Investigation of steady incompressible flows in the vicinity of an airfoil

O-type body-fitted coordinate systems are numerically generated about NACA0012 and NACA4412 airfoils. These coordinate systems are used to effect a coordinate transformation from the physical plane to a rectangular transformed plane. The software developed also has a coordinate contraction capability. Plots of uncontracted and contracted coordinate systems are presented. The nonconservative, velocity-pressure formulation of the two-dimensional, steady-state Euler equations are transformed to the rectangular plane. The boundary conditions at the airfoil are determined by the source-panel method, following which, the explicit finite difference form of the transformed Euler equations are solved using a space-marching scheme. Non-lifting potential flow solutions are obtained for the aforementioned airfoils at 0 and ±16 angles of attack. Pressure and velocity distribution plots are presented for all cases

Characterization of the exopolysaccharide produced by a whey utilizing strain of Klebsiella oxytoca

Physical, chemical and rheological properties of a polysaccharide produced by an isolate of Klebsiella oxytoca were characterized. Freeze dried samples of the polysaccharide were neutral and werecompletely soluble in water. Samples did not form gels even in the presence of salt treatments. The major monosaccharide constituents of the polysaccharide were rhamnose (37%, w/w) and glucose(34%, w/w). Residues of cellobiose were detected, suggesting that the polysaccharide had a cellulose backbone. The gum was more comparable to broth apparent viscosities of xanthan gum than to gellangum. The K. oxytoca polysaccharide (KOP) produced high solution viscosity at low concentrations. At a gum concentration 0.5% (w/v), an apparent viscosity of 400 cP at 24 s-1 was obtained. Rheologicalbehavior showed that the KOP formed non newtonian fluids, indicating that it is a pseudoplastic biopolymer. Although the KOP solutions displayed pseudoplastic behavior, increases in shearing timedid not result in significant changes on the apparent viscosity. This indicated that the gum is neither thixotropic nor rheopectic. The conclusion reached about the potential application of the gum was thatit could be suitable for use as a stabilizing or suspending agent rather than a gelling agent

Developing a Culturally Appropriate Measure of Effective Leadership for Sri Lanka

Research has shown that characteristics of effective leadership differ in different national cultures. Measures available for evaluating effective leadership are limited. There are tools developed in South Asian countries such as India. However, research has shown Sri Lankan cultural values differ from these countries. This paper identified behaviours and traits of leadership that are perceived as important for an effective leader in the Sri Lankan context. It also presents a Questionnaire for Evaluation of Effective Leadership (QEEL) to assess effective leadership in Sri Lanka, and explains the development process of this questionnaire. The QEEL covers eight aspects: motivation, guidance, communication, decision-making, empathy, integrity, and change management. It was designed in three steps: Item generation, Item identification and Validation. QEEL can also be used by organisations and researchers in other countries with similar cultural values

Integration of the rational, political and justice models of performance appraisals: The case of the Sri Lankan public sector

In recent times there have been urgent calls for reforms in the public sector, and thereby certain private sector management techniques have been advocated to be implemented in the public sector. Special emphasis has been placed on performance management and thereby performance appraisals in this regard. However, research and observation show that performance appraisals have failed in their duty in both the private sector and the public sector in their design as well as their implementation. Performance appraisals literature speaks of three models, namely, the rational, political and justice models. However, they have been researched in isolation and conclusions drawn..

An identification procedure for woolly soft-flesh peaches by instrumental assessment

Woolliness in peaches, a negative attribute of sensory texture characterized by the lack of crispness and juiciness, also known as mealiness in other fruits, has been identified fruit-by fruit by instrumental means. The use of a non-supervised clustering data analysis procedure, studying crispness and juiciness, enables four instrumental degrees of texture degradation to be defined, of which woolliness appears to be the last stage. This procedure also provides some information on several experimental factors (ripeness stages, storage time and storage temperature) with regard to the onset of woolliness. It is confirmed through this study that, in Maycrest peaches, woolliness starts to appear after 2 weeks of storage at 5°C. Fruits classified at harvest in 'first' and 'second' ripeness stages are more susceptible to woolliness than those in the third ripeness stage. This clustering procedure may also be effective for studying other species, varieties and quality attributes of fruit

Mealiness assessment in apples and peaches using MRI techniques

Mealiness (woolliness in peaches) is a negative attribute of sensory texture that combines the sensation of a desegregated tissue with the sensation of lack of juiciness. In this study, 24 apples cv. Top Red and 8 peaches cv. Maycrest, submitted to 3 and 2 different storage conditions respectively have been tested by mechanical and MRI techniques to assess mealiness. With this study, the results obtained on apples in a previous work have been validated using mathematical features from the histograms of the T2 maps: more skewed and the presence of a tail in mealy apples, similar to internal breakdown. In peaches, MRI techniques can also be used to identify woolly fruits. Not all the changes found in the histograms of woolly peaches are similar from those observed in mealy apples pointing to a different underlying physiological change in both disorder

Biomedical and microbiological applications of bio-based porous materials: a review

Extensive employment of biomaterials in the areas of biomedical and microbiological applications is considered to be of prime importance. As expected, oil based polymer materials were gradually replaced by natural or synthetic biopolymers due to their well-known intrinsic characteristics such as biodegradability, non-toxicity and biocompatibility. Literature on this subject was found to be expanding, especially in the areas of biomedical and microbiological applications. Introduction of porosity into a biomaterial broadens the scope of applications. In addition, increased porosity can have a beneficial effect for the applications which exploit their exceptional ability of loading, retaining and releasing of fluids. Different applications require a unique set of pore characteristics in the biopolymer matrix. Various pore morphologies have different characteristics and contribute different performances to the biopolymer matrix. Fabrication methods for bio-based porous materials more related to the choice of material. By choosing the appropriate combination of fabrication technique and biomaterial employment, one can obtain tunable pore characteristic to fulfill the requirements of desired application. In our previous review, we described the literature related to biopolymers and fabrication techniques of porous materials. This paper we will focus on the biomedical and microbiological applications of bio-based porous materials

Physiological protection of probiotic microcapsules by coatings

Nowadays, food and nutrition have a greater impact in people's concerns, with the awareness that nutrition have a direct impact in health and wellbeing. Probiotics have an important role in this topic and consumers are starting to really understand their potential in health, leading to an increasing interest of the companies to their commercial use in foods. However, there are several limitations to the use of probiotics in foods and beverages, being one of them their efficiency (directly associated to their survival rate) upon ingestion. This work is focused in microencapsulation techniques that have been used to increase probiotics efficiency. More specifically, this work reviews the most recent and relevant research about the production and coating techniques of probiotic-loaded microcapsules, providing an insight in the effect of these coatings in probiotics survival during the gastrointestinal phase. This review shows that coatings with the better performances in probiotics protection, against the harsh conditions of digestion, are chitosan, alginate, poly-L-lysine and whey protein. Chitosan presented an interesting performance in probiotics protection being able to maintain the initial concentration of viable probiotics during a digestive test. The analyses of different works also showed that the utilization of several coatings does not guarantee a better protection in comparison with monocoated microcapsules.The author Philippe E. Ramos is recipient of fellowships from the Fundação para a Ciência e Tecnologia, POPH-QREN and FSE (FCT, Portugal) through the grant SFRH/BD/80800/2012. This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684). RECI Project (Until December of 2017): This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the Project RECI/BBBEBI/0179/2012 (FCOMP-01-0124-FEDER-027462).info:eu-repo/semantics/publishedVersio

Squamous cell carcinoma of the ampulla of vater – A case report

Introduction: Ampullary carcinoma comprises up to 2% of all gastrointestinal malignancies. Primary squamous cell carcinoma of the ampulla is a very rare neoplasm, with only three reported cases in literature. Due to its rarity, the biological behavior is largely unknown. We highlight such a case, and its diagnostic workup.Case Report: A 61 year old woman presented with painless obstructive jaundice of 2 months duration. MRI scan showed a stricture in the distal common bile duct suggestive of a neoplasm. Biopsy at ERCP showed a poorly differentiated ampullary carcinoma. The specimen received at Whipple’s surgery showed a white tumour surrounding the ampulla, 25 mm in maximum dimension. Histology and immunohistochemistry (CK 7+/20 -, CA 19-9+, CK5/6 focally+) pointed towards a poorly differentiated squamous cell carcinoma. A primary squamous carcinoma elsewhere was excluded. The patient is alive nine months after surgery.Discussion: Ampullary squamous cell carcinoma is most often metastatic from sites such as the larynx, esophagus, lung and uterus. A squamous carcinoma therefore requires ruing out of a primary site elsewhere or a glandular component (adenosquamous carcinoma). These were excluded in this patient. Immunohistochemistry differed from that of primary adenocarcinoma of the ampulla