Smart Building and Construction Materials

Advances and innovations in materials science and engineering have always played a substantial role in civil engineering, building structural design, and construction. In recent years, extensive effort has been devoted to the applications of stimuli-responsive smart materials and nanostructures in buildings. These smart materials used in the built environment can be defined as those offering specific functional and adaptable properties in response to thermal, optical, structural, and environmental stimuli. Not only do these materials enhance the overall performance of new building construction but also promise safer structures, longer durability of building elements, efficient building energy savings, greater environmental sustainability, and even higher indoor user comfort. Given the increasing imperatives for the above, we have organized this themed special issue that focuses on smart buildings and construction materials. The main aim of this special issue is to encapsulate the current interest and state of research related to the smart materials in building and construction applications, underpinning current and future challenges in building energy, environmental sustainability, and structural safety and durability. In this special issue, after rigorous peer-review processes, the original research papers and review papers accepted cover a wide range of topics that address the critical issues in the development and implementation of smart materials for building design and construction. A total of ten papers in this special issue are listed

Optical thermal insulation via solar-energy harvesting photothermal nano coatings

The current technological advancement has enabled glass-based building facades with double- or triple-glazed transparent panels. However, the conventional glazing technologies cannot effectively reduce building thermal energy loss especially for large area transparent building skin. According to a report by the U.S. Department of Energy, building heating, ventilation, and air conditioning (HVAC) accounted for 14.0 % of primary energy consumption in the United States. Heat loss through windows in cold weather consumes about 3.9 quads, which is estimated to encompass 28.7 % of total HVAC energy consumption. [1] We have developed a novel concept of Optical Thermal Insulation (OTI) without any intervening medium (Fig. 1). Instead of applying a thermal insulator, a transparent photothermal (PT) film can selectively absorb photons near the UV and NIR regions and efficiently convert them to heat, therefore raising the window surface temperature (via free energy). As the inner surface temperature is raised relative to room temperature, the heat transfer at the window inner surface can be effectively reduced via the so-called OTI, especially in winter. It must be noted that the PT films are spectral selective with high absorptions near UV and IR, while allowing high visible transmittance, therefore transparent and ideal for façade engineering. Based on this concept, a so-called “Green Window” has been designed for single-pane applications that meet the U-factor specifications of Department of Energy for colder regions of the United Sates. The “Green Window” is composed of chlorophyll (Chl) retrieved from natural greens (by which the name “Green Window” is derived). [2] A thin film window coating of naturally occurring chlorophyll exhibits strong near UV and NIR absorptions and pronounced photothermal effect, while remaining highly transparent (Fig. 2). Upon collecting solar light, considerable heat is created, effectively raising the window surface temperature, leading to a reduced U-factor less than 1.7 W m-2 K-1, even below the values of double-panes. Based on these experimental results, we demonstrate of a new concept of “optical thermal insulation” that lifts the dependence on insulating materials making single-pane window highly possible. Fig. 2 shows the change in temperature (ΔTg) induced by simulated solar light as a function of time for the multilayer samples of chlorophyll. Consistently, thicker films (each layer is ~ 2 mm) gave greater ΔTg as expected. Conversely, the thicker films exhibit lower visible transmittance (VT). As shown in this figure, the temperature plateaus can be observed after 2 min.-irradiation by solar simulator. Fig. 2b shows ΔTg,max vs. VT for thin films of different layers (a maximum of 6 layers). ΔTg,max vs. VT displays a linear relationship extending to the point where no Chl film was applied (highest VT). Please click Additional Files below to see the full abstract

Deposition of YBCO thin films on silver substrate via a fluorine-free sol-gel synthesis

To further develop grain-textured YBCO thin films for conductor development, we deposited, via a fluorine-free sol-gel synthesis, YBCO thin films on non-textured silver substrate. The interface structures were studied by both x-ray diffraction (XRD) and transmission electron microscopy (HRTEM). XRD data indicated that the YBCO films on silver substrate exhibited c-axis grain orientations. Experimental details are reported on the sol-gel synthesis chemistry and XRD and HRTEM characterization of the YBCO thin films. © 2002 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87877/2/654_1.pd

Linker Design Impacts Antibody-Drug Conjugate Pharmacokinetics and Efficacy via Modulating the Stability and Payload Release Efficiency

The development of antibody-drug conjugates (ADCs) has significantly been advanced in the past decade given the improvement of payloads, linkers and conjugation methods. In particular, linker design plays a critical role in modulating ADC stability in the systemic circulation and payload release efficiency in the tumors, which thus affects ADC pharmacokinetic (PK), efficacy and toxicity profiles. Previously, we have investigated key linker parameters such as conjugation chemistry (e.g., maleimide vs. disulfide), linker length and linker steric hindrance and their impacts on PK and efficacy profiles. Herein, we discuss our perspectives on development of integrated strategies for linker design to achieve a balance between ADC stability and payload release efficiency for desired efficacy in antigen-expressing xenograft models. The strategies have been successfully applied to the design of site-specific THIOMABTM antibody-drug conjugates (TDCs) with different payloads. We also propose to conduct dose fractionation studies to gain guidance for optimal dosing regimens of ADCs in pre-clinical models

Functionalization of single-walled carbon nanotubes using isotropic plasma treatment: Resonant Raman spectroscopy study

Functionalization of single-walled carbon nanotubes sSWNTsd by isotropic plasma treatment was studied using resonant Raman spectroscopy. It was shown that plasma-induced functionalization results in the uniaxial isotropic constriction of the nanotubes but preserves their overall structural integrity. It was demonstrated that NH3 ·H2O and hexamethyldisiloxan plasmas yield various types of conductivity for semiconducting SWNTs

Functionalization of single-walled carbon nanotubes using isotropic plasma treatment: Resonant Raman spectroscopy study

Functionalization of single-walled carbon nanotubes sSWNTsd by isotropic plasma treatment was studied using resonant Raman spectroscopy. It was shown that plasma-induced functionalization results in the uniaxial isotropic constriction of the nanotubes but preserves their overall structural integrity. It was demonstrated that NH3 ·H2O and hexamethyldisiloxan plasmas yield various types of conductivity for semiconducting SWNTs

Magnetic Relaxation And Intrinsic Pinning In A Single Crystal Of Bi2sr2cacu2ox

Magnetic-relaxation experiments were performed on Bi2Sr2CaCu2Ox single crystals with the direction of the field parallel to the ab plane. Based on the relaxation data, we have obtained relationships between the activation energy U and the current density j by an approach we developed previously. We found that the activation energy has a logarithmic dependence on j in a wide regime of driving force. It has been reported that CuO2 planes in high-Tc superconductors can act as strong intrinsic pinning centers and that the relation U∼U0ln(jc/j) may describe such a pinning mechanism. Our experimental results have shown good agreement with such a physical model of intrinsic flux pinning. © 1993 The American Physical Society.4795414541

Luminescent hydroxylapatite nanoparticles by surface functionalization

Hydroxylapatite (HA) nanoparticles were functionalized by depositing rare-earth-doped Y2O3Y2O3 nanoparticles on the surface, and the structural evolutions of both HA and Y2O3Y2O3 phases at different annealing temperatures were investigated by x-ray diffraction and transmission electron microscopy. Laser spectroscopy indicated that the surface functionalized HA nanoparticles exhibited strong visible emissions. No visible emissions were observed from rare-earth-doped Y2O3Y2O3 without any substrate, suggesting a doping-induced environmental change of optically active rare-earth elements in the functionalized HA nanoparticles. The luminescent hydroxylapatite nanoparticles may find important applications as a biodegradable substrate for biomarking and drug delivery.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87791/2/183106_1.pd

Tissue distribution and elimination of C-14 apixaban in rats

Abbreviations used: AUC, area under the plasma concentration-time curve; BCRP, breast cancer resistance protein; BLQ, below limit of quantitation; LSC, liquid scintillation counting; LC/MS, liquid chromatography/mass spectrometry; MS/MS, tandem mass spectrometry; Mrp, multidrug resistance protein; LLOQ, low limit of quantitation; P-gp, Pglycoprotein; PK, pharmacokinetics; QWBA, Whole-body autoradiography; SD, SpragueDawley rats. ABSTRACT Apixaban, a potent and highly selective factor Xa inhibitor, is currently under development for treatment of arterial and venous thrombotic diseases. The distribution, metabolism, and elimination of C-14 apixaban were investigated in male, female, pregnant and lactating rats following single oral doses. Tissue distribution of radioactivity in rats was measured using quantitative whole-body autoradiography. Following single oral administration, radioactivity distributed quickly in rats with C max at 1 h for most tissues. The elimination t 1/2 of radioactivity in blood was 1.7 to 4.2 h. The blood AUC of radioactivity was similar between male and female rats and was slightly higher in pregnant and lower in lactating rats. The radioactivity concentration in tissues involved in elimination was greater than blood with the highest concentration in gastrointestinal tracts, liver, urinary bladder/contents, and lowest level in brains. In pregnant rats, the whole-body autoradiogram showed that low levels of radioactivity were present in fetal blood, liver, and kidney, and were much lower than the radioactivity in respective maternal organs. Fecal route was the major (74% of dose) and urinary was minor pathway (14%) for apixaban elimination. Following single oral doses of C-14 apixaban to lactating rats, apixaban exhibited extensive lacteal excretion with apixaban as the major component. In summary, tissue distribution of apixaban in rats was extensive, but with limited transfer to fetal and brain tissues and extensive secretion into rat milk with parent drug as the major component. Milk excretion could account for 10% of apixaban dose, which was comparable to urinary elimination in rats. Tissue distribution and drug excretion of apixaban are consistent with a moderately permeable drug that is a substrate for P-gp and BCRP efflux transporters