Reactive tracers reveal hydraulic and control instabilities in full-scale activated sludge plant

2008 ◽  
Vol 57 (7) ◽  
pp. 1001-1007 ◽  
Author(s):  
D. Braun ◽  
W. Gujer
Keyword(s):  
Large Scale ◽  
Oxygen Sensor ◽  
Electrochemical Sensors ◽  
Aeration Tank ◽  
Control Loop ◽  
Reactive Tracers ◽  
And Control ◽  
Present Case Study ◽  
Aeration Control

The hydraulic characteristics of aeration tanks in WWTPs have a major impact on the degradation of pollutants, as well as on the control of the aeration. In particular in long reactors, which are not separated by baffles, hydraulic shortcuts or large scale recirculation can lead to a loss of performance. This work demonstrates that reactive tracers such as ammonium and oxygen can be used to investigate the hydraulics of aeration tanks in detail. With the use of electrochemical sensors it is possible to investigate effects in a broad range of time scales. In the present case study a slow oscillation of the aeration control loop was investigated. Large scale recirculation in the aeration tank and fast fluctuations of the ammonium concentrations close to the oxygen sensor were identified as the cause of these oscillations. Both, the recirculation as well as the fluctuation of the ammonium have a substantial influence on the performance of the aeration tank and the aeration control loop.

The Big-headed Ant Pheidole megacephala: a new threat to monsoonal northwestern Australia

1998 ◽  
Vol 4 (3) ◽  
pp. 250 ◽  
Author(s):  
Benjamin D. Hoffmann
Keyword(s):  
Agricultural Production ◽  
Large Scale ◽  
Foraging Ecology ◽  
Potential Threat ◽  
Pheidole Megacephala ◽  
Realistic Option ◽  
Northwestern Australia ◽  
Nature Park ◽  
And Control

The Big-headed Ant Pheidole megacephala is a major threat to native invertebrate assemblages and to agricultural production world-wide. This paper reviews its known biology including its foraging ecology, colony founding and dispersal behaviour. A case study is presented to illustrate its potential conservation significance for northern Australia. At Howard Springs Nature Park in the Darwin region of the Northern Territory, an infestation of P. megacephala was found to cover 25 ha and is continuing to spread, with its distribution centred on a rainforest patch. The abundance of P. megacephala within the rainforest was 37?110 times that of total native ant abundance at uninfested sites. Only two individuals of a single native ant species were found in the highest abundance of P. megacephala and abundance of other invertebrates was only 15% of natural levels. Pheidole megacephala is a serious potential threat to native biodiversity in monsoonal Australia. Successful eradication on a large scale is a realistic option and control methods are discussed, including chemicals and fire.

scholarly journals Thermofluid Modelling of Large-Scale Orchards for Optimal Design and Control of Active Frost Prevention Systems

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 378
Author(s):  
Ercan Atam ◽  
Se-Woon Hong ◽  
Alessia Arteconi
Keyword(s):  
Optimal Design ◽  
Control Systems ◽  
Large Scale ◽  
Initial Conditions ◽  
Minimum Energy ◽  
Prunus Armeniaca ◽  
Thermal Dynamics ◽  
Heating Systems ◽  
And Control

Accurate modelling and simulation of temperature dynamics in large-scale orchards is important in many aspects, including: (i) for the calculation of minimum energy required to be used in optimal design of active frost prevention energy systems (fully renewable or partially renewable) to prevent freezing of fruit flowers, buds, or leaves; (ii) for testing frost prevention control systems before real-implementation which regulate active heating systems inside orchards targeted to prevent frost. To that end, in this study, first, a novel and sophisticated parametric computational thermofluid dynamics (CTFD) model for orchard air thermal dynamics for different orchard parameters (such as fruit type, climate, number of trees, their sizes, and distance between them) and boundary/initial conditions was developed and validated with field data from the literature. Next, the use of the developed parametric CTFD model was demonstrated through a case study to calculate the minimal thermal energy required to prevent frost under different frost levels in a test Prunus armeniaca orchard located in Malatya, Turkey, which is the world capital for dry apricot production.

scholarly journals Power monitoring and control for large scale projects: SKA, a case study

2016 ◽  
Author(s):  
Domingos Barbosa ◽  
João Paulo Barraca ◽  
Dalmiro Maia ◽  
Bruno Carvalho ◽  
Jorge Vieira ◽  
...  
Keyword(s):  
Large Scale ◽  
Monitoring And Control ◽  
Power Monitoring ◽  
And Control

scholarly journals A decomposition algorithm of Petri net utilizing index function

Filomat ◽  
2020 ◽  
Vol 34 (15) ◽  
pp. 5085-5094
Author(s):  
Kai-Qing Zhou ◽  
Li-Ping Mo ◽  
Chang-Feng Chen ◽  
Wei Jiang
Keyword(s):  
Petri Net ◽  
Large Scale ◽  
Dynamic Properties ◽  
Decomposition Algorithm ◽  
State Explosion ◽  
Decomposition Approach ◽  
Index Function ◽  
Knowledge Based ◽  
And Control

Recently, it is difficult to simulate, analyze and control a real knowledge-based system using the correspondence Petri net (PN) when there exist many current states. To overcome the state explosion problem of PN, an efficient decomposition algorithm is presented to divide a large-scale PN into a series of corresponding sub-PNs by keeping the consistency of dynamic properties. In this novel decomposition approach, an index function is defined to judge the subnet needs to be decomposed or not. Furthermore, an exhaustive analysis on the consistency of related dynamic properties is also discussed between the original PN and the corresponding sub-PNs. Finally, a case study is carried out to illustrate the feasibility and validity of the proposed approach.

scholarly journals Reception of literary works in the original and translation. A case study: Students’ responses

2021 ◽  
Vol 105 ◽  
pp. 01005
Author(s):  
Alla Perminova
Keyword(s):  
Large Scale ◽  
Self Esteem ◽  
Literary Translation ◽  
Small Scale ◽  
Professional Expertise ◽  
Source Text ◽  
English Reader ◽  
Class Discussions ◽  
Present Case Study

The present case study applies the Reception Model of Literary Translation that places a high value on multiplicity and subjectivity of a target readership’s response to a source text. The article highlights a three-stage experiment that analyzes Literary Translation majors’ responses to Yuriy Vynnychuk’s novel Tango of Death in the original and in Michael M. Naydan and Olha Tytarenko’s translation. The data on the students’ response was collected by means of brainstorming sessions, in-class discussions, written reports, essays, and questionnaires. The informants agreed that on a large scale the translators succeeded in recreating the fusion of tragedy and humor of Vynnychuk’s writing. However, on a small scale, certain translation decisions initiated polemics. Thus, some students criticized the recurrent translators’ decision to alter the author’s syntax, which is one of Vynnychuk’s stylistic idiosyncrasies. Whereas others would fully approve of this technique, stating that otherwise the text would be incomprehensible for an English reader. Another stumbling block was associated with culturally biased units. Some students criticized the literality of conveying a number of Ukrainian set expressions, others saw in it a manifestation of a foreignization strategy. The students’ feedback prompted a conclusion about the experiment helping to build up the learners’ confidence in their professional expertise, boost their self-esteem and empathy, as well as to prepare them for actual translating projects of their own.

scholarly journals Into the thirteenth Month: A Case Study on the Outbreak Analytics and Modeling the spread of SARS-CoV-2 Infection in Pune City, India

2021 ◽  
Author(s):  
Joy Monteiro ◽  
Bhalchandra Pujari ◽  
Sarika Maitra Bhattacharrya ◽  
Anu Raghunathan ◽  
Ashwini Keskar ◽  
...  
Keyword(s):  
Real Time ◽  
Large Scale ◽  
Information Dissemination ◽  
Public Access ◽  
Accurate Information ◽  
Time Data ◽  
Outbreak Response ◽  
First Case ◽  
And Control

With more than 140 million people infected globally and 3 million deaths, the COVID 19 pandemic has left a lasting impact. A modern response to a pandemic of such proportions needs to focus on exploiting all available data to inform the response in real-time and allow evidence-based decision-making. The intermittent lockdowns in the last 13 months have created economic adversity to prevent anticipated large-scale mortality and relax the lockdowns have been an attempt at recovering and balancing economic needs and public health realities. This article is a comprehensive case study of the outbreak in the city limits of Pune, Maharashtra, India, to understand the evolution of the disease and transmission dynamics starting from the first case on March 9, 2020. A unique collaborative effort between the Pune Municipal Corporation (PMC), a government entity, and the Pune knowledge Cluster (PKC) allowed us to layout a context for outbreak response and intervention. We report here how access to granular data for a metropolitan city with pockets of very high-density populations will help analyze, in real-time, the dynamics of the pandemic and forecasts for better management and control of SARS-CoV-2. Outbreak data analytics resulted in a real-time data visualization dashboard for accurate information dissemination for public access on the epidemic's progress. As government agencies craft testing and vaccination policies and implement intervention strategies to mitigate a second wave, our case study underscores the criticality of data quality and analytics to decode community transmission of COVID-19.

scholarly journals Managing Recurrent Congestion of Subway Network in Peak Hours with Station Inflow Control

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Qingru Zou ◽  
Xiangming Yao ◽  
Peng Zhao ◽  
Fei Dou ◽  
Taoyuan Yang
Keyword(s):  
Large Scale ◽  
Practical Applications ◽  
C Programming Language ◽  
Passenger Flow ◽  
Assignment Model ◽  
C Programming ◽  
Subway System ◽  
And Control ◽  
Internal Relationship

Station inflow control (SIC) is an important and effective method for reducing recurrent congestion during peak hours in the Beijing, Shanghai, and Guangzhou subway systems. This work proposes a practical and efficient method for establishing a static SIC scheme in normal weekdays for large-scale subway networks. First, a traffic assignment model without capacity constraint is utilized to determine passenger flow distributions on the network. An internal relationship between station inflows and section flows is then constructed. Second, capacity bottlenecks are identified by considering the transport capacity of each section. Then, a feedback-based bottleneck elimination strategy is established to search target control stations and determine their control time and control strength. To validate the effectiveness of the proposed approach, a decision support system coded in the C# programming language was developed, and the Beijing subway was used as a case study. The results indicate that the proposed method and tool are capable of practical applications, and the generated SIC plan has better performance over the existing SIC plan. This study provides a practical and useful method for operation agencies to construct SIC schemes in the subway system.

Closed loop identification and control loop reconfiguration: an industrial case study

2001 ◽  
Vol 11 (5) ◽  
pp. 587-599 ◽  
Author(s):  
S. Lakshminarayanan ◽  
G. Emoto ◽  
S. Ebara ◽  
K. Tomida ◽  
Sirish L. Shah
Keyword(s):  
Closed Loop ◽  
Control Loop ◽  
Industrial Case Study ◽  
Closed Loop Identification ◽  
And Control

Examples of energy self-sufficient municipal nutrient removal plants

2011 ◽  
Vol 64 (1) ◽  
pp. 1-6 ◽  
Author(s):  
O. Nowak ◽  
S. Keil ◽  
C. Fimml
Keyword(s):  
Organic Matter ◽  
Particulate Organic Matter ◽  
Nutrient Removal ◽  
Energy Efficient ◽  
Aeration Tank ◽  
Sludge Digestion ◽  
Self Sufficiency ◽  
And Control ◽  
Aerobic Sludge ◽  
Aeration Control

In Austria, two municipal WWTPs (the Strass TP and Wolfgangsee-Ischl TP) operated with nutrient removal and aerobic sludge digestion are now energy self-sufficient. This is the result of a long-standing and on-going optimisation process at both plants including optimal aeration control and control of the aerobic section of the aeration tank to optimise denitrification and prevent degradation of particulate organic matter that should be degraded in the digester. Both TPs are now equipped with energy-efficient CHP units. However, it is maybe more sustainable to use the biogas as bio-methane/bio-fuel than in conventional CHP at the WWTP. It is shown that energy self-sufficiency should be in reach at other municipal WWTPs, too.

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