R.C. Mehta, M.J. Pandya and T. Jayachandran
Under‐ and over‐expanded jet flows are calculated for theEuler equations. The solution procedure is based on the two‐stageRunge‐Kutta time‐stepping scheme. The studies of the flow…
Abstract
Under‐ and over‐expanded jet flows are calculated for the Euler equations. The solution procedure is based on the two‐stage Runge‐Kutta time‐stepping scheme. The studies of the flow field structure in diffusers, free jets and impinging jets have been investigated for a range of jet‐to‐stream total pressure ratios and for different exit Mach numbers. The resulting flows show a complex shock‐shear expansion structure with Mach discs. Numerical results are compared with available experimental data and with previously published data. An oscillating phenomenon was observed in the case of free jets operating at sonic exit Mach number and in another case of impingement of under‐expanded jets on a flat plate.
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The inhibition of corrosion of Al‐Cu (4%) alloy B26S in decinormal solutions of phosphoric acid by different amines has been studied. The efficiency of the inhibitors increases in…
Abstract
The inhibition of corrosion of Al‐Cu (4%) alloy B26S in decinormal solutions of phosphoric acid by different amines has been studied. The efficiency of the inhibitors increases in the order: triethylamine, di‐cyclohexylamine, diethylamine, cyclohexylamine, di‐n‐propylamine, isopropylamine, ethylenediamine, trimethylamine, n‐butylamine, dimethylamine, ethylamine, hexamine, n‐propylamine, methylamine. At constant acid concentration, the inhibitor efficiency increases with increase in the concentration of the inhibitor whereas at constant inhibitor concentration the efficiency decreases with increase in the concentration of the acid. Very little correlation appears to exist between either the pKb values or the molecular weight and the extent of inhibition. Maximum inhibition is achieved in those cases where the pH of the inhibited solution lies in the non‐corrosive range (4.5–8.5).
Nilüfer Koçtürk, Sinem Cankardaş, Zeynep Sofuoğlu and Betül Ulukol
Culture significantly influences individuals' lives and shapes their behaviour in an ecological framework. In this chapter, we examine the issue of children's participation in…
Abstract
Culture significantly influences individuals' lives and shapes their behaviour in an ecological framework. In this chapter, we examine the issue of children's participation in research about child abuse and neglect (CAN) in the context of Turkey – a country that bridges the Asian and European continents. This study was based on a review examining studies on CAN in Turkey. Thus, the main goal was to find cultural explanations for the scarcity of participatory research with children in the field of child maltreatment. A review examining studies on CAN in Turkey found that no study included children victims of CAN or explored why children victims of CAN have not been participating in research. Therefore, we analysed ecological factors influencing the participation of children in CAN studies and interpreted the findings based on our observations as experts in this field. The analysis indicated that causes are not only due the characteristics of the caregivers and children but also result from the interaction of various environmental and systemic factors. Recommendations for politicians and researchers to increase children's participation in research are discussed.
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P.S. Desai and R.T. Vashi
The purpose of this paper is to investigate the effect that different concentrations of the inhibitor sulphathiazole have on the corrosion of aluminum in 0.01, 0.05 and 0.10 M…
Abstract
Purpose
The purpose of this paper is to investigate the effect that different concentrations of the inhibitor sulphathiazole have on the corrosion of aluminum in 0.01, 0.05 and 0.10 M trichloroacetic acid (TCA), and to elucidate the mechanisms of inhibition for this system.
Design/methodology/approach
Gravimetric measurements and galvanostatic polarization were used to investigate the effect of sulphathiazole on the corrosion of aluminum in TCA solution. The findings were used to determine the corrosion rates and efficiencies of the inhibitor at different concentrations.
Findings
The corrosion rate of aluminum decreased with increasing inhibitor concentrations and the efficiency of inhibition increased with increasing concentration of inhibitor up to almost 89 percent in 0.01 M TCA and up to 65.87 percent in 0.10 M TCA. The concentrations of inhibitor were in the range of 5‐20 mM. Absorption of the inhibitor was onto the aluminum surface and consistent with the Langmuir adsorption isotherm. A plot of log (θ/1−θ) versus log C gave a straight line, which suggests that the inhibitor covers both the anodic and cathodic regions. From the plot of the isotherm, it was observed that one inhibitor molecule occupies more than one active site. The mean ΔGads0 values were negative almost in all cases, indicating that the adsorption was spontaneous and that the mechanism of adsorption was physical – i.e. electrostatic attraction. Polarization data revealed that the inhibitor functions as a mixed inhibitor.
Originality/value
The paper deals with the inhibition of corrosion of 2S commercially pure aluminum in 0.01, 0.05 and 0.10 M solutions of TCA. To date, not much detailed information has been generated about this problem.
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E.E. Oguzie, G.N. Onuoha and A.I. Onuchukwu
To investigate the inhibitive effect of Congo red dye (CR) for aluminium corrosion in strong alkaline solutions and evaluate the synergistic effect of halide ions on the…
Abstract
Purpose
To investigate the inhibitive effect of Congo red dye (CR) for aluminium corrosion in strong alkaline solutions and evaluate the synergistic effect of halide ions on the inhibition efficiency.
Design/methodology/approach
Corrosion rates of aluminium test coupons were determined by gravimetric technique at 30 and 60°C. Inhibition efficiencies of the additives (0.01‐5.0 mM CR and 5.0 mM CR+0.5 mM halides) were evaluated by comparing corrosion rates of the test coupons in 2 M KOH solution in the absence and presence of the additives.
Findings
CR inhibited aluminium corrosion in 2 M KOH by physical adsorption of the dye molecules on the corroding metal surface. Maximum efficiency at 30 and 60°C was 31.72 and 19.32 per cent, respectively. Dye adsorption was enhanced in the presence of halides in the order KCl < KBr < KI, with KI increasing efficiency up to 48.63 and 41.70 per cent at 30 and 60°C, respectively.
Research limitations/implications
Further studies to involve variation of dye and halide concentrations for CR+halide systems to determine the best combination for optimum inhibition synergism.
Originality/value
This paper forms part of an extensive database on the inhibition characteristics of organic dyes for corrosion of different metals in various aggressive environments. This is to serve as a guide to possible applications in metal‐surface anodizing and as additives in surface coatings for service in different environments.
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Andrea Da Ronch, Marco Panzeri, M. Anas Abd Bari, Roberto d’Ippolito and Matteo Franciolini
The purpose of this paper is to document an efficient and accurate approach to generate aerodynamic tables using computational fluid dynamics. This is demonstrated in the context…
Abstract
Purpose
The purpose of this paper is to document an efficient and accurate approach to generate aerodynamic tables using computational fluid dynamics. This is demonstrated in the context of a concept transport aircraft model.
Design/methodology/approach
Two designs of experiment algorithms in combination with surrogate modelling are investigated. An adaptive algorithm is compared to an industry-standard algorithm used as a benchmark. Numerical experiments are obtained solving the Reynolds-averaged Navier–Stokes equations on a large computational grid.
Findings
This study demonstrates that a surrogate model built upon an adaptive design of experiments strategy achieves a higher prediction capability than that built upon a traditional strategy. This is quantified in terms of the sum of the squared error between the surrogate model predictions and the computational fluid dynamics results. The error metric is reduced by about one order of magnitude compared to the traditional approach.
Practical implications
This work lays the ground to obtain more realistic aerodynamic predictions earlier in the aircraft design process at manageable costs, improving the design solution and reducing risks. This may be equally applied in the analysis of other complex and non-linear engineering phenomena.
Originality/value
This work explores the potential benefits of an adaptive design of experiment algorithm within a prototype working environment, whereby the maximum number of experiments is limited and a large parameter space is investigated.
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This study aims to understand the experiences of Brazilian nurse auditors in the practice of their profession, exploring the importance, challenges, rewards and strategies related…
Abstract
Purpose
This study aims to understand the experiences of Brazilian nurse auditors in the practice of their profession, exploring the importance, challenges, rewards and strategies related to the occupation.
Design/methodology/approach
This is a qualitative descriptive study conducted with 44 nurse auditors. An online, open-ended questionnaire was used. Thematic content analysis was performed.
Findings
Five themes were identified: (1) functions of a nurse auditor; (2) skills required for a nurse auditor; (3) learning to be a nurse auditor; (4) advantages of being a nurse auditor and (5) challenges faced by a nurse auditor. Also, a total of 16 subthemes were presented.
Research limitations/implications
The study critically examined essential aspects of auditing through the lens of nurse auditors, addressing a relevant topic. However, limitations must be acknowledged, including the use of self-report questionnaires, regional representation disparities, the scarcity of international articles on the topic and potential researcher bias.
Practical implications
The study underscores the importance of increasingly integrating nurse auditors into the workforce while emphasizing the need to enhance the capacitation of these professionals through theoretical and practical education. It highlights the significance of educating other multidisciplinary team members about the nurse auditor’s crucial role in fostering teamwork and ensuring the quality of healthcare services.
Originality/value
To the best of the author’s knowledge, this is the first study conducted with Brazilian nurse auditors, exploring crucial aspects of auditing from the perspective of these professionals. Understanding the critical role of nurse auditors in maintaining and improving healthcare quality can enhance public trust in healthcare systems.
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Yu‐Hsiu Kao, Yi‐Ching Huang, Pei‐Ying Chen and Kuo‐Ming Wang
The purpose of this paper is to investigate the effects of an exercise education intervention on exercise behavior, depression and fatigue status of chronic kidney disease (CKD…
Abstract
Purpose
The purpose of this paper is to investigate the effects of an exercise education intervention on exercise behavior, depression and fatigue status of chronic kidney disease (CKD) patients.
Design/methodology/approach
This was a pilot study using an exercise education program as an intervention for CKD patients. The authors used the transtheoretical model (TTM) to design the exercise education programs. A total of 94 subjects diagnosed with CKD at a medical center in Taiwan participated in this quasi‐experimental study. Subjects were randomly divided into the experimental group (n=45) and the control group (n=49). The education program included written materials and teaching activities designed to encourage participants to initiate and continue regular exercise. Both groups took the pre‐test and post‐test containing a depression inventory, a fatigue scale and an exercise behavior inventory.
Findings
The findings indicated that changes in the exercise behavior, depression and fatigue status of the experimental group were statistically significant after the exercise education intervention compared with the control group.
Originality/value
The paper demonstrates that exercise education intervention can be administered by nursing staff, or a health educator, to encourage patients to exercise in order to enhance their quality of care.
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Jing Lin, Wei Wang, Xiufang Wen, Zhi‐Qi Cai, Pihui Pi, Da‐feng Zheng, Jiang Cheng and Zhuoru Yang
The purpose of this paper is to study thermal stability, curing kinetics and physico‐chemical properties of polyurethanes systems for application in in‐mould decoration (IMD) ink.
Abstract
Purpose
The purpose of this paper is to study thermal stability, curing kinetics and physico‐chemical properties of polyurethanes systems for application in in‐mould decoration (IMD) ink.
Design/methodology/approach
The thermal stability of three Polyurethane (Pu) systems A, B, C were evaluated by thermogravimetric analysis (TGA). The kinetic parameters of the curing reaction of Pu system C were calculated using non‐isothermal curing kinetics analysis, including the activation energy Ea, the reaction rate constant K(T), the reaction order n, the initial curing temperature (Ti), the peak temperature (Tp), and the finishing temperature (Tf). Additionally, physico‐chemical properties were also evaluated such as flexibility, impact resistance, pencil hardness, adhesive attraction and solvent resistance.
Findings
TGA showed that thermal decomposition temperature T5 (5 wt.% weight loss), T10 (10 wt.% weight loss) and Tend (decomposition termination temperature) of Pu system C was 344°C, 363°C, and 489°C, respectively. T5, T10, Tend increased by 77°C, 61°C, 4°C, respectively, and the char yield at 600°C increased by 25.1 wt.% comparing with Pu system B. Curing kinetics analysis showed that Ea of Pu system C was 62.29 KJ/mol, 65.98 KJ/mol and 65.95 KJ/mol by Kissinger, Flynn‐Wall‐Ozawa and Ozawa method, respectively. The order of the curing reaction (n=0.90) demonstrated that it was a complex reaction. Moreover, Pu system C exhibited good physico‐chemical properties. The results showed that Pu system C was suitable to apply into IMD ink.
Research limitations/implications
The TGA analysis, curing kinetics analysis and evaluation of physico‐chemical properties provided a simple and practical solution to study suitable resins for IMD ink application.
Practical implications
IMD ink for heat transfer printing technology is highly efficient, relatively low cost, clean and environmentally safe. It has been widely applied into medical and pharmaceutical products, electronic devices, telecommunication equipment, computer parts, appliance panels, automotive parts, etc.
Originality/value
In this paper, the thermal stability and curing kinetics of Pu for IMD ink are reported for the first time. The paper gives very interesting and important information about thermal stability, curing kinetics and properties of Pu coating system for IMD ink application.
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This paper attempts to evaluate the transverse stresses that are generated within the interface between two layers of laminated composite and sandwich laminates by using Cℴ finite…
Abstract
This paper attempts to evaluate the transverse stresses that are generated within the interface between two layers of laminated composite and sandwich laminates by using Cℴ finite element formulation of higher‐order theories. These theories do not require the use of a fictitious shear correction coefficient which is usually associated with the first‐order Reissner‐Mindlin theory. The in‐plane stresses are evaluated by using constitutive relations. The transverse stresses are evaluated through the use of equilibrium equations. The integration of the equilibrium equations is attempted through forward and central direct finite difference techniques and a new approach, named as, an exact surface fitting method. Sixteen and nine‐noded quadrilateral Lagrangian elements are used. The numerical results obtained by the present approaches in general and the exact surface fitting method in particular, show excellent agreement with available elasticity solutions. New results for symmetric sandwich laminates are also presented for future comparisons.