Gen-2 hand-held optical imager towards cancer imaging: reflectance and transillumination phantom studies.

PubMed

Gonzalez, Jean; Roman, Manuela; Hall, Michael; Godavarty, Anuradha

2012-01-01

Hand-held near-infrared (NIR) optical imagers are developed by various researchers towards non-invasive clinical breast imaging. Unlike these existing imagers that can perform only reflectance imaging, a generation-2 (Gen-2) hand-held optical imager has been recently developed to perform both reflectance and transillumination imaging. The unique forked design of the hand-held probe head(s) allows for reflectance imaging (as in ultrasound) and transillumination or compressed imaging (as in X-ray mammography). Phantom studies were performed to demonstrate two-dimensional (2D) target detection via reflectance and transillumination imaging at various target depths (1-5 cm deep) and using simultaneous multiple point illumination approach. It was observed that 0.45 cc targets were detected up to 5 cm deep during transillumination, but limited to 2.5 cm deep during reflectance imaging. Additionally, implementing appropriate data post-processing techniques along with a polynomial fitting approach, to plot 2D surface contours of the detected signal, yields distinct target detectability and localization. The ability of the gen-2 imager to perform both reflectance and transillumination imaging allows its direct comparison to ultrasound and X-ray mammography results, respectively, in future clinical breast imaging studies.

Reflection: moving from a mandatory ritual to meaningful professional development.

PubMed

Murdoch-Eaton, Deborah; Sandars, John

2014-03-01

Reflection has become established as a key principle underpinning maintenance of standards within professional education and practice. A requirement to evidence reflection within performance review is intended to develop a transformative approach to practice, identify developmental goals, and ultimately, improve healthcare. However, some applications have taken an excessively instrumental approach to the evidencing of reflection, and while they have provided useful templates or framing devices for recording individualistic reflective practice, they potentially have distorted the original intentions. This article revisits the educational theory underpinning the importance of reflection for enhancing performance and considers how to enhance its value within current paediatric practice.

Self-Reflection, Insight, and Individual Differences in Various Language Tasks

ERIC Educational Resources Information Center

Xu, Xu

2011-01-01

This study explored the relationships of self-reflection and insight with individuals' performances on various language tasks. The Self-Reflection and Insight Scale (SRIS; Grant, Franklin, & Langford, 2002) assessed individual differences in three factors: engagement in reflection, need for reflection, and insight. A high need for reflection was…

Reflectivity and Teaching Performance of Novice Teachers: Three Years of Investigation

ERIC Educational Resources Information Center

Pultorak, Edward; Barnes, Debbie

2009-01-01

The purpose of this 3-year investigation was to determine if a relationship exists between teacher reflectivity and the classroom performance of novice teachers when final evaluations are aligned with national standards. This study included 98 novice teachers enrolled in their final field-based teaching experience. Participants reflected over two…

A Reflective Learning Framework to Evaluate CME Effects on Practice Reflection

ERIC Educational Resources Information Center

Leung, Kit H.; Pluye, Pierre; Grad, Roland; Weston, Cynthia

2010-01-01

Introduction: The importance of reflective practice is recognized by the adoption of a reflective learning model in continuing medical education (CME), but little is known about how to evaluate reflective learning in CME. Reflective learning seldom is defined in terms of specific cognitive processes or observable performances. Competency-based…

Self-Reflection and Academic Performance: Is There a Relationship?

ERIC Educational Resources Information Center

Lew, Magdeleine D. N.; Schmidt, Henk G.

2011-01-01

The purposes of the present study were two-fold: first, to evaluate whether reflection journal writing was effective in promoting self-reflection and learning, and whether students become better at self-reflection if they engage continuously in reflection journal writing. To that end, the reflection journals of 690 first-year applied science…

The Effect over Time of a Video-Based Reflection System on Preservice Teachers' Oral Presentations

ERIC Educational Resources Information Center

Cavanagh, Michael; Bower, Matt; Moloney, Robyn; Sweller, Naomi

2014-01-01

We report the development of preservice teachers' oral presentation performance based on a technology-mediated video reflection system. Participants video-recorded oral presentations and uploaded them to an online blog to view and reflect on their performance and that of their peers. Four presentations by forty-one participants were analysed…

Encouraging Reflective Practice in Conservatoire Students: A Pathway to Autonomous Learning?

ERIC Educational Resources Information Center

Carey, Gemma; Harrison, Scott; Dwyer, Rachael

2017-01-01

This paper reports on first-year conservatoire students' reflections on their one-to-one performance learning through a reflective journal. One-to-one lessons have been a central part of the education of performing musicians, although their place in the twenty-first-century conservatoire is not beyond challenge. Recent research has indicated that…

Writing, self-reflection, and medical school performance: the Human Context of Health Care.

PubMed

Stephens, Mark B; Reamy, Brian V; Anderson, Denise; Olsen, Cara; Hemmer, Paul A; Durning, Steven J; Auster, Simon

2012-09-01

Finding ways to improve communication and self-reflection skills is an important element of medical education and continuing professional development. This study examines the relationship between self-reflection and educational outcomes. We correlate performance in a preclinical course that focuses on self-reflection as it relates to contextual elements of patient care (Human Context of Health Care), with educational measures such as overall grade point average, clinical clerkship scores, and Medical College Admission Test (MCAT) scores. Student performance in Human Context of Health Care correlated with MCAT-Verbal scores, MCAT-writing sample scores, clerkship grades, and overall medical school grade point average (R = 0.3; p < 0.001). Writing and self-reflection skills are often neglected in undergraduate medical curricula. Our findings suggest that these skills are important and correlate with recognized long-term educational outcomes.

Considerations in the use of reflective writing for student assessment: issues of reliability and validity.

PubMed

Moniz, Tracy; Arntfield, Shannon; Miller, Kristina; Lingard, Lorelei; Watling, Chris; Regehr, Glenn

2015-09-01

Reflective writing is a popular tool to support the growth of reflective capacity in undergraduate medical learners. Its popularity stems from research suggesting that reflective capacity may lead to improvements in skills such as empathy, communication, collaboration and professionalism. This has led to assumptions that reflective writing can also serve as a tool for student assessment. However, evidence to support the reliability and validity of reflective writing as a meaningful assessment strategy is lacking. Using a published instrument for measuring 'reflective capacity' (the Reflection Evaluation for Learners' Enhanced Competencies Tool [REFLECT]), four trained raters independently scored four samples of writing from each of 107 undergraduate medical students to determine the reliability of reflective writing scores. REFLECT scores were then correlated with scores on a Year 4 objective structured clinical examination (OSCE) and Year 2 multiple-choice question (MCQ) examinations to examine, respectively, convergent and divergent validity. Across four writing samples, four-rater Cronbach's α-values ranged from 0.72 to 0.82, demonstrating reasonable inter-rater reliability with four raters using the REFLECT rubric. However, inter-sample reliability was fairly low (four-sample Cronbach's α = 0.54, single-sample intraclass correlation coefficient: 0.23), which suggests that performance on one reflective writing sample was not strongly indicative of performance on the next. Approximately 14 writing samples are required to achieve reasonable inter-sample reliability. The study found weak, non-significant correlations between reflective writing scores and both OSCE global scores (r = 0.13) and MCQ examination scores (r = 0.10), demonstrating a lack of relationship between reflective writing and these measures of performance. Our findings suggest that to draw meaningful conclusions about reflective capacity as a stable construct in individuals requires 14 writing samples per student, each assessed by four or five raters. This calls into question the feasibility and utility of using reflective writing rigorously as an assessment tool in undergraduate medical education. © 2015 John Wiley & Sons Ltd.

Reflections on Conceptual Tempo: Relationship Between Cognitive Style and Performance as a Function of Task Characteristics

ERIC Educational Resources Information Center

Bush, Ellen S.; Dweck, Carol S.

1975-01-01

Children classified as high-anxious reflective in cognitive style were found to perform as well on speeded tasks as low-anxious reflective children and both groups were found to be faster and more accurate than impulsive children. This suggests redefining cognitive style to stress the strategies used rather than predispositions for particular…

Cost/performance of solar reflective surfaces for parabolic dish concentrators

NASA Technical Reports Server (NTRS)

Bouquet, F.

1980-01-01

Materials for highly reflective surfaces for use in parabolic dish solar concentrators are discussed. Some important factors concerning performance of the mirrors are summarized, and typical costs are treated briefly. Capital investment cost/performance ratios for various materials are computed specifically for the double curvature parabolic concentrators using a mathematical model. The results are given in terms of initial investment cost for reflective surfaces per thermal kilowatt delivered to the receiver cavity for various operating temperatures from 400 to 1400 C. Although second surface glass mirrors are emphasized, first surface, chemically brightened and anodized aluminum surfaces as well as second surface, metallized polymeric films are treated. Conventional glass mirrors have the lowest cost/performance ratios, followed closely by aluminum reflectors. Ranges in the data due to uncertainties in cost and mirror reflectance factors are given.

The Effects of Verbal and Material Rewards and Punishers on the Performance of Impulsive and Reflective Children

ERIC Educational Resources Information Center

Firestone, Philip; Douglas, Virginia I.

1977-01-01

Impulsive and reflective children performed in a discrimination learning task which included four reinforcement conditions: verbal-reward, verbal-punishment, material-reward, and material-punishment. (SB)

The Pitfalls of Collegial Coaching: An Analysis of Collegial Coaching in Medical Education and Its Influence on Stimulating Reflection and Performance of Novice Clinical Teachers

ERIC Educational Resources Information Center

Truijen, Karin J. P.; van Woerkom, Marianne

2008-01-01

Purpose: Competent clinical teachers are essential for clinical teaching. According to the literature, coaching can contribute to improved levels of reflection and better performance of clinical teachers. By engaging in a dialogue about coachee's teaching behaviour, coaches can stimulate reflection of novice teachers. This study aims to gain…

Multi-layer coatings

DOEpatents

Maghsoodi, Sina; Brophy, Brenor L.; Abrams, Ze'ev R.; Gonsalves, Peter R.

2016-06-28

Disclosed herein are coating materials and methods for applying a top-layer coating that is durable, abrasion resistant, highly transparent, hydrophobic, low-friction, moisture-sealing, anti-soiling, and self-cleaning to an existing conventional high temperature anti-reflective coating. The top coat imparts superior durability performance and new properties to the under-laying conventional high temperature anti-reflective coating without reducing the anti-reflectiveness of the coating. Methods and data for optimizing the relative thickness of the under-layer high temperature anti-reflective coating and the top-layer thickness for optimizing optical performance are also disclosed.

Applicability of a Diffuse Reflectance Infrared Fourier Transform handheld spectrometer to perform in situ analyses on Cultural Heritage materials

NASA Astrophysics Data System (ADS)

Arrizabalaga, Iker; Gómez-Laserna, Olivia; Aramendia, Julene; Arana, Gorka; Madariaga, Juan Manuel

2014-08-01

This work studies the applicability of a Diffuse Reflectance Infrared Fourier Transform handheld device to perform in situ analyses on Cultural Heritage assets. This portable diffuse reflectance spectrometer has been used to characterise and diagnose the conservation state of (a) building materials of the Guevara Palace (15th century, Segura, Basque Country, Spain) and (b) different 19th century wallpapers manufactured by the Santa Isabel factory (Vitoria-Gasteiz, Basque Country, Spain) and by the well known Dufour and Leroy manufacturers (Paris, France), all of them belonging to the Torre de los Varona Castle (Villanañe, Basque Country, Spain). In all cases, in situ measurements were carried out and also a few samples were collected and measured in the laboratory by diffuse reflectance spectroscopy (DRIFT) in order to validate the information obtained by the handheld instrument. In the analyses performed in situ, distortions in the diffuse reflectance spectra can be observed due to the presence of specular reflection, showing the inverted bands caused by the Reststrahlen effect, in particular on those IR bands with the highest absorption coefficients. This paper concludes that the results obtained in situ by a diffuse reflectance handheld device are comparable to those obtained with laboratory diffuse reflectance spectroscopy equipment and proposes a few guidelines to acquire good spectra in the field, minimising the influence caused by the specular reflection.

Influence of target reflection on three-dimensional range gated reconstruction.

PubMed

Chua, Sing Yee; Wang, Xin; Guo, Ningqun; Tan, Ching Seong

2016-08-20

The range gated technique is a promising laser ranging method that is widely used in different fields such as surveillance, industry, and military. In a range gated system, a reflected laser pulse returned from the target scene contains key information for range reconstruction, which directly affects the system performance. Therefore, it is necessary to study the characteristics and effects of the target reflection factor. In this paper, theoretical and experimental analyses are performed to investigate the influence of target reflection on three-dimensional (3D) range gated reconstruction. Based on laser detection and ranging (LADAR) and bidirectional reflection distribution function (BRDF) theory, a 3D range gated reconstruction model is derived and the effect on range accuracy is analyzed from the perspectives of target surface reflectivity and angle of laser incidence. Our theoretical and experimental study shows that the range accuracy is proportional to the target surface reflectivity, but it decreases when the angle of incidence increases to adhere to the BRDF model. The presented findings establish a comprehensive understanding of target reflection in 3D range gated reconstruction, which is of interest to various applications such as target recognition and object modeling. This paper provides a reference for future improvement to perform accurate range compensation or correction.

Estimation of reflectance from camera responses by the regularized local linear model.

PubMed

Zhang, Wei-Feng; Tang, Gongguo; Dai, Dao-Qing; Nehorai, Arye

2011-10-01

Because of the limited approximation capability of using fixed basis functions, the performance of reflectance estimation obtained by traditional linear models will not be optimal. We propose an approach based on the regularized local linear model. Our approach performs efficiently and knowledge of the spectral power distribution of the illuminant and the spectral sensitivities of the camera is not needed. Experimental results show that the proposed method performs better than some well-known methods in terms of both reflectance error and colorimetric error. © 2011 Optical Society of America

Reflectance Spectroscopy | Photovoltaic Research | NREL

Science.gov Websites

Reflectance Spectroscopy Reflectance Spectroscopy In a fraction of a second, the photovoltaic (PV metallization properties. PV Research Other Measurements pages: Device Performance Analytical Microscopy & directly normal. The reflectance measurement uses a principle of reciprocity Schematic of the PV

The measured study of natural weathering performance of reflective thermal insulation coating in hot-summer and warm-winter region

NASA Astrophysics Data System (ADS)

Xia, Zhao; Dafu, Weng; Jie, Gu; Binbin, Li

2017-11-01

In order to study the attenuation performance of solar direct reflectance of reflective thermal insulation coating under natural weathering, we conducted a measured study on five coatings with the built natural weathering platform. After the 18-month natural weathering experiments, the color of coating templets turn undertint or black with coating layer pulverized and fallen off, some of the templets starting to crack, fall off and go mouldy. Meanwhile, the reflectance ratio of reflective thermal insulation coating decreased significantly after 3 to 6 months, the degree of attenuation of the five templets is 2% to 28%. After 18 months’ exposure to the blazing sun, the most significant degree of attenuation reached 46%. The solar direct reflectance of coating templet of the same brand remained high as before after natural weathering with an initial high solar direct reflectance

Planar Reflection of Detonations Waves

NASA Astrophysics Data System (ADS)

Damazo, Jason; Shepherd, Joseph

2012-11-01

An experimental study examining normally reflected gaseous detonation waves is undertaken so that the physics of reflected detonations may be understood. Focused schlieren visualization is used to describe the boundary layer development behind the incident detonation wave and the nature of the reflected shock wave. Reflected shock wave bifurcation-which has received extensive study as it pertains to shock tube performance-is predicted by classical bifurcation theory, but is not observed in the present study for undiluted hydrogen-oxygen and ethylene-oxygen detonation waves. Pressure and thermocouple gauges are installed in the floor of the detonation tube so as to examine both the wall pressure and heat flux. From the pressure results, we observe an inconsistency between the measured reflected shock speed and the measured reflected shock strength with one dimensional flow predictions confirming earlier experiments performed in our laboratory. This research is sponsored by the DHS through the University of Rhode Island, Center of Excellence for Explosives Detection.

Self-reflection and academic performance: is there a relationship?

PubMed

Lew, Magdeleine D N; Schmidt, Henk G

2011-10-01

The purposes of the present study were two-fold: first, to evaluate whether reflection journal writing was effective in promoting self-reflection and learning, and whether students become better at self-reflection if they engage continuously in reflection journal writing. To that end, the reflection journals of 690 first-year applied science students at a local polytechnic were studied by means of an automated coding procedures using software. Data was collected twice, once at the beginning and again towards the end of an academic year. Outcomes of the textual content analyses revealed that students reflected on both the process and contents of their learning: critical review of past learning experiences, learning strategies and summaries of what was learned. Correlational analyses showed weak to moderate inter-relationships between the textual categories and their classroom and knowledge acquisition test grades. Taken together, the findings suggest that self-reflection on both how and what students have learned does lead to improvements in academic performance, although to a limited extent.

Singer's preferred acoustic condition in performance in an opera house and self-perception of the singer's voice

NASA Astrophysics Data System (ADS)

Noson, Dennis; Kato, Kosuke; Ando, Yoichi

2004-05-01

Solo singers have been shown to over estimate the relative sound pressure level of a delayed, external reproduction of their own voice, singing single syllables, which, in turn, appears to influence the preferred delay of simulated stage reflections [Noson, Ph.D. thesis, Kobe University, 2003]. Bone conduction is thought to be one factor separating singer versus instrumental performer judgments of stage acoustics. Using a parameter derived from the vocal signal autocorrelation function (ACF envelope), the changes in singer preference for delayed reflections is primarily explained by the ACF parameter, rather than internal bone conduction. An auditory model of a singer's preferred reflection delay is proposed, combining the effects of acoustical environment (reflection amplitude), bone conduction, and performer vocal overestimate, which may be applied to the acoustic design of reflecting elements in both upstage and forestage environments of opera stages. For example, soloists who characteristically underestimate external voice levels (or overestimate their own voice) should be provided shorter distances to reflective panels-irrespective of their singing style. Adjustable elements can be deployed to adapt opera houses intended for bel canto style performances to other styles. Additional examples will also be discussed. a)Now at Kumamoto Univ., Kumamoto, Japan. b)Now at: 1-10-27 Yamano Kami, Kumamoto, Japan.

Sticky Assessments--The Impact of Teachers' Grading Standard on Pupils' School Performance

ERIC Educational Resources Information Center

Keller, Tamás

2016-01-01

This paper argues that school grades cannot be interpreted solely as a reward for a given school performance, since they also reflect teachers' assessments of pupils. A teacher's evaluation of a pupil's performance, as reflected in the grade awarded, might influence the effort that the pupil invests in learning. Grades might therefore serve as…

Reflection/suppression coatings for 900 - 1200 A radiation

NASA Technical Reports Server (NTRS)

Edelstein, Jerry

1989-01-01

The design and performance of multiple-layer, selective-reflection, selective-suppression coatings for the 900 - 1200 A band are described. These coatings are designed to optimize both high reflectivity at a desirable wavelength and low reflectivity at an undesirable wavelength. The minimum structure for a selective coating consists of a thin metal or metal oxide layer (50 - 150 A thickness) over an aluminum substrate protected with a semi-transparent dielectric (100 - 1000 A thickness). Predicted coating performance is strongly effected by varying the layer combination and thickness. A graphical method of optimizing the coating layer structure is developed. Aluminum, silicon, their oxides, and gold have been investigated as coating layer materials. A very simple coating with a 1026 to 1216 A reflectivity ratio greater than 100 was fabricated. Such reflection/suppression coatings may be of great utility to spaceborne EUV spectrographs.

Applicability of a Diffuse Reflectance Infrared Fourier Transform handheld spectrometer to perform in situ analyses on Cultural Heritage materials.

PubMed

Arrizabalaga, Iker; Gómez-Laserna, Olivia; Aramendia, Julene; Arana, Gorka; Madariaga, Juan Manuel

2014-08-14

This work studies the applicability of a Diffuse Reflectance Infrared Fourier Transform handheld device to perform in situ analyses on Cultural Heritage assets. This portable diffuse reflectance spectrometer has been used to characterise and diagnose the conservation state of (a) building materials of the Guevara Palace (15th century, Segura, Basque Country, Spain) and (b) different 19th century wallpapers manufactured by the Santa Isabel factory (Vitoria-Gasteiz, Basque Country, Spain) and by the well known Dufour and Leroy manufacturers (Paris, France), all of them belonging to the Torre de los Varona Castle (Villanañe, Basque Country, Spain). In all cases, in situ measurements were carried out and also a few samples were collected and measured in the laboratory by diffuse reflectance spectroscopy (DRIFT) in order to validate the information obtained by the handheld instrument. In the analyses performed in situ, distortions in the diffuse reflectance spectra can be observed due to the presence of specular reflection, showing the inverted bands caused by the Reststrahlen effect, in particular on those IR bands with the highest absorption coefficients. This paper concludes that the results obtained in situ by a diffuse reflectance handheld device are comparable to those obtained with laboratory diffuse reflectance spectroscopy equipment and proposes a few guidelines to acquire good spectra in the field, minimising the influence caused by the specular reflection. Copyright © 2014 Elsevier B.V. All rights reserved.

An analysis of reflective writing early in the medical curriculum: The relationship between reflective capacity and academic achievement.

PubMed

Ottenberg, Abigale L; Pasalic, Dario; Bui, Gloria T; Pawlina, Wojciech

2016-07-01

To examine the relationship between reflection, gender, residency choice, word count, and academic achievement among medical students. A modified version of the Reflection Evaluation for Learners' Enhanced Competencies Tool (REFLECT) was developed and used for this study (Cronbach's alpha of 0.86 with an intraclass correlation coefficient [ICC] of 0.68). This was applied to writing samples about professionalism in gross anatomy from first-year medical students between 2005 and 2011. Four analysts reviewed and scored written reflections independently. Composite reflection scores were compared with gender, residency choice, length of written reflection, NBME® Gross Anatomy and Embryology Subject Examination scores, and final gross anatomy course. Total of 319 written reflections were evaluated. Female students who pursued medicine specialties had the highest composite reflection scores (87 [27.2%]). Word count frequently correlated with reflection score (p < 0.0001). Students who performed well on the NBME® Gross Anatomy and Embryology Subject Examination tended to achieve high anatomy course grades (p < 0.0001). There was no statistically significant relationship between composite reflection scores and NBME® Gross Anatomy and Embryology Subject Examination scores (p = 0.16) or anatomy course grades (p = 0.90). This study suggests there are likely no correlations between reflective capacity and academic performance on tests of medical knowledge administered early in the medical curriculum.

Quantifying Errors in Jet Noise Research Due to Microphone Support Reflection

NASA Technical Reports Server (NTRS)

Nallasamy, Nambi; Bridges, James

2002-01-01

The reflection coefficient of a microphone support structure used insist noise testing is documented through tests performed in the anechoic AeroAcoustic Propulsion Laboratory. The tests involve the acquisition of acoustic data from a microphone mounted in the support structure while noise is generated from a known broadband source. The ratio of reflected signal amplitude to the original signal amplitude is determined by performing an auto-correlation function on the data. The documentation of the reflection coefficients is one component of the validation of jet noise data acquired using the given microphone support structure. Finally. two forms of acoustic material were applied to the microphone support structure to determine their effectiveness in reducing reflections which give rise to bias errors in the microphone measurements.

A millimeter-wave reflection-beam isolator

NASA Technical Reports Server (NTRS)

Kanda, M.; May, W. G.

1975-01-01

A new and simple type of millimeter-wave isolator using a solid-state magnetoplasma in a reflection-beam system is described. Some data are presented showing performance at 94 GHz. Practical considerations indicate that performance should be much closer to ideal at higher frequencies.

Predicting change in epistemological beliefs, reflective thinking and learning styles: a longitudinal study.

PubMed

Phan, Huy P

2008-03-01

Although extensive research has examined epistemological beliefs, reflective thinking and learning approaches, very few studies have looked at these three theoretical frameworks in their totality. This research tested two separate structural models of epistemological beliefs, learning approaches, reflective thinking and academic performance among tertiary students over a period of 12 months. Participants were first-year Arts (N=616; 271 females, 345 males) and second-year Mathematics (N=581; 241 females, 341 males) university students. Students' epistemological beliefs were measured with the Schommer epistemological questionnaire (EQ, Schommer, 1990). Reflective thinking was measured with the reflective thinking questionnaire (RTQ, Kember et al., 2000). Student learning approaches were measured with the revised study process questionnaire (R-SPQ-2F, Biggs, Kember, & Leung, 2001). LISREL 8 was used to test two structural equation models - the cross-lag model and the causal-mediating model. In the cross-lag model involving Arts students, structural equation modelling showed that epistemological beliefs influenced student learning approaches rather than the contrary. In the causal-mediating model involving Mathematics students, the results indicate that both epistemological beliefs and learning approaches predicted reflective thinking and academic performance. Furthermore, learning approaches mediated the effect of epistemological beliefs on reflective thinking and academic performance. Results of this study are significant as they integrated the three theoretical frameworks within the one study.

Reflection as a component of formative assessment appears to be instrumental in promoting the use of feedback; an observational study.

PubMed

Pelgrim, E A M; Kramer, A W M; Mokkink, H G A; van der Vleuten, C P M

2013-09-01

Although the literature suggests that reflection has a positive impact on learning, there is a paucity of evidence to support this notion. We investigated feedback and reflection in relation to the likelihood that feedback will be used to inform action plans. We hypothesised that feedback and reflection present a cumulative sequence (i.e. trainers only pay attention to trainees' reflections when they provided specific feedback) and we hypothesised a supplementary effect of reflection. We analysed copies of assessment forms containing trainees' reflections and trainers' feedback on observed clinical performance. We determined whether the response patterns revealed cumulative sequences in line with the Guttman scale. We further examined the relationship between reflection, feedback and the mean number of specific comments related to an action plan (ANOVA) and we calculated two effect sizes. Both hypotheses were confirmed by the results. The response pattern found showed an almost perfect fit with the Guttman scale (0.99) and reflection seems to have supplementary effect on the variable action plan. Reflection only occurs when a trainer has provided specific feedback; trainees who reflect on their performance are more likely to make use of feedback. These results confirm findings and suggestions reported in the literature.

Effect of a chamber orchestra on direct sound and early reflections for performers on stage: A boundary element method study.

PubMed

Panton, Lilyan; Holloway, Damien; Cabrera, Densil

2017-04-01

Early reflections are known to be important to musicians performing on stage, but acoustic measurements are usually made on empty stages. This work investigates how a chamber orchestra setup on stage affects early reflections from the stage enclosure. A boundary element method (BEM) model of a chamber orchestra is validated against full scale measurements with seated and standing subjects in an anechoic chamber and against auditorium measurements, demonstrating that the BEM simulation gives realistic results. Using the validated BEM model, an investigation of how a chamber orchestra attenuates and scatters both the direct sound and the first-order reflections is presented for two different sized "shoe-box" stage enclosures. The first-order reflections from the stage are investigated individually: at and above the 250 Hz band, horizontal reflections from stage walls are attenuated to varying degrees, while the ceiling reflection is relatively unaffected. Considering the overall effect of the chamber orchestra on the direct sound and first-order reflections, differences of 2-5 dB occur in the 1000 Hz octave band when the ceiling reflection is excluded (slightly reduced when including the unobstructed ceiling reflection). A tilted side wall case showed the orchestra has a reduced effect with a small elevation of the lateral reflections.

Impact of Automated Software Testing Tools on Reflective Thinking and Student Performance in Introductory Computer Science Programming Classes

ERIC Educational Resources Information Center

Fridge, Evorell; Bagui, Sikha

2016-01-01

The goal of this research was to investigate the effects of automated testing software on levels of student reflection and student performance. This was a self-selecting, between subjects design that examined the performance of students in introductory computer programming classes. Participants were given the option of using the Web-CAT…

Cost effective prevention of reflective cracking of composite pavement.

DOT National Transportation Integrated Search

2011-09-01

Louisiana experimented with various techniques and treatments to control reflective cracking since the : 1970s. The objective of this study is to evaluate and compare different reflective cracking control : treatments by evaluating the performance, c...

Very High Reflectivity Supermirrors And Their Applications

NASA Astrophysics Data System (ADS)

Mezei, F.

1989-01-01

Very high reflectivity (some 95 % or better) supermirrors, with cut-off angles up to 2 times the critical angle of Ni coated simple total reflection neutron mirrors, can be produced using well established conventional deposition techniques. This performance makes applications involving multiple reflections and transmission geometries feasible, which in turn allow us to use more sophisticated neutron optical systems in order to optimize performance and minimize the amount a scarce supermirrors required. A key feature of several of these novel systems is the distribution of tasks between the several optical components achieving the desired performance by multiple action. The design and characteristics of a series of novel applications, such as polarizing cavities, collimators and guides, non-polarizing guides, beam compressors, deflectors and splitters (most of them tested or being implemented) are the main subjects of the present paper.

Mach stem formation in reflection and focusing of weak shock acoustic pulses.

PubMed

Karzova, Maria M; Khokhlova, Vera A; Salze, Edouard; Ollivier, Sébastien; Blanc-Benon, Philippe

2015-06-01

The aim of this study is to show the evidence of Mach stem formation for very weak shock waves with acoustic Mach numbers on the order of 10(-3) to 10(-2). Two representative cases are considered: reflection of shock pulses from a rigid surface and focusing of nonlinear acoustic beams. Reflection experiments are performed in air using spark-generated shock pulses. Shock fronts are visualized using a schlieren system. Both regular and irregular types of reflection are observed. Numerical simulations are performed to demonstrate the Mach stem formation in the focal region of periodic and pulsed nonlinear beams in water.

Crystals and collimators for X-ray spectrometry. [Bragg reflection properties and design for astronomical applications

NASA Technical Reports Server (NTRS)

Mckenzie, D. L.; Landecker, P. B.; Underwood, J. H.

1976-01-01

Results of the measurement of Bragg reflection properties of crystals suitable for use in X-ray astronomy are presented. Measurements with a double crystal spectrometer were performed on rubidium acid phthalate and thallium acid phthalate to yield values of the integrated reflectivity and diffraction width in the range 8-18 A, and measurements of integrated reflectivity were also performed on ammonium dihydrogen phosphate. The theory and design of an arc-minute range multigrid collimator to be flown on a rocket for solar X-ray studies are also described, along with a method for determining the collimator's X-ray axis.

Using Brain Imaging to Extract the Structure of Complex Events at the Rational Time Band

PubMed Central

Anderson, John R.; Qin, Yulin

2017-01-01

A functional magnetic resonance imaging (fMRI) study was performed in which participants performed a complex series of mental calculations that spanned about 2 min. An Adaptive Control of Thought—Rational (ACT-R) model [Anderson, J. R. How can the human mind occur in the physical universe? New York: Oxford University Press, 2007] was developed that successfully fit the distribution of latencies. This model generated predictions for the fMRI signal in six brain regions that have been associated with modules in the ACT-R theory. The model’s predictions were confirmed for a fusiform region that reflects the visual module, for a prefrontal region that reflects the retrieval module, and for an anterior cingulate region that reflects the goal module. In addition, the only significant deviations to the motor region that reflects the manual module were anticipatory hand movements. In contrast, the predictions were relatively poor for a parietal region that reflects an imaginal module and for a caudate region that reflects the procedural module. Possible explanations of these poor fits are discussed. In addition, exploratory analyses were performed to find regions that might correspond to the predictions of the modules. PMID:18345979

Using brain imaging to extract the structure of complex events at the rational time band.

PubMed

Anderson, John R; Qin, Yulin

2008-09-01

A functional magnetic resonance imaging (fMRI) study was performed in which participants performed a complex series of mental calculations that spanned about 2 min. An Adaptive Control of Thought--Rational (ACT-R) model [Anderson, J. R. How can the human mind occur in the physical universe? New York: Oxford University Press, 2007] was developed that successfully fit the distribution of latencies. This model generated predictions for the fMRI signal in six brain regions that have been associated with modules in the ACT-R theory. The model's predictions were confirmed for a fusiform region that reflects the visual module, for a prefrontal region that reflects the retrieval module, and for an anterior cingulate region that reflects the goal module. In addition, the only significant deviations to the motor region that reflects the manual module were anticipatory hand movements. In contrast, the predictions were relatively poor for a parietal region that reflects an imaginal module and for a caudate region that reflects the procedural module. Possible explanations of these poor fits are discussed. In addition, exploratory analyses were performed to find regions that might correspond to the predictions of the modules.

Illumination discrimination in the absence of a fixed surface-reflectance layout

PubMed Central

Radonjić, Ana; Ding, Xiaomao; Krieger, Avery; Aston, Stacey; Hurlbert, Anya C.; Brainard, David H.

2018-01-01

Previous studies have shown that humans can discriminate spectral changes in illumination and that this sensitivity depends both on the chromatic direction of the illumination change and on the ensemble of surfaces in the scene. These studies, however, always used stimulus scenes with a fixed surface-reflectance layout. Here we compared illumination discrimination for scenes in which the surface reflectance layout remains fixed (fixed-surfaces condition) to those in which surface reflectances were shuffled randomly across scenes, but with the mean scene reflectance held approximately constant (shuffled-surfaces condition). Illumination discrimination thresholds in the fixed-surfaces condition were commensurate with previous reports. Thresholds in the shuffled-surfaces condition, however, were considerably elevated. Nonetheless, performance in the shuffled-surfaces condition exceeded that attainable through random guessing. Analysis of eye fixations revealed that in the fixed-surfaces condition, low illumination discrimination thresholds (across observers) were predicted by low overall fixation spread and high consistency of fixation location and fixated surface reflectances across trial intervals. Performance in the shuffled-surfaces condition was not systematically related to any of the eye-fixation characteristics we examined for that condition, but was correlated with performance in the fixed-surfaces condition. PMID:29904786

Analyzing the performance of PROSPECT model inversion based on different spectral information for leaf biochemical properties retrieval

NASA Astrophysics Data System (ADS)

Sun, Jia; Shi, Shuo; Yang, Jian; Du, Lin; Gong, Wei; Chen, Biwu; Song, Shalei

2018-01-01

Leaf biochemical constituents provide useful information about major ecological processes. As a fast and nondestructive method, remote sensing techniques are critical to reflect leaf biochemistry via models. PROSPECT model has been widely applied in retrieving leaf traits by providing hemispherical reflectance and transmittance. However, the process of measuring both reflectance and transmittance can be time-consuming and laborious. Contrary to use reflectance spectrum alone in PROSPECT model inversion, which has been adopted by many researchers, this study proposes to use transmission spectrum alone, with the increasing availability of the latter through various remote sensing techniques. Then we analyzed the performance of PROSPECT model inversion with (1) only transmission spectrum, (2) only reflectance and (3) both reflectance and transmittance, using synthetic datasets (with varying levels of random noise and systematic noise) and two experimental datasets (LOPEX and ANGERS). The results show that (1) PROSPECT-5 model inversion based solely on transmission spectrum is viable with results generally better than that based solely on reflectance spectrum; (2) leaf dry matter can be better estimated using only transmittance or reflectance than with both reflectance and transmittance spectra.

Reflector Technology Development and System Design for Concentrating Solar Power Technologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adam Schaut

2011-12-30

Alcoa began this program in March of 2008 with the goal of developing and validating an advanced CSP trough design to lower the levelized cost of energy (LCOE) as compared to existing glass based, space-frame trough technology. In addition to showing a pathway to a significant LCOE reduction, Alcoa also desired to create US jobs to support the emerging CSP industry. Alcoa's objective during Phase I: Concept Feasibility was to provide the DOE with a design approach that demonstrates significant overall system cost savings without sacrificing performance. Phase I consisted of two major tasks; reflector surface development and system conceptmore » development. Two specific reflective surface technologies were investigated, silver metallized lamination, and thin film deposition both applied on an aluminum substrate. Alcoa prepared samples; performed test validation internally; and provided samples to the NREL for full-spectrum reflectivity measurements. The final objective was to report reflectivity at t = 0 and the latest durability results as of the completion of Phase 1. The target criteria for reflectance and durability were as follows: (1) initial (t = 0), hemispherical reflectance >93%, (2) initial spectral reflectance >90% for 25-mrad reading and >87% for 7-mrad reading, and (3) predicted 20 year durability of less than 5% optical performance drop. While the results of the reflective development activities were promising, Alcoa was unable to down-select on a reflective technology that met the target criteria. Given the progress and potential of both silver film and thin film technologies, Alcoa continued reflector surface development activities in Phase II. The Phase I concept development activities began with acquiring baseline CSP system information from both CSP Services and the DOE. This information was used as the basis to develop conceptual designs through ideation sessions. The concepts were evaluated based on estimated cost and high-level structural performance. The target criteria for the concept development was to achieve a solar field cost savings of 25%-50% thereby meeting or exceeding the DOE solar field cost savings target of $350/m2. After evaluating various structural design approaches, Alcoa down-selected to a monocoque, dubbed Wing Box, design that utilizes the reflective surface as a structural, load carrying member. The cost and performance potential of the Wing Box concept was developed via initial finite element analysis (FEA) and cost modeling. The structural members were sized through material utilization modeling when subjected to representative loading conditions including wind loading. Cost modeling was utilized to refine potential manufacturing techniques that could be employed to manufacture the structural members. Alcoa concluded that an aluminum intensive collector design can achieve significant cost savings without sacrificing performance. Based on the cost saving potential of this Concept Feasibility study, Alcoa recommended further validation of this CSP approach through the execution of Phase II: Design and Prototype Development. Alcoa Phase II objective was to provide the DOE with a validated CSP trough design that demonstrates significant overall system cost savings without sacrificing performance. Phase II consisted of three major tasks; Detail System Design, Prototype Build, and System Validation. Additionally, the reflector surface development that began in Phase I was continued in Phase II. After further development work, Alcoa was unable to develop a reflective technology that demonstrated significant performance or cost benefits compared to commercially available CSP reflective products. After considering other commercially available reflective surfaces, Alcoa selected Alano's MIRO-SUN product for use on the full scale prototype. Although MIRO-SUN has a lower specular reflectivity compared to other options, its durability in terms of handling, cleaning, and long-term reflectivity was deemed the most important attribute to successfully validate Alcoa's advanced trough architecture. To validate the performance of the Wing Box trough, a 6 meter aperture by 14 meter long prototype trough was built. For ease of shipping to and assembly at NREL's test facility, the prototype was fabricated in two half modules and joined along the centerline to create the Wing Box trough. The trough components were designed to achieve high precision of the reflective surface while leveraging high volume manufacturing and assembly techniques.« less

Focus on the Now: Making Time for Reflection-in-Action during Teacher Response

ERIC Educational Resources Information Center

Edgington, Anthony

2009-01-01

In this article, the author discusses the importance of incorporating more methods that promote reflection-in-action--or reflecting on the immediate thoughts and reactions that a person has while performing an act, the time "during which one can still make a difference to the situation at hand"--into response situations. Reflection is something…

Reflections From a Fresnel Lens

ERIC Educational Resources Information Center

Keeports, David

2005-01-01

Reflection of light by a convex Fresnel lens gives rise to two distinct images. A highly convex inverted real reflective image forms on the object side of the lens, while an upright virtual reflective image forms on the opposite side of the lens. I describe here a set of laser experiments performed upon a Fresnel lens. These experiments provide…

Removing Our Masks: Using the Visual and Performing Arts to Promote Deep Reflection in Pre-Service Teachers

ERIC Educational Resources Information Center

McHattan, Patty Alvarez; McCray, Erica D.

2009-01-01

The role of reflection is central to teacher preparation. As individuals integrate new information within their existing schema, they refine their practice. Through reflection pre-service teachers examine, evaluate, and adjust. Yet, the practice of reflection is rarely explicitly taught. Often teacher educators found their students aligning their…

The Reflecting Brain: Reflection Competence in an Educational Setting Is Associated with Increased Electroencephalogram Activity in the Alpha Band

ERIC Educational Resources Information Center

Rominger, Christian; Reitinger, Johannes; Seyfried, Clemens; Schneckenleitner, Eva; Fink, Andreas

2017-01-01

Teachers' ability to critically reflect classroom situations in relation to their own actions constitutes an important prerequisite to improve teaching performance and professional behavior. This study investigated electroencephalogram activity in the alpha band during a reflection task before and after training in a sample of preservice teachers.…

Reflected wave manipulation by inhomogeneous impedance via varying-depth acoustic liners

NASA Astrophysics Data System (ADS)

Guo, Jingwen; Zhang, Xin; Fang, Yi; Fattah, Ryu

2018-05-01

Acoustic liners, consisting of a perforated panel affixed to a honeycomb core with a rigid back plate, are widely used for noise attenuation purpose. In this study, by exploiting inhomogeneous impedance properties, we report an experimental and numerical study on a liner-type acoustic metasurface, which possesses the functionality of both reflected wave manipulation and sound energy attenuation simultaneously. To realize the inhomogeneous acoustic impedance, an acoustic metasurface constructed by varying-depth acoustic liners is designed and fabricated. The reflected sound pressure fields induced by the metasurface are obtained in both experiments and simulations. A complete characterization of this metasurface is performed, including the effects of depth gradient, incident angle, and incident frequency. Anomalous reflection, apparent negative reflection, and conversion from an incident wave to a surface wave with strong energy dissipation are achieved by the structure. Moreover, our proposed structure can overcome the single frequency performance limitation that exists in conventional metasurfaces and performs well in a broadband frequency range. The proposed acoustic metasurface offers flexibility in controlling the direction of sound wave propagation with energy dissipation property and holds promise for various applications of noise reduction.

Neutron reflecting supermirror structure

DOEpatents

Wood, J.L.

1992-12-01

An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources. 2 figs.

Neutron reflecting supermirror structure

DOEpatents

Wood, James L.

1992-01-01

An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources.

Reflective Practice in Group Co-Leadership

ERIC Educational Resources Information Center

Okech, Jane E. Atieno

2008-01-01

Group literature on co-leaders' experiences and perceptions while leading groups illuminate reflective practice as highly influential to co-leader relationships and performances. Using practical examples grounded by interdisciplinary literature on reflective practice, this article explores and expands dialogue on the complex interplay between…

In-vivo Reflectance Measurements from Human Skin

NASA Astrophysics Data System (ADS)

Delgado, J. A.; Cornejo, A.; Cunill, M.; Báez, J. J.; Matos, R.; Anasagasti, L.; Santiago, C.

2006-09-01

We evaluate the potential of using a standard commercial spectrophotometer, specifically designed to meet the growing requirement for color control in the digital-imaging application field, to perform in-vivo diffuse reflectance measurements from adult human skin. We report and discuss diffuse reflectance spectra for three practical situations: a) reflectance versus skin type, b) reflectance from normal skin with different grade of solar exposition, c) reflectance from normal skin versus reflectance from seborrheic keratosis. Results show, that using the above spectrophotometer we can easily differentiate two sites of different solar exposition. Besides, significant differences are found in the normal skin diffuse reflectance for patients with different skin types.

A suspended act: increased reflectivity and gender-dependent electrophysiological change following Quadrato Motor Training.

PubMed

Ben-Soussan, Tal Dotan; Berkovich-Ohana, Aviva; Glicksohn, Joseph; Goldstein, Abraham

2014-01-01

Quadrato Motor Training (QMT) is a specifically-structured walking meditation, aimed at improving reflectivity and lowering habitual thought and movement. Here we set out to examine the possible effect of QMT on reflectivity, employing the Hidden Figures Test (HFT), which assesses both spatial performance (measured by correct answers) as well as reflectivity (interpolated from correct answers and reaction time). In the first study (n = 24, only females), we showed that QMT significantly improves HFT performance, compared to two groups, controlling for cognitive or motor aspects of the QMT: Verbal Training (identical cognitive training with verbal response) and Simple Motor Training (similar motor training with reduced choice requirements). These results show that QMT improves HFT performance above the pre-post expected learning. In the second study, building on previous literature showing gender-dependent effects on cognitive performance, we conducted a preliminary pilot examining gender-dependent effect of training on reflectivity and its electrophysiological counterparts. EEG analyses focused on theta, alpha and gamma coherence. HFT performance and resting-state EEG were measured in 37 participants (20 males), using a within-subject pre-post design. Following training, HFT performance improved in both genders. However, we found a gender-dependent difference in functional connectivity: while theta and alpha intra-hemispheric coherence was enhanced in females, the opposite pattern was found in males. These results are discussed in relation to neuronal efficiency theory. Together, the results demonstrate that QMT improves spatial performance, and may involve a gender-dependent electrophysiological effect. This study emphasizes both the importance of studying gender-related training effects within the contemplative neuroscience endeavor, as well as the need to widen its scope toward including "contemplation in action."

A new scheme of force reflecting control

NASA Technical Reports Server (NTRS)

Kim, Won S.

1992-01-01

A new scheme of force reflecting control has been developed that incorporates position-error-based force reflection and robot compliance control. The operator is provided with a kinesthetic force feedback which is proportional to the position error between the operator-commanded and the actual position of the robot arm. Robot compliance control, which increases the effective compliance of the robot, is implemented by low pass filtering the outputs of the force/torque sensor mounted on the base of robot hand and using these signals to alter the operator's position command. This position-error-based force reflection scheme combined with shared compliance control has been implemented successfully to the Advanced Teleoperation system consisting of dissimilar master-slave arms. Stability measurements have demonstrated unprecedentedly high force reflection gains of up to 2 or 3, even though the slave arm is much stiffer than operator's hand holding the force reflecting hand controller. Peg-in-hole experiments were performed with eight different operating modes to evaluate the new force-reflecting control scheme. Best task performance resulted with this new control scheme.

Transient high frequency signal estimation: A model-based processing approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barnes, F.L.

1985-03-22

By utilizing the superposition property of linear systems a method of estimating the incident signal from reflective nondispersive data is developed. One of the basic merits of this approach is that, the reflections were removed by direct application of a Weiner type estimation algorithm, after the appropriate input was synthesized. The structure of the nondispersive signal model is well documented, and thus its' credence is established. The model is stated and more effort is devoted to practical methods of estimating the model parameters. Though a general approach was developed for obtaining the reflection weights, a simpler approach was employed here,more » since a fairly good reflection model is available. The technique essentially consists of calculating ratios of the autocorrelation function at lag zero and that lag where the incident and first reflection coincide. We initially performed our processing procedure on a measurement of a single signal. Multiple application of the processing procedure was required when we applied the reflection removal technique on a measurement containing information from the interaction of two physical phenomena. All processing was performed using SIG, an interactive signal processing package. One of the many consequences of using SIG was that repetitive operations were, for the most part, automated. A custom menu was designed to perform the deconvolution process.« less

Students Reflecting on Test Performance and Feedback: An On-Line Approach

ERIC Educational Resources Information Center

Fyfe, Georgina; Fyfe, Sue; Meyer, Jan; Ziman, Mel; Sanders, Kathy; Hill, Julie

2014-01-01

Undergraduate students accessing on-line tests in Human Biology in three Western Australian universities were asked to complete an on-line post-test reflective survey about their perceptions of their test performance in light of automated feedback. The survey allowed pre-determined choices and comment text boxes relating to students' perceptions…

Students' Performance in Geometrical Reflection Using GeoGebra

ERIC Educational Resources Information Center

Seloraji, Pavethira; Eu, Leong Kwan

2017-01-01

Students in this era need to grasp the concept of geometry instead of memorizing formulae. This is important for them to further their knowledge in geometry. The purpose of the research was to determine whether GeoGebra software influences year one students' performance in geometrical reflection. The research utilized an experimental research…

Sex Differences in Examination Performance: Do These Reflect Differences in Ability or Sex-Role Stereotypes?

ERIC Educational Resources Information Center

Murphy, Roger J. L.

1978-01-01

Sex differences in GCE 'O' level examination performance are reflected both in the number of boys and girls entering for different subjects and in the numbers obtaining the higher grades. From a review of possible factors, it seems that sex-role stereotyping is the most influential. (Author/SJL)

Health Education Field Experience Stories: A Reflective, Digital, Performance-Based Project

ERIC Educational Resources Information Center

Lyde, Adrian R.

2012-01-01

This article describes a reflective, systematic, performance-based project resulting in the development of a digital story about a community health education field experience. The project is designed for preservice health education students at the college/university level. The primary benefit of the project is that it challenges students to engage…

Sometimes-Competing Retrieval (SOCR): A Formalization of the Comparator Hypothesis

ERIC Educational Resources Information Center

Stout, Steven C.; Miller, Ralph R.

2007-01-01

Cue competition is one of the most studied phenomena in associative learning. However, a theoretical disagreement has long stood over whether it reflects a learning or performance deficit. The comparator hypothesis, a model of expression of Pavlovian associations, posits that learning is not subject to competition but that performance reflects a…

Structured self-reflection as a tool to enhance perceived performance and maintain effort in adult recreational salsa dancers

USDA-ARS?s Scientific Manuscript database

The purpose of this study was to determine if the use of structured self-reflection in community dance classes would influence achievement goal orientations, levels of intrinsic motivation, or perceived dance performance. The Task and Ego Orientation in Sport Questionnaire (TEOSQ) and the Intrinsic...

Feedback Providing Improvement Strategies and Reflection on Feedback Use: Effects on Students' Writing Motivation, Process, and Performance

ERIC Educational Resources Information Center

Duijnhouwer, Hendrien; Prins, Frans J.; Stokking, Karel M.

2012-01-01

This study investigated the effects of feedback providing improvement strategies and a reflection assignment on students' writing motivation, process, and performance. Students in the experimental feedback condition (n = 41) received feedback including improvement strategies, whereas students in the control feedback condition (n = 41) received…

A three-year reflective writing program as part of introductory pharmacy practice experiences.

PubMed

Nuffer, Wesley; Vaughn, Jessica; Kerr, Kevin; Zielenski, Christopher; Toppel, Brianna; Johnson, Lauren; McCauley, Patrina; Turner, Christopher J

2013-06-12

To implement and evaluate a 3-year reflective writing program incorporated into introductory pharmacy practice experiences (IPPEs) in the first- through third-year of a doctor of pharmacy (PharmD) program. Reflective writing was integrated into 6 IPPE courses to develop students' lifelong learning skills. In their writing, students were required to self-assess their performance in patient care activities, identify and describe how they would incorporate learning opportunities, and then evaluate their progress. Practitioners, faculty members, and fourth-year PharmD students served as writing preceptors. The success of the writing program was assessed by reviewing class performance and surveying writing preceptor's opinions regarding the student's achievement of program objectives. Class pass rates averaged greater than 99% over the 8 years of the program and the large majority of the writing preceptors reported that student learning objectives were met. A support pool of 99 writing preceptors was created. A 3-year reflective writing program improved pharmacy students' reflection and reflective writing skills.

Self-reflection, growth goals, and academic outcomes: A qualitative study.

PubMed

Travers, Cheryl J; Morisano, Dominique; Locke, Edwin A

2015-06-01

Goal-setting theory continues to be among the most popular and influential theories of motivation and performance, although there have been limited academic applications relative to applications in other domains, such as organizational psychology. This paper summarizes existing quantitative research and then employs a qualitative approach to exploring academic growth via an in-depth reflective growth goal-setting methodology. The study focuses on 92 UK final-year students enrolled in an elective advanced interpersonal skills and personal development module, with self-reflection and growth goal setting at its core. Qualitative data in the form of regular reflective written diary entries and qualitative questionnaires were collected from students during, on completion of, and 6 months following the personal growth goal-setting programme. About 20% of students' self-set growth goals directly related to academic growth and performance; students reported that these had a strong impact on their achievement both during and following the reflective programme. Growth goals that were indirectly related to achievement (e.g., stress management) appeared to positively impact academic growth and other outcomes (e.g., well-being). A follow-up survey revealed that growth goal setting continued to impact academic growth factors (e.g., self-efficacy, academic performance) beyond the reflective programme itself. Academic growth can result from both academically direct and indirect growth goals, and growth goal setting appears to be aided by the process of simultaneous growth reflection. The implications for promoting academic growth via this unique learning and development approach are discussed. © 2014 The British Psychological Society.

Amplitude envelope correlations measure synchronous cortical oscillations in performing musicians.

PubMed

Zamm, Anna; Debener, Stefan; Bauer, Anna-Katharina R; Bleichner, Martin G; Demos, Alexander P; Palmer, Caroline

2018-05-14

A major question facing cognitive neuroscience is measurement of interbrain synchrony between individuals performing joint actions. We describe the application of a novel method for measuring musicians' interbrain synchrony: amplitude envelope correlations (AECs). Amplitude envelopes (AEs) reflect energy fluctuations in cortical oscillations over time; AE correlations measure the degree to which two envelope fluctuations are temporally correlated, such as cortical oscillations arising from two individuals performing a joint action. Wireless electroencephalography was recorded from two pianists performing a musical duet; an analysis pipeline is described for computing AEs of cortical oscillations at the duet performance frequency (number of tones produced per second) to test whether these oscillations reflect the temporal dynamics of partners' performances. The pianists' AE correlations were compared with correlations based on a distribution of AEs simulated from white noise signals using the same methods. The AE method was also applied to the temporal characteristics of the pianists' performances, to show that the observed pair's AEs reflect the temporal dynamics of their performance. AE correlations offer a promising approach for assessing interbrain correspondences in cortical activity associated with performing joint tasks. © 2018 New York Academy of Sciences.

University Employment Transitions in International Performing Arts: The Intern's Story

ERIC Educational Resources Information Center

Carneiro, Maria

2013-01-01

This article reflects my journey as a performing arts student and intern both in Portugal and abroad. It is not intended as a personal journal, but rather a reflection and an aftermath comment on my experiences and learning processes. First it provides a context regarding my university education in a Southern European country, against a previous…

Theoretical and experimental analyses of the performance of two-color laser ranging systems

NASA Technical Reports Server (NTRS)

Im, K. E.; Gardner, C. S.

1985-01-01

The statistical properties of the signals reflected from the retroreflector equipped satellites were studied. It is found that coherence interference between pulse reflections from retroreflectors of different ranges on the array platform is the primary cause of signal fluctuations. The performance of a cross-correlation technique to estimate the differential propagation time is analyzed by considering both shot noise and speckle. For the retroreflector arrays, timing performance is dominated by interference induced speckle, and the differential propagation time cannot be resolved to better than the pulse widths of the received signals. The differential timing measurements obtained over a horizontal path are analyzed. The ocean-reflected pulse measurements obtained from the airborne two-color laser altimeter experiment are presented.

Design of an Online Curriculum Promoting Transformative Learning in Post Professional Doctoral Students

ERIC Educational Resources Information Center

Provident, Ingrid; Salls, Joyce; Dolhi, Cathy; Schreiber, Jodi; Mattila, Amy; Eckel, Emily

2015-01-01

Written reflections of 113 occupational therapy clinical doctoral students who graduated from an online program between 2007 and 2013 were analyzed for themes which reflected transformative learning and characteristics of curricular design which promoted transformative learning. Qualitative analyses of written reflections were performed. Several…

What Medical Students Say about Psychiatry: Results of a Reflection Exercise

ERIC Educational Resources Information Center

Brenner, Adam M.

2011-01-01

Objective: The author describes the results of a reflection exercise for psychiatry clerkship students. Method: The author performed a qualitative analysis on 100 "reflection" papers written by medical students in their psychiatry clerkship and identified the most prominent thematic content. Results: The most common thematic content involved…

Nonimaging light concentration using total internal reflection films.

PubMed

Ouellette, G; Waltham, C E; Drees, R M; Poon, A; Schubank, R; Whitehead, L A

1992-05-01

We present a method of fabricating nonimaging light concentrators from total internal reflection film. A prototype has been made and tested and found to operate in agreement with predictions of ray-tracing codes. The performance of the prototype is comparable with that of concentrators made from specular reflecting materials.

Is there agreement between worker self and supervisor assessment of worker safety performance? An examination in the construction industry.

PubMed

Xia, Nini; Griffin, Mark A; Wang, Xueqing; Liu, Xing; Wang, Dan

2018-06-01

Individual safety performance (behavior) critically influences safety outcomes in high-risk workplaces. Compared to the study of generic work performance on different measurements, few studies have investigated different measurements of safety performance, typically relying on employees' self-reflection of their safety behavior. This research aims to address this limitation by including worker self-reflection and other (i.e., supervisor) assessment of two worker safety performance dimensions, safety compliance and safety participation. A sample of 105 workers and 17 supervisors in 17 groups in the Chinese construction industry participated in this study. Comparisons were made between worker compliance and participation in each measurement, and between workers' and supervisors' assessment of workers' compliance and participation. Multilevel modeling was adopted to test the moderating effects on the worker self-reflection and supervisor-assessment relationship by group safety climate and the work experience of supervisors. Higher levels of safety compliance than participation were found for self-reflection and supervisor assessment. The discrepancy between the two measurements in each safety performance dimension was significant. The work experience of supervisors attenuated the discrepancy between self- and supervisor-assessment of compliance. Contrary to our expectations, the moderating effect of group safety climate was not supported. The discrepancy between worker self- and supervisor-assessment of worker safety performance, thus, suggests the importance of including alternative measurements of safety performance in addition to self-reflection. Lower levels of participation behavior in both raters suggest more research on the motivators of participatory behavior. Practical applications The discrepancy between different raters can lead to negative reactions of ratees, suggesting that managers should be aware of that difference. Assigning experienced supervisors as raters can be effective at mitigating interrater discrepancy and conflicts in the assessment of compliance behavior. Copyright © 2018 National Safety Council and Elsevier Ltd. All rights reserved.

Setting performance standards for medical practice: a theoretical framework.

PubMed

Southgate, L; Hays, R B; Norcini, J; Mulholland, H; Ayers, B; Woolliscroft, J; Cusimano, M; McAvoy, P; Ainsworth, M; Haist, S; Campbell, M

2001-05-01

The assessment of performance in the real world of medical practice is now widely accepted as the goal of assessment at the postgraduate level. This is largely a validity issue, as it is recognised that tests of knowledge and in clinical simulations cannot on their own really measure how medical practitioners function in the broader health care system. However, the development of standards for performance-based assessment is not as well understood as in competency assessment, where simulations can more readily reflect narrower issues of knowledge and skills. This paper proposes a theoretical framework for the development of standards that reflect the more complex world in which experienced medical practitioners work. The paper reflects the combined experiences of a group of education researchers and the results of literature searches that included identifying current health system data sources that might contribute information to the measurement of standards. Standards that reflect the complexity of medical practice may best be developed through an "expert systems" analysis of clinical conditions for which desired health care outcomes reflect the contribution of several health professionals within a complex, three-dimensional, contextual model. Examples of the model are provided, but further work is needed to test validity and measurability.

Absorbing boundary layers for spin wave micromagnetics

NASA Astrophysics Data System (ADS)

Venkat, G.; Fangohr, H.; Prabhakar, A.

2018-03-01

Micromagnetic simulations are used to investigate the effects of different absorbing boundary layers (ABLs) on spin waves (SWs) reflected from the edges of a magnetic nano-structure. We define the conditions that a suitable ABL must fulfill and compare the performance of abrupt, linear, polynomial and tan hyperbolic damping profiles in the ABL. We first consider normal incidence in a permalloy stripe and propose a transmission line model to quantify reflections and calculate the loss introduced into the stripe due to the ABL. We find that a parabolic damping profile absorbs the SW energy efficiently and has a low reflection coefficient, thus performing much better than the commonly used abrupt damping profile. We then investigated SWs that are obliquely incident at 26.6 °, 45 ° and 63.4 ° on the edge of a yttrium-iron-garnet film. The parabolic damping profile again performs efficiently by showing a high SW energy transfer to the ABL and a low reflected SW amplitude.

Next-generation fiber lasers enabled by high-performance components

NASA Astrophysics Data System (ADS)

Kliner, D. A. V.; Victor, B.; Rivera, C.; Fanning, G.; Balsley, D.; Farrow, R. L.; Kennedy, K.; Hampton, S.; Hawke, R.; Soukup, E.; Reynolds, M.; Hodges, A.; Emery, J.; Brown, A.; Almonte, K.; Nelson, M.; Foley, B.; Dawson, D.; Hemenway, D. M.; Urbanek, W.; DeVito, M.; Bao, L.; Koponen, J.; Gross, K.

2018-02-01

Next-generation industrial fiber lasers enable challenging applications that cannot be addressed with legacy fiber lasers. Key features of next-generation fiber lasers include robust back-reflection protection, high power stability, wide power tunability, high-speed modulation and waveform generation, and facile field serviceability. These capabilities are enabled by high-performance components, particularly pump diodes and optical fibers, and by advanced fiber laser designs. We summarize the performance and reliability of nLIGHT diodes, fibers, and next-generation industrial fiber lasers at power levels of 500 W - 8 kW. We show back-reflection studies with up to 1 kW of back-reflected power, power-stability measurements in cw and modulated operation exhibiting sub-1% stability over a 5 - 100% power range, and high-speed modulation (100 kHz) and waveform generation with a bandwidth 20x higher than standard fiber lasers. We show results from representative applications, including cutting and welding of highly reflective metals (Cu and Al) for production of Li-ion battery modules and processing of carbon fiber reinforced polymers.

Optimization of 248nm bottom anti-reflective coatings with thin film and high etch rate on real device

NASA Astrophysics Data System (ADS)

Kim, MyoungSoo; Kim, HakJoon; Shim, KewChan; Jeon, JeHa; Gil, MyungGoon; Song, YongWook; Enomoto, Tomoyuki; Sakaguchi, Takahiro; Nakajima, Yasuyuki

2005-05-01

A frequent problem encountered by photoresists during the manufacturing of semiconductor device is that activating radiation is reflected back into the photoresist by the substrate. So, it is necessary that the light reflection is reduced from the substrate. One approach to reduce the light reflection is the use of bottom anti-reflective coating (BARC) applied to the substrate beneath the photoresist layer. The BARC technology has been utilized for a few years to minimize the reflectivity. As the chip size is reduced to sub 100nm, the photoresist thickness has to decrease with the aspect ratio being less than 3.0. Therefore, new Organic BARC is strongly required which has the minimum reflectivity with thinner BARC thickness and higher etch selectivity toward resists. Hynix Semiconductor Inc., Nissan Chemical Industries, Ltd., and Brewer Science, Inc. have developed the advanced Organic BARC for achieving the above purpose. As a result, the suitable high performance 248nm Organic BARCs, NCA series, were achieved. Using CF4 gas as etchant, the plasma etch rate of NCA series is about 1.4 times higher than that of conventional 248nm resists. NCA series can be minimizing the substrate reflectivity at below 45nm BARC thickness. NCA series show the excellent litho performance and coating property on real device.

Near zero reflection by nanostructured anti-reflection coating design for Si substrates

NASA Astrophysics Data System (ADS)

Al-Fandi, Mohamed; Makableh, Yahia F.; Khasawneh, Mohammad; Rabady, Rabi

2018-05-01

The nanostructure design of near zero reflection coating for Si substrates by using ZnO Nanoneedles (ZnONN) is performed and optimized for the visible spectral range. The design investigates the ZnONN tip to body ratio effect on the anti-reflection coating properties. Different tip to body ratios are used on Si substrates. Around zero reflection is achieved by the Nanoneedles structure design presented in this work, leading to minimal reflection losses from the Si surface. The current design evolves a solution to optical losses and surface contamination effects associated with Si solar cells.

Condenser optic with sacrificial reflective surface

DOEpatents

Tichenor, Daniel A.; Kubiak, Glenn D.; Lee, Sang Hun

2006-07-25

Employing collector optics that have a sacrificial reflective surface can significantly prolong the useful life of the collector optics and the overall performance of the condenser in which the collector optics are incorporated. The collector optics are normally subject to erosion by debris from laser plasma source of radiation. The presence of an upper sacrificial reflective surface over the underlying reflective surface effectively increases the life of the optics while relaxing the constraints on the radiation source. Spatial and temporally varying reflectivity that results from the use of the sacrificial reflective surface can be accommodated by proper condenser design.

Condenser optic with sacrificial reflective surface

DOEpatents

Tichenor, Daniel A [Castro Valley, CA; Kubiak, Glenn D [Livermore, CA; Lee, Sung Hun [Sunnyvale, CA

2007-07-03

Employing collector optics that has a sacrificial reflective surface can significantly prolong the useful life of the collector optics and the overall performance of the condenser in which the collector optics are incorporated. The collector optics is normally subject to erosion by debris from laser plasma source of radiation. The presence of an upper sacrificial reflective surface over the underlying reflective surface effectively increases the life of the optics while relaxing the constraints on the radiation source. Spatial and temporally varying reflectivity that results from the use of the sacrificial reflective surface can be accommodated by proper condenser design.

Effect of students' learning styles on classroom performance in problem-based learning.

PubMed

Alghasham, Abdullah A

2012-01-01

Since problem-based learning (PBL) sessions require a combination of active discussion, group interaction, and inductive and reflective thinking, students with different learning styles can be expected to perform differently in the PBL sessions. Using "Learning Style Inventory Questionnaire," students were divided into separate active and reflective learner groups. Tutors were asked to observe and assess the students' behavioral performance during the PBL sessions for a period of 5 weeks. A questionnaire of 24 items was developed to assess students' behavioral performance in PBL sessions. Active students tended to use multiple activities to obtain the needed information were more adjusted to the group norms and regulation and more skillful in using reasoning and problem-solving skills and in participation in discussion. On the other hand, reflective students used independent study more, listened actively and carefully to others and used previously acquired information in the discussion more frequently. Formative assessment quizzes did not indicate better performance of either group. There were no significant gender differences in PBL behavioral performance or quizzes' scores. Active and reflective learners differ in PBL class behavioral performance but not in the formative assessment. We recommend that students should be informed about their learning style and that they should learn strategies to compensate for any lacks in PBL sessions through self-study. Also, educational planners should ensure an adequate mix of students with different learning styles in the PBL groups to achieve PBL desired objectives.

Performance testing of an off-plane reflection grating and silicon pore optic spectrograph at PANTER

NASA Astrophysics Data System (ADS)

Marlowe, Hannah; McEntaffer, Randall L.; Allured, Ryan; DeRoo, Casey T.; Donovan, Benjamin D.; Miles, Drew M.; Tutt, James H.; Burwitz, Vadim; Menz, Benedikt; Hartner, Gisela D.; Smith, Randall K.; Cheimets, Peter; Hertz, Edward; Bookbinder, Jay A.; Günther, Ramses; Yanson, Alex; Vacanti, Giuseppe; Ackermann, Marcelo

2015-10-01

An x-ray spectrograph consisting of aligned, radially ruled off-plane reflection gratings and silicon pore optics (SPO) was tested at the Max Planck Institute for Extraterrestrial Physics PANTER x-ray test facility. SPO is a test module for the proposed Arcus mission, which will also feature aligned off-plane reflection gratings. This test is the first time two off-plane gratings were actively aligned to each other and with an SPO to produce an overlapped spectrum. We report the performance of the complete spectrograph utilizing the aligned gratings module and plans for future development.

Channel Model Optimization with Reflection Residual Component for Indoor MIMO-VLC System

NASA Astrophysics Data System (ADS)

Chen, Yong; Li, Tengfei; Liu, Huanlin; Li, Yichao

2017-12-01

A fast channel modeling method is studied to solve the problem of reflection channel gain for multiple input multiple output-visible light communications (MIMO-VLC) in the paper. For reducing the computational complexity when associating with the reflection times, no more than 3 reflections are taken into consideration in VLC. We think that higher order reflection link consists of corresponding many times line of sight link and firstly present reflection residual component to characterize higher reflection (more than 2 reflections). We perform computer simulation results for point-to-point channel impulse response, receiving optical power and receiving signal to noise ratio. Based on theoretical analysis and simulation results, the proposed method can effectively reduce the computational complexity of higher order reflection in channel modeling.

Performance of three reflectance calibration methods for airborne hyperspectral spectrometer data.

PubMed

Miura, Tomoaki; Huete, Alfredo R

2009-01-01

In this study, the performances and accuracies of three methods for converting airborne hyperspectral spectrometer data to reflectance factors were characterized and compared. The "reflectance mode (RM)" method, which calibrates a spectrometer against a white reference panel prior to mounting on an aircraft, resulted in spectral reflectance retrievals that were biased and distorted. The magnitudes of these bias errors and distortions varied significantly, depending on time of day and length of the flight campaign. The "linear-interpolation (LI)" method, which converts airborne spectrometer data by taking a ratio of linearly-interpolated reference values from the preflight and post-flight reference panel readings, resulted in precise, but inaccurate reflectance retrievals. These reflectance spectra were not distorted, but were subject to bias errors of varying magnitudes dependent on the flight duration length. The "continuous panel (CP)" method uses a multi-band radiometer to obtain continuous measurements over a reference panel throughout the flight campaign, in order to adjust the magnitudes of the linear-interpolated reference values from the preflight and post-flight reference panel readings. Airborne hyperspectral reflectance retrievals obtained using this method were found to be the most accurate and reliable reflectance calibration method. The performances of the CP method in retrieving accurate reflectance factors were consistent throughout time of day and for various flight durations. Based on the dataset analyzed in this study, the uncertainty of the CP method has been estimated to be 0.0025 ± 0.0005 reflectance units for the wavelength regions not affected by atmospheric absorptions. The RM method can produce reasonable results only for a very short-term flight (e.g., < 15 minutes) conducted around a local solar noon. The flight duration should be kept shorter than 30 minutes for the LI method to produce results with reasonable accuracies. An important advantage of the CP method is that the method can be used for long-duration flight campaigns (e.g., 1-2 hours). Although this study focused on reflectance calibration of airborne spectrometer data, the methods evaluated in this study and the results obtained are directly applicable to ground spectrometer measurements.

Fairness and Using Reflective Journals in Assessment

ERIC Educational Resources Information Center

Clarkeburn, Henriikka; Kettula, Kirsi

2012-01-01

This study looks at the fairness of assessing learning journals both as the fairness in creating a valid and robust marking process as well as how different student groups may have unfair disadvantages in performing well in reflective assessment tasks. The fairness of a marking process is discussed through reflecting on the practical process and…

Spectral reflectance and radiance characteristics of water pollutants

NASA Technical Reports Server (NTRS)

Wezernak, C. T.; Turner, R. E.; Lyzenga, D. R.

1976-01-01

Spectral reflectance characteristics of water pollutants and water bodies were compiled using the existing literature. Radiance calculations were performed at satellite altitude for selected illumination angles and atmospheric conditions. The work described in this report was limited to the reflective portion of the spectrum between 0.40 micrometer to 1.0 micrometer.

Formative versus Reflective Measurement of Executive Function Tasks: Response to Commentaries and Another Perspective

ERIC Educational Resources Information Center

Willoughby, Michael T.

2014-01-01

The focus article (Willoughby et al., 2014) (1) introduced the distinction between formative and reflective measurement and (2) proposed that performance-based executive function tasks may be better conceptualized from the perspective of formative rather than reflective measurement. This proposal stands in sharp contrast to conventional…

Agents of Change in Promoting Reflective Abstraction: A Quasi-Experimental, Study on Limits in College Calculus

ERIC Educational Resources Information Center

Cappetta, Robert W.; Zollman, Alan

2013-01-01

We measured student performance on the concept of limit by promoting reflection through four agents of change: instructor, peer, curriculum and individual. It is based on Piaget's four constructs of reflective abstraction: interiorization, coordination, encapsulation, and generalization, and includes the notion of reversal, as refined into a…

Learning by Thinking during Play: The Power of Reflection to Aid Performance

ERIC Educational Resources Information Center

Salmon, Angela K.

2016-01-01

Coupled with reflection, play leads to the development of thinking dispositions and promotes deep learning and understanding. The twenty-first century world demands that children learn how to learn by becoming reflective, self-regulating inquirers capable of metacognition (thinking about thinking). This manuscript aims to analyse how young minds…

The Performance in Context Model: A 21st Century Tertiary Dance Teaching Pedagogy

ERIC Educational Resources Information Center

Stevens, Kym; Huddy, Avril

2016-01-01

Despite tertiary institutions acknowledging that reflective practice is an essential component of undergraduate dance teacher training, there is often a disparity between the tertiary students' reflective skills and the more sophisticated reflective ability needed to navigate the twenty-first-century workforce. This paper charts the evolution of a…

Evaluation of Student Reflection as a Route to Improve Oral Communication

ERIC Educational Resources Information Center

Mineart, Kenneth P.; Cooper, Matthew E.

2016-01-01

This study describes the use of guided self-reflection and peer feedback activities to improve student oral communication in a large ChE class (n ~ 100) setting. Student performance tracked throughout an experimental semester indicated both reflection activities accelerated improvement in oral communication over control; student perception of the…

Reduction of cross-polarized reflection to enhance dual-band absorption

NASA Astrophysics Data System (ADS)

Kundu, Debidas; Mohan, Akhilesh; Chakrabarty, Ajay

2016-11-01

In this paper, cross-polarized reflection from a periodic array of metal-dielectric-metal resonator units is reduced to improve its absorbing performance. Through this simple and typical example, it is shown that some reported absorbers are actually poor absorbers but efficient polarization converters, when the cross-polarized reflection is considered. Using a frequency selective surface, sandwiched between the top layer and the ground plane, the cross-polarized reflection is reduced by 7.2 dB at 5.672 GHz and 8.5 dB at 9.56 GHz, while negligibly affecting the co-polarized reflection reduction performance. The polarization conversion ratio is reduced from 90. 74% to 34.12% and 98.51% to 27.2% and total absorption is improved up to 80% from 26% and 21% around the two resonant frequencies. The reflection characteristics of the proposed absorber are quantitatively analyzed using interference theory, where the near field coupling of the resonant geometries and ground is taken into account. Measurement results show good agreement with both the numerically simulated and theoretical results.

A Three-Year Reflective Writing Program as Part of Introductory Pharmacy Practice Experiences

PubMed Central

Vaughn, Jessica; Kerr, Kevin; Zielenski, Christopher; Toppel, Brianna; Johnson, Lauren; McCauley, Patrina; Turner, Christopher J.

2013-01-01

Objectives. To implement and evaluate a 3-year reflective writing program incorporated into introductory pharmacy practice experiences (IPPEs) in the first- through third-year of a doctor of pharmacy (PharmD) program. Design. Reflective writing was integrated into 6 IPPE courses to develop students’ lifelong learning skills. In their writing, students were required to self-assess their performance in patient care activities, identify and describe how they would incorporate learning opportunities, and then evaluate their progress. Practitioners, faculty members, and fourth-year PharmD students served as writing preceptors. Assessment. The success of the writing program was assessed by reviewing class performance and surveying writing preceptor’s opinions regarding the student’s achievement of program objectives. Class pass rates averaged greater than 99% over the 8 years of the program and the large majority of the writing preceptors reported that student learning objectives were met. A support pool of 99 writing preceptors was created. Conclusions. A 3-year reflective writing program improved pharmacy students’ reflection and reflective writing skills. PMID:23788811

Performance impact of novel polymeric dyes in photoresist applications

NASA Astrophysics Data System (ADS)

Lu, Ping-Hung; Mehtsun, Salem; Sagan, John P.; Shan, Jianhui; Gonzalez, Eleazar; Ding, Shuji; Khanna, Dinesh N.

1999-06-01

Dye compounds are commonly used in photoresists as a low cost and effective way to control swing and/or standing wave effect caused by thin film interference as well as reflective notching by reflective light from highly reflective substrate and topography. Convention dyes are typically a monomeric compound with high absorptivity at the wavelength of exposure light and compatible with the resist system selected. Because of the monomeric nature, conventional dyes are relatively low in molecular weight hence their thermal stability and sublimination propensity has always been an issue of concern. We recently synthesize several highly thermal stable diazotized polymeric dyes. Their thermal properties as well as compatibility with resist system were investigated. The impact of polymeric dyes on the resists lithographic performance, swing reduction and reflective notching control are discussed.

Image quality degradation by light-scattering processes in high-performance display devices for medical imaging

NASA Astrophysics Data System (ADS)

Badano, Aldo

1999-11-01

This thesis addresses the characterization of light scattering processes that degrade image quality in high performance electronic display devices for digital radiography. Using novel experimental and computational tools, we study the lateral diffusion of light in emissive display devices that causes extensive veiling glare and significant reduction of the physical contrast. In addition, we examine the deleterious effects of ambient light reflections that affect the contrast of low luminance regions, and superimpose unwanted structured signal. The analysis begins by introducing the performance limitations of the human visual system to define high fidelity requirements. It is noted that current devices severely suffer from image quality degradation due to optical transport processes. To model the veiling glare and reflectance characteristics of display devices, we introduce a Monte Carlo light transport simulation code, DETECT-II, that tracks individual photons through multiple scattering events. The simulation accounts for the photon polarization state at each scattering event, and provides descriptions for rough surfaces and thin film coatings. A new experimental method to measure veiling glare is described next, based on a conic collimated probe that minimizes contamination from bright areas. The measured veiling glare ratio is taken to be the luminance in the surrounding bright field divided by the luminance in the dark circle. We show that veiling glare ratios in the order of a few hundreds can be measured with an uncertainty of a few percent. The veiling glare response function is obtained by measuring the small spot contrast ratio of test patterns having varying dark spot radius. Using DETECT-II, we then estimate the ring response functions for a high performance medical imaging monitor of current design, and compare the predictions of the model with the experimentally measured response function. The data presented in this thesis demonstrate that although absorption in the faceplate of high performance monochrome cathode-ray tube monitors have reduced glare, a black matrix design is needed for high fidelity applications. For a high performance medical imaging monitor with anti-reflective coating, the glare ratio for a 1 cm diameter dark spot was measured to be 240. Finally, we introduce experimental techniques for measurements of specular and diffuse display reflectance, and we compare measured reflection coefficients with Monte Carlo estimates. A specular reflection coefficient of 0.0012, and a diffuse coefficient of 0.005 nits/lux are required to minimize degradation from ambient light in rooms with 100 lux illumination. In spite of having comparable reflection coefficients, the low maximum luminance of current devices worsens the effect of ambient light reflections when compared to radiographic film. Flat panel technologies with optimized designs can perform even better than film due to a thin faceplate, increased light absorption, and high brightness.

Flexible thermal protection materials for entry systems

NASA Astrophysics Data System (ADS)

Kourtides, Demetrius A.

1993-02-01

Current programs addressed in aeroassist flight experiment are: (1) evaluation of thermal performance of advanced rigid and flexible insulations and reflective coating; (2) investigation of lighter than baseline materials; (3) investigation of rigid insulations which perform well; (4) study of flexible insulations which require ceramic coating; and (5) study of reflective coating effective at greater than 15 percent. In National Aerospace Plane (NASP), the programs addressed are: (1) high and low temperature insulations; and (2) attachment/standoff methodology critical which affects thermal performance.

Flexible thermal protection materials for entry systems

NASA Technical Reports Server (NTRS)

Kourtides, Demetrius A.

1993-01-01

Current programs addressed in aeroassist flight experiment are: (1) evaluation of thermal performance of advanced rigid and flexible insulations and reflective coating; (2) investigation of lighter than baseline materials; (3) investigation of rigid insulations which perform well; (4) study of flexible insulations which require ceramic coating; and (5) study of reflective coating effective at greater than 15 percent. In National Aerospace Plane (NASP), the programs addressed are: (1) high and low temperature insulations; and (2) attachment/standoff methodology critical which affects thermal performance.

Developments of new force reflecting control schemes and an application to a teleoperation training simulator

NASA Technical Reports Server (NTRS)

Kim, Won S.

1992-01-01

Two schemes of force reflecting control, position-error based force reflection and low-pass-filtered force reflection, both combined with shared compliance control, were developed for dissimilar master-slave arms. These schemes enabled high force reflection gains, which were not possible with a conventional scheme when the slave arm was much stiffer than the master arm. The experimental results with a peg-in-hole task indicated that the newly force reflecting control schemes combined with compliance control resulted in best task performances. As a related application, a simulated force reflection/shared compliance control teleoperation trainer was developed that provided the operator with the feel of kinesthetic force virtual reality.

Specific Features of Destabilization of the Wave Profile During Reflection of an Intense Acoustic Beam from a Soft Boundary

NASA Astrophysics Data System (ADS)

Deryabin, M. S.; Kasyanov, D. A.; Kurin, V. V.; Garasyov, M. A.

2016-05-01

We show that a significant energy redistribution occurs in the spectrum of reflected nonlinear waves, when an intense acoustic beam is reflected from an acoustically soft boundary, which manifests itself at short wave distances from a reflecting boundary. This effect leads to the appearance of extrema in the distributions of the amplitude and intensity of the field of the reflected acoustic beam near the reflecting boundary. The results of physical experiments are confirmed by numerical modeling of the process of transformation of nonlinear waves reflected from an acoustically soft boundary. Numerical modeling was performed by means of the Khokhlov—Zabolotskaya—Kuznetsov (KZK) equation.

Engineering design of sub-micron topographies for simultaneously adherent and reflective metal-polymer interfaces

NASA Technical Reports Server (NTRS)

Brown, Christopher A.

1993-01-01

The approach of the project is to base the design of multi-function, reflective topographies on the theory that topographically dependent phenomena react with surfaces and interfaces at certain scales. The first phase of the project emphasizes the development of methods for understanding the sizes of topographic features which influence reflectivity. Subsequent phases, if necessary, will address the scales of interaction for adhesion and manufacturing processes. A simulation of the interaction of electromagnetic radiation, or light, with a reflective surface is performed using specialized software. Reflectivity of the surface as a function of scale is evaluated and the results from the simulation are compared with reflectivity measurements made on multi-function, reflective surfaces.

Effect of aperiodicity on the broadband reflection of silicon nanorod structures for photovoltaics.

PubMed

Lin, Chenxi; Huang, Ningfeng; Povinelli, Michelle L

2012-01-02

We carry out a systematic numerical study of the effects of aperiodicity on silicon nanorod anti-reflection structures. We use the scattering matrix method to calculate the average reflection loss over the solar spectrum for periodic and aperiodic arrangements of nanorods. We find that aperiodicity can either improve or deteriorate the anti-reflection performance, depending on the nanorod diameter. We use a guided random-walk algorithm to design optimal aperiodic structures that exhibit lower reflection loss than both optimal periodic and random aperiodic structures.

FUV Reflectance of Recently Prepared Al Protected with AlF3: COR Program Technology Development

NASA Technical Reports Server (NTRS)

Quijada, Manuel

2016-01-01

Astronomical observations in the Far Ultraviolet (FUV) spectral region are some of the more challenging due to the very distant and faint objects that are typically searched for in cosmic origin studies such as origin of large scale structure, the formation, evolution, and age of galaxies and the origin of stellar and planetary systems. These challenges are driving the need to improve the performance of optical coatings over a wide spectral range that would increase reflectance in mirrors and reduced absorption in dielectric filters used in optical telescope for FUV observations. This paper will present recent advances in reflectance performance for Al+AlF3 mirrors optimized for Lyman-alpha wavelength by performing the deposition of the AlF3 overcoat at elevated substrate temperatures.

On-Orbit Noise Characterization for MODIS Reflective Solar Bands

NASA Technical Reports Server (NTRS)

Xiong, X.; Xie, X.; Angal, A.

2008-01-01

Since launch, the Moderate Resolution Imaging Spectroradiometer (MODIS) has operated successfully on-board the NASA Earth Observing System (EOS) Terra and EOS Aqua spacecraft. MODIS is a passive cross-track scanning radiometer that makes observations in 36 spectral bands with spectral wavelengths from visible (VIS) to long-wave infrared. MODIS bands 1-19 and 26 are the reflective solar bands (RSB) with wavelengths from 0.41 to 2.2 micrometers. They are calibrated on-orbit using an on-board solar diffuser (SD) and a SD stability monitor (SDSM) system. For MODIS RSB, the level 1B calibration algorithm produces top of the atmosphere reflectance factors and radiances for every pixel of the Earth view. The sensor radiometric calibration accuracy, specified at each spectral band's typical scene radiance, is 2% for the RSB reflectance factors and 5% for the RSB radiances. Also specified at the typical scene radiance is the detector signal-to-noise ratio (SNR), a key sensor performance parameter that directly impacts its radiometric calibration accuracy and stability, as well as the image quality. This paper describes an on-orbit SNR characterization approach developed to evaluate and track MODIS RSB detector performance. In order to perform on-orbit SNR characterization, MODIS RSB detector responses to the solar illumination reflected from the SD panel must be corrected for factors due to variations of the solar angles and the SD bi-directional reflectance factor. This approach enables RSB SNR characterization to be performed at different response levels for each detector. On-orbit results show that both Terra and Aqua MODIS RSB detectors have performed well since launch. Except for a few noisy or inoperable detectors which were identified pre-launch, most RSB detectors continue to meet the SNR design requirements and are able to maintain satisfactory short-term stability. A comparison of on-orbit noise characterization results with results derived from pre-launch calibration and characterization are also provided.

GEO-LEO reflectance band inter-comparison with BRDF and atmospheric scattering corrections

NASA Astrophysics Data System (ADS)

Chang, Tiejun; Xiong, Xiaoxiong Jack; Keller, Graziela; Wu, Xiangqian

2017-09-01

The inter-comparison of the reflective solar bands between the instruments onboard a geostationary orbit satellite and onboard a low Earth orbit satellite is very helpful to assess their calibration consistency. GOES-R was launched on November 19, 2016 and Himawari 8 was launched October 7, 2014. Unlike the previous GOES instruments, the Advanced Baseline Imager on GOES-16 (GOES-R became GOES-16 after November 29 when it reached orbit) and the Advanced Himawari Imager (AHI) on Himawari 8 have onboard calibrators for the reflective solar bands. The assessment of calibration is important for their product quality enhancement. MODIS and VIIRS, with their stringent calibration requirements and excellent on-orbit calibration performance, provide good references. The simultaneous nadir overpass (SNO) and ray-matching are widely used inter-comparison methods for reflective solar bands. In this work, the inter-comparisons are performed over a pseudo-invariant target. The use of stable and uniform calibration sites provides comparison with appropriate reflectance level, accurate adjustment for band spectral coverage difference, reduction of impact from pixel mismatching, and consistency of BRDF and atmospheric correction. The site in this work is a desert site in Australia (latitude -29.0 South; longitude 139.8 East). Due to the difference in solar and view angles, two corrections are applied to have comparable measurements. The first is the atmospheric scattering correction. The satellite sensor measurements are top of atmosphere reflectance. The scattering, especially Rayleigh scattering, should be removed allowing the ground reflectance to be derived. Secondly, the angle differences magnify the BRDF effect. The ground reflectance should be corrected to have comparable measurements. The atmospheric correction is performed using a vector version of the Second Simulation of a Satellite Signal in the Solar Spectrum modeling and BRDF correction is performed using a semi-empirical model. AHI band 1 (0.47μm) shows good matching with VIIRS band M3 with difference of 0.15%. AHI band 5 (1.69μm) shows largest difference in comparison with VIIRS M10.

Effective light coupling in reflective fiber optic distance sensors using a double-clad fiber

NASA Astrophysics Data System (ADS)

Werzinger, Stefan; Härteis, Lisa; Köhler, Aaron; Engelbrecht, Rainer; Schmauss, Bernhard

2017-04-01

Many fiber optic distance sensors use a reflective configuration, where a light beam is launched from an optical fiber, reflected from a target and coupled back into the fiber. While singlemode fibers (SMF) provide low-loss, high-performance components and a well-defined output beam, the coupling of the reflected light into the SMF is very sensitive to mechanical misalignments and scattering at the reflecting target. In this paper we use a double-clad fiber (DCF) and a DCF coupler to obtain an enhanced multimodal coupling of reflected light into the fiber. Increased power levels and robustness are achieved compared to a pure SMF configuration.

[Pedagogical reflective practice of nursing undergraduates: the portfolio as an instrument].

PubMed

Vaz, Débora Rodrigues; Prado, Cláudia

2014-12-01

Analyzing the narratives related to the pedagogical practice experienced during the Supervised Curricular Internship reported in the portfolios of Nursing undergraduate students, regarding the levels of reflection. This is a documentary descriptive exploratory study that examined two of the activities proposed for the portfolio preparation. Among the 28 analyzed portfolios, all showed the three levels of reflection (technical, critical and metacritical). The students had the opportunity to experience the pedagogical practice and presented reflections at metacritical level, reflecting on their performance, the construction of their teaching identity, and about the importance of reflecting on the practice with the objective of transforming it and transforming themselves.

Early Evaluation of the VIIRS Calibration, Cloud Mask and Surface Reflectance Earth Data Records

NASA Technical Reports Server (NTRS)

Vermote, Eric; Justice, Chris; Csiszar, Ivan

2014-01-01

Surface reflectance is one of the key products fromVIIRS and as withMODIS, is used in developing several higherorder land products. The VIIRS Surface Reflectance (SR) Intermediate Product (IP) is based on the heritageMODIS Collection 5 product (Vermote, El Saleous, & Justice, 2002). The quality and character of surface reflectance depend on the accuracy of the VIIRS Cloud Mask (VCM), the aerosol algorithms and the adequate calibration of the sensor. The focus of this paper is the early evaluation of the VIIRS SR product in the context of the maturity of the operational processing system, the Interface Data Processing System (IDPS). After a brief introduction, the paper presents the calibration performance and the role of the surface reflectance in calibration monitoring. The analysis of the performance of the cloud mask with a focus on vegetation monitoring (no snow conditions) shows typical problems over bright surfaces and high elevation sites. Also discussed is the performance of the aerosol input used in the atmospheric correction and in particular the artifacts generated by the use of the Navy Aerosol Analysis and Prediction System. Early quantitative results of the performance of the SR product over the AERONET sites showthatwith the fewadjustments recommended, the accuracy iswithin the threshold specifications. The analysis of the adequacy of the SR product (Land PEATE adjusted version) in applications of societal benefits is then presented. We conclude with a set of recommendations to ensure consistency and continuity of the JPSS mission with the MODIS Land Climate Data Record.

Bragg reflection band width and optical rotatory dispersion of cubic blue-phase liquid crystals

NASA Astrophysics Data System (ADS)

Yoshida, Hiroyuki; Anucha, Konkanok; Ogawa, Yasuhiro; Kawata, Yuto; Ozaki, Masanori; Fukuda, Jun-ichi; Kikuchi, Hirotsugu

2016-10-01

The Bragg reflection band width and optical rotatory dispersion of liquid crystalline cholesteric blue phases (BPs) I and II are compared by numerical simulations. Attention is paid to the wavelength regions for which the reflection bands with lowest photon energies appear, i.e., the [110 ] direction for BP I and the [100 ] direction for BP II. Finite difference time domain and 4 ×4 matrix calculations performed on the theoretical director tensor distribution of BPs with the same material parameters show that BP II, which has simple cubic symmetry, has a wider photonic band gap than BP I, which has body centered cubic symmetry, possibly due to the fact that the density of the double-twist cylinders in BP II are twice that in BP I. The theoretical results on the Bragg reflection band width are supported by reflectance measurements performed on BPs I and II for light incident along the [110 ] and [100 ] directions, respectively.

Infrared Radiative Properties of Yttria-Stabilized Zirconia Thermal Barrier Coatings

NASA Technical Reports Server (NTRS)

Eldridge, Jeff I.; Spuckler, Charles M.; Street, Ken W.; Markham, Jim R.; Gray, Hugh R. (Technical Monitor)

2002-01-01

The infrared (IR) transmittance and reflectance of translucent thermal barrier coatings (TBCs) have important implications for both the performance of these coatings as radiation barriers and emitters as well as affecting measurements of TBC thermal conductivity, especially as TBCs are being pushed to higher temperatures. In this paper, the infrared spectral directional-hemispherical transmittance and reflectance of plasma-sprayed 8wt% yttria-stabilized zirconia (8YSZ) TBCs are reported. These measurements are compared to those for single crystal YSZ specimens to show the effects of the plasma-sprayed coating microstructure. It is shown that the coatings exhibit negligible absorption at wavelengths up to about 5 micrometers, and that internal scattering rather than surface reflections dominates the hemispherical reflectance. The translucent nature of the 8YSZ TBCs results in the absorptance/emittance and reflectance of TBC-coated substrates depending on the TBC thickness, microstructure, as well as the radiative properties of the underlying substrate. The effects of these properties on TBC measurements and performance are discussed.

Structured Reflection Breaks Embedded in an Online Course--Effects on Learning Experience, Time on Task and Performance

ERIC Educational Resources Information Center

Verpoorten, Dominique; Westera, Wim

2016-01-01

The purpose of this article is to gain an insight into the effects of practicing short, frequent, and structured reflection breaks interspersed with the learning material in a computer-based course. To that end, the study sets up a standardized control trial with two groups of secondary school pupils. The study shows that while performance is not…

Effects of Matching Teaching Strategy to Thinking Style on Learner's Quality of Reflection in an Online Learning Environment

ERIC Educational Resources Information Center

Chen, Nian-Shing; Kinshuk; Wei, Chun-Wang; Liu, Chia-Chi

2011-01-01

Reflection plays an important role in improving learning performance. This study, therefore, attempted to explore whether learners' reflection levels can be improved if teaching strategies are adapted to fit with learners' thinking styles in an online learning environment. Three teaching strategies, namely constructive, guiding, and inductive,…

Variations in Form and Skill: Supporting Multiple Orientations to Reflective Thinking in Leadership Preparation

ERIC Educational Resources Information Center

Carver, Cynthia L; Klein, C. Suzanne

2016-01-01

Drawing on data collected as part of a qualitative action research study, our analysis examines the reflective thinking skill of candidates as they begin a two-year principal preparation program. As leadership educators, we noticed that our highest performing students were also the most skilled at thinking reflectively. Using candidates' writing…

Critical Reflection of an Iranian EFL Classroom: Effective Ploys in Narrative Paragraph Writing Development

ERIC Educational Resources Information Center

Jafari, Fatemeh Mohammad; Ameri, Alireza

2015-01-01

This article describes a qualitative study that investigated critical reflection in the hope that effective learning is objectified. It is the fruit of rumination on how critical reflection approach would affect learners' performance in narrative writing. The idea for this paper arose when the researchers consistently utilized ploys effective for…

The Impotence of Being Important – Reflections on Leadership

PubMed Central

Couper, Ian Douglas

2007-01-01

An observed doctor-patient encounter, in which impotence and importance were confused, led me to a reflection on leadership. A sense of importance can be destructive in leadership, leading to failure to perform, or impotence. Understanding the dangers of self-importance, I am challenged to ensure that I regularly reflect on my leadership style. PMID:17548855

Influence of resonant transducer variations on long range guided wave monitoring of rail track

NASA Astrophysics Data System (ADS)

Loveday, Philip W.; Long, Craig S.

2016-02-01

The ability of certain guided wave modes to propagate long distances in continuously welded rail track is exploited in permanently installed monitoring systems. Previous work demonstrated that reflections from thermite welds could be measured at distances of the order of 1 km from a transducer array. The availability of numerous thermite welds is useful during the development of a monitoring system as real defects are not available. Measurements of reflections from welds were performed over an eleven month period with two permanently installed transducers. Phased array processing was performed and the true location of a weld is indicated by a strong reflection but there is generally also a smaller, spurious replica reflection, at the same distance but in the incorrect direction. In addition, the relative reflection from different welds appears to change over time. The influence of differences between the two resonant transducers was investigated using a model. It was found that estimating the attenuation in either direction and scaling the reflections in either direction decreased the variability in the reflection measurements. Transducer interaction effects, where the transducer closer to the weld records a greater reflection than the second transducer were observed and can be used to determine the direction of a weld. This feature was used to demonstrate a simple alternative to phased array processing that can be used with resonant transducers.

A validation study of the psychometric properties of the Groningen Reflection Ability Scale.

PubMed

Andersen, Nina Bjerre; O'Neill, Lotte; Gormsen, Lise Kirstine; Hvidberg, Line; Morcke, Anne Mette

2014-10-10

Reflection, the ability to examine critically one's own learning and functioning, is considered important for 'the good doctor'. The Groningen Reflection Ability Scale (GRAS) is an instrument measuring student reflection, which has not yet been validated beyond the original Dutch study. The aim of this study was to adapt GRAS for use in a Danish setting and to investigate the psychometric properties of GRAS-DK. We performed a cross-cultural adaptation of GRAS from Dutch to Danish. Next, we collected primary data online, performed a retest, analysed data descriptively, estimated measurement error, performed an exploratory and a confirmatory factor analysis to test the proposed three-factor structure. 361 (69%) of 523 invited students completed GRAS-DK. Their mean score was 88 (SD = 11.42; scale maximum 115). Scores were approximately normally distributed. Measurement error and test-retest score differences were acceptable, apart from a few extreme outliers. However, the confirmatory factor analysis did not replicate the original three-factor model and neither could a one-dimensional structure be confirmed. GRAS is already in use, however we advise that use of GRAS-DK for effect measurements and group comparison awaits further review and validation studies. Our negative finding might be explained by a weak conceptualisation of personal reflection.

Performance evaluation of a six-axis generalized force-reflecting teleoperator

NASA Technical Reports Server (NTRS)

Hannaford, B.; Wood, L.; Guggisberg, B.; Mcaffee, D.; Zak, H.

1989-01-01

Work in real-time distributed computation and control has culminated in a prototype force-reflecting telemanipulation system having a dissimilar master (cable-driven, force-reflecting hand controller) and a slave (PUMA 560 robot with custom controller), an extremely high sampling rate (1000 Hz), and a low loop computation delay (5 msec). In a series of experiments with this system and five trained test operators covering over 100 hours of teleoperation, performance was measured in a series of generic and application-driven tasks with and without force feedback, and with control shared between teleoperation and local sensor referenced control. Measurements defining task performance included 100-Hz recording of six-axis force/torque information from the slave manipulator wrist, task completion time, and visual observation of predefined task errors. The task consisted of high precision peg-in-hole insertion, electrical connectors, velcro attach-de-attach, and a twist-lock multi-pin connector. Each task was repeated three times under several operating conditions: normal bilateral telemanipulation, forward position control without force feedback, and shared control. In shared control, orientation was locally servo controlled to comply with applied torques, while translation was under operator control. All performance measures improved as capability was added along a spectrum of capabilities ranging from pure position control through force-reflecting teleoperation and shared control. Performance was optimal for the bare-handed operator.

Performance testing of a novel off-plane reflection grating and silicon pore optic spectrograph at PANTER

NASA Astrophysics Data System (ADS)

Marlowe, Hannah; McEntaffer, Randall L.; Allured, Ryan; DeRoo, Casey; Miles, Drew M.; Donovan, Benjamin D.; Tutt, James H.; Burwitz, Vadim; Menz, Benedikt; Hartner, Gisela D.; Smith, Randall K.; Günther, Ramses; Yanson, Alex; Vacanti, Giuseppe; Ackermann, Marcelo

2015-05-01

An X-ray spectrograph consisting of aligned, radially ruled off-plane reflection gratings and silicon pore optics (SPO) was tested at the Max Planck Institute for extraterrestrial Physics PANTER X-ray test facility. The SPO is a test module for the proposed Arcus mission, which will also feature aligned off-plane reflection gratings. This test is the first time two off-plane gratings were actively aligned to each other and with a SPO to produce an overlapped spectrum. We report the performance of the complete spectrograph utilizing the aligned gratings module and plans for future development.

Effects of a work-based critical reflection program for novice nurses.

PubMed

Kim, Yeon Hee; Min, Ja; Kim, Soon Hee; Shin, Sujin

2018-02-27

Critical reflection is effective in improving students' communication abilities and confidence. The aim of this study was to evaluate the effectiveness of a work-based critical reflection program to enhance novice nurses' clinical critical-thinking abilities, communication competency, and job performance. The present study used a quasi-experimental design. From October 2014 to August 2015, we collected data from 44 novice nurses working in an advanced general hospital in S city in Korea. Nurses in the experimental group participated in a critical reflection program for six months. Outcome variables were clinical critical-thinking skills, communication abilities, and job performance. A non-parametric Mann-Whitney U-test and a Wilcoxon rank sum test were selected to evaluate differences in mean ranks and to assess the null hypothesis that the medians were equal across the groups. The results showed that the clinical critical-thinking skills of those in the experimental group improved significantly (p = 0.003). The differences in mean ranks of communication ability between two groups was significantly statistically different (p = 0.028). Job performance improved significantly in both the experimental group and the control group, so there was no statistical difference (p = 0.294). We therefore suggest that a critical reflection program be considered an essential tool for improving critical thinking and communication abilities among novice nurses who need to adapt to the clinical environment as quickly as possible. Further, we suggest conducting research into critical reflection programs among larger and more diverse samples.

Thin film type 248-nm bottom antireflective coatings

NASA Astrophysics Data System (ADS)

Enomoto, Tomoyuki; Nakayama, Keisuke; Mizusawa, Kenichi; Nakajima, Yasuyuki; Yoon, Sangwoong; Kim, Yong-Hoon; Kim, Young-Ho; Chung, Hoesik; Chon, Sang Mun

2003-06-01

A frequent problem encountered by photoresists during the manufacturing of semiconductor device is that activating radiation is reflected back into the photoresist by the substrate. So, it is necessary that the light reflection is reduced from the substrate. One approach to reduce the light reflection is the use of bottom anti-reflective coating (BARC) applied to the substrate beneath the photoresist layer. The BARC technology has been utilized for a few years to minimize the reflectivity. As the chip size is reduced to sub 0.13-micron, the photoresist thickness has to decrease with the aspect ratio being less than 3.0. Therefore, new Organic BARC is strongly required which has the minimum reflectivity with thinner BARC thickness and higher etch selectivity towards resist. SAMSUNG Electronics has developed the advanced Organic BARC with Nissan Chemical Industries, Ltd. and Brewer Science, Inc. for achieving the above purpose. As a result, the suitable high performance SNAC2002 series KrF Organic BARCs were developed. Using CF4 gas as etchant, the plasma etch rate of SNAC2002 series is about 1.4 times higher than that of conventional KrF resists and 1.25 times higher than the existing product. The SNAC2002 series can minimize the substrate reflectivity at below 40nm BARC thickness, shows excellent litho performance and coating properties.

Absorption and Reflection Contributions to the High Performance of Electromagnetic Waves Shielding Materials Fabricated by Compositing Leather Matrix with Metal Nanoparticles.

PubMed

Liu, Chang; Wang, Xiaoling; Huang, Xin; Liao, Xuepin; Shi, Bi

2018-04-25

Leather matrix (LM), a natural dielectric material, features a hierarchically suprafibrillar structure and abundant dipoles, which provides the possibility to dissipate electromagnetic waves (EW) energy via dipole relaxation combined with multiple diffuse reflections. Conventionally, metal-based materials are used as EW shielding materials due to that their high conductivity can reflect EW effectively. Herein, a lightweight and high-performance EW shielding composite with both absorption and reflection ability to EW was developed by coating metal nanoparticles (MNPs) onto LM. The as-prepared metal/LM membrane with only 4.58 wt % of coated MNPs showed excellent EW shielding effectiveness of ∼76.0 dB and specific shielding effectiveness of ∼200.0 dB cm 3 g -1 in the frequency range of 0.01-3.0 GHz, implying that more than 99.98% of EW was shielded. Further investigations indicated that the high shielding performances of the metal/LM membrane were attributed to the cooperative shielding mechanism between LM and the coating of MNPs.

Examining the role of self-regulation and emotion in clinical reasoning: Implications for developing expertise.

PubMed

Lajoie, Susanne P; Zheng, Juan; Li, Shan

2018-06-27

This paper explores the role that self-regulation and emotions play in establishing a clinical diagnosis in the context of solving a clinical case in BioWorld, a computer supported learning environment designed for medical students to practice clinical reasoning. Group differences between high and low performers were explored. The results revealed no group differences in overall measures of SRL but high performers spend more time than lows in a subcategory of the reflection phase (reflecting on prioritized evidence and results). A reciprocal role of emotions was demonstrated for clinical reasoning and predicted students' diagnostic performance. High performers showed less negative activating emotions than low performers.

Polarizing optics in a spider eye.

PubMed

Mueller, Kaspar P; Labhart, Thomas

2010-05-01

Many arthropods including insects and spiders exploit skylight polarization for navigation. One of the four eye pairs of the spider Drassodes cupreus is dedicated to detect skylight polarization. These eyes are equipped with a tapetum that strongly plane-polarizes reflected light. This effectively enhances the polarization-sensitivity of the photoreceptors, improving orientation performance. With a multidisciplinary approach, we demonstrate that D. cupreus exploits reflective elements also present in non-polarizing tapetal eyes of other species such as Agelena labyrinthica. By approximately orthogonal arrangement of two multilayer reflectors consisting of reflecting guanine platelets, the tapetum uses the mechanism of polarization by reflection for polarizing reflected light.

Identification of Terrestrial Reflectance From Remote Sensing

NASA Technical Reports Server (NTRS)

Alter-Gartenberg, Rachel; Nolf, Scott R.; Stacy, Kathryn (Technical Monitor)

2000-01-01

Correcting for atmospheric effects is an essential part of surface-reflectance recovery from radiance measurements. Model-based atmospheric correction techniques enable an accurate identification and classification of terrestrial reflectances from multi-spectral imagery. Successful and efficient removal of atmospheric effects from remote-sensing data is a key factor in the success of Earth observation missions. This report assesses the performance, robustness and sensitivity of two atmospheric-correction and reflectance-recovery techniques as part of an end-to-end simulation of hyper-spectral acquisition, identification and classification.

Interpreting vegetation reflectance measurements as a function of solar zenith angle

NASA Technical Reports Server (NTRS)

Kimes, D. S.; Smith, J. A.; Ranson, K. J.

1979-01-01

Spectral hemispherical-conical reflectances of a nadir looking sensor were taken throughout the day for a lodgepole pine and two grass canopies. Mathematical simulations of both spectral hemispherical-conical and bi-hemispherical reflectances were performed for two theoretical canopies of contrasting geometric structure. These results and comparisons with literature studies showed a great amount of variability of vegetation canopy reflectances as a function of solar zenith angle. Explanations for this variability are discussed and recommendations for further measurements are proposed.

A Comparison of the Effects of Reflective Learning Portfolios and Dialogue Journal Writing on Iranian EFL Learners' Accuracy in Writing Performance

ERIC Educational Resources Information Center

Hemmati, Fatemeh; Soltanpour, Fatemeh

2012-01-01

This study aimed at comparing the effects of reflective learning portfolio (RLP) and dialogue journal writing (DJW) on the Iranian EFL learners' grammatical accuracy in writing as well as their overall writing performance. 60 Iranian EFL learners between the ages of 17 to 30 who were studying at general English courses were selected based on their…

Effects of an Online Learning Community on Active and Reflective Learners' Learning Performance and Attitudes in a Face-to-Face Undergraduate Course

ERIC Educational Resources Information Center

Zhan, Zehui; Xu, Fuyin; Ye, Huiwen

2011-01-01

The purpose of this study was to examine the effects of an Online Learning Community (OLC) on active and reflective learners' learning performance and attitude in a face-to-face undergraduate digital design course. 814 freshmen in an introductory digital design course were randomly assigned to one of two treatments: one offered students an OLC,…

Effect of reflected and refracted signals on coherent underwater acoustic communication: results from the Kauai experiment (KauaiEx 2003).

PubMed

Rouseff, Daniel; Badiey, Mohsen; Song, Aijun

2009-11-01

The performance of a communications equalizer is quantified in terms of the number of acoustic paths that are treated as usable signal. The analysis uses acoustical and oceanographic data collected off the Hawaiian Island of Kauai. Communication signals were measured on an eight-element vertical array at two different ranges, 1 and 2 km, and processed using an equalizer based on passive time-reversal signal processing. By estimating the Rayleigh parameter, it is shown that all paths reflected by the sea surface at both ranges undergo incoherent scattering. It is demonstrated that some of these incoherently scattered paths are still useful for coherent communications. At range of 1 km, optimal communications performance is achieved when six acoustic paths are retained and all paths with more than one reflection off the sea surface are rejected. Consistent with a model that ignores loss from near-surface bubbles, the performance improves by approximately 1.8 dB when increasing the number of retained paths from four to six. The four-path results though are more stable and require less frequent channel estimation. At range of 2 km, ray refraction is observed and communications performance is optimal when some paths with two sea-surface reflections are retained.

How to perform first aid.

PubMed

Gloster, Annabella Satu; Johnson, Phillip John

2016-01-13

RATIONALE AND KEY POINTS: This article aims to help nurses to perform first aid in a safe, effective and patient-centred manner. First aid comprises a series of simple, potentially life-saving steps that an individual can perform with minimal equipment. Although it is not a legal requirement to respond to an emergency situation outside of work, nurses have a professional duty to respond and provide care within the limits of their competency. First aid is the provision of immediate medical assistance to an ill or injured person until definitive medical treatment can be accessed. First aid can save lives and it is essential that nurses understand the basic principles. REFLECTIVE ACTIVITY: Clinical skills articles can help update your practice and ensure it remains evidence based. Apply this article to your practice. Reflect on and write a short account of: 1. Your skill in performing first aid and any areas where you may need to extend your knowledge. 2. How reading this article will change your practice. Subscribers can upload their reflective accounts at: rcni.com/portfolio .

Reflective Behaviors under a Web-Based Portfolio Assessment Environment for High School Students in a Computer Course

ERIC Educational Resources Information Center

Chang, Chi-Cheng; Chen, Cheng-Chuan; Chen, Yi-Hui

2012-01-01

This research attempted to categorize reflection in a Web-based portfolio assessment using the Chinese Word Segmenting System (CWSS). Another aim of this research was to explore reflective performance in which individual differences were further examined. Participants were 45 eight-grade students from a junior high school taking a computer course.…

Preparation and performance evaluation of epoxy-based heat reflective coating for the pavement

NASA Astrophysics Data System (ADS)

Hu, B.; Liang, Y. H.; Guo, L. Y.; Jiang, T.

2017-04-01

According to the basic characteristics and composition of heat-reflective coating, combining with the functional requirements of road materials, the experiment selects the epoxy resin with good wear resistance and adhesive force as a film forming material, with TiO2, SiO2 and extinction powder as the main functional filler. The experiment gets a good formula with suitable viscosity, low glossiness and good cooling effect, optimizes by orthogonal experiment. The experiment evaluates the indoor and outdoor cooling effect of heat-reflective coating, and analyses the road performance of the coating. The results shows that the better heat-reflective coating formula included 12% of titanium dioxide, 4% of silica and 4% of extinction powder. When the dosage of coating is 0.8kg/m2, the indoor specimen of heat-reflective coating decrease the temperature of 12 ˜ 14°C, and the specimen under solar radiation can reduce the temperature of 7 ˜ 9°C. The pavement of heat-reflective coating has good wear resistance, but the road slip resistance partly declines. Therefore, it needs to add the anti-sliding particles to meet the safe driving requirements.

Effect of reflection losses on stationary dielectric-filled nonimaging concentrators

NASA Astrophysics Data System (ADS)

Madala, Srikanth; Boehm, Robert F.

2016-10-01

The effect of Fresnel reflection and total internal reflection (TIR) losses on the performance parameters in refractive solar concentrators has often been downplayed because most refractive solar concentrators are traditionally the imaging type, yielding a line or point image on the absorber surface when solely interacted with paraxial etendue ensured by solar tracking. Whereas, with refractive-type nonimaging solar concentrators that achieve two-dimensional (rectangular strip) focus or three-dimensional (circular or elliptical) focus through interaction with both paraxial and nonparaxial etendue within the acceptance angle, the Fresnel reflection and TIR losses are significant as they will affect the performance parameters and, thereby, energy collection. A raytracing analysis has been carried out to illustrate the effects of Fresnel reflection and TIR losses on four different types of stationary dielectric-filled nonimaging concentrators, namely V-trough, compound parabolic concentrator, compound elliptical concentrator, and compound hyperbolic concentrator. The refractive index (RI) of a dielectric fill material determines the acceptance angle of a solid nonimaging collector. Larger refractive indices yield larger acceptance angles and, thereby, larger energy collection. However, they also increase the Fresnel reflection losses. This paper also assesses the relative benefit of increasing RI from an energy collection standpoint.

Monitoring of mirror degradation of fluorescence detectors at the Pierre Auger Observatory due to dust sedimentation

NASA Astrophysics Data System (ADS)

Nozka, L.; Hiklova, H.; Horvath, P.; Hrabovsky, M.; Mandat, D.; Palatka, M.; Pech, M.; Ridky, J.; Schovanek, P.

2018-05-01

We present results of the monitoring method we have used to characterize the optical performance deterioration due to the dust of our mirror segments produced for fluorescence detectors used in astrophysics experiments. The method is based on the measurement of scatter profiles of reflected light. The scatter profiles and the reflectivity of the mirror segments sufficiently describe the performance of the mirrors from the perspective of reconstruction algorithms. The method is demonstrated on our mirror segments installed in frame of the Pierre Auger Observatory project. Although installed in air-conditioned buildings, both the dust sedimentation and the natural aging of the reflective layer deteriorate the optical throughput of the segments. In the paper, we summarized data from ten years of operation of the fluorescence detectors. During this time, we periodically measured in-situ scatter characteristics represented by the specular reflectivity and the reflectivity of the diffusion part at the wavelength of 670 nm of the segment surface (measured by means of the optical scatter technique as well). These measurements were extended with full Bidirectional Reflectance Distribution Functions (BRDF) profiles of selected segments made in the laboratory. Cleaning procedures are also discussed in the paper.

Sex differences in visuospatial abilities persist during induced hypogonadism

PubMed Central

Guerrieri, Gioia M.; Wakim, Paul G.; Keenan, P.A.; Schenkel, Linda A; Berlin, Kate; Gibson, Carolyn J.; Rubinow, David R.; Schmidt, Peter J.

2016-01-01

Background Despite well-established sex differences in the performance on tests of several cognitive domains (e.g., visuospatial ability), few studies in humans have evaluated if these sex differences are evident both in the presence of circulating sex hormones and during sex steroid hormonal suppression. Sex differences identified in the relative absence of circulating levels of estradiol and testosterone suggest that differences in brain structure or function exist independent of current hormonal environment and are more likely a reflection of differing developmental exposures and/or genetic substrates. Objective To evaluate cognitive performance in healthy eugonadal men and women before and again during GnRH agonist-induced hypogonadism. Methods Men (n = 16) and women (n = 15) without medical or psychiatric illness were matched for IQ. Cognitive tests were performed at baseline (when eugonadal) and after 68 weeks of GnRH agonist-induced gonadal suppression. The test batteries included measures of verbal and spatial memory, spatial ability, verbal fluency, motor speed/dexterity, and attention/concentration. Data were analyzed using repeated-measures models. Results During both eugonadism and hypogonadism, men performed significantly better than women on several measures of visuospatial performance including mental rotation, line orientation, Money Road Map, Porteus maze, and complex figure drawing. Although some test performances showed an effect of hormone treatment, the majority of these differences reflected an improved performance during hypogonadism compared with baseline (and probably reflected practice effects). Conclusion The well-documented male advantage in visuospatial performance, which we observed during eugonadal conditions, was maintained in the context of short-term suppression of gonadal function in both men and women. These findings suggest that, in humans, sex differences in visuospatial performance are not merely dependent on differences in the current circulating sex steroid environment. Thus sex differences in visuospatial performance in adulthood could reflect early developmental effects of sex steroid exposure or other environmental exposures differing across the sexes as our data confirm that these differences are independent of circulating estradiol or testosterone levels in men and women. PMID:26719236

Sex differences in visuospatial abilities persist during induced hypogonadism.

PubMed

Guerrieri, Gioia M; Wakim, Paul G; Keenan, P A; Schenkel, Linda A; Berlin, Kate; Gibson, Carolyn J; Rubinow, David R; Schmidt, Peter J

2016-01-29

Despite well-established sex differences in the performance on tests of several cognitive domains (e.g., visuospatial ability), few studies in humans have evaluated if these sex differences are evident both in the presence of circulating sex hormones and during sex steroid hormonal suppression. Sex differences identified in the relative absence of circulating levels of estradiol and testosterone suggest that differences in brain structure or function exist independent of current hormonal environment and are more likely a reflection of differing developmental exposures and/or genetic substrates. To evaluate cognitive performance in healthy eugonadal men and women before and again during GnRH agonist-induced hypogonadism. Men (n=16) and women (n=15) without medical or psychiatric illness were matched for IQ. Cognitive tests were performed at baseline (when eugonadal) and after 6-8 weeks of GnRH agonist-induced gonadal suppression. The test batteries included measures of verbal and spatial memory, spatial ability, verbal fluency, motor speed/dexterity, and attention/concentration. Data were analyzed using repeated-measures models. During both eugonadism and hypogonadism, men performed significantly better than women on several measures of visuospatial performance including mental rotation, line orientation, Money Road Map, Porteus maze, and complex figure drawing. Although some test performances showed an effect of hormone treatment, the majority of these differences reflected an improved performance during hypogonadism compared with baseline (and probably reflected practice effects). The well-documented male advantage in visuospatial performance, which we observed during eugonadal conditions, was maintained in the context of short-term suppression of gonadal function in both men and women. These findings suggest that, in humans, sex differences in visuospatial performance are not merely dependent on differences in the current circulating sex steroid environment. Thus sex differences in visuospatial performance in adulthood could reflect early developmental effects of sex steroid exposure or other environmental exposures differing across the sexes as our data confirm that these differences are independent of circulating estradiol or testosterone levels in men and women. Published by Elsevier Ltd.

Evaluation of a reflective coating for an organic scintillation detector

NASA Astrophysics Data System (ADS)

Tarancón, A.; Marin, E.; Tent, J.; Rauret, G.; Garcia, J. F.

2012-05-01

A reflective coating based on white paint, black paint and varnish has been evaluated to determine its reflective capabilities and its potential use in radioactivity detectors based on organic scintillators. Three different white paints, all of which were based on TiO2, were also tested to determine the one with the best performance and lowest radioactivity content. In a first experiment, we evaluated the capability of the reflective coating by measuring 90Sr/90Y with PSm in a polyethylene vial partially painted with EJ510 (Eljen Technology) reflective paint, black paint and varnish. In a second experiment, we compared the performance of the EJ510 to that of other white paints used for artistic purposes (Vallejo and Rembrandt). The results showed that, when a vial was only partially painted with the white paints (keeping a window free of paint to allow photons to exit), the efficiency and spectral distribution of the painted vial was similar to that of a non-painted vial. This behavior showed the efficiency of the reflective coatings. In terms of reflection capabilities, all of the tested paints were equivalent; however, the background was higher for the EJ510 paint. Analyses using high-resolution gamma spectroscopy indicated the presence of natural radionuclides (40K, 226Ra and 228Ra) in the EJ510. On the basis of the results (high reflection capabilities and the absence of radioactive impurities) and its lower cost, the Vallejo paint was selected as the white reflective paint. The final structure of the reflective coating was composed of five white paint layers, a black paint (to avoid external light entrance) and a layer of varnish (to protect the paints).

Investigation of reflective cracking mitigation techniques.

DOT National Transportation Integrated Search

2014-03-01

In the state of Florida, an asphalt rubber membrane interlayer (ARMI) has been commonly used as a reflective cracking (RC) mitigation method, but inconsistent performance of an ARMI has been observed in the field. Moreover, the Heavy Vehicle Simulato...

Reflection crack sealing study : final report.

DOT National Transportation Integrated Search

1969-06-01

This study is primarily an evaluation of the effectiveness of "Reclamite" when used as a sealant material for reflection cracks. A secondary objective was to determine the performance of our presently used material - cationic emulsified asphalt (RS-3...

Simultaneous generation of high-efficiency broadband asymmetric anomalous refraction and reflection waves with few-layer anisotropic metasurface

PubMed Central

Li, Zhancheng; Liu, Wenwei; Cheng, Hua; Liu, Jieying; Chen, Shuqi; Tian, Jianguo

2016-01-01

Optical metasurfaces consisting of single-layer nanostructures have immensely promising applications in wavefront control because they can be used to arbitrarily manipulate wave phase, and polarization. However, anomalous refraction and reflection waves have not yet been simultaneously and asymmetrically generated, and the limited efficiency and bandwidth of pre-existing single-layer metasurfaces hinder their practical applications. Here, a few-layer anisotropic metasurface is presented for simultaneously generating high-efficiency broadband asymmetric anomalous refraction and reflection waves. Moreover, the normal transmission and reflection waves are low and the anomalous waves are the predominant ones, which is quite beneficial for practical applications such as beam deflectors. Our work provides an effective method of enhancing the performance of anomalous wave generation, and the asymmetric performance of the proposed metasurface shows endless possibilities in wavefront control for nanophotonics device design and optical communication applications. PMID:27762286

Precise Control of Vertical-Cavity Surface-Emitting Laser Structural Growth Using Molecular Beam Epitaxy In Situ Reflectance Monitor

NASA Astrophysics Data System (ADS)

Mizutani, Mitsuhiro; Teramae, Fumiharu; Takeuchi, Kazutaka; Murase, Tatsunori; Naritsuka, Shigeya; Maruyama, Takahiro

2006-04-01

A vertical-cavity surface-emitting laser (VCSEL) was fabricated using a in situ reflectance monitor by molecular beam epitaxy (MBE). Both the center wavelength of the stop band of the distributed Bragg reflector (DBR) and the resonant wavelength of the optical cavity were successfully controlled using the monitor. However, these wavelengths shifted with decreasing substrate temperature after the growth, which could be reasonably explained by the temperature dependence of refractive index. Therefore, it is necessary to set a target wavelength at a growth temperature, considering the change. The desirable laser performance of the VCSEL fabricated from the wafer indicates marked increases in the controllability and reproducibility of growth with the aid of the in situ reflectance monitor. Since it can directly measure the optical properties of the grown layers, the reflectance monitor greatly helps in the fabrication of a structure with the designed optical performance.

MODIS Solar Diffuser On-orbit Performance

NASA Technical Reports Server (NTRS)

Xiong, Xiaoxiong; Chen, H.; Choi, T.; Sun, J.; Angal, A.

2008-01-01

MODIS is a key instrument for the NASA Earth Observing System (EOS), currently operated on both the Terra and Aqua missions. Each MODIS instrument has 20 reflective solar bands (RSBs) and 16 thermal emissive bands (TEBs). MODIS RSB on-orbit calibration is reflectance based using an on-board solar diffuser (SD). The SD bi-directional reflectance factors (BRFs) were characterized pre-launch using reference diffuser samples, which are traceable to NIST reflectance standards. The SD BRF on-orbit degradation (or change) is tracked by another onboard device, called the solar diffuser stability monitor (SDSM). The SDSM is operated during each scheduled SD calibration event, making alternate observations of direct sunlight and the diffusely reflected sunlight from the SD. The time series of the ratios of SDSM's SD view to its Sun view provide SD degradation information. This paper presents and compares the Terra and Aqua MODIS SD on-orbit performance. Results show that the SD on-orbit degradation depends on the amount of solar exposure of the SD plate. In addition, it is strongly wavelengthdependent, with a larger degradation rate at shorter wavelengths. For Terra MODIS, an SD door anomaly occurred in May 2003 that led to a decision to fix the door permanently at an "open" position. Since then, the SD degradation rate has significantly increased due to more frequent solar exposure. As expected, the SD on-orbit performance directly impacts the RSB calibration performance. The lessons learned from MODIS on-orbit calibration will provide useful insights into the development and operation of future SD calibration systems.

Handheld Reflective Foil Emissometer with 0.007 Absolute Accuracy at 0.05

NASA Astrophysics Data System (ADS)

van der Ham, E. W. M.; Ballico, M. J.

2014-07-01

The development and performance of a handheld emissometer for the measurement of the emissivity of highly reflective metallic foils used for the insulation of domestic and commercial buildings are described. Reflective roofing insulation based on a thin coating of metal on a more robust substrate is very widely used in hotter climates to reduce the radiant heat transfer between the ceiling and roof in commercial and residential buildings. The required normal emissivity of these foils is generally below 0.05, so stray reflected ambient infrared radiation (IR) makes traditional reflectance-based measurements of emissivity very difficult to achieve with the required accuracy. Many manufacturers apply additional coatings onto the metallic foil to reduce visible glare during installation on a roof, and to provide protection to the thin reflective layer; however, this layer can also substantially increase the IR emissivity. The system as developed at the National Measurement Institute, Australia (NMIA) is based on the principle of measurement of the modulation in thermal infrared radiation, as the sample is thermally modulated by hot and cold air streams. A commercial infrared to band radiation thermometer with a highly specialized stray and reflected radiation shroud attachment is used as the detector system, allowing for convenient handheld field measurements. The performance and accuracy of the system have been compared with NMIA's reference emissometer systems for a number of typical material samples, demonstrating its capability to measure the absolute thermal emissivity of these very highly reflective foils with an uncertainty of better than.

Reflective Coating on Fibrous Insulation for Reduced Heat Transfer

NASA Technical Reports Server (NTRS)

Hass, Derek D.; Prasad, B. Durga; Glass, David E.; Wiedemann, Karl E.

1997-01-01

Radiative heat transfer through fibrous insulation used in thermal protection systems (TPS) is significant at high temperatures (1200 C). Decreasing the radiative heat transfer through the fibrous insulation can thus have a major impact on the insulating ability of the TPS. Reflective coatings applied directly to the individual fibers in fibrous insulation should decrease the radiative heat transfer leading to an insulation with decreased effective thermal conductivity. Coatings with high infrared reflectance have been developed using sol-gel techniques. Using this technique, uniform coatings can be applied to fibrous insulation without an appreciable increase in insulation weight or density. Scanning electron microscopy, Fourier Transform infrared spectroscopy, and ellipsometry have been performed to evaluate coating performance.

The making of expert clinicians: reflective practice.

PubMed

Maestre, J M; Szyld, D; Del Moral, I; Ortiz, G; Rudolph, J W

2014-05-01

Debriefing is a rigorous reflection process which helps trainees recognize and resolve clinical and behavioral dilemmas raised by a clinical case. This approach emphasizes eliciting trainees'assumptions about the situation and their reasons for performing as they did (mental models). It analyses their impact on actions, to understand if it is necessary to maintain them or construct new ones that may lead to better performance in the future. It blends evidence and theory from education research, the social and cognitive sciences, and experience drawn from conducting and teaching debriefing to clinicians worldwide, on how to improve professional effectiveness through "reflective practice". Copyright © 2013 Elsevier España, S.L. All rights reserved.

Long-term practice effects on a new skilled motor learning: an electrophysiological study.

PubMed

Fattapposta, F; Amabile, G; Cordischi, M V; Di Venanzio, D; Foti, A; Pierelli, F; D'Alessio, C; Pigozzi, F; Parisi, A; Morrocutti, C

1996-12-01

Cortical functions concerned with the execution of skilled movements can be studied through complex interactive tasks. Skilled performance task (SPT) offers the greatest deal of information about the electrophysiological components reflecting pre-programming, execution of the movement and control of the results. Overall, these components are indicated as "movement-related brain macropotentials' (MRBMs). Among them, Bereitschaftspotential (BP) reflects cerebral processes related to the preparation of movement and skilled performance positivity (SPP) reflects control processes on the result of performance. There is some evidence supporting a training effect on MRBMs, but less clear is whether long-term practice of a skilled activity could modify learning strategies of a new skilled task. We recorded MRBMs in subjects trained for a long time to perform a highly skillful athletic activity, i.e. gun shooting, and in a group of control subjects without any former experience in skilled motor activities. Our findings demonstrated the existence of a relationship between pre-programming and performance control, as suggested by decrease of BP amplitude and increase of SPP amplitude in presence of high levels of performance. Long-term practice seems to develop better control models on performance, that reduce the need of a high mental effort in pre-programming a skilled action.

Evaluation of emergency department performance - a systematic review on recommended performance and quality-in-care measures.

PubMed

Sørup, Christian Michel; Jacobsen, Peter; Forberg, Jakob Lundager

2013-08-09

Evaluation of emergency department (ED) performance remains a difficult task due to the lack of consensus on performance measures that reflects high quality, efficiency, and sustainability. To describe, map, and critically evaluate which performance measures that the published literature regard as being most relevant in assessing overall ED performance. Following the PRISMA guidelines, a systematic literature review of review articles reporting accentuated ED performance measures was conducted in the databases of PubMed, Cochrane Library, and Web of Science. Study eligibility criteria includes: 1) the main purpose was to discuss, analyse, or promote performance measures best reflecting ED performance, 2) the article was a review article, and 3) the article reported macro-level performance measures, thus reflecting an overall departmental performance level. A number of articles addresses this study's objective (n = 14 of 46 unique hits). Time intervals and patient-related measures were dominant in the identified performance measures in review articles from US, UK, Sweden and Canada. Length of stay (LOS), time between patient arrival to initial clinical assessment, and time between patient arrivals to admission were highlighted by the majority of articles. Concurrently, "patients left without being seen" (LWBS), unplanned re-attendance within a maximum of 72 hours, mortality/morbidity, and number of unintended incidents were the most highlighted performance measures that related directly to the patient. Performance measures related to employees were only stated in two of the 14 included articles. A total of 55 ED performance measures were identified. ED time intervals were the most recommended performance measures followed by patient centeredness and safety performance measures. ED employee related performance measures were rarely mentioned in the investigated literature. The study's results allow for advancement towards improved performance measurement and standardised assessment across EDs.

Design of a force reflecting hand controller for space telemanipulation studies

NASA Technical Reports Server (NTRS)

Paines, J. D. B.

1987-01-01

The potential importance of space telemanipulator systems is reviewed, along with past studies of master-slave manipulation using a generalized force reflecting master arm. Problems concerning their dynamic interaction with the human operator have been revealed in the use of these systems, with marked differences between 1-g and simulated weightless conditions. A study is outlined to investigate the optimization of the man machine dynamics of master-slave manipulation, and a set of specifications is determined for the apparatus necessary to perform this investigation. This apparatus is a one degree of freedom force reflecting hand controller with closed loop servo control which enables it to simulate arbitrary dynamic properties to high bandwidth. Design of the complete system and its performance is discussed. Finally, the experimental adjustment of the hand controller dynamics for smooth manual control performance with good operator force perception is described, resulting in low inertia, viscously damped hand controller dynamics.

Coupled thermo-elastic and optical performance analyses of a reflective baffle for the BepiColombo laser altimeter (BELA) receiver

NASA Astrophysics Data System (ADS)

Heesel, E.; Weigel, T.; Lochmatter, P.; Rugi Grond, E.

2017-11-01

For the BepiColombo mission, the extreme thermal environment around Mercury requires good heat shields for the instruments. The BepiColombo Laser altimeter (BELA) Receiver will be equipped with a specular reflective baffle in order to limit the solar power impact. The design uses a Stavroudis geometry with alternating elliptical and hyperbolic vanes to reflect radiation at angles >38° back into space. The thermal loads on the baffle lead to deformations, and the resulting changes in the optical performance can be modeled by ray-tracing. Conventional interfaces, such as Zernike surface fitting, fail to provide a proper import of the mechanical distortions into optical models. We have studied alternative models such as free form surface representations and compared them to a simple modeling approach with straight segments. The performance merit is presented in terms of the power rejection ratio and the absence of specular stray-light.

Actualization of the Onion Model of Reflection in Turkish English Language Instructors' Practices: A Case Study

ERIC Educational Resources Information Center

Ekizer, Feyza Nur; Cephe, Pasa Tevfik

2017-01-01

Teachers spend so much time and energy focused on their students' progress that they often forget to consider their own performances. Self-reflection here is a very valuable tool that helps make the teacher aware of how he/she is teaching, which in turn makes him/her a better teacher. Teaching without reflection is teaching blind-without any…

A reflective optical transport system for ultraviolet Thomson scattering from electron plasma waves on OMEGA.

PubMed

Katz, J; Boni, R; Sorce, C; Follett, R; Shoup, M J; Froula, D H

2012-10-01

A reflective optical transport system has been designed for the OMEGA Thomson-scattering diagnostic. A Schwarzschild objective that uses two concentric spherical mirrors coupled to a Pfund objective provides diffraction-limited imaging across all reflected wavelengths. This enables the operator to perform Thomson-scattering measurements of ultraviolet (0.263 μm) light scattered from electron plasma waves.

Performance of large aperture tapered fiber phase conjugate mirror with high pulse energy and 1-kHz repetition rate.

PubMed

Zhao, Zhigang; Dong, Yantao; Pan, Sunqiang; Liu, Chong; Chen, Jun; Tong, Lixin; Gao, Qingsong; Tang, Chun

2012-01-16

A large aperture fused silica tapered fiber phase conjugate mirror is presented with a maximum 70% stimulated Brillouin scattering (SBS) reflectivity, which is obtained with 1 kHz repetition rate, 15 ns pulse width and 38 mJ input pulse energy. To the best of our knowledge, this is the highest SBS reflectivity ever reported by using optical fiber as a phase conjugate mirror for such high pulse repetition rate (1 kHz) and several tens of millijoule (mJ) input pulse energy. The influences of fiber end surface quality and pump pulse widths on SBS reflectivity are investigated experimentally. The results show that finer fiber end surface quality and longer input pulse widths are preferred for obtaining higher SBS reflectivity with higher input pulse energy. Double passing amplification experiments are also performed. 52 mJ pulse energy is achieved at 1 kHz repetition rate, with a reflected SBS pulse width of 1.5 ns and a M(2) factor of 2.3. The corresponding peak power reaches 34.6 MW. Obvious beam quality improvement is observed.

Neural correlates of facilitations in face learning by selective caricaturing of facial shape or reflectance.

PubMed

Itz, Marlena L; Schweinberger, Stefan R; Schulz, Claudia; Kaufmann, Jürgen M

2014-11-15

Spatially caricatured faces were recently shown to benefit face learning (Schulz et al., 2012a). Moreover, spatial information may be particularly important for encoding unfamiliar faces, but less so for recognizing familiar faces (Kaufmann et al., 2013). To directly test the possibility of a major role of reflectance information for the recognition of familiar faces, we compared effects of selective photorealistic caricaturing in either shape or reflectance on face learning and recognition. Participants learned 3D-photographed faces across different viewpoints, and different images were presented at learning and test. At test, performance benefits for both types of caricatures were modulated by familiarity: Benefits for learned faces were substantially larger for reflectance caricatures, whereas benefits for novel faces were numerically larger for shape caricatures. ERPs confirmed a consistent reduction of the occipitotemporal P200 (200-240 ms) by shape caricaturing, whereas the most prominent effect of reflectance caricaturing was seen in an enhanced posterior N250 (240-400 ms), a component that has been related to the activation of acquired face representations. Our results suggest that performance benefits for face learning caused by distinctive spatial versus reflectance information are mediated by different neural processes with different timing and support a prominent role of reflectance for the recognition of learned faces. Copyright © 2014 Elsevier Inc. All rights reserved.

Consolidated fuel reprossing program: The implications of force reflection for teleoperation in space

NASA Technical Reports Server (NTRS)

Draper, John V.; Herndon, Joseph N.; Moore, Wendy E.

1987-01-01

Previous research on teleoperator force feedback is reviewed and results of a testing program which assessed the impact of force reflection on teleoperator task performance are reported. Force relection is a type of force feedback in which the forces acting on the remote portion of the teleoperator are displayed to the operator by back-driving the master controller. The testing program compared three force reflection levels: 4 to 1 (four units of force on the slave produce one unit of force at the master controller), 1 to 1, and infinity to 1 (no force reflection). Time required to complete tasks, rate of occurrence of errors, the maximum force applied to tasks components, and variability in forces applied to components during completion of representative remote handling tasks were used as dependent variables. Operators exhibited lower error rates, lower peak forces, and more consistent application of forces using force relection than they did without it. These data support the hypothesis that force reflection provides useful information for teleoperator users. The earlier literature and the results of the experiment are discussed in terms of their implications for space based teleoperator systems. The discussion described the impact of force reflection on task completion performance and task strategies, as suggested by the literature. It is important to understand the trade-offs involved in using telerobotic systems with and without force reflection.

Thin film and high-etch-rate type 248-nm bottom antireflective coatings

NASA Astrophysics Data System (ADS)

Enomoto, Tomoyuki; Takei, Satoshi; Kishioka, Takahiro; Hatanaka, Tadashi; Sakamoto, Rikimaru; Nakajima, Yasuyuki

2004-05-01

A frequent problem encountered by photoresists during the manufacturing of semiconductor device is that activating radiation is reflected back into the photoresist by the substrate. So, it is necessary that the light reflection is reduced from the substrate. One approach to reduce the light reflection is the use of bottom anti-reflective coating (BARC) applied to the substrate beneath the photoresist layer. The BARC technology has been utilized for a few years to minimize the reflectivity. As the chip size is reduced to sub 0.13 micron, the photoresist thickness has to decrease with the aspect ratio being less than 3.0. Therefore, new Organic BARC is strongly required which has the minimum reflectivity with thinner BARC thickness and higher etch selectivity toward resists. Nissan Chemical Industries, Ltd. and Brewer Science, Inc. have developed the advanced Organic BARC for achieving the above purpose. As a result, the suitable high performance NCA3000 series 248nm Organic BARCs were developed. Using CF4 gas as etchant, the plasma etch rate of NCA3000 series is about 1.4-1.6 times higher than that of conventional 248nm resists and 1.1-1.2 times higher than that of the existing product. The NCA3000 series can minimize the substrate reflectivity at below 45nm BARC thickness, shows excellent litho performance and coating properties.

Laboratory Measurement of Bidirectional Reflectance of Radiometric Tarps

NASA Technical Reports Server (NTRS)

Knowlton, Kelly

2006-01-01

Objectives: a) To determine the magnitude of radiometric tarp BRDF; b) To determine whether an ASD FieldSpec Pro spectroradiometer can be used to perform the experiment. Radiometric tarps with nominal reflectance values of 52%, 35%, and 3.5%, deployed for IKONOS. QuickBird, and OrbView-3 overpasses Ground-based spectroradiometric measurements of tarp and Spectralon@ panel taken during overpass using ASD FieldSpec Pro spectroradiometer, and tarp reflectance calculated. Reflectance data used in atmospheric radiative transfer model (MODTRAN) to predict satellite at-sensor radiance for radiometric calibration. Reflectance data also used to validate atmospheric correction of high-spatial-resolution multispectral image products

Neutron reflecting supermirror structure

DOEpatents

Wood, James L.

1992-01-01

An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources. One layer of each set of bilayers consist of titanium, and the second layer of each set of bilayers consist of an alloy of nickel with carbon interstitially present in the nickel alloy.

Use of high intensity reflective materials in highway signing : a literature review.

DOT National Transportation Integrated Search

1973-01-01

This literature review summarizes the research findings relative to the performance of high intensity (encapsulated lens) reflective sheeting. The study reveals that the brightness and durability of the encapsulated lens material are superior to thos...

Assessment of asphalt interlayer designed on jointed concrete.

DOT National Transportation Integrated Search

2014-11-01

Reflective cracking in hot mix asphalt (HMA) overlays has been a common cause of poor pavement performance in Iowa for : many years. Reflective cracks commonly occur in HMA overlays when deteriorated portland cement concrete is paved over with : HMA....

The study of multilayer anti-reflection coating in InSb focal plane detector

NASA Astrophysics Data System (ADS)

Zheng, Kelin; Wei, Peng; Wang, Liwen; Su, Xianjun; Wang, Haizhen

2016-10-01

In manufacturing of InSb focal plane detector, InSb chip have to be polished from backside to reduce its thickness and then be plated a layer of coating to decrease its reflection (enhance its transmittance) for infrared ray. Moreover, the anti-reflection coating has to be multilayer for more anti-reflection bandwidth. In this article, it is introduced that the optimal design of triple layer λ/4 anti-reflection coating——the anodic oxide, SiNx and MgF2. The best thickness range of each layer and its theoretical reflective index are calculated from simulation software, until the refractive index of each layer has been measured by ellipsometer. And then the transmissivity and reflectivity of the triple layer coating are measured for testing and verifying its performance on the transmittance and reflection. In the end, the anti-reflective effect of the triple layer coating and monolayer SiNx coating are respectively measured and compared by infrared focal plane array measurement system. And it is showed that this triple layer coating achieved more anti-reflection bandwidth and better anti reflective effect.

Gaze Behavior of Gymnastics Judges: Where Do Experienced Judges and Gymnasts Look While Judging?

PubMed

Pizzera, Alexandra; Möller, Carsten; Plessner, Henning

2018-03-01

Gymnastics judges and former gymnasts have been shown to be quite accurate in detecting errors and accurately judging performance. The purpose of the current study was to examine if this superior judging performance is reflected in judges' gaze behavior. Thirty-five judges were asked to judge 21 gymnasts who performed a skill on the vault in a video-based test. Classifying 1 sample on 2 different criteria, judging performance and gaze behavior were compared between judges with a higher license level and judges with a lower license level and between judges who were able to perform the skill (specific motor experience [SME]) and those who were not. The results revealed better judging performance among judges with a higher license level compared with judges with a lower license level and more fixations on the gymnast during the whole skill and the landing phase, specifically on the head and arms of the gymnast. Specific motor experience did not result in any differences in judging performance; however, judges with SME showed similar gaze patterns to those of judges with a high license level, with 1 difference in their increased focus on the gymnasts' feet. Superior judging performance seems to be reflected in a specific gaze behavior. This gaze behavior appears to partly stem from judges' own sensorimotor experiences for this skill and reflects the gymnasts' perspective onto the skill.

New advances in the partial-reflection-drifts experiment using microprocessors

NASA Technical Reports Server (NTRS)

Ruggerio, R. L.; Bowhill, S. A.

1982-01-01

Improvements to the partial reflection drifts experiment are completed. The results of the improvements include real time processing and simultaneous measurements of the D region with coherent scatter. Preliminary results indicate a positive correlation between drift velocities calculated by both methods during a two day interval. The possibility now exists for extended observations between partial reflection and coherent scatter. In addition, preliminary measurements could be performed between partial reflection and meteor radar to complete a comparison of methods used to determine velocities in the D region.

Multimodal signals: ultraviolet reflectance and chemical cues in stomatopod agonistic encounters

PubMed Central

Marshall, N. Justin; Lewis, Sara M.

2016-01-01

Complex signals are commonly used during intraspecific contests over resources to assess an opponent's fighting ability and/or aggressive state. Stomatopod crustaceans may use complex signals when competing aggressively for refuges. Before physical attacks, stomatopods assess their opponents using chemical cues and perform threat displays showing a coloured patch, the meral spot. In some species, this spot reflects UV. However, despite their complex visual system with up to 20 photoreceptor classes, we do not know if stomatopods use chromatic or achromatic signals in contests. In a field study, we found that Neogonodactylus oerstedii meral spot luminance varies with sex, habitat and, more weakly, body length. Next, we conducted an experimental manipulation which demonstrated that both chemical cues and chromatic signals are used during contests. In the absence of chemical cues, stomatopods approached an occupied refuge more quickly and performed offensive behaviours at a lower rate. When UV reflectance was absent, stomatopods performed offensive behaviours more frequently and contest duration trended towards shorter fights. These results provide new evidence that UV reflectance and/or visible spectrum luminance is used to amplify threat displays. Our results are the first to demonstrate that chemical and chromatic cues comprise a multimodal signal in stomatopod contests. PMID:27853613

Singer Responses to Sound Fields with a Simulated Reflection

NASA Astrophysics Data System (ADS)

NOSON, D.; SATO, S.; SAKAI, H.; ANDO, Y.

2000-04-01

While numerous recent studies have reported results concerning improvements to stage acoustics for orchestral performers, the preferred acoustical conditions on performing stages for singers has received limited attention in the past 20 years. A series of acoustical modifications have been proposed for a Seattle church to improve the acoustics for both the listeners and the performing choir. An on-site preliminary study was made to determine what acoustical changes might be important to singers. During solo fast-tempo singing and duet singing, singer preference increased with simulated short-delay reflections. The results suggest a potential for new reflectors to produce noticeable improvement in the choir acoustics. Subsequently, a solo singer study was conducted to establish preferred range of time delays for a single-simulated reflection. When singing faster-tempo music, the consensus of preference is statistically significant and the preferred delay averages 20 ms, while with a slow-tempo piece, the singers were not consistent in their judgment of preference and a strong individual variability predominated in the pair-comparison tests. The results point the way for an examination of a wider range of time delays and music motifs to acquire a clearer picture of consensus and individual preference for time-delayed reflections.

Hard x-ray characterization of a HEFT single-reflection prototype

NASA Astrophysics Data System (ADS)

Christensen, Finn E.; Craig, William W.; Hailey, Charles J.; Jimenez-Garate, Mario A.; Windt, David L.; Harrison, Fiona A.; Mao, Peter H.; Ziegler, Eric; Honkimaki, Veijo; Sanchez del Rio, Manuel; Freund, Andreas K.; Ohler, M.

2000-07-01

We have measured the hard X-ray reflectivity and imaging performance from depth graded W/Si multilayer coated mirror segments mounted in a single reflection cylindrical prototype for the hard X-ray telescopes to be flown on the High Energy Focusing Telescope (HEFT) balloon mission. Data have been obtained in the energy range from 18 - 170 keV at the European Synchrotron Radiation Facility and at the Danish Space Research Institute at 8 keV. The modeling of the reflectivity data demonstrate that the multilayer structure can be well described by the intended power law distribution of the bilayer thicknesses optimized for the telescope performance and we find that all the data is consistent with an interfacial width of 4.5 angstroms. We have also demonstrated that the required 5% uniformity of the coatings is obtained over the mirror surface and we have shown that it is feasible to use similar W/Si coatings for much higher energies than the nominal energy range of HEFT leading the way for designing Gamma-ray telescopes for future astronomical applications. Finally we have demonstrate 35 arcsecond Half Power Diameter imaging performance of the one bounce prototype throughout the energy range of the HEFT telescopes.

The Dragon and Uncle Sam: Shaping the World for Prosperity or Destruction?

DTIC Science & Technology

2012-02-03

student academic research paper are those of the author and do not reflect the official policy or position of the Department of the Army, Department...5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER...expressed in this student academic research paper are those of the author and do not reflect the official policy or position of the Department of the Army

Effects of communication on the performance of nursing students during the simulation of an emergency situation.

PubMed

Chapelain, Pascal; Morineau, Thierry; Gautier, Claudie

2015-11-01

To explore how nursing performance is impacted by different forms of team communication including a message transmitted through an earpiece which triggers reflective thinking in the simulation of a deteriorating patient situation. Communication can either support team performance or produce interruptions potentially leading to error. Today, technology offers the opportunity to use devices that can permit communication. An experimental protocol was used with quantitative and qualitative analyses. Pairs of nursing students (N = 26) were dispatched to either an experimental group having to wear an earpiece priming reflective thinking, or to a control group. The study was conducted between October 2013-April 2014. The number of spontaneous information exchanges between pairs of participants was positively correlated with overall performance (actions performed and physician call) and with actions performed at the right moment. The number of questions in the team was positively correlated with overall action performance. No quantitative effect of the earpiece message on the performance indicators was found. But, a qualitative observation showed that this message can allow for error avoidance. Subjective evaluation of the earpiece as an aid was negatively correlated with overall action performance. Its evaluation as a disturbance was also negatively correlated with the measurement of actions performed at the right moment. The ability to exchange information and to ask questions seems to contribute to performance in care delivery. The use of communication devices to trigger reflective thinking must be studied in more depth to assess their capacity to improve performance. © 2015 John Wiley & Sons Ltd.

Small Engine Technology (SET) Task 23 ANOPP Noise Prediction for Small Engines, Wing Reflection Code

NASA Technical Reports Server (NTRS)

Lieber, Lysbeth; Brown, Daniel; Golub, Robert A. (Technical Monitor)

2000-01-01

The work performed under Task 23 consisted of the development and demonstration of improvements for the NASA Aircraft Noise Prediction Program (ANOPP), specifically targeted to the modeling of engine noise enhancement due to wing reflection. This report focuses on development of the model and procedure to predict the effects of wing reflection, and the demonstration of the procedure, using a representative wing/engine configuration.

Land Surface Reflectance Retrieval from Hyperspectral Data Collected by an Unmanned Aerial Vehicle over the Baotou Test Site

PubMed Central

Duan, Si-Bo; Li, Zhao-Liang; Tang, Bo-Hui; Wu, Hua; Ma, Lingling; Zhao, Enyu; Li, Chuanrong

2013-01-01

To evaluate the in-flight performance of a new hyperspectral sensor onboard an unmanned aerial vehicle (UAV-HYPER), a comprehensive field campaign was conducted over the Baotou test site in China on 3 September 2011. Several portable reference reflectance targets were deployed across the test site. The radiometric performance of the UAV-HYPER sensor was assessed in terms of signal-to-noise ratio (SNR) and the calibration accuracy. The SNR of the different bands of the UAV-HYPER sensor was estimated to be between approximately 5 and 120 over the homogeneous targets, and the linear response of the apparent reflectance ranged from approximately 0.05 to 0.45. The uniform and non-uniform Lambertian land surface reflectance was retrieved and validated using in situ measurements, with root mean square error (RMSE) of approximately 0.01–0.07 and relative RMSE of approximately 5%–12%. There were small discrepancies between the retrieved uniform and non-uniform Lambertian land surface reflectance over the homogeneous targets and under low aerosol optical depth (AOD) conditions (AOD = 0.18). However, these discrepancies must be taken into account when adjacent pixels had large land surface reflectance contrast and under high AOD conditions (e.g. AOD = 1.0). PMID:23785513

Spectra analysis of nonuniform FBG-based acousto-optic modulator by using Fourier mode coupling theory.

PubMed

Liu, Chao; Pei, Li; Li, Zhuoxuan; Ning, Tigang; Yu, Shaowei; Kang, Zexin

2013-05-10

Fourier mode coupling theory was first employed in the spectral analysis of several nonuniform fiber Bragg grating (FBG)-based acousto-optic modulators (NU-FBG-AOMs) with the effects of Gaussian-apodization (GA), phase shift (PS), and linear chirp (LC). Because of the accuracy and simplicity of the algorithm applied in this model, the modulation performances of these modulators can be acquired effectively and efficiently. Based on the model, the reflected spectra of these modulators were simulated under various acoustic frequencies and acoustically induced strains. The simulation results of the GA-FBG-AOM and PS-FBG-AOM showed that the wavelength spacing between the primary reflection peak and the secondary reflection peak is proportional to the acoustic frequency, and the reflectivity of reflection peaks depends on the acoustically induced strains. But for the LC-FBG-AOM, the wavelength spacing between the neighboring reflection peaks increased linearly and inversely with the acoustic frequency, and the extinction ratio of each peak relates to the acoustically induced strain. These numerical analysis results, which were effectively used in the designs and fabrications of these NU-FBG-AOMs, can broaden the AOM-based application scope and shed light on the performance optimization of optical wavelength-division multiplex system.

Desert soil clay content estimation using reflectance spectroscopy preprocessed by fractional derivative

PubMed Central

Tiyip, Tashpolat; Ding, Jianli; Zhang, Dong; Liu, Wei; Wang, Fei; Tashpolat, Nigara

2017-01-01

Effective pretreatment of spectral reflectance is vital to model accuracy in soil parameter estimation. However, the classic integer derivative has some disadvantages, including spectral information loss and the introduction of high-frequency noise. In this paper, the fractional order derivative algorithm was applied to the pretreatment and partial least squares regression (PLSR) was used to assess the clay content of desert soils. Overall, 103 soil samples were collected from the Ebinur Lake basin in the Xinjiang Uighur Autonomous Region of China, and used as data sets for calibration and validation. Following laboratory measurements of spectral reflectance and clay content, the raw spectral reflectance and absorbance data were treated using the fractional derivative order from the 0.0 to the 2.0 order (order interval: 0.2). The ratio of performance to deviation (RPD), determinant coefficients of calibration (Rc2), root mean square errors of calibration (RMSEC), determinant coefficients of prediction (Rp2), and root mean square errors of prediction (RMSEP) were applied to assess the performance of predicting models. The results showed that models built on the fractional derivative order performed better than when using the classic integer derivative. Comparison of the predictive effects of 22 models for estimating clay content, calibrated by PLSR, showed that those models based on the fractional derivative 1.8 order of spectral reflectance (Rc2 = 0.907, RMSEC = 0.425%, Rp2 = 0.916, RMSEP = 0.364%, and RPD = 2.484 ≥ 2.000) and absorbance (Rc2 = 0.888, RMSEC = 0.446%, Rp2 = 0.918, RMSEP = 0.383% and RPD = 2.511 ≥ 2.000) were most effective. Furthermore, they performed well in quantitative estimations of the clay content of soils in the study area. PMID:28934274

Cognitive Reflection and the Diligent Worker: An Experimental Study of Millennials

PubMed Central

Corgnet, Brice; Hernán Gonzalez, Roberto; Mateo, Ricardo

2015-01-01

Recent studies have shown that despite crucially needing the creative talent of millennials (people born after 1980) organizations have been reluctant to hire young workers because of their supposed lack of diligence. We propose to help resolve this dilemma by studying the determinants of task performance and shirking behaviors of millennials in a laboratory work environment. We find that cognitive ability is a good predictor of task performance in line with previous literature. In contrast with previous research, personality traits do not consistently predict either task performance or shirking behaviors. Shirking behaviors, as measured by the time participants spent browsing the internet for non-work purposes (Cyberloafing), were only explained by the performance on the Cognitive Reflection Test (CRT). This finding echoes recent research in cognitive psychology according to which conventional measures of cognitive ability only assess a narrow concept of rational thinking (the algorithmic mind) that fails to capture individuals’ capacity to reflect and control their impulses. Our findings suggest that hiring diligent millennials relies on the use of novel cognitive measures such as CRT in lieu of standard personality and intelligence tests. PMID:26545244

Cognitive Reflection and the Diligent Worker: An Experimental Study of Millennials.

PubMed

Corgnet, Brice; Hernán Gonzalez, Roberto; Mateo, Ricardo

2015-01-01

Recent studies have shown that despite crucially needing the creative talent of millennials (people born after 1980) organizations have been reluctant to hire young workers because of their supposed lack of diligence. We propose to help resolve this dilemma by studying the determinants of task performance and shirking behaviors of millennials in a laboratory work environment. We find that cognitive ability is a good predictor of task performance in line with previous literature. In contrast with previous research, personality traits do not consistently predict either task performance or shirking behaviors. Shirking behaviors, as measured by the time participants spent browsing the internet for non-work purposes (Cyberloafing), were only explained by the performance on the Cognitive Reflection Test (CRT). This finding echoes recent research in cognitive psychology according to which conventional measures of cognitive ability only assess a narrow concept of rational thinking (the algorithmic mind) that fails to capture individuals' capacity to reflect and control their impulses. Our findings suggest that hiring diligent millennials relies on the use of novel cognitive measures such as CRT in lieu of standard personality and intelligence tests.

Minimization of reflection cracks, Route 17, Gloucester County : installation report 1976.

DOT National Transportation Integrated Search

1976-01-01

The installation of two fabrics, Petromat and Mirafi, to reduce reflection cracking on Route 17 in Gloucester County in- August 1976 is described. A brief review of the performance of previous installations is included. Finally, it is recommended tha...

16 CFR 660.2 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... reporting agency about an account or other relationship with the consumer correctly: (1) Reflects the terms of and liability for the account or other relationship; (2) Reflects the consumer's performance and other conduct with respect to the account or other relationship; and (3) Identifies the appropriate...

12 CFR 1022.41 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... reporting agency about an account or other relationship with the consumer correctly: (1) Reflects the terms of and liability for the account or other relationship; (2) Reflects the consumer's performance and other conduct with respect to the account or other relationship; and (3) Identifies the appropriate...

12 CFR 41.41 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... reporting agency about an account or other relationship with the consumer correctly: (1) Reflects the terms of and liability for the account or other relationship; (2) Reflects the consumer's performance and other conduct with respect to the account or other relationship; and (3) Identifies the appropriate...

12 CFR 571.41 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... reporting agency about an account or other relationship with the consumer correctly: (1) Reflects the terms of and liability for the account or other relationship; (2) Reflects the consumer's performance and other conduct with respect to the account or other relationship; and (3) Identifies the appropriate...

12 CFR 1022.41 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... reporting agency about an account or other relationship with the consumer correctly: (1) Reflects the terms of and liability for the account or other relationship; (2) Reflects the consumer's performance and other conduct with respect to the account or other relationship; and (3) Identifies the appropriate...

12 CFR 571.41 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... reporting agency about an account or other relationship with the consumer correctly: (1) Reflects the terms of and liability for the account or other relationship; (2) Reflects the consumer's performance and other conduct with respect to the account or other relationship; and (3) Identifies the appropriate...

12 CFR 571.41 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... reporting agency about an account or other relationship with the consumer correctly: (1) Reflects the terms of and liability for the account or other relationship; (2) Reflects the consumer's performance and other conduct with respect to the account or other relationship; and (3) Identifies the appropriate...

12 CFR 41.41 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... reporting agency about an account or other relationship with the consumer correctly: (1) Reflects the terms of and liability for the account or other relationship; (2) Reflects the consumer's performance and other conduct with respect to the account or other relationship; and (3) Identifies the appropriate...

12 CFR 41.41 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... reporting agency about an account or other relationship with the consumer correctly: (1) Reflects the terms of and liability for the account or other relationship; (2) Reflects the consumer's performance and other conduct with respect to the account or other relationship; and (3) Identifies the appropriate...

16 CFR 660.2 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... reporting agency about an account or other relationship with the consumer correctly: (1) Reflects the terms of and liability for the account or other relationship; (2) Reflects the consumer's performance and other conduct with respect to the account or other relationship; and (3) Identifies the appropriate...

16 CFR 660.2 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... reporting agency about an account or other relationship with the consumer correctly: (1) Reflects the terms of and liability for the account or other relationship; (2) Reflects the consumer's performance and other conduct with respect to the account or other relationship; and (3) Identifies the appropriate...

16 CFR 660.2 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... reporting agency about an account or other relationship with the consumer correctly: (1) Reflects the terms of and liability for the account or other relationship; (2) Reflects the consumer's performance and other conduct with respect to the account or other relationship; and (3) Identifies the appropriate...

12 CFR 571.41 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... reporting agency about an account or other relationship with the consumer correctly: (1) Reflects the terms of and liability for the account or other relationship; (2) Reflects the consumer's performance and other conduct with respect to the account or other relationship; and (3) Identifies the appropriate...

12 CFR 41.41 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... reporting agency about an account or other relationship with the consumer correctly: (1) Reflects the terms of and liability for the account or other relationship; (2) Reflects the consumer's performance and other conduct with respect to the account or other relationship; and (3) Identifies the appropriate...

12 CFR 1022.41 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... reporting agency about an account or other relationship with the consumer correctly: (1) Reflects the terms of and liability for the account or other relationship; (2) Reflects the consumer's performance and other conduct with respect to the account or other relationship; and (3) Identifies the appropriate...

High-efficiency polarization conversion phase gradient metasurface for wideband anomalous reflection

NASA Astrophysics Data System (ADS)

Zhang, Jiameng; Yang, Lan; Li, Linpeng; Zhang, Tong; Li, Haihong; Wang, Qingmin; Hao, Yanan; Lei, Ming; Bi, Ke

2017-07-01

An ultra-wideband polarization conversion metasurface based on S-shaped metallic structure is designed and prepared. The simulation results show that the polarization conversion bandwidth is 14 GHz for linearly polarized normally incident electromagnetic waves and the cross-polarized reflectance is more than 99% in the range of 10.3 GHz-20.5 GHz. On the premise of high reflection efficiency, the reflective phase can be regulated by changing the geometrical parameter of the S-shaped metallic structure. A phase gradient metasurface composed of six periodically arrayed S-shaped unit cells is proposed and further demonstrated both numerically and experimentally. The specular cross-polarization reflection of the phase gradient metasurface is below -10 dB, which shows a good performance on manipulating the direction of the reflected electromagnetic waves.

Generating Global Leaf Area Index from Landsat: Algorithm Formulation and Demonstration

NASA Technical Reports Server (NTRS)

Ganguly, Sangram; Nemani, Ramakrishna R.; Zhang, Gong; Hashimoto, Hirofumi; Milesi, Cristina; Michaelis, Andrew; Wang, Weile; Votava, Petr; Samanta, Arindam; Melton, Forrest;

The mediating effect of self-reflection and learning effectiveness on clinical nursing performance in nursing students: A follow-up study.

PubMed

Pai, Hsiang-Chu; Ko, Hui-Ling; Eng, Cheng-Joo; Yen, Wen-Jiuan

The effectiveness of simulation learning and the effects of anxiety in the simulated situation have been understudied. In addition, research on the association between learning effectiveness and students' clinical care performance in the hospital setting is very limited in Taiwan. The aim of this study is to examine the mediating effect of self-reflection and simulation learning effectiveness on the clinical nursing performance of nursing students. A Prospective, longitudinal, and correlational design was used. The study was conducted from December 2014 to July 2015. Participants were 293 nursing students in southern Taiwan. A structural model was specified and tested using partial least squares structural equation modeling to examine the relationships between the variables. The results revealed that the model was robust in terms of its measurement quality (reliability, validity, and goodness of fit), with the data's explaining 38.3% of variance in nursing competence. As self-reflection and learning effectiveness were added into the structural model, the effect of anxiety on nursing competence was still significant, but the regression coefficient (β) estimate of -0.41 (p<0.05) changed to β=-0.15 (p<0.050),indicating that self-reflection and learning effectiveness mediated the relationship between anxiety and nursing competence. Nursing competence was negatively affected by anxiety and positively affected by self-reflection (β=0.49, p<0.05) and simulation learning effectiveness (β=0.10, p<0.05). The teacher's encouraging learning can have a positive influence on students' self-reflection and learning effectiveness, which then decreases the effect of anxiety on nursing competence and further promotes students' clinical care ability. Copyright © 2017 Elsevier Inc. All rights reserved.

Properties of light reflected from road signs in active imaging for driving safety

NASA Astrophysics Data System (ADS)

Halstuch, Aviran; Yitzhaky, Yitzhak

2007-10-01

Night-vision systems in vehicles are a new emerging technology. A crucial problem in active (illumination-based) systems is distortion of images by saturation and blooming, due to strong retro-reflections from road signs. In this work we quantified this phenomenon. We measured the Mueller matrices and the polarization state of the reflected light from three different types of road signs commonly used. Measurements of the reflected intensity were taken also with respect to the angle of reflection. We found that different types of signs have different reflection properties. It is concluded from our measurements that the optimal solution for attenuating the retro-reflected intensity is using a linear horizontal polarized light source and a linear vertical polarizer. Unfortunately, while the performance of this solution is good for two types of road signs, it is less efficient for the third sign type.

Reflective Practice in the Clinical Setting: A Multi-Institutional Qualitative Study of Pediatric Faculty and Residents.

PubMed

Plant, Jennifer; Li, Su-Ting T; Blankenburg, Rebecca; Bogetz, Alyssa L; Long, Michele; Butani, Lavjay

2017-11-01

To explore when and in what form pediatric faculty and residents practice reflection. From February to June 2015, the authors conducted focus groups of pediatric faculty and residents at the University of California, Davis; Stanford University; and the University of California, San Francisco, until thematic saturation occurred. Transcripts were analyzed based on Mezirow's and Schon's models of reflection, using the constant comparative method associated with grounded theory. Two investigators independently coded transcripts and reconciled codes to develop themes. All investigators reviewed the codes and developed a final list of themes through consensus. Through iterative discussions, investigators developed a conceptual model of reflection in the clinical setting. Seventeen faculty and 20 residents from three institutions participated in six focus groups. Five themes emerged: triggers of reflection, intrinsic factors, extrinsic factors, timing, and outcome of reflection. Various triggers led to reflection; whether a specific trigger led to reflection depended on intrinsic and extrinsic factors. When reflection occurred, it happened in action or on action. Under optimal conditions, this reflection was goal and action directed and became critical reflection. In other instances, this process resulted in unproductive rumination or acted as an emotional release or supportive therapy. Participants reflected in clinical settings, but did not always explicitly identify it as reflection or reflect in growth-promoting ways. Strategies to enhance critical reflection include developing knowledge and skills in reflection, providing performance data to inform reflection, creating time and space for safe reflection, and providing mentorship to guide the process.

Dielectric compound parabolic concentrating solar collector with a frustrated total internal reflection absorber.

PubMed

Hull, J R

1989-01-01

Coupling a dielectric compound parabolic concentrator (DCPC) to an absorber across a vacuum gap by means of frustrated total internal reflection (FTIR) can theoretically approach the maximum concentration permitted by physical laws, thus allowing higher radiative fluxes in thermal applications. The calculated optical performance of 2-D DCPCs with FTIR absorbers indicates that the ratio of gap thickness to optical wavelength must be <0.22 before the optical performance of the DCPC is superior to that of the nondielectric CPC.

A Multi-Wavelength Thermal Infrared and Reflectance Scene Simulation Model

NASA Technical Reports Server (NTRS)

Ballard, J. R., Jr.; Smith, J. A.; Smith, David E. (Technical Monitor)

2002-01-01

Several theoretical calculations are presented and our approach discussed for simulating overall composite scene thermal infrared exitance and canopy bidirectional reflectance of a forest canopy. Calculations are performed for selected wavelength bands of the DOE Multispectral Thermal Imagery and comparisons with atmospherically corrected MTI imagery are underway. NASA EO-1 Hyperion observations also are available and the favorable comparison of our reflective model results with these data are reported elsewhere.

Telerobotic hand controller study of force reflection with position control mode

NASA Technical Reports Server (NTRS)

Willshire, Kelli F.; Hankins, Walter W.; Morris, A. Terry; Mixon, Randolph W.

1992-01-01

To gain further information about the effectiveness of kinesthetic force feedback or force reflection in position control mode for a telerobot, two Space Station related tasks were performed by eight subjects with and without the use of force reflection. Both time and subjective responses were measured. No differences due to force were found, however, other differences were found, e.g., gender. Comparisons of these results with other studies are discussed.

The Improved Dual-view Field Goniometer System FIGOS

PubMed Central

Schopfer, Jürg; Dangel, Stefan; Kneubühler, Mathias; Itten, Klaus I.

2008-01-01

In spectrodirectional Remote Sensing (RS) the Earth's surface reflectance characteristics are studied by means of their angular dimensions. Almost all natural surfaces exhibit an individual anisotropic reflectance behaviour due to the contrast between the optical properties of surface elements and background and the geometric surface properties of the observed scene. The underlying concept, which describes the reflectance characteristic of a specific surface area, is called the bidirectional reflectance distribution function (BRDF). BRDF knowledge is essential for both correction of directional effects in RS data and quantitative retrieval of surface parameters. Ground-based spectrodirectional measurements are usually performed with goniometer systems. An accurate retrieval of the bidirectional reflectance factors (BRF) from field goniometer measurements requires hyperspectral knowledge of the angular distribution of the reflected and the incident radiation. However, prior to the study at hand, no operational goniometer system was able to fulfill this requirement. This study presents the first dual-view field goniometer system, which is able to simultaneously collect both the reflected and the incident radiation at high angular and spectral resolution and, thus, providing the necessary spectrodirectional datasets to accurately retrieve the surface specific BRF. Furthermore, the angular distribution of the incoming diffuse radiation is characterized for various atmospheric conditions and the BRF retrieval is performed for an artificial target and compared to laboratory spectrodirectional measurement results obtained with the same goniometer system. Suggestions for further improving goniometer systems are given and the need for intercalibration of various goniometers as well as for standardizing spectrodirectional measurements is expressed. PMID:27873805

The Improved Dual-view Field Goniometer System FIGOS.

PubMed

Schopfer, Jürg; Dangel, Stefan; Kneubühler, Mathias; Itten, Klaus I

2008-08-28

In spectrodirectional Remote Sensing (RS) the Earth's surface reflectance characteristics are studied by means of their angular dimensions. Almost all natural surfaces exhibit an individual anisotropic reflectance behaviour due to the contrast between the optical properties of surface elements and background and the geometric surface properties of the observed scene. The underlying concept, which describes the reflectance characteristic of a specific surface area, is called the bidirectional reflectance distribution function (BRDF). BRDF knowledge is essential for both correction of directional effects in RS data and quantitative retrieval of surface parameters. Ground-based spectrodirectional measurements are usually performed with goniometer systems. An accurate retrieval of the bidirectional reflectance factors (BRF) from field goniometer measurements requires hyperspectral knowledge of the angular distribution of the reflected and the incident radiation. However, prior to the study at hand, no operational goniometer system was able to fulfill this requirement. This study presents the first dual-view field goniometer system, which is able to simultaneously collect both the reflected and the incident radiation at high angular and spectral resolution and, thus, providing the necessary spectrodirectional datasets to accurately retrieve the surface specific BRF. Furthermore, the angular distribution of the incoming diffuse radiation is characterized for various atmospheric conditions and the BRF retrieval is performed for an artificial target and compared to laboratory spectrodirectional measurement results obtained with the same goniometer system. Suggestions for further improving goniometer systems are given and the need for intercalibration of various goniometers as well as for standardizing spectrodirectional measurements is expressed.

Transportable and vibration-free full-field low-coherent quantitative phase microscope

NASA Astrophysics Data System (ADS)

Yamauchi, Toyohiko; Yamada, Hidenao; Goto, Kentaro; Matsui, Hisayuki; Yasuhiko, Osamu; Ueda, Yukio

2018-02-01

We developed a transportable Linnik-type full-field low-coherent quantitative phase microscope that is able to compensate for optical path length (OPL) disturbance due to environmental mechanical noises. Though two-beam interferometers such as Linnik ones suffer from unstable OPL difference, we overcame this problem with a mechanical feedback system based on digital signal-processing that controls the OPL difference in sub-nanometer resolution precisely with a feedback bandwidth of 4 kHz. The developed setup has a footprint of 200 mm by 200 mm, a height of 500 mm, and a weight of 4.5 kilograms. In the transmission imaging mode, cells were cultured on a reflection-enhanced glass-bottom dish, and we obtained interference images sequentially while performing stepwise quarter-wavelength phase-shifting. Real-time image processing, including retrieval of the unwrapped phase from interference images and its background correction, along with the acquisition of interference images, was performed on a laptop computer. Emulation of the phase contrast (PhC) images and the differential interference contrast (DIC) images was also performed in real time. Moreover, our setup was applied for full-field cell membrane imaging in the reflection mode, where the cells were cultured on an anti-reflection (AR)-coated glass-bottom dish. The phase and intensity of the light reflected by the membrane revealed the outer shape of the cells independent of the refractive index. In this paper, we show imaging results on cultured cells in both transmission and reflection modes.

Capturing Rehearsals to Facilitate Reflection

ERIC Educational Resources Information Center

Albayrak, Meltem; Smith, Brian K.

2004-01-01

Many learning environments involve rituals for rehearsal and reflection. Musicians, for instance, spend countless hours practicing scales and adjusting their bodies to increase their skills. But they do more than simply practice: They also play for instructors and others who can provide valuable critiques of their performances. Architectural…

12 CFR 717.41 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... provides to a consumer reporting agency about an account or other relationship with the consumer correctly: (1) Reflects the terms of and liability for the account or other relationship; (2) Reflects the consumer's performance and other conduct with respect to the account or other relationship; and (3...

12 CFR 717.41 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... provides to a consumer reporting agency about an account or other relationship with the consumer correctly: (1) Reflects the terms of and liability for the account or other relationship; (2) Reflects the consumer's performance and other conduct with respect to the account or other relationship; and (3...

12 CFR 717.41 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... provides to a consumer reporting agency about an account or other relationship with the consumer correctly: (1) Reflects the terms of and liability for the account or other relationship; (2) Reflects the consumer's performance and other conduct with respect to the account or other relationship; and (3...

12 CFR 222.41 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... relationship with the consumer correctly: (1) Reflects the terms of and liability for the account or other relationship; (2) Reflects the consumer's performance and other conduct with respect to the account or other relationship; and (3) Identifies the appropriate consumer. (b) Direct dispute means a dispute submitted...

12 CFR 222.41 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... relationship with the consumer correctly: (1) Reflects the terms of and liability for the account or other relationship; (2) Reflects the consumer's performance and other conduct with respect to the account or other relationship; and (3) Identifies the appropriate consumer. (b) Direct dispute means a dispute submitted...

12 CFR 334.41 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... furnisher provides to a consumer reporting agency about an account or other relationship with the consumer correctly: (1) Reflects the terms of and liability for the account or other relationship; (2) Reflects the consumer's performance and other conduct with respect to the account or other relationship; and (3...

12 CFR 334.41 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... furnisher provides to a consumer reporting agency about an account or other relationship with the consumer correctly: (1) Reflects the terms of and liability for the account or other relationship; (2) Reflects the consumer's performance and other conduct with respect to the account or other relationship; and (3...

12 CFR 334.41 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... furnisher provides to a consumer reporting agency about an account or other relationship with the consumer correctly: (1) Reflects the terms of and liability for the account or other relationship; (2) Reflects the consumer's performance and other conduct with respect to the account or other relationship; and (3...

12 CFR 334.41 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... furnisher provides to a consumer reporting agency about an account or other relationship with the consumer correctly: (1) Reflects the terms of and liability for the account or other relationship; (2) Reflects the consumer's performance and other conduct with respect to the account or other relationship; and (3...

12 CFR 717.41 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... provides to a consumer reporting agency about an account or other relationship with the consumer correctly: (1) Reflects the terms of and liability for the account or other relationship; (2) Reflects the consumer's performance and other conduct with respect to the account or other relationship; and (3...

Graders' Mathematics Achievement

ERIC Educational Resources Information Center

Bond, John B.; Ellis, Arthur K.

2013-01-01

The purpose of this experimental study was to investigate the effects of metacognitive reflective assessment instruction on student achievement in mathematics. The study compared the performance of 141 students who practiced reflective assessment strategies with students who did not. A posttest-only control group design was employed, and results…

Dew point measurement technique utilizing fiber cut reflection

NASA Astrophysics Data System (ADS)

Kostritskii, S. M.; Dikevich, A. A.; Korkishko, Yu. N.; Fedorov, V. A.

2009-05-01

The fiber optical dew point hygrometer based on change of reflection coefficient for fiber cut has been developed and examined. We proposed and verified the model of condensation detector functioning principle. Experimental frost point measurements on air with different frost points have been performed.

Freeze-Dried Carbon Nanotube Aerogels for High-Frequency Absorber Applications.

PubMed

Anoshkin, Ilya V; Campion, James; Lioubtchenko, Dmitri V; Oberhammer, Joachim

2018-06-13

A novel technique for millimeter wave absorber material embedded in a metal waveguide is proposed. The absorber material is a highly porous carbon nanotube (CNT) aerogel prepared by a freeze-drying technique. CNT aerogel structures are shown to be good absorbers with a low reflection coefficient, less than -12 dB at 95 GHz. The reflection coefficient of the novel absorber is 3-4 times lower than that of commercial absorbers with identical geometry. Samples prepared by freeze-drying at -25 °C demonstrate resonance behavior, while those prepared at liquid nitrogen temperature (-196 °C) exhibit a significant decrease in reflection coefficient, with no resonant behavior. CNT absorbers of identical volume based on wet-phase drying preparation show significantly worse performance than the CNT aerogel absorbers prepared by freeze-drying. Treatment of the freeze-dried CNT aerogel with n- and p-dopants (monoethanolamine and iodine vapors, respectively) shows remarkable improvement in the performance of the waveguide embedded absorbers, reducing the reflection coefficient by 2 dB across the band.

NASA ER-2 Doppler radar reflectivity calibration for the CAMEX project

NASA Technical Reports Server (NTRS)

Caylor, I. J.; Heymsfield, G. M.; Bidwell, S. W.; Ameen, S.

1994-01-01

The NASA ER-2 Doppler radar (EDOP) was flown aboard the ER-2 high-altitude aircraft in September and October 1993 for the Convection and Moisture Experiment. During these flights, the first reliable reflectivity observations were performed with the EDOP instrument. This report details the procedure used to convert real-time engineering data into calibrated radar reflectivity. Application of the calibration results produces good agreement between the EDOP nadir pointing reflectivity and ground truth provided by a National Weather Service WSR-88D radar. The rms deviation between WSR-88D and EDOP is 6.9 dB, while measurements of the ocean surface backscatter coefficient are less than 3 dB from reported scatterometer coefficients. After an initial 30-minute period required for the instrument to reach thermal equilibrium, the radar is stable to better than 0.25 dB during flight. The range performance of EDOP shows excellent agreement with aircraft altimeter and meteorological sounding data.

Depth rotation and mirror-image reflection reduce affective preference as well as recognition memory for pictures of novel objects.

PubMed

Lawson, Rebecca

2004-10-01

In two experiments, the identification of novel 3-D objects was worse for depth-rotated and mirror-reflected views, compared with the study view in an implicit affective preference memory task, as well as in an explicit recognition memory task. In Experiment 1, recognition was worse and preference was lower when depth-rotated views of an object were paired with an unstudied object relative to trials when the study view of that object was shown. There was a similar trend for mirror-reflected views. In Experiment 2, the study view of an object was both recognized and preferred above chance when it was paired with either depth-rotated or mirror-reflected views of that object. These results suggest that view-sensitive representations of objects mediate performance in implicit, as well as explicit, memory tasks. The findings do not support the claim that separate episodic and structural description representations underlie performance in implicit and explicit memory tasks, respectively.

Narrowband Angular Reflectance Properties of the Alkali Flats at White Sands, New Mexico

NASA Technical Reports Server (NTRS)

Whitlock, Charles H.; LeCroy, Stuart R.; Wheeler, Robert J.

1994-01-01

Results from helicopter measurements of the angular properties of surface reflectance for the alkali flats regions of the White Sands Missile Range are presented for the wavelength interval of 0.4 to 0.85 microns. This work was performed to allow accurate radiative transfer calculations over the region. Detailed tables and interpolation equations are given that permit other investigators to perform satellite calibrations over the alkali flats site. The effects of wavelength and soil moisture on narrowband angular reflectance are also investigated. Although there is a spectral variation in surface albedo, there is little spectral effect in Anisotropic Factor except in the forward scattering peak at solar zenith angles greater than 60 deg. The magnitude of the forward-scattering peak is also sensitive to soil moisture, with wet conditions causing a larger peak. The significance of this result is that angular reflectance properties at the center of the alkali flats usually will be different than those at the flats edge because moisture differences typically exist.

CRADA with United Solar Technologies and Pacific Northwest Laboratory (PNL-021): Thin film materialsfor low-cost high performance solar concentrators

NASA Astrophysics Data System (ADS)

Martin, P. M.; Affinito, J. D.; Gross, M. E.; Bennett, W. D.

1995-03-01

The objectives of this project were to develop and evaluate promising low-cost dielectric and polymer-protected thin-film reflective metal coatings to be applied to preformed continuously-curved solar reflector panels to enhance their solar reflectance, and to demonstrate protected solar reflective coatings on preformed solar concentrator panels. The opportunity for this project arose from a search by United Solar Technologies (UST) for organizations and facilities capable of applying reflective coatings to large preformed panels. PNL was identified as being uniquely qualified to participate in this collaborative project.

The size distribution of interstellar grains

NASA Technical Reports Server (NTRS)

Witt, Adolf N.

1987-01-01

Three major areas involving interstellar grains were investigated. First, studies were performed of scattering in reflection nebulae with the goal of deriving scattering characteristics of dust grains such as the albedo and the phase function asymmetry throughout the visible and the ultraviolet. Secondly, studies were performed of the wavelength dependence of interstellar extinction designed to demonstrate the wide range of grain size distributions naturally occurring in individual clouds in different parts of the galaxy. And thirdly, studies were also performed of the ultraviolet powered emission of dust grains in the 0.5 to 1.0 micron wavelength range in reflection nebulae. Findings considered of major importance are highlighted.

Sex and age-specific differences in ultraviolet reflectance of scent marks of bank voles (Clethrionomys glareolus).

PubMed

Koivula, M; Koskela, E; Viitala, J

1999-12-01

Scent markings of voles are visible via their ultraviolet reflection. Kestrels, and possibly other diurnal raptors, may use this property when hunting. We performed a laboratory study on bank voles to determine whether UV-reflectance of scent marks differs in relation to sex, age and social status. When reflectance spectra of scent marks were measured with a spectro-radiometer, we found UV reflectance to be strongest in mature males. There were no differences between mature females and immature juveniles, nor between sexes in juveniles or mature and immature individuals in females. Moreover, we did not find any difference in UV reflectance between dominant and subordinate mature males. The results of this study support earlier findings that UV sensitive predators may use UV reflectance of scent marks as a prey cue. Consequently, studies on differing vulnerability of voles to avian predators should take into account not only their space use and behaviour but also the UV reflectance of their scent marks.

Hyperspectral material identification on radiance data using single-atmosphere or multiple-atmosphere modeling

NASA Astrophysics Data System (ADS)

Mariano, Adrian V.; Grossmann, John M.

2010-11-01

Reflectance-domain methods convert hyperspectral data from radiance to reflectance using an atmospheric compensation model. Material detection and identification are performed by comparing the compensated data to target reflectance spectra. We introduce two radiance-domain approaches, Single atmosphere Adaptive Cosine Estimator (SACE) and Multiple atmosphere ACE (MACE) in which the target reflectance spectra are instead converted into sensor-reaching radiance using physics-based models. For SACE, known illumination and atmospheric conditions are incorporated in a single atmospheric model. For MACE the conditions are unknown so the algorithm uses many atmospheric models to cover the range of environmental variability, and it approximates the result using a subspace model. This approach is sometimes called the invariant method, and requires the choice of a subspace dimension for the model. We compare these two radiance-domain approaches to a Reflectance-domain ACE (RACE) approach on a HYDICE image featuring concealed materials. All three algorithms use the ACE detector, and all three techniques are able to detect most of the hidden materials in the imagery. For MACE we observe a strong dependence on the choice of the material subspace dimension. Increasing this value can lead to a decline in performance.

Identifiable Images of Bystanders Extracted from Corneal Reflections

PubMed Central

Jenkins, Rob; Kerr, Christie

2013-01-01

Criminal investigations often use photographic evidence to identify suspects. Here we combined robust face perception and high-resolution photography to mine face photographs for hidden information. By zooming in on high-resolution face photographs, we were able to recover images of unseen bystanders from reflections in the subjects' eyes. To establish whether these bystanders could be identified from the reflection images, we presented them as stimuli in a face matching task (Experiment 1). Accuracy in the face matching task was well above chance (50%), despite the unpromising source of the stimuli. Participants who were unfamiliar with the bystanders' faces (n = 16) performed at 71% accuracy [t(15) = 7.64, p<.0001, d = 1.91], and participants who were familiar with the faces (n = 16) performed at 84% accuracy [t(15) = 11.15, p<.0001, d = 2.79]. In a test of spontaneous recognition (Experiment 2), observers could reliably name a familiar face from an eye reflection image. For crimes in which the victims are photographed (e.g., hostage taking, child sex abuse), reflections in the eyes of the photographic subject could help to identify perpetrators. PMID:24386177

Comparative Analysis of Aerosol Retrievals from MODIS, OMI and MISR Over Sahara Region

NASA Technical Reports Server (NTRS)

Lyapustin, A.; Wang, Y.; Hsu, C.; Terres, O.; Leptoukh, G.; Kalashnikova, O.; Korkin, S.

2011-01-01

MODIS is a wide field-of-view sensor providing daily global observations of the Earth. Currently, global MODIS aerosol retrievals over land are performed with the main Dark Target algorithm complimented with the Deep Blue (DB) Algorithm over bright deserts. The Dark Target algorithm relies on surface parameterization which relates reflectance in MODIS visible bands with the 2.1 micrometer region, whereas the Deep Blue algorithm uses an ancillary angular distribution model of surface reflectance developed from the time series of clear-sky MODIS observations. Recently, a new Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm has been developed for MODIS. MAIAC uses a time series and an image based processing to perform simultaneous retrievals of aerosol properties and surface bidirectional reflectance. It is a generic algorithm which works over both dark vegetative surfaces and bright deserts and performs retrievals at 1 km resolution. In this work, we will provide a comparative analysis of DB, MAIAC, MISR and OMI aerosol products over bright deserts of northern Africa.

Test Framing Generates a Stability Bias for Predictions of Learning by Causing People to Discount their Learning Beliefs

PubMed Central

Ariel, Robert; Hines, Jarrod C.; Hertzog, Christopher

2014-01-01

People estimate minimal changes in learning when making predictions of learning (POLs) for future study opportunities despite later showing increased performance and an awareness of that increase (Kornell & Bjork, 2009). This phenomenon is conceptualized as a stability bias in judgments about learning. We investigated the malleability of this effect, and whether it reflected people’s underlying beliefs about learning. We manipulated prediction framing to emphasize the role of testing vs. studying on memory and directly measured beliefs about multi-trial study effects on learning by having participants construct predicted learning curves before and after the experiment. Mean POLs were more sensitive to the number of study-test opportunities when performance was framed in terms of study benefits rather than testing benefits and POLs reflected pre-existing beliefs about learning. The stability bias is partially due to framing and reflects discounted beliefs about learning benefits rather than inherent belief in the stability of performance. PMID:25067885

Test Framing Generates a Stability Bias for Predictions of Learning by Causing People to Discount their Learning Beliefs.

PubMed

Ariel, Robert; Hines, Jarrod C; Hertzog, Christopher

2014-08-01

People estimate minimal changes in learning when making predictions of learning (POLs) for future study opportunities despite later showing increased performance and an awareness of that increase (Kornell & Bjork, 2009). This phenomenon is conceptualized as a stability bias in judgments about learning. We investigated the malleability of this effect, and whether it reflected people's underlying beliefs about learning. We manipulated prediction framing to emphasize the role of testing vs. studying on memory and directly measured beliefs about multi-trial study effects on learning by having participants construct predicted learning curves before and after the experiment. Mean POLs were more sensitive to the number of study-test opportunities when performance was framed in terms of study benefits rather than testing benefits and POLs reflected pre-existing beliefs about learning. The stability bias is partially due to framing and reflects discounted beliefs about learning benefits rather than inherent belief in the stability of performance.

The Difference Between Countermovement and Squat Jump Performances: A Review of Underlying Mechanisms With Practical Applications.

PubMed

Van Hooren, Bas; Zolotarjova, Julia

2017-07-01

Van Hooren, B and Zolotarjova, J. The difference between countermovement and squat jump performances: a review of underlying mechanisms with practical applications. J Strength Cond Res 31(7): 2011-2020, 2017-Two movements that are widely used to monitor athletic performance are the countermovement jump (CMJ) and squat jump (SJ). Countermovement jump performance is almost always better than SJ performance, and the difference in performance is thought to reflect an effective utilization of the stretch-shortening cycle. However, the mechanisms responsible for the performance-enhancing effect of the stretch-shortening cycle are frequently undefined. Uncovering and understanding these mechanisms is essential to make an inference regarding the difference between the jumps. Therefore, we will review the potential mechanisms that explain the better performance in a CMJ as compared with a SJ. It is concluded that the difference in performance may primarily be related to the greater uptake of muscle slack and the buildup of stimulation during the countermovement in a CMJ. Elastic energy may also have a small contribution to an enhanced CMJ performance. Therefore, a larger difference between the jumps is not necessarily a better indicator of high-intensity sports performance. Although a larger difference may reflect the utilization of elastic energy in a small-amplitude CMJ as a result of a well-developed capability to co-activate muscles and quickly build up stimulation, a larger difference may also reflect a poor capability to reduce the degree of muscle slack and build up stimulation in the SJ. Because the capability to reduce the degree of muscle slack and quickly build up stimulation in the SJ may be especially important to high-intensity sports performance, training protocols might concentrate on attaining a smaller difference between the jumps.

Evaluation of emergency department performance – a systematic review on recommended performance and quality-in-care measures

PubMed Central

2013-01-01

Background Evaluation of emergency department (ED) performance remains a difficult task due to the lack of consensus on performance measures that reflects high quality, efficiency, and sustainability. Aim To describe, map, and critically evaluate which performance measures that the published literature regard as being most relevant in assessing overall ED performance. Methods Following the PRISMA guidelines, a systematic literature review of review articles reporting accentuated ED performance measures was conducted in the databases of PubMed, Cochrane Library, and Web of Science. Study eligibility criteria includes: 1) the main purpose was to discuss, analyse, or promote performance measures best reflecting ED performance, 2) the article was a review article, and 3) the article reported macro-level performance measures, thus reflecting an overall departmental performance level. Results A number of articles addresses this study’s objective (n = 14 of 46 unique hits). Time intervals and patient-related measures were dominant in the identified performance measures in review articles from US, UK, Sweden and Canada. Length of stay (LOS), time between patient arrival to initial clinical assessment, and time between patient arrivals to admission were highlighted by the majority of articles. Concurrently, “patients left without being seen” (LWBS), unplanned re-attendance within a maximum of 72 hours, mortality/morbidity, and number of unintended incidents were the most highlighted performance measures that related directly to the patient. Performance measures related to employees were only stated in two of the 14 included articles. Conclusions A total of 55 ED performance measures were identified. ED time intervals were the most recommended performance measures followed by patient centeredness and safety performance measures. ED employee related performance measures were rarely mentioned in the investigated literature. The study’s results allow for advancement towards improved performance measurement and standardised assessment across EDs. PMID:23938117

Design and Construction of a Field Capable Snapshot Hyperspectral Imaging Spectrometer

NASA Technical Reports Server (NTRS)

Arik, Glenda H.

2005-01-01

The computed-tomography imaging spectrometer (CTIS) is a device which captures the spatial and spectral content of a rapidly evolving same in a single image frame. The most recent CTIS design is optically all reflective and uses as its dispersive device a stated the-art reflective computer generated hologram (CGH). This project focuses on the instrument's transition from laboratory to field. This design will enable the CTIS to withstand a harsh desert environment. The system is modeled in optical design software using a tolerance analysis. The tolerances guide the design of the athermal mount and component parts. The parts are assembled into a working mount shell where the performance of the mounts is tested for thermal integrity. An interferometric analysis of the reflective CGH is also performed.

Fully reflective deep ultraviolet to near infrared spectrometer and entrance optics for resonance Raman spectroscopy

NASA Astrophysics Data System (ADS)

Schulz, B.; Bäckström, J.; Budelmann, D.; Maeser, R.; Rübhausen, M.; Klein, M. V.; Schoeffel, E.; Mihill, A.; Yoon, S.

2005-07-01

We present the design and performance of a new triple-grating deep ultraviolet to near-infrared spectrometer. The system is fully achromatic due to the use of reflective optics. The minimization of image aberrations by using on- and off- axis parabolic mirrors as well as elliptical mirrors yields a strong stray light rejection with high resolution over a wavelength range between 165 and 1000nm. The Raman signal is collected with a reflective entrance objective with a numerical aperture of 0.5, featuring a Cassegrain-type design. Resonance Raman studies on semiconductors and on correlated compounds, such as LaMnO3, highlight the performance of this instrument, and show diverse resonance effects between 1.96 and 5.4eV.

Application of a reflective microscope objective for multiphoton microscopy.

PubMed

Kabir, Mohammad M; Choubal, Aakash M; Toussaint, Kimani C

2018-04-20

Reflective objectives (ROs) mitigate chromatic aberration across a broad wavelength range. Yet, a systematic performance characterisation of ROs has not been done. In this paper, we compare the performance of a 0.5 numerical-aperture (NA) reflective objective (RO) with a 0.55 NA standard glass objective (SO), using two-photon fluorescence (TPF) and second-harmonic generation (SHG). For experiments spanning ∼1 octave in the visible and NIR wavelengths, the SO leads to defocusing errors of 25-40% for TPF images of subdiffraction fluorescent beads and 10-12% for SHG images of collagen fibres. The corresponding error for the RO is ∼4% for both imaging modalities. This work emphasises the potential utility of ROs for multimodal multiphoton microscopy applications. © 2018 The Authors Journal of Microscopy © 2018 Royal Microscopical Society.

Process of preparing metal parts to be heated by means of infrared radiance

DOEpatents

Mayer, Howard Robinson [Cincinnati, OH; Blue, Craig A [Knoxville, TN

2009-06-09

A method for preparing metal for heating by infrared radiance to enable uniform and consistent heating. The surface of one or more metal parts, such as aluminum or aluminum alloy parts, is treated to alter the surface finish to affect the reflectivity of the surface. The surface reflectivity is evaluated, such as by taking measurements at one or more points on the surface, to determine if a desired reflectivity has been achieved. The treating and measuring are performed until the measuring indicates that the desired reflectivity has been achieved. Once the treating has altered the surface finish to achieve the desired reflectivity, the metal part may then be exposed to infrared radiance to heat the metal part to a desired temperature, and that heating will be substantially consistent throughout by virtue of the desired reflectivity.

Analysis for Mar Vel Black and acetylene soot low reflectivity surfaces for star tracker sunshade applications

NASA Technical Reports Server (NTRS)

Yung, E.

1974-01-01

Mar Vel Black is a revolutionary new extremely low reflectivity anodized coating developed by Martin Marietta of Denver. It is of great interest in optics in general, and in star trackers specifically because it can reduce extraneous light reflections. A sample of Mar Vel Black was evaluated. Mar Vel Black looks much like a super black surface with many small peaks and very steep sides so that any light incident upon the surface will tend to reflect many times before exiting that surface. Even a high reflectivity surface would thus appear to have a very low reflectivity under such conditions. Conversely, acetylene soot does not have the magnified surface appearance of a super black surface. Its performance is, however, predictable from the surface structure, considering the known configuration of virtually pure carbon.

Self-reflection modulates the outcome evaluation process: Evidence from an ERP study.

PubMed

Zhu, Xiangru; Gu, Ruolei; Wu, Haiyan; Luo, Yuejia

2015-12-01

Recent research demonstrated structural overlap between reward and self processing, but the functional relationship that explains how self processing influences reward processing remains unclear. The present study used an experimentally constrained reflection task to investigate whether individuals' outcome evaluations in a gambling task are modulated by task-unrelated self- and other-reflection processes. The self- and other-reflection task contained descriptions of the self or others, and brain event-related potentials (ERPs) were recorded while 16 normal adults performed a gambling task. The ERP analysis focused on the feedback-related negativity (FRN) component. We found that the difference wave of FRN increased in the self-reflection condition compared with the other-reflection condition. The present findings provide direct evidence that self processing can influence reward processing. Copyright © 2015 Elsevier B.V. All rights reserved.

Sensor Performance Requirements for the Retrieval of Atmospheric Aerosols by Airborne Optical Remote Sensing

PubMed Central

Seidel, Felix; Schläpfer, Daniel; Nieke, Jens; Itten, Klaus I.

2008-01-01

This study explores performance requirements for the retrieval of the atmospheric aerosol optical depth (AOD) by airborne optical remote sensing instruments. Independent of any retrieval techniques, the calculated AOD retrieval requirements are compared with the expected performance parameters of the upcoming hyperspectral sensor APEX at the reference wavelength of 550nm. The AOD accuracy requirements are defined to be capable of resolving transmittance differences of 0.01 to 0.04 according to the demands of atmospheric corrections for remote sensing applications. For the purposes of this analysis, the signal at the sensor level is simulated by radiation transfer equations. The resulting radiances are translated into the AOD retrieval sensitivity (Δτλaer) and compared to the available measuring sensitivity of the sensor (NEΔLλsensor). This is done for multiple signal-to-noise ratios (SNR) and surface reflectance values. It is shown that an SNR of 100 is adequate for AOD retrieval at 550nm under typical remote sensing conditions and a surface reflectance of 10% or less. Such dark surfaces require the lowest SNR values and therefore offer the best sensitivity for measuring AOD. Brighter surfaces with up to 30% reflectance require an SNR of around 300. It is shown that AOD retrieval for targets above 50% surface reflectance is more problematic with the current sensor performance as it may require an SNR larger than 1000. In general, feasibility is proven for the analyzed cases under simulated conditions. PMID:27879801

Sensor Performance Requirements for the Retrieval of Atmospheric Aerosols by Airborne Optical Remote Sensing.

PubMed

Seidel, Felix; Schläpfer, Daniel; Nieke, Jens; Itten, Klaus I

2008-03-18

This study explores performance requirements for the retrieval of the atmospheric aerosol optical depth (AOD) by airborne optical remote sensing instruments. Independent of any retrieval techniques, the calculated AOD retrieval requirements are compared with the expected performance parameters of the upcoming hyperspectral sensor APEX at the reference wavelength of 550nm. The AOD accuracy requirements are defined to be capable of resolving transmittance differences of 0.01 to 0.04 according to the demands of atmospheric corrections for remote sensing applications. For the purposes of this analysis, the signal at the sensor level is simulated by radiation transfer equations. The resulting radiances are translated into the AOD retrieval sensitivity (Δτ λ aer ) and compared to the available measuring sensitivity of the sensor (NE ΔL λ sensor ). This is done for multiple signal-to-noise ratios (SNR) and surface reflectance values. It is shown that an SNR of 100 is adequate for AOD retrieval at 550nm under typical remote sensing conditions and a surface reflectance of 10% or less. Such dark surfaces require the lowest SNR values and therefore offer the best sensitivity for measuring AOD. Brighter surfaces with up to 30% reflectance require an SNR of around 300. It is shown that AOD retrieval for targets above 50% surface reflectance is more problematic with the current sensor performance as it may require an SNR larger than 1000. In general, feasibility is proven for the analyzed cases under simulated conditions.

High-Reflectivity Coatings for a Vacuum Ultraviolet Spectropolarimeter

NASA Astrophysics Data System (ADS)

Narukage, Noriyuki; Kubo, Masahito; Ishikawa, Ryohko; Ishikawa, Shin-nosuke; Katsukawa, Yukio; Kobiki, Toshihiko; Giono, Gabriel; Kano, Ryouhei; Bando, Takamasa; Tsuneta, Saku; Auchère, Frédéric; Kobayashi, Ken; Winebarger, Amy; McCandless, Jim; Chen, Jianrong; Choi, Joanne

2017-03-01

Precise polarization measurements in the vacuum ultraviolet (VUV) region are expected to be a new tool for inferring the magnetic fields in the upper atmosphere of the Sun. High-reflectivity coatings are key elements to achieving high-throughput optics for precise polarization measurements. We fabricated three types of high-reflectivity coatings for a solar spectropolarimeter in the hydrogen Lyman-α (Lyα; 121.567 nm) region and evaluated their performance. The first high-reflectivity mirror coating offers a reflectivity of more than 80 % in Lyα optics. The second is a reflective narrow-band filter coating that has a peak reflectivity of 57 % in Lyα, whereas its reflectivity in the visible light range is lower than 1/10 of the peak reflectivity (˜ 5 % on average). This coating can be used to easily realize a visible light rejection system, which is indispensable for a solar telescope, while maintaining high throughput in the Lyα line. The third is a high-efficiency reflective polarizing coating that almost exclusively reflects an s-polarized beam at its Brewster angle of 68° with a reflectivity of 55 %. This coating achieves both high polarizing power and high throughput. These coatings contributed to the high-throughput solar VUV spectropolarimeter called the Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP), which was launched on 3 September, 2015.

Acoustic analog computing based on a reflective metasurface with decoupled modulation of phase and amplitude

NASA Astrophysics Data System (ADS)

Zuo, Shu-Yu; Tian, Ye; Wei, Qi; Cheng, Ying; Liu, Xiao-Jun

2018-03-01

The use of metasurfaces has allowed the provision of a variety of functionalities by ultrathin structures, paving the way toward novel highly compact analog computing devices. Here, we conceptually realize analog computing using an acoustic reflective computational metasurface (RCM) that can independently manipulate the reflection phase and amplitude of an incident acoustic signal. This RCM is composed of coating unit cells and perforated panels, where the first can tune the transmission phase within the full range of 2π and the second can adjust the reflection amplitude in the range of 0-1. We show that this RCM can achieve arbitrary reflection phase and amplitude and can be used to realize a unique linear spatially invariant transfer function. Using the spatial Fourier transform (FT), an acoustic analog computing (AAC) system is proposed based on the RCM together with a focusing lens. Based on numerical simulations, we demonstrate that this AAC system can perform mathematical operations such as spatial differentiation, integration, and convolution on an incident acoustic signal. The proposed system has low complexity and reduced size because the RCM is able to individually adjust the reflection phase and amplitude and because only one block is involved in performing the spatial FT. Our work may offer a practical, efficient, and flexible approach to the design of compact devices for acoustic computing applications, signal processing, equation solving, and acoustic wave manipulations.

An experimental study of the reflection from spherical and flat ended cylindrical targets suitable for fetal Doppler performance assessment.

PubMed

Preston, R C; Bond, A D

1997-01-01

The performance of small-diameter targets suitable for use as oscillating targets for testing the sensitivity of Doppler fetal heartbeat detectors has been systematically studied. Experimental results are presented in the 1.6-3.0 MHz frequency range for the plane-wave reflection loss for a total of 16 targets: spherical balls made of stainless steel; hemispherical-ended rods made of PTFE; and flat-ended rods made of stainless steel, PTFE, polycarbonate, and tungsten carbide. Results show that the fine-structure variation of reflection loss with frequency is greatest in the case of spherical ball targets and least for flat-ended targets. It has been shown that, providing care is taken during manufacture, the reflection loss from a flat-ended target can be predicted using a simple theory based on a plane disc reflector. Tungsten carbide targets consisting of a long rod with a diameter of 1.6 mm tapered down to a cylindrical flat end with a diameter of 0.4, 0.5, and 0.6 mm have been shown to provide reflection losses of between 60 and 40 dB, and to have a smooth variation of reflection loss with frequency. They can also be manufactured in a form that allows no significant interference from the supporting structure and, therefore, are ideal targets to meet the requirements of International Electrotechnical Commission 1266:1995.

The variability puzzle in human memory.

PubMed

Kahana, Michael J; Aggarwal, Eash V; Phan, Tung D

2018-04-26

Memory performance exhibits a high level of variability from moment to moment. Much of this variability may reflect inadequately controlled experimental variables, such as word memorability, past practice and subject fatigue. Alternatively, stochastic variability in performance may largely reflect the efficiency of endogenous neural processes that govern memory function. To help adjudicate between these competing views, the authors conducted a multisession study in which subjects completed 552 trials of a delayed free-recall task. Applying a statistical model to predict variability in each subject's recall performance uncovered modest effects of word memorability, proactive interference, and other variables. In contrast to the limited explanatory power of these experimental variables, performance on the prior list strongly predicted current list recall. These findings suggest that endogenous factors underlying successful encoding and retrieval drive variability in performance. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Modeling the effect of reflection from metallic walls on spectroscopic measurements.

PubMed

Zastrow, K-D; Keatings, S R; Marot, L; O'Mullane, M G; de Temmerman, G

2008-10-01

A modification of JET is presently being prepared to bring operational experience with ITER-like first wall (Be) and divertor (W) materials, geometry and plasma parameters. Reflectivity measurements of JET sample tiles have been performed and the data are used within a simplified model of the JET and ITER vessels to predict additional contributions to quantitative spectroscopic measurements. The most general method to characterize reflectivity is the bidirectional reflection distribution function (BRDF). For extended sources however, such as bremsstrahlung and edge emission of fuel and intrinsic impurities, the results obtained in the modeling are almost as accurate if the total reflectivity with ideal Lambertian angular dependence is used. This is in contrast to the experience in other communities, such as optical design, lighting design, or rendering who deal mostly with pointlike light sources. This result is so far based on a very limited set of measurements and will be reassessed when more detailed BRDF measurements of JET tiles have been made. If it is true it offers the possibility of in situ monitoring of the reflectivity of selected parts of the wall during exposure to plasma operation, while remeasurement of the BRDF is performed during interventions. For a closed vessel structure such as ITER, it is important to consider multiple reflections. This makes it more important to represent the whole of the vessel reasonably accurately in the model, which on the other hand is easier to achieve than for the more complex internal structure of JET. In both cases the dominant contribution is from the first reflection, and a detailed model of the areas intersected by lines of sight of diagnostic interest is required.

Is subjective memory specific for memory performance or general across cognitive domains? Findings from the Seattle Longitudinal Study.

PubMed

Hülür, Gizem; Willis, Sherry L; Hertzog, Christopher; Schaie, K Warner; Gerstorf, Denis

2018-05-01

A growing body of research has examined whether people's judgments of their own memory functioning accurately reflect their memory performance at cross-section and over time. Relatively less is known about whether these judgments are specifically based on memory performance, or reflect general cognitive change. The aim of the present study was to examine longitudinal associations of subjective memory with performance in tests of episodic memory and a wide range of other cognitive tests, including the Wechsler Adult Intelligence Scale-Revised (WAIS-R) Block Design, Comprehension, Digit Span, Digit Symbol, and Vocabulary subtests. We applied latent growth curve models to five occasions over up to 16 years of neuropsychological assessments from 956 participants of the Seattle Longitudinal Study (SLS; 57% women; age at baseline: M = 65.1, SD = 11.4, 38 - 96 years). Results revealed that lower self-reported Frequency of Forgetting was significantly associated with better performance in all cognitive domains at baseline. The baseline correlation of Frequency of Forgetting with memory performance was stronger than its correlations with performance in other cognitive tests. Furthermore, additional analyses with baseline data showed that a latent memory performance factor reliably predicted Frequency of Forgetting after controlling for a general cognitive factor. Over time, steeper increases in Frequency of Forgetting were associated with steeper declines in tests of memory performance and in the Block Design and Digit Symbol subtests. Taken together, these findings suggest that although self-reported Frequency of Forgetting reflects performance in a broad range of other cognitive domains, it also shows some specificity for memory performance. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Fusing corn nitrogen recommendation tools for an improved canopy reflectance sensor performance

USDA-ARS?s Scientific Manuscript database

Nitrogen (N) rate recommendation tools are utilized to help producers maximize corn grain yield production. Many of these tools provide recommendations at field scales but often fail when corn N requirements are variable across the field. Canopy reflectance sensors are capable of capturing within-fi...

Improving the performance of active-optical reflectance sensor algorithms using soil and weather information

USDA-ARS?s Scientific Manuscript database

Active-optical reflectance sensors (AORS) use corn (Zea mays L.) plant tissue as a bioassay of crop N status to determine future N requirements. However, studies have shown AORS algorithms used for making N fertilizer recommendations are not consistently accurate. Thus, AORS algorithm improvements s...

Cost-effectiveness and performance of overlay systems in Illinois, volume 1 : effectiveness assessment of HMA overlay interlayer systems used to retard reflective cracking.

DOT National Transportation Integrated Search

2009-05-01

This project evaluated the ability of interlayer systems used in HMA overlays to retard reflective cracking. Field : crack surveys and forensic investigation, including video imaging and ground penetrating radar surveys as well : as laboratory testin...

Cost-effectiveness and performance of overlay systems in Illinois, volume 2 : guidelines for interlayer system selection decision when used in HMA overlays.

DOT National Transportation Integrated Search

2009-05-01

In an effort to control reflective cracking in hot-mix asphalt (HMA) overlays placed over Portland Cement : Concrete (PCC) pavements, several reflective crack control (RCC) systems, including interlayer systems, : have been used. However, the cost-ef...

Test/QA Plan for Verification of Semi-Continuous Ambient Air Monitoring Systems - Second Round

EPA Science Inventory

Test/QA Plan for Verification of Semi-Continuous Ambient Air Monitoring Systems - Second Round. Changes reflect performance of second round of testing at new location and with various changes to personnel. Additional changes reflect general improvements to the Version 1 test/QA...

Density-independent algorithm for sensing moisture content of sawdust based on reflection measurements

USDA-ARS?s Scientific Manuscript database

A density-independent algorithm for moisture content determination in sawdust, based on a one-port reflection measurement technique is proposed for the first time. Performance of this algorithm is demonstrated through measurement of the dielectric properties of sawdust with an open-ended haft-mode s...

Synthesis of National and International Methodologies Used for Bridge Health Indices

DOT National Transportation Integrated Search

2016-05-01

Bridge performance measures are important components of any successful Bridge Management System. Different types of performance measures have been developed for various purposes. The types of performance measures are usually a reflection of an agency...

5 CFR 430.404 - Certification criteria.

Code of Federal Regulations, 2011 CFR

2011-01-01

... responsibility; reflect expected agency and/or organizational outcomes and outputs, performance targets or... 430.404 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PERFORMANCE MANAGEMENT Performance Appraisal Certification for Pay Purposes § 430.404 Certification criteria. (a) To be...

A protocol for EBT3 radiochromic film dosimetry using reflection scanning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Papaconstadopoulos, Pavlos, E-mail: pavpapac@gmail.com; Hegyi, Gyorgy; Seuntjens, Jan

2014-12-15

Purpose: To evaluate the performance of the EBT3 radiochromic film dosimetry system using reflection measurements and to suggest a calibration protocol for precise and accurate reflection film dosimetry. Methods: A set of 14 Gafchromic EBT3 film pieces were irradiated to various doses ranging from 0 to 8 Gy and subsequently scanned using both the reflection and transmission mode. Scanning resolution varied from 50 to 508 dpi (0.5–0.05 mm/pixel). Both the red and green color channels of scanned images were used to relate the film response to the dose. A sensitivity, uncertainty, and accuracy analysis was performed for all scanning modesmore » and color channels. The total uncertainty, along with the fitting and experimental uncertainty components, was identified and analyzed. A microscope resolution target was used to evaluate possible resolution losses under reflection scanning. The calibration range was optimized for reflection scanning in the low (<2 Gy) and high (>2 Gy) dose regions based on the reported results. Results: Reflection scanning using the red channel exhibited the highest sensitivity among all modes, being up to 150% higher than transmission mode in the red channel for the lowest dose level. Furthermore, there was no apparent loss in resolution between the two modes. However, higher uncertainties and reduced accuracy were observed for the red channel under reflection mode, especially at dose levels higher than 2 Gy. These uncertainties were mainly attributed to saturation effects which were translated in poor fitting results. By restricting the calibration to the 0–2 Gy dose range, the situation is reversed and the red reflection mode was superior to the transmission mode. For higher doses, the green channel in reflection mode presented comparable results to the red transmission. Conclusions: A two-color reflection scanning protocol can be suggested for EBT3 radiochromic film dosimetry using the red channel for doses less than 2 Gy and the green channel for higher doses. The precision and accuracy are significantly improved in the low dose region following such a protocol.« less

An integrated model for the effects of self-reflection and clinical experiential learning on clinical nursing performance in nursing students: A longitudinal study.

PubMed

Pai, Hsiang-Chu

2016-10-01

The use of clinical simulation in undergraduate nursing programs in Taiwan has gradually increased over the past 5years. Previous research has shown that students' experience of anxiety during simulated laboratory sessions influences their self-reflection and learning effectiveness. Thus, further study that tracks what influences students' clinical performance in actual clinical sites is vital. The aim of the study is to develop an integrated model that considers the associations among anxiety, self-reflection, and learning effectiveness and to understand how this model applies to student nurses' clinical performance while on clinical placement. This study used a correlational and longitudinal study design. The 80 nursing students, who ranged in age from 19 to 21 (mean=20.38, SD=0.56), were recruited from a nursing school in southern Taiwan. Data were collected during three phases of implementation using four questionnaires. During the first phase, the State-Trait Anxiety Inventory (STAI), Simulation Learning Effectiveness Scale (SLES), and Self-Reflection and Insight Scale (SRIS) were used after students completed the simulation course in the school simulation laboratory. Nursing students also completed the Holistic Nursing Competence Scale at 2months (Phase 2) and 4months (Phase 3) after clinical practice experience. In Phase 3, students again completed the STAI and SRIS. Partial least squares (PLS), a structural equation modeling (SEM) procedure, was used to test the research model. The findings showed that: (1) at the start of the simulation laboratory, anxiety had a significant negative effect on students' simulation learning effectiveness (SLE; β=-0.14, p<0.05) and on self-reflection with insight (SRI; β=-0.52, p<0.01). Self-reflection also had a significant positive effect on simulation learning effectiveness (β=0.37, p<0.01). Anxiety had a significant negative effect on students' nursing competence during the first 2months of practice in a clinical nursing site (β=-0.20, p<0.01). Simulation learning effectiveness and self-reflection and insight also had a significant positive effect on nursing competence during the first 2months of practice in a clinical site (β=0.13; β=0.16, p<0.05), respectively; and (2) when students practice in a clinical setting, their previous experience of nursing competence during the first 2months of clinical care and their self-reflection and insight have a significant positive effect on their 4-month nursing competence (β=0.58; β=0.27, p<0.01). Anxiety, however, had a negative effect on 4-month nursing competence but not significantly. Overall, 41% of the variance in clinical nursing performance was accounted for by the variables in the integrated model. This study highlights that self-reflection with insight and clinical experience may help students to deflect anxiety that may influence the development of clinical competence. Of note is that real-life clinical experience has a stronger effect on enhancing clinical performance than does a simulation experience. Copyright © 2016 Elsevier Ltd. All rights reserved.

Investigation on the reproduction performance versus acoustic contrast control in sound field synthesis.

PubMed

Bai, Mingsian R; Wen, Jheng-Ciang; Hsu, Hoshen; Hua, Yi-Hsin; Hsieh, Yu-Hao

2014-10-01

A sound reconstruction system is proposed for audio reproduction with extended sweet spot and reduced reflections. An equivalent source method (ESM)-based sound field synthesis (SFS) approach, with the aid of dark zone minimization is adopted in the study. Conventional SFS that is based on the free-field assumption suffers from synthesis error due to boundary reflections. To tackle the problem, the proposed system utilizes convex optimization in designing array filters with both reproduction performance and acoustic contrast taken into consideration. Control points are deployed in the dark zone to minimize the reflections from the walls. Two approaches are employed to constrain the pressure and velocity in the dark zone. Pressure matching error (PME) and acoustic contrast (AC) are used as performance measures in simulations and experiments for a rectangular loudspeaker array. Perceptual Evaluation of Audio Quality (PEAQ) is also used to assess the audio reproduction quality. The results show that the pressure-constrained (PC) method yields better acoustic contrast, but poorer reproduction performance than the pressure-velocity constrained (PVC) method. A subjective listening test also indicates that the PVC method is the preferred method in a live room.

Binding and strategic selection in working memory: a lifespan dissociation.

PubMed

Sander, Myriam C; Werkle-Bergner, Markus; Lindenberger, Ulman

2011-09-01

Working memory (WM) shows a gradual increase during childhood, followed by accelerating decline from adulthood to old age. To examine these lifespan differences more closely, we asked 34 children (10-12 years), 40 younger adults (20-25 years), and 39 older adults (70-75 years) to perform a color change detection task. Load levels and encoding durations were varied for displays including targets only (Experiment 1) or targets plus distracters (Experiment 2, investigating a subsample of Experiment 1). WM performance was lower in older adults and children than in younger adults. Longer presentation times were associated with better performance in all age groups, presumably reflecting increasing effects of strategic selection mechanisms on WM performance. Children outperformed older adults when encoding times were short, and distracter effects were larger in children and older adults than in younger adults. We conclude that strategic selection in WM develops more slowly during childhood than basic binding operations, presumably reflecting the delay in maturation of frontal versus medio-temporal brain networks. In old age, both sets of mechanisms decline, reflecting senescent change in both networks. We discuss similarities to episodic memory development and address open questions for future research.

Characterization, optical properties and laser ablation behavior of epoxy resin coatings reinforced with high reflectivity ceramic particles

NASA Astrophysics Data System (ADS)

Li, Wenzhi; Kong, Jing; Wu, Taotao; Gao, Lihong; Ma, Zhuang; Liu, Yanbo; Wang, Fuchi; Wei, Chenghua; Wang, Lijun

2018-04-01

Thermal damage induced by high power energy, especially high power laser, significantly affects the lifetime and performance of equipment. High-reflectance coating/film has attracted considerable attention due to its good performance in the damage protection. Preparing a high-reflectance coating with high reaction endothermal enthalpy will effectively consume a large amount of incident energy and in turn protect the substrate from thermal damage. In this study, a low temperature process was used to prepare coatings onto substrate with complex shape and avoid thermal effect during molding. An advanced high reflection ceramic powder, La1‑xSrxTiO3+δ , was added in the epoxy adhesive matrix to improve the reflectivity of coating. The optical properties and laser ablation behaviors of coatings with different ceramic additive ratio of La1‑xSrxTiO3+δ and modified epoxy-La1‑xSrxTiO3+δ with ammonium polyphosphate coatings were investigated, respectively. We found that the reflectivity of coatings is extremely high due to mixed high-reflection La1‑xSrxTiO3+δ particles, up to 96% at 1070 nm, which can significantly improve the laser resistance. In addition, the ammonium polyphosphate modifies the residual carbon structure of epoxy resin from discontinuous fine particles structure to continuous and porous structure, which greatly enhances the thermal-insulation property of coating. Furthermore, the laser ablation threshold is improved obviously, which is from 800 W cm‑2 to 1000 W cm‑2.

Vision Screening

MedlinePlus

... testing when performed at a doctor's office. Corneal light reflex testing This simple test can be performed ... focuses on a penlight, the position of the light reflection from the front surface (cornea) of the ...

Color tunable low cost transparent heat reflector using copper and titanium oxide for energy saving application

PubMed Central

Dalapati, Goutam Kumar; Masudy-Panah, Saeid; Chua, Sing Teng; Sharma, Mohit; Wong, Ten It; Tan, Hui Ru; Chi, Dongzhi

2016-01-01

Multilayer coating structure comprising a copper (Cu) layer sandwiched between titanium dioxide (TiO2) were demonstrated as a transparent heat reflecting (THR) coating on glass for energy-saving window application. The main highlight is the utilization of Cu, a low-cost material, in-lieu of silver which is widely used in current commercial heat reflecting coating on glass. Color tunable transparent heat reflecting coating was realized through the design of multilayer structure and process optimization. The impact of thermal treatment on the overall performance of sputter deposited TiO2/Cu/TiO2 multilayer thin film on glass substrate is investigated in detail. Significant enhancement of transmittance in the visible range and reflectance in the infra-red (IR) region has been observed after thermal treatment of TiO2/Cu/TiO2 multilayer thin film at 500 °C due to the improvement of crystal quality of TiO2. Highest visible transmittance of 90% and IR reflectance of 85% at a wavelength of 1200 nm are demonstrated for the TiO2/Cu/TiO2 multilayer thin film after annealing at 500 °C. Performance of TiO2/Cu/TiO2 heat reflector coating decreases after thermal treatment at 600 °C. The wear performance of the TiO2/Cu/TiO2 multilayer structure has been evaluated through scratch hardness test. The present work shows promising characteristics of Cu-based THR coating for energy-saving building industry. PMID:26846687

REFLECTION OF PROPAGATING SLOW MAGNETO-ACOUSTIC WAVES IN HOT CORONAL LOOPS: MULTI-INSTRUMENT OBSERVATIONS AND NUMERICAL MODELING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mandal, Sudip; Banerjee, Dipankar; Pant, Vaibhav

Slow MHD waves are important tools for understanding coronal structures and dynamics. In this paper, we report a number of observations from the X-Ray Telescope (XRT) on board HINODE and Solar Dynamic Observatory /Atmospheric Imaging Assembly (AIA) of reflecting longitudinal waves in hot coronal loops. To our knowledge, this is the first report of this kind as seen from the XRT and simultaneously with the AIA. The wave appears after a micro-flare occurs at one of the footpoints. We estimate the density and temperature of the loop plasma by performing differential emission measure (DEM) analysis on the AIA image sequence.more » The estimated speed of propagation is comparable to or lower than the local sound speed, suggesting it to be a propagating slow wave. The intensity perturbation amplitude, in every case, falls very rapidly as the perturbation moves along the loop and eventually vanishes after one or more reflections. To check the consistency of such reflection signatures with the obtained loop parameters, we perform a 2.5D MHD simulation, which uses the parameters obtained from our observation as inputs, and perform forward modeling to synthesize AIA 94 Å images. Analyzing the synthesized images, we obtain the same properties of the observables as for the real observation. From the analysis we conclude that a footpoint heating can generate a slow wave which then reflects back and forth in the coronal loop before fading. Our analysis of the simulated data shows that the main agent for this damping is anisotropic thermal conduction.« less

Research of the impact of coupling between unit cells on performance of linear-to-circular polarization conversion metamaterial with half transmission and half reflection

NASA Astrophysics Data System (ADS)

Guo, Mengchao; Zhou, Kan; Wang, Xiaokun; Zhuang, Haiyan; Tang, Dongming; Zhang, Baoshan; Yang, Yi

2018-04-01

In this paper, the impact of coupling between unit cells on the performance of linear-to-circular polarization conversion metamaterial with half transmission and half reflection is analyzed by changing the distance between the unit cells. An equivalent electrical circuit model is then built to explain it based on the analysis. The simulated results show that, when the distance between the unit cells is 23 mm, this metamaterial converts half of the incident linearly-polarized wave into reflected left-hand circularly-polarized wave and converts the other half of it into transmitted left-hand circularly-polarized wave at 4.4 GHz; when the distance is 28 mm, this metamaterial reflects all of the incident linearly-polarized wave at 4.4 GHz; and when the distance is 32 mm, this metamaterial converts half of the incident linearly-polarized wave into reflected right-hand circularly-polarized wave and converts the other half of it into transmitted right-hand circularly-polarized wave at 4.4 GHz. The tunability is realized successfully. The analysis shows that the changes of coupling between unit cells lead to the changes of performance of this metamaterial. The coupling between the unit cells is then considered when building the equivalent electrical circuit model. The built equivalent electrical circuit model can be used to perfectly explain the simulated results, which confirms the validity of it. It can also give help to the design of tunable polarization conversion metamaterials.

Color tunable low cost transparent heat reflector using copper and titanium oxide for energy saving application.

PubMed

Dalapati, Goutam Kumar; Masudy-Panah, Saeid; Chua, Sing Teng; Sharma, Mohit; Wong, Ten It; Tan, Hui Ru; Chi, Dongzhi

2016-02-05

Multilayer coating structure comprising a copper (Cu) layer sandwiched between titanium dioxide (TiO2) were demonstrated as a transparent heat reflecting (THR) coating on glass for energy-saving window application. The main highlight is the utilization of Cu, a low-cost material, in-lieu of silver which is widely used in current commercial heat reflecting coating on glass. Color tunable transparent heat reflecting coating was realized through the design of multilayer structure and process optimization. The impact of thermal treatment on the overall performance of sputter deposited TiO2/Cu/TiO2 multilayer thin film on glass substrate is investigated in detail. Significant enhancement of transmittance in the visible range and reflectance in the infra-red (IR) region has been observed after thermal treatment of TiO2/Cu/TiO2 multilayer thin film at 500 °C due to the improvement of crystal quality of TiO2. Highest visible transmittance of 90% and IR reflectance of 85% at a wavelength of 1200 nm are demonstrated for the TiO2/Cu/TiO2 multilayer thin film after annealing at 500 °C. Performance of TiO2/Cu/TiO2 heat reflector coating decreases after thermal treatment at 600 °C. The wear performance of the TiO2/Cu/TiO2 multilayer structure has been evaluated through scratch hardness test. The present work shows promising characteristics of Cu-based THR coating for energy-saving building industry.

A fast color image enhancement algorithm based on Max Intensity Channel

PubMed Central

Sun, Wei; Han, Long; Guo, Baolong; Jia, Wenyan; Sun, Mingui

2014-01-01

In this paper, we extend image enhancement techniques based on the retinex theory imitating human visual perception of scenes containing high illumination variations. This extension achieves simultaneous dynamic range modification, color consistency, and lightness rendition without multi-scale Gaussian filtering which has a certain halo effect. The reflection component is analyzed based on the illumination and reflection imaging model. A new prior named Max Intensity Channel (MIC) is implemented assuming that the reflections of some points in the scene are very high in at least one color channel. Using this prior, the illumination of the scene is obtained directly by performing a gray-scale closing operation and a fast cross-bilateral filtering on the MIC of the input color image. Consequently, the reflection component of each RGB color channel can be determined from the illumination and reflection imaging model. The proposed algorithm estimates the illumination component which is relatively smooth and maintains the edge details in different regions. A satisfactory color rendition is achieved for a class of images that do not satisfy the gray-world assumption implicit to the theoretical foundation of the retinex. Experiments are carried out to compare the new method with several spatial and transform domain methods. Our results indicate that the new method is superior in enhancement applications, improves computation speed, and performs well for images with high illumination variations than other methods. Further comparisons of images from National Aeronautics and Space Administration and a wearable camera eButton have shown a high performance of the new method with better color restoration and preservation of image details. PMID:25110395

A fast color image enhancement algorithm based on Max Intensity Channel.

PubMed

Sun, Wei; Han, Long; Guo, Baolong; Jia, Wenyan; Sun, Mingui

2014-03-30

In this paper, we extend image enhancement techniques based on the retinex theory imitating human visual perception of scenes containing high illumination variations. This extension achieves simultaneous dynamic range modification, color consistency, and lightness rendition without multi-scale Gaussian filtering which has a certain halo effect. The reflection component is analyzed based on the illumination and reflection imaging model. A new prior named Max Intensity Channel (MIC) is implemented assuming that the reflections of some points in the scene are very high in at least one color channel. Using this prior, the illumination of the scene is obtained directly by performing a gray-scale closing operation and a fast cross-bilateral filtering on the MIC of the input color image. Consequently, the reflection component of each RGB color channel can be determined from the illumination and reflection imaging model. The proposed algorithm estimates the illumination component which is relatively smooth and maintains the edge details in different regions. A satisfactory color rendition is achieved for a class of images that do not satisfy the gray-world assumption implicit to the theoretical foundation of the retinex. Experiments are carried out to compare the new method with several spatial and transform domain methods. Our results indicate that the new method is superior in enhancement applications, improves computation speed, and performs well for images with high illumination variations than other methods. Further comparisons of images from National Aeronautics and Space Administration and a wearable camera eButton have shown a high performance of the new method with better color restoration and preservation of image details.

A fast color image enhancement algorithm based on Max Intensity Channel

NASA Astrophysics Data System (ADS)

Sun, Wei; Han, Long; Guo, Baolong; Jia, Wenyan; Sun, Mingui

2014-03-01

In this paper, we extend image enhancement techniques based on the retinex theory imitating human visual perception of scenes containing high illumination variations. This extension achieves simultaneous dynamic range modification, color consistency, and lightness rendition without multi-scale Gaussian filtering which has a certain halo effect. The reflection component is analyzed based on the illumination and reflection imaging model. A new prior named Max Intensity Channel (MIC) is implemented assuming that the reflections of some points in the scene are very high in at least one color channel. Using this prior, the illumination of the scene is obtained directly by performing a gray-scale closing operation and a fast cross-bilateral filtering on the MIC of the input color image. Consequently, the reflection component of each RGB color channel can be determined from the illumination and reflection imaging model. The proposed algorithm estimates the illumination component which is relatively smooth and maintains the edge details in different regions. A satisfactory color rendition is achieved for a class of images that do not satisfy the gray-world assumption implicit to the theoretical foundation of the retinex. Experiments are carried out to compare the new method with several spatial and transform domain methods. Our results indicate that the new method is superior in enhancement applications, improves computation speed, and performs well for images with high illumination variations than other methods. Further comparisons of images from National Aeronautics and Space Administration and a wearable camera eButton have shown a high performance of the new method with better color restoration and preservation of image details.

How Female Officers’ Performance in Non-Traditional U.S. Navy Shipboard Jobs Compares to Male Officers’ Performance

DTIC Science & Technology

1988-12-01

SAS Institute Inc. 14. Kanter, Rosabeth M., Men and Women of the Corporation, Basic Books, Inc., 1977. 15. Snyder, Mark, " Self -Fulfilling Stereotypes ...this thesis are those of the author and do not reflect the official policy or position of the Department of Defense or the U.S. Government. 17 Cosati... reflection upon the courageous manhood of the country to pass a law inviting women to Join the armed forces in order to win a battle. Take the women into

A Practical and Portable Solids-State Electronic Terahertz Imaging System

PubMed Central

Smart, Ken; Du, Jia; Li, Li; Wang, David; Leslie, Keith; Ji, Fan; Li, Xiang Dong; Zeng, Da Zhang

2016-01-01

A practical compact solid-state terahertz imaging system is presented. Various beam guiding architectures were explored and hardware performance assessed to improve its compactness, robustness, multi-functionality and simplicity of operation. The system performance in terms of image resolution, signal-to-noise ratio, the electronic signal modulation versus optical chopper, is evaluated and discussed. The system can be conveniently switched between transmission and reflection mode according to the application. A range of imaging application scenarios was explored and images of high visual quality were obtained in both transmission and reflection mode. PMID:27110791

Kotov during Albedo Experiment in the SM

NASA Image and Video Library

2013-11-18

ISS038-E-005022 (20 Nov. 2013) --- At a window in the International Space Station?s Zvezda Service Module, Russian cosmonaut Oleg Kotov, Expedition 38 commander, uses a digital camera photospectral system to perform a session for the Albedo Experiment. The experiment measures Earth?s albedo, or the amount of solar radiation reflected from the surface, in the hopes to develop methods to harness the reflected radiation to supplement the station?s power supply. The light reflection phenomenon is measured in units called albedo.

Kotov during Albedo Experiment in the SM

NASA Image and Video Library

2013-11-18

ISS038-E-005014 (20 Nov. 2013) --- At a window in the International Space Station’s Zvezda Service Module, Russian cosmonaut Oleg Kotov, Expedition 38 commander, uses a digital camera photospectral system to perform a session for the Albedo Experiment. The experiment measures Earth’s albedo, or the amount of solar radiation reflected from the surface, in the hopes to develop methods to harness the reflected radiation to supplement the station’s power supply. The light reflection phenomenon is measured in units called albedo.

Kotov during Albedo Experiment in the SM

NASA Image and Video Library

2013-11-18

ISS038-E-005023 (20 Nov. 2013) --- At a window in the International Space Station?s Zvezda Service Module, Russian cosmonaut Oleg Kotov, Expedition 38 commander, uses a digital camera photospectral system to perform a session for the Albedo Experiment. The experiment measures Earth?s albedo, or the amount of solar radiation reflected from the surface, in the hopes to develop methods to harness the reflected radiation to supplement the station?s power supply. The light reflection phenomenon is measured in units called albedo.

Kotov during Albedo Experiment in the SM

NASA Image and Video Library

2013-11-18

ISS038-E-005031 (20 Nov. 2013) --- At a window in the International Space Station?s Zvezda Service Module, Russian cosmonaut Oleg Kotov, Expedition 38 commander, uses a digital camera photospectral system to perform a session for the Albedo Experiment. The experiment measures Earth?s albedo, or the amount of solar radiation reflected from the surface, in the hopes to develop methods to harness the reflected radiation to supplement the station?s power supply. The light reflection phenomenon is measured in units called albedo.

Kotov during Albedo Experiment in the SM

NASA Image and Video Library

2013-11-18

ISS038-E-005016 (20 Nov. 2013) --- At a window in the International Space Station?s Zvezda Service Module, Russian cosmonaut Oleg Kotov, Expedition 38 commander, uses a digital camera photospectral system to perform a session for the Albedo Experiment. The experiment measures Earth?s albedo, or the amount of solar radiation reflected from the surface, in the hopes to develop methods to harness the reflected radiation to supplement the station?s power supply. The light reflection phenomenon is measured in units called albedo.

Kotov during Albedo Experiment in the SM

NASA Image and Video Library

2013-11-18

ISS038-E-005019 (20 Nov. 2013) --- At a window in the International Space Station?s Zvezda Service Module, Russian cosmonaut Oleg Kotov, Expedition 38 commander, uses a digital camera photospectral system to perform a session for the Albedo Experiment. The experiment measures Earth?s albedo, or the amount of solar radiation reflected from the surface, in the hopes to develop methods to harness the reflected radiation to supplement the station?s power supply. The light reflection phenomenon is measured in units called albedo.

Synthetic Image Generator Model; Application of View Angle Dependent Reflectivity Components and Performance Evaluation in the Visible Region

DTIC Science & Technology

1993-02-01

3.1.2. Modeling of Environment ....................... 6 3.1.3. Ray Tracing and Radiosity ..................... 8 3.2. Reflectivity Review...SIG modeling is dependent on proper treatment of its effects. 3.1.3 Ray Tracing and Radiosity Prior to reviewing reflectivity, a brief look is made of...methods of applying complex theoretical energy propagation algorithms. Two such methods are ray tracing and radiosity (Goral, et al, 1984). Ray tracing is a

Durable thin film coatings for reflectors used in low earth orbit

NASA Technical Reports Server (NTRS)

Mcclure, Donald J.

1989-01-01

This paper discusses the properties of thin film coatings used to provide a durable reflective surface for solar concentrators used in the solar dynamic system designed for the Space Station. The material system to be used consists of an adhesion promotion layer, a silver reflective layer, and a protective layer of aluminum oxide and silicon dioxide. The performance characteristics of this system are described and compared to those of several alternative systems which use aluminum as the reflective layer.

Nd:YAG-laser-based time-domain reflectometry measurements of the intrinsic reflection signature from PMMA fiber splices

NASA Astrophysics Data System (ADS)

Lawson, Christopher M.; Michael, Robert R., Jr.; Dressel, Earl M.; Harmony, David W.

1991-12-01

Optical time domain reflectometry (OTDR) measurements have been performed on polished polymethylmethacrylate (PMMA) plastic fiber splices. After the dominant splice reflection sources due to surface roughness, inexact index matching, and fiber core misalignment were eliminated, an intrinsic OTDR signature 3 - 8 dB above the Rayleigh backscatter floor remained with all tested fibers. This minimum splice reflectivity exhibits characteristics that are consistent with sub-surface polymer damage and can be used for detection of PMMA fiber splices.

The Myths and Realities of Simulations in Performance Technology.

ERIC Educational Resources Information Center

Thiagarajan, Sivasailam

1998-01-01

Examines misconceptions about simulations for performance technology concerning what they reflect, varieties, uses (instruction, awareness, performance assessment, team building, transfer, research, therapy), levels of fidelity, design approaches, formats (graphic models; card, race, and cyclical games; interactive fiction; production simulations;…

Dependence on Solar Phase Angle and Grain Size of the Spectral Reflectance of the Railroad Valley Playa for GOSAT/GOSAT-2 Vicarious Calibration

NASA Astrophysics Data System (ADS)

Arai, T.; Matsunaga, T.

2017-12-01

GOSAT and the next generation GOSAT-2 satellites estimate the concentration of greenhouse gasses, and distribution of aerosol and cloud to observe solar light reflection and radiation from surface and atmosphere of the Earth. Precise information of the surface and the bidirectional reflectance distribution function (BRDF) are required for the estimation because the surface reflectance of solar light varies with the observation geometry and the surface condition. The purpose of this study is to search an appropriate BRDF model of the GOSAT calibration site (Railroad Valley playa). In 2017, JAXA, NIES, and NASA/OCO-2 teams collaboratively performed 9th vicarious experiments by the simultaneous observation with GOSAT, OCO-2, and ground-based equipment (Kuze et al., 2014) at the Railroad Valley from June 25 to 30. We performed the BRDF measurement to observe solar light reflection by varying with observed angles using a spectroradiometer (FieldSpec4, ASD Inc.) mounted on a one-axis goniometer. The surface sand was shifted to several sizes of grain (75, 125, 250, 500, and 1000 μm), which was measured for the limited area of 5mm diameter with a collimating lens (74-UV, OceanOptics). The BRDF parameters for the observed reflectance were determined by the least squares fitting with the free parameters of a single scattering albedo and an asymmetric factor (Hapke, 2012) for the ultraviolet to near infrared wavelength bands of GOSAT. The resulting value of the single scattering albedo increased with decreasing the grain size of the sands. The observed reflectance of the fine grain sands (below 250 μm) is not varied with observed phase angles (solar incident light - surface sand - detector) as a Lambertian reflectance, but the spectra of coarse grain sands (above 500 μm) are varied with the observation angles. Therefore, a priori information of the target surface such as grain size is required for the determination of the precise reflectance of the target.

Fabry-Perot color filter with antireflective nano-grating surface

NASA Astrophysics Data System (ADS)

Zhang, Jiayuan; Zhang, Jie; Dong, Xiaoxuan

2013-12-01

In order to improve the color saturation of reflective Fabry-Perot(FP) color filter, we proposed a reflective color filter incorporating FP resonator with a dielectric grating. The FP resonator consists of high reflection metal film, dielectric film and semi-transparent metal film. The dielectric grating, above the semi-transparent metal film, can reduce the reflection from the semi-transparent film in which case high saturation will be achieved. By using Finite Difference Time Domain(FDTD) method, the reflection spectra characteristic is analyzed as a function of duty cycle, period, refractive index and thickness of the dielectric grating. Based on the simulation results, a high performance color filter is proposed by optimizing the structural parameters. The full width at half-maximum (FWHM) reflection spectrum of the filters are reduced from 100 nm to 70 nm and the peak reflection efficiency of the filters are about 90%. The overlap of the tricolor output spectra decreases effectively, which will increase the color saturation of the color filter.

LAI inversion from optical reflectance using a neural network trained with a multiple scattering model

NASA Technical Reports Server (NTRS)

Smith, James A.

1992-01-01

The inversion of the leaf area index (LAI) canopy parameter from optical spectral reflectance measurements is obtained using a backpropagation artificial neural network trained using input-output pairs generated by a multiple scattering reflectance model. The problem of LAI estimation over sparse canopies (LAI < 1.0) with varying soil reflectance backgrounds is particularly difficult. Standard multiple regression methods applied to canopies within a single homogeneous soil type yield good results but perform unacceptably when applied across soil boundaries, resulting in absolute percentage errors of >1000 percent for low LAI. Minimization methods applied to merit functions constructed from differences between measured reflectances and predicted reflectances using multiple-scattering models are unacceptably sensitive to a good initial guess for the desired parameter. In contrast, the neural network reported generally yields absolute percentage errors of <30 percent when weighting coefficients trained on one soil type were applied to predicted canopy reflectance at a different soil background.

High-purity silica reflecting heat shield development

NASA Technical Reports Server (NTRS)

Congdon, W. M.

1974-01-01

A high-purity, fused-silica reflecting heat shield for the thermal protection of outer-planet probes was developed. Factors that strongly influence the performance of a silica heat shield were studied. Silica-bonded silica configurations, each prepared by a different technique, were investigated and rated according to its relative merits. Slip-casting was selected as the preferred fabrication method because it produced good reflectivity and good strength, and is relatively easy to scale up for a full-size outer-planet probe. The slips were cast using a variety of different particle sizes: continuous particle-size slips; monodisperse particle-size slips; and blends of monodisperse particle-size slips were studied. In general, smaller particles gave the highest reflectance. The monodisperse slips as well as the blend slips gave a higher reflectance than the continuous particle-size slips. An upgraded and fused natural quartz was used to study the effects of microstructure on reflectance and as the baseline to ascertain the increase in reflectance obtained from using a higher-purity synthetic material.

Do case-generic measures of queue performance for bypass surgery accurately reflect the waiting-list experiences of those most urgent?

PubMed

Burstein, Jason; Lee, Douglas S; Alter, David A

2006-02-01

Queue performance is typically assessed using generic measures, which capture the queue in aggregate. The objective of this study was to examine whether case-generic measures of queue performance appropriately reflected the waiting-list experiences of those patients with greatest disease severity. We examined the queue for isolated coronary artery bypass grafting (CABG) in Ontario between April 1993 and March 2000 using data obtained from the Cardiac Care Network. Our primary measure of queue performance was the proportion of patients who received their bypass surgery within their recommended maximum waiting times (%RMWTs) in any given month. We compared case-generic measures of queue performance to case-specific measures of queue performance stratified by urgency level. The queue was largely comprised of elective cases ranging from 73% (1993) to 57%(1999). Urgent patients comprised the minority of the queue ranging from 14% (1993) to 20% (1999). Case-generic month-to-month variations in the percentage of cases completed within RMWTs (an aggregated waiting list measure encompassing the characteristics of all patients in the queue) closely resembled the experiences of elective patients (R2 = 0.81), but conversely, bore little relationship to the waiting-list experiences of those most urgent (R2 = 0.15). Case-generic measures of queue performance for bypass surgery in Ontario were not reflective of the waiting-list experiences of those most urgent. Our results reinforce the concept that urgency-specific waiting list monitoring systems are required to best evaluate and appropriately respond to fluctuations in queue performance.

The simulation study on optical target laser active detection performance

NASA Astrophysics Data System (ADS)

Li, Ying-chun; Hou, Zhao-fei; Fan, Youchen

2014-12-01

According to the working principle of laser active detection system, the paper establishes the optical target laser active detection simulation system, carry out the simulation study on the detection process and detection performance of the system. For instance, the performance model such as the laser emitting, the laser propagation in the atmosphere, the reflection of optical target, the receiver detection system, the signal processing and recognition. We focus on the analysis and modeling the relationship between the laser emitting angle and defocus amount and "cat eye" effect echo laser in the reflection of optical target. Further, in the paper some performance index such as operating range, SNR and the probability of the system have been simulated. The parameters including laser emitting parameters, the reflection of the optical target and the laser propagation in the atmosphere which make a great influence on the performance of the optical target laser active detection system. Finally, using the object-oriented software design methods, the laser active detection system with the opening type, complete function and operating platform, realizes the process simulation that the detection system detect and recognize the optical target, complete the performance simulation of each subsystem, and generate the data report and the graph. It can make the laser active detection system performance models more intuitive because of the visible simulation process. The simulation data obtained from the system provide a reference to adjust the structure of the system parameters. And it provides theoretical and technical support for the top level design of the optical target laser active detection system and performance index optimization.

Multi-beam reflections with flexible control of polarizations by using anisotropic metasurfaces

NASA Astrophysics Data System (ADS)

Ma, Hui Feng; Liu, Yan Qing; Luan, Kang; Cui, Tie Jun

2016-12-01

We propose a method to convert linearly polarized incident electromagnetic waves fed by a single source into multi-beam reflections with independent control of polarizations based on anisotropic metasurface at microwave frequencies. The metasurface is composed of Jerusalem Cross structures and grounded plane spaced by a dielectric substrate. By designing the reflection-phase distributions of the anisotropic metasurface along the x and y directions, the x- and y-polarized incident waves can be manipulated independently to realize multi-beam reflections. When the x- and y-polarized reflected beams are designed to the same direction with equal amplitude, the polarization state of the beam will be only controlled by the phase difference between the x- and y-polarized reflected waves. Three examples are presented to show the multi-beam reflections with flexible control of polarizations by using anisotropic metasurfaces and excellent performance. Particularly, we designed, fabricated, and measured an anisotropic metasurface for two reflected beams with one linearly polarized and the other circularly polarized. The measurement results have good agreement with the simulations in a broad bandwidth.

Surface reflectance retrieval from imaging spectrometer data using three atmospheric codes

NASA Astrophysics Data System (ADS)

Staenz, Karl; Williams, Daniel J.; Fedosejevs, Gunar; Teillet, Phil M.

1994-12-01

Surface reflectance retrieval from imaging spectrometer data has become important for quantitative information extraction in many application areas. In order to calculate surface reflectance from remotely measured radiance, radiative transfer codes play an important role for removal of the scattering and gaseous absorption effects of the atmosphere. The present study evaluates surface reflectances retrieved from airborne visible/infrared imaging spectrometer (AVIRIS) data using three radiative transfer codes: modified 5S (M5S), 6S, and MODTRAN2. Comparisons of the retrieved surface reflectance with ground-based reflectance were made for different target types such as asphalt, gravel, grass/soil mixture (soccer field), and water (Sooke Lake). The results indicate that the estimation of the atmospheric water vapor content is important for an accurate surface reflectance retrieval regardless of the radiative transfer code used. For the present atmospheric conditions, a difference of 0.1 in aerosol optical depth had little impact on the retrieved surface reflectance. The performance of MODTRAN2 is superior in the gas absorption regions compared to M5S and 6S.

Multi-beam reflections with flexible control of polarizations by using anisotropic metasurfaces

PubMed Central

Ma, Hui Feng; Liu, Yan Qing; Luan, Kang; Cui, Tie Jun

2016-01-01

We propose a method to convert linearly polarized incident electromagnetic waves fed by a single source into multi-beam reflections with independent control of polarizations based on anisotropic metasurface at microwave frequencies. The metasurface is composed of Jerusalem Cross structures and grounded plane spaced by a dielectric substrate. By designing the reflection-phase distributions of the anisotropic metasurface along the x and y directions, the x- and y-polarized incident waves can be manipulated independently to realize multi-beam reflections. When the x- and y-polarized reflected beams are designed to the same direction with equal amplitude, the polarization state of the beam will be only controlled by the phase difference between the x- and y-polarized reflected waves. Three examples are presented to show the multi-beam reflections with flexible control of polarizations by using anisotropic metasurfaces and excellent performance. Particularly, we designed, fabricated, and measured an anisotropic metasurface for two reflected beams with one linearly polarized and the other circularly polarized. The measurement results have good agreement with the simulations in a broad bandwidth. PMID:28000734

Gender Differences in Performance Predictions: Evidence from the Cognitive Reflection Test

PubMed Central

Ring, Patrick; Neyse, Levent; David-Barett, Tamas; Schmidt, Ulrich

2016-01-01

This paper studies performance predictions in the 7-item Cognitive Reflection Test (CRT) and whether they differ by gender. After participants completed the CRT, they predicted their own (i), the other participants’ (ii), men’s (iii), and women’s (iv) number of correct answers. In keeping with existing literature, men scored higher on the CRT than women and both men and women were too optimistic about their own performance. When we compare gender-specific predictions, we observe that men think they perform significantly better than other men and do so significantly more than women. The equality between women’s predictions about their own performance and their female peers cannot be rejected. Our findings contribute to the growing literature on the underpinnings of behavior in economics and in psychology by uncovering gender differences in confidence about one’s ability relative to same and opposite sex peers. PMID:27847487

Gender Differences in Performance Predictions: Evidence from the Cognitive Reflection Test.

PubMed

Ring, Patrick; Neyse, Levent; David-Barett, Tamas; Schmidt, Ulrich

2016-01-01

This paper studies performance predictions in the 7-item Cognitive Reflection Test (CRT) and whether they differ by gender. After participants completed the CRT, they predicted their own (i), the other participants' (ii), men's (iii), and women's (iv) number of correct answers. In keeping with existing literature, men scored higher on the CRT than women and both men and women were too optimistic about their own performance. When we compare gender-specific predictions, we observe that men think they perform significantly better than other men and do so significantly more than women. The equality between women's predictions about their own performance and their female peers cannot be rejected. Our findings contribute to the growing literature on the underpinnings of behavior in economics and in psychology by uncovering gender differences in confidence about one's ability relative to same and opposite sex peers.

Modeling and Sound Insulation Performance Analysis of Two Honeycomb-hole Coatings

NASA Astrophysics Data System (ADS)

Ye, H. F.; Tao, M.; Zhang, W. Z.

2018-05-01

During the sound transmission loss test in the standing-wave tube, the unavoidable reflected wave from the termination of downstream tube would affect the precision measurement of sound transmission loss(TL). However, it can be solved by defining the non-reflected boundary conditions when modeling based on the finite element method. Then, the model has been validated by comparing with the analytical method. Based on the present model, the sound insulation performance of two types of honeycomb-hole coatings have been analyzed and discussed. Moreover, the changes of parameters play an important role on the sound insulation performance of honeycomb-hole coating and the negative Poisson’s ratio honeycomb-hole coating has better sound insulation performance at special frequencies. Finally, it is summarized that sound insulation performance is the result of various factors that include the impedance changes, the waveform transformation and so on.

Metasurface-based anti-reflection coatings at optical frequencies

NASA Astrophysics Data System (ADS)

Monti, Alessio; Alù, Andrea; Toscano, Alessandro; Bilotti, Filiberto

2018-05-01

In this manuscript, we propose a metasurface approach for the reduction of electromagnetic reflection from an arbitrary air‑dielectric interface. The proposed technique exploits the exotic optical response of plasmonic nanoparticles to achieve complete cancellation of the field reflected by a dielectric substrate by means of destructive interference. Differently from other, earlier anti-reflection approaches based on nanoparticles, our design scheme is supported by a simple transmission-line formulation that allows a closed-form characterization of the anti-reflection performance of a nanoparticle array. Furthermore, since the working principle of the proposed devices relies on an average effect that does not critically depend on the array geometry, our approach enables low-cost production and easy scalability to large sizes. Our theoretical considerations are supported by full-wave simulations confirming the effectiveness of this design principle.

Anisotropic reflectance from turbid media. II. Measurements.

PubMed

Neuman, Magnus; Edström, Per

2010-05-01

The anisotropic reflectance from turbid media predicted using the radiative transfer based DORT2002 model is experimentally verified through goniophotometric measurements. A set of paper samples with varying amounts of dye and thickness is prepared, and their angle resolved reflectance is measured. An alleged perfect diffusor is also included. The corresponding simulations are performed. A complete agreement between the measurements and model predictions is seen regarding the characteristics of the anisotropy. They show that relatively more light is reflected at large polar angles when the absorption or illumination angle is increased or when the medium thickness is decreased. This is due to the relative amount of near-surface bulk scattering increasing in these cases. This affects the application of the Kubelka-Munk model as well as standards for reflectance measurements and calibration routines.

Spontaneous Self-Distancing and Adaptive Self-Reflection Across Adolescence

PubMed Central

White, Rachel E.; Kross, Ethan; Duckworth, Angela L.

2015-01-01

Experiments performed primarily with adults show that self-distancing facilitates adaptive self-reflection. However, no research has investigated whether adolescents spontaneously engage in this process or whether doing so is linked to adaptive outcomes. In this study, 226 African American adolescents, aged 11 to 20, reflected on an anger-related interpersonal experience. As expected, spontaneous self-distancing during reflection predicted lower levels of emotional reactivity by leading adolescents to reconstrue (rather than recount) their experience and blame their partner less. Moreover, the inverse relation between self-distancing and emotional reactivity strengthened with age. These findings highlight the role that self-distancing plays in fostering adaptive self-reflection in adolescence, and begin to elucidate the role that development plays in enhancing the benefits of engaging in this process. PMID:25876213

Mid-Infrared Reflectance Imaging of Thermal-Barrier Coatings

NASA Technical Reports Server (NTRS)

Edlridge, Jeffrey I.; Martin, Richard E.

2009-01-01

An apparatus for mid-infrared reflectance imaging has been developed as means of inspecting for subsurface damage in thermal-barrier coatings (TBCs). The apparatus is designed, more specifically, for imaging the progression of buried delamination cracks in plasma-sprayed yttria-stabilized zirconia coatings on turbine-engine components. Progression of TBC delamination occurs by the formation of buried cracks that grow and then link together to produce eventual TBC spallation. The mid-infrared reflectance imaging system described here makes it possible to see delamination progression that is invisible to the unaided eye, and therefore give sufficiently advanced warning before delamination progression adversely affects engine performance and safety. The apparatus (see figure) includes a commercial mid-infrared camera that contains a liquid-nitrogen-cooled focal plane indium antimonide photodetector array, and imaging is restricted by a narrow bandpass centered at wavelength of 4 microns. This narrow wavelength range centered at 4 microns was chosen because (1) it enables avoidance of interfering absorptions by atmospheric OH and CO2 at 3 and 4.25 microns, respectively; and (2) the coating material exhibits maximum transparency in this wavelength range. Delamination contrast is produced in the midinfrared reflectance images because the introduction of cracks into the TBC creates an internal TBC/air-gap interface with a high diffuse reflectivity of 0.81, resulting in substantially higher reflectance of mid-infrared radiation in regions that contain buried delamination cracks. The camera is positioned a short distance (.12 cm) from the specimen. The mid-infrared illumination is generated by a 50-watt silicon carbide source positioned to the side of the mid-infrared camera, and the illumination is collimated and reflected onto the specimen by a 6.35-cm-diameter off-axis paraboloidal mirror. Because the collected images are of a steady-state reflected intensity (in contrast to the transient thermal response observed in infrared thermography), collection times can be lengthened to whatever extent needed to achieve desired signal-to-noise ratios. Each image is digitized, and the resulting data are processed in several steps to obtain a true mid-infrared reflectance image. The raw image includes thermal radiation emitted by the specimen in addition to the desired reflected radiation. The thermal-radiation contribution is eliminated by subtracting the image obtained with the illumination off from the image obtained with the illumination on. A flat-field correction is then made to remove the effects of non-uniformities in the illumination level and pixel-to-pixel variations in sensitivity. This correction is performed by normalizing to an image of a standard object that has a known reflectance at a wavelength of 4 microns. After correction, each pixel value is proportional to the reflectance (at a wavelength of 4-microns) at the corresponding location on the specimen. Mid-infrared reflectance imaging of specimens that were thermally cyc led for different numbers of cycles was performed and demonstrated t hat mid-infrared reflectance imaging was able to monitor the gradual delamination progression that occurs with continued thermal cycling . Reproducible values were obtained for the reflectance associated w ith an attached and fully delaminated TBC, so that intermediate refle ctance values could be interpreted to successfully predict the numbe r of thermal cycles to failure.

Electrophysiological Correlates of Impaired Reading in Dyslexic Pre-Adolescent Children

ERIC Educational Resources Information Center

Araujo, Susana; Bramao, Ines; Faisca, Luis; Petersson, Karl Magnus; Reis, Alexandra

2012-01-01

In this study, event related potentials (ERPs) were used to investigate the extent to which dyslexics (aged 9-13 years) differ from normally reading controls in early ERPs, which reflect prelexical orthographic processing, and in late ERPs, which reflect implicit phonological processing. The participants performed an implicit reading task, which…

On Mature Reflection: "Strange Objects" and the Cultivation of Reflective Reading.

ERIC Educational Resources Information Center

Heyde, Emma

2000-01-01

Examines Gary Crew's novel written for a young adult audience, called "Strange Objects," a story containing verifiable historical fact interwoven with elements of fiction and the supernatural. Shows how the numerous genres and viewpoints in the book challenge and contradict one another, forcing young readers to perform resistant readings…

Educating Reflexive Practitioners: Casting Graduate Teaching Assistants as Mentors in First-Year Classrooms

ERIC Educational Resources Information Center

Henry, Jim; Bruland, Holly H.

2010-01-01

Reflective practice has become a mainstay in many inquiries into teaching and learning, presenting reflective practitioners with the challenge of accounting for their own institutional positions when interpreting student performance in the binary teacher-student configurations of most classrooms. This study analyzes the perspectives of TAs cast as…

Examining Transcription, Autonomy and Reflective Practice in Language Development

ERIC Educational Resources Information Center

Cooke, Simon D.

2013-01-01

This pilot study explores language development among a class of L2 students who were required to transcribe and reflect upon spoken performances. The class was given tasks for self and peer-evaluation and afforded the opportunity to assume more responsibility for assessing language development of both themselves and their peers. Several studies…

Evaluating an Objective Structured Clinical Examination (OSCE) Adapted for Social Work

ERIC Educational Resources Information Center

Bogo, Marion; Regehr, Cheryl; Katz, Ellen; Logie, Carmen; Tufford, Lea; Litvack, Andrea

2012-01-01

Objectives: To evaluate an objective structured clinical examination (OSCE) adapted for social work in a lab course and examine the degree to which it predicts competence in the practicum. Method: 125 Masters students participated in a one-scenario OSCE and wrote responses to standardized reflection questions. OSCE performance and reflections were…

Experience With Intravascular Ultrasound Imaging Of Human Atherosclerotic Arteries

NASA Astrophysics Data System (ADS)

Mallery, John A.; Gessert, James M.; Maciel, Mario; Tobis, John M.; Griffith, James M.; Berns, Michael W.; Henry, Walter L.

1989-08-01

Normal human arteries have a well-defined structure on intravascular images. The intima appears very thin and is most likely represented by a bright reflection arising from the internal elastic lamina. The smooth muscle tunica media is echo-lucent on the ultrasound image and appears as a dark band separating the intima from the adventitia. The adventitia is a brightly reflective layer of variable thickness. The thickness of the intima, and therefore of the atherosclerotic plaque can be accurately measured from the ultrasound images and correlates well with histology. Calcification within the wall of arteries is seen as bright echo reflection with shadowing of the peripheral wall. Fibrotic regions are highly reflective but do not shadow. Necrotic liquid regions within advanced atherosclerotic plaques are seen on ultrasound images as large lucent zones surrounded by echogenic tissue. Imaging can be performed before and after interventional procedures, such as laser angioplasty, balloon angioplasty and atherectomy. Intravascular ultrasound appears to provide an imaging modality for identifying the histologic characteristics of diseased arteries and for quantifying plaque thickness. It might be possible to perform such quantification to evaluate the results of interventional procedures.

Evidence that logical reasoning depends on conscious processing.

PubMed

DeWall, C Nathan; Baumeister, Roy F; Masicampo, E J

2008-09-01

Humans, unlike other animals, are equipped with a powerful brain that permits conscious awareness and reflection. A growing trend in psychological science has questioned the benefits of consciousness, however. Testing a hypothesis advanced by [Lieberman, M. D., Gaunt, R., Gilbert, D. T., & Trope, Y. (2002). Reflection and reflexion: A social cognitive neuroscience approach to attributional inference. Advances in Experimental Social Psychology, 34, 199-249], four studies suggested that the conscious, reflective processing system is vital for logical reasoning. Substantial decrements in logical reasoning were found when a cognitive load manipulation preoccupied conscious processing, while hampering the nonconscious system with consciously suppressed thoughts failed to impair reasoning (Experiment 1). Nonconscious activation (priming) of the idea of logical reasoning increased the activation of logic-relevant concepts, but failed to improve logical reasoning performance (Experiments 2a-2c) unless the logical conclusions were largely intuitive and thus not reliant on logical reasoning (Experiment 3). Meanwhile, stimulating the conscious goal of reasoning well led to improvements in reasoning performance (Experiment 4). These findings offer evidence that logical reasoning is aided by the conscious, reflective processing system.

Optical and x-ray alignment approaches for off-plane reflection gratings

NASA Astrophysics Data System (ADS)

Allured, Ryan; Donovan, Benjamin D.; DeRoo, Casey T.; Marlowe, Hannah R.; McEntaffer, Randall L.; Tutt, James H.; Cheimets, Peter N.; Hertz, Edward; Smith, Randall K.; Burwitz, Vadim; Hartner, Gisela; Menz, Benedikt

2015-09-01

Off-plane reflection gratings offer the potential for high-resolution, high-throughput X-ray spectroscopy on future missions. Typically, the gratings are placed in the path of a converging beam from an X-ray telescope. In the off-plane reflection grating case, these gratings must be co-aligned such that their diffracted spectra overlap at the focal plane. Misalignments degrade spectral resolution and effective area. In-situ X-ray alignment of a pair of off-plane reflection gratings in the path of a silicon pore optics module has been performed at the MPE PANTER beamline in Germany. However, in-situ X-ray alignment may not be feasible when assembling all of the gratings required for a satellite mission. In that event, optical methods must be developed to achieve spectral alignment. We have developed an alignment approach utilizing a Shack-Hartmann wavefront sensor and diffraction of an ultraviolet laser. We are fabricating the necessary hardware, and will be taking a prototype grating module to an X-ray beamline for performance testing following assembly and alignment.

Creation and Validation of Sintered PTFE BRDF Targets & Standards

PubMed Central

Durell, Christopher; Scharpf, Dan; McKee, Greg; L’Heureux, Michelle; Georgiev, Georgi; Obein, Gael; Cooksey, Catherine

2016-01-01

Sintered polytetrafluoroethylene (PTFE) is an extremely stable, near-perfect Lambertian reflecting diffuser and calibration standard material that has been used by national labs, space, aerospace and commercial sectors for over two decades. New uncertainty targets of 2 % on-orbit absolute validation in the Earth Observing Systems community have challenged the industry to improve is characterization and knowledge of almost every aspect of radiometric performance (space and ground). Assuming “near perfect” reflectance for angular dependent measurements is no longer going to suffice for many program needs. The total hemispherical spectral reflectance provides a good mark of general performance; but, without the angular characterization of bidirectional reflectance distribution function (BRDF) measurements, critical data is missing from many applications and uncertainty budgets. Therefore, traceable BRDF measurement capability is needed to characterize sintered PTFE’s angular response and provide a full uncertainty profile to users. This paper presents preliminary comparison measurements of the BRDF of sintered PTFE from several laboratories to better quantify the BRDF of sintered PTFE, assess the BRDF measurement comparability between laboratories, and improve estimates of measurement uncertainties under laboratory conditions. PMID:26900206

Creation and Validation of Sintered PTFE BRDF Targets & Standards.

PubMed

Durell, Christopher; Scharpf, Dan; McKee, Greg; L'Heureux, Michelle; Georgiev, Georgi; Obein, Gael; Cooksey, Catherine

2015-09-21

Sintered polytetrafluoroethylene (PTFE) is an extremely stable, near-perfect Lambertian reflecting diffuser and calibration standard material that has been used by national labs, space, aerospace and commercial sectors for over two decades. New uncertainty targets of 2 % on-orbit absolute validation in the Earth Observing Systems community have challenged the industry to improve is characterization and knowledge of almost every aspect of radiometric performance (space and ground). Assuming "near perfect" reflectance for angular dependent measurements is no longer going to suffice for many program needs. The total hemispherical spectral reflectance provides a good mark of general performance; but, without the angular characterization of bidirectional reflectance distribution function (BRDF) measurements, critical data is missing from many applications and uncertainty budgets. Therefore, traceable BRDF measurement capability is needed to characterize sintered PTFE's angular response and provide a full uncertainty profile to users. This paper presents preliminary comparison measurements of the BRDF of sintered PTFE from several laboratories to better quantify the BRDF of sintered PTFE, assess the BRDF measurement comparability between laboratories, and improve estimates of measurement uncertainties under laboratory conditions.

ODERACS 2 White Spheres Optical Calibration Report

NASA Technical Reports Server (NTRS)

Culp, Robert D.; Gravseth, Ian; Gloor, Jason; Wantuch, Todd

1995-01-01

This report documents the status of the Orbital Debris Radar Calibration Spheres (ODERACS) 2 white spheres optical calibration study. The purpose of this study is to determine the spectral reflectivity and scattering characteristics in the visible wavelength region for the white spheres that were added to the project in the fall, 1994. Laboratory measurements were performed upon these objects and an analysis of the resulting data was conducted. These measurements are performed by illuminating the objects with a collimated beam of light and measuring the reflected light versus the phase angle. The phase angle is defined as the angle between the light source and the sensor, as viewed from the object. By measuring the reflected signal at the various phase angles, one is able to estimate the reflectance properties of the object. The methodology used in taking the measurements and reducing the data are presented. The results of this study will be used to support the calibration of ground-based optical instruments used in support of space debris research. Visible measurements will be made by the GEODDS, NASA and ILADOT telescopes.

Use of borehole radar reflection logging to monitor steam-enhanced remediation in fractured limestone-results of numerical modelling and a field experiment

USGS Publications Warehouse

Gregoire, C.; Joesten, P.K.; Lane, J.W.

2006-01-01

Ground penetrating radar is an efficient geophysical method for the detection and location of fractures and fracture zones in electrically resistive rocks. In this study, the use of down-hole (borehole) radar reflection logs to monitor the injection of steam in fractured rocks was tested as part of a field-scale, steam-enhanced remediation pilot study conducted at a fractured limestone quarry contaminated with chlorinated hydrocarbons at the former Loring Air Force Base, Limestone, Maine, USA. In support of the pilot study, borehole radar reflection logs were collected three times (before, during, and near the end of steam injection) using broadband 100 MHz electric dipole antennas. Numerical modelling was performed to predict the effect of heating on radar-frequency electromagnetic (EM) wave velocity, attenuation, and fracture reflectivity. The modelling results indicate that EM wave velocity and attenuation change substantially if heating increases the electrical conductivity of the limestone matrix. Furthermore, the net effect of heat-induced variations in fracture-fluid dielectric properties on average medium velocity is insignificant because the expected total fracture porosity is low. In contrast, changes in fracture fluid electrical conductivity can have a significant effect on EM wave attenuation and fracture reflectivity. Total replacement of water by steam in a fracture decreases fracture reflectivity of a factor of 10 and induces a change in reflected wave polarity. Based on the numerical modelling results, a reflection amplitude analysis method was developed to delineate fractures where steam has displaced water. Radar reflection logs collected during the three acquisition periods were analysed in the frequency domain to determine if steam had replaced water in the fractures (after normalizing the logs to compensate for differences in antenna performance between logging runs). Analysis of the radar reflection logs from a borehole where the temperature increased substantially during the steam injection experiment shows an increase in attenuation and a decrease in reflectivity in the vicinity of the borehole. Results of applying the reflection amplitude analysis method developed for this study indicate that steam did not totally replace the water in most of the fractures. The observed decreases in reflectivity were consistent with an increase in fracture-water temperature, rather than the presence of steam. A limiting assumption of the reflection amplitude analysis method is the requirement for complete displacement of water in a fracture by steam. ?? 2006 Elsevier B.V. All rights reserved.

5 CFR 430.405 - Procedures for certifying agency appraisal systems.

Code of Federal Regulations, 2011 CFR

2011-01-01

... supervise to ensure that they reflect distinctions in individual and organizational performance, as... SERVICE REGULATIONS PERFORMANCE MANAGEMENT Performance Appraisal Certification for Pay Purposes § 430.405... of the appraisal system(s) to be certified, including— (i) Organizational and employee coverage...

Problems in air traffic management. VII., Job training performance of air traffic control specialists - measurement, structure, and prediction.

DOT National Transportation Integrated Search

1965-07-01

A statistical study of training- and job-performance measures of several hundred Air Traffic Control Specialists (ATCS) representing Enroute, Terminal, and Flight Service Station specialties revealed that training-performance measures reflected: : 1....

Point coordinates extraction from localized hyperbolic reflections in GPR data

NASA Astrophysics Data System (ADS)

Ristić, Aleksandar; Bugarinović, Željko; Vrtunski, Milan; Govedarica, Miro

2017-09-01

In this paper, we propose an automated detection algorithm for the localization of apexes and points on the prongs of hyperbolic reflection incurred as a result of GPR scanning technology. The objects of interest encompass cylindrical underground utilities that have a distinctive form of hyperbolic reflection in radargram. Algorithm involves application of trained neural network to analyze radargram in the form of raster image, resulting with extracted segments of interest that contain hyperbolic reflections. This significantly reduces the amount of data for further analysis. Extracted segments represent the zone for localization of apices. This is followed by extraction of points on prongs of hyperbolic reflections which is carried out until stopping criterion is satisfied, regardless the borders of segment of interest. In final step a classification of false hyperbolic reflections caused by the constructive interference and their removal is done. The algorithm is implemented in MATLAB environment. There are several advantages of the proposed algorithm. It can successfully recognize true hyperbolic reflections in radargram images and extracts coordinates, with very low rate of false detections and without prior knowledge about the number of hyperbolic reflections or buried utilities. It can be applied to radargrams containing single and multiple hyperbolic reflections, intersected, distorted, as well as incomplete (asymmetric) hyperbolic reflections, all in the presence of higher level of noise. Special feature of algorithm is developed procedure for analysis and removal of false hyperbolic reflections generated by the constructive interference from reflectors associated with the utilities. Algorithm was tested on a number of synthetic and radargram acquired in the field survey. To illustrate the performances of the proposed algorithm, we present the characteristics of the algorithm through five representative radargrams obtained in real conditions. In these examples we present different acquisition scenarios by varying the number of buried objects, their disposition, size, and level of noise. Example with highest complexity was tested also as a synthetic radargram generated by gprMax. Processing time in examples with one or two hyperbolic reflections is from 0.1 to 0.3 s, while for the most complex examples it is from 2.2 to 4.9 s. In general, the obtained experimental results show that the proposed algorithm exhibits promising performances both in terms of utility detection and processing speed of the algorithm.

Oscillatory theta activity during memory formation and its impact on overnight consolidation: a missing link?

PubMed

Heib, Dominik P J; Hoedlmoser, Kerstin; Anderer, Peter; Gruber, Georg; Zeitlhofer, Josef; Schabus, Manuel

2015-08-01

Sleep has been shown to promote memory consolidation driven by certain oscillatory patterns, such as sleep spindles. However, sleep does not consolidate all newly encoded information uniformly but rather "selects" certain memories for consolidation. It is assumed that such selection depends on salience tags attached to the new memories before sleep. However, little is known about the underlying neuronal processes reflecting presleep memory tagging. The current study sought to address the question of whether event-related changes in spectral theta power (theta ERSP) during presleep memory formation could reflect memory tagging that influences subsequent consolidation during sleep. Twenty-four participants memorized 160 word pairs before sleep; in a separate laboratory visit, they performed a nonlearning control task. Memory performance was tested twice, directly before and after 8 hr of sleep. Results indicate that participants who improved their memory performance overnight displayed stronger theta ERSP during the memory task in comparison with the control task. They also displayed stronger memory task-related increases in fast sleep spindle activity. Furthermore, presleep theta activity was directly linked to fast sleep spindle activity, indicating that processes during memory formation might indeed reflect memory tagging that influences subsequent consolidation during sleep. Interestingly, our results further indicate that the suggested relation between sleep spindles and overnight performance change is not as direct as once believed. Rather, it appears to be mediated by processes beginning during presleep memory formation. We conclude that theta ERSP during presleep memory formation reflects cortico-hippocampal interactions that lead to a better long-term accessibility by tagging memories for sleep spindle-related reprocessing.

Improved classification and visualization of healthy and pathological hard dental tissues by modeling specular reflections in NIR hyperspectral images

NASA Astrophysics Data System (ADS)

Usenik, Peter; Bürmen, Miran; Fidler, Aleš; Pernuš, Franjo; Likar, Boštjan

2012-03-01

Despite major improvements in dental healthcare and technology, dental caries remains one of the most prevalent chronic diseases of modern society. The initial stages of dental caries are characterized by demineralization of enamel crystals, commonly known as white spots, which are difficult to diagnose. Near-infrared (NIR) hyperspectral imaging is a new promising technique for early detection of demineralization which can classify healthy and pathological dental tissues. However, due to non-ideal illumination of the tooth surface the hyperspectral images can exhibit specular reflections, in particular around the edges and the ridges of the teeth. These reflections significantly affect the performance of automated classification and visualization methods. Cross polarized imaging setup can effectively remove the specular reflections, however is due to the complexity and other imaging setup limitations not always possible. In this paper, we propose an alternative approach based on modeling the specular reflections of hard dental tissues, which significantly improves the classification accuracy in the presence of specular reflections. The method was evaluated on five extracted human teeth with corresponding gold standard for 6 different healthy and pathological hard dental tissues including enamel, dentin, calculus, dentin caries, enamel caries and demineralized regions. Principal component analysis (PCA) was used for multivariate local modeling of healthy and pathological dental tissues. The classification was performed by employing multiple discriminant analysis. Based on the obtained results we believe the proposed method can be considered as an effective alternative to the complex cross polarized imaging setups.

Mathematical anxiety is linked to reduced cognitive reflection: a potential road from discomfort in the mathematics classroom to susceptibility to biases.

PubMed

Morsanyi, Kinga; Busdraghi, Chiara; Primi, Caterina

2014-09-01

When asked to solve mathematical problems, some people experience anxiety and threat, which can lead to impaired mathematical performance (Curr Dir Psychol Sci 11:181-185, 2002). The present studies investigated the link between mathematical anxiety and performance on the cognitive reflection test (CRT; J Econ Perspect 19:25-42, 2005). The CRT is a measure of a person's ability to resist intuitive response tendencies, and it correlates strongly with important real-life outcomes, such as time preferences, risk-taking, and rational thinking. In Experiments 1 and 2 the relationships between maths anxiety, mathematical knowledge/mathematical achievement, test anxiety and cognitive reflection were analysed using mediation analyses. Experiment 3 included a manipulation of working memory load. The effects of anxiety and working memory load were analysed using ANOVAs. Our experiments with university students (Experiments 1 and 3) and secondary school students (Experiment 2) demonstrated that mathematical anxiety was a significant predictor of cognitive reflection, even after controlling for the effects of general mathematical knowledge (in Experiment 1), school mathematical achievement (in Experiment 2) and test anxiety (in Experiments 1-3). Furthermore, Experiment 3 showed that mathematical anxiety and burdening working memory resources with a secondary task had similar effects on cognitive reflection. Given earlier findings that showed a close link between cognitive reflection, unbiased decisions and rationality, our results suggest that mathematical anxiety might be negatively related to individuals' ability to make advantageous choices and good decisions.

Personal sound zone reproduction with room reflections

NASA Astrophysics Data System (ADS)

Olik, Marek

Loudspeaker-based sound systems, capable of a convincing reproduction of different audio streams to listeners in the same acoustic enclosure, are a convenient alternative to headphones. Such systems aim to generate "sound zones" in which target sound programmes are to be reproduced with minimum interference from any alternative programmes. This can be achieved with appropriate filtering of the source (loudspeaker) signals, so that the target sound's energy is directed to the chosen zone while being attenuated elsewhere. The existing methods are unable to produce the required sound energy ratio (acoustic contrast) between the zones with a small number of sources when strong room reflections are present. Optimization of parameters is therefore required for systems with practical limitations to improve their performance in reflective acoustic environments. One important parameter is positioning of sources with respect to the zones and room boundaries. The first contribution of this thesis is a comparison of the key sound zoning methods implemented on compact and distributed geometrical source arrangements. The study presents previously unpublished detailed evaluation and ranking of such arrangements for systems with a limited number of sources in a reflective acoustic environment similar to a domestic room. Motivated by the requirement to investigate the relationship between source positioning and performance in detail, the central contribution of this thesis is a study on optimizing source arrangements when strong individual room reflections occur. Small sound zone systems are studied analytically and numerically to reveal relationships between the geometry of source arrays and performance in terms of acoustic contrast and array effort (related to system efficiency). Three novel source position optimization techniques are proposed to increase the contrast, and geometrical means of reducing the effort are determined. Contrary to previously published case studies, this work presents a systematic examination of the key problem of first order reflections and proposes general optimization techniques, thus forming an important contribution. The remaining contribution considers evaluation and comparison of the proposed techniques with two alternative approaches to sound zone generation under reflective conditions: acoustic contrast control (ACC) combined with anechoic source optimization and sound power minimization (SPM). The study provides a ranking of the examined approaches which could serve as a guideline for method selection for rooms with strong individual reflections.

The Reliability and Validity of Protocols for the Assessment of Endurance Sports Performance: An Updated Review

ERIC Educational Resources Information Center

Stevens, Christopher John; Dascombe, Ben James

2015-01-01

Sports performance testing is one of the most common and important measures used in sport science. Performance testing protocols must have high reliability to ensure any changes are not due to measurement error or inter-individual differences. High validity is also important to ensure test performance reflects true performance. Time-trial…

Action and familiarity effects on self and other expert musicians’ Laban effort-shape analyses of expressive bodily behaviors in instrumental music performance: a case study approach

PubMed Central

Broughton, Mary C.; Davidson, Jane W.

2014-01-01

Self-reflective performance review and expert evaluation are features of Western music performance practice. While music is usually the focus, visual information provided by performing musicians’ expressive bodily behaviors communicates expressiveness to musically trained and untrained observers. Yet, within a seemingly homogenous group, such as one of musically trained individuals, diversity of experience exists. Individual differences potentially affect perception of the subtleties of expressive performance, and performers’ effective communication of their expressive intentions. This study aimed to compare self- and other expert musicians’ perception of expressive bodily behaviors observed in marimba performance. We hypothesized that analyses of expressive bodily behaviors differ between expert musicians according to their specialist motor expertise and familiarity with the music. Two professional percussionists and experienced marimba players, and one professional classical singer took part in the study. Participants independently conducted Laban effort-shape analysis – proposing that intentions manifest in bodily activity are understood through shared embodied processes – of a marimbists’ expressive bodily behaviors in an audio-visual performance recording. For one percussionist, this was a self-reflective analysis. The work was unfamiliar to the other percussionist and singer. Perception of the performer’s expressive bodily behaviors appeared to differ according to participants’ individual instrumental or vocal motor expertise, and familiarity with the music. Furthermore, individual type of motor experience appeared to direct participants’ attention in approaching the analyses. Findings support forward and inverse perception–action models, and embodied cognitive theory. Implications offer scientific rigor and artistic interest for how performance practitioners can reflectively analyze performance to improve expressive communication. PMID:25400601

Pondering practice: Enhancing the art of reflection.

PubMed

Hayes, Carolyn; Jackson, Debra; Davidson, Patricia M; Daly, John; Power, Tamara

2018-01-01

The aim of this study was to describe the effect that immersive simulation experiences and guided reflection can have on the undergraduate nurses' understanding of how stressful environments impact their emotions, performance and ability to implement safe administration of medications. Patient safety can be jeopardised if nurses are unsure of how to appropriately manage and respond to interruptions. Medication administration errors are a major patient safety issue and often occur as a consequence of ineffective interruption management. The skills associated with medication administration are most often taught to, and performed by, undergraduate nurses in a controlled environment. However, the clinical environment in which nurses are expected to administer medications is often highly stressed and nurses are frequently interrupted. This study used role-play simulation and written reflections to facilitate deeper levels of student self-awareness. A qualitative approach was taken to explore students' understanding of the effects of interruptions on their ability to undertake safe medication administration. Convenience sampling of second-year undergraduate nursing students enrolled in a medical-surgical subject was used in this study. Data were obtained from 451:528 (85.42%) of those students and analysed using thematic analysis. Students reported increasing consciousness and the importance of reflection for evaluating performance and gaining self-awareness. They described self-awareness, effective communication, compassion and empathy as significant factors in facilitating self-efficacy and improved patient care outcomes. Following a role-play simulation experience, student nurses reported new knowledge and skill acquisition related to patient safety, and new awareness of the need for empathetic and compassionate care during medication administration. Practicing medication administration in realistic settings adds to current strategies that aim to reduce medication errors by allowing students to reflect on and in practice and develop strategies to ensure patient safety. Experiencing clinical scenarios within the safety of simulated environments, offers undergraduate student nurses an opportunity to reflect on practice to provide safer, more empathetic and compassionate care for patients in the future. © 2017 John Wiley & Sons Ltd.

Can exposure to prenatal sex hormones (2D:4D) predict cognitive reflection?

PubMed

Bosch-Domènech, Antoni; Brañas-Garza, Pablo; Espín, Antonio M

2014-05-01

The Cognitive Reflection Test (CRT) is a test introduced by Frederick (2005). The task is designed to measure the tendency to override an intuitive response that is incorrect and to engage in further reflection that leads to the correct response. The consistent sex differences in CRT performance may suggest a role for prenatal sex hormones. A now widely studied putative marker for relative prenatal testosterone is the second-to-fourth digit ratio (2D:4D). This paper tests to what extent 2D:4D, as a proxy for the prenatal ratio of testosterone/estrogens, can predict CRT scores in a sample of 623 students. After controlling for sex, we observe that a lower 2D:4D (reflecting a relative higher exposure to testosterone) is significantly associated with a higher number of correct answers. The result holds for both hands' 2D:4Ds. In addition, the effect appears to be stronger for females than for males. We also control for patience and math proficiency, which are significantly related to performance in the CRT. But the effect of 2D:4D on performance in CRT is not reduced with these controls, implying that these variables are not mediating the relationship between digit ratio and CRT. Copyright © 2014 The Authors. Published by Elsevier Ltd. All rights reserved.

Electromagnetic Design and Performance of a Conical Microwave Blackbody Target for Radiometer Calibration

NASA Astrophysics Data System (ADS)

Houtz, Derek A.; Emery, William; Gu, Dazhen; Jacob, Karl; Murk, Axel; Walker, David K.; Wylde, Richard J.

2017-08-01

A conical cavity has been designed and fabricated for use as a broadband passive microwave calibration source, or blackbody, at the National Institute of Standards and Technology. The blackbody will be used as a national primary standard for brightness temperature and will allow for the prelaunch calibration of spaceborne radiometers and calibration of ground-based systems to provide traceability among radiometric data. The conical geometry provides performance independent of polarization, minimizing reflections, and standing waves, thus having a high microwave emissivity. The conical blackbody has advantages over typical pyramidal array geometries, including reduced temperature gradients and excellent broadband electromagnetic performance over more than a frequency decade. The blackbody is designed for use between 18 and 230 GHz, at temperatures between 80 and 350 K, and is vacuum compatible. To approximate theoretical blackbody behavior, the design maximizes emissivity and thus minimizes reflectivity. A newly developed microwave absorber is demonstrated that uses cryogenically compatible, thermally conductive two-part epoxy with magnetic carbonyl iron (CBI) powder loading. We measured the complex permittivity and permeability properties for different CBI-loading percentages; the conical absorber is then designed and optimized with geometric optics and finite-element modeling, and finally, the reflectivity of the resulting fabricated structure is measured. We demonstrated normal incidence reflectivity considerably below -40 dB at all relevant remote sensing frequencies.

Metacognition and schizophrenia: the capacity for self-reflectivity as a predictor for prospective assessments of work performance over six months.

PubMed

Lysaker, Paul H; Dimaggio, Giancarlo; Carcione, Antonino; Procacci, Michele; Buck, Kelly D; Davis, Louanne W; Nicolò, Giuseppe

2010-09-01

Research has indicated that many with schizophrenia experience deficits in metacognitive capacity, defined as impairments in the ability to think about thinking. These difficulties are related to, but not reducible to symptoms and have been hypothesized to function as an independent impediment to psychosocial function. To explore the possibility that deficits in one domain of metacognition, self-reflectivity, are a barrier to effective work function, 56 participants with schizophrenia were categorized into three groups according to their capacity for self reflection based on an interview conducted prior to accepting a job placement. Blind ratings of work performance of these three groups over the next six months were then compared. Results of repeated measures ANOVA revealed that the group rated as having the highest level of metacognition, that is, able to see that their conclusions are subjective and fallible, had higher ratings of work performance over time than groups with medium and low levels of self reflectivity. These findings were found to persist even when impairment on a test of executive function was controlled for statistically. Results are interpreted as consistent with emerging models that deficits in metacognition may be key features of severe mental illness which affect function. Clinical and theoretic implications are discussed. (c) 2010 Elsevier B.V. All rights reserved.

Insight in Schizophrenia: Involvement of Self-Reflection Networks?

PubMed Central

de Vos, Annerieke E.

2013-01-01

Background: Impaired insight is a common feature in psychosis and an important predictor of variables such as functional outcome, prognosis, and treatment adherence. A cognitive process that may underlie insight in psychosis is self-reflection, or the conscious evaluation of one’s traits and characteristics. The current study aims to investigate the neural correlates of self-reflective processing and its relationship with insight in schizophrenia. Methods: Forty-seven schizophrenia patients and 21 healthy controls performed a self-reflection task in a functional magnetic resonance imaging (fMRI) scanner. The tasks comprised a self-reflection, close other-reflection, and a semantic (baseline) condition. Insight scores were obtained with the Schedule of Assessment of Insight Expanded. In addition, cognitive insight scores were obtained (Beck Cognitive Insight Scale [BCIS]). Results: Schizophrenia patients demonstrated less activation in the posterior cingulate cortex in the self- and other-reflection conditions and less activation in the precuneus in the other-reflection condition compared with healthy controls. Better insight was associated with greater response in the inferior frontal gyrus, anterior insula, and inferior parietal lobule during self-reflection. In addition, better cognitive insight was associated with higher activation in ventromedial prefrontal cortex during self-reflection. Conclusion: In the current study, evidence for a relationship between self-reflection and insight in patients with schizophrenia was found in brain areas related to self-reflection, self/other distinction and source attribution. The findings support the rationale for a treatment that is currently under evaluation, which attempts to increase insight by enhancing self-reflection. PMID:23104865

Insight in schizophrenia: involvement of self-reflection networks?

PubMed

van der Meer, Lisette; de Vos, Annerieke E; Stiekema, Annemarie P M; Pijnenborg, Gerdina H M; van Tol, Marie-José; Nolen, Willem A; David, Anthony S; Aleman, André

2013-11-01

Impaired insight is a common feature in psychosis and an important predictor of variables such as functional outcome, prognosis, and treatment adherence. A cognitive process that may underlie insight in psychosis is self-reflection, or the conscious evaluation of one's traits and characteristics. The current study aims to investigate the neural correlates of self-reflective processing and its relationship with insight in schizophrenia. Forty-seven schizophrenia patients and 21 healthy controls performed a self-reflection task in a functional magnetic resonance imaging (fMRI) scanner. The tasks comprised a self-reflection, close other-reflection, and a semantic (baseline) condition. Insight scores were obtained with the Schedule of Assessment of Insight Expanded. In addition, cognitive insight scores were obtained (Beck Cognitive Insight Scale [BCIS]). Schizophrenia patients demonstrated less activation in the posterior cingulate cortex in the self- and other-reflection conditions and less activation in the precuneus in the other-reflection condition compared with healthy controls. Better insight was associated with greater response in the inferior frontal gyrus, anterior insula, and inferior parietal lobule during self-reflection. In addition, better cognitive insight was associated with higher activation in ventromedial prefrontal cortex during self-reflection. In the current study, evidence for a relationship between self-reflection and insight in patients with schizophrenia was found in brain areas related to self-reflection, self/other distinction and source attribution. The findings support the rationale for a treatment that is currently under evaluation, which attempts to increase insight by enhancing self-reflection.

Primacy Performance of Normal and Retarded Children: Stimulus Familiarity or Spatial Memory?

ERIC Educational Resources Information Center

Swanson, Lee

1978-01-01

Explores the effect of stimulus familiarity on the spatial primacy performance of normal and retarded children. Assumes that serial recall tasks reflect spatial memory rather than verbal rehearsal. (BD)

Performance evaluation of automated segmentation software on optical coherence tomography volume data

PubMed Central

Tian, Jing; Varga, Boglarka; Tatrai, Erika; Fanni, Palya; Somfai, Gabor Mark; Smiddy, William E.

2016-01-01

Over the past two decades a significant number of OCT segmentation approaches have been proposed in the literature. Each methodology has been conceived for and/or evaluated using specific datasets that do not reflect the complexities of the majority of widely available retinal features observed in clinical settings. In addition, there does not exist an appropriate OCT dataset with ground truth that reflects the realities of everyday retinal features observed in clinical settings. While the need for unbiased performance evaluation of automated segmentation algorithms is obvious, the validation process of segmentation algorithms have been usually performed by comparing with manual labelings from each study and there has been a lack of common ground truth. Therefore, a performance comparison of different algorithms using the same ground truth has never been performed. This paper reviews research-oriented tools for automated segmentation of the retinal tissue on OCT images. It also evaluates and compares the performance of these software tools with a common ground truth. PMID:27159849

Measuring comparative hospital performance.

PubMed

Griffith, John R; Alexander, Jeffrey A; Jelinek, Richard C

2002-01-01

Leading healthcare provider organizations now use a "balanced scorecard" of performance measures, expanding information reviewed at the governance level to include financial, customer, and internal performance information, as well as providing an opportunity to learn and grow to provide better strategic guidance. The approach, successfully used by other industries, uses competitor data and benchmarks to identify opportunities for improved mission achievement. This article evaluates one set of nine multidimensional hospital performance measures derived from Medicare reports (cash flow, asset turnover, mortality, complications, length of inpatient stay, cost per case, occupancy, change in occupancy, and percent of revenue from outpatient care). The study examines the content validity, reliability and sensitivity, validity of comparison, and independence and concludes that seven of the nine measures (all but the two occupancy measures) represent a potentially useful set for evaluating most U.S. hospitals. This set reflects correctable differences in performance between hospitals serving similar populations, that is, the measures reflect relative performance and identify opportunities to make the organization more successful.

Younger and older adults' perception of the Wundt-Hering illusion as a function of display illumination and reflectance contrast.

PubMed

Astor-Stetson, E; Lane, S

1991-08-01

Reflectance contrast (i.e., black as compared to grey figures on white ground) and display illumination were manipulated to vary the brightness contrast of Wundt-Hering figures. 16 college students and 16 older adults were presented with high, medium, and low reflectance contrast figures. For half the participants, display illumination was manipulated by covering the figures with a .5 yellow neutral density filter. Magnitude of the illusion increased significantly with increased reflectance contrast for college students, and college students were significantly more susceptible to the high contrast figures than were older adults. Display illumination had no effect on the performance of either group.

Self-regulated learning and academic performance in medical education.

PubMed

Lucieer, Susanna M; Jonker, Laura; Visscher, Chris; Rikers, Remy M J P; Themmen, Axel P N

2016-06-01

Medical schools aim to graduate medical doctors who are able to self-regulate their learning. It is therefore important to investigate whether medical students' self-regulated learning skills change during medical school. In addition, since these skills are expected to be helpful to learn more effectively, it is of interest to investigate whether these skills are related to academic performance. In a cross-sectional design, the Self-Regulation of Learning Self-Report Scale (SRL-SRS) was used to investigate the change in students' self-regulated learning skills. First and third-year students (N = 949, 81.7%) SRL-SRS scores were compared with ANOVA. The relation with academic performance was investigated with multinomial regression analysis. Only one of the six skills, reflection, significantly, but positively, changed during medical school. In addition, a small, but positive relation of monitoring, reflection, and effort with first-year GPA was found, while only effort was related to third-year GPA. The change in self-regulated learning skills is minor as only the level of reflection differs between the first and third year. In addition, the relation between self-regulated learning skills and academic performance is limited. Medical schools are therefore encouraged to re-examine the curriculum and methods they use to enhance their students' self-regulated learning skills. Future research is required to understand the limited impact on performance.

Non-Simultaneous Relative Importance-Performance Analysis: Meta-Results from 80 College Choice Surveys with 55,276 Respondents.

ERIC Educational Resources Information Center

Chapman, Randall G.

1993-01-01

A study investigated the utility of importance-performance analysis, a marketing tool for assessing marketing position and performance, in learning how college applicants perceive their chosen college in comparison with others. Findings reflect the complexity of student decisions and suggest the "average" college performs above average…

Distance, Online and Campus Higher Education: Reflections on Learning Outcomes

ERIC Educational Resources Information Center

McPhee, Iain; Soderstrom, Tor

2012-01-01

Purpose: The purpose of this paper is to discuss performance in postgraduate education in Sweden and Scotland. Drawing on two cases, the paper considers three themes: differences in students' performance by study mode, differences in students' performance by length of study, and finally comparing performance by study mode between modules in…

Development of reflective optical systems for XUV projection lithography

NASA Astrophysics Data System (ADS)

Viswanathan, V. K.; Newnam, B. E.

We describe two full-field reflective reduction systems (1 and 6.25 sq cm image area) and one scanning system (25 mm x scan length image size) that meet the performance requirements for 0.1-micron resolution projection lithography using extreme-ultraviolet (XUV) wavelengths from 10 to 15 nm. These systems consist of two centered, symmetric, annular aspheric mirrors with 35 to 40 percent central obscuration, providing a reduction ratio of 3.3 x. Outstanding features include the remarkably low distortion (less than or = 10 nm) over the entire image field and the comparatively liberal tolerances on the mirror radii and alignment. While optimized annular illumination can improve the performance, the required performance can be met with full illumination, thereby allowing a simpler system design.

Proven high-performance display solution

NASA Astrophysics Data System (ADS)

Johnson, Rick J.; Shaw, James E.; Mosier, Don; Liss, Raymond L.; Prouty, Todd D.; Davis, Josh; Marzen, Vincent P.; Deloy, Christian T.

2002-08-01

Rockwell Collins serves both the military and the commercial segments by exploiting the common elements of these applications. Rockwell Collins has created a liquid crystal display family capable of 100:1 contrast ratio, 40:1 high ambient contrast, 0.25% specular reflectance, 0.1% diffuse reflectance, enhanced color stability over +/- 55H, 0-30V field of view, 300 fL with 10K:1 dimming range, color NVIS B compliance while exceeding environmental performance requirements though ruggedization. In order to meet the full range of display requirements at a system level, all the components must be understood and managed to meet the end solution of the final system. This paper details Rockwell Collins' optical performance using an avionics grade panel, third generation custom compensation, and solid state backlight.

Ground truth data for test sites (SL-3). [solar radiation and thermal radiation brightness temperature measurements

NASA Technical Reports Server (NTRS)

1974-01-01

Field measurements performed simultaneously with Skylab overpasses in order to provide comparative calibration and performance evaluation measurements for the EREP sensors are presented. The solar radiation region from 400 to 1300 nanometers and the thermal radiation region from 8 to 14 micrometer region were investigated. The measurements of direct solar radiation were analyzed for atmospheric optical depth; the total and reflected solar radiation were analyzed for target reflectivity. These analyses were used in conjunction with a radiative transfer computer program in order to calculate the amount and spectral distribution of solar radiation at the apertures of the EREP sensors. The instrumentation and techniques employed, calibrations and analyses performed, and results obtained are discussed.

Improved optical design of nontracking concentrators

NASA Astrophysics Data System (ADS)

Kwan, B. M.; Bannerot, R. B.

1984-08-01

Optical designs based on a two reflections or less criterion have been developed for one and two-facet trapezoidal concentrators. Collector designs resulting from this criterion have been evaluated with the aid of a ray-trace computer simulation which includes the effects of nonideal reflectors. Results indicate a marked increase in performance, particularly for the one-facet designs, as compared to the collectors previously designed with the one reflection or less criterion. A significant result is that when a proper accounting is made for the actual acceptance angle for the concentrators, the performances of the optimal one and two-facet designs become nearly identical, indicating that the previously held contention that improved performance could be achieved with multifaceted reflectors (geometrically approaching the compound parabolic shape) may be incorrect.

Optimization of MLS receivers for multipath environments

NASA Technical Reports Server (NTRS)

Mcalpine, G. A.; Irwin, S. H.; NELSON; Roleyni, G.

1977-01-01

Optimal design studies of MLS angle-receivers and a theoretical design-study of MLS DME-receivers are reported. The angle-receiver results include an integration of the scan data processor and tracking filter components of the optimal receiver into a unified structure. An extensive simulation study comparing the performance of the optimal and threshold receivers in a wide variety of representative dynamical interference environments was made. The optimal receiver was generally superior. A simulation of the performance of the threshold and delay-and-compare receivers in various signal environments was performed. An analysis of combined errors due to lateral reflections from vertical structures with small differential path delays, specular ground reflections with neglible differential path delays, and thermal noise in the receivers is provided.

Atomic force microscopy characterization of Zerodur mirror substrates for the extreme ultraviolet telescopes aboard NASA's Solar Dynamics Observatory.

PubMed

Soufli, Regina; Baker, Sherry L; Windt, David L; Gullikson, Eric M; Robinson, Jeff C; Podgorski, William A; Golub, Leon

2007-06-01

The high-spatial frequency roughness of a mirror operating at extreme ultraviolet (EUV) wavelengths is crucial for the reflective performance and is subject to very stringent specifications. To understand and predict mirror performance, precision metrology is required for measuring the surface roughness. Zerodur mirror substrates made by two different polishing vendors for a suite of EUV telescopes for solar physics were characterized by atomic force microscopy (AFM). The AFM measurements revealed features in the topography of each substrate that are associated with specific polishing techniques. Theoretical predictions of the mirror performance based on the AFM-measured high-spatial-frequency roughness are in good agreement with EUV reflectance measurements of the mirrors after multilayer coating.

Method to adjust multilayer film stress induced deformation of optics

DOEpatents

Spiller, Eberhard A.; Mirkarimi, Paul B.; Montcalm, Claude; Bajt, Sasa; Folta, James A.

2000-01-01

Stress compensating systems that reduces/compensates stress in a multilayer without loss in reflectivity, while reducing total film thickness compared to the earlier buffer-layer approach. The stress free multilayer systems contain multilayer systems with two different material combinations of opposite stress, where both systems give good reflectivity at the design wavelengths. The main advantage of the multilayer system design is that stress reduction does not require the deposition of any additional layers, as in the buffer layer approach. If the optical performance of the two systems at the design wavelength differ, the system with the poorer performance is deposited first, and then the system with better performance last, thus forming the top of the multilayer system. The components for the stress reducing layer are chosen among materials that have opposite stress to that of the preferred multilayer reflecting stack and simultaneously have optical constants that allow one to get good reflectivity at the design wavelength. For a wavelength of 13.4 nm, the wavelength presently used for extreme ultraviolet (EUV) lithography, Si and Be have practically the same optical constants, but the Mo/Si multilayer has opposite stress than the Mo/Be multilayer. Multilayer systems of these materials have practically identical reflectivity curves. For example, stress free multilayers can be formed on a substrate using Mo/Be multilayers in the bottom of the stack and Mo/Si multilayers at the top of the stack, with the switch-over point selected to obtain zero stress. In this multilayer system, the switch-over point is at about the half point of the total thickness of the stack, and for the Mo/Be--Mo/Si system, there may be 25 deposition periods Mo/Be to 20 deposition periods Mo/Si.

Bright color optical switching device by polymer network liquid crystal with a specular reflector.

PubMed

Lee, Gae Hwang; Hwang, Kyu Young; Jang, Jae Eun; Jin, Yong Wan; Lee, Sang Yoon; Jung, Jae Eun

2011-07-04

The color optical switching device by polymer network liquid crystal (PNLC) with color filter on a specular reflector shows excellent performance; white reflectance of 22%, color gamut of 32%, and contrast ratio up to 50:1 in reflective mode measurement. The view-angle dependence of the reflectance can be adjusted by changing the PNLC thickness. The color chromaticity shown by the device is close to the limit value of color filters, and its value nearly remains with respect to the operating voltage. These optical properties of the device can be explained from the prediction based on multiple interactions between the light and the droplets of liquid crystal. The high reflectance, vivid color image, and moderate responds time allow the PNLC device to drive good color moving image. It can widely extend the applications of the reflective device.

Permittivity of water at millimeter wave-lengths

NASA Technical Reports Server (NTRS)

Blue, M. D.

1976-01-01

Work performed on the permittivity of seawater and ice at 100 GHz was described. Measurements on water covered the temperature range from 0 to 50 C, while the measurements on ice were taken near - 10 C. In addition, a small number of measurements were made on the reflectivity of absorber materials used in a previous program on research in millimeter wave techniques. Normal incidence reflectivity was measured, and the result was used to obtain the index of refraction. For the case of normal incidence, reflectivity at a fixed temperature was reproducible to 1% for values near 40%. For reflectivity measurements on ice, the lack of attenuation leads to reflection from the back surface of the sample; this complication was circumvented by using a wedge shaped sample and freezing the water in a container lined with absorber material.

Properties of light reflected from road signs in active imaging.

PubMed

Halstuch, Aviran; Yitzhaky, Yitzhak

2008-08-01

Night vision systems in vehicles are a new emerging technology. A crucial problem in active (laser-based) systems is distortion of images by saturation and blooming due to strong retroreflections from road signs. We quantify this phenomenon. We measure the Mueller matrices and the polarization state of the reflected light from three different types of road sign commonly used. Measurements of the reflected intensity are also taken with respect to the angle of reflection. We find that different types of sign have different reflection properties. It is concluded that the optimal solution for attenuating the retroreflected intensity is using a linear polarized light source and a linear polarizer with perpendicular orientation (with regard to the source) at the detector. Unfortunately, while this solution performs well for two types of road sign, it is less efficient for the third sign type.

Spontaneous Self-Distancing and Adaptive Self-Reflection Across Adolescence.

PubMed

White, Rachel E; Kross, Ethan; Duckworth, Angela L

2015-07-01

Experiments performed primarily with adults show that self-distancing facilitates adaptive self-reflection. However, no research has investigated whether adolescents spontaneously engage in this process or whether doing so is linked to adaptive outcomes. In this study, 226 African American adolescents, aged 11-20, reflected on an anger-related interpersonal experience. As expected, spontaneous self-distancing during reflection predicted lower levels of emotional reactivity by leading adolescents to reconstrue (rather than recount) their experience and blame their partner less. Moreover, the inverse relation between self-distancing and emotional reactivity strengthened with age. These findings highlight the role that self-distancing plays in fostering adaptive self-reflection in adolescence, and begin to elucidate the role that development plays in enhancing the benefits of engaging in this process. © 2015 The Authors. Child Development © 2015 Society for Research in Child Development, Inc.

Testing reflective insulation for improvement of buildings energy efficiency

NASA Astrophysics Data System (ADS)

Vrachopoulos, Michalis Gr.; Koukou, Maria K.; Stavlas, Dimitris G.; Stamatopoulos, Vasilis N.; Gonidis, Achilleas F.; Kravvaritis, Eleftherios D.

2012-03-01

Reflective insulation stands as an alternative to common building materials used to reduce a building's heating and cooling loads. In this work, an experimental prototype chamber facility has been designed and constructed at the campus of the Technological Educational Institution of Halkida, located in an area of climatic zone B in Greece, aiming to the evaluation of reflective insulation's performance. Reflective insulation is a part of the test room wall construction, specifically, heat insulation material of the vertical wall construction all directions (North, South, East, West), and temperature and water proofing element of the roof. Measurements were obtained for both winter and summer periods. Results indicate that the existence of reflective insulation during summer period averts the overheating at the interior of the experimental chamber, while during winter the heat is retained in the chamber.

[The ethical reflection approach in decision-making processes in health institutes].

PubMed

Gruat, Renaud

2015-12-01

Except in the specific case of end-of-life care, the law says nothing about the way in which health professionals must carry out ethical reflection regarding the treatment of their patients. A problem-solving methodology called the "ethical reflection approach" performed over several stages can be used. The decision-making process involves the whole team and draws on the ability of each caregiver to put forward a reasoned argument, in the interest of the patient. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Optical coatings for laser fusion applications

NASA Astrophysics Data System (ADS)

Lowdermilk, W. H.; Milam, D.; Rainer, F.

1980-04-01

Lasers for fusion experiments use thin-film dielectric coatings for reflecting antireflecting and polarizing surface elements. Coatings are most important to the Nd:glass laser application. The most important requirements of these coatings are accuracy of the average value of reflectance and transmission, uniformity of amplitude and phase front of the reflected or transmitted light, and laser damage threshold. Damage resistance strongly affects the laser's design and performance. The success of advanced lasers for future experiments and for reactor applications requires significant developments in damage resistant coatings for ultraviolet laser radiation.

Impact of input FBG reflectivity and forward pump power on RIN transfer in ultralong Raman laser amplifiers.

PubMed

Rizzelli, Giuseppe; Iqbal, Md Asif; Gallazzi, Francesca; Rosa, Paweł; Tan, Mingming; Ania-Castañón, Juan Diego; Krzczanowicz, Lukasz; Corredera, Pedro; Phillips, Ian; Forysiak, Wladek; Harper, Paul

2016-12-12

Relative intensity noise transfer from the pump to the signal in 2nd-order ultra-long Raman laser amplifiers for telecommunications is characterized numerically and experimentally. Our results showcase the need for careful adjustment of the front FBG reflectivity and the relative contribution of forward pump power, and their impact on performance. Finally, our analysis is verified through a 10 × 30 GBaud DP-QPSK transmission experiment, showing a large Q factor penalty associated with the combination of high forward pumping and high reflectivities.

Optical signal suppression by a cascaded SOA/RSOA for wavelength reusing reflective PON upstream transmission.

PubMed

Jung, Sang Min; Mun, Kyoung Hak; Kang, Soo Min; Han, Sang Kook

2017-09-18

An optical signal suppression technique based on a cascaded SOA and RSOA is proposed for the reflective passive optical networks (PONs) with wavelength division multiplexing (WDM). By suppressing the downstream signal of the optical carrier, the proposed reflective PON effectively reuses the downstream optical carrier for upstream signal transmission. As an experimental demonstration, we show that the proposed optical signal suppression technique is effective in terms of the signal bandwidth and bit-error-rate (BER) performance of the remodulated upstream transmission.

Water Pollution Detection by Reflectance Measurements

NASA Technical Reports Server (NTRS)

Goolsby, A. D.

1971-01-01

Measurement of the intensity of light reflected from various planar liquid surfaces has been performed. The results of this brief study show that the presence of a film of foreign material floating on a reference substrate is easily detected by reflectance measurement if the two liquids possess significantly different refractive indices, for example, oil (n = 1.40) and water (n = 1.33). Additional study of various optical configurations, and the building and testing of a prototype monitoring device revealed that the method is sufficiently practical for application to continuous water quality monitoring.

Study of reflection gratings recorded in polyvinyl alcohol/acrylamide-based photopolymer.

PubMed

Fuentes, Rosa; Fernández, Elena; García, Celia; Beléndez, Augusto; Pascual, Inmaculada

2009-12-01

High-spatial-frequency fringes associated with reflection holographic optical elements are difficult to obtain with currently available recording materials. In this work, holographic reflection gratings were stored in a polyvinyl alcohol/acrylamide photopolymer. This material is formed of acrylamide photopolymer, which is considered interesting material for optical storage applications such as holographic memories. The experimental procedure for examining the high-spatial-frequency response of this material is explained, and the experimental results obtained are presented. With the aim of obtaining the best results, the performance of different material compositions is compared.

Measurement of the properties of lossy materials inside a finite conducting cylinder

NASA Technical Reports Server (NTRS)

Dominek, A.; Park, A.; Caldecott, R.

1988-01-01

Broadband, swept frequency measurement techniques were investigated for the evaluation of the electrical performance of thin, high temperature material coatings. Reflections and transmission measurements using an HP8510B Network Analyzer were developed for an existing high temperature test rig at NASA Lewis Research Center. Reflection measurements will be the initial approach used due to fixture simplicity even though surface wave transmission measurements would be more sensitive. The minimum goal is to monitor the electrical change of the material's performance as a function of temperature. If possible, the materials constitutive parameters, epsilon and muon will be found.

Nonreciprocal reflection-beam isolators for far-infrared use

NASA Technical Reports Server (NTRS)

Kanda, M.; May, W. G.

1973-01-01

Magnetoplasma reflection-beam isolators for submillimeter-wave use are discussed in theory and experiment. The basic device uses the Kerr transverse magnetooptic effect (plane of polarization of the EM wave in the plane of incidence, which is perpendicular to a dc magnetic field) in InSb near room temperature. When the semiconductor slab is covered with a thin dielectric layer acting as a matching transformer, improved performance is predicted and observed at 337 microns, and very efficient isolator performance is predicted for 118 microns. Physical arguments are presented to explain the nonreciprocal phenomenon and lead to better device design.

Computer Program for Calculation of Complex Chemical Equilibrium Compositions, Rocket Performance, Incident and Reflected Shocks, and Chapman-Jouguet Detonations. Interim Revision, March 1976

NASA Technical Reports Server (NTRS)

Gordon, S.; Mcbride, B. J.

1976-01-01

A detailed description of the equations and computer program for computations involving chemical equilibria in complex systems is given. A free-energy minimization technique is used. The program permits calculations such as (1) chemical equilibrium for assigned thermodynamic states (T,P), (H,P), (S,P), (T,V), (U,V), or (S,V), (2) theoretical rocket performance for both equilibrium and frozen compositions during expansion, (3) incident and reflected shock properties, and (4) Chapman-Jouguet detonation properties. The program considers condensed species as well as gaseous species.

Emulation and design of terahertz reflection-mode confocal scanning microscopy based on virtual pinhole

NASA Astrophysics Data System (ADS)

Yang, Yong-fa; Li, Qi

2014-12-01

In the practical application of terahertz reflection-mode confocal scanning microscopy, the size of detector pinhole is an important factor that determines the performance of spatial resolution characteristic of the microscopic system. However, the use of physical pinhole brings some inconvenience to the experiment and the adjustment error has a great influence on the experiment result. Through reasonably selecting the parameter of matrix detector virtual pinhole (VPH), it can efficiently approximate the physical pinhole. By using this approach, the difficulty of experimental calibration is reduced significantly. In this article, an imaging scheme of terahertz reflection-mode confocal scanning microscopy that is based on the matrix detector VPH is put forward. The influence of detector pinhole size on the axial resolution of confocal scanning microscopy is emulated and analyzed. Then, the parameter of VPH is emulated when the best axial imaging performance is reached.

Spatial-Heterodyne Interferometry For Reflection And Transm Ission (Shirt) Measurements

DOEpatents

Hanson, Gregory R [Clinton, TN; Bingham, Philip R [Knoxville, TN; Tobin, Ken W [Harriman, TN

2006-02-14

Systems and methods are described for spatial-heterodyne interferometry for reflection and transmission (SHIRT) measurements. A method includes digitally recording a first spatially-heterodyned hologram using a first reference beam and a first object beam; digitally recording a second spatially-heterodyned hologram using a second reference beam and a second object beam; Fourier analyzing the digitally recorded first spatially-heterodyned hologram to define a first analyzed image; Fourier analyzing the digitally recorded second spatially-heterodyned hologram to define a second analyzed image; digitally filtering the first analyzed image to define a first result; and digitally filtering the second analyzed image to define a second result; performing a first inverse Fourier transform on the first result, and performing a second inverse Fourier transform on the second result. The first object beam is transmitted through an object that is at least partially translucent, and the second object beam is reflected from the object.

IR Imaging Study on Heater Performamnce of Outside Rearview Mirrors for Automobiles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Hsin; England, Todd W

Adhesive bonded electrical heaters have been used in outside rearview mirrors of automobiles in order to act as defrosters. Entrapment of air pockets between the heater and the mirror can affects the performance and structural integrity of the mirror assembly. Since painting over the mirror is not an option in the production environment, the biggest challenge for IR imaging is to minimize surface reflection. Looking through a smooth, highly reflective first-surface mirror and a 2 mm thick glass without picking up other heat sources in the room, such as people, electronics equipment and the camera itself, requires careful planning andmore » effective shielding. In this paper, we present our method of avoiding mirror reflection and IR images of the heated mirror in operation. Production heaters and heaters with artificial defect were studied. The IR imaging method has shown to be an effective tool for heater quality control and performance studies.« less

Broadband high-efficiency half-wave plate: a supercell-based plasmonic metasurface approach.

PubMed

Ding, Fei; Wang, Zhuoxian; He, Sailing; Shalaev, Vladimir M; Kildishev, Alexander V

2015-04-28

We design, fabricate, and experimentally demonstrate an ultrathin, broadband half-wave plate in the near-infrared range using a plasmonic metasurface. The simulated results show that the linear polarization conversion efficiency is over 97% with over 90% reflectance across an 800 nm bandwidth. Moreover, simulated and experimental results indicate that such broadband and high-efficiency performance is also sustained over a wide range of incident angles. To further obtain a background-free half-wave plate, we arrange such a plate as a periodic array of integrated supercells made of several plasmonic antennas with high linear polarization conversion efficiency, consequently achieving a reflection-phase gradient for the cross-polarized beam. In this design, the anomalous (cross-polarized) and the normal (copolarized) reflected beams become spatially separated, hence enabling highly efficient and robust, background-free polarization conversion along with broadband operation. Our results provide strategies for creating compact, integrated, and high-performance plasmonic circuits and devices.

Reframing Photographic Research Methods in Human Geography: A Long-Term Reflection

ERIC Educational Resources Information Center

Hall, Tim

2015-01-01

This paper offers a long-term reflection on the introduction of a photographic research project into a third-year undergraduate Human Geography module. The findings indicate that, whilst the students valued the project, it did impact on their overall performance, their evaluation of the module and the ways in which they spoke about it. The paper…

Reflections on the GUN CONTROL Simulation: Pedagogical Implications for EAP Writing Classes

ERIC Educational Resources Information Center

Salies, Tania Gastao

2007-01-01

This article critically reflects on the GUN CONTROL simulation (Salies, 1994a) by retaking ideas advanced by Salies (2002) and applying them to the context of English for Academic Purposes (EAP) writing classes in Brazil. It examines how controlled practice relates to learners' performance on the first draft in a simulation-based content unit…

What Is Normal, True, and Right: A Critical Discourse Analysis of Students' Written Resistance Strategies on LGBTQ Topics

ERIC Educational Resources Information Center

Jaekel, Kathryn

2016-01-01

This study examines how students perform resistance to lesbian, gay, bisexual, transgender, and queer topics in their written reflections in a higher education diversity course. Using a three-tiered critical discourse analysis , this article maps students' resistant textual devices in their written reflections, analyzes the institutional setting…

Bury My Heart in Doha: Reflections on Performing Western Academia Overseas

ERIC Educational Resources Information Center

Wright, Zachary

2014-01-01

Critical reflection on the course of the Western university system has never been more important than at the juncture of its exportation around the world. The importation of Western academic institutions in the modernizing states of the Muslim world is fraught with contradictions, responding to the desire to craft a citizenship recognizable to the…

Arugula, Pine Nuts, and Hegemony: Seven Women's Choreopoetic Reflection on the Absence of Cultural Relevance in Educational Discourse

ERIC Educational Resources Information Center

William-White, Lisa; Sagir, Aneela; Flores, Nancy; Jung, Gretchen; Ramirez, Angela; Osalbo, Jennifer; Doan, Hong-An

2012-01-01

Choreopoetic narrative storytelling is presented here, where discourse centered on the intersections of race, class, identity, and critical consciousness is performed in a multi-perspectival interpretation of the hegemonic discourses dominating the educational domain as a result of No Child Left Behind. This interpretative and reflective piece…

Scaffolding and Mediating for Creativity: Suggestions from Reflecting on Practice in Order to Develop the Teaching and Learning of Gymnastics

ERIC Educational Resources Information Center

Griggs, Gerald; McGregor, Debra

2012-01-01

This article takes a reflective stance on the development of practice in scaffolding and mediating for creativity and potentially better performance in gymnastics. The pedagogical approach outlined illustrates how an experienced practitioner can adopt mediational (rather than meddling) and scaffolding techniques to focus on supporting the…

A Recommended Engineering Application of the Method for Evaluating the Visual Significance of Reflected Glare.

ERIC Educational Resources Information Center

Blackwell, H. Richard

1963-01-01

An application method for evaluating the visual significance of reflected glare is described, based upon a number of decisions with respect to the relative importance of various aspects of visual performance. A standardized procedure for evaluating the overall effectiveness of lighting from photometric data on materials or installations is needed…

Will algorithms modified with soil and weather information improve in-field reflectance-sensing corn nitrogen applications?

USDA-ARS?s Scientific Manuscript database

Nitrogen (N) needs to support corn (Zea mays L.) production can be highly variable within fields. Canopy reflectance sensing for assessing crop N health has been implemented on many farmers’ fields to side-dress or top-dress variable-rate N application, but at times farmers report the performance of...

Alternative Measurement Paradigms for Measuring Executive Functions: SEM (Formative and Reflective Models) and IRT (Rasch Models)

ERIC Educational Resources Information Center

Engelhard, George, Jr.; Wang, Jue

2014-01-01

The authors of the Focus article pose important questions regarding whether or not performance-based tasks related to executive functioning are best viewed as reflective or formative indicators. Miyake and Friedman (2012) define executive functioning (EF) as "a set of general-purpose control mechanisms, often linked to the prefrontal cortex…

Using Social Media (Blog) in the Classroom: Reflecting Lecturer's Pedagogical Approach and Students (In-Service Teachers) Intrinsic Motivation

ERIC Educational Resources Information Center

Abulibdeh, Enas S.

2013-01-01

The demand of responsibilities among teachers has evolved not only in classroom management but also to the extent of promoting communication and interpersonal skills. Social media is integrated in schools and higher learning institutions for communication and reflection of learning which enhance teachers' performance in leadership quality and…

Individual Differences in Selective Attention among Prereaders: A Key to Mirror-Image Confusions.

ERIC Educational Resources Information Center

Casey, M. Beth

1986-01-01

Experiment 1 examined the position that mirror-image confusions reflect an inability among three- to five-year-olds to determine whether their performance level differences reflect differences among nonreaders already attending and those not yet attending to reading cues. Experiment 2 examined the Experiment 1 four- and five-year-olds, identified…

A Simple Student Laboratory on Osmotic Flow, Osmotic Pressure, and the Reflection Coefficient.

ERIC Educational Resources Information Center

Feher, Joseph J.; Ford, George D.

1995-01-01

Describes a laboratory exercise containing a practical series of experiments that novice students can perform within two hours. The exercise provides a confirmation of van't Hoff's law while placing more emphasis on osmotic flow than pressure. Students can determine parameters such as the reflection coefficient which stress the interaction of both…

Player-Driven Video Analysis to Enhance Reflective Soccer Practice in Talent Development

ERIC Educational Resources Information Center

Hjort, Anders; Henriksen, Kristoffer; Elbæk, Lars

2018-01-01

In the present article, we investigate the introduction of a cloud-based video analysis platform called Player Universe (PU). Video analysis is not a new performance-enhancing element in sports, but PU is innovative in how it facilitates reflective learning. Video analysis is executed in the PU platform by involving the players in the analysis…

Prediction of olive quality using FT-NIR spectroscopy in reflectance and transmittance modes

USDA-ARS?s Scientific Manuscript database

The objective of this research was to use FT-NIR spectroscopy to predict the firmness, oil content and color of two olive (Olea europaea L) varieties (‘Ayvalik’ and ‘Gemlik’). Spectral measurements were performed on the intact olives for the wavelengths of 780-2500 nm in reflectance and for 800-1725...

Optical detection of oil on water

NASA Technical Reports Server (NTRS)

Millard, J. P.; Arvesen, J. C.

1973-01-01

Three radiometric techniques utilizing sunlight reflected and backscattered from water bodies have potential application for remote sensing of oil spills. Oil on water can be detected by viewing perpendicular polarization component of reflected light or difference between polarization components. Best detection is performed in ultraviolet or far-red portions of spectrum and in azimuth directions toward or opposite sun.

Evaluation of Critical Thinking and Reflective Thinking Skills among Science Teacher Candidates

ERIC Educational Resources Information Center

Demir, Sibel

2015-01-01

The aim of this study was to evaluate and determine the critical thinking and reflective thinking skills of science teacher candidates. The study was performed with the participation of 30 teacher candidates enrolled in the science teaching department of a university in Turkey. Scales administered during the study included the California Critical…

Hyperspectral Fluorescence and Reflectance Imaging Instrument

NASA Technical Reports Server (NTRS)

Ryan, Robert E.; O'Neal, S. Duane; Lanoue, Mark; Russell, Jeffrey

2008-01-01

The system is a single hyperspectral imaging instrument that has the unique capability to acquire both fluorescence and reflectance high-spatial-resolution data that is inherently spatially and spectrally registered. Potential uses of this instrument include plant stress monitoring, counterfeit document detection, biomedical imaging, forensic imaging, and general materials identification. Until now, reflectance and fluorescence spectral imaging have been performed by separate instruments. Neither a reflectance spectral image nor a fluorescence spectral image alone yields as much information about a target surface as does a combination of the two modalities. Before this system was developed, to benefit from this combination, analysts needed to perform time-consuming post-processing efforts to co-register the reflective and fluorescence information. With this instrument, the inherent spatial and spectral registration of the reflectance and fluorescence images minimizes the need for this post-processing step. The main challenge for this technology is to detect the fluorescence signal in the presence of a much stronger reflectance signal. To meet this challenge, the instrument modulates artificial light sources from ultraviolet through the visible to the near-infrared part of the spectrum; in this way, both the reflective and fluorescence signals can be measured through differencing processes to optimize fluorescence and reflectance spectra as needed. The main functional components of the instrument are a hyperspectral imager, an illumination system, and an image-plane scanner. The hyperspectral imager is a one-dimensional (line) imaging spectrometer that includes a spectrally dispersive element and a two-dimensional focal plane detector array. The spectral range of the current imaging spectrometer is between 400 to 1,000 nm, and the wavelength resolution is approximately 3 nm. The illumination system consists of narrowband blue, ultraviolet, and other discrete wavelength light-emitting-diode (LED) sources and white-light LED sources designed to produce consistently spatially stable light. White LEDs provide illumination for the measurement of reflectance spectra, while narrowband blue and UV LEDs are used to excite fluorescence. Each spectral type of LED can be turned on or off depending on the specific remote-sensing process being performed. Uniformity of illumination is achieved by using an array of LEDs and/or an integrating sphere or other diffusing surface. The image plane scanner uses a fore optic with a field of view large enough to provide an entire scan line on the image plane. It builds up a two-dimensional image in pushbroom fashion as the target is scanned across the image plane either by moving the object or moving the fore optic. For fluorescence detection, spectral filtering of a narrowband light illumination source is sometimes necessary to minimize the interference of the source spectrum wings with the fluorescence signal. Spectral filtering is achieved with optical interference filters and absorption glasses. This dual spectral imaging capability will enable the optimization of reflective, fluorescence, and fused datasets as well as a cost-effective design for multispectral imaging solutions. This system has been used in plant stress detection studies and in currency analysis.

Performance Constraints in Early Language: The Case of Subjectless Sentences.

ERIC Educational Resources Information Center

Gerken, LouAnn

A discussion of English-speaking children's use of subjectless sentences contrasts the competence and performance explanations for the phenomenon. In particular, it reviews evidence indicating that the phenomenon does not reflect linguistic competence, but rather performance constraints. A tentative model of children's production is presented…

32 CFR 724.109 - Types of administrative discharges.

Code of Federal Regulations, 2010 CFR

2010-07-01

... reflecting a member's military behavior and performance of duty during a specific period of service. The... of an Honorable Discharge is contingent upon proper military behavior and performance of duty. (2... behavior and performance of duty which is not sufficiently meritorious to warrant an Honorable Discharge...

32 CFR 724.109 - Types of administrative discharges.

Code of Federal Regulations, 2011 CFR

2011-07-01

... reflecting a member's military behavior and performance of duty during a specific period of service. The... of an Honorable Discharge is contingent upon proper military behavior and performance of duty. (2... behavior and performance of duty which is not sufficiently meritorious to warrant an Honorable Discharge...

32 CFR 724.109 - Types of administrative discharges.

Code of Federal Regulations, 2013 CFR

2013-07-01

... reflecting a member's military behavior and performance of duty during a specific period of service. The... of an Honorable Discharge is contingent upon proper military behavior and performance of duty. (2... behavior and performance of duty which is not sufficiently meritorious to warrant an Honorable Discharge...

32 CFR 724.109 - Types of administrative discharges.

Code of Federal Regulations, 2012 CFR

2012-07-01

... reflecting a member's military behavior and performance of duty during a specific period of service. The... of an Honorable Discharge is contingent upon proper military behavior and performance of duty. (2... behavior and performance of duty which is not sufficiently meritorious to warrant an Honorable Discharge...

32 CFR 724.109 - Types of administrative discharges.

Code of Federal Regulations, 2014 CFR

2014-07-01

... reflecting a member's military behavior and performance of duty during a specific period of service. The... of an Honorable Discharge is contingent upon proper military behavior and performance of duty. (2... behavior and performance of duty which is not sufficiently meritorious to warrant an Honorable Discharge...

30 CFR 828.2 - Objectives.

Code of Federal Regulations, 2011 CFR

2011-07-01

... PERFORMANCE STANDARDS SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-IN SITU PROCESSING § 828.2 Objectives. This part is intended to ensure that all in situ processing activities are conducted in a manner which... performance, reclamation and design standards to reflect the nature of in situ processing. [44 FR 15455, Mar...

30 CFR 828.2 - Objectives.

Code of Federal Regulations, 2012 CFR

2012-07-01

... PERFORMANCE STANDARDS SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-IN SITU PROCESSING § 828.2 Objectives. This part is intended to ensure that all in situ processing activities are conducted in a manner which... performance, reclamation and design standards to reflect the nature of in situ processing. [44 FR 15455, Mar...

30 CFR 828.2 - Objectives.

Code of Federal Regulations, 2014 CFR

2014-07-01

... PERFORMANCE STANDARDS SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-IN SITU PROCESSING § 828.2 Objectives. This part is intended to ensure that all in situ processing activities are conducted in a manner which... performance, reclamation and design standards to reflect the nature of in situ processing. [44 FR 15455, Mar...

30 CFR 828.2 - Objectives.

Code of Federal Regulations, 2013 CFR

2013-07-01

... PERFORMANCE STANDARDS SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-IN SITU PROCESSING § 828.2 Objectives. This part is intended to ensure that all in situ processing activities are conducted in a manner which... performance, reclamation and design standards to reflect the nature of in situ processing. [44 FR 15455, Mar...

Bioinspired Polymeric Photonic Crystals for High Cycling pH-Sensing Performance.

PubMed

Fei, Xiang; Lu, Tao; Ma, Jun; Wang, Wanlin; Zhu, Shenmin; Zhang, Di

2016-10-12

Artificial photonic crystals (PCs) have been extensively studied to improve the sensing performance of poly(acrylic acid) (PAAc), as it can transform the PAAc volume change into optical signal which is easier to read. Nevertheless, these PCs are limited by the monostructure. We herein developed new photonic crystals (PCs) by coating acrylic acid and acrylamide (AAm) via in situ copolymerization onto Papilio paris wings having hierarchical, lamellar structure. Our PCs exhibited high performance of color tunability to environmental pH, as detected by reflectance spectra and visual observation. The introduction of AAm into the system created covalent bonding which robustly bridged the polymer with the wings, leading to an accurate yet broad variation of reflection wavelength to gauge environmental pH. The reflection wavelength can be tailored by the refractive index of the lamellar interspacing due to the swelling/deswelling of the polymer. The mechanism is not only supported by experimenta but proved by finite-difference time-domain simulation. Moreover, It is worth noting that the covalent bonding has provided the PCs-based pH sensor with high cycling performance, implying great potential in practical applications. The simple fabrication process is applicable to the development of a wide variety of stimuli-responsive PCs taking advantage of other polymers.

Operational and environmental performance in China's thermal power industry: Taking an effectiveness measure as complement to an efficiency measure.

PubMed

Wang, Ke; Zhang, Jieming; Wei, Yi-Ming

2017-05-01

The trend toward a more fiercely competitive and strictly environmentally regulated electricity market in several countries, including China has led to efforts by both industry and government to develop advanced performance evaluation models that adapt to new evaluation requirements. Traditional operational and environmental efficiency measures do not fully consider the influence of market competition and environmental regulations and, thus, are not sufficient for the thermal power industry to evaluate its operational performance with respect to specific marketing goals (operational effectiveness) and its environmental performance with respect to specific emissions reduction targets (environmental effectiveness). As a complement to an operational efficiency measure, an operational effectiveness measure not only reflects the capacity of an electricity production system to increase its electricity generation through the improvement of operational efficiency, but it also reflects the system's capability to adjust its electricity generation activities to match electricity demand. In addition, as a complement to an environmental efficiency measure, an environmental effectiveness measure not only reflects the capacity of an electricity production system to decrease its pollutant emissions through the improvement of environmental efficiency, but it also reflects the system's capability to adjust its emissions abatement activities to fulfill environmental regulations. Furthermore, an environmental effectiveness measure helps the government regulator to verify the rationality of its emissions reduction targets assigned to the thermal power industry. Several newly developed effectiveness measurements based on data envelopment analysis (DEA) were utilized in this study to evaluate the operational and environmental performance of the thermal power industry in China during 2006-2013. Both efficiency and effectiveness were evaluated from the three perspectives of operational, environmental, and joint adjustments to each electricity production system. The operational and environmental performance changes over time were also captured through an effectiveness measure based on the global Malmquist productivity index. Our empirical results indicated that the performance of China's thermal power industry experienced significant progress during the study period and that policies regarding the development and regulation of the thermal power industry yielded the expected effects. However, the emissions reduction targets assigned to China's thermal power industry are loose and conservative. Copyright © 2017 Elsevier Ltd. All rights reserved.

The effect of geometric and electric constraints on the performance of polymer-stabilized cholesteric liquid crystals with a double-handed circularly polarized light reflection band

NASA Astrophysics Data System (ADS)

Relaix, Sabrina; Mitov, Michel

2008-08-01

Polymer-stabilized cholesteric liquid crystals (PSCLCs) with a double-handed circularly polarized reflection band are fabricated. The geometric and electric constraints appear to be relevant parameters in obtaining a single-layer CLC structure with a clear-cut double-handed circularly polarized reflection band since light scattering phenomena can alter the reflection properties when the PSCLC is cooled from the elaboration temperature to the operating one. A compromise needs to be found between the LC molecule populations, which are bound to the polymer network due to strong surface effects or not. Besides, a monodomain texture is preserved if the PSCLC is subjected to an electric field at the same time as the thermal process intrinsic to the elaboration process. As a consequence, the light scattering is reduced and both kinds of circularly polarized reflected light beams are put in evidence. Related potential applications are smart reflective windows for the solar light management or reflective polarizer-free displays with higher brightness.

Reflection and Transmission of P-Waves in an Intermediate Layer Lying Between Two Semi-infinite Media

NASA Astrophysics Data System (ADS)

Singh, Pooja; Chattopadhyay, Amares; Srivastava, Akanksha; Singh, Abhishek Kumar

2018-05-01

With a motivation to gain physical insight of reflection as well as transmission phenomena in frozen (river/ocean) situation for example in Antarctica and other coldest place on Earth, the present article undertakes the analysis of reflection and transmission of a plane wave at the interfaces of layered structured comprised of a water layer of finite thickness sandwiched between an upper half-space constituted of ice and a lower isotropic elastic half-space, which may be useful in geophysical exploration in such conditions. A closed form expression of reflection/transmission coefficients of reflected and transmitted waves has been derived in terms of angles of incidence, propagation vector, displacement vector and elastic constants of the media. Expressions corresponding to the energy partition of various reflected and transmitted waves have also been established analytically. It has been remarkably shown that the law of conservation of energy holds good in the entire reflection and transmission phenomena for different angles of incidence. A numerical examples were performed so to graphically portray the analytical findings. Further the deduced results are validated with the pre-established classical results.

Trust and Reflection in Primary Care Practice Redesign.

PubMed

Lanham, Holly Jordan; Palmer, Raymond F; Leykum, Luci K; McDaniel, Reuben R; Nutting, Paul A; Stange, Kurt C; Crabtree, Benjamin F; Miller, William L; Jaén, Carlos Roberto

2016-08-01

To test a conceptual model of relationships, reflection, sensemaking, and learning in primary care practices transitioning to patient-centered medical homes (PCMH). Primary data were collected as part of the American Academy of Family Physicians' National Demonstration Project of the PCMH. We conducted a cross-sectional survey of clinicians and staff from 36 family medicine practices across the United States. Surveys measured seven characteristics of practice relationships (trust, diversity, mindfulness, heedful interrelation, respectful interaction, social/task relatedness, and rich and lean communication) and three organizational attributes (reflection, sensemaking, and learning) of practices. We surveyed 396 clinicians and practice staff. We performed a multigroup path analysis of the data. Parameter estimates were calculated using a Bayesian estimation method. Trust and reflection were important in explaining the characteristics of practice relationships and their associations with sensemaking and learning. The strongest associations between relationships, sensemaking, and learning were found under conditions of high trust and reflection. The weakest associations were found under conditions of low trust and reflection. Trust and reflection appear to play a key role in moderating relationships, sensemaking, and learning in practices undergoing practice redesign. © Health Research and Educational Trust.

Dark, Infrared Reflective, and Superhydrophobic Coatings by Waterborne Resins.

PubMed

Zhang, Jing; Lin, Weiqiang; Zhu, Chenxi; Lv, Jian; Zhang, Weicheng; Feng, Jie

2018-05-15

Recently, infrared reflective pigments possessing deep colors have attracted much attention. However, in polluted air, the coatings consisting of such pigments are easily contaminated which abates infrared reflectivity. In this work, black and infrared reflective pigments, fluorine silicon sol and a small number of SiO 2 nanoparticles were introduced into waterborne epoxy resin emulsion and then coated on an aluminum plate. After drying, black coatings with infrared reflective and superhydrophobic (SH) properties were obtained. The average near-infrared (NIR) reflectivity of the coating over wavelength range of 780-2600 nm can reach 68%, which is much larger than that of carbon black coatings and even approaches that of white nano SiO 2 coatings. Under the irradiation of a 275-W infrared lamp (with height 40 cm), the surface temperature of the coating is 63 °C, which is much lower than that of the carbon black coating (90 °C) and only 7 °C higher than that of the white nano SiO 2 coating. Furthermore, the NIR reflective coating exhibited a typical SH property due to its low surface energy and high surface roughness, which may allow for self-cleaning performance in a practical environment, maintaining the coating's NIR reflective property.

Reflective-impulsive style and conceptual tempo in a gross motor task.

PubMed

Keller, J; Ripoll, H

2001-06-01

The reflective-impulsive construct refers to responses made slowly or quickly in a situation with high uncertainty. Children who are labeled "reflective" take a longer time to respond and make few errors, whereas "impulsive" children are fast and inaccurate. Although the validity of the test and the definition of reflective-impulsive style are well accepted, whether such respond fast or slow to all tasks is questioned. Some children do not fit the dichotomy. Two other groups arise, the fast-accurate and the slow-inaccurate. The response styles of 86 boys, ages 5, 7, and 9 years performing a gross motor task, i.e., hitting a ball with a racquet, were studied. Analysis indicated that the slowest children on the Matching Familiar Figures Test can be faster than the fastest ones and remain more accurate. As the definition of the reflective-impulsive style is based on time, the reflective ones might better be viewed as children who can adapt the response time to the context and thus be more efficient at problem-solving.

[The effect of self-reflection on depression mediated by hardiness].

PubMed

Nakajima, Miho; Hattori, Yosuke; Tanno, Yoshihiko

2015-10-01

Previous studies have shown that two types of private self-consciousness result in opposing effects on depression; one of which is self-rumination, which leads to maladaptive effect, and the other is self-reflection, which leads to an adaptive effect. Although a number of studies have examined the mechanism of the maladaptive effect of self-rumination, only a few studies have examined the mechanism of the adaptive effect of self-reflection. The present study examined the process of how self-reflection affected depression adaptively, Based on the previous findings, we proposed a hypothetical model assuming that hardiness acts as a mediator of self-reflection. To test the validity of the model, structural equation modeling analysis was performed with the cross-sectional data of 155 undergraduate students. The results. suggest that the hypothetical model is valid. According to the present results and previous findings, it is suggested that self-reflection is associated with low levels of depression and mediated by "rich commitment", one component of hardiness.

Chirality-induced polarization effects in the cuticle of scarab beetles: 100 years after Michelson

NASA Astrophysics Data System (ADS)

Arwin, Hans; Magnusson, Roger; Landin, Jan; Järrendahl, Kenneth

2012-04-01

One hundred years ago Michelson discovered circular polarization in reflection from beetles. Today a novel Mueller-matrix ellipsometry setup allows unprecedented detailed characterization of the beetles' polarization properties. A formalism based on elliptical polarization for description of reflection from scarab beetles is here proposed and examples are given on four beetles of different character: Coptomia laevis - a simple dielectric mirror; Cetonia aurata - a left-hand narrow-band elliptical polarizer; Anoplognathus aureus - a broad-band elliptical polarizer; and Chrysina argenteola - a left-hand polarizer for visible light at small angles, whereas for larger angles, red reflected light is right-handed polarized. We confirm the conclusion of previous studies which showed that a detailed quantification of ellipticity and degree of polarization of cuticle reflection can be performed instead of only determining whether reflections are circularly polarized or not. We additionally investigate reflection as a function of incidence angle. This provides much richer information for understanding the behaviour of beetles and for structural analysis.

Estimating surface reflectance from Himawari-8/AHI reflectance channels Using 6SV

NASA Astrophysics Data System (ADS)

Lee, Kyeong-sang; Choi, Sungwon; Seo, Minji; Seong, Noh-hun; Han, Kyung-soo

2017-04-01

TOA (Top Of Atmospheric) reflectance observed by satellite is modified by the influence of atmosphere such as absorbing and scattering by molecular and gasses. Removing TOA reflectance attenuation which is caused by the atmospheric is essential. surface reflectance with compensated atmospheric effects used as important input data for land product such as Normalized Difference Vegetation Index (NDVI), Land Surface Albedo (LSA) and etc. In this study, we Second Simulation of a Satellite Signal in the Solar Spectrum Vector (6SV) Radiative Transfer Model (RTM) for atmospheric correction and estimating surface reflectance from Himawari-8/Advanced Himawari Imager (AHI) reflectance channels. 6SV has the advantage that it has high accuracy by performing the atmospheric correction by dividing the width of the satellite channel by 2.5 nm, but it is slow to use in the operation. So, we use LUT approach to reduce the computation time and avoid the intensive calculation required for retrieving surface reflectance. Estimated surface reflectance data were compared with PROBA-V S1 data to evaluate the accuracy. As a result Root Mean Square Error (RMSE) and bias were about 0.05 and -0.02. It is considered that this error is due to the difference of angle component and Spectral Response Function (SRF) of each channel.

Laser Pulse Bidirectional Reflectance from CALIPSO Mission

NASA Technical Reports Server (NTRS)

Lu, Xiaomei; Hu, Yongxiang; Yang, Yuekui; Liu, Zhaoyan; Vaughan, Mark; Lucker, Patricia; Trepte, Charles

2017-01-01

In this Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) study, we present a simple way of determining laser pulse bidirectional reflectance over snow/ice surface using the Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP) 532 nanometer polarization channels' measurements. The saturated laser pulse returns from snow and ice surfaces are recovered based on surface tail information. The method overview and initial assessment of the method performance will be presented. The retrieved snow surface bidirectional reflectance is compared with reflectance from both CALIOP cloud cover regions and Moderate Resolution Imaging Spectroradiometer (Earth Observing System (EOS)) (MODIS) Bi-directional Reflectance Distribution Function (BRDF) / Albedo model parameters. The comparisons show that the snow surface bidirectional reflectance over Antarctica for saturation region are generally reliable with a mean value of about 0.90 plus or minus 0.10, while the mean surface reflectance from cloud cover region is about 0.84 plus or minus 0.13 and the calculated MODIS reflectance at 555 nanometers from the BRDF / Albedo model with near nadir illumination and viewing angles is about 0.96 plus or minus 0.04. The comparisons here demonstrate that the snow surface reflectance underneath the cloud with cloud optical depth of about 1 is significantly lower than that for a clear sky condition.

Culturally Relevant Performance Pedagogies: Exploring the Value of AfroLatina/o Music Performance Projects at a Hispanic-Serving Institution

ERIC Educational Resources Information Center

Cervantes, Marco

2015-01-01

Within this essay, I reflect on my students' final performative project in my undergraduate Latino Cultural Expressions class at a Hispanic-Serving Institution. I explore how culturally relevant performative pedagogies offer opportunities to examine culture in the classroom beyond mere celebrations of difference and aesthetics. Throughout the…

Investigation of graphene-on-metal substrates for SPR-based sensor using finite-difference time domain.

PubMed

Said, Fairus Atida; Menon, Pulliyaseri Susthitha; Rajendran, Venkatachalam; Shaari, Sahbudin; Majlis, Burhanuddin Y

2017-12-01

In this study, the authors investigated the effects of a single layer graphene as a coating layer on top of metal thin films such as silver, gold, aluminum and copper using finite-difference time domain method. To enhance the resolution of surface plasmon resonance (SPR) sensor, it is necessary to increase the SPR reflectivity and decrease the full-width-half maximum (FWHM) of the SPR curve so that there is minimum uncertainty in the determination of the resonance dip. Numerical data was verified with analytical and experimental data where all the data were in good agreement with resonance angle differing in <10% due to noise present in components such as humidity and temperature. In further analysis, reflectivity and FWHM were compared among four types of metal with various thin film thicknesses where graphene was applied on top of the metal layers, and data was compared against pure conventional metal thin films. A 60 nm-thick Au thin film results in higher performance with reflectivity of 92.4% and FWHM of 0.88° whereas single layer graphene-on-60 nm-thick Au gave reflectivity of 91.7% and FWHM of 1.32°. However, a graphene-on-40 nm-thick Ag also gave good performance with narrower FWHM of 0.88° and reflection spectra of 89.2%.

Color Constancy of Red-Green Dichromats and Anomalous Trichromats

PubMed Central

Foster, David H.; Amano, Kinjiro; Nascimento, Sérgio M. C.

2010-01-01

Purpose. Color-vision deficiency is associated with abnormalities in color matching and color discrimination, but its impact on the ability of people to judge the constancy of surface colors under different lights (color constancy) is less clear. This work had two aims: first, to quantify the degree of color constancy in subjects with congenital red-green color deficiency; second, to test whether the degree of color constancy in anomalous trichromats can be predicted from their Rayleigh anomaloscope matches. Methods. Color constancy of red-green color-deficient subjects was tested in a task requiring the discrimination of illuminant changes from surface-reflectance changes. Mondrian-like colored patterns, generated on the screen of a computer monitor, were used as stimuli to avoid the spatial cues provided by natural objects and scenes. Spectral reflectances were taken from the Munsell Book of Color and from natural scenes. Illuminants were taken from the daylight locus. Results. Protanopes and deuteranopes performed more poorly than normal trichromats with Munsell spectral reflectances but were less impaired with natural spectral reflectances. Protanomalous and deuteranomalous trichromats performed as well as, or almost as well as, normal trichromats, independent of the type of reflectance. Individual differences were not correlated with Rayleigh anomaloscope matches. Conclusions. Despite the evidence of clinical color-vision tests, red-green color-deficient persons are less disadvantaged than might be expected in their judgments of surface colors under different lights. PMID:19892868

Specular reflectance of soiled glass mirrors - Study on the impact of incidence angles

NASA Astrophysics Data System (ADS)

Heimsath, Anna; Lindner, Philip; Klimm, Elisabeth; Schmid, Tobias; Moreno, Karolina Ordonez; Elon, Yehonatan; Am-Shallem, Morag; Nitz, Peter

2016-05-01

The accumulation of dust and soil on the surface of solar reflectors is an important factor reducing the power output of solar power plants. Therefore the effect of accumulated dust on the specular reflectance of solar mirrors should be understood well in order to improve the site-dependent performance prediction. Furthermore, an optimization of the CSP System maintenance, in particular the cleaning cycles, can be achieved. Our measurements show a noticeable decrease of specular reflectance when the angle of incidence is increased. This effect may be explained by shading and blocking mechanisms caused by dirt particles. The main physical causes of radiation loss being absorption and scattering, the near-angle scattering leads to a further decrease of specular reflectance for smaller angles of acceptance. Within this study mirror samples were both outdoor exposed and indoor artificially soiled. For indoor soiling, the mirror samples were artificially soiled in an in-house developed dusting device using both artificial-standardized dust and real dust collected from an arid outdoor test field at the Negev desert. A model function is proposed that approximates the observed reduction of specular reflectance with the incidence angle with a sufficient accuracy and by simple means for this soil type. Hence a first step towards a new approach to improve site dependent performance prediction of solar power plants is taken.

Deconstructing Global Markets through Critical Performative Experiences in Puerto Rico

ERIC Educational Resources Information Center

Medina, Carmen Liliana; Weltsek, Gustave J.

2013-01-01

Critical Performative Pedagogies, the idea that "The nature of drama as a once removed creative experience turns non-critical implicit classroom identity formation into explicit identity performance as it asks participants to actively reflect upon how identity is created and engaged within fictional social interactions." (Weltsek and…

Bodies in Composition: Teaching Writing through Kinesthetic Performance

ERIC Educational Resources Information Center

Butler, Janine

2017-01-01

This article calls on composition instructors to reflect consciously on how we can use our bodies kinesthetically to perform multimodal writing processes through gestural, visual, and spatial modes. Teaching writing through kinesthetic performance can show students that our bodies are being constructed via interaction with audiences, akin to the…

Lunch Period Drama: An Invisible Theatre Performance with High School Students.

ERIC Educational Resources Information Center

Banaszewski, Charles

2001-01-01

Describes how two high school theatre students and the author negotiated preparation, rehearsal, performance, and reflection as they developed and performed Invisible Theatre scripts addressing their school's lunchroom (mis)behavior of excessive litter. Notes that Invisible Theatre is a public theatre which involves the public as participants in…

Illinois Community College System. Performance Report For Fiscal Year 2004

ERIC Educational Resources Information Center

Illinois Community College Board, 2004

2004-01-01

The Illinois Community College System Performance Report replaces the Results Report and reflects an initial effort to increasingly streamline and integrate state outcomes and progress reporting in Illinois. The fresh approach taken this year further combines qualitative information and quantitative data reporting. The Performance Report is…

Mathematical anxiety is linked to reduced cognitive reflection: a potential road from discomfort in the mathematics classroom to susceptibility to biases

PubMed Central

2014-01-01

Background When asked to solve mathematical problems, some people experience anxiety and threat, which can lead to impaired mathematical performance (Curr Dir Psychol Sci 11:181–185, 2002). The present studies investigated the link between mathematical anxiety and performance on the cognitive reflection test (CRT; J Econ Perspect 19:25–42, 2005). The CRT is a measure of a person’s ability to resist intuitive response tendencies, and it correlates strongly with important real-life outcomes, such as time preferences, risk-taking, and rational thinking. Methods In Experiments 1 and 2 the relationships between maths anxiety, mathematical knowledge/mathematical achievement, test anxiety and cognitive reflection were analysed using mediation analyses. Experiment 3 included a manipulation of working memory load. The effects of anxiety and working memory load were analysed using ANOVAs. Results Our experiments with university students (Experiments 1 and 3) and secondary school students (Experiment 2) demonstrated that mathematical anxiety was a significant predictor of cognitive reflection, even after controlling for the effects of general mathematical knowledge (in Experiment 1), school mathematical achievement (in Experiment 2) and test anxiety (in Experiments 1–3). Furthermore, Experiment 3 showed that mathematical anxiety and burdening working memory resources with a secondary task had similar effects on cognitive reflection. Conclusions Given earlier findings that showed a close link between cognitive reflection, unbiased decisions and rationality, our results suggest that mathematical anxiety might be negatively related to individuals’ ability to make advantageous choices and good decisions. PMID:25179230

Optical performance of W/B4C multilayer mirror in the soft x-ray region

NASA Astrophysics Data System (ADS)

Pradhan, P. C.; Majhi, A.; Nayak, M.

2018-03-01

W/B4C x-ray multilayers (MLs) with 300 layer pairs and a period in the range of d = 2-1.6 nm are fabricated and investigated for the x-ray optical element in the soft x-ray regime. The structural analyses of the MLs are carried out by using hard x-ray reflectivity (HXR) measurements at 8.047 keV. Well-defined successive higher order Bragg peaks (up to 3rd order) in HXR data collected up to glancing incidence angles of ˜9° reveal a good quality of the periodic structure. The ML mirrors have an average interface width of ˜0.35 nm and have a compressive residual stress of ˜0.183 GPa and 0. 827 GPa for d = 1.62 nm and d = 1.98 nm, respectively. MLs maintain structural stability over a long time, with a slight increase in interface widths of the W layers by 0.1 nm due to self-diffusion. Soft x-ray reflectivity (SXR) performances are evaluated in the energy range of 650 to 1500 eV. At energy ˜ 1489 eV, measured reflectivities (energy resolution, ΔE) are ˜ 10% (19 eV) and 4.5% (13 eV) at glancing incident angles of 12.07° and 15° for MLs having periods of 1.98 nm and 1.62 nm, respectively. The optical performance from 1600 eV to 4500 eV is theoretically analysed by considering the measured structural parameters. The structure-stress-optical performance is correlated on the basis of the mechanism of film growth. The implications of W/B4C MLs are discussed, particularly with respect to the development of ML optics with high spectral selectivity and reflectance for soft x-ray instruments.

Military readiness: an exploration of the relationship between marksmanship and visual acuity.

PubMed

Wells, Kenney H; Wagner, Heidi; Reich, Lewis N; Hardigan, Patrick C

2009-04-01

The United States military relies on visual acuity standards to assess enlistment induction and military occupational specialty eligibility, as well as to monitor soldiers' combat vision readiness. However, these vision standards are not evidence based and may not accurately reflect appropriate standards for military readiness or reflect a correlation between visual acuity and occupational performance. The aim of this study was to investigate the relationship between visual acuity and marksmanship performance using a single blind trial with the Engagement Skills Trainer 2000. Marksmanship performance was evaluated in 28 subjects under simulated day and night conditions with habitual spectacle prescription and contact lenses that created visual blur. Panel Poisson regression using an independent correlation structure revealed significant differences (p < 0.001) as visual acuity decreased from 20/25 to 20/50. We conclude that marksmanship performance decreases as visual acuity decreases. We believe that this relationship supports the use of a visual acuity requirement.

Optimization and performance evaluation of a conical mirror based fluorescence molecular tomography imaging system

NASA Astrophysics Data System (ADS)

Zhao, Yue; Zhang, Wei; Zhu, Dianwen; Li, Changqing

2016-03-01

We performed numerical simulations and phantom experiments with a conical mirror based fluorescence molecular tomography (FMT) imaging system to optimize its performance. With phantom experiments, we have compared three measurement modes in FMT: the whole surface measurement mode, the transmission mode, and the reflection mode. Our results indicated that the whole surface measurement mode performed the best. Then, we applied two different neutral density (ND) filters to improve the measurement's dynamic range. The benefits from ND filters are not as much as predicted. Finally, with numerical simulations, we have compared two laser excitation patterns: line and point. With the same excitation position number, we found that the line laser excitation had slightly better FMT reconstruction results than the point laser excitation. In the future, we will implement Monte Carlo ray tracing simulations to calculate multiple reflection photons, and create a look-up table accordingly for calibration.

Sensor modeling and demonstration of a multi-object spectrometer for performance-driven sensing

NASA Astrophysics Data System (ADS)

Kerekes, John P.; Presnar, Michael D.; Fourspring, Kenneth D.; Ninkov, Zoran; Pogorzala, David R.; Raisanen, Alan D.; Rice, Andrew C.; Vasquez, Juan R.; Patel, Jeffrey P.; MacIntyre, Robert T.; Brown, Scott D.

2009-05-01

A novel multi-object spectrometer (MOS) is being explored for use as an adaptive performance-driven sensor that tracks moving targets. Developed originally for astronomical applications, the instrument utilizes an array of micromirrors to reflect light to a panchromatic imaging array. When an object of interest is detected the individual micromirrors imaging the object are tilted to reflect the light to a spectrometer to collect a full spectrum. This paper will present example sensor performance from empirical data collected in laboratory experiments, as well as our approach in designing optical and radiometric models of the MOS channels and the micromirror array. Simulation of moving vehicles in a highfidelity, hyperspectral scene is used to generate a dynamic video input for the adaptive sensor. Performance-driven algorithms for feature-aided target tracking and modality selection exploit multiple electromagnetic observables to track moving vehicle targets.

Reflectivities of uniform and broken marine stratiform clouds

NASA Technical Reports Server (NTRS)

Coakley, James A., Jr.

1990-01-01

Plane-parallel radiative transfer models are often used to estimate the effects of clouds on the earth's energy budget and to retrieve cloud properties from satellite observations. An attempt is made to assess the performance of such models by using AVHRR data collected during the FIRE MARINE Stratus IFO to determine the reflectivities and, in particular, the anisotropy of the reflected radiances for the clouds observed during the field experiment. The intent is to determine the anisotropy for conditions that are overcast and to compare this anisotropy with that produced by the same cloud when broken. The observations are used to quantify aspects of the differences between reflection by plane-parallel clouds and non-planar clouds expected on the basis of theoretical studies.

Adaptive infrared-reflecting systems inspired by cephalopods

NASA Astrophysics Data System (ADS)

Xu, Chengyi; Stiubianu, George T.; Gorodetsky, Alon A.

2018-03-01

Materials and systems that statically reflect radiation in the infrared region of the electromagnetic spectrum underpin the performance of many entrenched technologies, including building insulation, energy-conserving windows, spacecraft components, electronics shielding, container packaging, protective clothing, and camouflage platforms. The development of their adaptive variants, in which the infrared-reflecting properties dynamically change in response to external stimuli, has emerged as an important unmet scientific challenge. By drawing inspiration from cephalopod skin, we developed adaptive infrared-reflecting platforms that feature a simple actuation mechanism, low working temperature, tunable spectral range, weak angular dependence, fast response, stability to repeated cycling, amenability to patterning and multiplexing, autonomous operation, robust mechanical properties, and straightforward manufacturability. Our findings may open opportunities for infrared camouflage and other technologies that regulate infrared radiation.

Aerial photographic water color variations from pollution in the James River

NASA Technical Reports Server (NTRS)

Bressette, W. E.

1978-01-01

A photographic flight was made over the James River on May 17, 1977. The data show that, in general, James River water has very high sunlight reflectance. In the Bailey Bay area this reflectance is drastically reduced. Also shown is a technique for normalizing off-axis variations in radiance film exposure from camera falloff and uneven sunlight conditions to the nadir value. After data normalization, a spectral analysis is performed that identifies Bailey Creek water in James River water. The spectral results when compared with laboratory spectrometer data indicate that reflectance from James River water is dominated by suspended matter, while the substance most likely responsible for reduced reflectance in Bailey Creek water is dissolved organic carbon.

Gradient Structure Design of Flexible Waterborne Polyurethane Conductive Films for Ultraefficient Electromagnetic Shielding with Low Reflection Characteristic.

PubMed

Xu, Yadong; Yang, Yaqi; Yan, Ding-Xiang; Duan, Hongji; Zhao, Guizhe; Liu, Yaqing

2018-06-06

Highly efficient electromagnetic shielding materials entailing strong electromagnetic wave absorption and low reflection have become an increasing requirement for next-generation communication technologies and high-power electronic instruments. In this study, a new strategy is employed to provide flexible waterborne polyurethane composite films with an ultra-efficient electromagnetic shielding effectiveness (EMI SE) and low reflection by constructing gradient shielding layers with a magnetic ferro/ferric oxide deposited on reduced graphene oxide (rGO@Fe 3 O 4 ) and silver-coated tetraneedle-like ZnO whisker (T-ZnO/Ag) functional nanoparticles. Because of the differences in density between rGO@Fe 3 O 4 and T-ZnO/Ag, a gradient structure is automatically formed during the film formation process. The gradient distribution of rGO@Fe 3 O 4 over the whole thickness range forms an efficient electromagnetic wave absorption network that endows the film with a strong absorption ability on the top side, while a thin layer of high-density T-ZnO/Ag at the bottom constructs a highly conductive network that provides an excellent electromagnetic reflection ability for the film. This specific structure results in an "absorb-reflect-reabsorb" process when electromagnetic waves penetrate into the composite film, leading to an excellent EMI shielding performance with an extremely low reflection characteristic at a very low nanofiller content (0.8 vol % Fe 3 O 4 @rGO and 5.7 vol % T-ZnO/Ag): the EMI SE reaches 87.2 dB against the X band with a thickness of only 0.5 mm, while the shielding effectiveness of reflection (SE R ) is only 2.4 dB and the power coefficient of reflectivity ( R) is as low as 0.39. This result means that only 39% of the microwaves are reflected in the propagation process when 99.9999998% are attenuated, which is the lowest value among the reported references. This composite film with remarkable performance is suitable for application in portable and wearable smart electronics, and this method offers an effective strategy for absorption-dominated EMI shielding.

Functional Performance and Associations between Performance Tests and Neurological Assessment Differ in Men and Women with Parkinson's Disease.

PubMed

Medijainen, Kadri; Pääsuke, Mati; Lukmann, Aet; Taba, Pille

2015-01-01

Neurological assessment of a patient with Parkinson's disease (PD) is expected to reflect upon functional performance. As women are known to report more limitations even for same observed functional performance level, present study was designed to examine whether associations between neurological assessments and functional performance differ across genders. 14 men and 14 women with PD participated. Functional performance was assessed by measuring walking speeds on 10-meter walk test (10MWT) and by performing timed-up-and-go-test (TUG). Neurological assessment included Hoehn and Yahr Scale (HY), Movement Disorders Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS), Schwab and England Activities of Daily Living Scale (S-E), and Mini Mental State Examination (MMSE). In women with PD, Kendall's tau-b correlation analyses revealed significant correlations between functional performance tests and neurological assessment measures, with the exception in MMSE. No corresponding associations were found for men, although they demonstrated better functional performance, as expected. Men in similar clinical stage of the PD perform better on functional tests than women. Disease severity reflects upon functional performance differently in men and women with PD. Results indicate that when interpreting the assessment results of both functional performance and neurological assessment tests, the gender of the patient should be taken into consideration.

Managing the Action/Reflection Polarity Through Dialogue: A Path to Transformative Learning. NALL Working Paper.

ERIC Educational Resources Information Center

Laiken, Marilyn E.

At the Ontario Institute for Studies in Education of the University of Ontario, a course entitled Developing and Leading High Performing Teams: Theory and Practice is experimenting with a design that surfaces the action/reflection paradox for the purpose of learning how to manage this polarity. Whether the product is defined as services or goods,…

"Knowing Is Not Enough; We Must Apply": Reflections on a Failed Action Learning Application

ERIC Educational Resources Information Center

Reese, Simon

2015-01-01

This paper reflects upon a sub-optimal action learning application with a strategic business re-design project. The objective of the project was to improve the long-term business performance of a subsidiary business and build the strategic plan. Action learning was introduced to aid the group in expanding their view of the real problems…

An Examination of Reflective Thinking, Learning Approaches, and Self-Efficacy Beliefs at the University of the South Pacific: A Path Analysis Approach

ERIC Educational Resources Information Center

Phan, Huy P.

2007-01-01

This study examined the causal and mediating relations between students' learning approaches, self-efficacy beliefs, stages of reflective thinking, and academic performance. Second-year undergraduate students (n = 241; 118 females, 123 males) in the South Pacific were administered the revised version of Biggs' Study Process Questionnaire, the…

A Reflection on Aging: A Portfolio of Change in Attitudes toward Geriatric Patients during a Clerkship Rotation

ERIC Educational Resources Information Center

Del Duca, Danny; Duque, Gustavo

2006-01-01

The process of students' evaluation in medical schools has changed from a tutor-led evaluation system based on students' performance to a student-based evaluation that involves self-reflection and their level of change in skills and attitudes. At the McGill University Division of Geriatric Medicine, we developed an innovative system of evaluation…

The effect of skin reflectance on thermal traits in a small heliothermic ectotherm.

PubMed

Matthews, Genevieve; Goulet, Celine T; Delhey, Kaspar; Chapple, David G

2016-08-01

Variation in colour patterning is prevalent among and within species. A number of theories have been proposed in explaining its evolution. Because solar radiation interacts with the pigmentation of the integument causing light to either be reflected or absorbed into the body, thermoregulation has been considered to be a primary selective agent, particularly among ectotherms. Accordingly, the colour-mediated thermoregulatory hypothesis states that darker individuals will heat faster and reach higher thermal equilibria while paler individuals will have the opposite traits. It was further predicted that dark colouration would promote slower cooling rates and higher thermal performance temperatures. To test these hypotheses we quantified the reflectance, selected body temperatures, performance optima, as well as heating and cooling rates of an ectothermic vertebrate, Lampropholis delicata. Our results indicated that colour had no influence on thermal physiology, as all thermal traits were uncorrelated with reflectance. We suggest that crypsis may instead be the stronger selective agent as it may have a more direct impact on fitness. Our study has improved our knowledge of the functional differences among individuals with different colour patterns, and the evolutionary significance of morphological variation within species. Copyright © 2016 Elsevier Ltd. All rights reserved.

Weather radar performance monitoring using a metallic-grid ground-scatterer

NASA Astrophysics Data System (ADS)

Falconi, Marta Tecla; Montopoli, Mario; Marzano, Frank Silvio; Baldini, Luca

2017-10-01

The use of ground return signals is investigated for checks on the calibration of power measurements of a polarimetric C-band radar. To this aim, a peculiar permanent single scatterer (PSS) consisting of a big metallic roof with a periodic mesh grid structure and having a hemisphere-like shape is considered. The latter is positioned in the near-field region of the weather radar and its use, as a reference calibrator, shows fairly good results in terms of reflectivity and differential reflectivity monitoring. In addition, the use of PSS indirectly allows to check for the radar antenna de-pointing which is another issue usually underestimated when dealing with weather radars. Because of the periodic structure of the considered PSS, simulations of its electromagnetic behavior were relatively easy to perform. To this goal, we used an electromagnetic Computer-Aided-Design (CAD) with an ad-hoc numerical implementation of a full-wave solution to model our PSS in terms of reflectivity and differential reflectivity factor. Comparison of model results and experimental measurements are then shown in this work. Our preliminary investigation can pave the way for future studies aiming at characterizing ground-clutter returns in a more accurate way for radar calibration purposes.

Shaping electromagnetic waves using software-automatically-designed metasurfaces.

PubMed

Zhang, Qian; Wan, Xiang; Liu, Shuo; Yuan Yin, Jia; Zhang, Lei; Jun Cui, Tie

2017-06-15

We present a fully digital procedure of designing reflective coding metasurfaces to shape reflected electromagnetic waves. The design procedure is completely automatic, controlled by a personal computer. In details, the macro coding units of metasurface are automatically divided into several types (e.g. two types for 1-bit coding, four types for 2-bit coding, etc.), and each type of the macro coding units is formed by discretely random arrangement of micro coding units. By combining an optimization algorithm and commercial electromagnetic software, the digital patterns of the macro coding units are optimized to possess constant phase difference for the reflected waves. The apertures of the designed reflective metasurfaces are formed by arranging the macro coding units with certain coding sequence. To experimentally verify the performance, a coding metasurface is fabricated by automatically designing two digital 1-bit unit cells, which are arranged in array to constitute a periodic coding metasurface to generate the required four-beam radiations with specific directions. Two complicated functional metasurfaces with circularly- and elliptically-shaped radiation beams are realized by automatically designing 4-bit macro coding units, showing excellent performance of the automatic designs by software. The proposed method provides a smart tool to realize various functional devices and systems automatically.

Propellantless Attitude Control of Solar Sail Technology Utilizing Reflective Control Devices

NASA Technical Reports Server (NTRS)

Munday, Jeremy

2016-01-01

Solar sails offer an opportunity for a CubeSatscale, propellant-free spacecraft technology that enables long-term and long-distance missions not possible with traditional methods. Solar sails operate using the transfer of linear momentum from photons of sunlight reflected from the surface of the sail. To propel the spacecraft, no mechanically moving parts, thrusters, or propellant are needed. However, attitude control, or orientation, is still performed using traditional methods involving reaction wheels and propellant ejection, which severely limit mission lifetime. For example, the current state of the art solutions employed by upcoming missions couple solar sails with a state of the art propellant ejection gas system. Here, the use of the gas thruster has limited the lifetime of the mission. To solve the limited mission lifetime problem, the Propellantless Attitude Control of Solar Sail Technology Utilizing Reflective Control Devices project team is working on propellantless attitude control using thin layers of material, an optical film, electrically switchable from transparent to reflective. The technology is based on a polymer-dispersed liquid crystal (PDLC), which allows this switch upon application of a voltage. This technology removes the need for propellant, which reduces weight and cost while improving performance and lifetime.

Polarization properties and microfacet-based modelling of white, grey and coloured matte diffuse reflection standards

NASA Astrophysics Data System (ADS)

Quast, T.; Schirmacher, A.; Hauer, K.-O.; Koo, A.

2018-02-01

To elucidate the influence of polarization in diffuse reflectometry, we performed a series of measurements in several bidirectional geometries and determined the Stokes parameters of the diffusely reflected radiation. Different types of matte reflection standards were used, including several common white standards and ceramic colour standards. The dependence of the polarization on the sample type, wavelength and geometry have been studied systematically, the main influence factors have been identified: The effect is largest at large angles of incidence or detection and at wavelengths where the magnitude of the reflectance is small. The results for the colour standards have been modelled using a microfacet-based reflection theory which is derived from the well-known model of Torrance and Sparrow. Although the theory is very simple and only has three free parameters, the agreement with the measured data is very good, all essential features of the data can be reproduced by the model.

Reversible unidirectional reflection and absorption of PT-symmetry structure under electro-optical modulation

NASA Astrophysics Data System (ADS)

Fang, Yun-tuan; Zhang, Yi-chi; Xia, Jing

2018-06-01

In order to obtain tunable unidirectional device, we assumed an ideal periodic layered Parity-Time (PT) symmetry structure inserted by doped LiNbO3 (LN) interlayers. LN is a typical electro-optical material of which the refractive index depends on the external electric field. In our work, we theoretically investigate the modulation effect of the external electric field on the transmittance and reflectance of the structure through numerical method. Through selected structural parameters, the one-way enhanced reflection and high absorption (above 0.9) behaviors are found. Within a special frequency band (not a single frequency), our theoretical model performs enhanced reflection in one incidence direction and high absorption in the other direction. Furthermore, the directions of enhanced reflection and absorption can be reversed through reversing the direction of applied electric field. Such structure with reversible properties has the potential in designing new optical devices.

Independent Controls of Differently-Polarized Reflected Waves by Anisotropic Metasurfaces

PubMed Central

Ma, Hui Feng; Wang, Gui Zhen; Kong, Gu Sheng; Cui, Tie Jun

2015-01-01

We propose a kind of anisotropic planar metasurface, which has capacity to manipulate the orthogonally-polarized electromagnetic waves independently in the reflection mode. The metasurface is composed of orthogonally I-shaped structures and a metal-grounded plane spaced by a dielectric isolator, with the thickness of about 1/15 wavelength. The normally incident linear-polarized waves will be totally reflected by the metal plane, but the reflected phases of x- and y-polarized waves can be controlled independently by the orthogonally I-shaped structures. Based on this principle, we design four functional devices using the anisotropic metasurfaces to realize polarization beam splitting, beam deflection, and linear-to-circular polarization conversion with a deflection angle, respectively. Good performances have been observed from both simulation and measurement results, which show good capacity of the anisotropic metasurfaces to manipulate the x- and y-polarized reflected waves independently. PMID:25873323

Harnessing Multiple Internal Reflections to Design Highly Absorptive Acoustic Metasurfaces

NASA Astrophysics Data System (ADS)

Shen, Chen; Cummer, Steven A.

2018-05-01

The rapid development of metasurfaces has enabled numerous intriguing applications with acoustically thin sheets. Here we report the theory and experimental realization of a nonresonant sound-absorbing strategy using metasurfaces by harnessing multiple internal reflections. We theoretically and numerically show that the higher-order diffraction of thin gradient-index metasurfaces is tied to multiple internal reflections inside the unit cells. Highly absorbing acoustic metasurfaces can be realized by enforcing multiple internal reflections together with a small amount of loss. A reflective gradient-index acoustic metasurface is designed based on the theory, and we further experimentally verify the performance using a three-dimensional printed prototype. Measurements show over 99% energy absorption at the peak frequency and a 95% energy absorption bandwidth of around 600 Hz. The proposed mechanism provides an alternative route for sound absorption without the necessity of high absorption of the individual unit cells.

Model for the ultrasound reflection from micro-beads and cells distributed in layers on a uniform surface

NASA Astrophysics Data System (ADS)

Couture, O.; Cherin, E.; Foster, F. S.

2007-07-01

A model predicting the reflection of ultrasound from multiple layers of small scattering spheres is developed. Predictions of the reflection coefficient, which takes into account the interferences between the different sphere layers, are compared to measurements performed in the 10-80 MHz and 15-35 MHz frequency range with layers of glass beads and spherical acute myeloid leukemia (AML) cells, respectively. For both types of scatterers, the reflection coefficient increases as a function of their density on the surface for less than three superimposed layers, at which point it saturates at 0.38 for glass beads and 0.02 for AML cells. Above three layers, oscillations of the reflection coefficient due to constructive or destructive interference between layers are observed experimentally and are accurately predicted by the model. The use of such a model could lead to a better understanding of the structures observed in layered tissue images.

Hybrid metasurfaces for microwave reflection and infrared emission reduction.

PubMed

Pang, Yongqiang; Li, Yongfeng; Yan, Mingbao; Liu, Dongqing; Wang, Jiafu; Xu, Zhuo; Qu, Shaobo

2018-04-30

Controlling of electromagnetic wave radiation is of great importance in many fields. In this work, a hybrid metasurface (HMS) is designed to simultaneously reduce the microwave reflection and the infrared emission. The HMS is composed of the metal/dielectric/metal/dielectric/metal configuration. The reflection reduction at microwave frequencies mainly results from the phase cancellation technique, while the infrared emission reduction is due to the reflection of the metal with a high filling ration in the top layer. It has been analytically indicated that reflection reduction with an efficiency larger than 10 dB can be achieved in the frequency band of 8.2-18 GHz, and this has been well verified by the simulated and experimental results. Meanwhile, the designed HMS displays a low emission performance in the infrared band, with the emissivity less than 0.27 from 3 to 14 μm. It is believed that our proposal may find the application of multispectral stealth technology.

Preliminary Analysis of the Performance of the Landsat 8/OLI Land Surface Reflectance Product

NASA Technical Reports Server (NTRS)

Vermote, Eric; Justice, Chris; Claverie, Martin; Franch, Belen

2016-01-01

The surface reflectance, i.e., satellite derived top of atmosphere (TOA) reflectance corrected for the temporally, spatially and spectrally varying scattering and absorbing effects of atmospheric gases and aerosols, is needed to monitor the land surface reliably. For this reason, the surface reflectance, and not TOA reflectance, is used to generate the greater majority of global land products, for example, from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Visible Infrared Imaging Radiometer Suite (VIIRS) sensors. Even if atmospheric effects are minimized by sensor design, atmospheric effects are still challenging to correct. In particular, the strong impact of aerosols in the visible and near infrared spectral range can be difficult to correct, because they can be highly discrete in space and time (e.g., smoke plumes) and because of the complex scattering and absorbing properties of aerosols that vary spectrally and with aerosol size, shape, chemistry and density.

From the generalized reflection law to the realization of perfect anomalous reflectors

PubMed Central

Díaz-Rubio, Ana; Asadchy, Viktar S.; Elsakka, Amr; Tretyakov, Sergei A.

2017-01-01

The use of the generalized Snell’s law opens wide possibilities for the manipulation of transmitted and reflected wavefronts. However, known structures designed to shape reflection wavefronts suffer from significant parasitic reflections in undesired directions. We explore the limitations of the existing solutions for the design of passive planar reflectors and demonstrate that strongly nonlocal response is required for perfect performance. A new paradigm for the design of perfect reflectors based on energy surface channeling is introduced. We realize and experimentally verify a perfect design of an anomalously reflective surface using an array of rectangular metal patches backed by a metallic plate. This conceptually new mechanism for wavefront manipulation allows the design of thin perfect reflectors, offering a versatile design method applicable to other scenarios, such as focusing reflectors, surface wave manipulations, or metasurface holograms, extendable to other frequencies. PMID:28819642

Design of teleoperation system with a force-reflecting real-time simulator

NASA Technical Reports Server (NTRS)

Hirata, Mitsunori; Sato, Yuichi; Nagashima, Fumio; Maruyama, Tsugito

1994-01-01

We developed a force-reflecting teleoperation system that uses a real-time graphic simulator. This system eliminates the effects of communication time delays in remote robot manipulation. The simulator provides the operator with predictive display and feedback of computed contact forces through a six-degree of freedom (6-DOF) master arm on a real-time basis. With this system, peg-in-hole tasks involving round-trip communication time delays of up to a few seconds were performed at three support levels: a real image alone, a predictive display with a real image, and a real-time graphic simulator with computed-contact-force reflection and a predictive display. The experimental results indicate the best teleoperation efficiency was achieved by using the force-reflecting simulator with two images. The shortest work time, lowest sensor maximum, and a 100 percent success rate were obtained. These results demonstrate the effectiveness of simulated-force-reflecting teleoperation efficiency.

Dimensions of the epilepsy foundation concerns index.

PubMed

Loring, David W; Larrabee, Glenn J; Meador, Kimford J; Lee, Gregory P

2005-05-01

We performed principal component analysis (PCA) of the Epilepsy Foundation Concerns Index scale in 189 patients undergoing evaluation for epilepsy surgery. We identified a five-factor solution in which there were no varimax-rotated factors consisting of fewer than two questions. Factor 1 reflects affective impact on enjoyment of life, Factor 2 reflects general autonomy concerns, Factor 3 reflects fear of seizure recurrence, Factor 4 reflects concern of being a burden to one's family, and Factor 5 reflects a perceived lack of understanding by others. Multiple regression using the Quality of Life in Epilepsy--89 question version; Minnesota Multiphasic Personality Inventory--2; Wechsler Adult Intelligence Scale--third edition; and verbal and visual memory tests as predictors demonstrated a different pattern of association with the factor and summary scores. We conclude that the Epilepsy Foundation Concerns Index is multidimensional, and using a global score based on all items may mask specific concerns that may be relevant when applied to individual patients.

Cultural differences in emotion regulation during self-reflection on negative personal experiences.

PubMed

Tsai, William; Lau, Anna S

2013-01-01

Reflecting on negative personal experiences has implications for mood that may vary as a function of specific domains (e.g., achievement vs. interpersonal) and cultural orientation (e.g., interdependence vs. independence). This study investigated cultural differences in the social-cognitive and affective processes undertaken as Easterners and Westerners reflected on negative interpersonal and performance experiences. One hundred Asian Americans and 92 European-American college students were randomly assigned to one of three conditions: interpersonal rejection, achievement failure, or a control condition. Results revealed that Asian Americans experienced greater distress than European Americans after self-reflecting over a failed interpersonal experience, suggesting cultural sensitivity in the relational domain. Consistent with theoretical predictions, analysis of the social cognitive and affective processes that participants engaged in during self-reflection provided some evidence that self-enhancement may buffer distress for European Americans, while emotion suppression may be adaptive for Asian Americans.

Use of Reflection-in-Action and Self-Assessment to Promote Critical Thinking Among Pharmacy Students

PubMed Central

Gregory, Paul AM; Chiu, Stephanie

2008-01-01

Objective To examine whether self-assessment and reflection-in-action improves critical thinking among pharmacy students. Methods A 24-item standardized test of critical thinking was developed utilizing previously-validated questions. Participants were divided into 2 groups (conditions). Those in condition 1 completed the test with no interference; those in condition 2 completed the test but were prompted at specific points during the test to reflect and self-assess. Results A total of 94 undergraduate (BScPhm) pharmacy students participated in this study. Significant differences (p < 0.05) were observed between those who completed the test under condition 1 and condition 2, suggesting reflection and self-assessment may contribute positively to improvement in critical thinking. Conclusions Structured opportunities to reflect-in-action and self-assess may be associated with improvements among pharmacy students in performance of tasks related to critical thinking. PMID:18698383

Oxidation-resistant reflective surfaces for solar dynamic power generation in near Earth orbit

NASA Technical Reports Server (NTRS)

Gulino, D. A.; Mgf2, Sio2, Al2o3, and si3n4, we

1986-01-01

Reflective surfaces for space station power generation systems are required to withstand the atomic oxygen-dominated environment of near Earth orbit. Thin films of platinum and rhodium, which are corrosion resistant reflective metals, have been deposited by ion beam sputter deposition onto various substrate materials. Solar reflectances were then measured as a function of time of exposure to a RF-generated air plasma. Similarly, various protective coating materials, including MgF2, SiO2, Al2O3, and Si3N4, were deposited onto silver-coated substrates and then exposed to the plasma. Analysis of the films both before and after exposure by both ESCA and Auger spectroscopy was also performed. The results indicate that Pt and Rh do not suffer any loss in reflectance over the duration of the tests. Also, each of the coating materials survived the plasma environment. The ESCA and Auger analyses are discussed as well.

Biological versus electronic adaptive coloration: how can one inform the other?

PubMed Central

Kreit, Eric; Mäthger, Lydia M.; Hanlon, Roger T.; Dennis, Patrick B.; Naik, Rajesh R.; Forsythe, Eric; Heikenfeld, Jason

2013-01-01

Adaptive reflective surfaces have been a challenge for both electronic paper (e-paper) and biological organisms. Multiple colours, contrast, polarization, reflectance, diffusivity and texture must all be controlled simultaneously without optical losses in order to fully replicate the appearance of natural surfaces and vividly communicate information. This review merges the frontiers of knowledge for both biological adaptive coloration, with a focus on cephalopods, and synthetic reflective e-paper within a consistent framework of scientific metrics. Currently, the highest performance approach for both nature and technology uses colourant transposition. Three outcomes are envisioned from this review: reflective display engineers may gain new insights from millions of years of natural selection and evolution; biologists will benefit from understanding the types of mechanisms, characterization and metrics used in synthetic reflective e-paper; all scientists will gain a clearer picture of the long-term prospects for capabilities such as adaptive concealment and signalling. PMID:23015522

A mechanism study of sound wave-trapping barriers.

PubMed

Yang, Cheng; Pan, Jie; Cheng, Li

2013-09-01

The performance of a sound barrier is usually degraded if a large reflecting surface is placed on the source side. A wave-trapping barrier (WTB), with its inner surface covered by wedge-shaped structures, has been proposed to confine waves within the area between the barrier and the reflecting surface, and thus improve the performance. In this paper, the deterioration in performance of a conventional sound barrier due to the reflecting surface is first explained in terms of the resonance effect of the trapped modes. At each resonance frequency, a strong and mode-controlled sound field is generated by the noise source both within and in the vicinity outside the region bounded by the sound barrier and the reflecting surface. It is found that the peak sound pressures in the barrier's shadow zone, which correspond to the minimum values in the barrier's insertion loss, are largely determined by the resonance frequencies and by the shapes and losses of the trapped modes. These peak pressures usually result in high sound intensity component impinging normal to the barrier surface near the top. The WTB can alter the sound wave diffraction at the top of the barrier if the wavelengths of the sound wave are comparable or smaller than the dimensions of the wedge. In this case, the modified barrier profile is capable of re-organizing the pressure distribution within the bounded domain and altering the acoustic properties near the top of the sound barrier.

Performance Evaluation of Fiber Bragg Gratings at Elevated Temperatures

NASA Technical Reports Server (NTRS)

Juergens, Jeffrey; Adamovsky, Grigory; Floyd, Bertram

2004-01-01

The development of integrated fiber optic sensors for smart propulsion systems demands that the sensors be able to perform in extreme environments. In order to use fiber optic sensors effectively in an extreme environment one must have a thorough understanding of the sensor s limits and how it responds under various environmental conditions. The sensor evaluation currently involves examining the performance of fiber Bragg gratings at elevated temperatures. Fiber Bragg gratings (FBG) are periodic variations of the refractive index of an optical fiber. These periodic variations allow the FBG to act as an embedded optical filter passing the majority of light propagating through a fiber while reflecting back a narrow band of the incident light. The peak reflected wavelength of the FBG is known as the Bragg wavelength. Since the period and width of the refractive index variation in the fiber determines the wavelengths that are transmitted and reflected by the grating, any force acting on the fiber that alters the physical structure of the grating will change what wavelengths are transmitted and what wavelengths are reflected by the grating. Both thermal and mechanical forces acting on the grating will alter its physical characteristics allowing the FBG sensor to detect both temperature variations and physical stresses, strain, placed upon it. This ability to sense multiple physical forces makes the FBG a versatile sensor. This paper reports on test results of the performance of FBGs at elevated temperatures. The gratings looked at thus far have been either embedded in polymer matrix materials or freestanding with the primary focus of this paper being on the freestanding FBGs. Throughout the evaluation process, various parameters of the FBGs performance were monitored and recorded. These parameters include the peak Bragg wavelength, the power of the Bragg wavelength, and total power returned by the FBG. Several test samples were subjected to identical test conditions to allow for statistical analysis of the data. Test procedures, calibrations, and referencing techniques are presented in the paper along with directions for future research.

Design and Performance of the Vegetation Canopy Lidar (VCL) Laser Transmitter

NASA Technical Reports Server (NTRS)

Coyle, D. Barry; Kay, Richard B.; Lindauer, Steven J., II

2002-01-01

The Vegetation Canopy Lidar (VCL) laser is a Nd:YAG Q-switched, diode side-pumped, zig-zag slab design producing 10 ns, 15 mJ pulses at 1064 nm. It employs an unstable resonator as well as a graded reflectivity output coupler with a Gaussian reflectivity profile. In order to conserve power, a conductively cooled design is employed and is designed to operate over a range of 25 C without active thermal control. The laser is an oscillator-only design and equipped with an 15X beam expander to limit the output divergence to less than 60 microrad. Thermal lensing compensation in the side-pumped slab was performed with different treatments of the x and y portions of the z-directed beam. Performance data as a function of temperature are given.

Atomic force microscopy characterization of Zerodur mirror substrates for the extreme ultraviolet telescopes aboard NASA's Solar Dynamics Observatory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soufli, Regina; Baker, Sherry L.; Windt, David L.

2007-06-01

The high-spatial frequency roughness of a mirror operating at extreme ultraviolet (EUV)wavelengths is crucial for the reflective performance and is subject to very stringent specifications. To understand and predict mirror performance, precision metrology is required for measuring the surface roughness. Zerodur mirror substrates made by two different polishing vendors for a suite of EUV telescopes for solar physics were characterized by atomic force microscopy (AFM). The AFM measurements revealed features in the topography of each substrate that are associated with specific polishing techniques. Theoretical predictions of the mirror performance based on the AFM-measured high-spatial-frequency roughness are in good agreement withmore » EUV reflectance measurements of the mirrors after multilayer coating.« less

Wave reflection effects in the central circulation of American alligators (Alligator mississippiensis): what the heart sees.

PubMed

Syme, Douglas A; Gamperl, A Kurt; Braun, Marvin H; Jones, David R

2006-10-01

A large central compliance is thought to dominate the hemodynamics of all vertebrates except birds and mammals. Yet large crocodilians may adumbrate the avian and mammalian condition and set the stage for significant wave transmission (reflection) effects, with potentially detrimental impacts on cardiac performance. To investigate whether crocodilians exhibit wave reflection effects, pressures and flows were recorded from the right aorta, carotid artery, and femoral artery of six adult, anesthetized American alligators (Alligator mississippiensis) during control conditions and after experimentally induced vasodilation and constriction. Hallmarks of wave reflection phenomena were observed, including marked differences between the measured profiles for flow and pressure, peaking of the femoral pressure pulse, and a diastolic wave in the right aortic pressure profile. Pulse wave velocity and peripheral input impedance increased with progressive constriction, and thus changes in both the timing and magnitude of reflections accounted for the altered reflection effects. Resolution of pressure and flow waves into incident and reflected components showed substantial reflection effects within the right aorta, with reflection coefficients at the first harmonic approaching 0.3 when constricted. Material properties measured from isolated segments of blood vessels revealed a major reflection site at the periphery and, surprisingly, at the junction of the truncus and right aorta. Thus, while our results clearly show that significant wave reflection phenomena are not restricted to birds and mammals, they also suggest that rather than cope with potential negative impacts of reflections, the crocodilian heart simply avoids them because of a large impedance mismatch at the truncus.

Acceleration of domain wall movement by photoirradiation in perovskite-type cobaltite

NASA Astrophysics Data System (ADS)

Okimoto, Y.; Kurashima, M.; Seko, K.; Ishikawa, T.; Onda, K.; Koshihara, S.; Kyomen, T.; Itoh, M.

2011-04-01

Femtosecond reflection spectroscopy was performed on a perovskite-type cobalt oxide, namely, Pr0.5Ca0.5CoO3, that undergoes a photoinduced spin-state transition. After photoirradiation at 30 K, the time profile of the reflectance change shows a broad peak reflecting the propagation of the photodomain (about 60 Co sites per one photon). Analysis of the peak position indicates the sudden increase of the velocity of the propagation with increasing the excitation intensity. Such acceleration with increase in fluence originates from an abrupt sound velocity change driven by a cooperative photoinduced structural transition.

A study of muscular tissue of animal origin by reflection-spectroscopy methods

NASA Astrophysics Data System (ADS)

Plotnikova, L. V.; Nechiporenko, A. P.; Orekhova, S. M.; Plotnikov, P. P.; Ishevskii, A. L.

2017-06-01

A comparative analysis of the spectral characteristics of the surface of muscular tissue of animal origin (pork) and its main components has been performed by the methods of diffuse reflection electronic spectroscopy (DRES) and frustrated total internal reflection IR spectroscopy. The experiments have shown that the application of the DRES method makes it possible to detect more pronounced changes in the surface optical characteristics of muscular tissue and obtain electronic spectra containing information about the component composition of its main parts under successive extraction of sarcoplasmic materials, myofibrillar proteins of the actomyosin complex, and stroma mucopolysaccharides.

High reflectivity mirrors and method for making same

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heikman, Sten; Jacob-Mitos, Matthew; Li, Ting

2016-06-07

A composite high reflectivity mirror (CHRM) with at least one relatively smooth interior surface interface. The CHRM includes a composite portion, for example dielectric and metal layers, on a base element. At least one of the internal surfaces is polished to achieve a smooth interface. The polish can be performed on the surface of the base element, on various layers of the composite portion, or both. The resulting smooth interface(s) reflect more of the incident light in an intended direction. The CHRMs may be integrated into light emitting diode (LED) devices to increase optical output efficiency

Spectral reflectance data of a high temperature stable solar selective coating based on MoSi2 -Si3N4.

PubMed

Hernández-Pinilla, D; Rodríguez-Palomo, A; Álvarez-Fraga, L; Céspedes, E; Prieto, J E; Muñoz-Martín, A; Prieto, C

2016-06-01

Data of optical performance, thermal stability and ageing are given for solar selective coatings (SSC) based on a novel MoSi2-Si3N4 absorbing composite. SSC have been prepared as multilayer stacks formed by silver as metallic infrared reflector, a double layer composite and an antireflective layer (doi: 10.1016/j.solmat.2016.04.001 [1]). Spectroscopic reflectance data corresponding to the optical performance of samples after moderate vacuum annealing at temperatures up to 600 °C and after ageing test of more than 200 h with several heating-cooling cycles are shown here.

Solar concentrators for advanced solar-dynamic power systems in space

NASA Technical Reports Server (NTRS)

Rockwell, Richard

1993-01-01

This report summarizes the results of a study performed by Hughes Danbury Optical Systems, HDOS, (formerly Perkin-Elmer) to design, fabricate, and test a lightweight (2 kg/sq M), self supporting, and highly reflective sub-scale concentrating mirror panel suitable for use in space. The HDOS panel design utilizes Corning's 'micro sheet' glass as the top layer of a composite honeycomb sandwich. This approach, whose manufacturability was previously demonstrated under an earlier NASA contract, provides a smooth (specular) reflective surface without the weight of a conventional glass panel. The primary result of this study is a point design and it's performance assessment.

An improved prism for use in laser resonators

NASA Astrophysics Data System (ADS)

Richards, J.

1981-08-01

The use of compound total internal reflection prisms rather than Porro prisms in polarisation coupled lasers is proposed. Performance advantages resulting from the use of these prisms include higher output without the need to bias the Pockels cell, ability to give a larger range of output coupling and independence of performance on the refractive index of the prism. In conventional Q-switched lasers the use of the prism at the Pockels cell end of the resonator instead of the usual 100% reflecting mirror also leads to some advantages including better hold-off, elimination of the need to bias the Pockels cell and insensitivity in one plane to angular misalignment.

Highly efficient coupler for dielectric slot waveguides and hybrid plasmonic waveguides

NASA Astrophysics Data System (ADS)

Yu, Jiyao; Ohtera, Yasuo; Yamada, Hirohito

2018-05-01

A compact, highly efficient optical coupler for dielectric slot waveguides and hybrid plasmonic waveguides based on transition layers (air slot grooves) was investigated. The power-coupling efficiency of 75% for the direct coupling case increased to 90% following the insertion of an intermediate section. By performing time-averaged Poynting vector analysis, we successfully separated the factors of transmission, reflection, and radiation at the coupler interface. We found that the insertion of optimal air grooves into the coupler structure contributed to the improvement of coupling performance. The proposed compact structure is characterized by a high transmission efficiency, low reflection, small length, and broad-band spectrum response.

Light budget and optimization strategies for display applications of dichroic nematic droplet/polymer films

NASA Astrophysics Data System (ADS)

Drzaic, Paul S.

1991-06-01

A detailed light budget is performed on reflective displays made from nematic droplet/polymer (NCAP) films incorporating dichroic dyes. It is shown that the radiance of these displays can be modeled using a simple scheme involving the convolution of the transmission spectra of the various components of the display. Comparisons are made between the relative importance of these optical elements in the display. It is shown that first-surface reflection (glare) is an important factor in reducing the optical performance of these displays, but that the effect of glare can be minimized through the proper choice of dye concentration.

How Would Ludwig Wittgenstein Have Performed in the Current South African Higher Education System?

ERIC Educational Resources Information Center

Le Grange, L.

2009-01-01

The pressure to perform has migrated from the corporate world into academe. Academics across the globe feel this pressure to perform, often expressed as "publish or perish". I reflect on the rising culture of performativity in recent decades and how it has penetrated South African universities. In doing so, I specifically look at the…

Computational Model-Based Prediction of Human Episodic Memory Performance Based on Eye Movements

NASA Astrophysics Data System (ADS)

Sato, Naoyuki; Yamaguchi, Yoko

Subjects' episodic memory performance is not simply reflected by eye movements. We use a ‘theta phase coding’ model of the hippocampus to predict subjects' memory performance from their eye movements. Results demonstrate the ability of the model to predict subjects' memory performance. These studies provide a novel approach to computational modeling in the human-machine interface.

Assessing Quality and Evaluating Performance in Higher Education: Worlds Apart or Complementary Views?

ERIC Educational Resources Information Center

Sarrico, Claudia S.; Rosa, Maria J.; Teixeira, Pedro N.; Cardoso, Margarida F.

2010-01-01

This paper reflects on quality assessment and performance evaluation in higher education, namely by analysing the insufficient link between those two aspects. We start by reviewing the current state of the art regarding different processes and mechanisms of quality assessment and performance evaluation and discuss some of the major issues…

Self-Reflection and Math Performance in an Online Learning Environment

ERIC Educational Resources Information Center

Choi, Jinnie; Walters, Alyssa; Hoge, Pat

2017-01-01

According to recent reports, K-12 full-time virtual school students have shown lower performance in math than their counterparts in brick-and-mortar schools. However, research is lacking in what kind of programmatic interventions virtual schools might be particularly well-suited to provide to improve math performance. Engaging students in…

The Effect of Student Self-Video of Performance on Clinical Skill Competency: A Randomised Controlled Trial

ERIC Educational Resources Information Center

Maloney, Stephen; Storr, Michael; Morgan, Prue; Ilic, Dragan

2013-01-01

Emerging technologies and student information technology literacy are enabling new methods of teaching and learning for clinical skill performance. Facilitating experiential practice and reflection on performance through student self-video, and exposure to peer benchmarks, may promote greater levels of skill competency. This study examines the…

The bioscouring performance of four polygalacturonase enzymes

USDA-ARS?s Scientific Manuscript database

Fourier Transform Infrared Attenuated Total Reflectance (FTIR-ATR) analyses of greige cotton fabrics bioscoured with a combination of ultrasound and endo- and exo-polygalacturonase enzymes obtained from Rhizopus sp. fungi were used in a fractional factorial design experiment to examine their perform...

Representing the Margins: Multimodal Performance as a Tool for Critical Reflection and Pedagogy

ERIC Educational Resources Information Center

Darvin, Ron

2015-01-01

This article discusses how drama as a multimodal performance can be a powerful means to represent marginalized identities and to stimulate critical thought among teachers and learners about material conditions of existence and social inequalities.

Relative performance evaluation of a custom-made near infrared reflectance instrument and two commercial instruments (Foss and ASD) in the nondestructive moisture content measurement of in-shell peanuts

USDA-ARS?s Scientific Manuscript database

A custom made Near Infrared Reflectance (NIR) spectroscope was used to determine the moisture content of in-shell peanuts of Virginia type peanuts. Peanuts were conditioned to different moisture levels between 6 and 26 % (wet basis) and samples from different moisture levels were separated into two...

Particle simulations on transport control in divertors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kashiwagi, Mieko; Ido, Shunji

1995-04-01

Particle orbit simulations are carried out to study the reflection of He ions recycled from a tokamak divertor by RF electric fields, which have the frequency close to ion cyclotron resonance frequency (ICRF). The performance of particle reflection and the requirement to the intensity of RF fields are studied. The control of He recycling by ICRF fields is found to be available. 4 refs., 4 figs.

Asphalt-Rubber SAMI (Stress-Absorbing Membrane Interlayers) Field Evaluation.

DTIC Science & Technology

1986-04-01

revealed that there was promise in using the material as an interlayer to prevent the reflection of cracks from an old pavement to a new asphalt -concrete...reflection cracking , and (2) that asphalt - rubber interlayers should be investigated in conjunction with conventional asphalt -concrete overlays. An... Asphalt -rubber samples were taken and tested and construction activities were documented. The performance has been monitored by conducting crack

Reflections on Speech Motor Control Based on Phonatory and DDK Tasks in Dysarthric Subjects with Lesions in Different Cerebellar Loci

ERIC Educational Resources Information Center

Vandana, V. P.

2007-01-01

There are very few acoustic studies reflecting on the localization of speech function within the different loci of the cerebellum. Task based performance profile of subjects with lesion in different cerebellar loci is not reported. Also, the findings on nonfocal cerebellar lesions cannot be generalized to lesions restricted to the cerebellum.…

Large area mapping of southwestern forest crown cover, canopy height, and biomass using the NASA Multiangle Imaging Spectro-Radiometer

Treesearch

Mark Chopping; Gretchen G. Moisen; Lihong Su; Andrea Laliberte; Albert Rango; John V. Martonchik; Debra P. C. Peters

2008-01-01

A rapid canopy reflectance model inversion experiment was performed using multi-angle reflectance data from the NASA Multi-angle Imaging Spectro-Radiometer (MISR) on the Earth Observing System Terra satellite, with the goal of obtaining measures of forest fractional crown cover, mean canopy height, and aboveground woody biomass for large parts of south-eastern Arizona...

Finding Communalities, Making Differences, Performing Masculinities: Reflections of Young Men on Military Service

ERIC Educational Resources Information Center

Lahelma, Elina

2005-01-01

In Finland more than 80% of the male population participates in military service. Going to the army is an important step in the transition to male adulthood and a period for further education. This paper explores reflections on the army of 20-year-old men, some of whom have it already behind them and some others with their military service…

A Reflection from the Classroom: Teaching Students to See from the Perspective of the Player

ERIC Educational Resources Information Center

Favila, Marina

2015-01-01

This personal reflection looks at the benefits of using performance pedagogy in the Shakespeare classroom, both in terms of a general understanding of the period and a student's personal connection to the text. Though the essay acknowledges our profession's ongoing dialogue in this area, it mostly seeks to look at how a student may change once she…

Practical Application of Polarization and Light Control for Reduction of Reflected Glare.

ERIC Educational Resources Information Center

Crouch, C. L.; Kaufman, J. E.

1963-01-01

The role of reflected glare and visual viewing angles in near task performance is discussed, and following statements are reported--(1) a worker at a desk normally assumes a position in which his eyes traverse an area of work extending from a point approximately vertically below his eyes to a point not more than 40 degrees from the vertical, (2) a…

Bidirectional reflectance distribution function measurements and analysis of retroreflective materials.

PubMed

Belcour, Laurent; Pacanowski, Romain; Delahaie, Marion; Laville-Geay, Aude; Eupherte, Laure

2014-12-01

We compare the performance of various analytical retroreflecting bidirectional reflectance distribution function (BRDF) models to assess how they reproduce accurately measured data of retroreflecting materials. We introduce a new parametrization, the back vector parametrization, to analyze retroreflecting data, and we show that this parametrization better preserves the isotropy of data. Furthermore, we update existing BRDF models to improve the representation of retroreflective data.

Airplane takeoff and landing performance monitoring system

NASA Technical Reports Server (NTRS)

Middleton, David B. (Inventor); Srivatsan, Raghavachari (Inventor); Person, Jr., Lee H. (Inventor)

1991-01-01

The invention is a real-time takeoff and landing performance monitoring system for an aircraft which provides a pilot with graphic and metric information to assist in decisions related to achieving rotation speed (V.sub.R) within the safe zone of a runway, or stopping the aircraft on the runway after landing or take-off abort. The system processes information in two segments: a pretakeoff segment and a real-time segment. One-time inputs of ambient conditions and airplane configuration information are used in the pretakeoff segment to generate scheduled performance data. The real-time segment uses the scheduled performance data, runway length data and transducer measured parameters to monitor the performance of the airplane throughout the takeoff roll. Airplane and engine performance deficiencies are detected and annunciated. A novel and important feature of this segment is that it updates the estimated runway rolling friction coefficient. Airplane performance predictions also reflect changes in head wind occurring as the takeoff roll progresses. The system provides a head-down display and a head-up display. The head-up display is projected onto a partially reflective transparent surface through which the pilot views the runway. By comparing the present performance of the airplane with a predicted nominal performance based upon given conditions, performance deficiencies are detected by the system.

Performance Evaluation of Machine Learning Methods for Leaf Area Index Retrieval from Time-Series MODIS Reflectance Data

PubMed Central

Wang, Tongtong; Xiao, Zhiqiang; Liu, Zhigang

2017-01-01

Leaf area index (LAI) is an important biophysical parameter and the retrieval of LAI from remote sensing data is the only feasible method for generating LAI products at regional and global scales. However, most LAI retrieval methods use satellite observations at a specific time to retrieve LAI. Because of the impacts of clouds and aerosols, the LAI products generated by these methods are spatially incomplete and temporally discontinuous, and thus they cannot meet the needs of practical applications. To generate high-quality LAI products, four machine learning algorithms, including back-propagation neutral network (BPNN), radial basis function networks (RBFNs), general regression neutral networks (GRNNs), and multi-output support vector regression (MSVR) are proposed to retrieve LAI from time-series Moderate Resolution Imaging Spectroradiometer (MODIS) reflectance data in this study and performance of these machine learning algorithms is evaluated. The results demonstrated that GRNNs, RBFNs, and MSVR exhibited low sensitivity to training sample size, whereas BPNN had high sensitivity. The four algorithms performed slightly better with red, near infrared (NIR), and short wave infrared (SWIR) bands than red and NIR bands, and the results were significantly better than those obtained using single band reflectance data (red or NIR). Regardless of band composition, GRNNs performed better than the other three methods. Among the four algorithms, BPNN required the least training time, whereas MSVR needed the most for any sample size. PMID:28045443

From feedback- to response-based performance monitoring in active and observational learning.

PubMed

Bellebaum, Christian; Colosio, Marco

2014-09-01

Humans can adapt their behavior by learning from the consequences of their own actions or by observing others. Gradual active learning of action-outcome contingencies is accompanied by a shift from feedback- to response-based performance monitoring. This shift is reflected by complementary learning-related changes of two ACC-driven ERP components, the feedback-related negativity (FRN) and the error-related negativity (ERN), which have both been suggested to signal events "worse than expected," that is, a negative prediction error. Although recent research has identified comparable components for observed behavior and outcomes (observational ERN and FRN), it is as yet unknown, whether these components are similarly modulated by prediction errors and thus also reflect behavioral adaptation. In this study, two groups of 15 participants learned action-outcome contingencies either actively or by observation. In active learners, FRN amplitude for negative feedback decreased and ERN amplitude in response to erroneous actions increased with learning, whereas observational ERN and FRN in observational learners did not exhibit learning-related changes. Learning performance, assessed in test trials without feedback, was comparable between groups, as was the ERN following actively performed errors during test trials. In summary, the results show that action-outcome associations can be learned similarly well actively and by observation. The mechanisms involved appear to differ, with the FRN in active learning reflecting the integration of information about own actions and the accompanying outcomes.

Performance Evaluation of Machine Learning Methods for Leaf Area Index Retrieval from Time-Series MODIS Reflectance Data.

PubMed

Wang, Tongtong; Xiao, Zhiqiang; Liu, Zhigang

2017-01-01

Leaf area index (LAI) is an important biophysical parameter and the retrieval of LAI from remote sensing data is the only feasible method for generating LAI products at regional and global scales. However, most LAI retrieval methods use satellite observations at a specific time to retrieve LAI. Because of the impacts of clouds and aerosols, the LAI products generated by these methods are spatially incomplete and temporally discontinuous, and thus they cannot meet the needs of practical applications. To generate high-quality LAI products, four machine learning algorithms, including back-propagation neutral network (BPNN), radial basis function networks (RBFNs), general regression neutral networks (GRNNs), and multi-output support vector regression (MSVR) are proposed to retrieve LAI from time-series Moderate Resolution Imaging Spectroradiometer (MODIS) reflectance data in this study and performance of these machine learning algorithms is evaluated. The results demonstrated that GRNNs, RBFNs, and MSVR exhibited low sensitivity to training sample size, whereas BPNN had high sensitivity. The four algorithms performed slightly better with red, near infrared (NIR), and short wave infrared (SWIR) bands than red and NIR bands, and the results were significantly better than those obtained using single band reflectance data (red or NIR). Regardless of band composition, GRNNs performed better than the other three methods. Among the four algorithms, BPNN required the least training time, whereas MSVR needed the most for any sample size.

UV reflectance is associated with environmental conditions in Palaearctic Pieris napi (Lepidoptera: Pieridae).

PubMed

Stella, David; Pecháček, Pavel; Meyer-Rochow, Victor Benno; Kleisner, Karel

2018-06-01

The subject of our investigation was the visual features of wing color with special focus on the UV reflectance in the green-veined white butterfly (Pieris napi). Previous studies had concluded that UV reflectance on dorsal wing surfaces is found only in the female P. napi. Based on UV sensitive photography, we analyzed a correlation between 12 geographic and environmental factors and UV reflectance patterns on 3 patches on the forewings of 407 P. napi specimens from the Palaearctic region. Results had shown that females significantly differ from males: they exhibit a 25% higher UV reflectance. To investigate whether and how UV reflectance levels on the forewings and hindwings of both sexes are influenced by the environment, we performed a principal component analysis (PCA) with several environmental variables. For several variables (in particular, latitude and longitude, mean annual temperature and precipitation, and temperature annual range and altitude), the generalized linear model (GLM) model revealed a significant correlation in both sexes. This suggests a link between UV reflectance levels and the environment and distribution of P. napi. We found that stronger UV reflectance is associated with generally more hostile environments and concluded that large-scale environmental factors influence the UV reflectance on the forewings of both male and female green-veined white butterflies. © 2016 Institute of Zoology, Chinese Academy of Sciences.

Reflection-artifact-free photoacoustic imaging using PAFUSion (photoacoustic-guided focused ultrasound)

NASA Astrophysics Data System (ADS)

Kuniyil Ajith Singh, Mithun; Jaeger, Michael; Frenz, Martin; Steenbergen, Wiendelt

2016-03-01

Reflection artifacts caused by acoustic inhomogeneities are a main challenge to deep-tissue photoacoustic imaging. Photoacoustic transients generated by the skin surface and superficial vasculature will propagate into the tissue and reflect back from echogenic structures to generate reflection artifacts. These artifacts can cause problems in image interpretation and limit imaging depth. In its basic version, PAFUSion mimics the inward travelling wave-field from blood vessel-like PA sources by applying focused ultrasound pulses, and thus provides a way to identify reflection artifacts. In this work, we demonstrate reflection artifact correction in addition to identification, towards obtaining an artifact-free photoacoustic image. In view of clinical applications, we implemented an improved version of PAFUSion in which photoacoustic data is backpropagated to imitate the inward travelling wave-field and thus the reflection artifacts of a more arbitrary distribution of PA sources that also includes the skin melanin layer. The backpropagation is performed in a synthetic way based on the pulse-echo acquisitions after transmission on each single element of the transducer array. We present a phantom experiment and initial in vivo measurements on human volunteers where we demonstrate significant reflection artifact reduction using our technique. The results provide a direct confirmation that reflection artifacts are prominent in clinical epi-photoacoustic imaging, and that PAFUSion can reduce these artifacts significantly to improve the deep-tissue photoacoustic imaging.

Reflective coating for near-infrared immersion gratings

NASA Astrophysics Data System (ADS)

Kuzmenko, Paul J.; Ikeda, Yuji; Kobayashi, Naoto; Mirkarimi, Paul B.; Alameda, Jennifer B.

2012-09-01

Achieving high reflectivity from an immersed grating facet can be challenging in the near infrared. The reflectivity of metallic coatings in common use, such as Al and Cr/Au, decrease with decreasing wavelength in the near IR. A layer of copper on ZnSe or ZnS should have a high, immersed reflectivity based on tabulated values of refractive index, but in fact performs poorly. We attribute this to a chemical reaction between the copper and the selenium or sulfur. A non-reactive intermediate layer can prevent this problem. Since reflectivity at an interface increases with increasing difference in refractive index, it is beneficial to choose an intermediate layer of low index. A further improvement is gained by adjusting the layer thickness so that reflections from the two interfaces of the intermediate layer add constructively. We sputtered 130 nm of SiO2 onto ZnSe and ZnS substrates followed by 200 nm of Cu. The copper was then coated with 5 nm of SiC as a protective capping layer. Immersed reflectivity measured shortly after coating exceeded 95% between 1500 and 1100 nm and exceeded 90% down to 850 nm. A repeat measurement after long term exposure to high humidity conditions showed no changes.

Color analysis and image rendering of woodblock prints with oil-based ink

NASA Astrophysics Data System (ADS)

Horiuchi, Takahiko; Tanimoto, Tetsushi; Tominaga, Shoji

2012-01-01

This paper proposes a method for analyzing the color characteristics of woodblock prints having oil-based ink and rendering realistic images based on camera data. The analysis results of woodblock prints show some characteristic features in comparison with oil paintings: 1) A woodblock print can be divided into several cluster areas, each with similar surface spectral reflectance; and 2) strong specular reflection from the influence of overlapping paints arises only in specific cluster areas. By considering these properties, we develop an effective rendering algorithm by modifying our previous algorithm for oil paintings. A set of surface spectral reflectances of a woodblock print is represented by using only a small number of average surface spectral reflectances and the registered scaling coefficients, whereas the previous algorithm for oil paintings required surface spectral reflectances of high dimension at all pixels. In the rendering process, in order to reproduce the strong specular reflection in specific cluster areas, we use two sets of parameters in the Torrance-Sparrow model for cluster areas with or without strong specular reflection. An experiment on a woodblock printing with oil-based ink was performed to demonstrate the feasibility of the proposed method.

Power reflectance testing in newborns and infants.

PubMed

Lima, Ticianna Garambone de Cerqueira; Becker, Helena Maria Gonçalves; Becker, Celso Gonçalves; Ferreira, Daniele Barreto da Cunha; Resende, Camilo Brandão de; Guimarães, Roberto Eustáquio Santos

2015-01-01

Auditory screening in newborns allows for detection of hearing problems early in life. However, middle ear diseases can make the diagnosis more difficult. To evaluate the power reflectance test as an indicator of the middle ear disease and to compare it to tympanometry. Case study evaluating 105 newborns and infants who participated in the audiology screening in 2013. The following exams were performed: transient otoacoustic emissions, power reflectance, and tympanometry. In the optoacoustic emission evaluation, approximately 95% of the subjects passed the test. The specificity of power reflectance in all frequencies studied ranged from 75.3% to 95.9%, and that of tympanometry at 1000Hz ranged from 83% to 87.2%; there was agreement among these exams. The outcome of power reflectance tests at 2000Hz and 3000Hz showed a correlation with tympanometry and otoacoustic emissions, and these were the most appropriate frequencies to determine middle ear disease through power reflectance measurement. It was also observed that values of power reflectance above reference levels suggested the presence of fluid in the middle ear, and thus a conductive hearing loss. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Visual and analytical strategies in spatial visualisation: perspectives from bilateral symmetry and reflection

NASA Astrophysics Data System (ADS)

Ramful, Ajay; Ho, Siew Yin; Lowrie, Tom

2015-12-01

This inquiry presents two fine-grained case studies of students demonstrating different levels of cognitive functioning in relation to bilateral symmetry and reflection. The two students were asked to solve four sets of tasks and articulate their reasoning in task-based interviews. The first participant, Brittany, focused essentially on three criteria, namely (1) equidistance, (2) congruence of sides and (3) `exactly opposite' as the intuitive counterpart of perpendicularity for performing reflection. On the other hand, the second participant, Sara, focused on perpendicularity and equidistance, as is the normative procedure. Brittany's inadequate knowledge of reflection shaped her actions and served as a validation for her solutions. Intuitively, her visual strategies took over as a fallback measure to maintain congruence of sides in the absence of a formal notion of perpendicularity. In this paper, we address some of the well-known constraints that students encounter in dealing with bilateral symmetry and reflection, particularly situations involving inclined line of symmetry. Importantly, we make an attempt to show how visual and analytical strategies interact in the production of a reflected image. Our findings highlight the necessity to give more explicit attention to the notion of perpendicularity in bilateral symmetry and reflection tasks.

Backscattering from targets residing in caustics resulting from ocean boundary interactions

NASA Astrophysics Data System (ADS)

Dzikowicz, Benjamin R.; Marston, Philip L.

2005-04-01

Detection of targets by backscatter in shallow water can be enhanced by interactions with ocean boundaries. A laboratory experiment is performed where a spherical target passes through an Airy caustic formed by a curved surface. When the target resides in the insonified region of the caustic there are two sets of multi-path rays: two pairs reflecting once off the surface (either to or from the target), and three reflecting twice off the surface (to and from the target). When a target moves across the caustic the singly reflected rays merge, as do the doubly reflected. With a longer tone burst the rays in each set overlap and the backscatter is greatly enhanced as the target moves into the insonified region. For a point target the singly reflected backscatter scales as an Airy function [B. R. Dzikowicz and P. L. Marston, J. Acoust. Soc. Am. 116, 2751-2757 (2004)], and the doubly reflected as the square of an Airy function. For a finite target the doubly reflected backscatter unfolds into a hyperbolic umbilic function. The arguments of the Airy and Hyperbolic Umbilic functions are calculated using the relative echo times of transient pulses. [Work supported by ONR.

Why credible propeller noise measurements are possible in the acoustically untreated NASA Lewis 8 ft by 6 ft wind tunnel

NASA Technical Reports Server (NTRS)

Dittmar, J. H.

1984-01-01

An explanation is presented for the lack of acoustic reflections in noise studies of propfan models in the NASA-Lewis 8 x 6 ft wind tunnel, where trials were run at Mach numbers 0.5-0.85. The highly directional propeller noise, i.e., mainly in the plane of rotation, experiences a convective effect due to the high subsonic axial Mach number. Reflected sounds are carried downstream, out of range of the acoustic sensors in the tunnel. Furthermore, reflected noise is less audible, and therefore does not affect measurements near peak values. It is suggested that some data contamination may occur below Mach 0.6, and that measurements be performed on higher harmonics generated by low level reflected noise.

Performance analysis of cross-seeding WDM-PON system using transfer matrix method

NASA Astrophysics Data System (ADS)

Simatupang, Joni Welman; Pukhrambam, Puspa Devi; Huang, Yen-Ru

2016-12-01

In this paper, a model based on the transfer matrix method is adopted to analyze the effects of Rayleigh backscattering and Fresnel multiple reflections on a cross-seeding WDM-PON system. As part of analytical approximation methods, this time-independent model is quite simple but very efficient when it is applied to various WDM-PON transmission systems, including the cross-seeding scheme. The cross seeding scheme is most beneficial for systems with low loop-back ONU gain or low reflection loss at the drop fiber for upstream data in bidirectional transmission. However for downstream data transmission, multiple reflections power could destroy the usefulness of the cross-seeding scheme when the reflectivity is high enough and the RN is positioned near OLT or close to ONU.

Estimating photosynthetic vegetation, non-photosynthetic vegetation and bare soil fractions using Landsat and MODIS data: Effects of site heterogeneity, soil properties and land cover

NASA Astrophysics Data System (ADS)

Guerschman, J. P.; Scarth, P.; McVicar, T.; Malthus, T. J.; Stewart, J.; Rickards, J.; Trevithick, R.; Renzullo, L. J.

2013-12-01

Vegetation fractional cover is a key indicator for land management monitoring, both in pastoral and agricultural settings. Maintaining adequate vegetation cover protects the soil from the effects of water and wind erosion and also ensures that carbon is returned to soil through decomposition. Monitoring vegetation fractional cover across large areas and continuously in time needs good remote sensing techniques underpinned by high quality ground data to calibrate and validate algorithms. In this study we used Landsat and MODIS reflectance data together with field measurements from 1476 observations across Australia to produce estimates of vegetation fractional cover using a linear unmixing technique. Specifically, we aimed at separating fractions of photosynthetic vegetation (PV), non-photosynthetic vegetation (NPV) and bare soil (B). We used Landsat reflectance averaged over a 3x3 pixel window representing the area actually measured on the ground and also a 'degraded' Landsat reflectance 40x40 pixel window to simulate the effect of a coarser sensor. Using these two Landsat reflectances we quantified the heterogeneity of each site. We used data from two MODIS-derived reflectance products: the Nadir BRDF-Adjusted surface Reflectance product (MCD43A4) and the MODIS 8-day surface reflectance (MOD09A1). We derived endmembers from the data and estimated fractional cover using a linear unmixing technique. Log transforms and band interaction terms were added to account for non-linearities in the spectral mixing. For each reflectance source we investigated if the residuals were correlated with site heterogeneity, soil colour, soil moisture and land cover type. As expected, the best model was obtained when Landsat data for a small region around each site was used. We obtained root mean square error (RMSE) values of 0.134, 0.175 and 0.153 for PV, NPV and B respectively. When we degraded the Landsat data to an area of ~1 km2 around each site the model performance decreased to RMSE of 0.142, 0.181 and 0.166 for PV, NPV and B. Using MODIS reflectance data (from the MCD43A4 and MOD09A1 products) we obtained similar results as when using the 'degraded' Landsat reflectance, with no significant differences between them. Model performance decreased (i.e. RMSE increased) with site heterogeneity when coarse resolution reflectance data was used. We did not find any evidence of soil colour or moisture influence on model performance. We speculate that the unmixing models may be insensitive to soil colour and/or that the soil moisture in the top few millimetres of soil, which influence reflectance in optical sensors, is decoupled from the soil moisture in the top layer (i.e. a few cm) as measured by passive microwave sensors or estimated by models. The models tended to overestimate PV in cropping areas, possibly due to a strong red/ near infrared signal in homogeneous crops which do not have a high green cover. This study sets the basis for an operational Landsat/ MODIS combined product which would benefit users with varying requirements of spatial, temporal resolution and latency and could potentially be applied to other regions in the world.

Controlling contamination in Mo/Si multilayer mirrors by Si surface capping modifications

NASA Astrophysics Data System (ADS)

Malinowski, Michael E.; Steinhaus, Chip; Clift, W. Miles; Klebanoff, Leonard E.; Mrowka, Stanley; Soufli, Regina

2002-07-01

The performance of Mo/Si multilayer mirrors (MLMs) used to reflect UV (EUV) radiation in an EUV + hydrocarbon (NC) vapor environment can be improved by optimizing the silicon capping layer thickness on the MLM in order to minimize the initial buildup of carbon on MLMs. Carbon buildup is undesirable since it can absorb EUV radiation and reduce MLM reflectivity. A set of Mo/Si MLMs deposited on Si wafers was fabricated such that each MLM had a different Si capping layer thickness ranging form 2 nm to 7 nm. Samples from each MLM wafer were exposed to a combination of EUV light + (HC) vapors at the Advanced Light Source (ALS) synchrotron in order to determine if the Si capping layer thickness affected the carbon buildup on the MLMs. It was found that the capping layer thickness had a major influence on this 'carbonizing' tendency, with the 3 nm layer thickness providing the best initial resistance to carbonizing and accompanying EUV reflectivity loss in the MLM. The Si capping layer thickness deposited on a typical EUV optic is 4.3 nm. Measurements of the absolute reflectivities performed on the Calibration and Standards beamline at the ALS indicated the EUV reflectivity of the 3 nm-capped MLM was actually slightly higher than that of the normal, 4 nm Si-capped sample. These results show that he use of a 3 nm capping layer represents an improvement over the 4 nm layer since the 3 nm has both a higher absolute reflectivity and better initial resistance to carbon buildup. The results also support the general concept of minimizing the electric field intensity at the MLM surface to minimize photoelectron production and, correspondingly, carbon buildup in a EUV + HC vapor environment.

Effects of Salinity on Leaf Spectral Reflectance and Biochemical Parameters of Nitrogen Fixing Soybean Plants (Glycine max L.)

NASA Astrophysics Data System (ADS)

Krezhova, Dora D.; Kirova, Elisaveta B.; Yanev, Tony K.; Iliev, Ilko Ts.

2010-01-01

Measurements of physiology and hyperspectral leaf reflectance were used to detect salinity stress in nitrogen fixing soybean plants. Seedlings were inoculated with suspension of Bradyrhizobium japonicum strain 273. Salinity was performed at the stage of 2nd-4th trifoliate expanded leaves by adding of NaCl in the nutrient solution of Helrigel in concentrations 40 mM and 80 mM. A comparative analysis was performed between the changes in the biochemical parameters - stress markers (phenols, proline, malondialdehyde, thiol groups), chlorophyll a and b, hydrogen peroxide, and leaf spectral reflectance in the spectral range 450-850 nm. The spectral measurements were carried out by an USB2000 spectrometer. The reflectance data of the control and treated plants in the red, green, red-edge and the near infrared ranges of the spectrum were subjected to statistical analysis. Statistically significant differences were found through the Student's t-criterion at the two NaCl concentrations in all of the ranges examined with the exception of the near infrared range at 40 mM NaCl concentration. Similar results were obtained through linear discriminant analysis. The tents of the phenols, malondialdehyde and chlorophyll a and b were found to decrease at both salinity treatments. In the spectral data this effect is manifested by decrease of the reflectance values in the green and red ranges. The contents of proline, hydrogen peroxide and thiol groups rose with the NaCl concentration increase. At 80 mM NaCl concentration the values of these markers showed a considerable increase giving evidence that the soybean plants were stressed in comparison with the control. This finding is in agreement with the results from the spectral reflectance analysis.

Absolute Radiometric Calibration of KOMPSAT-3A

NASA Astrophysics Data System (ADS)

Ahn, H. Y.; Shin, D. Y.; Kim, J. S.; Seo, D. C.; Choi, C. U.

2016-06-01

This paper presents a vicarious radiometric calibration of the Korea Multi-Purpose Satellite-3A (KOMPSAT-3A) performed by the Korea Aerospace Research Institute (KARI) and the Pukyong National University Remote Sensing Group (PKNU RSG) in 2015.The primary stages of this study are summarized as follows: (1) A field campaign to determine radiometric calibrated target fields was undertaken in Mongolia and South Korea. Surface reflectance data obtained in the campaign were input to a radiative transfer code that predicted at-sensor radiance. Through this process, equations and parameters were derived for the KOMPSAT-3A sensor to enable the conversion of calibrated DN to physical units, such as at-sensor radiance or TOA reflectance. (2) To validate the absolute calibration coefficients for the KOMPSAT-3A sensor, we performed a radiometric validation with a comparison of KOMPSAT-3A and Landsat-8 TOA reflectance using one of the six PICS (Libya 4). Correlations between top-of-atmosphere (TOA) radiances and the spectral band responses of the KOMPSAT-3A sensors at the Zuunmod, Mongolia and Goheung, South Korea sites were significant for multispectral bands. The average difference in TOA reflectance between KOMPSAT-3A and Landsat-8 image over the Libya 4, Libya site in the red-green-blue (RGB) region was under 3%, whereas in the NIR band, the TOA reflectance of KOMPSAT-3A was lower than the that of Landsat-8 due to the difference in the band passes of two sensors. The KOMPSAT-3Aensor includes a band pass near 940 nm that can be strongly absorbed by water vapor and therefore displayed low reflectance. Toovercome this, we need to undertake a detailed analysis using rescale methods, such as the spectral bandwidth adjustment factor.

Eight-channel time-resolved tissue oximeter for functional muscle studies

NASA Astrophysics Data System (ADS)

Cubeddu, Rinaldo; Biscotti, Giovanni; Pifferi, Antonio; Taroni, Paola; Torricelli, Alessandro; Ferrari, Marco; Quaresima, Valentina

2003-07-01

A portable instrument for tissue oximetry based on time-resolved reflectance spectroscopy was developed. The output pulses of 2 laser diodes (683 and 785 nm, 80 MHz pulse repetition rate, 1 mW average power, 100 ps FWHM) are delayed and coupled into a multimode graded-index fiber (50/125 μm and injected into the tissue. The reflectance photons are collected by 8 independent 1 mm fibers and detected by a 16-anode photomultiplier. A time-correlated single photon counting PC board is used for the parallel acquisition of the curves. Simultaneous estimate of the transport scattering and absorption coefficients is achieved by best fitting of time-resolved reflectance curves with a standard model of Diffusion Theory. The performances of the system were tested on phantoms in terms of stability, reproducibility among channels, and accuracy in the determination of the optical properties. Preliminary in vivo measurements were performed on healthy volunteers to monitor spatial changes in calf (medical and lateral gastrocnemius) oxygen hemoglobin saturation and blood volume during dynamic plantar flexion exercise.

Self-assembled nanotextures impart broadband transparency to glass windows and solar cell encapsulants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liapis, Andreas C.; Rahman, Atikur; Black, Charles T.

Most optoelectronic components and consumer display devices require glass or plastic covers for protection against the environment. Optical reflections from these encapsulation layers can degrade the device performance or lessen the user experience. In this paper, we use a highly scalable self-assembly based approach to texture glass surfaces at the nanoscale, reducing reflections by such an extent so as to make the glass essentially invisible. Our nanotextures provide broadband antireflection spanning visible and infrared wavelengths (450–2500 nm) that is effective even at large angles of incidence. This technology can be used to improve the performance of photovoltaic devices by eliminatingmore » reflection losses, which can be as much as 8% for glass encapsulated cells. In contrast, solar cells encapsulated with nanotextured glass generate the same photocurrent as when operated without a cover. Finally, ultra-transparent windows having surface nanotextures on both sides can withstand three times more optical fluence than commercial broadband antireflection coatings, making them useful for pulsed laser applications.« less

Optical characterization of agricultural pest insects: a methodological study in the spectral and time domains

NASA Astrophysics Data System (ADS)

Li, Y. Y.; Zhang, H.; Duan, Z.; Lian, M.; Zhao, G. Y.; Sun, X. H.; Hu, J. D.; Gao, L. N.; Feng, H. Q.; Svanberg, S.

2016-08-01

Identification of agricultural pest insects is an important aspect in insect research and agricultural monitoring. We have performed a methodological study of how spectroscopic techniques and wing-beat frequency analysis might provide relevant information. An optical system based on the combination of close-range remote sensing and reflectance spectroscopy was developed to study the optical characteristics of different flying insects, collected in Southern China. The results demonstrate that the combination of wing-beat frequency assessment and reflectance spectral analysis has the potential to successfully differentiate between insect species. Further, studies of spectroscopic characteristics of fixed specimen of insects, also from Central China, showed the possibility of refined agricultural pest identification. Here, in addition to reflectance recordings also laser-induced fluorescence spectra were investigated for all the species of insects under study and found to provide complementary information to optically distinguish insects. In order to prove the practicality of the techniques explored, clearly fieldwork aiming at elucidating the variability of parameters, even within species, must be performed.

Development of a high efficiency thin silicon solar cell. [fabrication and stability tests

NASA Technical Reports Server (NTRS)

Lindmayer, J.

1976-01-01

One hundred thin (120 microns to 260 microns) silicon-aluminum solar cells were fabricated and tested. Silicon slices were prepared, into which an aluminum alloy was evaporated over a range of temperatures and times. Antireflection coatings of tantalum oxide were applied to the cells. Reflectance of the silicon-aluminum interfaces was correlated to alloy temperature (graphs are shown). Optical measurements of the rear surface-internal reflectance of the cells were performed using a Beckman spectrophotometer. An improved gridline pattern was evaluated and stability tests (thermal cycling tests) were performed. Results show that: (1) a high-index, high-transmittance antireflection coating was obtained; (2) the improved metallization of the cells gave a 60 percent rear surface-internal reflectance, and the cells displayed excellent fill factors and blue response of the spectrum; (3) an improved gridline pattern (5 micron linewidths compared to 13 micron linewidths) resulted in a 1.3 percent improvement in short circuit currents; and (4) the stability tests showed no change in cell properties.

An improved driving waveform reference grayscale of electrophoretic displays

NASA Astrophysics Data System (ADS)

Wang, Li; Yi, Zichuan; Peng, Bao; Zhou, Guofu

2015-10-01

Driving waveform is an important component for gray scale display on the electrophoretic display (EPD). In the traditional driving waveform, a white reference gray scale is formed before writing a new image. However, the reflectance value can not reach agreement in each gray scale transformation. In this paper, a new driving waveform, which has a short waiting time after the formation of reference gray scale, is proposed to improve the consistency of reference gray scale. Firstly, the property of the particles in the microcapsule is analyzed and the change of the EPD reflectance after the white reference gray scale formation is studied. Secondly, the reflectance change curve is fitted by using polynomial and the duration of the waiting time is determined. Thirdly, a set of the new driving waveform is designed by using the rule of DC balance and some real E-ink commercial EPDs are used to test the performance. Experimental results show that the effect of the new driving waveform has a better performance than traditional waveforms.

Self-assembled nanotextures impart broadband transparency to glass windows and solar cell encapsulants

DOE PAGES

Liapis, Andreas C.; Rahman, Atikur; Black, Charles T.

2017-10-30

Most optoelectronic components and consumer display devices require glass or plastic covers for protection against the environment. Optical reflections from these encapsulation layers can degrade the device performance or lessen the user experience. In this paper, we use a highly scalable self-assembly based approach to texture glass surfaces at the nanoscale, reducing reflections by such an extent so as to make the glass essentially invisible. Our nanotextures provide broadband antireflection spanning visible and infrared wavelengths (450–2500 nm) that is effective even at large angles of incidence. This technology can be used to improve the performance of photovoltaic devices by eliminatingmore » reflection losses, which can be as much as 8% for glass encapsulated cells. In contrast, solar cells encapsulated with nanotextured glass generate the same photocurrent as when operated without a cover. Finally, ultra-transparent windows having surface nanotextures on both sides can withstand three times more optical fluence than commercial broadband antireflection coatings, making them useful for pulsed laser applications.« less

Distortion correction and cross-talk compensation algorithm for use with an imaging spectrometer based spatially resolved diffuse reflectance system

NASA Astrophysics Data System (ADS)

Cappon, Derek J.; Farrell, Thomas J.; Fang, Qiyin; Hayward, Joseph E.

2016-12-01

Optical spectroscopy of human tissue has been widely applied within the field of biomedical optics to allow rapid, in vivo characterization and analysis of the tissue. When designing an instrument of this type, an imaging spectrometer is often employed to allow for simultaneous analysis of distinct signals. This is especially important when performing spatially resolved diffuse reflectance spectroscopy. In this article, an algorithm is presented that allows for the automated processing of 2-dimensional images acquired from an imaging spectrometer. The algorithm automatically defines distinct spectrometer tracks and adaptively compensates for distortion introduced by optical components in the imaging chain. Crosstalk resulting from the overlap of adjacent spectrometer tracks in the image is detected and subtracted from each signal. The algorithm's performance is demonstrated in the processing of spatially resolved diffuse reflectance spectra recovered from an Intralipid and ink liquid phantom and is shown to increase the range of wavelengths over which usable data can be recovered.

Using Neural Networks to Improve the Performance of Radiative Transfer Modeling Used for Geometry Dependent Surface Lambertian-Equivalent Reflectivity Calculations

NASA Technical Reports Server (NTRS)

Fasnacht, Zachary; Qin, Wenhan; Haffner, David P.; Loyola, Diego; Joiner, Joanna; Krotkov, Nickolay; Vasilkov, Alexander; Spurr, Robert

2017-01-01

Surface Lambertian-equivalent reflectivity (LER) is important for trace gas retrievals in the direct calculation of cloud fractions and indirect calculation of the air mass factor. Current trace gas retrievals use climatological surface LER's. Surface properties that impact the bidirectional reflectance distribution function (BRDF) as well as varying satellite viewing geometry can be important for retrieval of trace gases. Geometry Dependent LER (GLER) captures these effects with its calculation of sun normalized radiances (I/F) and can be used in current LER algorithms (Vasilkov et al. 2016). Pixel by pixel radiative transfer calculations are computationally expensive for large datasets. Modern satellite missions such as the Tropospheric Monitoring Instrument (TROPOMI) produce very large datasets as they take measurements at much higher spatial and spectral resolutions. Look up table (LUT) interpolation improves the speed of radiative transfer calculations but complexity increases for non-linear functions. Neural networks perform fast calculations and can accurately predict both non-linear and linear functions with little effort.

Strategic Resource Use for Learning: A Self-Administered Intervention That Guides Self-Reflection on Effective Resource Use Enhances Academic Performance.

PubMed

Chen, Patricia; Chavez, Omar; Ong, Desmond C; Gunderson, Brenda

2017-06-01

Many educational policies provide learners with more resources (e.g., new learning activities, study materials, or technologies), but less often do they address whether students are using these resources effectively. We hypothesized that making students more self-reflective about how they should approach their learning with the resources available to them would improve their class performance. We designed a novel Strategic Resource Use intervention that students could self-administer online and tested its effects in two cohorts of a college-level introductory statistics class. Before each exam, students randomly assigned to the treatment condition strategized about which academic resources they would use for studying, why each resource would be useful, and how they would use their resources. Students randomly assigned to the treatment condition reported being more self-reflective about their learning throughout the class, used their resources more effectively, and outperformed students in the control condition by an average of one third of a letter grade in the class.

Scientific information repository assisting reflectance spectrometry in legal medicine.

PubMed

Belenki, Liudmila; Sterzik, Vera; Bohnert, Michael; Zimmermann, Klaus; Liehr, Andreas W

2012-06-01

Reflectance spectrometry is a fast and reliable method for the characterization of human skin if the spectra are analyzed with respect to a physical model describing the optical properties of human skin. For a field study performed at the Institute of Legal Medicine and the Freiburg Materials Research Center of the University of Freiburg, a scientific information repository has been developed, which is a variant of an electronic laboratory notebook and assists in the acquisition, management, and high-throughput analysis of reflectance spectra in heterogeneous research environments. At the core of the repository is a database management system hosting the master data. It is filled with primary data via a graphical user interface (GUI) programmed in Java, which also enables the user to browse the database and access the results of data analysis. The latter is carried out via Matlab, Python, and C programs, which retrieve the primary data from the scientific information repository, perform the analysis, and store the results in the database for further usage.

Self-assembled nanotextures impart broadband transparency to glass windows and solar cell encapsulants

NASA Astrophysics Data System (ADS)

Liapis, Andreas C.; Rahman, Atikur; Black, Charles T.

2017-10-01

Most optoelectronic components and consumer display devices require glass or plastic covers for protection against the environment. Optical reflections from these encapsulation layers can degrade the device performance or lessen the user experience. Here, we use a highly scalable self-assembly based approach to texture glass surfaces at the nanoscale, reducing reflections by such an extent so as to make the glass essentially invisible. Our nanotextures provide broadband antireflection spanning visible and infrared wavelengths (450-2500 nm) that is effective even at large angles of incidence. This technology can be used to improve the performance of photovoltaic devices by eliminating reflection losses, which can be as much as 8% for glass encapsulated cells. In contrast, solar cells encapsulated with nanotextured glass generate the same photocurrent as when operated without a cover. Ultra-transparent windows having surface nanotextures on both sides can withstand three times more optical fluence than commercial broadband antireflection coatings, making them useful for pulsed laser applications.