Electrochemically induced precipitation enables fresh urine stabilization and facilitates source separation

Source separation of urine can enable nutrient recycling, facilitate wastewater management, and conserve water. Without stabilization of the urine, urea is quickly hydrolyzed into ammonia and (bi)carbonate, causing nutrient loss, clogging of collection systems, ammonia volatilization, and odor nuisance. In this study, electrochemically induced precipitation and stabilization of fresh urine was successfully demonstrated. By recirculating the urine over the cathodic compartment of an electrochemical cell, the pH was increased due to the production of hydroxyl ions at the cathode. The pH increased to 11-12, decreasing calcium and magnesium concentrations by >80%, and minimizing scaling and clogging during downstream processing. At pH 11, urine could be stabilized for one week, while an increase to pH 12 allowed urine storage without urea hydrolysis for >18 months. By a smart selection of membranes [anion exchange membrane (AEM) with a cation exchange membrane (CEM) or a bipolar membrane (BPM)], no chemical input was required in the electrochemical cell and an acidic stream was produced that can be used to periodically rinse the electrochemical cell and toilet. On-site electrochemical treatment, close to the toilet, is a promising new concept to minimize clogging in collection systems by forcing controlled precipitation and to inhibit urea hydrolysis during storage until further treatment in more centralized nutrient recovery plants

Experimental investigation of direct contact baseplate cooling for electric vehicle power electronics

An experimental setup has been built to investigate the thermo-hydraulic performance of the direct contact baseplate cooling technique for power electronics in electric vehicles, to improve the design and to validate the modelling of this technique. The setup consists of an electrical heater to emulate the heat dissipation of the power electronics and which is cooled by a 60/40% mixture by mass of water-glycol. It is equipped with a flow rate sensor, absolute and differential pressure sensors and temperature measurements at the inlet, outlet and baseplate over the channel length, to determine the performance parameters used in the comparison: thermal resistance and pumping power. Three fluid inlet temperatures, four power levels and four flow rates have been tested for three channel heights (1.5mm, 3mm and 7.6mm). Increasing the fluid temperature and/or heating power, results in a lower thermal resistance and pumping power, due to a lower viscosity of the fluid. The performance of the 1.5mm and 7.6mm channel was found to be quite similar, while the 3mm channel results on average in a 5.8% lower thermal resistance compared to the other two channel heights. The heat transfer in terms of the Nusselt number was also evaluated in function of the Reynolds number. By analyzing the hydraulic and thermal entrance lengths it could be concluded that the flow in all measurements is simultaneously developing. A comparison with two correlations from scientific literature for simultaneously developing flow did not show a good agreement, possibly due to the specific inlet and outlet effect, which is more pronounced for a bigger channel height than a smaller channel height

The impact of neighborhood deprivation on patients' unscheduled out-of-hours healthcare seeking behavior: a cross-sectional study

Background: The use of unscheduled out of hours medical care is related to the social status of the patient. However, the social variance in the patient's preference for a hospital based versus a primary care based facility, and the impact of specific patient characteristics such as the travel distance to both types of facilities is unclear. This study aims to determine the social gradient in emergency care seeking behavior (consulting the emergency department (ED) in a hospital or the community-based Primary Care Center (PCC)) taking into account patient characteristics including the geographical distance from the patient's home to both services. Methods: A cross-sectional study, including 7,723 patients seeking out-of-hours care during 16 weekends and 2 public holidays was set up in all EDs and PCCs in Ghent, Belgium. Information on the consulted type of service, and neighborhood deprivation level was collected, but also the exact geographical distance from the patient's home to both types of services, and if the patient has a regular GP. Results: Patients living in a socially deprived area have a higher propensity to choose a hospital-based ED than their counterparts living in more affluent neighborhoods. This social difference persists when taking into account distance to both services, having a regular GP, and being hospitalized or not. The impact of the distance between the patient's home address and the location of both types of services on the patient's choice of service is rather small. Conclusions: Initiatives aiming to lead patients more to PCC by penalizing inappropriate ED use might increase health inequity when they are not twinned with interventions improving the access to primary care services and tackling the underlying mechanisms of patients' emergency care seeking behavior. Further research exploring the impact of out-of-hours care organization (gatekeeping, payment systems, ...) and the patient's perspectives on out-of-hours care services is needed