Comparison of odour emission rates measured from various sources using two sampling devices

Two commonly used sampling devices (a wind tunnel and the US EPA dynamic emission chamber), were used to collect paired samples of odorous air from a number of agricultural odour sources. The odour samples were assessed using triangular, forced-choice dynamic olfactometry. The odour concentration data was combined with the flushing rate data to calculate odour emission rates for both devices on all sources. Odour concentrations were consistently higher in samples collected with a flux chamber (ratio ranging from 10:7 to 5:1, relative to wind tunnel samples), whereas odour emission rates were consistently larger when derived from wind tunnels (ratio ranging from 60:1 to 240:1, relative to flux chamber values). A complex relationship existed between emission rate estimates derived from each device, apparently influenced by the nature of the emitting surface. These results have great significance for users of odour dispersion models, for which an odour emission rate is a key input parameter.     

Odour sampling. 2. Comparison of physical and aerodynamic characteristics of sampling devices: a review

Sampling devices differing greatly in shape, size and operating condition have been used to collect air samples to determine rates of emission of volatile substances, including odour. However, physical chemistry principles, in particular the partitioning of volatile substances between two phases as explained by Henrys Law and the relationship between wind velocity and emission rate, suggests that different devices cannot be expected to provide equivalent emission rate estimates. Thus several problems are associated with the use of static and dynamic emission chambers, but the more turbulent devices such as wind tunnels do not appear to be subject to these problems. In general, the ability to relate emission rate estimates obtained from wind tunnel measurements to those derived from device-independent techniques supports the use of wind tunnels to determine emission rates that can be used as input data for dispersion models.     

Odour emissions from anaerobic piggery ponds. 2: improving estimates of emission rate through recognition of spatial variability

Odour emission rates were measured for seven different anaerobic ponds treating piggery wastes at six to nine discrete locations across the surface of each pond on each sampling occasion over a thirteen month period. Significant variability in emission rates were observed for each pond. Measurement of a number of water quality variables in pond liquor samples collected at the same time and from the same locations as the odour samples indicated that the composition of the pond liquor was also variable. The results indicated that spatial variability was a real phenomenon and could have a significant impact on odour assessment practices. Considerably more odour samples would be required to characterise pond emissions than currently recommended by most practitioners, or regulatory agencies.     

Assessment of permeable covers for odour reduction in piggery effluent ponds. 1. Laboratory-scale trials

A variety of materials were trialed as supported permeable covers using a series of laboratory-scale anaerobic digesters. Efficacy of cover performance was assessed in terms of impact on odour and greenhouse gas emission rate, and the characteristics of anaerobic liquor. Data were collected over a 12-month period. Initially the covers reduced the rate of odour emission 40-100 times relative to uncovered digesters. After about three months, this decreased to about a threefold reduction in odour emission rate, which was maintained over the remainder of the trial. The covers did not alter methane emission rates. Carbon dioxide emission rates varied according to cover type. Performance of the covers was attributed to the physical characteristics of the cover materials and changes in liquor composition. The reductions in odour emission indicate that these covers offer a cost-effective method for odour control.     

Odour and ammonia emissions from intensive poultry units in Ireland

Odour and ammonia emissions were measured from three broiler, two layer and two turkey houses in Ireland. The broiler units gave a large range of odour and ammonia emission rates depending on the age of the birds and the season. A considerable variation between the odour and ammonia emission rates was evident for the two layer units which may have been due to the different manure handling systems utilised in the houses. There was relatively little difference in the odour and ammonia emissions from the two turkey houses. As a precautionary principle, odour emission rates utilised in atmospheric dispersion models should use the maximum values for broilers and turkeys (1.22 and 10.5 ou(E) s(-1) bird(-1) respectively) and the mean value for the layers depending on the manure handling system used (0.47 or 1.35 ou(E) s(-1) bird(-1)).     

Long-term assessment of efficacy of permeable pond covers for odour reduction

Three anaerobic ponds used to store and treat piggery wastes were fully covered with permeable materials manufactured from polypropylene geofabric, polyethylene shade cloth and supported straw. The covers were assessed in terms of efficacy in reducing odour emission rates over a 40-month period. Odour samples were collected from the surface of the covers, the surface of the exposed liquor and from the surface of an uncovered (control) pond at one of the piggeries. Relative to the emission rate of the exposed liquor at each pond, the polypropylene, shade cloth and straw covers reduced average emission rates by 76%, 69% and 66%, respectively. At the piggery with an uncovered control pond, the polypropylene covers reduced average odour emission rates by 50% and 41%, respectively. A plausible hypothesis, consistent with likely mechanisms for the odour reduction and the olfactometric method used to quantifying the efficacy of the covers, is offered.     

Odour and ammonia emissions from intensive pig units in Ireland

Odour and ammonia emissions were measured at four intensive pig units in Ireland. Odour samples were collected on-site and analysed for odour concentration using an olfactometer. Ammonia concentrations in the exhaust ventilation air were measured using a portable sensor. The geomean odour emission rates over the four pig units were 17.2, 44.4, 4.3, 9.9 and 16.8 ou(E) s(-1) animal(-1) for dry sows, farrowing sows, first stage weaners, second stage weaners and finishers, respectively. The mean ammonia emission rates, measured at two of the units, were 12.1, 17.1, 1.4, 2.9 and 10.0 g d(-1) animal(-1) for dry sows, farrowing sows, first stage weaners, second stage weaners and finishers, respectively. In general, the odour and ammonia emission rates were comparable to those reported in literature, although some odour emission rate figures were noticeably lower for finishing pigs in this study. The variability in the data highlights the need for individual site assessment.     

Evaluation of sampling methods for determining infestation rates of the tracheal mite (Acarapis woodi R.) in colonies of the honey bee (Apis mellifera): Spatial,temporal, and spatio-temporal effects

Current sampling methods for estimating infestation rates of tracheal mites in colonies of the honey bee,Apis mellifera, assume that infested bees are randomly distributed and that temporal fluctuations in infestation rates occur homogeneously throughout the colony. We examined these assumptions. Samples of bees were collected from up to five locations in each of eight colonies, and colonies were sampled several times throughout the year. Estimates of infestation rates varied, depending on the location in the colony from which a sample was obtained. Temporal fluctuations in infestation rates did not always occur homogeneously with respect to sampling location. These results demonstrate that assumptions of current sampling protocols for estimating tracheal-mite infestation rates are often violated. Consequently, estimates derived using these methods may not be accurate, and conclusions based on such estimates may not be valid.     

Electroantennogram responses of tsetse flies (Glossina pallidipes) to host odours in an open field and riverine woodland

The present study was initiated to gain insight into the way in which tsetse flies ( Glossina spp.) sense odours at different locations in odour plumes in both an open field and a wooded area.
We recorded the antennal responses (EAGs) from stationary living female G. pallidipes 15 m upwind and at various (60, 40, 20, 10, 5 and 1 m) distances downwind from a synthetic host odour source (containing 1-octen-3-ol, acetone and two phenols), in the natural habitat of the fly (Zimbabwe) using a portable electrophysiological device. Experiments were performed in a flat open area (an airstrip) and in riverine woodland. Differences between responses in different environments were determined by comparing various parameters of the EAGs (intermittency, frequency, amplitude, duration and rate of depolarization).
We found that a fly senses odours as puffs that, further downwind, contain less odour and pass less frequently. In an open field downwind from the source, tsetse perceive more olfactory information than upwind for only 10–20 m, whereas in woodland, olfactory responses remain higher and more frequent than upwind up to at least 60 m. In an open field, olfactory information rapidly increases when approaching the odour source from 20 m and in woodland from 5 m onwards.
It is proposed that averaging odour information over time may be of minor importance in long-range location of odour sources. The results suggest that tsetse may smell odour-baited targets from at least 60 m downwind and that the number of flies responding to and being caught by these baits may be higher in woodland than in an open field.     

Assessment of permeable covers for odour reduction in piggery effluent ponds. 2. Field-scale trials

The efficacy of supported covers was investigated under field conditions using a series of prototypes deployed on an anaerobic pond treating typical piggery waste. Research focused on identifying effective cover support materials and deployment methods, quantifying odour reduction, and estimating the life expectancy of various permeable cover materials. Over a 10-month period, median odour emission rates were five to eight times lower from supported straw cover surfaces and a non-woven, spun fibre polypropylene weed control material than from the adjacent uncovered pond surface. While the straw covers visually appeared to degrade very rapidly, they continued to reduce odour emissions effectively. The polypropylene cover appeared to offer advantages from the perspectives of cost, reduced maintenance and ease of manufacture.     

Comparison of human axillary odour profiles obtained by gas chromatography/mass spectrometry and skin microbial profiles obtained by denaturing gradient gel electrophoresis using multivariate pattern recognition

Several studies have shown that microbial action is responsible for many compounds responsible for human odour. In this paper, we compare the pattern of microbial profiles and that of chemical profiles of human axillary odour by using multivariate pattern matching techniques. Approximately 200 subjects from Carinthia, Austria, participated in the study. The microbial profiles were represented by denaturing gradient gel electrophoresis (DGGE) analysis and the axillary odour profiles were determined in the sweat samples collected by a stir-bar sampling device and analysed by gas chromatography/mass spectrometry (GC/MS). Both qualitative and quantitative distance metrics were used to construct dissimilarity matrices between samples which were then used to represent the patterns of these two types of profiles. The distance matrices were then compared by using the Mantel test and the Procrustean test. The results show that on the overall dataset there is no strong correlation between microbial and chemical profiles. When the data are split into family groups, correlations vary according to family with a range of estimated p values from 0.00 to 0.90 that the null hypothesis (no correlation) holds. When 32 subjects who followed four basic rules of behaviour were selected, the estimated p-values are 0.00 using qualitative and <0.01 using quantitative distance metrics, suggesting excellent evidence that there is a connection between the microbial and chemical signature.     

The influence of diet crude protein level on odour and ammonia emissions from finishing pig houses

Feed trials were carried out to assess the influence of crude protein content in finishing pig diets on odour and ammonia emissions. Eight pigs (4 boars and 4 gilts), average initial weight 70.8 kg (s.e. 3.167) were housed in two pens that were isolated from the rest of a pig house at University College Dublin Research Farm, Newcastle, Dublin, Ireland. Four diets containing 130, 160, 190 and 220 g x kg(-1) crude protein were fed during six four-week feeding periods (one treatment per room). The first week of the feeding periods served to allow odour build up in the pens and as a dietary adjustment period. The pens had partially slatted floors that were cleaned and had all the manure removed after each four-week period. Odour and ammonia concentrations were measured on days 9, 14, 16, 21 and 23 of each trial period. Odour samples were collected in Nalophan bags and analysed for odour concentration using an ECOMA Yes/No olfactometer. The odour threshold concentration was calculated according to the response of the olfactometry panel members and was displayed in Ou(E)m(-3), which referred to the physiological response from the panel equivalent to that elicited by 40 ppbv(-1) n-butanol evaporated in 1 m(3) of neutral gas. Ammonia concentrations in the ventilation air were measured using Dr?ger tubes. The odour emission rates per animal for the 130, 160, 190 and 220 g x kg(-1) crude protein diets were 12.1, 13.2, 19.6 and 17.6 Ou(E)s(-1)animal(-1), respectively (P<0.01). The odour emission rate per livestock unit (500 kg) for the 130, 160, 190 and 220 g x kg(-1) crude protein diets were 77.6, 80.0, 115.8 and 102.9 Ou(E)s(-1)LU(-1), respectively (P<0.01). The ammonia emission rates per animal for the 130, 160, 190 and 220 g x kg(-1) crude protein diets were 3.11, 3.89, 5.89 and 8.27 g x d(-1)animal(-1), respectively (P0.05). Manipulation of dietary crude protein levels would appear to offer a low cost alternative, in relation to end-of-pipe treatments, for the abatement of odour and ammonia emissions from finishing pig houses.     

The use of pine bark and natural zeolite as biofilter media to remove animal rendering process odours

Studies of odour-control pilot-scale biofilters at a rendering plant were conducted for five years. The biofilters contained different sizes of crushed pine bark or a mixture of zeolite and crushed bark, and treated the exhaust gases from direct-fired meal dryers. The exhaust gases were odorous and contained significant smoke. The odour concentration of the rendering process air ranged between 50,000 and 307,200 OU m(-3). Odour-removal performance measurements of the biofilters were undertaken on five occasions using forced-choice dynamic-dilution olfactometry. Biofilter odour-removal efficiencies of between 80% and 99% were measured at various influent odour concentrations and air loading rates. There was no obvious deterioration in performance of these biofilters between various sampling times in the five year study period. The biofilters also reduced the "offensiveness" of the odour. The fine crushed bark biofilter generally reduced odour concentration more efficiently than the coarse bark biofilter. The additions of zeolite to the bark medium in the biofilter had little effect on the odour-removal performance. An increase in air loading rate produced only a very small decrease in odour-removal performance. The pilot-scale biofilters had smoke removal efficiencies between 71% and 100%. Finely crushed bark removed smoke more effectively than coarsely crushed bark. Drainage from the biofilters contained significant concentrations of pollutants, suggesting that controlled leaching has potential to remove accumulated substances in biofilter media from rendering gas emissions and increase the longevity of a biofilter system.     

The excitation mechanism of btp2Ir(acac) in CBP host

Whether bis(2‐(2′‐benzo[4,5‐α]thienyl)pyridinato‐N,C3′)iridium(acetylacetonate) (btp₂Ir(acac)) emission comes from carrier trapping and/or energy transfer, when doped in the 4,4′‐bis(N‐carbazolyl)biphenyl (CBP) host in organic light‐emitting devices, is not clear; therefore, the btp₂Ir(acac) emission in CBP hosts was studied. In the red‐doped device, both N,N′‐bis(1‐naphthyl)‐N,N′‐diphenyl‐1.1′‐bipheny1–4‐4′‐diamine (NPB) and (1,1′‐biphenyl‐4′‐oxy)bis(8‐hydroxy‐2‐methylquinolinato)‐aluminum (BAlq) emission appeared, which illustrated that CBP excitons cannot be formed at two emissive layer (EML) interfaces in the device. In the co‐doped devices, NPB and BAlq emissions disappear and 1,4‐bis[2‐(3‐N‐ethylcarbazoryl)vinyl]benzene (BCzVB) emission appears, illustrating the formation of CBP excitons at two EML interfaces in these devices. The reason for this difference was analyzed and it was found that holes in the NPB layer could be made directly into the CBP host in the EML interface of the red‐doped device. In contrast, holes were injected into CBP host via the btp₂Ir(acac)/BCzVB dopants in the co‐doped devices, which facilitated hole injection from the NPB layer to the EML, leading to the formation of CBP excitons at two EML interfaces in the co‐doped devices. Therefore, btp₂Ir(acac) emission was caused by carrier trapping in the red‐doped device, while, in the co‐doped devices, it resulted from both carrier trapping and energy transfer from the CBP. Furthermore, it was revealed that the carrier trapping mechanism is less efficient than the energy transfer mechanism for btp₂Ir(acac) excitation in co‐doped devices. In summary, our results clarified the excitation mechanism of btp₂Ir(acac) in the CBP host.     

Ecology of fishes in a high-latitude,turbid river with implications for the impacts of hydrokinetic devices

Hydrokinetic devices generate electricity by capturing kinetic energy from flowing water as it moves across or through a rotor, without impounding or diverting the water source. The Tanana River in Alaska, a turbid glacial system, has been selected as a pilot location to evaluate the effects of such a device on fish communities that are highly valued by subsistence, sport, and commercial users. The basic ecology and habitat use of fishes in turbid glacial systems are poorly understood; therefore it is necessary to study the species composition of the fish community and the spatial and temporal patterns of mainstem river use by these fishes to evaluate impacts of a hydrokinetic device. In this document, we provide an overview of existing knowledge of fish ecology in the Tanana River and impacts of hydrokinetic devices on fishes in other river systems. Seventeen fish species are known to inhabit the Tanana River and several may utilize the deepest and fastest section of the channel, the probable deployment location for the hydrokinetic device, as a seasonal migration corridor. Previous studies in clearwater river systems indicate that mortality and injury rates from turbine passage are low. However, the results from these studies may not apply to the Tanana River because of its distinctive physical properties. To rectify this shortcoming, a conceptual framework for a comprehensive fish ecology study is recommended to determine the impacts of hydrokinetic devices on fishes in turbid, glacial rivers.     

First steps in robot automation of sampling and sample management during cultivation of mammalian cells in pilot scale

The robot automation of sampling and the subsequent treatment and storage of aliquots during mammalian cell cultivations was investigated. The complete setup, the development and testing of the sampling device, the robot arm, and the cell imaging system are described. The developed sampling device is directly coupled to a pilot bioreactor. It allows the computerized sterile filling of cell broth into 50 mL sample tubes. After each sampling the whole tubing system is steam sterilized. For further off-line treatment a robot takes the sample to the different devices. This robot is equipped with a camera and a force/torque sensor. A color-based object recognition guides the arm in a complex surrounding with different illumination situations, enabling the robot to load the sampling device with tubes and take the sample to further devices. For necessary pipetting and refilling we developed a computerized device. Cells are automatically stained and counted using an imaging system. The cell number and viability is automatically saved in a process control system together with the on-line parameters. During several cultivations in 20 and 100 L scale these main components of the automation strategy were successfully tested.     

Integration of a surface acoustic wave biosensor in a microfluidic polymer chip

SAW devices based on horizontally polarized surface shear waves (HPSSW) enable label-free, sensitive and cost-effective detection of biomolecules in real time. It is known that small sampling volumes with low inner surface areas and minimal mechanical stress arising from sealing elements of miniaturized sampling chambers are important in this field. Here, we present a new approach to integrate SAW devices with sampling chamber. The sensor device is encapsulated within a polymer chip containing fluid channel and contact points for fluidic and electric connections. The chip volume is only 0.9 microl. The polymeric encapsulation was performed tailor-made by Rapid Micro Product Development 3Dimensional Chip-Size-Packaging (RMPD 3D-CSP), a 3D photopolymerisation process. The polymer housing serves as tight and durable package for HPSSW biosensors and allows the use of the complete chips as disposables. Preliminary experiments with these microfluidic chips are shown to characterise the performance for their future applications as generic bioanalytical micro devices.     

Floral odour and reproductive isolation in two species of Silene

Mechanisms preventing interspecific pollination are important in closely related plant species, in particular when post-zygotic barriers are weak or absent. We investigated the role of floral odour in reproductive isolation between the two closely related species Silene latifolia and S. dioica. First, we tested whether floral odour composition and emission differed between the species. We found significant odour differences, but contrary to expectations, both species showed a rhythmic emission of the same compounds between day and night. Second, in a field experiment, odour of the two species was made more similar by applying phenylacetaldehyde to flowers. This manipulation led to higher pollen-analogue transfer between species, revealing that floral odour differences are important for maintaining reproductive isolation. We conclude that differences in single key compounds can reduce pollen transfer across species boundaries by pollinators and demonstrate that odour differences are an important component of premating floral isolation between closely related plant species.     

Comparison of benthic macroinvertebrate communities by two methods: Kick- and U-net sampling

The assessment of benthic invertebrate community condition is an integral component of freshwater biomonitoring and water quality determination. Several sampling devices have been developed to collect benthic macroinvertebrates, including qualitative, semi-quantitative, and quantitative methods. In this study, we compared several benthic macroinvertebrate metrics and community assemblage measures calculated from data obtained from two sampling methods, namely the Kick- and U-net sampling devices. We reasoned that if the two methods produced similar values for benthic metrics and community composition, then samples collected by these methods should be able to be combined to build larger data sets for use in regional bioassessment analyses. No statistical differences between Kick- and U-net methods were found among standard benthic macroinvertebrate metrics, except for Kick-nets collecting more Chironomidae. Invertebrate assemblages were very similar between collection methods, although slightly greater taxonomic richness was found in U-net samples. Bray–Curtis similarity was typically >75% between methods within a stream, while classification strength-sampling-method comparability, an approach for analyzing differences in similarity between groups, indicated invertebrate assemblage similarity between collection methods was virtually identical at approximately 100%. Since these two methods produce similar results, we conclude that benthic macroinvertebrate data collected by these methods can be combined for data analysis and bioassessments with the caveat that mesh size of the sample nets is similar. In addition, if the primary study objective is to assess macroinvertebrate biodiversity, then the U-net sampling device may be more appropriate, despite the slightly greater time needed to complete field sample collection, as it tended to collect a greater diversity of species.     

Blue light emission spectra of popular mobile devices: The extent of user protection against melatonin suppression by built-in screen technology and light filtering software systems

ABSTRACT

Blue light, with wavelengths shorter than 440–450 nm, is the most energetic radiation of the visible spectrum for the human eye, and its possible multiple effects on the human nervous and other systems have become a line of research by many investigators. The use of mobile devices whose screens emit various amounts of blue light is common nowadays. This study evaluated the efficiency of the blue light screen and control software technologies of eight different mobile devices. Emitted screen spectra of the different mobile devices according to different conditions of blue light emission software control were obtained using a spectrograph, and the derived spectra were compared with the melatonin suppression action spectrum. The amount of blue light emission and predicted melatonin suppression varied according to the unique software control and screen technology of each device. AMOLED screen technology, compared with other screen technologies, achieved better control of blue light emission. The effect of blue light filters depends on the screen technology; however, the melatonin suppression index of mobile devices is not reduced sufficiently by the use of blue light-attenuating software.