Influence of solid retention time on the rheology of MBR sludge

2007 ◽  
Vol 56 (8) ◽  
pp. 151-159 ◽  
Author(s):  
C. Giordano ◽  
A. Pollice ◽  
G. Laera ◽  
D. Saturno ◽  
G. Mininni
Keyword(s):  
Retention Time ◽  
Apparent Viscosity ◽  
Biomass Concentration ◽  
Rheological Behaviour ◽  
Solid Material ◽  
Design Parameters ◽  
Rheological Characterization ◽  
Solid Retention Time ◽  
The One ◽  
Definition Of

The rheological characterization is of crucial importance in sludge management both for biomass dewatering and stabilization purposes and for the definition of design parameters for sludge handling operations. The sludge retention time (SRT) has a significant influence on biomass properties in biological wastewater treatment systems and in particular in membrane bioreactors (MBR). The aim of this work is to compare the rheological behaviour of the biomass in a membrane bioreactor operated under different SRT. A bench scale MBR was operated for four years under the same conditions except for the SRT, that ranged from 20 days to complete sludge retention. The rheological properties were measured over time and the apparent viscosity was correlated with the concentration of solid material under equilibrium conditions. The three models most commonly adopted for rheological simulations were evaluated and compared in terms of their parameters. Steady state average values of these parameters were related to the equilibrium biomass concentration (MLSS). The models were tested to select the one better fitting the experimental data in terms of Mean Root Square Error (MRSE). The relationship between the apparent viscosity and the shear rate, as a function of solid concentration, was determined and proposed.

scholarly journals Assessment of Membrane Bioreactor in Treating Spent Sulfidic Caustic Wastewater: Effects of Organic Biomass Concentration and Solid Retention Time

2017 ◽  
Vol 19 ◽  
pp. 102 ◽  
Author(s):  
Noor Sabrina Ahmad Mutamim ◽  
Zainura Zainon Noor
Keyword(s):  
Retention Time ◽  
Membrane Bioreactor ◽  
Chemical Engineering ◽  
Membrane Surface ◽  
Biomass Concentration ◽  
High Strength ◽  
Suspended Solid ◽  
Solid Retention Time ◽  
Engineering Research ◽  
Spent Caustic

<p>This paper presents a study on the performance of an Aerobic Submerged u-shaped membrane bioreactor (ASMBR) in treating sulfidic spent caustic (SSC) in terms of mixed liquor suspended solid (MLSS) concentration and solid retention time (SRT). SSC wastewater is categorized as high strength wastewater and consists of high inorganic and organic matter. U-shape membrane bioreactors have a higher tendency to foul compared to other types of MBR. MLSS concentration and SRT are the major parameters when operating membrane bioreactor. In this study, COD removal recorded reduction of more than 95% for average MLSS concentration runs and 90% for SRTs runs. Meanwhile, sulfide was removed 99%, and formed up to 79% of sulfate. The biofouling for MLSS concentration and SRTs were observed through TMP rate change and TMP average performance, TMP trend and SMP and EPS trends. Biocake layer and biolayer deposited on membrane surface was found influenced by biomass, the inert particulate biomass products accumulating in the reactor.</p><p>Chemical Engineering Research Bulletin 19(2017) 102-110</p>

scholarly journals Prediction of Speech Onset by Micro-Electrocorticography of the Human Brain

2021 ◽  
pp. 2150025
Author(s):  
Emanuela Delfino ◽  
Aldo Pastore ◽  
Elena Zucchini ◽  
Maria Francisca Porto Cruz ◽  
Tamara Ius ◽  
...  
Keyword(s):  
Motor Preparation ◽  
Gamma Oscillations ◽  
Design Parameters ◽  
Technological Advances ◽  
High Gamma ◽  
Highly Correlated ◽  
The One ◽  
Definition Of ◽  
Key Steps ◽  
Physiological Markers

Recent technological advances show the feasibility of offline decoding speech from neuronal signals, paving the way to the development of chronically implanted speech brain computer interfaces (sBCI). Two key steps that still need to be addressed for the online deployment of sBCI are, on the one hand, the definition of relevant design parameters of the recording arrays, on the other hand, the identification of robust physiological markers of the patient’s intention to speak, which can be used to online trigger the decoding process. To address these issues, we acutely recorded speech-related signals from the frontal cortex of two human patients undergoing awake neurosurgery for brain tumors using three different micro-electrocorticographic ([Formula: see text]ECoG) devices. First, we observed that, at the smallest investigated pitch (600[Formula: see text][Formula: see text]m), neighboring channels are highly correlated, suggesting that more closely spaced electrodes would provide some redundant information. Second, we trained a classifier to recognize speech-related motor preparation from high-gamma oscillations (70–150[Formula: see text]Hz), demonstrating that these neuronal signals can be used to reliably predict speech onset. Notably, our model generalized both across subjects and recording devices showing the robustness of its performance. These findings provide crucial information for the design of future online sBCI.

Understanding functional illiteracy from a policy, adult education, and cognition point of view: Towards a joint referent framework

2019 ◽  
Vol 30 (2) ◽  
pp. 109-122
Author(s):  
Aleksandar Bulajić ◽  
Miomir Despotović ◽  
Thomas Lachmann
Keyword(s):  
Adult Education ◽  
Operational Definition ◽  
Literacy Skills ◽  
Point Of View ◽  
Industrialized Countries ◽  
Functional Illiteracy ◽  
Scale Levels ◽  
Components Of Reading ◽  
The One ◽  
Definition Of

Abstract. The article discusses the emergence of a functional literacy construct and the rediscovery of illiteracy in industrialized countries during the second half of the 20th century. It offers a short explanation of how the construct evolved over time. In addition, it explores how functional (il)literacy is conceived differently by research discourses of cognitive and neural studies, on the one hand, and by prescriptive and normative international policy documents and adult education, on the other hand. Furthermore, it analyses how literacy skills surveys such as the Level One Study (leo.) or the PIAAC may help to bridge the gap between cognitive and more practical and educational approaches to literacy, the goal being to place the functional illiteracy (FI) construct within its existing scale levels. It also sheds more light on the way in which FI can be perceived in terms of different cognitive processes and underlying components of reading. By building on the previous work of other authors and previous definitions, the article brings together different views of FI and offers a perspective for a needed operational definition of the concept, which would be an appropriate reference point for future educational, political, and scientific utilization.

Democracy and Political Culture

2019 ◽  
Author(s):  
Ross McKibbin
Keyword(s):  
Political Culture ◽  
Case Studies ◽  
Social System ◽  
Political System ◽  
Democratic Politics ◽  
Social Structures ◽  
The Political ◽  
The Subject ◽  
The One ◽  
Definition Of

This book is an examination of Britain as a democratic society; what it means to describe it as such; and how we can attempt such an examination. The book does this via a number of ‘case-studies’ which approach the subject in different ways: J.M. Keynes and his analysis of British social structures; the political career of Harold Nicolson and his understanding of democratic politics; the novels of A.J. Cronin, especially The Citadel, and what they tell us about the definition of democracy in the interwar years. The book also investigates the evolution of the British party political system until the present day and attempts to suggest why it has become so apparently unstable. There are also two chapters on sport as representative of the British social system as a whole as well as the ways in which the British influenced the sporting systems of other countries. The book has a marked comparative theme, including one chapter which compares British and Australian political cultures and which shows British democracy in a somewhat different light from the one usually shone on it. The concluding chapter brings together the overall argument.

An LQ Approach to Active Control of Vibrations in Helicopters

1996 ◽  
Vol 118 (3) ◽  
pp. 482-488 ◽  
Author(s):  
Sergio Bittanti ◽  
Fabrizio Lorito ◽  
Silvia Strada
Keyword(s):  
Optimal Control ◽  
Active Control ◽  
Linear Quadratic ◽  
Control Effort ◽  
Vibration Effect ◽  
Suitable Definition ◽  
Lq Optimal Control ◽  
The One ◽  
Definition Of ◽  
And Control

In this paper, Linear Quadratic (LQ) optimal control concepts are applied for the active control of vibrations in helicopters. The study is based on an identified dynamic model of the rotor. The vibration effect is captured by suitably augmenting the state vector of the rotor model. Then, Kalman filtering concepts can be used to obtain a real-time estimate of the vibration, which is then fed back to form a suitable compensation signal. This design rationale is derived here starting from a rigorous problem position in an optimal control context. Among other things, this calls for a suitable definition of the performance index, of nonstandard type. The application of these ideas to a test helicopter, by means of computer simulations, shows good performances both in terms of disturbance rejection effectiveness and control effort limitation. The performance of the obtained controller is compared with the one achievable by the so called Higher Harmonic Control (HHC) approach, well known within the helicopter community.

scholarly journals Beyond Classical Definition: The Non-definition of Gamification

2021 ◽  
Vol 2 (2) ◽  
Author(s):  
Mario S. Staller ◽  
Swen Koerner
Keyword(s):  
Empirical Investigation ◽  
Working Life ◽  
Pedagogical Practice ◽  
Police Recruits ◽  
Design Elements ◽  
The Subject ◽  
Anchor Points ◽  
The One ◽  
Definition Of ◽  
Game Elements

AbstractGamification is regularly defined as the use of game elements in non-gaming contexts. However, discussions in the context of the pedagogical value of gamification suggest controversies on various levels. While on the one hand, the potential is seen in the design of joyful learning environments, critics point out the pedagogical dangers or the problems related to optimizing working life. It becomes apparent that the assumptions guiding action on the subject matter of gamification in educational contexts differ, which leads to different derivations for pedagogical practice—but also allows for different perspectives on initially controversial positions. Being aware of these assumptions is the claim of a reflexive pedagogy. With regard to the pedagogical use of gamifying elements and their empirical investigation, there are three main anchor points to consider from a reflexive stance: (a) the high context-specificity of the teaching undertaken and (b) the (non-)visibility of the design elements and (c) the (non-)acceptance of the gamified elements by the students. We start by providing a discussion of the definitional discourse on what is understood as gamification leading to our argument for a non-definition of gamification. We describe the potential of this non-definition of gamification and exemplify its use in a gamified concept of teaching police recruits professional reflexivity. The concept features the narrative of a potential crime that has been undertaken and that students decide for themselves if they want to engage with it.

scholarly journals The contribution of resident physicians to hospital productivity

2021 ◽  
Author(s):  
Maria J. Perez-Villadóniga ◽  
Ana Rodriguez-Alvarez ◽  
David Roibas
Keyword(s):  
Production Functions ◽  
Weighted Sum ◽  
Main Hypothesis ◽  
Resident Physicians ◽  
Suitable Parameter ◽  
Functional Forms ◽  
The One ◽  
Definition Of ◽  
Hospital Productivity ◽  
Natural Hypothesis

AbstractResident physicians play a double role in hospital activity. They participate in medical practices and thus, on the one hand, they should be considered as an input. Also, they are medical staff in training and, on the other hand, must be considered as an output. The net effect on hospital activities should therefore be empirically determined. Additionally, when considering their role as active physicians, a natural hypothesis is that resident physicians are not more productive than senior ones. This is a property that standard logarithmic production functions (including Cobb–Douglas and Translog functional forms) cannot verify for the whole technology set. Our main contribution is the development of a Translog modification, which implies the definition of the input “doctors” as a weighted sum of senior and resident physicians, where the weights are estimated from the empirical application. This modification of the standard Translog is able, under suitable parameter restrictions, to verify our main hypothesis across the whole technology set while determining if the net effect of resident physicians in hospitals’ production should be associated to an output or to an input. We estimate the resulting output distance function frontier with a sample of Spanish hospitals. Our findings show that the overall contribution of resident physicians to hospitals’ production allows considering them as an input in most cases. In particular, their average productivity is around 37% of that corresponding to senior physicians.

Ex Meritis Praevisis: Predestination, Grace, and Free Will in intra-Jesuit Controversies (1587-1613)

2020 ◽  
Vol 7 (1) ◽  
pp. 111-150
Author(s):  
Eleonora Rai
Keyword(s):  
Free Will ◽  
Society Of Jesus ◽  
Modern Age ◽  
Sovereign Authority ◽  
Theological Debate ◽  
The One ◽  
Definition Of ◽  
The Relationship ◽  
God’S Foreknowledge ◽  
Catholic Theological

AbstractThis article retraces the intra-Jesuit theological debates on the theology of salvation, including the relationship between the elements of predestination, God’s foreknowledge, Grace, and free will, in the delicate passage between the sixteenth and the seventeenth centuries, and within the debates on Augustine’s theological legacy. Specifically, it explores the Flemish Jesuit Leonard Lessius’ theology and the discussions raised by it within the Society of Jesus, in order to show how soteriology has been central in the process of self-definition of the Jesuit identity in the Early Modern Age. This is particularly clear from the internal debates developed between Lessius, on the one hand, and General Claudio Acquaviva and curial theologian Roberto Bellarmino, on the other hand. Not only does the article investigate little known aspects of intra-Catholic theological debate in the post Tridentine period, but it also shows how deep pastoral and moral concerns strongly contributed to the rise of Lessius’ open-minded theology of salvation, which seemed to deprive God’s sovereign authority in favour of humankind’s free will, and human agency in the process of salvation.

scholarly journals Exploring International and Inter-Sector Differences of Social Enterprises in the UK and India

2021 ◽  
Vol 13 (11) ◽  
pp. 5870
Author(s):  
Philipp Kruse
Keyword(s):  
Social Entrepreneurship ◽  
Social Enterprise ◽  
Social Enterprises ◽  
Future Research ◽  
Shape Features ◽  
Qualitative And Quantitative ◽  
Clear Cut ◽  
The One ◽  
Definition Of ◽  
The Uk

Social Entrepreneurship (SE) describes a new entrepreneurial form combining the generation of financial and social value. In recent years, research interest in SE increased in various disciplines with a particular focus on the characteristics of social enterprises. Whereas a clear-cut definition of SE is yet to be found, there is evidence that culture and economy affect and shape features of SE activity. In addition, sector-dependent differences are supposed. Building on Institutional Theory and employing a mixed qualitative and quantitative approach, this study sheds light on the existence of international and inter-sector differences by examining 161 UK and Indian social enterprises. A content analysis and analyses of variance were employed and yielded similarities as well as several significant differences on an international and inter-sector level, e.g., regarding innovativeness and the generation of revenue. The current study contributes to a more nuanced picture of the SE landscape by comparing social enterprise characteristics in a developed and a developing country on the one hand and different sectors on the other hand. Furthermore, I highlight the benefits of jointly applying qualitative and quantitative methodologies. Future research should pay more attention to the innate heterogeneity among social enterprises and further consolidate and extend these findings.

Towards a computational theory of social groups: A finite set of cognitive primitives for representing any and all social groups in the context of conflict

2021 ◽  
pp. 1-62
Author(s):  
David Pietraszewski
Keyword(s):  
Social Group ◽  
Group Representation ◽  
Social Groups ◽  
Study Groups ◽  
Human Mind ◽  
Computational Theory ◽  
Mistaken Belief ◽  
Finite Set ◽  
The One ◽  
Definition Of

Abstract We don't yet have adequate theories of what the human mind is representing when it represents a social group. Worse still, many people think we do. This mistaken belief is a consequence of the state of play: Until now, researchers have relied on their own intuitions to link up the concept social group on the one hand, and the results of particular studies or models on the other. While necessary, this reliance on intuition has been purchased at considerable cost. When looked at soberly, existing theories of social groups are either (i) literal, but not remotely adequate (such as models built atop economic games), or (ii) simply metaphorical (typically a subsumption or containment metaphor). Intuition is filling in the gaps of an explicit theory. This paper presents a computational theory of what, literally, a group representation is in the context of conflict: it is the assignment of agents to specific roles within a small number of triadic interaction types. This “mental definition” of a group paves the way for a computational theory of social groups—in that it provides a theory of what exactly the information-processing problem of representing and reasoning about a group is. For psychologists, this paper offers a different way to conceptualize and study groups, and suggests that a non-tautological definition of a social group is possible. For cognitive scientists, this paper provides a computational benchmark against which natural and artificial intelligences can be held.

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