J. Ozuomb, C. Edebeatu, F. Opara, M. Udoye, N. Okonkwo. A possibility to combat the intake of poor quality drinking water by Nigerians using a locally fabricated solar water distillation kit. Advances in Applied Science Research, Aug2012, Vol. 3 Issue 4, p2204-2211.
Nigeria is blessed with abundant solar energy and potable water shortage is one of her major challenges. A rooftype solar water distillation (RSWD) system was fabricated from local materials and tested under actual environmental conditions of Urualla, an ancient town in the Eastern part of Nigeria. The system includes four major components; a rectangular wooden basin, an absorber surface, a glass roof and a condensate channel. The RSWD system is very cheap and has no moving parts. Hence, the cost of maintenance is almost free coupled with free source of energy. The RSWD of surface area 0.5m2 was able to produce an average of 0.4m3 of distilled water per day. Though the condensate was small compared to human need as is peculiar to many solar stills, the efficiency can be increased by fabricating RSWDs of larger surface area. Also, since the materials are cheap and readily available, one can fabricate as many RSWDs as possible to tackle the daily demand of potable water.
Title: “Aerial System” vice original Title of “Aerostat System”
Sol. #: SOL-CI-12-00049
Agency: Environmental Protection Agency
Office: Office of Acquisition Management
Posted On: Nov 13, 2012 10:36 am
Current Type: Combined Synopsis/Solicitation (Modified)
Base Type: Combined Synopsis/Solicitation
Base Posting Date: Oct 29, 2012 2:52 pm
The U.S. EPA is looking to purchase a maneuverable, aerial system capable of lofting an approximately 23 kg (50 lb) payload to heights of up to about 300 m (1,000 ft). The aerial system will be used to sample emissions above a variety of open area sources, including prescribed fires, detonations, and industrial area sources. The aerial system must be maneuverable at a user-controlled altitude and coordinates either via electric (preferred) or non-carbon fuel self-propulsion or via a ground-based tether on a mobile platform or a combination thereof. It must have the following capabilities.
MINIMUM OPERATIONAL REQUIREMENTS
• At least 2 hour loft time
• Capable of lofting, minimally, a 14 kg payload. Desired payload is 23 kg.
• If lighter-than-air, a gas manifold and hose
• Capable of being launched and retrieved with five or less persons.
• Capable of being transported in a 20′ trailer or less; trailer not necessary for this contract.
• Ability to takeoff within a 500 m x 50 m area
• Operable and maneuverable in winds up to 15 mph, gusts to 25 mph
• Operable in light rain, humid conditions, 0 to 40 oC.
• Can be initially deployed within 150 min
• Automated safe return or rapid landing feature if ground control or wireless connection fails.
• Capable of maintaining a fixed position (+/- 10m) wrt to the ground and altitude.
• Altitude capabilities from 20 m to 300 m.
• Maneuverable at altitude from ground-based, remote (at least 2000 m) control
• Can maneuver or be maneuvered to move at 4m/sec (10 mph) in a quiescent atmosphere.
• Capable of being oriented in relation to the ground and maintaining that orientation.
• If tethered,
o capable of moving into the wind to a position lateral and perpendicular to its secure point
o If tethered, single tether only, 1,000 lb test
o Battery operated (use of 12 V) electric winch with remote control (2000 m range)
o Winch can fit in the back bed of an ATV such as a John Deere Gator
o Winch components less than 150 lbs each
o A level wind, or a mechanism to spread the tether across the width of the tether spool
o Design and materials to minimize tether wear
o Variable speed, reversible winch, capable of 0 to 50 m/min
o Tether and winch capable of 1,000 lb tensile strength
o Brake that can be applied during high speed operation and is locking
o Remote control winch at 1000 m
• Can be retrieved from 150 m altitude within 2 min and re-lofted to 150 m altitude within 2 min of launch
• Flight-tolerant of turbulence such as that expected from open fire thermals such as forest fires
• Must meet a payload capacity which includes a 3.05 kg, 48 V DC battery with a 10 Amp hour capacity. The Contractor can supply these power requirements and reduce the required loft capacity by 3.05 kg. The power supply should handle a 40 Amp surge.
Posted in EPA
H. Buhaug. Climate not to blame for African civil wars. Proceedings National Academy of Sciences. Sept. 7, 2010. doi: 10.1073/pnas.1005739107
Abstract: Vocal actors within policy and practice contend that environmental variability and shocks, such as drought and prolonged heat waves, drive civil wars in Africa. Recently, a widely publicized scientific article appears to substantiate this claim. This paper investigates the empirical foundation for the claimed relationship in detail. Using a host of different model specifications and alternative measures of drought, heat, and civil war, the paper concludes that climate variability is a poor predictor of armed conflict. Instead, African civil wars can be explained by generic structural and contextual conditions: prevalent ethno-political exclusion, poor national economy, and the collapse of the Cold War system.
Click here for full paper (free).
Posted in Climate
Q. Tang and G. Leng 2012. Damped summer warming accompanied with cloud cover increase over Eurasia from 1982 to 2009. Environ. Res. Lett. 7 014004 doi:10.1088/1748-9326/7/1/014004
The relationship between summer temperature, total cloud cover and precipitation over Eurasia was investigated using observation-based products of temperature and precipitation, and satellite-derived cloud cover and radiation products. We used a partial least squares regression approach to separate the local influences of cloud cover and precipitation on temperature variations. Our results suggest that the variance of summer temperature is partly explained by changes in summer cloudiness. The summer temperature dependence on cloud cover is strong at the high latitudes and in the middle latitude semi-humid area, while the dependence on precipitation is strong in the Central Asia arid area and the southern Asia humid area. During the period 1982–2009, the damped warming in extended West Siberia was accompanied with increases in cloud cover, and the pronounced warming in Europe and Mongolia was associated with a decrease in cloud cover and precipitation. Our results suggest that cloud cover may be the important local factor influencing the summer temperature variation in Eurasia while precipitation plays an important role at the middle latitudes.
Posted in Climate
P.Sorrel, M. Debret, I. Billeaud, S.L. Jaccard, J.F. McManus, and B. Tessier. Persistent non-solar forcing of Holocene storm dynamics in coastal sedimentary archives. Nature Geoscience. (2012) doi:10.1038/ngeo1619
Considerable climatic variability on decadal to millennial timescales has been documented for the past 11,500 years of interglacial climate. This variability has been particularly pronounced at a frequency of about 1,500 years, with repeated cold intervals in the North Atlantic. However, there is growing evidence that these oscillations originate from a cluster of different spectral signatures, ranging from a 2,500-year cycle throughout the period to a 1,000-year cycle during the earliest millennia. Here we present a reappraisal of high-energy estuarine and coastal sedimentary records from the southern coast of the English Channel, and report evidence for five distinct periods during the Holocene when storminess was enhanced during the past 6,500 years. We find that high storm activity occurred periodically with a frequency of about 1,500 years, closely related to cold and windy periods diagnosed earlier. We show that millennial-scale storm extremes in northern Europe are phase-locked with the period of internal ocean variability in the North Atlantic of about 1,500 years. However, no consistent correlation emerges between spectral maxima in records of storminess and solar irradiation. We conclude that solar activity changes are unlikely to be a primary forcing mechanism of millennial-scale variability in storminess.
Posted in Climate