Phenol removal by enhanced electrocoagulation process with persulfate salt

Introduction. Phenol is classified as priority pollutant. Phenol and its derivatives are stable in water, environmental contamination, and health concerns that are used as raw material in many chemical industries. This study investigated the removal of phenol by the reactivity of free sulfate radicals (SO4•–), activated by electrochemically generated Fe2+/Fe3+ ions which furthermore are evaluated to destroy phenol in aqueous solution. Materials and methods. In the present experimental study, electrocoagulation reactor by iron electrodes is used in the pre­sence of persulfate ions to phenol removing from aqueous solutions. In this regard, the effect of four independent variables including pH, electric current, persulfate dosage, and initial phenol concentration were studied on phenol removal. Results. The study determined the optimum conditions for maximum phenol removal using electro-persulfate process (EPS) as pH 3, 7.4 mM persulfate dosage, 27.78 mA/cm2 current density, and 100 mg/L initial phenol concentration at 30-min reaction time. The results showed that the efficiency of phenol removal was directly related to the initial persulfate dosage. In addition, the pH values, less than the phenol pKa, has slight effect onto the phenol removal. However, it was inversely correlated with a highly alkaline pH and higher phenol concentration. Conclusions. The study concluded that electro-persulfate process is an effective and robust process that can be used for handling of phenol containing wastewater.

Evaluating & Approving CMT Test Questions

Getting an ISO/IEC 17024 testing accreditation for a Certified Metrology Technician is no trivial matter. Much like a 17025 accreditation, which we are all familiar with, 17024 has a long list of requirements and procedures in place to get accredited. Not only do you need to create testing criteria, but the results also have to be statistically evaluated for reliability and validity. Creating a test that is both valid and reliable is an extensive and robust process. A valid and reliable test will certify that the education and training have properly prepared the technician to take the test and the test accurately measures the competencies and standards set forth by the accreditation body. More importantly passing the test will show that a certified technician has the required knowledge and capacity to enter the metrology field. Ensuring the process is robust has several significant components and procedures that must be followed. Psychometricians are trained professionals that ensure the efficacy and integrity of certified tests are met and maintained. Psychometricians use quantitative data and analysis procedures to determine the reliability, validity, and fairness of an assessment measure. This paper will cover the 17024 requirements and how psychometricians evaluate tests for reliability and validity. Additionally, this paper will discuss the process to follow for creating test questions, assessing their quality, and developing rigorous assessment methods that align with accreditation standards and education content.

Implementing A Human Factors Approach To Rca2: Analysis Of Resultant Safety Recommendations

Root Cause Analysis and Action (RCA2) guidelines offer fundamental improvements to traditional RCA. Yet, these guidelines lack robust methods to support a human factors analysis of patient harm events and the development of systems-level interventions. We previously described how human factors tools can be integrated into RCA2 to create a robust process called HFACS-RCA2. Prior analyses of qualitative data associated with an 18-month implementation project at a large academic health center indicated that HFACS-RCA2 fosters a more comprehensive human factors analysis of serious patient harm events and the identification of broader system interventions. The present study builds on this prior research by presenting the analysis of actual recommendations extracted from RCA reports. Results corroborate qualitative stakeholder findings that HFACS-RCA2 produced recommendations that were stronger and included more substantive changes compared to former RCA methods.

The Present State of Surface Conditioning in Cutting and Grinding

All manufacturing processes have an impact on the surface layer state of a component, which in turn significantly determines the properties of parts in service. Although these effects should certainly be exploited, knowledge on the conditioning of the surfaces during the final cutting and abrasive process of metal components is still only extremely limited today. The key challenges in regard comprise the process-oriented acquisition of suitable measurement signals and their use in robust process control with regard to the surface layer conditions. By mastering these challenges, the present demands for sustainability in production on the one hand and the material requirements in terms of lightweight construction strength on the other hand can be successfully met. In this review article completely new surface conditioning approaches are presented, which originate from the Priority Program 2086 of the Deutsche Forschungsgemeinschaft (DFG).

Digital Exhaust Controller for Pressure Detection on Die Attach Oven Curing Machine

Innovation on die attach curing process on semiconductor industry play a big role to have a robust process eliminating unwanted gross unit rejection. Resolving failures and hardware breakdowns on the exhaust system of oven curing process are the focus of this paper. Discoloration and contamination due to outgas and fumes that cannot exit the oven chamber are the effects of a failed exhaust system. Addressing the said phenomenon showing simulations, trial runs will be discussed on this paper. Promoting an innovative approach that includes real time monitoring of the system performance, and detection of its failure to prevent continuous operation with failed exhaust system are performed to have an appropriate resolution.

Mixed Method Research on Football Coaches’ Competitive Behavior

ObjectiveThe purpose of this study was to present the reliability of three validated measures, namely the System of Analysis of Instruction in Competition, the Questionnaire on Coach Instructional Behavior Expectations, and the Questionnaire on Coach Instructional Behavior Perception that could be used in a mix-method approach.MethodsThree instruments underwent a robust process of construct and reliability analysis. Inter− and intra-observer reliability was tested for the observational instrument using Cohen’s k-agreement measure. Reliability values above 0.85 were considered as a good agreement between and within observers. To verify the internal consistency of the questionnaires, the correlation coefficients were considered.ResultsThe results related to intra-observer and inter-observer reliability showed that intra-observer reliability k-agreement values ranged between 0.912 and 1 for observer 1, and 0.82 and 1 for observer 2. For inter-observer reliability, k-agreement values ranged between 0.885 and 1 between observers. Thus, values for reliability are above acceptable. The correlation coefficient values recorded for the questionnaires on instruction expectations in the competitive moment were above 0.82 and significant (p < 0.05), and for the questionnaire on instruction perception in competition above 0.88 and significant (p < 0.05). The pilot study showed some divergent results across expectations, behavior during competition, and perception about the instruction behavior.ConclusionThe observational system and the expectations and perceptions questionnaires, used in a complementary way, can be considered as a mix-method approach for studies aiming to examine coaches’ competitive behavior.

Multiple performance characteristic index optimization of dimensional accuracy and geometrical shape angle in turn-mill multitasking machining

Multiple performance objectives in turn-mill multitasking machining are investigated using the Taguchi method combined with the fuzzy theory. Using these two methods, optimized processing parameters can be rapidly identified to obtain optimized dimensional accuracy and geometrical shape angle, thus reducing machining cost and time. Herein, control factors for determining the single objective optimization parameter using the Taguchi robust process L9(34) orthogonal table were spindle speed (rpm), feed (mm/min), C-axis brake pressure (kg/cm2), axial cutting depth (mm), with dimensional accuracy and geometrical shape angle as objective characteristics. Then, signal-to-noise ratios of different groups were generated by gray correlation according to the experimental sequence to obtain the gray correlation coefficient for the calculation of the multiple performance characteristic index (MPCI). The MPCI results demonstrated that optimized dimensional accuracy was 0.005 mm and optimized geometrical shape angle was 0.004°. The optimized MPCI parameters were A3 (4000 rpm), B3 (250 mm/min), C3 (30 kg/cm2), and D3 (1.5 mm). It can reduce the processing for burr elimination and tool wear reduction by MPCI optimized process parameters.