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131.
A combustion-driven flow reactor was used to examine the formation of chlorinated and non-chlorinated species from the thermal oxidation of chlorobenzene under post-flame conditions. Temperature varied from 725 to 1000 K, while the equivalence ratio was held constant at 0.5. Significant quantities of chlorinated intermediates, vinyl chloride and chlorophenol, were measured. A dominant C-Cl scission destruction pathway seen in pyrolytic studies was not observed. Instead, hydrogen-abstraction reactions prevailed, leading to high concentrations of chlorinated byproducts. The thermal oxidation of benzene was also investigated for comparison. Chemical kinetic modeling of benzene and chlorobenzene was used to explore reaction pathways. Two chlorobenzene models were developed to test the hypothesis that chlorobenzene oxidation follows a CO-expulsion breakdown pathway similar to that of benzene. For the temperatures and equivalence ratio studied, hydrogen abstraction by hydroxyl radicals dominates the initial destruction of both benzene and chlorobenzene. Chlorinated byproducts (i.e., chlorophenol and vinyl chloride) were formed from chlorobenzene oxidation in similar quantities and at similar temperatures to their respective analogue formed during benzene oxidation (i.e., phenol and ethylene). 相似文献
132.
133.
Ophidiaster granifer Lütken is a small cryptic coral reef asteroid found in the Indo-West Pacific. Its mode of reproduction, shown by aquarium observations and gonad histology, is parthenogenetic. This is the first confirmation of natural parthenogenesis in the phylum Echinodermata, despite many studies showing artificial parthenogenesis in echinoderms. Populations of O. granifer from Micronesia, New Guinea and the Great Barrier Reef consisted only of females: no testes or spermatogenesis were found in any individual at any stage of gonad development of ca 400 individuals. Regular year-round population censuses at Guam, Micronesia, revealed a distinct 0-year class which grew to sexual maturity in two years. There was an annual reproductive cycle with apparently-synchronous spawning in early winter. The large eggs, ca 0.6 mm diameter, develop into lecithotrophic larvae. Some larvae are planktonic, while some remain attached under the rocks. The latter develop through metamorphosis in situ. Parthenogenetic reproduction leading to both stationary and dispersed larvae may be related to the low fecundity and low population densities of this small asteroid. 相似文献
134.
Treatment of effluent from re‐refined lubricating oils by combined processes of coagulation,flocculation, and Fenton process 下载免费PDF全文
Lucas Pisoni da Silva Silvio Roberto Taffarel Fernanda Rosa da Silveira Fagner Tafarel Campos de Sá Luís Felipe Silva Oliveira 《环境质量管理》2018,27(4):135-141
This work examines the possibility and the potential application of physicochemical processes (coagulation and flocculation) and advanced oxidative processes (Fenton Process) in the treatment of effluents from the re‐refining of used lubricating oils. 相似文献
135.
Alexandre Marco da Silva Lucas Hubacek Tsuchiya Pablo Bettio Mendes Thiago Philipe de Camargo e Timo Artemio Cerd 《环境质量管理》2019,29(1):125-137
Soil erosion and the invasion of exotic plant species are major constraints to achieve sustainable development around the world. Currently, we find few products devoted concomitantly to combatting soil erosion as well as the establishment of unwanted exotic plants. In this paper, we introduce a new product, called herein a bioblanket, that protects the soil and impedes the establishment of exotic plant species. This product is of simple design, and to manufacture it, we use two biodegradable materials: jute tissue and grass wastes. We designed this product to combat soil erosion and the germination and establishment of new, unwanted, invasive plant species. In this paper, we describe our evaluation of how successful this product was in terms of improving the chemical attributes of soil. We also identified the product's potentialities and weaknesses by means of strengths, weaknesses, opportunities, and threats (SWOT) analysis. The bioblanket ameliorated the chemical attributes of the soil, as evidenced especially by the neutralization of acidity (8.5%) and aluminum toxicity (33%), and by an increment in nutrients concentration. We argue that after adequate treatment and management, the residues of plants that are normally considered unwanted materials can be transformed into a raw material to control the propagation of unwanted plant species, and concomitantly control soil erosion while improving the chemical conditions of the soil. The improvement of the soil chemical attributes was one of the main positive effects reported through the SWOT analysis. In addition, the SWOT analysis revealed some features that need improvement in future generations of the product, but we argue that these features do not impede the benefits for the use of the product in its present form. 相似文献
136.
Tim?Lucas Elizabeth?K.?O‘Brien Tom?Cribb Bernard?M.?DegnanEmail author 《Marine Biology》2005,148(2):285-292
Approximately 1–2% of the tropical abalone Haliotis asinina inhabiting Heron Island Reef are infected with opecoelid digeneans. These largely inhabit the haemocoel surrounding the cerebral ganglia and digestive gland–gonad complex, and infected abalone typically have significantly reduced or ablated gonads. Observations of infected abalone reveal two distinct cercarial emergence patterns, one which correlates tightly with the abalone’s highly regular and synchronous fortnightly spawning cycle, and the other which occurs in a circadian pattern. The former appears to be a novel emergence strategy not previously observed in digeneans. While the cercariae in all abalone are morphologically indistinguishable, comparison of sequences from the internal transcribed spacer 2 (ITS 2) region of the ribosomal DNA reveals a 5.7% difference between cercariae displaying different emergence patterns, indicating these are two distinct species that probably belong to the same genus. The ITS 2 sequences of the species with the daily emergence pattern are identical to that of an undescribed adult opecoelid from the gut of the barramundi cod, Cromileptes altivelis. Combined molecular, morphological and emergence data suggest that while these opecoelid cercariae use the same first intermediate host and are closely related species—members of the genus Allopodocotyle—they fill different ecological niches that are likely to include different definitive hosts. 相似文献
137.
Biochemical characterization of purified carbonic anhydrase from the octocoral Leptogorgia virgulata 总被引:2,自引:0,他引:2
Carbonic anhydrase (CA) has been isolated and purified from the octocoral Leptogorgia virgulata (Lamarck) in an effort to investigate its role in the mineralization and demineralization of spicules and other calcified hard tissues. Affinity-chromatography using Prontosil-derivatized carboxymethylcellulose (CM) Bio-Gel A provided a one-step purification for 30 kdalton polypeptides with carbonic anhydrase activity. Four distinct polypeptides (designated , , , and ) are separated from one another at this molecular weight by two-dimensional gel electrophoresis. The specific activity of the L. virgulata CA is on average 57.5±1.5 U g-1, is inhibitable by 10-6
M acetazolamide, and is unaffected by 5mM dithiotheitol. The amino acid composition of these polypeptides is similar to that of mammal, bird, reptile, fish and arthropod species. Antiserum made against the L. virgulata CA reacts specifically with the 30 kdalton polypeptides in western blots, and crossreacts with human CA I and II. Antiserum against avian CA II crossreacts with the L. virgulata 30 kdalton polypeptides. This is the first report of the characterization of a purified CA from an octocoral, and production of a CA antiserum to a species in the phylum Cnidaria. 相似文献
138.
Christina Skarpe Per Arild Aarrestad Harry P. Andreassen Shivcharn S. Dhillion Thatayaone Dimakatso Johan T. du Toit Duncan J. Halley Hkan Hytteborn Shimane Makhabu Moses Mari Wilson Marokane Gaseitsiwe Masunga Ditshoswane Modise Stein R. Moe Rapelang Mojaphoko David Mosugelo Sekgowa Motsumi Gosiame Neo-Mahupeleng Mpho Ramotadima Lucas Rutina Lettie Sechele Thato B. Sejoe Sigbjrn Stokke Jon E. Swenson Cyril Taolo Mark Van 《Ambio-人类环境杂志》2004,33(6):254-260
博茨瓦纳北部及其毗邻地区分布着世界上最大的非洲象种群(Loxodonta africana),而在100年前,由于过度捕猎,大象的种群数量极为稀少. 相似文献
139.
A series of hypotheses on the role of the individual administrator in famine relief are proposed and three are examined with respect to case studies of famines in India (1896 and 1906–1907), Uganda (1908) and Lombok (1940). While the evidence is not conclusive, the focus upon the role of the individual administrator offers additional insights into the compexities of official response to famines. 相似文献
140.
Gast n Azziz Mat as Gim nez H ctor Romero Patricia M. Valdespino-Castillo Luisa I. Falc n Lucas A. M. Ruberto Walter P. Mac Cormack Silvia Batista 《Frontiers of Environmental Science & Engineering》2019,13(3):44