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Curve Approach (curve + approach)
Selected AbstractsReliability analysis of universal joint of a compliant platformFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 7 2010M. M. ZAHEER ABSTRACT The paper describes a methodology for computation of fatigue reliability of universal joint in an articulated offshore tower. Failure criteria were formulated using the conventional Palmgren-Miner rule (S-N curve approach) and the fracture mechanics (F-M) principle. The dynamic analysis of double hinged articulated tower under wind and waves is carried out in time domain. The response histories of hinge shear stresses are employed for the reliability analysis. Advanced first-order reliability method and Monte Carlo simulation method were used to estimate the reliability. Various parametric studies were carried out, which yield important information for the reliability based design. The S-N curve approach yields a significantly conservative estimate of probability of failure when compared to the F-M approach. [source] Air drying of milk droplet under constant and time-dependent conditionsAICHE JOURNAL, Issue 6 2005Xiao Dong Chen Abstract Spray drying is the prime process for many years for manufacturing food powders. Dairy powders are one of the main products consumed worldwide. There has been a stream of studies published previously on both modeling the drying characteristics of a single milk droplet and the dryer wide simulations incorporating computational fluid dynamics (CFD). In CFD simulations, large numbers of particles of different sizes need be tracked to represent the size distribution; it is desirable to have an accurate yet simple model for drying of a single droplet, which does not require partial differential equation. Here for the first time, two such models are validated. One model is of the characteristic drying rate curve approach and the other (new) model is of the reaction engineering approach. The model predictions are compared against a very wide range of experimental results including isothermal and time-varying temperature conditions. © 2005 American Institute of Chemical Engineers AIChE J, 2005 [source] DATA ANALYSIS OF PENETROMETRIC FORCE/DISPLACEMENT CURVES FOR THE CHARACTERIZATION OF WHOLE APPLE FRUITSJOURNAL OF TEXTURE STUDIES, Issue 4 2005C. CAMPS ABSTRACT The objective of the present study was to compare two chemometric approaches for characterizing the rheological properties of fruits from puncture test force/displacement curves. The first approach (parameter approach) computed six texture parameters from the curves, which were supposed to be representative of skin hardness, fruit deformation before skin rupture, flesh firmness and mechanical work needed to penetrate the fruit. The second approach (whole curve approach) used the whole digitized curve (300 data points) in further data processing. Two experimental studies were compared: first, the variability of the rheological parameters of five apple cultivars; second, the rheological variability that was characterized as a function of storage conditions. For both approaches, factorial discriminant analysis was applied to discriminate the fruits based on the measured rheological properties. The qualitative groups in factorial discriminant analysis were either the apple cultivar or the storage conditions (days and temperatures of storage). The tests were carried out using cross-validation procedures, making it possible to compute the number of fruits correctly identified. Thus the percentage of correct identification was 92% and 87% for using the parameter and the whole curve approaches, respectively. The discrimination of storage duration was less accurate for both approaches giving about 50% correct identifications. Comparison of the percentage of correct classifications based on the whole curve and the parameter approaches showed that the six computed parameters gave a good summary of the information present in the curve. The whole curve approach showed that some additional information, not present in the six parameters, may be appropriate for a complete description of the fruit rheology. [source] SEDIMENT TRAPPING WITHIN FORESTRY STREAMSIDE MANAGEMENT ZONES: GEORGIA PIEDMONT, USA,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 6 2004Jason M. Ward ABSTRACT: The effectiveness of streamside management zones (SMZs) was assessed for reducing sediment transport from concentrated overland flow draining two Georgia Piedmont clearcuts that had undergone mechanical and chemical site preparation and planting. Silt fences were used to trap sediment transport from zero-order ephemeral swales at the edge of and within SMZs. Four control swales and nine treatment swales were studied. A double mass curve approach was used to graphically compare sediment accumulation rates at the edge of SMZs to accumulation rates within the SMZs at a distance consistent with current recommendations for SMZ width in Georgia. SMZ efficiencies for trapping sediment transported by concentrated flow ranged from 71 to 99 percent. No statistical model was found to explain how SMZ efficiencies varied with SMZ and contributing area characteristics. Measured sediment accumulations at the SMZ boundary were compared to Revised Universal Soil Loss Equation (RUSLE) predictions of up- slope erosion, and a delivery ratio of 0.25 was calculated. SMZs had a quantifiable and substantial ameliorating effect on sediment transport from concentrated overland flow on the clearcut study sites. [source] Isotactic polypropylene solidification under pressure and high cooling rates.POLYMER ENGINEERING & SCIENCE, Issue 11 2000A master curve approach Solidification in industrial processes very often involves flow fields, high thermal gradients and high pressures: the development of a model able to describe the polymer behavior becomes complex. Recently a new equipment has been developed and improved to study the crystallization of polymers when quenched under pressure. An experimental apparatus based on a modified, special injection moulding machine has been employed. Polymer samples can be cooled at a known cooling rate up to 100°C/s and under a constant pressure up to 40 MPa. Density, Micro Hardness (MH), Wide angle X-ray diffraction (WAXD), and annealing measurements were then used to characterize the obtained sample morphology. Results on one iPP sample display a lower density and a lower density dependence on cooling rate for increasing pressure. Micro hardness confirms the same trend. A deconvolution technique of WAXD patterns is used to evaluate the final phase content of samples and to assess a crystallization kinetics behavior. A master curve approach to explain iPP behavior under pressure and high cooling rates was successfully applied on density results. On the basis of this simple model it is possible to predict the final polymer density by superposition of the effect of cooling rate and the effect of pressure in a wide range of experimental conditions. [source] DATA ANALYSIS OF PENETROMETRIC FORCE/DISPLACEMENT CURVES FOR THE CHARACTERIZATION OF WHOLE APPLE FRUITSJOURNAL OF TEXTURE STUDIES, Issue 4 2005C. CAMPS ABSTRACT The objective of the present study was to compare two chemometric approaches for characterizing the rheological properties of fruits from puncture test force/displacement curves. The first approach (parameter approach) computed six texture parameters from the curves, which were supposed to be representative of skin hardness, fruit deformation before skin rupture, flesh firmness and mechanical work needed to penetrate the fruit. The second approach (whole curve approach) used the whole digitized curve (300 data points) in further data processing. Two experimental studies were compared: first, the variability of the rheological parameters of five apple cultivars; second, the rheological variability that was characterized as a function of storage conditions. For both approaches, factorial discriminant analysis was applied to discriminate the fruits based on the measured rheological properties. The qualitative groups in factorial discriminant analysis were either the apple cultivar or the storage conditions (days and temperatures of storage). The tests were carried out using cross-validation procedures, making it possible to compute the number of fruits correctly identified. Thus the percentage of correct identification was 92% and 87% for using the parameter and the whole curve approaches, respectively. The discrimination of storage duration was less accurate for both approaches giving about 50% correct identifications. Comparison of the percentage of correct classifications based on the whole curve and the parameter approaches showed that the six computed parameters gave a good summary of the information present in the curve. The whole curve approach showed that some additional information, not present in the six parameters, may be appropriate for a complete description of the fruit rheology. [source] | |||||||||||||