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In this paper, we report on laser patterned vacuum processed organic solar cells using an infrared ultra short pulse laser. Laser patterning is performed on all layers, electrodes as well as organic layers, to produce fast, reproducible, and precise scribes. The structuring enables monolithically interconnecting several cells to mini-modules. For patterning the silver top electrode, a plasma process is introduced which lowers the ablation threshold and minimizes protrusion-induced shunt formation. Finally, we demonstrate the up-scaling of organic mini-modules to an area of 64 cm2 with a geometric fill factor of 94% and a power conversion efficiency on the aperture area of 4.3%.

To establish whether fishy off-flavour observed in cows' milk in Sweden is due to abnormal concentrations of trimethylamine (TMA) in milk, 15 milk samples from 13 cows of the Swedish Red and White breed (SRB) were analysed for this compound using dynamic headspace (DHS) gas chromatography (GC). A mass selective detector (MSD) was used for the qualitative and a flame ionization detector (FID) for the quantitative analyses. Further confirmation was obtained using a solid phase microextraction (SPME) followed by GC-olfactometry (GC-O) and GC-NPD (nitrogen and phosphorus detector). Samples were also evaluated by a two-person organoleptic panel for the presence of fishy off-flavour. Results showed that the seven milk samples with a fish-like taint contained >1 mg TMA/kg milk, whereas, with a single exception, the seven samples that were judged to be normal did not contain this compound. Furthermore, there were indications of a dose-dependent relationship between TMA concentration and fishy off-flavour score.

This preliminary study aims to compare two different extraction and concentration methods often used for the gas chromatographic analysis of volatile components in food to determine the advantages and drawbacks of both for future routine investigation of PDO (protected designation origin) ewes’ milk cheeses. Roncal, Pecorino Sardo and Fiore Sardo were investigated at different ripening stages. The dynamic headspace technique using a Purge & Trap device (DHS) makes it possible to extract more highly volatile compounds than the simultaneous distillation extraction (SDE) method. Consequently, the latter is more efficient for extracting low-volatile components such as phenols, free fatty acids, lactones and longer-chain aldehydes, ketones, alcohols and esters. These two extraction methods are therefore complementary.

This paper examines the distribution of mono- and sesquiterpene secondary metabolites in 47 plants present in grazing areas from which cheeses are produced. In total, 54 terpenoid volatiles, derived from both highland and lowland plants, were obtained by a gaseous purge-and-trap system without the use of organic solvents and then identified by automated GC/MSD-FID analysis using mass spectral libraries, retention indices, and data acquired by the authors with authentic substances. Single ion monitoring proved valuable in identifying overlapping compounds with similar spectra for the subsequent semiquantitative determination of compositions. These are displayed as radar plots. It is suggested that flavor/aroma differences in cheeses produced from animals grazing in different areas and seasons arise from species (n = 38), phenological stages (n = 8), locations (n = 4), and seasonal variation in terpenoids present (the most common were trans-β-ocimene, limonene, and trans-β-caryophyllene). This hypothesis is...

The photovoltaic (PV) industry requires higher efficiencies at lower manufacturing costs to become competitive with other power generation techniques. There are several approaches to increase the efficiency of solar cells. For example enhancements of the way photons are absorbed and how they generate charge carriers with low losses. Today, the so called first generation of photovoltaic devices based on crystalline silicon wafers are produced on a multi-GW-level. However, in most production lines there is only one laser process used to electrically isolate front and rear side of the cell. Lasers are predestined to generate local structures which will be required to manufacture high efficient solar cells. As an example we will show results on the interaction of ultra short laser pulses with dielectric films on silicon. Second generation photovoltaic modules are based on thin films. These modules are monolithically interconnected by laser scribing of the films. Tools for amorphous silicon are well established, while there are a lot of challenges to scribe CIGS layers. Within this paper we will show new results on the temporal evolution of a laser induced "lift-off" process to scribe the molybdenum back electrode.

The details of the melt flow dynamics in deep-penetration welding as well as in laser cutting are still not completely understood. In addition, control of the melt flow might help to suppress or eliminate defects such as spattering, humping or dross formation.The present paper describes the use of a short-pulse laser to influence the behavior of the melt flow. First results show that the melt pool dynamics can be influenced very significantly with less than 1% of additional average power of pulsed laser radiation.A 4’000 W lamp-pumped cw solid-state laser focused to a spot diameter of 450 µ m was used as heating source to generate a keyhole and the melt pool. A diode-pumped Q-switched (QS-) laser delivering 20 ns, 4 mJ pulses at 4 kHz was used to influence the melt pool. The two lasers were overlapped in the interaction region by angular multiplexing. The position of the QS-laser could be adjusted arbitrarily with respect to the cw-laser. The experiments were made on sheets of stainless steel and aluminum and analyzed by means of a high-speed camera.Completely different effects were observed depending on the position of the QS-laser with respect to the keyhole proving that the melt pool dynamics can significantly be influenced with the additional short laser pulses. These preliminary results allow for estimations on the physical quantities such as short pulse absorption, energy transfer and melt flow speed.The details of the melt flow dynamics in deep-penetration welding as well as in laser cutting are still not completely understood. In addition, control of the melt flow might help to suppress or eliminate defects such as spattering, humping or dross formation.The present paper describes the use of a short-pulse laser to influence the behavior of the melt flow. First results show that the melt pool dynamics can be influenced very significantly with less than 1% of additional average power of pulsed laser radiation.A 4’000 W lamp-pumped cw solid-state laser focused to a spot diameter of 450 µ m was used as heating source to generate a keyhole and the melt pool. A diode-pumped Q-switched (QS-) laser delivering 20 ns, 4 mJ pulses at 4 kHz was used to influence the melt pool. The two lasers were overlapped in the interaction region by angular multiplexing. The position of the QS-laser could be adjusted arbitrarily with respect to the cw-laser. The experiments were made on sheets of stainless steel and aluminum...

Ablation and drilling utilising short pulsed solid state lasers are becoming increasingly important technologies for micro-machining, micro-structuring and micro-drilling. Ablative drilling using pulses shorter than 10 ps results in a high-precision processes and outstanding quality due to negligible heating of the workpiece and consequently a reduced formation of recast. The advantages of ultra-short pulsed lasers have thus proved to be attractive for industrial applications. Corresponding to this development, process monitoring and control turn out to be an essential requirement. Different aspects of the drilling process such as borehole depth, moment of break through and end of the process have to be monitored.In this paper we present a method that permits the determination of borehole depth as well as the detection of completion of desired channel morphology. The method utilizes the detection of shock waves generated during the interaction between laser beam and irradiated material. The results prove that the proposed method offers a potential for on-site diagnostics of the laser drilling process.Ablation and drilling utilising short pulsed solid state lasers are becoming increasingly important technologies for micro-machining, micro-structuring and micro-drilling. Ablative drilling using pulses shorter than 10 ps results in a high-precision processes and outstanding quality due to negligible heating of the workpiece and consequently a reduced formation of recast. The advantages of ultra-short pulsed lasers have thus proved to be attractive for industrial applications. Corresponding to this development, process monitoring and control turn out to be an essential requirement. Different aspects of the drilling process such as borehole depth, moment of break through and end of the process have to be monitored.In this paper we present a method that permits the determination of borehole depth as well as the detection of completion of desired channel morphology. The method utilizes the detection of shock waves generated during the interaction between laser beam and irradiated material. The results prove ...

The aim of this study was to characterise the volatile flavour compounds in a Gruyere-type cheese manufactured from pasteurised milk using different strains of Lactobacillus casei. These strains were used as non-starter cultures to manufacture the different cheeses. A dynamic headspace extraction technique, purge and trap, coupled to gas chromatography-mass spectrometry (GC-MS), and solvent assisted flavour evaporation (SAFE) in combination with GC-MS and GC-olfactometry (GCO) were used to determine the volatile aroma compounds formed after 180 days of ripening. The purge and trap method revealed aldehydes and ketones, such as 2-methylpropanal, 2-methylbutanal, 3-methylbutanal, and 2,3-butanedione, as well as dimethyl disulfide and dimethyl trisulfide among other compounds, which have been described earlier as key aroma compounds of Gruyere and Cheddar cheeses. Free fatty acids were not detected by the purge and trap extraction method. On the other hand, the analysis of the SAFE extract revealed intense signals for propanoic, butanoic, 2- and 3-methylbutanoic acid as well as pentanoic acid and hexanoic acid. Less volatile, more polar odorants, such as the caramel-like 2,5-dimethyl-4-hydroxy-3(2H)-furanone and 2-ethyl-4-hydroxy-5-methyl-3(2H)-furanone, but also the mushroom-like smelling 1-octen-3-one were detected in the SAFE extract by GCO, however, not using purge and trap GC-MS.

After oral administration of piperazine citrate to hens, this antihelmintic agent appeared unchanged in the eggs. After a therapeutic dose of ca. 0.9 g piperazine citrate per hen, a maximum level of 1.5 mg piperazine/kg egg was found two days after the application. The elimination half-life was 29 h and piperazine was found in the eggs up to 17 days after administration (limit of detection: 1 microgram/kg). Piperazine determination was performed by HPLC of the dansylderivative after clean-up by TLC.

A method for the determination of glyphosate and its major metabolite aminomethylphosphonic acid (AMPA) is described. With a detection limit of 0.02 microgram/l, the method suitably fulfills the requirements of the Swiss legislation (tolerance value of 0.1 micrograms/l water). The compounds are derivatized directly in the original water sample with 9-fluorenylmethyl chloroformate (FMOCC1) in order to obtain extractable and fluorescent derivatives. These are extracted with organic solvents and determined by HPLC using a fluorescence detector. Neither of the compounds could be detected in 151 tap water samples from the Canton of Berne.

The transition of Morantel into bovine milk was studied with three lactating cows. The active compound was administered as Paratect Bolus which continuously releases the anthelmintic agent. No residues of Morantel could be detected throughout the 92-day experiment (limit of detection: 0.5 μg Morantel tartrate/kg milk), nor could the compound be found in the blood serum at day 35 of the experiment. The same day an amount of 825 μg/kg was observed in faeces.