Development of Ultra-Carbon Steel Prepared by Mechanical Alloying and Subsequent Hot Pressing

It is known that the most effective way to improve mechanical properties of steels is by microstructural refinement. Iron and graphite powders mixture with hypoeutectoid composition were mechanically alloyed (MAed) and subsequently hot pressed (HPed) to provide steels with fine structure. Mechanical Alloying (MA) was carried out using a planetary ball mill for 100, 200 and 300 h, while HP at 41 MPa at various temperatures: 610ºC (below), 730ºC (near) and 800ºC (above the eutectoid transformation point A1). The mechanically alloyed (MAed) powders were characterized by X-ray diffraction (XRD), differential thermal analysis (DTA) and scanning electron microscopy (SEM). While, the HPed compacts were characterized by SEM, Vickers hardness and tensile test. During MA, refinement of crystallite, formations of super-saturated iron solid solution and Fe/C amorphous phase occured first. With further MA time, these phases might begin to transform to more stable phases such as carbides. In the case of HP at 610ºC (below A1), very fine cementites were precipitated in fine ferrite grain with sub-micron meter in the size. However, the mechanical properties cannot be attained because of low sinterability. At 730ºC (near A1), the strength reaches the maximum value. With further temperature increase (at 800ºC), the sintering progressed well and the coarsening occured, resulting the decrease in strength. However, the fracture strain increased significantly. The steels obtained in the present study had mechanical properties comparable to those of standard (JIS) steels through the welle stablished heat treatment such as normalizing and thermal refining

Distraction-Induced Intestinal Growth: The Role of Mechanotransduction Mechanisms in a Mouse Model of Short Bowel Syndrome

Novel strategies are needed to address the problem of patients with short bowel syndrome. We previously demonstrated a three-fold lengthening of pig bowel after 2 weeks of applied distractive forces, but we have not elucidated the mechanisms facilitating this growth. We used a mouse model of distraction-induced enterogenesis. High molecular weight polyethylene glycol (PEG) osmotically stretched an isolated small bowel segment (PEG-stretch). Significant increases in villus height and crypt depth and in intestinal epithelial cell length and numbers suggested epithelial remodeling in addition to proliferation during enterogenesis. LC-MS/MS analysis showed a two-fold upregulation of α-actinin-1 and -4. We also demonstrated that p-focal adhesion kinase (FAK), FAK, α-actinin, and Rac1 were significantly upregulated and that F-actin was relocalized in PEG-stretch versus controls. Blockade of the phosphotidyl inositol 3? kinase pathway failed to influence the increase in proliferation or decline in apoptosis after stretch, suggesting alternative signaling pathways are used, including MEK and P38MAPK, which were both upregulated during enterogenesis. Our data suggests that several known mechanotransduction pathways drive distraction-induced enterogenesis.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140227/1/ten.tea.2013.0383.pd

Quantification of lung perfusion blood volume by dual-energy CT in patients with and without chronic obstructive pulmonary disease

Purpose: In chronic obstructive pulmonary disease (COPD), pulmonary vascular alteration is one of the characteristic features. Recently, software has been used for the quantification of lung iodine perfusion blood volume (iPBV) using dual-energy CT, allowing objective evaluation. The purpose of this study was to evaluate the quantification of lung PBV with and without COPD. Materials and Methods: This study was approved by the Institutional Review Board. Sixty-two subjects who had undergone a respiratory function test within one month underwent dual-energy CT angiography. The subjects were divided into two groups: with (n=14) and without (n=48) COPD. We evaluated the quantification of lung iPBV in the early phase and late phase using Syngo softwarepost contrast. Associations between lung iPBV and respiratory function (forced expiratory volume in 1 second/forced vital capacity; FEV1/FVC) and the percentage area of emphysema (%LAA-950) were also evaluated. Results: In the early phase, lung iPBV values were 20.1±5.5 and 30.6±7.6 Hounsfield Unit (HU) in those with and without COPD, respectively, with a significant difference between them (Conclusions: Quantification of lung iPBV reflects reduced pulmonary perfusion in patients with COPD. It may be useful for objective evaluation of the pulmonary blood flow in patients with COPD

STUDI DASAR PELAPISAN INTERMETALLIC Al-Fe PADA PLAT BAJA DENGAN METODE MECHANICAL ALLOYING

STUDI DASAR PELAPISAN INTERMETALLIC Al-Fe PADA PLAT BAJA DENGAN METODE MECHANICAL ALLOYING. Akhir-akhir ini, pemaduan mekanik atau Mechanical Alloying (MA) mendapat perhatian akan kemampuannya untuk membentuk pelapisan pada permukaan partikel yang berstruktur nanometer. Struktur nanometer dapat memperbaiki berbagai sifat dari material seperti kecepatan difusi, dan keuletannya. Untuk mempelajari proses perubahan struktur pelapisan menggunakan metode Mechanical Alloying pada suhu kamar, dilakukan pelapisan dengan bubuk Al dan Al-25at% Fe (persen atom) pada plat baja dengan menggunakan planetary ball mill selama 80 jam, yang diatur suhunya dibawah 50 °C. Pelapisan bubuk Al tidak diperoleh, tetapi dengan penambahan 25at% Fe pelapisan dapat diperoleh. Penambahan Fe menstimulasi kristal Al untuk lebih mudah hancur dan menempel lebih baik. Ketebalan pelapisan yang terbentuk mencapai 250 μm. Pada Mechanical Alloying selama 80 jam, terbentuk amorf dari Al-25at% Fe dan intermetallic Al5Fe2

Endovascular repair of aortic dissection and intramural hematoma: indications and serial changes

Thoracic aortic dissection (AD) is one of the most common aortic emergencies. It can be fatal if not promptly diagnosed and treated. Intramural hematoma (IMH) of the aorta is recognized as distinct from classic (double-barreled) AD. IMH also frequently leads to aortic emergency, which can be fatal unless rapidly diagnosed and treated.Recently, thoracic endovascular aortic repair (TEVAR) has been used for the treatment of complications caused by AD. TEVAR is also a viable option for the treatment of complicated IHM. In this article, we review the details of TEVAR as treatment options for AD and IMH, including the indications for TEVAR, imaging, and follow-up

Measuring Incineration Plants' Performance using Combined Data Envelopment Analysis, Goal Programming and Mixed Integer Linear Programming

Incineration plants produce heat and power from waste, reduce waste disposal to landfills, and discharge harmful emissions and bottom ash. The objective of the incineration plant is to maximize desirable outputs (heat and power) and minimize undesirable outputs (emissions and bottom ash). Therefore, studying the overall impact of incineration plants in a region so as to maximize the benefits and minimize the environmental impact is significant. Majority of prior works focus on plant specific decision making issues including performance analysis. This study proposes a hybrid Data Envelopment Analysis (DEA), Goal Programming (GP) and Mixed Integer Linear Programming (MILP) model to assess the performance of incineration plants, in a specific region, to enhance overall power production, consumption of waste and reduction of emissions. This model not only helps the plant operators to evaluate the effectiveness of incineration but also facilitates the policy makers to plan for overall waste management of the region through decision-making on adding and closing plants on the basis of their efficiency. Majority of prior studies on incineration plants emphasize on how to improve their performance on heat and power production and neglect the waste management aspects. Additionally, optimizing benefits and minimizing negative outputs through fixing targets in order to make decision on shutting down the suboptimal plants has not been modeled in prior research. This research combines both the aspects and addresses the overall performance enhancement of incineration plants within a region from both policy makers and plant operators’ perspectives. The proposed combined DEA, GP and MILP model enables to optimize incineration plants performance within a region by deriving efficiency of each plant and identifying plants to close down on the basis of their performance. The proposed model has been applied to a group of 22 incineration plants in the UK using secondary data in order to demonstrate the effectiveness of the model.

Global Well-posedness of an Inviscid Three-dimensional Pseudo-Hasegawa-Mima Model

The three-dimensional inviscid Hasegawa-Mima model is one of the fundamental models that describe plasma turbulence. The model also appears as a simplified reduced Rayleigh-B\'enard convection model. The mathematical analysis the Hasegawa-Mima equation is challenging due to the absence of any smoothing viscous terms, as well as to the presence of an analogue of the vortex stretching terms. In this paper, we introduce and study a model which is inspired by the inviscid Hasegawa-Mima model, which we call a pseudo-Hasegawa-Mima model. The introduced model is easier to investigate analytically than the original inviscid Hasegawa-Mima model, as it has a nicer mathematical structure. The resemblance between this model and the Euler equations of inviscid incompressible fluids inspired us to adapt the techniques and ideas introduced for the two-dimensional and the three-dimensional Euler equations to prove the global existence and uniqueness of solutions for our model. Moreover, we prove the continuous dependence on initial data of solutions for the pseudo-Hasegawa-Mima model. These are the first results on existence and uniqueness of solutions for a model that is related to the three-dimensional inviscid Hasegawa-Mima equations