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Internal hydrophobation by adding hydrophobic agents during the mixing process is a method for reducing water permeability of cement based materials. It can be used as an alternative to other methods such as reducing water cement ratio (w/c) or using silica fume (SF). However, it may affect other properties of cement based materials such as compressive strength. In this paper the results of an experimental study on compressive strength of different hcps with main variables w/c, SF and hydrophobic agents are presented. Rapeseed oil and alkyl alkoxysilane were selected as hydrophobic agents. Although, a low dosage of hydrophobic agents can be more effective than lowering w/c or adding SF in reducing water permeability, an obvious reduction was observed in compressive strength by this way of internal hydrophobation compared to the other above mentioned methods. Different reasons such as lower hydration degree, chemical reactions of hydrophobic agents and non-uniform distribution of hydrophobic materials in the hcp could have resulted in lower compressive strength of hydrophobed samples. Using other types of hydrophobic agents or impregnation after the curing process can be other alternatives which would have less effect on compressive strength.

Information security is a critical issue in all organizations. The success of information security in libraries depends, to a large extent, on the effective behavior of administrators, librarians, users and all human staff. Accordingly, this study aims to design a model for identifying human factors affecting information security in libraries.

This study is applied in terms of research objectives and is a survey in terms of data collection. Moreover, it goes under the rubric of structural equation modeling in terms of the relationship between variables. The statistical population consisted of 100 managers and librarians of academic and public libraries of Hamadan in Iran. A questionnaire was used for data collection. The face and content validity of the questionnaire were examined using the expert’s opinions in the field of Iranian libraries. Also, the reliability of the questionnaire was calculated through Cronbach’s alpha coefficient. Data were analyzed using SPSS 16 and Smart PLS 2.

The results showed that among the components of information security, the highest score was designated to self-esteem (4.11 ± 0.57) and level of skill (4.07 ± 0.59), whereas the lowest score belonged to the level of education (3.51 ± 0.74). Ranking human factors affecting information security showed that experience with Rank 1 had the most impact, whereas the level of skill with Rank 6 had the least impact on information security.

In this study, for the first time, a model was designed and tested for human factors affecting information security in libraries. Information security professionals, librarians and library and information science researchers can exploit this model in the future.

To amend the efficiency of engineering processes and electronic devices, it is very urgent to assess the irreversibility in the term entropy generation (EG). The efficiency of energy transportation in a system can be improved by minimization of the rate of EG. In this context, the aim of the present study is to estimate irreversible losses of an unsteady magnetohydrodynamic (MHD) flow of a viscous incompressible electrically conducting non-Newtonian molybdenum disulfide-polyethylene glycol Casson nanofluid past a moving vertical plate with slip condition under the influence of Hall current, thermal radiation, internal heat generation/absorption and first-order chemical reaction. Molybdenum disulfide (MoS₂) nanoparticles are dispersed in the base fluid polyethylene glycol (PEG) to make Casson nanofluid. Casson fluid model is considered to characterize the rheology of the non-Newtonian fluid, whereas Rosseland approximation is adopted to simulate the thermal radiative heat flux in the energy equation.

The closed-form solutions are obtained for the model equations by using the Laplace transform method (LTM). Graphs and tables are prepared to examine the impact of pertinent flow parameters on the pertinent flow characteristics. The energy efficiency of the system via the Bejan number is studied extensively.

Analysis reveals that Hall current has diminishing behavior on entropy production of the thermal system. Strengthening of the magnetic field declines the velocity components and prop-ups the rate of EG. Adding nanoparticles into the base fluid reduces the EG, whereas there are an optimum volume fraction of nanoparticles for which the EG is minimized. Further, the rate of decay of EG is prominent in molybdenum disulfide-polyethylene glycol in comparison to PEG.

The results of this study would benefit the industrial sector in achieving the maximum heat transfer at the cost of minimum irreversibilities with an optimal choice of embedded thermophysical parameters. In view of this agenda, this study would be adjuvant in powder technology, polymer dynamics, metallurgical process, manufacturing dynamics of nano-polymers, petroleum industries, chemical industries, magnetic field control of material processing, synthesis of smart polymers, etc.

The novelty of this study is to encompass the analytical solution by using the LTM. Such an exact solution of non-Newtonian fluid flow is rare in the literature. Limited research articles are available in the field of EG analysis during the flow of non-Newtonian nanoliquid subject to a strong magnetic field.

In order to include the non-negligible lag relaxation time feature that is characteristic of heat transfer in biological bodies, the classical Fourier's law of heat conduction has to be generalized as the Maxwell–Cattaneo law resulting in the thermal-wave model of bio-heat transfer. The purpose of the paper is to retrieve the unknown time-dependent blood perfusion coefficient in such a thermal-wave model of bio-heat transfer from (non-intrusive) measurements of the temperature on an accessible sub-portion of the boundary that may be taken with an infrared scanner.

The nonlinear and ill-posed problem is reformulated as a nonlinear minimization problem of a Tikhonov regularization functional subject to lower and upper simple bounds on the unknown coefficient. For the numerical discretization, an unconditionally stable direct solver based on the Crank–Nicolson finite-difference scheme is developed. The Tikhonov regularization functional is minimized iteratively by the built-in routine lsqnonlin from the MATLAB optimization toolbox. Numerical results for a benchmark test example are presented and thoroughly discussed, shedding light on the performance and effectiveness of the proposed methodology.

The inverse problem of obtaining the time-dependent blood perfusion coefficient and the temperature in the thermal-wave model of bio-heat transfer from extra boundary temperature measurement has been solved. In particular, the uniqueness of the solution to this inverse problem has been established. Furthermore, our proposed computational method demonstrated successful attainment of the perfusion coefficient and temperature, even when dealing with noisy data.

The originalities of the present paper are to account for such a more representative thermal-wave model of heat transfer in biological bodies and to investigate the possibility of determining its time-dependent blood perfusion coefficient from non-intrusive boundary temperature measurements.

When modeling heat propagation in biological bodies, a non-negligible relaxation time (typically between 15-30 s) is required for the thermal waves to accumulate and transfer, i.e. thermal waves propagate at a finite velocity. To accommodate for this feature that is characteristic to heat transfer in biological bodies, the classical Fourier's law has to be modified resulting in the thermal-wave model of bio-heat transfer. The purpose of the paper is to retrieve the space-dependent blood perfusion coefficient in such a thermal-wave model of bio-heat transfer from final time temperature measurements.

The non-linear and ill-posed blood perfusion coefficient identification problem is reformulated as a non-linear minimization problem of a Tikhonov regularization functional subject to lower and upper simple bounds on the unknown coefficient. For the numerical discretization, an unconditionally stable direct solver based on the Crank–Nicolson finite difference scheme is developed. The Tikhonov regularization functional is minimized iteratively by the built-in routine lsqnonlin from the MATLAB optimization toolbox. Both exact and numerically simulated noisy input data are inverted.

The reconstruction of the unknown blood perfusion coefficient for three benchmark numerical examples is illustrated and discussed to verify the proposed numerical procedure. Moreover, the proposed algorithm is tested on a physical example which consists of identifying the blood perfusion rate of a biological tissue subjected to an external source of laser irradiation. The numerical results demonstrate that accurate and stable solutions are obtained.

Although previous studies estimated the important thermo-physical blood perfusion coefficient, they neglected the wave-like nature of heat conduction present in biological tissues that are captured by the more accurate thermal-wave model of bio-heat transfer. The originalities of the present paper are to account for such a more accurate thermal-wave bio-heat model and to investigate the possibility of determining its space-dependent blood perfusion coefficient from temperature measurements at the final time.

Although organizational citizenship behaviour (OCB) is a concept associated with significant values within the modern workplace, many employees find it challenging to exhibit some necessary extra-role behaviours, such as helping co-workers complete their duties when a situation demands it. Currently, in the South African workspace, fostering OCB among employees is a concern to people practitioners. Specifically, extra-role types of behaviour are declining among professionals as 21st-century technologies promote remote-working policy, leaving employees to work robotically with computers and having no colleagues around to seek or render assistance with their duties. Moreover, professionals are overwhelmed with the timely and endless obligations received frequently and hardly have time and energy for extra-role behaviours. In addition, physical and psychological health-related concerns such as technology stress and career worries are among the contemporary issues affecting human resource (HR) management in this present time. This necessitates more scholarly actions in the niche of OCB, especially identifying and arresting its hindrances. However, a thorough review of the literature on OCB revealed a paucity of scientific reports in the areas of relationships between technostress, career concerns and OCB. Hence, the proposed chapter seeks to bridge the gap in the literature of OCB by theoretically exploring the relationships between technostress, career concerns and OCB in the professional services context in South Africa.

In this study, polyvinyl alcohol (PVA)/poly[acrylic acid (AAc)-co-acrylamide (AM)] composite hydrogel was prepared by radical copolymerization in the presence of Fe³⁺ freezing-thawing method. The swelling behavior of the hydrogel was investigated. The novel synthesized hydrogel was used as an adsorbent for the removal of dyes from aqueous solutions. In this paper, methylene blue and maxilon blue 5G were selected as representative cationic dyes. In addition, adsorption isotherm models were used to describe the dye adsorption process.

The prepared composite hydrogel was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, field emission scanning electron microscopy and UV–visible.

The prepared hydrogel exhibited excellent adsorption ability for both dyes. Various experimental conditions affecting the dye adsorption were explored to achieve maximum removal of both dyes. In addition, adsorption isotherm models were used to describe the dye adsorption process.

To the best of the author’s knowledge, synthesis of PVA/poly(AAc-co-AM) composite hydrogel in the presence of Fe³⁺ and investigation of the removal of methylene blue and maxilon blue 5G dyes is done for the first time successfully.

A significant number of studies have been conducted to analyze and understand the relationship between gas emissions and global temperature using conventional statistical approaches. However, these techniques follow assumptions of probabilistic modeling, where results can be associated with large errors. Furthermore, such traditional techniques cannot be applied to imprecise data. The purpose of this paper is to avoid strict assumptions when studying the complex relationships between variables by using the three innovative, up-to-date, statistical modeling tools: adaptive neuro-fuzzy inference systems (ANFIS), artificial neural networks (ANNs) and fuzzy time series models.

These three approaches enabled us to effectively represent the relationship between global carbon dioxide (CO₂) emissions from the energy sector (oil, gas and coal) and the average global temperature increase. Temperature was used in this study (1900-2012). Investigations were conducted into the predictive power and performance of different fuzzy techniques against conventional methods and among the fuzzy techniques themselves.

A performance comparison of the ANFIS model against conventional techniques showed that the root means square error (RMSE) of ANFIS and conventional techniques were found to be 0.1157 and 0.1915, respectively. On the other hand, the correlation coefficients of ANN and the conventional technique were computed to be 0.93 and 0.69, respectively. Furthermore, the fuzzy-based time series analysis of CO₂ emissions and average global temperature using three fuzzy time series modeling techniques (Singh, Abbasov–Mamedova and NFTS) showed that the RMSE of fuzzy and conventional time series models were 110.51 and 1237.10, respectively.

The paper provides more awareness about fuzzy techniques application in CO₂ emissions studies.

These techniques can be extended to other models to assess the impact of CO₂ emission from other sectors.

The purpose of this study is to investigate the effect of panel connections on the hygrothermal performance of facade panels using a coupled, transient heat and moisture transfer analysis.

A coupled, transient heat and moisture transfer analysis has been conducted to investigate the effect of panel connections in the hygrothermal behavior of facade panels. Governing partial differential equations for the coupled heat and moisture transfer were formulated. Four panel connections proposed by pre-cast/pre-stressed concrete institute were modeled for the ultra-high performance fiber-reinforced concrete facade panel as illustrations and a finite element method was used to solve the numerical models.

The results of heat transfer analysis showed that steel connections could significantly reduce the thermal resistivity of facade panels by converging heat fluxes and acting as thermal bridges within facade panels. The results also showed that the maximum heat flux in the steel connector of the panel to foundation connection was 10 times higher compared to the other connections. Also, the results of moisture transfer showed that air gaps between the panels had higher moisture flux compared to the other layers in the models. The results show the significant importance of panel connections in the energy performance analysis of facade systems. They also highlight the importance of devising novel connection designs and materials that consider the transient, coupled heat and moisture transfer in the connections to effectively exploit the potential opportunities provided by innovative facade systems to improve building energy efficiency.

This paper, for the first time, investigates the effect of panel connections in the hygrothermal performance of building facade systems using a coupled, transient heat and moisture transfer analysis.

This study explores the feasibility of substituting freshwater with alternative water sources such as potable water (PW), harvested rainwater (HRW), stormwater (SW), borewell water (BW) and seawater (Sea W) in concrete manufacturing. The aim is to evaluate the potential of these alternative sources to support sustainable development, reduce environmental impact and conserve freshwater resources in the construction industry.

The research followed established concrete production standards and evaluated the chemical properties of various water sources. Fresh concrete characteristics, including setting time, workability and mechanical properties (compressive, split tensile and flexural strength), were tested at 7, 28 and 90 days. Durability assessments utilized the Volhard assay for chloride content, RCPT for chloride permeability and a physical sulfate attack test. Additionally, a life cycle assessment (LCA) examined the environmental impacts, while an economic analysis assessed cost implications for each water source.

The results showed only minor differences of 2%–3% in the fresh and mechanical properties of concrete using alternative water sources, with no significant changes in compressive, tensile or flexural strength compared to potable water. The Rapid Chloride Penetration Test (RCPT) and Nord Test techniques showed that all water sources, except seawater, are suitable for concrete mixing, as they enhance concrete durability due to their very low chloride ion concentrations, which minimize the risk of steel corrosion. The sulfate attack, including mass loss and expansion measurements for various water sources, indicates low susceptibility to except seawater. SEM and EDS HRW and SW also showed denser microstructures compared to Potable Water, indicating the absence of voids or cracks and the formation of ettringite needles, while seawater posed challenges due to high chloride content and corrosion risks. The LCA indicated that SW had the lowest environmental impact, while seawater posed substantial challenges. The economic analysis confirmed SW as the most cost-effective option, with all sources meeting production standards except seawater.

This study provides new insights into the sustainable use of non-potable water sources in concrete manufacturing. It demonstrates the viability of using HRW, SW and BW as alternative water sources to potable water, supporting sustainability goals in construction while conserving vital freshwater resources and reducing environmental impact.