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Despite a large amount of BIM data at the handover stage, it is still difficult to identify and effectively isolate valuable construction supply chain (CSC) data that need to be reliably handed over for operation. Moreover, the role of reconciling disparate data is usually played by one party. The integration of blockchain and BIM is a plausible framework for building a reliable digital asset lifecycle. This paper proposes a BIM single source of truth (BIMSSoT) data model using blockchain for ensuring a reliable CSC data delivery.

This paper utilises a blended methodology, the foundation of which is ingrained in business and management research with elements of information and communication technology (ICT) research wherever required. Knowledge elicitation case studies utilising novel interventions such as a data flow diagram (DFD), taxonomy and entity-relationship diagram (ERD) were used in this paper to develop the BIMSSoT data model. The model was validated using an expert forum, and its technological feasibility was established by developing a proof of concept.

The practical contribution of this research leads to the progression of BIM towards digital engineering to go beyond object-based 3D modelling by building structured and reliable datasets, transitioning from project-centric records to a digital ecosystem of linked databases by utilizing blockchain's potential for ensuring trusted data.

To the best of the author's knowledge, prior to this paper, no research had investigated a detailed data model development leveraging blockchain and BIM to integrate an immutable and complete record of CSC data as another dimension of BIM for operations.

To investigate the effect of cement and cement by‐pass dust (CBPD) as a stabilizer on the geotechnical properties of oil‐contaminated soils resulting from leaking underground storage tanks, or soils surrounding petroleum refineries and crude oil wells.

Oil‐contaminated soil (untreated soil) and a soil treated by bio‐remediation (treated soil) as well as a natural soil were obtained from Northern Oman. These soils were stabilized with cement and cement by‐pass dust at 0, 5, 10, 15 and 20 percent, by dry weight of the soil, and cured for seven, 14 and 28 days. Compaction, compressive strength, direct shear, permeability and leaching tests were carried out on the stabilized soils.

The results indicate that cement and cement by‐pass dust improve the properties of oil‐contaminated soils. Traces of arsenic, barium, cadmium, chromium and lead were found in the oil soils, but none of them exceeded the EPA limits.

Reuse in construction applications provides a safe and useful solution for the problem of the disposal of oil‐contaminated soils.

The paper addresses an environmental problem facing many oil companies in disposing of or treating contaminated soil. The approach presented in the paper offers a beneficial, safe and economical solution to this problem.

Cross-layer approach in media access control (MAC) layer will address interference and jamming problems. Hybrid distributed MAC can be used for simultaneous voice, data transmissions in wireless sensor network (WSN) and Internet of Things (IoT) applications. Choosing the correct objective function in Nash equilibrium for game theory will address fairness index and resource allocation to the nodes. Game theory optimization for distributed may increase the network performance. The purpose of this study is to survey the various operations that can be carried out using distributive and adaptive MAC protocol. Hill climbing distributed MAC does not need a central coordination system and location-based transmission with neighbor awareness reduces transmission power.

Distributed MAC in wireless networks is used to address the challenges like network lifetime, reduced energy consumption and for improving delay performance. In this paper, a survey is made on various cooperative communications in MAC protocols, optimization techniques used to improve MAC performance in various applications and mathematical approaches involved in game theory optimization for MAC protocol.

Spatial reuse of channel improved by 3%–29%, and multichannel improves throughput by 8% using distributed MAC protocol. Nash equilibrium is found to perform well, which focuses on energy utility in the network by individual players. Fuzzy logic improves channel selection by 17% and secondary users’ involvement by 8%. Cross-layer approach in MAC layer will address interference and jamming problems. Hybrid distributed MAC can be used for simultaneous voice, data transmissions in WSN and IoT applications. Cross-layer and cooperative communication give energy savings of 27% and reduces hop distance by 4.7%. Choosing the correct objective function in Nash equilibrium for game theory will address fairness index and resource allocation to the nodes.

Other optimization techniques can be applied for WSN to analyze the performance.

Game theory optimization for distributed may increase the network performance. Optimal cuckoo search improves throughput by 90% and reduces delay by 91%. Stochastic approaches detect 80% attacks even in 90% malicious nodes.

Channel allocations in centralized or static manner must be based on traffic demands whether dynamic traffic or fluctuated traffic. Usage of multimedia devices also increased which in turn increased the demand for high throughput. Cochannel interference keep on changing or mitigations occur which can be handled by proper resource allocations. Network survival is by efficient usage of valid patis in the network by avoiding transmission failures and time slots’ effective usage.

Literature survey is carried out to find the methods which give better performance.

This study aims to investigate the association between vitamin D measured in serum 25 hydroxyvitamin D [25(OH)D] and outcomes of COVID-19 patients in Bahrain. This paper hypothesized that lower serum 25(OH)D concentration in COVID 19 patients is associated with longer viral clearance time (VCT) and higher risk of admission to the intensive care unit (ICU).

This study used a retrospective cohort design of patients admitted to Salmaniya Medical Complex, Manama, Kingdom of Bahrain, from February to June 2020. This study included patients with positive, confirmed COVID-19 diagnosis made using reverse transcription-polymerase chain reaction (RT-PCR), World Health Organization diagnosis manual and local diagnostic guidelines. Primary outcome measures were: VCT measured as the time in days between the first positive RT-PCR test result and the first of two consecutive negative RT-PCR results on recovery and admission need to ICU.

A total of 450 patients were analyzed; mean age was 46.4 ± 12.4 years and 349 (78%) were men. Mean 25(OH)D concentration was 41.7 ± 23.7 nmol/L for the entire sample. Severe vitamin D deficiency (<25 nmol/L) was present in 20%, mild-to-moderate deficiency (25–50 nmol/L) in 55%, insufficiency (50 to <75 nmol/L) in 18% and sufficiency (=75 nmol/L) in 7%. The mean VCT was 12.9 ± 8.2 days. Multivariate linear regression analysis showed that severe vitamin D deficiency was associated with longer VCT, with an average of three extra days after correction for age and sex (β = 3.1; p = 0.001). Multinomial regression analysis showed that vitamin D deficiency was associated with an 83% increased risk of admission to ICU after correction for age and sex (odds ratio = 1.8; p = 0.03).

The results showed that severe vitamin D deficiency was associated with longer recovery time from COVID-19. Low serum 25(OH)D is associated with increased need for critical care in an ICU. Large-scale randomized controlled trials are necessary to further investigate the complex association between vitamin D and COVID-19 infection.