Assessing the performance of air cleaning devices – A full-scale test method

Activated carbon filters have been used for purification of air and water in industrial applications. However, these technologies have not been applied to the non-industrial built environment in general and there is no standard to quantify or to classify the performance of these systems for in-duct mechanical system application. The development of a standard test procedure is a very timely effort, since it would create a benchmark for evaluating the contaminant reduction of these systems. A full-scale test facility was designed and constructed to investigate the removal effectiveness of commercial gas-phase air cleaning devices. The test rig was verified by conducting the system pre-qualification tests. These series of tests were designed to quantitatively verify the reliability of the test rig for gas filter application. These tests include air tightness, velocity uniformity, uniform dispersion of challenge contaminants, temperature and humidity control. This paper first describes the experimental set-up for testing of in-duct air cleaner systems and its verification, and then presents the experimental results of four different kinds of commercial gaseous filters.     

A genetic algorithm for solving no-wait flexible flow lines with due window and job rejection

This paper addresses a no-wait multi-stage flexible flow shop problem. There are n jobs to complete in a predetermined due window; hence, some jobs may be rejected. A mixed integer linear programming model with the objective of maximizing the total profit gained from scheduled jobs is introduced. Since the problem is NP-hard and difficult to find an optimal solution in a reasonable computational time, an efficient genetic algorithm is presented as the solution procedure. A heuristic mechanism is proposed to use in each generation of the genetic algorithms to assure the feasibility and superior quality of the obtained solutions. Computational results show that the presented approach performs considerably in terms of both quality of solutions and required runtimes.     

Thermal Properties of the Binary‐Filler Hybrid Composites with Graphene and Copper Nanoparticles

The thermal properties of epoxy‐based binary composites comprised of graphene and copper nanoparticles are reported. It is found that the “synergistic” filler effect, revealed as a strong enhancement of the thermal conductivity of composites with the size‐dissimilar fillers, has a well‐defined filler loading threshold. The thermal conductivity of composites with a moderate graphene concentration of f_g = 15 wt% exhibits an abrupt increase as the loading of copper nanoparticles approaches f_Cu ≈ 40 wt%, followed by saturation. The effect is attributed to intercalation of spherical copper nanoparticles between the large graphene flakes, resulting in formation of the highly thermally conductive percolation network. In contrast, in composites with a high graphene concentration, f_g = 40 wt%, the thermal conductivity increases linearly with addition of copper nanoparticles. A thermal conductivity of 13.5 ± 1.6 Wm^?1K^?1 is achieved in composites with binary fillers of f_g = 40 wt% and f_Cu = 35 wt%. It has also been demonstrated that the thermal percolation can occur prior to electrical percolation even in composites with electrically conductive fillers. The obtained results shed light on the interaction between graphene fillers and copper nanoparticles in the composites and demonstrate potential of such hybrid epoxy composites for practical applications in thermal interface materials and adhesives.     

能源、环境与空调制冷

１９９７年,世界上１６０多个国家在日本京都签订了有关减少温室气体排放的协议（京都协议）。该协议对缔约国的能源政策甚至经济的发展都有巨大的影响。作为能源消耗量很大的空调制冷行业,有必要对此予以充分的关注和深入研究。本研究了国内外能源环境现状和空调制冷系统与能源环境的关系,给出了对空调制系统适应新的能源结构和环境政策进行适当调整的建议。     

Effects of Flow Depth on Water Flow and Solute Transport in Furrow Irrigation: Field Data Analysis

Because of field-scale heterogeneity in soil hydraulic and solute transport properties, relatively large-scale experiments are now increasingly believed to be critical to better understand and predict the movement of water and dissolved solutes under field conditions. In this study, five field experiments were conducted on short blocked-end furrows to assess the effects of irrigation water level on water flow and solute transport in furrows. Three experiments were carried out, each of the same duration but with different amounts of water and solutes resulting from 6, 10, and 14 cm furrow water depths, designated as low, moderate, and high water levels, respectively. Two more experiments were performed with the same amounts of applied water and solute and, consequently, different durations, on furrows with depths of 6 and 10 cm of water. Results show that both the water level and the duration play an important role in transporting and distributing water and solutes in the soil profile. A positive correlation was found between water level and infiltrated amount of water or solute. Irrigation/solute application amounts increased with decreasing water level. Water and solutes were both distributed almost vertically (one-dimensionally) for the low water level and short application treatments, while they moved much more two-dimensionally with low and moderate water depths but longer application times. Irrigation with the 14 cm water level and short application time improved the distribution of water and solutes within the soil profiles, while also causing relatively less deep percolation of water and solutes as compared to low and moderate water levels and relatively long duration times.     

Oxidized vitrinites — their aromaticity,optical properties and possible detection

The behaviour of the dispersion curves of refractive and absorptive index of a vitrinite of high-volatile rank oxidized for different periods of time up to 128 days at 105 °C supports the suggestion that the aromaticity and/or condensation of the vitrinite rise when it is oxidized. Equivocal optical data previously obtained for oxidized vitrinites can probably be explained by the extensive use in earlier microscopical studies of wavelengths in the green region of the visible spectrum. Reflectivity-dispersion data indicate that there is greater possibility of distinguishing oxidized and weathered coals from fresh samples with the microscope by comparing their optical properties in the blue region of the visible spectrum or in the ultra-violet.     

Detection and classification of sleep apnea using genetic algorithms and SVM‐based classification of thoracic respiratory effort and oximetric signal features

Sleep apnea is a relatively prevalent breathing disorder characterized by temporary interruptions in airflow during sleep. There are 2 major types of sleep apnea. Obstructive sleep apnea occurs when air cannot flow through the upper airway despite efforts to breathe. Central sleep apnea occurs when the brain fails to signal to the muscles to maintain breathing. The standard diagnostic test is polysomnography, which is expensive and time consuming. The aim of this study was to design an automatic diagnostic and classifying algorithm for sleep apneas employing thoracic respiratory effort and oximetric signals. This algorithm was trained and tested applying a database of 54 subjects who had undergone polysomnography. A feature extraction stage was conducted to compute features. An optimal genetic algorithm was applied to select optimal features of these 2 kinds of signals. The classification technique was based on the support vector machine classifier to classify the selected features in 3 classes as healthy, obstructive, and central sleep apnea events. The results show that our automated classification algorithm can diagnose sleep apnea and its types with an average accuracy level of 90.2% (87.5‐95.8) in the test set and 90.9% in the validation set with high acceptable accuracy.