Technology and ispection of air conditioning systems

Summary A technical approach, in terms of air quality, implies the review of all components within the air conditioning system and the check of their characteristics, as far as contamination sources are concerned. The contribution introduces the parameters to be examined and specifies the importance of validation.     

Physiological and subjective responses in the elderly when using floor heating and air conditioning systems

The purpose of this study was to investigate the effects of a floor heating and air conditioning system on thermal responses of the elderly. Eight elderly men and eight university students sat for 90 minutes in a chair under the following 3 conditions: air conditioning system (A), floor heating system (F) and no heating system (C). The air temperature of sitting head height for condition A was 25 degrees C, and the maximum difference in vertical air temperature was 4 degrees C. The air and floor temperature for condition F were 21 and 29 degrees C, respectively. The air temperature for condition C was 15 degrees C. There were no significant differences in rectal temperature and mean skin temperature between condition A and F. Systolic blood pressure of the elderly men in condition C significantly increased compared to those in condition A and F. No significant differences in systolic blood pressure between condition A and F were found. The percentage of subjects who felt comfortable under condition F was higher than that of those under condition A in both age groups, though the differences between condition F and A was not significant. Relationships between thermal comfort and peripheral (e.g., instep, calf, hand) skin temperature, and the relationship between thermal comfort and leg thermal sensation were significant for both age groups. However, the back and chest skin temperature and back thermal sensation for the elderly, in contrast to that for the young, was not significantly related to thermal comfort. These findings suggested that thermal responses and physiological strain using the floor heating system did not significantly differ from that using the air conditioning system, regardless of the subject age and despite the fact that the air temperature with the floor heating system was lower. An increase in BP for elderly was observed under the condition in which the air temperature was 15 degrees C, and it was suggested that it was necessary for the elderly people to heat the room somehow in winter. Moreover, it is particularly important for elderly people to avoid a decrease in peripheral skin temperature, and maintain awareness of the warmth of peripheral areas, such as the leg, in order to ensure thermal comfort.     

Colonization by Cladosporium spp. of painted metal surfaces associated with heating and air conditioning systems

Cladosporium cladosporioides and C. hebarum colonized painted metal surfaces of covering panels and register vents of heating, air conditioning and ventilation systems. Hyphae penetrated the paint film and developed characteristic conidiophores and conidia. The colonies were tightly appressed to the metal surface and conidia were not readily detectable via standard air sampling procedures.     

Colonization of fiberglass insulation used in heating,ventilation and air conditioning systems

Summary The number of fungal species colonizing thermal and acoustic fiberglass insulations used in heating, ventilation, and air conditioning (HVAC) systems was fewer than that obtained from initial direct culture of these insulations. The colonization, determined by the microscopic observation of conidiophores with conidia, was primarily of acrylic-latex-facing material, but eventually the fungi permeated the fiberglass matrix. Isolates ofAspergillus versicolor were most often obtained from non-challenged insulation, whereasAcremonium obclavatum appeared to be the primary colonizing fungus in high-humidity (>90%) challenge chambers. At a lower humidity (about 70%)Aspergillus flavus was one of the more prominent fungi. Not all duct liner samples were equally susceptible to colonization and duct board appeared relatively resistant to colonization.     

Fungal colonization of air filters for use in heating,ventilating, and air conditioning (HVAC) systems

Summary New and used cellulosic air filters for HVAC systems including those treated with antimicrobials were suspended in vessels with a range of relative humidities (55–99%) and containing non-sterile potting soil which stimulates fungal growth. Most filters yielded fungi prior to suspension in the chambers but only two of 14 nontreated filters demonstrated fungal colonization following use in HVAC systems. Filters treated with antimicrobials, particularly a phosphated amine complex, demonstrated markedly less fungal colonization than nontreated filters. In comparison with nontreated cellulosic filters, fungal colonization of antimicrobial-treated cellulosic filters was selective and delayed.     

Colonization byCladosporium spp. of painted metal surfaces associated with heating and air conditioning systems

Summary Cladosporium cladosporioides andC. hebarum colonized painted metal surfaces of covering panels and register vents of heating, air conditioning and ventilation systems. Hyphae penetrated the paint film and developed characteristic conidiophores and conidia. The colonies were tightly appressed to the metal surface and conidia were not readily detectable via standard air sampling procedures.     

Cool birds: facultative use by an introduced species of mechanical air conditioning systems during extremely hot outdoor conditions

Rapid climate change across the globe is having dramatic effects on wildlife. Responses of organisms to shifting thermal conditions often include physiological and behavioural accommodations, but to date these have been largely viewed and studied as naturally evolved phenomena (e.g. heat avoidance, sweating, panting) and not necessarily as strategies where animals exploit other anthropogenic conditions or resources. Moreover, the degree to which native versus introduced species show thermal plasticity has generated much conservation and ecological interest. We previously have observed introduced rosy-faced lovebirds (Agapornis roseicollis) perching in the relief-air vents on building faces in the Phoenix, Arizona, USA, metropolitan area, but doing so only during summer. Here, we show that such vent-perching events are significantly associated with extreme outdoor summer temperatures (when daily local highs routinely exceed 40°C). In fact, the temperature threshold at which we detected lovebirds starting to perch in cool air vents mirrors the upper range of the thermoneutral zone for this species. These results implicate novel, facultative use of an anthropogenic resource—industrial air-conditioning systems—by a recently introduced species (within the last 35 years) to cool down and survive extremely hot conditions in this urban ‘heat-island'' environment.     

Dimethyl sulfide emission behavior from landfill site with air and water control

Municipal solid waste landfills are responsible for odors affecting the environment and human health. Dimethyl sulfide (DMS) is one of the major odorous compounds known for its low odor threshold and wide distribution. This study examined the generation, migration and emission of DMS in four artificial landfill-simulating reactors: Reactor 1 and Reactor 2, running under anaerobic and semi-aerobic conditions, respectively, without leachate recirculation; and Reactor 3 and Reactor 4, running under anaerobic and semi-aerobic conditions, respectively, with leachate recirculation. From the odor control perspective, aeration can efficiently inhibit maximum DMS headspace concentration by 31.7–93.7%, especially with the functioning of leachate recirculation. However, leachate recirculation in anaerobic conditions may double the DMS emission concentration but may also shorten the period over which DMS is effective because of the upward migration of liquid DMS in the recirculated leachate. The DMS generation was active in the acidification and methane fermentation phase of the simulated landfill and was possibly affected by the volatile fatty acid concentration, chemical oxygen demand, total organic carbon concentration and pH of the leachate, as well as total organic carbon in the refuse. Most significantly, DMS emission can be effectually dealt with by aeration along with leachate recirculation.     

The inactivation and removal of airborne Bacillus atrophaeus endospores from air circulation systems using UVC and HEPA filters

Aims: To (i) evaluate the UV radiation in the ‘C’ band/high efficient particulate air (UVC/HEPA) instrument’s potential to inactivate spores of Bacillus atrophaeus and selected Bacillus species and (ii) test whether a titanium dioxide coating inside the cylindrical HEPA filter improves the system's efficacy. Methods and Results: Known amounts of dried spore preparations of B. atrophaeus, Bacillus cereus, Bacillus megaterium, Bacillus stearothermophilus and Bacillus thuringiensis were exposed to the UVC lamp within a cylindrical HEPA filter for different time lengths (30 min to 48 h) and with different air flow speeds (0–235 l s^?1). The log₁₀ reduction (range 5–16 logs) of colony forming units for spores exposed to the UVC compared with the unexposed spores was significant (P < 0·0001). The addition of a titanium dioxide (TiO₂) veneer to the interior surface of the HEPA filter significantly increased the inactivation of spores (P < 0·0001). Conclusions: The UVC/HEPA unit could inactivate spores of B. atrophaeus, B. cereus, B. megaterium, B. stearothermophilus and B. thuringiensis. Significance and Impact of the Study: The UVC/HEPA unit represents an effective method of decontaminating circulating air within an air‐duct system as found in a building.     

应用DNDC模型分析施肥和翻耕方式变化对旱田土壤N_2O释放的潜在影响

以贵州省玉米 油菜轮作田和大豆 冬小麦轮作田为N2 O释放通量测量对象 ,根据DNDC模型能较好地拟合田间N2 O释放通量季节变化及施肥和翻耕对释放的影响 ,采用DNDC模型定量探讨了上述作物生长季节有机肥施用量、N肥施用量及施肥日期、N肥类型和施肥深度、翻耕深度和翻耕日期等变化对亚热带旱田生态系统N2 O释放的潜在影响 .为今后通过改变施肥和耕作方式来控制农业土壤N2 O释放量提供研究基础和参考 .     

应用DNDC模型分析施肥和翻耕方式变化对旱田土壤N2O释放的潜在影响

以贵州省玉米-油菜轮作田和大豆-冬小麦轮作田为N₂O释放通量测量对象,根据DNDC模型能较好地拟合田间N₂O释放通量季节变化及施肥和翻耕对释放的影响,采用DNDC模型定量探讨了上述作物生长季节有机肥施用量、N肥施用量及施肥日期、N肥类型和施肥深度、翻耕深度和翻耕日期等变化对亚热带旱田生态系统N₂O释放的潜在影响.为今后通过改变施肥和耕作方式来控制农业土壤N₂O释放量提供研究基础和参考.     

应用DNDC模型分析施肥和翻耕方式变化对旱田土壤N2O释放的潜在影响

以贵州省玉米－油菜轮作田和大豆－冬小麦轮作田为N2O释放通量测量对象,根据DNDC模型能较好地拟合田间N2O释放通量季节变化及施肥和翻耕对释放的影响,采用DNDC模型定量探讨了上述作物生长季节有机肥施用量、N肥施用量及施肥日期、N肥类型和施肥深度、翻耕深度和翻耕日期等变化对亚热带旱田生态系统N2O释放的潜在影响,为今后通过改变施肥和耕作方式来控制农业土壤N2O释放量提供研究基础和参考。     

Hydrogen sulphide removal from air by biotrickling filter using open-pore polyurethane foam as a carrier

A study was conducted on H₂S removal in a biotrickling filter packed with open-pore polyurethane foam. Thiobacillus denitrificans was used as inoculum and a mixed culture population was developed during the process. The inhibitory effect of sulphate concentration (1.8–16.8 g L⁻¹), pH (6.9–8.6), trickling liquid velocity (TLV, 9.1–22.8 m h⁻¹), H₂S inlet concentration (20–157 ppmv) and the empty bed residence time (EBRT, 9–57 s) on the H₂S removal efficiency (RE) were thoroughly investigated. An increase in pH from 6.9 to 8.5 led to a corresponding increase in H₂S removal. In addition, an inhibitory effect of sulphate concentration was observed from 16.8 g L⁻¹ and the maximum elimination capacity was found to be 22 gS m⁻³ h⁻¹ (RE 98%). The RE was constant (98.8 ± 0.30%) for EBRT ≥ 16 s, but a decrease in the EBRT from 16 to 9 s led to a corresponding decrease in RE from 98.2 to 89.6% for a TLV of 9.1 m h⁻¹ and from 97.9 to 94.9% for a TLV of 22.8 m h⁻¹ (inlet load of 11.0 ± 0.2 gS m⁻³ h⁻¹). The sulphur oxidation capacity in the biotrickling filter was not diminished by the presence of other bacteria.     

Ethanol production from glucose and xylose by separated and co-culture processes using high cell density systems

Media containing xylose and/or glucose were tested utilizing Zymomonas mobilis or Saccharomyces diastaticus and Pichia stipitis. The best fermentation results were obtained in separated glucose (180 g/litre) and xylose (80 g/litre) fermentations utilizing Zymomonas mobilis and Pichia stipitis strains, respectively. In these conditions, the maximum ethanol concentrations achieved were 86·2 g/litre and 29 g/litre, respectively. The complete conversion of a glucose and xylose mixture (50 g/litre) was obtained using a respiratory deficient mutant of Saccharomyces diastaticus co-cultivated with Pichia stipitis in continuous culture. Using the co-culture process, the maximum ethanol concentration was 21·5 g/litre (Yp/s=0·45 g/g) and the maximum volumetric ethanol productivity was 4·3 g/(litre × h).     

Lily breeding by using molecular tools and transformation systems

In our review, we highlighted the progresses made in molecular breeding of lily’s flowering, including the ABCDE models, the gene cloning, the establishment of regeneration system, the gene transformation methods, the transgene technology application in lily. Meanwhile, questions that were met at present in molecular breeding in flowering of lily were underlined, and we provide viable solutions. Although many researches on lily literature had been published in the world, in our review, we provided a valuable and unique resource and spring-board from which to understand or further study the molecular breeding in flowering of lily.     

Elimination of keratin artifact bands from western blots by using low concentrations of reducing agents

We encountered β-mercaptoethanol-dependent artifact signals in western blot analyses using polyclonal antisera. Replacing β-mercaptoethanol with dithiothreitol in the loading buffer did not eliminate the artifact signals. However, lowering the concentration of either dithiothreitol or β-mercaptoethanol eliminated the background problems and allowed specific detection of the target protein. These results are consistent with the background signal being caused by anti-keratin antibodies in the antisera and keratin contamination of reagents. This study highlights the importance of testing a range of reducing agent concentrations when trying to eliminate artifact bands from western blots. However, this method may not be applicable when target proteins have disulfide bridges.     

Study and formation of vesicle systems with low polydispersity index by ultrasound method

The formation of liposomes with low polydispersity index by application of ultrasounds was investigated considering methodology specifications such as sonication time and sonication power. Phosphatidylcholine (PC) liposomes were formed by the evaporation–hydration method. The vesicles were sonicated using several sonication conditions. The liposomes were then characterized by dynamic light scattering (DLS) and freeze-fracture electron microscopy (FFEM). Correlation functions from DLS were treated by cumulants method and GENDIST to obtain the mean radius and polydispersity index. These calculations allowed to fix an optimal sonication time (3000 s) and a useful interval of ultrasound power between 39 and 91 W. DLS and FFEM results confirmed that vesicle size, lamellarity and the polydispersity index decreased with the increase of sonication power. Thus, we propose a systematic method to form liposomes in which the physical characteristics of the vesicles may be controlled as a function of sonication time and power.     

应用微生物与秸秆降低鸡粪氨气释放量

为减轻大量禽畜废弃物中氨气流失对环境的污染,研究和优化了微生物与秸秆等辅料对氨气释放量的影响。结果表明,F468、M1?M9等除臭微生物能显著降低氨气的释放量,其中F468是最优微生物,其它微生物与F468的配伍并没有显著增强F468降低氨气释放量的能力,有些微生物还降低了其能力,因此选择单一微生物法降低氨气释放量。单独添加辅料对降低氨气的释放影响较小,辅料与微生物的配伍可大量降低氨气的释放量。5%的F468与10%的秸秆配伍在1?5 d降低88%的释放量。应用微生物与秸秆不仅降低氨气挥发对环境的危害,也是秸秆资源化利用的有效途径之一。     

Effect of the microbial conditioning and temperature increase on the leaf consumption by shredders in Amazonian aquatic systems

Hydrobiologia - We used experimental chambers to evaluate the effect of the temperature increasing and microbial conditioning degree on the survival and leaf consumption of two plant species...