Determination of an Environmental Background Level of 90Sr in Urine for the Hanford Bioassay Program

2009 ◽  
Vol 97 ◽  
pp. S180-S182 ◽  
Author(s):  
C L. Antonio ◽  
J W. Rivard
Keyword(s):  
Background Level ◽  
Environmental Background

Problems in the Derivation of d-Values from Experimental Digital XRD Patterns

1989 ◽  
Vol 33 ◽  
pp. 285-293 ◽  
Author(s):  
Ron Jenkins ◽  
Monte Nichols
Keyword(s):  
Background Subtraction ◽  
Background Level ◽  
Step Size ◽  
Great Flexibility ◽  
Data Smoothing ◽  
Software Packages ◽  
Counting Time ◽  
Xrd Patterns ◽  
D Values

AbstractMost commercially available, automated powder diffractometers include software packages for the determination of d-values from experimentally recorded digitized patterns. While many of these patterns offer great flexibility to the user, indications from a recent Round-Robin Study [1] are that many users are confused as to the correct use of such parameters as choice of step size and counting time, the degree of data smoothing, peak-hunting parameters, setting of background level, and the consequences of background subtraction and α2 stripping. This paper will reviews these various factors and give some guidelines as to the establishment of optimum conditions.

Determination of Butyltin Compounds in Sediments by GC/MS After Their Conversion to Methyl Derivatives

1997 ◽  
Vol 62 (9) ◽  
pp. 1403-1412 ◽  
Author(s):  
David Milde ◽  
Zbyněk Plzák ◽  
Miloslav Suchánek
Keyword(s):  
Chemical Ionization ◽  
High Selectivity ◽  
Ion Trap ◽  
Background Level ◽  
Mass Detection ◽  
Efficient Separation ◽  
Methyl Derivatives ◽  
Butyltin Compounds ◽  
Hexane Solution

A selective and rapid procedure was developed for the determination of trace amounts of butyltin compounds in sediments by capillary gas chromatography with mass spectrometric detection. Analytes were isolated from the sediment samples by extraction with a methanolic solution of HCl (0.5 mol l-1) followed by reextraction into a hexane solution of tropolone (0.1%). The organotin compounds were converted to the nonpolar methyl derivatives by methylation with a Grignard reagent. The recovery was determined for each step of the procedure. This efficient separation method combined with the ion trap based mass detection ensures a high selectivity even for concentrations approaching the detection limit (0.15 pg for Bu3SnMe) in real sediments. Chemical ionization using acetonitrile as the reaction gas, exhibiting a similar sensitivity of determination and reducing the background level, can serve as a convenient alternative of detection for sediments heavily contaminated by organics. The method was applied to a set of real samples and validated by analysis of a certified reference material.

scholarly journals Environmental Assessment in the Pre-launch Phase of Hayabusa2 for Safety Declaration of Returned Samples From Asteroid (162173) Ryugu: Background Monitoring of Possible Contaminants During Development of the Sampler System

2021 ◽  
Author(s):  
Kanako Sakamoto ◽  
Yoshinori Takano ◽  
Hirotaka Sawada ◽  
Ryuji Okazaki ◽  
Takaaki Noguchi ◽  
...  
Keyword(s):  
Background Level ◽  
Major Elements ◽  
Organic Content ◽  
Inorganic Analysis ◽  
Sample Analysis ◽  
Environmental Assessments ◽  
Pristine Sample ◽  
Launch Site ◽  
Environmental Background ◽  
Static Monitoring

Abstract We report the ground-based environmental assessments during development of the sampler system until the launch of the Hayabusa2 spacecraft. We conducted static monitoring of potential contaminants to assess the environmental cleanliness during (1) laboratory work throughout the development and manufacturing of the sampler devices, (2) installation of the sampler system on the spacecraft, and (3) transportation to the launch site at the JAXA’s Tanegashima Space Center. Major elements and ions detected in our inorganic analysis were sodium (Na), potassium (K), and ionized chloride (Cl–); those were positively correlated with the total organic content and with exposure duration in the range from 101 to 103 nanogram per monitor coupon within a ~30 mm-diameter scale. We confirmed that deposits on the coupon were totally less than the microgram-scale order during manufacturing, installation, and transportation in the pre-launch phase. The present assessment yields a nominal safety declaration for sample analysis of the pristine sample (>5 g) returned from asteroid (162173) Ryugu combined with a highly clean environmental background level. We expect that the Hayabusa2-returned sample from Ryugu without severe and/or unknown contamination will allow us to provide native profiles recorded in the carbonaceous asteroid history.

BioDiff - a neutron diffractometer for protein crystallography

2014 ◽  
Vol 70 (a1) ◽  
pp. C1215-C1215
Author(s):  
Tobias Schrader ◽  
Andreas Ostermann ◽  
Michael Monkenbusch ◽  
Bernhard Laatsch ◽  
Philipp Jüttner ◽  
...  
Keyword(s):  
Neutron Beam ◽  
Pyrolytic Graphite ◽  
Ccd Camera ◽  
Background Level ◽  
Neutron Imaging ◽  
Imaging Plate ◽  
Active Centre ◽  
Joint Project ◽  
Neutron Diffractometer

The research reactor Heinz Maier-Leibnitz (FRM II) is a modern high flux neutron source which feeds some 30 state of the art neutron beam instruments. Currently 24 are operational, others in commissioning or under construction. The newly built neutron single crystal diffractometer BIODIFF is especially designed to collect data from crystals with large unit cells. The main field of application is the structural analysis of proteins, especially the determination of hydrogen atom positions. BIODIFF is a joint project of the Jülich Centre for Neutron Science (JCNS) and the FRM II. Typical scientific questions addressed are the determination of protonation states of amino acid side chains (see e. g. [1,2]) and the characterization of the hydrogen bonding network between the protein active centre and an inhibitor or substrate. BIODIFF is designed as a monochromatic instrument. By using a highly orientated pyrolytic graphite monochromator (PG002) the diffractometer is able to operate in the wavelength range of 2.4 Å to about 5.6 Å. Contaminations of higher order wavelengths are removed by a neutron velocity selector. To cover a large solid angle the main detector of BIODIFF consists of a neutron imaging plate in a cylindrical geometry with online read-out capability. A fast Li/ZnS scintillator CCD camera is available for additional detection abilities. An optical CCD-camera pointing at the sample position is used to quickly align the crystal with respect to the neutron beam. The main advantage of BIODIFF is the possibility to adapt the wavelength to the size of the unit cell of the sample crystal while operating with a clean monochromatic beam that keeps the background level low. BIODIFF is equipped with a standard Oxford Cryosystem "Cryostream 700+" which allows measurements in the temperature regime from 90 K up to 500 K (see Figure underneath).

Environmental background level of cosmic ray produced 22Na

1993 ◽  
Vol 21 (3) ◽  
pp. 213-218 ◽  
Author(s):  
Hideki Tokuyama ◽  
Masaki Oonishi ◽  
Hiroyuki Matsuura
Keyword(s):  
Background Level ◽  
Cosmic Ray ◽  
Environmental Background

scholarly journals New radiocarbon evidence on early rice consumption and farming in South China

The Holocene ◽  
2016 ◽  
Vol 27 (7) ◽  
pp. 1045-1051 ◽  
Author(s):  
Xiaoyan Yang ◽  
Weiwei Wang ◽  
Yijie Zhuang ◽  
Zhao Li ◽  
Zhikun Ma ◽  
...  
Keyword(s):  
South China ◽  
Late Holocene ◽  
Rice Farming ◽  
Radiocarbon Dates ◽  
Plant Remains ◽  
Environmental Background ◽  
Rice Consumption ◽  
The Pearl River ◽  
Exact Timing

While the possibility of indigenous rice cultivation cannot be entirely ruled out, there is increasing evidence suggesting that rice farming was introduced to South China during the late-Holocene. However, determination of the exact timing of the spread of rice farming to South China is fraught with the lack of reliable radiocarbon dates. In this article, we present 15 new AMS 14C dates of charred plant remains recovered from late-Holocene sites of Shixia and Guye in Guangdong Province of South China. Our new AMS 14C dates suggest a later arrival of rice farming in the Pearl River Delta than previously thought. These new AMS 14C dates will shed new lights to an improved understanding of the environmental background and ecology of the southward spread of rice farming.

scholarly journals Chemical Composition of Scots Pine Bark as a Bioindicator of Environmental Quality in Riga, Latvia / Priežu Mizu ķīmiskais Sastāvs Kā Vides Stāvokļa Bioindikators Rīgā (Latvija)

2015 ◽  
Vol 69 (3) ◽  
pp. 87-97
Author(s):  
Gunta Čekstere ◽  
Māris Laiviņš ◽  
Anita Osvalde
Keyword(s):  
Chemical Composition ◽  
Environmental Quality ◽  
Rural Areas ◽  
Chemical Elements ◽  
Urban Forests ◽  
Background Level ◽  
Pine Bark ◽  
Element Concentrations ◽  
Building Area

Abstract The chemical composition of pine bark was used for the determination of environmental quality in Rīga. Bark samples were collected at 54 sites in Rīga differing in vegetation and building area characteristics (urban forests, parks and cemeteries, dwelling houses, and streets and railway zones) and at 52 sites from rural areas in Latvia (background level). Concentrations of Ca, Mg, Na, K, Fe, Mn, Zn, Ni, Cu, Cd, Pb, and pH was determined in the samples. The results showed significantly higher concentrations of chemical elements in pine bark collected in Rīga, compared to background levels: Fe and Cu concentrations three times higher, and other elements - up to 1.8 times. The highest element concentrations in Rīga were near streets (Sarkandaugava, Jaunmīlgrāvis, Daugavgrīva, Čiekurkalns, Imanta area, etc.). Element concentration and pH was significantly dependent on the distance from the closest street. The lowest element concentrations were found in urban forests (Jugla, Biķernieki, Beberbeķi) and parks and cemeteries (I Forest Cemetery, Jaunciema Cemetery). Mežaparks (forest), Sarkandaugava, Jaunmīlgrāvis, and Vecmīlgrāvis together formed the most polluted area in Rīga due to the close location near and downwind from the harbour.

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