The Axe Has Been Reinvented

April 19, 2014 by kris de decker Filed Under: Hand tools, Random

“Chopping firewood with traditional axes is often a laborious and even dangerous task. There is always the risk of hitting your own leg with the axe. From this imperfect situation began the pursuit to develop a better axe. It took several years, thinking and testing different exotic methods of chopping wood that were available for purchase at the time, before the idea was born. The traditional axe uses a wedge-shaped head to split the wood, but could this mechanism be improved by using leverage? From this idea the new axe was born, the Leveraxe.

finse hefboombijl

The operational principle of the Leveraxe is totally different from the traditional axe. Upon hitting the top of the log and penetrating it slightly, the leading edge of the axe head begins to slow down. Where the axe blade widens sharply it stops the axe’s penetration. However, the mass of the axe head still has kinetic energy and the off line center of gravity forces it to rotate eccentrically down towards the wood. This rotational movement causes the leading edge, or sharp edge of the blade to turn in a lever action, forcing a split with all the force of the kinetic energy of the axe multiplied by the leverage of the axehead. The widening blade edge also has a benefit in that it helps to prevent the axe from penetrating into the wood and getting stuck there as is often the case with traditional axes.

The 1.9kg axe head has a significant amount of kinetic energy when it begins the rotational movement. While the centre of gravity of the head continues first to the right and then downwards the edge moves in a rotational direction to the left. This movement uses the rotational torque to split a log and push it away from the wood. In total the edge opens the wood by 8 cm. When the axe has rotated sideways it has used most of its energy and ends on top of the log on the in a sideways fashion. This safety feature ensures that the axe does not continue towards your legs and the axe remains totally in control. In addition, the axe holds the log steady on the chopping block ready for the next swing.”

The Finnish Leveraxe. Via Boing Boing and Hackernews. Thanks to Thomas Varney and Brice Waegenire.

How Biomass Energy Has Become the New Coal

April 17, 2014 by kris de decker Filed Under: Ecotech Myths, Energy, Random

“The biomass power industry is undergoing a new surge of growth in the United States. While bioenergy has traditionally been used by certain sectors such as the paper-making industry, more than 70 new wood-burning plants have been built or are underway since 2005, and another 75 proposed and in various stages of development, fueled by renewable energy subsidies and federal tax credits. In most states, biomass power is subsidized along with solar and wind as green, renewable energy, and biomass plant developers routinely tell host communities that biomass power is “clean energy.”

teesside biomass power plant

Promotional photo of BEI-Teesside, a planned biomass power plant in the UK. The volcanoe shape is well chosen if you consider the pollution that is produced by biomass power plants.

But this first-ever detailed analysis of the bioenergy industry reveals that the rebooted industry is still a major polluter. Comparison of permits from modern coal, biomass, and gas plants shows that a even the “cleanest” biomass plants can emit > 150% the nitrogen oxides, > 600 % the volatile organic compounds, > 190% the particulate matter, and > 125% the carbon monoxide of a coal plant per megawatt-hour, although coal produces more sulfur dioxide (SO2). Emissions from a biomass plant exceed those from a natural gas plant by more than 800% for every major pollutant.

Biomass power plants are also a danger to the climate, emitting nearly 50 percent more CO2 per megawatt generated than the next biggest carbon polluter, coal. Emissions of CO2 from biomass burning can theoretically be offset over time, but such offsets typically take decades to fully compensate for the CO2 rapidly injected into the atmosphere during plant operation.”

Read the report: Trees, Trash, and Toxics: How Biomass Energy Has Become the New Coal (PDF), Mary S. Booth, Partnership for Policy Integrity, April 2, 2014. Via biofuelwatch.

Walking Made Us Fly

April 15, 2014 by kris de decker Filed Under: Low-tech living, Travel, Walking

“The first time I went on a really long walk, an absurd six-day walk following the exact border of a municipality in the east of the Netherlands, walking through fields, crossing canals, entering peoples’ houses, sleeping on the border in a small tent, I felt the way I had felt as a kid when I went out exploring the vast forest behind my parents’ house.

Some people would rather have wings but we don’t, we have feet. We were born to walk. Scientists say that walking gave us our brain capacity, walking turned us into the human beings we are. Walking made it possible for us to have the desire to fly and to come up with ways to turn our dreams into reality.

Walking made us fly. We can go anywhere. Still the easier it becomes to move through this world, the more disconnected we seem to get from it. We have to land again. Get close to the things. Be part of the world. Walking teaches us where we are, who we are. A slow speed makes our brain work fast. Makes us see more. Be more. And best of all: walking makes time disappear.”

Read more: A Soft Armour by Monique Besten. Previously: Our Right to be Oustide.

A Tourist Monoculture

April 15, 2014 by kris de decker Filed Under: Planes, Random, Travel

barcelona tourism 5

“This is not a city to live in. It’s a theme park where there’s no local life left. It’s all decoration.”

“Tourism is not going to be forever, and it’s destroying other ways of life.”

“We cannot live with those floods of people day after day.”

These are some quotes from Bye Bye Barcelona (59m, with English subtitles), a shocking documentary about tourism’s destructive effect on the culture of a city. Barcelona in Spain is the fourth most visited city in Europe after London, Paris and Rome, yet it is much smaller than those cities. The 1.5 million Barcelonians received more than 8 million tourists in 2013, most of them flown in by low-cost airlines. This compares to “only” 3.1 million tourists in 2000.

Bye Bye Barcelona, Eduardo Chibas, March 2014. Thanks to Adriana Parra.

Clothing Insulation with Different Drapes of Sari Ensembles

April 14, 2014 by kris de decker Filed Under: Clothes, Random

The word “sari” means a strip of cloth. Historic literature points towards the use of this garment even during the Indus Valley civilization in circa 3000 BC. India has a very long and rich textile tradition. The saris vary in style, material and embellishment across the regions and cultures. A recent large-scale yearlong field study in 28 Indian offices has shown that 99% of Indian women are dressed in Indian ensembles. However, knowledge on the sari’s clothing insulation is very limited in the current codes. ASHRAE standards carry the clo values of many western-style ensembles only.

The sari in its modern day avatar is a single rectangular piece of unstitched cloth: 1.15 – 1.25 m wide and 5 to 8.1 m long. The draping style of sari varies with geographical area and the activity of the female, while there are more than a hundred known styles of draping. A unique feature of sari is that it changes the insulation level significantly just by adjusting the drapes, and there are many ways to drape the upper body and lower body. The drape of the ensemble depends on several factors including weather, occassion, and activity of the person and it alters the microclimate around various body parts.

sari clothing insulation

The steps of sari draping in “nivi” style. Source: Saris: An Illustrated Guide to the Indian Art of Draping (PDF), C. Boulanger, 1997.

For this study we used the most popular “nivi” style of draping along with its four subvariations using two 5.75 m long saris. We draped a female manikin in two different saris. These are (1) a heavy weight poly-cotton handloom sari, and (2) a lightweight pure silk sari made in the Indian states of Karnataka and Tamilnadu respectively. All together, we tested nine combinations of ensemble/drapes commonly observed in office buildings in both winter and summer.

Unlike the western outfits, the sari was found to be a unique ensemble offering a range of clothing insulation, rather than a single value for a given set of garments of the ensemble depending on the drape. We noted the clothing insulation varying by about 35% due to the changes in drape on the upper body alone. The winter ensembles had a clothing insulation of 1.11 to 1.39 clo, while the summer and monsoon ensembles provided 0.62 to 0.96 clo as clothing insulation.

Quoted from: Versatile Indian sari: Clothing insulation with different drapes of typical sari ensembles, Madhavi Indraganti et al, Proceedings of 8th Windsor Conference: Counting the Cost of Comfort in a Changing World, Cumberland Lodge, Windsor, UK, 10-13 April 2014. London: Network for Comfort and Energy Use in Buildings. Many thanks to Elizabeth Shove.

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The Dobsonian Telescope

April 10, 2014 by kris de decker Filed Under: DIY, Telescopes

the dobsonian telescope“The design of this telescope is called a Dobsonian, after its inventor John Dobson, who passed away earlier this year. Dobson’s life took an unusual trajectory. He went from being a self described “belligerent atheist” to a monk in the Vendanta society to co-founding the San Francisco Sidewalk Astronomers.  Most of his life was spent bringing the night sky to people around the world and teaching people how to make their own low-cost telescopes.

As a monk, Dobson could not afford expensive materials. He kept the design inexpensive by using a simple mount and cheap materials: wood and cardboard. My Dobsonian was made by the now defunct Coulter Optical Company out of particle board and a cardboard concrete form. Its large 13.1 inch mirror makes it perfect for looking at nebulas, galaxies and star clusters even in light polluted urban areas.”

Find out more. Illustration.