Modelling of microstructural evolution in multi-layered overlay coatings

Functionally graded, multi-layered coatings are designed to provide corrosion protection over a range of operating conditions typically found in industrial gas turbines. A model incorporating diffusion, equilibrium thermodynamics and oxidation has been developed to simulate the microstructural evolution within a multi-layered coating system. The phase and concentration profiles predicted by the model have been compared with an experimental multi-layered system containing an Al-rich outer layer, a Cr-enriched middle layer and an MCrAlY-type inner layer deposited on a superalloy substrate. The concentration distribution and many microstructural features observed experimentally can be predicted by the model. The model is expected to be useful for assessing the microstructural evolution of multilayer coated systems which can be potentially used on industrial gas turbine aerofoils

Olax zeylanica: AN ENVIRONMENTALLY SAFE BIO-PESTICIDE FOR THE CONTROLOF THE MAIZE WEEVIL SITOPHILUS ZEAMAIS MOTS. (CURCULIONIDAE)

Leaf powders of Ocimum graticimum, Morinda citrifolia, Aegle marmelos, Annona squamosa, Annonareticulata, Olax zeylanica and Ricinus communis were screened for their insecticidal activity underlaboratory conditions (30±1 ºC and 84 - 86% RH) against Sitophilus zeamais. The powders at the rate of15g/50g of maize grains were tested and adult mortality was recorded after 24 hours. O. zeylanica washighly effective against S. zeamais eliciting 100% mortality. Mortality for other six plants was significantlylower ranging from 5.28 to 21.24%. O. zeylanica was tested at five dose rates (1.0, 2.5, 5.0, 7.5, 10.0g) andmortality of adult weevils was recorded after 6, 12 and 24 hours. Mortality of weevils increased with theincrease of the dose as well as the exposure time. Also, weevil mortality was 100% at the dose of 10g justafter 12 hours. Results of this study indicated that leaf powder of O. zeylanica was extremely toxic to S.zeamaize weevils. LD50 and LD99 values after 6,12and 24 hours of exposure were 5.84, 2.47, 1.84g and38.55, 8.33 and 6.51g respectively. The present study revealed that Olax zeylanica has high potential as abio-pesticide which can compete effectively with hazardous insecticides in managing S. zeamaisinfestations.Keywords: Olax zeylanica, Sitophilus zeamais, Insecticidal activit

Modelling the coefficient of thermal expansion in Ni-based superalloys and bond coatings

The coefficient of thermal expansion (CTE) of nickel-based superalloys and bond coat layers was modelled by considering contributions from their constituent phases. The equilibrium phase composition of the examined materials was determined using thermodynamic equilibrium software with an appropriate database for Ni-based alloys, whereas the CTE and elastic properties of the principal phases were modelled using published data. The CTEs of individual phases were combined using a number of approaches to determine the CTE of the phase aggregate. As part of this work, the expansion coefficients of the superalloy IN-738LC and bond coat Amdry-995 were measured as a function of temperature and compared with the model predictions. The predicted values were also validated with the published data for the single-crystal superalloy CMSX-4 and a number of other Ni-based alloy compositions at 1000 K. A very good agreement between experiment and model output was found, especially up to 800  $$^\circ$$ � C. The modelling approaches discussed in this paper have the potential to be an extremely useful tool for the industry and for the designers of new coating systems

Computer literacy & attitudes towards e-learning among Sri Lankan Medical Students.

E-learning which is gaining popularity among medical faculties in Sri Lanka requires access to computers and considerable knowledge on information technology. The aim of this study was to assess the computer literacy andattitudes towards e-learning among second year medical students of the Faculty of Medicine, Colombo (n=138)using a self administered, anonymous questionnaire.Results showed that 93.5% of students owned a computer and 95% of them had internet connection. Use ofMicrosoft Office® applications was high (90%), along with online communication tools (73.5%). Using ICT foreducational purposes was low (51.7%). Use of popular Web 2.0 tools such as Facebook (89.1%), Wikipedia(87.6%), and YouTube (74.4%) was high. There was a significant difference between gender in the use of blogs(P<0.01), and Twitter (P<0.01) with male students using these more. Majority of students (65.7%) spent less time ontheir computer for learning purposes.Commonly accessed online learning materials were text (82.3%) and images (81.7%). Advantages of online learningmaterials have been recorded as being more accessible (89.5%), descriptive (85.7%) and easily searchable (88.1%).Awareness of the faculty Moodle platform was low among students (65.7%), as well as usage (32.7%) and 94.7% ofstudents preferred supplementary learning material to be incorporated in the Moodle platform. This study shows that medical students have access to computers and other facilities required for e-learning and apositive attitude towards e-learning. However, the use of computers for learning purposes was low. This highlightsthe need for guidance on the use of available resources for e-learning

Eco-Friendly Alternatives for Storage Pest Management:Leaves of Ruta Graveolens (Aruda) as a Repellent Against the Rice Weevil, Sitophilus Oryzae L.

In view of worldwide interest and greater public awareness in finding plant products as the most promising and ecologically safer alternatives for synthetic insecticides in post-harvest protection of stored rice, present study was undertaken to explore the potential of leaves of Ruta graveolens (Aruda) as a repellent against S.oryzae infestations. Leaf powder and solvent extracts of R. graveolens were evaluated for their contact and fumigant repellent properties against seven day old S. oryzae adults. In contact repellency test, weevils (20 each) were exposed to 1.0 g, 3.0 g, 5.0 g, and 7.0 g of leaf powder mixed with white raw rice grains in a modified cup bioassay apparatus. Fumigation repellency of leaf powder was tested using same dosages and the number of weevils in a fumigation-repellency chamber. Number of weevils that moved from the bioassay chamber was recorded one hour after weevil introduction. Leaves of R. graveolens were extracted in hexane, ethyl acetate, methanol, distilled water and different concentrations 10, 50, 100% (v/v) were assessed separately to evaluate repellent activity by means of an area preference bioassay. In all experiments, ten weevils for each were tested and the number repelled was recorded 30 minutes after weevil introduction. Highest contact and fumigant repellent effects were elicited by 7.0 g of leaf powder resulting 96% and 95% respectively, whilst lowest dose also produced more than 50% repellency indicating extremely strong repellent action of the plant powder. In comparison, aqueous extract exhibited the most potent repellent activity (91%) while other extracts were producing over 70% repellent effects on weevils at the concentration of 100% (v/v). Overall findings of the study suggest that both powder and extracts of R. graveolens leaves could be used as eco-friendly agents for post-harvest rice protection. KEYWORDS: Ruta graveolens, Sitophilus oryzae, stored rice, leaf powder, repellen

Applications of Computation-In-Memory Architectures based on Memristive Devices

Today's computing architectures and device technologies are unable to meet the increasingly stringent demands on energy and performance posed by emerging applications. Therefore, alternative computing architectures are being explored that leverage novel post-CMOS device technologies. One of these is a Computation-in-Memory architecture based on memristive devices. This paper describes the concept of such an architecture and shows different applications that could significantly benefit from it. For each application, the algorithm, the architecture, the primitive operations, and the potential benefits are presented. The applications cover the domains of data analytics, signal processing, and machine learning

The Secret Life of Collagen: Temporal Changes in Nanoscale Fibrillar Pre-Strain and Molecular Organization during Physiological Loading of Cartilage

Articular cartilage is a natural biomaterial whose structure at the micro- and nanoscale is critical for healthy joint function and where degeneration is associated with widespread disorders such as osteoarthritis. At the nanoscale, cartilage mechanical functionality is dependent on the collagen fibrils and hydrated proteoglycans that form the extracellular matrix. The dynamic response of these ultrastructural building blocks at the nanoscale, however, remains unclear. Here we measure time-resolved changes in collagen fibril strain, using small-angle X-ray diffraction during compression of bovine and human cartilage explants. We demonstrate the existence of a collagen fibril tensile pre-strain, estimated from the D-period at approximately 1–2%, due to osmotic swelling pressure from the proteoglycan. We reveal a rapid reduction and recovery of this pre-strain which occurs during stress relaxation, approximately 60 s after the onset of peak load. Furthermore, we show that this reduction in pre-strain is linked to disordering in the intrafibrillar molecular packing, alongside changes in the axial overlapping of tropocollagen molecules within the fibril. Tissue degradation in the form of selective proteoglycan removal disrupts both the collagen fibril pre-strain and the transient response during stress relaxation. This study bridges a fundamental gap in the knowledge describing time-dependent changes in collagen pre-strain and molecular organization that occur during physiological loading of articular cartilage. The ultrastructural details of this transient response are likely to transform our understanding of the role of collagen fibril nanomechanics in the biomechanics of cartilage and other hydrated soft tissues

Editorial: Crop modelling - underutilized crops for climate-smart agrifood systems

Climate change is posing a significant threat to our food systems they are highly exposed to complex and unpredictable environmental changes and more susceptible to shocks, where climate change serves as a primary cause for the increasing vulnerability of these systems. Building climate-resilient food systems will enable us to deal with these shocks, complexity, and unpredictability, which ultimately contribute to food security and sustainable food systems. The limited range of crops supplying global food requirements makes food systems more vulnerable to climate hazards. Currently, over 50% of consumed calories come from just three staple crops (rice, maize, and wheat), leaving behind the extensive variety of nutrient-rich plants that have been historically utilized by humanity (Hunter et al., 2019)

Pathological Characteristics of Primary Bladder Carcinoma Treated at a Tertiary Care Hospital and Changing Demographics of Bladder Cancer in Sri Lanka

Objectives. The aim was to compare demographics and pathological features of bladder carcinoma treated in a urology unit with findings of previous studies done in Sri Lanka. Materials and Methods. Data of newly diagnosed patients with bladder cancer in a tertiary referral centre from 2011 to 2014 were analysed. Data on bladder cancers diagnosed from 1993 to 2014 were obtained from previous publications and Sri Lanka Cancer Registry. Results. There were 148 patients and mean age was 65 years. Male to female ratio was 4.1 : 1. Urothelial carcinoma (UC) was found in 89.2% of patients. Muscle invasion was noted in 35% of patients compared to 48.4% two decades ago. In patients with UC, 16.5% were found to have pT1 high grade tumour. It was 5.3% from 1993 to 2000. Pure squamous cell carcinoma was found in 8.1% of patients while primary or de novo carcinoma in situ (not associated with high grade pT1 tumours) was seen in one patient only. Conclusions. The percentage of squamous carcinoma is higher among Sri Lankan patients while primary carcinoma in situ is a rarity. The percentage of muscle invasive disease has decreased while the percentage of pT1 high grade tumours has increased during the last two decades in Sri Lanka

Editorial: Crop modelling - underutilized crops for climate-smart agrifood systems

Climate change is posing a significant threat to our food systems they are highly exposed to complex and unpredictable environmental changes and more susceptible to shocks, where climate change serves as a primary cause for the increasing vulnerability of these systems. Building climate-resilient food systems will enable us to deal with these shocks, complexity, and unpredictability, which ultimately contribute to food security and sustainable food systems. The limited range of crops supplying global food requirements makes food systems more vulnerable to climate hazards. Currently, over 50% of consumed calories come from just three staple crops (rice, maize, and wheat), leaving behind the extensive variety of nutrient-rich plants that have been historically utilized by humanity (Hunter et al., 2019)