Process waste analysis for offsite production methods for house construction – A case study of factory wall panel production

There is a growing interest in the use of offsite manufacturing (OSM) in the construction industry disregarding criticisms of lacking real improvement from some offsite approaches adopted by housebuilders as compared to their onsite counterparts. Quantitative performance measures from previous studies are based on conventional onsite methods, with little attention paid to the performance and process improvements derived from various OSM methods. In response, a case study was conducted based on two OSM methods using standardized and non-standardized processes for the production stage of a factory-manufactured wall panel. Value system analysis and root cause analysis using the 5Whys method was adopted to evaluate possible improvements in terms of process waste. The study reveals that OSM production methods that replicate site arrangements and activities involving significant manual tasks do not necessarily provide a marked improvement from the conventional onsite method. Thus, there is a need to re-evaluate the processes involved to eliminate such embedded process wastes as non-value-added time and cost and to consider automating critical activities. The analysis adopted in the case study provides measurable evidence of the performance gained from having a structured workflow over a non-structured workflow. It also reveals how process wastes are generated in the production process of wall panels offsite

TOWARDS AN ONTOLOGY-BASED APPROACH TO MEASURING PRODUCTIVITY FOR OFFSITE MANUFACTURING METHOD

The steady decline of manual and skilled trades in the construction industry has increased the recognition of offsite manufacturing (OSM), an aspect of Design for Manufacture and Assembly (DFMA) methods as one way to boost productivity and performance. However, existing productivity estimation approaches are carried out in isolation thus limiting the sort of result obtained from such systems. Also, there is yet to be a holistic approach that enables productivity estimation using different metrics and integrates experts’ knowledge to predict productivity and guide decision making at the early development stage of a project. This study aims to develop a method that can be used to generate multiple estimations for all these metrics simultaneously through linking their relationships. An ontology-based knowledge modelling approach for estimating productivity at the production stage for OSM projects is proposed. A case study of panel system offsite is used as a proof-of-concept for data collection and knowledge modelling in an ontology. Results from the study through the use of rules and semantic reasoning retrieved cost estimates and time schedule for a panel system production with considerations for different design choices. It is thus proven that systemising the production process knowledge of OSM methods enables practitioners to make informed choices on product design to best suit productivity requirements. The developed method helps to reduce the level of uncertainty by encouraging measurable evidence and allows for better decision-making on productivity

A Semantic Offsite Construction Digital Twin- Offsite Manufacturing Production Workflow (OPW) Ontology

Offsite Manufacturing (OSM) is a modern and innovative method of construction with the potential to adopt advanced factory production system through a more structured workflow, standardised products, and the use of robotics for automation. However, there have been challenges in quantifying improvements from the conventional method, which leads to the low uptake. The concept of a digital twin (DT) is useful for OSM, which enables production to be represented virtually and visually including all activities associated with it, resources, and workflow involved. Thus, essential information in the product development process such as cost, time, waste, and environmental impacts can be assessed. However, the data required to have accurate results and better-informed decision-making come from heterogeneous data formats (i.e. spreadsheets and BIM models) and across different domains. The inclusion of semantic web technologies such as Linked Data (LD) and Web Ontology Language (OWL) models has proven to better address these challenges especially in terms of interoperability and unambiguous knowledge systematisation. Through an extensive systematic literature review followed up by a case study, an ontology knowledge structure representing the production workflow for OSM is developed. A real-life use case of a semi-automated production line of wall panel production is used to test and demonstrate the benefits of the semantic digital twin in obtaining cost and time data of the manufacturing for assessment. Results demonstrated the potential capability and power of capturing knowledge for an ontology to assess production workflow in terms of cost, time, carbon footprint thereby enabling more informed decision making for continuous improvements

The differing approaches to sustainability between practising and academic Quantity Surveyors

Most interpretations of sustainability in construction stem from the definition of sustainable development, which is a development that meets the needs of the present without compromising the future generation’s needs. Various research and sustainability studies within the construction industry focus on finding economical, social, and environmental balance. Construction professionals, such as Quantity Surveyors, begin their learning journey by studying in colleges and progressing to higher education. As the construction industry evolves through modern techniques, higher education institutions must also follow suit. These modern techniques have arisen due to the shift of ethos towards sustainability. Without the higher education institutions including this new knowledge in their curriculum, future professionals will not be equipped with the correct skills. Few research have been conducted in relation to students’ views on sustainability. Although such research is at a minute level, thus the converse side of the argument is how professional Quantity Surveyors view these topics on sustainability and whether they implement them in their daily duties. Hence, the research explores the differences in understanding between practicing and academic Quantity Surveyors on sustainable development in their various professional duties. The research was conducted using questionnaires that was distributed using survey monkey. The results were analysed through Spearman and ANOVA statistical tests to check their correlations. The study found a difference in the knowledge acquired by practicing and academic Quantity Surveyors. This finding conveys the importance of sustainability knowledge and how it is fundamental in achieving the UN sustainable goals and using such knowledge in practice

Success Factors in Mega Infrastructure Projects (MIPs): Developing Nations Perspectives

There is a common understanding that megaprojects are important drivers of societal change. Their impact is an important phenomenon because of the influence on both society and economy. Despite the best practices all around the globe, numerous challenges can move a megaproject from a programmed success to a failure scenario. It can create an uncertainty over the result, impact as well as over the justification of the enormous amount of resources spent. Despite much research done so far, it is still not clear what are the causes of megaproject success. However, there seems to be no clear understanding as to what are the major success factors on which a project is judged in developing nation. Hence, this study aims to analyse the most vital success factors that would label a megaproject as being a complete accomplishment. The research was conducted using quantitative survey. The questionnaires were distributed to different stakeholders who have participated in previous megaproject. The questions were based on a Likert's scale rating and analysed using relative important index (RII). The result from the analysis was then used in establishing the main success factors in mega project whilst focusing on what is regarded as the most important success factors as projects are unique with certain needs. The key finding from the study is the Project Managers experience and co existence with other stakeholders which was found as vital factor for the successful delivery of MIPs. Therefore, the research demonstrates the implication of the role of the project managers in terms of coordination of other parties in achieving stakeholders goal

Optimization of Aqueous Two-Phase Partitioning of Aureobasidium pullulans α-Amylase via Response Surface Methodology and Investigation of its Thermodynamic and Kinetic Properties

Industrial enzymes such as α-amylase must be thermostable and also easily purified/concentrated. Hence, aqueous two-phase partitioning systems (ATPS) was exploited for the partitioning of α-amylase from Aureobasidium pullulans due to its numerous advantages over conventional purification strategy. A. pullulans α-amylase was partially purified using ATPS via response surface methodology (RSM). The potentials of the ATPS-purified enzyme for possible industrial application such as resistance to thermal inactivation was investigated in comparison with the crude enzyme. PEG-6000 was the polymer of choice for ATPS as it resulted in higher purification factor (PF), %yield (Y), and partition coefficient (PC). At optimum levels (% w/v) of 20, 12 and 7.5 for PEG-6000, sodium citrate and sodium chloride respectively, maximum PF, Y and PC of 4.2, 88%, and 9.9 respectively were obtained. The response model validation and reliability were established based on the closeness between the experimented and predicted values. The kinetic and thermodynamic parameters such as Q10, t1/2, kd, D − value, Ed, of the ATPS-purified α-amylase indicated that it was thermostable at 50 to 60 °C compared to the crude α-amylase. A thermodynamically stable and ATPS-purified α-amylase from A. pullulans has properties easily applicable for most industrial processes

Radiation Shielding Properties of Synthetic Ca-Al2O3 Polymer Based Composites

Ionizing radiation exposure from medical diagnostic equipment, industries, nuclear research facilities, and nuclear weapon development has led to health impacts such as cancer and acute radiation syndrome, necessitating the use of proper radiation shielding. The optical and radiation shielding capabilities of Ca-Al2O3 polymer-based composites were explored in this article. The composites were made by combining synthesized Aluminum oxide (Al2O3) with calcium (Ca) formed from Periwinkle shells, Snail shells, and Seashells and calcining them at 1000 oC for 13 hours. The synthesized Ca-Al2O3 powders were dispersed into polymeric materials in a ratio of 1:1 using an effective melt-mixing process, then cast in a 10 cm by 10 cm square Mold with a thickness of 10 mm and allowed to set overnight at ambient temperature. The composite samples obtained were transferred to the Nigerian Nuclear Regulatory Agency (NNRA) in Ibadan for radiographic examinations and analyses. X-ray transmission through the manufactured composites samples was investigated using a well-collimated point source. The produced x-rays' initial intensity (Io) was determined. With the sample in front of the detector, the transmitted x-ray beam (I) was measured. The measurements were repeated three times for each composite sample, and the average value was calculated. Using relevant and referenced equations, the linear attenuation coefficient, half-value layer, relaxation length, and absorbance for each sample were calculated. The radiation shielding composites' x-ray photon absorptions were determined using transmission data by Beer's Lambert law. The XRF results revealed that the calcined samples were mostly calcium with only a few traces of other elements, with percentage calcium quantities of approximately 32, 37, and 34 for snail shells, seashells, and periwinkle shells, respectively, and the XRD result confirmed the Al2O3 polymorphs at approximately 32o and 57 o and the Aluminum phase at 46 o. For the three radiation shielding composites under investigation, the x-ray photon transmittance is quite low at 40 keV to 60 keV and comparatively high at 100 keV to 200 keV. From 100 keV to 200 keV, the transmittance of periwinkle shells and snail shell calcium sources polymer-based composites was similar, and their differences became significant at lower energies. For Ca-Al2O3 polymer-based composites with calcium contents sourced from seashells, periwinkle shells, and snail shells, the maximum linear attenuation coefficients were 1.0 cm-1, 0.79 cm-1, and 0.65 cm-1, respectively. At 60 keV and below, the radiation shielding composites have the highest attenuation coefficient. The half-value layer (HVL) of all the samples under investigation reduced abruptly at 40 and 60 keV and grew linearly as the energy increased from 100 to 200 keV. The relaxation length is comparatively low at 40 and 60 keV compared to other x-ray sources utilized at higher energies. Each radiation shielding composite's properties are determined by the amount of calcium present in the samples. Over a certain photon energy range (40 keV–200 keV), the Ca-Al2O3 polymer-based composites with calcium contents sourced from seashells were found to have higher x-ray attenuating characteristics than other composites. The attenuating capacity of all the composites under this study can be enhanced by increasing the radiation shielding composite thickness.     &nbsp

Electronic structure and surface properties of copper thiocyanate: a promising hole transport material for organic photovoltaic cells

Considering the significance of hexagonal copper thiocyanate (β-CuSCN) in several optoelectronic technologies and applications, it is essential to investigate its electronic structure and surface properties. Herein, we have employed density functional theory (DFT) calculations to characterise the band structure, density of states, and the energy-dependent X-ray photoelectron (XPS) valence band spectra at variable excitation energies of β-CuSCN. The surface properties in the absence and presence of dimethyl sulfoxide (DMSO), a solvent additive for improving perovskite solar cells’ power conversion efficiency, have also been systematically characterised. β-CuSCN is shown to be an indirect band gap material (Eg = 3.68 eV) with the valence band edge demonstrated to change from being dominated by Cu-3d at soft X-ray ionisation photon energies to Cu-3p at hard X-ray ionisation photon energies. The adsorption energy of dimethyl sulfoxide (DMSO) on the (100) and (110) β-CuSCN surfaces is calculated at −1.12 and −0.91 eV, respectively. The presence of DMSO on the surface is shown to have a stabilisation effect, lowering the surface energy and tuning the work function of the β-CuSCN surfaces, which is desirable for organic solar cells to achieve high power conversion efficiencies. View Full-Text Keywords: copper thiocyanate (CuSCN); hole transport layer (HTL); dimethyl sulfoxide (DMSO); electronic structure; XPS valence band spectra; work function; density functional theory (DFT

Towards a Hybrid Approach to BIM implementation – A Critical Discourse

BIM adoption in many countries involves different approaches including the use of government mandates. The UK’s 2016 BIM mandate for public projects to be delivered at BIM Level 2 maturity, is an example. However, BIM mandates do not apply to private sector projects which leave questions about the inclusivity of its adoption and the susceptibility of SMEs to being digitally disenfranchised. Developing countries yet to adopt BIM are at the risk of out-rightly imitating the mandate-driven policies of countries like the UK, without considering alternative options that might better suit their socio-economic realities. This research investigates the use of alternative strategies (nudge theory) for promoting BIM adoption for inclusivity of smaller organisations, the private sector or developing countries. By drawing on two interrelated yet independent theories of loss aversion theory and nudge theory, this study examines the current mandate-driven policies and provides a critical discourse around ways that these two theories can be combined to form a new kind of construct on the way BIM implementation is (or can be) understood. The result from the critical analysis suggests that a hybrid of mandate and nudge can be effective in promoting BIM and none of these approaches is self-sustaining given their challenges. This finding opens a new vista for applying behavioural policies based on nudge theory and its potentials for promoting BIM implementation in the construction sector

Demystifying the concept of offsite manufacturing method: Towards a robust definition and classification system

Purpose: Offsite manufacturing (OSM) is continuously getting recognised as a way to increase efficiency and boost productivity of the construction industry in many countries. However, the knowledge of OSM varies across different countries, construction practices and individual experts thus resulting into major misconceptions. The lack of consensus of what OSM is and what constitutes its methods creates a lot of misunderstanding across AEC industry professionals hence, inhibiting a global view and understanding for multicultural collaboration. Therefore, there is a need to revisit these issues with the aim of developing a deeper understanding of the concepts and to ascertain what is deemed inclusive or exclusive. Approach: A state-of-the-art review and analysis of literature on OSM was conducted to observe trends in OSM definitions and classifications. The paper identifies gaps in existing methods and proposes a future direction. Findings: Findings suggest that classifications are mostly aimed towards a particular purpose and existing classification system are not robust enough to cover all aspects. Therefore, there is need to extend these classification systems to be fit for various purposes. Originality: This paper contributes to the body of literature on offsite concepts, definition and classification, and provides knowledge on the broader context on the fundamentals of OSM