Trap Length Research Articles

OpenMP GNU and Intel Fortran programs for solving the time-dependent Gross–Pitaevskii equation

We present Open Multi-Processing (OpenMP) version of Fortran 90 programs for solving the Gross-Pitaevskii (GP) equation for a Bose-Einstein condensate in one, two, and three spatial dimensions, optimized for use with GNU and Intel compilers. We use the split-step Crank-Nicolson algorithm for imaginary- and real-time propagation, which enables efficient calculation of stationary and non-stationary solutions, respectively. The present OpenMP programs are designed for computers with multi-core processors and optimized for compiling with both commercially-licensed Intel Fortran and popular free open-source GNU Fortran compiler. The programs are easy to use and are elaborated with helpful comments for the users. All input parameters are listed at the beginning of each program. Different output files provide physical quantities such as energy, chemical potential, root-mean-square sizes, densities, etc. We also present speedup test results for new versions of the programs.

Simple, Direct Routes to Polymer Brush Traps and Nanostructures for Studies of Diffusional Transport in Supported Lipid Bilayers.

Patterned poly(oligo ethylene glycol) methyl ether methacrylate (POEGMEMA) brush structures may be formed by using a combination of atom-transfer radical polymerization (ATRP) and UV photopatterning. UV photolysis is used to selectively dechlorinate films of 4-(chloromethyl)phenyltrichlorosilane (CMPTS) adsorbed on silica surfaces, by exposure either through a mask or using a two-beam interferometer. Exposure through a mask yields patterns of carboxylic acid-terminated adsorbates. POEGMEMA may be grown from intact Cl initiators that were masked during exposure. Corrals, traps, and other structures formed in this way enable the patterning of proteins, vesicles, and, following vesicle rupture, supported lipid bilayers (SLBs). Bilayers adsorbed on the carboxylic acid-terminated surfaces formed by C–Cl bond photolysis in CMPTS exhibit high mobility. SLBs do not form on POEGMEMA. Using traps consisting of carboxylic acid-functionalized regions enclosed by POEGMEMA structures, electrophoresis may be observed in lipid bilayers containing a small amount of a fluorescent dye. Segregation of dye at one end of the traps was measured by fluorescence microscopy. The increase in the fluorescence intensity was found to be proportional to the trap length, while the time taken to reach the maximum value was inversely proportional to the trap length, indicating uniform, rapid diffusion in all of the traps. Nanostructured materials were formed using interferometric lithography. Channels were defined by exposure of CMPTS films to maxima in the interferogram, and POEGMEMA walls were formed by ATRP. As for the micrometer-scale patterns, bilayers did not form on the POEGMEMA structures, and high lipid mobilities were measured in the polymer-free regions of the channels.

Comparative Evaluation of Density Estimation Methods on Different Uninterrupted Roadway Facilities: Few Case Studies in India

Traffic density is one of the fundamental macroscopic characteristics and it is of prime importance when assessment of a facility has to be done based on both users as well as planner’s perspective. According to the Highway Capacity Manual (HCM), USA, for expressways and multilane roads, the Level-of-Service (LoS) has been defined taking density as the governing factor. Density is treated as the fundamental macroscopic spatial parameter of traffic flow, as it directly indicates the quality of traffic and ease with which one can drive. The present research study focuses on applicability of density estimation methods on multi-class, heterogeneous, non-lane based Indian traffic condition. In this research study, mid-block road sections namely, on Delhi-Gurgaon Expressway, Ahmedabad-Vadodara Expressway, National Highway (NH)-8 and urban arterial road in Chennai are considered. The expressways are the highest class of roads in Indian road network with different roadway, traffic conditions and with access control facilities. Delhi–Gurgoan Expressway is eight-lane divided facility and Ahemdabad –Vadodara Expressway is four-lane divided with 2.6 m paved shoulder. On the other hand, selected section on National Highway (NH8) is four-lane divided road. Real traffic data was collected through video-graphic survey on all these roads with different traffic conditions. HCVs (Heavy Commercial Vehicles) and MCVs (Multi-axle Commercial Vehicles) were the major traffic composition in congested regime. Thus, the present study focuses on the comparison of density estimation methods on different roadway and traffic conditions. The three methods to be employed for the purpose of estimating traffic density on the study section are: (1) using traffic flow fundamental equation relating speed, flow and density, HCM definition (2) using Cumulative input–output Plots (Input–Output method) (3) Eddie’s (x, t) method. This paper aims to empirically quantify the difference in the density estimation based on the aforementioned methods. Assuming input–output provides theoretical density, the errors in the estimation of density using fundamental equation under different traffic flow conditions are also quantified. In spite of growing body of literature disputing about the effectiveness and applicability of various density estimation methods, the key finding from this research indicates that all three abovementioned methods works very well under uncongested traffic flow condition. However, for oversaturated traffic conditions the density estimation using fundamental relationship has errors, primarily due to errors in estimation of the space mean speed since the vehicles which persisted within trap length for period longer than time-interval under consideration are not incorporated in the calculation, which is not the case for other two methods. Moreover, the research study concludes that smaller trap length (<100 m) can have errors in estimation of density values as compared to actual density values. The findings are useful for condition assessment of traffic flow for design and operation purposes.

Video Based Data Collection Process for Geometric Design Consistency Evaluation of Four-Lane Median Divided Horizontal Curves

Abstract Free flowing vehicle speed data are essential in the geometric design consistency evaluation of highways. Video based data acquisition technique can be used for the purpose. Further, in four-lane median divided highways, the vehicle needs to be monitored for the presence of other vehicles in the adjacent lane. The video log helps in vehicle tracking, vehicle classification, identification and monitoring free flow conditions along a stretch. Now, the vehicle speed is estimated from the travel time to cross known trap length. The accuracy of the speed data depends on the frame rate of the camera and trap length. The maximum possible error in estimating the travel time to cross known trap length is found to be one frame and its effect on vehicle speed estimation decreases with increase in trap length. However, observation (parallax) error increases with trap length. So it needs optimization. A field study is conducted with varying trap length to come up with the optimum values. The findings show that an optimal value of trap length is 15m. Also a video based data acquisition setup has been proposed to track free flowing vehicle. Finally, data set from video recording technique have been compared with standard data set. Results show that the speed measurements based on the proposed video based method are not statistically different from the standardized equipment.

Does Connectivity Index Of Transport Network Have Impact On Delay For Driver?

Abstract In Delhi city, road network and public transportation network comprehensive design have been rarely planned in long term taking care of appropriate projection of traffic demand. Short term localized treatment like constructing flyover, intersection etc., are shifting congestion from one part of network to other part of network, which is creating lot of traffic jam, environmental issues, in-spite of providing remedial solution at black sport. The parameters such as capacity, speed, distance, and travel related activity are key factors for the Connectivity Index of intersections. The objective of the study is to understand the Connectivity Index (CI) in terms of public transportation, and infrastructure system and its relationship with delay at network level explain by taking case study of capital city Delhi of India. The aim of the study is to develop a relationship between CI and delay for optimization of parameters such as speed, capacity for public transport as well infrastructure at network level. Nehru Place in South Delhi, India has selected to apply the methodology to derive CI and view the different link and node connectivity's in the form of connectivity index where average speed is found to be 15 km/h while, the delay (stopped delay) of particular section either at midblock or at junction is considered as speed less than 5 km/h. The study area/network consists of 6.9 km trap length which comprises of 6 junctions (nodes) which connects 6 road links (links). There are 12 public transit routes that connect 12 bus stops. The parameters such as speed, and delay were measured using the GPS device and videography, and capacity for public transport from DMITS. Capacity of roads were extracted from traffic data collected at all the road sections in the network. Travel activity representation of road density was calculated from the available zone maps of the study area and population density was calculated from the available census, 2011 data and the zonal area of the study area. The connectivity index was measured for the links and nodes. Analysis shows that the link/node having the highest connectivity has the more delay i.e. Nehru Place (link) 3 and Nehru Place bus stop (node) 3 has the highest connectivity with 3.64 and 0.89, delay in sec of link 3 and node 3 are 318 sec and 30 sec.

Observation of longitudinal quadrupole ion bunch oscillations in an electrostatic ion beam trap.

Ions in an ion bunch trapped inside an Electrostatic Ion Beam Trap (EIBT) exhibit collective oscillations within the bunch under the influence of an external driving force. These internal oscillations have been measured explicitly using a new method with a particle detector outside the EIBT. In this approach, the evolving ion bunch is monitored along the entire trap length, in contrast to the localized single point measurements that are often carried out in other techniques. In the present study, quadrupole oscillations have been measured for the first time in an EIBT along with the dipole oscillations that were measured previously. The frequency of the quadrupole oscillation is found to be about twice the dipole oscillation frequency. This is in agreement with the prediction of a theoretical model.

Continuous isolation of monocytes using a magnetophoretic-based microfluidic Chip.

Monocytes play an important role in the immune system and are responsible for phagocytizing and degrading foreign microorganisms in the body. The isolation of monocytes is important in various immunological applications such as in-vitro culture of dendritic cells. We present a magnetophoretic-based microfluidic chip for rapid isolation of highly purified, untouched monocytes from human blood by a negative selection method. This bioseparation platform integrates several unique features into a microfluidic device, including locally engineered magnetic field gradients and a continuous flow with a buffer switching scheme to improve the performance of the cell separation process. The results indicate high monocyte purity and recovery performances at a volumetric flow rate that is nearly an order of magnitude larger than comparable microfluidic devices reported in literature. In addition, a comprehensive 2-D computational modeling is performed to determine the cell trajectory and trapping length within the microfluidic chip. Furthermore, the effects of channel height, substrate thickness, cell size, number of beads per cell, and sample flow rate on the cell separation performance are studied.

Temperature dependence of small polaron population decays in iron-doped lithium niobate by Monte Carlo simulations

The population decay of light-induced small polarons in iron-doped lithium niobate is simulated by a Monte-Carlo method on the basis of Holstein's theory. The model considers random walks of both bound polarons (NbLi4+) and free polarons (NbNb4+) ending to deep traps (FeLi3+). The thermokinetic interplay between polaron species is introduced by trapping and de-trapping rates at niobium antisites (NbLi). The decay of the NbLi4+ population proceeds by three possible channels: direct trapping at FeLi3+ sites, hopping on niobium antisites and hopping on Nb regular sites after conversion to the free state. Up to three regimes, each one reflecting the predominance of one of these processes, appear with different activation energies in the Arrhenius plots of the decay time. The influence of FeLi and NbLi concentrations on the transition temperatures is evidenced. For both polaron species, the length of the final hop (trapping length) is found much larger than the usual hopping length and decreases at rising temperature. This trap size effect is a natural consequence of Holstein's theory and may explain some unclear features of polaron-related light-induced phenomena, such as the temperature-dependent stretching exponent of light-induced absorption decays and the anomalous increase of the photoconductivity at high doping levels.

On the properties of a bundle of flexible actin filaments in an optical trap.

We establish the statistical mechanics framework for a bundle of Nf living and uncrosslinked actin filaments in a supercritical solution of free monomers pressing against a mobile wall. The filaments are anchored normally to a fixed planar surface at one of their ends and, because of their limited flexibility, they grow almost parallel to each other. Their growing ends hit a moving obstacle, depicted as a second planar wall, parallel to the previous one and subjected to a harmonic compressive force. The force constant is denoted as the trap strength while the distance between the two walls as the trap length to make contact with the experimental optical trap apparatus. For an ideal solution of reactive filaments and free monomers at fixed free monomer chemical potential μ1, we obtain the general expression for the grand potential from which we derive averages and distributions of relevant physical quantities, namely, the obstacle position, the bundle polymerization force, and the number of filaments in direct contact with the wall. The grafted living filaments are modeled as discrete Wormlike chains, with F-actin persistence length ℓp, subject to discrete contour length variations ±d (the monomer size) to model single monomer (de)polymerization steps. Rigid filaments (ℓp = ∞), either isolated or in bundles, all provide average values of the stalling force in agreement with Hill's predictions Fs (H)=NfkBTln(ρ1/ρ1c)/d, independent of the average trap length. Here ρ1 is the density of free monomers in the solution and ρ1c its critical value at which the filament does not grow nor shrink in the absence of external forces. Flexible filaments (ℓp < ∞) instead, for values of the trap strength suitable to prevent their lateral escape, provide an average bundle force and an average trap length slightly larger than the corresponding rigid cases (few percents). Still the stalling force remains nearly independent on the average trap length, but results from the product of two strongly L-dependent contributions: the fraction of touching filaments ∝〈L〉(O.T.) (2) and the single filament buckling force ∝〈L〉(O.T.) (-2).

A dual detector Fourier transform electrostatic linear ion trap utilizing in-trap potential lift

Ion capture from an external nano-electrospray ionization source in an electrostatic linear ion trap has been effected by in-trap potential lift so as to avoid a time-dependent frequency drift of trapped ions. This phenomenon was observed when using mirror switching for capturing ions and compromised the mass resolution when using Fourier transform techniques for mass determination. A dual image charge detection approach was also implemented to compensate for losses in mass resolution associated with increasing the length of the electrostatic trap to accommodate the lift region. The potential lift approach for ion capture led to no detectable frequency shifts, thereby enabling the achievement of pressure-limited theoretical resolutions. For example, a resolution of roughly 11,000M/ΔM FWHM was observed for a carborane anion population of average m/z=520 at a transient length of 125ms. The use of the dual detector approach led to an increase (∼12%) in the ion frequencies used for mass analysis, which more than compensated for the effect of increasing the length of the electrostatic trap. Although the implementation of the potential lift approach and dual detectors were successful in their objectives, these changes resulted in a narrower m/z range for a single ion injection event relative to mirror switching. Furthermore, the dual detector approach resulted in a higher noise floor and a more complicated frequency spectrum due to asymmetries in the electric fields of the ion trap.

Measurement of the critical negative pressure inside traps of aquatic carnivorous Utricularia species

Firing and resetting of aquatic Utricularia traps are associated with water flows and pressure changes. A negative pressure of ca. −0.16bar is formed in reset traps, but its direct measurement is very difficult. We present a method of a gradual external application of negative pressure of −0.56 to −0.84mbars−1 through a fine capillary to cut off aquatic Utricularia traps to determine the critical negative pressure (CNP) at which the traps (located in air) fire and aspirate an air bubble. Using an electronic pressure sensor, we simulated the physiologically formed negative pressure needed for spontaneous trap firing in 15 aquatic Utricularia species of four generic sections. Mean CNP values ranged from −0.069bar in giant traps of U. reflexa to −0.346bar in U. dichotoma. The average in all 20 species or variants tested was −0.195±0.018bar, while that in 13 species or variants of the generic section Utricularia was −0.165±0.015bar and significantly differed from that of three populations of two species (U. dichotoma, U. volubilis) of the generic section Pleiochasia (−0.335±0.006bar). CNP differed significantly between giant and smaller traps of U. reflexa and young and old traps of U. vulgaris. Pooled data for 20 species or variants showed a significant negative linear correlation between trap length and CNP value. Within each species, high variability of the CNP was found: the lowest values were usually 2–3 times lower than the highest ones. This variability can represent three types of spontaneous firings described in the literature.

OpenMP Fortran and C programs for solving the time-dependent Gross–Pitaevskii equation in an anisotropic trap

We present new version of previously published Fortran and C programs for solving the Gross-Pitaevskii equation for a Bose-Einstein condensate with contact interaction in one, two and three spatial dimensions in imaginary and real time, yielding both stationary and non-stationary solutions. To reduce the execution time on multicore processors, new versions of parallelized programs are developed using Open Multi-Processing (OpenMP) interface. The input in the previous versions of programs was the mathematical quantity nonlinearity for dimensionless form of Gross-Pitaevskii equation, whereas in the present programs the inputs are quantities of experimental interest, such as, number of atoms, scattering length, oscillator length for the trap, etc. New output files for some integrated one- and two-dimensional densities of experimental interest are given. We also present speedup test results for the new programs.

Traffic Data Analysis Using Image Processing Technique on Delhi-Gurgaon Expressway

With the advancements in video image processing system (VIPS), detection mechanism has made a significant improvement over traditional methods for traffic data analysis. Traffic on Delhi-Gurgaon expressway is heterogeneous in nature with non-lane based behaviour. Moreover, automation and instrumentation are also not implemented. In view of this, TRaffic AnalyZer and EnumeratoR (TRAZER), a VIPS was used to process video-captured data on Delhi-Gurgaon expressway to check accuracy based on traffic count, speed and lateral placement. The motivation behind using TRAZER is to evaluate its efficiency and robustness for extracting micro and macro-level traffic parameters under heterogeneous traffic conditions. To achieve this, data were extracted manually on above parameters and compared with those obtained from TRAZER. The volume count data from TRAZER generated a lesser accuracy of 60% detection under heavy traffic conditions, using default parameters. Thus, refinements were carried out in the software as part of calibration: (i) redefining maximum and minimum detection widths for each vehicle category, and (ii) selecting the optimum trap length for reducing the occlusion effect, which increased the detection percentage as well as reduced the error. After implementing these refinements, 80% of the vehicles were detected. Further, relationships between vehicle speed and its lateral placement from median across road width, at a given point were also developed. The models were developed for both aggregate (considering all vehicles) and disaggregate (vehicle category-wise) levels. The polynomial relationship was found to be best fitted function to estimate vehicle speed based on its lateral placement.

Nonstationary model of an axisymmetric mirror trap with nonequilibrium plasma

The DOL nonstationary model intended to describe plasma processes in axisymmetric magnetic mirror traps is considered. The model uses averaging over the bounce period in order to take into account the dependence of plasma parameters on the coordinate along the facility axis. Examples of calculations of trap parameters by means of the DOL code based on this model are presented. Among the features of the DOL model, one can single out two points: first, the capability of calculating the terms of the collision integral with the use of a non-Maxwellian scattering function while evaluating the distribution function of fast ions and, second, concerning the background plasma, the capability of calculating the longitudinal particle and energy fluxes in confinement modes with the particle mean free path being on the order of the trap length. The influence of the scattering function approximation used to calculate the collision integral on the solution to the kinetic equation is analyzed. The dependences of plasma parameters on the power of heating injectors and the length of the fast-ion turning zone are presented as calculation examples. The longitudinal profile of the fusion reaction rate in the case of a trap with a long fast-ion turning zone is shown to depend strongly on the input parameters of the model.

Observation of Impact Ionization of Shallow States in Sub-Kelvin, High-Purity Germanium

We report on the observation of impact ionization processes involving shallow impurity states in a sub-Kelvin, high-purity n-type germanium detector similar to those used by direct detection dark matter experiments such as the Cryogenic Dark Matter Search. An optical fiber is used to generate packets of charge carriers near one surface of the detector. The charge carriers drift to the opposite surface by application of an electric field. The resulting drift current is measured by a high-speed charge amplifier. The onset of impact ionization for both electron and hole transport is clearly observed in the drift current as the applied electric field is increased above \(\approx \)5 V/cm. We present the effective charge collection efficiency and trapping length as a function of applied electric field for electrons and holes. We estimate the impact ionization cross section to be on the order of \(5\times 10^{-13}\,\mathrm {cm}^2\).

Main magnetic focus ion source: Basic principles, theoretical predictions and experimental confirmations

It is proposed to produce highly charged ions in the local potential traps formed by the rippled electron beam in a focusing magnetic field. In this method, extremely high electron current densities can be attained on short length of the ion trap. The design of very compact ion sources of the new generation is presented. The computer simulations predict that for such ions as, for example, Ne8+ and Xe44+, the intensities of about 109 and 106 ions per second, respectively, can be obtained. The experiments with pilot example of the ion source confirm efficiency of the suggested method. The X-ray emission from Ir59+, Xe44+ and Ar16+ ions was detected. The control over depth of the local ion trap is shown to be feasible.

Free Flow Speed Analysis of Two Lane Inter Urban Highways

Increasing vehicular traffic which demands development of road network length has been observed for the past many decades on Indian roads. In addition to this, improper road maintenance strategy has resulted in pavement failure causing disintegration and deterioration before the design life of pavement. This deterioration of pavement results in reduced Free-Flow Speed (FFS) and loss of roadway capacity. United States Highway Capacity Manual (US-HCM 2010) defined Free Flow Speed is the theoretical speed when density and flow rate on a study segment are both zero. One of the objectives of this study is to review various factors influencing FFS and various methods of estimation of Free Flow speed for Inter Urban two lane roads. Based on the literature review, it was found that the five principle parameters influencing the free flow speed are driver, vehicle, roadway, environmental related parameters, traffic operation and control related parameters. This study also reviewed various methodologies adopted for determining FFS considering these influencing parameters. This study developed a relationship between free flow speed and pavement distress parameters. In this regard, traffic data was collected by using video for 8 hours on a identified trap length (60mts) covering Two lane bidirectional inter-urban road sections in Haryana and Andhra Pradesh states. The study period encompassed 4 hours in the morning and 4 hours in the evening hours. Classified Traffic volume count coupled with entry and exit time of different vehicles was extracted on identified trap length at every five minute interval. The pavement distress data collected for the study sections was collected using Automated Road Survey System(ARSS). Based on the above collected data appropriate relationships between Roughness and Free Flow speed were formulated. Linear models were considered to develop the Free Flow Speed Equations for the study sections and these equations were validated on statistical grounds too.

Prey Capture Success by Established and Introduced Populations of the Venus Flytrap (Dionaea muscipula)

We examined whether the ecological function (i.e., prey capture) of a rare, endemic carnivorous plant, Venus flytrap ( Dionaea muscipula ), was maintained in managed habitats along the sand rims of Carolina bay wetlands at a preserve in the coastal plain of South Carolina, U.S.A. We hypothesized that prey capture would be similar between established and introduced plants because environmental conditions were similar. Number of traps, trap length, trap width, and prey length did not significantly differ between introduced and established populations, and most indicators of prey capture success significantly favored plants growing in introduced sites. Plants in introduced sites had almost 10% more closed traps, had significantly more traps with prey, had more traps with multiple prey items, and had a greater proportion of closed and total traps containing prey. When combined across sampling dates, ants and spiders composed the majority of captured invertebrates; spiders predominated in established sites while ants predominated in introduced sites. Prey availability on one date at a subset of sites was significantly greater in introduced sites. Our data supported the effectiveness of the clearing and transplanting restoration activity for Venus flytraps by showing that individual plants growing in introduced sites have similar structure and function as those in established sites. Consistently greater prey capture success by introduced plants likely contributed to their growth, although underlying reasons for differences in prey capture between introduced and established plants remain uncertain. Evaluating prey capture of carnivorous plant populations provides insight into mechanisms underlying restoration success.

Simulation studies of the behavior of positrons in a microtrap with long aspect ratio

The storage capacity of positrons in micro-Penning-Malmberg traps with large length to radius aspect ratios and radii of tens of microns was explored. Simulation studies were conducted with the WARP code and Charged Particle Optics program. A new design of the Penning-Malmberg trap consisting of an array of microtraps with substantially lower end electrode potential than conventional traps was considered. Simulations demonstrated each microtrap with 50 μm radius immersed in a 7T uniform magnetic field could store positrons indefinitely with a density of 1.6 × 1011cm-3 while the confinement voltage was only 10V. For microtraps with radii between 100 μm and 3 μm, the particle density scaled as r -2. Charge clouds developed the expected radial density distribution (that of a soft edge) and rigid rotation evolved to some extent. Plasma confinement time was independent of trap length.

Relationship between trap anatomy and function in Australian carnivorous bladderworts (Utricularia) of the subgenus Polypompholyx

The suction traps of carnivorous Utricularia species are hollow bladders of foliar origin which trap and digest small organisms. In this paper, the trap wall anatomy and thickness in nine Australian Utricularia species belonging to three generic sections (Pleiochasia, Polypompholyx, Tridentaria) within the subgen. Polypompholyx are described. It is hypothesized that there is a close relationship between Utricularia trap wall anatomy and functional trap characteristics – species with more than two cell layers in their trap walls are less effective at trap firing (i.e., water aspiration) and resetting (water pumping) than species with two-layered trap walls. The trap walls of all Utricularia species studied using light microscopy consisted of two to five cell layers. A distinct variation in the trap wall structure occurred not only within one generic Utricularia section, but even within one species and also different parts of one trap. Using an electronic position sensor to monitor trap thickness showed that in two clones of Utricularia dichotoma, both firing (41±2 and 46±3μmmm−1) and resetting rates per unit trap length (14±1μmmm−1 per 30min) were markedly lower than the mean values for 13 aquatic Utricularia species obtained from the literature (73±2 and 52±2μmmm−1, respectively). In conclusion, the number of cell layers in the trap wall may not in itself be decisive for the trap firing–resetting efficiency. The lag-period of water pumping by the trap, which can be caused by a different regulation mechanism of water pumping, is probably confined to the species from the Pleiochasia section in contrast to the aquatic species from the Utricularia section.