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Retention Value (retention + value)
Selected AbstractsEffect of prefabricated metal post-head design on the retention of various core materialsJOURNAL OF ORAL REHABILITATION, Issue 6 2000M. Zalkind Retention of various post heads to core restorative materials is an important factor in the selection of prefabricated post systems and restorative materials for the restoration of endodontically treated teeth. This study examines the retention of a post,core prefabricated system in relation to core material and post-head design. A total of 60 samples were prepared using two different post systems (ParaPost Plus® (PP) and ParaPost Unity® (PU), with amalgam, composite or glass,ionomer as one of the core materials. The samples were tested using the Instron testing machine. The PP was superior to the PU prefabricated post with respect to the retention of various core materials. Retention values in descending order of magnitude were found to be: composite, amalgam and glass,ionomer (significantly lower). The rhomboid serrated design of PP was superior in retention to the rounded smooth UP system. Composite material proved to be superior in retention, closely followed by amalgam, with glass,ionomer significantly less retentive. [source] Fat, wheat bran and salt effects on cooking properties of meat patties studied by response surface methodologyINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 10 2010Hasibe Tekin Summary Response surface methodology was used to investigate the main effects and interactions of composition (processing) variables such as fat (10,30%), wheat bran (5,15%) and NaCl (0,2%) on cooking properties of beef patties. In addition, the ridge analysis was conducted to find the values of processing variables that maximise and minimise the cooking parameters (moisture retention, fat retention, reduction in thickness, reduction in diameter, cooking yield, shrinkage and water-holding capacity). It was found that the moisture and fat retention, reduction in thickness and cooking yield values decreased; however, reduction in diameter and shrinkage values increased, respectively, as the amount of fat increased. However, wheat bran addition increased fat retention, moisture retention, cooking yield and water-holding capacity values of the patties. Increasing NaCl levels decreased water-holding capacity value by its quadratic effect and moisture and fat retention value by its interaction effect with wheat bran. [source] Application of ultrasonic waves in activation of microcrystalline celluloseJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2008Xianling Wang Abstract In this work, microcrystalline cellulose (MCC) was activated with ultrasonic waves. The influences of ultrasonic treatment on the changes of supramolecular structures and morphology structure were studied by WAXS and SEM. The accessibility of the MCC was characterized by water retention value (WRV) and specific surficial area. The influence of ultrasonic treatment on the reactivity of MCC was investigated through the reaction of MCC being oxidized into 2,3-diadehyde cellulose (DAC) by periodate sodium. The mechanism of the reactivity change of ultrasonically treated MCC was examined. The results showed that the degree of crystallinity of MCC decreased and the degree of polymerization showed little change after treatment with ultrasonic waves. The morphologial variation of the treated MCC was significant when compared with the untreated MCC, which contribute to the improvement of accessibility. The aldehyde content of DAC prepared from ultrasonically treated MCC was improved from 64.19 to 85.00%, indicating that the regioselective oxidation reactivity of MCC was significantly improved. The aldehyde content was found to first increase with time of ultrasonic treatment to a point, and then decrease as time progressed. In addition, the aldehyde content was found to increase with an increase in ultrasonic power. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Extremum-seeking control of retention for a microparticulate systemTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2008Audrey Favache Abstract The operation of a paper machine relies on the close monitoring and control of several integrated units to ensure a high quality paper with the required specifications. In this paper, the retention control system in the wet-end of a paper machine is considered. The control objective is to maximize the retention of fines and fibres in the paper sheet to prevent the accumulation of micro particles in the water system. We present an adaptive extremum-seeking scheme for the optimization and control of retention in the wet-end of a paper machine. An adaptive learning technique is introduced to construct an algorithm that drives the system to the optimal retention value. Lyapunov's stability theory is used in the design of the extremum-seeking controller structure and the development of the parameter learning laws. The performance of the technique is illustrated via simulations based on a first-principles dynamic model developed previously for a micro-particulate system. Le bon fonctionnement d'une machine à papier repose sur le suivi et le contrôle étroits de plusieurs unités intégrées afin d'assurer une haute qualité de papier ayant les spécifications requises. Dans cet article, on considère le système de contrôle de rétention dans la partie humide d'une machine à papier. L'objectif du contrôle est de maximiser la rétention des fines et des fibres dans la feuille de papier afin de prévenir l'accumulation de micro-particules dans le système d'eau. On présente un schéma de recherche adaptatif des extrêmes pour l'optimisation et le contrôle de la rétention dans la partie humide d'une machine à papier. Une technique d'apprentissage adaptative est introduite pour construire un algorithme qui amène le système à une valeur de rétention optimale. La théorie de stabilité de Lyapunov est utilisée dans la conception de la structure des contrôleurs de recherche des extrêmes et l'élaboration de lois d'apprentissage des paramètres. La performance de la technique est illustrée par des simulations basées sur un modèle dynamique fondamental mis au point antérieurement pour un système de micro-particules. [source] Low-temperature bath/coupled-capillary/sweeping-micellar electrokinetic capillary chromatography for the separation of naphthalene-2,3-dicarboxaldehyde-derivatized dopamine and norepinephrineELECTROPHORESIS, Issue 11 2005Chun-Min Shih Abstract The use of a low-temperature (0°C) bath-assisted coupled capillary for the separation of naphthalene-2,3-dicarboxaldehyde (NDA)-derivatized dopamine and norepinephrine using the sweeping-micellar electrokinetic capillary chromatography (MEKC) mode is described. In this technique, a capillary consisting of two portions with different inside diameters is used. Therefore, the field strength inside the capillary is different. Hence, the electrophoretic migration velocities of the analytes and the electroosmotic flow (EOF) also are different. Furthermore, when a portion of the capillary (wide portion, used for sweeping) is immersed in a low-temperature bath, the viscosity of the buffer and the retention factor of the analytes inside are increased. Thus, not only are the interactions between the SDS micelles and the analytes increased, but the SDS-analytes also move more slowly. As a result, a more complete separation can be achieved, even when the sample injection volume is large, up to , 2 ,L. In general, when the volume of an injected sample is larger, the effects of sweeping and separation would become insufficient, especially when the retention values (k) of the analytes are quite different. However, this limitation can be improved when the low-temperature bath/coupled capillary/sweeping-MEKC mode is used. [source] Parameters affecting retentive force of conus crownsJOURNAL OF ORAL REHABILITATION, Issue 3 2004M.A. Güngör summary, The aim of this study was to determine the values of the retentive forces of the telescopic crowns. At the first step of the study, the samples having different heights and angles were compared in relation to retentive force. At the second step, the samples were subjected to removal procedures having a pre-determined speed, force and number. The obtained retention values were compared. Ninety dies were prepared in order to measure the retention of the conus crowns. The removal tests were performed with the insertion/separation device. The speed of the test device was 100 cm min,1 providing the placement of the pieces with 5 kgf in 100, 200, 300, 500, 1000, 5000 and 10 000 cycles. The mean of the retention values of the changes of the angles were found to be statistically different (P < 0,01). According to the results of the variant analysis, the differences in the changes of the height were statistically significant (P < 0·01). The differences between the changes of the number of procedures of all groups were statistically significant (P < 0·01). The number of procedures, height and angle interactions were statistically insignificant (P = 0·758). According to the results of this study, the effect of the angle and height factors in terms of retention among the groups were not independent of each other. In equal angles, as the height increased, increased retention measurements were obtained. In more acute angles, the increase in retention was more obvious. It was also found that an accessory device was necessary to maintain retention capabilities after a long-term use. [source] | ||||||||||