Coastal trapped waves in the southern Caspian Sea

Previous studies reported coastal trapped waves (CTWs) in the Caspian Sea (CS). This study deals with the generation mechanisms, the temporal and spatial variability of CTWs in this area, and their transformations during propagation from the origin to the destination using recent measurements and high-resolution numerical simulations. CTWs are observed at all stations with periods of 2–6 days after northerly storms. The Absheron Peninsula, old Sefidrud delta, and Nur coasts were identified as the CTWs prone regions. The generation of CTWs in these locations was confirmed using numerical experiments. The propagation away from the generating location of CTWs was analyzed using a representative real wind storm. In the west part of the CS, the generation mechanism of CTWs is mainly similar to the barotropic Kelvin waves; in contrast, it is similar to the continental shelf waves in the southern shelves. The results can be used to study the contribution of generated CTWs to the transport of sediment and biological materials in all large lakes.     

Hysteresis loops of carbon fiber-reinforced ceramic-matrix composites with different fiber preforms

The hysteresis loops of C/SiC ceramic-matrix composites (CMCs) with different fiber preforms, i.e., unidirectional, cross-ply, 2D and 2.5D woven, 3D braided, and 3D needled at room temperature have been investigated. Based on fiber slipping mechanisms, the hysteresis loops models considering different interface slip cases have been developed. The effects of fiber volume fraction, matrix cracking density, interface shear stress, interface debonded energy, and fibers failure on hysteresis loops, hysteresis dissipated energy, hysteresis width, and hysteresis modulus have been analyzed. An effective coefficient of fiber volume fraction along the loading direction (ECFL) was introduced to describe fiber preforms. The hysteresis loops, hysteresis dissipated energy and hysteresis modulus of unidirectional, cross-ply, 2D and 2.5D woven, 3D braided and 3D needled C/SiC composites have been predicted.     

Performance evaluation of spaceborne cryocooler micro-vibration isolation system employing pseudoelastic SMA mesh washer

A spaceborne cryocooler produces undesirable micro-vibration disturbances during its on-orbit operation, which is one of the main sources of degradation of the image quality of high-resolution observation satellites. Therefore, to comply with the strict mission requirement for the acquisition of high-quality images, micro-vibration disturbances induced by cryocooler operation need to be isolated. In this study, we proposed a spaceborne cryocooler micro-vibration isolator that employs a pseudoelastic shape memory alloy (SMA) mesh washer, which guarantees vibration isolation performance in a severe launch vibration environment while effectively isolating the micro-vibrations from the cryocooler on-orbit. Basic characteristics of the cryocooler assembly integrated with the proposed isolators were measured through static tests and free vibration tests. The effectiveness of the isolator design was demonstrated by the micro-vibration measurement tests under qualification temperature limits.     

Interval‐valued probabilistic linguistic term sets in multi‐criteria group decision making

The theory of probabilistic linguistic term sets (PLTSs) is very useful in objectively dealing with the multi‐criteria group decision making (MCGDM) problems in which there is hesitancy in providing linguistic assessments; and PLTSs allow experts to express their preferences on one linguistic term over another. In order to reflect the uncertainty and inconsistency of decision‐makers and handle incomplete linguistic information, we propose a new PLTS called interval‐valued probabilistic linguistic term set (IVPLTS). In addition, the existing approaches associated with PLTSs are limited or highly complex in real applications. Therefore, new operations, comparison laws, and aggregation operators are developed for IVPLTS. Furthermore, we establish an efficient framework for MCGDM problems based on the proposed comparison method and the fuzzy preference relation. Then we apply it to a real‐life case under linguistic environment. The extended TOPSIS methods combined with PLTSs by using different operational laws are also included for comparison. The final results demonstrate the efficiency and practicality of the new framework.     

Predicting test data of aluminum honeycomb sandwich board based on volterra adaptive filters

Random vibration test was done on aluminum honeycomb sandwich board.The result suggested that chaotic behavior is found in the test data.The Volterra expression can not be gained from the input and output data directly in this paper.The state space reconstruction was used to convert the system observed data into the quasi-input/output pairs,and the second-order Volterra adaptive filter was used to predict the test data.It is shown that combining the state space reconstruction with the Volterra adaptive filter,these chaotic series could be accurately predicted.     

Web classification of conceptual entities using co-training

Social networking websites, which profile objects with predefined attributes and their relationships, often rely heavily on their users to contribute the required information. We, however, have observed that many web pages are actually created collectively according to the composition of some physical or abstract entity, e.g., company, people, and event. Furthermore, users often like to organize pages into conceptual categories for better search and retrieval, making it feasible to extract relevant attributes and relationships from the web. Given a set of entities each consisting of a set of web pages, we name the task of assigning pages to the corresponding conceptual categories conceptual web classification. To address this, we propose an entity-based co-training (EcT) algorithm which learns from the unlabeled examples to boost its performance. Different from existing co-training algorithms, EcT has taken into account the entity semantics hidden in web pages and requires no prior knowledge about the underlying class distribution which is crucial in standard co-training algorithms used in web classification. In our experiments, we evaluated EcT, standard co-training, and other three non co-training learning methods on Conf-425 dataset. Both EcT and co-training performed well when compared to the baseline methods that required large amount of training examples.     

Experimental study on flicker emissions by photovoltaic systems on highly cloudy region: A case study in Malaysia

Photovoltaic (PV) systems are the most promising renewable energy sources in Malaysia because of its location being around the equatorial region where sunlight is available throughout the year. However, the country is warm and surrounded by the South China Sea and Malacca Straits. A large amount of clouds is created and passed over the region. The impacts of the passing clouds on the PV power outputs and voltage magnitude have to be studied thoroughly. Therefore, an experimental low-voltage network integrated with a PV system is set up. The experimental results show that the passing clouds result in the frequent and rapid fluctuations of PV power outputs, hence producing a large amount of flickers to the distribution networks. Some of the flickers are actually greater than the statutory limits. To mitigate this power quality issue, a dynamic load controller is proposed to be the solution because its components are cheap. The load controller is made of a number of 200 W power resistors and solid-state relays. A central controller switches the resistors on and off very rapidly based on the fluctuations of the network voltage. The experimental results show that the dynamic load controller is able to reduce the flickers effectively on the distribution networks. The studies and solution presented in this paper are very valuable to different parties, such as the government, policy makers, utility companies and owners of the PV systems, in order to ensure an effective growth of the PV systems without compromising the quality of electricity supply to the customers.     

Multiphysics modeling approach for micro electro–thermo–mechanical actuator: Failure mechanisms coupled analysis

The lifetime of micro electro–thermo–mechanical actuators with complex electro–thermo–mechanical coupling mechanisms can be decreased significantly due to unexpected failure events. Even more serious is the fact that various failures are tightly coupled due to micro-size and multi-physics effects. Interrelation between performance and potential failures should be established to predict reliability of actuators and improve their design. Thus, a multiphysics modeling approach is proposed to evaluate such interactive effects of failure mechanisms on actuators, where potential failures are pre-analyzed via FMMEA (Failure Modes, Mechanisms, and Effects Analysis) tool for guiding the electro–thermo–mechanical-reliability modeling process. Peak values of temperature, thermal stresses/strains and tip deflection are estimated as indicators for various failure modes and factors (e.g. residual stresses, thermal fatigue, electrical overstress, plastic deformation and parameter variations). Compared with analytical solutions and experimental data, the obtained simulation results were found suitable for coupled performance and reliability analysis of micro actuators and assessment of their design.     

Reconfigurable address generator for multi-standard interleaver

This paper presents low-complex and novel techniques for designing reconfigurable architectures for multi-standard address generator and interleaver. The emphasis of this work is on hardware re-use, but it also focuses on optimizing the hardware to support multiple standards. A low-cost reconfigurable architecture for address generator and interleaver is proposed which operates in WLAN (802.11a/b/g and 802.11n), WiMAX (802.16e) and 3GPP LTE standards. A simple algorithm and a reconfigurable architecture that eliminates the computationally intricate mod function for LTE, and floor as well as mod function for WLAN/WiMAX, are proposed to reduce the hardware cost as well as implementation complexity. Novel architectures are also proposed to select the increment values for 16-QAM and 64-QAM schemes. A unique configurable subtracting sub-block for each modulation scheme is also presented. Software simulation is carried out to authenticate the functionality of the algorithm. The proposed reconfigurable architectures are realized on FPGA and tested on board. Synthesis results on Spartan-3 FPGA display 66% reduction in FPGA resource utilization and 74% increase in operating frequency compared to the cited address generators. Implementation results on Kintex UltraScale FPGA display a reduction of 34% in resource utilization and 20% in total on-chip power compared to the cited interleavers. This design is also implemented using 45 nm CMOS standard cell technology, and ASIC synthesis results of the reconfigurable address generator exhibit 76.4% improvement in data rate and 52.23% decrease in latency compared to the state-of-the-art address generators. The proposed multimode interleaver also exhibit 60.28% reduction in hardware complexity.     

Growth or penetration of Salmonella into citrus fruit is not facilitated by natural-light labels

In natural-light labeling of fruits and vegetables, the desired information is etched onto the produce surface using a low-energy carbon dioxide laser beam (10,600 nm). Etched characters are formed by surface depressions in the epidermis that may facilitate entrance of decay and pathogenic organisms. The objective of this study was to determine the effects of natural-light labeling and different postharvest treatments on Salmonella populations' ability to survive/grow and penetrate into citrus fruit. A five-strain cocktail of Salmonella was spot inoculated onto Valencia orange in different application sequences with wax and natural-light etching. Samples were stored at 10, 26 °C, or combinations of both, for up to 42 days. Etched peels and corresponding juices were extracted from whole oranges following storage and enumerated for Salmonella. No set of conditions involving natural-light labeling promoted the growth of Salmonella on the fruit surface or resulted in the detection of Salmonella from the juice of sound fruit. Survival of Salmonella populations on the peel surface did not differ between any of the treatment and control samples. In all cases, Salmonella declined between 1.5 and 3.0 log CFU/orange after 30 days, with faster decline noted at 10 °C. Based on the data obtained from all treatments and under conditions extremely unfavorable and unrealistic in terms of fruit storage, natural-light labeling citrus fruit peels and subsequent waxing in any order did not allow for the growth or influence the natural decline of Salmonella populations on citrus fruit surfaces, or movement into juices, as compared to controls.