Experimental and Computational Analysis of the Heating Step during Thermoforming of Thermoplastics

2015 ◽  
Vol 651-653 ◽  
pp. 1003-1008 ◽  
Author(s):  
Bart Buffel ◽  
Marijke Amerijckx ◽  
Martijn Hamblok ◽  
Bart van Mieghem ◽  
Frederik Desplentere ◽  
...  
Keyword(s):  
Outer Surface ◽  
Infrared Radiation ◽  
Computational Analysis ◽  
Temperature Evolution ◽  
Temperature Relationship ◽  
High Quality ◽  
The Core ◽  
Hot Air ◽  
Radiative Power ◽  
Contact Free

The present study addresses the difficulties in heating thermoplastic sheets for ther-moforming applications. In industrial environments, the sheets are heated in a contact free method by means of convective hot air ovens and infrared radiation. In this study the temperature evolution at the outer surface as well as the core of thermoplastic sheets as a function of time is measured by means of thermocouples. These measurements reveal significant through thickness temperature dif-ferences which need to be resolved before high quality products can be made. The temperature dif-ferences can be decreased by decreasing the radiative power. This is however not acceptable in in-dustry since it lowers the number of produced parts per unit of time.In order to gain insight in the time-temperature relationship during the heating phase, a finite differ-ence model is developed. The model clearly shows the constantly changing through thickness tem-perature distribution and can be used as a tool by the thermoforming industry to optimize the pro-duction process.

A scanning electron microscopic study on dissolving process of cholesterol gallstones by chenodeoxycholic acid (CDCA)

1978 ◽  
Vol 36 (2) ◽  
pp. 522-523
Author(s):  
T. Kanetaka ◽  
M. Cho ◽  
S. Kawamura ◽  
T. Sado ◽  
K. Hara
Keyword(s):  
Electron Microscope ◽  
Chenodeoxycholic Acid ◽  
Outer Surface ◽  
Electron Microscopic ◽  
Cholesterol Gallstones ◽  
The Core ◽  
Scanning Electron Microscopic Study ◽  
Scanning Electron Microscopic ◽  
Acceleration Voltage ◽  
Scanning Electron

The authors have investigated the dissolution process of human cholesterol gallstones using a scanning electron microscope(SEM). This study was carried out by comparing control gallstones incubated in beagle bile with gallstones obtained from patients who were treated with chenodeoxycholic acid(CDCA).The cholesterol gallstones for this study were obtained from 14 patients. Three control patients were treated without CDCA and eleven patients were treated with CDCA 300-600 mg/day for periods ranging from four to twenty five months. It was confirmed through chemical analysis that these gallstones contained more than 80% cholesterol in both the outer surface and the core.The specimen were obtained from the outer surface and the core of the gallstones. Each specimen was attached to alminum sheet and coated with carbon to 100Å thickness. The SEM observation was made by Hitachi S-550 with 20 kV acceleration voltage and with 60-20, 000X magnification.

scholarly journals Evaluating the accuracy of Listeria monocytogenes assemblies from quasimetagenomic samples using long and short reads

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Seth Commichaux ◽  
Kiran Javkar ◽  
Padmini Ramachandran ◽  
Niranjan Nagarajan ◽  
Denis Bertrand ◽  
...  
Keyword(s):  
Public Health ◽  
Public Health Response ◽  
High Quality ◽  
Short Read ◽  
Short Reads ◽  
The Core ◽  
Long Reads ◽  
Health Response ◽  
Long Read ◽  
Core Genes

Abstract Background Whole genome sequencing of cultured pathogens is the state of the art public health response for the bioinformatic source tracking of illness outbreaks. Quasimetagenomics can substantially reduce the amount of culturing needed before a high quality genome can be recovered. Highly accurate short read data is analyzed for single nucleotide polymorphisms and multi-locus sequence types to differentiate strains but cannot span many genomic repeats, resulting in highly fragmented assemblies. Long reads can span repeats, resulting in much more contiguous assemblies, but have lower accuracy than short reads. Results We evaluated the accuracy of Listeria monocytogenes assemblies from enrichments (quasimetagenomes) of naturally-contaminated ice cream using long read (Oxford Nanopore) and short read (Illumina) sequencing data. Accuracy of ten assembly approaches, over a range of sequencing depths, was evaluated by comparing sequence similarity of genes in assemblies to a complete reference genome. Long read assemblies reconstructed a circularized genome as well as a 71 kbp plasmid after 24 h of enrichment; however, high error rates prevented high fidelity gene assembly, even at 150X depth of coverage. Short read assemblies accurately reconstructed the core genes after 28 h of enrichment but produced highly fragmented genomes. Hybrid approaches demonstrated promising results but had biases based upon the initial assembly strategy. Short read assemblies scaffolded with long reads accurately assembled the core genes after just 24 h of enrichment, but were highly fragmented. Long read assemblies polished with short reads reconstructed a circularized genome and plasmid and assembled all the genes after 24 h enrichment but with less fidelity for the core genes than the short read assemblies. Conclusion The integration of long and short read sequencing of quasimetagenomes expedited the reconstruction of a high quality pathogen genome compared to either platform alone. A new and more complete level of information about genome structure, gene order and mobile elements can be added to the public health response by incorporating long read analyses with the standard short read WGS outbreak response.

scholarly journals A High Rigidity and Precision Scanning Tunneling Microscope with Decoupled XY and Z Scans

Scanning ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Xu Chen ◽  
Tengfei Guo ◽  
Yubin Hou ◽  
Jing Zhang ◽  
Wenjie Meng ◽  
...  
Keyword(s):  
Scanning Tunneling Microscope ◽  
Atomic Resolution ◽  
Scanning Tunneling ◽  
Electronic Noise ◽  
High Quality ◽  
Tunneling Microscope ◽  
The Core ◽  
High Rigidity ◽  
The Common ◽  
The Impact

A new scan-head structure for the scanning tunneling microscope (STM) is proposed, featuring high scan precision and rigidity. The core structure consists of a piezoelectric tube scanner of quadrant type (for XY scans) coaxially housed in a piezoelectric tube with single inner and outer electrodes (for Z scan). They are fixed at one end (called common end). A hollow tantalum shaft is coaxially housed in the XY-scan tube and they are mutually fixed at both ends. When the XY scanner scans, its free end will bring the shaft to scan and the tip which is coaxially inserted in the shaft at the common end will scan a smaller area if the tip protrudes short enough from the common end. The decoupled XY and Z scans are desired for less image distortion and the mechanically reduced scan range has the superiority of reducing the impact of the background electronic noise on the scanner and enhancing the tip positioning precision. High quality atomic resolution images are also shown.

scholarly journals The Molding Influence

1999 ◽  
Vol 121 (10) ◽  
pp. 70-72
Author(s):  
Hutchinson Harry
Keyword(s):  
Design Process ◽  
Cad Model ◽  
Test Program ◽  
High Quality ◽  
The Core ◽  
The One ◽  
Beta Testing ◽  
Standard Components ◽  
Beta Test

This article presents study that shows beta testing shapes software to the users’ hands so the product will fit the marketplace. MoldWizard is intended to reduce the time necessary to design complex mold tooling, such as this mold used to manufacture the plastic housings for high-quality nail guns. Depending on the complexity of a mold and its eventual use, the design process can require as many as 50 different steps, including tasks such as importing and cleaning up the CAD model of the part, adjusting its size for shrinkage, separating the core and cavity, generating mold bases, and adding sliders, inserts, and other standard components. Minco Tool & Mold uses Unigraphics to design molds like the one shown in the article for an automobile hubcap. Minco participated in the MoldWizard beta test program. A news group at the website let the test users communicate directly with each other. When beta testers had questions about how to use the program, they posted them in the news group and other testers would respond.

Different Strategies of Far-Infrared Radiation Application in Paddy Drying

2008 ◽  
Vol 4 (3) ◽  
Author(s):  
Naret Meeso ◽  
Adisak Nathakaranakule ◽  
Thanid Madhiyanon ◽  
Somchart Soponronnarit
Keyword(s):  
Infrared Radiation ◽  
Far Infrared ◽  
Ambient Air ◽  
Average Moisture Content ◽  
Drying Process ◽  
Milling Quality ◽  
Hot Air ◽  
Air Ventilation ◽  
Fluidized Bed Drying ◽  
Far Infrared Radiation

The applied strategy of far-infrared radiation in paddy drying is divided into two main processes with some overlapping, namely, series and combined drying processes. The first comprises fluidized-bed drying, far-infrared radiation, tempering and ambient air ventilation as well as transport of paddy, and the latter is the combination of far-infrared radiation and hot-air convection in fluidization technique. The changes of average moisture content, grain temperature and milling quality in each paddy drying process are presented together with mathematical models. The experiments showed that series drying process was more effective to apply in the aspects of paddy drying and milling qualities than combined drying process. Due to less effectiveness in combined drying process, heat and mass transfer models, only series drying process were developed. The simulation results indicated that the models were capable of satisfactorily predicting the simultaneous average moisture contents and grain temperatures of a paddy grain as compared with the experimental results.

Mesoamerican Polyhedral Cores and Prismatic Blades

1968 ◽  
Vol 33 (4) ◽  
pp. 446-478 ◽  
Author(s):  
Don E. Crabtree
Keyword(s):  
High Speed ◽  
Large Series ◽  
High Speed Photography ◽  
High Quality ◽  
Pressure Method ◽  
The Core ◽  
Quality Material ◽  
Muscular Coordination

AbstractThis paper deals with the results of the author"s attempts to replicate the obsidian polyhedral cores and prismatic blades of Mesoamerica. Blades have been produced by the direct percussion, indirect percussion, and pressure methods. The pressure method using a chest crutch and a clamp produces cores and blades which are true replicas of aboriginal specimens. The importance of preforming the core and of platform preparation is stressed, and it is pointed out that, usually, actual removal of the blade offers few problems. However, to produce exhausted cores which show the perfection of aboriginal specimens and a large series of nearly identical blades requires good muscular coordination, high quality material, the establishment of patterns or rhythms of motor habits, and the absence of distractions. The author also discusses the difficulties of recovering from mistakes in manufacture.High-speed photography of prismatic blade removal, at 5,000 frames per second, has helped illustrate the behavior of the material and of the stoneworker. These photographs also indicate that under the present experimental and photographic conditions the author (Crabtree) is able to remove a prismatic blade from a core in about 1,250th of a second.

Integrated Analysis of Mechanical and Thermal Hydraulic Behavior of Graphite Stack in Channel-Type Reactors in Case of a Fuel Channel Rupture Accident

2002 ◽  
Author(s):  
Sergei L. Soloviev ◽  
Boris A. Gabaraev ◽  
Leonid M. Parafilo ◽  
Dmitry V. Kruchkov ◽  
Oleg Yu. Novoselsky ◽  
...  
Keyword(s):  
Computational Analysis ◽  
Pressure Tube ◽  
Integrated Analysis ◽  
The Core ◽  
Pressure Tubes ◽  
Confinement System ◽  
Integrated Code ◽  
Channel Type ◽  
Graphite Stack ◽  
Fluid Parameters

The paper discusses the methodology and a computational exercise analyzing the processes taking place in the graphite stack of an RBMK reactor in case of a pressure tube rupture caused by overheating. The methodology of the computational analysis is implemented in integrated code U_STACK which models thermal-hydraulic and mechanical processes in the stack with a varying geometry, coupled with the processes going on in the circulation loop and accident localization (confinement) system. Coolant parameters, cladding and pressure tube temperatures, pressure tube ballooning and rupture, coolant outflow are calculated for a given accident scenario. Fluid parameters, movement of graphite blocks and adjacent pressure tubes bending after the tube rupture are calculated for the whole volume of the core. Calculations also cover additional loads on adjacent fuel channels in the rupture zone, reactor shell, upper and lower plates. Impossibility of an induced pressure tube rupture is confirmed.

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