Turbulent Friction Drag Reduction Using Electroactive Polymer Surfaces

Both experiments and numerical simulations have provided evidence that an initially fully developed two-dimensional boundary layer, subjected to a sudden spanwise forcing, exhibits a decrease of turbulent quantities such as the Reynolds shear stress, turbulent kinetic energy and turbulent friction drag. In past experiments and investigations, such forcing has traditionally been in the form of spanwise wall oscillations, spanwise travelling Lorentz forcing, superimposed spanwise pressure gradients and spanwise travelling waves of an inplane flexible wall. The aim of this work is to take the idea a step further and develop an active surface which locally executes the motions described above making such a system more readily deployable. Two surfaces were developed: both executing in-plane local oscillations with amplitude close to or larger than the mean streak spacing in a turbulent flow, but based on two different technologies, electroactive polymers in the dielectric form of actuation and electromagnetic motor forcing. The effect of these two surfaces was confined to wall-normal heights on the order of the linear sublayer of the turbulent boundary layer, and frequency and wavelength similar to those reported in literature. Extensive hot-wire measurements, some PIV measurements and direct measurement of friction drag using a bespoke drag balance are presented for the systematic variation of the relevant parameters for turbulent friction drag reduction. Electroactive polymers (EAP) are able to undergo relatively large deflections at high frequencies. Developments in the field of EAP such as static and dynamic characterisation of the EAP membranes in use in this work, development of robust electrodes and their characterisation, in-house manufacturing of thin silicone membranes and post-processing of pre-built silicone membranes are presented. Numerical studies of the optimum pre-strain values and of the optimum electrode to passive portions width ratios are presented. Actuator development techniques including EAP membrane pre-stretch in a bespoke jig, EAP membrane pre-conditioning to go past the Mullins' effect, electrode preparation procedure and deposition, and frame preparation are presented. Actuator characterisation results including analysis of multi-flash photographs and laser profilometer scans for in-plane and out-plane deflections at different frequencies are also presented

Addressing the need for an adult allergy clinic in Malta

The incidence of allergy is globally on the increase. Allergology is a relatively new speciality with rapidly growing needs. Many patients have co-existent allergic conditions including asthma, eczema, allergic rhinitis, food and drug allergy. It is recommended internationally that patients suffering from allergic conditions including anaphylaxis are investigated, treated and followed up by an allergy specialist in a safe environment with resuscitation facilitations readily available, especially when certain investigations are performed. This article highlights the importance of the need for such an allergy service for adult patients at Mater Dei Hospital, in patients with new onset or previously undiagnosed allergic conditions as well as transition of care from paediatric services, with the intention of performing specialist investigations, providing optimal expert management and expert to allergy sufferers locally whilst improving patients’ quality of life. A multidisciplinary team approach would further improve this service.peer-reviewe

Interstitial lung disease in Malta

Aim: To establish the prevalence, management and response to treatment of interstitial lung disease (ILD) in Malta. Methodology: The personal files of 102 living and 26 deceased patients with ILD under the care of 4 respiratory physicians were reviewed retrospectively. The investigations utilised for reaching the diagnosis, patient management and response to treatment were analysed. Results: The prevalence of ILD was estimated at 24.9 per 100,000 population. Pulmonary function tests were performed at least once in 109 patients (n=128, 85%), and pletysmography and exercise oximetry in 36 patients (n=128, 28%). A chest x-ray (CXR) was performed in 120 patients (n=128, 93.7%), of which 8 (n=120, 6.66%) were normal, a computed tomography scan of the thorax in 113 patients (n=128, 88.3%), all of which showed fibrotic changes and a DTPA scan in 17 patients (n=128, 13.3%). Regarding more invasive investigations, bronchoalveolar lavage was performed in 10 patients (n=128, 7.8%), open lung biopsy in 4 patients (n=128, 3.1 %), video-assisted thoracoscopic surgery in 4 patients (n=128, 3.1%) and transbronchial lung biopsy in 7 patients (n=128, 5.5%). Corticosteroids were the most common drugs prescribed in 64 patients (n=128, 50%) followed by azathioprine in 23 patients (n=128, 18%) and cyclophosphamide in 3 patients (n=128, 2.3%). There was a definite worsening in lung function associated with increasing age. There was no standardisation of follow up for these patients. Conclusion: The method of diagnosis, management and follow up of patients with ILD locally requires improvement to optimise standards of care and hence compare with proposed international guidelines.peer-reviewe

Pregnancy and asthma

Asthma is the most common chronic condition encountered in pregnancy. Due to lack of evidence on the adverse effects of asthma medication during pregnancy, there is persistent concern regarding use of asthma-related medication throughout the pregnancy, management of exacerbations and asthma management during labour. Several respiratory-related physiological changes are said to occur during pregnancy which could possibly worsen or improve asthma, and asthma as well as its treatment can affect pregnancy outcomes. The aim of this paper is to summarize current literature findings on clinical management issues encountered in this cohort of patients.peer-reviewe

Chronic lung disease in adults and air travel

The safety of travelling in patients suffering from chronic lung conditions is a frequently encountered problem amongst healthcare professionals. The objective of this paper is to review currently available literature, with the aim of clarifying such issues for doctors dealing with such concerns. The article will describe the effect of altitude on healthy and diseased lungs, assessment tools to be utilised when assessing patients with suspected or diagnosed chronic lung conditions and international guideline recommendations for chronic lung conditions.peer-reviewe

Bacterial conjunctivitis

Bacterial conjunctivitis is a very common ophthalmic condition that can affect anyone from day one of life to old age. It is one of the commonest reasons for self-referrals of patients visiting eye specialists. It is defined ad an inflammation of the conjunctiva by bacteria where the palpebral, bulbar and forniceal parts of the conjunctiva become hyperaemic. The infection can be acute, hyperacute or chronic. Contrary to popular belief it can be self-limiting but it is frequently treated with broad-spectrum antibiotics most commonly in drop form. Very rarely it can progress to complications such as keratitis (corneal infection) or pre-septal cellulitis (skin infection of the lids)peer-reviewe

The role of prostanoids in the modern management of glaucoma

The history of glaucoma pharmacology begins in 1862 with the isolation of physostigmine from the calabar bean. The discovery of epinephrine’s intraocular pressure lowering capacity came just after WWI. During the 20th century, drug discovery and development accelerated, with the introduction of carbonic anhydrase inhibitors, beta-blockers (1970s), alpha-agonists and lately prostanoids(1990s).2 Prostanoids have been divided into PG analogues and prostamides because of differences in molecular structures. The drugs share a novel mechanism of action that produces a potent ocular hypotensive effect and a novel local adverse effect of increased iridial pigmentation. Anti-glaucoma medication targets different key pathophysiological aspects of the disease and overlap in the mechanisms of action of these drugs proved to be important. The development of a completely new class of drugs added to the suppressive armamentarium against this blinding condition. More drug variety skewed glaucoma care away from the theatre, effectively changing the timing of glaucoma surgery.peer-reviewe

Mycoplasma pneumonia : an unusual cause of acute myocarditis in childhood

Mycoplasma pneumoniae is primarily a respiratory pathogen but may affect exhibit a diverse range of presentations from asymptomatic infection to life threatening conditions. Myocarditis of varying severity is an unusual complication. We report a 6 year old with mycoplasma myocarditis, a rare age for such a presentation, and who responded well to treatment with no sequelae. Serological testing for Mycoplasma pneumoniae should be part of the routine work-up for myocarditis.peer-reviewe

Photoelectron spectroscopy of NpPd3 and PuPd3

We present the results of x-ray and ultraviolet photoelectron spectroscopy of NpPd3 and PuPd3. The spectra indicate that for both compounds, the 5f electrons are well localized on the actinide sites. Comparison with bulk measurements indicates that for NpPd3 the electrons have a valence of Np3+ and thus a ground state 5f4 with a Hund's rules 5I4 configuration. Similarly for PuPd3, we find a Pu3+ valence, 5f5 ground state and a Hund's rules 6H5/2 configuration