scholarly journals Simple methodological approach for assessing microbial mineralization rates in an aqueous anaerobic medium

2021 ◽  
Vol 33 ◽  
Author(s):  
Marcela Bianchessi da Cunha-Santino ◽  
Irineu Bianchini Junior
Keyword(s):  
Water Pressure ◽  
Methodological Approach ◽  
Pressure Gauge ◽  
Reaction Rates ◽  
Emission Rates ◽  
Daily Rate ◽  
Primary Measurement ◽  
Carbon Mass ◽  
Manometric Method ◽  
Organic Resources

Abstract: The aim of this study was to propose and discuss a simple manometric method to quantify the emission rates of gases resulting from the microbial anaerobic mineralization of organic resources, as leaves, thin branches, and macrophyte detritus. The proposed method can be used under laboratory conditions. The method consists of using a water pressure gauge attached to the reaction flask. The incubations were prepared with samples of water from Paranapanema River and Typha domingensis, the experiment lasted 9.8 months. The procedures for preparing the incubations are presented in detail, as well as the calculations for the conversion of the volumetric measurement into carbon mass (i.e., daily rate of carbon gas emissions). According to the results obtained from T. domingensis mineralization assays it was possible to demonstrate that, numerous events related to mineralization could be adequately addressed (e.g., the heterogeneous detritus composition). The results of this method were quite convergent with those obtained in kinetic experiments (used as a reference) after the 30th mineralization day, suggesting the use of this method mainly for medium- and long-term experiments. As exemplified by T. domingensis incubations, this method is particularly valuable for the systemic comparison of the several organic resources mineralization and for the primary measurement of the main parameters involved (e.g., reaction rates constants). This method combined with other short-term experiments can greatly improve the understanding of the cycling of organic resources in aquatic environments.

scholarly journals Technical Note: Using wavelet analyses on water depth time series to detect glacial influence in high-mountain hydrosystems

2013 ◽  
Vol 10 (4) ◽  
pp. 4369-4395 ◽  
Author(s):  
S. Cauvy-Fraunié ◽  
T. Condom ◽  
A. Rabatel ◽  
M. Villacis ◽  
D. Jacobsen ◽  
...  
Keyword(s):  
Time Series ◽  
Water Depth ◽  
Water Pressure ◽  
Methodological Approach ◽  
Technical Note ◽  
High Mountain ◽  
Tropical Andes ◽  
Glacial Meltwater ◽  
Depth Measurement ◽  
Wavelet Analyses

Abstract. Worldwide, the rapid shrinking of glaciers in response to ongoing climate change is currently modifying the glacial meltwater contribution to hydrosystems in glacierized catchments. Assessing the contribution of glacier run-off to stream discharge is therefore of critical importance to evaluate potential impact of glacier retreat on water quality and aquatic biota. This task has challenged both glacier hydrologists and ecologists over the last 20 yr due to both structural and functional complexity of the glacier-stream system interface. Here we propose a new methodological approach based on wavelet analyses on water depth time series to determine the glacial influence in glacierized catchments. We performed water depth measurement using water pressure loggers over ten months in 15 stream sites in two glacier-fed catchments in the Ecuadorian Andes (> 4000 m). We determined the global wavelet spectrum of each time series and defined the Wavelet Glacier Signal (WGS) as the ratio between the global wavelet power spectrum value at a 24 h-scale and its corresponding significance value. To test the relevance of the WGS we compared it with the percentage of the glacier cover in the catchments, a metric of glacier influence often used in the literature. We then tested whether one month data could be sufficient to reliably determine the glacial influence. As expected we found that the WGS of glacier-fed streams decreased downstream with the increasing of non-glacial tributaries. We also found that the WGS and the percentage of the glacier cover in the catchment were significantly positively correlated and that one month data was sufficient to identify and compare the glacial influence between two sites, provided that the water level time series were acquired over the same period. Furthermore, we found that our method permits to detect glacial signal in supposedly non-glacial sites, thereby evidencing glacial meltwater infiltrations. While we specifically focused on the tropical Andes in this paper, our approach to determine glacier influence would be applicable to temperate and arctic glacierized catchments. The WGS therefore appears as a powerful and cost effective tool to better understand the hydrological links between glaciers and hydrosystems and assess the consequences of rapid glacier melting.

Applicability of sniffing team observations: experience of field measurements

2001 ◽  
Vol 44 (9) ◽  
pp. 65-70 ◽  
Author(s):  
H. Van Langenhove ◽  
G. Van Broeck
Keyword(s):  
Methodological Approach ◽  
Atmospheric Dispersion ◽  
Atmospheric Model ◽  
Emission Rates ◽  
Dispersion Models ◽  
Short Term ◽  
Dispersion Parameters ◽  
Standard Deviations ◽  
The Impact ◽  
Odour Perception

Sniffing measurement campaigns are a commonly used technique in Flanders to estimate the impact of an odour emission source. The Department of Organic Chemistry at Ghent University has developed its own sniffing strategy throughout the last ten years. The method uses, in essence, the technique of plotting odour perception areas and calculation of total odour emission rates based on maximum odour perception distance. 566 sniffing measurements, executed from 1990 until 1999 around industrial and agricultural odour sources were collected in a database for statistical analysis. Short-term dispersion modelling was executed using four different models, two of them based on Bultynck-Malet dispersion parameters, and two based on Pasquill dispersion parameters. Results from this analysis demonstrate some causes of variance in calculated emissions and show the fitness of each model. From the results of the sniffing teams, which are expressed as sniffing units (SU) instead of odour units (OU, OUE) to underline the difference in methodological approach, the overall odorous emission can be calculated, using short-term atmospheric dispersion models. In a second step, long-term dispersion models can be used to calculate isopercentile contour plots. According to our experience the short-term atmospheric model is a source of “noise” in the method since calculated standard deviations on calculated emissions are larger than standard deviations in the observed maximum distance for odour perception. This will be illustrated by presenting results from the evaluation of composting plants and animal farm houses.

scholarly journals DESIGN OF PRESSURE MEASUREMENT IN THE EXERCISE SMART MINE USING A PRESSURE SENSOR

JOURNAL ASRO ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 166
Author(s):  
Endin Tri Hartanto ◽  
Edy Widodo ◽  
Ayip Rivai Prabowo ◽  
Sulaiman Sulaiman
Keyword(s):  
Pressure Sensor ◽  
Pressure Measurement ◽  
Water Waves ◽  
Water Pressure ◽  
Pressure Gauge ◽  
Air Pressure ◽  
Voltage Output ◽  
Pressure Variable ◽  
Analog Voltage ◽  
Voltage Conversion

The Sea Mines are explosive devices placed in the waters to destroy ships or submarines. The sea mines were placed in the water depths and waited until it was triggered to be blown up by an approaching enemy vessel. The waves in the leave can be measured using the air pressure sensor placed below the water surface, the change in the sensor up and down will result in changes in air pressure. Changes in the resulting pressure of the vessel will result in water waves, resulting from changes in the water wave height will result in a change in water pressure gauge sensors in the air. The MPX5700 air pressure Sensor, as a source of pressure measurement with analog voltage output is comparable to the large value of air pressure. Design the air pressure measuring instrument system using the Arduino microcontroller as the unit of the voltage conversion process to the pressure variable in the KPA. On testing authors use applications that are created using Visual Studio 2012 to plotting the pressure graphs and large voltage output sensors. Results obtained using the MPX5700 sensor with an analog output can result in a linear pressure output with a large voltage output, from the test result obtained the conversion value 0.2 V as the value of 0 Kpa and the value of 4.7 V asthe maximum value pressure measurement of 700 Kpa. Keywords: mines, MPX5700, Arduino microcontrollers

scholarly journals Analytical Results Connecting Stellar Structure Parameters and Extended Reaction Rates

2014 ◽  
Vol 2014 ◽  
pp. 1-12
Author(s):  
Hans J. Haubold ◽  
Dilip Kumar
Keyword(s):  
Energy Distribution ◽  
Reaction Rate ◽  
Special Functions ◽  
Boltzmann Distribution ◽  
Reaction Rates ◽  
Neutrino Emission ◽  
Stellar Structure ◽  
General Distribution ◽  
Emission Rates ◽  
New Energy

Possible modification in the velocity distribution in the nonresonant reaction rates leads to an extended reaction rate probability integral. The closed form representation for these thermonuclear functions is used to obtain the stellar luminosity and neutrino emission rates. The composite parameter 𝒞 that determines the standard nuclear reaction rate through the Maxwell-Boltzmann energy distribution is extended to 𝒞* by the extended reaction rates through a more general distribution than the Maxwell-Boltzmann distribution. The new distribution is obtained by the pathway model introduced by Mathai (2005). Simple analytic models considered by various authors are utilized for evaluating stellar luminosity and neutrino emission rates and are obtained in generalized special functions such as Meijer's G-function and Fox's H-function. The standard and extended nonresonant thermonuclear functions are compared by plotting them. Behaviour of the new energy distribution, which is more general than the Maxwell-Boltzmann, is also studied.

A Microcombustion Method To Measure Forest Fuel Emissions

1984 ◽  
Vol 2 (4) ◽  
pp. 260-275 ◽  
Author(s):  
Hubert B. Clements ◽  
Charles A. McMahon
Keyword(s):  
Evolved Gas Analysis ◽  
Gas Analysis ◽  
Emission Rates ◽  
Evolved Gas ◽  
Volatile Organic Carbon ◽  
Volatile Organic ◽  
Forest Fuel ◽  
Carbon Mass Balance ◽  
Carbon Mass ◽  
Total Hydrocarbons

Thermogravimetry (TG) was applied to forest fuel as a microcombustion tech nique to study emissions by evolved gas analysis (EGA). Emission rates for car bon monoxide (CO), carbon dioxide (CO2), and total hydrocarbons (THC) for both combustion and pyrolysis processes were determined. Thermoparticulates (TP) were emitted in copious amounts; TP emission factors were 85 g/kg and 249 g/kg for the combustion and pyrolytic conditions, respectively, while factors for volatile organic carbon (VOC) compounds collected in plugs of polyurethane foam (PUFS) were the same (~ 66 g/kg) for both conditions. A carbon mass balance on two series of the tests accounted for 95 percent of the fuel carbon content.

Inferring middle-atmospheric ozone height profiles from ground-based measurements of molecular oxygen emission rates, I: Model description and sensitivity to inputs

1991 ◽  
Vol 69 (8-9) ◽  
pp. 1069-1075 ◽  
Author(s):  
R. J. Sica
Keyword(s):  
High Resolution ◽  
Density Profile ◽  
Emission Rate ◽  
Middle Atmosphere ◽  
Reaction Rates ◽  
Model Description ◽  
Atmospheric Ozone ◽  
Emission Rates ◽  
Absolute Value ◽  
Better Than

Improvements in the sensitivity and automation of high-resolution, ground-based spectrometers and interferometers allow the routine acquisition of measurements not only in the nightglow, but in the twilight. Measurements of the emission rate of the O2(1Δg) and O2(1Σg) bands have been used, primarily in the dayglow, to infer mesospheric O3 profiles. This paper describes a model for the inversion of twilight O2(1Δg) and O2(1Σg) emission-rate measurements to obtain O3 height profiles, concentrating on the sensitivity of the results to temperature profile, solar flux, photodissociations rates, uncertainties in the reaction rates, and constants, and the importance of transfer chemistry as a contribution to the O2(1Δg) emission rate, using a fixed O3 profile. The sensitivity of the calculations to inputs other than the desired O3 density shows this method may not be suitable for the absolute value of the O3 density (to better than about 25%), but can successfully determine the shape of the O3-density profile in the middle atmosphere.

scholarly journals Simulations of Sulfate-Nitrate-Ammonium (SNA) aerosols during the extreme haze events over Northern China in October 2014

2016 ◽  
Author(s):  
Dan Chen ◽  
Zhiquan Liu ◽  
Jerome Fast ◽  
Junmei Ban
Keyword(s):  
Relative Humidity ◽  
Observational Data ◽  
Heterogeneous Reaction ◽  
Northern China ◽  
Reaction Rates ◽  
Heterogeneous Reactions ◽  
Formation Mechanisms ◽  
Emission Rates ◽  
Oxidation Rates ◽  
The North

Abstract. Extreme haze events have occurred frequently over China in recent years. Although many studies have investigated the formation mechanisms associated with PM2.5 for heavily polluted regions in China based on observational data, adequately predicting peak PM2.5 concentrations is still challenging for regional air quality models. In this study, we evaluate the performance of one configuration of the Weather Research and Forecasting model coupled with chemistry (WRF-Chem) and use the model to investigate the sensitivity of heterogeneous reactions on simulated peak sulfate, nitrate, and ammonium concentrations in the vicinity of Beijing during four extreme haze episodes in October 2014 over the North China Plain. The highest observed PM2.5 concentration of 469 μg m-3 occurred in Beijing. Comparisons with observations show that the model reproduced the temporal variability in PM2.5 with the highest PM2.5 values on polluted days (defined as days in which observed PM2.5 is greater than 75 μg m-3), but predictions of sulfate, nitrate, and ammonium were too low on days with the highest observed concentrations. Observational data indicate that the sulfur/nitric oxidation rates are strongly correlated with relative humidity during periods of peak PM2.5; however, the model failed to reproduce the highest PM2.5 concentrations due to missing heterogeneous reactions. As the parameterizations of those reactions is not well established yet, estimates of SO2-to-H2SO4 and NO2/NO3-to-HNO3 reaction rates that depend on relative humidity were applied which improved the simulation of sulfate, nitrate, and ammonium enhancement on polluted days in terms of both concentrations and partitioning among those species. Sensitivity simulations showed that the extremely high heterogeneous reaction rates and also higher emission rates than those reported in the emission inventory were likely important factors contributing to those peak PM2.5 simulations.

scholarly journals Basal interstitial water pressure in laboratory debris flows over a rigid bed in an open channel

2012 ◽  
Vol 12 (8) ◽  
pp. 2499-2505 ◽  
Author(s):  
N. Hotta
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Interstitial Water ◽  
Water Pressure ◽  
Pressure Gauge ◽  
Sediment Concentration ◽  
High Temporal Resolution ◽  
Essential Information ◽  
Linear Behavior ◽  
Before And After

Abstract. Measuring the interstitial water pressure of debris flows under various conditions gives essential information on the flow stress structure. This study measured the basal interstitial water pressure during debris flow routing experiments in a laboratory flume. Because a sensitive pressure gauge is required to measure the interstitial water pressure in shallow laboratory debris flows, a differential gas pressure gauge with an attached diaphragm was used. Although this system required calibration before and after each experiment, it showed a linear behavior and a sufficiently high temporal resolution for measuring the interstitial water pressure of debris flows. The values of the interstitial water pressure were low. However, an excess of pressure beyond the hydrostatic pressure was observed with increasing sediment particle size. The measured excess pressure corresponded to the theoretical excess interstitial water pressure, derived as a Reynolds stress in the interstitial water of boulder debris flows. Turbulence was thought to induce a strong shear in the interstitial space of sediment particles. The interstitial water pressure in boulder debris flows should be affected by the fine sediment concentration and the phase transition from laminar to turbulent debris flow; this should be the subject of future studies.

scholarly journals Development of a Reduced Order Model for Fuel Burnup Analysis

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 890 ◽  
Author(s):  
Christian Castagna ◽  
Manuele Aufiero ◽  
Stefano Lorenzi ◽  
Guglielmo Lomonaco ◽  
Antonio Cammi
Keyword(s):  
Methodological Approach ◽  
Computational Cost ◽  
Reaction Rates ◽  
Reduced Order Model ◽  
Fuel Burnup ◽  
Order Model ◽  
Reduced Order ◽  
Solution Accuracy ◽  
Proper Orthogonal ◽  
Over Time

Fuel burnup analysis requires a high computational cost for full core calculations, due to the amount of the information processed for the total reaction rates in many burnup regions. Indeed, they reach the order of millions or more by a subdivision into radial and axial regions in a pin-by-pin description. In addition, if multi-physics approaches are adopted to consider the effects of temperature and density fields on fuel consumption, the computational load grows further. In this way, the need to find a compromise between computational cost and solution accuracy is a crucial issue in burnup analysis. To overcome this problem, the present work aims to develop a methodological approach to implement a Reduced Order Model (ROM), based on Proper Orthogonal Decomposition (POD), in fuel burnup analysis. We verify the approach on 4 years of burnup of the TMI-1 unit cell benchmark, by reconstructing fuel materials and burnup matrices over time with different levels of approximation. The results show that the modeling approach is able to reproduce reactivity and nuclide densities over time, where the accuracy increases with the number of basis functions employed.

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