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321.
Chandra Nath Shiv G. Kapoor Richard E. DeVor Anil K. Srivastava Jon Iverson 《Journal of Manufacturing Processes》2012,14(4):452-459
Tool life has been a vital issue in machining titanium alloys. Recently, an atomization-based cutting fluid (ACF) application has been found to be an effective approach for cooling and lubrication in micromachining operations. In this study, an ACF spray system is developed for macro-scale turning of Ti–6Al–4V. The spray system is designed to minimize interaction between the fluid droplets, and the gas nozzle to control the divergence of the fluid droplets. Experiments are conducted to study the effect of five specific ACF spray parameters including fluid flow rate, spray distance, impingement angle, and type and pressure level of the droplet carrier gas on cutting forces, tool life, and chip characteristics. It has been observed that the combination of lower pressure (150 psi) air-mixed CO2 with a higher flow rate (20 ml/min) and a larger spray distance (35 mm) produces a significantly longer tool life and broken chips. The results also reveal that the ACF spray system can extend tool life up to 40–50% over flood cooling. 相似文献
322.
J. S. Rice R. H. Moss P. J. Runci K. L. Anderson E. L. Malone 《Mitigation and Adaptation Strategies for Global Change》2012,17(7):805-819
A new modeling effort exploring the opportunities, constraints, and interactions between mitigation and adaptation at regional scale is utilizing stakeholder engagement in an innovative approach to guide model development and demonstration, including uncertainty characterization, to effectively inform regional decision making. This project, the integrated Regional Earth System Model (iRESM), employs structured stakeholder interactions and literature reviews to identify the most relevant adaptation and mitigation alternatives and decision criteria for each regional application of the framework. The information is used to identify important model capabilities and to provide a focus for numerical experiments. This paper presents the stakeholder research results from the first iRESM pilot region. The pilot region includes the Great Lakes Basin in the Midwest portion of the United States as well as other contiguous states. This geographic area (14 states in total) permits cohesive modeling of hydrologic systems while also providing strong gradients in climate, demography, land cover/land use, and energy supply and demand. The results from the stakeholder research indicate that, for this region, iRESM should prioritize addressing adaptation alternatives in the water resources, urban infrastructure, and agriculture sectors, including water conservation, expanded water quality monitoring, altered reservoir releases, lowered water intakes, urban infrastructure upgrades, increased electric power reserves in urban areas, and land use management/crop selection changes. For mitigation in this region, the stakeholder research implies that iRESM should focus on policies affecting the penetration of renewable energy technologies, and the costs and effectiveness of energy efficiency, bioenergy production, wind energy, and carbon capture and sequestration. 相似文献
323.
A juvenile lizard specimen with well-preserved skin impressions from the Upper Jurassic/Lower Cretaceous of Daohugou, Inner Mongolia, China 总被引:1,自引:0,他引:1
Lizards are now relatively well known from the Yixian Formation of northeastern China. In this study, we describe a juvenile
lizard from a fossil horizon at Daohugou, Inner Mongolia. These beds predate the Yixian Formation, and are probably Late Jurassic
or earliest Cretaceous in age. The new specimen thus documents the first lizard material from the Daohugou locality and is
the earliest lizard skeleton from China. Comparisons with developmental stages of modern lizards suggest the Daohugou lizard
is a hatchling. Although tiny, the specimen is notable in preserving exquisite skin impressions showing the variation in scalation
across the body, the shape and position of the cloacal outlet, and details of the manus and pes. These are the earliest recorded
lepidosaurian skin traces. In its general proportions and the possession of paired frontals, the small Daohugou lizard resembles
both the Yixian taxon Yabeinosaurus tenuis and the questionable Jeholacerta formosa, but it differs from the latter in scalation and, based on other characters, may be distinct from both. 相似文献
324.
M.A. Bustamante D. Said-Pullicino E. Agulló J. Andreu C. Paredes R. Moral 《Agriculture, ecosystems & environment》2011,140(1-2):80-87
The effects on different physico-chemical, chemical and biological soil properties of the incorporation of different organic materials into a calcareous vineyard soil were studied in an experiment during three growing seasons. The organic materials used were sheep manure and four composts derived from the treatment of winery and distillery wastes. A multivariate technique, factor analysis (FA), was also used for interpreting the data obtained from the samplings carried out throughout the three vine growing seasons. The application of the organic materials induced an increase in the activity of the soil microorganisms and in the soil macro and micronutrient contents, as well as a slow release of inorganic N. Through FA of the soil properties studied, three factors that explained 74.7% of the variability were established and the effects of the treatments after the whole experimental period were assessed. 相似文献
325.
Tarasiuk N Koviazina E Kubareviciene V Shliahtich E 《Journal of environmental radioactivity》2007,93(2):100-118
Radiocesium vertical profiles in organics-rich sediments of running shallow eutrophic Lake Juodis (Lithuania) were studied in relation to seasonal variations of vertical profiles (in water column and sediments) of standard variables (pH, redox potential, temperature, oxygen concentrations, conductivity). It is shown that the sedimentation rate, radiocesium mobility and its vertical profiles in sediments are controlled by the vital cycle (processes of the growth, accumulation and decomposition) of green algae covering the main bottom areas of the lake. It is also shown that calcite deposits are formed in the shallow bottom areas that are oxygenated throughout the year because of the photosynthetic activity of the green algae covering the sediment. Formation of the calcite coatings on freshly accumulated organics is remarkable for causing elevated densities of sediment solids in the upper part of the respective vertical profiles. These calcite deposits behave as a barrier for radiocesium backward flux to the bottom water making the respective bottom areas a radionuclide sink. Together with the jelly-structured sediments lying below these deposits, the calcite preserves the shape of the primary radiocesium vertical profiles formed due to free-ion diffusion after the deposition event. It was determined that bottom areas anaerobic in winter are the main radiocesium source in the water column and cause characteristic radiocesium redistribution in surface sediments. 相似文献
326.
Alvarez-Muñoz D Lara-Martín PA Blasco J Gómez-Parra A González-Mazo E 《Environment international》2007,33(4):565-570
The presence of linear alkylbenzene sulfonates (LAS) and their degradation intermediates, sulfophenylcarboxylic acids (SPCs), with concentrations up to 100 ppb has been found in surface waters taken from the estuary of the river Guadalete (Cádiz, SW of Spain). Higher concentrations were found at the sampling site located adjacent to the discharge outlet of a wastewater treatment plant (WWTP). The concentrations decreased downstream to a few ppb as a result of dilution, sorption, and degradation processes, which were taking place along the estuary. Once the presence of both xenobiotics was confirmed in the environment, an in vivo assay was conducted to study their biotransformation and effects in the benthic fish Solea senegalensis. A flow-through system was employed, consisting of an exposure phase (120 h) with environmental levels of the surfactant (200, 500 and 800 microg/L of 2?C(10)LAS), followed by a depuration stage (72 h). The generation of SPCs has been quantified during these phases in both water and fish, with LAS biotransformation shown in all cases. The antioxidant enzymes catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR), the phase II enzyme glutathione S-transferase (GST), and the phase III acid and alkaline phosphatases (AcP, ALP) were also estimated and utilized as biomarkers. 相似文献
327.
The phenetic structure of natural and urbanized populations of the terrestrial snail Cepaea vindobonensis has been studied with respect to polymorphism in the shell-band color and pattern. It is noted that C. vindobonensis snails populating different artificial habitats in the city of Nikolaev and its suburbs are characterized by a higher level of both intra-and interpopulation diversity with respect to the type of this polymorphism. In addition, urban populations show a very wide range of variation in the frequencies of particular morphs or their groups. Conversely, natural populations are characterized by a more uniform frequency structure with respect to polymorphism of the shell banding pattern. 相似文献
328.
329.
Cristina E. Almeida-Naranjo Bryan Morillo María B. Aldás Nicole Garcés Alexis Debut Victor H. Guerrero 《补救:环境净化治理成本、技术与工艺杂志》2023,33(2):135-150
The removal of heavy metals from wastewater has become a global challenge, which demands the continuous study of efficient and low-cost treatment alternatives such as adsorption. In this research, the removal of zinc was evaluated using batch adsorption processes with nonconventional materials such as graphene oxide (GO), magnetite (MG), and their composites (GO:MG), formulated with three weight ratios (2:1, 1:1, and 1:2). Graphene was synthesized by the modified Marcano method, using pencil lead graphite as a precursor. MG and the composites were synthesized by chemical coprecipitation of ferrous sulfate and ferric chloride. The materials were characterized by Raman and Fourier transform infrared spectroscopies, scanning electron microscopy, X-ray diffraction, and the Brunauer–Emmett–Teller method to determine the functional groups, microstructural and morphological characteristics, and specific surface area. Batch adsorption tests were carried out to optimize the adsorbent dose and contact time with zinc solutions of 10 ppm. Zinc adsorption reached equilibrium at 2 h, with an optimal dose between 0.25 and 1.0 g/L. The maximum zinc removal efficiencies/adsorption capacities were 98.6%/165.6, 83.4%/47.6, 83.5%/21.9, 72.8%/19.9, and 82.2%/9.25 mg/g using GO, 2GO:1MG, 1GO:1MG, 1GO:2MG, and MG, respectively. Furthermore, the analysis of the isotherm and adsorption kinetics models determined that the adsorption processes using MG and the composites fit the Sips and pseudo-second-order models. 相似文献
330.
Russian Journal of Ecology - The long-term dynamics (over more than 70 years) of pike infection by cestodes Triaenophorus crassus and T. nodulosus in the Rybinsk Reservoir (the Volga River) has... 相似文献