نتایج جستجو برای: co2

تعداد نتایج: 70752  

2001
Jeffrey S. Amthor George W. Koch Jennifer R. Willms David B. Layzell

Elevated CO2, in the dark, is sometimes reported to inhibit leaf respiration, with respiration usually measured as CO2 efflux. Oxygen uptake may be a better gauge of respiration because non-respiratory processes can affect dark CO2 efflux in elevated CO2. Two methods of quantifying O2 uptake indicated that leaf respiration was unaffected by coincident CO2 level in the dark.

Journal: :The European respiratory journal 2001
N G Koulouris P Latsi J Dimitroulis B Jordanoglou M Gaga J Jordanoglou

The lack of methodology for measuring the alveolar carbon dioxide tension (PA,CO2) has forced investigators to make several assumptions, such as that PA,CO2 is equal to end-tidal (PET,CO2) and arterial CO2 tension (Pa,CO2). The present study measured the mean PA,CO2 and Bohr's dead space ratio (Bohr's dead space/tidal volume (VD,Bohr/VT)) during tidal breathing. The method used is a new, simple...

Journal: :Journal of environmental sciences 2015
Sarah Hafeez X Fan Arshad Hussain C F Martín

CO2 is the main greenhouse gas which causes global climatic changes on larger scale. Many techniques have been utilised to capture CO2. Membrane gas separation is a fast growing CO2 capture technique, particularly gas separation by composite membranes. The separation of CO2 by a membrane is not just a process to physically sieve out of CO2 through the controlled membrane pore size. It mainly de...

2014
Sasitorn Hasin Mizue Ohashi Akinori Yamada Yoshiaki Hashimoto Wattanachai Tasen Tomonori Kume Seiki Yamane

Many ant species construct subterranean nests. The presence of their nests may explain soil respiration "hot spots", an important factor in the high CO2 efflux from tropical forests. However, no studies have directly measured CO2 efflux from ant nests. We established 61 experimental plots containing 13 subterranean ant species to evaluate the CO2 efflux from subterranean ant nests in a tropical...

2017
Fuping Jiang Yunze Shen Chuanxin Ma Xiaowen Zhang Weidong Cao Yukui Rui

Concerns over the potential risks of nanomaterials to ecosystem have been raised, as it is highly possible that nanomaterials could be released to the environment and result in adverse effects on living organisms. Carbon dioxide (CO2) is one of the main greenhouse gases. The level of CO2 keeps increasing and subsequently causes a series of environmental problems, especially for agricultural cro...

Journal: :Journal of the American Chemical Society 2017
Tianhan Kai Min Zhou Zhiyao Duan Graeme A Henkelman Allen J Bard

The electrocatalytic reduction of CO2 has been studied extensively and produces a number of products. The initial reaction in the CO2 reduction is often taken to be the 1e formation of the radical anion, CO2•-. However, the electrochemical detection and characterization of CO2•- is challenging because of the short lifetime of CO2•-, which can dimerize and react with proton donors and even mild ...

2013
Zhihong Sun Katja Hüve Vivian Vislap Ülo Niinemets

Isoprene emissions importantly protect plants from heat stress, but the emissions become inhibited by instantaneous increase of [CO2], and it is currently unclear how isoprene-emitting plants cope with future more frequent and severe heat episodes under high [CO2]. Hybrid aspen (Populus tremula x Populus tremuloides) saplings grown under ambient [CO2] of 380 μmol mol(-1) and elevated [CO2] of 7...

Journal: :Journal of the American Mosquito Control Association 2008
Wilhelmine H Meeraus Jennifer S Armistead Jorge R Arias

Aedes albopictus is a potential West Nile virus bridge vector in Northern Virginia; however, information regarding its virus transmission dynamics is limited, as this species is not readily collected in existing traps. This study used 5 replicates of a 5 x 5 Latin square to evaluate the efficiency and effectiveness of 2 novel host-seeking mosquito traps (the BG-Sentinel and the Collapsible Mosq...

2007
A. Engel K. G. Schulz

The influence of seawater carbon dioxide (CO2) concentration on the size distribution of suspended particles (2–60μm) and on phytoplankton abundance was investigated during a mesocosm experiment at the large scale facility (LFS) in Bergen, Norway, in the frame of the Pelagic Ecosystem CO2 Enrichment study (PeECE II). In nine outdoor enclosures the partial pressure of CO2 in seawater was modifie...

رضا عابدینی, فاطره درستی, محمدرضا امیدخواه

در این پژوهش، اثر چارچوب ­های فلزی-آلی NH2-MIL 53 بر خواص گازتراوایی غشای پلیمری پلی(4- متیل-1- پنتین) (PMP) بررسی شده است. از روش ­های مختلفی نظیر FTIR، DSC، SEM و آزمون جذب گاز به همراه آزمون جداسازی CO2/CH4 به حالت گاز خالص و مخلوط گازی برای بررسی آثار گروه عاملی  NH2- بر خواص غشاهای شبکه ترکیبی بهره گرفته شد. نتایج حاصل از DSC نشان­ دهنده افزایش دمای انتقال شیشه­ ای (Tg) غشاها به ازای ازدیا...

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