mean motion and secular orbital resonances of the Bennu. We also computed the influence of the JPL planetary and lunar ephemerides DE403, DE405, DE406, DE414, and DE423 on the close approaches of the asteroid (101955) Bennu with the earth. I. Włodarczyk Copyright © 2014 I. Włodarczyk. All rights reserved. Analytical Approximations of Whispering Gallery Modes in Anisotropic Ellipsoidal Resonators Wed, 10 Dec 2014 00:10:32 +0000 Numerical evolutions of whispering gallery modes of both isotropic and anisotropic spheroidal resonators are presented and are used to build analytical approximations of these modes. Such approximations are carried out mainly to have the possibility to have manageable analytic formulas for the eigenmodes and eigenfrequencies of anisotropic resonators. A qualitative analysis of ellipsoidal anisotropic modes in terms of superposition of spherical modes is also presented. Marco Ornigotti and Andrea Aiello Copyright © 2014 Marco Ornigotti and Andrea Aiello. All rights reserved. Electronic Transport Properties of Doped C28 Fullerene Wed, 26 Nov 2014 12:56:23 +0000 Endohedral doping of small fullerenes like C28 affects their electronic structure and increases their stability. The transport properties of Li@C28 sandwiched between two gold surfaces have been calculated using first-principles density functional theory and nonequilibrium Green’s function formalism. The transmission curves, IV characteristics, and molecular projected self-consistent Hamiltonian eigenstates of both pristine and doped molecule are computed. The current across the junction is found to decrease upon Li encapsulation, which can be attributed to change in alignment of molecular energy levels with bias voltage. Akshu Pahuja and Sunita Srivastava Copyright © 2014 Akshu Pahuja and Sunita Srivastava. All rights reserved. Synthesis and Characterization of Screen Printed Zn0.97Cu0.03O Thick Film for Semiconductor Device Applications Mon, 24 Nov 2014 00:00:00 +0000 The studies on doped ZnO thick films deposited over large surface area are still a very promising area of research and development. We report characteristic properties of thick film of Zn0.97Cu0.03O prepared by the economic screen printing technique. The film was characterized by XRD, SEM, diffused reflectance, FTIR, and dark resistivity measurement techniques. The XRD and SEM studies revealed polycrystalline, single phase, porous, and granular surface morphology of this Cu doped ZnO thick films. The direct band gap energy of this film determined by diffuse reflectance technique is 3.18 eV. IR transmission spectrum measured in 4000–600 cm−1 region at ambient temperature confirmed the incorporation of Cu2+ ions in ZnO lattice. The DC resistivity measurements reveal semiconducting nature of the sample with activation energy of 0.66 eV. Rayees Ahmad Zargar, Sharief Ud Din Khan, Mohd Shahid Khan, Manju Arora, and Aurangzeb Khurram Hafiz Copyright © 2014 Rayees Ahmad Zargar et al. All rights reserved. Advancement in Microstructural, Optical, and Mechanical Properties of PVA (Mowiol 10-98) Doped by ZnO Nanoparticles Thu, 20 Nov 2014 00:00:00 +0000 The current paper explores the preparation of PVA nanocomposites by doping with zinc oxide (ZnO) nanoparticles using the method of coagulation and solvent casting technique. The dopant zinc oxide nanoparticle is prepared by simple precipitation method and is confirmed by the X-ray diffraction (XRD) studies. The XRD studies explore that the average particle size of the synthesized nanoparticles is 55 nm and show that the crystallinity factor of PVA nanocomposites is influenced by the interaction occurring between the PVA main chain and the ZnO nanoparticle. The FTIR spectroscopy suggests that the formulation of complexes occurring between the dopants and the PVA main chain is due to inter or intra molecular hydrogen bonding. UV-vis spectra explore the dramatic decrease in the optical energy gap of nanoparticles doped polymer composites and the variations of Urbach energy () related to crystallinity for various dopant concentrations. The mechanical properties of the PVA nanocomposites were explored using universal testing machine (UTM) that reflects that, for % doping concentration, there is an increase in the tensile strength, stiffness, and Young’s modulus, whereas, for % concentration, the percentage total elongation at fracture is found to be the maximum. The morphological behavior and homogenous nanoparticle distribution in the composites were examined by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDAX). N. B. Rithin Kumar, Vincent Crasta, and B. M. Praveen Copyright © 2014 N. B. Rithin Kumar et al. All rights reserved. Retracted: Influence of Magnesium Substitution on Thermal and Electrical Properties of NiCuZn Ferrites for Microinductor Core Applications Thu, 30 Oct 2014 08:30:58 +0000 Physics Research International Copyright © 2014 Physics Research International. All rights reserved. Resolution of the Age-Old Dilemma about a Magnitude of the Momentum of Light in Matter Tue, 28 Oct 2014 06:29:28 +0000 There are two competitive opinions about a magnitude of the momentum of light in matter. The Balazs thought experiment gives unambiguous theoretical evidence based only on laws of mechanics that the momentum of light in matter is smaller by n times than that of the same light in free space where n is the refractive index of the matter. On the other hand, there is other theoretical evidence confirmed by experimental investigation that the momentum of light in matter is greater by n times than that in free space. This ancient dilemma cannot be resolved till now. We show that the momentum density flux of light in matter is greater by n times than that in free space. In the same time we present an alternative interpretation of the Balazs thought experiment where two optical pressures arising in the regions of the matter where leading and trailing edges of the pulse are propagating are taken into account. This enables us to match contradictory results of mentioned experiments. Since the contradiction is overcome, the dilemma disappears. V. P. Torchigin and A. V. Torchigin Copyright © 2014 V. P. Torchigin and A. V. Torchigin. All rights reserved. Structural and Electrical Properties of Li–Ni Nanoferrites Synthesised by Citrate Gel Autocombustion Method Mon, 20 Oct 2014 09:12:50 +0000 An attempt has been made to synthesize nanocrystalline lithium-nickel ferrites with a compositional formula Li0.5−0.5xNixFe2.5−0.5xO4 (where to 1.0 with step of 0.2) by a low temperature citrate gel autocombustion method. Single phase cubic structure is confirmed by X-ray diffraction analysis. This result demonstrates that the prepared samples are homogeneous and the sharp peaks reveal that the samples are in good crystalline form. As the Ni concentration is increased, various interesting changes in the values of the structural parameters like lattice parameter, X-ray density, bulk density, and porosity have been observed. The surface morphology of the prepared samples was studied using scanning electron microscopy (SEM). The DC resistivity measurements were carried out using two-probe method from 200°C to 600°C. The variation of with reciprocal of temperature shows a discontinuity at Curie temperature. versus plot of the pure lithium ferrites is almost linear which indicates the Curie temperature of the pure lithium ferrites was beyond our measured temperature. The dielectric properties of these ferrites have been studied using a LCR meter from the room temperature to 700 K at various frequencies up to 5 MHz, which reveals that all the prepared samples have dielectric transition temperature around 600 K. G. Aravind, D. Ravinder, and V. Nathanial Copyright © 2014 G. Aravind et al. All rights reserved. Multigap Superconductivity in the Ferromagnetic Superconductor UCoGe Revealed by Thermal Conductivity Measurements Thu, 09 Oct 2014 08:02:03 +0000 We performed thermal conductivity measurements on a single crystal of the ferromagnetic superconductor UCoGe under magnetic field. Two different temperature dependencies of the thermal conductivity are observed, for : linear at low magnetic field and quadratic for magnetic field larger than 1 Tesla. At the same field value, a plateau appears in the field dependency of the residual term of thermal conductivity. Such observations suggest a multigap superconductivity with a line of nodes in the superconducting gap. Ludovic Howald, Mathieu Taupin, and Dai Aoki Copyright © 2014 Ludovic Howald et al. All rights reserved. Reconstruction of Dielectric Constants of Core and Cladding of Optical Fibers Using Propagation Constants Measurements Thu, 18 Sep 2014 12:51:08 +0000 We present new numerical methods for the solution of inverse spectral problem to determine the dielectric constants of core and cladding in optical fibers. These methods use measurements of propagation constants. Our algorithms are based on approximate solution of a nonlinear nonselfadjoint eigenvalue problem for a system of weakly singular integral equations. We study three inverse problems and prove that they are well posed. Our numerical results indicate good accuracy of new algorithms. E. M. Karchevskii, A. O. Spiridonov, A. I. Repina, and L. Beilina Copyright © 2014 E. M. Karchevskii et al. All rights reserved. Full Symmetry Groups and Exact Solutions to BKP and GKP Equations Thu, 18 Sep 2014 05:34:57 +0000 We investigate the (2+1)-dimensional nonlinear BKP and GKP equations with the modified direct CK’s method. Then, we get its Lie point groups and the full symmetry group, and a relationship is constructed between the new solutions and the old one. Based on the relationship, the new solutions can be obtained by using a given solution of the equations. Bo Ren and Jian-Yong Wang Copyright © 2014 Bo Ren and Jian-Yong Wang. All rights reserved. Retracted: Structural and Optical Properties of Germanium Thin Films Prepared by the Vacuum Evaporation Technique Tue, 16 Sep 2014 00:00:00 +0000 Physics Research International Copyright © 2014 Physics Research International. All rights reserved. Drift Modified Longitudinal Electrokinetic Mode in Colloids Laden Semiconductor Quantum Plasmas Mon, 15 Sep 2014 09:10:17 +0000 Dispersion and absorption characteristics of electrokinetic wave in unmagnetised extrinsic semiconductor with streaming carriers are analytically investigated. By using quantum hydrodynamic model, a linear dispersion relation is derived for longitudinal electrokinetic wave in colloids laden semiconductor plasma under slow electrokinetic mode regime. Results indicate that quantum effect through Bohm potential significantly modifies the dispersion and absorption characteristics of electrokinetic wave spectrum. The outcome is hoped to add substantially to the present knowledge of wave spectrum of longitudinal electrokinetic wave in colloids laden quantum semiconductor plasma subjected to a dc electric field along the direction of wave propagation. Sandhya Chaudhary, Nilesh Nimje, Nishchhal Yadav, and S. Ghosh Copyright © 2014 Sandhya Chaudhary et al. All rights reserved. Cusp Catastrophe Model for Description of Bistability in Ferroelectric Liquid Crystals Mon, 01 Sep 2014 00:00:00 +0000 We propose a new theoretical approach for description of the equilibrium and bistable states of ferroelectric liquid crystal. A sample of ferroelectric liquid crystal is considered in the “bookshelf” geometry under the influence of electric field. Continuum and perturbation theories are used in order to establish the relation between the scale coefficients in the expansion for the azimuthal angle. The equilibrium states of ferroelectric SmC* are determined in the framework of the catastrophe theory. Nail Migranov, Aleksey Kudreyko, and Denis Kondratyev Copyright © 2014 Nail Migranov et al. All rights reserved. Monte Carlo Simulations of a Scanning System Based on a Panoramic X-Ray Tube with a Conical Anode Thu, 21 Aug 2014 07:11:42 +0000 Monte Carlo simulations were used to study photon production in a panoramic X-ray tube with a conical tungsten target to determine the optimal characteristics of the target shape and electron beam configuration. Several simulations were performed for accelerating potentials equal to 250 kV, 300 kV, and 500 kV with electron beams of various radii and anode sizes. The angular distribution of the photon intensity was analysed by numerical calculations for an assembly composed of an X-ray tube and an external collimator with a cylindrical hole to simulate a panoramic scanning system with an X-ray pencil beam. Andrii Sofiienko, Chad Jarvis, and Ådne Voll Copyright © 2014 Andrii Sofiienko et al. All rights reserved. Can SGRs/AXPs Originate from Neutron Star Binaries? Thu, 21 Aug 2014 06:04:07 +0000 Soft gamma repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are two groups of enigmatic objects, which have been extensively investigated in past few decades. Based on the ample information about their timing behaviors, spectra, and variability properties, it was proposed that SGRs/AXPs are isolated neutron stars (NSs) with extremely strong magnetic fields, the so-called magnetars. Nonetheless, some alternative models are probably equally convincing such as those proposing that they are accreting NSs with a fall-back disk or rotation-powered magnetized and massive white dwarfs. The nature and nurture of SGRs/AXPs remain controversial. In this paper, we propose that SGRs/AXPs can, alternatively, originate from normal NSs in binary systems, which resorts to the reexplosion of normal NS induced by instant contraction of the massive star envelope in a Thorne-Żytkow object (TZO). The spin-period clustering is due to either the brake of a slowly rotating envelope or the frictional drag during the common-envelope phase. Joan Jing Wang and Hsiang-Kuang Chang Copyright © 2014 Joan Jing Wang and Hsiang-Kuang Chang. All rights reserved. How Much Asymmetry of Colliding Pair Affects Nuclear Dynamics at Balance Point? Wed, 20 Aug 2014 07:28:13 +0000 Using the quantum molecular dynamics model, we study the nuclear dynamics at the balance energy of mass asymmetric colliding nuclei by keeping the total mass of the system fixed and by varying the mass asymmetry (, where and are the masses of the target and projectile, resp.) of the reaction. In particular, we study the various quantities like average and maximum density and temperature, collision rate, participant-spectator matter, anisotropic ratio, relative momentum, and their mass asymmetry and mass dependence. Our results indicate sizeable effect of mass asymmetry on these quantities. Supriya Goyal Copyright © 2014 Supriya Goyal. All rights reserved. Multiparty Quantum Communication Using Multiqubit Entanglement and Teleportation Mon, 11 Aug 2014 11:34:53 +0000 We propose a qubit entangled channel that can be used to teleport qubits in a network to a single receiver. We describe the structure of this channel and explicitly demonstrate how the protocol works. The channel can be used to implement a scheme in which all parties have to participate in order for the teleportation to be successful. This can be advantageous in various scenarios and we discuss the potential application of this protocol to voting. S. Ghose, A. Kumar, and A. M. Hamel Copyright © 2014 S. Ghose et al. All rights reserved. Measurement in the de Broglie-Bohm Interpretation: Double-Slit, Stern-Gerlach, and EPR-B Sun, 10 Aug 2014 08:55:34 +0000 We propose a pedagogical presentation of measurement in the de Broglie-Bohm interpretation. In this heterodox interpretation, the position of a quantum particle exists and is piloted by the phase of the wave function. We show how this position explains determinism and realism in the three most important experiments of quantum measurement: double-slit, Stern-Gerlach, and EPR-B. First, we demonstrate the conditions in which the de Broglie-Bohm interpretation can be assumed to be valid through continuity with classical mechanics. Second, we present a numerical simulation of the double-slit experiment performed by Jönsson in 1961 with electrons. It demonstrates the continuity between classical mechanics and quantum mechanics. Third, we present an analytic expression of the wave function in the Stern-Gerlach experiment. This explicit solution requires the calculation of a Pauli spinor with a spatial extension. This solution enables us to demonstrate the decoherence of the wave function and the three postulates of quantum measurement. Finally, we study the Bohm version of the Einstein-Podolsky-Rosen experiment. Its theoretical resolution in space and time shows that a causal interpretation exists where each atom has a position and a spin. Michel Gondran and Alexandre Gondran Copyright © 2014 Michel Gondran and Alexandre Gondran. All rights reserved. Work Criteria Function of Irreversible Heat Engines Tue, 05 Aug 2014 11:57:19 +0000 The irreversible heat engine is reconsidered with a general heat transfer law. Three criteria known in the literature—power, power density, and efficient power—are redefined in terms of the work criteria function (WCF), a concept introduced in this study. The formulation enabled the suggestion and analysis of a unique criterion—the efficient power density (which accounts for the efficiency and power density). Practically speaking, the efficient power and the efficient power density could be defined on any order based on the WCF. The applicability of the WCF is illustrated for the Newtonian heat transfer law (n=1) and for the radiative law (n=4). The importance of WCF is twofold: it gives an explicit design and educational tool to analyze and to display graphically the different criteria side by side and thus helps in design process. Finally, the criteria were compared and some conclusions were drawn. Mahmoud Huleihil Copyright © 2014 Mahmoud Huleihil. All rights reserved. Various Constructions of Qudit SWAP Gate Tue, 05 Aug 2014 07:51:25 +0000 It is known that SWAP operation for quantum systems of arbitrary dimension can be implemented using various qudit gates. In this paper, equivalence of some important qudit operations is demonstrated. Equivalence of the qudit operations is exploited to minimize the circuit complexity in the previously proposed qudit SWAP gate constructions. Further, constructions of qudit SWAP operation with minimum number of qudit gates are also proposed. Importantly, these circuit constructions of SWAP retain its properties like symmetry and simplicity. S. Balakrishnan Copyright © 2014 S. Balakrishnan. All rights reserved. Structural and Optical Investigations of Heterostructures Based on :Si Solid Solutions Obtained by MOCVD Wed, 23 Jul 2014 06:40:34 +0000 We investigated MOCVD epitaxial heterostructures based on AlxGa1−xAs ternary solid solutions, obtained in the range of compositions and doped with high concentrations of phosphorus and silicon atoms. Using the methods of high-resolution X-ray diffraction, scanning electron microscopy, X-ray microanalysis, Raman spectroscopy, and photoluminescence spectroscopy we have shown that grown epitaxial films represent five-component (AlxGa1−xAs1−yPy)1−zSiz solid solutions. The implementation of silicon in solid solution with a concentration of ~ 0.01 at.% leads to the formation of the structure with deep levels, DX centers, the occurrence of which fundamentally affects the energy characteristics of received materials. P. V. Seredin Copyright © 2014 P. V. Seredin. All rights reserved. Synthesis, Structural and Optical Investigations of (Pb, Bi)TiO3 Borosilicate Glasses Sun, 13 Jul 2014 09:55:22 +0000 A new series of lead bismuth titanate borosilicate glasses with addition of one percent lanthanum oxide have been synthesized using melt-quench technique. X-ray diffraction patterns have been recorded to confirm the amorphous nature of the prepared glass samples. The synthesized glasses have been characterized by using various spectroscopic techniques such as UV-visible, infrared, and Raman spectroscopy. UV-visible measurements were recorded in the wavelength range from 200 to 1100 nm whereas IR and Raman spectroscopic measurements were recorded over a continuous wavenumber range from 400 to 5000 cm−1 and 1000 to 2000 cm−1 respectively. The different absorption peaks/bands were formed in IR spectral patterns. The spectral bands appear towards the lower wavenumber sides due to the Bi and Pb, content while the bands appear towards the higher wavenumber sides due to the formation of diborate and triborate network units. Chandkiram Gautam Copyright © 2014 Chandkiram Gautam. All rights reserved. Renormalization of QED Near Decoupling Temperature Tue, 24 Jun 2014 09:01:06 +0000 We study the effective parameters of QED near decoupling temperatures and show that the QED perturbative series is convergent, at temperatures below the decoupling temperature. The renormalization constant of QED acquires different values if a system cools down from a hotter system to the electron mass temperature or heats up from a cooler system to the same temperature. At , the first order contribution to the electron self-mass, is 0.0076 for a heating system and 0.0115 for a cooling system and the difference between two values is equal to 1/3 of the low temperature value and 1/2 of the high temperature value around . This difference is a measure of hot fermion background at high temperatures. With the increase in release of more fermions at hotter temperatures, the fermion background contribution dominates and weak interactions have to be incorporated to understand the background effects. Samina S. Masood Copyright © 2014 Samina S. Masood. All rights reserved. Vector Potential Quantization and the Quantum Vacuum Thu, 19 Jun 2014 10:46:32 +0000 We investigate the quantization of the vector potential amplitude of the electromagnetic field to a single photon state starting from the fundamental link equations between the classical electromagnetic theory and the quantum mechanical expressions. The resulting wave-particle formalism ensures a coherent transition between the classical electromagnetic wave theory and the quantum representation. A quantization constant of the photon vector potential is defined. A new quantum vacuum description results directly in having very low energy density. The calculated spontaneous emission rate and Lambs shift for the states of the hydrogen atom are in agreement with quantum electrodynamics. This low energy quantum vacuum state might be compatible with recent astrophysical observations. Constantin Meis Copyright © 2014 Constantin Meis. All rights reserved. Coherent and Incoherent Scattering Cross Sections of Some Lead and Sodium Compounds at Angles below 10° for 241Am Gamma Rays Mon, 02 Jun 2014 06:50:07 +0000 We report the total (coherent + incoherent) scattering cross sections of some lead and sodium compounds measured at angles less than 10° for 241Am (59.54 keV) gamma rays. The experimental cross sections so obtained are compared with the data interpolated from theoretical compilations based on nonrelativistic Hartree-Fock (NRHF) model for the samples of interest. In the low momentum transfer region studied, it is observed that the nonrelativistic theoretical total scattering cross sections computed using HF form factor and scattering function tabulated by NRHF are quite adequate in explaining the measured total scattering cross sections. L. Vinaykumar and T. K. Umesh Copyright © 2014 L. Vinaykumar and T. K. Umesh. All rights reserved. Free Convective Fluctuating MHD Flow through Porous Media Past a Vertical Porous Plate with Variable Temperature and Heat Source Tue, 06 May 2014 07:54:23 +0000 Free convective magnetohydrodynamics (MHD) flow of a viscous incompressible and electrically conducting fluid past a hot vertical porous plate embedded in a porous medium in the presence of heat source has been studied in this paper. The temperature of the plate varies both in space and time. The main objective of this paper is to study the effect of porosity of the medium coupled with the variation of plate temperature with regard to space and in time. The effect of pertinent parameters characterizing the flow has been presented through the graphs. It is important to record that the presence of porous media has no significant contribution to the flow characteristics and viscous dissipation compensates for the heating and cooling of the plate due to convective current. A. K. Acharya, G. C. Dash, and S. R. Mishra Copyright © 2014 A. K. Acharya et al. All rights reserved.