Fluid Dynamics of Vortex Formation in Tundish Operations: Mathematical Modelling

A mathematical model was developed to study the significance of the fluid dynamics of vortex formation in tundish operations. The aim is to contribute to the fundamental understanding of vortex formation and related phenomena. For this purpose a typical slab tundish was employed; the mathematical model was solved using FLUENT® commercial software capable to simulate highly turbulent flows. The well known k‐? turbulence model was applied to compute this effect in the process. The mathematical simulations confirmed the results from a water analogue model. The vortex formation is directly related to the highly turbulent flows present in the reactor. Great changes in velocity fields during short times and large distances between the upper edge of the dam and the free surface of the bath enhance the formation of vortex flows.     

Double mitral valve orifice. Two-dimensional and Doppler echocardiographic diagnosis

A thirty three-year-old male complaining of vomiting was diagnosed as having type 3 advanced gastric cancer of upper stomach and multiple liver metastasis, and had undergone total gastrectomy. The conclusive stage was P2H2n4se stage IVb. Intraoperatively, ethanol injection was performed for the liver metastasis under ultrasonography, and CDDP 100 mg was injected into the intra-abdominal cavity. Postoperative adjuvant therapy was added using oral fluorouracil and OK-432. Then we utilized FP chemotherapy (consisting of 5-FU and cisplatin) and radiotherapy for the bone metastasis. The patient survived 4 years and 4 months with good quality of life.     

A document is known by the company it keeps: neighborhood consensus for short text categorization

During the last decades the Web has become the greatest repository of digital information. In order to organize all this information, several text categorization methods have been developed, achieving accurate results in most cases and in very different domains. Due to the recent usage of Internet as communication media, short texts such as news, tweets, blogs, and product reviews are more common every day. In this context, there are two main challenges; on the one hand, the length of these documents is short, and therefore, the word frequencies are not informative enough, making text categorization even more difficult than usual. On the other hand, topics are changing constantly at a fast rate, causing the lack of adequate amounts of training data. In order to deal with these two problems we consider a text classification method that is supported on the idea that similar documents may belong to the same category. Mainly, we propose a neighborhood consensus classification method that classifies documents by considering their own information as well as information about the category assigned to other similar documents from the same target collection. In particular, the short texts we used in our evaluation are news titles with an average of 8 words. Experimental results are encouraging; they indicate that leveraging information from similar documents helped to improve classification accuracy and that the proposed method is especially useful when labeled training resources are limited.     

High-Throughput Magnetic Actuation Platform for Evaluating the Effect of Mechanical Force on 3D Tumor Microenvironment

Accurately replicating and analyzing cellular responses to mechanical cues is vital for exploring metastatic disease progression. However, many of the existing in vitro platforms for applying mechanical stimulation seed cells on synthetic substrates. To better recapitulate physiological conditions, a novel actuating platform is developed with the ability to apply tensile strain on cells at various amplitudes and frequencies in a high-throughput multi-well culture plate using a physiologically relevant substrate. Suspending fibrillar fibronectin across the body of the magnetic actuator provides a matrix representative of early metastasis for 3D cell culture that is not reliant on a synthetic substrate. This platform enables the culturing and analysis of various cell types in an environment that mimics the dynamic stretching of lung tissue during normal respiration. Metabolic activity, YAP activation, and morphology of breast cancer cells are analyzed within one week of cyclic stretching or static culture. Further, matrix degradation is significantly reduced in breast cancer cell lines with metastatic potential after actuation. These new findings demonstrate a clear suppressive cellular response due to cyclic stretching that has implications for a mechanical role in the dormancy and reactivation of disseminated breast cancer cells to macrometastases.     

SPH and FEM Investigation of Hydrodynamic Impact Problems

Simulation of hydrodynamic impact problems and its effect on surrounding structures, can be considered as a fluid structure coupling problem. The application is mainly used in automotive and aerospace engineering and also in civil engineering. Classical FEM and Finite Volume methods were the main formulations used by engineers to solve these problems. For the last decades, new formulations have been developed for fluid structure coupling applications using mesh free methods as SPH method, (Smooth Particle Hydrodynamic) and DEM (Discrete Element Method). Up to these days very little has been done to compare different methods and assess which one would be more suitable. In this paper the mathematical and numerical implementation of the FEM and SPH formulations for hydrodynamic problem are described. From different simulations, it has been observed that for the SPH method to provide similar results as FEM Lagrangian formulations, the SPH meshing, or SPH particle spacing needs to be finer than FEM mesh. To validate the statement, we perform a simulation of a hydrodynamic impact on an elasto-plastic plate structure. For this simple, the particle spacing of SPH method needs to be at least two times finer than FEM mesh. A contact algorithm is performed at the fluid structure interface for both SPH and FEM formulations. In the paper the efficiency and usefulness of two methods, often used in numerical simulations, are compared.     

Heavy metals contamination in soils around tailing heaps with various degrees of weathering in Zimapán,Mexico

Dispersion of mine tailings is the main cause of heavy metal (HM) contamination in soils in Zimapán, Mexico; however, the extent of this problem has not been assessed. Therefore, the aims of this study were to determine the degree of contamination and to assess the influence of mine tailings with different degrees of weathering on the spatial distribution of HM in soils. Soil and mine tailing sampling was carried out. The HM concentration was determined by atomic absorption spectrophotometry; spatial analysis and the size of the contaminated areas were calculated using GIS software; the mine tailings were characterized physically, chemically and mineralogically. The results suggest that all the tailing heaps have contributed to the HM dispersion. High HM concentrations were founded in soils around mine tailings (9402 mg kg^?1 Pb and 52 mg kg^?1 Cd). Surface area contaminated with Pb and Cd was estimated at 6.2 and 2.7 km², in urban soils, respectively.     

Engineered Fibrillar Fibronectin Networks as Three‐Dimensional Tissue Scaffolds

Extracellular matrix (ECM) proteins, and most prominently, fibronectin (Fn), are routinely used in the form of adsorbed pre‐coatings in an attempt to create a cell‐supporting environment in both two‐ and three‐dimensional cell culture systems. However, these protein coatings are typically deposited in a form which is structurally and functionally distinct from the ECM‐constituting fibrillar protein networks naturally deposited by cells. Here, the cell‐free and scalable synthesis of freely suspended and mechanically robust three‐dimensional (3D) networks of fibrillar fibronectin (fFn) supported by tessellated polymer scaffolds is reported. Hydrodynamically induced Fn fibrillogenesis at the three‐phase contact line between air, an Fn solution, and a tessellated scaffold microstructure yields extended protein networks. Importantly, engineered fFn networks promote cell invasion and proliferation, enable in vitro expansion of primary cancer cells, and induce an epithelial‐to‐mesenchymal transition in cancer cells. Engineered fFn networks support the formation of multicellular cancer structures cells from plural effusions of cancer patients. With further work, engineered fFn networks can have a transformative impact on fundamental cell studies, precision medicine, pharmaceutical testing, and pre‐clinical diagnostics.     

Modeling Study of the Vortex and Short Circuit Flow Effect on Inclusion Removal in a Slab Tundish

A mathematical model was developed to study effects of the vortex and the short circuit flow phenomena during tundish operation on the inclusion removal for a wide range of particle diameters. The model was solved using FLUENT® commercial software; for the particle tracking the Lagrangian discrete phase model was employed. Even when the vortexes drag about 50% of the inclusions, the most detrimental phenomenon for inclusion removal is the short circuit flow. It is important to stress that for the global inclusion behavior the removal rate decreases as the tundish level increases. It can be concluded that when increasing the tundish capacity without any flow control device adjustment, the steel cleanliness is deteriorated significantly.