FMEA and Fault Tree based Software Safety Analysis of a Railroad Crossing Critical System

Software for safety-critical systems must deal with the hazards identified by safety analysis in order to make the system safe, risk-free and fail-safe. Certain faults in critical systems can result in catastrophic consequences such as death, injury or environmental harm. The focus of this paper is an approach to software safety analysis based on a combination of two existing fault removal techniques. A comprehensive software safety analysis involving a combination of Failure Modes and Effects Analysis (FMEA) and Fault Tree Analysis (FTA) is conducted on the software functions of the critical system to identify potentially hazardous software faults. A prototype safety-critical system - Railroad Crossing Control System (RCCS), incorporating a microcontroller and software to operate the train on a track circuit is described

Ti:sapphire-pumped deep-infrared femtosecond optical parametric oscillator based on CdSiP2

We report on a femtosecond optical parametric oscillator (OPO) for the deep-infrared (deep-IR) based on the Kerr-lens-mode-locked Ti:sapphire laser as the pump source. By deploying a novel cascaded intracavity arrangement, comprising a femtosecond OPO based on the nonlinear crystal, CdSiP2CdSiP2, synchronously pumped internal to a MgO:PPLN femtosecond OPO, we have generated broadly tunable radiation across 5958–8117 nm using rapid static cavity delay tuning, with a maximum power of 64 μW at 6791 nm, limited by the absorption in mirror substrates as well as polarization-dependent intracavity losses. The deep-IR idler power exhibits excellent passive stability of better than 1.1% rms over 2 h, with a spectral bandwidth as large as ∼650  nm∼650  nm at ∼6800  nm∼6800  nm. The demonstrated concept is generic and can be similarly deployed in other operating time scales and wavelength regions, also using different laser pump sources and nonlinear materials.Peer ReviewedPostprint (author's final draft

Epifil: a dynamic model of infection and disease in lymphatic filariasis

The lack of a quantitative framework that describes the dynamic relationships between infection and morbidity has constrained efforts aimed at the community-level control of lymphatic filariasis. In this paper, we describe the development and validation of EPIFIL, a dynamic model of filariasis infection intensity and chronic disease. Infection dynamics are modeled using the well established immigration-death formulation, incorporating the acquisition of immunity to infective larvae over time. The dynamics of disease (lymphodema and hydrocele) are modeled as a catalytic function of a variety of factors, including worm load and the impact of immunopathological responses. The model was parameterized using age-stratified data collected from a Bancroftian filariasis endemic area in Pondicherry in southern India. The fitted parameters suggest that a relatively simple model including only acquired immunity to infection and irreversible progression to disease can satisfactorily explain the observed infection and disease patterns. Disease progression is assumed to be a consequence of worm induced damage and to occur at a high rate for hydrocele and a low rate for lymphodema. This suggests that immunopathology involvement may not be a necessary component of observed age-disease profiles. These findings support a central role for worm burden in the initiation and progression of chronic filarial disease

Evaluation of sorghum genotypes for the stay-green trait and grain yield

Sorghum (Sorghum bicolor) is one of the major cereal crops in the semi-arid tropics where prolonged droughts are frequent. Water deficit is the major constraint to rainfed sorghum production worldwide. In India sorghum is primarily cultivated in two distinct seasons: June to October (rainy/kharif) and October to February (postrainy/rabi). The postrainy season crop is grown mostly on stored soil moisture on Vertisols over 5 million ha of the Deccan Plateau situated between 16° and 20° N and 74° and 80° E. Sorghum grain yields are increasing during the rainy season but have remained the same in postrainy season (Vidyabhushanam 1986). In postrainy season sorghum, fodder quality may suffer due to senescence as the crop is grown on residual moisture and often experiences severe terminal drought stress. Staygreen or non-senescence is an important trait associated with drought tolerance (Rosenow 1977). It is indicated by maintenance of green stems and upper leaves when water is limiting during grain filling. Sorghum genotypes with the stay-green trait continue to fill their grains normally even under limited water or moisture stress conditions (Duncan et al. 1981, Rosenow and Clark 1981, Borrell et al. 2000). Delaying the onset of leaf senescence and reducing its rate (ie, two components of the stay-green trait) offer an effective strategy for increasing grain production, fodder quality and grain crop residues particularly under water limited conditions. This article describes the effect of the stay-green trait on grain yield of 38 sorghum stay-green genotypes

Improved sorghum hybrids with grain mold resistance

Sorghum (Sorghum bicolor) is the fifth most important cereal crop globally after wheat (Triticum aestivum), rice (Oryza sativa), maize (Zea mays) and barley (Hordeum vulgare) with multiple uses as food, feed, fodder and fuel. It has a great potential in the gluten-free food market. Globally it is grown on over 43 million ha predominantly in tropical Africa and India. It is also grown in temperate areas (Americas, Europe and Australia) as a feed crop. In the tropics, sorghum is faced with a hostile environment, where unreliable rainfall, poor soils, pests, diseases and parasitic weeds constantly exert harsh selection pressure. India has the largest area (8.5 million ha) under sorghum and 45% of this area is in rainy season while postrainy season sorghum accounts for the remaining area

Selection of restorers and varieties for stalk sugar traits in sorghum

In India, sorghum (Sorghum bicolor) is an important staple food crop for a large population and ranks fifth in area and production next to rice (Oryza sativa), wheat (Triticum aestivum), maize (Zea mays) and barley (Hordeum vulgare). Sorghums that have 10–25% sugar in stalk juice at grain maturity are called sweet sorghums (Harlan and deWet 1972). Sweet sorghums are characterized by their wider adaptability, rapid growth and sugar accumulation associated with high biomass in the semi-arid tropics (Smith et al. 1987). The sugars presented in the stalk juice of sweet sorghum can be fermented and converted to ethanol using relatively simple techniques (Smith and Reeves 1981, Hill et al. 1987, Smith et al. 1987). Sorghum stalks are ideal for ethanol production as the ethanol is significantly cleaner (low sulfur), and potable alcohol produced from sorghum grains has superior quality. The feasibility of converting stalk sugars to ethanol/syrup/jaggery on or near farms, and the adaptability of sorghum to a wide range of environments prompted researchers to evaluate the potential of sweet sorghum as an alternative crop for ethanol production (Daniel et al. 1991)

Variation in the quality parameters of sweet sorghum across different dates of sowing

Sweet sorghum (Sorghum bicolor) is a multipurpose crop (food, feed, fodder and fuel) that has potential as an alternative raw material for ethanol production owing to its high biomass production, high Brix (%), short duration and low water requirement (4,000 cubic m ha-1) and wider adaptability (Reddy et al. 2005). In addition, sweet sorghum is a seed propagated species and better suited for mechanized crop production. The other significant advantage is that the sweet sorghum ethanol blended gasohol is environment friendly. It does not have sulfur and aldehydes making it a green fuel

Development of male-sterile lines in sorghum

Sorghum [Sorghum bicolor (L.) Moench] is the fi fth important cereal crop in the world after wheat, rice, maize and barley. Of late, it has emerged as ‘fuel’ crop in addition to its food, feed and fodder utilities. Sorghum is predominantly a selfpollinated crop and development of new ‘varieties’ is a natural option for crop improvement. However, there is 5 to 15% outcrossing in sorghum depending upon the wind direction, nature of genotype, and humidity (House 1985), which makes it amenable for use in population improvement and hybrid development to exploit the heterosis. Discovery of genetic male sterility (GMS) and cytoplasmic-nuclear male sterility (CMS) facilitated the application of recurrent selection procedures and hybrid cultivar development methods, respectively, in sorghum improvement. In this article, male-sterile line development using CMS in sorghum is described

Transition metal saccharide chemistry and biology: syntheses, characterization, solution stability and putative bio-relevant studies of iron-saccharide complexes

A number of Fe(III) complexes of saccharides and their derivatives, and those of ascorbic acid were synthesized, and characterized by a variety of analytical, spectral (FT-IR, UV-Vis, EPR, Mossbauer and EXAFS), magnetic and electrochemical techniques. Results obtained from various methods have shown good correlations. Data obtained from EPR, magnetic susceptibility and EXAFS techniques could be fitted well with the mono-, di- and trinuclear nature of the complexes. The solution stability of these complexes has been established using UV-Vis absorption and cyclic voltammetric techniques as a function of pH of the solution. Mixed valent, Fe(II,III) ascorbate complexes have also been synthesized and characterized. Reductive release of Fe(II) from the complexes using sodium dithionite has been addressed. In vitro absorption of Fe(III)-glucose complex has been studied using everted sacs of rat intestines and the results have been compared with that of simple ferric chloride. Fe(III)-saccharide complexes have shown regular protein synthesis even in hemin-deficient rabbit reticulocyte lysate indicating that these complexes play a role that is equivalent to that played by hemin in order to restore the normal synthesis of protein. These complexes have exhibited enhanced DNA cleavage properties in the presence of hydrogen peroxide with pUC-18 DNA plasmid