In order to provide students with the training required to meet the substantial and diverse challenges of the 21st Century, effective programs in engineering, science, and technology must continue to take the lead in developing high-impact educational practices. Over the past year, faculty across several departments collaborated in the establishment of a campus 3D printing and fabrication center. This facility was founded to offer opportunities for exploring innovative active learning strategies in order to enhance the lives of Wabash College students and serve as a model to other institutions of higher education. This campus resource provides the infrastructure that will empower faculty and staff to explore diverse and meaningful cross-disciplinary collaborations related to teaching and learning across campus. New initiatives include the development of courses on design and fabrication, collaborative cross-disciplinary projects that bridge courses in the arts and sciences, 3D printing and fabrication-based undergraduate research internships, and entrepreneurial collaborations with local industry. These innovative approaches are meant to open the door to greater active learning experiences that empower and prepare students for creative and practical problem solving. Furthermore, service learning projects, community-based opportunities, and global outreach initiatives provide students with a sense of social responsibility, ethical awareness, leadership, and teamwork. This paper shares initial successes of this effort and goals for future enrichment of student learning.

In order to reduce the material cost for silicon solar cells, several research groups are investigating methods to minimize the silicon consumption for making monocrystalline silicon wafers. One promising approach is deposition of an epitaxial layer on porous silicon, followed by detachment of the layer. This contribution discusses improvements in the epitaxial wafer fabrication by optimization of the porosification process. The introduction of a layered porous silicon structure allows to independently improve both epitaxial layer quality and detachment yield. In this way, we have managed to obtain 100µm thick silicon wafers with effective lifetimes up to 1.3ms, and 40µm thick wafers with effective lifetimes up to 700µs. We will also review the current status of the process development for solar cells made on thin wafers. Two approaches are presented. In the first approach, heterojunction solar cells are fabricated on freestanding epitaxial wafers of 40µm thickness. In the second approach, high efficiency (21%) heterojunction back-contacted cells are fabricated on wafers that are bonded to a glass superstrate. Challenges for device processing and limitations in cell performance are discussed.

Four decades of advanced research about Non-Conventional Materials and Technologies (NOCMAT) such as bamboo and composites reinforced with natural fibers have shown that it is now possible to produce and use high performance NOCMAT. Bamboo and composites reinforced with vegetable fibers are capable, meeting most engineering demand in terms of strength, stiffness, toughness and energy absorption capability. The greatest challenge of the 21st century is the need for cost-effective, durable and eco-friendly construction materials that will meet the global needs of infrastructure regeneration and rehabilitation which alone can enhance the quality of life for all the people of the world. This paper summarizes some results of judicious combination of different matrix reinforced with vegetable fibers, especially bamboo. These sustainable ecological materials are strong, ductile and capable of absorbing large amounts of energy. They could find extensive applications in the engineering particularly in developing countries. Specifically, the development of durable composites reinforced with vegetable fibers and bamboo poses an important challenge to the science and skills of engineering. This challenge could create the most useful, eco-friendly construction materials backed by an endless supply of renewable natural resources. In addition the paper presents results of some ongoing research concerning bamboo and how vegetable fibers such as hemp plant, before the invention of Nylon was the most used materials in all aspects of human life around the globe and why it was banned.

The emergence of hydrogen and fuel cell technologies in transportation and stationary power sectors offers the world important and potentially transformative environmental and energy security benefits. In recent years, research supported by the U.S. Department of Energy’s (DOE) Fuel Cell Technologies Office has contributed substantially to the development of these technologies. Enhanced performance and reduced cost in automotive fuel cells are important examples of achievement. The research investments are clearly paying off, as commercial fuel-cell electric vehicles (FCEVs) are being rolled out by major car manufacturers today. With increasing market penetration of FCEVs, enabling technologies for the affordable and widespread production, storage and delivery of renewable hydrogen are becoming increasingly important. Long term commercial viability of hydrogen and fuel cells in the commercial marketplace will rely on continued materials research on several important fronts. Examples include the discovery and development of: (1) non-platinum-group-metal catalysts for next-generation fuel cells; (2) durable, high-performance photocatalytic materials systems for direct solar water splitting; (3) advanced materials-based systems for low-pressure, high-volumetric-density hydrogen storage; and (4) low-cost, hydrogen-compatible pipeline materials for hydrogen delivery and distribution. Research innovations in macro-, meso- and nano-scale materials are all needed for pushing forward the state-of-the-art in these areas. New approaches in accelerated materials development facilitated by a national Energy Materials Network of advanced scientific resources in theory, computation and experimentation are being adopted at DOE. Application of these approaches to address the key materials challenges in hydrogen and fuel cell technologies are discussed.

Whispering gallery modes (WGMs) have been widely studied over the past 20 years for various applications, including biological sensing. While the WGM-based sensing approaches reported in the literature have shown tremendous performance down to single molecule detection, at present such sensing technologies are not yet mature and still have significant practical constraints that limit their use in real-world applications. Our work has focused on developing a practical, yet effective, WGM-based sensing platform capable of being used as a dip sensor for in-vivo biosensing by combining WGM fluorescent microresonators with silica Microstructured Optical Fibers (MOFs).

We recently demonstrated that a suspended core MOF with a dye-doped polymer microresonator supporting WGMs positioned onto the tip of the fiber, can be used as a dip sensor. In this architecture the resonator is anchored to one of the MOF air holes, in contact with the fiber core, enabling a significant portion of the evanescent field from the fiber to overlap with the sphere and hence excite the fluorescent WGMs. This architecture allows for remote excitation and collection of the WGMs. The fiber also permits easy manipulation of the microresonator for dip sensing applications, and hence alleviates the need for a complex microfluidic interface. More importantly, it allows for an increase in both the excitation and collection efficiency compared to free space coupling, and also improves the Q factor.

In this paper we present our recent results on microstructured fiber tip WGM-based sensors and show that this sensing platform can be used in clinical diagnostics, for detecting various clinically relevant biomarkers in complex clinical samples.

Complex oxides and semiconductors exhibit distinct yet complementary propertiesowing to their respective ionic and covalent natures. By electrically couplingoxides to semiconductors within epitaxial heterostructures, enhanced or novelfunctionalities beyond those of the constituent materials can potentially berealized. Key to electrically coupling oxides to semiconductors is controllingthe physical and electronic structure of semiconductor – crystallineoxide heterostructures. Here we discuss how composition of the oxide can bemanipulated to control physical and electronic structure inBa1-xSrxTiO3/ Ge andSrZrxTi1-xO3/Ge heterostructures. In thecase of the former we discuss how strain can be engineered through compositionto enable the re-orientable ferroelectric polarization to be coupled to carriersin the semiconductor. In the case of the latter we discuss how composition canbe exploited to control the band offset at the semiconductor - oxide interface.The ability to control the band offset, i.e. band-gap engineering, provides apathway to electrically couple crystalline oxides to semiconductors to realize ahost of functionalities.

Phase separation of InxGa1-xN alloys into Ga-rich and In-rich regions was observed by a number of research groups for samples grown with high indium content, x. Due to the radiation sensitivity of InGaN to beam damage by fast electrons, high-resolution imaging in transmission electron microscopy (TEM) or core-loss electron energy-loss spectroscopy (EELS) may lead to erroneous results. Low-loss EELS can yield spectra of the plasmon loss regions at much lower electron fluxes. Unfortunately, due to their delayed edge onset, the low energetic core losses of Ga and In partially overlap with the plasmon peaks, all of which shift with indium content.

Here we demonstrate a method to quantify phase separation in InGaN thin films from the low-loss region in EELS by simultaneously fitting both plasmon and core losses over the energy range of 13-30eV. Phase separation is shown to lead to a broadening of the plasmon peak and the overlapping core losses, resulting in an unreliable determination of the indium concentration from analyzing the plasmon peak position alone if phase separation is present. For x=0.3 and x=0.59, the relative contributions of the binary compounds are negligibly small and indicate random alloys. For x nom.=0.62 we observed strong broadening, indicating phase separation.

Cancer cell metastasis is a leading cause of mortality whereby cancer cells migrate from a tumor and spread to distant sites in the body. Understanding metastasis requires a deeper understanding of biomechanics and mechanobiology at the cellular level. We have established the use of Atomic Force Microscopy to infer the mechanical properties of single cells in cultures by measurement of their Young’s modulus. Here we discuss the main advantages, challenges, technological limitations and applicability of AFM based cell mechanics studies along with other emerging high throughput techniques for the development of single cell mechanical based clinical assays for cancer detection and management.

In recent years titanium nitride is being considered as a very promisingplasmonic material for data storage applications as it exhibits a pronouncedplasmonic dipolar resonance and has high thermal stability. However, there is alack of research where higher order resonance modes are examined. We addressthis here by performing angle dependent spectral transmission measurementsnanodisks arrays made from titanium nitride. The measurements show strongpolarization dependence with s-polarized light causing excitation of thequadrupole and higher order resonance plasmonic modes. These higher order modesare required for the state-of-the-art designs of near-field transducers. This,together with its outstanding thermal properties, makes TiN a favourablematerial for data storage applications.

Complex three-dimensional (3-D) super structural TiO2 architectures with controlled shape and size were synthesized by a facile hydrothermal synthesis route by using titanium tetrachloride (TiCl4) as the metal precursor and hydrochloric acid (HCl)/ammonium chloride (NH4Cl) as the mineralizer/structure directing agent. Several interesting hierarchical architectures like: (i) nanoparticles assembled spheres (NPAS), (ii) nanowires assembled spheres (NWAS), (iii) nanorods assembled spheres (NRAS), and (iv) nanosheets assembled spheres (NSAS) were achieved by the controlled variation of crystal structure modifier. The synthesized materials were characterised in detail by different analytical techniques and the findings are consistent. To demonstrate the superior performances of the as prepared materials the photocatalytic and photo-voltaic performances were investigated. The results demonstrate that these synthesized materials exhibits enhanced photocatalytic activity (efficiency is ∼ 91%) towards the degradation of RhB and as a photoanode in DSSCs the maximum energy conversion efficiency is ∼5%, attributed primarily to the unique hierarchical mesoporous structure of the TiO2 architectures.

The variation of the electrical and optical properties under 150 keV Ar+ ion irradiation has been studied in Ge2Sb2Te5 polycrystalline films, either in the rocksalt or in the trigonal structure, by in situ reflectivity measurements and ex situ resistance measurements. As the irradiation dose increases, the disorder introduced in the crystalline films increases and the reflectivity decreases, down to a minimum value that corresponds to complete amorphization. Large differences are found by changing the irradiation temperature, for the two crystalline structures. Indeed, the measured amorphization threshold is the same for the two crystalline phases and equal to 1x1013 cm-2 under irradiation at 77K, whilst at room temperature the trigonal phase requires a dose almost double than the rocksalt phase to be amorphized. By structural analyses we found that, before amorphization, ion irradiation induces a transition from the trigonal to the rocksalt structure. The van der Waals gaps present in the trigonal phase might act as preferential sinks for the displaced and mobile atoms, thus promoting this transition. By further increasing the irradiation dose the formed disordered rocksalt phase converts into the amorphous phase. Ion irradiation also affects the electrical properties of the material: the disorder modifies the temperature dependence of resistance of the trigonal Ge2Sb2Te5 and induces a change of sign (from metallic to insulating behavior) at a dose of 2x1013 cm-2, well below the amorphization threshold.

A high-throughput crystallographic investigation on several crystals of photosynthetic reaction center covalently bound to an ad-hoc synthesized artificial antenna (AE600) is presented. The investigation did not show a preferential binding site of the antenna molecule AE600 to the reaction center in the solid phase. An accurate crystallographic study allowed identifying a lysine residue sitting on periplasmic side of the protein as one of the bioconjugation sites. The residue sits on subunit M of the protein, in close proximity to the bacteriochlorophylls of the reaction center involved in the light absorption and conversion processes. Distances obtained from the crystallographic structure confirm that energy transfer between the antenna and the protein proceed with the Förster resonance mechanism.

Model polyamide thin films were prepared through a controlled interfacial polymerization route known as molecular layer by layer (mLbL). Films were synthesized directly onto quartz crystals and subjected to halogenated aqueous environments that are known to cause degradation of the amide network. A quartz crystal microbalance (QCM) was used as the detection platform to ascertain mass loss due to degradation in real time. X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) measurements were also performed at various stages of the degradation sequence to elucidate the chemical and morphological changes at the surfaces respectively. Appropriate strategies for accurately comparing material degradation resistance are proposed along with modifications to the crosslinked polyamide chemistry to produce more halogen tolerant polymeric surfaces.

Iron nitride thin films have potential applications in the biomedicine andenergy. The magnetic properties of these films can be tuned by incorporatingcopper nitride. In this study, iron copper nitride thin films have beenfabricated by magnetron sputtering technique either by co-sputtering ironnitride and copper nitride or by layer stacking of the materials. The structure,morphology and magnetic properties of the films have been studied by scanningelectron microscopy, x-ray diffraction, x-ray reflectivity and vibrating samplemagnetometry.

Microindentation is performed on hot isostatic pressed (HIP) Mg-Al (AM40) alloy samples produced by high-pressure die cast (HPDC) process for the purpose of quantifying the mechanical properties of the α-Mg grains. The process of obtaining elastic modulus and hardness from indentation load-depth curves is well established in the literature. A new inverse method is developed to extract plastic properties in this study. The method utilizes empirical yield strength-hardness relationship reported in the literature together with finite element modeling of the individual indentation. Due to the shallow depth of the indentation, indentation size effect (ISE) is taken into account when determining plastic properties. The stress versus strain behavior is determined for a series of indents. The resulting average values and standard deviations are obtained for future use as input distributions for microstructure-based property prediction of AM40.

‘Regenerative Engineering’ is the integration of advanced materials science, stem cell science, physics, developmental biology and clinical translation to regenerate complex tissues and organ systems. Advanced biomaterial and stem cell science converge as mechanisms to guide regeneration and the development of prescribed cell lineages from undifferentiated stem cell populations. Studies in somite development and tissue specification have provided significant insight into pathways of biological regulation responsible for tissue determination, especially morphogen gradients, and paracrine and contact-dependent signaling. The understanding of developmental biology mechanisms are shifting the biomaterial design paradigm by the incorporation of molecules into scaffold design and biomaterial development that are specifically targeted to promote the regeneration of soft tissues. Our understanding allows the selective control of cell sensitivity, and a temporal and spatial arrangement to modulate the wound healing mechanism, and the development of cell phenotype leading to the patterning of distinct and multi-scale tissue systems.

Building on the development of mechanically compliant novel biomaterials, the integration of spatiotemporal control of biological, chemical and mechanical cues helps to modulate the stem cell niche and direct the differentiation of stem cell lineages. We have developed advanced biomaterials and biomimetic scaffold designs that can recapitulate the native tissue structure and mechanical compliance of soft musculoskeletal tissues, such as woven scaffold systems for ACL regeneration, non-woven scaffolds for rotator cuff tendon augmentation, and porous elastomers for regeneration of muscle tissue. Studies have clearly demonstrated the modulation of stem cell response to bulk biomaterial properties, such as toughness and elasticity, and scaffold structure, such as nanoscale and microscale dimensions. The integration of biological cues inspired from our understanding of developmental biology, along with chemical, mechanical and electrical stimulation drives our development of novel biomaterials aimed at specifying the stem cell lineage within 3-dimensional (3D) tissue systems. This talk will cover the development of biological cues, advanced biomaterials, and scaffold designs for the regeneration of complex soft musculoskeletal tissue systems such as ligament, tendon, and muscle.

We report herein a facile approach to synthesize processable bimetallic nanoparticles (Pd-Au/AuPd/Ag-Au/Au-Ag) decorated Prussian blue nanocomposite (PB-AgNP). The presence of cyclohexanone/formaldehyde facilitates the formation of functional bimetallic nanoparticles from 3-aminopropyltrimethoxysilane (3-APTMS) capped desired ratio of hetero noble metal ions. The use of 3-APTMS and cyclohexanone also enables the synthesis of polycrystalline Prussian blue nanoparticles (PBNPs). As synthesized PBNPs, Pd-Au/Au-Pd/Ag-Au/Au-Ag enable the formation of nano-structured composites displaying better catalytic activity than that recorded with natural enzyme. The nanomaterials have been characterized by Uv-Vis, FT-IR and Transmission Electron Microscopy (TEM) with following major findings: (1) 3-APTMS capped noble metal ions in the presence of suitable organic reducing agents i.e.; 3 glycidoxypropyltrimethoxysilane (GPTMS), cyclohexanone and formaldehyde; are converted into respective nanoparticles under ambient conditions, (2) the time course of synthesis and dispersibility of the nanoparticles are found as a function of organic reducing agents, (3) the use of formaldehyde and cyclohexanone in place of GPTMS with 3-APTMS outclasses the other two in imparting better stability of amphiphilic nanoparticles with reduced silanol content, (4) simultaneous synthesis of bimetallic nanoparticles under desired ratio of palladium/gold and silver/ gold cations are recorded, (5) the nanoparticles made from the use of 3-APTMS and cyclohexanone enable the formation of homogeneous nanocomposite with PBNP as peroxidase mimetic representing potential substitute of peroxidase enzyme. The peroxidase mimetic ability has been found to vary as a function of 3-APTMS concentration revealing the potential role of functional metal nanoparticles in bioanalytical applications.

A highly accurate multi-point pressure measurement system based on MEMS pressure sensors spliced into a fiber optic cable and suitable for downhole deployment in a CO2 sequestration well was designed, developed and tested in the laboratory. An interrogator system based on a pulsed laser excitation was shown to be capable of multiple (potentially 60+) point sensor measurements on a single fiber. The interrogator was interfaced with the GE PredixTM industrial internet to demonstrate a remote monitoring system. Sensor packages were fabricated and tested at high temperatures and pressures in supercritical CO2. Environmental and stress testing of the sensor components and package indicated areas in which the design of the package should be further improved.

Thin GaAs photovoltaic heterostructures are grown by MOCVD with various p-GaAs base thicknesses. The total n/p absorbing thickness is varied systematically. Output voltages up to ∼1.155V were obtained for individual n/p junctions at an average illumination intensity of ∼8W/cm2. Novel phototransducer devices are then achieved with a vertical epitaxial heterostructure architecture, monolithically integrating 5 or more such thin n/p junctions. Around the design wavelength, the stacked heterostructure design is yielding an optimal external quantum efficiency approaching unity divided by the number of junctions. The modeled and measured conversion efficiencies are exceeding 60%. The photocarrier extraction properties are simulated for different junction thicknesses using a model based on a 3-dimensional (3D) radially-symmetric TCAD implementation of the heterostructures. The study clearly demonstrates that for such thin n/p junctions the photocarrier extraction can still be efficient due to the operation at reduced current densities and higher voltages in heterostructures enhancing electrical power extraction. With the supplementary add-on of a window layer with a reduced sheet resistance for the stacked structure, we demonstrate the possible efficient operation of phototransducers for optical inputs exceeding 150 W/cm2, even for the case of devices designed without gridlines.

The electronic structure of PuB6, an actinide analog of SmB6 , was investigated making use of a combination of the density functional theory (DFT), and the exact diagonalization (ED) of an effective discrete Anderson impurity model. Intermediate valence ground state with the f-shell occupation n4f =5.5 for the Pu atom in PuB6 is calculated. The 5f-shell magnetic moment is completely compensated by the moment carried by the electrons in the conduction band. Already in DFT, PuB6 is an insulator with a small amount of holes near the X-point, and the indirect band gap of ≈60 meV. This band gap becomes direct in DFT+ED calculations supporting the idea of “topological Kondo insulator” in PuB6. Connection between the electronic structure of PuB6 and δ-Pu is established. We propose that these materials belong to a new class of intermediate valence “Racah” materials with the multi-orbital “Kondo-like” singlet ground-state.