Search results for "ANALYZER"

Interaction of metal ions with D-glucobenzothiazoline: isolation and characterization of the resultant products

2002

Six different metal-ion complexes of D-glucobenzothiazoline were synthesized and characterized by analytical and spectral techniques. Formation of different types of species (ML and ML2) were observed with Cu2+, Ag+, Cd2+, Hg2+, and Zn2+ ions. Existence of an anomeric mixture in the case of the Cu2+ complex is identified from the EPR spectra, and the results were further supported by the simulated spectra. The structures were proposed based on different studies.

2012

Abstract. One of the major uncertainties in the understanding of Earth's climate system is the interaction between solar radiation and aerosols in the atmosphere. Aerosols exposed to high humidity will change their chemical, physical, and optical properties due to their increased water content. To model hydrated aerosols, atmospheric chemistry and climate models often use the volume weighted mixing rule to predict the complex refractive index (RI) of aerosols when they interact with high relative humidity, and, in general, assume homogeneous mixing. This study explores the validity of these assumptions. A humidified cavity ring down aerosol spectrometer (CRD-AS) and a tandem hygroscopic DMA…

Nano-hygroscopicity tandem differential mobility analyzer (nano-HTDMA) for investigating hygroscopic properties of sub-10 nm aerosol nanoparticles

2020

Interactions between water and nanoparticles are relevant for atmospheric multiphase processes, physical chemistry, and materials science. Current knowledge of the hygroscopic and related physicochemical properties of nanoparticles, however, is restricted by the limitations of the available measurement techniques. Here, we present the design and performance of a nano-hygroscopicity tandem differential mobility analyzer (nano-HTDMA) apparatus that enables high accuracy and precision in hygroscopic growth measurements of aerosol nanoparticles with diameters less than 10 nm. Detailed methods of calibration and validation are provided. Besides maintaining accurate and stable sheath and a…

Hygroscopic properties and water-soluble volume fraction of atmospheric particles in the diameter range from 50 nm to 3.8 μm during LACE 98

2002

[1] Hygroscopic properties of atmospheric aerosol particles in the Aitken, large, and giant particle range were studied during the Lindenberg Aerosol Characterization Experiment (LACE 98) in a rural area 80 km southeast of Berlin. The hygroscopic behavior of Aitken particles were determined in situ in four size classes (50, 100, 150, 250 nm) with a Hygroscopic Tandem Differential Mobility Analyzer for relative humidities (RH) of 60% and 90%. Measurements at 60% RH served as reference data used by other LACE 98 investigators for mass closure and radiative transfer calculations. In most cases, at 90% RH, the atmospheric particles could be classified into two groups (“more” and “less” hygrosco…

Rates of carbon dioxide plume degassing from Mount Etna volcano,

2006

We report here on the real-time measurement of CO2 and SO2 concentrations in the near-vent volcanic gas plume of Mount Etna, acquired by the use of a field portable gas analyzer during a series of periodic field surveys on the volcano's summit. During the investigated period (September 2004 to September 2005), the plume CO2/SO2 ratio ranged from 1.9 to 10.8, with contrasting composition for Northeast and Voragine crater plumes. Scaling the above CO2/SO2 ratios by UV spectroscopy determined SO2 emission rates, we estimate CO2 emission rates from the volcano in the range 0.9-67.5 kt d-1 (average, 9 kt d-1). About 2 kt of CO2 were emitted daily on average during quiescent passive degassing, wh…

Gas emission strength and evolution of the molar ratio of BrO/SO2in the plume of Nyiragongo in comparison to Etna

2015

Airborne and ground-based differential optical absorption spectroscopy observations have been carried out at the volcano Nyiragongo (Democratic Republic of Congo) to measure SO2 and bromine monoxide (BrO) in the plume in March 2004 and June 2007, respectively. Additionally filter pack and multicomponent gas analyzer system (Multi-GAS) measurements were carried out in June 2007. Our measurements provide valuable information on the chemical composition of the volcanic plume emitted from the lava lake of Nyiragongo. The main interest of this study has been to investigate for the first time the bromine emission flux of Nyiragongo (a rift volcano) and the BrO formation in its volcanic plume. Mea…

Artifacts and Errors in Cross-Spectrum Phase Noise Measurements : Invited lecture

2021

Inserting an attenuator between the oscillator under test and the phase noise analyzer, one expects that the white phase noise increases monotonically with the attenuation. By contrast, we observe that with some oscillators the white noise has sharp minimum for a given value of the attenuation, which clearly indicates problem. With other oscillators, it increases monotonically with the attenuation, but the values are not consistent with the thermal energy introduced by the attenuator. In both cases artifacts are present, which takes the form of a sharp notch in the spectrum, occurring where the white FM noise crosses the white PM noise. Such anomalous behavior is the tip of the iceberg, and…

Adaptive Mid-Term Representations for Robust Audio Event Classification

2018

Low-level audio features are commonly used in many audio analysis tasks, such as audio scene classification or acoustic event detection. Due to the variable length of audio signals, it is a common approach to create fixed-length feature vectors consisting of a set of statistics that summarize the temporal variability of such short-term features. To avoid the loss of temporal information, the audio event can be divided into a set of mid-term segments or texture windows. However, such an approach requires to estimate accurately the onset and offset times of the audio events in order to obtain a robust mid-term statistical description of their temporal evolution. This paper proposes the use of…

Mauna Kea, Hawaii, as an Analog Site for Future Planetary Resource Exploration: Results from the 2010 ILSO-ISRU Field-Testing Campaign

2013

Within the framework of the International Lunar Surface Operation - In-Situ Resource Utilization Analogue Test held on January 27 - February 11, 2010 on the Mauna Kea volcano in Hawaii, a number of scientific instrument teams collaborated to characterize the field site and test instrument capabilities outside laboratory environments. In this paper, we provide a geological setting for this new field-test site, a description of the instruments that were tested during the 2010 ILSO-ISRU field campaign, and a short discussion for each instrument about the validity and use of the results obtained during the test. These results will form a catalogue that may serve as reference for future test cam…

Experimental conditions for respiration and growth studies of F0 and F1 larval and juvenile European seabass Dicentrarchus labrax

2022

Water parameters in the 2 years before spawning of F0 (08.02.2016-06.03.2018) and during larval and juvenile phase of F1: Larval period until 17.05.2018 (48 dph, 900 dd) and 01.06.2018 (63 dph, ~900 dd) for warm and cold life condition respectively, for the juveniles until 28.09.2018 (180 dph, ~4000 dd) and 12.02.2019 (319 dph, ~5100 dd) for warm and cold conditioned fish respectively. Means ± s.e. over all replicate tanks per condition. Temperature (Temp.), pH (free scale), salinity, oxygen and total alkalinity (TA) were measured weekly in F1 and monthly in F0; sea water (SW) measurements were conducted in 2017 and 2018. Water parameters during larval and early juvenile phase of F0: Larval…