Trilingual World Observatory: italiano, english, română. GLOBAL NEWS & more... di Redazione
\\ Home Page : Storico : en - Science and Society (invert the order)
Di seguito gli interventi pubblicati in questa sezione, in ordine cronologico.
By Admin (from 30/04/2011 @ 20:35:20, in en - Science and Society, read 13509 times)

Marijuana plants are either male or female . The male Marijuana plants produce pollen which pollinates the flowers  of  the  female  Marijuana plant, which once pollenized, produce seeds . If the female Marijuana plant  isn't  pollenized  (if  there  are  no  male  Mariuana plants  nearby  producing pollen), the flower/buds continue to develop and produce THC. Female Marijuana plants  which  are  not  pollenized  are  referred  to  as sinsemilla (without seeds). Usually 30-50% of the Marijuana plants are male.

What's the Difference you ask?

Males are often, but not always, tall with stout stems ,  sporadic  branching  and  few  leaves.  Males  are  usually  harvested except those used for breeding,  after  their  sex  has  been  determined,  but  before  the  pollen  is  shed.  When  harvesting, especially if close to females, cut the Marijuana plant off at the base, taking  care  to  shake  the  male  as  little  as  possible.  This  helps prevent any accidental pollination by an unnoticed, open male flower.

When a male enters the stage of flower development, the tips  of  the  branches  where  a  bud  would  develop  will  start  to grow what looks like a little bud (little balls) but it will have no white hairs coming  out  of  it.  Females  will  have  no  balls  and will have small white hairs. Read More about Male marijuana plants.

Male marijuana plant 


Cannabis in temperate climates begin to show his sexual identity by the end of July (end of January in the southern hemisphere) in different dates according to the varieties, Marijuana being the resinous flower of female cannabis plants intended for seed production, in absence of pollen buds turns out pure sensimilla weed and is gentle and sweet to smoke.

It is very important to get rid of male plants on time, as they are unwanted pollen carriers. By the early flowering stage male cannabis, if compared to female's, shows quite a different structure but the characteristic excrescencies would be the sex indicator this are called primordia and will emerge by the side of the third or fourth internodes in the main stem.

Female cannabis are completely revealed when the characteristic "V" shaped pistils become visible, all this to a close observation. Outdoors males will uncover themselves approximately three weeks before the females, indoors sexing of both males and females happens within a week to ten days according to the variety.

Female marijuana plant 


We've heard of urban legends about environmental conditions, age of seeds, added chemicals and even lunar stages having an influence on sexual differentiation of Cannabis; you might take note of those suggestions as personal communications, but a good handbook or an internet surf works the best if you lack in experience when sexing.

What is a Hermaphrodite plant?
An hermaphrodite, or hermie, is a Marijuana plant of one sex that develops the sexual organs of the other sex. Most commonly, a flowering female  Marijuana plant  will  develop  staminate flowers, though the reverse is also true. Primarily male hermaphrodites are  not  as well  recognized  only  because  few   growers  let  their  males  reach  a  point  of flowering where the pistillate would be expressed.

Hermaphrodites are generally viewed with disfavor. First, they  will  release  pollen and ruin a sinsemelia crop, pollinating themselves and all of the other females in the room. Second, the resulting seeds are worthless, because hermaphrodite  parents tend to pass on the tendency to their offspring.

Please note that occassionally specious staminate  flowers  will  appear  in  the  last  days  of  flowering  of  a  female  Marijuana plant. These do not drop pollen and their appearance is not considered evidence of deleterious hermaphroditism.

Hermaphrodite marijuana plant 


Here's an image of a hermaphrodite, specifically a female Marijuana plant with staminate flowers.


By Admin (from 30/04/2011 @ 14:00:06, in en - Science and Society, read 1821 times)

An Oxford University study suggests that people living in countries with 'free market' regimes are more likely to become obese due to the stress of being exposed to economic insecurity.

The researchers believe that the stress of living in a competitive social system without a strong welfare state could be causing people to overeat. According to the study published in the latest issue of the journal Economics and Human Biology, Americans and Britons are much more likely to be obese than Norwegians and Swedes.

Oxford researchers compared 11 affluent countries and found that those with a liberal market regime (strong market incentives and relatively weak welfare states) experienced one-third more obesity on average. Their analysis of nearly 100 surveys, carried out between 1994 and 2004, revealed that the highest prevalence of obesity reported in a single survey was in the United States where one-third of the population was classed as obese. By contrast, Norway had the lowest prevalence of obesity in a single survey at just five per cent.

The study compared 'market-liberal' countries (United States, Britain, Canada and Australia) with seven relatively affluent European countries that have systems that traditionally offer stronger social protection (Finland, France, Germany, Italy, Norway, Spain and Sweden). It concludes that economic security plays a significant role in determining levels of obesity. Countries with higher levels of job and income security were associated with lower levels of obesity.

In the past, the rise of obesity in affluent societies has frequently been attributed to the ready supply of cheap, accessible, high-energy, pre-processed food in fast food outlets and supermarkets. This cause is known by researchers as the 'fast food shock'. Oxford researchers measured the impact of fast food by using a price index, constructed by The Economist magazine*, showing the international variation in the cost of the McDonald's Big Mac hamburger. They found that the availability of fast food may not be as significant as previously thought, as they calculated it had half as much an effect on the prevalence of obesity as the effects of economic insecurity.

Lead author Professor Avner Offer, Chichele Professor of Economic History at the University of Oxford, said: 'Policies to reduce levels of obesity tend to focus on encouraging people to look after themselves but this study suggests that obesity has larger social causes. The onset and increase of large-scale obesity began during the 1980s, and coincided with the rise of market-liberalism in the English-speaking countries.

'It may be that the economic benefits of flexible and open markets come at a price to personal and public health which is rarely taken into account. Basically, our hypothesis is that market-liberal reforms have stimulated competition in both the work environment and in what we consume, and this has undermined personal stability and security.'

The Oxford research team based this study on observations in academic literature about animal behaviour. Animals, both in captivity and in the wild, have been found to increase their food intake when they are faced with uncertainty about their future food supply.

These latest findings suggest that obesity in affluent societies is a response to the stress of economic insecurity. The researchers found that the effects of economic security were considerably greater in causing obesity than other factors measured (the existence of a market-liberal regime; inequality, the price of fast food, and the passage of time).

'Obesity under affluence varies by welfare regimes: The effect of fast food, insecurity, and inequality' is by Avner Offer, Rachel Pechey and Stanley Ulijaszek.

Source: ScienceDaily

By Admin (from 29/04/2011 @ 14:00:44, in en - Science and Society, read 1623 times)

The world has waited with bated breath for three decades, and now finally a group of academics, engineers, and math geeks have finally found the magic number. That number is 20, and it's the maximum number of moves it takes to solve a Rubik's Cube.

Known as "God's Number", the magic number required about 35 CPU-years and a good deal of man-hours to solve. Why? Because there's 43,252,003,274,489,856,000 possible positions of the cube, and the computer algorithm that finally cracked God's Algorithm had to solve them all. (The terms "God's Number/Algorithm are derived from the fact that if God was solving a Cube, he/she/it would always do it in the most efficient way possible.)

A full breakdown of the history of God's Number as well as a full breakdown of the math is available here, but summarily the team broke the possible positions down into sets, then drastically cut the number of possible positions they had to solve for through symmetry (if you scramble a Cube randomly and then turn it upside down, you haven't changed the solution).

They then borrowed some computing time from Google (one of the principals is an engineer there) and burned about 35 core-years to solve all the possible positions. The number 20 has been the lower limit for God's Number for more than a decade, but the team was finally able to whittle away at the upper limit (which was trimmed back to 22 in 2008).

So far the algorithm has identified some 12 million distance-20 positions, though there are definitely many more than that. Click on this link if you want to see what some of the hardest positions are, and how they exactly tackled this problem.

Source: PopSci


The instability of large, complex societies is a predictable phenomenon, according to a new mathematical model that explores the emergence of early human societies via warfare. Capturing hundreds of years of human history, the model reveals the dynamical nature of societies, which can be difficult to uncover in archaeological data.

The research, led Sergey Gavrilets, associate director for scientific activities at the National Institute for Mathematical and Biological Synthesis and a professor at the University of Tennessee-Knoxville, is published in the first issue of the new journal Cliodynamics: The Journal of Theoretical and Mathematical History, the first academic journal dedicated to research from the emerging science of theoretical history and mathematics.

The numerical model focuses on both size and complexity of emerging "polities" or states as well as their longevity and settlement patterns as a result of warfare. A number of factors were measured, but unexpectedly, the largest effect on the results was due to just two factors – the scaling of a state's power to the probability of winning a conflict and a leader's average time in power. According to the model, the stability of large, complex polities is strongly promoted if the outcomes of conflicts are mostly determined by the polities' wealth or power, if there exist well-defined and accepted means of succession, and if control mechanisms within polities are internally specialized. The results also showed that polities experience what the authors call "chiefly cycles" or rapid cycles of growth and collapse due to warfare.

The wealthiest of polities does not necessarily win a conflict, however. There are many other factors besides wealth that can affect the outcome of a conflict, the authors write. The model also suggests that the rapid collapse of a polity can occur even without environmental disturbances, such as drought or overpopulation.

By using a mathematical model, the researchers were able to capture the dynamical processes that cause chiefdoms, states and empires to emerge, persist and collapse at the scale of decades to centuries.

"In the last several decades, mathematical models have been traditionally important in the physical, life and economic sciences, but now they are also becoming important for explaining historical data," said Gavrilets. "Our model provides theoretical support for the view that cultural, demographic and ecological conditions can predict the emergence and dynamics of complex societies."

Source: EurekAlert

By Admin (from 24/04/2011 @ 08:00:22, in en - Science and Society, read 2134 times)

Having a computer that can read our emotions could lead to all sorts of new applications, including computer games where the player has to control their emotions while playing. Thomas Christy, a Computer Science PhD student at Bangor University is hoping to bring this reality a little nearer by developing a system that will enable computers to read and interpret our emotions and moods in real time.

Tom’s work focuses on ‘hands-on’ pattern recognition and machine learning. His supervisor Professor Lucy Kuncheva at the University’s School of Computer Science is a world expert in pattern recognition and classification, specifically in classifier ensembles. A classifier ensemble is a group of programmes that independently analyse data and decide to which label or group the data belongs. The final decision is reached by a ‘majority’ or consensus, and is often more accurate than individual classifier decisions.

The plan is to combine brain wave information collected from a single electrode that sits on the forehead as part of a ‘headset’, a skin conductance response (which will detect tiny changes in perspiration as first indicators of stress) and a pulse signal, reflecting the wearer’s heart rate. This information will form the data fed into a classifier ensemble set to determine which emotion a person is experiencing.

“I am particularly interested in developing a real-time ‘mood sensing’ device. It will combine already existing biometric detection devices into a lightweight portable system that will be able to perceive and indicate a person’s mood and level of stress and anxiety,” said Tom.

Tom is aiming to pioneer classification software techniques that will allow players’ emotions to be identified within the gaming environment. This will open up new and exciting markets for the gaming industry. New games can be created; where players must control their feelings in order to advance within their virtual environment.

“This area of emotional study is fast becoming an important part of research within Computer Science and is known as Affective Computing,” explained Prof. Lucy Kuncheva.

There are many other possible applications for this type of technology, for example marketing to determine customer preferences and brand effectiveness, monitoring anxiety levels of prospective soldiers during military training, providing instant neuro-feedback to combat addictive behaviours; the list is seemingly endless.

Tom is working in close collaboration with the Bangor University’s Schools of Electronic Engineering and Psychology and has had talks with Massachusetts Institute of Technology (MIT) in Boston, USA in pursuit of his research. He is looking for industrial collaborators and innovators who would be interested in this area.

Source: PhysOrg

By Admin (from 23/04/2011 @ 08:00:50, in en - Science and Society, read 1854 times)

A new scientific discovery could have profound implications for nanoelectronic components. Researchers from the Nano-Science Center at the Niels Bohr Institute, University of Copenhagen, in collaboration with Japanese researchers, have shown how electrons on thin tubes of graphite exhibit a unique interaction between their motion and their attached magnetic field – the so-called spin. The discovery paves the way for unprecedented control over the spin of electrons and may have a big impact on applications for spin-based nanoelectronics. The results have been published in the prestigious journal Nature Physics.

Carbon is a wonderfully versatile element. It is a basic building block in living organisms, one of the most beautiful and hardest materials in the form of diamonds and is found in pencils as graphite. Carbon also has great potential as the foundation for computers of the future as components can be produced from flat, atom thin graphite layers, observed for the first time in the laboratory in 2004 – a discovery which elicited last year's Nobel Prize in Physics.

In addition to a charge all electrons have an attached magnetic field – a so-called spin. One can imagine that all electrons carry around a little bar magnet. The electron's spin has great potential as the basis for future computer chips, but this development has been hindered by the fact that the spin has proved difficult to control and measure.

In flat graphite layers the movement of the electrons do not affect the spin and the small bar magnets point in random directions. As a result, graphite was not an obvious candidate for spin based electronics at first.

New spin in curved carbon

"However, our results show that if the graphite layer is curved into a tube with a diameter of just a few nanometers, the spin of the individual electrons are suddenly strongly influenced by the motion of the electrons. When the electrons on the nanotube are further forced to move in simple circles around the tube the result is that all the spins turn in along the direction of the tube", explain the researchers Thomas Sand Jespersen and Kasper Grove-Rasmussen at the Nano-Science Center at the Niels Bohr Institute.

It has previously been assumed that this phenomenon could only happen in special cases of a single electron on a perfect carbon nanotube, floating freely in a vacuum – a situation that is very difficult to realize in reality. Now the researchers' results show that the alignment takes place in general cases with arbitrary numbers of electrons on carbon tubes with defects and impurities, which will always be present in realistic components.

The interaction between motion and spin was measured by sending a current through a nanotube, where the number of electrons can be individually controlled. The two Danish researchers explain that they have further demonstrated how you can control the strength of the effect or even turn it off entirely by choosing the right number of electrons. This opens up a whole range of new possibilities for the control of and application of the spin.

Unique Properties

In other materials, like gold for example, the motion of the electrons also have a strong influence on the direction of the spin, but as the motion is irregular, one cannot achieve control over the spin of the electrons. Carbon distinguishes itself once again from other materials by possessing entirely unique properties – properties that may be important for future nanoelectronics.


By Admin (from 22/04/2011 @ 08:00:12, in en - Science and Society, read 2339 times)

Just 13 days after receiving a pioneering larynx transplant, a Californian woman was able to speak her first words in a decade. Her own larynx was permanently damaged by an operation 11 years ago.

The first combined larynx and thyroid transplant was performed in 1998, but in the latest operation Brenda Charett Jensen of Modesto, California, received a section of trachea too. The feat, which took 18 hours, was performed last October at the Medical Center of the University of California, Davis, but announced only yesterday.

The transplant also works far better than the first because more of the donated organs' nerves have been plugged into the 52-year-old woman's own nervous system. This enables her to move muscles that control speaking by moving the vocal cords, and others that will eventually allow her to swallow again, once she relearns how to do it.

"It is a miracle," says Jensen. "I'm talking, talking, talking, which just amazes my family and friends." The sound of her voice is her own, rather than that of the donor.

Her own voice again

Jensen lost her speech 11 years ago through complications during surgery that blocked her airway. The blockage stopped her larynx working, so for years she has communicated with a handheld voice synthesiser. That operation also left her breathing dependent on a tracheotomy – a tube inserted into her windpipe. With the new trachea, the hope is that she should also be able to breathe normally and dispense with the tracheotomy.

One of the reasons that Jensen was chosen was that she was already on immunosuppressive drugs because of a previous kidney-pancreas transplant, reducing the risk of organ rejection.

Led by surgeon Gregory Farwell, the team transplanted the larynx, thyroid and trachea of a woman who died in an accident . The thyroid has to be transplanted too, because it supplies blood to the larynx.

Farwell and his colleagues plumbed numerous blood vessels from the donated organs into Jensen's own, and also reconnected five major nerves to maximise her control over the muscle tissue that came with the transplant.

"The first larynx transplant only reconnected three nerves," says Martin Birchall of University College London, who served as chief scientific adviser to the team, specialising in reconnection of the nerves. "Here, we've done five nerves with the intention of restoring much more laryngeal function than the original, and eventually getting rid of the tracheotomy."

Rapid progress

Birchall said that although the man who received the original larynx transplant at the Cleveland Research Clinic in Ohio in 1998 is doing well and has recovered some speech, he still has a tracheotomy. His vocal cords have never moved, whereas Jensen's were moving in just a fortnight. "We've already seen much quicker progress in speech," says Birchall.

The breakthrough is the latest to exploit rapid improvements in microsurgical techniques since the first face transplant in 2005. The increasingly ambitious use of more complex transplants including muscles, nerves and bones has also highlighted the greater functionality that this allows the recipient.

Birchall believes that recipients will benefit even more if their own stem cells are extracted and used to coat donated organs chemically stripped of all donor cells. Because all that's then left of the donated organ is a "scaffold" of the protein collagen, it can be covered with the recipient's own cells and transplanted into their body with no fear of rejection.

In 2008, Birchall was part of a team that demonstrated this can be done by performing the world's first trachea transplant.

Complex challenge

Birchall told New Scientist that such an approach would be possible with the larynx, but unlike the trachea – which is simply a tube – a recoated larynx would also have to include artificially constructed muscles and blood vessels because of its much more complex function.

"It's much more complex than the trachea, but we do have ways to address these things," says Birchall. "Regenerative medicine using stem cells is now moving at a furious pace, and the airways and plumbing systems are at the forefront," he says.

Hear and see her voice here.

Source: NewScientist

By Admin (from 20/04/2011 @ 14:00:48, in en - Science and Society, read 2382 times)

Although modern prosthetic devices are more lifelike and easier for amputees to control than ever before, they still lack a sense of touch. Patients depend on visual feedback to operate their prostheses – they know that they’ve touched an object when they see their prosthetic hand hitting it. Without sensation, patients cannot accurately judge the force of their grip or perceive temperature and texture.

Todd Kuiken, a professor at Northwestern University and director of the Neural Engineering Center for Artificial Limbs at the Rehabilitation Institute of Chicago, has led the development of a new technique known as targeted reinnervation, which can help amputees control motorized prosthetic arms. He and his team now hope to extend the applications of targeted reinnervation to help patients regain sensory capabilities.

In targeted reinnervation, the motor nerves of a nearby target muscle (usually the chest) are deactivated. Then the residual motor nerves at the end of an amputated arm are transplanted from the stump to the chest. The nerves rewire themselves and grow into the chest muscle. Since amputation of a limb does not prevent the nerves left in the residual limb from signaling, the reinnervation procedure simply gives the signals a new destination.

After the procedure, when a person thinks about moving a muscle in the missing arm or hand, the chest muscle twitches. Electrodes pick up these signals and pass them on to a motorized prosthetic arm, allowing patients to control multiple motor functions like the simultaneous movement of both the elbow and hand to throw a ball.

The regrowth of sensory nerves after this procedure was discovered by accident. The first patient to undergo targeted reinnervation told Kuiken and his other doctors about an interesting sensation he experienced: when someone touched the area of his chest where his nerves had regrown, he felt as if someone was touching his missing hand. The sensory nerves from his arm stump had reinnervated the skin above his chest muscle. He was experiencing touch to the reinnervated skin as being applied to his missing limb. It turned out that sensory reinnervation such as this was common following the procedure.

Kuiken and his colleagues are currently exploring how to take advantage of sensory reinnervation to build prosthetic arms with sensors on the fingers that can transfer touch information from the prosthetic to the chest, allowing patients to “feel” what they are touching with their prostheses.

The next step is to figure out the mechanisms that guide reinnervation, with the hope of someday being able to direct the regrowth of nerves for more refined results. To better understand how sensory reinnervation affects brain reorganization, Kuiken and his colleague Paul Marasco examined the brains of rats after amputation and targeted reinnervation. In this experiment, published in The Journal of Neuroscience, Marasco and Kuiken looked at how the somatosensory cortex, the brain area that receives and processes input from sensory organs, changed in rats following forelimb amputation with and without the targeted reinnervation procedure.

One group of rats underwent forelimb amputation and then targeted reinnervation, while another group of rats underwent only the amputation. The rats that did not undergo targeted reinnervation effectively had the input between the cortex and the forepaw silenced. After thirteen weeks of recovery, the experimenters recorded brain activity in the primary somatosensory cortex of all the animals. Marasco and Kuiken were especially interested in the region known as the forelimb barrel subfield, which would normally process touch input from the amputated forepaw.

As expected, the rats that underwent amputation without targeted reinnervation showed an almost complete silencing of brain activity in the forelimb barrel subfield. The receptive fields for the few active areas in this region were located on the residual shoulder.

In contrast, the rats that underwent targeted reinnervation showed extensive activity in the forelimb barrel subfield. The receptive fields for the active sites in these rats were small and densely clustered on the far end of the stump, and differed in proportion from the large and diffuse receptive fields observed on the residual limb of the amputation-only rats. It appeared that the sensory input from the reinnervated skin was processed within the cortical representation of the missing forepaw.

This helps explain why Kuiken’s earlier human patient reported feeling a touch on his chest as occurring on his missing hand. His somatosensory cortex, in particular the area devoted to the missing limb, had reorganized to accommodate the new sensory input. Sensations from the skin on his chest were being processed within the hand representation area of his somatosensory cortex.

Further somatosensory reorganization was evident in the rats. In most of the animals that underwent targeted reinnervation following amputation, there were regions of the forelimb barrel subfield (called dual receptive fields) that were responsive to both the stump and other regions of the body (the whiskers, lower lip, and hindlimb). The presence of dual receptive fields in these rats, but not in the amputation-only rats, suggests that the adjacent brain areas expanded into the denervated regions following the amputation. The sharing of space allowed those sensory nerves to keep transmitting signals, even after amputation.

Marasco and Kuiken’s results provide important insights into the sensory phenomena observed in human targeted reinnervation patients. The reorganization of somatosensory cortex in rats following the procedure supports the hypothesis that the reinnervated skin is able to act as a direct line of communication from a prosthetic device to the regions of the brain that process hand and limb sensations. This is likely the mechanism by which targeted reinnervation provides sensation that is perceived as coming from an amputated limb.

Ultimately, Marasco and Kuiken hope that this experiment will contribute to the building of better prosthetic limbs. Motorized prostheses that also provide sensory feedback have the potential to be more effective, capable of more functions, and easier to manipulate. Most importantly, they would not only function like a real human arm but also feel like one, allowing the prosthetic to be integrated more naturally into the patient’s self image.

Source: Technology Review

By Admin (from 19/04/2011 @ 14:00:51, in en - Science and Society, read 1500 times)

There's a reason why Hollywood makes movies like Arachnophobia and Snakes on a Plane: Most people are afraid of spiders and snakes. A new paper published in Current Directions in Psychological Science, a journal of the Association for Psychological Science, reviews research with infants and toddlers and finds that we aren't born afraid of spiders and snakes, but we can learn these fears very quickly.

One theory about why we fear spiders and snakes is because so many are poisonous; natural selection may have favored people who stayed away from these dangerous critters. Indeed, several studies have found that it's easier for both humans and monkeys to learn to fear evolutionarily threatening things than non-threatening things. For example, research by Arne Ohman at the Karolinska Institute in Sweden, you can teach people to associate an electric shock with either photos of snakes and spiders or photos of flowers and mushrooms—but the effect lasts a lot longer with the snakes and spiders. Similarly, Susan Mineka's research (from Northwestern University) shows that monkeys that are raised in the lab aren't afraid of snakes, but they'll learn to fear snakes much more readily than flowers or rabbits.

The authors of the Current Directions in Psychological Science paper have studied how infants and toddlers react to scary objects. In one set of experiments, they showed infants as young as 7 months old two videos side by side—one of a snake and one of something non-threatening, such as an elephant. At the same time, the researchers played either a fearful voice or a happy voice. The babies spent more time looking at the snake videos when listening to the fearful voices, but showed no signs of fear themselves.

"What we're suggesting is that we have these biases to detect things like snakes and spiders really quickly, and to associate them with things that are yucky or bad, like a fearful voice," says Vanessa LoBue of Rutgers University, who cowrote the paper with David H. Rakison of Carnegie Mellon University and Judy S. DeLoache of the University of Virginia.

In another study, three-year-olds were shown a screen of nine photographs and told to pick out some target item. They identified snakes more quickly than flowers and more quickly than other animals that look similar to snakes, such as frogs and caterpillars. Children who were afraid of snakes were just as fast at picking them out than children who hadn't developed that fear.

"The original research by Ohman and Mineka with monkeys and adults suggested two important things that make snakes and spiders different," LoBue says. "One is that we detect them quickly. The other is that we learn to be afraid of them really quickly." Her research on infants and young children suggests that this is true early in life, too—but not innate, since small children aren't necessarily afraid of snakes and spiders.

Source: EurekAlert


Split-cycle engines have been around for some time but until now have never matched the fuel efficiency of traditional internal combustion engines. That is about to change, with the latest split-cycle engines from the Scuderi Group offering greater fuel efficiency and up to 80 percent reduction in NOx emissions and 50 percent reduction in CO2.

Split-cycle engines feature paired cylinders, so a four-cylinder engine has two sets of paired cylinders working together, with a crossover passage linking the two cylinders in each pair to each other. The four strokes of the engine are split into two groups, with the left cylinder handling intake and compression and the second handling combustion and exhaust. The Scuderi™ Air-Hybrid design adds an air storage tank and controls that allow it to recapture and store the energy lost as the engine operates.

The new design solves some of theproblems that have hampered previous split-cycle designs. The low volume breathing problem is solved by outward-opening pneumatic valves and a reduction in the clearance between the piston and cylinder head to under 1 mm, which means virtually 100 percent of the compressed air is pushed out of the cylinder.

The thermal efficiency problem of previous designs has been solved by adopting After Top Dead Center (ATDC) firing, which avoids losses caused by recompressing the gas. Firing ATDC is achieved by high pressure air entering the cylinder and resulting in massive turbulence. Firing ATDC is a cleaner burn that also dramatically reduces NOx emissions and improves fuel efficiency.

The Southwest Research Institute (SwRI) has been testing a 1-liter, two-cylinder engine for almost a year. The preliminary results suggest a 30-36 percent increase in fuel efficiency for the naturally aspirated Scuderi™ Air-Hybrid and a 25 percent increase for the base model. The test engine generates 135 horsepower at 6,000 RPM, which is similar to results of bigger and more fuel-hungy cars.
Sal Scuderi, son of the inventor Carmelo Scuderi who died in 2002, said he expected efficiencies should improve still further as the designs are fine-tuned and new simulations are run with the engines in different vehicles.

The Scuderi engine can be built using conventional parts and minimal re-tooling is necessary, which makes it easier for manufacturers to adopt it. Scuderi says the technology should be licensed and on the road within three years.

Source: PhysOrg

Ci sono 4140 persone collegate

< maggio 2021 >

en - Global Observatory (605)
en - Science and Society (594)
en - Video Alert (346)
it - Osservatorio Globale (503)
it - Scienze e Societa (555)
it - Video Alerta (132)
ro - Observator Global (399)
ro - Stiinta si Societate (467)
ro - TV Network (149)
z - Games Giochi Jocuri (68)

Catalogati per mese - Filed by month - Arhivate pe luni:

Gli interventi piů cliccati

Ultimi commenti - Last comments - Ultimele comentarii:
Hi, it's Nathan!Pretty much everyone is using voice search with their Siri/Google/Alexa to ask for services and products now, and next year, it'll be EVERYONE of your customers. Imagine what you are ...
15/01/2019 @ 17:58:25
By Nathan
Now Colorado is one love, I'm already packing suitcases;)
14/01/2018 @ 16:07:36
By Napasechnik
Nice read, I just passed this onto a friend who was doing some research on that. And he just bought me lunch since I found it for him smile So let me rephrase that Thank you for lunch! Whenever you ha...
21/11/2016 @ 09:41:39
By Anonimo


15/05/2021 @ 12:27:56
script eseguito in 794 ms