Miracle-dz/UniFAR-FTUs huggingface dataset:
A compatible finite element multi‐material ALE hydrodynamics algorithm

The main ideas of compatible Lagrangian hydrodynamics were originally developed in the form of a finite volume scheme by Caramana et al. at LANL. A new compatible finite element Lagrangian hydrodynamics method has been developed and implemented in a 2D arbitrary Lagrangian Eulerian (ALE) code CORVUS. The new finite element method was developed in preference to the published finite volume schemes in order to see if the fundamental principles of compatible hydro could be translated across to other numerical methods in use in hydrocodes and to facilitate a more direct comparison of the performance of the compatible hydro scheme with the existing finite element scheme in CORVUS. The new finite element scheme provides total energy conservation to round off for the Lagrangian step. The edge artificial viscosities and sub‐zonal pressures that have been introduced through the framework of the compatible hydro scheme provide further improvements in terms of accuracy and robustness for Lagrangian calculations. The details of the compatible finite element Lagrangian scheme and the extensions required to the scheme to allow it to be applied as the Lagrangian step of a multi‐material ALE code are discussed. Test problems will be presented to demonstrate some of the benefits and the performance of the new method for hydrocode applications. © British Crown Copyright 2007/MOD. Reproduced with permission. Published by John Wiley & Sons, Ltd.
Observations of interstellar gas towards ω Centauri and the Carina-Sagittarius spiral arm

Interstellar Na D and K I line spectra are reported for three stars which lie within 5° of the ω Cen cluster. These new data have enabled us to complete the identification of the absorption components which are observed in the gas foreground to this cluster. In particular, we discuss a component at velocity v lsr ≃−15 km s −1 which is produced by gas beyond ≃1 kpc and at a distance ≥175 pc above the Galactic plane. We suggest that this feature originates in the gas of the Carina spiral arm. Weaker components having negative peculiar velocities appear to lie beyond the bulk of the −15 km s −1 gas. A comparison of these new observations with similar studies made towards M4 and M22 provides a further indication of the complex structure of the gas over part of the Carina-Sagittarius arm region
Nanolithography with an atomic force microscope by means of vector-scan controlled dynamic plowing

We present a nanolithography technique based on an atomic force microscope. A thin resist layer on the sample surface is plastically indented by a vibrating tip. Controlling of the vibration amplitude and tip movement enables one to plow a narrow furrow along line segments of arbitrary length and direction. Different line segments which form a complex pattern can be plowed at a scan speed up to 5 μm/s. The geometric distortion of the resist pattern is less than 50 nm, where at scan speed in excess of 1 μm/s an interrupt of at least 10 ms is necessary between the line segments. The minimum offset error in positioning a pattern with respect to existing features is less than 4% of the scanning field. The patterns are transferred into SiO2, Si, GaAs, Ti, and Au by wet-chemical etching. Minimum linewidth is 25 nm in 1.5 nm oxide layers, 75 nm in 10 nm Ti film and 40 nm in 10 nm Au. On semiconductor surfaces smooth and perfectly shaped V grooves of 55 nm width are obtained.
Development of a scanning probe microscope compact sensor head featuring a diamond probe mounted on a quartz tuning fork

The development of a compact scanning probe microscope sensor head, designed to mount around a standard microscope objective, is described. The instrument features a quartz tuning fork with an innovative diamond probe. This configuration has a number of key advantages: (i) the displacement of the probe relative to the sample surface is self-sensing, (ii) the diamond tip is robust and (iii) it is designed to accommodate future near-field optical applications. A custom current-to-voltage amplification circuit was conceived to compensate for the inherent capacitance of the quartz tuning fork. A mechanical design has been realized to allow positioning of the probe relative to the microscope objective and the swift exchange of quartz tuning fork sensors. Additionally, the design permits rotation of the sensor so that its orientation with respect to the sample may be changed. To demonstrate the feasibility and resolution of the system, a semi-insulating GaAs wafer has been imaged to reveal the presence of InAs quantum dots (QDs). The QDs can be seen clearly in the image presented here, with their height profiled to be typically 6 nm. Cross-sectional analysis of the raw data gives a background RMS value of 0.6 nm for a profile 2 µm in length.
Where are the X-ray quasi-periodic oscillations in active galaxies?

In this paper, we address the question of whether existing X-ray observations of Seyfert galaxies are sufficiently sensitive to detect quasi-periodic oscillations (QPOs) similar to those observed in the X-ray variations of Galactic black holes (GBHs). We use data from XMM‐Newton and simulated data based on the best Rossi X-ray Timing Explorer (RXTE) long-term monitoring light curves to show that if X-ray QPOs are present in Seyfert X-ray light curves ‐ with similar shapes and strengths to those observed in GBHs, but at lower frequencies commensurate with their larger black hole masses ‐ they would be exceedingly difficult to detect. Our results offer a simple explanation for the present lack of QPO detections in Seyferts. We discuss the improvements in telescope size and monitoring patterns needed to make QPO detections feasible. The most efficient type of future observatory for searching for X-ray QPOs in active Galactic nuclei (AGN) is an X-ray All-Sky Monitor (ASM). A sufficiently sensitive ASM would be ideally suited to detect low-frequency QPOs in nearby AGN. The detection of AGN QPOs would strengthen the AGN‐GBH connection, and could serve as powerful diagnostics of the black hole mass and the structure of the X-ray emitting region in AGN. Ke yw ords: galaxies: active ‐ galaxies: Seyfert ‐ X-ray: galaxies.
Optimal band selection from hyperspectral data for Lantana camara discrimination

The primary objective of this research was to determine the optimal hyperspectral wavelengths based on spectroscopy data over the spectral range of 450–2500 nm for the detection of the invasive species Lantana camara L. (lantana) from seven of its co-occurring species. A procedure based on statistical analysis of the reflectance and the first derivative reflectance (FDR) identified 86 and 18 bands, respectively, where lantana significantly differed from its co-occurring species. The effectiveness of the identified optimal bands was then evaluated using Hyperion imagery. The original Hyperion image with 155 bands gave an overall accuracy of 80% compared to 77% and 76% from the 86- and 18-band spectral subsets, respectively. A pairwise comparison of the three error matrices showed no significant difference in the accuracy achieved. The FDR analysis combined with the statistical analysis proved to be a useful procedure for data reduction by refining the discrimination to fewer optimal bands for lantana detection with no adverse impact on classification accuracy.
From ensemble forecasts to predictive distribution functions

The translation of an ensemble of model runs into a probability distribution is a common task in model-based prediction. Common methods for such ensemble interpretations proceed as if verification and ensemble were draws from the same underlying distribution, an assumption not viable for most, if any, real world ensembles. An alternative is to consider an ensemble as merely a source of information rather than the possible scenarios of reality. This approach, which looks for maps between ensembles and probabilistic distributions, is investigated and extended. Common methods are revisited, and an improvement to standard kernel dressing, called ‘affine kernel dressing’ (AKD), is introduced. AKD assumes an affine mapping between ensemble and verification, typically not acting on individual ensemble members but on the entire ensemble as a whole, the parameters of this mapping are determined in parallel with the other dressing parameters, including a weight assigned to the unconditioned (climatological) distribution. These amendments to standard kernel dressing, albeit simple, can improve performance significantly and are shown to be appropriate for both overdispersive and underdispersive ensembles, unlike standard kernel dressing which exacerbates over dispersion. Studies are presented using operational numerical weather predictions for two locations and data from the Lorenz63 system, demonstrating both effectiveness given operational constraints and statistical significance given a large sample.
The Motion of High-Reynolds-Number Bubbles in Inhomogeneous Flows

▪ Abstract Predicting the motion of bubbles in dispersed flows is a key problem in fluid mechanics that has a bearing on a wide range of applications from oceanography to chemical engineering. In this review we synthesize the recent progress made in describing bubble motion in inhomogeneous flow. A trident approach consisting of experimental, analytical, and numerical work has given a clearer description of the hydrodynamic forces experienced by isolated bubbles moving either in inviscid flows or in slightly viscous laminar flows. A significant part of the paper is devoted to a discussion of drag, added-mass force, and shear-induced lift experienced by spheroidal bubbles moving in inertially dominated, time-dependent, rotational, nonuniform flows. The important influence of surfactants and shape distortion on bubble motion in a quiescent liquid is highlighted. Examples of bubble motion in inhomogeneous flows combining several of the effects mentioned above are discussed.
Events as a Basis for Workflow Scheduling

This paper evaluates using event-based scheduling as a basis for dynamic workflow management. To do this, the WorkflowRunner is introduced as a tool for conducting event driven scheduling in a robust manner. It is evaluated in comparison to Slurm and the WorkflowRunner is found to schedule analysis ~2.5x quicker, in the majority of use cases. An example workflow is also presented, demonstrating how this style of scheduling allows for complete modification of the workflow structure at runtime, something very difficult to achieve in traditional workflow management systems. These developments are expected to be of particular use to dynamic scheduling systems, as well as for distributed, or heterogeneous systems such as those looking to accommodate human-in-the-loop interactions.
AI supported Multi-Functional Gripping System for Dexterous Manipulation Tasks

Dexterous mobile manipulators that are capable of performing a wide array of tasks are essential for unstructured human-centered environments. Especially in rescue scenarios where time and resources are limited, a gripping system should be as versatile but at the same time as efficient as possible. In addition, situational awareness in accidents and impaired visibility is essential for safely performing missions or automating behaviors, and thus supporting operators. The main contribution of this work is a multi-functional gripping system with technologies and methods for manipulation in rescue and recovery operations as well as for handling hazardous materials. The gripping system is supplemented by an RGB and thermal camera and object detection algorithms, which run in real-time on an embedded device for robust recognition in harsh and dynamic environments. The proposed multi-functional gripping system has been thoroughly evaluated and tested in laboratory experiments and real field facilities.
An Optimal Control Approach for Switched Nonlinear Systems Based on Selfish Herd Optimization Algorithm

This paper addresses the optimal control problem of switched nonlinear systems. Indeed, a new mechanistic algorithm called Selfish Herd Optimization (SHO) is suggested. The proposed approach consists of minimizing a defined performance criterion that depends on the optimal switching instants to be found. Finally, the effectiveness of the proposed approach is illustrated through a switched hydraulic two-tank nonlinear system.
Multi-Layer Efficient Data Classification Methods for Enterprise Business Applications

The efficient maintenance and classification of huge amounts of data is a big challenge for the websites which provide services for online businesses. Many of the websites provide multiple services for the customer. In the present work, we have compared various machine learning-based classification methods for the efficient distribution of data. To effectively categorize the data, the Enterprise Interface (El) layer is suggested between the application layer and the physical layer. Methods based on global and local clustering are proposed for the effective distribution of the data in the El layer. For the effective classification of the merchandise as per the various client classes, we have collected four parameters/features from the mall’s customers. We have utilized the K-Means clustering approach to efficiently divide classes (Global Clustering). Additionally, we have examined seven categories for the proper group selection and prediction of recently arrived customers. The performance comparison makes use of Naive Bayesian, Logistic, Decision Tree, Random Forest, Support Vector Machine (SVM), Kernel-SVM, and K-Nearest Neighbor algorithms. The results show that Naive Bayesian and Random Forest Classification approaches outperform other classification techniques. The results also show that the proposed method is better than the existing cluster cum classification method.
Morphology of the magnetic field near Titan: Hybrid model study of the Cassini T9 flyby

We study the deformation and morphology of the magnetic field near Titan by a three‐dimensional numerical quasi‐neutral hybrid model (HYB‐Titan). We analyze two runs, one in which the sub‐rotating plasma consists of oxygen (O+) ions and protons (H+) and another with only protons. We find that both cases result in the generation of Alfvén wing‐like flux tubes. In comparison with the proton‐only case, the direction and magnitude of the magnetic field in the oxygen‐rich flow case are in better agreement with Cassini magnetic field observations during its Titan T9 flyby on Dec. 26, 2006, suggesting that the sub‐rotating plasma contained heavy ions. The oxygen‐rich run also supports the hypotheses that (1) the sub‐rotating flow direction was offset by ∼30°–40° from the ideal rotating flow direction and that (2) the spacecraft was magnetically connected to the sunlit side of near‐Titan space in the tail when it approached Titan on the T9 flyby.
A Deep Learning Model for MOOC Dropout Prediction Using Learner's Course-relevant Activities

Today, Open Massive Online Courses (MOOCs) have become very popular learning platforms with millions of participants. MOOCs provide a flexible distance-learning style courses usually delivered by top international universities. However, despite all benefits and features of MOOCs, these platforms have been heavily criticized due to students' high dropout rate. This have become a phenomenon on MOOCs, where users may enroll in a course but most of these users will dropout the course somewhere before the end. This has triggered the need for a development of a reliable and efficient dropout prediction model that can address this problem and maintain an encouraging learning activity. In this research, we present a deep leaning dropout predictor model to address this classification problem. By observing learner's early course activities and extensive feature engineering, we tried to predict the likelihood of student MOOCs dropout by using deep learning artificial neural networks (ANNs). Through selecting the best parameter values and using validation approach, our model was able to achieve 91% in terms of precision and 90% in terms of accuracy which are better than existing studies. Our obtained results are compared and benchmarked against the existing state of the art literature that addresses the same problem.
On the linear stability of compressible plane Couette flow

The linear stability of compressible plane Couette flow is investigated. The appropriate basic velocity and temperature distributions are perturbed by a small-amplitude normal-mode disturbance. The full small-amplitude disturbance equations are solved numerically at finite Reynolds numbers, and the inviscid limit of these equations is then investigated in some detail. It is found that instabilities can occur, although the corresponding growth rates are often quite small; the stability characteristics of the flow are quite different from unbounded flows. The effects of viscosity are also calculated, asymptotically, and shown to have a stabilizing role in all the cases investigated. Exceptional regimes to the problem occur when the wave speed of the disturbances approaches the velocity of either of the walls, and these regimes are also analysed in some detail. Finally, the effect of imposing radiation-type boundary conditions on the upper (moving) wall (in place of impermeability) is investigated, and shown to yield results common to both bounded and unbounded flows.
Decreasing Trend in Rainfall over Indochina during the Late Summer Monsoon : Impact of Tropical Cyclones

We examined the decreasing trend in rainfall during the late summer monsoon season (September) in Thailand from 1951 to 2000 and associated changes in tropical cyclone (TC) activity. Thailand receives significant rainfall from May to October and experiences two rainy peaks in late May to early June and in September. A previous study reported a decreasing trend in September rainfall in Thailand and, based on a regional climate model, suggested that the trend was associated with local deforestation. However, the long-term trend may also be affected by changes in large-scale circulation. Thus, the purpose of this study was to investigate changes in large-scale circulation associated with the decreasing rainfall trend.Westward-propagating TCs from the South China Sea and the western North Pacific brought most of the rainfall over Thailand in September. TCs include tropical depressions, tropical storms, severe tropical storms, typhoons, and residual lows. 70% of the rainfall amount in September was estimated to be associated with TCs.The 50-year time-series of September rainfall over Thailand showed a significant decreasing trend. TC activity defined by 700-hPa relative vorticity, showed a weakening trend over the Indochina Peninsula. TC tracks also suggested the weakening of TC activity over this area. The long-term trend in rainfall during the late summer monsoon season was closely associated with changes in TC activity over the Indochina Peninsula; these changes were likely caused by changes in the major course of TCs. Concurrent with the changes in TC tracks, there was a change in the TC steering current around the Philippines archipelago and Taiwan. This led to the TC activity over the Indochina Peninsula being inactive, probably resulting in the long-term decrease in rainfall over Thailand.
Point interpolation method based on local residual formulation using radial basis functions

A local radial point interpolation method (LRPIM) based on local residual formulation is presented and applied to solid mechanics in this paper. In LRPIM, the trial function is constructed by the radial point interpolation method (PIM) and establishes discrete equations through a local residual formulation, which can be carried out nodes by nodes. Therefore, element connectivity for trial function and background mesh for integration is not necessary. Radial PIM is used for interpolation so that singularity in polynomial PIM may be avoided. Essential boundary conditions can be imposed by a straightforward and effective manner due to its Delta properties. Moreover, the approximation quality of the radial PIM is evaluated by the surface fitting of given functions. Numerical performance for this LRPIM method is further studied through several numerical examples of solid mechanics.
A Semiparametric Maximum Likelihood Estimator

A maximum likelihood estimator for models containing nuisance parameters is proposed. The estimator is shown to be asymptotically normal and attain the semiparametric efficiency bounds for a number of important econometric models. The idea is to find a parametric model that passes through the true model. The score for the parametric model is then estimated nonparametrically and the estimator is obtained by setting the estimated score to zero.
Stellar Nucleosynthesis and Chemical Evolution of Galaxies

We present the basic theory of nuclear reactions in stars and sketch the general rules of stellar evolution. Then we shortly review the subject of supernova explosions both by core collapse in massive stars (type II) and carbon-deflagration in binary systems when one of the components is a White Dwarf accreting mass from the companion (type Ia). We also present elementary notions of s - and r -process nucleo-synthesis. Finally, we shortly review the topic of galactic chemical evolution and highlight some simple solutions aimed at understanding the main observational data on abundances and abundance ratios.
Global postseismic deformation in a stratified viscoelastic earth: effects on Chandler wobble excitation.

The principal purpose of this paper is to examine whether movement of matter in a stratified viscoelastic earth can enhance the excitation of the Chandler wobble. We have constructed analytically a two-layer model consisting of an elastic lithosphere overlying a Maxwell viscoelastic mantle in order to calculate explicitly the temporal evolution of the inertia tensor from earthquake faulting. It is found that the ability of the viscoelastic flows to produce an additional increment of the inertia tensor depends critically on R, the ratio of the inner radius to the outer radius. Only for R ≳ 0.7 is there a substantial increase. For the earth (R ≃ 0.98) an amplification of between four and six is obtained from the models considered. However, the time scales over which this enhancement of the moment of inertia takes place is about 10 Maxwell times, thus making this model unlikely to excite the Chandler wobble for values of the mantle viscosity derived from postglacial uplifts. This phenomenon of strain amplification occurs by virtue of ‘transient membrane mechanics,’ as the ratio between the horizontal wavelength of the deformation field is large compared with the elastic shell. By means of a similarity argument we have found that for angular orders less than 40 to 45 ‘transient membrane mechanics’ can be important in global postseismic deformation in the earth. This mode of transient deformation arises from the three-dimensional nature of the problem and hence cannot be modeled with conventional flat earth models.