Differential Scattering Cross-Sections for the Different Product Vibrational States in the Ion-Molecule Reaction Ar+ + N2

The charge transfer reaction Ar+ + N2 --> Ar + N2+ has been investigated in a crossed beam experiment in combination with three-dimensional velocity map imaging. Angular differential state-to-state cross sections were determined as a function of the collision energy. We found that scattering into the first excited vibrational level dominates as expected, but only for scattering in the forward direction. Higher vibrational excitations up to v'=6 have been observed for larger scattering angles. For decreasing collision energy, scattering into higher scattering angles becomes increasingly important for all kinematically allowed quantum states. Our detailed measurements indicate that a quantitative agreement between experiment and theory for this basic ion-molecule reaction now comes within reach.Comment: accepted to Phys. Rev. Let

Utilizing artificial intelligence and machine learning for monitoring and modeling road conditions

Abstract. Road maintenance requires resources increasingly as climate change and high traffc volume in populous areas infict a signifcant strain on the traffc infrastructure. In rural areas, the car is usually the only mode of transport and long driving distances with high average speeds are covered on a daily basis. The majority of maintenance resources are located in densely populated cities, making the maintenance of rural roads challenging and expensive. New scalable methods to optimize the usage of road maintenance resources are demanded. This thesis reviews several artifcial intelligence and machine learning based techniques and systems designed for monitoring, evaluating, and predicting road condition and deterioration. In the implementation part of the thesis, two classifcation models, based on logistic regression and support vector machines, are trained to classify fve different types of normal or damaged road segments from vertical acceleration data measured with smartphone sensors. A classifcation accuracy of 70.9% was achieved with logistic regression and 73.9% with support vector machine. The results of the implementation provide more evidence that vibration-based road condition monitoring systems can identify road anomalies with good accuracy and could have practical utility in road maintenance related tasks.Tekoälyn ja koneoppimisen hyödyntäminen tien kunnon tunnistamisessa ja mallintamisessa. Tiivistelmä. Teiden huoltotoimenpiteet vaativat resursseja enenevissä määrin, sillä ilmastonmuutos ja vilkastuva liikenne tiheästi asutuilla alueilla kuormittavat liikenneinfrastruktuuria merkittävästi. Harvaan asutuilla alueilla auto on usein ainoa kulkuväline, ja asukkaat keskimäärin ajavat pidempiä matkoja suuremmalla keskinopeudella. Suurin osa teiden huoltoon vaadittavista resursseista keskittyy tiheään asutuille taajama-alueille, tehden harvaan asuttujen alueiden tiestön huollosta haastavaa. Uusia skaalautuvia menetelmiä teiden huoltoon vaadittavien resurssien optimoimiseksi tarvitaan. Tässä tutkielmassa tarkastellaan erilaisia tekoälyyn ja koneoppimiseen pohjautuvia menetelmiä ja järjestelmiä teiden kunnon tarkastamista, arviointia ja mallintamista varten. Tutkielman suoritusosassa kaksi luokittelumallia, jotka pohjautuvat logistiseen regressioon ja tukivektorikoneeseen, koulutetaan erottamaan viisi erityyppistä normaalia tai vaurioitunutta tieosuutta älypuhelimen liikesensoreilla kerätyistä vertikaalisista kiihtyvyysanturimittauksista. Logistinen regressiomalli luokitteli testidataa keskimäärin 70.9% tarkkuudella, kun taas tukivektorikoneeseen perustuva malli saavutti vastaavasti 73.9% luokittelutarkkuuden. Suoritusosan tulokset antavat näyttöä siitä, että värähtelymittauksiin perustuvat tien kunnon tunnistamiseen suunnitellut järjestelmät voivat tunnistaa erinäisiä poikkeamia tien pinnassa hyvällä tarkkuudella, ja että näistä järjestelmistä voisi olla hyötyä teiden huoltoon liittyvissä toimenpiteissä

Pulse shape discrimination performance of Inverted Coaxial Ge detectors

We report on the characterization of two inverted coaxial Ge detectors in the context of being employed in future $^{76}$Ge neutrinoless double beta ($0\nu\beta\beta$) decay experiments. It is an advantage that such detectors can be produced with bigger Ge mass as compared to the planar Broad Energy Ge detectors (BEGe) that are currently used in the GERDA $0\nu\beta\beta$ decay experiment. This will result in lower background for the search of $0\nu\beta\beta$ decay due to a reduction of cables, electronics and holders. The measured resolution near the $^{76}$Ge Q-value at 2039 keV is 2.5 keV and their pulse-shape characteristics are similar to BEGe-detectors. It is concluded that this type of Ge-detector is suitable for usage in $^{76}$Ge $0\nu\beta\beta$ decay experiments

Comparing CλaSH and VHDL by implementing a dataflow processor

As embedded systems are becoming increasingly complex, the design process and verification have become very time-consuming. Additionally, specifying hardware manually in a low-level hardware description language like VHDL is usually an error-prone task. In our group, a tool (the ClaSH compiler) was developed to generate fully synthesisable VHDL code from a specification given in the functional programming language Haskell. In this paper, we present a comparison between two implementations of the same design by using ClaSH and hand-written VHDL. The design is a simple dataflow processor. As measures of interest area, performance, power consumption and source lines of code (SLOC) are used. The obtained results indicate that the ClaSH -generated VHDL code as well as the netlist after synthesis and place and route are functionally correct. The placed and routed hand-written VHDL code has also the correct behaviour. Furthermore, a similar performance is achieved. The power consumption is even lower for the ClaSH implementation. The SLOC for ClaSH is considerably smaller and it is possible to specify the design in a much higher level of abstraction compared to VHDL

Modelling the role of electron attachment rates on column density ratios for CnH-/CnH (n=4; 6; 8) in dense molecular clouds

(abridged) The fairly recent detection of a variety of anions in the Interstellar Molecular Clouds have underlined the importance of realistically modeling the processes governing their abundance. To this aim, our earlier calculations for the radiative electron attachment (REA) rates for C4H-, C6H-, and C8H- are employed to generate the corresponding column density ratios of anion/neutral (A/N) relative abundances. The latter are then compared with those obtained from observational measurements. The calculations involved the time-dependent solutions of a large network of chemical processes over an extended time interval and included a series of runs in which the values of REA rates were repeatedly scaled. Macroscopic parameters for the clouds' modeling were also varied to cover a broad range of physical environments. It was found that, within the range and quality of the processes included in the present network,and selected from state-of-the-art astrophysical databases, the REA values required to match the observed A/N ratios needed to be reduced by orders of magnitude for C4H- case, while the same rates for C6H- and C8H- only needed to be scaled by much smaller factors. The results suggest that the generally proposed formation of interstellar anions by REA mechanism is overestimated by current models for the C4H- case, for which is likely to be an inefficient path to formation. This path is thus providing a rather marginal contribution to the observed abundances of C4H-, the latter being more likely to originate from other chemical processes in the network, as we discuss in some detail in the present work.Possible physical reasons for the much smaller differences against observations found instead for the values of the (A/N) ratios in two other, longer members of the series are put forward and analyzed within the evolutionary modeling discussed in the present work.Comment: Journal of Physics B, accepte

Formation of ultracold LiCs molecules

We present the first observation of ultracold LiCs molecules. The molecules are formed in a two-species magneto-optical trap and detected by two-photon ionization and time-of-flight mass spectrometry. The production rate coefficient is found to be in the range 10^{-18}\unit{cm^3s^{-1}} to 10^{-16}\unit{cm^3s^{-1}}, at least an order of magnitude smaller than for other heteronuclear diatomic molecules directly formed in a magneto-optical trap.Comment: 8 pages, 2 figure