Simultaneous Evaporation Cu and Sn from Liquid Steel

In order to understand evaporation refining of tramp elements in molten ferrous scrap, Cu and Sn, a series of experiments were carried out using liquid-gas reaction in a levitation melting equipment. Effect of S and C, which are abundant in hot metal from ironmaking process, was examined and analyzed by employing a comprehensive evaporation kinetic model developed by the present authors (Jung et al. in Metall Mater Trans B 46B:250-258, 2014; Jung et al. in Metall Mater Trans B 46B:259-266, 2014; Jung et al. in Metall Mater Trans B 46B:267-277, 2014; Jung and Kang in Metall Mater Trans B ExternalRef RefSource10.1007/s11663-016-0601-5RefSource RefTarget Address="10.1007/s11663-016-0601-5" TargetType="DOI" ExternalRef, 2016). Evaporation of Cu and Sn were treated by evaporation of individual species such as Cu(g), CuS(g), Sn(g), and SnS(g), along with CS2(g). Decrease of Cu and Sn content in liquid steel was in good agreement with the model prediction. Optimum conditions of steel composition for the rapid evaporation of Cu and Sn were proposed by utilizing the model predictions.1132Ysciescopu

The Formation of Carbon Microcoils Having the Coil-Type Overall Geometry

Carbon microcoils could be synthesized using a thermal chemical vapor deposition process in which C2H2/H2 is used as the source gas and SF6 as an additive gas. We investigated the formation of carbon microcoils as a function of reaction time to study the growth mechanism of coil-type carbon microcoils, particularly under long reaction time. After the first 5 min of the reaction, wave-like carbon nanocoils were formed along with carbon microcoils at certain positions on the sample. An increase in reaction time (60 min) led to the formation of double helix-type carbon microcoils. Further increase in the reaction time (120 min) led to the formation of twist-type carbon microcoils with occasional growth of the coil-type carbon microcoils on the sample. However, at the longest reaction time (180 min) investigated in this work, we observed a decrease in the density of the carbon microcoils. Based on these results, we determine the optimal reaction time for the growth of double helix-type carbon microcoils and suggest the growth mechanism of the coil-type carbon microcoils with a focus on long reaction time

Self-Organization of Bioinspired Fibrous Surfaces

Nature uses fibrous surfaces for a wide range of functions such as sensing, adhesion, structural color, and self-cleaning. However, little is known about how fiber properties enable them to self-organize into diverse and complex functional forms. Using polymeric micro/nanofiber arrays with tunable properties as model systems, we demonstrate how the combination of mechanical and surface properties can be harnessed to transform an array of anchored nanofibers into a variety of complex, hierarchically organized dynamic functional surfaces. We show that the delicate balance between fiber elasticity and surface adhesion plays a critical role in determining the shape, chirality, and hierarchy of the assembled structures. We further report a strategy for controlling the long-range order of fiber assemblies by manipulating the shape and movement of the liquid-vapor interface. Our study provides fundamental understanding of the pattern formation by self-organization of bioinspired fibrous surfaces. Moreover, our new strategies offer a foundation for designing a vast assortment of functional surfaces with adhesive, optical, water-repellent, capture and release, and many more capabilities with the structural and dynamic sophistication of their biological counterparts.Engineering and Applied Science

Shape programmable structures

Shape programmable structures and devices are typically fabricated using shape memory materials and are attracting increasing interest because they can be designed to have multiple properties and functions. However, shape memory materials, such as NiTi-based metal alloys and block copolymers, suffer from severe structural -fatigue due to the microstructural changes occurring during each thermal cycle. Moreover, there is only a limited set of shape memory material systems, limiting the possible number of applications for reconfigurable structures and devices. To overcome all these issues and expand the range of applications of shape programmable structures, we designed a library of 2D elastic structures that can be programmed to retain multiple shapes simply by applying a force. The building block of our structure consists of a unit comprising interconnected elastic arches and we demonstrate both numerically and experimentally that geometric nonlinearity and snap-through instabilities can be effectively exploited to reconfigure the system into multiple shapes. Because our system exploits mechanical instability, our findings can be extended to different materials and length scales, outlining a general strategy to effectively design a new generation of shape programmable structures

Evaporative printing of organic materials and metals and development of organic memories

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2004.Includes bibliographical references (p. 125-132).The advantages of directed printing make it the ideal fabrication tool for the ubiquitous electronic technologies of the future. However, direct printing techniques such as ink-jet technology, are currently limited to materials that can be processed in solution. We developed a novel micro-machined print head capable of expanding the capabilities of inkjet printing to metals and molecules that are suited for evaporative deposition. Deposition of metals is particularly desirable advantage of the proposed printer. We demonstrate arbitrary organic and metal patterns by printing, with the line width modulated by controlling the micro-machined shutter. With the challenges and solutions for ambient pressure printing are also studied. Additionally, the printer can be used for organic crystal formation, and controlled doping. In the second part of the thesis we examine charge trapping and storage in organic thin film devices. We demonstrate that by controlled doping, we can engineer charge storage in active organic electronic devices. Charge trapping in organic hetero-junction structures results in two distinct phenomena that both manifest as a memory behavior. Trapped charge can (1) increase the carrier mobility in organic structures, (2) generate current during the de-trapping process. Both processes are demonstrated in practical structures.by Sung Hoon Kang.S.M

A unique bleeding-related complication of sorafenib, a tyrosine kinase inhibitor, in advanced hepatocellular carcinoma: a case report

INTRODUCTION: Sorafenib, a multikinase inhibitor as a standard of care for advanced hepatocellular carcinoma, may lead endothelial cells to an unstable state by blocking the signaling pathway of vascular endothelial growth factor receptor, which may result in the disruption of the architecture and integrity of the microvasculature, and eventually increase the risk of hemorrhage. Hemobilia is a relatively uncommon condition as a consequence of hepatocellular carcinoma and its risk factors remain uncertain. CASE PRESENTATION: Here we report a unique case of hemobilia occurring in a 55-year-old Korean man with hepatitis B virus-related hepatocellular carcinoma on Barcelona Clinic Liver Cancer advanced stage after seven days of treatment with sorafenib. He had received prior radiation therapy. Endoscopy revealed bleeding from the major duodenal papilla and endoscopic retrograde cholangiography revealed an amorphous filling defect throughout the common bile duct. Blood clots were removed by balloon sweeping and a nasobiliary drainage tube was placed. No further bleeding has been detected as of eight months after discontinuation of sorafenib. CONCLUSION: Sorafenib may increase the risk of biliary bleeding in hepatocellular carcinoma patients who were primed with irradiation, by blocking the signaling pathway of the vascular endothelial growth factor receptor. Therefore, sorafenib should be used with caution in patients with advanced hepatocellular carcinoma, especially when combined with radiation therapy

Carpal Tunnel Syndrome Caused by Space Occupying Lesions

PURPOSE: To evaluate the diagnosis and treatment of the carpal tunnel syndrome (CTS) due to space occupying lesions (SOL). MATERIALS and METHODS: Eleven patients and 12 cases that underwent surgery for CTS due to SOL were studied retrospectively. We excluded SOL caused by bony lesions, such as malunion of distal radius fracture, volar lunate dislocation, etc. the average age was 51 years. There were 3 men and 8 women. Follow-up period was 12 to 40 months with an average of 18 months. the diagnosis of CTS was made clinically and electrophysiologically. in patients with swelling or tenderness on the area of wrist flexion creases, magnetic resonance imaging (MRI) and/or computed tomogram (CT) were additionally taken as well as the carpal tunnel view. We performed conventional open transverse carpal ligament release and removal of SOL. RESULTS: the types of lesion confirmed by pathologic examination were; tuberculosis tenosynovitis in 3 cases, nonspecific tenosynovitis in 2 cases, and gout in one case. Other SOLs were tumorous condition in five cases, and abnormal palmaris longus hypertrophy in 1 case. Tumorous conditions were due to calcifying mass in 4 cases and ganglion in 1 case. Following surgery, all cases showed alleviation of symptom without recurrence or complications. CONCLUSION: in cases with swelling or tenderness on the area of wrist flexion creases, it is important to obtain a carpal tunnel view, and MRI and/or CT should be supplemented in order to rule out SOLs around the carpal tunnel, if necessary.ope

Endoplasmic Reticulum Stress in the β-Cell Pathogenesis of Type 2 Diabetes

Type 2 diabetes is a complex metabolic disorder characterized by high blood glucose in the context of insulin resistance and relative insulin deficiency by β-cell failure. Even if the mechanisms underlying the pathogenesis of β-cell failure are still under investigation, recent increasing genetic, experimental, and clinical evidence indicate that hyperactivation of the unfolded protein response (UPR) to counteract metabolic stresses is closely related to β-cell dysfunction and apoptosis. Signaling pathways of the UPR are “a double-edged sword” that can promote adaptation or apoptosis depending on the nature of the ER stress condition. In this paper, we summarized our current understanding of the mechanisms and components related to ER stress in the β-cell pathogenesis of type 2 diabetes

Harnessing Geometric Frustration to Form Band Gaps in Acoustic Channel Lattices

We demonstrate both numerically and experimentally that geometric frustration in two-dimensional periodic acoustic networks consisting of arrays of narrow air channels can be harnessed to form band gaps (ranges of frequency in which the waves cannot propagate in any direction through the system). While resonant standing wave modes and interferences are ubiquitous in all the analyzed network geometries, we show that they give rise to band gaps only in the geometrically frustrated ones (i.e. those comprising of triangles and pentagons). Our results not only reveal a new mechanism based on geometric frustration to suppress the propagation of pressure waves in specific frequency ranges, but also opens avenues for the design of a new generation of smart systems that control and manipulate sound and vibrations