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Cameron Novak Michael Keller Theresa Meza James McKinnies Erik Espinosa Kristie Calhoun 《Fire Technology》2018,54(4):921-941
In the past, some fire investigators have determined the cause of a fire to be electrical in nature based, in part, on the presence of an electrical cord or cable found beneath a furniture leg or a cable wedged tightly under a staple. While fires resulting from these events are possible, the mechanisms that lead to these failures are poorly understood. In this paper, the results of four research projects are presented. The first three projects focused on the creation of a pinched cord failure under various current loads and pressures. In the last project, a typical nonmetallic-sheathed cable was damaged and then installed with an overdriven staple over the damaged location. In all tests, the cords and cables were subjected to current loads varying between 100 and 250% of the rated ampacity. The failure rate of pinched cords was approximately 1%, but required the use of overloaded circuits and pre-existing damage or special orientation of the cord under test. A critical factor worth considering with these failures, which is often not accounted for, is time. These failures may take weeks, months, or years to occur under normal conditions, although some investigators may assume they develop nearly instantaneously. The conditions of the circuit are also important, as the only way a failure developed in these tests was by operating the circuits in excess of their rated parameters. 相似文献
24.
Since the 2007/08 food price crisis there has been a proliferation of multi-stakeholder processes (MSPs) devoted to bringing diverse perspectives together to inform and improve food security policy. While much of the literature highlights the positive contributions to be gained from an opening-up of traditionally state-led processes, there is a strong critique emerging to show that, in many instances, MSPs have de-politicizing effects. In this paper, we scrutinize MSPs in relation to de-politicization. We argue that re-building sustainable and just food systems requires alternative visions that can best be made visible through politicized policy processes. Focusing on three key conditions of politicization, we examine the UN Committee on World Food Security as a MSP where we see a process of politicization playing out through the endorsement of the ‘most-affected’ principle, which is in turn being actively contested by traditionally powerful actors. We conclude that there is a need to implement and reinforce mechanisms that deliberately politicize participation in MSPs, notably by clearly distinguishing between states and other stakeholders, as well as between categories of non-state actors. 相似文献
25.
Yingying Shi Lijun Luo Yefei Zhang Yu Chen Shan Wang Lingxin Li Yanju Long Fengzhi Jiang 《Journal of Materials Science》2018,53(2):1049-1064
The porous platelet-shaped α-Bi2O3 photocatalyst was successfully synthesized by a novel hydrothermal–calcination method assisted with ethylenediamine and polyvinylpyrrolidone. The physical and chemical properties of α-Bi2O3 photocatalyst were characterized based on XRD, XPS, SEM, TEM, EDS, UV–Vis DRS, and PL techniques. The influence of preparation conditions on the formation of α-Bi2O3 photocatalyst was investigated, and the effect of catalyst dosage and pH value on the EE2 removal rate was also investigated. The synthesized porous platelet-shaped α-Bi2O3 photocatalyst exhibited excellent photocatalytic activity for 17α-ethynylestradiol (EE2), and 97.8% of EE2 was removed after 75 min of visible light irradiation using α-Bi2O3 as photocatalyst. The reaction rate constant over the porous platelet-shaped α-Bi2O3 photocatalyst was 11.6 and 11.4 times of that of traditional α-Bi2O3 and N-TiO2, respectively. The possible photocatalytic mechanism has been discussed on the basis of the theoretical calculation and the experimental results. The porous platelet-shaped α-Bi2O3 was a stable and efficient photocatalyst, proving that it is a promising photocatalyst. 相似文献
26.
Erwin Krauskopf 《Scientometrics》2018,116(3):1805-1815
Researchers continually strive to communicate their findings to peers, hoping to receive recognition for their contribution in a not-so-distant future. The prevailing idea of “publish or perish” becomes imperative when researchers are applying for competitive grants or academic promotions. Choosing a suitable journal has become an important issue as thousands of journals are available. One of the aspects considered by researchers is the journal’s indexation status. Scopus continuously evaluates journals submitted by publishers for indexation, and later, to verify if quality is maintained. During this re-evaluation process, some publication concerns may be raised at journal or publisher level. Consequently, Scopus periodically issues a list of discontinued journals. However, not all journals update their websites in order to inform readers that they have been discontinued. This study shows that 56 journals that were discontinued in 2016 currently affirm on their websites that they are indexed by Scopus. In addition, another 20 journals discontinued in 2016, which do not specifically state that they are indexed by Scopus, include a widget from SCImago that may generate confusion about their current indexing situation. For some journals it seems that the emphasis is placed more on the publishing end of the business than the dissemination of research findings. This study shows that regular updates are among the responsibilities that editorial teams must maintain to ensure the quality and accuracy of the information posted on journal websites. 相似文献
27.
Pooyan Ayar Fernando Moreno-Navarro Miguel Sol-Sánchez Mª Carmen Rubio-Gámez 《Materials and Structures》2018,51(1):25
Recovery capability of bituminous materials plays a significant role in the development of new technologies for extending the service life of asphalt pavements. This capability originates from various phenomena such as thixotropy, cooling, relaxation of hardening, or healing. However, their real effect on mechanical response is not clear. This article aims to investigate how rest periods (RPs) available between traffic loads can contribute to the damage recovery of bituminous materials. For this purpose, different types and durations of RPs were applied during the laboratory evaluation of fatigue resistance of these materials using the University of Granada Fatigue Asphalt Cracking Test method. The results indicate that the addition of RPs to the loading regime could lead to an extension in the fatigue life of bituminous materials. Additionally, an increase in the RP duration showed a positive impact on the resistance of the materials against cyclic loading. Nonetheless, these benefits are not only related to the recovery of lost properties during RPs, but also a growth in the amount of plastic deformations as a result of the applying RPs could delay the appearance of damages (i.e. cracking). Consequently, the bituminous material can tolerate a higher number of load cycles during fatigue test. 相似文献
28.
Giulio Costa Marco Montemurro Jérôme Pailhès 《International Journal of Mechanics and Materials in Design》2018,14(4):669-696
In this paper, the solid isotropic material with penalisation (SIMP) method for topology optimisation of 2D problems is reformulated in the non-uniform rational BSpline (NURBS) framework. This choice implies several advantages, such as the definition of an implicit filter zone and the possibility for the designer to get a geometric entity at the end of the optimisation process. Therefore, important facilities are provided in CAD postprocessing phases in order to retrieve a consistent and well connected final topology. The effect of the main NURBS parameters (degrees, control points, weights and knot-vector components) on the final optimum topology is investigated. Classic geometric constraints, as the minimum and maximum member size, have been integrated and reformulated according to the NURBS formalism. Furthermore, a new constraint on the local curvature radius has been developed thanks to the NURBS formalism and properties. The effectiveness and the robustness of the proposed method are tested and proven through some benchmarks taken from literature and the results are compared with those provided by the classical SIMP approach. 相似文献
29.
Elias Martinez Hernandez Kok Siew Ng 《Clean Technologies and Environmental Policy》2018,20(7):1501-1514
Unlocking the potential and value of lignocellulosic residues is an important step in making biorefineries economically and environmentally promising. This calls for a holistic and systematic approach in designing sustainable industrial systems. In this work, biorefinery systems via biochemical route (acetone–butanol–ethanol or ABE system) and thermochemical route (gasification and mixed alcohols or GMA system) for converting corn stover into biofuels have been designed using a Sustainable Engineering Framework. The framework involves eight main steps: (1) design problem definition, (2) data collection, (3) process synthesis and simulation, (4) process integration, (5) resource recovery from residues, (6) utility system design, (7) economic and environmental modelling and (8) economic value and environmental impact margin analysis for decision making. Consideration of resource recovery from biorefinery waste streams has proven to be the key in making biorefineries self-sustaining and with low environmental impacts. Simultaneous economic and environmental feasibility assessment at the early stage of process design is highly envisaged. The cost of biofuel production in the ABE system has been found to be 49.2 US$/GJ and 69.9 US$/GJ in the GMA system. The greenhouse gas emissions are 46.2 g CO2-eq/GJ for ABE and 19.0 g CO2-eq/GJ for GMA, lower than gasoline (85 g CO2-eq/GJ). The GMA system is not economically compelling though with high environmental benefit, while the ABE system has shown to be both economically and environmentally feasible. 相似文献
30.
A. Basheer S. M. Tauseef Tasneem Abbasi S. A. Abbasi 《Journal of Failure Analysis and Prevention》2018,18(1):83-91
A new method, RIsk and DIstance Minimization in Process Units Siting (RIDIMPUS), is presented with which hazardous units can be sited in a chemical process facility in a manner that the risk of accidents involving the hazardous units as also the cost of spacing the units is minimized. To achieve this, safety and cost factors were modeled using various governing parameters and then expressions were designed to integrate the safety and the economic concerns to form model equations, inequalities and disjunctions. The resulting nonlinear programming model is solvable by using algorithms and solvers on any common desktop computer, thereby providing an optimal and prompt solution. 相似文献