Journal articles on the topic 'Computer engineering, n.e.c'

Computer simulations have been used frequently to calculate design loads associated with a specific return period for offshore structures. However, two important questions persistently confront engineers who simulate load events on computers to estimate k-year forces: 1) How accurate is the estimated k-year force (say, 100-yr force) obtained through a computer simulation of n years (e.g., n = 1000) compared to that which would result from a much longer simulation? 2) When can we stop a computer simulation? Or how many simulation years are needed to reach a specified level of reliability for a certain k-year force? This paper presents solutions to these two questions under the assumption that the input parameters are completely known and the formulas used to compute loads are one hundred percent correct. Given a confidence level C (e.g., C = 80 or 90 percent) and an arbitrary but fixed number of simulation years, a method is identified to find an estimated k-year force and an error bound α, such that Pr(|estimator−k-yearforce|<α)>C (1) In addition, when the required confidence C and error bound α are given, a procedure is given to stop a computer simulation as soon as inequality (1) is satisfied. These results are not dependent on the statistical distribution of the underlying force distribution. Therefore, one does not have to assume that forces are of a specific probability distribution (such as lognormal, exponential, etc.).

Abstract Quantum computers hold unprecedented potentials for machine learning applications. Here, we prove that physical quantum circuits are probably approximately correct learnable on a quantum computer via empirical risk minimization: to learn a parametric quantum circuit with at most n c gates and each gate acting on a constant number of qubits, the sample complexity is bounded by O ~ ( n c + 1 ) . In particular, we explicitly construct a family of variational quantum circuits with O(n c+1) elementary gates arranged in a fixed pattern, which can represent all physical quantum circuits consisting of at most n c elementary gates. Our results provide a valuable guide for quantum machine learning in both theory and practice.

Analyzing large sparse electrical networks is a fundamental task in physics, electrical engineering and computer science. We propose two classes of quantum algorithms for this task. The first class is based on solving linear systems, and the second class is based on using quantum walks. These algorithms compute various electrical quantities, including voltages, currents, dissipated powers and effective resistances, in time poly(d, c,log(N), 1/λ, 1/e), where N is the number of vertices in the network, d is the maximum unweighted degree of the vertices, c is the ratio of largest to smallest edge resistance, λ is the spectral gap of the normalized Laplacian of the network, and e is the accuracy. Furthermore, we show that the polynomial dependence on 1/λ is necessary. This implies that our algorithms are optimal up to polynomial factors and cannot be significantly improved.

Reactor technology for the transesterification process of vegetable oils or animal fats with methanol has been widely developed to obtain biodiesel products that comply with standards but at the lowest cost. The hydrodynamic cavitation reactor with orifice type is a choice for this purpose. This research aims to determine the optimal orifice design from several orifice designs tested through CFD simulation. Computer simulations performed on orifices A, B, C and D using the Schnerr and Sauer models show that orifice C is optimal for cavitation at an absolute inlet pressure of 3x105 N/m2 with the use of methanol as fluid. The parameters studied in the computer simulation are velocity, pressure, turbulent kinetic energy and vapor volume fraction. At the absolute inlet pressure of 3x105 N/m2, the maximum speed is 28.69 m/s, the minimum pressure is 12266 N/m2, the maximum vapor volume fraction is 0.98, and the maximum turbulent kinetic energy is 12.75 m2/s2. The results of simulation were compared with experiments conducted on a hydrodynamic cavitation reactor using orifices C and D. Measurements of the velocity and pressure parameters showed that there were no significant deviations between the results of the computer simulation and the experiment.

Abstract : In the Philippines, students exhibit a low interest in entrepreneurship despite numerous programs implemented and mandated by the government. The emergence of technopreneurship is now confronted by several issues, mainly in developing competent and versatile technopreneurs. Until now, there are inadequate studies related to technopreneurship specifically those dealing with technopreneurial intention among engineering students. This study aims to determine the factors associated with technopreneurial intention. Simple random sampling was used to collect necessary data from 200 undergraduate engineering students from selected universities in the Philippines. Multiple Regression Analysis and Pearson Correlation Analysis were used to test the hypotheses and examine the relationship between independent and dependent variable respectively. The findings revealed that among the five identified factors, only Comput er Abi l ity, Access to Capi tal , and Entrepreneurial Experience have a significant and p o s i t i v e e f f e c t o n i n t e n t i o n t ow a r d s technopreneurship Keywords : Computer Ability; Entrepreneurial Experience; Entrepreneurial Orientation; Internet Ability; Technopreneurial Intention

We present two novel results for small damped oscillations described by the vector differential equation Mx¨+Cx˙+Kx=0, where the mass matrix M can be singular, but standard deflation techniques cannot be applied. The first result is a novel formula for the solution X of the Lyapunov equation ATX+XA=−I, where A=A(v) is obtained from M,C(v)∈Rn×n, and K∈Rn×n, which are the so-called mass, damping, and stiffness matrices, respectively, and rank(M)=n−1. Here, C(v) is positive semidefinite with rank(C(v))=1. Using the obtained formula, we propose a very efficient way to compute the optimal damping matrix. The second result was obtained for a different structure, where we assume that dim(N(M))≥1 and internal damping exists (usually a small percentage of the critical damping). For this structure, we introduce a novel linearization, i.e., a novel construction of the matrix A in the Lyapunov equation ATX+XA=−I, and a novel optimization process. The proposed optimization process computes the optimal damping C(v) that minimizes a function v↦trace(ZX) (where Z is a chosen symmetric positive semidefinite matrix) using the approximation function g(v)=cv+av+bv, for the trace function f(v)≐trace(ZX(v)). Both results are illustrated with several corresponding numerical examples.

The China Fusion Engineering Test Reactor (CFETR) is a tokamak device to validate and demonstrate fusion engineering technology. In CFETR, the breeding blanket is a vital important component that is closely related to the performance and safety of the fusion reactor. Neutronics/thermal-hydraulics (N/TH) coupling effect is significant in the numerical analysis of the fission reactor. However, in the numerical analysis of the fusion reactor, the existing coupling code system mostly adopts the one-way coupling method. The ignorance of the two-way N/TH coupling effect would lead to inaccurate results. In this paper, the MCNP/FLUENT code system is developed based on the 3D-1D-2D hybrid coupling method. The one-way and two-way N/TH coupling calculations for two typical blanket concepts, the helium-cooled solid breeder (HCSB) blanket and the water-cooled ceramic breeder (WCCB) blanket, are carried out to study the two-way N/TH coupling effect in CFETR. The numerical results show that, compared with the results from the one-way N/TH coupling calculation, the tritium breeding ration (TBR) calculated with the two-way N/TH calculation decreases by −0.11% and increases by 4.45% for the HCSB and WCCB blankets, respectively. The maximum temperature increases by 1 °C and 29 °C for the HCSB and WCCB blankets, respectively.

Variable temperature tapping mode atomic force microscopy is exploited to in situ visualize the morphological evolution of N, N'-di(naphthalene-1-yl)-N, N'-diphthalbenzidine (NPB) thin film. The apparent glass transition of the NPB thin film initially occurred at 60°C, proceeded until 95°C, and crystallization from the glassy state quickly appeared at 135°C. The NPB thin film gradually melted and disappeared when the temperature was above 175°C, revealing the underlying layer. These observations are technically helpful and significant to gauge the temperature dependent lifetime and luminance of organic light-emitting diodes.

Pauling et al. (1951, “The Structure of Proteins: Two Hydrogen-Bonded Helical Configurations of the Polypeptide Chain,” Proc. Natl. Acad. Sci. U.S.A., 37(4), pp. 205–211) in their seminal paper in 1951 reported numerical values for the bond lengths and bond angles for a peptide unit in proteins. These values became the standard model for several decades after that. In this paper, we have made an attempt to calibrate the values of these bond lengths and bond angles based on a systematic approach applied to a collection of proteins defined structurally in the protein data bank (PDB). Our method is based on the assumption that a peptide chain is a serial chain of identical rigid bodies connected by revolute joints (i.e., dihedral angles). Through an optimization process, the structural error (root mean square deviation of all atoms) between the resultant conformation and the PDB data is minimized to yield the best values for the bond length and bond angles in the calibrated peptide unit. Our numerical experiments indicate that by making small changes in the Pauling-Corey peptide model parameters (0.15–8.7%), the structural error is reduced significantly (3.0–57.4%). The optimum values for the bond angles and bond lengths are as follow; bond lengths: N–C(A): 1.4721Å, C(A)–C: 1.6167Å, C–N: 1.2047Å, CO: 1.1913Å and N–H: 0.9621Å. Bond bending angles: N–C(A)–C: 109.6823deg, C(A)–CO: 119.518deg, C(A)–C–N: 114.5553deg, OC–N: 125.9233deg, C–N–H: 123.5155deg, C–N–C(A): 121.5756deg, C(A)–N–H: 114.901deg peptide bond torsion angle: ω: 179.4432deg.

Au/GaN/GaAs Schottky diode created by the nitridation of n-GaAs substrate which was exposed to a flow of active nitrogen created by a discharge source with high voltage in ultra-high vacuum with two different thicknesses of GaN layers (0.7[Formula: see text]nm and 2.2[Formula: see text]nm), the I–V and capacitance–voltage (C–V) characteristics of the Au/n-GaN/n-GaAs structures were studied for low- and high-frequency at room temperature. The measurements of I–V of the Au/n-GaN/n-GaAs Schottky diode were found to be strongly dependent on bias voltage and nitridation process. The electrical parameters are bound by the thickness of the GaN layer. The capacitance curves depict a behavior indicating the presence of interface state density, especially in the low frequency. The interface states density was calculated using the high- and low-frequency capacitance curves and it has been shown that the interface states density decreases with increasing of nitridation of the GaAs.

Let Pc(x)={p≤x|p,[pc]areprimes},c∈R+∖N and λsym2f(n) be the n-th Fourier coefficient associated with the symmetric square L-function L(s,sym2f). For any A>0, we prove that the mean value of λsym2f(n) over Pc(x) is ≪xlog−A−2x for almost all c∈ε,(5+3)/8−ε in the sense of Lebesgue measure. Furthermore, it holds for all c∈(0,1) under the Riemann Hypothesis. Furthermore, we obtain that asymptotic formula for λf2(n) over Pc(x) is ∑p,qprimep≤x,q=[pc]λf2(p)=xclog2x(1+o(1)), for almost all c∈ε,(5+3)/8−ε, where λf(n) is the normalized n-th Fourier coefficient associated with a holomorphic cusp form f for the full modular group.

Problem solving skills are very important in supporting social development. Children with problem solving skills can build healthy relationships with their friends, understand the emotions of those around them, and see events with other people's perspectives. The purpose of this study was to determine the implementation of playing unplugged coding programs in improving early childhood problem solving skills. This study used a classroom action research design, using the Kemmis and Taggart cycle models. The subjects of this study were children aged 5-6 years in Shafa Marwah Kindergarten. Research can achieve the target results of increasing children's problem-solving abilities after going through two cycles. In the first cycle, the child's initial problem-solving skills was 67.5% and in the second cycle it increased to 80.5%. The initial skills of children's problem-solving increases because children tend to be enthusiastic and excited about the various play activities prepared by the teacher. The stimulation and motivation of the teacher enables children to find solutions to problems faced when carrying out play activities. So, it can be concluded that learning unplugged coding is an activity that can attract children's interest and become a solution to bring up children's initial problem-solving abilities. Keywords: Early Childhood, Unplugged Coding, Problem solving skills References: Akyol-Altun, C. (2018). Algorithm and coding education in pre-school teaching program integration the efectiveness of problem-solving skills in students. Angeli, C., Smith, J., Zagami, J., Cox, M., Webb, M., Fluck, A., & Voogt, J. (2016). A K-6 Computational Thinking Curriculum Framework: Implications for Teacher Knowledge. Educational Technology & Society, 12. Anlıak, Ş., & Dinçer, Ç. (2005). 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Elimination ideals are regarded as a special type of Borel type ideals, obtained from degree sequence of a graph, introduced by Anwar and Khalid. In this paper, we compute graphical degree stabilities of K n ∨ C m and K n ∗ C m by using the DVE method. We further compute sharp upper bound for Castelnuovo–Mumford regularity of elimination ideals associated to these families of graphs.

Robust optimal design of circulation systems (e.g., roads for vehicles or corridors for pedestrians) relies on an accurate steady-state traffic flow model that considers the effect of randomly changing environmental factors (e.g., daily periodicity and weather). Most analytical models assume that the customer interarrival time and service time of circulation facilities follow the exponential distribution with fixed rate parameters, which is unrealistic in most cases. In this paper, we develop a stationary PH i /PH i , n / C / C state-dependent queuing model in a randomly changing environment (RE), which is represented by a Markov chain. The model simultaneously considers the general randomness of arrival and service, the randomly varying rate parameters, and the state-dependent service (the travel time increases with the number of customers). The existing matrix analytic scheme (MAS) algorithm is extended to solve the proposed model because it avoids the explicit calculation of probability distributions. The space complexity of the algorithm is only linear in the number of RE states and is independent of the enormous (four-dimensional) state space of the Markov process. Its time complexity is a linear function of the product of the queue capacity and the number of RE states. Our model is validated versus simulation estimates. The obtained conditional performance measures can accurately capture the queue accumulation and dissipation and reveal the effect of randomly changing environments. Numerical experiments provide some interesting findings. (1) The proposed stationary model coincides with the transient M( t )/G x / C / C fluid queuing model under special conditions. (2) Under high traffic intensities, increasing the randomness in the duration time of the RE state leads to an obvious growth in the conditional queue length. (3) An increase in the facility length leads to an increase or a decrease in the average output rate, depending on whether the congestion dissipates effectively in one cycle. (4) A larger width is required to obtain the maximum average output rate for traffic demand with a greater nonuniformity.

The real forms of complex groups (or algebras) are important in physics and mathematics. The Lie group SL2,C is one of these important groups. There are real forms of the classical Lie group SL2,C and the quantum group SL2,C in the literature. Inspired by this, in our study, we obtain the real forms of the fractional supergroups shown with A3NSL2,C, for the non-trivial N = 1 and N = 2 cases, that is, the real forms of the fractional supergroups A31SL2,C and A32SL2,C.

Let (tn(r))n≥0 be the sequence of the generalized Fibonacci number of order r, which is defined by the recurrence tn(r)=tn−1(r)+⋯+tn−r(r) for n≥r, with initial values t0(r)=0 and ti(r)=1, for all 1≤i≤r. In 2002, Grossman and Luca searched for terms of the sequence (tn(2))n, which are expressible as a sum of factorials. In this paper, we continue this program by proving that, for any ℓ≥1, there exists an effectively computable constant C=C(ℓ)>0 (only depending on ℓ), such that, if (m,n,r) is a solution of tm(r)=n!+(n+1)!+⋯+(n+ℓ)!, with r even, then max{m,n,r}<C. As an application, we solve the previous equation for all 1≤ℓ≤5.

Предложено правило построения нового класса быстрых ортогональных преобразований – матриц C, порядков n = (2k)2 и n = (3•2k)2, k = 1, 2, … построенных на основе совершенных двоичных решеток порядков N = 2k, либо N = 3•2k. Показано, что бинарные ортогональные матрицы C обладают практически привлекательным свойством многопелевого циклического сдвига (N-сдвига), что обеспечивает эффективную процедуру скользящего метода расчета коэффициентов преобразования.

Background: The aim of this study was to analyze the effects of the time of use (TU) and sterilization cycles (SC) of endodontic reciprocating files on cyclic fatigue resistance. Methods: One-hundred-and-twenty (120) Procodile NiTi endodontic reciprocating instruments were selected at random and distributed into the following study groups: A: 0 sterilization cycles/0s time of use (n = 10); B: 0/60 (n = 10); C: 0/120 (n = 10); D: 1/0 (n = 10); E: 1/60 (n = 10); F: 1/120 (n = 10); G: 5/0 (n = 10); H: 5/60 (n = 10); I: 5/120 (n = 10); J: 10/0 (n = 10); K: 10/60 (n = 10); and L: 10/120 (n = 10). A dynamic cyclic fatigue device was designed using computer-aided design/computer-aided engineering (CAD/CAE) technology and created with a 3D printer to simulate the pecking motion performed by the clinician. Failure of the endodontic rotary instrument was detected by a light-emitting diode-light-dependent resistor (LED-LDR) system controlled by an Arduino driver complex and management software. The results were analyzed using the ANOVA test. Results: All pairwise comparisons presented statistically significant differences between the time to failure, number of cycles to failure and number of cycles of in-and-out movement for the time of use study groups (p < 0.001), but not in the number of sterilization cycles (p > 0.05). Conclusions: The time of use of NiTi endodontic reciprocating files negatively affects dynamic cyclic fatigue resistance. Dynamic cyclic resistance is not affected by the number of sterilization cycles.

Let Q be a positive defined n×n matrix and Q[x̲]=x̲TQx̲. The Epstein zeta-function ζ(s;Q), s=σ+it, is defined, for σ>n2, by the series ζ(s;Q)=∑x̲∈Zn\{0̲}(Q[x̲])−s, and is meromorphically continued on the whole complex plane. Suppose that n⩾4 is even and φ(t) is a differentiable function with a monotonic derivative. In the paper, it is proved that 1Tmeast∈[0,T]:ζ(σ+iφ(t);Q)∈A, A∈B(C), converges weakly to an explicitly given probability measure on (C,B(C)) as T→∞.

Topological index is a numerical parameter which characterizes the topology of the molecular structure. Topological indices are a very prominent part of the study of chemical structures in which properties of organic or inorganic compounds are under observation and calculated such as physical properties, chemical reactivity, or biological activity. Most of the topological indices of molecular graph-based structure which depends on vertex degrees have been visualized. In this study, we compute some degree-based topological indices of zirconium tetrachloride Z n C l 4 m , n .

Biomaterial-based nanofibrous scaffolds are the most effective alternative to bone transplantation therapy. Here, two recombinant minor ampullate spidroins (spider silk proteins), R1SR2 and NR1SR2C, were blended with Poly(lactic-co-glycolic) Acid (PLGA), respectively, to generate nanofiber scaffolds by electrospinning. The N-terminal (N), C-terminal (C), repeating (R1 and R2) and spacer (S) modules were all derived from the minor ampullate spidroins (MiSp). The physical properties and structures of the blended scaffolds were measured by scanning electron microscopy (SEM), water contact angle measurement, Fourier transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), and Tensile mechanical testing. The results showed that blending of MiSp (R1SR2 and NR1SR2C) reduced the diameter of nanofibers, increased the porosity and glass transition temperatures of nanofibrous scaffolds, and effectively improved the hydrophilicity and ultimate strain of scaffolds. It is worth noting that the above changes were more significant in the presence of the N- and C-termini of MiSp. In cell culture assays, human bone mesenchymal stem cells (HBMSCs) grown on NR1SR2C/PLGA (20/80) scaffolds displayed markedly enhanced proliferative and adhesive abilities compared with counterparts grown on pure PLGA scaffolds. Jointly, these findings indicated recombinant MiSp/PLGA, particularly NR1SR2C/PLGA (20/80) blend nanofibrous scaffolds, is promising for bone tissue engineering.

Improving the microwave absorption performance of Co-MOF-derived Co@N-C composite by constructing the morphology and spatial structure is a known challenge. In this work, under the action of the binder polyvinylpyrrolidone, 3D-graphene particles can be well decorated on the surface of the Co@N-C composite after high-temperature pyrolysis. In addition, due to the structural characteristics of MOFs, Co particles can be well covered by a carbon layer, which effectively solves the problem that magnetic metal particles are prone to corrosion and oxidation. The microwave absorption performances of the composite can be well adjusted by changing the average dotted density of the 3D-graphene on the Co@N-C composite. It is worth noting that the maximum reflection loss can reach −58.72 dB at the thickness of 1.64 mm, and the maximum effective absorption bandwidth can achieve 5.74 GHz at the 1.79 mm thickness, which almost covers the whole Ku band. Importantly, these results demonstrate that 3D-graphene@C/Co@N-C composites have great potential as high-efficiency microwave absorption materials.

Unexpectedly high concentrations of NO2 formation have been noted in stack emissions from industrial combustors. NO2 formation has been reported to occur through the so-called “HO2 mechanism” in which NO combines with HO2 to produce NO2 and OH In this study, the formation of NO2 was investigated at superatmospheric pressures through experiments and computer modeling. Computer modeling utilized the CHEMKIN chemical kinetics program and a subset of a previously published C–H–O–N system mechanism. Experimental work was conducted using a high-pressure flow reactor designed and built in the course of the study. The effects of pressure, temperature, and the presence of a NO2-promoting hydrocarbon, methane, were investigated. It was discovered that as pressure increased from 1 atm to 8.5 atm, the rate and amount of NO converted to NO2 also increased. The results also show a temperature “window” between approximately 800 K and 1000 K in which NO to NO2 conversion readily occurred. The presence of methane was seen to enhance NO conversion to NO2, and a ratio of [CH4]/[NO] was found to be a useful parameter in predicting NO2 formation. Significant NO conversion to NO2 was noted for [CH4]/[NO] > 1 at the hydrocarbon injection point. Experimental results validated those trends obtained from modeling with a modified C–H–O–N mechanism.

A new solution for the dynamic analysis of asphalt concrete pavements subjected to moving fluctuating loads has been developed. The method builds on an existing model for stationary loads, SAPSI, which uses the complex response method of transient analysis with a continuum solution in the horizontal direction and a finite-element solution in the vertical direction. The structural model is an n-layered damped-elastic medium. The subgrade can be modeled as either a rigid base or a semi-infinite half space. The loads are surface pressure loads, and the analysis is under axisymmetric conditions. The moving loads are modeled as a series of pulses with a duration equal to the time required for the wheel to pass a fixed point in the pavement. The proposed method of analysis in the new version of the program, SAPSI-M, is an improvement over the existing methods because (a) it treats moving fluctuating loads on an n-layered damped-elastic system; (b) it incorporates such important factors as wave propagation, inertia, and damping effects of the medium, as well as frequency-dependent asphalt concrete properties; and (c) it can handle any load configuration, thus making possible the modeling of multiple wheel configurations of truck axles and airplane landing gears. Theoretical results have shown that the effect of vehicle speed is significant, in part due to the frequency-dependent properties of the asphalt concrete. Comparison with field strain data from full-scale pavement tests has shown excellent agreement.

Problems of welding in shipbuilding - an analytic-numerical assessment of the thermal cycle in HAZ with three dimensional heat source models in agreement with modelling rules This part is continuation of PART II. Analytic solutions for the temperature distribution in HAZ - presented in the previous part of this article are transformed for computer calculation with used Mathcad programme. There are established algorithms in moving and stationary systems for thermal cycle calculating. Finally, a few analytical examples with use of C-I-N and D-E models are demonstrated.

Abstract The efficiency of D4 Gaussian elimination on a vector computer, the Cray- 1/S, it examined. The algorithm used in this work is employed routinely in Phillips Petroleum Co. reservoir simulation models. Comparisons of scalar Phillips Petroleum Co. reservoir simulation models. Comparisons of scalar and vector Cray-1/S times are given for various example cases including multiple unknowns per gridblock. Vectorization of the program on the Cray- 1/S is discussed. Introduction In reservoir simulation, the solution of large systems of linear equations accounts for a substantial percentage of the computation time. Methods used today consist of both iterative and direct solution algorithms. Because of the theoretical savings in both storage and computing labor, D4 Gaussian elimination is a popular direct solution algorithm and is used widely on conventional scalar computers. In this paper we investigate the efficiency of the D4 algorithm on a computer with vector processing capabilities-the Cray-1/S. The D4 (or alternate diagonal) algorithm originally was presented by Price and Coats in 1973. Since that time much work has been done on the Price and Coats in 1973. Since that time much work has been done on the algorithm including an investigation by Nolen on the vector performance of D4 on the CDC Star 100 and Cyber 203 on single-unknown-per-gridblock example cases. Levesque has presented a comparison of the Cray-1 and Cyber 205 in reservoir simulation that includes the D4 algorithm. Vector performance of the Cray-1 on linear algebra kernels, both sparse and dense, performance of the Cray-1 on linear algebra kernels, both sparse and dense, also has been reported. Vector performance on these kernels typically is expressed in terms of million floating point operations per second (MFLOPS). Our objective here is to evaluate vector performance on a typical production code written in FORTRAN for a scalar computer. Therefore, performance, or efficiency, will be evaluated in terms of both scalar and vector CPU times on the Cray-1/S. We include vector performance on the original code with automatic vectorization enabled, and vector performance on the same code with minor restructuring, automatic performance on the same code with minor restructuring, automatic vectorization enabled, and the use of Cray assembly language (CAL) basic linear algebra kernels. Example cases for multiple unknowns per gridblock are presented. Reservoir Flow Equations The reservoir flow equations written using a seven-point finite difference formulation can be expressed as ...........................(1) where the terms A, B... G are matrices of order N equal to the number of unknowns per gridblock. represents the vector of unknowns at cell i, j, k, and H is the vector of residuals of the flow equations at cell i, j, k at iteration . Values of N from 1 to 10 typically are encountered depending on the type of simulator and the degree of implicitness used. For example, N is equal to one for an implicit pressure, explicit saturation (IMPES) black-oil model; three for a fully implicit black-oil model; five for an implicit three-component steamflood model and usually 10 or less for an implicit compositional model. Driver Program To facilitate timing studies in this work, a driver program was written to calculate coefficients for the D4 Gaussian elimination routine. Input to the program consists of grid dimensions and the number of unknowns per gridblock. All elements of the off-diagonal matrices (A, C, D... G) were set equal to 1. To guarantee a nonsingular solution, the B matrix was set equal to -5 for one unknown and as below for N unknowns. ............................(2) Right-side coefficients, H, were calculated by assuming a unit solution for . No-flow boundary conditions were used, which require specific matrices, such as A for I = 1 and C for I = NX, to be set equal to zero. Description of Hardware and Software All run times reported in this work were obtained on the Cray-1/S, Serial No. 23, at United Computing Systems in Kansas City, MO. Serial No. 23 contains 1 million 64-bit words of central memory interleaved in 16 memory banks and no input/output (I/O) subsystems. The FORTRAN compiler used was CFT 1.09. CPU times were obtained by calling SECOND, a FORTRAN-callable utility routine that returns CPU time since the start of the job in FPS'S. CPU overhead incurred for each call to SECOND is approximately 2.5 microseconds. For all reported Cray-1/S times, "vector" refers to the original FORTRAN code run with automatic vectorization enabled, which is the normal operating mode. SPEJ p. 121

Motion planning is a major problem in robotics. The objective is to plan a collision-free path for a robot moving through a workspace populated with obstacles. In this paper, we present a fast and practical algorithm for moving a convex polygonal robot among a set of polygonal obstacles with translations and rotations. The running time is O(c((n + k)N + n log n)), where c is a parameter controlling the precision of the results, n is the total number of obstacle vertices, k is the number of intersections of configuration space obstacles, and N is the number of obstacles, decomposed into convex objects. This work builds upon the slabbing method proposed by Ahrikencheikh et al. [2], which finds an optimal motion for a point among a set of nonoverlapping obstacles. Here, we extend the slabbing method to the motion planning of a convex polygonal robot with translations and rotations, which also allows overlapping configuration space obstacles. This algorithm has been fully implemented and the experimental results show that it is more robust and faster than other approaches.

N-(dimethoxyphosphoryl)-1-methylpyridinium-4-carboximidate, a new carbacylamidophosphate-type compound, was synthesized and characterized by means of IR, 1H and 31P NMR and UV-Vis spectroscopies and X-ray analysis. The molecule of the synthesized compound has triclinic (P-1) symmetry, displays monomeric motif in crystal and crystalizes as solvate containing methanol molecule, which is connected to carbacylamidophosphate molecule through O(2)H(5A)–O(5) hydrogen bond. Through – stacking interactions, the molecules of the synthesized compound are linked in the chain along the a crystallographic axis. Several other intermolecular bonds connect these chains along b and c crystallographic axes. The intermolecular interactions with HH and OH contacts prevail in the crystalline structure of N-(dimethoxyphosphoryl)-1-methylpyridinium-4-carboximidate, the contribution of planar stacking CC contacts being equal to 4.1%. The synthesized compound was found to be well soluble in water. By using computer program PASS, we established that the synthesized substance is likely can exhibit 18 types of biological activity in experiment.

Abstract This study elucidates the effects of composition and temperature on the rheological behavior of chocolate milk formulation. The fat [0.5, 1 and 1.5 g] and xanthan gum contents [0.05, 0.1 and 0.15 g] varied and shear stress-strain rate data were recorded at varying temperature [21.4, 65 and 80 °C]. All compositions showed predominantly a pseudoplastic behavior [i.e., pseudoplasticity index, n < 1] with a strong influence on composition and temperature. Three semi-empirical rheological models, i.e. Power-law, Herschel–Bulkely, and Casson models were fitted on the data using an in-house developed computer program for the best statistical fit. The pseudoplasticity index [n] varied with the composition that initially decreased with temperature and subsequently increased. The other model parameters such as consistency index [k], Casson and Herschel–Bulkely yield stress, and Casson viscosity [at a specified rate i.e., 34.7 s−1] were computed through model fitting and correlated to the microstructural changes inside the fluid keeping in view the composition and temperature. This study helps in correlating chocolate milk processing and quality control based on complex microstructure to the rheological parameters measured at simulated temperatures and shear rates.

We study the influence of a unit Killing vector field on geometry of Riemannian manifolds. For given a unit Killing vector field w on a connected Riemannian manifold (M,g) we show that for each non-constant smooth function f∈C∞(M) there exists a non-zero vector field wf associated with f. In particular, we show that for an eigenfunction f of the Laplace operator on an n-dimensional compact Riemannian manifold (M,g) with an appropriate lower bound on the integral of the Ricci curvature S(wf,wf) gives a characterization of the odd-dimensional unit sphere S2m+1. Also, we show on an n-dimensional compact Riemannian manifold (M,g) that if there exists a positive constant c and non-constant smooth function f that is eigenfunction of the Laplace operator with eigenvalue nc and the unit Killing vector field w satisfying ∇w2≤(n−1)c and Ricci curvature in the direction of the vector field ∇f−w is bounded below by n−1c is necessary and sufficient for (M,g) to be isometric to the sphere S2m+1(c). Finally, we show that the presence of a unit Killing vector field w on an n-dimensional Riemannian manifold (M,g) with sectional curvatures of plane sections containing w equal to 1 forces dimension n to be odd and that the Riemannian manifold (M,g) becomes a K-contact manifold. We also show that if in addition (M,g) is complete and the Ricci operator satisfies Codazzi-type equation, then (M,g) is an Einstein Sasakian manifold.

Purpose This paper aims to present a triple-band monopole antenna design of 0.2-mm thickness with an overall dimension of 21 × 8 mm2 for wireless local area network (WLAN)/worldwide interoperability for microwave access (WiMAX) multiple input and multiple output (MIMO) applications in the laptop computer. Design/methodology/approach It comprises three monopole radiating elements, namely, strip AD (inverted C), strip EG (inverted J) and strip FI (inverted U) along with two rectangular open-end tuning stubs, namely, “m” and “n” of size 1.5 × 0.9 mm2 and 1.8 × 0.9 mm2, respectively. The proposed structure is compact, cost-effective and easy to integrate inside the laptop computers. Findings This structure excites three WLAN (2.4/5.2/5.8 GHz) and three WiMAX (2.3/3.3/5.5 GHz) bands. The proposed antenna array elucidates that it has measured −10dB impedance bandwidth of 11.86 per cent (2.22-2.50) GHz in a lower band (f_l), 6.83 per cent (3.25-3.48) GHz in medium band (f_m) and 16.84 per cent (5.00-5.92) GHz in upper band (f_u). The measured gain and radiation efficiency are above 3.64dBi and 75 per cent, respectively, and isolation better than −20dB. The envelope correlation coefficient (ECC) is less than 0.004. The simulated and measured results are in good concurrence, which confirms the applicability of the proposed antenna array for MIMO applications in the laptop computer. Originality/value The proposed antenna is designed without using vias, reactive elements and matching circuits for excitation of WLAN/WiMAX bands in the laptop computers. The design also does not require any additional ground for mounting the antenna. Further, the antenna array, formed by using the same antenna design, does not need additional isolating elements and is designed in such a way that the system ground itself acts as an isolating element. The proposed antenna has a low profile and is ultra-thin, cost-effective and easy to manufacture and can be easily embedded inside the next-generation laptop computers.

The present study aimed to determine the kinetics of pollutant removal in biofilters with LECA filling (used as a buffer to prevent de-icing agents from being released into the environment with stormwater runoff). It demonstrated a significant effect of temperature and a C/N ratio on the rate of nitrification, denitrification, and organic compound removal. The nitrification rate was the highest (0.32 mg N/L·h) at 25 °C and C/N = 0.5, whereas the lowest (0.18 mg N/L·h) at 0 °C and C/N = 2.5 and 5.0. Though denitrification rate is mainly affected by the available quantity of organic substrate, it actually decreased as the C/N increased and was positively correlated with the temperature levels. Its value was found to be the highest (0.31 mg N/L·h) at 25 °C and C/N = 0.5, and the lowest (0.18 mg N/L·h) at 0 °C and C/N = 5.0. As the C/N increased, so did the content of organic compounds in the treated effluent. The lowest organic removal rates were noted for C/N = 0.5, ranging between 11.20 and 18.42 mg COD/L·h at 0 and 25 °C, respectively. The highest rates, ranging between 27.83 and 59.43 mg COD/L·h, were recorded for C/N = 0.5 at 0 and 25 °C, respectively.

This paper deals with Lopatinskii type boundary value problem (bvp) for the (poly) harmonic differential operators. In the case of Robin bvp for the Laplace equation in the ball B1 a Green function is constructed in the cases c>0, c∉−N, where c is the coefficient in front of u in the boundary condition ∂u∂n+cu=f. To do this a definite integral must be computed. The latter is possible in quadratures (elementary functions) in several special cases. The simple proof of the construction of the Green function is based on some solutions of the radial vector field equation Λu+cu=f. Elliptic boundary value problems for Δmu=0 in B1 are considered and solved in Theorem 2. The paper is illustrated by many examples of bvp for Δu=0, Δ2u=0 and Δ3u=0 in B1 as well as some additional results from the theory of spherical functions are proposed.

We discuss the sharp focusing of an initial hybrid vector light field of the n-th order that has n C-lines (lines along which the polarization is circular). Using a complex Stokes field, it is shown that the polarization singularity index of such a field is equal to n / 2. The initial field is shown to retain it singularity index in the focal plane. Analytical expressions are obtained for the intensity and Stokes vector components in the focal plane. It is shown theoretically and numerically that for an even-order field with n = 2p, the intensity pattern at the focus has symmetry and instead of C-lines, C-points are formed, with the axes of polarization ellipses rotating around them. For n = 4, there are C-points with singularity indices 1/2 and with a “lemon” topology. Around such points, a surface that is formed by the polarization ellipses in a three-dimensional space has a Möbius strip topology. For an odd-order initial field with n = 2p +1, the intensity pattern at the focus is shown to have no symmetry, with the field becoming pure vectorial (no elliptical polarization) and the linear polarization vectors rotating around V-points.

For any perfect matching M of a graph AG, the anti-forcing number of Maf(G,M) is the cardinality of a minimum edge subset S⊆E(G)∖M such that the graph G−S has only one perfect matching. The anti-forcing numbers of all perfect matchings of G form its anti-forcing spectrum, denoted by Specaf(G). For a convex hexagonal system O(n1,n2,n3) with n1≤n2≤n3, denoted by H, it has the minimum anti-forcing number n1. In this paper, we derive a formula for its maximum anti-forcing number Af(H), i.e., the Fries number. Next, we prove that [n1,c]∪{c+2,c+4,…,Af(H)−2,Af(H)}⊆Specaf(H) for the specific integer c with the same parity as Af(H). In particular, we obtain that if n1+n2−n3≤1, then c=Af(H), which implies that Specaf(H)=[n1,Af(H)] is an integer interval. Finally, we also give some non-continuous situations: Specaf(O(2,n,n))=[2,4n−2]∖{4n−3} for n≥2; the anti-forcing spectrum of H has a gap Af(H)−1 for n1=n2≥2 and n3 even, or n2=n3 and n1≥2 even.