The geology and geochronology of Al Wahbah maar crater, Harrat Kishb, Saudi Arabia

Al Wahbah is a large (∼2.2 km diameter, ∼250 m deep) maar crater in the Harrat Kishb volcanic field in western Saudi Arabia. It cuts Proterozoic basement rocks and two Quaternary basanite lava flows, and is rimmed with an eroded tuff ring of debris from the phreatomagmatic explosion that generated the crater. A scoria cone on the northern wall of the crater was dissected by the explosion and exposes a dolerite plug that was intruded immediately prior to crater formation. The dolerite plug yields a <sup>40</sup>Ar/<sup>39</sup>Ar age of 1.147 ± 0.004 Ma. This is the best possible estimate of the time Al Wahbah crater formed. It is a few tens of thousand years younger than the age of the lower and upper basalt flows, 1.261 ± 0.021 Ma and 1.178 ± 0.007 Ma respectively. A dolerite dyke exposed within the basement in the wall of the crater is dated at 1.886 ± 0.008 Ma. This is the most precise age so far determined for the initiation of basaltic volcanism of Harrat Kishb, and confirms that it is significantly younger than the other post-rift volcanic provinces in the region. This study provides constrains the timing of humid climatic conditions in the region and suggests that the Quaternary basaltic volcanism that stretches the length of the western side of the Arabian peninsula may prove to be useful for establishing palaeoclimatic conditions

Action recognition using Kinematics Posture Feature on 3D skeleton joint locations

Action recognition is a very widely explored research area in computer vision and related fields. We propose Kinematics Posture Feature (KPF) extraction from 3D joint positions based on skeleton data for improving the performance of action recognition. In this approach, we consider the skeleton 3D joints as kinematics sensors. We propose Linear Joint Position Feature (LJPF) and Angular Joint Position Feature (AJPF) based on 3D linear joint positions and angles between bone segments. We then combine these two kinematics features for each video frame for each action to create the KPF feature sets. These feature sets encode the variation of motion in the temporal domain as if each body joint represents kinematics position and orientation sensors. In the next stage, we process the extracted KPF feature descriptor by using a low pass filter, and segment them by using sliding windows with optimized length. This concept resembles the approach of processing kinematics sensor data. From the segmented windows, we compute the Position-based Statistical Feature (PSF). These features consist of temporal domain statistical features (e.g., mean, standard deviation, variance, etc.). These statistical features encode the variation of postures (i.e., joint positions and angles) across the video frames. For performing classification, we explore Support Vector Machine (Linear), RNN, CNNRNN, and ConvRNN model. The proposed PSF feature sets demonstrate prominent performance in both statistical machine learning- and deep learning-based models. For evaluation, we explore five benchmark datasets namely UTKinect-Action3D, Kinect Activity Recognition Dataset (KARD), MSR 3D Action Pairs, Florence 3D, and Office Activity Dataset (OAD). To prevent overfitting, we consider the leave-one-subject-out framework as the experimental setup and perform 10-fold cross-validation. Our approach outperforms several existing methods in these benchmark datasets and achieves very promising classification performance

2-((E)-{[4-(Hy­droxy­meth­yl)phen­yl]imino}­meth­yl)phenol

The title compound, C14H13NO2, adopts the enol–imine tautomeric form, with an intra­molecular O—H⋯N hydrogen bond which generates an S(6) ring motif. The dihedral angle between the aromatic rings is 7.85 (7)°. The crystal structure is stabilized by O—H⋯O, O—H⋯N and C—H⋯O hydrogen bonds, forming a two-dimensional array that stacks along the a axis. In addition, a C—H⋯π inter­action contributes to the stabilization of the crystal packing

Ethyl (Z)-2-(4-chloro­benzyl­idene)-3-oxobutano­ate

The C=C double-bond in the title compound, C13H13ClO3, has a Z configuration. The aliphatic substituents at one end of the double bond, i.e. the CH3CO– and C2H5O2C– groups, are aligned at 82.1 (3)° with respect to each other

Laser polishing of selective laser melted components

The shape complexities of aerospace components are continuously increasing, which encourages industries to refine their manufacturing processes. Among such processes, the selective laser melting (SLM) process is becoming an economical and energy efficient alternative to conventional manufacturing processes. However, dependant on the component shape, the high surface roughness observed with SLM parts can affect the surface integrity and geometric tolerances of the manufactured components. To account for this, laser polishing of SLM components is emerging as a viable process to achieve high-quality surfaces. This report details an investigation carried out to understand the basic fundamentals of continuous wave laser polishing of SLM samples. A numerical model, based on a computational fluid dynamic formulation, was used to assist the understanding of melt pool dynamics, which significantly controls the final surface roughness. The investigation identified the input thermal energy as the key parameter that significantly affect the melt pool convection, and essentially controls the surface quality. Minimum meltpool velocity is essential to achieve wider laser polished track width with good surface finish. Experimental results showed a reduction of surface roughness from 10.2 μm to 2.4 μm after laser polishing with optimised parameters. Strategies to control the surface topology during laser polishing of SLM components are discussed

Convective transport suppression in the scrape-off layer using Ion Cyclotron resonance heating on the ASDEX upgrade Tokamak

Turbulence properties in the scrape-off layer (SOL) in the presence of ion cyclotron frequency heating (ICRH) are compared to instances where it is absent. The discharges are all in a high-confinement mode (H-mode) regime. During ICRH, the SOL plasma density increases whereas turbulence large-scale and convective structures are shown to be suppressed. The probability distribution function is thus recorded to be closer to a Gaussian, and a net decrease in the low-frequency density fluctuations is reflected in the power spectra. Consequently, the level of turbulent fluctuations decreases significantly. Turbulence suppression is also reported during edge localized modes (ELMs) where both the ELMs-induced transport and duration are strongly affected. The increase of neutrals by gas puffing did not alter this behavior. We deduce that ICRH can be used as to suppress convective transport and reduce the ELM's amplitude

Genotoxic and Anatomical Deteriorations Associated with Potentially Toxic Elements Accumulation in Water Hyacinth Grown in Drainage Water Resources

Potentially toxic elements (PTEs)-induced genotoxicity on aquatic plants is still an open question. Herein, a single clone from a population of water hyacinth covering a large distribution area of Nile River (freshwater) was transplanted in two drainage water resources to explore the hazardous effect of PTEs on molecular, biochemical and anatomical characters of plants compared to those grown in freshwater. Inductivity Coupled Plasma (ICP) analysis indicated that PTEs concentrations in water resources were relatively low in most cases. However, the high tendency of water hyacinth to bio-accumulate and bio-magnify PTEs maximized their concentrations in plant samples (roots in particular). A Random Amplified Polymorphic DNA (RAPD) assay showed the genotoxic effects of PTEs on plants grown in drainage water. PTEs accumulation caused substantial alterations in DNA profiles including the presence or absence of certain bands and even the appearance of new bands. Plants grown in drainage water exhibited several mutations on the electrophoretic profiles and banding pattern of total protein, especially proteins isolated from roots. Several anatomical deteriorations were observed on PTEs-stressed plants including reductions in the thickness of epidermis, cortex and endodermis as well as vascular cylinder diameter. The research findings of this investigation may provide some new insights regarding molecular, biochemical and anatomical responses of water hyacinth grown in drainage water resources.</jats:p

Treating the Impacts of Connecting HVDC Link Converters with AC Power System Using Real-Time Active Power Quality Unit

The High Voltage Direct Current (HVDC) systems have been applied worldwide, due to important roles, technical benefits, and high efficiency. Usually, the HVDC network is a joining link between two separate and different technical properties of HVAC systems, which enhances its use. The joinpoint system that used to connect HVDC and HVAC links is a controlled converter circuit. Despite the importance of use and the significant benefits of the HVDC link, there are negative effects on the power quality of the electrical power of both systems connected on both ends of the HVDC network. The low quality of electric power has been addressed by known methods, whether traditional or modern. But the improvement is usually made with the assumption of load conditions and the need for the system to synthesize it. This research presents an innovative method based on real-time control strategy. This is performed by proposing dSPACE for controlling the Active Power Quality Unit (APQU). The proposed control strategy of the APQU includes a Modified Harmonics Pulse Width Modulation (MHPWM) algorithm in order to mitigate the line current THD and improve the effective power factor of the AC converter sides. The MHPWM is applicable for different nonlinear loads and can be implemented with APQU based on different topologies of H-bridge voltage source inverter. Simulation and practical results have been presented in this paper. The Experimental results are done based on real-time laboratory tests using dSPACE DS1103 board as a controller circuit. The presented results, under different operating loading conditions, show that the APQU provides almost unity power factor and significantly improving THD of the AC supply currents at both sides of the HVDC link controlled converters

EXPERIMENTAL STUDY OF HYBRID LIQUID DESICCANT BASED VAPOR COMPRESSION COOLING SYSTEM

In the kingdom of Saudi Arabia, a vast amount of energy is used for air-conditioning and this paper describes a new approach to air conditioning. In the proposed hybrid cooling system, liquid desiccant is used to remove the latent load and the conventional vapor-compression system is used to provide sensible cooling only. In this experimental study, calcium chloride solution is used as the desiccant to dehumidify the air. Gauze-type structured packing towers are used for the dehumidification of air and also for regeneration of the weak desiccant. The designed packed bed dehumidifier and the regenerator are combined with a 5-ton capacity vapor compression system along with the heat recovery units. This paper presents results from a detailed experimental investigation of the heat and mass transfer in a structured packing dehumidifier and regenerator under a variety of operating conditions. In the present study, for the sake of comparison between hybrid and conventional cooling systems, the COP for the cooling system is defined as the heat removed from the space to be cooled divided by energy input for the cooling system. Three different modes of regeneration are considered for the hybrid cooling system and the COP values are compared with conventional vapor compression system. Results show that the ratio of the outlet-to-inlet absolute humidity reaches a steady state value of about 0.6 and the temperature of air decreased from 48 to 38o C in the dehumidifier of the hybrid system. Moreover, it is found that hybrid cooling system provides higher COP compared with conventional system