ASU Scholarship Showcase

Urea is an added value chemical with wide applications in the industry and agriculture. The release of urea waste to the environment affects ecosystem health despite its low toxicity. Online monitoring of urea for industrial applications and environmental health is an unaddressed challenge. Electroanalytical techniques can be a smart integrated solution for online monitoring if sensors can overcome the major barrier associated with long-term stability. Mixed metal oxides have shown excellent stability in environmental conditions with long lasting operational lives. However, these materials have been barely explored for sensing applications. This work presents a proof of concept that demonstrates the applicability of an indirect electroanalytical quantification method of urea. The use of Ti/RuO2-TiO2-SnO2 dimensional stable anode (DSA®) can provide accurate and sensitive quantification of urea in aqueous samples exploiting the excellent catalytic properties of DSA® on the electrogeneration of active chlorine species. The cathodic reduction of accumulated HClO/ClO− from anodic electrogeneration presented a direct relationship with urea concentration. This novel method can allow urea quantification with a competitive LOD of 1.83 × 10−6 mol L−1 within a linear range of 6.66 × 10−6 to 3.33 × 10−4 mol L−1 of urea concentration.

Does school participatory budgeting (SPB) increase students’ political efficacy? SPB, which is implemented in thousands of schools around the world, is a democratic process of deliberation and decision-making in which students determine how to spend a portion of the school’s budget. We examined the impact of SPB on political efficacy in one middle school in Arizona. Our participants’ (n = 28) responses on survey items designed to measure self-perceived growth in political efficacy indicated a large effect size (Cohen’s d = 1.46), suggesting that SPB is an effective approach to civic pedagogy, with promising prospects for developing students’ political efficacy.

In-process laser heating technique delivers a cost-efficient way to improve mechanical and geometrical properties to nearly isotropic and extremely smooth, respectively. The technique involves the incorperation of a solid-state laser into a commercial off-the-shelf 3D printer, mechanical system to allow controllable laser allumination on desired surfaces, and a gcode postprocesser to proper control of the mechanical system. This process uses laser for local heating, to enhance mass transfer between boundaries or to enhance surface reflow to smooth surface irregularity, to improve mechanical and geometrical properties. Only less than 3 W of laser power (CO2 laser) was used for high temperature material like PEEK and Ultem; less than 1 W (808nm laser) was found to be sufficient for achieving optimal properties for PLA. This technique has the potential for after-market integration into most commercial FFF 3D printers to achieved nearly isotropic and smooth 3D printed objects with various thermoplastic polymers.