Rough Constraints Research Articles

EOF Analysis of Water Level Variations for Microtidal and Mangrove-Covered Frog Creek System, West–Central Florida

Abstract Zhang, J.; Wang, P., and Hughes, J., 2012. EOF analysis of water level variations for microtidal and mangrove-covered Frog Creek system, west-central Florida. At present, little is known about the mechanisms that control water level variations for the Frog Creek system, west–central Florida, which is a mangrove-covered, microtidal, shallow estuary. Although connected with open waters, topographic and roughness constraints can alter expected variability of water levels in this area. Water level variations are especially important for the Frog Creek system, because the increases or decreases in subtidal water level change the present tidal environments. In this paper, 1-year measurements of water levels were examined using the empirical orthogonal function (EOF) method. Water level data from eight stations were first filtered by employing a Lancz6-squared filter because of its ability to eliminate diurnal tidal signals while inducing minimal attenuation in variations with periods of 2 to 3 days, wh...

Marine CSEM of the Scarborough gas field, Part 1: Experimental design and data uncertainty

We describe the planning, processing, and uncertainty analysis for a marine CSEM survey of the Scarborough gas field off the northwest coast of Australia, consisting of 20 transmitter tow lines and 144 deployments positioned along a dense 2D profile and a complex 3D grid. The purpose of this survey was to collect a high-quality data set over a known hydrocarbon prospect and use it to further the development of CSEM as a hydrocarbon mapping tool. Recent improvements in navigation and processing techniques yielded high-quality frequency domain data. Data pseudosections exhibit a significant anomaly that is laterally confined within the known reservoir location. Perturbation analysis of the uncertainties in the transmitter parameters yielded predicted uncertainties in amplitude and phase of just a few percent at close ranges. These uncertainties may, however, be underestimated. We introduce a method for more accurately deriving uncertainties using a line of receivers towed twice in opposite directions. Comparing the residuals for each line yields a Gaussian distribution directly related to the aggregate uncertainty of the transmitter parameters. Constraints on systematic error in the transmitter antenna dip and inline range can be calculated by perturbation analysis. Uncertainties are not equal in amplitude and phase, suggesting that inversion of these data would be better suited in these components rather than in real and imaginary components. One-dimensional inversion showed that the reservoir and a confounding resistive layer above it cannot be separately resolved even when the roughness constraint is modified to allow for jumps in resistivity and prejudices are provided, indicating that this level of detail is beyond the single-site CSEM data. Further, when range-dependent error bars are used, the resolution decreases at a shallower depth than when a fixed-error level is used.

Modeling and Analysis of the Grinding Parameters

Efficient grinding of structural ceramics requires judicious selection of operating parameters to maximize removal rate while controlling surface integrity. Grinding of ceramics is difficult because of its low fracture toughness, making it very sensitive to cracking. In the present work, experiments were carried out to study the effect of wheel parameters such as grain size and grinding parameters like depth of cut and feed rate on the surface roughness and surface damage. The significance of the grinding parameters on the selected responses is evaluated using analysis of variance. Mathematical statistics like “Minitab” is used to analyzed the grinding conditions for maximum material removal, using a multi-objective function model, by imposing surface roughness, surface force and surface damage constraints. The choice of including manufacturer & apposes constraints on the basis of functional requirements of the component for maximizing the production rate is also embedded in the Mathematical statistics. For the verification of present work, the Mathematical statistics results are compared with experimental work.

Cost optimization for the cutting a cobalt chrome refractory material

This paper shows a complete approach to solve a given problem, from the experimentation to the optimization of different cutting parameters. To solve an industrial problem of slotting CoCr29Ni10W7, a Cobalt-based refractory material, we have implemented a design of experiment to determine the effect of cutting parameters on tool life, surface roughness, and cutting forces. After theses trials, an optimization approach has been implemented to find the lowest manufacturing cost while respecting the roughness constraints and cutting force limitation constraints. The optimization approach is based on the Response Surface Method using the Sequential Quadratic programming algorithm and Kriging interpolation for a constrained problem.

Cosmic microwave background bispectrum of tensor passive modes induced from primordial magnetic fields

If the seed magnetic fields exist in the early Universe, tensor components of their anisotropic stresses are not compensated prior to neutrino decoupling and the tensor metric perturbations generated from them survive passively. Consequently, due to the decay of these metric perturbations after recombination, the so-called integrated Sachs-Wolfe effect, the large-scale fluctuations of CMB radiation are significantly boosted. This kind of CMB anisotropy is called the "tensor passive mode." Because these fluctuations deviate largely from the Gaussian statistics due to the quadratic dependence on the strength of the Gaussian magnetic field, not only the power spectrum but also the higher-order correlations have reasonable signals. With these motives, we compute the CMB bispectrum induced by this mode. When the magnetic spectrum obeys a nearly scale-invariant shape, we obtain an estimation of a typical value of the normalized reduced bispectrum as $\ell_1(\ell_1 + 1)\ell_3(\ell_3+1)|b_{\ell_1\ell_2\ell_3}| \sim (130-6) \times 10^{-16} (B_{1 \rm Mpc} / 4.7 {\rm nG})^6$ depending on the energy scale of the magnetic field production from $10^{14}$GeV to $10^3$GeV. Here, $B_{1 {\rm Mpc}}$ is the strength of the primordial magnetic field smoothed on $1 {\rm Mpc}$. From the above estimation and the current observational constraint on the primordial non-Gaussianity, we get a rough constraint on the magnetic field strength as $B_{1 {\rm Mpc}} < 2.6 - 4.4 {\rm nG}$.

Cassini INMS observations of neutral molecules in Saturn's E‐ring

In 2008, the Cassini ion neutral mass spectrometer (INMS) investigation made in situ measurements of neutral species near Saturn's equatorial plane within 0.5 Saturn radii (RS) of the orbit of Enceladus. After removing the large background and modeling to interpret instrumental effects, the data provide rough constraints on the neutral distribution and composition. These data show an azimuthal asymmetry in the neutral densities and provide measurements used to compare to simulations of neutral H2O emitted from Enceladus. Far from Enceladus, the neutral water densities, at a few times 103 molecules/cm3, are near the detection limit of INMS. Near Enceladus, but outside of the plumes and north of the equatorial plane, the INMS detects particles within 5000 km of Enceladus, with the density increasing to approximately 105 molecules/cm3 at the equatorial plane. The observations also show CO2 in the form of its dissociated product, CO. On the basis of the spatial distribution of CO2 counts, the scale height of the neutral cloud above and below the equatorial plane is less than 7000 km. Far from Enceladus, the concentration of CO2 with respect to H2O increases, a consequence of the predicted decline in H2O density. Relatively high counts at 2 amu are infrequently observed. These measurements indicate H2 released during ice‐grain impacts and provide a constraint on the frequency and distribution of small ice grains.

Snow scattering signals in ground‐based passive microwave radiometer measurements

This paper investigates the influence of snow microphysical parameters on the enhancement of ground‐based passive microwave brightness temperature (TB) measurements. In addition to multispectral passive microwave observations between 20 and 150 GHz, a 35 GHz cloud radar and a 2‐D video disdrometer for in situ measurements of snowfall were deployed as part of the “towards an optimal estimation‐based snowfall characterization algorithm” campaign in the winter season of 2008–2009 at an Alpine environment located at 2650 m mean sea level. These observations are combined with nearby radiosonde ascents and surface standard meteorological measurements to reconstruct the atmospheric state (i.e., fields of temperature, humidity, snow, and liquid water contents) and are subsequently used as input for a microwave radiative transfer (RT) model. We investigate the sensitivity of the missing information about snow shape and snow particle size distribution (SSD) on the microwave TB measurements using the disdrometer data as a rough constraint. For an extended case study, we found that TBs at 90 and 150 GHz are significantly enhanced because of scattering of surface radiation at snow crystals and that this enhancement is clearly correlated with the radar derived snow water path (SWP &lt; 0.2 kg m−2). RT simulations highlight the strong influence of the vertical distribution of cloud liquid water (liquid water path LWP &lt; 0.1 kg m−2) on the TB, which in extreme cases, can fully obscure the snow scattering signal. TB variations of the same magnitude can also be caused by typical variations in SSD parameters and particle shape similar to results obtained by space‐borne studies. Ground‐based stations with their infrastructural capabilities in combining active and passive microwave observations have the potential to disentangle the influences of different snow shape, SSD, and SWP in snow retrievals, thus supporting current and future satellite missions.

Position of the Lhasa terrane prior to India-Asia collision derived from palaeomagnetic inclinations of 53 Ma old dykes of the Linzhou Basin: constraints on the age of collision and post-collisional shortening within the Tibetan Plateau

The Lhasa terrane comprises the southern Eurasian margin since at least mid-Cretaceous. Therefore paleomagnetic data from the Lhasa terrane are crucial to reconstruct the pre-collisional southern margin of Eurasia. Previous paleomagnetic data from the Cretaceous Takena Formation provide a rough constraint on the pre-collisional paleolatitudinal position of the southern Eurasian margin. However, Paleogene paleomagnetic data from the Lhasa terrane, which can provide more direct constraints, are very limited. In addition, reliability of the existing data is ambiguous because of a possible later overprint. In our new study 17 sites were drilled from mafic dykes intruded in the T1 unit of the Linzizong Formation of the Linzhou Basin near Lhasa for paleomagnetic studies (Figure 1). The dykes were Ar 40 /Ar 39 dated to c. 53 Ma by Yue and Ding (2006). From ten sites a higher coercivity component demagnetized between 20 and 100 mT could be isolated. Detailed rockmagnetic analyses reveal Ti-rich titanomagnetite as the remanence carrier, which suggests that the rock is not much altered and the remanent magnetization is likely of primary origin. This is supported by a positive fold test. The occurrence of normal and reverse polarity directions within single sites, the subvolcanic character of the dykes, and the within-site scatter, as well as the scatter between site mean directions, indicate that paleosecular variation is recorded within sites. Tilt correction was performed using the bedding of overlying fluvial- lacustrine sediments and tilt angles of ignimbrite columns postdating the dyke emplacement. Bedding-corrected directions give an overall mean direction of D/I = 12.3°/27.2° (α95 = 10.6°, k = 21.7, N = 10) corresponding to a paleolatitude of 13.2° ± 5.8°N at a reference location on the suture zone (20°N/90°E). Comparison with previous Cretaceous data mainly from the Takena Formation yields a stable position of the Lhasa terrane during Cretaceous and Early Eocene. This indicates that no large north-south crustal shortening occurred along the southern Eurasian margin between Late Cretaceous and Early Eocene. The difference between expected paleolatitudes determined from the APWP of Eurasia and observed paleolatitudes reveals relative northward movement of the Lhasa block of ca. 1847±763 km since Early Eocene. This is attributed to indentation of India into Asia and implies a considerable amount of north-south crustal shortening. Two models of “Greater India” were used to determine the extended northern margin of India: Ali and Aitchison (2005) proposed a Greater India based on bathymetric features in the Eastern Indian Ocean and Patzelt and others (1996) determined the paleolatitude of northern India using paleomagnetic investigations on Paleocene sediments of the Zongpu Formation at Gamba and Duela. Intersection of the pre-collisional southern Eurasian margin and the northern margin of India yields a collision age of the Indian and Eurasian continents of c. 5349 Ma. An initial collision within this time range is in accordance with previous studies based on paleomagnetic or geologic data (e.g. Patriat and Achache 1984, Klootwijk and others, 1992, Guillot and others, 2003). A significantly later collision age at the Eocene/Oligocene boundary as proposed by Aitchison and others (2007) is not in agreement with our new and previous paleomagnetic data from the Lhasa Block.

STAR FORMATION HISTORY OF A YOUNG SUPER-STAR CLUSTER IN NGC 4038/39: DIRECT DETECTION OF LOW-MASS PRE-MAIN SEQUENCE STARS

We present an analysis of the near-infrared spectrum of a young massive star cluster in the overlap region of the interacting galaxies NGC 4038/39 using population synthesis models. Our goal is to model the cluster population as well as provide rough constraints on its initial mass function (IMF). The cluster shows signs of youth such as thermal radio emission and strong hydrogen emission lines in the near-infrared. Late-type absorption lines are also present which are indicative of late-type stars in the cluster. The strength and ratio of these absorption lines cannot be reproduced through either late-type pre-main sequence (PMS) stars or red supergiants alone. Thus we interpret the spectrum as a superposition of two star clusters of different ages, which is feasible since the 1" spectrum encompasses a physical region of ~90 pc and radii of super-star clusters are generally measured to be a few parsecs. One cluster is young (<= 3 Myr) and is responsible for part of the late-type absorption features, which are due to PMS stars in the cluster, and the hydrogen emission lines. The second cluster is older (6 Myr - 18 Myr) and is needed to reproduce the overall depth of the late-type absorption features in the spectrum. Both are required to accurately reproduce the near-infrared spectrum of the object. Thus we have directly detected PMS objects in an unresolved super-star cluster for the first time using a combination of population synthesis models and pre-main sequence tracks. This analysis serves as a testbed of our technique to constrain the low-mass IMF in young super-star clusters as well as an exploration of the star formation history of young UC HII regions.

Investigation of optimal machining parameters for turning operation using intelligent techniques

Determination of optimum machining parameters for turning operation has been investigated using non-traditional optimisation techniques and compared the results with Nelder-Mead simplex (NMS) method. The combination minimum production time and cost is considered as the objective function. The optimum machining parameters such cutting speed, feed, depth of cut are determined by simulated annealing algorithm, genetic algorithm, particle swarm optimisation, memetic algorithm and hybrid algorithm. Physical constraints are speed, feed, depth of cut, power limitation, surface roughness, cutting force and temperature constraints.

A multi-objective decision-making model with fuzzy rough coefficients and its application to the inventory problem

In this paper, we concentrate on developing a fuzzy rough multi-objective decision-making model according to uncertainty theory. We present some equivalent models and a traditional algorithm based on an interactive fuzzy satisfying method, which is similar to the interactive fuzzy rough satisfying method, in order to obtain a satisfying solution for the decision maker. In addition, the technique of fuzzy rough simulation is applied to deal with general fuzzy rough objective functions and fuzzy rough constraints which are usually difficult to convert into their equivalents. Furthermore, combined with the techniques of fuzzy rough simulation, a genetic algorithm using the compromise approach is designed for solving a fuzzy rough multi-objective programming problem. Finally, a model is applied to an inventory problem to illustrate the usefulness of the proposed model and algorithm, and then a sensitivity analysis is made.

A QUASI-STATIONARY SOLUTION TO GLIESE 436b's ECCENTRICITY

We investigate the possibility that the large orbital eccentricity of the transiting Neptune-mass planet Gliese 436b (Gl 436b) is maintained in the face of tidal dissipation by a second planet in the system. We find that the currently observed configuration can be understood if Gl 436b and a putative companion have evolved to a quasi-stationary fixed point in which the planets' orbital apses are co-linear and in which secular variations in the orbital eccentricities of the two planets have been almost entirely damped out. In our picture, the two planets are currently experiencing a long period of gradual orbital circularization. Specifically, if Gl 436b has a tidal Q ∼ 300,000, similar to both the Jovian Q and to the upper limit for the Neptunian Q, then this circularization timescale can be of order τ ∼ 8 Gyr given the presence of a favorably situated perturber. We adopt an octopole-order secular theory based on a Legendre expansion in the semimajor axis ratio a1/a2 to delineate well-defined regions of (Pc, Mc, ec) space that can be occupied by a perturbing companion. This description includes the leading-order effects of general relativity, and retains accuracy for perturbing companion planets that have high eccentricity. We incorporate the evolutionary effect of tidal dissipation into our secular model of the system, and solve the resulting initial value problems for a large sample of the allowed configurations. We find a locus of apsidally aligned configurations that are (1) consistent with the currently published radial velocity data, (2) consistent with the current lack of observed transit timing variations (TTVs), (3) subject to rough constraint on dynamical stability, and which (4) have damping timescales consistent with the current multi-Gyr age of the star. We then polish the stationary configurations derived from secular theory with full numerical integrations, and compute the TTVs and radial velocity half-amplitudes induced by the resulting configurations. We present our results in the form of candidate companion planets to Gl 436b. For these candidates, radial velocity half-amplitudes, Kc, are of order 3 m s-1, and the maximum amplitude of orbit-to-orbit TTVs are of order Δt = 1 s to Δt = 5 s. For the particular example case of a perturber with orbital period, Pc = 40 d, mass, Mc = 8.5 M⊕, and eccentricity, ec = 0.58, we confirm our semianalytic calculations with a full numerical three-body integration of the orbital decay that includes tidal damping and spin evolution. Additionally, we discuss the possibility of many-perturber stationary configurations, utilizing modified Laplace–Lagrange secular theory. We then perform a proof-of-concept tidally dissipated numerical integration with three planets, which shows the system approaching a triply circular state.

A class of multiobjective linear programming models with random rough coefficients

In the present paper, we concentrate on dealing with a class of multiobjective programming problems with random rough coefficients. We first discuss how to turn a constrained model with random rough variables into crisp equivalent models. Then an interactive algorithm which is similar to the interactive fuzzy satisfying method is introduced to obtain the decision maker’s satisfying solution. In addition, the technique of random rough simulation is applied to deal with general random rough objective functions and random rough constraints which are usually hard to convert into their crisp equivalents. Furthermore, combined with the techniques of random rough simulation, a genetic algorithm using the compromise approach is designed for solving a random rough multiobjective programming problem. Finally, illustrative examples are given in order to show the application of the proposed models and algorithms.

Two-Dimensional Radio Frequency Tomography

A new formalism for scalar tomographic inversion is developed for two-dimensional radio frequency tomography. A least squares minimization of the difference between predicted and measured data is performed in order to obtain the lossless permittivity distribution. The novelty of the method is twofold. First, a multifrequency near-field two-dimensional scattering forward problem is solved via Richmond's moment method. Second, the tomographic inversion is regularized using a roughness constraint on the model permittivity. The algorithm has been tested with synthetic data. The experimental setup for acquiring the relevant data in a real-world application (viz. in situ testing of lumber quality) is under development. It is anticipated that the algorithm will work equally well on the experimental data. In the tests, the relative lossless permittivity was determined from synthetic scattered multifrequency transverse magnetic data, which had been corrupted by additive Gaussian noise. The method was able to recover the location and magnitude of permittivity anomalies without immersing the target prism in a matching fluid

Yield Property Characterization for Au and TiN Thin Films by Applying Nanoindentation Technique

We tried to apply the nanoindentation technique to yield strength characterization by modifying a previous research. Although the yield strength determining technique developed by Kramer et al. has been successfully demonstrated for large scale indentations on bulky metals, its applicability is still doubtful to nanoscale indentations on thin films with severe roughness, anisotropy, and interfacial constraint. In order to overcome these problems, we combined the nanoindentation technique with a three-dimensional indent visualization technique in this study. Nanoindentation tests were performed for Au and TiN thin films and their corresponding indents were scanned by using an atomic force microscope. From the three-dimensional pile-up morphology, a circular pile-up boundary was measured and input into the yield strength formulation as an effective yielded zone radius. The yield strengths calculated were directly compared with those from the microtensile test.

Geochemical investigation of serpentinized oceanic lithospheric mantle in the Feather River Ophiolite, California: Implications for the recycling rate of water by subduction

The petrology and geochemistry of serpentinized harzburgites within the Feather River Ophiolite in northern California were investigated to constrain the origin of serpentinization. Trace-element systematics indicate that serpentinization was associated almost solely with relatively low temperature hydrothermal addition of seawater and not with the addition of metamorphic fluids associated with subduction or tectonic obduction. Major element systematics show almost negligible disturbance, suggesting low water/rock ratios rather than the very high water/rock ratios characteristic of serpentinization of exhumed mantle at the seafloor such as seen in abyssal peridotites. These observations were taken to indicate that serpentinization occurred by the addition of seawater to ultramafic protoliths while they were structurally within the oceanic lithosphere prior to tectonic accretion. Major and trace element systematics were used with simple melting models and assumptions about the thermal state of the mantle to put rough constraints on the paleo-depths at which the ultramafic protoliths were the last melted. Assuming that these peridotites were formed beneath a passive upwelling system, these paleo-melting depths were assumed to equate with paleo-serpentinization depths. For a model mantle potential temperature of 1350 °C, the paleo-serpentinization depth was estimated to be at least ∼ 40 km based on the minimum melting degree observed in the Feather River Ophiolite peridotites. This depth constraint on serpentinization was then combined with model estimates of the lateral extent of serpentinization assuming that serpentinization is associated with infiltration of water through faults and fractures. If these observations can be generalized, we estimate that recycling rate of serpentine-bound water in subduction zones is roughly one order of magnitude higher than that associated with mineralogically bound water in subducting oceanic crust and sediments. After accounting for serpentine recycling, it is shown that the recycling rate of water via subduction is roughly equal to the global volcanic dewatering rate, suggesting that the water budget of the ocean and Earth's interior may presently be close to steady state.

The k-2Rupture Model Parametric Study: Example of the 1999 Athens Earthquake

We employ a realistic finite-extent “k −2 ” stochastic source model with k-dependent rise time, introduced by Bernard et al. (1996) and extended by Gallovic and Brokesova (2004), to synthesize the strong ground motions in near source distances. For a given magnitude, this rupture model involves a number of free parameters (fault dimensions, slip roughness, maximum rise time, slip velocity function). We study their influence on the peak ground acceleration (PGA) maps (parametric study) for an example of the 1999 Athens earthquake of Mw = 5.9. The observed macroseismic intensities serve us as a rough constraint on the simulated PGA’s to find a set of suitable k −2 models. These

Meter‐scale slopes of candidate MER landing sites from point photoclinometry

Photoclinometry was used to analyze the small‐scale roughness of areas that fall within the proposed Mars Exploration Rover (MER) 2003 landing ellipses. The landing ellipses presented in this study were those in Athabasca Valles, Elysium Planitia, Eos Chasma, Gusev Crater, Isidis Planitia, Melas Chasma, and Meridiani Planum. We were able to constrain surface slopes on length scales comparable to the image resolution (1.5 to 12 m/pixel). The MER 2003 mission has various engineering constraints that each candidate landing ellipse must satisfy. These constraints indicate that the statistical slope values at 5 m baselines are an important criterion. We used our technique to constrain maximum surface slopes across large swaths of each image, and built up slope statistics for the images in each landing ellipse. We are confident that all MER 2003 landing site ellipses in this study, with the exception of the Melas Chasma ellipse, are within the small‐scale roughness constraints. Our results have provided input into the landing hazard assessment process. In addition to evaluating the safety of the landing sites, our mapping of small‐scale roughnesses can also be used to better define and map morphologic units. The morphology of a surface is characterized by the slope distribution and magnitude of slopes. In looking at how slopes are distributed, we can better define landforms and determine the boundaries of morphologic units.

Selection of optimum conditions for maximum material removal rate with surface finish and damage as constraints in SiC grinding

Efficient grinding of structural ceramics requires judicious selection of operating parameters to maximize removal rate while controlling surface integrity. Grinding of silicon carbide is difficult because of its low fracture toughness, making it very sensitive to cracking. In the present work, experiments were carried out to study the effect of wheel parameters; grain size and grain density and grinding parameters; depth of cut and feed on the surface roughness and surface damage. The significance of the grinding parameters on the selected responses was evaluated using analysis of variance. Mathematical models were developed using the experimental data considering only the significant parameters. A genetic algorithm (GA) code has been developed to optimize the grinding conditions for maximum material removal, using a multi-objective function model, by imposing surface roughness and surface damage constraints. The choice of including manufacturer’s constraints on the basis of functional requirements of the component for maximizing the production rate was also embedded in the GA code.

Model-independent constraint on the neutrino mass spectrum from the neutrinoless double beta decay

We present a concise formula to relate the effective mass term of the neutrinoless double beta decay to a single neutrino mass, two Majorana CP-violating phases and four observables of neutrino oscillations for a generic neutrino mass spectrum. If the alleged evidence for the neutrinoless double beta decay is taken into account, one may obtain a rough but model-independent constraint on the absolute scale of neutrino masses -- it is most likely to be in the range between 0.1 eV and 1 eV.