Investigation of Volatiles in Cork Samples Using Chromatographic Data and the Superposing Significant Interaction Rules (SSIR) Chemometric Tool

This study describes a new chemometric tool for the identification of relevant volatile compounds in cork by untargeted headspace solid phase microextraction and gas chromatography mass spectrometry (HS-SPME/GC-MS) analysis. The production process in cork industries commonly includes a washing procedure based on water and temperature cycles in order to reduce off-flavors and decrease the amount of trichloroanisole (TCA) in cork samples. The treatment has been demonstrated to be effective for the designed purpose, but chemical changes in the volatile fraction of the cork sample are produced, which need to be further investigated through the chemometric examination of data obtained from the headspace. Ordinary principal component analysis (PCA) based on the numerical description provided by the chromatographic area of several target compounds was inconclusive. This led us to consider a new tool, which is presented here for the first time for an application in the chromatographic field. The superposing significant interaction rules (SSIR) method is a variable selector which directly analyses the raw internal data coming from the spectrophotometer software and, combined with PCA and discriminant analysis, has been able to separate a group of 56 cork samples into two groups: treated and non-treated. This procedure revealed the presence of two compounds, furfural and 5-methylfurfural, which are increased in the case of treated samples. These compounds explain the sweet notes found in the sensory evaluation of the treated corks. The model that is obtained is robust; the overall sensitivity and specificity are 96% and 100%, respectively. Furthermore, a leave-one-out cross-validation calculation revealed that all of the samples can be correctly classified one at a time if three or more PCA descriptors are considered.

Development and Validation of VVER-1000 Thermohydraulic Computer Model for TRACE Computer Code

The basic features of the development process, results of validation and their analysis are presented in the paper. VVER 1000/V-320 thermohydraulic model for TRACE computer code was developed. Validation calculation with this model was performed to confirm that this model is capable of simulating VVER 1000/V-320 nuclear power plant response during transients and accidents. At the initial step of TRACE thermohydraulic model validation for VVER 1000/V-320, the initial and boundary conditions corresponding to the transient being evaluated were incorporated into the model and preliminary calculation was performed. The calculation results were compared with plant instrumentation data. The following representative transients for which detailed plant instrumentation records are available were selected for validation calculation is “Rivne NPP (RNPP) Unit 3 pressurizer pilot operated relief valve (PORV) stuck in open position during scheduled tests”. An experience that has been obtained, expanded opportunities of the SSTC NRS to use modern codes in the scientific and technical support of NRC.

Porous Media Approach of a CFD Code to Analyze Thermal Hydraulics of PWR Components

This paper presents a set of numerical procedure to innovate CFD code into a PWR component analysis code. A porous media approach is adapted to two-fluid model and conductor model, and a pack of constitutive relations close the numerical model into a PWR component analysis code. The separate verification calculations on conductor model and porous media approach, and the validation calculation for the integrated component-scale code are introduced.