Falling film evaporation on horizontal tubes with smooth and structured surfaces

The present study includes the development of a model for falling film evaporation on a horizontal plain tube and extensive experimental tests for tubes with plain and commercial structured surfaces in a spray evaporator. The model defines heat transfer in three distinct regions: the jet impingement region, the thermal developing region, and the fully developed region. The heat transfer coefficient in the thermal developing region was estimated by considering one-dimensional transient heat conduction across the film. The developed heat transfer coefficient was calculated by solving Nusselt\u27s problem for film evaporation. Compared with experimental data, the present model predicted data in good agreement with experiment;Heat transfer within a test cylinder heated by a cartridge heater was analyzed. Spray evaporation tests using electrically heated test sections with smooth, GEWA-T, Thermoexcel-E, and High Flux surfaces were conducted to investigate the effects of liquid supply mode, surface structure, surface aging, surface subcooling, heat flux, film flowrate, liquid feed height, and rate of heat flux change. Complementary pool boiling experiments were also conducted;The falling film evaporation provides heat transfer coefficients higher than the natural convection that characterizes pool boiling at low superheats. The falling film evaporation data for the structured surfaces merge with the respective pool boiling curves at high heat flux. High Flux and Thermoexcel-E surfaces are characterized by incipient boiling at low superheats and high boiling coefficients, realized by internal thin film evaporation. The first-stage nucleate boiling on the Thermoexcel-E surface before normal boiling is described for the first time. GEWA-T surfaces primarily enhance the convective heat transfer through extended surface and surface tension effects. In both falling film evaporation and pool boiling on Thermoexcel-E, a pre-dried surface presents higher normal heat transfer coefficients than those from a preboiled surface. Also, slowly increasing the heat flux results in normal coefficients higher than those obtained with step changes in power. Film flowrate and liquid feed height have small effects on non-boiling convection. The effects vanish when boiling is dominant. Also it was found that fouling is a serious problem with the High Flux porous surface when boiling water

Complementary and Alternative Exercises for Management of Osteoarthritis

Osteoarthritis (OA) is a chronic condition characterized by degeneration of cartilage and its underlying bone within a joint. With no cure currently available, the goals of treating OA are to alleviate pain, maintain, or improve joint mobility, increase the muscle strength of the joints, and minimize the disabling effects of the disease. Recent research has suggested that complementary and alternative medicine (CAM) exercises may improve OA symptoms. This paper covers CAM mind-body exercises—Tai Chi, qigong, and yoga—for OA management and evaluates their benefits in pain reduction, muscle strength, physical function, stiffness, balance, fear of falling, self-efficacy, quality of life, and psychological outcomes in patients with OA, based on randomized controlled trials published. Findings from the literature suggest that CAM exercises demonstrate considerable promise in the management of OA. Future studies require rigorous randomized controlled trials with larger sample sizes

Green tea polyphenols and Tai Chi for bone health: Designing a placebo-controlled randomized trial

BACKGROUND: Osteoporosis is a major health problem in postmenopausal women. Evidence suggests the importance of oxidative stress in bone metabolism and bone loss. Tea consumption may be beneficial to osteoporosis due to its antioxidant capability. However, lack of objective data characterizing tea consumption has hindered the precise evaluation of the association between tea ingestion and bone mineral density in previous questionnaire-based epidemiological studies. On the other hand, although published studies suggest that Tai Chi (TC) exercise can benefit bone health and may reduce oxidative stress, all studies were conducted using a relatively healthy older population, instead of a high-risk one such as osteopenic postmenopausal women. Therefore, this study was designed to test an intervention including green tea polyphenol (GTP) and TC exercise for feasibility, and to quantitatively assess their individual and interactive effects on postmenopausal women with osteopenia. METHODS/DESIGN: One hundred and forty postmenopausal women with osteopenia (defined as bone mineral density T-score at the spine and/or hip between 1 to 2.5 SD below the reference database) were randomly assigned to 4 treatment arms: (1) placebo group receiving 500 mg medicinal starch daily, (2) GTP group receiving 500 mg of GTP per day, (3) placebo+TC group receiving both placebo treatment and TC training (60-minute group exercise, 3 times per week), and (4) GTP+TC group receiving both GTP and TC training for 24 weeks. The outcome measures were bone formation biomarker (serum bone alkaline phosphatase), bone resorption biomarker (serum tartrate resistant acid phosphatase), and oxidative DNA damage biomarker (urinary 8-hydroxy-2'-deoxyguanosine). All outcome measures were determined at baseline, 4, 12, and 24 weeks. Urinary and serum GTP concentrations were also determined at baseline, 4, 12, and 24 weeks for bioavailability. Liver function was monitored monthly for safety. A model of repeated measurements with random effect error terms was applied. Traditional procedures such as ANCOVA, chi-squared analysis, and regression were used for comparisons. DISCUSSION: We present the rationale, design, and methodology of a placebo-controlled randomized trial to investigate a new complementary and alternative medicine strategy featuring a dietary supplement and a mind-body exercise for alleviating bone loss in osteopenic postmenopausal women. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT0062539

Green tea polyphenols supplementation and Tai Chi exercise for postmenopausal osteopenic women: safety and quality of life report

<p>Abstract</p> <p>Background</p> <p>Evidence suggests that both green tea polyphenols (GTP) and Tai Chi (TC) exercise may benefit bone health in osteopenic women. However, their safety in this population has never been systematically investigated. In particular, there have been hepatotoxicity concerns related to green tea extract. This study was to evaluate the safety of 24 weeks of GTP supplementation combined with TC exercise in postmenopausal osteopenic women, along with effects on quality of life in this population.</p> <p>Methods</p> <p>171 postmenopausal women with osteopenia were randomly assigned to 4 treatment arms for 24 weeks: (1) Placebo (500 mg starch/day), (2) GTP (500 mg GTP/day), (3) Placebo + TC (placebo plus TC training at 60 min/session, 3 sessions/week), and (4) GTP + TC (GTP plus TC training). Safety was examined by assessing liver enzymes (aspartate aminotransferase, alanine aminotransferase), alkaline phosphatase, and total bilirubin at baseline and every 4 weeks. Kidney function (urea nitrogen and creatinine), calcium, and inorganic phosphorus were also assessed at the same times. Qualify of life using SF-36 questionnaire was evaluated at baseline, 12, and 24 weeks. A mixed model of repeated measures ANOVA was applied for analysis.</p> <p>Results</p> <p>150 subjects completed the study (12% attrition rate). The compliance rates for study agents and TC exercise were 89% and 83%, respectively. Neither GTP supplementation nor TC exercise affected liver or kidney function parameters throughout the study. No adverse event due to study treatment was reported by the participants. TC exercise significantly improved the scores for role-emotional and mental health of subjects, while no effect on quality of life was observed due to GTP supplementation.</p> <p>Conclusions</p> <p>GTP at a dose of 500 mg/day and/or TC exercise at 3 hr/week for 24 weeks appear to be safe in postmenopausal osteopenic women, particularly in terms of liver and kidney functions. TC exercise for 24 weeks (3 hr/wk) significantly improved quality of life in terms of role-emotional and mental health in these subjects. ClinicalTrials.gov identifier: NCT00625391.</p

Healthcare Engineering Defined: A White Paper

Engineering has been playing an important role in serving and advancing healthcare. The term "Healthcare Engineering" has been used by professional societies, universities, scientific authors, and the healthcare industry for decades. However, the definition of "Healthcare Engineering" remains ambiguous. The purpose of this position paper is to present a definition of Healthcare Engineering as an academic discipline, an area of research, a field of specialty, and a profession. Healthcare Engineering is defined in terms of what it is, who performs it, where it is performed, and how it is performed, including its purpose, scope, topics, synergy, education/training, contributions, and prospects

A non-competitive martial arts exercise program for health and fitness in the general population

Although traditional martial arts training focuses on defensive and offensive systems of physical techniques for combat, martial arts can be practiced as a physical activity for health and fitness, and are recommended as such by US Centers for Disease Control and Prevention. However, limited information on non-competitive martial arts exercise programs is available in the open literature. Compared with other modalities of exercise, martial arts exercise offers advantages in safety, no equipment required, flexible space requirement, adjustable intensity, comprehensiveness, individuality, exercise when watching television, and higher motivation of adherence. This article introduces a structured, systematic, and comprehensive martial arts exercise program suitable for the general population of different age groups and physical conditions. The curriculum features a non-competitive, non-contact, safe and fun personal/group exercise based on traditional martial arts training, covering a wide spectrum of techniques of hand strikes, kicks, elbow strikes, knee strikes, blocks, their combinations, takedowns/throws, and self-defense, in addition to warm-up and cool-down. The purpose is to provide an easy, safe, cost-effective (virtually no-cost) and user-friendly alternative exercise program to help the general population increase quality daily exercise

Falling film evaporation on horizontal tubes with smooth and structured surfaces

The present study includes the development of a model for falling film evaporation on a horizontal plain tube and extensive experimental tests for tubes with plain and commercial structured surfaces in a spray evaporator. The model defines heat transfer in three distinct regions: the jet impingement region, the thermal developing region, and the fully developed region. The heat transfer coefficient in the thermal developing region was estimated by considering one-dimensional transient heat conduction across the film. The developed heat transfer coefficient was calculated by solving Nusselt's problem for film evaporation. Compared with experimental data, the present model predicted data in good agreement with experiment;Heat transfer within a test cylinder heated by a cartridge heater was analyzed. Spray evaporation tests using electrically heated test sections with smooth, GEWA-T, Thermoexcel-E, and High Flux surfaces were conducted to investigate the effects of liquid supply mode, surface structure, surface aging, surface subcooling, heat flux, film flowrate, liquid feed height, and rate of heat flux change. Complementary pool boiling experiments were also conducted;The falling film evaporation provides heat transfer coefficients higher than the natural convection that characterizes pool boiling at low superheats. The falling film evaporation data for the structured surfaces merge with the respective pool boiling curves at high heat flux. High Flux and Thermoexcel-E surfaces are characterized by incipient boiling at low superheats and high boiling coefficients, realized by internal thin film evaporation. The first-stage nucleate boiling on the Thermoexcel-E surface before normal boiling is described for the first time. GEWA-T surfaces primarily enhance the convective heat transfer through extended surface and surface tension effects. In both falling film evaporation and pool boiling on Thermoexcel-E, a pre-dried surface presents higher normal heat transfer coefficients than those from a preboiled surface. Also, slowly increasing the heat flux results in normal coefficients higher than those obtained with step changes in power. Film flowrate and liquid feed height have small effects on non-boiling convection. The effects vanish when boiling is dominant. Also it was found that fouling is a serious problem with the High Flux porous surface when boiling water.</p

On the Optimal Whole-Body Vibration Protocol for Muscle Strength

The application of Whole Body Vibration (WBV) has been demonstrated to be effective in improving muscle strength/power by a number of studies, but an optimal training protocol has never been established. This paper presents a review of studies on the effects of WBV on muscles and an analysis of data to identify the optimal protocols for the most beneficial neuromuscular responses in terms of vibration frequency, amplitude, knee flexion angle, body posture (standing, sitting, supine, prone), muscle type (quadriceps, hamstrings), and vibration mode (superoinferior, anteroposterior, rotational). Ninety articles were selected for final review from initially selected 2093 articles using PRISMA guidelines. The findings suggest that the beneficial effects of WBV increase with frequency and amplitude but the optimal frequency and amplitude have not been established. The effect of the knee flexion angle is not clear. The optimal WBV protocol should be determined by considering the adverse effects of WBV on all parts of the human body including that related to head acceleration. WBV in sitting or lying positions may provide a better muscle response than standing. Directions for future research are discussed with regard to establishing the optimal WBV protocol as a safe and effective therapeutic/exercise modality for improving muscle strength and health

Epileptic Seizure Detection and Prediction Based on Continuous Cerebral Blood Flow Monitoring – a Review

Epilepsy is the third most common neurological illness, affecting 1% of the world’s population. Despite advances in medicine, about 25 to 30% of the patients do not respond to or cannot tolerate the severe side effects of medical treatment, and surgery is not an option for the majority of patients with epilepsy. The objective of this article is to review the current state of research on seizure detection based on cerebral blood flow (CBF) data acquired by thermal diffusion flowmetry (TDF), and CBF-based seizure prediction. A discussion is provided on the applications, advantages, and disadvantages of TDF in detecting and localizing seizure foci, as well as its role in seizure prediction. Also presented are an overview of the present challenges and possible future research directions (along with methodological guidelines) of the CBF-based seizure detection and prediction methods