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Effect of Two Liquid Phases on the Separation Efficiency of Distillation Columns

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Advances in Chemical Engineering and Science 2013年第1期3卷 1-8页

作者： Gardênia Marinho Cordeiro Stephanie Rolim Dantas Luís Gonzaga Sales Vasconcelos romildo pereira brito Department of Chemical Engineering Federal University of Campina Grande Campina Grande Brazil

Distillation is one of the oldest and most important separation processes used in the chemical and petrochemical industries. On the other hand, it is a process the thermodynamic efficiency of which is very low, and therefore reducing the consumption of energy is one of the targets of research studies on distillation. This article arose from seeking to reduce energy consumption in a distillation train of 1,2-dichloroethane (ethylene dichloride-EDC) of a commercial plant producing vinyl monochloride (VMC), which involves an azeotropic distillation column. The reduction in the reboiler heat duty caused significant changes in concentration and temperature profiles throughout the column due to the formation of two liquid phases. The results show that, although very small in percentage terms (less than 2.5%), the appearance of the 2nd liquid phase causes significant changes in the operation of the column and the separation achieved.

关键词： Distillation Azeotropic Two Liquid Phases Separation Factor

Effect of a commercial dispersion of multi walled carbon nanotubes on the hydration of an oil well cementing paste

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Frontiers of Structural and Civil Engineering 2016年第2期10卷 174-179页

作者： Ocar Aurelio MENDOZA REALES William C. PEARL Jr Maria D. M. PAIVA Cristiane R. MIRANDA romildo Dias TOLEDO FILHO Civil Engineering Department PEC/COPPE Universidade Federal do Rio de Janeiro Rio de Janeiro 21941-972 Brazil Halliburton Brazil Technology Center Halliburton Rio de Janeiro 21941-907 Brazil CPetrobras Petroleo Brasileiro S.A Rio de Janeiro 21941-901 Brazil

This work studies the influence of a commercial dispersion of multi wall carbon nanotubes （MWCNT） on the hydration of a class G cement paste, at room and elevated down-hole temperatures. The MWCNT dispersion was produced with a solids concentration of 3.0 % by mass and an anionic surfactant as dispersing agent. Cement pastes with water-to-cement ratio of 0.45 and additions of solid MWCNT by mass of cement up to 0.50 % were studied. Isothermal calorimetry results showed a clear retardation of the hydration of cement caused by the surfactant contained in the MWCNT dispersion. Nevertheless, thermogravimetric evaluations showed that once the hydration reaction resumed, the retardation effect of the surfactant did not have a negative impact on the amount of hydration products precipitated. It was concluded that the commercial MWCNT dispersion presents a good potential to be applied in oil well cement pastes.

关键词： carbon nanotubes surfactant retardation combined water C-S-H

Guy Structure with Galvanic Corrosion： Case Study

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Journal of Civil Engineering and Architecture 2016年第7期10卷 792-797页

作者： romildo Alves Berenguer Edmilson Raimundo de Oliveira Junior Marcus Wagner pereira da Silva Glauber Beirao de Souza Paulo Helene Eliana Cristina Barreto Monteiro Department of Civil Engineering University of Pernambuco Recife 51110-200 Brazil Department of Civil Engineering Catholic University of Pernambuco Reeife 51110-200 Brazil Ph.D.-Engenharia Department of Civil Engineering Street Viscount in Black Gold S6o Paulo 01303-060 Brazil

Reinforcement bar corrosion depends heavily on environment and the processes used. This study will address galvanic corrosion. Based on a case study of galvanic corrosion in a guyed power transmission tower, experiments using a number of methods were made on a small sample of eight poles chosen for excavation and visual inspection, to assess the various resulting diagnoses. Method that provided the best results both in location and classification of the points was adopted, where corrosion had already begun, considering the concern of finding a non-evasive process. To diagnose the status of the poles inserted in rock, after applying the methods, the main types of corrosion affecting them were listed and classified. With the results, the possible means of preventing and maintaining the structure were presented.

关键词： Corrosion diagnosis inspection.

A Strategy of Density-Based Partitioning for Scalability Problem in Network Self-management

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Computer Technology and Application 2013年第8期4卷 437-443页

作者： romildo Martins da Silva Bezerra Joberto Sergio Barbosa Martins GSORT / Federal Institute of Bahia Salvador Bahia 40301-015 Brazil NUPERC / Salvador University Salvador Bahia 41820-160 Brazil

A density-based partitioning strategy is proposed for large domain networks in order to deal with the scalability issue found in autonomic networks considering, as a scenario, the autonomic Quality of Service （QoS） management context. The approach adopted focus as on obtaining dense network partitions having more paths for a given vertices set in the domain. It is demonstrated that dense partitions improve autonomic processing scalability, for instance, reducing routing process complexity. The solution looks for a significant trade-off between partition autonomic algorithm execution time and path selection quality in large domains. Simulation scenarios for path selection execution time are presented and discussed. Authors argue that autonomic networks may benefit from the dense partition approach proposed by achieving scalable, efficient and near real-time support for autonomic management systems.

关键词： Network management self-management scalability.

Stability Analysis of Tubular Steel Shores

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Journal of Civil Engineering and Architecture 2016年第5期10卷 563-567页

作者： Febio Andre Frutuoso Lopes Femando Artur Nogueira Silva Romilde Almeida de Oliveira romildo Alves Berenguer Department of Civil Engineering Catholic University of Pernambuco Recife 51110-200 Brazil

The design of tubular steel scaffold-type shoring is usually performed by calculating the load capacity of the elements, taking into account their axial strength, mainly. Geometric stiffness effects and changes in the stiffness of connections are seldom considered. This paper assesses the stability of tubular steel shores using experimental and numerical approaches that take into account geometric nonlinearities as well as the features of the elements used to make the link between the steel tubes （pressed double coupler--right angle）. The increase in overall stiffness generated by diagonal bars used in the analyzed models was examined. The results obtained show the importance of using P-delta analyses in this kind of structure in order to evaluate structure＇s overall stability even when compressive stresses are within acceptable ranges of code limits.

关键词： Tubular steel shores global stability semi-rigid connections P-delta analyses.

Numerical Staged Construction Analysis of Precast Concrete Bridge

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Journal of Civil Engineering and Architecture 2016年第4期10卷 447-451页

作者： Ana Cecilia Ferreira Leite Fernando Artur Nogueira Silva romildo Alves Berenguer Romilde Almeida de Oliveira Department of Civil Engineering Catholic University of Pernambuco Recife 51110-200 Brazil

The paper discussed about the staged construction analysis of two-span precast-girder bridge considering time dependent effects, namely creep and aging of concrete. Results obtained showed that it is very important to consider construction stage in the analysis of bridge because of stress resultants which are important in design process and very different from those obtained without the consideration of construction stage. This fact is especially important for bridges, because construction period continues along time and loads may change during the construction period and after.

关键词： Staged construction analysis reinforced concrete bridge.

Evaluation of Reinforced Concrete Structures with Views for Rehabilitation

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Journal of Civil Engineering and Architecture 2016年第1期10卷 72-80页

作者： Jackline de Assis Lopes S. Oliveira romildo Alves Berenguer Lydia Barreto Eliana Cristina Barreto Monteiro Romilde Almeida de Oliveira Department of Civil Engineering Catholic University of Pernambuco Recife 51110-200 Brazil Department of Civil Engineering University of Pernambuco Recife 51110-200 Brazil

The increasing number of pathological occurrences is found in reinforced concrete structures, so does the demand for inspection and maintenance services in residential communities in the state of Pernambuco, which aim to detect damage to the structure in a timely manner to minimize repair costs, thus applying preventive maintenance in order to guarantee the estimated useful life of the project for the building. However, it is observed that the practice of periodic inspections is not yet part of the culture of a certain segment of the population that does not have economic means and knowledge of the importance of maintenance to ensure the integrity of the structure. It was used in this work an inspection script with use of tests and methodology to quantify damage and to check the state of degradation of two residential buildings with more than 20 years and built near the seafront where environmental aggression is strong. The deterioration found in each of the buildings has been differentiated due to different corrective maintenance performed at every building. The last maintenance, performed in Building A, was performed by corrective hand of unskilled labour guided by the community itself, which has no expertise in the field of civil engineering. In Building B, the situation is similar, compounded by the opinion of some tenants that there is no need for this routine, even the structure being in critical condition, as was confirmed with the application of the methodology employ. There should be a legislation that governs the execution of inspections and maintenance programs in addition to the existing technical standards. The methodologies presented suitable for checking the degree of degradation of the structures and performed tests confirmed the diagnosis obtained by visual inspection and quantification of damage.

关键词： Pathology inspection maintenance lifespan concrete.

Deformation Analysis Due to Early Loading of Concrete Buildings

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Journal of Civil Engineering and Architecture 2016年第6期10卷 690-695页

作者： romildo Alves Berenguer Fernando Artur Nogueira Silva Joao Luiz de Melo Ramos Fabio Cameiro Lourenco Pryscylla Femanda Silva Chaves Ana Cecilia Ferreira Leite Department of Civil Engineering Catholic University of Pernambuco Recife 51110-200 Brazil

The building industry has experienced in recent years a strong growth in demand in general and in the case of reinforced concrete buildings this increase has been more marked. This fact has also contributed to accelerate all stages of the production process of these constructions with more pronounced effects on the methodologies used in the constructive steps that influence directly the structural design of the building. Structures loaded at ever earlier ages, in which the strength and deformation properties of materials are not yet sufficiently mature. It is a variable that needs to be taken into account already in the design phase so that the concrete structure behaves within acceptable level of reliability taking into account design code recommendations for service life. To understand the importance of constructive effects and to assess its magnitude in the execution of reinforced concrete buildings, this paper presents result from nonlinear analyses using finite element method adopting an approach commonly referred as staged construction applied to a typical building found in the practice. The effects of creep and shrinkage were considered and the results obtained demonstrate that the strains due to constructive effects can, in certain cases, assume representative values which, if ignored, can lead to important pathologies in the building.

关键词： Reinforced concrete buildings constructive effects staged construction creep shrinkage.

Analysis of a Concrete Structure that Was Exposed to Fires in the Metropolitan Region of Recife

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Journal of Civil Engineering and Architecture 2016年第3期10卷 344-352页

作者： romildo Alves Berenguer Adauto de Holanda Barbosa Eliana Cristina Barreto Monteiro Romilde Almeidade Oliveira Angelo Just da Costa e Silva Department of Civil Engineering Catholic University of Pernambuco Recife 51110-200 Brazil Department of Civil Engineering University of Pernambuco Recife 51110-200 Brazil

In large cities, news about fires in buildings are powered by problems such as old wiring and no maintenance. Accidents with chemicals and human error, which when added to the different characteristics of each fire and structures can generate the factors causing these disasters. The gradual rise in temperature causes a different effect in mortar and concrete parts, verifying the change in coloring provided to loss of mechanical strength and surface crumbling, cracking and disintegration of the structure itself. This paper presents a case study in which a building that is located in the metropolitan region of Recife was exposed to a fire situation. The metropolitan region of Recife is composed of several old buildings that by virtue of their age may have delayed construction methods, and may expose the fragility of the concrete used in its construction on a fire situation. The concrete structures are recognized by the good resistance to fire because of the thermal characteristics of the material, however, the temperature rise in the concrete elements in characteristic causes a reduction in strength and modulus of elasticity of the material, the loss in stiffness leading to polyphase degradation of reinforced concrete, structural parts can lead to ruin, but when properly sized and executed, the concrete can serve as a proactive agent to be exposed to high temperatures, as the same may be subjected to high temperatures accidentally or they may be part of their normal work.

关键词： Awning pathological manifestations durability