scholarly journals Representative Sampling Implementation in Online VFA/TIC Monitoring for Anaerobic Digestion

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1179
Author(s):  
Camilo Wilches ◽  
Maik Vaske ◽  
Kilian Hartmann ◽  
Michael Nelles
Keyword(s):  
Human Error ◽  
Sampling Errors ◽  
Sampling System ◽  
Representative Sampling ◽  
Anaerobic Reactors ◽  
Biogas Plants ◽  
Theory Of Sampling ◽  
Online Monitoring System ◽  
Analysis Error ◽  
Representative Samples

This paper describes an automatic sampling system for anaerobic reactors that allows taking representative samples following the guidelines of Gy’s (1998) theory of sampling. Due to the high heterogeneity degree in a digester the sampling errors are larger than the analysis error, making representative sampling a prerequisite for successful process control. In our system, samples are automatically processed, generating a higher density of data and avoiding human error by sample manipulation. The combination of a representative sampling system with a commercial automate titration unit generates a robust online monitoring system for biogas plants. The system was successfully implemented in an operating biogas plant to control a feeding-on-demand biogas system.

scholarly journals Integrating the Theory of Sampling into Underground Mine Grade Control Strategies: Case Studies from Gold Operations

Minerals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 238
Author(s):  
Dominy ◽  
Glass ◽  
O’Connor ◽  
Lam ◽  
Purevgerel
Keyword(s):  
Case Studies ◽  
Control Strategies ◽  
Control Process ◽  
Control Programme ◽  
Small Scale ◽  
Sampling Errors ◽  
Sample Collection ◽  
Representative Sampling ◽  
Grade Control ◽  
Theory Of Sampling

Grade control aims to deliver adequately defined tonnes of ore to the process plant. The foundation of any grade control programme is collecting high-quality samples within a geological context. The requirement for quality samples has long been recognised, in that these should be representative and fit-for-purpose. Correct application of the Theory of Sampling reduces sampling errors across the grade control process, in which errors can propagate from sample collection through sample preparation to assay results. This contribution presents three case studies which are based on coarse gold-dominated orebodies. These illustrate the challenges and potential solutions to achieve representative sampling and build on the content of a previous publication. Solutions ranging from bulk samples processed through a plant to whole-core sampling and assaying using bulk leaching, are discussed. These approaches account for the nature of the mineralisation, where extreme gold particle-clustering effects render the analysis of small-scale samples highly unrepresentative. Furthermore, the analysis of chip samples, which generally yield a positive bias due to over-sampling of quartz vein material, is discussed.

scholarly journals A Reliable Automated Sampling System for On-Line and Real-Time Monitoring of CHO Cultures

Processes ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 637
Author(s):  
Alexandra Hofer ◽  
Paul Kroll ◽  
Matthias Barmettler ◽  
Christoph Herwig
Keyword(s):  
Measurement Errors ◽  
Human Error ◽  
Current Trend ◽  
Sampling Procedure ◽  
Sensor Technology ◽  
Monitoring And Control ◽  
Sampling System ◽  
Advantages And Disadvantages ◽  
On Line ◽  
Automated Sampling

Timely monitoring and control of critical process parameters and product attributes are still the basic tasks in bioprocess development. The current trend of automation and digitization in bioprocess technology targets an improvement of these tasks by reducing human error and increasing through-put. The gaps in such automation procedures are still the sampling procedure, sample preparation, sample transfer to analyzers, and the alignment of process and sample data. In this study, an automated sampling system and the respective data management software were evaluated for system performance; applicability with HPLC for measurement of vitamins, product and amino acids; and applicability with a biochemical analyzer. The focus was especially directed towards the adaptation and assessment of an appropriate amino acid method, as these substances are critical in cell culture processes. Application of automated sampling in a CHO fed-batch revealed its potential with regard to data evaluation. The higher sampling frequency compared to manual sampling increases the generated information content, which allows easier interpretation of the metabolism, extraction of e.g., ks values, application of smoothing algorithms, and more accurate detection of process events. A comparison with sensor technology shows the advantages and disadvantages in terms of measurement errors and measurement frequency.

scholarly journals Design and Field Campaign Validation of a Multirotor UAV and Optical Particle Counter

2020 ◽  
Author(s):  
Joseph Girdwood ◽  
Helen Smith ◽  
Warren Stanley ◽  
Zbigniew Ulanowski ◽  
Chris Stopford ◽  
...  
Keyword(s):  
Low Cost ◽  
Unmanned Aircraft ◽  
Coefficient Of Determination ◽  
Sampling System ◽  
Particle Counter ◽  
Representative Sampling ◽  
Atmospheric Particulates ◽  
Optical Particle Counter ◽  
Good Agreement

Abstract. Small unmanned aircraft (SUA) have the potential to be used as platforms for the measurement of atmospheric particulates. The use of an SUA platform for these measurements provides benefits such as high manoeuvrability, re-usability, and low-cost when compared with traditional techniques. However, the complex aerodynamics of an SUA (particularly for multirotor airframes), combined with the miniaturisation of particle instruments poses difficulties for accurate and representative sampling of particulates. The work presented here relies on computational fluid dynamics with Lagrangian particle tracking (CFD-LPT) simulations to influence the design of a bespoke meteorological sampling system: the UH-AeroSAM. This consists of a custom built airframe, designed to reduce sampling artefacts due to the propellers, and a purpose built open-path optical particle counter–the Ruggedised Cloud and Aerosol Sounding System (RCASS). OPC size distribution measurements from the UH-AeroSAM are compared with the Cloud and Aerosol Precipitation Spectrometer (CAPS) for measurements of Stratus cloud during the Pallas Cloud Experiment (PaCE) in 2019. Good agreement is demonstrated between the two instruments. The integrated dN/dlog(Dp) is shown to have a coefficient of determination of 0.8, and a regression slope of 0.9 when plotted 1:1.

scholarly journals Design and field campaign validation of a multi-rotor unmanned aerial vehicle and optical particle counter

2020 ◽  
Vol 13 (12) ◽  
pp. 6613-6630
Author(s):  
Joseph Girdwood ◽  
Helen Smith ◽  
Warren Stanley ◽  
Zbigniew Ulanowski ◽  
Chris Stopford ◽  
...  
Keyword(s):  
Low Cost ◽  
Unmanned Aircraft ◽  
Coefficient Of Determination ◽  
Sampling System ◽  
Particle Counter ◽  
Representative Sampling ◽  
Atmospheric Particulates ◽  
Optical Particle Counter ◽  
Aerial Vehicle ◽  
Glass Optics

Abstract. Small unmanned aircraft (SUA) have the potential to be used as platforms for the measurement of atmospheric particulates. The use of an SUA platform for these measurements provides benefits such as high manoeuvrability, reusability, and low cost when compared with traditional techniques. However, the complex aerodynamics of an SUA – particularly for multi-rotor airframes – pose difficulties for accurate and representative sampling of particulates. The use of a miniaturised, lightweight optical particle instrument also presents reliability problems since most optical components in a lightweight system (for example laser diodes, plastic optics, and photodiodes) are less stable than their larger, heavier, and more expensive equivalents (temperature-regulated lasers, glass optics, and photomultiplier tubes). The work presented here relies on computational fluid dynamics with Lagrangian particle tracking (CFD–LPT) simulations to influence the design of a bespoke meteorological sampling system: the UH-AeroSAM. This consists of a custom-built airframe, designed to reduce sampling artefacts due to the propellers, and a purpose-built open-path optical particle counter (OPC) – the Ruggedised Cloud and Aerosol Sounding System (RCASS). OPC size distribution measurements from the UH-AeroSAM are compared with the cloud, aerosol, and precipitation spectrometer (CAPS) for measurements of stratus clouds during the Pallas Cloud Experiment (PaCE) in 2019. Good agreement is demonstrated between the two instruments. The integrated dN∕dlog (Dp) is shown to have a coefficient of determination of 0.8 and a regression slope of 0.9 when plotted 1:1.

Recommendations Concerning Materials and Pumping Systems Used in the Sampling of Groundwater Contaminated with Volatile Organics

1987 ◽  
Vol 22 (1) ◽  
pp. 65-72 ◽  
Author(s):  
J.F. Devlin
Keyword(s):  
Field Tests ◽  
Field Studies ◽  
Sample Collection ◽  
Volatile Organics ◽  
Sampling System ◽  
Positive Displacement ◽  
Groundwater Samples ◽  
Teflon Tubing ◽  
Polyethylene Tubing ◽  
Representative Samples

Abstract Laboratory and field studies were performed at the River Road Laboratories of Environment Canada, to evaluate the effect of storage containers, tubing material and pumping method on the integrity of groundwater samples contaminated with volatile organics. The work was aimed at establishing a sampling protocol which can be easily adapted to a variety of field situations and which preserves sample integrity at every stage from collection to analysis. In the laboratory, storability studies were conducted on prepared samples containing a suite of 15 volatile aliphatic, halogenated aliphatic and aromatic compounds, in both glass vials and in Tedlar bags developed during the project. Glass was found to be the preferred container for the storability of samples. Leaching studies were carried out on both Teflon and polyethylene tubing (100 ft., 0.2″ i.d.); neither material was found to substantially contaminate organic-free deionized water. Sorption studies conducted on the same tubing sample 9 indicated that polyethylene sorbs the organics to a substantially greater degree than Teflon. However, representative samples can be obtained through both tubing materials provided that a flushing procedure is followed prior to sample collection. In the field, tests were carried out to determine if sampling into glass vials (significant sample/air contact during collection) introduces any bias to prepared standards. The results suggest that a closed sampling system is preferred. However, all vial samples were collected without analytically significant losses of volatiles. Tubing performance was tested at specially designed piezometers constructed so that groundwater samples could be collected from the same place through either polyethylene or Teflon tubing. It was determined that quantitatively similar samples can be collected through both types of tubing. A comparative study between peristaltic and positive displacement pumping methods was undertaken. The Teflon bladder pump (no air contact) was judged superior overall. Peristaltic suction did not appear to bias samples substantially, however, the condition of the piezometer did have a significant effect on sample representivity.

Sampling and Sample Preparation for Detection and Quantitation of Natural Toxicants in Food and Feed

1989 ◽  
Vol 72 (3) ◽  
pp. 399-404 ◽  
Author(s):  
Douglas L Park ◽  
Albert E Pohland
Keyword(s):  
Sample Preparation ◽  
Test Sample ◽  
Sampling Procedure ◽  
Sampling Plan ◽  
Representative Sampling ◽  
Factors Affecting ◽  
Natural Toxins ◽  
Continuous Stream ◽  
Food And Feed ◽  
Representative Samples

Abstract The primary goal of a sampling plan for natural toxins, i.e., mycotoxins and seafood toxins, is to obtain a sample that accurately represents the concentrations of individual components of a given lot. Factors affecting the ability of the sampling plan to accomplish this goal include: (1) nature of the analyte of interest; (2) distribution of the analyte throughout the lot, (3) physical characteristics of the product, (4) accessibility of the product to random representative sampling, (5) sampling procedure, and (6) size of sample. Sampling plans are composed of 3 distinct components: (a) sampling, (b) sample preparation, and (c) analysis. Normally, sampling contributes the largest relative error while analysis comprises the least. Automatic, continuous stream samplers provide the most representative samples for commodities such as nuts, cottonseed, and cereal grains. Good sample preparation equipment is currently available for these commodities; the use of this equipment to obtain a representative test sample is discussed.

scholarly journals Samplinghelper a web-based tool to assess the reliability of sampling strategies in sewers and receiving waters

2011 ◽  
Vol 63 (12) ◽  
pp. 2975-2982 ◽  
Author(s):  
L. Rossi ◽  
L. Rumley ◽  
C. Ort ◽  
P. Minkkinen ◽  
D. A. Barry ◽  
...  
Keyword(s):  
Chemical Compounds ◽  
Sampling Strategies ◽  
Sampling Errors ◽  
Sampling Step ◽  
Web Based ◽  
Order Of Magnitude ◽  
Theory Of Sampling ◽  
Receiving Waters ◽  
Use Of The Internet

Sampling is a key step in the analysis of chemical compounds. It is particularly important in the environmental field, for example for wastewater effluents, wet-weather discharges or streams in which the flows and concentrations vary greatly over time. In contrast to the improvements that have occurred in analytical measurement, developments in the field of sampling are less active. However, sampling errors may exceed by an order of magnitude those related to analytical processes. We proposed an Internet-based application based on a sampling theory to identify and quantify the errors in the process of taking samples. This general theory of sampling, already applied to different areas, helps to answer questions related to the number of samples, their volume, their representativeness, etc. The use of the internet to host this application facilitates use of theoretical tools and raise awareness of the uncertainties related to sampling. An example is presented, which highlights the importance of the sampling step in the quality of analytical results.

scholarly journals Mitigating Observation Perturbation Sampling Errors in the Stochastic EnKF

2015 ◽  
Vol 143 (7) ◽  
pp. 2918-2936 ◽  
Author(s):  
I. Hoteit ◽  
D.-T. Pham ◽  
M. E. Gharamti ◽  
X. Luo
Keyword(s):  
Ensemble Kalman Filter ◽  
Forecast Error ◽  
Sampling Errors ◽  
Observational Error ◽  
Error Covariance ◽  
Atmospheric Data ◽  
Observational Errors ◽  
Analysis Error ◽  
Lorenz 96 ◽  
The Impact

Abstract The stochastic ensemble Kalman filter (EnKF) updates its ensemble members with observations perturbed with noise sampled from the distribution of the observational errors. This was shown to introduce noise into the system and may become pronounced when the ensemble size is smaller than the rank of the observational error covariance, which is often the case in real oceanic and atmospheric data assimilation applications. This work introduces an efficient serial scheme to mitigate the impact of observations’ perturbations sampling in the analysis step of the EnKF, which should provide more accurate ensemble estimates of the analysis error covariance matrices. The new scheme is simple to implement within the serial EnKF algorithm, requiring only the approximation of the EnKF sample forecast error covariance matrix by a matrix with one rank less. The new EnKF scheme is implemented and tested with the Lorenz-96 model. Results from numerical experiments are conducted to compare its performance with the EnKF and two standard deterministic EnKFs. This study shows that the new scheme enhances the behavior of the EnKF and may lead to better performance than the deterministic EnKFs even when implemented with relatively small ensembles.

Materials Properties: Heterogeneity and Appropriate Sampling Modes

2015 ◽  
Vol 98 (2) ◽  
pp. 269-274 ◽  
Author(s):  
Kim H Esbensen
Keyword(s):  
Sampling Error ◽  
Special Section ◽  
Heterogeneous Materials ◽  
Heterogeneous Material ◽  
Project Managers ◽  
Sampling Errors ◽  
Sampling Process ◽  
Food And Feed ◽  
Theory Of Sampling ◽  
Regulatory Bodies

Abstract The target audience for this Special Section comprises parties related to the food and feed sectors, e.g., field samplers, academic and industrial scientists, laboratory personnel, companies, organizations, regulatory bodies, and agencies who are responsible for sampling, as well as project leaders, project managers, quality managers, supervisors, and directors. All these entities face heterogeneous materials,and the characteristics of heterogeneous materials needs to be competently understood by all of them. Before delivering analytical results for decision-making, one form or other of primary sampling is always necessary, which must counteract the effects of the sampling target heterogeneity. Up to five types of sampling error may arise as a specific sampling process interacts with a heterogeneous material; two sampling errors arise because of the heterogeneity of the sampling target, and three additional sampling errors are produced by the sampling process itself—if not properly understood, reduced, and/or eliminated, which is the role of Theory of Sampling. Thispaper discusses the phenomenon and concepts involvedin understanding, describing, and managing the adverse effects of heterogeneity in sampling.

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