A study of water-mist recirculation system for filtration and cooling effect in the kitchen hood ventilation system

Water-mist spray system in several heavy-duty kitchen hood canopies are installed to efficiently control the high heat loads and grease emissions produced from the cooking process and for safety purposes. Cold water is used in the water�mist system and work as a mist curtain inside the exhaust plenum of the canopy. The main purpose of this study is to reduce the water consumption by introducing the water-mist recirculation system to replace the current method water-mist system since it is working as water loss. A standard ASTM 2519 and UL 1046 full-scaled experiment was developed in the laboratory. An existing Halton Europe/Asian water�mist operating system was adopted in this study. Twelve (12) cycles (at 24 hours water-mist activation) has been studied to determine the maximum water-mist activation cycle. The data was collected at two (2) hours water-mist activation at every water-mist recirculation cycle. The water-mist spray fluids viscosity is 0.7 cP from fresh water until the 4th cycle (8 hours water-mist spray) and increase 14.29% (0.8 cP) at 5th cycle to 12th cycle. On average, the difference in gas emissions percentage for CO concentration between fresh water until 4th cycle is 10.81 – 18.92% while the CO2 concentration is 12.33 – 18.22%. On average, the difference in cooling effects percentage for ducting temperature between fresh water until 4th cycle was 5.55% while the hood temperature was 2.33%. From the study, the water-mist recirculation system could save up to 611,667 liter per year and 466,798.5 liter per year water for all U.S, European, and Asian kitchen hood designs per hood length. By adopting the new water-mist recirculation system to the current water-mist kitchen hood, the water operational cost for water successfully reduced to RM 4,889.63 per year and RM 6,977.86 per year for U.S design and European or Asian design per hood length respectively. The water-mist recirculation system has great potential to improve the current water-mist system for the commercial kitchen hoo

Pengaruh geometri mekanisme jet denyut terhadap kadar pemindahan haba

Suatu kajian melalui eksperimen dijalankan untuk menentukan kesan diameter muncung, geometri injap silinder berputar denyut (kitar tugas), jarak jet-ke-plat, dan frekuensi denyut yang keluar dari muncung terhadap pengagihan pemindahan haba tempatan pada plat tembaga pensantakan yang rata dan licin. Dua diameter muncung yang berbeza iaitu 15 mm dan 20 mm yang mana setiap satunya berbentuk bulat telah digunakan dalam kajian ini. Nombor Reynolds yang digunakan dalam jakian ini adalah berdasarkan diameter hidraulik (d) iaitu 16000 dan nisbah jarak jet-ke-plat terhadap diameter muncung yang digunakan dari 2 hingga 4. Bahagian pertama kajian ini ialah menentukan profil halaju jet udara denyut bulat pada frekuensi denyut, diameter muncung, kitar tugas, dan jarak jet-ke-plat yang berbeza. Denyutan jet udara dihasilkan oleh mekanisme injap silinder berputar dengan kitar tugas 0.29, 0.45, 0.55, dan 0.67 pada frekuensi antara 10 hingga 60 Hz. Struktur aliran mantap dan denyut tunggal bulat simetri sepaksi halaju jet udara diukur dengan menggunakan anemometer dawai-panas yang ditentukur. Nombor Nusselt tempatan jet udara santakan pada plat sasaran dikira dari nilai suhu dan fluks haba yang dicatatkan. Fluks haba dan suhu jet udara santakan pada plat sasaran diukur dengan menggunakan pengganding suhu jenis-T dan pengesan fluks haba pada kedudukan jejari yang berbeza. Keputusan yang diperolehi menunjukkan bahawa pada diameter muncung 20 mm, pemindahan haba di titik genangan jet denyutan adalah 14% lebih tinggi daripada jet mantap pada kitar tugas yang lebih tinggi iaitu 0.67, jarak jet-ke-plat 4 diameter muncung, dan frekuensi denyut 30 Hz. Pada diameter muncung 15 mm, pemindahan haba di titik genangan jet denyut adalah 6% lebih tinggi daripada jet mantap pada kitar tugas yang lebih rendah iaitu 0.29, jarak jet-ke-plat 2 diameter muncung, dan frekuensi denyut 20 Hz. Dalam setiap kes, kitar tugas yang menghasilkan peningkatan pemindahan haba adalah bergantung kepada setiap parameter aliran yang dikawal

A Study On Aircraft Air-Conditioning System Trainer Model AS-43 For Aeronautical Engineering Student Practice

Aircraft air conditioning systems are crucial for ensuring a comfortable and safe environment for occupants during flight. These systems regulate temperature, humidity, and air pressure within the cabin and are found in various aircraft types, including commercial airliners, business jets, military aircraft, and helicopters. The objectives of the research are to identify suitable standard operating procedures (SOPs) and safety protocols for the trainer system, and to determine temperature, relative humidity, pressure, and enthalpy changes within the AS-43 system. A varying parameter is temperatures, pressure, relative humidity and the enthalpy can be obtained. Manual Cool and Auto cool mode of the AS-43 trainer are evaluated. The experimental results show the Manual Cool and Auto Cool gives a slightly different enthalpy values and COP for the system. The enthalpy obtained from the Manual cool are between 240 kJ/kg to 450 kJ/kg while Auto Cool enthalpy is between 240 kJ/kg to 440 kJ/kg. The relative humidity of both modes is in average range suggested by ASHRAE. P-h diagram of both experiments can be obtained based on the data collected. Finally, the study focuses on the AS-43 Aircraft Air Conditioning System Trainer Model, which serves as a valuable educational tool for teaching students about aircraft air conditioning systems. Hence, a significant recommendation is suggested discussed at the end of the research

A Study on Aircraft Heating System Trainer Model AS-43 for Aeronautical Engineering Students Practice

The Model AS-43 Heating system trainer is a fully operational model of a light aircraft heating system demonstrating the combustion air heater method. Heat transfer is related to the mechanism that happens in this process. This study aims to utilize the Trainer Model AS-43 for practical experiments in aeronautical engineering education. The research objectives include developing standard operating procedures, determining system parameters, and proposing improvements. The significance of the study lies in enhancing the teaching scope for aeronautical engineering students and improving the Aircraft Heating System Trainer Model AS-43. The obtained results and calculations serve as valuable data for aeronautical engineering education and can facilitate further analysis and improvements in the field. Recommendations were made to enhance the trainer's utilization, including incorporating appropriate measuring tools. Implementing these recommendations would maximize the trainer's educational potential, allowing it to be utilized as an effective teaching tool for mechanical and aeronautical engineering courses. The proposed changes could improve students' comprehension, promoting better learning outcomes and advancing aviation education

Computational Modelling to Predict the Pressure Loss Coefficient of Pipe Fitting at KKTDI

Water pipeline system has an important role in delivering water throughout the whole community using piping system. If there is any leakages or damages in any part of the water pipeline system will not only cause problem in delivering water but also could cause cost damage and affect the daily life of the community. The main objective of this research is to investigate the flow characteristics in the pipeline at Kolej Kediaman Tun Dr. Ismail (KKTDI) and to investigate the pressure drop due effect due to leakage along the pipeline system. The second objective is to assess the CFD approaches to calculate the pressure loss coefficients. Computational Fluid Modelling (CFD) simulations used to predict the flow variables such as velocity, pressure by solving the mathematical equations describing the relationship between the flow variables. This program is used in this research to determine the pressure loss coefficients using simulations. The pressure loss coefficient of the piping system is around 33.8 to 50.4 while the average pressure loss coefficient of the plotted graph is 13.1. In conclusion, the pipeline system of KKTDI residential college is studied carefully to determine the pressure loss coefficient and the objective is achieved

Measurement of CO, CO2, Particulate Matter (PM10), Cockpit and Ambient Temperature, Humidity and Noise Level at UTHM Hangar

This study is focussed on works that are done at the hangar and its effect on human health. The absence of proper air quality or noise level study at the current UTHM hangar has inspired to conduct this study. The objective of this study is to measure the emission rate of carbon monoxide (CO), carbon dioxide (CO2), particulate matter (PM10), and measure the cockpit temperature, ambient temperature, humidity, and noise level of PT6A-20 engine to obtain the data at the Universiti Tun Hussein Onn Malaysia (UTHM) Hangar. There are presence of 2 engines which are Lycoming O-360 and turboprop PT6A-20 at the hangar. Lycoming O-360 uses avgas and turboprop PT6A-20 uses jetA1 fuel type which will produce higher rate of emission and that is the reason of PT6A-20 engine being chosen. So this study aims to highlight a comprehensive data of CO, CO2, particulate matter (PM10), cockpit and ambient temperature, humidity and noise level regarding the turboprop PT6A-20 engine at hangar of UTHM to aid future researchers and ensure the air quality and safety rules of the hangar. The air quality standards are used as guideline are the Malaysia Ambient Air Quality Standard and Indoor Air Quality Standard based on the Department of Occupational Safety and Health (DOSH). Also, Occupational Safety and Health (Noise Exposure) Regulations 2019 is used as the standard for noise level. Q-Trak Plus IAQ Monitor model 8554 is used to measure the emission rate of CO,CO2, level of humidity and cockpit temperature. Dust Trak Aerosol Monitor is used to measure the emission rate of PM10, Pico Data Logger is used to measure the ambient temperature and finally 1352H integrating sound level meter was used to measure the noise level of PT6A-20 engine. Based on the results produced, only carbon monoxide and carbon dioxide are below than the safety limit. The othe 5 parameters which are PM10, cockpit and ambient temperature, humidity and noise level are above the allowable limit according to DOSH

Repositioning of the global epicentre of non-optimal cholesterol

High blood cholesterol is typically considered a feature of wealthy western countries(1,2). However, dietary and behavioural determinants of blood cholesterol are changing rapidly throughout the world(3) and countries are using lipid-lowering medications at varying rates. These changes can have distinct effects on the levels of high-density lipoprotein (HDL) cholesterol and non-HDL cholesterol, which have different effects on human health(4,5). However, the trends of HDL and non-HDL cholesterol levels over time have not been previously reported in a global analysis. Here we pooled 1,127 population-based studies that measured blood lipids in 102.6 million individuals aged 18 years and older to estimate trends from 1980 to 2018 in mean total, non-HDL and HDL cholesterol levels for 200 countries. Globally, there was little change in total or non-HDL cholesterol from 1980 to 2018. This was a net effect of increases in low- and middle-income countries, especially in east and southeast Asia, and decreases in high-income western countries, especially those in northwestern Europe, and in central and eastern Europe. As a result, countries with the highest level of non-HDL cholesterol-which is a marker of cardiovascular riskchanged from those in western Europe such as Belgium, Finland, Greenland, Iceland, Norway, Sweden, Switzerland and Malta in 1980 to those in Asia and the Pacific, such as Tokelau, Malaysia, The Philippines and Thailand. In 2017, high non-HDL cholesterol was responsible for an estimated 3.9 million (95% credible interval 3.7 million-4.2 million) worldwide deaths, half of which occurred in east, southeast and south Asia. The global repositioning of lipid-related risk, with non-optimal cholesterol shifting from a distinct feature of high-income countries in northwestern Europe, north America and Australasia to one that affects countries in east and southeast Asia and Oceania should motivate the use of population-based policies and personal interventions to improve nutrition and enhance access to treatment throughout the world.Peer reviewe

Height and body-mass index trajectories of school-aged children and adolescents from 1985 to 2019 in 200 countries and territories: a pooled analysis of 2181 population-based studies with 65 million participants

Summary Background Comparable global data on health and nutrition of school-aged children and adolescents are scarce. We aimed to estimate age trajectories and time trends in mean height and mean body-mass index (BMI), which measures weight gain beyond what is expected from height gain, for school-aged children and adolescents. Methods For this pooled analysis, we used a database of cardiometabolic risk factors collated by the Non-Communicable Disease Risk Factor Collaboration. We applied a Bayesian hierarchical model to estimate trends from 1985 to 2019 in mean height and mean BMI in 1-year age groups for ages 5–19 years. The model allowed for non-linear changes over time in mean height and mean BMI and for non-linear changes with age of children and adolescents, including periods of rapid growth during adolescence. Findings We pooled data from 2181 population-based studies, with measurements of height and weight in 65 million participants in 200 countries and territories. In 2019, we estimated a difference of 20 cm or higher in mean height of 19-year-old adolescents between countries with the tallest populations (the Netherlands, Montenegro, Estonia, and Bosnia and Herzegovina for boys; and the Netherlands, Montenegro, Denmark, and Iceland for girls) and those with the shortest populations (Timor-Leste, Laos, Solomon Islands, and Papua New Guinea for boys; and Guatemala, Bangladesh, Nepal, and Timor-Leste for girls). In the same year, the difference between the highest mean BMI (in Pacific island countries, Kuwait, Bahrain, The Bahamas, Chile, the USA, and New Zealand for both boys and girls and in South Africa for girls) and lowest mean BMI (in India, Bangladesh, Timor-Leste, Ethiopia, and Chad for boys and girls; and in Japan and Romania for girls) was approximately 9–10 kg/m2. In some countries, children aged 5 years started with healthier height or BMI than the global median and, in some cases, as healthy as the best performing countries, but they became progressively less healthy compared with their comparators as they grew older by not growing as tall (eg, boys in Austria and Barbados, and girls in Belgium and Puerto Rico) or gaining too much weight for their height (eg, girls and boys in Kuwait, Bahrain, Fiji, Jamaica, and Mexico; and girls in South Africa and New Zealand). In other countries, growing children overtook the height of their comparators (eg, Latvia, Czech Republic, Morocco, and Iran) or curbed their weight gain (eg, Italy, France, and Croatia) in late childhood and adolescence. When changes in both height and BMI were considered, girls in South Korea, Vietnam, Saudi Arabia, Turkey, and some central Asian countries (eg, Armenia and Azerbaijan), and boys in central and western Europe (eg, Portugal, Denmark, Poland, and Montenegro) had the healthiest changes in anthropometric status over the past 3·5 decades because, compared with children and adolescents in other countries, they had a much larger gain in height than they did in BMI. The unhealthiest changes—gaining too little height, too much weight for their height compared with children in other countries, or both—occurred in many countries in sub-Saharan Africa, New Zealand, and the USA for boys and girls; in Malaysia and some Pacific island nations for boys; and in Mexico for girls. Interpretation The height and BMI trajectories over age and time of school-aged children and adolescents are highly variable across countries, which indicates heterogeneous nutritional quality and lifelong health advantages and risks

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Worldwide trends in hypertension prevalence and progress in treatment and control from 1990 to 2019: a pooled analysis of 1201 population-representative studies with 104 million participants.

BACKGROUND: Hypertension can be detected at the primary health-care level and low-cost treatments can effectively control hypertension. We aimed to measure the prevalence of hypertension and progress in its detection, treatment, and control from 1990 to 2019 for 200 countries and territories. METHODS: We used data from 1990 to 2019 on people aged 30-79 years from population-representative studies with measurement of blood pressure and data on blood pressure treatment. We defined hypertension as having systolic blood pressure 140 mm Hg or greater, diastolic blood pressure 90 mm Hg or greater, or taking medication for hypertension. We applied a Bayesian hierarchical model to estimate the prevalence of hypertension and the proportion of people with hypertension who had a previous diagnosis (detection), who were taking medication for hypertension (treatment), and whose hypertension was controlled to below 140/90 mm Hg (control). The model allowed for trends over time to be non-linear and to vary by age. FINDINGS: The number of people aged 30-79 years with hypertension doubled from 1990 to 2019, from 331 (95% credible interval 306-359) million women and 317 (292-344) million men in 1990 to 626 (584-668) million women and 652 (604-698) million men in 2019, despite stable global age-standardised prevalence. In 2019, age-standardised hypertension prevalence was lowest in Canada and Peru for both men and women; in Taiwan, South Korea, Japan, and some countries in western Europe including Switzerland, Spain, and the UK for women; and in several low-income and middle-income countries such as Eritrea, Bangladesh, Ethiopia, and Solomon Islands for men. Hypertension prevalence surpassed 50% for women in two countries and men in nine countries, in central and eastern Europe, central Asia, Oceania, and Latin America. Globally, 59% (55-62) of women and 49% (46-52) of men with hypertension reported a previous diagnosis of hypertension in 2019, and 47% (43-51) of women and 38% (35-41) of men were treated. Control rates among people with hypertension in 2019 were 23% (20-27) for women and 18% (16-21) for men. In 2019, treatment and control rates were highest in South Korea, Canada, and Iceland (treatment >70%; control >50%), followed by the USA, Costa Rica, Germany, Portugal, and Taiwan. Treatment rates were less than 25% for women and less than 20% for men in Nepal, Indonesia, and some countries in sub-Saharan Africa and Oceania. Control rates were below 10% for women and men in these countries and for men in some countries in north Africa, central and south Asia, and eastern Europe. Treatment and control rates have improved in most countries since 1990, but we found little change in most countries in sub-Saharan Africa and Oceania. Improvements were largest in high-income countries, central Europe, and some upper-middle-income and recently high-income countries including Costa Rica, Taiwan, Kazakhstan, South Africa, Brazil, Chile, Turkey, and Iran. INTERPRETATION: Improvements in the detection, treatment, and control of hypertension have varied substantially across countries, with some middle-income countries now outperforming most high-income nations. The dual approach of reducing hypertension prevalence through primary prevention and enhancing its treatment and control is achievable not only in high-income countries but also in low-income and middle-income settings. FUNDING: WHO