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Over the last few decades, the use of plastics as packaging materials has increased due to their properties and processibility. On the other hand, as a result of contact of packed food with plastics, traces of plastic components may migrate into the food medium contaminating it and affecting consumers’ health. This work concerns the study of migration of DINP and DOP plasticisers from PVC sheets into foodstuffs. PVC sheets using either type of plasticisers with different concentrations were prepared and then put in contact with different food simulants. Gravimetric analysis was used to determine the loss in plasticised PVC sheets upon immersion in food simulants. Changes in mechanical properties of tested sheets were observed. IR was used in the detection of plastic components in food simulants. A comparison was held between the migration of DINP and DOP plasticisers into food simulants.

The purpose of this study is to investigate heat transfer and electrokinetic non-Newtonian flow in a rectangular microchannel in the developed and transient states.

The Carreau–Yasuda model was considered to capture the non-Newtonian behavior of the fluid. The dimensionless forms of governing equations, including the continuity equation for the Carreau–Yasuda fluid, are numerically solved by considering the volumetric force term of electric current (DC).

The impact of pertinent parameters such as electrokinetic diameter (R), Brinkman number and Peclet number is examined graphically. It is observed that for increasing R, the bulk velocity decreases. The velocity of the bulk fluid reaches from the minimum to the maximum state across the microchannel over time. At the electrokinetic diameter of 400, the maximum velocity was obtained. Temperature graphs are plotted with changes in the various Brinkman number (0.1 < Br < 0.7) at different times, and local Nusselt are compared against changes in the Peclet number (0.1 < ℘e < 0.5). The results of this study show that by increasing the Brinkman number from 0.25 to 0.7, the temperature along the microchannel doubles. It was observed that increasing the Peclet number from 0.3 to 0.5 leads to 200% increment of the Nusselt number along the microchannel in some areas along the microchannel. The maximum temperature occurs at Brinkman number of 0.7 and the maximum value of the local Nusselt number is related to Peclet number 0.5. Over time in the transient mode, the Nusselt number also decreases along the microchannel. By the increasing of time, the temperature increases at given value of Brinkman, which is insignificant at Brinkman number of 0.1. The simulation results have been verified by Newtonian and non-Newtonian flows with adequate accuracy.

This study contributes to discovering the effects of transient flow of electroosmotic flow for non-Newtonian Carreau–Yasuda fluid and transient heat transfer through rectangular microchannel. To the authors’ knowledge, the said investigation is yet not available in existing literature.

Describes the novel utilization of waste newsprint paper as inexpensive agro‐fibers for production of lightweight building panels. Thermal gravimetric analysis of treated news paper fibers was studied as a method for testing fire retardancy of agro‐fibers in light building panels. The activation energy of degradation stages was evaluated by applying the Coats and Redfern method of analysis. Results showed that the treatment of newsprint waste with 6 per cent sodium silicate also improved fire retardancy in addition to improving the compressive strength of the produced panels, with the reduction in the bulk density to ∼28.6 per cent compared with gypsum panel. Such treatment gives the produced panels a relatively low water absorption property compared with those produced by other treatments.

Dissimilar materials found applications in the structural fields to withstand the different types of loads and provide multi-facet properties to the final structure. Aluminum alloy materials are mostly used in aerospace and marine industries to provide better strength and safeguard the material from severe environmental conditions. The purpose of this study is to develop new material with superior strength to challenge the severe environmental conditions.

In the present investigation, friction stir welding (FSW) dissimilar joints were prepared from AA6061 and AA5083 aluminum alloys, and the weld nugget (WN) was reinforced with hard reinforcement particles such as La₂O₃ and CeO₂. The tribological and mechanical properties of the prepared materials were tested to analyze the suitability of material in the aerospace and marine environmental conditions.

The results showed that the AA6061–AA5083/La₂O₃ material exhibited better mechanical and tribological characteristics. The FSW dissimilar AA6061–AA5083/La₂O₃ material exhibited lower wear rate of 7.37 × 10⁻³ mm3/m and minimum friction coefficient of 0.31 compared to all other materials owing to the reinforcing effect of La₂O₃ particles and the fine grains formed by FSW process at WN region. Further, FSW dissimilar AA6061–AA5083/La₂O₃ material displayed a maximum tensile strength and hardness of 378 MPa and 118 HV, respectively, among all the other materials tested.

This work is original and novel in the field of materials science engineering focusing on tribological characteristics of friction stir welded dissimilar aluminum alloys by the reinforcing effect of hard particles such as La₂O₃ and CeO₂.

The purpose of this paper is to address the thermo-physical impacts of unsteady magneto-hydrodynamic (MHD) boundary layer flow of non-Newtonian tangent hyperbolic nanofluid past a moving stretching wedge. To delineate the nanofluid, the boundary conditions for normal fluxes of the nanoparticle volume fraction are chosen to be vanish.

The local similarity transformation is implemented to reformulate the governing PDEs into coupled non-linear ODEs of higher order. Then, numerical solution is obtained for the simplified governing equations with the aid of finite difference technique.

Numerical calculations point out that pressure gradient parameter leads to improve all skin friction coefficient, rate of heat transfer and absolute value of rate of nanoparticle concentration. As well as, lager values of Weissenberg number tend to upgrade the skin friction coefficient, while power law index and velocity ratio parameter reduce the skin friction coefficient. Again, the horizontal velocity component enhances with upgrading power law index, unsteadiness parameter, velocity ratio parameter and Darcy number and it reduces with rising values of Weissenberg number.

A numerical treatment of unsteady MHD boundary layer flow of tangent hyperbolic nanofluid past a moving stretched wedge is obtained. The problem is original.

The purpose of this study is to provide a detailed descriptive account and analysis of corporate internet reporting (CIR) practices among non-financial companies listed on the Egyptian Exchange (EGX) at two points in time – December 2010 (pre) and December 2013 (peri) political and social unrest in Egypt.

The study developed a disclosure index to determine the extent of CIR practices among all non-financial companies listed on the EGX in December 2010 and December 2013. The study uses ordinary least squares (OLS) regressions and isometric log-ratio transformations for compositional independent variables to empirically examine the factors affecting CIR in Egypt using a modern institutional theory lens.

The findings of this investigation suggest that listed companies in Egypt have started embracing the power of the internet as a disclosure channel, but the extent of these practices increased significantly over the investigated period, with great variations evident among the sampled companies in this regard. Such variations were chiefly dependent on the changing institutional actors over the two time frames. Additionally, the findings show that the time factor is particularly important for a given institutional field to induce a sufficient diffusion of corporate practices, especially in periods with drastic institutional change.

The evidence presented reflects the voluntary nature of CIR practices and the absence of a reinforced regulatory framework for organizing and monitoring such practices, with companies having discretion in terms of the amount and type of information disclosed via their websites. The results should, therefore, provide useful guidelines for regulators and standard-setters in identifying best practices, which, in turn, should allow CIR practices to become more consistent, making them easier to monitor and govern.

To the best of the authors’ knowledge, this is the first study that examines CIR practices at two points in time using a comprehensive disclosure index and a modern institutional theory lens.

The purpose of this paper is to provide empirical evidence of the relationship between female representation on the board and forward-looking information disclosures (FLIDs).

The study uses the content analysis to analyze the narrative evidence from the annual financial reports of non-financial Jordanian companies listed on the Amman Stock Exchange. The final sample consists of 1,206 firm-year observations during the period 2008-2013.

The study provides evidence that gender diversity on boards positively affects the level of FLIDs. Further to this, the study reveals that family firms disclose more information than non-family firms.

Results of this study could be beneficial for a number of users of financial information such as, regulators, investors, auditors and lenders. The users might consider the findings of this study when they are using the company’s financial information. Consequently, users of this information could be better assisted to make right decisions.

This study contributes to the literature by identifying the role of gender on the level of FLID, particularly on family and non-family, a relatively little researched area.

The objective of the present work is to present the design optimization of composite cylindrical shell subjected to an axial compressive load and lateral pressure.

A novel optimization method is developed to predict the optimal fiber orientation in composite cylindrical shell. The optimization is carried out by coupling analytical and finite element (FE) results with a genetic algorithm (GA)-based optimization scheme developed in MATLAB. Linear eigenvalue were performed to evaluate the buckling behaviour of composite cylinders. In analytical part, besides the buckling analysis, Tsai-Wu failure criteria are employed to analyse the failure of the composite structure.

The optimal result obtained through this study is compared with traditionally used laminates with 0, 90, ±45 orientation. The results suggest that the application of this novel optimization algorithm leads to an increase of 94% in buckling strength.

The proposed optimal fiber orientation can provide a practical and efficient way for the designers to evaluate the buckling pressure of the composite shells in the design stage.

This study aims to examine the impacts of higher memory dependencies on a novel semiconductor material that exhibits generalized photo-piezo-thermo-elastic properties. Specifically, the research focuses on analyzing the behavior of the semiconductor under three distinct temperature models.

The study assumes a homogeneous and orthotropic piezo-semiconductor medium during photo-thermal excitation. The field equations have been devised to encompass higher order parameters, temporal delays and a specifically tailored kernel function to address the problem. The eigenmode technique is used to solve these equations and derive analytical expressions.

The research presents graphical representations of the physical field distribution across different temperatures, higher order plasma heat conduction models and time. The results reveal that the amplitude of the distribution profile is markedly affected by factors such as the memory effect, time, conductive temperature and spatial coordinates. These factors cannot be overlooked in the analysis and design of the semiconductor.

Specific cases are also discussed in detail, offering the potential to advance the creation of precise models and facilitate future simulations.

The research offers valuable information on the physical field distribution across various temperatures, allowing engineers and designers to optimize the design of semiconductor devices. Understanding the impact of memory effect, time, conductive temperature and spatial coordinates enables device performance and efficiency improvement.

This manuscript is the result of the joint efforts of the authors, who independently initiated and contributed equally to this study.

The aim of this study is to determine the prevalence of hypocalcaemia among first-trimester pregnant women and its contributing factors.

A cross-sectional study was carried out among first-trimester pregnant women who were recruited during their first antenatal visit. A total of 396 respondents of age 18-40 years completed the self-administered questionnaire (socio-demographic, socio-economic, obstetric information), validated semi-quantitative food frequency questionnaire for calcium (FFQ-calcium), anthropometric measurements (weight and height) and blood test for serum calcium during their first trimester.

The prevalence of hypocalcaemia based on serum calcium level of less than 2.11 mmol/L was 26.0 per cent (n = 103). The median serum calcium level was 2.2 mmol/L (IQR, 25th and 75th percentile – 2.1 and 2.3, respectively). Milk intake of less than two glasses per day during pregnancy showed a twofold increase in developing hypocalcaemia (OR, 2.231; 95 per cent CI, 1.399, 3.588). Other than that, underweight (aOR, 2.038; 95 per cent SK, 1.088, 3.820) and obese before pregnancy (aOR, 1.954; 95 per cent SK, 1.007, 3.790) are also predictors of hypocalcaemia.

The prevalence of hypocalcaemia among first-trimester pregnant women in this study was 26.0 per cent. Intake of two or more glasses of milk per day can help prevent hypocalcaemia at this stage of pregnancy.