Center for Monitoring Research

Arlington, VA, United States

Center for Monitoring Research

Arlington, VA, United States

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Thakur P.,Center for Monitoring Research | Mulholland G.P.,Center for Monitoring Research
Applied Radiation and Isotopes | Year: 2012

A number of analytical methods has been developed and used for the determination of neptunium in environmental and nuclear fuel samples using alpha, ICP-MS spectrometry, and other analytical techniques. This review summarizes and discusses development of the radiochemical procedures for separation of neptunium (Np), since the beginning of the nuclear industry, followed by a more detailed discussion on recent trends in the separation of neptunium. This article also highlights the progress in analytical methods and issues associated with the determination of neptunium in environmental samples. © 2012.


Thakur P.,Center for Monitoring Research
Journal of Environmental Radioactivity | Year: 2016

After almost 15 years of operations, the Waste Isolation Pilot Plant (WIPP) had one of its waste drums breach underground as a result of a runaway chemical reaction in the waste it contained. This incident occurred on February 14, 2014. Moderate levels of radioactivity were released into the underground air. A small portion of the contaminated underground air also escaped to the surface through the ventilation system and was detected approximately 1 km away from the facility. According to the source term estimation, the actual amount of radioactivity released from the WIPP site was less than 1.5 mCi. The highest activity detected on the surface was 115.2 μBq/m3 for 241Am and 10.2 μBq/m3 for 239+240Pu at a sampling station located 91 m away from the underground air exhaust point and 81.4 μBq/m3 of 241Am and 5.8 μBq/m3 of 239+240Pu at a monitoring station located approximately 1 km northwest of the WIPP facility. The dominant radionuclides released were americium and plutonium, in a ratio that matches the content of the breached drum. Air monitoring across the WIPP site intensified following the first reports of radiation detection underground to determine the extent of impact to WIPP personnel, the public, and the environment. In this paper, the early stage monitoring data collected by an independent monitoring program conducted by the Carlsbad Environmental Monitoring & Research Center (CEMRC) and an oversight monitoring program conducted by the WIPP's management and operating contractor, the Nuclear Waste Partnership (NWP) LLC were utilized to estimate the actual amount of radioactivity released from the WIPP underground. The Am and Pu isotope ratios were measured and used to support the hypothesis that the release came from one drum identified as having breached that represents a specific waste stream with this radionuclide ratio in its inventory. This failed drum underwent a heat and gas producing reaction that overpowered its vent and lifted its lid to allow release of waste into the underground air. © 2015 Elsevier Ltd.


Bollmeyer C.,Center for Monitoring Research | Hense A.,University of Bonn
Climate Dynamics | Year: 2014

The vertically integrated horizontal energy transports and the vertically integrated vertical energy flux divergence from ERA-40 and ISCCP are not in balance assuming a stationary climate as a time mean over several years. The reasons are the inherent uncertainties in each of the respective data sets. We therefore modify them using a variational approach with a discretization in spherical harmonics to obtain consistent values. The variational approach only modifies the smaller yet more uncertain divergent part of the flow, leaving the large rotational part untouched. From these consistent fields we can calculate posterior covariance matrices of the vertically integrated horizontal energy transport and the vertically integrated vertical energy flux divergence, providing a measure of the uncertainty of the previous calculation. We are able to use these posterior covariance matrices to give an estimate of the uncertainty of the zonally and vertically integrated meridional energy transport, which is about 0.25 PW in the tropics and 0.04 PW in high latitudes, as well as for the vertical energy flux divergence of the atmosphere, which ranges from 2.5 to 5 W/m2 in the tropics to 15-17 W/m2 in high latitudes. © 2014 Springer-Verlag Berlin Heidelberg.


Phenological models based on degree-day accumulation have been developed to support the integrated pest management of many insects. Most of these models are based on linear relationships between temperature and development, and on daily time step simulations using daily minimum and maximum temperatures. This approach represents an approximation that does not take into account the insect physiological response to temperature, and daily temperature fluctuations. The objective of this work has been to develop a phenological model for the European corn borer (ECB) based on the insect physiological response to temperature and running at an hourly time step. Two modeling solutions based on the same generic compartmental system have been compared: the first based on a physiologically based relationship between temperature and development, and using hourly derived temperatures as input (HNL modeling solution); and the second based on a linear relationship between temperature and degree-day accumulation and using daily temperature (DL modeling solution). The two approaches have been compared using ECB moth capture data from the Piemonte region in Northern Italy. The HNL modeling solution showed the best results for all the accuracy indicators. The DL modeling solution showed a tendency to anticipate ECB phenological development too early. This tendency is attributable to the linear relationship between temperature and development, which does not take into account (1) the decline of this relationship at high temperatures, and (2) the daily fluctuation of temperature. As a consequence, degree-days accumulation is accelerated in the DL modeling solution and the phenological development anticipated. © 2011 ISB.


Alparone A.,Center for Monitoring Research | Librando V.,Center for Monitoring Research
Monatshefte fur Chemie | Year: 2012

Molecular geometries, nucleus independent chemical shifts, electronic, infrared and Raman spectra, vertical ionization energy and electron affinity, dipole moment, and electronic polarizabilities of 3-nitro-6-aza-benzo[a]pyrene and its N-oxide derivative were calculated for the gas phase using semiempirical and density functional theory. The influence of the N-oxidation on structural, electronic, and spectroscopic propertiesisdiscussed. The infrared spectral region around 1,300 cm -1 involving the azabenzene N-O and the NO 2 stretching vibrations is potentially useful to distinguish 3-nitro-6-azabenzo[a]pyrene from its N-oxide derivative. The calculated vertical ionization energy for 3-nitro-6-azabenzo[a]pyrene N-oxide is smaller than that of its parent compound, whereas the vertical electron affinity is higher in agreement with the experimental electrochemical reduction potentials. Both dipole moment and polarizability increase on passing from 3-nitro-6-azabenzo[a] pyrene to its N-oxide derivative, the contribution from the N-O bond formation being substantial. The electric property enhancements are explained through atomic charges and spectral shifts. Present results support the higher mutagenic activity for the N-oxide derivative in comparison with its parent compound. © 2012 Springer-Verlag.


Thakur P.,Center for Monitoring Research | Ballard S.,Center for Monitoring Research | Nelson R.,Carlsbad Field Office
Science of the Total Environment | Year: 2013

The Great East Japan Earthquake and tsunami on March 11, 2011 resulted in the tragic accident at the Fukushima Nuclear Power Plant (NPP) and subsequently uncontrolled release of radioactive contaminants into the atmosphere. This review article attempts to compile and interpret data collected by various national and international monitoring networks in response to the Fukushima releases across the northern hemisphere. The majority of the releases occurred during the period March 12-22 with a maximum release phase from March 14-17, 2011. The radioactivity released was dominated by volatile fission products including isotopes of the noble gases (xenon and krypton), iodine, cesium, and tellurium. The radioactive gases and particles released in the accident were dispersed over the middle latitudes of the entire northern hemisphere and for the first time also measured in the southern Hemisphere. Isotopes of iodine and cesium were detected in air, water, milk and food samples collected across the entire northern hemisphere. Elevated levels of fission products were detected from March to May 2011 at many locations over the northern hemisphere.This article focuses on the most prevalent cesium and iodine isotopes, but other secondary isotopes are also discussed. Spatial and temporal patterns and differences are contrasted. The activity ratios of 131I/137Cs and 134Cs/137Cs measured at several locations are evaluated to gain an insight into the fuel burn-up, the inventory of radionuclides in the reactor and the isotopic signature of the accident. It is important to note that all of the radiation levels detected outside of Japan have been very low and are well below any level of public and environmental hazard. © 2013.


Overweight and obesity in children in Mexico was among the countries with the highest prevalence's in the world. Mexico currently has few innovative and comprehensive experiences to help curb the growth of this serious public health problem. Therefore, the aim of this study is to assess the effectiveness of a nutrition and physical activity strategy, called "Nutrition on the Go" ("nutrición en movimiento") in maintaining the BMI values of school children in the State of Mexico. A two-stage cluster trial was carried out. Sixty schools were selected in the State of Mexico, of which 30 were randomly assigned to the intervention group (IG) and 30 to the control group (CG). A total of 1020 fifth grade school children participated. The intervention strategy aimed to decrease the energy content of school breakfasts and include fruits and vegetables, as well as increase physical activity and the consumption of water during the time spent at school. The strategy was implemented over a 6-month period. The estimated probability (EP) of obesity between baseline and the final stage for the IG decreased 1% (Initial EP = 11.8%, 95%CI 9.0, 15.2, final EP = 10.8, 95%CI 8.4, 13.) For the CG, the probability increased 0.9% (baseline EP = 10.6%; 95%CI 8.1, 13.7; final EP = 11.5, 95%CI 9.0, 14.6). The interaction between the intervention and the stage is the average odd time corrected treatment effect, which is statistically significant (p = 0.01) (OR = 0.68, 95%CI 0.52, 091).This represents the interaction between intervention and stage, which is highly significant (p = 0.01) (OR = 0.68; 95%CI 0.52, 091). In addition, girls had a protective effect on obesity (OR = 0.56; 95%CI 0.39, 0.80). The intervention strategy is effective in maintaining the BMI of school children.


Alparone A.,Center for Monitoring Research | Librando V.,Center for Monitoring Research | Librando V.,University of Catania
Chemosphere | Year: 2013

This paper expands upon our original work on nitroanthracenes in (Alparone, A., Librando, V., 2012. Spectrochim. Acta A 89, 129-136) on the series of nitrophenanthrene isomers. Geometries, electric properties, IR and Raman spectra of 1-, 2-, 3-, 4- and 9-nitrophenanthrene (1-NP, 2-NP, 3-NP, 4-NP and 9-NP) were obtained and analyzed using Density Functional Theory calculations. The balance between steric and π-conjugative interactions determines the order of stability 4-NP<1-NP∼9-NP<2-NP∼3-NP. IR and Raman spectral zones between 1000 and 1600cm-1 show intense bands noticeably affected by the position of the substituent, being potentially useful to discriminate and monitor the investigated isomers. Dipole moments, summations of IR intensity (ΣIIR) and Raman activity (ΣARaman) over the 3N-6 vibrational modes are sensitive to the structure, increasing steadily from the non-planar to the planar isomers. Good linear relationships between the ΣIIR (r=0.90) and ΣARaman (r=0.99) against the Salmonella typhimurium strain TA98 mutagenic activity of nitrophenanthrenes and isomeric nitroanthracenes are found. On the basis of the structural and vibrational properties, 4-NP seems to have not mutagenic activity, while the unknown TA98 mutagenic potency of 1-nitroanthracene is predicted to be between that of 9-NP and 3-NP. Calculated ΣIIR and ΣARaman values could be used as molecular descriptors for QSARs applications of series of isomers. © 2012 Elsevier Ltd.


Alparone A.,Center for Monitoring Research | Librando V.,University of Catania
Structural Chemistry | Year: 2012

Raman spectra of the dimethylnaphthalene (DMN) isomers (1,2-DMN, 1,3-DMN, 1,4-DMN, 1,5-DMN, 1,6-DMN, 1,7-DMN, 1,8-DMN, 2,3-DMN, 2,6-DMN, 2,7-DMN) were calculated in the gas-phase under the harmonic approximation at the DFT-B3LYP level. The effects of the position of the methyl substituents on the Raman spectra were explored, identifying vibrational markers potentially helpful to discriminate the DMN isomers. The results show that the summation of the Raman activity (ΣA Raman) over the CH 3 stretching vibrations and over all the 3N-6 vibrational modes increase in the order α,α-DMN <α,β-DMN <β,β-DMN. Linear correlations between ΣA Raman values and the experimental first-order biomass-normalized biodegradation rate coefficients were established, revealing the crucial role of inductive and dispersive forces on the biodegradation pathways. ΣA Raman could be a valuable molecular descriptor for QSAR applications. © 2012 Springer Science+Business Media, LLC.


Liudchik A.M.,Center for Monitoring Research
International Journal of Remote Sensing | Year: 2013

A new version of the multi-wave open path optical absorption spectroscopy method is herewith presented for continuous measurements of multiple airborne pollutants along an open light path. It involves a standard least squares procedure that minimizes deviations of the calculated optical thickness of the monitoring path from the measured thickness. A novel feature of the proposed method consists of interpreting the influence of error sources as a discrepancy between sounding spectra, emitting to the reference and working paths, produced by these very errors. It is shown that this discrepancy results in a systematic error in the calculated trace gas concentrations, and its elimination transforms the optical open path meter into an absolute meter.The advantages of the proposed approach are revealed when estimating the role of inaccuracies in signal measurements, wavelength scale lock-in, working wavelength setting, stability of the source of radiation, and inaccuracies in the parameters of the calculating method. The special benefit of the proposed multi-wave optical absorption spectroscopy method lies in using an excess of working wavelengths for reducing the influence of various error sources. © 2013 Copyright Taylor and Francis Group, LLC.

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