Look at these intelligent line drawing illusions. We are unable to find the original artist Tango, but the artist deserves a huge applause for the creative thinking.
Magnets always fascinate us and a favourite topic for many physics lovers. Magnets just not have the property to attract metals but also attracted the interests of modern day scientists. The principle of magnetism is been applied many utilities in our daily life.
Ever since the issue of global warming and fossil fuels popped up, the world is looking for an alternate energy. Transportation is one of the major factors when it comes to greenhouse gases.
How about using magnets for transportation? A transport without any fuel? without any emission? Is that possible?
Maglev Transportation is the first step towards a great future. Let us learn more about it.
What is Maglev?
Maglev (derived from magnetic levitation) is a transport method that uses magnetic levitation to move vehicles without touching the ground. With maglev, a vehicle travels along a guideway using magnets to create both lift and propulsion, thereby reducing friction and allowing higher speeds.
When you were a kid, you might have tried to balance one magnet in the air using other magnets. The same basic principle is applied using electromagnetic (maglev) tracks.
The big difference between a maglev train and a conventional train is that maglev trains do not have an engine — at least not the kind of engine used to pull typical train cars along steel tracks. The engine for maglev trains is rather inconspicuous. Instead of using fossil fuels, the magnetic field created by the electrified coils in the guideway walls and the track combine to propel the train.
Comparison with conventional trains
Maglev transport is non-contact and electric powered. It relies less or not at all on the wheels, bearings and axles common to wheeled rail systems.
- Speed: Maglev allows higher top speeds than conventional rail, but experimental wheel-based high-speed trains have demonstrated similar speeds.
- Maintenance: Maglev trains currently in operation have demonstrated the need for minimal guideway maintenance. Vehicle maintenance is also minimal (based on hours of operation, rather than on speed or distance traveled). Traditional rail is subject to mechanical wear and tear that increases exponentially with speed, also increasing maintenance.
- Weather: Maglev trains are little affected by snow, ice, severe cold, rain or high winds. However, they have not operated in the wide range of conditions that traditional friction-based rail systems have operated. Maglev vehicles accelerate and decelerate faster than mechanical systems regardless of the slickness of the guideway or the slope of the grade because they are non-contact systems.
- Track: Maglev trains are not compatible with conventional track, and therefore require custom infrastructure for their entire route. By contrast conventional high-speed trains such as the TGV are able to run, albeit at reduced speeds, on existing rail infrastructure, thus reducing expenditure where new infrastructure would be particularly expensive (such as the final approaches to city terminals), or on extensions where traffic does not justify new infrastructure.
- Efficiency: Conventional rail is probably more efficient at lower speeds. But due to the lack of physical contact between the track and the vehicle, maglev trains experience no rolling resistance, leaving only air resistance and electromagnetic drag, potentially improving power efficiency.Some systems however such as the Central Japan Railway Company SCMaglev use rubber tires at low speeds, reducing efficiency gains.
- Weight: The electromagnets in many EMS and EDS designs require between 1 and 2 kilowatts per ton. The use of superconductor magnets can reduce the electromagnets’ energy consumption. A 50-ton Transrapid maglev vehicle can lift an additional 20 tons, for a total of 70 tons, which consumes 70-140 kW. Most energy use for the TRI is for propulsion and overcoming air resistance at speeds over 100 mph.
- Weight loading: High speed rail requires more support and construction for its concentrated wheel loading. Maglev cars are lighter and distribute weight more evenly.
- Noise: Because the major source of noise of a maglev train comes from displaced air rather than from wheels touching rails, maglev trains produce less noise than a conventional train at equivalent speeds. However, the psychoacoustic profile of the maglev may reduce this benefit: a study concluded that maglev noise should be rated like road traffic, while conventional trains experience a 5–10 dB “bonus”, as they are found less annoying at the same loudness level.
- Braking: Braking and overhead wire wear have caused problems for the Fastech 360 rail Shinkansen. Maglev would eliminate these issues.
- Magnet reliability: At higher temperatures magnets may fail. New alloys and manufacturing techniques have addressed this issue.
- Control systems: No signalling systems are needed for high-speed rail, because such systems are computer controlled. Human operators cannot react fast enough to manage high-speed trains. High speed systems require dedicated rights of way and are usually elevated. Two maglev system microwave towers are in constant contact with trains. There is no need for train whistles or horns, either.
- Terrain: Maglevs are able to ascend higher grades, offering more routing flexibility and reduced tunneling.
Comparison with aircraft
Differences between airplane and maglev travel:
- Efficiency: For maglev systems the lift-to-drag ratio can exceed that of aircraft (for example Inductrack can approach 200:1 at high speed, far higher than any aircraft). This can make maglev more efficient per kilometer. However, at high cruising speeds, aerodynamic drag is much larger than lift-induced drag. Jets take advantage of low air density at high altitudes to significantly reduce air drag. Hence despite their lift-to-drag ratio disadvantage, they can travel more efficiently at high speeds than maglev trains that operate at sea level.
- Routing: While aircraft can theoretically take any route between points, commercial air routes are rigidly defined. Maglevs offer competitive journey times over distances of 800 kilometres (500 miles) or less. Additionally, maglevs can easily serve intermediate destinations.
- Availability: Maglevs are little affected by weather.
- Safety: Maglevs offer a significant safety margin since maglevs do not crash into other maglevs or leave their guideways.
- Travel time: Maglevs do not face the extended security protocols faced by air travelers nor is time consumed for taxiing, or for queuing for take-off and landing.
Despite decades of research and development, only two commercial maglev transport systems are in operation, with two others under construction. The highest recorded maglev speed is 603 km/h (375 mph), achieved in Japan by JR Central’s L0 superconducting Maglev on 2015 April,21. The Japanese trains use super-cooled, superconducting electromagnets. This kind of electromagnet can conduct electricity even after the power supply has been shut off.
Courtesy: Wikipedia, Google and Youtube
A creative mother has come up with a novel way of making sure her children eat their breakfasts – by using eggs to make works of art. Sculpted into a variety of extraordinary designs, culinary genius, Anne Widya, uses sunny side up eggs to make sure her children’s plates are always cleared. Made using a cookie cutter and sushi wrap, the mother-of-four gets her creative juices flowing by serving eggs in an assortment of shapes from smiling pigs to ice cream sundaes. Anne’s talent first began as way to cheer up her son, Andrew, who was off sick from school but soon turned into a fully fledged hobby.
Materials science, also commonly known as materials engineering, is an interdisciplinary field applying the properties of matter to various areas of science and engineering. This relatively new scientific field investigates the relationship between the structure of materials at atomic or molecular scales and their macroscopic properties. It incorporates elements of applied physics and chemistry. With significant media attention focused on Nano science and nanotechnology in recent years, materials science is becoming more widely known as a specific field of science and engineering. It is an important part of forensic engineering (Forensic engineering is the investigation of materials, products, structures or components that fail or do not operate or function as intended, causing personal injury or damage to property.) and failure analysis, the latter being the key to understanding, for example, the cause of various aviation accidents. Many of the most pressing scientific problems that are currently faced today are due to the limitations of the materials that are currently available and, as a result, breakthroughs in this field are likely to have a significant impact on the future of technology.
Courtesy : PBS Documentary via YouTube
The fresh water available in the earth is just 3%. Rain is one of the major sources of Freshwater, which we hardly consider preserving. Rainwater harvesting is a technique of collection and storage of rainwater into natural reservoirs or tanks, or the infiltration of surface water into subsurface aquifers (before it is lost as surface runoff). Even we can collect water from fog and dew! In this article we see various methods of Rain water harvesting, how to construct such harvesting facilities and many more info.
The reasons for using rainwater harvesting systems answer three questions:
- What: Rainwater harvesting will improve water supply, food production, and ultimately food security.
- Who: Water insecure households or individuals in rural areas will benefit the most from rainwater harvesting systems.
- How: Since rainwater harvesting leads to water supply which leads to food security, this will greatly contribute to income generation.
|Rainwater Harvesting TECHNOLOGIES|
|Rooftop||In situ||Surface water||Groundwater recharge||Fog and dew|
Rooftop rainwater harvesting
Rainwater harvesting refers to structures like homes or schools, which catch rainwater and store it in underground or above-ground tanks for later use. One way to collect water is rooftop rainwater harvesting, where any suitable roof surface — tiles, metal sheets, plastics, but not grass or palm leaf — can be used to intercept the flow of rainwater in combination with gutters and downpipes (made from wood, bamboo, galvanized iron, or PVC) to provide a household with high-quality drinking water. A rooftop rainwater harvesting system might be a 500 cubic meter underground storage tank, serving a whole community, or it might be just a bucket, standing underneath a roof without a gutter. Rainwater harvesting systems have been used since antiquity, and examples abound in all the great civilizations throughout history.
Rainwater harvesting requires at least an annual rainfall of 100-200 mm. Many places in Latin America have rainfalls of about 500 millimeters per year. It is suitable even when the roof is small. For example a 5 x 6 meters (that is to say 30 square meters) house, with 500 mm annual precipitation, receives a rainfall of 15.000 liters on its roof; this is a sufficient amount for a family formed by 5 members.
|– Possible in almost any climate
– Rainwater generally meets drinking water quality standards, if system is well-designed and maintained
|– Storage is needed to bridge dry periods|
In situ rainwater harvesting
In arid and semi-arid regions, where precipitation is low or infrequent during the dry season, it is necessary to store the maximum amount of rainwater during the wet season for use at a later time, especially for agricultural and domestic water supply. One of the methods frequently used in rainwater harvesting is the storage of rainwater in situ. Topographically low areas are ideal sites for in situ harvesting of rainfall. This technique has been used in the arid and semi-arid regions of northeastern Brazil, Argentina, and Paraguay, primarily for irrigation purposes. The in situ technology consists of making storage available in areas where the water is going to be utilized.
Generally this technology is simple and easy to use. Governmental organizations and the agricultural community generally work together to support and promote the in situ rainwater storage. Educational and information programs should be provided to inform users of the benefits of this technology, and the means of implementing rainwater harvesting while preventing soil loss.
This technology increases water supply for irrigation purposes in arid and semi-arid regions. It promotes improved management practices in the cultivation of corn, cotton, sorghum, and many other crops. It also provides additional water supply for livestock watering and domestic consumption. In situ is applicable to low topographic areas in arid or semi-arid climates.
Extensive use is found in northeastern Brazil, in the Chaco region of Paraguay, and in Argentina. It can be used to augment the water supply for crops, livestock, and domestic use. With the mechanization of agriculture, its use has diminished, but it is still recommended for regions where the volume of rainfall is small and variable. The approach used depends primarily on the availability of equipment, the nature of the agricultural and livestock practices, and the type of soil.
|– This technology requires minimal additional labor.
– It offers flexibility of implementation; furrows can be constructed before or after planting.
– Rainwater harvesting allows better utilization of rainwater for irrigation purposes, particularly in the case of inclined raised beds.
– Rainwater harvesting is compatible with agricultural best management practices, including crop rotation.
– It provides additional flexibility in soil utilization.
– Permeable in situ rainwater harvesting areas can be used as a method of artificially recharging groundwater aquifers.
|– In situ rainwater harvesting cannot be implemented where the slope of the land is greater than 5%.
– It is difficult to implement in rocky soils.
– Areas covered with stones and/or trees need to be cleared before implementation.
– The additional costs incurred in implementing this technology could be a factor for some farmers.
– It requires impermeable soils and low topographic relief in order to be effective.
– The effectiveness of the storage area can be limited by evaporation that tends to occur between rains.
Surface water – general
Rainwater that is not captured directly, used by agriculture, or absorbed into the ground becomes surface water. Surface water harvesting includes all systems that collect and conserve surface runoff after a rainstorm or in intermittent streams, rivers, or wetlands for storage in open ponds and reservoirs. This can provide water for direct household use (treatment is generally required), irrigation, livestock, and aquaculture. Storage can also be the goal of collecting surface water, whether through open reservoirs or direct infiltration to aquifers below ground. Storing water in an aquifer conserves water better as it prevents evaporation, unlike open reservoir systems.
Climate change considerations
Cement made for water collecting structures, in a time of drought, can be made poorly due to less (or polluted) water used in the cement-making process. Higher heat from climate change will increase evaporation rates in reservoirs, or floods may damage infrastructure and increase runoff volumes. These effects and more are listed and tips are given to adapt the water system to climate change conditions.
|Various Types of Surface rainwater harvesting|
Groundwater recharge – general
Groundwater recharge is the enhancement of natural ground water supplies using man-made conveyances such as infiltration basins, trenches, dams, or injection wells. Aquifer storage and recovery (ASR) is a specific type of groundwater recharge practiced with the purpose of both augmenting ground water resources and recovering the water in the future for various uses.
Climate change considerations
- More storage capacity needed to overcome seasonal dry periods and to reduce floods.
- Higher rainfall intensities may exceed infiltration capacities. Create storage, enhanced infiltration or artificial recharge.
- Lower rainfall results in the need for transport and storage of water from other areas.
- Changes in vegetation will cause changes in evapotranspiration, surface runoff, erosion and sediment transport/deposition. This requires water and soil conservation measures, like terracing.
Fog and dew collection
Fog collection (or fog harvesting) is an innovative, environmentally appropriate, socially beneficial and economically viable use of fog, rain and dew as sustainable water resources for people in arid regions of developing countries. Fog is composed of enormous numbers of tiny water droplets. The wind blown droplets can be collected by a plastic mesh. Typical fog harvesting in a well selected desert environment would be 5 liters of water per square meter of mesh per day.
Dew harvesting (or dew collection) is simply taking advantage of water vapor in the atmosphere to harvest clean and potable water through condensation, a passive process that allows water particles to return to the earth in a pure form. Dew harvesting has been practiced by humanity as far back as ancient times, in areas where rainfall and groundwater resources are scarce. When there is any humidity at all in the air and there is a surface that is cool enough to provoke condensation, dew will condense on that surface until the humidity is gone. Vegetation in desert regions have developed modifications that allow them to collect their own humidity from the air, for example, and through efforts of reforestation in desert regions this technology has advanced abundantly around the world.
Courtesy : Akvopedia.org