Microstructure–mechanical property relationship in an Al–Mg alloy processed by constrained groove pressing-cross route

The constrained groove pressing-cross route process was implemented on a commercially annealed AA5052 alloy at room temperature, with up to two passes (strain of ～4.64) along the rolling direction and transverse direction. The results showed the formation of an ultrafine-grained structure with an average sub-grain/cell size in the 300–500?nm range. The indentation hardness and tensile strength increased significantly, up to ～75 and 105%, respectively, and became more homogenous with a uniform and isotropic trend, as compared to the annealed alloy. According to the Hall–Petch and Taylor models used, grain refinement and increasing dislocation density were proposed as the main strengthening mechanisms. Fractographic studies revealed a ductile-fracture behaviour, with a dimpled structure proportional to the UFG structure.     

Characterization of three novel monoclonal antibodies against hepatitis C virus core protein

Three novel monoclonal antibodies (MAbs) were established against a recombinant hepatitis C virus (HCV) core protein derived from cloned genotype 1b HCV cDNA. MAbs C7-50 and C8-59 recognize a conserved linear epitope represented by amino acid residues 21 to 40 of the nucleocapsid protein. MAb C8-48 is directed against a strain-specific conformational epitope located within the first 82 amino acids. A sensitive two-site MAb-based immunoradiometric assay was established using antibodies directed against distinct epitopes on the nucleocapsid protein. Processed 21 kDa core protein was detected by immunoblotting in human hepatocellular carcinoma cell lines and primary adult rat hepatocytes transfected with a cytomegalovirus promoter-driven expression construct. Immunofluorescence microscopy studies revealed a granular and vesicular cytoplasmic staining pattern. MAb C7-50 was used successfully to detect HCV core antigen in chronically infected chimpanzee liver tissue. These MAbs represent important reagents for the study of HCV biology and for the development of immunodiagnostic assays.     

Effects of growth rate of eastern poplar trees on the chemical and morphological characteristics of wood fibers

European Journal of Wood and Wood Products - Attempts are underway to speed up timber production using genetic improvement and enhanced management practices. However, the impacts of possible...     

Influence of nanofluids application on contact length during hard turning

The length of tool–chip contact area (L_c) is considered as a considerable parameter in metal cutting process. Mechanical stresses and high temperature at this region may easily lead to abrasion or even breakage of cutting tool. Up to now, several solutions have been presented to overcome these limitations. Using cutting fluids is one of the solutions to reduce friction, stresses, and temperature over this area. This paper presents experimental investigation and finite element simulation of tool–chip interface in hard turning AISI 4140 using TiO₂ nanofluids. Nanofluids are newly class of engineering fluids developed by distributing nanometer solid particles in a base fluid. The main reason to use nanofluids in cutting process is to increase heat transfer capabilities and also its tribological attributes. At first, the effects of cutting speed, nanoparticles’ size, and nanofluid concentration on L_c have been experimentally investigated. Then, a numerical model has been developed to simulate the contact area length in case of nanofluids application. Comparing the results with that of the experimental tests shows that TiO₂ nanofluids are able to decrease L_c, about 35%, in feed rate of 0.11 mm/rev, nanoparticle size equal to 10 nm, and nanofluid concentration equal to 3.0 wt%.     

CONTROLS ON RESERVOIR QUALITY IN THE LOWER TRIASSIC KANGAN FORMATION,SOUTHERN PERSIAN GULF

The Lower Triassic Kangan Formation together with the underlying Upper Permian Dalan Formation forms one of the most important reservoirs for natural gas in the Middle East. The carbonate‐dominated Kangan Formation was studied at a gasfield in the southern Persian Gulf and some 100 m of core were examined at micro‐ and macro scales. Twelve microfaaes were identified. Previous studies have divided the Kangan Formation reservoir into Lower (K2) and Upper (K1) Units. The Lower Kangan can divided into two subunits (K2b and K2a), while three subunits (K1c, K1b and K1a) are recognised in the Upper Kangan. Diagenetic processes have affected reservoir quality in the Kangan Formation in different ways. Processes improving reservoir quality include dissolution, dolomitization and fracturing, while reservoir quality was decreased by cementation, and chemical and mechanical compaction. Micritization and neomorphism have had both positive and negative effects. Fracture development has improved reservoir quality, particularly in dolomitic intervals.     

Tuberculous colitis mimicking Crohn's disease

Intestinal tuberculosis is a rare disease in western countries and may mimic a variety of gastrointestinal disorders. Here, we report the case of a 63-yr-old patient who presented with profuse bleeding from a deep rectal ulcer. Similar lesions were found in different parts of the colon. Multilocular colorectal carcinoma was suspected based on the macroscopic appearance. Histology, however, suggested Crohn's disease. Intestinal tuberculosis was initially ruled out by negative staining for acid-fast bacilli, mycobacterial culture, and polymerase chain reaction analysis. A treatment for Crohn's disease was started. Endoscopic reexamination revealed progressive disease with extensive ulcerations of the terminal ileum. Histopathological examination then revealed acid-fast bacilli in the colonic mucosa typical for mycobacterium tuberculosis infection. This case emphasizes the need to include intestinal tuberculosis in the initial differential diagnosis of ulcerative colorectal lesions also in the western population.