نتایج جستجو برای: elemental carbon

تعداد نتایج: 299121  

Journal: :The Science of the total environment 2011
Manoranjan Sahu Shaohua Hu Patrick H Ryan Grace Le Masters Sergey A Grinshpun Judith C Chow Pratim Biswas

Exposure to traffic-related pollution during childhood has been associated with asthma exacerbation, and asthma incidence. The objective of the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS) is to determine if the development of allergic and respiratory disease is associated with exposure to diesel engine exhaust particles. A detailed receptor model analyses was undertaken by app...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت دبیر شهید رجایی - دانشکده علوم پایه 1391

این پژوهش به اکسید اسیون متانول در محیط قلیایی می پردازد. برای این منظور ابتدا ترسیب ذرات نیکل، پلاتین و نیکل – پلاتین بر روی زیر لایه کاغذ کربنی به روش آبکاری به شیوه ی جریان مستقیم استفاده شد. در ادامه مورفولوژی پوشش های ذرات فلزی بر روی کاغذ کربنی از طریق میکروسکوپ الکترونی روبشی بررسی و مطالعه شد. سپس خواص کاتالیستی الکترودها ی حاصل در اکسیداسیون متانول با استفاده از روشهای الکتروشیمیایی هم...

Journal: :Journal of Geophysical Research 2006

2016
Adam C Martiny Lanying Ma Céline Mouginot Jeremy W Chandler Erik R Zinser

Variability in plankton elemental requirements can be important for global ocean biogeochemistry but we currently have a limited understanding of how ocean temperature influences the plankton C/N/P ratio. Multiple studies have put forward a 'translation-compensation' hypothesis to describe the positive relationship between temperature and plankton N/P or C/P as cells should have lower demand fo...

This paper presents a systematic study of the surface chemistry, porous texture and adsorptive characteristics of prepared new activated carbon using Persian mesquite grain. Several techniques and methodologies such as, proximate analysis, N2 adsorption–desorption isotherms, scanning electron microscope (SEM), Fourier transform infrared spectroscopy(FT-IR), X-ray Diffraction (XRD), X-ray photoe...

2013
K. G. Schulz T. Boxhammer R. G. J. Bellerby J. Büdenbender A. Engel S. A. Krug

Recent studies on the impacts of ocean acidification on pelagic communities have identified changes in carbon to nutrient dynamics with related shifts in elemental stoichiometry. In principle, mesocosm experiments provide the opportunity of determining temporal dynamics of all relevant carbon and nutrient pools and, thus, calculating elemental budgets. In practice, attempts to budget mesocosm e...

Journal: :Journal of the Air & Waste Management Association 2003
Nehzat Motallebi Hien Tran Bart E Croes Lawrence C Larsen

This paper analyzes day-of-week variations in concentrations of particulate matter (PM) in California. Because volatile organic compounds (VOCs) and oxides of nitrogen (NOx) are not only precursors of ozone (O3) but also of secondary PM, it is useful to know whether the variations by day of week in these precursors are also evident in PM data. Concentrations of PM < or = 10 microm (PM10) and < ...

2011
J. Genberg M. Hyder K. Stenström R. Bergström D. Simpson E. O. Fors

A one-year study was performed at the Vavihill background station in southern Sweden to estimate the anthropogenic contribution to the carbonaceous aerosol. Weekly samples of the particulate matter PM10 were collected on quartz filters, and the amounts of organic carbon, elemental carbon, radiocarbon (14C) and levoglucosan were measured. This approach enabled source apportionment of the total c...

2005
John G. Watson Judith C. Chow Antony Chen

Many different thermal, optical, and thermal/optical carbon analysis methods for organic carbon (OC), elemental carbon (EC) or black carbon (BC) have been applied throughout the world to evaluate visibility and the Earth’s radiation balance. Dozens of intermethod and interlaboratory comparison studies have been conducted. Several of these studies are catalogued and summarized here. BC or EC con...

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