THE INFRARED RECEPTIVE FIELDS OF MELANOPHILA ACUMINATA (COLEOPTERA: BUPRESTIDAE)

1980 ◽  
Vol 112 (2) ◽  
pp. 211-216 ◽  
Author(s):  
W. G. Evans ◽  
J. E. Kuster
Keyword(s):  
Forest Fires ◽  
Infrared Radiation ◽  
Solid Angle ◽  
Receptive Fields ◽  
Point Sources ◽  
Melanophila Acuminata

AbstractReceptive fields of the infrared receptors located in sensory pits adjacent to the mesocoxal cavities of Melanophila acuminata were measured using a goniometric apparatus and plotted on a Mollweide homolographic projection. The receptive fields extend mainly in a lateral and ventral direction. The total receptive area in units of solid angle is 5.80 steradians but the simultaneous field of perception of infrared radiation of all the sensilla in a pit is only 0.42 steradian. Based on these findings and on other evidence we believe that the infrared-sensitive sensilla function during flight and are used by these beetles for detecting point sources of heat, such as forest fires, from long distances.

Perception of Infrared Radiation from Forest Fires by Melanophila Acuminata de Geer (Buprestidae, Coleoptera)

Ecology ◽  
1966 ◽  
Vol 47 (6) ◽  
pp. 1061-1065 ◽  
Author(s):  
William G. Evans
Keyword(s):  
Forest Fires ◽  
Infrared Radiation ◽  
Melanophila Acuminata

Broadband Random Phase Diffuser for Ultrasonic Imaging

1979 ◽  
Vol 1 (4) ◽  
pp. 325-332
Author(s):  
Gerard A. Alphonse ◽  
David Vilkomerso
Keyword(s):  
Solid Angle ◽  
Random Phase ◽  
Ultrasonic Imaging ◽  
Standing Waves ◽  
Acoustic Imaging ◽  
Point Sources ◽  
Phase Plate ◽  
Reflected Waves ◽  
Large Aperture ◽  
The Waves

In reflective imaging, waves must be scattered by the object over a broad solid angle so that some of the reflected waves impinge upon the collecting aperture. Surfaces such as biological specimens under study in acoustic imaging are considered smooth at the wavelengths used (e.g., 1 mm) and therefore act as specular reflectors. In order to obtain reflection over a broad spatial range, large aperture, sector or compound scanning are used. In certain types of systems, diffuse insonification is sometimes used by imaging a raster of random phase points onto the surface. However interference between the waves from these point sources produces random fringes or “speckle-like” patterns overlaying the image. In optics these fringes have been reduced by rotating the diffuser. A similar approach has been taken here. This paper describes a simple random phase plate having two levels, 0° and 180 phase that can, by rotation, change the relative phases of the diffuse insonification points so as to reduce the speckle-like effect in the image. The temporal bandwidth of the random phase plate is narrow because of standing waves in it. To reduce standing waves the diffuser is intimately coupled to a wedged transducer. This combination is used to obtain diffuse insonification with broad spatial and temporal bandwidth.

scholarly journals Opportunistic Experiments to Constrain Aerosol Effective Radiative Forcing

2021 ◽  
Author(s):  
Matthew Christensen ◽  
Andrew Gettelman ◽  
Jan Cermak ◽  
Guy Dagan ◽  
Michael Diamond ◽  
...  
Keyword(s):  
Forest Fires ◽  
Radiative Forcing ◽  
Volcanic Eruptions ◽  
Point Sources ◽  
Natural Experiments ◽  
Experimental Conditions ◽  
Anthropogenic Aerosol ◽  
Aerosol Radiative Forcing ◽  
Wide Range ◽  
Aerosol Radiative

Abstract. Aerosol-cloud interactions (ACI) are considered to be the most uncertain driver of present-day radiative forcing due to human activities. The non-linearity of cloud-state changes to aerosol perturbations make it challenging to attribute causality in observed relationships of aerosol radiative forcing. Using correlations to infer causality can also be challenging when meteorological variability also drives both aerosol and cloud changes independently. Natural and anthropogenic aerosol perturbations from well defined sources provide “opportunistic experiments” (also known as natural experiments) to investigate ACI in cases where causality may be more confidently inferred. These perturbations cover a wide range of locations and spatio-temporal scales, including point sources such as volcanic eruptions or industrial sources, plumes from biomass burning or forest fires, and tracks from individual ships or shipping corridors. We review the different experimental conditions and conduct a synthesis of the available satellite data sets and field campaigns to place these opportunistic experiments on a common footing, facilitating new insights and a clearer understanding of key uncertainties in aerosol radiative forcing. Strong liquid water path increases due to aerosol perturbations are largely ruled out by averaging across experiments. Cloud albedo perturbations are strongly sensitive to background meteorological conditions. Opportunistic experiments have significantly improved process level understanding of ACI, but it remains unclear how reliably the relationships found can be scaled to the global level, thus, demonstrating a need for deeper investigation in order to improve assessments of aerosol radiative forcing and climate change.

Impact of air pollution on reproductive health in Afghanistan

2020 ◽  
pp. 1-8
Author(s):  
Khalid Akbar ◽  
Taj Mohammad Khaksar
Keyword(s):  
Air Pollution ◽  
Forest Fires ◽  
Power Plants ◽  
Indoor Air Pollution ◽  
Volcanic Eruptions ◽  
Point Sources ◽  
Exhaust Emission ◽  
Crustal Material ◽  
Vehicle Exhaust ◽  
High Level

The presence of one or more contaminants (harmful substances) in the atmosphere in a specific quantity, for such duration, which is injurious or tends to be injurious to human health, welfare, animal, or plant life is called air pollution. Air pollutants are of commonly two types, which are produced through natural pollutants; they include dust (crustal material), sea salts, biological material, pollen, spores or plant-animal debris, volcanic eruptions (which release a very large quantity of gases and particles into the atmosphere), periodic forest fires, thunderbolts, wind erosion, and low concentration ozone. Other types of pollutants are produced in human-made (technical) environments, like mobile sources (cars, trucks, airplanes, marine engines, etc.) or point sources (factories, electric power plants, etc.). The high level of air pollution is a big problem all over the world and also in Afghanistan, and all residents of this country are severely exposed to this ever-worsening situation. Air pollution and other extraordinary environmental problems are factors that threaten the livelihood of millions of Afghans, as a study report shows that 60% of Kabul’s residents are exposed to increased levels of harmful toxins, such as, nitrous oxides and sulfur dioxide. According to the State of Global Air report, more than 26,000 afghan deaths could be attributed to pollution in 2007, but United Nations Assistance Mission in Afghanistan (UNAMA) documented nearly 3,500 civilian casualties from the war for the same time period, so air pollution is killing more Afghans than war because they burn anything possible to get energy and heat they need. Result of air sampling in major urban centers of Afghanistan shows high amounts of particulate matters (PM), benzo-a-pyrene, and polycyclic aromatic hydrocarbons (PAHs) originating from vehicle exhaust emission. The highest concentrations were founded in Kabul and Mazar-e-Sharif (13.6 ng/m3 ). The absence of industrial parks, nonconformity of environmental protection rules, especially by industries, urbanization, degradation of fertile lands, deforestation, seasonal winds, drought, internal migration, and low knowledge about pesticides and herbicides use, are factors that boost the severity of air pollution in Afghanistan. In Afghanistan, women are more exposed to high levels of indoor air pollution because they spend more time at home due to their cultural rules; also, women have responsibility for household activities, working in the kitchen to prepare food, they are exposed to poor sanitation and contaminated water supplies, they clean and sweep rooms and yards with inadequate protection equipment, which are significant sources of dust, so they are often exposed to high levels of smoke and dust for long periods.

scholarly journals Spatial and Temporal Variation of PM10 from Industrial Point Sources in a Rural Area in Limpopo, South Africa

2019 ◽  
Vol 16 (18) ◽  
pp. 3455 ◽  
Author(s):  
Cheledi E. Tshehla ◽  
Caradee Y. Wright
Keyword(s):  
South Africa ◽  
Air Pollution ◽  
Forest Fires ◽  
Complex Terrain ◽  
Road Dust ◽  
Point Sources ◽  
Spatial And Temporal Variation ◽  
Valley Wind ◽  
Simple Kriging ◽  
Pm10 Emissions

Air pollution from industrial point sources accounts for a large proportion of air pollution issues affecting many communities around the world. However, emissions from these sources are technically controllable by putting in place abatement technologies with feasible and stringent regulatory conditions in the operation licenses. Pollution from other sources such as soil erosion, forest fires, road dust, and biomass burning, are subject to several unpredictable natural or economic factors. In this study, findings from dispersion modelling and spatial analysis of pollution were presented to evaluate the potential impacts of PM10 emissions from point sources in the Greater Tubatse Municipality of Limpopo, South Africa. The Air Pollution Model (TAPM) was used to model nested horizontal grids down to 10 km for meteorology and 4 km resolution for air pollution was used for simulation of PM10. An analysis of annual and seasonal variations of PM10 emissions from point sources was undertaken to demonstrate their impact on the environment and the surrounding communities based on 2016 emissions data. A simple Kriging method was used to generate interpolation surfaces for PM10 concentrations from industrial sources with the purpose of identifying their areas of impact. The results suggest that valley wind channeling is responsible for the distribution of pollutants in a complex terrain. The results revealed that PM10 concentrations were higher closer to the sources during the day and distributed over a wide area during the night.

Use of night vision goggles for aerial forest fire detection

2014 ◽  
Vol 23 (5) ◽  
pp. 678 ◽  
Author(s):  
L. Tomkins ◽  
T. Benzeroual ◽  
A. Milner ◽  
J. E. Zacher ◽  
M. Ballagh ◽  
...  
Keyword(s):  
Forest Fires ◽  
Bright Light ◽  
Fire Detection ◽  
Point Sources ◽  
Night Vision ◽  
Line Of Sight ◽  
Night Time ◽  
Hit Rate ◽  
Potential Source ◽  
Clear Line

Night-time flight searches using night vision goggles have the potential to improve early aerial detection of forest fires, which could in turn improve suppression effectiveness and reduce costs. Two sets of flight trials explored this potential in an operational context. With a clear line of sight, fires could be seen from many kilometres away (on average 3584m for controlled point sources and 6678m for real fires). Observers needed to be nearer to identify a light as a potential source worthy of further investigation. The average discrimination distance, at which a source could be confidently determined to be a fire or other bright light source, was 1193m (95% CI: 944 to 1442m). The hit rate was 68% over the course of the controlled experiment, higher than expectations based on the use of small fire sources and novice observers. The hit rate showed improvement over time, likely because of observers becoming familiar with the task and terrain. Night vision goggles enable sensitive detection of small fires, including those that were very difficult to detect during daytime patrols. The results demonstrate that small fires can be detected and reliably discriminated at night using night vision goggles at distances comparable to those recorded for daytime aerial detection patrols.

Solid angles and the impact of receiver-array geometry on microseismic moment-tensor inversion

Geophysics ◽  
2011 ◽  
Vol 76 (6) ◽  
pp. WC77-WC85 ◽  
Author(s):  
David W. Eaton ◽  
Farshid Forouhideh
Keyword(s):  
Least Squares ◽  
Condition Number ◽  
Solid Angle ◽  
Moment Tensor ◽  
Random Noise ◽  
Point Sources ◽  
Moment Tensor Inversion ◽  
Receiver Array ◽  
Observation Wells ◽  
The Impact

Seismic moment tensors provide a concise mathematical representation of point sources that can be used to characterize microseismic focal mechanisms. After correction for propagation effects, the six independent components of a moment tensor can be found by least-squares inversion based on P- and/or S-waveform (or spectral) amplitudes observed at different directions from the source. Using synthetic waveform data, we investigated geometrical factors that affect the reliability of such inversions. We demonstrated that the solid angle subtended by the receiver array, as viewed from the source location, plays a fundamental role in the stability of the inversion. In particular, the condition number of the generalized inverse scales approximately inversely with the solid angle, implying that for a solid angle of zero (as is the case for a single vertical borehole) the inversion is ill-conditioned. The presence of random noise alsohas a significant effect on the inversion results; our results showed that the signal-to-noise ratio (S/N) for reliable inversion scales approximately as the square root of the condition number. Taken together with geometrical considerations, we found that a [Formula: see text] is generally needed to obtain reliable inversion results for the full moment tensor under certain microseismic acquisition scenarios that include dual observation wells or surface star pattern. Our numerical tests indicated that least-squares moment-tensor solutions obtained under nonideal conditions are biased toward limited regions of the full parameter space. In particular, random noise introduces a bias toward volumetric source types, whereas ill-conditioned inversions may exhibit bias toward poorly resolved eigenvector(s) of the inversion matrix. Possible strategies to improve the reliability of moment-tensor inversion include ensuring a nonzero solid-angle aperture by using multiple observation wells, and/or incorporating other types of data such as a priori knowledge of fracture orientation.

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