Evaluation of the Water Shielding Performance of a Capillary Barrier System through a Small-Scale Model Test

Capillary barrier (CB) systems consisting of a fine-grained soil layer placed over a coarse-grained soil layer can generally provide a water-shielding effect, increasing the slope stability of soil structures during rainfall. In order to improve the water-shielding performance of CB systems, laboratory model tests have been previously conducted under various conditions; notably, large-scale model tests are especially required. The inefficiency in increasing the production time of CB models until now explains their high cost. In this paper, we propose a laboratory small-scale CB (SSCB) model test for a quick and efficient evaluation of the function of a CB system. In this model test, differently from previous studies, a side drainage flow in the direction of the inclined sand layer was set as the no-flow condition; moreover, the laboratory SSCB model tests were performed by considering three rainfall intensities (i.e., 20, 50, and 100 mm/h) under the lateral no-flow condition. The results showed that the larger the rainfall intensity, the shorter the diversion length was of the CB system. To evaluate the effectiveness of the SSCB model test proposed in this study, the diversion length was estimated by an empirical equation under the lateral flow condition based on hydraulic conductivity functions and the soil water characteristic curves of sand and gravel and then compared to the results of the SSCB model tests. It was hence demonstrated that the water-shielding performance of the CB system can be efficiently evaluated through SSCB model tests under the lateral no-flow condition, rather than through large-scale model tests

Layer-by-Layer-Assembled Multilayer Films for Transcutaneous Drug and Vaccine Delivery

We describe protein- and oligonucleotide-loaded layer-by-layer (LbL)-assembled multilayer films incorporating a hydrolytically degradable polymer for transcutaneous drug or vaccine delivery. Films were constructed based on electrostatic interactions between a cationic poly(β-amino ester) (denoted Poly-1) with a model protein antigen, ovalbumin (ova), and/or immunostimulatory CpG (cytosine−phosphate diester−guanine-rich) DNA oligonucleotide adjuvant molecules. Linear growth of nanoscale Poly-1/ova bilayers was observed. Dried ova protein-loaded films rapidly deconstructed when rehydrated in saline solutions, releasing ova as nonaggregated/nondegraded protein, suggesting that the structure of biomolecules integrated into these multilayer films is preserved during release. Using confocal fluorescence microscopy and an in vivo murine ear skin model, we demonstrated delivery of ova from LbL films into barrier-disrupted skin, uptake of the protein by skin-resident antigen-presenting cells (Langerhans cells), and transport of the antigen to the skin-draining lymph nodes. Dual incorporation of ova and CpG oligonucleotides into the nanolayers of LbL films enabled dual release of the antigen and adjuvant with distinct kinetics for each component; ova was rapidly released, while CpG was released in a relatively sustained manner. Applied as skin patches, these films delivered ova and CpG to Langerhans cells in the skin. To our knowledge, this is the first demonstration of LbL films applied for the delivery of biomolecules into skin. This approach provides a new route for storage of vaccines and other immunotherapeutics in a solid-state thin film for subsequent delivery into the immunologically rich milieu of the skin.Massachusetts Institute of Technology. Institute for Soldier NanotechnologiesSingapore. Agency for Science, Technology and Researc

Journal of the Korean Society of Marine Engineering 672 / 한국마린엔지니어링학회지 제33권 제5호

Abstract：Acoustic Emission (AE) technique is a non-destructive testing method and widely used for the early detection of faults in rotating machines in these days, because the sensitivity of AE transducers is higher than normal accelerometers. So it can detect low energy vibration signals. The faults in the rotating machines are generally occurred at bearings and gearboxes which are the principal parts of the machines. It was studied to detect the bearing faults by envelop analysis in several decade years. And the researches showed that AE had a possibility of the application in condition monitoring system(CMS) using the envelope analysis for the rolling bearing. And peak ratio (PR) was developed for expression of the bearing condition in condition monitoring system using AE. Noise level is needed to reduce to take exact PR value because the PR is calculated from total root mean square (RMS) and the harmonics peak levels of the defect frequencies of the bearing. Therefore, in this paper, the discrete wavelet transform (DWT) was added in the envelope analysis to reduce the noise level in the AE signals. And then, the PR was calculated and compared with general envelope analysis result and the result of envelope analysis added the DWT. In the experiment result about inner fault of bearing, defect frequency was difficult to find about only envelop analysis. But it's easy to find defect frequency after wavelet transform. Therefore, Envelop analysis added wavelet transform was useful method for early detection of default in signal process. Key words：Acousti

Optical switching of the Dirac point in graphene multilayer field-effect transistors functionalized with spiropyran

A facile method for achieving optical switching of the Dirac point and conductance in reduced graphene oxide multilayer FETs that are non-covalently functionalized with a photoresponsive spiropyran derivative is presented. The photoresponsive transition from spiropyran to merocyanine induces the reversible optical switching in graphene based FETs.close6

Covalent functionalization based heteroatom doped graphene nanosheet as a metal-free electrocatalyst for oxygen reduction reaction

Oxygen reduction reaction (ORR) is an important reaction in energy conversion systems such as fuel cells and metal-air batteries. Carbon nanomaterials doped with heteroatoms are highly attractive materials for use as electrocatalysts by virtue of their excellent electrocatalytic activity, high conductivity, and large surface area. This study reports the synthesis of highly efficient electrocatalysts based on heteroatom-doped graphene nanosheets prepared through covalent functionalization using various small organic molecules and a subsequent thermal treatment. A series of nitrogen-doped reduced graphene oxide (NRGOn) nanosheets exhibited varying degrees and configurations of nitrogen atoms within the graphitic framework depending on the type of precursors used. On the basis of the rotating disk electrode (RDE) and rotating ring-disk electrode (RRDE) experiments, NRGO3, with a high degree of pyridinic-N content, displayed the desired one-step, quasi-four-electron transfer pathway during ORR, similar to commercial Pt/C. We also demonstrated the potential of covalent functionalization of sulfur and boron-doped graphene nanosheets.close4

Hydrogen-bonded multilayer of pH-responsive polymeric micelles with tannic acid for surface drug delivery

We report the design of a platform for the delivery of hydrophobic drugs conjugated to block copolymer micelles via pH-responsive linkage that are assembled within hydrogen-bonded polymer multilayer thin films.close465

Drug delivery by a self-assembled DNA tetrahedron for overcoming drug resistance in breast cancer cells

A DNA tetrahedron is employed for efficient delivery of doxorubicin into drug-resistant breast cancer cells. The drug delivered with the DNA nanoconstruct is considerably cytotoxic, whereas free doxorubicin is virtually non-cytotoxic for the drug-resistant cells. Thus, the DNA tetrahedron, made of the inherently natural and biocompatible material, can be a good candidate for the drug carrier to overcome MDR in cancer cells.close11