scholarly journals Lethality Calculation of Particulate Liquid Foods during Aseptic Processing

Processes ◽  
2019 ◽  
Vol 7 (9) ◽  
pp. 587
Author(s):  
Mohd Tarmizan Ibrahim ◽  
Heiko Briesen ◽  
Petra Först ◽  
Jörg Zacharias
Keyword(s):  
Tube Length ◽  
Tubular Heat Exchanger ◽  
Aseptic Processing ◽  
Simplified Approach ◽  
Transfer Equations ◽  
Model Predictions ◽  
Liquid Foods ◽  
Laminar Pipe Flow ◽  
Good Agreement

In the past two decades, aseptic processing has been implemented in the food industry to sterilize particulate liquid food mixtures. To ensure that particulates in the liquid receive sufficient heating, mathematical modeling is employed to evaluate the temperature and lethality level in the particles. We developed a model for the thermal processing of liquid foods containing cubic particles in a continuous laminar pipe flow system, comprising a tubular heat exchanger. In our simplified approach, heat transfer equations for particulate liquid foods were solved analytically and numerically to evaluate the effect of certain process parameters on the time temperature profiles of particles and the lethality value in the products. A comparison of the particles’ lethality values was made between the experiment and simulation for two different particle residence times in a case study, and the model predictions were in good agreement with experimental data. Based on modeling studies, it was found that within the range of parameters studied, an increase in flow rate and particle size resulted in a decrease in the lethality value of the particles, while an increase in particle concentration and holding tube length resulted in the opposite effect.

Structural Analysis of an Offshore Jacket Model Under Seismic Excitation

2008 ◽  
Author(s):  
Helder J. D. Correia ◽  
Anto´nio C. Mendes ◽  
Carlos A. F. S. Oliveira
Keyword(s):  
Point Of View ◽  
Shaking Table ◽  
Seismic Excitation ◽  
Model Structure ◽  
Structural Members ◽  
Jacket Structures ◽  
Reaction Forces ◽  
Nodal Displacements ◽  
Good Agreement

In the present work the action of earthquakes upon offshore jacket structures is analysed by means of ADINA software. Our case-study refers to an existing model structure, previously constructed at the Laboratory of Fluid Mechanics of UBI, which has been analysed from the hydrodynamic point of view — Mendes et al. [1, 2]. The seismic excitation will be imposed at the base of this model structure, with frequencies and amplitudes corresponding to actual earthquake conditions transposed to the model scale of 1:45. The FEM software is utilised to calculate the natural frequencies of the model and to obtain stresses at selected members, as well as their nodal displacements. Our purpose is to quantify maximum stresses occurring in critical structural members and to verify the survivability criterion. The predictions of the numerical model, in terms of the reaction forces at the base and acceleration at the top of the structure, are then correlated with the experimental measurements performed when the model structure is excited in an especially designed shaking table (Correia [3]), revealing a good agreement between both results.

Rigid-Plastic Impact of Single Angular Particles

2021 ◽  
Author(s):  
Sandeep Dhar
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Orientation Dependence ◽  
Particle Orientation ◽  
Rigid Plastic ◽  
Plastic Model ◽  
Model Predictions ◽  
Good Agreement ◽  
Angular Particles

The trajectory of an angular particle as it cuts a ductile target is, in general, complicated because of its dependence not only on particle shape, but also on particle orientation at the initial instant of impact. This orientation dependence has also made experimental measurement of impact parameters of single angular particles very difficult, resulting in a relatively small amount of available experimental data in the literature. The current work is focused on obtaining measurements of particle kinematics for comparison to rigid plastic model developed by Papini and Spelt. Fundamental mechanisms of material removal are identified, and measurements of rebound parameters and corresponding crater dimensions of single hardened steel particles launched against flat aluminium alloy targets are presented. Also a 2-D finite element model is developed and a dynamic analysis is performed to predict the erosion mechanism. Overall, a good agreement was found among the experimental results, rigid-plastic model predictions and finite element model predictions.

Viscosity Models Based on Network Theory for Polymer Melts

2010 ◽  
Vol 129-131 ◽  
pp. 1244-1247
Author(s):  
Hai Hang Xu ◽  
Lei Zhong
Keyword(s):  
Experimental Data ◽  
Kinetic Equation ◽  
Constitutive Equation ◽  
Polymer Composites ◽  
Network Theory ◽  
Polymer Melts ◽  
Structure Parameter ◽  
Viscosity Models ◽  
Model Predictions ◽  
Good Agreement

New shear and extensional viscosity models based on Fredrickson kinetic equation coupled with Dewitt constitutive equation were established to predict viscosities of polymer melts. The experimental data of 125°C LDPE and LDPE filled with 35% glass beads reported from references were compared with the model predictions. The predictions showed good agreement with the measurements. The models are simple and easy to use. Because they contain no structure parameter, they are capable to describe the viscosities of pure polymer and polymer composites.

Defining soil macrofauna composition and activity for biopedological studies - A case study on two soils in the Western Australian wheat belt

Soil Research ◽  
1993 ◽  
Vol 31 (1) ◽  
pp. 83 ◽  
Author(s):  
LAL Debruyn
Keyword(s):  
Substantial Contribution ◽  
Resident Species ◽  
Pitfall Trapping ◽  
Soil Macrofauna ◽  
Major Species ◽  
Australian Wheat ◽  
Species Mapping ◽  
Western Australian ◽  
Good Agreement

In Durokoppin reserve and surrounding farmland, part of the central wheatbelt region, pitfall trapping and mapping of soil macrofauna activity were used to define the extent of soil macrofauna activity in these two environments. This type of study is a necessary precursor to determining the significance of certain invertebrate activity in soil modification in these habitats. The relative merits of the two techniques in determining the extent of soil macrofauna activity is assessed. The soil macrofauna groups identified by mapping and pitfall trapping as making a substantial contribution (in terms of relative abundance and activity) in all habitats were, in descending order, ants, spiders and scorpions (wandoo woodland only). In general there was good agreement between the two techniques in identifying the major species and trends in species composition between habitats, but mapping failed to identify the rare or cryptic species. Mapping more accurately identified the resident species in each habitat compared with pitfall trapping. Pitfall trapping data indicated that foraging activity of most soil macrofauna was depressed over winter, except for beetles, and was higher in the spring and summer sampling periods. However, mapping revealed a more constant level of soil macrofauna activity, especially for ant nests. It is argued that the two approaches complement one another and that each has value in interpreting the effects of soil macrofauna activity on soil properties in further studies. The discussion is based on the results of a study carried out in the Kellerberrin area of Western Australia.

Modeling the Effect of Water Activity, pH, and Temperature on the Probability of Enterotoxin A Production by Staphylococcus aureus

2016 ◽  
Vol 79 (1) ◽  
pp. 148-152 ◽  
Author(s):  
TIAN DING ◽  
YAN-YAN YU ◽  
CHENG-AN HWANG ◽  
QING-LI DONG ◽  
SHI-GUO CHEN ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Water Activity ◽  
Storage Temperature ◽  
Probability Model ◽  
Toxin Production ◽  
Factors Affecting ◽  
Model Predictions ◽  
And Storage ◽  
Storage Temperatures ◽  
Good Agreement

ABSTRACT The objectives of this study were to develop a probability model of Staphylococcus aureus enterotoxin A (SEA) production as affected by water activity (aw), pH, and temperature in broth and assess its applicability for milk. The probability of SEA production was assessed in tryptic soy broth using 24 combinations of aw (0.86 to 0.99), pH (5.0 to 7.0), and storage temperature (10 to 30°C). The observed probabilities were fitted with a logistic regression to develop a probability model. The model had a concordant value of 97.5% and concordant index of 0.98, indicating that the model satisfactorily describes the probability of SEA production. The model showed that aw, pH, and temperature were significant factors affecting the probability of toxin production. The model predictions were in good agreement with the observed values obtained from milk. The model may help manufacturers in selecting product pH and aw and storage temperatures to prevent SEA production.

A Study of Abrasive Jet Micro-Grooving of Quartz Crystals

2010 ◽  
Vol 443 ◽  
pp. 645-651 ◽  
Author(s):  
Alireza Moridi ◽  
Jun Wang ◽  
Yasser M. Ali ◽  
Philip Mathew ◽  
Xiao Ping Li
Keyword(s):  
Predictive Models ◽  
Deep Understanding ◽  
Machining Process ◽  
Micro Machining ◽  
Machining Performance ◽  
Quartz Crystals ◽  
Abrasive Jet Machining ◽  
Model Predictions ◽  
Micro Grooving ◽  
Good Agreement

Owing to its various distinct advantages over the other machining technologies, abrasive jet machining has become a promising machining technology for brittle and hard-to-machine materials. An experimental study is presented on the micro-grooving of quartz crystals using an abrasive airjet. The effect of the various process parameters on the major machining performance measures are analysed to provide a deep understanding of this micro-machining process. Predictive models are then developed for quantitatively estimating the machining performance. The models are finally verified by an experiment. It shows that the model predictions are in good agreement with the experimental results under the corresponding conditions.

A Control Strategy and Upper Bound Solution for Non-Flat Tool Open Die Forging Automation

1999 ◽  
Author(s):  
T. J. Nye
Keyword(s):  
Control Strategy ◽  
Upper Bound ◽  
Sequence Generation ◽  
Bound Solution ◽  
Upper Bound Solution ◽  
Die Forging ◽  
Strategy Model ◽  
Model Predictions ◽  
Open Die Forging ◽  
Good Agreement

Abstract The open die forging process can provide a number of benefits if its costs can be made competitive through automation. This paper describes a control strategy for automated open die forging forming sequence generation. An upper bound solution for forging with radiused tools is developed, along with a method for using this solution to estimate forming results, a necessary component of the control strategy. Model predictions are compared to physical experimental data using plasticine, and show good agreement.

scholarly journals Structural Redundancy Assessment of Adjacent Precast Concrete Box-Beam Bridges in Service

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Yanling Leng ◽  
Jinquan Zhang ◽  
Ruinian Jiang ◽  
Yangjian Xiao
Keyword(s):  
Precast Concrete ◽  
Fe Analysis ◽  
Load Testing ◽  
Structural Redundancy ◽  
Simplified Approach ◽  
Box Beam ◽  
Nonlinear Fe Analysis ◽  
Redundancy Level ◽  
Real Behavior

Present approaches for assessing bridge redundancy are mainly based on nonlinear finite element (FE) analysis. Unfortunately, the real behavior of bridges in the nonlinear range is difficult to evaluate and a sound basis for the nonlinear FE analysis is not available. In addition, a nonlinear FE analysis is not feasible for practitioners to use. To tackle this problem, a new simplified approach based on linear FE analysis and field load testing is introduced in this paper to address the particular structural feature and topology of adjacent precast concrete box-beam bridges for the assessment of structural redundancy. The approach was first experimentally analyzed on a model bridge and then validated by a case study. The approach agrees well with the existing recognized method while reducing the computation complexity and improving the reliability. The analysis reveals that the level of redundancy of the bridge in the case study does not meet the recommended standard, indicating that the system factor recommended by the current bridge evaluation code for this bridge is inappropriate if considering the field condition. Further research on the redundancy level of this type of bridges is consequently recommended.

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