A readout IC for an uncooled microbolometer infrared FPA with on-chip self-heating compensation in 0.35 μm CMOS

This paper describes a readout integrated circuit architecture for an infrared focal plane array intended for infrared network-attached video cameras in surveillance applications. The focal plane array consists of 352 × 288 uncooled thin-film microbolometer detectors with a pitch of 25 μm, enabling ambient temperature operation. The circuit features a low-noise readout path, detector resistance mismatch correction and a non-linear ramped current pulse scheme for the electrical biasing of the detectors in order to relax the dynamic range requirement of amplifiers and the ADC in the readout channel, imposed by detector process variation and self-heating during readout. The design is implemented in a 0.35-μm standard CMOS process and two versions of a smaller 32 × 32-pixel test chip have been fabricated and measured for evaluation. The latest test chip achieves a dynamic range of 97 dB and an input-referred RMS noise voltage of 6.4 μV yielding an estimated NETD value of 26 mK with f/1 optics. At a frame rate of 60 FPS the chip dissipates 170 mW of power from a 3.4 V supply.     

Crystal Phase Control of Luminescing α‐NaGdF4:Eu3+and β‐NaGdF4:Eu3+ Nanocrystals

NaGdF₄:Eu³⁺, NaEuF₄, and NaGdF₄ nanocrystals were synthesized in the high‐boiling coordinating solvent N‐(2‐hydroxyethyl)‐ethylenediamine (HEEDA). Phase pure nanomaterials, crystallizing either in the cubic α‐phase or the hexagonal β‐phase, were obtained by adjusting one reaction parameter only, i.e., the molar ratio between metal and fluoride ions in the synthesis. The hexagonal β‐phase is formed, if this molar ratio is close to stoichiometric, whereas the cubic α‐phase is obtained in the presence of excess metal ions. The optical properties of the Eu³⁺ doped samples are different for the two crystal phases. The results indicate an increased number of oxygen impurities close to Eu³⁺ ions, if excess metal ions are used in the synthesis.     

Swiss Rainfall Mass Curves and their Influence on Extreme Flood Simulation

Extreme flood estimates for dam safety are routinely obtained from hydrologic simulations driven by selected design storms. The temporal structure of such design storms can be obtained from Rainfall Mass Curves (RMCs), which are adimensionalized curves of the cumulative precipitation depth as a function of event duration. This paper assesses for the first time the spatialand temporal variability of observed RMCs for Switzerland, an Alpine region with complex topography. The relevance of the detected RMC variability for extreme flood estimation is illustrated based on an application to a high elevation catchment, the Mattmark dam catchment in the Swiss Alps. The obtained results underline that quantile RCMs represent a simple yet powerful tool to construct design storms for dam safety verification and that regional, seasonal and event-duration effects on RMCs are small enough to justify the use of a unique set of Swiss-wide quantile RMCs. The presented analysis could be refined in the future by explicitly accounting for orographic, convective or frontal precipitation events.     

OFDM with reduced peak-to-average power ratio by multiple signal representation

In this paper two highly effective, flexible and distortionless peak power reduction schemes for orthogonal frequency division multiplexing (ofdm) with low amount of additional complexity and almost vanishing redundancy are presented. The schemes work with arbitrary numbers of subcarriers and signal sets. The first approach generates a set of several alternative multicarrier signals and selects that transmit signal with the lowest peak power value. The second method optimally combines partial transmit sequences to minimize the peak-to-average power ratio (PAR-coefficient). The schemes are analyzed theoretically and their performance is covered by simulations.     

Surface-immobilized peptide aptamers as probe molecules for protein detection

We demonstrate the use of surface-immobilized, oriented peptide aptamers for the detection of specific target proteins from complex biological solutions. These peptide aptamers are target-specific peptides expressed within a protein scaffold engineered from the human protease inhibitor stefin A. The scaffold provides stability to the inserted peptides and increases their binding affinity owing to the resulting three-dimensional constraints. A unique cysteine residue was introduced into the protein scaffold to allow orientation-specific surface immobilization of the peptide aptamer and to ensure exposure of the binding site to the target solution. Using dual-polarization interferometry, we demonstrate a strong relationship between binding affinity and aptamer orientation and determine the affinity constant KD for the interaction between an oriented peptide aptamer ST(cys+)_(pep9) and the target protein CDK2. Further, we demonstrate the high selectivity of the peptide aptamer STM_(pep9) by exposing surface-immobilized ST(cys+)_(pep9) to a complex biological solution containing small concentrations of the target protein CDK2.     

Toxicological characterization of particulate emissions from straw,Miscanthus, and poplar pellet combustion in residential boilers

Wood pellets have been used in domestic heating appliances for three decades. However, because the share of renewable energy for heating will likely rise over the next several years, alternative biomass fuels, such as short-rotation coppice or energy crops, will be utilized. We tested particulate emissions from the combustion of standard softwood pellets and three alternative pellets (poplar, Miscanthus sp., and wheat straw) for their ability to induce inflammatory, cytotoxic, and genotoxic responses in a mouse macrophage cell line. Our results showed clear differences in the chemical composition of the emissions, which was reflected in the toxicological effects. Standard softwood and straw pellet combustion resulted in the lowest PM₁ mass emissions. Miscanthus sp. and poplar combustion emissions were approximately three times higher. Emissions from the herbaceous biomass pellets contained higher amounts of chloride and organic carbon than the emissions from standard softwood pellet combustion. Additionally, the emissions of the poplar pellet combustion contained the highest concentration of metals. The emissions from the biomass alternatives caused significantly higher genotoxicity than the emissions from the standard softwood pellets. Moreover, straw pellet emissions caused higher inflammation than the other samples. Regarding cytotoxicity, the differences between the samples were smaller. Relative toxicity was generally highest for the poplar and Miscanthus sp. samples, as their emission factors were much higher. Thus, in addition to possible technical problems, alternative pellet materials may cause higher emissions and toxicity. The long-term use of alternative fuels in residential-scale appliances will require technological developments in both burners and filtration.

Copyright © 2016 American Association for Aerosol Research     

Untersuchungen zum Abbau von Maillard-Reaktionsprodukten durch amylolytische Enzyme

The enzymatic degradation of thermal treated α-glucans with amylolytic enzymes depends on the reaction environment (T, pH, moisture), the degree of polymerisation (DP) and the branch of the substrates as well as on the presence of amino compounds. The chemical changes of the α-glucans due to thermolysis at 180 °C are characterized by means of the amount of reducing substances and the amount of maltooligosaccharides (HPLC). In general the enzymatic degradability of the thermal treated α-glucans is decreased with increasing time of thermolysis, temperature and moisture content. The enzyme activity with the thermal treated α-glucans is diminished in the same way. The addition of amino compounds reduces the enzymatic degradability only at the beginning of the reaction. With increasing time of thermolysis the thermolysates without glycine addition are hardly degradated. As reason for these differences in the enzymatic degradation transglycosylation and non-enzymatic browning reactions (caramalisation/ Maillard-reaction) are assumed.