Analysis of the anticipated transient without scram (ATWS) initiated by emergency power mode through the full scope simulator

The integrity of the reactor coolant system is severely challenged as a result of an Emergency Power Mode – ATWS event. The purpose of this paper is to simulate the Anticipated Transient without Scram (ATWS) using the full scope simulator of Angra 2 Nuclear Power Plant with the Emergency Power Case as a precursor event. The results are discussed and will be used to examine the integrity of the reactor coolant system. In addition, the results were compared with the data presented in Final Safety Analysis Report (FSAR – Angra 2) in order to guarantee the validation of the methodology and from there analyze other precursor events of ATWS which presented only plausibility studies in FSAR – Angra 2. In this way, the aim is to provide and develop the knowledge and skill necessaries for control room operating personnel to ensure safe and reliable plant operation and stimulate information in the nuclear area through the academic training of new engineers. In the presented paper the most severe scenario is analyzed in which the Reactor Coolant System reaches its highest level of coolant pressure. This scenario is initiated by the turbine trip jointly with the loss of electric power systems (Emergency Power Mode). In addition, the failure of the reactor shutdown system occurs, i.e., control rods fail to drop into the reactor core. The reactor power is safely reduced through the inherent reactivity feedback of the moderator and fuel, together with an automatic boron injection. Several operational variables were analyzed and their profiles over time are shown in order to provide data and benchmarking references. At the end of the event, it was noted that Reactor shutdown is assured, as is the maintenance of subcriticality. Residual heat removal is ensured.

Analisis Anggaran Biaya Operasional Dan Anggaran Pendapatan Terhadap Kinerja Keuangan Berdasarkan Return On Asset (ROA) Pada Counter Crocs TM Di Kota Malang

The purpose of this research is to find out the operational budget and revenue budget affect the level of financial performance at the crocs tm counter in Malang City. The design of this research is to use a quantitative descriptive method, in this research the data sources used are secondary data and primary data. The data collection techniques used in this research are interviews and observation. The data analysis technique used is quantitative descriptive analysis. It was found in the results of this research that operational variables can have a significant effect on the change ratio, while the revenue budget has no significant effect on the change ratio in Counter Crocs TM in Malang City, Malang City

Backpressure Minimization as Objective Function for Production Optimization in Absence of Wells Performance.

In the Oil & Gas sector, the production optimization is one of the most challenging problem, since it involves many operational variables linked by complex relationships. Moreover, during the asset life cycle those parameters could change. Conflicts and interactions between variables, constraints, and operational limitations could be solved holistically by an optimization tool based on an Evolutionary Algorithm. The algorithm searches for the optimum field configuration from the operational point of view, leading to the production maximization. Eni Production Department developed a tool based on this algorithm for management and optimization of surface asset hardly focused on field viewpoint. e-Rabbit (Risked Algorithm for Biogenetical Balance Integration Tool) provides integration for reservoir, well, network and process models. The present work has been developed to overcome a recurrent problem in the Oil & Gas business: the lack of data. There are many cases in which this situation occurs, for example in old fields where measurement tools and digitalization are not so widespread or in assets characterized by many wells and complex gathering systems, in which the detail on well performances could not be available. e-Rabbit, to perform its optimization, requires that information so, under those conditions, somehow, it is necessary to find another way to be able to optimize and manage the surface asset. A novel technique to optimize the whole production system has been introduced, whose objective function rely on backpressure minimization. To verify its effectiveness two case studies have been analyzed comparing the proposed optimal configuration with the output of the classical e-Rabbit - optimization.

Computer-Assisted in Coiled Tubing Perforation Limitations: A Case Study from MA-X Gas Well

This paper seeks to determine the optimum operating conditions for deploying casing perforation guns based on CT to target depths in gas well MA-X by utilising Orpheus Model in CERBERUS. Orpheus assisted to solve the complicated scenarios and complex analysis involves mathematical modelling which is necessitates for computer processing powers. This study investigated four different Coiled Tubing (CT) intervention operational variables namely borehole assembly, CT grade outer diameter (OD), well fluid type and fractional reducer application included examined two scenarios which are running tools in (RIH) and pulling out from borehole (POOH). Only CT workstring with outer diameter between 1-1/4 inch and 2-7/8 inch is considered due to the wellbore completion minimum restriction. Constrained by economic and logistical reasons, only fresh water, 2% KCl, 15% HCl, sea water and diesel will be considered for the well bore fluid. Fractional reducer effects was simulated and analysed. Based on simulation results, the CT outer diameter 1-3/4 inch workstring optimized operation, the CT grade is QT1000 increased mechanical properties. A suitable well fluid is sea water with application of friction reducer improve CT perforation performances to achieve maximum target depth.

Exploiting the Potential of Supported Magnetic Nanomaterials as Fenton-like Catalysts for Environmental Applications

In recent years, the application of magnetic nanoparticles as alternative catalysts to conventional Fenton processes has been investigated for the removal of emerging pollutants in wastewater. While this type of catalyst reduces the release of iron hydroxides with the treated effluent, it also presents certain disadvantages, such as slower reaction kinetics associated with the availability of iron and mass transfer limitations. To overcome these drawbacks, the functionalization of the nanocatalyst surface through the addition of coatings such as polyacrylic acid (PAA) and their immobilization on a mesoporous silica matrix (SBA15) can be factors that improve the dispersion and stability of the nanoparticles. Under these premises, the performance of the nanoparticle coating and nanoparticle-mesoporous matrix binomials in the degradation of dyes as examples of recalcitrant compounds were evaluated. Based on the outcomes of dye degradation by the different functionalized nanocatalysts and nanocomposites, the nanoparticles embedded in a mesoporous matrix were applied for the removal of estrogens (E1, E2, EE2), accomplishing high removal percentages (above 90%) after the optimization of the operational variables. With the feasibility of their recovery in mind, the nanostructured materials represented a significant advantage as their magnetic character allows their separation for reuse in different successive sequential batch cycles.

Response surface optimization and modeling of caffeine photocatalytic degradation using visible light responsive perovskite structured LaMnO3

Caffeine is a refractory pollutant of emerging concern that evades conventional waste-water treatment techniques. Here, we report the synthesis of visible light responsive perovskite structured LaMnO­3 photocatalyst using modified Pechini method and utilized it as an efficient photocatalyst for caffeine degradation. XRD, BET, UV-Vis, NH3-TPD, and SEM were used to characterize the photocatalyst. Response surface methodology using Central composite design was used to investigate the effect of three operational variables; catalyst dosage, initial caffeine concentration and pH on the caffeine photocatalytic degradation efficiency. The functional relationship between these operational variables and caffeine photocatalytic degradation efficiency was established be a second order polynomial model. The results of the response surface analysis indicate caffeine degradation efficiency is most significantly affected by catalyst dosage and pH. The optimal values of operational obtained by response surface optimization were found be 3.5 g/L for catalyst dosage, 7.9 and 44.6 mg/L for pH and initial caffeine concentration respectively given the caffeine degradation efficiency of 93.9%.

Application of a Combined Adsorption–Ozonation Process for Phenolic Wastewater Treatment in a Continuous Fixed-Bed Reactor

This work studied the removal of phenol from industrial effluents through catalytic ozonation in the presence of granular activated carbon in a continuous fixed-bed reactor. Phenol was chosen as model pollutant because of its environmental impact and high toxicity. Based on the evolution of total organic carbon (TOC) and phenol concentration, a kinetic model was proposed to study the effect of the operational variables on the combined adsorption–oxidation (Ad/Ox) process. The proposed three-phase model expressed the oxidation phenomena in the liquid and the adsorption and oxidation on the surface of the granular activated carbon in the form of two kinetic constants, k1 and k2 respectively. The interpretation of the constants allow to study the benefits and behaviour of the use of activated carbon during the ozonisation process under different conditions affecting adsorption, oxidation, and mass transfer. Additionally, the calculated kinetic parameters helped to explain the observed changes in treatment efficiency. The results showed that phenol would be completely removed at an effective contact time of 3.71 min, operating at an alkaline pH of 11.0 and an ozone gas concentration of 19.0 mg L−1. Under these conditions, a 97.0% decrease in the initial total organic carbon was observed.

Operational Variables on the Processing of Porous Titanium Bodies by Gelation of Slurries with an Expansive Porogen

Colloidal processing techniques, based on the suspension of powders in a liquid, are very versatile techniques to fabricate porous structures. They can provide customized pores, shapes and surfaces through the control of operational parameters, being the base of the alternative additive manufacture processes. In this work disperse and stable titanium aqueous slurries has been formulated in order to process porous materials by the incorporation of methylcellulose (MC) as a gelation agent and ammonium bicarbonate as an expansive porogen. After casting the slurries and heating at mild temperatures (60–80 °C) the methylcellulose gels and traps the gas bubbles generated by the ammonium bicarbonate decomposition to finally obtain stiff porous green structures. Using an experimental design method, the influence of the temperature as well as the concentration of gelation agent and porogen on the viscosity, apparent density and pore size distribution is analyzed by a second-order polynomial function in order to identifying the influence of the operating variables in the green titanium porous compact. After sintering at 1100 °C under high vacuum, titanium sponges with 39% of open porosity and almost no close porosity were obtained.

Aerial Robotic Systems Drones for Contact-Based Ultrasonic Wall Thickness UT Measurements at Height

The use of aerial robotic systems that physically contact oil and gas structural assets to obtain measurement data in offshore and marine environments carries unique challenges and operational variables. The objectives of this paper are to demonstrate, with examples, how these aerial robotic systems afford safer, cheaper, and better nondestructive testing (NDT) measurement collection methodology and allow more robust insight into assets conditions than the slower, less safe, and more expensive manual method. To take NDT measurements such as Ultrasonic Wall Thickness (UT) Measurements at height, currently one needs to utilize a lift, ladders or other solutions to reach areas on certain assets. This can be both dangerous, due to the possibility of falls, and time consuming. Utilizing an aerial robotics platform for contact based (not visual) NDT measurements such as Ultrasonic Thickness (UT) allows workers to remain safely on the ground. Drones, with robotic arms, have the potential to improve inspection, testing and data collection. This paper explores an aerial robotic system that flies up to a structure with a metal sub-straight, then under full autonomous software control, touches a UT measurement probe to the target and records the measurement data compliant with American Petrolium Institute (API) and other standards. The use of aerial robotics systems for NDT is still a new and novel application utilizing existing technologies such as electronic measurement readers, drones, etc. with a system of complex integrations that allows for a better application of science. Aerial Robotic NDT systems have the potential to improve the inspection, testing and data collection aspects of coated and uncoated assets, in part, by making the NDT measurement process easier and safer thus allowing for more frequent measurements and/or a larger quantity of measurement samples. When possible, working at heights should be eliminated as part the hierarchy of fall protection stipulated by both OSHA and ANSI. For this reason alone, the use of aerial robotic systems is important now and in the immediate future Oil & Gas infrastructure, including Offshore. This paper intends to provide readers an awareness of this new technology as well as provide information about its efficacy, limitations and operational requirements.

The Deteriorating Role of Active Transactional Leadership on Employees Perceived Uncertainty and Emotional Exhaustion: Evidence from Educational Sector of Thailand

Given the seriousness of the COVID-19 crisis that impacted organizations all over the world, study on the operational variables impacting the psychological well-being of the workers of an organization affected by the crisis has been insufficient. Therefore, the present study aimed to highlight the role of active transactional leadership of employees’ emotional exhaustion through their perceived uncertainties. For this purpose, a cross-sectional study has been carried out among 309 employees working in Thai educational sector and the data was collected through self-administered questionnaires. The collected data was then analyzed by adopting PLS-SEM approach using SmartPLS 3.0 software. The findings of the study confirmed the direct relationships of active transactional leadership with perceived uncertainties. Also, the study established the direct association of perceived uncertainties with employee emotional exhaustion. The findings further confirmed the mediation of perceived uncertainties between the relationship of active transactional leadership and employee emotional exhaustion.