A simulation study of nonideal mixing effect on the dynamic response of an exothermic CSTR with Cholette’s model

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Chane-Yuan Yang ◽  
Yu-Shu Chien ◽  
Jun-Hong Chou
Keyword(s):  
Transfer Function ◽  
Dynamic Response ◽  
The Other ◽  
System Stability ◽  
Mixing Effect ◽  
Characteristic Roots ◽  
Mixing Parameter ◽  
Perfect Mixing ◽  
And Control ◽  
Inverse Response

Abstract The study of nonideal mixing effect on the dynamic behaviors of CSTRs has very rarely been published in the literature. In this work, Cholette’s model is employed to explore the nonideal mixing effect on the dynamic response of a nonisothermal CSTR. The analysis shows that the mixing parameter n (the fraction of the feed entering the zone of perfect mixing) and m (the fraction of the total volume of the reactor), indeed affect the characteristic roots of transfer function of a real CSTR, which determine the system stability. On the other hand, the inverse response and overshoot response are also affected by the nonideal mixing in a nonisothemal CSTR. These results are of much help for the design and control of a real CSTR.

Application of Cholette’s model in non-ideal mixing CSTR: a simulation study on dynamic behavior

2021 ◽  
Vol 19 (4) ◽  
pp. 341-367
Author(s):  
Chane-Yuan Yang ◽  
Yu-Shu Chien ◽  
Jun-Hong Chou ◽  
Hsing-Ya Li ◽  
Chau Wei Hsieh
Keyword(s):  
Dynamic Behavior ◽  
Chemical Reactor ◽  
Phase Portraits ◽  
Mixing Effect ◽  
State Response ◽  
Ideal Mixing ◽  
Operating Region ◽  
Mixing Parameter ◽  
Perfect Mixing ◽  
And Control

Abstract Non-ideal mixing phenomena are widely found in industrial chemical reactors. In this work we derived the bifurcation formulas for a non-adiabatic CSTR with an irreversible exothermic first order reaction with the non-ideal mixing effect. This is investigated via dynamic behavior simulations based on Chollete’s model. The results show that the non-ideal mixing parameter n (the fraction of the feed entering the perfect mixing zone) determines the variation between six classified regions and dominates the dynamic behavior patterns in the steady-state response diagram. On the other hand, the phase portraits of examples verify the formulas derived in this work. We note that the non-ideal mixing effect has significant importance in CSTR design and control steps. For example, in the safe operating region for an ideal mixing CSTR, non-linear dynamics are obtained by the system under non-ideal mixing conditions (n ≠ 1). The present study has significance and help for chemical reactor design and CSTR control.

Modeling and Control of Torsional Beam Vibrations: A Wave-Based Approach

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
M. Moallem
Keyword(s):  
Transfer Function ◽  
The Other ◽  
Torsional Vibrations ◽  
Inertial Load ◽  
Modeling And Control ◽  
Control Approach ◽  
Infinite Dimensional ◽  
Torsional Beam ◽  
Delay Elements ◽  
And Control

This paper presents a wave-based modeling and control approach for suppressing torsional vibrations of an elastic shaft driven by a motor at one end and an inertial load at the other end. A two-port network model representing the dynamics of torsional displacements is obtained starting from the partial differential equations governing a shaft in torsion. By incorporating appropriate boundary conditions, the infinite dimensional transfer function of the system is obtained. Furthermore, the system is represented by delay elements that can be used for simulation purposes. An inversion-based controller that can be used to suppress vibrations while rotating the shaft according to a specific trajectory is then developed. The performance of the controller is further studied using numerical simulations.

Prothrombin Time Standardization: Report of the Expert Panel on Oral Anticoagulant Control

1979 ◽  
Vol 42 (04) ◽  
pp. 1073-1114 ◽  
Keyword(s):  
Prothrombin Time ◽  
Expert Panel ◽  
The Other ◽  
Rabbit Brain ◽  
Calibration Constant ◽  
Freeze Dried ◽  
The Mean ◽  
Point Of Intersection ◽  
And Control ◽  
Standardization Report

SummaryIn collaborative experiments in 199 laboratories, nine commercial thromboplastins, four thromboplastins held by the National Institute for Biological Standards and Control (NIBS & C), London and the British Comparative Thromboplastin were tested on fresh normal and coumarin plasmas, and on three series of freeze-dried plasmas. One of these was made from coumarin plasmas and the other two were prepared from normal plasmas; in each series, one plasma was normal and the other two represented different degrees of coumarin defect.Each thromboplastin was calibrated against NIBS&C rabbit brain 70/178, from the slope of the line joining the origin to the point of intersection of the mean ratios of coumarin/normal prothrombin times when the ratios obtained with the two thromboplastins on the same fresh plasmas were plotted against each other. From previous evidence, the slopes were calculated which would have been obtained against the NIBS&C “research standard” thromboplastin 67/40, and termed the “calibration constant” of each thromboplastin. Values obtained from the freeze-dried coumarin plasmas gave generally similar results to those from fresh plasmas for all thromboplastins, whereas values from the artificial plasmas agreed with those from fresh plasmas only when similar thromboplastins were being compared.Taking into account the slopes of the calibration lines and the variation between laboratories, precision in obtaining a patient’s prothrombin time was similar for all thromboplastins.

Dry chip feedrate control using online chip moisture

TAPPI Journal ◽  
2018 ◽  
Vol 17 (05) ◽  
pp. 295-305
Author(s):  
Wesley Gilbert ◽  
Ivan Trush ◽  
Bruce Allison ◽  
Randy Reimer ◽  
Howard Mason
Keyword(s):  
Production Rate ◽  
Control Strategy ◽  
Rate Control ◽  
Near Infrared ◽  
Dry Mass ◽  
The Other ◽  
Process Variability ◽  
Moisture Sensor ◽  
Feedback Control Strategy ◽  
And Control

Normal practice in continuous digester operation is to set the production rate through the chip meter speed. This speed is seldom, if ever, adjusted except to change production, and most of the other digester inputs are ratioed to it. The inherent assumption is that constant chip meter speed equates to constant dry mass flow of chips. This is seldom, if ever, true. As a result, the actual production rate, effective alkali (EA)-to-wood and liquor-to-wood ratios may vary substantially from assumed values. This increases process variability and decreases profits. In this report, a new continuous digester production rate control strategy is developed that addresses this shortcoming. A new noncontacting near infrared–based chip moisture sensor is combined with the existing weightometer signal to estimate the actual dry chip mass feedrate entering the digester. The estimated feedrate is then used to implement a novel feedback control strategy that adjusts the chip meter speed to maintain the dry chip feedrate at the target value. The report details the results of applying the new measurements and control strategy to a dual vessel continuous digester.

From Container to Claustrum: Projective Identification in Couples

2014 ◽  
Vol 4 (2) ◽  
Author(s):  
Tamara Feldman
Keyword(s):  
Psychological Health ◽  
Projective Identification ◽  
The Self ◽  
The Other ◽  
Intimate Partners ◽  
And Control ◽  
The Relationship ◽  
As If

This paper is a contribution to the growing literature on the role of projective identification in understanding couples' dynamics. Projective identification as a defence is well suited to couples, as intimate partners provide an ideal location to deposit unwanted parts of the self. This paper illustrates how projective identification functions differently depending on the psychological health of the couple. It elucidates how healthier couples use projective identification more as a form of communication, whereas disturbed couples are inclined to employ it to invade and control the other, as captured by Meltzer's concept of "intrusive identification". These different uses of projective identification affect couples' capacities to provide what Bion called "containment". In disturbed couples, partners serve as what Meltzer termed "claustrums" whereby projections are not contained, but imprisoned or entombed in the other. Applying the concept of claustrum helps illuminate common feelings these couples express, such as feeling suffocated, stifled, trapped, held hostage, or feeling as if the relationship is killing them. Finally, this paper presents treatment challenges in working with more disturbed couples.

scholarly journals Joint Action on cancer iPAAC - building on experience and streamlining recommendations for the future

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
M Jelenc ◽  
T Albreht
Keyword(s):  
Cancer Care ◽  
National Level ◽  
Cancer Control ◽  
Professional Community ◽  
The Other ◽  
Consensus Building ◽  
Good Practices ◽  
Policy Initiatives ◽  
European Code ◽  
And Control

Abstract Background Policy initiatives, proposals and projects often end up proposing solutions and/or measures that are eventually either not or only partially implemented or they are lacking a system, which would consistently evaluate their implementation and/or impact. Good solutions are often not visible enough to the broader professional community and it is important to identify certain outstanding challenges in cancer control and policy. Driven by the need to better use the outputs from projects on cancer policy, European Commission was trying to address two challenges - one was in solving the problems with the implementation and use of the solutions that have already been proposed and the other one in identifying the outstanding challenges in cancer policy. Results We have decided to follow the structure to develop a series of recommendations and examples of good practices at the national level by selected areas. These would be streamlined into a roadmap to support policymakers at the national and EU level in formulating their cancer policies. Three pairs of targeted recommendations have been identified: Cancer prevention, including health promotion, implementation of the European Code Against Cancer and the reshaping and extension of cancer registriesGenomics and immunotherapy in cancerChallenges in cancer care and governance of cancer control Conclusions Multinational collaboration can bring about important consensual solutions, which build on the existing good practices in the countries. This can be combined well with the existing work on specific areas, carried out both internationally and nationally. Consensus building on jointly defined challenges represents a task that appears to be resolved rather pragmatically. Key message It is important that advance in cancer care and control are quickly analysed and that policymakers receive up-to-date recommendations to improve their policies on cancer control.

scholarly journals Metals in Calluna vulgaris, Empetrum nigrum, Festuca vivipara and Thymus praecox ssp. arcticus in the geothermal areas of Iceland

2021 ◽  
Author(s):  
Adam Rajsz ◽  
Bronisław Wojtuń ◽  
Aleksandra Samecka-Cymerman ◽  
Paweł Wąsowicz ◽  
Lucyna Mróz ◽  
...  
Keyword(s):  
Active Sites ◽  
Calluna Vulgaris ◽  
Bioaccumulation Factor ◽  
The Other ◽  
Extreme Situation ◽  
Empetrum Nigrum ◽  
Geothermal Activity ◽  
High Concentrations ◽  
And Control ◽  
Festuca Vivipara

AbstractThis investigation was conducted to identify the content of metals in Calluna vulgaris (family Ericaceae), Empetrum nigrum (family Ericaceae), Festuca vivipara (family Poaceae) and Thymus praecox subsp. arcticus (family Lamiaceae), as well as in the soils where they were growing in eight geothermal heathlands in Iceland. Investigation into the vegetation of geothermal areas is crucial and may contribute to their proper protection in the future and bring more understanding under what conditions the plants respond to an ecologically more extreme situation. Plants from geothermally active sites were enriched with metals as compared to the same species from non-geothermal control sites (at an average from about 150 m from geothermal activity). The enriched metals consisted of Cd, Co, Cu, Fe and Ni in C. vulgaris; Cd, Mn and Ti in E. nigrum; Hg and Pb in F. vivipara; and Cd, Fe and Hg in T. praecox. Notably, C. vulgaris, E. nigrum, F. vivipara and T. praecox had remarkably high concentrations of Ti at levels typical of toxicity thresholds. Cd and Pb (except for C. vulgaris and F. vivipara) were not accumulated in the shoots of geothermal plants. C. vulgaris from geothermal and control sites was characterised by the highest bioaccumulation factor (BF) of Ti and Mn; E. nigrum and F. vivipara by the highest BF of Ti and Cr; and T. praecox by the highest BF of Ti and Zn compared to the other elements. In comparison with the other examined species, F. vivipara from geothermal sites had the highest concentration of Ti in above-ground parts at any concentration of plant-available Ti in soil.

Tolerance and Control. Developing a language policy for an EMI university in Uzbekistan

2020 ◽  
Vol 34 (1) ◽  
pp. 217-237
Author(s):  
Andrew Linn ◽  
Anastasiya Bezborodova ◽  
Saida Radjabzade
Keyword(s):  
Higher Education ◽  
Language Policy ◽  
Control Measures ◽  
The Other ◽  
Language Policies ◽  
Language Ecology ◽  
English Only ◽  
English Medium Instruction ◽  
The One ◽  
And Control

AbstractThis article presents a practical project to develop a language policy for an English-Medium-Instruction university in Uzbekistan. Although the university is de facto English-only, it presents a complex language ecology, which in turn has led to confusion and disagreement about language use on campus. The project team investigated the experience, views and attitudes of over a thousand people, including faculty, students, administrative and maintenance staff, in order to arrive at a proposed policy which would serve the whole community, based on the principle of tolerance and pragmatism. After outlining the relevant language and educational context and setting out the methods and approach of the underpinning research project, the article goes on to present the key findings. One of the striking findings was an appetite for control and regulation of language behaviours. Language policies in Higher Education invariably fall down at the implementation stage because of a lack of will to follow through on their principles and their specific guidelines. Language policy in international business on the other hand is characterised by a control stage invariably lacking in language planning in education. Uzbekistan is a polity used to control measures following from policy implementation. The article concludes by suggesting that Higher Education in Central Asia may stand a better chance of seeing through language policies around English-Medium Instruction than, for example, in northern Europe, based on the tension between tolerance on the one hand and control on the other.

scholarly journals The Repercussion of Ai Chi on Aged People’s Balance

2014 ◽  
Vol 4 (3) ◽  
pp. 247-256
Author(s):  
Pablo Javier Olabe Sánchez ◽  
Andrés Martínez-Almagro Andreo
Keyword(s):  
Fall Prevention ◽  
Controlled Trial ◽  
Intervention Group ◽  
The Other ◽  
Control Group ◽  
Aged People ◽  
Randomized Controlled ◽  
Risk Of Fall ◽  
And Control ◽  
Positive Effect

To practice strength and balance activities are shown as useful tools to fall prevention by diverse metanalysis. On the other side, aquatic environment offers interesting properties for a therapeutic reeducation, being the Ai Chi one of its applications. Aim: To evaluate the repercussion of an Ai Chi programme on aged people’s balance. Method: A randomized controlled trial was developed comparing two groups formed by aged people with risk of fall according to the Timed Up & Go test. Intervention Group (IG) followed twelve Ai Chi sessions combined with their thermal programme; and Control Group (CG) just followed the thermal programme. Both groups spent two weeks in the Balneario of Archena (Murcia, Spain). Results: Both groups improve their balance; however, only the IG reached the non-risk of fall from the Timed Up & Go test. Conclusions: The combination of Ai Chi sessions and a thermal programme had a positive effect on aged people’s balance, showing a therapeutic and clinical relevance.

scholarly journals Artveillance: At the Crossroads of Art and Surveillance

2009 ◽  
Vol 7 (2) ◽  
pp. 175-186 ◽  
Author(s):  
Andrea Mubi Brighenti
Keyword(s):  
Social Control ◽  
The Other ◽  
Contemporary Society ◽  
Other Hand ◽  
Surveillance Society ◽  
The One ◽  
And Control

In this article I review a series of artworks, artistic performances and installations that deal with the topic of surveillance. My aim is twofold. On the one hand, I want to look comparatively at how different artists interrogate, question, quote, or critise surveillance society. On the other hand, I take these artistic actions as themselves symptomatic of the ways in which surveillance interrogates contemporary society. In other words, my claim is that surveillance does not simply produce substantive social control and social triage, it also contributes to the formation of an ideoscape and a collective imagery about what security, insecurity, and control are ultimately about, as well as the landscape of moods a surveillance society like ours expresses.

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