Evolving Threshold of Flood-Leading Precipitation in a User-Oriented Forecast System Based on the TIGGE Dataset

Specific users play a key role in interactive forecast systems through user-oriented information (UOI). For hydrological users, a key component of the user-oriented forecast system (UOFS) is to determine the threshold of flood-leading precipitation (TFLP) as a target of the forecast by considering the decision-making information at the user end. This study demonstrates a novel way of simulating TFLP via the inverse simulation of a hydrological model, combined with the flood hazard assessment in the upper reaches of the Huai River Basin controlled by the Wang Jiaba (WJB) hydrological station. The flood hazard, defined as the probability of precipitation beyond the daily evolving TFLP for the next day, was evaluated by using the THORPEX Interactive Global Grand Ensemble (TIGGE) datasets, including 162 members retrieved from 5 TIGGE archive centers. Having integrated the real-time monitored water level (as the UOI) into the UOFS, we applied it to the flood season of 2008 as a case study to evaluate the flood hazard generated by the UOFS for the WJB sub-basin. The simulated TFLP corresponded well with the gap between the monitored and warning water level. The predicted flood hazard probability showed good agreement with the first two flood peaks at 100% accuracy, while exceeding 60% accuracy for the third flood event in that season. Thus, the flood hazard could be better quantified via integration of the forecasted flood-leading precipitation. Overall, this study highlights the usefulness of a UOFS coupled with interactive UOI of real-time water level to determine the dynamical TFLP for flood hazard evaluation with ensemble precipitation forecast. The early flood warning which resulted from such integrated UOFS is directly applicable to operational flood prevention and mitigation.

Radiation dose risk variability and its implication in industrial and mining regions, NW Nigeria

The study area located in the southern part of Kebbi State, northwestern Nigeria, has witnessed intense mining activities and upscale industrialization in recent years. These events have necessitated deeper and insightful studies into radiological hazard evaluation to mitigate associated adverse consequences and enforce protective measures in the environment. A total of 45 sampled locations each were taken for both industrial and mining sites in northwestern Nigeria to determine the concentration of Potassium-40, Thorium-232 and Uranium-238 radionuclides as applied to radiological hazard analysis. The mean value of the absorbed dose in the industrial site was 90 nGy/h, whereas the mining site recorded a mean value of 210 nGy/h. Other radiological indices such as radium equivalent factor, external risk assessment, internal index and representative gamma index recorded mean values of 187.68, 0.507, 0.547 and 0.768 respectively, whereas the same hazard indices presented higher values of 412.58, 1.114, 1.231 and 1.675 respectively in the mining site. The variability studies showed that the dose risk ratio of the industrial region to the mining region is 1:2. The mining site presented radiological hazard indices higher than the recommended global threshold hence should be classified as a restricted zone to forestall health-related crises which may manifest among local dwellers.

Managing Safety and Ensuring Asset Integrity Through Judicious PFP Application

Passive fire protection (PFP) is applied to steel structures in process plants to delay temperature rise and maintain structural integrity until active firefighting methods are deployed and fire is contained. Our largest gas plant was developed in several phases spanning over 25years with fireproofing designed and applied as per existing philosophy during respective execution phases. During recent Risk Management Survey, potential gaps in fireproofing were observed and survey recommended a campaign to review and identify similar gaps across entire Plant. This paper highlights the approach for gap identification, assessment and optimal recommendations which ensure safety and asset integrity while avoiding high OPEX. Fire hazard evaluation is carried out based on risk assessment of fire and hydrocarbon leakage scenarios in process plant, and recommendations for fire prevention, protection and firefighting measures are provided. Requirement of fire protection is dependent on fire source and resulting fire influence zone (fireproofing zone drawings, FPZ). Structures which are located within the FPZ are then evaluated as per identified criteria in a sequential approach (e.g. whether sudden collapse will cause significant damage, structure supports equipment containing toxic material etc.). Further detailed assessment of structural members and their impact on overall structural stability and integrity is carried out for identified structures to determine fireproofing needs. Based on the outcome, fireproofing is applied for identified members. The scope involved assessment of structural steel fireproofing in the entire complex comprising of over 40 numbers process units and 12 numbers utility units. Several teams conducted physical site survey to identify the actual fireproofing based on zone drawings across the entire plant. Desktop assessment and identification of gaps were carried out primarily based on Project fireproofing specifications, fireproofing zone drawings, fireproofing location drawings, fireproofing schedule, structural design calculations and 3-D models wherever available for respective areas. Study revealed that actual fireproofing at site in each phase of plant is consistent within all process units installed as part of that particular project, however inconsistencies were observed when compared across the different phases, probably due to different interpretation of requirements. To ensure consistency a common criteria was established considering fire source, equipment supported by structure, criticality of member and industry standards. Optimized solutions was recommended to avoid high OPEX while ensuring asset integrity and safety. Fireproofing criteria are general guidelines susceptible to various interpretations by respective users. Establishment of common criteria and elimination of ambiguities in specifications enables consistent application of fireproofing, resulting in optimization while ensuring asset safety and integrity. The approach adopted by ADNOC Gas Processing can be shared with other group companies to enable each organization be prepared to justify the actions in case of any external / internal audits.

Thermal hazard evaluation on spontaneous combustion characteristics of nitrocellulose solution under different atmospheric conditions

Nitrocellulose (NC) is widely used in both military and civilian fields. Because of its high chemical sensitivity and low decomposition temperature, NC is prone to spontaneous combustion. Due to the dangerous properties of NC, it is often dissolved in other organic solvents, then stored and transported in the form of a solution. Therefore, this paper took NC solutions (NC-S) with different concentrations as research objects. Under different atmospheric conditions, a series of thermal analysis experiments and different reaction kinetic methods investigated the influence of solution concentration and oxygen concentration on NC-S’s thermal stability. The variation rules of NC-S’s thermodynamic parameters with solution and oxygen concentrations were explored. On this basis, the spontaneous combustion characteristics of NC-S under actual industrial conditions were summarized to put forward the theoretical guidance for the spontaneous combustion treatment together with the safety in production, transportation, and storage.

Radiological Hazard Evaluation of Some Egyptian Magmatic Rocks Used as Ornamental Stone: Petrography and Natural Radioactivity

Magmatic rocks represent one of the most significant rocks due to their abundance, durability and appearance; they can be used as ornamental stones in the construction of dwellings. The current study is concerned with the detailed petrography and natural radioactivity of seven magmatic rocks. All are commercial granitic rocks and are identified as black Aswan, Nero Aswan, white Halayeb, Karnak, Verdi, red Hurghada and red Aswan. Their respective mineralogical compositions are classified as porpheritic granodiorite, granodiorite, tonalite, monzogranite, syenogranite, monzogranite and syenogranite. A total of nineteen samples were prepared from these seven rock types in order to assess their suitability as ornamental stones. Concentrations of 226Ra, 232Th and 40K radionuclides were measured using NaI (Tl) scintillation gamma-ray spectrometry. Among the studied magmatic rocks, white Halayeb had the lowest average values of 226Ra (15.7 Bq/kg), 232Th (4.71 Bq/kg) and 40K (~292 Bq/kg), all below the UNSCEAR reported average world values or recommended reference limits. In contrast, the other granitic rocks have higher values than the recommended limit. Except for the absorbed dose rate, other radiological hazard parameters including radium equivalent activity, annual effective dose equivalent, external, and internal hazard indices reflect that the White Halyeb rocks are favorable for use as ornamental stone in the construction of luxurious and high-demand residential buildings.

Validating a model of architectural hazard visibility with low-vision observers

Pedestrians with low vision are at risk of injury when hazards, such as steps and posts, have low visibility. This study aims at validating the software implementation of a computational model that estimates hazard visibility. The model takes as input a photorealistic 3D rendering of an architectural space, and the acuity and contrast sensitivity of a low-vision observer, and outputs estimates of the visibility of hazards in the space. Our experiments explored whether the model could predict the likelihood of observers correctly identifying hazards. In Experiment 1, we tested fourteen normally sighted subjects with blur goggles that simulated moderate or severe acuity reduction. In Experiment 2, we tested ten low-vision subjects with moderate to severe acuity reduction. Subjects viewed computer-generated images of a walkway containing five possible targets ahead—big step-up, big step-down, small step-up, small step-down, or a flat continuation. Each subject saw these stimuli with variations of lighting and viewpoint in 250 trials and indicated which of the five targets was present. The model generated a score on each trial that estimated the visibility of the target. If the model is valid, the scores should be predictive of how accurately the subjects identified the targets. We used logistic regression to examine the correlation between the scores and the participants’ responses. For twelve of the fourteen normally sighted subjects with artificial acuity reduction and all ten low-vision subjects, there was a significant relationship between the scores and the participant’s probability of correct identification. These experiments provide evidence for the validity of a computational model that predicts the visibility of architectural hazards. It lays the foundation for future validation of this hazard evaluation tool, which may be useful for architects to assess the visibility of hazards in their designs, thereby enhancing the accessibility of spaces for people with low vision.