Integrated Flow Shop and Vehicle Routing Problem Based on Tabu Search Algorithm

We consider in this paper a m-machine permutation flow shop scheduling problem and vehicle routing problem (VRP) integrated [1]. The manufacturing workshop is a flow shop and there is only one vehicle available. We are interested in the minimization of the total tardiness. related to the delivery completion times. Therefore, we are faced to three interdependent problems: scheduling the jobs in the flow shop environment, batching the completed jobs, and routing the batches. Then, we present the resolution method based on Tabu search and the results that have been obtained. Computational experiments are performed on random data sets and show the efficiency of the methods. Finally, a conclusion and some future research directions are proposed

BOUNDS FOR VOLUMES OF SUB-LEVEL SETS OF POLYNOMIALS AND APPLICATIONS

In this paper, we present some explicit exponents in the estimates for the volumes of sub-level sets of polynomials on bounded sets and applications to the decay of oscillatory integrals and the convergence of singular integrals

Long-term stability studies of a semiconductor photoelectrode in three-electrode configuration

Improving the stability of semiconductor materials is one of the major challenges for sustainable and economic photoelectrochemical water splitting. N-terminated GaN nanostructures have emerged as a practical protective layer for conventional high efficiency but unstable Si and III-V photoelectrodes due to their near-perfect conduction band-alignment, which enables efficient extraction of photo-generated electrons, and N-terminated surfaces, which protects against chemical and photo-corrosion. Here, we demonstrate that Pt-decorated GaN nanostructures on an n+-p Si photocathode can exhibit an ultrahigh stability of 3000 h (i.e., over 500 days for usable sunlight ∼5.5 h per day) at a large photocurrent density (>35 mA cm-2) in three-electrode configuration under AM 1.5G one-sun illumination. The measured applied bias photon-to-current efficiency of 11.9%, with an excellent onset potential of ∼0.56 V vs. RHE, is one of the highest values reported for a Si photocathode under AM 1.5G one-sun illumination. This study provides a paradigm shift for the design and development of semiconductor photoelectrodes for PEC water splitting: stability is no longer limited by the light absorber, but rather by co-catalyst particles

Social Housing for Workers in Industrial Zones in Vietnam - Concepts and Practical Solutions towards Sustainable Development. The Case Studies of Hanoi City

Economic growth associated with the rapid industrialization and urbanization over the past 30 years since Doi Moi (Reform) has facilitated the establishment and development of many industrial zones (IZs) in major cities of Vietnam. The high concentration of IZs in the largest cities has attracted millions of industrial laborers and created large migration waves from rural to urban areas. Establishing and improving the living environment of workers have become a huge pressure for the Government and local authorities across the country to deal with. Although the Government has issued numerous policies and incentives to encourage and support housing development for factory workers, there are still many conflicts and challenges in policy implementation. Through observational and questionnaire surveys supported with in-depth interviews of experts in urban planning and management, the research aims to understand clearly the context of social housing development for IZ workers in Vietnam recently, to demonstrate outstanding characters of different types of housing for factory workers as well as crucial issues related to social housing and informal housing for factory workers. Furthermore, the research proposes solutions including legal institutions, management mechanisms, industrial worker housing database establishment, and basic technical solutions (planning and spatial organization) in order to find out some appropriate concepts for social housing targeted at industrial workers and then to achieve social sustainable development

Impact of Agency Costs on Firm Performance: Evidence from Vietnam

An assumption in agency costs theory is that agency costs can exert a negative impact on firm performance. In this study, we examine the impact of agency costs on firm performance of Vietnamese listed companies. Our sample includes 736 companies in Vietnam during the period om 2010 to 2015. We find that agency costs exert a negative impact on firm performance. Our results are robust to alternative econometric models, including an instrumental variables technique and a system generalized method of moment model. In addition, we show that a debt instrument can be a useful tool to reduce the negative impact of agency costs on firm performance

Fish distribution in the Ba Che and Tien Yen rivers

The ichthyo-fauna in the Ba Che and Tien Yen rivers, northern Vietnam is highly diverse, with a total of 245 species determined. However, data on the distribution of fish species are not sufficiently provided for the whole area. This study was conducted from 2008 to 2011 at 27 stations from the Ba Che and Tien Yen river basins to determine the distribution of fish species according to different sections of the rivers, water bodies, seasons, and salinity levels. The results show that fish species are distributed mainly in the river (with 210 species), concentrated in the downstream area (with 213 species). Fishes are mainly collected in the dry season when the salinity level of river is high, due to seawater intrusion which also brings in 160 species of marine fish. This shows that fish distribution in the research areas is mainly dominated by the presence of marine species. While for freshwater fish, it is clearly affected by the mountainous features. Apart from the common characteristics sharing between the two river basins, but the number of both freshwater and marine fish species in the Tien Yen river are larger than those of Ba Che river, which is related to fresh water surface, river morphology, the width and location of the estuary to the sea. The downstream area is home to the fish species recorded in the Red Data Book of Vietnam and the complementary species for Vietnam, while the middle and upstream of the rivers may offer a high potential of biodiversity, with many possibly new species for science. These are important data for the conservation and sustainable development of fish resources in the Ba Che and Tien Yen river basins.