Measuring and simulating pH buffer capacity of calcareous soils using empirical and mechanistic models

2019 ◽  
Vol 66 (4) ◽  
pp. 559-571
Author(s):  
Mohsen Jalali ◽  
Arefeh Moradi
Keyword(s):  
Buffer Capacity ◽  
Calcareous Soils ◽  
Mechanistic Models ◽  
Ph Buffer ◽  
Empirical And Mechanistic Models

Effect of induced metabolic acidosis on intracellular pH, buffer capacity and contraction force of human skeletal muscle

1985 ◽  
Vol 69 (5) ◽  
pp. 505-510 ◽  
Author(s):  
E. Hultman ◽  
S. Del Canale ◽  
H. Sjöholm
Keyword(s):  
Buffer Capacity ◽  
Recovery Period ◽  
Mean Values ◽  
Muscle Ph ◽  
Before And After ◽  
Ph Buffer ◽  
Total Capacity ◽  
Ph Decrease ◽  
Muscle Biopsies

1. Five volunteers were studied before and after oral administration of NH4Cl (0.3 g/kg body wt.) given in order to create a moderate acidosis. 2. The quadriceps femoris muscles were stimulated electrically for 75 s and muscle biopsies for determination of pH and metabolite content were taken before, at the end of contraction and after 10 min in the recovery period. 3. Muscle pH at rest (mean 7.04) was not significantly decreased after acidification despite an extracellular pH decrease of 0.15 unit. 4. After contraction muscle pH was significantly lower after NH4Cl. Mean values before and after acidification were 6.70 and 6.54 respectively. 5. The buffer capacity calculated as the total capacity of the muscle to buffer H+ produced during the isometric contraction before and after NH4Cl ingestion was reduced from 68.6 sl to 54.5 sl. 6. The force produced by contracting muscle was significantly lower at the end of the contraction period after NH4Cl ingestion, 44.6% of initial compared with 55.4% without NH4Cl.

Analysis of Ammonia Volatilization Loss from a Paddy Soil With Empirical and Mechanistic Models

2021 ◽  
pp. 2000230
Author(s):  
Wen‐Ming Xie ◽  
Pei‐Kun Yuan ◽  
You Ma ◽  
Wei‐Ming Shi ◽  
Hai‐Lin Zhang ◽  
...  
Keyword(s):  
Paddy Soil ◽  
Ammonia Volatilization ◽  
Mechanistic Models ◽  
Empirical And Mechanistic Models

Estimation of enteric methane emissions trends (1990–2008) from Manitoba beef cattle using empirical and mechanistic models

2011 ◽  
Vol 91 (2) ◽  
pp. 305-321 ◽  
Author(s):  
Aklilu Alemu ◽  
K. H. Ominski ◽  
E. Kebreab
Keyword(s):  
Beef Cattle ◽  
Methane Emissions ◽  
Mechanistic Models ◽  
Tier 2 ◽  
Cattle Population ◽  
Production Environment ◽  
Feed Composition ◽  
Enteric Methane ◽  
Empirical And Mechanistic Models ◽  
Enteric Methane Emissions

Alemu, A. W., Ominski, K. H. and Kebreab, E. 2011. Estimation of enteric methane emissions trends (1990–2008) from Manitoba beef cattle using empirical and mechanistic models. Can. J. Anim. Sci. 91: 305–321. The objective of this study was to estimate and assess trends in enteric methane (CH4) emissions from the Manitoba beef cattle population from the base year of 1990 to 2008 using mathematical models. Two empirical (statistical) models: Intergovernmental Panel on Climate Change (IPCC) Tier 2 and a nonlinear equation (Ellis), and two dynamic mechanistic models: MOLLY (v3) and COWPOLL were used. Beef cattle in Manitoba were categorized in to 29 distinct subcategories based on management practice, physiological status, gender, age and production environment. Data on animal performance, feeding and management practices and feed composition were collected from the literature as well as from provincial and national sources. Estimates of total enteric CH4 production from the Manitoba beef cattle population varied between 0.9 and 2.4 Mt CO2 eq. from 1990 to 2008. Regardless of the type of models used, average CH4 emissions for 2008 were estimated to be 45.2% higher than 1990 levels. More specifically, CH4 emissions tended to increase between 1990 and 1996. Emissions were relatively stable between 1996 and 2002, increased between 2003 and 2005, but declined by 13.2% between 2005 and 2008, following the same trend as that observed in the beef cattle population. Models varied in their estimates of CH4 conversion rate (Ym, percent gross energy intake), emission factor (kg CH4 head−1 yr−1) and CH4 production. Total CH4 production estimates ranged from 1.2 to 2.0 Mt CO2 eq. for IPCC Tier 2, from 0.9 to 1.5 Mt CO2 eq. for Ellis, from 1.3 to 2.1 Mt CO2 eq. for COWPOLL and from 1.5 to 2.4 Mt CO2 eq. for MOLLY. The results indicate that enteric CH4 estimates and emission trends in Manitoba were influenced by the type of model and beef cattle population. As such, it is necessary to use appropriate models for reliable estimates for enteric CH4 inventory. A more robust approach may be to integrate different models by using mechanistic models to estimate regional Ym values, which may then be used as input for the IPCC Tier 2 model.

Relationships between extractable Al, selected soil properties, pH buffer capacity and lime requirement in some acidic Queensland soils

Soil Research ◽  
1992 ◽  
Vol 30 (2) ◽  
pp. 119 ◽  
Author(s):  
RL Aitken
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Soil Properties ◽  
Buffer Capacity ◽  
Clay Content ◽  
Ph Buffering ◽  
Ph Buffer ◽  
Mineral Soils ◽  
Chloride Salts ◽  
Hydrolysis Of

The objectives of this study were to examine (1) interrelationships between various forms of extractable A1 and selected soil properties, (2) the contribution of extractable A1 to pH buffer capacity, and (3) investigate the use of extractable A1 to predict lime requirement. Aluminium was extracted from each of 60 Queensland soils with a range of chloride salts: 1 M KCl (AlK), 0.5 M CuCl2 (AlCu), 0.33 M LaCl3 (AlLa) and 0.01 M CaCl2 (AlCa). The amounts of A1 extracted were in the order AlCu > AlLa > Alk > AlCa. Little or no A1 was extracted by KC1 or Lac13 in soils with pHw values greater than 5.5 , whereas CuCl2 extracted some A1 irrespective of soil pH. The greater amounts of A1 extracted by CuCl2 were attributed mainly to A1 from organic matter, even though all of the soils were mineral soils (organic carbon 54.7%). Both AlCu and AlLa, were significantly (P < 0.001) correlated with organic carbon, whereas none of the extractable A1 measures was correlated with clay content. AlK and A~L, were poorly correlated to pH buffer capacity. The linear relationship between AlCu and pH buffer capacity (r2 = 0.49) obtained in this study supports the view of previous researchers that the hydrolysis of A1 adsorbed by organic matter is a source of pH buffering in soils. However, the change in CEC with pH accounted for 76% of the variation in pH buffer capacity, indicating that other mechanisms such as deprotonation of organic groups and variable charge minerals are also involved in pH buffering. The ability of CuCl2 and LaCl3extractable Al to estimate lime requirement depended on the target pH. The results suggest that lime requirements based on neutralization of AlLa would be sufficient to raise pHw to around 5.5, whereas requirements based on neutralization of AlCu substantially overestimated the actual lime requirement to pHw 5.5, but gave a reasonable estimation of the lime requirement to pHw 6 5.

The Buffer Capacity of Calcareous Soils in Gansu Province of China

1997 ◽  
Vol 13 (4) ◽  
pp. 213-222 ◽  
Author(s):  
Chu Taiwei ◽  
Du Jinzhou ◽  
Song Yongjie ◽  
Tao Zuyi
Keyword(s):  
Buffer Capacity ◽  
Calcareous Soils ◽  
Gansu Province

The effect of valence and Ionic-strength on the measurement of pH buffer capacity

Soil Research ◽  
1994 ◽  
Vol 32 (5) ◽  
pp. 975 ◽  
Author(s):  
RL Aitken ◽  
PW Moody
Keyword(s):  
Ionic Strength ◽  
Titration Curve ◽  
Buffer Capacity ◽  
Experimental Conditions ◽  
Linear Portion ◽  
Titration Curves ◽  
Addition Rate ◽  
Ph Buffer ◽  
Buffer Capacities ◽  
Linear Regressions

Although the measurement of pH buffer capacity (pHBC) is used to determine lime requirement and acid addition rate in acidification studies, the experimental conditions under which pHBC is determined have not been studied. The effect of valence and ionic strength on the measurement of pHBC was investigated on a range of soils. The effect of the monovalent or divalent accompanying ion was examined by establishing separate titration curves for each of 100 soils by adding incremental amounts of either Ca(OH)2, NaOH, HCl or H2SO4 to soil suspended (1 : 5) in water. Linear regressions were fitted to the linear portion of each titration curve and the slopes of these lines were used as a measure of pHBC. For each soil, the pH buffer capacities were statistically compared. The pHBC determined with Ca(OH)2 was significantly (P = 0.05) greater than that determined with NaOH in 92 soils and, on average (all soils), was 2.2 times the pHBC in NaOH. The effect of ionic strength on pHBC was investigated in each of 20 soils by titrating with HCI in water and suspensions at nominal ionic strengths of 0.006, 0.03 and 0.3 m. In all soils there was a trend for increasing pHBC with increasing ionic strength (I) and, for I < 0.03 m, there was a marked increase in pHBC with increasing I. The results are discussed in relation to the effect of valence and ionic strength on pH buffer capacity mechanisms, and the implications with respect to calculating acidification rates and lime requirements.

pH Buffer Capacity Based Monitoring of Algal Wastewater Treatment

1999 ◽  
Vol 20 (6) ◽  
pp. 547-561 ◽  
Author(s):  
L. Van Vooren ◽  
P. Lessard ◽  
J.-P. Ottoy ◽  
P. A. Vanrolleghem
Keyword(s):  
Wastewater Treatment ◽  
Buffer Capacity ◽  
Ph Buffer

scholarly journals Comparative analysis of biophysical parameters of oral fluid depending on the condition of dental hard tissue

2019 ◽  
Vol 84 (3) ◽  
pp. 23-29
Author(s):  
S.P. Yarova ◽  
I.I. Zabolotna ◽  
V.V. Petukhov ◽  
О.A. Kobtseva ◽  
O.P. Reva
Keyword(s):  
Oral Fluid ◽  
Buffer Capacity ◽  
Preventive Measures ◽  
Dispersion Coefficient ◽  
Liquid Crystal Phase ◽  
Hard Tissue ◽  
Biophysical Parameters ◽  
Dispersion Coefficients ◽  
Ph Buffer ◽  
High Degree

The pH, buffer capacity, salivation rate, impedance, micellarity and mineralizing ability of the oral fluid have been determined by the indices of the dispersion coefficient. The dispersion coefficients impedance of oral fluid in patients with a wedge-shaped defect and precervical caries were significantly lower than in patients with intact hard tissues (p=0,004). The greatest steepness of dispersion coefficient was typical for the oral fluid of individuals without any precervical pathology, which corresponds to a high degree of its liquid crystal phase, greater dispersion and micellarity. The strong indirect correlation between impedance and pH and buffer capacity has been revealed and the vivid direct correlation with salivation rate and dispersion coefficient has been found. The interconnections between biophysical parameters of oral fluid require further research in order to diagnose precervical pathology and monitor the effectiveness of preventive measures.

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