Investigation of heavy metals in the Persian Gulf pearl oyster Pinctada radiata by using atomic absorption spectroscopy

Bioaccumulation of seven heavy metals (Zn, Cu, Fe, Cd, Pb, Ni, Mn) were determined in the Persian Gulf pearl oyster "Pinctada radiata" collected from major pearl oyster beds of Lavan and Handurabi Islands and Nakhiloo port during six months, winter of 1994 and spring of 1995, by spectroscopy, considering their environmental condition such as : salinity, pH, dissolved oxygen and transparency. Three ways analysis of variance and mean comparison tests, have been used to determine the relationship between concentration of metals and factors including time sampling, sites and size of samples

Hydrothermal Synthesis of Zirconia Nanoparticles from Commercial Zirconia

AbstractRecently, it was observed that nanostructured zirconia (ZrO2) powder exhibits enhanced performance in many applications. In this study, a hydrothermal method was used for the synthesis of nano-crystalline ZrO2 powder from a fully monoclinic commercial zirconia. The products were characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results of SEM showed that after hydrothermal treatment under alkali condition, a different morphology from the commercial zirconia was obtained and XRD results showed that moreover to monoclinic phase (28%), cubic and tetragonal phases (72%) formed. According to TEM observations and XRD analysis, it was found that the nano-sized zirconia has an average particles size of 15-30nm

Governance gaps in eradicating forced labor: from global to domestic supply chains

A growing body of scholarship analyzes the emergence and resilience of forced labor in developing countries within global value chains (GVCs). However, little is known about how forced labor arises within domestic supply chains concentrated within national borders, producing products for domestic consumption. We conduct one of the first studies of forced labor in domestic supply chains, through a cross-industry comparison of the regulatory gaps surrounding forced labor in the United Kingdom. We find that understanding the dynamics of forced labor in domestic supply chains requires us to conceptually modify the GVC framework to understand similarities and differences across these contexts. We conclude that addressing the governance gaps that surround forced labor will require scholars and policymakers to carefully refine their thinking about how we might design operative governance that effectively engages with local variation

New insight into the informal patients' payments on the evidence of literature: A systematic review study

Background: Nowadays, a growing literature reveals how patients use informal payments to seek either better treatment or additional services, but little systematic review has been accomplished for synthesizing the main factors. The purpose of this study was to analyze the content of literatures to demonstrate the factors for informal patient payments. Methods: In this systematic review study, PubMed, Web of Science, Wiley Online Library, Science Direct, Ovid, Scopus, and Iranian databases were investigated without time limitation for eligible English and Persian studies. Achieved data were analyzed using content analysis approach and MAXQDA 10 software. Results: Themes related to informal payments in external context of health system were demographic features of health service consumers, patient's personality features and social & cultural backgrounds of the community. Health system challenges' themes were about stewardship weakness, and sustainable financing and social protection weakness. These were followed by human resources' organizational behavior challenges, drugs, medical products, and services delivery provision process challenges and finally change management weakness for reducing and dealing with IPs. Conclusion: It appears that improving the quality of health care services and accurate monitoring of delivery processes, along with performing some strategies for regulating payroll and medical tariffs, strict rules and regulations and improving health staff motivation, would be effective ways against informal payments. Improving the health insurance contribution, promoting transparency & accountability in health system especially in financing, identify precise control mechanism, using empower patient/public related approach, modifying community perception, reinforcing social resistance to unofficial payments and rebuilt lost social capital in health care are some of the other recommendations in this field. To practice these strategies, a comprehensive and systemic vision and approach is needed, however, the key point is that before applying any strategy the impact of this strategy on access, efficiency, equity, and other health systems' goals and policies should be investigated due to the consideration. © 2020 The Author(s)

Role of mindfulness, psychological flexibility and integrative self-knowledge on psychological well-being among the university students

Background: Studies has shown the effect on environmental conditions on psychological well-being. In this regard, psychological characteristics have an important role. This study aimed to investigate the role of mindfulness, psychological flexibility and integrative self -knowledge amonge the university students. Material and Methods: This cross-sectional study was performed on the students of Kashan university of medical sciences (n=300) and based on quota sampling, a number of students (n=241) were selected based on the faculty and the major of the study. The administered tools were Ryff scale of psychological well-being (RSPWB-18), mindfulness (MAAS), acceptance and actions (AAQ-II) questionnaires and integrative self-knowledge scale (ISKS). Finally the data were analyzed using correlation and stepwise regression. Results: Pearson correlation disclosed a positive and considerable relation between mindfulness, integrative self-knowledge, psychological flexibility and psychological well-being. In addition, the findings showed significant role of mindfulness, integrative self-knowledge and psychological flexibility to predict the psychological well-being of the students; so these variables can predict 21 of psychological wellbeing changes. Conclusion: This study disclosed that the mindfulness, psychological flexibility and integrative self -knowledge can in part specify the variance of psychological well-being

Plastic-damage smeared crack model to simulate the behaviour of structures made by cement based materials

This work proposes a constitutive model to simulate nonlinear behaviour of cement based materials subjected to different loading paths. The model incorporates a multidirectional fixed smeared crack approach to simulate crack initiation and propagation, whereas the inelastic behaviour of material between cracks is treated by a numerical strategy that combines plasticity and damage theories. For capturing more realistically the shear stress transfer between the crack surfaces, a softening diagram is assumed for modelling the crack shear stress versus crack shear strain. The plastic damage model is based on the yield function, flow rule and evolution law for hardening variable, and includes an explicit isotropic damage law to simulate the stiffness degradation and the softening behaviour of cement based materials in compression. This model was implemented into the FEMIX computer program, and experimental tests at material scale were simulated to appraise the predictive performance of this constitutive model. The applicability of the model for simulating the behaviour of reinforced concrete shear wall panels submitted to biaxial loading conditions, and RC beams failing in shear is investigated.The authors wish to acknowledge the FCT financial support provided by the Portuguese Foundation for Science and Technology in the scope of the SlabSys-HFRC research project, with reference PTDC/ECM/120394/2010

Behaviour of GFRP-steel reinforced I shape beams with steel fibers as shear reinforcement

This paper evaluates the possibility of developing prefabricated beams without stirrups by using fiber reinforcement for increasing the concrete shear capacity, and a hybrid flexural reinforcement system composed of glass fiber reinforced polymer (GFPR) and steel rebars. A high compressive strength and high post-cracking tensile capacity steel fiber reinforced self-compacting concrete (SFRSCC) was developed, aiming at supressing the need of steel stirrups in this type of beams while providing sufficient ductility for structural applications. The experimental results were analysed in terms of failure mode, deformational and cracking behaviour, as well as load carrying capacity. A constitutive model, capable of simulating three types of material nonlinearities simultaneously in an integration point (IP), was used and its predictive performance was assessed by simulating the experimental tests. The numerical approach was then used to assess the potentialities of this material system and structural concept when applied to relatively large span beams.The authors wish to acknowledge the funding provided by project FOATIDE, reference POCI-01- 0145-FEDER-028112

Shear resistance of SFRSCC short-span beams without transversal reinforcements

Corrosion of steel reinforcements, especially stirrups, is considered as one of the most common reasons that shorten the service life of the reinforced concrete structures. This study aims to replace the stirrups of the beams by means of a tailor made steel fiber reinforced self-compacting concrete (SFRSCC). A hybrid flexural reinforcement system was used for all these beams, composed of glass fiber reinforced polymer (GFRP) rebars placed near to the outer surface of the tensile zone and steel reinforcements positioned with higher SFRSCC cover to be protected against the corrosion, which is considered another strategy for enhancing the durability and attending fire issues in terms of safety at ultimate limit states. The effectiveness of varying the prestressing force applied to GFRP bars to improve the shear capacity and failure mode of the designed elements is evaluated. By considering the obtained experimental results, the predictive performance of some analytical formulations for the shear resistance of fiber reinforced concrete beams was assessed. All formulations demonstrate acceptable accuracy for design purposes, but the one proposed by CEB-FIP Model Code 2010 predicts more conservative shear resistance.European Regional Development Fund (FEDER) - “Inotec”, with reference number 23024Portuguese Foundation for Science and Technology (FCT) - “SlabSys-HFRC”, with reference PTDC/ECM/120394/201

Effect of fiber dosage and prestress level on shear behavior of hybrid GFRP-steel reinforced concrete I-shape beams without stirrups

Corrosion of steel reinforcements embedded in concrete elements is generally known as one of the most common reasons that shorten the service life of the structures. The present study aims to contribute in overcoming this problem by replacing steel stirrups as shear reinforcement of concrete beams using a steel fiber reinforced self-compacting concrete (SFRSCC). In the present research the potential of SFRSCC for improving the shear resistance of the beams without stirrups is explored. In order to further reduce the risk of corrosion in this type of beams, a hybrid system of flexural reinforcement composed of a steel strand and GFRP rebars is applied and properly arranged in order to assure a relatively thick concrete cover for the steel reinforcement. The GFRP bars are placed with the minimum cover thickness for providing the maximum internal arm and, consequently, mobilizing efficiently their relatively high tensile strength. The effectiveness of applying different dosages of steel fibers and varying the prestress force to improve the shear behavior of the designed beam are evaluated. By considering the obtained experimental results, the predictive performance of a constitutive model (plastic-damage multidirectional fixed smeared crack model) implemented in a FEM-based computer program, as well as the one from three analytical formulations for estimating shear resistance of the developed beams were assessed. The FEM-based simulations have provided a good prediction of the deformational response and cracking behavior of the tested beams. All the analytical formulations demonstrated acceptable accuracy for design purposes, but the one proposed by CEB-FIP Modal Code 2010 predicts more conservative shear resistance.The first and second authors, respectively, acknowledge the research grant in the ambit of the project “UrbanCrete”, with reference number of 30367, supported by the European Regional Development Fund (FEDER), and “SlabSys-HFRC”, with reference PTCD/ECM/120394/2010, supported by the Portuguese Foundation for Science and Technology (FCT). The authors also thank the collaboration of the following companies: Tensacciaci in the name of Eng. F. Pimenta for the assistance on the application of prestress reinforcements, Sireg and Schoeck for providing the GFRP rebars, Casais to manufacture the moulds, Exporplas for supplying the polypropylene fibers, Secil/Unibetão for providing the Cement, BASF for supplying the superplasticizer and CiviTest for collaborating in producing the specimens