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Logarithmic Relationship (logarithmic + relationship)
Selected AbstractsTEXTURE PROFILE ANALYSIS , HOW IMPORTANT ARE THE PARAMETERS?JOURNAL OF TEXTURE STUDIES, Issue 5 2010ANDREW J. ROSENTHAL ABSTRACT A starch-glycerol gel was subjected to a two-bite compression test using two sample-instrument geometries, various speeds of compression and strain levels, both with lubrication or not. Results were interpreted using the primary characteristic terminology previously defined in Texture Profile Analysis. Compression speeds from 0.1 to 10 m/s showed a logarithmic relationship with hardness, cohesiveness, corrected cohesiveness and adhesiveness. Gels survived compression to strains of 0.90 without failing, strain levels from 0.25 to 0.90 resulted in an exponential rise in hardness with increasing strain and linear reduction in corrected cohesiveness. Lubrication had no significant influence on any of the measured parameters and an application of force with different sample-instrument geometry revealed that parallel plates and plungers only had an influence on gel hardness. Caution is urged when researchers modify the test protocol from 75% deformation with parallel plates. A minimum crosshead speed of 2 mm/s is recommended. PRACTICAL APPLICATIONS Texture Profile Analysis has been widely applied to test solid and semisolid foods; however, some researchers deviate from the original test protocol. This article attempts to show how modifying the parameters in the test protocol can influence the apparent properties of the sample. [source] In-line optical detection in the transient state of extrusion polymer blending and reactive processing,,POLYMER ENGINEERING & SCIENCE, Issue 1 2005Tomás Jeferson A. Mélo Using an opticaldetector we followed the transient state of blends and composites, including a reactive blending during extrusion. The detection system is composed of a slit-die with transparent windows fixed at the extruder exit, an optical arrangement with a W incandescent light microbulb with fixed luminescence, and a CdS photocell. As the tracer passes though the light path, it absorbs and backscatters part of the light, reducing the total transmitted light intensity. This is followed by changes in the voltage induced by the photocell to an electric circuit. We calibrated the response of the photocell at room temperature using a set of various films with a second phase dispersed, and obtained a logarithmic relationship. The tracers were particulate (phthalocyanine, TiO2) and polymeric (PS, PA6) phases that absorb and scatter light, producing a residence time distribution (RTD) curvelike trace. Measurements were taken from a twin-screw extruder Werner-Pfleiderer ZSK 30 equipped with K-Tron gravimetric feeders operating at various screw configurations and speeds, and feeding rates. The transient state of PP/PA6 blends can be easily detected optically and recorded using one of the components (either PP or PA6) added as a pulse in a steady-state flow of the other component. With the simultaneous addition of a compatibilizer (polypropylene grafted with acrylic acid (PP-g-AA)) with the PA6, the intensity of the detector signal is substantially increased as a result of the PA6/PP-g-AA reaction. Quantitative off-line infrared spectroscopy of the total amide group corroborated the in-line measurements. These observations suggest that an in-line optical detector may be a fast and simple way to study the flow behavior of blends and composites, including reactive processing. POLYM. ENG. SCI. 45:11,19, 2005. © 2004 Society of Plastics Engineers. [source] An optical device to measure in-line residence time distribution curves during extrusionPOLYMER ENGINEERING & SCIENCE, Issue 1 2002Tomás Jeferson A. Mélo This paper proposes a setup for in-line measurement of residence time distribution (RTD) curves during extrusion. The detection system is composed of a slit die with transparent borosilicate glass windows fixed at the extruder exit, an optical arrangement with an incandescent light microbulb with fixed luminescence, and a Light Dependent Resistor (LDR) photocell of CdS. As the tracer passes through the light path, the reduction in the transmitted light intensity is followed by changes in the voltage induced by the photocell to an electric circuit. The signal is collected by an external interface and sent to a computer. Software acquires the data, does all calculations, and presents all curves and calculated variables to the monitor. The validation of the system was done by checking for data reproducibility and linearity with tracer concentration. The response of the LDR sensor with respect to the concentration of the tracer was calibrated using a set of slight dark film, obtaining a logarithmic relationship. Thus the signal enhances any disturbance, if present, particularly in the tail-region of the curves. Measurements were taken from a Werner-Pfleiderer ZSK 30 twin-screw extruder equipped with K-Tron gravimetric feeders operating with various screw speeds, feeding rates and screw configurations. In this last case, the presence of kneading elements was taken into account. [source] New Aspects of Impact Reactivity of Polynitro Compounds, Part III.PROPELLANTS, EXPLOSIVES, PYROTECHNICS, Issue 6 2003Impact Sensitivity as a Function of the Imtermolecular Interactions Abstract Published data of impact sensitivity of 33 polynitro compounds detected by sound were expressed as the drop energy, Edr, required for 50 percent initiation probability. A logarithmic relationship has been found between the Edr values and heats of fusion of the said compounds. The relationship has been found to be in accordance with the idea concerning the role of plastic deformations of crystal played in the initiation of energetic materials by impact and shock. An analogous application of heats of sublimation has not given convincing results. [source] | ||||||||||