Laser-induced breakdown spectroscopy (LIBS) in combination with a conventional mine prodder is applied for remote detection of explosives and mine housing materials. High power subnanosecond laser pulses (pulse power Ep = 0.6 mJ and pulse duration Δt = 650 ps) at 1064 nm with a typical repetition rate of 10 kHz are generated by using a passively Q-switched Cr4+:Nd3+:YAG microchip-laser as seed-laser for an Yb-fiber amplifier. In the present investigation, the ratios of “late” and “early” LIBS intensities for the cyanide (CN) plasma emission at 388 nm and for the C-emission at 248 nm are used for data analysis. This allows the classification of different explosives and mine casing materials under real time conditions and also similar applications to materials processing.
Developed societies with advanced economic performance are undoubtedly coupled with the availability of electrical energy. Whilst industrialized nations already started to decrease associated carbon emissions in many business sectors, e.g., by substituting combustion engines with battery-powered vehicles, less developed countries still lack broad coverage of reliable electricity supply, particularly in rural regions. Progressive electrification leads to a need for storage capacity and thus to increasing availability of advanced battery systems. To achieve a high degree of sustainability, re-used batteries from the electromobility sector are appropriate, as they do not consume further primary resources and still have sufficient residual capacity for stationary electrical storage applications. In this article, a blueprint for the electrification of a remote region by utilizing second-life lithium ion traction batteries for an integrated energy system in a stand-alone grid is presented and the implementation by the example case of a Tanzanian island in Lake Victoria is demonstrated. First, economic potentials and expected trends in the disposability of second-life lithium ion batteries and their foreseeable costs are outlined. Subsequently, key decision variables are identified to evaluate logistic aspects and the feasibility of the implementation of an off-grid electrical system in remote areas for economically and geographically unfavorable environments. The practical realization is pictured in detail with a focus on technical performance and safety specificities associated with second-life applications. Therefore, a new type of battery management system is introduced, which meets the special requirements of climate compatibility, low maintenance, enhanced cell balancing capability and cell configuration flexibility, and combined with a fiber-optical sensor system, provides reliable status monitoring of the battery. By carrying out on-site measurements, the overall system efficiency is evaluated along with a sustainability analysis. Finally, the socioeconomic and humanitarian impact for the people on the island is debated.
Two single-mode diode lasers and AgGaS2 as a nonlinear medium are applied for difference frequency generation (DFG) in the mid-infrared spectral range between 4.9 and 6.5 µm. Phase matching is achieved by either temperature tuning or angle tuning of the crystal. Experimentally measured sets of input wavelengths λs and λp, the resulting DFG wavelength λi, and corresponding phase-matching temperatures or angles are compared with the calculated values derived by use of different Sellmeier equations and coefficients and temperature-dispersion equations dn/dT. Our results show that only specific combinations of previously published Sellmeier equations, coefficients, and temperature-dispersion equations are suitable for exact calculations of phase-matching parameters. These combinations reproduce our experimentally obtained phase-matching temperatures and angles with an accuracy of better than 5% and are therefore of fundamental interest for the design of a mid-infrared DFG spectrometer with AgGaS2 as a nonlinear medium.