Pedestrian Flow Characteristics for Different Pedestrian Facilities and Situations

The pedestrian walking data collected at nineteen locations in five cities of India are analyzed in this paper. Pedestrian facilities are classified based on their width as sidewalk, wide-sidewalk and precincts. The analysis indicates that the pedestrian free flow speed is high on sidewalks (1.576 m/s) and low on precincts (1.340 m/s). The increase in width of the facility resulted in increased space available to a pedestrian, but reduced maximum flow rate and optimum density. It is found that the relationship between speed and density follows Underwood (exponential) model on sidewalk of varying widths and Greenshield’s (linear) model on a non-exclusive facility. Bi-directional flow on a facility affects the free flow speed and space available to the pedestrian adversely at high density. Squeezing effect at the centre and follow the predecessor near sides is observed under heavy bidirectional flow. The presence of a bottleneck reduces the free flow speed and maximum flow substantially. Pedestrians moved in layers at high density. Maximum flow rate is observed to be higher on the carriageway (2.067 ped/s) as compared to an exclusive pedestrian facility (1.493 ped/s)

Geomagnetic field variations at the equatorial electrojet station in Sri Lanka, Peredinia

The paper discusses the variations of the horizontal (<i>H</i>), vertical (<i>Z</i>) and eastward (<i>Y</i>) components of the geomagnetic field at Peredinia (PRD), an electrojet station in Sri Lanka, with the time of the day, season, sudden commencement (SSC) and during geomagnetic storms. The daily variation of <i>H</i> showed a large peak around midday. The daily variation of <i>Z</i> appeared to be almost a time gradient curve of the daily variation of <i>H</i>, showing a maximum around 09:00 LT (75° EMT) when the <i>H</i> field was increasing fastest and not at noon when Δ <i>H</i> was the maximum. Storm time variation of <i>H</i> resembled the variation of the <i>D<sub>st</sub></i> index but that of <i>Z</i> showed a large minimum about 2-3h before the time of minimum <i>D<sub>st</sub></i> or at the time of maximum time gradient of <i>D<sub>st</sub></i> variation. These features are compared with corresponding variations at the equatorial stations Trivandrum (TRD) in India, and remarkable similarity in all observations is noticed at PRD and TRD. It is suggested that the observed abnormal features of <i>Z</i> variations at electrojet stations in India-Sri Lanka are due to (i) direct effect of the ionospheric electrojet current (ii) the induction effect of the image current by the average spatially extended conductivity region and (iii) the induction current in the local subsurface conductor. It is suggested that the conductor responsible for the observed features in <i>Z</i> in India and Sri Lanka has to have extended spatial domain to latitudes well south of India, rather than confined to narrow Palk Strait

Co-axial dual-core resonant leaky fibre for optical amplifiers

We present a co-axial dual-core resonant leaky optical fibre design, in which the outer core is made highly leaky. A suitable choice of parameters can enable us to resonantly couple power from the inner core to the outer core. In a large-core fibre, such a resonant coupling can considerably increase the differential leakage loss between the fundamental and the higher order modes and can result in effective single-mode operation. In a small-core single-mode fibre, such a coupling can lead to sharp increase in the wavelength dependent leakage loss near the resonant wavelength and can be utilized for the suppression of amplified spontaneous emission and thereby gain equalization of an optical amplifier. We study the propagation characteristics of the fibre using the transfer matrix method and present an example of each, the large-mode-area design for high power amplifiers and the wavelength tunable leakage loss design for inherent gain equalization of optical amplifiers.Comment: 6 page

Analytic Element Method and Genetic Algorithm Based Models For Estimating Stream Bed Resistance

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Transport properties of Layer-Antiferromagnet CuCrS2: A possible thermoelectric material

The electrical, thermal conductivity and Seebeck coefficient of the quenched, annealed and slowly cooled phases of the layer compound CuCrS2 have been reported between 15K to 300K. We also confirm the antiferromagnetic transition at 40K in them by our magnetic measurements between 2K and 300K. The crystal flakes show a minimum around 100K in their in-plane resistance behavior. For the polycrystalline pellets the resistivity depends on their flaky texture and it attains at most 10 to 20 times of the room temperature value at the lowest temperature of measurement. The temperature dependence is complex and no definite activation energy of electronic conduction can be discerned. We find that the Seebeck coefficient is between 200-450 microV/K and is unusually large for the observed resistivity values of between 5-100 mOhm-cm at room temperature. The figure of merit ZT for the thermoelectric application is 2.3 for our quenched phases, which is much larger than 1 for useful materials. The thermal conductivity K is mostly due to lattice conduction and is reduced by the disorder in Cu- occupancy in our quenched phase. A dramatic reduction of electrical and thermal conductivity is found as the antiferromagnetic transition is approached from the paramagnetic region, and K subsequently rises in the ordered phase. We discuss the transport properties as being similar to a doped Kondo-insulator

Motion of rotatory molecular motor and chemical reaction rate

We examine the dependence of the physical quantities of the rotatory molecular motor, such as the rotation velocity and the proton translocation rate, on the chemical reaction rate using the model based only on diffusion process. A peculiar behavior of proton translocation is found and the energy transduction efficiency of the motor protein is enhanced by this behavior. We give a natural explanation that this behavior is universal when certain inequalities between chemical reaction rates hold. That may give a clue to examine whether the motion of the molecular motor is dominated by diffusion process or not.Comment: 12 pages, 8 figure

Sensors for Harsh Environment: Radiation Resistant FBG Sensor System

This paper presents radiation resistant characteristics of fibre Bragg grating (FBG) sensors written in a photosensitive fiber and connected to a silica core radiation resistant optical fibre, aiming to develop a sensor system suitable for both sensing and data transmission in harsh environment. The silica core fluorine-down-doped clad optical fibre has been specifically designed and fabricated for this study using the modified chemical vapor deposition technique. Key waveguide parameters, including the width of the fluorine doped inner cladding have been optimized to obtain a low loss (<;0.2 dB/km) at the operating wavelength region of 1550 nm. The fibre fabrication process, mainly the deposition condition, has also been optimized to achieve smooth deposition and sintering of silica core layers, to minimize radiation induced absorption. As a result, radiation induced absorption of ~2.2 dB/km at 1550 nm under accumulated dose of 25 MRad at dose rate of 0.39 MRad/hr has been successfully achieved. To create an effective sensor system for harsh environmental conditions, this specialty fibre is connected to a number of FBGs (sensors) fabricated in photosensitive fibres prior to their extensive evaluations by being exposed to different accumulated dose of gamma radiation. Their corresponding Bragg wavelength shifts (BWS) and peak amplitudes were continuously monitored. It was found that the radiation induced BWS can be greatly reduced by shielding the sensors using stainless steel tubing. The temperature sensitivity and peak amplitude were found to be largely unchanged before and after exposure to Gamma radiation of 25 MRad which shows their potential use for temperature measurements in radiation environments with an uncertainty of around 0.1 °C

Genetic diversity of Mycobacterium tuberculosis in Peru and exploration of phylogenetic associations with drug resistance.

BACKGROUND: There is limited available data on the strain diversity of M tuberculosis in Peru, though there may be interesting lessons to learn from a setting where multidrug resistant TB has emerged as a major problem despite an apparently well-functioning DOTS control programme. METHODS: Spoligotyping was undertaken on 794 strains of M tuberculosis collected between 1999 and 2005 from 553 community-based patients and 241 hospital-based HIV co-infected patients with pulmonary tuberculosis in Lima, Peru. Phylogenetic and epidemiologic analyses permitted identification of clusters and exploration of spoligotype associations with drug resistance. RESULTS: Mean patient age was 31.9 years, 63% were male and 30.4% were known to be HIV+. Rifampicin mono-resistance, isoniazid mono-resistance and multidrug resistance (MDR) were identified in 4.7%, 8.7% and 17.3% of strains respectively. Of 794 strains from 794 patients there were 149 different spoligotypes. Of these there were 27 strains (3.4%) with novel, unique orphan spoligotypes. 498 strains (62.7%) were clustered in the nine most common spoligotypes: 16.4% SIT 50 (clade H3), 12.3% SIT 53 (clade T1), 8.3% SIT 33 (LAM3), 7.4% SIT 42 (LAM9), 5.5% SIT 1 (Beijing), 3.9% SIT 47 (H1), 3.0% SIT 222 (clade unknown), 3.0% SIT1355 (LAM), and 2.8% SIT 92 (X3). Amongst HIV-negative community-based TB patients no associations were seen between drug resistance and specific spoligotypes; in contrast HIV-associated MDRTB, but not isoniazid or rifampicin mono-resistance, was associated with SIT42 and SIT53 strains. CONCLUSION: Two spoligotypes were associated with MDR particularly amongst patients with HIV. The MDR-HIV association was significantly reduced after controlling for SIT42 and SIT53 status; residual confounding may explain the remaining apparent association. These data are suggestive of a prolonged, clonal, hospital-based outbreak of MDR disease amongst HIV patients but do not support a hypothesis of strain-specific propensity for the acquisition of resistance-conferring mutations

Modulating Glutathione Thiol Status Alters Pancreatic β-cell Morphogenesis in the Developing Zebrafish (Danio rerio) Embryo

Emerging evidence suggests that redox-active chemicals perturb pancreatic islet development. To better understand potential mechanisms for this, we used zebrafish (Danio rerio) embryos to investigate roles of glutathione (GSH; predominant cellular redox buffer) and the transcription factor Nrf2a (Nfe2l2a; zebrafish Nrf2 coortholog) in islet morphogenesis. We delineated critical windows of susceptibility to redox disruption of beta-cell morphogenesis, interrogating embryos at 24, 48 and 72 h post fertilization (hpf) and visualized Nrf2a expression in the pancreas using whole-mount immunohistochemistry at 96 hpf. Chemical GSH modulation at 48 hpf induced significant islet morphology changes at 96 hpf. Pro-oxidant exposures to tert-butylhydroperoxide (77.6 mu M; 10-min at 48 hpf) or tert-butylhydroquinone (1 mu M; 48-56 hpf) decreased beta-cell cluster area at 96 hpf. Conversely, exposures to antioxidant N-acetylcysteine (bolsters GSH pools; 100 mu M; 48-72 hpf) or sulforaphane (activates Nrf2a; 20 mu M; 48-72 hpf) significantly increased islet areas. Nrf2a was also stabilized in beta-cells: 10-min exposures to 77.6 mu M tert-butylhydroperoxide significantly increased Nrf2a protein compared to control islet cells that largely lack stabilized Nrf2a; 10-min exposures to higher (776 mu M) tert-butylhydroperoxide concentration stabilized Nrf2a throughout the pancreas. Using biotinylated-GSH to visualize in situ protein glutathionylation, islet cells displayed high protein glutathionylation, indicating oxidized GSH pools. The 10-min high (776 mu M) tert-butylhydroperoxide exposure (induced Nrf2a globally) decreased global protein glutathionylation at 96 hpf. Mutant fish expressing inactive Nrf2a were protected against tert-butylhydroperoxide-induced abnormal islet morphology. Our data indicate that disrupted redox homeostasis and Nrf2a stabilization during pancreatic beta-cell development impact morphogenesis, with implications for disease states at later life stages. Our work identifies a potential molecular target (Nrf2) that mediates abnormal beta-cell morphology in response to redox disruptions. Moreover, our findings imply that developmental exposure to exogenous stressors at distinct windows of susceptibility could diminish the reserve redox capacity of beta-cells, rendering them vulnerable to later-life stresses and disease