High-resolution imaging spectroscopy of two micro-pores and an arch filament system in a small emerging-flux region

Aims. The purpose of this investigation is to characterize the temporal evolution of an emerging flux region, the associated photospheric and chromospheric flow fields, and the properties of the accompanying arch filament system. Methods. This study is based on imaging spectroscopy with the G\"ottingen Fabry-P\'erot Interferometer at the Vacuum Tower Telescope, on 2008 August 7. Cloud model (CM) inversions of line scans in the strong chromospheric absorption H$\alpha$ line yielded CM parameters, which describe the cool plasma contained in the arch filament system. Results. The observations cover the decay and convergence of two micro-pores with diameters of less than one arcsecond and provide decay rates for intensity and area. The photospheric horizontal flow speed is suppressed near the two micro-pores indicating that the magnetic field is sufficiently strong to affect the convective energy transport. The micro-pores are accompanied by an arch filament system, where small-scale loops connect two regions with H$\alpha$ line-core brightenings containing an emerging flux region with opposite polarities. The chromospheric velocity of the cloud material is predominantly directed downwards near the footpoints of the loops with velocities of up to 12 km/s, whereas loop tops show upward motions of about 3 km/s. Conclusions. Micro-pores are the smallest magnetic field concentrations leaving a photometric signature in the photosphere. In the observed case, they are accompanied by a miniature arch filament system indicative of newly emerging flux in the form of $\Omega$-loops. Flux emergence and decay take place on a time-scale of about two days, whereas the photometric decay of the micro-pores is much more rapid (a few hours), which is consistent with the incipient submergence of $\Omega$-loops. The results are representative for the smallest emerging flux regions still recognizable as such.Comment: 15 pages, 16 figures, 3 tables, published in A&

NOViSE: a virtual natural orifice transluminal endoscopic surgery simulator

Purpose: Natural Orifice Transluminal Endoscopic Surgery (NOTES) is a novel technique in minimally invasive surgery whereby a flexible endoscope is inserted via a natural orifice to gain access to the abdominal cavity, leaving no external scars. This innovative use of flexible endoscopy creates many new challenges and is associated with a steep learning curve for clinicians. Methods: We developed NOViSE - the first force-feedback enabled virtual reality simulator for NOTES training supporting a flexible endoscope. The haptic device is custom built and the behaviour of the virtual flexible endoscope is based on an established theoretical framework – the Cosserat Theory of Elastic Rods. Results: We present the application of NOViSE to the simulation of a hybrid trans-gastric cholecystectomy procedure. Preliminary results of face, content and construct validation have previously shown that NOViSE delivers the required level of realism for training of endoscopic manipulation skills specific to NOTES Conclusions: VR simulation of NOTES procedures can contribute to surgical training and improve the educational experience without putting patients at risk, raising ethical issues or requiring expensive animal or cadaver facilities. In the context of an experimental technique, NOViSE could potentially facilitate NOTES development and contribute to its wider use by keeping practitioners up to date with this novel surgical technique. NOViSE is a first prototype and the initial results indicate that it provides promising foundations for further development

Observations of solar small-scale magnetic flux-sheet emergence

Aims. Moreno-Insertis et al. (2018) recently discovered two types of flux emergence in their numerical simulations: magnetic loops and magnetic sheet emergence. Whereas magnetic loop emergence has been documented well in the last years, by utilising high-resolution full Stokes data from ground-based telescopes as well as satellites, magnetic sheet emergence is still an understudied process. We report here on the first clear observational evidence of a magnetic sheet emergence and characterise its development. Methods. Full Stokes spectra from the Hinode spectropolarimeter were inverted with the SIR code to obtain solar atmospheric parameters such as temperature, line-of-sight velocities and full magnetic field vector information. Results. We analyse a magnetic flux emergence event observed in the quiet-sun internetwork. After a large scale appearance of linear polarisation, a magnetic sheet with horizontal magnetic flux density of up to 194 Mx/cm$^{2}$ hovers in the low photosphere spanning a region of 2 to 3 arcsec. The magnetic field azimuth obtained through Stokes inversions clearly shows an organised structure of transversal magnetic flux density emerging. The granule below the magnetic flux-sheet tears the structure apart leaving the emerged flux to form several magnetic loops at the edges of the granule. Conclusions. A large amount of flux with strong horizontal magnetic fields surfaces through the interplay of buried magnetic flux and convective motions. The magnetic flux emerges within 10 minutes and we find a longitudinal magnetic flux at the foot points of the order of $\sim$$10^{18}$ Mx. This is one to two orders of magnitude larger than what has been reported for small-scale magnetic loops. The convective flows feed the newly emerged flux into the pre-existing magnetic population on a granular scale.Comment: 6 pages, 5 figures, accepted as a letter in A&

Design and Implementation of GSM Based Transformer Phase Monitoring System

In electric power distribution, transformers used in the process of distributing electric power to the final consumers which include industries and residents stand chances to fail due to overloading. Most often, fuses are the major components that fail in other to protect the transformer from severe damage. In situation like this it is deemed necessary for electric distribution company personnel to be notified of such failure as a smart response in other to bring a quick power restoration to the community or area affected. In this work, the design and implementation of a transformer phase monitoring system, which continuously check for blown fuses on each phases of the distribution transformer was carried out. The system promptly reports any transformer with blown J&P fuse via a preprogrammed SMS which will state the location of the transformer and the open phase. This system consists of “blown fuse circuit detectors” each connected across the fuse of each phase of the transformer. The detector was designed around an optocoupler and an Operational Amplifier (LM324) functioned to detect an open fuse. PIC16F876A was used under a program written in mikrobasic to process the output of the “blown fuse detectors”. If any open fuse was detected, it generates control signal to a SMS control unit consisting of a SAGEM mobile phone and an 8051 microcontroller. The SMS control unit sends an SMS to the distribution company as a failure notification, using AT commands over RS232 serial interface of the system. The system was designed and tested and it was found to work satisfactorily

Biodegradation of Crude Oil by Penicillin sp and Mortierella sp. Isolated from Oil-Contaminated Soil in Auto Mechanic Workshops

Biodegrading capability of fungi isolated from oil-contaminated soil in three auto-mechanic workshops in Minna, Nigeria was determined by mycelial extension rate measurement method. Penicillium strain 8 I 0 IF, 8201 F and B202F and Mortierel/a strain B I 002F were identified as best crude oil (lagoma light) degraders compared to the other isolates such Aspergillus strain BI02F, BI04F and Bll9F, Fusarium strain 8501F and Trichoderma strain K602F and K561F. The optimum pH and temperature forB I 0 IF and B l 002F to degrade crude oil were 5.0 and 28 •c respectively. When complex nutrient such as maize bran was used as nitrogen source with crude oil in minimal salt liquid medium (MSLM) omitting NaN03, the optimum growth reached on 14tl' day of fermentation for both the isolates. BIOIF and BI002F were capable of using crude oil as both carbon and energy source in minimal salt medium. In view of their ability to utilize crude oil as carbon and nitrogen source, these organisms may be used in mitigating the pollution arising out of oil spills in the environmen

Evolution of the flow field in decaying active regions II. Converging flows at the periphery of naked spots

Context. In a previous work, we investigated the evolution of the flow field around sunspots during sunspot decay and compared it with the flow field of supergranular cells. The decay of a sunspot proceeds as it interacts with its surroundings. This is manifested by the changes observed in the flow field surrounding the decaying spot. Aims. We now investigate in detail the evolution of the flow field in the direct periphery of the sunspots of the same sample and aim to provide a complete picture of the role of large-scale flows present in sunspot cells. Methods. We analyse the horizontal velocity profiles of sunspots obtained from observations by the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO). We follow their evolution across the solar disc from their stable phase to their decay and their final disappearance. Results.We find two different scenarios for the evolution of the flow region surrounding a spot in the final stage of its decay: (i) either the flow cell implodes and disappears under the action of the surrounding supergranules or (ii) it outlives the spot. In the later case, an inwards flow towards the remaining naked spot develops in the vicinity closest to the spot followed by an outflow further out. These findings provide observational evidence to theoretical predictions by realistic magnetohydrodynamic (MHD) sunspot and moat region simulations. Conclusions. The Evershed flow and the moat flow, both connected to the presence of fully fledged sunspots in a spot cell, vanish when penumbrae decay. Moat flows decline into supergranular flows. The final fate of a spot cell depends on its interaction with the surrounding supergranular cells. In the case of non-imploding spot cells, the remaining naked spot develops a converging inflow driven by radiative cooling and a geometrical alignment of granules in its periphery which is similar to that observed in pores

Acoustic Events in the Solar Atmosphere from Hinode/SOT NFI observations

We investigate the properties of acoustic events (AEs), defined as spatially concentrated and short duration energy flux, in the quiet sun using observations of a 2D field of view (FOV) with high spatial and temporal resolution provided by the Solar Optical Telescope (SOT) onboard \textit{Hinode}. Line profiles of Fe \textsc{i} 557.6 nm were recorded by the Narrow band Filter Imager (NFI) on a $82" \times 82"$ FOV during 75 min with a time step of 28.75 s and 0.08$"$ pixel size. Vertical velocities were computed at three atmospheric levels (80, 130 and 180 km) using the bisector technique allowing the determination of energy flux in the range 3-10 mHz using two complementary methods (Hilbert transform and Fourier power spectra). Horizontal velocities were computed using local correlation tracking (LCT) of continuum intensities providing divergences. The net energy flux is upward. In the range 3-10 mHz, a full FOV space and time averaged flux of 2700 W m$^{-2}$ (lower layer 80-130 km) and 2000 W m$^{-2}$ (upper layer 130-180 km) is concentrated in less than 1% of the solar surface in the form of narrow (0.3$"$) AE. Their total duration (including rise and decay) is of the order of $10^{3}$ s. Inside each AE, the mean flux is $1.6 10^{5}$ W m$^{-2}$ (lower layer) and $1.2 10^{5}$ W m$^{-2}$ (upper). Each event carries an average energy (flux integrated over space and time) of $2.5 10^{19}$ J (lower layer) to $1.9 10^{19}$ J (upper). More than $10^{6}$ events could exist permanently on the Sun, with a birth and decay rate of 3500 s$^{-1}$. Most events occur in intergranular lanes, downward velocity regions, and areas of converging motions.Comment: 18 pages, 10 figure

Prediction of Natural Gas Compressibility Factor in a Single-Phase Gas Reservoir: A Comparative Study

Natural gas compressibility factor plays important roles in pipeline design, reserve estimation and gas metering. The aim of this study is to presents the most accurate and reliable method of computing gas compressibility factor in a single-phase gas reservoir at various reservoir pressures. In this study, the gas compositions and the specific gravity of the respective gas compounds were retrieved from literatures. This specific gravity determine the pseudo critical and the pseudo reduced properties (temperature and pressure) of the respective gas compounds being studied. The predicted methods studied are Papay correlation, Hall-Yarborough equation of state (EOS), viral EOS, Beggs and Brill and Dranchuk-Abu-Kassem correlation. The methods are expressed as functions of the pseudo-reduced temperature and pressure, thereby predicting the compressibility factor of the predicted methods. The accuracy and the performance of the methods were tested by comparing the results obtained from the methods studied with experimental z-factor values obtained from the literatures. The experimental z-factor values were set as standard for the predicted methods studied. Six (6) statistical parameters and various charts (line and column charts) were used to attest the effectiveness and the precision of the methods. The statistical tools are average absolute error (AAE), average absolute relative error (AARE), root mean square error (RMSE), residual sum of square (RSS), mean square error (MSE) and coefficient of determination (R2). The results of the study shows that, the Papay correlation has the highest coefficient of regression, R2= 92%, rated as the most accurate, reliable and best method. The Hall-Yarborough equation of state has R2 of 86%. The Viral equation of state has R2 of 83%. The Beggs and Brill correlation has R2 of 42%. The Dranchuk-Abu-Kassem correlation has R2 of 10.5%. The Beggs and Brills correlation method is not suitable for application, if the pseudo-reduced pressure is less than 0.92. The Dranchuk-Abu-Kassem correlation is only applicable, if the pseudo-reduced properties are within the range of 0.2<Ppr<15, 1.0<Tpr<3.0. The Hall-Yarborough equation of state cannot be used if the pseudo-reduced temperature is less than one