Load distribution

The present paper approaches the loading distribution of trucks for Product Transportation as a rich problem. This is formulated with the classic Bin Packing Problem and five variants associated with a real case of study. A state of the art review reveals that related work deals with three variants at the most. Besides, they do not consider its relation with the vehicle routing problem. For the solution of this new rich problem a heuristic-deterministic algorithm was developed. It works together with a metaheuristic algorithm to assign routes and loads. The results of solving a set of real world instances show an average saving of three vehicles regarding their manual solution; this last needed 180 minutes in order to solve an instance and the actual methodology takes two minutes. On average, the demand was satisfied in 97.45%. As future work the use of a non deterministic algorithm is intended.

Many dynamic scheduling algorithms have been proposed in the past. With the advent of multi core processors, there is a need to schedule multiple tasks on multiple cores. The scheduling algorithm needs to utilize all the available cores efficiently. The multicore processors may be SMPs or AMPs with shared memory architecture. In this paper, we propose a dynamic scheduling algorithm in which the scheduler resides on all cores of a multi-core processor and accesses a shared Task Data Structure (TDS) to pick up ready-to-execute tasks. This method is unique in the sense that the processor has the onus of picking up tasks whenever it is idle. We have discussed the proposed scheduling algorithm using a set of tasks as an example. The paper concludes with the discussion of advantages and limitations of the proposed scheduling algorithm.

The accurate calculation of short-circuit currents is especially important for distribution protective relay setting and coordination. This paper presents a mutual comparison of distribution networks’ short-circuit calculation results, provided through three types of load approximations: 1) open circuits, 2) constant currents, and 3) constant impedances. This is done in order to determine how much different load modeling influence the calculation results. It is found that the level of influence is minor. Finally, an idea for the possible simplification of the protective relay current calculation is suggested.

This paper is concerned with timing belt drives transmitting fluctuating torques. A method is presented for calculating the loads on belt and pulley teeth given the belt strand forces as a function of time. Belt material properties, a generally existing pitch difference as well as friction forces between belt groove and pulley top land are taken into account. It is found that, due to the friction hysteresis, the load distribution at a particular time is affected by the preceding loading states. Experimentally determined loads on a pulley tooth in a drive transmitting a reversed and repeated torque are compared with calculated ones.In der vorliegenden Arbeit werden die Kräfteverhältnisse in Zahnriemenantrieben mit trapezförmigem Zahnprofil bei der Übertragung wechselnder Drehmomente untersucht. Unter der Voraussetzung, daβ die zeitlichen Verläufe von Leer- and Lasttrumkraft bekannt sind, wird ein Iterationsverfahren zur Berechnung der Zug- and Zahnkräfte entlang des Umschlingungsbogens vorgestellt. Die elastischen Eigenschaften der Zugstränge and Riemenzähne sowie ein i.allg. vorhandener fertigungsbedingter Unterschied zwischen Riemen- and Scheibenteilung werden dabei ebenso berück-sichtigt, wie die Reibkräfte zwischen Scheibenzahnkopf and Riemenhickengrund. Es wird gezeigt, daβ die Verteilung der in einem bestimmten Augenblick wirkenden Umfangskraft auf die einzelnen Zähne entlang des Umschlingungsbogens auch von der Vorgeschichte der Belastung abhängig ist. Um die Gültigkeit der Theorie zu prüfen, werden experimentell and theoretisch ermittelte Scheibenzahnkräfte bei der Übertragung eines reinen Wechseldrehmoments miteinander verglichen.

powering i.e. how to calculate the power required for a dump truck, what are the factors to be considered while deciding the power requirement and then select an engine which will provide sufficient power to dump truck. Load distribution i.e. how much load is coming on the front axle and rear axle when the truck is in moving on horizontal surface with zero % gradient. Also we will discuss the load distribution on front & rear axles when the dump truck is climbing a gradient and when the dump truck coming along the downhill. Weight transfer between the axles while climbing a gradient and while coming down through a downhill. This load distribution dictates the design of mainframe, wheel base distance, dump body design and selection of tires of a rigid dump truck. Braking i.e.in braking we will discuss about the stopping distance calculation as per ISO 3450 for rigid dump trucks and the actual measured stopping distance of a dump truck. Conditions for measuring the stopping distance of a dump truck, Effects of driver’s reaction, gradient, speed and brake response on the stopping distance and the brake ratio generally used in the dump trucks. Braking is very important in safety point of view.

The unsteady thin airfoil theory of von Karman and Sears is extended to analyze the aerodynamic characteristics of a deforming airfoil. The von Karman and Sears approach is employed along with Neumark’s method for the unsteady load distribution. The wake-effect terms are calculated using either the Wagner or Theodorsen function, depending on the desired camberline deformation. The concept of separating the steady and damping terms in the camberline boundary condition is introduced. The influence of transient and sinusoidal airfoil deformations on the airfoil load distribution is examined. The general equations developed for the unsteady lift and load distribution are evaluated analytically for a morphing airfoil, which is defined here by two quadratic curves with arbitrary coefficients. This general camberline is capable of modeling a wide range of practical camberline shapes, including leading and trailing edge flaps. Results of the present model are shown for a variable camber, or morphing, airfoil configuration. The influence of transient and sinusoidal motion on the force coefficients and load distribution is addressed.

Cloud computing providers have setup several data centers at different geographical locations over the Internet in order to optimally serve needs of their customers around the world. However, existing systems do not support mechanisms and policies for dynamically coordinating load distribution among different Cloud-based data centers in order to determine optimal location for hosting application services to achieve reasonable QoS levels. Further, the Cloud computing providers are unable to predict geographic distribution of users consuming their services, hence the load coordination must happen automatically, and distribution of services must change in response to changes in the load. To counter this problem, we advocate creation of federated Cloud computing environment (InterCloud) that facilitates just-in-time, opportunistic, and scalable provisioning of application services, consistently achieving QoS targets under variable workload, resource and network conditions. The overall goal is to create a computing environment that supports dynamic expansion or contraction of capabilities (VMs, services, storage, and database) for handling sudden variations in service demands. This paper presents vision, challenges, and architectural elements of InterCloud for utility-oriented federation of Cloud computing environments. The proposed InterCloud environment supports scaling of applications across multiple vendor clouds. We have validated our approach by conducting a set of rigorous performance evaluation study using the CloudSim toolkit. The results demonstrate that federated Cloud computing model has immense potential as it offers significant performance gains as regards to response time and cost saving under dynamic workload scenarios.

Effects of bolt-hole clearance on the stiffness and strength of composite bolted joints were investigated. The configuration studied was single-lap, single-bolt. Four different clearances were obtained using variable size reamers, ranging from neat-fit to 240 μm. The specimens were manufactured in accordance with ASTM standard D5961/D5961 M-96, from graphite/epoxy HTA/6376, with quasi-isotropic and zero-dominated lay-ups. Both protruding head and countersunk bolts were used, with two different applied torque levels. Specimen dimensions were chosen to obtain bearing as the primary mode of failure, with ultimate failure being mostly through bolt failure. Joint stiffness, 2% offset bearing strength, ultimate bearing strength and ultimate bearing strain were obtained according to the Standard. In addition, an alternative definition of strength was derived, which has some advantages over the offset method, and the results were evaluated according to this definition. Increasing clearance was found to result in reduced joint stiffness and increased ultimate strain in all tested configurations. Finger-tight joints with protruding head bolts showed a link between clearance and strength, but countersunk and torqued joints did not. A delay in load take-up also occurred with the higher clearance joints, which has implications for load distributions in multi-bolt joints.