Lateral Extent and Environmental Effects of Dynamic Compaction in a Coastal Area of Southern Iran

2019 ◽  
Vol 25 (3) ◽  
pp. 203-211
Author(s):  
Akbar Cheshomi

ABSTRACT The lateral extent, depth of densification, and environmental effects of dynamic compaction (DC) were investigated for a very loose to loose silty sand layer with thickness varying from 6 to 12 m in a coastal area in southern Iran. Cone penetration testing (CPT) was done at different distances from the center of the point of impact before and after DC. The increase in cone resistance at different distances is plotted versus dimensionless distance X/D (X = distance from center point of impact and D = diameter of tamper), and equations are proposed to describe them. The amount of soil densification decreased progressively until the distance from the center of the tamper increased to about 3.3 times the diameter of the tamper, beyond which there was no densification. The peak partial velocity (PPV) measured at different distances from the center point of impact was used to determine the environmental effect caused by the impact of the tamper. Equations describing the relationship between the weight of the tamper, tamper drop height, distance from the center point of impact, and PPV for this site are proposed.

Author(s):  
Jing-Wen Chen ◽  
Fu-Cheng Chen

Dynamic compaction is currently regarded as one of the quick but cost-effective method for soil densification to resist the potential of soil liquefaction during earthquake. Most practices and studies reveal the depth of densification is mainly limited by the compaction energy without considering the effect of water table. In this experimental study, the impact performances under both presence and absence of water level without changing the compaction energy were presented. The Single-point Impact Test is developed to perform a series of tests on soils under different water levels and drained conditions. Meanwhile, an automatic cone penetrometer is also developed to evaluate the effectiveness. The boundary effect of soil container used in the test is also discussed. The impact-induced pore pressures and dissipation periods are measured and compared with a field measurement. The relationship between the effective dynamic stresses and corresponding cone resistances in soils is highlighted. The performance of dynamic impacts is evaluated by a term of improvement ratio.


2013 ◽  
Vol 13 (2) ◽  
Author(s):  
Wisyanto Wisyanto

Tsunami which was generated by the 2004 Aceh eartquake has beenhaunting our life. The building damage due to the tsunami could be seenthroughout Meulaboh Coastal Area. Appearing of the physical loss wasclose to our fault. It was caused by the use dan plan of the land withoutconsidering a tsunami disaster threat. Learning from that event, we haveconducted a research on the pattern of damage that caused by the 2004tsunami. Based on the analysis of tsunami hazard intensity and thepattern of building damage, it has been made a landuse planning whichbased on tsunami mitigation for Meulaboh. Tsunami mitigation-based ofMeulaboh landuse planning was made by intergrating some aspects, suchas tsunami protection using pandanus greenbelt, embankment along withhigh plants and also arranging the direction of roads and setting of building forming a rhombus-shaped. The rhombus-shaped of setting of the road and building would reduce the impact of tsunamic wave. It is expected that these all comprehensive landuse planning will minimize potential losses in the future .


2021 ◽  
Vol 7 (7) ◽  
pp. 565
Author(s):  
Anindita Lahiri ◽  
Brian R. Murphy ◽  
Trevor R. Hodkinson

Fraxinus excelsior populations are in decline due to the ash dieback disease Hymenoscyphus fraxineus. It is important to understand genotypic and environmental effects on its fungal microbiome to develop disease management strategies. To do this, we used culture dependent and culture independent approaches to characterize endophyte material from contrasting ash provenances, environments, and tissues (leaves, roots, seeds). Endophytes were isolated and identified using nrITS, LSU, or tef DNA loci in the culture dependent assessments, which were mostly Ascomycota and assigned to 37 families. Few taxa were shared between roots and leaves. The culture independent approach used high throughput sequencing (HTS) of nrITS amplicons directly from plant DNA and detected 35 families. Large differences were found in OTU diversity and community composition estimated by the contrasting approaches and these data need to be combined for estimations of the core endophyte communities. Species richness and Shannon index values were highest for the leaf material and the French population. Few species were shared between seed and leaf tissue. PCoA and NMDS of the HTS data showed that seed and leaf microbiome communities were highly distinct and that there was a strong influence of Fraxinus species identity on their fungal community composition. The results will facilitate a better understanding of ash fungal ecology and are a step toward identifying microbial biocontrol systems to minimize the impact of the disease.


Kybernetes ◽  
2020 ◽  
Vol 49 (11) ◽  
pp. 2713-2735 ◽  
Author(s):  
Xiaomin Fan ◽  
Yingzhi Xu ◽  
Yongqing Nan ◽  
Baoli Li ◽  
Haiya Cai

Purpose The purpose of this paper is to analyse the impact of high-speed railway (HSR) on industrial pollution emissions using the data for 285 prefecture-level cities in China from 2004 to 2016. Design/methodology/approach The research method used in this paper is the multi-period difference-in-differences (DID) model, which is an effective policy effect assessment method. To further address the issue of endogeneity, the DID integrated with the propensity score matching (PSM-DID) approach is employed to eliminate the potential self-selection bias. Findings The results show that the HSR has significantly reduced industrial pollution emissions, which is validated by several robustness tests. Compared with peripheral cities, HSR exerts a greater impact on industrial pollution emissions in central cities. In addition, the mechanism test reveals that the optimised allocation of inter-city industries is an important channel for HSR to mitigate industrial pollution emissions, and this is closely related to the location of HSR stations. Originality/value Previous studies have paid more attention to evaluating the economic effects of HSR, however, most of these studies overlook its environmental effects. Consequently, the impact of HSR on industrial pollution emissions is led by using multi-period DID models in this paper, in which the environmental effects are measured. The results of this paper can provide a reference for the pollution reduction policies and also the coordinated development of economic growth and environmental quality.


2015 ◽  
Vol 105 (5) ◽  
pp. 621-628 ◽  
Author(s):  
C.P. Bonsignore ◽  
F. Manti ◽  
E. Castiglione

AbstractParasitoids are significant enemies of many economically important insects and there is some evidence to suggest that their actions have a role in terminating the outbreaks of forest Lepidoptera populations. In this study, we examined the impact of parasitoids on the pupae of the pine processionary moth, and highlighted the presence of several parasitoid species for this developmental stage. A higher rate of parasitism was found when the pupal density in the soil was reduced, but the rate of parasitism was not influenced by pupal morphological traits or by the presence or absence of a cocoon around a pupa. Of the external factors examined, a delay in the time of descent of larvae from the trees had a positive effect on the level of parasitism. Observational data indicated that dipteran and hymenopteran were the most abundant parasitoids to emerge from moth pupae. Our study highlights the complexity of the parasitoid–host dynamics, and stresses the importance of carefully determining environmental effects on host–parasitoid relations.


2007 ◽  
Vol 09 (02) ◽  
pp. 141-160 ◽  
Author(s):  
JENNIFER FRANZ ◽  
COLIN KIRKPATRICK

Since the adoption of the EU's first Sustainable Development Strategy in 2001, the European Commission has been committed to undertaking impact assessments of its major policy proposals, covering the potential positive and negative economic, social and environmental effects both inside and outside the European Union. This paper provides as evaluation of a sample of the Commission's recent EC Impact Assessments, focusing on the extent to which the goal of sustainable development has been integrated into the impact assessment analysis.


2011 ◽  
Vol 4 ◽  
pp. ASWR.S6551
Author(s):  
Khandakar Habib Al Razi ◽  
Moritomi Hiroshi ◽  
Kambara Shinji

In Japan, mercury and its compounds were categorized as hazardous air pollutants in 1996 and are on the list of “Substances Requiring Priority Action” published by the Central Environmental Council of Japan. The Air Quality Management Division of the Environmental Bureau, Ministry of the Environment, Japan, selected the current annual mean environmental air quality standard for mercury and its compounds of 0.04 μg/m3. Long-term exposure to mercury and its compounds can have a carcinogenic effect, inducing eg, Minamata disease. This study evaluates the impact of mercury emissions on air quality in the coastal area of the Sea of Japan. Average yearly emission of mercury from an elevated point source in this area with background concentration and one-year meteorological data were used to predict the ground level concentration of mercury. The annual mean concentration distribution of mercury and its compounds were calculated for the middle part of Honshu Island, which served as a background level of mercury concentration for the coastal are of the Sea of Japan. To estimate the concentration of mercury and its compounds in air of the local area, two different simulation models have been used. The first is the National Institute of Advanced Science and Technology Atmospheric Dispersion Model for Exposure and Risk Assessment (AIST-ADMER) that estimates regional atmospheric concentration and distribution. The second is the Ministry of Economy, Trade and Industry Low Rise Industrial Source Dispersion Model (METI-LIS) that estimates the atmospheric concentration distribution in the vicinity of facilities.


Toxics ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 49 ◽  
Author(s):  
Nozomi Tatsuta ◽  
Kunihiko Nakai ◽  
Mineshi Sakamoto ◽  
Katsuyuki Murata ◽  
Hiroshi Satoh

Seafood is an important component in a healthy diet and may contain methylmercury or other contaminants. It is important to recognize the risks and benefits of consuming seafood. A longitudinal prospective birth cohort study has been conducted to clarify the effects of neurotoxicants on child development—the Tohoku Study of Child Development (TSCD) in Japan. TSCD comprises two cohorts; a polychlorinated biphenyls (PCB) cohort (urban area) and a methylmercury cohort (coastal area). Our previous results from the coastal area showed prenatal methylmercury exposure affected psychomotor development in 18-month-olds, and boys appear to be more vulnerable to the exposure than girls. In this report, we have added the urban area cohort and we reanalyzed the impact of prenatal exposure to methylmercury, which gave the same results as before. These findings suggest prenatal exposure to low levels methylmercury may have adverse effects on child development, especially in boys.


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