Volume 11, Issue 2, March 2020

Suitability of Multi-Layer Polymeric Coating for Protection of Offshore Pipelines and Structures

Alonge David Shola, Tobinson A. Briggs

Offhore Technology Institute, University of Port Harcourt, Nigeria
Department of Mechanical Engineering, University of Port Harcourt, Nigeria

Abstract- Offshore pipelines or structures are subjected to accidental impact loads, especially impact loads from trawl gear, anchors from the vessel, which can destroy the pipeline or structure. Study shows that polymeric coating solutions, having the ability to absorb energy, which is the major focus of the investigation. This study set to model and simulate multi-layer polymeric coating for the protection of offshore steel X65 pipe. The polymer coating can be applied to the pipes to help in their protection against corrosion along with thermal insulation. Standard design codes, Coatings are conservatively assumed when determining the energy absorbed by structures during impact which is taken to be conservative. However, the energy absorbed can also be overly conservative in the protection of such structure. To this end, modelling and simulation of a common offshore steel pipe are performed, using a polymer composite coating. The primary purpose of this study is to investigate the deformation and protection of a typical polymeric coated pipe by energy absorbed procedure during impact on it. The result shows that pipe with the polymeric coating is more protected compared to the pipeline without composite coating.

Keywords- Impact Load, Polymeric Coating, Deformation Analysis and Steel X65 Pipe

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On the Correlation of Both Vibration and Cutting Forces with the Roughness of the Workpiece Machined Surface During Turning

Mohammed W. Alhazi

Mechanical Engineering Department, College of Engineering & Islamic Architecture

Abstract- Cutting forces and vibration of the machine tools were always subject of several works during the last few decades. In the present work, new correlation between the main cutting force and vibration with the undeformed chip cross section, during machining process of CNC turning machine, were established. Several types of workpiece materials, i.e., commercial aluminum, brass, bronze, stainless steel and carbon steel, were used during the machining process and both the principal cutting force and the vibrations at different locations were recorded. The roughness of the machined workpieces were also measured and attempts were conducted to analysis the collected data

Keywords- Cutting Forces, Roughness, Turning Process and Vibration

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Concrete Mixture with use of Iron Powder Waste for Coarse Aggregate Doping

Renan Dias, Sherington Bigotto, Daniel Ukuessunga Benjamim, Denise Luisa Chotolli, Matheus Viana de Souza

Programa de Pós Graduacao em Engenharia Civil - PPGEC, Faculdade de Engenharia de Ilha Solteira, Universidade Estadual Paulista "Julio de Mesquita Filho" - FEIS/UNESP

Abstract- The high consumption of concrete in construction, coupled with the environmental impacts resulting from the extraction of raw material for its manufacture, fosters innovation and ideas for its improvement. In order to optimize its resistance to stresses, as well as durability and dimensional stability, the aggregate doping technique was developed with the purpose of improving low quality aggregates, as well as optimizing those with good mechanical properties. Using the iron residue - iron powder - to perform the process, the doping proposes, besides an improvement in the concrete properties, a microstructural analysis in the interfacial transition zone (ITZ) of the paste and aggregate interface, where the first cracks of the material occur, due to mechanical stress. For this purpose, the focus was on comparing specimens tests at 28 days with and without doped aggregate, comparing results of diametrical compression, and modulus of elasticity. Regarding the compression tests, there was a significant increase in the diametral and axial compression; it was observed compatible values between the modulus of elasticity calculated based on the Brazilian standard and those obtained experimentally.

Keywords- Aggregate Doping, Concrete, Mechanical Testes and Iron Powder Waste

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Lie Symmetry Analysis of Modified Diffusive Predator-prey Competition System of Equations

Odhiambo Francis, T. J. O. Aminer, M. E. Oduor Okoya

School of Mathematics and Actuarial Science, Jaramogi Oginga Odinga University of Science and Technology, P.O. Box 210-40601, Bondo, Kenya

Abstract- The predator-prey equations were developed and used by Lotka and Volterra to analyze the dynamics of biological systems in which two species interact, one as a predator and the other as prey [3]. Several attempts have been made in finding the exact solutions of these models using both numerical and analytical techniques [5]. Lie symmetry analysis has had applications in solving mathematical models involving non-linear differential equations; both ordinary and partial. In this paper, we have solved a modified diffusive predator-prey competition model of the form: ut - uxx - u + u2 + 2 uv = 0, and vt - vxx - av + av2 + 3auv = 0; using Lie symmetry approach and obtained its general symmetry solutions. This method makes use of generator, prolongations, infinitesimal generators, symmetries and invariant solutions. The solutions obtained may be used to describe the long-term growth or decline of species in an ecosystem.

Keywords- Symmetries, Generators, Prolongations, Lie Group Theory, Predator-prey Equations, Invariant and Symmetry Solutions

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Evaluation of Maintenance Management Strategy for Oil Field Equipment: A Case Study of Wireline Pressure Testers

Efe S. Agbamu and Tobinson A. Briggs

University of Port Harcourt

Abstract- Maintenance management strategy has been an important tool in oil servicing firms. Presently, the oil servicing firms in south-south Nigeria are faced with the challenges of choosing the best and suitable approach in implementing maintenance management strategy as a tool for improving equipment performance. The research work deployed a sectional survey of two oil servicing firms in Port Harcourt, namely Company X and Company Y, respectively. A target population of 1847 staff of the firm were enlisted, and then further streamlined to 194 maintenance management staff. The primary data was collated through a structured questionnaire and analyzed using descriptive statistics. A stratified purposive sampling with a sample size of 135 was used to select both senior and junior staff of both firms for analysis. The outcome of the research findings revealed that there is a similarity in the maintenance management strategy activities of Company X and Company Y. Firstly, the Study revealed that Company X uses a combination of reliability centred maintenance, preventive maintenance and corrective maintenance program. At the same time, the management of Company Y practices preventive and corrective maintenance programs. Also observed are the challenges in the quest to implement the maintenance strategies. These challenges highlighted by the respondents are: maintenance personnel, tools and materials, and maintenance/operation disturbance are the major maintenance problems faced. The study recommends that management in both oil servicing firms need to practice effective maintenance management policies and increase human (skilled personnel) capital development.

Keywords- Maintenance Strategy, Tool Management, Maintenance Implementation and Equipment Performance

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