Product Guide/1979

The Product Guide series which appears in the Journal of the Air Pollution Control Association and the APCA Directory and Resource Book is a computer-based program. A questionnaire form provided entry into the program for responding manufacturers of emission control equipment and air pollution instrumentation. If any manufacturers or product categories have been overlooked, the omission is regretted and should be brought to the attention of the editor, JAPCA.     

Dynamics of dust explosions suppression by means of extinguishing powder in various industrial conditions

In industrial conditions, there are different kinds of installations endangered by an explosion of dust–gas mixtures. In order to prevent them from any consequences of potential explosions, active protection systems which use extinguishing powders, as the suppressing material, are more and more widely applied. It often happens that the industrial installations are additionally endangered by an action of mechanical vibrations. In the above-mentioned conditions, the extinguishing powder tends to aggregate, making the process of dispersing it in the protected areas more difficult.

The results of research into optimization of the shape, number of igniters and miniaturization of the explosive charge mass are presented. In case of occurrence of the mechanical vibrations in the installations that cause aggregation of the suppressing powder, the best solution was modification of the perforated combustion chamber located inside the extinguisher. As a result of that, a certain amount of gases generated in the course of combustion of the main charge is directed over the membrane, where the gases crash a layer of aggregated powder. Thus, the process of pushing the powder out from a container towards the dispersing head improves considerably and consequently increases the efficiency of the explosion-suppressing process.     

Occurrences and potential risks of 16 fragrances in five German sewage treatment plants and their receiving waters

Fragrances are used in a wide array of everyday products and enter the aquatic environment via wastewater. While several musk compounds have been studied in detail, little is known about the occurrence and fate of other fragrances. We selected 16 fragrance compounds and scrutinized their presence in Bavarian sewage treatment plants (STP) influents and effluents and discussed their ecological risks for the receiving surface waters. Moreover, we followed their concentrations along the path in one STP by corresponding time-related water sampling and derived the respective elimination rates in the purification process. Six fragrance substances (OTNE, HHCB, lilial, acetyl cedrene, menthol, and, in some grab samples, also methyl-dihydrojasmonate) could be detected in the effluents of the investigated sewage treatment plants. The other fragrances under scrutiny were only found in the inflow and were eliminated in the purification process. Only OTNE and HHCB were found in the receiving surface waters of the STP in congruent concentrations, which exceeded the preliminary derived environmental thresholds by a factor of 1.15 and 1.12, respectively, indicating potential risks. OTNE was also detected in similar concentration ranges as HHCB in muscles and livers of fish from surface waters and from ponds that are supplied with purified wastewater. The findings show that some fragrance compounds undergo high elimination rates, whereas others—not only musks—are present in receiving surface water and biota and may present a risk to local aquatic biota. Hence, our results suggest that the fate and potential effects of fragrance compounds in the aquatic environment deserve more attention.     

Adolescent social environment shapes sexual and aggressive behaviour of adult male zebra finches (Taeniopygia guttata)

Adolescence is the pivotal transitional phase during which animals become sexually and socially mature and acquire the skills to cope with a variety of environmental challenges on their own. We investigated in a bird species, the zebra finch, how the social environment experienced during this period influences their behaviour in a sexual context. Zebra finches were kept in pairs (male–female or male–male) or larger mixed-sex groups (three males and three females) during adolescence and the long-term consequences were studied on courtship behaviour, aggressiveness and attractiveness in 42 males. To investigate the stability of the observed effects over time, all behavioural tests were repeated approximately 4 months after the initial recordings. Males that grew up with a single female showed the most intense courtship and highest aggressiveness and were most attractive to females, while group-reared males had the lowest courtship and aggressiveness and were the least attractive. The observed differences in courtship and aggressiveness were stable, while the differences in attractiveness disappeared over time. These findings are very similar to earlier studies on guinea pigs, indicating that the observed effects represent a general phenomenon, not restricted to mammals with a similar function and presumably also similar underlying mechanisms.     

Effects of Artificial Roosts for Frugivorous Bats on Seed Dispersal in a Neotropical Forest Pasture Mosaic

Abstract:  In the Neotropics ongoing deforestation is producing open and heavily fragmented landscapes dominated by agriculture, mostly plantations and cattle pastures. After some time agriculture often becomes uneconomical and land is abandoned. Subsequent habitat regeneration may be slow because seed inputs are restricted by a lack of incentives—such as suitable roost sites—for seed dispersers to enter deforested areas. Increasing environmental awareness has fostered growing efforts to promote reforestation. Practical and cost-efficient methods for kick-starting forest regeneration are, however, lacking. We investigated whether artificial bat roosts for frugivorous bat species can attract these key seed dispersers to deforested areas, thereby increasing seed rain. We installed artificial bat roosts in a forest-pasture mosaic in the Costa Rican Atlantic lowlands and monitored bat colonization and seed dispersal. Colonization occurred within a few weeks of installation, and 10 species of bats occupied the artificial roosts. Five species of frugivorous or nectarivorous bats colonized artificial roosts permanently in both primary habitat and in deforested areas, in numbers similar to those found in natural roosts. Seed input around artificial roosts increased significantly. Sixty-nine different seed types, mostly of early-successional plant species, were transported by bats to artificial roosts in disturbed habitats. The installation of artificial bat roosts thus successfully attracted frugivorous bats and increased seed inputs into degraded sites. This method is likely to speed up early-vegetation succession, which in turn will attract additional seed dispersers, such as birds, and provide a microhabitat for seeds of mid- and late-successional plants. As well as supporting natural forest regeneration and bat conservation, this cost-efficient method can also increase environmental awareness among landowners.     

Storm surges: perspectives and options

This review paper attempts to summarize the scattered and fragmented knowledge about past and possible future changing storm-surge statistics using the particularly well-studied case of the North Sea as an example. For this region, a complete and robust analysis methodology has been developed in recent years. This methodology is based on dynamical and statistical models. Using the concept of dynamical downscaling, development during recent decades, when sufficiently good and homogeneous weather data exist, has been “reconstructed,” and scenarios of possible future change are described. “Localization” allows estimation of changes at specific sites, e.g., harbors. As local water-level statistics depend not only on climate variations but also on local modifications of the local bathymetry, new options for adaptation emerge. For the case of Hamburg, an option for such future adaptations is discussed.     

Concentrations and sources of carbonaceous aerosol in the atmosphere of Summit,Greenland

High-volume PM_2.5 samples were collected at Summit, Greenland for approximately six months from late May through December of 2006. Filters were composited and analyzed for source tracer compounds. The individual organic compounds measured at Summit are orders of magnitude smaller than concentrations measured at other sites, including locations representative of remote oceanic, and remote and urban continental aerosol. The measured tracers were used to quantify the contribution of biomass burning (0.6–0.9 ng C m^?3), vegetative detritus (0.3–0.9 ng C m^?3), and fossil fuel combustion (0.1–0.8 ng C m^?3) sources, 4% of OC total, to atmospheric organic carbon concentrations at the remote location of Summit, Greenland. The unapportioned organic carbon (96%) during the early summer period correlates well with the fraction of water soluble organic carbon, indicating secondary organic aerosol as a large source of organic carbon, supported by the active photochemistry occurring at Summit. To the author's knowledge, this paper represents the first source apportionment results for the polar free troposphere.