Mohammed Kishk

Wind Turbine Maintenance Optimisation: principles of quantitative maintenance optimisation

Maintenance optimisation is a crucial issue for industries that utilise physical assets due to its impact on costs, risks and performance. Current quantitative maintenance optimisation techniques include Modelling System Failures MSF (using monte-carlo simulation) and Delay-Time Maintenance Model (DTMM). The MSF investigates equipment failure patterns by using failure distribution, resource availability and spare-holdings to determine optimum maintenance requirements. The DTMM approach examines equipment failure patterns by considering failure consequences, inspection costs and the period to determine optimum inspection intervals. This paper discusses the concept, relevance and applicability of the MSF and DTMM techniques to the wind energy industry. Institutional consideration as well as the benefits of practical implementation of the techniques are highlighted and discussed.

The Selection of a Suitable Maintenance Strategy for Wind Turbines

Common maintenance strategies applied to wind turbines include ‘Time-Based’ which involves carrying out maintenance tasks at predetermined regular-intervals and ‘Failure-Based’ which entails using a wind turbine until it fails. However, the consequence of failure of critical components limits the adequacy of these strategies to support the current commercial drivers of the wind industry. Reliability-Centred Maintenance (RCM) is a technique used mostly to select appropriate maintenance strategies for physical assets. In this paper, a hybrid of an RCM approach and Asset Life-Cycle Analysis technique is applied to Horizontal-Axis Wind Turbines to identify possible failure modes, causes and the resultant effects on system operation. The failure consequences of critical components are evaluated and expressed in financial terms. Suitable Condition-Based Maintenance activities are identified and assessed over the life-cycle of wind turbines to maximise the return on investment in wind farms.

Combining various facets of uncertainty in whole‐life cost modelling

Estimates for various parameters in a whole‐life costing (WLC) exercise are obtained from different sources each with its own level and type of uncertainty. A practical procedure is developed to handle statistically significant data and expert assessments within the same whole‐life costing (WLC) model calculation. First, various methods used to combine random and subjective data are critically reviewed with emphasis on their suitability to WLC modelling. This is followed by the identification of an appropriate mathematical framework into which all information and data are transformed to a common representation making their integration a straightforward task. The proposed procedure is then implemented into a computational algorithm. The efficacy of the algorithm is explained in the context of a selected example application.

Modelling System Failures to Optimise Wind Turbine Maintenance

Modelling System Failures (MSF) is a unique quantitative maintenance optimisation technique which permits the evaluation of life-data samples and enables the design and simulation of the systems model to determine optimum maintenance activities. In this paper, the approach of MSF is used to assess the failure characteristics of a horizontal axis wind turbine. Field failure data are collated and analysed using the Maximum Likelihood Estimation in the Weibull Distribution; hence shape (β) and scale (η) parameters are estimated for critical components and subsystems of the wind turbine. Reliability Block Diagrams are designed to model the failures of the wind turbine and of a selected wind farm. The models are simulated to assess the reliability, availability and maintainability of the wind turbine and the farm; taking into account the costs and availability of maintenance crew and spares holding. Optimal maintenance activities are determined to minimise the total life-cycle cost of the wind farm.

An Investigation into the Risk of Construction Projects Delays in the UAE

The growing rate of delays in project delivery is considered a major criticism of the construction companies in the United Arab Emirates UAE. This paper aims to investigate the causes and effects behind the delays pertaining to delivery of construction projects in the UAE. The study is exploratory in nature, and incorporates a pilot questionnaire survey and interviews. An extensive literature review indicates potential factors that have possible effects on construction completion delay. The questionnaire forms were sent to 50 construction companies. Thirty-five 70% completed responses were received. Analysis of the survey data has revealed that about 42 potential causes and effects of delay relate to various groups of stakeholders. The results show the top fifteen factors relate to clients, project managers and finance aspects. It was found that cost and time overruns are the most significant effects. These results are in partial agreement with previous studies. The paper argues that the key determinant in ensuring project control is on-time project delivery. The results of the study can provide moderate support for a suggested hypothesis, through a framework of project success factors. It should be of high concern to knowledge managers in various roles and decision-makers.

Assessing risk response maturity

Purpose – The aim of the research work that underpins this paper is, therefore, to examine the effectiveness of project management maturity in mitigation measures for risk response within construction companies to influence project success. Design/methodology/approach – Ninety-three questionnaires were collected from respondents in different construction companies in the UAE, in order to assess project maturity in construction projects. Fifteen key success factors emerged from the literature and the questionnaire survey as being susceptible to improvement with increasing the project success. Findings – The results reveal that maturity can be improved by developing mitigation measures which positively influence risk response for project success. Based on these results, a framework is proposed to improve the practical functioning of risk response. Research limitations/implications – This study, however, reflects the general view but for greater confirmation, in-depth investigation is required, and the sugge...

A structured model for performance assessment in property management

Property performance assessment has become increasingly important in property management because of the emergence of a number of trends as issues of concern of property owners and occupiers. There are, however, many problems facing the consideration of performance measurement. Perhaps the main obstacle is the lack of a structured process for property performance measurement. The prime objective of the research work that underpins this paper therefore is to address this gap by the development of a structured model for property performance measurement. This involved three main steps. First, basic characteristics of an effective performance assessment in property managements are identified and the framework for a generic model is outlined. Next, key processes of performance measurement and property management tasks are identified. Then, these processes are set out into steps for better understanding and applicability of the model to actual property management practices. Some unique features of the model include consideration of clients and tenants requirements, integration of the functions of property management in the model and the inclusion of two property and resource databases to aid storage and retrieval of information. Besides, it is the first step in developing a dedicated computer tool for property performance assessment.

Models for Sustainable Electricity Provision in Rural Areas Using Renewable Energy Technologies - Nigeria Case Study

Sustainable electricity generation and supply in Nigeria has been a perennial challenge even though the country is one of the world’s leading exporters of oil and a member of organisation of petroleum exporting countries (OPEC). The reasons for this problem include persistent vandalism of energy infrastructure, high cost of gridline network and weak transmission, and distribution facilities. Existing capacity only provides electricity to 34% and 10% of urban centres and rural areas, respectively. Decentralised renewable energy technologies (RETs) may be a sustainable and economical alternative for meeting electricity demands of the rural communities representing two-thirds of the total country’s population. This research thus investigates alternative RETs that may provide sustainable electricity to Nigerian rural areas. Interview method was used. The findings reveal that the most suitable RETs in order of priority are biomass, solar PV, small hydropower, solar thermal, and wind energy systems. In addition, biomass energy systems (BES) being the most selected, has been subjected to further investigation; unlike the national energy policy under representation of BES, 77% of the interviewees agreed that BES utilisation in the country’s rural areas are suitable and desirable. Also, for implementation of BES, all the identified drivers and enablers should be taken into consideration. However, some identified constraints to adoption and development of BES include supply chain limitation, substantial land, and water requirements for set-up and processing. Thus, this study recommends that the existing rural areas energy policies be reviewed.