This paper presents a teaching kit that combines the fabrication of a low-cost microcontroller-based potentiostat and a LabVIEW-generated graphical user interface. The potentiostat enables undergraduate-level students to learn electroanalytical techniques and characterize energy conversion devices such as solar cells. The purpose of this teaching module is to make the introduction of electrochemistry accessible to undergraduate laboratories, especially those with limited financial resources and without expertise in electronics or programming. The electronic circuit components for the potentiostat are readily available and easy to assemble. The graphical user interface replaces any programming-based interface, displays data in real time, and interacts with user commands. The software package is a stand-alone executable file that is compatible with any PC and is provided in the Supporting Information. Cyclic voltammetry, linear sweep voltammetry, and chronoamperometry functions are demonstrated with representative electrochemical experiments, and the data obtained are comparable to those obtained with a research-grade potentiostat. This teaching module is user-friendly so that it can be easily adapted into the undergraduate classroom. We make available in the Supporting Information all of the necessary instructions and information, including schematics for the potentiostat, circuit layout, electronic components, case fabrication, step-by-step instructions for assembly, software user interface, and detailed operating instructions.

Additive manufacturing has transformed the perspective of producing three dimensions (3D) objects toward achieving high quality in terms of accuracy, resolution, and high mechanical integrity with excellent surface finishing in little time compared to subtractive (traditional) production. Vat photopolymerization (VPP) additive manufacturing is among the most common 3D printing technology used in the medical field, academic research, and industrial production of 3D parts. Four main 3D printing techniques fall under VPP, namely continuous liquid interface production (CLIP), daylight polymer printing (DPP), stereolithography (SLA), and digital light processing (DLP). The last two are the focus of the present article. The high accuracy, precision, the unique ability to produce highly complex porous structural geometries, the low printing cost, and the production time of 3D structures compared to subtractive 3D manufacturing make DLP and SLA suitable for medical applications, specifically in regenerative medicine. This review presents the recent trend of DLP and SLA as used in medical research related to bone tissue engineering highlighting the mechanical and biological properties of the resulting 3D bone structures. In addition, photopolymerization mechanisms, photocurable materials, and the working principles of DLP and SLA are introduced.

No abstract

The study sought to establish the relationship between teachers’ workload, class size and students’ academic performance from five selected secondary schools in Singida urban. The study was guided by  three objectives and three research hypotheses. The study employed correlational cross-sectional design. A sample size of two hundred nighty four respondents was randomly chosen from five secondary schools. A self-administered questionnaire was used to collect information from respondents. The collected data were analysed by Statistical Package for Social Scientists (SPSS) using Karl Pearson’s Linear Correlation Coefficient and Multiple Regression Analysis to assess the correlation between teachers’ workload and class size and students’ academic performance. The study results indicated that, there was no significant relationship between teachers’ workload and students’ academic performance in surveying secondary schools in Singida Urban at the five percent level of significance. Further, the findings show that class size was positively correlated with  students’ academic performance in secondary schools in Singida urban. Also,  there is a significant difference between teachers’ work load and class size in relation to students of academic performance in selected secondary schools in Singida urban.  Based on the study findings, it is recommended  that, emphasis should be directed at improving class size if teachers and education stakeholders in Singida urban have to increase students’ academic performance. The study concluded class size is found to be the best predictor of students’ academic performance in the surveyed secondary schools in Singida Urban.

Donor doping is commonly applied for softening of the piezoelectric and dielectric properties and facilitation of polarization switching in the ubiquitous Pb(Zr,Ti)O3 [PZT] ceramics. The origin of the donor‐dopant effects is not entirely clear. (Pb,Ba)ZrO3 [PBZ] is a related ferroelectric material, its perovskite A‐site being partially occupied by the larger Ba+2 cation, less prone to evaporation than Pb+2, and the B‐site is occupied entirely by the valency‐stable Zr+4. Here we report on our studies of Nb+5 doping effects in (Pb,Ba)ZrO3. Similarly, to past observations on La+3 and Nb+5 doped PZT, we find a strong reduction in relative density of PBZ when the doping is <0.5 atomic %. This is accompanied by lattice parameter reduction, enhanced PbO loss, smaller grain size and deterioration of dielectric, piezoelectric and polarization switching properties, the latter being opposite of expected softening effect. All those observations can be interpreted in terms of the Nb entering A‐site at small concentrations. This is supported by ab‐inito calculations and analysis of the possible defect reaction equations. The structure and microstructure of PBZ with Nb>0.2% are consistent with Nb+5 entering the B‐site and softening effects are observed. The study supports the scenario of hardening due to domain walls pinning by VPb‐VO divacancies and softening upon decrease in their concentration.