Fast full‐color reflective display via photoluminescent enhancement

Reflective displays are advantageous in applications requiring low power or daylight readability. However, there are no low‐cost reflective technologies capable of displaying bright colors. By employing photoluminescence to more efficiently use ambient light, we created a prototype display that provides bright, full color in a simple, low‐cost architecture. This prototype includes a novel electrokinetic shutter, a layer that incorporates patterned luminescent red, green, and blue sub‐pixel elements, and a novel optical out‐coupling scheme. The luminescent elements convert otherwise‐wasted portions of the incident spectrum to light in the desired color band, resulting in improved color saturation and lightness. This prototype provides a color gamut that is superior to competing reflective display technologies that utilize color filters in single‐layer side‐by‐side sub‐pixel architectures. The current prototype is capable of switching in <0.5 s; future displays based on an alternative electro‐optic shutter technology should achieve video rate operation. A transflective version of this technology has also been prototyped. The transflective version utilizes its backlight with a power efficiency that is at least three times that of a conventional liquid crystal display. These photoluminescence‐based technologies enable a host of applications ranging from low‐power mobile products and retail pricing signage to daylight readable signage for outdoor advertising segments.     

Invasive species detection in Hawaiian rainforests using airborne imaging spectroscopy and LiDAR

Remote sensing of invasive species is a critical component of conservation and management efforts, but reliable methods for the detection of invaders have not been widely established. In Hawaiian forests, we recently found that invasive trees often have hyperspectral signatures unique from that of native trees, but mapping based on spectral reflectance properties alone is confounded by issues of canopy senescence and mortality, intra- and inter-canopy gaps and shadowing, and terrain variability. We deployed a new hybrid airborne system combining the Carnegie Airborne Observatory (CAO) small-footprint light detection and ranging (LiDAR) system with the Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) to map the three-dimensional spectral and structural properties of Hawaiian forests. The CAO-AVIRIS systems and data were fully integrated using in-flight and post-flight fusion techniques, facilitating an analysis of forest canopy properties to determine the presence and abundance of three highly invasive tree species in Hawaiian rainforests.

The LiDAR sub-system was used to model forest canopy height and top-of-canopy surfaces; these structural data allowed for automated masking of forest gaps, intra- and inter-canopy shadows, and minimum vegetation height in the AVIRIS images. The remaining sunlit canopy spectra were analyzed using spatially-constrained spectral mixture analysis. The results of the combined LiDAR-spectroscopic analysis highlighted the location and fractional abundance of each invasive tree species throughout the rainforest sites. Field validation studies demonstrated < 6.8% and < 18.6% error rates in the detection of invasive tree species at  7 m² and  2 m² minimum canopy cover thresholds. Our results show that full integration of imaging spectroscopy and LiDAR measurements provides enormous flexibility and analytical potential for studies of terrestrial ecosystems and the species contained within them.     

Influence of Cr3+ on yellowish-green UC emission and energy transfer of Er3+/Cr3+/Yb3+ tri-doped zinc silicate glasses

In this paper, we study the influence of Cr³⁺ on yellowish-green upconversion (UC) emission and the energy transfer (ET) of Er³⁺/Cr³⁺/Yb³⁺ tri-doped in SiO₂–ZnO–Na₂O–La₂O₃ (SZNL) zinc silicate glasses under excitation of the 980 nm laser diode (LD). The influence of Cr³⁺ on enhancing the red UC emission of Er³⁺/Cr³⁺/Yb³⁺ tri-doped in SiO₂–ZnO–Na₂O–La₂O₃ zinc silicate glasses under the excitation of 980nm LD was also investigated. The ET processes between Yb³⁺, Cr^3+, and Er³⁺, together with the combination of Yb³⁺-Cr³⁺-Er³⁺, which led to the green UC emission intensity of Er³⁺/Cr³⁺/Yb³⁺ tri-doped in SiO₂–ZnO–Na₂O–La₂O₃ zinc silicate glasses bands centered at ~546 nm have been significantly enhanced. By increasing the concentration of Cr³⁺ from 0 up to 5 mol.%, we can locate the Commission Internationale de l'éclairage (CIE) 1931 (x; y) chromaticity coordinates for UC emissions of Er³⁺/Cr³⁺/Yb³⁺ tri-doped in the central position of the yellowish-green color region of CIE 1931 chromaticity diagram. Besides, the ET processes between the Yb³⁺, Cr³⁺, and Er³⁺ are also proposed and discussed.     

Prospective predictors of posttraumatic stress disorder symptoms: Direct and mediated relations.

This study assessed the relations between pretrauma risk (neuroticism, negative affect, prior distress) and protective (self-esteem, optimism) factors and posttraumatic stress disorder (PTSD) symptoms and potential mediators (subjective event-related distress, unsupportive social interactions, perceived control) of those relations. Students (N = 1,528) at four U.S. universities completed online surveys assessing pretrauma risk and protective factors at Time 1 (T1); 84% (N = 1,281) completed a survey 2 months later (T2). PTSD symptoms and the three potential mediators were assessed among those who experienced potentially traumatic events between T1 and T2 (n = 264). PTSD symptoms related to prior traumas were controlled in all analyses. In structural equation modeling (SEM) analyses, the relation between risk factors and PTSD symptoms was mediated by unsupportive social interactions. Protective factors did not independently predict PTSD symptoms when risk factors also were included in the SEM models. Implications for research and practice are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Responsible Use of Computer Technology by Engineers

Computer technology has given rise to new forms and modes of project failures in the construction industry. Engineers are prime targets of claims to recover financial losses caused by these computer-provoked failures. Thus, engineers should have a basic understanding of their legal responsibilities associated with the use of computers. In order to foster such an understanding, this paper discusses examples of how computer accidents can occur in the construction industry and examines the legal ramifications to engineers, discusses potential recourse theories engineers may have against hardware and software vendors or insurers, and identifies measures engineers can take to reduce the likelihood of an accident and the corresponding likelihood of a claim.     

Quantification of tool wear using white light interferometry and three-dimensional computational metrology

Although several wear modes can result from machining, the most common tend to be what are referred to as flank wear and crater wear. Flank wear can be easily measured directly from images of a worn cutting tool, and this is the typical method used to quantify the condition of a tool. On the other hand, crater wear is difficult to quantify, and thus has typically been treated in a qualitative manner. The inability to characterize and compare the two wear modes in a quantitative way is an increasingly important problem as the precision of machining operations improves and cutting moves almost exclusively to the nose radius of cutting tools. This paper introduces a new approach to this problem by proposing a technique to quantify both wear modes for direct comparison. The technique measures the volumetric wear loss in the two regions by comparing three-dimensional wear data obtained by white light interferometry with ideal representations of unworn cutting tools. The resulting wear measurements are compared and related to changes in the cutting process, specifically increases in cutting forces and changes in the topography of machined surfaces.     

Solution Enhancement and Post-enhancement Storage Effects on the Quality, Sensory, and Retail Display Characteristics of Beef Triceps Brachii Muscles

Beef triceps brachii muscles (6 d postmortem; n= 15; muscle sections n= 45) were sectioned into 3rds and allocated to 1 of 3 treatments. The treatments were untreated (CNT), or injected at a 12% pump rate with either tap water‐only (H₂O) or a solution comprising tetrasodium pyrophosphate and sodium chloride (TSPP/ NaCl) at 0.4% and 1.0% target final product weight concentrations, respectively. Each muscle (comprising all 3 treatments) was then allocated to 2, 14, or 28 d of vacuum‐packaged 1°C storage. Purge losses during storage were greatest (P < 0.05) for H₂O muscles and least (P < 0.05) for TSPP/NaCl muscles. Purge losses also increased (P < 0.05) from 2 d to 14 d of storage. Steaks enhanced with TSPP/NaCl had less (P < 0.05) free water and lower (P < 0.05) cooking losses than either CNT or H₂O steaks. Storage duration did not affect (P > 0.05) Warner‐Bratzler shear force (WBS) or sensory tenderness, but juiciness decreased (P < 0.05) with increased storage duration. While storage duration did not impact (P > 0.05) instrumental color characteristics, aerobic plate counts generally increased during storage. The TSPP/NaCl steaks had lower (P < 0.05) WBS values and improved (P < 0.05) sensory tenderness and juiciness characteristics compared with CNT or H₂O steaks. While CNT steaks had greater (P < 0.05) L* values (lightness) than TSPP/NaCl steaks, TSPP/NaCl steaks had similar (P > 0.05) oxymyoglobin proportions (630/580 nm) and a* values (redness) as CNT steaks. These results suggest enhancement with TSPP/NaCl can improve triceps brachii yield and palatability characteristics. Increased post‐enhancement storage did not impact or worsened palatability while increasing purge losses, suggesting general deleterious effects of increased postmortem storage for this muscle.     

Are genetically informed designs genetically informative? Comment on McGue, Elkins, Walden, and Iacono (2005) and quantitative behavioral genetics.

M. McGue, I. Elkins, B. Walden, and W. G. Iacono (see record 2005-14938-011) presented the findings from a twin study examining the relative contributions of genetic and environmental factors to the developmental trajectories of parent-adolescent relationships. From a behavioral genetics perspective, this study is well conceptualized, is well implemented, and raises some interesting developmental questions. Yet, the classic twin methodology and heritability estimates obfuscate the dynamic gene-ecology transactions that underlie these social developmental trajectories. There is a growing divide between the findings of quantitative behavioral genetics, with its foundational estimate of a statistical genetic influence, and developmental molecular genetics. This comment provides a brief overview of this divide and its implications for the findings of McGue et al. as well as quantitative behavioral genetics more broadly. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On proportional fairness of uplink spectral efficiency in cell‐free massive MIMO systems

This paper is concerned with the proportional fairness (PF) of the spectral efficiency (SE) maximization of uplinks in a cell‐free (CF) massive multiple‐input multiple‐output (MIMO) system in which a large number of single‐antenna access points (APs) connected to a central processing unit (CPU) serve many single‐antenna users. To detect the user signals, the APs use matched filters based on the local channel state information while the CPU deploys receiver filters based on knowledge of channel statistics. We devise the maximization problem of the SE PF, which maximizes the sum of the logarithm of the achievable user rates, as a jointly nonconvex optimization problem of receiver filter coefficients and user power allocation subject to user power constraints. To handle the challenges associated with the nonconvexity of the formulated design problem, we develop an iterative algorithm by alternatively finding optimal filter coefficients at the CPU and transmit powers at the users. While the filter coefficient design is formulated as a generalized eigenvalue problem, the power allocation problem is addressed by a gradient projection (GP) approach. Simulation results show that the SE PF maximization not only offers approximately the achievable sum rates as compared to the sum‐rate maximization but also provides an improved trade‐off between the user rate fairness and the achievable sum rate.