TiO 2 nanoparticles in Concrete

Abstract: The purpose of this study is to investigate the compressive strength and workability of concrete by partial replacement of cement with nano-phase TiO 2 particles. TiO 2 nanoparticles with the average diameter of 15 nm were used with four different contents of 0.5%, 0.1%, 1.5% and 2.0% by weight. The results showed that the use of nano-TiO 2 particles up to maximum replacement level of 2.0% produces concrete with improved strength. However, the ultimate strength of concrete was gained at 1.0% of cement replacement. The workability of fresh concrete was decreased by increasing the content of TiO 2 nanoparticles. It is concluded that partial replacement of cement with nanophase TiO 2 particles improves the compressive strength of concrete but decreases its workability

Intensive care unit, cardiac care unit, and emergency department nurses' perceptions of medical device-related pressure injuries: a cross-sectional study

Background Nurses' perception of medical device-related pressure injuries (MDRPIs) may affect their performance, but there is a lack of studies in this area. Purpose The current study aimed to examine intensive care unit (ICU), cardiac care unit (CCU) and emergency department nurses' perception of proper prevention of MDRPIs and care for individuals with such injuries. Methods This descriptive study was conducted in 4 general hospitals in Iran in 2021. All nurses (N = 310) working in ICUs, CCUs and emergency departments of these facilities were invited to complete a researcher-made demographic checklist and an 11-item questionnaire to assess attitudes toward MDRPIs. The questionnaire item responses were scored from 1 (strongly agree) to 5 (strongly disagree) with the total score for the 11 items ranging from 11 to 55. A score of 11 to 25 was categorized as indicating a negative attitude toward proper prevention of MDRPIs and care for such patients; a score of 26 to 40 indicated a neutral attitude, and a score >40 indicated a positive attitude. Results A total of 260 nurses fulfilled the data collection tool. The response rate was 83.8%. The mean total score of attitude toward MDRPIs was 41.7. No significant relationship was observed between the total score of nurses' attitudes and their demographic variables. Of the 260 participants, 159 stated they had not received any trainings on MDRPIs at nursing schools during their education, 212 stated they had not participated in any scientific workshops on MDRPIs, and 167 described their knowledge about the prevention and care of MDRPIs as insufficient. Conclusion Among ICU, CCU, and emergency nurses in Iran, most had a positive attitude toward the prevention and care of MDRPIs, but steps should be taken to offer more opportunities for nurses to increase their knowledge in this area

A Detailed Study of Boost Pressure and Injection Timing on an RCCI Engine Map Fueled with Iso-Octane and N-Heptane Fuels

By using two types of different fuels and changing the ratios of these fuels, Reactivity Controlled Compression Ignition Engine (RCCI) is able to provide a more effective control over combustion phase at different loads and speeds. In a typical RCCI engine which could be considered as a type of homogeneous charge compression ignition (HCCI) engine, a low reactive fuel is injected into the intake port and a high reactive fuel is directly injected into the combustion chamber. In this study, a multi-dimensional model coupled with chemical mechanism is developed to simulate an RCCI engine operation fueled with iso-octane as the low reactive fuel and n-heptane as the high reactive one. Initially, the engine map was derived using different quantities of total above-mentioned fuels at different ratios and then engine inappropriate operating points were detected and improved by changing intake air pressure and injection timing strategies. The improved criteria to extend engine map are ringing intensity limit, NOx formation standard and gross indicated efficiency. It was concluded that high ringing intensity and NOx formation can be reduced by increasing intake air pressure; also badfire and misfire points can get improved by retarding the injection timing

Considerations about the implementation of an autism screening program in Iran from the viewpoints of professionals and parents: a qualitative study

Background: The aims of this study were to explore to explore the viewpoints of parents of children with Autism Spectrum Disorders (ASD) and professionals regarding the implementation of screening programs for ASD, to explore the challenges of the implementation of a universal screening program for ASD in Iran from their viewpoints, and, to explore their recommendations to overcome the potential challenges. Method: This qualitative study was conducted using an inductive content analysis, between June 2018 and December 2018, in East-Azerbaijan province of Iran. Data was collected through in-depth interviews and focus group discussions. The participants were purposively selected among two groups: representatives of health system and representatives of children with ASD. A sample of 32 parents and 30 professionals were recruited in this study. Results: Totally, 9 main themes and 23 sub-themes were extracted in three main areas including: viewpoints of the participants about universal screening for ASD, challenges in implementation of the universal screening program, and participants� recommendations about how to overcome the potential challenges. Main challenges in implementation of the universal screening program included: shortages of ASD screening tools, weakness of the health system, lack of coordination among the ASD service providers, and social and ethical issues. Conclusion: The parents and the professionals had different viewpoints about the implementation of ASD universal screening program in Iran. According to the professionals, there is not enough rational to implement ASD screening program for all children. However, the parents believed that universal screening program is inevitable, and it should be implemented in primary health centers during the early child-care visits. The results of this study open up unspoken issues that could help in initiating the screening program not only in Iran but also in other low- and middle-income countries as well. © 2021, The Author(s)

Additively manufactured multi-morphology bone-like porous scaffolds: experiments and micro-computed tomography-based finite element modeling approaches

Tissue engineering, whose aim is to repair or replace damaged tissues by combining the principle of biomaterials and cell transplantation, is one of the most important and interdisciplinary fields of regenerative medicine. Despite remarkable progress, there are still some limitations in the tissue engineering field, among which designing and manufacturing suitable scaffolds. With the advent of additive manufacturing (AM), a breakthrough happened in the production of complex geometries. In this vein, AM has enhanced the field of bioprinting in generating biomimicking organs or artificial tissues possessing the required porous graded structure. In this study, triply periodic minimal surface structures, suitable to manufacture scaffolds mimicking bone's heterogeneous nature, have been studied experimentally and numerically; the influence of the printing direction and printing material has been investigated. Various multi-morphology scaffolds, including gyroid, diamond, and I-graph and wrapped package graph (I-WP), with different transitional zone, have been three-dimensional (3D) printed and tested under compression. Further, a micro-computed tomography (µCT) analysis has been employed to obtain the real geometry of printed scaffolds. Finite element analyses have been also performed and compared with experimental results. Finally, the scaffolds' behavior under complex loading has been investigated based on the combination of µCT and finite element modeling

Comparison of morphological variations and some biological features of brown trout Salmo trutta fario resident in Chesli and Khorma Rivers in Guilan

The morphological variations and sexual dimorphism of brown trout Salmo trutta morpha fario residual were studied in two rivers, Chesli and Khorma, in western and eastern of Guilan province using 39 morphometric and 13 meristic characteristics. Univariate analysis of variance (One-way ANOVA) revealed significant differences of varying degrees between the means of the two samples for 25 standardized morphometric measurements and six meristic counts, showing relatively high phenotypic variations between the two populations. No significant differences were observed between males and females, indicating that no sexual dimorphism exists in the studied fish. Plotting of discriminant functions, 1 and 2, for morphometric and meristic characteristics revealed completely obvious separation with 100% divergence between the species of the two areas. Only in Chesli River some differences were observed between males and females according to the meristic’ second function, while there were no morphological differences between males and females in Khorma River. On the average, the correctness of assignment of individuals into their original populations based on their morphometric and meristic characteristics was 87.4% and 70.1%, respectively

Comparison of morphological variations and some biological features of brown trout Salmo trutta fario resident in Chesli and Khorma rivers in Guilan

The morphological variations and sexual dimorphism of brown trout Salmo trutta morpha fario residual were studied in two rivers, Chesli and Khorma, in western and eastern of Guilan province using 39 morphometric and 13 meristic characteristics. Univariate analysis of variance (One-way ANOVA) revealed significant differences of varying degrees between the means of the two samples for 25 standardized morphometric measurements and six meristic counts, showing relatively high phenotypic variations between the two populations. No significant differences were observed between males and females, indicating that no sexual dimorphism exists in the studied fish. Plotting of discriminant functions, 1 and 2, for morphometric and meristic characteristics revealed completely obvious separation with 100% divergence between the species of the two areas. Only in Chesli River some differences were observed between males and females according to the meristic’ second function, while there were no morphological differences between males and females in Khorma River. On the average, the correctness of assignment of individuals into their original populations based on their morphometric and meristic characteristics was 87.4% and 70.1 %, respectively

Toward a conceptual framework for the impact of business analytics on organisations

The number of organisations adopting business analytics (BA) has increased over recent years. However, there is limited empirical research focusing on the impact of BA adoption on organisation design. This paper develops a conceptual framework based on information processing theory (IPT) to evaluate BA adoption in organisations. Qualitative case studies are used as the research methodology, and four case organisations have been identified for data collection. Semi-structured interviews with key informants, observation will be conducted, and documents and archival reports will be collected. The analysis of the data will lead to findings that will increase understanding on the impact BA has on the design and performance of organisations and therefore pave the way toward purposeful use of BA technologies in future.Keywords: Business analytics, information processing theory, organisational design, performanc