Analysis and quantification of mechanical properties of various DHP copper tubes manufacturing processes using drift expanding test

Deoxidized High Phosphorus (DHP) Copper tubes are frequently used in numerous industrial and household applications. To ensure the acceptability of DHP copper tubes prepared by various industrial processes, the quality of the DHP copper tubes must be evaluated. Drift expanding test is one of the best ways to do so is to examine the quality of tubes. In this paper the authors considered the mechanical properties of various DHP copper tubes manufacturing processes using drift expanding test. This paper concludes that there is a large difference in the mechanical properties of tubes with different manufacturing methods. Planetary rolling have a better expanding percentage than cast or extruded tube samples.</p

Effect of antimony addition relative to microstructure and mechanical properties of continuous cast lead alloy

It is well documented that the addition of antimony in pure lead increases tensile strength and reduced elongation. The goal of the present work is to identify the cause of these phenomena by investigation of the effects of the addition of Sb (1.25 wt.%) on the structure of pure continuously cast lead and lead alloy rods. The microstructure and morphology of both pure lead and lead with 1.25 wt.% antimony were examined by digital optical microscope and scanning electron microscope respectively. Energy Dispersive X-ray Spectroscopy (EDX) was used to identify alloying elements. The results showed that the effect of additions of antimony on mechanical properties of lead-antimony alloys is mainly due to the solid solubility of the antimony. Distribution of the antimony results in a decrease in the grain size of the pure lead. These smaller grains mean higher strength so long as there is a homogeneous grain structure.</p

Influence of casting speed on the structure and mechanical properties of continuous cast DHP copper tube

DHP Copper tubes are frequently used in industrial applications with their unique characteristics such as high corrosion or excellent erosion resistance. Due to the requirement of good quality production, an excellent global factor is needed for the purpose of obtaining high mechanical properties. A mechanical properties has correlation with grain size and a high mechanical properties is achieved by small grain structure. There are three ways in which grain size can be altered: by thermal means, chemical means and by mechanical means. This paper looks at the first case, thermal means, which has very substantial cost benefits over the other two types of grain refinement in that it does not require large pieces of equipment that vibrate or mix and does not use any exotic metals as feed stock. Instead what thermal methods require is a change in parameters like: casting speed, liquid metal temperature or cooling water temperature. In this work, characterization of the influence of casting speed on the structure and mechanical properties of continuous cast DHP copper tube has been carried out by drift expanding test and grain size reading. A significant different based on grain structure has been investigated and it was also found that the casting speed could improve the elongation of samples from 29 % expanding to 36 % expanding

Loss of apical monocilia on collecting duct principal cells impairs ATP secretion across the apical cell surface and ATP-dependent and flow-induced calcium signals

Renal epithelial cells release ATP constitutively under basal conditions and release higher quantities of purine nucleotide in response to stimuli. ATP filtered at the glomerulus, secreted by epithelial cells along the nephron, and released serosally by macula densa cells for feedback signaling to afferent arterioles within the glomerulus has important physiological signaling roles within kidneys. In autosomal recessive polycystic kidney disease (ARPKD) mice and humans, collecting duct epithelial cells lack an apical central cilium or express dysfunctional proteins within that monocilium. Collecting duct principal cells derived from an Oak Ridge polycystic kidney (orpkTg737) mouse model of ARPKD lack a well-formed apical central cilium, thought to be a sensory organelle. We compared these cells grown as polarized cell monolayers on permeable supports to the same cells where the apical monocilium was genetically rescued with the wild-type Tg737 gene that encodes Polaris, a protein essential to cilia formation. Constitutive ATP release under basal conditions was low and not different in mutant versus rescued monolayers. However, genetically rescued principal cell monolayers released ATP three- to fivefold more robustly in response to ionomycin. Principal cell monolayers with fully formed apical monocilia responded three- to fivefold greater to hypotonicity than mutant monolayers lacking monocilia. In support of the idea that monocilia are sensory organelles, intentionally harsh pipetting of medium directly onto the center of the monolayer induced ATP release in genetically rescued monolayers that possessed apical monocilia. Mechanical stimulation was much less effective, however, on mutant orpk collecting duct principal cell monolayers that lacked apical central monocilia. Our data also show that an increase in cytosolic free Ca2+ primes the ATP pool that is released in response to mechanical stimuli. It also appears that hypotonic cell swelling and mechanical pipetting stimuli trigger release of a common ATP pool. Cilium-competent monolayers responded to flow with an increase in cell Ca2+ derived from both extracellular and intracellular stores. This flow-induced Ca2+ signal was less robust in cilium-deficient monolayers. Flow-induced Ca2+ signals in both preparations were attenuated by extracellular gadolinium and by extracellular apyrase, an ATPase/ADPase. Taken together, these data suggest that apical monocilia are sensory organelles and that their presence in the apical membrane facilitates the formation of a mature ATP secretion apparatus responsive to chemical, osmotic, and mechanical stimuli. The cilium and autocrine ATP signaling appear to work in concert to control cell Ca2+. Loss of a cilium-dedicated autocrine purinergic signaling system may be a critical underlying etiology for ARPKD and may lead to disinhibition and/or upregulation of multiple sodium (Na+) absorptive mechanisms and a resultant severe hypertensive phenotype in ARPKD and, possibly, other diseases