Methods to assess the stability of a bicycle rider system

The SOFIE (Intelligent Assisted Bicycles) project wishes to create performance and design guidelines for mechatronic appliances which improve the stability of electric bicycles, so-called intelligent stability assist devices (IAD). To achieve this goal, a stability hypothesis, an advanced rider/bicycle model and bicycle stability test bench, will be created. This paper describes the development of these components and its goal is to present the project design. The stability hypothesis is based on the concept that the Centre of Mass (CoM) of the bicycle/rider system stays within certain lateral margins from the heading of a bicycle. The rider/bicycle model is created in Adams for multi-body dynamic simulations. The bicycle stability test bench is designed to be interchangeable between bicycles. The model, the test bench and the stability hypothesis will be used to validate the effectiveness of the IAD’s and assist in their design

Physical Characteristics of a Dark Cloud in an Early Stage of Star Formation toward NGC 7538: an Outer Galaxy Infrared Dark Cloud?

In the inner parts of the Galaxy the Infrared Dark Clouds (IRDCs) are presently believed to be the progenitors of massive stars and star clusters. Many of them are predominantly devoid of active star formation and for now they represent the earliest observed stages of massive star formation. Their Outer Galaxy counterparts, if present, are not easily identified because of a low or absent mid-IR background. We characterize the ambient conditions in the Outer Galaxy IRDC candidate G111.80+0.58, a relatively quiescent molecular core complex in the vicinity of NGC7538. We conduct molecular line observations on a number of dense cores and analyze the data in terms of excitation temperature, column and volume density, mass and stability. The temperatures (15-20K) are higher than expected from only cosmic ray heating, but comparable to those found in massive cores. Star forming activity could be present in some cores, as indicated by the presence of warm gas and YSO candidates. The observed super-thermal line-widths are typical for star forming regions. The velocity dispersion is consistent with a turbulent energy cascade over the observed size scales. We do not find a correlation between the gas temperature and the line-width. The LTE masses we find are much larger than the thermal Jeans mass and fragmentation is expected. In that case the observed lines represent the combined emission of multiple unresolved components. We conclude that G111.80+0.58 is a molecular core complex with bulk properties very similar to IRDCs in an early, but not pristine, star forming state. The individual cores are close to virial equilibrium and some contain sufficient material to form massive stars and star clusters. The ambient conditions suggest that turbulence is involved in supporting the cores against gravitational collapse.Comment: Accepted for publication in A&A -- 19 pages, 9 figures -- high resolution available at http://www.astro.rug.nl/~frieswyk/Data/Research/OGIRDC/index.htm

A new species of Colostethus (Anura, Dendrobatidae) from French Guiana with a redescription of Colostethus beebei (Noble, 1923) from its type locality

A new species of Colostethus, long mistaken for Colostethus beebei, is described from French Guiana. The new species can be distinguished from congeners by absence of median lingual process, first finger longer than second, third finger not distinctly swollen in males, differences in tadpole morphology, coloration and pattern (e.g. absence of dorsolateral stripe), bioacoustics, and reproductive behavior. A complete redescription of Colostethus beebei plus description of its tadpole and call is provided on the basis of recently collected topotypic specimens. The range of C. beebei is restricted to the Kaieteur plateau, Pakaraima Mountains, Guyana

Water and ammonia abundances in S140 with the Odin satellite

We have used the Odin satellite to obtain strip maps of the ground-state rotational transitions of ortho-water and ortho-ammonia, as well as CO(5-4) and 13CO(5-4) across the PDR, and H218O in the central position. A physi-chemical inhomogeneous PDR model was used to compute the temperature and abundance distributions for water, ammonia and CO. A multi-zone escape probability method then calculated the level populations and intensity distributions. These results are compared to a homogeneous model computed with an enhanced version of the RADEX code. H2O, NH3 and 13CO show emission from an extended PDR with a narrow line width of ~3 kms. Like CO, the water line profile is dominated by outflow emission, however, mainly in the red wing. The PDR model suggests that the water emission mainly arises from the surfaces of optically thick, high density clumps with n(H2)>10^6 cm^-3 and a clump water abundance, with respect to H2, of 5x10^-8. The mean water abundance in the PDR is 5x10^-9, and between ~2x10^-8 -- 2x10^-7 in the outflow derived from a simple two-level approximation. Ammonia is also observed in the extended clumpy PDR, likely from the same high density and warm clumps as water. The average ammonia abundance is about the same as for water: 4x10^-9 and 8x10^-9 given by the PDR model and RADEX, respectively. The similarity of water and ammonia PDR emission is also seen in the almost identical line profiles observed close to the bright rim. Around the central position, ammonia also shows some outflow emission although weaker than water in the red wing. Predictions of the H2O(110-101) and (111-000) antenna temperatures across the PDR are estimated with our PDR model for the forthcoming observations with the Herschel Space Observatory.Comment: 13 pages, 14 figures, 10 tables. Accepted for publication in Astronomy & Astrophysics 14 November 200

Modeling water emission from low-mass protostellar envelopes

Within low-mass star formation, water vapor plays a key role in the chemistry and energy balance of the circumstellar material. The Herschel Space Observatory will open up the possibility to observe water lines originating from a wide range of excitation energies.Our aim is to simulate the emission of rotational water lines from envelopes characteristic of embedded low-mass protostars. A large number of parameters that influence the water line emission are explored: luminosity, density,density slope and water abundances.Both dust and water emission are modelled using full radiative transfer in spherical symmetry. The temperature profile is calculated for a given density profile. The H2O level populations and emission profiles are in turn computed with a non-LTE line code. The results are analyzed to determine the diagnostic value of different lines, and are compared with existing observations. Lines can be categorized in: (i) optically thick lines, including ground-state lines, mostly sensitive to the cold outer part; (ii) highly excited (E_u>200-250 K) optically thin lines sensitive to the abundance in the hot inner part; and (iii) lines which vary from optically thick to thin depending on the abundances. Dust influences the emission of water significantly by becoming optically thick at the higher frequencies, and by pumping optically thin lines. A good physical model of a source, including a correct treatment of dust, is a prerequisite to infer the water abundance structure and possible jumps at the evaporation temperature from observations. The inner warm (T>100 K) envelope can be probed byhighly-excited lines, while a combination of excited and spectrally resolved ground state lines probes the outer envelope. Observations of H218O lines, although weak, provide even stronger constraints on abundances.Comment: 17 pages with an online appendix of 6 pages. Accepted by A&A. Several figures are too large for astro-ph. These can be downloaded from http://www.strw.leidenuniv.nl/~kempen/water.ph

Smartphone Apps for Measuring Human Health and Climate Change Co-Benefits: A Comparison and Quality Rating of Available Apps.

BACKGROUND: Climate change and the burden of noncommunicable diseases are major global challenges. Opportunities exist to investigate health and climate change co-benefits through a shift from motorized to active transport (walking and cycling) and a shift in dietary patterns away from a globalized diet to reduced consumption of meat and energy dense foods. Given the ubiquitous use and proliferation of smartphone apps, an opportunity exists to use this technology to capture individual travel and dietary behavior and the associated impact on the environment and health. OBJECTIVE: The objective of the study is to identify, describe the features, and rate the quality of existing smartphone apps which capture personal travel and dietary behavior and simultaneously estimate the carbon cost and potential health consequences of these actions. METHODS: The Google Play and Apple App Stores were searched between October 19 and November 6, 2015, and a secondary Google search using the apps filter was conducted between August 8 and September 18, 2016. Eligible apps were required to estimate the carbon cost of personal behaviors with the potential to include features to maximize health outcomes. The quality of included apps was assessed by 2 researchers using the Mobile Application Rating Scale (MARS). RESULTS: Out of 7213 results, 40 apps were identified and rated. Multiple travel-related apps were identified, however no apps solely focused on the carbon impact or health consequences of dietary behavior. None of the rated apps provided sufficient information on the health consequences of travel and dietary behavior. Some apps included features to maximize participant engagement and encourage behavior change towards reduced greenhouse gas emissions. Most apps were rated as acceptable quality as determined by the MARS; 1 was of poor quality and 10 apps were of good quality. Interrater reliability of the 2 evaluators was excellent (ICC=0.94, 95% CI 0.87-0.97). CONCLUSIONS: Existing apps capturing travel and dietary behavior and the associated health and environmental impact are of mixed quality. Most apps do not include all desirable features or provide sufficient health information. Further research is needed to determine the potential of smartphone apps to evoke behavior change resulting in climate change and health co-benefits

Water abundances in high-mass protostellar envelopes: Herschel observations with HIFI

We derive the dense core structure and the water abundance in four massive star-forming regions which may help understand the earliest stages of massive star formation. We present Herschel-HIFI observations of the para-H2O 1_11-0_00 and 2_02-1_11 and the para-H2-18O 1_11-0_00 transitions. The envelope contribution to the line profiles is separated from contributions by outflows and foreground clouds. The envelope contribution is modelled using Monte-Carlo radiative transfer codes for dust and molecular lines (MC3D and RATRAN), with the water abundance and the turbulent velocity width as free parameters. While the outflows are mostly seen in emission in high-J lines, envelopes are seen in absorption in ground-state lines, which are almost saturated. The derived water abundances range from 5E-10 to 4E-8 in the outer envelopes. We detect cold clouds surrounding the protostar envelope, thanks to the very high quality of the Herschel-HIFI data and the unique ability of water to probe them. Several foreground clouds are also detected along the line of sight. The low H2O abundances in massive dense cores are in accordance with the expectation that high densities and low temperatures lead to freeze-out of water on dust grains. The spread in abundance values is not clearly linked to physical properties of the sources.Comment: 8 pages, 5 figures, accepted for publication the 15/07/2010 by Astronomy&Astrophysics as a letter in the Herschel-HIFI special issu

Shango businessplan: gecontroleerd schelpdierkweeksysteem, van zaad tot aan consumptiemossel; systeemontwerp, protocollen, technisch-economische haalbaarheid

Het natuurlijke aanbod van uitgangsmateriaal voor schelpdierteelt(zaad) vertoont jaarlijks sterke fluctuaties. Er is daarom behoefte aan nieuwe technieken ten behoeve van de zaadvoorziening. Een nieuwe techniek is productie van zaad op land in een hatchery/nursery Het project is gericht op de mossel (Mytilus Edulis) en het ontwikkelen en uittesten van een prototype hatchery/nursery met growout systemen. De technische beschrijving beperkt zich tot op systeemniveau, inclusief het programma van eisen voor de benodigde componenten. Tevens worden de operationele aspecten in protocollen weergegeven. Tenslotte wordt aan het eind een technisch-economische beschouwing gegeven. De kostprijs voor hatcheryzaad is nog vele malen te hoog t.o.v. bodemzaad en mosselzaadinvang

CHAMP+ observations of warm gas in M17 SW

Since the main cooling lines of the gas phase are important tracers of the interstellar medium in Galactic and extragalactic sources, proper and detailed understanding of their emission, and the ambient conditions of the emitting gas, is necessary for a robust interpretation of the observations. With high resolution (7"-9") maps (~3x3 pc^2) of mid-J molecular lines we aim to probe the physical conditions and spatial distribution of the warm (50 to few hundred K) and dense gas (n(H_2)>10^5 cm^-3) across the interface region of M17 SW nebula. We have used the dual color multiple pixel receiver CHAMP+ on APEX telescope to obtain a 5'.3x4'.7 map of the J=6-5 and J=7-6 transitions of 12CO, the 13CO J=6-5 line, and the {^3P_2}-{^3P_1} 370 um fine-structure transition of [C I] in M17 SW. LTE and non-LTE radiative transfer models are used to constrain the ambient conditions. The warm gas extends up to a distance of ~2.2 pc from the M17 SW ridge. The 13CO J=6-5 and [C I] 370 um lines have a narrower spatial extent of about 1.3 pc along a strip line at P.A=63 deg. The structure and distribution of the [C I] {^3P_2}-{^3P_1} 370 um map indicate that its emission arises from the interclump medium with densities of the order of 10^3 cm^-3. The warmest gas is located along the ridge of the cloud, close to the ionization front. An LTE approximation indicates that the excitation temperature of the embedded clumps goes up to ~120 K. The non-LTE model suggests that the kinetic temperature at four selected positions cannot exceed 230 K in clumps of density n(H_2)~5x10^5 cm^-3, and that the warm T_k>100 K and dense (n(H_2)>10^4 cm^-3) gas traced by the mid-J 12CO lines represent just about 2% of the bulk of the molecular gas. The clump volume filling factor ranges between 0.04 and 0.11 at these positions.Comment: Accepted for publication in Astronomy and Astrophysics, 12 pages, 10 figures, 1 tabl