Protection Criteria Research Articles

A Source-Related Approach for Discussion on Using Radionuclide-Contaminated Materials in Post-accident Rehabilitation

Background: In the process of discussion on the possibility of using radionuclide-contaminated soil and debris generated by radiation disasters, a strategy for the proper management of radiation exposure protection while considering the source of the contaminated materials is necessary.Materials and Methods: The radiological protection criteria that are likely to be applied to the source-related approach based on the International Commission on Radiological Protection recommendations and the International Atomic Energy Agency safety standards are summarized. We proposed five interpretations of radiation protection to contribute to the promotion of discussion on the possibility of using a part of low-level-radionuclide-contaminated soil and debris in the post-accident rehabilitation. Interpretations I to III are based on the idea of “using a reference level to protect the public in post-accident rehabilitation,” whereas IV and V are based on the idea of “using the dose constraint to protect the public in the post-accident rehabilitation when the sources are handled in a planned activity.” The former idea is subdivided into three based on the definition of the source, which is managed by the reference level, and the latter idea is divided into two depending on whether or not additional dose from using contaminated materials is deemed acceptable.Results and Discussion: To confirm the applicability of the five interpretations presented, we suggested the concrete values of protection criteria via two feasible cases. In this case study, we proposed radiation protection by the dose constraint based on the Interpretation IV and chose 1 mSv/yr for the public and 20 mSv/yr for workers dealing with radionuclide-contaminated materials.Conclusion: We concretely and systematically demonstrated how the concept of radiation protection can be applied to the process of discussion on the possibility of using radionuclide-contaminated materials within the framework of an international system of protection. This study’s findings can provide necessary information to discuss the possibility of using radionuclide-contaminated materials as an alternative option for recovery and reconstruction after a radiation disaster from the viewpoint of radiation protection.

Obstruction of biodiversity conservation by minimum patch size criteria.

Minimum patch size criteria for habitat protection reflect the conservation principle that a single large (SL) patch of habitat has higher biodiversity than several small (SS) patches of the same total area (SL>SS). Nonetheless, this principle is often incorrect, and biodiversity conservation requires placing more emphasis on protection of large numbers of small patches (SS>SL). We used a global database reporting the abundances of species across hundreds of patches to assess the SL>SS principle in systems where small patches are much smaller than the typical minimum patch size criteria applied for biodiversity conservation (i.e., ∼85% of patches <100ha). The 76 metacommunities we examined included 4401 species in 1190 patches. From each metacommunity, we resampled species-area accumulation curves to evaluate how biodiversity responded to habitat existing as a few large patches or as many small patches. Counter to the SL>SS principle and consistent with previous syntheses, species richness accumulated more rapidly when adding several small patches (45.2% SS>SL vs. 19.9% SL>SS) to reach the same cumulative area, even for the very small patches in our data set. Responses of taxa to habitat fragmentation differed, which suggests that when a given total area of habitat is to be protected, overall biodiversity conservation will be most effective if that habitat is composed of as many small patches as possible, plus a few large ones. Because minimum patch size criteria often require larger patches than the small patches we examined, our results suggest that such criteria hinder efforts to protect biodiversity.

Non-unit Protection for Asymmetrical DC Line Faults in Bipolar LCC-HVDC Transmission Systems

The faults in high voltage direct current (HVDC) transmission lines cause a sudden rise in DC, resulting in over-stressing of converter valves and transformer windings. DC line faults of longer duration, or permanent nature, will lead to a severe disturbance in the associated AC network as well. Thus, the HVDC line faults must be detected immediately to interrupt the fault current by initiating proper actions of control and protection. This paper implements a new method to detect the asymmetrical (pole-to-ground) faults in the conventional bipolar LCC-HVDC transmission system. The proposed method defines a Fault Indicating Parameter (FIP) based on the transient voltage and current elements of each pole. The transient elements are obtained based on single-end measurements. Single-end or non-unit measurements lead to the development of simple, cost-effective and fast protection criteria. Also, the method is applicable to faults close to the line boundary and of high resistivity. A two-terminal bipolar LCC-HVDC transmission system, based on ±500 kV, 1000 MW and 900 km length, is used to evaluate the performance of the proposed technique in offline mode, using MATLAB/Simulink software. Also, the results are validated using an OPAL-RT real-time simulator under divergent fault conditions. The simulation results prove the robustness, selectiveness and accuracy of the proposed scheme.

Neural network-based pH and coagulation adjustment system in water treatment

This document presents a machine learning model development as a tool to improve chemical dosing procedure in ariari regional aqueduct (ARA). The supervised learning model has been addressed starting from the knowledge of data color, turbidity and pH at the water inlet to the aqueduct and the dosing results of type A aluminum sulfate and calcium oxide (lime) obtained through jar tests. The construction of the automatic learning model had a comprehensive implementation and improvement field through continuous system training, which allowed an optimal dosage of Aluminum Sulfate and Lime to generate an outlet pH less than 7.5 and outlet turbidity less than 8 nephelometric turbidity unit (NTU). Those outlet water parameters meet the ministry of social protection criteria in Colombia. Also, a virtual jar test was created to reduce the time required to obtain chemical dosing values to less than a minute. In contrast, a laboratory test takes approximately a half-hour to displays results.

US and international per- and polyfluoroalkyl substances surface water quality criteria: A review of the status, challenges, and implications for use in chemical management and risk assessment.

Regulation of per- and polyfluorinated substances (PFAS) in surface water is a work-in-progress with relatively few criteria promulgated in the United States and internationally. Surface water quality criteria (SWQC) or screening values derived for perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) by Australia, Canada, the European Union (EU), and four US states (Florida, Michigan, Minnesota, and Wisconsin), and the San Francisco Bay Regional Water Quality Control Board (SFB RWQCB; California) were compared. Across these eight jurisdictions, promulgated numeric criteria for the same compound and receptor span over five orders of magnitude as a result of different approaches and data interpretations. Human health criteria for PFOS range from 0.0047 to 600 ng/L depending on route of exposure (e.g., fish consumption or drinking water) and are lower than most ecological criteria for protection of aquatic and wildlife receptors. Data gaps and uncertainty in chronic toxicity and bioaccumulation of PFOS and PFOA, as well as the use of conservative assumptions regarding intake and exposure, have resulted in some criteria falling at or below ambient background concentrations and current analytical detection limits (around 1 ng/L for commercial laboratories). Some jurisdictions (e.g., Australia, Canada) have deemed uncertainty in quantifying water-fish bioaccumulation too great and set fish tissue action levels in lieu of water criteria. Current dynamics associated with the emerging and evolving science of PFAS toxicity, exposure, and environmental fate (i.e., data gaps and uncertainty), as well as the continuous release of scientific updates, pose a challenge to setting regulatory limits. Integr Environ Assess Manag 2024;20:36-58. © 2023 AECOM Technical Services, Inc and The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

A protection scheme for MMC–HVDC grid based on blocking time of converter station

This paper proposes a local protection scheme for the high voltage direct current grid based on the modular multilevel converter (MMC-HVDC), which determines the protection action time by blocking time of converter station and cuts the fault line by the coordination of action time. In view of the problem that the first protection action will accelerate the blocking of other converter stations, the protection action time margin is set in order to make the protection act in advance to remove the fault before any converter is blocked. By defining the virtual blocking time of the inverter station, the protection criterion of all the converter stations is unified and the selectivity of protection is guaranteed. The proposed scheme fully considers the coordination between the protection action and the blocking of converter station, and can selectively cut off fault lines according to the severity of overcurrent of the bridge arm of the converter. Simulation results verify the effectiveness of the proposed protection scheme.

Pilot Protection Based on Two-Dimensional Space Projection of Dual Differential Currents for Lines Connecting MMC–HVDC Stations

As an important topic of power system protection, protection algorithm for transmission lines connecting MMC-based converter stations has attracted extensive attention. This article proposes a new time-domain pilot protection based on two-dimensional space projection of dual differential currents for lines connecting converter stations. The dual differential currents, i.e., original and virtual differential currents, are projected into two-dimensional space. Subsequently, the dynamic trajectories of dual differential currents under various circumstances are elaborated. On this basis, the non-operating zone and internal fault index are defined, whereby the criterion of pilot protection is developed. Afterwards, the operating characteristic of the proposed pilot protection is analyzed under various circumstances. The performance of proposed pilot protection is widely assessed using PSCAD and RTDS. The contribution of this article lies in a new time-domain pilot protection based current trajectory of dual differential currents, which exhibits exceptional performance in operating speed, sensitivity, complexity, tolerance to fault resistance, CT saturation and abnormal data, adaptability to operation mode of MMC.

Evaluative analysis for standardized protection criteria against single and multiple lightning strikes in hybrid PV-wind energy systems

Evaluative analysis for standardized protection criteria against single and multiple lightning strikes in hybrid PV-wind energy systems

A novel pilot protection method for UHVDC transmission lines based on U-I characteristics

As one of the principal protections of UHVDC transmission lines, pilot protection requires strict synchronization and small data flow by exchanging the current on both terminals under the limitation of DC protection action rapidity. To solve this problem, this paper finds that the DC voltage and current on both terminals of the line have different plane distribution characteristics when faults occur internally and externally in the system area, and then advances a novel pilot protection method for UHVDC transmission lines based on U-I characteristics. By setting up the U-I plane with DC voltage and current as variables, analyzing the dynamic trajectory of the real-time captured U-I plane, constructing protection criteria based on the U-I plane on the rectifier side and inverter side separately, and finally converting the judgment results into state information. Both terminals of the line identify the fault location by exchanging the longitudinal comparison of state information. This protection project only utilizes the instant tracks of voltage and current in the rectifier side and inverter side at the time of fault to judge. The principle is simple and can quickly locate faults. The state messages of the two terminals are not modified by the data asynchrony on both terminals. This protection method is convenient for setting, has high sensitivity, and can quickly identify interior and exterior faults. The results are testified by theoretical analysis and simulation verification.

Adaptive additional current-based line differential protection in the presence of converter- interfaced sources with four quadrant operation capability

As typical representatives of converter-interfaced sources with four quadrant operation capability, battery energy storage station (BESS) and VSC-HVDC station behave differently with synchronous generator. This leads to the high risk of incorrect operation of current differential protection (CDP), seriously threatening the security of transmission network. Motivated by this issue, this paper presents adaptive additional current-based differential protection (AAC-DP). Adaptive additional current is introduced to modify the criterion of current differential protection. Ulteriorly, the unified expression of adaptive additional current for internal and external faults is designed. Adaptive additional current can increase the sensitivity during internal fault, whereas it improves the security during external fault. The sensitivity and dependability of AAC-DP was widely evaluated by changing operation mode, fault condition, and type of power source using PSCAD and RTDS-based experimental platform. Also, the adverse factors, such as saturation and error of current transformer(CT), and noise, were taken into account; thereof, the excellent security of AAC-DP was confirmed. The results confirm that AAC-DP exhibits excellent performance in operating speed, sensitivity, the adaptation to fault behaviors of BESS and VSC-HVDC, and robustness against saturation and error of CT, and noise.

Single-ended DC line protection scheme based on first peak time of current-limiting reactor voltage

Fast and sensitive DC line protection is an important guarantee for the security of the flexible DC grid. However, the reliability and sensitivity of the DC line protection are greatly affected by the high fault resistance. To overcome this problem, this paper proposes a novel single-ended line protection scheme for multi-terminal flexible DC grid. Firstly, the propagation characteristics of traveling wave after the internal and external faults are analyzed. Furthermore, a single-ended protection criterion based on the first peak time of current-limiting reactor transient voltage is proposed to distinguish the internal and forward external faults, which is independent of simulation. Then, based on the change characteristics of fault component current, a fault direction criterion and fault pole identification criterion are constructed to identify the backward fault and fault pole, respectively. Finally, extensive simulations and experiments show that the proposed protection scheme can identify the fault quickly and sensitively even for the internal remote-end fault with high fault resistance.

A Rotor Ground Fault Protection Method Based on Injection Principle for Variable Speed Pumped Storage Generator-Motor

Three-phase AC excitation is adopted in the variable speed pumped storage generator-motors, which is different from the DC excitation in traditional synchronous generators. The special rotor winding structure makes the existing rotor ground fault protection methods no longer applicable. Therefore, a rotor ground fault protection method for variable speed pumped storage generator-motor is proposed in this paper. Considering that there is no precondition for additional installation of the injection device at the rotor winding neutral point, the rotor ground fault protection scheme is proposed by connecting the injection device through current limiting resistors outside the rotor winding terminals. The key parameters of injection source, band-pass filter, and current limiting resistance are analyzed and calculated. Then, the online calculation methods of grounding resistance and grounding current are proposed based on the injection equivalent circuit. On this basis, the composite protection criterion considering grounding resistance and grounding current is constructed, and the protection outlet mode is clarified. Simulation and experiments verify the effectiveness of the proposed method.

Environmental Assessment of Coastal Sand Mining Using Proposed DPSIR Criteria: A Case of Hai Phong

The environmental impact of coastal sand mining activities in Hai Phong city was assessed using ten proposed sustainable criteria for socioeconomic development, and ecological and environmental protection. These ten criteria were developed by the analysis of the DynamicsPressure-State-Impact-Response (DPSIR) framework, including one driver and pressure criterion (D and P), seven status and impact criteria (S and I), and two response criteria (R). Each criterion is quantified according to five specific evaluation criteria corresponding to the evaluation score from 1 to 5. The results of the ten criterion application for environmental impact assessment of coastal mining Hai Phong by weighting show that the areas with economic activities, benthic biodiversity, and coastal ecosystems are most negatively impacted (score 4/5 and 3.5/5). Other subjects suffer low to moderate impacts (score 1/5 to 3/5). The environmental impact of sand mining (2015-2020) is generally moderate (score ranging from 2/5 to 3/5). The set of adjusted criteria can be applied to similar activities in coastal provinces and cities in Vietnam

The Effect of Anthropogenic Activities on the Fish Fauna of the Devrez Stream (Turkiye)

In this study, fish species diversity and protection criteria, habitat evaluation, and threat elements of the ichthyofauna of the Devrez Stream were examined monthly between April 2020 and March 2021. Eight fish taxa (7 natives, 1 non-native) belonging to four families (Cyprinidae, Gobionidae, Leuciscidae, Gobiidae) were identified. Chondrostoma angorense Elvira, 1987 (endemic) from the mentioned species was reported for the first time in the Devrez Stream. Squalius sp. (32.5%), Chondrostoma angorense (24.4%), Capoeta tinca (23.9%), and Alburnoides freyhofi (11.1%) were the most common and abundant species while Pseudorasbora parva (0.5%), Barbus anatolicus (1.2%), Alburnus goekhani (2.4%) and Neogobius fluviatilis (4%) were the most rarely encountered species in the stream. According to our observations, drought, agricultural irrigation, and Devrez Kızlaryolu Dam, which is under construction, were considered major threats to the fish fauna.

Coexistence Analysis Between IMT-2020 and AES operating in L Band on a Final Approach

This paper is regarding the statistical coexistence analysis between a cluster of International Mobile Telecommunication 2020 (IMT-2020) Base Stations and an Aircraft Earth Station (AES) operating during flight time in the L Band on a final approach. We assess the cumulative distribution function (CDF) of interference-over-noise ratio (INR) considering the fuselage attenuation contribution and compare it with the AES protection criteria. Our coexistence analysis approach considers the use of a high gain AES commercial antenna model, for an aircraft at two different altitudes, 187 m and 83 m, for 3600 m and 1600 m of horizontal distance from the runway threshold, respectively. Therefore, considering the IMT-2020 suburban scenario near the airport, simulation results presented an INR that met the protection criteria for 100% and 99.95% of the time for the distances of 3600 m and 1600 m from the runway, respectively, making the spectrum sharing feasible between systems. To the best of our knowledge, this is the first time in the literature that fuselage attenuation considering part of the plane, in the L-band is presented in a statistical coexistence analysis.

UJI EFEKTIFITAS EKSTRAK KULIT KULIM (Scorodocarpus borneensis Becc) SEBAGAI REPELLENT ANTI NYAMUK

The use of Scorodocarpus borneensis Becc as wood causes its availability in nature to decrease. An alternative step to utilize and maintain the availability of Kulim in nature is to utilize Scorodocarpus borneensis Becc’s bark extract. The bioactive substances and scent of Scorodocarpus borneensis Becc are considered capable of repelling insects and replacing DEET in chemical mosquito repellent raw materials. The use of Kulim wood extract is considered to be far better than the use of chemicals that can affect human health. This research was conducted in three laboratories, namely the forestry laboratory, organic chemistry laboratory and natural synthesis and chemical engineering laboratory. The parameters to know the quality of the extract from the bark of the Scorodocarpus borneensis Becc’s branch were yield observation, color observation, odor test and skin sensitivity, phytochemical test and the extract effectiveness test against mosquitoes which were expected to be in accordance with the criteria of the pesticide commission of the Department of Agriculture in 1995. The results showed that the yield from Scorodocarpus borneensis Becc’s wood extract was found to be worth 0.83%, the color of the extract was brown because it used water solvent, the distinctive aroma of the Scorodocarpus borneensis Becc was not found in the extract because it was dominated by tannins and the extract felt warm on the skin, phytochemical tests showed that the kulim extract contained substances such as saponins, phenolic, steroids and tannins as well as the effectiveness test of the extract against mosquitoes found a protection result of 44% which has not been able to meet the standard of repellent protection criteria from the Pesticide Commission of the Department of Agriculture in 1995.

Protecting Sleep Hygiene in the PICU: A Quality Improvement Project.

To increase the number of nights without sleep interruptions for routine tasks in recovering PICU patients. Prospective quality improvement project. Single-center, free-standing, tertiary children's hospital. Patients admitted to the PICU for greater than 72 hours and eligible for early mobilization. A multidisciplinary sleep hygiene team was created to improve sleep hygiene in critically ill patients eligible for early mobilization. This team rewrote local nursing policies to avoid routine tasks between 11 pm and 5 am . The team provided periodic control chart updates to staff detailing progress made protecting sleep. Discussions of sleep hygiene were added to the daily goal sheet and a sleep hygiene order set was created. Finally, the PICU quality dashboard was modified to show whether a sleep hygiene order set was initiated in eligible patients. Routine tasks were defined as daily chest radiographs, baths, routine tracheostomy care, central line dressing changes, twice daily medications, weights, and Foley care. After a year of data collection, avoidance of routine pupillary examinations was added to the sleep protection criteria. Baseline data was collected for 2 months prior to the creation of the sleep hygiene team. Screening of eligible patients occurred 1 week each month. The data were analyzed utilizing control charts. Baseline data demonstrated 32% of PICU patients without sleep interruptions. The centerline increased to 58% after the initial interventions but dropped to 33% after inclusion of pupillary checks. Following the introduction of the daily goal sheet, sleep hygiene order set, and tracking on the quality board, 49% of patients went without interruptions. The initiation of a sleep hygiene team along with retiming routine tasks, daily discussions on rounds with the daily goal sheet, introduction of a sleep hygiene order set, and transparent tracking improved the percentage of patients with protected sleep.

Chinese Technical Guideline for Deriving Water Quality Criteria for Protection of Freshwater Organisms

In recent years, China has determined the national goal of "developing national environmental criteria", thereby promoting the rapid development of environmental quality criteria research in China. In 2017, the Ministry of Ecology and Environment of China (MEEC, formerly the Ministry of Environmental Protection of China) issued the technical guideline for deriving water quality criteria (WQC) for protection of freshwater organisms (HJ 831-2017), and in 2022, they organized the guideline revision and issued an updated version (HJ 831-2022). The primary contents of the revision included the following. The minimum toxicity data requirements were upgraded from 6 to 10, and the species mean toxicity value was replaced by the same effect toxicity value for the criteria calculation. It is now required that the tested organisms must be distributed in China's natural fresh waters, and the toxicity data of non-native model species will no longer be used. The list of freshwater invasive species in China that cannot be used as test species was added into the guideline. The acute/chronic ratio (ACR) method for the criteria derivation and the extreme value model were deleted, and the provisions for testing the toxicity data distribution were also deleted. The exposure time of the toxicity test of various tested organisms was refined, and the priority of the toxicity data was clearly specified. This paper introduces the framework and specific technical requirements of HJ 831-2022 in detail, including data collection, pre-processing of toxicity data, criteria derivation, fitting models, and quality control. This introduction is helpful for international peers to understand the latest research progress of China's WQC.

Investigation on the ballistic performance of the aluminum matrix composite armor with ceramic balls reinforcement under high velocity impact

In this research, the ballistic behavior of the ceramic-reinforced aluminum matrix composite plates is investigated to provide an optimal design for protecting against 7.62 mm bullet at the speed of 800 m/s experimentally and numerically. The target materials are Al5083 alloy as the metal matrix and alumina ceramic balls as the reinforcement. To simulate a 3D numerical model, ABAQUS FE code has been utilized. After validation the numerical model by experiments, the effect of ceramic ball weight percentage include 15%, 30% and 45% and the target thickness 20, 25 and 30 mm is considered on the ballistic results like the kinetic energy, residual velocity and depth of penetration. Finally, it was found that the specimen with 25 mm thickness and 30% alumina is optimum based on existing ballistic protection criteria.

Active hydrothermal vent ecosystems in the Indian Ocean are in need of protection

Deep-sea hydrothermal vent fields are among the most pristine and remarkable ecosystems on Earth. They are fueled by microbial chemosynthesis, harbor unique life and can be sources of precipitated mineral deposits. As the global demand for mineral resources rises, vent fields have been investigated for polymetallic sulfides (PMS) and biological resources. The International Seabed Authority (ISA) has issued 7 contracts for PMS exploration, including 4 licenses for vent fields in the Indian Ocean. Here, we provide a summary of the available ecological knowledge of Indian vent communities and we assess their vulnerability, sensitivity, ecological and biological significance. We combine and apply scientific criteria for Vulnerable Marine Ecosystems (VMEs) by FAO, Particular Sensitive Sea Areas (PSSAs) by IMO, and Ecologically or Biologically Significant Areas (EBSAs) by CBD. Our scientific assessment shows that all active vent fields in the Indian Ocean appear to meet all scientific criteria for protection, and both the high degree of uniqueness and fragility of these ecosystems stand out.