Influence of Quenching Agents on Mechanical, Wear, and Fracture Characteristics of Al2O3 / MoS2 Reinforced Al-6061 Hybrid Metal Matrix Composite (MMCs)

Aluminium (Al) based composites enhance the mechanical and wear behavior by heat treatment. The quenching factors like cooling agent, cooling rate and temperature of cooling are expected to influence the hardness, tensile, and wear behavior of the Al MMCs. This research shows the outcomes of a sequence of experiments to find the wear and mechanical behavior of the Al6061-Al2O3-MoS2 hybrid composites are quenched with different quenching agents. Hardening of the developed hybrid composites was carried out at 510ºC for the time period of 2 hours. Later, the same composite samples were quenched in ice cubes and water separately. Finally, age-hardening was done at 180ºC temperature for 4 hours and then the samples were cooled under room temperature. Heat treated hybrid composites were subjected to evaluate the hardness, tensile, and wear behavior. The outcomes reveal that the heat treatment significantly enhances the wear and mechanical behavior of hybrid composites. High mechanical strength and improved wear characteristics were observed in the hybrid composites which were quenched using ice cubes. The fractured surface of the tensile test samples and the wornout surface of wear test specimens were studied using a SEM analysis

Experimental studies of different quenching media on mechanical and wear behavior of Al7075/SiC/Al2O3 hybrid composites

The effects of SiC-Al2O3 particle in the Al alloy on the mechanical and wear characteristics of stir-casted Composites have been reported. The Al7075 is reinforced with 2, 4, 6 and 8 wt. % of (SiC + Al2O3) to manufacture the hybrid composite. Ceramic particulates were added into Al alloy to achieve the low wear rate and improving mechanical properties. Hardening of casted specimens at 480ºC for the duration of 2 hrs and the specimens were quenched into two different quenching media (water and ice cubes). Finally, age-hardening were carried out at the temperature of 160ºC for the duration of 4 hrs and cooled at room temperature. The tensile strength, hardness and wear behaviour of MMCs are evaluated on the un-treated and heat treated composite. The tensile strength and hardness of MMCs increases by incorporating SiC-Al2O3 particulates. The wear behaviour of the MMCs containing SiC-Al2O3 particulates revealed the high wear-resistance. The heat-treatment had considerably improved the properties when compared to the un-heat treated composites. The composites with the highest tensile strength, hardness and enhanced wear resistance were found in the composites quenched in ice cubes. Worned surfaces of the composite specimens were studied by using SEM and XRD analysi

Study on Micro-structure, Hardness and Optimization of Wear Characteristics of Al6061/TiB2/CeO2 Hotrolled MMCs using Taguchi Method

Aluminium composites are extensively used in several industrial applications. The production of Metal Matrix Composite (MMCs) with varying wt. % of reinforcement/s leads to enhancement of wear and mechanical behavior. In the present work, the varying wt. % of TiB2 and constant wt. % of CeO2 particulates were reinforced in Al6061 alloy to manufacture hybrid Al MMCs by Vortex (Stircasting) technique. Developed hybrid MMCs were hotrolled at 515°C of temperature. Hardness of hybrid MMCs was evaluated by using hardness test rig (Vickers). Result revealed that the hardness strength of developed hybrid MMCs increased with increase of the reinforcement content. The rate of wear of developed hybrid MMCs was evaluated by using Pin on Disc wear test. Test trials were conducted according to Taguchi technique. L27 array was implemented for evaluation of data. Effect of varying factors on the rate of wear and COF was analyzed by applying ANOVA (Analysis of Variance) method. ANOVA outcomes showed that the reinforcement content had a more significant impact on wear behavior and COF of the MMCs. Finally, L27 array outcomes were verified through confirmation experiments. A wear fractography outcome shows the internal fractured structure of a wear specimen which was studied using a SEM

Mechanical, Wear, and Fracture Behavior of Titanium Diboride (TiB2) - Cerium Oxide (CeO2) Reinforced Al-6061 Hot-rolled Hybrid Composites

Development of aluminium composites by stircasting technique is an effective method for fabrication of better quality of MMCs. Stircasting technique is one of the most commonly accepted techniques. In this research work, Al6061 / TiB2+CeO2 hybrid MMCs have been fabricated with varying wt. % of TiB2 (2.5%, 5%, 7.5% and 10%) particulates and constant 5% of CeO2 particulates. The monolithic alloy and hybrid composite were hot-rolled at a temperature of 515°C. Whereas, both the monolithic and hot-rolled hybrid composite was subjected to micro-structural study, hardness and tensile test. Optical microscope analysis revealed uniform dispersal of hard particles with in the base matrix in case of both of ascast and hot-rolled composites. Both ascast and hotrolled hybrid composites have shown extensive enhanced mechanical behavior and high wear resistance when compared with monolithic alloy. Though, ductility of the hybrid MMCs decreased with increasing TiB2 and CeO2 content. A tensile and wear fractography outcome shows the internal fractured structure of a tensile and wear specimen which was analysed using a SEM analysis

Wear characterization of Al 7075 alloy hybrid composites

Aluminium alloy hybrid composites are in high demand for advanced scientific applications due to their high strength, low weight, and enhanced tribological properties. A hybrid composite of aluminium alloy (Al7075) and aluminium oxide (Al2O3) and E-glass shot fibres was produced using a sand moulding technique in an electric resistance furnace. The objective of this research was to look at the wear characteristics of Al7075-Al2O3-E-glass hybrid composites with various Al2O3 (3-12%) and E-glass weight percentages (2-6 percent). The sliding distance (500, 1000, and 1500 m), load (10, 20, and 30N), Al2O3 (3, 6, and 9 %), and E-glass (2-6 %) are the wear characteristics that are considered. Wear testing is carried out using pin-on-disc equipment (WTE 165 model, Version-EV00) in line with the Taguchi L9 orthogonal array. Taguchi analysis was done on the collected data to find SN plots. Regression analysis was done along with ANOVA to find relationships between different factors selected. In order to reduce the wear rate of hybrid composites, the optimal wear parameters are determined. As the percentage of reinforcements increased, the rate of deterioration decreased. SEM scans revealed the attachment and displacement of unintended wear debris, as well as the uniform distribution of Al2O3/E-glass particles

Influence of quenching agents on mechanical, wear, and fracture characteristics of Al2O3 / MoS2 reinforced Al-6061 hybrid Metal Matrix Composite (MMCs)

Aluminium (Al) based composites enhance the mechanical and wear behavior by heat treatment. The quenching factors like cooling agent, cooling rate and temperature of cooling are expected to influence the hardness, tensile, and wear behavior of the Al MMCs (Metal Matrix Composites). This research shows the outcomes of a sequence of experiments conducted to study the mechanical and wear behavior of the Al6061-Al2O3-MoS2 hybrid composites that are quenched with different quenching agents. Heat treated hybrid composites were subjected to evaluate the hardness, tensile, and wear behavior. The outcomes reveal that the heat treatment significantly enhances the mechanical and wear behavior of hybrid composites. Highest hardness of 138.1 VHN was achieved under the ice quenched samples. The mechanical and wear behavior improved under the ice quenched samples. Voids, particle pullouts and dimples were observed in the tensile fractured surface. Micro pits, delamination layers, ploughing and micro fissures were observed in the wornout surface of the wear test samples

PTEN loss mediated Akt activation promotes prostate tumor growth and metastasis via CXCL12/CXCR4 signaling

Abstract Introduction The chemokine CXCL12, also known as SDF-1, and its receptor, CXCR4, are overexpressed in prostate cancers and in animal models of prostate-specific PTEN deletion, but their regulation is poorly understood. Loss of the tumor suppressor PTEN (phosphatase and tensin homolog) is frequently observed in cancer, resulting in the deregulation of cell survival, growth, and proliferation. We hypothesize that loss of PTEN and subsequent activation of Akt, frequent occurrences in prostate cancer, regulate the CXCL12/CXCR4 signaling axis in tumor growth and bone metastasis. Methods Murine prostate epithelial cells from PTEN+/+, PTEN +/− , and PTEN−/− (prostate specific knockdown) mice as well as human prostate cancer cell lines C4-2B, PC3, and DU145 were used in gene expression and invasion studies with Akt inhibition. Additionally, HA-tagged Akt1 was overexpressed in DU145, and tumor growth in subcutaneous and intra-tibia bone metastasis models were analyzed. Results Loss of PTEN resulted in increased expression of CXCR4 and CXCL12 and Akt inhibition reversed expression and cellular invasion. These results suggest that loss of PTEN may play a key role in the regulation of this chemokine activity in prostate cancer. Overexpression of Akt1 in DU145 resulted in increased CXCR4 expression, as well as increased proliferation and cell cycle progression. Subcutaneous injection of these cells also resulted in increased tumor growth as compared to neo controls. Akt1 overexpression reversed the osteosclerotic phenotype associated with DU145 cells to an osteolytic phenotype and enhanced intra-osseous tumor growth. Conclusions These results suggest the basis for activation of CXCL12 signaling through CXCR4 in prostate cancer driven by the loss of PTEN and subsequent activation of Akt. Akt1-associated CXCL12/CXCR4 signaling promotes tumor growth, suggesting that Akt inhibitors may potentially be employed as anticancer agents to target expansion of PC bone metastases

Mechanical, wear, and fracture behavior of Titanium Diboride (TiB2) - Cerium Oxide (CeO2) reinforced Al-6061 hot-rolled hybrid composites

Development of aluminium composites by stircasting technique is an effective method for fabrication of better quality of MMCs. Stircasting technique is one of the most commonly accepted techniques. In this research work, Al6061 / TiB2+CeO2 hybrid MMCs have been fabricated with varying wt. % of TiB2 (2.5%, 5%, 7.5% and 10%) particulates and constant 5% of CeO2 particulates. The monolithic alloy and hybrid composite were hot-rolled at a temperature of 515�C. Both the monolithic and hot-rolled hybrid composites were subjected to micro-structural study, hardness and tensile test. Optical microscope analysis revealed uniform dispersal of hard particles within the base matrix in case of both of ascast and hot-rolled composites. Both ascast and hotrolled hybrid composites showed extensive enhanced mechanical behavior and high wear resistance when compared with monolithic alloy. Hot rolled MMCs showed enhancement of 25 % of hardness when compared with monolithic alloy with increasing reinforcement of 2.5 - 10 wt. % of TiB2 content. Tensile strength increased by 53.54 % for hot rolled composites when compared to the as cast and other hybrid composites. Tensile and wear fractography outcome showed internal fractured structure of a tensile and wear specimen which was analysed using SEM analysis

A survey on detecting healthcare concept drift in AI/ML models from a finance perspective

Data is incredibly significant in today's digital age because data represents facts and numbers from our regular life transactions. Data is no longer arriving in a static form; it is now arriving in a streaming fashion. Data streams are the arrival of limitless, continuous, and rapid data. The healthcare industry is a major generator of data streams. Processing data streams is extremely complex due to factors such as volume, pace, and variety. Data stream classification is difficult owing to idea drift. Concept drift occurs in supervised learning when the statistical properties of the target variable that the model predicts change unexpectedly. We focused on solving various forms of concept drift problems in healthcare data streams in this research, and we outlined the existing statistical and machine learning methodologies for dealing with concept drift. It also emphasizes the use of deep learning algorithms for concept drift detection and describes the various healthcare datasets utilized for concept drift detection in data stream categorization

PKCθ Regulates T Cell Motility via Ezrin-Radixin-Moesin Localization to the Uropod

Cell motility is a fundamental process crucial for function in many cell types, including T cells. T cell motility is critical for T cell-mediated immune responses, including initiation, activation, and effector function. While many extracellular receptors and cytoskeletal regulators have been shown to control T cell migration, relatively few signaling mediators have been identified that can modulate T cell motility. In this study, we find a previously unknown role for PKCθ in regulating T cell migration to lymph nodes. PKCθ localizes to the migrating T cell uropod and regulates localization of the MTOC, CD43 and ERM proteins to the uropod. Furthermore, PKCθ-deficient T cells are less responsive to chemokine induced migration and are defective in migration to lymph nodes. Our results reveal a novel role for PKCθ in regulating T cell migration and demonstrate that PKCθ signals downstream of CCR7 to regulate protein localization and uropod formation.</p