An order batching and processing heuristic to address aisle congestion in a manual order picking warehouse with order due dates

A heuristic for batching orders in a manual order-picking warehouse has been developed. It prioritizes orders based on due time to prevent mixing of orders of different priority levels. The order density of aisles criterion is used to form batches. It also determines the number of pickers required and assigns batches to pickers such that there is a uniform workload per unit of time. The effectiveness of the heuristic was studied by observing computational time and aisle congestion for various numbers of total orders and number of orders that form a batch. An initial heuristic performed well for small number of orders, but for larger number of orders, a partitioning technique is computationally more efficient, needing only minutes to solve for thousands of orders, while preserving 90% of the batch quality obtained with the original heuristic. Comparative studies between the heuristic and other published heuristics are needed. ^

Study of carbon nanotube film and shape memory alloys treatment for sensing and structural vibration control

Structural vibration control is of great importance. Current active and passive vibration control strategies usually employ individual elements to fulfill this task, such as viscoelastic patches for providing damping, transducers for picking up signals and actuators for inputting actuating forces. The goal of this dissertation work is to design, manufacture, investigate and apply a new type of multifunctional composite material for structural vibration control. This new composite, which is based on multi-walled carbon nanotube (MWCNT) film, is potentially to function as free layer damping treatment and strain sensor simultaneously. That is, the new material integrates the transducer and the damping patch into one element. The multifunctional composite was prepared by sandwiching the MWCNT film between two adhesive layers. Static sensing test indicated that the MWCNT film sensor resistance changes almost linearly with the applied load. Sensor sensitivity factors were comparable to those of the foil strain gauges. Dynamic test indicated that the MWCNT film sensor can outperform the foil strain gage in high frequency ranges. Temperature test indicated the MWCNT sensor had good temperature stability over the range of 237 K-363 K. The Young’s modulus and shear modulus of the MWCNT film composite were acquired by nanoindentation test and direct shear test, respectively. A free vibration damping test indicated that the MWCNT composite sensor can also provide good damping without adding excessive weight to the base structure. A new model for sandwich structural vibration control was then proposed. In this new configuration, a cantilever beam covered with MWCNT composite on top and one layer of shape memory alloy (SMA) on the bottom was used to illustrate this concept. The MWCNT composite simultaneously serves as free layer damping and strain sensor, and the SMA acts as actuator. Simple on-off controller was designed for controlling the temperature of the SMA so as to control the SMA recovery stress as input and the system stiffness. Both free and forced vibrations were analyzed. Simulation work showed that this new configuration for sandwich structural vibration control was successful especially for low frequency system.

ALBA: A Political Tool for Venezuela’s Foreign Policy

Despite its founding by Hugo Chávez on the heels of the failed Free Trade Area for the Americas (FTAA) negotiations which took place November 2003, the Bolivarian Alliance for the Americas (ALBA, as it is known for its Spanish acronym) has evolved into a political tool that uses “social power” to facilitate Venezuela‟s positioning as the leader of the anti-U.S. agenda in the region. Fostering political favors and goodwill through the financing of social development projects, ALBA has created a political environment whereby countries on the take and their respective leaders seem deterred from taking public opposing viewpoints to Chávez. To that end, it has provided billions in economic aid to several nations in Latin American and the Caribbean, winning their favor and support for its policies. To date, ALBA counts on eight member nations. Besides Venezuela, it includes Antigua and Barbuda, Bolivia, Cuba, Dominica, Ecuador, Nicaragua, and Saint Vincent and the Grenadines. It also has several observer nations, among them, Grenada, Haiti, Paraguay, Uruguay, and a non-Latin American country, Syria. Throughout its recent history Venezuela has used its oil wealth to pursue political capital. Under the Chávez government it is doing so as part of a strategic effort countering the U.S. Following Cuba‟s demise in the region as the anti-American socialist camp leader, Chávez is attempting to step into Cuba‟s shoes, picking up where Cuba left off over a decade ago and has used the ALBA as a mechanism to help promote his foreign policy. Relying on its own resources, not those of the Soviet Union as Cuba once did, Venezuela has already shown its influence in the international arena, challenging U.S. positions at the Organization of American States (OAS), the United Nations, and even in matters having little if nothing to do with the region, such as Iran‟s nuclear proliferation. Taking advantage of Venezuela‟s oil prices bonanza, Chávez has been spreading economic aid throughout the region, funding several development projects. From stepping in to buy Bolivia‟s soy beans when the U.S. ceased doing so, to helping finance and construct an airport in Dominica, Venezuela‟s ALBA has provided assistance to many states in the region. As in the past, Venezuela has invested significantly both in time and money in the Caribbean, providing development assistance and oil at a discount to Haiti, St. Kitts and Nevis, and the Dominican Republic, although the latter two are neither member nor observer states of ALBA. The aid Chávez has been spreading around may be coming at a cost. It seems it has begun to cause cracks within the CARICOM community, where ALBA already counts on six of its 15 members, leading experts and leaders in the region to question traditional alliances to each other and the U.S. Yet, ALBA‟s ability to influence through aid is dependent on the Venezuelan economy. Its success hinges on continued Venezuelan oil sales at stable prices and the ability of Chávez to remain in power.