The Migration of Extender Oil in Natural and Synthetic Rubber. VI. The Use of Oil Type Molecules as Penetrants to Elucidate Elastomeric Molecular Structure

1972 ◽  
Vol 45 (1) ◽  
pp. 278-292 ◽  
Author(s):  
B. G. Corman ◽  
M. L. Deviney ◽  
L. E. Whittington
Keyword(s):  
Free Volume ◽  
Critical Size ◽  
Cross Sectional Area ◽  
Rubber Matrix ◽  
Sectional Area ◽  
Fractional Free Volume ◽  
Cross Sectional ◽  
Expansion Technique ◽  
The Matrix ◽  
Volume Measurements

Abstract Previous work in diffusion of whole extender oil and extender oil fractions in practical rubber compounds has shown the nature of the rubber matrix to be the major controlling factor. Therefore, a sensitive diffusivity approach, using radiotracer labeled hydrocarbon penetrants of sizes comparable to the size of a rotating segment, was used to study various aspects of the matrix structure on penetrant diffusion for polybutadiene, styrene—butadiene, and Butyl rubbers. These results were compared with fractional free volume measurements made by a thermal expansion technique. Neither fractional free volume nor diffusivity of phenyldodecane, benz-a-anthracene, or n-octadecane was affected by 5-fold variations of crosslink density or by variations in loading of 10 to 80 parts of carbon black (HAF-LS); nor were they affected by changes from FEF to SAF black at a 50 phr level. Glass transition temperature and fractional free volume are both affected by increasing percentages of benzene or phenyldodecane, While diffusivity rises with increasing dilution, states of equal free volume in different elastomers are not states of equal diffusivity; for example, at a fractional free volume of 0.10, corresponding to 20% benzene in both polybutadiene and Butyl at 70° C, the diffusivity of benzene in Butyl is lower by a factor of 15. Comparison of diffusivity of large penetrants with their cross-sectional area gives two basic curves, one for flexible penetrants and another for molecularly rigid species. These results are explained in terms of a distribution of free volumes, wherein only holes above a critical size are effective in diffusion. Swelling the system with aromatic diluent greatly increases the total fractional free volume, but only slightly the number of holes above this critical size. To understand the diffusivity of rigid molecules in elastomers, a probability factor must be applied in estimating their effective cross-sectional area.

Lung Tumor Growth: Assessment with CT—Comparison of Diameter and Cross-sectional Area with Volume Measurements

Radiology ◽  
2004 ◽  
Vol 231 (3) ◽  
pp. 866-871 ◽  
Author(s):  
S. Gregory Jennings ◽  
Helen T. Winer-Muram ◽  
Robert D. Tarver ◽  
Mark O. Farber
Keyword(s):  
Tumor Growth ◽  
Lung Tumor ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Volume Measurements ◽  
Growth Assessment

scholarly journals Ultrastructure of mesophyll cells of Arabidopsis (Arabidopsis thaliana L.) after hyperthermia

2021 ◽  
Vol 85 (2) ◽  
pp. 15-22
Author(s):  
Yu. Akimov
Keyword(s):  
Cross Sectional Area ◽  
Growth Chamber ◽  
Sectional Area ◽  
Mesophyll Cells ◽  
Cross Sectional ◽  
The Matrix ◽  
Experimental Variant ◽  
The Cross ◽  
Palisade Cells ◽  
Night Illumination

The influence of hyperthermia (33 ºC, 2 days) on the ultrastructure of palisade cells of mesophyll of the first rosette leaves of arabidopsis Columbia 0 ecotype (Col-0, phases 1.02–1.04) was studied. Samples of 12-day-old seedlings were selected in 2 variants: control and 2 days 33 ºC. Seedlings of the control variant were grown in a growth chamber with a photoperiod of 15/9 hours. (day/night), illumination 5.5 klx, 75 % humidity and temperature 22 ºC. In the experimental variant containers with 9-day-old seedlings were transferred for 2 days to a growth chamber with a preset light 5.5 klx and temperature 33 ºC, with a photoperiod of 15/9 hours. The conducted ultrastructural analysis allowed to reveal the spectrum of rearrangements of palisade cells after two-day action of high (33 ºC) temperature. It was shown that the high temperature negatively affected size of mesophyll palisade cells, the cross-sectional area of which was 12 % smaller than in the control. Chloroplasts show an increase in granality: in the control granas contained 6–10 thylakoids, often combining into larger granas, up to 20 or more thylakoids in the intersection zone, while after two-day hyperthermia the granas contained 20 or more thylakoids, often forming giant granas of 60 and more thylakoids, the average cross-sectional area of starch granules decreased by almost half: 0.99 μm2 compared to 1.92 μm2 in the control, the diameter of plastoglobuli increased 3–4 times: to 100–200 nm compared to 30–50 nm in the control. In mitochondria, there was a decrease in the partial volume of the cristae, enlightenment of the matrix, the cross-section of mitochondria increased at least twice: 1 μm2 compared to 0.44 μm2 in the control. The mean cross-sectional area of peroxisomes also increased at least twice, to 1.36 μm2 compared with 0.77 μm2 in the control.

Pelvic Canal Narrowing Caused by Triple Pelvic Osteotomy in the Dog

1994 ◽  
Vol 07 (03) ◽  
pp. 110-113 ◽  
Author(s):  
D. L. Holmberg ◽  
M. B. Hurtig ◽  
H. R. Sukhiani
Keyword(s):  
Postoperative Complications ◽  
Pelvic Osteotomy ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Canal Width ◽  
Operative Complications ◽  
Post Operative Complications

SummaryDuring a triple pelvic osteotomy, rotation of the free acetabular segment causes the pubic remnant on the acetabulum to rotate into the pelvic canal. The resulting narrowing may cause complications by impingement on the organs within the pelvic canal. Triple pelvic osteotomies were performed on ten cadaver pelves with pubic remnants equal to 0, 25, and 50% of the hemi-pubic length and angles of acetabular rotation of 20, 30, and 40 degrees. All combinations of pubic remnant lengths and angles of acetabular rotation caused a significant reduction in pelvic canal-width and cross-sectional area, when compared to the inact pelvis. Zero, 25, and 50% pubic remnants result in 15, 35, and 50% reductions in pelvic canal width respectively. Overrotation of the acetabulum should be avoided and the pubic remnant on the acetabular segment should be minimized to reduce postoperative complications due to pelvic canal narrowing.When performing triple pelvic osteotomies, the length of the pubic remnant on the acetabular segment and the angle of acetabular rotation both significantly narrow the pelvic canal. To reduce post-operative complications, due to narrowing of the pelvic canal, overrotation of the acetabulum should be avoided and the length of the pubic remnant should be minimized.

DETERMINATION OF THE FUNCTION OF THE ROD’S CROSS-SECTIONAL AREA USING VIBRATION EIGENFREQUENCIES

2020 ◽  
Vol 0 (4) ◽  
pp. 19-24
Author(s):  
I.M. UTYASHEV ◽  
◽  
A.A. AITBAEVA ◽  
A.A. YULMUKHAMETOV ◽  
◽  
...  
Keyword(s):  
Cross Sectional Area ◽  
Variable Cross ◽  
Sectional Area ◽  
Longitudinal Vibrations ◽  
Cross Sectional ◽  
Method Error ◽  
Various Boundary Conditions ◽  
Elastic Fixation ◽  
Crosssectional Area

The paper presents solutions to the direct and inverse problems on longitudinal vibrations of a rod with a variable cross-sectional area. The law of variation of the cross-sectional area is modeled as an exponential function of a polynomial of degree n . The method for reconstructing this function is based on representing the fundamental system of solutions of the direct problem in the form of a Maclaurin series in the variables x and λ. Examples of solutions for various section functions and various boundary conditions are given. It is shown that to recover n unknown coefficients of a polynomial, n eigenvalues are required, and the solution is dual. An unambiguous solution was obtained only for the case of elastic fixation at one of the rod’s ends. The numerical estimation of the method error was made using input data noise. It is shown that the error in finding the variable crosssectional area is less than 1% with the error in the eigenvalues of longitudinal vibrations not exceeding 0.0001.

Changes in the parameters of nasal breathing and parameters of the upper respiratory tract during orthognathic operations in patients with II and III skeletal class of jaw anomalies

2020 ◽  
pp. 22-27
Author(s):  
S.Sh. Gammadaeva ◽  
M.I. Misirkhanova ◽  
A.Yu. Drobyshev
Keyword(s):  
Respiratory Tract ◽  
Nasal Cavity ◽  
Nasal Septum ◽  
Cross Sectional Area ◽  
Upper Respiratory Tract ◽  
Sectional Area ◽  
Nasal Breathing ◽  
Cross Sectional ◽  
Skeletal Class ◽  
Upper Respiratory

The study analyzed the functional parameters of nasal breathing, linear parameters of the nasal aperture, nasal cavity and nasopharynx, volumetric parameters of the upper airways in patients with II and III skeletal class of jaw anomalies before and after orthognathic surgery. The respiratory function of the nose was assessed using a rhinomanometric complex. According to rhinoresistometry data, nasal resistance and hydraulic diameter were assessed. According to the data of acoustic rhinometry, the minimum cross-sectional area along the internal valve, the minimum cross-sectional area on the head of the inferior turbinate and nasal septum and related parameters were estimated. According to the CBCT data, the state of the nasal septum, the inferior turbinates, the nasal aperture, the state of the nasal cavity, and the linear values of the upper respiratory tract (nasopharynx) were analyzed. The patients were divided into 4 groups according to the classification of the patency of the nasal passages by

Unequal Probability Scheme for Fruit Count in a Guava Tree

2016 ◽  
Vol 3 (4) ◽  
Author(s):  
R. C. BHARATI
Keyword(s):  
Cross Sectional Area ◽  
Equal Probability ◽  
Sampling Scheme ◽  
Research Station ◽  
Sectional Area ◽  
Cross Sectional ◽  
Unequal Probability ◽  
Selection Probabilities ◽  
Horticultural Research ◽  
Number Of Branches

Data on fruit count corresponding to primary, secondary and tertiary branches of a randomly selected guava CV. Allahabad Safeda were recorded from the guava orchard of Horticultural Research Station, Birauli. The proposed sampling scheme in which the selection probabilities are based on length of braches between two forking points was compared with equal probability(PE), probability proportional to the number of branches(PPN), probability proportional to the cross sectional area (PPA) and probability proportional to volume (PPV) method of sampling and found to be more efficient.

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