736 research outputs found
Visual environment for editing and solving flowsheets : design and implementation of a visual environment for editing and solving flowsheets to produce heat and material balances for urea plant designs
Urea is an organic compound that is used widely as a fertilizer to increase the crop size and the yield. Urea is produced from ammonia and carbon dioxide in urea plants. Stamicarbon’s main activity is designing and licensing urea plants. An important activity of the process engineers at Stamicarbon consists of the design of the flowsheet and the calculation of the solution of the heat and material balances for the urea plant. Improving the productivity of the process engineers and shortening the learning curve of the new process engineers is of great importance to Stamicarbon. Stamicarbon’s vision is to the change the flowsheet design from text-based to graphics-based. This project aimed to implement a graphics-based solution that would increase the comprehension of the structure and the state of the flow-sheet design. This project also aimed to enable the process engineers to visually merge plant sections that could be reused in flowsheet designs. Finally, a part of this project involved the integration of the graphics-based editor and the flowsheet solver into one tool. The three major design criteria are usability, navigability, and extensibility. The main tools used for the implementation of this project are the Eclipse Modeling Framework (EMF) and the Eclipse Sirius. The domain model is designed with EMF. The visual representations are created with Eclipse Sirius. The architecture of the system is plug-in based. The final prototype is deployed as an RCP outside the Eclipse IDE
Visual environment for editing and solving flowsheets : design and implementation of a visual environment for editing and solving flowsheets to produce heat and material balances for urea plant designs
Urea is an organic compound that is used widely as a fertilizer to increase the crop size and the yield. Urea is produced from ammonia and carbon dioxide in urea plants. Stamicarbon’s main activity is designing and licensing urea plants. An important activity of the process engineers at Stamicarbon consists of the design of the flowsheet and the calculation of the solution of the heat and material balances for the urea plant. Improving the productivity of the process engineers and shortening the learning curve of the new process engineers is of great importance to Stamicarbon. Stamicarbon’s vision is to the change the flowsheet design from text-based to graphics-based. This project aimed to implement a graphics-based solution that would increase the comprehension of the structure and the state of the flow-sheet design. This project also aimed to enable the process engineers to visually merge plant sections that could be reused in flowsheet designs. Finally, a part of this project involved the integration of the graphics-based editor and the flowsheet solver into one tool. The three major design criteria are usability, navigability, and extensibility. The main tools used for the implementation of this project are the Eclipse Modeling Framework (EMF) and the Eclipse Sirius. The domain model is designed with EMF. The visual representations are created with Eclipse Sirius. The architecture of the system is plug-in based. The final prototype is deployed as an RCP outside the Eclipse IDE
3D Printing Provides a Precise Approach in the Treatment of Tetralogy of Fallot, Pulmonary Atresia with Major Aortopulmonary Collateral Arteries.
Patients with tetralogy of Fallot, pulmonary atresia, and multiple aortopulmonary collateral arteries (Tet PA MAPCAs) have a wide spectrum of anatomy and disease severity. Management of these patients can be challenging and often require multiple high-risk surgical and interventional catheterization procedures. These interventions are made challenging by complex anatomy that require the proceduralist to mentally reconstruct three-dimensional anatomic relationships from two-dimensional images. Three-dimensional (3D) printing is an emerging medical technology that provides added benefits in the management of patients with Tet PA MAPCAs. When used in combination with current diagnostic modalities and procedures, 3D printing provides a precise approach to the management of these challenging, high-risk patients. Specifically, 3D printing enables detailed surgical and interventional planning prior to the procedure, which may improve procedural outcomes, decrease complications, and reduce procedure-related radiation dose and contrast load
A method for solving systems of non-linear differential equations with moving singularities
We present a method for solving a class of initial valued, coupled,
non-linear differential equations with `moving singularities' subject to some
subsidiary conditions. We show that this type of singularities can be
adequately treated by establishing certain `moving' jump conditions across
them. We show how a first integral of the differential equations, if available,
can also be used for checking the accuracy of the numerical solution.Comment: 9 pages, 7 eps figures, to appear in Comput. Phys. Co
Gut dysfunction in patients with multiple sclerosis and the role of spinal cord involvement in the disease.
Bowel and bladder symptoms are highly prevalent in patients with multiple sclerosis (MS). Bladder dysfunction (affecting 75% of these patients) is caused by disease in the spinal cord, whilst the pathophysiology of bowel dysfunction is unknown. Pathways regulating both the organs lie in close proximity to the spinal cord, and coexistence of their dysfunction might be the result of a common pathophysiology. If so, the prevalence of bladder symptoms should be greater in patients with MS and bowel symptoms. This hypothesis is tested in the study. We also evaluated how patient-reported symptoms quantify bowel dysfunction
Impact of a single nucleotide polymorphism on the 3D protein structure and ubiquitination activity of E3 ubiquitin ligase arkadia
Single nucleotide polymorphisms (SNPs) are genetic variations which can play a vital role in the study of human health. SNP studies are often used to identify point mutations that are associated with diseases. Arkadia (RNF111) is an E3 ubiquitin ligase that enhances transforming growth factor-beta (TGF-β) signaling by targeting negative regulators for degradation. Dysregulation of the TGF-β pathway is implicated in cancer because it exhibits tumor suppressive activity in normal cells while in tumor cells it promotes invasiveness and metastasis. Τhe SNP CGT > TGT generated an amino-acid (aa) substitution of Arginine 957 to Cysteine on the enzymatic RING domain of Arkadia. This was more prevalent in a tumor than in a normal tissue sample of a patient with colorectal cancer. This prompted us to investigate the effect of this mutation in the structure and activity of Arkadia RING. We used nuclear magnetic resonance (NMR) to analyze at an atomic-level the structural and dynamic properties of the R957C Arkadia RING domain, while ubiquitination and luciferase assays provided information about its enzymatic functionality. Our study showed that the R957C mutation changed the electrostatic properties of the RING domain however, without significant effects on the structure of its core region. However, the functional studies revealed that the R957C Arkadia exhibits significantly increased enzymatic activity supporting literature data that Arkadia within tumor cells promotes aggressive and metastatic behavior
Monitoring dust particle orientation with measurements of sunlight dichroic extinction
© 2021 COMECAP CONFERENCE. All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means, electronic, mechanical, photocopying or otherwise, without the prior written permission of the author.Alignment of irregularly shaped dust aerosols leading to linear dichroism has been reported in atmospheric layers. The present study intents to quantify the excess linear polarization of direct solar radiation propagating through atmospheric layers, when these contain oriented dust particles. In order to record the linear polarization, we have used the Solar Polarimeter (SolPol). SolPol is an instrument that measures the polarization of direct solar irradiance at 550nm. It is installed on an astronomical tracker in order target the solar disk. Using the measurements, the Stokes parameters are retrieved (I, Q/I, U/I and V/I) with an accuracy of ~1% and precision of 1 ppm. Collocated measurements of a sun-photometer (Aerosol Robotic Network; AERONET) and lidar are used to quantify the Aerosol Optical Depth (AOD) and identify the vertical distribution of dust layers, respectively. We will present indications of dust particle orientation recorded at the PANGEA station in the island of Antikythera, Greece, and at Nicosia, Cyprus during the preparatory phase for the ASKOS campaign in July 2021. The relation of the linear polarization of the solar irradiance to other optical properties of the dust layer is investigated
rac-5-Acetyl-6-hyÂdroxy-3,6-dimethyl-4-phenyl-2H-4,5,6,7-tetraÂhydroÂindazol-1-ium chloride
The structure of the title compound, C17H21N2O2
+·Cl−, is of interÂest with respect to its biological activity. The title compound comprises an organic cation and a chloride anion in the asymmetric unit. The positive charge is localized in a pyrazole moiety forming a pyrazolium cation. The structure displays interÂmolecular O—H⋯Cl and N—H⋯Cl hydrogen bonding
Hybrid integration of microfabricated chemοcapacitor arrays with miniaturized read-out electronics towards low-power gas sensing module
AbstractA hybrid gas sensing module consisting of an array of 8 polymer coated capacitive sensors and low power read-out electronics is introduced. The chemocapacitor array is fabricated with standard microelectronics/micromachining processes allowing for the realization of planar InterDigitated Electrodes (IDEs). The read-out electronics sub- module consists of an analog multiplexer for the sequential measurement of the sensor array elements, a capacitance to 24-bit converter and a USB to I2C interface. The compact hybrid module has been successfully applied in the detection of sub-100ppm concentrations of p-xylene and toluene. The responses to various humidity levels have been also evaluated
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