Mechanical properties and thermomechanical behaviour of poly (ethylene-co-vinyl acetate) based shape memory polymer composites

Shape memory polymers (SMPs) are an emerging class of intelligent material that can program in to a temporary shape and recover to its original by exposing to a particular external stimulus. Poly (ethyleneco-vinyl acetate) (EVA) is one of the commercial polymers, which has been used to produce SMPs activated by heat. However, its low mechanical properties, low recovery stress and flexible behaviour restrict the potential applications under robust conditions. Herein, we developed a series of EVA based shape memory polymer composites (SMPCs) with glass fibre, carbon fibre and multi-walled carbon nanotube reinforcements. The effects of different reinforcements on tensile strength have been investigated. Moreover, the dynamic mechanical analysis has been carried out to characterize the glass transition temperature. The shape memory performance of the neat SMP and SMPCs were examined by measuring the angle recovery of 90° bended strips. Subsequently, the shape fixity and recovery ratios of the samples were calculated. This paper presents the manufacturing methods and performance of the fibre and particle reinforced EVA based SMPCs. The inclusion of reinforcements have enhanced the applicability of EVA based SMPCs in wider range of engineering application. In this paper the applicability of such SMPCs for machine elements are deliberated. Accordingly, a conceptual design of a SMPC made mechanical coupler is presented

A Cultural Feminism Analysis of Modern Sinhala Poetry of Female Poets Revealed on the Female Cultural Oppression: Resourcing from Poetry of Anuradha Nilmini, Suharshani Dharmarathna and Vipuli Hettiarachchi

Feminism is an expression of female agony and exhibiting their oppression. In modern poets too, female poets exhibit the expression of female agony through their creations. Those female poets try to express the oppression they experienced and all the females as whole through female ideologies. The main focus of this study is the modern female poets are being culturally oppressed. The difference of femininity is inherited from naturally and the gender has been created by the patriarchal culture. Religion, Customs, Marriage, Morals, the system of ownership, Industries are the incidental elements that subjected to suffer culturally according to the female poets represent through radical poetries. According to the modern female poets that are expressed through their creations, females are suffered physically and mentally than ideology suffering. This research studies how the females are suffered from culturally by selected poetries written on modern poets Anuradha Nilmini, Suharshani Dharmarathna and Vipuli Hettiarachchi. This study is qualitative and selected primary recourses as poets of Anuradha Nilmini, Suharshani Dharmarathna and Vipuli Hettiarachchi. And, as secondary resources this research uses literal articles and books that are written under the feminism, culture and female cultural oppression by modern female poets.DOI: http://doi.org/10.31357/fhss/vjhss.v05i01.0

Investigation of the agricultural resources in Sri Lanka

The author has identified the following significant results. Several in-house capabilities were developed. The facilities to prepare color composites of excellent quality were developed, using bulk B/W 70 mm transparencies or 1:1,000,000 positive transparencies. These color composites were studied through optical devices on light tables. A zoom transfer scope was also added, enabling direct transfer of LANDSAT composite data on to base maps

A Dynamic Shift Share Analysis of Economic Growth in West Virginia

A regional economy consists of industries with a variety of economic potentials. A growth or decline in any of these sectors affects the overall growth of the economy. Analysis of economic growth by sector of a particular region helps policy makers, community leaders and researchers in better decision making and problem solving. This study attempts to analyze the employment growth pattern and policy implications in the economic development of West Virginia using a dynamic shift share analysis. The study uses employment data for 38 years from 1970 to 2007 for the empirical analysis. Results indicate that agriculture, mining and manufacturing are no longer the backbone of the economy of West Virginia. The three sectors showed employment declined within the 38-year period. Service and financial insurance and real estate are the most robust sectors contributing 91 percent of employment growth from 1970 to 2007. Apart from these two sectors, the wholesale and retail and construction sectors showed positive economic growth. Identification of investment priorities within these potential sectors and implementation of a comprehensive regional development policy plan would definitely accelerate the economic growth of West Virginia

The Effect of Diabetes Medication on Cognitive Function: Evidence from the PATH Through Life Study

Objective. To examine the effect of diabetes treatment on change of measures of specific cognitive domains over 4 years. Research Design and Methods. The sample was drawn from a population-based cohort study in Australia (the PATH Through Life Study) and comprised 1814 individuals aged 65-69 years at first measurement, of whom 211 were diagnosed with diabetes. Cognitive function was measured using 10 neuropsychological tests. The effect of type of diabetes treatment (diet, oral hypoglycemic agents, and insulin) on measures of specific cognitive domains was assessed using Generalized Linear Models adjusted for age, sex, education, smoking, physical activity level, BMI, and hypertension. Results. Comparison of cognitive function between diabetes treatment groups showed no significant effect of type of pharmacological treatment on cognitive function compared to diet only group or no diabetes group. Of those on oral hypoglycaemic treatment only, participants who used metformin alone had better cognitive function at baseline for the domains of verbal learning, working memory, and executive function compared to participants on other forms of diabetic treatment. Conclusion. This study did not observe significant effect from type of pharmacological treatment for diabetes on cognitive function except that participants who only used metformin showed significant protective effect from metformin on domain of verbal learning, working memory, and executive function.The PATH Through Life Study was funded by National Health and Medical Research Council (NHMRC) Grants (973302, 179805, and 350833). Kaarin J. Anstey and Nicolas Cherbuin were supported by NHMRC Fellowships (002560 and 1063907, resp.). Pushpani M. Herath was supported by Australian National University International Student Scholarship and Australian Research Council Centre for Excellence in Population Ageing Research (CEPAR)

Biochemical expression of exudes of a fungal-bacterial bio film during growth and maturation

Biofilms are often complex communities of multiple microbial species and remain attached to surfaces. Fungal-bacterial biofllms are formed when the fungal surface is colonized by one or more species of bacteria. These biofilms can enhance microbial effectiveness compared to the monocultures. Beneficial biofilms can be developed in vitro and be used for various agricultural and biotechnological purposes. As a recent development in biofertilizer research, fungal-rhizobial biofilms have been developed and these are termed biofilmed biofertilizers (BFBFs). This research was focused to investigate chemical composition of compounds exuded during growth and maturation of the biofilms. A developed fungal-bacterial biofilm using an Azotobacter species and a Colletorichum fungal species was used for the study. Exudates of the biofilm, fungal monoculture and bacterial monoculture in solid and liquid states were extracted separately by using three organic solvents; hexane, ethyl acetate and methanol. Extraction was done weekly for four weeks during growth and maturation of the biofllm. Then extracted exudates dissolved in organic solvents were evaporated by using a vortex evaporator. Thereafter crude was mixed with potassium bromide (KBr) and pellets were made. The KBr pellets were analyzed using Fourier Transform Infrared (FTIR) spectroscopy. To evaluate the effect of the exudates of the fungal-bacterial biofilm on seed germination and plant growth in comparison to bacterial and fungal monocultures, a plant assay was done weekly by using lettuce (Lactuca sativa) seeds (N 48). During all four harvests, the fungal-bacterial biofllm produced more diverse functional groups than the mono cultures. The developed biofilm produced carboxylic acids and carboxylic salts, which are associated with plant growth promoting hormones, especially in first and second harvests. Significantly higher plant height and high germination of lettuce with the biofilm exudates could be attributed to above fact. During third and fourth weeks, the biofllm produced more amines and amides than fungal and bacterial mono cultures. This may have contributed to increased pH in biofilm cultures compared to the mono cultures. Thus, it can be concluded that biochemical expression of exudates of fungal-bacterial biofilms during their growth and maturation is very useful for breaking dormancy of seeds and their germination and growth, contributing to high plant productivit

Carbon fibre reinforced shape memory polymer composites for deployable space habitats

Intelligent material shape memory polymers (SMPs) and their composites are capable of memorizing and recovering the original shape upon exposure to a particular external stimulus. This paper presents the mechanical properties, thermomechanical behaviour and the shape memory characteristics of 0/90 woven carbon fibre reinforced shape memory composite. The results revealed that the superlative mechanical properties of carbon fibres as a reinforcement has enhanced the strength of the SMP composite (SMPC) to be applicable for space engineering innovations. Furthermore, the recovery behaviour of 90º bended SMPC specimens have been investigated by exposing to heated air and near infraredradiation. Both stimulus methods have shown almost 98% shape recovery. In addition, a model of a cubic deployable structure has been fabricated and respective shape programming and recovery behaviours have been investigated based on the enclosed volume. Interestingly, the deployable structure has been programmed in to almost three times smaller volume and very nearly recovered to its original shape under vacuumed conditions. Accordingly, the carbon fibre reinforced SMPCs can be used to produce deployable space habitats to fabricate on earth, compress and pack in a spacecraft, transport to an outer space location and ultimately deploy in to the original shape