6,804 research outputs found
Direct Observation of Long-Term Durability of Superconductivity in YBaCuO-AgO Composites
We report direct observation of long-term durability of superconductivity of
several YBaCuO-AgO composites that were first prepared and
studied almost 14 years ago [J. J. Lin {\it et al}., Jpn. J. Appl. Phys. {\bf
29}, 497 (1990)]. Remeasurements performed recently on both resistances and
magnetizations indicate a sharp critical transition temperature at 91 K. We
also find that such long-term environmental stability of high-temperature
superconductivity can only be achieved in YBaCuO with AgO
addition, but not with pure Ag addition.Comment: to be published in Jpn. J. Appl. Phy
An Exploration of Activities, Reasons, and Barriers of Using Social Media for Food Allergy Management
Managing food allergies can be overwhelming for affected individuals. Social media (SoMe) may serve as a platform for individuals with food allergies to access and share useful information. This study investigates SoMe use among adults with food allergies. Fifty individuals with food allergies answered a series of open-ended questions related to their SoMe use behaviors. The answers were used to develop an online anonymous survey, which was completed by 319 individuals with food allergies. Results indicate that SoMe users mainly use SoMe to gather updated information about food allergies and hear somebody else’s experiences and advices about food allergies. Lack of privacy, concerns about reliability of the information, and lack of efficiency were barriers to the use of SoMe. Those who were younger, had an allergic reaction in restaurants in the past, and who were newly diagnosed with food allergy were more likely to engage in SoMe use for food allergy related purposes. SoMe administrators may seek strategies to remove barriers and share information from credible resources to benefit those in need of such information
Physical Layer Security in Wireless Ad Hoc Networks Under A Hybrid Full-/Half-Duplex Receiver Deployment Strategy
This paper studies physical layer security in a wireless ad hoc network with
numerous legitimate transmitter-receiver pairs and eavesdroppers. A hybrid
full-/half-duplex receiver deployment strategy is proposed to secure legitimate
transmissions, by letting a fraction of legitimate receivers work in the
full-duplex (FD) mode sending jamming signals to confuse eavesdroppers upon
their information receptions, and letting the other receivers work in the
half-duplex mode just receiving their desired signals. The objective of this
paper is to choose properly the fraction of FD receivers for achieving the
optimal network security performance. Both accurate expressions and tractable
approximations for the connection outage probability and the secrecy outage
probability of an arbitrary legitimate link are derived, based on which the
area secure link number, network-wide secrecy throughput and network-wide
secrecy energy efficiency are optimized respectively. Various insights into the
optimal fraction are further developed and its closed-form expressions are also
derived under perfect self-interference cancellation or in a dense network. It
is concluded that the fraction of FD receivers triggers a non-trivial trade-off
between reliability and secrecy, and the proposed strategy can significantly
enhance the network security performance.Comment: Journal paper, double-column 12 pages, 9 figures, accepted by IEEE
Transactions on Wireless Communications, 201
Effect of Ceramic Dust as Partial Replacement of Cement on Lightweight Foamed Concrete
Disposal of waste into the landfill causes a severe impact on the environment. One of the waste products is ceramic waste. Ceramic waste has some excellent properties in its durability, hardness, and highly resistant to biological, chemical, and physical degradation forces. These excellent properties of the ceramic waste may make it suitable to be used in concrete. This study investigates the effect on the compressive strength of lightweight foamed concrete with different percentage of ceramic dust replacement level towards the cement and three different levels of water-cement ratio. 0%, 5%, 15%, and 25% of replacement level with 0.52, 0.56, and 0.60 water-cement ratios respectively for each replacement level was used as the parameter to investigate the fresh properties, and strength performance of lightweight foamed concrete. The stability and consistency of every mix are studied as well. From this study, it was observed that the incorporation of ceramic waste dust partially replaced the cement did not affect on the fresh properties of the foamed concrete. However, the compressive strength of foamed concrete affected by ceramic waste dust partially replaced the cement
A Comparative Study of Deep Learning Model and Simple Prediction Charts in Construction Noise Prediction
Construction noise monitoring is crucial to assess the impacts of construction noise on the workers and surroundings. However, the existing noise prediction methods are time-consuming in which required laborious work for the computation of noise levels. This study aims to assess the accuracy and reliability of deep learning model (DL) that adopted stochastic modelling and artificial neural network (ANN) in construction noise prediction. The artificial neural network was trained with the output of stochastic modelling. The outcome of noise level prediction using simple prediction chart (SPC) and DL model was discussed and compared to 3 case studies. The case studies were conducted at construction sites located in Semenyih, Selangor, Malaysia. The results of DL model showed high accuracy of predicted noise levels along with an absolute difference of less than 2.3 dBA. Besides, the predicted noise levels are reliable as the R-squared value is higher than 0.992. On that account, DL model is proved to be reliable and accurate in noise level prediction and it has the potential to be utilized as a managerial tool to monitor construction noise more effectively
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