Investigation of Corrugated Wing in Unsteady Motion

Delayed stall is the most dominant lift enhancing factor in insect flapping motion. Micro air vehicle operates at Reynolds number 104-105; slightly higher than the insects’ Reynolds number (Re). In the present research, thefocus is to investigate “stall-absent” phenomenon at Re representative of the micro air vehicles, the effect of spanwiseflow on the leading edge vortex and also to study the effect of geometry variations on the aerodynamic performance of the wing in unsteady motion. Corrugated dragonfly airfoil with rectangular wing planform is used, however, with wing kinematics restricted to azimuth rotation only. Three-dimensionalfinite-volume method is used, through commercial software Fluent, to numerically solve time-dependent incompressible Navier-Stokes equations. Computed results at Re 34000 and 100,000 reveal the same phenomenon of delayed stall, as observed in the case of insects. Furthermore, the performance of flat plate, profiled and corrugated wing in a sweeping motion at a high angle of attack is also compared

Development of adaptive algorithms for the operation of windows, fans, and doors to predict thermal comfort and energy use in Pakistani buildings

This year-round field investigation of the use of building controls (windows, doors and fans) in 33 Pakistani offices and commercial buildings focuses on 1) how the occupants' behavior is related to thermal comfort, 2) how people modify the indoor environment and 3) how we can predict the occupants' behavior. We have found that the use of building controls depends on climate and season. The use of these controls has a cooling effect on the occupant through increasing the air movement or the ventilation. The behavioral model yields adaptive algorithms that can be applied in building thermal simulations to predict the effects of the occupants' behavior on energy-saving building design

Bi2O3/Nylon multilayered nanocomposite membrane for the photocatalytic inactivation of waterborne pathogens and degradation of mixed organic pollutants

Worldwide there is an increasing demand for clean water and sanitation systems and any different solutions are under evaluation, including advanced oxidation processes such as photocatalysis. This work describes the scalable synthesis process of an electrospun composite membrane made of Nylon and embedded α/β-Bi2O3 nanoparticles that can be activated by visible light instead of UV light typically used with other nanomaterials (e.g. TiO2). As a proof of concept, the efficacy of the α/β-Bi2O3 electrospun composite membrane in the visible light inactivation of pollutants and pathogens was demonstrated in a Continuous-flow Photocatalytic Membrane Reactor, highlighting the great potential of this advanced photocatalytic process for clean water and sanitation

Considering the impact of situation-specific motivations and constraints in the design of naturally ventilated and hybrid buildings

A simple logical model of the interaction between a building and its occupants is presented based on the principle that if free to do so, people will adjust their posture, clothing or available building controls (windows, blinds, doors, fans, and thermostats) with the aim of achieving or restoring comfort and reducing discomfort. These adjustments are related to building design in two ways: first the freedom to adjust depends on the availability and ease-of-use of control options; second the use of controls affects building comfort and energy performance. Hence it is essential that these interactions are considered in the design process. The model captures occupant use of controls in response to thermal stimuli (too warm, too cold etc.) and non-thermal stimuli (e.g. desire for fresh air). The situation-specific motivations and constraints on control use are represented through trigger temperatures at which control actions occur, motivations are included as negative constraints and incorporated into a single constraint value describing the specifics of each situation. The values of constraints are quantified for a range of existing buildings in Europe and Pakistan. The integration of the model within a design flow is proposed and the impact of different levels of constraints demonstrated. It is proposed that to minimise energy use and maximise comfort in naturally ventilated and hybrid buildings the designer should take the following steps: 1. Provide unconstrained low energy adaptive control options where possible, 2. Avoid problems with indoor air quality which provide motivations for excessive ventilation rates, 3. Incorporate situation-specific adaptive behaviour of occupants in design simulations, 4. Analyse the robustness of designs against variations in patterns of use and climate, and 5. Incorporate appropriate comfort standards into the operational building controls (e.g. BEMS)

Signal intensity and volume of carotid intraplaque hemorrhage on magnetic resonance imaging and the risk of ipsilateral cerebrovascular events:The Plaque At RISK (PARISK) study

Background: The Plaque At RISK (PARISK) study demonstrated that patients with a carotid plaque with intraplaque hemorrhage (IPH) have an increased risk of recurrent ipsilateral ischemic cerebrovascular events. It was previously reported that symptomatic carotid plaques with IPH showed higher IPH signal intensity ratios (SIR) and larger IPH volumes than asymptomatic plaques. We explored whether IPH SIR and IPH volume are associated with future ipsilateral ischemic cerebrovascular events beyond the presence of IPH. Methods: Transient ischemic attack and ischemic stroke patients with mild-to-moderate carotid stenosis and an ipsilateral IPH-positive carotid plaque (n = 89) from the PARISK study were included. The clinical endpoint was a new ipsilateral ischemic cerebrovascular event during 5 years of follow-up, while the imaging-based endpoint was a new ipsilateral brain infarct on brain magnetic resonance imaging (MRI) after 2 years (n = 69). Trained observers delineated IPH, a hyperintense region compared to surrounding muscle tissue on hyper T1-weighted magnetic resonance images. The IPH SIR was the maximal signal intensity in the IPH region divided by the mean signal intensity of adjacent muscle tissue. The associations between IPH SIR or volume and the clinical and imaging-based endpoint were investigated using Cox proportional hazard models and logistic regression, respectively. Results: During 5.1 (interquartile range: 3.1–5.6) years of follow-up, 21 ipsilateral cerebrovascular ischemic events were identified. Twelve new ipsilateral brain infarcts were identified on the 2-year neuro MRI. There was no association for IPH SIR or IPH volume with the clinical endpoint (hazard ratio (HR): 0.89 [95% confidence interval: 0.67–1.10] and HR: 0.91 [0.69–1.19] per 100-µL increase, respectively) nor with the imaging-based endpoint (odds ratio (OR): 1.04 [0.75–1.45] and OR: 1.21 [0.87–1.68] per 100-µL increase, respectively). Conclusion: IPH SIR and IPH volume were not associated with future ipsilateral ischemic cerebrovascular events. Therefore, quantitative assessment of IPH of SIR and volume does not seem to provide additional value beyond the presence of IPH for stroke risk assessment. Trial registration: The PARISK study was registered on ClinicalTrials.gov with ID NCT01208025 on September 21, 2010 (https://clinicaltrials.gov/study/NCT01208025).</p

Changes in intra- and extracranial carotid plaque calcification: a 2-year follow-up study

Extra- and intracranial carotid plaque calcification might have plaque-stabilizing effects, yet information on changes in plaque calcification remains scarce. We evaluated changes in carotid plaque calcification over 2 years follow-up in patients with symptomatic carotid artery disease. This study is based on the PARISK-study, a multicenter cohort study, with TIA/minor stroke patients with ipsilateral mild-to-moderate carotid artery stenosis (< 70%). We included 79 patients (25% female, mean age 66 years) who underwent CTA imaging with 2 year interval. We assessed the volume of extra- and intracranial carotid artery calcification (ECAC and ICAC) and calculated the difference between baseline and follow-up ECAC and ICAC volume. We performed multivariable regression analyses to investigate the association between change of ECAC or ICAC with cardiovascular determinants. ECAC. We found increase (46.2%) and decrease (34%) in ECAC volume during 2 year follow-up, both significantly correlation with baseline ECAC volume (OR = 0.72, 95% CI 0.58-0.90 respectively OR = 2.24, 95% CI 1.60-3.13).We found significant correlation for change in ECAC volume with diabetes (β = 0.46, 95% CI 0.03-0.89) and baseline ECAC volume (β = 0.81, 95% CI 0.73-0.88). ICAC. We found increase (45.0%) and decrease (25.0%) in ICAC volume. The ICAC decrease was significantly correlated with baseline ICAC volume (OR = 2.17, 95% CI 1.48-3.16), age (OR = 2.00, 95% CI 1.19-3.38) and use of antihypertensive drugs (OR = 3.79, 95% CI 1.20-11.96]).The overall change of ICAC volume was also significantly correlated with diabetes (β = 0.92, 95% CI 1.59-7.02), use of oral hypoglycemic drugs (β = 0.86, 95% CI 0.12-1.59) and baseline ICAC volume (β = 0.71, 95% CI 0.55-0.87). We provide novel insights into the dynamics of carotid plaque calcification in symptomatic stroke patients

Signal intensity and volume of carotid intraplaque hemorrhage on magnetic resonance imaging and the risk of ipsilateral cerebrovascular events: The Plaque At RISK (PARISK) study

Background: The Plaque At RISK (PARISK) study demonstrated that patients with a carotid plaque with intraplaque hemorrhage (IPH) have an increased risk of recurrent ipsilateral ischemic cerebrovascular events. It was previously reported that symptomatic carotid plaques with IPH showed higher IPH signal intensity ratios (SIR) and larger IPH volumes than asymptomatic plaques. We explored whether IPH SIR and IPH volume are associated with future ipsilateral ischemic cerebrovascular events beyond the presence of IPH. Methods: Transient ischemic attack and ischemic stroke patients with mild-to-moderate carotid stenosis and an ipsilateral IPH-positive carotid plaque (n = 89) from the PARISK study were included. The clinical endpoint was a new ipsilateral ischemic cerebrovascular event during 5 years of follow-up, while the imaging-based endpoint was a new ipsilateral brain infarct on brain magnetic resonance imaging (MRI) after 2 years (n = 69). Trained observers delineated IPH, a hyperintense region compared to surrounding muscle tissue on hyper T1-weighted magnetic resonance images. The IPH SIR was the maximal signal intensity in the IPH region divided by the mean signal intensity of adjacent muscle tissue. The associations between IPH SIR or volume and the clinical and imaging-based endpoint were investigated using Cox proportional hazard models and logistic regression, respectively. Results: During 5.1 (interquartile range: 3.1–5.6) years of follow-up, 21 ipsilateral cerebrovascular ischemic events were identified. Twelve new ipsilateral brain infarcts were identified on the 2-year neuro MRI. There was no association for IPH SIR or IPH volume with the clinical endpoint (hazard ratio (HR): 0.89 [95% confidence interval: 0.67–1.10] and HR: 0.91 [0.69–1.19] per 100-µL increase, respectively) nor with the imaging-based endpoint (odds ratio (OR): 1.04 [0.75–1.45] and OR: 1.21 [0.87–1.68] per 100-µL increase, respectively). Conclusion: IPH SIR and IPH volume were not associated with future ipsilateral ischemic cerebrovascular events. Therefore, quantitative assessment of IPH of SIR and volume does not seem to provide additional value beyond the presence of IPH for stroke risk assessment. Trial registration: The PARISK study was registered on ClinicalTrials.gov with ID NCT01208025 on September 21, 2010 (https://clinicaltrials.gov/study/NCT01208025)