The Microstructure and Property of a Titanium-Carbon Steel Clad Plate Prepared Using Explosive Welding

The microstructure and properties of pure titanium (Ti)-carbon steel clad plate prepared using explosive welding were characterized. The bonding of the welding interface was inspected using C-scanning imaging technique. The microstructure and composition of the clad were characterized with optical microscopy and scanning electron microscopy. Mechanical and corrosion properties of the clad plate were investigated using tensile test, shearing test, and potentiodynamic polarization measurement. The results show that the pure titanium and carbon steel plate are joined successfully without visible defects. The interface wave is uniform. SEM observation and EDS analyses show that some melt blocks distribute at the interface waves vortices. Hardness testes results show that after heat treating, the hardness values in the titanium layer of the clad plate are similar to the original titanium plate, whereas the values at carbon steel layer increase from the interface to 300 μm away. Tensile and shearing test results indicate that the mechanical properties of the clad meet the requirements of ASTM B898 standard. Corrosion test shows that the Ecorr of the clad plate is more positive, and icorr is 1 order of magnitude lower compared to carbon steel material, suggesting that the corrosion resistance of clad plate is better than that of carbon steel material. These results suggest that the clad plate has good bonding quality and properties to meet the processing requirement and can be safely applicable in the petrochemical field.

Reduced order model approach for imaging with waves

We introduce a novel, computationally inexpensive approach for imaging with an active array of sensors, which probe an unknown medium with a pulse and measure the resulting waves. The imaging function uses a data driven estimate of the “internal wave” originating from the vicinity of the imaging point and propagating to the sensors through the unknown medium. We explain how this estimate can be obtained using a reduced order model (ROM) for the wave propagation. We analyze the imaging function, connect it to the time reversal process and describe how its resolution depends on the aperture of the array, the bandwidth of the probing pulse and the medium through which the waves propagate. We also show how the internal wave can be used for selective focusing of waves at points in the imaging region. This can be implemented experimentally and can be used for pixel scanning imaging. We assess the performance of the imaging methods with numerical simulations and compare them to the conventional reverse-time migration method and the “backprojection” method introduced recently as an application of the same ROM.

IMAGING OF INTRACRANIAL SPACE OCCUPYING LESIONS

Introduction: With advanced MRI techniques such as perfusion, diffusion, and spectroscopy, it is now possible to differentiate between various intracranial lesions. Materials and Methods: This prospective cohort study was conducted on 50 patients referred by various clinical departments with clinical suspicion of intracranial space occupying lesions, evaluated by computed tomography & magnetic resonance imaging. Result: Solitary lesions were present in 35 patients (70%) & multiple lesions in 15 patients (30%). 68.00% lesions were Supratentorial & 32.00% infratentorial in location. Most common supratentorial location in adults was frontal lobe 40% followed by parietal lobe 30%. Most common supratentorial locations in children were frontal lobe. Infratentorially, cerebellum & posterior fossa were found to be most common location in adults & children respectively. Supratentorial lesions were most common both in adults & children. 60% lesions were intraaxial & 40 % extra axial in location. In adults, intraaxial lesions were more common than in children. Conclusion: Intracranial space occupying lesions comprise of a diverse group of lesions. With the introduction of CT & MRI scanning, imaging of lesions has acquired a new dimension whereby excellent anatomical detail in axial, sagittal & coronal planes as well as lesion characterization has become possible. Key words: Brain, CT, MRIs

Application of Micro-resistivity Scanning Imaging Logging Data in Reservoir Thickness Division

Reservoir parameter interpretation is one of the main contents of reservoir description, which affects the whole process of oilfield development. According to the characteristics of micro-resistivity scanning imaging logging, which can directly reflect the changes of lithology and physical properties of reservoirs, this paper compares the thickness and interbed division of reservoirs with conventional logging data, this paper finds out the shortcomings of the conventional logging data in the interpretation of thickness and the division of interlayers, and combines the core analysis data to examine the differences in the correlation on the coring wells, and obtains good results, it has laid the foundation for the establishment of new interpretation procedure.

Determining the Height of Water-Flowing Fractured Zone in Bedrock-Soil Layer in a Jurassic Coalfield in Northern Shaanxi, China

The height of the water-flowing fractured zone is the most important technical parameter for water prevention and control in a coal mine. Due to the numerous factors affecting the water-flowing fractured zone, it is difficult to accurately identify the zone. Currently, no effective way exists for determination of the water-flowing fractured zone in a soil layer. To accurately determine the development law of the water-flowing fractured zone in the bedrock-soil layer of a Jurassic coalfield in northern Shaanxi, China, we conducted a comprehensive study using microresistivity scanning imaging technology, apparent density logging, long-range gamma logging, observation on drilling flushing fluid consumption, physical simulation, and numerical simulation. The following results were obtained: (1) The ratio of the height of the water-flowing fractured zone to the mining height was 28.3–28.5, which was obtained by microresistivity scanning imaging technology, whereas the ratio of the height of the water-flowing fractured zone to the mining height was 28.1–29.1, determined by apparent density logging, long-range gamma logging, physical simulation, and numerical simulation. The microresistivity scanning imaging results were consistent with those obtained by other methods. (2) Based on the thickness of the soil layer and the bedrock, the height model of the water-flowing fracture zone was divided into four regions, that is, the thick bedrock-thick soil layer region, thick bedrock-thin soil layer region, thin bedrock-thin soil layer region, and thin bedrock-thick soil layer region. A mathematical model describing the difference between the thickness of the water-flowing fractured zone and the bedrock and the thickness of the soil under the condition of bedrock-soil was established. (3) We conclude that microresistivity scanning imaging technology can accurately detect the height of the water-flowing fractured zone in a soil layer, and the apparent density logging and long-range gamma logging can precisely detect the height of the water-flowing fractured zone in bedrock. This is a new comprehensive method for research on the height of the water-flowing fractured zone that can provide a reliable basis for water prevention and control in mines.

Recent Patents on Concrete Pavers of Coalmines

Background: Concrete pavers are self-propelled units used in concrete pavement construction that have of paving, vibrating, and leveling functions. The existing concrete pavers have a large size, making it difficult for them to enter underground roadways, and it is difficult to adjust the paving equipment in real time when the width of the underground roadway is deformed. Objective: To realize intelligent concrete paving in coal mine roadways, based on the analysis of recent concrete paver patents, this paper proposes an intelligent virtual paving system based on 3D infrared scanning imaging. Method: The intelligent virtual paving system, which uses multiple groups of 3D infrared scanners and signal processing systems, can collect and analyze 3D images in the roadway and perform virtual paving in the computer. This system can obtain the required parameters of roadway paving, such as the feeding amount, driving speed, limiter height, and width of the synovium, as well as give the initial paving parameters. Results: In the actual paving process, through virtual paving parameters, the feeding amount and accelerator can be regulated in real time, and the difference between the actual paving and virtual paving can be judged to change the paving width in real time. Conclusion: Intelligent virtual paver systems have a guiding significance for the improvement of existing paver systems.

In vivo Estimation of Breast Cancer Tissue Volume in Subcutaneous Xenotransplantation Mouse Models by Using a High-Sensitivity Fiber-Based Terahertz Scanning Imaging System

Absorption contrast between the terahertz (THz) frequency range of fatty and cancer tissues allows cancer diagnosis by THz imaging. We successfully demonstrated the ability of THz imaging to measure small breast cancer volume in the subcutaneous xenotransplantation mouse models even without external comparison. We estimated the volume detection limitation of the fiber-based THz scanning imaging system using a highly sensitive cryogenic-temperature-operated Schottky diode detector to be smaller than 1 mm3, thus showing the potential application of this technique in preliminary early cancer diagnosis.