The political origins of platform economy regulations. Understanding variations in governing Airbnb and Uber across cities in Switzerland

In the past decade, digital platforms have entrenched themselves within key urban sectors, opening the way for radical changes in traditional industries. Along with new opportunities for city residents, globally operating platforms such as Airbnb and Uber also raised specific challenges, sparking calls for adequate responses by city governments around the world. The aim of this paper is to explain the diversity of regulations across cities. Holding constant national factors, we conducted comparative case studies in six Swiss cities (Zurich, Geneva, Davos, Montreux, Aarau, and Neuchâtel) to investigate political processes leading to local regulations of Airbnb and Uber. Four crucial factors shape regulatory trajectories. First, intensity of platform-related issues in cities is key in shaping the stringency of regulatory responses. Second, grassroots and political mobilization plays a role: where these issues become politically salient, regulations are stricter. Third, the inscription of platform-related issues on a city's institutional agenda tends to produce stricter regulatory responses. Finally, local governments tend to adopt a stricter control over platforms in cities where relevant urban sectors are already highly regulated. We conclude that the varying stringency of governmental responses to the platform economy lays in the dynamics of politicization from which they emerged

Autonomous space processor for orbital debris

This work continues to develop advanced designs toward the ultimate goal of a GETAWAY SPECIAL to demonstrate economical removal of orbital debris utilizing local resources in orbit. The fundamental technical feasibility was demonstrated last year through theoretical calculations, quantitative computer animation, a solar focal point cutter, a robotic arm design and a subscale model. During this reporting period, several improvements are made in the solar cutter, such as auto track capabilities, better quality reflectors and a more versatile framework. The major advance has been in the design, fabrication and working demonstration of a ROBOTIC ARM that has several degrees of freedom. The functions were specifically tailored for the orbital debris handling. These advances are discussed here. Also a small fraction of the resources were allocated towards research in flame augmentation in SCRAMJETS for the NASP. Here, the fundamental advance was the attainment of Mach numbers up to 0.6 in the flame zone and a vastly improved injection system; the current work is expected to achieve supersonic combustion in the laboratory and an advanced monitoring system

Optical extinction in a single layer of nanorods

We demonstrate that almost 100 % of incident photons can interact with a monolayer of scatterers in a symmetrical environment. Nearly-perfect optical extinction through free-standing transparent nanorod arrays has been measured. The sharp spectral opacity window, in the form of a characteristic Fano resonance, arises from the coherent multiple scattering in the array. In addition, we show that nanorods made of absorbing material exhibit a 25-fold absorption enhancement per unit volume compared to unstructured thin film. These results open new perspectives for light management in high-Q, low volume dielectric nanostructures, with potential applications in optical systems, spectroscopy, and optomechanics

Sobre la información de amplitud transmitida por el campo sísmico ambiental

The use of the ambient seismic field (ASF) to extract Earth’s response has received significant attention in the last several years. Multiple studies demonstrate the utility of the ASF for estimating high-resolution velocity models in various locations. In this paper, we discuss the amplitude information carried by the ASF. Amplitude information includes both amplification effects due to elastic structure, such as low velocity sedimentary basins, and attenuation effects in the crust and upper mantle or even in buildings. As has been suggested by other authors, amplitude measurements may be biased due to nonuniformities in ambient field excitation; however, we find very similar and stable results for different time intervals for both amplification and attenuation, suggesting that this bias may not be as large as feared. We conclude that valuable amplitude information can be recovered from the ASF through careful processing. Amplitude measurements may be particularly valuable due to the enhanced sensitivity of attenuation to fluids and/or temperature fluctuations. 2011 Acade´mie des sciences. Published by Elsevier Masson SAS. All rights reserve

Nannoplankton records obtained from Chesapeake Bay cruises of R/V Pathfinder and R/V Observer : January 1960 - January 1961

Also part of series: Virginia Fisheries Laboratory special scientific report ; no. 21

Distribution of ammonia nitrogen in the lower York River, Virginia : Spring, 1961

Also part of series: Virginia Fisheries Laboratory special scientific report ; no. 25

Fast pyrolysis bio-oil production in an entrained flow reactor pilot

Bio-oil produced from biomass fast pyrolysis could constitute an alternative to fossil liquid fuels, especially to be combusted for local district heating. So far, only few studies have dealt with bio-oil production by biomass fast pyrolysis in an entrained flow reactor [1], yet it could constitute an alternative to the better-known fluidised bed pyrolysis process. In the context of the BOIL project with the CCIAG Company (Grenoble district heating), a new pilot based on an entrained flow reactor concept has been designed [2]. The pilot design has been carried out on the basis of woody biomass fast pyrolysis experiments and modeling performed in a drop tube reactor as a first step laboratory-scale study, and also CFD modeling [2-3]. The facility is composed of a biomass injection system with a hopper and a feeding screw, an electrically heated pyrolysis reactor, a cyclone to separate gas and char, 3 heat exchangers to cool the gas (at 30°C, 0°C and 0°C respectively) and condense bio-oil, and a post-combustion unit to burn the incondensable species. Gas temperature is maintained at 350°C from the reactor outlet to the entrance of the first heat exchanger in order to avoid bio-oil condensation. Several conditions were tested in 14 runs: 3 different biomass feedstocks, varying biomass feeding rates from 2 to 9 kg/h and two reactor temperatures 500°C and 550°C. 85 kg of bio-oil has been produced for combustion tests. Recovered bio-oil mass yield is on average 50%, its LHV is about 15 MJ/kg, its water content 26%w and its pH 2.15. We identified three main difficulties during the runs: about 15% of the bio-oil go through the heat exchanger, some char particles go through the cyclone which causes regular plugging of the first heat exchanger. Detailed analyses of the bio-oil produced have been done and the chemical and physical bio-oil characteristics have been compared to the European Standard recommendations [4]. With a regularly cleaning of the first heat exchanger, we successfully produce bio-oil with physical and chemical properties in agreement with the European Standard recommendations. Combustion tests of the bio-oil produced have been carried on by the CIRAD. They succeeded in obtaining a stable flame (without the use of a pilot flame) in a 50 kW burner and a 250 kW combustion chamber. However the physical and chemical characteristics of the bio-oil involve the use of specific pump and pulverization system adapted. In perspective for future projects, it would be interesting to perform pilot modifications in order to increase bio-oil yield and to minimize heat exchanger cleaning, and to test other resources like agricultural biomass or solid recovered fuels. Bibliography 1. J.A. Knight, C.W. Gorton, R.J. Kovac, Biomass 6, pp. 69-76, 1984. 2. Fast pyrolysis reactor for organic biomass materials with against flow injection of hot gases - US 20170166818 A1 3. Guizani, S.Valin, J.Billlaud, M.Peyrot, S.Salvador, Fuel, 2017, 207, pp.71-84. 4. C.Guizani, S.Valin, M.Peyrot, G.Ratel S.Salvador, Woody biomass fast pyrolysis in a drop tube reactor - Pyro2016 conference 5. Fast pyrolysis bio-oils for industrial boilers – Requirements and test methods – EN 1690