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Article
Publication date: 20 June 2008

Bilsen Beşergil, M. Sabih Özer, Mustafa Eskici and Enver Atik

This paper aims to determine the usage time of the test lubricant N0, prepared from base oils of Aliaga Plant, Izmir, in gasoline and diesel‐engines, and the…

Abstract

Purpose

This paper aims to determine the usage time of the test lubricant N0, prepared from base oils of Aliaga Plant, Izmir, in gasoline and diesel‐engines, and the investigations of high‐temperature oxidation, engine‐protective properties, and property changes of the lubricant in performance time.

Design/methodology/approach

Physical and chemical properties of the lubricating oil were initially established, and the oil was then subjected to Petter W‐1 gasoline and Petter AV‐1 diesel test engines. Dismantling of the engine parts was followed by the examination of pistons, piston rings and bearings, and analysis of the lubricant was also undertaken. The engine performance test results and the quality control of the lubricating oil assessments were evaluated according to the International Engine Lubricant Specifications.

Findings

The lubricating oil, under sluggish experimental conditions, appears to meet a 40‐hour test in gasoline engines and a 120‐hour test in diesel engines with the specifications. This means that under usual working conditions the lubricants keep the engine protective properties in 7,000 km distance for gasoline run‐vehicles, and in 5,000 km distance for diesel run‐vehicles, after which change of the oil is required.

Originality/value

The paper provides information of value to those involved with lubrication and engine performance.

Details

Industrial Lubrication and Tribology, vol. 60 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

Content available
Article
Publication date: 24 October 2008

Abstract

Details

Journal of Manufacturing Technology Management, vol. 19 no. 8
Type: Research Article
ISSN: 1741-038X

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Article
Publication date: 13 August 2018

Sami Elferik, Mohammed Hassan and Mustafa AL-Naser

The purpose of this paper is to improve the performance of control loop suffering from control valve stiction. Control valve stiction is considered as of one of the main…

Abstract

Purpose

The purpose of this paper is to improve the performance of control loop suffering from control valve stiction. Control valve stiction is considered as of one of the main causes of oscillation in process variables, which require performing costly unplanned maintenance and process shutdown. An adaptive solution to handle valve stiction while maintaining safety and quality until next planned maintenance is highly desirable to save considerable cost and effort.

Design/methodology/approach

This paper implements a new stiction compensation method built using adaptive inverse model techniques and intelligent control theories. Finite impulse response (FIR) model, which is known to be robust, as a compensator for stiction. The parameters of FIR model are tuned in an adaptive way using differential evolution (DE) technique. The performance of proposed method is compared with other two compensation techniques.

Findings

The new method showed excellent performance of the DE–FIR compensator compared to other dynamic inversion methods in terms of minimizing process variability, energy saving and valve stem aggressiveness.

Research limitations/implications

The compensation ability for all compensators reduces with the increase of stiction severity, thus the over shoot case always shows the worst result. In future works, other optimization techniques will be explored to find the appropriate technique that can extend the FIR model size with smallest computation time that can improve the performance of the compensator in over shoot case. In addition, the estimation of the valve residual life based on the level of stiction and effort required by the controller should be considered.

Originality/value

The presented approach represents an original contribution to the literature. It performs stiction compensation without a need for a prior knowledge on the process or the valve models and guarantees a smooth control of the stem movement with a low control effort. The proposed approach differs from previous adaptive methods as it uses stable FIR models and DE to find the appropriate parameters of the inverse model and handle nonlinear behavior of stiction.

Details

Journal of Quality in Maintenance Engineering, vol. 24 no. 3
Type: Research Article
ISSN: 1355-2511

Keywords

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Article
Publication date: 15 June 2021

Qianyun Zhang, Julie M. Vandenbossche and Amir H. Alavi

Unbonded concrete overlays (UBOLs) are commonly used in pavement rehabilitation. The current models included in the Mechanistic-Empirical Pavement Design Guide cannot…

Abstract

Purpose

Unbonded concrete overlays (UBOLs) are commonly used in pavement rehabilitation. The current models included in the Mechanistic-Empirical Pavement Design Guide cannot properly predict the structural response of UBOLs. In this paper, a multigene genetic programming (MGGP) approach is proposed to derive new prediction models for the UBOLs response to temperature loading.

Design/methodology/approach

MGGP is a promising variant of evolutionary computation capable of developing highly nonlinear explicit models for characterizing complex engineering problems. The proposed UBOL response models are formulated in terms of several influencing parameters including joint spacing, radius of relative stiffness, temperature gradient and adjusted load/pavement weight ratio. Furthermore, linear regression models are developed to benchmark the MGGP models.

Findings

The derived design equations accurately characterize the UBOLs response under temperature loading and remarkably outperform the regression models. The conducted parametric analysis implies the efficiency of the MGGP-based model in capturing the underlying physical behavior of the UBOLs response to temperature loading. Based on the results, the proposed models can be reliably deployed for design purposes.

Originality/value

A challenge in the design of UBOLs is that their interlayer effects have not been directly considered in previous design procedures. To achieve better performance predictions, it is necessary to capture the effect of the interlayer in the design process. This study addresses this important issue via developing new models that can efficiently account for the effects of interlayer on the stress and deflections. In addition, it provides an insight into the effect of several parameters influencing the deflections of the UBOLs. From a computing perspective, a powerful evolutionary computation technique is introduced that overcomes the shortcomings of existing machine learning methods.

Details

Engineering Computations, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0264-4401

Keywords

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Article
Publication date: 1 June 2019

Dijana Alic

On 6 april 1992, the european union (eu) recognised bosnia and hercegovina as a new independent state, no longer a part of the socialist federal republic of Yugoslavia…

Abstract

On 6 april 1992, the european union (eu) recognised bosnia and hercegovina as a new independent state, no longer a part of the socialist federal republic of Yugoslavia. The event marked the start of the siege of sarajevo, which lasted nearly four years, until late february 1996. It became the longest siege in the history of modern warfare, outlasting the leningrad enclosure by a year. During its 1425 days, more than 11,500 people were killed. The attacks left a trail of destruction across the city, which began to transform it in ways not experienced before.

This paper explores how the physical transformation of sarajevo affected the ways in which meaning and significance were assigned to its built fabric. I argue that the changes imposed by war and the daily destruction of the city challenged long-established relationships between the built fabric and those who inhabited the city, introducing new modes of thinking and interpreting the city. Loosely placing the discussion within the framework of ‘Thirdspace', established by urban theorist and cultural geographer edward soja, i discuss the relationship that emerged between the historicality, sociality and spatiality of war-torn sarajevo.

Whether responding to the impacts of physical destruction or dramatic social change, the nexus of time, space and being shows that the concept of spatiality is essential to comprehending the world and to adjusting to and resisting the impact of extraordinary circumstances. Recognising the continuation of daily life as essential to survival sheds light on processes of renewal and change in a war-affected landscape. These shattered urban spaces also show the ways in which people make a sense of place in relation to specific socio-historical environments and political contexts.

Details

Open House International, vol. 44 no. 2
Type: Research Article
ISSN: 0168-2601

Keywords

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Article
Publication date: 31 December 2020

Risha Fayyaz, Fasih Ali Ahmed, Adeel Abid, Afshan Akhtar, Rabail Jarwar, Anila Jasmine, Sameer Ahmad Khan, Shahira Shahid, Iraj Khan, Aneeq Muhammad Yousuf and Imtiaz Jehan

This study aims to assess the quality of care among adult oncology patients in tertiary care hospitals in Karachi by using an international standard of quality of care and…

Abstract

Purpose

This study aims to assess the quality of care among adult oncology patients in tertiary care hospitals in Karachi by using an international standard of quality of care and to identify domains where improvement is needed.

Design/methodology/approach

This is a cross-sectional study carried out at two tertiary care hospitals of Karachi, Pakistan, belonging to private and public sector, respectively, between February and April 2018. Face-to-face interviews were conducted using a modified questionnaire having five-point Likert scale questions regarding satisfaction of patients with doctors, nursing staff, information provided and the hospital standards. SPSS 20 was used for statistical analysis, and the results were expressed using mean, frequencies, percentages and p-values.

Findings

The authors approached 415 patients, out of which 389 patients agreed to participate in the study. For both hospitals, the lowest mean scores were for sections pertaining to satisfaction with psychosocial support and information provided. The mean satisfaction score of patients from the private hospital were found to be significantly higher as compared to patients from the public hospital for all domains of patient care (p-value < 0.01 using t-test for two independent samples). The data showed an increasing trend of “satisfied” responses as the household income increased.

Research limitations/implications

A comparative study should be conducted with the aim of pinpointing the differences in areas in which there is a significant difference in positive satisfaction levels between private and public sectors. Similar research could also be expanded adding other variables that affect quality of care such as doctor's approach to their patients, time given during each consultation and patient's understanding of doctor's knowledge. Further studies can be done to bridge the gaps between what a doctor views as standard care and what the patient knows will help them receive a more holistic approach to care.

Practical implications

Assessing the quality of care helps determine gaps in care and allocating health resources accordingly. In clinical practice, emphasis needs to be given on increased duration and improved quality of patient counselling to improve the low satisfaction levels of patients regarding the psychosocial support. Addressing patients' concerns should be made part of clinical teaching from an undergraduate level. As far as patient access to doctors of the specific speciality is concerned, hospital managements should adopt systems to ensure continuum of care and come up with mechanisms to bridge the discrepancy between a patient's needs and doctor availability.

Social implications

After being identified as a major deficiency, training doctors in the sensitivities of the population and demographics, especially with respect to socio-economic statuses, can aid in enhancing patient satisfaction to the treatment. Implementation of patient-centred care leads to greater satisfaction with care, which, in turn, increases a patient's self efficacy in managing important aspects of their care and improves health care-related quality of life.

Originality/value

Cancer patients have long-term exposure to the hospital environment. A patient's satisfaction with the quality of care is an important determinant in patient compliance to the treatment protocol and required hospital visits. There is a dearth of research on the outpatient quality of care in the oncology departments in Karachi. This study provides an overview of the quality of care available to cancer patients in Karachi both in public and private sectors. The results of our study identify the gaps in the quality of care being provided to the patients in a developing country like Pakistan, which can be used to improve the quality of care, leading to better patient outcomes.

Details

International Journal of Health Care Quality Assurance, vol. 34 no. 1
Type: Research Article
ISSN: 0952-6862

Keywords

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Article
Publication date: 8 December 2020

Sohni Siddiqui, Anjum Bano Kazmi and Zahid Ahmed

Aggression is an undesirable behavior that assaults traditions norms, morals and standards of ethics practiced in society. To address the scarceness of identification…

Abstract

Purpose

Aggression is an undesirable behavior that assaults traditions norms, morals and standards of ethics practiced in society. To address the scarceness of identification tools and for evidence-based interventions in Pakistan, the purpose of this study is to determine the extent to which aggression is prevalent in Pakistan’s people by newly developed self-reported questionnaires in the Urdu language designed after reviewing the cultural and social perspectives of the society.

Design/methodology/approach

The research design was based on principles of scale development followed by exploratory and confirmatory factor analysis. A subject matter expert panel technique was adopted where educationists from diversified backgrounds helped to generate items and to establish content validity.

Findings

The three-factor construct has been supported by factor analysis. These analyzes identified aggression measures in terms of direct aggression, displaced aggression and indirect aggression. The model has established inner consistency, reliability and validity. Furthermore, the impact of age and gender on different forms of aggression was explored and discussed.

Originality/value

Aggression is a distinctive trait of many psychiatric disturbances. To undertake the dearth of identification tools and for evidence-based interventions in Pakistan, it was necessary to develop a tool for identification to address aggression issues among common people. This research is devised to develop a self-reported questionnaire in the Urdu language keeping cultural and social perspectives of society.

Details

Journal of Aggression, Conflict and Peace Research, vol. 13 no. 1
Type: Research Article
ISSN: 1759-6599

Keywords

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