Cement based materials reinforced with recycled steel fibres: mechanical, durability and structural performance

Tese de Doutoramento (Programa Doutoral em Engenharia Civil)Recent research is showing that the addition of Recycled Steel Fibres (RSF) from postconsumed tyres can decrease significantly the brittle behaviour of cement based materials, by improving its toughness and post-cracking resistance. In this sense, Recycled Steel Fibre Reinforced Concrete (RSFRC) seems to have the potential to constitute a sustainable material for structural and non-structural applications. To assess this potential, experimental and numerical research was performed on the use of RSFRC in elements failing in bending and in shear. The values of the fracture mode I parameters of the developed RSFRC were determined by performing inverse analysis with test results obtained in three point notched beam bending tests. To assess the possibility of using RSF as shear reinforcement in Reinforced Concrete (RC) beams, three point bending tests were executed with three series of RSFRC beams flexurally reinforced with a relatively high reinforcement ratio of longitudinal steel bars in order to assure shear failure for all the tested beams. By performing material nonlinear simulations with a computer program based on the Finite Element Method (FEM), the applicability of the fracture mode I crack constitutive law derived from the inverse analysis was assessed for the prediction of the mechanical behaviour of these beams. The performance of the formulation proposed by RILEM TC 162 TDF and CEB-FIP 2010 for the prediction of the shear resistance of fibre reinforced concrete elements was also evaluated. Furthermore, the use of thin cement based (mortar) panels reinforced with relatively high content of RSF for structural reinforcement was explored. The mechanical properties and the durability performance of this Recycled Steel Fibre Reinforced Mortar (RSFRM) were characterised. The panels were produced by using a mixing technique similar to the one is used in the Slurry Infiltrated Fibre Concrete (SIFCon) technology. Then, their potentialities as a shear strengthening solution for RC beams deficiently reinforced in shear were investigated by performing three point bending tests with RC beams of “I” cross section shape (shear strengthened with this type of panels). Advanced numerical simulations and an analytical study were carried out to contribute for a better understanding of the effectiveness of the shear strengthening technique with RSFRM panels.A investigação desenvolvida no passado recente tem demonstrado que a adição de Fibras de Aço Recicladas (FAR) provenientes de pneus usados pode reduzir, de forma significativa, o comportamento frágil dos materiais de matriz cimentícia, melhorando a sua ductilidade e resistência pós-fendilhação. Neste sentido, o Betão Reforçado com Fibras de Aço Recicladas (BRFAR) apresenta-se como um material de caráter sustentável tanto para aplicações estruturais como não estruturais. Para melhor avaliar este potencial, desenvolveu-se investigação experimental e numérica relativa à utilização do BRFAR em elementos de betão sujeitos a rotura por flexão e por corte. Os parâmetros de fratura tipo I do BRFAR desenvolvido foram obtidos recorrendo a análise inversa dos resultados experimentais de ensaios de flexão, em três pontos, de vigas entalhadas. Para avaliar a potencialidade de utilização de FAR no reforço ao corte de vigas em Betão Armado (BA), foram realizados ensaios de flexão (três pontos) em três séries de vigas em BRFAR reforçadas à flexão com uma elevada percentagem de armadura longitudinal de forma a assegurar uma rotura por corte da totalidade das vigas ensaiadas. Através de simulações numéricas em regime não linear material efetuadas recorrendo a ferramentas baseadas no Método dos Elementos Finitos (MEF), a aplicabilidade das leis constitutivas relativas ao Modo I de fratura, obtidas recorrendo a análise inversa, foi avaliada na previsão do comportamento mecânico dessas vigas. A eficácia das formulações propostas pelo RILEM TC 162 TDF e pelo CEB-FIP 2010 para a previsão da resistência ao corte de elementos em betão reforçados com fibras foi, também, avaliada. Além disso, a utilização de painéis finos constituídos por material de base cimentícia (argamassa) reforçados com uma elevada quantidade de FAR para reforço estrutural foi explorada. As propriedades mecânicas e de durabilidade desta Argamassa Reforçada com Fibras de Aço Recicladas (ARFAR) foram caraterizadas. Os painéis foram produzidos recorrendo à técnica de mistura utilizada no fabrico dos Slurry Infiltrated Fibre Concrete (SIFCon). Seguidamente, as potencialidades da sua utilização como solução de reforço ao corte de vigas em BA com défice de reforço ao corte foram avaliadas recorrendo a ensaios de flexão (três pontos) de vigas de betão armado com secção em I (reforçadas ao corte com os painéis desenvolvidos). Paralelamente, realizaram-se simulações numéricas avançadas e um estudo analítico com o intuito de contribuir para um maior conhecimento relativo à eficiência da utilização desta técnica de reforço com painéis finos em ARFAR

Developing and Evaluating Clinical Written Assignment in Clinical Teaching for the Senior B.S. Nursing Students: An action research

Introduction: In a four-year undergraduate level , the nursing students have to get prepared in the patients education, designing care plans, applying nursing processes and exercise the clinical decisions, in addition to learning practical skills. Therefore, multiple clinical teaching strategies in nursing must be applied. In this study the sheets for the mentioned fields were designed and used. Methods: In this action research in Tabriz University of Medical Sciences, 64 nursing senior students and related instructors participated. Clinical written assignment included the patient’s health condition sheet, tables showing the used medicines and the precautions, the clinical and paraclinical tests and the results, identifying the patient problems, designing and implementing care plan and writing nursing reports with SOAPIE method. The instructors’ viewpoints were achieved through the group discussions and their notes taken. The perceived competency of the students was obtained through a questionnaire. The qualitative data was analyzed by the content analysis and quantitative using SPSS. Results: Both the students and the instructors agreed with the clinical written assignment. The desired care competency of the students before and after assignment was statistically significant (p<0.05). According to the instructors, intervention was useful for the senior students who have passed the courses needed for completing and using the different parts of these forms. Conclusion: Since a need is always felt in the trends of the nursing clinical teaching, the researchers recommend the clinical written assignment and their application along with other strategies for senior nursing students in clinical teaching

From nurse to service-user: a personal cancer narrative.

This article presents a ‘snapshot’ of my experience of being a nurse who became a service-user with breast cancer. It begins by outlining the Humanisation of Healthcare Framework (Todres et al, 2009), which is a values-based context which can be used to underpin daily care. Generic suggested applications for each of the dimensions of the framework are provided. This framework is then used to contextualise my experience of receiving my diagnosis and the ensuing chemotherapy. Using the examples I present from my personal narrative, I make some recommendations for “small actions” that can contribute to more humanised and person-centred care. I also hope that this narrative prompts reflection by the reader and thus enhances the quality of care given to others

Cement-Based Mortar Panels Reinforced with Recycled Steel Fibers in Flexural Strengthening of Concrete Beams

The effectiveness of a strengthening technique devised for the concrete beams subjected to bending is presented in this study, where recycled-steel fiber-reinforced mortar (RSFRM) panels are used as an eco-friendly replacement for ordinary steel fibers. Different mix designs for RSFRM are first investigated experimentally by testing 160 × 400 × 400 mm3 notched beam-like specimens in 3-point bending, while 100 × 100 × 100 mm3 cubes are tested in compression, to optimize the mix design. Finite element (FE) analyses are carried out on strengthened and non-strengthened beams to investigate the effectiveness of the proposed strengthening technique based on RSFRM panels. Starting from the tests on notched beams, an inverse FE analysis is used to optimize the RSFRM’s parameters to be implemented into the numerical model. The results show that applying RSFRM panels not only markedly increases the load-bearing capacity of the beams (up to 3.19 times with 3% of fibers by volume), but also changes their fracture mechanism from brittle to ductile fracture

An Investigation on Adoption of Socio-Culturally Based Teaching Strategies Among Iranian Clinical Nurse Educators

Background: In today’s complex healthcare environments, the traditional teaching strategies and learning models are unable to prepare learners to confront with rapid changes. Some education scholars believe that the teaching strategies based on socioculturally theory are more responsible and efficient. Objectives: The present study was conducted to investigate socio-culturally-based teaching strategies being adopted or assigned by Iranian clinical nurse educators as high priorities. Patients and Methods: A descriptive study was conducted on 38 nurse educators from two nursing and midwifery faculties in Tabriz and Urmia, Iran. Data were collected over a period of 2 months in 2010 using the Phillip’s Adoption Appraisal Instrument, developed by Bonk & Kim. The instrument items have been ranked on a 4-point Likert-type scale and ordered in 10 subscales. The data were analyzed using SPSS software version 13.0. The overall mean, standard deviation, and confidence interval 95% were calculated for each subscale to determine the rank distribution of subscales. Results: All strategies were known as a moderate adoption (2.72 ± 0.44 of 4), however prioritizing in adoption of socio-culturally-based teaching strategies from clinical nurse educators’ viewpoints indicated that 60% of strategies were evaluated as the most adopted strategies, 10% as the least, and the other 30% in moderate mode. Conclusions: Due to the importance of socio-culturally-based theory strategies in clinical settings and the moderate adoption of strategies from clinical nurse educators’ viewpoints,educational planners and policymakers should prepare required prepositions to progress the adoption and the usage of these strategies

Enhancement of Modeling Phased Anaerobic Digestion Systems through Investigation of Their Microbial Ecology and Biological Activity

Anaerobic digestion (AD) is widely used in wastewater treatment plants for stabilisation of primary and waste activated sludges. Increasingly energy prices as well as stringent environmental and public health regulations ensure the ongoing popularity of anaerobic digestion. Reduction of volatile solids, methane production and pathogen reduction are the major objectives of anaerobic digestion. Phased anaerobic digestion is a promising technology that may allow improved volatile solids destruction and methane gas production. In AD models, microbially-mediated processes are described by functionally-grouped microorganisms. Ignoring the presence of functionally-different species in the separate phases may influence the output of AD modeling. The objective of this research was to thoroughly investigate the kinetics of hydrolysis, acetogenesis (i.e., propionate oxidation) and methanogenesis (i.e., acetoclastic) in phased anaerobic digestion systems. Using a denaturing gradient gel electrophoresis (DGGE) technique, bacterial and archaeal communities were compared to complement kinetics studies. Four phased digesters including Mesophilic-Mesophilic, Thermophilic-Mesophilic, Thermophilic-Thermophilic and Mesophilic-Thermophilic were employed to investigate the influence of phase separation and temperature on the microbial activity of the digestion systems. Two more digesters were used as control, one at mesophilic 35 0C (C1) and one at thermophilic 55 0C (C2) temperatures. The HRTs in the first-phase, second-phase and single-phase digesters were approximately 3.5, 14, and 17 days, respectively. All the digesters were fed a mixture of primary and secondary sludges. Following achievement of steady-state in the digesters, a series of batch experiments were conducted off-line to study the impact of the digester conditions on the kinetics of above-mentioned processes. A Monod-type equation was used to study the kinetics of acetoclastic methanogens and POB in the digesters, while a first-order model was used for the investigation of hydrolysis kinetics. Application of an elevated temperature (55 0C) in the first-phase was found to be effective in enhancing solubilisation of particulate organics. This improvement was more significant for nitrogen-containing material (28%) as compared to the PCOD removal (5%) when the M1 and T1 digesters were compared. Among all the configurations, the highest PCOD removal was achieved in the T1T2 system (pvalue<0.05). In contrast to the solubilisation efficiencies, the mesophilic digesters (C1, M1M2 and T1M3) outperformed the thermophilic digesters (C2, T1T2 and M1T3) in COD removal. The highest COD removal was obtained in the T1M3 digestion system, indicating a COD removal efficiency of 50.7±2.1%. The DGGE fingerprints from digesters demonstrated that digester parameters (i.e., phase separation and temperature) influenced the structure of the bacterial and archaeal communities. This resulted in distinct clustering of DGGE profiles from the 1st-phase digesters as compared to the 2nd-phase digesters and from the mesophilic digesters as compared to the thermophilic ones. Based on the bio-kinetic parameters estimated for the various digesters and analysis of the confidence regions of the kinetic sets (kmax and Ks), the batch experiment studies revealed that the kinetic characteristics of the acetoclastic methanogens and POB developed in the heavily loaded digesters (M1 and T1) were different from those species developed in the remaining mesophilic digesters (M2, M3 and C1). As with the results from the mesophilic digesters, a similar observation was made for the thermophilic digesters. The species of acetoclastic methanogens and POB within the T1 digester had greater kmax and Ks values in comparison to the values of the T3 and C2 digesters. However, the bio-kinetic parameters of the T2 digester showed a confidence region that overlapped with both the T1 and T3 digesters. The acetate and propionate concentrations in the digesters supported these results. The acetate and propionate concentrations in the M1 digesters were, respectively, 338±48 and 219±17 mgCOD/L, while those of the M2, M3 and C1 digesters were less than 60 mg/L as COD. The acetate and propionate concentrations were, respectively, 872±38 and 1220±66 in T1 digester, whereas their concentrations ranged 140-184 and 209-309 mg/L as COD in the T2, T3 and C2 digesters. In addition, the DGGE results displayed further evidence on the differing microbial community in the 1st- and 2nd-phase digesters. Two first-order hydrolysis models (single- and dual-pathway) were employed to study the hydrolysis process in the phased and single-stage digesters. The results demonstrated that the dual-pathway hydrolysis model better fit the particulate COD solubilisation as compared to the single-pathway model. The slowly (F0,s) and rapidly (F0,r) hydrolysable fractions of the raw sludge were 36% and 25%, respectively. A comparison of the estimated coefficients for the mesophilic digesters revealed that the hydrolysis coefficients (both Khyd,s and Khyd,r) of the M1 digester were greater than those of the M2 and M3 digesters. In the thermophilic digesters it was observed that the Khyd,r value of the T1 digester differed from those of the T2, T3 and C2 digesters; whereas, the hydrolysis rate of slowly hydrolysable matter (i.e., Khyd,s) did not differ significantly among these digesters. The influence of the facultative bacteria, that originated from the WAS fraction of the raw sludge, and/or the presence of hydrolytic biomass with different enzymatic systems may have contributed to the different hydrolysis rates in the M1 and T1 digesters from the corresponding mesophilic (i.e, M2 and M3) and thermophilic (i.e., T2 and T3) 2nd-phase digesters

Sexual Function in Breastfeeding Women in Family Health Centers of Tabriz, Iran, 2012

Introduction:There are conflicting evidences about the effects of breastfeeding on postpartum maternal sexual functioning. With regard to the methodological weaknesses of previous studies and cultural differences affecting their issue, the present study aims to evaluate sexual functions of lactating women and its components. Methods:This is a descriptive study in which 200 eligible postpartum women were selected from eight health centers of Tabriz (25 from each center). The eligible women were called and invited to attend the health center. The evaluation was performed using the Persian version of normalized questionnaire of the Female Sexual Function Index (FSFI). The participants’ sexual function scores above 28 were considered desirable (regarding the cut-off point mentioned in the Persian version of the questionnaire). Results:Almost all of the lactating women suffered from sexual dysfunctions. Regarding the sexual performance’s components the lowest scores were for libido and sexual arousal. Conclusion:According to the findings of the studies, in order to prevent the effects of sexual dysfunction on lactating women and their family members it is necessary to develop sexual health programs in health centers

Recycled steel fibre reinforced concrete failing in bending and in shear

Recent research is showing that the addition of Recycled Steel Fibres (RSF) from wasted tyres can decrease significantly the brittle behaviour of cement based materials, by improving its toughness and post-cracking resistance. In this sense, Recycled Steel Fibre Reinforced Concrete (RSFRC) seems to have the potential to constitute a sustainable material for structural and non-structural applications. To assess this potential, experimental and numerical research was performed on the use of RSFRC in elements failing in bending and in beams failing in shear. The values of the fracture mode I parameters of the developed RSFRC were determined by performing inverse analysis with test results obtained in three point notched beam bending tests. To assess the possibility of using RSF as shear reinforcement in Reinforced Concrete (RC) beams, three point bending tests were executed with three series of RSFRC beams flexurally reinforced with a relatively high reinforcement ratio of longitudinal steel bars in order to assure shear failure for all the tested beams. By performing material nonlinear simulations with a computer program based on the finite element method (FEM), the applicability of the fracture mode I crack constitutive law derived from the inverse analysis is assessed for the prediction of the behaviour of these beams. The performance of the formulation proposed by RILEM TC 162 TDF and CEB-FIP 2010 for the prediction of the shear resistance of fibre reinforced concrete elements was also evaluated.The present study is part of the activities carried out by the Authors within the "EnCoRe" Project (FP7-PEOPLE-2011-IRSES no. 295283; www.encore-fp7-unisa.it) funded by the European Union within the Seventh Framework Programme. The authors wish also to acknowledge the support provided by Civitest and BioSafe companies

Diagenetic factors controlling reservoir quality in the Faraghan Formation (Lower Permian), Darang Field, Southern Iran

The role of diagenesis in affecting (reduction or enhancement) reservoir quality in the Faraghan Formation in Darang #1 well was investigated. The Faraghan Formation is mainly composed of sandstone facies along with minor mudstone and siltstone and grades upward into mixed carbonate –siliciclastic facies and then to Dalan Formation carbonates. Depositional environment of this formation comprises various sub-environments of a delta setting in the lower part of the formation which grades upward into a shallow marine clastic environment in the upper part. The processes enhancing reservoir quality include dissolution of carbonate grains and cements and alteration of feldspar grains. Burial history diagram shows that after deposition during Lower Permain, the formation underwent a rapid burial up to 1000 meters below sea level in Upper Permian. Then a slight uplift (about 100 meters) and gradual burial followed up to Mid- Jurassic. Afterwards the formation experienced a series of rapid and moderate uplift from Mid-Jurassic to Tertiary when the formation uplifted to around 2500 meters above sea level. The suitable conditions resulting in dissolution took place in shallow buried sandstones. These conditions occurred two times during burial history: at the early stages of eodiagenesis and during telodiagenesis. The major processes deteriorating reservoir quality include compaction and cementation. Major cement types include carbonate cements (dolomite, siderite), clay cements (kaolinite, sericite, chlorite), silica cement and pyrite cement. The most abundant cement is the carbonate cement especially dolomite. The dolomite cement occurs as intergranular and poikilotopic forms. The most frequent clay cement is sericite which dominates in sitstones and lithicarenites. Silica cement, where present, fills all the pore spaces. The least frequent cement type is pyrite which is found in two forms of poikilotopic and framboidal. Where it is found in the form of poikilotopic cement, it massively fills the pore spaces and deteriorates the porosity and permeability of the sandstones