Archive for June 2013
Snow sensing helps to predict water shortages
"OUR water supply is always under threat." Like most farmers in California's fertile San Joaquin valley, Zachary Sheely is dependent on snowmelt from the Sierra Nevada mountains for his livelihood. But the snows have become sparse and inconsistent, complicating decisions on which crops to grow. "We are getting more and more years in a row with extreme conditions so the risk to our crops is huge," he says.
Help could soon be at hand. A pair of airborne sensors developed by NASA, coupled with on-the-ground smartphone apps, could make the lives of farmers like Sheely a little easier.
Estimates of the volume of snow on a mountain and the meltwater it will produce are usually made manually, so are error-prone. "They go out there with sticks to measure snow depth," Sheely says. This makes planning which crops to grow a nightmare. If Sheely knew water was going to be scarce, he could cut back on thirsty crops like almonds and grapes. "These are huge decisions with huge risks attached for farmers," he says.
Estimates of the volume of snow on a mountain and the meltwater it will produce are usually made manually, so are error-prone. "They go out there with sticks to measure snow depth," Sheely says. This makes planning which crops to grow a nightmare. If Sheely knew water was going to be scarce, he could cut back on thirsty crops like almonds and grapes. "These are huge decisions with huge risks attached for farmers," he says.
To change that, Tom Painter and a team of engineers at NASA's Jet Propulsion Lab (JPL) have equipped a light aircraft with two sensors that can precisely measure the volume of snow present while flying over mountain ranges. A laser-based radar measures the depth and density of the snow, so the amount of water present can be determined, while a spectrometer measures how much sunlight the snow is reflecting and absorbing. This can predict how fast it will melt and run down into the valleys in the summer.
In April, the plane, called the Airborne Snow Observatory, began a three-year series of test flights over two mountain water sources in the US: the Tuolumne river basin in the Sierras and the Uncompahgre river in the Upper Colorado river basin.
Early results look good. The flights allow for accurate mapping of the snow cover and reveal how much meltwater it is expected to generate. Within 24 hours, this information can be supplied to farms and water-using businesses like power stations. The flights – currently operating once a week – are making one thing clear: "Snowpack is going fast this year. It's very, very dry," Painter told New Scientist.
In California, snowpack was only around 17 per cent of its average May volume, according to the California Department of Water Resources in Sacramento. As a result, farmers may only get a fraction of the water they need this summer, says Sheely, who has already decided to leave a tenth of his land fallow.
The situation is equally tense further east, in the basins fed by snow in the Rocky Mountains. "The Colorado river basin has been experiencing drought conditions dating back to 1999," says Anne Castle, assistant secretary for water and science at the US Department of the Interior. "All areas in the basin are struggling with the prospect of permanently reduced supplies, so water managers would welcome earlier, better and more detailed forecasts.
Richard Atwater, executive director of the Southern California Water Committee, says JPL's snowpack maps will result in "better decisions on storing or releasing water behind each dam and reservoir", helping save water for long, hot summers.
Meanwhile, Sheely is being proactive. Working with Colorado-based agri-tech company AgWorld, he has developed an iPad app that helps farmers make the most of drier conditions. He hopes the app will establish a collaborative network in which farmers input and share data on local conditions in a bid to make their irrigation operations more efficient and sustainable. He plans to enable later versions to incorporate the snowmelt predictions made by the Airborne Snow Observatory, plus soil moisture readings from sensors placed in fields – giving the growers an unprecedented picture of their crops' prospects.
Gayle Holman of farming advocacy group Westlands Water District thinks farmers like Sheely are the future. "His apps for advanced irrigation practices enable growers to utilise state-of-the-art water conservation practices," she says. "Growers like Sheely have become part of the solution for water supply reliability."
Ultra Elevator with Carbon- Fiber Tape Takes You Higher
Going up? Elevators can now carry people to the top of a kilometre-high skyscraper in a single run. The key is the development of a super-light and super-strong lift-hoisting cable. The sheer weight of the steel cable that hoists today's elevators has prevented them going any higher than 500 metres in one go.
That means, for instance, that people in Dubai's 828-metre-high Burj Khalifa tower, currently the world's tallest building, have to switch lifts to go above the 500-metre mark. But lifts in the nascent Kingdom Tower in Jeddah, Saudi Arabia – due to top out above 1 kilometre in 2019 – could use the new technology to zoom to the top in one go.
With at least 20 buildings more than 500 metres high on architects' drawing boards around the world, and more expected as megacities proliferate, lift maker Kone Corporation of Espoo, Finland, has been engineering ways to move people up and down them in more convenient and less energy-intensive ways. In London yesterday it revealed its solution: UltraRope.
With at least 20 buildings more than 500 metres high on architects' drawing boards around the world, and more expected as megacities proliferate, lift maker Kone Corporation of Espoo, Finland, has been engineering ways to move people up and down them in more convenient and less energy-intensive ways. In London yesterday it revealed its solution: UltraRope.
Instead of interwound steel hawsers, Kone's hoisting line comprises four carbon-fibre tapes sealed in transparent plastic about 4 centimetres wide and 4 millimetres thick. It's more like a belt than a rope and looks like a school ruler shot through with magnetic tapes.
UltraRope beats steel for tensile strength but weighs only one-seventh as much. "That's a tremendous amount of steel you won't have to move around the building," says Kone's head of technology, Johannes de Jong. "And it will last longer than steel too."
The material has been under test in a 333-metre-deep mineshaft in Lohja, Finland, since 2004. That may seem a long time, but because lives will depend on UltraRope, de Jong and his colleagues had to ensure it ages safely. As well as repeatedly heating and cooling it to tropical and arctic temperatures to accelerate the ageing process, they also tested its fire resistance and even the effect that tools dropped down a lift shaft could have on it. It has now passed all European Union and US certification tests, de Jong says.
UltraRope will also save energy. Simulating its use in a 640-metre-high building, Kone found that the elevator used 11 per cent less electrical power than a steel-cabled version.
Kone's main rival, Otis Elevator of Farmington, Connecticut, is also looking at carbon fibre for use in future ultra-tall buildings. However, the US company is thinking of using the material to strengthen steel cables.
"UltraRope is one of the biggest breakthroughs since the advent of the [Otis] safety elevator 150 years ago," says Antony Wood, executive director of the Council on Tall Buildings and Urban Habitat in Chicago.
"The biggest limiting factor in building higher until now has been the steel rope weight – and we have reached the limit of that technology at 500 metres."
With 200,000 people moving to, or being born into, urbanised environments every day, according to the UN, Wood sees building ever upwards in megacities as a valid – though difficult – answer to housing people. "Where will all those people go? Horizontally expanding suburbs? If they do that, we're all screwed."
Automatic Counting & Packing of incense sticks using PLC
At
present we have many machines on making incense sticks. Machines are even
faster in making the sticks, but the count & packing is done manually,
which may have certain effects on the industry. So to overcome the effects the
system should be automated. As Incense sticks are counted manually, the sticks
may get damage in some cases. The automation process is required here so that
the process is maintained in a proper order.
PROGRAMMABLE LOGIC CONTROL (PLC)
The first PLC was developed by group of engineers at general motors 1968, when searching for an alternative to replace the relay control systems.
- Simple programming
- program changing without system intervention
- smaller, cheaper & more reliable
- simple & low cost maintenance
For instance, even if program optimization and thus a reduction of required memory capacity initially still represented an important key task for the programmer, nowadays this is hardly of any significance.
Subsequent development resulted in a system which enabled the simple connection of binary signals. The requirements as to how these signals were to be connected was specified in the control program.
Since then, three decades have passed, during which the enormous progress made in the development of micro electronics did not stop short of programmable logic controllers.
Basic design of a PLC:
The function of an input module is to convert incoming signals into signals which can be processed by the PLC and to pass these to the central control unit. The Reverse task is performed by an output module. This Converts the PLC Signal into signals suitable for the
actuators.
Depending on how the central control unit is connected to the input and output modules, differentiation can be made between compact PLCs . A wide range of variants exists, particularly in the case of more recent PLCs. These include both modular as well as compact characteristics and important features such as
spacing saving, flexibility and scope for expansion.
The hardware design for a programmable logic controller is such that it is able to withstand typical industrial environments as regard signal levels, heat, humidity, fluctuations in current supply and mechanical impact.
ELECTRO-PNEUMATICS
ELECTRO-PNEUMATICS
Electro-pneumatics is successfully used in many areas of industrial automation. Production, assembly and packaging systems worldwide are driven by electro-pneumatic control systems.
The change in
requirements together with technical advances has had a considerable impact on
the appearance of controls. In the signal control section, the relay has
increasingly been replaced by the programmable logic controller in order to
meet the growing demand for more flexibility. Modern electro-pneumatic controls
also implement new concepts in the power section to meet the needs of modern
industrial practice. Examples of this are the valve terminal, bus networking
and proportional pneumatics.
Tag :
Technology
PNEUMATICS (PNEUMATIC SYSTEM)
PNEUMATIC SYSTEM
Fluid is that deforms continuously
on the application of shear stress, no matter how much small is it. Fluid
comprises both gases and liquid. The technique of using liquid for power
transmission is called as hydraulics, while which uses gases for power
transmission is called Pneumatics. In most hydraulics system mineral oils will
be used, while in most pneumatic system atmospheric air will be used.
Tag :
Technology
