The researchers from Vienna have also noted:
* “NIR spectra were acquired in the wavelength range of 1100-2300nm by means of a transflectance probe for measurements in liquid samples.”
* “For building of regression models a genetic algorithm has been applied for variable selection, and partial least-squares (PLS) regression for creation of linear models.”
* “A realistic estimation of the prediction performance of the models was obtained by a repeated double cross-validation (rdCV).”
* “Reduced data sets with only 15 variables showed improved prediction qualities, in comparison with models containing 235 variables, particularly for the determination of the ethanol concentration in distillation residues (stillages).”
* “The squared correlation coefficient, R(2), between the concentrations obtained by HPLC analysis and the concentrations derived from NIR data (using 15 selected wavelengths, test set samples) was 0.999 for ethanol in stillage, and 0.977 for glucose in mash.”
* “The standard deviation of prediction errors, SEP, obtained from test set samples was 0.6gL(-1) for ethanol (2% of the mean ethanol concentration), and 2.0gL(-1) for glucose (9.6% of the mean glucose concentration).”
5/29/09
5/21/09
Sample cell for hand-held impedance spectroscopy device
Disclosed herein is a sample cell for use in conjunction with an impedance spectroscopy analysis device having two electrodes extending therefrom. The sample cell is attachable to and detachable from the analysis device and includes a housing having an input port for receiving a fluid sample to be tested. The sample cell also includes two spaced apart parallel plates within the housing and in contact with the fluid sample, wherein when the sample cell is attached to the analysis device, each of the two electrodes contacts a respective one of the plates such that an excitation signal can be provided from the analysis device via the electrodes and the plates to excite the fluid sample, and a response signal indicative of the fluid sample can be communicated via the plates and the electrodes to the analysis device.
5/20/09
Portable forensic tool identified for human hair analysis
Analysis of human hair at a crime scene may be possible with a portable technique adapted by Queensland University of Technology researcher Sarina Brandes.
The technique, called Near Infrared Spectroscopy (NIRS), has the advantage of being readily available and Ms Brandes has demonstrated it could be used to analyse hair for forensic purposes.
A chemistry Masters researcher, Ms Brandes said this method was independent of analysis of DNA, which could break down quite quickly, especially at disaster scenes such as after a tsunami.
Her supervisor, Dr Serge Kokot, who has researched the forensic possibilities of human hair analysis for the past 12 years, said human hair could survive relatively harsh environments, where DNA couldn't.
"NIRS has been found to need only a few millimetres of a single hair for analysis, but until now, we have not had the ready capacity to apply this technology in harsh environments," Dr Kokot said.
"Ms Brandes' achievement is several fold: it opens the door for on-field measurements; it provides a method for analysis of hair after immersion in water, and it also has the advantage to readily differentiate a naturally coloured hair from that treated with a hair dye to give a similar colour."
Dr Kokot said Ms Brandes' technique could obtain the infrared profile from only a tiny part of a strand of hair and then interpret this profile using specialised mathematical methods to compare it with similar profiles collected from suitable reference hair samples.
"The results can be displayed in an easily understood diagram and/or the profiles can be rank-ordered and the position of the tested hair can be established relative to the reference samples," he said.
"In this manner, Sarina's technique can establish a person's gender, race and whether they had chemically treated their hair, as well as what the original hair colour was."
Dr Kokot said the use of Ms Brandes' research could help to identify victims of natural disasters, like tsunamis, where hair has been in water.
"Other useful spin-offs have been that Sarina's technique can also identify what type of water the hair was found in, like sea water, and how long the hair had been immersed in it," he said.
"Hair found at a crime scene could be matched against hair found in a comb of the victim which can be used as the reference sample, or it can be compared against hairs from suspects in a similar manner."
Dr Kokot said portable NIRS instruments were available and could be used at a crime or disaster scene.
The technique, called Near Infrared Spectroscopy (NIRS), has the advantage of being readily available and Ms Brandes has demonstrated it could be used to analyse hair for forensic purposes.
A chemistry Masters researcher, Ms Brandes said this method was independent of analysis of DNA, which could break down quite quickly, especially at disaster scenes such as after a tsunami.
Her supervisor, Dr Serge Kokot, who has researched the forensic possibilities of human hair analysis for the past 12 years, said human hair could survive relatively harsh environments, where DNA couldn't.
"NIRS has been found to need only a few millimetres of a single hair for analysis, but until now, we have not had the ready capacity to apply this technology in harsh environments," Dr Kokot said.
"Ms Brandes' achievement is several fold: it opens the door for on-field measurements; it provides a method for analysis of hair after immersion in water, and it also has the advantage to readily differentiate a naturally coloured hair from that treated with a hair dye to give a similar colour."
Dr Kokot said Ms Brandes' technique could obtain the infrared profile from only a tiny part of a strand of hair and then interpret this profile using specialised mathematical methods to compare it with similar profiles collected from suitable reference hair samples.
"The results can be displayed in an easily understood diagram and/or the profiles can be rank-ordered and the position of the tested hair can be established relative to the reference samples," he said.
"In this manner, Sarina's technique can establish a person's gender, race and whether they had chemically treated their hair, as well as what the original hair colour was."
Dr Kokot said the use of Ms Brandes' research could help to identify victims of natural disasters, like tsunamis, where hair has been in water.
"Other useful spin-offs have been that Sarina's technique can also identify what type of water the hair was found in, like sea water, and how long the hair had been immersed in it," he said.
"Hair found at a crime scene could be matched against hair found in a comb of the victim which can be used as the reference sample, or it can be compared against hairs from suspects in a similar manner."
Dr Kokot said portable NIRS instruments were available and could be used at a crime or disaster scene.
5/19/09
5/16/09
4/27/09
Near-Infrared Reflectance Spectroscopy–Principal Components Regression Analyses of Soil Properties
Near-Infrared Reflectance Spectroscopy–Principal Components Regression Analyses of Soil Properties
4/23/09
Application of two-dimensional near-infrared (2D-NIR) correlation spectroscopy to the discrimination of three species of Dendrobium
The objective of this paper was to apply two-dimensional (2D) near-infrared (NIR) correlation spectroscopy to the discrimination of three species of Dendrobium. Generalized 2D-NIR correlation spectroscopy was able to enhance spectral resolution, simplify the spectrum with overlapped bands and provide information about temperature-induced spectral intensity variations that was hard to obtain from one-dimensional NIR spectroscopy. The FT-NIR spectra were measured over a temperature range of 30-140°C. The 2D synchronous and asynchronous spectra showed remarkable differences within the range of 5600-4750 cm-1 between different species of Dendrobium. Copyright © 2009 John Wiley & Sons, Ltd.
4/18/09
4/17/09
4/16/09
4/15/09
Development of a Continuous Online Detecting System for Fruits Using Near Infrared Technology
A continuous online NIR inspection system in cooperation with light source, detection unit, reference calibration unit, and controlling unit was developed for detecting internal quality of a fruit. For the system, the spectrum measurement, reference calibration, and sugar content calculation can be automatically controlled by its operation software which developed with LabVIEW graphical programming language. The developed prototype system was used to measure the sugar content of Waxapples and Jujubes online. As well, the prediction model was established by Pentium III (933M Hz) computer in conveying speed of 40 mm/sec. The detection results demonstrated a good prediction capability from the prediction model. Moreover, the value of R2 is higher than 0.850 and the value of SEC is lower than 0.713, respectively. It indicated that the correct prediction percentage is over 84.4% within ±1 °Brix error. It point out a reliable inspection system specific dealing with the agricultural engineering aspect was developed in this study.
4/14/09
FRUIT QUALITY OF VESUVIAN APRICOTS HARVESTED AT DIFFERENT RIPENING STAGES AFTER A COLD-STORAGE PERIOD
The present study aimed to investigate the influence of a cold-storage period on some qualitative parameters of Vesuvian apricot cultivars using destructive and non-destructive methods. Fruit harvest was performed at three different ripening stages, based on visual evaluations of the ground color of fruit skin. Fruit firmness and soluble solids content (SSC) were measured both destructively and non-destructively (Vis/NIR commercial device). Cultivar-specific sub-models were built using an independent fruit sample at-harvest. The same destructive and non-destructive measurements were also performed on fruit samples after a cold-storage period (7 days at 4°C). The robustness of the models was tested in predicting SSC and firmness of both fruit at-harvest and after the storage. SSC models appeared fairly accurate when used on fruit at-harvest and, in most of the cultivars, also on cold-stored fruit. On the other hand, the accuracy of the SSC models dramatically decreased from fruit at-harvest to cold-stored fruit in some of the tested cultivars. The firmness models had a very poor accuracy when used on both at-harvest and cold-stored fruit. Further researches are needed to improve the accuracy of the firmness models and to build more robust SSC models.
4/13/09
Near Infra Red Diode Array Spectrometers for On-Line Applications - An application paper in the field of agriculture using our LowCost NIR-Spectrom
The introduction of affordable NIR diode array spectrometers now make the measurement of several parameters that are critical to product value readily available. Over the last decade we have seen the introduction of several affordable spectrometers using silicon based sensors, in the 200nm to 1100nm range. This has spawned a host of new applications, including at line/ on line measurements for product quality and process control which were not affordable before. With the introduction of this NIR diode array spectrometer in a similar price range as its visible counterparts, we expect to see similar results. Since the product has just been introduced, not many applications have been developed. Preliminary results by Dr. Arnold Schumann, CREC-UFL show that this spectrometer may be used successfully for the determination of N content (protein) and water in citrus leaves. The spectrometer is currently undergoing application development for use in the corn, soybean and feed industries.
This paper also presents the advantages of NIR diode array technology and highlights the performance characteristics of this affordably priced NIR spectrometer.
This paper also presents the advantages of NIR diode array technology and highlights the performance characteristics of this affordably priced NIR spectrometer.
4/12/09
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