scholarly journals Controlled Cracking of Large Size Concrete Structures by a Steam Pressure Cracking Agent

2021 ◽  
Vol 10 (1) ◽  
pp. 43-51
Author(s):  
Osamu Kamiya ◽  
Kaito Suzuki ◽  
Etsushi Okuyama ◽  
Naoya Kojima ◽  
Jyunpei Nanao ◽  
...  
Keyword(s):  
Elastic Wave ◽  
Environmental Pollution ◽  
Concrete Structures ◽  
Steam Pressure ◽  
Small Sample ◽  
Micro Particles ◽  
Large Size ◽  
Explosion Method ◽  
The Relationship ◽  
Secondary Contamination

The dismantling of large concrete structures causes environmental pollution due to the dispersion of polluted micro-particles. The purpose of this study is to develop an environmentally friendly demolition method. Steam pressure cracking (SPC) is a method that can safely and quickly separate concrete because there is less vibration compared to the explosion method. To date, the authors have shown that the direction of cracking in a small sample can be controlled by an induction hole. The principle of control is that the elastic wave of compression stress generated from the SPC reaction changes to a tensile elastic wave at the induction hole, and a crack is initiated. In this study, it was shown that the direction of crack propagation can be controlled by using induction holes in large concrete structures that are 1m on each side. Further, in the SPC method, the large amount of concrete powder generated by the explosion method is not produced, and there is no risk of secondary contamination by fine concrete powder. It was also possible to separate small pieces from the end face of the large concrete by SPC and induction holes. The area over which the crack propagated depends on the energy generated from the SPC agent, and the relationship was linear. By applying an SPC agent to dismantling large concrete structures, we can achieve controlled cracking safely and quickly without any environmental pollution. 

Observations on activity, display behavior, coloration and androgen levels in the keeled earless lizard, Holbrookia propinqua

1991 ◽  
Vol 12 (1) ◽  
pp. 57-66 ◽  
Author(s):  
William E. Cooper ◽  
Louis J. Guillette
Keyword(s):  
Body Size ◽  
Small Sample Size ◽  
Small Sample ◽  
Male Body ◽  
Observation Distance ◽  
Large Size ◽  
Color Morphs ◽  
Body Sizes ◽  
Selection For ◽  
The Relationship

AbstractWe observed the distance moved, number of movements, and frequency of displays in ten minute intervals for two male color morphs, coral and yellow, and for brightly colored females, of Holbrookia propinqua. We also measured body sizes and, for males, plasma androgen concentrations. Distance moved, number of movements, and number of social displays were positively correlated in males. Females exhibited similar correlations, but the relationship between distance moved and number of displays was not significant. Males moved more often and greater distances than females. Females performed displays as frequently as did males, perhaps because we selected large, dominant females for observation. Distance moved, number of movements, and number of displays increased with body size in males. That these relationships did not hold in females may indicate a sex difference or reflect the small sample size and body size range of females. Plasma androgen concentrations increased with male body size, suggesting a possible androgenic mechanism of sexual selection for large size. Androgen level did not affect display frequency or distance moved. Distance moved increased with plasma androgen concentration, but when effects of body size were held constant, this relationship vanished. Coral and yellow males did not differ in androgen concentration, size, or in the observed behaviors.

ANALYSIS OF THE INFLUENCE OF DIMENSIONS OF THE ROPE MIDWATER TRAWLS ON THEIR PERFORMANCE SUBJECT TO GEOMETRIC PROPERTIES OF CONE SHELLS

2017 ◽  
pp. 25-33
Author(s):  
Alexander Vasilievich Dvernik
Keyword(s):  
Surface Properties ◽  
Conical Shell ◽  
Side Surface ◽  
Theoretic Analysis ◽  
Good Convergence ◽  
Large Size ◽  
Quality Coefficient ◽  
Geometric Quality ◽  
The Relationship ◽  
Parameters Calculation

The article studies different shell constructions of mid-water trawls and their properties. The problem settled is suggested to be solved taking into account real geometric interrelations between spacious and surface properties of cone shells. The author suggests to accept a so-called geometric quality coefficient as a criterion of the properties of a conical shell, which represents the ratio of the shell to the area of its side surface and by analogy to use it to the shell of the trawl. The relationship between the trawl dimensions and geometric quality coefficient have been studied. Comparing these figures with the actual characteristics of trawls showed good convergence. According to the results of theoretic analysis and parameters calculation, trawl large-size shells will always have advantages in geometric characteristics over mid-size and, especially, small-size shells. The results of the analysis can be used for approximate calculations of the parameters of the trawl and justification of ways to improve the performance of existing mid-water trawls.

scholarly journals AE propagation velocity calculation for stiffness estimation in Pier Luigi Nervi’s concrete structures

2021 ◽  
Vol 8 (1) ◽  
pp. 109-118
Author(s):  
Erica Lenticchia ◽  
Amedeo Manuello Bertetto ◽  
Rosario Ceravolo
Keyword(s):  
Propagation Velocity ◽  
Concrete Structures ◽  
P Wave ◽  
Wave Propagation Velocity ◽  
Damage Level ◽  
Stiffness Characteristics ◽  
Vertical Bearing ◽  
The Relationship ◽  
Ae Signals ◽  
Elastic Characteristics

Abstract In the present paper, the acoustic emission (AE) device is used with an innovative approach, based on the calculation of P-wave propagation velocity (vp ), to detect the stiffness characteristics and the diffused damage of in-service old concrete structures. The paper presents the result of a recent testing campaign carried out on the slant pillars composing the vertical bearing structures designed by Pier Luigi Nervi in one of his most iconic buildings: the Hall B of Torino Esposizioni. In order to investigate the properties of these inclined pillars, localizations of artificial sources (hammer impacts), by the triangulation procedure, were performed on three different inclined elements characterized by stiffness discrepancies due to different causes: the casting procedures, executed in different stages, and the enlargement of the hall happened a few years later the beginning of the construction. In the present work, the relationship between the velocity of AE signals and the elastic characteristics (principally elastic modulus, E) is evaluated in order to discriminate the stiffness level of the slanted pillars. The procedure presented made it possible to develop an innovative investigation method able to estimate, by means of AE, the state of conservation and the elastic properties and the damage level of the monitored concrete and reinforced concrete structures.

scholarly journals Land-Use Change and Health Risks in the Process of Urbanization: A Spatiotemporal Interpretation of a Typical Case in Changzhou, China

Land ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 820
Author(s):  
Dongyang Yang ◽  
Chao Ye ◽  
Jianhua Xu
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Environmental Pollution ◽  
Environmental Health ◽  
Health Risks ◽  
Urban Land ◽  
Urban Land Use ◽  
Urban Land Expansion ◽  
Process Of Urbanization ◽  
The Relationship

China has undergone rapid urban expansion in recent decades. At the same time, environmental pollution and its risk to public health have increased. However, the relationship between urban land-use changes and health is ambiguous and insufficiently understood. Based on a typical city-scale case—namely, Changzhou, China—this research aimed to interpret the evolution of health risks alongside land-use change during the process of urbanization. We gathered data from multiple sources, including population mortality data, socioeconomic data, remote-sensing images, data for the points of interest of enterprises, and relevant information on environmental health events and cancers. The results showed that Changzhou’s urbanization was typical insofar as it was characterized by massive growth in industry, a rapid increase in the urban population, and urban land expansion. Health risks related to environmental pollution increased considerably with urban land expansion over time, and they increased with proximity to the pollution. The results from a generalized linear model confirmed that Changzhou’s urbanization triggered increasing health risks. Our study interpreted the relationship between urban land expansion and health risks from a spatiotemporal perspective. It can be used as a reference for urban planning and policymaking with regard to urban environmental health.

When do job insecure employees adapt to change?

2019 ◽  
Vol 25 (3) ◽  
pp. 271-286 ◽  
Author(s):  
Kristi N. Lavigne ◽  
Victoria L. Whitaker ◽  
Dustin K. Jundt ◽  
Mindy K. Shoss
Keyword(s):  
Job Insecurity ◽  
Small Sample ◽  
Adaptive Performance ◽  
Work Behaviors ◽  
Content Type ◽  
Work Tasks ◽  
Main Effect ◽  
Low Levels ◽  
The Impact ◽  
The Relationship

Purpose The purpose of this paper is to examine the relationship between job insecurity and adaptive performance (AP), contingent on changes to core work tasks, which we position as a situational cue to employees regarding important work behaviors. Design/methodology/approach Employees and their supervisors were invited to participate in the study. Supervisors were asked to provide ratings of employees’ AP and changes to core tasks; employees reported on job insecurity. Findings As predicted, changes to core tasks moderated the relationship between job insecurity and AP. Job insecurity was negatively related to AP for those experiencing low levels of change, but was not related to AP for those experiencing high levels of change. Counter to expectations, no main effect of job insecurity was found. Research limitations/implications This study employed a fairly small sample of workers from two organizations, which could limit generalizability. Practical implications The study identifies changes to core tasks as a boundary condition for the job insecurity–AP relationship. Findings suggest that organizations may not observe deleterious consequences of job insecurity on AP when changes to core tasks are high. Originality/value Few researchers have examined boundary conditions of the impact of job insecurity on AP. Furthermore, inconsistent findings regarding the link between job insecurity and AP have emerged. This study fills the gap and expands upon previous research by examining changes to core tasks as a condition under which job insecurity does not pose an issue for AP.

Improving new product development performance by risk management

2016 ◽  
Vol 31 (3) ◽  
pp. 418-425 ◽  
Author(s):  
Mehran Salavati ◽  
Milad Tuyserkani ◽  
Seyyede Anahita Mousavi ◽  
Nafiseh Falahi ◽  
Farshid Abdi
Keyword(s):  
Risk Management ◽  
Product Development ◽  
New Product Development ◽  
Small Sample Size ◽  
New Product ◽  
Small Sample ◽  
Content Type ◽  
Total Performance ◽  
The Relationship ◽  
Npd Performance

Purpose The principal aim of this study is to investigate the relationship between technological, marketing, organizational and commercialization risk management on new product development (NPD) performance. Design/methodology/approach Based on questionnaire, the data were collected from a sample of general automotive industry in Iran. Based on theoretical considerations, a model was proposed and descriptive statistic and hierarchical regression were used to measure the relationship between risk management factors and NPD performance. Findings Data analysis revealed that if organization can amplify their knowledge and information about risk and main factors that affect NPD process, not only can they do their work better but can also increase their ability to predict future happenings that affect performance. Research limitations/implications First, due to the relatively small sample size, caution should be exercised when interpreting the results. Second, the data were collected from automotive producer in Iran, which may restrict to some extent generalizability of the findings. Practical implications The results suggest that managers should consider more attention to risk management. If managers spread the risk management in all aspects of the NPD project, total performance will be increased and it can develop the probability of NPD success. Also organizations should perform great market research due to best commercialization. Originality/value Past researches have presented complete information about NPD process. But identifying and considering the effect of the risk management parameters that are connected to the NPD process were the main thrusts to perform the study. In this paper, based on past research about risk management of NPD, the extra aspect of process that can improve total performance of NPD has been examined.

Overconfidence of vocational education students when entering higher education

2015 ◽  
Vol 57 (4) ◽  
pp. 429-447 ◽  
Author(s):  
Mark P. Bowden ◽  
Subhash Abhayawansa ◽  
John Bahtsevanoglou
Keyword(s):  
Higher Education ◽  
Self Efficacy ◽  
Further Education ◽  
Small Sample ◽  
First Year ◽  
Education Students ◽  
Content Type ◽  
The Relationship ◽  
Practical Implications

Purpose – There is evidence that students who attend Technical and Further Education (TAFE) prior to entering higher education underperform in their first year of study. The purpose of this paper is to examine the role of self-efficacy in understanding the performance of students who completed TAFE in the previous year in a first year subject of microeconomics in a dual sector university in Melbourne, Australia. Design/methodology/approach – The study utilises data collected by surveys of 151 students. Findings – A student’s self-efficacy is positively associated with their marks in a first year subject of microeconomics. However, the relationship between final marks and self-efficacy is negative for those students who attended TAFE in the previous year suggesting that they suffer from the problem of overconfidence. When holding self-efficacy constant, using econometric techniques, TAFE attendance is found to be positively related to final marks. Research limitations/implications – The findings are exploratory (based on a small sample) and lead to a need to conduct cross institutional studies. Practical implications – The research points to the need for early interventions so that TAFE students perform well in their first year of higher education. It also points to potential issues in the development of Victorian Certificate of Applied Learning (VCAL) programs. Originality/value – To the best of the authors’ knowledge, this is the first paper to examine the inter-related impact of attendance at TAFE in the previous year and self-efficacy on the subsequent academic performance of TAFE students.

scholarly journals Titan Cells Confer Protection from Phagocytosis in Cryptococcus neoformans Infections

2012 ◽  
Vol 11 (6) ◽  
pp. 820-826 ◽  
Author(s):  
Laura H. Okagaki ◽  
Kirsten Nielsen
Keyword(s):  
Cryptococcus Neoformans ◽  
Critical Role ◽  
Cell Formation ◽  
Pulmonary Cryptococcosis ◽  
Content Type ◽  
Cell Production ◽  
Human Fungal Pathogen ◽  
Large Size ◽  
Large Particles ◽  
The Relationship

ABSTRACTThe human fungal pathogenCryptococcus neoformansproduces an enlarged “titan” cell morphology when exposed to the host pulmonary environment. Titan cells exhibit traits that promote survival in the host. Previous studies showed that titan cells are not phagocytosed and that increased titan cell production in the lungs results in reduced phagocytosis of cryptococcal cells by host immune cells. Here, the effect of titan cell production on host-pathogen interactions during early stages of pulmonary cryptococcosis was explored. The relationship between titan cell production and phagocytosis was found to be nonlinear; moderate increases in titan cell production resulted in profound decreases in phagocytosis, with significant differences occurring within the first 24 h of the infection. Not only were titan cells themselves protected from phagocytosis, but titan cell formation also conferred protection from phagocytosis to normal-size cryptococcal cells. Large particles introduced into the lungs were not phagocytosed, suggesting the large size of titan cells protects against phagocytosis. The presence of large particles was unable to protect smaller particles from phagocytosis, revealing that titan cell size alone is not sufficient to provide the observed cross-protection of normal-size cryptococcal cells. These data suggest that titan cells play a critical role in establishment of the pulmonary infection by promoting the survival of the entire population of cryptococcal cells.

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