scholarly journals The Quaternary Isotope Laboratory Thermal Diffusion Enrichment System: Description and Performance

Radiocarbon ◽  
1979 ◽  
Vol 21 (2) ◽  
pp. 139-164 ◽  
Author(s):  
Pieter M Grootes ◽  
Minze Stuiver

The thermal diffusion enrichment system of the Quaternary Isotope Laboratory consists of 23 hot wire columns of 3m effective length combined to 2 separate systems of 3 and 3 separate systems of 4 columns at the top, each system in series with 1 bottom column. From ≈ 130 L NTP of CO (∼ 65g of carbon) it produces ≈ 8 L NTP of CO (~ 4g of carbon) enriched in12C18O by a factor 6 to 7 and in14C16O by a factor 7 to 8 in about 5 weeks. For12C18O the system has a theoretical equilibrium separation factor of about 250 and a theoretical equilibrium enrichment of about 15. For14C16O these values are 1300 and 16, respectively. The dependence of thermal diffusion transport on gas exchange between top and bottom section and between columns and reservoirs and on wire temperature is given. Forced gas exchange and a higher wire temperature gave a more rapidly increasing enrichment without substantially increasing its final value of 6 to 7 for12C18O. A comparison with the Groningen enrichment system shows that the two systems behave very similarly and that not the system geometry but individual column parameters and the ratio total sample mass/enriched sample mass are the dominant factors determining the enrichment.

Author(s):  
Matthew Westin ◽  
Ronald Dougherty ◽  
Christopher Depcik ◽  
Austin Hausmann ◽  
Charles Sprouse

The original use of the vehicle dashboard was to provide enough sensory information to inform the driver of the current engine and vehicle status and performance. Over time, it has evolved into an entertainment system that includes person-to-person communication, global positioning information, and the Internet, just to name a few. Each of these new features adds to the amount of information that drivers must absorb, leading to potential distraction and possible increases in the number and types of accidents. In order to provide an overview of these issues, this paper summarizes previous work on driver distraction and workload, demonstrating the importance of addressing those issues that compete for driver attention and action. In addition, a test platform vehicle is introduced which has the capability of assessing modified dashboards and consoles, as well as the ability to acquire relevant driving performance data. Future efforts with this test platform will be directed toward helping to resolve the critical tug-of-war between providing more information and entertainment while keeping drivers and their passengers safe. The long-term goal of this research is to evaluate the various technological innovations available for inclusion in the driving environment and determining how to optimize driver information delivery without excessive distraction and workload. The information presented herein is the first step in that effort of developing an adaptive distraction/workload management system that monitors performance metrics and provides selected feedback to drivers. The test platform (1973 VW Beetle converted to a plug-in series hybrid) can provide speed, location (GPS), 3-D acceleration, and rear proximity detection. The test drive route was a 2 km × 3 km city street circuit which took approximately 25 minutes to complete. Data is provided herein to demonstrate these capabilities. In addition, the platform has driver selectable layouts for the instrument cluster and console (LCD screens). The test platform is planned for use to determine driver preferences (e.g., dashboard/console configurations) and attention performance in addition to identifying optimal real-time feedback for drivers with different demographics.


2008 ◽  
Vol 5 (6) ◽  
pp. 568-573 ◽  
Author(s):  
Yaohui Zhang ◽  
Jiang Liu ◽  
Juan Yin ◽  
Wensheng Yuan ◽  
Jing Sui

1995 ◽  
Vol 17 (6) ◽  
pp. 205-212 ◽  
Author(s):  
Stuart W. Gibb ◽  
John W. Wood ◽  
R. Fauzi ◽  
C. Mantoura

The automation and improved design and performance of Flow Injection Gas Diffusion-Ion Chromatography (FIGD-IC), a novel technique for the simultaneous analysis of trace ammonia (NH3) and methylamines (MAs) in aqueous media, is presented. Automated Flow Injection Gas Diffusion (FIGD) promotes the selective transmembrane diffusion of MAs and NH3from aqueous sample under strongly alkaline (pH > 12, NaOH), chelated (EDTA) conditions into a recycled acidic acceptor stream. The acceptor is then injected onto an ion chromatograph where NH3and the MAs are fully resolved as their cations and detected conductimetrically. A versatile PC interfaced control unit and data capture unit (DCU) are employed in series to direct the selonoid valve switching sequence, IC operation and collection of data. Automation, together with other modifications improved both linearily (R2> 0.99 MAs 0-100 nM, NH30-1000 nM) and precision (<8%) of FIGD-IC at nanomolar concentrations, compared with the manual procedure. The system was successfully applied to the determination of MAs and NH3in seawater and in trapped particulate and gaseous atmospheric samples during an oceanographic research cruise.


2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Takahiko Tsujisawa ◽  
Kazuhiro Yamakawa

We propose a sensor consisting of small-sized coils connected in series and a detection method for the sensor based on the iteration of the periodic time difference. The evaluation results are also presented and show the effectiveness of the proposed system. The target performance of the sensor is as follows: (i) a detection range from 0 to ±100 Nm, (ii) a hysteresis error of less than 1%, (iii) an angular-dependent noise of less than 2%, and (iv) a sensor drift of less than 2%. From the evaluation results, it is clear that these performance targets, as well as a sufficient response time, are realized.


2010 ◽  
Vol 18 (3) ◽  
Author(s):  
A. Rogalski

AbstractIn Poland, the HgCdTe studies began in 1960 at the Institute of Physics, Warsaw University. The material processing laboratory was created by Giriat and later by Dziuba, Gałązka, and others. Bridgman technique with sealed thick wall quartz ampoules was used to grow material suitable for research and experimental devices. Among the first papers published in 1961 and 1963 there were the Polish works devoted to preparation, doping, and electrical properties of HgCdTe.Infrared detector’s research and development efforts in Poland were concentrated mostly on uncooled market niche. At the beginning, a modified isothermal vapour phase epitaxy has been used for research and commercial fabrication of photoconductive, photoelectromagnetic and other HgCdTe devices. Bulk growth and liquid phase epitaxy were also used. Recently, the fabrication of infrared devices relies on low temperature epitaxial technique, namely metalorganic vapour phase deposition.At present stage of development, the photoconductive and photoelectromagnetic (PEM) detectors are gradually replaced with photovoltaic devices which offer inherent advantages of no electric or magnetic bias, no heat load and no flicker noise. Potentially, photodiodes offer high performance and very fast response. However, conventional photovoltaic uncooled detectors suffer from low quantum efficiency and very low junction resistance. The problems have been solved with advanced band gap engineered architecture, multiple cell heterojunction devices connected in series, and monolithic integration of the detectors with microoptics.In final part of the paper, the Polish achievements in technology and performance of HgMnTe and HgZnTe photodetectors are presented.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hamed Eghbalahmadi ◽  
Parissa Khadiv-Parsi ◽  
Seyed Mohammad Ali Mousavian ◽  
Mohammad Hosein Eghbal Ahmadi

Abstract In this study, numerical simulations were carried out to investigate the separation of the helium-argon gas mixture by thermal diffusion column. This research determined the significant parameters and their effects on the process performance. Effects of feed flow rate, cut ratio, and hot wire temperature in a 950 mm height column with an inner tube of 9.5 mm radius were examined through the simulation of the thermal diffusion column. For minimizing the number of simulations and obtaining the optimum operating conditions, response surface methodology (RSM) was used. Analysis of separative work unit (SWU) values as a target function for helium-argon separation clearly showed that the maximum amount of SWU in thermal diffusion column was achieved, when hot wire temperature increased as large as technically possible, and the feed rate and cut ratio were equal to 55 Standard Cubic Centimeters per Minute (SCCM) and 0.44, respectively. Finally, the SWU value in optimum conditions was compared with the experimental data. Results illustrated that the experimental data were in good agreement with simulation data with an accuracy of about 90%.


Radiocarbon ◽  
1995 ◽  
Vol 37 (2) ◽  
pp. 649-656 ◽  
Author(s):  
Andreas Gottdang ◽  
Dirk J. W. Mous ◽  
Johannes Van Der Plicht

Since May 1994, a new-generation accelerator mass spectrometer (AMS) has been fully operational at the Centre for Isotope Research in Groningen, The Netherlands. The fully automated and high-throughput accelerator mass spectrometry (AMS) system, manufactured by High Voltage Engineering Europa (HVEE) is dedicated to radiocarbon analysis. The HVEE 4130 14C AMS is able to analyze up to 3000 samples per year. The system is characterized by simultaneous transport of all three isotopes (12C, 13C, 14C) and 14C analysis with a precision below 0.5 pMC and a daily stability below 0.5 pMC. We present here a system description together with stability and performance measurements.


2015 ◽  
Vol 785 ◽  
pp. 611-615
Author(s):  
Nuril Yaqin Ab Rahim ◽  
Shahril Irwan Sulaiman ◽  
Zulkifli Othman

This paper presents sizing software for the design of a solar farm system. The sizing software provides few guidelines to the designer for the planning procedure before the final of optimum array configuration is decided. Some specifications that the designer may consider are the type of PV module, the type of inverter, the available space for installation, the required energy per year and also the sum of money to be allocated for the instalment. The output result of this software will be the suggestion of possible configuration of the total number of modules in series per string with the total number of strings in parallel. This software also does the prediction of the system performances such as final yield, specific yield and performance ratio. The expected income is provided by the software is based on the Feed-in Tariff rates and the energy generated by the system.


2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Xiling Xie ◽  
Mingke Ren ◽  
Zhiyi Zhang

Abstract An adaptive method for suppressing mechanical vibration of multiple frequencies is investigated. The adaptive controller is reinforced with saturation alleviator to improve the convergence rate and performance of the adaptive algorithm. Tracking filters are used to extract harmonics of fluctuating frequencies and the anti-saturation unit works in series with the tracking filters to give constrained harmonic output. As a result, the controller is insensitive to abnormally large input that would otherwise induce saturation in actuators. A dynamic model is built for vibration suppression simulation and the numerical results indicate that the adaptive algorithm is effective in cases of multiple fluctuating frequencies and output saturation. Experiments were also conducted to test the performance of the adaptive method. Excitation with oscillating frequencies was applied, and the results have demonstrated that the harmonics can be suppressed effectively with the adaptive method.


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