Removal of trace metals from the oceans: a zero order model

1977 ◽  
Vol 24 (4) ◽  
pp. 297
Keyword(s):  
Trace Metals ◽  
Zero Order ◽  
Order Model

A new model of resorbable device degradation and drug release - part I: zero order model

2008 ◽  
Vol 57 (7) ◽  
pp. 912-920 ◽  
Author(s):  
Paolo Arosio ◽  
Valentina Busini ◽  
Giuseppe Perale ◽  
Davide Moscatelli ◽  
Maurizio Masi
Keyword(s):  
Drug Release ◽  
Zero Order ◽  
Order Model ◽  
New Model

Simplified estimation of forage degradability in the rumen assuming zero-order degradation kinetics

2008 ◽  
Vol 147 (3) ◽  
pp. 225-240 ◽  
Author(s):  
M. S. DHANOA ◽  
S. LÓPEZ ◽  
R. SANDERSON ◽  
J. FRANCE
Keyword(s):  
Reference Values ◽  
Incubation Time ◽  
Lag Time ◽  
Zero Order ◽  
Regression Equations ◽  
Order Model ◽  
First Order ◽  
Simplified Procedure ◽  
The Impact ◽  
Time Point

SUMMARYIn the present paper, a simplified procedure using few in situ data points is derived and then evaluated (using a large database) against reference values estimated with the standard nylon bag first-order kinetics model. The procedure proposed involved a two-stage mathematical process, with a statistical prediction of some degradation parameters (such as lag time) and then a kinetic model derived by assuming degradation follows zero-order kinetics to determine effective degradability in the rumen (E). In addition to the estimation of washout fraction and discrete lag, which is common to both procedures, the simplified procedure requires measurement of dry matter losses at one incubation time point only. Thus, interference of the animal rumen will be much reduced, which will lead to increased capacity for feed evaluation. Calibration of the zero-order model against the first-order model showed that suitable estimates of E can be obtained with disappearance at 24, 48 or 72 h as the single incubation end time point. The strength of the calibration is such that an end incubation time point as low as 24 h may be sufficient, which may reduce substantially the total incubation time required and thus the impact on the experimental animal. Relevant regression equations to predict reference values of parameters such as lag time or E are also developed and validated.

A preliminary study to predict net nitrogen mineralisation in a flooded rice soil using anaerobic incubation

1994 ◽  
Vol 34 (7) ◽  
pp. 995 ◽  
Author(s):  
JF Angus ◽  
M Ohnishi ◽  
T Horie ◽  
RL Williams
Keyword(s):  
N Uptake ◽  
Order Reaction ◽  
Zero Order ◽  
Organic N ◽  
N Mineralisation ◽  
Anaerobic Incubation ◽  
Flooded Soil ◽  
Order Model ◽  
First Order ◽  
Net Mineralisation

Complementary field and laboratory studies were conducted to determine whether laboratory measurements of net nitrogen (N) mineralisation under anaerobic conditions could be used to predict field rates in a flooded soil and N uptake by a rice crop. The laboratory experiment consisted of measurements of ammonium accumulation at 10, 20, 30, and 40�C for 7, 14, and 28 days of anaerobic incubation. There was no accumulation of ammonium at 10�C, but increasing ammonification rate at temperatures of 20�C was observed, except for a slower rate at 40�C after 14 days. Two models were tested on the data: a zero-order reaction in which rate of mineralisation was a linear function of temperature; a first-order reaction in which net N mineralisation rate was a proportion of a depleting pool of labile organic N. In the second model, the rate was also linearly related to temperature. Both models fitted the laboratory data well (R2 = 0.94 and 0.97, respectively), but the second model accounted better for mineralisation at 40�C for the 28-day incubation. These models were then run, using daily mean temperatures over a rice-growing season, to predict net mineralisation in the field. The predictions were compared with measured net N mineralisation in a flooded soil and N uptake by the crop measured throughout the season in the field from which the incubated soil was sampled. Net N mineralisation and crop uptake increased throughout the season, reaching maximum values of 115 and 111 kg N/ha at maturity. The zero-order and first-order models both predicted net N mineralisation accurately until the middle of the season, after which the zero-order model overestimated net N mineralisation but the first-order model predicted the reduction in the rate of net N mineralisation with reasonable accuracy. The close agreement between the laboratory incubations and field measurements of net mineralisation and crop N uptake suggest that incubation tests may provide useful information for including in a model to assist rice growers' decisions about N fertiliser.

scholarly journals Short-term forecast of fire in the premises based on modification of the Brown’s zero-order model

2021 ◽  
Vol 4 (10(112)) ◽  
pp. 52-58
Author(s):  
Boris Pospelov ◽  
Evgenіy Rybka ◽  
Olekcii Krainiukov ◽  
Oleksandr Yashchenko ◽  
Yuliia Bezuhla ◽  
...  
Keyword(s):  
Time Series ◽  
A Priori ◽  
Absolute Error ◽  
Zero Order ◽  
The State ◽  
Order Model ◽  
Short Term ◽  
Short Term Forecast ◽  
Term Forecast ◽  
Proposed Modification

This paper reports the rationale for the modification of Brown’s zero-order model, which ensures increased accuracy of the short-term fire forecast based on the use of the current measure of recurrence in the increments of the state of the air environment in the premises. A special feature of the proposed model modification is that the a priori model of the dynamics of the level of the time series of the measure of the current recurrence of increments in the air environment states determined by the dangerous factors of the fire has been modified. In this case, it is proposed that the new a priori model should take into consideration additionally the value of the current increments of the level of the studied time series. That makes it possible to negligibly reduce errors of the short-term forecast of fire in the premises without significantly complicating Brown’s zero-order model while retaining all its implementing advantages. The provided accuracy of the forecast for one step in advance on the basis of a time series of measures of the current recurrence of increments of the state of the air environment, determined from the experimental data during the ignition of alcohol and timber in a laboratory chamber, has been investigated. The considered quantitative indicators of forecast accuracy are the absolute and average errors exponentially smoothed with a parameter of 0.4. It has been established that for the proposed modification the value of the average absolute error does not exceed 0.02 %. That means that an error of the short-term forecast of a fire in the premises based on the proposed modification is an order of magnitude less than that in the case of using known Brown’s model at the smoothing parameter from an unclustered set. The results from the ignition of alcohol and timber in the laboratory chamber, in general, indicate significant advantages of using the proposed modification of Brown’s zero-order model for a short-term forecast of a fire in the premises.

scholarly journals Evaluation of Plantago major L. seed mucilage as a rate controlling matrix for sustained release of propranolol hydrochloride

2013 ◽  
Vol 63 (1) ◽  
pp. 99-114 ◽  
Author(s):  
Majid Saeedi ◽  
Katayoun Morteza-Semnani ◽  
Mehdi Sagheb-Doust
Keyword(s):  
Zero Order ◽  
Plantago Major ◽  
Propranolol Hydrochloride ◽  
Order Model ◽  
Ir Studies ◽  
No Formation ◽  
Lower Drug ◽  
Ft Ir ◽  
Seed Mucilage ◽  
Polymer Ratio

Polysaccharide mucilage derived from the seeds of Plantago major L. (family Plantaginaceae) was investigated for use in matrix formulations containing propranolol hydrochloride. HPMC K4M and tragacanth were used as standards for comparison. The hardness, tensile strength, and friability of tablets increased as the concentration of mucilage increased, indicating good compactibility of mucilage powders. The rate of release of propranolol hydrochloride from P. major mucilage matrices was mainly controlled by the drug/mucilage ratio. Formulations containing P. major mucilage were found to exhibit a release rate comparable to HPMC containing matrices at a lower drug/polymer ratio (drug/HPMC 2:1). These results demonstrated that P. major mucilage is a better release retardant compared to tragacanth at an equivalent content. The results of kinetic analysis showed that in F3 (containing 1:2 drug/mucilage) the highest correlation coefficient was achieved with the zero order model. The swelling and erosion studies revealed that as the proportion of mucilage in tablets was increased, there was a corresponding increase in percent swelling and a decrease in percent erosion of tablets. The DSC and FT-IR studies showed that no formation of complex between the drug and mucilage or changes in crystallinity of the drug had occurred.

scholarly journals Sample Size Requirements for Zero-Order Models

1980 ◽  
Vol 17 (2) ◽  
pp. 221-227 ◽  
Author(s):  
Manohar U. Kalwani ◽  
Donald G. Morrison
Keyword(s):  
Parameter Estimation ◽  
Maximum Likelihood ◽  
Sample Size ◽  
Market Share ◽  
Zero Order ◽  
Maximum Likelihood Estimates ◽  
Model Estimation ◽  
Order Model ◽  
Model Parameter ◽  
Polarization Index

The authors report the sample sizes required to obtain maximum likelihood estimates of parameters in a zero-order model. In the typical formulation of the model, parameter estimation requires about 2000 individuals with five purchases per consumer. The original parameters can be easily transformed, however, into a market share estimate and a polarization index that convey the key information sought from the model. Estimation of the transformed parameters requires smaller samples of about 400 individuals with five purchases per consumer.

The ?Zero-order Model? revisited: Paul Schindler's influence on the development of trace metal scavenging models

1993 ◽  
Vol 55 (4) ◽  
pp. 230-239 ◽  
Author(s):  
Peter H. Santschi ◽  
Bruce D. Honeyman ◽  
Matthew S. Quigley
Keyword(s):  
Trace Metal ◽  
Zero Order ◽  
Order Model
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