Vibration Signature of Roller Bearing’s Faults

Centrifugal pumps are widely used in many industrial applications. Defective pumps cause higher rate of energy loss with related overall performance degradation. Mechanical components fail due to decrease in pump’s strength or an increase in the force acting on it. Rolling bearings are one of the major components of the centrifugal pumps. Bearings are critical mechanical components in industrial machines. Bearing failure is often attributed to be one of the major causes of breakdown. Early detection of undesired conditions during the operation of the centrifugal pump has become very important in order to avoid consequential damages. Early detection is also vital for increasing availability and reliability. Automated health monitoring can reduce the outage time and repair costs. Using vibration analysis technique to monitor and evaluate the health of the machines has become an important technique in this field. In this research, we studied the vibration signatures of healthy and faulty conditions of the bearings of a pumping system. The pumping system consists of centrifugal pump and electrical motor. The vibration signatures analyze the bearing status with respect to the normal operation. The paper shows how to identify if there is a problem in the outer race of the Bearing Pass Frequency Outer Race (BPFO)

Investigation of in-plane moment connections of I-beams to square concrete-filled steel tube columns under gravity loads

AbstractThis paper focuses on experimental and analytical behavior of the ultimate moment of the connections of steel I-beams to square concrete-filled steel tube columns. External stiffeners around the columns are used at the beam flange levels. Five specimens are tested monotonically. The test parameters are the column stiffener dimensions and filling the steel tube column with concrete. Two types of failure modes are observed; beam flange failure and stiffener failure. The experimental results show that the ultimate moment of the connection is increased by increasing stiffener’s dimensions and filling the steel tube column with concrete. ANSYS finite element program is used to simulate the behavior, taking into account both geometric and material nonlinearities. Analytical results that are in fair agreement with the experimental ones are then used to discuss the influence of the main geometric parameters on the connection behavior. The parameters are the stiffener and column dimensions as well as filling the steel tube column with concrete. Different square column cross sections are chosen to cover the three classes of section classifications according to Egyptian code of practice, which are: compact, non compact or slender. The increase in the ultimate moment of the connections is based upon both column cross sections’ compactness and stiffener dimensions while the maximum advantages occur with slender columns

On the Fractography of Impact-Tested Samples of Al-Si Alloys for Automotive Alloys

Castings were prepared from both industrial and experimental 319.2, B319.2 and A356.2 alloy melts, containing Fe levels of 0.2–1.0 wt%. Stontium-modified (∼200 ppm) melts were also prepared for each alloy/Fe level. Impact testing of heat-treated samples was carried out using an instrumented Charpy impact testing machine. At low Fe levels and high cooling rates (0.4% Fe, dendrite arm spacing (DAS) of 23 μm), crack initiation and propagation in unmodified 319 alloys occur through the cleavage of β-Al5FeSi platelets (rather than by their decohesion from the matrix). The morphology of the platelets (individual or branched) is important in determining the direction of crack propagation. Cracks also propagate through the fracture of undissolved CuAl2 or other Cu intermetallics, as well as through fragmented Si particles. In Sr-modified 319 alloys, cracks are mostly initiated by the fragmentation or cleavage of perforated β-phase platelets, in addition to that of coarse Si particles and undissolved Cu-intermetallics. In A356.2 alloys, cracks initiate mainly through the fracture of Si particles or their debonding from the Al matrix, while crack propagation occurs through the coalescence of fractured Si particles, except when β-Al5FeSi intermetallics are present, in which case the latter takes precedence. In the Sr-modified case, cracks propagate through the linkage of fractured/debonded Si particles, as well as fragmented β-iron intermetallics. In samples exhibiting low-impact energies, crack initiation and propagation occur mainly through cleavage of the β-iron intermetallics

Ion beam and discharge characteristics of cold cathode ion source

24-30In this work, some developments in the acceleration system of cold cathode ion source have been constructed to produce broad beam to be used in different industrial applications. An electrostatic probe with electrical circuit is constructed for study the extracted ion beam distribution. Broad beam 25 mm with ion current in the range of 1 mA is extracted from the constructed extraction system. The obtained optimum distance between the extraction grid and acceleration grid is 3 mm. The characteristics are measured to investigate the ion beam current Ib as a function of different parameters (discharge voltage Vd, gas pressure P, magnetic field intensity B and acceleration voltage Vacc). The magnetic field is collimated and intensifies the plasma that enhances the extracted beam current. The obtained cold cathode ion source can be used in different applications like surface etching, surface modification and deposition due to its long life and compactness

Effect of Microalloying Elements on the Heat Treatment Response and Tensile Properties of Al-Si-Mg Alloys

This study was carried out on a series of heat-treatable Al-Si-Mg alloys to determine the effects of Fe, Mg, Sr and Be addition on their microstructural characteristics and tensile properties. The results showed that the eutectic temperature was reduced by 10°C with 0.8 wt% Mg addition. The solidification curves and first derivatives of Sr-free alloys with high Fe and Mg contents revealed a peak at 611°C consequent to the formation of a script-like Be-Fe (Al8Fe2BeSi) phase, which was very close to the peak for α-Al. The morphology of the β-iron platelets underwent changes due to their dissolution, thinning, necking, and fragmentation with increase in solutionizing time. Increased Mg contents are beneficial to the tensile properties unlike the detrimental effect of increasing Fe contents. Additions of Be and Sr noticeably improved the properties at the same Fe and/or Mg contents, the enhancements being markedly observed at higher Mg contents and reduced Fe levels. At high Fe levels, addition of Be is preferable as it neutralizes the deleterious effects of Fe in these alloys; however, addition of 500 ppm Be is inadequate for interacting with other alloying elements

Ion beam and discharge characteristics of cold cathode ion source

In this work, some developments in the acceleration system of cold cathode ion source have been constructed to produce broad beam to be used in different industrial applications. An electrostatic probe with electrical circuit is constructed for study the extracted ion beam distribution. Broad beam 25 mm with ion current in the range of 1 mA is extracted from the constructed extraction system. The obtained optimum distance between the extraction grid and acceleration grid is 3 mm. The characteristics are measured to investigate the ion beam current Ib as a function of different parameters (discharge voltage Vd, gas pressure P, magnetic field intensity B and acceleration voltage Vacc). The magnetic field is collimated and intensifies the plasma that enhances the extracted beam current. The obtained cold cathode ion source can be used in different applications like surface etching, surface modification and deposition due to its long life and compactness

A deep convolutional structure-based approach for accurate recognition of skin lesions in dermoscopy images

One-third of all cancer diagnoses worldwide are skin malignancies. One of the most common tumors, skin cancer can develop from a variety of dermatological conditions and is subdivided into different categories based on its textile, color, body, and other morphological characteristics. The most effective strategy to lower the mortality rate of melanoma is early identification because skin cancer incidence has been on the rise recently. In order to categorize dermoscopy images into the four diagnosis classifications of melanoma, benign, malignant, and human against machine (HAM) not melanoma, this research suggests a computer-aided diagnosis (CAD) system. Experimental results show that the suggested approach enabled 97.25% classification accuracy. In order to automate the identification of skin cancer and expedite the diagnosis process in order to save a life, the proposed technique offers a less complex and cutting-edge framework