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Debugging is a challenging task for novice programmers in computer science courses and calls for specific investigation and support. Although the debugging process has been explored with qualitative methods and log data analyses, the detailed code changes that describe the evolution of debugging behaviors as students gain more experience remain relatively unexplored. In this study, we elicited “constituents” of the debugging process based on experts’ interpretation of students’ debugging behaviors in an introductory computer science (CS1) course. Epistemic Network Analysis (ENA) was used to study episodes where students fixed syntax/checkstyle errors or test errors. We compared epistemic networks between students with different prior programming experience and investigated how the networks evolved as students gained more experience throughout the semester. The ENA revealed that novices and experienced students put different emphasis on fixing checkstyle or syntax errors and highlighted interesting constituent co-occurrences that we investigated through further descriptive and statistical analyses. 

Debugging is a challenging task for novice programmers in computer science courses and calls for specific investigation and support. Although the debugging process has been explored with qualitative methods and log data analyses, the detailed code changes that describe the evolution of debugging behaviors as students gain more experience remain relatively unexplored. In this study, we elicited “constituents” of the debugging process based on experts’ interpretation of students’ debugging behaviors in an introductory computer science (CS1) course. Epistemic Network Analysis (ENA) was used to study episodes where students fixed syntax/checkstyle errors or test errors. We compared epistemic networks between students with different prior programming experience and investigated how the networks evolved as students gained more experience throughout the semester. The ENA revealed that novices and experienced students put different emphasis on fixing checkstyle or syntax errors and highlighted interesting constituent co-occurrences that we investigated through further descriptive and statistical analyses. 

Electrically accelerated self‐healable poly(ionic liquids) copolymers that exhibit resistor‐capacitor (RC) circuit properties are developed. At low alternating current (AC) frequencies these materials behave as a resistor (R), whereas at higher frequencies as a capacitor (C). These properties are attributed to a combination of dipolar and electrostatic interactions in (1‐[(2‐methacryloyloxy)ethyl]‐3‐butylimidazolium bis(trifluoromethyl‐sulfonyl)imide) copolymerized with methyl methacrylate (MMA) monomers to form p(MEBIm‐TSFI/MMA)] copolymers. When the monomer molar ratio (MEBIm‐TSFI:MMA) is 40/60, these copolymers are capable of undergoing multiple damage‐repair cycles and self‐healing is accelerated by the application of alternating 1.0–4.0 V electric field (EF). Self‐healing in the absence of EFs is facilitated by van der Waals (vdW) interactions, but the application of AC EF induces back and forth movement of charges against the opposing force that result in dithering of electrostatic dipoles giving rise to interchain physical crosslinks. Electrostatic inter‐ and intrachain interactions facilitated by copolymerization of ionic liquid monomers with typically dielectric acrylic‐based monomers result in enhanced cohesive energy densities that accelerate the recovery of vdW forces facilitating self‐healing. Incorporating ionic liquids into commodity polymers offers promising uses as green conducting solid polyelectrolytes in self‐healable energy storage, energy‐harvesting devices, and many other applications.

 

Three-dimensional (3D) printing allows for creation of patient-specific implants. However, development of new synthetic materials for 3D printing has been relatively slow with only a few polymers available for tissue engineering applications. Most of these polymers require harsh processing conditions like high temperatures and pressures or are mixed with a combination of leachable additives like plasticizers, initiators, crosslinkers, and solvents to enable 3D printing. Therefore, to propel the development of new polymers for ambient temperature, additive-free 3D printing it is necessary to systematically understand the relationship between the structure of a polymer with its 3D printability. Herein, three homopolyesters were synthesized, each with a common backbone but differing in the length of their saturated, aliphatic pendant chains with 2, 6, or 15 carbons. The physical properties such as the glass transition temperature ( T g ) and the rheological properties like shear thinning, temperature response, and stress relaxation were correlated to the individual polymer's 3D printability. The 3D printability of the polymers was assessed based on four criteria: ability to be extruded as continuous filaments, shape fidelity, the retention of printed shape, and the ability to form free hanging filaments. We observed that the polymers with longer side chains can be extruded at low temperature and pressure because the long side chains act as internal diluents and increase the flowability of the polymer. However, their ability to retain the 3D printed shape is adversely affected by the increase in side chain length, unless the side chains form ordered structures leading to immediate recovery of viscosity. The insight derived from the systematic investigation of the effect of polymer structure on their rheology and 3D printability can be used to rationally design other polymers for extrusion-based direct-write 3D printing. 

Known for their adaptability to surroundings, capability of transport control of molecules, or the ability of converting one type of energy to another as a result of external or internal stimuli, responsive polymers play a significant role in advancing scientific discoveries that may lead to an array of diverge applications. This review outlines recent advances in the developments of selected commodity polymers equipped with stimuli‐responsiveness to temperature, pH, ionic strength, enzyme or glucose levels, carbon dioxide, water, redox agents, electromagnetic radiation, or electric and magnetic fields. Utilized diverse applications ranging from drug delivery to biosensing, dynamic structural components to color‐changing coatings, this review focuses on commodity acrylics, epoxies, esters, carbonates, urethanes, and siloxane‐based polymers containing responsive elements built into their architecture. In the context of stimuli‐responsive chemistries, current technological advances as well as a critical outline of future opportunities and applications are also tackled.