Use Of Process Control Research Articles

Laboratory Performance Evaluation of Asphalt-Treated Cold Recycled Mixtures Using Existing Practical Tests

Agencies currently utilize several proxy tests, related to level of compaction (density) and moisture content, to assess the quality of a recycled pavement during construction. These proxy tests are not completely able to indicate sufficient quality or stability of recycled pavements under trafficking or surfacing, especially at early ages. The lack of sound and rapid tests for use in process control and acceptance during construction limits the use of the recycling techniques by agencies, therefore they do not fully benefit from the advantages that pavement recycling offers. This study evaluates the viability of currently available simple and practical stiffness tests (i.e., soil stiffness gauge and light weight deflectometer tests), deformation resistance tests (i.e., Marshall hammer test), and penetration resistance tests (i.e., dynamic cone penetration test) to characterize the properties of asphalt-treated cold recycled mixtures. The scope of the work included laboratory testing of 18 different cold recycled mixtures, prepared through different processes combining different binding agents and filler types, at different curing times via the selected tests. The collected data were analyzed to evaluate these tests in relation to their repeatability characteristics and versatility to capture the performance of recycled materials with respect to changes in curing time, type of stabilizing/recycling agent, and presence of active filler. The data obtained showed the ability of these tests to capture the effect of curing. Moreover, these tests were found to be sensitive to changes in the recycling agent type, recycling agent content, and presence of active filler.

Setup for electrical resistance measurement for laser material deposition with coaxial wire feed and use for process control

Within laser additive manufacturing (directed energy deposition with laser beam), processes are further distinguished by the form of the filler material. In terms of availability, storage, safety, and cost, wire is commonly the preferred filler material in comparison to powder. Despite these advantages, due to the different material transfer modes, a greater process control is required. Within this work, an experimental setup for electrical-resistance-measurement within the laser material deposition process with a coaxial wire feed and its possible use for an automated process control is investigated. The measurement is performed between a wire, a substrate, and over the melt pool. One main influencing factor on process stability is derived from the timing of the trigger sequence of the laser power, process feed, and wire feed at the start and end points of every track. Consequently, inaccurate settings of the trigger sequence can, e.g., lead to deviations in track length and part geometry. Additionally, a smooth transfer of the wire into the melt pool is imperative during part build-up to ensure a stable deposition process. Variation in laser power, wire feed, process feed, or wire transfer mode can lead to process instabilities. This can result in imperfections, bonding defects, or pores in the tracks and layers that will add up in built components and must be avoided for defectfree three-dimensional geometries. Within the experiments, it is investigated whether the resistance-measurement provides consistent results under varying conditions and potentially can be utilized to automate the trigger sequence of deposition. Furthermore, it is investigated whether different wire transfer modes can be linked to the measured resistance values during welding of single tracks.

The Hitchhiker's Guide to Hydrogen Peroxide Fumigation, Part 2: Verifying and Validating Hydrogen Peroxide Fumigation Cycles.

Introduction: Part 1 of this two-part series describes the use of hydrogen peroxide as a fumigant and compares it with other fumigants on the market. Technical requirements are outlined while considering physical and biological limitations of the system. This second part focuses primarily on the use of process controls to verify and validate hydrogen peroxide fumigations. Finally, a model encompassing the entire fumigation process is presented. Methods: Part 2 of the series focuses on the authors' long-time personal experiences in room and filter fumigation using various fumigation systems and is supplemented with relevant literature searches. Results: The reader is introduced to the planning and implementation of fumigation process validations. Biological indicators help users develop safe and efficient processes. Chemical indicators can be used as process controls, while measuring physical parameters will help avoid condensation of hydrogen peroxide. How many biological and chemical indicators and what type should be applied for cycle development are additionally explained. Discussion: It is important to consider numerous technical requirements when planning to implement hydrogen peroxide fumigation at an institution. Also, considerable thought needs to go into the verification and validation of the fumigation process. Conclusions: Part 1 of this series presents an overview of different fumigation systems based on hydrogen peroxide on the market and their technical requirements. Part 2 focuses on validation and verification of hydrogen peroxide fumigation while considering the entire fumigation process. The two parts together will serve users as a guide to establishing hydrogen peroxide fumigations at their facilities.

Experimental and Mathematical Tools to Predict Droplet Size and Velocity Distribution for a Two-Fluid Nozzle

Despite progress in laser-based and computational tools, an accessible model that relies on fundamentals and offers a reasonably accurate estimation of droplet size and velocity is lacking, primarily due to entangled complex breakup mechanisms. Therefore, this study aims at using the integral form of the conservation equations to create a system of equations by solving which, the far-field secondary atomization can be analyzed through predicting droplet size and velocity distributions of the involved phases. To validate the model predictions, experiments are conducted at ambient conditions using water, methanol, and acetone as model fluids with varying formulation properties, such as density, viscosity, and surface tension. Droplet size distribution and velocity are measured with laser diffraction and a high-speed camera, respectively. Finally, an attempt is made to utilize non-scaled parameters to characterize the atomization process, useful for extrapolating the sensitivity analysis to other scales. The merit of this model lies in its simplicity for use in process control and optimization.

The Hitchhiker’s Guide to Hydrogen Peroxide Fumigation, Part 2: Verifying and Validating Hydrogen Peroxide Fumigation Cycles

Introduction: Part 1 of this two-part series describes the use of hydrogen peroxide as a fumigant and compares it with other fumigants on the market. Technical requirements are outlined while considering physical and biological limitations of the system. This second part focuses primarily on the use of process controls to verify and validate hydrogen peroxide fumigations. Finally, a model encompassing the entire fumigation process is presented. Methods: Part 2 of the series focuses on the authors’ long-time personal experiences in room and filter fumigation using various fumigation systems and is supplemented with relevant literature searches. Results: The reader is introduced to the planning and implementation of fumigation process validations. Biological indicators help users develop safe and efficient processes. Chemical indicators can be used as process controls, while measuring physical parameters will help avoid condensation of hydrogen peroxide. How many biological and chemical indicators and what type should be applied for cycle development are additionally explained. Discussion: It is important to consider numerous technical requirements when planning to implement hydrogen peroxide fumigation at an institution. Also, considerable thought needs to go into the verification and validation of the fumigation process. Conclusions: Part 1 of this series presents an overview of different fumigation systems based on hydrogen peroxide on the market and their technical requirements. Part 2 focuses on validation and verification of hydrogen peroxide fumigation while considering the entire fumigation process. The two parts together will serve users as a guide to establishing hydrogen peroxide fumigations at their facilities.

Potential of using statistical quality control in agriculture 4.0

Agriculture 4.0 involves the incorporation of information and communication technologies into machines, equipment, and sensors for use in agricultural production systems. It aims to ease decision-making in agricultural processes. Statistical Quality Control (SQC) is a statistical method with several techniques and tools used to analyze the variability. These tools can be used to provide important information for decision making, including for mechanized agricultural operations. This paper aimed to characterize the worldwide scientific literature on Statistical Process Control use in mechanized agricultural processes, demonstrating its potential to be incorporated into Agriculture 4.0. Our research involved a bibliometric survey on Scopus and Academic Google databases. The analyzed studies allowed us to infer that SQC tools may improve understanding of mechanized operations and be used in Agriculture 4.0. Such features can also streamline and enhance decision making, converting big data into useful information.

1232. Potential Health and Cost Outcomes of Optimized Statistical Process Control Use for Surgical Site Infection Surveillance

BackgroundSurgical site infections (SSIs) are common (160,000–300,000 per year in the United States) and costly ($6,000–$25,500 per event) healthcare-associated infections with potentially lethal outcomes (2.1%–6.7% mortality rate). A prior analysis by our group suggested that statistical process control (SPC) can detect SSI outbreaks earlier than traditional epidemiological surveillance methods. This study aimed to quantify the potential impact of SPC surveillance on patient outcomes (prevented SSIs and deaths) and healthcare costs.MethodsWe retrospectively analyzed 30 SSI outbreaks occurring over a period of 8 years in a network of 50 community hospitals from the Southeastern United States. We applied 24 control chart variations, including 2 optimized for SSI surveillance, 6 with expert-defined pre-outbreak baselines (used in our pilot study), 4 with lagged rolling baselines (idem), and 12 common practice ones (using rolling baselines with no lag or fixed baselines). The charts used procedure-specific data from either the outbreak hospital or the entire network to compute baseline SSI rates. We calculated the average SSI rates during, before and after the outbreaks, and the months elapsed between SPC and traditional detection. We then used these values to estimate the number of SSIs that could have been prevented by SPC, and corresponding deaths avoided and cost savings (Figure 1).ResultsOptimized charts detected 96% of the outbreaks earlier than traditional surveillance, while pilot study and common practice charts did so only 65% (58%) of the time (Figure 2). Optimized charts could potentially prevent 15.2 SSIs, 0.64 deaths, and save $226,000 in excess care costs per outbreak. Overall, charts using network baselines performed better than those relying on local hospital data. Commonly used variations were the least effective, but were still able to improve on traditional surveillance (Figure 3).ConclusionSPC methods provide a great opportunity to prevent infections and deaths and generate cost savings, ultimately improving patient safety and care quality. While common practice SPC charts can also speed up outbreak detection, optimized SPC methods have a significantly higher potential to prevent SSIs and reduce healthcare costs. Disclosures All authors: No reported disclosures.

Beware of r2 even for test datasets: Using the latest measured y‐values (r2LM) in time series data analysis

AbstractThe determination coefficient of a test dataset, r2, is calculated and used to compare the performance of adaptive soft sensors and discuss the possibility of their practical use. However, soft sensors that give very high r2 values do not always have sufficient predictive accuracy for use in process control. Therefore, a new measure for soft sensors based on the latest measured y‐values (r2LM) is proposed. This metric can be used in time series data analysis to determine whether the variations in y‐values estimated by soft sensors come from variations in the input variables or those of the latest measured y‐values. Through case studies using real and simulated datasets, it is confirmed that low r2LM values correspond to meaningless soft sensors, even when their r2 value is high, and that high r2LM values imply that the estimation results are useful for process control with soft sensors. Python and MATLAB codes for computing r2LM can be downloaded from GitHub: https://github.com/hkaneko1985/r2lm.

Development of online soft sensors and dynamic fundamental model-based process monitoring for complex sulfide ore flotation

Complex sulfide ores are difficult to process and often require multi-stage sequential flotation. Process outputs such as grade and recovery in each stage are affected by various sub-processes in the system, and it is crucial to monitor the performance in order to maximize the production. In this work, we have proposed and implemented a dynamic monitoring scheme using fundamental modeling and an online soft sensor network for real-time measurements of grade and recovery. Dynamic fundamental models for lead and zinc recovery were developed to represent the multi-stage rougher flotation for lead-zinc sulfide ores. A soft sensor network was built to measure the grade and recovery in real-time using support vector machine classification and regression on multivariate image data. A factorial design with feed particle size, collector dosage in the lead rougher flotation stage, and collector dosage in the zinc rougher flotation stage as the design variables was used to obtain diverse process conditions for validation. Successful validation at the entire range of process conditions demonstrates the potential of the technique for use in process control and monitoring applications. Changes in the collector dosage were monitored in the lead and zinc rougher flotation stages using state and parameter estimates of the fundamental model structure. The process monitoring framework can be extended to monitor other key variables in the process.

Radial-mode abrasive waterjet turning of short carbon–fiber-reinforced plastics

ABSTRACTAn experimental study is carried out for single-pass radial-mode abrasive waterjet (AWJ) turning of a short carbon–fiber-reinforced polyetheretherketone (PEEK) specimen to understand the machining process and the effects of major process variables (feed speed, water pressure, abrasive mass flow rate, nozzle tilt angle, and rotational surface speed) on the major machining performance measures, that is, the depth of cut, material removal rate (MRR) and surface roughness. It is found that high water pressure, normal nozzle impact angle and high rotational speed with suitably selected feed speed and abrasive flow rate may be selected to achieve a high MRR without significantly compromising the surface roughness. Mathematical models for the three cutting performance measures are then developed for use in process control.

Reduction of Pathogens, Indicator Bacteria, and Alternative Indicators by Wastewater Treatment and Reclamation Processes

In wastewater reclamation systems, microbiological monitoring is conducted to ensure that the users of reclaimed water are exposed to minimal risks from exposure to pathogens. Typically, utilities rely on the use of process controls to remove or inactivate pathogens. Routine monitoring of indicator organisms is conducted to evaluate overall process performance and for regulatory compliance. However, the effectiveness of individual treatment processes for removal of pathogens is dependent on process variables. This project was conducted to compare the effectiveness of biological treatment, filtration, and disinfection for removal of bacterial and viral indicators, enteric viruses, and protozoan pathogens. Six full-scale treatment facilities were each sampled a minimum of four times over a one year period. The relative impacts of loading conditions, process design, and operating parameters on the removal/inactivation of a suite of nine microbial species (bacteria, coliphages, enteric viruses, and protozoan pathogens) was evaluated. Bacterial removal was consistent for all types of biological systems, however, increased virus removal was associated with biological nutrient removal and nitrification processes. Parasite removal was highly variable. The effectiveness of filtration was impacted most by the use of upstream chemicals (either chlorine or coagulant chemicals). Chlorine disinfection was more effective in cases where ammonia levels were low (biological nutrient removal or nitrification facilities). Infectivity assays for protozoan pathogens suggest that the proportion of infective cysts or oocysts increases with increasing level of treatment. This title belongs to WERF Research Report Series ISBN: 9781843397304 (Print) ISBN: 9781780404370 (eBook)

Managerial Control Policies in NPD Projects and the Moderating Role of Team Knowledge Tacitness

An increasingly important issue facing new product development (NPD) project managers is to ensure that their teams develop high quality products in a timely manner and within budget. Managers try to achieve this by exercising managerial control over their project teams in a way that stimulates this adherence to organizational goals without hampering the problem solving and creativity that is required within these projects. The operations management literature is inconclusive, however, on what such managerial control should look like. This study investigates the effectiveness of outcome, process controls, and clan controls and how their effects are influenced by the extent to which project team knowledge is tacit. Results of a study of 227 NPD projects show that the use of outcome controls and clan controls are generally positively associated with project execution success, while the use of process controls is largely unrelated to project execution success. Outcome controls, however, appear to be unrelated to project success when team knowledge is tacit and clan controls are similarly ineffective when team knowledge is explicit. As such, our study suggests that these managerial control policies act as supplements and managers should emphasize either of them depending on the level of team knowledge tacitness.

Optimization of an Adsorption-Elution Method with a Negatively Charged Membrane to Recover Norovirus from Lettuce.

Viral pathogens, such as norovirus (NoV), are frequently associated with foodborne gastroenteritis worldwide, and the detection of NoV in food requires appropriate methods and the use of process controls. In this study, an adsorption-elution concentration method using negatively charged membranes was optimized to recover NoV from lettuce, using murine norovirus 1 (MNV-1) as a human NoV (HuNoV) surrogate. Initially, three elution buffers were evaluated by direct elution using a Stomacher® apparatus with a filter bag and different concentrations of MNV-1 genomic copies. The eluates were filtered in a Stericup® and concentrated by a Centriprep Concentrator®, and the viral RNA was quantified by real-time PCR that was preceded by reverse transcription. The MNV-1 recovery efficiency varied based on the buffers used, ranging from 5.2 to 9.8% for PBS pH 7.2, 0.2-18% for glycine NaCl pH 9.5 and 10.8-33.3% for glycine Tris-HCl pH 9.5. Further analysis of the glycine Tris-HCl pH 9.5 buffer revealed that gentle-shaking, direct elution could replace the use of a Stomacher®, with recovery rates reaching 66 and 32% for MNV-1 and HuNoV, respectively, all of which suggested that this procedure is a quick and efficient method for recovering NoV from lettuce.

Similar concentration and extraction recoveries allow for use of turnip crinkle virus as a process control for enteroviruses in water

Enteric viruses are etiological agents of waterborne disease that may be detected using molecular techniques such as PCR. However, processing water samples in preparation for PCR typically involves concentration of samples and extraction of nucleic acids, steps that have low and variable recovery efficiencies. This study evaluated a plant virus, turnip crinkle virus (TCV), for its ability to serve as a process control for human enteroviruses during concentration and extraction procedures. Enteroviruses and TCV have similar sizes and morphologies, and both contain single stranded, positive-sense RNA genomes. Results from the study demonstrate that the tested viruses experience similar losses during sample processing. Virus recoveries averaged 0.03% for EV and 0.02% for TCV from DI water, and 0.004% for EV and 0.009% for TCV from a creek sample. Surface water and wastewater samples from around the U.S. were evaluated for the presence of TCV to ensure the virus is not present in environmental samples. All were negative. With similar recovery efficiencies to EV, TCV may be a suitable process control for enteroviruses in environmental water samples in the U.S. Use of process controls as proposed in this study would allow better detection and quantitation methods to be employed in water quality monitoring.

Sequential Partial Ozonation for the Treatment of Wastewater Concentrate: Practical Implications From a Conventional and (Eco) Toxicological Perspective

This article compares multi-stage ozonation-biological treatment processes [O3 - Biodegradation - O3 - Biodegradation] and conventional partial ozonation processes [O3 - Biodegradation] for the removal of SCOD and toxicity from a recalcitrant and toxic wastewater concentrate. Both direct (pH 7.5) and advanced (pH 11.5) ozonation are evaluated. Short-term estimation methods for biodegradability (respirometry) and toxicity (30 min Vibrio fisheri luminescence inhibition) are evaluated for their use in process control.

Explaining Temporal Change in Artifacts by the use of Process Controls

Process controls are guidelines employed during performance of a manufacturing task that reduce variation in the final product. The manufacture of stone tools, one of many endeavors that has depended on process controls to yield consistent results, can be examined to understand how the concepts of controls may be integrated with theories of stylistic variation. Not only do process controls explain why styles are recognizable, they help to explain why one style differs from another. Selected examples reveal how pervasive process controls are in an archaeological context and explain how their effects may be recognized. Suggestions are then offered as to how the effects produced by process controls may be quantified.

Development and Implementation of a Zinc Electrowinning Process Simulation

A process simulation of industrial zinc electrowinning was developed for potential use in process control and optimization. The simulation improved on the abilities of a conventional mass and energy balance by including predictions of voltage, current efficiency and reaction kinetics. The simulation is based on previous models developed in the literature. These models were modified and are now presented in C++ within a process simulation program making the simulation dynamic and time dependent. Relations for solution conductivity, density and bubble effects have been incorporated as well as estimates of dissolved ion activities using Pitzer parameters,. New kinetic parameters for zinc deposition and hydrogen evolution have been incorporated. The new simulation was validated against data presented in the literature for past models. An industrial cell house was simulated and good agreement was found between industrial and simulated data.

Extraction of food-borne viruses from food samples: A review

Detection of food-borne viruses such as noroviruses, rotaviruses and hepatitis A virus in food products differs from detection of most food-borne bacteria, as most of these viruses cannot be cultivated in cell culture to date. Therefore, detection of food-borne viruses in food products requires multiple steps: first, virus extraction; second, purification of the viral genomic material (RNA for the majority of food-borne viruses); and last, molecular detection. This review is focused on the first step, the virus extraction. All of the numerous published protocols for virus extraction from food samples are based on 3 main approaches: 1) (acid adsorption-) elution-concentration; 2) direct RNA extraction; and 3) proteinase K treatment. This review summarizes these virus extraction approaches and the results obtained from published protocols. The use of process controls is also briefly described.

Indicator organisms in meat and poultry slaughter operations: their potential use in process control and the role of emerging technologies.

Measuring commonly occurring, nonpathogenic organisms on poultry products may be used for designing statistical process control systems that could result in reductions of pathogen levels. The extent of pathogen level reduction that could be obtained from actions resulting from monitoring these measurements over time depends upon the degree of understanding cause-effect relationships between processing variables, selected output variables, and pathogens. For such measurements to be effective for controlling or improving processing to some capability level within the statistical process control context, sufficiently frequent measurements would be needed to help identify processing deficiencies. Ultimately the correct balance of sampling and resources is determined by those characteristics of deficient processing that are important to identify. We recommend strategies that emphasize flexibility, depending upon sampling objectives. Coupling the measurement of levels of indicator organisms with practical emerging technologies and suitable on-site platforms that decrease the time between sample collections and interpreting results would enhance monitoring process control.

Current Methods for Extraction and Concentration of Enteric Viruses from Fresh Fruit and Vegetables: Towards International Standards

Virus-contaminated soft fruits or vegetables are increasingly identified as causes of foodborne viral illness. Noroviruses and hepatitis A virus are the most common pathogens in viral infections transmitted by these kinds of foods. To improve microbiological detection and monitoring and to increase insights into the contribution of fruits and vegetables to foodborne viral transmission, sensitive, reliable, and standardized methods are needed. More studies on virus detection methods for foods are being published, but validated consensus protocols are not yet available. In this paper, different methodologies are reviewed critically. The use of process controls and internal amplification controls is discussed.