Policymakers around the world have been beguiled by the prospects of Hyperloop technology providing a paradigm shift in inter-city transport, potentially at the expense of rail investment. However, Gareth Dennis sounds a note of caution about the technical and commercial hurdles facing this ‘fifth mode of transport’.,Gareth Dennis is a Permanent Way Engineer for an international design consultancy. Based in York, he leads the local section of his professional institution, as well as being a lecturer in track systems at the UK’s National College for High Speed Rail.The much-vaunted Hyperloop, sometimes described by its proponents as the ‘fifth mode of transport’, uses the premise of pods travelling through evacuated tubes to offer high speed inter-city transport. . The concept was first attributed to US-based technology entrepreneur Elon Musk, and independent backers are popping up across the globe, amid huge amounts of publicity.On paper, the concept is a clever one, extrapolating Newton’s First Law to remove as much air resistance as possible to reduce the required motive force to achieve the desired speeds. The technology itself is not revolutionary, simply comprising a pod elevated and driven forwards by magnetic levitation in a tube pumped to a near-vacuum.Some progress has been made by the various competing Hyperloop developers. Virgin Hyperloop One, for example, has built a 500 m ‘DevLoop’ test ring in the Nevada desert, where it has demonstrated the technological union of maglev and vacuum tube. Acceleration, top speed, the pressurised cabin environment and associated emergency arrangements are all very similar to those utilised in commercial air travel. But for all the attention lavished upon Hyperloop, there are fundamental problems that must be overcome before any commercial application is realistic.Straight, undergroundSteel wheel high speed rail can have a design speed of up to 400 km/h, and it is common for curves to be 10 km or more in radius. Whilst Hyperloop will probably permit tighter curves than a railway, it aspires to a design speed of up to 1 100 km/h.As with conventional railway alignments, Hyperloop will rotate the plane of its guideway as curvature increases to reduce the forces on passengers. Yet it seems unlikely that a guideway could be tilted enough to avoid a near-straight alignment, with inertial forces on passengers being comparable to those in a jet aircraft. This in turn is likely to mean the tubes would be underground in most applications.Switches pose another huge technological hurdle. Indeed, even after almost 200 years of railway development, these components still go wrong quite regularly. Passing trains impart huge forces on the underlying track, resulting in rapid degradation of the steelwork. The mechanism that moves the switch can be complex and cumbersome, while managing detection and the interface with the railway control system can also be challenging. In this context, it is fanciful to think Hyperloop developers could overcome these complex requirements first time around, not to mention at six or seven times the operating speed of the fastest steel wheel railway.The vacuum tube concept also throws up some technical gremlins. Thermal expansion effects on the tubes can be managed by using materials with a reduced thermal expansion coefficient and by constructing expansion joints between each tube segment. However, these expansion joints would have to be strong enough to withstand the pressures from the vacuum within, increasing their cost greatly.In an emergency, or in the case of a pump failure, the tube would have to be returned to atmospheric pressure: all this requires is a valve controlling the ingress of air. The problems start when the vacuum needs to be restored. With regular airlocks, you could not run a pod at speed from a vacuum into a section at atmospheric pressure. At 1 000 km/h, this would be akin to driving a car into a concrete block.But if pods have to sit and wait for the correct pressure conditions to be achieved mid-service, delays could be considerable: the Hyperloop One test tube needs 4 h to return to a vacuum over a 500 m alignment. Undoubtedly there will be more powerful pumps in any commercial specification, but this is still technology requiring radical development.Energy and capacityJapan’s Chuo Shinkansen maglev is likely to use approximately three times more energy per seat energy than steel wheel high speed rail. While Hyperloop’s vacuum tubes will remove almost all aerodynamic friction, reducing the motive power needed to reach and sustain high speed, there will be almost no aerodynamic drag, increasing the power required to slow the pods down. The likely power consumption of the pumps maintaining the vacuum conditions must be considered on top.Yet it is passenger capacity which is arguably the most fundamental challenge. Using the UK’s planned High Speed 2 as a benchmark, high speed rail capacity can be nearly 20 000 passengers per hour per direction, assuming 18 trains/h over a double track alignment, each with 1 100 seats. If a Hyperloop pod had 50 seats for example, then to match HS2’s capacity 400 pods would need to depart every hour at a 9 sec headway. Assuming the same number of seconds to alight from a Hyperloop pod as a train, 23 tubes would be needed to match HS2’s throughput.None of this is to dismiss entirely Hyperloop’s prospects. Indeed, the eager and exceptional minds in organisations like VHO will doubtless continue their quest for answers. But we should not yet claim that Hyperloop could replace steel wheel rail, which is far from the outdated mode some would assert. For the foreseeable future, Hyperloop is likely to remain a technological experiment meriting private backing, rather than public funding.
5G is expected to debut commercially in 2020. To do so, a great deal of research and standardization work needs to be done. Rohde & Schwarz has been helping developers identify potential technologies for accessing 5G mobile networks. At the 5G Global Summit, held in Busan, South Korea, on October 20 and 21, 2014, Rohde & Schwarz presented an extremely compact test setup for generating and analyzing signals up to 67 GHz. The test setup consisted of the R&S SMW200A high-end vector signal generator (up to 20 GHz), a harmonic mixer from subsidiary Radiometer Physics GmbH (RPG) and the R&S FSW67 high-end signal and spectrum analyzer. This test setup enables users to evaluate potential new physical air interface technologies for future 5G networks, helping to drive the development of components, antennas and chipsets for future base stations and wireless devices.The R&S SMW200A features two integrated RF paths up to 20 GHz and a wideband I/Q modulator with a bandwidth of 2 GHz. The internal baseband section with an I/Q modulation bandwidth of 160 MHz supports all digital communications standards, with the option to add fading simulators as needed. The integrated ARB generator can be used to generate high-quality, complex, digitally modulated waveforms. In combination with RPG harmonic mixers, it is possible to generate signals for all relevant frequencies, for example into the E band (60 GHz to 90 GHz). The R&S FSW67 analyzes signals in the frequency range up to 67 GHz at an analysis bandwidth of 500 MHz and offers a 2 GHz analog IF output for further analysis of broadband signals, making it ideal for the challenging T&M tasks associated with the 5G development phase.5G will not simply extend existing LTE/LTE-Advanced systems, it will also create a new technological framework to support a variety of different application scenarios and a sharp increase in the number of wireless devices. One way to meet the demand for more system capacity and higher data rates is to extend the spectrum into the millimeter-wave range. The up to 67 GHz test solution presented by Rohde & Schwarz meets this requirement.More information on R&S’ contributions and research towards 5G can be seen here: www.rohde-schwarz.com/ad/press/5g
He will be filling the open seat left by former Chair Karl Johnstone who resigned earlier this year when he was told he would not be reappointed in July. FacebookTwitterEmailPrintFriendly分享Robert Ruffner has been appointed by Governor Bill Walker to the open seat on the Board of Fisheries. Ruffner: “I have a pretty solid education in math and statistics, I’ve done numerical modeling and all of those have been around geology and physical processes like modeling rivers and how they move, but those techniques and using statistics are readily transferable to the biological world. So I think that I will have a good understanding and know what questions to ask when it comes to looking at data sets, whether they are biological data sets or economic data sets.” He spoke with us about the perks he will bring to the board. Ruffner’s appointment must be approved by the Legislature. Walker’s original appointment to the seat was local drifter Roland Maw who withdrew his name after a criminal investigation involving Maw hunting in Montana began. Ruffner has been the Executive Director of the Kenai Watershed Forum for the past 18 years although in January he announced his plans to retire after he trains a replacement.
AD Quality Auto 360p 720p 1080p Top articles1/5READ MORECoach Doc Rivers a “fan” from way back of Jazz’s Jordan Clarkson at N.Y. Islanders 1 Martin St. Louis’ short-handed breakaway goal with 4:57 left gave the Lightning the victory and spoiled a brilliant goaltending performance by the Islanders’ Garth Snow, who made 41 saves. Philadelphia 1, at Boston 0 Antero Niittymaki made 27 saves for his second career shutout, and Jeff Carter scored the lone goal to lead the Flyers, who improved to 5-1 on an 11-game trip. at Calgary 3, Chicago 2 Matthew Lombardi scored with 7:04 left to give the Flames their third straight victory. Calgary moved within three points of Detroit for first place in the Western Conference. at St. Louis 4, Vancouver 1 Mike Sillinger had two goals and an assist as the Blues won for just the fifth time at home this season. The Canucks lost for the seventh time in their past eight games. 160Want local news?Sign up for the Localist and stay informed Something went wrong. Please try again.subscribeCongratulations! You’re all set! Bryan McCabe spoiled Sidney Crosby’s NHL debut in Canada, scoring 1:02 into overtime to lead the Maple Leafs to their season-high sixth straight win. Tampa Bay 2, at Toronto 3, Pittsburgh 2 (OT)