Analytical potentiometric data analyses of metal–ligand equilibria by microcomputer. A general procedure for minimizing potential sources of errors and a fast linear-scaled least-squares algorithm

1987 ◽  
Vol 65 (12) ◽  
pp. 2798-2803 ◽  
Author(s):  
Patrick Decock ◽  
Bibudhendra Sarkar
Keyword(s):  
General Procedure ◽  
Formation Constants ◽  
Titration Curves ◽  
Potential Sources ◽  
Free Ion ◽  
Multiple Species ◽  
Preliminary Computation ◽  
Best Fit ◽  
Selection Of ◽  
Potentiometric Data

Analytical potentiometry is a powerful technique to investigate multiple species in solution and their formation constants. However, there have been some difficulties in this method resulting primarily from the theoretical approach. In this paper we critically examined them and improvements have been implemented successfully. Suitable experimental designs are adapted and preliminary computation of potentiometric data are performed to minimize potential sources of errors. Criteria are proposed to choose the best set of titration curves. A correction is introduced to partially minimize the errors originating from the volume variation. A linear-scaled minimization algorithm has been implemented to extract the value of the complex stability constants from the experimental free ion concentrations. This has two advantages over the earlier non-linear minimization process. The execution time is faster and it facilitates the selection of the best fit of species. A series of 14 programs are introduced to run on a low memory microcomputer.

scholarly journals Shellfish Toxin Uptake and Depuration in Multiple Atlantic Canadian Molluscan Species: Application to Selection of Sentinel Species in Monitoring Programs

Toxins ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 168
Author(s):  
Wade A. Rourke ◽  
Andrew Justason ◽  
Jennifer L. Martin ◽  
Cory J. Murphy
Keyword(s):  
Monitoring Program ◽  
Sentinel Species ◽  
Paralytic Shellfish Toxins ◽  
Monitoring Programs ◽  
Paralytic Shellfish ◽  
Shellfish Toxin ◽  
Multiple Species ◽  
Toxin Uptake ◽  
Bivalve Shellfish ◽  
Selection Of

Shellfish toxin monitoring programs often use mussels as the sentinel species to represent risk in other bivalve shellfish species. Studies have examined accumulation and depuration rates in various species, but little information is available to compare multiple species from the same harvest area. A 2-year research project was performed to validate the use of mussels as the sentinel species to represent other relevant eastern Canadian shellfish species (clams, scallops, and oysters). Samples were collected simultaneously from Deadmans Harbour, NB, and were tested for paralytic shellfish toxins (PSTs) and amnesic shellfish toxin (AST). Phytoplankton was also monitored at this site. Scallops accumulated PSTs and AST sooner, at higher concentrations, and retained toxins longer than mussels. Data from monitoring program samples in Mahone Bay, NS, are presented as a real-world validation of findings. Simultaneous sampling of mussels and scallops showed significant differences between shellfish toxin results in these species. These data suggest more consideration should be given to situations where multiple species are present, especially scallops.

Reaction of metallic nitrilotriacetates with histamine

1969 ◽  
Vol 47 (8) ◽  
pp. 1269-1273 ◽  
Author(s):  
A. L. Beauchamp ◽  
J. Israeli ◽  
H. Saulnier
Keyword(s):  
Potentiometric Titration ◽  
Formation Constants ◽  
Amino Group ◽  
Mixed Complex ◽  
Ph Values ◽  
Titration Curves ◽  
Terminal Amino ◽  
Complex Ion

Cu(II), Ni(II), Co(II), and Zn(II) nitrilotriacetates (MeX−) react with histamine nitrate (LH+) to form a protonated mixed complex MeXLH where the metal appears to be bound only to the tertiary imidazolic nitrogen of histaminium ion. At higher pH values the proton dissociates to yield a mixed complex ion MeXL− in which both the imidazolic nitrogen and the terminal amino group are coordinated. The formation constants of these species were calculated from the potentiometric titration curves.

scholarly journals Selection of Cosmological Models Using QSOs

1972 ◽  
Vol 44 ◽  
pp. 471-473
Author(s):  
R. C. Roeder
Keyword(s):  
General Relativity ◽  
Steady State ◽  
Emission Line ◽  
Cosmological Models ◽  
Present Evidence ◽  
Normal Galaxy ◽  
Steady State Model ◽  
Lower Limits ◽  
Best Fit ◽  
Selection Of

It is assumed that the QSOs are at cosmological distances as indicated by their emission-line redshifts. It is further assumed, as indicated by present evidence, that none of the 21 QSOs with emission-line redshifts, ze, of 2.0 ± 0.1 (or of the 30 with ze = 2.0 ± 0.2) is screened by an intervening normal galaxy. The simplest conclusion from these data is, then, that the screening probability must be less than 0.08 (or 0.06) at ze = 2.0. This, in turn, restricts allowable cosmological models in the (σ0, q0) diagram by providing lower limits for ß0 as a function of q0. One can also rank cosmological models in order of the probability that there be no screening of the 21 (or 30) objects. In either case the steady state model ranks higher than the general relativity models found by Peach to give the best fit in the (m – z) diagram.

scholarly journals Calibration of Manning’s roughness in non-instrumented rural basins using a distributed hydrological model

DYNA ◽  
2019 ◽  
Vol 86 (210) ◽  
pp. 164-173
Author(s):  
Carlos Andrés Caro Camargo ◽  
Oscar Fabián Pacheco Merchán ◽  
Hans Paul Sánchez Tueros
Keyword(s):  
Hydrological Model ◽  
Numerical Study ◽  
Research Work ◽  
Roughness Coefficient ◽  
Distributed Hydrological Model ◽  
The Standard Model ◽  
Saint Venant Equations ◽  
Volume Method ◽  
Best Fit ◽  
Selection Of

The purpose of this research work was to calibrate the Manning's roughness coefficient in rural non-instrumented basins using a distributed hydrological model. The process consisted of the selection of several basins with vegetal cover of forests and grasslands, and its subsequent experimental numerical study, in which the hydrological response hydrograph of each reference basin was obtained from the HEC-HMS software and the hydrograph to be calibrated was the Iber software, which is a hydrodynamic model based on the two-dimensional Saint Venant equations, solved by the finite volume method. Once the calibration process was carried out, the roughness coefficients with the best fit for each basin were identified with increases in precipitation, identifying the limitations of these values and the standard model used.

Type Synthesis of 3-DOF Spherical Parallel Manipulators Based on Screw Theory1

2004 ◽  
Vol 126 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Xianwen Kong ◽  
Cle´ment M. Gosselin
Keyword(s):  
Parallel Manipulator ◽  
Screw Theory ◽  
General Procedure ◽  
Kinematic Chain ◽  
Parallel Manipulators ◽  
Type Synthesis ◽  
Validity Condition ◽  
First Time ◽  
Spherical Parallel Manipulator ◽  
Selection Of

A spherical parallel manipulator (SPM) refers to a 3-DOF (degree-of-freedom) parallel manipulator generating 3-DOF spherical motion. A method is proposed for the type synthesis of SPMs based on screw theory. The wrench systems of a spherical parallel kinematic chain (SPKC) and its legs are first analyzed. A general procedure is then proposed for the type synthesis of SPMs. The type synthesis of legs for SPKCs, the type synthesis of SPKCs, as well as the selection of inputs of SPMs are dealt with in sequence. An input validity condition of SPMs is proposed. SPKCs with and without inactive joints are synthesized. The number of overconstraints of each SPKC is also given. The phenomenon of dependent joint groups in an SPKC is revealed for the first time.

scholarly journals Best Fit and Selection of Theoretical Flood Frequency Distributions Based on Different Runoff Generation Mechanisms

Water ◽  
2010 ◽  
Vol 2 (2) ◽  
pp. 239-256 ◽  
Author(s):  
Vito Iacobellis ◽  
Mauro Fiorentino ◽  
Andrea Gioia ◽  
Salvatore Manfreda
Keyword(s):  
Flood Frequency ◽  
Runoff Generation ◽  
Frequency Distributions ◽  
Generation Mechanisms ◽  
Best Fit ◽  
Selection Of

Fletcher–Powell minimization of analytical potentiometric data by microcomputer: application to the Cu(II) complexes of biological polyamines

1985 ◽  
Vol 63 (11) ◽  
pp. 3122-3128 ◽  
Author(s):  
Douglas M. Templeton ◽  
Bibudhendra Sarkar
Keyword(s):  
Biological Activity ◽  
Metal Complex ◽  
Stability Constants ◽  
Speciation Analysis ◽  
Complex Stability ◽  
Minimization Algorithm ◽  
The Stability ◽  
Best Fit ◽  
Complex Stability Constants ◽  
Potentiometric Data

The Fletcher–Powell minimization algorithm has been successfully implemented for the extraction of metal complex stability constants from analytical potentiometric data. The procedure has been adapted to run on a microcomputer with acceptable execution times, and several strategies are employed to speed convergence and avoid false minima. This allows economical minimization for a large number of models of speciation, and improves the reliability of the proposed best fit by encouraging the checking of more models than previously possible. The Ni(II)–glycine system has been analyzed and excellent agreement with the stability constants of an earlier multi-laboratory study has been attained. The system proves useful in the evaluation of both analytical and computational methods. The procedure has also been used for speciation analysis of the Cu(II) complexes of the growth regulating polyamines, spermine, and spermidine. Both systems form fully deprotonated complexes at physiological pH, which are relevant to their biological activity.

Zinc(II)cysteine and zinc(II)cystine systems: Selection of species from potentiometric data

1980 ◽  
Vol 5 (1) ◽  
pp. 297-299 ◽  
Author(s):  
Giuseppe Arena ◽  
Salvatore Musumeci ◽  
Enrico Rizzarelli ◽  
Silvio Sammartano ◽  
Carmelo Rigano
Keyword(s):  
Selection Of Species ◽  
Selection Of ◽  
Potentiometric Data
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