The sequential twinning-transformation induced plasticity effects in a thermomechanically processed high Mn austenitic steel

Different initial microstructures with various bimodal grain size distributions (BGSD) were produced in a high Mn austenitic steel through applying a predetermined set of thermomechanical processing cycles. The corresponding room temperature mechanical properties and the related strain hardening behaviors were assessed using tensile testing method. The results indicated that in the microstructure with high grain size bimodality, the length and amplitude of rapid hardening region was well higher than the others. This was attributed to its higher capability to a'-martensite formation. In addition, the threshold strain to initiate martensitic transformation was shifted to the lower one in the microstructure with higher bimodal grain size distribution. The latter was related to the lower arisen back stresses in the interior regions of the coarser grains. Furthermore, different transformation paths were identified as the BGSD changed. The austenite could directly transform to a'-martensite (¿a') in the microstructure with lower BGSD; in this case the a'-martensite mainly appeared at the intersections of deformation twins. In contrast, in microstructures with higher BGSD, the nucleation occurred at the intersections of e-martensite platelets. The co-existence of these transformation paths provided an extended transformation induced plasticity effect ending to a higher elongation to fracture in the course of deformation. In order to summarize the contribution of various strain hardening mechanisms, a deformation map was also constructed. Accordingly, the enhanced ductility/strength properties were attributed to the sequential operation of extended transformation induced plasticity and twinning induced plasticity effects.Peer ReviewedPostprint (author's final draft

Sensitivity to hydrogen induced cracking, and corrosion performance of an API X65 pipeline steel in H2S containing environment: influence of heat treatment and its subsequent microstructural changes

In this investigation, the effect of microstructural changes and phase equilibria on corrosion behavior and hydrogen induced cracking (HIC) sensitivity of an API X65 pipeline steel was studied. For this purpose, heat treatment was performed at 850 °C, 950 °C, 1050 °C and 1150 °C to engineer the desired microstructure of this pipeline steel. Then, the microstructural evolution was performed by optical microscopy, and Field Emission Scanning Electron Microscopy (FE-SEM) equipped with Energy Dispersive X-Ray Spectroscopy (EDS). Corrosion properties were evaluated in H2S environment by open circuit potential (OCP), Potentiodynamic polarization and Electrochemical Impedance Spectroscopy (EIS). As well, HIC sensitivity of the API X65 pipeline steel was assessed by hydrogen charging of the cathode and immediately conducting the tensile test. Microscopy analyses showed that the microstructure of the steel is ferritic-pearlitic together with the islands of martensite/austenite constituents. Increasing the heat treatment temperature reduced the amount of pearlite and increased ferrite grain size. It also stabilized the ferrite content. Corrosion results indicated that no active layer was formed on the surface of this pipeline steel. Also, increasing the heat treatment temperature increased the corrosion resistance and reduced sensitivity to micro-galvanic localized corrosion. As well, results suggested that the sensitivity to HIC in the API X65 pipeline was substantially increased with increasing the amount of pearlite and reducing the amount of ferrite; i.e. at lower heat treatment temperature.publishedVersio

Smart and biomimetic 3D and 4D printed composite hydrogels: opportunities for different biomedical applications

In recent years, smart/stimuli-responsive hydrogels have drawn tremendous attention for their varied applications, mainly in the biomedical field. These hydrogels are derived from different natural and synthetic polymers but are also composite with various organic and nano-organic fillers. The basic functions of smart hydrogels rely on their ability to change behavior; functions include mechanical, swelling, shaping, hydrophilicity, and bioactivity in response to external stimuli such as temperature, pH, magnetic field, electromagnetic radiation, and biological molecules. Depending on the final applications, smart hydrogels can be processed in different geometries and modalities to meet the complicated situations in biological media, namely, injectable hydrogels (following the sol-gel transition), colloidal nano and microgels, and three dimensional (3D) printed gel constructs. In recent decades smart hydrogels have opened a new horizon for scientists to fabricate biomimetic customized biomaterials for tissue engineering, cancer therapy, wound dressing, soft robotic actuators, and controlled release of bioactive substances/drugs. Remarkably, 4D bioprinting, a newly emerged technology/concept, aims to rationally design 3D patterned biological matrices from synthesized hydrogel-based inks with the ability to change structure under stimuli. This technology has enlarged the applicability of engineered smart hydrogels and hydrogel composites in biomedical fields. This paper aims to review stimuli-responsive hydrogels according to the kinds of external changes and t recent applications in biomedical and 4D bioprinting

Spatial planning for water sustainability projects under climate uncertainty: balancing human and environmental water needs

Societies worldwide make large investments in the sustainability of integrated human-freshwater systems, but uncertainty about water supplies under climate change poses a major challenge. Investments in infrastructure, water regulation, or payments for ecosystem services may boost water availability, but may also yield poor returns on investment if directed to locations where water supply unexpectedly fluctuates due to shifting climate. How should investments in water sustainability be allocated across space and among different types of projects? Given the high costs of investments in water sustainability, decision-makers are typically risk-intolerant, and considerable uncertainty about future climate conditions can lead to decision paralysis. Here, we use mathematical optimization models to find Pareto-optimal satisfaction of human and environmental water needs across a large drought-prone river basin for a range of downscaled climate projections. We show how water scarcity and future uncertainty vary independently by location, and that joint consideration of both factors can provide guidance on how to allocate water sustainability investments. Locations with high water scarcity and low uncertainty are good candidates for high-cost, high-reward investments; locations with high scarcity but also high uncertainty may benefit most from low regret investments that minimize the potential for stranded assets if water supply increases. Given uncertainty in climate projections in many regions worldwide, our analysis illustrates how explicit consideration of uncertainty may help to identify the most effective strategies for investments in the long-term sustainability of integrated human-freshwater systems.The project described in this publication was supported by the Science Applications division of the Southwest Region of the US Fish and Wildlife Service, and by Grant No. G17AP00120, Balancing Water Usage and Ecosystem Outcomes Under Drought and Climate Change: Enhancing an Optimization Model for the Red River, from the United States Geological Survey. Open Access fees paid for in whole or in part by the University of Oklahoma Libraries.Ye

Studying native fishes in Hamadan province

Studying native fishes of Hamadan province have been done in 159 stations from 51 important water resources (wetland, reservoir, spring, river and qanat) using with electric tool, cast-net, seine and gill-net gears from July 2010 to Oct. 2011 and the main aims were species identifying and determining their distribution and abundance in the studied area. In the study, 33411 fish specimens are caught in 257 times of sampling and selected randomly about 8500 individual and laboratory works showed the fish belong to 37 species from 7 families. Cyprinidae with 25, Nemacheilidae with 6 and Sisoridae with 2 species had the most diversity and Cobitidae, Poeciliidae, Salmonidae and Mastacembelidae had only a representative. 31 fish species were native or endemic and 6 species were alien. Fish species existed in all rivers of Ghezelozan and Sirvan sub-basins but there were not any fish in 10 rivers of Ghara-Chai sub-basin and in 6 rivers of Gamasiab sub-basin, too. Also, it was observe 1-3 fish species in 15 rivers, 4-6 fish species in 10 rivers, 7-10 fish species in 5 rivers and more than 10 fish species in 4 main water resources and Gamasiab sub-basin with 32 fish species was the most diversified and Ghezelozan sub-basin with 2 fish species was the least diversified. There were any species to 4 (mostly 1 or 2) fish species in studied qanats in Ghara-Chai and Gamasiab rivers sub-basins. 23 fish species existed in a subbasin, 12 species in 2 sub-basin, Capoeta capoeta in 3 sub-basin and Squalius cephalus in all sub-basins of studied area. Alburnoides nicolausi,Capoeta aculeata and Alburnus mossulensis have had the most frequency. Studying fish abundance showed Oxynoemacheilus argyrogramma with 17.8%, Garra rufa with 12.3%, A. mossulensis with 12.1% and C. aculeata with 10.2 % of total number of caught fish specimens are dominant. S. cephalus, Capoeta damascina, C. aculeata, C. trutta, Chondrostoma regium and A. mossulensis have had sport fishing value but Acanthobrama marmid, Oxynoemacheilus kiabii, Oxynoemacheilus kermanshahensis, Turcinoemacheilus kosswigi, Alburnus caeruleus and Mastacembelus mastacembelus have biodiversity value for being endemic or having limited habitats in Iran

Environmental design solutions for existing concrete flat roofs in low-cost housing to improve passive cooling in western Mexico

The development of real estate in Mexico has largely ruled out the comfort of users that focused on economic matters and made it difficult to make substantial progress in adopting measures to improve indoor environmental quality. Current research projects in Mexico found that roof construction in low-cost housing struggles to meet the requirements of the indoor climate. Passive cooling strategies are techniques to control heat gain and heat dissipation in buildings to maximise the comfort and health of building users while minimising energy use. Passive cooling systems recognize climate conditions and utilise renewable sources of energy such as the sun and wind to provide cooling and ventilation. Therefore, this study aims to develop a green and sustainable solution for existing concrete flat roofs with no major interventions and investments to save energy. The design of a passive device was tested to assess its effectiveness to protect flat roofs from shortwave radiation and to allow for heat dissipation in Mexican buildings. The study used a quantitative approach based on experiments and simulation tests to evaluate design efficiency. The results showed that a perforated device with an opening percentage of 88% and a cavity of 0.05m between the roof and the device provided effective protection. Also, the device with blinds of 45° showed lower operative temperatures within a range of mean values between 0.8°C and 0.9°C compared to a roof with a full shade cover in the hot and humid season. However, the perforated device with blinds of 90° in black colour delivered the best performance compared to other models and recorded a mean value of 1.13°C in the hot sub-humid season. The results revealed the efficiency of the proposed device that can be observed within different geometric configurations, surface properties as well as the use of the nocturnal radiative cooling potential in blocking solar radiation in Mexican buildings

The Effect of Patient Safety Education on Undergraduate Nursing Students� Patient Safety Competencies

: Patient safety is influenced by a set of factors in various levels of the healthcare system. One of the factors affecting patient safety is safety competencies of the nursing students. The current study aimed to evaluate the effect of patient safety education on patient safety competencies of the nursing students. This quasi-experimental study was conducted with a pretest-posttest deign. The levels of patient safety competencies of 50 nursing students were investigated in a nursing school affiliated to large university of medical sciences in the south of Iran in 2019. Data were collected using Health Professional Education in Patient Safety Survey (H-PEPSS). The data were analyzed in SPSS 21 using descriptive statistics and repeated measures ANOVA. The three investigated intervals were significantly different in terms of the total H-PEPSS dimensions, while the lowest was attributed to the dimension �managing safety�. Mean scores of �how broader patient safety issues are addressed in health professional education� and �comfort speaking up about patient safety� significantly increased during the follow-up periods. The educational intervention was partially effective in improving patient safety competencies of the nursing students over long term. © The Author(s) 2020

Outcomes of Effective Integration of Clinical Risk Management Into Health Care From Nurses� Viewpoints: A Qualitative Study

The aim of this study was to explore nurses� experiences and viewpoints about the outcomes of effective integration of clinical risk management (CRM) into health care. This qualitative study was conducted using purposive sampling and semistructured interviews with 19 nurses from three hospitals affiliated with a large medical university. Data were analyzed by the conventional qualitative content analysis method proposed by Lundman and Graneheim. Data analysis reflected the following concepts: improving the quality of services and promoting health, preserving and protecting patient safety, increasing satisfaction, improving staff morale, and improving organizational awareness and vigilance. According to the results, CRM with its positive outcomes can help the development of a patient-oriented culture. The results can be a starting point for further quantitative and qualitative research to explore other strategies, potentials, and capacities of quality improvement activities such as CRM in other contexts and cultures. © The Author(s) 2020