Breath-by-breath VCO2 and VO2 required compensation for transport delay and dynamic response

Both transport delay (DELAY) and dynamic response (RESPONSE) of a mass spectrometer would theoretically result in considerable errors in the breath-by-breath calculation of VCO2 and VO2. However, curiously, the contribution of RESPONSE has been ignored. The purpose of this study is to quantify the error caused by RESPONSE. We found that RESPONSE of a mass spectrometer was regarded as a first-order response. We determined DELAY and time constant (T) of RESPONSE and compensated the on-line calculation for both DELAY and RESPONSE and for DELAY only. With T of 150 and 100 ms, deviations of VCO2 from the gas-collection method were 8 +/- 6 and 8 +/- 6 ml/min with compensation for both DELAY and RESPONSE, and 69 +/- 10 and 50 +/- 5 ml/min with compensation for DELAY only, respectively (mean +/- SD). Similar results were obtained with VO2. A computer simulation of error caused by RESPONSE disclosed that the error linearly increased with increasing T. We conclude that to be accurate within +/- 5% of the exact value, compensation should be made when T exceeds 25 ms.

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On-Line Diagnosis of Do-Probe Condition in the Activated Sludge Process

Water Science & Technology ◽

10.2166/wst.1992.0750 ◽

1992 ◽

Vol 26 (9-11) ◽

pp. 2413-2416 ◽

Cited By ~ 2

Author(s):

H. Spanjers ◽

G. Olsson

Keyword(s):

Activated Sludge ◽

Time Constant ◽

Time Interval ◽

Aeration Tank ◽

Activated Sludge Process ◽

First Order ◽

On Line ◽

Do Concentration ◽

Probe Condition ◽

Probe Response

The dissolved oxygen (DO) probe is repeatedly subjected to a step change of the oxygen concentration with a time interval of 15-30 s. For this purpose an existing measuring technique was used in which the activated sludge was sampled continuously from the aeration tank. At each step the time constant of the probe response is estimated which provides a continuous diagnosis of the probe condition. Therefore the DO concentration measurements along the response are fitted to a first order response model of the probe. It was shown that the probe response time constant is a useful indicator for fouling of the probe membrane.

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Development and Application of A Membrane Inlet-Single Photon Ionization-Mass Spectrometer for On line Analysis Volatile Organic Compounds in Water

CHINESE JOURNAL OF ANALYTICAL CHEMISTRY (CHINESE VERSION) ◽

10.3724/sp.j.1096.2010.00760 ◽

2010 ◽

Vol 38 (5) ◽

pp. 760-764 ◽

Cited By ~ 1

Author(s):

Hua-Peng CUI ◽

Ke-Yong HOU ◽

Qing-Hao WU ◽

Lei HUA ◽

Ping CHEN ◽

...

Keyword(s):

Volatile Organic Compounds ◽

Organic Compounds ◽

Mass Spectrometer ◽

Single Photon ◽

Ionization Mass ◽

Single Photon Ionization ◽

Volatile Organic ◽

On Line ◽

Photon Ionization ◽

Line Analysis

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Submerged upflow biotower operation and computer simulation

Water Science & Technology ◽

10.2166/wst.1994.0554 ◽

1994 ◽

Vol 30 (11) ◽

pp. 143-146

Author(s):

Ronald D. Neufeld ◽

Christopher A. Badali ◽

Dennis Powers ◽

Christopher Carson

Keyword(s):

Computer Simulation ◽

Benzoic Acid ◽

Computer Model ◽

Rate Constants ◽

Batch Mode ◽

Operational Conditions ◽

First Order ◽

Low Concentrations ◽

Biological Transformation ◽

Kinetics Of

A two step operation is proposed for the biodegradation of low concentrations (< 10 mg/L) of BETX substances in an up flow submerged biotower configuration. Step 1 involves growth of a lush biofilm using benzoic acid in a batch mode. Step 2 involves a longer term biological transformation of BETX. Kinetics of biotransformations are modeled using first order assumptions, with rate constants being a function of benzoic acid dosages used in Step 1. A calibrated computer model is developed and presented to predict the degree of transformation and biomass level throughout the tower under a variety of inlet and design operational conditions.

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Parallel first-order Markov chain for on-line anomaly detection in traffic video surveillance

IET Conference on Crime and Security ◽

10.1049/ic:20060365 ◽

2006 ◽

Author(s):

F. Archetti ◽

C.E. Manfredotti ◽

M. Matteuci ◽

V. Messina ◽

D.G. Sorrenti

Keyword(s):

Markov Chain ◽

Anomaly Detection ◽

Video Surveillance ◽

First Order ◽

Order Markov Chain ◽

On Line ◽

Traffic Video

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14C AMS at Suerc: Improving QA Data with the 5MV Tandem and 250KV SSAMS

Radiocarbon ◽

10.1017/s003382220004529x ◽

2010 ◽

Vol 52 (2) ◽

pp. 263-271 ◽

Cited By ~ 27

Author(s):

P Naysmith ◽

G T Cook ◽

S P H T Freeman ◽

E M Scott ◽

R Anderson ◽

...

Keyword(s):

Quality Assurance ◽

Sample Preparation ◽

Mass Spectrometer ◽

Random Access ◽

Capacity Measurement ◽

Tandem Accelerator ◽

Standard Data ◽

Accelerator Mass Spectrometer ◽

On Line ◽

Automated Data Acquisition

In 2003, a National Electrostatics Corporation (NEC) 5MV tandem accelerator mass spectrometer was installed at SUERC, providing the radiocarbon laboratory with 14C measurements to 4–5‰ repeatability. In 2007, a 250kV single-stage accelerator mass spectrometer (SSAMS) was added to provide additional 14C capability and is now the preferred system for 14C analysis. Changes to the technology and to our operations are evident in our copious quality assurance data: typically, we now use the 134-position MC-SNICS source, which is filled to capacity. Measurement of standards shows that spectrometer running without the complication of on-line δ13C evaluation is a good operational compromise. Currently, 3‰ 14C/13C measurements are routinely achieved for samples up to nearly 3 half-lives old by consistent sample preparation and an automated data acquisition algorithm with sample random access for measurement repeats. Background and known-age standard data are presented for the period 2003–2008 for the 5MV system and 2007–2008 for the SSAMS, to demonstrate the improvements in data quality.

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