Effect of Al-alloy composition and foaming temperature on pore size, density and mechanical properties

Sandwich aluminium foams were developed, with in-situ face sheets, by controlled powder forging and rolling. The parameters for forging, rolling and sintering were optimized for dif-ferent combinations of Aluminium (Al), Al-12Si alloy, Al-8Si alloy and flyash. The foaming of the precursor was recorded and the expansion with time was estimated using image analy-sis. The growth of the sandwich could lead to ~350-400% increase in thickness, before melt-ing of the face sheet, compared to the precursor without Al sheet that led to ~ 1000% expan-sion. The density varied between 0.35-0.90 g/cc and the average size of pores varied in the range of 2-5 mm. Compressive properties were evaluated and the total energy absorbed, up to 60% of deformation, was correlated with the density. The relation followed a power law with R2 value of 0.95

Effect of thermomechanical processing schedule on the texture and microstructure of pipeline grade API X80 microalloyed steel

The presence of micro alloying constituents like Ti, Nb in microalloyed steel enhances its mechanical properties through grain size control and precipitation strengthening. The strengthening capability of microalloying additions can be fully utilized by choosing proper thermomechanical processing (TMP) schedule. The TMP schedule needs to be designed based on determination of critical temperatures of transformation in steel including no recrystallisation temperature (i.e ., Tnr) of microalloyed steels. The TMP was carried out on API X80 grade pipeline steel using Gleeble® 3800 Thermal mechanical simulator. The samples were deformed in plain strain condition at three different temperatures (860, 950 and 1050°C) by keeping other deformation parameters constant. The deformation temperature was chosen based on CCT and Tnr determination studies. The deformed samples were examined in EBSD and TEM to obtain the texture and microstructural information. It is also observed that formation of acicular ferrite and bainite microstructures in these steel is very much dependent on the deformation strain levels in the austenite matrix prior to transformation. The grain boundary misorientation angle distribution obtained from EBSD analysis can be a very important parameter to distinguish the different microstructural constituents apart from grain shape and image quality. Effect of thermomechanical processing schedule on the texture and microstructure of pipeline grade API X80 microalloyed steel (PDF Download Available). Available from: https://www.researchgate.net/publication/303524095_Effect_of_thermomechanical_processing_schedule_on_the_texture_and_microstructure_of_pipeline_grade_API_X80_microalloyed_steel [accessed Nov 15 2017]

Responses and screening of white jute (Corchorus capsularis L.) genotypes against salinity stresses

Soil salinity, a serious threat to jute cultivation in saline areas (southern parts) of Bangladesh. Bangladesh Jute Research Institute (BJRI) has developed a moderately salt tolerant White Jute variety (BJRI Deshi pat-8; BJC 2197) in 2013 which can’t grow well in saline areas having more than 8.0 dSm-1 salinity stress. Hence, 23 whitejute accessions and one control variety (BJC 2197) were tested to isolate the salt tolerant accession(s) for hybridization purpose followed by augmented design in farmers’ field having nearly 8.0-9.0 dSm-1 salinity at Patuakhali district during mid-March to mid-August 2019. The experimental plot size was 3.0 m2 (3 m × 1 m) for each genotype having 3 lines of 1.0 m length, plant-plant: 10-15 cm and line- line: 30 cm distance. Soil salinity was recorded during sowing, vegetative and plant maturity stages. In this study, the highest plant height 2.84 m was recorded in Acc. 2750 followed by Acc. 2589 (2.76 m) and Acc. 1779 (2.69 m). The highest fiber yield (9.0 g plant-1) was observed in Acc. 1779 followed by Acc. 2589 (8.40 g plant-1) and Acc. 2750 (8.0 g plant-1). The lowest plant mortality rate (2.5%) was found in Acc.2750 followed by Acc.1779 (6.24%), Acc. 1780 (7.50), Acc. 3556 (11.10%), Acc. 2589 (11.20%) and BJC 2197 (16.5%). Few seeds were germinated in Acc. 3020 and Acc. 3658 but plants were died after 20 days of sowing. Six genotypes of cluster I showed higher diversity in Euclidean cluster analysis. The Acc. 2750, Acc. 1779, Acc. 2589 of cluster I having relative salinity tolerance and good fiber yield capacity would be grown in next year for confirmation as well as hybridization with the existing salinity susceptible variety to develop high yielding white jute variety for saline areas

Understanding patient and family experiences of critical care in Bangladesh and India: What are the priority actions to promote person-centred care?

Patients’ experiences in the intensive care unit (ICU) can enhance or impair their subsequent recovery. Improving patient and family experiences on the ICU is an important part of providing high quality care. There is little evidence to guide how to do this in a South Asian critical care context. This study addresses this gap by exploring the experiences of critically ill patients and their families in ICUs in Bangladesh and India. We elicit suggestions for improvements from patients, families and staff and highlight examples of practices that support person-centred care. This multi-site hospital ethnography was carried out in five ICUs in government hospitals in Bangladesh and India, selected using purposive sampling. Qualitative data were collected using non-participant observation and semi-structured interviews and analysed using reflexive thematic analysis. A total of 108 interviews were conducted with patients, families, and ICU staff. Over 1000 hours of observation were carried out across the five study sites. We identified important mediators of patient and family experience that span many different aspects of care. Factors that promote person-centred care include access to ICU for families, support for family involvement in care delivery, clear communication with patients and families, good symptom management for patients, support for rehabilitation, and measures to address the physical, environmental and financial needs of the family. This study has generated a list of recommendations that can be used by policy makers and practitioners who wish to implement person-centred principles in the ICU

Manufacturing and Supply Chain Flexibility: Building an Integrative Conceptual Model Through Systematic Literature Review and Bibliometric Analysis

The purpose of this study is twofold: first, to establish the current themes on the topic of manufacturing and supply chain flexibility (MSCF), assess their level of maturity in relation to each other, identify the emerging ones and reflect on how they can inform each other, and second, to develop a conceptual model of MSCF that links different themes connect and highlight future research opportunities. The study builds on a sample of 222 articles published from 1996 to 2018 in international, peer-reviewed journals. The analysis of the sample involves two complementary approaches: the co-word technique to identify the thematic clusters as well as their relative standing and a critical reflection on the papers to explain the intellectual content of these thematic clusters. The results of the co-word analysis show that MSCF is a dynamic topic with a rich and complex structure that comprises five thematic clusters. The value chain, capability and volatility clusters showed research topics that were taking a central role in the discussion on MSCF but were not mature yet. The SC purchasing practices and SC planning clusters involved work that was more focused and could be considered more mature. These clusters were then integrated in a framework that built on the competence–capability perspective and identified the major structural and infrastructural elements of MSCF as well as its antecedents and consequences. This paper proposes an integrative framework helping managers keep track the various decisions they need to make to increase flexibility from the viewpoint of the entire value chain

Hot Deformation Behaviour of a Nb-Mo Linepipe Steel

In linepipe steels, strength and toughness are tailored not only by designing microalloyed compositions but also by controlling hot working process, in order to obtain homogenized and refined microstructure. In the present study, microalloyed steel akin to X80 grade linepipe composition was investigated to examine the effect of hot deformation conditions on the flow behaviour. The isothermal hot compression experiments were carried out on Gleeble (TM) 3800 thermo-mechanical simulator, with varying strain rates of 0.1, 0.5 and 1 s(-1), at different temperatures of 950, 1000, 1050 and 1100 degrees C. The material was homogenized at 1200 degrees C and cooled to deformation temperature prior to hot compression. Dynamic recrystallisation (DRX) parameters were estimated from the observed flow behaviour. Based on the analysis, a correlation was obtained that described the DRX behaviour of the studied steel. The apparent activation energy (Q(def)) for DRX was determined as 480 kJ/mol. This value was considerably higher than that for plain C-Mn steel and gave a favourable DRX condition for grain refinement in linepipe steels

Effect of Strain-Induced Precipitation on the Austenite Non-recrystallization (T-nr) Behavior of a High Niobium Microalloyed Steel

The non-recrystallization temperature (T-nr) of high niobium microalloyed steel was determined from both multihit and double-hit compression tests obtained under plane strain condition. The T-nr was determined to be in the range of 985 degrees C to 1010 degrees C for multihit conditions. The double-hit tests carried out at an interpass time of 5 seconds gave very low T-nr in the range of 860 degrees C to 900 degrees C. In order to understand this, double-hit experiments were carried out for different interpass times (2, 15, 100 seconds) at three different temperatures (950 degrees C, 1050 degrees C, and 1150 degrees C). The negative softening behavior was observed at 950 degrees C for higher interpass times of 15 and 100 seconds. This implies that the T-nr of this steel is well above 950 degrees C. This was due to the high amount of strain-induced precipitation of niobium carbonitrides at higher interpass times as revealed from TEM investigation. The precipitate size evolution considering the Dutta and Sellars nucleation condition in TC-PRISMA agrees well with the experimentally observed precipitate sizes. However, the evolution of Zener pinning forces considering TC-PRISMA nucleation condition is similar to both reported and experimentally determined values. The evolution of tensile properties also correlates well with the observed austenite recrystallization softening behavior. Therefore, a minimum interpass time of 15 seconds is required during double-hit compression tests to effectively precipitate Nb(C, N) and delay the static recrystallization softening behavior of this steel. This lead to the determination of comparable T-nr values between double-hit and multihit methods

Conceptualizing the relative openness of supply chain and its impact on organizational performance

Purpose – The purpose of this paper is to develop a framework conceptualizing the relative openness of a supply chain and its impact on organizational performance. Design/methodology/approach – The literature o

Parametric investigation of coconut shells as partial replacement of coarse aggregates in sustainable concrete

Sustainable construction materials for resource efficiency and environmental effect have grown in popularity .Coconut shells, a waste product of the coconut industry, are plentiful in tropical climates. They are lightweight and permeable, making them an attractive alternative to coarse aggregates. Coconut shells can reduce trash disposal and gravel and sand use by adding them to concrete mixtures. Coconut shell aggregates improve concrete’s mechanical strength and durability, although at a lesser rate than conventional aggregates. Coconut shell replacement depends on particle size, surface properties, and curing conditions. Coconut shells with concrete improve thermal insulation, density, and acoustics. In this investigation compressive and flexural strengths of Grade M20 has been studied by replacing natural coarse aggregates with coconut shells at 0%, 10%, 20% and 30% by weight at curing intervals of 7,14 and 28 days. Cubes and beams were casted and then tested and the tests revealed that coconut shells can be used upto 10% in replacement of natural aggregates imparting a strength almost equivalent to conventional concrete

Artificial Auricular Cartilage Using Silk Fibroin and Polyvinyl Alcohol Hydrogel

Several methods for auricular cartilage engineering use tissue engineering techniques. However, an ideal method for engineering auricular cartilage has not been reported. To address this issue, we developed a strategy to engineer auricular cartilage using silk fibroin (SF) and polyvinyl alcohol (PVA) hydrogel. We constructed different hydrogels with various ratios of SF and PVA by using salt leaching, silicone mold casting, and freeze-thawing methods. We characterized each of the hydrogels in terms of the swelling ratio, tensile strength, pore size, thermal properties, morphologies, and chemical properties. Based on the cell viability results, we found a blended hydrogel composed of 50% PVA and 50% SF (P50/S50) to be the best hydrogel among the fabricated hydrogels. An intact 3D ear-shaped auricular cartilage formed six weeks after the subcutaneous implantation of a chondrocyte-seeded 3D ear-shaped P50/S50 hydrogel in rats. We observed mature cartilage with a typical lacunar structure both in vitro and in vivo via histological analysis. This study may have potential applications in auricular tissue engineering with a human ear-shaped hydrogel