An Eulerian projection method for quasi-static elastoplasticity

A well-established numerical approach to solve the Navier--Stokes equations for incompressible fluids is Chorin's projection method, whereby the fluid velocity is explicitly updated, and then an elliptic problem for the pressure is solved, which is used to orthogonally project the velocity field to maintain the incompressibility constraint. In this paper, we develop a mathematical correspondence between Newtonian fluids in the incompressible limit and hypo-elastoplastic solids in the slow, quasi-static limit. Using this correspondence, we formulate a new fixed-grid, Eulerian numerical method for simulating quasi-static hypo-elastoplastic solids, whereby the stress is explicitly updated, and then an elliptic problem for the velocity is solved, which is used to orthogonally project the stress to maintain the quasi-staticity constraint. We develop a finite-difference implementation of the method and apply it to an elasto-viscoplastic model of a bulk metallic glass based on the shear transformation zone theory. We show that in a two-dimensional plane strain simple shear simulation, the method is in quantitative agreement with an explicit method. Like the fluid projection method, it is efficient and numerically robust, making it practical for a wide variety of applications. We also demonstrate that the method can be extended to simulate objects with evolving boundaries. We highlight a number of correspondences between incompressible fluid mechanics and quasi-static elastoplasticity, creating possibilities for translating other numerical methods between the two classes of physical problems.Comment: 49 pages, 20 figure

Kamenev type oscillation criteria for nonlinear difference equations

summary:By means of Riccati transformation techniques, we establish some new oscillation criteria for second-order nonlinear difference equation which are sharp

Family Efficacy within Ethnically Diverse Families: A Qualitative Study

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136302/1/famp12149.pd

Impacts of Large-Scale Circulation on Convection: A 2-D Cloud Resolving Model Study

Studies of impacts of large-scale circulation on convection, and the roles of convection in heat and water balances over tropical region are fundamentally important for understanding global climate changes. Heat and water budgets over warm pool (SST=29.5 C) and cold pool (SST=26 C) were analyzed based on simulations of the two-dimensional cloud resolving model. Here the sensitivity of heat and water budgets to different sizes of warm and cold pools is examined

Fine Needle Aspiration Cytology of Metastatic Plasmacytoid Urothelial Carcinoma- Report of Four Cases Including a Case of Mixed Plasmacytoid and Micropapillary Morphology

Objectives: The aim of this study was to report a small series of fine-needle aspiration (FNA) cytology of the plasmacytoid variant of urothelial carcinoma (PVUC). Study Design: A computerized search of our laboratory information system was performed for the 5-year period between January 2008 and January 2013 to identify all FNA cases in which the corresponding surgical pathology cases were diagnosed as PVUC. Results: The 4 cases identified were from 2 men (aged 56 and 64 years) and 2 women (aged 72 and 46 years). The FNA smears demonstrated low-to-moderate cellularity and consisted predominantly of single and dyshesive, medium-sized tumor cells with eccentrically located nuclei and a moderate-to-abundant dense cytoplasm. The nuclei were oval with slightly irregular nuclear membranes and contained coarse granular chromatin with inconspicuous or small nucleoli. There was moderate nuclear variation in size. The nuclear-to-cytoplasmic ratio ranged from <1 to 3. Binucleation, cytoplasmic vacuoles, and perinuclear hof were occasionally seen. Conclusions: FNA cytology of PVUC shares features with plasma cell neoplasms, lobular carcinoma of the breast, and signet ring cell carcinoma of the stomach. Being aware of the patient's clinical history and the potential diagnostic pitfall of this rare variant of urothelial carcinoma is important for an accurate diagnosis on FNA biopsy

Expression and Significance of RANTES and MCP-1 in Renal Tissue With Chronic Renal Allograft Dysfunction

AbstractBackgroundTo investigate the expression of RANTES (regulated upon activation, normal T-cell–expressed and –secreted) and monocyte chemoattractant protein–1 (MCP-1) in renal allografts with chronic renal allograft dysfunction (CRAD), and explore its relationship with interstitial fibrosis and tubular atrophy (IF/TA).MethodsAn immunohistochemical assay and computer-assisted, genuine colored image analysis system were used to detect the expression of RANTES and MCP-1 in renal allografts with CRAD. The relationship among the expression level of MCP-1, RANTES, and the grade of inflammatory cell infiltration, interstitial fibrosis, and tubular atrophy in renal allografts were analyzed. Ten specimens of healthy renal tissue were used as controls.ResultsCompared to the normal tissues, the expressions of RANTES and MCP-1 were significantly higher in the renal tissues with CRAD (P < .001), and the expressions tended to increase along with the pathological grade of IF/TA. The expression of RANTES and MCP-1 were positively correlated with the pathological grades of IF/TA (r = 0.940 and 0.954 respectively, P < .001 for both).ConclusionIn renal allograft tissue with CRAD, the up-regulated expressions of RANTES and MCP-1 may be related to the progression of chronic renal allograft dysfunction and allograft fibrosis

Drilling data quality improvement and information extraction with case studies

Data analytics is a process of data acquiring, transforming, interpreting, modelling, displaying and storing data with an aim of extracting useful information, so that decision-making, actions executing, events detecting and incidents managing can be handled in an efficient and certain manner. However, data analytics also meets some challenges, for instance, data corruption due to noises, time delays, missing and external disturbances, etc. This paper focuses on data quality improvement to cleanse, improve and interpret the post-well or real-time data to preserve and enhance data features, like accuracy, consistency, reliability and validity. In this study, laboratory data and field data are used to illustrate data issues and show data quality improvements with using different data processing methods. Case study clearly demonstrates that the proper data quality management process and information extraction methods are essential to carry out an intelligent digitalization in oil and gas industry.publishedVersio