Open-loop unstable systems with time-delays are often encountered in process industry, which are often more difficult to control than stable processes. In this paper, the stabilization by PID controller of second-order unstable processes, which can be represented as second-order deadtime with an unstable pole (SODUP) and second-order deadtime with two unstable poles (SODTUP), is performed via the necessary and sufficient criteria of Routh-Hurwitz stability analysis. The stability analysis provides improved understanding on the existence of a stabilizing range of each PID parameter. Three simple PID tuning algorithms are proposed to provide desired closed-loop performance-robustness within the stable regions of controller parameters obtained via the stability analysis. The proposed PID controllers show improved performance over those derived via some existing methods.
The cumulative sum (CUSUM) control chart is widely used in industry for the detection of small and moderate shifts in process location and dispersion. For efficient monitoring of process variability, we present several CUSUM control charts for monitoring changes in standard deviation of a normal process. The newly developed control charts based on well-structured sampling techniques - extreme ranked set sampling, extreme double ranked set sampling and double extreme ranked set sampling, have significantly enhanced CUSUM chart ability to detect a wide range of shifts in process variability. The relative performances of the proposed CUSUM scale charts are evaluated in terms of the average run length (ARL) and standard deviation of run length, for point shift in variability. Moreover, for overall performance, we implore the use of the average ratio ARL and average extra quadratic loss. A comparison of the proposed CUSUM control charts with the classical CUSUM R chart, the classical CUSUM S chart, the fast initial response (FIR) CUSUM R chart, the FIR CUSUM S chart, the ranked set sampling (RSS) based CUSUM R chart and the RSS based CUSUM S chart, among others, are presented. An illustrative example using real dataset is given to demonstrate the practicability of the application of the proposed schemes.
A monitoring procedure was introduced for process variability in a multivariate setting based on individual observations which was a combination of (i) robust high breakdown point approach in the set-up stage to determine the reference sample and (ii) the use of Wilks chart in the mass production stage. This setting is what the Malaysian manufacturing industry is currently lacking in, especially when a robust approach must be used. The advantage of this procedure was revealed by using the case of a female shrouded connector production process in a Malaysian industry. Moreover, this procedure could also be used in any process quality monitoring and for any industry. A recommendation for quality practitioners was also addressed.
Matched MeSH terms: Industry; Manufacturing Industry
Successful implementation of the lean concept as a sustainable approach in the construction industry requires the identification of critical drivers in lean construction. Despite this significance, the number of in-depth studies toward understanding the considerable drivers of lean construction implementation is quite limited. There is also a shortage of methodologies for identifying key drivers. To address these challenges, this paper presents a list of all essential drivers within three aspects of sustainability (social, economic, and environmental) and proposes a novel methodology to rank the drivers and identify the key drivers for successful and sustainable lean construction implementation. In this regard, the entropy weighted Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) was employed in this research. Subsequently, an empirical study was conducted within the Malaysian construction industry to demonstrate the proposed method. Moreover, sensitivity analysis and comparison with the existing method were engaged to validate the stability and accuracy of the achieved results. The significant results obtained in this study are as follows: presenting, verifying and ranking of 63 important drivers; identifying 22 key drivers; proposing an MCDM model of key drivers. The outcomes show that the proposed method in this study is an effective and accurate tool that could help managers make better decisions.
The expanding global Muslim population has increased the demand for halal pharmaceuticals. However, there are several challenges for this emerging niche industry, foremost of which is the need to establish a proper, well-regulated, and harmonized accreditation and halal management system.
Matched MeSH terms: Drug Industry/standards; Drug Industry/ethics*
Growing environmental deterioration has caused many countries to tighten their environmental regulations across the globe. Recent studies show that most developed countries enforced stricter environmental regulations creating a pollution haven to developing countries such as Nigeria. Studies show the non-availability of an environmental regulation compliance scale in the energy sectors. The aim of this paper is to validate the effects of environmental regulation compliance scale for oil and gas companies' operations in the Nigerian oil and gas industry. Hence, an adapted questionnaire comprising 11 items was administered to 300 local and multinational oil and gas companies in Nigeria. All the items were subjected to evaluations and validations by eight expert reviewers with cognate experience in oil and gas activities. Evaluation of the reliability and validity of the measures of the environmental regulation scale was performed through confirmatory factor analysis (CFA) using SPSS version 25 and PLS-SEM version 3.8. The results provide evidence that the environmental regulation compliance scale has met the reliability and validity criteria. Consequently, policymakers, practitioners, and researchers can adapt this scale to assess the effects of environmental regulation compliance by companies in different jurisdictions across the globe. This study undoubtedly builds the existing literature and contributes to the subject area; by implication, the validated scale will assist host oil and gas countries with stringent environmental regulations to come up with policies in such a way as to ensure not chasing away the current investors or discouraging prospective ones from investing in their countries.
Matched MeSH terms: Oil and Gas Industry*; Industry*
Fused deposition modelling (FDM) opens new ways across the industries and helps to produce complex products, yielding a prototype or finished product. However, it should be noted that the final products need high surface quality due to their better mechanical properties. The main purpose of this research was to determine the influence of computer numerical control (CNC) machining on the surface quality and identify the average surface roughness (Ra) and average peak to valley height (Rz) when the specimens were printed and machined in various build orientations. In this study, the study samples were printed and machined to investigate the effects of machining on FDM products and generate a surface comparison between the two processes. In particular, the block and complex specimens were printed in different build orientations, whereby other parameters were kept constant to understand the effects of orientation on surface smoothness. As a result, wide-ranging values of Ra and Rz were found in both processes for each profile due to their different features. The Ra values for the block samples, printed samples, and machined samples were 21, 91, and 52, respectively, whereas the Rz values were identical to Ra values in all samples. These results indicated that the horizontal surface roughness yielded the best quality compared to the perpendicular and vertical specimens. Moreover, machining was found to show a great influence on thermoplastics in which the surfaces became smooth in the machined samples. In brief, this research showed that build orientation had a great effect on the surface texture for both processes.
This paper proposed seven existing and new performance indicators to measure the effectiveness of quality management system (QMS) maintenance and practices in construction industry. This research is carried out with a questionnaire based on QMS variables which are extracted from literature review and project performance indicators which are established from project management's theory. Data collected was analyzed using correlation and regression analysis. The findings indicate that client satisfaction and time variance have positive and significant relationship with QMS while other project performance indicators do not show significant results. Further studies can use the same project performance indicators to study the effectiveness of QMS in different sampling area to improve the generalizability of the findings.
The combination of irradiation and biological technique was chosen to study COD, BOD5 and colour removal from textiles effluent in the presence of food industry wastewater. Two biological treatments, the first consisting a mix of non irradiated textile and food industry wastewater and the second a mix of irradiated textiles wastewater and food industry wastewater were operated in parallel. Reduction percentage of COD in textiles wastewater increased from 29.4% after radiation to 62.4% after further undergoing biological treatment. After irradiation, the BOD5 of textiles wastewater was reduced by 22.1%, but reverted to the original value of 36mg/1 after undergoing biological treatment. Colour had decreased from 899.5 ADMI to 379.3 ADM1 after irradiation and continued to decrease to 109.3 ADMI after passing through biological treatment.
Matched MeSH terms: Food-Processing Industry; Food Industry
This study investigates the impact of the aggregate and individual dimensions of environmental performance (EP) on financial performance (FP), based on a dataset covering the travel and tourism industry (airlines, casinos, hotels, and restaurants) across different economic regions over the period 2003-2014. The results reveal that EP positively affects the FP in the hotel industry when aggregate EP is used. When individual dimensions of EP are considered, resource reduction is found to positively (negatively) affect the performance in the hotel (airline) industry, while product innovation positively affects the performance in the restaurant industry. Hence, the trade-off effect seems to be dominant in the airline industry, and the 'heterogeneous resources and reputation-building' hypothesis is evident in both the hotel and restaurant industries. In addition, in general, the findings support the positive moderating effect of slack resources on the relationship between the individual dimensions of EP and FP in the travel and tourism industry, and, hence, are supportive of the slack resources hypothesis. These effects, however, vary depending on the travel and tourism industry under investigation.
This paper investigates the efficiency and total factor productivity (TFP) growth of the Pakistani banking industry and determines the impact of risk and competition on the efficiency and TFP growth. The data envelopment analysis (DEA)-based Malmquist productivity index is used to measure efficiency and TFP growth of the Pakistani banking industry. The generalized method of moments (GMM) model is applied to observe the impact of risk and competition on efficiency and TFP growth. The motivation behind the use of GMM model is its ability to overcome unobserved heterogeneity, autocorrelation, and endogeneity issues. The results of the study show that the credit and liquidity risks have positive while insolvency risk has negative effect on the efficiency and TFP growth. The competition leads to improve technological efficiency but declines the technical efficiency growth. Among other explanatory variables, operational cost management, banking sector development, GDP growth rate, and infrastructure development show significant relationships with various efficiencies and TFP growth. The banks also facilitate for the purchase of carbon-intensive products in order to reduce carbon emissions. Strong banking development successfully allocate their financial resources for the development of energy-efficient technology while banking sector development is found to be negatively related with environmental sustainability. The strong banking sector possesses a significant negative influence on carbon reduction and environmental degradation.
Digital technologies (DTs) are proven helpful in the Architecture, Engineering and Construction (AEC) industry due to their varied benefits to project stakeholders, such as enhanced visualization, better data sharing, reduction in building waste, increased productivity, sustainable performance and safety improvement. Therefore, researchers have conducted various studies on DTs in the AEC industry over the year; however, this study explores the state-of-the-art research on DTs in the AEC industry by means of a bibliometric-qualitative review method. This research would uncover new knowledge gaps and practical needs in the domain of DTs in the AEC industry. In addition, bibliometric analysis was carried out by utilizing academic publications from Scopus (i.e., 11,047 publications for the AEC industry, 1956 for DTs and 1778 for DTs in the AEC industry). Furthermore, a qualitative review was further conducted on 200 screened selected research publications in the domain of DTs. This study brings attention to the body of knowledge by envisioning trends and patterns by defining key research interests, journals, countries, new advancements, challenges, negative attitudes and future directions towards DTs in the AEC industry. However, this study is the first in its vital importance and uniqueness by providing a broad updated review of DTs in the AEC literature. Furthermore, this research laid a foundation for future researchers, policy makers and practitioners to explore the limitations in future research.
The adoption of green construction practices (GCP) has been on the increase in recent years as a means of reducing the negative effects of construction on the natural environment. However, GCP have been discovered to expose the construction workers to numerous health and safety (HS) risks, resulting from a decline in safety investment due to the economic burden associated with its adoption. This study explores the means through which GCP influence the HS performance of construction projects through economic performance. To obtain the views of contractors, a survey questionnaire was developed, and data was collected from project managers and site managers of "class A" contractors, with a response rate of 81.55%. The partial least squares structural equation modeling (PLS-SEM) technique was adopted to analyze the data. The results show that the effect of GCP on HS performance is fully mediated by economic performance. The study concludes that for projects that adopt GCP to have high levels of HS performance, they are required to have an optimal economic performance. Efforts should be intensified by the government in providing subsidies, tax waivers, and other incentives for adopters of GCP to ensure the economic performance of their projects since it guarantees high HS performance.