The Kato square root problem on vector bundles with generalised bounded geometry

We consider smooth, complete Riemannian manifolds which are exponentially locally doubling. Under a uniform Ricci curvature bound and a uniform lower bound on injectivity radius, we prove a Kato square root estimate for certain coercive operators over the bundle of finite rank tensors. These results are obtained as a special case of similar estimates on smooth vector bundles satisfying a criterion which we call generalised bounded geometry. We prove this by establishing quadratic estimates for perturbations of Dirac type operators on such bundles under an appropriate set of assumptions.Comment: Slight technical modification of the notion of "GBG constant section" on page 7, and a few technical modifications to Proposition 8.4, 8.6, 8.

A normalisation procedure for biaxial bias extension tests

Biaxial Bias Extension tests have been performed on a plain-weave carbon fibre engineering fabric. The test results have been normalised using both the upper and lower bound method proposed by Potluri et al. and also using a novel alternative normalisation method based on energy arguments. The normalised results from both methods are compared and discussed

Pulse crop impact on soil quality attributes in wheat-based crop rotations

Non-Peer Reviewe

Household water security through stored rainwater and consumer acceptability: a case study of the Anuradhapura District

Rainwater harvesting has increased in popularity in Sri Lanka over the past two decades due to the number of water supply projects funded by the government and non-governmental organizations (NGOs). The stored rainwater can provide accessible, reliable, timely and adequate supplies of water to households but there are uncertainties as to safety, in terms of water quality, and consumer acceptability. A study was, therefore, conducted in the Anuradhapura District, in the dry zone, to assess consumer acceptability of stored rainwater for household purposes and to conduct rainwater quality tests in a laboratory. The majority of households in Anuradhapura meet their drinking water requirements from protected wells (59.6 %). Prior to the project, people greatly preferred open wells as a source of domestic water, followed by tubewells, because they believed that water in open wells is of good quality and drinkable. However, stored rainwater has become the priority source now, especially through roof rainwater harvesting (RRWH), which is used during the dry periods. The study revealed that more than 85 % of households use stored rainwater for drinking although some have concerns over the quality and only drink it after boiling. The easy accessibility of water and the assurance by the project team that it is of good quality are the main reasons that people are willing to drink it. The acceptability of stored rainwater for consumption was very high in water-scarce areas and with the increasing distance to the nearest and alternative sources of good-quality water. Of those who felt that they had adequate water, 84 % of the sample households found it adequate in the wet season but only 21 % in the dry season. Water quality analysis revealed that the chemical and physical quality of stored rainwater is within the acceptable range with respect to Sri Lankan Standards, SLS: 614, for potable water quality (SLIS 1983). Other domestic water sources exceeded standards for electrical conductivity, total alkalinity, hardness, ammonium nitrogen, fluorides and total iron. However, stored rainwater was of lower biological quality than other domestic water sources.Length: pp.87-97Domestic waterWater securityWater harvestingWater qualityRural areasCase studies

Generation gap, gender and shopping enjoyment of shopping mall visitors in western province Sri Lanka

Purpose: Going shopping is a major source of relaxation as well as a daily household chore. However, shopping enjoyment is a burgeoning and rather novel concept, and thus, there is a lack of studies within the cohort, especially with regard to the comparison of the shopping experiences of different generations. This paper explores the nature of shopping enjoyment and measures the impact of the generation gap and gender on visitors’ shopping enjoyment in shopping malls, which records a thriving interest. Design/methodology/approach: In a qualitative survey deploying a convenience sample, 379 usable responses were collected through a self-administered questionnaire from shopping mall visitors in the Western Province of Sri Lanka. Data were analyzed using SPSS (21.0). Findings: Findings of the study indicated that all four generations considered the atmosphere and the environment to be the most important dimensions. Empirical evidence further suggested that Generation Z and Y have the highest enjoyment in their shopping journey within malls compared to other generations, confirming that youth shoppers are the emerging target group for such businesses. Interestingly, it evidenced that shopping is not remaining as a gendered activity anymore, since it is pleasurable for both females and males. Originality: This paper makes a significant contribution to the field by studying shopping enjoyment as a multi-dimensional construct in relation to four generations while being the first such attempt at studying this phenomenon. Implications: Findings are useful for retailers to identify target customers and lucrative markets. Further, shopping malls are required to design to provide more experiences and engagements to customers as a space for pleasure, enjoyment, and entertainment. &nbsp

Heat transfer enhancement in microchannels with liquid-liquid slug flow

The use of microchannels for fluid conduits has significant advantages in a variety of applications. Some of these applications include heat exchangers, micro-reactors, lab-on-a-chip, micro-electronics cooling, and micro-electro-mechanical systems (MEMS). Two-phase flow without phase change can radically increase the heat and mass transfer rates in microchannels due to the internal recirculation of the fluids. These two-phase flows are either made up of gas–liquid or immiscible liquid–liquid slug flows. Liquid-liquid slug flow has gained more attention recently due to the better thermal properties of liquids compared to gases. While there have been extensive studies on gas-liquid slug flow, there is little information available on liquid-liquid slug flow, particularly during heat transfer. Thus, this research presents the hydrodynamics and thermal characteristics of liquid-liquid slug flows in micro/mini channels.The research project involves both experimental and numerical investigations and the study is categorised into three main components; namely slug flow formation and visualization, pressure drop measurements and heat transfer studies. Both experimental and numerical studies showed a significant increase of heat transfer rates in liquid-liquid slug flow compared to it single phase counterpart. The modelling and experiments were carried out for a wide range of flow parameters, and the effect of those parameters on heat transfer is presented

Retention of essential fatty acids in fish differs by species, habitat use and nutritional quality of prey

Algae-produced long-chain polyunsaturated fatty acids (LC-PUFA; with >= 20 carbon atoms) are key biomolecules for consumer production and animal health. They are transferred to higher trophic levels and accumulated in food chains. However, LC-PUFA accumulation in consumers and their trophic transfer vary with the diet quality and the physiological demand for LC-PUFA of consumers. The goal of this study was to investigate spatial and taxonomic differences in LC-PUFA retention of coastal fish predators that potentially differ in their habitat use (benthic versus pelagic) and prey quality. We analyzed the fatty acid (FA) composition of common fish species, namely roach and European perch, as well as their potential prey from benthic and pelagic habitats in three bays of the northern Baltic Sea. We then assessed whether the fish LC-PUFA retention differed between species and among the study bays with different diet quality, that is, LC-PUFA availability. Our data indicated taxon-specific differences in the retention of LC-PUFA and their precursor FA in fish (i.e., short-chain PUFA with <20 carbon atoms). Perch did not show any spatial variation in the retention of all these FA, while roach showed spatial differences in the retention of docosahexaenoic acid (DHA) and their precursor FA, but not eicosapentaenoic acid (EPA). Data suggest that diet quality and trophic reliance on benthic prey underlay the DHA retention differences in roach. Although the PUFA supply might differ among sites, the low spatial variation in LC-PUFA content of perch and roach indicates that both fishes were able to selectively retain dietary LC-PUFA. Climate change together with other existing human-caused environmental stressors are expected to alter the algal assemblages and lower their LC-PUFA supply for aquatic food webs. Our findings imply that these stressors will pose heterogeneous impacts on different fish predators. We advocate further investigations on how environmental changes would affect the nutritional quality of the basal trophic level, and their subsequent impacts on LC-PUFA retention, trophic ecology, and performance of individual fish species

Effects of recreational camping on the environmental values of national parks in Sri Lanka

Camping is a popular activity in the contemporary nature-based tourism domain and rapidly gaining momentum as a key recreational activity in Sri Lanka’s national parks (NPs). Recreational uses such as camping in natural areas can induce significant and often localised resource impacts that can affect soil, vegetation, wildlife and water, with the severity of such impacts varying according to the intensity of use. Hence, monitoring of the biophysical conditions of campsites has become an important component in the reserve management agenda in many places, especially in developed countries. To the best of our knowledge, this is the first study to examine the biophysical impacts associated with the recreation ecology of camping in Sri Lanka. Ten campsites from three dry zone NPs were selected to assess biophysical impacts of camping activities. Field measurements were based on the fixed radial transect method. Gathered data included the total area of the campsite, erosion potential measured as the area of exposed soil (devoid of vegetation or organic litter), number of exposed roots and human damage to trees, number of fireplaces/ fire scars on the ground, visual counts of litter, soil compaction measured by penetrometer, loss of woody debris. This study reports significant levels of environmental degradation related to all the indictors of biophysical impacts at both high and low use campsites. There was no evidence for any difference in the level of environmental degradation associated with high and low use campsites. The loss of natural values associated with campsites negatively impacted visitors’ nature-based experience. These findings highlight the importance of managing biophysical impacts in campsites to provide a high-quality visitor experience, while sustainably managing tourism activities in NPs