scholarly journals Chemical Clogging and Evolution of Head Losses in Steel Slag Filters Used for Phosphorus Removal

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1517
Author(s):  
Dominique Claveau-Mallet ◽  
Yves Comeau
Keyword(s):  
Hydraulic Conductivity ◽  
Steel Slag ◽  
Pressure Head ◽  
Effective Porosity ◽  
Future Research ◽  
Head Losses ◽  
Heterogeneous Precipitation ◽  
Two Factors ◽  
Granular Filters ◽  
Inlet Zone

The objective of this study was to propose a conceptual model of clogging in alkaline granular filters. Two slag columns were operated for 600 days and monitored using piezometers and tracer tested at regular intervals. The type of influent (organic or inorganic) affected the loss of effective porosity in the filters. Well organized and loose crystal structures were observed by scanning electron microscopy in columns with inorganic and organic influents, respectively. It was postulated that the formation of crystals in unorganized structures results in confined voids that are not accessible for water flow, thus accelerating porosity loss. The effect of the combination of chemical clogging and biofilm on the porosity loss is higher than the effect of these two factors separately. The Kozeny-Carman equation for hydraulic conductivity could not efficiently predict the evolution of head losses in the column fed with an inorganic influent. The crystal structure and connectivity in the presence of homogeneous or heterogeneous precipitation are concepts that could improve predictions of hydraulic conductivity. The results of this study highlighted the importance of the inlet zone on the development of pressure head in alkaline granular filters. Future research on clogging should focus on precipitation mechanisms in the inlet zone and on the design of the feeding system.

Questions

2018 ◽  
Author(s):  
James L. Gibson ◽  
Michael J. Nelson
Keyword(s):  
United States ◽  
African Americans ◽  
Supreme Court ◽  
Legal System ◽  
Public Support ◽  
The United States ◽  
Future Research ◽  
White Americans ◽  
Two Factors ◽  
The U.S

We have investigated the differences in support for the U.S. Supreme Court among black, Hispanic, and white Americans, catalogued the variation in African Americans’ group attachments and experiences with legal authorities, and examined how those latter two factors shape individuals’ support for the U.S. Supreme Court, that Court’s decisions, and for their local legal system. We take this opportunity to weave our findings together, taking stock of what we have learned from our analyses and what seem like fruitful paths for future research. In the process, we revisit Positivity Theory. We present a modified version of the theory that we hope will guide future inquiry on public support for courts, both in the United States and abroad.

Knowledge Sharing, Social Relationships, and Contextual Performance

2015 ◽  
Vol 27 (2) ◽  
pp. 58-73 ◽  
Author(s):  
Jianping Peng ◽  
Jing Quan ◽  
Guoying Zhang ◽  
Alan J. Dubinsky
Keyword(s):  
Knowledge Sharing ◽  
Social Relationships ◽  
Positive Impact ◽  
Contextual Performance ◽  
Interpersonal Interaction ◽  
Future Research ◽  
Core Competitiveness ◽  
Two Factors ◽  
Sustained Innovation ◽  
It Training

A firm's core competitiveness results primarily from its ability to innovate. Knowledge sharing plays an important role in promoting sustained innovation. This research examines two factors that enable employee knowledge sharing. Using responses from a questionnaire that was distributed to professionals in a research and development (R&D) department of a Chinese commercial elevator firm, the investigation examines whether social relationships and contextual performance influence knowledge sharing through the moderating effect of employee IT competence. Study findings reveal that social relationships—which include both the degree of centrality of the employee's social network and frequency of interpersonal interaction—and employee contextual performance have a significant positive impact on knowledge sharing. This association, however, is found to be positively moderated by employee IT competence. The findings provide managerial and future research insights pertaining to promoting knowledge sharing by enhancing employee social relationships, rewarding contextual performance, and providing regular IT training for employees.

scholarly journals Soil water management problems using fuzzy arithmetic

2013 ◽  
Vol 11 (4) ◽  
pp. 556-565
Keyword(s):  
Hydraulic Conductivity ◽  
Uncertain Data ◽  
Triangular Fuzzy Number ◽  
Effective Porosity ◽  
Specific Yield ◽  
Fuzzy Arithmetic ◽  
Two Dimensional ◽  
Fuzzy Analysis ◽  
Management Problems ◽  
Α Level

Drainage management problems are usually very hard to simulate due to the uncertainty of the hydraulic parameters involved. Fuzzy analysis is one of the available tools that can be used for such problems, involving uncertain data. A fuzzy analysis approach usually involves the consideration of several α-level cuts and an analytical approach or an explicit scheme approach for the PDE's discretization. Several application examples of this approach are listed in the literature, including uncertainty in hydraulic conductivity, specific yield, transmissivities, porosities, dispersivities, and deoxygenation rate coefficient. A methodology for the simulation of drainage problem having vague values of hydraulic parameters is introduced in this paper, and an analytical solution for a two-dimensional drainage application is presented. The two-dimensional problem of drainage is handled using fuzzy analysis by defining the hydraulic conductivity K as a triangular fuzzy number (TFN). The method of interval analysis is used in all the α-level cut examples. A solution is obtained using eleven α-level cuts and also solutions for two, three, and five α-level cuts are presented. Trials for different values of effective porosity are also performed. Finally conclusions on the necessary number of α-cuts utilized for drainage problems are drawn.

scholarly journals The moderating effects of Social Desirability responding on the criterion-related validity of self-report personality inventory

2015 ◽  
Vol 28 (2) ◽  
pp. 151-172
Author(s):  
JaeYoon Chang ◽  
Sanghee Nam
Keyword(s):  
Impression Management ◽  
Social Desirability ◽  
Helping Behavior ◽  
Self Report ◽  
Performance Criteria ◽  
Future Research ◽  
Moderating Effects ◽  
Moderation Effects ◽  
Host Country Nationals ◽  
Two Factors

This study aimed to examine how social desirability responding(SDR) affects the criterion-related validity of self-reported personality. Specifically, this study examined how SDR, impression management(IM) and self deceptive enhancement(SDE) can take distinct effects on criteria when personality traits of 91 expatriates such as empathy, cooperation, and friendliness predict their performance criteria. Although previous studies suggested either suppression or moderation effects of SDR, the results indicated that there was no suppression effects but statistically significant moderation effects of SDE on the link between each of some predictors(empathy and cooperation) and expatriate’s negative emotional expression and helping behavior in organization rated by peers(host country nationals). However, such effects were not supported in case of IM. The importance of specifying two factors of SDR and suggestions for the future research were discussed.

scholarly journals The referential grain size and effective porosity in the Kozeny–Carman model

2016 ◽  
Author(s):  
K. Urumović ◽  
K. Urumović Sr.
Keyword(s):  
Grain Size ◽  
Hydraulic Conductivity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Effective Porosity ◽  
Critical Conditions ◽  
Saturated Porous Media ◽  
New Developments ◽  
Mean Grain Size

Abstract. In this paper, the results of permeability and specific surface area analyses as functions of granulometric composition of various sediments (from silty clays to very well-graded gravels) are presented. The effective porosity and the referential grain size are presented as fundamental granulometric parameters expressing an effect of the forces operating on fluid movement through the saturated porous media. This paper suggests procedures for calculating referential grain size and determining effective (flow) porosity, which result in parameters that reliably determine the specific surface area and permeability. These procedures ensure the successful application of the Kozeny–Carman model up to the limits of validity of Darcy’s law. The value of effective porosity in the referential mean grain size function was calibrated within the range of 1.5 μm to 6.0 mm. The reliability of the parameters applied in the KC model was confirmed by a very high correlation between the predicted and tested hydraulic conductivity values (R2=0.99 for sandy and gravelly materials; R2=0.70 for clayey-silty materials). The group representation of hydraulic conductivity (ranging from 10–12 m/s up to 10–2 m/s) presents a coefficient of correlation of R2=0.97 for a total of 175 samples of various deposits. These results present new developments in the research of the effective porosity, the permeability and the specific surface area distributions of porous materials. This is important because these three parameters are critical conditions for successful groundwater flow modeling and contaminant transport. Additionally, from a practical viewpoint, it is very important to identify these parameters swiftly and very accurately.

An Investigation of Factors Influencing the Use of Computer-Related Audit Procedures

2009 ◽  
Vol 23 (1) ◽  
pp. 97-118 ◽  
Author(s):  
Diane Janvrin ◽  
James Bierstaker ◽  
D. Jordan Lowe
Keyword(s):  
Risk Assessment ◽  
Firm Size ◽  
Business Processes ◽  
Internal Controls ◽  
Future Research ◽  
Audit Firm ◽  
Factors Influencing ◽  
Big 4 ◽  
Two Factors ◽  
Client System

ABSTRACT: We provide data on the extent to which computer-related audit procedures are used and whether two factors, control risk assessment and audit firm size, influence computer-related audit procedures use. We used a field-based questionnaire to collect data from 181 auditors representing Big 4, national, regional, and local firms. Results indicate that computer-related audit procedures are generally used when obtaining an understanding of the client system and business processes and testing computer controls. Furthermore, 42.9 percent of participants indicate that they relied on internal controls; however, this percentage increases significantly for auditors at Big 4 firms. Finally, our results raise questions for future research regarding computer-related audit procedure use.

Upscaling and regionalizing hydraulic conductivity and effective porosity at watershed scale in deeply weathered crystalline aquifers

2012 ◽  
Vol 416-417 ◽  
pp. 83-97 ◽  
Author(s):  
B. Dewandel ◽  
J.C. Maréchal ◽  
O. Bour ◽  
B. Ladouche ◽  
S. Ahmed ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Effective Porosity ◽  
Watershed Scale

Countering Reactance in Crisis Communication: Incorporating Positive Emotions via Social Media

2017 ◽  
Vol 57 (3) ◽  
pp. 352-369 ◽  
Author(s):  
Jie Xu ◽  
Yiye Wu
Keyword(s):  
Social Media ◽  
Crisis Communication ◽  
Positive Emotions ◽  
Mediation Effect ◽  
Amazon Mechanical Turk ◽  
Future Research ◽  
Reactance Theory ◽  
Two Factors ◽  
Managerial Implications ◽  
Psychological Reactance Theory

Based on the psychological reactance theory, this study examined the effect of incorporating sympathy via social media on countering reactance in crisis communication. The study employed a 2 (expressing sympathy: yes vs. no) × 2 (medium: Twitter vs. news release) between-subject experimental design. Two hundred and fifty-three ( N = 253) American consumers recruited from Amazon Mechanical Turk participated in this online experiment. Results indicated that using Twitter and expressing sympathy significantly lowered reactance. There was no interaction effect between the two factors, such that their influence on reactance was not contingent on one another. There was a partial yet significant mediation effect of reactance between medium and two outcomes (perceived crisis responsibility and organizational reputation). There was no mediation effect of reactance between sympathy expressed and two outcomes. The theoretical and managerial implications were discussed, as well as limitations and suggestions for future research.

scholarly journals ICTs and Music in Special Learning Disabilities

2016 ◽  
Vol 4 (3) ◽  
pp. 12 ◽  
Author(s):  
Athanasios Drigas ◽  
Paraskevi Theodorou
Keyword(s):  
Information And Communication Technologies ◽  
Learning Difficulties ◽  
Communication Technologies ◽  
Research Field ◽  
Future Research ◽  
Research Perspectives ◽  
Two Factors ◽  
Information And Communication ◽  
Access To Knowledge

Τhis study is a critical review of published scientific literature on the use of Information and Communication Technologies (ICT), Virtual Reality, multimedia, music and their applications in children with special learning difficulties.  Technology and music are two factors that are recognized as tools which ensure quality of life, success and access to knowledge and learning resources. In the following papers of the last decade (2006-2015) are proposed models of music therapy for students with special learning difficulties in a psycho educational setting. There are also defined future research perspectives concerning the applications of technology in this particular research field.

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