Airflow Profile Research Articles

Investigation of temperature assisted corrosion failure of an aircraft turbine blade

In this study, the root cause of a recurring corrosion problem at the tip of an internally cooled high-pressure turbine blade (HPT) of a turbofan engine was investigated. A two-pronged strategy was utilized involving (i) experimental techniques to identify the blade material and corrosion products, and (ii) computational methods to analyze the fluid flow over the blade. In the experimental thrust, an array of techniques was employed to determine the chemical composition, microstructure, corrosion products and microhardness values while the airflow, pressure distribution and thermal profile over the blade were found through computational paradigms. The blade was a Ni-based superalloy containing typical gamma (γ) and gamma prime (γ′) phases, with an average microhardness value of 389 HV at room temperature. SEM analysis of the corroded area revealed oxides of iron, calcium, magnesium, aluminium, and silicon (FCMAS) most of which were not part of the base alloy. To determine the temperature profile and pressure distribution on the blade, a conjugate heat transfer analysis using Ansys CFX was conducted. A combination of experimental data from the engine ground running test station and analytical equations was used to find the required boundary conditions for the computational analysis. Pressure distribution over the entire blade was found which showed higher flow velocities and cross flows at the blade tip which potentially cause erosion at that region in the presence of impurities in the incoming air. Temperature distribution over the entire blade was also obtained, and it was found that the highest temperatures for the internally cooled blade occurred at the tip region which were in the range of ∼1060 °C–1250 °C (average ∼1114 °C). The temperature on the tip was high enough to cause the melting of the impurities that ingress the coating and cause its degradation during thermal cycling. This exposes the base alloy to FCMAS and causes corrosion. These high temperatures (1060–1250 °C) also induced phase transformation and increased the brittleness (∼22 % increase in hardness) which aggravated the presence of corrosion and resulted in crack formation and blade rejection.

Design and Evaluation of Face Mask Filtration: Mechanisms, Formulas, and Fluid Dynamics Simulations

The global adoption of face masks as a preventive measure against the spread of the SARS-CoV-2 virus (COVID-19) has spurred extensive research into their filtration efficacy. This study begins by elucidating various mechanisms of particle penetration and comparing filtration efficiency formulas with experimental data from prior studies. This is compared to the filtration efficiency experimental measurement developed in our previous study. Moreover, it delves into fluid dynamics simulations to examine different turbulent airflow models. Specifically, it contrasts the airflow velocity distribution of the k-ω and k-ε turbulent flow models with that of a quadrant-based average velocity model developed within this research. Furthermore, the study conducts fluid dynamic simulations to assess airflow profiles for six distinct medical and non-medical face masks. The results underscore substantial disparities among the simulations, emphasising the criticality of employing accurate fluid dynamics models for evaluating airflow patterns during diverse respiratory activities such as breathing, coughing, or sneezing, thereby enhancing environmental health in the realm of infectious disease prevention.

The Influence of Window-to-Wall Ratio (WWR) on Airflow Profile for Improved Indoor Air Quality (IAQ) in a Naturally-Ventilated Workshop in a Hot-Humid Climate

Indoor air quality (IAQ) has become a major concern worldwide as indoor air pollution rapidly becomes a public health issue. IAQ plays a pivotal role in occupants' health and comfort and influences their productivity and work efficiency. Many studies have been done on IAQ of common building spaces such as offices, residential buildings, and educational institutions, but the availability of IAQ studies on workshops is limited, considering the significant implications for workers' health and performance. Thus, this paper aims to study the effectiveness of natural ventilation in a workshop based on the influence of different window-to-wall ratios (WWR). Electronic databases are utilized to obtain data, and the findings collected are categorized based on research methodology, issues, and findings. The air movement as part of the physical parameters of IAQ is studied through the application of Computational Fluid Dynamic (CFD) simulation to observe and analyse the airflow pattern and the air velocity of the naturally ventilated workshop with different WWRs. The research outcome underscores the ideal WWR for effective natural ventilation in a workshop is 0.30. However, the study observes that the effectiveness decreases as WWR exceeds 0.50. Further research on the openings' location, inlet, and outlet sizes and application of mechanical ventilation can be conducted to improve the measurement of the IAQ effectiveness in a naturally ventilated workshop.

МЕТОДИКА ВИЗНАЧЕННЯ ВІДДАЛЕНОГО ДЕСАНТУВАННЯ ПАРАШУТНО-РЕАКТИВНОЇ СИСТЕМИ

The article discusses certain issues and possible ways to partially solve the problem of remote landing, which may be useful in planning airborne operations to improve the safety of traditional parachute landing, as well as in further research and development of remote landing methods for airborne vehicles. Based on the results of the research, a method of remote landing of heavy equipment using a parachute-jet system is proposed, which allows to identify the weakest properties of the system, assess its overall level, characterised by a set of natural and climatic indicators, in particular wind speeds at different altitudes, and develop measures to improve the efficiency of the system's intended use. The results of the study demonstrate the ability of the WFD to move horizontally to the landing site at a considerable distance from the point of discharge by increasing the height of the release. However, it is much more difficult to calculate the specific amount of displacement without current knowledge of the many parameters that influence the wind drift rate. These parameters mainly include the air currents encountered by the WTG, which can help or hinder horizontal movement. Modern technology has made it possible to implement many innovative methods of cargo discharge. In order to reduce the impact of uneven airflows on drop accuracy, HARP (high-altitude release point) systems are now being used to improve the accuracy of high-altitude drops, which take into account airflow dynamics, system ballistics and aircraft speed.The ballistic table (based on the average ballistic characteristics of this parachute system) determines the drop point of the combat vehicle and calculates the free fall trajectory for a high altitude drop, taking into account the typical airflow profiles between the drop point and the landing site. To significantly improve the accuracy of high altitude drops, it is also possible to use an infrared Doppler laser locator to measure airspeed at different altitudes and create real-time 3D wind maps in the area between the aircraft and the landing site surface. Such systems are capable of making measurements with a typical error of less than one metre per second. The application of the research results in practice will increase the operational capabilities of the Airborne Assault Forces of the Armed Forces of Ukraine, namely, to ensure rapid deployment in threatened areas to deter the enemy by remotely landing heavy equipment, which in turn will significantly increase the combat potential of combat units in the operational and tactical depth of the enemy's defence.

A pilot numerical study of odorant transport to the olfactory region during sensory evaluations following ISO 16000-28

We numerically analyzed odorant transportation from a sniffing device (funnel) to the olfactory region of the nasal cavity during breathing. We followed the procedure for the perceived air quality evaluations described in the ISO 16000-28 standard, and used acetone defined as the standard test substance for pi-scale evaluations in this standard; we also used ammonia and acetic acid, as acetone also emitted by humans. We modelled two breathing conditions: normal breathing (through nose) and sniffing. We evaluated olfactory receptor access under these breathing conditions. The acetone absorption flux to the olfactory epithelial tissues was analyzed using a computer-simulated person with a numerical respiratory tract model and a physiologically based pharmacokinetic model that was used to validate the prediction accuracy. The absorption flux and sensible/latent heat flux to the olfactory epithelial tissue were analyzed quantitatively. We also analyzed the impact of flow through the ortho- and retro-nasal pathways on the absorption flux to the olfactory region. The transient inhalation/exhalation airflow profile, breathing, and sniffing conditions had a significant impact on the absorption flux to the olfactory region of the nasal cavity. We observed two peaks of odorant absorption flux in one breath one during inhalation and one during exhalation. For example, 0.5μg/(m2s) of peak acetone absorption flux in the olfactory region during inhalation and 0.1μg/(m2s) during exhalation was observed.

Condensation Zone Estimation and Determination and Comparison of Condensation by Numerical Analysis in Vehicle Lighting System

The condensation problem in automobile lighting system risks driving and driver safety. Condensation is the main cause of problems such insufficient lighting. In our study, the problem of condensation in vehicle headlights is discussed. The region where condensation will occur was estimated from the results obtained from the temperature analysis. The amount of condensed mass was calculated by the calculation method. Calculations were confirmed by numerical analysis. In the analyzes made in ANSYS 2022 R2 software, the transmission effects (conjugate effects) in the headlight components were taken into account. Boussinesq approach was used for natural convection and Monte Carlo approach was used for considering radiation effects. Mesh independence was was studied. Thermal analyzes were made at ambient temperature T∞=5 °C and RH: 95% independent of time. As a result of the analysis, the indoor air temperature distribution, air flow profiles were examined and an estimate was made where the condensation would occur. Then, the thermal analysis results were read as the initial condition, and it was kept for 300 seconds. Water at 3 °C was sprayed onto the lens. Condensation formation analyzes were made in terms of time. After the formation of condensation, the power was turned on to the lighting elements and it was expected that the condensation would be removed within 1800 seconds as per the specification. The region where condensation is predicted and the region with condensation in the analyzes are compatible with the literature.

Boundary conditions for exhaled airflow from a cough with a surgical or N95 mask.

Wearing surgical or N95 masks is effective in reducing the infection risks of airborne infectious diseases. However, in the literature there are no detailed boundary conditions for airflow from a cough when a surgical or N95 mask is worn. These boundary conditions are essential for accurate prediction of exhaled particle dispersion by computational fluid dynamics (CFD). This study first constructed a coughing manikin with an exhalation system to simulate a cough from a person. The smoke visualization method was used to measure the airflow profile from a cough. To validate the setup of the coughing manikin, the results were compared with measured data from subject tests reported in the literature. The validated coughing manikin was then used to measure the airflow boundary conditions for a cough when a surgical mask was worn and when an N95 mask was worn, respectively. Finally, this study applied the developed airflow boundary conditions to calculate person‐to‐person particle transport from a cough when masks are worn. The calculated exhaled particle patterns agreed well with the smoke pattern in the visualization experiments. Furthermore, the calculated results indicated that, when the index person wore a surgical and a N95 mask, the total exposure of the receptor was reduced by 93.0% and 98.8%, respectively.

전산해석기반 헤어드라이어 임펠러 형상 개선을 통한 유속향상 연구

In this study, structural problems of a hair dryer was analyzed by computational fluid dynamics analysis, and the structure of it was optimized by improving the impeller design. First, we measured the maximum velocity of a hair dryer for four different impeller speeds based on the KS standard (KS C 9209:2013). By analyzing the air flow profile inside the hair dryer using COMSOL Multiphysics, we confirmed that the pressure at the lower end of the impeller increased due to the stagnant flow at the lower end of the hair dryer. We solved this abnormal air flow by changing the height and angle of the impeller. We also verified the validity of the simulation by calculating the maximum air flow of a hair dryer and comparing it with that of the experiment. Consequently, we designed a hair dryer such that the maximum wind speed was improved by 34.4%-56.8%.

0786 Assessing the Adequacy of Auto Titrating Positive Airway Pressure Treatment in Patients with Severe Obstructive Sleep Apnea Diagnosed on Home Sleep Testing

Abstract Introduction Auto titrating positive airway pressure (Auto-PAP) therapy has been increasingly prescribed to treat obstructive sleep apnea (OSA) without reliance on in-laboratory PAP titration studies. Given the current pandemic and the limited use of in laboratory titrations, Auto-PAPs have been prescribed increasingly. The ability to achieve optimal control of obstructive events with Auto-PAP for patients with severe OSA (respiratory disturbance index (RDI) >30/hour of recording) on home sleep apnea testing (HSAT) has not been systematically investigated. Our study looks at the success of treatment on Auto-PAP in patients diagnosed with severe OSA on HSAT. Methods We retrospectively reviewed charts of patients who were diagnosed with severe OSA on HSAT and were prescribed an Auto-PAP at the Memorial Hermann – Texas Medical Center Sleep Disorders Center between September 2019 and May 2020. The usage data, residual AHI and adherence was assessed. Successful treatment was determined as a residual AHI (rAHI) <15. We excluded patients those who were non-adherent to PAP therapy. This study was conducted as a quality improvement initiative at our institution. Results We identified 24 patients diagnosed with severe OSA on HSAT and prescribed Auto-PAP. Nine patients were excluded due to non-adherence to Auto-PAP (37%). Of the remaining 15 patients, 80% were male, the average age was 53.7 years (range 36-69) and the average RDI on HSAT was 51.4 events/hour (SD 17.1). The average usage >4 hours was 76% in the adherent patients. The median pressure on Auto-PAP was 9 cm H2O (range 5.3-16.3). The average rAHI of 1.8 events/hour (range 0.3- 6.1). Usage data revealed only 1 patient with rAHI>5 and central apnea index of 3.9, who was then referred for an in-lab PAP titration study. Conclusion Sensors in the airway circuit of PAP devices measure airflow, vibration, and flattening of the airflow profile. Auto-adjusting PAP devices use this feedback to make online adjustments in pressure to maintain upper airway patency. Our study suggests that Auto-PAP is an effective initial therapy even for severe OSA, permitting both timely and adequate control of OSA especially when in laboratory titrations are limited. Close monitoring is however recommended to ensure adherence, and also to assess the potential emergence of central events. Support (If Any)

Numerical Investigation of the Effect of Square and Sinusoidal Waves Vibration Parameters on Heat Sink Forced Convective Heat Transfer Enhancement

Among numerous electronic cooling methods, a vibrating heat sink using sinusoidal wave vibration effectively enhances the heat transfer by disturbing the thermal boundary layer. However, sinusoidal wave vibration has reached its limits in enhancing heat transfer. The present study utilizes a new square wave-shaped vibration and numerically investigates the thermal performance of a heat sink subjected to sinusoidal and square waves vibration. It is found that using the square wave vibration is more beneficial to the thermal performance of the heat sink than the sinusoidal wave. The sudden impulsive motion of square wave vibration induces a higher randomness of the airflow profile and recirculation zones than the sinusoidal wave, causing the air flow to impinge directly into the fin surfaces, and further enhances the heat transfer. Furthermore, increasing the frequency and amplitude leads to a higher heat transfer enhancement. Moreover, square wave vibration achieves a 25% increase in Nusselt values compared to the nonvibrating fins and it is 11% higher than the Nusselt number recorded by the sinusoidal vibration. Consequently, Reynolds number values can be reduced by 42.2% to achieve the Nusselt number values of nonvibrating fins, potentially reducing the cooling system or fin size. This reduction may contribute to solving the challenges of electronic systems compactness.

Numerical simulation of natural ventilation with passive cooling by diagonal solar chimneys and windcatcher and water spray system in a hot and dry climate

The overuse of fossil fuels has become a major challenge in recent decades. Since mechanical ventilation systems are responsible for the largest proportion of the energy usage in the buildings, this study aims to come up with a green initiative for resolving the dire consequences of energy consumption. Here, for the first time, we work on an approach in which we aim to assess and enhance the evaporative cooling rate of a passive method during a summer day in a multi-story building in a hot and dry climate. In this regard, the windcatcher is coupled with three solar chimneys, and a water spray system (WSS) which is located at the entrance of the windcatcher to decrease the temperature and raise the humidity of the air entering each floor. A combination of wind-catcher, solar chimney, and water spray system is adopted to provide natural air circulation in the absence of wind. Indeed, we employ Radiation, Turbulent, and Discrete Phase Models to simulate the proposed system by CFD. The effect of different variables such as temperature, droplet diameter, and thermal comfort factors are studied. Temperature, velocity, and other airflow profiles are analyzed using ANSYS FLUENT software. The study highlighted that adding WSS leads to a roughly 6–12 °C reduction in the temperature; moreover, relative humidity will rise by 80% on the third floor. Accordingly, adding WSS can improve the system’s efficiency and satisfy the thermal comfort conditions in the absence of wind.

Heterogeneous distribution of mature olfactory sensory neurons in human olfactory epithelium.

The olfactory cleft (OC) comprising the olfactory epithelium (OE) is the most important anatomical location for olfactory function. Endoscopic sinus surgery (ESS) is used to treat diseases related to the OC and improve olfactory dysfunction. However, iatrogenic OE injury occasionally occurs. Comprehensive knowledge of the olfactory region is required to avoid damage to the OE during endoscopic procedures. Immunohistochemistry was performed on olfactory mucosa obtained from the unaffected side of olfactory neuroblastoma surgical specimens. The OE was defined as the epithelium containing mature olfactory sensory neurons (OSNs). The distribution and cell kinetics of the OE were examined. The OE was selectively localized to the anterior two-thirds of the superior turbinate (ST) and in the nasal septum (NS) just opposite to the ST; the OE was not detected within the mucosa of the superior meatus. The density of mature OSNs was high at the ethmoid tegmen but gradually decreased with distance from the ethmoid tegmen. The extent of cell death and proliferation was relatively even across the OE. Analysis of airflow profiles revealed that resection of inferior ST does not decrease airflow to the OC. The results indicate that the distribution and degree of differentiation of mature OSNs are heterogenous throughout the OE. Epithelial resection of the anterior or superior ST has the potential to damage olfactory function. Resection of the inferior or posterior ST or widening of the superior meatus is a safer alternative that does not damage mature OSNs or alter airflow to the OC.

Development of a metric for predicting people's responses to gusting wind noise in automobiles

Automobile manufacturers are trying to improve the interior noise environment in their cars. A more thorough understanding of how people perceive the noise is an important step towards this goal. The focus of the current research is on modeling the acceptability of time-varying wind noises containing gusts. A listening test was designed containing sounds that were simulated on the computer, based on pre-defined airflow profiles. The time-varying noises in the test follow one of two simple gusting scenarios. The primary scenario contained two segments of steady wind flanking a series of consecutive equal-strength gusts. The number, duration, and strength of the gusts were varied between sounds. This was done to examine general trends of acceptability with modulation rate, modulation depth, and duration. The second scenario contained two gusts of equal or unequal strength, occurring either without a break or separated by a time gap. This was done to examine the relationship between people's reactions to the individual gusts in a pattern and their reactions to the whole pattern. A small number of steady-wind noises were included for reference. Terms in an acceptability model containing a previously proposed gusting metric were estimated. Possible refinements to the metric and model are discussed.

A literature review of building energy simulation and computational fluid dynamics co-simulation strategies and its implications on the accuracy of energy predictions

The paper presents a review of existing literature in the field of coupling Computational Fluid Dynamics (CFD) with Building Energy Simulations (BES) to better predict indoor environmental conditions and building energy implications. CFD is capable of providing a detailed analysis of airflow profile and temperature gradients in the space as well as better prediction of heat transfer involving convection and radiation. Whereas BES can provide dynamically changing boundary conditions to CFD to facilitate a precise transient analysis. Combining the two simulations provides a powerful framework to accurately predict building performance parameters. The review examines the variables exchanged between the two simulations and establishes that the Convective Heat Transfer Coefficient (CHTC) as the most important exchanged variable that can significantly improve the accuracy of energy simulations. Issues regarding the application of co-simulation mechanism are then discussed in terms of simulation discontinuities, along with strategies adopted by researchers to overcome the same. In the later sections, the review evaluates the applicability of co-simulation from the perspective of year-long building energy simulations and presents an overview of methods used in research to implement the same. Finally, the conclusions are discussed and the scope for future research in the field is presented.Practical implication: The review presents a critical analysis of essentially all major coupling strategies that can be used to perform a BES-CFD coupled analysis along with their strengths, limitations and possible application scenarios. Additionally, the problems associated with establishing the co-simulation are examined and various adopted solutions are presented along with methods implemented towards extending the practical applicability of such an analysis to encapsulate year-long simulations.

Numerical study on the effect of circumferential position of ultrasonic transducers on ultrasonic cross-correlation flowmeter performance under asymmetric air flow profile

There are several ultrasonic flowmeter technologies such as transient time, cross-correlation, Doppler and etc. The performance of different types of ultrasonic flowmeters under disturbed flow profile due to elbow at upstream has been well studied recently except the cross-correlation type. The ultrasonic cross-correlation flowmeter (UCCF) has different mechanism of flow measurement in comparison with other types of ultrasonic flowmeters that strongly requires its own studies. In case of disturbed flow profile in pipe, due to asymmetrical velocity profile, the UCCF accuracy and required calibration factor are strongly dependent on the circumferential position of ultrasonic transducers on the pipe. Study on UCCF transducers circumferential position and specifying transducers proper position could incredibly improve the UCCF accuracy. The effect of transducers circumferential position on the accuracy in both single path and multipath has not been investigated for a UCCF so far. In this work, Computational Fluid Dynamics (CFD) simulations were conducted using turbulence model of RSM (Reynolds Stress Model) Stress-ω to simulate the asymmetrical air flow profile inside the elbow and the connected straight pipe in order to study the effect of circumferential position of transducers on calibration factor for special type of ultrasonic flowmeters ,UCCF, at different Reynolds numbers and various locations of flowmeter, for the first time. Moreover, the effects of Reynolds numbers and the flowmeter distances from the elbow on the calibration factor were analyzed. Finally, based on calculated calibration factors at different transducer circumferential positions, the best transducers arrangement at different flowmeter locations were proposed for single and multipath cross-correlation flowmeter. Also, in multipath ultrasonic cross correlation flowmeter, the optimum number of transducers were investigated.

Thermal performance analysis of fin-and-tube heat exchangers operating with airflow nonuniformity

This study develops a tube element method for thermal performance analysis of fin-and-tube heat exchangers operating with airflow nonuniformity. Experimental investigations have been performed on two fin-and-tube heat exchangers to validate the proposed tube element method. The heat exchanger tubes are discretized into a finite number of tube elements. These tube elements are observed as distinctive sub-exchangers, described by the appropriate heat transfer relations. The tube element method is capable of predicting the effectiveness in heat exchangers with complex tube circuitries, operating with either uniform or nonuniform airflows. The following general conclusions are obtained: the size of the effectiveness deterioration depends mainly on the heat exchanger operating point and on the degree of airflow nonuniformity. The effectiveness deterioration is highest when the heat capacity rate ratio is 1 and lowest when the heat capacity rate ratio is 0, for airflow nonuniformities with orientation perpendicular to the tube axis. The opposite is seen for airflow nonuniformities with orientation parallel to the tube axis. The heat exchanger effectiveness deterioration is up to 5.2% and 14.5% for complex nonuniform airflow profiles encountered in real-world operation, having airflow nonuniformity degrees of 0.43 and 0.81, respectively. Further, it was found that the heat exchanger tube circuitry design, the thermal resistance ratio and the airflow regime also influence the size of the effectiveness deterioration.

An integrated approach for the analysis and modeling of road tunnel ventilation. Part I: Continuous measurement of the longitudinal airflow profile

The knowledge of the flow field inside road tunnels under normal operation, let alone fire conditions, is only approximate and partial. The reason is that while the full three-dimensional, unsteady problem is out of reach of numerical methods, on the other hand accurate measurement of the airflow in road and railway tunnels constitutes an extremely demanding task. The present work, structured as a twofold study, takes up the challenge and proposes an original integrated experimental and numerical approach for the analysis and modeling of flow inside a road tunnel and its ventilation systems, aiming at defining a methodology for the creation of “digital twins” of the system itself, on which advanced ventilation and smoke control strategies can be tested and fine-tuned. In this first part, an innovative experimental facility for the continuous acquisition of the longitudinal velocity profile along the whole length of a road tunnel has been designed and built. The facility consists of a survey rake with five bidirectional vane anemometers, which is mounted on a small electric vehicle that can travel through the tunnel at constant speed. This paper reports the design procedure of the measurement facility, with particular focus on the conception and realization of the vehicle carrying the survey rake. Results of the first experimental campaign carried out under the 11611 meters long Mont Blanc road tunnel are presented to corroborate the validity of the approach adopted and the accuracy of the measurement chain.

Patient Inspiratory Maneuver Performance; Peak Lungpower, Acceleration and Volume.

Background: Use of drug delivery devices between nebulizers, dry powder inhalers (DPIs), or metered dose inhalers (MDIs), for treating patients with asthma and chronic obstructive pulmonary disease (COPD), is based on patients' capability of coordinating the inhalation maneuver and achieving sufficient airflow. There are limited data available with regard to how patients meet the requirements of successful inhalation performance, and how the concept of inspiratory lungpower could be applied. The aim of this work was to study the patient inspiratory airflow profile performance in large data sets. We analyzed how the Kamin-Haidl inhalation criteria were met by patients with DPIs such as Easyhaler for combination therapy (EH-combi), Easyhaler for monotherapy (EH-mono), Diskus, and Turbuhaler (TH), and applied peak lungpower instead of peak inspiratory flow rate as an indicator of patient performance.Materials and Methods: Data sets gathered in two previous studies for DPIs, that is, EH-combi, EH-mono, Diskus, and TH, were used to analyze how inspiratory lungpower representing inspiratory muscle power, flow acceleration, and volume after peak met the inhalation criteria. The measured patient airflow profiles through inhalers were assessed for patients with asthma or COPD.Results: Based on the Kamin-Haidl inhalation criteria, successful inhalation requirements were met with EH-combi in 96.1% and with EH-mono in 92.6% of patients. The success rates were 89.5% and 84.6% with Diskus and TH, respectively, (p < 0.0001 between devices). In patients with asthma or COPD, the mean lungpower was 7.51 and 6.15 W for EH-combi, 8.79 and 6.88 W for EH-mono, 7.18 and 4.36 W for Diskus, and 9.65 and 6.86 W for TH, respectively, when patients followed the manufacturer's written instructions.Conclusions: Lungpower applied to the Kamin-Haidl inhalation criteria concept could be an applicable method for reviewing patient performance for different DPIs despite DPIs' characteristic differences in airflow resistance. In light of these results, DPIs provide a feasible treatment option for a large majority of respiratory patients.

Evaluating Regional Pulmonary Deposition using Patient-Specific 3D Printed Lung Models.

Development of targeted therapies for pulmonary diseases is limited by the availability of preclinical testing methods with the ability to predict regional aerosol delivery. Leveraging 3D printing to generate patient-specific lung models, we outline the design of a high-throughput, in vitro experimental setup for quantifying lobular pulmonary deposition. This system is made with a combination of commercially available and 3D printed components and allows the flow rate through each lobe of the lung to be independently controlled. Delivery of fluorescent aerosols to each lobe is measured using fluorescence microscopy. This protocol has the potential to promote the growth of personalized medicine for respiratory diseases through its ability to model a wide range of patient demographics and disease states. Both the geometry of the 3D printed lung model and the air flow profile setting can be easily modulated to reflect clinical data for patients with varying age, race, and gender. Clinically relevant drug delivery devices, such as the endotracheal tube shown here, can be incorporated into the testing setup to more accurately predict a device's capacity to target therapeutic delivery to a diseased region of the lung. The versatility of this experimental setup allows it to be customized to reflect a multitude of inhalation conditions, enhancing the rigor of preclinical therapeutic testing.

External wind on the optimum designing parameters of a wall solar chimney in building

Solar chimney is a reliable renewable energy system that enhances the natural ventilation to reduce the energy consumption in buildings. Under the fact that previous optimization designs usually ignore the external wind, the impacts of external wind on the optimum designing parameters are then investigated. It is confirmed that external wind could affect its optimum designing parameters, which are different from those previously obtained value in the literature without considering the external wind. For the analysed wall solar chimney, it was known that previously obtained optimal cavity depth of 0.2–0.3 m is no longer applicable under the external wind, and the optimal value rises to 0.4–0.5 m, while the same applies to inlet height/area. Solar chimney performance is enhanced under the external wind, which is not only because of the incoming wind flow from the room opening but also the reduced air resistance. It was observed that increased solar intensity shows limited influences on the overall airflow characteristics. Solar chimney performance also presented a generally enhanced trend under a low external wind speed, but a strong wind could dominate its performance with limited fluctuation even though the wind angle is higher as 45°. It was known that the airflow rates through the solar chimney are largely hampered with a small cavity depth (i.e., smaller than 0.2 m) and inlet height under the external wind. And the airflow profiles are less affected when both of cavity depth and inlet height are bigger than 0.2 m. The obtained research outcomes could provide a technical guide on the optimization design of solar chimney in buildings.