Spaceborne radar measurement of wind velocity over the ocean-anoverview of the NSCAT scatterometer system

Scatterometry and scatterometer design issues are reviewed. The design of the NASA Scatterometer (NSCAT) to be flown on the Japanese ADEOS mission is presented. Building on Seasat experience, the NSCAT system includes several enhancements, such as three antenna azimuths in each of two swaths, and an onboard digital Doppler processor to allow backscatter measurements to be colocated everywhere within the orbit. These enhancements will greatly increase the quality of the NSCAT wind data. The ground processing of data is discussed, and scatterometers of the next decade are briefly described     

WAR,PEACE, AND FUZZY LOGIC

Our world is controlled by the Darwinian principle of survival of the fittest. In the causal equations of events, peace is a “trivial solution” that becomes lost, like a needle in a haystack, among war-bound “general solutions.” To find peace, we propose two routes. The first and perhaps preferred option is to leave the Darwinian universe of conflict and attempt to lay out our problems in a different setting in which the ruling principle is concord rather than conflict. The second path is to salvage peace from its triviality by compromising its purity and moving into a universe that redefines concord and conflict in a fuzzy way. We will show that the first approach (that we call transcendental) and the second track (that we call pragmatic) can overlap to define a realistic “Pathway to Peace.” The transcendental approach provides boundary conditions without which the generation of pragmatic rules becomes too complex and confusing.

We have used the universal laws of thermodynamics as a framework to understand the nature of conflict and to bridge between the hard and soft sciences. To this framework, we have added some fuzzy rules to pave the passage where transcendental and pragmatic realms of peace-making overlap. Though unity and equal relationships are underlying moral themes in conflict resolution, we show that peace cannot and should not be achieved by compromising diversity.     

Thermomechanical advantages of functionally graded dental posts: A finite element analysis

This study aimed to fabricate dental posts with functionally graded structures comprised of zirconia, titanium, and hydroxyapatite and compare their thermomechanical behavior with homogeneous zirconia and titanium posts in simulated models of upper central incisor. The results indicated the gradual behavior of functionally graded dental posts in terms of physical and mechanical properties. The finite element analysis revealed a more efficient equilibration to the oral environment after removing the thermal stress in functionally graded dental post compared to the homogeneous counterparts. Therefore, the functionally graded structures could reduce the stress/strain concentrations and interfacial stresses in root canal and minimize the likelihood of root fracture.     

Eccentricity Fault Diagnosis and Torque Ripple Analysis of a Four-pole Synchronous Reluctance Machine in Healthy and Faulty Conditions

Abstract—In this research, torque ripple is analyzed, considering both slot opening and distributed winding effects for a 4-pole 60-slot synchronous reluctance machine under healthy and eccentricity fault conditions. Mathematical-based models and numerical methods are used to study the behavior of the machine, especially when it is supplied with a voltage source. For this purpose, the parameters of the machine are computed in both healthy and eccentricity fault conditions using the winding function theory. This article proposes a method that deals with both dynamic and static eccentricity fault diagnosis using a vibration signature; consequently, the results demonstrate that the eccentricity fault has no significant effect on the machine's current signature. Moreover, unbalanced magnetic pull is computed considering eccentricity fault, and then mechanical instability is proven to occur under such circumstances. It should be noted that previous works were generally based on the finite-element method, and current sources were used as suppliers; in this article, a mathematical-based model is utilized and voltage sources are considered as suppliers, which are two main advantages of this article over previous ones. Verification carried out by simulation via the finite-element method supports the effectiveness of the model and control approach.     

A fast method to exactly calculate the diameter of incremental disconnected graphs

The breadth of problems requiring graph analytics is growing rapidly. Diameter is one of the most important metrics of a graph. The diameter is important in both designing algorithms for graphs and understanding the nature and evolution of graphs. Besides, the real world graphs are always changing. So detecting diameter in both static and dynamic graphs is very important. We first present an algorithm to calculate the diameter of the static graphs. The main goal of this algorithm is to reduce the number of breadth-first searches required to determine diameter of the graph. In addition, another algorithm is presented for calculating the diameter of incremental graphs. This algorithm uses the proposed static algorithm in its body. Based on experimental results, our proposed algorithm can detect diameter of both static and incremental graphs faster than existing approaches. To the best of our knowledge, the second algorithm is the first one that is able to efficiently determine the diameter of disconnected graphs that will be connected over time by adding new vertices.     

Efficient keyword search over graph-structured data based on minimal covered r-cliques

Frontiers of Information Technology & Electronic Engineering - Keyword search is an alternative for structured languages in querying graph-structured data. A result to a keyword query is a...     

Dispersion state and hyperelastic behavior of tire tread compounds reinforced with nanoclay: Uniaxial tensile and compression studies

Tire-tread compounds based on natural rubber, butadiene rubber, and styrene-butadiene rubber (65/20/15) were reinforced with Cloisite 15A. Clay state-of-dispersion in the ternary matrix (clay aspect ratio and clay/matrix interface yield strength) was estimated using Halpin–Tsai, Guth, and Leidner–Woodhams–Pukanszky micro-mechanical models. The aspect ratio suggested by Halpin–Tsai (9.7) and Guth (16) models both propounded partially intercalated microstructure. Transmission electron microscopy micrographs indicated higher reliability of Halpin–Tsai theory. Wetting parameter values indicated the affinity of Cloisite 15A to disperse in butadiene rubber. However, it seems that clay particles were not provided with proper compounding conditions to further stabilize their thermodynamic state. The poor matrix/clay adhesion was responsible for the decrease in matrix/clay interface strength and thickness upon increasing clay content according to Leidner–Woodhams–Pukanszky. Hyperelastic modeling was conducted using Abaqus software (five strain energy potential forms) on the basis of large deformation uniaxial tension/compression measurements. Effect of nanoclay on the crosslink-density of samples was justified by C₁₀ (Mooney–Rivlin) and locking-stretch (Van der Waals) values. The sample containing 1 phr nanoclay presented the best fit to the hyperelastic models among the rest conforming to its small value of global interaction parameter “a”(Van der Waals model) calculated explaining minimum deviations. Overall, Marlow and Ogden provided the best consistency with the experimental stress–strain results.     

Combination of surface texturing and nanostructure coating for reduction of light reflection in ZnO/Si heterojunction thin film solar cell

In this study, we report a single heterojunction solar cell based on n-type zinc oxide/p-type silicon. Three different solar cells were fabricated based on ZnO thin film on Si substrate, ZnO nanorods on Si substrate, and ZnO nanorods on micro-pyramidal structure of Si substrate. The comparison between these three kinds of solar cells was studied. Pyramidal structure of silicon was fabricated using chemical etching technique of p-type Si (100). The chemical solution consists of NaOH, isopropyl alcohol and hydrazine hydrate. The results showed that Si micro-pyramids can enhance optical absorption of Si substrates by increasing surface area and entrapping of incident light. For fabrication of uniform ZnO nanorods, a seed layer of ZnO was deposited on Si substrates via radio frequency magnetron sputtering technique. This layer can be used as an active n-type material in heterojunction solar cells as well. ZnO nanostructures can increase light absorption due to their high specific surface area. The combination of ZnO nanorods and Si micro-pyramids can enhance light trapping effect and increase the efficiency of solar cells. The structural and morphology of samples were studied using field-emission scanning electron microscopy, atomic force microscopy and X-ray diffractometry while the optical properties were investigated using photoluminescence and reflectance spectrometry. The efficiency and fill factor of solar cells were obtained from current–voltage characteristics using a solar simulator and a source-meter. The results showed that the efficiency of solar cell based on nanostructures of ZnO/micropyramids of Si is highly increased due to high anti-reflective behavior of this sample.     

A hybridization of simulated annealing and electromagnetic-like mechanism for job shop problems with machine availability and sequence-dependent setup times to minimize total weighted tardiness

In this paper, we explore job shop problems with two recently popular and realistic assumptions, sequence-dependent setup times and machine availability constraints to actualize the problem. The criterion is a minimization of total weighted tardiness. We establish a simple criterion to integrate machine availability constraints and scheduling decisions simultaneously. We propose a hybrid meta-heuristic to tackle the given problem. This meta-heuristic method, called EMSA, is a combination of two meta-heuristics: (1) Electromagnetic-like mechanism (EM); and (2) simulated annealing (SA). The hybridization is done to overcome some existing drawbacks of each of these two algorithms. To evaluate the proposed hybrid meta-heuristic method, we carry out a benchmark by which the proposed EMSA is compared with some existing algorithms as well as simulated annealing and electromagnetic-like mechanism alone in a fixed given computational time. All the related results and analysis obtained through the benchmark illustrate that our proposed EMSA is very effective and supersedes the foregoing algorithms.     

Self‐Assembly Behavior of Oppositely Charged Inverse Bipatchy Microcolloids

A directed attractive interaction between predefined “patchy” sites on the surfaces of anisotropic microcolloids can provide them with the ability to self‐assemble in a controlled manner to build target structures of increased complexity. An important step toward the controlled formation of a desired superstructure is to identify reversible electrostatic interactions between patches which allow them to align with one another. The formation of bipatchy particles with two oppositely charged patches fabricated using sandwich microcontact printing is reported. These particles spontaneously self‐aggregate in solution, where a diversity of short and long chains of bipatchy particles with different shapes, such as branched, bent, and linear, are formed. Calculations show that chain formation is driven by a combination of attractive electrostatic interactions between oppositely charged patches and the charge‐induced polarization of interacting particles.