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71.
Due to the increasingly serious environmental problems presented by waste tires, the feasibility of using elastic and flexible tire-rubber particles as aggregate in concrete is investigated in this study. Tire-rubber particles composed of tire chips, crumb rubber, and a combination of tire chips and crumb rubber, were used to replace mineral aggregates in concrete. These particles were used to replace 12.5%, 25%, 37.5%, and 50% of the total mineral aggregate's volume in concrete. Cylindrical shape concrete specimens 15 cm in diameter and 30 cm in height were fabricated and cured. The fresh rubberized concrete exhibited lower unit weight and acceptable workability compared to plain concrete. The results of a uniaxial compressive strain control test conducted on hardened concrete specimens indicate large reductions in the strength and tangential modulus of elasticity. A significant decrease in the brittle behavior of concrete with increasing rubber content is also demonstrated using nonlinearity indices. The maximum toughness index, indicating the post failure strength of concrete, occurs in concretes with 25% rubber content. Unlike plain concrete, the failure state in rubberized concrete occurs gently and uniformly, and does not cause any separation in the specimen. Crack width and its propagation velocity in rubberized concrete are lower than those of plain concrete. Ultrasonic analysis reveals large reductions in the ultrasonic modulus and high sound absorption for tire-rubber concrete. 相似文献
72.
Aishah S. A. K. Sharifah Hanafiah Zainal Abidin Mohamad R. Sulaiman Kheng H. Khoo Hairi Ali 《Journal of Material Cycles and Waste Management》2008,10(2):116-123
Malaysia is in dire need of alternatives to landfilling for solid waste management. Recently, landfills have faced the problems
of overfilling, overflowing of leachates leading to pollution of water resources, and uncontrolled dust emissions adversely
affecting the local environment. With the rising cost of urbanization coupled with the high rate of waste generation, one
possible method of waste treatment that is receiving particular attention by the government is incineration. Incineration
of solid waste is rather new in Malaysia, with limited usage in handling small sources of waste generation such as the municipal
solid waste (MSW) of resort islands; however, its potential in ameliorating the problems associated with solid waste treatment
may make it an attractive alternative to landfill. This article presents the results of test runs conducted to investigate
the performance of a locally designed and manufactured rotary kiln incinerator (RKI). The test runs were conducted using MSW
collected from the Shah Alam municipality. The combustion efficiency was analyzed by looking at the temperature profiles and
chemical species concentrations. To complement the combustion characteristics measurements, predictions of the air flow in
the incinerator during the process were also investigated. The overall performance of the RKI suggests that it is suitable
for treating MSW. 相似文献
73.
Nevzat Damla Ugur Cevik Ali Ihsan Kobya Berna Ataksor Umit Isık 《Environmental monitoring and assessment》2010,160(1-4):401-412
The province of Batman, located in southern Anatolia, has a population of approximately 500,000. To our knowledge, there exists no information regarding the environmental radioactivity in this province. Therefore, gamma activity measurements in soil, building materials and water samples and an indoor radon survey have been carried out in the Batman province. The mean activity concentrations of the natural radionuclides (226Ra, 232Th and 40K) and a fission product (137Cs) were 35 ± 8, 25 ± 10, 274 ± 167 and 12 ± 7 Bq kg???1, respectively, in the soil samples. The concentrations of 226Ra, 232Th and 40K in the selected building materials ranged from 18 to 48 Bq kg???1, 8 to 49 Bq kg???1 and 68 to 477 Bq kg???1, respectively. All the calculated radium equivalent (Raeq) activity values of the building material samples are lower than the limit of 370 Bq kg???1, equivalent to a γ-dose of 1.5 mSv year???1. The activity concentrations of 226Ra, 232Th and 40K in tap waters collected from the study area were determined with mean specific activity concentrations of 42 ± 15, 35 ± 9 and 524 ± 190 mBq L???1, respectively. Indoor radon measurements were made at 95 dwellings in Batman using a CR-39 detector. The radon concentration levels were found to vary from 23 to 145 Bq m???3. The arithmetic mean of the measured radon concentration levels was found to be 84 Bq m???3 with a standard deviation value of 23 Bq m???3. The measurement results obtained in this study did not significantly differ from those taken in other parts of the country. The data generated in this study can be used to determine whether the Batman province is in a normal or high background radiation area and provides a valuable database for future estimations of the impact of radioactive pollution. 相似文献
74.
Selehattin Yılmaz Melike Türe Murat Sadıkoglu Ali Duran 《Environmental monitoring and assessment》2010,167(1-4):235-242
The wastewater pollution in industrial areas is one of the most important environmental problems. Heavy metal pollution, especially chromium pollution in the wastewater sources from electroplating, dyeing, and tannery, has affected the life on earth. This pollution can affect on all ecosystems and human health directly or by food chain. Therefore, the determination of total chromium in this study is of great importance. In this study, accurate, rapid, sensitive, selective, simple, and low-cost technique for the direct determination of total Cr in wastewater samples collected from the some Cr electroplating factories in March 2008 by inductively coupled plasma-atomic emission spectrometry has been developed. The analysis of a given sample is completed in about 15 min by this technique applied. As the result of the chromium analysis, the limit of quantification for the total Cr were founded to be over the limit value (0.05 mg L???1; WHO, EPA, TSE 266, and inland water quality classification) as 1,898.78 ± 0.34 mg/L at station 1 and 3,189.02 ± 0.56 mg/L at station 2. The found concentration of total Cr has been determined to be IV class quality water according to the inland water classification. In order to validate the applied method, recovery studies were performed. 相似文献
75.
This article reports the results of a study that explored whether outdoor recreational areas are sufficient in Istanbul in terms of their surface area and facility characteristics. All the municipalities in 32 subprovinces of Istanbul were sent a survey in 2007 and asked to prepare a list of their outdoor recreational areas including their names, addresses, size, and facilities. All the data collected from the municipalities were used to create a GIS-based inventory by using GIS and remote sensing. As the study revealed, the outdoor recreational areas in Istanbul are far behind meeting the recreational needs of the residents in terms of area per person and facility characteristics. There are 2,470 areas which were dedicated to outdoor recreational activities in Istanbul. Total surface area of all these outdoor recreational areas is 19,2 sq kilometers; this means 1.52 m2 recreational area per person in the city. This value is very low when compared to that of many cities in Europe and USA. As the study also revealed, the majority of outdoor recreational areas in Istanbul are poor in facility. Majority of the existing outdoor recreational areas are small and do not provide the public with many opportunities to engage in different outdoor activities. A more sustainable and efficient recreational plan is needed in Istanbul to meet the various recreational needs of its residents. 相似文献
76.
Nevzat Damla Uğur Cevik Ali Ihsan Kobya Ahmet Celik Necati Celik 《Environmental monitoring and assessment》2010,170(1-4):457-466
The activity concentrations of 226Ra, 232Th, and 40K in lime and gypsum samples used as building materials in Turkey were measured using gamma spectrometry. The mean activity concentrations of 226Ra, 232Th, and 40K were found to be 38 ± 16, 20 ± 9, and 156 ± 54 Bq kg???1 for lime and found to be 17 ± 6, 13 ± 5, and 429 ± 24 Bq kg???1 for gypsum, respectively. The radiological hazards due to the natural radioactivity in the samples were inferred from calculations of radium equivalent activities (Raeq), indoor absorbed dose rate in the air, the annual effective dose, and gamma and alpha indices. These radiological parameters were evaluated and compared with the internationally recommended limits. The experimental mass attenuation coefficients (μ/ρ) of the samples were determined in the energy range 81–1,332 keV. The experimental mass attenuation coefficients were compared with theoretical values obtained using XCOM. It is found that the calculated values and the experimental results are in good agreement. 相似文献
77.
Ali Naderi Beni Michael Kühn Robert Meyer Christoph Clauser 《Environmental Modeling and Assessment》2012,17(4):337-351
We study opportunities for CO2 sequestration in geological formations of the state North Rhine Westphalia in Germany. Simulations are performed for evaluating a potential site within the Bunter sandstone formation near the town of Minden in a depth?of around 3,000 m using the numerical simulator TOUGHREACT. Our focus is on three CO2 storage mechanisms: (1) hydrodynamic trapping, (2) dissolution trapping, and (3) mineral trapping. The results show that due to buoyancy the injected CO2 phase initially migrates towards the top of the reservoir and is hydrodynamically trapped beneath the confining layer of the cap rock. Then, the CO2 spreads laterally and dissolves partially in the formation water. The dissolution of CO2 results in an increase of the density of the brine causing a downward migration until it settles after 10,000 years at the bottom of the reservoir. The simulations indicate that after 10,000 years, 15% (17 Mt) from a total of 114 Mt injected CO2 are trapped hydrodynamically, 20% (23 Mt) are trapped by dissolution, and 65% (74 Mt) are fixed in newly formed carbonates such as dawsonite, ankerite, and siderite. Within our study pressure increases near the injection well by a factor of 1.1 which is lower than the upper limit usually accepted in gas storage operations. The mineral reactions cause a net decrease of porosity and in turn a decrease of permeability down to 9% of the initial value in parts of the reservoir. 相似文献
78.
Heavy metal contamination from mining sites in South Morocco: Monitoring metal content and toxicity of soil runoff and groundwater 总被引:5,自引:0,他引:5
El Khalil H El Hamiani O Bitton G Ouazzani N Boularbah A 《Environmental monitoring and assessment》2008,136(1-3):147-160
The aim of the present work is the assessment of metal toxicity in runoff, in their contaminated soils and in the groundwater
sampled from two mining areas in the region of Marrakech using a microbial bioassay MetPLATE™. This bioassay is based on the
specific inhibition of the β-galactosidase enzyme of a mutant strain of Escherichia coli, by the metallic pollutants. The stream waters from all sampling stations in the two mines were all very toxic and displayed
percent enzyme inhibition exceeding 87% except SWA4 and SWB1 stations in mine C. Their high concentrations of copper (Cu) and zinc (Zn) confirm the acute toxicity shown by MetPLATE.
The pH of stream waters from mine B and C varied between 2.1 and 6.2 and was probably responsible for metal mobilization,
suggesting a problem of acid mine drainage in these mining areas. The bioassay MetPLATE™ was also applied to mine tailings
and to soils contaminated by the acidic waters. The results show that the high toxicity of these soils and tailings was mainly
due to the relatively concentration of soluble Zn and Cu. The use of MetPLATE™ in groundwater toxicity testing shows that,
most of the samples exhibited low metal toxicity (2.7–45.5% inhibition) except GW3 of the mine B (95.3% inhibition during
the wet season and 82.9% inhibition during the dry season). This high toxicity is attributed to the higher than usual concentrations
of Cu (189 μg Cu l−1) and Zn (1505 μg Zn l−1). These results show the potential risk of the contamination of different ecosystems situated to the vicinity of these two
metalliferous sites. The general trend observed was an increase in metal toxicity measured by the MetPLATE with increasing
total and mobile metal concentrations in the studied matrices. Therefore, the MetPLATE bioassay is a reliable and fast bioassay
to estimate the metals toxicity in the aquatic and solids samples. 相似文献
79.
A framework for dissolved oxygen (DO) modeling of the Ravi River has been developed based on a combination of laboratory measurements
and field and monitoring data. Both the classical Streeter-Phelps (CSP) and the modified Streeter-Phelps (MSP) models are
used for DO simulations. The MSP model considers the carbonaceous biochemical oxygen demand (CBOD) and nitrogenous biochemical
oxygen demand (NBOD) separately, whereas the CSP model is evaluated considering only the CBOD and NBOD is incorporated in
the overall BOD utilization rate. CBOD, NBOD and BOD rates have been determined through long-term BOD analysis of five main
wastewater outfalls and two surface drains discharging into the Ravi River over a 98 km stretch. Analysis by Thomas Method
manifests strong coefficient of determination “R2” between 0.72 and 0.98 for all the three types of BOD rates. Sensitivity analyses have also been carried out to find out
a suitable reaeration rate formula for highly variable flows in the Ravi River. The CSP model results based on classical approach
of considering only CBOD show significant difference between the model predictions and field measurements suggesting that
NBOD needs to be incorporated for the model development. The dissolved oxygen values calculated using the MSP model and the
CSP model based on overall BOD rate are in close agreement with field measurements and are thus suitable to model DO levels
in the Ravi River. 相似文献
80.
When agricultural lands are no longer used for agriculture and allowed to recover its natural vegetation, soil organic carbon
can accumulate in the soil. Measurements of soil organic carbon and aggregate stability changes under various forms of land
use are needed for the development of sustainable systems. Therefore, comparison of soil samples taken from both agricultural
and nearby area close to land-mined fields where no agricultural practices have been done since 1956 can be a good approach
to evaluate the effects of tillage and agriculture on soil quality. The objective of this study was to compare tillage, cropping
and no tillage effects on some soil-quality parameters. Four different locations along the Turkey–Syria border were selected
to determine effects of tillage and cropping on soil quality. Each location was evaluated separately because of different
soil type and treatments. Comparisons were made between non-tilled and non-cropped fallow since 1956 and adjacent restricted
lands that were tilled about every 2 years but not planted (T) or adjacent lands tilled and planted with wheat and lentil
(P). Three samples were taken from the depths of 0–20 and 20–40 cm each site. Soil organic carbon (SOC), pH ,electrical conductivity,
water soluble Ca++, Mg++, CO3-2{\rm CO}_{3}^{-2} and HCO3-{\rm HCO}_{3}^{-}, extractable potassium (K+) and sodium (Na+), soil texture, ammonium (NH4+{\rm NH}_{4}^{+}–N) and nitrate (NO3–N), extractable phosphorous and soil aggregate stability were determined. While the SOC contents of continuous tillage without
cropping and continuous tillage and cropping were 2.2 and 11.6 g kg−1, respectively, it was 30 g kg−1 in non-tilled and non-planted site. Tillage of soil without the input of any plant material resulted in loss of carbon from
the soil in all sites. Soil extractable NO3−N contents of non-tilled and non-cropped sites were greatest among all treatments. Agricultural practices increased phosphorus
and potassium contents in the soil profile. P2O5 contents of planted soils were approximately 20 to 39 times greater than those of non-tilled and non-cropped soils at different
sites. FTIR spectra showed that never tilled sites had greater phenol, carboxylic acid, amide, aromatic compounds, polysaccharide
and carbohydrates than other treatments. 相似文献