Optimal Measurement Conditions Research Articles

Bounds and Conditions for Compressive Digital Holography Using Wavelet Sparsifying Bases

Numerous experiments have been conducted with success in the field of compressive digital holography, but the theory to determine optimal measurement conditions is lagging behind. In contrast to a prior study that expects object wavefields to be sparse in the spatial domain, we investigate how the configuration of the interferometer influences the reconstruction of wavefields that are sparse in a multiresolution orthogonal wavelet basis. In particular, we derive expressions for the coherence between the free-space wave propagation operator and the basis functions of a Shannon multiresolution representation as a function of the wavelength, the propagation distance, the image sensor's pixel pitch, and the scale of the basis functions. These expressions reveal that the coherence as a function of the Fresnel number is subject to specific scaling and translating rules as the scale of the basis functions changes. For a multiresolution orthogonal wavelet representation and digital holograms that are recorded in the near field, we deduce subsequently the optimal configuration of the interferometer and we show by means of hypothesis testing that the associated phase transition bound coincides with the weak threshold for block-sparse compressive sensing with a block length of 2, which is an optimal bound for the class of complex-valued compressive sensing problems. By means of experiments with a USAF 1951 resolution target and an angle grid, we validate our findings and demonstrate that the reconstructed object wavefields are resilient to sparsity defects and additive noise.

THE IMPACT OF THE SEA WATER FREEZING PHENOMENON ON MILITARY OPERATIONS ON THE ROMANIA’S BLACK SEA’S SHORE

The purpose of this paper is to emphasize the importance of studying the ice regime at the Black Sea, as there are not many studies made on the Black Sea’s water freezing phenomena. Based on the few studies made in this domain, which include meteorological data analysis, satellite images of the main parameters which determine the optimal conditions for sea ice formation, periodic measurements and observations of the ice evolution along the past decades, we have analyzed their results and drawn some conclusions regarded to the negative influence of these rare but very important phenomena on the main military activities executed on the Romania’s Black Sea’s shore by different naval, air and special units forces.

Proton radiography and computed tomography with dynamic water range shifter

We introduce a novel dynamic water range shifter (DWRS) that enables range shifting of a mono-energetic proton beam for the purpose of obtaining a water equivalent path length (WEPL). A scintillation screen and a charge-coupled device (CCD) camera were assembled with a mirror for a detecting system. We acquired two sets of proton radiographs with and without the scanned object, and calculated 2D distribution of the WEPL. We first optimized measurement conditions, i.e., the sampling interval and the nearest sampling point from the surface. Then we evaluated the performance of the proton radiography system by use of the step phantoms and a patient-specific range compensator. The step phantom measurement was designed to evaluate WEPL accuracy and standard deviation, and the patient-specific compensator was utilized to evaluate image quality dependency on the shifting motions of the DWRS. Based on the optimization and evaluation in the radiographic setting, a cylindrical phantom having multiple insert holes was used to obtain proton CT and the image contrasts of the holes were evaluated. This study successfully demonstrates the feasibility of using the DWRS for proton radiography and CT.

Fluorescence growth of self-polymerized fluorescence polydopamine for ratiometric visual detection of DA

In this work, a novel and facile ratiometric fluorescence probe was prepared for the visual detection of dopamine (DA). In this detection system, red-emission CdTe@SiO2 (r-QDs@SiO2) was used as steady core of the probe and inverse microemulsion method was applied to synthesize uniform r-QDs@SiO2, this step could protect CdTe from contacting with human skin directly. Polydopamine (PDA) acted as response signal to detect DA, a very handy method which just combined polyethyleneimine (PEI) with DA together to synthesize PDA, this way for synthesis of PDA was much time-saving and non-toxic than any other methods. Differently from traditional analysis processes, the products of this experiment were also the analysis substances in final. Under optimum measurement conditions, the dual-emission ratiometric fluorescence probe was used for detections of DA in a concentration ranged from 10μM to 80μM with a detection limit of 0.12μM, with addition of DA the color of the probe changed from red to green watched by naked eyes. In addition, the developed probe was also used for detections of DA in human serum samples successfully. This study provides a simple, time-saving and non-toxic approach for detections of DA without the requirement of complex equipment.

수학적 창의성 태도 검사에서 수학영재와 일반학생의 다집단 일반화가능도 분석

본 연구의 목적은 측정학적 이론을 바탕으로 수학영재 집단과 일반학생 집단에서 수학적 창의성 태도 검사 점수에 영향을 미치는 오차 요인들의 상대적인 영향력과 적정 수준의 신뢰도에 도달하는 효율적인 측정 조건을 탐색하는 데 있다. 이를 위해 109명의 중등 수학영재와 125명의 일반 중학생을 대상으로 실시한 수학적 창의성 태도 검사 결과에 다변량 일반화가능도 분석을 수행하였다. 주요 분석 결과는 다음과 같다. 첫째, 수학적 창의성 태도 검사는 신뢰도를 기준으로는 일반학생 집단에서, 조건부 측정 오차를 기준으로는 수학영재 집단에서 좀 더 적합한 것으로 나타났지만, 두 집단에서 모두 시행할 수 있는 신뢰로운 측정도구인 것으로 나타났다. 둘째, 수학적 창의성 태도 검사에서 신뢰도를 높이기 위해서는 수학영재 집단의 경우 수렴적 태도를 높게. 반면에 일반학생 집단의 경우 발산적 태도와 문제해결 태도를 높게 반영하여야 하는 것으로 나타났다. 셋째, 수학영재 집단의 경우 발산적 태도, 문제해결 태도, 수렴적 태도의 다차원적인 요소를 반영하는 경우, 그리고 일반학생 집단의 경우 발산적 태도만으로도 적정 수준의 신뢰도에 도달하는 것으로 나타났다. 마지막으로 이러한 연구결과들을 바탕으로 수학적 창의성 태도 검사 활용 방안 및 향후 연구 방향을 제시하였다. The purpose of this study was to investigate the relative influence of multiple error sources and to find optimal measurement conditions that obtain a desired level of reliability of a creative attitude test in mathematical creativity. This study analyzed the scores of the Creative Attitude Scale-Korea allowed to access publicly of 125 general students and 109 mathematically gifted students by performing a multivariate generalizability analysis. The main results were as follows. First, based on reliability, the Creative Attitude Scale-Korea was measured less precisely for mathematically gifted students. On the contrary, based on the conditional standard error of measurement, it was measured less precisely for general students. However, the Creative Attitude Scale-Korea showed strong reliability in both groups. Second, the optimal weights should adjust to .3, .3, .4 in mathematically gifted students and .4, .4, .2 in general students with three scoring components of divergent attitude, problem solving attitude, and convergent attitude based on the maximum reliability. Third, to approach desirable reliability, it is possible to use one component of divergent attitude in general students but three components of divergent attitude, problem solving attitude, and convergent attitude in mathematically gifted students. Finally this study proposed application plans for the Creative Attitude Scale-Korea and future directions of research.

Determination of the total cadmium, copper, lead and zinc concentrations and their labile species fraction in apple beverages by flow-through anodic stripping chronopotentiometry.

An analytical procedure for operationally defined speciation of Cd, Cu, Pb and Zn in apple beverages by anodic stripping chronopotentiometry (ASCP) is presented. Optimal measurement conditions were set down to reliably determine the fraction of the labile metals species. The mean total concentrations of Cu, Pb and Zn were 69±20, 7.3±3.3, and 129±59μgL-1 in apple juices, and 18±3, 4.2±0.1, 53±5μgL-1 in apple drinks, respectively. The contributions of the fraction of the ASCP-labile species varied from 43 to 63% (Cu), from 32 to 42% (Pb) and from 38 to 58% (Zn). The Cd content in all analyzed samples was below 0.02μgL-1. The detection limits (DLs) achieved for Cu, Pb and Zn were 0.04μgL-1 (Cu), 0.02μgL-1 (Pb), and 0.10μgL-1 (Zn).

音響管粉粒体レベルスイッチ

This paper describes a new type of level switch which detects the existence of light, hot particulates such as ash in a tank. Here we employed an acoustic tube method. A port of the tube was driven by a piezo-sounder at less than its resonance frequency and the length L of the tube was selected to have the same resonance frequency, i.e., L=n×(half of the wave length). If the other port is covered by particulates, the acoustic impedance at the resonance frequency increases, which yields increases of the electric impedance of the piezo device. The sound velocity increases in proportion to the temperature, which may deteriorate the optimal measurement condition, i.e., the length of tube is not optimal at the altered temperature. However theoretical studies showed that covering a detected port by particulates mostly influenced the acoustic viscosity which is less influenced by the temperature change. As a result of theoretical studies, we showed that the proposed method can work in a certain temperature range. We verified the theoretical results using experiments which showed that the proposed method worked in the temperature range from 5°C to 80°C with a piezo sounder with 760 resonance frequency and an acoustic tube with half the wave length. Moreover, it detected particles with low bulk density such as those with 13kg/m3. We also conducted an experiment to judge the existence of gravel heated to 450°C in at a room temperature of 23°C which was successful.

Biogenic fraction determination in fuels – Optimal parameters survey

The novel method for biogenic component determination in liquid fuels by direct measurement of the 14C activity concentration via liquid scintillation counting (LSC) technique has been used in few laboratories worldwide. This paper presents results of the development of method for bio-component quantification in fuel mixtures in the Nuclear Physics Laboratory Novi Sad, Serbia, as well as their comparison to established methodology in literature with intent to define optimal parameters and measurement conditions for 14C determination in biofuels. Therefore, the purpose of the paper is to give comprehensive overview of optimal parameters such as scintillation cocktail and vial selection, fuel/cocktail ratio and best calibration procedure of liquid scintillation counter Quantulus 1220™, with practical information for laboratories that intend to develop this technique. Biodiesel produced from two different feedstock materials was mixed with two commercial fossil matrices to produce fuel blends containing 1–100% FAME (Fatty Acid Methyl Esters), which were analyzed for calibration purposes. Analytical study of relation between the detected released energy and quench level led to establishment of calibration curves specific to the fuel types produced in this moment on the market in Serbia.

Monte Carlo study of the effective Sherman function for electron polarimetry

The PEBSI Monte Carlo simulation was upgraded towards usefulness for electron Mott polarimetry. The description of Mott scattering was improved and polarisation transfer in Møller scattering was included in the code. An improved agreement was achieved between the simulation and available experimental data for a 100keV polarised electron beam scattering off gold foils of various thicknesses. The dependence of the effective Sherman function on scattering angle and target thickness, as well as the method of finding optimal conditions for Mott polarimetry measurements were analysed.

Rapid determination of aminotris(methylenephosphonic acid) in water by ultraviolet photooxidation

ABSTRACTAminotris(methylenephosphonic acid) is a commonly used reagent in circulating water to minimize deposit and corrosion inhibition that should be monitored. Aminotris(methylenephosphonic acid) was determined in circulating water using a photooxidation reaction to produce orthophosphate that was subsequently determined. The optimal conditions for analytical measurements were 1.0 g/L sodium persulfate oxidizing agent and a digestion time of 8 min. It was not necessary to control the pH. The optimum digestion efficiency of aminotris(methylenephosphonic acid) was 95% with good accuracy and precision and recoveries between 98% and 105%. The reported protocol is simple, rapid, and allows the on-line monitoring of aminotris(methylenephosphonic acid) in circulating water.

Universal evaluation of combined standard uncertainty for rotating-element spectroscopic ellipsometers.

We present for the first time a universal expression for the combined standard uncertainty for all types of rotating-element spectroscopic ellipsometers (RE-SEs). Specifically, we introduce general model functions as universal analytic expressions for the combined standard uncertainties of the ellipsometric sample parameters. The model functions are expressed as functions of influencing quantities that are not known exactly. The detailed expressions for the model functions are provided for the common RE-SEs. Our approach can be used for instrumentation, standardization, simulation, metrology, optimization of measurement conditions, and performance comparison between RE-SEs.

Methodology for determining critical dimension scanning electron microscope measurement condition of sub-20 nm resist patterns for 0.33 NA extreme ultraviolet lithography

A methodology to determine the optimum measurement condition of extreme ultraviolet (EUV) resist patterns in a critical dimension scanning electron microscope has been established. Along with many parameters that need to be optimized simultaneously, there are conflicting requirements of small resist shrinkage and high measurement precision. To overcome these difficulties, we have developed a methodology for ArF resist patterns from shrinkages and precisions predicted by the Taguchi method. In this study, we examined the extendibility of the methodology to sub-20 nm EUV resist patterns. The predicted shrinkage by the Taguchi method for an 18 nm EUV resist pattern showed a large prediction error due to its different dependence on acceleration voltage from ArF, so we used the shrinkage curve to predict shrinkage instead of the Taguchi method, as shrinkage depends only on irradiated electron dose. In contrast, precision can be predicted well by the Taguchi method as with ArF. We propose a methodology that consists of separate prediction procedures for shrinkage and precision using the shrinkage curve and Taguchi method, respectively. The proposed method was applied to an 18-nm EUV resist pattern. The optimum measurement condition with shrinkage of 1.5 nm and precision of 0.12 nm was determined.

Arsenic Speciation of Waters from the Aegean Region, Turkey by Hydride Generation: Atomic Absorption Spectrometry.

Arsenic in drinking water is a serious problem for human health. Since the toxicity of arsenic species As(III) and As(V) is different, it is important to determine the concentrations separately. Therefore, it is necessary to develop an accurate and sensitive method for the speciation of arsenic. It was intended with this work to determine the concentrations of arsenic species in water samples collected from Izmir, Manisa and nearby areas. A batch type hydride generation atomic absorption spectrometer was used. As(V) gave no signal under the optimal measurement conditions of As(III). A certified reference drinking water was analyzed by the method and the results showed excellent agreement with the reported values. The procedure was applied to 34 water samples. Eleven tap water, two spring water, 19 artesian well water and two thermal water samples were analyzed under the optimal conditions.

The effect of irradiance and integration time in in vivo normal skin Raman measurements assessed by multivariate statistical analysis

BACKGROUND: The successful discrimination of the subtle spectral characteristics of human skin in Raman spectra requires optimal acquisition parameters. We explore the translational momentum of Raman spectroscopy towards clinical practice by fine-tuning two basic experimental parameters (irradiance and integration time) of a portable Raman system used in skin measurements. OBJECTIVE: The aim of this study is to construct a generic protocol for recording the optimal Raman signal for in vivo skin measurements. METHODS: In vivo spectra were collected from two individuals of normal Fitzpatrick type III skin type. We assessed two different irradiation setups with three different integration times each by separating the raw signal from the noise using multivariate analysis. RESULTS: Our results showed that under a time threshold no optimal measurement conditions can be achieved. On the other hand, increased laser power and acquisition time do not offer a significant advantage over the selected lower values. Baseline correction is the most critical component for analysing normalized skin Raman spectra. CONCLUSIONS: A simple working protocol based on multivariate statistics offers the relative adjustment of irradiance and signal integration time among other experimental parameters that must be examined for optimal Raman measurements of skin.

Study of energy transfer by different light curing units into a class III restoration as a function of tilt angle and distance, using a MARC Patient Simulator (PS)

ObjectiveThe MARC Patient Simulator (MARC PS) enables researchers to observe the influence of handling errors on the radiant exposure that is delivered by light curing units (LCUs). Changes in the tilt angle and distance of the light guide exit face in relation to the surface of the composite increment have a distinct effect on the total amount of light delivered during polymerization and may cause insufficient conversion of the material. Therefore, the aim of the present study was to determine the influence of the tilt angle and distance of irradiance on the efficiency of light application by recording the total amount of energy using the anterior tooth sensor of the MARC PS. MethodsThe influence of the tilt angle and distance of the light guide to the sensor surface on the delivered radiant exposure was examined for three different LCUs (Celalux 2 [C2], Bluephase [BP] and Translux Powerblue [TPB]). The measurements were performed for 20s each with five different tilt angles (α=0°, 5°, 10°, 15°, 20°) and nine different distances (L=1, 2, 3, 4, 5, 6, 7, 8, 9mm). ResultsFor all LCUs, a distinct influence of the tilt angle on the delivered amount of fluence was found. At 0° tilt the C2 delivered a total light energy of 38.55J/cm2. By increasing the tilt of the light guide the amount of energy applied significantly decreased. At 20° tilt a reduction by 31.2% of the original light fluence was recorded. However, the C2 was the most powerful LCU measured. Even under optimum measurement conditions, the BP delivered a fluence of only 14.8J/cm2. At a tilt angle of 20°, though, the light sensor still registered 92.7% of the original output power. Under the same conditions, the TPB delivered 81.4%.With increasing distance of the light guide exit face to the surface of the sensor all LCUs showed a significant loss in delivered light energy. At a distance of 2mm the C2 showed a reduction by 46.7%, whereas total fluence of BP and TPB were reduced by 3.8% and 4.8%, respectively. SignificanceThe choice of LCU and the application of an appropriate curing time are important for successful polymerization. Nevertheless, a perpendicular positioning of the light guide as close as possible to the surface of the composite increment is of essential importance in order to ensure sufficient delivery of light.

Amperometric nitrite sensor based on a glassy carbon electrode modified with multi-walled carbon nanotubes and poly(toluidine blue)

An amperometric nitrite sensor modified with multi-walled carbon nanotubes (MWCNTs) and poly(toluidine blue) (PTB) on glassy carbon electrode was constructed. The surface morphology of the composite- modified electrode was characterized by scanning electron microscopy, and the electrochemical response behavior and electrocatalytic oxidation mechanism of nitrite were investigated by cyclic voltammetry. The high surface-to-volume ratio of MWCNTs and PTB brings the electrochemical sensing unit and nitrite in full contact. This renders the electrochemical response extremely sensitive to nitrite. Under the optimal measurement conditions and a working voltage of 0.73 V (vs. SCE), a linear relationship is obtained between the oxidation peak current and nitrite concentration in the range of 39 nM–1.1 mM, and the limit of detection is lowered to 19 nM (at an S/N ratio of 3). The sensor was successfully applied to the determination of nitrite in greenhouse soils.

Saturation dynamics and working limits of saturated absorption cavity ringdown spectroscopy.

Cavity ringdown spectroscopy (CRDS) in the linear absorption regime is a well-established method for sensitive trace gas detection, but only a few studies have addressed quantitative measurements in the presence of a saturated sample. In fact, saturation is usually avoided in order to escape from the required complex modeling of the saturation process that depends on the characteristics of the absorbing species, its interaction with the surrounding gas as well as on the temporal and spectral characteristics of the cavity excitation. Conversely, the novel saturated-absorption cavity ringdown spectroscopy approach (SCAR/Sat-CRDS) takes advantage of sample saturation in order to allow one to extract both the gas absorption and the empty cavity loss rates from a single ringdown event. Using a new continuous-wave infrared CRD spectrometer equipped with a tunable narrow-bandwidth high-power OPO laser system and a 18 bit digitizer, the transient dynamics of absorption saturation and the working limits of the Sat-CRDS approach in terms of its ability to extract reliable trace gas concentrations have been experimentally studied in this work. Using a strong methane transition as a test case, the excitation power P0 and saturation power PS have been systematically varied to explore a wide range of saturation regimes. At pressures 5 μbar < p < 2 mbar, the saturation intensity revealed a nearly linear pressure dependence showing that non-collisional processes contribute to the overall relaxation. A ratio of P0/PS ≈ 15 turned out to be optimal with working limits of 5 < P0/PS < 300. Moreover, the ratio of the absorption and empty cavity loss rates, γg/γc, has been varied to test the dynamic range of the method. At γg > γc, a pronounced coupling between the two parameters has been observed. Finally, a standard error analysis was performed revealing that the Sat-CRDS approach holds its advantages over conventional CRDS implementations in particular when the attainable ultimate detection sensitivity is limited by uncertainties in the empty cavity ringdown constant.

Application of a novel electrochemical sensor containing organo-modified sericite for the detection of low-level arsenic.

A simple cyclic voltammetry (CV) analytical method with organo-modified sericite for the working electrode was investigated to detect As(III) in an aquatic environment, and optimal conditions for the reliable measurement of trace amounts of As(III) were studied. A distinct, specific peak was clearly observed at 0.8V due to the reduction of H3AsO4 to H3AsO3. The specific peak current of arsenic increased with increasing the concentration of As(III) and initially increased proportionally to the scan rates. However, it disappeared as the scan rate increased over 400mV/s. Because the surface of the organo-modified sericite electrode rapidly became saturated with As(III) when the deposition time increased, an optimal deposition time was determined as 60s. Pb(2+) had no significant influence on the peak signal of As(III), whereas it was reduced as the ratio of Cu/As increased. Considering the detection limit of arsenic (1ppb), this system can be used to detect low levels of As(III) in water systems.

Minimization and Mitigation of Wire EDM Cutting Errors in the Application of the Contour Method of Residual Stress Measurement

The contour method of residual stress measurement relies on the careful application of wire electro-discharge machining (WEDM) for the cutting stage. Changes in material removal rates during the cut lead to errors in the final calculated values of residual stress. In this study, WEDM cutting parameters have been explored to identify the optimum conditions for contour method residual stress measurements. The influence of machine parameters on the surface roughness and cutting artifacts in the contour cut is discussed. It has been identified that the critical parameter in improving the surface finish is the spark pulse duration. A typical cutting artifact and its impact on measured stress values have been identified and demonstrated for a contour cut in a welded marine steel. A procedure is presented to correct contour displacement data from the influence of WEDM cutting artifacts, and is demonstrated on the correction of a measured weld residual stress. The corrected contour method improved the residual stress magnitude up to 150 MPa. The corrected contour method results were validated by X-ray diffraction, incremental center hole drilling, and neutron diffraction.

An approach to potentiometric sensing of sugars: Baker's yeast assisted pH electrode

Rapid development of “electronic tongue” technology requires novel sensors with response toward various classes of taste substances. Potentiometric sensors gained wide acceptance for these purposes, however, they cannot provide for sensitivity toward numerous sugars, since typical carbohydrates are normally not ionized under measurement conditions. We report on feasibility study of an approach to potentiometric sensing of sugars using Saccharomyces cerevisiae (baker's yeast) as a sample modulator. The ability of the yeast to ferment sugars and proportionally increase sample acidity can be tracked with ordinary pH glass electrode and can be related to the amount of sugar in a quantitative way. We optimized measurement conditions with yeasts and demonstrated the applicability of this simple approach to quantitative sucrose determination in apple juices.