Strategic Growth Area: Economical and Sustainable Materials (ESM)
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- Intra-Ring Compression Strength of Low Density HardwoodsZink-Sharp, Audrey G.; Price, Carlile (Universidad del Bío-Bío, 2006)Engineered wood composites are being crafted with increasingly smaller and smaller components, yet a search of the literature indicates a lack of intra-ring mechanical property data for almost all commercial wood types, particularly the underutilized low density hardwoods. In addition, there is no universally accepted testing regime for determining micromechanical properties of wood samples. As a result, we developed a testing system for determining compression, tension, and bending properties of growth ring regions of wood samples. Our microtesting system consists of a 45.4 kg load stage, motor drive, data acquisition system, motor control, load cell, strain transducer, and software. In this study, intra-ring compression strength parallel to the grain was determined for small samples (a few ml3 in volume) of sweetgum (Liquidambar styraciflua), yellow-poplar (Liriodendron tulipifera), and red maple (Acer rubrum). It was determined that compression strength is weakly correlated with specific gravity but unrelated to growth rate. Specific gravity was also unrelated to growth rate. Sweetgum values were intermediate between yellow-poplar and red maple.
- Multimodal system for harvesting magnetic and mechanical energyDong, Shuxiang; Zhai, Junyi; Li, Jiefang; Viehland, Dwight D.; Priya, Shashank (AIP Publishing, 2008-09-01)In this letter, we investigate a multimodal system for simultaneous energy harvesting from stray magnetic and mechanical energies by combining magnetoelectric and piezoelectric effects. The system consists of a cantilever beam with tip mass and a magnetoelectric laminate attached in the center of the beam. At 2 Oe magnetic field and mechanical vibration amplitude of 50mg, both at frequency of 20 Hz, the system was found to generate open circuit output voltage of 8 V(P.P.). An equivalent circuit model is proposed that predicts a summation effect for both mechanical and magnetic energies. (c) 2008 American Institute of Physics.
- Network structure and thermal stability study of high temperature seal glassLu, Kathy; Mahapatra, Manoj K. (American Institute of Physics, 2008-10-01)High temperature seal glass has stringent requirement on glass thermal stability, which is dictated by glass network structures. In this study, a SrO-La2O3-Al2O3-B2O3-SiO2 based glass system was studied using nuclear magnetic resonance, Raman spectroscopy, and x-ray diffraction for solid oxide cell application purpose. Glass structural unit neighboring environment and local ordering were evaluated. Glass network connectivity as well as silicon and boron glass former coordination were calculated for different B2O3:SiO2 ratios. Thermal stability of the borosilicate glasses was studied after thermal treatment at 850 degrees C. The study shows that high B2O3 content induces BO4 and SiO4 structural unit ordering, increases glass localized inhomogeneity, decreases glass network connectivity, and causes devitrification. Glass modifiers interact with either silicon- or boron-containing structural units and form different devitrified phases at different B2O3:SiO2 ratios. B2O3-free glass shows the best thermal stability among the studied compositions, remaining stable after thermal treatment for 200 h at 850 degrees C. (C) 2008 American Institute of Physics. [DOI: 10.1063/1.2979323]
- MAPSustain: Visualising biomass and biofuel researchZoss, Angela; Kong, Chin Hua; Ma, Nianli; Börner, Katy (University of Huddersfield, 2010-03-11)This paper discusses the visual and interaction design of an online website that supports the interactive exploration of research on biomass and biofuel research. The dataset used covers 13,506 publication records from MEDLINE, the Department of Energy (DOE) and Thomson Reuter's Web of Science (ISI), as well as the United States Patent and Trademark Office (USPTO) patents, and funding by the National Science Foundation (NSF), the National Institutes of Health (NIH), and the US Department of Agriculture (USDA) for the years 1965 to 2010 (see details in Kong et al., forthcoming). The analyses and visualisations reveal where research and development (R&D) takes place in the United States and also in topic space. Results aim to guide researchers gaining an overview of relevant expertise and research, industry representatives interested in identifying potential collaborators and competitors, or agencies interested in supporting or promoting a specific area of sustainability research.
- Magnetoelectric Interactions in Lead-Based and Lead-Free CompositesBichurin, Mirza I.; Petrov, Vladimir M.; Zakharov, Anatoly; Kovalenko, Denis; Yang, Su-Chul; Maurya, Deepam; Bedekar, Vishwas; Priya, Shashank (MDPI, 2011-04-06)Magnetoelectric (ME) composites that simultaneously exhibit ferroelectricity and ferromagnetism have recently gained significant attention as evident by the increasing number of publications. These research activities are direct results of the fact that multiferroic magnetoelectrics offer significant technological promise for multiple devices. Appropriate choice of phases with co-firing capability, magnetostriction and piezoelectric coefficient, such as Ni-PZT and NZFO-PZT, has resulted in fabrication of prototype components that promise transition. In this manuscript, we report the properties of Ni-PZT and NZFO-PZT composites in terms of ME voltage coefficients as a function of frequency and magnetic DC bias. In order to overcome the problem of toxicity of lead, we have conducted experiments with Pb-free piezoelectric compositions. Results are presented on the magnetoelectric performance of Ni-NKN, Ni-NBTBT and NZFO-NKN, NZFO-NBTBT systems illustrating their importance as an environmentally friendly alternative.
- Sustainable Biomaterials Newsletter, v.7 (July/August 2012)(Department of Sustainable Biomaterials, 2012)
- Sustainable Biomaterials Newsletter, v.7 (May/June 2012)(Department of Sustainable Biomaterials, 2012)
- Food Digest : 2012Virginia Tech. Food Science and Technology Department (Virginia Tech. Food Science and Technology Department, 2012)In December, Virginia Tech broke ground for the first building in the new Biosciences Precinct at the corner of Duck Pond Drive and Washington Street. The 93,860-square-foot building will incorporate laboratory and support facilities, focusing on a wide range of microbiological and biochemical research. Researchers will benefit from the expanded space, which will house research programs on food safety, food packaging and processing, environmental quality analysis, bioenergy and biomaterials, systems biology, and nanotechnology, among other areas.
- Sustainable Biomaterials Newsletter, v.7 (Fall 2012)(Department of Sustainable Biomaterials, 2012)
- Progress in Dual (Piezoelectric-Magnetostrictive) Phase Magnetoelectric Sintered CompositesIslam, Rashed Adnan; Priya, Shashank (Hindawi, 2012-04-04)The primary aims of this review article are (a) to develop the fundamental understanding of ME behavior in perovskite piezoelectric-spinel magnetostrictive composite systems, (b) to identify the role of composition, microstructural variables, phase transformations, composite geometry, and postsintering heat treatment on ME coefficient, and (c) to synthesize, characterize, and utilize the high ME coefficient composite. The desired range of ME coefficient in the sintered composite is 0.5–1 V/cm⋅Oe. The studies showed that the soft piezoelectric phase quantified by smaller elastic modulus, large grain size of piezoelectric phase (~1 μm), and layered structures yields higher magnitude of ME coefficient. It is also found that postsintering thermal treatment such as annealing and aging alters the magnitude of magnetization providing an increase in the magnitude of ME coefficient. A trilayer composite was synthesized using pressure-assisted sintering with soft phase [0.9 PZT–0.1 PZN] having grain size larger than 1 μm and soft ferromagnetic phase of composition Ni0.8Cu0.2Zn0.2Fe2O4 [NCZF]. The composite showed a high ME coefficient of 412 and 494 mV/cm⋅Oe after sintering and annealing, respectively. Optimized ferrite to PZT thickness ratio was found to be 5.33, providing ME coefficient of 525 mV/cm⋅Oe. The ME coefficient exhibited orientation dependence with respect to applied magnetic field. Multilayering the PZT layer increased the magnitude of ME coefficient to 782 mV/cm⋅Oe. Piezoelectric grain texturing and nanoparticulate assembly techniques were incorporated with the layered geometry. It was found that with moderate texturing, d33 and ME coefficient reached up to 325 pC/N and 878 mV/cm⋅Oe, respectively. Nanoparticulate core shell assembly shows the promise for achieving large ME coefficient in the sintered composites. A systematic relationship between composition, microstructure, geometry, and properties is presented which will lead to development of high-performance magnetoelectric materials.
- Broadband/Wideband Magnetoelectric ResponsePark, Chee-Sung; Priya, Shashank (Hindawi, 2012-04-08)A broadband/wideband magnetoelectric (ME) composite offers new opportunities for sensing wide ranges of both DC and AC magnetic fields. The broadband/wideband behavior is characterized by flat ME response over a given AC frequency range and DC magnetic bias. The structure proposed in this study operates in the longitudinal-transversal (L-T) mode. In this paper, we provide information on (i) how to design broadband/wideband ME sensors and (ii) how to control the magnitude of ME response over a desired frequency and DC bias regime. A systematic study was conducted to identify the factors affecting the broadband/wideband behavior by developing experimental models and validating them against the predictions made through finite element modeling. A working prototype of the sensor with flat bands for both DC and AC magnetic field conditions was successfully obtained. These results are quite promising for practical applications such as current probe, low-frequency magnetic field sensing, and ME energy harvester.
- Membranes in Lithium Ion BatteriesYang, Min; Hou, Junbo (MDPI, 2012-07-04)Lithium ion batteries have proven themselves the main choice of power sources for portable electronics. Besides consumer electronics, lithium ion batteries are also growing in popularity for military, electric vehicle, and aerospace applications. The present review attempts to summarize the knowledge about some selected membranes in lithium ion batteries. Based on the type of electrolyte used, literature concerning ceramic-glass and polymer solid ion conductors, microporous filter type separators and polymer gel based membranes is reviewed.
- Harvesting Energy from the Counterbalancing (Weaving) Movement in Bicycle RidingYang, Yoonseok; Yeo, Jeongjin; Priya, Shashank (MDPI, 2012-07-30)Bicycles are known to be rich source of kinetic energy, some of which is available for harvesting during speedy and balanced maneuvers by the user. A conventional dynamo attached to the rim can generate a large amount of output power at an expense of extra energy input from the user. However, when applying energy conversion technology to human powered equipments, it is important to minimize the increase in extra muscular activity and to maximize the efficiency of human movements. This study proposes a novel energy harvesting methodology that utilizes lateral oscillation of bicycle frame (weaving) caused by user weight shifting movements in order to increase the pedaling force in uphill riding or during quick speed-up. Based on the 3D motion analysis, we designed and implemented the prototype of an electro-dynamic energy harvester that can be mounted on the bicycle's handlebar to collect energy from the side-to-side movement. The harvester was found to generate substantial electric output power of 6.6 mW from normal road riding. It was able to generate power even during uphill riding which has never been shown with other approaches. Moreover, harvesting of energy from weaving motion seems to increase the economy of cycling by helping efficient usage of human power.
- Cytotoxicity and Cellular Uptake of Cellulose NanocrystalsDong, Shuping; Hirani, Anjali A.; Colacino, Katelyn R.; Lee, Yong Woo; Roman, Maren (2012-09-21)There is growing evidence that filamentous nanoparticles offer advantages over spherical ones in drug delivery applications. The purpose of this study was to assess the potential of rod-like, plant-derived cellulose nanocrystals (CNCs) for nanomedical uses. Besides a nonspherical morphology, their facile bioconjugation, surface hydrophilicity and small size render CNCs promising drug carriers. The cytotoxicity of CNCs against nine different cell lines (HBMEC, bEnd.3, RAW 264.7, MCF-10A, MDA-MB-231, MDA-MB-468, KB, PC-3 and C6) was determined by MTT and LDH assay. CNCs showed no cytotoxic effects against any of these cell lines in the concentration range and exposure time studied (0–50 µg/mL and 48 h, respectively). Cellular uptake of fluorescein-50 - isothiocyanate-labeled CNCs by these cell lines, quantified with a fluorescence microplate reader, was minimal. The lack of cytotoxicity and the low nonspecific cellular uptake support our hypothesis that CNCs are good candidates for nanomedical applications.
- Controlling Morphological Parameters of Anodized Titania Nanotubes for Optimized Solar Energy ApplicationsHaring, Andrew J.; Morris, Amanda J.; Hu, Michael (MDPI, 2012-10-19)Anodized TiO2 nanotubes have received much attention for their use in solar energy applications including water oxidation cells and hybrid solar cells [dye-sensitized solar cells (DSSCs) and bulk heterojuntion solar cells (BHJs)]. High surface area allows for increased dye-adsorption and photon absorption. Titania nanotubes grown by anodization of titanium in fluoride-containing electrolytes are aligned perpendicular to the substrate surface, reducing the electron diffusion path to the external circuit in solar cells. The nanotube morphology can be optimized for the various applications by adjusting the anodization parameters but the optimum crystallinity of the nanotube arrays remains to be realized. In addition to morphology and crystallinity, the method of device fabrication significantly affects photon and electron dynamics and its energy conversion efficiency. This paper provides the state-of-the-art knowledge to achieve experimental tailoring of morphological parameters including nanotube diameter, length, wall thickness, array surface smoothness, and annealing of nanotube arrays.
- Piezoelectric MEMS for energy harvestingKim, Sang-Gook; Priya, Shashank; Kanno, Isaku (Cambridge University Press, 2012-11)Piezoelectric microelectromechanical systems (MEMS) have been proven to be an attractive technology for harvesting small magnitudes of energy from ambient vibrations. This technology promises to eliminate the need for replacing chemical batteries or complex wiring in microsensors/microsystems, moving us closer toward battery-less autonomous sensors systems and networks. To achieve this goal, a fully assembled energy harvester the size of a US quarter dollar coin (diameter = 24.26 mm, thickness = 1.75 mm) should be able to robustly generate about 100 mu W of continuous power from ambient vibrations. In addition, the cost of the device should be sufficiently low for mass scale deployment. At the present time, most of the devices reported in the literature do not meet these requirements. This article reviews the current state of the art with respect to the key challenges such as high power density and wide bandwidth of operation. This article also describes improvements in piezoelectric materials and resonator structure design, which are believed to be the solutions to these challenges. Epitaxial growth and grain texturing of piezoelectric materials is being developed to achieve much higher energy conversion efficiency. For embedded medical systems, lead-free piezoelectric thin films are being developed, and MEMS processes for these new classes of materials are being investigated. Nonlinear resonating beams for wide bandwidth resonance are also being developed to enable more robust operation of energy harvesters.
- Sustainable Biomaterials Newsletter, v.8 (Fall 2013)(Department of Sustainable Biomaterials, 2013)
- Food Digest : 2013Virginia Tech. Food Science and Technology Department (Virginia Tech. Food Science and Technology Department, 2013)Message from the Department Head: Greetings. A lot has happened since our last newsletter. I hope as you take the time to read these stories, they will help you reconnect and remind you of the many friendships formed at Virginia Tech. Please take the time to update your contact information with the Department of Food Science and Technology or through the Alumni Association. We really do wish to keep in touch. Three years ago a survey was conducted with all of the IFT approved Food Science programs to see how many undergraduates were in the U.S. Out of 49 programs that responded at that time, Virginia Tech ranked 19th. Now we have greater than 130 undergraduate majors and are tied for seventh place for undergraduate program size. Our graduate program is also very strong; when we count the students in both residential and on-line degree programs, we have nearly 50 graduate students. As enrollment has increased, we’ve begun to outgrow our classroom. Many of you may still remember taking courses in FST 132; however our class sizes now exceed the room’s size, sending some classes to rooms across campus. The people of FST are also in transition. We celebrated with Harriet Williams, Walter Hartman, and Brian Smith as they all retired last summer. We miss them deeply, but their retirements were well earned. We see them often, looking healthy and enjoying extra time for their own interests. One of the biggest changes for me, personally, was the unexpected death of Cameron R. Hackney, Ph.D. Cameron and I were students together and shared many enjoyable hours during our professional careers. I admired his scholarly work, his amazing teaching ability, and his sincere care for others. He was my friend, and I miss him very much. Others, who were also touched by Cameron, have established an endowed fund in his honor. The proceeds from the Cameron R. Hackney Memorial Enrichment Fund will be used to cultivate the educational activities of undergraduate and graduate students in the FST Department. We welcome contributions to this fund from any who wish to honor Cameron. Best personal regards, Joe Marcy.
- Sustainable Biomaterials Newsletter, v.8 (Winter 2013)(Department of Sustainable Biomaterials, 2013)
- The CEHMS Chronicle, January 2013(Virginia Tech, 2013-01)This is the quarterly newsletter for the Center for Energy Harvesting Materials and Systems.