Authors:A. Păucean, D.C. Vodnar, V. Mureșan, F. Fetea, F. Ranga, S.M. Man, S. Muste, and C. Socaciu
, F. , He , Y. , Wang , L. & Sun , G. ( 2011 ): Detection of organic acids and pH of fruit vinegars using near-infrared spectroscopy and multivariate calibration . Food Bioprocess Tech. , 4 , 1331 – 1340
Calibration of a catchment-based land surface model in the Loire River basin (France) to assess hydrological impacts of climate change, Master Thesis , Environmental Engineering, Technische Universitat Munchen , 2009 .
Authors:Ü.İ. Konak, H.A. Yatmaz, Ş. Nilüfer, T. Erkaymaz, and M. Certel
from 27 samples. The linearity was evaluated by using six calibration points (0, 10, 25, 50, 75, and 100 μg kg −1 ) in the range of 0–100 μg kg −1 . Peak area was selected as response and a coefficient of determination ( r 2 ) higher than 0.995 was
Authors:A. Szabó, G. B’azár, G. Andrássy-Baka, L. Locsmándi, and R. Romvári
Lard is a preferred frying fat in the Hungarian culinary routine. Our study aimed at measuring conventional fat quality indices and performing NIR-based calibrations of those indices, during prolonged heating. Lard was heated for 4 days at 8 different temperatures (160, 170, 175, 180, 185, 190, 200 and 230 °C) for 8 h a day (n=32+1, i.e. the original sample). Acid value (AV) and carbonyl value (CON) increased in parallel with the duration of heating and heating intensity. Peroxide value (PV) increased in the first 8 h, and decreased back during further treatment.
-Anisidine value (pAV) increased at each heating temperature below 200 °C, while temperatures above 200 °C decreased it. NIR analysis (NIRSystems 6500) was performed on original samples in transflectance mode (400–2500 nm wavelength range, 0.1 mm layer thickness, aluminium-plated reflector). Treatment characteristics (temperature, heat-sum, sampling event) could be estimated effectively. Calibration for AV was robust: R
=0.927; 1-VR=0.786. Weak relationship was found for PV (R
=0.48) and CON (R
=0.109). For pAV, good calibration was gained, expressly below 200 °C, in the 2000–2500 nm wavelength interval (R
=0.912; 1-VR=0.772). Based on calibration and cross-validation results, NIR technique may be a rapid, solvent-free alternative for the estimation of acid value and
-anisidine value of lard below 200 °C.
Authors:M. Gyalai-Korpos, A. Fehér, Zs. Barta, and K. Réczey
The need to introduce promising bioethanol production technologies calls for advanced laboratory techniques to study experiment designs and to obtain their results in a quick and reliable way. Real time monitoring based on general principles of ethanol fermentation, such as effluent CO2 volume, avoids time consuming steps, long lasting analyses and delivers information about the process directly. A device based on the above features and capable for real time monitoring on parallel channels was developed by the authors and is described in this paper. Both for calibration and for fermentation, test runs were carried out on different days and channels. Statistical evaluation was based on the obtained data. According to the t-test (P=0.05) and Grubbs analysis, the calibration method is reliable regardless of the date of calibration. When evaluating the fermentation results by ANCOVA acceptable standard derivations were obtained as impact of channel (58.8 ml), date (82.1 ml) and incorporating all impacts (116.2 ml). The final ethanol concentrations calculated based on the gas volume were compared to ones determined by HPLC and an average difference of 10% was found. Thus, the device proved to be advantageous in monitoring fermentation.
Authors:E. Dadáková, N. Vrchotová, Š. Chmelová, and B. Šerá
Standard (1994a): Water quality-calibration and evaluation of analytical methods and estimation of performance characteristics . Part 1: Statistical evaluation of the linear calibration function. Czech Standards Institute, Praha, ČSN-ISO 8466-1, 15 pages
Authors:Adina Vătăman, Adrian Ciutina, and Daniel Grecea
Eccentrically braced frames are well known for their capacity of dissipating seismic energy by plastic hinge formation in the so called ‘link elements’, which represent the dissipative devices of the eccentrically braced frame. The link element can be short, which means it will be mainly subjected to shear forces; long being mainly subjected to bending moment or intermediate in length subjected to a combined action of shear force-bending moment. The current study is focused on the calibration of existing experimental results with numerical finite element models of steel eccentrically braced frames with short link elements and a subsequent parametrical study considering different link lengths and multiple stiffeners along the link web panel.
Authors:David Honek, Zuzana Németová, Silvia Kohnová, and Monika Šulc Michalková
The modeling of soil erosion processes is affected by several factors that reflect the physical-geographic conditions of the study site together with the land use linkage. The soil parameters are significant in the modeling of erosion and also runoff processes. The correct determination of a soil's parameters becomes a crucial part of the model's calibration. This paper deals with a sensitivity analysis of seven soil input parameters to the physically-based Erosion 3D model. The results show the variable influence of each soil parameter. The Erosion 3D model is very sensitive to initial soil moisture, bulk density, and erodibility.
Authors:Zbyšek Pavlík, Lukáš Fiala, and Robert Černý
The moisture content in materials has influence on their thermal, acoustic and mechanical properties, what has clear relation to their durability and service life. On this account, there is necessary to monitor liquid moisture content in building materials, and to know its influence on their behavior and performance. This information can find use already in the design of building structures as well in the restoration and reconstruction of existing buildings.In the presented paper, the problem of calibration of high frequency time domain reflectometry (TDR) method for moisture content measurement in porous building materials is studied. In this work there is focused on analysis of dielectric mixing models that can be used for calibration of dielectric moisture measurement methods. Experimentally accessed data were compared with the results of several mixing dielectric models like formulas developed by de Loor, Dobson, Polder and van Santen and Lichtenecker as well as Wiener’s and Hashin-Shtrikman’s bounds, which define a theoretical minimal and maximal value of permittivity for the given moisture content.On the basis of performed experiments and calculations, the suitable mixing models are identified and recommendations for their practical application are formulated.
In the industrial practice Howard mould count (Howard, 1911) is used for the estimation of mould contamination of foods. It was developed originally for the investigation of mould contamination of tomato purée. It is also used nowadays for quality control purposes for other food products as well. Recently this constitutes the basis of the acceptance of the finished products in international trade. This technique demands experts with a lot of practice and morphological proficiency. The investigation makes use of eyes and so the tiredness of the investigator can cause uncertainties.The possibility of other methods for the determination of mould contamination of tomato purée was investigated to replace the Howard method. The NIR technique — as a rapid, non-destructive, reagentless and accurate method — was anticipated as a suitable method for the mentioned purpose. Canned tomato purée had been allowed to become mouldy then the sample was blended with non-mouldy samples in different ratio, so a series of tomato purées containing known amounts of mouldy purée was prepared. Howard mould counts and ergosterol content — another mould contamination relating value — was used as reference for NIR calibration.At quantitative investigation better results were obtained using ergosterol values. The best correlation coefficient (R=0.93) and the smallest standard error of calibration (SEC=0.008 mg g−1 ergosterol) was achieved with triangular smoothing and second derivation of the spectra. At qualitative investigation Polar Qualification System (PQS) was used. Clusters between samples with low and high ergosterol levels could be separated.