Geometric modeling of geospatial data for visualization-assisted excavation

Underground utility lines being struck by mechanized excavators during construction or maintenance operations is a long standing problem. Besides the disruptions to public services, daily life, and commerce, utility strike accidents lead to injuries, fatalities, and property damages that cause significant financial loss. Utility strikes by excavation occur mainly because of the lack of an effective approach to synergize the geospatial utility locations and the movement of excavation equipment into a real-time, three-dimensional (3D) spatial context that is accessible to excavator operators. A critical aspect of enabling such a knowledge-based excavation approach is the geospatial utility data and its geometric modeling. Inaccurate and/or incomplete utility location information could lead to false instilled confidence and be counterproductive to the excavator operator. This paper addresses the computational details in geometric modeling of geospatial utility data for 3D visualization and proximity monitoring to support knowledge-based excavation. The details of the various stages in the life-cycle of underground utility geospatial data are described, and the inherent limitations that preclude the effective use of the data in downstream engineering applications such as excavation guidance are analyzed. Five key requirements - Interactivity, Information Richness, 3-Dimensionality, Accuracy Characterization, and Extensibility – are identified as necessary for the consumption of geospatial utility data in location-sensitive engineering applications. A visualization framework named IDEAL that meets the outlined requirements is developed and presented in this paper to geometrically represent buried utility geospatial data and the movement of excavation equipment in a 3D emulated environment in real-time.     

Ligand‐Free Copper‐Manganese Spinel Oxide‐Catalyzed Tandem One‐Pot C–H Amidation and N‐Arylation of Benzylamines: A Facile Access to 2‐Arylquinazolin‐4(3H)‐ones

An efficient ligand‐free copper‐manganese (Cu‐Mn) spinel oxide‐catalyzed direct tandem C−H oxygenation and N‐arylation of benzylamines has been developed. The method has been utilized for the synthesis of medicinally important 2‐arylquinazolin‐4(3H)‐ones. Salient features of this method include recyclable catalyst, no ligand, excellent product yields, shorter reaction times and a broad substrate scope.

     

A parallel tracking method for acoustic radiation force impulse imaging

Radiation force-based techniques have been developed by several groups for imaging the mechanical properties of tissue. Acoustic Radiation Force Impulse (ARFI) imaging is one such method that uses commercially available scanners to generate localized radiation forces in tissue. The response of the tissue to the radiation force is determined using conventional B-mode imaging pulses to track micron-scale displacements in tissue. Current research in ARFI imaging is focused on producing real-time images of tissue displacements and related mechanical properties. Obstacles to producing a real-time ARFI imaging modality include data acquisition, processing power, data transfer rates, heating of the transducer, and patient safety concerns. We propose a parallel receive beamforming technique to reduce transducer heating and patient acoustic exposure, and to facilitate data acquisition for real-time ARFI imaging. Custom beam sequencing was used with a commercially available scanner to track tissue displacements with parallel-receive beamforming in tissue-mimicking phantoms. Using simulations, the effects of material properties on parallel tracking are observed. Transducer and tissue heating for parallel tracking are compared to standard ARFI beam sequencing. The effects of tracking beam position and size of the tracked region are also discussed in relation to the size and temporal response of the region of applied force, and the impact on ARFI image contrast and signal-to-noise ratio are quantified.     

Trends in wetting behavior for Ag–CuO braze alloys on Ba0.5Sr0.5Co0.8Fe0.2O(3−δ) at elevated temperatures in air

In the current study, Ag–CuO, a reactive air brazing alloy was evaluated for brazing Ba_0.5Sr_0.5Co_0.8Fe_0.2O_(3?δ) (BSCF). In situ contact angle tests were performed on BSCF using Ag–CuO binary mixtures at 950 and 1000 °C, and the interfacial microstructures were evaluated. Wetting contact angles (θ < 90°) were obtained at short times at 950 °C, and the contact angles remained constant at 1000 °C for 1, 2, and 8 mol% CuO contents. Microstructural analysis revealed the dissolution of copper oxide into the BSCF matrix to form copper–cobalt–oxygen rich dissolution products along the BSCF grain boundaries. The formation of a thick interfacial reaction product layer and ridging at the sessile drop triple point indicate that the reaction kinetics are very rapid and that it will require careful process control to obtain the desired thin but continuous interfacial product layer.     

Characterization of Fe–C–Cr Based Hardfacing Alloys

Hardfacing is one of the adaptable methods that can build up the hard and wear resistant surface layer of different materials on the surface of substrate material. It helps them withstand wear, as well as prevent corrosion and high temperature oxidation. In the present investigation three different types of Fe–C–Cr based hardfacing electrodes with varying chemical compositions were deposited on ASTM A36 steel substrate by using manual metal arc welding (MMAW) process. ASTM A36 steel was selected as a base material after consulting with Pressure and Process Boilers, Saharanpur (India), which is a leading manufacturer of boilers. ASTM A36 steel is mostly used by this company for the production of induced draft fans. MMAW process with direct current constant current type power source was used to deposit the hardfaced layers of uniform quality. Straight polarity was used for MMAW process so that more of the arc heat should be concentrated on the electrode. The hardfaced samples were characterized using various characterization techniques and the results of the same were also outlined in the present investigation.     

Er~(3+)-Yb~(3+)-Na~+:ZnWO_4 phosphors for enhanced visible upconversion and temperature sensing applications

The crystal structure and surface morphology of the Er³⁺/Yb³⁺/Na+:ZnWO₄ phosphors synthesized by solid state reaction method were analyzed by X-ray diffraction(XRD) and field emission scanning electron microscopy(FESEM) analysis.The frequency upconversion(UC) emission study in the developed phosphors was investigated by using 980 nm laser diode excitation.The effect of codoping in the Er³⁺:ZnWO₄ phosphors on the UC emission intensity was studied.The UC emission bands that are exhibited in the blue(490 nm),green(530,552 nm),red(668 nm) and NIR(800 nm) region correspond to the ⁴F_7/2→⁴I_15/2.²H_11/2,⁴S_3/2→⁴I_15/2,⁴F_9/2→⁴I_15/2 and ⁴I9/2→⁴I_15/2 transitions,respectively.The temperature sensing performance of the Er³⁺-Yb³⁺-Na+:ZnWO₄ phosphors was investigated based on the 2 H_11/2→⁴I_15/2 and ⁴S_3/2→⁴I_15/2 thermally coupled transitions of the Er³⁺ions.The photometric study was also carried out for the developed phosphors.     

Rapid geometric modeling for visual simulation using semi-automated reconstruction from single image

This paper presents a novel algorithm that enables the semi-automatic reconstruction of human-made structures (e.g., buildings) into piecewise planar 3D models from a single image. This allows the models to be readily used in virtual or augmented reality visual simulations or for data acquisition in 3D geographic information systems. Contrary to traditional labor-intensive but accurate single view reconstruction (SVR) solutions based purely on geometric constraints, and contrary to recent fully automatic albeit low-accuracy SVR algorithms based on statistical inference, the presented method achieves a compromise between speed and accuracy, leading to less user input and acceptable visual effects. The user input required in the presented approach is primarily a line drawing that represents an outline of the building to be reconstructed. Using this input, the developed method takes advantage of a newly proposed vanishing point (VP) detection algorithm that can simultaneously estimate multiple VPs in an image. With those VPs, the normal direction of planes—which are projected onto the image plane as polygons in the line drawing—can be automatically calculated. Following this step, a linear system similar to the traditional SVR solutions can be used to achieve 3D reconstruction. Experiments that demonstrate the efficacy and visual outcome of the developed method are also described, highlighting the method’s potential use for rapid geometric model building of surrounding structures in visual simulation of engineering processes.