scholarly journals Solution Properties of Combretum Glutinosum (Habeil) Gum

2015 ◽  
Vol 7 (2) ◽  
pp. 49
Author(s):  
M. Awad
Keyword(s):  
Ionic Strength ◽  
Salt Tolerance ◽  
Intrinsic Viscosity ◽  
Distilled Water ◽  
Solution Properties ◽  
Stiffness Parameter ◽  
Chain Stiffness ◽  
Reduced Viscosity ◽  
Gel Fraction ◽  
Optimum Model

The solubility of Combretum glutinosum gum in distilled water ranged from 30 to 40% and gel fraction ranges between 60 to 70%. It was found that the gum solubility increased with increase the pH of solution. The reduced viscosity of Gum Habeil in distilled water was increased with decrease the concentration of gum solution, and this is the a behavior of ionic polysaccharide solutions, for that Huggins and Kraemer equations are incapable to derive the intrinsic viscosity value of aqueous gum solution. Some extrapolated equations such as Fouss, Schulz –Blaschke, Martin, Heller, and Fedors equations used to estimate the optimum model for measurement intrinsic viscosity of this type of gum. The influence of ion types and ionic strength on the viscosity of gum solutions were also determined. The effect of ionic strength on the intrinsic viscosity of Combretum glutinosum gum was used to determine the salt tolerance value and the chain stiffness parameters of this type of gum. This study exhibited that the values of chain stiffness parameter (B), and salt tolerance (S) of deacetylated gum in the range of 0.0574 to 0.0700, and0.083 to 0.101 dl× M1/2 / g respectively.

Viscosimetric studies of chitosan nitrate and chitosan chlorhydrate in acid free NaCl aqueous solution

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Cristóbal Lárez Velásquez ◽  
Joel Sánchez Albornoz ◽  
Enrique Millán Barrios
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Aqueous Solutions ◽  
Aqueous Medium ◽  
Intrinsic Viscosity ◽  
Free Acid ◽  
Film Formation ◽  
Stiffness Parameter ◽  
Low Ionic Strength

AbstractTwo salts of the biopolymer chitosan were prepared in aqueous medium by employing an excess of HCl or HNO3 in order to ensure neutralization of all NH2-chitosan groups. Chitosan salts were extensively dialyzed in dionised water and dried at 40 ºC until film formation. The films were characterized by thermogravimetry, FTIR and conductimetric tritration. QH+Cl− and QH+NO3− salts were viscosimetrically evaluated in free acid aqueous solutions in the presence of NaCl to control ionic strength of the medium. Unexpected high intrinsic viscosity values were obtained at low ionic strength when QH+NO3− salt were evaluated. Smidsrod´s approach was employed to estimate the stiffness parameter of both salts and B = 0.084 and 0.120 for QH+Cl− and QH+NO3−, respectively, were obtained.

Challenges in Determining Intrinsic Viscosity Under Low Ionic Strength Solution Conditions

2017 ◽  
Vol 34 (4) ◽  
pp. 836-846 ◽  
Author(s):  
Mariya A. Pindrus ◽  
Steven J. Shire ◽  
Sandeep Yadav ◽  
Devendra S. Kalonia
Keyword(s):  
Ionic Strength ◽  
Intrinsic Viscosity ◽  
Low Ionic Strength

Solution Properties of Gellan Gum:  Change in Chain Stiffness between Single- and Double-Stranded Chains

2004 ◽  
Vol 5 (2) ◽  
pp. 516-523 ◽  
Author(s):  
Rheo Takahashi ◽  
Hiroshi Tokunou ◽  
Kenji Kubota ◽  
Etsuyo Ogawa ◽  
Tatsuo Oida ◽  
...  
Keyword(s):  
Gellan Gum ◽  
Solution Properties ◽  
Chain Stiffness

Experiments on Substrate Selection by Corophium Species: Films and Bacteria on Sand Particles

1964 ◽  
Vol 41 (3) ◽  
pp. 499-511
Author(s):  
P. S. MEADOWS
Keyword(s):  
Ionic Strength ◽  
Sea Water ◽  
Distilled Water ◽  
Substrate Selection ◽  
Corophium Volutator ◽  
Simple Method ◽  
Substrate Preferences ◽  
Solutions Of Electrolytes ◽  
Sand Particles ◽  
Micro Organisms

1. A simple method is described for determining the substrate preferences of Corophium volutator (Pallas) and Corophium arenarium Crawford. 2. If offered a choice of its own substrate with that of the other species each prefers its own. 3. Level of illumination and colour of substrate have little effect on choice. An animal's size and hence its age has little effect on its substrate preferences. 4. C. volutator prefers a substrate previously maintained under anaerobic conditions, C. arenarium vice versa. 5. Treatments which kill, inactivate, or remove micro-organisms render sands unattractive to Corophium. These include boiling, acid-cleaning, drying, and soaking in fixatives or distilled water. Attempts to make these sands attractive again failed. 6. Distilled water, and solutions of the non-electrolytes sucrose and glycerol at the same osmotic pressure as sea water, induce many bacteria to desorb from sand particles; smaller numbers are desorbed in the presence of solutions of electrolytes at the same ionic strength as sea water (NaCl, Na2SO4, KC1, MgSO4, MgCl2, CaCl2). Of all these, only distilled water and solutions of MgCl2 and CaCl2 reduce the attractive properties of sands. Hence the loss of bacteria from the surface of sand grains, though related to the ionic strength and composition of the medium, is not necessarily associated with a substrate becoming unattractive.

scholarly journals Effect of NaCl on seed germination in some Centaurium Hill. Species (Gentianaceae)

2007 ◽  
Vol 59 (3) ◽  
pp. 227-231 ◽  
Author(s):  
S. Zivkovic ◽  
M. Devic ◽  
B. Filipovic ◽  
Z. Giba ◽  
D. Grubisic
Keyword(s):  
Life History ◽  
Salt Tolerance ◽  
Seed Germination ◽  
Gibberellic Acid ◽  
White Light ◽  
The Other ◽  
Distilled Water ◽  
Nacl Concentration ◽  
History Of ◽  
Species Specific

The influence of high NaCl concentrations on seed germination in both light and darkness was examined in the species Centaurium pulchellum, C. erythraea, C. littorale, C. spicatum, and C. tenuiflorum. Salt tolerance was found to depend on the life history of the seeds. To be specific, seeds of all five species failed to complete germination when exposed to continuous white light if kept all the time in the presence of 100-200 mM and greater NaCl concentrations. However, when after two weeks NaCl was rinsed from the seeds and the seeds were left in distilled water under white light for an additional two weeks, all species completed germination to a certain extent. The percent of germination not only depended on NaCl concentration in the prior medium, but was also species specific. Thus, seeds of C. pulchellum, C. erythraea, and C. littorale completed germination well almost irrespective of the salt concentration previously experienced. On the other hand, seeds of C. tenuiflorum completed germination poorly if NaCl concentrations in the prior media were greater than 200 mM. When seeds after washing were transferred to darkness for an additional 14 days, they failed to complete germination if previously imbibed on media containing NaCl concentrations greater than 400 mM. However, the seeds of all species, even if previously imbibed at 800 mM NaCl, could be induced to complete germination in darkness by 1 mM gibberellic acid. .

Viscosity studies of polyvinyl alcohol (PVA, Mw = 1,25,000) in solvent distilled water and aqueous solution of urea

2010 ◽  
Vol 7 (2) ◽  
pp. 443-448
Author(s):  
S. Panda ◽  
G. C. Mohanty ◽  
R.N. Samal ◽  
G. S. Roy
Keyword(s):  
Aqueous Solution ◽  
Polyvinyl Alcohol ◽  
Polymer Solution ◽  
Flow Time ◽  
Inherent Viscosity ◽  
Distilled Water ◽  
Reduced Viscosity ◽  
Aqueous Urea ◽  
C 30

Reduced viscosity (ηsp/C) and inherent viscosity ln (ηrel/C) of PVA (Mw = 1,25,000) has been calculated by measuring the flow time of polymer solution in solvents like distilled water and 4M Urea at six different tempratures 25° C, 30° C, 35° C, 40° C, 45° C, and 50° C. From exptrapolation of curve (/C) versus C and (ln /C) versus C, thermoviscosity parameters like Huggins’ Constrant (KHl), Kraemer's constant (KHll) and viscosity concentration co-efficient (a2) have been estimated. In aqueous solution (PVA in distilled water), Huggins' relation does not hold good. So a2 = .201[h]2.28 is used; but in aqueous Urea (PVA in 4M Urea), Huggins' relation holds good. Also η =KMα and value of a more for 4M Urea i.e aqueous Urea is better solvent for PVA than distilled water.

The Terminology of Intrinsic Viscosity and Related Functions

1946 ◽  
Vol 19 (4) ◽  
pp. 1092-1098
Author(s):  
L. H. Cragg
Keyword(s):  
Intrinsic Viscosity ◽  
Kinematic Viscosity ◽  
Relative Viscosity ◽  
Flow Time ◽  
Inherent Viscosity ◽  
Routine Practice ◽  
Concentration Coefficient ◽  
Specific Viscosity ◽  
Reduced Viscosity ◽  
Relative Flow

Abstract The confusion existing in the use of symbols and names for Kraemer's “intrinsic viscosity” and other functions related to it is illustrated and deplored. The reasonable plea is made that one name be adopted for each function and that it be used with no other meaning. To stimulate discussion and ultimate action, the following names are proposed: “specific viscosity” for ηsp; “reduced viscosity” for ηsp/c, “inherent viscosity” for (ln ηr)/c; and “intrinsic viscosity” for [η], whether determined as “limiting reduced viscosity” limc→0 (ηsp/c), or as “limiting inherent viscosity” limc→0 (ηr/c), or as “limiting viscosity concentration coefficient” limc→0 (dηr/dc). Often, especially in routine practice, it is the relative kinematic viscosity νr, that is determined ; unless this is shown to be numerically equal to the relative viscosity ηr, the symbols and names of the derived functions should be modified accordingly: thus, (ln νr)/c inherent kinematic viscosity, [ν] intrinsic kinematic viscosity. Frequently, also, kinetic energy corrections are neglected; under these circumstances the suggested usage is tr, relative flow time, tsp/c reduced flow time, [t] intrinsic flow time, etc.

Sign in / Sign up

Export Citation Format

Share Document