Quantification of Axial Solids Mixing and Impacts of Internals in a Liquid-Solids Circulating Fluidized Bed Downer

Liquid solids circulating fluidized beds have great potential to be utilized in many chemical processes for their tremendous advantages. There are many studies about the riser but there is not any information on the downer as yet. This research is devoted to study the axial solids mixing in the downer. A new methodology was developed based on the concept of ion-exchanging ability of resins and the residence time distribution measurement. Resin particles were loaded with calcium ion as the tracer and Peclet number and the axial dispersion coefficient were determined for each set of operating conditions. Different designs of baffles were implemented in order to examine their effects on the axial solids dispersion. The results show that the baffles reduce the mixing substantially and their suppression effects increase with liquid velocity, except at very low liquid velocity where the presence of the baffle increases the mixing. Among the three designs – louver, mesh, and vertical plane, the louver has the most influence as it reduces the mixing coefficient by 60% when Ul = 3.86Umf. Under the same conditions, the mesh and vertical plane reduce the mixing coefficient by 46% and 32% respectively

Model Checking of Robot Gathering

Recent advances in distributed computing highlight models and algorithms for autonomous mo- bile robots that self-organize and cooperate together in order to solve a global objective. As results, a large number of algorithms have been proposed. These algorithms are given together with proofs to assess their correctness. However, those proofs are informal, which are error prone. This paper presents our study on formal verification of mobile robot algorithms. We first propose a formal model for mobile robot algorithms on anonymous ring shape network under multiplicity and asynchrony assumptions. We specify this formal model in Maude, a specification and pro- gramming language based on rewriting logic. We then use its model checker to formally verify an algorithm for robot gathering problem on ring enjoys some desired properties. As the result of the model checking, counterexamples have been found. We detect the sources of some unforeseen design errors. We, furthermore, give our interpretations of these errors

NITRIFICATION TREATMENT OF AMMONIUM POLLUTED HANOI GROUNDWATER USING A SWIM-BED TECHNOLOGY

Joint Research on Environmental Science and Technology for the Eart

A More Faithful Formal Definition of the Desired Property for Distributed Snapshot Algorithms to Model Check the Property

The first distributed snapshot algorithm was invented by Chandy and Lamport: Chandy-Lamport distributed snapshot algorithm (CLDSA). Distributed snapshot algorithms are crucial components to make distributed systems fault tolerant. Such algorithms are extremely important because many modern key software systems are in the form of distributed systems and should be fault tolerant. There are at least two desired properties such algorithms should satisfy: 1) the distributed snapshot reachability property (called the DSR property) and 2) the ability to run concurrently with, but not alter, an underlying distributed system (UDS). This paper identifies subtle errors in a paper on formalization of the DSR property and shows how to correct them. We give a more faithful formal definition of the DSR property; the definition involves two state machines - one state machine M_UDS that formalizes a UDS and the other M_CLDSA that formalizes the UDS on which CLDSA is superimposed (UDS-CLDSA) - and can be used to more precise model checking of the DSR property for CLDSA. We also prove a theorem on equivalence of our new definition and an existing one that only involves M_CLDSA to guarantee the validity of the existing model checking approach. Moreover, we prove the second property, namely that CLDSA does not alter the behaviors of UDS

Avoid Deadlock Resource Allocation (ADRA) Model V VM-out-of-N PM: Avoid Deadlock Resource Allocation (ADRA) Model V VM-out-of-N PM

This paper presents an avoid deadlock resource allocation (ADRA) for model V VM-out-of-N PM since cloud computing is a new computing paradigm composed of grid computing, distributed computing and utility concepts. Cloud computing presents a different resource allocation paradigm than either grids or distributed systems. Cloud service providers dynamically scale virtualized computing resources as a service over the internet. Due to variable number of users and limited resources, cloud is prone to deadlock at very large scale. Resource allocation and the associated deadlock avoidance is problem originated in the design and the implementation of the distributed computing, grid computing. In this paper, a new concept of free space cloud is proposed to avoid deadlock by collecting available free resource from all allocated users. New algorithms are developed for allocating multiple resources to competing services running in virtual machines on a heterogeneous distributed platform.  An experiment is tested in CloudSim. The performance of resource pool manager is evaluated by using CloudSim and resource utilization and indicating good results

DENITIRIFICATION TREATMENT OF NITRIFIED HANOI GROUNDWATER USING SWIM BED TECHNOLOGY

Joint Research on Environmental Science and Technology for the Eart

Welfare consequences of inconsistent monetary policy implementation in Vietnam

We develop a New Keynesian model featuring Calvo price setting and Calvo wage setting to quantify the welfare consequences of shifting trend inflation in Vietnam. To capture the characteristics of the Vietnamese economy, we use the Simulated Method of Moment and calibrate parameters jointly to match the important selected moments of Vietnamese data. The results show a severe consequence of a constant positive trend inflation and an exogenous shock to trend inflation, especially when a central bank sets a high level of inflation target. Among staggered price and wage contracts, the latter play a vital role in transmitting the adverse impacts of constant and shifting trend inflation into the economy. Based on our analyses, raising inflation targets would seem to be a bad policy prescription in Vietnam