Dynamical Casimir Effect for a Swinging Cavity

The resonant scalar particle generation for a swinging cavity resonator in the Casimir vacuum is examined. It is shown that the number of particles grows exponentially when the cavity rotates at some specific external frequency.Comment: to appear in J. Phys. A: Math. Theo

An enhancement to the Bees Algorithm with slope angle computation and Hill Climbing Algorithm and its applications on scheduling and continuous-type optimisation problem

This paper focuses on improvements to the Bees Algorithm (BA) with slope angle computation and Hill Climbing Algorithm (SACHCA) during the local search process. First, the SAC was employed to determine the inclination of the current sites. Second, according to the slope angle, the HCA was utilised to guide the algorithm to converge to the local optima. This enabled the global optimum of the given problem to be found faster and more precisely by focusing on finding the available local optima first before turning the attention on the global optimum. The proposed enhancements to the BA have been tested on continuous-type benchmark functions and compared with other optimisation techniques. The results show that the proposed algorithm performed better than other algorithms on most of the benchmark functions. The enhanced BA performs better than the basic BA, in particular on higher dimensional and complex optimisation problems. Finally, the proposed algorithm has been used to solve the single machine scheduling problem and the results show that the proposed SAC and HCA-BA outperformed the basic BA in almost all the considered instances, in particular when the complexity of the problem increases

Vortices and chirality of magnetostatic modes in quasi-2D ferrite disk particles

In this paper we show that the vortex states can be created not only in magnetically soft "small" (with the dipolar and exchange energy competition) cylindrical dots, but also in magnetically saturated "big" (when the exchange is neglected) cylindrical dots. A property associated with a vortex structure becomes evident from an analysis of confinement phenomena of magnetic oscillations in a ferrite disk with a dominating role of magnetic-dipolar (non-exchange-interaction) spectra. In this case the scalar (magnetostatic-potential) wave functions may have a phase singularity in a center of a dot. A non-zero azimuth component of the flow velocity demonstrates the vortex structure. The vortices are guaranteed by the chiral edge states of magnetic-dipolar modes in a quasi-2D ferrite disk

Seasonal variation of the cold intermediate water in the Southwestern Black Sea and its interaction with the Sea of Marmara during the period of 1996-1998

Seasonal variations of the cold intermediate water (CIW) in the southwestern Black Sea and its entrance into the Strait of Istanbul (Bosphorus) within the upper layer flow have been studied by using monthly oceanographic data sets collected in 1996-1998 period. In addition, the advection of the CIW via Strait Of Istanbul to the Sea of Marmara has been investigated.The CIW is a permanent and characteristic water mass of the Black Sea, markedly observed in the northwestern Black Sea. It is transported with the Rim Current along the boundary of the basin. The average temperature of the CIW is about 6o C. The 8oC isotherms defines its upper and lower boundaries. The upper boundary of CIW rises up to the 20 m depth in the shelf and coastal upwelling regions with a thickness of 40 m. On the other hand, the depth of the upper boundary may decrease down to 40 m with a thickness of 120 m in the anticyclonic regions.The CIW, located between 30 and 65m depths, was observed from April to September at the northern approaches of the Strait of Istanbul in the Black Sea. However, the CIW, within the Black Sea's upper layer flow, does not enter into the strait in the beginning (April, May) and at the end (September) of this period. The CIW between 20 and 50m water depths was observed in the northern entrance of the strait in summer (June, July and August) and it was carried into the strait by the southbound surface current. Its temperature increases southwards along the strait, due to the mixing with the warmer surface and bottom layers. This increment ranges between 2 and 4oC depending on the rate of mixing. The physically altered waters enter the Sea of Marmara with temperature of 11-14oC.In the Sea of Marmara, a residual cold intermediate layer (CIL) is observed in summer, it is just placed on top of the halocline. The average temperature of the upper layer increases from spring to autumn. In some months, however, there is a decrement in the average temperature of the upper layer. The altered CIW waters entering the Sea of Marmara may be responsible for this cooling

Seasonal variation of the cold intermediate water in the Southwestern Black Sea and its interaction with the Sea of Marmara during the period of 1996-1998

Seasonal variations of the cold intermediate water (CIW) in the southwestern Black Sea and its entrance into the Strait of Istanbul (Bosphorus) within the upper layer flow have been studied by using monthly oceanographic data sets collected in 1996-1998 period. In addition, the advection of the CIW via Strait Of Istanbul to the Sea of Marmara has been investigated.The CIW is a permanent and characteristic water mass of the Black Sea, markedly observed in the northwestern Black Sea. It is transported with the Rim Current along the boundary of the basin. The average temperature of the CIW is about 6o C. The 8oC isotherms defines its upper and lower boundaries. The upper boundary of CIW rises up to the 20 m depth in the shelf and coastal upwelling regions with a thickness of 40 m. On the other hand, the depth of the upper boundary may decrease down to 40 m with a thickness of 120 m in the anticyclonic regions.The CIW, located between 30 and 65m depths, was observed from April to September at the northern approaches of the Strait of Istanbul in the Black Sea. However, the CIW, within the Black Sea's upper layer flow, does not enter into the strait in the beginning (April, May) and at the end (September) of this period. The CIW between 20 and 50m water depths was observed in the northern entrance of the strait in summer (June, July and August) and it was carried into the strait by the southbound surface current. Its temperature increases southwards along the strait, due to the mixing with the warmer surface and bottom layers. This increment ranges between 2 and 4oC depending on the rate of mixing. The physically altered waters enter the Sea of Marmara with temperature of 11-14oC.In the Sea of Marmara, a residual cold intermediate layer (CIL) is observed in summer, it is just placed on top of the halocline. The average temperature of the upper layer increases from spring to autumn. In some months, however, there is a decrement in the average temperature of the upper layer. The altered CIW waters entering the Sea of Marmara may be responsible for this cooling

Hybrid Genetic Bees Algorithm applied to Single Machine Scheduling with Earliness and Tardiness Penalties

This paper presents a hybrid Genetic-Bees Algorithm based optimised solution for the single machine scheduling problem. The enhancement of the Bees Algorithm (BA) is conducted using the Genetic Algorithm's (GA's) operators during the global search stage. The proposed enhancement aims to increase the global search capability of the BA gradually with new additions. Although the BA has very successful implementations on various type of optimisation problems, it has found that the algorithm suffers from weak global search ability which increases the computational complexities on NP-hard type optimisation problems e.g. combinatorial/permutational type optimisation problems. This weakness occurs due to using a simple global random search operation during the search process. To reinforce the global search process in the BA, the proposed enhancement is utilised to increase exploration capability by expanding the number of fittest solutions through the genetical variations of promising solutions. The hybridisation process is realised by including two strategies into the basic BA, named as â\u80\u9creinforced global searchâ\u80\u9d and â\u80\u9cjumping functionâ\u80\u9d strategies. The reinforced global search strategy is the first stage of the hybridisation process and contains the mutation operator of the GA. The second strategy, jumping function strategy, consists of four GA operators as single point crossover, multipoint crossover, mutation and randomisation. To demonstrate the strength of the proposed solution, several experiments were carried out on 280 well-known single machine benchmark instances, and the results are presented by comparing to other well-known heuristic algorithms. According to the experiments, the proposed enhancements provides better capability to basic BA to jump from local minima, and GBA performed better compared to BA in terms of convergence and the quality of results. The convergence time reduced about 60% with about 30% better results for highly constrained jobs

A Multi-Objective Optimization for Supply Chain Network Using the Bees Algorithm

A supply chain is a complex network which involves the products, services and information flows between suppliers and customers. A typical supply chain is composed of different levels, hence, there is a need to optimize the supply chain by finding the optimum configuration of the network in order to get a good compromise between the multi-objectives such as cost minimization and lead-time minimization. There are several multi-objective optimization methods which have been applied to find the optimum solutions set based on the Pareto front line. In this study, a swarm-based optimization method, namely, the bees algorithm is proposed in dealing with the multi-objective supply chain model to find the optimum configuration of a given supply chain problem which minimizes the total cost and the total lead-time. The supply chain problem utilized in this study is taken from literature and several experiments have been conducted in order to show the performance of the proposed model; in addition, the results have been compared to those achieved by the ant colony optimization method. The results show that the proposed bees algorithm is able to achieve better Pareto solutions for the supply chain problem

Sea level changes along the Turkish coasts of the Black Sea, the Aegean Sea and the Eastern Mediterranean

Short, tidal, subtidal, seasonal, secular sea-level variations, sea-level differences and interactions between the basins have been studied, based on the data collected at some permanent and temporary tide gauges located along the Turkish coasts, mostly along the Straits connecting the Marmara Sea to outer seas. Even though the deficiency of sufficient information prevented us to reach the desired results, many pre-existed studies have been improved. Short-period oscillations were clearly identified along the Turkish Strait System and related to their natu-ral periods. The tidal amplitudes are low along the Turkish coasts, except northern Aegean and eastern Mediterranean. The stability of harmonic constants of Samsun and Antalya were examined and most of the long period constituents were found to be unstable. Even the Marmara Sea is not affected from the tidal oscillations of Black and Aegean Seas, some interactions in low frequency band have been detected. Subtidal sea level fluctuations (3-14 day) have relations with the large-scale cyclic atmospheric patterns passing over the Turkish Straits System. Short-term effects of wind on sea level are evident.Seasonal sea-level fluctuations along the Turkish Straits System are in accord with Black Sea's hydrological cycle. The differential range of the monthly mean sea levels between the Black Sea and the Marmara Sea is highly variable; high during spring and early summer and low during fall and winter.On the average, there is a pronounced sea-level difference (55 cm) along the Turkish Straits System. However, the slope is nonlinear, being much steeper in the Strait of Istanbul. This barotrophic pressure difference is one of the most important factors causing the two-layer flow through the system. The topography and hydrodynamics of the straits, the dominant wind systems and their seasonal variations make this flow more complicated. For secular sea level changes, a rise of 3.2 mm/a was computed for Karsiyaka (1935-71) and a steady trend (-0.4 mm /a) has been observed for annual sea levels at Antalya (1935-77). The decreasing trend (-6.9 mm/a) at Samsun is contrary to the secular rising trend of the Black Sea probably because of its rather short monitoring period (1963-77)