scholarly journals The Impact of Selected Pretreatment Procedures on Iron Dissolution from Metallic Iron Specimens Used in Water Treatment

2019 ◽  
Vol 11 (3) ◽  
pp. 671 ◽  
Author(s):  
Rui Hu ◽  
Arnaud Ndé-Tchoupé ◽  
Mesia Lufingo ◽  
Minhui Xiao ◽  
Achille Nassi ◽  
...  

Studies were undertaken to determine the reasons why published information regarding the efficiency of metallic iron (Fe0) for water treatment is conflicting and even confusing. The reactivity of eight Fe0 materials was characterized by Fe dissolution in a dilute solution of ethylenediaminetetraacetate (Na2–EDTA; 2 mM). Both batch (4 days) and column (100 days) experiments were used. A total of 30 different systems were characterized for the extent of Fe release in EDTA. The effects of Fe0 type (granular iron, iron nails and steel wool) and pretreatment procedure (socking in acetone, EDTA, H2O, HCl and NaCl for 17 h) were assessed. The results roughly show an increased iron dissolution with increasing reactive sites (decreasing particle size: wool > filings > nails), but there were large differences between materials from the same group. The main output of this work is that available results are hardly comparable as they were achieved under very different experimental conditions. A conceptual framework is presented for future research directed towards a more processed understanding.

2020 ◽  
Vol 17 (3) ◽  
pp. 493-505 ◽  
Author(s):  
Haoze Li ◽  
Bingxiang Huang ◽  
Qingying Cheng ◽  
Xinglong Zhao

Abstract Proppant placement concentration, particle size and creep time are important factors that affect the embedment of proppant into coal. Based on multistage creep, an orthogonal test is conducted, and an optimal proppant scheme for different closure stresses obtained. The results show that with increased proppant placement concentration, the number of coal fractures increases and the elastic modulus of the fracture area decreases. As the proppant particle size decreases, the plasticity of fracture-proppant assemblies increases gradually. The yield limit is highest when the particle size is 20/40 mesh. During the proppant embedding process, localization or uneven distribution of proppant results in tensile stress parallel to the fracture surface, which induces tensile fracture in the coal. In the fracture-proppant assembly areas, proppant fractures are severe and yield lines appear. As proppant concentration increases, more energy is accumulated during the proppant compaction stage, resulting in energy release producing craters and crevasses. The energy released also causes increased stress in the proppant-coal contact area and fracturing to the coal mass. The longer the creep time, the weaker the impact and the smaller is fluctuation. Moreover, we find that the orthogonal test can effectively analyze the importance of each parameter. Proppant placement concentration was found to have the highest influence on the process of proppant embedding into coal, followed by particle size and then time. Under experimental conditions, the lowest proppant-embedded value in coal samples was observed with proppant placement concentration of 2 kg m−2 and particle size of 20/40 mesh.


Author(s):  
Kerri M Lehman ◽  
Kevin L Burke ◽  
Randall Martin ◽  
Jennifer Sultan ◽  
Daniel R Czech

AbstractThe ability to effectively cope with stress has been demonstrated to be an important factor in warding off potential physical disease and psychological distress. Responses to stressful events have been shown to greatly vary across individuals. Research has shown that intervening variables, such as cognitive appraisals of stressful events, can markedly affect the amount of stress (e.g., mood disturbance, anxiety, changes in neurotransmitter concentrations, suppression of immune system functioning) individuals experience. One such intervening variable, productive humor, was hypothesized to have a positive stress-moderating effect.Four different experimental conditions were used to assess the impact of a stressful situation on mood and anxiety state. Two conditions had subjects produce a humorous narrative in response to the stressful situation. One of these conditions included an instructional video on the use of productive humor. A third condition had subjects produce an intellectual narrative, while a fourth condition had subjects produce no narrative. The humorous narrative conditions were hypothesized to lead to the greatest moderation in stress (i.e., mood and anxiety).In the humorous narrative (without training) condition, subjects who were more successful at producing the narratives showed significantly more moderated changes in mood and anxiety levels pre-task to post-task. These changes were not significantly different from the intellectual or no narrative conditions. The significant difference found between high versus low humorous narrative producers may be accounted for in terms of success versus non-success at completing the experimental task.Finally, among subjects with initially high pre-task mood or anxiety levels and high tendencies to use productive humor, successful performance of some type of a verbal, cognitive task (i.e., humorous or intellectual narrative) was found to be more beneficial in moderating the effects of stress versus silence. These latter findings were based on patterns of results from post hoc analyses with small sample sizes, thus suggesting the need for future research along similar lines.


10.2196/15772 ◽  
2020 ◽  
Vol 22 (3) ◽  
pp. e15772
Author(s):  
Daniel Drewniak ◽  
Andrea Glässel ◽  
Martina Hodel ◽  
Nikola Biller-Andorno

Background Patient narratives are illustrative, individual accounts of patients’ experiences with certain health conditions. Web-based patient narratives have become widely available on the internet and in social media, as part of electronically available patient decision aids or Web-based databases. In recent years, the role of patient narratives as a source of information, insight, and support for both health care users and providers has increasingly been emphasized. Although the potential impact of patient stories has high immediate plausibility, it is of interest to know if this impact can be captured in quantitative studies. Objective This review aimed to evaluate whether research-generated Web-based patient narratives have quantifiable risks or benefits for (potential) patients, relatives, or health care professionals. Methods We searched the following databases from August 2017 to March 2019: Medical Literature Analysis and Retrieval System Online, PsycInfo, Sociological Abstracts, Web of Science, and EMBASE. Titles and abstracts of the retrieved studies were reviewed and assessed for the inclusion and exclusion criteria. Papers were included if they studied the following: (1) (potential) patients, relatives, or health care professionals; (2) the effects of Web-based patient narratives that were generated scientifically (eg, through qualitative research methods); and (3) were quantitative studies. Furthermore, 2 authors independently performed an assessment of the quality of the included studies using a validated checklist. Results Of 4226 documents, 17 studies met the inclusion criteria. The studies investigated 10 different sources of Web-based patient narratives. Sample sizes ranged from 23 to 2458. The mean score of the quality assessment was 82.6 (range 61-100). Effects regarding five different purposes were identified as follows: provide information, engage, model behavior, persuade, and comfort. We found positive effects in every category and negative effects in one category (persuade). Several of the reported effects are rather small or were identified under specific experimental conditions. Conclusions Patient narratives seem to be a promising means to support users in improving their understanding of certain health conditions and possibly to provide emotional support and have an impact on behavioral changes. There is limited evidence for beneficial effects on some outcomes. However, narratives are characterized by considerable heterogeneity and the investigated outcomes are hardly comparable with each other, which makes the overall judgment difficult. As there are numerous possible measures and purposes of narratives, quantifying the impact of Web-based patient narratives remains a challenge. Future research is needed to define the optimal standards for quantitative approaches to narrative-based interventions.


2021 ◽  
Vol 12 ◽  
Author(s):  
Sven van As ◽  
Debby G. J. Beckers ◽  
Sabine A. E. Geurts ◽  
Michiel A. J. Kompier ◽  
Masud Husain ◽  
...  

Research suggests that cognitive fatigue has a negative impact on physical activity participation. However, the mechanisms underlying this effect are yet unclear. Using an effort-based decision-making paradigm, we examined whether individuals weigh physical effort-costs more strongly when they are cognitively or physically fatigued. Twenty university students visited the lab on three occasions. On each visit, participants underwent a manipulation that was designed to either induce cognitive fatigue (i.e., 2-back task), physical fatigue (i.e., handgrip exercise), or served as a control condition (i.e., documentary watching). After the manipulations, participants performed an effort-based decision-making task in which they decided for 125 offers whether they accepted the offer to exert the required level of physical effort to obtain rewards that varied in value. The probability to accept offers declined with increasing effort requirements whereas the general probability to accept offers was not reduced by any of the experimental conditions. As expected, the decline in accepted offers with increasing effort requirements was stronger after prolonged exertion of physical effort compared to the control condition. Unexpectedly, this effect was not found after exerting cognitive effort, and exploratory analyses revealed that the impact of physical effort exertion on physical effort-based decisions was stronger than that of cognitive effort exertion. These findings suggest that people weight future physical effort-costs more strongly after exerting physical effort, whereas we could not find any evidence for this after exerting cognitive effort. We discuss multiple explanations for this discrepancy, and outline possibilities for future research.


2020 ◽  
Vol 29 (4) ◽  
pp. 2097-2108
Author(s):  
Robyn L. Croft ◽  
Courtney T. Byrd

Purpose The purpose of this study was to identify levels of self-compassion in adults who do and do not stutter and to determine whether self-compassion predicts the impact of stuttering on quality of life in adults who stutter. Method Participants included 140 adults who do and do not stutter matched for age and gender. All participants completed the Self-Compassion Scale. Adults who stutter also completed the Overall Assessment of the Speaker's Experience of Stuttering. Data were analyzed for self-compassion differences between and within adults who do and do not stutter and to predict self-compassion on quality of life in adults who stutter. Results Adults who do and do not stutter exhibited no significant differences in total self-compassion, regardless of participant gender. A simple linear regression of the total self-compassion score and total Overall Assessment of the Speaker's Experience of Stuttering score showed a significant, negative linear relationship of self-compassion predicting the impact of stuttering on quality of life. Conclusions Data suggest that higher levels of self-kindness, mindfulness, and social connectedness (i.e., self-compassion) are related to reduced negative reactions to stuttering, an increased participation in daily communication situations, and an improved overall quality of life. Future research should replicate current findings and identify moderators of the self-compassion–quality of life relationship.


Author(s):  
Endy Gunanto ◽  
Yenni Kurnia Gusti

In this article we present a conceptual of the effect of cross culture on consumer behavior incorporating the impact of globalization. This conceptual idea shows that culture inûuences various domains of consumer behavior directly as well as through international organization to implement marketing strategy. The conceptual identify several factors such as norm and value in the community, several variables and also depicts the impact of other environmental factors and marketing strategy elements on consumer behavior. We also identify categories of consumer culture orientation resulting from globalization. Highlights of each of the several other articles included in this special issue in Asia region. We conclude with the contributions of the articles in terms of the consumer cultural orientations and identify directions for future research.


2020 ◽  
Vol 91 (8) ◽  
pp. 651-661
Author(s):  
Joshua T. Davis ◽  
Hilary A. Uyhelji

INTRODUCTION: Although the impact of microorganisms on their hosts has been investigated for decades, recent technological advances have permitted high-throughput studies of the collective microbial genomes colonizing a host or habitat, also known as the microbiome. This literature review presents an overview of microbiome research, with an emphasis on topics that have the potential for future applications to aviation safety. In humans, research is beginning to suggest relationships of the microbiome with physical disorders, including type 1 and type 2 diabetes mellitus, cardiovascular disease, and respiratory disease. The microbiome also has been associated with psychological health, including depression, anxiety, and the social complications that arise in autism spectrum disorders. Pharmaceuticals can alter microbiome diversity, and may lead to unintended consequences both short and long-term. As research strengthens understanding of the connections between the microbiota and human health, several potential applications for aerospace medicine and aviation safety emerge. For example, information derived from tests of the microbiota has potential future relevance for medical certification of pilots, accident investigation, and evaluation of fitness for duty in aerospace operations. Moreover, air travel may impact the microbiome of passengers and crew, including potential impacts on the spread of disease nationally and internationally. Construction, maintenance, and cleaning regimens that consider the potential for microbial colonization in airports and cabin environments may promote the health of travelers. Altogether, the mounting knowledge of microbiome effects on health presents several opportunities for future research into how and whether microbiome-based insights could be used to improve aviation safety.Davis JT, Uyhelji HA. Aviation and the microbiome. Aerosp Med Hum Perform. 2020; 91(8):651–661.


Author(s):  
Dzhyhil Yu. ◽  

Residential architecture has one of the most conservative styles based on its specifics. However, today this type of architecture seeks to actively respond to changes in the modern world. These changes are caused by multiple factors, among them are: technological and information progress; lack of resources and environmental pollution; military conflicts and population migration etc. The purpose of this article is to summarize the experience of the Department of Architectural Environment of Lviv Polytechnic National University over housing issues and outline the methodological principles of innovation in designing both individual houses and the architectural environment of residential formations. While writing this article, we analyzed the 15-year experience of Architectural Environment's Department diploma projects. The unique feature of these projects is the priority on the design of the environment. The evolution of diploma project topics is revealed on multiple distinctive examples such as the reconstruction of old buildings in Lviv and the construction of prefabricated homes and container-type housing. Futuristic settlements are represented in projects such as “The Ocean Settlements” and “Prykarpatsk - the City of Future”. Research projects were developed to study current trends in housing design and the impact of innovative technologies on planning decisions. These projects discoursed the protection of housing from traffic noise and issues related to environmental preservation. Innovative architectural ideas of future housing, developed by students in these projects, are based on a combination of aesthetic, technical, and social components of architecture. The conclusion indicates that when educating future architects, it is important to teach them the basics of the craft, as well as the ability to defend their innovative ideas. The emphasis is placed on the importance of educating the architect's personal responsibility for their own design solutions. It is stated that professional motivation and the ability to constantly renew previously acquired knowledge and skills will be among the main tasks in training future architects.


2020 ◽  
Vol 8 (2) ◽  
pp. 112
Author(s):  
Sura Altheeb ◽  
Kholoud Sudqi Al-Louzi

The current research investigates the impact of internal corporate social responsibility on job satisfaction in Jordanian pharmaceutical companies. Quantitative research design and regression analysis were applied on a total of 302 valid returns that were obtained in a questionnaire based survey from 14 pharmaceutical companies among employees, supervisors and managers. The results showed that internal corporate social responsibility was significantly related to job satisfaction and three of its dimensions, namely working conditions, work life balance and empowerment contributed significantly to job satisfaction, whereas employment stability and skills development had no contribution. This study implies that Jordanian pharmaceutical companies have to try their best to promote and facilitate internal corporate social responsibility among their employees in an effort to improve their job satisfaction, which will eventually yield positive results for the company as a whole. In light of these results, the research presented many recommendations for future research; the most important ones were the application of this study in other sectors, cultures, and countries, and using of multi method for collecting data.


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