Layered petroleum reservoirs with cross-flows

Studied is a cylindrical reservoir consisting of three layers: a water-containing bottom layer, and two oil-containing top layers from whose upper layer oil is produced. For its solution, a corrected version of the finite Hankel transform for Neumann-Neumann boundary conditions was used together with numerical inversion of the Laplace transform. The effects of the water zone on the unsteady state pressure in the reservoir were evaluated at distances away from the well and at the well-bore itself. We found that the vertical pressure drop increases gradually with time and is more significant in the vicinity of the well-bore. For constant production and at any time t, smaller reservoirs experience higher pressure drops than larger ones. For the reservoir investigated, we found that for nondimensional time t _Dw <10⁴ the presence of a second fluid (water) has no effect on the pressure drop. Of all the formation and fluid properties investigated, porosity has the largest effect on pressure.Nomenclature c ₁, c ₂ Oil and water compressibilities, vol/vol/atm, vol/vol/psi - h Height of water zone from bottom of reservoir, cm, ft - h _D h/r _w , non-dimensional - H Height of reservoir, cm, ft - H _D H/r _w, non-dimensional - J ₀, J ₁ Bessel functions of the first kind, zero and first-order - K _r2, K _r1 Oil and water zones, horizontal permeabilities, darcies, md - K _z2, K _z1 Oil and water zones, vertical permeabilities, darcies, md - k ₁ n=1, 2, 3... - k ₂ n=1, 2, 3... - k _1,0 - k _2,0 - p(r, z, t) P(r, z, 0)–P(r, z, t), atm, psi - P(r, z, t) Pressure at any layer in the reservoir, atm, psi - P(r, z, 0) Initial pressure at any layer in the reservoir, atm, psi - P _D , non-dimensional - q Constant production rate of well, cc/sec, barrels/day - r Radius of reservoir, cm, ft - r _D r/r _w , non-dimensional - r _e Drainage radius, cm, ft - r _eD re/r _w , non-dimensional - r _w Well-bore radius, cm, ft - t Time, sec, hr - _Dw (k _r2 t)/( _{2 2} c ₂ r _w ² ), non-dimensional - Y ₀, Y ₁ Bessel functions of the second kind, zero and first-order - z Distance z measured vertically upward from bottom of reservoir, cm, ft - Z _D z/r _w , non-dimensional - z ₁ Height of the bottom of the producing layer, cm, ft - z _1D z ₁/r _w , non-dimensional - z ₂ Height of the top of the producing layer, cm, ft - z _2,D z ₂/r _w , non-dimensional - _n nth positive root of equation (18) - ₁ k _z1/k _r1, non-dimensional - ₂ k _z2/k _r2, non-dimensional - _{1 1 1} c ₁/k _r1, hydraulic diffusivity of layer I - _{2 2 2} c ₂/k _r2, hydraulic diffusivity of layers II and III - ₂, ₁ Viscosity of oil and water, cp, cp - _{n n} /r _w , l/cm, l/ft - ₂, ₁ Porosity of oil and water-filled zones, fraction - ( ₁/ ₂) (k _z2/k _z1), non-dimensional     

Pressure dependence of the electrical resistivity and the ionization energy of Cr In n-type InP

The electrical resistance of chromium-doped, n-type InP has been found to increase exponentially with hydrostatic pressure (up to 4.7 kbar) at 273 K, 301 K, and 344 K. The resistivity activation energy increases by 6.5 × 10^-6 eV/bar. This rate equals the difference between the pressure dependences of the lowest conduction band minimum at $\text{k}$ = (000) and the <111> subsidiary minima determined by others. Our results indicate that pressure increases the ionization energy of a Cr donor level whose wave function has a large contribution from the <111> minima. It is suggested the Cr donor level is due to Cr⁺³ occupying an indium site.     

Energy Levels of Neutral Atoms Via a New Perturbation Method

The energy levels of neutral atoms supported by potential V (r) = -Zexp(-ar)/r (Yukawa potential) are studied, using both dimensional and dimensionless quantities, via a new analytical methodical proposal (devised to solve for nonexactly solvable Schrödinger equation). Using dimensionless quantities, by scaling the radial Hamiltonian through y = Zr and = /Z, we report that the scaled screening parameter is restricted to have values ranging from zero to less than 0.4. On the other hand, working with the scaled Hamiltonian enhances the accuracy and extremely speeds up the convergence of the energy eigenvalues. The energy levels of several new eligible scaled screening parameter values are also reported.     

Determination of polyphenol component fractions and integral antioxidant capacity of Syrian aniseed and fennel seed extracts using GC–MS,HPLC analysis,and photochemiluminescence assay

The chemical components of both Syrian aniseed and fennel seeds collected from Idlib and Aleppo regions were identified using GC/MS spectrometry. Thirty-four component fractions representing an average of 98.5% of anise seed extract were characterized. The major average components were (E)-Anethole, Estragole, Limonene, Fenchone, Linalool, para-Anisaldehyde, (Z)-Anethole, and methyl chavicol. Also, thirty-one component fractions representing an average of 99.46% of fennel seed extract were identified. The major components were α-Pinene, α-Phellandrene, Fenchone, Methyl chavicol, Estragole, (Z)-Anethole, Limonene, 1,8-Cineole, Anisole-p-allyl, E,E-Farnesene, Estragole, (E)-Anethole, Anisaldehyde, and Carvacrol. The extract of aniseed was characterized by higher amounts of trans-anethole (52.2%) than fennel extract (38.3%). The integral antioxidant capacity (IAC) of two different extracts from both aniseed and fennel seeds have been determined using photochemiluminescence assay (PCL). The sum of antioxidant capacity (IAC) of hydrophilic and hydrophobic components in both aniseed and fennel seeds was determined, as a total equivalent per gram of dry material (nmolTE/gDM) at 166.69 ± 0.42 and 363.28 ± 1.11 nmol for hydrophilic and hydrophobic components, respectively. Eight major phenolic compounds known as possible antioxidant sources with their concentrations have been identified in both aniseed and fennel seeds by HPLC and GC–MS analysis.     

Qualitative and quantitative ATR-FTIR analysis and its application to coal char of different ranks

This paper analyzes the coal to char stages of char formation of six coals of different ranks by using Fourier transform infrared coupled w ith attenuated total reflectance(ATR-FTIR).The chars w ere obtained by coal pyrolysis carried out at temperature range of 450~700℃.The data obtained show s the pragmatic disappearance of the aliphatic hydrogen content w ith increasing char formation temperature.Numerical evaluation of the spectra enabled the determination of aromaticity,fa.The aromaticity w as found to be betw een 0.66~0.79 for lignite,0.75~0.90 for sub-bituminous,0.84~1.00 for low volatile bituminous,0.83~1.00 for high volatile bituminous,0.94~1.00 for semi-anthracite,and 0.97~1.00 for anthracite respectively.With increasing rank of coal samples,spectra exhibit rising aromaticity and enhanced condensation of aromatic rings,w hereas the aliphatic chain lengths decrease.     

A reassessment of the vibrational spectrum of hydrogenated amorphous silicon

Paul [1] has cogently argued the case against the exclusive assignment of the 2100 cm^-1 band in the vibrational spectrum of hydrogenated amorphous silicon to =SiH₂ complexes. Data are presented in the present paper which make the grounds for dissent from the dihydride model less securely based. We assert that, for as-prepared r.f.a-Si films, the contribution to the 2100 cm^-1 band intensity from alternative structures is not as significant as hitherto proposed.     

X-ray diffraction and Mössbauer spectroscopy of high energy ball-milled α-Fe2O3/TiO2 composite powders

α–Fe₂O₃/TiO₂ Composite powders have been prepared by high energy ball-milling for different times. The composites were studied using Mössbauer Spectroscopy (MS) and X-ray diffraction (XRD). The patterns of XRD show broadening in the diffraction peaks, indicating a decrease in the particle size of the composites with milling time. Also, the XRD patterns show an evolving new structural phase correlated with an evolving Titanium ferrite species with milling time. Mössbauer Spectroscopy shows the evolving titanium ferrite species characterized by a quadrupole doublet at the expense of the α–Fe₂O₃ represented by the magnetic sextet. The doublet corresponding to the Ti-ferrite phase dominates the Mössbauer spectra at long milling time (greater than 100 h of milling).     

2D H-Atom in an Arbitrary Magnetic Field via Pseudoperturbation Expansions Through the Quantum Number l

The pseudoperturbative shifted-1 expansion technique is introduced to determine nodeless states of the 2D Schrodinger equation with arbitrary cylindrically symmetric potentials. Exact energy eigenvalues and eigenfunctions for the 2D Coulomb and harmonic oscillator potentials are reproduced. Moreover, exact energy eigenvalues, compared with those obtained by numerical solution (V.M. Villalba and R. Pino, J. Phys.: Condens. Matter 8 (1996) 80671, were obtained for the hybrid of the 20 Coulomli and oscillator potentials.     

Chlorine dioxide reduction by aqueous iron(II) through outer-sphere and inner-sphere electron-transfer pathways

The reduction of ClO(2) to ClO(2)(-) by aqueous iron(II) in 0.5 M HClO(4) proceeds by both outer-sphere (86%) and inner-sphere (14%) electron-transfer pathways. The second-order rate constant for the outer-sphere reaction is 1.3 x 10(6) M(-1) s(-1). The inner-sphere electron-transfer reaction takes place via the formation of FeClO(2)(2+) that is observed as an intermediate. The rate constant for the inner-sphere path (2.0 x 10(5) M(-1) s(-1)) is controlled by ClO(2) substitution of a coordinated water to give an inner-sphere complex between ClO(2) and Fe(II) that very rapidly transfers an electron to give (Fe(III)(ClO(2)(-))(H(2)O)(5)(2+))(IS). The composite activation parameters for the ClO(2)/Fe(aq)(2+) reaction (inner-sphere + outer-sphere) are the following: DeltaH(r)++ = 40 kJ mol(-1); DeltaS(r)++ = 1.7 J mol(-1) K(-1). The Fe(III)ClO(2)(2+) inner-sphere complex dissociates to give Fe(aq)(3+) and ClO(2)(-) (39.3 s(-1)). The activation parameters for the dissociation of this complex are the following: DeltaH(d)++= 76 kJ mol(-1); DeltaS(d)++= 32 J K(-1) mol(-1). The reaction of Fe(aq)(2+) with ClO(2)(-) is first order in each species with a second-order rate constant of k(ClO2)- = 2.0 x 10(3) M(-1) s(-1) that is five times larger than the rate constant for the Fe(aq)(2+) reaction with HClO(2) in H(2)SO(4) medium ([H(+)] = 0.01-0.13 M). The composite activation parameters for the Fe(aq)(2+)/Cl(III) reaction in H(2)SO(4) are DeltaH(Cl(III))++ = 41 kJ mol(-1) and DeltaS(Cl(III))++ = 48 J mol(-1) K(-1).     

Optimization of signal-to-noise ratio in integrated planar optical interconnects packages

The signal-to-noise ratio (SNR) of integrated planar optical (IPO) board-to-board interconnections system is analyzed. The SNR is derived as a function of separation between the boards, beam spot size, optical system efficiency, receiver thermal noise, thickness of the substrate, and the angle of propagation of the beam. Based on the analyses and the results obtained it is shown that the design of optical interconnects system can be optimized for maximum SNR using at least one parameter, namely, angle of propagation.