Ibuprofen-loaded ethylcellulose microspheres: Release studies and analysis of the matrix structure through the Higuchi model

1990 ◽  
Vol 7 (4) ◽  
pp. 555-565 ◽  
Author(s):  
C. Dubernet ◽  
J. P. Benoit ◽  
N. A. Peppas ◽  
F. Puisieux
Keyword(s):  
Matrix Structure ◽  
Release Studies ◽  
The Matrix ◽  
Higuchi Model

Formation of Persistent Slip Band in Fatigued Copper Single Crystals

1982 ◽  
Vol 40 ◽  
pp. 470-471
Author(s):  
N. Y. Jin
Keyword(s):  
Volume Fraction ◽  
Fatigue Cracks ◽  
Wall Structure ◽  
Matrix Structure ◽  
Dislocation Dipole ◽  
Slip Bands ◽  
Persistent Slip Bands ◽  
The Matrix ◽  
Hard Shell ◽  
Copper Single Crystals

Localised plastic deformation in Persistent Slip Bands(PSBs) is a characteristic feature of fatigue in many materials. The dislocation structure in the PSBs contains regularly spaced dislocation dipole walls occupying a volume fraction of around 10%. The remainder of the specimen, the inactive "matrix", contains dislocation veins at a volume fraction of 50% or more. Walls and veins are both separated by regions in which the dislocation density is lower by some orders of magnitude. Since the PSBs offer favorable sites for the initiation of fatigue cracks, the formation of the PSB wall structure is of great interest. Winter has proposed that PSBs form as the result of a transformation of the matrix structure to a regular wall structure, and that the instability occurs among the broad dipoles near the center of a vein rather than in the hard shell surounding the vein as argued by Kulmann-Wilsdorf.

scholarly journals In vitro Release Kinetics Study of Ranolazine from Swellable Hydrophilic Matrix Tablets

1970 ◽  
Vol 8 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Mohammad Nezab Uddin ◽  
Ishtiaq Ahmed ◽  
Monzurul Amin Roni ◽  
Muhammad Rashedul Islam ◽  
Mohammad Habibur Rahman ◽  
...  
Keyword(s):  
Drug Release ◽  
Sustained Release ◽  
Release Kinetics ◽  
In Vitro Release ◽  
High Viscosity ◽  
Matrix Tablets ◽  
Release Studies ◽  
The Matrix ◽  
Vitro Release

The objective of this study was to design oral sustained release matrix tablets of Ranolazine usinghydroxypropyl methylcellulose (HPMC) as the retardant polymer and to study the effect of formulation factors suchas polymer proportion and polymer viscosity on the release of drug. In vitro release studies were performed usingUSP type II apparatus (paddle method) in 900 mL of 0.1N HCl at 100 rpm for 12 hours. The release kinetics wasanalyzed using the zero-order, first order, Higuchi and Korsmeyer-Peppas equations to explore and explain themechanism of drug release from the matrix tablets. In vitro release studies revealed that the release rate decreasedwith increase in polymer proportion and viscosity grade. Mathematical analysis of the release kinetics indicated thatthe nature of drug release from the matrix tablets was dependent on drug diffusion and polymer relaxation andtherefore followed non-Fickian or anomalous release. The developed controlled release matrix tablets of Ranolazineprepared with high viscosity HPMC extended release up to 12 hours.Key words: Ranolazine; Sustained release; Methocel E50 Premium LV; Methocel K100LV CR; Methocel K4M CR;Methocel K15M CR.DOI: 10.3329/dujps.v8i1.5333Dhaka Univ. J. Pharm. Sci. 8(1): 31-38, 2009 (June)

Loop patch orientations in the matrix structure of cyclically deformed copper

1988 ◽  
Vol 101 ◽  
pp. 75-85 ◽  
Author(s):  
J.I. Dickson ◽  
Hong Bande ◽  
G. L'Espérance
Keyword(s):  
Matrix Structure ◽  
The Matrix

Comparison of Shear, Compressive and Tensile Characteristics of Cast Irons

1973 ◽  
Vol 15 (1) ◽  
pp. 53-60 ◽  
Author(s):  
R. D. Adams ◽  
M. A. O. Fox
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Design Criteria ◽  
Matrix Structure ◽  
Proof Stress ◽  
Cast Irons ◽  
The Matrix ◽  
The Relationship ◽  
Graphite Inclusions ◽  
Strength And Ductility

Cast irons were produced with variations in the quantity and shape of the free graphite inclusions and in the matrix structure to investigate the relationship between the shear, compressive and tensile mechanical properties. Differences were observed which may have a significant effect on design criteria for cast irons. For example, the ratio of shear to tensile strengths decreased from about 1·25 to 0·577 and the ratio of 0·1 per cent proof stress in compression to that in tension decreased from approximately 2 to 11 as the tensile strength (and ductility) were increased.

Color Image Compression Using Block Singular Value Decomposition

2013 ◽  
Vol 303-306 ◽  
pp. 2122-2125
Author(s):  
Peng Fei Xu ◽  
Hong Bin Zhang ◽  
Xin Feng Wang ◽  
Zheng Yong Yu
Keyword(s):  
Singular Value Decomposition ◽  
Image Compression ◽  
Basic Principle ◽  
Color Image ◽  
Singular Value ◽  
Matrix Structure ◽  
Compression Scheme ◽  
The Matrix ◽  
Value Decomposition ◽  
Color Image Compression

This paper looks at the application of Singular Value Decomposition (SVD) to color image compression. Based on the basic principle and characteristics of SVD, combined with the image of the matrix structure. A block SVD-based image compression scheme is demonstrated and the usage feasibility of Block SVD-based image compression is proved.

scholarly journals Matrix structure of unified mathematical model of electric AC machines at control

2020 ◽  
Vol 209 ◽  
pp. 02023
Author(s):  
Rauf Mustafayev ◽  
Nurali Yusifbayli ◽  
Laman Hasanova
Keyword(s):  
Frequency Control ◽  
Synchronous Machine ◽  
Matrix Structure ◽  
Asynchronous Machine ◽  
Asynchronous Machines ◽  
Squirrel Cage ◽  
The Matrix ◽  
Almost All ◽  
Cage Rotor ◽  
Derivatives Of

The matrix structure of the equations of a generalized electric alternating current machine is proposed, which, based on the Parke equations, is written in the coordinate axes of the machines rotating with the rotor speed. In the matrix structure, the column matrices of the derivatives of the stator, excitation and rotor windings are equal to the product of diagonal matrices consisting of the machine parameters and the column matrices of the flux links themselves and the sum of the matrix columns of the control parameters which are the matrix columns of the stator voltage, excitation voltage, and rotor voltage. It is shown that the matrix structure of a generalized controlled AC machine is transformed into mathematical models of almost all encountered AC electric machines, namely, into a synchronous machine with two excitation windings - a longitudinal and a transverse one; in a synchronous machine with a longitudinal field winding (classic); in an asynchronous machine with a squirrel-cage rotor; into an asynchronous machine with a phase rotor. It has been shown that the matrix structure includes the controls of these machines both from the stator and from the rotor. On the stator side for synchronous machines, it is a frequency control that regulates both the amplitude and frequency of the applied voltage, and on the rotor side, a constant voltage control is supplied to the longitudinal and transverse windings. For asynchronous machines, the stator and rotor are frequency-controlled. The following are examples of frequency control of an asynchronous machine both from the stator and from the rotor.

scholarly journals Designing matrix organizations that work: Lessons from the P&G case

2009 ◽  
Vol 2 (1) ◽  
pp. 179 ◽  
Author(s):  
Ronald Jean Degen
Keyword(s):  
Structure Design ◽  
Matrix Structure ◽  
Systems Planning ◽  
The Us ◽  
The Matrix ◽  
Simple Matrix ◽  
Proper Power ◽  
Matrix Organization ◽  
The 1960S ◽  
Information Systems Planning

The matrix organization concept emerged from the US aerospace industry in the 1960s and was adopted by many companies in the early 1970s. In the late 1970s and early 1980s many companies were experiencing trouble with its operation and many argued like Peters & Waterman in their bestseller In search of excellence in 1982 (p. 306) that the matrix was too complex to work properly. Galbraith (2009, p. 10-14) explains that the reason for the problems were that the matrix in these organizations was wrongly adopted, hastily installed, and inappropriately implemented. He explains that adopting a matrix structure requires a collaborative organization form, proper power, and accountability distribution, complementing changes to the information systems, planning and budgeting process, the performance evaluation and bonus system, and so on. The purpose of this paper is to illustrate why companies adopted the matrix, what problems they had, the solutions for these problems based on Galbraith (2009) and other authors like Davis & Lawrence (1977), and the state of the art of matrix structure design today like the P&G front-back hybrid matrix organization. To illustrate the historical evolution of organization structure to the simple matrix and then to more complex matrix organizations we used the P&G case (Piskorski & Spadini 2007).

scholarly journals Development of Lung Edema: Interstitial Fluid Dynamics and Molecular Structure

Physiology ◽  
2001 ◽  
Vol 16 (2) ◽  
pp. 66-71 ◽  
Author(s):  
Giuseppe Miserocchi ◽  
Daniela Negrini ◽  
Alberto Passi ◽  
Giancarlo De Luca
Keyword(s):  
Molecular Structure ◽  
Enzymatic Degradation ◽  
Interstitial Fluid ◽  
Capillary Permeability ◽  
Basal Membrane ◽  
Lymphatic Drainage ◽  
Lung Edema ◽  
Matrix Structure ◽  
Tissue Compliance ◽  
The Matrix

Pulmonary interstitium is maintained dehydrated at subatmospheric pressure (–10 cmH2O) through low capillary permeability, low tissue compliance, and an efficient lymphatic drainage. Enzymatic degradation of proteoglycans disrupts the endothelial basal membrane and the matrix structure, triggering the development of pulmonary edema.

Investigation of the Decorative Ceramics of Matrix Structure from Iron-Ore Waste with Vanadium Component Addition

2018 ◽  
Vol 931 ◽  
pp. 520-525 ◽  
Author(s):  
Andrey Y. Stolboushkin ◽  
Danil V. Akst
Keyword(s):  
Iron Ore ◽  
Raw Materials ◽  
Physical And Mechanical Properties ◽  
Ceramic Materials ◽  
Matrix Structure ◽  
Vanadium Slag ◽  
The Matrix ◽  
Color Form ◽  
Decorative Ceramic ◽  
Component Addition

Results of the study of bulk coloring of decorative ceramic materials with matrix structure based on the slurry part of the iron ore tailings by vanadium slag additive are represented. Chemical, mineralogical and granulometric compositions of the raw materials are presented. The characteristic of their ceramic-technological properties is given. A new method of obtaining decorative ceramic specimens with matrix structure is described. The dependence of physical and mechanical properties and ceramic specimen color form the vanadium slag amount in charge is established. The results of studies of the matrix structure of decorative ceramic specimens with different contents of the coloring additive are represented.

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