排序方式: 共有16条查询结果,搜索用时 500 毫秒
11.
Coal bottom ash (CBA) and fly ash (FA) are by-products of thermal power plants. Granulated blast-furnace slag (GBFS) is developed during iron production in iron and steel plants. This research was conducted to evaluate the compressive strength property and some durability characteristics of concrete incorporating FA, CBA, and GBFS. FA is used as an effective partial cement replacement; CBA and GBFS are used as partial replacement for fine aggregate without grinding. Water absorption capacity, unit weight and compressive strengths in 7, 28, and 90-day ages were assessed experimentally. For these experiments, concrete specimens were produced in the laboratory in appropriate shapes. The samples are divided into two main categories: M1, which incorporated CBA and GBFS; and M2, which incorporated FA, CBA, and GBFS. Remarkable decreases are observed in compressive strength and water absorption capacity of the concrete; bulk density of the concrete is also decreased. It can be concluded that if the content of CBA and GBFS is limited to a reasonable amount, the small decreases in strength can be accepted for low strength concrete works. 相似文献
12.
The bio-hydrogen generation potential of sugar industry wastes was investigated. In the first part of the study, acidogenic anaerobic culture was enriched from the mixed anaerobic culture (MAC) through acidification of glucose. In the second part of the study, glucose acclimated acidogenic seed was used, along with the indigenous microorganisms, MAC, 2-bromoethanesulfonate treated MAC and heat treated MAC. Two different COD levels (4.5 and 30 g/L COD) were investigated for each culture type. Reactors with initial COD concentration of 4.5 g/L had higher H2 yields (20.3–87.7 mL H2/g COD) than the reactors with initial COD concentration of 30 g/L (0.9–16.6 mL H2/g COD). The 2-bromoethanesulfonate and heat treatment of MAC inhibited the methanogenic activity, but did not increase the H2 production yield. The maximum H2 production (87.7 mL H2/g COD) and minimum methanogenic activity were observed in the unseeded reactor with 4.5 g/L of initial COD. 相似文献
13.
Ozkan Burhan Akcaoz Handan 《Mitigation and Adaptation Strategies for Global Change》2002,7(4):367-380
This study aims to identify therelationship between the climatic variablesand yields of three crops (wheat (Triticum aestivum L.), maize (Zeamays L.) and cotton (Gossypiumhirsitum L.) in the Cukurova region ofTurkey. In the study, time series data wereused to analyse crop yields across variousclimate factors for the period 1975 to1999. The climatic variables were arrangedaccording to phonological periods of theexamined crops such as planting, floweringand harvesting time. A linear perturbationmodel (LPM) was used for the identificationof the role of climate variables. 27climatic factors were considered asexplanatory variables in the model. Astepwise selection method in the selectionand introduction of independent variableswas used for regression equation for wheat,maize and cotton. The results of the linearperturbation model (LPM) showed that theR2 values for wheat, maize and cottonwere found 46.1%, 57.2% and 74.5%,respectively. The highest variationcoefficient (CV) was found in maizeproduction (43.4%) followed by cotton(23.14%) and wheat (15.29%). The mostsignificant climatic factor affectingdeviations in crop yields is related intemperature at planting, flowering andharvesting time. It is suggested thatfarmers would be better off with theapplying adaptation measurements. Therefore, policy makers should focusefforts on reducing production risksproviding climatic information anddeveloping risk management institutions. 相似文献
14.
The concentration of dissolved oxygen is an important indicator of water quality because aquatic life lives on the dissolved
oxygen in the water. Aeration can increase dissolved oxygen when levels become deficient. Hydraulic structures can significantly
improve dissolved oxygen levels by creating turbulent conditions where small air bubbles are carried into the bulk of the
flow. Recent researches have focused on developing measurement and predictive techniques for oxygen transfer at hydraulic
structures to maintain and enhance water quality. However, reviewing existing studies on aeration performance of hydraulic
structures, it seems that there are not too many studies on venturi aeration. The present paper shows applications of venturi
principle to water aeration systems. The aeration characteristics of venturi nozzle, venturi conduit and venturi weir are
analyzed. The results indicate that venturi aeration might contribute significantly to air entrainment and aeration efficiency.
Therefore, venturi device can be used as highly effective aerator in aeration processes. 相似文献
15.
Evren Tunca Esra Üçüncü Bedri Kurtuluş Alper Devrim Ozkan Sibel Atasagun 《Chemistry and Ecology》2013,29(8):754-769
This study aims to determine the extent of metal pollution in Lake Yeniça?a (Bolu, Turkey) by investigating the accumulation trends of five metals (Al, Cu, Fe, Ni and Zn) and a metalloid (As) in gills, exoskeleton, hepatopancreas and abdominal muscles of the freshwater crayfish Astacus leptodactylus. Principal component analysis (PCA), cluster analysis (CA), correlation analysis and analysis of variance (ANOVA) were utilised to determine the accumulation profiles of each element over four seasons. The greatest element accumulation was found to occur in the gills. All elements in exoskeletal tissue displayed positive correlations with each other, a similar trend was also observed in the hepatopancreas samples. Strong (r=0.868) and very strong (r=0.960) positive correlations were found between the accumulations of Al and Fe in gills and the exoskeleton, respectively. Correlations in tissue accumulation rates are discussed in the context of metabolic roles and impacts associated with the elements tested. Elemental compositions of Yeniça?a water and sediment samples were also investigated to determine whether the composition of the surrounding environment matches the metal accumulation trends of tissue samples. We demonstrate that, by the criteria set by the United States Environmental Protection Agency, Lake Yeniça?a is heavily polluted in terms of As and Ni. 相似文献
16.
Kayar Fatih Doymus Meryem Ozkan Hakan Arslan Nazli Pinar Adiguzel Ahmet Taskin Mesut 《Journal of Polymers and the Environment》2022,30(9):3598-3608
Journal of Polymers and the Environment - Fungi are accepted as novel sources of chitinous materials. The present study was performed to produce chitinous material from locally isolated Penicillium... 相似文献