• Title/Summary/Keyword: hazard levels

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Efficient damage assessment for selected earthquake records based on spectral matching

  • Strukar, Kristina;Sipos, Tanja Kalman;Jelec, Mario;Hadzima-Nyarko, Marijana
    • Earthquakes and Structures
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    • v.17 no.3
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    • pp.271-282
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    • 2019
  • Knowing the response of buildings to earthquakes is very important in order to ensure that a structure is able to withstand a given level of ground shaking. Thus, nonlinear dynamic earthquake engineering analyses are unavoidable and are preferable procedure in the seismic assessment of buildings. In order to estimate seismic performance on the basis of the hazard at the site where the structure is located, the selection of appropriate seismic input is known to be a critical step while performing this kind of analysis. In this paper, seismic analysis is performed for a four-story reinforced concrete ISPRA frame structure which is designed according to Eurocode 8 (EC8). A total of 90 different earthquake scenarios were selected, 30 for each of three target spectrums, EC8 spectrum, Uniform Hazard Spectrum (UHS), and Conditional Mean Spectrum (CMS). The aim of this analysis was to evaluate the average maximum Inter-story Drift Ratio (IDR) for each target spectrum. Time history analysis for every earthquake record was obtained and, as a result, IDR as the main measure of damage were presented in order to compare with defined performance levels of reinforced concrete bare frames.

Characteristics Associated with Survival in Patients Receiving Continuous Deep Sedation in a Hospice Care Unit

  • Ahn, Hee Kyung;Ahn, Hong Yup;Park, So Jung;Hwang, In Cheol
    • Journal of Hospice and Palliative Care
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    • v.24 no.4
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    • pp.254-260
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    • 2021
  • Continuous deep sedation (CDS) is an extreme form of palliative sedation to relieve refractory symptoms at the end of life. In this study, we shared our experiences with CDS and examined the clinical characteristics associated with survival in patients with terminal cancer who received CDS. We conducted a chart audit of 106 consecutive patients with terminal cancer who received CDS at a single hospice care unit between January 2014 and December 2016. Survival was defined as the first day of admission to the date of death. The associations between clinical characteristics and survival were presented as hazard ratios and 95% confidence intervals using a Cox proportional hazard model. The mean age of participants was 65.2 years, and 33.0% (n=35) were women. Diazepam was the most commonly administered drug, and haloperidol or lorazepam were also used if needed. One sedative was enough for a majority of the patients. Stepwise multivariate analysis identified poor functioning, a high Palliative Prognostic Index score, hyperbilirubinemia, high serum ferritin levels, and a low number of sedatives as independent poor prognostic factors. Our experiences and findings are expected to be helpful for shared decision-making and further research on palliative sedation.

Seismic performance-based optimal design approach for structures equipped with SATMDs

  • Mohebbi, Mohtasham;Bakhshinezhad, Sina
    • Earthquakes and Structures
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    • v.22 no.1
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    • pp.95-107
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    • 2022
  • This paper introduces a novel, rigorous, and efficient probabilistic methodology for the performance-based optimal design (PBOD) of semi-active tuned mass damper (SATMD) for seismically excited nonlinear structures. The proposed methodology is consistent with the modern performance-based earthquake engineering framework and aims to design reliable control systems. To this end, an optimization problem has been defined which considers the parameters of control systems as design variables and minimization of the probability of exceeding a targeted structural performance level during the lifetime as an objective function with a constraint on the failure probability of stroke length damage state associated with mass damper mechanism. The effectiveness of the proposed methodology is illustrated through a numerical example of performance analysis of an eight-story nonlinear shear building frame with hysteretic bilinear behavior. The SATMD with variable stiffness and damping have been designed separately with different mass ratios. Their performance has been compared with that of uncontrolled structure and the structure controlled with passive TMD in terms of probabilistic demand curves, response hazard curves, fragility curves, and exceedance probability of performance levels during the lifetime. Numerical results show the effectiveness, simplicity, and reliability of the proposed PBOD method in designing SATMD with variable stiffness and damping for the nonlinear frames where they have reduced the exceedance probability of the structure up to 49% and 44%, respectively.

Direct displacement-based seismic design methodology for the hybrid system of BRBFE and self-centering frame

  • Akbar Nikzad;Alireza Kiani;Seyed Alireza Kazerounian
    • Structural Engineering and Mechanics
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    • v.88 no.5
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    • pp.463-480
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    • 2023
  • The buckling-restrained braced frames with eccentric configurations (BRBF-Es) exhibit stable cyclic behavior and possess a high energy absorption capacity. Additionally, they offer architectural advantages for incorporating openings, much like Eccentrically Braced Frames (EBFs). However, studies have indicated that significant residual drifts occur in this system when subjected to earthquakes at the Maximum Considered Earthquake (MCE) hazard level. Consequently, in order to mitigate these residual drifts, it is recommended to employ self-centering systems alongside the BRBF-E system. In our current research, we propose the utilization of the Direct Displacement-Based Seismic Design method to determine the design base shear for a hybrid system that combines BRBF with an eccentric configuration and a self-centering frame. Furthermore, we present a methodology for designing the individual components of this composite system. To assess the effectiveness of this design approach, we designed 3-, 6-, and 9-story buildings equipped with the BRBF-E-SCF system and developed finite element models. These models were subjected to two sets of ground motions representing the Maximum Considered Earthquake (MCE) and Design Basis Earthquake (DBE) seismic hazard levels. The results of our study reveal that although the combined system requires a higher amount of steel material compared to the BRBF-E system, it substantially reduces residual drift. Furthermore, the combined system demonstrates satisfactory performance in terms of story drift and ductility demand.

Impact of anthropogenic activities on the accumulation of heavy metals in water, sediments and some commercially important fish of the Padma River, Bangladesh

  • M Golam Mortuza
    • Fisheries and Aquatic Sciences
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    • v.27 no.2
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    • pp.66-75
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    • 2024
  • Heavy metals are naturally found in the ecosystem, and their presence in the freshwater river is increasing through anthropogenic activities which pose a threat to living beings. In this study, heavy metal concentrations (Zn, Mn, Cu, Cd, Cu, Cr, Pb, and Ni) in different organs (muscle, skin, and gill) of fish from the Padma River were evaluated to quantify, and compare the contamination levels and related human health risks. The results revealed that the heavy metal concentrations in the water, surface sediments, and fish taken from the Padma River were far below the WHO/USEPA's permitted limits. The estimated daily intake (EDI) value in muscle was less than the tolerable daily intake (TDI). The target hazard quotient (THQ) and hazard indexes (HI) were less than 1, showing that consumers face no non-carcinogenic risk (CR). CR values of Cu, Cd, Cr, Pb, and Ni ranged from 4.00 × 10-8 to 6.35 × 10-6, less than 10-4, and total carcinogenic risk (CRt) values ranged from 9.85 × 10-6 to 1.10 × 10-5, indicating some pose a CR from consumption of those fish from the Padma River. To establish a more accurate risk assessment, numerous exposure routes, including inhalation and cutaneous exposure, should be explored.

A Study on Microbiological Hazard Analysis according to the Steaming Process of Various Rice Cakes

  • Kim, Jung-Yun;Park, Da-Hyun;Rha, Young-Ah
    • Culinary science and hospitality research
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    • v.23 no.6
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    • pp.20-26
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    • 2017
  • To guarantee the safety of rice cake production, the Hazard Analysis Critical Control Points system was applied to the production process. The purpose of this study was to analyze the microbiological hazards of the manufacture of rice cakes, and establish critical limits in the process of the manufacturing rice cakes. To control the microbiological hazards, the sterilization process was set to a critical limit. The process of manufacturing rice cakes can reduce these microbiological hazards during the steaming process. A microorganism test for each specimen was conducted three times and compared with before and after steaming processes. The finished product was conducted by microbiology experiment and the validity of the steaming process was verified. The results were determined to be capable of reducing the biological element of Critical Control Point via the steaming process. Microbiology such as aerobic plate count, coliform, Escherichia coli(E. coli), Listeria monocytogenes, Enterohemorrhagic E. coli, Salmonella spp., Bacillus cereus, Staphylococcus aureus and Clostridium perfringens was evaluated by the experimental method of Korean Food Standards Codex. Aerobic plate count was reduced by steaming process, and no microorganism were detected. All rice cakes in the finished product were judged to be safe for both the Escherichia coli and general bacteria. In conclusion, it suggested that a HACCP plan was necessary for management standard and systematic approach in the establishment of critical limit, problem resolution, verification method, education, and records management. Based on this study, it is intended to provide a baseline for improving quality control standards and improving hygiene levels for small manufacturers.

Effects of High Dose Irradiation on The Leukocyte Life Span (고선양(高線量) 방사선(放射線)이 백혈구(白血球) 수명(壽命)에 미치는 영향(影響))

  • Koh, Joo-Hwan;Chong, In-Yong;Kim, Yong-Kyu
    • Journal of Radiation Protection and Research
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    • v.9 no.2
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    • pp.67-75
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    • 1984
  • As a part of studies on acute effects of high dose irradiation the present report was carried out to evaluate the changes of the leukocyte life span in the Newzealand white male rabbits by a single whole body exposure to gamma rays from $^{60}Co$ teleirradiation unit. The exposure was done in dose levels of 100, 300, 550 and 1,000 rad to each experimental group of 10 rabbits. The life span and apparent half survival time of leukocytes, and the elution rate of leukocytes in the circulating blood were measured by McMillan method using $^{51}Cr$. 1. As a critical indicator of radiation hazards of the Newzealand male rabbits, the LD 50/30 and LD 100/30 after whole body exposure was estimated as 550 and 1,000 rads respectively. 2. The life span of leukocyte in the circulation after irradiation was slightly shortened in the 100 rad irradiated group, as compared with the unirradiated control group, but markedly shortened in the 300, 550 and 1,000 rads irradiated group. 3. After irradiation, decrease of leukocyte half survival time in the circulation showed the same pattern as that of leukocytes life span. 4. As the irradiation doses increased, the elution rate of $^{51}Cr$ loss from $^{51}Cr$ tagged leukocytes in the circulation were markedly increased gradually. 5. The life span shortening of leukocytes in the circulation after irradiation seems to occure by two processes of senescence acceleration and early destruction.

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Safety analysis to derive safety requirement in the railway system

  • Joung, Eui-Jin;Shin, Kyung-Ho;Kim, Yong-Gyu
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.1
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    • pp.383-386
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    • 2006
  • The safety of the railway system is important because the system is a mass transit system and the results of the accident are inconceivable. The railway system is operated by train operation system such as train control system. So the train control system requires safety critical characteristics. In the European railway, ETCS (European Train Control System) project has been finished to accomplish the interoperability of each national railway signaling system. According to the interoperability degree, ETCS levels are suggested. As the highest level, ETCS level 3 suggests a radio communication. Also recently urban railway system is operated by driverless and automatic train control system. In this circumstance, more safety is required than before in the railway system. In order to accomplish the safety of a system, the requirements considering safety have to be suggested. The requirement is a set of several functions such as general function, environment, safety etc. For the safety critical system, safety function is more important than any other functions. The safety functions are deduced by safety analysis. In order to perform the safety analysis, the system hazards have to be identified and then risk analysis for each hazard should be performed. The risk is related to the frequency and the severity of each hazard. And then countermeasures for each risk have to be prepared. The summary of the countermeasures is about a kind of safety functions in a system. In this paper, the safety functions for a train control system are presented according to the above procedure.

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Assessment of Radiological Hazards in Some Foods Products Consumed by the Malian Population Using Gamma Spectrometry

  • Adama Coulibaly;David O. Kpeglo;Emmanuel O. Darko
    • Journal of Radiation Protection and Research
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    • v.48 no.2
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    • pp.84-89
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    • 2023
  • Background: Food consumption is one of the most important routes for radionuclide intake for the public; therefore, there is the need to have a comprehensive understanding of the amount of radioactivity in food products. Consumption of radionuclide-contaminated food could increase potential health risks associated with exposure to radiation such as cancers. The present study aims to determine radioactivity levels in some food products (milk, rice, sugar, and wheat flour) consumed in Mali and to evaluate the radiological effect on the public health from these radionuclides. Materials and Methods: The health impact due to ingestion of radionuclides from these foods was evaluated by the determination of activity concentration of radionuclides 238U, 232Th, 40K, and 137Cs using gamma spectrometry system with high-purity germanium detector and radiological hazards index in 16 samples collected in some markets, mall, and shops of Bamako-Mali. Results and Discussion: The average activity concentrations were 9.8±0.6 Bq/kg for 238U, 8.7±0.5 Bq/kg for 232Th, 162.9±7.9 Bq/kg for 40K, and 0.0035±0.0005 Bq/kg for 137Cs. The mean values of radiological hazard parameters such as annual committed effective dose, internal hazard index, and risk assessment from this work were within the dose criteria limits given by international organizations (International Commission on Radiological Protection and United Nations Scientific Committee on the Effects of Atomic Radiation) and national standards. Conclusion: The results show low public exposure to radioactivity and associated radiological impact on public health. Nevertheless, this study stipulates vital data for future research and regulatory authorities in Mali.

Analysis of ethyl carbamate in alcoholic beverages (주류 중 에틸카바메이트 분석)

  • Park, Sung-Kug;Yoon, Taehyung;Choi, Dongmi
    • Analytical Science and Technology
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    • v.21 no.1
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    • pp.53-57
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    • 2008
  • In order to survey the contents of ethyl carbamate in alcoholic beverages, GC/MS-SIM method was used after extraction with dichloromethane in solid phase extract cartridge contained alcoholic beverages. In the applied GC/MS-SIM method, the values of recoveries and relative standard deviation were ranged from 85.2 % to 87.9 % and from 0.7 % to 1.9 %, the limit of detection and quantification were $2{\mu}g/kg$ and $10{\mu}g/kg$. Depending on alcoholic beverage kinds, the levels were variable and the average level was $194{\mu}g/kg$ for liquor, $105{\mu}g/kg$ for fruit wine, $62{\mu}g/kg$ distilled spirit, $28{\mu}g/kg$ for sake, $15{\mu}g/kg$ for yakju, $12{\mu}g/kg$ for other alcohol beverages, ND for soju, respectively.