Spotlights

A world of sonic wonder
October 27, 2011 08:03 AM - BBC Earth Team

The First wonder, Speaking Sands For nearly a century, man has been baffled by the sound of singing sand dunes. The songs they emit are almost as diverse as the countless theories about how they occur. The sound is produced when the sand on the surface of dunes avalanches. It was once thought that these sounds were produced by the friction between the grains. More recent studies have revealed that the sound continues after the sand has stopped moving and the song that the dunes sing varies depending on the time of year. Some researchers now theorise that the sound is caused by the reverberation between dry sand at the surface and a band of wet sand within the dune, hence it changes seasonally. There are approximately thirty locations around the world where these booming dunes can be heard; the earliest records seem to date to Marco Polo’s time in the Gobi Desert. However you don’t need to adventure among the dunes to hear them sing; the strange sound, said to be like the drone of a low flying propeller plane, has reportedly been heard up to ten kilometres away from its source.

A world of sonic wonder
October 27, 2011 08:03 AM - BBC Earth Team

The First wonder, Speaking Sands For nearly a century, man has been baffled by the sound of singing sand dunes. The songs they emit are almost as diverse as the countless theories about how they occur. The sound is produced when the sand on the surface of dunes avalanches. It was once thought that these sounds were produced by the friction between the grains. More recent studies have revealed that the sound continues after the sand has stopped moving and the song that the dunes sing varies depending on the time of year. Some researchers now theorise that the sound is caused by the reverberation between dry sand at the surface and a band of wet sand within the dune, hence it changes seasonally. There are approximately thirty locations around the world where these booming dunes can be heard; the earliest records seem to date to Marco Polo’s time in the Gobi Desert. However you don’t need to adventure among the dunes to hear them sing; the strange sound, said to be like the drone of a low flying propeller plane, has reportedly been heard up to ten kilometres away from its source.

A world of sonic wonder
October 27, 2011 08:03 AM - BBC Earth Team

The First wonder, Speaking Sands For nearly a century, man has been baffled by the sound of singing sand dunes. The songs they emit are almost as diverse as the countless theories about how they occur. The sound is produced when the sand on the surface of dunes avalanches. It was once thought that these sounds were produced by the friction between the grains. More recent studies have revealed that the sound continues after the sand has stopped moving and the song that the dunes sing varies depending on the time of year. Some researchers now theorise that the sound is caused by the reverberation between dry sand at the surface and a band of wet sand within the dune, hence it changes seasonally. There are approximately thirty locations around the world where these booming dunes can be heard; the earliest records seem to date to Marco Polo’s time in the Gobi Desert. However you don’t need to adventure among the dunes to hear them sing; the strange sound, said to be like the drone of a low flying propeller plane, has reportedly been heard up to ten kilometres away from its source.

A world of sonic wonder
October 27, 2011 08:03 AM - BBC Earth Team

The First wonder, Speaking Sands For nearly a century, man has been baffled by the sound of singing sand dunes. The songs they emit are almost as diverse as the countless theories about how they occur. The sound is produced when the sand on the surface of dunes avalanches. It was once thought that these sounds were produced by the friction between the grains. More recent studies have revealed that the sound continues after the sand has stopped moving and the song that the dunes sing varies depending on the time of year. Some researchers now theorise that the sound is caused by the reverberation between dry sand at the surface and a band of wet sand within the dune, hence it changes seasonally. There are approximately thirty locations around the world where these booming dunes can be heard; the earliest records seem to date to Marco Polo’s time in the Gobi Desert. However you don’t need to adventure among the dunes to hear them sing; the strange sound, said to be like the drone of a low flying propeller plane, has reportedly been heard up to ten kilometres away from its source.

A world of sonic wonder
October 27, 2011 08:03 AM - BBC Earth Team

The First wonder, Speaking Sands For nearly a century, man has been baffled by the sound of singing sand dunes. The songs they emit are almost as diverse as the countless theories about how they occur. The sound is produced when the sand on the surface of dunes avalanches. It was once thought that these sounds were produced by the friction between the grains. More recent studies have revealed that the sound continues after the sand has stopped moving and the song that the dunes sing varies depending on the time of year. Some researchers now theorise that the sound is caused by the reverberation between dry sand at the surface and a band of wet sand within the dune, hence it changes seasonally. There are approximately thirty locations around the world where these booming dunes can be heard; the earliest records seem to date to Marco Polo’s time in the Gobi Desert. However you don’t need to adventure among the dunes to hear them sing; the strange sound, said to be like the drone of a low flying propeller plane, has reportedly been heard up to ten kilometres away from its source.

A world of sonic wonder
October 27, 2011 08:03 AM - BBC Earth Team

The First wonder, Speaking Sands For nearly a century, man has been baffled by the sound of singing sand dunes. The songs they emit are almost as diverse as the countless theories about how they occur. The sound is produced when the sand on the surface of dunes avalanches. It was once thought that these sounds were produced by the friction between the grains. More recent studies have revealed that the sound continues after the sand has stopped moving and the song that the dunes sing varies depending on the time of year. Some researchers now theorise that the sound is caused by the reverberation between dry sand at the surface and a band of wet sand within the dune, hence it changes seasonally. There are approximately thirty locations around the world where these booming dunes can be heard; the earliest records seem to date to Marco Polo’s time in the Gobi Desert. However you don’t need to adventure among the dunes to hear them sing; the strange sound, said to be like the drone of a low flying propeller plane, has reportedly been heard up to ten kilometres away from its source.

A world of sonic wonder
October 27, 2011 08:03 AM - BBC Earth Team

The First wonder, Speaking Sands For nearly a century, man has been baffled by the sound of singing sand dunes. The songs they emit are almost as diverse as the countless theories about how they occur. The sound is produced when the sand on the surface of dunes avalanches. It was once thought that these sounds were produced by the friction between the grains. More recent studies have revealed that the sound continues after the sand has stopped moving and the song that the dunes sing varies depending on the time of year. Some researchers now theorise that the sound is caused by the reverberation between dry sand at the surface and a band of wet sand within the dune, hence it changes seasonally. There are approximately thirty locations around the world where these booming dunes can be heard; the earliest records seem to date to Marco Polo’s time in the Gobi Desert. However you don’t need to adventure among the dunes to hear them sing; the strange sound, said to be like the drone of a low flying propeller plane, has reportedly been heard up to ten kilometres away from its source.

Commentary: U.S. House of Representatives Passes Bill To Weaken EPA Clean Air Rules
October 19, 2011 01:55 PM - Dominick DalSanto, Baghouse.com

Two bills are currently working they way through the U.S. Congress in an attempt to stay activation of new air pollution regulations propagated by the U.S. Environmental Protection Agency, namely additions to the NESHAP, Cement MACT, and Boiler MACT standards scheduled to take effect in the next few months. The new regulations will require most facilities to install updated dust collection systems to meet more stringent emissions levels. The pair of bills, the Cement Sector Regulatory Relief Act of 2011 and the EPA Regulatory Relief Act of 2011, are part of a larger effort by conservatives to curtail the so-called "aggressive" agenda of the EPA. Several different EPA rule sets are covered by the bill, but the main three are the National Emission Standards for Hazardous Air Pollutants (NESHAPs), Boiler MACTs (Maximum Available Control Technology), and Cement MACTs which covers emissions from the manufacture of cement. The standards are either new, or updates to existing EPA regulations. The EPA NESHAPs cover the six basic air pollutants the EPA regulates, carbon monoxide (CO), sulfur dioxide (SO2), nitrogen oxides (NOx), particulate matter e.g. dusts smaller than 2.5 microns (PM2.5), lead, and ozone. These rules were recently revised to include stricter limits.

Commentary: U.S. House of Representatives Passes Bill To Weaken EPA Clean Air Rules
October 19, 2011 01:55 PM - Dominick DalSanto, Baghouse.com

Two bills are currently working they way through the U.S. Congress in an attempt to stay activation of new air pollution regulations propagated by the U.S. Environmental Protection Agency, namely additions to the NESHAP, Cement MACT, and Boiler MACT standards scheduled to take effect in the next few months. The new regulations will require most facilities to install updated dust collection systems to meet more stringent emissions levels. The pair of bills, the Cement Sector Regulatory Relief Act of 2011 and the EPA Regulatory Relief Act of 2011, are part of a larger effort by conservatives to curtail the so-called "aggressive" agenda of the EPA. Several different EPA rule sets are covered by the bill, but the main three are the National Emission Standards for Hazardous Air Pollutants (NESHAPs), Boiler MACTs (Maximum Available Control Technology), and Cement MACTs which covers emissions from the manufacture of cement. The standards are either new, or updates to existing EPA regulations. The EPA NESHAPs cover the six basic air pollutants the EPA regulates, carbon monoxide (CO), sulfur dioxide (SO2), nitrogen oxides (NOx), particulate matter e.g. dusts smaller than 2.5 microns (PM2.5), lead, and ozone. These rules were recently revised to include stricter limits.

Commentary: U.S. House of Representatives Passes Bill To Weaken EPA Clean Air Rules
October 19, 2011 01:55 PM - Dominick DalSanto, Baghouse.com

Two bills are currently working they way through the U.S. Congress in an attempt to stay activation of new air pollution regulations propagated by the U.S. Environmental Protection Agency, namely additions to the NESHAP, Cement MACT, and Boiler MACT standards scheduled to take effect in the next few months. The new regulations will require most facilities to install updated dust collection systems to meet more stringent emissions levels. The pair of bills, the Cement Sector Regulatory Relief Act of 2011 and the EPA Regulatory Relief Act of 2011, are part of a larger effort by conservatives to curtail the so-called "aggressive" agenda of the EPA. Several different EPA rule sets are covered by the bill, but the main three are the National Emission Standards for Hazardous Air Pollutants (NESHAPs), Boiler MACTs (Maximum Available Control Technology), and Cement MACTs which covers emissions from the manufacture of cement. The standards are either new, or updates to existing EPA regulations. The EPA NESHAPs cover the six basic air pollutants the EPA regulates, carbon monoxide (CO), sulfur dioxide (SO2), nitrogen oxides (NOx), particulate matter e.g. dusts smaller than 2.5 microns (PM2.5), lead, and ozone. These rules were recently revised to include stricter limits.

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