On the design of a (H)EV steerable warning device using acoustic beam forming and advanced numerical acoustic simulation

This paper describes the simulation-based design methodology used in the eVADER project for the development of targeted acoustic warning devices for increased detectability of Hybrid and Electric Vehicles (HEVs) while, at the same time, reducing urban noise pollution. A key component of this system is an external warning signal generator capable of projecting the warning signals to a contained area in front of the vehicle where potential at-risk situations are detected. Using acoustic beam forming principles a suitable warning strategy and an initial layout for realizing such a system is defined. Starting from this information, acoustic Finite and Boundary Element models of the transducer array allow assessing more realistically the performance impact of the system integration and of the most critical changes in the acoustic environment in which the signal generator needs to operate

Evolution of Linear Absorption and Nonlinear Optical Properties in V-Shaped Ruthenium(II)-Based Chromophores

In this article, we describe a series of complexes with electron-rich cis-{Ru^(II)(NH_3)_4}^(2+) centers coordinated to two pyridyl ligands bearing N-methyl/arylpyridinium electron-acceptor groups. These V-shaped dipolar species are new, extended members of a class of chromophores first reported by us (Coe, B. J. et al. J. Am. Chem. Soc. 2005, 127, 4845−4859). They have been isolated as their PF_6− salts and characterized by using various techniques including ^1H NMR and electronic absorption spectroscopies and cyclic voltammetry. Reversible Ru^(III/II) waves show that the new complexes are potentially redox-switchable chromophores. Single crystal X-ray structures have been obtained for four complex salts; three of these crystallize noncentrosymmetrically, but with the individual molecular dipoles aligned largely antiparallel. Very large molecular first hyperpolarizabilities β have been determined by using hyper-Rayleigh scattering (HRS) with an 800 nm laser and also via Stark (electroabsorption) spectroscopic studies on the intense, visible d → π^* metal-to-ligand charge-transfer (MLCT) and π → π^* intraligand charge-transfer (ILCT) bands. The latter measurements afford total nonresonant β_0 responses as high as ca. 600 × 10^(−30) esu. These pseudo-C_(2v) chromophores show two substantial components of the β tensor, β_(zzz) and β_(zyy), although the relative significance of these varies with the physical method applied. According to HRS, β_(zzz) dominates in all cases, whereas the Stark analyses indicate that β_(zyy) is dominant in the shorter chromophores, but β_(zzz) and β_(zyy) are similar for the extended species. In contrast, finite field calculations predict that β_(zyy) is always the major component. Time-dependent density functional theory calculations predict increasing ILCT character for the nominally MLCT transitions and accompanying blue-shifts of the visible absorptions, as the ligand π-systems are extended. Such unusual behavior has also been observed with related 1D complexes (Coe, B. J. et al. J. Am. Chem. Soc. 2004, 126, 3880−3891)

Solar Sail Propulsion: Enabling New Capabilities for Heliophysics

Solar sails can play a critical role in enabling solar and heliophysics missions. Solar sail technology within NASA is currently at 80% of TRL-6, suitable for an in-flight technology demonstration. It is conceivable that an initial demonstration could carry scientific payloads that, depending on the type of mission, are commensurate with the goals of the three study panels of the 2010 Heliophysics Survey. Follow-on solar sail missions, leveraging advances in solar sail technology to support Heliophysics Survey goals, would then be feasible. This white paper reports on a sampling of missions enabled by solar sails, the current state of the technology, and what funding is required to advance the current state of technology such that solar sails can enable these mission

Transient exposure to low levels of insecticide affects metabolic networks of honeybee larvae

The survival of a species depends on its capacity to adjust to changing environmental conditions, and new stressors. Such new, anthropogenic stressors include the neonicotinoid class of crop-protecting agents, which have been implicated in the population declines of pollinating insects, including honeybees (Apis mellifera). The low-dose effects of these compounds on larval development and physiological responses have remained largely unknown. Over a period of 15 days, we provided syrup tainted with low levels (2 µg/L−1) of the neonicotinoid insecticide imidacloprid to beehives located in the field. We measured transcript levels by RNA sequencing and established lipid profiles using liquid chromatography coupled with mass spectrometry from worker-bee larvae of imidacloprid-exposed (IE) and unexposed, control (C) hives. Within a catalogue of 300 differentially expressed transcripts in larvae from IE hives, we detect significant enrichment of genes functioning in lipid-carbohydrate-mitochondrial metabolic networks. Myc-involved transcriptional response to exposure of this neonicotinoid is indicated by overrepresentation of E-box elements in the promoter regions of genes with altered expression. RNA levels for a cluster of genes encoding detoxifying P450 enzymes are elevated, with coordinated downregulation of genes in glycolytic and sugar-metabolising pathways. Expression of the environmentally responsive Hsp90 gene is also reduced, suggesting diminished buffering and stability of the developmental program. The multifaceted, physiological response described here may be of importance to our general understanding of pollinator health. Muscles, for instance, work at high glycolytic rates and flight performance could be impacted should low levels of this evolutionarily novel stressor likewise induce downregulation of energy metabolising genes in adult pollinators

Correlation Between Bulk Material Defects and Spectroscopic Response in Cadmium Zinc Telluride Detectors

One of the critical challenges for large area cadmium zinc telluride (CdZnTe) detector arrays is obtaining material capable of uniform imaging and spectroscopic response. Two complementary nondestructive techniques for characterizing bulk CdZnTe have been developed to identify material with a uniform response. The first technique, infrared transmission imaging, allows for rapid visualization of bulk defects. The second technique, x-ray spectral mapping, provides a map of the material spectroscopic response when it is configured as a planar detector. The two techniques have been used to develop a correlation between bulk defect type and detector performance. The correlation allows for the use of infrared imaging to rapidly develop wafer mining maps. The mining of material free of detrimental defects has the potential to dramatically increase the yield and quality of large area CdZnTe detector arrays

Plugged hexagonal templated silica: a unique micro-and mesoporous composite material with internal silica nanocapsules †

We describe in this paper the development of plugged hexagonal templated silicas (PHTS) which are hexagonally ordered materials, with internal microporous silica nanocapsules; they have a combined micro-and mesoporosity and a tuneable amount of both open and encapsulated mesopores and are much more stable than other tested micellar templated structures. Researchers of Mobil published in 1992 a breakthrough report on the synthesis of ordered mesoporous silica materials. All synthesised materials exhibit the typical X-Ray diffraction patterns of the 2D hexagonal pore ordering in the p6mm space group. 2 † The 77 K nitrogen isotherm in High resolution TEM measurements confirm this model. § The rather thick walls (~4 nm) of the large cylindrical mesopores are perforated with micropores. Moreover, the cylindrical mesopores themselves are 'plugged' with amorphous silica nanocapsules, which are also microporous. These nanocapsules are created by the large excess of the silica source (TEOS) that is used in the synthesis and by rapid hydrolysis of the silicon alkoxide at the very low pH used. The micropores in the silica walls can be explained by the penetration of hydrophilic poly(ethyleneoxide) chains of the triblock copolymer in the silica wall, as already suggested by Kruk et al. 7 The microporosity of the plugs may have a different origin. It is known that Pluronic triblock copolymers are in fact polydisperse mixtures of several triblock copolymers with a wide range of molecular weights, and that they contain appreciable amounts of diblock copolymers and even free PO chains. Some † Electronic supplementary information (ESI) available

Plugged hexagonal templated silica: a unique micro-and mesoporous composite material with internal silica nanocapsules †

We describe in this paper the development of plugged hexagonal templated silicas (PHTS) which are hexagonally ordered materials, with internal microporous silica nanocapsules; they have a combined micro-and mesoporosity and a tuneable amount of both open and encapsulated mesopores and are much more stable than other tested micellar templated structures. Researchers of Mobil published in 1992 a breakthrough report on the synthesis of ordered mesoporous silica materials. All synthesised materials exhibit the typical X-Ray diffraction patterns of the 2D hexagonal pore ordering in the p6mm space group. 2 † The 77 K nitrogen isotherm in High resolution TEM measurements confirm this model. § The rather thick walls (~4 nm) of the large cylindrical mesopores are perforated with micropores. Moreover, the cylindrical mesopores themselves are 'plugged' with amorphous silica nanocapsules, which are also microporous. These nanocapsules are created by the large excess of the silica source (TEOS) that is used in the synthesis and by rapid hydrolysis of the silicon alkoxide at the very low pH used. The micropores in the silica walls can be explained by the penetration of hydrophilic poly(ethyleneoxide) chains of the triblock copolymer in the silica wall, as already suggested by Kruk et al. 7 The microporosity of the plugs may have a different origin. It is known that Pluronic triblock copolymers are in fact polydisperse mixtures of several triblock copolymers with a wide range of molecular weights, and that they contain appreciable amounts of diblock copolymers and even free PO chains. Some † Electronic supplementary information (ESI) available

A high proportion of red snapper sold in North Carolina is mislabeled

Seafood mislabeling occurs when a market label is inaccurate, primarily in terms of species identity, but also regarding weight, geographic origin, or other characteristics. This widespread problem allows cheaper or illegally-caught species to be marketed as species desirable to consumers. Previous studies have identified red snapper (Lutjanus campechanus) as one of the most frequently mislabeled seafood species in the United States. To quantify how common mislabeling of red snapper is across North Carolina, the Seafood Forensics class at the University of North Carolina at Chapel Hill used DNA barcoding to analyze samples sold as ‘‘red snapper’’ from restaurants, seafood markets, and grocery stores purchased in ten counties. Of 43 samples successfully sequenced and identified, 90.7% were mislabeled. Only one grocery store chain (of four chains tested) accurately labeled red snapper. The mislabeling rate for restaurants and seafood markets was 100%. Vermilion snapper (Rhomboplites aurorubens) and tilapia (Oreochromis aureus and O. niloticus) were the species most frequently substituted for red snapper (13 of 39 mislabeled samples for both taxa, or 26 of 39 mislabeled total). This study builds on previous mislabeling research by collecting samples of a specific species in a confined geographic region, allowing local vendors and policy makers to better understand the scope of red snapper mislabeling in North Carolina. This methodology is also a model for other academic institutions to engage undergraduate researchers in mislabeling data collection, sample processing, and analysis

Interactions between metal oxides and biomolecules: from fundamental understanding to applications

Metallo-oxide (MO) based bioinorganic nanocomposites promise unique structures, physico-chemical properties and novel bio-chemical functionalities and within the last decade, investment in research on materials such as ZnO, TiO2, SiO2 and GeO2 has significantly increased. Besides traditional approaches, the synthesis, shaping, structural patterning and post-processing chemical functionalization of the materials surface is inspired by strategies which mimic processes in nature. Would such materials deliver new technologies? Answering this question requires the merging of historical knowledge and current research from different fields of science. Practically, we need an effective defragmentation of the research area. From our perspective, the superficial accounting of material properties, chemistry of the surfaces and the behaviour of biomolecules next to such surfaces is a problem. This is particularly of concern when we wish to bridge between technologies in vitro and biotechnologies in vivo. Further, besides the potential practical technological efficiency and advantages such materials might exhibit, we have to consider the wider long-term implications of material stability and toxicity. In this contribution we present a critical review of recent advances in the chemistry and engineering of MO based biocomposites highlighting the role of interactions at the interface and the techniques by which these can be studied. At the end of the article we outline the challenges which hamper progress in research and extrapolate to developing and promising directions including additive manufacturing and synthetic biology that could benefit from molecular level understanding of interactions occurring between inanimate (abiotic) and living (biotic) materials