Towards the Formal Reliability Analysis of Oil and Gas Pipelines

It is customary to assess the reliability of underground oil and gas pipelines in the presence of excessive loading and corrosion effects to ensure a leak-free transport of hazardous materials. The main idea behind this reliability analysis is to model the given pipeline system as a Reliability Block Diagram (RBD) of segments such that the reliability of an individual pipeline segment can be represented by a random variable. Traditionally, computer simulation is used to perform this reliability analysis but it provides approximate results and requires an enormous amount of CPU time for attaining reasonable estimates. Due to its approximate nature, simulation is not very suitable for analyzing safety-critical systems like oil and gas pipelines, where even minor analysis flaws may result in catastrophic consequences. As an accurate alternative, we propose to use a higher-order-logic theorem prover (HOL) for the reliability analysis of pipelines. As a first step towards this idea, this paper provides a higher-order-logic formalization of reliability and the series RBD using the HOL theorem prover. For illustration, we present the formal analysis of a simple pipeline that can be modeled as a series RBD of segments with exponentially distributed failure times.Comment: 15 page

Hypocenter Distribution of Low Frequency Event at Papandayan Volcano

Papandayan volcano is a stratovolcano with irregular cone-shaped has eight craters around the peak. The most active crater in Papandayan is a Mas crater. Distribution of relocated event calculated using Geiger Adaptive Damping Algorithm (GAD) shows that the epicenter of the event centered below Mas crater with maximum rms 0.114. While depth of the hypocenter range between 0-2 km and 5-6 km due to activity of steam and gas

Analisis Kinerja Keuangan Bank Umum Pemerintah Tahun 2013 -2017

The purpose of this study was to determine the effect of CAR, LDR, NIM and BOPO on ROA of Government Commercial Banks listed on the Indonesia Stock Exchange in the Blue Chip category for 2013-2017. The research design used in the preparation of this research is quantitative with descriptive explanations. The analysis method used is multiple linear regression analysis with a sample of 20 company data for the 2013-2017 period and the type of data used is time series. The results of the analysis show that CAR has a significant negative effect on ROA with a regression coefficient of -0.090. LDR has a positive but not significant effect on ROA with a regression coefficient of 0.076. NIM has a positive and significant effect on ROA with a regression coefficient of 0.487. BOPO has a negative and significant effect on ROA with a regression coefficient of -0.565. While the test results simultaneously show CAR, LDR, NIM and BOPO together have a significant effect on ROA with a coefficient of determination of 0.98

A Model for Static and Dynamic Phenomena in Deposition Processes

We have developed a model for friction in a dry granular material,that allows multiple reversible transitions between stick and slipcontacts. The ultimate purpose of the model is to simulatedeposition processes. During these processes a pile structure isformed that is repeatedly destabilised by addition of new material.The present model does not yet include rotation. The model is testedfor a few simple systems. Finally we perform more extensive granulardynamics simulations using the model for 2D and 3D systems. In eachsystem, a steady flow of material is dropped onto a rough surface.DOI : http://dx.doi.org/10.22342/jims.13.2.83.173-18

Inelastic X-ray scattering in correlated (Mott) insulators

We calculate the inelastic light scattering from X-rays, which allows the photon to transfer both energy and momentum to the strongly correlated charge excitations. We find that the charge transfer peak and the low energy peak both broaden and disperse through the Brillouin zone similar to what is seen in experiments in materials like Ca_2 Cu O_2 Cl_2.Comment: 5 pages Revtex4, 6 figure

Nucleate pool boiling in the long duration low gravity environment of the Space Shuttle

The results are presented of an experimental study of nucleate pool boiling performed in the low gravity environment of the space shuttle. Photographic observations of pool boiling in Freon 113 were obtained during the 'Tank Pressure Control Experiment,' flown on the Space Transportation System, STS-43 in August 1991. Nucleate boiling data from large (relative to bubble size) flat heating surfaces (0.1046 by 0.0742 m) was obtained at very low heat fluxes (0.22 to 1.19 kW/sq m). The system pressure and the bulk liquid subcooling varied in the range of 40 to 60 kPa and 3 to 5 C respectively. Thirty-eight boiling tests, each of 10-min duration for a given heat flux, were conducted. Measurements included the heater power, heater surface temperature, the liquid temperature and the system pressure as functions of heating time. Video data of the first 2 min of heating was recorded for each test. In some tests the video clearly shows the inception of boiling and the growth and departure of bubbles from the surface during the first 2 min of heating. In the absence of video data, the heater temperature variation during heating shows the inception of boiling and stable nucleate boiling. During the stable nucleate boiling, the wall superheat varied between 2.8 to 3.8 C for heat fluxes in the range of 0.95 to 1.19 kW/sq m. The wall superheat at the inception of boiling varied between 2 to 13 C

Theory of quasiparticle interference in mirror symmetric 2D systems and its application to surface states of topological crystalline insulators

We study symmetry protected features in the quasiparticle interference (QPI) pattern of 2D systems with mirror symmetries and time-reversal symmetry, around a single static point impurity. We show that, in the Fourier transformed local density of states (FT-LDOS), \rho(\bq,\omega), while the position of high intensity peaks generically depends on the geometric features of the iso-energy contour at energy $\omega$, the \emph{absence} of certain peaks is guaranteed by the opposite mirror eigenvalues of the two Bloch states that are (i) on the mirror symmetric lines in the Brillouin zone (BZ) and (ii) separated by scattering vector \bq. We apply the general result to the QPI on the $<{001} >$-surface of topological crystalline insulator Pb$_{1-x}$Sn$_x$Te and predict all vanishing peaks in \rho(\bq,\omega). The model-independent analysis is supported by numerical calculations using an effective four-band model derived from symmetry analysis.Comment: Six-page text plus 2.5-page appendices, three figures and one table. Accepted versio

Super-enhanced optical energy concentration through a subwavelength aperture using a photonic nanojet

pre-printOptical transmission through resonant subwavelength apertures in optically thick metal films have received an explosion of interest for their ability to overcome the diffraction limit of light and concentrate light efficiently into a subwavelength volume. This achievement has attracted the use of subwavelength apertures in numerous applications, i.e. in near-field optical microscopy, fluorescence correlation spectroscopy, nanoscale optical recording, optical lithography, ultra small photodetectors, novel nanoscale light source, and nonlinear optical processes, etc