This paper is a report on the demonstration and stabilization of a 2x4 NbN hot electron bolometer (HEB) array receiver for GUSTO based on a multiple beam local oscillator (LO). Through the combination of a FIR Gas laser and a Fourier phase grating we were able to generate a 8 beam pattern at 1.4 THz. For the array demonstration, it used a 2x2 HEB mixer array which was translated vertically to match the full 2x4 LO beam pattern. Here two lens with a 60 mm were applied to reduce the beam pattern divergence, allowing for a 12 mm spacing between the beams to be achieved at 130 mm from the grating. To stabilize the array receiver, we introduced a new stabilization method, requiring only a voice coil PID controlled loop between the beam originated from the gas laser and a given pumped pixel. The total power Allan time measurements indicate a five times improvement on a two-pixel system stability.@en

Cycle paths can be used as a route for active transportation or simply to cycle for physical activity and leisure. However, exposure to air pollutants can be boosted while cycling, in urban environments, due to the proximity to vehicular emissions and elevated breathing rates. The objective of this work was to assess the exposure of a cyclist to particles and to chemical elements by combining real-time aerosol mass concentration reading equipment and biomonitoring techniques. PM10 and PM2.5 were measured on three cycle paths located in Lisbon, during weekdays and weekends and during rush hours and off-peak hours resulting in a total of 60 campaigns. Lichens were exposed along cycle paths for 3 months, and their element contents were measured by instrumental neutron activation analysis using the k0 methodology (k0-INAA). Using a bicycle commute route of lower traffic intensity and avoiding rush hours or other times with elevated vehicular congestion facilitate a reduction in exposure to pollutants. The implementation of cycle paths in cities is important to stimulate physical activity and active transportation; however, it is essential to consider ambient air and pollutant sources to create safer infrastructures.@en