Plasma-Enhanced Laser Materials Processing

In the last few years, the combination of laser irradiation with atmospheric pressure plasmas, also referred to as laser–plasma hybrid technology, turned out to be a powerful technique for different materials processing tasks. This chapter gives an overview on this novel approach. Two methods, simultaneous and sequential laser-plasma processing, are covered. In the first case, both the plasma and the laser irradiation are applied to the substrate at the same time. Depending on the process gas and the discharge type, the plasma provides a number of species that can contribute to the laser process plasma-physically or plasma-chemically. Sequential plasma-enhanced laser processing is based on a plasma-induced modification of essential material properties, thus improving the coupling of laser energy into the material during subsequent laser ablation. Simultaneous plasma-assisted laser processing allows increasing the efficiency of a number of different laser applications such as cleaning, microstructuring, or annealing processes. Sequential plasma-assisted laser processing is a powerful method for the processing of transparent media due to a reduction in the laser ablation threshold and an increase in the ablation rate at the same time. In this chapter, the possibilities, underlying mechanisms, performance, and limits of the introduced approaches are presented in detail

The description of F2F_2 at low Q2Q^2

We analyse the data for the proton structure function $F_2$ over the entire $Q^2$ domain, including especially low $Q^2$, in terms of perturbative and non-perturbative QCD contributions. The small distance configurations are given by perturbative QCD, while the large distance contributions are given by the vector dominance model and, for the higher mass $q \bar{q}$ states, by the additive quark approach. The interference between states of different $q\bar{q}$ mass (in the perturbative contribution) is found to play a crucial role in obtaining an excellent description of the data throughout the whole $Q^2$ region, including photoproduction.Comment: 18 pages, Latex, 10 ps figures; references to the photoproduction data points have been change

Spatial organisation and population size of small Cucuteni-Tripolye settlements: Results of geomagnetic surveys in Baia and Adâncata, Suceava County, Bucovina, Eastern Romania

Geomagnetic research and drillings provide new results regarding settlement organisation and population size of three small settlements from the Pre-Cucuteni and the Cucuteni A-B period of Suceava County in Romanian Bucovina. In these settlements from different stages of the Cucuteni-Tripolye complex, domestic dwellings can be distinguished from clearly oversized (special?) buildings, which are situated in central locations and sometimes contain special inventories. Different principles of settlement organisation are visible, which each show far-reaching references to the Central Balkans, on the one hand, and the Bug-Dnieper interfluve on the other hand. Based on analogies with other Cucuteni-Tripolye sites, consistent populations with less than 200 inhabitants are reconstructed

Light emission from dye-doped cholesteric liquid crystals at oblique angles: simulation and experiment

Dye-doped cholesteric liquid crystals with a helical pitch of the order of a wavelength have a strong effect on the fluorescence properties of dye molecules. This is a promising system for realizing tunable lasers at low cost. We apply a plane wave model to simulate the spontaneous emission from a layer of cholesteric liquid crystal.We simulate the spectral and angle dependence and the polarization of the emitted light as a function of the order parameter of the dye in the liquid crystal.Measurements of the angle dependent emission spectra and polarization are in good agreement with the simulations

Co-determination in Germany : the impact on the market value of the firm

Paper presented at the conference on "Employees and Corporate Governance", Columbia University Law School, New York, November 22, 199

Implant survival after surgical treatment of peri‐implantitis lesions by means of deproteinized bovine bone mineral with 10% collagen: 10‐year results from a prospective study

ObjectivesTo evaluate the 10‐year outcomes of a regenerative surgical treatment of single peri‐implantitis intrabony defects, by means of deproteinized bovine bone mineral with 10% collagen (DBBMC).Material and MethodsThe original population consisted of 26 patients with one crater‐like defect, around either SLA or TPS dental implants, with a probing depth ≥6 mm and no implant mobility. After debridement and surface decontamination, the defects were filled with DBBMC. Subsequently, patients were placed in an individualized supportive peri‐implant/periodontal therapy (SPT) program.ResultsFourteen patients (eight SLA and six TPS) reached the 10‐year examination. The overall implant survival rate was 67%, 80% for the SLA, and 55% for the TPS implants. During SPT, five patients were lost to follow‐up, eight patients needed additional antibiotic and/or surgical therapy, and seven patients had the implant removed. PD was reduced from 6.6 ± 1.3 to 3.2 ± 0.7 mm in SLA and from 7.2 ± 1.5 to 3.4 ± 0.6 mm in TPS. BOP decreased from 75.0 ± 31.2% to 7.5 ± 12.1% (SLA) and from 90.0 ± 12.9% to 30.0 ± 19.7% (TPS). Treatment success was found in 5 of the 12 SLA (42%) and in 4 of the 14 TPS (29%).ConclusionsThe proposed reconstructive treatment, followed by SPT, was able to maintain in function the majority of SLA implants, although the overall treatment success was limited and many of TPS implants were removed. Therefore, the decision to treat implants affected by peri‐implantitis should be based on several factors, including surface characteristics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156127/3/clr13628-sup-0001-Supinfo.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156127/2/clr13628_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156127/1/clr13628.pd

Observation of hard scattering in photoproduction events with a large rapidity gap at HERA

Events with a large rapidity gap and total transverse energy greater than 5 GeV have been observed in quasi-real photoproduction at HERA with the ZEUS detector. The distribution of these events as a function of the $\gamma p$ centre of mass energy is consistent with diffractive scattering. For total transverse energies above 12 GeV, the hadronic final states show predominantly a two-jet structure with each jet having a transverse energy greater than 4 GeV. For the two-jet events, little energy flow is found outside the jets. This observation is consistent with the hard scattering of a quasi-real photon with a colourless object in the proton.Comment: 19 pages, latex, 4 figures appended as uuencoded fil

Transformando camponeses de subsistência em servos de ecossistemas: desigualdade e a produção de recursos naturais na República Democrática Popular do Laos

This paper examines the nexus of nature conservation, productivity and domination in inclusive conservation approaches. It argues that the turning of subsistence peasants into “stewards and custodians of biodiversity” (CBD) represents a soft form of domination according to the false alternatives of ecological instrumentality in that local development is subordinated to supposed “natural” constraints. The argument draws from critical theories of societal nature relations (Horkheimer & Adorno, 2002; Görg. 2003; Moore, 2015) as well as from extensive research on ecotourism as an instrument to reconcile conservation and development in the Lao People’s Democratic Republic. From this angle, conservation is seen as a way to produce “natural” resources building on, perpetuating and creating various social inequities, based on the fiction that “nature” is essentially non-human. This case is made with regard to National Protected Areas in Laos, which are designed explicitly to accommodate local people’s needs. Among other things, ecotourism is employed to create a source of income alternative to practices seen as “unsustainable”. Thereby, economic and also moral stakes in untouched resources are to be implanted. In such way, a compromise between (rather than a reconciliation of) conservation and development is imposed which is largely alien to the lived realities of local people, and only accounting partly for their needs and aspirations  – an imposition which tends to produce its own countercurrents, again tying into productivity and inequality. This paper thus analyzes the workings of the nature/society dualism underlying ecological instrumentality as experienced in ecotourism as a tool for nature conservation in Laos.Este artigo examina o nexo entre conservação da natureza, produtividade e dominação nas abordagens de conservação inclusivas. Argumenta que a transformação de camponeses de subsistência em “administradores e custodiantes de biodiversidade” (CBD) representa uma forma suave de dominação de acordo com as falsas alternativas de instrumentalidade ecológica em que o desenvolvimento local é subordinado a supostas limitações “naturais”. O argumento se baseia em teorias críticas das relações entre natureza e sociedade (Horkheimer & Adorno, 2002; Görg, 2003; Moore, 2015), bem como em uma extensa pesquisa sobre o ecoturismo como um instrumento para conciliar conservação e desenvolvimento na República Democrática Popular do Laos. Sob esse ângulo, a conservação é vista como uma forma de produzir recursos “naturais”, perpetuando e criando várias desigualdades sociais, com base na ficção de que a “natureza” é essencialmente não humana. Este caso é defendido no que diz respeito às Áreas Nacionais Protegidas no Laos, que são projetadas explicitamente para acomodar as necessidades da população local. Entre outras coisas, o ecoturismo é empregado para criar uma fonte alternativa de renda a práticas vistas como “insustentáveis”. Assim, espera-se implantar interesses econômicos e também morais sobre recursos intocados. Desta forma, um compromisso (em vez de uma reconciliação) entre conservação e desenvolvimento é imposto, em grande parte alheio às realidades vividas pela população local, e só respondendo parcialmente às suas necessidades e aspirações – uma imposição que tende a produzir suas próprias contracorrentes, mais uma vez atando produtividade e desigualdade. Este artigo analisa, assim, o funcionamento do dualismo natureza/sociedade, enfatizando a instrumentalidade ecológica experimentada no ecoturismo como ferramenta para a conservação da natureza no Laos