Chromatic Technique Research Articles

Assessment of UHF Frequency Range for Failure Classification in Power Transformers.

Ultrahigh-frequency (UHF) sensing is one of the most promising techniques for assessing the quality of power transformer insulation systems due to its capability to identify failures like partial discharges (PDs) by detecting the emitted UHF signals. However, there are still uncertainties regarding the frequency range that should be evaluated in measurements. For example, most publications have stated that UHF emissions range up to 3 GHz. However, a Cigré brochure revealed that the optimal spectrum is between 100 MHz and 1 GHz, and more recently, a study indicated that the optimal frequency range is between 400 MHz and 900 MHz. Since different faults require different maintenance actions, both science and industry have been developing systems that allow for failure-type identification. Hence, it is important to note that bandwidth reduction may impair classification systems, especially those that are frequency-based. This article combines three operational conditions of a power transformer (healthy state, electric arc failure, and partial discharges on bushing) with three different self-organized maps to carry out failure classification: the chromatic technique (CT), principal component analysis (PCA), and the shape analysis clustering technique (SACT). For each case, the frequency content of UHF signals was selected at three frequency bands: the full spectrum, Cigré brochure range, and between 400 MHz and 900 MHz. Therefore, the contributions of this work are to assess how spectrum band limitation may alter failure classification and to evaluate the effectiveness of signal processing methodologies based on the frequency content of UHF signals. Additionally, an advantage of this work is that it does not rely on training as is the case for some machine learning-based methods. The results indicate that the reduced frequency range was not a limiting factor for classifying the state of the operation condition of the power transformer. Therefore, there is the possibility of using lower frequency ranges, such as from 400 MHz to 900 MHz, contributing to the development of less costly data acquisition systems. Additionally, PCA was found to be the most promising technique despite the reduction in frequency band information.

Hydrodynamics and particle array optical characterizations of a high-performance Langmuir–Blodgett process

This paper describes the scientific features of an innovative technique to mass-produce monolayers of hexagonal close-packed structures (HCP) of particles (280–1100 nm). Our technique differs from a continuous roll-to-roll Langmuir–Blodgett (LB) process. It consists of a thin liquid film flowing down an inclined plane channel, the ramp, and entraining deposited particles floating on its surface to form a compact monolayer. Vertical sidewalls limit the entire flow. The main benefits of this technique in comparison with a standard LB process are a gentler push on the floating particles during the assembly and the prospect of better flexibility and scalability in the design of industrial applications. Our disruptive approach presents new control parameters and surprising but challenging hydraulic phenomena due to the flowing liquid. This paper investigates the hydrodynamics of this new LB-type design theoretically and experimentally. We propose an original theoretical prediction of the thickness of the liquid film flowing down the ramp without or with particles on its surface, including within the hydraulic jump region separating the liquid film whose surface is free of particles and the liquid film whose surface is particle-loaded. The experimental determinations of the film thickness obtained by a confocal chromatic technique and moiré topography agree well with our model. In addition, Bragg diffraction topography and false colour topography allow the HCP structure of the compact monolayer of particles to be quantified.

UV–Visible–NIR camouflage textiles with natural plant based natural dyes on natural fibre against woodland combat background for defence protection

Woodland combat background (CB) is a common source of natural plant based natural dyes (NPND). Swietenia Macrophylla, Mangifera Indica, Terminalia Arjuna, Corchorus Capsularis, Camellia Sinensis, Azadirachta Indica, Acacia Acuminata, Areca Catechu and Cinnamomum Tamala were dried-grinded-powdered-extracted-polyaziridine encapsulated-dyed-coated-printed with leafy design on cotton fabric and tested against woodland CB under the reflection engineering of ultraviolet (UV)–visible (Vis)–near infrared (NIR) spectrums and photographic versus chromatic techniques of Vis imaging. The reflection properties of NPND treated and untreated cotton fabric were experimented by UV–Vis–NIR spectrophotometer from 220 to 1400 nm. Six segments of field trialling for NPND treated woodland camouflage textiles were also investigated for concealment, detection, recognition and identification of target signature against forest plants/herbs species; common tree of woodland CB such as Shorea Robusta Gaertn, Bamboo Vulgaris, Musa Acuminata; and a wooden bridge made by Eucalyptus Citriodora & Bamboo Vulgaris. The imaging properties such as CIE L*, a*, b* and RGB (red, green, blue) of NPND treated cotton-garments were captured by digital camera from 400 to 700 nm against tree stem/bark, dry leaves, green leaves and dry wood of woodland CB. Therefore, a colorful matching for concealment, detection, recognition and identification of target signature against woodland CB was verified by Vis camera imaging and UV–Vis–NIR reflection mechanism. UV-protection property of Swietenia Macrophylla treated cotton fabric was also investigated by diffuse reflection for defence clothing. Simultaneous ‘camouflage textiles in UV–Vis–NIR’ and ‘UV-protective’ property of Swietenia Macrophylla treated fabric have been investigated for NPND materials-based textiles coloration (dyeing-coating-printing) which is a new concept for camouflage formulation of NPND dyed-NPND mordanted-NPND coated-NPND printed textiles in terms of ecofriendly source of woodland camouflage materials. Therefore, technical properties of NPND materials and methodologies of camouflage textile assessment have been advanced in addition to coloration philosophy of natural dyed-coated-printed textiles.

Some old 2-(4-(Aryl)- thiazole-2-yl)-3a,4,7,7a-tetrahydro-1H-4,7-tethanoisoindole-1,3(2H)-dione derivatives: Synthesis, inhibition effects and molecular docking studies on Aldose reductase and α-Glycosidase

Utilizing the simple chromatic techniques, Aldose reductase (AR) was derived from sheep liver. In addition, α-glycosidase from Saccharomyces cerevisiae was used as the enzyme. It was determined the interactions between compounds and the enzymes. Molecular docking method used to compare biological activity values of molecules against enzymes.In the current study, the inhibition effect of synthetic isoindol-substitute thiazole derivatives (3a-f) on AR, and α-glycosidase enzymes was studied. In the thiazole series, compound 3b (Ki: 9.70±4.72 M) showed a maximum inhibitory impact towards AR while compound 3f (Ki: 44.40±17.18 M) showed a lowest inhibitory impact towards AR. It was investigated potent inhibition profiles with Ki values in the range of 24.54±6.92–44.25±10.34 M against α-glycosidase. Theoretical results were found consistent with experimental results.Acting as antidiabetic agents, these compounds have the potential to be the selective inhibitor of α-glycosidase and AR enzymes. The biological activities of the studied molecules against AR and α-glycosidase enzymes will be compared with molecular docking method. ADME analysis of the molecules will be done.

A New Acoustic-Based Approach for Assessing Induced Adulteration in Bovine Milk.

Milk is an important dietary requirement for many populations due to its high nutritional value. However, increased demand has also made it prone to fraudulent activity. In this sense, scientists have sought to develop simple, low-cost, and portable techniques to achieve quality control of milk in industry and farms as well. This work proposes a new instrumentation system based on acoustic propagation and advanced signal processing techniques to identify milk adulteration by industrial contaminants. A pair of transmitter-receiver low-cost piezoelectric transducers, configured in a pitch-catch mode, propagated acoustic waves in the bovine milk samples contaminated with 0.5% of sodium bicarbonate, urea, and hydrogen peroxide. Signal processing approaches such as chromatic technique and statistical indexes like the correlation coefficient, Euclidian norm and cross-correlation square difference were applied to identify the contaminants. According to the presented results, CCSD and RMSD metrics presented more effectiveness to perform the identification of milk contaminants. However, CCSD was 2.28 × 105 more sensitivity to distinguish adulteration in relation to RMSD. For chromatic clustering technique, the major selectivity was observed between the contamination performed by sodium bicarbonate and urea. Therefore, results indicate that the proposed approach can be an effective and quick alternative to assess the milk condition and classify its contaminants.

Partial Discharge Electrical Tree Growth Identification by Means of Waveform Source Separation Techniques

Electrical trees are one of the main degradation processes leading to failure of high voltage polymeric insulation. Electrical trees grow under the effect of partial discharges (PD), which can be measured and analyzed for condition monitoring of electrical insulation. In this paper, techniques that are normally used for classification of PD and noise separation were explored in their ability to determine the stage of growth of electrical trees: Spectral Power Clustering Technique (SPCT), Time-Frequency (TF) maps and Chromatic Technique (CT). The techniques allowed to analyze PD signals captured in ultra-high frequency (UHF) range with an antenna during tree growth. Laboratory treeing-samples were made of epoxy resin and trees were generated at six different excitation frequencies: 0.1, 10, 50, 150, 250 and 350 Hz. The results showed that two parameters, part of SPCT and TF maps, were sensitive to the tree progression and showed a consistent relation with the length of the tree: the low-frequency power ratio and the equivalent bandwidth. These two parameters were selected to create a new map, proposed for the characterization of electrical tree growth, which is more consistent and robust than the original separation maps. It was found that the low-frequency content of PD pulses proportionally increased with tree propagation.

Del conocimiento a la práctica: integración de equipos de trabajo por supervisora de enfermería

Esta investigación tuvo por objetivo determinar las estrategias de la enfermera supervisora en la integración de equipos de trabajo de enfermería en una institución hospitalaria. Se trata de una investigación cualitativa realizada en un hospital de segundo nivel de atención, entre agosto de 2017 y julio de 2018. Se aplicó una entrevista individual a 10 enfermeras supervisoras de dicha institución. El análisis se efectuó mediante la técnica cromática y el análisis de contenido; la discusión se elaboró con base en el contraste de los datos obtenidos con la teoría de los Roles de Equipo de Belbin. Se presentan en categorías y subcategorías relacionadas con las características del talento humano de enfermería: nivel de conocimientos, habilidades técnicas, personalidad, habilidades interpersonales y equipos de alto desempeño. Se identificaron las estrategias que las supervisoras de enfermería utilizan al integrar equipos de trabajo.

A chromatic technique for structural damage detection under noise effects based on impedance measurements

Structural health monitoring (SHM) based on electromechanical impedance (EMI) measurements has been extensively studied in recent years and stands out as an effective damage detection approach. The EMI method commonly uses low-cost piezoelectric transducers and structural diagnosis can be accomplished by analyzing the changes in the impedance measurements from the transducers attached to the host structure. Although many studies have proved the effectiveness of the EMI method, one of the most reported problems is the variations in the impedance caused by external noise, which can alter the impedance measurements and limit the effectiveness of the detection and quantification of damage using conventional basic damage indices. Therefore, this paper proposes a new approach for structure feature extraction in noisy environments based on the chromatic signal processing technique associated with the Hinkley criterion, thus aiming to expand the applicability of the EMI method to real applications. Experimental tests were carried out on aluminum and carbon fiber composite plates subjected to various signal noise levels. The experimental results indicate that the proposed approach is more effective for damage detection compared to the basic indices commonly reported in the literature.

ИТОГИ СЕЛЕКЦИИ ECHINACEA PURPUREA (L.) MOENCH В ЦЕНТРАЛЬНОМ РЕГИОНЕ РОССИИ

Background. Echinacea purpurea (L.) Moench is a perennial herbaceous plant of the family Asteraceae introduced from North America. Preparations from crude herbal materials of E. purpurea have a widerange effect against pathologies of the immune system, infectious and inflammatory diseases of the respiratory tract, genitourinary system and musculoskeletal system. Breeding work involving E. purpurea has been carried out at the All-Russian Research Institute of Medicinal and Aromatic Plants (Moscow Province) since 1996 with the aim of developing varieties adapted to the regional environments of Central Russia as well as increasing the yield and quality of raw materials by breeding methods. Objects and methods. In the process of breeding in 2009–2016, the collection material of E. purpurea was propagated vegetatively in the field, while the breeding material was reproduced by sowing and transplanting techniques from the seeds obtained under controlled pollination conditions. In the control nursery of the 2nd–5th years of vegetation, accessions promising for breeding were studied and evaluated by comparing them with the reference (var. ‘Tanyusha’). Breeding accessions (Nos. 1-09, 2-09 and 22-09) were obtained by individual selection based on the biological collection of VILAR (Nos. 79, 80 and 38) received in 1998 from the UK (Exchange Seed Fund). Seeds were sown into plots (total area of 9.6 m2 ) with a 4-fold replication. The yield of crude herbal materials (above-ground part) was registered at the beginning of the flowering phase (the first 10 days of August), and fresh and dry mass of the accessions were measured (after 48-hour ventilated drying at 45°C). Chemical analysis of crude herbal materials was made to find the sum of the derivatives of oxycinnamic acids calculated as chicoric acid using chromatic spectrophotometric techniques according to Temporary Pharmacopoeial Article 42-2371-94 and Private Pharmacopoeial Article in State Pharmacopoeia XIII. Results. According to the results of competitive variety trials in 2014–2016, the breeding accessions reliably exceeded the reference ‘Tanyusha’ in a set of economically valuable parameters: in crude herb yield by 10–27%; in the content and total harvest of active substances in crude herb materials by 7–18% and 21–80%, respectively; and in seed yield by 35–47%. Breeding accessions demonstrated normal adaptability to regional conditions (duration of the growing season was 174–176 days, and winter hardiness reached 89–94%). Conclusion. Accession No. 1-09, the best according to a set of economically valuable and biological traits as the results of competitive variety trials have shown, has been submitted to the State Variety Trials as a new cultivar of E. purpurea under the name ‘Severyanka’.

Chromatic Techniques to Evaluate Inhibition of Enzymatic Browning in Avocado Puree

Chromatic Techniques to Evaluate Inhibition of Enzymatic Browning in Avocado Puree

Chromatic techniques for in vivo monitoring jaundice in neonate tissues

Objective: A chromatic method is described for providing a preliminary indication of unacceptable bilirubin levels in a newly born baby in order to avoid the development of serious mental deficiencies. The aim was to investigate the reliability of a new chromatic approach using a novel template unit for a preliminary, non-invasive monitoring of the skin tissue of newly born babies with jaundice and its capability for use with different mobile phone cameras. Approach: A description of the monitoring system is given along with an explanation of the monitoring technique used. Preliminary tests have been performed on 48 different neonates each being addressed by one of six different mobile phone cameras, which were randomly available to the operating clinicians. Main results: The test results have a correlation (R2) of 0.81, a sensitivity (Sn) of 0.97, a specificity (Sp) of 0.82, a positive predictive value (PPV) of 0.95 and a negative predictive value (NPV) of 0.9. Significance: The significance of the results obtained is that they show the approach to have a high level of fail-safe reliability in indicating the bilirubin levels when compared with blood test results. The results also show that the approach can be used with a few different mobile phone cameras and that because of its non-invasive nature and its cost effectiveness, has the potential for remote use from a medical hospital to provide an immediate preliminary diagnosis.

Percepción social de usuarias atendidas exclusivamente por enfermeras en la etapa perinatal

El artículo muestra la atención exclusiva de enfermeras en una maternidad, cuyo objetivo fue analizar las representaciones sociales de las usuarias acerca de la atención brindada por las enfermeras obstetras en la institución. Es una investigación con enfoque cualitativo, descriptivo; direccionado por la teoría de las representaciones sociales de Moscovici. Se entrevistó a 34 mujeres atendidas en la maternidad. El análisis de datos se efectuó mediante marco interpretativo, seleccionando las ideas destacadas por medio de técnica cromática; en seguida, se discute los datos empíricos confrontados con la teoría. Las usuarias señalan que la atención recibida se inscribió en un marco de humanización, responsabilidad y confianza, lo cual posibilita la atención de un parto de acuerdo con sus costumbres que, con base en la teoría, refleja autonomía profesional. Se concluye que el modelo de atención muestra que el cuidado de enfermería se basa en conocimientos, experiencia y valores que potencializan la práctica, desde la que se aprecia el cuidado humano, cálido y personalizado.

A Comparison of Inductive Sensors in the Characterization of Partial Discharges and Electrical Noise Using the Chromatic Technique.

Partial discharges (PDs) are one of the most important classes of ageing processes that occur within electrical insulation. PD detection is a standardized technique to qualify the state of the insulation in electric assets such as machines and power cables. Generally, the classical phase-resolved partial discharge (PRPD) patterns are used to perform the identification of the type of PD source when they are related to a specific degradation process and when the electrical noise level is low compared to the magnitudes of the PD signals. However, in practical applications such as measurements carried out in the field or in industrial environments, several PD sources and large noise signals are usually present simultaneously. In this study, three different inductive sensors have been used to evaluate and compare their performance in the detection and separation of multiple PD sources by applying the chromatic technique to each of the measured signals.

Experimental Study of Water Film Dynamics Under Wind Shear and Gravity

Aircraft icing poses a serious threat to flight safety. Unfrozen impinging water on the surface of the aircraft will run back under the effect of high-speed airflow, altering liquid distribution and heat transfer characteristics. In this paper, a series of experiments are conducted over a wide range of wind speeds (), film Reynolds numbers (), and inclined angles (, , ) to investigate the dynamics of thin water film on an aluminum substrate. The superficial morphology of the water film is investigated by a high-speed camera, and the instantaneous film thicknesses are measured by a laser focus displacement meter based on a confocal chromatic technique. The interface shape is found to consist of an underlying thin film and multiple scaled fluctuations; therefore, the results are divided into two parts for analysis: the mean film thickness and the root-mean-square thickness. A relationship between the mean film thickness and the wind speed, the film Reynolds number, the inclined angle is proposed. After nondimensionalized processing based on the triangular relationship, the averaged film thickness data agree with the previous model of an error within 25%. New correlations to calculate the interfacial shear stress and superficial roughness are suggested within the experimental range.

Experimental investigation of shear-driven water film flows on horizontal metal plate

In this article, an experimental investigation has been conducted to characterize the instantaneous thickness of the surface water film driven by high-speed airflow pertinent to aerodynamic icing and anti-icing modeling. Non-intrusive results of the film flowing on a metal plate were obtained using the high-speed camera and confocal chromatic technique. The wind speed (Ua) ranges from 17.8 m/s to 52.2 m/s, and the film Reynolds number (Ref) ranges from 26 to 128. The effect of the high-speed airflow on the structure of the wave film was observed and analyzed qualitatively. A new correlation of the interfacial shear factor was proposed for the prediction of the average film thickness. The predictions were compared with the previous annular flow models by applying the dimensionless analysis method and a good agreement is achieved. The superficial roughness, characterized by root-mean-square of the thickness, was well-correlated using a piecewise linear function of the average film thickness. Furthermore, a comprehensive description of the superficial waves including spectrum analysis and division of film thickness data between underlying film and large waves was presented. Transformations of the wave frequency and amplitude with the wind speed and the film Reynolds number were also addressed.

Control of 3D IC process steps by optical metrologies

This paper evaluates various optical metrology techniques for in-line control of the uniformity of 3D stacked structures. Advanced packaging technologies are rapidly evolving and 3D architectures require very well controlled process steps. Optical metrology techniques are now used for TSV but also for interconnect processing. In engineering mode, at the process implementation step, these techniques must be evaluated and then used to get uniform and repeatable processes. Among the 3D TSV Via middle process flow, the temporary bonding, wafer thinning and TSV reveal are key 3D process steps to get a uniform backside copper nail signature. High aspect ratio TSV are etched in Front End of the line and deep reactive ion etching systems generates radial non uniformities signatures. The wafer backside processing challenge consists in compensating this issue among the entire wafer surface. In this paper, all these process steps were characterized in order to quantify their specific intra-wafer dispersion signature .of the related key parameters. Cross correlation between the various intra-wafer process step signatures was then analyzed to verify the data set consistency and several process parameters analyzed to get a simple model. This model was then used to get a very uniform copper nail signature. For small diameter TSV and corresponding copper nails, a comparison has been done between full field OCT and confocal chromatic techniques.

A Novel Method to Handle the Partial Occlusion and Shadow Detection of Highway Vehicles

This study proposes a novel method for resolving the partial occlusion and shadow of moving vehicles seen in a sequence of highway traffic images captured from a single roadside fixed camera position. The proposed method detects the shadow regions of foreground/moving vehicles in any direction with no human intervention. Also, it handles the partially occluded vehicles in three different states on the highway traffic scene. The moving vehicles are detected using the background subtraction method followed by using the dilation and erosion operations. In this step, every segmented moving vehicle has an extracted Feature Vector (FV) which is used to initialize the Shadow Searching Window (SSW). Then, a chromatic based analysis technique uses the semi mean value of RGB colour space of moving vehicle region pixels as a threshold value to discriminate the shadow of moving vehicles despite the direction of movement. Finally, the partially occluded vehicles are handled using a new training procedure based on previous estimations to calculate the new moving vehicle sizes. These sizes are employed to separate and highlight the partially occluded vehicles by drawing the bounding boxes for each moving vehicle.

SU‐E‐T‐526: On the Linearity, Stability and Beam Energy Dependence of CdSe Quantum Dots as Scintillating Probes

Purpose:Structure and energy transfer mechanisms confer colloidal quantum dots (cQDs) interesting properties, among them their potential as scintillators. CdSe multi‐shell cQDs in powder were investigated under photons irradiation. The purpose of this work is to characterize signal to dose linearity, stability with time and to quantify the dependence of their light output with beam energy.Methods:The cQDs are placed at the extremity of a non‐scintillating plastic collecting fiber, with the other extremity connected to an Apogee U2000C CCD camera. The CCD camera collects the fluorescence light from irradiated cQDs from which the delivered dose is extracted. This signal is corrected for Cerenkov contamination at MV energies using the chromatic technique. The detector was irradiated with two devices: Xstrahl 200 orthovoltage unit for 120, 180 and 220 kVp and a Varian Clinac iX for 6 and 23 MV.Results:Linear output response with varying dose is observed for all beam energies with R2 factors > 0,999. Reproducibility measurements were performed at 120 kVp: the same set‐up was irradiated at different time intervals (one week and three months). The results showed only a small relative decrease of light output of 3,2 % after a combine deposited dose of approximately 95 Gy. CdSe nanocrystals response has been studied as a function of beam energy. The output increases with decreasing energy from 120 kVp to 6 MV and increase again for 23 MV. This behavior could be explained in part by the cQDs high‐Z composition.Conclusion:The fluorescence light output of CdSe cQDs was found to be linear as a function of dose. The results suggest stability of the scintillation output of cQDs over time. The specific composition of cQDs is the main cause of the observed energy dependence. We will further look into particle beam dependence of the cQDs. Bourse d' excellence aux etudes graduees du CRC (Centre de Recherche sur le Cancer, Universite Laval)Bourse d' excellence aux etudes graduees du CRC (Centre de Recherche sur le Cancer, Universite Laval)

Condition monitoring of high voltage transformer oils using optical chromaticity

The motivation for the present contribution was to produce a cost effective, convenient system for the optical monitoring of degraded high voltage transformer oils using the chromaticity of polychromatic light transmitted through the oil. The technique uses readily available and portable instrumentation. Examples of results for typical oil samples have been obtained with the technique and comparisons made with the conventional technique of Colour Index. It is shown how the chromatic technique can supplement the Colour Index approach to provide additional information about changes in the transformer oil, such as the presence and extent of solid micro-particles.

A portable system for identifying urinary tract infection in primary care using a PC-based chromatic technique

An approach is described for monitoring urine samples using a portable system based on chromatic techniques and for predicting urinary tract infection (UTI) from the results. The system uses a webcam–computer combination with the screen of a computer visual display unit as a tuneable illumination source. It is shown that the system can operate in a robust manner under ambient lighting conditions and with potential for use as a point of care test in primary care. The present approach combines information on urine liquid concentration and turbidity. Its performance in an exploratory study is compared with microbiological culture of 200 urine samples, of which 79 had bacterial growth >105 colony forming unit/millilitre (cfu ml−1) indicative of UTI. It is shown that both sensitivity and negative predictive value of 0.92 could be achieved.