Spectrometer Research Papers - Academia.edu (original) (raw)

Saturn has been a source of interest and fascination for centuries. Besides its rings, one of the most spectacular planetary features seen in the solar system, Saturn has several moons that present a potential habitable environment.... more

Saturn has been a source of interest and fascination for centuries. Besides its rings, one of the most spectacular planetary features seen in the solar system, Saturn has several moons that present a potential habitable environment. Some of these moons have liquid water or an impressive atmosphere worth studying in-depth. This particular interest in Saturn led to a mission conducted by the biggest interplanetary unmanned probe ever built: the Cassini-Huygens mission. Once inserted into Saturn’s orbit in 2004, the scientific instruments on board Cassini, particularly the Composite Infrared Spectrometer (CIRS), have collected an impressive amount of data leading to many new scientific discoveries. The only other mission to ever study Saturn was Voyager. Equipped with the Infrared Interferometer Spectrometer and Radiometer (IRIS), considered a state of the art instrument in the seventies, Voyager was able to collect fascinating but insufficient data about Saturn. Cassini’s role was to perform an in-depth study based on the data collected by Voyager. This study is a comparison between the results of the two spectrometers, with the purpose to demonstrate that the Cassini spectrometer generated much more data and results than the Voyager spectrometer.

Leaf Area Index (LAI) is an important variable that governs canopy processes and can be monitored by satellites. The current study aims at exploring the potential and limitations of using the red-edge spectral bands of the forthcoming... more

Leaf Area Index (LAI) is an important variable that governs canopy processes and can be monitored by satellites. The current study aims at exploring the potential and limitations of using the red-edge spectral bands of the forthcoming superspectral satellites, namely—Vegetation and Environmental New micro Spacecraft (VENμS) and Sentinel-2, for assessing LAI in field crops. The research was conducted in experimental plots of wheat and potato in the northwestern Negev, Israel. Continuous spectral data were collected by a field spectrometer and LAI data were obtained by a ceptometer. The spectral data were resampled to the superspectral VENμS and Sentinel-2 resolutions. The data were divided into seven datasets (four seasons, two crops, and one including all data). The LAI prediction abilities by Partial Least Squares (PLS) models for continuous spectra and the resampled spectra were compared and evaluated. For wheat and potato of the continuous, VENμS, and Sentinel-2 data formations, the PLS correlation coefficients (r) values were 0.93, 0.93, and 0.92, respectively. In most cases, the red-edge region was found to be the most important spectral region for the three data formations, according to the Variable Importance in Projection (VIP) analysis. Additionally, Normalized Difference Vegetation Index (NDVI) and the Red-Edge Inflection Point (REIP) were computed for the three data formations in order to observe relation to as well as prediction accuracy in retrieving LAI values. The prediction abilities of the calculated indices by the data formations were compared, peaking for wheat, with r values of 0.91 for the REIP for the three data formations. Therefore, it is concluded that VENμS and Sentinel-2 can spectrally assess LAI as good as a hyperspectral sensor. The REIP was found to be a significantly better predictor than NDVI for wheat data and therefore can potentially be implemented for future LAI monitoring applications by superspectral sensors that contain four red-edge bands.► Superspectral band settings can predict LAI as good as continuous spectra. ► REIP can predict LAI for relatively high biomass and fractional cover crops. ► On ground level, REIP is a better LAI predictor for wheat than for potato.

We present a clinical investigation of diffuse reflectance and time-resolved autofluorescence spectra of skin cancer with an emphasis on basal cell carcinoma. A total of 25 patients were measured using a compact steady-state diffuse... more

We present a clinical investigation of diffuse reflectance and time-resolved autofluorescence spectra of skin cancer with an emphasis on basal cell carcinoma. A total of 25 patients were measured using a compact steady-state diffuse reflectance/fluorescence spectrometer and a fibre-optic-coupled multispectral time-resolved spectrofluorometer. Measurements were performed in vivo prior to surgical excision of the investigated region. Singular value decomposition was used to reduce the dimensionality of steady state diffuse reflectance and fluorescence spectra. Linear discriminant analysis was then applied to the measurements of basal cell carcinomas (BCCs) and used to predict the tissue disease state with a leave-one-out methodology. This approach was able to correctly diagnose 87% of the BCCs. With 445 nm excitation a decrease in the spectrally averaged fluorescence lifetime was observed between normal tissue and BCC lesions with a mean value of 886 ps. Furthermore, the fluorescence ...

Broadband sensing and spectroscopy in millimeter-wave and subterahertz frequencies can be facilitated with CMOS coherent detectors as a low-power, low-cost solution. This paper presents a fully integrated coherent detector with a... more

Broadband sensing and spectroscopy in millimeter-wave and subterahertz frequencies can be facilitated with CMOS coherent detectors as a low-power, low-cost solution. This paper presents a fully integrated coherent detector with a broadband frequency comb as an on-chip reference signal. The receiver incorporates a frequency comb generator, which provides a broadband comb as a reference for heterodyne detection, and an NMOS field-effect transistor as the heterodyne detector. It also includes an on-chip elliptical antenna with a periodic structure which enhances its directivity up to +10 dBi without using a lens. The receiver detects any arbitrary spectrum from 50 GHz to 280 GHz with resolution of 2 Hz by tuning the comb spacing of the reference signal from 100 MHz to 5 GHz. The chip is implemented in a standard 65-nm CMOS process and it consumes 34 mW dc power.

Clinoptilolite, a type of natural zeolite, has been commonly used as pozzolanic additive in concrete. This type of natural zeolite is generally used as a mineral admixture by substitution in Portland cement to produce high performance... more

Clinoptilolite, a type of natural zeolite, has been commonly used as pozzolanic additive in concrete. This type of natural zeolite is generally used as a mineral admixture by substitution in Portland cement to produce high performance concretes. In the present study, the major, minor and trace element levels present in the clinoptilolite-rich natural zeolite (CRNZ) have been determined using a wavelength dispersive X-ray fluorescence spectrometer. Also, the clinoptilolite-rich natural zeolite has been compared with Portland cement with respect to the radiation attenuation properties. From the results it can be concluded that due to the natural radioactive content of clinoptilolite-rich natural zeolite (CRNZ) even if it is in trace level and also due to the poorer X-ray attenuation compared with Portland cement, special care should be taken to use this type of natural zeolite as blend materials in cements, etc.

Over the past several years, the demand for high quality agricultural products has been remarkably increased. Thus, it is important to use non-destructive methods for product quality monitoring. LED-induced fluorescence spectroscopy has... more

Over the past several years, the demand for high quality agricultural products has been remarkably increased. Thus, it is important to use non-destructive methods for product quality monitoring. LED-induced fluorescence spectroscopy has proved its potential for non-destructive detection of some defects in agricultural products, such as tissue browning and bruising. Due to such defects, changes in the polyphenol and chlorophyll contents occur which can be considered as the visible marks of decreasing fruit quality. In the present work, a fluorescence spectrometer (spectrofluorometer) controlled by LabVIEW software was designed and developed. In this spectrometer, a consumer-grade webcam was used as an imaging sensor. The spectrometer was able to measure the fluorescence spectra directly from the fruit and vegetable surface in the desired regions. To do so, the spectrometer was equipped with a suitable fiber-optic probe. The hardware solution was based on data acquisition working on the USB platform and controlled by the application running on the PC. In this system, light emitting diodes with different wavelengths were used as the excitation sources for inducing fluorescence spectra of some famous fruits and vegetables.

Mass-Spectrometry (MS) based biological analysis is a powerful approach for discovering novel biomarkers or identifying patterns and associations in biological samples. Each value of a spectrum is composed of two measurements, m/Z (mass... more

Mass-Spectrometry (MS) based biological analysis is a powerful approach for discovering novel biomarkers or identifying patterns and associations in biological samples. Each value of a spectrum is composed of two measurements, m/Z (mass to charge ratio) and intensity. Even if data produced by mass spectrometers contains potentially huge amount of information, data are often affected by errors and noise due

UV–vis photodissociation action spectroscopy is becoming increasingly prevalent because of advances in, and commercial availability of, ion trapping technologies and tunable laser sources. This study outlines in detail an instrumental... more

UV–vis photodissociation action spectroscopy is becoming increasingly prevalent because of advances in, and commercial availability of, ion trapping technologies and tunable laser sources. This study outlines in detail an instrumental arrangement, combining a commercial ion-trap mass spectrometer and tunable nanosecond pulsed laser source, for performing fully automated photodissociation action spectroscopy on gas-phase ions. The components of the instrumentation are outlined, including the optical and electronic interfacing, in addition to the control software for automating the experiment and performing online analysis of the spectra. To demonstrate the utility of this ensemble, the photodissociation action spectra of 4-chloroanilinium, 4-bromoanilinium, and 4-iodoanilinium cations are presented and discussed. Multiple photoproducts are detected in each case and the photoproduct yields are followed as a function of laser wavelength. It is shown that the wavelength-dependent partitioning of the halide loss, H loss, and NH3 loss channels can be broadly rationalized in terms of the relative carbon-halide bond dissociation energies and processes of energy redistribution. The photodissociation action spectrum of (phenyl)Ag2+ is compared with a literature spectrum as a further benchmark. Figure ᅟ

PRISMA (PRecursore IperSpettrale della Missione Applicativa) hyperspectral instrument is an advanced hyperspectral sensor including a panchromatic camera at medium resolution. The instrument is the focus of the new Earth observation... more

PRISMA (PRecursore IperSpettrale della Missione Applicativa) hyperspectral instrument is an advanced hyperspectral sensor including a panchromatic camera at medium resolution. The instrument is the focus of the new Earth observation mission that a consortium of Italian companies has started developing under contract of Italian Space Agency. Key features of the instrument are the very high requirement for signal-to-noise and the

Abstract—This paper presents a statistical study for rubber seed clones classification. There are five types of clones from the same series of rubber seed being used as samples in this work which are the PB360, RRIM2009, RRIM2011,... more

Abstract—This paper presents a statistical study for rubber seed clones classification. There are five types of clones from the same series of rubber seed being used as samples in this work which are the PB360, RRIM2009, RRIM2011, RRIM2016 and RRIM2025. The main ...