Manipulating the ABCs of self-assembly via low-χ block polymer design

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

Chang, Alice B.; Bates, Christopher M.; Lee, Byeongdu

Block polymer self-assembly typically translates molecular chain connectivity into mesoscale structure by exploiting incompatible blocks with large interaction parameters (χ ij). In this report, we demonstrate that the converse approach, encoding low-χ interactions in ABC bottlebrush triblock terpolymers (χ AC ≲ 0), promotes organization into a unique mixed-domain lamellar morphology which we designate LAM P. Transmission electron microscopy indicates that LAMP exhibits ACBC domain connectivity, in contrast to conventional three-domain lamellae (LAM 3) with ABCB periods. Complementary small angle X-ray scattering experiments reveal a strongly decreasing domain spacing with increasing total molar mass. Self-consistent field theory reinforces these observations andmore » predicts that LAM P is thermodynamically stable below a critical χ AC, above which LAM 3 emerges. Both experiments and theory expose close analogies to ABA triblock copolymer phase behavior, collectively suggesting that low-χ interactions between chemically similar or distinct blocks intimately influence self-assembly. Furthermore, these conclusions provide new opportunities in block polymer design with potential consequences spanning all self-assembling soft materials.« less

Manipulating the ABCs of self-assembly via low-χ block polymer design

DOE PAGES

Chang, Alice B.; Bates, Christopher M.; Lee, Byeongdu; ...

2017-06-06

Block polymer self-assembly typically translates molecular chain connectivity into mesoscale structure by exploiting incompatible blocks with large interaction parameters (χ ij). In this report, we demonstrate that the converse approach, encoding low-χ interactions in ABC bottlebrush triblock terpolymers (χ AC ≲ 0), promotes organization into a unique mixed-domain lamellar morphology which we designate LAM P. Transmission electron microscopy indicates that LAMP exhibits ACBC domain connectivity, in contrast to conventional three-domain lamellae (LAM 3) with ABCB periods. Complementary small angle X-ray scattering experiments reveal a strongly decreasing domain spacing with increasing total molar mass. Self-consistent field theory reinforces these observations andmore » predicts that LAM P is thermodynamically stable below a critical χ AC, above which LAM 3 emerges. Both experiments and theory expose close analogies to ABA triblock copolymer phase behavior, collectively suggesting that low-χ interactions between chemically similar or distinct blocks intimately influence self-assembly. Furthermore, these conclusions provide new opportunities in block polymer design with potential consequences spanning all self-assembling soft materials.« less

The blocking reagent optimization for the magnetoelastic biosensor

NASA Astrophysics Data System (ADS)

Hu, Jiajia; Chai, Yating; Horikawa, Shin; Wikle, Howard C.; Wang, Feng'en; Du, Songtao; Chin, Bryan A.; Hu, Jing

2015-06-01

The wireless phage-based magnetoelastic (ME) biosensor has proven to be promising for real-time detection of pathogenic bacteria on fresh produces. The ME biosensor consists of a freestanding ME resonator as the signal transducer and filamentous phage as the biomolecular-recognition element, which can specifically bind to a pathogen of interest. Due to the Joule magnetostriction effect, the biosensors can be placed into mechanical resonance when subjected to a time-varying magnetic field alternating at the sensor's resonant frequency. Upon the attachment of the target pathogen, the mass of the biosensor increases, thereby decreasing its resonant frequency. This paper presents an investigation of blocking reagents immobilization for detecting Salmonella Typhimurium on fresh food surfaces. Three different blocking reagents (BSA, SuperBlock blocking buffer, and blocker BLOTTO) were used and compared. The optical microscope was used for bacterial cells binding observation. Student t-test was used to statistically analysis the experiment results. The results shows that SuperBlock blocking buffer and blocker BLOTTO have much better blocking performance than usually used BSA.

Implications of grain size variation in magnetic field alignment of block copolymer blends

DOE PAGES

Rokhlenko, Yekaterina; Majewski, Pawel W.; Larson, Steven R.; ...

2017-03-28

Recent experiments have highlighted the intrinsic magnetic anisotropy in coil–coil diblock copolymers, specifically in poly(styrene- block-4-vinylpyridine) (PS- b-P4VP), that enables magnetic field alignment at field strengths of a few tesla. We consider here the alignment response of two low molecular weight (MW) lamallae-forming PS- b-P4VP systems. Cooling across the disorder–order transition temperature (T odt) results in strong alignment for the higher MW sample (5.5K), whereas little alignment is discernible for the lower MW system (3.6K). This disparity under otherwise identical conditions of field strength and cooling rate suggests that different average grain sizes are produced during slow cooling of thesemore » materials, with larger grains formed in the higher MW material. Blending the block copolymers results in homogeneous samples which display T odt, d-spacings, and grain sizes that are intermediate between the two neat diblocks. Similarly, the alignment quality displays a smooth variation with the concentration of the higher MW diblock in the blends, and the size of grains likewise interpolates between limits set by the neat diblocks, with a factor of 3.5× difference in the grain size observed in high vs low MW neat diblocks. Finally, these results highlight the importance of grain growth kinetics in dictating the field response in block copolymers and suggests an unconventional route for the manipulation of such kinetics.« less

Implications of grain size variation in magnetic field alignment of block copolymer blends

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

Rokhlenko, Yekaterina; Majewski, Pawel W.; Larson, Steven R.

Recent experiments have highlighted the intrinsic magnetic anisotropy in coil–coil diblock copolymers, specifically in poly(styrene- block-4-vinylpyridine) (PS- b-P4VP), that enables magnetic field alignment at field strengths of a few tesla. We consider here the alignment response of two low molecular weight (MW) lamallae-forming PS- b-P4VP systems. Cooling across the disorder–order transition temperature (T odt) results in strong alignment for the higher MW sample (5.5K), whereas little alignment is discernible for the lower MW system (3.6K). This disparity under otherwise identical conditions of field strength and cooling rate suggests that different average grain sizes are produced during slow cooling of thesemore » materials, with larger grains formed in the higher MW material. Blending the block copolymers results in homogeneous samples which display T odt, d-spacings, and grain sizes that are intermediate between the two neat diblocks. Similarly, the alignment quality displays a smooth variation with the concentration of the higher MW diblock in the blends, and the size of grains likewise interpolates between limits set by the neat diblocks, with a factor of 3.5× difference in the grain size observed in high vs low MW neat diblocks. Finally, these results highlight the importance of grain growth kinetics in dictating the field response in block copolymers and suggests an unconventional route for the manipulation of such kinetics.« less

Understanding self-assembly of charged-neutral block copolymer (BCP) and surfactant complexes using molecular dynamics (MD) simulation

NASA Astrophysics Data System (ADS)

Goswami, Monojoy; Sumpter, Bobby; Kilbey, Michael

Here we report the formation of phase separated BCP-surfactant complexes resulting from the electrostatic self-assembly of charge-neutral block copolymers with oppositely charged surfactants. Complexation behaviors of oppositely charged polyelectrolytes has gained considerable attention in the field of soft condensed matter physics due to their potential application as functional nanomaterials for batteries, wastewater treatment and drug delivery systems. Numerous experiments have examined the self-assembled structures resulting from complexation of charge-neutral BCP and surfactants, however, there is a lack of comprehensive understanding at the fundamental level. To help bridge this gap, we use, MD simulations to study self-assembly and dynamics of the BCP-surfactant complex at the molecular level. Our results show an overcharging effect in BCPs with hydrophobic neutral blocks and a formation of core-shell colloidal structure. Hydrophilic neutral blocks, on the other hand, show stable, hairy colloidal structures with neutral blocks forming a loosely-bound, fuzzy outer layer. Our results qualitatively agree with previous SANS and SAXS experiments. This work was supported by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences, Materials Science and Engineering Division.

Experiences in teaching of modeling and simulation with emphasize on equation-based and acausal modeling techniques.

PubMed

Kulhánek, Tomáš; Ježek, Filip; Mateják, Marek; Šilar, Jan; Kofránek, Jří

2015-08-01

This work introduces experiences of teaching modeling and simulation for graduate students in the field of biomedical engineering. We emphasize the acausal and object-oriented modeling technique and we have moved from teaching block-oriented tool MATLAB Simulink to acausal and object oriented Modelica language, which can express the structure of the system rather than a process of computation. However, block-oriented approach is allowed in Modelica language too and students have tendency to express the process of computation. Usage of the exemplar acausal domains and approach allows students to understand the modeled problems much deeper. The causality of the computation is derived automatically by the simulation tool.

MICROBIAL POPULATION CHANGES DURING BIOREMEDIATION OF AN EXPERIMENTAL OIL SPILL

EPA Science Inventory

Three crude oil bioremediation techniques were applied in a randomized block field experiment simulating a coastal oil-spill. Four treatments (no oil control, oil alone, oil + nutrients, and oil + nutrients + an indigenous inoculum) were applied. In-situ microbial community str...

Assessment of Surrogate Fractured Rock Networks for Evidence of Complex Behavior

NASA Astrophysics Data System (ADS)

Wood, T. R.; McJunkin, T. R.; Podgorney, R. K.; Glass, R. J.; Starr, R. C.; Stoner, D. L.; Noah, K. S.; LaViolette, R. A.; Fairley, J.

2001-12-01

A complex system or complex process is -"one whose properties are not fully explained by an understanding of its component parts". Results from field experiments conducted at the Hell's Half-Acre field site (Arco, Idaho) suggest that the flow of water in an unsaturated, fractured medium exhibits characteristics of a complex process. A series of laboratory studies is underway with sufficient rigor to determine if complex behavior observed in the field is in fact a fundamental characteristic of water flow in unsaturated, fractured media. As an initial step, a series of four duplicate experiments has been performed using an array of bricks to simulate fractured, unsaturated media. The array consisted of 12 limestone blocks cut to uniform size (5cm x 7 cm x 30 cm) stacked on end 4 blocks wide and 3 blocks high with the interfaces between adjacent blocks representing 3 vertical fractures intersecting 2 horizontal fractures. Water was introduced at three point sources on the upper boundary of the model at the top of the vertical fractures. Water was applied under constant flux at a rate below the infiltration capacity of the system, thus maintaining unsaturated flow conditions. Water was collected from the lower boundary via fiberglass wicks at the bottom of each fracture. An automated system acquired and processed water inflow and outflow data and time-lapse photographic data during each of the 72-hour tests. From these experiments, we see that a few general statements can be made on the overall advance of the wetting front in the surrogate fracture networks. For instance, flow generally converged with depth to the center fracture in the bottom row of bricks. Another observation is that fracture intersections integrate the steady flow in overlying vertical fractures and allow or cause short duration high discharge pulses or "avalanches" of flow to quickly traverse the fracture network below. Smaller scale tests of single fracture and fracture intersections are underway to evaluate a wide array of unit processes that are believed to contribute to complex behavior. Examples of these smaller scale experiments include the role of fracture intersections in integrating a steady inflow to generate giant fluctuations in network discharge; the influence of microbe growth on flow; and the role of geochemistry in alterations of flow paths. Experiments are planned at the meso and field scale to document and understand the controls on self-organized behavior. Modeling is being conducted in parallel with the experiments to understand how simulations can be improved to capture the complexity of fluid flow in fractured rock vadose zones and to make better predictions of contaminant transport.

A field study of the geomorphic effects of sublimating CO2 blocks on dune slopes at Coral Pink Dunes, Utah.

NASA Astrophysics Data System (ADS)

Bourke, Mary; Nield, Jo; Diniega, Serina; Hansen, Candy; McElwaine, Jim

2016-04-01

The seasonal sublimation of CO2 ice is an active driver of present-day surface change on Mars. Diniega et al (2013) proposed that a discrete type of Martian gully, found on southern hemisphere dunes, were formed by the movement of CO2 seasonal ice blocks. These 'Linear Gullies' consist primarily of long (100 m - 2.5 km) grooves with near-uniform width (few-10 m wide), and typical depth of <2 m. They are near-linear throughout most of their length but sometimes contains zones of low-to-high sinuosity. They are commonly bounded by levées. The groove is generally prefaced by a small alcove that originates at the dune brink. We present the results of a set of field experiments that were undertaken at the Coral Pink sand dunes, Utah. These are sister experiments to those undertaken in Arizona (Bourke et al, 2016). The experiments were undertaken on an active barchan dune with a 16 m long lee slope (30.3°). Ambient air temperature was 30°C and relative humidity was 25%; sand surface temperatures were 26.5°C. A CO2 ice block (60x205x210 mm) was placed at the dune brink and with a gentle nudge it moved downslope. The dynamics of the block movement were recorded using a pair of high resolution video cameras. Geomorphological observations were noted and topographic change was quantified using a Leica P20 terrestrial laser scanner with a resolution of 0.8 mm at 10 m, and change detection limits less than 3 mm. The block run was repeated a total of 10 times and launched from the same location at the dune brink. The experiment ran for 45 minutes. The block size was reduced to (45 x 190 x 195 mm) by the end of the run series. The resultant geomorphology shows that the separate block runs occupied different tracks leading to a triangular plan form shape with a maximum width of 3.5 m. This is different from the findings in Arizona where a narrower track span was recorded (1.7m) (Bourke et al, 2016). Similar block dynamics were observed at both sites (as blocks moved straight, swiveled and bounced downslope). Distinctive pits with arcuate rims on their downslope edge were formed where blocks bounced on the surface. These pits are at an almost equidistant spacing. Despite a longer slope (16 m as opposed to 8m at Grand Falls), no depositional apron was formed. Levee development was less consistent compared to the Arizona site, but a pronounced unpaired-levee formed towards the base of the lee slope. These data show that sublimating blocks of CO2 ice leave signatures of transport paths and are capable of eroding and transporting sediment. Diniega,S. et al (2013) A new dry hypothesis for the formation of Martian linear gullies. Icarus. Vol. 225, 1, p. 526-537. Bourke, M.C. et al (2016) The geomorphic effect of sublimating CO2 blocks on dune lee slopes at Grand Falls, Arizona. LPSC

Fluvial entrainment of low density peat blocks (block carbon)

NASA Astrophysics Data System (ADS)

Warburton, Jeff

2014-05-01

In many fluvial environments low density materials are transported in significant quantities and these form an important part of the stream load and /or have a distinct impact on sedimentation in these environments. However, there are significant gaps in understanding of how these materials are entrained and transported by streams and rivers. Eroding upland peatland environments in particular, frequently have fluvial systems in which large eroded peat blocks, often exceeding 1 m in length; form an important component of the stream material flux. Transport of this material is significant in determining rates of erosion but also has important impacts in terms of damage to infrastructure and carbon loss. This paper describes a field experiment designed to establish for the first time the conditions under which large peat blocks (c. > 0.1 m b axis) are initially entrained from a rough gravel bed. The field site is Trout Beck, in the North Pennines, Northern England which is an upland wandering river channel with occasional lateral and mid channel bars. Mean low flow stage is typically 0.2 m but during flood can rapidly rise, in one to two hours, to over 1.5 m. To study peat block entrainment a bespoke data acquisition system consisting of two pressure transducers, four release triggers and time lapse camera was set up. The pressure transducers provided a record of local depth and the release triggers were embedded in peat blocks to record initial motion and arranged on the rough stream bed. The time lapse camera provided verification of timing of block entrainment (during daylight hours) and also provided information on the mechanism of initial movement. Peat blocks were cut from a local source and were equidimensional, ranging in size from 0.1 to 0.7 m. The derived entrainment function is related to a critical depth of entrainment. Results demonstrate that peat blocks are entrained when the local depth approximates the height of the peat block. Blocks frequently shift position prior to entrainment but once entrained are rapidly transported downstream. Because of the rough stream bed local depth, measured on the four sides of the block varies markedly and needs to be considered in developing an appropriate entrainment function and; is useful in explaining initial movement prior to entrainment. In some experiments a small accelerometer (HOBO Pendant G data logger) was used to investigate transport dynamics following entrainment. Further work will seek to improve the entrainment function by extending the size range of tests, developing a shear stress related function and investigating the importance of block shape (rounding) on entrainment.

Characterization of blocks impacts from acoustic emissions: insights from laboratory experiments

NASA Astrophysics Data System (ADS)

Farin, Maxime; Mangeney, Anne; de Rosny, Julien; Toussaint, Renaud; Shapiro, Nikolaï

2014-05-01

Rockfalls, debris flows and rock avalanches represent a major natural hazard for the population in mountainous, volcanic and coastal areas but their direct observation on the field is very dangerous. Recent studies showed that gravitational instabilities can be detected and characterized (volume, duration,...) thanks to the seismic signal they generate. In an avalanche, individual block bouncing and rolling on the ground are expected to generated signals of higher frequencies than the main flow spreading. The identification of the time/frequency signature of individual blocks in the recorded signal remains however difficult. Laboratory experiments were conducted to investigate the acoustic signature of diverse simple sources corresponding to grains falling over thin plates of plexiglas and glass and over rock blocks. The elastic energy emitted by a single bouncing bead into the support was first quantitatively estimated and compared to the potential energy of fall and to the potential energy change during the shock. We obtained simple scaling laws relating the impactor characteristics (size, height of fall, material,...) to the elastic energy and spectral content. Next, we consider the collapse of granular columns made of steel spherical beads onto hard substrates. Initially, these columns were held by a magnetic field allowing to suppress suddenly the cohesion between the beads, and thus to minimize friction effects that would arise from side walls. We varied systematically the column volume, the column aspect ratio (height over length) and the grain size. This is shown to affect the signal envelope and frequency content. In the experiments, accelerometers (1 Hz to 56 kHz) were used to record the signals in a wide frequency range. The experiments were also monitored optically using fast cameras. Eventually, we looked at what types of features in the signal are affected by individual impacts, rolling of beads or by the large scale geometry of the avalanche.

Characterization of blocks impacts from elastic waves: insights from laboratory experiments

NASA Astrophysics Data System (ADS)

Farin, M.; Mangeney, A.; Toussaint, R.; De Rosny, J.; Shapiro, N.

2013-12-01

Rockfalls, debris flows and rock avalanches constitute a major natural hazard for the population in mountainous, volcanic and coastal areas but their direct observation on the field is very dangerous. Recent studies showed that gravitational instabilities can be detected and characterized (volume, duration,...) thanks to the seismic signal they generate. In an avalanche, individual block bouncing and rolling on the ground are expected to generated signals of higher frequencies than the main flow spreading. The identification of the time/frequency signature of individual blocks in the recorded signal remains however difficult. Laboratory experiments were conducted to investigate the acoustic signature of diverse simple sources corresponding to grains falling over thin plates of plexiglas and rock blocks. The elastic energy emitted by a single bouncing steel bead into the support was first quantitatively estimated and compared to the potential energy of fall and to the potential energy change during the shock. Next, we consider the collapse of granular columns made of steel spherical beads onto hard substrates. Initially, these columns were held by a magnetic field allowing to suppress suddenly the cohesion between the beads, and thus to minimize friction effects that would arise from side walls. We varied systematically the column volume, the column aspect ratio (height over length) and the grain size. This is shown to affect the signal envelope and frequency content. In the experiments, two types of acoustic sensors were used to record the signals in a wide frequency range: accelerometers (1 Hz to 56 kHz) and piezoelectric sensors (100 kHz to 1 MHz). The experiments were also monitored optically using fast cameras. We developed a technique to use quantitatively both types of sensors to evaluate the elastic energy emitted by the sources. Eventually, we looked at what types of features in the signal are affected by individual shocks or by the large scale geometry of the avalanche.

A field study of wind over a simulated block building

NASA Technical Reports Server (NTRS)

Frost, W.; Shahabi, A. M.

1977-01-01

A full-scale field study of the wind over a simulated two-dimensional building is reported. The study develops an experiment to investigate the structure and magnitude of the wind fields. A description of the experimental arrangement, the type and expected accuracy of the data, and the range of the data are given. The data are expected to provide a fundamental understanding of mean wind and turbulence structure of the wind field around the bluff body. Preliminary analysis of the data demonstrates the reliability and completeness of the data in this regard.

Dispersion and alignment of nanorods in cylindrical block copolymer thin films.

PubMed

Rasin, Boris; Chao, Huikuan; Jiang, Guoqian; Wang, Dongliang; Riggleman, Robert A; Composto, Russell J

2016-02-21

Although significant progress has been made in controlling the dispersion of spherical nanoparticles in block copolymer thin films, our ability to disperse and control the assembly of anisotropic nanoparticles into well-defined structures is lacking in comparison. Here we use a combination of experiments and field theoretic simulations to examine the assembly of gold nanorods (AuNRs) in a block copolymer. Experimentally, poly(2-vinylpyridine)-grafted AuNRs (P2VP-AuNRs) are incorporated into poly(styrene)-b-poly(2-vinylpyridine) (PS-b-P2VP) thin films with a vertical cylinder morphology. At sufficiently low concentrations, the AuNRs disperse in the block copolymer thin film. For these dispersed AuNR systems, atomic force microscopy combined with sequential ultraviolet ozone etching indicates that the P2VP-AuNRs segregate to the base of the P2VP cylinders. Furthermore, top-down transmission electron microscopy imaging shows that the P2VP-AuNRs mainly lie parallel to the substrate. Our field theoretic simulations indicate that the NRs are strongly attracted to the cylinder base where they can relieve the local stretching of the minority block of the copolymer. These simulations also indicate conditions that will drive AuNRs to adopt a vertical orientation, namely by increasing nanorod length and/or reducing the wetting of the short block towards the substrate.

Transmission-blocking interventions eliminate malaria from laboratory populations

PubMed Central

Blagborough, A. M.; Churcher, T. S.; Upton, L. M.; Ghani, A. C.; Gething, P. W.; Sinden, R. E.

2013-01-01

Transmission-blocking interventions aim to reduce the prevalence of infection in endemic communities by targeting Plasmodium within the insect host. Although many studies have reported the successful reduction of infection in the mosquito vector, direct evidence that there is an onward reduction in infection in the vertebrate host is lacking. Here we report the first experiments using a population, transmission-based study of Plasmodium berghei in Anopheles stephensi to assess the impact of a transmission-blocking drug upon both insect and host populations over multiple transmission cycles. We demonstrate that the selected transmission-blocking intervention, which inhibits transmission from vertebrate to insect by only 32%, reduces the basic reproduction number of the parasite by 20%, and in our model system can eliminate Plasmodium from mosquito and mouse populations at low transmission intensities. These findings clearly demonstrate that use of transmission-blocking interventions alone can eliminate Plasmodium from a vertebrate population, and have significant implications for the future design and implementation of transmission-blocking interventions within the field. PMID:23652000

Objective and subjective measures indicate that orthographically similar words produce a blocking experience.

PubMed

Leynes, P Andrew; Brown, Jaime; Landau, Joshua D

2011-01-01

Memory blocks are a common experience characterised by inappropriate retrieval of information that impairs memory search processes. In five studies, memory blocks were induced via exposure to orthographically similar words (Smith & Tindell, 1997) while participants reported their subjective experiences to determine whether the memory block effect (MBE) paradigm produces a feeling of being blocked. Experiments 1 and 3 provided evidence that the MBE is associated with more blocked experiences. In Experiments 2 and 4 increased blocking experiences correlated with blocked fragments when the experimental manipulation was disguised, which demonstrates that ratings were not contaminated by demand characteristics. Experiment 5 demonstrated that blocking happens even when there is no study list. Collectively, the subjective retrieval ratings and the objective response data provide converging evidence that exposure to orthographically similar words induces a memory block characterised by an ineffective memory search that perseverates on interfering information.

Buildings vs. ballistics: Quantifying the vulnerability of buildings to volcanic ballistic impacts using field studies and pneumatic cannon experiments

NASA Astrophysics Data System (ADS)

Williams, G. T.; Kennedy, B. M.; Wilson, T. M.; Fitzgerald, R. H.; Tsunematsu, K.; Teissier, A.

2017-09-01

Recent casualties in volcanic eruptions due to trauma from blocks and bombs necessitate more rigorous, ballistic specific risk assessment. Quantitative assessments are limited by a lack of experimental and field data on the vulnerability of buildings to ballistic hazards. An improved, quantitative understanding of building vulnerability to ballistic impacts is required for informing appropriate life safety actions and other risk reduction strategies. We assessed ballistic impacts to buildings from eruptions at Usu Volcano and Mt. Ontake in Japan and compiled available impact data from eruptions elsewhere to identify common damage patterns from ballistic impacts to buildings. We additionally completed a series of cannon experiments which simulate ballistic block impacts to building claddings to investigate their performance over a range of ballistic projectile velocities, masses and energies. Our experiments provide new insights by quantifying (1) the hazard associated with post-impact shrapnel from building and rock fragments; (2) the effect of impact obliquity on damage; and (3) the additional impact resistance buildings possess when claddings are struck in areas directly supported by framing components. This was not well identified in previous work which may have underestimated building vulnerability to ballistic hazards. To improve assessment of building vulnerability to ballistics, we use our experimental and field data to develop quantitative vulnerability models known as fragility functions. Our fragility functions and field studies show that although unreinforced buildings are highly vulnerable to large ballistics (> 20 cm diameter), they can still provide shelter, preventing death during eruptions.

Microphase separation in thin films of lamellar forming polydisperse di-block copolymers

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

Kumar, Rajeev; Lokitz, Bradley S.; Sides, Scott W.

Despite the ubiquity of polydispersity in chain lengths of di-block copolymers, its effects on microphase separation in thin films have eluded a clear understanding. In this paper, we have studied effects of polydispersity on the microphase separation in thin films of lamellar forming di-block copolymers using self-consistent field theory (SCFT) and neutron reflectivity experiments. Di-block copolymers containing a polydisperse block of poly(glycidylmethacrylate) (PGMA) connected to a near-monodisperse block poly(2-vinyl-4,4-dimethyl-d 6 azlactone) (PVDMA-d 6) are considered in this work. Effects of chain length polydispersity, film thickness, substrate–monomer and monomer–monomer interactions on the microphase segregation are studied using SCFT. The theoretical studymore » reveals that in comparison to a film created with monodisperse di-block copolymers, an increase in polydispersity tends to decrease the number of lamellar strata that can be packed in a film of given thickness. This is a direct consequence of an increase in lamellar domain spacing with an increase in polydispersity index. Furthermore, it is shown that polydispersity induces conformational asymmetry and an increase in the polydispersity index leads to an increase in the effective Kuhn segment length of the polydisperse blocks. It is shown that the conformational asymmetry effects, which are entropic in origin and of increasing importance as film thickness decreases, drive the polydisperse blocks to the middle of the films despite favorable substrate interactions. These predictions are verified by results from neutron reflectivity experiments on thin films made from moderately polydisperse PGMA-PVDMA-d 6 di-block copolymer deposited on silicon substrates. In conclusion, results from SCFT are used to predict neutron reflectivity profiles, providing a facile and robust route to obtain useful physical insights into the structure of polydisperse diblock copolymers at interfaces.« less

Microphase separation in thin films of lamellar forming polydisperse di-block copolymers

DOE PAGES

Kumar, Rajeev; Lokitz, Bradley S.; Sides, Scott W.; ...

2015-02-03

Despite the ubiquity of polydispersity in chain lengths of di-block copolymers, its effects on microphase separation in thin films have eluded a clear understanding. In this paper, we have studied effects of polydispersity on the microphase separation in thin films of lamellar forming di-block copolymers using self-consistent field theory (SCFT) and neutron reflectivity experiments. Di-block copolymers containing a polydisperse block of poly(glycidylmethacrylate) (PGMA) connected to a near-monodisperse block poly(2-vinyl-4,4-dimethyl-d 6 azlactone) (PVDMA-d 6) are considered in this work. Effects of chain length polydispersity, film thickness, substrate–monomer and monomer–monomer interactions on the microphase segregation are studied using SCFT. The theoretical studymore » reveals that in comparison to a film created with monodisperse di-block copolymers, an increase in polydispersity tends to decrease the number of lamellar strata that can be packed in a film of given thickness. This is a direct consequence of an increase in lamellar domain spacing with an increase in polydispersity index. Furthermore, it is shown that polydispersity induces conformational asymmetry and an increase in the polydispersity index leads to an increase in the effective Kuhn segment length of the polydisperse blocks. It is shown that the conformational asymmetry effects, which are entropic in origin and of increasing importance as film thickness decreases, drive the polydisperse blocks to the middle of the films despite favorable substrate interactions. These predictions are verified by results from neutron reflectivity experiments on thin films made from moderately polydisperse PGMA-PVDMA-d 6 di-block copolymer deposited on silicon substrates. In conclusion, results from SCFT are used to predict neutron reflectivity profiles, providing a facile and robust route to obtain useful physical insights into the structure of polydisperse diblock copolymers at interfaces.« less

Microphase separation in thin films of lamellar forming polydisperse di-block copolymers

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

Kumar, Rajeev; Lokitz, Bradley S.; Sides, Scott W.

Despite the ubiquity of polydispersity in chain lengths of di-block copolymers, its effects on microphase separation in thin films have eluded a clear understanding. In this work, we have studied effects of polydispersity on the microphase separation in thin films of lamellar forming di-block copolymers using self-consistent field theory (SCFT) and neutron reflectivity experiments. Di-block copolymers containing a polydisperse block of poly(glycidylmethacrylate) (PGMA) connected to a near-monodisperse block poly(2-vinyl-4,4-dimethyl-d6 azlactone) (PVDMA-d6) are considered in this work. Effects of chain length polydispersity, film thickness, substrate-monomer and monomer-monomer interactions on the microphase segregation are studied using SCFT. The theoretical study reveals thatmore » in comparison to a film created with monodisperse di-block copolymers, an increase in polydispersity tends to decrease the number of lamellar strata that can be packed in a film of given thickness. This is a direct consequence of an increase in lamellar domain spacing with an increase in polydispersity index. Furthermore, it is shown that polydispersity induces conformational asymmetry and an increase in the polydispersity index leads to an increase in the effective Kuhn segment length of the polydisperse blocks. It is shown that the conformational asymmetry effects, which are entropic in origin and of increasing importance as film thickness decreases, drive the polydisperse blocks to the middle of the films despite favorable substrate interactions. These predictions are verified by results from neutron reflectivity experiments on thin films made from moderately polydisperse PGMA-PVDMA-d6 di-block copolymer deposited on silicon substrates. Finally, results from SCFT are used to predict neutron reflectivity profiles, providing a facile and robust route to obtain useful physical insights into the structure of polydisperse diblock copolymers at interfaces.« less

Nonfumigant Alternatives to Methyl Bromide for Production of Snapdragon (Antirrhinum majus)

USDA-ARS?s Scientific Manuscript database

Two field experiments were conducted in north Florida to examine effects of solarization and reduced-risk pesticides on weeds, nematodes, soil-borne diseases, and yield of snapdragon (Antirrhinum majus). Five treatments were replicated five times in a randomized complete block design: fumigation wit...

MONTE GENEROSO ROCKFALL FIELD TEST (SWITZERLAND): Real size experiment to constraint 2D and 3D rockfall simulations

NASA Astrophysics Data System (ADS)

Humair, F.; Matasci, B.; Carrea, D.; Pedrazzini, A.; Loye, A.; Pedrozzi, G.; Nicolet, P.; Jaboyedoff, M.

2012-04-01

In numerical rockfall simulation, the runout of rockfall is highly dependent of the restitution coefficients which are one of the key parameters to estimate the energy and simulate the rebounds of the blocks during their travel. Restitution coefficients values derived from literature may however not be adapted to every rockfall area as they do not integrate some of the influencing parameters as, among others, block shape rock size, soil cover… The aim is to illustrate how real size rockfall experiment can improve the reliability of computational trajectory simulations of rockfall propagation by calibrating these latter with experiment extracted results. Experimental rockfall tests were performed in the slopes of Monte Generoso area (lat 720850/ long 84830) which is located in the canton of Ticino in south Switzerland above a highway. The field site is a forested area with a thin soil cover on a bedrock characterized by massive carbonates. The elevation ranges between 894m and 322m above see level with a slope of 35 to 40° in the upper part, 60 to 89° in the medium part and 28 to 38° in the lower part. 22 blocks with different size and shape were manually released down, imparting little or no initial velocity. The failing blocks were coloured to make the impacts easier to recognize. The paths of the failing blocks are recorded using two high speed cameras and the impacts of the blocks were sampled using dGNSS. The rockfall trajectories were analysed based on the movies. As the movies have to be referenced in x and y direction, the distance between two known point in the terrain as well as the position of the cameras were measured prior to the blocks throws. Measurements of bounce height, angular and translational velocity (as well as energy) and restitution coefficients (normal kn and tangential kt) were attempt to be deduced from the movies. First, a-priori simulations are compared with the real size experiment throw. Then a-fortiori simulations taking into account the results of the experimental testing are performed and compared with the a-priori simulations. 3D simulations were performed using a software that takes into account the effect of the forest cover in the blocky trajectory (RockyFor 3D) and an other that neglects this aspect (Rotomap; geo&soft international). 2D simulation (RocFall; Rocscience) profiles were located in the blocks paths deduced from 3D simulations. The preliminary results show that: (1) high speed movies are promising and allow us to track the blocks using video software, (2) the a-priori simulations tend to overestimate the runout distance which is certainly due to an underestimation of the obstacles as well as the breaking of the failing rocks which is not taken into account in the models, (3) the trajectories deduced from both a-priori simulation and real size experiment highlights the major influence of the channelized slope morphology on rock paths as it tends to follow the flow direction. This indicates that the 2D simulation have to be performed along the line of flow direction.

Should Aid Reward Performance? Evidence from a Field Experiment on Health and Education in Indonesia. NBER Working Paper No. 17892

ERIC Educational Resources Information Center

Olken, Benjamin A.; Onishi, Junko; Wong, Susan

2012-01-01

This paper reports an experiment in over 3,000 Indonesian villages designed to test the role of performance incentives in improving the efficacy of aid programs. Villages in a randomly-chosen one-third of subdistricts received a block grant to improve 12 maternal and child health and education indicators, with the size of the subsequent year's…

Passive electrical monitoring and localization of fluid leakages from wells

NASA Astrophysics Data System (ADS)

Revil, A.; Mao, D.; Haas, A. K.; Karaoulis, M.; Frash, L.

2015-02-01

Electrokinetic phenomena are a class of cross-coupling phenomena involving the relative displacement between the pore water (together with the electrical diffuse layer) with respect to the solid phase of a porous material. We demonstrate that electrical fields of electrokinetic nature can be associated with fluid leakages from wells. These leakages can be remotely monitored and the resulting signals used to localize their causative source distribution both in the laboratory and in field conditions. The first laboratory experiment (Experiment #1) shows how these electrical fields can be recorded at the surface of a cement block during the leakage of a brine from a well. The measurements were performed with a research-grade medical electroencephalograph and were inverted using a genetic algorithm to localize the causative source of electrical current and therefore, localize the leak in the block. Two snapshots of electrical signals were used to show how the leak evolved over time. The second experiment (Experiment #2) was performed to see if we could localize a pulse water injection from a shallow well in field conditions in the case of a heterogeneous subsurface. We used the same equipment as in Experiment #1 and processed the data with a trend removal algorithm, picking the amplitude from 24 receiver channels just after the water injection. The amplitude of the electric signals changed from the background level indicating that a volume of water was indeed flowing inside the well into the surrounding soil and then along the well. We used a least-square inversion algorithm to invert a snapshot of the electrical potential data at the injection time to localize the source of the self-potential signals. The inversion results show positive potential anomalies in the vicinity of the well. For both experiments, forward numerical simulations of the problem using a finite element package were performed in order to assess the underlying physics of the causative source of the observed electrical potential anomalies and how they are related to the flow of the water phase.

Disinfection of Common Waterborne Pathogens

ERIC Educational Resources Information Center

Swim, Edward W.

2010-01-01

As part of an integrative learning experience at the end of a sophomore Calculus II course at the United States Military Academy, this project served as a multidisciplinary problem-solving exercise that explored the connections among mathematics, biology, and other fields of study. During a seven-lesson block of instruction, this module was…

Surfactant seed coating - a strategy to improve turfgrass establishment on water repellent soils

USDA-ARS?s Scientific Manuscript database

Turfgrass managers can experience poor seeding success when trying to establish golf course greens and sports fields on water repellent soils. Nonionic soil surfactant formulations based on ethylene oxide-propylene oxide (EO/PO) block copolymers are commonly used to treat water repellent soils. Rece...

Establishing turfgrass on water repellent soil with ethylene oxide-propylene oxide block copolymer surfactant seed coatings

USDA-ARS?s Scientific Manuscript database

Turfgrass managers can experience poor seeding success when trying to establish golf course greens and sports fields in water repellent soils. Nonionic soil surfactant formulations are commonly used to treat water repellent soils and subsequently increase water reserves for seed germination and plan...

Scalable algorithms for three-field mixed finite element coupled poromechanics

NASA Astrophysics Data System (ADS)

Castelletto, Nicola; White, Joshua A.; Ferronato, Massimiliano

2016-12-01

We introduce a class of block preconditioners for accelerating the iterative solution of coupled poromechanics equations based on a three-field formulation. The use of a displacement/velocity/pressure mixed finite-element method combined with a first order backward difference formula for the approximation of time derivatives produces a sequence of linear systems with a 3 × 3 unsymmetric and indefinite block matrix. The preconditioners are obtained by approximating the two-level Schur complement with the aid of physically-based arguments that can be also generalized in a purely algebraic approach. A theoretical and experimental analysis is presented that provides evidence of the robustness, efficiency and scalability of the proposed algorithm. The performance is also assessed for a real-world challenging consolidation experiment of a shallow formation.

Breakthrough of two pesticides into tile drain and shallow groundwater: comparison of tile drain reaction and soil profiles within a field scale irrigation experiment

NASA Astrophysics Data System (ADS)

Klaus, Julian; Zehe, Erwin; Elsner, Martin; Palm, Juliane; Schneider, Dorothee; Schröder, Boris; Steinbeiss, Sibylle; West, Stephanie

2010-05-01

Preferential flow in macropores is a key process which strongly affects infiltration and may cause rapid transport of pesticides into depths of 80 to 150 cm. At these depths they experience a much slower degradation, may leach into shallow groundwater or enter a tile-drain and are transported into surface water bodies. Therefore, preferential transport might be an environmental problem, if the topsoil is bypassed, which has been originally thought to act as a filter to protect the subsoil and shallow groundwater. To investigate the behaviour of two pesticides with different chemical characteristics and to compare their transport behaviour in soil and into the tile drain an irrigation experiment was performed on a 400 m² field site. The experimental plot is located in the Weiherbach valley, south-west Germany, which basic geology consists of Loess and Keuper layers, the soil at the test site is a gleyic Colluvisol. The distance of the irrigation site to the Weiherbach brook is approximately 12 m, the field is drained with a tile-drain in about 1.2 m depth and shows discharge over the entire year. Three hours before the irrigation started, the farmer applied a pesticide solution consisting of Isoproturon (80 g) and Flufenacet (20 g) (IPU and FLU) according to conventional agricultural practice on the field plot. The irrigation took place in three time blocks (80 min, 60 min, 80 min) with in total 33.6 mm of precipitation. During the first block 1600 g of Bromide were mixed in the irrigation water. The drainage outlet was instrumented with a pressure probe. About 50 water samples ware taken during the experimental day, and several samples more the days after the experiment. They were analysed for the pesticides, bromide and water isotopes. In the two days after the experiment three soil profiles were excavated and soil samples were taken on a 10x10 cm² scheme. One week after the experiment two additional profiles were excavated. The soil was analysed for IPU, FLU and bromide. The tile drain water showed traces of bromide and both pesticides within a few minutes. IPU showed highest concentration before the hydrograph started to increase, while bromide and FLU are strongly correlated to the hydrograph. Although IPU is less sorptive than FLU the concentrations and total transported mass of FLU were significantly higher then for IPU. The hydrograph reacted with two peaks on the three block irrigation; the two peaks can be attributed to the second and third irrigation block. Analysis of the water isotopes showed that during the experiment the event water mainly consisted of soil water. While the tile drain showed significant reaction in pesticides transport the picture deriving from soil profiles were different. Especially FLU was found mainly in the upper soil parts, so the bypassing might occurred so fast that it was only marginally absorbed in deeper soil party, but transported to the drain or shallow groundwater. As preferential flow paths earthworm burrows of different species could be identified, although the area density and species number of anecic earthworms was quite low compared to other field sites.

Effect of treated tannery effluent with domestic wastewater and amendments on growth and yield of cotton.

PubMed

Jagathjothi, N; Amanullah, M Mohamed; Muthukrishnan, P

2013-11-15

Pot culture and field experiments were carried out at the Common Effluent Treatment Plant (CETP), Dindigul during kharif 2011-12 to investigate the influence of irrigation of treated tannery effluent along with domestic wastewater on growth, yield attributes and yield of cotton. The pot culture was in a factorial completely randomized design and field experiment laid out in factorial randomized block design with four replications. The results revealed that the mixing proportion of 25% Treated Tannery Effluent (TTE)+75% domestic wastewater (DWW) application recorded taller plants, higher dry matter production, number of sympodial branches plant(-1), number of fruiting points plant(-1), number of bolls plant(-1) and seed cotton yield with yield reduction of 15.28 and 16.11% compared to normal water irrigation under pot culture and field experiment, respectively. Regarding amendments, gypsum application registered higher seed cotton yield followed by VAM.

Evaluation of fungicide rotations for management of Phytophthora fruit rot of watermelon, 2015

USDA-ARS?s Scientific Manuscript database

The experiment was conducted at the U.S. Vegetable Laboratory farm in Charleston, SC. The soil was Yonges loamy fine sand. For the past 6 years, the field has been infested with Phytophthora capsici. The experimental design was a randomized complete block with four replications. Five-week-old seedli...

Responses of rice cultivars and elite lines to diseases in conventional production system, 2010

USDA-ARS?s Scientific Manuscript database

The experiment was established in a field of League-type soil (3% sand, 32% silt, and 64% clay) under organic management for many years at the Texas A&M University System's Agrilife Research and Extension Center, Beaumont. Twenty rice cultivars and lines were arranged in a randomized complete block ...

Morpho-physiological characterization of cold-and pre-flowering drought tolerance in grain Sorghum (Sorghum bicolor L. Moench) inbreds

USDA-ARS?s Scientific Manuscript database

Aim: The relationships between early-season cold temperature germination and preflowering drought stress in eight grain sorghum inbreds were assessed using morphophysiological traits. Study Design: Field was laid out in a randomized complete block design. Place and Duration: The experiment was condu...

Interpreting Neutron Reflectivity Profiles of Diblock Copolymer Nanocomposite Thin Films Using Hybrid Particle-Field Simulations

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

Mahalik, Jyoti P.; Dugger, Jason W.; Sides, Scott W.

Mixtures of block copolymers and nanoparticles (block copolymer nanocomposites) are known to microphase separate into a plethora of microstructures, depending on the composition, length scale and nature of interactions among its different constituents. Theoretical and experimental works on this class of nanocomposites have already high-lighted intricate relations among chemical details of the polymers, nanoparticles, and various microstructures. Confining these nanocomposites in thin films yields an even larger array of structures, which are not normally observed in the bulk. In contrast to the bulk, exploring various microstructures in thin films by the experimental route remains a challenging task. Here in thismore » work, we construct a model for the thin films of lamellar forming diblock copolymers containing spherical nanoparticles based on a hybrid particle-field approach. The model is benchmarked by comparison with the depth profiles obtained from the neutron reflectivity experiments for symmetric poly(deuterated styrene-b-n butyl methacrylate) copolymers blended with spherical magnetite nanoparticles covered with hydrogenated poly(styrene) corona. We show that the model based on a hybrid particle-field approach provides details of the underlying microphase separation in the presence of the nanoparticles through a direct comparison to the neutron reflectivity data. This work benchmarks the application of the hybrid particle-field model to extract the interaction parameters for exploring different microstructures in thin films containing block copolymers and nanocomposites.« less

Interpreting Neutron Reflectivity Profiles of Diblock Copolymer Nanocomposite Thin Films Using Hybrid Particle-Field Simulations

DOE PAGES

Mahalik, Jyoti P.; Dugger, Jason W.; Sides, Scott W.; ...

2018-04-10

Mixtures of block copolymers and nanoparticles (block copolymer nanocomposites) are known to microphase separate into a plethora of microstructures, depending on the composition, length scale and nature of interactions among its different constituents. Theoretical and experimental works on this class of nanocomposites have already high-lighted intricate relations among chemical details of the polymers, nanoparticles, and various microstructures. Confining these nanocomposites in thin films yields an even larger array of structures, which are not normally observed in the bulk. In contrast to the bulk, exploring various microstructures in thin films by the experimental route remains a challenging task. Here in thismore » work, we construct a model for the thin films of lamellar forming diblock copolymers containing spherical nanoparticles based on a hybrid particle-field approach. The model is benchmarked by comparison with the depth profiles obtained from the neutron reflectivity experiments for symmetric poly(deuterated styrene-b-n butyl methacrylate) copolymers blended with spherical magnetite nanoparticles covered with hydrogenated poly(styrene) corona. We show that the model based on a hybrid particle-field approach provides details of the underlying microphase separation in the presence of the nanoparticles through a direct comparison to the neutron reflectivity data. This work benchmarks the application of the hybrid particle-field model to extract the interaction parameters for exploring different microstructures in thin films containing block copolymers and nanocomposites.« less

Orientational control of block copolymer microdomains by sub-tesla magnetic fields

NASA Astrophysics Data System (ADS)

Gopinadhan, Manesh; Choo, Youngwoo; Feng, Xunda; Kawabata, Kohsuke; di, Xiaojun; Osuji, Chinedum

Magnetic fields offer a versatile approach to controlling the orientation of block copolymer (BCP) microdomains during self-assembly. To date however, such control has required the imposition of large magnetic fields (>3T), necessitating the use of complex magnet systems - either superconducting or very large conventional resistive magnets. Here we demonstrate the ability to direct BCP self-assembly using considerably smaller fields (<1T) which are accessible using simple rare-earth permanent magnets. The low field alignment is enabled by the presence of small quantities of mesogenic species that are blended into, and co-assemble with the liquid crystalline (LC) mesophase of the side-chain LC BCP under study. In situ SAXS experiments reveal a pronounced dependence of the critical alignment field strength on the stoichiometry of the blend, and the ability to generate aligned microdomains with orientational distribution coefficients exceeding 0.95 at sub-1 T fields for appropriate stoichiometries. The alignment response overall can be rationalized in terms of increased mobility and grain size due to the presence of the mesogenic additive. We use a permanent magnet to fabricate films with aligned nanopores, and the utility of this approach to generate complex BCP microdomain patterns in thin films by local field screening are highlighted. NSF DMR-1410568 and DMR-0847534.

Total x-ray power measurements in the Sandia LIGA program.

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

Malinowski, Michael E.; Ting, Aili

2005-08-01

Total X-ray power measurements using aluminum block calorimetry and other techniques were made at LIGA X-ray scanner synchrotron beamlines located at both the Advanced Light Source (ALS) and the Advanced Photon Source (APS). This block calorimetry work was initially performed on the LIGA beamline 3.3.1 of the ALS to provide experimental checks of predictions of the LEX-D (LIGA Exposure- Development) code for LIGA X-ray exposures, version 7.56, the version of the code in use at the time calorimetry was done. These experiments showed that it was necessary to use bend magnet field strengths and electron storage ring energies different frommore » the default values originally in the code in order to obtain good agreement between experiment and theory. The results indicated that agreement between LEX-D predictions and experiment could be as good as 5% only if (1) more accurate values of the ring energies, (2) local values of the magnet field at the beamline source point, and (3) the NIST database for X-ray/materials interactions were used as code inputs. These local magnetic field value and accurate ring energies, together with NIST database, are now defaults in the newest release of LEX-D, version 7.61. Three dimensional simulations of the temperature distributions in the aluminum calorimeter block for a typical ALS power measurement were made with the ABAQUS code and found to be in good agreement with the experimental temperature data. As an application of the block calorimetry technique, the X-ray power exiting the mirror in place at a LIGA scanner located at the APS beamline 10 BM was measured with a calorimeter similar to the one used at the ALS. The overall results at the APS demonstrated the utility of calorimetry in helping to characterize the total X-ray power in LIGA beamlines. In addition to the block calorimetry work at the ALS and APS, a preliminary comparison of the use of heat flux sensors, photodiodes and modified beam calorimeters as total X-ray power monitors was made at the ALS, beamline 3.3.1. This work showed that a modification of a commercially available, heat flux sensor could result in a simple, direct reading beam power meter that could be a useful for monitoring total X-ray power in Sandia's LIGA exposure stations at the ALS, APS and Stanford Synchrotron Radiation Laboratory (SSRL).« less

Magnetic Field Alignment of PS-P4VP: a Non-Liquid Crystalline Coil-Coil Block Copolymer

NASA Astrophysics Data System (ADS)

Rokhlenko, Yekaterina; Zhang, Kai; Larson, Steven; Gopalan, Padma; O'Hern, Corey; Osuji, Chinedum

2015-03-01

Magnetic fields provide the ability to control alignment of self-assembled soft materials such as block copolymers. Most prior work in this area has relied on the presence of ordered assemblies of anisotropic liquid crystalline species to ensure sufficient magnetic anisotropy to drive alignment. Recent experiments with poly(styrene-b-4-vinylpyridine), a non-liquid crystalline BCP, however, show field-induced alignment of a lamellar microstructure during cooling across the order-disorder transition. Using in situ x-ray scattering, we examine the roles of field strength and cooling rate on the alignment response of this low MW coil-coil BCP. Alignment is first observed at field strengths as low as 1 Tesla and improves markedly with both increasing field strength and slower cooling. We present a geometric argument to illustrate the origin of a finite, non-trivial magnetic susceptibility anisotropy for highly stretched surface-tethered polymer chains and corroborate this using coarse-grained molecular dynamics simulations. We rationalize the magnetic field response of the system in terms of the mobility afforded by the absence of entanglements, the intrinsic anisotropy resulting from the stretched polymer chains and sterically constrained conjugated rings, and the large grain size in these low molecular weight materials.

Prescribed fire effects on erosion parameters in a perennial grassland

Treesearch

Mary E. O' Dea; D. Phillip Guertin

2003-01-01

A 2-year field experiment was undertaken to quantify theinteracting effects of a late-spring prescribed burn and summerrainfall on seasonal runoff and erosion in a southern Arizonagrassland. Six blocks with walled subplots (n = 24) were installedon a hillslope to measure changes to plant, soil, and hydrologicvariables in response to treatments. Increased bulk density,...

Evaluation of fungicide rotations and MELCAST for management of Phytophthora fruit rot of watermelon, 2014

USDA-ARS?s Scientific Manuscript database

The experiment was conducted at the U.S. Vegetable Laboratory farm in Charleston, SC. The soil was Yonges loamy fine sand, and for the past 5 years, the field has been infested with Phytophthora capsici. The experimental design was a randomized complete block with four replications. Four-week-old...

Responses of rice cultivars and elite lines to diseases in tilled organic production system, 2010

USDA-ARS?s Scientific Manuscript database

The experiment was established in a field of League-type soil (3% sand, 32% silt, and 64% clay) under organic management for many years at the Texas A&M University system’' Agrilife Research and Extension Center, Beaumont. Twenty rice cultivars and lines were arranged in a randomized complete block ...

Responses of rice cultivars and elite lines to diseases in no-till organic production system, 2010

USDA-ARS?s Scientific Manuscript database

The experiment was established in a field of League-type soil (3% sand, 32% silt, and 64% clay) under organic management for many years at the Texas A&M University System's Agrilife Research and Extension Center, Beaumont. Twenty rice cultivars and lines were arranged in a randomized complete block ...

East Cameron Block 270, a Pleistocene field

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

Holland, D.S.; Sutley, C.E.; Berlitz, R.E.

1974-01-01

Exploration of the Plio-Pleistocene in the Gulf of Mexico since 1970 has discovered significant hydrocarbon reserves. One of the better gas fields to date has been the Block 270 E. Cameron field. Utilization of a coordinated exploitation plan with Schlumberger has allowed Pennzoil as operator, to develop and put on production the Block 270 field in a minimum time period. Block 270 field is a N.-S. trending faulted nose at 6,000 ft. At G-Sand depth (8,700 ft), the structure has closed, forming an elongated N.-S. structure with dip in all directions from the Block 270 area. Closure is the resultmore » of contemporaneous growth on the E. bounding regional fault. Structural and stratigraphic interpretations from dipmeters were used to help determine the most favorable offset locations.« less

Revisiting the blocking force test on ferroelectric ceramics using high energy x-ray diffraction

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

Daniel, L., E-mail: laurent.daniel@u-psud.fr; GeePs; Hall, D. A.

2015-05-07

The blocking force test is a standard test to characterise the properties of piezoelectric actuators. The aim of this study is to understand the various contributions to the macroscopic behaviour observed during this experiment that involves the intrinsic piezoelectric effect, ferroelectric domain switching, and internal stress development. For this purpose, a high energy diffraction experiment is performed in-situ during a blocking force test on a tetragonal lead zirconate titanate (PZT) ceramic (Pb{sub 0.98}Ba{sub 0.01}(Zr{sub 0.51}Ti{sub 0.49}){sub 0.98}Nb{sub 0.02}O{sub 3}). It is shown that the usual macroscopic linear interpretation of the test can also be performed at the single crystal scale,more » allowing the identification of local apparent piezoelectric and elastic properties. It is also shown that despite this apparent linearity, the blocking force test involves significant non-linear behaviour mostly due to domain switching under electric field and stress. Although affecting a limited volume fraction of the material, domain switching is responsible for a large part of the macroscopic strain and explains the high level of inter- and intra-granular stresses observed during the course of the experiment. The study shows that if apparent piezoelectric and elastic properties can be identified for PZT single crystals from blocking stress curves, they may be very different from the actual properties of polycrystalline materials due to the multiplicity of the physical mechanisms involved. These apparent properties can be used for macroscopic modelling purposes but should be considered with caution if a local analysis is aimed at.« less

Formation and Characterization of Anisotropic Block Copolymer Gels

NASA Astrophysics Data System (ADS)

Liaw, Chya Yan; Joester, Derk; Burghardt, Wesley; Shull, Kenneth

2012-02-01

Cylindrical micelles formed from block copolymer solutions closely mimic biological fibers that are presumed to guide mineral formation during biosynthesis of hard tissues like bone. The goal of our work is to use acrylic block copolymers as oriented templates for studying mineral formation reactions in model systems where the structure of the underlying template is well characterized and reproducible. Self-consistent mean field theory is first applied to investigate the thermodynamically stable micellar morphologies as a function of temperature and block copolymer composition. Small-angle x-ray scattering, optical birefringence and shear rheometry are used to study the morphology development during thermal processing. Initial experiments are based on a thermally-reversible alcohol-soluble system that can be converted to an aqueous gel by hydrolysis of a poly(t-butyl methacrylate) block to a poly(methacrylic acid) block. Aligned cylindrical domains are formed in the alcohol-based system when shear is applied in an appropriate temperature regime, which is below the critical micelle temperature but above the temperature at which the relaxation time of the gels becomes too large. Processing strategies for producing the desired cylindrical morphologies are being developed that account for both thermodynamic and kinetic effects.

On spatial attention and its field size on the repulsion effect

PubMed Central

Cutrone, Elizabeth K.; Heeger, David J.; Carrasco, Marisa

2018-01-01

We investigated the attentional repulsion effect—stimuli appear displaced further away from attended locations—in three experiments: one with exogenous (involuntary) attention, and two with endogenous (voluntary) attention with different attention-field sizes. It has been proposed that differences in attention-field size can account for qualitative differences in neural responses elicited by attended stimuli. We used psychophysical comparative judgments and manipulated either exogenous attention via peripheral cues or endogenous attention via central cues and a demanding rapid serial visual presentation task. We manipulated the attention field size of endogenous attention by presenting streams of letters at two specific locations or at two of many possible locations during each block. We found a robust attentional repulsion effect in all three experiments: with endogenous and exogenous attention and with both attention-field sizes. These findings advance our understanding of the influence of spatial attention on the perception of visual space and help relate this repulsion effect to possible neurophysiological correlates.

How to recognize a “Beast Quake” and a “Dance Quake”

USGS Publications Warehouse

Malone, Stephen; Hall, Kelley; Simmons, Lynn; Vidale, John

2015-01-01

Any good seismologist–carryball (i.e., American football) fan remembers the “beast quake” of 2011. Seahawks fans’ exuberant reactions to a Marshawn Lynch (in beast mode) run caused the stadium to shake enough to be well recorded on a strong‐motion seismograph a block away (Vidale, 2011). With the Seahawks at home for the National Football Conference (NFC) Championship playoffs, both last year and this year, the Pacific Northwest Seismic Network (PNSN) received permission to install some seismometers in the stadium. Motivations for the experiment included testing the field and telemetry equipment, examining analysis and display techniques, and practicing quick reactions to mobilize field experiments. With PNSN students and staff who are also Seahawks fans, it was not hard to get volunteers to do the installations and monitor the on‐field actions and the resulting seismograms.

An adaptive block-based fusion method with LUE-SSIM for multi-focus images

NASA Astrophysics Data System (ADS)

Zheng, Jianing; Guo, Yongcai; Huang, Yukun

2016-09-01

Because of the lenses' limited depth of field, digital cameras are incapable of acquiring an all-in-focus image of objects at varying distances in a scene. Multi-focus image fusion technique can effectively solve this problem. Aiming at the block-based multi-focus image fusion methods, the problem that blocking-artifacts often occurs. An Adaptive block-based fusion method based on lifting undistorted-edge structural similarity (LUE-SSIM) is put forward. In this method, image quality metrics LUE-SSIM is firstly proposed, which utilizes the characteristics of human visual system (HVS) and structural similarity (SSIM) to make the metrics consistent with the human visual perception. Particle swarm optimization(PSO) algorithm which selects LUE-SSIM as the object function is used for optimizing the block size to construct the fused image. Experimental results on LIVE image database shows that LUE-SSIM outperform SSIM on Gaussian defocus blur images quality assessment. Besides, multi-focus image fusion experiment is carried out to verify our proposed image fusion method in terms of visual and quantitative evaluation. The results show that the proposed method performs better than some other block-based methods, especially in reducing the blocking-artifact of the fused image. And our method can effectively preserve the undistorted-edge details in focus region of the source images.

Experimental investigation and CFD analysis on cross flow in the core of PMR200

DOE PAGES

Lee, Jeong -Hun; Yoon, Su -Jong; Cho, Hyoung -Kyu; ...

2015-04-16

The Prismatic Modular Reactor (PMR) is one of the major Very High Temperature Reactor (VHTR) concepts, which consists of hexagonal prismatic fuel blocks and reflector blocks made of nuclear gradegraphite. However, the shape of the graphite blocks could be easily changed by neutron damage duringthe reactor operation and the shape change can create gaps between the blocks inducing the bypass flow.In the VHTR core, two types of gaps, a vertical gap and a horizontal gap which are called bypass gap and cross gap, respectively, can be formed. The cross gap complicates the flow field in the reactor core by connectingmore » the coolant channel to the bypass gap and it could lead to a loss of effective coolant flow in the fuel blocks. Thus, a cross flow experimental facility was constructed to investigate the cross flow phenomena in the core of the VHTR and a series of experiments were carried out under varying flow rates and gap sizes. The results of the experiments were compared with CFD (Computational Fluid Dynamics) analysis results in order to verify its prediction capability for the cross flow phenomena. Fairly good agreement was seen between experimental results and CFD predictions and the local characteristics of the cross flow was discussed in detail. Based on the calculation results, pressure loss coefficient across the cross gap was evaluated, which is necessary for the thermo-fluid analysis of the VHTR core using a lumped parameter code.« less

Field-scale experiments reveal persistent yield gaps in low-input and organic cropping systems

PubMed Central

Kravchenko, Alexandra N.; Snapp, Sieglinde S.; Robertson, G. Philip

2017-01-01

Knowledge of production-system performance is largely based on observations at the experimental plot scale. Although yield gaps between plot-scale and field-scale research are widely acknowledged, their extent and persistence have not been experimentally examined in a systematic manner. At a site in southwest Michigan, we conducted a 6-y experiment to test the accuracy with which plot-scale crop-yield results can inform field-scale conclusions. We compared conventional versus alternative, that is, reduced-input and biologically based–organic, management practices for a corn–soybean–wheat rotation in a randomized complete block-design experiment, using 27 commercial-size agricultural fields. Nearby plot-scale experiments (0.02-ha to 1.0-ha plots) provided a comparison of plot versus field performance. We found that plot-scale yields well matched field-scale yields for conventional management but not for alternative systems. For all three crops, at the plot scale, reduced-input and conventional managements produced similar yields; at the field scale, reduced-input yields were lower than conventional. For soybeans at the plot scale, biological and conventional managements produced similar yields; at the field scale, biological yielded less than conventional. For corn, biological management produced lower yields than conventional in both plot- and field-scale experiments. Wheat yields appeared to be less affected by the experimental scale than corn and soybean. Conventional management was more resilient to field-scale challenges than alternative practices, which were more dependent on timely management interventions; in particular, mechanical weed control. Results underscore the need for much wider adoption of field-scale experimentation when assessing new technologies and production-system performance, especially as related to closing yield gaps in organic farming and in low-resourced systems typical of much of the developing world. PMID:28096409

Field-scale experiments reveal persistent yield gaps in low-input and organic cropping systems.

PubMed

Kravchenko, Alexandra N; Snapp, Sieglinde S; Robertson, G Philip

2017-01-31

Knowledge of production-system performance is largely based on observations at the experimental plot scale. Although yield gaps between plot-scale and field-scale research are widely acknowledged, their extent and persistence have not been experimentally examined in a systematic manner. At a site in southwest Michigan, we conducted a 6-y experiment to test the accuracy with which plot-scale crop-yield results can inform field-scale conclusions. We compared conventional versus alternative, that is, reduced-input and biologically based-organic, management practices for a corn-soybean-wheat rotation in a randomized complete block-design experiment, using 27 commercial-size agricultural fields. Nearby plot-scale experiments (0.02-ha to 1.0-ha plots) provided a comparison of plot versus field performance. We found that plot-scale yields well matched field-scale yields for conventional management but not for alternative systems. For all three crops, at the plot scale, reduced-input and conventional managements produced similar yields; at the field scale, reduced-input yields were lower than conventional. For soybeans at the plot scale, biological and conventional managements produced similar yields; at the field scale, biological yielded less than conventional. For corn, biological management produced lower yields than conventional in both plot- and field-scale experiments. Wheat yields appeared to be less affected by the experimental scale than corn and soybean. Conventional management was more resilient to field-scale challenges than alternative practices, which were more dependent on timely management interventions; in particular, mechanical weed control. Results underscore the need for much wider adoption of field-scale experimentation when assessing new technologies and production-system performance, especially as related to closing yield gaps in organic farming and in low-resourced systems typical of much of the developing world.

Artificial intelligence analysis of hyperspectral remote sensing data for management of water, weed, and nitrogen stresses in corn fields

NASA Astrophysics Data System (ADS)

Waheed, Tahir

This study investigated the possibility of using ground-based remotely sensed hyperspectral observations with a special emphasis on detection of water, weed and nitrogen stresses contributing towards in-season decision support for precision crop management (PCM). A three factor split-split-plot experiment, with four randomized blocks as replicates, was established during the growing seasons of 2003 and 2004. Corn (Zea mays L.) hybrid DKC42-22 was grown because this hybrid is a good performer on light soils in Quebec. There were twelve 12 x 12m plots in a block (one replication per treatment per block) and the total number of plots was 48. Water stress was the main factor in the experiment. A drip irrigation system was laid out and each block was split into irrigated and non-irrigated halves. The second main factor of the experiment was weeds with two levels i.e. full weed control and no weed control. Weed treatments were assigned randomly by further splitting the irrigated and non-irrigated sub-blocks into two halves. Each of the weed treatments was furthermore split into three equal sub-sub-plots for nitrogen treatments (third factor of the experiment). Nitrogen was applied at three levels i.e. 50, 150 and 250 kg N ha-1 (Quebec norm is between 120-160 kg N ha-1). The hyperspectral data were recorded (spectral resolution = 1 nm) mid-day (between 1000 and 1400 hours) with a FieldSpec FR spectroradiometer over a spectral range of 400-2500 run at three growth stages namely: early growth, tasseling and full maturity, in each of the growing season. There are two major original contributions in this thesis: First is the development of a hyperspectral data analysis procedure for separating visible (400-700 nm), near-infrared (700-1300 nm) and mid-infrared (1300-2500 nm) regions of the spectrum for use in discriminant analysis procedure. In addition, of all the spectral band-widths analyzed, seven waveband-aggregates were identified using STEPDISC procedure, which were the most effective for classifying combined water, weed, and nitrogen stress. The second contribution is the successful classification of hyperspectral observations acquired over an agricultural field, using three innovative artificial intelligence approaches; support vector machines (SVM), genetic algorithms (GA) and decision tree (DT) algorithms. These AI approaches were used to evaluate a combined effect of water, weed and nitrogen stresses in corn and of all the three AI approaches used, SVM produced the best results (overall accuracy ranging from 88% to 100%). The general conclusion is that the conventional statistical and artificial intelligence techniques used in this study are all useful for quickly mapping combined affects of irrigation, weed and nitrogen stresses (with overall accuracies ranging from 76% to 100%). These approaches have strong potential and are of great benefit to those investigating the in-season impact of irrigation, weed and nitrogen management for corn crop production and other environment related challenges.

From spinning conformal blocks to matrix Calogero-Sutherland models

NASA Astrophysics Data System (ADS)

Schomerus, Volker; Sobko, Evgeny

2018-04-01

In this paper we develop further the relation between conformal four-point blocks involving external spinning fields and Calogero-Sutherland quantum mechanics with matrix-valued potentials. To this end, the analysis of [1] is extended to arbitrary dimensions and to the case of boundary two-point functions. In particular, we construct the potential for any set of external tensor fields. Some of the resulting Schrödinger equations are mapped explicitly to the known Casimir equations for 4-dimensional seed conformal blocks. Our approach furnishes solutions of Casimir equations for external fields of arbitrary spin and dimension in terms of functions on the conformal group. This allows us to reinterpret standard operations on conformal blocks in terms of group-theoretic objects. In particular, we shall discuss the relation between the construction of spinning blocks in any dimension through differential operators acting on seed blocks and the action of left/right invariant vector fields on the conformal group.

Superconducting magnet and fabrication method

NASA Technical Reports Server (NTRS)

Israelsson, Ulf E. (Inventor); Strayer, Donald M. (Inventor)

1994-01-01

A method of trapping a field in a block of superconductor material, includes providing (i) a block of material defining a bore, (ii) a high permeability core within the bore that defines a low reluctance path through the bore, (iii) a high permeability external structure on the exterior of the block of material that defines a low reluctance path between opposite ends of the core, and (iv) an electromagnet configured to apply a magnetic field around the high permeability core. The method proceeds by energizing the electromagnet to produce an applied magnetic field around the high permeability core, cooling the block of material sufficiently to render the block of material superconducting, de-energizing the electromagnet to result in a trapped magnetic field, and at least partially removing the low reluctance path defined by the core and the external structure in order to increase the magnetic flux density of the trapped magnetic field.

Order and Disorder in Short Block Polymers

NASA Astrophysics Data System (ADS)

Bates, Frank S.

2015-03-01

Block polymers have captivated the interest of scientists and engineers for more than half a century. The phase behavior of this class of self-assembling soft material is well understood in the limit of infinite molecular weight, based on the self-consistent mean-field theory pioneered by Leibler. At practical molecular sizes, typically around N ~ 1000 repeat units, fluctuation effects become highly significant in the vicinity of the order disorder transition. One-loop corrections to mean-field theory, first described by Brazovski and applied to block polymers by Fredrickson and Helfand, are not expected to be applicable in this limit. Moreover, the drive towards ever smaller domain dimensions, and the opportunity to circumvent transport limitations associated with entanglements, have motivated experiments with yet lower molecular weight block polymers, N less than 100. This presentation will describe the consequences of fluctuations and the equilibrium structural properties of short model AB diblock polymers in the symmetric (f = 1/2) and asymmetric (f --> 0) regimes above and below the order-disorder transition. The consequences of fluctuations and access to equilibrium states will be described in the 1-dimensional stripped (lamellar) phase and the ordering of point particles in 3-dimensions, respectively. As N --> 1 computer simulation with realistic molecular detail becomes feasible presenting exciting opportunities to compliment the associated theoretical challenges. Research in collaboration with Sangwoo Lee, Chris Leighton and Timothy Gillard and Supported by NSF-DMR-1104368.

A methodology to determine boundary conditions from forced convection experiments using liquid crystal thermography

NASA Astrophysics Data System (ADS)

Jakkareddy, Pradeep S.; Balaji, C.

2017-02-01

This paper reports the results of an experimental study to estimate the heat flux and convective heat transfer coefficient using liquid crystal thermography and Bayesian inference in a heat generating sphere, enclosed in a cubical Teflon block. The geometry considered for the experiments comprises a heater inserted in a hollow hemispherical aluminium ball, resulting in a volumetric heat generation source that is placed at the center of the Teflon block. Calibrated thermochromic liquid crystal sheets are used to capture the temperature distribution at the front face of the Teflon block. The forward model is the three dimensional conduction equation which is solved within the Teflon block to obtain steady state temperatures, using COMSOL. Match up experiments are carried out for various velocities by minimizing the residual between TLC and simulated temperatures for every assumed loss coefficient, to obtain a correlation of average Nusselt number against Reynolds number. This is used for prescribing the boundary condition for the solution to the forward model. A surrogate model obtained by artificial neural network built upon the data from COMSOL simulations is used to drive a Markov Chain Monte Carlo based Metropolis Hastings algorithm to generate the samples. Bayesian inference is adopted to solve the inverse problem for determination of heat flux and heat transfer coefficient from the measured temperature field. Point estimates of the posterior like the mean, maximum a posteriori and standard deviation of the retrieved heat flux and convective heat transfer coefficient are reported. Additionally the effect of number of samples on the performance of the estimation process has been investigated.

An SRRC elliptically polarizing undulator prototype to examine mechanical design feasibility and magnetic field performance.

PubMed

Chang, C H; Hwang, C S; Fan, T C; Chen, K H; Pan, K T; Lin, F Y; Wang, C; Chang, L H; Chen, H H; Lin, M C; Yeh, S

1998-05-01

In this work, a 1 m long Sasaki-type elliptically polarizing undulator (EPU) prototype with 5.6 cm period length is used to examine the mechanical design feasibility as well as magnetic field performance. The magnetic field characteristics of the EPU5.6 prototype at various phase shifts and gap motion are described. The field errors from mechanical tolerances, magnet block errors, end field effects and phase/gap motion effects are analysed. The procedures related to correcting the field with the block position tuning, iron shimming and the trim blocks at both ends are outlined.

Atmospheric Blocking and Intercomparison of Objective Detection Methods: Flow Field Characteristics

NASA Astrophysics Data System (ADS)

Pinheiro, M. C.; Ullrich, P. A.; Grotjahn, R.

2017-12-01

A number of objective methods for identifying and quantifying atmospheric blocking have been developed over the last couple of decades, but there is variable consensus on the resultant blocking climatology. This project examines blocking climatologies as produced by three different methods: two anomaly-based methods, and the geopotential height gradient method of Tibaldi and Molteni (1990). The results highlight the differences in blocking that arise from the choice of detection method, with emphasis on the physical characteristics of the flow field and the subsequent effects on the blocking patterns that emerge.

Laboratory Study of Water Surface Roughness Generation by Wave-Current Interaction

NASA Technical Reports Server (NTRS)

Klinke, Jochen

2000-01-01

Within the framework of this project, the blocking of waves by inhomogeneous currents was studied. A laboratory experiment was conducted in collaboration with Steven R. Long at the linear wave tank of the NASA Air-Sea Interaction Facility, Wallops Island, VA during May 1999. Mechanically-generated waves were blocked approximately 3m upstream from the wave paddle by an opposing current. A false bottom was used to obtain a spatially varying flow field in the measurement section of the wave tank. We used an imaging slope gauge, which was mounted directly underneath the sloping section of the false tank bottom to observe the wave field. For a given current speed, the amplitude and the frequency of the waves was adjusted so that the blocking occurred within the observed footprint. Image sequences of up to 600 images at up 100 Hz sampling rate were recorded for an area of approximately 25cm x 25cm. Unlike previous measurements with wave wire gauges, the captured image sequences show the generation of the capillary waves at the blocking point and give detailed insight into the spatial and temporal evolution of the blocking process. The image data were used to study the wave-current interaction for currents from 5 to 25 cm/s and waves with frequencies between 1 and 3 Hz. First the images were calibrated with regard to size and slope. Then standard Fourier techniques as well the empirical mode decomposition method developed by Dr. Norden Huang and Dr. Steven R. Long were employed to quantify the wave number downshift from the gravity to the capillary regime.

Video image stabilization and registration--plus

NASA Technical Reports Server (NTRS)

Hathaway, David H. (Inventor)

2009-01-01

A method of stabilizing a video image displayed in multiple video fields of a video sequence includes the steps of: subdividing a selected area of a first video field into nested pixel blocks; determining horizontal and vertical translation of each of the pixel blocks in each of the pixel block subdivision levels from the first video field to a second video field; and determining translation of the image from the first video field to the second video field by determining a change in magnification of the image from the first video field to the second video field in each of horizontal and vertical directions, and determining shear of the image from the first video field to the second video field in each of the horizontal and vertical directions.

Rational synthesis of low-polydispersity block copolymer vesicles in concentrated solution via polymerization-induced self-assembly.

PubMed

Gonzato, Carlo; Semsarilar, Mona; Jones, Elizabeth R; Li, Feng; Krooshof, Gerard J P; Wyman, Paul; Mykhaylyk, Oleksandr O; Tuinier, Remco; Armes, Steven P

2014-08-06

Block copolymer self-assembly is normally conducted via post-polymerization processing at high dilution. In the case of block copolymer vesicles (or "polymersomes"), this approach normally leads to relatively broad size distributions, which is problematic for many potential applications. Herein we report the rational synthesis of low-polydispersity diblock copolymer vesicles in concentrated solution via polymerization-induced self-assembly using reversible addition-fragmentation chain transfer (RAFT) polymerization of benzyl methacrylate. Our strategy utilizes a binary mixture of a relatively long and a relatively short poly(methacrylic acid) stabilizer block, which become preferentially expressed at the outer and inner poly(benzyl methacrylate) membrane surface, respectively. Dynamic light scattering was utilized to construct phase diagrams to identify suitable conditions for the synthesis of relatively small, low-polydispersity vesicles. Small-angle X-ray scattering (SAXS) was used to verify that this binary mixture approach produced vesicles with significantly narrower size distributions compared to conventional vesicles prepared using a single (short) stabilizer block. Calculations performed using self-consistent mean field theory (SCMFT) account for the preferred self-assembled structures of the block copolymer binary mixtures and are in reasonable agreement with experiment. Finally, both SAXS and SCMFT indicate a significant degree of solvent plasticization for the membrane-forming poly(benzyl methacrylate) chains.

Use of abdominal field block injections with liposomal bupivicaine to control postoperative pain after abdominoplasty.

PubMed

Morales, Rolando; Mentz, Henry; Newall, Germán; Patronella, Christopher; Masters, Oscar

2013-11-01

It is well known that improving postoperative pain control in plastic surgery procedures leads to earlier mobilization, shortened hospital stay, reduced hospital costs, and increased patient satisfaction. The authors evaluate the use of abdominal field block injections with liposomal bupivicaine (Exparel; Pacira Pharmaceuticals, Inc, San Diego, California) in postoperative pain management in patients undergoing abdominoplasty with rectus plication. Case records from 64 female patients who underwent abdominoplasty with rectus plication were reviewed. We performed a total of 118 abdominoplasties with rectus plication, alone or in combination with other surgical procedures, from August 2012 to December 2012, but 54 patients were excluded from the series due to inadequate follow-up. Patients received liposomal bupivicaine injections in an abdominal field block fashion. Patient age, height, weight, and smoking status were recorded. Delivery of standardized postoperative intramuscular or intravenous injections and oral pain pills was recorded. Postoperative data and questionnaires were used to evaluate clinical efficacy. The average number of procedures (including abdominoplasty with rectus plication) per patient was 7. Average patient body mass index was 27 kg/m(2). Average pain scores were 3.5 (postoperative visit 1) and 2.8 (visit 2). The average number of oral pain pills required was 14 at the first postoperative visit and 11.5 at the second postoperative visit. Patients were able to resume normal activity at an average of 6.4 days. Our experience with liposomal bupivicaine injections for regional blocks in abdominoplasty with rectus plication indicates that patients experienced reduced postoperative pain, required less postoperative narcotic medication, and resumed both earlier ambulation and normal activity. Further investigation is warranted with more clinical cases to recommend the use of this medication for routine pain management after an abdominoplasty.

On the Kerr-AdS/CFT correspondence

NASA Astrophysics Data System (ADS)

Amado, Julián Barragán; da Cunha, Bruno Carneiro; Pallante, Elisabetta

2017-08-01

We review the relation between four-dimensional global conformal blocks and field propagation in AdS5. Following the standard argument that marginal perturbations should backreact in the geometry, we turn to the study of scalar fields in the generic Kerr-AdS5 geometry. On one hand, the result for scattering coefficients can be obtained exactly using the isomonodromy technique, giving exact expressions in terms of c = 1 chiral conformal blocks. On the other hand, one can use the analogy between the scalar field equations to the Level 2 null field Ward identity in two dimensional Liouville field theory to write approximate expressions for the same coefficients in terms of semi-classical chiral Liouville conformal blocks. Surprisingly, the conformal block thus constructed has a well-behaved interpretation in terms of Liouville vertex operators.

Pure-type superconducting permanent-magnet undulator.

PubMed

Tanaka, Takashi; Tsuru, Rieko; Kitamura, Hideo

2005-07-01

A novel synchrotron radiation source is proposed that utilizes bulk-type high-temperature superconductors (HTSCs) as permanent magnets (PMs) by in situ magnetization. Arrays of HTSC blocks magnetized by external magnetic fields are placed below and above the electron path instead of conventional PMs, generating a periodic magnetic field with an offset. Two methods are presented to magnetize the HTSCs and eliminate the field offset, enabling the HTSC arrays to work as a synchrotron radiation source. An analytical formula to calculate the peak field achieved in a device based on this scheme is derived in a two-dimensional form for comparison with synchrotron radiation sources using conventional PMs. Experiments were performed to demonstrate the principle of the proposed scheme and the results have been found to be very promising.

An air transfer experiment confirms the role of volatile cues in communication between plants.

PubMed

Karban, Richard; Shiojiri, Kaori; Ishizaki, Satomi

2010-09-01

Previous studies reported that sagebrush plants near experimentally clipped neighbors experienced less herbivory than did plants near unclipped neighbors. Blocking air flow with plastic bags made this effect undetectable. However, some scientists remained skeptical about the possibility of volatile communication between plants since the existence and identity of a cue that operates in nature have never been demonstrated. We conducted an air transfer experiment that collected air from the headspace of an experimentally clipped donor plant and delivered it to the headspace of an unclipped assay plant. We found that assay plants treated with air from clipped donors were less likely to be damaged by naturally occurring herbivores in a field experiment. This simple air transfer experiment fulfills the most critical of Koch's postulates and provides more definitive evidence for volatile communication between plants. It also provides an inexpensive experimental protocol that can be used to screen plants for interplant communication in the field.

The proximate unit in Chinese handwritten character production

PubMed Central

Chen, Jenn-Yeu; Cherng, Rong-Ju

2013-01-01

In spoken word production, a proximate unit is the first phonological unit at the sublexical level that is selectable for production (O'Seaghdha et al., 2010). The present study investigated whether the proximate unit in Chinese handwritten character production is the stroke, the radical, or something in between. A written version of the form preparation task was adopted. Chinese participants learned sets of two-character words, later were cued with the first character of each word, and had to write down the second character (the target). Response times were measured from the onset of a cue character to the onset of a written response. In Experiment 1, the target characters within a block shared (homogeneous) or did not share (heterogeneous) the first stroke. In Experiment 2, the first two strokes were shared in the homogeneous blocks. Response times in the homogeneous blocks and in the heterogeneous blocks were comparable in both experiments (Experiment 1: 687 vs. 684 ms, Experiment 2: 717 vs. 716). In Experiment 3 and 4, the target characters within a block shared or did not share the first radical. Response times in the homogeneous blocks were significantly faster than those in the heterogeneous blocks (Experiment 3: 685 vs. 704, Experiment 4: 594 vs. 650). In Experiment 5 and 6, the shared component was a Gestalt-like form that is more than a stroke, constitutes a portion of the target character, can be a stand-alone character itself, can be a radical of another character but is not a radical of the target character (e.g., ± in , , , ; called a logographeme). Response times in the homogeneous blocks were significantly faster than those in the heterogeneous blocks (Experiment 5: 576 vs. 625, Experiment 6: 586 vs. 620). These results suggest a model of Chinese handwritten character production in which the stroke is not a functional unit, the radical plays the role of a morpheme, and the logographeme is the proximate unit. PMID:23950752

Experiments- Skylab General (Apollo Telescope Mount) S082

NASA Image and Video Library

2013-10-23

S74-15583 (July 1973) --- A huge solar eruption can be seen in this Spectroheliogram obtained during the Skylab 3 mission by the Extreme Ultraviolet Spectrograph/Spectroheliograph SO82A Experiment aboard the Skylab space station in Earth orbit. SO82 is one of the Apollo Telescope Mount experiments. The SO82 "A" instrument covers the wavelength region from 150-650 angstroms (EUV regions). The magnitude of the eruption can be visualized by comparing it with the small white dot that represents the size of Earth. This photograph reveals for the first time that helium erupting from the sun can stay together to altitudes of up to 500,000 miles. After being ejected from the sun, the gas clouds seem to have come to a standstill, as though blocked by an unseen wall. Some materials appear to have been directed back toward the sun as a rain, distinguished by fine threads. At present it is a challenge to explain this mystery--what forces expelled these huge clouds, then blocked its further progress, yet allowed the cloud to maintain its threads. Both magnetic fields and gravity must play a part, but these curious forms seem to defy explanation based on magnetic and gravitational fields alone. The EUV spectroheliograph was designed and constructed by the U.S. Naval Research Laboratory and the Ball Brothers Research Corporation under the direction of Dr. R. Tousey, the principal investigator for this NASA experiment. On the left may be seen the sun's image in emission from iron atoms which have lost 14 electrons by collision in the sun's million-degree coronal plasma gas. Photo credit: NASA

The Precision Field Lysimeter Concept

NASA Astrophysics Data System (ADS)

Fank, J.

2009-04-01

The understanding and interpretation of leaching processes have improved significantly during the past decades. Unlike laboratory experiments, which are mostly performed under very controlled conditions (e.g. homogeneous, uniform packing of pre-treated test material, saturated steady-state flow conditions, and controlled uniform hydraulic conditions), lysimeter experiments generally simulate actual field conditions. Lysimeters may be classified according to different criteria such as type of soil block used (monolithic or reconstructed), drainage (drainage by gravity or vacuum or a water table may be maintained), or weighing or non-weighing lysimeters. In 2004 experimental investigations have been set up to assess the impact of different farming systems on groundwater quality of the shallow floodplain aquifer of the river Mur in Wagna (Styria, Austria). The sediment is characterized by a thin layer (30 - 100 cm) of sandy Dystric Cambisol and underlying gravel and sand. Three precisely weighing equilibrium tension block lysimeters have been installed in agricultural test fields to compare water flow and solute transport under (i) organic farming, (ii) conventional low input farming and (iii) extensification by mulching grass. Specific monitoring equipment is used to reduce the well known shortcomings of lysimeter investigations: The lysimeter core is excavated as an undisturbed monolithic block (circular, 1 m2 surface area, 2 m depth) to prevent destruction of the natural soil structure, and pore system. Tracing experiments have been achieved to investigate the occurrence of artificial preferential flow and transport along the walls of the lysimeters. The results show that such effects can be neglected. Precisely weighing load cells are used to constantly determine the weight loss of the lysimeter due to evaporation and transpiration and to measure different forms of precipitation. The accuracy of the weighing apparatus is 0.05 kg, or 0.05 mm water equivalent respectively. The different soil horizons in the lysimeters are equipped with sensors to measure soil temperature, water content and soil tension. Suction cups are used to get soil water samples. The lower boundary of the lysimeter is designed to maintain equilibrium between the suction applied to the leachate collection system and soil matrix potential thus the suction applied may vary depending on natural conditions - measured using tensiometers - in the field. The lysimeters are built in directly in a test area of 1000 m2 with the same vegetation to prevent island effects on evotranspiration. The topmost part of the lysimeter is realized as a removable ring that mechanical cultivation is possible in the same manner as at the test field. In this presentation the concept and the implementation of the Precision Field Lysimeter is shown. First results on water and solute balances of a 4 years investigation period are discussed.

Control of Biosonar Behavior by the Auditory Cortex

DTIC Science & Technology

1988-11-28

TITLE (include Security Classification) Control of Biosonar Behavior by the Auditory Cortex 12. PERSONAL AUTHOR(S) Nobuo Suga and Stephen Gaioni 13a...NOTATION 17. COSATI CODES IS SUBJECT TERMS (Continue on reverse if necessary and identify by block number) FIELD GROUP1 SUB-GROUP - biosonar ; echolocation...SLesion experiments were conducted to examine whether the functional organization of the mustached bat’s auditory cortex is related to biosonar

Amphibian and reptile responses to thinning and prescribed burning in mixed pine-hardwood forests of northwestern Alabama, USA

Treesearch

William B. Sutton; Yong Wang; Callie J. Schweitzer

2013-01-01

We evaluated the response of amphibians and reptiles to two levels of prescribed burning and three levels of thinning using a field experiment consisting of a before–after, control-impact, and factorial complete block design over a four year period in the William B. Bankhead National Forest located in northwestern Alabama. We captured 2643 individuals representing 47...

Computer Simulation and Field Experiment for Downlink Multiuser MIMO in Mobile WiMAX System.

PubMed

Yamaguchi, Kazuhiro; Nagahashi, Takaharu; Akiyama, Takuya; Matsue, Hideaki; Uekado, Kunio; Namera, Takakazu; Fukui, Hiroshi; Nanamatsu, Satoshi

2015-01-01

The transmission performance for a downlink mobile WiMAX system with multiuser multiple-input multiple-output (MU-MIMO) systems in a computer simulation and field experiment is described. In computer simulation, a MU-MIMO transmission system can be realized by using the block diagonalization (BD) algorithm, and each user can receive signals without any signal interference from other users. The bit error rate (BER) performance and channel capacity in accordance with modulation schemes and the number of streams were simulated in a spatially correlated multipath fading environment. Furthermore, we propose a method for evaluating the transmission performance for this downlink mobile WiMAX system in this environment by using the computer simulation. In the field experiment, the received power and downlink throughput in the UDP layer were measured on an experimental mobile WiMAX system developed in Azumino City in Japan. In comparison with the simulated and experimented results, the measured maximum throughput performance in the downlink had almost the same performance as the simulated throughput. It was confirmed that the experimental mobile WiMAX system for MU-MIMO transmission successfully increased the total channel capacity of the system.

Computer Simulation and Field Experiment for Downlink Multiuser MIMO in Mobile WiMAX System

PubMed Central

Yamaguchi, Kazuhiro; Nagahashi, Takaharu; Akiyama, Takuya; Matsue, Hideaki; Uekado, Kunio; Namera, Takakazu; Fukui, Hiroshi; Nanamatsu, Satoshi

2015-01-01

The transmission performance for a downlink mobile WiMAX system with multiuser multiple-input multiple-output (MU-MIMO) systems in a computer simulation and field experiment is described. In computer simulation, a MU-MIMO transmission system can be realized by using the block diagonalization (BD) algorithm, and each user can receive signals without any signal interference from other users. The bit error rate (BER) performance and channel capacity in accordance with modulation schemes and the number of streams were simulated in a spatially correlated multipath fading environment. Furthermore, we propose a method for evaluating the transmission performance for this downlink mobile WiMAX system in this environment by using the computer simulation. In the field experiment, the received power and downlink throughput in the UDP layer were measured on an experimental mobile WiMAX system developed in Azumino City in Japan. In comparison with the simulated and experimented results, the measured maximum throughput performance in the downlink had almost the same performance as the simulated throughput. It was confirmed that the experimental mobile WiMAX system for MU-MIMO transmission successfully increased the total channel capacity of the system. PMID:26421311

Characterization of granular collapse onto hard substrates by acoustic emissions

NASA Astrophysics Data System (ADS)

Farin, Maxime; Mangeney, Anne; Toussaint, Renaud; De Rosny, Julien

2013-04-01

Brittle deformation in granular porous media can generate gravitational instabilities such as debris flows and rock avalanches. These phenomena constitute a major natural hazard for the population in mountainous, volcanic and coastal areas but their direct observation on the field is very dangerous. Recent studies showed that gravitational instabilities can be detected and characterized (volume, duration,...) thanks to the seismic signal they generate. In an avalanche, individual block bouncing and rolling on the ground are expected to generated signals of higher frequencies than the main flow spreading. The identification of the time/frequency signature of individual blocks in the recorded signal remains however difficult. Laboratory experiments were conducted to investigate the acoustic signature of diverse simple sources corresponding to grains falling over thin plates of plexiglas and rock blocks. The elastic energy emitted by a single bouncing steel bead into the support was first quantitatively estimated and compared to the potential energy of fall and to the potential energy change during the shock. Next, we consider the collapse of granular columns made of steel spherical beads onto hard substrates. Initially, these columns were held by a magnetic field allowing to suppress suddenly the cohesion between the beads, and thus to minimize friction effects that would arise from side walls. We varied systematically the column volume, the column aspect ratio (height over length) and the grain size. This is shown to affect the signal envelope and frequency content. In the experiments, two types of acoustic sensors were used to record the signals in a wide frequency range: accelerometers (1 Hz to 56 kHz) and piezoelectric sensors (100 kHz to 1 MHz). The experiments were also monitored optically using fast cameras. We developed a technique to use quantitatively both types of sensors to evaluate the elastic energy emitted by the sources. Eventually, we looked at what types of features in the signal are affected by individual shocks or by the large scale geometry of the avalanche.

Accretion shocks in the laboratory: Design of an experiment to study star formation

DOE PAGES

Young, Rachel P.; Kuranz, C. C.; Drake, R. P.; ...

2017-02-13

Here, we present the design of a laboratory-astrophysics experiment to study magnetospheric accretion relevant to young, pre-main-sequence stars. Spectra of young stars show evidence of hotspots created when streams of accreting material impact the surface of the star and create shocks. The structures that form during this process are poorly understood, as the surfaces of young stars cannot be spatially resolved. Our experiment would create a scaled "accretion shock" at a major (several kJ) laser facility. The experiment drives a plasma jet (the "accretion stream") into a solid block (the "stellar surface"), in the presence of a parallel magnetic fieldmore » analogous to the star's local field.« less

Morphology of Block Copolymer Electrolytes: A Numerical Self-Consistent Field Theory Study

NASA Astrophysics Data System (ADS)

Hou, Kevin; Qin, Jian

Engineering the morphology of ion-containing block copolymers is imperative for the optimization of their charge-transport and mechanical properties. Existing experiments have demonstrated that the addition of ions has a dramatic effect on the morphology and thermodynamic behavior of these structured electrolytes. We have developed an efficient, symmetry-adapted algorithm to calculate the ionic interactions in the SCFT for ion-containing polymers. We present the results of a numerical SCFT study examining how dielectric heterogeneity, ion concentration, and ion solvation affect morphology, domain spacing, ion distribution, and polymer density profiles. Particular attention is given to the detailed morphological analysis of the bicontinuous gyroidal phase, as well as the relevance of the aforementioned results to ionic conductivity.

Non-oscillatory central differencing for hyperbolic conservation laws

NASA Technical Reports Server (NTRS)

Nessyahu, Haim; Tadmor, Eitan

1988-01-01

Many of the recently developed high resolution schemes for hyperbolic conservation laws are based on upwind differencing. The building block for these schemes is the averaging of an appropriate Godunov solver; its time consuming part involves the field-by-field decomposition which is required in order to identify the direction of the wind. Instead, the use of the more robust Lax-Friedrichs (LxF) solver is proposed. The main advantage is simplicity: no Riemann problems are solved and hence field-by-field decompositions are avoided. The main disadvantage is the excessive numerical viscosity typical to the LxF solver. This is compensated for by using high-resolution MUSCL-type interpolants. Numerical experiments show that the quality of results obtained by such convenient central differencing is comparable with those of the upwind schemes.

Rheological Properties of Natural Subduction Zone Interface: Insights from "Digital" Griggs Experiments

NASA Astrophysics Data System (ADS)

Ioannidi, P. I.; Le Pourhiet, L.; Moreno, M.; Agard, P.; Oncken, O.; Angiboust, S.

2017-12-01

The physical nature of plate locking and its relation to surface deformation patterns at different time scales (e.g. GPS displacements during the seismic cycle) can be better understood by determining the rheological parameters of the subduction interface. However, since direct rheological measurements are not possible, finite element modelling helps to determine the effective rheological parameters of the subduction interface. We used the open source finite element code pTatin to create 2D models, starting with a homogeneous medium representing shearing at the subduction interface. We tested several boundary conditions that mimic simple shear and opted for the one that best describes the Grigg's type simple shear experiments. After examining different parameters, such as shearing velocity, temperature and viscosity, we added complexity to the geometry by including a second phase. This arises from field observations, where shear zone outcrops are often composites of multiple phases: stronger crustal blocks embedded within a sedimentary and/or serpentinized matrix have been reported for several exhumed subduction zones. We implemented a simplified model to simulate simple shearing of a two-phase medium in order to quantify the effect of heterogeneous rheology on stress and strain localization. Preliminary results show different strength in the models depending on the block-to-matrix ratio. We applied our method to outcrop scale block-in-matrix geometries and by sampling at different depths along exhumed former subduction interfaces, we expect to be able to provide effective friction and viscosity of a natural interface. In a next step, these effective parameters will be used as input into seismic cycle deformation models in an attempt to assess the possible signature of field geometries on the slip behaviour of the plate interface.

DiMES Tests of W Leading Edge Power Loading in DIII-D

NASA Astrophysics Data System (ADS)

Nygren, R. E.; Watkins, J. G.; Rudakov, D. L.; Lasnier, C. J.; Pitts, R. A.; Stangeby, P. C.

2015-11-01

In a transient melt experiment in JET, the power to a ~1-mm-high leading edge on a W lamella in the bulk-W outer divertor was lower than expected from the geometry by factors of 5 and 2 for L-mode and H-mode discharges, respectively. We checked this surprising result in DIII-D with 3 W blocks (10 mm square) mounted radially side-by-side in DiMES with leading edges of 0.0, 0.3, 1.0 mm, single null L-mode plasmas, OSP just outside ``0.0'' block, limited scans (NBI+ECH), B-field incident at 1.5° or 2.5°, and viewed, as in JET, from above with 0.2mm/pixel resolution IRTV. Langmuir probes measured parallel power to the target. We compared probe and IR data with a detailed thermal model of the blocks and concluded provisionally that we did not reproduce the power deficit found in JET. Blurred IR images complicated fitting of temperature distributions from the thermal model. We plan an experiment with both L- and H-mode He plasmas before the APS meeting. Supported by US DOE under DE-AC04-94AL85000, 44500007360, DE-AC52-07NA27344, and DE-FC02-04ER54698.

The Design, Fabrication and Characterization of a Transparent Atom Chip

PubMed Central

Chuang, Ho-Chiao; Huang, Chia-Shiuan; Chen, Hung-Pin; Huang, Chi-Sheng; Lin, Yu-Hsin

2014-01-01

This study describes the design and fabrication of transparent atom chips for atomic physics experiments. A fabrication process was developed to define the wire patterns on a transparent glass substrate to create the desired magnetic field for atom trapping experiments. An area on the chip was reserved for the optical access, so that the laser light can penetrate directly through the glass substrate for the laser cooling process. Furthermore, since the thermal conductivity of the glass substrate is poorer than other common materials for atom chip substrate, for example silicon, silicon carbide, aluminum nitride. Thus, heat dissipation copper blocks are designed on the front and back of the glass substrate to improve the electrical current conduction. The testing results showed that a maximum burnout current of 2 A was measured from the wire pattern (with a width of 100 μm and a height of 20 μm) without any heat dissipation design and it can increase to 2.5 A with a heat dissipation design on the front side of the atom chips. Therefore, heat dissipation copper blocks were designed and fabricated on the back of the glass substrate just under the wire patterns which increases the maximum burnout current to 4.5 A. Moreover, a maximum burnout current of 6 A was achieved when the entire backside glass substrate was recessed and a thicker copper block was electroplated, which meets most requirements of atomic physics experiments. PMID:24922456

Examining the Self-Assembly of Rod-Coil Block Copolymers via Physics Based Polymer Models and Polarized X-Ray Scattering

NASA Astrophysics Data System (ADS)

Hannon, Adam; Sunday, Daniel; Windover, Donald; Liman, Christopher; Bowen, Alec; Khaira, Gurdaman; de Pablo, Juan; Delongchamp, Dean; Kline, R. Joseph

Photovoltaics, flexible electronics, and stimuli-responsive materials all require enhanced methodology to examine their nanoscale molecular orientation. The mechanical, electronic, optical, and transport properties of devices made from these materials are all a function of this orientation. The polymer chains in these materials are best modeled as semi-flexible to rigid rods. Characterizing the rigidity and molecular orientation of these polymers non-invasively is currently being pursued by using polarized resonant soft X-ray scattering (P-RSoXS). In this presentation, we show recent work on implementing such a characterization process using a rod-coil block copolymer system in the rigid-rod limit. We first demonstrate how we have used physics based models such as self-consistent field theory (SCFT) in non-polarized RSoXS work to fit scattering profiles for thin film coil-coil PS- b-PMMA block copolymer systems. We then show by using a wormlike chain partition function in the SCFT formulism to model the rigid-rod block, the methodology can be used there as well to extract the molecular orientation of the rod block from a simulated P-RSoXS experiment. The results from the work show the potential of the technique to extract thermodynamic and morphological sample information.

The computation of 15 deg and 10 deg equal area block terrestrial free air gravity anomalies

NASA Technical Reports Server (NTRS)

Hajela, D. P.

1973-01-01

Starting with the set of 23,355 1 deg x 1 deg mean free air gravity anomalies used in Rapp (1972) to form a 5 deg equal area block terrestrial gravity field, the computation of 15 deg equal area block mean free air gravity anomalies is described along with estimates of their standard deviations. A new scheme of an integral division of a 15 deg block into 9 component 300 n. m. blocks, and each 300 n. m. block being subdivided into 25 60 n.mi. blocks, is used. This insures that there is no loss in accuracy, which would have resulted if proportional values according to area were taken of the 5 deg equal area anomalies to form the 15 deg block anomalies. A similar scheme is used for the computation of 10 deg equal area block mean free air gravity anomalies with estimates of their standard deviations. The scheme is general enough to be used for a 30 deg equal area block terrestrial gravity field.

Adsorption of oils, heavy metals and dyes by recovered carbon powder from spent pot liner of aluminum smelter plant.

PubMed

Mazumder, B; Devi, Sasmita Rani

2008-07-01

Aluminum smelter plants employ Hall-Heroult electrolysis cells for electrolysis of molten cryolite to recover aluminum metal by electrolysis. These cells use carbon cathode blocks as a lining material inside. At the end of service life of the cells, pot lines are discarded and new carbon blocks are laid for fresh charging. These used carbon cathode blocks, known as spent pot liners, are heavily infested with toxic elements such as fluoride, cyanide, alkali, etc. Therefore, their disposal in open field poses great environmental risk. A simple process has been developed for decontamination of these spent pot liners and to recover its carbon value. The experiments indicated that this carbon, in the form of fine powder (around 20 micron in size) can absorb toxic elements like heavy metals, dyes, oils, etc. to a great extent and thus can be used for mitigating environmental pollution occuring due to various toxic wastes.

Fractured rock stress-permeability relationships from in situ data and effects of temperature and chemical-mechanical couplings

DOE PAGES

Rutqvist, J.

2014-09-19

The purpose of this paper is to (i) review field data on stress-induced permeability changes in fractured rock; (ii) describe estimation of fractured rock stress-permeability relationships through model calibration against such field data; and (iii) discuss observations of temperature and chemically mediated fracture closure and its effect on fractured rock permeability. The field data that are reviewed include in situ block experiments, excavation-induced changes in permeability around tunnels, borehole injection experiments, depth (and stress) dependent permeability, and permeability changes associated with a large-scale rock-mass heating experiment. Data show how the stress-permeability relationship of fractured rock very much depends on localmore » in situ conditions, such as fracture shear offset and fracture infilling by mineral precipitation. Field and laboratory experiments involving temperature have shown significant temperature-driven fracture closure even under constant stress. Such temperature-driven fracture closure has been described as thermal overclosure and relates to better fitting of opposing fracture surfaces at high temperatures, or is attributed to chemically mediated fracture closure related to pressure solution (and compaction) of stressed fracture surface asperities. Back-calculated stress-permeability relationships from field data may implicitly account for such effects, but the relative contribution of purely thermal-mechanical and chemically mediated changes is difficult to isolate. Therefore, it is concluded that further laboratory and in situ experiments are needed to increase the knowledge of the true mechanisms behind thermally driven fracture closure, and to further assess the importance of chemical-mechanical coupling for the long-term evolution of fractured rock permeability.« less

Fractured rock stress-permeability relationships from in situ data and effects of temperature and chemical-mechanical couplings

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

Rutqvist, J.

The purpose of this paper is to (i) review field data on stress-induced permeability changes in fractured rock; (ii) describe estimation of fractured rock stress-permeability relationships through model calibration against such field data; and (iii) discuss observations of temperature and chemically mediated fracture closure and its effect on fractured rock permeability. The field data that are reviewed include in situ block experiments, excavation-induced changes in permeability around tunnels, borehole injection experiments, depth (and stress) dependent permeability, and permeability changes associated with a large-scale rock-mass heating experiment. Data show how the stress-permeability relationship of fractured rock very much depends on localmore » in situ conditions, such as fracture shear offset and fracture infilling by mineral precipitation. Field and laboratory experiments involving temperature have shown significant temperature-driven fracture closure even under constant stress. Such temperature-driven fracture closure has been described as thermal overclosure and relates to better fitting of opposing fracture surfaces at high temperatures, or is attributed to chemically mediated fracture closure related to pressure solution (and compaction) of stressed fracture surface asperities. Back-calculated stress-permeability relationships from field data may implicitly account for such effects, but the relative contribution of purely thermal-mechanical and chemically mediated changes is difficult to isolate. Therefore, it is concluded that further laboratory and in situ experiments are needed to increase the knowledge of the true mechanisms behind thermally driven fracture closure, and to further assess the importance of chemical-mechanical coupling for the long-term evolution of fractured rock permeability.« less

Environmental and Water Quality Operational Studies. Environmental Guidelines for Dike Fields.

DTIC Science & Technology

1984-09-01

public release; distribution unlimited. I. DISTRIBUTION STATEMENT (of the abstract entered In Block 20, If different from Report) IS. SUPPLEMENTARY NOTES...necessary and identify by block number) Aquatic biology--Environmental aspects. (LC) Dikes (Engineering)--Design and construction--Environmental...w ad Idenwify by block number) ’The environmental guidelines for dike fields-contained within this report consist of environmental objectives, design

Thermally Assisted Macroscopic Quantum Resonance on a Single-Crystal of Mn12-ac

NASA Astrophysics Data System (ADS)

Lionti, F.; Thomas, L.; Ballou, R.; Wernsdorfer, W.; Barbara, B.; Sulpice, A.; Sessoli, R.; Gatteschi, D.

1997-03-01

Magnetization measurements have been performed on a single mono-crystal of the molecule Mn12-acetate (L. Thomas, F. Lionti, R. Ballou, R. Sessoli, D. Gatteschi and B. Barbara, Nature, 383, 145 (1996).). Steps were observed in the hysteresis loop for values of the applied field at which level crossings of the collective spin states of each manganese clusters take place. The influence of quartic terms is taken into account. At these fields, the magnetization relaxes at short time scales, being otherwise essentially blocked. This novel behavior is interpreted in terms of resonant quantum tunneling of the magnetization from thermally activated energy levels. Hysteresis loop measurements performed for different field orientations and ac-susceptibility experiments, confirm general trends of this picture.

Cross-field electron transport inside an insulating cylinder of a baffled probe

NASA Astrophysics Data System (ADS)

Raitses, Yevgeny; Alt, Andrew

2017-10-01

Plasma-immersed wall experiments have been performed in a magnetized xenon plasma in a cross-field Penning configuration with density around 1012 cm-3 and an electron temperature around a few eV. A cylinder with an open end and diameter of 1.4 mm was placed across field lines so that electrons were blocked from reaching a wire recessed behind the shield while ions were unimpeded. The reduction of electron current to the wire causes it to float closer to the plasma potential, possibly making a device that can passively measure plasma potential. However, the measured electron current was much higher than expected even when the wire was recessed several electron gyroradii behind the baffle. Possible mechanisms for this electron conduction causing the short circuiting to the bulk plasma have been studied with numerical approaches and with a dedicated experiment designed to isolate this short circuit effect. The obtained results may be important for cross-field transport in a variety of other configurations in magnetized, low-temperature plasmas. This work was supported by DOE contract DE-AC02-09CH11466.

Teleoperation in surgical robotics--network latency effects on surgical performance.

PubMed

Lum, Mitchell J H; Rosen, Jacob; King, Hawkeye; Friedman, Diana C W; Lendvay, Thomas S; Wright, Andrew S; Sinanan, Mika N; Hannaford, Blake

2009-01-01

A teleoperated surgical robotic system allows surgical procedures to be conducted across long distances while utilizing wired and wireless communication with a wide spectrum of performance that may affect the outcome. An open architecture portable surgical robotic system (Raven) was developed for both open and minimally invasive surgery. The system has been the subject of an intensive telesurgical experimental protocol aimed at exploring the boundaries of the system and surgeon performance during a series of field experiments in extreme environments (desert and underwater) teleportation between US, Europe, and Japan as well as lab experiments under synthetic fixed time delay. One standard task (block transfer emulating tissue manipulation) of the Fundamentals of Laparoscopic Surgery (FLS) training kit was used for the experimental protocol. Network characterization indicated a typical time delay in the range of 16-172 ms in field experiments. The results of the lab experiments showed that the completion time of the task as well as the length of the tool tip trajectory significantly increased (alpha< 0.02) as time delay increased in the range of 0-0.5 sec increased. For teleoperation with a time delay of 0.25s and 0.5s the task completion time was lengthened by a factor of 1.45 and 2.04 with respect to no time delay, whereas the length of the tools' trajectory was increased by a factor of 1.28 and 1.53 with respect to no time delay. There were no statistical differences between experienced surgeons and non-surgeons in the number of errors (block drooping) as well as the completion time and the tool tip path length at different time delays.

A Bullet-Block Experiment That Explains the Chain Fountain

ERIC Educational Resources Information Center

Pantaleone, J.; Smith, R.

2018-01-01

It is common in science for two phenomena to appear to be very different, but in fact follow from the same basic principles. Here we consider such a case, the connection between the chain fountain and a bullet-block collision experiment. When an upward moving bullet strikes a wooden block resting on a horizontal table, the block will rise to a…

Preservation of within-compound associations after blocked preexposure to two compound flavors.

PubMed

Espinet, Alfredo; Caramés, José M; Cabo, Fernando

2015-11-01

Three experiments investigated the extinction of the within-compound A↔X association established when two compound flavors, AX and BX, are preexposed in blocks (i.e., AX, AX, AX, ... BX, BX, BX). In Experiment 1, a group of rats received preexposure to a block of AX trials followed by a second block of BX trials (AX-BX), while a second group received blocked preexposure to the same stimuli in the opposite order (BX-AX). Subsequently, flavor A was paired with lithium chloride. This conditioning resulted in a similar reduction of consumption of flavor X in both groups. In Experiment 2 four groups of rats received blocked preexposure to AX-BX, AX-B, A-BX, or A-X. After aversive conditioning of X, consumption of A and B was significantly lower for the groups which received these flavors paired with X than for the groups for which these flavors were presented isolated. In Experiment 3 a group of rats was preexposed to a block of SaltX presentations followed by a block of BX presentations (SaltX-BX), and a second group received blocked preexposure to (BX-SaltX). After subsequent sodium depletion, consumption of X was high and similar for the SaltX-BX and for the BX-SaltX groups. These results indicate that the within-compound association established in the first block of a blocked preexposure is not extinguished when the preexposure phase is concluded. Copyright © 2015 Elsevier B.V. All rights reserved.

A Bullet-Block Experiment that Explains the Chain Fountain

NASA Astrophysics Data System (ADS)

Pantaleone, J.; Smith, R.

2018-05-01

It is common in science for two phenomena to appear to be very different, but in fact follow from the same basic principles. Here we consider such a case, the connection between the chain fountain and a bullet-block collision experiment. When an upward moving bullet strikes a wooden block resting on a horizontal table, the block will rise to a higher height when the bullet strikes near the end of the block. This is because the quickly rotating block experiences an additional upward "reaction" force from its contact with the table. Such a reaction force also explains the chain fountain. When a chain falls from a pile in a container to the floor below, the chain rises up above the container. This rise occurs because the quickly rotating links in the container push off of the surface beneath them. We derive a model that accurately describes our measurements in the bullet-block experiment, and then use this same model to calculate an approximate expression for the distance the chain rises above the container. More extensive discussions of the chain fountain are available elsewhere.

Surface plasmon enhanced cell microscopy with blocked random spatial activation

NASA Astrophysics Data System (ADS)

Son, Taehwang; Oh, Youngjin; Lee, Wonju; Yang, Heejin; Kim, Donghyun

2016-03-01

We present surface plasmon enhanced fluorescence microscopy with random spatial sampling using patterned block of silver nanoislands. Rigorous coupled wave analysis was performed to confirm near-field localization on nanoislands. Random nanoislands were fabricated in silver by temperature annealing. By analyzing random near-field distribution, average size of localized fields was found to be on the order of 135 nm. Randomly localized near-fields were used to spatially sample F-actin of J774 cells (mouse macrophage cell-line). Image deconvolution algorithm based on linear imaging theory was established for stochastic estimation of fluorescent molecular distribution. The alignment between near-field distribution and raw image was performed by the patterned block. The achieved resolution is dependent upon factors including the size of localized fields and estimated to be 100-150 nm.

Evaluation of non-selective refocusing pulses for 7 T MRI

PubMed Central

Moore, Jay; Jankiewicz, Marcin; Anderson, Adam W.; Gore, John C.

2011-01-01

There is a continuing need for improved RF pulses that achieve proper refocusing in the context of ultra-high field (≥ 7 T) human MRI. Simple block or sinc pulses are highly susceptible to RF field inhomogeneities, and adiabatic pulses are generally considered too SAR intensive for practical use at 7 T. The performance of the array of pulses falling between these extremes, however, has not been systematically evaluated. The aim of this work was to compare the performances of 21 non-selective refocusing pulses spanning a range of durations and SAR levels. The evaluation was based upon simulations and both phantom and in vivo human brain experiments conducted at 7 T. Tested refocusing designs included block, composite block, BIR-4, hyperbolic secant, and numerically optimized composite waveforms. These pulses were divided into three SAR classes and two duration categories, and, based on signal gain in a 3-D spin echo sequence, practical recommendations on usage are made within each category. All evaluated pulses were found to produce greater volume-averaged signals relative to a 180° block pulse. Although signal gains often come with the price of increased SAR or duration, some pulses were found to result in significant signal enhancement while also adhering to practical constraints. This work demonstrates the signal gains and losses realizable with single-channel refocusing pulse designs and should assist in the selection of suitable refocusing pulses for practical 3-D spin-echo imaging at 7 T. It further establishes a reference against which future pulses and multi-channel designs can be compared. PMID:22177384

Why does carbon increase in highly weathered soil under no-till upon lime and gypsum use?

PubMed

Inagaki, Thiago Massao; de Moraes Sá, João Carlos; Caires, Eduardo Fávero; Gonçalves, Daniel Ruiz Potma

2017-12-01

Field experiments have been used to explain how soil organic carbon (SOC) dynamics is affected by lime and gypsum applications, however, how SOC storage occurs is still debatable. We hypothesized that although many studies conclude that Ca-based soil amendments such as lime and gypsum may lead to SOC depletion due to the enhancement of microbial activity, the same does not occur under conservation agriculture conditions. Thus, the objective of this study was to elucidate the effects of lime and gypsum applications on soil microbial activity and SOC stocks in a no-till field and in a laboratory incubation study simulating no-till conditions. The field experiment was established in 1998 in a clayey Oxisol in southern Brazil following a completely randomized blocks design with a split-plot arrangement and three replications. Lime and gypsum were surface applied in 1998 and reapplied in 2013. Undisturbed soil samples were collected before the treatments reapplications, and one year after. The incubation experiment was carried out during 16months using these samples adding crop residues on the soil surface to simulate no-till field conditions. Lime and gypsum applications significantly increased the labile SOC stocks, microbial activity and soil fertility attributes in both field and laboratory experiments. Although the microbial activity was increased, no depletion of SOC stocks was observed in both experiments. Positive correlations were observed between microbial activity increase and SOC gains. Labile SOC and Ca 2+ content increase leads to forming complex with mineral soil fractions. Gypsum applications performed a higher influence on labile SOC pools in the field than in the laboratory experiment, which may be related to the presence of active root system in the soil profile. We conclude that incubation experiments using lime and gypsum in undisturbed samples confirm that soil microbial activity increase does not deplete SOC stocks under conservation agriculture. Copyright © 2017 Elsevier B.V. All rights reserved.

Emission Factors of Nitrous Oxide by Organic Manure Fertilizers in Japanese Upland Fields

NASA Astrophysics Data System (ADS)

Sudo, S.

2011-12-01

Preliminary data of field experiments which were conducted to estimate emission factors of nitrous oxide by organic manure fertilizers in 10 Japan-wide experiment sites, 2010 was reported. We compared nitrous oxide emission from urea as chemical fertilizers and cow manure as organic applications, in 1o Japanese prefectures of Yamagata, Fukushima, Ibaraki, Aichi, Shiga, Tokushima, Nagasaki, Kumamoto and Kagoshima. Same amounts of nitrogen were applied in organic and inorganic fertilizers in each field. In each site, 3 replication plots were organized in randomized block design with zero-nitrogen application plots. N2O gas fluxes were measured every one week or more during cultivation seasons. We also measured several soil physical and chemical parameters of inorganic nitrogen species, soil moisture contents or WFPS (Water Filled Pore Space), soil temperatures, bulk densities etc. Gas fluxes ware measured by automated Shimadzu GC-2014 ECD gas chromatograph. Soil moistures were measured by Camplel's Hydrosense in each site. Vegetation of conducting fields were cabbage in 7 fields, wheat in 1, pear orchard and onion in 1. Microorganisms' abundance was also considered to clarify N2O emission processes by the PCR-DGGE method.

Cracking the Stoping Paradigm: Field and Modeling Constraints From the Sierra Nevada Batholith

NASA Astrophysics Data System (ADS)

Pignotta, G. S.; Paterson, S. R.; Okaya, D.

2001-12-01

The significance of stoping during pluton emplacement remains a controversial issue. This mechanism has fallen out of favor recently largely due to the apparent lack of stoped blocks preserved in plutons. Our field studies in plutons in a variety of tectonic settings clearly show evidence of stoping. This is not surprising since stoping should be favored when large thermal gradients exist at magma-host rock boundaries. Preservation of stoped blocks is uncommon however, since the rate at which blocks sink is much greater than the rate at which magmas crystallize (Paterson and Okaya, 1999). Thus, only during final crystallization when magmatic yield strength is high, should stoped blocks be trapped. The Mitchell Peak granodiorite, Sierra Nevada is a rare example of a pluton that preserves abundant stoped blocks, with the youngest intrusive phase preserving >25% stoped blocks, and locally, near the margins >50% of exposed surface area is stoped blocks. Thus stoping is an important process here, at least during the final stages of emplacement. This area is ideal to study the mechanisms of block formation and disintegration using both field and modeling techniques, because of abundant stoped blocks, excellent exposure, and nature of host rock. The host rock is a slightly older, coarse grained, granodioritic intrusion that preserves extremely weak to no magmatic fabric, and thus can be treated as a "homogeneous and isotropic" medium for the purposes of thermal-mechanical modeling. Detailed mapping indicates that preserved stoped blocks range in size from hundreds of m's to xenocrystic feldspars, and there is abundant evidence for mechanical disintegration of blocks. Thermal-mechanical models, using detailed maps from the Mitchell Peak area, further support field observations. Rates at which thermal stresses develop and exceed host rock tensile strength are extremely rapid (hours to days) compared to onset of crystal plastic flow and/or melting. The calculated pattern of thermal stresses (i.e. high magnitudes at block corners) strongly supports rapid mechanical breakdown of stoped blocks. We suggest that rapid disintegration coupled with rapid rates of sinking of blocks explains the lack of observable blocks in plutons, and is an effective way to contaminate magmas thermally, mechanically and chemically. Furthermore, lack of observable stoped blocks in plutons should not be used as evidence that stoping did not occur.

Complete multipactor suppression in an X-band dielectric-loaded accelerating structure

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

Jing, C.; Gold, S. H.; Fischer, Richard

2016-05-09

Multipactor is a major issue limiting the gradient of rf-driven Dielectric-Loaded Accelerating (DLA) structures. Theoretical models have predicted that an axial magnetic field applied to DLA structures may completely block the multipactor discharge. However, previous attempts to demonstrate this magnetic field effect in an X-band traveling-wave DLA structure were inconclusive, due to the axial variation of the applied magnetic field, and showed only partial suppression of the multipactor loading [Jing et al., Appl. Phys. Lett. 103, 213503 (2013)]. The present experiment has been performed under improved conditions with a uniform axial magnetic field extending along the length of an X-bandmore » standing-wave DLA structure. Multipactor loading began to be continuously reduced starting from 3.5 kG applied magnetic field and was completely suppressed at 8 kG. Dependence of multipactor suppression on the rf gradient inside the DLA structure was also measured.« less

Biased Feedback in Spatial Recall Yields a Violation of Delta Rule Learning

PubMed Central

Lipinski, John; Spencer, John P.; Samuelson, Larissa K.

2010-01-01

This study investigates whether inductive processes influencing spatial memory performance generalize to supervised learning scenarios with differential feedback. After providing a location memory response in a spatial recall task, participants received visual feedback showing the target location. In critical blocks, feedback was systematically biased either 4° towards the vertical axis (Towards condition) or 4° further away from the vertical axis (Away condition). Results showed that the weaker teaching signal (i.e., a smaller difference between the remembered location and the feedback location) in the Away condition produced a stronger experience-dependent change over blocks than in the Towards condition. This violates delta rule learning. Subsequent simulations of the Dynamic Field Theory of spatial cognition provide a theoretically unified account of these results. PMID:20702881

Biased feedback in spatial recall yields a violation of delta rule learning.

PubMed

Lipinski, John; Spencer, John P; Samuelson, Larissa K

2010-08-01

This study investigates whether inductive processes influencing spatial memory performance generalize to supervised learning scenarios with differential feedback. After providing a location memory response in a spatial recall task, participants received visual feedback showing the target location. In critical blocks, feedback was systematically biased either 4 degrees toward the vertical axis (toward condition) or 4 degrees farther away from the vertical axis (away condition). Results showed that the weaker teaching signal (i.e., a smaller difference between the remembered location and the feedback location) produced a stronger experience-dependent change over blocks in the away condition than in the toward condition. This violates delta rule learning. Subsequent simulations of the dynamic field theory of spatial cognition provide a theoretically unified account of these results.

Field Emission Cold Cathode Devices Based on Eutectic Systems

DTIC Science & Technology

1981-07-01

8217RADC-TR-811-170 ’,Final Technical Report July 1981 FIELD EMISSION COLD CATHODE DEVICES BASED ON EUTECTIC SYSTEMS Fulmer Research Institute Ltd...and identify by block numrber) Field Emission Eutectic Systems Cold Cathode Rod Eutectics Electron Emitter Array Directionally Solidified Eutectics...Identify by block number) A survey has been made of the performance as field emission cold cathodes of selected refractory materials fabricated as

Significant role of structural fractures in Ren-Qiu buried-block oil field, eastern China

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

Fei, Q.; Xie-Pei, W.

1983-03-01

Ren-qui oil field is in a buried block of Sinian (upper Proterozoic) rocks located in the Ji-zhong depression of the western Bohai Bay basin in eastern China. The main reservoir consists of Sinian dolomite rocks. It is a fault block with a large growth fault on the west side which trends north-northeast with throws of up to 1 km (0.6 mi) or more. The source rocks for the oil are Paleogene age and overlie the Sinian dolomite rocks. The structural fractures are the main factor forming the reservoir of the buried-block oil field. Three structural lines, trending northeast, north-northeast, andmore » northwest, form the regional netted fracture system. The north-northeast growth fault controlled the structural development of the buried block. The block was raised and eroded before the Tertiary sediments were deposited. In the Eocene Epoch, the Ji-zhong depression subsided, but the deposition, faulting, and related uplift of the block happened synchronously as the block was gradually submerged. At the same time, several horizontal and vertical karst zones were formed by the karst water along the netted structural fractures. The Eocene oil source rocks lapped onto the block and so the buried block, with many developed karst fractures, was surrounded by a great thickness of source rocks. As the growth fault developed, the height of the block was increased from 400 m (1300 ft) before the Oligocene to 1300 m (4250 ft) after. As the petroleum was generated, it migrated immediately into the karst fractures of the buried block along the growth fault. The karst-fractured block reservoir has an 800-m (2600-ft) high oil-bearing closure and good connections developed between the karst fractures.« less

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

Yu, Yao; Chen, Josephine; Leary, Celeste I.

Radiation of the low neck can be accomplished using split-field intensity-modulated radiation therapy (sf-IMRT) or extended-field intensity-modulated radiation therapy (ef-IMRT). We evaluated the effect of these treatment choices on target coverage and thyroid and larynx doses. Using data from 14 patients with cancers of the oropharynx, we compared the following 3 strategies for radiating the low neck: (1) extended-field IMRT, (2) traditional split-field IMRT with an initial cord-junction block to 40 Gy, followed by a full-cord block to 50 Gy, and (3) split-field IMRT with a full-cord block to 50 Gy. Patients were planned using each of these 3 techniques.more » To facilitate comparison, extended-field plans were normalized to deliver 50 Gy to 95% of the neck volume. Target coverage was assessed using the dose to 95% of the neck volume (D{sub 95}). Mean thyroid and larynx doses were computed. Extended-field IMRT was used as the reference arm; the mean larynx dose was 25.7 ± 7.4 Gy, and the mean thyroid dose was 28.6 ± 2.4 Gy. Split-field IMRT with 2-step blocking reduced laryngeal dose (mean larynx dose 15.2 ± 5.1 Gy) at the cost of a moderate reduction in target coverage (D{sub 95} 41.4 ± 14 Gy) and much higher thyroid dose (mean thyroid dose 44.7 ± 3.7 Gy). Split-field IMRT with initial full-cord block resulted in greater laryngeal sparing (mean larynx dose 14.2 ± 5.1 Gy) and only a moderately higher thyroid dose (mean thyroid dose 31 ± 8 Gy) but resulted in a significant reduction in target coverage (D{sub 95} 34.4 ± 15 Gy). Extended-field IMRT comprehensively covers the low neck and achieves acceptable thyroid and laryngeal sparing. Split-field IMRT with a full-cord block reduces laryngeal doses to less than 20 Gy and spares the thyroid, at the cost of substantially reduced coverage of the low neck. Traditional 2-step split-field IMRT similarly reduces the laryngeal dose but also reduces low-neck coverage and delivers very high doses to the thyroid.« less

Right hemisphere performance and competence in processing mental images, in a case of partial interhemispheric disconnection.

PubMed

Blanc-Garin, J; Faure, S; Sabio, P

1993-05-01

The objective of this study was to analyze dynamic aspects of right hemisphere implementation in processing visual images. Two tachistoscopic, divided visual field experiments were carried out on a partial split-brain patient with no damage to the right hemisphere. In the first experiment, image generation performance for letters presented in the right visual field (/left hemisphere) was undeniably optimal. In the left visual field (/right hemisphere), performance was no better than chance level at first, but then improved dramatically across stimulation blocks, in each of five successive sessions. This was interpreted as revealing the progressive spontaneous activation of the right hemisphere's competence not shown initially. The aim of the second experiment was to determine some conditions under which this pattern was obtained. The experimental design contrasted stimuli (words and pictures) and representational activity (phonologic and visuo-imaged processing). The right visual field (/left hemisphere: LH) elicited higher performance than the left visual field (/right hemisphere, RH) in the three situations where verbal activity was required. No superiority could be found when visual images were to be generated from pictures: parallel and weak improvement of both hemispheres was observed across sessions. Two other patterns were obtained: improvement in RH performance (although LH performance remained superior) and an unexpectedly large decrease in RH performance. These data are discussed in terms of RH cognitive competence and hemisphere implementation.

Observation of backscattering-immune chiral electromagnetic modes without time reversal breaking.

PubMed

Chen, Wen-Jie; Hang, Zhi Hong; Dong, Jian-Wen; Xiao, Xiao; Wang, He-Zhou; Chan, C T

2011-07-08

A strategy is proposed to realize robust transport in a time reversal invariant photonic system. Using numerical simulation and a microwave experiment, we demonstrate that a chiral guided mode in the channel of a three-dimensional dielectric layer-by-layer photonic crystal is immune to the scattering of a square patch of metal or dielectric inserted to block the channel. The chirality based robust transport can be realized in nonmagnetic dielectric materials without any external field.

Eye Movements Reveal Fast, Voice-Specific Priming

PubMed Central

Papesh, Megan H.; Goldinger, Stephen D.; Hout, Michael C.

2015-01-01

In spoken word perception, voice specificity effects are well-documented: When people hear repeated words in some task, performance is generally better when repeated items are presented in their originally heard voices, relative to changed voices. A key theoretical question about voice specificity effects concerns their time-course: Some studies suggest that episodic traces exert their influence late in lexical processing (the time-course hypothesis; McLennan & Luce, 2005), whereas others suggest that episodic traces influence immediate, online processing. We report two eye-tracking studies investigating the time-course of voice-specific priming within and across cognitive tasks. In Experiment 1, participants performed modified lexical decision or semantic classification to words spoken by four speakers. The tasks required participants to click a red “×” or a blue “+” located randomly within separate visual half-fields, necessitating trial-by-trial visual search with consistent half-field response mapping. After a break, participants completed a second block with new and repeated items, half spoken in changed voices. Voice effects were robust very early, appearing in saccade initiation times. Experiment 2 replicated this pattern while changing tasks across blocks, ruling out a response priming account. In the General Discussion, we address the time-course hypothesis, focusing on the challenge it presents for empirical disconfirmation, and highlighting the broad importance of indexical effects, beyond studies of priming. PMID:26726911

Method and system for progressive mesh storage and reconstruction using wavelet-encoded height fields

NASA Technical Reports Server (NTRS)

Baxes, Gregory A. (Inventor); Linger, Timothy C. (Inventor)

2011-01-01

Systems and methods are provided for progressive mesh storage and reconstruction using wavelet-encoded height fields. A method for progressive mesh storage includes reading raster height field data, and processing the raster height field data with a discrete wavelet transform to generate wavelet-encoded height fields. In another embodiment, a method for progressive mesh storage includes reading texture map data, and processing the texture map data with a discrete wavelet transform to generate wavelet-encoded texture map fields. A method for reconstructing a progressive mesh from wavelet-encoded height field data includes determining terrain blocks, and a level of detail required for each terrain block, based upon a viewpoint. Triangle strip constructs are generated from vertices of the terrain blocks, and an image is rendered utilizing the triangle strip constructs. Software products that implement these methods are provided.

Method and system for progressive mesh storage and reconstruction using wavelet-encoded height fields

NASA Technical Reports Server (NTRS)

Baxes, Gregory A. (Inventor)

2010-01-01

Systems and methods are provided for progressive mesh storage and reconstruction using wavelet-encoded height fields. A method for progressive mesh storage includes reading raster height field data, and processing the raster height field data with a discrete wavelet transform to generate wavelet-encoded height fields. In another embodiment, a method for progressive mesh storage includes reading texture map data, and processing the texture map data with a discrete wavelet transform to generate wavelet-encoded texture map fields. A method for reconstructing a progressive mesh from wavelet-encoded height field data includes determining terrain blocks, and a level of detail required for each terrain block, based upon a viewpoint. Triangle strip constructs are generated from vertices of the terrain blocks, and an image is rendered utilizing the triangle strip constructs. Software products that implement these methods are provided.

Short infrared laser pulses block action potentials in neurons

NASA Astrophysics Data System (ADS)

Walsh, Alex J.; Tolstykh, Gleb P.; Martens, Stacey L.; Ibey, Bennett L.; Beier, Hope T.

2017-02-01

Short infrared laser pulses have many physiological effects on cells including the ability to stimulate action potentials in neurons. Here we show that short infrared laser pulses can also reversibly block action potentials. Primary rat hippocampal neurons were transfected with the Optopatch2 plasmid, which contains both a blue-light activated channel rhodopsin (CheRiff) and a red-light fluorescent membrane voltage reporter (QuasAr2). This optogenetic platform allows robust stimulation and recording of action potential activity in neurons in a non-contact, low noise manner. For all experiments, QuasAr2 was imaged continuously on a wide-field fluorescent microscope using a Krypton laser (647 nm) as the excitation source and an EMCCD camera operating at 1000 Hz to collect emitted fluorescence. A co-aligned Argon laser (488 nm, 5 ms at 10Hz) provided activation light for CheRiff. A 200 mm fiber delivered infrared light locally to the target neuron. Reversible action potential block in neurons was observed following a short infrared laser pulse (0.26-0.96 J/cm2; 1.37-5.01 ms; 1869 nm), with the block persisting for more than 1 s with exposures greater than 0.69 J/cm2. Action potential block was sustained for 30 s with the short infrared laser pulsed at 1-7 Hz. Full recovery of neuronal activity was observed 5-30s post-infrared exposure. These results indicate that optogenetics provides a robust platform for the study of action potential block and that short infrared laser pulses can be used for non-contact, reversible action potential block.

Self-assembly behavior of pH- and thermosensitive amphiphilic triblock copolymers in solution: experimental studies and self-consistent field theory simulations.

PubMed

Cai, Chunhua; Zhang, Liangshun; Lin, Jiaping; Wang, Liquan

2008-10-09

We investigated, both experimentally and theoretically, the self-assembly behaviors of pH- and thermosensitive poly(L-glutamic acid)- b-poly(propylene oxide)-b-poly(L-glutamic acid) (PLGA-b-PPO-b-PLGA) triblock copolymers in aqueous solution by means of transmission electron microscopy (TEM), scanning electron microscopy (SEM), dynamic light scattering (DLS), circular dichroism (CD), and self-consistent field theory (SCFT) simulations. Vesicles were observed when the hydrophilic PLGA block length is shorter or the pH value of solution is lower. The vesicles were found to transform to spherical micelles when the PLGA block length increases or its conformation changes from helix to coil with increasing the pH value. In addition, increasing temperature gives rise to a decrease in the size of aggregates, which is related to the dehydration of the PPO segments at higher temperatures. The SCFT simulation results show that the vesicles transform to the spherical micelles with increasing the fraction or statistical length of A block in model ABA triblock copolymer, which corresponds to the increase in the PLGA length or its conformation change from helix to coil in experiments, respectively. The SCFT calculations also provide chain distribution information in the aggregates. On the basis of both experimental and SCFT results, the mechanism of the structure change of the PLGA- b-PPO- b-PLGA aggregates was proposed.

Molecular based magnets comprising vanadium tetracyanoethylene complexes for shielding electromagnetic fields

DOEpatents

Epstein, A.J.; Morin, B.G.

1998-10-13

The invention presents a vanadium tetracyanoethylene solvent complex for electromagnetic field shielding, and a method for blocking low frequency and magnetic fields using these vanadium tetracyanoethylene compositions. The compositions of the invention can be produced at ambient temperature and are light weight, low density and flexible. The materials of the present invention are useful as magnetic shields to block low frequency fields and static fields, and for use in cores in transformers and motors. 21 figs.

Molecular based magnets comprising vanadium tetracyanoethylene complexes for shielding electromagnetic fields

DOEpatents

Epstein, Arthur J.; Morin, Brian G.

1998-01-01

The invention presents a vanadium tetracyanoethylene solvent complex for electromagnetic field shielding, and a method for blocking low frequency and magnetic fields using these vanadium tetracyanoethylene compositions. The compositions of the invention can be produced at ambient temperature and are light weight, low density and flexible. The materials of the present invention are useful as magnetic shields to block low frequency fields and static fields, and for use in cores in transformers and motors.

Photovoltaic module reliability improvement through application testing and failure analysis

NASA Technical Reports Server (NTRS)

Dumas, L. N.; Shumka, A.

1982-01-01

During the first four years of the U.S. Department of Energy (DOE) National Photovoltatic Program, the Jet Propulsion Laboratory Low-Cost Solar Array (LSA) Project purchased about 400 kW of photovoltaic modules for test and experiments. In order to identify, report, and analyze test and operational problems with the Block Procurement modules, a problem/failure reporting and analysis system was implemented by the LSA Project with the main purpose of providing manufacturers with feedback from test and field experience needed for the improvement of product performance and reliability. A description of the more significant types of failures is presented, taking into account interconnects, cracked cells, dielectric breakdown, delamination, and corrosion. Current design practices and reliability evaluations are also discussed. The conducted evaluation indicates that current module designs incorporate damage-resistant and fault-tolerant features which address field failure mechanisms observed to date.

BioBlocks: Programming Protocols in Biology Made Easier.

PubMed

Gupta, Vishal; Irimia, Jesús; Pau, Iván; Rodríguez-Patón, Alfonso

2017-07-21

The methods to execute biological experiments are evolving. Affordable fluid handling robots and on-demand biology enterprises are making automating entire experiments a reality. Automation offers the benefit of high-throughput experimentation, rapid prototyping, and improved reproducibility of results. However, learning to automate and codify experiments is a difficult task as it requires programming expertise. Here, we present a web-based visual development environment called BioBlocks for describing experimental protocols in biology. It is based on Google's Blockly and Scratch, and requires little or no experience in computer programming to automate the execution of experiments. The experiments can be specified, saved, modified, and shared between multiple users in an easy manner. BioBlocks is open-source and can be customized to execute protocols on local robotic platforms or remotely, that is, in the cloud. It aims to serve as a de facto open standard for programming protocols in Biology.

Background ELF magnetic fields in incubators: a factor of importance in cell culture work.

PubMed

Mild, Kjell Hansson; Wilén, Jonna; Mattsson, Mats-Olof; Simko, Myrtill

2009-07-01

Extremely low frequency (ELF) magnetic fields in cell culture incubators have been measured. Values of the order of tens of muT were found which is in sharp contrast to the values found in our normal environment (0.05-0.1microT). There are numerous examples of biological effects found after exposure to MF at these levels, such as changes in gene expression, blocked cell differentiation, inhibition of the effect of tamoxifen, effects on chick embryo development, etc. We therefore recommend that people working with cell culture incubators check for the background magnetic field and take this into account in performing their experiments, since this could be an unrecognised factor of importance contributing to the variability in the results from work with cell cultures.

CALUTRON

DOEpatents

Lofgren, E.J.

1960-01-19

An ion source suitable for use with isotope separators of the calutron class is described in which ion bombardment of source structural members is minimized to lessen deterioration. A hollow conducting block defines an arc chamber which has an ion exit opening in the form of a slot in one wall of the block. A charged electrode spaced from the opening applies an electrical field for withdrawing ions from within the block. To establish a field configuration whereby the impingement of ions on the walls of the block is reduced, the wall edges which define the slot opening are bevelled to converge in the direction of efflux of the ions.

Electric-Field-Induced Alignment of Block Copolymer/Nanoparticle Blends

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

Liedel, Clemens; Schindler, Kerstin; Pavan, Mariela J.

External electric fi elds readily align birefringent block-copolymer mesophases. In this study the effect of gold nanoparticles on the electric-fi eld-induced alignment of a lamellae-forming polystyrene- block -poly(2-vinylpyridine) copolymer is assessed. Nanoparticles are homogeneously dispersed in the styrenic phase and promote the quantitative alignment of lamellar domains by substantially lowering the critical field strength above which alignment proceeds. The results suggest that the electric-fi eldassisted alignment of nanostructured block copolymer/nanoparticle composites may offer a simple way to greatly mitigate structural and orientational defects of such fi lms under benign experimental conditions.

Effects of radiation damping for biomolecular NMR experiments in solution: a hemisphere concept for water suppression

PubMed Central

Ishima, Rieko

2016-01-01

Abundant solvent nuclear spins, such as water protons in aqueous solution, cause radiation damping in NMR experiments. It is important to know how the effect of radiation damping appears in high-resolution protein NMR because macromolecular studies always require very high magnetic field strengths with a highly sensitive NMR probe that can easily cause radiation damping. Here, we show the behavior of water magnetization after a pulsed-field gradient (PFG) using nutation experiments at 900 MHz with a cryogenic probe: when water magnetization is located in the upper hemisphere (having +Z component, parallel to the external magnetic field), dephasing of the magnetization by a PFG effectively suppresses residual water magnetization in the transverse plane. In contrast, when magnetization is located in the lower hemisphere (having −Z component), the small residual transverse component remaining after a PFG is still sufficient to induce radiation damping. Based on this observation, we designed 1H-15N HSQC experiments in which water magnetization is maintained in the upper hemisphere, but not necessarily along Z, and compared them with the conventional experiments, in which water magnetization is inverted during the t1 period. The result demonstrates moderate gain of signal-to-noise ratio, 0–28%. Designing the experiments such that water magnetization is maintained in the upper hemisphere allows shorter pulses to be used compared to the complete water flip-back and, thereby, is useful as a building block of protein NMR pulse programs in solution. PMID:27524944

Report of Block Field Experience at Jefferson County Department of Health Bureau of Nutrition, Birmingham, Alabama.

DTIC Science & Technology

1985-01-01

Despite the recent economic growth of Jefferson County, poverty * still abounds. In 1980, 12% of the families lived below the poverty level and some...residents with the charge for services being based on a sliding fee scale. Those at or below 150% of poverty level are charged only a minimum fee. F...be at risk? 1. Poor dietary calcium intake - average intake for American women is less than 500 grams per day. 2. Smoking - nicotine hurries the

Semiclassical Virasoro blocks from AdS 3 gravity

DOE PAGES

Hijano, Eliot; Kraus, Per; Perlmutter, Eric; ...

2015-12-14

We present a unified framework for the holographic computation of Virasoro conformal blocks at large central charge. In particular, we provide bulk constructions that correctly reproduce all semiclassical Virasoro blocks that are known explicitly from conformal field theory computations. The results revolve around the use of geodesic Witten diagrams, recently introduced in [1], evaluated in locally AdS 3 geometries generated by backreaction of heavy operators. We also provide an alternative computation of the heavy-light semiclassical block — in which two external operators become parametrically heavy — as a certain scattering process involving higher spin gauge fields in AdS 3; thismore » approach highlights the chiral nature of Virasoro blocks. Finally, these techniques may be systematically extended to compute corrections to these blocks and to interpolate amongst the different semiclassical regimes.« less

Mode jumping of split-ring resonator metamaterials controlled by high-permittivity BST and incident electric fields

PubMed Central

Fu, Xiaojian; Zeng, Xinxi; Cui, Tie Jun; Lan, Chuwen; Guo, Yunsheng; Zhang, Hao Chi; Zhang, Qian

2016-01-01

We investigate the resonant modes of split-ring resonator (SRR) metamaterials that contain high-permittivity BST block numerically and experimentally. We observe interesting mode-jumping phenomena from the BST-included SRR absorber structure as the excitation wave is incident perpendicularly to the SRR plane. Specifically, when the electric field is parallel to the SRR gap, the BST block in the gap will induce a mode jumping from the LC resonance to plasmonic resonance (horizontal electric-dipole mode), because the displacement current excited by the Mie resonance in the dielectric block acts as a current channel in the gap. When the electric field is perpendicular to the gap side, the plasmonic resonance mode (vertical electric-dipole mode) in SRR changes to two joint modes contributed simultaneously by the back layer, SRR and BST block, as a result of connected back layer and SRR layer by the displacement current in the BST dielectric block. Based on the mode jumping effect as well as temperature and electric-field dependent dielectric constant, the BST-included SRR metamaterials may have great potentials for the applications in electromagnetic switches and widely tunable metamaterial devices. PMID:27502844

Role of the electric field in selective ion filtration in nanostructures.

PubMed

Park, Yong; Kim, Sueon; Jang, In Hyuk; Nam, Young Suk; Hong, Hiki; Choi, Dukhyun; Lee, Won Gu

2016-02-21

Nafion has received great attention as a proton conductor that can block negative ions. Here, we report the effect of a Nafion coating on an anodic aluminium oxide (AAO) nanoporous membrane on its function of ion rejection and filtering depending on the electric field. In our experiments, Nafion, once coated, was used to repel the negative ions (anions) from the coated surface, and then selectively allowed positive ions (cations) to pass through the nanopores in the presence of an electric field. To demonstrate the proof-of-concept validation, we coated Nafion solution onto the surface of AAO membranes with 20 nm nanopores average diameter at different solution concentration levels. Vacuum filtration methods for Nafion coating were vertically applied to the plane of an AAO membrane. An electric field was then applied to the upper surface of the Nafion-coated AAO membrane to investigate if ion rejection and filtering was affected by the presence of the electric field. Both anions and cations could pass through the AAO nanopores without an electric field applied. However, only cations could well pass through the AAO nanopores under an electric field, thus effectively blocking anions from passing through the nanopores. This result shows that ion filtration of electrons has been selectively performed while the system also works as a vital catalyst in reactivating Nafion via electrolysis. A saturated viscosity ratio of Nafion solution for the coating was also determined. We believe that this approach is potentially beneficial for better understanding the fundamentals of selective ion filtration in nanostructures and for promoting the use of nanostructures in potential applications such as ion-based water purification and desalination system at the nanoscale in a massively electrically integrated format.

Land Cover Change in the Boston Mountains, 1973-2000

USGS Publications Warehouse

Karstensen, Krista A.

2009-01-01

The U.S. Geological Survey (USGS) Land Cover Trends project is focused on understanding the rates, trends, causes, and consequences of contemporary U.S. land-cover change. The objectives of the study are to: (1) to develop a comprehensive methodology for using sampling and change analysis techniques and Landsat Multispectral Scanner (MSS), Thematic Mapper (TM), and Enhanced Thematic Mapper Plus (ETM+) data to measure regional land-cover change across the United States; (2) to characterize the types, rates, and temporal variability of change for a 30-year period; (3) to document regional driving forces and consequences of change; and (4) to prepare a national synthesis of land-cover change (Loveland and others, 1999). The 1999 Environmental Protection Agency (EPA) Level III ecoregions derived from Omernik (1987) provide the geographic framework for the geospatial data collected between 1973 and 2000. The 27-year study period was divided into five temporal periods: 1973-1980, 1980-1986, 1986-1992, 1992-2000, and 1973-2000, and the data are evaluated using a modified Anderson Land Use Land Cover Classification System (Anderson and others, 1976) for image interpretation. The rates of land-cover change are estimated using a stratified, random sampling of 10-kilometer (km) by 10-km blocks allocated within each ecoregion. For each sample block, satellite images are used to interpret land-cover change for the five time periods previously mentioned. Additionally, historic aerial photographs from similar time frames and other ancillary data, such as census statistics and published literature, are used. The sample block data are then incorporated into statistical analyses to generate an overall change matrix for the ecoregion. Field data of the sample blocks include direct measurements of land cover, particularly ground-survey data collected for training and validation of image classifications (Loveland and others, 2002). The field experience allows for additional observations of the character and condition of the landscape, assistance in sample block interpretation, ground truthing of Landsat imagery, and determination of the driving forces of change identified in an ecoregion.

Muon spin relaxation study of the layered magnetoelectric FeTe2O5Br with spin amplitude modulated magnetic structure

NASA Astrophysics Data System (ADS)

Zorko, A.; Pregelj, M.; Berger, H.; Arčon, D.

2010-05-01

Local-probe weak-transverse-field and zero-field μSR measurements have been employed to investigate magnetic ordering in the new magnetoelectric compound FeTe2O5Br. Below the Néel transition temperature TN=10.6 K a static local magnetic field starts to develop at the μ+ sites. Fast μ+ polarization decay below TN speaks in favor of a broad distribution of internal magnetic fields, in agreement with the incommensurate magnetic structure suggested by neutron diffraction experiments. Above TN the presence of short-range order is detected as high as at 2TN, which suggests only weak interlayer magnetic coupling. On the other hand, strong Fe3+ spin fluctuations likely reflect geometrically frustrated structure of [Fe4O16]20- spin clusters, which are the main building blocks of the layered FeTe2O5Br structure.

Gas block mechanism for water removal in fuel cells

DOEpatents

Issacci, Farrokh; Rehg, Timothy J.

2004-02-03

The present invention is directed to apparatus and method for cathode-side disposal of water in an electrochemical fuel cell. There is a cathode plate. Within a surface of the plate is a flow field comprised of interdigitated channels. During operation of the fuel cell, cathode gas flows by convection through a gas diffusion layer above the flow field. Positioned at points adjacent to the flow field are one or more porous gas block mediums that have pores sized such that water is sipped off to the outside of the flow field by capillary flow and cathode gas is blocked from flowing through the medium. On the other surface of the plate is a channel in fluid communication with each porous gas block mediums. The method for water disposal in a fuel cell comprises installing the cathode plate assemblies at the cathode sides of the stack of fuel cells and manifolding the single water channel of each of the cathode plate assemblies to the coolant flow that feeds coolant plates in the stack.

Spatial distribution pattern of termite in Endau Rompin Plantation

NASA Astrophysics Data System (ADS)

Jalaludin, Nur-Atiqah; Rahim, Faszly

2015-09-01

We censused 18 field blocks approximately 190 ha with total of 28,604 palms in a grid of 2×4 palms from July 2011 to March 2013. The field blocks comprise of rows of palm trees, harvesting paths, field drains and stacking rows with maximum of 30 palms per row, planted about 9 m apart, alternately in maximum of 80 rows. SADIE analysis generating index of aggregation, Ia, local clustering value, Vi and local gap value, Vj is adopted to estimate spatial pattern. The patterns were then presented in contour map using Surfer 12 software. The patterns produced associated with factors i.e. habitat disturbance, habitat fragmentation and resources affecting nesting and foraging activities. Result shows that field blocks with great habitat disturbance recorded highest dead palms and termites hits. Blocks located far from the main access road recorded less than 2% palms with termite hits. This research may provide ecological data on termite spatial pattern in oil palm ecosystem.

Processing of form stimuli presented unilaterally in humans, chimpanzees (Pan troglodytes), and monkeys (Macaca mulatta)

NASA Technical Reports Server (NTRS)

Hopkins, William D.; Washburn, David A.; Rumbaugh, Duane M.

1990-01-01

Visual forms were unilaterally presented using a video-task paradigm to ten humans, chimpanzees, and two rhesus monkeys to determine whether hemispheric advantages existed in the processing of these stimuli. Both accuracy and reaction time served as dependent measures. For the chimpanzees, a significant right hemisphere advantage was found within the first three test sessions. The humans and monkeys failed to show a hemispheric advantage as determined by accuracy scores. Analysis of reaction time data revealed a significant left hemisphere advantage for the monkeys. A visual half-field x block interaction was found for the chimpanzees, with a significant left visual field advantage in block two, whereas a right visual field advantage was found in block four. In the human subjects, a left visual field advantage was found in block three when they used their right hands to respond. The results are discussed in relation to recent reports of hemispheric advantages for nonhuman primates.

How can I tell where the valid data begins and ends in L1B2 products?

Atmospheric Science Data Center

2014-12-08

... of metadata fields to assist you in determining which data are relevant. All L1B2 files begin with block number 1, even though block ... and "End block" in order to locate valid data. Note : The missing underscore in End block is real. The L1B2 per-block metadata also ...

Paving block study : final report.

DOT National Transportation Integrated Search

1971-10-01

The Louisiana Department of Highways has conducted field tests with an experimental revetment consisting of cellular concrete revetment blocks used in conjunction with plastic filter cloth and/or vegetation such as grass or vines. The precast blocks ...

List blocking and longer retention intervals reveal an influence of gist processing for lexically ambiguous critical lures

PubMed Central

McNabb, Jaimie; Hutchison, Keith A.

2016-01-01

In two experiments, we examined veridical and false memory for lists of associates from two meanings (e.g., stumble, trip, harvest, pumpkin, etc.) that converged upon a single, lexically ambiguous critical lure (e.g., fall), in order to compare the activation-monitoring and fuzzy-trace false memory accounts. In Experiment 1, we presented study lists that were blocked or alternated by meaning (within subjects), followed by a free recall test completed immediately or after a 2.5-min delay. Correct recall was greater for blocked than for alternated lists. Critical-lure false recall was greater for blocked lists on an immediate test, whereas both list types produced equivalent false recall on a delayed test. In Experiment 2, lists blocked and alternated by meaning were presented via a between-subjects design, in order to eliminate possible list-type carryover effects. Correct recall replicated the result from Experiment 1; however, blocking lists increased false recall on delayed, but not on immediate, tests. Across the experiments, clustering correct recall by meaning increased across the delay selectively for the alternated lists. Our results suggest that thematic (i.e., gist) processes are influential for false recall, especially following a delay, a pattern consistent with fuzzy-trace theory. PMID:26105976

Rotating plasma structures in the cross-field discharge of Hall thrusters

NASA Astrophysics Data System (ADS)

Mazouffre, Stephane; Grimaud, Lou; Tsikata, Sedina; Matyash, Konstantin

2016-09-01

Rotating plasma structures, also termed rotating spokes, are observed in various types of low-pressure discharges with crossed electric and magnetic field configurations, such as Penning sources, magnetron discharges, negative ion sources and Hall thrusters. Such structures correspond to large-scale high-density plasma blocks that rotate in the E×B drift direction with a typical frequency on the order of a few kHz. Although such structures have been extensively studied in many communities, the mechanism at their origin and their role in electron transport across the magnetic field remain unknown. Here, we will present insights into the nature of spokes, gained from a combination of experiments and advanced particle-in-cell numerical simulations that aim at better understanding the physics and the impact of rotating plasma structures in the ExB discharge of the Hall thruster. As rotating spokes appear in the ionization region of such thrusters, and are therefore difficult to probe with diagnostics, experiments have been performed with a wall-less Hall thruster. In this configuration, the entire plasma discharge is pushed outside the dielectric cavity, through which the gas is injected, using the combination of specific magnetic field topology with appropriate anode geometry.

Diffusion of hydrogen interstitials in the near-surface region of Pd(111) under the influence of surface coverage and external static electric fields

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

Blanco-Rey, M.; Donostia International Physics Center; Tremblay, J. C.

2015-04-21

Past scanning tunneling microscopy (STM) experiments of H manipulation on Pd(111), at low temperature, have shown that it is possible to induce diffusion of surface species as well as of those deeply buried under the surface. Several questions remain open regarding the role of subsurface site occupancies. In the present work, the interaction potential of H atoms with Pd(111) under various H coverage conditions is determined by means of density functional theory calculations in order to provide an answer to two of these questions: (i) whether subsurface sites are the final locations for the H impurities that attempt to emergemore » from bulk regions, and (ii) whether penetration of the surface is a competing route of on-surface diffusion during depletion of surface H on densely covered Pd(111). We find that a high H coverage has the effect of blocking resurfacing of H atoms travelling from below, which would otherwise reach the surface fcc sites, but it hardly alters deeper diffusion energy barriers. Penetration is unlikely and restricted to high occupancies of hcp hollows. In agreement with experiments, the Pd lattice expands vertically as a consequence of H atoms being blocked at subsurface sites, and surface H enhances this expansion. STM tip effects are included in the calculations self-consistently as an external static electric field. The main contribution to the induced surface electric dipoles originates from the Pd substrate polarisability. We find that the electric field has a non-negligible effect on the H-Pd potential in the vicinity of the topmost Pd atomic layer, yet typical STM intensities of 1-2 VÅ{sup −1} are insufficient to invert the stabilities of the surface and subsurface equilibrium sites.« less

Experimental validation of microseismic emissions from a controlled hydraulic fracture in a synthetic layered medium

NASA Astrophysics Data System (ADS)

Roundtree, Russell

A controlled hydraulic fracture experiment was performed on two medium sized (11" x 11" x 15") synthetic layered blocks of low permeability, low porosity Lyons sandstone sandwiched between cement. The purpose of the research was to better understand and characterize the fracture evolution as the fracture tip impinged upon the layer boundaries between the well bonded layers. It is also one of the first documented uses of passive microseismic used in a laboratory environment to characterize hydraulic fracturing. A relatively low viscosity fluid of 1000 centipoise, compared to properly scaled previous work (Casas 2005, and Athavale 2007), was pumped at a constant rate of 10 mL/minute through a steel cased hole landed and isolated in the sandstone layer. Efforts were made to contain the hydraulic fracture within the confines of the rock specimen to retain the created hydraulic fracture geometry. Two identical samples and treatment schedules were created and differed only in the monitoring system used to characterize the microseismic activity during the fracture treatment. The first block had eight embedded P-wave transducers placed in the sandstone layer to record the passive microseismic emissions and localize the location and time of the acoustic event. The second block had six compressional wave transducers and twelve shear wave transducers embedded in the sandstone layer of the block. The intention was to record and process the seismic data using conventional P-wave to S-wave difference timing techniques well known in industry. While this goal ultimately not possible due to the geometry of the receiver placements and the limitations of the Vallene acquisition processing software, the data received and the events localized from the 18 transducer test were of much higher numbers and quality than on the eight transducer test. This experiment proved conclusively that passive seismic emission recording can yield positive results in the laboratory. Just as in the field, this provides one of the best far field (away from the well bore) measurements to assess hydraulic fracture behavior. It also provides a calibration tool to extend laboratory results to field scale endeavors. The identification of strong microseismic activity at stress states far below fracture initiation confirms that rocks are critically stressed meta-stable materials and that microseismicity is caused by stress changes, not fractures directly. Advancements are necessary to fully exploit the potential of the microseismic method in laboratory sized samples. Both processing and visualization enhancements are necessary to realize the full benefits of this promising technology in the laboratory environment.

Numbers of center points appropriate to blocked response surface experiments

NASA Technical Reports Server (NTRS)

Holms, A. G.

1979-01-01

Tables are given for the numbers of center points to be used with blocked sequential designs of composite response surface experiments as used in empirical optimum seeking. The star point radii for exact orthogonal blocking is presented. The center point options varied from a lower limit of one to an upper limit equal to the numbers proposed by Box and Hunter for approximate rotatability and uniform variance, and exact orthogonal blocking. Some operating characteristics of the proposed options are described.

Spatial separation of target and competitor cues enhances blocking of human causality judgements.

PubMed

Glautier, Steven

2002-04-01

Three experiments were carried out. Each required subjects to make judgements about the causal status of cues following a two-stage blocking procedure. In Stage 1 a competitor cue was consistently paired with an outcome, and in Stage 2 the competitor continued to be paired with the outcome but was accompanied by a target cue. It was predicted that causal judgements for the target would be reduced by the presence of the competitor. In Experiments 1 and 2 the blocking procedure was implemented as a computer simulation of a card game during which subjects had to learn which cards produced the best payouts. The cues that subjects used to make their judgement were colours and symbols that appeared on the backs of the cards. When the target and competitor cues appeared on the same card blocking effects did not emerge, but when they appeared as part of different cards blocking effects were found. Thus, spatial separation of target and competitor cues appeared to facilitate blocking. Experiment 3 replicated the blocking result using spatially separated target and competitor cues.

A stereoscopic look into the bulk

DOE PAGES

Czech, Bartlomiej; Lamprou, Lampros; McCandlish, Samuel; ...

2016-07-26

Here, we present the foundation for a holographic dictionary with depth perception. The dictionary consists of natural CFT operators whose duals are simple, diffeomorphism-invariant bulk operators. The CFT operators of interest are the “OPE blocks,” contributions to the OPE from a single conformal family. In holographic theories, we show that the OPE blocks are dual at leading order in 1/N to integrals of effective bulk fields along geodesics or homogeneous minimal surfaces in anti-de Sitter space. One widely studied example of an OPE block is the modular Hamiltonian, which is dual to the fluctuation in the area of a minimalmore » surface. Thus, our operators pave the way for generalizing the Ryu-Takayanagi relation to other bulk fields. Although the OPE blocks are non-local operators in the CFT, they admit a simple geometric description as fields in kinematic space — the space of pairs of CFT points. We develop the tools for constructing local bulk operators in terms of these non-local objects. The OPE blocks also allow for conceptually clean and technically simple derivations of many results known in the literature, including linearized Einstein’s equations and the relation between conformal blocks and geodesic Witten diagrams.« less

Toward single electron resolution phonon mediated ionization detectors

NASA Astrophysics Data System (ADS)

Mirabolfathi, Nader; Harris, H. Rusty; Mahapatra, Rupak; Sundqvist, Kyle; Jastram, Andrew; Serfass, Bruno; Faiez, Dana; Sadoulet, Bernard

2017-05-01

Experiments seeking to detect rare event interactions such as dark matter or coherent elastic neutrino nucleus scattering are striving for large mass detectors with very low detection threshold. Using Neganov-Luke phonon amplification effect, the Cryogenic Dark Matter Search (CDMS) experiment is reaching unprecedented RMS resolutions of ∼14 eVee. CDMSlite is currently the most sensitive experiment to WIMPs of mass ∼5 GeV/c2 but is limited in achieving higher phonon gains due to an early onset of leakage current into Ge crystals. The contact interface geometry is particularly weak for blocking hole injection from the metal, and thus a new design is demonstrated that allows high voltage bias via vacuum separated electrode. With an increased bias voltage and a×2 Luke phonon gain, world best RMS resolution of sigma ∼7 eVee for 0.25 kg (d=75 mm, h=1 cm) Ge detectors was achieved. Since the leakage current is a function of the field and the phonon gain is a function of the applied voltage, appropriately robust interface blocking material combined with thicker substrate (25 mm) will reach a resolution of ∼2.8 eVee. In order to achieve better resolution of ∼ eV, we are investigating a layer of insulator between the phonon readout surface and the semiconductor crystals.

Avalanche boron fusion by laser picosecond block ignition with magnetic trapping for clean and economic reactor

DOE PAGES

Hora, H.; Korn, G.; Eliezer, S.; ...

2016-10-11

Measured highly elevated gains of proton–boron (HB11) fusion (Picciottoet al., Phys. Rev. X4, 031030 (2014)) confirmed the exceptional avalanche reaction process (Lalousiset al., Laser Part. Beams 32, 409 (2014); Horaet al., Laser Part. Beams33, 607 (2015)) for the combination of the non-thermal block ignition using ultrahigh intensity laser pulses of picoseconds duration. The ultrahigh accelerationabovemore » $$10^{20}~\\text{cm}~\\text{s}^{-2}$$ for plasma blocks was theoretically and numerically predicted since 1978 (Hora,Physics of Laser Driven Plasmas(Wiley, 1981), pp. 178 and 179) and measured (Sauerbrey, Phys. Plasmas3, 4712 (1996)) in exact agreement (Horaet al., Phys. Plasmas14, 072701 (2007)) when the dominating force was overcoming thermal processes. This is based on Maxwell’s stress tensor by the dielectric properties of plasma leading to the nonlinear (ponderomotive) force $$f_{\\text{NL}}$$ resulting in ultra-fast expanding plasma blocks by a dielectric explosion. Combining this with measured ultrahigh magnetic fields and the avalanche process opens an option for an environmentally absolute clean and economic boron fusion power reactor. Finally, this is supported also by other experiments with very high HB11 reactions under different conditions (Labauneet al., Nature Commun.4, 2506 (2013)).« less

Evaluation of Sealing Materials and Techniques for Installing Quoin and Miter Block Backing Grout

DTIC Science & Technology

2015-11-01

being used effectively in the field. The materials currently in use have low viscosities and are typically poured behind the quoin and miter blocks in...tively in the field. The materials now used have low viscosities . They are typ- ically poured behind the quoin and miter blocks in lifts. The perimeter of...colder temperatures. Low viscosity at warmer temperatures. Hilti HIT ICE Epoxy Acrylate It is primarily a cold weather product that had poor

Unraveling the Driving Forces in the Self-Assembly of Monodisperse Naphthalenediimide-Oligodimethylsiloxane Block Molecules

PubMed Central

2017-01-01

Block molecules belong to a rapidly growing research field in materials chemistry in which discrete macromolecular architectures bridge the gap between block copolymers (BCP) and liquid crystals (LCs). The merging of characteristics from both BCP and LCs is expected to result in exciting breakthroughs, such as the discovery of unexpected morphologies or significant shrinking of domain spacings in materials that possess the high definition of organic molecules and the processability of polymers. Here we report the bulk self-assembly of two families of monodisperse block molecules comprised of naphthalenediimides (NDIs) and oligodimethylsiloxanes (ODMS). These materials are characterized by waxy texture, strong long-range order, and very low mobility, typical properties of conformationally disordered crystals. Our investigation unambiguously reveals that thermodynamic immiscibility and crystallization direct the self-assembly of ODMS-based block molecules. We show that a synergy of high incompatibility between the blocks and crystallization of the NDIs causes nanophase separation, giving access to hexagonally packed columnar (Colh) and lamellar (LAM) morphologies with sub-10 nm periodicities. The domain spacings can be tuned by mixing molecules with different ODMS lengths and the same number of NDIs, introducing an additional layer of control. X-ray scattering experiments reveal macrophase separation whenever this constitutional bias is not observed. Finally, we highlight our “ingredient approach” to obtain perfect order in sub-10 nm structured materials with a simple strategy built on a crystalline “hard” moiety and an incompatible “soft” ODMS partner. Following this simple rule, our recipe can be extended to a number of systems. PMID:28380290

Chain end distribution of block copolymer in two-dimensional microphase-separated structure studied by scanning near-field optical microscopy.

PubMed

Sekine, Ryojun; Aoki, Hiroyuki; Ito, Shinzaburo

2009-10-01

The chain end distribution of a block copolymer in a two-dimensional microphase-separated structure was studied by scanning near-field optical microscopy (SNOM). In the monolayer of poly(octadecyl methacrylate)-block-poly(isobutyl methacrylate) (PODMA-b-PiBMA), the free end of the PiBMA subchain was directly observed by SNOM, and the spatial distributions of the whole block and the chain end are examined and compared with the convolution of the point spread function of the microscope and distribution function of the model structures. It was found that the chain end distribution of the block copolymer confined in two dimensions has a peak near the domain center, being concentrated in the narrower region, as compared with three-dimensional systems.

Prospecting of popcorn hybrids for resistance to fall armyworm.

PubMed

Crubelati-Mulati, N C S; Scapim, C A; Albuquerque, F A; Amaral Junior, A T; Vivas, M; Rodovalho, M A

2014-08-26

The fall armyworm, Spodoptera frugiperda, is the pest that causes the greatest economic losses for both common corn and popcorn crops, and the use of resistant plant genotypes is an important tool for integrated pest management. The goal of the present study was to evaluate the damage caused by S. frugiperda on single-cross popcorn hybrids under field conditions with natural infestation as well as to study the effect of 11 popcorn hybrids on the S. frugiperda life cycle under laboratory conditions. A completely randomized block design with 4 replicates was used for the field experiment, and a completely randomized design with 10 replicates was used for the laboratory experiment. In the field experiment, the damage caused by fall armyworm, grain yield, and popping expansion were quantified, and a diallel analysis was performed to select the best hybrids. For the laboratory experiment, caterpillars were obtained from laboratory cultures kept on an artificial diet and were fed with leaves from the 11 hybrids. Hybrids P7.0 x P9.4, P7.1 x P9.6, P7.2.0 x P9.3, P7.4.0 x P9.1 and P7.4.1 x P9.4 exhibited negative specific combining ability for injury by fall armyworm and positive specific combining ability for yield and popping expansion. In the laboratory experiment, the hybrids influenced the mean larval stage duration, mean larval mass, final larval mass, pupal stage duration, mean pupal mass, and adult longevity.

Mechanism for detecting NAPL using electrical resistivity imaging.

PubMed

Halihan, Todd; Sefa, Valina; Sale, Tom; Lyverse, Mark

2017-10-01

The detection of non-aqueous phase liquid (NAPL) related impacts in freshwater environments by electrical resistivity imaging (ERI) has been clearly demonstrated in field conditions, but the mechanism generating the resistive signature is poorly understood. An electrical barrier mechanism which allows for detecting NAPLs with ERI is tested by developing a theoretical basis for the mechanism, testing the mechanism in a two-dimensional sand tank with ERI, and performing forward modeling of the laboratory experiment. The NAPL barrier theory assumes at low bulk soil NAPL concentrations, thin saturated NAPL barriers can block pore throats and generate a detectable electrically resistive signal. The sand tank experiment utilized a photographic technique to quantify petroleum saturation, and to help determine whether ERI can detect and quantify NAPL across the water table. This experiment demonstrates electrical imaging methods can detect small quantities of NAPL of sufficient thickness in formations. The bulk volume of NAPL is not the controlling variable for the amount of resistivity signal generated. The resistivity signal is primarily due to a zone of high resistivity separate phase liquid blocking current flow through the fully NAPL saturated pores spaces. For the conditions in this tank experiment, NAPL thicknesses of 3.3cm and higher in the formation was the threshold for detectable changes in resistivity of 3% and greater. The maximum change in resistivity due to the presence of NAPL was an increase of 37%. Forward resistivity models of the experiment confirm the barrier mechanism theory for the tank experiment. Copyright © 2017 Elsevier B.V. All rights reserved.

Does it payoff to research economics-A tale of citation, knowledge and economic growth in transition countries

NASA Astrophysics Data System (ADS)

Kovac, Dejan; Scrbec, Nikol; Podobnik, Boris

2018-09-01

There are many economic theories that promote human capital as a key driver of a country's economic growth, but it is challenging to test this theory empirically on a country level and causally interpret the coefficients due to several identification problems. We tried to answer this particular question by using a quasi-natural experiment that happened quarter century ago - the fall of communist block in Eastern Europe. We use a shock to a particular scientific field - economics, to test whether the future investment into that particular field resulted in increased welfare and economic growth. The economics paradigm that was governing all of the communist block ceased to exist. Human capital depreciated over night and all communist countries had to transit from planned economy to a market economy. In the following years countries had to adapt to market economy through additional investment in human capital and research. We find that countries which lack both of the two fourth mentioned components had 25 years later a relatively lower economic growth and wealth. Unlike economics, other fields such as physics and medicine did not go through the same process so we use them as a placebo effect for our study. We find that the relative ratio of citations between economics and physics in post-communist countries is increasing only 15 years after the "paradigm" shock which gives a suggestive evidence that timing of investment into particular scientific field matters the most.

Distribution of the Crustal Magnetic Field in Sichuan-Yunnan Region, Southwest China

PubMed Central

Bai, Chunhua; Kang, Guofa; Gao, Guoming

2014-01-01

Based on the new and higher degree geomagnetic model NGDC-720-V3, we have investigated the spatial distribution, the altitude decay characteristics of the crustal magnetic anomaly, the contributions from different wavelength bands to the anomaly, and the relationship among the anomaly, the geological structure, and the geophysical field in Sichuan-Yunnan region of China. It is noted that the most outstanding feature in this area is the strong positive magnetic anomaly in Sichuan Basin, a geologically stable block. Contrasting with this feature, a strong negative anomaly can be seen nearby in Longmen Mountain block, an active block. This contradiction implies a possible relationship between the magnetic field and the geological activity. Completely different feature in magnetic field distribution is seen in the central Yunnan block, another active region, where positive and negative anomalies distribute alternatively, showing a complex magnetic anomaly map. Some fault belts, such as the Longmen Mountain fault, Lijiang-Xiaojinhe fault, and the Red River fault, are the transitional zones of strong and weak or negative and positive anomalies. The corresponding relationship between the magnetic anomaly and the geophysical fields was confirmed. PMID:25243232

Reversible conduction block in peripheral nerve using electrical waveforms.

PubMed

Bhadra, Niloy; Vrabec, Tina L; Bhadra, Narendra; Kilgore, Kevin L

2018-01-01

Electrical nerve block uses electrical waveforms to block action potential propagation. Two key features that distinguish electrical nerve block from other nonelectrical means of nerve block: block occurs instantly, typically within 1 s; and block is fully and rapidly reversible (within seconds). Approaches for achieving electrical nerve block are reviewed, including kilohertz frequency alternating current and charge-balanced polarizing current. We conclude with a discussion of the future directions of electrical nerve block. Electrical nerve block is an emerging technique that has many significant advantages over other methods of nerve block. This field is still in its infancy, but a significant expansion in the clinical application of this technique is expected in the coming years.

Ultrafast NMR diffusion measurements exploiting chirp spin echoes.

PubMed

Ahola, Susanna; Mankinen, Otto; Telkki, Ville-Veikko

2017-04-01

Standard diffusion NMR measurements require the repetition of the experiment multiple times with varying gradient strength or diffusion delay. This makes the experiment time-consuming and restricts the use of hyperpolarized substances to boost sensitivity. We propose a novel single-scan diffusion experiment, which is based on spatial encoding of two-dimensional data, employing the spin-echoes created by two successive adiabatic frequency-swept chirp π pulses. The experiment is called ultrafast pulsed-field-gradient spin-echo (UF-PGSE). We present a rigorous derivation of the echo amplitude in the UF-PGSE experiment, justifying the theoretical basis of the method. The theory reveals also that the standard analysis of experimental data leads to a diffusion coefficient value overestimated by a few per cent. Although the overestimation is of the order of experimental error and thus insignificant in many practical applications, we propose that it can be compensated by a bipolar gradient version of the experiment, UF-BP-PGSE, or by corresponding stimulated-echo experiment, UF-BP-pulsed-field-gradient stimulated-echo. The latter also removes the effect of uniform background gradients. The experiments offer significant prospects for monitoring fast processes in real time as well as for increasing the sensitivity of experiments by several orders of magnitude by nuclear spin hyperpolarization. Furthermore, they can be applied as basic blocks in various ultrafast multidimensional Laplace NMR experiments. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Block Distribution Analysis of Impact Craters in the Tharsis and Elysium Planitia Regions on Mars

NASA Astrophysics Data System (ADS)

Button, N.; Karunatillake, S.; Diaz, C.; Zadei, S.; Rajora, V.; Barbato, A.; Piorkowski, M.

2017-12-01

The block distribution pattern of ejecta surrounding impact craters reveals clues about their formation. Using images from High Resolution Imaging Science Experiment (HiRISE) image onboard the Mars Reconnaissance Orbiter (MRO), we indentified two rayed impact craters on Mars with measurable ejecta fields to quantitatively investigate in this study. Impact Crater 1 (HiRISE image PSP_008011_1975) is located in the Tharsis region at 17.41°N, 248.75°E and is 175 m in diameter. Impact Crater 2 (HiRISE image ESP_018352_1805) is located in Elysium Planitia at 0.51°N, 163.14°E and is 320 m in diameter. Our block measurements, used to determine the area, were conducted using HiView. Employing methods similar to Krishna and Kumar (2016), we compared block size and axis ratio to block distance from the center of the crater, impact angle, and direction. Preliminary analysis of sixteen radial sectors around Impact Crater 1 revealed that in sectors containing mostly small blocks (less than 10 m2), the small blocks were ejected up to three times the diameter of the crater from the center of the crater. These small block-dominated sectors lacked blocks larger than 10 m2. Contrastingly, in large block-dominated sectors (larger than 30 m2) blocks rarely traveled farther than 200 m from the center of the crater. We also seek to determine the impact angle and direction. Krishna and Kumar (2016) calculate the b-value (N(a) = Ca-b; "N(a) equals the number of fragments or craters with a size greater than a, C is a constant, and -b is a power index") as a method to determine the impact direction. Our preliminary results for Impact Crater 1 did not clearly indicate the impact angle. With improved measurements and the assessment of Impact Crater 2, we will compare Impact Crater 1 to Impact Crater 2 as well as assess the impact angle and direction in order to determine if the craters are secondary craters. Hood, D. and Karunatillake, S. (2017), LPSC, Abstract #2640 Krishna, N., and P. S. Kumar (2016), Icarus, 264, 274-299

Overdose problem associated with treatment planning software for high energy photons in response of Panama's accident.

PubMed

Attalla, Ehab M; Lotayef, Mohamed M; Khalil, Ehab M; El-Hosiny, Hesham A; Nazmy, Mohamed S

2007-06-01

The purpose of this study was to quantify dose distribution errors by comparing actual dose measurements with the calculated values done by the software. To evaluate the outcome of radiation overexposure related to Panama's accident and in response to ensure that the treatment planning systems (T.P.S.) are being operated in accordance with the appropriate quality assurance programme, we studied the central axis and pripheral depth dose data using complex field shaped with blocks to quantify dose distribution errors. Multidata T.P.S. software versions 2.35 and 2.40 and Helax T.P.S. software version 5.1 B were assesed. The calculated data of the software treatment planning systems were verified by comparing these data with the actual dose measurements for open and blocked high energy photon fields (Co-60, 6MV & 18MV photons). Close calculated and measured results were obtained for the 2-D (Multidata) and 3-D treatment planning (TMS Helax). These results were correct within 1 to 2% for open fields and 0.5 to 2.5% for peripheral blocked fields. Discrepancies between calculated and measured data ranged between 13. to 36% along the central axis of complex blocked fields when normalisation point was selected at the Dmax, when the normalisation point was selected near or under the blocks, the variation between the calculated and the measured data was up to 500% difference. The present results emphasize the importance of the proper selection of the normalization point in the radiation field, as this facilitates detection of aberrant dose distribution (over exposure or under exposure).

Block rotations, fault domains and crustal deformation in the western US

NASA Technical Reports Server (NTRS)

Nur, Amos

1990-01-01

The aim of the project was to develop a 3D model of crustal deformation by distributed fault sets and to test the model results in the field. In the first part of the project, Nur's 2D model (1986) was generalized to 3D. In Nur's model the frictional strength of rocks and faults of a domain provides a tight constraint on the amount of rotation that a fault set can undergo during block rotation. Domains of fault sets are commonly found in regions where the deformation is distributed across a region. The interaction of each fault set causes the fault bounded blocks to rotate. The work that has been done towards quantifying the rotation of fault sets in a 3D stress field is briefly summarized. In the second part of the project, field studies were carried out in Israel, Nevada and China. These studies combined both paleomagnetic and structural information necessary to test the block rotation model results. In accordance with the model, field studies demonstrate that faults and attending fault bounded blocks slip and rotate away from the direction of maximum compression when deformation is distributed across fault sets. Slip and rotation of fault sets may continue as long as the earth's crustal strength is not exceeded. More optimally oriented faults must form, for subsequent deformation to occur. Eventually the block rotation mechanism may create a complex pattern of intersecting generations of faults.

Colostomy with Transversus Abdominis Plane Block

PubMed Central

Tekelioğlu, Ümit Yaşar; Demirhan, Abdullah; Şit, Mustafa; Kurt, Adem Deniz; Bilgi, Murat; Koçoğlu, Hasan

2015-01-01

Transversus abdominis plane (TAP) block is one of the abdominal field block. The TAP block is used for both anaesthetic management and post-operative pain therapy in lower abdominal surgery. TAP block is a procedure in which local anaesthetic agents are applied to the anatomic neurofacial space between the internal oblique and the transversus abdominis muscle. TAP block is a good method for post-operative pain control as well as allows for short operations involving the abdominal area. In this article, a case of colostomy under TAP block is presented. PMID:27366540

Heave, settlement and fracture of chalk during physical modelling experiments with temperature cycling above and below 0 °C

NASA Astrophysics Data System (ADS)

Murton, Julian B.; Ozouf, Jean-Claude; Peterson, Rorik

2016-10-01

To elucidate the early stages of heave, settlement and fracture of intact frost-susceptible rock by temperature cycling above and below 0 °C, two physical modelling experiments were performed on 10 rectangular blocks 450 mm high of fine-grained, soft limestone. One experiment simulated 21 cycles of bidirectional freezing (upward and downward) of an active layer above permafrost, and the other simulated 26 cycles of unidirectional freezing (downward) of a seasonally frozen bedrock in a non-permafrost region. Heave and settlement of the top of the blocks were monitored in relation to rock temperature and unfrozen water content, which ranged from almost dry to almost saturated. In the bidirectional freezing experiment, heave of the wettest block initially occurred abruptly at the onset of freezing periods and gradually during thawing periods (summer heave). After the crossing of a threshold marked by the appearance of a macrocrack in the upper layer of permafrost, summer heave increased by an order of magnitude as segregated ice accumulated incrementally in macrocracks, interrupted episodically by abrupt settlement that coincided with unusually high air temperatures. In the unidirectional freezing experiment, the wet blocks heaved during freezing periods and settled during thawing periods, whereas the driest blocks showed the opposite behaviour. The two wettest blocks settled progressively during the first 15 freeze-thaw cycles, before starting to heave progressively as macrocracks developed. Four processes, operating singly or in combination in the blocks account for their heave and settlement: (1) thermal expansion and contraction caused heave and settlement when little or no water-ice phase change was involved; (2) volumetric expansion of water freezing in situ caused short bursts of heave of the outer millimetres of wet rock; (3) ice segregation deeper in the blocks caused sustained heave during thawing and freezing periods; and (4) freeze-thaw cycling caused consolidation and settlement of wet blocks prior to macrocracking in the unidirectional freezing experiment. Rock fracture developed by growth of segregated ice in microcracks and macrocracks at depths determined by the freezing regime. Overall, the heave, settlement and fracture behaviour of the limestone is similar to that of frost-susceptible soil.

Using Quilt Blocks to Construct Understanding

ERIC Educational Resources Information Center

Westegaard, Susanne K.

2008-01-01

The article documents student experiences with quilt blocks in a mathematics classroom. Using blocks as tools, students construct their understanding of perimeter, area, probability, and transformations. (Contains 9 figures.)

Dynamic Characteristics of Regional Flows around the Pyrénées in View of the PYREX Experiment. Part I: Analysis of the Pressure and Wind Fields and Experimental Assessment of the Applicability of the Linear Theory.

NASA Astrophysics Data System (ADS)

Bénech, B.; Koffi, E.; Druilhet, A.; Durand, P.; Bessemoulin, P.; Campins, J.; Jansa, A.; Terliuc, B.

1998-01-01

regarding (a) the perturbation of the surface pressure field, which resembles the predicted bipolar distribution; (b) the dependence of the drag on Fr1, which enables the assessment of the linear theory and the definition of the conditions of applicability of two models [(i) a two-dimensional model, for which it was possible to define quantitatively the effective blocked area, and (ii) a three-dimensional model, for which a scaling function that combines the direction of incidence, the mountain shape, and the Coriolis effect was found almost constant, with an average value of 0.2 for all the cases under study]; (c) the extension of the area affected by the blocking effect, estimated to be 4.5-5 times the width of the barrier and the drift of the strong deceleration point due to the Coriolis effect; (d) the dependence of the wind velocities on Fr1 at the edges of the barrier; and (e) the asymmetric flow deviation induced by the Coriolis effect and biased by the departure of the flow from normal incidence.

Switchable pH-responsive polymeric membranes prepared via block copolymer micelle assembly.

PubMed

Nunes, Suzana P; Behzad, Ali Reza; Hooghan, Bobby; Sougrat, Rachid; Karunakaran, Madhavan; Pradeep, Neelakanda; Vainio, Ulla; Peinemann, Klaus-Viktor

2011-05-24

A process is described to manufacture monodisperse asymmetric pH-responsive nanochannels with very high densities (pore density >2 × 10(14) pores per m(2)), reproducible in m(2) scale. Cylindric pores with diameters in the sub-10 nm range and lengths in the 400 nm range were formed by self-assembly of metal-block copolymer complexes and nonsolvent-induced phase separation. The film morphology was tailored by taking into account the stability constants for a series of metal-polymer complexes and confirmed by AFM. The distribution of metal-copolymer micelles was imaged by transmission electron microscopy tomography. The pH response of the polymer nanochannels is the strongest reported with synthetic pores in the nm range (reversible flux increase of more than 2 orders of magnitude when switching the pH from 2 to 8) and could be demonstrated by cryo-field emission scanning electron microscopy, SAXS, and ultra/nanofiltration experiments.

Electron Spin Optical Orientation in Charged Quantum Dots

NASA Astrophysics Data System (ADS)

Shabaev, A.; Gershoni, D.; Korenev, V. L.

2005-03-01

We present a theory of nonresonant optical orientation of electron spins localized in quantum dots. This theory explains the negative circularly polarized photoluminescence of singlet trions localized in quantum dots previously observed in experiments where trion polarization changed to negative with time and where the degree of the negative polarization increased with intensity of pumping light. We have shown that this effect can be explained by the accumulation of dark excitons that occurs due to the spin blocking of the singlet trion formation - the major mechanism of dark exciton recombination. The accumulation of dark excitons results from a lack of electrons with a spin matching the exciton polarization. The electron spin lifetime is shortened by a transverse magnetic field or a temperature increase. This takes the block off the dark exciton recombination and restores the positive degree of trion polarization. The presented theory gives good agreement with experimental data.

Characterizing permanent magnet blocks with Helmholtz coils

NASA Astrophysics Data System (ADS)

Carnegie, D. W.; Timpf, J.

1992-08-01

Most of the insertion devices to be installed at the Advanced Photon Source will utilize permanent magnets in their magnetic structures. The quality of the spectral output is sensitive to the errors in the field of the device which are related to variations in the magnetic properties of the individual blocks. The Advanced Photon Source will have a measurement facility to map the field in the completed insertion devices and equipment to test and modify the magnetic strength of the individual magnet blocks. One component of the facility, the Helmholtz coil permanent magnet block measurement system, has been assembled and tested. This system measures the total magnetic moment vector of a block with a precision better than 0.01% and a directional resolution of about 0.05°. The design and performance of the system will be presented.

East Cameron Block 270, offshore Louisiana: a Pleistocene field

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

Holland, D.S.; Sutley, C.E.; Berlitz, R.E.

1976-01-01

Exploration of the Plio-Pleistocene in the Gulf of Mexico since 1970 has led to the discovery of significant hydrocarbon reserves. One of the better gas fields found to date has been the East Cameron Block 270 field, offshore Louisiana. Utilization of a coordinated exploitation plan with Schlumberger Offshore Services has allowed Pennzoil Co., as operator, to develop and put the Block 270 field on production in minimum time. The structure at Block 270 field is a north-south-trending, faulted nose at 6000 ft (1825 m). At the depth of the ''G'' sandstone (8700 ft or 2650 m), the structure is closed;more » it is elongated north-south and dips in all directions from the Block 270 area. Closure is the result of contemporaneous growth of the east-bounding regional fault. Structural and stratigraphic interpretations from dipmeters were used to determine the most favorable offset locations. The producing zones consist of various combinations of bar-like, channel-like, and distributary-front sandstones. The sediment source for most of the producing zones was southwest of the area, except for two zones which derived their sediments from the north through a system of channels paralleling the east-bounding fault. Computed logs were used to convert conventional logging measurements into a more readily usable form for evaluation. The computed results were used for reserve calculations, reservoir-quality determinations, and confirmation of depositional environments as determined from other sources.« less

Predictor-based multivariable closed-loop system identification of the EXTRAP T2R reversed field pinch external plasma response

NASA Astrophysics Data System (ADS)

Olofsson, K. Erik J.; Brunsell, Per R.; Rojas, Cristian R.; Drake, James R.; Hjalmarsson, Håkan

2011-08-01

The usage of computationally feasible overparametrized and nonregularized system identification signal processing methods is assessed for automated determination of the full reversed-field pinch external plasma response spectrum for the experiment EXTRAP T2R. No assumptions on the geometry of eigenmodes are imposed. The attempted approach consists of high-order autoregressive exogenous estimation followed by Markov block coefficient construction and Hankel matrix singular value decomposition. It is seen that the obtained 'black-box' state-space models indeed can be compared with the commonplace ideal magnetohydrodynamics (MHD) resistive thin-shell model in cylindrical geometry. It is possible to directly map the most unstable autodetected empirical system pole to the corresponding theoretical resistive shell MHD eigenmode.

Magnetic Alignment of Block Copolymer Microdomains by Intrinsic Chain Anisotropy.

PubMed

Rokhlenko, Yekaterina; Gopinadhan, Manesh; Osuji, Chinedum O; Zhang, Kai; O'Hern, Corey S; Larson, Steven R; Gopalan, Padma; Majewski, Paweł W; Yager, Kevin G

2015-12-18

We examine the role of intrinsic chain susceptibility anisotropy in magnetic field directed self-assembly of a block copolymer using in situ x-ray scattering. Alignment of a lamellar mesophase is observed on cooling across the disorder-order transition with the resulting orientational order inversely proportional to the cooling rate. We discuss the origin of the susceptibility anisotropy, Δχ, that drives alignment and calculate its magnitude using coarse-grained molecular dynamics to sample conformations of surface-tethered chains, finding Δχ≈2×10^{-8}. From field-dependent scattering data, we estimate that grains of ≈1.2  μm are present during alignment. These results demonstrate that intrinsic anisotropy is sufficient to support strong field-induced mesophase alignment and suggest a versatile strategy for field control of orientational order in block copolymers.

Simulation Study to Improve Focalization of a Figure Eight Coil by Using a Conductive Shield Plate and a Ferromagnetic Block.

PubMed

Zhao, Chen; Zhang, Shunqi; Liu, Zhipeng; Yin, Tao

2015-07-01

A new method to improve the focalization and efficiency of the Figure of Eight (FOE) coil in rTMS is discussed in this paper. In order to decrease the half width of the distribution curve (HWDC), as well to increase the ratio of positive peak value to negative peak value (RPN) of the induced electric field, a shield plate with a window and a ferromagnetic block are assumed to enhance the positive peak value of the induced electrical field. The shield is made of highly conductive copper, and the block is made of highly permeable soft magnetic ferrite. A computer simulation is conducted on ANSYS® software to conduct the finite element analysis (FEA). Two comparing coefficients were set up to optimize the sizes of the shield window and the block. Simulation results show that a shield with a 60 mm × 30 mm sized window, together with a block 40 mm thick, can decrease the focal area of a FOE coil by 46.7%, while increasing the RPN by 135.9%. The block enhances the peak value of the electrical field induced by a shield-FOE by 8.4%. A real human head model was occupied in this paper to further verify our method.

Encouraging top-down attention in visual search:A developmental perspective.

PubMed

Lookadoo, Regan; Yang, Yingying; Merrill, Edward C

2017-10-01

Four experiments are reported in which 60 younger children (7-8 years old), 60 older children (10-11 years old), and 60 young adults (18-25 years old) performed a conjunctive visual search task (15 per group in each experiment). The number of distractors of each feature type was unbalanced across displays to evaluate participants' ability to restrict search to the smaller subset of features. The use of top-down attention processes to restrict search was encouraged by providing external aids for identifying and maintaining attention on the smaller set. In Experiment 1, no external assistance was provided. In Experiment 2, precues and instructions were provided to focus attention on that subset. In Experiment 3, trials in which the smaller subset was represented by the same feature were presented in alternating blocks to eliminate the need to switch attention between features from trial to trial. In Experiment 4, consecutive blocks of the same subset features were presented in the first or second half of the experiment, providing additional consistency. All groups benefited from external support of top-down attention, although the pattern of improvement varied across experiments. The younger children benefited most from precues and instruction, using the subset search strategy when instructed. Furthermore, younger children benefited from blocking trials only when blocks of the same features did not alternate. Older participants benefited from the blocking of trials in both Experiments 3 and 4, but not from precues and instructions. Hence, our results revealed both malleability and limits of children's top-down control of attention.

Inter-rater agreement among orthodontists in a blocked experiment.

PubMed

Korn, E L; Baumrind, S

1985-01-01

Five orthodontists were asked to predict for 64 patients a particular dichotomous outcome of treatment based on pre-treatment X-ray films. The orthodontists rated the cases in blocks of size 4-6 with the knowledge of the number of positive outcomes in each block. We discuss the reasons why this blocked design is appropriate whenever clinicians are asked to rate cases which have not been randomly selected from a clinical practice similar to their own. We give a simple description of the inter-rater agreement for this type of blocked experiment as well as a procedure to test that the agreement is no better than that expected by random independent assignment.

Proceedings of the Conference on the Design of Experiments in Army Research Development and Testing (28th) Held at Monterey, California on 20-22 October 1982

DTIC Science & Technology

1983-06-01

program specifically designed to solve IME equations. The IME measure is a useful index because it translates system performance characteristics of...8.0 SUMMARY The purpose of this study was to design the field evaluation of a camou- flage system in such a manner that the camoufleur could...analysis of complex factorial designs and their associated systems of confounding ((44), [46)) and to the introduction of incomplete block designs . My

Assessment of exit block following pulmonary vein isolation: far-field capture masquerading as entrance without exit block.

PubMed

Vijayaraman, Pugazhendhi; Dandamudi, Gopi; Naperkowski, Angela; Oren, Jess; Storm, Randle; Ellenbogen, Kenneth A

2012-10-01

Complete electrical isolation of pulmonary veins (PVs) remains the cornerstone of ablation therapy for atrial fibrillation. Entrance block without exit block has been reported to occur in 40% of the patients. Far-field capture (FFC) can occur during pacing from the superior PVs to assess exit block, and this may appear as persistent conduction from PV to left atrium (LA). To facilitate accurate assessment of exit block. Twenty consecutive patients with symptomatic atrial fibrillation referred for ablation were included in the study. Once PV isolation (entrance block) was confirmed, pacing from all the bipoles on the Lasso catheter was used to assess exit block by using a pacing stimulus of 10 mA at 2 ms. Evidence for PV capture without conduction to LA was necessary to prove exit block. If conduction to LA was noticed, pacing output was decreased until there was PV capture without conduction to LA or no PV capture was noted to assess for far-field capture in both the upper PVs. All 20 patients underwent successful isolation (entrance block) of all 76 (4 left common PV) veins: mean age 58 ± 9 years; paroxysmal atrial fibrillation 40%; hypertension 70%, diabetes mellitus 30%, coronary artery disease 15%; left ventricular ejection fraction 55% ± 10%; LA size 42 ± 11 mm. Despite entrance block, exit block was absent in only 16% of the PVs, suggesting persistent PV to LA conduction. FFC of LA appendage was noted in 38% of the left superior PVs. FFC of the superior vena cava was noted in 30% of the right superior PVs. The mean pacing threshold for FFC was 7 ± 4 mA. Decreasing pacing output until only PV capture (loss of FFC) is noted was essential to confirm true exit block. FFC of LA appendage or superior vena cava can masquerade as persistent PV to LA conduction. A careful assessment for PV capture at decreasing pacing output is essential to exclude FFC. Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

The State of Human Anatomy Teaching in the Medical Schools of Gulf Cooperation Council Countries: Present and future perspectives.

PubMed

Habbal, Omar

2009-04-01

Available literature on medical education charts an emerging trend in the field of anatomy. In the past decade, assisted by innovations in informatics and the paradigm shift in medical education, the hands-on experience of cadaver dissection has progressively become a relic of the past. Within the context of the situation in Gulf Cooperation Council countries, this paper compares the traditional teaching approach with the modern one that tends to emphasise technical gadgetry, virtual reality and plastic models rather than hands-on-experience to impart knowledge and skill. However, cadaver-based learning is an important building block for the future physician and surgeon since clinical astuteness is likely to rely on skills gained from hands-on experience rather than the tendency to learning through virtual reality found in modern curricula.

Innovative Applications of Laser Scanning and Rapid Prototype Printing to Rock Breakdown Experiments

NASA Technical Reports Server (NTRS)

Bourke, Mary; Viles, Heather; Nicoll, Joe; Lyew-Ayee, Parris; Ghent, Rebecca; Holmlund, James

2008-01-01

We present the novel application of two technologies for use in rock breakdown experiments, i.e. close-range, ground-based 3D triangulation scanning and rapid prototype printing. These techniques aid analyses of form-process interactions across the range of scales relevant to breakdown (micron-m). This is achieved through (a) the creation of DEMs (which permit quantitative description and analysis of rock surface morphology and morphological change) and (b) the production of more realistically-shaped experimental blocks. We illustrate the use of these techniques, alongside appropriate data analysis routines, in experiments designed to investigate the persistence of fluvially-derived features in the face of subsequent wind abrasion and weathering. These techniques have a range of potential applications in experimental field and lab-based geomorphic studies beyond those specifically outlined here.

Dissecting the Hydrobiogeochemical Box

NASA Astrophysics Data System (ADS)

Wang, Y.; Alves Meira Neto, A.; Sengupta, A.; Root, R. A.; Dontsova, K.; Troch, P. A. A.; Chorover, J.

2015-12-01

Soil genesis is a coupled hydrologic and biogeochemical process that involves the interaction of weathering rock surfaces and water. Due to strong nonlinear coupling, it is extremely difficult to predict biogeochemical changes from hydrological modeling in natural field systems. A fully controlled and monitored system with known initial conditions could be utilized to isolate variables and simplify these natural processes. To investigate the initial weathering of host rock to soil, we employed a 10° sloping soil lysimeter containing one cubic meter of crushed and homogenized basaltic rock. A major experiment of the Periodic Tracer Hierarchy (PERTH) method (Harman and Kim, 2014) coupled with its bonus experiment were performed in the past two years. These experimental applications successfully described the transit-time distribution (TTD) of a tracer-enriched water breakthrough curve in this unique hydrological system (Harman, 2015). With intensive irrigation and high volume of water storage throughout the experiments, rapid biological changes have been observed on the soil surface, such as algal and grass growth. These observations imply that geochemical hotspots may be established within the soil lysimeter. To understand the detailed 2D spatial distribution of biogeochemical changes, 100 selected and undisturbed soil blocks, among a total 1000 sub-gridded equal sized, are tested with several geochemical tools. Each selected soil block was subjected to elemental analysis by pXRF to determine if elemental migration is detectable in the dynamic proto-soil development. Synchrotron XRD quantification with Reitveld refinement will follow to clarify mineralogical transformations in the soil blocks. The combined techniques aim to confirm the development of geochemical hotspots; and link these findings with previous hydrological findings from the PERTH experiment as well as other hydrological modeling, such as conducted with Hydrus and CATHY. This work provides insight to the detailed correlations between hydrological and biogeochemical processes during incipient soil formation, as well as aiding the development of advanced tools and methods to study complex Earth-system dynamics.

Performance Investigation of a Handheld 3d Scanner to Define Good Practices for Small Artefact 3d Modeling

NASA Astrophysics Data System (ADS)

Lachat, E.; Landes, T.; Grussenmeyer, P.

2017-08-01

Handheld 3D scanners can be used to complete large scale models with the acquisition of occluded areas or small artefacts. This may be of interest for digitization projects in the field of Cultural Heritage, where detailed areas may require a specific treatment. Such sensors present the advantage of being easily portable in the field, and easily usable even without particular knowledge. In this paper, the Freestyle3D handheld scanner launched on the market in 2015 by FARO is investigated. Different experiments are described, covering various topics such as the influence of range or color on the measurements, but also the precision achieved for geometrical primitive digitization. These laboratory experiments are completed by acquisitions performed on engraved and sculpted stone blocks. This practical case study is useful to investigate which acquisition protocol seems to be the more adapted and leads to precise results. The produced point clouds will be compared to photogrammetric surveys for the purpose of their accuracy assessment.

From conformal blocks to path integrals in the Vaidya geometry

NASA Astrophysics Data System (ADS)

Anous, Tarek; Hartman, Thomas; Rovai, Antonin; Sonner, Julian

2017-09-01

Correlators in conformal field theory are naturally organized as a sum over conformal blocks. In holographic theories, this sum must reorganize into a path integral over bulk fields and geometries. We explore how these two sums are related in the case of a point particle moving in the background of a 3d collapsing black hole. The conformal block expansion is recast as a sum over paths of the first-quantized particle moving in the bulk geometry. Off-shell worldlines of the particle correspond to subdominant contributions in the Euclidean conformal block expansion, but these same operators must be included in order to correctly reproduce complex saddles in the Lorentzian theory. During thermalization, a complex saddle dominates under certain circumstances; in this case, the CFT correlator is not given by the Virasoro identity block in any channel, but can be recovered by summing heavy operators. This effectively converts the conformal block expansion in CFT from a sum over intermediate states to a sum over channels that mimics the bulk path integral.

Characterization of monoclonal antibodies directed against the bovine herpesvirus-1 glycoprotein E and use for the differentiation between vaccinated and infected animals.

PubMed

Letellier, C; Delangre, A; De Smet, A; Kerkhofs, P

2001-12-04

A panel of seven monoclonal antibodies (MAbs) directed against the bovine herpesvirus-1 (BHV-1) glycoprotein E (gE) was obtained. For that purpose, mice were either tolerized to BHV-1 gE-negative virus and then immunized with wild type BHV-1 or immunized with plasmid DNA expressing the gE and gI glycoproteins. The MAbs were characterized by their reactivity with the gE protein or the gE/gI complex and by competition experiments. Results showed that the MAbs were directed against three antigenic domains, two located on the gE glycoprotein and one on the gE/gI complex. Blocking experiments were performed with sera from experimentally vaccinated and infected cattle. A competition was observed between gE-positive bovine sera and six of the seven MAbs. The bovine sera thus recognized two of the three antigenic sites. Field sera were then tested in blocking enzyme-linked immunosorbent assay using one horseradish peroxidase-conjugated MAb. A specificity of 98.2% and a sensitivity of 98.2% compared to the commercially available test were observed.

Magnetic field exposure of commercial airline pilots.

PubMed

Hood; Nicholas; Butler; Lackland; Hoel; Mohr

2000-10-01

PURPOSE: Airline pilots are exposed to magnetic fields generated by the aircraft's electrical and electronic systems. The purpose of this study was to directly measure the flight deck magnetic fields to which commercial airline pilots are exposed when flying on different aircraft types over a 75-hour flight-duty month.METHODS: Magentic field measurements were taken using personal dosimeters capable of measuring magnetic fields in the 40-800 Hz frequency range. Dosimeters were carried by either the Captain or the First Officer on Boeing 737/200, Boeing 747/400, Boeing 767/300ER, and Airbus 320 aircraft. The data were analyzed by aircraft type, with statistics based on block hours. Block hours begin when the aircraft departs the gate prior to take off and end when the aircraft returns to the gate after landing.RESULTS: Approximately 1008 block hours were recorded at a sampling rate of 3 seconds. Total block time exposure to the pilots ranged from a harmonic geometric mean of 6.7 milliGauss (mG) for the Boeing 767/300ER to 12.7 mG for the Boeing 737/200.CONCLUSIONS: Measured flight deck magnetic field levels were substantially above the 0.8 to 1 mG level typically found in the home or office and suggest the need for further study to evaluate potential health effects of long-term exposure.

A role of nucleus accumbens dopamine receptors in the nucleus accumbens core, but not shell, in fear prediction error.

PubMed

Li, Susan S Y; McNally, Gavan P

2015-08-01

Two experiments used an associative blocking design to study the role of dopamine receptors in the nucleus accumbens shell (AcbSh) and core (AcbC) in fear prediction error. Rats in the experimental groups were trained to a visual fear-conditioned stimulus (conditional stimulus [CS]) A in Stage I, whereas rats in the control groups were not. In Stage II, all rats received compound fear conditioning of the visual CSA and an auditory CSB. Rats were later tested for their fear responses to CSB. All rats received microinjections of saline or the D1-D2 receptor antagonist cis-(z)-flupenthixol prior to Stage II. These microinjections targeted either the AcbSh (Experiment 1) or the AcbC (Experiment 2). In each experiment, Stage I fear conditioning of CSA blocked fear learning to CSB. Microinjection of cis-(z)-flupenthixol (10 or 20 μg) into the AcbSh (Experiment 1) had no effect on fear learning or associative blocking. In contrast, microinjection of cis-(z)-flupenthixol (10 or 20 μg) into the AcbC (Experiment 2) attenuated blocking and so enabled fear learning to CSB. These results identify the AcbC as the critical locus for dopamine receptor contributions to fear prediction error and the associative blocking of fear learning. (c) 2015 APA, all rights reserved).

Cue competition effects in human causal learning.

PubMed

Vogel, Edgar H; Glynn, Jacqueline Y; Wagner, Allan R

2015-01-01

Five experiments involving human causal learning were conducted to compare the cue competition effects known as blocking and unovershadowing, in proactive and retroactive instantiations. Experiment 1 demonstrated reliable proactive blocking and unovershadowing but only retroactive unovershadowing. Experiment 2 replicated the same pattern and showed that the retroactive unovershadowing that was observed was interfered with by a secondary memory task that had no demonstrable effect on either proactive unovershadowing or blocking. Experiments 3a, 3b, and 3c demonstrated that retroactive unovershadowing was accompanied by an inflated memory effect not accompanying proactive unovershadowing. The differential pattern of proactive versus retroactive cue competition effects is discussed in relationship to amenable associative and inferential processing possibilities.

Thin sheet casting with electromagnetic pressurization

DOEpatents

Walk, Steven R.; Slepian, R. Michael; Nathenson, Richard D.; Williams, Robert S.

1991-01-01

An apparatus, method and system for the casting of thin strips or strips of metal upon a moving chill block that includes an electromagnet located so that molten metal poured from a reservoir onto the chill block passes into the magnetic field produced by the electromagnet. The electromagnet produces a force on the molten metal on said chill block in the direction toward said chill block in order to enhance thermal contact between the molten metal and the chill block.

Magnetothermal Convection in Nonconducting Diamagnetic and Paramagnetic Fluids

NASA Technical Reports Server (NTRS)

Edwards, Boyd F.; Gray, Donald D.; Huang, Jie

1996-01-01

Nonuniform magnetic fields exert a magnetic body force on electrically nonconducting classical fluids. These include paramagnetic fluids such as gaseous and liquid oxygen and diamagnetic fluids such as helium. Recent experiments show that this force can overwhelm the force of gravity even at the surface of the earth; it can levitate liquids and gases, quench candle flames, block gas flows, and suppress heat transport. Thermal gradients render the magnetic force nonuniform through the temperature-dependent magnetic susceptibility. These thermal gradients can therefore drive magnetic convection analogous to buoyancy-driven convection. This magnetothermal convection can overwhelm convection driven by gravitational buoyancy in terrestrial experiments. The objectives of the proposed ground-based theoretical study are (a) to supply the magnetothermohydrodynamic theory necessary to understand these recent experiments and (b) to explore the consequences of nonuniform magnetic fields in microgravity. Even the linear theory for the onset of magnetothermal convection is lacking in the literature. We intend to supply the linear and nonlinear theory based on the thermohydrodynamic equations supplemented by the magnetic body force. We intend to investigate the effect of magnetic fields on gas blockage and heat transport in microgravity. Since magnetic fields provide a means of creating arbitrary, controllable body force distributions, we intend to investigate the possibility of using magnetic fields to position and control fluids in microgravity. We also intend to investigate the possibility of creating stationary terrestrial microgravity environments by using the magnetic force to effectively cancel gravity. These investigations may aid in the design of space-based heat-transfer, combustion, and human-life-support equipment.

APPARATUS FOR PRODUCING IONS OF VAPORIZABLE MATERIALS

DOEpatents

Starr, C.

1957-11-19

This patent relates to electronic discharge devices used as ion sources, and in particular describes an ion source for application in a calutron. The source utilizes two cathodes disposed at opposite ends of a longitudinal opening in an arc block fed with vaporized material. A magnetic field is provided parallel to the length of the arc block opening. The electrons from the cathodes are directed through slits in collimating electrodes into the arc block parallel to the magnetic field and cause an arc discharge to occur between the cathodes, as the arc block and collimating electrodes are at a positive potential with respect to the cathode. The ions are withdrawn by suitable electrodes disposed opposite the arc block opening. When such an ion source is used in a calutron, an arc discharge of increased length may be utilized, thereby increasing the efficiency and economy of operation.

Multi-blocking strategies for the INS3D incompressible Navier-Stokes code

NASA Technical Reports Server (NTRS)

Gatlin, Boyd

1990-01-01

With the continuing development of bigger and faster supercomputers, computational fluid dynamics (CFD) has become a useful tool for real-world engineering design and analysis. However, the number of grid points necessary to resolve realistic flow fields numerically can easily exceed the memory capacity of available computers. In addition, geometric shapes of flow fields, such as those in the Space Shuttle Main Engine (SSME) power head, may be impossible to fill with continuous grids upon which to obtain numerical solutions to the equations of fluid motion. The solution to this dilemma is simply to decompose the computational domain into subblocks of manageable size. Computer codes that are single-block by construction can be modified to handle multiple blocks, but ad-hoc changes in the FORTRAN have to be made for each geometry treated. For engineering design and analysis, what is needed is generalization so that the blocking arrangement can be specified by the user. INS3D is a computer program for the solution of steady, incompressible flow problems. It is used frequently to solve engineering problems in the CFD Branch at Marshall Space Flight Center. INS3D uses an implicit solution algorithm and the concept of artificial compressibility to provide the necessary coupling between the pressure field and the velocity field. The development of generalized multi-block capability in INS3D is described.

Manipulating Traveling Brain Waves with Electric Fields: From Theory to Experiment.

NASA Astrophysics Data System (ADS)

Gluckman, Bruce J.

2004-03-01

Activity waves in disinhibited neocortical slices have been used as a biological model for epileptic seizure propagation [1]. Such waves have been mathematically modeled with integro-differential equations [2] representing non-local reaction diffusion dynamics of an excitable medium with an excitability threshold. Stability and propagation speed of traveling pulse solutions depend strongly on the threshold in the following manner: propagation speed should decrease with increased threshold over a finite range, beyond which the waves become unstable. Because populations of neurons can be polarized with an applied electric field that effectively shifts their threshold for action potential initiation [3], we predicted, and have experimentally verified, that electric fields could be used globally or locally to speed up, slow down and even block wave propagation. [1] Telfeian and Conners, Epilepsia, 40, 1499-1506, 1999. [2] Pinto and Ermentrout, SIAM J. App. Math, 62, 206-225, 2001. [3] Gluckman, et. al. J Neurophysiol. 76, 4202-5, 1996.

Uranium Bioreduction Rates across Scales: Biogeochemical Hot Moments and Hot Spots during a Biostimulation Experiment at Rifle, Colorado

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

Bao, Chen; Wu, Hongfei; Li, Li

2014-09-02

We aim to understand the scale-dependent evolution of uranium bioreduction during a field experiment at a former uranium mill site near Rifle, Colorado. Acetate was injected to stimulate Fe-reducing bacteria (FeRB) and to immobilize aqueous U(VI) to insoluble U(IV). Bicarbonate was coinjected in half of the domain to mobilize sorbed U(VI). We used reactive transport modeling to integrate hydraulic and geochemical data and to quantify rates at the grid block (0.25 m) and experimental field scale (tens of meters). Although local rates varied by orders of magnitude in conjunction with biostimulation fronts propagating downstream, field-scale rates were dominated by thosemore » orders of magnitude higher rates at a few selected hot spots where Fe(III), U(VI), and FeRB were at their maxima in the vicinity of the injection wells. At particular locations, the hot moments with maximum rates negatively corresponded to their distance from the injection wells. Although bicarbonate injection enhanced local rates near the injection wells by a maximum of 39.4%, its effect at the field scale was limited to a maximum of 10.0%. We propose a rate-versus-measurement-length relationship (log R' = -0.63« less

Magnetic alignment of block copolymer microdomains by intrinsic chain anisotropy

DOE PAGES

Rokhlenko, Yekaterina; Yager, Kevin G.; Gopinadhan, Manesh; ...

2015-12-18

We examine the role of intrinsic chain susceptibility anisotropy in magnetic field directed self-assembly of a block copolymer using in situ x-ray scattering. Alignment of a lamellar mesophase is observed on cooling across the disorder-order transition with the resulting orientational order inversely proportional to the cooling rate. We discuss the origin of the susceptibility anisotropy, Δ χ, that drives alignment and calculate its magnitude using coarse-grained molecular dynamics to sample conformations of surface-tethered chains, finding Δ χ ≈ 2×10 –8. From field-dependent scattering data, we estimate that grains of ≈ 1.2 μm are present during alignment. Furthermore, these results demonstratemore » that intrinsic anisotropy is sufficient to support strong field-induced mesophase alignment and suggest a versatile strategy for field control of orientational order in block copolymers.« less

Magnetic alignment of block copolymer microdomains by intrinsic chain anisotropy

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

Rokhlenko, Yekaterina; Yager, Kevin G.; Gopinadhan, Manesh

We examine the role of intrinsic chain susceptibility anisotropy in magnetic field directed self-assembly of a block copolymer using in situ x-ray scattering. Alignment of a lamellar mesophase is observed on cooling across the disorder-order transition with the resulting orientational order inversely proportional to the cooling rate. We discuss the origin of the susceptibility anisotropy, Δ χ, that drives alignment and calculate its magnitude using coarse-grained molecular dynamics to sample conformations of surface-tethered chains, finding Δ χ ≈ 2×10 –8. From field-dependent scattering data, we estimate that grains of ≈ 1.2 μm are present during alignment. Furthermore, these results demonstratemore » that intrinsic anisotropy is sufficient to support strong field-induced mesophase alignment and suggest a versatile strategy for field control of orientational order in block copolymers.« less

Naming Block Structures: A Multimodal Approach

ERIC Educational Resources Information Center

Cohen, Lynn; Uhry, Joanna

2011-01-01

This study describes symbolic representation in block play in a culturally diverse suburban preschool classroom. Block play is "multimodal" and can allow children to experiment with materials to represent the world in many forms of literacy. Combined qualitative and quantitative data from seventy-seven block structures were collected and analyzed.…

Continued development of mature field: west Cameron Block 45 field, Gulf of Mexico

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

Brand, S.R.; Fox, J.F.

Initial acreage acquisition and exploration of the West Cameron Block 45 field, located offshore Louisiana, were based on reconnaissance gravity surveys that revealed an anomalous high across the area. Several phases of development drilling activity have been conducted in the field since its discovery in March 1949. Nearly four decades after initial exploration began, an integrated field study incorporating all available geological, geophysical, petrophysical, and engineering data was undertaken to evaluate the remaining potential of the field. As a result of this study, a detailed structural and stratigraphic framework was developed, the controls on reservoir production performance were established, andmore » additional drillable prospects were delineated.« less

New pain-relieving strategies for topical photodynamic therapy

NASA Astrophysics Data System (ADS)

Halldin, Christina B.; Paoli, John; Sandberg, Carin; Ericson, Marica B.; Gonzalez, Helena; Wennberg, Ann-Marie

2009-06-01

PDT is an effective method when treating multiple actinic keratoses (field cancerization). The major side effect is pain. Our objectives were to investigate the pain-relieving effect of transcutaneous electrical nerve stimulation (TENS) and peripheral nerve blocks during PDT of field cancerization (FC) of the face and scalp. Patients with field cancerization were included in three studies. In the first study, we examined TENS with an application site on the adjacent dermatome from the PDT area in order to allow the use of water spray during PDT for FC of the scalp and face. In the second study, patients with FC in the facial area received unilateral supraorbital, infraorbital and/or mental nerve blocks. The non-anaesthetised side of the treatment area served as control. In the third study, with similar methodology as in the second study, occipital and supraorbital nerve blocks were combined for FC of the forehead and scalp. The results of the studies strongly support the use of nerve blocks as pain relief during PDT. The use of TENS provided a limited pain reduction, but TENS might be an alternative if the patient disapproves of the use of nerve blocks or is afraid of injections.

The Effect of Virus-Blocking Wolbachia on Male Competitiveness of the Dengue Vector Mosquito, Aedes aegypti

PubMed Central

Segoli, Michal; Hoffmann, Ary A.; Lloyd, Jane; Omodei, Gavin J.; Ritchie, Scott A.

2014-01-01

Background The bacterial endosymbiont Wolbachia blocks the transmission of dengue virus by its vector mosquito Aedes aegypti, and is currently being evaluated for control of dengue outbreaks. Wolbachia induces cytoplasmic incompatibility (CI) that results in the developmental failure of offspring in the cross between Wolbachia-infected males and uninfected females. This increases the relative success of infected females in the population, thereby enhancing the spread of the beneficial bacterium. However, Wolbachia spread via CI will only be feasible if infected males are sufficiently competitive in obtaining a mate under field conditions. We tested the effect of Wolbachia on the competitiveness of A. aegypti males under semi-field conditions. Methodology/Principal Findings In a series of experiments we exposed uninfected females to Wolbachia-infected and uninfected males simultaneously. We scored the competitiveness of infected males according to the proportion of females producing non-viable eggs due to incompatibility. We found that infected males were equally successful to uninfected males in securing a mate within experimental tents and semi-field cages. This was true for males infected by the benign wMel Wolbachia strain, but also for males infected by the virulent wMelPop (popcorn) strain. By manipulating male size we found that larger males had a higher success than smaller underfed males in the semi-field cages, regardless of their infection status. Conclusions/Significance The results indicate that Wolbachia infection does not reduce the competitiveness of A. aegypti males. Moreover, the body size effect suggests a potential advantage for lab-reared Wolbachia-males during a field release episode, due to their better nutrition and larger size. This may promote Wolbachia spread via CI in wild mosquito populations and underscores its potential use for disease control. PMID:25502564

The effect of virus-blocking Wolbachia on male competitiveness of the dengue vector mosquito, Aedes aegypti.

PubMed

Segoli, Michal; Hoffmann, Ary A; Lloyd, Jane; Omodei, Gavin J; Ritchie, Scott A

2014-12-01

The bacterial endosymbiont Wolbachia blocks the transmission of dengue virus by its vector mosquito Aedes aegypti, and is currently being evaluated for control of dengue outbreaks. Wolbachia induces cytoplasmic incompatibility (CI) that results in the developmental failure of offspring in the cross between Wolbachia-infected males and uninfected females. This increases the relative success of infected females in the population, thereby enhancing the spread of the beneficial bacterium. However, Wolbachia spread via CI will only be feasible if infected males are sufficiently competitive in obtaining a mate under field conditions. We tested the effect of Wolbachia on the competitiveness of A. aegypti males under semi-field conditions. In a series of experiments we exposed uninfected females to Wolbachia-infected and uninfected males simultaneously. We scored the competitiveness of infected males according to the proportion of females producing non-viable eggs due to incompatibility. We found that infected males were equally successful to uninfected males in securing a mate within experimental tents and semi-field cages. This was true for males infected by the benign wMel Wolbachia strain, but also for males infected by the virulent wMelPop (popcorn) strain. By manipulating male size we found that larger males had a higher success than smaller underfed males in the semi-field cages, regardless of their infection status. The results indicate that Wolbachia infection does not reduce the competitiveness of A. aegypti males. Moreover, the body size effect suggests a potential advantage for lab-reared Wolbachia-males during a field release episode, due to their better nutrition and larger size. This may promote Wolbachia spread via CI in wild mosquito populations and underscores its potential use for disease control.

An Optimized Multicolor Point-Implicit Solver for Unstructured Grid Applications on Graphics Processing Units

NASA Technical Reports Server (NTRS)

Zubair, Mohammad; Nielsen, Eric; Luitjens, Justin; Hammond, Dana

2016-01-01

In the field of computational fluid dynamics, the Navier-Stokes equations are often solved using an unstructuredgrid approach to accommodate geometric complexity. Implicit solution methodologies for such spatial discretizations generally require frequent solution of large tightly-coupled systems of block-sparse linear equations. The multicolor point-implicit solver used in the current work typically requires a significant fraction of the overall application run time. In this work, an efficient implementation of the solver for graphics processing units is proposed. Several factors present unique challenges to achieving an efficient implementation in this environment. These include the variable amount of parallelism available in different kernel calls, indirect memory access patterns, low arithmetic intensity, and the requirement to support variable block sizes. In this work, the solver is reformulated to use standard sparse and dense Basic Linear Algebra Subprograms (BLAS) functions. However, numerical experiments show that the performance of the BLAS functions available in existing CUDA libraries is suboptimal for matrices representative of those encountered in actual simulations. Instead, optimized versions of these functions are developed. Depending on block size, the new implementations show performance gains of up to 7x over the existing CUDA library functions.

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

Hora, H.; Korn, G.; Eliezer, S.

Measured highly elevated gains of proton–boron (HB11) fusion (Picciottoet al., Phys. Rev. X4, 031030 (2014)) confirmed the exceptional avalanche reaction process (Lalousiset al., Laser Part. Beams 32, 409 (2014); Horaet al., Laser Part. Beams33, 607 (2015)) for the combination of the non-thermal block ignition using ultrahigh intensity laser pulses of picoseconds duration. The ultrahigh accelerationabovemore » $$10^{20}~\\text{cm}~\\text{s}^{-2}$$ for plasma blocks was theoretically and numerically predicted since 1978 (Hora,Physics of Laser Driven Plasmas(Wiley, 1981), pp. 178 and 179) and measured (Sauerbrey, Phys. Plasmas3, 4712 (1996)) in exact agreement (Horaet al., Phys. Plasmas14, 072701 (2007)) when the dominating force was overcoming thermal processes. This is based on Maxwell’s stress tensor by the dielectric properties of plasma leading to the nonlinear (ponderomotive) force $$f_{\\text{NL}}$$ resulting in ultra-fast expanding plasma blocks by a dielectric explosion. Combining this with measured ultrahigh magnetic fields and the avalanche process opens an option for an environmentally absolute clean and economic boron fusion power reactor. Finally, this is supported also by other experiments with very high HB11 reactions under different conditions (Labauneet al., Nature Commun.4, 2506 (2013)).« less

Magnetic Heating of Iron Oxide Nanoparticles and Magnetic Micelles for Cancer Therapy.

PubMed

Glover, Amanda L; Bennett, James B; Pritchett, Jeremy S; Nikles, Sarah M; Nikles, David E; Nikles, Jacqueline A; Brazel, Christopher S

2013-01-01

The inclusion of magnetic nanoparticles into block copolymer micelles was studied towards the development of a targeted, magnetically triggered drug delivery system for cancer therapy. Herein, we report the synthesis of magnetic nanoparticles and poly(ethylene glycol-b-caprolactone) block copolymers, and experimental verification of magnetic heating of the nanoparticles, self-assembly of the block copolymers to form magnetic micelles, and thermally-enhanced drug release. The semicrystalline core of the micelles melted at temperatures just above physiological conditions, indicating that they could be used to release a chemotherapy agent from a thermo-responsive polymer system. The magnetic nanoparticles were shown to heat effectively in high frequency magnetic fields ranging from 30-70 kA/m. Magnetic micelles also showed heating properties, that when combined with a chemotherapeutic agent and a targeting ligand could be developed for localized, triggered drug delivery. During the magnetic heating experiments, a time lag was observed in the temperature profile for magnetic micelles, likely due to the heat of fusion of melting of polycaprolactone micelle cores before bulk solution temperatures increased. Doxorubicin, incorporated into the micelles, released faster when the micelles were heated above the core melting point.

Reynolds-Averaged Navier-Stokes Simulations of Two Partial-Span Flap Wing Experiments

NASA Technical Reports Server (NTRS)

Takalluk, M. A.; Laflin, Kelly R.

1998-01-01

Structured Reynolds Averaged Navier-Stokes simulations of two partial-span flap wing experiments were performed. The high-lift aerodynamic and aeroacoustic wind-tunnel experiments were conducted at both the NASA Ames 7-by 10-Foot Wind Tunnel and at the NASA Langley Quiet Flow Facility. The purpose of these tests was to accurately document the acoustic and aerodynamic characteristics associated with the principle airframe noise sources, including flap side-edge noise. Specific measurements were taken that can be used to validate analytic and computational models of the noise sources and associated aerodynamic for configurations and conditions approximating flight for transport aircraft. The numerical results are used to both calibrate a widely used CFD code, CFL3D, and to obtain details of flap side-edge flow features not discernible from experimental observations. Both experimental set-ups were numerically modeled by using multiple block structured grids. Various turbulence models, grid block-interface interaction methods and grid topologies were implemented. Numerical results of both simulations are in excellent agreement with experimental measurements and flow visualization observations. The flow field in the flap-edge region was adequately resolved to discern some crucial information about the flow physics and to substantiate the merger of the two vortical structures. As a result of these investigations, airframe noise modelers have proposed various simplified models which use the results obtained from the steady-state computations as input.

Reports on block rotations, fault domains and crustal deformation

NASA Technical Reports Server (NTRS)

Nur, Amos

1990-01-01

Studies of block rotations, fault domains and crustal deformation in the western United States, Israel, and China are discussed. Topics include a three-dimensional model of crustal fracture by distributed fault sets, distributed deformation and block rotation in 3D, stress field rotation, and multiple strike slip fault sets.

Video Image Stabilization and Registration

NASA Technical Reports Server (NTRS)

Hathaway, David H. (Inventor); Meyer, Paul J. (Inventor)

2002-01-01

A method of stabilizing and registering a video image in multiple video fields of a video sequence provides accurate determination of the image change in magnification, rotation and translation between video fields, so that the video fields may be accurately corrected for these changes in the image in the video sequence. In a described embodiment, a key area of a key video field is selected which contains an image which it is desired to stabilize in a video sequence. The key area is subdivided into nested pixel blocks and the translation of each of the pixel blocks from the key video field to a new video field is determined as a precursor to determining change in magnification, rotation and translation of the image from the key video field to the new video field.

Video Image Stabilization and Registration

NASA Technical Reports Server (NTRS)

Hathaway, David H. (Inventor); Meyer, Paul J. (Inventor)

2003-01-01

A method of stabilizing and registering a video image in multiple video fields of a video sequence provides accurate determination of the image change in magnification, rotation and translation between video fields, so that the video fields may be accurately corrected for these changes in the image in the video sequence. In a described embodiment, a key area of a key video field is selected which contains an image which it is desired to stabilize in a video sequence. The key area is subdivided into nested pixel blocks and the translation of each of the pixel blocks from the key video field to a new video field is determined as a precursor to determining change in magnification, rotation and translation of the image from the key video field to the new video field.

Adsorption of copolymers at polymer/air and polymer/solid interfaces

NASA Astrophysics Data System (ADS)

Oslanec, Robert

Using mainly low-energy forward recoil spectrometry (LE-FRES) and neutron reflectivity (NR), copolymer behavior at polymer/air and polymer/solid interfaces is investigated. For a miscible blend of poly(styrene-ran-acrylonitrile) copolymers, the volume fraction profile of the copolymer with lower acrylonitrile content is flat near the surface in contrast to mean field predictions. Including copolymer polydispersity into a self consistent mean field (SCMF) model does not account for this profile shape. LE-FRES and NR is also used to study poly(deuterated styrene-block-methyl-methacrylate) (dPS-b-PMMA) adsorption from a polymer matrix to a silicon oxide substrate. The interfacial excess, zsp*, layer thickness, L, and layer-matrix width, w, depend strongly on the number of matrix segments, P, for P 2N, the matrix chains are repelled from the adsorbed layer and the layer characteristics become independent of P. An SCMF model of block copolymer adsorption is developed. SCMF predictions are in qualitative agreement with the experimental behavior of zsp*, L, and w as a function of P. Using this model, the interaction energy of the MMA block with the oxide substrate is found to be -8ksb{B}T. In a subsequent experiment, the matrix/dPS interaction is made increasingly unfavorable by increasing the 4-bromostyrene mole fraction, x, in a poly(styrene-ran-4-bromostyrene) (PBrsbxS) matrix. Whereas experiments show that zsp* slightly decreases as x increases, the SCMF model predicts that zsp* should increase as the matrix becomes more unfavorable. Upon including a small matrix attraction for the substrate, the SCMF model shows that zsp* decreases with x because of competition between PBrsbxS and dPS-b-PMMA for adsorbing sites. In thin film dewetting experiments on silicon oxide, the addition of dPS-b-PMMA to PS coatings acts to slow hole growth and prevent holes from impinging. Dewetting studies show that longer dPS-b-PMMA chains are more effective stabilizing agents than shorter ones and that 3 volume percent dPS-b-PMMA is the optimum additive concentration for this system. For a dPS-b-PMMA:PS blend, atomic force microscopy of the hole floor reveals mounds of residual polymer and a modulated contact line where the rim meets the substrate.

Cation reordering in natural titanomagnetites and implications for paleointensity studies

NASA Astrophysics Data System (ADS)

Bowles, J. A.; Jackson, M. J.; Gee, J. S.

2013-05-01

Successful paleointensity experiments hinge on the underlying assumption of reciprocity; the remanence acquired over a particular temperature range should be fully removed over the same temperature range, and vice versa. This means that the blocking (TB) and unblocking (TUB) temperature spectra are identical and do not change during the course of the experiment. We will present the results of recent work demonstrating that some natural titanomagnetites undergo cation reordering on laboratory timescales and at temperatures at or below the Curie temperature (TC). The bulk composition of the titanomagnetites (Fe3-xTixO4) varies between approximately 0.2 < x < 0.4, with moderate degrees of Mg and Al substitution. Although there is no attendant structural or chemical alteration, the re-distribution of ferric and ferrous iron cations results in reversible changes in Curie temperature of up to 150°C. This necessarily changes the blocking temperature spectrum as a function of prior thermal history. These changes in TC, TUB and TB clearly pose problems for all paleointensity experiments, but the effects may be most apparent during Thellier-type experiments where the sample is step-wise heated to increasingly higher temperatures. The blocking temperature distribution will be expected to change over the course of the experiment even in the absence of chemical alteration, and one can expect the experiment to fail. We will explore the effects of cation redistribution on paleointensity experiments through numerical models and by comparison with paleointensity data from pumice samples taken from the 1980 pyroclastic flows at Mt. St. Helens (MSH). In the MSH samples, two phases are typically present: a predominantly multi-domain, homogeneous titanomagnetite (associated with the cation reordering) and an oxyexsolved, single-domain to pseudo-single-domain phase with ilmenite lamellae in a magnetite-rich host. Samples that result in technically successful paleointensity experiments that give the correct field value are most likely to be dominated by the oxyexsolved phase. By contrast, samples with a considerable proportion of the homogeneous phase typically fail the paleointensity experiments and have unstable magnetization behavior at temperatures associated with cation reordering on laboratory time scales. In many samples with both phases, pTRM checks pass at both low (<300°C) and high (>500°C) temperatures, but fail in the intermediate temperature window. The composition of the titanomagnetites that exhibit this cation reordering effect are extremely common in rocks of andesitic, dacitic, and rhyolitic composition, as well as in some basalts. Cation reordering may therefore be a previously unrecognized cause for failure in paleointensity experiments.

Transport and Depositional Model for Large Country Rock Blocks Within the Searchlight Pluton, Southern Nevada

NASA Astrophysics Data System (ADS)

Perrault, D. S.; Furbish, D. J.; Miller, C. F.

2006-05-01

Searchlight pluton, a steeply tilted, 10 km thick Miocene intrusion in the Colorado River Extensional Corridor, exposes a zone with abundant, 5-400 m long blocks of Proterozoic gneiss. Blocks are present within a pair of subparallel horizons that make up a 2 km-thick zone and extend about 6 km laterally away from the pluton's north margin slightly oblique to the initially subhorizontal boundary between the pluton's middle unit (granite) and lower unit (qtz monzonite). Blocks are a variety of Precambrian metasedimentary gneisses, granitic gneisses, and mylonites. Blocks are commonly polylithologic and well foliated, with long and intermediate dimensions parallel to both their own foliation and that of the granitic host. Their average aspect ratio is ~ 4:1. Blocks within these horizons are interpreted as stoped (detached country rock that experience gravity- induced displacement) based on several lines of evidence. First, the distribution and abundances of blocks are not consistent with an isolated panel of wall rock (screen). The zone is laterally discontinuous (local abundances vary from ~ 0-40 %); transects a gradational (cm-m scale) internal contact at a slightly oblique angle; and tapers away from the pluton's margin. Second, while block foliations are homoclinal and show fairly consistent attitudes from block to block, block foliations are discordant with wall rock foliations at the same stratigraphic level (adjacent north wall). Third, mush disturbance features such as schlieren and enhanced feldspar foliation beneath blocks suggest a downward compaction. We interpret the blocks to have been emplaced after wall collapse events. We are using scaled settling experiments to clarify how blocks move within viscous fluids and interact with crystal mushes. The experiments, involving tabular ceramic blocks with density ρ = 1.75-2.20 g cm-3 settling in shampoo (ρ = 1.02 g cm-3) with viscosity μ = 20.35 Pa s, are scaled to order-of-magnitude by the particle Reynolds number (Re ~ 10-2) based on a prototype spherical block of diameter ~ 50 m settling through a crystal free magma with the density (~ 2.25 g cm-3) and viscosity (~ 105 Pa s) of a granitic melt. With low Reynolds number settling, tabular blocks starting from arbitrary orientation tend to become aligned with their long dimension vertical. During alignment fluid shear is focused on the trailing part of the downward facing surface of the block, inducing a torque that tends to upright the block. Settling experiments also provide insights regarding how blocks might interact with mush/melt interfaces. Mushes at sufficiently high crystal content (>50%) stiffen rheologically. Stoped blocks settling on these interfaces may impart stresses that result in localized deformation of the mush (forming schlieren and/or compaction features). We moreover suggest that tabular blocks are deposited with their long axes horizontal at these interfaces; blocks with a geometry controlled by internal structures (e.g. foliation) would on average possess a subparallel alignment of both their geometric shape and internal structure. At sufficiently low Re, this realignment of a tabular block begins as it approaches a semi-rigid surface or interface and the leading fluid boundary layer interacts with the interface; the vertical speed of the block decreases and it begins to deflect and take on a lateral motion.

Stable, polymer-directed and SPION-nucleated magnetic amphiphilic block copolymer nanoprecipitates with readily reversible assembly in magnetic fields

NASA Astrophysics Data System (ADS)

Giardiello, Marco; Hatton, Fiona L.; Slater, Rebecca A.; Chambon, Pierre; North, Jocelyn; Peacock, Anita K.; He, Tao; McDonald, Tom O.; Owen, Andrew; Rannard, Steve P.

2016-03-01

The formation of inorganic-organic magnetic nanocomposites using reactive chemistry often leads to a loss of super-paramagnetisim when conducted in the presence of iron oxide nanoparticles. We present here a low energy and chemically-mild process of co-nanoprecipitation using SPIONs and homopolymers or amphiphilic block copolymers, of varying architecture and hydrophilic/hydrophobic balance, which efficiently generates near monodisperse SPION-containing polymer nanoparticles with complete retention of magnetism, and highly reversible aggregation and redispersion behaviour. When linear and branched block copolymers with inherent water-solubility are used, a SPION-directed nanoprecipitation mechanism appears to dominate the nanoparticle formation presenting new opportunities for tailoring and scaling highly functional systems for a range of applications.The formation of inorganic-organic magnetic nanocomposites using reactive chemistry often leads to a loss of super-paramagnetisim when conducted in the presence of iron oxide nanoparticles. We present here a low energy and chemically-mild process of co-nanoprecipitation using SPIONs and homopolymers or amphiphilic block copolymers, of varying architecture and hydrophilic/hydrophobic balance, which efficiently generates near monodisperse SPION-containing polymer nanoparticles with complete retention of magnetism, and highly reversible aggregation and redispersion behaviour. When linear and branched block copolymers with inherent water-solubility are used, a SPION-directed nanoprecipitation mechanism appears to dominate the nanoparticle formation presenting new opportunities for tailoring and scaling highly functional systems for a range of applications. Electronic supplementary information (ESI) available: Additional experimental details, NMR spectra, GPC chromatograms, kinetics experiments, graphs of nanopreciptate aggregation and cycling studies and SPION characterisation. See DOI: 10.1039/c6nr00788k

The Ambulatory Long-Block: An Accreditation Council for Graduate Medical Education (ACGME) Educational Innovations Project (EIP)

PubMed Central

Schauer, Daniel P.; Diers, Tiffiny; Mathis, Bradley R.; Neirouz, Yvette; Boex, James R.; Rouan, Gregory W.

2008-01-01

Introduction Historical bias toward service-oriented inpatient graduate medical education experiences has hindered both resident education and care of patients in the ambulatory setting. Aim Describe and evaluate a residency redesign intended to improve the ambulatory experience for residents and patients. Setting Categorical Internal Medicine resident ambulatory practice at the University of Cincinnati Academic Health Center. Program Description We created a year-long continuous ambulatory group-practice experience separated from traditional inpatient responsibilities called the long block as an Accreditation Council for Graduate Medical Education Educational Innovations Project. The practice adopted the Chronic Care Model and residents received extensive instruction in quality improvement and interprofessional teams. Program Evaluation The long block was associated with significant increases in resident and patient satisfaction as well as improvement in multiple quality process and outcome measures. Continuity and no-show rates also improved. Discussion An ambulatory long block can be associated with improvements in resident and patient satisfaction, quality measures, and no-show rates. Future research should be done to determine effects of the long block on education and patient care in the long term, and elucidate which aspects of the long block most contribute to improvement. PMID:18612718

Peculiarities of the atmospheric blocking events over the Siberia and Russian Far East region during summertime

NASA Astrophysics Data System (ADS)

Antokhina, Olga Yu.; Devjatova, Elena V.; Mordvinov, Vladimir I.

2017-11-01

We study the atmospheric blocking event evolution peculiarities over the Siberia and Far Eastern region (Russia) during summertime. Compared are two methods to identify blockings: from the 500 hPa (Z500) isobaric surface height distribution, and from the potential temperature at the dynamic tropopause (PV-θ) for every July 1979 through 2016. We revealed the situations, where blockings are identified only in one of the characteristics. Blocking identification by the PV-θ characteristics is complicated in the cases, when its cyclonic part appears to be filled with air masses of the southern origin, due to which there is no meridional gradient reversal in the PV-θ region. In the Z500 region, the difficulties to identify blocking events may arise in those cases, when the baric field fails to adapt to rapid changes in the temperature field associated with the air mass advection. For example, such events often occur over the ocean surface. We performed a synoptic analysis for several blocking events from the data on the velocity field dynamics at 850 hPa and PV-θ supplemented by the analysis of the observational rainfall data at the stations during those events. Distinguished were several stages of the blocking evolution over the Siberia and Far Eastern region that involved air masses from the East Asian summer monsoon region: 1. The formation of a blocking over Western Siberia; 2. Cold inflow on the blocking eastern periphery, the East Asian summer monsoon front activation, and a cyclone formation (east of Lake Baikal), in whose system the monsoon air was actively involved. Such monsoon cyclones, as a rule, are deep long-living formations, and they bring abnormal precipitations; 3. The formation of a ridge or anticyclone east of the monsoon cyclone, caused by the advection of the same monsoon flow, whose part is involved in a cyclone system. In general, the East Asian summer monsoon influence comes to the effects of regeneration and intensification of the blocking circulating systems. Those effects are often accompanied by strong droughts in some regions and floods in others.

From conformal blocks to path integrals in the Vaidya geometry

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

Anous, Tarek; Hartman, Thomas; Rovai, Antonin

Correlators in conformal field theory are naturally organized as a sum over conformal blocks. In holographic theories, this sum must reorganize into a path integral over bulk fields and geometries. We explore how these two sums are related in the case of a point particle moving in the background of a 3d collapsing black hole. The conformal block expansion is recast as a sum over paths of the first-quantized particle moving in the bulk geometry. Off-shell worldlines of the particle correspond to subdominant contributions in the Euclidean conformal block expansion, but these same operators must be included in order tomore » correctly reproduce complex saddles in the Lorentzian theory. During thermalization, a complex saddle dominates under certain circumstances; in this case, the CFT correlator is not given by the Virasoro identity block in any channel, but can be recovered by summing heavy operators. This effectively converts the conformal block expansion in CFT from a sum over intermediate states to a sum over channels that mimics the bulk path integral.« less

From conformal blocks to path integrals in the Vaidya geometry

DOE PAGES

Anous, Tarek; Hartman, Thomas; Rovai, Antonin; ...

2017-09-04

Correlators in conformal field theory are naturally organized as a sum over conformal blocks. In holographic theories, this sum must reorganize into a path integral over bulk fields and geometries. We explore how these two sums are related in the case of a point particle moving in the background of a 3d collapsing black hole. The conformal block expansion is recast as a sum over paths of the first-quantized particle moving in the bulk geometry. Off-shell worldlines of the particle correspond to subdominant contributions in the Euclidean conformal block expansion, but these same operators must be included in order tomore » correctly reproduce complex saddles in the Lorentzian theory. During thermalization, a complex saddle dominates under certain circumstances; in this case, the CFT correlator is not given by the Virasoro identity block in any channel, but can be recovered by summing heavy operators. This effectively converts the conformal block expansion in CFT from a sum over intermediate states to a sum over channels that mimics the bulk path integral.« less

Saturation of conductance in single ion channels: the blocking effect of the near reaction field.

PubMed

Nadler, Boaz; Schuss, Zeev; Hollerbach, Uwe; Eisenberg, R S

2004-11-01

The ionic current flowing through a protein channel in the membrane of a biological cell depends on the concentration of the permeant ion, as well as on many other variables. As the concentration increases, the rate of arrival of bath ions to the channel's entrance increases, and typically so does the net current. This concentration dependence is part of traditional diffusion and rate models that predict Michaelis-Menten current-concentration relations for a single ion channel. Such models, however, neglect other effects of bath concentrations on the net current. The net current depends not only on the entrance rate of ions into the channel, but also on forces acting on ions inside the channel. These forces, in turn, depend not only on the applied potential and charge distribution of the channel, but also on the long-range Coulombic interactions with the surrounding bath ions. In this paper, we study the effects of bath concentrations on the average force on an ion in a single ion channel. We show that the force of the reaction field on a discrete ion inside a channel embedded in an uncharged lipid membrane contains a blocking (shielding) term that is proportional to the square root of the ionic bath concentration. We then show that different blocking strengths yield different behavior of the current-concentration and conductance-concentration curves. Our theory shows that at low concentrations, when the blocking force is weak, conductance grows linearly with concentration, as in traditional models, e.g., Michaelis-Menten formulations. As the concentration increases to a range of moderate shielding, conductance grows as the square root of concentration, whereas at high concentrations, with high shielding, conductance may actually decrease with increasing concentrations: the conductance-concentration curve can invert. Therefore, electrostatic interactions between bath ions and the single ion inside the channel can explain the different regimes of conductance-concentration relations observed in experiments.

Symmetry and Degeneracy in Quantum Mechanics. Self-Duality in Finite Spin Systems

ERIC Educational Resources Information Center

Osacar, C.; Pacheco, A. F.

2009-01-01

The symmetry of self-duality (Savit 1980 "Rev. Mod. Phys. 52" 453) of some models of statistical mechanics and quantum field theory is discussed for finite spin blocks of the Ising chain in a transverse magnetic field. The existence of this symmetry in a specific type of these blocks, and not in others, is manifest by the degeneracy of their…

Magnetic Nature of Light Transmission through a 5-nm Gap.

PubMed

Yang, Hyosim; Kim, Dai-Sik; Kim, Richard H Joon-Yeon; Ahn, Jae Sung; Kang, Taehee; Jeong, Jeeyoon; Lee, Dukhyung

2018-02-09

Slot antennas have been exploited as important building blocks of optical magnetism because their radiations are invoked by the magnetic fields along the axes, as vectorial Babinet principle predicts. However, optical magnetism of a few-nanometer-width slit, for which fascinating applications are found due to the colossal field enhancement but Babinet principle fails due to the nonnegligible thickness, has not been investigated. In this paper, we demonstrated that the magnetic field plays a dominant role in light transmission through a 5-nm slit on a 150-nm-thick gold film. The 5-nm slit was fabricated by atomic layer lithography, and the transmission was investigated for various incident angles by experiment and simulation at 785-nm wavelength. We found that, due to the deep subwavelength gap width, the transmission has the same incident angle dependence as the tangential magnetic field on the metal surface and this magnetic nature of a nanogap holds up to ~100-nm width. Our analysis establishes conditions for nanogap optical magnetism and suggests new possibilities in realizing magnetic-field-driven optical nonlinearities.

High mobility of large mass movements: a study by means of FEM/DEM simulations

NASA Astrophysics Data System (ADS)

Manzella, I.; Lisjak, A.; Grasselli, G.

2013-12-01

Large mass movements, such as rock avalanches and large volcanic debris avalanches are characterized by extremely long propagation, which cannot be modelled using normal sliding friction law. For this reason several studies and theories derived from field observation, physical theories and laboratory experiments, exist to try to explain their high mobility. In order to investigate more into deep some of the processes recalled by these theories, simulations have been run with a new numerical tool called Y-GUI based on the Finite Element-Discrete Element Method FEM/DEM. The FEM/DEM method is a numerical technique developed by Munjiza et al. (1995) where Discrete Element Method (DEM) algorithms are used to model the interaction between different solids, while Finite Element Method (FEM) principles are used to analyze their deformability being also able to explicitly simulate material sudden loss of cohesion (i.e. brittle failure). In particular numerical tests have been run, inspired by the small-scale experiments done by Manzella and Labiouse (2013). They consist of rectangular blocks released on a slope; each block is a rectangular discrete element made of a mesh of finite elements enabled to fragment. These simulations have highlighted the influence on the propagation of block packing, i.e. whether the elements are piled into geometrical ordinate structure before failure or they are chaotically disposed as a loose material, and of the topography, i.e. whether the slope break is smooth and regular or not. In addition the effect of fracturing, i.e. fragmentation, on the total runout have been studied and highlighted.

3D geomechanical modeling and numerical simulation of in-situ stress fields in shale reservoirs: A case study of the lower Cambrian Niutitang formation in the Cen'gong block, South China

NASA Astrophysics Data System (ADS)

Liu, Jingshou; Ding, Wenlong; Yang, Haimeng; Wang, Ruyue; Yin, Shuai; Li, Ang; Fu, Fuquan

2017-08-01

An analysis of the in-situ state of stress in a shale reservoir was performed based on comprehensive information about the subsurface properties from wellbores established during the development of an oil and gas field. Industrial-level shale gas production has occurred in the Niutitang formation of the lower Cambrian Cen'gong block, South China. In this study, data obtained from hydraulic fracturing, drilling-induced fractures, borehole breakout, global positioning system (GPS), and well deviation statistics have been used to determine the orientation of the maximum horizontal principal stress. Additionally, hydraulic fracturing and multi-pole array acoustic logging (XMAC) were used to determine the vertical variations in the in-situ stress magnitude. Based on logging interpretation and mechanical experiments, the spatial distributions of mechanical parameters were obtained by seismic inversion, and a 3D heterogeneous geomechanical model was established using a finite element stress analysis approach to simulate the in-situ stress fields. The effects of depth, faults, rock mechanics, and layer variations on the principal stresses, horizontal stress difference (Δσ), horizontal stress difference coefficient (Kh), and stress type coefficient (Sp) were determined. The results show that the direction of the maximum principal stress is ESE 120°. Additionally, the development zones of natural fractures appear to correlate with regions with high principal stress differences. At depths shallower than 375 m, the stress type is mainly a thrust faulting stress regime. At depths ranging from 375 to 950 m, the stress type is mainly a strike-slip faulting stress regime. When the depth is > 950 m, the stress type is mainly a normal faulting stress regime. Depth, fault orientation, and rock mechanics all affect the type of stress. The knowledge regarding the Cen'gong block is reliable and can improve borehole stability, casing set point determination, well deployment optimization, and fracturing area selection.

How Do They Grow?

ERIC Educational Resources Information Center

Chan, Helen Hsu

2015-01-01

Students' experiences with pattern blocks begin as early as preschool. At that time, they begin to develop an understanding of repetition by alternating the colored shapes to create AB, AAB, or ABC patterns. They experiment with area and symmetry by covering polygonal spaces using the fewest (or the greatest) number of pattern blocks possible or…

Aggregate morphologies of amphiphilic ABC triblock copolymer in dilute solution using self-consistent field theory.

PubMed

Wang, Rong; Tang, Ping; Qiu, Feng; Yang, Yuliang

2005-09-15

The complex microstructures of amphiphilic ABC linear triblock copolymers in which one of the end blocks is relatively short and hydrophilic, and the other two blocks B and C are hydrophobic in a dilute solution, have been investigated by the real-space implementation of self-consistent field theory (SCFT) in two dimensions (2D). In contrast to diblock copolymers in solution, the aggregation of triblock copolymers are more complicated due to the presence of the second hydrophobic blocks and, hence, big ranges of parameter space controlling the morphology. By tailoring the hydrophobic degree and its difference between the blocks B and C, the various shapes of vesicles, circlelike and linelike micelles possibly corresponding to spherelike, and rodlike micelles in 3D, and especially, peanutlike micelles not found in diblock copolymers are observed. The transition from vesicles to circlelike micelles occurs with increasing the hydrophobicity of the blocks B and C, while the transition from circlelike micelles to linelike micelles or from the mixture of micelles and vesicles to the long linelike micelles takes place when the repulsive interaction of the end hydrophobic block C is stronger than that of the middle hydrophobic block B. Furthermore, it is favorable for dispersion of the block copolymer in the solvent into aggregates when the repulsion of the solvent to the end hydrophobic block is larger than that of the solvent to the middle hydrophobic block. Especially when the bulk block copolymers are in a weak segregation regime, the competition between the microphase separation and macrophase separation exists and the large compound micelle-like aggregates are found due to the macrophase separation with increasing the hydrophobic degree of blocks B and C, which is absent in diblock copolymer solution. The simulation results successfully reproduce the existing experimental ones.

Field Experiences with Floating Breakwaters in the Eastern United States.

DTIC Science & Technology

1982-07-01

Island Yacht Club Ocean Avenue Cranston, RI 02905 Coweset Marina 100 Folly l.anding Warwick, RI 02886 John Dicke rson Apponiaug I la rho r ’a r ITn; 21...tire breakwater Wave suppre-ssion 20. AWNrACT r e(theu a en m s if neo and Identyf by block nutmbo) In the past 10 years, the use of floating breakwat...ers A; t’mpo r ;ll’N1 lt .1 structures has become increasingly widespread in the United St:ites ’I, In inilt’\\ pensive means for suppressing waves

Mapping of the thermal neutron distribution in the lead block assembly of the PS-211 experiment at CERN, using thermoluminescence and nuclear track detectors.

PubMed

Savvidis, E; Eleftheriadis, C A; Kitis, G

2002-01-01

The main purpose of the TARC (Transmutation by Adiabatic Resonance Crossing) experiment (PS-211), was to demonstrate the possibility to destroy efficiently Long-Lived Fission Fragments (LLFF) in Accelerator Driven Systems (ADS). The experimental set-up which consisted of a lead block with dimensions 3.3 x 3.3 x 3 m3, was installed in a CERN Proton Synchrotron (PS) beam line. The proton beam at 2.5 GeV/c and 3.5 GeV/c, was incident in the centre of the lead block assembly producing neutrons via spallation reactions. In this study, neutron flux measurements are presented in the lead block assembly using thermoluminescence and nuclear track detectors. The results are in good agreement with Monte Carlo calculations as well as with the results of the other methods used in the framework of the TARC experiment.

Ultrasound guided transversus abdominis plane vs surgeon administered intraoperative regional field infiltration with bupivacaine for early postoperative pain control in children undergoing open pyeloplasty.

PubMed

Lorenzo, Armando J; Lynch, Johanne; Matava, Clyde; El-Beheiry, Hossam; Hayes, Jason

2014-07-01

Regional analgesic techniques are commonly used in pediatric urology. Ultrasound guided transversus abdominis plane block has recently gained popularity. However, there is a paucity of information supporting a benefit over regional field infiltration. We present a parallel group, randomized, controlled trial evaluating ultrasound guided transversus abdominis plane block superiority over surgeon delivered regional field infiltration for children undergoing open pyeloplasty at a tertiary referral center. Following ethics board approval and registration, children 0 to 6 years old were recruited and randomized to undergo perioperative transversus abdominis plane block or regional field infiltration for early post-pyeloplasty pain control. General anesthetic delivery, surgical technique and postoperative analgesics were standardized. A blinded assessor regularly captured pain scores in the recovery room using the FLACC (Face, Legs, Activity, Cry, Consolability) scale. The primary outcome was the need for rescue morphine administration based on a FLACC score of 3 or higher. Two pediatric urologists performed 57 pyeloplasties during a 2.5-year period, enrolling 32 children (16 in each group, balanced for age and weight). There were statistically significant differences in the number of children requiring rescue morphine administration (13 of 16 receiving transversus abdominis plane block and 6 of 16 receiving regional field infiltration, p = 0.011), mean ± SD total morphine consumption (0.066 ± 0.051 vs 0.028 ± 0.040 mg/kg, p = 0.021) and mean ± SD pain scores (5 ± 5 vs 2 ± 3, p = 0.043) in the recovery room, in favor of surgeon administered regional field infiltration. No local anesthetic specific adverse events were noted. Ultrasound guided transversus abdominis plane block is not superior to regional field infiltration with bupivacaine as a strategy to minimize early opioid requirements following open pyeloplasty in children. Instead, our data suggest that surgeon delivered regional field infiltration provides better pain control. Copyright © 2014 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Lateral amorphous selenium metal-insulator-semiconductor-insulator-metal photodetectors using ultrathin dielectric blocking layers for dark current suppression

NASA Astrophysics Data System (ADS)

Chang, Cheng-Yi; Pan, Fu-Ming; Lin, Jian-Siang; Yu, Tung-Yuan; Li, Yi-Ming; Chen, Chieh-Yang

2016-12-01

We fabricated amorphous selenium (a-Se) photodetectors with a lateral metal-insulator-semiconductor-insulator-metal (MISIM) device structure. Thermal aluminum oxide, plasma-enhanced chemical vapor deposited silicon nitride, and thermal atomic layer deposited (ALD) aluminum oxide and hafnium oxide (ALD-HfO2) were used as the electron and hole blocking layers of the MISIM photodetectors for dark current suppression. A reduction in the dark current by three orders of magnitude can be achieved at electric fields between 10 and 30 V/μm. The effective dark current suppression is primarily ascribed to electric field lowering in the dielectric layers as a result of charge trapping in deep levels. Photogenerated carriers in the a-Se layer can be transported across the blocking layers to the Al electrodes via Fowler-Nordheim tunneling because a high electric field develops in the ultrathin dielectric layers under illumination. Since the a-Se MISIM photodetectors have a very low dark current without significant degradation in the photoresponse, the signal contrast is greatly improved. The MISIM photodetector with the ALD-HfO2 blocking layer has an optimal signal contrast more than 500 times the contrast of the photodetector without a blocking layer at 15 V/μm.

Entanglement of two blocks of spins in the critical Ising model

NASA Astrophysics Data System (ADS)

Facchi, P.; Florio, G.; Invernizzi, C.; Pascazio, S.

2008-11-01

We compute the entropy of entanglement of two blocks of L spins at a distance d in the ground state of an Ising chain in an external transverse magnetic field. We numerically study the von Neumann entropy for different values of the transverse field. At the critical point we obtain analytical results for blocks of size L=1 and 2. In the general case, the critical entropy is shown to be additive when d→∞ . Finally, based on simple arguments, we derive an expression for the entropy at the critical point as a function of both L and d . This formula is in excellent agreement with numerical results.

Perceptual learning transfer in an appetitive Pavlovian task.

PubMed

Artigas, Antonio A; Prados, Jose

2017-06-01

In two experiments, rats were given intermixed or blocked preexposure to two similar compound stimuli, AX and BX. Following preexposure, conditioning trials took place in which AX (Experiment 1) or a novel compound stimulus NX (Experiment 2) was paired with a food-unconditioned stimulus in an appetitive Pavlovian preparation. Animals that were given alternated preexposure showed lower generalization from AX to BX (Experiment 1) and from NX to a new compound, ZX (Experiment 2), than animals that were given blocked preexposure, a perceptual learning and a perceptual learning transfer effect, respectively.

Do explicit memory manipulations affect the memory blocking effect?

PubMed

Landau, Joshua D; Leynes, P Andrew

2006-01-01

The memory blocking effect (MBE) occurs when people are prevented from completing word fragments because they studied orthographically similar words. Across 3 experiments, we investigated how manipulations that influence explicit memory tasks would influence the MBE. Although a significant MBE was observed in all 3 experiments, manipulating depth of processing (Experiment 1), time to complete the fragments (Experiment 2), and awareness of the MBE (Experiment 3) did not change the magnitude of the MBE. We discuss these results in the context of a suppression mechanism involved in retrieval-induced forgetting.

Nursing Student Perceptions Regarding Simulation Experience Sequencing.

PubMed

Woda, Aimee A; Gruenke, Theresa; Alt-Gehrman, Penny; Hansen, Jamie

2016-09-01

The use of simulated learning experiences (SLEs) have increased within nursing curricula with positive learning outcomes for nursing students. The purpose of this study is to explore nursing students' perceptions of their clinical decision making (CDM) related to the block sequencing of different patient care experiences, SLEs versus hospital-based learning experiences (HLEs). A qualitative descriptive design used open-ended survey questions to generate information about the block sequencing of SLEs and its impact on nursing students' perceived CDM. Three themes emerged from the data: Preexperience Anxiety, Real-Time Decision Making, and Increased Patient Care Experiences. Nursing students identified that having SLEs prior to HLEs provided several benefits. Even when students preferred SLEs prior to HLEs, the sequence did not impact their CDM. This suggests that alternating block sequencing can be used without impacting the students' perceptions of their ability to make decisions. [J Nurs Educ. 2016;55(9):528-532.]. Copyright 2016, SLACK Incorporated.

Practicing Field Hockey Skills Along the Contextual Interference Continuum: A Comparison of Five Practice Schedules

PubMed Central

Cheong, Jadeera Phaik Geok; Lay, Brendan; Grove, J. Robert; Medic, Nikola; Razman, Rizal

2012-01-01

To overcome the weakness of the contextual interference (CI) effect within applied settings, Brady, 2008 recommended that the amount of interference be manipulated. This study investigated the effect of five practice schedules on the learning of three field hockey skills. Fifty-five pre-university students performed a total of 90 trials for each skill under blocked, mixed or random practice orders. Results showed a significant time effect with all five practice conditions leading to improvements in acquisition and learning of the skills. No significant differences were found between the groups. The findings of the present study did not support the CI effect and suggest that either blocked, mixed, or random practice schedules can be used effectively when structuring practice for beginners. Key pointsThe contextual interference effect did not surface when using sport skills.There appears to be no difference between blocked and random practice schedules in the learning of field hockey skills.Low (blocked), moderate (mixed) or high (random) interference practice schedules can be used effectively when conducting a multiple skill practice session for beginners. PMID:24149204

Practicing field hockey skills along the contextual interference continuum: a comparison of five practice schedules.

PubMed

Cheong, Jadeera Phaik Geok; Lay, Brendan; Grove, J Robert; Medic, Nikola; Razman, Rizal

2012-01-01

To overcome the weakness of the contextual interference (CI) effect within applied settings, Brady, 2008 recommended that the amount of interference be manipulated. This study investigated the effect of five practice schedules on the learning of three field hockey skills. Fifty-five pre-university students performed a total of 90 trials for each skill under blocked, mixed or random practice orders. Results showed a significant time effect with all five practice conditions leading to improvements in acquisition and learning of the skills. No significant differences were found between the groups. The findings of the present study did not support the CI effect and suggest that either blocked, mixed, or random practice schedules can be used effectively when structuring practice for beginners. Key pointsThe contextual interference effect did not surface when using sport skills.There appears to be no difference between blocked and random practice schedules in the learning of field hockey skills.Low (blocked), moderate (mixed) or high (random) interference practice schedules can be used effectively when conducting a multiple skill practice session for beginners.

Neural signatures of experimentally induced flow experiences identified in a typical fMRI block design with BOLD imaging

PubMed Central

Keller, Johannes; Grön, Georg

2016-01-01

Previously, experimentally induced flow experiences have been demonstrated with perfusion imaging during activation blocks of 3 min length to accommodate with the putatively slowly evolving “mood” characteristics of flow. Here, we used functional magnetic resonance imaging (fMRI) in a sample of 23 healthy, male participants to investigate flow in the context of a typical fMRI block design with block lengths as short as 30 s. To induce flow, demands of arithmetic tasks were automatically and continuously adjusted to the individual skill level. Compared against conditions of boredom and overload, experience of flow was evident from individuals’ reported subjective experiences and changes in electrodermal activity. Neural activation was relatively increased during flow, particularly in the anterior insula, inferior frontal gyri, basal ganglia and midbrain. Relative activation decreases during flow were observed in medial prefrontal and posterior cingulate cortex, and in the medial temporal lobe including the amygdala. Present findings suggest that even in the context of comparably short activation blocks flow can be reliably experienced and is associated with changes in neural activation of brain regions previously described. Possible mechanisms of interacting brain regions are outlined, awaiting further investigation which should now be possible given the greater temporal resolution compared with previous perfusion imaging. PMID:26508774

Apollo Block I Spacesuit Development and Apollo Block II Spacesuit Competition

NASA Technical Reports Server (NTRS)

McBarron, Jim

2013-01-01

Jim McBarron has over 40 years of experience with the U.S. Air Force pressure suit and NASA spacesuit development and operations. As a result of his experience, he shared his significant knowledge about the requirements and modifications made to the Gemini spacesuit, which were necessary to support the Apollo Block I Program. In addition, he provided an overview of the Apollo Block II Spacesuit competition test program conducted by the NASA Manned Spacecraft Center. Topics covered included the program's chronology; competition test program ground rules, scoring details, and final test results; and the implementation of resulting modifications to the Apollo Spacesuit Program. He concluded his presentation by identifying noteworthy lessons learned.

Assessing potential impacts of energized submarine power cables on crab harvests

NASA Astrophysics Data System (ADS)

Love, Milton S.; Nishimoto, Mary M.; Clark, Scott; McCrea, Merit; Bull, Ann Scarborough

2017-12-01

Offshore renewable energy facilities transmit electricity to shore through submarine power cables. Electromagnetic field emissions (EMFs) are generated from the transmission of electricity through these cables, such as the AC inter-array (between unit) and AC export (to shore) cables often used in offshore energy production. The EMF has both an electric component and a magnetic component. While sheathing can block the direct electric field, the magnetic field is not blocked. A concern raised by fishermen on the Pacific Coast of North America is that commercially important Dungeness crab (Metacarcinus magister Dana, 1852)) might not cross over an energized submarine power cable to enter a baited crab trap, thus potentially reducing their catch. The presence of operating energized cables off southern California and in Puget Sound (cables that are comparable to those within the arrays of existing offshore wind energy devices) allowed us to conduct experiments on how energized power cables might affect the harvesting of both M. magister and another commercially important crab species, Cancer productus Randall, 1839. In this study we tested the questions: 1) Is the catchability of crabs reduced if these animals must traverse an energized power cable to enter a trap and 2) if crabs preferentially do not cross an energized cable, is it the cable structure or the EMF emitted from that cable that deters crabs from crossing? In field experiments off southern California and in Puget Sound, crabs were given a choice of walking over an energized power cable to a baited trap or walking directly away from that cable to a second baited trap. Based on our research we found no evidence that the EMF emitted by energized submarine power cables influenced the catchability of these two species of commercially important crabs. In addition, there was no difference in the crabs' responses to lightly buried versus unburied cables. We did observe that, regardless of the position of the cable, Cancer productus in southern California tended to move to the west and Metacarcinus magister tended to move to the east.

Cell block four exercise yard with original passage to cell ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Cell block four exercise yard with original passage to cell re-exposed, looking from the baseball field, facing west, with scale - Eastern State Penitentiary, 2125 Fairmount Avenue, Philadelphia, Philadelphia County, PA

Millisecond ordering of block-copolymer films via photo-thermal gradients

DOE PAGES

Majewski, Pawel W.; Yager, Kevin G.

2015-03-12

For the promise of self-assembly to be realized, processing techniques must be developed that simultaneously enable control of the nanoscale morphology, rapid assembly, and, ideally, the ability to pattern the nanostructure. Here, we demonstrate how photo-thermal gradients can be used to control the ordering of block-copolymer thin films. Highly localized laser heating leads to intense thermal gradients, which induce a thermophoretic force on morphological defects. This increases the ordering kinetics by at least 3 orders-of-magnitude, compared to conventional oven annealing. By simultaneously exploiting the thermal gradients to induce shear fields, we demonstrate uniaxial alignment of a block-copolymer film in lessmore » than a second. Finally, we provide examples of how control of the incident light-field can be used to generate prescribed configurations of block-copolymer nanoscale patterns.« less

Laser Generated Magnetic Fields

DTIC Science & Technology

1976-06-01

30, II dttlormnt from Rmpori) IS. SUPPLEMENTARY NOTES 19. KEY WORDS (Continue on tororoo aldo II nocoommry and Idontlty by block nuaibar) Crater...dependence of laser generated magnetic fields Laser crater cross-sections X-ray detection from laser plasma 20. ABSTRACT (Contlmio on tovormo aid* II...nacaaaary and Idontlty ay block mmtbor) A sequence of laser pulses focussed onto the same spot on a target produces evaporation of target material and the

Electrical control of superparamagnetism

NASA Astrophysics Data System (ADS)

Yamada, Kihiro T.; Koyama, Tomohiro; Kakizakai, Haruka; Miwa, Kazumoto; Ando, Fuyuki; Ishibashi, Mio; Kim, Kab-Jin; Moriyama, Takahiro; Ono, Shimpei; Chiba, Daichi; Ono, Teruo

2017-01-01

The electric field control of superparamagnetism is realized using a Cu/Ni system, in which the deposited Ni shows superparamagnetic behavior above the blocking temperature. An electric double-layer capacitor (EDLC) with the Cu/Ni electrode and a nonmagnetic counter electrode is fabricated to examine the electric field effect on magnetism in the magnetic electrode. By changing the voltage applied to the EDLC, the blocking temperature of the system is clearly modulated.

Evolution of Friction, Wear, and Seismic Radiation Along Experimental Bi-material Faults

NASA Astrophysics Data System (ADS)

Carpenter, B. M.; Zu, X.; Shadoan, T.; Self, A.; Reches, Z.

2017-12-01

Faults are commonly composed by rocks of different lithologies and mechanical properties that are positioned against one another by fault slip; such faults are referred to as bimaterial-faults (BF). We investigate the mechanical behavior, wear production, and seismic radiation of BF via laboratory experiments on a rotary shear apparatus. In the experiments, two rock blocks of dissimilar or similar lithology are sheared against each other. We used contrasting rock pairs of a stiff, igneous block (diorite, granite, or gabbro) against a more compliant, sedimentary block (sandstone, limestone, or dolomite). The cylindrical blocks have a ring-shaped contact, and are loaded under conditions of constant normal stress and shear velocity. Fault behavior was monitored with stress, velocity and dilation sensors. Acoustic activity is monitored with four 3D accelerometers mounted at 2 cm distance from the experimental fault. These sensors can measure accelerations up to 500 g, and their full waveform output is recorded at 1MHz for periods up to 14 sec. Our preliminary results indicate that the bi-material nature of the fault has a strong affect on slip initiation, wear evolution, and acoustic emission activity. In terms of wear, we observe enhanced wear in experiments with a sandstone block sheared against a gabbro or limestone block. Experiments with a limestone or sandstone block produced distinct slickenline striations. Further, significant differences appeared in the number and amplitude of acoustic events depending on the bi-material setting and slip-distance. A gabbro-gabbro fault showed a decrease in both amplitude and number of acoustic events with increasing slip. Conversely, a gabbro-limestone fault showed a decrease in the number of events, but an increase in average event amplitude. Ongoing work focuses on advanced characterization of mechanical, dynamic weakening, and acoustic, frequency content, parameters.

Block Play: It's Not Just for Boys Anymore--Strategies for Encouraging Girls' Block Play

ERIC Educational Resources Information Center

Tokarz, Barb

2008-01-01

While block play is essential for both boys' and girls' social, cognitive, language, and motor development, girls do not engage in block play as frequently as boys. This situation can be attributed to the socialization process--children learn societal expectations for behavior and materials for both boys and girls--lack of experience for girls…

Failures to replicate blocking are surprising and informative-Reply to Soto (2018).

PubMed

Maes, Elisa; Krypotos, Angelos-Miltiadis; Boddez, Yannick; Alfei Palloni, Joaquín Matías; D'Hooge, Rudi; De Houwer, Jan; Beckers, Tom

2018-04-01

The blocking effect has inspired numerous associative learning theories and is widely cited in the literature. We recently reported a series of 15 experiments that failed to obtain a blocking effect in rodents. On the basis of those consistent failures, we claimed that there is a lack of insight into the boundary conditions for blocking. In his commentary, Soto (2018) argued that contemporary associative learning theory does provide a specific boundary condition for the occurrence of blocking, namely the use of same- versus different-modality stimuli. Given that in 10 of our 15 experiments same-modality stimuli were used, he claims that our failure to observe a blocking effect is unsurprising. We disagree with that claim, because of theoretical, empirical, and statistical problems with his analysis. We also address 2 other possible reasons for a lack of blocking that are referred to in Soto's (2018) analysis, related to generalization and salience, and dissect the potential importance of both. Although Soto's (2018) analyses raise a number of interesting points, we see more merit in an empirically guided analysis and call for empirical testing of boundary conditions on blocking. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

John H. Dillon Medal Lecture: Magnetic Field Directed Self-Assembly of Block Copolymers and Surfactant Mesophases

NASA Astrophysics Data System (ADS)

Osuji, Chinedum

2015-03-01

Molecular self-assembly of block copolymers and small molecule surfactants gives rise to a rich phase behavior as a function of temperature, composition, and other variables. We consider the directed self-assembly of such soft mesophases using magnetic fields, principally through the use of in situ x-ray scattering studies. Field alignment is predicated on a sufficiently large product of magnetic anisotropy and grain size to produce magnetostatic interactions which are substantive relative to thermal forces. We examine the role of field strength on the phase behavior and alignment dynamics of a series of soft mesophases, outlining the possibility to readily create highly ordered functional materials over macroscopic length scales. We show that magnetic fields as large as 10 T have little discernable impact on the stability of block copolymer systems considered, with shifts in order-disorder transition temperatures of roughly 5 mK or smaller. Consequently, directed self-assembly in these systems proceeds by nucleation of randomly aligned grains which thereafter rotate into registry with the field. We highlight the tradeoff between decreasing mobility and increasing anisotropic field interaction that dictates alignment kinetics while transiting from a high temperature disordered state to an ordered system at lower temperatures. NSF support through DMR-0847534 is gratefully acknowledged.

Glass Polarization Induced Drift of a Closed-Loop Micro-Accelerometer.

PubMed

Zhou, Wu; He, Jiangbo; Yu, Huijun; Peng, Bei; He, Xiaoping

2018-01-20

The glass polarization effects were introduced in this paper to study the main cause of turn-on drift phenomenon of closed-loop micro-accelerometers. The glass substrate underneath the sensitive silicon structure underwent a polarizing process when the DC bias voltage was applied. The slow polarizing process induced an additional electrostatic field to continually drag the movable mass block from one position to another so that the sensing capacitance was changed, which led to an output drift of micro-accelerometers. This drift was indirectly tested by experiments and could be sharply reduced by a shielding layer deposited on the glass substrate because the extra electrical filed was prohibited from generating extra electrostatic forces on the movable fingers of the mass block. The experimental results indicate the average magnitude of drift decreased about 73%, from 3.69 to 0.99 mV. The conclusions proposed in this paper showed a meaningful guideline to improve the stability of micro-devices based on silicon-on-glass structures.

Glass Polarization Induced Drift of a Closed-Loop Micro-Accelerometer

PubMed Central

He, Jiangbo; Yu, Huijun; Peng, Bei; He, Xiaoping

2018-01-01

The glass polarization effects were introduced in this paper to study the main cause of turn-on drift phenomenon of closed-loop micro-accelerometers. The glass substrate underneath the sensitive silicon structure underwent a polarizing process when the DC bias voltage was applied. The slow polarizing process induced an additional electrostatic field to continually drag the movable mass block from one position to another so that the sensing capacitance was changed, which led to an output drift of micro-accelerometers. This drift was indirectly tested by experiments and could be sharply reduced by a shielding layer deposited on the glass substrate because the extra electrical filed was prohibited from generating extra electrostatic forces on the movable fingers of the mass block. The experimental results indicate the average magnitude of drift decreased about 73%, from 3.69 to 0.99 mV. The conclusions proposed in this paper showed a meaningful guideline to improve the stability of micro-devices based on silicon-on-glass structures. PMID:29361685

A heat flux modulator from carbon nanotubes.

PubMed

Jiang, Shaohui; Zhang, Guang; Xia, Dan; Liu, Changhong; Fan, Shoushan

2015-08-28

For a heat flux modulator, the most difficult problem is that the main carriers named 'phonons' have little response to external fields. Of the existing studies on heat flux modulators, most were theoretical work and the materials systems for the theoretical calculations were artificial lattices. In this paper, we made a heat modulator with ultrathin buckypaper which was made of multi-layer carbon nanotube sheets overlapped together, and achieved an on/off ratio whose value was 1.41 using an pendent block in experiments without special optimizations. When the temperatures of the two sides were of appropriate values, we could even see a negative heat flux. Intuitively, the heat flux was tuned by the gap between the buckypaper and the pendent gate, and we observed that there was heat transferred to the pendent block. The structure of the modulator is similar to a CNT transistor with a contactless gate, hence this type of micromodulator will be easy to manufacture in the future.

Context Blocking in Rat Autoshaping: Sign-Tracking versus Goal-Tracking

ERIC Educational Resources Information Center

Costa, Daniel S. J.; Boakes, Robert A.

2009-01-01

Prior experience of unsignaled food can interfere with subsequent acquisition by birds of autoshaped key-pecking at a signal light. This has been understood to indicate that unsignaled food results in context conditioning, which blocks subsequent learning about the keylight-food relationship. In the present experiment with rats lever insertion as…

Control of Rock Mechanics in Underground Ore Mining

NASA Astrophysics Data System (ADS)

Golik, V. I.; Efremenkov, A. B.

2017-07-01

Performance indicators in underground mining of thick iron fields can be insufficient since geo-mechanic specifics of ore-hosting fields might be considered inadequately, as a consequence, critical deformations and even earth’s surface destruction are possible, lowering the indicators of full subsurface use, this way. The reason for it is the available approach to estimating the performance of mining according to ore excavation costs, without assessing losses of valuable components and damage to the environment. The experimental approach to the problem is based on a combination of methods to justify technical capability and performance of mining technology improvement with regard to geomechanical factors. The main idea of decisions to be taken is turning geo-materials into the condition of triaxial compression via developing the support constructions of blocked up structural rock block. The study was carried out according to an integrated approach based on the analysis of concepts, field observations, and simulation with the photo-elastic materials in conditions of North Caucasus deposits. A database containing information on the deposit can be developed with the help of industrial experiments and performance indicators of the field can be also improved using the ability of ore-hosting fields to develop support constructions, keeping the geo-mechanical stability of the system at lower cost, avoiding ore contamination at the processing stage. The proposed model is a specific one because an adjustment coefficient of natural and anthropogenic stresses is used and can be adopted for local conditions. The relation of natural to anthropogenic factors can make more precise the standards of developed, prepared and ready to excavation ore reserves relying on computational methods. It is possible to minimize critical stresses and corresponding deformations due to dividing the ore field into sectors safe from the standpoint of geo-mechanics, and using less cost-demanding ways of keeping rock massif stable.

Entanglement and Metrology with Singlet-Triplet Qubits

NASA Astrophysics Data System (ADS)

Shulman, Michael Dean

Electron spins confined in semiconductor quantum dots are emerging as a promising system to study quantum information science and to perform sensitive metrology. Their weak interaction with the environment leads to long coherence times and robust storage for quantum information, and the intrinsic tunability of semiconductors allows for controllable operations, initialization, and readout of their quantum state. These spin qubits are also promising candidates for the building block for a scalable quantum information processor due to their prospects for scalability and miniaturization. However, several obstacles limit the performance of quantum information experiments in these systems. For example, the weak coupling to the environment makes inter-qubit operations challenging, and a fluctuating nuclear magnetic field limits the performance of single-qubit operations. The focus of this thesis will be several experiments which address some of the outstanding problems in semiconductor spin qubits, in particular, singlet-triplet (S-T0) qubits. We use these qubits to probe both the electric field and magnetic field noise that limit the performance of these qubits. The magnetic noise bath is probed with high bandwidth and precision using novel techniques borrowed from the field of Hamiltonian learning, which are effective due to the rapid control and readout available in S-T 0 qubits. These findings allow us to effectively undo the undesired effects of the fluctuating nuclear magnetic field by tracking them in real-time, and we demonstrate a 30-fold improvement in the coherence time T2*. We probe the voltage noise environment of the qubit using coherent qubit oscillations, which is partially enabled by control of the nuclear magnetic field. We find that the voltage noise bath is frequency-dependent, even at frequencies as high as 1MHz, and it shows surprising and, as of yet, unexplained temperature dependence. We leverage this knowledge of the voltage noise environment, the nuclear magnetic field control, as well as new techniques for calibrated measurement of the density matrix in a singlet-triplet qubit to entangle two adjacent single-triplet qubits. We fully characterize the generated entangled states and prove that they are, indeed, entangled. This work opens new opportunities to use qubits as sensors for improved metrological capabilities, as well as for improved quantum information processing. The singlet-triplet qubit is unique in that it can be used to probe two fundamentally different noise baths, which are important for a large variety of solid state qubits. More specifically, this work establishes the singlet-triplet qubit as a viable candidate for the building block of a scalable quantum information processor.

Cortical sources of ERP in prosaccade and antisaccade eye movements using realistic source models

PubMed Central

Richards, John E.

2013-01-01

The cortical sources of event-related-potentials (ERP) using realistic source models were examined in a prosaccade and antisaccade procedure. College-age participants were presented with a preparatory interval and a target that indicated the direction of the eye movement that was to be made. In some blocks a cue was given in the peripheral location where the target was to be presented and in other blocks no cue was given. In Experiment 1 the prosaccade and antisaccade trials were presented randomly within a block; in Experiment 2 procedures were compared in which either prosaccade and antisaccade trials were mixed in the same block, or trials were presented in separate blocks with only one type of eye movement. There was a central negative slow wave occurring prior to the target, a slow positive wave over the parietal scalp prior to the saccade, and a parietal spike potential immediately prior to saccade onset. Cortical source analysis of these ERP components showed a common set of sources in the ventral anterior cingulate and orbital frontal gyrus for the presaccadic positive slow wave and the spike potential. In Experiment 2 the same cued- and non-cued blocks were used, but prosaccade and antisaccade trials were presented in separate blocks. This resulted in a smaller difference in reaction time between prosaccade and antisaccade trials. Unlike the first experiment, the central negative slow wave was larger on antisaccade than on prosaccade trials, and this effect on the ERP component had its cortical source primarily in the parietal and mid-central cortical areas contralateral to the direction of the eye movement. These results suggest that blocked prosaccade and antisaccade trials results in preparatory or set effects that decreases reaction time, eliminates some cueing effects, and is based on contralateral parietal-central brain areas. PMID:23847476

Magnetic hierarchical deposition

NASA Astrophysics Data System (ADS)

Posazhennikova, Anna I.; Indekeu, Joseph O.

2014-11-01

We consider random deposition of debris or blocks on a line, with block sizes following a rigorous hierarchy: the linear size equals 1/λn in generation n, in terms of a rescaling factor λ. Without interactions between the blocks, this model is described by a logarithmic fractal, studied previously, which is characterized by a constant increment of the length, area or volume upon proliferation. We study to what extent the logarithmic fractality survives, if each block is equipped with an Ising (pseudo-)spin s=±1 and the interactions between those spins are switched on (ranging from antiferromagnetic to ferromagnetic). It turns out that the dependence of the surface topology on the interaction sign and strength is not trivial. For instance, deep in the ferromagnetic regime, our numerical experiments and analytical results reveal a sharp crossover from a Euclidean transient, consisting of aggregated domains of aligned spins, to an asymptotic logarithmic fractal growth. In contrast, deep into the antiferromagnetic regime the surface roughness is important and is shown analytically to be controlled by vacancies induced by frustrated spins. Finally, in the weak interaction regime, we demonstrate that the non-interacting model is extremal in the sense that the effect of the introduction of interactions is only quadratic in the magnetic coupling strength. In all regimes, we demonstrate the adequacy of a mean-field approximation whenever vacancies are rare. In sum, the logarithmic fractal character is robust with respect to the introduction of spatial correlations in the hierarchical deposition process.

Uranium bioreduction rates across scales: biogeochemical hot moments and hot spots during a biostimulation experiment at Rifle, Colorado.

PubMed

Bao, Chen; Wu, Hongfei; Li, Li; Newcomer, Darrell; Long, Philip E; Williams, Kenneth H

2014-09-02

We aim to understand the scale-dependent evolution of uranium bioreduction during a field experiment at a former uranium mill site near Rifle, Colorado. Acetate was injected to stimulate Fe-reducing bacteria (FeRB) and to immobilize aqueous U(VI) to insoluble U(IV). Bicarbonate was coinjected in half of the domain to mobilize sorbed U(VI). We used reactive transport modeling to integrate hydraulic and geochemical data and to quantify rates at the grid block (0.25 m) and experimental field scale (tens of meters). Although local rates varied by orders of magnitude in conjunction with biostimulation fronts propagating downstream, field-scale rates were dominated by those orders of magnitude higher rates at a few selected hot spots where Fe(III), U(VI), and FeRB were at their maxima in the vicinity of the injection wells. At particular locations, the hot moments with maximum rates negatively corresponded to their distance from the injection wells. Although bicarbonate injection enhanced local rates near the injection wells by a maximum of 39.4%, its effect at the field scale was limited to a maximum of 10.0%. We propose a rate-versus-measurement-length relationship (log R' = -0.63 log L - 2.20, with R' in μmol/mg cell protein/day and L in meters) for orders-of-magnitude estimation of uranium bioreduction rates across scales.

Tsunamis generated by subaerial mass flows

USGS Publications Warehouse

Walder, S.J.; Watts, P.; Sorensen, O.E.; Janssen, K.

2003-01-01

Tsunamis generated in lakes and reservoirs by subaerial mass flows pose distinctive problems for hazards assessment because the domain of interest is commonly the "near field," beyond the zone of complex splashing but close enough to the source that wave propagation effects are not predominant. Scaling analysis of the equations governing water wave propagation shows that near-field wave amplitude and wavelength should depend on certain measures of mass flow dynamics and volume. The scaling analysis motivates a successful collapse (in dimensionless space) of data from two distinct sets of experiments with solid block "wave makers." To first order, wave amplitude/water depth is a simple function of the ratio of dimensionless wave maker travel time to dimensionless wave maker volume per unit width. Wave amplitude data from previous laboratory investigations with both rigid and deformable wave makers follow the same trend in dimensionless parameter space as our own data. The characteristic wavelength/water depth for all our experiments is simply proportional to dimensionless wave maker travel time, which is itself given approximately by a simple function of wave maker length/water depth. Wave maker shape and rigidity do not otherwise influence wave features. Application of the amplitude scaling relation to several historical events yields "predicted" near-field wave amplitudes in reasonable agreement with measurements and observations. Together, the scaling relations for near-field amplitude, wavelength, and submerged travel time provide key inputs necessary for computational wave propagation and hazards assessment.

Selective Absorption Mechanism for the Maintenance of Blocking

NASA Astrophysics Data System (ADS)

Yamazaki, Akira; Itoh, Hisanori

2010-05-01

Atmospheric blocking is one of the most influential phenomena in global atmospheric environments. The understanding of its dynamical processes is important to clarify weather extremes and the stratosphere-troposphere coupling and to extend forecast periods. In the dynamics of blocking, especially, its maintenance mechanism has been a stimulating topic for many meteorologists. About the maintenance mechanism of blocking, Shutts (1983) evaluated the effect of synoptic eddies in his numerical model and proposed the Eddy Straining Mechanism (hereafter, referred to as ESM). Using simple numerical models, he demonstrated that synoptic eddies strained in the north-south direction by blocking provide negative/positive vorticity to a blocking high/low and this vorticity forcing, i.e., the second-order flow maintains the blocking dipole structure against dissipation. Some pieces of evidence, however have shown that the ESM does not work well in several real cases of the block maintenance. For example, Arai and Mukougawa (2002) performed a similar experiment to Shutts (1983) and indicated the strong sensitivity of the ESM against a small meridional shift of the stormtrack (strictly speaking, wavemaker), or a small change of the size of high-frequency eddies. This is a very adverse constraint in the real atmosphere because the relative positions of blocking to the stormtrack tend to fluctuate from case to case so that they do not necessarily exist in the same latitude band. Thus, we propose a more realistic mechanism of the block maintenance named as the Selective Absorption Mechanism (hereafter referred to as SAM), in which a blocking anticyclone selectively and exclusively absorbs synoptic anticyclones. This mechanism is essentially the same mechanism as the Fujiwhara effect, which qualitatively explains that binary eddies with the same polarity merge and eddies with the opposite polarity separate. In this study, we verify the effectiveness of the SAM by observational analyses and simple numerical experiments. Ten episodes of blocking that occurred in the mid-North Pacific and the eastern North Atlantic between 1990 and 2005 are investigated. Trajectories of synoptic anticyclones and cyclones during blocking persistent periods are analyzed and show the selective absorption of anticyclonic eddies by the blocking highs. We also perform numerical experiments using the nonlinear barotropic vorticity equation on a beta-plane channel. The maintenance rate of blocking is quantitatively evaluated by using an areal averaged method. The result supports the block maintenance by the SAM. From the above two results, we can conclude that the SAM is more adaptive as the block maintenance mechanism than the ESM, because the essence of the SAM is absorption of eddies, not but eddy straining.

Blocking Mimicry Makes True and False Smiles Look the Same

PubMed Central

Rychlowska, Magdalena; Cañadas, Elena; Wood, Adrienne; Krumhuber, Eva G.; Fischer, Agneta; Niedenthal, Paula M.

2014-01-01

Recent research suggests that facial mimicry underlies accurate interpretation of subtle facial expressions. In three experiments, we manipulated mimicry and tested its role in judgments of the genuineness of true and false smiles. Experiment 1 used facial EMG to show that a new mouthguard technique for blocking mimicry modifies both the amount and the time course of facial reactions. In Experiments 2 and 3, participants rated true and false smiles either while wearing mouthguards or when allowed to freely mimic the smiles with or without additional distraction, namely holding a squeeze ball or wearing a finger-cuff heart rate monitor. Results showed that blocking mimicry compromised the decoding of true and false smiles such that they were judged as equally genuine. Together the experiments highlight the role of facial mimicry in judging subtle meanings of facial expressions. PMID:24670316

Verapamil protective effect on natural and artificial magnetic field cardiovascular impact.

PubMed

Gmitrov, Juraj; Ohkubo, Chiyoji

2002-10-01

Previously we found an opposite effect of artificial static magnetic field (SMF) and natural geomagnetic field (GMF) on arterial baroreceptors. A 0.35 T SMF increased baroreflex sensitivity (BRS), whereas GMF disturbance decreased BRS. Here, we investigated interrelated impacts on arterial baroreceptors of 0.35 T SMF, generated by Nd(2)-Fe(14)-B alloy magnets, GMF, and verapamil, a Ca(2+) channel blocking agent. We measured BRS in rabbits before and after local SMF exposure of sinocarotid baroreceptors or after simultaneous SMF and verapamil application, in conjunction with geomagnetic disturbance during actual experimental run (determined by K-index) and geomagnetic disturbance over the preceding 24 h of each experiment (A(k)-index). BRS was estimated from peak responses of mean arterial pressure (MAP) and heart rate, expressed as percentages of the resting values preceding each pair of pressure (phenylephrine) and depressor drug (nitroprusside) injections. Prior to verapamil and/or SMF application we found a significant positive correlation of K-index with MAP (t = 2.39, P =.021, n = 44), but negative with BRS (t = -4.60, P =.0003, n = 44), and found a negative correlation of A(k)-index with BRS (t = -2.7, P = 0.01, n = 44). SMF induced an increase in BRS (0.79 +/- 0.1 vs. 1.15 +/- 0.1 bpm%/mmHg%, initial value vs. SMF exposure, P <.0002, n = 26). Verapamil infusion blocked the SMF and GMF effect on BRS, indicating Ca(2+) channels as a possible site of both fields' impact. SMF and GMF probably affect baroreceptor sensory transduction, modulating baroreceptor membranes' Ca(2+) channel permeability. Copyright 2002 Wiley-Liss, Inc.

Effect of mungbean (Vigna radiate) living mulch on density and dry weight of weeds in corn (Zea mays) field.

PubMed

Moghadam, M Bakhtiari; Vazan, S; Darvishi, B; Golzardi, F; Farahani, M Esfini

2011-01-01

Living mulch is a suitable solution for weeds ecological management and is considered as an effective method in decreasing of weeds density and dry weight. In order to evaluate of mungbean living mulch effect on density and dry weight of weeds in corn field, an experiment was conducted as a split plot based on randomized complete block design with four blocks in Research Field of Department of Agronomy, Karaj Branch, Islamic Azad University in 2010. Main plots were time of mungbean suppression with 2,4-D herbicide in four levels (4, 6, 8 and 10 leaves stages of corn) and control without weeding and sub plots were densities of mungbean in three levels (50%, 100% and 150% more than optimum density). Density and dry weight of the weeds were measured in all plots with a quadrate (60 x 100 cm) in 10 days after tasseling. Totally, 9 species of weeds were identified in the field, which included 4 broad leave species that were existed in all plots. The results showed that the best time for suppression of mungbean is the 8 leaves stage of corn, which decreased density and dry weight of weeds, 53% and 51% in comparison with control, respectively. Increase of density of mungbean from 50% into 150% more than optimum density, decrease the density and dry weight of weeds, 27.5% and 22%, respectively. It is concluded that the best time and density for suppression mungbean was 8 leaves stage of corn, and 150% more than optimum density, which decreased density and dry weight of the weeds 69% and 63.5% in comparison with control, respectively.

Charge transport model in solid-state avalanche amorphous selenium and defect suppression design

NASA Astrophysics Data System (ADS)

Scheuermann, James R.; Miranda, Yesenia; Liu, Hongyu; Zhao, Wei

2016-01-01

Avalanche amorphous selenium (a-Se) in a layer of High Gain Avalanche Rushing Photoconductor (HARP) is being investigated for its use in large area medical imagers. Avalanche multiplication of photogenerated charge requires electric fields greater than 70 V μm-1. For a-Se to withstand this high electric field, blocking layers are used to prevent the injection of charge carriers from the electrodes. Blocking layers must have a high injection barrier and deep trapping states to reduce the electric field at the interface. In the presence of a defect in the blocking layer, a distributed resistive layer (DRL) must be included into the structure to build up space charge and reduce the electric field in a-Se and the defect. A numerical charge transport model has been developed to optimize the properties of blocking layers used in various HARP structures. The model shows the incorporation of a DRL functionality into the p-layer can reduce dark current at a point defect by two orders of magnitude by reducing the field in a-Se to the avalanche threshold. Hole mobility in a DRL of ˜10-8 cm2 V-1 s-1 at 100 V μm-1 as demonstrated by the model can be achieved experimentally by varying the hole mobility of p-type organic or inorganic semiconductors through doping, e.g., using Poly(9-vinylcarbozole) doped with 1%-3% (by weight) of poly(3-hexylthiopene).

Calibration and validation of rockfall models

NASA Astrophysics Data System (ADS)

Frattini, Paolo; Valagussa, Andrea; Zenoni, Stefania; Crosta, Giovanni B.

2013-04-01

Calibrating and validating landslide models is extremely difficult due to the particular characteristic of landslides: limited recurrence in time, relatively low frequency of the events, short durability of post-event traces, poor availability of continuous monitoring data, especially for small landslide and rockfalls. For this reason, most of the rockfall models presented in literature completely lack calibration and validation of the results. In this contribution, we explore different strategies for rockfall model calibration and validation starting from both an historical event and a full-scale field test. The event occurred in 2012 in Courmayeur (Western Alps, Italy), and caused serious damages to quarrying facilities. This event has been studied soon after the occurrence through a field campaign aimed at mapping the blocks arrested along the slope, the shape and location of the detachment area, and the traces of scars associated to impacts of blocks on the slope. The full-scale field test was performed by Geovert Ltd in the Christchurch area (New Zealand) after the 2011 earthquake. During the test, a number of large blocks have been mobilized from the upper part of the slope and filmed with high velocity cameras from different viewpoints. The movies of each released block were analysed to identify the block shape, the propagation path, the location of impacts, the height of the trajectory and the velocity of the block along the path. Both calibration and validation of rockfall models should be based on the optimization of the agreement between the actual trajectories or location of arrested blocks and the simulated ones. A measure that describe this agreement is therefore needed. For calibration purpose, this measure should simple enough to allow trial and error repetitions of the model for parameter optimization. In this contribution we explore different calibration/validation measures: (1) the percentage of simulated blocks arresting within a buffer of the actual blocks, (2) the percentage of trajectories passing through the buffer of the actual rockfall path, (3) the mean distance between the location of arrest of each simulated blocks and the location of the nearest actual blocks; (4) the mean distance between the location of detachment of each simulated block and the location of detachment of the actual block located closer to the arrest position. By applying the four measures to the case studies, we observed that all measures are able to represent the model performance for validation purposes. However, the third measure is more simple and reliable than the others, and seems to be optimal for model calibration, especially when using a parameter estimation and optimization modelling software for automated calibration.

Encoders for block-circulant LDPC codes

NASA Technical Reports Server (NTRS)

Andrews, Kenneth; Dolinar, Sam; Thorpe, Jeremy

2005-01-01

In this paper, we present two encoding methods for block-circulant LDPC codes. The first is an iterative encoding method based on the erasure decoding algorithm, and the computations required are well organized due to the block-circulant structure of the parity check matrix. The second method uses block-circulant generator matrices, and the encoders are very similar to those for recursive convolutional codes. Some encoders of the second type have been implemented in a small Field Programmable Gate Array (FPGA) and operate at 100 Msymbols/second.

Method of making high breakdown voltage semiconductor device

DOEpatents

Arthur, Stephen D.; Temple, Victor A. K.

1990-01-01

A semiconductor device having at least one P-N junction and a multiple-zone junction termination extension (JTE) region which uniformly merges with the reverse blocking junction is disclosed. The blocking junction is graded into multiple zones of lower concentration dopant adjacent termination to facilitate merging of the JTE to the blocking junction and placing of the JTE at or near the high field point of the blocking junction. Preferably, the JTE region substantially overlaps the graded blocking junction region. A novel device fabrication method is also provided which eliminates the prior art step of separately diffusing the JTE region.

Inverse random source scattering for the Helmholtz equation in inhomogeneous media

NASA Astrophysics Data System (ADS)

Li, Ming; Chen, Chuchu; Li, Peijun

2018-01-01

This paper is concerned with an inverse random source scattering problem in an inhomogeneous background medium. The wave propagation is modeled by the stochastic Helmholtz equation with the source driven by additive white noise. The goal is to reconstruct the statistical properties of the random source such as the mean and variance from the boundary measurement of the radiated random wave field at multiple frequencies. Both the direct and inverse problems are considered. We show that the direct problem has a unique mild solution by a constructive proof. For the inverse problem, we derive Fredholm integral equations, which connect the boundary measurement of the radiated wave field with the unknown source function. A regularized block Kaczmarz method is developed to solve the ill-posed integral equations. Numerical experiments are included to demonstrate the effectiveness of the proposed method.

The role of experience in location estimation: Target distributions shift location memory biases.

PubMed

Lipinski, John; Simmering, Vanessa R; Johnson, Jeffrey S; Spencer, John P

2010-04-01

Research based on the Category Adjustment model concluded that the spatial distribution of target locations does not influence location estimation responses [Huttenlocher, J., Hedges, L., Corrigan, B., & Crawford, L. E. (2004). Spatial categories and the estimation of location. Cognition, 93, 75-97]. This conflicts with earlier results showing that location estimation is biased relative to the spatial distribution of targets [Spencer, J. P., & Hund, A. M. (2002). Prototypes and particulars: Geometric and experience-dependent spatial categories. Journal of Experimental Psychology: General, 131, 16-37]. Here, we resolve this controversy by using a task based on Huttenlocher et al. (Experiment 4) with minor modifications to enhance our ability to detect experience-dependent effects. Results after the first block of trials replicate the pattern reported in Huttenlocher et al. After additional experience, however, participants showed biases that significantly shifted according to the target distributions. These results are consistent with the Dynamic Field Theory, an alternative theory of spatial cognition that integrates long-term memory traces across trials relative to the perceived structure of the task space. Copyright 2009 Elsevier B.V. All rights reserved.

Colloidal polymers with controlled sequence and branching constructed from magnetic field assembled nanoparticles.

PubMed

Bannwarth, Markus B; Utech, Stefanie; Ebert, Sandro; Weitz, David A; Crespy, Daniel; Landfester, Katharina

2015-03-24

The assembly of nanoparticles into polymer-like architectures is challenging and usually requires highly defined colloidal building blocks. Here, we show that the broad size-distribution of a simple dispersion of magnetic nanocolloids can be exploited to obtain various polymer-like architectures. The particles are assembled under an external magnetic field and permanently linked by thermal sintering. The remarkable variety of polymer-analogue architectures that arises from this simple process ranges from statistical and block copolymer-like sequencing to branched chains and networks. This library of architectures can be realized by controlling the sequencing of the particles and the junction points via a size-dependent self-assembly of the single building blocks.

EqualWrites: Reducing Intra-set Write Variations for Enhancing Lifetime of Non-volatile Caches

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

Mittal, Sparsh; Vetter, Jeffrey S.

Driven by the trends of increasing core-count and bandwidth-wall problem, the size of last level caches (LLCs) has greatly increased and hence, the researchers have explored non-volatile memories (NVMs) which provide high density and consume low-leakage power. Since NVMs have low write-endurance and the existing cache management policies are write variation-unaware, effective wear-leveling techniques are required for achieving reasonable cache lifetimes using NVMs. We present EqualWrites, a technique for mitigating intra-set write variation. In this paper, our technique works by recording the number of writes on a block and changing the cache-block location of a hot data-item to redirect themore » future writes to a cold block to achieve wear-leveling. Simulation experiments have been performed using an x86-64 simulator and benchmarks from SPEC06 and HPC (high-performance computing) field. The results show that for single, dual and quad-core system configurations, EqualWrites improves cache lifetime by 6.31X, 8.74X and 10.54X, respectively. In addition, its implementation overhead is very small and it provides larger improvement in lifetime than three other intra-set wear-leveling techniques and a cache replacement policy.« less

Locking mechanisms in degree-4 vertex origami structures

NASA Astrophysics Data System (ADS)

Fang, Hongbin; Li, Suyi; Xu, Jian; Wang, K. W.

2016-04-01

Origami has emerged as a potential tool for the design of mechanical metamaterials and metastructures whose novel properties originate from their crease patterns. Most of the attention in origami engineering has focused on the wellknown Miura-Ori, a folded tessellation that is flat-foldable for folded sheet and stacked blocks. This study advances the state of the art and expands the research field to investigate generic degree-4 vertex (4-vertex) origami, with a focus on facet-binding. In order to understand how facet-binding attributes to the mechanical properties of 4-vertex origami structures, geometries of the 4-vertex origami cells are analyzed and analytically expressed. Through repeating and stacking 4-vertex cells, origami sheets and stacked origami blocks can be constructed. Geometry analyses discover four mechanisms that will lead to the self-locking of 4-vertex origami cells, sheets, and stacked blocks: in-cell facet-binding, inlayer facet-binding, inter-layer facet binding, and in-layer and inter-layer facet-bindings. These mechanisms and the predicted self-locking phenomena are verified through 3D simulations and prototype experiments. Finally, this paper briefly introduces the unusual mechanical properties caused by the locking of 4-vertex origami structures. The research reported in this paper could foster a new breed of self-locking structures with various engineering applications.

Effect of Summon Preferred Food Source on feeding, tunneling, and bait station discovery by the formosan subterranean termite (Isoptera: Rhinotermitidae).

PubMed

Cornelius, Mary L; Lax, Alan R

2005-04-01

This study evaluated the effect of Summon Preferred Food Source on feeding, tunneling, and bait station discovery by the Formosan subterranean termite, Coptotermes formosanus Shiraki. Bioassays were conducted to determine whether Summon disks affected the aggregation and feeding behavior of termites and to determine whether the presence of Summon disks caused increased recruitment of termites to wood blocks. When termites encountered the disk, they immediately clustered on top of the disk. Termites were observed aggregating on top of the disk throughout the experiment. Consumption of Summon disks was significantly greater than consumption of cardboard disks in paired choice tests. The presence of a Summon disk on top of a wood block caused a significant increase in consumption of the wood block. Bioassays also were conducted to determine whether water extracts of Summon disks affected termite behavior. Consumption of filter paper disks treated with a water extract of Summon disks was significantly greater than consumption of control filter paper disks. Termites tunneled through sand treated with a water extract of Summon disks faster than they tunneled through untreated sand. In a field test, the rate of infestation of monitoring stations with a Summon disk was 3 times greater than the rate of infestations of stations without a disk.

Compressed-Sensing Reconstruction Based on Block Sparse Bayesian Learning in Bearing-Condition Monitoring

PubMed Central

Sun, Jiedi; Yu, Yang; Wen, Jiangtao

2017-01-01

Remote monitoring of bearing conditions, using wireless sensor network (WSN), is a developing trend in the industrial field. In complicated industrial environments, WSN face three main constraints: low energy, less memory, and low operational capability. Conventional data-compression methods, which concentrate on data compression only, cannot overcome these limitations. Aiming at these problems, this paper proposed a compressed data acquisition and reconstruction scheme based on Compressed Sensing (CS) which is a novel signal-processing technique and applied it for bearing conditions monitoring via WSN. The compressed data acquisition is realized by projection transformation and can greatly reduce the data volume, which needs the nodes to process and transmit. The reconstruction of original signals is achieved in the host computer by complicated algorithms. The bearing vibration signals not only exhibit the sparsity property, but also have specific structures. This paper introduced the block sparse Bayesian learning (BSBL) algorithm which works by utilizing the block property and inherent structures of signals to reconstruct CS sparsity coefficients of transform domains and further recover the original signals. By using the BSBL, CS reconstruction can be improved remarkably. Experiments and analyses showed that BSBL method has good performance and is suitable for practical bearing-condition monitoring. PMID:28635623

EqualWrites: Reducing Intra-set Write Variations for Enhancing Lifetime of Non-volatile Caches

DOE PAGES

Mittal, Sparsh; Vetter, Jeffrey S.

2015-01-29

Driven by the trends of increasing core-count and bandwidth-wall problem, the size of last level caches (LLCs) has greatly increased and hence, the researchers have explored non-volatile memories (NVMs) which provide high density and consume low-leakage power. Since NVMs have low write-endurance and the existing cache management policies are write variation-unaware, effective wear-leveling techniques are required for achieving reasonable cache lifetimes using NVMs. We present EqualWrites, a technique for mitigating intra-set write variation. In this paper, our technique works by recording the number of writes on a block and changing the cache-block location of a hot data-item to redirect themore » future writes to a cold block to achieve wear-leveling. Simulation experiments have been performed using an x86-64 simulator and benchmarks from SPEC06 and HPC (high-performance computing) field. The results show that for single, dual and quad-core system configurations, EqualWrites improves cache lifetime by 6.31X, 8.74X and 10.54X, respectively. In addition, its implementation overhead is very small and it provides larger improvement in lifetime than three other intra-set wear-leveling techniques and a cache replacement policy.« less

Blocking of conditioned taste avoidance induced by wheel running.

PubMed

Pierce, W David; Heth, C Donald

2010-01-01

In Experiment 1, compared to non-reinforced presentation of a food stimulus (A-->no US), the association of a food stimulus with wheel running (A-->US) blocked subsequent avoidance of a distinctive flavor (X), when both the food and flavor were followed by wheel running (AX-->US). Experiment 2 replicated and extended the blocking effect, demonstrating that the amount of avoidance of X after AX-->wheel training depended on the correlation between A-alone trials and wheel running-the predictiveness of the A stimulus. The present study is the first to demonstrate associative blocking of conditioned taste avoidance (CTA) induced by wheel running and strongly implicates associative learning as the basis for this kind of avoidance. 2009 Elsevier B.V. All rights reserved.

Detecting dominant motion patterns in crowds of pedestrians

NASA Astrophysics Data System (ADS)

Saqib, Muhammad; Khan, Sultan Daud; Blumenstein, Michael

2017-02-01

As the population of the world increases, urbanization generates crowding situations which poses challenges to public safety and security. Manual analysis of crowded situations is a tedious job and usually prone to errors. In this paper, we propose a novel technique of crowd analysis, the aim of which is to detect different dominant motion patterns in real-time videos. A motion field is generated by computing the dense optical flow. The motion field is then divided into blocks. For each block, we adopt an Intra-clustering algorithm for detecting different flows within the block. Later on, we employ Inter-clustering for clustering the flow vectors among different blocks. We evaluate the performance of our approach on different real-time videos. The experimental results show that our proposed method is capable of detecting distinct motion patterns in crowded videos. Moreover, our algorithm outperforms state-of-the-art methods.

Creating self-formed meandering channels in laboratory flumes (Invited)

NASA Astrophysics Data System (ADS)

Braudrick, C. A.

2009-12-01

Our ability to construct predictive numerical models for meandering rivers is hampered by the inability to create meandering channels in the laboratory where individual variables can be isolated and controlled. Typically, experimental channels braid, straighten, or cease migration once they develop curvature. By using alfalfa sprouts to provide bank strength and fine sediment to attach point bars to the floodplain, we have successfully created and maintained meandering morphology in a laboratory flume. The 6.1 by 17 m flume has a floodplain slope of approximately 0.005 with a sandy bed and banks that scales as a gravel bed river. The alfalfa sprouts slow bank erosion allowing time for the bars to create new floodplain deposits. The sprouts also increase floodplain roughness, armor new bar deposits, and promote deposition of overbank sediment. The fine sediment, a lightweight plastic that scaled as sand, was crucial for blocking chutes formed between the bar and the floodplain, isolating cut-off channels from the main flow, and creating levees. During this 136-hour long experiment, the channel width stabilized as the channel migrated across the floodplain, and the curvature was recreated following cutoffs. Although the sinuosity (about 1.2) was low relative to meandering channels observed in the field, the spacing of bends was within the upper bounds of field examples. Subsequent experiments with higher bank strength had more limited chute development were able to generate a sinuosity of about 1.4. Scaling analysis indicates that the bank migration rates in the lower sinuosity experiment were approximately 10 times faster than migration rates in the field. A particular challenge in these experiments is maintaining a healthy alfalfa crop. After 15-20 hours of flood flows, the alfalfa begins to die off and new emergent bars need to be seeded. It then takes about 7 days for the alfalfa to grow to the size used in these experiments. The 15-20 hours scale to about one year of flood flows in the field. Therefore experiments that replicate the long-term evolution of meandering rivers would be prohibitively long with alfalfa. Future experiments should therefore focus on developing and testing models that to examine longer-term channel evolution.

Sequential and simultaneous SLAR block adjustment. [spline function analysis for mapping

NASA Technical Reports Server (NTRS)

Leberl, F.

1975-01-01

Two sequential methods of planimetric SLAR (Side Looking Airborne Radar) block adjustment, with and without splines, and three simultaneous methods based on the principles of least squares are evaluated. A limited experiment with simulated SLAR images indicates that sequential block formation with splines followed by external interpolative adjustment is superior to the simultaneous methods such as planimetric block adjustment with similarity transformations. The use of the sequential block formation is recommended, since it represents an inexpensive tool for satisfactory point determination from SLAR images.

Unmixing the Mixing Cost: Contributions from Dimensional Relevance and Stimulus-Response Suppression

ERIC Educational Resources Information Center

Mari-Beffa, Paloma; Cooper, Stephen; Houghton, George

2012-01-01

When participants repeat the same task in a context in which the task may also switch (a mixed block), performance deteriorates compared to when there is only one task repeating (a pure block). Three experiments were designed to assess how perceptual and motor transitions influenced this mixing cost. Experiment 1 provided three pure block…

Parent-Child Play, a Foundation for Positive Relationships: Replacing Stumbling Blocks with Building Blocks

ERIC Educational Resources Information Center

Kuchner, Joan F.

2010-01-01

Parenthood brings many responsibilities both economic and social. In the 21st century, these rarely include the mandate to play with your children. Yet, this emotionally rich experience holds the promise of bringing parents and children together for a mutually rewarding experience that will have repercussions through a lifetime. This paper…

Cool in the Kitchen: Radiation, Conduction, and the Newton "Hot Block" Experiment.

ERIC Educational Resources Information Center

Silverman, Mark P.; Silverman, Christopher R.

2000-01-01

Discusses the history of the development of Newton's Law of Cooling. Describes an experiment conducted in the kitchen that is designed to test the rate of cooling of a hot block of iron. Finds that Newton's law does not represent very well the mechanism of heat loss. (Contains over 10 references.) (WRM)

Improved ultrasonic standard reference blocks

NASA Technical Reports Server (NTRS)

Eitzen, D. G.

1975-01-01

A program to improve the quality, reproducibility and reliability of nondestructive testing through the development of improved ASTM-type ultrasonic reference standards is described. Reference blocks of aluminum, steel, and titanium alloys were considered. Equipment representing the state-of-the-art in laboratory and field ultrasonic equipment was obtained and evaluated. Some RF and spectral data on ten sets of ultrasonic reference blocks were taken as part of a task to quantify the variability in response from nominally identical blocks. Techniques for residual stress, preferred orientation, and microstructural measurements were refined and are applied to a reference block rejected by the manufacturer during fabrication in order to evaluate the effect of metallurgical condition on block response.

The Dynamic Microstructure of Speech Production: Semantic Interference Built on the Fly

ERIC Educational Resources Information Center

Abdel Rahman, Rasha; Melinger, Alissa

2011-01-01

We present 4 experiments investigating dynamic and flexible aspects of semantic activation spread during speech planning. In a semantic blocking paradigm, pictures of objects were presented in categorically homogeneous blocks consisting of semantic category members (e.g., foods), in blocks consisting of seemingly unrelated objects that could…

Master curve captures the effect of domain morphology on ethanol pervaporation through block copolymer membranes

USDA-ARS?s Scientific Manuscript database

We report on the effect of changing nanoscale morphology on pervaporation of ethanol/water mixtures through block copolymer membranes. Experiments were conducted using polystyrene-b-polybutadiene-b-polystyrene (SBS) copolymers with polybutadiene (PB) as the ethanol transporting block, using an 8 wt%...

Smartphone based Tomographic PIV using colored shadows

NASA Astrophysics Data System (ADS)

Aguirre-Pablo, Andres A.; Alarfaj, Meshal K.; Li, Er Qiang; Thoroddsen, Sigurdur T.

2016-11-01

We use low-cost smartphones and Tomo-PIV, to reconstruct the 3D-3C velocity field of a vortex ring. The experiment is carried out in an octagonal tank of water with a vortex ring generator consisting of a flexible membrane enclosed by a cylindrical chamber. This chamber is pre-seeded with black polyethylene microparticles. The membrane is driven by an adjustable impulsive air-pressure to produce the vortex ring. Four synchronized smartphone cameras, of 40 Mpx each, are used to capture the location of particles from different viewing angles. We use red, green and blue LED's as backlighting sources, to capture particle locations at different times. The exposure time on the smartphone cameras are set to 2 seconds, while exposing each LED color for about 80 μs with different time steps that can go below 300 μs. The timing of these light pulses is controlled with a digital delay generator. The backlight is blocked by the instantaneous location of the particles in motion, leaving a shadow of the corresponding color for each time step. The image then is preprocessed to separate the 3 different color fields, before using the MART reconstruction and cross-correlation of the time steps to obtain the 3D-3C velocity field. This proof of concept experiment represents a possible low-cost Tomo-PIV setup.

Optimization of computations for adjoint field and Jacobian needed in 3D CSEM inversion

NASA Astrophysics Data System (ADS)

Dehiya, Rahul; Singh, Arun; Gupta, Pravin K.; Israil, M.

2017-01-01

We present the features and results of a newly developed code, based on Gauss-Newton optimization technique, for solving three-dimensional Controlled-Source Electromagnetic inverse problem. In this code a special emphasis has been put on representing the operations by block matrices for conjugate gradient iteration. We show how in the computation of Jacobian, the matrix formed by differentiation of system matrix can be made independent of frequency to optimize the operations at conjugate gradient step. The coarse level parallel computing, using OpenMP framework, is used primarily due to its simplicity in implementation and accessibility of shared memory multi-core computing machine to almost anyone. We demonstrate how the coarseness of modeling grid in comparison to source (comp`utational receivers) spacing can be exploited for efficient computing, without compromising the quality of the inverted model, by reducing the number of adjoint calls. It is also demonstrated that the adjoint field can even be computed on a grid coarser than the modeling grid without affecting the inversion outcome. These observations were reconfirmed using an experiment design where the deviation of source from straight tow line is considered. Finally, a real field data inversion experiment is presented to demonstrate robustness of the code.

Detection of rebar delamination using modal analysis

NASA Astrophysics Data System (ADS)

Blodgett, David W.

2003-08-01

A non-destructive method for early detection of reinforcement steel bars (re-bar) delamination in concrete structures has been developed. This method, termed modal analysis, has been shown effective in both laboratory and field experiments. In modal analysis, an audio speaker is used to generate flexural resonant modes in the re-bar in reinforced concrete structures. Vibrations associated with these modes are coupled to the surrounding concrete and propagate to the surface where they are detected using a laser vibrometer and/or accelerometer. Monitoring both the frequency and amplitude of these vibrations provides information on the bonding state of the embedded re-bar. Laboratory measurements were performed on several specially prepared concrete blocks with re-bar of varying degrees of simulated corrosion. Field measurements were performed on an old bridge about to be torn down in Howard County, Maryland and the results compared with those obtained using destructive analysis of the bridge after demolition. Both laboratory and field test results show this technique to be sensitive to re-bar delamination.

High-bandwidth prefetcher for high-bandwidth memory

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

Mehta, Sanyam; Kohn, James Robert; Ernst, Daniel Jonathan

A method for prefetching data into a cache is provided. The method allocates an outstanding request buffer ("ORB"). The method stores in an address field of the ORB an address and a number of blocks. The method issues prefetch requests for a degree number of blocks starting at the address. When a prefetch response is received for all the prefetch requests, the method adjusts the address of the next block to prefetch and adjusts the number of blocks remaining to be retrieved and then issues prefetch requests for a degree number of blocks starting at the adjusted address. The prefetchingmore » pauses when a maximum distance between the reads of the prefetched blocks and the last prefetched block is reached. When a read request for a prefetched block is received, the method resumes prefetching when a resume criterion is satisfied.« less

Termites live in a material world: exploration of their ability to differentiate between food sources.

PubMed

Inta, Ra; Lai, Joseph C S; Fu, Eugene W; Evans, Theodore A

2007-08-22

Drywood termites are able to assess wood size using vibratory signals, although the exact mechanism behind this assessment ability is not known. Important vibratory characteristics such as the modal frequencies of a wooden block depend on its geometry and boundary conditions; however, they are also dependent on the material characteristics of the block, such as mass, density and internal damping. We report here on choice experiments that tested the ability of the drywood termite Cryptotermes secundus to assess wooden block size using a solid wooden block paired with a composite block, the latter made of either wood and aluminium or wood and rubber. Each composite block was constructed to match mass or low-frequency vibratory modes (i.e. fundamental frequency) of the solid wooden block. The termites always chose the blocks with more wood; they moved to the solid wooden blocks usually within a day and then tunnelled further into the solid wooden block by the end of the experiment. Termites offered composite blocks of wood and rubber matched for mass were the slowest to show a preference for the solid wooden block and this preference was the least definitive of any treatment, which indicated that mass and/or damping may play a role in food assessment. This result clearly shows that the termites were not fooled by composite blocks matched for mass or frequency, which implies that they probably employ more than a single simple measure in their food assessment strategy. This implies a degree of sophistication in their ability to assess their environment hitherto unknown. The potential importance of alternative features in the vibrational signals is discussed.

Improvement in trapped fields by stacking bulk superconductors

NASA Astrophysics Data System (ADS)

Suzuki, A.; Wongsatanawarid, A.; Seki, H.; Murakami, M.

2009-10-01

We studied the effects of stacking several bulk superconductor blocks on the field trapping properties. In order to avoid the detrimental effects of the bottom deteriorated parts, bulk Dy-Ba-Cu-O superconductors 45 mm in diameter and 10 mm in thickness were cut from the top parts of as-grown bulk blocks of 25 mm diameter. We stacked the superconductors and measured the field distribution as a function of the gap. The trapped field measurements were performed by field-cooling the samples inserted in between two permanent magnets with liquid nitrogen. It was found that the trapped field values are almost doubled when the number of stacked bulk superconductors increased from two to three. The present results clearly show that one can expect beneficial effects of increasing the ratio of the height to the diameter even in bulk high temperature superconductors.

Brain electric microstates and momentary conscious mind states as building blocks of spontaneous thinking: I. Visual imagery and abstract thoughts.

PubMed

Lehmann, D; Strik, W K; Henggeler, B; Koenig, T; Koukkou, M

1998-06-01

Prompted reports of recall of spontaneous, conscious experiences were collected in a no-input, no-task, no-response paradigm (30 random prompts to each of 13 healthy volunteers). The mentation reports were classified into visual imagery and abstract thought. Spontaneous 19-channel brain electric activity (EEG) was continuously recorded, viewed as series of momentary spatial distributions (maps) of the brain electric field and segmented into microstates, i.e. into time segments characterized by quasi-stable landscapes of potential distribution maps which showed varying durations in the sub-second range. Microstate segmentation used a data-driven strategy. Different microstates, i.e. different brain electric landscapes must have been generated by activity of different neural assemblies and therefore are hypothesized to constitute different functions. The two types of reported experiences were associated with significantly different microstates (mean duration 121 ms) immediately preceding the prompts; these microstates showed, across subjects, for abstract thought (compared to visual imagery) a shift of the electric gravity center to the left and a clockwise rotation of the field axis. Contrariwise, the microstates 2 s before the prompt did not differ between the two types of experiences. The results support the hypothesis that different microstates of the brain as recognized in its electric field implement different conscious, reportable mind states, i.e. different classes (types) of thoughts (mentations); thus, the microstates might be candidates for the 'atoms of thought'.

Improving the Curie depth estimation through optimizing the spectral block dimensions of the aeromagnetic data in the Sabalan geothermal field

NASA Astrophysics Data System (ADS)

Akbar, Somaieh; Fathianpour, Nader

2016-12-01

The Curie point depth is of great importance in characterizing geothermal resources. In this study, the Curie iso-depth map was provided using the well-known method of dividing the aeromagnetic dataset into overlapping blocks and analyzing the power spectral density of each block separately. Determining the optimum block dimension is vital in improving the resolution and accuracy of estimating Curie point depth. To investigate the relation between the optimal block size and power spectral density, a forward magnetic modeling was implemented on an artificial prismatic body with specified characteristics. The top, centroid, and bottom depths of the body were estimated by the spectral analysis method for different block dimensions. The result showed that the optimal block size could be considered as the smallest possible block size whose corresponding power spectrum represents an absolute maximum in small wavenumbers. The Curie depth map of the Sabalan geothermal field and its surrounding areas, in the northwestern Iran, was produced using a grid of 37 blocks with different dimensions from 10 × 10 to 50 × 50 km2, which showed at least 50% overlapping with adjacent blocks. The Curie point depth was estimated in the range of 5 to 21 km. The promising areas with the Curie point depths less than 8.5 km are located around Mountain Sabalan encompassing more than 90% of known geothermal resources in the study area. Moreover, the Curie point depth estimated by the improved spectral analysis is in good agreement with the depth calculated from the thermal gradient data measured in one of the exploratory wells in the region.

Optimizing Experimental Designs: Finding Hidden Treasure.

USDA-ARS?s Scientific Manuscript database

Classical experimental design theory, the predominant treatment in most textbooks, promotes the use of blocking designs for control of spatial variability in field studies and other situations in which there is significant variation among heterogeneity among experimental units. Many blocking design...

Operator product expansion for conformal defects

NASA Astrophysics Data System (ADS)

Fukuda, Masayuki; Kobayashi, Nozomu; Nishioka, Tatsuma

2018-01-01

We study the operator product expansion (OPE) for scalar conformal defects of any codimension in CFT. The OPE for defects is decomposed into "defect OPE blocks", the irreducible representations of the conformal group, each of which packages the contribution from a primary operator and its descendants. We use the shadow formalism to deduce an integral representation of the defect OPE blocks. They are shown to obey a set of constraint equations that can be regarded as equations of motion for a scalar field propagating on the moduli space of the defects. By employing the Radon transform between the AdS space and the moduli space, we obtain a formula of constructing an AdS scalar field from the defect OPE block for a conformal defect of any codimension in a scalar representation of the conformal group, which turns out to be the Euclidean version of the HKLL formula. We also introduce a duality between conformal defects of different codimensions and prove the equivalence between the defect OPE block for codimension-two defects and the OPE block for a pair of local operators.

Interfacial fluctuations of block copolymers: a coarse-grain molecular dynamics simulation study.

PubMed

Srinivas, Goundla; Swope, William C; Pitera, Jed W

2007-12-13

The lamellar and cylindrical phases of block copolymers have a number of technological applications, particularly when they occur in supported thin films. One such application is block copolymer lithography, the use of these materials to subdivide or enhance submicrometer patterns defined by optical or electron beam methods. A key parameter of all lithographic methods is the line edge roughness (LER), because the electronic or optical activities of interest are sensitive to small pattern variations. While mean-field models provide a partial picture of the LER and interfacial width expected for the block interface in a diblock copolymer, these models lack chemical detail. To complement mean-field approaches, we have carried out coarse-grain molecular dynamics simulations on model poly(ethyleneoxide)-poly(ethylethylene) (PEO-PEE) lamellae, exploring the influence of chain length and hypothetical chemical modifications on the observed line edge roughness. As expected, our simulations show that increasing chi (the Flory-Huggins parameter) is the most direct route to decreased roughness, although the addition of strong specific interactions at the block interface can also produce smoother patterns.

Improved global prediction of 300 nautical mile mean free air anomalies

NASA Technical Reports Server (NTRS)

Cruz, J. Y.

1982-01-01

Current procedures used for the global prediction of 300nm mean anomalies starting from known values of 1 deg by 1 deg mean anomalies yield unreasonable prediction results when applied to 300nm blocks which have a rapidly varying gravity anomaly field and which contain relatively few observed 60nm blocks. Improvement of overall 300nm anomaly prediction is first achieved by using area-weighted as opposed to unweighted averaging of the 25 generated 60nm mean anomalies inside the 300nm block. Then, improvement of prediction over rough 300nm blocks is realized through the use of fully known 1 deg by 1 deg mean elevations, taking advantage of the correlation that locally exists between 60nm mean anomalies and 60nm mean elevations inside the 300nm block. An improved prediction model which adapts itself to the roughness of the local anomaly field is found to be the model of Least Squares Collocation with systematic parameters, the systematic parameter being the slope b which is a type of Bouguer slope expressing the correlation that locally exists between 60nm mean anomalies and 60nm mean elevations.

Overlapping Ballistic Ejecta Fields: Separating Distinct Blasts at Kings Bowl, Idaho

NASA Astrophysics Data System (ADS)

Borg, C.; Kobs-Nawotniak, S. E.; Hughes, S. S.; Sears, D. W. G.; Heldmann, J. L.; Lim, D. S. S.; Haberle, C. W.; Sears, H.; Elphic, R. C.; Kobayashi, L.; Garry, W. B.; Neish, C.; Karunatillake, S.; Button, N.; Purcell, S.; Mallonee, H.; Ostler, B.

2015-12-01

Kings Bowl is a ~2200ka pit crater created by a phreatic blast along a volcanic fissure in the eastern Snake River Plain (ESRP), Idaho. The main crater measures approximately 80m in length, 30m in width, and 30m in depth, with smaller pits located nearby on the Great Rift fissure, and has been targeted by the FINESSE team as a possible analogue for Cyane Fossae, Mars. The phreatic eruption is believed to have occurred due to the interaction of groundwater with lava draining back into the fissure following a lava lake high stand, erupting already solidified basalt from this and previous ERSP lava flows. The contemporaneous draw back of the lava with the explosions may conceal some smaller possible blast pits as more lava drained into the newly formed pits. Ballistic ejecta from the blasts occur on both sides of the fissure. To the east, the ballistic blocks are mantled by fine tephra mixed with eolian dust, the result of a westerly wind during the explosions. We use differential GPS to map the distribution of ballistic blocks on the west side of the fissure, recording position, percent vesiculation, and the length of 3 mutually perpendicular axes for each block >20cm along multiple transects parallel to the fissure. From the several hundred blocks recorded, we have been able to separate the ballistic field into several distinct blast deposits on the basis of size distributions and block concentration. The smaller pits identified from the ballistic fields correspond broadly to the northern and southern limits of the tephra/dust field east of the fissure. Soil formation and bioturbation of the tephra by sagebrush have obliterated any tephrostratigraphy that could have been linked to individual blasts. The ballistic block patterns at Kings Bowl may be used to identify distinct ejecta groups in high-resolution imagery of Mars or other planetary bodies.

Dynamic blocked transfer stiffness method of characterizing the magnetic field and frequency dependent dynamic viscoelastic properties of MRE

NASA Astrophysics Data System (ADS)

Poojary, Umanath R.; Hegde, Sriharsha; Gangadharan, K. V.

2016-11-01

Magneto rheological elastomer (MRE) is a potential resilient element for the semi active vibration isolator. MRE based isolators adapt to different frequency of vibrations arising from the source to isolate the structure over wider frequency range. The performance of MRE isolator depends on the magnetic field and frequency dependent characteristics of MRE. Present study is focused on experimentally evaluating the dynamic stiffness and loss factor of MRE through dynamic blocked transfer stiffness method. The dynamic stiffness variations of MRE exhibit strong magnetic field and mild frequency dependency. Enhancements in dynamic stiffness saturate with the increase in magnetic field and the frequency. The inconsistent variations of loss factor with the magnetic field substantiate the inability of MRE to have independent control over its damping characteristics.

An Advanced simulation Code for Modeling Inductive Output Tubes

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

Thuc Bui; R. Lawrence Ives

2012-04-27

During the Phase I program, CCR completed several major building blocks for a 3D large signal, inductive output tube (IOT) code using modern computer language and programming techniques. These included a 3D, Helmholtz, time-harmonic, field solver with a fully functional graphical user interface (GUI), automeshing and adaptivity. Other building blocks included the improved electrostatic Poisson solver with temporal boundary conditions to provide temporal fields for the time-stepping particle pusher as well as the self electric field caused by time-varying space charge. The magnetostatic field solver was also updated to solve for the self magnetic field caused by time changing currentmore » density in the output cavity gap. The goal function to optimize an IOT cavity was also formulated, and the optimization methodologies were investigated.« less

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

Sutcliffe, G. D.; Milanese, L. M.; Orozco, D.

CR-39 detectors are used routinely in inertial confinement fusion (ICF) experiments as a part of nuclear diagnostics. CR-39 is filtered to stop fast ablator ions which have been accelerated from an ICF implosion due to electric fields caused by laser-plasma interactions. In some experiments, the filtering is insufficient to block these ions and the fusion-product signal tracks are lost in the large background of accelerated ion tracks. A technique for recovering signal in these scenarios has been developed, tested, and implemented successfully. The technique involves removing material from the surface of the CR-39 to a depth beyond the endpoint ofmore » the ablator ion tracks. The technique preserves signal magnitude (yield) as well as structure in radiograph images. The technique is effective when signal particle range is at least 10 μm deeper than the necessary bulk material removal.« less

Effects of effluent water on the abundance of cowpea insect pests.

PubMed

Tiroesele, Bamphitlhi; Sitwane, Monametsi; Obopile, M; Ullah, Muhammad Irfan; Ali, Sajjad

2017-10-03

Botswana experiences low and unreliable rainfall. Thus, the use of effluent water in agriculture is increasingly important. Insect damage is the major constraint for cowpea grain production in the most cowpea-producing lands. We investigated the effects of effluent water on insect pest abundance on cowpea (Vigna unguiculata) under field conditions. The experiment was laid out in a randomized complete block design with 100, 75, 50, and 25% of effluent water and 0% (control-clean tap water) treatments. Treatments with 100% effluent water resulted in a significant increase in insect pest populations as compared with the control. These results show that the use of effluent water to irrigate crops may increase incidence, abundance, and damage caused by insect pests possibly by decreasing plant vigor. The use of effluent water in agriculture should be addressed in a wise way.

Hydrologic data for Block Island, Rhode Island

USGS Publications Warehouse

Burns, Emily

1993-01-01

This report was compiled as part of a study to assess the hydrogeology and the quality and quantity of fresh ground water on Block Island, Rhode Island. Hydrologic data were collected on Block Island during 1988-91. The data are pre- sented in illustrations and tables. Data collec- ted include precipitation, surfae-water, ground- water, lithologic, and well-construction and dis- charge information. Precipitation data include total monthly precipitation values from 11 rain gages and water-quality analyses of 14 precipi- tation samples from one station. Surface-water data include water-level measurements at 12 ponds, water-quality data for five ponds, and field specific-conductance measurements at 56 surface- water sites (streams, ponds, and springs). Ground- water data include water-level measurements at 159 wells, water-quality data at 150 wells, and field specific-conductance data at 52 wells. Lithologic logs for 375 wells and test borings, and construc- tion and location data for 570 wells, springs, and test borings are included. In addition, the data set contains data on water quality of water samples, collected by the Rhode Island Department of Health during 1976-91, from Fresh and Sands Ponds and from wells at the Block Island Water Company well field north of Sands Pond.

Region 9 - Social Vulnerability Index

EPA Pesticide Factsheets

The Social Vulnerability Index is derived from the 2000 US Census data. The fields included are percent minority, median household income, age (under 18 and over 64), population without a high school diploma, linguistically isolated households, and single female head of households with own children under 18 (single moms). The data is at the block group level. Each field for each block group is assigned an index score of 0-3, based on whether the value of that dataset falls in the top quartile (score=3), second quartile (score=2), third quartile (score=1), or bottom quartile (score=0). The scores for each field are then added together to assign a comprehensive score to each block group (0-21). The highest scores are block groups that have the highest percentage of sensitive populations (highest percent minority, lowest per capita income, highest percent of population under 18 and over 64, highest percentage of population without a high school degree, highest percent of linguistically isolated households, and highest percent of single female head of households). Zoe Heller of the US EPA Region 9's Communities and Ecosystems Division, is responsible for the design and development of the Social Vulnerability Index data set.

Arizona - Social Vulnerability Index

EPA Pesticide Factsheets

The Social Vulnerability Index is derived from the 2000 US Census data. The fields included are percent minority, median household income, age (under 18 and over 64), population without a high school diploma, linguistically isolated households, and single female head of households with own children under 18 (single moms). The data is at the block group level. Each field for each block group is assigned an index score of 0-3, based on whether the value of that dataset falls in the top quartile (score=3), second quartile (score=2), third quartile (score=1), or bottom quartile (score=0). The scores for each field are then added together to assign a comprehensive score to each block group (0-21). The highest scores are block groups that have the highest percentage of sensitive populations (highest percent minority, lowest per capita income, highest percent of population under 18 and over 64, highest percentage of population without a high school degree, highest percent of linguistically isolated households, and highest percent of single female head of households). Zoe Heller of the US EPA Region 9's Communities and Ecosystems Division, is responsible for the design and development of the Social Vulnerability Index data set.

Damage sensitivity investigations of EMI technique on different materials through coupled field analysis

NASA Astrophysics Data System (ADS)

Joshi, Bhrigu; Adhikari, Sailesh; Bhalla, Suresh

2016-04-01

This paper presents a comparative study through the piezoelectric coupled field analysis mode of finite element method (FEM) on detection of damages of varying magnitude, encompassing three different types of structural materials, using piezo impedance transducers. An aluminum block, a concrete block and a steel block of dimensions 48×48×10 mm were modelled in finite element software ANSYS. A PZT patch of 10×10×0.3 mm was also included in the model as surface bonded on the block. Coupled field analysis (CFA) was performed to obtain the admittance signatures of the piezo sensor in the frequency range of 0-250 kHz. The root mean square deviation (RMSD) index was employed to quantify the degree of variation of the signatures. It was found that concrete exhibited deviation in the signatures only with the change of damping values. However, the other two materials showed variation in the signatures even with changes in density and elasticity values in a small portion of the specimen. The comparative study shows that the PZT patches are more sensitive to damage detection in materials with low damping and the sensitivity typically decreases with increase in the damping.

New algorithms for field-theoretic block copolymer simulations: Progress on using adaptive-mesh refinement and sparse matrix solvers in SCFT calculations

NASA Astrophysics Data System (ADS)

Sides, Scott; Jamroz, Ben; Crockett, Robert; Pletzer, Alexander

2012-02-01

Self-consistent field theory (SCFT) for dense polymer melts has been highly successful in describing complex morphologies in block copolymers. Field-theoretic simulations such as these are able to access large length and time scales that are difficult or impossible for particle-based simulations such as molecular dynamics. The modified diffusion equations that arise as a consequence of the coarse-graining procedure in the SCF theory can be efficiently solved with a pseudo-spectral (PS) method that uses fast-Fourier transforms on uniform Cartesian grids. However, PS methods can be difficult to apply in many block copolymer SCFT simulations (eg. confinement, interface adsorption) in which small spatial regions might require finer resolution than most of the simulation grid. Progress on using new solver algorithms to address these problems will be presented. The Tech-X Chompst project aims at marrying the best of adaptive mesh refinement with linear matrix solver algorithms. The Tech-X code PolySwift++ is an SCFT simulation platform that leverages ongoing development in coupling Chombo, a package for solving PDEs via block-structured AMR calculations and embedded boundaries, with PETSc, a toolkit that includes a large assortment of sparse linear solvers.

Ion solvation in polymer blends and block copolymer melts: effects of chain length and connectivity on the reorganization of dipoles.

PubMed

Nakamura, Issei

2014-05-29

We studied the thermodynamic properties of ion solvation in polymer blends and block copolymer melts and developed a dipolar self-consistent field theory for polymer mixtures. Our theory accounts for the chain connectivity of polymerized monomers, the compressibility of the liquid mixtures under electrostriction, the permanent and induced dipole moments of monomers, and the resultant dielectric contrast among species. In our coarse-grained model, dipoles are attached to the monomers and allowed to rotate freely in response to electrostatic fields. We demonstrate that a strong electrostatic field near an ion reorganizes dipolar monomers, resulting in nonmonotonic changes in the volume fraction profile and the dielectric function of the polymers with respect to those of simple liquid mixtures. For the parameter sets used, the spatial variations near an ion can be in the range of 1 nm or larger, producing significant differences in the solvation energy among simple liquid mixtures, polymer blends, and block copolymers. The solvation energy of an ion depends substantially on the chain length in block copolymers; thus, our theory predicts the preferential solvation of ions arising from differences in chain length.

Liquid cooling applications on automotive exterior LED lighting

NASA Astrophysics Data System (ADS)

Aktaş, Mehmet; Şenyüz, Tunç; Şenyıldız, Teoman; Kılıç, Muhsin

2018-02-01

In this study cooling of a LED unit with heatsink and liquid cooling block which is used in automotive head lamp applications has been investigated numerically and experimentally. Junction temperature of a LED which is cooled with heatsink and liquid cooling block obtained in the experiment. 23°C is used both in the simulation and the experiment phase. Liquid cooling block material is choosed aluminium (Al) and polyamide. All tests and simulation are performed with three different flow rate. Temperature distribution of the designed product is investigated by doing the numerical simulations with a commercially software. In the simulations, fluid flow is assumed to be steady, incompressible and laminar and 3 dimensional (3D) Navier-Stokes equations are used. According to the calculations it is obtained that junction temperature is higher in the heatsink design compared to block cooled one. By changing the block material, it is desired to investigate the variation on the LED junction temperature. It is found that more efficient cooling can be obtained in block cooling by using less volume and weight. With block cooling lifetime of LED can be increased and flux loss can be decreased with the result of decreased junction temperature.

Improved ultrasonic standard reference blocks

NASA Technical Reports Server (NTRS)

Eitzen, D. G.; Sushinsky, G. F.; Chwirut, D. J.; Bechtoldt, C. J.; Ruff, A. W.

1976-01-01

A program to improve the quality, reproducibility and reliability of nondestructive testing through the development of improved ASTM-type ultrasonic reference standards is described. Reference blocks of aluminum, steel, and titanium alloys are to be considered. Equipment representing the state-of-the-art in laboratory and field ultrasonic equipment was obtained and evaluated. RF and spectral data on ten sets of ultrasonic reference blocks have been taken as part of a task to quantify the variability in response from nominally identical blocks. Techniques for residual stress, preferred orientation, and micro-structural measurements were refined and are applied to a reference block rejected by the manufacturer during fabrication in order to evaluate the effect of metallurgical condition on block response. New fabrication techniques for reference blocks are discussed and ASTM activities are summarized.

Band gap control using electric field of photonic gel cells fabricated with block copolymer and hydrogel.

PubMed

Lee, Sung Nam; Baek, Young Bin; Shin, Dong Myung

2014-08-01

Optical and electrical characteristics of the devices using photonic gel film and hydrogel electrolyte were studied. Poly(styrene-b-2-vinylpyridine) (PS-b-P2VP) lamellar film with alternating hydrophobic block and hydrophilic polyelectrolyte block polymers (52 kg/mol-b-57 kg/mol) were prepared for the photonic gel. Poly(isobutylene-co-maleic acid) sodium salts were prepared for the hydrogel. This hydrogel fiber is common water swelling material and it owned ions for a device has conductivity. Photonic gel and hydrogel was spin coating onto Indium-tin-oxide (ITO) glass for make electric fields. The reflectance maximum wavelength of photonic crystal device shifted from 538 nm and reached to 557 nm, 585 nm and 604 nm during 30 min voltage applying time. The bandwidth variation was very limited. Loss of electrolyte was much less with hydrogel compared to the pure water. We can control color of hydrogel used photonic device by electric field with reasonable time range under moderate electric field by applying 2 V between two facing electrodes.

Film growth kinetics and electric field patterning during electrospray deposition of block copolymer thin films

NASA Astrophysics Data System (ADS)

Toth, Kristof; Hu, Hanqiong; Choo, Youngwoo; Loewenberg, Michael; Osuji, Chinedum

The delivery of sub-micron droplets of dilute polymer solutions to a heated substrate by electrospray deposition (ESD) enables precisely controlled and continuous growth of block copolymer (BCP) thin films. Here we explore patterned deposition of BCP films by spatially varying the electric field at the substrate using an underlying charged grid, as well as film growth kinetics. Numerical analysis was performed to examine pattern fidelity by considering the trajectories of charged droplets during flight through imposed periodic field variations in the vicinity of the substrate. Our work uncovered an unexpected modality for improving the resolution of the patterning process via stronger field focusing through the use of a second oppositely charged grid beneath a primary focusing array, with an increase in highly localized droplet deposition on the intersecting nodes of the grid. Substrate coverage kinetics are considered for homopolymer deposition in the context of simple kinetic models incorporating temperature and molecular weight dependence of diffusivity. By contrast, film coverage kinetics for block copolymer depositions are additionally convoluted with preferential wetting and thickness-periodicity commensurability effects. NSF GRFP.

A stochastic approach to uncertainty in the equations of MHD kinematics

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

Phillips, Edward G., E-mail: egphillips@math.umd.edu; Elman, Howard C., E-mail: elman@cs.umd.edu

2015-03-01

The magnetohydrodynamic (MHD) kinematics model describes the electromagnetic behavior of an electrically conducting fluid when its hydrodynamic properties are assumed to be known. In particular, the MHD kinematics equations can be used to simulate the magnetic field induced by a given velocity field. While prescribing the velocity field leads to a simpler model than the fully coupled MHD system, this may introduce some epistemic uncertainty into the model. If the velocity of a physical system is not known with certainty, the magnetic field obtained from the model may not be reflective of the magnetic field seen in experiments. Additionally, uncertaintymore » in physical parameters such as the magnetic resistivity may affect the reliability of predictions obtained from this model. By modeling the velocity and the resistivity as random variables in the MHD kinematics model, we seek to quantify the effects of uncertainty in these fields on the induced magnetic field. We develop stochastic expressions for these quantities and investigate their impact within a finite element discretization of the kinematics equations. We obtain mean and variance data through Monte Carlo simulation for several test problems. Toward this end, we develop and test an efficient block preconditioner for the linear systems arising from the discretized equations.« less

The Significance of Event Information for 6- to 16-Month-Old Infants' Perception of Containment

ERIC Educational Resources Information Center

Smitsman, Ad W.; Dejonckheere, Peter J. N.; De Wit, Tessa C. J.

2009-01-01

Four experiments familiarized 6-, 9-, 12-, and 16-month-old infants to a solid block that was repeatedly lowered into a semitransparent container. In test trials the end state, containment, was either compatible or incompatible with the objects' size and position. In Experiment 1, infants saw the block and box successively before they observed the…

The Effects of Spatial Endogenous Pre-cueing across Eccentricities

PubMed Central

Feng, Jing; Spence, Ian

2017-01-01

Frequently, we use expectations about likely locations of a target to guide the allocation of our attention. Despite the importance of this attentional process in everyday tasks, examination of pre-cueing effects on attention, particularly endogenous pre-cueing effects, has been relatively little explored outside an eccentricity of 20°. Given the visual field has functional subdivisions that attentional processes can differ significantly among the foveal, perifoveal, and more peripheral areas, how endogenous pre-cues that carry spatial information of targets influence our allocation of attention across a large visual field (especially in the more peripheral areas) remains unclear. We present two experiments examining how the expectation of the location of the target shapes the distribution of attention across eccentricities in the visual field. We measured participants’ ability to pick out a target among distractors in the visual field after the presentation of a highly valid cue indicating the size of the area in which the target was likely to occur, or the likely direction of the target (left or right side of the display). Our first experiment showed that participants had a higher target detection rate with faster responses, particularly at eccentricities of 20° and 30°. There was also a marginal advantage of pre-cueing effects when trials of the same size cue were blocked compared to when trials were mixed. Experiment 2 demonstrated a higher target detection rate when the target occurred at the cued direction. This pre-cueing effect was greater at larger eccentricities and with a longer cue-target interval. Our findings on the endogenous pre-cueing effects across a large visual area were summarized using a simple model to assist in conceptualizing the modifications of the distribution of attention over the visual field. We discuss our finding in light of cognitive penetration of perception, and highlight the importance of examining attentional process across a large area of the visual field. PMID:28638353

The Effects of Spatial Endogenous Pre-cueing across Eccentricities.

PubMed

Feng, Jing; Spence, Ian

2017-01-01

Frequently, we use expectations about likely locations of a target to guide the allocation of our attention. Despite the importance of this attentional process in everyday tasks, examination of pre-cueing effects on attention, particularly endogenous pre-cueing effects, has been relatively little explored outside an eccentricity of 20°. Given the visual field has functional subdivisions that attentional processes can differ significantly among the foveal, perifoveal, and more peripheral areas, how endogenous pre-cues that carry spatial information of targets influence our allocation of attention across a large visual field (especially in the more peripheral areas) remains unclear. We present two experiments examining how the expectation of the location of the target shapes the distribution of attention across eccentricities in the visual field. We measured participants' ability to pick out a target among distractors in the visual field after the presentation of a highly valid cue indicating the size of the area in which the target was likely to occur, or the likely direction of the target (left or right side of the display). Our first experiment showed that participants had a higher target detection rate with faster responses, particularly at eccentricities of 20° and 30°. There was also a marginal advantage of pre-cueing effects when trials of the same size cue were blocked compared to when trials were mixed. Experiment 2 demonstrated a higher target detection rate when the target occurred at the cued direction. This pre-cueing effect was greater at larger eccentricities and with a longer cue-target interval. Our findings on the endogenous pre-cueing effects across a large visual area were summarized using a simple model to assist in conceptualizing the modifications of the distribution of attention over the visual field. We discuss our finding in light of cognitive penetration of perception, and highlight the importance of examining attentional process across a large area of the visual field.

Drilling into a present-day migration pathway for hydrocarbons within a fault zone conduit in the Eugene Island 330 field, offshore Louisiana

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

Anderson, R.N.

1995-11-01

Within the Global Basins Research Network, we have developed 4-D seismic analysis techniques that, when integrated with pressure and temperature mapping, production history, geochemical monitoring, and finite element modeling, allow for the imaging of active fluid migration in the subsurface. We have imaged fluid flow pathways that are actively recharging shallower hydrocarbon reservoirs in the Eugene Island 330 field, offshore Louisiana. The hydrocarbons appear to be sourcing from turbidite stacks within the salt-withdrawal mini-basin buried deep within geopressure. Fault zone conduits provide transient migration pathways out of geopressure. To accomplish this 4-D imaging, we use multiple 3-D seismic surveys donemore » several years apart over the same blocks. 3-D volume processing and attribute analysis algorithms are used to identify significant seismic amplitude interconnectivity and changes over time that result from active fluid migration. Pressures and temperatures are then mapped and modeled to pro- vide rate and timing constraints for the fluid movement. Geochemical variability observed in the shallow reservoirs is attributed to the mixing of new with old oils. The Department of Energy has funded an industry cost-sharing project to drill into one of these active conduits in Eugene Island Block 330. Active fluid flow was encountered within the fault zone in the field demonstration experiment, and hydrocarbons were recovered. The active migration events connecting shallow reservoirs to deep sourcing regions imply that large, heretofore undiscovered hydrocarbon reserves exist deep within geopressures along the deep continental shelf of the northern Gulf of Mexico.« less

Fluorescence Lifetime Study of Cyclodextrin Complexes of Substituted Naphthalenes.

DTIC Science & Technology

1987-08-15

Spectroscopy iip 17. COSATI CODES 18. SUBJECT TERMS (Continue on reverse If necessary and identify by block number) FIELD GROUP SUB-GROUP fluorescence lifetime...measurements cyclodextrins spectroscopic techniques 19. TRACT (Continue on revere if necsary and identify by block number

Predictive and postdictive analysis of forage yield trials

USDA-ARS?s Scientific Manuscript database

Classical experimental design theory, the predominant treatment in most textbooks, promotes the use of blocking designs for control of spatial variability in field studies and other situations in which there is significant variation among heterogeneity among experimental units. Many blocking design...

Blocking of Goal-Location Learning Based on Shape

ERIC Educational Resources Information Center

Alexander, Tim; Wilson, Stuart P.; Wilson, Paul N.

2009-01-01

Using desktop, computer-simulated virtual environments (VEs), the authors conducted 5 experiments to investigate blocking of learning about a goal location based on Shape B as a consequence of preliminary training to locate that goal using Shape A. The shapes were large 2-dimensional horizontal figures on the ground. Blocking of spatial learning…

Are Abstract and Concrete Concepts Organized Differently? Evidence from the Blocked Translation Paradigm

ERIC Educational Resources Information Center

Zhang, Xiaohong; Han, Zaizhu; Bi, Yanchao

2013-01-01

Using the blocked-translation paradigm with healthy participants, we examined Crutch and Warrington's hypothesis that concrete and abstract concepts are organized by distinct principles: concrete concepts by semantic similarities and abstract ones by associations. In three experiments we constructed two types of experimental blocking (similar…

Reminder about potentially serious problems with a type of blocked ANOVA analysis

Treesearch

Steve Verrill; David E. Kretschmann

2017-01-01

A type of blocked experiment has the potential of being poorly designed and/or analyzed. Verrill (1993, 1999) and Verrill et al. (2004) referred to such an experiment as a “predictor sort” experiment. David and Gunnink (1997) described the procedure as “artificial pairing.” In textbooks it is sometimes referred to as a “matched pair” or a “matched...

Experimental, Pathologic, and Clinical Findings of Radiofrequency Catheter Ablation of Para-Hisian Region From the Right Ventricle in Dogs and Humans.

PubMed

Xue, Yumei; Zhan, Xianzhang; Wu, Shulin; Wang, Hongyue; Liu, Yang; Liao, Zili; Deng, Hai; Duan, Xuejing; Zeng, Shaoying; Liang, Dongpo; Elvan, Arif; Fang, Xianhong; Liao, Hongtao; Ramdat Misier, Anand R; Smit, Jaap Jan J; Metzner, Andreas; Heeger, Christian-Hendrik; Liu, Fangzhou; Wang, Feng; Zhang, Zhiwei; Kuck, Karl-Heinz; Yen Ho, Siew; Ouyang, Feifan

2017-06-01

Ablation of para-Hisian accessory pathway (AP) poses high risks of atrioventricular block. We developed a pacing technique to differentiate the near-field (NF) from far-field His activations to avoid the complication. Three-dimensional mapping of the right ventricle was performed in 15 mongrel dogs and 23 patients with para-Hisian AP. Using different pacing outputs, the NF- and far-field His activation was identified on the ventricular aspect. Radiofrequency application was delivered at the NF His site in 8 (group 1) and the far-field His site in 7 dogs (group 2), followed by pathologic examination after 14 days. NF His activation was captured with 5 mA/1 ms in 10 and 10 mA/1 ms in 5 dogs. In group 1, radiofrequency delivery resulted in complete atrioventricular block in 3, right bundle branch block with HV (His-to-ventricular) interval prolongation in 1, and only right bundle branch block in 2 dogs, whereas no changes occurred in group 2. Pathologic examination in group-1 dogs showed complete or partial necrosis of the His bundle in 4 and complete necrosis of the right bundle branch in 5 dogs. In group 2, partial necrosis in the right bundle branch was found only in 1 dog. Using this pacing technique, the APs were 5.7±1.2 mm away from the His bundle located superiorly in 20 or inferiorly in 3 patients. All APs were successfully eliminated with 1 to 3 radiofrequency applications. No complications and recurrence occurred during a follow-up of 11.8±1.4 months. Differentiating the NF His from far-field His activations led to a high ablation success without atrioventricular block in para-Hisian AP patients. © 2017 American Heart Association, Inc.

Dynamics of a Dirac oscillator coupled to an external field: a new class of solvable problems

NASA Astrophysics Data System (ADS)

Sadurní, E.; Torres, J. M.; Seligman, T. H.

2010-07-01

The Dirac oscillator coupled to an external two-component field can retain its solvability, if couplings are appropriately chosen. This provides a new class of integrable systems. A simplified way of a solution is given by recasting the known solution of the Dirac oscillator into matrix form; there one notes that a block-diagonal form arises in a Hamiltonian formulation. The blocks are two dimensional. Choosing couplings that do not affect the block structure, these blow up the 2 × 2 matrices to 4 × 4 matrices, thus conserving solvability. The result can be cast again in covariant form. By way of an example we apply this exact solution to calculate the evolution of entanglement.

A switchable polymer layer: Chain folding in end-charged polymer brushes

NASA Astrophysics Data System (ADS)

Heine, David; Wu, David T.

2001-03-01

We use a self-consistent field approximation to model the configurations of end-charged homopolymer and block copolymer brushes in response to an external electric field due to charges on the grafting surface. By varying the charge density on the grafting surface, we can cause the chains either to extend outward, greatly increasing the brush height, or to loop back to the grafting surface. We show that such a copolymer brush can present one block at the exposed surface in the extended state and present the other block in the retracted state. This occurs for both a solvated brush and a dry brush. We also compare these results to those of a modified Alexander-de Gennes model for the end-charged homopolymer brush.

Conceptual design of a compact high gradient quadrupole magnet of varying strength using permanent magnets

NASA Astrophysics Data System (ADS)

Sinha, Gautam

2018-02-01

A concept is presented to design magnets using cylindrical-shaped permanent-magnet blocks, where various types of magnetic fields can be produced by either rotating or varying the size of the magnetic blocks within a given mechanical structure. A general method is introduced to calculate the 3D magnetic field produced by a set of permanent magnets. An analytical expression of the 2D field and the condition to generate various magnetic fields like dipole, quadrupole, and sextupole are derived. Using the 2D result as a starting point, a computer code is developed to get the optimum orientation of the magnets to obtain the user-specific target field profile over a given volume in 3D. Designs of two quadrupole magnets are presented, one using 12 and the other using 24 permanent-magnet blocks. Variation of the quadrupole strength is achieved using tuning coils of a suitable current density and specially designed end tubes. A new concept is introduced to reduce the integrated quadrupole field strength by inserting two hollow cylindrical tubes made of iron, one at each end. This will not affect the field gradient at the center but reduce the integrated field strength by shielding the magnetic field near the ends where the tubes are inserted. The advantages of this scheme are that it is easy to implement, the magnetic axis will not shift, and it will prevent interference with nearby devices. Around 40% integrated field variation is achieved using this method in the present example. To get a realistic estimation of the field quality, a complete 3D model using a nonlinear B -H curve is also studied using a finite-element-based computer code. An example to generate around an 80 T /m quadrupole field gradient is also presented.

Mitigation of Sri Lanka Island Effects in Colombo Sounding Data during DYNAMO

NASA Astrophysics Data System (ADS)

Ciesielski, P. E.; Johnson, R. H.; Yoneyama, K.

2013-12-01

During the Dynamics of the MJO (DYNAMO) field campaign, upper-air soundings were launched at Colombo, Sri Lanka as part of the enhanced northern sounding array (NSA) of the experiment. The Colombo soundings were affected at low-levels by diurnal heating of this large island and by flow blocking due to elevated terrain to the east of the Colombo site. Because of the large spacing between sounding sites, these small-scale effects are aliased onto the larger scale impacting analyses and atmospheric budgets over the DYNAMO NSA. To mitigate these local island effects on the large-scale budgets, a procedure was designed which uses ECMWF-analyzed fields in the vicinity of Sri Lanka to estimate open-ocean conditions (i.e, as if this island were not present). These 'unperturbed' ECMWF fields at low-levels are then merged with observed Colombo soundings. This procedure effectively mutes the blocking effects and large diurnal cycle observed in the low-level Colombo fields. In westerly flow regimes, adjusted Colombo winds increase the low-level westerlies by 2-3 m/s with a similar increase of the low-level easterlies in easterly flow regimes. In general, over the NSA the impact of the adjusted Colombo winds results in more low-level divergence (convergence), more mid-level subsidence (rising motion) and reduced (increased) rainfall during the westerly (easterly) wind regimes. In comparison to independent TRMM rainfall estimates, both the mean budget-derived rainfall and its temporal correlation are improved by using the adjusted Colombo soundings. In addition, use of the 'unperturbed' fields result in a more realistic moisture budget analyses, both in its diurnal cycle and during the build-up phase of the November MJO when a gradual deepening of apparent drying was observed. Overall, use of the adjusted Colombo soundings appears to have a beneficial impact on the NSA analyses and budgets.

Estimated intensity of the EMP from lightning discharges necessary for elves initiation based on balloon experiment

NASA Astrophysics Data System (ADS)

Kondo, S.; Yoshida, A.; Takahashi, Y.; Chikada, S.; Adachi, T.; Sakanoi, T.

2007-12-01

Transient optical phenomena in the mesosphere and lower ionosphere called transient luminous events (TLEs) have been investigated extensively since the first discovery in 1989. In the lower ionosphere, elves are generated by the electromagnetic pulses (EMPs) radiated from the intense lightning current. On the ground-based observation, cameras can not always identify the occurrence of elves because elves emission is sometimes reduced significantly by the atmosphere and blocked by clouds. Therefore, it has been difficult to determine the threshold of intensity of EMPs necessary for initiation of elves. We simultaneously carried out optical and sferics measurements for TLEs and lightning discharges using a high altitude balloon launched at Sanriku Balloon Center on the night of August 25 / 26 in 2006. We fixed four CCD cameras on the gondola, each of which had horizontal FOV of ~100 degree. They cover 360 degree in horizontal direction and imaged the TLEs without atmospheric extinction nor blocking by clouds. The frame rate is 30 fps. We installed three dipole antennas at the gondola, which received the vertical and horizontal electric fields radiated from lightning discharges. The frequency range of the VLF receiver is 1-25 kHz. We also make use of VLF sferics data obtained by ground-based antennas located at Tohoku University in Sendai. We picked up six elves from the image data set obtained by the CCD cameras, and examined the maximum amplitudes of the vertical electric field for 22 lightning discharge events including the six elves events observed both at the balloon and at Sendai. It is found that the maximum amplitudes of the vertical electric field in the five elves events are much larger than those in the other lightning events. We estimate the intensity of the radiated electric field necessary for elves. About one elves event, we don't see intense vertical electric field in the balloon data.

Feedback Effects in Computer-Based Skill Learning

DTIC Science & Technology

1989-09-12

SUPPLEMENTARY NOTATION 17 COSATI CODES 18 SUBJECT TERMS (Continue on reverse if necessary and identify by block number) r FIELD GROUP SUB-GROUP I...rather than tangible feedback ( Barringer & Gholson, 1979) and when they receive punishment (either alone or witih reward) rather than reward alone...34graphed" response latencies across the four conditions ( r = .58), indicating that subjects were sensitive to block-by-block trends in their response

Paleogene volcanism in Central Afghanistan: Possible far-field effect of the India-Eurasia collision

NASA Astrophysics Data System (ADS)

Motuza, Gediminas; Šliaupa, Saulius

2017-10-01

A volcanic-sedimentary succession of Paleogene age is exposed in isolated patches at the southern margin of the Tajik block in the Ghor province of Central Afghanistan. The volcanic rocks range from basalts and andesites to dacites, including adakites. They are intercalated with sedimentary rocks deposited in shallow marine environments, dated biostratigraphically as Paleocene-Eocene. This age corresponds to the age of the Asyābēd andesites located in the western Ghor province estimated by the 40Ar/39Ar method as 54 Ma. The magmatism post-dates the Cimmerian collision between the Tajik block (including the Band-e-Bayan block) and the Farah Rod block located to the south. While the investigated volcanic rocks apparently bear geochemical signatures typical to an active continental margin environment, it is presumed that the magmatism was related to rifting processes most likely initiated by far-field tectonics caused by the terminal collision of the Indian plate with Eurasia (Najman et al., 2017). This event led to the dextral movement of the Farah Rod block, particularly along Hari Rod (Herat) fault system, resulting in the development of a transtensional regime in the proximal southern margin of the Tajik block and giving rise to a rift basin where marine sediments were interbedded with pillow lavas intruded by sheeted dyke series.

Functional level-set derivative for a polymer self consistent field theory Hamiltonian

NASA Astrophysics Data System (ADS)

Ouaknin, Gaddiel; Laachi, Nabil; Bochkov, Daniil; Delaney, Kris; Fredrickson, Glenn H.; Gibou, Frederic

2017-09-01

We derive functional level-set derivatives for the Hamiltonian arising in self-consistent field theory, which are required to solve free boundary problems in the self-assembly of polymeric systems such as block copolymer melts. In particular, we consider Dirichlet, Neumann and Robin boundary conditions. We provide numerical examples that illustrate how these shape derivatives can be used to find equilibrium and metastable structures of block copolymer melts with a free surface in both two and three spatial dimensions.

Testing strong-segregation theory against self-consistent-field theory for block copolymer melts

NASA Astrophysics Data System (ADS)

Matsen, M. W.

2001-06-01

We introduce a highly efficient self-consistent-field theory (SCFT) method for examining the cylindrical and spherical block copolymer morphologies using a standard unit cell approximation (UCA). The method is used to calculate the classical diblock copolymer phase boundaries deep into the strong-segregation regime, where they can be compared with recent improvements to strong-segregation theory (SST). The comparison suggests a significant discrepancy between the two theories indicating that our understanding of strongly stretched polymer brushes is still incomplete.

How to induce defense responses in wild plant populations? Using bilberry (Vaccinium myrtillus) as example.

PubMed

Seldal, Tarald; Hegland, Stein Joar; Rydgren, Knut; Rodriguez-Saona, Cesar; Töpper, Joachim Paul

2017-03-01

Inducible plant defense is a beneficial strategy for plants, which imply that plants should allocate resources from growth and reproduction to defense when herbivores attack. Plant ecologist has often studied defense responses in wild populations by biomass clipping experiments, whereas laboratory and greenhouse experiments in addition apply chemical elicitors to induce defense responses. To investigate whether field ecologists could benefit from methods used in laboratory and greenhouse studies, we established a randomized block-design in a pine-bilberry forest in Western Norway. We tested whether we could activate defense responses in bilberry ( Vaccinium myrtillus ) by nine different treatments using clipping (leaf tissue or branch removal) with or without chemical treatment by methyljasmonate (MeJA). We subsequently measured consequences of induced defenses through vegetative growth and insect herbivory during one growing season. Our results showed that only MeJA-treated plants showed consistent defense responses through suppressed vegetative growth and reduced herbivory by leaf-chewing insects, suggesting an allocation of resources from growth to defense. Leaf tissue removal reduced insect herbivory equal to the effect of the MeJa treatments, but had no negative impact on growth. Branch removal did not reduce insect herbivory or vegetative growth. MeJa treatment and clipping combined did not give an additional defense response. In this study, we investigated how to induce defense responses in wild plant populations under natural field conditions. Our results show that using the chemical elicitor MeJA, with or without biomass clipping, may be a better method to induce defense response in field experiments than clipping of leaves or branches that often has been used in ecological field studies.

Low-cost modular array-field designs for flat-panel and concentrator photovoltaic systems

NASA Astrophysics Data System (ADS)

Post, H. N.; Carmichael, D. C.; Alexander, G.; Castle, J. A.

1982-09-01

Described are the design and development of low-cost, modular array fields for flat-panel and concentrator photovoltaic (PV) systems. The objective of the work was to reduce substantially the cost of the array-field Balance-of-System (BOS) subsystems and site-specific design costs as compared to previous PV installations. These subsystems include site preparation, foundations, support structures, electrical writing, grounding, lightning protection, electromagnetic interference considerations, and controls. To reduce these BOS and design costs, standardized modular (building-block) designs for flat-panel and concentrator array fields have been developed that are fully integrated and optimized for lowest life-cycle costs. Using drawings and specifications now available, these building-block designs can be used in multiples to install various size array fields. The developed designs are immediately applicable (1982) and reduce the array-field BOS costs to a fraction of previous costs.

A Study on Field Emission Characteristics of Planar Graphene Layers Obtained from a Highly Oriented Pyrolyzed Graphite Block

PubMed Central

2009-01-01

This paper describes an experimental study on field emission characteristics of individual graphene layers for vacuum nanoelectronics. Graphene layers were prepared by mechanical exfoliation from a highly oriented pyrolyzed graphite block and placed on an insulating substrate, with the resulting field emission behavior investigated using a nanomanipulator operating inside a scanning electron microscope. A pair of tungsten tips controlled by the nanomanipulator enabled electric connection with the graphene layers without postfabrication. The maximum emitted current from the graphene layers was 170 nA and the turn-on voltage was 12.1 V. PMID:20596315

Laboratory experiments of heat and moisture fluxes through supraglacial debris

NASA Astrophysics Data System (ADS)

Nicholson, Lindsey; Mayer, Christoph; Wirbel, Anna

2014-05-01

Inspired by earlier work (Reznichenko et al., 2010), we have carried out experiments within a climate chamber to explore the best ways to measure the heat and moisture fluxes through supraglacial debris. Sample ice blocks were prepared with debris cover of varying lithology, grain size and thickness and were instrumented with a combination of Gemini TinyTag temperature/relative humidity sensors and Decagon soil moisture sensors in order to monitor the heat and moisture fluxes through the overlying debris material when the experiment is exposed to specified solar lamp radiation and laminar airflow within the temperature-controlled climate chamber. Experimental results can be used to determine the optimal set up for numerical models of heat and moisture flux through supraglacial debris and also indicate the performance limitations of such sensors that can be expected in field installations. Reznichenko, N., Davies, T., Shulmeister, J. and McSaveney, M. (2010) Effects of debris on ice-surface melting rates: an experimental study. Journal of Glaciology, Volume 56, Number 197, 384-394.

The building blocks of drinking experience across men and women: A case study with craft and industrial beers.

PubMed

Gómez-Corona, Carlos; Escalona-Buendía, Héctor B; Chollet, Sylvie; Valentin, Dominique

2017-09-01

In today's market, every product seems to be marked by the label of "experience". It is expected that successful products give the consumer "extraordinary experiences". The research in consumption experience is growing, but much work still needs to be done to understand the food and beverage experience. A qualitative study was conducted using contextual focus groups to explore the building blocks of consumers' drinking experience of industrial and craft beers. The results show that drinking experience is shaped by our cognitive, sensory or affective systems, especially during the core consumption experience. Elements such as attitudes, consumption habits, and individual versus social consumption, shopping experience and product benefits are also responsible for shaping the experience, but are more relevant during the pre-consumption or post-consumption experience. Gender differences occur more frequently in the affective experience, as women search more for relaxation while men for excitement and stimulation while drinking beer. When comparing industrial users versus craft, in the latter the cognitive and shopping experiences are more relevant. Overall, the results showed that the drinking experience of beers can be studied as a function of the salient human system used during product interaction, and this systems act as the building blocks of the drinking experience of beer. This information can be applied in consumer research studies to further study the experiential differences across products and consumers. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evacuation simulation with consideration of obstacle removal and using game theory

NASA Astrophysics Data System (ADS)

Lin, Guan-Wen; Wong, Sai-Keung

2018-06-01

In this paper, we integrate a cellular automaton model with game theory to simulate crowd evacuation from a room with consideration of obstacle removal. The room has one or more exits, one of which is blocked by obstacles. The obstacles at the exit can be removed by volunteers. We investigate the cooperative and defective behaviors of pedestrians during evacuation. The yielder game and volunteer's dilemma game are employed to resolve interpedestrian conflict. An anticipation floor field is proposed to guide the pedestrians to avoid obstacles that are being removed. We conducted experiments to determine how a variety of conditions affect overall crowd evacuation and volunteer evacuation times. The conditions were the start time of obstacle removal, number of obstacles, placement of obstacles, time spent in obstacle removal, strength of the anticipation floor field, and obstacle visibility distance. We demonstrate how reciprocity can be achieved among pedestrians and increases the efficiency of the entire evacuation process.

Neuromorphic Kalman filter implementation in IBM’s TrueNorth

NASA Astrophysics Data System (ADS)

Carney, R.; Bouchard, K.; Calafiura, P.; Clark, D.; Donofrio, D.; Garcia-Sciveres, M.; Livezey, J.

2017-10-01

Following the advent of a post-Moore’s law field of computation, novel architectures continue to emerge. With composite, multi-million connection neuromorphic chips like IBM’s TrueNorth, neural engineering has now become a feasible technology in this novel computing paradigm. High Energy Physics experiments are continuously exploring new methods of computation and data handling, including neuromorphic, to support the growing challenges of the field and be prepared for future commodity computing trends. This work details the first instance of a Kalman filter implementation in IBM’s neuromorphic architecture, TrueNorth, for both parallel and serial spike trains. The implementation is tested on multiple simulated systems and its performance is evaluated with respect to an equivalent non-spiking Kalman filter. The limits of the implementation are explored whilst varying the size of weight and threshold registers, the number of spikes used to encode a state, size of neuron block for spatial encoding, and neuron potential reset schemes.

Stability of the discretization of the electron avalanche phenomenon

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

Villa, Andrea, E-mail: andrea.villa@rse-web.it; Barbieri, Luca, E-mail: luca.barbieri@rse-web.it; Gondola, Marco, E-mail: marco.gondola@rse-web.it

2015-09-01

The numerical simulation of the discharge inception is an active field of applied physics with many industrial applications. In this work we focus on the drift-reaction equation that describes the electron avalanche. This phenomenon is one of the basic building blocks of the streamer model. The main difficulty of the electron avalanche equation lies in the fact that the reaction term is positive when a high electric field is applied. It leads to exponentially growing solutions and this has a major impact on the behavior of numerical schemes. We analyze the stability of a reference finite volume scheme applied tomore » this latter problem. The stability of the method may impose a strict mesh spacing, therefore a proper stabilized scheme, which is stable whatever spacing is used, has been developed. The convergence of the scheme is treated as well as some numerical experiments.« less

Breaking the icosahedra in boron carbide

PubMed Central

Xie, Kelvin Y.; An, Qi; Sato, Takanori; Breen, Andrew J.; Ringer, Simon P.; Goddard, William A.; Cairney, Julie M.; Hemker, Kevin J.

2016-01-01

Findings of laser-assisted atom probe tomography experiments on boron carbide elucidate an approach for characterizing the atomic structure and interatomic bonding of molecules associated with extraordinary structural stability. The discovery of crystallographic planes in these boron carbide datasets substantiates that crystallinity is maintained to the point of field evaporation, and characterization of individual ionization events gives unexpected evidence of the destruction of individual icosahedra. Statistical analyses of the ions created during the field evaporation process have been used to deduce relative atomic bond strengths and show that the icosahedra in boron carbide are not as stable as anticipated. Combined with quantum mechanics simulations, this result provides insight into the structural instability and amorphization of boron carbide. The temporal, spatial, and compositional information provided by atom probe tomography makes it a unique platform for elucidating the relative stability and interactions of primary building blocks in hierarchically crystalline materials. PMID:27790982

A three-sided rearrangeable switching network for a binary fat tree

NASA Astrophysics Data System (ADS)

Yen, Mao-Hsu; Yu, Chu; Shin, Haw-Yun; Chen, Sao-Jie

2011-06-01

A binary fat tree needs an internal node to interconnect the left-children, right-children and parent terminals to each other. In this article, we first propose a three-stage, 3-sided rearrangeable switching network for the implementation of a binary fat tree. The main component of this 3-sided switching network (3SSN) consists of a polygonal switch block (PSB) interconnected by crossbars. With the same size and the same number of switches as our 3SSN, a three-stage, 3-sided clique-based switching network is shown to be not rearrangeable. Also, the effects of the rearrangeable structure and the number of terminals on the network switch-efficiency are explored and a proper set of parameters has been determined to minimise the number of switches. We derive that a rearrangeable 3-sided switching network with switches proportional to N 3/2 is most suitable to interconnect N terminals. Moreover, we propose a new Polygonal Field Programmable Gate Array (PFPGA) that consists of logic blocks interconnected by our 3SSN, such that the logic blocks in this PFPGA can be grouped into clusters to implement different logic functions. Since the programmable switches usually have high resistance and capacitance and occupy a large area, we have to consider the effect of the 3SSN structure and the granularity of its cluster logic blocks on the switch efficiency of PFPGA. Experiments on benchmark circuits show that the switch and speed performances are significantly improved. Based on the experimental results, we can determine the parameters of PFPGA for the VLSI implementation.

WWC Quick Review of the Report "The Role of Simplification and Information in College Decisions: Results from the H&R Block FAFSA Experiment" Revised

ERIC Educational Resources Information Center

What Works Clearinghouse, 2010

2010-01-01

This paper presents an updated WWC (What Works Clearinghouse) Quick Review of the report "The Role of Simplification and Information in College Decisions: Results from the H&R Block FAFSA Experiment". The study examined whether assistance in filling out the Free Application for Federal Student Aid (FAFSA) increases the likelihood of…

WWC Quick Review of the Report "The Role of Simplification and Information in College Decisions: Results from the H&R Block FAFSA Experiment"

ERIC Educational Resources Information Center

What Works Clearinghouse, 2010

2010-01-01

This paper presents a WWC (What Works Clearinghouse) Quick Review of the report "The Role of Simplification and Information in College Decisions: Results from the H&R Block FAFSA Experiment". The study examined whether assistance in filling out the Free Application for Federal Student Aid (FAFSA) increases the likelihood of filing…

Microphase separation in random multiblock copolymers

NASA Astrophysics Data System (ADS)

Govorun, E. N.; Chertovich, A. V.

2017-01-01

Microphase separation in random multiblock copolymers is studied with the mean-field theory assuming that long blocks of a copolymer are strongly segregated, whereas short blocks are able to penetrate into "alien" domains and exchange between the domains and interfacial layer. A bidisperse copolymer with blocks of only two sizes (long and short) is considered as a model of multiblock copolymers with high polydispersity in the block size. Short blocks of the copolymer play an important role in the microphase separation. First, their penetration into the "alien" domains leads to the formation of joint long blocks in their own domains. Second, short blocks localized at the interface considerably change the interfacial tension. The possibility of penetration of short blocks into the "alien" domains is controlled by the product χ Nsh (χ is the Flory-Huggins interaction parameter and Nsh is the short block length). At not very large χ Nsh , the domain size is larger than that for a regular copolymer consisting of the same long blocks as in the considered random copolymer. At a fixed mean block size, the domain size grows with an increase in the block size dispersity, the rate of the growth being dependent of the more detailed parameters of the block size distribution.

Investigating Perfect Timesharing: The Relationship between IM-Compatible Tasks and Dual-Task Performance

ERIC Educational Resources Information Center

Halvorson, Kimberly M.; Ebner, Herschel; Hazeltine, Eliot

2013-01-01

Why are dual-task costs reduced with ideomotor (IM) compatible tasks (Greenwald & Shulman, 1973; Lien, Proctor & Allen, 2002)? In the present experiments, we first examine three different measures of single-task performance (pure single-task blocks, mixed blocks, and long stimulus onset asynchrony [SOA] trials in dual-task blocks) and two…

The Effect of a Commercial Game on Children's Block Design Scores on the WISC-R IQ Test.

ERIC Educational Resources Information Center

Dirks, Jean

1982-01-01

Relatively brief interactions with a commercial game that involved blocks and matching patterns are shown to cause a significant improvement in children's performances on the WISC-R Block Design subtest. Two experiments are described using 10-year-old children in game and no-game conditions. (Author/CM)

Similarity in Spatial Origin of Information Facilitates Cue Competition and Interference

ERIC Educational Resources Information Center

Amundson, Jeffrey C.; Miller, Ralph R.

2007-01-01

Two lick suppression studies were conducted with water-deprived rats to investigate the influence of spatial similarity in cue interaction. Experiment 1 assessed the influence of similarity of the spatial origin of competing cues in a blocking procedure. Greater blocking was observed in the condition in which the auditory blocking cue and the…

The experimental design of the Missouri Ozark Forest Ecosystem Project

Treesearch

Steven L. Sheriff; Shuoqiong He

1997-01-01

The Missouri Ozark Forest Ecosystem Project (MOFEP) is an experiment that examines the effects of three forest management practices on the forest community. MOFEP is designed as a randomized complete block design using nine sites divided into three blocks. Treatments of uneven-aged, even-aged, and no-harvest management were randomly assigned to sites within each block...

Spatial distribution of block falls using volumetric GIS-decision-tree models

NASA Astrophysics Data System (ADS)

Abdallah, C.

2010-10-01

Block falls are considered a significant aspect of surficial instability contributing to losses in land and socio-economic aspects through their damaging effects to natural and human environments. This paper predicts and maps the geographic distribution and volumes of block falls in central Lebanon using remote sensing, geographic information systems (GIS) and decision-tree modeling (un-pruned and pruned trees). Eleven terrain parameters (lithology, proximity to fault line, karst type, soil type, distance to drainage line, elevation, slope gradient, slope aspect, slope curvature, land cover/use, and proximity to roads) were generated to statistically explain the occurrence of block falls. The latter were discriminated using SPOT4 satellite imageries, and their dimensions were determined during field surveys. The un-pruned tree model based on all considered parameters explained 86% of the variability in field block fall measurements. Once pruned, it classifies 50% in block falls' volumes by selecting just four parameters (lithology, slope gradient, soil type, and land cover/use). Both tree models (un-pruned and pruned) were converted to quantitative 1:50,000 block falls' maps with different classes; starting from Nil (no block falls) to more than 4000 m 3. These maps are fairly matching with coincidence value equal to 45%; however, both can be used to prioritize the choice of specific zones for further measurement and modeling, as well as for land-use management. The proposed tree models are relatively simple, and may also be applied to other areas (i.e. the choice of un-pruned or pruned model is related to the availability of terrain parameters in a given area).

Isoelectric Bovine Serum Albumin: Robust Blocking Agent for Enhanced Performance in Optical-Fiber Based DNA Sensing.

PubMed

Wang, Ruoyu; Zhou, Xiaohong; Zhu, Xiyu; Yang, Chao; Liu, Lanhua; Shi, Hanchang

2017-02-24

Surface blocking is a well-known process for reducing unwanted nonspecific adsorption in sensor fabrication, especially important in the emerging field where DNA/RNA applied. Bovine serum albumin (BSA) is one of the most popular blocking agents with an isoelectric point at pH 4.6. Although it is widely recognized that the adsorption of a blocking agent is strongly affected by its net charge and the maximum adsorption is often observed under its isoelectric form, BSA has long been perfunctorily used for blocking merely in neutral solution, showing poor blocking performances in the optical-fiber evanescent wave (OFEW) based sensing toward DNA target. To meet this challenge, we first put forward the view that isoelectric BSA (iep-BSA) has the best blocking performance and use an OFEW sensor platform to demonstrate this concept. An optical-fiber was covalently modified with amino-DNA, and further coupled with the optical system to detect fluorophore labeled complementary DNA within the evanescent field. A dramatic improvement in the reusability of this DNA modified sensing surface was achieved with 120 stable detection cycles, which ensured accurate quantitative bioassay. As expected, the iep-BSA blocked OFEW system showed enhanced sensing performance toward target DNA with a detection limit of 125 pM. To the best of our knowledge, this is the highest number of regeneration cycles ever reported for a DNA immobilized optical-fiber surface. This study can also serve as a good reference and provide important implications for developing similar DNA-directed surface biosensors.

Stress Coupling Relationship between Mantle Convection and Seismogenic Layer in Southeastern Tibetan Plateau and its Geodynamic Implications

NASA Astrophysics Data System (ADS)

Qiang, H.

2015-12-01

The lithospheric stress states and interlayer coupling interaction is of great significant in studying plate driven mechanism and seismogenic environment. The coupling relationship between mantle convection generated drag stress in the lithospheric base and seismogenic layer stress in the crust represents the lithospheric mechanical coupling intensity level. We calculate the lithospheric bottom mantle convection stress field of the southeastern Tibetan Plateau using 11~36 spherical harmonic coefficients of gravity model EGM2008. Meanwhile we collect and organize the focal mechanism of 1131 earthquakes that occurred from 2000 to now in Sichuan-Yunnan region. The current seismogenic layer stress and stress field before Lushan earthquake are calculated by the damping regional stress tensor inversion. We further analyze the correlation between the two kinds of stress fields, then discuss the relation between mechanics coupling situation and strong earthquakes in different regions. The results show that: (1) Most of Sichuan-Yunnan region is located in the coupling and decoupling intermediate zone. Coupling zones distribute on the basis of block, the eastern South China block has strong coupling, and the coupling phenomenon also exists in parts of the northern Tibet block, Balyanlkalla block in the northwest and southwest Yunnan block. The decoupling mainly occurs in Songpan-Ganzi block, connecting with the strong coupling South China block and Longmenshan fault zone is their boundary. (2) We have analyzed seismogenic mechanism, then proposed the border zone of strong and weak coupling relation between mantle convection stress and seismogenic layer stress exists high seismic risk. The current coupling situation shows that Longmenshan fault zone is still in the large varying gradient area of coupling intensity level, it has conditions to accumulate energy and develop earthquakes. Other dangerous areas are: Mingjiang, Xianshuihe, Anninghe, Zemuhe, the Red River, Nantinghe fault zone and their neighboring areas.

Controlling sub-microdomain structure in microphase-ordered block copolymers and their nanocomposites

NASA Astrophysics Data System (ADS)

Bowman, Michelle Kathleen

Block copolymers exhibit a wealth of morphologies that continue to find ubiquitous use in a diverse variety of mature and emergent (nano)technologies, such as photonic crystals, integrated circuits, pharmaceutical encapsulents, fuel cells and separation membranes. While numerous studies have explored the effects of molecular confinement on such copolymers, relatively few have examined the sub-microdomain structure that develops upon modification of copolymer molecular architecture or physical incorporation of nanoscale objects. This work will address two relevant topics in this vein: (i) bidisperse brushes formed by single block copolymer molecules and (ii) copolymer nanocomposites formed by addition of molecular or nanoscale additives. In the first case, an isomorphic series of asymmetric poly(styrene-b -isoprene-b-styrene) (S1IS2) triblock copolymers of systematically varied chain length has been synthesized from a parent SI diblock copolymer. Small-angle x-ray scattering, coupled with dynamic rheology and self-consistent field theory (SCFT), reveals that the progressively grown S2 block initially resides in the I-rich matrix and effectively reduces the copolymer incompatibility until a critical length is reached. At this length, the S2 block co-locates with the S1 block so that the two blocks generate a bidisperse brush (insofar as the S1 and S2 lengths differ). This single-molecule analog to binary block copolymer blends affords unique opportunities for materials design at sub-microdomain length scales and provides insight into the transition from diblock to triblock copolymer (and thermoplastic elastomeric nature). In the second case, I explore the distribution of molecular and nanoscale additives in microphase-ordered block copolymers and demonstrate via SCFT that an interfacial excess, which depends strongly on additive concentration, selectivity and relative size, develops. These predictions are in agreement with experimental findings. Moreover, using a poly(styrene-b-methyl methacrylate) (SM) diblock copolymer with an order-disorder transition temperature (TODT) of 186°C, we find that the addition of clustered and discrete nanoparticles of varying size and surface selectivity can cause T ODT to generally decrease, but occasionally increase. Also experimenting with a poly(styrene-b-isoprene) (SI) diblock copolymer with an TODT of 116°C, we find that the addition of smaller nanoparticles at small volume fractions effect the TODT more profoundly. The latter unexpected results are likewise predicted by SCFT and provide a unique strategy by which to improve the nanostructure stability of block copolymers by physical means.

Electrical imaging at the large block test—Yucca Mountain, Nevada

NASA Astrophysics Data System (ADS)

Ramirez, A.; Daily, W.

2001-02-01

A monolithic block of densely welded tuff was excavated from a site on Fran Ridge near Yucca Mountain, Nevada so that coupled thermohydrological processes could be studied in a controlled, in situ experiment. A series of heaters were placed in a horizontal plane about 3 m from the top of the 3 m×3 m×4.5-m high block. Temperatures were measured at many points within and on the block surface and a suite of other measurements were taken to define the thermal and hydrologic response. Electrical resistance tomography (ERT) was used to map two-dimensional images of moisture content changes along four planes in the block. The ERT images clearly delineate the drying and wetting of the rockmass during the 13 months of heating and subsequent 6 months of cool down. The main feature is a prominent dry zone that forms around the heaters then gradually disappears as the rock cools down. Other features include linear anomalies of decreasing moisture content, which are fractures dehydrating as the block heats up. There are also examples of compact anomalies of wetting. Some of these appear to be water accumulation in fractures, which are draining condensate from the block. Others may be rainwater entering a fracture at the top of the block. During cool-down, a general rewetting is observed although this is less certain because of poor data quality during this stage of the experiment.

A parallel computer implementation of fast low-rank QR approximation of the Biot-Savart law

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

White, D A; Fasenfest, B J; Stowell, M L

2005-11-07

In this paper we present a low-rank QR method for evaluating the discrete Biot-Savart law on parallel computers. It is assumed that the known current density and the unknown magnetic field are both expressed in a finite element expansion, and we wish to compute the degrees-of-freedom (DOF) in the basis function expansion of the magnetic field. The matrix that maps the current DOF to the field DOF is full, but if the spatial domain is properly partitioned the matrix can be written as a block matrix, with blocks representing distant interactions being low rank and having a compressed QR representation.more » The matrix partitioning is determined by the number of processors, the rank of each block (i.e. the compression) is determined by the specific geometry and is computed dynamically. In this paper we provide the algorithmic details and present computational results for large-scale computations.« less

Opioid receptors mediate direct predictive fear learning: evidence from one-trial blocking.

PubMed

Cole, Sindy; McNally, Gavan P

2007-04-01

Pavlovian fear learning depends on predictive error, so that fear learning occurs when the actual outcome of a conditioning trial exceeds the expected outcome. Previous research has shown that opioid receptors, including mu-opioid receptors in the ventrolateral quadrant of the midbrain periaqueductal gray (vlPAG), mediate such predictive fear learning. Four experiments reported here used a within-subject one-trial blocking design to study whether opioid receptors mediate a direct or indirect action of predictive error on Pavlovian association formation. In Stage I, rats were trained to fear conditioned stimulus (CS) A by pairing it with shock. In Stage II, CSA and CSB were co-presented once and co-terminated with shock. Two novel stimuli, CSC and CSD, were also co-presented once and co-terminated with shock in Stage II. The results showed one-trial blocking of fear learning (Experiment 1) as well as one-trial unblocking of fear learning when Stage II training employed a higher intensity footshock than was used in Stage I (Experiment 2). Systemic administrations of the opioid receptor antagonist naloxone (Experiment 3) or intra-vlPAG administrations of the selective mu-opioid receptor antagonist CTAP (Experiment 4) prior to Stage II training prevented one-trial blocking. These results show that opioid receptors mediate the direct actions of predictive error on Pavlovian association formation.

Electrostatically screened, voltage-controlled electrostatic chuck

DOEpatents

Klebanoff, Leonard Elliott

2001-01-01

Employing an electrostatically screened, voltage-controlled electrostatic chuck particularly suited for holding wafers and masks in sub-atmospheric operations will significantly reduce the likelihood of contaminant deposition on the substrates. The electrostatic chuck includes (1) an insulator block having a outer perimeter and a planar surface adapted to support the substrate and comprising at least one electrode (typically a pair of electrodes that are embedded in the insulator block), (2) a source of voltage that is connected to the at least one electrode, (3) a support base to which the insulator block is attached, and (4) a primary electrostatic shield ring member that is positioned around the outer perimeter of the insulator block. The electrostatic chuck permits control of the voltage of the lithographic substrate; in addition, it provides electrostatic shielding of the stray electric fields issuing from the sides of the electrostatic chuck. The shielding effectively prevents electric fields from wrapping around to the upper or front surface of the substrate, thereby eliminating electrostatic particle deposition.

Conformation of single block copolymer chain in two-dimensional microphase-separated structure studied by scanning near-field optical microscopy.

PubMed

Sekine, Ryojun; Aoki, Hiroyuki; Ito, Shinzaburo

2009-05-21

The localization and orientation of the symmetric diblock copolymer chain in a quasi-two-dimensional microphase-separated structure were studied by scanning near-field optical microscopy (SNOM). In the monolayer of poly(isobutyl methacrylate)-block-poly(octadecyl methacrylate) (PiBMA-b-PODMA), the individual PiBMA subchains were directly observed by SNOM, and the center of mass (CM) and orientational angle relative to the phase interface were examined at the single chain level. It was found that the position of the CM and the orientation of the PiBMA subchain in the lamellar structure were dependent on the curvature of the PiBMA/PODMA interface. As the interface was bent toward the objective chain, the block chain preferred the CM position closer to the domain center, and the conformation was strongly oriented perpendicularly to the domain interface. With increase of the curvature, the steric hindrance among the block chain increases, resulting in the stretched conformation.

Repair, Evaluation, Maintenance, and Rehabilitation Research Program: Case Histories of Corps Breakwater and Jetty Structures. Report 5. North Atlantic Division

DTIC Science & Technology

1988-11-01

TERMS (Continue on reverse if necessary and identify by block number) FIELD GROUP SUB-GROUP Breakwater REMR (Repair, Evaluation, Concrete armor units...Maintenance, and Rehabilitation) Jetty Rubble-mound structures 19. ABSTRACT (Continue on reverse if necessary and identify by block number) :-This...have been repaired since construction. Other construction materials that have been used include steel, dolosse, concrete cap, concrete block , and

Modeling and Simulation of a Non-Coherent Frequency Shift Keying Transceiver Using a Field Programmable Gate Array (FPGA)

DTIC Science & Technology

2008-09-01

Convolutional Encoder Block Diagram of code rate 1 2 r = and...most commonly used along with block codes . They were introduced in 1955 by Elias [7]. Convolutional codes are characterized by the code rate kr n... convolutional code for 1 2 r = and = 3κ , namely [7 5], is used. Figure 2 Convolutional Encoder Block Diagram of code rate 1 2 r = and

Restricted lithium ion dynamics in PEO-based block copolymer electrolytes measured by high-field nuclear magnetic resonance relaxation

NASA Astrophysics Data System (ADS)

Huynh, Tan Vu; Messinger, Robert J.; Sarou-Kanian, Vincent; Fayon, Franck; Bouchet, Renaud; Deschamps, Michaël

2017-10-01

The intrinsic ionic conductivity of polyethylene oxide (PEO)-based block copolymer electrolytes is often assumed to be identical to the conductivity of the PEO homopolymer. Here, we use high-field 7Li nuclear magnetic resonance (NMR) relaxation and pulsed-field-gradient (PFG) NMR diffusion measurements to probe lithium ion dynamics over nanosecond and millisecond time scales in PEO and polystyrene (PS)-b-PEO-b-PS electrolytes containing the lithium salt LiTFSI. Variable-temperature longitudinal (T1) and transverse (T2) 7Li NMR relaxation rates were acquired at three magnetic field strengths and quantitatively analyzed for the first time at such fields, enabling us to distinguish two characteristic time scales that describe fluctuations of the 7Li nuclear electric quadrupolar interaction. Fast lithium motions [up to O (ns)] are essentially identical between the two polymer electrolytes, including sub-nanosecond vibrations and local fluctuations of the coordination polyhedra between lithium and nearby oxygen atoms. However, lithium dynamics over longer time scales [O (10 ns) and greater] are slower in the block copolymer compared to the homopolymer, as manifested experimentally by their different transverse 7Li NMR relaxation rates. Restricted dynamics and altered thermodynamic behavior of PEO chains anchored near PS domains likely explain these results.

A new dry hypothesis for the formation of Martian linear gullies

USGS Publications Warehouse

Diniega, Serina; Hansen, Candice J.; McElwaine, Jim N.; Hugenholtz, C.H.; Dundas, Colin M.; McEwen, Alfred S.; Bourke, Mary C.

2013-01-01

Long, narrow grooves found on the slopes of martian sand dunes have been cited as evidence of liquid water via the hypothesis that melt-water initiated debris flows eroded channels and deposited lateral levées. However, this theory has several short-comings for explaining the observed morphology and activity of these linear gullies. We present an alternative hypothesis that is consistent with the observed morphology, location, and current activity: that blocks of CO2 ice break from over-steepened cornices as sublimation processes destabilize the surface in the spring, and these blocks move downslope, carving out levéed grooves of relatively uniform width and forming terminal pits. To test this hypothesis, we describe experiments involving water and CO2 blocks on terrestrial dunes and then compare results with the martian features. Furthermore, we present a theoretical model of the initiation of block motion due to sublimation and use this to quantitatively compare the expected behavior of blocks on the Earth and Mars. The model demonstrates that CO2 blocks can be expected to move via our proposed mechanism on the Earth and Mars, and the experiments show that the motion of these blocks will naturally create the main morphological features of linear gullies seen on Mars.

Advanced methods for displays and remote control of robots.

PubMed

Eliav, Ami; Lavie, Talia; Parmet, Yisrael; Stern, Helman; Edan, Yael

2011-11-01

An in-depth evaluation of the usability and situation awareness performance of different displays and destination controls of robots are presented. In two experiments we evaluate the way information is presented to the operator and assess different means for controlling the robot. Our study compares three types of displays: a "blocks" display, a HUD (head-up display), and a radar display, and two types of controls: touch screen and hand gestures. The HUD demonstrated better performance when compared to the blocks display and was perceived to have greater usability compared to the radar display. The HUD was also found to be more useful when the operation of the robot was more difficult, i.e., when using the hand-gesture method. The experiments also pointed to the importance of using a wide viewing angle to minimize distortion and for easier coping with the difficulties of locating objects in the field of view margins. The touch screen was found to be superior in terms of both objective performance and its perceived usability. No differences were found between the displays and the controllers in terms of situation awareness. This research sheds light on the preferred display type and controlling method for operating robots from a distance, making it easier to cope with the challenges of operating such systems. Copyright © 2011 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Bipolar radiofrequency ablation with 2 × 2 electrodes as a building block for matrix radiofrequency ablation: Ex vivo liver experiments and finite element method modelling.

PubMed

Mulier, Stefaan; Jiang, Yansheng; Jamart, Jacques; Wang, Chong; Feng, Yuanbo; Marchal, Guy; Michel, Luc; Ni, Yicheng

2015-01-01

Size and geometry of the ablation zone obtained by currently available radiofrequency (RF) electrodes is highly variable. Reliability might be improved by matrix radiofrequency ablation (MRFA), in which the whole tumour volume is contained within a cage of x × y parallel electrodes. The aim of this study was to optimise the smallest building block for matrix radiofrequency ablation: a recently developed bipolar 2 × 2 electrode system. In ex vivo bovine liver, the parameters of the experimental set-up were changed one by one. In a second step, a finite element method (FEM) modelling of the experiment was performed to better understand the experimental findings. The optimal power to obtain complete ablation in the shortest time was 50-60 W. Performing an ablation until impedance rise was superior to ablation for a fixed duration. Increasing electrode diameter improved completeness of ablation due to lower temperature along the electrodes. A chessboard pattern of electrode polarity was inferior to a row pattern due to an electric field void in between the electrodes. Variability of ablation size was limited. The FEM correctly simulated and explained the findings in ex vivo liver. These experiments and FEM modelling allowed a better insight in the factors influencing the ablation zone in a bipolar 2 × 2 electrode RF system. With optimal parameters, complete ablation was obtained quickly and with limited variability. This knowledge will be useful to build a larger system with x × y electrodes for MRFA.

False fame prevented: avoiding fluency effects without judgmental correction.

PubMed

Topolinski, Sascha; Strack, Fritz

2010-05-01

Three studies show a way to prevent fluency effects independently of judgmental correction strategies by identifying and procedurally blocking the sources of fluency variations, which are assumed to be embodied in nature. For verbal stimuli, covert pronunciations are assumed to be the crucial source of fluency gains. As a consequence, blocking such pronunciation simulations through a secondary oral motor task decreased the false-fame effect for repeatedly presented names of actors (Experiment 1) as well as prevented increases in trust due to repetition for brand names and names of shares in the stock market (Experiment 2). Extending this evidence beyond repeated exposure, we demonstrated that blocking oral motor simulations also prevented fluency effects of word pronunciation on judgments of hazardousness (Experiment 3). Concerning the realm of judgment correction, this procedural blocking of (biasing) associative processes is a decontamination method not considered before in the literature, because it is independent of exposure control, mood, motivation, and post hoc correction strategies. The present results also have implications for applied issues, such as advertising and investment decisions. 2010 APA, all rights reserved

Retardation of mobile radionuclides in granitic rock fractures by matrix diffusion

NASA Astrophysics Data System (ADS)

Hölttä, P.; Poteri, A.; Siitari-Kauppi, M.; Huittinen, N.

Transport of iodide and sodium has been studied by means of block fracture and core column experiments to evaluate the simplified radionuclide transport concept. The objectives were to examine the processes causing retention in solute transport, especially matrix diffusion, and to estimate their importance during transport in different scales and flow conditions. Block experiments were performed using a Kuru Grey granite block having a horizontally planar natural fracture. Core columns were constructed from cores drilled orthogonal to the fracture of the granite block. Several tracer tests were performed using uranine, 131I and 22Na as tracers at water flow rates 0.7-50 μL min -1. Transport of tracers was modelled by applying the advection-dispersion model based on the generalized Taylor dispersion added with matrix diffusion. Scoping calculations were combined with experiments to test the model concepts. Two different experimental configurations could be modelled applying consistent transport processes and parameters. The processes, advection-dispersion and matrix diffusion, were conceptualized with sufficient accuracy to replicate the experimental results. The effects of matrix diffusion were demonstrated on the slightly sorbing sodium and mobile iodine breakthrough curves.

Weight shifting operators and conformal blocks

NASA Astrophysics Data System (ADS)

Karateev, Denis; Kravchuk, Petr; Simmons-Duffin, David

2018-02-01

We introduce a large class of conformally-covariant differential operators and a crossing equation that they obey. Together, these tools dramatically simplify calculations involving operators with spin in conformal field theories. As an application, we derive a formula for a general conformal block (with arbitrary internal and external representations) in terms of derivatives of blocks for external scalars. In particular, our formula gives new expressions for "seed conformal blocks" in 3d and 4d CFTs. We also find simple derivations of identities between external-scalar blocks with different dimensions and internal spins. We comment on additional applications, including deriving recursion relations for general conformal blocks, reducing inversion formulae for spinning operators to inversion formulae for scalars, and deriving identities between general 6 j symbols (Racah-Wigner coefficients/"crossing kernels") of the conformal group.

Thermal blocking of preheating

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

Lerner, Rose; Tranberg, Anders, E-mail: rose.lerner@desy.de, E-mail: anders.tranberg@uis.no

2015-04-01

The parametric resonance responsible for preheating after inflation will end when self-interactions of the resonating field and interactions of this field with secondary degrees of freedom become important. In many cases, the effect may be quantified in terms of an effective mass and the resulting shifting out of the spectrum of the strongest resonance band. In certain curvaton models, such thermal blocking can even occur before preheating has begun, delaying or even preventing the decay of the curvaton. We investigate numerically to what extent this thermal blocking is realised in a specific scenario, and whether the effective mass is wellmore » approximated by the perturbative leading order thermal mass. We find that the qualitative behaviour is well reproduced in this approximation, and that the end of preheating can be confidently estimated.« less

Magnetic-field-induced DNA strand breaks in brain cells of the rat.

PubMed Central

Lai, Henry; Singh, Narendra P

2004-01-01

In previous research, we found that rats acutely (2 hr) exposed to a 60-Hz sinusoidal magnetic field at intensities of 0.1-0.5 millitesla (mT) showed increases in DNA single- and double-strand breaks in their brain cells. Further research showed that these effects could be blocked by pretreating the rats with the free radical scavengers melatonin and N-tert-butyl-alpha-phenylnitrone, suggesting the involvement of free radicals. In the present study, effects of magnetic field exposure on brain cell DNA in the rat were further investigated. Exposure to a 60-Hz magnetic field at 0.01 mT for 24 hr caused a significant increase in DNA single- and double-strand breaks. Prolonging the exposure to 48 hr caused a larger increase. This indicates that the effect is cumulative. In addition, treatment with Trolox (a vitamin E analog) or 7-nitroindazole (a nitric oxide synthase inhibitor) blocked magnetic-field-induced DNA strand breaks. These data further support a role of free radicals on the effects of magnetic fields. Treatment with the iron chelator deferiprone also blocked the effects of magnetic fields on brain cell DNA, suggesting the involvement of iron. Acute magnetic field exposure increased apoptosis and necrosis of brain cells in the rat. We hypothesize that exposure to a 60-Hz magnetic field initiates an iron-mediated process (e.g., the Fenton reaction) that increases free radical formation in brain cells, leading to DNA strand breaks and cell death. This hypothesis could have an important implication for the possible health effects associated with exposure to extremely low-frequency magnetic fields in the public and occupational environments. PMID:15121512

Why is Light Text Harder to Read Than Dark Text?

NASA Technical Reports Server (NTRS)

Scharff, Lauren V.; Ahumada, Albert J.

2005-01-01

Scharff and Ahumada (2002, 2003) measured text legibility for light text and dark text. For paragraph readability and letter identification, responses to light text were slower and less accurate for a given contrast. Was this polarity effect (1) an artifact of our apparatus, (2) a physiological difference in the separate pathways for positive and negative contrast or (3) the result of increased experience with dark text on light backgrounds? To rule out the apparatus-artifact hypothesis, all data were collected on one monitor. Its luminance was measured at all levels used, and the spatial effects of the monitor were reduced by pixel doubling and quadrupling (increasing the viewing distance to maintain constant angular size). Luminances of vertical and horizontal square-wave gratings were compared to assess display speed effects. They existed, even for 4-pixel-wide bars. Tests for polarity asymmetries in display speed were negative. Increased experience might develop full letter templates for dark text, while recognition of light letters is based on component features. Earlier, an observer ran all conditions at one polarity and then switched. If dark and light letters were intermixed, the observer might use component features on all trials and do worse on the dark letters, reducing the polarity effect. We varied polarity blocking (completely blocked, alternating smaller blocks, and intermixed blocks). Letter identification responses times showed polarity effects at all contrasts and display resolution levels. Observers were also more accurate with higher contrasts and more pixels per degree. Intermixed blocks increased the polarity effect by reducing performance on the light letters, but only if the randomized block occurred prior to the nonrandomized block. Perhaps observers tried to use poorly developed templates, or they did not work as hard on the more difficult items. The experience hypothesis and the physiological gain hypothesis remain viable explanations.

Using the spatial distribution and lithology of ballistic blocks to interpret eruption sequence and dynamics: August 6 2012 Upper Te Maari eruption, New Zealand

NASA Astrophysics Data System (ADS)

Breard, E. C. P.; Lube, G.; Cronin, S. J.; Fitzgerald, R.; Kennedy, B.; Scheu, B.; Montanaro, C.; White, J. D. L.; Tost, M.; Procter, J. N.; Moebis, A.

2014-10-01

The ballistic ejection of blocks during explosive eruptions constitutes a major hazard near active volcanoes. Fields of ballistic clasts can provide important clues towards quantifying the energy, dynamics and directionality of explosive events, but detailed datasets are rare. During the 6 August 2012 hydrothermal eruption of Upper Te Maari (Tongariro), New Zealand, three explosions occurred in rapid succession within less than 20 s. The first two produced laterally-directed pyroclastic density currents (PDC), and the final vertical explosion generated an ash plume. Each of these explosions was associated with the ejection of ballistic blocks. We present detailed maps of the resulting 5.1 km2 block impact field and the distribution of the > 2200 impact craters with diameters > 2.5 m. There are two distinct regions of high crater concentration, where crater densities reach more than six times the average background density. These occur at distances of 500-700 m east and 1000-1350 west of a 430-m-long fissure that was created during the eruption. The high-density fields are characterized by a narrow radial spread of < 45° and are located along the proximal transport direction of the pyroclastic density currents. A provenance analysis of ballistic blocks allowed us to reconstruct two different eruptive vents for the explosions. The first two laterally-directed explosions were sourced from the fissure, while the third explosion occurred through the pre-existing Upper Te Maari Crater, generating a roughly axisymmetric shower of ballistics. Stratigraphic relationships between impact craters, PDC and fall deposits suggest that the ballistic blocks were initially coupled with the rapidly expanding gas-particle mixtures that produced the PDCs. Ballistic trajectory modeling, reproducing the lateral extent and main impact density pattern of the western impact field, allows estimation of the vertical expansion angle of the second and largest explosion. The calculations show that the largest proportion of the explosion energy was strongly focused as a narrow and extremely shallow (from - 3 to 15° from the horizontal) laterally expanding hydrothermal blast. The results presented here constitute an important data set for ballistic hazard assessment at Tongariro volcano and they can provide further clues towards better understanding highly energetic laterally directed volcanic explosions at similar hydrothermal fields.

The Silicon Tracking System of the CBM experiment at FAIR

NASA Astrophysics Data System (ADS)

Teklishyn, Maksym

2018-03-01

The Silicon Tracking System (STS) is the central detector in the Compressed Baryonic Matter (CBM) experiment at FAIR. Operating in the 1Tm dipole magnetic field, the STS will enable pile-up free detection and momentum measurement of the charged particles originating from beam-target nuclear interactions at rates up to 10 MHz. The STS consists of 8 tracking stations based on double-sided silicon micro-strip sensors equipped with fast, self-triggering read-out electronics. With about two million read-out channels, the STS will deliver a high-rate stream of time-stamped data that is transferred to a computing farm for on-line event determination and analysis. The functional building block is a detector module consisting of a sensor, micro-cables and two front-end electronics boards. In this contribution, the development status of the STS components and the system integration is discussed and an outlook on the detector construction is given.

Transport of silver nanoparticles in single fractured sandstone

NASA Astrophysics Data System (ADS)

Neukum, Christoph

2018-02-01

Silver nanoparticles (Ag-NP) are used in various consumer products and are one of the most prevalent metallic nanoparticle in commodities and are released into the environment. Transport behavior of Ag-NP in groundwater is one important aspect for the assessment of environmental impact and protection of drinking water resources in particular. Ag-NP transport processes in saturated single-fractured sandstones using triaxial flow cell experiments with different kind of sandstones is investigated. Ag-NP concentration and size are analyzed using flow field-flow fractionation and coupled SEM-EDX analysis. Results indicate that Ag-NP are more mobile and show generally lower attachment on rock surface compared to experiments in undisturbed sandstone matrix and partially fractured sandstones. Ag-NP transport is controlled by the characteristics of matrix porosity, time depending blocking of attachment sites and solute chemistry. Where Ag-NP attachment occur, it is heterogeneously distributed on the fracture surface.

A novel method to recover DD fusion proton CR-39 data corrupted by fast ablator ions at OMEGA and the National Ignition Facility

NASA Astrophysics Data System (ADS)

Sutcliffe, G. D.; Milanese, L. M.; Orozco, D.; Lahmann, B.; Gatu Johnson, M.; Séguin, F. H.; Sio, H.; Frenje, J. A.; Li, C. K.; Petrasso, R. D.; Park, H.-S.; Rygg, J. R.; Casey, D. T.; Bionta, R.; Turnbull, D. P.; Huntington, C. M.; Ross, J. S.; Zylstra, A. B.; Rosenberg, M. J.; Glebov, V. Yu.

2016-11-01

CR-39 detectors are used routinely in inertial confinement fusion (ICF) experiments as a part of nuclear diagnostics. CR-39 is filtered to stop fast ablator ions which have been accelerated from an ICF implosion due to electric fields caused by laser-plasma interactions. In some experiments, the filtering is insufficient to block these ions and the fusion-product signal tracks are lost in the large background of accelerated ion tracks. A technique for recovering signal in these scenarios has been developed, tested, and implemented successfully. The technique involves removing material from the surface of the CR-39 to a depth beyond the endpoint of the ablator ion tracks. The technique preserves signal magnitude (yield) as well as structure in radiograph images. The technique is effective when signal particle range is at least 10 μm deeper than the necessary bulk material removal.

A novel method to recover DD fusion proton CR-39 data corrupted by fast ablator ions at OMEGA and the National Ignition Facility.

PubMed

Sutcliffe, G D; Milanese, L M; Orozco, D; Lahmann, B; Gatu Johnson, M; Séguin, F H; Sio, H; Frenje, J A; Li, C K; Petrasso, R D; Park, H-S; Rygg, J R; Casey, D T; Bionta, R; Turnbull, D P; Huntington, C M; Ross, J S; Zylstra, A B; Rosenberg, M J; Glebov, V Yu

2016-11-01

CR-39 detectors are used routinely in inertial confinement fusion (ICF) experiments as a part of nuclear diagnostics. CR-39 is filtered to stop fast ablator ions which have been accelerated from an ICF implosion due to electric fields caused by laser-plasma interactions. In some experiments, the filtering is insufficient to block these ions and the fusion-product signal tracks are lost in the large background of accelerated ion tracks. A technique for recovering signal in these scenarios has been developed, tested, and implemented successfully. The technique involves removing material from the surface of the CR-39 to a depth beyond the endpoint of the ablator ion tracks. The technique preserves signal magnitude (yield) as well as structure in radiograph images. The technique is effective when signal particle range is at least 10 μm deeper than the necessary bulk material removal.

An in vitro study of magnetic particle targeting in small blood vessels

NASA Astrophysics Data System (ADS)

Udrea, Laura Elena; Strachan, Norval J. C.; Bădescu, Vasile; Rotariu, Ovidiu

2006-10-01

The magnetic guidance and capture of particles inside the human body, via the circulatory system, is a novel method for the targeted delivery of drugs. This experimental study confirms in vitro that a dipolar capturing device, based on high-energy magnets with an active space of 8.7 cm × 10 cm × 10 cm, retains colloidal magnetic particles (MPs) (<30 nm) injected in the capillary tubes, where flow velocities are comparable to that encountered in the capillary beds of tumours (<0.5 cm s-1). The build-up of the deposition of the MPs was investigated using video imaging techniques that enabled continuous monitoring of the blocking of the vessel whilst simultaneously recording the colloid's flow rate. The parameters of practical importance (length of MP deposit, time of capillary blocking) were estimated and were found to be dependent on the initial fluid velocity, the MP concentration and the distance between the capillary tube and the polar magnetic pieces. Although the tube used in this experiment is larger (diameter = 0.75 mm, length = 100 mm) than that of real capillaries (diameter = 0.01 mm, length ~1.5 mm), the flow velocities chosen were similar to those encountered in the capillary beds of tumours and the length/diameter ratio was approximately equal (133 for the present set-up, 100-150 for real capillaries). In these circumstances and using the same magnetic field conditions (intensity, gradient) and MPs, there is close similarity with magnetic capture in a microscopic capillary system. Moreover, the macroscopic system permits analysis of the distribution of MPs in the active magnetic space, and consequently the maximum targetable volume. This study revealed that the capture of particles within the active space was strongly influenced by the gradient of the magnetic field and the flow velocity. Thus, when the magnetic field gradient had medium values (0.1-0.3 T cm-1) and the fluid velocity was small (0.15 cm s-1), the particles were captured in small, compact and stable deposits (L < 4 cm) and the time necessary for blocking of the capillary was <150 s. Doubling the value for the flow velocity did not influence significantly either the length of MP deposits nor the blocking time. However, lower gradients (<0.1 T cm-1) and larger velocities (0.3-0.9 cm s-1) result in the formation of larger deposits (4 cm < L < 10 cm) that are unstable at the beginning of the capture process. These large deposits do become stable given sufficient time for the deposition process to take place in conjunction with a decrease in the flow rate. As a consequence, the time necessary for blocking of the capillary increased up to 450 s. Decreasing the MP concentration from 0.02 g cm-3 to 0.005 g cm-3 decreased the deposit lengths by approximately 20% and doubled the values of the blocking time. The maximum targetable volume obtained by the present method is ~350 cm3, which corresponds to medium-sized tumours. The capillary vessels were blocked only for the situation that occurs for microcirculation within a tumour. This reduces the concentration of MPs trapped within the normal tissues, which occurs when using particles of micrometre size. This work showed the potential of using colloidal MPs and dipolar magnetic devices for treatment of human patients, when the affected sites are positioned at medium distances from the surface of the body (e.g. head, neck, breast, hands and legs).

Integrated in silico and biological validation of the blocking effect of Cot-1 DNA on Microarray-CGH.

PubMed

Kang, Seung-Hui; Park, Chan Hee; Jeung, Hei Cheul; Kim, Ki-Yeol; Rha, Sun Young; Chung, Hyun Cheol

2007-06-01

In array-CGH, various factors may act as variables influencing the result of experiments. Among them, Cot-1 DNA, which has been used as a repetitive sequence-blocking agent, may become an artifact-inducing factor in BAC array-CGH. To identify the effect of Cot-1 DNA on Microarray-CGH experiments, Cot-1 DNA was labeled directly and Microarray-CGH experiments were performed. The results confirmed that probes which hybridized more completely with Cot-1 DNA had a higher sequence similarity to the Alu element. Further, in the sex-mismatched Microarray-CGH experiments, the variation and intensity in the fluorescent signal were reduced in the high intensity probe group in which probes were better hybridized with Cot-1 DNA. Otherwise, those of the low intensity probe group showed no alterations regardless of Cot-1 DNA. These results confirmed by in silico methods that Cot-1 DNA could block repetitive sequences in gDNA and probes. In addition, it was confirmed biologically that the blocking effect of Cot-1 DNA could be presented via its repetitive sequences, especially Alu elements. Thus, in contrast to BAC-array CGH, the use of Cot-1 DNA is advantageous in controlling experimental variation in Microarray-CGH.

New learning while consolidating memory during sleep is actively blocked by a protein synthesis dependent process

PubMed Central

Levy, Roi; Levitan, David; Susswein, Abraham J

2016-01-01

Brief experiences while a memory is consolidated may capture the consolidation, perhaps producing a maladaptive memory, or may interrupt the consolidation. Since consolidation occurs during sleep, even fleeting experiences when animals are awakened may produce maladaptive long-term memory, or may interrupt consolidation. In a learning paradigm affecting Aplysia feeding, when animals were trained after being awakened from sleep, interactions between new experiences and consolidation were prevented by blocking long-term memory arising from the new experiences. Inhibiting protein synthesis eliminated the block and allowed even a brief, generally ineffective training to produce long-term memory. Memory formation depended on consolidative proteins already expressed before training. After effective training, long term memory required subsequent transcription and translation. Memory formation during the sleep phase was correlated with increased CREB1 transcription, but not CREB2 transcription. Increased C/EBP transcription was a correlate of both effective and ineffective training and of treatments not producing memory. DOI: http://dx.doi.org/10.7554/eLife.17769.001 PMID:27919318

New learning while consolidating memory during sleep is actively blocked by a protein synthesis dependent process.

PubMed

Levy, Roi; Levitan, David; Susswein, Abraham J

2016-12-06

Brief experiences while a memory is consolidated may capture the consolidation, perhaps producing a maladaptive memory, or may interrupt the consolidation. Since consolidation occurs during sleep, even fleeting experiences when animals are awakened may produce maladaptive long-term memory, or may interrupt consolidation. In a learning paradigm affecting Aplysia feeding, when animals were trained after being awakened from sleep, interactions between new experiences and consolidation were prevented by blocking long-term memory arising from the new experiences. Inhibiting protein synthesis eliminated the block and allowed even a brief, generally ineffective training to produce long-term memory. Memory formation depended on consolidative proteins already expressed before training. After effective training, long term memory required subsequent transcription and translation. Memory formation during the sleep phase was correlated with increased CREB1 transcription, but not CREB2 transcription. Increased C/EBP transcription was a correlate of both effective and ineffective training and of treatments not producing memory.

Union Texas hopes to reproduce its Pakistan Badin experience

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

Petzet, G.A.

1997-11-03

Union Texas Petroleum Holdings Inc. has resolved to transplant elsewhere in the world the success of tis 20 year old grass-roots exploration effort on the Badin block in Pakistan. Union Texas Pakistan Inc. (UTP) is actively seeking exploration concessions in Pakistan, and the parent company is on an international bent aimed at finding other areas where it might reproduce its performance in Pakistan. The 104 exploratory wells drilled through April 1, 1997, resulted in 47 discoveries and 57 dry holes for a 45% success rate. Some oil and gas are produced from the Middle Sand units, and some gas ismore » produced from the Basal Sand units. The 1997 Badin exploration plan called for 11 exploratory wells, including one, Tarai Deep-3, that would test a new play concept in Jurassic Chiltan. It also called for Badin`s first 3D seismic surveys, at South Buzdar and Tangri fields on the northern part of the block, and 146 km of 2D seismic acquisition. The paper discusses Badin development, drilling status, operating challenges, oil price and sales, gas markets, local effects, and future developments.« less

Limestone weathering rates accelerated by micron-scale grain detachment

NASA Astrophysics Data System (ADS)

Emmanuel, S.; Levenson, Y.

2014-12-01

The weathering rates of carbonate rocks is often thought to be controlled by chemical dissolution, although some studies have suggested that mechanical erosion could also play an important role. Quantifying the rates of the different processes has proved challenging due to the high degree of variability encountered in both field and lab settings. To determine the rates and mechanisms controlling long-term limestone weathering, we analyse a lidar scan of the Western Wall, a Roman period edifice located in Jerusalem. Weathering rates in fine-grained micritic limestone blocks are up to 2 orders of magnitude higher than the average rates estimated for coarse-grained limestone blocks at the same site. In addition, in experiments that use atomic force microscopy to image dissolving micritic limestone, we show that these higher reaction rates could be due to rapid dissolution along micron-scale grain boundaries, followed by mechanical detachment of tiny particles from the surface. Our analysis indicates that micron-scale grain detachment, rather than pure chemical dissolution, could be the dominant erosional mode for fine-grained rocks in many carbonate terrains.

Extreme limestone weathering rates due to micron-scale grain detachment

NASA Astrophysics Data System (ADS)

Emmanuel, Simon; Levenson, Yael

2014-05-01

Chemical dissolution is often assumed to control the weathering rates of carbonate rocks, although some studies have indicated that mechanical erosion could also play a significant role. Quantifying the rates of the different processes is challenging due to the high degree of variability encountered in both field and lab settings. To measure the rates and mechanisms controlling long-term limestone weathering, we analyse a lidar scan of the Western Wall, a Roman period edifice located in Jerusalem. Surface retreat rates in fine-grained micritic limestone blocks are found to be as much as 2 orders of magnitude higher than the average rates estimated for coarse-grained limestone blocks at the same site. In addition, in experiments that use atomic force microscopy to image dissolving micritic limestone, we show that these elevated reaction rates could be due to rapid dissolution along micron-scale grain boundaries, followed by mechanical detachment of tiny particles from the surface. Our analysis indicates that micron-scale grain detachment, rather than pure chemical dissolution, could be the dominant erosional mode for fine-grained carbonate rocks.

Monte Carlo study of magnetic nanoparticles adsorbed on halloysite Al2Si2O5(OH) 4 nanotubes

NASA Astrophysics Data System (ADS)

Sotnikov, O. M.; Mazurenko, V. V.; Katanin, A. A.

2017-12-01

We study properties of magnetic nanoparticles adsorbed on the halloysite surface. For that a distinct magnetic Hamiltonian with a random distribution of spins on a cylindrical surface was solved by using a nonequilibrium Monte Carlo method. The parameters for our simulations, the anisotropy constant, nanoparticle size distribution, saturated magnetization, and geometrical characteristics of the halloysite template, were taken from recent experiments. We calculate the hysteresis loops and temperature dependence of the zero-field-cooling (ZFC) susceptibility, the maximum of which determines the blocking temperature. It is shown that the dipole-dipole interaction between nanoparticles moderately increases the blocking temperature and weakly increases the coercive force. The obtained hysteresis loops (e.g., the value of the coercive force) for Ni nanoparticles are in reasonable agreement with the experimental data. We also discuss the sensitivity of the hysteresis loops and ZFC susceptibilities to the change in anisotropy and dipole-dipole interaction, as well as the 3 d -shell occupation of the metallic nanoparticles; in particular we predict larger coercive force for Fe than for Ni nanoparticles.

An inhibitor of polyamine synthesis arrests cells at an earlier stage of G1 than does calcium deprivation.

PubMed Central

Cheetham, B F

1983-01-01

Methylglyoxal bis(guanylhydrazone) completely inhibits the induction of thymidine kinase after serum stimulation of quiescent fibroblasts only if added within 3 h after serum, whereas calcium deprivation blocks this induction up to 12 h after serum stimulation. Experiments in which one of these blocks was imposed as the other was released confirmed that cells blocked by methylglyoxal bis(guanylhydrazone) are arrested at an earlier stage in G1 than cells blocked by calcium deprivation. PMID:6843551

How the continents deform: The evidence from tectonic geodesy

USGS Publications Warehouse

Thatcher, Wayne R.

2009-01-01

Space geodesy now provides quantitative maps of the surface velocity field within tectonically active regions, supplying constraints on the spatial distribution of deformation, the forces that drive it, and the brittle and ductile properties of continental lithosphere. Deformation is usefully described as relative motions among elastic blocks and is block-like because major faults are weaker than adjacent intact crust. Despite similarities, continental block kinematics differs from global plate tectonics: blocks are much smaller, typically ∼100–1000 km in size; departures from block rigidity are sometimes measurable; and blocks evolve over ∼1–10 Ma timescales, particularly near their often geometrically irregular boundaries. Quantitatively relating deformation to the forces that drive it requires simplifying assumptions about the strength distribution in the lithosphere. If brittle/elastic crust is strongest, interactions among blocks control the deformation. If ductile lithosphere is the stronger, its flow properties determine the surface deformation, and a continuum approach is preferable.

Development and validation of fuel height models for terrestrial lidar - RxCADRE 2012

Treesearch

Eric M. Rowell; Carl A. Seielstad; Roger D. Ottmar

2016-01-01

Terrestrial laser scanning (TLS) was used to collect spatially continuous measurements of fuelbed characteristics across the plots and burn blocks of the 2012 RxCADRE experiments in Florida. Fuelbeds were scanned obliquely from plot/block edges at a height of 20 m above ground. Pre-fire blocks were scanned from six perspectives and four perspectives for post-...

Effects of electric fields on the photonic crystal formation from block copolymers

NASA Astrophysics Data System (ADS)

Lee, Taekun; Ju, Jin-wook; Ryoo, Won

2012-03-01

Effects of electric fields on the self-assembly of block copolymers have been investigated for thin films of polystyrene-bpoly( 2-vinyl pyridine); PS-b-P2VP, 52 kg/mol-b-57 kg/mol and 133 kg/mol-b-132 kg/mol. Block copolymers of polystyrene and poly(2-vinyl pyridine) have been demonstrated to form photonic crystals of 1D lamellar structure with optical band gaps that correspond to UV-to-visible light. The formation of lamellar structure toward minimum freeenergy state needs increasing polymer chain mobility, and the self-assembly process is accelerated usually by annealing, that is exposing the thin film to solvent vapor such as chloroform and dichloromethane. In this study, thin films of block copolymers were spin-coated on substrates and placed between electrode arrays of various patterns including pin-points, crossing and parallel lines. As direct or alternating currents were applied to electrode arrays during annealing process, the final structure of thin films was altered from the typical 1D lamellae in the absence of electric fields. The formation of lamellar structure was spatially controlled depending on the shape of electrode arrays, and the photonic band gap also could be modulated by electric field strength. The spatial formation of lamellar structure was examined with simulated distribution of electrical potentials by finite difference method (FDM). P2VP layers in self-assembled film were quaternized with methyl iodide vapor, and the remaining lamellar structure was investigated by field emission scanning electron microscope (FESEM). The result of this work is expected to provide ways of fabricating functional structures for display devices utilizing photonic crystal array.

Oxalate contributes to the resistance of Gaillardia grandiflora and Lupinus sericeus to a phytotoxin produced by Centaurea maculosa.

PubMed

Weir, Tiffany L; Bais, Harsh Pal; Stull, Valerie J; Callaway, Ragan M; Thelen, Giles C; Ridenour, Wendy M; Bhamidi, Suresh; Stermitz, Frank R; Vivanco, Jorge M

2006-03-01

Centaurea maculosa Lam. is a noxious weed in western North America that produces a phytotoxin, (+/-)-catechin, which is thought to contribute to its invasiveness. Areas invaded by C. maculosa often result in monocultures of the weed, however; in some areas, North American natives stand their ground against C. maculosa and show varying degrees of resistance to its phytotoxin. Two of these resistant native species, Lupinus sericeus Pursh and Gaillardia grandiflora Van Houtte, were found to secrete increased amounts of oxalate in response to catechin exposure. Mechanistically, we found that oxalate works exogenously by blocking generation of reactive oxygen species in susceptible plants and reducing oxidative damage generated in response to catechin. Furthermore, field experiments show that L. sericeus indirectly facilitates native grasses in grasslands invaded by C. maculosa, and this facilitation can be correlated with the presence of oxalate in soil. Addition of exogenous oxalate to native grasses and Arabidopsis thaliana (L.) Heynh grown in vitro alleviated the phytotoxic effects of catechin, supporting the field experiments and suggesting that root-secreted oxalate may also act as a chemical facilitator for plant species that do not secrete the compound.

Untargeted Metabolomics Strategies—Challenges and Emerging Directions

NASA Astrophysics Data System (ADS)

Schrimpe-Rutledge, Alexandra C.; Codreanu, Simona G.; Sherrod, Stacy D.; McLean, John A.

2016-12-01

Metabolites are building blocks of cellular function. These species are involved in enzyme-catalyzed chemical reactions and are essential for cellular function. Upstream biological disruptions result in a series of metabolomic changes and, as such, the metabolome holds a wealth of information that is thought to be most predictive of phenotype. Uncovering this knowledge is a work in progress. The field of metabolomics is still maturing; the community has leveraged proteomics experience when applicable and developed a range of sample preparation and instrument methodology along with myriad data processing and analysis approaches. Research focuses have now shifted toward a fundamental understanding of the biology responsible for metabolomic changes. There are several types of metabolomics experiments including both targeted and untargeted analyses. While untargeted, hypothesis generating workflows exhibit many valuable attributes, challenges inherent to the approach remain. This Critical Insight comments on these challenges, focusing on the identification process of LC-MS-based untargeted metabolomics studies—specifically in mammalian systems. Biological interpretation of metabolomics data hinges on the ability to accurately identify metabolites. The range of confidence associated with identifications that is often overlooked is reviewed, and opportunities for advancing the metabolomics field are described.

Using the application visualization system to view HALOE three-dimensional satellite data

NASA Technical Reports Server (NTRS)

Luo, Mingzhao; Schiano, Allen V. R.; Russell, James M., III; Gordley, Larry L.; Stone, Kenneth A.; Cicerone, Ralph J.

1995-01-01

The Application Visualization System (AVS) is used to view a three-dimensional data field containing the volume mixing ratios of a chemical species in the middle atmosphere obtained by the Halogen Occultation Experiment (HALOE) aboard the Upper Atmosphere Research Satellite (UARS). Since launch in September 1991, HALOE has been collecting data on approximately 30 sunrise/sunset events in two narrow latitude bands each day. The vertical volume mixing ratio profiles are retrieved for eight species for each event. The accumulated data for approximately 30 days cover most of the globe (limited by sunlit latitudes), and this monthly data block can be described as the volume mixing ratio of a specific species in the atmosphere as a function of latitude, longitude, and height. The data were remapped using linear interpolation for pressure levels and Gaussian weighted binning from sampling locations to a three-dimensional grid. An AVS network is constructed that allows for viewing the three-dimensional field with rendered slices at constant latitudes, longitudes or pressure levels. Discussions are given on the advantages and some disadvantages learned about from experiences applying AVS to visualize HALOE three dimensional data.

Long-term use of nerve block catheters in paediatric patients with cancer related pathologic fractures

PubMed Central

BURGOYNE, L. L.; PEREIRAS, L. A.; BERTANI, L. A.; KADDOUM, R. N.; NEEL, M.; FAUGHNAN, L. G.; ANGHELESCU, D. L.

2013-01-01

SUMMARY We report three cases of children with osteosarcoma and pathologic fractures treated with long-term continuous nerve blocks for preoperative pain control. One patient with a left distal femoral diaphysis fracture had a femoral continuous nerve block catheter for 41 days without complications. Another with a fractured left proximal femoral shaft had three femoral continuous nerve block catheters for 33, 26 and 22 days respectively. The third patient, whose right proximal humerus was fractured, had a brachial plexus continuous nerve block catheter for 36 days without complication. In our experience, prolonged use of continuous nerve block is safe and effective in children with pathologic fractures for preoperative pain control. PMID:22813501

Effect of vermicompost on growth, yield and nutrition status of tomato (Lycopersicum esculentum).

PubMed

Azarmi, Rasool; Ziveh, Parviz Sharifi; Satari, Mohammad Reza

2008-07-15

An experiment was conducted to determine the effects of vermicompost on growth, yield and fruit quality of tomato (Lycopersicum esculentum var. Super Beta) in a field condition. The experiment was a randomized complete block design with four replications. The different rates of vermicompost (0, 5, 10 and 15 t ha(-1)) was incorporated into the top 15 cm of soil. During experiment period, fruits were harvested twice in a week and total yield were recorded for two months. At the end of experiment, growth characteristics such as leaf number, leaf area and shoot dry weights were determined. The results revealed that addition of vermicompost at rate of 15 t ha(-1) significantly (at p < 0.05) increased growth and yield compared to control. Vermicompost with rate of 15 t ha(-1) increased EC of fruit juice and percentage of fruit dry matter up to 30 and 24%, respectively. The content of K, P, Fe and Zn in the plant tissue increased 55, 73, 32 and 36% compared to untreated plots respectively. The result of our experiment showed addition of vermicompost had significant (p < 0.05) positive effects on growth, yield and elemental content of plant as compared to control.

Empirical Assessment of the Mean Block Volume of Rock Masses Intersected by Four Joint Sets

NASA Astrophysics Data System (ADS)

Morelli, Gian Luca

2016-05-01

The estimation of a representative value for the rock block volume ( V b) is of huge interest in rock engineering in regards to rock mass characterization purposes. However, while mathematical relationships to precisely estimate this parameter from the spacing of joints can be found in literature for rock masses intersected by three dominant joint sets, corresponding relationships do not actually exist when more than three sets occur. In these cases, a consistent assessment of V b can only be achieved by directly measuring the dimensions of several representative natural rock blocks in the field or by means of more sophisticated 3D numerical modeling approaches. However, Palmström's empirical relationship based on the volumetric joint count J v and on a block shape factor β is commonly used in the practice, although strictly valid only for rock masses intersected by three joint sets. Starting from these considerations, the present paper is primarily intended to investigate the reliability of a set of empirical relationships linking the block volume with the indexes most commonly used to characterize the degree of jointing in a rock mass (i.e. the J v and the mean value of the joint set spacings) specifically applicable to rock masses intersected by four sets of persistent discontinuities. Based on the analysis of artificial 3D block assemblies generated using the software AutoCAD, the most accurate best-fit regression has been found between the mean block volume (V_{{{{b}}_{{m}} }}) of tested rock mass samples and the geometric mean value of the spacings of the joint sets delimiting blocks; thus, indicating this mean value as a promising parameter for the preliminary characterization of the block size. Tests on field outcrops have demonstrated that the proposed empirical methodology has the potential of predicting the mean block volume of multiple-set jointed rock masses with an acceptable accuracy for common uses in most practical rock engineering applications.

Finite-difference time-domain (FDTD) analysis on the interaction between a metal block and a radially polarized focused beam.

PubMed

Kitamura, Kyoko; Sakai, Kyosuke; Noda, Susumu

2011-07-18

Radially polarized focused beams have attracted a great deal of attention because of their unique properties characterized by the longitudinal field. Although this longitudinal field is strongly confined to the beam axis, the energy flow, i.e., the Poynting vector, has null intensity on the axis. Hence, the interaction of the focused beam and matter has thus far been unclear. We analyzed the interactions between the focused beam and a subwavelength metal block placed at the center of the focus using three-dimensional finite-difference time-domain (FDTD) calculation. We found that most of the Poynting energy propagates through to the far-field, and that a strong enhancement of the electric field appeared on the metal surface. This enhancement is attributed to the constructive interference of the symmetric electric field and the coupling to the surface plasmon mode.

Optimal domain decomposition strategies

NASA Technical Reports Server (NTRS)

Yoon, Yonghyun; Soni, Bharat K.

1995-01-01

The primary interest of the authors is in the area of grid generation, in particular, optimal domain decomposition about realistic configurations. A grid generation procedure with optimal blocking strategies has been developed to generate multi-block grids for a circular-to-rectangular transition duct. The focus of this study is the domain decomposition which optimizes solution algorithm/block compatibility based on geometrical complexities as well as the physical characteristics of flow field. The progress realized in this study is summarized in this paper.

Present-day velocity field and block kinematics of Tibetan Plateau from GPS measurements

NASA Astrophysics Data System (ADS)

Wang, Wei; Qiao, Xuejun; Yang, Shaomin; Wang, Dijin

2017-02-01

In this study, we present a new synthesis of GPS velocities for tectonic deformation within the Tibetan Plateau and its surrounding areas, a combined data set of ˜1854 GPS-derived horizontal velocity vectors. Assuming that crustal deformation is localized along major faults, a block modelling approach is employed to interpret the GPS velocity field. We construct a 30-element block model to describe present-day deformation in western China, with half of them located within the Tibetan Plateau, and the remainder located in its surrounding areas. We model the GPS velocities simultaneously for the effects of block rotations and elastic strain induced by the bounding faults. Our model yields a good fit to the GPS data with a mean residual of 1.08 mm a-1 compared to the mean uncertainty of 1.36 mm a-1 for each velocity component, indicating a good agreement between the predicted and observed velocities. The major strike-slip faults such as the Altyn Tagh, Xianshuihe, Kunlun and Haiyuan faults have relatively uniform slip rates in a range of 5-12 mm a-1 along most of their segments, and the estimated fault slip rates agree well with previous geologic and geodetic results. Blocks having significant residuals are located at the southern and southeastern Tibetan Plateau, suggesting complex tectonic settings and further refinement of accurate definition of block geometry in these regions.

Preliminary design of two Space Shuttle fluid physics experiments

NASA Technical Reports Server (NTRS)

Gat, N.; Kropp, J. L.

1984-01-01

The mid-deck lockers of the STS and the requirements for operating an experiment in this region are described. The design of the surface tension induced convection and the free surface phenomenon experiments use a two locker volume with an experiment unique structure as a housing. A manual mode is developed for the Surface Tension Induced Convection experiment. The fluid is maintained in an accumulator pre-flight. To begin the experiment, a pressurized gas drives the fluid into the experiment container. The fluid is an inert silicone oil and the container material is selected to be comparable. A wound wire heater, located axisymmetrically above the fluid can deliver three wattages to a spot on the fluid surface. These wattages vary from 1-15 watts. Fluid flow is observed through the motion of particles in the fluid. A 5 mw He/Ne laser illuminates the container. Scattered light is recorded by a 35mm camera. The free surface phenomena experiment consists of a trapezoidal cell which is filled from the bottom. The fluid is photographed at high speed using a 35mm camera which incorporated the entire cell length in the field of view. The assembly can incorporate four cells in one flight. For each experiment, an electronics block diagram is provided. A control panel concept is given for the surface induced convection. Both experiments are within the mid-deck locker weight and c-g limits.

Opportunities for increasing natural gas production in the near term. Volume VI. The East Cameron Block 271 Field. Final report

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

Not Available

1978-02-01

This report examines the potential for increasing the rate of production of natural gas from the East Cameron Block 271 Field in the Gulf of Mexico Outer Continental Shelf. Proved reserves are estimated using all available reservoir data, including well logs and pressure tests, and cost parameters typical in the area. Alternative schedules for future production are devised, and net present values calculated from which the maximum production rate that also maximizes net present value is determined.

Thermohydrologic modeling of the large-block test in partially saturated fractured tuff at Yucca Mountain, Nevada

NASA Astrophysics Data System (ADS)

Lee, K.; Buscheck, T. A.; Glascoe, L. G.; Gansemer, J.; Sun, Y.

2002-12-01

In support of the characterization of Yucca Mountain as a potential site for as a geologic repository for high-level nuclear waste, the US Department of Energy conducted the Large Block Test (LBT) at nearby Fran Ridge. The LBT was conducted in an excavated 3x 3x 4.5m block of partially saturated, fractured nonlithophysal Topopah Spring tuff, which is one of the host-rock units for the potential repository at Yucca Mountain. The LBT was one of a series of field-scale thermohydrologic tests conducted in the repository host-rock units. The LBT was heated by line heaters installed in five boreholes lying in a horizontal plane 2.75 m below the upper surface of the block. The field-scale thermal tests were designed to help investigators better understand the coupled thermohydrologic-mechanical-chemical processes that would occur in the host rock in response to the radioactive heat of decay from emplaced waste packages. The tests also provide data for the calibration and validation of numerical models used to analyze the thermohydrologic response of the near-field host rock and Engineered Barrier System (EBS). Using the NUFT code and the dual-permeability approach to representing fracture-matrix interaction, we simulated the thermohydrologic response of the block to a heating and cooling cycle. The primary goals of the analysis were to study the heat-flow mechanisms and water redistribution patterns in the boiling and sub-boiling zones, and to compare model results with measured temperature and liquid saturation data, and thereby evaluate two rock property data sets available for modeling thermohydrologic behavior in the rock. Model results were also used for model calibration and validation. We obtained a good to excellent match between model and observed temperatures, and found that the distinct dryout and condensation zones modeled above and below the heater level agreed fairly well with the liquid-saturation measurements. We identified the best-fit data set by using a statistical analysis to compare model and field temperatures, and found that heat flow in the block was dominated by conduction.

Application of augmented reality for inferior alveolar nerve block anesthesia: A technical note

PubMed Central

2017-01-01

Efforts to apply augmented reality (AR) technology in the medical field include the introduction of AR techniques into dental practice. The present report introduces a simple method of applying AR during an inferior alveolar nerve block, a procedure commonly performed in dental clinics. PMID:28879340

Application of augmented reality for inferior alveolar nerve block anesthesia: A technical note.

PubMed

Won, Yu-Jin; Kang, Sang-Hoon

2017-06-01

Efforts to apply augmented reality (AR) technology in the medical field include the introduction of AR techniques into dental practice. The present report introduces a simple method of applying AR during an inferior alveolar nerve block, a procedure commonly performed in dental clinics.

Precomplexation and Activation of Carboxylate and Phosphate Esters

DTIC Science & Technology

1992-03-02

SUBJECT TERMS (Continue on reverse if necessary and identify by block number) FIELD GROUP SUB-GROUP 07 03 19 ABSTRACT (Continue on reverse if...necessary and identify by block number) This is the final report for contract N00014-88-K-0309. It summarizes our previously submitted Technical Reports #1

Inclusion Complexes of Diisopropyl Fluorophosphate with Cyclodextrins.

DTIC Science & Technology

1987-09-01

SUPPLEMENTARY NOTATION For Submission to Journal of Catalysis. 17. COSATI CODES 18. SUBJECT TERMS (Continue on reverse if necessary and identify by block...number) FIELD GROUP SUB-GROUP 19. ABSTRACT (Continue on reverse if necessary and identify by block number) See Attached DTIC S ELECTESNOV 2 3 1987D 20

Instructional Guide for Air Conditioning and Refrigeration. V & TECC Curriculum Guide.

ERIC Educational Resources Information Center

Duenk, Lester G.; And Others

This trade and industrial curriculum guide is intended for use in vocational programs that prepare students to enter the air conditioning/refrigeration field. The introductory section provides a statement of philosophy, objectives, block time schedule, and recommended facilities and equipment. Following the introductory section, eighteen blocks of…

Evidence of formation of site-selective inclusion complexation between beta-cyclodextrin and poly(ethylene oxide)-block-poly(propylene oxide)- block-poly(ethylene oxide) copolymers.

PubMed

Tsai, Chi-Chun; Zhang, Wen-Bin; Wang, Chien-Lung; Van Horn, Ryan M; Graham, Matthew J; Huang, Jing; Chen, Yongming; Guo, Mingming; Cheng, Stephen Z D

2010-05-28

A series of inclusion complexes of poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (PEO-b-PPO-b-PEO) with beta-cyclodextrin (beta-CD) was prepared. Their formation, structure, and dynamics were investigated by solution two-dimensional rotating-frame Overhauser effect spectroscopy (2D ROESY) and one-dimensional (1D) and 2D solid-state (13)C NMR. The inclusion complexes between the PEO-b-PPO-b-PEO copolymers and the beta-CDs were formed in aqueous solution and detected by 2D ROESY. The high efficiency of cross polarization and spin diffusion experiments in (13)C solid-state NMR showed that the mobility of the PPO blocks dramatically decreases after beta-CD complexation, indicating that they are selectively incorporated onto the PPO blocks. The hydrophobic cavities of beta-CD restrict the PPO block mobility, which is evidence of the formation of inclusion complexes in the solid state. The 2D wide-line separation NMR experiments suggested that beta-CDs only thread onto the PPO blocks while forming the inclusion complexes. The stoichiometry of inclusion complexes was studied using (1)H NMR, and a 3:1 (PO unit to beta-CD) was found for all inclusion complexes, which indicated that the number of threaded beta-CDs was only dependent on the molecular weight of the PPO blocks. 1D wide angle x-ray diffraction studies demonstrated that the beta-CD in the inclusion complex formed a channel-like structure that is different from the pure beta-CD crystal structure.

Evidence of formation of site-selective inclusion complexation between β-cyclodextrin and poly(ethylene oxide)-block-poly(propylene oxide)- block-poly(ethylene oxide) copolymers

NASA Astrophysics Data System (ADS)

Tsai, Chi-Chun; Zhang, Wen-Bin; Wang, Chien-Lung; Van Horn, Ryan M.; Graham, Matthew J.; Huang, Jing; Chen, Yongming; Guo, Mingming; Cheng, Stephen Z. D.

2010-05-01

A series of inclusion complexes of poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (PEO-b-PPO-b-PEO) with β-cyclodextrin (β-CD) was prepared. Their formation, structure, and dynamics were investigated by solution two-dimensional rotating-frame Overhauser effect spectroscopy (2D ROESY) and one-dimensional (1D) and 2D solid-state C13 NMR. The inclusion complexes between the PEO-b-PPO-b-PEO copolymers and the β-CDs were formed in aqueous solution and detected by 2D ROESY. The high efficiency of cross polarization and spin diffusion experiments in C13 solid-state NMR showed that the mobility of the PPO blocks dramatically decreases after β-CD complexation, indicating that they are selectively incorporated onto the PPO blocks. The hydrophobic cavities of β-CD restrict the PPO block mobility, which is evidence of the formation of inclusion complexes in the solid state. The 2D wide-line separation NMR experiments suggested that β-CDs only thread onto the PPO blocks while forming the inclusion complexes. The stoichiometry of inclusion complexes was studied using H1 NMR, and a 3:1 (PO unit to β-CD) was found for all inclusion complexes, which indicated that the number of threaded β-CDs was only dependent on the molecular weight of the PPO blocks. 1D wide angle x-ray diffraction studies demonstrated that the β-CD in the inclusion complex formed a channel-like structure that is different from the pure β-CD crystal structure.

Additivity pretraining and cue competition effects: developmental evidence for a reasoning-based account of causal learning.

PubMed

Simms, Victoria; McCormack, Teresa; Beckers, Tom

2012-04-01

The effect of additivity pretraining on blocking has been taken as evidence for a reasoning account of human and animal causal learning. If inferential reasoning underpins this effect, then developmental differences in the magnitude of this effect in children would be expected. Experiment 1 examined cue competition effects in children's (4- to 5-year-olds and 6- to 7-year-olds) causal learning using a new paradigm analogous to the food allergy task used in studies of human adult causal learning. Blocking was stronger in the older than the younger children, and additivity pretraining only affected blocking in the older group. Unovershadowing was not affected by age or by pretraining. In experiment 2, levels of blocking were found to be correlated with the ability to answer questions that required children to reason about additivity. Our results support an inferential reasoning explanation of cue competition effects. (c) 2012 APA, all rights reserved.

Electronic and optoelectronic nano-devices based on carbon nanotubes.

PubMed

Scarselli, M; Castrucci, P; De Crescenzi, M

2012-08-08

The discovery and understanding of nanoscale phenomena and the assembly of nanostructures into different devices are among the most promising fields of material science research. In this scenario, carbon nanostructures have a special role since, in having only one chemical element, they allow physical properties to be calculated with high precision for comparison with experiment. Carbon nanostructures, and carbon nanotubes (CNTs) in particular, have such remarkable electronic and structural properties that they are used as active building blocks for a large variety of nanoscale devices. We review here the latest advances in research involving carbon nanotubes as active components in electronic and optoelectronic nano-devices. Opportunities for future research are also identified.

A Numerical Approach to the Accretion of Micro-Continental Blocks and Subsequent Subduction Initiation

NASA Astrophysics Data System (ADS)

Gün, E.; Gogus, O.; Pysklywec, R.; Topuz, G.; Bodur, O. F.

2017-12-01

The Tethyan belt in the eastern Mediterranean region is characterized by the accretion of several micro-continental blocks (e.g. Anatolide-Tauride, Sakarya and Istanbul terranes). The accretion of a micro-continental block to the active continental margin and subsequent initiation of a new subduction are of crucial importance in understanding the geodynamic evolution of the region. Numerical geodynamic experiments are designed to investigate how these micro-continental blocks in the ocean-continent subduction system develops the aforementioned subduction, back-arc extension, surface uplift and the ophiolite emplacement in the eastern Mediterranean since Late Cretaceous. In a series set of experiments, we test various sizes of micro-continental blocks (ranging from 50 to 300 km), different rheological properties (e.g. dry-wet olivine mantle) and imposed plate convergence velocities (0 to 4 cm/year). For a prime present-day analogue to the micro-continental block collision-accretion, model predictions are compared against the collision between Eratosthenes and Cyprus. Preliminary results show that slab break-off occurs directly after the collision when the plate convergence velocities are less than 2 cm/yr and the mantle lithosphere of the continental block has viscoplastic rheology. On the other hand, there is no relationship between convergence rate and break-off event when the lithospheric mantle rheology is chosen to be plastic. Furthermore, the micro-continental block undergoes considerable extension before continental collision due to the slab pull force, if a viscoplastic rheology is assumed for the mantle lithosphere.

Testing the Multispecimen Absolute Paleointensity Method with Archaeological Baked Clays and Bricks: New Data for Central Europe

NASA Astrophysics Data System (ADS)

Schnepp, Elisabeth; Leonhardt, Roman

2014-05-01

The domain-state corrected multiple-specimen paleointensity determination technique (MSP-DSC, Fabian & Leonhardt, EPSL 297, 84, 2010) has been tested for archaeological baked clays and bricks. The following procedure was applied: (1) Exclusion of secondary overprints using alternating field (AF) or thermal demagnetization and assignment of characteristic remanent magnetization (ChRM) direction. (2) Determination of magneto mineralogical alteration using anhysteretic remanent magnetization (ARM) or temperature dependence of susceptibility. (3) Measurement of ARM anisotropy tensor, calculation of the ancient magnetic field direction. (4) Sister specimens were subjected to the MSP-DSC technique aligned (anti-)parallel to the ancient magnetic field direction. (5) Several checks were applied in order to exclude data points from further evaluation: (a) The accuracy of orientation (< 10°), (b) absence of secondary components (< 10°), (c) use of a considerable NRM fraction (20 to 80%), (d) weak alteration (smaller than for domain state change) and finally (e) domain state correction was applied. Bricks and baked clays from archaeological sites with ages between 645 BC and 2003 AD have been subjected to MSP-DSC absolute paleointensity (PI) determination. Aims of study are to check precision and reliability of the method. The obtained PI values are compared with direct field observation, the IGRF, the GUFM1 or Thellier results. The Thellier experiments often show curved lines and pTRM checks fail for higher temperatures. Nevertheless in the low temperature range straight lines have been obtained but they provide scattered paleointensity values. Mean paleointensites have relative errors often exceeding 10%, which are not considered as high quality PI estimates. MSP-DSC experiments for the structures older than 300 years are still under progress. The paleointensities obtained from the MSP-DSC experiments for the young materials (after 1700 AD) have small relative errors of a few or even less than one per cent, although the data points are scattered in some cases. For these sites comparison with the historical field values shows very good agreement. Small deviations could be explained by the higher cooling rates used in the laboratory. These young structures were made of bricks and the unweathered baked clay of the 2003 experimental kiln was like brick, either. The sites provided much material so that tests were done to investigate the MSP-DSC methodology further. For example it was tested, if different NRM deblocking fractions have influence on the paleointensity estimate. It seems that use of fractions lower than 20% of the NRM can lead to an underestimation of PI. Although MSP-DSC experiments carried out on different blocks of the same structure can provide very similar results, the use of several fragments from at least five different units (potshards, bricks, in situ burnt blocks or rocks) of the same structure is recommended in or to obtain a reliable estimate of the experimental errors. Five data points may define already a well constraint straight line, but for a better precision 15 (< 2%) data points may be required. For the young structures the MSP-DSC method provided reliable PI estimates which have been included into the archaeointensity data base

Assessment of Neutron Contamination Originating from the Presence of Wedge and Block in Photon Beam Radiotherapy.

PubMed

Bahreyni Toossi, M T; Khajetash, B; Ghorbani, M

2018-03-01

One of the main causes of induction of secondary cancer in radiation therapy is neutron contamination received by patients during treatment. Objective: In the present study the impact of wedge and block on neutron contamination production is investigated. The evaluations are conducted for a 15 MV Siemens Primus linear accelerator. Simulations were performed using MCNPX Monte Carlo code. 30˚, 45˚ and 60˚ wedges and a cerrobend block with dimensions of 1.5 × 1.5 × 7 cm 3 were simulated. The investigation were performed in the 10 × 10 cm 2 field size at source to surface distance of 100 cm for depth of 0.5, 2, 3 and 4 cm in a water phantom. Neutron dose was calculated using F4 tally with flux to dose conversion factors and F6 tally. Results showed that the presence of wedge increases the neutron contamination when the wedge factor was considered. In addition, 45˚ wedge produced the most amount of neutron contamination. If the block is in the center of the field, the cerrobend block caused less neutron contamination than the open field due to absorption of neutrons and photon attenuation. The results showed that neutron contamination is less in steeper depths. The results for two tallies showed practically equivalent results. Wedge causes neutron contamination hence should be considered in therapeutic protocols in which wedge is used. In terms of clinical aspects, the results of this study show that superficial tissues such as skin will tolerate more neutron contamination than the deep tissues.

Meso-beta scale perturbations of the wind field by thunderstorm cells

NASA Technical Reports Server (NTRS)

Ulanski, S. L.; Heymsfield, G. M.

1986-01-01

Data from the high density storm-scale rawinsonde network of the Severe Environmental Storms and Mesoscale Experiment revealed temporal and spatial changes in the divergence fields of the troposphere in response to severe storm evolution on May 2, 1979; these changes were detectable on the meso-beta scale. This unique set of data was subsequently used to study the evolution of the wind, divergence and vertical motion fields in the presence of intense convection. Mid- and upper-tropospheric divergence was superimposed over low-level convergence. The divergence, which has a maximum value of .0004/s, occurred 75 to 100 km upwind as well as over the tornadic cells. To the south of the storm cells, the kinematic pattern was in reverse, upper level convergence was superimposed over low-level divergence. A vertical motion doublet was found to ascend over the squall line and descend about 70 km south of the squall line. It is suggested that the following effects are accountable for the nature of the kinematic fields: (1) blocking of tropospheric environmental flow by the storm cells, (2) anvil outflows, particularly from the tornadic cells, and (3) divergence from the exit region of the jet stream.

Performance and Mechanisms of Ultrafiltration Membrane Fouling Mitigation by Coupling Coagulation and Applied Electric Field in a Novel Electrocoagulation Membrane Reactor.

PubMed

Sun, Jingqiu; Hu, Chengzhi; Tong, Tiezheng; Zhao, Kai; Qu, Jiuhui; Liu, Huijuan; Elimelech, Menachem

2017-08-01

A novel electrocoagulation membrane reactor (ECMR) was developed, in which ultrafiltration (UF) membrane modules are placed between electrodes to improve effluent water quality and reduce membrane fouling. Experiments with feedwater containing clays (kaolinite) and natural organic matter (humic acid) revealed that the combined effect of coagulation and electric field mitigated membrane fouling in the ECMR, resulting in higher water flux than the conventional combination of electrocoagulation and UF in separate units (EC-UF). Higher current densities and weakly acidic pH in the EMCR favored faster generation of large flocs and effectively reduced membrane pore blocking. The hydraulic resistance of the formed cake layers on the membrane surface in ECMR was reduced due to an increase in cake layer porosity and polarity, induced by both coagulation and the applied electric field. The formation of a polarized cake layer was controlled by the applied current density and voltage, with cake layers formed under higher electric field strengths showing higher porosity and hydrophilicity. Compared to EC-UF, ECMR has a smaller footprint and could achieve significant energy savings due to improved fouling resistance and a more compact reactor design.

Wavelength-scale photonic-crystal laser formed by electron-beam-induced nano-block deposition.

PubMed

Seo, Min-Kyo; Kang, Ju-Hyung; Kim, Myung-Ki; Ahn, Byeong-Hyeon; Kim, Ju-Young; Jeong, Kwang-Yong; Park, Hong-Gyu; Lee, Yong-Hee

2009-04-13

A wavelength-scale cavity is generated by printing a carbonaceous nano-block on a photonic-crystal waveguide. The nanometer-size carbonaceous block is grown at a pre-determined region by the electron-beam-induced deposition method. The wavelength-scale photonic-crystal cavity operates as a single mode laser, near 1550 nm with threshold of approximately 100 microW at room temperature. Finite-difference time-domain computations show that a high-quality-factor cavity mode is defined around the nano-block with resonant wavelength slightly longer than the dispersion-edge of the photonic-crystal waveguide. Measured near-field images exhibit photon distribution well-localized in the proximity of the printed nano-block. Linearly-polarized emission along the vertical direction is also observed.

Sediment trapping efficiency of adjustable check dam in laboratory and field experiment

NASA Astrophysics Data System (ADS)

Wang, Chiang; Chen, Su-Chin; Lu, Sheng-Jui

2014-05-01

Check dam has been constructed at mountain area to block debris flow, but has been filled after several events and lose its function of trapping. For the reason, the main facilities of our research is the adjustable steel slit check dam, which with the advantages of fast building, easy to remove or adjust it function. When we can remove transverse beams to drain sediments off and keep the channel continuity. We constructed adjustable steel slit check dam on the Landow torrent, Huisun Experiment Forest station as the prototype to compare with model in laboratory. In laboratory experiments, the Froude number similarity was used to design the dam model. The main comparisons focused on types of sediment trapping and removing, sediment discharge, and trapping rate of slit check dam. In different types of removing transverse beam showed different kind of sediment removal and differences on rate of sediment removing, removing rate, and particle size distribution. The sediment discharge in check dam with beams is about 40%~80% of check dam without beams. Furthermore, the spacing of beams is considerable factor to the sediment discharge. In field experiment, this research uses time-lapse photography to record the adjustable steel slit check dam on the Landow torrent. The typhoon Soulik made rainfall amounts of 600 mm in eight hours and induced debris flow in Landow torrent. Image data of time-lapse photography demonstrated that after several sediment transport event the adjustable steel slit check dam was buried by debris flow. The result of lab and field experiments: (1)Adjustable check dam could trap boulders and stop woody debris flow and flush out fine sediment to supply the need of downstream river. (2)The efficiency of sediment trapping in adjustable check dam with transverse beams was significantly improved. (3)The check dam without transverse beams can remove the sediment and keep the ecosystem continuity.

The rapid cooling of the Nansha Block, southern South China Sea

NASA Astrophysics Data System (ADS)

Dong, M.; Zhang, J.

2017-12-01

Since the Late Cretaceous and Cenozoic, the Nansha Block has experienced a series of tectonic process and separated from South China continent to the south. As an exotic micro-continental, Nansha Block has an obvious different lithospheric rheology property from surrounding region. The lithosphere and mantle dynamic and rheology are mainly controlled by temperature. Therefore, we calculated the 3D temperature field and geothermal gradient of Nansha Block's upper mantle by using the S-wave velocity structure from surface wave tomography. The results show that the depth where temperature of 1300° as the lithospheric thickness is in close correspondence with the top of the seismic low velocity zone. The temperature of the upper mantle in Nansha Block is significantly lower than that of surrounding. It implies that Nansha Block experienced a rapid cooling event. We propose that the rapid cooling can be partly attributed to three reasons: 1) Nansha Block is a relatively stable block with no interior geothermal activity. 2) No external heat source to provide energy. 3) Abnormal mantle convection under Nansha Block accelerated the cooling.

High-voltage lateral double-implanted MOSFETs implemented on high-purity semi-insulating 4H-SiC substrates with gate field plates

NASA Astrophysics Data System (ADS)

Seok, Ogyun; Kim, Hyoung Woo; Moon, Jeong Hyun; Lee, Hyun-Su; Bahng, Wook

2018-06-01

Lateral double-implanted MOSFETs (LDIMOSFETs) fabricated on on-axis high-purity semi-insulating (HPSI) 4H-SiC substrates with gate field plates have been demonstrated for the enhancement of reverse blocking capability. The effects of gate field plate on LDIMOSFET were analyzed by simulation and experimental methods. The electric field concentration at the gate edge was successfully suppressed by a gate field plate. A high breakdown voltage of 934 V and a figure of merit of 14.6 MW/cm2 were achieved at L FP of 2 µm and L drift of 15 µm, while those of the conventional device without a gate field plate were 744 V and 13.3 MW/cm2, respectively. Also, the fabricated device shows stable blocking characteristics at a high temperature of 250 °C. The drain leakage was increased by only 22% at 250 °C compared with that at room temperature.

Initial colonization, erosion and accretion of coral substrate

NASA Astrophysics Data System (ADS)

Davies, Peter J.; Hutchings, Patricia A.

1983-08-01

Blocks cut from Porites lutea were laid on the fore reef slope, reef flat and a lagoonal patch reef at Lizard Island, in the Northern Great Barrier Reef, and replicates removed from each environment at intervals of three months over a period of one and a half years. Variations in bioeroders and bioaccretors were noted. Microfaunas are far more numerous than macrofaunas as block colonizers; the principal borers are polychaete worms, whereas encrusters are molluscs, bryozoans, serpulids and solitary corals. The reef slope is more readily colonised by microfauna pioneer communities than are the other areas. All the environments exhibit a change from cirratulids to either sabellids or spionids (polydorids) over the length of the experiment. Accretion occurred on all blocks during the experiment, with significant differences detectable between environments; both reef slope and reef flat blocks showed weight increases of 9 10% whereas blocks from the patch reef showed increases of 15%. Annual erosion rates produced by polychaete worms are 0.694 kg m-2 year-1 (reef front), 0.843 kg m-2 year-1 (reef flat) and 1.788 kg m-2 year-1 (patch reef).

Periodically microstructured composite films made by electric- and magnetic-directed colloidal assembly

PubMed Central

Demirörs, Ahmet Faik; Courty, Diana; Libanori, Rafael; Studart, André R.

2016-01-01

Living organisms often combine soft and hard anisotropic building blocks to fabricate composite materials with complex microstructures and outstanding mechanical properties. An optimum design and assembly of the anisotropic components reinforces the material in specific directions and sites to best accommodate multidirectional external loads. Here, we fabricate composite films with periodic modulation of the soft–hard microstructure by simultaneously using electric and magnetic fields. We exploit forefront directed-assembly approaches to realize highly demanded material microstructural designs and showcase a unique example of how one can bridge colloidal sciences and composite technology to fabricate next-generation advanced structural materials. In the proof-of-concept experiments, electric fields are used to dictate the position of the anisotropic particles through dielectrophoresis, whereas a rotating magnetic field is used to control the orientation of the particles. By using such unprecedented control over the colloidal assembly process, we managed to fabricate ordered composite microstructures with up to 2.3-fold enhancement in wear resistance and unusual site-specific hardness that can be locally modulated by a factor of up to 2.5. PMID:27071113

APPARATUS FOR PRODUCING IONS OF VAPORIZABLE MATERIALS

DOEpatents

Wright, B.T.

1958-01-28

a uniform and copious supply of ions. The source comprises a hollow arc- block and means for establishing a magnetic field through the arc-block. Vaporization of the material to be ionized is produced by an electric heated filament. The arc producing structure within the arc-block consists of a cathode disposed between a pair of collimating electrodes along with an anode adjacent each collimating electrode on the side opposite the cathode. A positive potential applied to the anodes and collimating electrodes, with respect to the cathode, and the magnetic field act to accelerate the electrons from the cathode through a slit in each collimating clectrode towards the respective anode. In this manner a pair of collinear arc discharges are produced in the gas region which can be tapped for an abundant supply of ions of the material being analyzed.

The formation and analysis of a 5 deg equal area block terrestrial gravity field

NASA Technical Reports Server (NTRS)

Rapp, R. H.

1972-01-01

A set of 23,355 1 degree x 1 degree mean free air anomalies were used to predict a set of 5 degree equal area anomalies and their standard errors. Using the 1 degree data incorporating geophysically predicted values of ACIC, 1283 5 degree blocks were computed. Excluding the geophysically predicted anomalies 1249 blocks were computed. The 1 degree data were also used to compute covariance functions and the equatorial gravity and flattening implied by this data. The predicted anomalies were supplemented by model anomalies to form a complete 1654 global anomaly field. These data were used in a weighted least squares to determine potential coefficients to degree 15, and in a summation type formulation to determine potential coefficients to degree 25. These potential coefficients sets are compared to recent satellite determinations.

Pickering emulsions stabilized by biodegradable block copolymer micelles for controlled topical drug delivery.

PubMed

Laredj-Bourezg, Faiza; Bolzinger, Marie-Alexandrine; Pelletier, Jocelyne; Chevalier, Yves

2017-10-05

Surfactant-free biocompatible and biodegradable Pickering emulsions were investigated as vehicles for skin delivery of hydrophobic drugs. O/w emulsions of medium-chain triglyceride (MCT) oil droplets loaded with all-trans retinol as a model hydrophobic drug were stabilized by block copolymer nanoparticles: either poly(lactide)-block-poly(ethylene glycol) (PLA-b-PEG) or poly(caprolactone)-block-poly(ethylene glycol) (PCL-b-PEG). Those innovative emulsions were prepared using two different processes allowing drug loading either inside oil droplets or inside both oil droplets and non-adsorbed block copolymer nanoparticles. Skin absorption of retinol was investigated in vitro on pig skin biopsies using the Franz cell method. Supplementary experiments by confocal fluorescence microscopy allowed the visualization of skin absorption of the Nile Red dye on histological sections. Retinol and Nile Red absorption experiments showed the large accumulation of hydrophobic drugs in the stratum corneum for the Pickering emulsions compared to the surfactant-based emulsion and an oil solution. Loading drug inside both oil droplets and block copolymer nanoparticles enhanced again skin absorption of drugs, which was ascribed to the supplementary contribution of free block copolymer nanoparticles loaded with drug. Such effect allowed tuning drug delivery to skin over a wide range by means of a suitable selection of either the formulation or the drug loading process. Copyright © 2017 Elsevier B.V. All rights reserved.

Text extraction method for historical Tibetan document images based on block projections

NASA Astrophysics Data System (ADS)

Duan, Li-juan; Zhang, Xi-qun; Ma, Long-long; Wu, Jian

2017-11-01

Text extraction is an important initial step in digitizing the historical documents. In this paper, we present a text extraction method for historical Tibetan document images based on block projections. The task of text extraction is considered as text area detection and location problem. The images are divided equally into blocks and the blocks are filtered by the information of the categories of connected components and corner point density. By analyzing the filtered blocks' projections, the approximate text areas can be located, and the text regions are extracted. Experiments on the dataset of historical Tibetan documents demonstrate the effectiveness of the proposed method.

Weighted bi-prediction for light field image coding

NASA Astrophysics Data System (ADS)

Conti, Caroline; Nunes, Paulo; Ducla Soares, Luís.

2017-09-01

Light field imaging based on a single-tier camera equipped with a microlens array - also known as integral, holoscopic, and plenoptic imaging - has currently risen up as a practical and prospective approach for future visual applications and services. However, successfully deploying actual light field imaging applications and services will require developing adequate coding solutions to efficiently handle the massive amount of data involved in these systems. In this context, self-similarity compensated prediction is a non-local spatial prediction scheme based on block matching that has been shown to achieve high efficiency for light field image coding based on the High Efficiency Video Coding (HEVC) standard. As previously shown by the authors, this is possible by simply averaging two predictor blocks that are jointly estimated from a causal search window in the current frame itself, referred to as self-similarity bi-prediction. However, theoretical analyses for motion compensated bi-prediction have suggested that it is still possible to achieve further rate-distortion performance improvements by adaptively estimating the weighting coefficients of the two predictor blocks. Therefore, this paper presents a comprehensive study of the rate-distortion performance for HEVC-based light field image coding when using different sets of weighting coefficients for self-similarity bi-prediction. Experimental results demonstrate that it is possible to extend the previous theoretical conclusions to light field image coding and show that the proposed adaptive weighting coefficient selection leads to up to 5 % of bit savings compared to the previous self-similarity bi-prediction scheme.

Euclidean scalar field theory in the bilocal approximation

NASA Astrophysics Data System (ADS)

Nagy, S.; Polonyi, J.; Steib, I.

2018-04-01

The blocking step of the renormalization group method is usually carried out by restricting it to fluctuations and to local blocked action. The tree-level, bilocal saddle point contribution to the blocking, defined by the infinitesimal decrease of the sharp cutoff in momentum space, is followed within the three dimensional Euclidean ϕ6 model in this work. The phase structure is changed, new phases and relevant operators are found, and certain universality classes are restricted by the bilocal saddle point.

Revised estimation of 550-km times 550-km mean gravity anomalies

NASA Technical Reports Server (NTRS)

Williamson, M. R.

1977-01-01

The calculation of 550-km x 550-km mean gravity anomalies from 1 degree x 1 degree mean free-air gravimetry data is discussed. The block estimate procedure developed by Kaula is used to obtain 1,504 of the 1,654 possible mean block anomalies. The estimated block anomalies calculated from 1 deg x 1 deg mean anomalies referred to the reference ellipsoid and from 1 degree x 1 degree mean anomalies referred to a 24th-degree-and-order field are compared.

Deceleration of probe beam by stage bias potential improves resolution of serial block-face scanning electron microscopic images.

PubMed

Bouwer, James C; Deerinck, Thomas J; Bushong, Eric; Astakhov, Vadim; Ramachandra, Ranjan; Peltier, Steven T; Ellisman, Mark H

2017-01-01

Serial block-face scanning electron microscopy (SBEM) is quickly becoming an important imaging tool to explore three-dimensional biological structure across spatial scales. At probe-beam-electron energies of 2.0 keV or lower, the axial resolution should improve, because there is less primary electron penetration into the block face. More specifically, at these lower energies, the interaction volume is much smaller, and therefore, surface detail is more highly resolved. However, the backscattered electron yield for metal contrast agents and the backscattered electron detector sensitivity are both sub-optimal at these lower energies, thus negating the gain in axial resolution. We found that the application of a negative voltage (reversal potential) applied to a modified SBEM stage creates a tunable electric field at the sample. This field can be used to decrease the probe-beam-landing energy and, at the same time, alter the trajectory of the signal to increase the signal collected by the detector. With decelerated low landing-energy electrons, we observed that the probe-beam-electron-penetration depth was reduced to less than 30 nm in epoxy-embedded biological specimens. Concurrently, a large increase in recorded signal occurred due to the re-acceleration of BSEs in the bias field towards the objective pole piece where the detector is located. By tuning the bias field, we were able to manipulate the trajectories of the  primary and secondary electrons, enabling the spatial discrimination of these signals using an advanced ring-type BSE detector configuration or a standard monolithic BSE detector coupled with a blocking aperture.

Convolutional neural network for road extraction

NASA Astrophysics Data System (ADS)

Li, Junping; Ding, Yazhou; Feng, Fajie; Xiong, Baoyu; Cui, Weihong

2017-11-01

In this paper, the convolution neural network with large block input and small block output was used to extract road. To reflect the complex road characteristics in the study area, a deep convolution neural network VGG19 was conducted for road extraction. Based on the analysis of the characteristics of different sizes of input block, output block and the extraction effect, the votes of deep convolutional neural networks was used as the final road prediction. The study image was from GF-2 panchromatic and multi-spectral fusion in Yinchuan. The precision of road extraction was 91%. The experiments showed that model averaging can improve the accuracy to some extent. At the same time, this paper gave some advice about the choice of input block size and output block size.

Variation block-based genomics method for crop plants.

PubMed

Kim, Yul Ho; Park, Hyang Mi; Hwang, Tae-Young; Lee, Seuk Ki; Choi, Man Soo; Jho, Sungwoong; Hwang, Seungwoo; Kim, Hak-Min; Lee, Dongwoo; Kim, Byoung-Chul; Hong, Chang Pyo; Cho, Yun Sung; Kim, Hyunmin; Jeong, Kwang Ho; Seo, Min Jung; Yun, Hong Tai; Kim, Sun Lim; Kwon, Young-Up; Kim, Wook Han; Chun, Hye Kyung; Lim, Sang Jong; Shin, Young-Ah; Choi, Ik-Young; Kim, Young Sun; Yoon, Ho-Sung; Lee, Suk-Ha; Lee, Sunghoon

2014-06-15

In contrast with wild species, cultivated crop genomes consist of reshuffled recombination blocks, which occurred by crossing and selection processes. Accordingly, recombination block-based genomics analysis can be an effective approach for the screening of target loci for agricultural traits. We propose the variation block method, which is a three-step process for recombination block detection and comparison. The first step is to detect variations by comparing the short-read DNA sequences of the cultivar to the reference genome of the target crop. Next, sequence blocks with variation patterns are examined and defined. The boundaries between the variation-containing sequence blocks are regarded as recombination sites. All the assumed recombination sites in the cultivar set are used to split the genomes, and the resulting sequence regions are termed variation blocks. Finally, the genomes are compared using the variation blocks. The variation block method identified recurring recombination blocks accurately and successfully represented block-level diversities in the publicly available genomes of 31 soybean and 23 rice accessions. The practicality of this approach was demonstrated by the identification of a putative locus determining soybean hilum color. We suggest that the variation block method is an efficient genomics method for the recombination block-level comparison of crop genomes. We expect that this method will facilitate the development of crop genomics by bringing genomics technologies to the field of crop breeding.

Using R in experimental design with BIBD: An application in health sciences

NASA Astrophysics Data System (ADS)

Oliveira, Teresa A.; Francisco, Carla; Oliveira, Amílcar; Ferreira, Agostinho

2016-06-01

Considering the implementation of an Experimental Design, in any field, the experimenter must pay particular attention and look for the best strategies in the following steps: planning the design selection, conduct the experiments, collect observed data, proceed to analysis and interpretation of results. The focus is on providing both - a deep understanding of the problem under research and a powerful experimental process at a reduced cost. Mainly thanks to the possibility of allowing to separate variation sources, the importance of Experimental Design in Health Sciences is strongly recommended since long time. Particular attention has been devoted to Block Designs and more precisely to Balanced Incomplete Block Designs - in this case the relevance states from the fact that these designs allow testing simultaneously a number of treatments bigger than the block size. Our example refers to a possible study of inter reliability of the Parkinson disease, taking into account the UPDRS (Unified Parkinson's disease rating scale) in order to test if there are significant differences between the specialists who evaluate the patients performances. Statistical studies on this disease were described for example in Richards et al (1994), where the authors investigate the inter-rater Reliability of the Unified Parkinson's Disease Rating Scale Motor Examination. We consider a simulation of a practical situation in which the patients were observed by different specialists and the UPDRS on assessing the impact of Parkinson's disease in patients was observed. Assigning treatments to the subjects following a particular BIBD(9,24,8,3,2) structure, we illustrate that BIB Designs can be used as a powerful tool to solve emerging problems in this area. Once a structure with repeated blocks allows to have some block contrasts with minimum variance, see Oliveira et al. (2006), the design with cardinality 12 was selected for the example. R software was used for computations.

The disinhibitory zone of the striate neuron receptive field and its sensitivity to cross-like figures.

PubMed

Lazareva, N A; Shevelev, I A; Novikova, R V; Tikhomirov, A S; Sharaev, G A; Tsutskiridze, D Yu

2002-01-01

Acute experiments on immobilized anesthetized cats were used to confirm the suggestion that the sensitivity of many neurons on the primary visual cortex to cross-shaped, angular, and Y-shaped figures may be determined by the presence within their receptive fields of disinhibitory zones, which block end-stopping inhibition. A total of 55 neurons (84 functions, i.e.. on and off responses) were used for studies of sensitivity to crosses, and responses to single bars of different lengths were compared before and after stimulation of an additional lateral zone of the field (the presumptive disinhibitory zone), which was located in terms of responses to crosses. Seventeen of the 55 cells in which increases in the length of a single bar decreased responses, i.e., which demonstrated end-stopping inhibition, showed significant increases in responses (by an average factor of 2.06 +/- 0.16) during simultaneous stimulation of the lateral zone of the receptive field, which we interpreted as a disinhibitory effect on end-stopping inhibition. These data provide the first direct evidence for the role of end-stopping inhibition and its blockade by the disinhibitory zone of the receptive field in determining the sensitivity of some neurons in the primary visual cortex of the cat to cross-shaped figures.

Conformal Nets II: Conformal Blocks

NASA Astrophysics Data System (ADS)

Bartels, Arthur; Douglas, Christopher L.; Henriques, André

2017-08-01

Conformal nets provide a mathematical formalism for conformal field theory. Associated to a conformal net with finite index, we give a construction of the `bundle of conformal blocks', a representation of the mapping class groupoid of closed topological surfaces into the category of finite-dimensional projective Hilbert spaces. We also construct infinite-dimensional spaces of conformal blocks for topological surfaces with smooth boundary. We prove that the conformal blocks satisfy a factorization formula for gluing surfaces along circles, and an analogous formula for gluing surfaces along intervals. We use this interval factorization property to give a new proof of the modularity of the category of representations of a conformal net.

Modulation of channel activity and gadolinium block of MscL by static magnetic fields.

PubMed

Petrov, Evgeny; Martinac, Boris

2007-02-01

The magnetic field of the Earth has for long been known to influence the behaviour and orientation of a variety of living organisms. Experimental studies of the magnetic sense have, however, been impaired by the lack of a plausible cellular and/or molecular mechanism providing meaningful explanation for detection of magnetic fields by these organisms. Recently, mechanosensitive (MS) ion channels have been implied to play a role in magnetoreception. In this study we have investigated the effect of static magnetic fields (SMFs) of moderate intensity on the activity and gadolinium block of MscL, the bacterial MS channel of large conductance, which has served as a model channel to study the basic physical principles of mechanosensory transduction in living cells. In addition to showing that direct application of the magnetic field decreased the activity of the MscL channel, our study demonstrates for the first time that SMFs can reverse the effect of gadolinium, a well-known blocker of MS channels. The results of our study are consistent with a notion that (1) the effects of SMFs on the MscL channels may result from changes in physical properties of the lipid bilayer due to diamagnetic anisotropy of phospholipid molecules and consequently (2) cooperative superdiamagnetism of phospholipid molecules under influence of SMFs could cause displacement of Gd(3+) ions from the membrane bilayer and thus remove the MscL channel block.

Bistable director alignments of nematic liquid crystals confined in frustrated substrates

NASA Astrophysics Data System (ADS)

Araki, Takeaki; Nagura, Jumpei

2017-01-01

We studied in-plane bistable alignments of nematic liquid crystals confined by two frustrated surfaces by means of Monte Carlo simulations of the Lebwohl-Lasher spin model. The surfaces are prepared with orientational checkerboard patterns, on which the director field is locally anchored to be planar yet orthogonal between the neighboring blocks. We found the director field in the bulk tends to be aligned along the diagonal axes of the checkerboard pattern, as reported experimentally [J.-H. Kim et al., Appl. Phys. Lett. 78, 3055 (2001), 10.1063/1.1371246]. The energy barrier between the two stable orientations is increased, when the system is brought to the isotropic-nematic transition temperature. Based on an elastic theory, we found that the bistability is attributed to the spatial modulation of the director field near the frustrated surfaces. As the block size is increased and/or the elastic modulus is reduced, the degree of the director inhomogeneity is increased, enlarging the energy barrier. We also found that the switching rate between the stable states is decreased when the block size is comparable to the cell thickness.

Behavior of P85 and P188 Poloxamer Molecules: Computer Simulations Using United Atom Force Field.

DOE PAGES

Goliaei, Ardeshir; Lau, Edmond Y.; Adhikari, Upendra; ...

2016-05-27

To study the interaction between poloxamer molecules and lipid bilayers using molecular dynamics simulation technique with the united atom resolution, we augmented the GROMOS force field to include poloxamers. We validated the force field by calculating the radii of gyration of two poloxamers, P85 and P188, solvated in water and by considering the poloxamer density distributions at the air/water interface. The emphasis of our simulations was on the study of the interaction between poloxamers and lipid bilayer. At the water/lipid bilayer interface, we observed that both poloxamers studied, P85 and P188, behaved like surfactants: the hydrophilic blocks of poloxamers becamemore » adsorbed at the polar interface, while their hydrophobic block penetrated the interface into the aliphatic tail region of the lipid bilayer. We also observed that when P85 and P188 poloxamers interacted with damaged membranes that contained pores, the hydrophobic blocks of copolymers penetrated into the membrane in the vicinity of the pore and compressed the membrane. Lastly, due to this compression, water molecules were evacuated from the pore.« less

Performance of low-rank QR approximation of the finite element Biot-Savart law

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

White, D; Fasenfest, B

2006-10-16

In this paper we present a low-rank QR method for evaluating the discrete Biot-Savart law. Our goal is to develop an algorithm that is easily implemented on parallel computers. It is assumed that the known current density and the unknown magnetic field are both expressed in a finite element expansion, and we wish to compute the degrees-of-freedom (DOF) in the basis function expansion of the magnetic field. The matrix that maps the current DOF to the field DOF is full, but if the spatial domain is properly partitioned the matrix can be written as a block matrix, with blocks representingmore » distant interactions being low rank and having a compressed QR representation. While an octree partitioning of the matrix may be ideal, for ease of parallel implementation we employ a partitioning based on number of processors. The rank of each block (i.e. the compression) is determined by the specific geometry and is computed dynamically. In this paper we provide the algorithmic details and present computational results for large-scale computations.« less

Blocking Spatial Navigation Across Environments That Have a Different Shape

PubMed Central

2015-01-01

According to the geometric module hypothesis, organisms encode a global representation of the space in which they navigate, and this representation is not prone to interference from other cues. A number of studies, however, have shown that both human and non-human animals can navigate on the basis of local geometric cues provided by the shape of an environment. According to the model of spatial learning proposed by Miller and Shettleworth (2007, 2008), geometric cues compete for associative strength in the same manner as non-geometric cues do. The experiments reported here were designed to test if humans learn about local geometric cues in a manner consistent with the Miller-Shettleworth model. Experiment 1 replicated previous findings that humans transfer navigational behavior, based on local geometric cues, from a rectangle-shaped environment to a kite-shaped environment, and vice versa. In Experiments 2 and 3, it was observed that learning about non-geometric cues blocked, and were blocked by, learning about local geometric cues. The reciprocal blocking observed is consistent with associative theories of spatial learning; however, it is difficult to explain the observed effects with theories of global-shape encoding in their current form. PMID:26569017

Description of CBETA magnet tuning wire holders

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

Brooks, S.

2017-07-19

A non-­magnetic insert will be placed directly inside the permanent magnet blocks in every CBETA Halbach magnet in order to hold a set of iron “tuning wires”. These wires have various lengths around the perimeter of the aperture in order to cancel multipole field errors from the permanent magnet blocks.

Tabletop Tectonics: Diverse Mountain Ranges Using Flour and Graphite

NASA Astrophysics Data System (ADS)

Davis, D. M.

2006-12-01

It has been recognized for some time that the frontal deformation zones where plates converge (foreland fold- and-thrust belts on continents and accretionary wedges at subduction zones) involve shortening over a decoupling layer, or decollement. A simple but successful way of explaining many aspects of their behavior is called the critical Coulomb wedge model, which regards these contractional wedges as analogous to the wedge-shaped mass of soil accreted in front of a bulldozer, or the wedge of snow that piles up in front of a snow plow. The shape and deformation history of the accreted wedge of soil or snow will depend upon the frictional strength of the material being plowed up and the surface over which it is being plowed. The same is true of `bulldozer' wedges consisting of many km thick piles of sediment at convergent plate margins. Using flour (or powdered milk), sandpaper, graphite, transparency sheets, and athletic field marker chalk, manipulated with sieves, brushes, pastry bags and blocks and sheets of wood, it is possible to demonstrate a wide variety of processes and tectonic styles observed at convergent plate boundaries. Model fold-and-thrust belts that behave like natural examples with a decollement that is strong (e.g., in rock without high pore fluid pressure) or weak (e.g., in a salt horizon or with elevated pore fluid pressure) can be generated simply by placing wither sandpaper or graphite beneath the flour that is pushed across the tabletop using a block of wood (the strong basement and hiterland rocks behind the fold-thrust belt). Depending upon the strength of the decollement, the cross-sectional taper of the deforming wedge will be thin or broad, the internal deformation mild or intense, and the structures either close to symmetric or strongly forward-vergent, just as at the analogous natural fold-thrust belts. Including a horizontal sheet of wood or Plexiglas in front of the pushing block allows generation of an accretionary wedge, outer-are high, and forearc basin, just as over a subduction zone. Any dark material emplaced (a pastry bag works well) atop the experiment before deformation in the form of football-field `hash marks' every 10 cm allows for easy calculation of strain distribution at any time during or after the experiment. Finally, the entire orogen can be excavated using a plastic photocopier transparency sheet. If the original set-up included occasional thin layers of red and blue field marker chalk within sedimentary column (the rest of which consists of white flour or powdered milk), excavation reveals (quite colorfully) many internal details of the fold-thrust belts that have been generated.

Fast Physically Correct Refocusing for Sparse Light Fields Using Block-Based Multi-Rate View Interpolation.

PubMed

Huang, Chao-Tsung; Wang, Yu-Wen; Huang, Li-Ren; Chin, Jui; Chen, Liang-Gee

2017-02-01

Digital refocusing has a tradeoff between complexity and quality when using sparsely sampled light fields for low-storage applications. In this paper, we propose a fast physically correct refocusing algorithm to address this issue in a twofold way. First, view interpolation is adopted to provide photorealistic quality at infocus-defocus hybrid boundaries. Regarding its conventional high complexity, we devised a fast line-scan method specifically for refocusing, and its 1D kernel can be 30× faster than the benchmark View Synthesis Reference Software (VSRS)-1D-Fast. Second, we propose a block-based multi-rate processing flow for accelerating purely infocused or defocused regions, and a further 3- 34× speedup can be achieved for high-resolution images. All candidate blocks of variable sizes can interpolate different numbers of rendered views and perform refocusing in different subsampled layers. To avoid visible aliasing and block artifacts, we determine these parameters and the simulated aperture filter through a localized filter response analysis using defocus blur statistics. The final quadtree block partitions are then optimized in terms of computation time. Extensive experimental results are provided to show superior refocusing quality and fast computation speed. In particular, the run time is comparable with the conventional single-image blurring, which causes serious boundary artifacts.

Symmetry breaking by bifundamentals

NASA Astrophysics Data System (ADS)

Schellekens, A. N.

2018-03-01

We derive all possible symmetry breaking patterns for all possible Higgs fields that can occur in intersecting brane models: bifundamentals and rank-2 tensors. This is a field-theoretic problem that was already partially solved in 1973 by Ling-Fong Li [1]. In that paper the solution was given for rank-2 tensors of orthogonal and unitary group, and U (N )×U (M ) and O (N )×O (M ) bifundamentals. We extend this first of all to symplectic groups. When formulated correctly, this turns out to be straightforward generalization of the previous results from real and complex numbers to quaternions. The extension to mixed bifundamentals is more challenging and interesting. The scalar potential has up to six real parameters. Its minima or saddle points are described by block-diagonal matrices built out of K blocks of size p ×q . Here p =q =1 for the solutions of Ling-Fong Li, and the number of possibilities for p ×q is equal to the number of real parameters in the potential, minus 1. The maximum block size is p ×q =2 ×4 . Different blocks cannot be combined, and the true minimum occurs for one choice of basic block, and for either K =1 or K maximal, depending on the parameter values.

Block copolymer systems: from single chain to self-assembled nanostructures.

PubMed

Giacomelli, Cristiano; Schmidt, Vanessa; Aissou, Karim; Borsali, Redouane

2010-10-19

Recent advances in the field of macromolecular engineering applied to the fabrication of nanostructured materials using block copolymer chains as elementary building blocks are described in this feature article. By highlighting some of our work in the area and accounting for the contribution of other groups, we discuss the relationship between the physical-chemical properties of copolymer chains and the characteristics of nano-objects originating from their self-assembly in solution and in bulk, with emphasis on convenient strategies that allow for the control of composition, functionality, and topology at different levels of sophistication. In the case of micellar nanoparticles in solution, in particular, we present approaches leading to morphology selection via macromolecular architectural design, the functionalization of external solvent-philic shells with biomolecules (polysaccharides and proteins), and the maximization of micelle loading capacity by the suitable choice of solvent-phobic polymer segments. The fabrication of nanomaterials mediated by thin block copolymer films is also discussed. In this case, we emphasize the development of novel polymer chain manipulation strategies that ultimately allow for the preparation of precisely positioned nanodomains with a reduced number of defects via block-selective chemical reactivity. The challenges facing the soft matter community, the urgent demand to convert huge public and private investments into consumer products, and future possible directions in the field are also considered herein.

Temperature behavior of the antiferromagnetic susceptibility of nanoferrihydrite from the measurements of the magnetization curves in fields of up to 250 kOe

NASA Astrophysics Data System (ADS)

Balaev, D. A.; Popkov, S. I.; Krasikov, A. A.; Balaev, A. D.; Dubrovskiy, A. A.; Stolyar, S. V.; Yaroslavtsev, R. N.; Ladygina, V. P.; Iskhakov, R. S.

2017-10-01

The cross-breeding problem of the temperature dependence of the antiferromagnetic susceptibility of ferrihydrite nanoparticles is considered. Iron ions Fe3+ in ferrihydrite are ordered antiferromagnetically; however, the existence of defects on the surface and in the bulk of nanoparticles induces a noncompensated magnetic moment that leads to a typical superparamagnetic behavior of ensemble of the nanoparticles with a characteristic blocking temperature. In an unblocked state, magnetization curves of such objects are described as a superposition of the Langevin function and the linear-in-field contribution of the antiferromagnetic "core" of the nanoparticles. According to many studies of the magnetization curves performed on ferrihydrite (and related ferritin) nanoparticles in fields to 60 kOe, dependence χAF( T) decreases as temperature increases, which was related before to the superantiferromagnetism effect. As the magnetic field range increases to 250 kOe, the values of χAF obtained from an analysis of the magnetization curves become lower in magnitude; however, the character of the temperature evolution of χAF is changed: now, dependence χAF( T) is an increasing function. The latter is typical for a system of AF particles with random orientation of the crystallographic axes. To correctly determine the antiferromagnetic susceptibility of AF nanoparticles (at least, ferrihydrite) and to search for effects related to the superantiferromagnetism effect, it is necessary to use in experiments the range of magnetic field significantly higher than that the standard value 60 kOe used in most experiments. The study of the temperature evolution of the magnetization curves shows that the observed crossover is due to the existence of small magnetic moments in the samples.

Introducing the VISAGE project - Visualization for Integrated Satellite, Airborne, and Ground-based data Exploration

NASA Astrophysics Data System (ADS)

Gatlin, P. N.; Conover, H.; Berendes, T.; Maskey, M.; Naeger, A. R.; Wingo, S. M.

2017-12-01

A key component of NASA's Earth observation system is its field experiments, for intensive observation of particular weather phenomena, or for ground validation of satellite observations. These experiments collect data from a wide variety of airborne and ground-based instruments, on different spatial and temporal scales, often in unique formats. The field data are often used with high volume satellite observations that have very different spatial and temporal coverage. The challenges inherent in working with such diverse datasets make it difficult for scientists to rapidly collect and analyze the data for physical process studies and validation of satellite algorithms. The newly-funded VISAGE project will address these issues by combining and extending nascent efforts to provide on-line data fusion, exploration, analysis and delivery capabilities. A key building block is the Field Campaign Explorer (FCX), which allows users to examine data collected during field campaigns and simplifies data acquisition for event-based research. VISAGE will extend FCX's capabilities beyond interactive visualization and exploration of coincident datasets, to provide interrogation of data values and basic analyses such as ratios and differences between data fields. The project will also incorporate new, higher level fused and aggregated analysis products from the System for Integrating Multi-platform data to Build the Atmospheric column (SIMBA), which combines satellite and ground-based observations into a common gridded atmospheric column data product; and the Validation Network (VN), which compiles a nationwide database of coincident ground- and satellite-based radar measurements of precipitation for larger scale scientific analysis. The VISAGE proof-of-concept will target "golden cases" from Global Precipitation Measurement Ground Validation campaigns. This presentation will introduce the VISAGE project, initial accomplishments and near term plans.

Implications of the earthquake cycle for inferring fault locking on the Cascadia megathrust

USGS Publications Warehouse

Pollitz, Fred; Evans, Eileen

2017-01-01

GPS velocity fields in the Western US have been interpreted with various physical models of the lithosphere-asthenosphere system: (1) time-independent block models; (2) time-dependent viscoelastic-cycle models, where deformation is driven by viscoelastic relaxation of the lower crust and upper mantle from past faulting events; (3) viscoelastic block models, a time-dependent variation of the block model. All three models are generally driven by a combination of loading on locked faults and (aseismic) fault creep. Here we construct viscoelastic block models and viscoelastic-cycle models for the Western US, focusing on the Pacific Northwest and the earthquake cycle on the Cascadia megathrust. In the viscoelastic block model, the western US is divided into blocks selected from an initial set of 137 microplates using the method of Total Variation Regularization, allowing potential trade-offs between faulting and megathrust coupling to be determined algorithmically from GPS observations. Fault geometry, slip rate, and locking rates (i.e. the locking fraction times the long term slip rate) are estimated simultaneously within the TVR block model. For a range of mantle asthenosphere viscosity (4.4 × 1018 to 3.6 × 1020 Pa s) we find that fault locking on the megathrust is concentrated in the uppermost 20 km in depth, and a locking rate contour line of 30 mm yr−1 extends deepest beneath the Olympic Peninsula, characteristics similar to previous time-independent block model results. These results are corroborated by viscoelastic-cycle modelling. The average locking rate required to fit the GPS velocity field depends on mantle viscosity, being higher the lower the viscosity. Moreover, for viscosity ≲ 1020 Pa s, the amount of inferred locking is higher than that obtained using a time-independent block model. This suggests that time-dependent models for a range of admissible viscosity structures could refine our knowledge of the locking distribution and its epistemic uncertainty.

Evaluation of a commercially‐available block for spatially fractionated radiation therapy

PubMed Central

Buckey, Courtney; Cashon, Ken; Gutierrez, Alonso; Esquivel, Carlos; Shi, Chengyu; Papanikolaou, Nikos

2010-01-01

In this paper, we present the dosimetric characteristics of a commercially‐produced universal GRID block for spatially fractioned radiation therapy. The dosimetric properties of the GRID block were evaluated. Ionization chamber and film measurements using both Kodak EDR2 and Gafchromic EBT film were performed in a solid water phantom to determine the relative output of the GRID block as well as its spatial dosimetric characteristics. The surface dose under the block and at the openings was measured using ultra thin TLDs. After introducing the GRID block into the treatment planning system, a treatment plan was created using the GRID block and also by creating a GRID pattern using the multi‐leaf collimator. The percent depth doses measured with film showed that there is a shift of the dmax towards shallower depths for both energies (6 MV and 18 MV) under investigation. It was observed that the skin dose at the GRID openings was higher than the corresponding open field by a factor as high as 50% for both photon energies. The profiles showed the transmission under the block was in the order of 15–20% for 6 MV and 30% for 18 MV. The MUs calculated for a real patient using the block were about 80% less than the corresponding MUs for the same plan using the multileaf collimator to define the GRID. Based on this investigation, this brass GRID compensator is a viable alternative to other solid compensators or MLC‐based fields currently in use. Its ease of creation and use give it decided advantages. Its ability to be created once and used for multiple patients (by varying the collimation of the linear accelerator jaws) makes it attractive from a cost perspective. We believe this compensator can be put to clinical use, and will allow more centers to offer GRID therapy to their patients. PACS number: 87.53.Mr

SU-F-T-75: Dosimetry Considerations in the Use of Hanging-Eye Block for Lesions of the Conjunctiva

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

Grelewicz, Z; Lee, B; Cutright, D

Purpose: Superficial lesions in the conjunctiva are frequently treated with en face electrons, using a hanging block to spare dose to the lens of the eye. Dose to the tumor and lens depend on the design and setup of the block and supporting apparatus. We performed in phantom measurements in order to characterize the dose sparing effects of the block as well as the under-dosing effect under the supporting apparatus for 6 MeV treatment. Methods: The commercial hanging block studied uses a 1.2 cm diameter tungsten cylinder supported by a 3 mm diameter acrylic rod. Point dose measurements under themore » hanging block, under an unblocked part of the field, and under the acrylic rod were performed using MOSFET detectors. In addition, EBT3 film was used for both PDD and profile measurements at a depth in phantom of 3 mm for both 105 and 103 cm SSD. Results: MOSFET measurements reported a dose reduction of 95% under the tungsten block when using an SSD of 103 cm, and 86% when using an SSD of 105 cm at a depth in phantom of 3 mm. Film measurements showed that the area under the acrylic rod may be under-dosed by as much as 30% when using 103 SSD. MOSFET measurements confirmed that when using an SSD of 103 cm, the area under the acrylic rod is under-dosed by up to 30% at 3mm depth, compared to the unblocked part of the field. Conclusion: The effectiveness of the commercial hanging block apparatus depends on setup, with 95% lens sparing possible with an SSD of 103 cm. This short SSD is necessary for sharp penumbra. At this SSD, substantial under-dosing under the acrylic support rod is possible. This must be mitigated with either feathering, or using an alternative method of support for the tungsten block.« less

Reconstruction of a Phreatic Explosion from Block Dispersion Modeling at King's Bowl, Idaho

NASA Astrophysics Data System (ADS)

Kobs-Nawotniak, S. E.; Sears, D. W. G.; Hughes, S. S.; Borg, C.; Sears, H.; Skok, J. R.; Elphic, R. C.; Lim, D. S. S.; Heldmann, J. L.; Haberle, C. W.; Guy, H.; Kobayashi, L.; Garry, B.; Neish, C.; Kim, K. J.

2014-12-01

King's Bowl (KB), located in Idaho's eastern Snake River Plain, was formed by a phreatic blast through a mostly-congealed lava lake. Blocks up to ~2m diameter were ejected from the vent to form a ballistic ejecta blanket extending radially more than 100m. The blocks on the western side of the KB fissure are extraordinarily well exposed, as the fine fraction was blown eastward by ambient winds during the explosion. We present preliminary modeling results using the western ballistic blocks of KB to calculate the energy of the eruption, and the water volume necessary to create the blast. This work is presented in conjunction with two other 2014 AGU conference abstracts submitted by NASA SSERVI funded FINESSE (Field Investigations to Enable Solar System Science and Exploration) team members: Hughes et al., which introduces the geology of KB and Sears et al., which discusses field observation and data trends. Results of this research are extensible to steam-driven pits on other solar system bodies, including those observed on Mars, Phobos, Deimos, and the asteroids. Over 600 blocks ranging from .2 to 2m in diameter were mapped using differential GPS and measured for 3 axial lengths and vesicularity. Mass calculations were corrected using a scaling factor determined from measurements of 100 blocks at KB, coupled with targeted density measurements. The dispersed block trajectories were modeled using a fourth order Runge-Kutta solution of the equations of motion to calculate suites of possible ejection speeds and angles. The resulting characteristic vent velocities were used to calculate the kinetic energy necessary to evacuate the crater at KB; energy required for fragmentation is neglected at this time. Total mass in the kinetic energy calculations was calculated by two separate methods: 1) current volume expression of the KB crater and 2) an additive solution of the ejecta field as determined from radial transect surveys. From the kinetic energy we calculated the pressure behind the eruption, leading to the quantity of water required to create the phreatic blast.

Crustal deformation characteristics of Sichuan-Yunnan region in China on the constraint of multi-periods of GPS velocity fields

NASA Astrophysics Data System (ADS)

Yue, Caiya; Dang, Yamin; Dai, Huayang; Yang, Qiang; Wang, Xiankai

2018-04-01

In order to obtain deformation parameters in each block of Sichuan-Yunnan Region (SYG) in China by stages and establish a dynamic model about the variation of the strain rate fields and the surface expansion in this area, we taken the Global Positioning System (GPS) sites velocity in the region as constrained condition and taken advantage of the block strain calculation model based on spherical surface. We also analyzed the deformation of the active blocks in the whole SYG before and after the Wenchuan earthquake, and analyzed the deformation of active blocks near the epicenter of the Wenchuan earthquake in detail. The results show that, (1) Under the effects of the carving from India plate and the crimping from the potential energy of Tibetan Plateau for a long time, there is a certain periodicity in crustal deformation in SYG. And the period change and the earthquake occurrence have a good agreement. (2) The differences in GPS velocity fields relative Eurasian reference frame shows that the Wenchuan earthquake and the Ya'an earthquake mainly affect the crustal movement in the central and southern part of SYG, and the average velocity difference is about 4-8 mm/a for the Wenchuan earthquake and 2-4 mm/a for the Ya'an earthquake. (3) For the Wenchuan earthquake, the average strain changed from 10 to 20 nanostrian/a before earthquake to 40-50 nanostrian/a after the earthquake, but before and after the Ya'an earthquake, the strain value increased from about 15 nanostrian/a to about 30 nanostrian/a. (4) The Wenchuan earthquake has changed the strain parameter of each active block more or less. Especially, the Longmen block and Chengdu block near the epicenter. The research provides fundamental material for the study of the dynamic mechanism of the push extrusion from the north-east of the India plate and the crimp from Qinghai Tibet Plateau, and it also provides support for the study of crustal stress variation and earthquake prediction in Sichuan Yunnan region.

Fabrication routes for one-dimensional nanostructures via block copolymers

NASA Astrophysics Data System (ADS)

Tharmavaram, Maithri; Rawtani, Deepak; Pandey, Gaurav

2017-05-01

Nanotechnology is the field which deals with fabrication of materials with dimensions in the nanometer range by manipulating atoms and molecules. Various synthesis routes exist for the one, two and three dimensional nanostructures. Recent advancements in nanotechnology have enabled the usage of block copolymers for the synthesis of such nanostructures. Block copolymers are versatile polymers with unique properties and come in many types and shapes. Their properties are highly dependent on the blocks of the copolymers, thus allowing easy tunability of its properties. This review briefly focusses on the use of block copolymers for synthesizing one-dimensional nanostructures especially nanowires, nanorods, nanoribbons and nanofibers. Template based, lithographic, and solution based approaches are common approaches in the synthesis of nanowires, nanorods, nanoribbons, and nanofibers. Synthesis of metal, metal oxides, metal oxalates, polymer, and graphene one dimensional nanostructures using block copolymers have been discussed as well.

Poly(cyclohexylethylene)- block-poly(ethylene oxide) block polymers for metal oxide templating

DOE PAGES

Schulze, Morgan W.; Sinturel, Christophe; Hillmyer, Marc A.

2015-09-01

A series of poly(cyclohexylethylene)- block-poly(ethylene oxide) (CEO) diblock copolymers were synthesized through tandem anionic polymerizations and heterogeneous catalytic hydrogenation. Solvent-annealed CEO diblock films were used to template dense arrays of inorganic oxide nanodots via simple spin coating of an inorganic precursor solution atop the ordered film. The substantial chemical dissimilarity of the two blocks enables (i) selective inclusion of the inorganic precursor within the PEO domain and (ii) the formation of exceptionally small feature sizes due to a relatively large interaction parameter estimated from mean-field analysis of the order–disorder transition temperatures of compositionally symmetric samples. UV/ozone treatment following incorporation producesmore » an ordered arrangement of oxide nanodots and simultaneously removes the block polymer template. However, we report the smallest particles (6 ± 1 nm) templated from a selective precursor insertion method to date using a block polymer scaffold.« less

FBCOT: a fast block coding option for JPEG 2000

NASA Astrophysics Data System (ADS)

Taubman, David; Naman, Aous; Mathew, Reji

2017-09-01

Based on the EBCOT algorithm, JPEG 2000 finds application in many fields, including high performance scientific, geospatial and video coding applications. Beyond digital cinema, JPEG 2000 is also attractive for low-latency video communications. The main obstacle for some of these applications is the relatively high computational complexity of the block coder, especially at high bit-rates. This paper proposes a drop-in replacement for the JPEG 2000 block coding algorithm, achieving much higher encoding and decoding throughputs, with only modest loss in coding efficiency (typically < 0.5dB). The algorithm provides only limited quality/SNR scalability, but offers truly reversible transcoding to/from any standard JPEG 2000 block bit-stream. The proposed FAST block coder can be used with EBCOT's post-compression RD-optimization methodology, allowing a target compressed bit-rate to be achieved even at low latencies, leading to the name FBCOT (Fast Block Coding with Optimized Truncation).

Heat Shield Employing Cured Thermal Protection Material Blocks Bonded in a Large-Cell Honeycomb Matrix

NASA Technical Reports Server (NTRS)

Zell, Peter

2012-01-01

A document describes a new way to integrate thermal protection materials on external surfaces of vehicles that experience the severe heating environments of atmospheric entry from space. Cured blocks of thermal protection materials are bonded into a compatible, large-cell honeycomb matrix that can be applied on the external surfaces of the vehicles. The honeycomb matrix cell size, and corresponding thermal protection material block size, is envisioned to be between 1 and 4 in. (.2.5 and 10 cm) on a side, with a depth required to protect the vehicle. The cell wall thickness is thin, between 0.01 and 0.10 in. (.0.025 and 0.25 cm). A key feature is that the honeycomb matrix is attached to the vehicle fs unprotected external surface prior to insertion of the thermal protection material blocks. The attachment integrity of the honeycomb can then be confirmed over the full range of temperature and loads that the vehicle will experience. Another key feature of the innovation is the use of uniform-sized thermal protection material blocks. This feature allows for the mass production of these blocks at a size that is convenient for quality control inspection. The honeycomb that receives the blocks must have cells with a compatible set of internal dimensions. The innovation involves the use of a faceted subsurface under the honeycomb. This provides a predictable surface with perpendicular cell walls for the majority of the blocks. Some cells will have positive tapers to accommodate mitered joints between honeycomb panels on each facet of the subsurface. These tapered cells have dimensions that may fall within the boundaries of the uniform-sized blocks.

The Big Mountain oil field, Ventura, California

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

Hall, E.A.

1967-06-02

The Big Mt. oil field is believed to be primarily a fault trap accumulation. All faults are hidden beneath the unconformity at the base of the Vaqueros Formation, or die out before reaching the surface. The Sespe Formation is divided into an upper sandy unit, a middle alternating sand and shale unit, and a lower sandy unit in the Big Mt. area. The producing zone is in the upper portion of the lower sandy unit. The sands are soft and friable, medium to coarse, and the reservoir characteristics are relatively good. The geology is similar to that observed in manymore » Sespe fields, such as the Oxnard and Montalvo oil fields, and the SE. portion of the South Mt. oil field. These fields are broken into many fault blocks and different production characteristics in each block. Good wells and poor ones are interspersed, with good wells downdip from poor ones and visa versa. The Big Mt. field is shallow, drilling and production costs are relatively inexpensive, and there is no royalty burden on the oil.« less

Distributed deformation and block rotation in 3D

NASA Technical Reports Server (NTRS)

Scotti, Oona; Nur, Amos; Estevez, Raul

1990-01-01

The authors address how block rotation and complex distributed deformation in the Earth's shallow crust may be explained within a stationary regional stress field. Distributed deformation is characterized by domains of sub-parallel fault-bounded blocks. In response to the contemporaneous activity of neighboring domains some domains rotate, as suggested by both structural and paleomagnetic evidence. Rotations within domains are achieved through the contemporaneous slip and rotation of the faults and of the blocks they bound. Thus, in regions of distributed deformation, faults must remain active in spite of their poor orientation in the stress field. The authors developed a model that tracks the orientation of blocks and their bounding faults during rotation in a 3D stress field. In the model, the effective stress magnitudes of the principal stresses (sigma sub 1, sigma sub 2, and sigma sub 3) are controlled by the orientation of fault sets in each domain. Therefore, adjacent fault sets with differing orientations may be active and may display differing faulting styles, and a given set of faults may change its style of motion as it rotates within a stationary stress regime. The style of faulting predicted by the model depends on a dimensionless parameter phi = (sigma sub 2 - sigma sub 3)/(sigma sub 1 - sigma sub 3). Thus, the authors present a model for complex distributed deformation and complex offset history requiring neither geographical nor temporal changes in the stress regime. They apply the model to the Western Transverse Range domain of southern California. There, it is mechanically feasible for blocks and faults to have experienced up to 75 degrees of clockwise rotation in a phi = 0.1 strike-slip stress regime. The results of the model suggest that this domain may first have accommodated deformation along preexisting NNE-SSW faults, reactivated as normal faults. After rotation, these same faults became strike-slip in nature.

Non-competitive liking for brands. No blocking in evaluative conditioning.

PubMed

Laane, Kristjan; Aru, Juhan; Dickinson, Anthony

2010-02-01

In the first experiment, we demonstrated evaluative conditioning using a novel across-modality procedure in which pictorial abstract brand logos acted as conditioned stimulus (CSs) and self-selected foods of different hedonic valence functioned as unconditioned stimuli (USs). We then investigated whether this form of learning of likes discriminates against redundant CSs using a blocking paradigm in the second experiment. The strength of evaluative conditioning accruing to the target CSs during compound training was unaffected by whether the other element of the compound was pretrained with a hedonic US. The observation that contingency learning about the target CS was blocked by the pretraining suggests that learning of likes and predictive learning are mediated by different processes. 2009 Elsevier Ltd. All rights reserved.

Assessing the associative deficit of older adults in long-term and short-term/working memory.

PubMed

Chen, Tina; Naveh-Benjamin, Moshe

2012-09-01

Older adults exhibit a deficit in associative long-term memory relative to younger adults. However, the literature is inconclusive regarding whether this deficit is attenuated in short-term/working memory. To elucidate the issue, three experiments assessed younger and older adults' item and interitem associative memory and the effects of several variables that might potentially contribute to the inconsistent pattern of results in previous studies. In Experiment 1, participants were tested on item and associative recognition memory with both long-term and short-term retention intervals in a single, continuous recognition paradigm. There was an associative deficit for older adults in the short-term and long-term intervals. Using only short-term intervals, Experiment 2 utilized mixed and blocked test designs to examine the effect of test event salience. Blocking the test did not attenuate the age-related associative deficit seen in the mixed test blocks. Finally, an age-related associative deficit was found in Experiment 3, under both sequential and simultaneous presentation conditions. Even while accounting for some methodological issues, the associative deficit of older adults is evident in short-term/working memory.

Improved 3-D turbomachinery CFD algorithm

NASA Technical Reports Server (NTRS)

Janus, J. Mark; Whitfield, David L.

1988-01-01

The building blocks of a computer algorithm developed for the time-accurate flow analysis of rotating machines are described. The flow model is a finite volume method utilizing a high resolution approximate Riemann solver for interface flux definitions. This block LU implicit numerical scheme possesses apparent unconditional stability. Multi-block composite gridding is used to orderly partition the field into a specified arrangement. Block interfaces, including dynamic interfaces, are treated such as to mimic interior block communication. Special attention is given to the reduction of in-core memory requirements by placing the burden on secondary storage media. Broad applicability is implied, although the results presented are restricted to that of an even blade count configuration. Several other configurations are presently under investigation, the results of which will appear in subsequent publications.

Sequential development of structural heterogeneity in the Granny Creek oil field of West Virginia

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

Wilson, T.H.; Zheng, L.; Shumaker, R.C.

1993-08-01

Analysis of Vibroseis and weight-drop seismic data over the Granny Creek oil field in the Appalachian foreland of West Virginia indicates that the field's development has been effected by episodic Paleozoic reactivation of fault blocks rooted in the Precambrian crystalline basement. The imprint of structures associated with the Rome trough penetrates the overlying Paleozoic sedimentary cover. Reactivation histories of individual fault blocks vary considerably throughout the Paleozoic. In general, the relative displacement of these basement fault blocks decrease exponentially during the Paleozoic; however, this pattern is interrupted by periods of increased tectonic activity and relative inversion of offsets along somemore » faults. The distribution of late-stage detached structures during the Alleghenian orogeny also appears, in part, to be controlled by mechanical anisotrophy within the detached section related to the reactivation of deeper structures in the crystalline basement. The net effect is a complex time-variable pattern of structures that partly controls the location of the reservoir and heterogeneity within the geometric framework of the reservoir. Structural heterogeneity in the Granny Creek area is subdivided on the basis of scale into structures associated with variations of oil production within the reservoir. Variations of production within the field are related, in part, to small detached structures and reactivated basement faults.« less

Crustal deformation mechanism in southeastern Tibetan Plateau: Insights from numerical modeling

NASA Astrophysics Data System (ADS)

Li, Y.; Liu, S.; Chen, L.

2017-12-01

The Indo-Asian collision developed the complicated crustal deformation around the southeastern Tibetan plateau. Numerous models have proposed to explain the crustal deformation, but the mechanism remains controversial, especially the increasing multi-geophysics data, which demonstrate the existence of lower velocity, lower resistivity and high conductivity, implying that lower crustal flow is responsible for the crustal deformation, arguing for the lower crust flow model. To address the relations between the crust flow and the surface deformation, we employ a three-dimensional viscoelastic finite model to investigate the possible influence on the surface deformation, and discuss the stress field distribution under the model. Our preliminary results suggest that lower crustal flow plays an important role in crustal deformation in southeastern Tibetan plateau. The best fitting is achieved when the flow velocity of the lower crust is approximately 10-11 mm/a faster than that of the upper crust. Crustal rheological properties affect regional crustal deformation, when the viscosity of the middle and lower crust in the South China block reaches 1022 and 1023 Pa.s, respectively; the predicted match observations well, especially for the magnitude within the South China block. The maximum principal stress field exhibits clear zoning, gradually shifting from an approximately east-west orientation in the northern Bayan Har block to southeast in the South China block, southwest in the western Yunnan block, and a radially divergent distribution in the Middle Yunnan and Southern Yunnan blocks.

Quasi-Steady Evolution of Hillslopes in Layered Landscapes: An Analytic Approach

NASA Astrophysics Data System (ADS)

Glade, R. C.; Anderson, R. S.

2018-01-01

Landscapes developed in layered sedimentary or igneous rocks are common on Earth, as well as on other planets. Features such as hogbacks, exposed dikes, escarpments, and mesas exhibit resistant rock layers adjoining more erodible rock in tilted, vertical, or horizontal orientations. Hillslopes developed in the erodible rock are typically characterized by steep, linear-to-concave slopes or "ramps" mantled with material derived from the resistant layers, often in the form of large blocks. Previous work on hogbacks has shown that feedbacks between weathering and transport of the blocks and underlying soft rock can create relief over time and lead to the development of concave-up slope profiles in the absence of rilling processes. Here we employ an analytic approach, informed by numerical modeling and field data, to describe the quasi-steady state behavior of such rocky hillslopes for the full spectrum of resistant layer dip angles. We begin with a simple geometric analysis that relates structural dip to erosion rates. We then explore the mechanisms by which our numerical model of hogback evolution self-organizes to meet these geometric expectations, including adjustment of soil depth, erosion rates, and block velocities along the ramp. Analytical solutions relate easily measurable field quantities such as ramp length, slope, block size, and resistant layer dip angle to local incision rate, block velocity, and block weathering rate. These equations provide a framework for exploring the evolution of layered landscapes and pinpoint the processes for which we require a more thorough understanding to predict their evolution over time.

Carbon Transfers and Emissions Following Harvest and Pile Burning in Coastal Douglas-fir Forests Determined from Analysis of High-Resolution UAV Imagery and Point Clouds and from Field Surveys.

NASA Astrophysics Data System (ADS)

Trofymow, J. A.; Gougeon, F.; Kelley, J. W.

2017-12-01

Forest carbon (C) models require knowledge on C transfers due to intense disturbances such as fire, harvest, and slash burning. In such events, live trees die and C transferred to detritus or exported as round wood. With burning, live and detrital C is lost as emissions. Burning can be incomplete, leaving wood, charred and scattered or in unburnt rings and piles. For harvests, all round wood volume is routinely measured, while dispersed and piled residue volumes are typically assessed in field surveys, scaled to a block. Recently, geospatial methods have been used to determine, for an entire block, piled residues using LiDAR or image point clouds (PC) and dispersed residues by analysis of high-resolution imagery. Second-growth Douglas-fir forests on eastern Vancouver Island were examined, 4 blocks at Oyster River (OR) and 2 at Northwest Bay (NB). OR blocks were cut winter 2011, piled spring 2011, field survey, aerial RGB imagery and LiDAR PC acquired fall 2011, piles burned, burn residues surveyed, and post-burn aerial RGB imagery acquired 2012. NB blocks were cut fall 2014, piled spring 2015, field survey, UAV RGB imagery and image PC acquired summer 2015, piles burned and burn residues surveyed spring 2016, and post-burn UAV RGB imagery and PC acquired fall 2016. Volume to biomass conversion used survey species proportions and wood density. At OR, round wood was 261.7 SE 13.1, firewood 1.7 SE 0.3, and dispersed residue by survey, 13.8 SE 3.6 tonnes dry mass (t dm) ha-1. Piled residues were 8.2 SE 0.9 from pile surveys vs. 25.0 SE 5.9 t dm ha-1 from LiDAR PC bulk pile volumes and packing ratios. Post-burn, piles lost 5.8 SE 0.5 from survey of burn residues vs. 18.2 SE 4.7 t dm ha-1 from pile volume changes using 2011 LiDAR PC and 2012 imagery. The percentage of initial merchantable biomass exported as round & fire wood, remaining as dispersed & piled residue, and lost to burning was, respectively, 92.5%, 5.5% and 2% using only field methods vs. 87%, 7% and 6% from dispersed residues surveys and LIDAR PC pile volumes. At NB, preliminary analysis shows the post-burn difference in 2015 to 2016 UAV PC pile volumes, was similar to that using 2015 UAV PC pile volume and 2016 orthophoto pile area burned, suggesting the two geospatial methods are comparable. Comparisons will be made for transfers in all 6 blocks using only field survey or geospatial methods.

A PERIPHERAL CHOLINERGIC PATHWAY MODULATES STRESS-INDUCED HYPERTHERMIA IN THE RAT EXPOSED TO AN OPEN FIELD.

EPA Science Inventory

Exposure to an open-field is psychologically stressful and leads to an elevation in core temperature (Tc). This increase in Tc associated with open-field is usually referred to as stress-induced hyperthermia (SIH) and can be blocked centrally with cyclooxygenase inhibitors suc...

A novel fractal image compression scheme with block classification and sorting based on Pearson's correlation coefficient.

PubMed

Wang, Jianji; Zheng, Nanning

2013-09-01

Fractal image compression (FIC) is an image coding technology based on the local similarity of image structure. It is widely used in many fields such as image retrieval, image denoising, image authentication, and encryption. FIC, however, suffers from the high computational complexity in encoding. Although many schemes are published to speed up encoding, they do not easily satisfy the encoding time or the reconstructed image quality requirements. In this paper, a new FIC scheme is proposed based on the fact that the affine similarity between two blocks in FIC is equivalent to the absolute value of Pearson's correlation coefficient (APCC) between them. First, all blocks in the range and domain pools are chosen and classified using an APCC-based block classification method to increase the matching probability. Second, by sorting the domain blocks with respect to APCCs between these domain blocks and a preset block in each class, the matching domain block for a range block can be searched in the selected domain set in which these APCCs are closer to APCC between the range block and the preset block. Experimental results show that the proposed scheme can significantly speed up the encoding process in FIC while preserving the reconstructed image quality well.

Prediction of the solubility of cucurbitacin drugs in self-associating poly(ethylene oxide)-b-poly(alpha-benzyl carboxylate epsilon-caprolactone) block copolymer with different tacticities using molecular dynamics simulation.

PubMed

Patel, Sarthak K; Lavasanifar, Afsaneh; Choi, Phillip

2010-01-01

Molecular dynamics (MD) simulation was used to investigate the solubility of two hydrophobic drugs Cucurbitacin B (CuB) and Cucurbitacin I (CuI) in poly(ethylene oxide)-b-poly(alpha-benzyl carboxylate epsilon-caprolactone) (PEO-b-PBCL) block copolymers with different tacticities. In particular, di-block copolymer with three different tacticities viz. PEO-b-iPBCL, PEO-b-sPBCL, and PEO-b-aPBCL were used. The solubility was quantified by calculating the corresponding Flory-Huggins interaction parameters (chi) using random binary mixture models with 10wt% of drug. The tacticity of the di-block copolymer was found to influence significantly the solubility of two drugs in it. In particular, based on MD simulation results, only PEO-b-sPBCL exhibited solubility while the other two did not. Given the fact that the drugs were shown to be soluble in PEO-b-PBCL experimentally, it is predicted that the tacticity of the di-block copolymer synthesized in experiment is syndiotactic. This predication matches well with the dominant ring opening polymerization of cyclic lactones to syndiotactic polymers by stannous octoate as catalyst used to prepare PEO-b-PBCL block copolymers in our previous experiments. The simulation results showed that the solubility of the drugs in PEO-b-sPBCL is attributed to the favorable intra-molecular interaction of the di-block copolymer and favorable intermolecular interaction between the di-block copolymer and the drugs. Radial distribution function analysis provides useful insights into the nature and type of the intermolecular interactions.

Proactive interference of open field on consummatory successive negative contrast.

PubMed

Justel, Nadia; Pautassi, Ricardo; Mustaca, Alba

2014-03-01

Reactivity to a reward is affected by prior experience with the different reinforcer values of that reward, a phenomenon known as incentive relativity, which can be studied using the consummatory succesive negative contrast (cSNC) paradigm, in which the performance of animals that receive a 4 % sucrose solution after trials on which they were exposed to 32 % sucrose is compared with that of subjects that always receive the 4 % sucrose solution. The exploration of a novel open field can enhance or block the acquisition of associative and nonassociative memories. The effect of open field on cSNC has not yet been explored. The main result of the present study was that open-field exposure significantly modified the expression of cSNC. Exposure to an open field 1 h but not immediately before the downshift interfered with the expression of cSNC. These animals drank more of the downshifted reward than did controls that were not exposed to the apparatus, and this behavior persisted for up to three recovery trials. This phenomenon was observed even when the animals were given a more protracted preshift phase and when the discrepancy between the preshift and shift incentive values of sucrose were increased. An open field also interfered with incentive downshift when open-field exposure occurred 6 h before the downshift, and repeated exposure to the apparatus did not deteriorate this effect. The present study adds to a growing body of literature that indicates that open-field exploration can interfere with memory formation.

Late Triassic closure of the Paleo-Tethys Ocean in Central Tibet implied by paleomagnetism of Middle Triassic lavas from the Qiantang block

NASA Astrophysics Data System (ADS)

Song, P.; Lin, D.; Lippert, P. C.; Li, Z.

2017-12-01

The closure of the Paleo-Tethys Ocean is a major event not only in the tectonic history of the Tibetan Plateau that pre-conditioned the plateau for subsequent orogenic events, but also in the paleogeographic evolution of eastern Pangea. Final closure of this equatorial ocean, however, remains disputed, with ages ranging from the Late Permian to the Middle Cretaceous; this huge discrepancy is largely the result of the lack of high-quality paleomagnetic data and ambiguous stratigraphic data from Mesozoic rocks from Central Tibet. A recent Late Triassic paleopole derived from lavas of the Qiangtang block suggests that the Paleo-Tethys Ocean must have closed between Middle and Late Triassic (Song et al., EPSL 2015). We test this prediction with a paleomagnetic study of Middle Triassic lavas from the Qiangtang block. These lavas were previously dated to Middle Triassic (ca. 242-240 Ma) using zircon U-Pb geochonology. Rock magnetic experiments demonstrate that hematite and magnetite are the main carriers of remanence. Progressive thermal and alternating field demagnetization successfully isolated stable characteristic remanent magnetizations. Although these directions pass fold tests, suggesting a primary magnetization, we are conducting additional rock magnetic and petrographic studies to verify the primary nature of this magnetization. If these directions are primary, then they establish the first lava-based paleomagnetic pole of Middle Triassic age from the Qiangtang block. This pole was located at 63.4°N, 198.8°E, A95=4.1° (N=27) and yields a paleolatitude of 22.7±4.1°N at the reference point (33.5°N, 92.0°E). A comparison of our new Middle Triassic pole from the Qiangtang block with coeval paleopoles from the North China (NCB) and Tarim blocks indicates that the Paleo-Tethys Ocean was approximately 5-10° of latitude ( 550-1100 km) wide during the Middle Triassic. Within the context of our previous work that demonstrated the Qiangtang, NCB, and Tarim blocks share similar paleomagnetic poles during the Late Triassic (ca. 210 Ma), we conclude that the Paleo-Tethys Ocean at the longitude of Qiangtang must have closed during the Late Triassic (ca. 210-240 Ma). These paleomagnetic results help clarify stratigraphic and geochemical observations of suturing within the heart of the proto-Tibetan Plateau.

Two cell cycle blocks caused by iron chelation of neuroblastoma cells: separating cell cycle events associated with each block.

PubMed

Siriwardana, Gamini; Seligman, Paul A

2013-12-01

Studies have presented evidence that besides the well described S phase block, treatment of cancer cell lines with the iron chelator deferrioxamine (DFO) also results in an earlier block in G1 phase. In this article, measurements of cell cycle regulatory proteins define this block at a very specific point in G1. DFO treatment results in markedly decreased cyclin A protein levels. Cyclin E levels that accumulate in early to mid-G1 are increased in cells treated with DFO as compared to the resting cells. The DFO S phase block is shown after cells are arrested at G1/S by (aphidicolin) then released into DFO. The same S phase block occurs with DFO treatment of a neuroblastoma cell line relatively resistant to the G1 DFO block. These experiments clearly differentiate the S phase DFO block from the earlier block pinpointed to a point in mid-G1, before G1/S when cyclin E protein increases but before increased cyclin A synthesis. Apoptosis was observed in cells inhibited by DFO at both cell cycle arrest points.

Intradomain phase transitions in flexible block copolymers with self-aligning segments.

PubMed

Burke, Christopher J; Grason, Gregory M

2018-05-07

We study a model of flexible block copolymers (BCPs) in which there is an enlthalpic preference for orientational order, or local alignment, among like-block segments. We describe a generalization of the self-consistent field theory of flexible BCPs to include inter-segment orientational interactions via a Landau-de Gennes free energy associated with a polar or nematic order parameter for segments of one component of a diblock copolymer. We study the equilibrium states of this model numerically, using a pseudo-spectral approach to solve for chain conformation statistics in the presence of a self-consistent torque generated by inter-segment alignment forces. Applying this theory to the structure of lamellar domains composed of symmetric diblocks possessing a single block of "self-aligning" polar segments, we show the emergence of spatially complex segment order parameters (segment director fields) within a given lamellar domain. Because BCP phase separation gives rise to spatially inhomogeneous orientation order of segments even in the absence of explicit intra-segment aligning forces, the director fields of BCPs, as well as thermodynamics of lamellar domain formation, exhibit a highly non-linear dependence on both the inter-block segregation (χN) and the enthalpy of alignment (ε). Specifically, we predict the stability of new phases of lamellar order in which distinct regions of alignment coexist within the single mesodomain and spontaneously break the symmetries of the lamella (or smectic) pattern of composition in the melt via in-plane tilt of the director in the centers of the like-composition domains. We further show that, in analogy to Freedericksz transition confined nematics, the elastic costs to reorient segments within the domain, as described by the Frank elasticity of the director, increase the threshold value ε needed to induce this intra-domain phase transition.

Intradomain phase transitions in flexible block copolymers with self-aligning segments

NASA Astrophysics Data System (ADS)

Burke, Christopher J.; Grason, Gregory M.

2018-05-01

We study a model of flexible block copolymers (BCPs) in which there is an enlthalpic preference for orientational order, or local alignment, among like-block segments. We describe a generalization of the self-consistent field theory of flexible BCPs to include inter-segment orientational interactions via a Landau-de Gennes free energy associated with a polar or nematic order parameter for segments of one component of a diblock copolymer. We study the equilibrium states of this model numerically, using a pseudo-spectral approach to solve for chain conformation statistics in the presence of a self-consistent torque generated by inter-segment alignment forces. Applying this theory to the structure of lamellar domains composed of symmetric diblocks possessing a single block of "self-aligning" polar segments, we show the emergence of spatially complex segment order parameters (segment director fields) within a given lamellar domain. Because BCP phase separation gives rise to spatially inhomogeneous orientation order of segments even in the absence of explicit intra-segment aligning forces, the director fields of BCPs, as well as thermodynamics of lamellar domain formation, exhibit a highly non-linear dependence on both the inter-block segregation (χN) and the enthalpy of alignment (ɛ). Specifically, we predict the stability of new phases of lamellar order in which distinct regions of alignment coexist within the single mesodomain and spontaneously break the symmetries of the lamella (or smectic) pattern of composition in the melt via in-plane tilt of the director in the centers of the like-composition domains. We further show that, in analogy to Freedericksz transition confined nematics, the elastic costs to reorient segments within the domain, as described by the Frank elasticity of the director, increase the threshold value ɛ needed to induce this intra-domain phase transition.

Influence of Chirality in Ordered Block Copolymer Phases

NASA Astrophysics Data System (ADS)

Prasad, Ishan; Grason, Gregory

2015-03-01

Block copolymers are known to assemble into rich spectrum of ordered phases, with many complex phases driven by asymmetry in copolymer architecture. Despite decades of study, the influence of intrinsic chirality on equilibrium mesophase assembly of block copolymers is not well understood and largely unexplored. Self-consistent field theory has played a major role in prediction of physical properties of polymeric systems. Only recently, a polar orientational self-consistent field (oSCF) approach was adopted to model chiral BCP having a thermodynamic preference for cholesteric ordering in chiral segments. We implement oSCF theory for chiral nematic copolymers, where segment orientations are characterized by quadrupolar chiral interactions, and focus our study on the thermodynamic stability of bi-continuous network morphologies, and the transfer of molecular chirality to mesoscale chirality of networks. Unique photonic properties observed in butterfly wings have been attributed to presence of chiral single-gyroid networks, this has made it an attractive target for chiral metamaterial design.

Flower synchrony, growth and yield enhancement of small type bitter gourd (Momordica charantia L.) through plant growth regulators and NPK fertilization.

PubMed

Mia, Baset M A; Islam, Md Serajul; Miah, Md Yunus; Das, M R; Khan, H I

2014-02-01

Assessment of growth regulator and NPK fertilization effects are important tools for flower stimulation and yield improvement in cucurbits. This investigation demonstrates the comparative male-female flower induction and fruit yield of small sized bitter gourd treated with NPK fertilizers and plant growth regulators. Namely, two experiments having three replicates were conducted in a Randomized Complete Block Design (RCBD) with NPK fertilization and plant growth regulators-GA3, NAA and Ethophon application on small sized bitter gourd-genotype BG5 at the research field of the Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU). In experiment 1, different doses of NPK fertilizers comprised of 10 treatments and in that of experiment 2, different levels of plant growth regulators indicated 10 treatments. The results indicated that application of different doses of NPK fertilizer and plant growth regulators significantly (< or = 0.05) influenced over the flower initiation and fruit setting. The application of N90-P45-K60 fertilizer along with Ethophon spraying resulted in the better yield of small sized bitter gourd.

[Experience with combined spinal and epidural anesthesia at cesarean section].

PubMed

Levinzon, A S; Taran, O I; Pura, K R; Mishchenko, G S; Mamaeva, N V

2006-01-01

The paper analyzes some experience gained in using various modes of regional anesthesia as an anesthetic appliance at cesarean sections and comparatively characterizes various types of central segmental blocks. The results of 213 cases of cesarean section performed under spinal or combined spinal and epidural anesthesia (CSEA) were generalized by the following parameters: block onset, maternal and fetal action, the quality of anesthesia and postoperative analgesia, which leads to the conclusion that CSEA is the method of choice.

A Shifted Block Lanczos Algorithm 1: The Block Recurrence

NASA Technical Reports Server (NTRS)

Grimes, Roger G.; Lewis, John G.; Simon, Horst D.

1990-01-01

In this paper we describe a block Lanczos algorithm that is used as the key building block of a software package for the extraction of eigenvalues and eigenvectors of large sparse symmetric generalized eigenproblems. The software package comprises: a version of the block Lanczos algorithm specialized for spectrally transformed eigenproblems; an adaptive strategy for choosing shifts, and efficient codes for factoring large sparse symmetric indefinite matrices. This paper describes the algorithmic details of our block Lanczos recurrence. This uses a novel combination of block generalizations of several features that have only been investigated independently in the past. In particular new forms of partial reorthogonalization, selective reorthogonalization and local reorthogonalization are used, as is a new algorithm for obtaining the M-orthogonal factorization of a matrix. The heuristic shifting strategy, the integration with sparse linear equation solvers and numerical experience with the code are described in a companion paper.

The intermixed-blocked effect in human perceptual learning is not the consequence of trial spacing.

PubMed

Mitchell, Chris; Nash, Scott; Hall, Geoffrey

2008-01-01

A robust finding in humans and animals is that intermixed exposure to 2 similar stimuli (AX/BX) results in better discriminability of those stimuli on test than does exposure to 2 equally similar stimuli in 2 separate blocks (CX_DX)--the intermixed-blocked effect. This intermixed-blocked effect may be an example of the superiority of spaced over massed practice; in the intermixed, but not the blocked exposure regime, each presentation of a given stimulus (e.g., AX) is separated from the next by the presentation of its partner (BX). Two experiments with human participants replicated the intermixed-blocked effect and showed that the effect was not due to the spacing of exposure trials. A mechanism for the intermixed-blocked effect is proposed, which combines theories from associative learning and memory. PsycINFO Database Record (c) 2008 APA, all rights reserved.

Eclogitic breccia from the Monviso ophiolite complex: new field and petrographic data

NASA Astrophysics Data System (ADS)

Locatelli, Michele; Verlaguet, Anne; Federico, Laura; Agard, Philippe

2015-04-01

The Monviso meta-ophiolite complex (Northern Italy, Western Alps) represents a coherent portion of oceanic lithosphere metamorphosed under eclogite facies conditions during the Alpine orogeny (2.6 GPa - 550°C, Lago Superiore Unit, Angiboust et al., 2011), and exhibits from bottom to top a thick serpentinite sole locally capped by metasediments, Mg-Al-rich metagabbros, then Fe-Ti-metagabbros capped by metabasalts. This section is disrupted by three main shear zones. Our study focusses on the Lower Shear Zone (LSZ), situated between the serpentinite sole (to the East) and the Mg-metagabbro bodies (to the West), and composed of blocks of both Fe-Ti and Mg-Al metagabbros embedded in a talc and tremolite-rich serpentinite matrix. Among these blocks, some were described as eclogitic breccias and interpreted as the result of a seismic rupture plane (Angiboust et al., 2012). These breccias correspond to blocks of Fe-Ti-metagabbros that were brecciated in eclogitic facies conditions (as attested by the omphacite + garnet ± lawsonite cement of the breccia) in a fluid-rich environment, as suggested by the abundance of lawsonite in the cement. Here we present new field data on the distribution and petrographic characterization of these eclogitic blocks in the LSZ. The aim of this work is twofold: (I) detailed mapping of the eclogitic block distribution along the LSZ, in order to determine precisely the extent and representativity of the breccias and (II) characterization of the brecciated blocks, at the outcrop scale, to explore the brecciation processes and structures. Between Pian del Re and Colle di Luca localities, the occurrence of eclogite blocks is uniform along the strike of the shear-zone, resulting in a 16 km-long belt of outcropping eclogitic bodies embedded in serpentinite matrix. The shear-zone width, by contrast, varies from 1.3 km to 0.8 km. Three types of eclogitic blocks can be distinguished: (1) intact (i.e., not brecciated) blocks of Fe-Ti-metagabbros restricted to the lower part of the shear zone, close to the serpentinite sole; (2) numerous brecciated Fe-Ti-metagabbros scattered in the intermediate to upper levels of the LSZ; (3) blocks showing compositional variations and complex structures, with boudins of intact Fe-Ti-metagabbros embedded in highly foliated and folded Mg-rich rocks bounded on one side by Fe-Ti-breccia planes. In some cases the full transition from intact to highly brecciated rock is recorded in the same block. Here, the contacts between intact metagabbros and breccia are characterized by about 1m-wide zones of non rotated clasts with diameter up to 80 cm, almost matrix-absent. The amount of matrix vs clast increases, associated with a reduction in the clast size and increasing clast rotation, over a few meters up to the end of the bodies. These particular blocks give us a unique opportunity to better characterize the brecciation processes. Different kinds of measurements were realized on the brecciated blocks: (1) block size, (2) clasts vs. matrix relative volumetric abundances, (3) dimension and shape ratio of clasts, and angle of misorientation between their elongation axis or internal foliations (for five selected blocks). Preliminary results show that the majority (82%) of mapped blocks have a diameter of less than 10 meters, with only 8% being larger than 20 meters. In the brecciated Fe-Ti gabbros the average content of matrix is 28%, while for blocks showing compositional variation it varies from zero to 30%. The angle of misorientation between clasts' foliation shows, instead, a chaotic distribution. Preliminary field data thus demonstrate that breccia blocks have to be considered as a constant feature along the LSZ rather than as an exception, and that further work is needed to determine whether they formed through pervasive brecciation (and potentially multiple events) or through a localized event and were later disrupted by ductile deformation along the LSZ.

Food Services 103, 203, 303.

ERIC Educational Resources Information Center

Manitoba Dept. of Education, Winnipeg. Div. of Vocational Education.

This curriculum guide provides 15 blocks/credits of instruction for a food services program. The program for grades 10-12 is designed to provide students with the foundation for a successful and safety-conscious career in the field of food services. Each of the three courses--Food Services 103, 203, and 303--consists of four blocks of one credit…

Realized gains from block-plot coastal Douglas-fir trials in the northern Oregon Cascades

Treesearch

Terrence Z. Ye; Keith J.S. Jayawickrama; J. Bradley St. Clair

2010-01-01

Realized gains for coastal Douglas-fir (Pseudotsuga menziesii var. menziesii) were evaluated using data collected from 15-year-old trees from five field trials planted in large block plots in the northern Oregon Cascades. Three populations with different genetic levels (elite--high predicted gain; intermediate--moderate predicted gain; and an...

Higher-order associative processing in Hermissenda suggests multiple sites of neuronal modulation.

PubMed

Rogers, R F; Matzel, L D

1996-01-01

Two important features of modern accounts of associative learning are (1) the capacity for contextual stimuli to serve as a signal for an unconditioned stimulus (US) and (2) the capacity for a previously conditioned (excitatory) stimulus to "block" learning about a redundant stimulus when both stimuli serve as a signal for the same US. Here, we examined the process of blocking, thought by some to reflect a cognitive aspect of classical conditioning, and its underlying mechanisms in the marine mollusc Hermissenda. In two behavioral experiments, a context defined by chemosensory stimuli was made excitatory by presenting unsignalled USs (rotation) in that context. The excitatory context subsequently blocked overt learning about a discrete conditioned stimulus (CS; light) paired with the US in that context. In a third experiment, the excitability of the B photoreceptors in the Hermissenda eye, which typically increases following light-rotation pairings, was examined in behaviorally blocked animals, as well as in animals that had acquired a normal CS-US association or animals that had been exposed to the CS and US unpaired. Both the behaviorally blocked and the "normal" learning groups exhibited increases in neuronal excitability relative to unpaired animals. However, light-induced multiunit activity in pedal nerves was suppressed following normal conditioning but not in blocked or unpaired control animals, suggesting that the expression of blocking is mediated by neuronal modifications not directly reflected in B-cell excitability, possibly within an extensive network of central light-responsive interneurons.

Adapting Local Features for Face Detection in Thermal Image.

PubMed

Ma, Chao; Trung, Ngo Thanh; Uchiyama, Hideaki; Nagahara, Hajime; Shimada, Atsushi; Taniguchi, Rin-Ichiro

2017-11-27

A thermal camera captures the temperature distribution of a scene as a thermal image. In thermal images, facial appearances of different people under different lighting conditions are similar. This is because facial temperature distribution is generally constant and not affected by lighting condition. This similarity in face appearances is advantageous for face detection. To detect faces in thermal images, cascade classifiers with Haar-like features are generally used. However, there are few studies exploring the local features for face detection in thermal images. In this paper, we introduce two approaches relying on local features for face detection in thermal images. First, we create new feature types by extending Multi-Block LBP. We consider a margin around the reference and the generally constant distribution of facial temperature. In this way, we make the features more robust to image noise and more effective for face detection in thermal images. Second, we propose an AdaBoost-based training method to get cascade classifiers with multiple types of local features. These feature types have different advantages. In this way we enhance the description power of local features. We did a hold-out validation experiment and a field experiment. In the hold-out validation experiment, we captured a dataset from 20 participants, comprising 14 males and 6 females. For each participant, we captured 420 images with 10 variations in camera distance, 21 poses, and 2 appearances (participant with/without glasses). We compared the performance of cascade classifiers trained by different sets of the features. The experiment results showed that the proposed approaches effectively improve the performance of face detection in thermal images. In the field experiment, we compared the face detection performance in realistic scenes using thermal and RGB images, and gave discussion based on the results.

Orientationally invariant metrics of apparent compartment eccentricity from double pulsed field gradient diffusion experiments.

PubMed

Jespersen, Sune Nørhøj; Lundell, Henrik; Sønderby, Casper Kaae; Dyrby, Tim B

2013-12-01

Pulsed field gradient diffusion sequences (PFG) with multiple diffusion encoding blocks have been indicated to offer new microstructural tissue information, such as the ability to detect nonspherical compartment shapes in macroscopically isotropic samples, i.e. samples with negligible directional signal dependence on diffusion gradients in standard diffusion experiments. However, current acquisition schemes are not rotationally invariant in the sense that the derived metrics depend on the orientation of the sample, and are affected by the interplay of sampling directions and compartment orientation dispersion when applied to macroscopically anisotropic systems. Here we propose a new framework, the d-PFG 5-design, to enable rotationally invariant estimation of double wave vector diffusion metrics (d-PFG). The method is based on the idea that an appropriate orientational average of the signal emulates the signal from a powder preparation of the same sample, where macroscopic anisotropy is absent by construction. Our approach exploits the theory of exact numerical integration (quadrature) of polynomials on the rotation group, and we exemplify the general procedure with a set consisting of 60 pairs of diffusion wave vectors (the d-PFG 5-design) facilitating a theoretically exact determination of the fourth order Taylor or cumulant expansion of the orientationally averaged signal. The d-PFG 5-design is evaluated with numerical simulations and ex vivo high field diffusion MRI experiments in a nonhuman primate brain. Specifically, we demonstrate rotational invariance when estimating compartment eccentricity, which we show offers new microstructural information, complementary to that of fractional anisotropy (FA) from diffusion tensor imaging (DTI). The imaging observations are supported by a new theoretical result, directly relating compartment eccentricity to FA of individual pores. Copyright © 2013 John Wiley & Sons, Ltd.

Acid rock drainage passive remediation using alkaline clay: Hydro-geochemical study and impacts of vegetation and sand on remediation.

PubMed

Plaza, Fernando; Wen, Yipei; Liang, Xu

2018-10-01

Acid rock drainage (ARD) is one of the most adverse environmental problems of the mine industry, especially in regions with an abundance of coal refuse (CR) deposits (e.g. the Northern Appalachian Coalfield in the USA) where surface and ground waters are affected by this pollution due to the acidity and high content of sulfates and heavy metals. This study explores the effectiveness of the ARD passive remediation method using alkaline clay (AC) through a series of static and long-term kinetic laboratory experiments (over three years) complemented with field measurements and geochemical modeling. Two important issues associated with this passive and auto-sustainable ARD remediation method were investigated: 1) the hydrogeochemical study of the mixture in terms of the percentages of AC and CR, and, 2) impacts of vegetation cover and a saturated sand barrier on the remediation. Both the field measurements and the samples used for the experiments came from a local coal waste site. Through the analysis of the field measurements and the outcome of the laboratory experiments and the geochemical modeling, alkaline clay proved to be an effective remediation material for ARD, in terms of achieving a neutral pH in the leachate and immobilization of sulfate and metals such as Fe, Mn, Cu, Zn, Ni, Pb, Cd, Co. Moreover, it has been demonstrated that the use of vegetation and a saturated sand barrier are beneficial. Vegetation acted as a phytoaccumulation/phytoextraction agent, causing an additional immobilization of metals. The saturated sand barrier blocked downward the oxygen and water diffusion, reducing pyrite oxidation rates. The proposed remediation approach ensures that the acidity consumption will likely occur before all the alkalinity is exhausted. Copyright © 2018 Elsevier B.V. All rights reserved.

On the origin of the electron blocking effect by an n-type AlGaN electron blocking layer

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

Zhang, Zi-Hui; Ji, Yun; Liu, Wei

2014-02-17

In this work, the origin of electron blocking effect of n-type Al{sub 0.25}Ga{sub 0.75}N electron blocking layer (EBL) for c+ InGaN/GaN light-emitting diodes has been investigated through dual-wavelength emission method. It is found that the strong polarization induced electric field within the n-EBL reduces the thermal velocity and correspondingly the mean free path of the hot electrons. As a result, the electron capture efficiency of the multiple quantum wells is enhanced, which significantly reduces the electron overflow from the active region and increases the radiative recombination rate with holes.

Miniature solid-state gas compressor

DOEpatents

Lawless, W.N.; Cross, L.E.; Steyert, W.A.

1985-05-07

A miniature apparatus for compressing gases is disclosed in which an elastomer disposed between two opposing electrostrictive or piezoelectric ceramic blocks, or between a single electrostrictive or piezoelectric ceramic block and a rigid surface, is caused to extrude into or recede from a channel defined adjacent to the elastomer in response to application or removal of an electric field from the blocks. Individual cells of blocks and elastomer are connected to effect a gas compression by peristaltic activation of the individual cells. The apparatus is self-valving in that the first and last cells operate as inlet and outlet valves, respectively. Preferred electrostrictive and piezoelectric ceramic materials are disclosed, and an alternative, non-peristaltic embodiment of the apparatus is described. 9 figs.

Miniature solid-state gas compressor

DOEpatents

Lawless, William N.; Cross, Leslie E.; Steyert, William A.

1985-01-01

A miniature apparatus for compressing gases is disclosed in which an elastomer disposed between two opposing electrostrictive or piezoelectric ceramic blocks, or between a single electrostrictive or piezoelectric ceramic block and a rigid surface, is caused to extrude into or recede from a channel defined adjacent to the elastomer in response to application or removal of an electric field from the blocks. Individual cells of blocks and elastomer are connected to effect a gas compression by peristaltic activation of the individual cells. The apparatus is self-valving in that the first and last cells operate as inlet and outlet valves, respectively. Preferred electrostrictive and piezoelectric ceramic materials are disclosed, and an alternative, non-peristaltic embodiment of the apparatus is described.

Single molecule magnets from magnetic building blocks

NASA Astrophysics Data System (ADS)

Kroener, W.; Paretzki, A.; Cervetti, C.; Hohloch, S.; Rauschenbach, S.; Kern, K.; Dressel, M.; Bogani, L.; M&üLler, P.

2013-03-01

We provide a basic set of magnetic building blocks that can be rationally assembled, similar to magnetic LEGO bricks, in order to create a huge variety of magnetic behavior. Using rare-earth centers and multipyridine ligands, fine-tuning of intra and intermolecular exchange interaction is demonstrated. We have investigated a series of molecules with monomeric, dimeric and trimeric lanthanide centers using SQUID susceptometry and Hall bar magnetometry. A home-made micro-Hall-probe magnetometer was used to measure magnetic hysteresis loops at mK temperatures and fields up to 17 T. All compounds show hysteresis below blocking temperatures of 3 to 4 K. The correlation of the assembly of the building blocks with the magnetic properties will be discussed.

Measuring health systems strength and its impact: experiences from the African Health Initiative.

PubMed

Sherr, Kenneth; Fernandes, Quinhas; Kanté, Almamy M; Bawah, Ayaga; Condo, Jeanine; Mutale, Wilbroad

2017-12-21

Health systems are essential platforms for accessible, quality health services, and population health improvements. Global health initiatives have dramatically increased health resources; however, funding to strengthen health systems has not increased commensurately, partially due to concerns about health system complexity and evidence gaps demonstrating health outcome improvements. In 2009, the African Health Initiative of the Doris Duke Charitable Foundation began supporting Population Health Implementation and Training Partnership projects in five sub-Saharan African countries (Ghana, Mozambique, Rwanda, Tanzania, and Zambia) to catalyze significant advances in strengthening health systems. This manuscript reflects on the experience of establishing an evaluation framework to measure health systems strength, and associate measures with health outcomes, as part of this Initiative. Using the World Health Organization's health systems building block framework, the Partnerships present novel approaches to measure health systems building blocks and summarize data across and within building blocks to facilitate analytic procedures. Three Partnerships developed summary measures spanning the building blocks using principal component analysis (Ghana and Tanzania) or the balanced scorecard (Zambia). Other Partnerships developed summary measures to simplify multiple indicators within individual building blocks, including health information systems (Mozambique), and service delivery (Rwanda). At the end of the project intervention period, one to two key informants from each Partnership's leadership team were asked to list - in rank order - the importance of the six building blocks in relation to their intervention. Though there were differences across Partnerships, service delivery and information systems were reported to be the most common focus of interventions, followed by health workforce and leadership and governance. Medical products, vaccines and technologies, and health financing, were the building blocks reported to be of lower focus. The African Health Initiative experience furthers the science of evaluation for health systems strengthening, highlighting areas for further methodological development - including the development of valid, feasible measures sensitive to interventions in multiple contexts (particularly in leadership and governance) and describing interactions across building blocks; in developing summary statistics to facilitate testing intervention effects on health systems and associations with health status; and designing appropriate analytic models for complex, multi-level open health systems.

Temporal–Spatial Surface Seasonal Mass Changes and Vertical Crustal Deformation in South China Block from GPS and GRACE Measurements

PubMed Central

He, Meilin; Shen, Wenbin; Chen, Ruizhi; Ding, Hao; Guo, Guangyi

2017-01-01

The solid Earth deforms elastically in response to variations of surface atmosphere, hydrology, and ice/glacier mass loads. Continuous geodetic observations by Global Positioning System (CGPS) stations and Gravity Recovery and Climate Experiment (GRACE) record such deformations to estimate seasonal and secular mass changes. In this paper, we present the seasonal variation of the surface mass changes and the crustal vertical deformation in the South China Block (SCB) identified by GPS and GRACE observations with records spanning from 1999 to 2016. We used 33 CGPS stations to construct a time series of coordinate changes, which are decomposed by empirical orthogonal functions (EOFs) in SCB. The average weighted root-mean-square (WRMS) reduction is 38% when we subtract GRACE-modeled vertical displacements from GPS time series. The first common mode shows clear seasonal changes, indicating seasonal surface mass re-distribution in and around the South China Block. The correlation between GRACE and GPS time series is analyzed which provides a reference for further improvement of the seasonal variation of CGPS time series. The results of the GRACE observations inversion are the surface deformations caused by the surface mass change load at a rate of about −0.4 to −0.8 mm/year, which is used to improve the long-term trend of non-tectonic loads of the GPS vertical velocity field to further explain the crustal tectonic movement in the SCB and surroundings. PMID:29301236

Lesson from Tungsten Leading Edge Heat Load Analysis in KSTAR Divertor

NASA Astrophysics Data System (ADS)

Hong, Suk-Ho; Pitts, Richard Anthony; Lee, Hyeong-Ho; Bang, Eunnam; Kang, Chan-Soo; Kim, Kyung-Min; Kim, Hong-Tack; ITER Organization Collaboration; Kstar Team Team

2016-10-01

An important design issue for the ITER tungsten (W) divertor and in fact for all such components using metallic plasma-facing elements and which are exposed to high parallel power fluxes, is the question of surface shaping to avoid melting of leading edges. We have fabricated a series of tungsten blocks with a variety of leading edge heights (0.3, 0.6, 1.0, and 2.0 mm), from the ITER worst case to heights even beyond the extreme value tested on JET. They are mounted into adjacent, inertially cooled graphite tile installed in the central divertor region of KSTAR, within the field of view of an infra-red (IR) thermography system with a spatial resolution to 0.4 mm/pixel. Adjustment of the outer divertor strike point position is used to deposit power on the different blocks in different discharges. The measured power flux density on flat regions of the surrounding graphite tiles is used to obtain the parallel power flux, q|| impinging on the various W blocks. Experiments have been performed in Type I ELMing H-mode with Ip = 600 kA, BT = 2 T, PNBI = 3.5 MW, leading to a hot attached divertor with typical pulse lengths of 10 s. Three dimensional ANSYS simulations using q|| and assuming geometric projection of the heat flux are found to be consistent with the observed edge loading. This research was partially supported by Ministry of Science, ICT, and Future Planning under KSTAR project.

Cool in the kitchen: Radiation, conduction, and the Newton ``hot block'' experiment

NASA Astrophysics Data System (ADS)

Silverman, Mark P.; Silverman, Christopher R.

2000-02-01

Despite frequent reference to Newton's law of cooling in physics and math books, the paper in which Newton reported this law is quite obscure and rarely cited. We have managed to acquire a copy of this paper and discuss the interesting experiment that Newton did in his kitchen. Surprisingly, the paper contains no procedural details or data of any experiments measuring the rate at which a hot object cools. We have performed our own kitchen experiments to investigate the cooling of (a) the burner of an electric range and (b) a block of Styrofoam. Newton's law provides a poor model for both systems, whose th! ! ermal energy loss we can much better understand by examining closely the effects of radiation and conduction.

Test Excavations at 3LA128. An Early Caddo Occupation on the Red River.

DTIC Science & Technology

1982-04-15

aberact entered in Block 20, It different frot Report) IS. SUPPLEMENTARY NOTES It. KEY WORDS (Continue on reverse side It necessary end Identify by... block number) ! l SITNT’ (CCOlMnue as reverse shb N ne"myaj dad identify by block nmbet) t7The Arkansas Acheological Survey tested site 37.A128 under...Purchase Order DACW29-81-M-0165 on the Field Revetment for the New Orleans District Office of the U.S. Army Corps of Engineers to gather data for

Tunable PhoXonic Band Gap Materials from Self-Assembly of Block Copoliymers and Colloidal Nanocrystals (NBIT Phase II)

DTIC Science & Technology

2011-05-06

electric fields. For that, we are going to use PS - b - P2VP block copolymers as a model system, utilizing the quite versatile chemistry of the P2VP ...displays. Our efforts at Hanyang have focused on tunable PBG materials self-assembled from polystyrene- b -poly(2-vinyl pyridine) ( PS - b - P2VP ) block...small angle x-ray scattering measurements during swelling of low molecular weight PS - P2VP polymers at the Cornell High Energy Synchrotron Source

The use of statistical tools in field testing of putative effects of genetically modified plants on nontarget organisms

PubMed Central

Semenov, Alexander V; Elsas, Jan Dirk; Glandorf, Debora C M; Schilthuizen, Menno; Boer, Willem F

2013-01-01

Abstract To fulfill existing guidelines, applicants that aim to place their genetically modified (GM) insect-resistant crop plants on the market are required to provide data from field experiments that address the potential impacts of the GM plants on nontarget organisms (NTO's). Such data may be based on varied experimental designs. The recent EFSA guidance document for environmental risk assessment (2010) does not provide clear and structured suggestions that address the statistics of field trials on effects on NTO's. This review examines existing practices in GM plant field testing such as the way of randomization, replication, and pseudoreplication. Emphasis is placed on the importance of design features used for the field trials in which effects on NTO's are assessed. The importance of statistical power and the positive and negative aspects of various statistical models are discussed. Equivalence and difference testing are compared, and the importance of checking the distribution of experimental data is stressed to decide on the selection of the proper statistical model. While for continuous data (e.g., pH and temperature) classical statistical approaches – for example, analysis of variance (ANOVA) – are appropriate, for discontinuous data (counts) only generalized linear models (GLM) are shown to be efficient. There is no golden rule as to which statistical test is the most appropriate for any experimental situation. In particular, in experiments in which block designs are used and covariates play a role GLMs should be used. Generic advice is offered that will help in both the setting up of field testing and the interpretation and data analysis of the data obtained in this testing. The combination of decision trees and a checklist for field trials, which are provided, will help in the interpretation of the statistical analyses of field trials and to assess whether such analyses were correctly applied. We offer generic advice to risk assessors and applicants that will help in both the setting up of field testing and the interpretation and data analysis of the data obtained in field testing. PMID:24567836

The use of statistical tools in field testing of putative effects of genetically modified plants on nontarget organisms.

PubMed

Semenov, Alexander V; Elsas, Jan Dirk; Glandorf, Debora C M; Schilthuizen, Menno; Boer, Willem F

2013-08-01

To fulfill existing guidelines, applicants that aim to place their genetically modified (GM) insect-resistant crop plants on the market are required to provide data from field experiments that address the potential impacts of the GM plants on nontarget organisms (NTO's). Such data may be based on varied experimental designs. The recent EFSA guidance document for environmental risk assessment (2010) does not provide clear and structured suggestions that address the statistics of field trials on effects on NTO's. This review examines existing practices in GM plant field testing such as the way of randomization, replication, and pseudoreplication. Emphasis is placed on the importance of design features used for the field trials in which effects on NTO's are assessed. The importance of statistical power and the positive and negative aspects of various statistical models are discussed. Equivalence and difference testing are compared, and the importance of checking the distribution of experimental data is stressed to decide on the selection of the proper statistical model. While for continuous data (e.g., pH and temperature) classical statistical approaches - for example, analysis of variance (ANOVA) - are appropriate, for discontinuous data (counts) only generalized linear models (GLM) are shown to be efficient. There is no golden rule as to which statistical test is the most appropriate for any experimental situation. In particular, in experiments in which block designs are used and covariates play a role GLMs should be used. Generic advice is offered that will help in both the setting up of field testing and the interpretation and data analysis of the data obtained in this testing. The combination of decision trees and a checklist for field trials, which are provided, will help in the interpretation of the statistical analyses of field trials and to assess whether such analyses were correctly applied. We offer generic advice to risk assessors and applicants that will help in both the setting up of field testing and the interpretation and data analysis of the data obtained in field testing.

Stress field rotation or block rotation: An example from the Lake Mead fault system

NASA Technical Reports Server (NTRS)

Ron, Hagai; Nur, Amos; Aydin, Atilla

1990-01-01

The Coulomb criterion, as applied by Anderson (1951), has been widely used as the basis for inferring paleostresses from in situ fault slip data, assuming that faults are optimally oriented relative to the tectonic stress direction. Consequently if stress direction is fixed during deformation so must be the faults. Freund (1974) has shown that faults, when arranged in sets, must generally rotate as they slip. Nur et al., (1986) showed how sufficiently large rotations require the development of new sets of faults which are more favorably oriented to the principal direction of stress. This leads to the appearance of multiple fault sets in which older faults are offset by younger ones, both having the same sense of slip. Consequently correct paleostress analysis must include the possible effect of fault and material rotation, in addition to stress field rotation. The combined effects of stress field rotation and material rotation were investigated in the Lake Meade Fault System (LMFS) especially in the Hoover Dam area. Fault inversion results imply an apparent 60 degrees clockwise (CW) rotation of the stress field since mid-Miocene time. In contrast structural data from the rest of the Great Basin suggest only a 30 degrees CW stress field rotation. By incorporating paleomagnetic and seismic evidence, the 30 degrees discrepancy can be neatly resolved. Based on paleomagnetic declination anomalies, it is inferred that slip on NW trending right lateral faults caused a local 30 degrees counter-clockwise (CCW) rotation of blocks and faults in the Lake Mead area. Consequently the inferred 60 degrees CW rotation of the stress field in the LMFS consists of an actual 30 degrees CW rotation of the stress field (as for the entire Great Basin) plus a local 30 degrees CCW material rotation of the LMFS fault blocks.

Multigrid Methods for the Computation of Propagators in Gauge Fields

NASA Astrophysics Data System (ADS)

Kalkreuter, Thomas

Multigrid methods were invented for the solution of discretized partial differential equations in order to overcome the slowness of traditional algorithms by updates on various length scales. In the present work generalizations of multigrid methods for propagators in gauge fields are investigated. Gauge fields are incorporated in algorithms in a covariant way. The kernel C of the restriction operator which averages from one grid to the next coarser grid is defined by projection on the ground-state of a local Hamiltonian. The idea behind this definition is that the appropriate notion of smoothness depends on the dynamics. The ground-state projection choice of C can be used in arbitrary dimension and for arbitrary gauge group. We discuss proper averaging operations for bosons and for staggered fermions. The kernels C can also be used in multigrid Monte Carlo simulations, and for the definition of block spins and blocked gauge fields in Monte Carlo renormalization group studies. Actual numerical computations are performed in four-dimensional SU(2) gauge fields. We prove that our proposals for block spins are “good”, using renormalization group arguments. A central result is that the multigrid method works in arbitrarily disordered gauge fields, in principle. It is proved that computations of propagators in gauge fields without critical slowing down are possible when one uses an ideal interpolation kernel. Unfortunately, the idealized algorithm is not practical, but it was important to answer questions of principle. Practical methods are able to outperform the conjugate gradient algorithm in case of bosons. The case of staggered fermions is harder. Multigrid methods give considerable speed-ups compared to conventional relaxation algorithms, but on lattices up to 184 conjugate gradient is superior.

Stress field rotation or block rotation: An example from the Lake Mead fault system

NASA Astrophysics Data System (ADS)

Ron, Hagai; Nur, Amos; Aydin, Atilla

1990-02-01

The Coulomb criterion, as applied by Anderson (1951), has been widely used as the basis for inferring paleostresses from in situ fault slip data, assuming that faults are optimally oriented relative to the tectonic stress direction. Consequently if stress direction is fixed during deformation so must be the faults. Freund (1974) has shown that faults, when arranged in sets, must generally rotate as they slip. Nur et al., (1986) showed how sufficiently large rotations require the development of new sets of faults which are more favorably oriented to the principal direction of stress. This leads to the appearance of multiple fault sets in which older faults are offset by younger ones, both having the same sense of slip. Consequently correct paleostress analysis must include the possible effect of fault and material rotation, in addition to stress field rotation. The combined effects of stress field rotation and material rotation were investigated in the Lake Meade Fault System (LMFS) especially in the Hoover Dam area. Fault inversion results imply an apparent 60 degrees clockwise (CW) rotation of the stress field since mid-Miocene time. In contrast structural data from the rest of the Great Basin suggest only a 30 degrees CW stress field rotation. By incorporating paleomagnetic and seismic evidence, the 30 degrees discrepancy can be neatly resolved. Based on paleomagnetic declination anomalies, it is inferred that slip on NW trending right lateral faults caused a local 30 degrees counter-clockwise (CCW) rotation of blocks and faults in the Lake Mead area. Consequently the inferred 60 degrees CW rotation of the stress field in the LMFS consists of an actual 30 degrees CW rotation of the stress field (as for the entire Great Basin) plus a local 30 degrees CCW material rotation of the LMFS fault blocks.

Revisit submergence of ice blocks in front of ice cover—an experimental study

NASA Astrophysics Data System (ADS)

Wang, Jun; Wu, Yi-fan; Sui, Jueyi

2018-04-01

The present paper studies the stabilities of ice blocks in front of an ice cover based on experiments carried out in laboratory by using four types of ice blocks with different dimensions. The forces acting on the ice blocks in front of the ice cover are analyzed. The critical criteria for the entrainment of ice blocks in front of the ice cover are established by considering the drag force caused by the flowing water, the collision force, and the hydraulic pressure force. Formula for determining whether or not an ice block will be entrained under the ice cover is derived. All three dimensions of the ice block are considered in the proposed formula. The velocities calculated by using the developed formula are compared with those of calculated by other formulas proposed by other researchers, as well as the measured flow velocities for the entrainment of ice blocks in laboratory. The fitting values obtained by using the derived formula agree well with the experimental results.

Clustering performances in the NBA according to players' anthropometric attributes and playing experience.

PubMed

Zhang, Shaoliang; Lorenzo, Alberto; Gómez, Miguel-Angel; Mateus, Nuno; Gonçalves, Bruno; Sampaio, Jaime

2018-04-20

The aim of this study was: (i) to group basketball players into similar clusters based on a combination of anthropometric characteristics and playing experience; and (ii) explore the distribution of players (included starters and non-starters) from different levels of teams within the obtained clusters. The game-related statistics from 699 regular season balanced games were analyzed using a two-step cluster model and a discriminant analysis. The clustering process allowed identifying five different player profiles: Top height and weight (HW) with low experience, TopHW-LowE; Middle HW with middle experience, MiddleHW-MiddleE; Middle HW with top experience, MiddleHW-TopE; Low HW with low experience, LowHW-LowE; Low HW with middle experience, LowHW-MiddleE. Discriminant analysis showed that TopHW-LowE group was highlighted by two-point field goals made and missed, offensive and defensive rebounds, blocks, and personal fouls; whereas the LowHW-LowE group made fewest passes and touches. The players from weaker teams were mostly distributed in LowHW-LowE group, whereas players from stronger teams were mainly grouped in LowHW-MiddleE group; and players that participated in the finals were allocated in the MiddleHW-MiddleE group. These results provide alternative references for basketball staff concerning the process of evaluating performance.