Determination of methane yield in cattle fed tropical grasses as measured in open-circuit respiration chambers

2018 ◽  
Vol 258 ◽  
pp. 3-7 ◽  
Author(s):  
Juan Carlos Ku-Vera ◽  
Sara S. Valencia-Salazar ◽  
Angel T. Piñeiro-Vázquez ◽  
Isabel C. Molina-Botero ◽  
Julián Arroyave-Jaramillo ◽  
...  
Keyword(s):  
Open Circuit ◽  
Methane Yield ◽  
Tropical Grasses

Determination of methane yield of cellulose using different experimental setups

2014 ◽  
Vol 70 (4) ◽  
pp. 599-604 ◽  
Author(s):  
Bing Wang ◽  
Ivo Achu Nges ◽  
Mihaela Nistor ◽  
Jing Liu
Keyword(s):  
Water Column ◽  
Test System ◽  
Methane Yield ◽  
Biochemical Methane Potential ◽  
Methane Potential ◽  
Bmp Test ◽  
Potential Test

In this work, biochemical methane potential (BMP) tests with cellulose as a model substrate were performed with the aid of three manually operated or conventional experimental setups (based on manometer, water column and gas bag) and one automated apparatus specially designed for analysis of BMP. The methane yields were 340 ± 18, 354 ± 13, 345 ± 15 and 366 ± 5 ml CH4/g VS obtained from experimental setups with manometer, water column, gas bag, and automatic methane potential test system, which corresponded to a biodegradability of 82, 85, 83 and 88% respectively. The results demonstrated that the methane yields of cellulose obtained from conventional and automatic experimental setups were comparable; however, the methane yield obtained from the automated apparatus showed greater precision. Moreover, conventional setups for the BMP test were more time- and labour-intensive compared with the automated apparatus.

Quantitative investigation of polarization-dependent photocurrent in ferroelectric thin films

2021 ◽  
Author(s):  
Komalika Rani ◽  
Sylvia Matzen ◽  
Stéphane Gable ◽  
Thomas Maroutian ◽  
Guillaume Agnus ◽  
...  
Keyword(s):  
Thin Films ◽  
Photovoltaic Effect ◽  
Quantitative Relationship ◽  
Open Circuit ◽  
Ferroelectric Thin Films ◽  
Ferroelectric Polarization ◽  
Ferroelectric Layer ◽  
Ferroelectric Memories ◽  
Careful Investigation

Abstract Ferroelectric thin films are investigated for their potential in photovoltaic (PV) applications, owing to their high open-circuit voltage and switchable photovoltaic effect. The direction of the ferroelectric polarization can control the sign of the photocurrent through the ferroelectric layer, theoretically allowing for 100 percent switchability of the photocurrent with the polarization, which is particularly interesting for photo-ferroelectric memories. However, the quantitative relationship between photocurrent and polarization remains little studied. In this work, a careful investigation of the polarization-dependent photocurrent of epitaxial Pb(Zr,Ti)O3 thin films has been carried out, and has provided a quantitative determination of the unswitchable part of ferroelectric polarization. These results represent a systematic approach to study and optimize the switchability of photocurrent, and more broadly to get important insights on the ferroelectric behavior in all types of ferroelectric layers in which pinned polarization is difficult to investigate.

Evaluation of Thermodynamic Properties of Cerium in Liquid Cadmium Cathode Within LiCl-KCl Salt System

2016 ◽  
Author(s):  
Dalsung Yoon ◽  
Supathorn Phongikaroon
Keyword(s):  
Thermodynamic Properties ◽  
Gibbs Energy ◽  
Intermetallic Compounds ◽  
Linear Trend ◽  
Open Circuit ◽  
Salt System ◽  
Free Energies ◽  
Enthalpy And Entropy ◽  
Molten Salt System

Thermodynamic properties of Ce-Cd intermetallic compound were investigated in LiCl-KCl-CeCl3-CdCl2 molten salt system at various temperatures. Six Ce-Cd intermetallic compounds, CeCd, CeCd2, CeCd3, Ce13Cd58, CeCd6, and CeCd11 could be observed via cyclic voltammetry (CV) and the relative Gibbs free energies for the intermetallic formations were estimated by the analysis of the anodic peaks in the CV experiments. Furthermore, an open circuit chronopotentiometry which is known as a suitable method for measuring thermodynamic values of intermetallic compounds were performed. The linear trends of the relative Gibbs free energies were found by using potential difference from CV and CP methods. It can be noted that CV method can be easy and fast tool to estimate relative Gibbs energy for intermetallic compounds of Cd-Ms (metals). For the determination of standard Gibbs free energy, enthalpy, and entropy for the intermetallic formation, CP results were used. The linear trend of the Gibbs energy were obtained against temperature changing from 698 K to 823 K. From the linear relationship, the enthalpy and entropy of the formation were calculated.

Absence of persistent methane emission differences in three breeds of dairy cows

2008 ◽  
Vol 48 (2) ◽  
pp. 77 ◽  
Author(s):  
A. Münger ◽  
M. Kreuzer
Keyword(s):  
Dairy Cows ◽  
Analysis Of Variance ◽  
Methane Emission ◽  
Study Data ◽  
Open Circuit ◽  
Minor Importance ◽  
Genetic Determination ◽  
Apparent Lack ◽  
Jersey Cows

In the present study, data from an experiment with 10 purebred Holstein, Simmental and Jersey cows each were analysed to test the assumption that there are genetically low methane-producing animals. Methane emission of cows offered forage ad libitum and some concentrate was measured for 3 days in open-circuit respiration chambers in weeks 8, 15, 23, 33 and 41 of lactation. Individual cow data were analysed in five different ways: (i) plotting the trend of methane per unit of dry matter intake (DMI) and milk yield over time; relating measured methane production to estimates derived from equations based on either; (ii) DMI or (iii) nutrient intake; (iv) relating residual feed intake (RFI) to methane emission; and (v) analysis of variance of cow × measurement interactions. The Holstein, Simmental and Jersey cows emitted on average 25, 25 and 26 g methane/kg DMI, respectively. There was no indication of individual cows with persistently low or high methane yield per kg DMI and per kg milk. Measured methane emissions differed from estimated values without a clear pattern, and the relationship between RFI and methane emission of the cows was weak. Finally, analysis of variance failed to show distinct patterns of methane per unit of DMI and milk for individual animals. The apparent lack of persistence of individual animal differences in methane yields suggests that genetic determination of this trait is of minor importance in dairy cows.

Determination of Electronic Conductance of 100 cm2 Single Molten Carbonate Fuel Cell

2013 ◽  
Vol 346 ◽  
pp. 23-28
Author(s):  
Jarosław Milewski ◽  
Wojciech Bujalski ◽  
Marcin Wołowicz ◽  
Kamil Futyma ◽  
Jan Kucowski ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Open Circuit Voltage ◽  
Open Circuit ◽  
Molten Carbonate Fuel Cell ◽  
Molten Carbonate ◽  
Factors Affecting ◽  
Close Relationship ◽  
Electronic Conductance ◽  
Carbonate Fuel Cell

This work considers electronic conductance in a molten carbonate fuel cell and consequences of its existence. The voltage characteristics of cells show differences between a theoretical maximum circuit voltage and open circuit voltage (OCV). A relationship is assumed between the OCV value and electronic conductance. Based on experimental measurements an appropriate mathematical model was created. The model is used to calculate the temperature dependence of electronic conductance for the most popular types of electrolyte: Li2CO3/K2CO3. The results obtained point to the possible existence of a very close relationship between electronic conductance and open circuit voltage. This relationship enables OCV to be calculated when electronic conductance is known. Appropriate formulae can be determined. Temperature is one of the factors affecting electronic conductance. Other influencing factors do exist, but their impact on OCV is not well known. This article mentions some of them.

Study of a-Si:H / c-Si Heterojunctions for PV Applications

1996 ◽  
Vol 420 ◽  
Author(s):  
F. Zignani ◽  
R. Galloni ◽  
R. Rizzoli ◽  
M. Ruth ◽  
C. Summonte ◽  
...  
Keyword(s):  
Gas Phase ◽  
Open Circuit Voltage ◽  
Accurate Determination ◽  
Electrical Characterization ◽  
Silicon Layer ◽  
Open Circuit ◽  
Hydrogen Dilution ◽  
Intrinsic Efficiency

Abstracta-Si:H / c-Si heterojunction diodes were produced by PECVD with varying amorphous silicon layer thickness and hydrogen dilution of the gas phase. An accurate determination of the growth rate also in the initial stages of the deposition was made possible by an original chemical method based on the dissolution of the films followed by spectroscopical analysis of the obtained solution.The electrical characterization of the diodes confirms the generation - recombination - multitunneling nature of the transport. Although H2 dilution is important, however, beyond a certain level it is detrimental for the junction quality, probably due to the transition to a microcrystalline phase deposition. Solar cells were also produced, the best results being an open circuit voltage of 610 mV and an intrinsic efficiency of 14.2%.

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