A Comprehensive Evaluation of Hybrid Wetting Configurations on Dropwise Condensation

The heat transfer during condensation on a surface depends on the pattern design of the surface, which can highly influence hydrophobic/hydrophilic wettability. In this study hybrid pattern designs were studied. The relationship between the droplet dynamic and the hybrid pattern design can alter the drainage rates, droplet departure frequencies, and the condensation heat transfer rates. Therefore, two series of hybrid patterned surfaces have been designed, developed, and tested during condensation of water vapor on horizontal copper tubes, and compared to complete dropwise and complete filmwise condensation samples. This is to investigate the design that provides the maximum improvement in the droplet mobility and consequently the condensation heat transfer performance. In the first series, hydrophobic circular patterns on hydrophilic background were studied, the optimum pattern sizes/ratios were found for different subcooling temperatures. However, the corresponding maximum heat transfer rates were lower than a surface with a complete dropwise condensation. In the second series, hydrophilic circular patterns on hydrophobic background were employed and strategically examined as a function of the patterns diameter and gap. The corresponding optimum diameter that provides the peak heat transfer coefficient for this series which is 12% higher than that of the complete dropwise surface was found to be 1.5 mm when the gap is 0.5 mm. In addition, findings indicate that increasing the gaps between adjacent patterns reduces the number of bridging droplets, thereby increasing the condensation rate. The optimized dimensions of 1.5 mm were found for both pattern, and gap size, which enhanced the heat transfer rate compared with the corresponding complete dropwise surface. Ultimately, changing the gap plays a more important role than changing the size of the pattern in governing the droplets departure frequency and thus the condensation heat transfer performance. Moreover, droplet dynamics and departure characteristics during condensation on horizontal copper tubes with circular patterns have been investigated based on different patterns’ sizes and the gaps between them. Initially, series hydrophobic circular patterns on hydrophilic copper tubes are tested at various subcooling temperatures and departure frequency optimum pattern sizes are found. However, it is determined that the corresponding departure frequencies are lower than complete dropwise surface. Second, series of hydrophilic circular patterns on hydrophobic copper tubes have been systematically studied based on the patterns’ size and the gaps between them and corresponding optimum designs have been found. Results indicate that the influence of the gap between the patterns on the droplet dynamic and departure frequency is significant. The results show that when the gaps between the patterns decrease, droplets from neighboring patterns are more likely to merge, resulting in lower droplet departure frequencies, velocities, and mobility. On the other hand, increasing the gaps between the patterns promotes renewal of droplets on the condensing surfaces. The droplet departure frequency on the hybrid surface with a gap of 1.5 mm is 1.37 times higher than that of 0.5 mm gap. Moreover, the renewal droplet frequencies from the patterns are strongly affected by the gap sizes. The optimum design of the hydrophobic/hydrophilic patterns to enhance droplet dynamics is studied. In addition, with regard of condensation on hybrid surfaces, the geometry of the patterns has a significant influence on droplets departure frequency and heat transfer performance. Therefore, different patterns geometries (circle, ellipse, and diamond) have been developed on horizontal copper tubes at atmospheric pressure. All the patterns have the same size, and the same identical gap between the adjacent patterns. Results show that the diamond hybrid surface has the best performance compared with elliptic, circular hybrid surfaces at the same pattern area with same neighbor gap distance between two patterns and complete dropwise condensation. However, the circle and ellipse hybrid surfaces outperform lower performance compared to complete dropwise surface. The gap between the patterns has a significant influence on droplets dynamic and heat transfer performance for all hybrid surfaces. The heat transfer rate increases with increasing the gap between the patterns on all hybrid surfaces. The heat transfer rate for the diamond hybrid surface is 40% higher than complete dropwise condensation surface when the gap is 1mm. However, the heat transfer rate for circle and ellipse hybrid surface increases with increasing the gap, but it does not advance the complete dropwise performance. This study clearly demonstrated that an optimal geometry and gap scale patterned surfaces exist regarding maximum condensation heat transfer rate and droplet departure frequency

Alarming High Levels of Energy Drinks Consumption among School Children in Hail, Northern of Saudi Arabia

Saudi Arabia (KSA) is one among the countries for top energy drink markets. Amid growing controversies globally surrounding the increasing usage of energy drinks by children, it is felt important to understand how these trends are reflected in KSA. A cross-sectional survey was conducted to explore the trends of energy drink consumption among, and differences between, middle and secondary school children, and the associated socioeconomic and behavioral factors. Randomly selected 1006 male children from secondary and middle schools from Hail region in KSA were included in the study, using a self-administered validated questionnaire. Results revealed that about 60% of school children were current energy drink consumers. Secondary school children were significantly (P<0.001) higher than middle schoolers in terms of both frequency and quantity. Concomitantly, unhealthy dietary and lifestyle behaviors were reported in significantly higher proportions (P<0.001) among secondary school children. Home was the first place for exposure for majority of children while unreliable resources were the major sources of knowledge about energy drink composition and health effects. Poor knowledge concerning energy drink composition was reported. Taste and being energized were the major driving forces for energy drink consumption. Higher disposable income on hand and poor lifestyle behaviors were all significantly associated with energy drink consumption. It can be concluded that high proportion of energy drink consumption was reported among school children in Hail, with higher proportions in secondary than middle schools. This matter raises the significance of mounting awareness of community concerning the ingredients and potential hazards of energy drinks

Generalized pustular psoriasis in a toddler with IL36RN mutation: a case report

Generalized Pustular Psoriasis (GPP) is a dermatological autoinflammatory disease that rarely occurs in children and is associated with complex genetic factors. GPP pathogenesis has been associated with mutations in IL36RN gene, which encodes an interleukin-36 receptor antagonist. GPP usually occurs without a history of psoriasis in the patients or their family members. This case report describes the clinical course of a 3-year-old toddler with GPP. The diagnosis of GPP was confirmed through a comprehensive series of examinations, and genetic testing revealed an IL36RN mutation, providing further insight into the genetic basis of the condition. This case highlights the importance of a genetic perspective for diagnosing GPP, particularly in children

Perceived Risk of falls among Acute Care Patients

Purpose: In an effort to lower the number of falls that occur among hospitalized patients, several facilities have begun introducing various fall prevention programs. However, the efficacy of fall prevention programs is diminished if patients do not consider themselves to be at risk for falls and do not follow recommended procedures. The goal of this study was to characterize how patients in four different acute care specialist services felt about their risk of falling while in the hospital. Methods: One hundred patients admitted to the study hospital with a Morse Fall Scale score of 45 or higher were given the Patient Perception Questionnaire, a tool designed to assess a patient's perception of their own fall risk, fear of falling, and motivation to take part in fall prevention efforts. Scores on the Morse Fall Scale were gathered through a historical assessment of medical records. Descriptive statistics, Pearson's correlation coefficients, and independent sample t tests were used to examine the data. Results: The average age was 65, and around half (52%) were men and half (48%) were women. Based on their ratings on the Morse Fall Scale, all 100 participants were classified as being at high risk for falls. However, only 55.5% of the individuals agreed with this assessment. The likelihood that a patient would seek assistance and the degree to which they feared falling both declined as their faith in their mobility improved. Patients hospitalized after a fall exhibited considerably lower confidence scores and greater fear scores than patients who had not been injured in a fall. Conclusions: Patients who have a high fall risk assessment score may not believe they are at risk for falls and may not take any steps to reduce their risk. The prevalence of falls in hospitals might be mitigated by the creation of a fall risk assessment technique that takes into account both objective and subjective factors

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Tyre Cavity Coupling Resonance and Countermeasures

This paper aims to investigate the coupling resonance conditions of the tyre, cavity and rim with the attachment of trim layers on the innersurface of tyre to mitigate the resonance effect. In order to validate the mathematical formulation, finite element analysis and experimental modal testing were performed to determine the frequency response function (FRF) for a tyre-wheel assembly with and without the trim layers as well as for separated tyre and rim. It was found that the resonance magnitude has been reduced when the trim layers were added. Couplings of cavity resonance to the tyre and rim were plausible due tothe proximity of their resonance frequencies. Trim materials were tested using an impedance tube to suggest the best sound absorbing materials that can be used to mitigate the tyre cavity resonance effect

Objective evaluation of interior trim effects on sound quality and noise reduction of a coupled plate cavity system

In this study, the impedance mobility and psychoacoustic analysis methods are combined to develop a structural-acoustic model of a plate-cavity coupling system. The objective is to evaluate the effect of interior trim materials on sound loudness and sharpness of a plate-cavity coupling system. The impedance mobility method is applied to calculate the pressure frequency responses of the interior acoustic field for the plate-cavity coupling system. The sound pressure results calculated by the impedance mobility method are then directly used to calculate the psychoacoustic metrics using psychoacoustic analysis method. A good agreement was found between the experimental and analytical results. The results show that the interior trim has a large influence on the distribution of the sound loudness and sharpness inside the cavity in the middle and high frequency ranges

Acoustical characterisation of porous sound absorbing materials: a review

Over the past 50 years, the characterisation of porous sound absorbing materials has been of increasing interest to both the acoustic engineers and customers. It is particularly important that acoustic engineers are able to predict the acoustical behaviour of these materials to get a quantitative measure of the acoustic energy absorption. This paper reviews the relevant literatures over this 50-year period and concludes that phenomenological models are currently the most accurate and suitable models of predicting the bulk acoustic properties in the whole audible frequency range. This review also presents the physical parameters which provide the link between the acoustical and material properties, as well as current experimental methods used to measure these parameters. Furthermore, the most common numerical methods for modelling porous materials are describe

Development of empirical models of polyfelt fibrous materials for acoustical applications

In this study, new empirical models for predicting the airflow resistivity, sound absorption coefficient of polyfelt fibrous materials have been developed. The empirical models were presented as simple power-relations by least square best fitting method of impedance tube and flow bench test data over a set of 14 samples. Two coefficients were identified for a new empirical formula to predict the airflow resistivity from the mass density and thickness of polyfelt materials and eight coefficients were identified for a new empirical formula to predict the characteristic acoustic impedance, propagation coefficients and sound absorption coefficient from the airflow resistivity. For the given mass density and thickness of a polyfelt fibrous material, the outcome proposed in this paper enables a quick and accurate evaluation of the acoustic properties of the material such as the airflow resistivity and sound absorption coefficient without a further requirement of flow bench and impedance tube tests. This is because that the predicted results from the new empirical models are closer to the measured results in the frequency range of interest than the other models in the previous work in the published literatures

Prediction of interior trim absorption using statistical energy analysis

The study and prediction of acoustic performance of interior trim materials have always been of great interest for acoustic engineers. The aim of this study was to investigate the use of statistical energy analysis (SEA) to predict the acoustic performance of interior trim materials in term of sound absorption. To accurately predict the acoustic performance by SEA, it is important to evaluate and calculate the material physical properties such as porosity, flow resistivity, tortuosity, and viscous/thermal characteristic length of interior materials. In this study, the material physical parameters were measured and estimated using standardized test and inverse methods. Alpha cabin and impedance tube were used to measure the random and normal sound absorption coefficients respectively. The computer model based on SEA method was then validated with the experiment in order to obtain correlation between simulation and measurement. The prediction of normal sound absorptions was found to be in acceptable agreement with its corresponding test data, while prediction of random sound absorptions showed a relatively poor correlation with the test data. Moreover, poor correlation has been investigated with further analysis of the parametric data to enhance the correlation