scholarly journals A Review on the Performance Evaluation of Autonomous Self-Healing Bacterial Concrete: Mechanisms, Strength, Durability, and Microstructural Properties

2022 ◽  
Vol 6 (1) ◽  
pp. 23
Author(s):  
Salmabanu Luhar ◽  
Ismail Luhar ◽  
Faiz Uddin Ahmed Shaikh

The development of cracks, owing to a relatively lower tensile strength of concrete, diverse loading, and environmental factors driving the deterioration of structures, is an inescapable key concern for engineers. Reparation and maintenance operations are thus extremely important to prevent cracks from spreading and mitigating the lifetime of structures. However, ease of access to the cracked zone may be challenging, and it also needs funds and manual power. Hence, autonomous sealing of cracks employing microorganisms into the concrete sans manual intervention is a promising solution to the dilemma of the sustainable improvement of concrete. ‘Ureolytic bacteria’, key organism species in rumen-producing ‘urease’ enzymes such as Bacillus pasteurii or subtilis—when induced—are capable of producing calcium carbonate precipitations into the concrete. As their cell wall is anionic, CaCO3 accumulation on their surface is extensive, and the whole cell, therefore, becomes crystalline and ultimately plugs pores and cracks. This natural induction technique is an environmentally friendly method that researchers are studying intensively. This manuscript reviews the application process of bacterial healing to manufacture autonomous self-healing bacterial concrete. Additionally, it provides a brief review of diverse attributes of this novel concrete which demonstrate the variations with the auto-addition of different bacteria, along with an evaluation of crack healing as a result of the addition of these bacteria directly into concrete or after encapsulation in a protective shell. Comparative assessment techniques for autonomous, bio-based self-healing are also discussed, accompanied by progress, potential, modes of application of this technique, and its resultant benefits in the context of strength and durability. Imperatives for quantitative sustainability assessment and industrial adoption are identified, along with the sealing of artificially cracked cement mortar with sand as a filling material in given spaces, as well as urea and CaCl2 medium treatment with Bacillus pasteurii and Sporosarcina bacteria. The assessment of the impact on the compressive strength and rigidity of cement mortar cubes after the addition of bacteria into the mix is also considered. Scanning electron microscope (SEM) images on the function of bacteria in mineral precipitation that is microbiologically induced are also reviewed. Lastly, future research scope and present gaps are recognised and discussed.

Author(s):  
Dhiraj Ahiwale ◽  
Rushikesh Khartode

This study examines the impact of bacterial concrete on strength and self-healing. Bacterial concrete has better compressive strength, permeability, corrosion resistance, chemical precursors, alkalinity resistance, and mechanical stress. Bacillus subtilis calcium lactate and spore powder effects are explored in this study, and the influence of this bacterial form on strength and self-healing capacity to crack repair. The Bacillus subtilis concentration 105 cells/mL is used in concrete with calcium lactate 0.3% of cement. In another trial, calcium lactates 0.3% and spore powder 0.5% of cement with Bacillus subtilis concentration of 105 cells/mL and lightweight expandable clay aggregate (LECA) is 30% replaced to the coarse aggregate used in concrete respectively. The conventional concrete and bacterial concrete cubes were molded with dimensions of 150 mm x 150 mm x 150 mm, cylinders with dimensions of 100 mm x 200 mm, and a beam with dimensions of 100 mm x 100 mm x 500 mm. These specimens were evaluated after 7 and 28 days of cure. The compressive, split tensile, and flexural strength of bacterial concrete was raised by 23%, 8%, and 7%, respectively when compared to conventional concrete. Thus, the experimental findings reveal that Bacillus subtilis at 105 cells/ml cells with 0.3% calcium lactate has a substantial impact on the strength and self-healing of bacterial concrete.


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.


2013 ◽  
Vol 1 (3) ◽  
pp. 9
Author(s):  
Jennifer Lee Brady ◽  
Annie Hoang ◽  
Olivia Siswanto ◽  
Jordana Riesel ◽  
Jacqui Gingras

Obtaining dietetic licensure in Ontario requires completion of a Dietitians of Canada (DC) accredited four-year undergraduate degree in nutrition and an accredited post-graduate internship or combined Master’s degree program. Given the scarcity of internship positions in Ontario, each year approximately two-thirds of the eligible applicants who apply do not receive a position XX, XX, XX, XX, XX, XX, in press). Anecdotally, not securing an internship position is known to be a particularly disconcerting experience that has significant consequences for individuals’ personal, financial, and professional well-being. However, no known empirical research has yet explored students’ experiences of being unsuccessful in applying for internship positions. Fifteen individuals who applied between 2005 and 2009 to an Ontario-based dietetic internship program, but were unsuccessful at least once, participated in a one-on-one semi-structured interview. Findings reveal that participants’ experiences unfold successively in four phases that are characterized by increasingly heightened emotional peril: naïveté, competition, devastation, and frustration. The authors conclude that the current model of dietetic education and training in Ontario causes lasting distress to students and hinders the future growth and vitality of the dietetic profession. Further research is required to understand the impact of the current model on dietetic educators, internship coordinators, and preceptors as coincident participants in the internship application process.


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.


2020 ◽  
Author(s):  
Martina Bientzle ◽  
Marie Eggeling ◽  
Simone Korger ◽  
Joachim Kimmerle

BACKGROUND: Successful shared decision making (SDM) in clinical practice requires that future clinicians learn to appreciate the value of patient participation as early as in their medical training. Narratives, such as patient testimonials, have been successfully used to support patients’ decision-making process. Previous research suggests that narratives may also be used for increasing clinicians’ empathy and responsiveness in medical consultations. However, so far, no studies have investigated the benefits of narratives for conveying the relevance of SDM to medical students.METHODS: In this randomized controlled experiment, N = 167 medical students were put into a scenario where they prepared for medical consultation with a patient having Parkinson disease. After receiving general information, participants read either a narrative patient testimonial or a fact-based information text. We measured their perceptions of SDM, their control preferences (i.e., their priorities as to who should make the decision), and the time they intended to spend for the consultation.RESULTS: Participants in the narrative patient testimonial condition referred more strongly to the patient as the one who should make decisions than participants who read the information text. Participants who read the patient narrative also considered SDM in situations with more than one treatment option to be more important than participants in the information text condition. There were no group differences regarding their control preferences. Participants who read the patient testimonial indicated that they would schedule more time for the consultation.CONCLUSIONS: These findings show that narratives can potentially be useful for imparting the relevance of SDM and patient-centered values to medical students. We discuss possible causes of this effect and implications for training and future research.


2009 ◽  
Vol 8 (2) ◽  
pp. 89-94
Author(s):  
Robyn J. Barst ◽  
Marc Humbert ◽  
Ivan M. Robbins ◽  
Lewis J. Rubin ◽  
Robyn J. Park

A discussion among attendees of the 4th World Symposium on Pulmonary Hypertension took place to share “an insider's look” into the current and future research and treatment implications in pulmonary hypertension. Myung H. Park, MD, guest editor of this issue of Advances in Pulmonary Hypertension, Assistant Professor of Medicine and Director, Pulmonary Vascular Diseases Program, Division of Cardiology, University of Maryland School of Medicine, Baltimore, moderated the discussion. Participants included Robyn Barst, MD, Professor Emerita, Columbia University, New York; Marc Humbert, MD, PhD, Universite Paris-Sud, French Referal Center for Pulmonary Hypertension, Hopital Antoine-Beclere, Assistance Publique Hopitaux de Paris, Clamart, France; Ivan Robbins, MD, Associate Professor of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee; and Lewis J. Rubin, MD, Clinical Professor, Department of Medicine, University of California, San Diego.


2018 ◽  
Vol 32 (2) ◽  
pp. 103-119
Author(s):  
Colleen M. Boland ◽  
Chris E. Hogan ◽  
Marilyn F. Johnson

SYNOPSIS Mandatory existence disclosure rules require an organization to disclose a policy's existence, but not its content. We examine policy adoption frequencies in the year immediately after the IRS required mandatory existence disclosure by nonprofits of various governance policies. We also examine adoption frequencies in the year of the subsequent change from mandatory existence disclosure to a disclose-and-explain regime that required supplemental disclosures about the content and implementation of conflict of interest policies. Our results suggest that in areas where there is unclear regulatory authority, mandatory existence disclosure is an effective and low cost regulatory device for encouraging the adoption of policies desired by regulators, provided those policies are cost-effective for regulated firms to implement. In addition, we find that disclose-and-explain regulatory regimes provide stronger incentives for policy adoption than do mandatory existence disclosure regimes and also discourage “check the box” behavior. Future research should examine the impact of mandatory existence disclosure rules in the year that the regulation is implemented. Data Availability: Data are available from sources cited in the text.


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