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A szabadföldi trágyázási (tartam)kísérletek eredményeit talaj-, illetve diagnosztikai célú növényvizsgálatok segítségével tudjuk kiterjeszteni, általánosítani – figyelembe véve természetesen a kiterjesztés korlátait is. Célszerűnek láttuk ezen túl a talaj könnyen oldható tápelem-, közöttük P-tartalmát is meghatározni a hazánkban hivatalosan elfogadott AL- (ammónium-laktátos) módszer mellett az Európai Unióban és Észak-Amerikában alkalmazott P-tesztekkel is (CaCl2-, H2O-, Olsen-, Bray1-, LE-, Mehlich3- stb.) a hazai OMTK kísérletek talajmintáiban. A kísérleti helyek talajtulajdonságaiban megnyilvánuló jelentős különbségek lehetőséget adnak rá, hogy a talaj P-teszteket – és a növényi P-felvételt – jellegzetes hazai talajokon, sokszor szélsőséges talajparaméterek mellett vizsgáljuk. Az egyes P-szintek között a 28 év átlagában mintegy évi 50 kg P2O5·ha-1 volt a különbség. A P0-szinten mért P-tartalmak jól jelezték az egyes kísérleti helyek talajának eltérő P-ellátottságát, illetve, közvetve, fizikai féleségében, pH és mészállapotában meglévő különbségeket. A P2-szinten – a hazai talajokra, P-igényes növényekre a hazai szabadföldi P-trágyázási tartamkísérleti adatbázisban talált összefüggésekre alapozott – új AL-P határértékek szerint csupán a bicsérdi csernozjom barna erdőtalajon nem javult a P-ellátottság legalább a „jó” szintig. Vizsgálataink megerősítették az AL-módszer függőségét a CaCO3-tartalomtól: a Mehlich3 módszerrel való összefüggésben a karbonátmentes és a karbonátos talajok csoportja erőteljesen elkülönült egymástól. Az AL-P korrekció elvégzése, azaz az AL-P értékeknek egy standard talajtulajdonság-sorra való konvertálása (KA: 36; pH(KCl): 6,8; CaCO3: 0,1%) látványosan csökkentette az AL-módszernek a talaj CaCO3-tartalmától való függőségét. Az AL-P és Olsen-P, valamint a korrigált AL-P és Olsen-P tartalmak összehasonlításában ugynakkor ugyanez az összefüggés nem volt állapítható, ami arra utal, hogy az Olsen módszer bizonyos fokig szintén pH- és mészállapot függő. Kísérleti eredményeink megerősítették a Sarkadi-féle AL-P korrekciós modell helytálló voltát. Fenti megállapításunkat ugyanakkor a növényi P-tartalmakkal való összefüggéseknek is igazolniuk kell. Szükséges tehát a talajvizsgálati eredményeknek a diagnosztikai célú növényvizsgálatokkal, valamint a terméseredményekkel való összevetése. A tartamkísérletek talajai lehetőséget nyújtanak a környezetvédelmi célú P-vizsgálatok értékelésére, a talaj P-feltöltöttsége környezeti kockázatának becslésére. Ezekkel a kérdésekkel a cikksorozat további részeiben kívánunk foglalkozni.

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. 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 . [22

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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

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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. p -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 2 =0.927; 1-VR=0.786. Weak relationship was found for PV (R 2 =0.48) and CON (R 2 =0.109). For pAV, good calibration was gained, expressly below 200 °C, in the 2000–2500 nm wavelength interval (R 2 =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 p -anisidine value of lard below 200 °C.

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Acta Alimentaria
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.

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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

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Pollack Periodica
Authors: David Honek, Zuzana Németová, Silvia Kohnová, and Monika Šulc Michalková

Abstract

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.

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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.

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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.

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Acta Alimentaria
Authors: J. Gajdoš Kljusurić, S. Djaković, I. Kruhak, K. Kovačević Ganić, D. Komes, and Ž. Kurtanjek

Briggs-Rauscher (BR) reaction is one of the most commonly studied oscillation reactions that has been applied for measurement of antioxidant activity of water-soluble substances. There is an immediate quenching of oscillations when free radicals are added from fruits or vegetables. The reaction is monitored potentiometrically and the inhibition time (IT), or time of no oscillations, is proportional to the concentration of antioxidants. pH of the BR reaction is about 2, which is similar to that of the fluids of the main digestive process (human stomach), giving in vitro information on antioxidant activity under “real digestion conditions”and can help in assessment of nutrition for the maintenance of health and prevention of diseases. Antioxidant activities of different concentrations of native Croatian red and white wines are analysed by the inhibition of BR reaction and determination of total phenols using gallic acid as the calibration standard is also carried out. Using mathematical models, relative antioxidant activities of antioxidants and amounts of total phenols are estimated. Second order polynomial calibration curve is estimated in the range of 150-2500 gallic acid equivalent (GAE mg l-1), with standard error of 84 GAE mg l-1.

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