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Poly(ethylene terephthalate) (PET) waste from soft drink bottles was incorporated into palm olein alkyd to produce new polyol for use in polyurethane resins as surface protection on metal surfaces.

Alkyd was prepared from palm olein, glycerol and phthalic anhydride. PET underwent simultaneous glycolysis and transesterification reactions with the alkyd. Varying the amount of PET has led to polyols with different viscosities. Polyurethane resins were produced by reacting the polyols with toluene diisocyanate. The resins were coated on mild steel panels and cured. Performances of the cured films were tested.

The polyurethanes (PU) resin cured to a harder film with better thermal stability. Films showed excellent adhesion properties, while higher content of PET exhibited higher pencil hardness, better water, salt, acid and alkali resistance.

Other vegetable oils could also be used. The alkyd structure could be changed by formulation to have different functionality and the ability to incorporate higher amount of PET waste. Rate of glycolysis of PET could be increased by higher amount of ethylene glycol.

This method has managed to use waste PET in producing new polyol and PU resins. The cured films exhibit good mechanical and chemical properties, as well as excellent adhesion and thermal stability.

The non-biodegradable PET has created environmental pollution problems connected to littering and illegal landfilling. It has become necessary to pay greater attention to recycling PET bottles for obtaining valuable products.

This approach is different from the earlier reports, where PET was recycled to recover the raw materials.

Motivated by recent rapid exchange rate depreciations, shrank economic growth, high inflation, and persistent trade deficits, this study examines the trade balance (TB) in the face of the recent dynamics of the stated macroeconomic factors, which are also important determinants of the TB. The symmetric test of the J-curve phenomenon for the selected Sub-Saharan African (SSA) countries is revisited in this regard. The study uses panel data from 1970 to 2020 for ten of these countries for the longitudinal panel analysis with the TB as the dependent variable and the real exchange rate, foreign and domestic national incomes, and trade openness as the set of independent variables.

Because the underlying data set involves a heterogeneous panel of relatively short N and long T, the pooled mean group (PMG) and mean group (MG) heterogeneous panel models are employed based on the Hausman test for parameter consistency in heterogeneous panels.

The findings largely support the domestic income growth– TB worsening and the foreign income growth– TB improvement hypotheses. Trade openness is found to mostly augment the TB performance of the countries. The results also validated the J-curve effect for only 3/10 and 2/10 countries in the PMG and MG models, respectively. The divergence for most of the countries is attributed to possible import compression and institutional structure of SSA countries.

Given the favorable effects of trade openness on the TB performance of SSA countries, it is recommended that SSA countries place much emphasis on import-substitution industrialization and value addition to their natural resources as well as investment-driven growth policies to improve the competitiveness of their exports and reverse the chronic deficits in their TBs.

This paper is unique for invoking heterogeneous panel models to analyze the TB in light of recent dynamics of its determinants, as well as providing an update on the symmetric test of the J-curve phenomenon for the selected SSA countries.

In developing countries, adoption of building information modelling (BIM) concept within the architecture, engineering and construction (AEC) curricula in universities is a relatively new effort, and subsequently, studies on the status of BIM implementation in universities are rare. This study, therefore, becomes imperative with a view to identifying and examining the barriers to the incorporation of BIM into quantity surveying (QS) undergraduate curriculum in Nigerian universities.

The study adopted a questionnaire survey, which was targeted at the academia and students from two selected universities offering QS honours degree programme. Data collected were analysed using mean score, Mann–Whitney test and factor analysis.

The study identified 30 barriers, and the analysis of the ranking revealed that 17 (out of 30) identified barriers were considered as the most serious barriers. The study, through factor analysis, grouped the 30 identified barriers into six major factors.

The findings provide greater insights and empirical evidence on the major barriers to implementation of BIM education in developing countries.

The identified barriers are relevant not only to QS education but also to other related disciplines within the AEC context. These findings would be of great value to academic staff and university management board to develop strategies for incorporating BIM into AEC disciplines curricula in developing countries at large.

Extensive research towards identifying the attributable cost overrun factors globally has been conducted predominantly from a survey-oriented perspective, which disregard the contextual basis on which these triggers manifest. This study aims to explore the driving factors of cost overrun in highway projects, specific to the Nigerian context.

The research used a context-based approach to seek project stakeholders’ perspectives on the key drivers of cost overrun in highway projects in Nigerian. Semi-structured interviews were conducted with client, contractor and consultant organisations involved in the provision of highway infrastructure projects in Nigeria. The collected data was analysed using a developed coding framework grounded on a case study approach, principles of inductive thematic analysis and saliency analysis to identify the key drivers.

Findings from the analysis identified triggers from macroeconomic, societal, leadership and project management perspectives with synergistic relationships with each other based on prevalence and significance. Among the key triggers is a delay in work progress, political instability, adverse weather, social issues, delay in progress payment to contractors and modification of project scope. In conclusion, the triggers of cost overrun in highway projects are contextually driven by the complex nature of the project management, societal, macroeconomic and leadership triggers specific to the Nigerian context.

The research was limited to only highway infrastructure projects in Nigeria. Furthermore, the findings are based on a small sample size, and thus, caution must be taken before applying the outcome of this study in a generalised way to other contexts.

Practically, the stakeholders i.e. client, contractors and consultants should acknowledge the contextual circumstances in which each of the triggers takes place, which will aid in developing pragmatic measures and make the right decisions towards addressing these triggers during any highway construction project in Nigeria and enhance the chances of project success.

The context-based approach applied in this study is expected to provide a new insight in understanding the triggers of cost overruns, especially in highway projects in Nigeria and indeed other developing countries with similar governance characteristics

This study aims to explore the stagnation flow over a shrinking surface in a hybrid nanofluid consists of Al₂O₃ and Cu nanoparticles. Here, the flow is subjected to the magnetohydrodynamic (MHD) and the melting phenomenon effects.

The similarity variables are used to gain the similarity equations. These equations are solved via the bvp4c solver. The effects of several physical parameters on the flow and the thermal characteristics of the hybrid nanofluid are analysed and discussed. Later, the temporal stability analysis is used to determine the stability of the dual solutions obtained as time evolves.

Results show that two solutions are found for the limited range of the stretching/shrinking parameter λ, and then these solutions are terminated at λ=λc. The rise of the melting parameter Me from 0 to 2 contributes to enhance 109.63% of the local Nusselt number Rex-1/2Nux and 3.30% of the skin friction coefficient Rex1/2Cf. Contrarily, the values of Rex-1/2Nux and Rex1/2Cf decline by 25.04% and 5.58%, respectively, as the magnetic parameter Mg increases from 0 to 0.3. Additionally, Al₂O₃-Cu/water has the highest values of Rex1/2Cf and the lowest values of Rex-1/2Nux. Lastly, it is found that the first solution is physically stable as time evolves.

This paper considers the MHD stagnation point flow of a hybrid nanofluid over a shrinking surface with the melting phenomenon effects. Most importantly, it is shown that there exist dual solutions within a specific range of the physical parameters. Besides, the temporal stability of the solutions is also reported in this study. The finding can contribute to foresee the flow and thermal behaviours in industrial applications. Also, the suitable values of parameters can be determined to avoid misjudgement in flow and heat transfer analysis.

This paper aims to analyse numerically the unsteady stagnation-point flow of Cu-Al₂O₃/H₂O hybrid nanofluid towards a radially shrinking Riga surface with thermal radiation.

The governing partial differential equations are transformed into a set of ordinary (similar) differential equations by applying appropriate transformations. The numerical computation of these equations including the stability analysis is conducted using the bvp4c solver.

Two solutions are possible within the allocated interval: shrinking parameter, unsteadiness decelerating parameter, electro-magneto-hydrodynamics (EMHD) parameter, nanoparticles volumetric concentration, radiation parameter and width parameter, whereas the stability analysis certifies that the first (upper branch) solution, which fulfills the boundary conditions is the physical/real solution. The EMHD parameter generated from the application of Riga plate enhances the skin friction coefficient as well as the heat transfer process. The width parameter d is also one of the factors in the deterioration of the skin friction coefficient and heat transfer rate. It is crucial to control the width parameter of the magnets and electrodes to obtain the desired outcome. The radiation parameter is not affecting the boundary layer separation because the critical values are unchanged. However, the addition of radiation and unsteadiness decelerating parameters boosts the thermal rate.

The results are novel and contribute to the discovery of the flow and thermal performance of the hybrid nanofluid subjected to a radially shrinking Riga plate. Besides, this work is beneficial to the other researchers and general audience from industries regarding the factors which contribute to the thermal enhancement of the working fluid.

The purpose of this paper is to identify and assess the perceptions of constructional professionals on barriers to implementation of building information modeling (BIM) within the Nigerian construction industry.

A scoping literature review was conducted to identify the fourteen barriers to implementation of BIM, which were employed to design a questionnaire survey. Data collected were analyzed using descriptive statistics, mean score, Kruskal–Wallis test, analysis of variance and multivariate techniques such as factor analysis.

The descriptive and empirical analysis demonstrated a disparity of ranking of the 14 barriers factors among the groups; however no statistically significant differences among the 14 barriers to BIM. Based on the mean score ranking results, only three (out of 14) barriers are identified as critical (mean score greater than 3.5): few studies available on BIM and lack of knowledge, inexistence or inadequate government policies, and high cost of implementation. The results of the one-sample t-tests show that they were statistically significant differences in 10 out of 14 barriers as follows: few studies available on BIM and lack of knowledge, lack of demand for use and acceptance of BIM, inadequate contractual coordination, lack of specified standards, cost of data and information sharing, technological availability issues, reluctance of other stakeholders, business and cultural changes, data and intellectual property issues, and interoperability issues. The study, through factor analysis, categorized the fourteen barriers to BIM implementation into four principal factors. The factors are: technology and business-related barriers; training and people-related barriers; cost and standards-related barriers; and process and economic-related barriers.

The identification and assessment of the key barriers to BIM implementation would be useful for the construction professionals and other stakeholder of the construction industry with the view to advance BIM adoption in Nigeria. This could also be extended to other developing countries through considerations of the local economic conditions, given the status of BIM as being in the germinating stage of development in Africa.

The study provides insights on the barriers to BIM implementation across the Nigerian construction sector environments. The innovative aspect of the study is the identification of the ordered and grouped (composite) set of barriers to BIM which could be used to developing appropriate mitigating solutions.

The purpose of this study is to examine the moderating influence of the external environment on the relationship between entrepreneurial competencies, entrepreneurial orientation, entrepreneurial network, government business support and SMEs performance. The objectives of the study are achieved using the resource-based view and dynamic capability theory.

The survey method of research was used by personally administering questionnaires to the respondents. Multistage sampling techniques are used in selecting 470 SMEs owners/managers that participated in the survey. SPSS 24 and PLS-SEM 3.0 were used in the analysis of the data.

In the Nigerian context, the findings indicated that EC, EO and GBS directly influence the SMEs performance. Surprisingly, SMEs performance is not influenced by EN. Similarly, EE significantly moderated the relationship between EC, GBS and SMEs performance. On the contrary, EE does not have any moderating influence on the relationship between EO, EN and SMEs performance.

The study is limited to northeastern Nigeria. The study is limited to the EC, EO, EN GBS EE and SMEs performance and the use of cross-sectional data. The findings imply that SMEs owners/managers need a high level of entrepreneurial competencies and government business support to achieve a better performance especially in an external environment that is characterised by dynamism, diversity, complexity and hostility. Hence, providing support for both RBV and DCT.

Thus, the study offers additional empirical evidence from Nigeria and also expands knowledge and understanding in this field. The findings offer owners/managers, government agencies, financial institutions and other stakeholders of SMEs strategies EC, EO, GBS and EE to achieve a better SMEs performance.

The conceptual framework of the study is unique, and the study was conducted in northeastern Nigeria which is grossly underrepresented in the literature. It also provided understanding on the moderating influence of EE on the framework.

The purpose of this paper is to numerically analyze the stagnation point flow of Cu-Al2O3/water hybrid nanofluid with mixed convection past a flat plate and circular cylinder.

The similarity equations that reduced from the boundary layer and energy equations are solved using the bvp4c solver. The duality of solutions is observed within the specific range of the control parameters, namely, mixed convection parameter λ, curvature parameter γ and nanoparticles volumetric concentration ϕ1 for alumina, while for copper ϕ2. The stability analysis is also designed to justify the particular solutions’ stability. Additionally, the idea to obtain the solution for large value of λ and γ is also presented in this paper.

Two solutions exist in opposing and assisting flows up to a critical value λc where λc lies in the opposing region. An upsurge of the curvature parameter tends to extend the critical value (delay the separation process), whilst increase the heat transfer performance of the working fluid. Meanwhile, the application of hybrid Cu-Al2O3/water nanofluid also can decelerate the separation of laminar boundary layer flow and produce higher heat transfer rate than the Cu–water nanofluid and pure water.

The results are new and original. This study benefits to the other researchers, specifically in the observation of the fluid flow characteristics and heat transfer rate of the hybrid nanofluid. Also, this paper features with the mathematical formulation for the solution with large values of λ and γ.

The purpose of this paper is to present a detailed and critical look at the evolution of online survey research since Evans and Mathur’s (2005) article on the value of online surveys. At that time, online survey research was in its early stages. Also covered are the present and future states of online research. Many conclusions and recommendations are presented.

The look back focuses on online surveys, strengths and weaknesses of online surveys, the literature on several aspects of online surveys and online survey best practices. The look ahead focuses on emerging survey technologies and methodologies, and new non-survey technologies and methodologies. Conclusions and recommendations are provided.

Online survey research is used more frequently and better accepted by researchers than in 2005. Yet, survey techniques are still regularly transformed by new technologies. Non-survey digital research is also more prominent than in 2005 and can better track actual behavior than surveys can. Hybrid surveys will be widespread in the future.

The paper aims to provide insights for researchers with different levels of online survey experience. And both academics and practitioners should gain insights.

Adhering to a strong ethics code is vital to gain respondents’ trust and to produce valid results.

Conclusions and recommendations are offered in these specific areas: defining concepts, understanding the future role of surveys, developing and implementing surveys and a survey code of ethics. The literature review cites more than 200 sources.