WorldWideScience

Sample records for critically loaded multi-server

  1. Critical Axial Load

    Directory of Open Access Journals (Sweden)

    Walt Wells

    2008-01-01

    Full Text Available Our objective in this paper is to solve a second order differential equation for a long, simply supported column member subjected to a lateral axial load using Heun's numerical method. We will use the solution to find the critical load at which the column member will fail due to buckling. We will calculate this load using Euler's derived analytical approach for an exact solution, as well as Euler's Numerical Method. We will then compare the three calculated values to see how much they deviate from one another. During the critical load calculation, it will be necessary to calculate the moment of inertia for the column member.

  2. Critical loads - assessment of uncertainty

    Energy Technology Data Exchange (ETDEWEB)

    Barkman, A.

    1998-10-01

    The effects of data uncertainty in applications of the critical loads concept were investigated on different spatial resolutions in Sweden and northern Czech Republic. Critical loads of acidity (CL) were calculated for Sweden using the biogeochemical model PROFILE. Three methods with different structural complexity were used to estimate the adverse effects of S0{sub 2} concentrations in northern Czech Republic. Data uncertainties in the calculated critical loads/levels and exceedances (EX) were assessed using Monte Carlo simulations. Uncertainties within cumulative distribution functions (CDF) were aggregated by accounting for the overlap between site specific confidence intervals. Aggregation of data uncertainties within CDFs resulted in lower CL and higher EX best estimates in comparison with percentiles represented by individual sites. Data uncertainties were consequently found to advocate larger deposition reductions to achieve non-exceedance based on low critical loads estimates on 150 x 150 km resolution. Input data were found to impair the level of differentiation between geographical units at all investigated resolutions. Aggregation of data uncertainty within CDFs involved more constrained confidence intervals for a given percentile. Differentiation as well as identification of grid cells on 150 x 150 km resolution subjected to EX was generally improved. Calculation of the probability of EX was shown to preserve the possibility to differentiate between geographical units. Re-aggregation of the 95%-ile EX on 50 x 50 km resolution generally increased the confidence interval for each percentile. Significant relationships were found between forest decline and the three methods addressing risks induced by S0{sub 2} concentrations. Modifying S0{sub 2} concentrations by accounting for the length of the vegetation period was found to constitute the most useful trade-off between structural complexity, data availability and effects of data uncertainty. Data

  3. The concept of target and critical loads

    International Nuclear Information System (INIS)

    Grigal, D.F.

    1991-09-01

    Target and critical loads were initially developed for assessment and control of acidic deposition, but are being considered for other air pollutants such as ozone and air-borne toxic compounds. These loads are based on thresholds, with damage assumed to occur above some defined level of deposition. Many of the historically proposed targets for acidic deposition were based on arbitrary interpretations of data. The concept of critical loads has recently separated from that of target loads. A critical load is the amount of pollutant deposition, determined by technical analysis, above which there is a specific deleterious ecological effect. A target load is the deposition, determined by political agreement, above which unacceptable ecological damage occurs; it may be greater than the critical load because of political or economic considerations, or less to conservatively account for uncertainty in the estimation of the critical load. Recent definitions of critical loads include recognition that each kind of ecosystem and effect may require a different load. Geographic regions contain a mosaic of aquatic and terrestrial resources. If precise knowledge leads to different critical loads for each system, then how is the regional target load established? For better or worse, target and critical loads are likely to be used to regulate air pollutants. The philosophy of their establishment as thresholds, their quantitative validity, and their application in regulation all require careful examination. 36 refs., 3 figs

  4. Weaknesses of a dynamic identity based authentication protocol for multi-server architecture

    OpenAIRE

    Han, Weiwei

    2012-01-01

    Recently, Li et al. proposed a dynamic identity based authentication protocol for multi-server architecture. They claimed their protocol is secure and can withstand various attacks. But we found some security loopholes in the protocol. Accordingly, the current paper demonstrates that Li et al.'s protocol is vulnerable to the replay attack, the password guessing attack and the masquerade attack.

  5. Simple bounds and monotonicity results for finite multi-server exponential tandem queues

    NARCIS (Netherlands)

    Dijk, van N.M.; Wal, van der J.

    1989-01-01

    Simple and computationally attractive lower and upper bounds are presented for the call congestion such as those representing multi-server loss or delay stations. Numerical computations indicate a potential usefulness of the bounds for quick engineering purposes. The bounds correspond to

  6. Middleware for multi-client and multi-server mobile applications

    NARCIS (Netherlands)

    Rocha, B.P.S.; Rezende, C.G.; Loureiro, A.A.F.

    2007-01-01

    With popularization of mobile computing, many developers have faced problems due to great heterogeneity of devices. To address this issue, we present in this work a middleware for multi-client and multi-server mobile applications. We assume that the middleware at the server side has no resource

  7. Nitrogen critical loads using biodiversity-related critical limits

    International Nuclear Information System (INIS)

    Posch, Maximilian; Aherne, Julian; Hettelingh, Jean-Paul

    2011-01-01

    Critical loads are widely used in the effects-based assessment of emission reduction policies. While the impacts of acidification have diminished, there is increasing concern regarding the effects of nitrogen deposition on terrestrial ecosystems. In this context much attention has been focussed on empirical critical loads as well as simulations with linked geochemistry-vegetation models. Surprisingly little attention has been paid to adapt the widely used simple mass balance approach. This approach has the well-established benefit of easy regional applicability, while incorporating specified critical chemical criteria to protect specified receptors. As plant occurrence/biodiversity is related to both the nutrient and acidity status of an ecosystem, a single abiotic factor (chemical criterion) is not sufficient. Rather than an upper limit for deposition (i.e., critical load), linked nutrient nitrogen and acidity chemical criteria for plant occurrence result in an 'optimal' nitrogen and sulphur deposition envelope. - Highlights: → Mass balance critical load approaches for nutrient nitrogen remain useful. → Biodiversity-related limits are related to nutrient and acidity status. → Nutrient and acidity chemical criteria lead to optimal deposition envelopes. → Optimal loads support effects-based emission reduction policies. - Biodiversity-related critical limits lead to optimal nitrogen and sulphur deposition envelopes for plant species or species compositions.

  8. Cryptanalysis and Improvement of a Biometric-Based Multi-Server Authentication and Key Agreement Scheme.

    Directory of Open Access Journals (Sweden)

    Chengqi Wang

    Full Text Available With the security requirements of networks, biometrics authenticated schemes which are applied in the multi-server environment come to be more crucial and widely deployed. In this paper, we propose a novel biometric-based multi-server authentication and key agreement scheme which is based on the cryptanalysis of Mishra et al.'s scheme. The informal and formal security analysis of our scheme are given, which demonstrate that our scheme satisfies the desirable security requirements. The presented scheme provides a variety of significant functionalities, in which some features are not considered in the most of existing authentication schemes, such as, user revocation or re-registration and biometric information protection. Compared with several related schemes, our scheme has more secure properties and lower computation cost. It is obviously more appropriate for practical applications in the remote distributed networks.

  9. Robust biometrics based authentication and key agreement scheme for multi-server environments using smart cards.

    Science.gov (United States)

    Lu, Yanrong; Li, Lixiang; Yang, Xing; Yang, Yixian

    2015-01-01

    Biometrics authenticated schemes using smart cards have attracted much attention in multi-server environments. Several schemes of this type where proposed in the past. However, many of them were found to have some design flaws. This paper concentrates on the security weaknesses of the three-factor authentication scheme by Mishra et al. After careful analysis, we find their scheme does not really resist replay attack while failing to provide an efficient password change phase. We further propose an improvement of Mishra et al.'s scheme with the purpose of preventing the security threats of their scheme. We demonstrate the proposed scheme is given to strong authentication against several attacks including attacks shown in the original scheme. In addition, we compare the performance and functionality with other multi-server authenticated key schemes.

  10. Cryptanalysis and Improvement of a Biometric-Based Multi-Server Authentication and Key Agreement Scheme

    Science.gov (United States)

    Wang, Chengqi; Zhang, Xiao; Zheng, Zhiming

    2016-01-01

    With the security requirements of networks, biometrics authenticated schemes which are applied in the multi-server environment come to be more crucial and widely deployed. In this paper, we propose a novel biometric-based multi-server authentication and key agreement scheme which is based on the cryptanalysis of Mishra et al.’s scheme. The informal and formal security analysis of our scheme are given, which demonstrate that our scheme satisfies the desirable security requirements. The presented scheme provides a variety of significant functionalities, in which some features are not considered in the most of existing authentication schemes, such as, user revocation or re-registration and biometric information protection. Compared with several related schemes, our scheme has more secure properties and lower computation cost. It is obviously more appropriate for practical applications in the remote distributed networks. PMID:26866606

  11. Robust biometrics based authentication and key agreement scheme for multi-server environments using smart cards.

    Directory of Open Access Journals (Sweden)

    Yanrong Lu

    Full Text Available Biometrics authenticated schemes using smart cards have attracted much attention in multi-server environments. Several schemes of this type where proposed in the past. However, many of them were found to have some design flaws. This paper concentrates on the security weaknesses of the three-factor authentication scheme by Mishra et al. After careful analysis, we find their scheme does not really resist replay attack while failing to provide an efficient password change phase. We further propose an improvement of Mishra et al.'s scheme with the purpose of preventing the security threats of their scheme. We demonstrate the proposed scheme is given to strong authentication against several attacks including attacks shown in the original scheme. In addition, we compare the performance and functionality with other multi-server authenticated key schemes.

  12. Cryptanalysis and Improvement of a Biometric-Based Multi-Server Authentication and Key Agreement Scheme.

    Science.gov (United States)

    Wang, Chengqi; Zhang, Xiao; Zheng, Zhiming

    2016-01-01

    With the security requirements of networks, biometrics authenticated schemes which are applied in the multi-server environment come to be more crucial and widely deployed. In this paper, we propose a novel biometric-based multi-server authentication and key agreement scheme which is based on the cryptanalysis of Mishra et al.'s scheme. The informal and formal security analysis of our scheme are given, which demonstrate that our scheme satisfies the desirable security requirements. The presented scheme provides a variety of significant functionalities, in which some features are not considered in the most of existing authentication schemes, such as, user revocation or re-registration and biometric information protection. Compared with several related schemes, our scheme has more secure properties and lower computation cost. It is obviously more appropriate for practical applications in the remote distributed networks.

  13. Information Interpretation Code For Providing Secure Data Integrity On Multi-Server Cloud Infrastructure

    OpenAIRE

    Sathiya Moorthy Srinivsan; Chandrasekar Chaillah

    2014-01-01

    Data security is one of the biggest concerns in cloud computing environment. Although the advantages of storing data in cloud computing environment is extremely high, there arises a problem related to data missing. CyberLiveApp (CLA) supports secure application development between multiple users, even though cloud users distinguish their vision privileges during storing of data. But CyberLiveApp failed to integrate the system with certain cloud-based computing environments on multi-server. En...

  14. Multi-server blind quantum computation over collective-noise channels

    Science.gov (United States)

    Xiao, Min; Liu, Lin; Song, Xiuli

    2018-03-01

    Blind quantum computation (BQC) enables ordinary clients to securely outsource their computation task to costly quantum servers. Besides two essential properties, namely correctness and blindness, practical BQC protocols also should make clients as classical as possible and tolerate faults from nonideal quantum channel. In this paper, using logical Bell states as quantum resource, we propose multi-server BQC protocols over collective-dephasing noise channel and collective-rotation noise channel, respectively. The proposed protocols permit completely or almost classical client, meet the correctness and blindness requirements of BQC protocol, and are typically practical BQC protocols.

  15. An efficient biometric and password-based remote user authentication using smart card for Telecare Medical Information Systems in multi-server environment.

    Science.gov (United States)

    Maitra, Tanmoy; Giri, Debasis

    2014-12-01

    The medical organizations have introduced Telecare Medical Information System (TMIS) to provide a reliable facility by which a patient who is unable to go to a doctor in critical or urgent period, can communicate to a doctor through a medical server via internet from home. An authentication mechanism is needed in TMIS to hide the secret information of both parties, namely a server and a patient. Recent research includes patient's biometric information as well as password to design a remote user authentication scheme that enhances the security level. In a single server environment, one server is responsible for providing services to all the authorized remote patients. However, the problem arises if a patient wishes to access several branch servers, he/she needs to register to the branch servers individually. In 2014, Chuang and Chen proposed an remote user authentication scheme for multi-server environment. In this paper, we have shown that in their scheme, an non-register adversary can successfully logged-in into the system as a valid patient. To resist the weaknesses, we have proposed an authentication scheme for TMIS in multi-server environment where the patients can register to a root telecare server called registration center (RC) in one time to get services from all the telecare branch servers through their registered smart card. Security analysis and comparison shows that our proposed scheme provides better security with low computational and communication cost.

  16. Cryptanalysis and improvement of a biometrics-based authentication and key agreement scheme for multi-server environments.

    Science.gov (United States)

    Yang, Li; Zheng, Zhiming

    2018-01-01

    According to advancements in the wireless technologies, study of biometrics-based multi-server authenticated key agreement schemes has acquired a lot of momentum. Recently, Wang et al. presented a three-factor authentication protocol with key agreement and claimed that their scheme was resistant to several prominent attacks. Unfortunately, this paper indicates that their protocol is still vulnerable to the user impersonation attack, privileged insider attack and server spoofing attack. Furthermore, their protocol cannot provide the perfect forward secrecy. As a remedy of these aforementioned problems, we propose a biometrics-based authentication and key agreement scheme for multi-server environments. Compared with various related schemes, our protocol achieves the stronger security and provides more functionality properties. Besides, the proposed protocol shows the satisfactory performances in respect of storage requirement, communication overhead and computational cost. Thus, our protocol is suitable for expert systems and other multi-server architectures. Consequently, the proposed protocol is more appropriate in the distributed networks.

  17. Paying for Express Checkout: Competition and Price Discrimination in Multi-Server Queuing Systems

    Science.gov (United States)

    Deck, Cary; Kimbrough, Erik O.; Mongrain, Steeve

    2014-01-01

    We model competition between two firms selling identical goods to customers who arrive in the market stochastically. Shoppers choose where to purchase based upon both price and the time cost associated with waiting for service. One seller provides two separate queues, each with its own server, while the other seller has a single queue and server. We explore the market impact of the multi-server seller engaging in waiting cost-based-price discrimination by charging a premium for express checkout. Specifically, we analyze this situation computationally and through the use of controlled laboratory experiments. We find that this form of price discrimination is harmful to sellers and beneficial to consumers. When the two-queue seller offers express checkout for impatient customers, the single queue seller focuses on the patient shoppers thereby driving down prices and profits while increasing consumer surplus. PMID:24667809

  18. ANALYSIS OF MULTI-SERVER QUEUEING SYSTEM WITH PREEMPTIVE PRIORITY AND REPEATED CALLS

    Directory of Open Access Journals (Sweden)

    S. A. Dudin

    2015-01-01

    Full Text Available Multi-server retrial queueing system with no buffer and two types of customers is analyzed as the model of cognitive radio system. Customers of type 1 have a preemptive priority. Customers of both types arrive according to Markovian Arrival Processes. Service times have exponential distribution with parameter depending on the customer type. Type 2 customers are admitted for service only if the number of busy servers is less than the predefined threshold. The rejected type 2 customers retry for the service. Existence condition of the stationary mode of system operation is derived. Formulas for computing key performance measures of the system are presented.

  19. Paying for express checkout: competition and price discrimination in multi-server queuing systems.

    Directory of Open Access Journals (Sweden)

    Cary Deck

    Full Text Available We model competition between two firms selling identical goods to customers who arrive in the market stochastically. Shoppers choose where to purchase based upon both price and the time cost associated with waiting for service. One seller provides two separate queues, each with its own server, while the other seller has a single queue and server. We explore the market impact of the multi-server seller engaging in waiting cost-based-price discrimination by charging a premium for express checkout. Specifically, we analyze this situation computationally and through the use of controlled laboratory experiments. We find that this form of price discrimination is harmful to sellers and beneficial to consumers. When the two-queue seller offers express checkout for impatient customers, the single queue seller focuses on the patient shoppers thereby driving down prices and profits while increasing consumer surplus.

  20. Peak load-impulse characterization of critical pulse loads in structural dynamics

    International Nuclear Information System (INIS)

    Abrahamson, G.R.; Lindberg, H.E.

    1975-01-01

    In presenting the characterization scheme, some general features are described first. A detailed analysis is given for the rigid-plastic system of one degree of freedom to illustrate the calculation of critical load curves in terms of peak load and impulse. This is followed by the presentation of critical load curves for uniformly loaded rigid-plastic beams and plates and for dynamic buckling of cylindrical shells under uniform lateral loads. The peak load-impulse characterization of critical pulse loads is compared with the dynamic load factor characterization, and some aspects of the history of the peak load-pulse scheme are presented. (orig./HP) [de

  1. An exact solution for the state probabilities of the multi-class, multi-server queue with preemptive priorities

    NARCIS (Netherlands)

    Sleptchenko, Andrei; van Harten, Aart; van der Heijden, Matthijs C.

    2005-01-01

    We consider a multi-class, multi-server queueing system with preemptive priorities. We distinguish two groups of priority classes that consist of multiple customer types, each having their own arrival and service rate. We assume Poisson arrival processes and exponentially distributed service times.

  2. An Improvement of Robust Biometrics-Based Authentication and Key Agreement Scheme for Multi-Server Environments Using Smart Cards.

    Science.gov (United States)

    Moon, Jongho; Choi, Younsung; Jung, Jaewook; Won, Dongho

    2015-01-01

    In multi-server environments, user authentication is a very important issue because it provides the authorization that enables users to access their data and services; furthermore, remote user authentication schemes for multi-server environments have solved the problem that has arisen from user's management of different identities and passwords. For this reason, numerous user authentication schemes that are designed for multi-server environments have been proposed over recent years. In 2015, Lu et al. improved upon Mishra et al.'s scheme, claiming that their remote user authentication scheme is more secure and practical; however, we found that Lu et al.'s scheme is still insecure and incorrect. In this paper, we demonstrate that Lu et al.'s scheme is vulnerable to outsider attack and user impersonation attack, and we propose a new biometrics-based scheme for authentication and key agreement that can be used in multi-server environments; then, we show that our proposed scheme is more secure and supports the required security properties.

  3. An Improvement of Robust Biometrics-Based Authentication and Key Agreement Scheme for Multi-Server Environments Using Smart Cards

    Science.gov (United States)

    Moon, Jongho; Choi, Younsung; Jung, Jaewook; Won, Dongho

    2015-01-01

    In multi-server environments, user authentication is a very important issue because it provides the authorization that enables users to access their data and services; furthermore, remote user authentication schemes for multi-server environments have solved the problem that has arisen from user’s management of different identities and passwords. For this reason, numerous user authentication schemes that are designed for multi-server environments have been proposed over recent years. In 2015, Lu et al. improved upon Mishra et al.’s scheme, claiming that their remote user authentication scheme is more secure and practical; however, we found that Lu et al.’s scheme is still insecure and incorrect. In this paper, we demonstrate that Lu et al.’s scheme is vulnerable to outsider attack and user impersonation attack, and we propose a new biometrics-based scheme for authentication and key agreement that can be used in multi-server environments; then, we show that our proposed scheme is more secure and supports the required security properties. PMID:26709702

  4. Critical traffic loading for the design of prestressed concrete bridge

    International Nuclear Information System (INIS)

    Hassan, M.I.U.

    2009-01-01

    A study has been carried out to determine critical traffic loadings for the design of bridge superstructures. The prestressed concrete girder bridge already constructed in Lahore is selected for the analysis as an example. Standard traffic loadings according to AASHTO (American Association of State Highway and Transportation Officials) and Pakistan Highway Standards are used for this purpose. These include (1) HL-93 Truck, (2) Lane and (3) Tandem Loadings in addition to (4) Military tank loading, (5) Class-A, (6) Class-B and (7) Class-AA loading, (8) NLC (National Logistic Cell) and (9) Volvo truck loadings. Bridge superstructure including transom beam is analyzed Using ASD and LRFD (Load and Resistance Factor Design) provisions of AASHTO specifications. For the analysis, two longer and shorter spans are selected. This includes the analysis of bridge deck; interior and exterior girder; a typical transom beam and a pier. Dead and live loading determination is carried out using both computer aided and manual calculations. Evaluation of traffic loadings is done for all the bridge components to find out the critical loading. HL-93 loading comes out to be the most critical loading and where this loading is not critical in case of bridge decks; a factor of 1.15 is introduced to make it equivalent with HL-93 -Ioading. SAP-2000 (Structural Engineering Services of Pakistan) and MS-Excel is employed for analysis of bridge superstructure subjected to this loading. Internal forces are obtained for the structural elements of the bridge for all traffic loadings mentioned. It is concluded that HL-93 loading can be used for the design of prestressed concrete girder bridge. Bridge design authorities like NHA (National Highway Authority) and different cities development authorities are using different standard traffic loadings. A number of suggestions are made from the results of the research work related to traffic loadings and method of design. These recommendations may be

  5. An Enhanced Biometric Based Authentication with Key-Agreement Protocol for Multi-Server Architecture Based on Elliptic Curve Cryptography.

    Directory of Open Access Journals (Sweden)

    Alavalapati Goutham Reddy

    Full Text Available Biometric based authentication protocols for multi-server architectures have gained momentum in recent times due to advancements in wireless technologies and associated constraints. Lu et al. recently proposed a robust biometric based authentication with key agreement protocol for a multi-server environment using smart cards. They claimed that their protocol is efficient and resistant to prominent security attacks. The careful investigation of this paper proves that Lu et al.'s protocol does not provide user anonymity, perfect forward secrecy and is susceptible to server and user impersonation attacks, man-in-middle attacks and clock synchronization problems. In addition, this paper proposes an enhanced biometric based authentication with key-agreement protocol for multi-server architecture based on elliptic curve cryptography using smartcards. We proved that the proposed protocol achieves mutual authentication using Burrows-Abadi-Needham (BAN logic. The formal security of the proposed protocol is verified using the AVISPA (Automated Validation of Internet Security Protocols and Applications tool to show that our protocol can withstand active and passive attacks. The formal and informal security analyses and performance analysis demonstrates that the proposed protocol is robust and efficient compared to Lu et al.'s protocol and existing similar protocols.

  6. Cryptanalysis and improvement of a biometrics-based authentication and key agreement scheme for multi-server environments

    Science.gov (United States)

    Zheng, Zhiming

    2018-01-01

    According to advancements in the wireless technologies, study of biometrics-based multi-server authenticated key agreement schemes has acquired a lot of momentum. Recently, Wang et al. presented a three-factor authentication protocol with key agreement and claimed that their scheme was resistant to several prominent attacks. Unfortunately, this paper indicates that their protocol is still vulnerable to the user impersonation attack, privileged insider attack and server spoofing attack. Furthermore, their protocol cannot provide the perfect forward secrecy. As a remedy of these aforementioned problems, we propose a biometrics-based authentication and key agreement scheme for multi-server environments. Compared with various related schemes, our protocol achieves the stronger security and provides more functionality properties. Besides, the proposed protocol shows the satisfactory performances in respect of storage requirement, communication overhead and computational cost. Thus, our protocol is suitable for expert systems and other multi-server architectures. Consequently, the proposed protocol is more appropriate in the distributed networks. PMID:29534085

  7. An Enhanced Biometric Based Authentication with Key-Agreement Protocol for Multi-Server Architecture Based on Elliptic Curve Cryptography

    Science.gov (United States)

    Reddy, Alavalapati Goutham; Das, Ashok Kumar; Odelu, Vanga; Yoo, Kee-Young

    2016-01-01

    Biometric based authentication protocols for multi-server architectures have gained momentum in recent times due to advancements in wireless technologies and associated constraints. Lu et al. recently proposed a robust biometric based authentication with key agreement protocol for a multi-server environment using smart cards. They claimed that their protocol is efficient and resistant to prominent security attacks. The careful investigation of this paper proves that Lu et al.’s protocol does not provide user anonymity, perfect forward secrecy and is susceptible to server and user impersonation attacks, man-in-middle attacks and clock synchronization problems. In addition, this paper proposes an enhanced biometric based authentication with key-agreement protocol for multi-server architecture based on elliptic curve cryptography using smartcards. We proved that the proposed protocol achieves mutual authentication using Burrows-Abadi-Needham (BAN) logic. The formal security of the proposed protocol is verified using the AVISPA (Automated Validation of Internet Security Protocols and Applications) tool to show that our protocol can withstand active and passive attacks. The formal and informal security analyses and performance analysis demonstrates that the proposed protocol is robust and efficient compared to Lu et al.’s protocol and existing similar protocols. PMID:27163786

  8. An Enhanced Biometric Based Authentication with Key-Agreement Protocol for Multi-Server Architecture Based on Elliptic Curve Cryptography.

    Science.gov (United States)

    Reddy, Alavalapati Goutham; Das, Ashok Kumar; Odelu, Vanga; Yoo, Kee-Young

    2016-01-01

    Biometric based authentication protocols for multi-server architectures have gained momentum in recent times due to advancements in wireless technologies and associated constraints. Lu et al. recently proposed a robust biometric based authentication with key agreement protocol for a multi-server environment using smart cards. They claimed that their protocol is efficient and resistant to prominent security attacks. The careful investigation of this paper proves that Lu et al.'s protocol does not provide user anonymity, perfect forward secrecy and is susceptible to server and user impersonation attacks, man-in-middle attacks and clock synchronization problems. In addition, this paper proposes an enhanced biometric based authentication with key-agreement protocol for multi-server architecture based on elliptic curve cryptography using smartcards. We proved that the proposed protocol achieves mutual authentication using Burrows-Abadi-Needham (BAN) logic. The formal security of the proposed protocol is verified using the AVISPA (Automated Validation of Internet Security Protocols and Applications) tool to show that our protocol can withstand active and passive attacks. The formal and informal security analyses and performance analysis demonstrates that the proposed protocol is robust and efficient compared to Lu et al.'s protocol and existing similar protocols.

  9. Load flow analysis using decoupled fuzzy load flow under critical ...

    African Journals Online (AJOL)

    user

    3.1 Maximum range selection of input and output variables: ..... Wong K. P., Li A., and Law M.Y., “ Advanced Constrained Genetic Algorithm Load Flow Method”, IEE Proc. ... Dr. Parimal Acharjee passed B.E.E. from North Bengal University ...

  10. Potential nitrogen critical loads for northern Great Plains grassland vegetation

    Science.gov (United States)

    Symstad, Amy J.; Smith, Anine T.; Newton, Wesley E.; Knapp, Alan K.

    2015-01-01

    The National Park Service is concerned that increasing atmospheric nitrogen deposition caused by fossil fuel combustion and agricultural activities could adversely affect the northern Great Plains (NGP) ecosystems in its trust. The critical load concept facilitates communication between scientists and policy makers or land managers by translating the complex effects of air pollution on ecosystems into concrete numbers that can be used to inform air quality targets. A critical load is the exposure level below which significant harmful effects on sensitive elements of the environment do not occur. A recent review of the literature suggested that the nitrogen critical load for Great Plains vegetation is 10-25 kg N/ha/yr. For comparison, current atmospheric nitrogen deposition in NGP National Park Service (NPS) units ranges from ~4 kg N/ha/yr in the west to ~13 kg N/ha/yr in the east. The suggested critical load, however, was derived from studies far outside of the NGP, and from experiments investigating nitrogen loads substantially higher than current atmospheric deposition in the region.Therefore, to better determine the nitrogen critical load for sensitive elements in NGP parks, we conducted a four-year field experiment in three northern Great Plains vegetation types at Badlands and Wind Cave National Parks. The vegetation types were chosen because of their importance in NGP parks, their expected sensitivity to nitrogen addition, and to span a range of natural fertility. In the experiment, we added nitrogen at rates ranging from below current atmospheric deposition (2.5 kg N/ha/yr) to far above those levels but commensurate with earlier experiments (100 kg N/ha/yr). We measured the response of a variety of vegetation and soil characteristics shown to be sensitive to nitrogen addition in other studies, including plant biomass production, plant tissue nitrogen concentration, plant species richness and composition, non-native species abundance, and soil inorganic

  11. Insensitivity of proportional fairness in critically loaded bandwidth sharing networks

    NARCIS (Netherlands)

    Vlasiou, M.; Zhang, J.; Zwart, B.

    2014-01-01

    Proportional fairness is a popular service allocation mechanism to describe and analyze the performance of data networks at flow level. Recently, several authors have shown that the invariant distribution of such networks admits a product form distribution under critical loading. Assuming

  12. Critical loads for vegetation. Definition, use and limits

    International Nuclear Information System (INIS)

    Thimonier, A.; Dupouey, J.L.

    1993-01-01

    Vegetation is a key compartment of ecosystems. It contains a large part of the biodiversity at the species level. For the evaluation of critical loads, we have to separate different receptors: lower plants (algae, fungi, lichens and mosses) and vascular plants. Trees must be distinguished due to their economic value. We analyze the different changes that pollution produces on vegetation: the state of health of individuals, changes in the biology and genetics at the population level, changes in the biodiversity or the specific composition at the community level. Calculation of critical loads is based on observational or experimental studies, in more or less controlled environments. However, they cannot yet be obtained through models of vegetation changes. Some results have been acquired at the European level, mainly for critical loads for nitrogen, but these results have come mostly from Northern Europe. Moreover, only heathlands and acidic forests have been studied in depth. Critical loads for a lot of environment types are still unknown. Lower plants and interactions between vegetation and animals need more investigation

  13. Application of the critical loads approach in South Africa

    CSIR Research Space (South Africa)

    Van Tienhoven, AM

    1995-12-01

    Full Text Available , South Africa. Abstract. South Africa is the most industrialised country in southern Africa and stands at some risk from negative pollution i apa~ To the authors' knowledge, this paper presents the first attempt toapply the critical loads approach...

  14. Criticality conditions of heterogeneous energetic materials under shock loading

    Science.gov (United States)

    Nassar, Anas; Rai, Nirmal Kumar; Sen, Oishik; Udaykumar, H. S.

    2017-06-01

    Shock interaction with the microstructural heterogeneities of energetic materials can lead to the formation of locally heated regions known as hot spots. These hot spots are the potential sites where chemical reaction may be initiated. However, the ability of a hot spot to initiate chemical reaction depends on its size, shape and strength (temperature). Previous study by Tarver et al. has shown that there exists a critical size and temperature for a given shape (spherical, cylindrical, and planar) of the hot spot above which reaction initiation is imminent. Tarver et al. assumed a constant temperature variation in the hot spot. However, the meso-scale simulations show that the temperature distribution within a hot spot formed from processes such as void collapse is seldom constant. Also, the shape of a hot spot can be arbitrary. This work is an attempt towards development of a critical hot spot curve which is a function of loading strength, duration and void morphology. To achieve the aforementioned goal, mesoscale simulations are conducted on porous HMX material. The process is repeated for different loading conditions and void sizes. The hot spots formed in the process are examined for criticality depending on whether they will ignite or not. The metamodel is used to obtain criticality curves and is compared with the critical hot spot curve of Tarver et al.

  15. Critical loads and excess loads of cadmium, copper and lead for European forest soils

    NARCIS (Netherlands)

    Reinds, G.J.; Bril, J.; Vries, de W.; Groenenberg, J.E.; Breeuwsma, A.

    1995-01-01

    Recently, concern has arisen about the impact of the dispersion of heavy metals in Europe. Therefore, a study (ESQUAD) was initiated to assess critical loads and steady-state concentrations of cadmium, copper and lead for European forest soils. The calculation methods used strongly resemble those

  16. Exceedance of critical loads and of critical limits impacts tree nutrition across Europe

    DEFF Research Database (Denmark)

    Waldner, P.; Thimonier, A.; Graf Pannatier, E.

    2015-01-01

    solution tended to be related to less favourable nutritional status. Context Forests have been exposed to elevated atmospheric deposition of acidifying and eutrophying sulphur and nitrogen compounds for decades. Critical loads have been identified, below which damage due to acidification and eutrophication...... are not expected to occur. Aims We explored the relationship between the exceedance of critical loads and inorganic nitrogen concentration, the base cation to aluminium ratio in soil solutions, as well as the nutritional status of trees. Methods We used recent data describing deposition, elemental concentrations....... Conclusion The findings support the hypothesis that elevated nitrogen and sulphur deposition can lead to imbalances in tree nutrition....

  17. Results of the critical experiments concerning OTTO loading at the critical HTR-test facility KAHTER

    International Nuclear Information System (INIS)

    Drueke, V.; Litzow, W.; Paul, N.

    1982-12-01

    Critical experiments concerning OTTO loading are described. In the KAHTER facility an OTTO loading has been simulated, therefore the original KAHTER assembly was reconstructed. The determination of critical masses and reactivity worths of control rods and of additional absorber rods in the top reflector and in the upper cavity was of main interest for comparison with reactor following calculations. Besides this, reaction rates in different energy regions were measured in the upper part of the core, in the cavity and top reflector. (orig.) [de

  18. Eutrophic lichens respond to multiple forms of N: implications for critical levels and critical loads research

    Science.gov (United States)

    Sarah Jovan; Jennifer Riddell; Pamela E Padgett; Thomas Nash

    2012-01-01

    Epiphytic lichen communities are highly sensitive to excess nitrogen (N), which causes the replacement of native floras by N-tolerant, ‘‘weedy’’ eutrophic species. This shift is commonly used as the indicator of ecosystem ‘‘harm’’ in studies developing empirical critical levels (CLE) for ammonia (NH3) and critical loads (CLO) for N. To be most...

  19. Mass balance approaches to assess critical loads and target loads of heavy metals for terrestrial and aquatic ecosystems

    NARCIS (Netherlands)

    Vries, de W.; Groenenberg, J.E.; Posch, M.

    2015-01-01

    Critical loads of heavy metals address not only ecotoxicological effects on organisms in soils and surface waters, but also food quality in view of public health. A critical load for metals is the load resulting at steady state in a metal concentration in a compartment (e.g. soil solution, surface

  20. Calculation and mapping of critical loads in Europe: Status report 1993

    International Nuclear Information System (INIS)

    Downing, R.J.; Hettelingh, J.P.; De Smet, P.A.M.

    1993-01-01

    The work of the RIVM Coordination Center for Effects (CCE) and National Focal Centers (NFCs) for Mapping over the past two years is summarized. The primary task of the critical loads mapping program during this period was to compute and map critical loads of sulphur in Europe. Efforts were undertaken to enhance the scientific foundations and policy relevance of the critical load program, and to foster consensus among producers and users of this information by means of three workshops. The applied calculation methods are described, as well as the resulting critical loads maps, based upon the outcomes of the workshops. Chapter 2 contains the most recent maps (May 1993) of the critical load of acidity as well as the critical load of sulphur and critical sulphur deposition, which are derived from the critical load of acidity. The chapter also contains maps of the sulphur deposition in Europe in 1980 and 1990, and the resulting exceedances. In chapter 3 the methods and equations used to derive the maps of critical loads and exceedances of acidity and sulphur are described with emphasis on the advances in the calculation methods used since the first European critical loads maps were produced in 1991. In chapter 4 the methods to be used to compute and map critical loads in the future are presented. In chapter 5 an overview of the data inputs is given, and the methods of data handling performed by the CCE to produce the current European maps of critical loads. In chapter 6 the results of an uncertainty analysis is described, which was performed on the critical loads computation methodology to assess the reliability of the computation results and the importance of the various input variables. Chapter 7 provides some conclusions and recommendations resulting from the critical load mapping activities. In Appendix 1 the reports of the can be found, with additional maps of critical loads and background variables in Appendix 2. 15 figs., 11 tabs., 156 refs

  1. Critical acidity loads in France; Charges critiques d`acidite en France

    Energy Technology Data Exchange (ETDEWEB)

    Probst, A.; Party, J.P.; Fevrier, C. [Centre de Geochimie de la Surface (UPR 06251 du CNRS), 67 - Strasbourg (France); Dambrine, E. [Centre de Recherches Forestieres, INRA, 45 - Orleans (France); Thomas, A.L.; King, D. [Institut National de Recherches Agronomique (INRA), 45 - ORDON (France); Stussi, J.M. [Centre National de la Recherche Scientifique (CNRS), 54 - Vandoeuvre-les-Nancy (France)

    1997-12-31

    Based on results from several systematic forest and surface water monitoring programs, carried out in various parts of France as well as in Europe, acidity critical loads have been calculated for soils and surface waters; critical loads are presented for water and soils in crystalline mountainous regions such as Ardennes, Vosges and Massif Central; links with geochemistry, ecosystems and types of trees are discussed and perspectives are given for the calculation of acid and nitrogen critical loads on the whole France

  2. a model for the determination of the critical buckling load of self

    African Journals Online (AJOL)

    HP

    Considering the widespread use of this type of structure and the critical role it ... proposed by the model for the critical buckling load of self- supporting lattice tower, whose equivalent solid beam- ... stiffness, both material and geometric, [5, 6].

  3. Critical loads as a policy tool for protecting ecosystems from the effects of air pollutants

    Science.gov (United States)

    Douglas A. Burns; Tamara Blett; Richard Haeuber; Linda H. Pardo

    2008-01-01

    Framing the effects of air pollutants on ecosystems in terms of a "critical load" provides a meaningful approach for research scientists to communicate policy-relevant science to air-quality policy makers and natural resource managers. A critical-loads approach has been widely used to shape air-pollutant control policy in Europe since the 1980s, yet has only...

  4. Estimates of critical acid loads and exceedances for forest soils across the conterminous United States

    Science.gov (United States)

    Steven G. McNulty; Erika C. Cohen; Jennifer A. Moore Myers; Timothy J. Sullivan; Harbin Li

    2007-01-01

    Concern regarding the impacts of continued nitrogen and sulfur deposition on ecosystem health has prompted the development of critical acid load assessments for forest soils. A critical acid load is a quantitative estimate of exposure to one or more pollutants at or above which harmful acidification-related effects on sensitive elements of the environment occur. A...

  5. A conceptual framework: redifining forests soil's critical acid loads under a changing climate

    Science.gov (United States)

    Steven G. McNulty; Johnny L. Boggs

    2010-01-01

    Federal agencies of several nations have or are currently developing guidelines for critical forest soil acid loads. These guidelines are used to establish regulations designed to maintain atmospheric acid inputs below levels shown to damage forests and streams. Traditionally, when the critical soil acid load exceeds the amount of acid that the ecosystem can absorb, it...

  6. Methods for monitoring the initial load to critical in the fast test reactor

    International Nuclear Information System (INIS)

    Johnson, D.L.

    1975-08-01

    Conventional symmetric fuel loadings for the initial loading to critical of the Fast Test Reactor (FTR) are predicted to be more time consuming than asymmetric or trisector loadings. Potentially significant time savings can be realized by the latter, since adequate intermediate assessments of neutron multiplication can be made periodically without control rod reconnection in all trisectors. Experimental simulation of both loading schemes was carried out in the Reverse Approach to Critical (RAC) experiments in the Fast Test Reactor-Engineering Mockup Critical facility. Analyses of these experiments indicated that conventional source multiplication methods can be applied for monitoring either a symmetric or asymmetric fuel loading scheme equally well provided that detection efficiency corrections are employed. Methods for refining predictions of reactivity and count rates for the stages in a load to critical were also investigated. (auth)

  7. Mapping critical loads in Europe in the framework of the UN/CEE

    International Nuclear Information System (INIS)

    Hettelingh, J.P.

    1993-01-01

    Critical loads for acidity, sulphur and nitrogen have been computed and geographically mapped in Europe. Critical loads are compared to actual deposition of acidity and of sulphur. Results show that parts of central and north-west Europe receive 20 times or more acidity than the ecosystems' critical loads, thus affecting the long-term sustainability. The Regional Acidification INformation and Simulation model (RAINS) is used to assess 2 scenarios of emission reduction. The first scenario describes currently applied reductions whereas the second assesses the application of maximum feasible reductions to SO 2 and NO x . The latter scenario significantly reduces the area of Europe where critical loads are exceeded. In general, it is shown that a pan-european policy is of highest necessity for obtaining an efficient reduction of acidic emissions throughout Europe. For France, in particular, it is concluded that the excess of critical loads for acidity is largely due to ammonia

  8. Machine Learning of the Reactor Core Loading Pattern Critical Parameters

    Directory of Open Access Journals (Sweden)

    Krešimir Trontl

    2008-01-01

    Full Text Available The usual approach to loading pattern optimization involves high degree of engineering judgment, a set of heuristic rules, an optimization algorithm, and a computer code used for evaluating proposed loading patterns. The speed of the optimization process is highly dependent on the computer code used for the evaluation. In this paper, we investigate the applicability of a machine learning model which could be used for fast loading pattern evaluation. We employ a recently introduced machine learning technique, support vector regression (SVR, which is a data driven, kernel based, nonlinear modeling paradigm, in which model parameters are automatically determined by solving a quadratic optimization problem. The main objective of the work reported in this paper was to evaluate the possibility of applying SVR method for reactor core loading pattern modeling. We illustrate the performance of the solution and discuss its applicability, that is, complexity, speed, and accuracy.

  9. Machine Learning of the Reactor Core Loading Pattern Critical Parameters

    International Nuclear Information System (INIS)

    Trontl, K.; Pevec, D.; Smuc, T.

    2008-01-01

    The usual approach to loading pattern optimization involves high degree of engineering judgment, a set of heuristic rules, an optimization algorithm, and a computer code used for evaluating proposed loading patterns. The speed of the optimization process is highly dependent on the computer code used for the evaluation. In this paper, we investigate the applicability of a machine learning model which could be used for fast loading pattern evaluation. We employ a recently introduced machine learning technique, support vector regression (SVR), which is a data driven, kernel based, nonlinear modeling paradigm, in which model parameters are automatically determined by solving a quadratic optimization problem. The main objective of the work reported in this paper was to evaluate the possibility of applying SVR method for reactor core loading pattern modeling. We illustrate the performance of the solution and discuss its applicability, that is, complexity, speed, and accuracy

  10. [Mapping Critical Loads of Heavy Metals for Soil Based on Different Environmental Effects].

    Science.gov (United States)

    Shi, Ya-xing; Wu, Shao-hua; Zhou, Sheng-lu; Wang, Chun-hui; Chen, Hao

    2015-12-01

    China's rapid development of industrialization and urbanization causes the growing problem of heavy metal pollution of soil, threatening environment and human health. Therefore, prevention and management of heavy metal pollution become particularly important. Critical loads of heavy metals are an important management tool that can be utilized to prevent the occurrence of heavy metal pollution. Our study was based on three cases: status balance, water environmental effects and health risks. We used the steady-state mass balance equation to calculate the critical loads of Cd, Cu, Pb, Zn at different effect levels and analyze the values and spatial variation of critical loads. In addition, we used the annual input fluxes of heavy metals of the agro-ecosystem in the Yangtze River delta and China to estimate the proportion of area with exceedance of critical loads. The results demonstrated that the critical load value of Cd was the minimum, and the values of Cu and Zn were lager. There were spatial differences among the critical loads of four elements in the study area, lower critical loads areas mainly occurred in woodland and high value areas distributed in the east and southwest of the study area, while median values and the medium high areas mainly occurred in farmland. Comparing the input fluxes of heavy metals, we found that Pb and Zn in more than 90% of the area exceeded the critical loads under different environmental effects in the study area. The critical load exceedance of Cd mainly occurred under the status balance and the water environmental effect, while Cu under the status balance and water environmental effect with a higher proportion of exceeded areas. Critical loads of heavy metals at different effect levels in this study could serve as a reference from effective control of the emissions of heavy metals and to prevent the occurrence of heavy metal pollution.

  11. Machine learning of the reactor core loading pattern critical parameters

    International Nuclear Information System (INIS)

    Trontl, K.; Pevec, D.; Smuc, T.

    2007-01-01

    The usual approach to loading pattern optimization involves high degree of engineering judgment, a set of heuristic rules, an optimization algorithm and a computer code used for evaluating proposed loading patterns. The speed of the optimization process is highly dependent on the computer code used for the evaluation. In this paper we investigate the applicability of a machine learning model which could be used for fast loading pattern evaluation. We employed a recently introduced machine learning technique, Support Vector Regression (SVR), which has a strong theoretical background in statistical learning theory. Superior empirical performance of the method has been reported on difficult regression problems in different fields of science and technology. SVR is a data driven, kernel based, nonlinear modelling paradigm, in which model parameters are automatically determined by solving a quadratic optimization problem. The main objective of the work reported in this paper was to evaluate the possibility of applying SVR method for reactor core loading pattern modelling. The starting set of experimental data for training and testing of the machine learning algorithm was obtained using a two-dimensional diffusion theory reactor physics computer code. We illustrate the performance of the solution and discuss its applicability, i.e., complexity, speed and accuracy, with a projection to a more realistic scenario involving machine learning from the results of more accurate and time consuming three-dimensional core modelling code. (author)

  12. Critical loads of nitrogen deposition and critical levels of atmospheric ammonia for semi-natural Mediterranean evergreen woodlands

    Directory of Open Access Journals (Sweden)

    P. Pinho

    2012-03-01

    Full Text Available Nitrogen (N has emerged in recent years as a key factor associated with global changes, with impacts on biodiversity, ecosystems functioning and human health. In order to ameliorate the effects of excessive N, safety thresholds such as critical loads (deposition fluxes and levels (concentrations can be established. Few studies have assessed these thresholds for semi-natural Mediterranean ecosystems. Our objective was therefore to determine the critical loads of N deposition and long-term critical levels of atmospheric ammonia for semi-natural Mediterranean evergreen woodlands. We have considered changes in epiphytic lichen communities, one of the most sensitive comunity indicators of excessive N in the atmosphere. Based on a classification of lichen species according to their tolerance to N we grouped species into response functional groups, which we used as a tool to determine the critical loads and levels. This was done for a Mediterranean climate in evergreen cork-oak woodlands, based on the relation between lichen functional diversity and modelled N deposition for critical loads and measured annual atmospheric ammonia concentrations for critical levels, evaluated downwind from a reduced N source (a cattle barn. Modelling the highly significant relationship between lichen functional groups and annual atmospheric ammonia concentration showed the critical level to be below 1.9 μg m−3, in agreement with recent studies for other ecosystems. Modelling the highly significant relationship between lichen functional groups and N deposition showed that the critical load was lower than 26 kg (N ha−1 yr−1, which is within the upper range established for other semi-natural ecosystems. Taking into account the high sensitivity of lichen communities to excessive N, these values should aid development of policies to protect Mediterranean woodlands from the initial effects of excessive N.

  13. The asymptotic variance of departures in critically loaded queues

    NARCIS (Netherlands)

    Al Hanbali, Ahmad; Mandjes, M.R.H.; Nazarathy, Y.; Whitt, W.

    2011-01-01

    We consider the asymptotic variance of the departure counting process D(t) of the GI/G/1 queue; D(t) denotes the number of departures up to time t. We focus on the case where the system load ϱ equals 1, and prove that the asymptotic variance rate satisfies limt→∞varD(t) / t = λ(1 - 2 / π)(ca2 +

  14. Determination of the critical plane and durability estimation for a multiaxial cyclic loading

    Science.gov (United States)

    Burago, N. G.; Nikitin, A. D.; Nikitin, I. S.; Yakushev, V. L.

    2018-03-01

    An analytical procedure is proposed to determine the critical plane orientation according to the Findley criterion for the multiaxial cyclic loading. The cases of in-phase and anti-phase cyclic loading are considered. Calculations of the stress state are carried out for the system of the gas turbine engine compressor disk and blades for flight loading cycles. The formulas obtained are used for estimations of the fatigue durability of this essential element of structure.

  15. Mapping critical levels/loads for the Slovak Republic. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Zavodsky, D; Babiakova, G; Mitosinkova, M [and others

    1996-08-01

    As a part of the Agreement on Environmental Cooperation between Norway and Slovakia a project ``Mapping Critical Levels/Loads for Slovakia`` was established. This report presents the final project results. Critical loads for forest, surface and ground waters and their exceedances were calculated by means of the steady-state mass balance model PROFILE for soils, and the steady-state water chemistry method for waters. A grid distance of 10 km was used. Because the sulphur deposition has been decreasing, the exceedances of critical load of acidity and critical sulphur deposition of forest soils have decreased from 1990 to 1995. Practically no acidity exceedances for surface water or ground water were found in 1995. The critical level of forest ozone was exceeded all over Slovakia. In the Tatra mountains the exceedance was over 25000 ppb.h. 23 refs., 3 figs., 3 tabs.

  16. Microgrids for Service Restoration to Critical Load in a Resilient Distribution System

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yin; Liu, Chen-Ching; Schneider, Kevin P.; Tuffner, Francis K.; Ton, Dan T.

    2018-01-01

    icrogrids can act as emergency sources to serve critical loads when utility power is unavailable. This paper proposes a resiliency-based methodology that uses microgrids to restore critical loads on distribution feeders after a major disaster. Due to limited capacity of distributed generators (DGs) within microgrids, dynamic performance of the DGs during the restoration process becomes essential. In this paper, the stability of microgrids, limits on frequency deviation, and limits on transient voltage and current of DGs are incorporated as constraints of the critical load restoration problem. The limits on the amount of generation resources within microgrids are also considered. By introducing the concepts of restoration tree and load group, restoration of critical loads is transformed into a maximum coverage problem, which is a linear integer program (LIP). The restoration paths and actions are determined for critical loads by solving the LIP. A 4-feeder, 1069-bus unbalanced test system with four microgrids is utilized to demonstrate the effectiveness of the proposed method. The method is applied to the distribution system in Pullman, WA, resulting in a strategy that uses generators on the Washington State University campus to restore service to the Hospital and City Hall in Pullman.

  17. Air pollution and impact on eco-systems. Load concept/critical level and its consequences

    International Nuclear Information System (INIS)

    Elichegaray, C.

    1993-01-01

    Critical loads and critical levels respectively can be defined as the deposition value, or the concentration of pollutants in the atmosphere, above which adverse effects on receptors such as plants, ecosystems, materials may occur. Important research is currently being developed on critical loads and levels in the framework of the Geneva convention on transboundary air pollution. Several binding protocols have been elaborated between the european countries, the Canada, and the USA, to reduce their emissions of sulphur, nitrogen oxides, volatile organic compounds. This article describes the critical loads and levels approach, and the way by which this concept is now used for the revision of the sulphur protocol. (author). 6 refs., 5 figs., 4 tabs

  18. Steady-state critical loads of acidity for forest soils in the Georgia Basin, British Columbia

    Directory of Open Access Journals (Sweden)

    Shaun A. WATMOUGH

    2010-08-01

    Full Text Available There has been growing interest in acid rain research in western Canada where sulphur (S and nitrogen (N emissions are expected to increase during the next two decades. One region of concern is southern British Columbia, specifically the Georgia Basin, where emissions are expected to increase owing to the expansion of industry and urban centres (Vancouver and Victoria. In the current study, weathering rates and critical loads of acidity (S and N for forest soils were estimated at nineteen sites located within the Georgia Basin. A base cation to aluminium ratio of 10 was selected as the critical chemical criterion associated with ecosystem damage. The majority of the sites (58% had low base cation weathering rates (≤50 meq m–2 y–1 based on the PROFILE model. Accordingly, mean critical load for the study sites, estimated using the steady-state mass balance model, ranged between 129–168 meq m–2 y–1. Annual average total (wet and dry S and N deposition during the period 2005–2006 (estimated by the Community Multiscale Air Quality model, exceeded critical load at five–nine of the study sites (mean exceedance = 32–46 meq m–2 y–1. The high-elevation (>1000 m study sites had shallow, acid sensitive, soils with low weathering rates; however, critical loads were predominantly exceeded at sites close to Vancouver under higher modelled deposition loads. The extent of exceedance is similar to other industrial regions in western and eastern Canada.

  19. The scratch test - Different critical load determination techniques. [adhesive strength of thin hard coatings

    Science.gov (United States)

    Sekler, J.; Hintermann, H. E.; Steinmann, P. A.

    1988-01-01

    Different critical load determination techniques such as microscopy, acoustic emission, normal, tangential, and lateral forces used for scratch test evaluation of complex or multilayer coatings are investigated. The applicability of the scratch test to newly developed coating techniques, systems, and applications is discussed. Among the methods based on the use of a physical measurement, acoustic emission detection is the most effective. The dynamics ratio between the signals below and above the critical load for the acoustic emission (much greater than 100) is well above that obtained with the normal, tangential, and lateral forces. The present commercial instruments are limited in load application performance. A scratch tester able to apply accurate loads as low as 0.01 N would probably overcome most of the actual limitations and would be expected to extend the scratch testing technique to different application fields such as optics and microelectronics.

  20. Derivation and Mapping of Critical Loads for Nitrogen and Trends in Their Exceedance in Germany

    Directory of Open Access Journals (Sweden)

    Hans-Dieter Nagel

    2001-01-01

    Full Text Available The term “critical load” means a quantitative estimate of an exposure to one or more pollutants below which significant harmful effects on specified sensitive elements of the environment do not occur, according to present knowledge. In the case of nitrogen, both oxidised and reduced compounds contribute to the total deposition of acidity, which exceeds critical loads in many forest ecosystems. These also cause negative effects through eutrophication. Critical loads of nitrogen were derived for forest soils (deciduous and coniferous forest, natural grassland, acid fens, heathland, and mesotrophic peat bogs. In Germany, a decrease in sulphur emissions over the past 15 years resulted in a reduced exceedance of critical loads for acid deposition. In the same period it was noted that reduction in the emissions of nitrogen oxides and ammonia remained insignificant. Therefore, emissions of nitrogen compounds have become relatively more important and will continue to threaten ecosystem function and stability. The risk of environmental damage remains at an unacceptable level. The German maps show the degree to which the critical loads are exceeded, and they present current developments and an expected future trend. Results indicate that recovery from pollutant stress occurs only gradually.

  1. Water pollution abatement programme. The Czech Republic. Project 4.2. Assessing critical loads of acidity to surface waters in the Czech Republic. Critical loads of acidity to surface waters, north-eastern Bohemia and northern Moravia, The Czech Republic

    Energy Technology Data Exchange (ETDEWEB)

    Lien, L.; Raclavsky, K.; Raclavska, H.; Matysek, D.; Hovind, H.

    1996-01-01

    This report discusses estimates of critical loads of acidity to surface waters and their exceedances, for north-eastern Bohemia and Moravia in The Czech Republic. The survey covers 13 400 km{sup 2}, or 17% of the area of the country. Varying critical loads were observed within the examined region. 19% of the examined area showed exceedance of critical load and another 11% was close to exceedance. The survey should continue in Bohemia. 24 refs., 20 figs., 4 tabs.

  2. Evaluation of cognitive load and emotional states during multidisciplinary critical care simulation sessions.

    Science.gov (United States)

    Pawar, Swapnil; Jacques, Theresa; Deshpande, Kush; Pusapati, Raju; Meguerdichian, Michael J

    2018-04-01

    The simulation in critical care setting involves a heterogeneous group of participants with varied background and experience. Measuring the impacts of simulation on emotional state and cognitive load in this setting is not often performed. The feasibility of such measurement in the critical care setting needs further exploration. Medical and nursing staff with varying levels of experience from a tertiary intensive care unit participated in a standardised clinical simulation scenario. The emotional state of each participant was assessed before and after completion of the scenario using a validated eight-item scale containing bipolar oppositional descriptors of emotion. The cognitive load of each participant was assessed after the completion of the scenario using a validated subjective rating tool. A total of 103 medical and nursing staff participated in the study. The participants felt more relaxed (-0.28±1.15 vs 0.14±1, Pcognitive load for all participants was 6.67±1.41. There was no significant difference in the cognitive loads among medical staff versus nursing staff (6.61±2.3 vs 6.62±1.7; P>0.05). A well-designed complex high fidelity critical care simulation scenario can be evaluated to identify the relative cognitive load of the participants' experience and their emotional state. The movement of learners emotionally from a more negative state to a positive state suggests that simulation can be an effective tool for improved knowledge transfer and offers more opportunity for dynamic thinking.

  3. Effect of ventilation rate and board loading on formaldehyde concentration : a critical review of the literature

    Science.gov (United States)

    George E. Myers

    1984-01-01

    A critical literature review has been carried out on the influence of ventilation rate (N, hr.-1) and board loading (L, m2/m3) on steady state formaldehyde concentrations (Cs, ppm) resulting from particleboard and plywood emissions. Large differences exist among boards in the extent to which their formaldehyde concentrations change with N or L in laboratory chambers....

  4. Estimation of critical loads for radiocaesium in Fennoscandia and Northwest Russia

    International Nuclear Information System (INIS)

    Howard, B.J.; Wright, S.M.; Barnett, C.L.; Skuterud, L.; Strand, P.

    2002-01-01

    The application of the critical loads methodology for radioactive contamination of Arctic and sub-arctic ecosystems, where natural and semi-natural food products are important components of the diet of many people, is proposed and discussed. The critical load is herein defined as the amount of radionuclide deposition necessary to produce radionuclide activity concentrations in food products exceeding intervention limits. The high transfer of radiocaesium to reindeer meat gives this product the lowest critical load, even though the intervention limit is relatively high compared with other products. Ecological half-lives of radiocaesium in natural and semi-natural products are often very long, and it is therefore important to take account of contamination already present in the event of an accident affecting areas where such products are important. In particular, the long ecological half-life for radiocaesium in moose meat means that the critical load is highly sensitive to prior deposition. An example of the potential application of the method for emergency preparedness is given for the Chernobyl accident

  5. Airborne pollutants. Transports, effects and critical loads; Lufttransporterte forurensninger. Tilfoersler, virkninger og taalegrenser

    Energy Technology Data Exchange (ETDEWEB)

    Floeysand, I; Loebersli, E [eds.

    1996-01-01

    The report from a conference concerns two Norwegian research programmes. The first one deals with the transports and effects of airborne pollutants, and the second one relates to the critical loads of nature. A number of 17 papers from the conference are prepared. 318 refs., 57 figs., 22 tabs.

  6. Preliminary modelling and mapping of critical loads for cadmium and lead in Europa

    NARCIS (Netherlands)

    Hettelingh JP; Slootweg J; Posch M; Ilyin I; MNV-CCE/WGE-IPC M&M Coordination Center for Effects; EMEP-Meteorological Synthesizing Centre-East

    2004-01-01

    De "Working Group on Effects" (WGE) van de "Convention on Long-range Transboundary Air Pollution" onder de "United Nations Economic Commission or Europe" (UNECE-CLRTAP) heeft tijdens haar 20e bijeenkomst besloten dat de methode om kritische depositiewaarden (critical loads) voor cadmium en lood in

  7. Updated assessment of critical loads of lead and cadmium for European forest soils

    NARCIS (Netherlands)

    Reinds, G.J.; Vries, de W.; Groenenberg, J.E.

    2002-01-01

    At its 20th session the Working Group on Effects (WGE) of the Convention on Long-range Transboundary Air Pollution of the United Nations Economic Commission for Europe (UNECECLRTAP), noted the need to further develop and test the methodology for mapping critical loads for cadmium and lead. To this

  8. Lichen-based critical loads for atmospheric nitrogen deposition in Western Oregon and Washington forests, USA

    Science.gov (United States)

    Linda H. Geiser; Sarah E. Jovan; Doug A. Glavich; Matthew K. Porter

    2010-01-01

    Critical loads (CLs) define maximum atmospheric deposition levels apparently preventative of ecosystem harm. We present first nitrogen CLs for northwestern North America's maritime forests. Using multiple linear regression, we related epiphytic-macrolichen community composition to: 1) wet deposition from the National Atmospheric Deposition Program, 2) wet, dry,...

  9. Application of static critical load models for acidity to high mountain lakes in Europe

    Czech Academy of Sciences Publication Activity Database

    Curtis, C. J.; Barbieri, A.; Camarero, L.; Gabathuler, M.; Galas, J.; Hanselmann, K.; Kopáček, Jiří; Mosello, R.; Nickus, U.; Rose, N.; Stuchlík, E.; Thies, H.; Ventura, M.; Wright, R.

    2002-01-01

    Roč. 2, č. 2 (2002), s. 115-126 ISSN 1567-7230 Grant - others:EU(XE) MOLAR ENV4-CT95-0007; EU(XE) Environment and Climate Programme Keywords : acid deposition * critical loads Subject RIV: DJ - Water Pollution ; Quality

  10. Effects of nitrogen deposition and empirical nitrogen critical loads for ecoregions of the United States

    Science.gov (United States)

    Pardo, L.H.; Fenn, M.E.; Goodale, C.L.; Geiser, L.H.; Driscoll, C.T.; Allen, E.B.; Baron, Jill S.; Bobbink, R.; Bowman, W.D.; Clark, C.M.; Emmett, B.; Gilliam, F.S.; Greaver, T.L.; Hall, S.J.; Lilleskov, E.A.; Liu, L.; Lynch, J.A.; Nadelhoffer, K.J.; Perakis, S.S.; Robin-Abbott, M. J.; Stoddard, J.L.; Weathers, K.C.; Dennis, R.L.

    2011-01-01

    Human activity in the last century has led to a significant increase in nitrogen (N) emissions and atmospheric deposition. This N deposition has reached a level that has caused or is likely to cause alterations to the structure and function of many ecosystems across the United States. One approach for quantifying the deposition of pollution that would be harmful to ecosystems is the determination of critical loads. A critical load is defined as the input of a pollutant below which no detrimental ecological effects occur over the long-term according to present knowledge. The objectives of this project were to synthesize current research relating atmospheric N deposition to effects on terrestrial and freshwater ecosystems in the United States, and to estimate associated empirical N critical loads. The receptors considered included freshwater diatoms, mycorrhizal fungi, lichens, bryophytes, herbaceous plants, shrubs, and trees. Ecosystem impacts included: (1) biogeochemical responses and (2) individual species, population, and community responses. Biogeochemical responses included increased N mineralization and nitrification (and N availability for plant and microbial uptake), increased gaseous N losses (ammonia volatilization, nitric and nitrous oxide from nitrification and denitrification), and increased N leaching. Individual species, population, and community responses included increased tissue N, physiological and nutrient imbalances, increased growth, altered root : shoot ratios, increased susceptibility to secondary stresses, altered fire regime, shifts in competitive interactions and community composition, changes in species richness and other measures of biodiversity, and increases in invasive species. The range of critical loads for nutrient N reported for U.S. ecoregions, inland surface waters, and freshwater wetlands is 1-39 kg N.ha -1.yr -1, spanning the range of N deposition observed over most of the country. The empirical critical loads for N tend to

  11. Mapping critical loads of nitrogen deposition for aquatic ecosystems in the Rocky Mountains, USA

    International Nuclear Information System (INIS)

    Nanus, Leora; Clow, David W.; Saros, Jasmine E.; Stephens, Verlin C.; Campbell, Donald H.

    2012-01-01

    Spatially explicit estimates of critical loads of nitrogen (N) deposition (CL Ndep ) for nutrient enrichment in aquatic ecosystems were developed for the Rocky Mountains, USA, using a geostatistical approach. The lowest CL Ndep estimates ( −1 yr −1 ) occurred in high-elevation basins with steep slopes, sparse vegetation, and abundance of exposed bedrock and talus. These areas often correspond with areas of high N deposition (>3 kg N ha −1 yr −1 ), resulting in CL Ndep exceedances ≥1.5 ± 1 kg N ha −1 yr −1 . CL Ndep and CL Ndep exceedances exhibit substantial spatial variability related to basin characteristics and are highly sensitive to the NO 3 − threshold at which ecological effects are thought to occur. Based on an NO 3 − threshold of 0.5 μmol L −1 , N deposition exceeds CL Ndep in 21 ± 8% of the study area; thus, broad areas of the Rocky Mountains may be impacted by excess N deposition, with greatest impacts at high elevations. - Highlights: ► Critical loads maps for nutrient enrichment effects of nitrogen deposition. ► Critical load estimates show spatial variability related to basin characteristics. ► Critical loads are sensitive to the nitrate threshold value for ecological effects. ► Broad areas of the Rocky Mountains may be impacted by excess nitrogen deposition. - Critical loads maps for nutrient enrichment effects of nitrogen deposition show that broad areas of the Rocky Mountains may be impacted by excess nitrogen deposition.

  12. The impact of occupational load carriage on carrier mobility: a critical review of the literature.

    Science.gov (United States)

    Carlton, Simon D; Orr, Robin M

    2014-01-01

    Military personnel and firefighters are required to carry occupational loads and complete tasks in hostile and unpredictable environments where a lack of mobility may risk lives. This review critically examines the literature investigating the impacts of load carriage on the mobility of these specialist personnel. Several literature databases, reference lists, and subject matter experts were employed to identify relevant studies. Studies meeting the inclusion criteria were critiqued using the Downs and Black protocol. Inter-rater agreement was determined by Cohen's κ. Twelve original research studies, which included male and female participants from military and firefighting occupations, were critiqued (κ = .81). A review of these papers found that as the carried load weight increased, carrier mobility during aerobic tasks (like road marching) and anaerobic tasks (like obstacle course negotiation) decreased. As such, it can be concluded that the load carried by some specialist personnel may increase their occupational risk by reducing their mobility.

  13. Power Generation by Zinc Antimonide Thin Film under Various Load Resistances at its Critical Operating Temperature

    DEFF Research Database (Denmark)

    Mir Hosseini, Seyed Mojtaba; Rezaniakolaei, Alireza; Rosendahl, Lasse Aistrup

    slightly reduces during unload conditions, although it is expected that by eliminating load in each step, the initial amount of voltage exactly repeats. Similar behavior is observed for Seebeck coefficient distribution versus time of working particularly in lower load resistances. Based on variation...... thin films operating under different load resistances at around its critical operating temperature, 400 ᵒC. The thermoelement is subjected to constant hot side temperature and to room temperature at the cold junction in order to measure the thin film TEG’s sample performance. The nominal loads equal...... to 10, 15, 20, 25, 30, 35, 40, 45… 175, and also 200 Ohms were applied. The results show that the value of the Seebeck coefficient is 0.0002 [V/K] for the specimen, which is in agreement with quantities of other zinc antimonide bulks materials in literature. The results also show that the voltage...

  14. Identification of critical equipment and determination of operational limits in helium refrigerators under pulsed heat load

    Science.gov (United States)

    Dutta, Rohan; Ghosh, Parthasarathi; Chowdhury, Kanchan

    2014-01-01

    Large-scale helium refrigerators are subjected to pulsed heat load from tokamaks. As these plants are designed for constant heat loads, operation under such varying load may lead to instability in plants thereby tripping the operation of different equipment. To understand the behavior of the plant subjected to pulsed heat load, an existing plant of 120 W at 4.2 K and another large-scale plant of 18 kW at 4.2 K have been analyzed using a commercial process simulator Aspen Hysys®. A similar heat load characteristic has been applied in both quasi steady state and dynamic analysis to determine critical stages and equipment of these plants from operational point of view. It has been found that the coldest part of both the cycles consisting JT-stage and its preceding reverse Brayton stage are the most affected stages of the cycles. Further analysis of the above stages and constituting equipment revealed limits of operation with respect to variation of return stream flow rate resulted from such heat load variations. The observations on the outcome of the analysis can be used for devising techniques for steady operation of the plants subjected to pulsed heat load.

  15. A conceptual framework: Redefining forest soil's critical acid loads under a changing climate

    International Nuclear Information System (INIS)

    McNulty, Steven G.; Boggs, Johnny L.

    2010-01-01

    Federal agencies of several nations have or are currently developing guidelines for critical forest soil acid loads. These guidelines are used to establish regulations designed to maintain atmospheric acid inputs below levels shown to damage forests and streams. Traditionally, when the critical soil acid load exceeds the amount of acid that the ecosystem can absorb, it is believed to potentially impair forest health. The excess over the critical soil acid load is termed the exceedance, and the larger the exceedance, the greater the risk of ecosystem damage. This definition of critical soil acid load applies to exposure of the soil to a single, long-term pollutant (i.e., acidic deposition). However, ecosystems can be simultaneously under multiple ecosystem stresses and a single critical soil acid load level may not accurately reflect ecosystem health risk when subjected to multiple, episodic environmental stress. For example, the Appalachian Mountains of western North Carolina receive some of the highest rates of acidic deposition in the eastern United States, but these levels are considered to be below the critical acid load (CAL) that would cause forest damage. However, the area experienced a moderate three-year drought from 1999 to 2002, and in 2001 red spruce (Picea rubens Sarg.) trees in the area began to die in large numbers. The initial survey indicated that the affected trees were killed by the southern pine beetle (Dendroctonus frontalis Zimm.). This insect is not normally successful at colonizing these tree species because the trees produce large amounts of oleoresin that exclude the boring beetles. Subsequent investigations revealed that long-term acid deposition may have altered red spruce forest structure and function. There is some evidence that elevated acid deposition (particularly nitrogen) reduced tree water uptake potential, oleoresin production, and caused the trees to become more susceptible to insect colonization during the drought period

  16. Critical current degradation in superconducting niobium-titanium alloys in external magnetic fields under loading

    International Nuclear Information System (INIS)

    Bojko, V.S.; Lazareva, M.B.; Starodubov, Ya.D.; Chernyj, O.V.; Gorbatenko, V.M.

    1992-01-01

    The effect of external magnetic fields on the stress at which the critical current starts to degrade (the degradation threshold σ 0 e ) under mechanical loads in superconducting Nb-Ti alloys is studied and a possible mechanism of realization of the effect observed is proposed.It is assumed that additional stresses on the transformation dislocation from the external magnetic fields are beneficial for the growth of martensite inclusions whose superconducting parameters (critical current density j k and critical temperature T k ) are lower then those in the initial material.The degradation threshold is studied experimentally in external magnetic fields H up to 7 T.The linear dependence σ 0 e (H) is observed.It is shown that external magnetic fields play an important role in the critical current degradation at the starting stages of deformation.This fact supports the assumption that the degradation of superconducting parameters under loading are due to the phenomenon of superelasticity,i.e. a reversible load-induced change in the martensite inclusions sizes rather than the reversible mechanical twinning.The results obtained are thought to be important to estimating superconducting solenoid stability in a wide range of magnetic fields

  17. New approaches to provide ride-through for critical loads in electric power distribution systems

    Science.gov (United States)

    Montero-Hernandez, Oscar C.

    2001-07-01

    The extensive use of electronic circuits has enabled modernization, automation, miniaturization, high quality, low cost, and other achievements regarding electric loads in the last decades. However, modern electronic circuits and systems are extremely sensitive to disturbances from the electric power supply. In fact, the rate at which these disturbances happen is considerable as has been documented in recent years. In response to the power quality concerns presented previously, this dissertation is proposing new approaches to provide ride-through for critical loads during voltage disturbances with emphasis on voltage sags. In this dissertation, a new approach based on an AC-DC-AC system is proposed to provide ride-through for critical loads connected in buildings and/or an industrial system. In this approach, a three-phase IGBT inverter with a built in Dc-link voltage regulator is suitably controlled along with static by-pass switches to provide continuous power to critical loads. During a disturbance, the input utility source is disconnected and the power from the inverter is connected to the load. The remaining voltage in the AC supply is converted to DC and compensated before being applied to the inverter and the load. After detecting normal utility conditions, power from the utility is restored to the critical load. In order to achieve an extended ride-through capability a second approach is introduced. In this case, the Dc-link voltage regulator is performed by a DC-DC Buck-Boost converter. This new approach has the capability to mitigate voltage variations below and above the nominal value. In the third approach presented in this dissertation, a three-phase AC to AC boost converter is investigated. This converter provides a boosting action for the utility input voltages, right before they are applied to the load. The proposed Pulse Width Modulation (PWM) control strategy ensures independent control of each phase and compensates for both single-phase or poly

  18. A novel reformulation of the Theory of Critical Distances to design notched metals against dynamic loading

    International Nuclear Information System (INIS)

    Yin, T.; Tyas, A.; Plekhov, O.; Terekhina, A.; Susmel, L.

    2015-01-01

    Highlights: • The proposed method is successful in estimating dynamic strength of metals. • The critical distance varies as the loading/strain/displacement rate increases. • The reference strength varies as the loading/strain/displacement rate increases. • This method is recommended to be used with safety factors larger than 1.25. - Abstract: In the present study the linear-elastic Theory of Critical Distances (TCD) is reformulated to make it suitable for predicting the strength of notched metallic materials subjected to dynamic loading. The accuracy and reliability of the proposed reformulation of the TCD was checked against a number of experimental results generated by testing, under different loading/strain rates, notched cylindrical samples of aluminium alloy 6063-T5, titanium alloy Ti–6Al–4V, aluminium alloy AlMg6, and an AlMn alloy. To further validate the proposed design method also different data sets taken from the literature were considered. Such an extensive validation exercise allowed us to prove that the proposed reformulation of the TCD is successful in predicting the dynamic strength of notched metallic materials, this approach proving to be capable of estimates falling within an error interval of ±20%. Such a high level of accuracy is certainly remarkable, especially in light of the fact that it was reached without the need for explicitly modelling the stress vs. strain dynamic behaviour of the investigated ductile metals

  19. Vegetation community change points suggest that critical loads of nutrient nitrogen may be too high

    Science.gov (United States)

    Wilkins, Kayla; Aherne, Julian; Bleasdale, Andy

    2016-12-01

    It is widely accepted that elevated nitrogen deposition can have detrimental effects on semi-natural ecosystems, including changes to plant diversity. Empirical critical loads of nutrient nitrogen have been recommended to protect many sensitive European habitats from significant harmful effects. In this study, we used Threshold Indicator Taxa Analysis (TITAN) to investigate shifts in vegetation communities along an atmospheric nitrogen deposition gradient for twenty-two semi-natural habitat types (as described under Annex I of the European Union Habitats Directive) in Ireland. Significant changes in vegetation community, i.e., change points, were determined for twelve habitats, with seven habitats showing a decrease in the number of positive indicator species. Community-level change points indicated a decrease in species abundance along a nitrogen deposition gradient ranging from 3.9 to 15.3 kg N ha-1 yr-1, which were significantly lower than recommended critical loads (Wilcoxon signed-rank test; V = 6, p < 0.05). These results suggest that lower critical loads of empirical nutrient nitrogen deposition may be required to protect many European habitats. Changes to vegetation communities may mean a loss of sensitive indicator species and potentially rare species in these habitats, highlighting how emission reductions policies set under the National Emissions Ceilings Directive may be directly linked to meeting the goal set out under the European Union's Biodiversity Strategy of "halting the loss of biodiversity" across Europe by 2020.

  20. Effects and empirical critical loads of Nitrogen for ecoregions of the United States

    Science.gov (United States)

    Pardo, Linda H.; Robin-Abbott, Molly J.; Fenn, Mark E.; Goodale, Christine L.; Geiser, Linda H.; Driscoll, Charles T.; Allen, Edith B.; Baron, Jill S.; Bobbink, Roland; Bowman, William D.; Clark, C M; Emmett, B.; Gilliam, Frank S; Greaver, Tara L.; Hall, Sharon J; Lilleskov, Erik A.; Liu, Lingli; Lynch, Jason A.; Nadelhoffer, Knute J; Perakis, Steven; Stoddard, John L; Weathers, Kathleen C.; Dennis, Robin L.

    2015-01-01

    Human activity in the last century has increased nitrogen (N) deposition to a level that has caused or is likely to cause alterations to the structure and function of many ecosystems across the United States. We synthesized current research relating atmospheric N deposition to effects on terrestrial and freshwater ecosystems in the United States, and estimated associated empirical critical loads of N for several receptors: freshwater diatoms, mycorrhizal fungi, lichens, bryophytes, herbaceous plants, shrubs, and trees. Biogeochemical responses included increased N mineralization and nitrification, increased gaseous N losses, and increased N leaching. Individual species, population, and community responses included increased tissue N, physiological and nutrient imbalances, increased growth, altered root-shoot ratios, increased susceptibility to secondary stresses, altered fire regime, shifts in competitive interactions and community composition, changes in species richness and other measures of biodiversity, and increases in invasive species. The range of critical loads of nutrient N reported for U.S. ecoregions, inland surface waters, and freshwater wetlands is 1–39 kg N ha−1 yr−1, spanning the range of N deposition observed over most of the country. The empirical critical loads of N tend to increase in the following sequence: diatoms, lichens and bryophytes, mycorrhizal fungi, herbaceous plants and shrubs, trees.

  1. Surface water acidification and critical loads: exploring the F-factor

    Directory of Open Access Journals (Sweden)

    K. Bishop

    2009-11-01

    Full Text Available As acid deposition decreases, uncertainties in methods for calculating critical loads become more important when judgements have to be made about whether or not further emission reductions are needed. An important aspect of one type of model that has been used to calculate surface water critical loads is the empirical F-factor which estimates the degree to which acid deposition is neutralised before it reaches a lake at any particular point in time relative to the pre-industrial, steady-state water chemistry conditions.

    In this paper we will examine how well the empirical F-functions are able to estimate pre-industrial lake chemistry as lake chemistry changes during different phases of acidification and recovery. To accomplish this, we use the dynamic, process-oriented biogeochemical model SAFE to generate a plausible time series of annual runoff chemistry for ca. 140 Swedish catchments between 1800 and 2100. These annual hydrochemistry data are then used to generate empirical F-factors that are compared to the "actual" F-factor seen in the SAFE data for each lake and year in the time series. The dynamics of the F-factor as catchments acidify, and then recover are not widely recognised.

    Our results suggest that the F-factor approach worked best during the acidification phase when soil processes buffer incoming acidity. However, the empirical functions for estimating F from contemporary lake chemistry are not well suited to the recovery phase when the F-factor turns negative due to recovery processes in the soil. This happens when acid deposition has depleted the soil store of BC, and then acid deposition declines, reducing the leaching of base cations to levels below those in the pre-industrial era. An estimate of critical load from water chemistry during recovery and empirical F functions would therefore result in critical loads that are too low. Therefore, the empirical estimates of the F-factor are a significant source of

  2. The development of an approach to assess critical loads of acidity for woodland habitats in Great Britain

    Directory of Open Access Journals (Sweden)

    S. J. Langan

    2004-01-01

    Full Text Available Alongside other countries that are signatories to the UNECE Convention Long Range Transboundary on Air Pollution, the UK is committed to reducing the impact of air pollution on the environment. To advise and guide this policy in relation to atmospheric emissions of sulphur and nitrogen, a critical load approach has been developed. To assess the potential impact of these pollutants on woodland habitats a steady state, simple mass balance model has been parameterised. For mineral soils, a Ca:Al ratio in soil solution has been used as the critical load indicator for potential damage. For peat and organic soils critical loads have been set according to a pH criterion. Together these approaches have been used with national datasets to examine the potential scale of acidification in woodland habitats across the UK. The results can be mapped to show the spatial variability in critical loads of the three principal woodland habitat types (managed coniferous, managed broadleaved/ mixed woodland and unmanaged woodland. The results suggest that there is a wide range of critical loads. The most sensitive (lowest critical loads are associated with managed coniferous followed by unmanaged woodland on peat soils. Calculations indicate that at steady state, acid deposition inputs reported for 1995–1997 result in a large proportion of all the woodland habitats identified receiving deposition loads in excess of their critical load; i.e. critical loads are exceeded. These are discussed in relation to future modelled depositions for 2010. Whilst significant widespread negative impacts of such deposition on UK woodland habitats have not been reported, the work serves to illustrate that if acid deposition inputs were maintained and projected emissions reductions not achieved, the long-term sustainability of large areas of woodland in the UK could be compromised. Keywords: critical loads, acid deposition, acidification, woodland, simple mass balance model

  3. Theoretical assessment of a proposal for the simplified determination of critical loads of elastic shells

    International Nuclear Information System (INIS)

    Malmberg, T.

    1986-08-01

    Within the context of the stability analysis of the cryostat of a fusion reactor the question was raised whether or not the rather lengthy conventional stability analysis can be circumvented by applying a simplified strategy based on common linear Finite Element computer programs. This strategy involves the static linear deformation analysis of the structure with and without imperfections. For some simple stability problems this approach has been shown to be successful. The purpose of this study is to derive a general proof of the validity of this approach for thin shells with arbitrary geometry under hydrostatic pressure or dead loading along the boundary. This general assessment involves two types of analyses: 1) A general stability analysis for thin shells; this is based on a simple nonlinear shell theory and a stability criterion in form of the neutral (indifferent) equilibrium condition. This result is taken as reference solution. 2) A general linear deformation analysis for thin imperfect shells and the definition of a suitable scalar parameter (β-parameter) which should represent the reciprocal of the critical load factor. It is shown that the simplified strategy (=β-parameter approach'') generally is not capable to predict the actual critical load factor irrespective whether there is a hydrostatic pressure loading or dead loading along the edge of the shell. This general result is in contrast to the observations made for some simple stability problems. Nevertheless, the results of this study do not exclude the possibility that the simplified strategy will give reasonable approximate solutions at least for a restricted class of stability problems. (orig./HP) [de

  4. Long-term modelling of nitrogen turnover and critical loads in a forested catchment using the INCA model

    Directory of Open Access Journals (Sweden)

    J.-J. Langusch

    2002-01-01

    Full Text Available Many forest ecosystems in Central Europe have reached the status of N saturation due to chronically high N deposition. In consequence, the NO3 leaching into ground- and surface waters is often substantial. Critical loads have been defined to abate the negative consequences of the NO3 leaching such as soil acidification and nutrient losses. The steady state mass balance method is normally used to calculate critical loads for N deposition in forest ecosystems. However, the steady state mass balance approach is limited because it does not take into account hydrology and the time until the steady state is reached. The aim of this study was to test the suitability of another approach: the dynamic model INCA (Integrated Nitrogen Model for European Catchments. Long-term effects of changing N deposition and critical loads for N were simulated using INCA for the Lehstenbach spruce catchment (Fichtelgebirge, NE Bavaria, Germany under different hydrological conditions. Long-term scenarios of either increasing or decreasing N deposition indicated that, in this catchment, the response of nitrate concentrations in runoff to changing N deposition is buffered by a large groundwater reservoir. The critical load simulated by the INCA model with respect to a nitrate concentration of 0.4 mg N l–1 as threshold value in runoff was 9.7 kg N ha–1yr–1 compared to 10 kg ha–1yr–1 for the steady state model. Under conditions of lower precipitation (520 mm the resulting critical load was 7.7 kg N ha–1yr–1 , suggesting the necessity to account for different hydrological conditions when calculating critical loads. The INCA model seems to be suitable to calculate critical loads for N in forested catchments under varying hydrological conditions e.g. as a consequence of climate change. Keywords: forest ecosystem, N saturation, critical load, modelling, long-term scenario, nitrate leaching, critical loads reduction, INCA

  5. Empirical and simulated critical loads for nitrogen deposition in California mixed conifer forests

    International Nuclear Information System (INIS)

    Fenn, M.E.; Jovan, S.; Yuan, F.; Geiser, L.; Meixner, T.; Gimeno, B.S.

    2008-01-01

    Empirical critical loads (CL) for N deposition were determined from changes in epiphytic lichen communities, elevated NO 3 - leaching in streamwater, and reduced fine root biomass in ponderosa pine (Pinus ponderosa Dougl. ex Laws.) at sites with varying N deposition. The CL for lichen community impacts of 3.1 kg ha -1 year -1 is expected to protect all components of the forest ecosystem from the adverse effects of N deposition. Much of the western Sierra Nevada is above the lichen-based CL, showing significant changes in lichen indicator groups. The empirical N deposition threshold and that simulated by the DayCent model for enhanced NO 3 - leaching were 17 kg N ha -1 year -1 . DayCent estimated that elevated NO 3 - leaching in the San Bernardino Mountains began in the late 1950s. Critical values for litter C:N (34.1), ponderosa pine foliar N (1.1%), and N concentrations (1.0%) in the lichen Letharia vulpina ((L.) Hue) are indicative of CL exceedance. - Critical loads for N deposition effects on lichens, trees and nitrate leaching provide benchmarks for protecting California forests

  6. Empirical and simulated critical loads for nitrogen deposition in California mixed conifer forests

    Energy Technology Data Exchange (ETDEWEB)

    Fenn, M.E. [USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, CA 92507 (United States)], E-mail: mfenn@fs.fed.us; Jovan, S. [USDA Forest Service, Pacific Northwest Research Station, 620 SW Main, Suite 400, Portland, OR 97205 (United States); Yuan, F. [Department of Hydrology and Water Resources, University of Arizona, Tucson, AZ 85721 (United States); Geiser, L. [USDA Forest Service, Pacific Northwest Air Resource Management Program, PO Box 1148, Corvallis, OR 97339 (United States); Meixner, T. [Department of Hydrology and Water Resources, University of Arizona, Tucson, AZ 85721 (United States); Gimeno, B.S. [Ecotoxicology of Air Pollution, CIEMAT (ed. 70), Avda. Complutense 22, 28040 Madrid (Spain)

    2008-10-15

    Empirical critical loads (CL) for N deposition were determined from changes in epiphytic lichen communities, elevated NO{sub 3}{sup -} leaching in streamwater, and reduced fine root biomass in ponderosa pine (Pinus ponderosa Dougl. ex Laws.) at sites with varying N deposition. The CL for lichen community impacts of 3.1 kg ha{sup -1} year{sup -1} is expected to protect all components of the forest ecosystem from the adverse effects of N deposition. Much of the western Sierra Nevada is above the lichen-based CL, showing significant changes in lichen indicator groups. The empirical N deposition threshold and that simulated by the DayCent model for enhanced NO{sub 3}{sup -}leaching were 17 kg N ha{sup -1} year{sup -1}. DayCent estimated that elevated NO{sub 3}{sup -} leaching in the San Bernardino Mountains began in the late 1950s. Critical values for litter C:N (34.1), ponderosa pine foliar N (1.1%), and N concentrations (1.0%) in the lichen Letharia vulpina ((L.) Hue) are indicative of CL exceedance. - Critical loads for N deposition effects on lichens, trees and nitrate leaching provide benchmarks for protecting California forests.

  7. Fast assessment of the critical principal stress direction for multiple separated multiaxial loadings

    Directory of Open Access Journals (Sweden)

    M. Cova

    2015-07-01

    Full Text Available The critical plane calculation for multiaxial damage assessment is often a demanding task, particularly for large FEM models of real components. Anyway, in actual engineering requests, sometime, it is possible to take advantage of the specific properties of the investigated case. This paper deals with the problem of a mechanical component loaded by multiple, but “time-separated”, multiaxial external loads. The specific material damage is dependent from the max principal stress variation with a significant mean stress sensitivity too. A specifically fitted procedure was developed for a fast computation, at each node of a large FEM model, of the direction undergoing the maximum fatigue damage; the procedure is defined according to an effective stress definition based on the max principal stress amplitude and mean value. The procedure is presented in a general form, applicable to the similar cases.

  8. On Input Vector Representation for the SVR model of Reactor Core Loading Pattern Critical Parameters

    International Nuclear Information System (INIS)

    Trontl, K.; Pevec, D.; Smuc, T.

    2008-01-01

    Determination and optimization of reactor core loading pattern is an important factor in nuclear power plant operation. The goal is to minimize the amount of enriched uranium (fresh fuel) and burnable absorbers placed in the core, while maintaining nuclear power plant operational and safety characteristics. The usual approach to loading pattern optimization involves high degree of engineering judgment, a set of heuristic rules, an optimization algorithm and a computer code used for evaluating proposed loading patterns. The speed of the optimization process is highly dependent on the computer code used for the evaluation. Recently, we proposed a new method for fast loading pattern evaluation based on general robust regression model relying on the state of the art research in the field of machine learning. We employed Support Vector Regression (SVR) technique. SVR is a supervised learning method in which model parameters are automatically determined by solving a quadratic optimization problem. The preliminary tests revealed a good potential of the SVR method application for fast and accurate reactor core loading pattern evaluation. However, some aspects of model development are still unresolved. The main objective of the work reported in this paper was to conduct additional tests and analyses required for full clarification of the SVR applicability for loading pattern evaluation. We focused our attention on the parameters defining input vector, primarily its structure and complexity, and parameters defining kernel functions. All the tests were conducted on the NPP Krsko reactor core, using MCRAC code for the calculation of reactor core loading pattern critical parameters. The tested input vector structures did not influence the accuracy of the models suggesting that the initially tested input vector, consisted of the number of IFBAs and the k-inf at the beginning of the cycle, is adequate. The influence of kernel function specific parameters (σ for RBF kernel

  9. Effect of Eccentricity of Load on Critical Force of Thin-Walled Columns CFRP

    Directory of Open Access Journals (Sweden)

    Pawel Wysmulski

    2017-09-01

    Full Text Available The subject of study was a thin-walled C-section made of carbon fiber reinforced polymer (CFRP. Column was subjected to eccentric compression in the established direction. In the computer simulation, the boundary conditions were assumed in the form of articulated support of the sections of the column. Particular studies included an analysis of the effects of eccentricity on the critical force value. The research was conducted using two independent research methods: numerical and experimental. Numerical simulations were done using the finite element method using the advanced system Abaqus®. The high sensitivity of the critical force value corresponding to the local buckling of the channel section to the load eccentricity was demonstrated.

  10. Simulation of Mechanical Behavior and Damage of a Large Composite Wind Turbine Blade under Critical Loads

    Science.gov (United States)

    Tarfaoui, M.; Nachtane, M.; Khadimallah, H.; Saifaoui, D.

    2018-04-01

    Issues such as energy generation/transmission and greenhouse gas emissions are the two energy problems we face today. In this context, renewable energy sources are a necessary part of the solution essentially winds power, which is one of the most profitable sources of competition with new fossil energy facilities. This paper present the simulation of mechanical behavior and damage of a 48 m composite wind turbine blade under critical wind loads. The finite element analysis was performed by using ABAQUS code to predict the most critical damage behavior and to apprehend and obtain knowledge of the complex structural behavior of wind turbine blades. The approach developed based on the nonlinear FE analysis using mean values for the material properties and the failure criteria of Tsai-Hill to predict failure modes in large structures and to identify the sensitive zones.

  11. Incorporating episodicity into estimates of Critical Loads for juvenile salmonids in Scottish streams

    Directory of Open Access Journals (Sweden)

    E. E. Bridcut

    2004-01-01

    Full Text Available Critical Load (CL methodology is currently used throughout Europe to assess the risks of ecological damage due to sulphur and nitrogen emissions. Critical acid neutralising capacity (ANCCRIT is used in CL estimates for freshwater systems as a surrogate for biological damage. Although UK CL maps presently use an ANC value of 0 μeq l-1, this value has been based largely on Norwegian lake studies, in which brown trout is chosen as a representative indicator organism. In this study, an ANC value specific for brown trout in Scottish streams was determined and issues were addressed such as salmon and trout sensitivity in streams, episodicity, afforestation and complicating factors such as dissolved organic carbon (DOC and labile aluminium (Al-L. Catchments with significant forest cover were selected to provide fishless sites and to provide catchment comparisons in unpolluted areas. Chemical factors were the primary determinant with land use a secondary determinant of the distribution of salmonid populations at the twenty-six study sites. ANC explained more variance in brown trout density than pH. The most significant index of episodicity was percent of time spent below an ANC of 0 μeq l-1. An ANCCRIT value of 39 μeq l-1 was obtained based on a 50% probability of brown trout occurrence. The use of this revised ANCCRIT value in the CL equation improved the relationship between trout status and exceedance of CLs. Uncertainties associated with variations in Al-L at any fixed ANCCRIT, particularly within forested catchments, and the role of DOC in modifying the toxicity of Al-L are discussed. Keywords: Critical Load, Critical acid neutralising capacity, brown trout, episodes, streams

  12. Prediction calculation of HTR-10 fuel loading for the first criticality

    International Nuclear Information System (INIS)

    Jing Xingqing; Yang Yongwei; Gu Yuxiang; Shan Wenzhi

    2001-01-01

    The 10 MW high temperature gas cooled reactor (HTR-10) was built at Institute of Nuclear Energy Technology, Tsinghua University, and the first criticality was attained in Dec. 2000. The high temperature gas cooled reactor physics simulation code VSOP was used for the prediction of the fuel loading for HTR-10 first criticality. The number of fuel element and graphite element was predicted to provide reference for the first criticality experiment. The prediction calculations toke into account the factors including the double heterogeneity of the fuel element, buckling feedback for the spectrum calculation, the effect of the mixture of the graphite and the fuel element, and the correction of the diffusion coefficients near the upper cavity based on the transport theory. The effects of impurities in the fuel and the graphite element in the core and those in the reflector graphite on the reactivity of the reactor were considered in detail. The first criticality experiment showed that the predicted values and the experiment results were in good agreement with little relative error less than 1%, which means the prediction was successful

  13. Lichen-based critical loads for atmospheric nitrogen deposition in Western Oregon and Washington Forests, USA

    Energy Technology Data Exchange (ETDEWEB)

    Geiser, Linda H., E-mail: lgeiser@fs.fed.u [US Forest Service Pacific Northwest Region Air Resource Management Program, Siuslaw National Forest, PO Box 1148, Corvallis, OR 97339 (United States); Jovan, Sarah E. [US Forest Service Forest Inventory and Analysis Program, Pacific Northwest Research Station, 620 SW Main St, Suite 400, Portland, OR 97205 (United States); Glavich, Doug A. [US Forest Service Pacific Northwest Region Air Resource Management Program, Siuslaw National Forest, PO Box 1148, Corvallis, OR 97339 (United States); Porter, Matthew K. [Laboratory for Atmospheric Research, Washington State University, Pullman, WA 99164 (United States)

    2010-07-15

    Critical loads (CLs) define maximum atmospheric deposition levels apparently preventative of ecosystem harm. We present first nitrogen CLs for northwestern North America's maritime forests. Using multiple linear regression, we related epiphytic-macrolichen community composition to: 1) wet deposition from the National Atmospheric Deposition Program, 2) wet, dry, and total N deposition from the Communities Multi-Scale Air Quality model, and 3) ambient particulate N from Interagency Monitoring of Protected Visual Environments (IMPROVE). Sensitive species declines of 20-40% were associated with CLs of 1-4 and 3-9 kg N ha{sup -1} y{sup -1} in wet and total deposition. CLs increased with precipitation across the landscape, presumably from dilution or leaching of depositional N. Tight linear correlation between lichen and IMPROVE data suggests a simple screening tool for CL exceedance in US Class I areas. The total N model replicated several US and European lichen CLs and may therefore be helpful in estimating other temperate-forest lichen CLs. - Lichen-based critical loads for N deposition in western Oregon and Washington forests ranged from 3 to 9 kg ha{sup -1} y{sup -1}, increasing with mean annual precipitation.

  14. Two Coupled Queues with Vastly Different Arrival Rates: Critical Loading Case

    Directory of Open Access Journals (Sweden)

    Charles Knessl

    2011-01-01

    Full Text Available We consider two coupled queues with a generalized processor sharing service discipline. The second queue has a much smaller Poisson arrival rate than the first queue, while the customer service times are of comparable magnitude. The processor sharing server devotes most of its resources to the first queue, except when it is empty. The fraction of resources devoted to the second queue is small, of the same order as the ratio of the arrival rates. We assume that the primary queue is heavily loaded and that the secondary queue is critically loaded. If we let the small arrival rate to the secondary queue be O(ε, where 0≤ε≪1, then in this asymptotic limit the number of customers in the first queue will be large, of order O(ε-1, while that in the second queue will be somewhat smaller, of order O(ε-1/2. We obtain a two-dimensional diffusion approximation for this model and explicitly solve for the joint steady state probability distribution of the numbers of customers in the two queues. This work complements that in (Morrison, 2010, which the second queue was assumed to be heavily or lightly loaded, leading to mean queue lengths that were O(ε-1 or O(1, respectively.

  15. Benzo[a]pyrene in urban environments of eastern Moscow: pollution levels and critical loads

    Science.gov (United States)

    Kasimov, Nikolay S.; Kosheleva, Natalia E.; Nikiforova, Elena M.; Vlasov, Dmitry V.

    2017-02-01

    Polycyclic aromatic hydrocarbons (PAHs), particularly benzo[a]pyrene (BaP), are toxic compounds emitted from various anthropogenic sources. Understanding the BaP concentrations, dynamics and decomposition in soil is required to assess the critical loads of BaP in urban environments. This study is the first attempt to evaluate all major input and output components of benzo[a]pyrene (BaP) balance and to calculate the permissible load on the urban environment in different land-use zones in the Eastern district of Moscow. BaP contamination of the snow cover in the Eastern district of Moscow was related to daily BaP fallout from the atmosphere. In 2010, the mean content of the pollutant in the snow dust was 1942 ng g-1, whereas the average intensity of its fallout was 7.13 ng m-2 per day. Across the territory, BaP winter fallout intensities varied from 0.3 to 1100 ng m-2 per day. The average BaP content in the surface (0-10 cm) soil horizons was 409 ng g-1, which is 83 times higher than the local background value and 20 times higher than the maximum permissible concentration (MPC) accepted in Russia. The variations in soil and snow BaP concentrations among different land-use zones were examined. A significant contribution of BaP from the atmosphere to urban soils was identified. Based on the measurements of BaP atmospheric fallout and BaP reserves in the soils, the critical loads of BaP for the land-use zones in the Eastern district were calculated for different values of degradation intensity and different exposure times. It was established that at an annual degradation intensity of 1-10 %, ecologically safe BaP levels in the soils of all land-use zones, excluding the agricultural zone, will only be reached after many decades or centuries.

  16. Influence of the heater material on the critical heat load at boiling of liquids on surfaces with different sizes

    Science.gov (United States)

    Anokhina, E. V.

    2010-05-01

    Data on critical heat loads q cr for the saturated and unsaturated pool boiling of water and ethanol under atmospheric pressure are reported. It is found experimentally that the critical heat load does not necessarily coincide with the heat load causing burnout of the heater, which should be taken into account. The absolute values of q cr for the boiling of water and ethanol on copper surfaces 65, 80, 100, 120, and 200 μm in diameter; tungsten surface 100 μm in diameter; and nichrome surface 100 μm in diameter are obtained experimentally.

  17. Susceptibility of forests in the northeastern USA to nitrogen and sulfur deposition: critical load exceedance and forest health

    Science.gov (United States)

    N. Duarte; L.H. Pardo; M.J. Robin-Abbott

    2013-01-01

    The objectives of this study were to assess susceptibility to acidification and nitrogen (N) saturation caused by atmospheric deposition to northeastern US forests, evaluate the benefits and shortcomings of making critical load assessments using regional data, and assess the relationship between expected risk (exceedance) and forest health. We calculated the critical...

  18. Determination and Distribution of Critical Loads: Application to the Forest Soils in the Autonomous Region of Madrid

    International Nuclear Information System (INIS)

    Sousa, M.; Schmid, T.; Rabago, I.

    2000-01-01

    The critical loads of acidity and sulphur have been determined for forest soils within the north and northwest of the Autonomous Region of Madrid. The SMB-CCE and SMB-PROFILE steady state models have been applied using a 1 km x 1 km resolution. The forest ecosystems have been characterised according to the soil and forest type, slope and climatic data using a Geographic Information System. In order to estimate the critical loads, processes such as weathering rate of the parent material, atmospheric deposition. critical alkalinity leaching rate and nutrients absorbed by the vegetation have been considered. In general the forest soils present high critical load values for acidity and sulphur. The more sensitive zones are found in the north of the Sierra of Guadarrama. Independent of the applied methods, the results are associated to the types of soils where Leptosols have the lowest, Cambisoles and Regosoles intermediate and Luvisoles the most elevated values. (Author) 40 refs

  19. Combining Ecosystem Service and Critical Load Concepts for Resource Management and Public Policy

    Directory of Open Access Journals (Sweden)

    Timothy J. Sullivan

    2012-11-01

    Full Text Available Land management and natural resource public policy decision-making in the United States can benefit from two resource damage/recovery concepts: ecosystem service (ES and critical load (CL. The purpose of this paper is to suggest an integrated approach to the application of ES and CL principles for public land management and natural resource policy decision-making. One well known example that is appropriate for ES and CL evaluation is examined here: the acidification of soil and drainage water by atmospheric deposition of acidifying sulfur and nitrogen compounds. A conceptual framework illustrates how the ES and CL approaches can be combined in a way that enhances the strengths of each. This framework will aid in the process of translating ES and CL principles into land management and natural resource policy decision-making by documenting the impacts of pollution on environmental goods and services that benefit humans.

  20. Mapping critical loads of nitrogen deposition for aquatic ecosystems in the Rocky Mountains, USA

    Science.gov (United States)

    Nanus, Leora; Clow, David W.; Saros, Jasmine E.; Stephens, Verlin C.; Campbell, Donald H.

    2012-01-01

    Spatially explicit estimates of critical loads of nitrogen (N) deposition (CLNdep) for nutrient enrichment in aquatic ecosystems were developed for the Rocky Mountains, USA, using a geostatistical approach. The lowest CLNdep estimates (-1 yr-1) occurred in high-elevation basins with steep slopes, sparse vegetation, and abundance of exposed bedrock and talus. These areas often correspond with areas of high N deposition (>3 kg N ha-1 yr-1), resulting in CLNdep exceedances ≥1.5 ± 1 kg N ha-1 yr-1. CLNdep and CLNdep exceedances exhibit substantial spatial variability related to basin characteristics and are highly sensitive to the NO3- threshold at which ecological effects are thought to occur. Based on an NO3- threshold of 0.5 μmol L-1, N deposition exceeds CLNdep in 21 ± 8% of the study area; thus, broad areas of the Rocky Mountains may be impacted by excess N deposition, with greatest impacts at high elevations.

  1. National implementation of the UNECE convention on long-range transboundary air pollution (effects). Pt. 2. Impacts and risk estimation, critical loads, biodiversity, dynamic modelling, critical level violation, material corrosion; Nationale Umsetzung UNECE-Luftreinhaltekonvention (Wirkungen). T. 2. Wirkungen und Risikoabschaetzungen Critical Loads, Biodiversitaet, Dynamische Modellierung, Critical Levels Ueberschreitungen, Materialkorrosion

    Energy Technology Data Exchange (ETDEWEB)

    Gauger, Thomas [Bundesforschungsanstalt fuer Landwirtschaft, Braunschweig (DE). Inst. fuer Agraroekologie (FAL-AOE); Stuttgart Univ. (Germany). Inst. fuer Navigation; Haenel, Hans-Dieter; Roesemann, Claus [Bundesforschungsanstalt fuer Landwirtschaft, Braunschweig (DE). Inst. fuer Agraroekologie (FAL-AOE); Nagel, Hans-Dieter; Becker, Rolf; Kraft, Philipp; Schlutow, Angela; Schuetze, Gudrun; Weigelt-Kirchner, Regine [OeKO-DATA Gesellschaft fuer Oekosystemanalyse und Umweltdatenmanagement mbH, Strausberg (Germany); Anshelm, Frank [Geotechnik Suedwest Frey Marx GbR, Bietigheim-Bissingen (Germany)

    2008-09-15

    The report on the implementation of the UNECE convention on long-range transboundary air pollution Pt.2 covers the following issues: The tasks of the NFC (National Focal Center) Germany including the ICP (international cooperative program) modeling and mapping and the expert panel for heavy metals. Results of the work for the multi-component protocol cover the initial data for the calculation of the critical loads following the mass balance method, critical loads for acid deposition, critical loads for nitrogen input, critical load violations (sulfur, nitrogen). The results of work for the heavy metal protocol cover methodology development and recommendations for ICO modeling and mapping in accordance with international development, contributions of the expert group/ task force on heavy metals (WGSR), data sets on the critical loads for lead, cadmium and mercury, and critical load violations (Pb, Cd, Hg). The results of work on the inclusion of biodiversity (BERN) cover data compilation, acquisition and integration concerning ecosystems, model validation and verification and the possible interpretation frame following the coupling with dynamic modeling. The future development and utilization of dynamic modeling covers model comparison, applicability, the preparation of a national data set and preparations concerning the interface to the BERN model.

  2. A dynamic modelling approach for estimating critical loads of nitrogen based on plant community changes under a changing climate

    International Nuclear Information System (INIS)

    Belyazid, Salim; Kurz, Dani; Braun, Sabine; Sverdrup, Harald; Rihm, Beat; Hettelingh, Jean-Paul

    2011-01-01

    A dynamic model of forest ecosystems was used to investigate the effects of climate change, atmospheric deposition and harvest intensity on 48 forest sites in Sweden (n = 16) and Switzerland (n = 32). The model was used to investigate the feasibility of deriving critical loads for nitrogen (N) deposition based on changes in plant community composition. The simulations show that climate and atmospheric deposition have comparably important effects on N mobilization in the soil, as climate triggers the release of organically bound nitrogen stored in the soil during the elevated deposition period. Climate has the most important effect on plant community composition, underlining the fact that this cannot be ignored in future simulations of vegetation dynamics. Harvest intensity has comparatively little effect on the plant community in the long term, while it may be detrimental in the short term following cutting. This study shows: that critical loads of N deposition can be estimated using the plant community as an indicator; that future climatic changes must be taken into account; and that the definition of the reference deposition is critical for the outcome of this estimate. - Research highlights: → Plant community changes can be used to estimate critical loads of nitrogen. → Climate change is decisive for future changes of geochemistry and plant communities. → Climate change cannot be ignored in estimates of critical loads. → The model ForSAFE-Veg was successfully used to set critical loads of nitrogen. - Plant community composition can be used in dynamic modelling to estimate critical loads of nitrogen deposition, provided the appropriate reference deposition, future climate and target plant communities are defined.

  3. Critical undrained shear strength of sand-silt mixtures under monotonic loading

    Directory of Open Access Journals (Sweden)

    Mohamed Bensoula

    2014-07-01

    Full Text Available This study uses experimental triaxial tests with monotonic loading to develop empirical relationships to estimate undrained critical shear strength. The effect of the fines content on undrained shear strength is analyzed for different density states. The parametric analysis indicates that, based on the soil void ratio and fine content properties, the undrained critical shear strength first increases and then decreases as the proportion of fines increases, which demonstrates the influence of fine content on a soil’s vulnerability to liquefaction. A series of monotonic undrained triaxial tests were performed on reconstituted saturated sand-silt mixtures. Beyond 30% fines content, a fraction of the silt participates in the soil’s skeleton chain force. In this context, the concept of the equivalent intergranular void ratio may be an appropriate parameter to express the critical shear strength of the studied soil. This parameter is able to control the undrained shear strength of non-plastic silt and sand mixtures with different densities.   Resumen Este estudio utiliza evaluaciones experimentales triaxiales con cargas repetitivas para desarrollar relaciones empíricas y estimar la tensión crítica de corte bajo condiciones no drenadas. El efecto de contenido de finos en la tensión de corte sin drenar se analizó en diferentes estados de densidad. El análisis paramétrico indica que, basado en la porosidad del suelo y las propiedades del material de finos, la tensión de corte sin drenar primero se incrementa y luego decrece mientras la proporción de finos aumenta, lo que demuestra la influencia de contenido de finos en la vulnerabilidad del suelo a la licuación. Una serie de las evaluaciones se realizó en  mezclas rehidratadas y saturadas de arena y cieno. Más allá del 30 % de los contenidos finos, una fracción del cieno hace parte principal de la cadena de fuerza del suelo. En este contexto, el concepto de porosidad equivalente

  4. Critical phosphorus loading of different types of shallow lakes and the consequences for management estimated with the ecosystem model PCLake

    NARCIS (Netherlands)

    Janse, J.H.; De Senerpont Domis, L.N.; Scheffer, M.; Lijklema, L.; Klinge, M.; Mooij, W.M.; Van Liere, L.

    2008-01-01

    Shallow lakes typically can be in one of two contrasting states: a clear state with submerged macrophytes or a turbid state dominated by phytoplankton. Eutrophication may cause a switch from the clear to the turbid state, if the phosphorus loading exceeds a critical value. Recovery of the clear

  5. Nuclear criticality safety: general. 4. The CASTOR X/32S Method of Covering mis-loading Concerns

    International Nuclear Information System (INIS)

    Lancaster, Dale B.; Rombough, Charles T.; Diersch, Rudolf; Spilker, Harry

    2001-01-01

    In the United States, most cask licenses do not directly consider mis-loading. If the enrichment limit for a shipping cask is high and the reactivity control is inherent in the cask, the reactivity effect of a mis-load is small. However, in large-capacity casks, such as the CASTOR X/32S, the effect can be much larger. The U.S. Department of Energy Topical Report on Actinide- Only Burnup Credit takes the position that a fuel assembly mis-load does need to be analyzed since there are multiple independent checks, and thus, the double-contingency principle is met. Unfortunately, 11 assemblies were mis-loaded at Palisades. This event has caused the U.S. Nuclear Regulatory Commission (NRC) to ask for more detail on prevention of mis-loading. In the summer of 1999, Palisades loaded 11 assemblies, which did not comply with the loading requirements for their VSC-24 cask. The cask requires 5 yr of cooling, and these 11 assemblies had just a little more than 4 yr of cooling. The mis-loading did not result in an unsafe condition but in an un-reviewed condition. This mis-loading was not identified until November 2000 during a review related to an NRC information notice. The loading plan for the cask was incorrect. The engineering review of the loading plan missed the error. The operators had loaded the cask consistent with the loading plan. The cask loading was then confirmed by comparing to the loading plan. The loading plan was in error since the engineer assumed that the entire region of fuel was discharged at the same time. The 11 assemblies of concern were reinserted in the reactor, and the engineer and the reviewer did not check for this. The reactor records for all the assemblies were correct but apparently were not checked by the engineer who created the loading plan. To prevent a mis-load criticality event, the following steps will be required for the CASTOR X/32S storage and transport cask: 1. A loading plan will be prepared for each cask loaded. This plan will be

  6. Recently surveyed lakes in northern Manitoba and Saskatchewan, Canada: characteristics and critical loads of acidity

    Directory of Open Access Journals (Sweden)

    Isaac WONG

    2010-08-01

    Full Text Available Based on minimal information, lakes in the western Canadian provinces of Manitoba (MB and Saskatchewan (SK have long been considered unaffected by acid rain. However, emissions of acidifying pollutants from MB smelters and oil sand processing in Alberta (AB may pose a developing threat. Surveys of 347 lakes located on geologically sensitive terrain in northern MB and SK were conducted to assess their acidification sensitivity and status. The survey domain (~193,000 km2 contained 81,494 lakes ≥1 ha in area. Small lakes dominated the inventory in terms of numbers, and large lakes dominated in terms of area. Survey lakes were selected using a stratified-random sampling design in 10 sampling blocks within the overall survey domain. Few lakes had pH <6, and only three (all in SK were acidic, i.e., Gran Alkalinity (Alk <0 μeq L–1. A broad range in lake sensitivity was apparent, and very sensitive lakes (low specific conductance, base cations and Alk were present in all sampling blocks. Dissolved organic carbon (DOC was an important constituent of many lakes. Critical loads (CL of acidity calculated using the Steady-State Water Chemistry model (SSWC revealed extremely low 5th percentile values for every block (range 1.9 to 52.7 eq ha–1 y–1. Block CL exceedances calculated using estimated S and N deposition for 2002 ranged from 54.5 to 909 eq ha–1 y–1. The largest exceedances were for sampling blocks located near smelter sources or downwind of the oil sands. Lake chemistry revealed by our surveys was compared to others conducted both nearby and outside Canada.

  7. Experimental critical loadings and control rod worths in LWR-PROTEUS configurations compared with MCNPX results

    International Nuclear Information System (INIS)

    Plaschy, M.; Murphy, M.; Jatuff, F.; Seiler, R.; Chawla, R.

    2006-01-01

    The PROTEUS research reactor at the Paul Scherrer Inst. (PSI) has been operating since the sixties and has already permitted, due to its high flexibility, investigation of a large range of very different nuclear systems. Currently, the ongoing experimental programme is called LWR-PROTEUS. This programme was started in 1997 and concerns large-scale investigations of advanced light water reactors (LWR) fuels. Until now, the different LWR-PROTEUS phases have permitted to study more than fifteen different configurations, each of them having to be demonstrated to be operationally safe, in particular, for the Swiss safety authorities. In this context, recent developments of the PSI computer capabilities have made possible the use of full-scale SD-heterogeneous MCNPX models to calculate accurately different safety related parameters (e.g. the critical driver loading and the shutdown rod worth). The current paper presents the MCNPX predictions of these operational characteristics for seven different LWR-PROTEUS configurations using a large number of nuclear data libraries. More specifically, this significant benchmarking exercise is based on the ENDF/B6v2, ENDF/B6v8, JEF2.2, JEFF3.0, JENDL3.2, and JENDL3.3 libraries. The results highlight certain library specific trends in the prediction of the multiplication factor k eff (e.g. the systematically larger reactivity calculated with JEF2.2 and the smaller reactivity associated with JEFF3.0). They also confirm the satisfactory determination of reactivity variations by all calculational schemes, for instance, due to the introduction of a safety rod pair, these calculations having been compared with experiments. (authors)

  8. Improving Middle School Students’ Critical Thinking Skills Through Reading Infusion-Loaded Discovery Learning Model in the Science Instruction

    Science.gov (United States)

    Nuryakin; Riandi

    2017-02-01

    A study has been conducted to obtain a depiction of middle school students’ critical thinking skills improvement through the implementation of reading infusion-loaded discovery learning model in science instruction. A quasi-experimental study with the pretest-posttest control group design was used to engage 55 eighth-year middle school students in Tasikmalaya, which was divided into the experimental and control group respectively were 28 and 27 students. Critical thinking skills were measured using a critical thinking skills test in multiple-choice with reason format questions that administered before and after a given instruction. The test was 28 items encompassing three essential concepts, vibration, waves and auditory senses. The critical thinking skills improvement was determined by using the normalized gain score and statistically analyzed by using Mann-Whitney U test.. The findings showed that the average of students’ critical thinking skills normalized gain score of both groups were 59 and 43, respectively for experimental and control group in the medium category. There were significant differences between both group’s improvement. Thus, the implementation of reading infusion-loaded discovery learning model could further improve middle school students’ critical thinking skills than conventional learning.

  9. Power load limits of the WENDELSTEIN 7-X target elements-comparison of experimental results and design values for power loads up to the critical heat flux

    International Nuclear Information System (INIS)

    Greuner, H; Boeswirth, B; Boscary, J; Leuprecht, A; Plankensteiner, A

    2007-01-01

    The power load limits of the WENDELSTEIN7-X divertor target elements were experimentally evaluated with heat loads considerably exceeding the expected operating conditions. The water-cooled elements are designed for steady-state heat flux of 10 MW m -2 and to remove a power load up to 100 kW. The elements must allow a limited operation time at 12 MW m -2 steady-state and should not fail for short pulses of up to 15 MW m -2 for cooling conditions in the subcooled nucleate boiling regime. In the framework of the qualification phase, pre-series target elements were loaded up to 24 MW m -2 without loss of CFC tiles. A critical heat flux at the target of 31 MW m -2 was achieved. The paper discusses the results of the tests performed at the high heat flux test facility GLADIS. The experimental results compared to transient nonlinear fine element method (FEM) calculations confirm a high thermal safety margin of the target design sufficient for plasma operation in W7-X

  10. Acid deposition and assessment of its critical load for the environmental health of waterbodies in a subtropical watershed, China

    Science.gov (United States)

    Jia, Junjie; Gao, Yang

    2017-12-01

    Atmospheric acidic deposition in subtropical watersheds poses an environmental risk of causing acidification of aquatic ecosystems. In this study, we evaluated the frequency of acid deposition in a subtropical forest ecosystem and the associated critical loads of acidity for a sensitive aquatic ecosystem. We found that out of 132 rainfall events, 33(25%) were acidic rainfall occurrences. Estimated wet acid deposition (2282.78 eq·ha-1·yr-1), consistent with SO42- and NH4+ deposition, was high in spring and summer and low in autumn and winter. Waterbodies surrounded by mixed wood and citrus orchard experience severe acidification, mostly from S deposition because acidic deposition exceeds the corresponding critical loads of acidity. Modifications that take acid rain deposition into consideration are needed for land-use and agricultural management strategies to improve the environmental health of waterbodies in subtropical watersheds.

  11. Colistin Population Pharmacokinetics after Application of a Loading Dose of 9 MU Colistin Methanesulfonate in Critically Ill Patients

    OpenAIRE

    Karaiskos, Ilias; Friberg, Lena E.; Pontikis, Konstantinos; Ioannidis, Konstantinos; Tsagkari, Vasiliki; Galani, Lamprini; Kostakou, Eirini; Baziaka, Fotini; Paskalis, Charalambos; Koutsoukou, Antonia; Giamarellou, Helen

    2015-01-01

    Colistin has been revived, in the era of extensively drug-resistant (XDR) Gram-negative infections, as the last-resort treatment in critically ill patients. Recent studies focusing on the optimal dosing strategy of colistin have demonstrated the necessity of a loading dose at treatment initiation (D. Plachouras, M. Karvanen, L. E. Friberg, E. Papadomichelakis, A. Antoniadou, I. Tsangaris, I. Karaiskos, G. Poulakou, F. Kontopidou, A. Armaganidis, O. Cars, and H. Giamarellou, Antimicrob Agents ...

  12. Inter-annual variations in water yield to lakes in northeastern Alberta: implications for estimating critical loads of acidity

    Directory of Open Access Journals (Sweden)

    Roderick HAZEWINKEL

    2010-08-01

    Full Text Available Stable isotopes of water were applied to estimate water yield to fifty lakes in northeastern Alberta as part of an acid sensitivity study underway since 2002 in the Athabasca Oil Sands Region (AOSR. Herein, we apply site-specific water yields for each lake to calculate critical loads of acidity using water chemistry data and a steady-state water chemistry model. The main goal of this research was to improve site-specific critical load estimates and to understand the sensitivity to hydrologic variability across a Boreal Plains region under significant oil sands development pressure. Overall, catchment water yields were found to vary significantly over the seven year monitoring period, with distinct variations among lakes and between different regions, overprinted by inter-annual climate-driven shifts. Analysis of critical load estimates based on site-specific water yields suggests that caution must be applied to establish hydrologic conditions and define extremes at specific sites in order to protect more sensitive ecosystems. In general, lakes with low (high water yield tended to be more (less acid sensitive but were typically less (more affected by interannual hydrological variations. While it has been customary to use long-term water yields to define a static critical load for lakes, we find that spatial and temporal variability in water yield may limit effectiveness of this type of assessment in areas of the Boreal Plain characterized by heterogeneous runoff and without a long-term lake-gauging network. Implications for predicting acidification risk are discussed for the AOSR.

  13. Ramifications of structural deformations on collapse loads of critically cracked pipe bends under in-plane bending and internal pressure

    Energy Technology Data Exchange (ETDEWEB)

    Sasidharan, Sumesh; Arunachalam, Veerappan; Subramaniam, Shanmugam [Dept. of Mechanical Engineering, National Institute of Technology, Tiruchirappalli (India)

    2017-02-15

    Finite-element analysis based on elastic-perfectly plastic material was conducted to examine the influence of structural deformations on collapse loads of circumferential through-wall critically cracked 90 .deg. pipe bends undergoing in-plane closing bending and internal pressure. The critical crack is defined for a through-wall circumferential crack at the extrados with a subtended angle below which there is no weakening effect on collapse moment of elbows subjected to in-plane closing bending. Elliptical and semioval cross sections were postulated at the bend regions and compared. Twice-elastic-slope method was utilized to obtain the collapse loads. Structural deformations, namely, ovality and thinning, were each varied from 0% to 20% in steps of 5% and the normalized internal pressure was varied from 0.2 to 0.6. Results indicate that elliptic cross sections were suitable for pipe ratios 5 and 10, whereas for pipe ratio 20, semioval cross sections gave satisfactory solutions. The effect of ovality on collapse loads is significant, although it cancelled out at a certain value of applied internal pressure. Thinning had a negligible effect on collapse loads of bends with crack geometries considered.

  14. The Impact of Load Carriage on Measures of Power and Agility in Tactical Occupations: A Critical Review

    Directory of Open Access Journals (Sweden)

    Aaron Joseph

    2018-01-01

    Full Text Available The current literature suggests that load carriage can impact on a tactical officer’s mobility, and that survival in the field may rely on the officer’s mobility. The ability for humans to generate power and agility is critical for performance of the high-intensity movements required in the field of duty. The aims of this review were to critically examine the literature investigating the impacts of load carriage on measures of power and agility and to synthesize the findings. The authors completed a search of the literature using key search terms in four databases. After relevant studies were located using strict inclusion and exclusion criteria, the studies were critically appraised using the Downs and Black Checklist and relevant data were extracted and tabled. Fourteen studies were deemed relevant for this review, ranging in percentage quality scores from 42.85% to 71.43%. Outcome measures used in these studies to indicate levels of power and agility included short-distance sprints, vertical jumps, and agility runs, among others. Performance of both power and agility was shown to decrease when tactical load was added to the participants. This suggests that the increase in weight carried by tactical officers may put this population at risk of injury or fatality in the line of duty.

  15. The Impact of Load Carriage on Measures of Power and Agility in Tactical Occupations: A Critical Review.

    Science.gov (United States)

    Joseph, Aaron; Wiley, Amy; Orr, Robin; Schram, Benjamin; Dawes, J Jay

    2018-01-07

    The current literature suggests that load carriage can impact on a tactical officer's mobility, and that survival in the field may rely on the officer's mobility. The ability for humans to generate power and agility is critical for performance of the high-intensity movements required in the field of duty. The aims of this review were to critically examine the literature investigating the impacts of load carriage on measures of power and agility and to synthesize the findings. The authors completed a search of the literature using key search terms in four databases. After relevant studies were located using strict inclusion and exclusion criteria, the studies were critically appraised using the Downs and Black Checklist and relevant data were extracted and tabled. Fourteen studies were deemed relevant for this review, ranging in percentage quality scores from 42.85% to 71.43%. Outcome measures used in these studies to indicate levels of power and agility included short-distance sprints, vertical jumps, and agility runs, among others. Performance of both power and agility was shown to decrease when tactical load was added to the participants. This suggests that the increase in weight carried by tactical officers may put this population at risk of injury or fatality in the line of duty.

  16. Load-Unload Response Ratio and Accelerating Moment/Energy Release Critical Region Scaling and Earthquake Prediction

    Science.gov (United States)

    Yin, X. C.; Mora, P.; Peng, K.; Wang, Y. C.; Weatherley, D.

    The main idea of the Load-Unload Response Ratio (LURR) is that when a system is stable, its response to loading corresponds to its response to unloading, whereas when the system is approaching an unstable state, the response to loading and unloading becomes quite different. High LURR values and observations of Accelerating Moment/Energy Release (AMR/AER) prior to large earthquakes have led different research groups to suggest intermediate-term earthquake prediction is possible and imply that the LURR and AMR/AER observations may have a similar physical origin. To study this possibility, we conducted a retrospective examination of several Australian and Chinese earthquakes with magnitudes ranging from 5.0 to 7.9, including Australia's deadly Newcastle earthquake and the devastating Tangshan earthquake. Both LURR values and best-fit power-law time-to-failure functions were computed using data within a range of distances from the epicenter. Like the best-fit power-law fits in AMR/AER, the LURR value was optimal using data within a certain epicentral distance implying a critical region for LURR. Furthermore, LURR critical region size scales with mainshock magnitude and is similar to the AMR/AER critical region size. These results suggest a common physical origin for both the AMR/AER and LURR observations. Further research may provide clues that yield an understanding of this mechanism and help lead to a solid foundation for intermediate-term earthquake prediction.

  17. Droop Control of Solar PV, Grid and Critical Load using Suppressing DC Current Injection Technique without Battery Storage

    Science.gov (United States)

    Dama Mr., Jayachandra; (Mrs. , Lini Mathew, Dr.; Srikanth Mr., G.

    2017-08-01

    This paper presents design of a sustainable solar Photo voltaic system for an Indian cities based residential/community house, integrated with grid, supporting it as supplementary sources, to meet energy demand of domestic loads. The role of renewable energy sources in Distributed Generation (DG) is increasingly being recognized as a supplement and an alternative to large conventional central power supply. Though centralized economic system that solely depends on cities is hampered due to energy deficiency, the use of solar energy in cities is never been tried widely due to technical inconvenience and high installation cost. To mitigate these problems, this paper proposes an optimized design of grid-tied PV system without storage which is suitable for Indian origin as it requires less installallation cost and supplies residential loads when the grid power is unavailable. The energy requirement is mainly fulfilled from PV energy module for critical load of a city located residential house and supplemented by grid/DG for base and peak load. The system has been developed for maximum daily household demand of 50kWp and can be scaled to any higher value as per requirement of individual/community building ranging from 50kWp to 60kWp as per the requirement. A simplified control system model has been developed to optimize and control flow of power from these sources. The simulation work, using MATLAB Simulink software for proposed energy management, has resulted in an optimal yield leading efficient power flow control of proposed system.

  18. Completion of UO2 pellets production and fuel rods load for the RA-8 critical facility

    International Nuclear Information System (INIS)

    Marajofsky, Adolfo; Perez, Lidia E.; Thern, Gerardo G.; Altamirano, Jorge S.; Benitez, Ana M.; Cardenas, Hugo R.; Becerra, Fabian A.; Perez, Aldo E.; Fuente, Mariano de la

    1999-01-01

    The Advanced Fuels Division produced fuel pellets of 235 U with 1.8% and 3.6% enrichment and Zry-4 cladding loads for the RA-8 reactor at Pilcaniyeu Technological Unit. For economical and availability reasons, the powder acquired was initially UO 2 with 3.4% enrichment in 235 U, therefore the 235 U powder with 1.8% enrichment was produced by mechanical mixture. The production of fuel pellets for both enrichments was carried out by cold pressing and sintering processes in reducing atmosphere. The load of Zry-4 claddings was performed manually. The production stages can be divided into setup, qualification and production. This production allows not only to fulfill satisfactorily the new fuel rods supply for the RA-8 reactor but also to count with a new equipment and skilled personnel as well as to meet quality and assurance control methods for future pilot-scale production and even new fuel elements production. (author)

  19. A critical pressure based panel method for prediction of unsteady loading of marine propellers under cavitation

    International Nuclear Information System (INIS)

    Liu, P.; Bose, N.; Colbourne, B.

    2002-01-01

    A simple numerical procedure is established and implemented into a time domain panel method to predict hydrodynamic performance of marine propellers with sheet cavitation. This paper describes the numerical formulations and procedures to construct this integration. Predicted hydrodynamic loads were compared with both a previous numerical model and experimental measurements for a propeller in steady flow. The current method gives a substantial improvement in thrust and torque coefficient prediction over a previous numerical method at low cavitation numbers of less than 2.0, where severe cavitation occurs. Predicted pressure coefficient distributions are also presented. (author)

  20. Criticality safety study of dry spent fuel cask loaded with increased enrichment fuel

    International Nuclear Information System (INIS)

    Bznuni, S.; Baghdasaryan, N.; Amirjanyan, A.

    2013-01-01

    Existing Dry Spent Fuel Casks (DSC) for transporting and storing of Armenian NPP fuel was licensed for WWER-440 fuel assemblies with 3.6% enrichment. Having in mind that ANPP introduced new fuel assemblies with increased enrichment (3.82 %) re-assessment of criticality safety analysis for DSC is required. Criticality safety analysis of DSC was performed by KENO-VI program using 238-GROUP ENDF/B-VII.0 LIBRARY (V7-238). Results of analysis showed that additional 8 borated racks for fuel assemblies should be included in the design of DSC. In addition feasibility study was performed to find out level of burnup-credit approach implementation to keep current design of DSC unchanged. Burnup-credit analysis was performed by STARBUCS program using axial burnup profiles from Armenian NPP neutronics analysis carried out by BIPR code. (authors)

  1. Improvement of the skeleton tables for calculation of the critical heat load

    International Nuclear Information System (INIS)

    Gotovskij, M.A.; Kvetnyj, M.A.

    2002-01-01

    Paper presents analysis of drawbacks of the skeleton tables of the critical heat flows applied in calculated heat and hydraulic codes. Paper demonstrates the necessity to take account of specific nature of mechanisms of dryout crisis, of boiling crisis at slow mass rates and the range of small underheatings up to temperature of saturation. Attention is drawn to necessity of detailed account of the natural limitations of the application field of the skeleton tables [ru

  2. Critical Loads of Atmospheric Nitrogen Deposition for Aquatic Ecosystems in Yosemite and Sequoia and Kings Canyon National Parks

    Science.gov (United States)

    Nanus, L.; Clow, D. W.; Sickman, J. O.

    2016-12-01

    High-elevation aquatic ecosystems in Yosemite (YOSE) and Sequoia and Kings Canyon (SEKI) National Parks are impacted by atmospheric nitrogen (N) deposition associated with local and regional air pollution. Documented effects include elevated surface water nitrate concentrations, increased algal productivity, and changes in diatom species assemblages. Annual wet inorganic N deposition maps, developed at 1-km resolution for YOSE and SEKI to quantify N deposition to sensitive high-elevation ecosystems, range from 1.0 to over 5.0 kg N ha-1 yr-1. Critical loads of N deposition for nutrient enrichment of aquatic ecosystems were quantified and mapped using a geostatistical approach, with N deposition, topography, vegetation, geology, and climate as potential explanatory variables. Multiple predictive models were created using various combinations of explanatory variables; this approach allowed us to better quantify uncertainty and more accurately identify the areas most sensitive to atmospherically deposited N. The lowest critical loads estimates and highest exceedances identified within YOSE and SEKI occurred in high-elevation basins with steep slopes, sparse vegetation, and areas of neoglacial till and talus. These results are consistent with previous analyses in the Rocky Mountains, and highlight the sensitivity of alpine ecosystems to atmospheric N deposition.

  3. Numerical and Experimental Investigation on the Structural Behaviour of a Horizontal Stabilizer under Critical Aerodynamic Loading Conditions

    Directory of Open Access Journals (Sweden)

    R. Sepe

    2017-01-01

    Full Text Available The aim of the proposed research activity is to investigate the mechanical behaviour of a part of aerospace horizontal stabilizer, made of composite materials and undergoing static loads. The prototype design and manufacturing phases have been carried out in the framework of this research activity. The structural components of such stabilizer are made of composite sandwich panels (HTA 5131/RTM 6 with honeycomb core (HRH-10-1/8-4.0; the sandwich skins have been made by means of Resin Transfer Moulding (RTM process. In order to assess the mechanical strength of this stabilizer, experimental tests have been performed. In particular, the most critical inflight recorded aerodynamic load has been experimentally reproduced and applied on the stabilizer. A numerical model, based on the Finite Element Method (FEM and aimed at reducing the experimental effort, has been preliminarily developed to calibrate amplitude, direction, and distribution of an equivalent and simpler load vector to be used in the experimental test. The FEM analysis, performed by using NASTRAN code, has allowed modelling the skins of the composite sandwich plates by definition of material properties and stack orientation of each lamina, while the honeycomb core has been modelled by using an equivalent orthotropic plate. Numerical and experimental results have been compared and a good agreement has been achieved.

  4. Evaluation of nuclear characteristics of minor actinide loaded core. Analyses of BFS-69 and BFS-66-2 critical experiments

    International Nuclear Information System (INIS)

    Hazama, Taira; Sato, Wakaei

    2010-09-01

    Collaboration with Russian Institute of Physics and Power Engineering named 'Investigation of neutronic-physical characteristics and their change when introducing large quantity of neptunium (Np) at different BFS critical assemblies' has been accomplished. This is the second report of the collaboration to describe experimental information and analysis results on BFS-69 and BFS-66-2 critical experiments. In the experiments, various nuclear characteristics were measured in 2 kinds of cores with/without Np loading of about 8 kg. JAEA's standard analysis results were presented with four kinds of nuclear data (JENDL-3.2, JENDL-3.3, JENDL/AC-2008, and ENDF/BVII). Analytical results show: 1) An overestimation trend has been observed in BFS-69 criticality results, especially with JENDL-3.3 and JENDL/AC-2008. The difference from ENDF/B-II having better results mainly lies in the average cosine of the scattering angle around 1 MeV. 2) A small discrepancy exists in BFS-69 Na void reactivity results with the three JENDL nuclear data. The difference from ENDF/B-II mainly lies in scattering cross sections of sodium around 1 MeV and fission cross section of 239 Pu around 1 keV. 3) The analysis results simulate measured Np effects on nuclear characteristics within experimental errors. (author)

  5. Colistin Population Pharmacokinetics after Application of a Loading Dose of 9 MU Colistin Methanesulfonate in Critically Ill Patients.

    Science.gov (United States)

    Karaiskos, Ilias; Friberg, Lena E; Pontikis, Konstantinos; Ioannidis, Konstantinos; Tsagkari, Vasiliki; Galani, Lamprini; Kostakou, Eirini; Baziaka, Fotini; Paskalis, Charalambos; Koutsoukou, Antonia; Giamarellou, Helen

    2015-12-01

    Colistin has been revived, in the era of extensively drug-resistant (XDR) Gram-negative infections, as the last-resort treatment in critically ill patients. Recent studies focusing on the optimal dosing strategy of colistin have demonstrated the necessity of a loading dose at treatment initiation (D. Plachouras, M. Karvanen, L. E. Friberg, E. Papadomichelakis, A. Antoniadou, I. Tsangaris, I. Karaiskos, G. Poulakou, F. Kontopidou, A. Armaganidis, O. Cars, and H. Giamarellou, Antimicrob Agents Chemother 53:3430-3436, 2009, http://dx.doi.org/10.1128/AAC.01361-08; A. F. Mohamed, I. Karaiskos, D. Plachouras, M. Karvanen, K. Pontikis, B. Jansson, E. Papadomichelakis, A. Antoniadou, H. Giamarellou, A. Armaganidis, O. Cars, and L. E. Friberg, Antimicrob Agents Chemother 56:4241- 4249, 2012, http://dx.doi.org/10.1128/AAC.06426-11; S. M. Garonzik, J. Li, V. Thamlikitkul, D. L. Paterson, S. Shoham, J. Jacob, F. P. Silveira, A. Forrest, and R. L. Nation, Antimicrob Agents Chemother 55:3284-3294, 2011, http://dx.doi.org/10.1128/AAC.01733-10). In 19 critically ill patients with suspected or microbiologically documented infections caused by XDR Gram-negative strains, a loading dose of 9 MU colistin methanesulfonate (CMS) (∼ 270 mg colistin base activity) was administered with a maintenance dose of 4.5 MU every 12 h, commenced after 24 h. Patients on renal replacement were excluded. CMS infusion was given over 30 min or 1 h. Repeated blood sampling was performed after the loading dose and after the 5th or 6th dose. Colistin concentrations and measured CMS, determined after hydrolization to colistin and including the partially sulfomethylated derivatives, were determined with a liquid chromatography-tandem mass spectrometry assay. Population pharmacokinetic analysis was conducted in NONMEM with the new data combined with data from previous studies. Measured colistimethate concentrations were described by 4 compartments for distribution and removal of sulfomethyl groups, while

  6. Analysis of ex-core detector response measured during nuclear ship Mutsu land-loaded core critical experiment

    International Nuclear Information System (INIS)

    Itagaki, M.; Abe, J.I.; Kuribayashi, K.

    1987-01-01

    There are some cases where the ex-core neutron detector response is dependent not only on the fission source distribution in a core but also on neutron absorption in the borated water reflector. For example, an unexpectedly large response variation was measured during the nuclear ship Mutsu land-loaded core critical experiment. This large response variation is caused largely by the boron concentration change associated with the change in control rod positioning during the experiment. The conventional Crump-Lee response calculation method has been modified to take into account this boron effect. The correction factor in regard to this effect has been estimated using the one-dimensional transport code ANISN. The detector response variations obtained by means of this new calculation procedure agree well with the measured values recorded during the experiment

  7. How to Secure UPS Operation And Supply of Safety Critical Load During Abnormal Conditions in Upstream Supply

    International Nuclear Information System (INIS)

    Andersen, Gert; Kissling, Silvan; Laaser, Joerg

    2015-01-01

    UPS system design margins are usually given by manufacturer, but the events in Forsmark showed that these margins are not sufficient to protect UPS equipment and secure supply to critical loads. To withstand such events, it is not enough just to define margins for particular equipment. The overall plant design including environmental influences must be taken into consideration. For extreme environmental conditions, a UPS must include protection which design is matching to the upstream plant equipment. Immunity against abnormal conditions can not be finally guaranteed by higher margins. A limitation that excludes such influences must be implemented into the design. This presentation discusses possibilities to specify design margins, for rectifiers and inverters based on GUTOR thyristor and IGBT technology. It shows protection features to resist and solutions to limit overvoltages. (authors)

  8. A novel modeling to predict the critical current behavior of Nb$_{3}$Sn PIT strand under transverse load based on a scaling law and Finite Element Analysis

    CERN Document Server

    Wang, Tiening; Takayasu, Makoto; Bordini, Bernardo

    2014-01-01

    Superconducting Nb$_{3}$Sn Powder-In-Tube (PIT) strands could be used for the superconducting magnets of the next generation Large Hadron Collider. The strands are cabled into the typical flat Rutherford cable configuration. During the assembly of a magnet and its operation the strands experience not only longitudinal but also transverse load due to the pre-compression applied during the assembly and the Lorentz load felt when the magnets are energized. To properly design the magnets and guarantee their safe operation, mechanical load effects on the strand superconducting properties are studied extensively; particularly, many scaling laws based on tensile load experiments have been established to predict the critical current dependence on strain. However, the dependence of the superconducting properties on transverse load has not been extensively studied so far. One of the reasons is that transverse loading experiments are difficult to conduct due to the small diameter of the strand (about 1 mm) and the data ...

  9. Critical levels and loads of atmospheric pollutants for terrestrial and aquatic ecosystems. The emergence of a scientific concept. Application potentials and their limits

    International Nuclear Information System (INIS)

    Landmann, G.

    1993-01-01

    The 'critical loads and levels' are defined as the highest atmospheric deposition rate or concentration of a gaseous pollutant, respectively, that will not cause harmful effects on sensitive elements of an ecosystem. The recent emergence of the concept of critical loads and levels is described, from the first explicit mention in 1986 to the production of the first European maps in 1991. The difficulties linked to the definition of the concept and to its english-derived terminology are discussed. The main approaches used for assessing critical loads and levels are briefly described. Important research is developed under the auspices of the Convention of Geneva (Long Range Transboundary Air Pollution Transport, UN-ECE), arising from intensive studies which have been carried out on the effects of air pollution on terrestrial and aquatic ecosystems for the past ten or fifteen years. Current knowledge is summarized, as well as the remaining gaps (and questions) which hinder the calculation of the critical thresholds. Finally, beyond the fundamental relevance of this scientifically sound and easily understood concept, its limits are pointed out. In brief, the 'critical loads and levels' concept is attractive and motivating to many scientists: it implies to apply an integrated and finalized approach, favors the prospecting of poorly known ecosystems and regions, and represents an interesting interface with decision makers

  10. Manual for calculating critical loads of heavy metals for soils and surface waters; preliminary guidelines for environmental quality criteria, calculation methods and input data

    NARCIS (Netherlands)

    Vries, de W.; Bakker, D.J.

    1996-01-01

    Methodologies are described for calculating critical loads of lead, cadmium, copper, zinc, nickel, chromium and mercury for soils and surface waters. The aspects which are discussed are: selection of a computation model, determination of environmental-quality criteria for the metals, collection of

  11. Ecological ranges for the pH and NO3 of syntaxa: a new basis for the estimation of critical loads for acid and nitrogen deposition

    NARCIS (Netherlands)

    Wamelink, G.W.W.; Goedhart, P.W.; Malinowska, A.H.; Frissel, J.Y.; Wegman, R.M.A.; Slim, P.A.; Dobben, van H.F.

    2011-01-01

    Question: Can the abiotic ranges of syntaxonomic units (associations) in terms of pH and nitrate concentration be estimated and then in principle be used to estimate critical loads for acid and nitrogen deposition? Location: Europe. Methods: Using splines, abiotic ranges of syntaxonomic units were

  12. Critical Loads of Acid Deposition for Wilderness Lakes in the Sierra Nevada (California) Estimated by the Steady-State Water Chemistry Model

    Science.gov (United States)

    Glenn D. Shaw; Ricardo Cisneros; Donald Schweizer; James O. Sickman; Mark E. Fenn

    2014-01-01

    Major ion chemistry (2000-2009) from 208 lakes (342 sample dates and 600 samples) in class I and II wilderness areas of the Sierra Nevada was used in the Steady-State Water Chemistry (SSWC) model to estimate critical loads for acid deposition and investigate the current vulnerability of high elevation lakes to acid deposition. The majority of the lakes were dilute (...

  13. The impact of acid deposition and forest harvesting on lakes and their forested catchments in south central Ontario: a critical loads approach

    Directory of Open Access Journals (Sweden)

    S. A. Watmough

    2002-01-01

    Full Text Available The impact of acid deposition and tree harvesting on three lakes and their representative sub-catchments in the Muskoka-Haliburton region of south-central Ontario was assessed using a critical loads approach. As nitrogen dynamics in forest soils are complex and poorly understood, for simplicity and to allow comparison among lakes and their catchments, CLs (A for both lakes and forest soils were calculated assuming that nitrate leaching from catchments will not change over time (i.e. a best case scenario. In addition, because soils in the region are shallow, base cation weathering rates for the representative sub-catchments were calculated for the entire soil profile and these estimates were also used to calculate critical loads for the lakes. These results were compared with critical loads obtained by the Steady State Water Chemistry (SSWC model. Using the SSWC model, critical loads for lakes were between 7 and 19 meq m-2yr-1 higher than those obtained from soil measurements. Lakes and forests are much more sensitive to acid deposition if forests are harvested, but two acid-sensitive lakes had much lower critical loads than their respective forested sub-catchments implying that acceptable acid deposition levels should be dictated by the most acid-sensitive lakes in the region. Under conditions that assume harvesting, the CL (A is exceeded at two of the three lakes and five of the six sub-catchments assessed in this study. However, sulphate export from catchments greatly exceeds input in bulk deposition and, to prevent lakes from falling below the critical chemical limit, sulphate inputs to lakes must be reduced by between 37% and 92% if forests are harvested. Similarly, sulphate leaching from forested catchments that are harvested must be reduced by between 16 and 79% to prevent the ANC of water draining the rooting zone from falling below 0 μeq l-1. These calculations assume that extremely low calcium leaching losses (9–27 μeq l-1 from

  14. Variability of electricity load patterns and its effect on demand response: A critical peak pricing experiment on Korean commercial and industrial customers

    International Nuclear Information System (INIS)

    Jang, Dongsik; Eom, Jiyong; Jae Park, Min; Jeung Rho, Jae

    2016-01-01

    To the extent that demand response represents an intentional electricity usage adjustment to price changes or incentive payments, consumers who exhibit more-variable load patterns on normal days may be capable of altering their loads more significantly in response to dynamic pricing plans. This study investigates the variation in the pre-enrollment load patterns of Korean commercial and industrial electricity customers and their impact on event-day loads during a critical peak pricing experiment in the winter of 2013. Contrary to conventional approaches to profiling electricity loads, this study proposes a new clustering technique based on variability indices that collectively represent the potential demand–response resource that these customers would supply. Our analysis reveals that variability in pre-enrollment load patterns does indeed have great predictive power for estimating their impact on demand–response loads. Customers in relatively low-variability clusters provided limited or no response, whereas customers in relatively high-variability clusters consistently presented large load impacts, accounting for most of the program-level peak reductions. This study suggests that dynamic pricing programs themselves may not offer adequate motivation for meaningful adjustments in load patterns, particularly for customers in low-variability clusters. - Highlights: • A method of clustering customers by variability indices is developed. • Customers in high-variability clusters provide substantial peak reductions. • Low-variability clusters exhibit limited reductions. • For low-variability customers, alternative policy instruments is well advised. • A model of discerning customer's demand response potential is suggested.

  15. Investigation on the Performance of UPQC-Q for Voltage Sag Mitigation and PQ Improvement at a Critical Load Point

    OpenAIRE

    Basu, Malabika; Das, S. P.; Dubey, Gopal

    2008-01-01

    The unified power quality conditioner (UPQC) is one of the major custom power solutions, which is capable of mitigating the effect of supply voltage sag at the load end or at the point of common coupling (PCC) in a distributed network. It also prevents the propagation of the load current harmonics to the utility and improves the input power factor of the load. The control of series compensator (SERC) of the UPQC is such that it injects voltage in quadrature advance to the supply current. Thus...

  16. Probability based load criteria for the design of nuclear structures: a critical review of the state-of-the-art

    Energy Technology Data Exchange (ETDEWEB)

    Shinozuka, M.; Ellingwood, B.R.; Wang, P.C.; Meyer, C.; Wen, Y.K.; Kao, S.; Shooman, M.L.; Philippacopoulos, A.J.

    1981-04-01

    Structures for nuclear power plant facilities must be designed to withstand safely and effectively all kinds of loads and load combinations that may be expected to occur during their lifetime. The traditional methods of structural design attempt to account for the inevitable variability in the loads, material strengths, in-service environments, and fabrication process, etc., through the use of safety factor, allowable stresses or load and resistance factors. These approaches may result in an unknown and nonuniform reliability because of the subjective manner in which the safety factors have been determined. The stochastic nature loads and the uncertainties in material properties dictate a probabilistic approach for a rational assessment of structural safety and performance. This report presents: an in-depth review of the state-of-the-art pertaining to probability-based analysis and design of civil engineering structures; basis for extending existing probability-based methods to seismic category I nuclear structures; and the availability of the pertinent data required to perform probabilistic analysis for seismic category I nuclear structures.

  17. Structural biomechanics of the craniomaxillofacial skeleton under maximal masticatory loading: Inferences and critical analysis based on a validated computational model.

    Science.gov (United States)

    Pakdel, Amir R; Whyne, Cari M; Fialkov, Jeffrey A

    2017-06-01

    The trend towards optimizing stabilization of the craniomaxillofacial skeleton (CMFS) with the minimum amount of fixation required to achieve union, and away from maximizing rigidity, requires a quantitative understanding of craniomaxillofacial biomechanics. This study uses computational modeling to quantify the structural biomechanics of the CMFS under maximal physiologic masticatory loading. Using an experimentally validated subject-specific finite element (FE) model of the CMFS, the patterns of stress and strain distribution as a result of physiological masticatory loading were calculated. The trajectories of the stresses were plotted to delineate compressive and tensile regimes over the entire CMFS volume. The lateral maxilla was found to be the primary vertical buttress under maximal bite force loading, with much smaller involvement of the naso-maxillary buttress. There was no evidence that the pterygo-maxillary region is a buttressing structure, counter to classical buttress theory. The stresses at the zygomatic sutures suggest that two-point fixation of zygomatic complex fractures may be sufficient for fixation under bite force loading. The current experimentally validated biomechanical FE model of the CMFS is a practical tool for in silico optimization of current practice techniques and may be used as a foundation for the development of design criteria for future technologies for the treatment of CMFS injury and disease. Copyright © 2017 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  18. Atmospheric dry and wet deposition of sulphur and nitrogen species and assessment of critical loads of acidic deposition exceedance in South Africa

    Directory of Open Access Journals (Sweden)

    Stuart J. Piketh

    2011-03-01

    Full Text Available We tested the hypothesis that acidic atmospheric pollution deposition, originating from the South African central industrial area, poses an environmental threat across a larger region within the dispersal footprint. A network of 37 passive monitoring sites to measure SO2 and NO2 was operated from August 2005 to September 2007. The area extended over the entire northern and eastern interior of South Africa. Monitoring locations were chosen to avoid direct impacts from local sources such as towns, mines and highways. Dry deposition rates of SO2 and NO2 were calculated from the measured concentrations. Concentrations of sulphur and nitrogen species in wet deposition from a previous study were used in conjunction with measured rainfall for the years 2006 and 2007 to estimate the wet deposition over the region. The calculated total (non-organic acidic deposition formed the basis for an assessment of exceedance of critical loads based on sensitivity of the regional soils. Regional soil sensitivity was determined by combining two major soil attributes available in the World Inventory of Soil Emission Potentials (International Soil Reference and Information Centre. Results indicate that certain parts of the central pollution source area on the South African Highveld have the potential for critical load exceedance, while limited areas downwind show lower levels of exceedance. Areas upwind and remote areas up and downwind, including forested areas of the Drakensberg escarpment, do not show any exceedance of the critical loads.

  19. The EU-strategy against soil acidification. Concept of the critical load; Die EU-Strategie gegen Bodenversauerung. Konzept der kritischen Belastung

    Energy Technology Data Exchange (ETDEWEB)

    Trautwein, W.P.

    1998-10-01

    The development of so-called `novel forest damages` is considered to be - at least partly - a result of the impact of certain air pollutants such as sulphur and nitrogen oxides; these precipitate as acid rain and acidify the soil, thus damaging sensitive ecosystems, e.g. forests. To combat acidification, the EU Commission has produced a Community strategy, which is based on the concept of critical loads. The DGMK report 548 deals with this concept of critical loads and with the measures to combat soil acidifiction. It explains that critical loads are not damage thresholds, but environmental standards, and deviation does not necessarily required any action. It demonstrates, why the reduction of sulphur dioxide emissions, formed during the utilization of fluid fuels, is not a cost-effective measures. It proposes continued implementation of agreed plans for emission reduction, before additional legislative steps are considered. This report contains information to June 1998 inclusive. (orig.) [Deutsch] Die Entstehung der sogenannten `neuartigen Waldschaeden` fuehrt man zum Teil auf die Einwirkung gewisser Luftschadstoffe wie Schwefel- und Stickoxide zurueck, die als saurer Regen auf die Erde niedergehen und zu einer Versauerung des Bodens und damit zu einer Schaedigung empfindlicher Oekosysteme wie der Waelder fuehren koennen. Die EU-Kommission hat eine Strategie der EU zur Bekaempfung dieser Versauerung entwickelt, die auf dem Konzept der kritischen Belastungen beruht. Der DGMK-Bericht 548 setzt sich mit diesem Konzept der kritischen Belastungen sowie mit den Massnahmen zur Bekaempfung der Bodenversauerung auseinander. Er erlaeutert, dass kritische Belastungen keinen Schwellenwert, sondern einen Umweltstandard darstellen, aus dessen Ueberschreitung nicht zwingend ein Handlungsbedarf abgeleitet werden kann. Er erlaeutert ferner, warum vor allem die Reduktion der Schwefeldioxidemissionen, die beim Einsatz fluessiger Kraft- und Brennstoffe entstehen, keine

  20. MCNP calculation of the critical H_3BO_3 concentrations for the first fuel loading into the reactor core of NPP MO-3-4 units

    International Nuclear Information System (INIS)

    Vrban, B.; Lueley, J.; Farkas, G.; Hascik, J.; Hinca, R.; Petriska, M.; Slugen, V.

    2012-01-01

    The purpose of the analysis was the determination of critical H_3BO_3 concentrations for the first fuel loading into the reactor core of MO34 units using 2"n"d generation fuel during the first start-up of new unit using calculation code MCNP 1.60. H_3BO_3 concentrations were computed for the given temperature of the primary circuit and position of the 6"t"h safety control rod group. Because of the very first start-up of these units, detailed analyses of active-core parameters are required by National Regulatory Authority and needed for safe operation of nuclear facility. (authors)

  1. Application of a loading dose of colistin methanesulfonate in critically ill patients: population pharmacokinetics, protein binding, and prediction of bacterial kill.

    Science.gov (United States)

    Mohamed, Ami F; Karaiskos, Ilias; Plachouras, Diamantis; Karvanen, Matti; Pontikis, Konstantinos; Jansson, Britt; Papadomichelakis, Evangelos; Antoniadou, Anastasia; Giamarellou, Helen; Armaganidis, Apostolos; Cars, Otto; Friberg, Lena E

    2012-08-01

    A previous pharmacokinetic study on dosing of colistin methanesulfonate (CMS) at 240 mg (3 million units [MU]) every 8 h indicated that colistin has a long half-life, resulting in insufficient concentrations for the first 12 to 48 h after initiation of treatment. A loading dose would therefore be beneficial. The aim of this study was to evaluate CMS and colistin pharmacokinetics following a 480-mg (6-MU) loading dose in critically ill patients and to explore the bacterial kill following the use of different dosing regimens obtained by predictions from a pharmacokinetic-pharmacodynamic model developed from an in vitro study on Pseudomonas aeruginosa. The unbound fractions of colistin A and colistin B were determined using equilibrium dialysis and considered in the predictions. Ten critically ill patients (6 males; mean age, 54 years; mean creatinine clearance, 82 ml/min) with infections caused by multidrug-resistant Gram-negative bacteria were enrolled in the study. The pharmacokinetic data collected after the first and eighth doses were analyzed simultaneously with the data from the previous study (total, 28 patients) in the NONMEM program. For CMS, a two-compartment model best described the pharmacokinetics, and the half-lives of the two phases were estimated to be 0.026 and 2.2 h, respectively. For colistin, a one-compartment model was sufficient and the estimated half-life was 18.5 h. The unbound fractions of colistin in the patients were 26 to 41% at clinical concentrations. Colistin A, but not colistin B, had a concentration-dependent binding. The predictions suggested that the time to 3-log-unit bacterial kill for a 480-mg loading dose was reduced to half of that for the dose of 240 mg.

  2. Multiscale Framework for Assessing Critical Loads of Atmospheric Nitrogen Deposition for Aquatic Ecosystems in Wilderness Areas of the Western United States

    Science.gov (United States)

    Nanus, Leora; Clow, David; Saros, Jasmine; McMurray, Jill; Blett, Tamara; Sickman, James

    2017-04-01

    High-elevation aquatic ecosystems in Wilderness areas of the western United States are impacted by current and historic atmospheric nitrogen (N) deposition associated with local and regional air pollution. Documented effects include elevated surface water nitrate concentrations, increased algal productivity, and changes in diatom species assemblages. A predictive framework was developed for sensitive high-elevation basins across the western United States at multiple spatial scales including the Rocky Mountain Region (Rockies), the Greater Yellowstone Area (GYA), and Yosemite (YOSE) and Sequoia & Kings Canyon (SEKI) National Parks. Spatial trends in critical loads of N deposition for nutrient enrichment of aquatic ecosystems were quantified and mapped using a geostatistical approach, with modeled N deposition, topography, vegetation, geology, and climate as potential explanatory variables. Multiple predictive models were created using various combinations of explanatory variables; this approach allowed for better quantification of uncertainty and identification of areas most sensitive to high atmospheric N deposition (> 3 kg N ha-1 yr-1). For multiple spatial scales, the lowest critical loads estimates (1.5 + 1 kg N ha-1 yr-1) correspond with areas of high N deposition and vary spatially ranging from less than 20% to over 40% of the study area for the Rockies, GYA, YOSE, and SEKI. These predictive models and maps identify sensitive aquatic ecosystems that may be impacted by excess atmospheric N deposition and can be used to help protect against future anthropogenic disturbance. The approach presented here may be transferable to other remote and protected high-elevation ecosystems at multiple spatial scales that are sensitive to adverse effects of pollutant loading in the US and around the world.

  3. Critical solvent properties affecting the particle formation process and characteristics of celecoxib-loaded plga microparticles via spray-drying.

    Science.gov (United States)

    Wan, Feng; Bohr, Adam; Maltesen, Morten Jonas; Bjerregaard, Simon; Foged, Camilla; Rantanen, Jukka; Yang, Mingshi

    2013-04-01

    It is imperative to understand the particle formation mechanisms when designing advanced nano/microparticulate drug delivery systems. We investigated how the solvent power and volatility influence the texture and surface chemistry of celecoxib-loaded poly (lactic-co-glycolic acid) (PLGA) microparticles prepared by spray-drying. Binary mixtures of acetone and methanol at different molar ratios were applied to dissolve celecoxib and PLGA prior to spray-drying. The resulting microparticles were characterized with respect to morphology, texture, surface chemistry, solid state properties and drug release profile. The evaporation profiles of the feed solutions were investigated using thermogravimetric analysis (TGA). Spherical PLGA microparticles were obtained, irrespectively of the solvent composition. The particle size and surface chemistry were highly dependent on the solvent power of the feed solution. An obvious burst release was observed for the microparticles prepared by the feed solutions with the highest amount of poor solvent for PLGA. TGA analysis revealed distinct drying kinetics for the binary mixtures. The particle formation process is mainly governed by the PLGA precipitation rate, which is solvent-dependent, and the migration rate of celecoxib molecules during drying. The texture and surface chemistry of the spray-dried PLGA microparticles can therefore be tailored by adjusting the solvent composition.

  4. The effect of transverse loads up to 300 MPa on the critical currents of Nb3Sn cables

    International Nuclear Information System (INIS)

    Boschman, H.; Verweij, A.P.; Wessel, S.; ten Kate, H.H.J.; van de Klundert, L.J.M.

    1991-01-01

    In the framework of the development of an experimental 10 T Nb 3 Sn dipole coil for the LHC at CERN the effects of transverse stress on Rutherford type of Nb 3 Sn cables have been investigated. For this purpose a special facility was designed and taken into operation in which the voltage-current behavior of short pieces of Nb 3 Sn cables can be investigated in a background field up to 11 T and an applied stress of 300 MPa. The repulsive Lorentz force of 250 kN, generated by a set of superconducting coils, is used to impress the cable over an area of 20 x 42 mm 2 maximum, in presence of a transport current up to 40 kA. In this paper the testing equipment is described and the first results of the observed critical current degradation of two Nb 3 Sn cables are discussed

  5. Enabling the Distributed Generation Market of High Temperature Fuel Cell and Absorption Chiller Systems to Support Critical and Commercial Loads

    Science.gov (United States)

    DiMola, Ashley M.

    Buildings account for over 18% of the world's anthropogenic Greenhouse Gas (GHG) emissions. As a result, a technology that can offset GHG emissions associated with buildings has the potential to save over 9 Giga-tons of GHG emissions per year. High temperature fuel cell and absorption chiller (HTFC/AC) technology offers a relatively low-carbon option for meeting cooling and electric loads for buildings while producing almost no criteria pollutants. GHG emissions in the state of California would decrease by 7.48 million metric tons per year if every commercial building in the State used HTFC/AC technology to meet its power and cooling requirements. In order to realize the benefits of HTFC/AC technology on a wide scale, the distributed generation market needs to be exposed to the technology and informed of its economic viability and real-world potential. This work characterizes the economics associated with HTFC/AC technology using select scenarios that are representative of realistic applications. The financial impacts of various input factors are evaluated and the HTFC/AC simulations are compared to the economics of traditional building utilities. It is shown that, in addition to the emissions reductions derived from the systems, HTFC/AC technology is financially preferable in all of the scenarios evaluated. This work also presents the design of a showcase environment, centered on a beta-test application, that presents (1) system operating data gathered using a custom data acquisition module, and (2) HTFC/AC technology in a clear and approachable manner in order to serve the target audience of market stakeholders.

  6. Computational methods for predicting the response of critical as-built infrastructure to dynamic loads (architectural surety)

    Energy Technology Data Exchange (ETDEWEB)

    Preece, D.S.; Weatherby, J.R.; Attaway, S.W.; Swegle, J.W.; Matalucci, R.V.

    1998-06-01

    Coupled blast-structural computational simulations using supercomputer capabilities will significantly advance the understanding of how complex structures respond under dynamic loads caused by explosives and earthquakes, an understanding with application to the surety of both federal and nonfederal buildings. Simulation of the effects of explosives on structures is a challenge because the explosive response can best be simulated using Eulerian computational techniques and structural behavior is best modeled using Lagrangian methods. Due to the different methodologies of the two computational techniques and code architecture requirements, they are usually implemented in different computer programs. Explosive and structure modeling in two different codes make it difficult or next to impossible to do coupled explosive/structure interaction simulations. Sandia National Laboratories has developed two techniques for solving this problem. The first is called Smoothed Particle Hydrodynamics (SPH), a relatively new gridless method comparable to Eulerian, that is especially suited for treating liquids and gases such as those produced by an explosive. The SPH capability has been fully implemented into the transient dynamics finite element (Lagrangian) codes PRONTO-2D and -3D. A PRONTO-3D/SPH simulation of the effect of a blast on a protective-wall barrier is presented in this paper. The second technique employed at Sandia National Laboratories uses a relatively new code called ALEGRA which is an ALE (Arbitrary Lagrangian-Eulerian) wave code with specific emphasis on large deformation and shock propagation. ALEGRA is capable of solving many shock-wave physics problems but it is especially suited for modeling problems involving the interaction of decoupled explosives with structures.

  7. Determination and Distribution of Critical Loads: Application to the Forest Soils in the Autonomous Region of Madrid; Determinacion y Distribucion de Cargas Criticas: Aplicacion a los Suelos forestales de la comunidad Autonoma de Madrid

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, M.; Schmid, T.; Rabago, I. [Ciemat, Madrid (Spain)

    2000-07-01

    The critical loads of acidity and sulphur have been determined for forest soils within the north and north-west of the Autonomous Region of Madrid. The SMB-CCE and SMB-PROFILE Steady state models have been applied using a 1 km x 1 km resolution. the forest ecosystems have been characterised according to the soil and forest type, slope and climatic data using a Geographic Information System. In order to estimate the critical loads, processes such as weathering rate of the parent material, atmospheric deposition, critical alkalinity leaching rate and nutrients absorbed by the vegetation have been considered. In general the forest soils present high critical load values for acidity and sulphur. The more sensitive zones are found in the north of the Sierra of Guadarrama. Independent of the applied methods, the results are associated to the types of soils where Leptosols have the lowest. Cambisoles and Regosoles intermediate and luvisoles the most elevated values. (Author) 40 refs.

  8. On-line Scheduling Of Multi-Server Batch Operations

    NARCIS (Netherlands)

    van der Zee, D.J.; van Harten, A.; Schuur, P.C.

    1999-01-01

    Batching jobs in a manufacturing system is a very common policy in most industries. Main reasons for batching are avoidance of setups and/or facilitation of material handling. Good examples of batch-wise production systems are ovens found in aircraft industry and in semiconductor manufacturing.

  9. On-line scheduling of multi-server batch operations

    NARCIS (Netherlands)

    Zee, Durk Jouke van der; Harten, Aart van; Schuur, Peter

    The batching of jobs in a manufacturing system is a very common policy in many industries. The main reasons for batching are the avoidance of setups and/or facilitation of material handling. Good examples of batch-wise production systems are the ovens that are found in the aircraft industry and in

  10. Analysis of a multi-server queueing model of ABR

    Directory of Open Access Journals (Sweden)

    R. Núñez-Queija

    1998-01-01

    Full Text Available In this paper we present a queueing model for the performance analysis of Available Bit Rate (ABR traffic in Asynchronous Transfer Mode (ATM networks. We consider a multi-channel service station with two types of customers, denoted by high priority and low priority customers. In principle, high priority customers have preemptive priority over low priority customers, except on a fixed number of channels that are reserved for low priority traffic. The arrivals occur according to two independent Poisson processes, and service times are assumed to be exponentially distributed. Each high priority customer requires a single server, whereas low priority customers are served in processor sharing fashion. We derive the joint distribution of the numbers of customers (of both types in the system in steady state. Numerical results illustrate the effect of high priority traffic on the service performance of low priority traffic.

  11. Analysis of a multi-server queueing model of ABR

    NARCIS (Netherlands)

    R. Núñez Queija (Rudesindo); O.J. Boxma (Onno)

    1996-01-01

    textabstractIn this paper we present a queueing model for the performance a-na-ly-sis of ABR traffic in ATM networks. We consider a multi-channel service station with two types of customers, the first having preemptive priority over the second. The arrivals occur according to two independent Poisson

  12. Steady-state sulfur critical loads and exceedances for protection of aquatic ecosystems in the U.S. Southern Appalachian Mountains.

    Science.gov (United States)

    McDonnell, Todd C; Sullivan, Timothy J; Hessburg, Paul F; Reynolds, Keith M; Povak, Nicholas A; Cosby, Bernard J; Jackson, William; Salter, R Brion

    2014-12-15

    Atmospherically deposited sulfur (S) causes stream water acidification throughout the eastern U.S. Southern Appalachian Mountain (SAM) region. Acidification has been linked with reduced fitness and richness of aquatic species and changes to benthic communities. Maintaining acid-base chemistry that supports native biota depends largely on balancing acidic deposition with the natural resupply of base cations. Stream water acid neutralizing capacity (ANC) is maintained by base cations that mostly originate from weathering of surrounding lithologies. When ambient atmospheric S deposition exceeds the critical load (CL) an ecosystem can tolerate, stream water chemistry may become lethal to biota. This work links statistical predictions of ANC and base cation weathering for streams and watersheds of the SAM region with a steady-state model to estimate CLs and exceedances. Results showed that 20.1% of the total length of study region streams displayed ANC high elevation, and cool and moist forested conditions, the percentage of stream length in exceedance was highest for mountain wilderness areas and in national parks, and lowest for privately owned valley bottom land. Exceedance results were summarized by 12-digit hydrologic unit code (subwatershed) for use in developing management goals and policy objectives, and for long-term monitoring. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Data on respiratory variables in critically ill patients with acute respiratory failure placed on proportional assist ventilation with load adjustable gain factors (PAV+

    Directory of Open Access Journals (Sweden)

    Dimitris Georgopoulos

    2016-09-01

    Full Text Available The data show respiratory variables in 108 critically ill patients with acute respiratory failure placed on proportional assist ventilation with load adjustable gain factors (PAV+ after at least 36 h on passive mechanical ventilation. PAV+ was continued for 48 h until the patients met pre-defined criteria either for switching to controlled modes or for breathing without ventilator assistance. Data during passive mechanical ventilation and during PAV+ are reported. Data are acquired from the whole population, as well as from patients with and without acute respiratory distress syndrome. The reported variables are tidal volume, driving pressure (ΔP, the difference between static end-inspiratory plateau pressure and positive end-expiratory airway pressure, respiratory system compliance and resistance, and arterial blood gasses. The data are supplemental to our original research article, which described individual ΔP in these patients and examined how it related to ΔP when the same patients were ventilated with passive mechanical ventilation using the currently accepted lung-protective strategy “Driving pressure during assisted mechanical ventilation. Is it controlled by patient brain?” [1]. Keywords: Tidal volume, Compliance, Driving pressure

  14. Critical load of acid precipitations. Mapping of Italian regions; Mappa dei carichi critici di acidita' totale riferita al territorio italiano

    Energy Technology Data Exchange (ETDEWEB)

    Bonanni, P.; Brini, S.; Delmonaco, G.; Liburdi, R.; Trocciola, A.; Vetrella, G. [ENEA Centro Ricerche Casaccia, S. Maria di Galeria, RM (Italy). Dipt. Ambiente

    1999-07-01

    In this report the mapping of critical loads of acidity for the Italian terrestrial ecosystems is presented. The level O method (Stockholm Environment Institute) has been used to determine sensitivity to acid deposition; this semi-quantitative method has been modified to address some Italian characteristics. The results show that the sensitivity of the Italian soils to acidification is not particularly elevated: there are really only few small areas with poor tolerance to acid depositions. These areas are in the north-east of Italy, in Alpine and Prealpine region. [Italian] Nel rapporto vengono riportati i risultati della mappatura, riferita agli ecosistemi terrestri del territorio italiano, dei carichi critici per l'acidita' totale. Il calcolo dei carichi critici e' stato eseguito sulla base della metodologia messa a punto dallo Stokholm Environment Institute; a questo metodo semi-quantitativo sono state apportate alcune modifiche per meglio adattarlo alle caratteristiche del territorio italiano. Dall'analisi dei risultati ottenuti, si evince come la sensibilita' dei suoli italiani all'acidificazione non sia particolarmente elevata: sono state riscontrate infatti solo alcune aree, peraltro con superficie limitata, con una scarsa tolleranza alle deposizioni acide. Tali aree sono localizzate nell'Italia nord-orientale, in zona alpina e prealpina.

  15. Mapping of critical loads of acidity for the Italian terrestrial ecosystems; Mappa dei carichi critici di acidita' totale riferita al territorio italiano

    Energy Technology Data Exchange (ETDEWEB)

    Bonanni, P.; Brini, S.; Delmonaco, G.; Liburdi, C.; Trocciola, A.; Vetrella, G. [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dipt. Ambiente

    1999-07-01

    In this report the mapping of critical loads of acidity for the Italian terrestrial ecosystems is presented. The level 0 method (Stockholm Environment Institute) has been used to determine sensitivity to acid deposition; this semi-quantitative method has been modified to address some Italian characteristics. The sensitivity of the Italian soils to acidification is not particularly elevated: there are really only few small areas with poor tolerance to acid depositions in the north-east Italy, Alpine and Prealpine region. [Italian] Nel presente relazione vengono riportati i risultati della mappatura riferita ad ecosistemi terrestri del territorio italiano, dei carichi critici per l'acidita' totale. Il calcolo dei carichi e' stato eseguito sulla base della metodologia messa a punto dallo Stockholm Environment Institute con alcune modifiche per adattarlo meglio alle caratteristiche del territorio italiano. Si dimostra che la sensibilita' dei suoli italiani all'acidificazione non sia particolarmente elevata: sono state riscontrate infatti solo alcune aree, peraltro con superficie limitata, con una scarsa tolleranza alle deposizioni acide nelle zone del Nord Est, in zona alpina e prealpina.

  16. Efficacy and Safety of a Colistin Loading Dose, High-Dose Maintenance Regimen in Critically Ill Patients With Multidrug-Resistant Gram-Negative Pneumonia.

    Science.gov (United States)

    Elefritz, Jessica L; Bauer, Karri A; Jones, Christian; Mangino, Julie E; Porter, Kyle; Murphy, Claire V

    2017-09-01

    Emergence of multidrug-resistant (MDR) gram-negative (GN) pathogens and lack of novel antibiotics have increased the use of colistin, despite unknown optimal dosing. This study aimed to evaluate the safety and efficacy of a colistin loading dose, high-dose (LDHD) maintenance regimen in patients with MDR-GN pneumonia. A retrospective cohort analysis was performed comparing critically ill patients with MDR-GN pneumonia pre- and postimplementation of a colistin LDHD guideline with a primary outcome of clinical cure. Safety was assessed using incidence of acute kidney injury (AKI) based on RIFLE (risk, injury, failure, loss, end-stage renal disease) criteria. Seventy-two patients met the inclusion criteria (42 preimplementation and 30 postimplementation). Clinical cure was achieved in 23 (55%) patients in the preimplementation group and 20 (67%) patients in the postimplementation group ( P = .31). AKI occurred in 50% of the patients during the preimplementation period and 58% during the postimplementation period ( P = .59) with no difference in initiation rates of renal replacement therapy. The increased clinical cure rate after implementation of the colistin LDHD guideline did not reach statistical significance. The LDHD guideline, however, was not associated with an increased incidence of AKI, despite higher intravenous colistin doses. Opportunity exists to optimize colistin dosage while balancing toxicity, but larger studies are warranted.

  17. Dynamic stability under sudden loads

    International Nuclear Information System (INIS)

    Simitses, G.J.

    1998-01-01

    The concept of dynamic stability of elastic structures subjected to sudden (step) loads is discussed. The various criteria and related methodologies for estimating critical conditions are presented with the emphasis on their similarities and differences. These are demonstrated by employing a simple mechanical model. Several structural configurations are analyzed, for demonstration purposes, with the intention of comparing critical dynamic loads to critical static loads. These configurations include shallow arches and shallow spherical caps, two bar frames, and imperfect cylindrical shells of metallic as well as laminated composite construction. In the demonstration examples, the effect of static pre loading on the dynamic critical load is presented

  18. On delay adjustment for dynamic load balancing in distributed virtual environments.

    Science.gov (United States)

    Deng, Yunhua; Lau, Rynson W H

    2012-04-01

    Distributed virtual environments (DVEs) are becoming very popular in recent years, due to the rapid growing of applications, such as massive multiplayer online games (MMOGs). As the number of concurrent users increases, scalability becomes one of the major challenges in designing an interactive DVE system. One solution to address this scalability problem is to adopt a multi-server architecture. While some methods focus on the quality of partitioning the load among the servers, others focus on the efficiency of the partitioning process itself. However, all these methods neglect the effect of network delay among the servers on the accuracy of the load balancing solutions. As we show in this paper, the change in the load of the servers due to network delay would affect the performance of the load balancing algorithm. In this work, we conduct a formal analysis of this problem and discuss two efficient delay adjustment schemes to address the problem. Our experimental results show that our proposed schemes can significantly improve the performance of the load balancing algorithm with neglectable computation overhead.

  19. Accumulation of nitrogen - a critical parameter for the calculation of load limits from nitrogen in forests; Akkumulering av nitrogen - en kritisk parameter for beregning av taalegrenser for nitrogen i skog

    Energy Technology Data Exchange (ETDEWEB)

    Sogn, T A; Stuanes, A O; Abrahamsen, G

    1996-01-01

    The conference paper deals with the accumulation of nitrogen in forests in Norway. The level of accumulation is a critical factor for the calculation of load limits. The paper compares the average rapidity values of accumulation since the last glacial age with the calculated values from the more short-lasting period based on data from surveying programs of the State Pollution Control Authority, manuring experiments, and other relevant research programs in this field. 8 refs., 1 fig., 1 tab.

  20. Influence of the constant load sintering on the improvement of the transport critical current in Ag-(Bi,Pb)[sub 2]Sr[sub 2]Ca[sub 2]Cu[sub 3]O[sub x] tape form conductor

    Energy Technology Data Exchange (ETDEWEB)

    Jackiewicz, J [IRC in Superconductivity, Univ. of Cambridge (United Kingdom); Glowacki, B A [IRC in Superconductivity, Univ. of Cambridge (United Kingdom) Dept. of Materials Science and Metallurgy, Univ. of Cambridge (United Kingdom)

    1993-05-10

    The effects of the short time, low value constant load pressing process of cold rolled silver clad wires conducted at temperatures close to the partial melting point of the ceramic core, from 800 C to 866 C on the microstructure and critical current anisotropy have been studied in detail. The strong influence of the constant load sintering at up to 2 MPa for 1 hour on the improvement of the alignment of the ceramic core in the tape form conductors was confirmred by microstructure investigations and also by the I[sub c] versus [mu][sub 0]H measurements. The magnetic field dependence of the transport critical current, for [mu][sub 0]H parallel to the surface of the tape and also for [mu][sub 0]H perpendicular to the surface of the tape, is very significantly reduced in the tapes sintered under constant load. The analysis of the mechanical creep of silver and ceramic core versus temperature allowed us to optimise the densification conditions of the investigated single core Ag-''2223'' tape form conductor for the load used. (orig.)

  1. Epitope specificity is critical for high and moderate avidity cytotoxic T lymphocytes associated with control of viral load and clinical disease in horses with equine infectious anemia virus

    International Nuclear Information System (INIS)

    Mealey, Robert H.; Zhang Baoshan; Leib, Steven R.; Littke, Matt H.; McGuire, Travis C.

    2003-01-01

    Equine infectious anemia virus (EIAV) is a lentivirus that causes persistent infections in horses. We hypothesized that high-avidity CTL specific for nonvariable epitopes might be associated with low viral load and minimal disease in EIAV-infected horses. To test this hypothesis, memory CTL (CTLm) responses were analyzed in two infected horses with high plasma viral loads and recurrent disease (progressors), and in two infected horses with low-to-undetectable viral loads and mild disease (nonprogressors). High-avidity CTLm in one progressor recognized an envelope gp90 epitope, and the data documented for the first time in EIAV that viral variation led to CTL escape. Each of the nonprogressors had high-to-moderate avidity CTLm directed against epitopes within Rev, including the nuclear export and nuclear localization domains. These results suggested that the epitope specificity of high- and moderate-avidity CTLm was an important determinant for disease outcome in the EIAV-infected horses examined

  2. Determinación de las propiedades físicas y carga crítica del aceite vegetal Jatropha curcas L // Determination of physical properties and critical load of Jatropha curcas L vegetable oil

    Directory of Open Access Journals (Sweden)

    Calixto Rodríguez-Martínez

    2012-09-01

    Full Text Available En el trabajo se determinaron las propiedades físicas y la carga critica del aceite de Jatropha curcas L, obtenido de las plantas cultivadas en la provincia de Guantánamo en Cuba. Estas propiedades fueron comparadas con las propiedades de otros aceites vegetales (aceite ricino, aceite de girasol, aceite de colza y aceite de soya usados como biolubricantes. Los resultados mostraron que las propiedades físicas del aceite de Jatropha curcas L fueron similares a la mayoría de los aceites vegetales. La carga crítica del aceite de la Jatropha curcas L ocupa una posición intermedia entre el aceite ricino y los aceites de girasol, colza y soya, lo cual permite asegurar que el aceite de Jatropha curcas L es un buen candidato para como biolubricante.Palabras claves: biolubricantes, aceites vegetales, Jatropha curcas L, propiedades físicas, carga crítica._______________________________________________________________________________AbstractIn this paper the physical properties and the critical load of the Jatropha curcas L oil, plantations located in Guantanamo province, Cuba were determined. These properties together with other vegetable oils (castor, sunflower, rapeseed and soybean oils used as biolubricant were compared. These results have showed that the physical properties of the Jatropha curcas L oil were similar to most of vegetable oils.The critical load of Jatropha curcas oil has an intermediate position just castor oil and sunflower, rapeseed and soybean oils. Jatropha curcas oil has good potential as the renewable energy as well as biolubricant feedstock.Key words: biolubricants, vegetable oils, Jatropha curcas L, physical properties, critical load.

  3. Electrical load modeling

    Energy Technology Data Exchange (ETDEWEB)

    Valgas, Helio Moreira; Pinto, Roberto del Giudice R.; Franca, Carlos [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil); Lambert-Torres, Germano; Silva, Alexandre P. Alves da; Pires, Robson Celso; Costa, Junior, Roberto Affonso [Escola Federal de Engenharia de Itajuba, MG (Brazil)

    1994-12-31

    Accurate dynamic load models allow more precise calculations of power system controls and stability limits, which are critical mainly in the operation planning of power systems. This paper describes the development of a computer program (software) for static and dynamic load model studies using the measurement approach for the CEMIG system. Two dynamic load model structures are developed and tested. A procedure for applying a set of measured data from an on-line transient recording system to develop load models is described. (author) 6 refs., 17 figs.

  4. How does variability in input load relate to the probability of critically delayed delivery in a simple Multipart Re-entrant Flow-line problem?

    DEFF Research Database (Denmark)

    Nielsen, Erland Hejn

    2003-01-01

    of the estimation of the probability of critically delayed delivery beyond a specified threshold value given a certain production batch size and try to establish a relation to certain parameters that can be linked to the degree of regularity of the arrival stream of parts to the job/flow-shop. This last aspect...... relates remotely to the Lean Thinking philosophy that praises the smooth and uninterrupted production flow to be beneficial to the overall operation of productive plants in general, and we will link our findings to this discussion as well....

  5. Load forecasting

    International Nuclear Information System (INIS)

    Mak, H.

    1995-01-01

    Slides used in a presentation at The Power of Change Conference in Vancouver, BC in April 1995 about the changing needs for load forecasting were presented. Technological innovations and population increase were said to be the prime driving forces behind the changing needs in load forecasting. Structural changes, market place changes, electricity supply planning changes, and changes in planning objectives were other factors discussed. It was concluded that load forecasting was a form of information gathering, that provided important market intelligence

  6. CriticalEd

    DEFF Research Database (Denmark)

    Kjellberg, Caspar Mølholt; Meredith, David

    2014-01-01

    . Since the comments are not input sequentially, with regard to position, but in arbitrary order, this list must be sorted by copy/pasting the rows into place—an error-prone and time-consuming process. Scholars who produce critical editions typically use off-the-shelf music notation software......The best text method is commonly applied among music scholars engaged in producing critical editions. In this method, a comment list is compiled, consisting of variant readings and editorial emendations. This list is maintained by inserting the comments into a document as the changes are made......, consisting of a Sibelius plug-in, a cross-platform application, called CriticalEd, and a REST-based solution, which handles data storage/retrieval. A prototype has been tested at the Danish Centre for Music Publication, and the results suggest that the system could greatly improve the efficiency...

  7. Beam loading

    OpenAIRE

    Boussard, Daniel

    1987-01-01

    We begin by giving a description of the radio-frequency generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, radio-frequency feedback and feedforward are described. Examples of digital radio-frequency phase and amplitude control for the special case of superco...

  8. Aeroelastic tailoring for gust load alleviation

    NARCIS (Netherlands)

    Lancelot, P.M.G.J.; De Breuker, R.

    2016-01-01

    This paper presents the results from the equivalent static load method applied to gust response optimisation of an aircraft wing. Through the different optimisation runs, it is assessed that gust load cases can be critical and are difficult to constrain with the sole use of static load cases.

  9. Opposite Effects of Capacity Load and Resolution Load on Distractor Processing

    OpenAIRE

    Zhang, Weiwei; Luck, Steven J.

    2014-01-01

    According to the load theory of attention, an increased perceptual load reduces distractor processing whereas an increased working memory load facilitates distractor processing. Here we raise the possibility that the critical distinction may instead be between an emphasis on resolution and an emphasis on capacity. That is, perceptual load manipulations typically emphasize resolution (fine-grained discriminations), whereas working memory load manipulations typically emphasize capacity (simulta...

  10. Beam loading

    CERN Document Server

    Gamp, Alexander

    2013-01-01

    We begin by giving a description of the radio-frequency generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, radio-frequency feedback and feedforward are described. Examples of digital radio-frequency phase and amplitude control for the special case of superconducting cavities are also given. Finally, a dedicated phase loop for damping synchrotron oscillations is discussed.

  11. Beam loading

    International Nuclear Information System (INIS)

    Gamp, Alexander

    2013-01-01

    We begin by giving a description of the radio-frequency generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, radio-frequency feedback and feedforward are described. Examples of digital radio-frequency phase and amplitude control for the special case of superconducting cavities are also given. Finally, a dedicated phase loop for damping synchrotron oscillations is discussed. (author)

  12. Load sensor

    NARCIS (Netherlands)

    Van den Ende, D.; Almeida, P.M.R.; Dingemans, T.J.; Van der Zwaag, S.

    2007-01-01

    The invention relates to a load sensor comprising a polymer matrix and a piezo-ceramic material such as PZT, em not bedded in the polymer matrix, which together form a compos not ite, wherein the polymer matrix is a liquid crystalline resin, and wherein the piezo-ceramic material is a PZT powder

  13. Carbohydrate Loading.

    Science.gov (United States)

    Csernus, Marilyn

    Carbohydrate loading is a frequently used technique to improve performance by altering an athlete's diet. The objective is to increase glycogen stored in muscles for use in prolonged strenuous exercise. For two to three days, the athlete consumes a diet that is low in carbohydrates and high in fat and protein while continuing to exercise and…

  14. Load sensor

    OpenAIRE

    Van den Ende, D.; Almeida, P.M.R.; Dingemans, T.J.; Van der Zwaag, S.

    2007-01-01

    The invention relates to a load sensor comprising a polymer matrix and a piezo-ceramic material such as PZT, em not bedded in the polymer matrix, which together form a compos not ite, wherein the polymer matrix is a liquid crystalline resin, and wherein the piezo-ceramic material is a PZT powder forming 30-60% by volume of the composite, and wherein the PZT powder forms 40-50% by volume of the composite.

  15. Thinking Critically about Critical Thinking

    Science.gov (United States)

    Mulnix, Jennifer Wilson

    2012-01-01

    As a philosophy professor, one of my central goals is to teach students to think critically. However, one difficulty with determining whether critical thinking can be taught, or even measured, is that there is widespread disagreement over what critical thinking actually is. Here, I reflect on several conceptions of critical thinking, subjecting…

  16. Characterizing and Managing Intrusion Detection System (IDS) Alerts with Multi-Server/Multi-Priority Queuing Theory

    Science.gov (United States)

    2014-12-26

    administrators dashboard , so that they can be effectively triaged, analyzed, and used to implement defensive actions to keep the network safe and...For the bank teller, some customers will require straight forward services (a quick deposit or cashing a check) while others will have questions or

  17. Dynamic job assignment heuristics for multi-server batch operations - A cost-based approach

    NARCIS (Netherlands)

    Zee, D.J. van der; Harten, A. van; Schuur, P.C.

    1997-01-01

    In many industries production facilities are used which process products in a batch-wise manner. Guided by research in the aircraft industry, where the process of hardening synthetic aircraft parts was studied, we propose a new control strategy for these types of systems. Given the availability of

  18. Dynamic Job Assignment Heuristics For Multi-server Batch Operations : A Cost-based Approach

    NARCIS (Netherlands)

    van der Zee, D.J.; van Harten, A.; Schuur, P.C.

    1996-01-01

    In many industries production facilities are used which process products in a batch-wise manner. Guided by research in aircraft industry, where the process of hardening synthetic aircraft parts was studied, we evaluate a new control strategy for these type of systems. Given the availability of

  19. Real-time adaptive control of multi-product multi-server bulk service processes

    NARCIS (Netherlands)

    van der Zee, D.J.

    2001-01-01

    Batching jobs in a manufacturing system is a very common policy in most industries. Main reasons for batching are avoidance of setups and/or facilitation of material handling. Batch processing systems often consist of multiple machines of different types for the range and volumes of products that

  20. A numerical solution for the multi-server queue with hyper-exponential service times

    NARCIS (Netherlands)

    de Smit, J.H.A.

    1983-01-01

    In this paper we present a numerical method for the queue GI/H2/s, which is based on general results for GI/Hm/s. We give a complete description of the algorithm which yields exact results for the steady distributions of the actual waiting time, the virtual waiting time and the number of customers

  1. Scheduling of multi-class multi-server queueing systems with abandonments

    Czech Academy of Sciences Publication Activity Database

    Ayesta, U.; Jacko, P.; Novák, Vladimír

    2017-01-01

    Roč. 20, č. 2 (2017), s. 129-145 ISSN 1094-6136 R&D Projects: GA MŠk(CZ) SVV260475 Institutional support: Progres-Q24 Keywords : stochastic scheduling * abandonment * restless bandits Subject RIV: AH - Economics OBOR OECD: Economic Theory Impact factor: 1.281, year: 2016

  2. Critical Care

    Science.gov (United States)

    Critical care helps people with life-threatening injuries and illnesses. It might treat problems such as complications from surgery, ... attention by a team of specially-trained health care providers. Critical care usually takes place in an ...

  3. How Critical Is Critical Thinking?

    Science.gov (United States)

    Shaw, Ryan D.

    2014-01-01

    Recent educational discourse is full of references to the value of critical thinking as a 21st-century skill. In music education, critical thinking has been discussed in relation to problem solving and music listening, and some researchers suggest that training in critical thinking can improve students' responses to music. But what exactly is…

  4. Accommodating oversize and overweight loads : technical report.

    Science.gov (United States)

    2012-07-01

    Adequate management of oversize/overweight (OS/OW) permit loads throughout the state of Texas is : critical to maintaining a vibrant state economy. The growth in the number and size of permit loads in recent : years is clear evidence that new tools a...

  5. Load testing circuit

    DEFF Research Database (Denmark)

    2009-01-01

    A load testing circuit a circuit tests the load impedance of a load connected to an amplifier. The load impedance includes a first terminal and a second terminal, the load testing circuit comprising a signal generator providing a test signal of a defined bandwidth to the first terminal of the load...

  6. Critical Jostling

    Directory of Open Access Journals (Sweden)

    Pippin Barr

    2016-11-01

    Full Text Available Games can serve a critical function in many different ways, from serious games about real world subjects to self-reflexive commentaries on the nature of games themselves. In this essay we discuss critical possibilities stemming from the area of critical design, and more specifically Carl DiSalvo’s adversarial design and its concept of reconfiguring the remainder. To illustrate such an approach, we present the design and outcomes of two games, Jostle Bastard and Jostle Parent. We show how the games specifically engage with two previous games, Hotline Miami and Octodad: Dadliest Catch, reconfiguring elements of those games to create interactive critical experiences and extensions of the source material. Through the presentation of specific design concerns and decisions, we provide a grounded illustration of a particular critical function of videogames and hope to highlight this form as another valuable approach in the larger area of videogame criticism.

  7. Critical Proximity

    OpenAIRE

    Simon, Jane

    2010-01-01

    This essay considers how written language frames visual objects. Drawing on Michel Foucault’s response to Raymond Roussel’s obsessive description, the essay proposes a model of criticism where description might press up against its objects. This critical closeness is then mapped across the conceptual art practice and art criticism of Ian Burn. Burn attends to the differences between seeing and reading, and considers the conditions which frame how we look at images, including how w...

  8. Criticality Model

    International Nuclear Information System (INIS)

    Alsaed, A.

    2004-01-01

    The ''Disposal Criticality Analysis Methodology Topical Report'' (YMP 2003) presents the methodology for evaluating potential criticality situations in the monitored geologic repository. As stated in the referenced Topical Report, the detailed methodology for performing the disposal criticality analyses will be documented in model reports. Many of the models developed in support of the Topical Report differ from the definition of models as given in the Office of Civilian Radioactive Waste Management procedure AP-SIII.10Q, ''Models'', in that they are procedural, rather than mathematical. These model reports document the detailed methodology necessary to implement the approach presented in the Disposal Criticality Analysis Methodology Topical Report and provide calculations utilizing the methodology. Thus, the governing procedure for this type of report is AP-3.12Q, ''Design Calculations and Analyses''. The ''Criticality Model'' is of this latter type, providing a process evaluating the criticality potential of in-package and external configurations. The purpose of this analysis is to layout the process for calculating the criticality potential for various in-package and external configurations and to calculate lower-bound tolerance limit (LBTL) values and determine range of applicability (ROA) parameters. The LBTL calculations and the ROA determinations are performed using selected benchmark experiments that are applicable to various waste forms and various in-package and external configurations. The waste forms considered in this calculation are pressurized water reactor (PWR), boiling water reactor (BWR), Fast Flux Test Facility (FFTF), Training Research Isotope General Atomic (TRIGA), Enrico Fermi, Shippingport pressurized water reactor, Shippingport light water breeder reactor (LWBR), N-Reactor, Melt and Dilute, and Fort Saint Vrain Reactor spent nuclear fuel (SNF). The scope of this analysis is to document the criticality computational method. The criticality

  9. Loads and loads and loads: The influence of prospective load, retrospective load, and ongoing task load in prospective memory

    Directory of Open Access Journals (Sweden)

    Beat eMeier

    2015-06-01

    Full Text Available In prospective memory tasks different kinds of load can occur. Adding a prospective memory task can impose a load on ongoing task performance. Adding ongoing task load can affect prospective memory performance. The existence of multiple target events increases prospective load and adding complexity to the to-be-remembered action increases retrospective load. In two experiments, we systematically examined the effects of these different types of load on prospective memory performance. Results showed an effect of prospective load on costs in the ongoing task for categorical targets (Experiment 2, but not for specific targets (Experiment 1. Retrospective load and ongoing task load both affected remembering the retrospective component of the prospective memory task. We suggest that prospective load can enhance costs in the ongoing task due to additional monitoring requirements. Retrospective load and ongoing task load seem to impact the division of resources between the ongoing task and retrieval of the retrospective component, which may affect disengagement from the ongoing task. In general, the results demonstrate that the different types of load affect prospective memory differentially.

  10. Critical Review

    DEFF Research Database (Denmark)

    Rosenbaum, Ralph K.; Olsen, Stig Irving

    2018-01-01

    Manipulation and mistakes in LCA studies are as old as the tool itself, and so is its critical review. Besides preventing misuse and unsupported claims, critical review may also help identifying mistakes and more justifiable assumptions as well as generally improve the quality of a study. It thus...... supports the robustness of an LCA and increases trust in its results and conclusions. The focus of this chapter is on understanding what a critical review is, how the international standards define it, what its main elements are, and what reviewer qualifications are required. It is not the objective...... of this chapter to learn how to conduct a critical review, neither from a reviewer nor from a practitioner perspective. The foundation of this chapter and the basis for any critical review of LCA studies are the International Standards ISO 14040:2006, ISO 14044:2006 and ISO TS 14071:2014....

  11. Completion of UO{sub 2} pellets production and fuel rods load for the RA-8 critical facility; Finalizacion de la produccion de pastillas y carga de barras combustibles de UO{sub 2} para el conjunto critico RA-8

    Energy Technology Data Exchange (ETDEWEB)

    Marajofsky, Adolfo; Perez, Lidia E; Thern, Gerardo G; Altamirano, Jorge S; Benitez, Ana M; Cardenas, Hugo R; Becerra, Fabian A; Perez, Aldo E; Fuente, Mariano de la [Comision Nacional de Energia Atomica, General San Martin (Argentina). Dept. de Combustibles Nucleares

    1999-07-01

    The Advanced Fuels Division produced fuel pellets of {sup 235}U with 1.8% and 3.6% enrichment and Zry-4 cladding loads for the RA-8 reactor at Pilcaniyeu Technological Unit. For economical and availability reasons, the powder acquired was initially UO{sub 2} with 3.4% enrichment in {sup 235}U, therefore the {sup 235}U powder with 1.8% enrichment was produced by mechanical mixture. The production of fuel pellets for both enrichments was carried out by cold pressing and sintering processes in reducing atmosphere. The load of Zry-4 claddings was performed manually. The production stages can be divided into setup, qualification and production. This production allows not only to fulfill satisfactorily the new fuel rods supply for the RA-8 reactor but also to count with a new equipment and skilled personnel as well as to meet quality and assurance control methods for future pilot-scale production and even new fuel elements production. (author)

  12. Comparison of critical circumferential through-wall-crack-lengths in welds between pieces of straight pipes to welds between straigth pipes and bends with and without internal pressure at force- and displacement-controlled bending load; Vergleich kritischer Umfangsdurchrisslaengen in Schweissnaehten zwischen Geradrohrstuecken mit Schweissnaehten an Rohrbogen-Geradrohrverbindungen mit und ohne Innendruck bei kraft- und wegkontrollierter Biegebelastung

    Energy Technology Data Exchange (ETDEWEB)

    Steinbuch, R [Fachhochschule fuer Technik und Wirtschaft Reutlingen (Germany). Fachbereich Maschinenbau

    1998-11-01

    Methods for calculation of critical, circumferential through-wall crack lengths in pipes have been developed and verified by several research projects. In applications during the last few years it has been found that the force or displacement-controlled loads have to be considered separately, and this approach was integrated into the recent methods. Methods so far assumed cracks to be located in welds joining straight pipes. But this approach starts from an incomplete picture of reality, as with today`s technology, circumferential welds are less frequent in straight pipes and much more frequent in pipework of other geometry, as for instance in welds joining straight pipes and bends, or bends with longer legs, nozzles, or T-pieces. The non-linear FEM parameter study presented in the paper, covering cases with internal pressure of pipes and one-dimensional bending loads, is based on current geometries of pipework in the primary and secondary loops of industrial plants and compares the conditions induced by circumferential through-wall cracks in welds joining only straight pipes and in those joining bended and straight pipes. At the relevant, displacement-controlled bending loads due to hampered thermal expansion of the pipe system, the critical through-wall cracks lengths occurring in pipe-to-bend welds are of about the same size and importance as those in pipe-to-pipe welds. As for the case of force-controlled loads, the technical codes calculate more serious effects and require lower bending load limits. Within the range of admissible loads given in the codes, the critical through-wall crack lengths occurring in pipe-to-bend welds are similar in size to those in straight pipe welds. It is therefore a conservative or realistic approach to apply the values determined for critical through-wall crack lengths in pipe-to-pipe joints also to pipe-to-bend welds. (orig./CB) [Deutsch] Verfahren zur Berechnung kritischer Umfangdurchrisslaengen in Rohrleitungen wurden in

  13. Critical Arts

    African Journals Online (AJOL)

    both formal and informal) in culture and social theory. CRITICAL ARTS aims to challenge and ... Book Review: Brian McNair, An Introduction to Political Communication (3rd edition), London: Routledge, 2003, ISBN 0415307082, 272pp. Phil Joffe ...

  14. Critical Proximity

    Directory of Open Access Journals (Sweden)

    Jane Simon

    2010-09-01

    Full Text Available This essay considers how written language frames visual objects. Drawing on Michel Foucault’s response to Raymond Roussel’s obsessive description, the essay proposes a model of criticism where description might press up against its objects. This critical closeness is then mapped across the conceptual art practice and art criticism of Ian Burn. Burn attends to the differences between seeing and reading, and considers the conditions which frame how we look at images, including how we look at, and through words. The essay goes on to consider Meaghan Morris’s writing on Lynn Silverman’s photographs. Both Morris and Burn offer an alternative to a parasitic model of criticism and enact a patient way of looking across and through visual landscapes.

  15. Critical proximity

    Directory of Open Access Journals (Sweden)

    Simon, Jane

    2010-01-01

    Full Text Available This essay considers how written language frames visual objects. Drawing on Michel Foucault’s response to Raymond Roussel’s obsessive description, the essay proposes a model of criticism where description might press up against its objects. This critical closeness is then mapped across the conceptual art practice and art criticism of Ian Burn. Burn attends to the differences between seeing and reading, and considers the conditions which frame how we look at images, including how we look at, and through words. The essay goes on to consider Meaghan Morris’s writing on Lynn Silverman’s photographs. Both Morris and Burn offer an alternative to a parasitic model of criticism and enact a patient way of looking across and through visual landscapes.

  16. Criticality safety

    International Nuclear Information System (INIS)

    Walker, G.

    1983-01-01

    When a sufficient quantity of fissile material is brought together a self-sustaining neutron chain reaction will be started in it and will continue until some change occurs in the fissile material to stop the chain reaction. The quantity of fissile material required is the 'Critical Mass'. This is not a fixed quantity even for a given type of fissile material but varies between quite wide limits depending on a number of factors. In a nuclear reactor the critical mass of fissile material is assembled under well-defined condition to produce a controllable chain reaction. The same materials have to be handled outside the reactor in all stages of fuel element manufacture, storage, transport and irradiated fuel reprocessing. At any stage it is possible (at least in principle) to assemble a critical mass and thus initiate an accidental and uncontrollable chain reaction. Avoiding this is what criticality safety is all about. A system is just critical when the rate of production of neutrons balances the rate of loss either by escape or by absorption. The factors affecting criticality are, therefore, those which effect neutron production and loss. The principal ones are:- type of nuclide and enrichment (or isotopic composition), moderation, reflection, concentration (density), shape and interaction. Each factor is considered in detail. (author)

  17. Distribution load estimation (DLE)

    Energy Technology Data Exchange (ETDEWEB)

    Seppaelae, A; Lehtonen, M [VTT Energy, Espoo (Finland)

    1998-08-01

    The load research has produced customer class load models to convert the customers` annual energy consumption to hourly load values. The reliability of load models applied from a nation-wide sample is limited in any specific network because many local circumstances are different from utility to utility and time to time. Therefore there is a need to find improvements to the load models or, in general, improvements to the load estimates. In Distribution Load Estimation (DLE) the measurements from the network are utilized to improve the customer class load models. The results of DLE will be new load models that better correspond to the loading of the distribution network but are still close to the original load models obtained by load research. The principal data flow of DLE is presented

  18. Opposite effects of capacity load and resolution load on distractor processing.

    Science.gov (United States)

    Zhang, Weiwei; Luck, Steven J

    2015-02-01

    According to the load theory of attention, an increased perceptual load reduces distractor processing whereas an increased working memory load facilitates distractor processing. Here we raise the possibility that the critical distinction may instead be between an emphasis on resolution and an emphasis on capacity. That is, perceptual load manipulations typically emphasize resolution (fine-grained discriminations), whereas working memory load manipulations typically emphasize capacity (simultaneous processing of multiple relevant stimuli). To test the plausibility of this hypothesis, we used a visual working memory task that emphasized either the number of items to be stored (capacity load, retaining 2 vs. 4 colors) or the precision of the representations (resolution load, detecting small vs. large color changes). We found that an increased capacity load led to increased flanker interference (a measure of distractor processing), whereas an increased resolution load led to reduced flanker interference. These opposite effects of capacity load and resolution load on distractor processing mirror the previously described opposite effects of perceptual load and working memory load.

  19. Distribution load estimation - DLE

    Energy Technology Data Exchange (ETDEWEB)

    Seppaelae, A. [VTT Energy, Espoo (Finland)

    1996-12-31

    The load research project has produced statistical information in the form of load models to convert the figures of annual energy consumption to hourly load values. The reliability of load models is limited to a certain network because many local circumstances are different from utility to utility and time to time. Therefore there is a need to make improvements in the load models. Distribution load estimation (DLE) is the method developed here to improve load estimates from the load models. The method is also quite cheap to apply as it utilises information that is already available in SCADA systems

  20. Distribution load estimation - DLE

    Energy Technology Data Exchange (ETDEWEB)

    Seppaelae, A [VTT Energy, Espoo (Finland)

    1997-12-31

    The load research project has produced statistical information in the form of load models to convert the figures of annual energy consumption to hourly load values. The reliability of load models is limited to a certain network because many local circumstances are different from utility to utility and time to time. Therefore there is a need to make improvements in the load models. Distribution load estimation (DLE) is the method developed here to improve load estimates from the load models. The method is also quite cheap to apply as it utilises information that is already available in SCADA systems

  1. FFTF initial fuel loading, preanalyses, and comparison with preliminary results

    International Nuclear Information System (INIS)

    Rothrock, R.B.; Daughtry, J.W.; Zimmerman, B.D.; Petrowicz, N.E.; Bennett, R.A.; Ombrellaro, P.A.

    1980-02-01

    Disadvantages of conventional loading from the center out were circumvented by loading one trisector at a time, and connecting the control rod drivelines in each sector after it was loaded so that the rods could be operated during the loading of subsequent trisectors. This sequence was interrupted once during the loading of the final sector, to achieve initial criticality at an approximately minimum critical loading and to measure absolute subcriticality by the rod drop technique. An in-core detector was preferable to the standard FTR ex-core detectors for monitoring the initial fuel loading. Consequently, special fission chambers were installed in an instrument thimble near the core center to monitor the initial fuel loading

  2. Shot loading platform analysis

    International Nuclear Information System (INIS)

    Norman, B.F.

    1994-01-01

    This document provides the wind/seismic analysis and evaluation for the shot loading platform. Hand calculations were used for the analysis. AISC and UBC load factors were used in this evaluation. The results show that the actual loads are under the allowable loads and all requirements are met

  3. Critical Vidders

    DEFF Research Database (Denmark)

    Svegaard, Robin Sebastian Kaszmarczyk

    2015-01-01

    This article will introduce and take a look at a specific subset of the fan created remix videos known as vids, namely those that deal with feminist based critique of media. Through examples, it will show how fans construct and present their critique, and finally broach the topic of the critical ...

  4. Critical reading and critical thinking Critical reading and critical thinking

    Directory of Open Access Journals (Sweden)

    Loni Kreis Taglieber

    2008-04-01

    Full Text Available The purpose of this paper is to provide, for L1 and L2 reading and writing teachers, a brief overview of the literature about critical reading and higher level thinking skills. The teaching of these skills is still neglected in some language classes in Brazil, be it in L1 or in L2 classes. Thus, this paper may also serve as a resource guide for L1 and/or L2 reading and writing teachers who want to incorporate critical reading and thinking into their classes. In modern society, even in everyday life people frequently need to deal with complicated public and political issues, make decisions, and solve problems. In order to do this efficiently and effectively, citizens must be able to evaluate critically what they see, hear, and read. Also, with the huge amount of printed material available in all areas in this age of “information explosion” it is easy to feel overwhelmed. But often the information piled up on people’s desks and in their minds is of no use due to the enormous amount of it. The purpose of this paper is to provide, for L1 and L2 reading and writing teachers, a brief overview of the literature about critical reading and higher level thinking skills. The teaching of these skills is still neglected in some language classes in Brazil, be it in L1 or in L2 classes. Thus, this paper may also serve as a resource guide for L1 and/or L2 reading and writing teachers who want to incorporate critical reading and thinking into their classes. In modern society, even in everyday life people frequently need to deal with complicated public and political issues, make decisions, and solve problems. In order to do this efficiently and effectively, citizens must be able to evaluate critically what they see, hear, and read. Also, with the huge amount of printed material available in all areas in this age of “information explosion” it is easy to feel overwhelmed. But often the information piled up on people’s desks and in their minds is of

  5. Disruptions, loads, and dynamic response of ITER

    International Nuclear Information System (INIS)

    Nelson, B.; Riemer, B.; Sayer, R.; Strickler, D.; Barabaschi, P.; Ioki, K.; Johnson, G.; Shimizu, K.; Williamson, D.

    1995-01-01

    Plasma disruptions and the resulting electromagnetic loads are critical to the design of the vacuum vessel and in-vessel components of the International Thermonuclear Experimental Reactor (ITER). This paper describes the status of plasma disruption simulations and related analysis, including the dynamic response of the vacuum vessel and in-vessel components, stresses and deflections in the vacuum vessel, and reaction loads in the support structures

  6. Criticality accident:

    International Nuclear Information System (INIS)

    Canavese, Susana I.

    2000-01-01

    A criticality accident occurred at 10:35 on September 30, 1999. It occurred in a precipitation tank in a Conversion Test Building at the JCO Tokai Works site in Tokaimura (Tokai Village) in the Ibaraki Prefecture of Japan. STA provisionally rated this accident a 4 on the seven-level, logarithmic International Nuclear Event Scale (INES). The September 30, 1999 criticality accident at the JCO Tokai Works Site in Tokaimura, Japan in described in preliminary, technical detail. Information is based on preliminary presentations to technical groups by Japanese scientists and spokespersons, translations by technical and non-technical persons of technical web postings by various nuclear authorities, and English-language non-technical reports from various news media and nuclear-interest groups. (author)

  7. Critical dynamics

    International Nuclear Information System (INIS)

    Dekker, H.

    1980-01-01

    It is shown how to solve the master equation for a Markov process including a critical point by means of successive approximations in terms of a small parameter. A critical point occurs if, by adjusting an externally controlled quantity, the system shows a transition from normal monostable to bistable behaviour. The fundamental idea of the theory is to separate the master equation into its proper irreducible part and a corrective remainder. The irreducible or zeroth order stochastic approximation will be a relatively simple Fokker-Planck equation that contains the essential features of the process. Once the solution of this irreducible equation is known, the higher order corrections in the original master equation can be incorporated in a systematic manner. (Auth.)

  8. Critical scattering

    International Nuclear Information System (INIS)

    Stirling, W.G.; Perry, S.C.

    1996-01-01

    We outline the theoretical and experimental background to neutron scattering studies of critical phenomena at magnetic and structural phase transitions. The displacive phase transition of SrTiO 3 is discussed, along with examples from recent work on magnetic materials from the rare-earth (Ho, Dy) and actinide (NpAs, NpSb, USb) classes. The impact of synchrotron X-ray scattering is discussed in conclusion. (author) 13 figs., 18 refs

  9. Loads and loads and loads: the influence of prospective load, retrospective load, and ongoing task load in prospective memory

    Science.gov (United States)

    Meier, Beat; Zimmermann, Thomas D.

    2015-01-01

    In prospective memory tasks different kinds of load can occur. Adding a prospective memory task can impose a load on ongoing task performance. Adding ongoing task load (OTL) can affect prospective memory performance. The existence of multiple target events increases prospective load (PL) and adding complexity to the to-be-remembered action increases retrospective load (RL). In two experiments, we systematically examined the effects of these different types of load on prospective memory performance. Results showed an effect of PL on costs in the ongoing task for categorical targets (Experiment 2), but not for specific targets (Experiment 1). RL and OTL both affected remembering the retrospective component of the prospective memory task. We suggest that PL can enhance costs in the ongoing task due to additional monitoring requirements. RL and OTL seem to impact the division of resources between the ongoing task and retrieval of the retrospective component, which may affect disengagement from the ongoing task. In general, the results demonstrate that the different types of load affect prospective memory differentially. PMID:26082709

  10. Loads and loads and loads: the influence of prospective load, retrospective load, and ongoing task load in prospective memory.

    Science.gov (United States)

    Meier, Beat; Zimmermann, Thomas D

    2015-01-01

    In prospective memory tasks different kinds of load can occur. Adding a prospective memory task can impose a load on ongoing task performance. Adding ongoing task load (OTL) can affect prospective memory performance. The existence of multiple target events increases prospective load (PL) and adding complexity to the to-be-remembered action increases retrospective load (RL). In two experiments, we systematically examined the effects of these different types of load on prospective memory performance. Results showed an effect of PL on costs in the ongoing task for categorical targets (Experiment 2), but not for specific targets (Experiment 1). RL and OTL both affected remembering the retrospective component of the prospective memory task. We suggest that PL can enhance costs in the ongoing task due to additional monitoring requirements. RL and OTL seem to impact the division of resources between the ongoing task and retrieval of the retrospective component, which may affect disengagement from the ongoing task. In general, the results demonstrate that the different types of load affect prospective memory differentially.

  11. Critical Mass

    CERN Multimedia

    AUTHOR|(CDS)2070299

    2017-01-01

    Critical Mass is a cycling event typically held on the last Friday of every month; its purpose is not usually formalized beyond the direct action of meeting at a set location and time and traveling as a group through city or town streets on bikes. The event originated in 1992 in San Francisco; by the end of 2003, the event was being held in over 300 cities around the world. At CERN it is held once a year in conjunction with the national Swiss campaing "Bike to work".

  12. Wind Loads on Structures

    DEFF Research Database (Denmark)

    Dyrbye, Claes; Hansen, Svend Ole

    Wind loads have to be taken into account when designing civil engineering structures. The wind load on structures can be systematised by means of the wind load chain: wind climate (global), terrain (wind at low height), aerodynamic response (wind load to pressure), mechanical response (wind...... pressure to structural response) and design criteria. Starting with an introduction of the wind load chain, the book moves on to meteorological considerations, atmospheric boundary layer, static wind load, dynamic wind load and scaling laws used in wind-tunnel tests. The dynamic wind load covers vibrations...... induced by wind turbulence, vortex shedding, flutter and galloping. The book gives a comprehensive treatment of wind effects on structures and it will be useful for consulting engineers designing wind-sensitive structures. It will also be valuable for students of civil engineering as textbook...

  13. Carbohydrate-Loading Diet

    Science.gov (United States)

    ... Grape juice (12 ounces) 55 225 Lunch Milk, chocolate, reduced fat (12 ounces) 45 285 4 slices ... usual during carbohydrate loading to get the same benefits as a man does. Despite carbohydrate loading, you ...

  14. Autonomous Propellant Loading Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The AES Autonomous Propellant Loading (APL) project consists of three activities. The first is to develop software that will automatically control loading of...

  15. Fuel pellet loading apparatus

    International Nuclear Information System (INIS)

    1980-01-01

    Apparatus is described for loading a predetermined amount of nuclear fuel pellets into nuclear fuel elements and particularly for the automatic loading of fuel pellets from within a sealed compartment. (author)

  16. Limit loads in nozzles

    International Nuclear Information System (INIS)

    Zouain, N.

    1983-01-01

    The static method for the evaluation of the limit loads of a perfectly elasto-plastic structure is presented. Using the static theorem of Limit Analysis and the Finite Element Method, a lower bound for the colapso load can be obtained through a linear programming problem. This formulation if then applied to symmetrically loaded shells of revolution and some numerical results of limit loads in nozzles are also presented. (Author) [pt

  17. Dictionary criticism

    DEFF Research Database (Denmark)

    Nielsen, Sandro

    2018-01-01

    Dictionary criticism is part of the lexicographical universe and reviewing of electronic and printed dictionaries is not an exercise in linguistics or in subject fields but an exercise in lexicography. It does not follow from this that dictionary reviews should not be based on a linguistic approach......, but that the linguistic approach is only one of several approaches to dictionary reviewing. Similarly, the linguistic and factual competences of reviewers should not be relegated to an insignificant position in the review process. Moreover, reviewers should define the object of their reviews, the dictionary, as a complex...... information tool with several components and in terms of significant lexicographical features: lexicographical functions, data and structures. This emphasises the fact that dictionaries are much more than mere vessels of linguistic categories, namely lexicographical tools that have been developed to fulfil...

  18. Spatial electric load forecasting

    CERN Document Server

    Willis, H Lee

    2002-01-01

    Spatial Electric Load Forecasting Consumer Demand for Power and ReliabilityCoincidence and Load BehaviorLoad Curve and End-Use ModelingWeather and Electric LoadWeather Design Criteria and Forecast NormalizationSpatial Load Growth BehaviorSpatial Forecast Accuracy and Error MeasuresTrending MethodsSimulation Method: Basic ConceptsA Detailed Look at the Simulation MethodBasics of Computerized SimulationAnalytical Building Blocks for Spatial SimulationAdvanced Elements of Computerized SimulationHybrid Trending-Simulation MethodsAdvanced

  19. Cognitive Load and Cooperation

    DEFF Research Database (Denmark)

    Døssing, Felix Sebastian; Piovesan, Marco; Wengström, Erik Roland

    2017-01-01

    We study the effect of intuitive and reflective processes on cooperation using cognitive load. Compared with time constraint, which has been used in the previous literature, cognitive load is a more direct way to block reflective processes, and thus a more suitable way to study the link between...... intuition and cooperation. Using a repeated public goods game, we study the effect of different levels of cognitive load on contributions. We show that a higher cognitive load increases the initial level of cooperation. In particular, subjects are significantly less likely to fully free ride under high...... cognitive load....

  20. 14 CFR 29.865 - External loads.

    Science.gov (United States)

    2010-01-01

    ... 200 volts per meter. (iii) Be protected against any failure that could be induced by a failure mode of... operational envelope without hazard to the rotorcraft during normal flight conditions. In addition, these...-load combinations to be used for nonhuman external cargo except for the failure of critical structural...

  1. Effect of load eccentricity on the buckling of thin-walled laminated C-columns

    Science.gov (United States)

    Wysmulski, Pawel; Teter, Andrzej; Debski, Hubert

    2018-01-01

    The study investigates the behaviour of short, thin-walled laminated C-columns under eccentric compression. The tested columns are simple-supported. The effect of load inaccuracy on the critical and post-critical (local buckling) states is examined. A numerical analysis by the finite element method and experimental tests on a test stand are performed. The samples were produced from a carbon-epoxy prepreg by the autoclave technique. The experimental tests rest on the assumption that compressive loads are 1.5 higher than the theoretical critical force. Numerical modelling is performed using the commercial software package ABAQUS®. The critical load is determined by solving an eigen problem using the Subspace algorithm. The experimental critical loads are determined based on post-buckling paths. The numerical and experimental results show high agreement, thus demonstrating a significant effect of load inaccuracy on the critical load corresponding to the column's local buckling.

  2. Optimisation of load control

    International Nuclear Information System (INIS)

    Koponen, P.

    1998-01-01

    Electricity cannot be stored in large quantities. That is why the electricity supply and consumption are always almost equal in large power supply systems. If this balance were disturbed beyond stability, the system or a part of it would collapse until a new stable equilibrium is reached. The balance between supply and consumption is mainly maintained by controlling the power production, but also the electricity consumption or, in other words, the load is controlled. Controlling the load of the power supply system is important, if easily controllable power production capacity is limited. Temporary shortage of capacity causes high peaks in the energy price in the electricity market. Load control either reduces the electricity consumption during peak consumption and peak price or moves electricity consumption to some other time. The project Optimisation of Load Control is a part of the EDISON research program for distribution automation. The following areas were studied: Optimization of space heating and ventilation, when electricity price is time variable, load control model in power purchase optimization, optimization of direct load control sequences, interaction between load control optimization and power purchase optimization, literature on load control, optimization methods and field tests and response models of direct load control and the effects of the electricity market deregulation on load control. An overview of the main results is given in this chapter

  3. Optimisation of load control

    Energy Technology Data Exchange (ETDEWEB)

    Koponen, P [VTT Energy, Espoo (Finland)

    1998-08-01

    Electricity cannot be stored in large quantities. That is why the electricity supply and consumption are always almost equal in large power supply systems. If this balance were disturbed beyond stability, the system or a part of it would collapse until a new stable equilibrium is reached. The balance between supply and consumption is mainly maintained by controlling the power production, but also the electricity consumption or, in other words, the load is controlled. Controlling the load of the power supply system is important, if easily controllable power production capacity is limited. Temporary shortage of capacity causes high peaks in the energy price in the electricity market. Load control either reduces the electricity consumption during peak consumption and peak price or moves electricity consumption to some other time. The project Optimisation of Load Control is a part of the EDISON research program for distribution automation. The following areas were studied: Optimization of space heating and ventilation, when electricity price is time variable, load control model in power purchase optimization, optimization of direct load control sequences, interaction between load control optimization and power purchase optimization, literature on load control, optimization methods and field tests and response models of direct load control and the effects of the electricity market deregulation on load control. An overview of the main results is given in this chapter

  4. Indoor Air Bacterial Load and Antibiotic Susceptibility Pattern of ...

    African Journals Online (AJOL)

    % of S. aureus was identified in Critical Zone of Operating rooms. ... Reducing foot trafficking, improving the ventilation system and routine ... has to be made to maintain the aerobic bacteria load with in optimal level. ... HOW TO USE AJOL.

  5. Avalanche transmission and critical behaviour in load-bearing ...

    Indian Academy of Sciences (India)

    It is well known that many important systems such as the World Wide Web and the Internet, power grids and cellular ... in the lattice has the capacity to support unit weight if it is not connected to any site in the layer above, and has the capacity w + 1 if it is connected to sites whose capacities add up to w, in the layer above.

  6. Effects of dialogic learning on value-loaded critical thinking

    NARCIS (Netherlands)

    Frijters, S.; ten Dam, G.; Rijlaarsdam, G.

    2008-01-01

    Education should endeavour to include the competences that students need to participate in a democratic society in a responsible and adequate way. The crucial question is how this can be realized in a curriculum aimed at domain-specific knowledge and skills and organized in school subjects. In this

  7. Non-Markovian State-Dependent Networks in Critical Loading

    Science.gov (United States)

    2015-02-04

    Under suitable moment and mixing conditions which imply the invariance principle (cf. Herrndorf[8], Peligrad[17], Jacod and Shiryaev[9]), Corollary 4.1...volume 288 of Grundlehren der Mathema- tischen Wissenschaften [Fundamental Principles of Mathematical Sciences]. Springer-Verlag: Berlin, second...arrival rate control policy on throughput and work-in-process in production systems with workload dependent processing rates. Int. J. Prod. Econ . 2003, 85

  8. Physical Modelling of Cyclic Laterally Loaded Pile in Cohesionless Soil

    DEFF Research Database (Denmark)

    Hansen, Mette; Wolf, Torben K.; Rasmussen, Kristian L.

    Offshore wind turbines are normally founded with large diameter monopiles and placed in rough environments subjected to variable lateral loads from wind and waves. A long-term lateral loading may create rotation (tilt) of the pile by change in the pile-soil system which is critical in the service......Offshore wind turbines are normally founded with large diameter monopiles and placed in rough environments subjected to variable lateral loads from wind and waves. A long-term lateral loading may create rotation (tilt) of the pile by change in the pile-soil system which is critical...... in the serviceability limit state. In this paper small-scale testing of a pile subjected to cyclic, lateral loading is treated in order to investigate the effect of cyclic loading. The test setup, which is an improvement of a previous setup, is described and the first results of testing are compared with previous...

  9. Laboratory Testing of Cyclic Laterally Loaded Pile in Cohesionless Soil

    DEFF Research Database (Denmark)

    Roesen, Hanne Ravn; Ibsen, Lars Bo; Hansen, Mette

    2013-01-01

    Offshore wind turbines are normally founded with large diameter monopiles and placed in rough environments subjected to variable lateral loads from wind and waves. A long-term lateral loading may create rotation (tilt) of the pile by change in the pile-soil system which is critical in the service......Offshore wind turbines are normally founded with large diameter monopiles and placed in rough environments subjected to variable lateral loads from wind and waves. A long-term lateral loading may create rotation (tilt) of the pile by change in the pile-soil system which is critical...... in the serviceability limit state. In this paper small-scale testing of a pile subjected to cyclic, lateral loading is treated in order to investigate the effect of cyclic loading. The test setup, which is an improvement of a previous setup, is described and the first results of testing are compared with previous...

  10. Distracted and confused?: selective attention under load.

    Science.gov (United States)

    Lavie, Nilli

    2005-02-01

    The ability to remain focused on goal-relevant stimuli in the presence of potentially interfering distractors is crucial for any coherent cognitive function. However, simply instructing people to ignore goal-irrelevant stimuli is not sufficient for preventing their processing. Recent research reveals that distractor processing depends critically on the level and type of load involved in the processing of goal-relevant information. Whereas high perceptual load can eliminate distractor processing, high load on "frontal" cognitive control processes increases distractor processing. These findings provide a resolution to the long-standing early and late selection debate within a load theory of attention that accommodates behavioural and neuroimaging data within a framework that integrates attention research with executive function.

  11. Impact of measurement uncertainty from experimental load distribution factors on bridge load rating

    Science.gov (United States)

    Gangone, Michael V.; Whelan, Matthew J.

    2018-03-01

    Load rating and testing of highway bridges is important in determining the capacity of the structure. Experimental load rating utilizes strain transducers placed at critical locations of the superstructure to measure normal strains. These strains are then used in computing diagnostic performance measures (neutral axis of bending, load distribution factor) and ultimately a load rating. However, it has been shown that experimentally obtained strain measurements contain uncertainties associated with the accuracy and precision of the sensor and sensing system. These uncertainties propagate through to the diagnostic indicators that in turn transmit into the load rating calculation. This paper will analyze the effect that measurement uncertainties have on the experimental load rating results of a 3 span multi-girder/stringer steel and concrete bridge. The focus of this paper will be limited to the uncertainty associated with the experimental distribution factor estimate. For the testing discussed, strain readings were gathered at the midspan of each span of both exterior girders and the center girder. Test vehicles of known weight were positioned at specified locations on each span to generate maximum strain response for each of the five girders. The strain uncertainties were used in conjunction with a propagation formula developed by the authors to determine the standard uncertainty in the distribution factor estimates. This distribution factor uncertainty is then introduced into the load rating computation to determine the possible range of the load rating. The results show the importance of understanding measurement uncertainty in experimental load testing.

  12. Perceptual load in different regions of the visual scene and its relevance for driving.

    Science.gov (United States)

    Marciano, Hadas; Yeshurun, Yaffa

    2015-06-01

    The aim of this study was to better understand the role played by perceptual load, at both central and peripheral regions of the visual scene, in driving safety. Attention is a crucial factor in driving safety, and previous laboratory studies suggest that perceptual load is an important factor determining the efficiency of attentional selectivity. Yet, the effects of perceptual load on driving were never studied systematically. Using a driving simulator, we orthogonally manipulated the load levels at the road (central load) and its sides (peripheral load), while occasionally introducing critical events at one of these regions. Perceptual load affected driving performance at both regions of the visual scene. Critically, the effect was different for central versus peripheral load: Whereas load levels on the road mainly affected driving speed, load levels on its sides mainly affected the ability to detect critical events initiating from the roadsides. Moreover, higher levels of peripheral load impaired performance but mainly with low levels of central load, replicating findings with simple letter stimuli. Perceptual load has a considerable effect on driving, but the nature of this effect depends on the region of the visual scene at which the load is introduced. Given the observed importance of perceptual load, authors of future studies of driving safety should take it into account. Specifically, these findings suggest that our understanding of factors that may be relevant for driving safety would benefit from studying these factors under different levels of load at different regions of the visual scene. © 2014, Human Factors and Ergonomics Society.

  13. Visual perceptual load induces inattentional deafness.

    Science.gov (United States)

    Macdonald, James S P; Lavie, Nilli

    2011-08-01

    In this article, we establish a new phenomenon of "inattentional deafness" and highlight the level of load on visual attention as a critical determinant of this phenomenon. In three experiments, we modified an inattentional blindness paradigm to assess inattentional deafness. Participants made either a low- or high-load visual discrimination concerning a cross shape (respectively, a discrimination of line color or of line length with a subtle length difference). A brief pure tone was presented simultaneously with the visual task display on a final trial. Failures to notice the presence of this tone (i.e., inattentional deafness) reached a rate of 79% in the high-visual-load condition, significantly more than in the low-load condition. These findings establish the phenomenon of inattentional deafness under visual load, thereby extending the load theory of attention (e.g., Lavie, Journal of Experimental Psychology. Human Perception and Performance, 25, 596-616, 1995) to address the cross-modal effects of visual perceptual load.

  14. Concentrated loads on concrete

    DEFF Research Database (Denmark)

    Lorenzen, Karen Grøndahl; Nielsen, Mogens Peter

    1997-01-01

    This report deals with concentrated loads on concrete.A new upper bound solution in the axisymmetrical case of a point load in the center of the end face of a cylinder is developed.Based on previous work dealing with failure mechanisms and upper bound solutions, new approximate formulas are devel......This report deals with concentrated loads on concrete.A new upper bound solution in the axisymmetrical case of a point load in the center of the end face of a cylinder is developed.Based on previous work dealing with failure mechanisms and upper bound solutions, new approximate formulas...

  15. Load regulating expansion fixture

    International Nuclear Information System (INIS)

    Wagner, L.M.; Strum, M.J.

    1998-01-01

    A free standing self contained device for bonding ultra thin metallic films, such as 0.001 inch beryllium foils is disclosed. The device will regulate to a predetermined load for solid state bonding when heated to a bonding temperature. The device includes a load regulating feature, whereby the expansion stresses generated for bonding are regulated and self adjusting. The load regulator comprises a pair of friction isolators with a plurality of annealed copper members located there between. The device, with the load regulator, will adjust to and maintain a stress level needed to successfully and economically complete a leak tight bond without damaging thin foils or other delicate components. 1 fig

  16. Laterally loaded masonry

    DEFF Research Database (Denmark)

    Raun Gottfredsen, F.

    In this thesis results from experiments on mortar joints and masonry as well as methods of calculation of strength and deformation of laterally loaded masonry are presented. The strength and deformation capacity of mortar joints have been determined from experiments involving a constant compressive...... stress and increasing shear. The results show a transition to pure friction as the cohesion is gradually destroyed. An interface model of a mortar joint that can take into account this aspect has been developed. Laterally loaded masonry panels have also been tested and it is found to be characteristic...... that laterally loaded masonry exhibits a non-linear load-displacement behaviour with some ductility....

  17. Application of Model Based Prognostics to Pneumatic Valves in a Cryogenic Propellant Loading Testbed

    Data.gov (United States)

    National Aeronautics and Space Administration — Pneumatic-actuated valves are critical components in many applications, including cryogenic propellant loading for space operations. For these components, failures...

  18. Impact of sampling strategy on stream load estimates in till landscape of the Midwest

    Science.gov (United States)

    Vidon, P.; Hubbard, L.E.; Soyeux, E.

    2009-01-01

    Accurately estimating various solute loads in streams during storms is critical to accurately determine maximum daily loads for regulatory purposes. This study investigates the impact of sampling strategy on solute load estimates in streams in the US Midwest. Three different solute types (nitrate, magnesium, and dissolved organic carbon (DOC)) and three sampling strategies are assessed. Regardless of the method, the average error on nitrate loads is higher than for magnesium or DOC loads, and all three methods generally underestimate DOC loads and overestimate magnesium loads. Increasing sampling frequency only slightly improves the accuracy of solute load estimates but generally improves the precision of load calculations. This type of investigation is critical for water management and environmental assessment so error on solute load calculations can be taken into account by landscape managers, and sampling strategies optimized as a function of monitoring objectives. ?? 2008 Springer Science+Business Media B.V.

  19. Gearbox Reliability Collaborative Investigation of Gearbox Motion and High-Speed-Shaft Loads

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Jon [National Renewable Energy Lab. (NREL), Golden, CO (United States); Guo, Yi [National Renewable Energy Lab. (NREL), Golden, CO (United States); Sethuraman, Latha [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-03-18

    This paper extends a model-to-test validation effort to examine the effect of different constant rotor torque and moment conditions and intentional generator misalignment on the gearbox motion and high-speed-shaft loads. Fully validating gearbox motion and high-speed-shaft loads across a range of test conditions is a critical precursor to examining the bearing loads, as the gearbox motion and high-speed-shaft loads are the drivers of these bearing loads.

  20. Load Balancing in Hypergraphs

    Science.gov (United States)

    Delgosha, Payam; Anantharam, Venkat

    2018-03-01

    Consider a simple locally finite hypergraph on a countable vertex set, where each edge represents one unit of load which should be distributed among the vertices defining the edge. An allocation of load is called balanced if load cannot be moved from a vertex to another that is carrying less load. We analyze the properties of balanced allocations of load. We extend the concept of balancedness from finite hypergraphs to their local weak limits in the sense of Benjamini and Schramm (Electron J Probab 6(23):13, 2001) and Aldous and Steele (in: Probability on discrete structures. Springer, Berlin, pp 1-72, 2004). To do this, we define a notion of unimodularity for hypergraphs which could be considered an extension of unimodularity in graphs. We give a variational formula for the balanced load distribution and, in particular, we characterize it in the special case of unimodular hypergraph Galton-Watson processes. Moreover, we prove the convergence of the maximum load under some conditions. Our work is an extension to hypergraphs of Anantharam and Salez (Ann Appl Probab 26(1):305-327, 2016), which considered load balancing in graphs, and is aimed at more comprehensively resolving conjectures of Hajek (IEEE Trans Inf Theory 36(6):1398-1414, 1990).

  1. Structural load combinations

    International Nuclear Information System (INIS)

    Hwang, H.; Reich, M.; Ellingwood, B.; Shinozuka, M.

    1985-01-01

    This paper presents the latest results of the program entitled, ''Probability Based Load Combinations For Design of Category I Structures''. In FY 85, a probability-based reliability analysis method has been developed to evaluate safety of shear wall structures. The shear walls are analyzed using stick models with beam elements and may be subjected to dead load, live load and in-plane eqrthquake. Both shear and flexure limit states are defined analytically. The limit state probabilities can be evaluated on the basis of these limit states. Utilizing the reliability analysis method mentioned above, load combinations for the design of shear wall structures have been established. The proposed design criteria are in the load and resistance factor design (LRFD) format. In this study, the resistance factors for shear and flexure and load factors for dead and live loads are preassigned, while the load factor for SSE is determined for a specified target limit state probability of 1.0 x 10 -6 or 1.0 x 10 -5 during a lifetime of 40 years. 23 refs., 9 tabs

  2. Load Induced Blindness

    Science.gov (United States)

    Macdonald, James S. P.; Lavie, Nilli

    2008-01-01

    Although the perceptual load theory of attention has stimulated a great deal of research, evidence for the role of perceptual load in determining perception has typically relied on indirect measures that infer perception from distractor effects on reaction times or neural activity (see N. Lavie, 2005, for a review). Here we varied the level of…

  3. Structural load combinations

    International Nuclear Information System (INIS)

    Hwang, H.; Reich, M.; Ellingwood, B.; Shinozuka, M.

    1986-01-01

    This paper presents the latest results of the program entitled, ''Probability Based Load Combinations For Design of Category I Structures''. In FY 85, a probability-based reliability analysis method has been developed to evaluate safety of shear wall structures. The shear walls are analyzed using stick models with beam elements and may be subjected to dead load, live load and in-plane earthquake. Both shear and flexure limit states are defined analytically. The limit state probabilities can be evaluated on the basis of these limit states. Utilizing the reliability analysis method mentioned above, load combinations for the design of shear wall structures have been established. The proposed design criteria are in the load and resistance factor design (LRFD) format. In this study, the resistance factors for shear and flexure and load factors for dead and live loads are preassigned, while the load factor for SSE is determined for a specified target limit state probability of 1.0 x 10 -6 or 1.0 x 10 -5 during a lifetime of 40 years

  4. Load event: Aircraft crash

    International Nuclear Information System (INIS)

    Fritsch, H.

    1985-01-01

    The bibliography includes 48 quotations, up to the year 1983, on the following issues: Experiments and computational methods. Design load for the dimensioning of reinforced concrete buildings and components with respect to the dynamic load in the event of an aircraft crash. (orig./HP) [de

  5. Rating curve estimation of nutrient loads in Iowa rivers

    Science.gov (United States)

    Stenback, G.A.; Crumpton, W.G.; Schilling, K.E.; Helmers, M.J.

    2011-01-01

    Accurate estimation of nutrient loads in rivers and streams is critical for many applications including determination of sources of nutrient loads in watersheds, evaluating long-term trends in loads, and estimating loading to downstream waterbodies. Since in many cases nutrient concentrations are measured on a weekly or monthly frequency, there is a need to estimate concentration and loads during periods when no data is available. The objectives of this study were to: (i) document the performance of a multiple regression model to predict loads of nitrate and total phosphorus (TP) in Iowa rivers and streams; (ii) determine whether there is any systematic bias in the load prediction estimates for nitrate and TP; and (iii) evaluate streamflow and concentration factors that could affect the load prediction efficiency. A commonly cited rating curve regression is utilized to estimate riverine nitrate and TP loads for rivers in Iowa with watershed areas ranging from 17.4 to over 34,600km2. Forty-nine nitrate and 44 TP datasets each comprising 5-22years of approximately weekly to monthly concentrations were examined. Three nitrate data sets had sample collection frequencies averaging about three samples per week. The accuracy and precision of annual and long term riverine load prediction was assessed by direct comparison of rating curve load predictions with observed daily loads. Significant positive bias of annual and long term nitrate loads was detected. Long term rating curve nitrate load predictions exceeded observed loads by 25% or more at 33% of the 49 measurement sites. No bias was found for TP load prediction although 15% of the 44 cases either underestimated or overestimate observed long-term loads by more than 25%. The rating curve was found to poorly characterize nitrate and phosphorus variation in some rivers. ?? 2010 .

  6. A real time multi-server multi-client coherent database for a new high voltage system

    International Nuclear Information System (INIS)

    Gorbics, M.; Green, M.

    1995-01-01

    A high voltage system has been designed to allow multiple users (clients) access to the database of measured values and settings. This database is actively maintained in real time for a given mainframe containing multiple modules each having their own database. With limited CPU nd memory resources the mainframe system provides a data coherency scheme for multiple clients which (1) allows the client to determine when and what values need to be updated, (2) allows for changes from one client to be detected by another client, and (3) does not depend on the mainframe system tracking client accesses

  7. Load Balancing Scientific Applications

    Energy Technology Data Exchange (ETDEWEB)

    Pearce, Olga Tkachyshyn [Texas A & M Univ., College Station, TX (United States)

    2014-12-01

    The largest supercomputers have millions of independent processors, and concurrency levels are rapidly increasing. For ideal efficiency, developers of the simulations that run on these machines must ensure that computational work is evenly balanced among processors. Assigning work evenly is challenging because many large modern parallel codes simulate behavior of physical systems that evolve over time, and their workloads change over time. Furthermore, the cost of imbalanced load increases with scale because most large-scale scientific simulations today use a Single Program Multiple Data (SPMD) parallel programming model, and an increasing number of processors will wait for the slowest one at the synchronization points. To address load imbalance, many large-scale parallel applications use dynamic load balance algorithms to redistribute work evenly. The research objective of this dissertation is to develop methods to decide when and how to load balance the application, and to balance it effectively and affordably. We measure and evaluate the computational load of the application, and develop strategies to decide when and how to correct the imbalance. Depending on the simulation, a fast, local load balance algorithm may be suitable, or a more sophisticated and expensive algorithm may be required. We developed a model for comparison of load balance algorithms for a specific state of the simulation that enables the selection of a balancing algorithm that will minimize overall runtime.

  8. Status of load management

    Energy Technology Data Exchange (ETDEWEB)

    Juchymenko, A

    1983-08-01

    A summary is presented of the status of load management, defined as any activity by an electric utility to affect the size and characteristics of its load. Load management is currently viewed by electric utilities as an important tool for marketing electricity in a competitive fuel situation. A major aim of the National Energy Program is to reduce Canada's dependence on oil by 1990 to 10% of the energy used by all markets. As a result, electricity may play a greater role in the supply of primary energy. Research in load management has been directed mostly towards the residential market, especially direct control of domestic hot water heaters and air conditioners. Studies conducted in Canada and the U.S. to determine user's receptiveness to direct control of loads and thermal energy storage systems indicate that these load management techniques are in most cases not acceptable to customers, who prefer voluntary reduction in demand. The potential exists in the industrial market to use load management to assist in electrifying many of the fossil fuel-fired processes at competitive energy prices. Some of the more important applications include an industrial heat pump to heat liquids to 120{degree}C, induction heating for melting and heat treating of metals, and mechanical vapor recompression equipment to produce proces steam. 21 refs., 2 figs., 2 tabs.

  9. A Novel Load Capacity Model with a Tunable Proportion of Load Redistribution against Cascading Failures

    Directory of Open Access Journals (Sweden)

    Zhen-Hao Zhang

    2018-01-01

    Full Text Available Defence against cascading failures is of great theoretical and practical significance. A novel load capacity model with a tunable proportion is proposed. We take degree and clustering coefficient into account to redistribute the loads of broken nodes. The redistribution is local, where the loads of broken nodes are allocated to their nearest neighbours. Our model has been applied on artificial networks as well as two real networks. Simulation results show that networks get more vulnerable and sensitive to intentional attacks along with the decrease of average degree. In addition, the critical threshold from collapse to intact states is affected by the tunable parameter. We can adjust the tunable parameter to get the optimal critical threshold and make the systems more robust against cascading failures.

  10. Conceptual and methodological concerns in the theory of perceptual load.

    Science.gov (United States)

    Benoni, Hanna; Tsal, Yehoshua

    2013-01-01

    The present paper provides a short critical review of the theory of perceptual load. It closely examines the basic tenets and assumptions of the theory and identifies major conceptual and methodological problems that have been largely ignored in the literature. The discussion focuses on problems in the definition of the concept of perceptual load, on the circularity in the characterization and manipulation of perceptual load and the confusion between the concept of perceptual load and its operationalization. The paper also selectively reviews evidence supporting the theory as well as inconsistent evidence which proposed alternative dominant factors influencing the efficacy of attentional selection.

  11. Load Balancing of Parallel Monte Carlo Transport Calculations

    International Nuclear Information System (INIS)

    Procassini, R J; O'Brien, M J; Taylor, J M

    2005-01-01

    The performance of parallel Monte Carlo transport calculations which use both spatial and particle parallelism is increased by dynamically assigning processors to the most worked domains. Since he particle work load varies over the course of the simulation, this algorithm determines each cycle if dynamic load balancing would speed up the calculation. If load balancing is required, a small number of particle communications are initiated in order to achieve load balance. This method has decreased the parallel run time by more than a factor of three for certain criticality calculations

  12. Dynamic Load Balancing of Parallel Monte Carlo Transport Calculations

    International Nuclear Information System (INIS)

    O'Brien, M; Taylor, J; Procassini, R

    2004-01-01

    The performance of parallel Monte Carlo transport calculations which use both spatial and particle parallelism is increased by dynamically assigning processors to the most worked domains. Since the particle work load varies over the course of the simulation, this algorithm determines each cycle if dynamic load balancing would speed up the calculation. If load balancing is required, a small number of particle communications are initiated in order to achieve load balance. This method has decreased the parallel run time by more than a factor of three for certain criticality calculations

  13. Conceptual and Methodological Concerns in the Theory of Perceptual Load

    Directory of Open Access Journals (Sweden)

    Hanna eBenoni

    2013-08-01

    Full Text Available The present paper provides a short critical review of the theory of perceptual load. It closely examines the basic tenets and assumptions of the theory and identifies major conceptual and methodological problems that have been largely ignored in the literature. The discussion focuses on problems in the definition of the concept of perceptual load, on the circularity in the characterization and manipulation of perceptual load and the confusion between the concept of perceptual load and its operationalization. The paper also selectively reviews evidence supporting the theory as well as inconsistent evidence which proposed alternative dominant factors influencing the efficacy of attentional selection.

  14. Filament instability under constant loads

    Science.gov (United States)

    Monastra, A. G.; Carusela, M. F.; D’Angelo, M. V.; Bruno, L.

    2018-04-01

    Buckling of semi-flexible filaments appears in different systems and scales. Some examples are: fibers in geophysical applications, microtubules in the cytoplasm of eukaryotic cells and deformation of polymers freely suspended in a flow. In these examples, instabilities arise when a system’s parameter exceeds a critical value, being the Euler force the most known. However, the complete time evolution and wavelength of buckling processes are not fully understood. In this work we solve analytically the time evolution of a filament under a constant compressive force in the small amplitude approximation. This gives an insight into the variable force scenario in terms of normal modes. The evolution is highly sensitive to the initial configuration and to the magnitude of the compressive load. This model can be a suitable approach to many different real situations.

  15. Lumbriculus variegatus loading study

    Data.gov (United States)

    U.S. Environmental Protection Agency — Results from sediment bioaccumulation tests with Lumbriculus variegatus with evaluating the effects of organism loading density. This dataset is associated with the...

  16. LOADING SIMULATION PROGRAM C

    Science.gov (United States)

    LSPC is the Loading Simulation Program in C++, a watershed modeling system that includes streamlined Hydrologic Simulation Program Fortran (HSPF) algorithms for simulating hydrology, sediment, and general water quality

  17. LOADING SIMULATION PROGRAM C

    Data.gov (United States)

    U.S. Environmental Protection Agency — LSPC is the Loading Simulation Program in C++, a watershed modeling system that includes streamlined Hydrologic Simulation Program Fortran (HSPF) algorithms for...

  18. Cognitive load theory

    NARCIS (Netherlands)

    Kirschner, Paul A.; Kirschner, Femke; Paas, Fred

    2010-01-01

    Kirschner, P. A., Kirschner, F. C., & Paas, F. (2009). Cognitive load theory. In E. M. Anderman & L. H. Anderman (Eds.). Psychology of classroom learning: An encyclopedia, Volume 1, a-j (pp. 205-209). Detroit, MI: Macmillan Reference.

  19. Static Loads Test Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Provides the capability to perform large-scale structural loads testing on spacecraft and other structures. Results from these tests can be used to verify...

  20. Load proportional safety brake

    Science.gov (United States)

    Cacciola, M. J.

    1979-01-01

    This brake is a self-energizing mechanical friction brake and is intended for use in a rotary drive system. It incorporates a torque sensor which cuts power to the power unit on any overload condition. The brake is capable of driving against an opposing load or driving, paying-out, an aiding load in either direction of rotation. The brake also acts as a no-back device when torque is applied to the output shaft. The advantages of using this type of device are: (1) low frictional drag when driving; (2) smooth paying-out of an aiding load with no runaway danger; (3) energy absorption proportional to load; (4) no-back activates within a few degrees of output shaft rotation and resets automatically; and (5) built-in overload protection.

  1. Plug Load Data

    Data.gov (United States)

    National Aeronautics and Space Administration — We provide MATLAB binary files (.mat) and comma separated values files of data collected from a pilot study of a plug load management system that allows for the...

  2. Change in Soil Porosity under Load

    Science.gov (United States)

    Dyba, V. P.; Skibin, E. G.

    2017-11-01

    The theoretical basis for the process of soil compaction under various loading paths is considered in the article, the theoretical assumptions are compared with the results of the tests of clay soil on a stabilometer. The variant of the critical state model of the sealing plastic-rigid environment is also considered the strength characteristics of which depend on the porosity coefficient. The loading surface is determined by the results of compression and stabilometrical tests. In order to clarify the results of this task, it is necessary to carry out stabilometric tests under conditions of simple loading, i.e. where the vertical pressure would be proportional to the compression pressure σ3 = kσ1. Within the study the attempts were made to confirm the model given in the beginning of the article by laboratory tests. After the analysis of the results, the provided theoretical assumptions were confirmed.

  3. Quasi-static structural optimization under the seismic loads

    International Nuclear Information System (INIS)

    Choi, W. S.; Lee, K. M.; Kim, T. W.

    2001-01-01

    For preliminaries to optimization of SMART under the seismic loads, a quasi-static structural optimization for elastic structures under dynamic loads is presented. An equivalent static load (ESL) set is defined as a static load set, which generates the same displacement field as that from a dynamic load at a certain time. Multiple ESL sets calculated at all the time intervals are employed to represent the various states of the structure under the dynamic load. They can cover all the critical states that might happen at arbitrary times. The continuous characteristics of a dynamic load are considered by multiple static load sets. The calculated sets of ESLs are utilized as a multiple loading condition in the optimization process. A design cycle is defined as a circulated process between an analysis domain and a design domain. The analysis domain gives the loading condition needed in the design domain. The design domain gives a new updated design to be verified by the analysis domain in the next design cycle. The design cycles are iterated until the design converges. Structural optimization with dynamic loads is tangible by the proposed method. Standard example problems are solved to verify the validity of the method

  4. Critical fatigue behaviour in brittle glasses

    Indian Academy of Sciences (India)

    Unknown

    Abstract. The dynamic fatigue fracture behaviour in different glasses under various sub-threshold loading conditions are analysed here employing an anomalous diffusion model. Critical dynamical behaviour in the time-to-fracture and the growth of the micro-crack sizes, similar to that observed in such materials in the case.

  5. Load power device, system and method of load control and management employing load identification

    Science.gov (United States)

    Yang, Yi; Luebke, Charles John; Schoepf, Thomas J.

    2018-01-09

    A load power device includes a power input, at least one power output for at least one load, a plurality of sensors structured to sense voltage and current at the at least one power output, and a processor. The processor provides: (a) load identification based upon the sensed voltage and current, and (b) load control and management based upon the load identification.

  6. Critical component wear in heavy duty engines

    CERN Document Server

    Lakshminarayanan, P A

    2011-01-01

    The critical parts of a heavy duty engine are theoretically designed for infinite life without mechanical fatigue failure. Yet the life of an engine is in reality determined by wear of the critical parts. Even if an engine is designed and built to have normal wear life, abnormal wear takes place either due to special working conditions or increased loading.  Understanding abnormal and normal wear enables the engineer to control the external conditions leading to premature wear, or to design the critical parts that have longer wear life and hence lower costs. The literature on wear phenomenon r

  7. Critical State of Sand Matrix Soils

    Science.gov (United States)

    Marto, Aminaton; Tan, Choy Soon; Makhtar, Ahmad Mahir; Kung Leong, Tiong

    2014-01-01

    The Critical State Soil Mechanic (CSSM) is a globally recognised framework while the critical states for sand and clay are both well established. Nevertheless, the development of the critical state of sand matrix soils is lacking. This paper discusses the development of critical state lines and corresponding critical state parameters for the investigated material, sand matrix soils using sand-kaolin mixtures. The output of this paper can be used as an interpretation framework for the research on liquefaction susceptibility of sand matrix soils in the future. The strain controlled triaxial test apparatus was used to provide the monotonic loading onto the reconstituted soil specimens. All tested soils were subjected to isotropic consolidation and sheared under undrained condition until critical state was ascertain. Based on the results of 32 test specimens, the critical state lines for eight different sand matrix soils were developed together with the corresponding values of critical state parameters, M, λ, and Γ. The range of the value of M, λ, and Γ is 0.803–0.998, 0.144–0.248, and 1.727–2.279, respectively. These values are comparable to the critical state parameters of river sand and kaolin clay. However, the relationship between fines percentages and these critical state parameters is too scattered to be correlated. PMID:24757417

  8. PRECLOSURE CRITICALITY ANALYSIS PROCESS REPORT

    International Nuclear Information System (INIS)

    Danise, A.E.

    2004-01-01

    This report describes a process for performing preclosure criticality analyses for a repository at Yucca Mountain, Nevada. These analyses will be performed from the time of receipt of fissile material until permanent closure of the repository (preclosure period). The process describes how criticality safety analyses will be performed for various configurations of waste in or out of waste packages that could occur during preclosure as a result of normal operations or event sequences. The criticality safety analysis considers those event sequences resulting in unanticipated moderation, loss of neutron absorber, geometric changes, or administrative errors in waste form placement (loading) of the waste package. The report proposes a criticality analyses process for preclosure to allow a consistent transition from preclosure to postclosure, thereby possibly reducing potential cost increases and delays in licensing of Yucca Mountain. The proposed approach provides the advantage of using a parallel regulatory framework for evaluation of preclosure and postclosure performance and is consistent with the U.S. Nuclear Regulatory Commission's approach of supporting risk-informed, performance-based regulation for fuel cycle facilities, ''Yucca Mountain Review Plan, Final Report'', and 10 CFR Part 63. The criticality-related criteria for ensuring subcriticality are also described as well as which guidance documents will be utilized. Preclosure operations and facilities have significant similarities to existing facilities and operations currently regulated by the U.S. Nuclear Regulatory Commission; therefore, the design approach for preclosure criticality safety will be dictated by existing regulatory requirements while using a risk-informed approach with burnup credit for in-package operations

  9. Nuclear criticality safety guide

    International Nuclear Information System (INIS)

    Pruvost, N.L.; Paxton, H.C.

    1996-09-01

    This technical reference document cites information related to nuclear criticality safety principles, experience, and practice. The document also provides general guidance for criticality safety personnel and regulators

  10. Nuclear criticality safety guide

    Energy Technology Data Exchange (ETDEWEB)

    Pruvost, N.L.; Paxton, H.C. [eds.

    1996-09-01

    This technical reference document cites information related to nuclear criticality safety principles, experience, and practice. The document also provides general guidance for criticality safety personnel and regulators.

  11. Ocean Tide Loading Computation

    Science.gov (United States)

    Agnew, Duncan Carr

    2005-01-01

    September 15,2003 through May 15,2005 This grant funds the maintenance, updating, and distribution of programs for computing ocean tide loading, to enable the corrections for such loading to be more widely applied in space- geodetic and gravity measurements. These programs, developed under funding from the CDP and DOSE programs, incorporate the most recent global tidal models developed from Topex/Poscidon data, and also local tide models for regions around North America; the design of the algorithm and software makes it straightforward to combine local and global models.

  12. DYNAMIC LOAD DAMPER MODELING

    Directory of Open Access Journals (Sweden)

    Loktev Aleksey Alekseevich

    2013-01-01

    Full Text Available The authors present their findings associated with their modeling of a dynamic load damper. According to the authors, the damper is to be installed onto a structure or its element that may be exposed to impact, vibration or any other dynamic loading. The damper is composed of paralleled or consecutively connected viscous and elastic elements. The authors study the influence of viscosity and elasticity parameters of the damper produced onto the regular displacement of points of the structure to be protected and onto the regular acceleration transmitted immediately from the damper to the elements positioned below it.

  13. Lateral loadings on snubber assemblies

    International Nuclear Information System (INIS)

    Raphael, L.S.

    1981-01-01

    This paper examines the installation of snubber assemblies in power plants with respect to transverse or lateral loads as well as axial loads. Evaluation of the effects of low level, lateral loads was performed by analytical means. At higher loadings, the snubber assembly could no longer be treated as a column; therefore, the effects of lateral loadings was determined by test. The test consisted of applying both lateral and axial loads simultaneously. Results of both the analysis and the test showed that the application of lateral loads had a considerable effect on the snubber assemblies

  14. Fuel Load (FL)

    Science.gov (United States)

    Duncan C. Lutes; Robert E. Keane

    2006-01-01

    The Fuel Load method (FL) is used to sample dead and down woody debris, determine depth of the duff/ litter profile, estimate the proportion of litter in the profile, and estimate total vegetative cover and dead vegetative cover. Down woody debris (DWD) is sampled using the planar intercept technique based on the methodology developed by Brown (1974). Pieces of dead...

  15. HIV Viral Load

    Science.gov (United States)

    ... PF4 Antibody Hepatitis A Testing Hepatitis B Testing Hepatitis C Testing HER2/neu Herpes Testing High-sensitivity C-reactive Protein (hs-CRP) Histamine Histone Antibody HIV Antibody and HIV Antigen (p24) HIV Antiretroviral Drug Resistance Testing, Genotypic HIV Viral Load HLA Testing HLA- ...

  16. Loading device for incinerator

    International Nuclear Information System (INIS)

    Hempelmann, W.

    1983-01-01

    An incinerator for radioactive waste is described. Heat radiation from the incinerator into the loading device is reduced by the design of the slider with a ceramic plate and the conical widening of the pot, and also by fixing a metal plate between the pot and the floor. (PW) [de

  17. Side loading filter apparatus

    International Nuclear Information System (INIS)

    Reynolds, K.E.

    1981-01-01

    A side loading filter chamber for use with radioactive gases is described. The equipment incorporates an inexpensive, manually operated, mechanism for aligning filter units with a number of laterally spaced wall openings and for removing the units from the chamber. (U.K.)

  18. EQUATING FACULTY LOADS.

    Science.gov (United States)

    OOSTING, KENNETH W.

    AT ALPENA COMMUNITY COLLEGE, A NORMAL TEACHING LOAD FOR ANY FACULTY MEMBER IS 14-16 SEMESTER HOURS, WITH 75-125 STUDENTS AND 2-3 PREPARATIONS. VARIATIONS FROM THE SCHEDULE ARE IN ACCORDANCE WITH SPECIFIC FORMULAS RELATING TO TOTAL MEMBERS OF STUDENTS, NUMBERS OF PREPARATIONS, ASSIGNMENT TO ENGLISH COMPOSITION CLASSES, NEW COURSES, AND CLASSES…

  19. Probabilistic Load Flow

    DEFF Research Database (Denmark)

    Chen, Peiyuan; Chen, Zhe; Bak-Jensen, Birgitte

    2008-01-01

    This paper reviews the development of the probabilistic load flow (PLF) techniques. Applications of the PLF techniques in different areas of power system steady-state analysis are also discussed. The purpose of the review is to identify different available PLF techniques and their corresponding...

  20. Duration of load revisited

    DEFF Research Database (Denmark)

    Hoffmeyer, Preben; Sørensen, John Dalsgaard

    2007-01-01

    A duration of load study representing 13 years of testing was recently terminated. Preliminary results have been published over the years. This paper represents the final account of the study, which was focused on the influ-ence of moisture content on time to failure for structural timber subject...

  1. Robust surgery loading

    NARCIS (Netherlands)

    Hans, Elias W.; Wullink, Gerhard; van Houdenhoven, Mark; Kazemier, Geert

    2008-01-01

    We consider the robust surgery loading problem for a hospital’s operating theatre department, which concerns assigning surgeries and sufficient planned slack to operating room days. The objective is to maximize capacity utilization and minimize the risk of overtime, and thus cancelled patients. This

  2. Temoporfin-loaded liposomes

    DEFF Research Database (Denmark)

    Kuntsche, Judith; Freisleben, Ines; Steiniger, Frank

    2010-01-01

    . In contrast, if phospholipids with longer fatty acid chains (distearoylphosphatidylcholine/-glycerol) were used, phase transitions were well above body temperature even at high drug load. Size and thermal behavior were not distinctly influenced by the addition of pegylated lipids but cryo-electron microscopic...

  3. Distribution load forecast with interactive correction of horizon loads

    International Nuclear Information System (INIS)

    Glamochanin, V.; Andonov, D.; Gagovski, I.

    1994-01-01

    This paper presents the interactive distribution load forecast application that performs the distribution load forecast with interactive correction of horizon loads. It consists of two major parts implemented in Fortran and Visual Basic. The Fortran part is used for the forecasts computations. It consists of two methods: Load Transfer Coupling Curve Fitting (LTCCF) and load Forecast Using Curve Shape Clustering (FUCSC). LTCCF is used to 'correct' the contaminated data because of load transfer among neighboring distribution areas. FUCSC uses curve shape clustering to forecast the distribution loads of small areas. The forecast for each small area is achieved by using the shape of corresponding cluster curve. The comparison of forecasted loads of the area with historical data will be used as a tool for the correction of the estimated horizon load. The Visual Basic part is used to provide flexible interactive user-friendly environment. (author). 5 refs., 3 figs

  4. Load research manual. Volume 1. Load research procedures

    Energy Technology Data Exchange (ETDEWEB)

    Brandenburg, L.; Clarkson, G.; Grund, Jr., C.; Leo, J.; Asbury, J.; Brandon-Brown, F.; Derderian, H.; Mueller, R.; Swaroop, R.

    1980-11-01

    This three-volume manual presents technical guidelines for electric utility load research. Special attention is given to issues raised by the load data reporting requirements of the Public Utility Regulatory Policies Act of 1978 and to problems faced by smaller utilities that are initiating load research programs. In Volumes 1 and 2, procedures are suggested for determining data requirements for load research, establishing the size and customer composition of a load survey sample, selecting and using equipment to record customer electricity usage, processing data tapes from the recording equipment, and analyzing the data. Statistical techniques used in customer sampling are discussed in detail. The costs of load research also are estimated, and ongoing load research programs at three utilities are described. The manual includes guides to load research literature and glossaries of load research and statistical terms.

  5. Blinded by the load: attention, awareness and the role of perceptual load.

    Science.gov (United States)

    Lavie, Nilli; Beck, Diane M; Konstantinou, Nikos

    2014-05-05

    What is the relationship between attention and conscious awareness? Awareness sometimes appears to be restricted to the contents of focused attention, yet at other times irrelevant distractors will dominate awareness. This contradictory relationship has also been reflected in an abundance of discrepant research findings leading to an enduring controversy in cognitive psychology. Lavie's load theory of attention suggests that the puzzle can be solved by considering the role of perceptual load. Although distractors will intrude upon awareness in conditions of low load, awareness will be restricted to the content of focused attention when the attended information involves high perceptual load. Here, we review recent evidence for this proposal with an emphasis on the various subjective blindness phenomena, and their neural correlates, induced by conditions of high perceptual load. We also present novel findings that clarify the role of attention in the response to stimulus contrast. Overall, this article demonstrates a critical role for perceptual load across the spectrum of perceptual processes leading to awareness, from the very early sensory responses related to contrast detection to explicit recognition of semantic content.

  6. Subcriticality calculations for the FFTF reverse approach to critical experiment

    International Nuclear Information System (INIS)

    Selby, D.L.; Flanagan, G.F.

    1975-01-01

    The reverse approach to critical (RAC) experiments were performed in the ZPR-IX critical facility at Argonne National Laboratory. One of the major objectives of this project is to determine the adequacy of the low-level flux monitor (LLFM) detectors for initial loading of the Fast Flux Test Facility (FFTF). 5 references

  7. Prevention of criticality accidents

    International Nuclear Information System (INIS)

    Canavese, S.I.

    1982-01-01

    These notes used in the postgraduate course on Radiological Protection and Nuclear Safety discuss macro-and microscopic nuclear constants for fissile materials systems. Critical systems: their definition; criteria to analyze the critical state; determination of the critical size; analysis of practical problems about prevention of criticality. Safety of isolated units and of sets of units. Application of standards. Conception of facilities from the criticality control view point. (author) [es

  8. Load theory behind the wheel; perceptual and cognitive load effects.

    Science.gov (United States)

    Murphy, Gillian; Greene, Ciara M

    2017-09-01

    Perceptual Load Theory has been proposed as a resolution to the longstanding early versus late selection debate in cognitive psychology. There is much evidence in support of Load Theory but very few applied studies, despite the potential for the model to shed light on everyday attention and distraction. Using a driving simulator, the effect of perceptual and cognitive load on drivers' visual search was assessed. The findings were largely in line with Load Theory, with reduced distractor processing under high perceptual load, but increased distractor processing under high cognitive load. The effect of load on driving behaviour was also analysed, with significant differences in driving behaviour under perceptual and cognitive load. In addition, the effect of perceptual load on drivers' levels of awareness was investigated. High perceptual load significantly increased inattentional blindness and deafness, for stimuli that were both relevant and irrelevant to driving. High perceptual load also increased RTs to hazards. The current study helps to advance Load Theory by illustrating its usefulness outside of traditional paradigms. There are also applied implications for driver safety and roadway design, as the current study suggests that perceptual and cognitive load are important factors in driver attention. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  9. Euler Strut: A Mechanical Analogy for Dynamics in the Vicinity of a Critical Point

    Science.gov (United States)

    Bobnar, Jaka; Susman, Katarina; Parsegian, V. Adrian; Rand, Peter R.; Cepic, Mojca; Podgornik, Rudolf

    2011-01-01

    An anchored elastic filament (Euler strut) under an external point load applied to its free end is a simple model for a second-order phase transition. In the static case, a load greater than the critical load causes a Euler buckling instability, leading to a change in the filament's shape. The analysis of filament dynamics with an external point…

  10. Load handling gripper

    International Nuclear Information System (INIS)

    Holloway, C.

    1982-01-01

    An apparatus for releasably engaging and moving workpieces comprises pivotable gripper jaws with a spring-loaded plunger to maintain the jaws in a closed condition. The plunger is slidable in a bore in a housing and the end of the plunger remote from the jaws cooperates with a blind end of the bore to provide a gas cushion. A rod in conjunction with a backplate (not shown) are provided to cause the jaws to open and release a workpiece on axial movement of the housing in a first direction through a predetermined distance and releasable locking means maintain the jaws in an open condition. On axial movement of the housing in the reverse direction the locking means are released to allow the spring-loaded plunger to return to a position to close to jaws. (author)

  11. Heavy-Load Lifting

    DEFF Research Database (Denmark)

    Bloomquist, Kira; Oturai, Peter; Steele, Megan L

    2018-01-01

    of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal....... repetition maximum (RM), two sets of 15-20 repetitions) and heavy-load (85-90% 1RM, three sets of 5-8 repetition) upper-extremity resistance exercise separated by a one-week wash-out period. Swelling was determined by bioimpedance spectroscopy and dual energy x-ray absorptiometry, with breast cancer......-related lymphedema symptoms (heaviness, swelling, pain, tightness) reported using a numeric rating scale (0-10). Order of low- versus heavy-load was randomized. All outcomes were assessed pre-, immediately post-, and 24- and 72-hours post-exercise. Generalized estimating equations were used to evaluate changes over...

  12. Physical Modelling of Bucket Foundations Subjected to Axial Loading

    DEFF Research Database (Denmark)

    Vaitkunaite, Evelina

    Compared to oil and gas structures, marine renewable energy devices are usually much lighter, operate in shallower waters and are subjected to severe cyclic loading and dynamic excitations. These factors result in different structural behaviours. Bucket foundations are a potentially cost......-effective solution for various offshore structures, and not least marine renewables. The present thesis focuses on several critical design problems related to the behaviour of bucket foundations exposed to tensile loading. Among those are the soil-structure interface parameters, tensile loading under various...

  13. Progressive buckling under both constant axial load and cyclic distortion

    International Nuclear Information System (INIS)

    Clement, G.; Acker, D.; Lebey, J.

    1988-09-01

    Thin structures submitted to compressive loads must be carefully designed to avoid any risk of ruin by buckling. The aim of this paper is, first, to evidence that the critical buckling load may be notably lowered when cyclic strains are added to the compressive load and, secondly, to propose a practical rule of prevention against the ruin due to the progressive buckling phenomenon. This rule is validated by the results of numerous tests related to the entire range of modes of buckling (i.e. from fully plastic to fully elastic). Practical cases of interest for its use could mainly be those where cyclic thermal stresses are involved

  14. 1.5 MW RF Load for ITER

    International Nuclear Information System (INIS)

    Ives, Robert Lawrence; Marsden, David; Collins, George; Karimov, Rasul; Mizuhara, Max; Neilson, Jeffrey

    2016-01-01

    Calabazas Creek Research, Inc. developed a 1.5 MW RF load for the ITER fusion research facility currently under construction in France. This program leveraged technology developed in two previous SBIR programs that successfully developed high power RF loads for fusion research applications. This program specifically focused on modifications required by revised technical performance, materials, and assembly specification for ITER. This program implemented an innovative approach to actively distribute the RF power inside the load to avoid excessive heating or arcing associated with constructive interference. The new design implemented materials and assembly changes required to meet specifications. Critical components were built and successfully tested during the program.

  15. 1.5 MW RF Load for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Ives, Robert Lawrence [Calabazas Creek Research, Inc., San Mateo, CA (United States); Marsden, David [Calabazas Creek Research, Inc., San Mateo, CA (United States); Collins, George [Calabazas Creek Research, Inc., San Mateo, CA (United States); Karimov, Rasul [Calabazas Creek Research, Inc., San Mateo, CA (United States); Mizuhara, Max [Calabazas Creek Research, Inc., San Mateo, CA (United States); Neilson, Jeffrey [Lexam Research, Redwood City, CA (United States)

    2016-09-01

    Calabazas Creek Research, Inc. developed a 1.5 MW RF load for the ITER fusion research facility currently under construction in France. This program leveraged technology developed in two previous SBIR programs that successfully developed high power RF loads for fusion research applications. This program specifically focused on modifications required by revised technical performance, materials, and assembly specification for ITER. This program implemented an innovative approach to actively distribute the RF power inside the load to avoid excessive heating or arcing associated with constructive interference. The new design implemented materials and assembly changes required to meet specifications. Critical components were built and successfully tested during the program.

  16. Fuel element loading system

    International Nuclear Information System (INIS)

    Arya, S.P; s.

    1978-01-01

    A nuclear fuel element loading system is described which conveys a plurality of fuel rods to longitudinal passages in fuel elements. Conveyor means successively position the fuel rods above the longitudinal passages in axial alignment therewith and adapter means guide the fuel rods from the conveyor means into the longitudinal passages. The fuel elements are vibrated to cause the fuel rods to fall into the longitudinal passages through the adapter means

  17. TFTR generator load assessment

    International Nuclear Information System (INIS)

    Heck, F.M.

    1975-10-01

    Typical experimental load demands on the TFTR generators are illustrated based on the electrical characteristics of the field coils, the coil leads, the main bus work, the various auxiliary bus work, the rectifiers, and transformers. The generator MW capacities are shown to be adequate for the proposed experimental operations with allowances made for variations in the final designs. The generator MVA capacities are shown to be adequate provided portions of the TF and EF rectifiers are freewheeled at selected times

  18. Load responsive hydrodynamic bearing

    Science.gov (United States)

    Kalsi, Manmohan S.; Somogyi, Dezso; Dietle, Lannie L.

    2002-01-01

    A load responsive hydrodynamic bearing is provided in the form of a thrust bearing or journal bearing for supporting, guiding and lubricating a relatively rotatable member to minimize wear thereof responsive to relative rotation under severe load. In the space between spaced relatively rotatable members and in the presence of a liquid or grease lubricant, one or more continuous ring shaped integral generally circular bearing bodies each define at least one dynamic surface and a plurality of support regions. Each of the support regions defines a static surface which is oriented in generally opposed relation with the dynamic surface for contact with one of the relatively rotatable members. A plurality of flexing regions are defined by the generally circular body of the bearing and are integral with and located between adjacent support regions. Each of the flexing regions has a first beam-like element being connected by an integral flexible hinge with one of the support regions and a second beam-like element having an integral flexible hinge connection with an adjacent support region. A least one local weakening geometry of the flexing region is located intermediate the first and second beam-like elements. In response to application of load from one of the relatively rotatable elements to the bearing, the beam-like elements and the local weakening geometry become flexed, causing the dynamic surface to deform and establish a hydrodynamic geometry for wedging lubricant into the dynamic interface.

  19. Distraction and mind-wandering under load.

    Science.gov (United States)

    Forster, Sophie

    2013-01-01

    Attention research over the last several decades has provided rich insights into the determinants of distraction, including distractor characteristics, task features, and individual differences. Load Theory represented a particularly important breakthrough, highlighting the critical role of the level and nature of task-load in determining both the efficiency of distractor rejection and the stage of processing at which this occurs. However, until recently studies of distraction were restricted to those measuring rather specific forms of distraction by external stimuli which I argue that, although intended to be irrelevant, were in fact task-relevant. In daily life, attention may be distracted by a wide range of stimuli, which may often be entirely unrelated to any task being performed, and may include not only external stimuli but also internally generated stimuli such as task-unrelated thoughts. This review outlines recent research examining these more general, entirely task-irrelevant, forms of distraction within the framework of Load Theory. I discuss the relation between different forms of distraction, and the universality of load effects across different distractor types and individuals.

  20. Distraction and mind-wandering under load

    Directory of Open Access Journals (Sweden)

    Sophie eForster

    2013-05-01

    Full Text Available Attention research over the last several decades has provided rich insights into the determinants of distraction, including distractor characteristics, task features and individual differences. Load Theory represented a particularly important breakthrough, highlighting the critical role of the level and nature of task load in determining both the efficiency of distractor rejection and the stage of processing at which this occurs. However, until recently studies of distraction were restricted to those measuring rather specific forms of distraction by external stimuli which I argue that, although intended to be irrelevant, were in fact task-relevant. In daily life, attention may be distracted by a wide range of stimuli, which may often be entirely unrelated to any task being performed, and may include not only external stimuli but also internally generated stimuli such as task-unrelated thoughts. This review outlines recent research examining these more general, entirely task-irrelevant, forms of distraction within the framework of Load Theory. I discuss the relation between different forms of distraction, and the universality of load effects across different distractor types and individuals.

  1. Preclosure Criticality Analysis Process Report

    International Nuclear Information System (INIS)

    Thomas, D.A.

    1999-01-01

    The design approach for criticality of the disposal container and waste package will be dictated by existing regulatory requirements. This conclusion is based on the fact that preclosure operations and facilities have significant similarities to existing facilities and operations currently regulated by the NRC. The major difference would be the use of a risk-informed approach with burnup credit. This approach could reduce licensing delays and costs of the repository. The probability of success for this proposed seamless licensing strategy is increased, since there is precedence of regulation (10 CFR Part 63 and NUREG 1520) and commercial precedence for allowing burnup credit at sites similar to Yucca Mountain during preclosure. While NUREG 1520 is not directly applicable to a facility for handling spent nuclear fuel, the risk-informed approach to criticality analysis in NUREG 1520 is considered indicative of how the NRC will approach risk-informed criticality analysis at spent fuel facilities in the future. The types of design basis events which must be considered during the criticality safety analysis portion of the Integrated Safety Analysis (ISA) are those events which result in unanticipated moderation, loss of neutron absorber, geometric changes in the critical system, or administrative errors in waste form placement (loading) of the disposal container. The specific events to be considered must be based on the review of the system's design, as discussed in Section 3.2. A transition of licensing approach (e.g., deterministic versus risk-informed, performance-based) is not obvious and will require analysis. For commercial spent nuclear fuel, the probability of interspersed moderation may be low enough to allow nearly the same Critical Limit for both preclosure and postclosure, though an administrative margin will be applied to preclosure and possibly not to postclosure. Similarly the Design Basis Events for the waste package may be incredible and therefore not

  2. Preclosure Criticality Analysis Process Report

    International Nuclear Information System (INIS)

    Thomas, D.A.

    1999-01-01

    The design approach for criticality of the disposal container and waste package will be dictated by existing regulatory requirements. This conclusion is based on the fact that preclosure operations and facilities have significant similarities to existing facilities and operations currently regulated by the NRC. The major difference would be the use of a risk-informed approach with burnup credit. This approach could reduce licensing delays and costs of the repository. The probability of success for this proposed seamless licensing strategy is increased, since there is precedence of regulation (10 CFR Part 63 and NUREG 1520) and commercial precedence for allowing burnup credit at sites similar to Yucca Mountain during preclosure. While NUREG 1520 is not directly applicable to a facility for handling spent nuclear fuel, the risk-informed approach to criticality analysis in NUREG 1520 is considered indicative of how the NRC will approach risk-informed criticality analysis at spent fuel facilities in the future. The types of design basis events which must be considered during the criticality safety analysis portion of the Integrated Safety Analysis (ISA) are those events which result in unanticipated moderation, loss of neutron absorber, geometric changes in the critical system, or administrative errors in waste form placement (loading) of the disposal container. The specific events to be considered must be based on the review of the system's design, as discussed in Section 3.2. A transition of licensing approach (e.g., deterministic versus risk-informed, performance-based) is not obvious and will require analysis. For commercial spent nuclear fuel, the probability of interspersed moderation may be low enough to allow nearly the same Critical Limit for both preclosure and postclosure, though an administrative margin will be applied to preclosure and possibly not to postclosure. Similarly the Design Basis Events for the waste package may be incredible and therefore not

  3. Plastic limit loads for cylindrical shell intersections under combined loading

    International Nuclear Information System (INIS)

    Skopinsky, V.N.; Berkov, N.A.; Vogov, R.A.

    2015-01-01

    In this research, applied methods of nonlinear analysis and results of determining the plastic limit loads for shell intersection configurations under combined internal pressure, in-plane moment and out-plane moment loadings are presented. The numerical analysis of shell intersections is performed using the finite element method, geometrically nonlinear shell theory in quadratic approximation and plasticity theory. For determining the load parameter of proportional combined loading, the developed maximum criterion of rate of change of relative plastic work is employed. The graphical results for model of cylindrical shell intersection under different two-parameter combined loadings (as generalized plastic limit load curves) and three-parameter combined loading (as generalized plastic limit load surface) are presented on the assumption that the internal pressure, in-plane moment and out-plane moment loads were applied in a proportional manner. - Highlights: • This paper presents nonlinear two-dimensional FE analysis for shell intersections. • Determining the plastic limit loads under combined loading is considered. • Developed maximum criterion of rate of change of relative plastic work is employed. • Plastic deformation mechanism in shell intersections is discussed. • Results for generalized plastic limit load curves of branch intersection are presented

  4. Critical thinking: Not all that critical

    Directory of Open Access Journals (Sweden)

    Bruce Dietrick Price

    2016-09-01

    Full Text Available Critical Thinking basically says to be suspicious of everything, except the fad known as Critical Thinking. It is perhaps best understood as a new and watered-down version of an earlier fad called Deconstruction. That was just a fancy word for debunking. After you strip away all the high-minded rhetoric, Critical Thinking is typically used to tell students that they should not trust conventional wisdom, tradition, religion, parents, and all that irrelevant, old-fashioned stuff. Critical Thinking, somewhat surprisingly, also turns out to be highly contemptuous of facts and knowledge. The formulation in public schools goes like this: children must learn how to think, not what to think. WHAT is, of course, all the academic content and scholarly knowledge that schools used to teach.

  5. Critical/non-critical system methodology report

    International Nuclear Information System (INIS)

    1989-01-01

    The method used to determine how the waste Isolation Pilot Plant (WIPP) facilities/systems were classified as critical or non-critical to the receipt of CH waste is described within this report. All WIPP critical facilities/systems are listed in the Operational Readiness Review Dictionary. Using the Final Safety Analysis Report (FSAR) as a guide to define the boundaries of the facilities/systems, a direct correlation of the ORR Dictionary to the FSAR can be obtained. The critical facilities/systems are those which are directly related to or have a critical support role in the receipt of CH waste. The facility/systems must meet one of the following requirements to be considered critical: (a) confinement or measure of the release of radioactive materials; (b) continued receipt and/or storage of transuranic waste (TRU) without an interruption greater than one month according to the shipping plan schedule; (c) the environmental and occupational safety of personnel meets the established site programs; and (d) the physical security of the WIPP facilities

  6. California Condor Critical Habitat

    Data.gov (United States)

    California Natural Resource Agency — These Data identify (in general) the areas where critical habitat for the California Condor occur. Critical habitat for the species consists of the following 10...

  7. Surgical Critical Care Initiative

    Data.gov (United States)

    Federal Laboratory Consortium — The Surgical Critical Care Initiative (SC2i) is a USU research program established in October 2013 to develop, translate, and validate biology-driven critical care....

  8. Critical Care Team

    Science.gov (United States)

    ... often uphold the patient's wishes. The critical care nurse becomes an important part of decision-making with the patient, the family and the care team. A registered nurse (RN) who is certified in critical care is ...

  9. The Ways of Criticism

    NARCIS (Netherlands)

    Krabbe, Erik C. W.; van Laar, Jan Albert

    This paper attempts to systematically characterize critical reactions in argumentative discourse, such as objections, critical questions, rebuttals, refutations, counterarguments, and fallacy charges, in order to contribute to the dialogical approach to argumentation. We shall make use of four

  10. Education by Criticism.

    Science.gov (United States)

    Tanner, Stephen L.

    1986-01-01

    Argues that students should exercise criticism in the classroom, but this criticism should not take the form of mere training in technical skills, indoctrination into a particular conceptual system, or theoretical speculation ungrounded in reality. (SRT)

  11. Nutrient and Coliform Loading (NCL)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is a database of available fecal coliform bacteria, fecal streptococci bacteria, and nutrient loading data. Loading for contaminants other than fecal coliform...

  12. Performance of multifilamentary Nb3Sn under mechanical load

    International Nuclear Information System (INIS)

    Easton, D.S.; Schwall, R.E.

    1976-11-01

    The critical current density of commercial multifilamentary Nb 3 Sn conductor has been measured during the application of uniaxial tension at 4.2 0 K and after bending at room temperature. Significant reductions in the critical current density J/sub c/ occurred under uniaxial loading. Results are presented for a monolithic conductor manufactured by the bronze diffusion technique and for cable conductors formed by the tin-dip technique

  13. Toward critical bioethics.

    Science.gov (United States)

    Árnason, Vilhjálmur

    2015-04-01

    This article deals with the question as to what makes bioethics a critical discipline. It considers different senses of criticism and evaluates their strengths and weaknesses. A primary method in bioethics as a philosophical discipline is critical thinking, which implies critical evaluation of concepts, positions, and arguments. It is argued that the type of analytical criticism that restricts its critical role to critical thinking of this type often suffers from other intellectual flaws. Three examples are taken to demonstrate this: premature criticism, uncritical self-understanding of theoretical assumptions, and narrow framing of bioethical issues. Such flaws can lead both to unfair treatment of authors and to uncritical discussion of topics. In this context, the article makes use of Häyry's analysis of different rationalities in bioethical approaches and argues for the need to recognize the importance of communicative rationality for critical bioethics. A radically different critical approach in bioethics, rooted in social theory, focuses on analyses of power relations neglected in mainstream critical thinking. It is argued that, although this kind of criticism provides an important alternative in bioethics, it suffers from other shortcomings that are rooted in a lack of normative dimensions. In order to complement these approaches and counter their shortcomings, there is a need for a bioethics enlightened by critical hermeneutics. Such hermeneutic bioethics is aware of its own assumptions, places the issues in a wide context, and reflects critically on the power relations that stand in the way of understanding them. Moreover, such an approach is dialogical, which provides both a critical exercise of speech and a normative dimension implied in the free exchange of reasons and arguments. This discussion is framed by Hedgecoe's argument that critical bioethics needs four elements: to be empirically rooted, theory challenging, reflexive, and politely skeptical.

  14. Cognitive Load and Strategic Sophistication

    OpenAIRE

    Allred, Sarah; Duffy, Sean; Smith, John

    2013-01-01

    We study the relationship between the cognitive load manipulation and strategic sophistication. The cognitive load manipulation is designed to reduce the subject's cognitive resources that are available for deliberation on a choice. In our experiment, subjects are placed under a large cognitive load (given a difficult number to remember) or a low cognitive load (given a number which is not difficult to remember). Subsequently, the subjects play a one-shot game then they are asked to recall...

  15. Research of Impact Load in Large Electrohydraulic Load Simulator

    Directory of Open Access Journals (Sweden)

    Yongguang Liu

    2014-01-01

    Full Text Available The stronger impact load will appear in the initial phase when the large electric cylinder is tested in the hardware-in-loop simulation. In this paper, the mathematical model is built based on AMESim, and then the reason of the impact load is investigated through analyzing the changing tendency of parameters in the simulation results. The inhibition methods of impact load are presented according to the structural invariability principle and applied to the actual system. The final experimental result indicates that the impact load is inhibited, which provides a good experimental condition for the electric cylinder and promotes the study of large load simulator.

  16. Demand Response Load Following of Source and Load Systems

    DEFF Research Database (Denmark)

    Hu, Jianqiang; Cao, Jinde; Yong, Taiyou

    2017-01-01

    This paper presents a demand response load following strategy for an interconnected source and load system, in which we utilize traditional units and population of cooling thermostatically controlled loads (TCLs) to follow the mismatched power caused by the load activities and the renewable power...... injection in real time. In the demand side of power systems, these TCLs are often affiliated to a bus load agent and can be aggregated to multiple TCL aggregators. Firstly, aggregate evaluation of the TCL aggregator is carried out based on a bilinear aggregate model so as to derive the available regulation...

  17. Reimagining Critical Theory

    Science.gov (United States)

    Rexhepi, Jevdet; Torres, Carlos Alberto

    2011-01-01

    This paper discusses Critical Theory, a model of theorizing in the field of the political sociology of education. We argue for a "reimagined" Critical Theory to herald an empowering, liberatory education that fosters curiosity and critical thinking, and a means for successful bottom-up, top-down political engagement. We present arguments…

  18. Foundations for Critical Thinking

    Science.gov (United States)

    Bers, Trudy; Chun, Marc; Daly, William T.; Harrington, Christine; Tobolowsky, Barbara F.

    2015-01-01

    "Foundations for Critical Thinking" explores the landscape of critical-thinking skill development and pedagogy through foundational chapters and institutional case studies involving a range of students in diverse settings. By establishing a link between active learning and improved critical thinking, this resource encourages all higher…

  19. Creating a Critical Thinker

    Science.gov (United States)

    Piergiovanni, Polly R.

    2014-01-01

    A college education is expected to improve students' critical thinking skills. Keeping students active in class--through writing activities and class discussion--has been shown to help students think critically. In this article, creative hands-on activities, which are common in engineering courses, are shown to improve students' critical thinking…

  20. International critical perspectives

    NARCIS (Netherlands)

    Sambrook, S.A.; Poell, R.F.

    2014-01-01

    The Problem Critical perspectives on human resource development (HRD) have emerged, across Europe and America, hailed as the future of the field. However, we note the paucity of critical perspectives globally, the problematic dominance of critical HRD activities in Western sites of theory and

  1. Load Estimation from Modal Parameters

    DEFF Research Database (Denmark)

    Aenlle, Manuel López; Brincker, Rune; Fernández, Pelayo Fernández

    2007-01-01

    In Natural Input Modal Analysis the modal parameters are estimated just from the responses while the loading is not recorded. However, engineers are sometimes interested in knowing some features of the loading acting on a structure. In this paper, a procedure to determine the loading from a FRF m...

  2. High loading uranium plate

    International Nuclear Information System (INIS)

    Wiencek, T.C.; Domagala, R.F.; Thresh, H.R.

    1990-01-01

    Two embodiments of a high uranium fuel plate are disclosed which contain a meat comprising structured uranium compound confined between a pari of diffusion bonded ductile metal cladding plates uniformly covering the meat, the meat hiving a uniform high fuel loading comprising a content of uranium compound greater than about 45 Vol. % at a porosity not greater than about 10 Vol. %. In a first embodiment, the meat is a plurality of parallel wires of uranium compound. In a second embodiment, the meat is a dispersion compact containing uranium compound. The fuel plates are fabricated by a hot isostatic pressing process

  3. Android Fully Loaded

    CERN Document Server

    Huddleston, Rob

    2012-01-01

    Fully loaded with the latest tricks and tips on your new Android! Android smartphones are so hot, they're soaring past iPhones on the sales charts. And the second edition of this muscular little book is equally impressive--it's packed with tips and tricks for getting the very most out of your latest-generation Android device. Start Facebooking and tweeting with your Android mobile, scan barcodes to get pricing and product reviews, download your favorite TV shows--the book is positively bursting with practical and fun how-tos. Topics run the gamut from using speech recognition, location-based m

  4. Spreading the load

    International Nuclear Information System (INIS)

    Hay, Greg

    1999-01-01

    This article examines the management of power demand by the regional electricity companies in the United Kingdom so that consumers use most power at times when the pool price is at its lowest. The use of teleswitching for load management, the control of the heating of large residential buildings, the power demand of supermarkets with 24hr opening, financial incentives, and the forecasting of demand are discussed. Details are given of the work of the operational forecasting team, and the matching of demand with generators availability by the scheduling team of the National Grid. (UK)

  5. Spatial electric load forecasting

    CERN Document Server

    Willis, H Lee

    2002-01-01

    Containing 12 new chapters, this second edition contains offers increased-coverage of weather correction and normalization of forecasts, anticipation of redevelopment, determining the validity of announced developments, and minimizing risk from over- or under-planning. It provides specific examples and detailed explanations of key points to consider for both standard and unusual utility forecasting situations, information on new algorithms and concepts in forecasting, a review of forecasting pitfalls and mistakes, case studies depicting challenging forecast environments, and load models illustrating various types of demand.

  6. Fuel loads and fuel type mapping

    Science.gov (United States)

    Chuvieco, Emilio; Riaño, David; Van Wagtendonk, Jan W.; Morsdof, Felix; Chuvieco, Emilio

    2003-01-01

    Correct description of fuel properties is critical to improve fire danger assessment and fire behaviour modeling, since they guide both fire ignition and fire propagation. This chapter deals with properties of fuel that can be considered static in short periods of time: biomass loads, plant geometry, compactness, etc. Mapping these properties require a detail knowledge of vegetation vertical and horizontal structure. Several systems to classify the great diversity of vegetation characteristics in few fuel types are described, as well as methods for mapping them with special emphasis on those based on remote sensing images.

  7. Mitigating the Long term Operating Extreme Load through Active Control

    International Nuclear Information System (INIS)

    Koukoura, Christina; Natarajan, Anand

    2014-01-01

    The parameters influencing the long term extreme operating design loads are identified through the implementation of a Design of Experiment (DOE) method. A function between the identified critical factors and the ultimate out-of-plane loads on the blade is determined. Variations in the initial blade azimuth location are shown to affect the extreme blade load magnitude during operation in normal turbulence wind input. The simultaneously controlled operation of generator torque variation and pitch variation at low blade pitch angles is detected to be responsible for very high loads acting on the blades. Through gain scheduling of the controller (modifications of the proportional Kp and the integral K gains) the extreme loads are mitigated, ensuring minimum instantaneous variations in the power production for operation above rated wind speed. The response of the blade load is examined for different values of the integral gain as resulting in rotor speed error and the rate of change of rotor speed. Based on the results a new load case for the simulation of extreme loads during normal operation is also presented

  8. Transportable criticality alarm system

    International Nuclear Information System (INIS)

    Clem, W.E.

    1988-09-01

    The Transportable Criticality Alarm System was developed at the Hanford Site in 1982 to comply with the requirements of US Department of Energy Order DOE 5480.1, 12/18/80, and ANSI/ANS-8.3- 1979. The portable unit that it replaced failed to comply with the new requirements in that it did not provide the necessary warning of malfunctions, nor did it provide the Hanford Site standard criticality alarm signal. Modern technology allowed the Transportable Criticality Alarm System to comply with the criticality requirements cited and to incorporate other features that make it more usable, maintainable, and reliable. The Transportable Criticality Alarm System (TCAS) provides temporary criticality coverage in manned areas where the facility criticality alarm system is not operable. This gamma radiation-sensitive system has been in use for the past 6 yr at the Hanford Site. 2 refs., 4 figs., 1 tab

  9. Criticality handbook. Pt. 1

    International Nuclear Information System (INIS)

    Heinicke, W.; Krug, H.; Thomas, W.; Weber, W.; Gmal, B.

    1985-12-01

    The GRS Criticality Handbook is intended as a source of information on criticality problems for the persons concerned in industry, authorities, or research laboratories. It is to serve as a guide allowing quick and appropriate evaluation of criticality problems during design or erection of nuclear installations. This present issue replaces the one published in 1979, presenting revised and new data in a modified construction, but within the framework of the proven basic structure of the Handbook. Some fundamental knowledge is required of criticality problems and the relevant terms and definitions of nuclear safety, in order to fully deploy the information given. Part 1 of the Handbook therefore first introduces terminology and definitions, followed by experimental methods and calculation models for criticality calculations. The next chapters deal with the function and efficiency of neutron reflectors and neutron absorbers, measuring methods for criticality monitoring, organisational safety measures, and criticality accidents and their subsequent analysis. (orig./HP) [de

  10. Load Control System Reliability

    Energy Technology Data Exchange (ETDEWEB)

    Trudnowski, Daniel [Montana Tech of the Univ. of Montana, Butte, MT (United States)

    2015-04-03

    This report summarizes the results of the Load Control System Reliability project (DOE Award DE-FC26-06NT42750). The original grant was awarded to Montana Tech April 2006. Follow-on DOE awards and expansions to the project scope occurred August 2007, January 2009, April 2011, and April 2013. In addition to the DOE monies, the project also consisted of matching funds from the states of Montana and Wyoming. Project participants included Montana Tech; the University of Wyoming; Montana State University; NorthWestern Energy, Inc., and MSE. Research focused on two areas: real-time power-system load control methodologies; and, power-system measurement-based stability-assessment operation and control tools. The majority of effort was focused on area 2. Results from the research includes: development of fundamental power-system dynamic concepts, control schemes, and signal-processing algorithms; many papers (including two prize papers) in leading journals and conferences and leadership of IEEE activities; one patent; participation in major actual-system testing in the western North American power system; prototype power-system operation and control software installed and tested at three major North American control centers; and, the incubation of a new commercial-grade operation and control software tool. Work under this grant certainly supported the DOE-OE goals in the area of “Real Time Grid Reliability Management.”

  11. From Critical Theory to Critical Hermeneutics

    Directory of Open Access Journals (Sweden)

    Øjvind Larsen

    2014-06-01

    Full Text Available From their beginning in the 1930s, critical theory and the Frankfurt school had their focus on a critique of disturbed social relations in western society dominated by totalitarian political regimes like Stalinism, Fascism, Nazism, and by capitalism as an oppressive and destructive economic system and culture. Now, 80 years later, this has all become history and thus it is time to leave the concept of critical theory behind us, and instead bring the concept of critique to a broader theoretical framework like hermeneutics. This allows the possibility of retaining the theoretical intentions of the old Frankfurt school and at the same time there will be no boundaries by specific dominant theoretical perspectives. In this paper, such a framework for a critical hermeneutics is discussed on the basis of Weber’s, Gadamer’s, and Habermas’ theories on hermeneutics within the social sciences.

  12. Missing a trick: Auditory load modulates conscious awareness in audition.

    Science.gov (United States)

    Fairnie, Jake; Moore, Brian C J; Remington, Anna

    2016-07-01

    In the visual domain there is considerable evidence supporting the Load Theory of Attention and Cognitive Control, which holds that conscious perception of background stimuli depends on the level of perceptual load involved in a primary task. However, literature on the applicability of this theory to the auditory domain is limited and, in many cases, inconsistent. Here we present a novel "auditory search task" that allows systematic investigation of the impact of auditory load on auditory conscious perception. An array of simultaneous, spatially separated sounds was presented to participants. On half the trials, a critical stimulus was presented concurrently with the array. Participants were asked to detect which of 2 possible targets was present in the array (primary task), and whether the critical stimulus was present or absent (secondary task). Increasing the auditory load of the primary task (raising the number of sounds in the array) consistently reduced the ability to detect the critical stimulus. This indicates that, at least in certain situations, load theory applies in the auditory domain. The implications of this finding are discussed both with respect to our understanding of typical audition and for populations with altered auditory processing. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  13. Examining the Relationships of Different Cognitive Load Types Related to User Interface in Web-Based Instruction

    Science.gov (United States)

    Cheon, Jongpil; Grant, Michael

    2012-01-01

    This study proposes a new instrument to measure cognitive load types related to user interface and demonstrates theoretical assumptions about different load types. In reconsidering established cognitive load theory, the inadequacies of the theory are criticized in terms of the adaption of learning efficiency score and distinction of cognitive load…

  14. A report on the first loading of ZENITH

    International Nuclear Information System (INIS)

    Absalom, R.M.; Barclay, F.R.; Cameron, I.R.; Della Loggia, V.E.; Hage, W.; Kinchin, G.H.; Sanders, J.E.; Tiren, L.I.; Wilson, D.J.

    1960-12-01

    The loading to criticality of the first core of the zero energy reactor ZENITH, and the results of the subsequent experimental programme are described. The composition of the reactor core corresponds to graphite: U235 and Th232: U235 atomic ratios of 3843 and 9.51 respectively. (author)

  15. A report on the first loading of ZENITH

    Energy Technology Data Exchange (ETDEWEB)

    Absalom, R M; Barclay, F R; Cameron, I R; Della Loggia, V E; Hage, W; Kinchin, G H; Sanders, J E; Tiren, L I; Wilson, D J [Industrial Power Reactors Division, Atomic Energy Establishment, Winfrith, Dorchester, Dorset (United Kingdom)

    1960-12-15

    The loading to criticality of the first core of the zero energy reactor ZENITH, and the results of the subsequent experimental programme are described. The composition of the reactor core corresponds to graphite: U235 and Th232: U235 atomic ratios of 3843 and 9.51 respectively. (author)

  16. Lighting Rural India : Load Segregation Eexperience in Selected States

    OpenAIRE

    Khanna, Ashish; Mukherjee, Mohua; Banerjee, Sudeshna Ghosh; Saraswat, Kavita; Khurana, Mani

    2014-01-01

    Socioeconomic development of the rural populace is critical to India achieving its stated objective of inclusive growth. It is widely accepted that access to a reliable and sufficient power supply is a key enabler of rural economic growth. Traditionally, India's rural power supply has been restricted by having feeders to villages serve both agriculture and household loads. Because agric...

  17. Dynamic modelling of heavy metals - time scales and target loads

    NARCIS (Netherlands)

    Posch, M.; Vries, de W.

    2009-01-01

    Over the past decade steady-state methods have been developed to assess critical loads of metals avoiding long-term risks in view of food quality and eco-toxicological effects on organisms in soils and surface waters. However, dynamic models are needed to estimate the times involved in attaining a

  18. Conditional Stochastic Processes Applied to Wave Load Predictions

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher

    2015-01-01

    The concept of conditional stochastic processes provides a powerful tool for evaluation and estimation of wave loads on ships and offshore structures. This article first considers conditional waves with a focus on critical wave episodes. Then the inherent uncertainty in the results is illustrated...

  19. Model-Based Load Estimation for Predictive Condition Monitoring of Wind Turbines

    DEFF Research Database (Denmark)

    Perisic, Nevena; Pederen, Bo Juul; Grunnet, Jacob Deleuran

    signal is performed online, and a Load Indicator Signal (LIS) is formulated as a ratio between current estimated accumulated fatigue loads and its expected value based only on a priori knowledge (WTG dynamics and wind climate). LOT initialisation is based on a priori knowledge and can be obtained using...... programme for pre-maintenance actions. The performance of LOT is demonstrated by applying it to one of the most critical WTG components, the gearbox. Model-based load CMS for gearbox requires only standard WTG SCADA data. Direct measuring of gearbox fatigue loads requires high cost and low reliability...... measurement equipment. Thus, LOT can significantly reduce the price of load monitoring....

  20. Probabilistic model for multi-axial load combinations for wind turbines

    DEFF Research Database (Denmark)

    Dimitrov, Nikolay Krasimirov

    2016-01-01

    into a periodic part and a perturbation term, where each part has a known probability distribution. The proposed model shows good agreement with simulated data under stationary conditions, and a design load envelope based on this model is comparable to the load envelope estimated using the standard procedure...... for determining contemporaneous loads. Using examples with simulated loads on a 10 MW wind turbine,the behavior of the bending moments acting on a blade section is illustrated under different conditions.The loading direction most critical for material failure is determined using a finite-element model...

  1. Criticism and Counter-Criticism of Public Management: Strategy Models

    OpenAIRE

    Luis C. Ortigueira

    2007-01-01

    Critical control is very important in scientific management. This paper presents models of critical and counter-critical public-management strategies, focusing on the types of criticism and counter-criticism manifested in parliamentary political debates. The paper includes: (i) a normative model showing how rational criticism can be carried out; (ii) a normative model for oral critical intervention; and (iii) a general motivational strategy model for criticisms and counter-criticisms. The pap...

  2. Emergency Power For Critical Items

    Science.gov (United States)

    Young, William R.

    2009-07-01

    Natural disasters, such as hurricanes, floods, tornados, and tsunami, are becoming a greater problem as climate change impacts our environment. Disasters, whether natural or man made, destroy lives, homes, businesses and the natural environment. Such disasters can happen with little or no warning, leaving hundreds or even thousands of people without medical services, potable water, sanitation, communications and electrical services for up to several weeks. In our modern world, the need for electricity has become a necessity. Modern building codes and new disaster resistant building practices are reducing the damage to homes and businesses. Emergency gasoline and diesel generators are becoming common place for power outages. Generators need fuel, which may not be available after a disaster, but Photovoltaic (solar-electric) systems supply electricity without petroleum fuel as they are powered by the sun. Photovoltaic (PV) systems can provide electrical power for a home or business. PV systems can operate as utility interactive or stand-alone with battery backup. Determining your critical load items and sizing the photovoltaic system for those critical items, guarantees their operation in a disaster.

  3. Critical Psychologies for Critical Health Literacies

    Science.gov (United States)

    Corcoran, Tim

    2014-01-01

    Health education is largely informed by psychological theories and practices that pursue reductionist views of people learning. However, critical attention is moving to understand health in ways that reconsider relationships to context and the forms of life within which everyday living takes place. This shift is apparent in theoretical…

  4. High thermal load component

    International Nuclear Information System (INIS)

    Fuse, Toshiaki; Tachikawa, Nobuo.

    1996-01-01

    A cooling tube made of a pure copper is connected to the inner portion of an armour (heat resistant member) made of an anisotropic carbon/carbon composite (CFC) material. The CFC material has a high heat conductivity in longitudinal direction of fibers and has low conductivity in perpendicular thereto. Fibers extending in the armour from a heat receiving surface just above the cooling tube are directly connected to the cooling tube. A portion of the fibers extending from a heat receiving surface other than portions not just above the cooling tube is directly bonded to the cooling tube. Remaining fibers are disposed so as to surround the cooling tube. The armour and the cooling tube are soldered using an active metal flux. With such procedures, high thermal load components for use in a thermonuclear reactor are formed, which are excellent in a heat removing characteristic and hardly causes defects such as crackings and peeling. (I.N.)

  5. Surveillance and Critical Theory

    Directory of Open Access Journals (Sweden)

    Christian Fuchs

    2015-09-01

    Full Text Available In this comment, the author reflects on surveillance from a critical theory approach, his involvement in surveillance research and projects, and the status of the study of surveillance. The comment ascertains a lack of critical thinking about surveillance, questions the existence of something called “surveillance studies” as opposed to a critical theory of society, and reflects on issues such as Edward Snowden’s revelations, and Foucault and Marx in the context of surveillance.

  6. Extending Critical Performativity

    DEFF Research Database (Denmark)

    Spicer, André; Alvesson, Mats; Kärreman, Dan

    2016-01-01

    In this article we extend the debate about critical performativity. We begin by outlining the basic tenets of critical performativity and how this has been applied in the study of management and organization. We then address recent critiques of critical performance. We note these arguments suffer...... of public importance; engaging with non-academic groups using dialectical reasoning; scaling up insights through movement building; and propagating deliberation...

  7. Pay for load demand - electricity pricing with load demand component

    International Nuclear Information System (INIS)

    Pyrko, Jurek; Sernhed, Kerstin; Abaravicius, Juozas

    2003-01-01

    This publication is part of a project called Direct and Indirect Load Control in Buildings. Peak load problems have attracted considerable attention in Sweden during last three winters, caused by a significant decrease in available reserve power, which is a consequence of political decisions and liberalisation of the electricity market. A possible way to lower peak loads, avoiding electricity shortages and reducing electricity costs both for users and utilities, is to make customers experience the price difference during peak load periods and, in this way, become more aware of their energy consumption pattern and load demand. As of January 1st 2001, one of the Swedish energy utilities - Sollentuna Energi - operating in the Stockholm area, introduced a new electricity tariff with differentiated grid fees based on a mean value of the peak load every month. This tariff was introduced for all residential customers in the service area. The objective of this study is to investigate the extent to which a Load Demand Component, included in electricity pricing, can influence energy use and load demand in residential buildings. What are the benefits and disadvantages for customers and utilities? This paper investigates the impact of the new tariff on the utility and different types of typical residential customers, making comparisons with previous tariff. Keywords Load demand, electricity pricing, tariff, residential customers, energy behaviour

  8. Dynamical load factor of impact loaded shell structures

    International Nuclear Information System (INIS)

    Hammel, J.

    1977-01-01

    Dynamical loaded structures can be analysed by spectral representations, which usually lead to an enormous computational effort. If it is possible to find a fitting dynamical load factor, the dynamical problem can be reduced to a statical one. The computation of this statical problem is much simpler. The disadvantage is that the dynamical load factor usually leads to a very rough approximation. In this paper it will be shown, that by combination of these two methods, the approximation of the dynamical load factor can be improved and the consumption of computation time can be enormously reduced. (Auth.)

  9. Nuclear criticality predictability

    International Nuclear Information System (INIS)

    Briggs, J.B.

    1999-01-01

    As a result of lots of efforts, a large portion of the tedious and redundant research and processing of critical experiment data has been eliminated. The necessary step in criticality safety analyses of validating computer codes with benchmark critical data is greatly streamlined, and valuable criticality safety experimental data is preserved. Criticality safety personnel in 31 different countries are now using the 'International Handbook of Evaluated Criticality Safety Benchmark Experiments'. Much has been accomplished by the work of the ICSBEP. However, evaluation and documentation represents only one element of a successful Nuclear Criticality Safety Predictability Program and this element only exists as a separate entity, because this work was not completed in conjunction with the experimentation process. I believe; however, that the work of the ICSBEP has also served to unify the other elements of nuclear criticality predictability. All elements are interrelated, but for a time it seemed that communications between these elements was not adequate. The ICSBEP has highlighted gaps in data, has retrieved lost data, has helped to identify errors in cross section processing codes, and has helped bring the international criticality safety community together in a common cause as true friends and colleagues. It has been a privilege to associate with those who work so diligently to make the project a success. (J.P.N.)

  10. Critical point predication device

    International Nuclear Information System (INIS)

    Matsumura, Kazuhiko; Kariyama, Koji.

    1996-01-01

    An operation for predicting a critical point by using a existent reverse multiplication method has been complicated, and an effective multiplication factor could not be plotted directly to degrade the accuracy for the prediction. The present invention comprises a detector counting memory section for memorizing the counting sent from a power detector which monitors the reactor power, a reverse multiplication factor calculation section for calculating the reverse multiplication factor based on initial countings and current countings of the power detector, and a critical point prediction section for predicting the criticality by the reverse multiplication method relative to effective multiplication factors corresponding to the state of the reactor core previously determined depending on the cases. In addition, a reactor core characteristic calculation section is added for analyzing an effective multiplication factor depending on the state of the reactor core. Then, if the margin up to the criticality is reduced to lower than a predetermined value during critical operation, an alarm is generated to stop the critical operation when generation of a period of more than a predetermined value predicted by succeeding critical operation. With such procedures, forecasting for the critical point can be easily predicted upon critical operation to greatly mitigate an operator's burden and improve handling for the operation. (N.H.)

  11. Introduction: Critical Visual Theory

    Directory of Open Access Journals (Sweden)

    Peter Ludes

    2014-03-01

    Full Text Available The studies selected for publication in this special issue on Critical Visual Theory can be divided into three thematic groups: (1 image making as power making, (2 commodification and recanonization, and (3 approaches to critical visual theory. The approaches to critical visual theory adopted by the authors of this issue may be subsumed under the following headings (3.1 critical visual discourse and visual memes in general and Anonymous visual discourse in particular, (3.2 collective memory and gendered gaze, and (3.3 visual capitalism, global north and south.

  12. Dynamic strength of cylindrical fiber-glass shells and basalt plastic shells under multiple explosive loading

    Science.gov (United States)

    Syrunin, M. A.; Fedorenko, A. G.

    2006-08-01

    We have shown experimentally that, for cylindrical shells made of oriented fiberglass platic and basalt plastic there exists a critical level of deformations, at which a structure sustains a given number of explosions from the inside. The magnitude of critical deformation for cylindrical fiberglass shells depends linearly on the logarithm of the number of loads that cause failure. For a given type of fiberglass, there is a limiting level of explosive action, at which the number of loads that do not lead to failure can be sufficiently large (more than ˜ 102). This level is attained under loads, which are an order of magnitude lower than the limiting loads under a single explosive action. Basalt plastic shells can be repeatedly used even at the loads, which cause deformation by ˜ 30-50% lower than the safe value ˜ 3.3.5% at single loading.

  13. Consideration of criticality in a nuclear waste repository

    International Nuclear Information System (INIS)

    Rechard, R.P.; Sanchez, L.C.; Stockman, C.T.; Ramsey, J.L. Jr.; Martell, M.

    1995-01-01

    The preliminary criticality analysis that was done suggests that the possibility of achieving critical conditions cannot be easily ruled out without looking at the geochemical process of assembly or the dynamics of the operation of a critical assembly. The evaluation of a critical assembly requires an integrated, consistent approach that includes evaluating the following: (1) the alteration rates of the layers of the container and spent fuel, (2) the transport of fissile material or neutron absorbers, and (3) the assembly mechanisms that can achieve critical conditions. The above is a non-trivial analysis and preliminary work suggests that with the loading assumed, enough fissile mass will leach from the HEU multi-purpose canisters to support a criticality. In addition, the consequences of an unpressurized Oklo type criticality would be insignificant to the performance of an unsaturated, tuff repository

  14. The role of mechanical loading in ligament tissue engineering.

    Science.gov (United States)

    Benhardt, Hugh A; Cosgriff-Hernandez, Elizabeth M

    2009-12-01

    Tissue-engineered ligaments have received growing interest as a promising alternative for ligament reconstruction when traditional transplants are unavailable or fail. Mechanical stimulation was recently identified as a critical component in engineering load-bearing tissues. It is well established that living tissue responds to altered loads through endogenous changes in cellular behavior, tissue organization, and bulk mechanical properties. Without the appropriate biomechanical cues, new tissue formation lacks the necessary collagenous organization and alignment for sufficient load-bearing capacity. Therefore, tissue engineers utilize mechanical conditioning to guide tissue remodeling and improve the performance of ligament grafts. This review provides a comparative analysis of the response of ligament and tendon fibroblasts to mechanical loading in current bioreactor studies. The differential effect of mechanical stimulation on cellular processes such as protease production, matrix protein synthesis, and cell proliferation is examined in the context of tissue engineering design.

  15. Load Forecasting in Electric Utility Integrated Resource Planning

    Energy Technology Data Exchange (ETDEWEB)

    Carvallo, Juan Pablo [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Larsen, Peter H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sanstad, Alan H [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Goldman, Charles A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-07-19

    Integrated resource planning (IRP) is a process used by many vertically-integrated U.S. electric utilities to determine least-cost/risk supply and demand-side resources that meet government policy objectives and future obligations to customers and, in many cases, shareholders. Forecasts of energy and peak demand are a critical component of the IRP process. There have been few, if any, quantitative studies of IRP long-run (planning horizons of two decades) load forecast performance and its relationship to resource planning and actual procurement decisions. In this paper, we evaluate load forecasting methods, assumptions, and outcomes for 12 Western U.S. utilities by examining and comparing plans filed in the early 2000s against recent plans, up to year 2014. We find a convergence in the methods and data sources used. We also find that forecasts in more recent IRPs generally took account of new information, but that there continued to be a systematic over-estimation of load growth rates during the period studied. We compare planned and procured resource expansion against customer load and year-to-year load growth rates, but do not find a direct relationship. Load sensitivities performed in resource plans do not appear to be related to later procurement strategies even in the presence of large forecast errors. These findings suggest that resource procurement decisions may be driven by other factors than customer load growth. Our results have important implications for the integrated resource planning process, namely that load forecast accuracy may not be as important for resource procurement as is generally believed, that load forecast sensitivities could be used to improve the procurement process, and that management of load uncertainty should be prioritized over more complex forecasting techniques.

  16. ACRR fuel storage racks criticality safety analysis

    International Nuclear Information System (INIS)

    Bodette, D.E.; Naegeli, R.E.

    1997-10-01

    This document presents the criticality safety analysis for a new fuel storage rack to support modification of the Annular Core Research Reactor for production of molybdenum-99 at Sandia National Laboratories, Technical Area V facilities. Criticality calculations with the MCNP code investigated various contingencies for the criticality control parameters. Important contingencies included mix of fuel element types stored, water density due to air bubbles or water level for the over-moderated racks, interaction with existing fuel storage racks and fuel storage holsters in the fuel storage pool, neutron absorption of planned rack design and materials, and criticality changes due to manufacturing tolerances or damage. Some limitations or restrictions on use of the new fuel storage rack for storage operations were developed through the criticality analysis and are required to meet the double contingency requirements of criticality safety. As shown in the analysis, this system will remain subcritical under all credible upset conditions. Administrative controls are necessary for loading, moving, and handling the storage rack as well as for control of operations around it. 21 refs., 16 figs., 4 tabs

  17. Rescuing loading induced bone formation at senescence.

    Directory of Open Access Journals (Sweden)

    Sundar Srinivasan

    2010-09-01

    Full Text Available The increasing incidence of osteoporosis worldwide requires anabolic treatments that are safe, effective, and, critically, inexpensive given the prevailing overburdened health care systems. While vigorous skeletal loading is anabolic and holds promise, deficits in mechanotransduction accrued with age markedly diminish the efficacy of readily complied, exercise-based strategies to combat osteoporosis in the elderly. Our approach to explore and counteract these age-related deficits was guided by cellular signaling patterns across hierarchical scales and by the insight that cell responses initiated during transient, rare events hold potential to exert high-fidelity control over temporally and spatially distant tissue adaptation. Here, we present an agent-based model of real-time Ca(2+/NFAT signaling amongst bone cells that fully described periosteal bone formation induced by a wide variety of loading stimuli in young and aged animals. The model predicted age-related pathway alterations underlying the diminished bone formation at senescence, and hence identified critical deficits that were promising targets for therapy. Based upon model predictions, we implemented an in vivo intervention and show for the first time that supplementing mechanical stimuli with low-dose Cyclosporin A can completely rescue loading induced bone formation in the senescent skeleton. These pre-clinical data provide the rationale to consider this approved pharmaceutical alongside mild physical exercise as an inexpensive, yet potent therapy to augment bone mass in the elderly. Our analyses suggested that real-time cellular signaling strongly influences downstream bone adaptation to mechanical stimuli, and quantification of these otherwise inaccessible, transient events in silico yielded a novel intervention with clinical potential.

  18. Validity of bioluminescence measurements for noninvasive in vivo imaging of tumor load in small animals

    NARCIS (Netherlands)

    Klerk, Clara P. W.; Overmeer, Renée M.; Niers, Tatjana M. H.; Versteeg, Henri H.; Richel, Dick J.; Buckle, Tessa; van Noorden, Cornelis J. F.; van Tellingen, Olaf

    2007-01-01

    A relatively new strategy to longitudinally monitor tumor load in intact animals and the effects of therapy is noninvasive bioluminescence imaging (BLI). The validity of BLI for quantitative assessment of tumor load in small animals is critically evaluated in the present review. Cancer cells are

  19. How does cognitive load influence speech perception? An encoding hypothesis.

    Science.gov (United States)

    Mitterer, Holger; Mattys, Sven L

    2017-01-01

    Two experiments investigated the conditions under which cognitive load exerts an effect on the acuity of speech perception. These experiments extend earlier research by using a different speech perception task (four-interval oddity task) and by implementing cognitive load through a task often thought to be modular, namely, face processing. In the cognitive-load conditions, participants were required to remember two faces presented before the speech stimuli. In Experiment 1, performance in the speech-perception task under cognitive load was not impaired in comparison to a no-load baseline condition. In Experiment 2, we modified the load condition minimally such that it required encoding of the two faces simultaneously with the speech stimuli. As a reference condition, we also used a visual search task that in earlier experiments had led to poorer speech perception. Both concurrent tasks led to decrements in the speech task. The results suggest that speech perception is affected even by loads thought to be processed modularly, and that, critically, encoding in working memory might be the locus of interference.

  20. Alaska Village Electric Load Calculator

    Energy Technology Data Exchange (ETDEWEB)

    Devine, M.; Baring-Gould, E. I.

    2004-10-01

    As part of designing a village electric power system, the present and future electric loads must be defined, including both seasonal and daily usage patterns. However, in many cases, detailed electric load information is not readily available. NREL developed the Alaska Village Electric Load Calculator to help estimate the electricity requirements in a village given basic information about the types of facilities located within the community. The purpose of this report is to explain how the load calculator was developed and to provide instructions on its use so that organizations can then use this model to calculate expected electrical energy usage.

  1. Load forecasting for supermarket refrigeration

    DEFF Research Database (Denmark)

    Bacher, Peder; Madsen, Henrik; Aalborg Nielsen, Henrik

    This report presents a study of models for forecasting the load for supermarket refrigeration. The data used for building the forecasting models consists of load measurements, local climate measurements and weather forecasts. The load measurements are from a supermarket located in a village...... in Denmark. The load for refrigeration is the sum of all cabinets in the supermarket, both low and medium temperature cabinets, and spans a period of one year. As input to the forecasting models the ambient temperature observed near the supermarket together with weather forecasts are used. Every hour...

  2. Empathy and the Critic

    Science.gov (United States)

    Jurecic, Ann

    2011-01-01

    "Empathy" is a much-discussed term in the humanities these days. While some critics value it and argue that literature desirably promotes it, other critics worry that appeals to this emotion will neglect important matters of social context. In the literature classroom, the best approach is to take time to consider how texts complicate the impulse…

  3. Critical Literacy: Foundational Notes

    Science.gov (United States)

    Luke, Allan

    2012-01-01

    The term "critical literacy" refers to use of the technologies of print and other media of communication to analyze, critique, and transform the norms, rule systems, and practices governing the social fields of everyday life (A. Luke, 2004). Since Freire's (1970) educational projects in Brazil, approaches to critical literacy have been…

  4. Criticality alarm device

    International Nuclear Information System (INIS)

    Kasai, Kenji.

    1994-01-01

    The device of the present invention is utilized, for example, to a reprocessing facility for storing and processing nuclear fuels and measures and controls the nuclear fuel assembly system so as not to exceed criticality. That is, a conventional criticality alarm device applies a predetermined processing to neutron fluxes generated from a nuclear fuel assembly system containing nuclear fuels and outputs an alarm. The device of the present invention comprises (1) a neutron flux supply source for increasing and decreasing neutron fluxes periodically and supplying them to nuclear fuel assemblies, (2) a detector for detecting neutron fluxes in the nuclear fuel assemblies, (3) a critical state judging section for judging the critical state of the nuclear fuel assemblies based on the periodically changing signals obtained from the detector (2) and (4) an alarm section for outputting criticality alarms depending on the result of the judgement. The device of the present invention can accurately recognize the critical state of the nuclear fuel assembly system and can forecast reaching of the nuclear fuel assembly to criticality or prompt neutron critical state. (I.S.)

  5. Critical Response Protocol

    Science.gov (United States)

    Ellingson, Charlene; Roehrig, Gillian; Bakkum, Kris; Dubinsky, Janet M.

    2016-01-01

    This article introduces the Critical Response Protocol (CRP), an arts-based technique that engages students in equitable critical discourse and aligns with the "Next Generation Science Standards" vision for providing students opportunities for language learning while advancing science learning (NGSS Lead States 2013). CRP helps teachers…

  6. Critical Chain Exercises

    Science.gov (United States)

    Doyle, John Kevin

    2010-01-01

    Critical Chains project management focuses on holding buffers at the project level vs. task level, and managing buffers as a project resource. A number of studies have shown that Critical Chain project management can significantly improve organizational schedule fidelity (i.e., improve the proportion of projects delivered on time) and reduce…

  7. Nuclear criticality safety guide

    International Nuclear Information System (INIS)

    Ro, Seong Ki; Shin, Hee Seong; Park, Seong Won; Shin, Young Joon.

    1997-06-01

    Nuclear criticality safety guide was described for handling, transportation and storage of nuclear fissile materials in this report. The major part of the report was excerpted frp, TID-7016(revision 2) and nuclear criticality safety written by Knief. (author). 16 tabs., 44 figs., 5 refs

  8. Critical Utopian Action Research

    DEFF Research Database (Denmark)

    Nielsen, Birger Steen; Nielsen, Kurt Aagaard

    2016-01-01

    The specific concept of critical utopian action research is presented and discussed, as to its origin, use and potentials. The inspiration from Robert Jungk and his future creating workshops is elaborated.......The specific concept of critical utopian action research is presented and discussed, as to its origin, use and potentials. The inspiration from Robert Jungk and his future creating workshops is elaborated....

  9. Critical Habitat :: NOAA Fisheries

    Science.gov (United States)

    occupied by the species at the time of listing, if they contain physical or biological features essential essential for conservation. Critical Habitat Maps NOTE: The critical habitat maps provided here are for Data Leatherback Turtle (U.S. West Coast) » Biological Report » Economic Report 2012 77 FR 4170 Go to

  10. Self organized criticality

    International Nuclear Information System (INIS)

    Creutz, M.

    1993-03-01

    Self organized criticality refers to the tendency of highly dissipative systems to drive themselves to a critical state. This has been proposed to explain why observed physics often displays a wide disparity of length and time scales. The phenomenon can be studied in simple cellular automaton models

  11. Critical Pedagogy and Faith

    Science.gov (United States)

    Neumann, Jacob W.

    2011-01-01

    Critical pedagogy has often been linked in the literature to faith traditions such as liberation theology, usually with the intent of improving or redirecting it. While recognizing and drawing from those previous linkages, Jacob Neumann goes further in this essay and develops the thesis that critical pedagogy can not just benefit from a connection…

  12. Critical parameters for ammonia

    International Nuclear Information System (INIS)

    Sato, M.; Masui, G.; Uematsu, M.

    2005-01-01

    (p, ρ, T) measurements and visual observations of the meniscus for ammonia were carried out carefully in the critical region over the range of temperatures: -1 K (T - T c ) 0.04 K, and of densities: -19 kg . m -3 (ρ - ρ c ) 19 kg . m -3 by a metal-bellows volumometer with an optical cell. Vapor pressures were also measured at T = (310, 350, and 400) K. The critical parameters of T c and ρ c were determined based on the results of observation of the critical opalescence. The critical pressure p c was determined from the present measurements at T c on the vapor pressure curve. Comparisons of the critical parameters with values given in the literature are presented

  13. Critical parameters for ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Sato, M. [Center for Mechanical Engineering and Applied Mechanics, Keio University, Hiyoshi 3-14-1, Kohoku-ku, Yokohama 223-8522 (Japan); Masui, G. [Center for Mechanical Engineering and Applied Mechanics, Keio University, Hiyoshi 3-14-1, Kohoku-ku, Yokohama 223-8522 (Japan); Uematsu, M. [Center for Mechanical Engineering and Applied Mechanics, Keio University, Hiyoshi 3-14-1, Kohoku-ku, Yokohama 223-8522 (Japan)]. E-mail: uematsu@mech.keio.ac.jp

    2005-09-15

    (p, {rho}, T) measurements and visual observations of the meniscus for ammonia were carried out carefully in the critical region over the range of temperatures: -1 K (T - T {sub c}) 0.04 K, and of densities: -19 kg . m{sup -3} ({rho} - {rho} {sub c}) 19 kg . m{sup -3} by a metal-bellows volumometer with an optical cell. Vapor pressures were also measured at T = (310, 350, and 400) K. The critical parameters of T {sub c} and {rho} {sub c} were determined based on the results of observation of the critical opalescence. The critical pressure p {sub c} was determined from the present measurements at T {sub c} on the vapor pressure curve. Comparisons of the critical parameters with values given in the literature are presented.

  14. Taking Critical Ontology Seriously

    DEFF Research Database (Denmark)

    Wigger, Angela; Horn, Laura

    2017-01-01

    To be ‘critical’ has become fashionable among social scientists in various disciplines. Only a few decades ago, the prefix ‘critical’ was almost automatically associated with Western Marxism and in particular the Frankfurt School. Today, the term critical is no longer limited to a single...... theoretical approach, but pertains to a vast range of approaches, including feminist, reflexive, postcolonial, postmodern or poststructuralist studies, and studies committed to a post-positivist epistemology more generally. But what does critical social science actually mean? Which implications does critical...... a primer on a few core dimensions of critical social science and its central premises. It discusses first what critical social science is not, and clarifies key differences between what is commonly referred to as ‘mainstream’ and ‘critical’ social science perspectives. It addresses the role of normative...

  15. Probabilistic Load Models for Simulating the Impact of Load Management

    DEFF Research Database (Denmark)

    Chen, Peiyuan; Bak-Jensen, Birgitte; Chen, Zhe

    2009-01-01

    . It is concluded that the AR(12) model is favored with limited measurement data and that the joint-normal model may provide better results with a large data set. Both models can be applied in general to model load time series and used in time-sequential simulation of distribution system planning.......This paper analyzes a distribution system load time series through autocorrelation coefficient, power spectral density, probabilistic distribution and quantile value. Two probabilistic load models, i.e. the joint-normal model and the autoregressive model of order 12 (AR(12)), are proposed...... to simulate the impact of load management. The joint-normal model is superior in modeling the tail region of the hourly load distribution and implementing the change of hourly standard deviation. Whereas the AR(12) model requires much less parameter and is superior in modeling the autocorrelation...

  16. High thermal load structure

    International Nuclear Information System (INIS)

    Tsujimura, Seiichi; Toyota, Masahiko.

    1995-01-01

    A highly thermal load structure applied to a plasma-opposed equipment of a thermonuclear device comprises heat resistant protection tiles and a cooling tube disposed in the protection tiles. As the protection tiles, a carbon/carbon composite material is used. The carbon/carbon composite material on the heat receiving surface comprises carbon fibers disposed in one direction (one dimensionally) arranged from the heat receiving surface toward the cooling tube. The carbon/carbon composite material on the side opposite to the heat receiving surface comprises carbon fibers arranged two-dimensionally in the direction perpendicular to the longitudinal direction of the cooling tube. Then, the cooling tube is interposed between the one-dimensional carbon/carbon composite material and the two-dimensional carbon/carbon composite material, and they are joined with each other by vacuum brazing. This can improve heat removing performance. In addition, thermal stresses at the joined portion is reduced. Further, electromagnetic force generated in the thermonuclear device is reduced. (I.N.)

  17. High thermal load structure

    Energy Technology Data Exchange (ETDEWEB)

    Tsujimura, Seiichi; Toyota, Masahiko

    1995-06-16

    A highly thermal load structure applied to a plasma-opposed equipment of a thermonuclear device comprises heat resistant protection tiles and a cooling tube disposed in the protection tiles. As the protection tiles, a carbon/carbon composite material is used. The carbon/carbon composite material on the heat receiving surface comprises carbon fibers disposed in one direction (one dimensionally) arranged from the heat receiving surface toward the cooling tube. The carbon/carbon composite material on the side opposite to the heat receiving surface comprises carbon fibers arranged two-dimensionally in the direction perpendicular to the longitudinal direction of the cooling tube. Then, the cooling tube is interposed between the one-dimensional carbon/carbon composite material and the two-dimensional carbon/carbon composite material, and they are joined with each other by vacuum brazing. This can improve heat removing performance. In addition, thermal stresses at the joined portion is reduced. Further, electromagnetic force generated in the thermonuclear device is reduced. (I.N.).

  18. Control of criticality; Kawalan kegentingan

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1988-12-31

    The chapter briefly discussed the following subjects: basic and the principle of criticality, natural uranium, neutron utilization, criticality data for systems, criticality accidents, criticality control i.e. mass, volume and geometry control .

  19. The Possibility of Film Criticism.

    Science.gov (United States)

    Poague, Leland; Cadbury, William

    1989-01-01

    Examines the role of critical language in film criticism. Compares and contrasts Monroe Beardsley's philosophy on film aesthetics with the New Criticism. Outlines some of the contributions Beardsley has made to the study of film criticism. (KM)

  20. Effects of noise and task loading on a communication task loading on a communication task

    Science.gov (United States)

    Orrell, Dean H., II

    Previous research had shown the effect of noise on a single communication task. This research has been criticized as not being representative of a real world situation since subjects allocated all of their attention to only one task. In the present study, the effect of adding a loading task to a standard noise-communication paradigm was investigated. Subjects performed both a communication task (Modified Rhyme Test; House et al. 1965) and a short term memory task (Sternberg, 1969) in simulated levels of aircraft noise (95, 105 and 115 dB overall sound pressure level (OASPL)). Task loading was varied with Sternberg's task by requiring subjects to memorize one, four, or six alphanumeric characters. Simulated aircraft noise was varied between levels of 95, 105 and 115 dB OASPL using a pink noise source. Results show that the addition of Sternberg's task and little effect on the intelligibility of the communication task while response time for the communication task increased.

  1. Effects of stressor characteristics on early warning signs of critical transitions and "critical coupling" in complex dynamical systems.

    Science.gov (United States)

    Blume, Steffen O P; Sansavini, Giovanni

    2017-12-01

    Complex dynamical systems face abrupt transitions into unstable and catastrophic regimes. These critical transitions are triggered by gradual modifications in stressors, which push the dynamical system towards unstable regimes. Bifurcation analysis can characterize such critical thresholds, beyond which systems become unstable. Moreover, the stochasticity of the external stressors causes small-scale fluctuations in the system response. In some systems, the decomposition of these signal fluctuations into precursor signals can reveal early warning signs prior to the critical transition. Here, we present a dynamical analysis of a power system subjected to an increasing load level and small-scale stochastic load perturbations. We show that the auto- and cross-correlations of bus voltage magnitudes increase, leading up to a Hopf bifurcation point, and further grow until the system collapses. This evidences a gradual transition into a state of "critical coupling," which is complementary to the established concept of "critical slowing down." Furthermore, we analyze the effects of the type of load perturbation and load characteristics on early warning signs and find that gradient changes in the autocorrelation provide early warning signs of the imminent critical transition under white-noise but not for auto-correlated load perturbations. Furthermore, the cross-correlation between all voltage magnitude pairs generally increases prior to and beyond the Hopf bifurcation point, indicating "critical coupling," but cannot provide early warning indications. Finally, we show that the established early warning indicators are oblivious to limit-induced bifurcations and, in the case of the power system model considered here, only react to an approaching Hopf bifurcation.

  2. 2011 Annual Criticality Safety Program Performance Summary

    Energy Technology Data Exchange (ETDEWEB)

    Andrea Hoffman

    2011-12-01

    TSR limits fuel plate bundles to 1085 grams U-235, which is the maximum loading of an ATR fuel element. The overloaded fuel plate bundle contained 1097 grams U-235 and was assembled under an 1100 gram U-235 limit in 1982. In 2003, the limit was reduced to 1085 grams citing a new criticality safety evaluation for ATR fuel elements. The fuel plate bundle inventories were not checked for compliance prior to implementing the reduced limit. A subsequent review of the NMIS inventory did not identify further violations. Requirements Management - The INL Criticality Safety program is organized and well documented. The source requirements for the INL Criticality Safety Program are from 10 CFR 830.204, DOE Order 420.1B, Chapter III, 'Nuclear Criticality Safety,' ANSI/ANS 8-series Industry Standards, and DOE Standards. These source requirements are documented in LRD-18001, 'INL Criticality Safety Program Requirements Manual.' The majority of the criticality safety source requirements are contained in DOE Order 420.1B because it invokes all of the ANSI/ANS 8-Series Standards. DOE Order 420.1B also invokes several DOE Standards, including DOE-STD-3007, 'Guidelines for Preparing Criticality Safety Evaluations at Department of Energy Non-Reactor Nuclear Facilities.' DOE Order 420.1B contains requirements for DOE 'Heads of Field Elements' to approve the criticality safety program and specific elements of the program, namely, the qualification of criticality staff and the method for preparing criticality safety evaluations. This was accomplished by the approval of SAR-400, 'INL Standardized Nuclear Safety Basis Manual,' Chapter 6, 'Prevention of Inadvertent Criticality.' Chapter 6 of SAR-400 contains sufficient detail and/or reference to the specific DOE and contractor documents that adequately describe the INL Criticality Safety Program per the elements specified in DOE Order 420.1B. The Safety Evaluation Report for SAR-400

  3. Laterally Loaded Nail-Plates

    DEFF Research Database (Denmark)

    Nielsen, Jacob; Rathkjen, Arne

    Load-displacement curves from about 200 short-term and laterally loaded nail-plate joints are analysed. The nail-plates are from Gang-Nail Systems, type GNA 20 S. The test specimens and the measuring systems are described. The tests are divided into 32 different series. The influence of the number...

  4. Fatigue Reliability under Random Loads

    DEFF Research Database (Denmark)

    Talreja, R.

    1979-01-01

    We consider the problem of estimating the probability of survival (non-failure) and the probability of safe operation (strength greater than a limiting value) of structures subjected to random loads. These probabilities are formulated in terms of the probability distributions of the loads...... propagation stage. The consequences of this behaviour on the fatigue reliability are discussed....

  5. Loading Conditions and Longitudinal Strength

    DEFF Research Database (Denmark)

    Sørensen, Herman

    1995-01-01

    Methods for the calculation of the lightweight of the ship.Loading conditions satisfying draught, trim and intact stability requirements and analysis of the corresponding stillwater longitudinal strength.......Methods for the calculation of the lightweight of the ship.Loading conditions satisfying draught, trim and intact stability requirements and analysis of the corresponding stillwater longitudinal strength....

  6. Inexpensive Bolt-Load Gage

    Science.gov (United States)

    Long, M. J.

    1983-01-01

    "Built-in" gage determines whether large bolt or stud has been torqued to desired load and provides for continuous inspection to ensure proper load is being maintained. Gage detects longitudinal stress/strain bolt; requires no electronic or sonic test equipment.

  7. Nuclear fuel rod loading apparatus

    International Nuclear Information System (INIS)

    King, H.B.

    1981-01-01

    A nuclear fuel loading apparatus, incorporating a microprocessor control unit, is described which automatically loads nuclear fuel pellets into dual fuel rods with a minimum of manual involvement and in a manner and sequence to ensure quality control and accuracy. (U.K.)

  8. The french criticality handbook

    International Nuclear Information System (INIS)

    Maubert, L.; Puit, J.C.

    1987-01-01

    The french criticality handbook, published in 1978 by the ''Commissariat a l'Energie Atomique'', is presented with the main targets aimed by the writer and the main choices taken relating to fissile mediums, reflection conditions, dilution curves. The validation of the critical values is presented as one of the most important aspects of this handbook which is mainly intended, in the mind of the author, to specialists well advertised in the field of criticality. The complements which have been introduced since 1978 and those which are foreseen in a near future are also detailed. (author)

  9. Frustration and quantum criticality

    Science.gov (United States)

    Vojta, Matthias

    2018-06-01

    This review article is devoted to the interplay between frustrated magnetism and quantum critical phenomena, covering both theoretical concepts and ideas as well as recent experimental developments in correlated-electron materials. The first part deals with local-moment magnetism in Mott insulators and the second part with frustration in metallic systems. In both cases, frustration can either induce exotic phases accompanied by exotic quantum critical points or lead to conventional ordering with unconventional crossover phenomena. In addition, the competition of multiple phases inherent to frustrated systems can lead to multi-criticality.

  10. Frustration and quantum criticality.

    Science.gov (United States)

    Vojta, Matthias

    2018-03-15

    This review article is devoted to the interplay between frustrated magnetism and quantum critical phenomena, covering both theoretical concepts and ideas as well as recent experimental developments in correlated-electron materials. The first part deals with local-moment magnetism in Mott insulators and the second part with frustration in metallic systems. In both cases, frustration can either induce exotic phases accompanied by exotic quantum critical points or lead to conventional ordering with unconventional crossover phenomena. In addition, the competition of multiple phases inherent to frustrated systems can lead to multi-criticality. © 2018 IOP Publishing Ltd.

  11. Minimum critical mass systems

    International Nuclear Information System (INIS)

    Dam, H. van; Leege, P.F.A. de

    1987-01-01

    An analysis is presented of thermal systems with minimum critical mass, based on the use of materials with optimum neutron moderating and reflecting properties. The optimum fissile material distributions in the systems are obtained by calculations with standard computer codes, extended with a routine for flat fuel importance search. It is shown that in the minimum critical mass configuration a considerable part of the fuel is positioned in the reflector region. For 239 Pu a minimum critical mass of 87 g is found, which is the lowest value reported hitherto. (author)

  12. PREPP criticality control

    International Nuclear Information System (INIS)

    Cargo, C.H.; Becker, G.K.; Berglund, G.R.; O'Connor, N.J.

    1989-03-01

    There is a general lack of data available with regards to criticality control in the use of incineration for full scale processing of TRU waste. In addition to the new analytical tools, such as PRA, are only now starting to be applied to criticality control. These factors have made the development of the PREPP Criticality Control Plan somewhat unique. It is hoped that the PREPP experiences gained in these efforts will provide new insight which will be useful to future facilities processing waste material containing fissile material. 1 fig

  13. Umbilical Cable Recovery Load Analysis

    Institute of Scientific and Technical Information of China (English)

    YAN Shu-wang; JIA Zhao-lin; FENG Xiao-wei; LI Shi-tao

    2013-01-01

    Umbilical cable is a kind of integrated subsea cable widely used in the exploration and exploitation of oil and gas field.The severe ocean environment makes great challenges to umbilical maintenance and repair work.Damaged umbilical is usually recovered for the regular operation of the offshore production system.Analysis on cables in essence is a two-point boundary problem.The tension load at the mudline must be known first,and then the recovery load and recovery angle on the vessel can be solved by use of catenary equation.The recovery analysis also involves umbilicalsoil interaction and becomes more complicated.Calculation methods for recovery load of the exposed and buried umbilical are established and the relationship between the position of touch down point and the recovery load as well as the recovery angle and recovery load are analyzed.The analysis results provide a theoretical reference for offshore on-deck operation.

  14. Scaling structure loads for SMA

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong Won; Song, Jeong Guk; Jeon, Sang Ho; Lim, Hak Kyu; Lee, Kwang Nam [KEPCO ENC, Yongin (Korea, Republic of)

    2012-10-15

    When the Seismic Margin Analysis(SMA) is conducted, the new structural load generation with Seismic Margin Earthquake(SME) is the time consuming work. For the convenience, EPRI NP 6041 suggests the scaling of the structure load. The report recommend that the fixed base(rock foundation) structure designed using either constant modal damping or modal damping ratios developed for a single material damping. For these cases, the SME loads can easily and accurately be calculated by scaling the spectral accelerations of the individual modes for the new SME response spectra. EPRI NP 6041 provides two simple methodologies for the scaling structure seismic loads which are the dominant frequency scaling methodology and the mode by mode scaling methodology. Scaling of the existing analysis to develop SME loads is much easier and more efficient than performing a new analysis. This paper is intended to compare the calculating results of two different methodologies.

  15. Scaling structure loads for SMA

    International Nuclear Information System (INIS)

    Lee, Dong Won; Song, Jeong Guk; Jeon, Sang Ho; Lim, Hak Kyu; Lee, Kwang Nam

    2012-01-01

    When the Seismic Margin Analysis(SMA) is conducted, the new structural load generation with Seismic Margin Earthquake(SME) is the time consuming work. For the convenience, EPRI NP 6041 suggests the scaling of the structure load. The report recommend that the fixed base(rock foundation) structure designed using either constant modal damping or modal damping ratios developed for a single material damping. For these cases, the SME loads can easily and accurately be calculated by scaling the spectral accelerations of the individual modes for the new SME response spectra. EPRI NP 6041 provides two simple methodologies for the scaling structure seismic loads which are the dominant frequency scaling methodology and the mode by mode scaling methodology. Scaling of the existing analysis to develop SME loads is much easier and more efficient than performing a new analysis. This paper is intended to compare the calculating results of two different methodologies

  16. Allowable heat load on the edge of the ITER first wall panel beryllium flat tiles

    Directory of Open Access Journals (Sweden)

    R. Mitteau

    2017-08-01

    Full Text Available Plasma facing components are usually qualified to a given heat load density applied at the top face of the armour tiles with normal incidence angle. When employed in tokamak fusion machines, heat loading on the tile sides is possible due to optimised shaping, that doesn't provide edge shadowing for all design situations. An edge heat load may occur both at the tile and component scales. The edge load needs to be controlled and quantified. The adequate control of edge heat loads is especially critical for water cooled components that uses armour tiles which are bonded to the heat sink, for ensuring the long-term integrity of the tile bonding. An edge heat load allowance criterion of 10% of the top heat load is proposed. The 10% criterion is supported by experimental heat flux tests.

  17. Retrospective Analysis of Inflight Exercise Loading and Physiological Outcomes

    Science.gov (United States)

    Ploutz-Snyder, L. L.; Buxton, R. E.; De Witt, J. K.; Guilliams, M. E.; Hanson, A. M.; Peters, B. T.; Pandorf, M. M. Scott; Sibonga, J. D.

    2014-01-01

    Astronauts perform exercise throughout their missions to counter the health declines that occur as a result of long-term exposure to weightlessness. Although all astronauts perform exercise during their missions, the specific prescriptions, and thus the mechanical loading, differs among individuals. For example, inflight ground reaction force data indicate that subject-specific differences exist in foot forces created when exercising on the second-generation treadmill (T2) [1]. The current exercise devices allow astronauts to complete prescriptions at higher intensities, resulting in greater benefits with increased efficiency. Although physiological outcomes have improved, the specific factors related to the increased benefits are unknown. In-flight exercise hardware collect data that allows for exploratory analyses to determine if specific performance factors relate to physiological outcomes. These analyses are vital for understanding which components of exercise are most critical for optimal human health and performance. The relationship between exercise performance variables and physiological changes during flight has yet to be fully investigated. Identifying the critical performance variables that relate to improved physiological outcomes is vital for creating current and future exercise prescriptions to optimize astronaut health. The specific aims of this project are: 1) To quantify the exercise-related mechanical loading experienced by crewmembers on T2 and ARED during their mission on ISS; 2) To explore relationships between exercise loading variables, bone, and muscle health changes during the mission; 3) To determine if specific mechanical loading variables are more critical than others in protecting physiology; 4) To develop methodology for operational use in monitoring accumulated training loads during crew exercise programs. This retrospective analysis, which is currently in progress, is being conducted using data from astronauts that have flown long

  18. Designated Critical Habitat

    Data.gov (United States)

    Kansas Data Access and Support Center — Critical habitats include those areas documented as currently supporting self-sustaining populations of any threatened or endangered species of wildlife as well as...

  19. Coastal Critical Habitat Designations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Endangered Species Act (ESA) requires the Federal government to designate critical habitat, areas of habitat essential to the species' conservation, for ESA...

  20. Silencing criticism in Mexico

    Directory of Open Access Journals (Sweden)

    Ximena Suárez

    2017-10-01

    Full Text Available Journalists and human rights defenders in Mexico are being attacked in an attempt to silence their criticism. Many are forced to flee or risk being assassinated. The consequences are both personal and of wider social significance.

  1. Smalltooth Sawfish Critical Habitat

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data represent the critical habitat for smalltooth sawfish (Pristis pectinatat) as designated by 74 FR 45353, September 2, 2009, Rules and Regulations.

  2. Critical Robotic Lunar Missions

    Science.gov (United States)

    Plescia, J. B.

    2018-04-01

    Perhaps the most critical missions to understanding lunar history are in situ dating and network missions. These would constrain the volcanic and thermal history and interior structure. These data would better constrain lunar evolution models.

  3. Critical-point nuclei

    International Nuclear Information System (INIS)

    Clark, R.M.

    2004-01-01

    It has been suggested that a change of nuclear shape may be described in terms of a phase transition and that specific nuclei may lie close to the critical point of the transition. Analytical descriptions of such critical-point nuclei have been introduced recently and they are described briefly. The results of extensive searches for possible examples of critical-point behavior are presented. Alternative pictures, such as describing bands in the candidate nuclei using simple ΔK = 0 and ΔK = 2 rotational-coupling models, are discussed, and the limitations of the different approaches highlighted. A possible critical-point description of the transition from a vibrational to rotational pairing phase is suggested

  4. Probabilistic Criticality Consequence Evaluation

    International Nuclear Information System (INIS)

    P. Gottlieb; J.W. Davis; J.R. Massari

    1996-01-01

    This analysis is prepared by the Mined Geologic Disposal System (MGDS) Waste Package Development (WPD) department with the objective of providing a comprehensive, conservative estimate of the consequences of the criticality which could possibly occur as the result of commercial spent nuclear fuel emplaced in the underground repository at Yucca Mountain. The consequences of criticality are measured principally in terms of the resulting changes in radionuclide inventory as a function of the power level and duration of the criticality. The purpose of this analysis is to extend the prior estimates of increased radionuclide inventory (Refs. 5.52 and 5.54), for both internal and external criticality. This analysis, and similar estimates and refinements to be completed before the end of fiscal year 1997, will be provided as input to Total System Performance Assessment-Viability Assessment (TSPA-VA) to demonstrate compliance with the repository performance objectives

  5. Right Whale Critical Habitat

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data represent the critical habitat for Right Whale as designated by Federal Register Vol. 59, No. 28805, May 19, 1993, Rules and Regulations.

  6. Johnsons Seagrass Critical Habitat

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data represent the critical habitat for Johnson's Seagrass as designated by Federal Register Vol. 65, No. 66, Wednesday, April 5, 2000, Rules and Regulations.

  7. Green Turtle Critical Habitat

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data represent the critical habitat for green turtle as designated by Federal Register Vol. 63, No. 46701, September 2, 1998, Rules and Regulations.

  8. Neutrophils in critical illness.

    Science.gov (United States)

    McDonald, Braedon

    2018-03-01

    During critical illness, dramatic alterations in neutrophil biology are observed including abnormalities of granulopoeisis and lifespan, cell trafficking and antimicrobial effector functions. As a result, neutrophils transition from powerful antimicrobial protectors into dangerous mediators of tissue injury and organ dysfunction. In this article, the role of neutrophils in the pathogenesis of critical illness (sepsis, trauma, burns and others) will be explored, including pathological changes to neutrophil function during critical illness and the utility of monitoring aspects of the neutrophil phenotype as biomarkers for diagnosis and prognostication. Lastly, we review findings from clinical trials of therapies that target the harmful effects of neutrophils, providing a bench-to-bedside perspective on neutrophils in critical illness.

  9. Recovery Act. Advanced Load Identification and Management for Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yi [Eaton Corporation, Menomonee Falls, WI (United States); Casey, Patrick [Eaton Corporation, Menomonee Falls, WI (United States); Du, Liang [Eaton Corporation, Menomonee Falls, WI (United States); He, Dawei [Eaton Corporation, Menomonee Falls, WI (United States)

    2014-02-12

    In response to the U.S. Department of Energy (DoE)’s goal of achieving market ready, net-zero energy residential and commercial buildings by 2020 and 2025, Eaton partnered with the Department of Energy’s National Renewable Energy Laboratory (NREL) and Georgia Institute of Technology to develop an intelligent load identification and management technology enabled by a novel “smart power strip” to provide critical intelligence and information to improve the capability and functionality of building load analysis and building power management systems. Buildings account for 41% of the energy consumption in the United States, significantly more than either transportation or industrial. Within the building sector, plug loads account for a significant portion of energy consumption. Plug load consumes 15-20% of building energy on average. As building managers implement aggressive energy conservation measures, the proportion of plug load energy can increase to as much as 50% of building energy leaving plug loads as the largest remaining single source of energy consumption. This project focused on addressing plug-in load control and management to further improve building energy efficiency accomplished through effective load identification. The execution of the project falls into the following three major aspects; An intelligent load modeling, identification and prediction technology was developed to automatically determine the type, energy consumption, power quality, operation status and performance status of plug-in loads, using electric waveforms at a power outlet level. This project demonstrated the effectiveness of the developed technology through a large set of plug-in loads measurements and testing; A novel “Smart Power Strip (SPS) / Receptacle” prototype was developed to act as a vehicle to demonstrate the feasibility of load identification technology as a low-cost, embedded solution; and Market environment for plug-in load control and management solutions

  10. Unconventional Quantum Critical Points

    OpenAIRE

    Xu, Cenke

    2012-01-01

    In this paper we review the theory of unconventional quantum critical points that are beyond the Landau's paradigm. Three types of unconventional quantum critical points will be discussed: (1). The transition between topological order and semiclassical spin ordered phase; (2). The transition between topological order and valence bond solid phase; (3). The direct second order transition between different competing orders. We focus on the field theory and universality class of these unconventio...

  11. Scale of Critical Thinking

    OpenAIRE

    Semerci, Nuriye

    2000-01-01

    The main purpose of this study is to develop the scale for critical thinking. The Scale of Critical Thinking was applied to 200 student. In this scale, there are total 55 items, four of which are negative and 51 of which are positive. The KMO (Kaiser-Meyer-Olkin) value is 0.75, the Bartlett test value is 7145.41, and the Cronbach Alpha value is 0.90.

  12. Cognitive Load Theory: How Many Types of Load Does It Really Need?

    Science.gov (United States)

    Kalyuga, Slava

    2011-01-01

    Cognitive load theory has been traditionally described as involving three separate and additive types of load. Germane load is considered as a learning-relevant load complementing extraneous and intrinsic load. This article argues that, in its traditional treatment, germane load is essentially indistinguishable from intrinsic load, and therefore…

  13. Assessment of the transportation route of oversize and excessive loads in relation to the load-bearing capacity of existing bridges

    Science.gov (United States)

    Doležel, Jiří; Novák, Drahomír; Petrů, Jan

    2017-09-01

    Transportation routes of oversize and excessive loads are currently planned in relation to ensure the transit of a vehicle through critical points on the road. Critical points are level-intersection of roads, bridges etc. This article presents a comprehensive procedure to determine a reliability and a load-bearing capacity level of the existing bridges on highways and roads using the advanced methods of reliability analysis based on simulation techniques of Monte Carlo type in combination with nonlinear finite element method analysis. The safety index is considered as a main criterion of the reliability level of the existing construction structures and the index is described in current structural design standards, e.g. ISO and Eurocode. An example of a single-span slab bridge made of precast prestressed concrete girders of the 60 year current time and its load bearing capacity is set for the ultimate limit state and serviceability limit state. The structure’s design load capacity was estimated by the full probability nonlinear MKP analysis using a simulation technique Latin Hypercube Sampling (LHS). Load-bearing capacity values based on a fully probabilistic analysis are compared with the load-bearing capacity levels which were estimated by deterministic methods of a critical section of the most loaded girders.

  14. Furthering critical institutionalism

    Directory of Open Access Journals (Sweden)

    Frances Dalton Cleaver

    2015-03-01

    Full Text Available This special issue furthers the study of natural resource management from a critical institutional perspective. Critical institutionalism (CI is a contemporary body of thought that explores how institutions dynamically mediate relationships between people, natural resources and society. It focuses on the complexity of institutions entwined in everyday social life, their historical formation, the interplay between formal and informal, traditional and modern arrangements, and the power relations that animate them. In such perspectives a social justice lens is often used to scrutinise the outcomes of institutional processes. We argue here that critical institutional approaches have potentially much to offer commons scholarship, particularly through the explanatory power of the concept of bricolage for better understanding institutional change.  Critical institutional approaches, gathering momentum over the past 15 years or so, have excited considerable interest but the insights generated from different disciplinary perspectives remain insufficiently synthesised. Analyses emphasising complexity can be relatively illegible to policy-makers, a fact which lessens their reach. This special issue therefore aims to synthesise critical institutional ideas and so to lay the foundation for moving beyond the emergent stage to make meaningful academic and policy impact. In bringing together papers here we define and synthesise key themes of critical institutionalism, outline the concept of institutional bricolage and identity some key challenges facing this school of thought.

  15. The Critical Bricolage

    Directory of Open Access Journals (Sweden)

    Kim McMillan

    2015-10-01

    Full Text Available Change in health care has become rapid and continuous. Much decision-making processes guiding change management are derived from organizational literature which is heavily reflective of managerial perspectives. These perspectives represent and aim to serve only a small subgroup of organizational members. However, change is complex, fragile, and has higher rates of success and sustainability when change management strategies reflect a multitude of organizational voices. There is a dearth of literature exploring the intersect between organizational and nursing discourses on the subject of rapid and continuous change in health care. Multitheoretical, multimethodological, and multidisciplinary informed approaches to methodological decision making are needed to link organizational and nursing discourses in ways that will offer alternative perspectives on the subject of change. Furthermore, critically guided multitheoretical, multimethodological, and multidisciplinary methodologies are timely and important in organizational research. Critically guided research seeks to analyze taken-for-granted assumptions and institutionalized practices seeking alternative perspectives and alternative sources of organizational knowledge. Exploring alternative perspectives from a critical lens recognizes the impact predominant discursive influences have on change management and the subsequent impact on organizational members’ working lives. This article will explore how Kincheloe’s discussions of the critical bricolage serve to support combining critical organizational methodologies (guided by Alvesson and Deetz with a voice-centered relational method of data analysis (guided by Brown and Gilligan to create a critical interpretive methodology that explores the voices of nurses as they experience rapid and continuous change in health care.

  16. The incorporation of displacement-controlled loadings within the net-section stress failure criterion

    International Nuclear Information System (INIS)

    Smith, E.

    1985-01-01

    A net-section stress failure criterion can be used to evaluate the critical flaw size for a material having a high fracture resistance. A simple analysis shows that the stress arising from displacement-controlled loadings should be taken into account fully if the applied tearing modulus exceeds a critical value. (author)

  17. Critical sizes and critical characteristics of nanoclusters, nanostructures and nanomaterials

    International Nuclear Information System (INIS)

    Suzdalev, I.P.

    2005-01-01

    Full text: Critical sizes and characteristics of nanoclusters and nanostructures are introduced as the parameters of nanosystems and nanomaterials. The next critical characteristics are considered: atomic and electronic 'magic number', critical size of cluster nucleation, critical size of melting-freezing of cluster, critical size of quantum (laser) radiation, critical sizes for the single electron conductivity, critical energy and magnetic field for the magnetic tunneling, critical cluster sizes for the giant magnetic resistance, critical size of the first order magnetic phase transition. The critical characteristics are estimated by thermodynamic approaches, by Moessbauer spectroscopy, AFM, heat capacity, SQUID magnetometry and other technique, The influence of cluster-cluster interactions, cluster-matrix interactions and cluster defects on cluster atomic dynamics, cluster melting, cluster critical sizes, Curie or Neel points and the character of magnetic phase transitions were investigated. The applications of critical size and critical characteristic parameters for the nanomaterial characterization are considered

  18. The Atlas load protection switch

    CERN Document Server

    Davis, H A; Dorr, G; Martínez, M; Gribble, R F; Nielsen, K E; Pierce, D; Parsons, W M

    1999-01-01

    Atlas is a high-energy pulsed-power facility under development to study materials properties and hydrodynamics experiments under extreme conditions. Atlas will implode heavy liner loads (m~45 gm) with a peak current of 27-32 MA delivered in 4 mu s, and is energized by 96, 240 kV Marx generators storing a total of 23 MJ. A key design requirement for Atlas is obtaining useful data for 95601130f all loads installed on the machine. Materials response calculations show current from a prefire can damage the load requiring expensive and time consuming replacement. Therefore, we have incorporated a set of fast-acting mechanical switches in the Atlas design to reduce the probability of a prefire damaging the load. These switches, referred to as the load protection switches, short the load through a very low inductance path during system charge. Once the capacitors have reached full charge, the switches open on a time scale short compared to the bank charge time, allowing current to flow to the load when the trigger pu...

  19. Cognitive Load of Learner Control: Extraneous or Germane Load?

    Directory of Open Access Journals (Sweden)

    Mieke Vandewaetere

    2013-01-01

    Full Text Available Computer-based learning environments become more tailored when learners can exert control over one or more parts of the learning process. Learner control (LC demands additional efforts of learners because, in addition to learning, they also have to monitor that learning. As a consequence, LC may cause additional cognitive load and even cognitive overload. The central question in this study is what type of cognitive load is induced by LC and whether the experienced load is related to learning outcomes. For this study, half of the students had control over task selection, while the other half had not. Within each condition, students were assigned to a single treatment, with the primary task to solely focus on the learning content, and a dual treatment, comprising a primary task and a secondary task. The results indicate that LC did not impose higher cognitive load as measured by secondary task scores and mental effort ratings.

  20. +Gz load and executive functions.

    Science.gov (United States)

    Biernacki, Marcin P; Tarnowski, Adam; Lengsfeld, Kamila; Lewkowicz, Rafał; Kowalczuk, Krzysztof; Dereń, Miroslaw

    2013-05-01

    Pilots are constantly exposed to a number of environmental factors, which include +Gz load. Physiological changes evoked by +Gz stimuli have already been well investigated in aviation medicine. However, the influence of +Gz stimulation on executive functions in pilots has not yet been thoroughly explored. There were 20 pilot cadets between the ages of 19 and 22 yr who volunteered to participate in the experiment. The subjects were divided into two groups: the G-load group, which was exposed to accelerations in the centrifuge, and the control group, which did not undergo this stimulation. Executive functions were assessed by means of the Schulte tables and the Rey-Osterrieth complex figure test. +Gz load exposure significantly improved attention switching. This relationship was valid for performance speed (M = 268.09 s in the pretest in the G-load group; M = 228.09 s in the posttest in the G-load group) and for the cumulative time of mistakes (M = 26.73 s in the pretest in the G-load group; M = 12 s in the posttest in the G-load group), whereas reproduction of visuospatial stimuli from memory deteriorated significantly under the influence of +Gz stimulation (M = 17.18 points in the posttest in the G-load group; M = 28.18 points in the posttest in the control group). These results suggest that the impact of +Gz load is not homogenous and unidirectional, since it improves attention switching but visuospatial working memory decreases under its influence. These aspects are particularly important for understanding the mechanisms responsible for maintaining situational awareness during the flight.

  1. Limit load assessment of centre cracked plates under biaxial loading

    International Nuclear Information System (INIS)

    Meek, C.; Ainsworth, R.A.

    2015-01-01

    Fitness-for-service of equipment and components containing defects is generally assessed using procedures such as BS 7910, API 579 and R6. There is currently little detailed advice in these procedures on the effects of biaxial and triaxial loading on fracture. This poster shows some theoretical bounding solutions of the plastic limit load for centre cracked plates under a variety of biaxial loading ratios and compares the estimates with those found by numerical methods using finite element (FE) analysis using Abacus CAE modelling software. The limit load of a structure is the maximum load that it can carry before plastic collapse occurs; this is often when the plastic zone has become large enough to spread from the crack tip to a remote boundary. For an elastic-perfectly plastic material, the irreversible deformation will continue at stresses no higher than the yield stress. The model for these limit load solutions is a bi-axially loaded plate of width 2W and height 2H, a centre crack of width 2a, acted on by remotely applied uniform stresses σ 2 perpendicular to the crack and Bσ 2 parallel to the crack, where B is the biaxial loading ratio, it means the ratio of the parallel to the perpendicular stress. A quarter plate of an elastic-perfectly plastic material has been modelled. The results show that an exact solution has been found for negative and low positive values of B. For B > 1, the lower bound solution is conservative for all values of a/W and B

  2. Uncertainty modelling of critical column buckling for reinforced ...

    Indian Academy of Sciences (India)

    Buckling is a critical issue for structural stability in structural design. In most of the buckling analyses, applied loads, structural and material properties are considered certain. However, in reality, these parameters are uncertain. Therefore, a prognostic solution is necessary and uncertainties have to be considered. Fuzzy logic ...

  3. Music critic Gustav Michel

    Directory of Open Access Journals (Sweden)

    Vasić Aleksandar N.

    2004-01-01

    Full Text Available The writers whose real vocation was not music left significant traces in the history of Serbian music critics and essayism of the late 19th century and the first half of the 20th century. Numerous authors, literary historians theoreticians and critics, jurists and theatre historians, wrote successfully on music in Serbian daily newspapers, literary and other magazines, until the Second World War. This study is devoted to Gustav Michel (1868 - 1926, one of the music amateurs who ought to be remembered in the history of Serbian music critics. Gustav Michel was a pharmacist by vocation. He ran a private pharmacy in Belgrade all his life. But he was a musician as well. He played the viola in the second (in chronological order of foundation Serbian String Quartet. The ensemble mostly consisted of amateurs, and it performed standard pieces of chamber music (W. A. Mozart L. v. Beethoven, F. Schubert, F. Mendelsohn-Bartholdy, A. Dvořžak. These musicians had performed public concerts in Belgrade since 1900 up until Michel’s death. Belgrade music critics prised the performances of this string ensemble highly. Gustav Michel was also a music critic. Until now only seven articles, published by this author between 1894 and 1903, in Order (Red, Folk Newspaper (Narodne novine and Serbian Literary Magazine (Srpski književni glasnik have been found. Michel’s preserved articles unambiguously prove that their author had a solid knowledge of music theory and history, the knowledge that exceeded amateurism. Nevertheless, Michel did not burden his first critics with expert language of musicology. Later on, in Serbian Literary Magazine, the magazine which left enough room for music, Michel penetrated more into musical terminology, thus educating slowly forming Serbian concert-going public. The analysis of Michel’s texts showed that he was not, in contrast to the majority of professional music critics, an opponent of virtuosity. Gentle and liberal, he did not

  4. Modeling of porous concrete elements under load

    Directory of Open Access Journals (Sweden)

    Demchyna B.H.

    2017-12-01

    Full Text Available It is known that cell concretes are almost immediately destroyed under load, having reached certain critical stresses. Such kind of destruction is called a “catastrophic failure”. Process of crack formation is one of the main factors, influencing process of concrete destruction. Modern theory of crack formation is mainly based on the Griffith theory of destruction. However, the mentioned theory does not completely correspond to the structure of cell concrete with its cell structure, because the theory is intended for a solid body. The article presents one of the possible variants of modelling of the structure of cell concrete and gives some assumptions concerning the process of crack formation in such hollow, not solid environment.

  5. Modeling of porous concrete elements under load

    Science.gov (United States)

    Demchyna, B. H.; Famuliak, Yu. Ye.; Demchyna, Kh. B.

    2017-12-01

    It is known that cell concretes are almost immediately destroyed under load, having reached certain critical stresses. Such kind of destruction is called a "catastrophic failure". Process of crack formation is one of the main factors, influencing process of concrete destruction. Modern theory of crack formation is mainly based on the Griffith theory of destruction. However, the mentioned theory does not completely correspond to the structure of cell concrete with its cell structure, because the theory is intended for a solid body. The article presents one of the possible variants of modelling of the structure of cell concrete and gives some assumptions concerning the process of crack formation in such hollow, not solid environment.

  6. Nuclear criticality information system

    International Nuclear Information System (INIS)

    Koponen, B.L.; Hampel, V.E.

    1981-01-01

    The nuclear criticality safety program at LLNL began in the 1950's with a critical measurements program which produced benchmark data until the late 1960's. This same time period saw the rapid development of computer technology useful for both computer modeling of fissile systems and for computer-aided management and display of the computational benchmark data. Database management grew in importance as the amount of information increased and as experimental programs were terminated. Within the criticality safety program at LLNL we began at that time to develop a computer library of benchmark data for validation of computer codes and cross sections. As part of this effort, we prepared a computer-based bibliography of criticality measurements on relatively simple systems. However, it is only now that some of these computer-based resources can be made available to the nuclear criticality safety community at large. This technology transfer is being accomplished by the DOE Technology Information System (TIS), a dedicated, advanced information system. The NCIS database is described

  7. CRISP. Intelligent load shedding. Deliverable 1.5

    International Nuclear Information System (INIS)

    Gajic, Z.; Karlsson, D.; Ullah, N.R.; Okuboye, S.; Andrieu, C.; Carlsson, P.

    2005-08-01

    Load shedding has been used to mitigate the consequences of large disturbances in electric power systems, since the beginning of the electrification era. The way to execute the load shedding, i.e. open a circuit breaker, has hardly developed at all for a 100-year period. The modern society dependence on reliable electricity supply is continuously increasing. This means that the consequences of traditional load shedding are not acceptable. In the meantime computer and communication technology has developed tremendously. There is also a trend to use more and more intelligent control and less hardware, such as lines and generators, to provide the required level of reliability for the electric supply. Especially in power systems, and parts of power systems, comprising distributed generation, there seems to be a great potential to improve the overall cost/benefit-ratio for the desired level of reliability, by the use of intelligent load shedding. Intelligent load shedding is a means to improve power system stability, by providing an adapted load control along the distribution network, in situations where the power system otherwise would go unstable. The work with intelligent load shedding in this work package results in various technical principles of dedicated algorithms. These algorithms intend to bring a support tool for the operating system during critical situations. The main aspects are evaluating the right amount and location of power response for a given disturbance, and evaluating the right time response expected in order to comply with an acceptable stability recover. This time response is a main object in order to define appropriate ICT network enabling such a reliable implementation. A main problem of the intelligent load shedding is how to choose load to shed conveniently and quickly. There is a technical problem of finding the right level and location of the load to shed, and also an economical problem of giving incentives in order to have enough remote

  8. Plutonium Immobilization Can Loading Concepts

    International Nuclear Information System (INIS)

    Kriikku, E.; Ward, C.; Stokes, M.; Randall, B.; Steed, J.; Jones, R.; Hamilton, L.; Rogers, L.; Fiscus, J.; Dyches, G.

    1998-05-01

    The Plutonium Immobilization Facility will encapsulate plutonium in ceramic pucks and seal the pucks inside welded cans. Remote equipment will place these cans in magazines and the magazines in a Defense Waste Processing Facility (DWPF) canister. The DWPF will fill the canister with glass for permanent storage. This report discusses five can loading conceptual designs and the lists the advantages and disadvantages for each concept. This report identifies loading pucks into cans and backfilling cans with helium as the top priority can loading development areas. The can loading welder and cutter are very similar to the existing Savannah River Site (SRS) FB-Line bagless transfer welder and cutter and thus they are a low priority development item

  9. Structural Impact of Construction Loads

    Science.gov (United States)

    2012-08-01

    Numerous bridge construction accidents have occurred across the country because of construction loadings, which are an underemphasized : topic in many DOT specifications and design manuals. Bridge girders are least stable when they are subjected to c...

  10. Nuclear fuel pellet loading machine

    International Nuclear Information System (INIS)

    Kee, R.W.; Denero, J.V.

    1975-01-01

    An apparatus for loading nuclear fuel pellets on trays for transfer in a system is described. A conveyor supplies pellets from a source to a loading station. When the pellets reach a predetermined position at the loading station, a manual or automatically operated arm pushes the pellets into slots on a tray and this process is repeated until pellet sensing switches detect that the tray is full. Thereupon, the tray is lowered onto a belt or other type conveyor and transferred to other apparatus in the system, such as a furnace for sintering, and in some cases, reduction of UO 2 . 2 to UO 2 . The pellets are retained on the tray and subsequently loaded directly into fuel rods to be used in the reactor core. (auth)

  11. The initial criticality and nuclear commissioning test program at HANARO

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Choong-Sung; Seo, Chul-Gyo; Jun, Byung-Jin [Korea Atomic Energy Research Institute, Dukjin-Dong 150, Yusung-Ku, Taejon, 305-353 (Korea, Republic of)

    1995-07-01

    The construction of the Korea Multipurpose Research Reactor - HANARO of 3MW, developed by Korea Atomic Energy Research Institute, was completed at the beginning of this year. The first fuel loading began on February 2 1995, and initial criticality was achieved on February 8, when the core had four 18-element assemblies and thirteen 36-element assemblies. The critical control rod position was 600.8 mm which represents excess reactivity of 0.71 $. Currently the nuclear commissioning test is on going under the zero power range. This paper describes the initial criticality approach of the HANARO, and its nuclear commissioning test program. (author)

  12. Load Test in Sheet Pile

    OpenAIRE

    Luis Orlando Ibanez

    2016-01-01

    In this work, are discussed experiences in the use of mathematical modeling and testing in hydraulic engineering structures. For this purpose the results of load tests in sheet pile, evaluating horizontal and vertical deformations that occur in the same exposed. Comparisons between theoretical methods for calculating deformations and mathematical models based on the Finite Element Method are established. Finally, the coincidence between the numerical model and the results of the load test ful...

  13. Fuel rod pellet loading head

    International Nuclear Information System (INIS)

    Howell, T.E.

    1975-01-01

    An assembly for loading nuclear fuel pellets into a fuel rod comprising a loading head for feeding pellets into the open end of the rod is described. The pellets rest in a perforated substantially V-shaped seat through which air may be drawn for removal of chips and dust. The rod is held in place in an adjustable notched locator which permits alignment with the pellets

  14. The critical ionization velocity

    International Nuclear Information System (INIS)

    Raadu, M.A.

    1980-06-01

    The critical ionization velocity effect was first proposed in the context of space plasmas. This effect occurs for a neutral gas moving through a magnetized plasma and leads to rapid ionization and braking of the relative motion when a marginal velocity, 'the critical velocity', is exceeded. Laboratory experiments have clearly established the significance of the critical velocity and have provided evidence for an underlying mechanism which relies on the combined action of electron impact ionization and a collective plasma interaction heating electrons. There is experimental support for such a mechanism based on the heating of electrons by the modified two-stream instability as part of a feedback process. Several applications to space plasmas have been proposed and the possibility of space experiments has been discussed. (author)

  15. Critical Kinship Studies

    DEFF Research Database (Denmark)

    In recent decades the concept of kinship has been challenged and reinvigorated by the so-called “repatriation of anthropology” and by the influence of feminist studies, queer studies, adoption studies, and science and technology studies. These interdisciplinary approaches have been further...... developed by increases in infertility, reproductive travel, and the emergence of critical movements among transnational adoptees, all of which have served to question how kinship is now practiced. Critical Kinship Studies brings together theoretical and disciplinary perspectives and analytically sensitive...... in the Humanities and Social Sciences today. Critical Kinship Studies should be of particular interest to students and scholars in Anthropology, Sociology, Cultural Studies, Medical Humanities, Politics, Gender and Queer Studies and Globalization....

  16. Constructing criticality by classification

    DEFF Research Database (Denmark)

    Machacek, Erika

    2017-01-01

    " in the bureaucratic practice of classification: Experts construct material criticality in assessments as they allot information on the materials to the parameters of the assessment framework. In so doing, they ascribe a new set of connotations to the materials, namely supply risk, and their importance to clean energy......, legitimizing a criticality discourse.Specifically, the paper introduces a typology delineating the inferences made by the experts from their produced recommendations in the classification of rare earth element criticality. The paper argues that the classification is a specific process of constructing risk....... It proposes that the expert bureaucratic practice of classification legitimizes (i) the valorisation that was made in the drafting of the assessment framework for the classification, and (ii) political operationalization when enacted that might have (non-)distributive implications for the allocation of public...

  17. Thermal loading study for FY 1995

    International Nuclear Information System (INIS)

    1996-01-01

    This report provides the results of sensitivity analyses designed to assist the test planners in focusing their in-situ measurements on parameters that appear to be important to waste isolation. Additionally, the study provides a preliminary assessment of the feasibility of certain thermal management options. A decision on thermal loading is a critical part of the scientific and engineering basis for evaluating regulatory compliance of the potential repository for waste isolation. To show, with reasonable assurance, that the natural and engineered barriers will perform adequately under expected repository conditions (thermally perturbed) will require an integrated approach based on thermal testing (laboratory, and in-situ), natural analog observations, and analytic modeling. The Office of Civilian Radioactive Waste Management needed input to assist in the planning of the thermal testing program. Additionally, designers required information on the viability of various thermal management concepts. An approximately 18-month Thermal Loading Study was conducted from March, 1994 until September 30, 1995 to address these issues. This report documents the findings of that study. 89 refs., 71 figs., 33 tabs

  18. Drug Loading of Mesoporous Silicon

    Science.gov (United States)

    Moffitt, Anne; Coffer, Jeff; Wang, Mengjia

    2011-03-01

    The nanostructuring of crystalline solids with low aqueous solubilities by their incorporation into mesoporous host materials is one route to improve the bioavailability of such solids. Earlier studies suggest that mesoporous Si (PSi), with pore widths in the range of 5-50 nm, is a candidate for such an approach. In this presentation, we describe efforts to load curcumin into free-standing microparticles of PSi. Curcumin is a compound extracted from turmeric root, which is an ingredient of curry. Curucmin has shown activity against selected cancer cell lines, bacteria, and other medical conditions. However, curcumin has a very low bioavailability due to its extremely low water solubility (0.6 μ g/mL). Incorporation of curcumin was achieved by straightforward loading of the molten solid at 185circ; C. Loading experiments were performed using PSi particles of two different size ranges, 45-75 μ m and 150-250 μ m. Longer loading times and ratio of curcumin to PSi leads to a higher percentage of loaded curcumin in both PSi particle sizes (as determined by weight difference). The extent of curcumin crystallinity was assessed by x-ray diffraction (XRD). The solubility and release kinetics of loaded curcumin from the PSi was determined by extraction into water at 37circ; C, with analysis using UV-VIS spectrometry. NSF-REU and TCU.

  19. Environmental Aspects of Load Management

    International Nuclear Information System (INIS)

    Abaravicius, Juozas

    2004-02-01

    This study approaches load management from an environmental perspective. It identifies and discusses the possible environmental benefits of load management and evaluates their significance, primary focusing on CO 2 emissions reduction. The analysis is carried out on two levels: national - the Swedish electricity market, and local - one electric utility in southern Sweden. Our results show the importance of considering the influence of site-specific or level-specific conditions on the environmental effects of load management. On the national level, load management measures can hardly provide significant environmental benefits, due to the high hydropower production in Sweden, which is the demand following production source. Emission reductions will rather be the result of energy efficiency measures, which will cut the load demand as well as the energy demand. However, when it comes to a local (utility) level, where load management is considered as an alternative to an installation of peak diesel power plant, the benefits are clear. It is demonstrated that significant CO 2 emissions savings can be achieved due to avoided peak diesel power production

  20. Nuclear multifragmentation critical exponents

    International Nuclear Information System (INIS)

    Bauer, W.; Friedman, W.A.; Univ. of Wisconsin, Madison, WI

    1995-01-01

    In a recent Letter, cited in a reference, the EoS collaboration presented data of fragmentation of 1 A GeV gold nuclei incident on carbon. By analyzing moments of the fragment charge distribution, the authors claim to determine the values of the critical exponents γ, β, and τ for finite nuclei. These data represent a crucial step forward in the understanding of the physics of nuclear fragmentation. However, as shown in this paper, the analysis presented in the cited reference is not sufficient to support the claim that the critical exponents for nuclear fragmentation have been unambiguously determined

  1. A strategy for load balancing in distributed storage systems

    CERN Multimedia

    CERN. Geneva

    2012-01-01

    Distributed storage systems are critical to the operation of the WLCG. These systems are not limited to fulfilling the long term storage requirements. They also serve data for computational analysis and other computational jobs. Distributed storage systems provide the ability to aggregate the storage and IO capacity of disks and tapes, but at the end of the day IO rate is still bound by the capabilities of the hardware, in particular the hard drives. Throughput of hard drives has increased dramatically over the decades, however for computational analysis IOPS is typically the limiting factor. To maximize return of investment, balancing IO load over available hardware is crucial. The task is made complicated by the common use of heterogeneous hardware and software environments that results from combining new and old hardware into a single storage system. This paper describes recent advances made in load balancing in the dCache distributed storage system. We describe a set of common requirements for load balan...

  2. Postbuckling Analysis Of A Rectangular Plate Loaded In Compression

    Directory of Open Access Journals (Sweden)

    Havran Jozef

    2015-12-01

    Full Text Available The stability analysis of a thin rectangular plate loaded in compression is presented. The nonlinear FEM equations are derived from the minimum total potential energy principle. The peculiarities of the effects of the initial imperfections are investigated using the user program. Special attention is paid to the influence of imperfections on the post-critical buckling mode. The FEM computer program using a 48 DOF element has been used for analysis. Full Newton-Raphson procedure has been applied.

  3. Performance of multifilamentary Nb3Sn under mechanical load

    International Nuclear Information System (INIS)

    Easton, D.S.; Schwall, R.E.

    1976-01-01

    The critical current of a commercial multifilamentary Nb 3 Sn conductor has been measured under the application of uniaxial tension at 4.2 K and following bending at room temperature. Significant reductions in J/subc/ are observed under uniaxial loading. Results are presented for a monolithic conductor manufactured by the bronze diffusion technique and for cable conductors formed by the tin-dip technique

  4. Pebble bed test reactor in peu-a-peu load

    International Nuclear Information System (INIS)

    Kranz, L.

    1988-03-01

    The presented work deals with a new type of load model for high temperature reactors with spherical fuels: the peu-a-peu load system. Using this load system the reactor core is only filled partially in the beginning of the power operation. But it has to be a critical base core. With proceeding burn-off the reactor is filled up with further fuel elements the way that it stays always just critically. When the reactor is filled up completely with fuel elements, the reactor operation has to be interrupted and the reactor has to be discharged. Afterwards a new cycle can start like the one just described. A reference reactor with 100 MW thermal power is investigated in this work in detail and should make clear the way of function of the load system and the base idea of 'simplicity and safety'. The improvement proposal to use again a part of the fuel elements of a cycle for the next cycle minimizes the higher specific uranium need of a peu-a-peu reactor decisively. (orig.) [de

  5. Buckling of Flat Thin Plates under Combined Loading

    Directory of Open Access Journals (Sweden)

    Ion DIMA

    2015-03-01

    Full Text Available This article aims to provide a quick methodology to determine the critical values of the forces applied to the central plane of a flat isotropic plate at which a change to the stable configuration of equilibrium occurs. Considering the variety of shapes, boundary conditions and loading combinations, the article does not intend to make an exhaustive presentation of the plate buckling. As an alternative, there will be presented only the most used configurations such as: rectangular flat thin plates, boundary conditions with simply supported (hinged or clamped (fixed edges, combined loadings with single compression or single shear or combination between them, compression and shear, with or without transverse loading, encountered at wings and control surfaces shell of fin and rudder or stabilizer and elevator. The reserve factor and the critical stresses will be calculated using comparatively two methods, namely the methodology proposed by the present article and ASSIST 6.6.2.0 – AIRBUS France software, a dedicated software to local calculations, for a simply supported plate under combined loading, compression on the both sides and shear.

  6. The effects of load drop, uniform load and concentrated loads on waste tanks

    International Nuclear Information System (INIS)

    Marusich, R.M. Westinghouse Hanford

    1996-01-01

    This document provides the supporting calculations performed by others specifically for the TWRS FSAR and more detailed summaries of the important references issued in the past regarding the effects of various loads

  7. Power Load Prediction Based on Fractal Theory

    OpenAIRE

    Jian-Kai, Liang; Cattani, Carlo; Wan-Qing, Song

    2015-01-01

    The basic theories of load forecasting on the power system are summarized. Fractal theory, which is a new algorithm applied to load forecasting, is introduced. Based on the fractal dimension and fractal interpolation function theories, the correlation algorithms are applied to the model of short-term load forecasting. According to the process of load forecasting, the steps of every process are designed, including load data preprocessing, similar day selecting, short-term load forecasting, and...

  8. Identification of Critical Transmission Limits in Injection Impedance Plane

    DEFF Research Database (Denmark)

    Jóhannsson, Hjörtur; Østergaard, Jacob; Nielsen, Arne Hejde

    2012-01-01

    In this paper, equations are derived that describe the mapping of critical boundaries and characteristic lines from the three dimensionalPQV-surface into the two-dimensional injection impedance plane (load impedance plane for both positive and negativeresistance). The expressions derived....... The situational awareness method will bedescribed in a later paper, where this paper focuses on the derivations of some system characteristics in the injection (or load)impedance plane. The critical lines from the PQV-surface that are mapped into the impedance plane are the ones representing theconditions where...... the partial derivatives of the variables P,Q and V in respect to each other become zero. In addition to the mappingof the critical lines, some characteristic lines are mapped as well. These include the mapping of the lines of constant P,Q,Vand d from the PQV-surface into the impedance plane. All of the mapped...

  9. Trust and Critical Thinking

    Science.gov (United States)

    Kleinig, John

    2018-01-01

    This article discusses the tension between trust, as an expression of interpersonal commitment, and critical thinking, which includes a demand for reasons. It explores the importance of each for individual flourishing, and then seeks to establish some ways in which they intersect, drawing on ideas of authority and trustworthiness. It argues that…

  10. Posthuman Critical Theory

    NARCIS (Netherlands)

    Braidotti, R.

    2016-01-01

    This essay proposes a genealogical cartography of the emergence of a posthuman turn in critical theory, including feminist theory, based on the convergence of posthumanism with post-anthropocentrism. The former critiques the universalist posture of the idea of ‘Man’ as the alleged ‘measure of all

  11. Critical scattering by bubbles

    International Nuclear Information System (INIS)

    Fiedler-Ferrari, N.; Nussenzveig, H.M.

    1986-11-01

    We apply the complex angular momentum theory to the problem of the critical scattering of light by spherical cavities in the high frequency limit (permittivity greater than the external media) (e.g, air bubble in water) (M.W.O.) [pt

  12. The critical interface

    DEFF Research Database (Denmark)

    Pold, Søren

    2005-01-01

    In this paper, I argue that aesthetics might serve the role of critical reflection on representation within the field of computing, and I demonstrate through three analytic examples from computer art how this might look like and what the contribution might be....

  13. Reply to critics

    NARCIS (Netherlands)

    Lindahl, H.K.

    2014-01-01

    In my reply to critics I address a raft of issues raised by the commentators to Fault Lines of Globalization. These issues include: the radicalization of the Husserlian concept of intentionality as differance; the irreducibility of a-legality to (il)legality; the relation between legal orders and

  14. Critical Practice: Teaching "Shakespeare."

    Science.gov (United States)

    Mellor, Bronwyn; Patterson, Annette

    2000-01-01

    Describes how the authors taught their students to read "Hamlet" from a critical literacy perspective, analyzing how particular readings of texts and characters are constructed or produced; how they are determined by historical and cultural conventions; analyzing values that various readings support or challenge--rather than trying to…

  15. Alternative methods in criticality

    International Nuclear Information System (INIS)

    Pedicini, J.M.

    1982-01-01

    In this thesis two new methods of calculating the criticality of a nuclear system are introduced and verified. Most methods of determining the criticality of a nuclear system depend implicitly upon knowledge of the angular flux, net currents, or moments of the angular flux, on the system surface in order to know the leakage. For small systems, leakage is the predominant element in criticality calculations. Unfortunately, in these methods the least accurate fluxes, currents, or moments are those occurring near system surfaces or interfaces. This is due to a mathematical inability to satisfy rigorously with a finite order angular polynomial expansion or angular difference technique the physical boundary conditions which occur on these surfaces. Consequently, one must accept large computational effort or less precise criticality calculations. The methods introduced in this thesis, including a direct leakage operator and an indirect multiple scattering leakage operator, obviate the need to know angular fluxes accurately at system boundaries. Instead, the system wide scalar flux, an integral quantity which is substantially easier to obtain with good precision is sufficient to obtain production, absorption, scattering, and leakage rates

  16. Critical groups - basic concepts

    International Nuclear Information System (INIS)

    Carter, M.W.

    1992-01-01

    The potential exposure pathways from the land application site to man are presented. It is emphasised that the critical group is not necessary the population group closest to the source. It could be the group impact by the most significant pathways(s). Only by assessing the importance of each of these pathways and then combining them can a proper choice of critical group be made. It would be wrong to select a critical group on the basis that it seems the most probable one, before the pathways have been properly assessed. A calculation in Carter (1983) suggested that for the operating mine site, the annual doses to an Aboriginal person, a service worker and a local housewife, were all about the same and were in the range 0.1 to 0.2 mSv per year. Thus it may be that for the land application area, the critical group turns out to be non-Aboriginal rather than the expected Aboriginal group. 6 refs., 3 figs

  17. Criticality accident in Argentina

    International Nuclear Information System (INIS)

    Oliveira, A.R. de.

    1984-01-01

    A recent criticality type accident, ocurred in Argetina, is commented. Considerations about the nature of the facility where this accident took place, its genesis, type of operation carried out on the day of the event, and the medical aspects involved are done. (Author) [pt

  18. APS Quantum Critical Higgs

    CERN Document Server

    Bellazzini, Brando; Hubisz, Jay; Lee, Seung J.; Serra, Javi; Terning, John

    2016-01-01

    The appearance of the light Higgs boson at the LHC is difficult to explain, particularly in light of naturalness arguments in quantum field theory. However light scalars can appear in condensed matter systems when parameters (like the amount of doping) are tuned to a critical point. At zero temperature these quantum critical points are directly analogous to the finely tuned standard model. In this paper we explore a class of models with a Higgs near a quantum critical point that exhibits non-mean-field behavior. We discuss the parametrization of the effects of a Higgs emerging from such a critical point in terms of form factors, and present two simple realistic scenarios based on either generalized free fields or a 5D dual in AdS space. For both of these models we consider the processes $gg\\to ZZ$ and $gg\\to hh$, which can be used to gain information about the Higgs scaling dimension and IR transition scale from the experimental data.

  19. Comment on critical instability

    International Nuclear Information System (INIS)

    King, S.F.; Suzuki, Mahiko

    1992-01-01

    We discuss the problem of the mass splitting between top and bottom quarks, within the context of Nambu-Jona-Lasinio type models involving top and bottom quark condensates. We interpret the phenomenon of 'critical instability' recently proposed to account for such a mass splitting as the fine-tuning of two vacuum expectation values in a composite two-Higgs doublet model. (orig.)

  20. Alternative methods in criticality

    International Nuclear Information System (INIS)

    Pedicini, J.M.

    1982-01-01

    Two new methods of calculating the criticality of a nuclear system are introduced and verified. Most methods of determining the criticality of a nuclear system depend implicitly upon knowledge of the angular flux, net currents, or moments of the angular flux, on the system surface in order to know the leakage. For small systems, leakage is the predominant element in criticality calculations. Unfortunately, in these methods the least accurate fluxes, currents, or moments are those occuring near system surfaces or interfaces. This is due to a mathematical inability to satisfy rigorously with a finite order angular polynomial expansion or angular difference technique the physical boundary conditions which occur on these surfaces. Consequently, one must accept large computational effort or less precise criticality calculations. The methods introduced in this thesis, including a direct leakage operator and an indirect multiple scattering leakage operator, obviate the need to know angular fluxes accurately at system boundaries. Instead, the system wide scalar flux, an integral quantity which is substantially easier to obtain with good precision, is sufficient to obtain production, absorption, scattering, and leakage rates

  1. Quantum Critical Higgs

    Science.gov (United States)

    Bellazzini, Brando; Csáki, Csaba; Hubisz, Jay; Lee, Seung J.; Serra, Javi; Terning, John

    2016-10-01

    The appearance of the light Higgs boson at the LHC is difficult to explain, particularly in light of naturalness arguments in quantum field theory. However, light scalars can appear in condensed matter systems when parameters (like the amount of doping) are tuned to a critical point. At zero temperature these quantum critical points are directly analogous to the finely tuned standard model. In this paper, we explore a class of models with a Higgs near a quantum critical point that exhibits non-mean-field behavior. We discuss the parametrization of the effects of a Higgs emerging from such a critical point in terms of form factors, and present two simple realistic scenarios based on either generalized free fields or a 5D dual in anti-de Sitter space. For both of these models, we consider the processes g g →Z Z and g g →h h , which can be used to gain information about the Higgs scaling dimension and IR transition scale from the experimental data.

  2. Assessment of criticality safety

    International Nuclear Information System (INIS)

    Lloyd, R.C.; Heaberlin, S.W.; Clayton, E.D.; Carter, R.D.

    1979-01-01

    A study was made of 100 violations of criticality safety specifications reported over a 10-y period in the operations of fuel reprocessing plants. The seriousness of each rule violation was evaluated by assigning it a severity index value. The underlying causes or reasons, for the violations were identified. A criticality event tree was constructed using the parameters, causes, and reasons found in the analysis of the infractions. The event tree provides a means for visualizing the paths to an accidental criticality. Some 65% of the violations were caused by misinterpretation on the part of the operator, being attributed to a lack of clarity in the specification and insufficient training; 33% were attributed to lack of care, whereas only 2% were caused by mechanical failure. A fault tree was constructed by assembling the events that could contribute to an accident. With suitable data on the probabilities of contributing events, the probability of the accident's occurrence can be forecast. Estimated probabilities for criticality were made, based on the limited data available, that in this case indicate a minimum time span of 244 y of plant operation per accident ranging up to approx. 3000 y subject to the various underlying assumptions made. Some general suggestions for improvement are formulated based on the cases studied. Although conclusions for other plants may differ in detail, the general method of analysis and the fault tree logic should prove applicable. 4 figures, 8 tables

  3. Critical theory and holocaust

    Directory of Open Access Journals (Sweden)

    Krstić Predrag

    2006-01-01

    Full Text Available In this paper the author is attempting to establish the relationship - or the lack of it - of the Critical Theory to the "Jewish question" and justification of perceiving signs of Jewish religious heritage in the thought of the representatives of this movement. The holocaust marked out by the name of "Auschwitz", is here tested as a point where the nature of this relationship has been decided. In this encounter with the cardinal challenge for the contemporary social theory, the particularity of the Frankfurt School reaction is here revealed through Adorno installing Auschwitz as unexpected but lawful emblem of the ending of the course that modern history has assumed. The critique of this "fascination" with Auschwitz, as well as certain theoretical pacification and measured positioning of the holocaust into discontinued plane of "unfinished" and continuation and closure of the valued project, are given through communicative-theoretical pre-orientation of Jürgen Habermas’s Critical Theory and of his followers. Finally, through the work of Detlev Claussen, it is suggested that in the youngest generation of Adorno’s students there are signs of revision to once already revised Critical Theory and a kind of defractured and differentiated return to the initial understanding of the decisiveness of the holocaust experience. This shift in the attitude of the Critical Theory thinkers to the provocation of holocaust is not, however, particularly reflected towards the status of Jews and their tradition, but more to the age old questioning and explanatory patterns for which they served as a "model". The question of validity of the enlightenment project, the nature of occidental rationalism, (nonexistence of historical theology and understanding of the identity and emancipation - describe the circle of problems around which the disagreement is concentrated in the social critical theory.

  4. Load bearing capacities and elastic-plastic behavior of reactor vessel internals

    International Nuclear Information System (INIS)

    Watanabe, Keita; Nagase, Ryuichi

    2017-01-01

    Radial Support Keys (RSKs) are installed at the bottom of Reactor Vessel Internal (RVI) of Pressurized Water Reactor (PWR) and fit into Core Support Lugs of Reactor Pressure Vessel (RPV). This structure provides reactor core horizontal support and transmits the loads between RVI and RPV. RSK is one of the critical parts of RVI from the view point of earthquake-proof safety. In order to assure the structural integrity of Nuclear Reactor in case of massive earthquake, load bearing capacities of RSK are confirmed by static loading tests with reduced-scale mockups. In addition, collapse loads of actual components calculated by Limit Analyses are conservative enough compared to the load bearing capacities confirmed by the test. Thus, the methodology to calculate collapse load by Limit Analysis is applicable to evaluation of structural integrity for RSK. (author)

  5. Study on load test of 100m cross-reinforced deck type concrete box arch bridge

    Science.gov (United States)

    Shi, Jing Xian; Cheng, Ying Jie

    2018-06-01

    Found in the routine quality inspection of highway bridge that many vertical fractures on the main beam (10mT beam) of the steel reinforced concrete arch bridge near the hydropower station. In order to grasp the bearing capacity of this bridge under working conditions with cracks, the static load and dynamic load test of box arch bridge are carried out. The Midas civil theory is calculated by using the special plate trailer - 300 as the calculation load, and the deflection and stress of the critical section are tested by the equivalent cloth load in the test vehicle. The pulsation test, obstacles and no obstacle driving test were carried out. Experimental results show that the bridge under the condition of the test loads is in safe condition, main bearing component of the strength and stiffness meet the design requirements, the crack width does not increase, in the process of loading bridge overall work performance is good.

  6. Critical Education, Critical Pedagogies, Marxist Education in the United States

    Science.gov (United States)

    Foley, Jean Ann; Morris, Doug; Gounari, Panayota; Agostinone-Wilson, Faith

    2015-01-01

    As critical pedagogy becomes more mainstream on the educational landscape in the United States, it is important to revisit the original tenets of critical pedagogy and explore their current manifestations. Since the beginning of "criticalism" from the theoretical/foundational work of the Frankfurt School of Critical Social Theory,…

  7. A gravity loading countermeasure skinsuit

    Science.gov (United States)

    Waldie, James M.; Newman, Dava J.

    2011-04-01

    Despite the use of several countermeasures, significant physiological deconditioning still occurs during long duration spaceflight. Bone loss - primarily due to the absence of loading in microgravity - is perhaps the greatest challenge to resolve. This paper describes a conceptual Gravity Loading Countermeasure Skinsuit (GLCS) that induces loading on the body to mimic standing and - when integrated with other countermeasures - exercising on Earth. Comfort, mobility and other operational issues were explored during a pilot study carried out in parabolic flight for prototype suits worn by three subjects. Compared to the 1- or 2-stage Russian Pingvin Suits, the elastic mesh of the GLCS can create a loading regime that gradually increases in hundreds of stages from the shoulders to the feet, thereby reproducing the weight-bearing regime normally imparted by gravity with much higher resolution. Modelling shows that the skinsuit requires less than 10 mmHg (1.3 kPa) of compression for three subjects of varied gender, height and mass. Negligible mobility restriction and excellent comfort properties were found during the parabolic flights, which suggests that crewmembers should be able to work normally, exercise or sleep while wearing the suit. The suit may also serve as a practical 1 g harness for exercise countermeasures and vibration applications to improve dynamic loading.

  8. Pattern fuel assembly loading system

    International Nuclear Information System (INIS)

    Ahmed, H.J.; Gerkey, K.S.; Miller, T.W.; Wylie, M.E.

    1986-01-01

    This patent describes an interactive system for facilitating preloading of fuel rods into magazines, which comprises: an operator work station adapted for positioning between a supply of fuel rods of predetermined types, and the magazine defining grid locations for a predetermined fuel assembly; display means associated with the work station; scanner means associated with the work station and adapted for reading predetermined information accompanying the fuel rods; a rectangular frame adapted for attachment to one end of the fuel assembly loading magazine; prompter/detector means associated with the frame for detecting insertion of a fuel rod into the magazine; and processing means responsive to the scanner means and the sensing means for prompting the operator via the display means to pre-load the fuel rods into desired grid locations in the magazine. An apparatus is described for facilitating pre-loading of fuel rods in predetermined grid locations of a fuel assembly loading magazine, comprising: a rectangular frame adapted for attachment to one end of the fuel assembly loading magazine; and means associated with the frame for detecting insertion of fuel rods into the magazine

  9. Friction and anchorage loading revisited.

    Science.gov (United States)

    Dholakia, Kartik D

    2012-01-01

    Contemporary concepts of sliding mechanics explain that friction is inevitable. To overcome this frictional resistance, excess force is required to retract the tooth along the archwire (ie, individual retraction of canines, en masse retraction of anterior teeth), in addition to the amount of force required for tooth movement. The anterior tooth retraction force, in addition to excess force (to overcome friction), produces reciprocal protraction force on molars, thereby leading to increased anchorage loading. However, this traditional concept was challenged in recent literature, which was based on the finite element model, but did not bear correlation to the clinical scenario. This article will reinforce the fact that clinically, friction increases anchorage loading in all three planes of space, considering the fact that tooth movement is a quasistatic process rather than a purely continuous or static one, and that conventional ways of determining the effects of static or dynamic friction on anchorage load cannot be applied to clinical situations (which consist of anatomical resistance units and a complex muscular force system). The article does not aim to quantify friction and its effect on the amount of anchorage load. Rather, a new perspective regarding the role of various additional factors (which is not explained by contemporary concept) that may influence friction and anchorage loading is provided..

  10. Failure mitigation in software defined networking employing load type prediction

    KAUST Repository

    Bouacida, Nader

    2017-07-31

    The controller is a critical piece of the SDN architecture, where it is considered as the mastermind of SDN networks. Thus, its failure will cause a significant portion of the network to fail. Overload is one of the common causes of failure since the controller is frequently invoked by new flows. Even through SDN controllers are often replicated, the significant recovery time can be an overkill for the availability of the entire network. In order to overcome the problem of the overloaded controller failure in SDN, this paper proposes a novel controller offload solution for failure mitigation based on a prediction module that anticipates the presence of a harmful long-term load. In fact, the long-standing load would eventually overwhelm the controller leading to a possible failure. To predict whether the load in the controller is short-term or long-term load, we used three different classification algorithms: Support Vector Machine, k-Nearest Neighbors, and Naive Bayes. Our evaluation results demonstrate that Support Vector Machine algorithm is applicable for detecting the type of load with an accuracy of 97.93% in a real-time scenario. Besides, our scheme succeeded to offload the controller by switching between the reactive and proactive mode in response to the prediction module output.

  11. Heat loads on Tore Supra ICRF Launchers Plasma Facing Components

    International Nuclear Information System (INIS)

    Bremond, S.; Colas, L.; Beaumont, B.; Chantant, M.; Goniche, M.; Mitteau, R.

    2005-01-01

    Understanding the heat loads on Ion Cyclotron Range of Frequency (ICRF) launchers plasma-facing components is a crucial task both for operating present tokamaks and for designing ITER ICRF launchers as these loads may limit the RF power coupling capability. Tore Supra facility is particularly well suited to take this issue. Parametric studies have been performed which enables to get an overall detailed picture of the different heat loads on several areas, pointing to different mechanisms at the origin of the heat power fluxes. It is found that the most critical items for Tore-Supra operation are localized heat loads on the Faraday screen top left corner and vertical edges. Warming up close to maximum temperature limit originally set for protection of the plasma-facing components is found of high power pulses, but no erosion was observed after detailed inspection of the launcher in Tore-Supra vessel. Yet, the associated heat loads could be limiting for Tore-Supra operation in the future, and some dedicated work is under progress to improve the understanding of these power fluxes, pointing out the importance of getting a better knowledge of particle flows in the scrape of layer

  12. Surface Damage Mechanism of Monocrystalline Si Under Mechanical Loading

    Science.gov (United States)

    Zhao, Qingliang; Zhang, Quanli; To, Suet; Guo, Bing

    2017-03-01

    Single-point diamond scratching and nanoindentation on monocrystalline silicon wafer were performed to investigate the surface damage mechanism of Si under the contact loading. The results showed that three typical stages of material removal appeared during dynamic scratching, and a chemical reaction of Si with the diamond indenter and oxygen occurred under the high temperature. In addition, the Raman spectra of the various points in the scratching groove indicated that the Si-I to β-Sn structure (Si-II) and the following β-Sn structure (Si-II) to amorphous Si transformation appeared under the rapid loading/unloading condition of the diamond grit, and the volume change induced by the phase transformation resulted in a critical depth (ductile-brittle transition) of cut (˜60 nm ± 15 nm) much lower than the theoretical calculated results (˜387 nm). Moreover, it also led to abnormal load-displacement curves in the nanoindentation tests, resulting in the appearance of elbow and pop-out effects (˜270 nm at 20 s, 50 mN), which were highly dependent on the loading/unloading conditions. In summary, phase transformation of Si promoted surface deformation and fracture under both static and dynamic mechanical loading.

  13. Fifty years of genetic load

    International Nuclear Information System (INIS)

    Wallace, B.

    1991-01-01

    This book discusses the radiation effects on Drosophila. It was originally thought that irradiating Drosophila would decrease the average fitness of the population, thereby leading to information about the detrimental effects of mutations. Surprisingly, the fitness of the irradiated population turned out to be higher than that of the control population. The original motivation for the experiment was as a test of genetic load theory. The average fitness of a population is depressed by deleterious alleles held in the population by the balance between mutation and natural selection. The depression is called the genetic load of the population. The load dose not depend on the magnitude of the deleterious effect of alleles, but only on the mutation rate

  14. Efficiency of Capacitively Loaded Converters

    DEFF Research Database (Denmark)

    Andersen, Thomas; Huang, Lina; Andersen, Michael A. E.

    2012-01-01

    This paper explores the characteristic of capacitance versus voltage for dielectric electro active polymer (DEAP) actuator, 2kV polypropylene film capacitor as well as 3kV X7R multi layer ceramic capacitor (MLCC) at the beginning. An energy efficiency for capacitively loaded converters...... is introduced as a definition of efficiency. The calculated and measured efficiency curves for charging DEAP actuator, polypropylene film capacitor and X7R MLCC are provided and compared. The attention has to be paid for the voltage dependent capacitive load, like X7R MLCC, when evaluating the charging...... polypropylene film capacitor can be the equivalent capacitive load. Because of the voltage dependent characteristic, X7R MLCC cannot be used to replace the DEAP actuator. However, this type of capacitor can be used to substitute the capacitive actuator with voltage dependent property at the development phase....

  15. Critical Digital Tourism Studies

    DEFF Research Database (Denmark)

    Gyimóthy, Szilvia; Munar, Ana María

    2013-01-01

    This paper advocates the need for a critical and cross-disciplinary research agenda on the field of digital technologies and tourism. The changing virtual landscape of tourism has received increased attention by tourism scholars. However, contemporary studies on information technologies (IT......) are approached mostly from a business administration perspective and informed by conceptual frameworks developed in management and marketing. IT studies in tourism are still at a stage similar to the first advocacy phase of tourism research in general (Jafari, 1990) and are seldom inspired by relevant...... to studying digital socio-technical systems and virtual mediation in tourism. Critical Digital Tourism Studies opens a new cross-disciplinary field where the sociality of virtual tourism interactions is examined (entailing the study of structures, social rules, ideologies, power relations, sustainability...

  16. Critical Virtue Ethics

    Directory of Open Access Journals (Sweden)

    Jochen Schmidt

    2014-06-01

    Full Text Available Since the publication of Anscombe’s famous paper “Modern Moral Philosophy” (1958, virtue ethics has become a matter of discussion among scholars. At least four charges have been raised against virtue ethics, one of which is the charge of promoting undue enthusiasm regarding the moral fitness of human beings. This article explores the limits of virtue ethics with regard to the frailty of human virtuousness. After giving a report of the charges raised against virtue ethics from the perspective of empirical ethics, the author presents the idea of what he would like to call critical virtue ethics as seen by three Lutheran thinkers: Immanuel Kant, Friedrich Nietzsche and Martin Luther himself. He will demonstrate that the empirical contestation of virtue ethics shows a remarkable resemblance to insights found in Luther, Kant and Nietzsche. And finally, the writer draws tentative conclusions about the future of critical virtue ethics.

  17. Criticality in Neuronal Networks

    Science.gov (United States)

    Friedman, Nir; Ito, Shinya; Brinkman, Braden A. W.; Shimono, Masanori; Deville, R. E. Lee; Beggs, John M.; Dahmen, Karin A.; Butler, Tom C.

    2012-02-01

    In recent years, experiments detecting the electrical firing patterns in slices of in vitro brain tissue have been analyzed to suggest the presence of scale invariance and possibly criticality in the brain. Much of the work done however has been limited in two ways: 1) the data collected is from local field potentials that do not represent the firing of individual neurons; 2) the analysis has been primarily limited to histograms. In our work we examine data based on the firing of individual neurons (spike data), and greatly extend the analysis by considering shape collapse and exponents. Our results strongly suggest that the brain operates near a tuned critical point of a highly distinctive universality class.

  18. Snow loads in a changing climate: new risks?

    Directory of Open Access Journals (Sweden)

    U. Strasser

    2008-01-01

    Full Text Available In January/February 2006, heavy snowfalls in Bavaria (Germany lead to a series of infrastructural damage of catastrophic nature. Since on many collapsed roofs the total snow load was not exceptional, serious engineering deficiencies in roof construction and a sudden rise in the total snow load were considered to be the trigger of the events. An analysis of the then meteorological conditions reveals, that the early winter of 2005/2006 was characterised by an exceptional continuous snow cover, temperatures remained around the freezing point and no significant snowmelt was evident. The frequent freezing/thawing cycles were followed by a general compaction of the snow load. This resulted in a re-distribution and a new concentration of the snow load on specific locations on roofs. With respect to climate change, the question arises as to whether the risks relating to snow loads will increase. The future probability of a continuous snow cover occurrence with frequent freezing/thawing cycles will probably decline due to predicted higher temperatures. However, where temperatures remain low, an increase in winter precipitation will result in increased snow loads. Furthermore, the variability of extremes is predicted to increase. If heavy snowfall events are more frequent, the risk of a trigger event will likely increase. Finally, an attempt will be made here in this paper to outline a concept for an operational warning system for the Bavarian region. This system envisages to predict the development and risk of critical snow loads for a 3-day time period, utilising a combination of climate and snow modelling data and using this together with a snow pillow device (located on roofs and the results of which.

  19. Critical experiments on enriched uranium graphite moderated cores

    International Nuclear Information System (INIS)

    Kaneko, Yoshihiko; Akino, Fujiyoshi; Kitadate, Kenji; Kurokawa, Ryosuke

    1978-07-01

    A variety of 20 % enriched uranium loaded and graphite-moderated cores consisting of the different lattice cells in a wide range of the carbon to uranium atomic ratio have been built at Semi-Homogeneous Critical Experimental Assembly (SHE) to perform the critical experiments systematically. In the present report, the experimental results for homogeneously or heterogeneously fuel loaded cores and for simulation core of the experimental reactor for a multi-purpose high temperature reactor are filed so as to be utilized for evaluating the accuracy of core design calculation for the experimental reactor. The filed experimental data are composed of critical masses of uranium, kinetic parameters, reactivity worths of the experimental control rods and power distributions in the cores with those rods. Theoretical analyses are made for the experimental data by adopting a simple ''homogenized cylindrical core model'' using the nuclear data of ENDF/B-III, which treats the neutron behaviour after smearing the lattice cell structure. It is made clear from a comparison between the measurement and the calculation that the group constants and fundamental methods of calculations, based on this theoretical model, are valid for the homogeneously fuel loaded cores, but not for both of the heterogeneously fuel loaded cores and the core for simulation of the experimental reactor. Then, it is pointed out that consideration to semi-homogeneous property of the lattice cells for reactor neutrons is essential for high temperature graphite-moderated reactors using dispersion fuel elements of graphite and uranium. (author)

  20. electrical load survey electrical load survey and forecast

    African Journals Online (AJOL)

    eobe

    scattered nature of the area and low load factor. In this ... employment and allow decentralized production of the ... and viable concept from energy production and .... VII Yr. ×. kWh. VIII Yr. ×. kWh. IX Yr. ×. kWh. X Yr. ×. kWh. 1. Residential. 147.

  1. The critical catastrophe revisited

    International Nuclear Information System (INIS)

    De Mulatier, Clélia; Rosso, Alberto; Dumonteil, Eric; Zoia, Andrea

    2015-01-01

    The neutron population in a prototype model of nuclear reactor can be described in terms of a collection of particles confined in a box and undergoing three key random mechanisms: diffusion, reproduction due to fissions, and death due to absorption events. When the reactor is operated at the critical point, and fissions are exactly compensated by absorptions, the whole neutron population might in principle go to extinction because of the wild fluctuations induced by births and deaths. This phenomenon, which has been named critical catastrophe, is nonetheless never observed in practice: feedback mechanisms acting on the total population, such as human intervention, have a stabilizing effect. In this work, we revisit the critical catastrophe by investigating the spatial behaviour of the fluctuations in a confined geometry. When the system is free to evolve, the neutrons may display a wild patchiness (clustering). On the contrary, imposing a population control on the total population acts also against the local fluctuations, and may thus inhibit the spatial clustering. The effectiveness of population control in quenching spatial fluctuations will be shown to depend on the competition between the mixing time of the neutrons (i.e. the average time taken for a particle to explore the finite viable space) and the extinction time

  2. Relative Critical Points

    Directory of Open Access Journals (Sweden)

    Debra Lewis

    2013-05-01

    Full Text Available Relative equilibria of Lagrangian and Hamiltonian systems with symmetry are critical points of appropriate scalar functions parametrized by the Lie algebra (or its dual of the symmetry group. Setting aside the structures – symplectic, Poisson, or variational – generating dynamical systems from such functions highlights the common features of their construction and analysis, and supports the construction of analogous functions in non-Hamiltonian settings. If the symmetry group is nonabelian, the functions are invariant only with respect to the isotropy subgroup of the given parameter value. Replacing the parametrized family of functions with a single function on the product manifold and extending the action using the (coadjoint action on the algebra or its dual yields a fully invariant function. An invariant map can be used to reverse the usual perspective: rather than selecting a parametrized family of functions and finding their critical points, conditions under which functions will be critical on specific orbits, typically distinguished by isotropy class, can be derived. This strategy is illustrated using several well-known mechanical systems – the Lagrange top, the double spherical pendulum, the free rigid body, and the Riemann ellipsoids – and generalizations of these systems.

  3. Plant critical concept

    International Nuclear Information System (INIS)

    O'Regan, P.J.

    1996-01-01

    The objective of the effort summarized in this paper is to support O and M cost reduction efforts by focusing resources on components and processes critical to plant performance. This effort will identify where resources on nonplant critical components and processes can be reduced or eliminated. This method will use a functional assessment as the basis for component-specific evaluations and ranking. This effort consists of two stages conducted in series. The first stage is to deterministically identify that set of plant components that are relevant from a plant performance perspective (i.e., safety, economics, reliability). The second stage probabilistically ranks that set of plant components from an importance perspective, where importance pertains to the particular application and is probabilistically weighted. The results of a pilot study identified that only a relatively small set of components are truly critical from an integrated plant performance perspective. These results are consistent with work being conducted at other nuclear power plants, as well as other commercial facilities. Initial implementation of this effort is estimated to reduce O and M costs on the order of $1 million per year. Subsequent applications are anticipated to increase that savings to $4--$5 million per year

  4. Criticality alarm device

    International Nuclear Information System (INIS)

    Sasaki, Takashi.

    1995-01-01

    In a critical alarm device comprising an n-number of radiation detectors and a 2/3 logic module, the 2/3 logic module comprises a rectifier inputting an output of an AC power and outputting it as a full wave-rectified, DC voltage, an analog/digital converter inputting the output from the rectifier, putting it to analog/digital conversion and continuously storing it into a memory, a latch circuit inputting critical signals from the 2/3 logic and holding them and outputting latch signals, and a means for outputting timing signals for data storage to a memory based on clocks at a predetermined period and outputting timing signals for stopping the data storage to the memory after passing a predetermined period from the inputting time point if the latch signals are inputted from the latch circuit. Then, judgement whether the generation of criticality is caused by an actual radiation detection or by noises from the power source is enabled, to provide extremely high reliability. (N.H.)

  5. RF Loads for Energy Recovery

    CERN Document Server

    Federmann, S; Caspers, F

    2012-01-01

    Different conceptional designs for RF high power loads are presented. One concept implies the use of solid state rectifier modules for direct RF to DC conversion with efficiencies beyond 80%. In addition, robust metallic low-Q resonant structures, capable of operating at high temperatures (>150 ◦C) are discussed. Another design deals with a very high temperature (up to 800 ◦C) air cooled load using a ceramic foam block inside a metal enclosure. This porous ceramic block is the microwave absorber and is not brazed to the metallic enclosure.

  6. SPEAR 2 RF SYSTEM LOADS

    International Nuclear Information System (INIS)

    2002-01-01

    The design and performance of higher order mode (HOM) dampers for the SPEAR 2 RF system is presented. The SPEAR beam had experienced occasional periods of instability due to transverse oscillations which were driven by HOMs in the RF cavities. A substantial fraction of this RF energy was coupled out of the cavity into the waveguide connecting the cavity to the klystron. This waveguide was modified by adding a stub of smaller cross section, terminated by a ferrite tile load, to the system. Design considerations of the load, and its effect on HOMs and beam stability will be discussed

  7. Method for loading resin beds

    International Nuclear Information System (INIS)

    Notz, K.J.; Rainey, R.H.; Greene, C.W.; Shockley, W.E.

    1978-01-01

    An improved method of preparing nuclear reactor fuel by carbonizing a uranium loaded cation exchange resin provided by contacting a H+ loaded resin with a uranyl nitrate solution deficient in nitrate, comprises providing the nitrate deficient solution by a method comprising the steps of reacting in a reaction zone maintained between about 145 to 200 0 C, a first aqueous component comprising a uranyl nitrate solution having a boiling point of at least 145 0 C with a second aqueous component to provide a gaseous phase containing HNO 3 and a reaction product comprising an aqueous uranyl nitrate solution deficient in nitrate

  8. Nuclear fuel pellet loading apparatus

    International Nuclear Information System (INIS)

    Gerkey, K.S.

    1979-01-01

    An automatic apparatus for loading a predetermined amount of nuclear fuel pellets into a nuclear fuel element to be used in a nuclear reactor is described. The apparatus consists of a vibratory bed capable of supporting corrugated trays containing rows of nuclear fuel pellets and arranged in alignment with the open ends of several nuclear fuel elements. A sweep mechanism is arranged above the trays and serves to sweep the rows of fuel pellets onto the vibratory bed and into the fuel element. A length detecting system, in conjunction with a pellet stopping mechanism, is also provided to assure that a predetermined amount of nuclear fuel pellets are loaded into each fuel element

  9. Controlled delamination of metal films by hydrogen loading

    Energy Technology Data Exchange (ETDEWEB)

    Nikitin, Eugen

    2008-11-18

    n this work we quantitatively determine the adhesion energy between metal films and their substrates. Therefore a new controlled buckling technique is established, applying the strong compressive in-plane stress that results in thin films clamped on rigid substrates during hydrogen loading. When the elastic energy stored in the H-loaded thin film exceeds the adhesion energy between film and substrate, delamination occurs. At the onset of delamination, a critical hydrogen concentration, a critical stress value and a critical bending of the substrate are present, which are quantitative measures for the adhesion energy and permit its calculation. As the critical values are determined at the onset of delamination, plastic deformation is negligible, which denies the quantitative determination of adhesion energies in conventional test setups. In multilayer-systems, adhesion energies between substrates and films that hardly absorb hydrogen can be measured by the controlled buckling technique, when the films of interest are coated with hydrogen absorbing films (active layer). The measurements are performed easily and can be repeated under the same test conditions, while variables such as the thickness of the coating materials or the boundary surface structure can be varied and optimized. In this work the adhesion energies of different materials on polycarbonate and niobium on sapphire are investigated. (orig.)

  10. 46 CFR 169.689 - Demand loads.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Demand loads. 169.689 Section 169.689 Shipping COAST... Electrical Electrical Installations on Vessels of 100 Gross Tons and Over § 169.689 Demand loads. Demand loads must meet § 111.60-7 of this chapter except that smaller demand loads for motor feeders are...

  11. TIME LOAD UPON STUDENTS IN PRIMARY EDUCATION

    Directory of Open Access Journals (Sweden)

    Borce Kostov

    2016-12-01

    Full Text Available Time load upon students is a central issue in the context of the overall load placed upon students. Most authors dealing with the issue of load upon students mainly approach this issue from the aspect of the time the students need to respond to the requirements posed by the school and otherwise concerning school. Such load is called time load. In our research, we investigated exactly this kind of time load placed upon students in the nine-year primary education in Macedonia. The main goal of our research was getting insight what is the students’ time load like and how big it is.

  12. Critical stresses in pintle, weldment and top head of nuclear waste container

    International Nuclear Information System (INIS)

    Ladkany, S.G.; Kniss, B.R.

    1992-01-01

    Critical stresses in the pintle, the weldment, and the top heads (flat and curved), of a high level nuclear waste container are evaluated under an annular loading. This loading is three times larger than the expected normal operating load. Results show that the shape and the thickness of the pintle and the top head, along with the thickness of the weldment, substantially affect the magnitude of the critical stresses and distortions in the various components (i.e. pintle, shell, and heads) when they are supporting a load. Stiffer top heads and pintles and larger weldment sizes reduce the critical stresses in all welded joints. Various shapes of curved top heads were investigated. In this paper an ASME flanged and dished top head, which has the same thickness as the canister, is analyzed

  13. Nuclear criticality assessment of LEU and HEU fuel element storage

    International Nuclear Information System (INIS)

    Pond, R.B.; Matos, J.E.

    1984-01-01

    Criticality aspects of storing LEU (20%) and HEU (93%) fuel elements have been evaluated as a function of 235 U loading, element geometry, and fuel type. Silicide, oxide, and aluminide fuel types have been evaluated ranging in 235 U loading from 180 to 620 g per element and from 16 to 23 plates per element. Storage geometry considerations have been evaluated for fuel element separations ranging from closely packed formations to spacings of several centimeters between elements. Data are presented in a form in which interpolations may be made to estimate the eigenvalue of any fuel element storage configuration that is within the range of the data. (author)

  14. Handling load with less stress

    NARCIS (Netherlands)

    Bansal, N.; Gamarnik, D.

    2006-01-01

    We study how the average performance of a system degrades as the load nears its peak capacity. We restrict our attention to the performance measures of average sojourn time and the large deviation rates of buffer overflow probabilities. We first show that for certain queueing systems, the average

  15. Robust Multimodal Cognitive Load Measurement

    Science.gov (United States)

    2014-03-26

    75th percentiles. Results and Discussion: As an example, Figure 2 shows the median of the extracted HRE from the frontal channels in scale 5, for...the extracted HRE are able to distinguish the seven task loads better with q closer to 1, as it consistently reveals a decreasing median with

  16. Wind Structure and Wind Loading

    DEFF Research Database (Denmark)

    Brorsen, Michael

    The purpose of this note is to provide a short description of wind, i.e. of the flow in the atmosphere of the Earth and the loading caused by wind on structures. The description comprises: causes to the generation of windhe interaction between wind and the surface of the Earthhe stochastic nature...

  17. Numerical prediction of slamming loads

    DEFF Research Database (Denmark)

    Seng, Sopheak; Jensen, Jørgen J; Pedersen, Preben T

    2012-01-01

    It is important to include the contribution of the slamming-induced response in the structural design of large vessels with a significant bow flare. At the same time it is a challenge to develop rational tools to determine the slamming-induced loads and the prediction of their occurrence. Today i...

  18. Amelioration of the cooling load based chiller sequencing control

    International Nuclear Information System (INIS)

    Huang, Sen; Zuo, Wangda; Sohn, Michael D.

    2016-01-01

    Highlights: • We developed a new approach for the optimal load distribution for chillers. • We proposed a new approach to optimize the number of operating chillers. • We provided a holistic solution to address chiller sequencing control problems. - Abstract: Cooling Load based Control (CLC) for the chiller sequencing is a commonly used control strategy for multiple-chiller plants. To improve the energy efficiency of these chiller plants, researchers proposed various CLC optimization approaches, which can be divided into two groups: studies to optimize the load distribution and studies to identify the optimal number of operating chillers. However, both groups have their own deficiencies and do not consider the impact of each other. This paper aims to improve the CLC by proposing three new approaches. The first optimizes the load distribution by adjusting the critical points for the chiller staging, which is easier to be implemented than existing approaches. In addition, by considering the impact of the load distribution on the cooling tower energy consumption and the pump energy consumption, this approach can achieve a better energy saving. The second optimizes the number of operating chillers by modulating the critical points and the condenser water set point in order to achieve the minimal energy consumption of the entire chiller plant that may not be guaranteed by existing approaches. The third combines the first two approaches to provide a holistic solution. The proposed three approaches were evaluated via a case study. The results show that the total energy consumption saving for the studied chiller plant is 0.5%, 5.3% and 5.6% by the three approaches, respectively. An energy saving of 4.9–11.8% can be achieved for the chillers at the cost of more energy consumption by the cooling towers (increases of 5.8–43.8%). The pumps’ energy saving varies from −8.6% to 2.0%, depending on the approach.

  19. Prioritized rule based load management technique for residential building powered by PV/battery system

    Directory of Open Access Journals (Sweden)

    T.R. Ayodele

    2017-06-01

    Full Text Available In recent years, Solar Photovoltaic (PV system has presented itself as one of the main solutions to the electricity poverty plaguing the majority of buildings in rural communities with solar energy potential. However, the stochasticity associated with solar PV power output owing to vagaries in weather conditions is a major challenge in the deployment of the systems. This study investigates approach for maximizing the benefits of a Stand-Alone Photovoltaic-Battery (SAPVB system via techniques that provide for optimum energy gleaning and management. A rule-based load management scheme is developed and tested for a residential building. The approach allows load prioritizing and shifting based on certain rules. To achieve this, the residential loads are classified into Critical Loads (CLs and Uncritical Loads (ULs. The CLs are given higher priority and therefore are allowed to operate at their scheduled time while the ULs are of less priority, hence can be shifted to a time where there is enough electric power generation from the PV arrays rather than the loads being operated at the time period set by the user. Four scenarios were created to give insight into the applicability of the proposed rule based load management scheme. The result revealed that when the load management technique is not utilized as in the case of scenario 1 (Base case, the percentage satisfaction of the critical and uncritical loads by the PV system are 49.8% and 23.7%. However with the implementation of the load management scheme in scenarios 2, 3 and 4, the percentage satisfaction of the loads (CLs, ULs are (93.8%, 74.2%, (90.9%, 70.1% and (87.2%, 65.4% for scenarios 2, 3 and 4, respectively.

  20. Criticality accident alarm system

    International Nuclear Information System (INIS)

    Malenfant, R.E.

    1991-01-01

    The American National Standard ANSI/ANS-8.3-1986, Criticality Accident Alarm System provides guidance for the establishment and maintenance of an alarm system to initiate personnel evacuation in the event of inadvertent criticality. In addition to identifying the physical features of the components of the system, the characteristics of accidents of concern are carefully delineated. Unfortunately, this ANSI Standard has led to considerable confusion in interpretation, and there is evidence that the ''minimum accident of concern'' may not be appropriate. Furthermore, although intended as a guide, the provisions of the standard are being rigorously applied, sometimes with interpretations that are not consistent. Although the standard is clear in the use of absorbed dose in free air of 20 rad, at least one installation has interpreted the requirement to apply to dose in soft tissue. The standard is also clear in specifying the response to both neutrons and gamma rays. An assembly of uranyl fluoride enriched to 5% 235 U was operated to simulate a potential accident. The dose, delivered in a free run excursion 2 m from the surface of the vessel, was greater than 500 rad, without ever exceeding a rate of 20 rad/min, which is the set point for activating an alarm that meets the standard. The presence of an alarm system would not have prevented any of the five major accidents in chemical operations nor is it absolutely certain that the alarms were solely responsible for reducing personnel exposures following the accident. Nevertheless, criticality alarm systems are now the subject of great effort and expense. 13 refs