One-dimensional Equivalent Research Articles

SEISMIC RESPONSE IN MUARA BANGKAHULU SUB-DISTRICT, BENGKULU CITY, USING THE CONCEPT OF WAVE PROPAGATION

The position of Bengkulu Province, which is flanked by the subduction zone between the Euro-Asian and Indian-Australian plates to the west, and the Sumatra Fault zone to the east, makes Bengkulu City one of the areas prone to earthquake disasters. Muara Bangkahulu District is one of the sub-districts in Bengkulu City. Muara Bangkahulu sub-district is an area that functions as a government centre, trade and service centre, and one of the education centres in Bengkulu City. This study aims to determine the ground response in the Muara Bangkahulu sub-district area during an earthquake. The wave propagation method used in this study is a one-dimensional equivalent of linear and nonlinear modelling that propagates earthquake waves from bedrock to surface. The results of this study are Peak Ground Acceleration (PGA), amplification factor, earthquake acceleration time history, and acceleration spectra response. The results of this analysis will be compared between equivalent linear and nonlinear values. The results of this study can also help us realise and further consider the value of seismic design in the Muara Bangkahulu sub-district area, mainly if a stronger earthquake occurs in the future.

One-dimensional equivalence ratio measurements by femtosecond laser filament-triggered discharge plasma spectroscopy

Equivalence ratio measurements are of great importance for combustion systems. In this paper, femtosecond laser filament-triggered discharge plasma spectroscopy is proposed for one-dimensional equivalence ratio measurements of combustion flow fields. The optical emission spectra of femtosecond laser filament-triggered discharge plasma in methane-air premixed laminar flames were measured. The spectral intensity ratios of different species show a linear correlation with the equivalence ratio. It can be demonstrated that femtosecond laser filament-triggered discharge plasma spectroscopy can be used for equivalence ratio measurements. We investigated the effect of the temperature of the methane-air mixture on the equivalence ratio measurements. We further analyzed the one-dimensional spatial intensity distributions of the plasma spectral lines. The results demonstrated the capability of femtosecond laser filament-triggered discharge plasma spectroscopy for one-dimensional equivalence ratio measurements. Finally, femtosecond laser filament-triggered discharge plasma spectroscopy was applied to a methane diffusion flame and measured the one-dimensional equivalence ratios of the diffusion flame at different heights. Femtosecond laser filament-triggered discharge plasma spectroscopy offers a new method for one-dimensional equivalence ratio measurements of combustion flow fields.

Instantaneous one-dimensional equivalence ratio measurements in methane/air mixtures using femtosecond laser-induced plasma spectroscopy.

Equivalence ratio is one of the most significant parameters in combustion flow fields. In this paper, femtosecond laser-induced plasma spectroscopy (FLIPS) technique for instantaneous one-dimensional local equivalence ratio measurements were performed. By measuring the spatially resolved spectra of FLIPS, we found that the spectral peak area ratios of CH (431 nm)/N2 (337 nm), CH (431 nm)/N2 (357 nm), and CH (431 nm)/O (777 nm) can be utilized to achieve one-dimensional local equivalence ratio measurements. Among them, the CH peak at ~431 nm and the O peak at ~777 nm are strong enough to be used to achieve single-shot measurements, which is important to turbulent flow fields. Furthermore, systematic experiments were performed by using FLIPS in both laminar and turbulent flow fields. The FLIPS technique features the abilities of instantaneous one-dimensional quantitative measurements, high spatial resolution, and no Bremsstrahlung interference.

Online Precoding for Energy Harvesting Transmitter With Finite-Alphabet Inputs and Statistical CSI

This paper considers an online multiantenna precoder design for energy harvesting transmitter based on finite-alphabet inputs and statistical channel state information (CSI). It formulates the problem by maximizing the sum of average mutual information (AMI) of multiple time slots in one channel frame with causal energy constraint. The formulated problem is a $\mbox{2}N_{t}^{2}$ - dimensional stochastic dynamic programming (SDP) problem with a nonconcave objective function, where $N_{t}$ is the number of transmit antennas. The $\mbox{2}N_{t}^{2}$ - dimensional SDP problem is prohibitively complex and prevents the development of online algorithm for multiantenna systems. We provide equivalence between the multidimensional SDP problem and a one-dimensional power choice problem. Solving the one-dimensional equivalence decreases the computational burden extraordinarily without loss of optimality. We separate the one-dimensional problem into two cases: 1) the discrete-battery-state–discrete-power-choice (DBDP) problem and 2) the continuous-battery-state–continuous-power-choice (CBCP) problem. We also develop numerical algorithms to solve them, respectively. We further analyze the computational complexity of the developed algorithms and demonstrate the significant performance gains offered by the proposed method when compared with other methods.

Non-stationary compressible flow in ducts with varying cross-section

A comparative study of the interaction of shock wave or rarefaction wave with a converging duct separating long constant cross-section segments is presented. Quasi-one-dimensional computations are compared with fully two-dimensional computations. It is observed that in some cases the two-dimensional results approach the respective one-dimensional approximations over long times, while in other cases the two-dimensional computed flow is genuinely two-dimensional and cannot be reduced to a one-dimensional equivalent. In the latter cases, significant errors are incurred by analysing the flow using the quasi-one- dimensional duct flow approximation.

Shear force predictions from RBF corrected QUAD4 elements

The four-node plate bending element (QUAD4) is the workhorse element in all production run FEA work. Its performance in most applications as measured by convergence of deflections under loads is limited by the simple bilinear functions used. Attempts have been made to enhance its performance by introducing what is called the residual bending flexibility (RBF) correction.”’ Since these elements have a provision to include shear deformation, the RBF correction takes advantage of this fact by modifying the shear energy term to compensate for the deficient bending energy term so that superior performance is obtained. Recently it was shown that this is strictly an extra-variational trick (or ‘crime’), using as an example the two node beam element, which is the one-dimensional equivalent of the QUAD4 element. It is not difficult to argue from this that the RBF correction, as it is frequently applied to QUAD4 elements, will also disturb some properties of its performance, and especially its accuracy in stress prediction. Our short exercise here is motivated from this point of view. Expected (predicted) results will be compared with observed (computed) results using QUAD4 elements with and without RBF correction to substantiate our argument.

Unstable wavetrains and chaotic wakes in reaction-diffusion systems of λ-ω type

Periodic wavetrains are the one-dimensional equivalent of spiral waves and target patterns, and play a crucial role in the dynamics of oscillatory reaction-diffusion equations. I consider the behaviour of a λ-ω system of reaction-diffusion equations on a one-dimensional finite spatial domain with boundary conditions corresponding to the forcing of a particular periodic wavetrain. I derive a condition for the wavetrain itself to be a stable solution, and present numerical evidence for a complex sequence of bifurcations in the unstable region of parameter space. Finally I discuss the implications of the results for the phenomenon of irregular wakes behind transition waves in reaction-diffusion equations.

Use of artificial viscosity in multidimensional fluid dynamic calculations

The von Neumann-Richtmyer concept of artificial viscosity that is used in calculating the propagation of shocks was formulated in one space-dimension. A generalization of the method for two and for three space-dimensions is presented here. The basic objectives were to find the one-dimensional equivalent of shock compression that avoided geometric convergence effects and to determine a characteristic grid length. A description is given of a linear viscosity for damping the spurious oscillations that arise when the quadratic von Neumann-Richtmyer artificial viscosity is used. The linear viscosity minimizes the smearing of the shock front. Unwanted distortions that can occur in multidimensional grids are discussed. Results in two and three dimensions are given for the Navier-Stokes-type viscosity developed to damp these distortions.

Micro-evolution in a polymorphic prosobranch snail ( Clithon oualaniensis (Lesson))

The polymorphic brackish-water snail Clithon oualaniensis is widely spread in the Indo-Pacific Region. It has been studied in India and Ceylon, round the Malay Peninsula, and in Hong Kong; a smaller material from NE Queensland, Australia, has also been examined. The total is not far short of 100000 individuals. There are great geographical differences in gene frequencies. For instance, ‘purple spirals’ is polymorphic with an incidence of about 16% in NE Queensland (650 km of coastline), 5.5% round the Malay Peninsula (1500 km) and 2% on the east coasts of India and Ceylon (1400 km); but an abrupt drop to near-absence occurs in the Gulf of Mannar and persists as far as Goa on the Indian west coast (another 1400 km). The incidence thus falls from a polymorphic to a monomorphic level. Most variants are polymorphic in parts of the range and monomorphic in others. As large areas remain to be explored, the monomorphic phase of some polymorphic entities may yet be discovered. More gradual clines within the polymorphic phase have been observed round the coastline of Malaya. In general, gene frequencies tend to be remarkably uniform over long stretches of coastline which presumably indicates that, for the gene(s) in question, the conditions affecting survival value are similarly uniform. By the same token, changes in gene frequency presumably indicate changes in the environment. There is a strong prima facie case that this is so for the major discontinuity between western Clithon from India and Ceylon, and that from the eastern regions. In this instance, surface salinity appears to be one of the factors responsible, and the same parameter may be involved in the changes of incidence in purple spirals. It may be surmised that, in other instances, there are other environmental differentials whose nature remains to be discovered. The relation between selection and adaptation is also discussed, it being maintained that a change in gene frequency brought about by a change in the environment is not, in itself, evidence that the change is adaptive in nature. The incidence of most morphs in Clithon is stable over great distances. This ‘linear stability’ of gene frequencies is evidently the one-dimensional equivalent of the ‘area effects’ in land snails like Cepaea . Only a single entity, ‘black’ (and perhaps ‘giant tongues’) shows irregular fluctuations of gene frequency over short distances and thus seems to be influenced by local littoral conditions.

The observed relation between the Kolmogorov and von Karman constants in the surface boundary layer

In steady, neutrally-stratified flow over uniform terrain, the Kolmogorov constant for the one-dimensional spectrum in the inertial subrange (α1) and the von Karman constant of the logarithmic profile (k) are shown to be related by $$\alpha _1 k^{{4 \mathord{\left/ {\vphantom {4 3}} \right. \kern-\nulldelimiterspace} 3}} = \left[ {\frac{{\sum \phi }}{{0.555}}} \right]\left[ {\frac{{nz}}{{\bar U_z }}} \right]^{{2 \mathord{\left/ {\vphantom {2 3}} \right. \kern-\nulldelimiterspace} 3}} \left[ {\frac{{\ln z_2 /z_1 }}{{\bar U_2 - \bar U_1 }}} \right]^2 \simeq 0.136,$$ , where the numerical value results from field measurements recorded in near-ideal conditions. This experimentally-observed Kolmogorov-von Karman ‘K-von K’ product is close to the value designated by a one-dimensional equivalent of the theoretical relation previously given by Roth (1970). More-over, it is in remarkably close agreement with new values of both constants independently proposed in recent years.

The Technique of Serial Correlation Applied to Continuous Series of Element Concentration Values in Homogeneous Rocks

A technique of serial correlation is considered for chemical data on series of adjacent specimens from homogeneous mineral deposits and a critical independent sampling interval (I-interval) is evaluated. Values taken at a sampling interval larger than the I-interval are independent in a probability sense, whereas mutual specimen influence is appreciable for smaller sampling intervals. I-intervals have been calculated for element concentration values from three examples. The I-intervals for weight percentages Zn, Ti, and in deposits of sphalerite, titaniferous magnetite, and molybdenite are 23 feet, 15 feet, and 0.5-2 feet, respectively. The examples are in the field of mineral deposits which are generally better sampled, but the theory may be applied to element concentration values in other continuous, homogeneous rocks showing random frequency distribution for a specified element. The I-interval is the one-dimensional equivalent of the PRobable-INfluence CE11 (prince), which indicates the sphere of influence of a certain value. The approximate size of the prince should be considered in sampling problems such as choosing specimen sizes and distances between the individual specimens.