Lamia Belfares

Bio: Lamia Belfares is an academic researcher from Laval University. The author has contributed to research in topics: Scheduling (computing) & Tabu search. The author has an hindex of 6, co-authored 8 publications receiving 197 citations.

Heat and Mass Transfer in Cocurrent Gas−Liquid Packed Beds. Analysis, Recommendations, and New Correlations

Abstract: Meticulous inspection of the literature has unveiled the weakness of several empirical methods for predicting the macroscopic mass- and heat-transfer characteristics relevant to gas−liquid cocurrent downflow and upflow packed-bed reactors. In response, using a wide experimental database consisting of 5279 measurements for trickle beds (downflow) and 1974 measurements for packed bubble columns (upflow), a set of reliable correlations has been recommended for the prediction of the gas−liquid interfacial area (agl), the volumetric liquid- (kla) and gas-side (kga) mass-transfer coefficients, the wall (ηeklw) and bed (ηekls) liquid−solid mass-transfer coefficients, the wall heat-transfer coefficient (hw), the bed effective radial thermal conductivity (λe), and the particle-to-fluid heat-transfer coefficient (hp). Some of these correlations are from the literature, and others have been developed by combining artificial neural networks and dimensional analysis. The accuracy of the proposed correlations surpasses...

Three-Phase Fluidization Macroscopic Hydrodynamics Revisited

Abstract: The state-of-the-art tools for the evaluation of the macroscopic hydrodynamics of cocurrent upflow three-phase fluidization are critically evaluated by thoroughly interrogating the broadest fluidization database ever built. The database is compiled through worldwide conjoint initiatives as a result of a decade of compilation efforts by the groups of professors L. S. Fan (Columbus, OH), S. D. Kim (Seoul, South Korea), and G. Wild (Nancy, France) and our Laval University group. The database represents almost the whole heritage of the nonproprietary data released in the open literature in the field of gas−liquid−solid fluidization (23 000 experiments on bed porosity and liquid, gas, and solid holdups). It is dedicated to embracing wide-ranging fluids' properties, particle and vessel sizes, and operating conditions. The database contains 55 Newtonian (20 500 data), 19 non-Newtonian liquids (2500 data), 110 various particles, and 17 different column diameters and includes wall effect ratios Dc/dp and grain siz...

Multiobjective evolutionary algorithms: A survey of the state of the art

Abstract: A multiobjective optimization problem involves several conflicting objectives and has a set of Pareto optimal solutions. By evolving a population of solutions, multiobjective evolutionary algorithms (MOEAs) are able to approximate the Pareto optimal set in a single run. MOEAs have attracted a lot of research effort during the last 20 years, and they are still one of the hottest research areas in the field of evolutionary computation. This paper surveys the development of MOEAs primarily during the last eight years. It covers algorithmic frameworks such as decomposition-based MOEAs (MOEA/Ds), memetic MOEAs, coevolutionary MOEAs, selection and offspring reproduction operators, MOEAs with specific search methods, MOEAs for multimodal problems, constraint handling and MOEAs, computationally expensive multiobjective optimization problems (MOPs), dynamic MOPs, noisy MOPs, combinatorial and discrete MOPs, benchmark problems, performance indicators, and applications. In addition, some future research issues are also presented.

Multiphase catalytic reactors: a perspective on current knowledge and future trends

Abstract: Conventional and emerging processes that require the application of multiphase reactors are reviewed with an emphasis on catalytic processes. In the past, catalyst discovery and development preceded and drove the selection and development of an appropriate multiphase reactor type. This sequential approach is increasingly being replaced by a parallel approach to catalyst and reactor selection. Either approach requires quantitative models for the flow patterns, phase contacting, and transport in various multiphase reactor types. This review focuses on these physical parameters for various multiphase reactors. First, fixed-bed reactors are reviewed for gas-phase catalyzed processes with an emphasis on unsteady state operation. Fixed-bed reactors with two-phase flow are treated next. The similarities and differences are outlined between trickle beds with cocurrent gas–liquid downflow, trickle-beds with countercurrent gas–liquid flow, and packed-bubble columns where gas and liquid are contacted in coc...

IoT Resource Allocation and Optimization Based on Heuristic Algorithm

Abstract: The Internet of Things (IoT) is a distributed system that connects everything via internet. IoT infrastructure contains multiple resources and gateways. In such a system, the problem of optimizing IoT resource allocation and scheduling (IRAS) is vital, because resource allocation (RA) and scheduling deals with the mapping between recourses and gateways and is also responsible for optimally allocating resources to available gateways. In the IoT environment, a gateway may face hundreds of resources to connect. Therefore, manual resource allocation and scheduling is not possible. In this paper, the whale optimization algorithm (WOA) is used to solve the RA problem in IoT with the aim of optimal RA and reducing the total communication cost between resources and gateways. The proposed algorithm has been compared to the other existing algorithms. Results indicate the proper performance of the proposed algorithm. Based on various benchmarks, the proposed method, in terms of "total communication cost", is better than other ones.

Human resource rightsizing using centralized data envelopment analysis: Evidence from Taiwan's Airports

Abstract: Centralized human resource reallocation involves deciding how to fit change in a way that maximizes aggregated outputs. This paper presents an alternative approach to reallocating human resources. Specifically, an aggregated concept in the form of data envelopment analysis (DEA) is used to construct a modified centralized DEA model that is combined with a Russell measure and applied to three different human resource reallocation policies. An application to illustrate manpower rightsizing in an airport organizational setting in Taiwan is also demonstrated using centralized DEA for regular and/or contracted employees. The results demonstrate that the application is effective in reducing and/or transferring staff, while maximizing organizational output levels and implementing smooth downsizing. The results also present directions for possible improvements in workplace efficiency.