Conventional Vickers and true instrumented indentation hardness determined by instrumented indentation tests

We evaluate Vickers hardness and true instrumented indentation test (IIT) hardness of 24 metals over a wide range of mechanical properties using just IIT parameters by taking into account the real contact morphology beneath the Vickers indenter. Correlating the conventional Vickers hardness, indentation contact morphology, and IIT parameters for the 24 metals reveals relationships between contact depths and apparent material properties. We report the conventional Vickers and true IIT hardnesses measured only from IIT contact depths; these agree well with directly measured hardnesses within ±6% for Vickers hardness and ±10% for true IIT hardness

Enhancement on Radon Adsorption Property of GAC using Nano-size Carbon Colloids

Granular activated carbon (GAC) is well-known as an efficient adsorbent against a number of gaseous pollutants. Radon is one of those pollutants, and radon has been classified as the second leading cause of lung cancer in USA. This study was to enhance the radon removal efficiency with applying nano-technology. Nano-size carbon colloids (NCC) was produced through electrolysis which is simple and cheap. NCC was used for impregnation with activated carbon. Surface areas of both NCC-treated and non-treated activated carbon did not show a significant difference. However, the results of radon removal efficiency show that impregnated carbon with NCC could capture about 1.3 ~ 2 times of more radon gas compared to non-treated activated carbon. It is assumed that nano-size carbon colloids might have filled up meso-pores, and meso-pores turned into micro-pores eventually. Because meso-pores initially accounted for large portion of whole pores, more radon could be captured to NCC-impregnated activated carbon. Keywords: Radon, Nano-Size Carbon Collid, Activated Carbo

Current Developments in Thermochemical Conversion of Biomass to Fuels and Chemicals

Biomass is one of the largest concentrated carbon source available for producing renewable energy. Thermochemical conversion of biomass has been used for centuries in various settings. Biomass typically has a higher oxygen and volatile matter content than other solid carbon feedstocks, resulting in increased reactivity during conversion by thermochemical pathways. Moisture content of the biomass feedstock exerts significant influence on the conversion process and is an important criteria used to classify various thermochemical conversion technologies. This chapter discusses the current status and future outlook of thermochemical biomass conversion processes

Characteristics of the Aragonitic Layer in Adult Oyster Shells, Crassostrea gigas: Structural Study of Myostracum including the Adductor Muscle Scar

Myostracum, which is connected from the umbo to the edge of a scar, is not a single layer composed of prismatic layers, but a hierarchically complex multilayered shape composed of minerals and an organic matrix. Through the analysis of the secondary structure, the results revealed that a β-antiparallel structure was predominant in the mineral phase interface between the myostracum (aragonite) and bottom folia (calcite). After the complete decalcification and deproteinization, the membrane obtained from the interface between the myostracum buried in upper folia, and the bottom folia was identified as chitin. The transitional zone in the interface between the adductor muscle scar and folia are verified. The myostracum disappeared at the edge of the scar of the posterior side. From this study, the entire structure of the myostracum from the adult oyster shell of Crassostrea gigas could be proposed

Experimental study on the removal of sulfur compounds and siloxanes from biogas

Biogas is a renewable energy source, which can be produced by anaerobic digestion with anaerobic organisms from agriculture waste, manure, municipal waste, sewage, food waste, etc. The biogas consists primarily of methane and carbon dioxide, but also smaller amounts of nitrogen, oxygen, hydrogen and volatile organic compounds including sulfur compounds, halogenated compounds and organic silicon compounds may be present. Here, methane which is the main component in the biogas may be used as a fuel in many applications such as heating, combined heat and power systems, fuel cells, etc. For the implementation of methane, therefore, the biogas needs purification to improve its quality in most cases by removing impurities from the biogas, resulting in no corrosion and scaling problems in the applications. In the present work, a hybrid biogas purification process, consisting of a physicochemical process with an adsorption for the removal of sulfur compounds and siloxanes and a membrane separation process for the removal of carbon dioxide, has been proposed. The main focus of this study is to examine the physical properties and adsorption characteristics of adsorbents being used to remove sulfur compounds and siloxanes from the biogas. Indeed, recent studies are on the desulfurization and siloxane removal process using an activated carbon and impregnated activated carbon. However, there are many different types of sulfur compounds and siloxanes in the biogas and each may have a different reaction rate and adsorption capacity. In this study, therefore, several commercially-available adsorbents are selected to analyze their removal capacities for the main components (methane) and major impurities in the biogas. The main impurities considered in this work are hydrogen sulfide (H2S), carbonyl sulfide (COS), carbon disulfide (CS2), Octamethylcyclotetrasiloxane (D4) and Decamethylcyclopentasiloxane (D5), based on the measurements from the on-site sewage treatment plant in Incheon, Korea. In the bench-scale adsorption experiments, iron oxide, activated carbon, impregnated activated carbon and inorganic adsorbents such as zeolite and silica gel are used as adsorbents for the removal of impurities from synthetic biogas and their physical properties are analyzed with XRF, SEM and BET analyses. The experimental results show that the adsorption capacity of hydrogen sulfide in the iron oxide (IO) is superior to those of the activated carbon (AC) and impregnated activated carbon (IAC) with a relatively good adsorption capacity (Figure 1). In addition, the removal efficiency of carbonyl sulfide and carbon disulfide with the activated carbon is more effective than using the iron oxide having a very poor adsorption capacity (Figure 2). It is also shown that both activated carbon and zeolite exhibit a high adsorption capacity of siloxanes D4 and D5. Especially, in case of siloxane D5, the zeolite has a better adsorption capacity than the activated carbon (Figure 3). More detailed results will be presented at the conference. Please click Additional Files below to see the full abstract

The stability of graphene band structures against an external periodic perturbation; Na on Graphene

We report that the $\pi$ band of graphene sensitively changes as a function of an external potential induced by Na especially when the potential becomes periodic at low temperature. We have measured the band structures from the graphene layers formed on the 6H-SiC(0001) substrate using angle-resolved photoemission spectroscopy with synchrotron photons. With increasing Na dose, the $\pi$ band appears to be quickly diffused into background at 85 K whereas it becomes significantly enhanced its spectral intensity at room temperature (RT). A new parabolic band centered at $k\sim$1.15 \AA$^{-1}$ also forms near Fermi energy with Na at 85 K while no such a band observed at RT. Such changes in the band structure are found to be reversible with temperature. Analysis based on our first principles calculations suggests that the changes of the $\pi$ band of graphene be mainly driven by the Na-induced potential especially at low temperature where the potential becomes periodic due to the crystallized Na overlayer. The new parabolic band turns to be the $\pi$ band of the underlying buffer layer partially filled by the charge transfer from Na adatoms. The five orders of magnitude increased hopping rate of Na adatoms at RT preventing such a charge transfer explains the absence of the new band at RT.Comment: 6 pages and 6 figure

Biochemical characterization of a recombinant Japanese encephalitis virus RNA-dependent RNA polymerase

<p>Abstract</p> <p>Background</p> <p>Japanese encephalitis virus (JEV) NS5 is a viral nonstructural protein that carries both methyltransferase and RNA-dependent RNA polymerase (RdRp) domains. It is a key component of the viral RNA replicase complex that presumably includes other viral nonstructural and cellular proteins. The biochemical properties of JEV NS5 have not been characterized due to the lack of a robust <it>in vitro </it>RdRp assay system, and the molecular mechanisms for the initiation of RNA synthesis by JEV NS5 remain to be elucidated.</p> <p>Results</p> <p>To characterize the biochemical properties of JEV RdRp, we expressed in <it>Escherichia coli </it>and purified an enzymatically active full-length recombinant JEV NS5 protein with a hexahistidine tag at the N-terminus. The purified NS5 protein, but not the mutant NS5 protein with an Ala substitution at the first Asp of the RdRp-conserved GDD motif, exhibited template- and primer-dependent RNA synthesis activity using a poly(A) RNA template. The NS5 protein was able to use both plus- and minus-strand 3'-untranslated regions of the JEV genome as templates in the absence of a primer, with the latter RNA being a better template. Analysis of the RNA synthesis initiation site using the 3'-end 83 nucleotides of the JEV genome as a minimal RNA template revealed that the NS5 protein specifically initiates RNA synthesis from an internal site, U₈₁, at the two nucleotides upstream of the 3'-end of the template.</p> <p>Conclusion</p> <p>As a first step toward the understanding of the molecular mechanisms for JEV RNA replication and ultimately for the <it>in vitro </it>reconstitution of viral RNA replicase complex, we for the first time established an <it>in vitro </it>JEV RdRp assay system with a functional full-length recombinant JEV NS5 protein and characterized the mechanisms of RNA synthesis from nonviral and viral RNA templates. The full-length recombinant JEV NS5 will be useful for the elucidation of the structure-function relationship of this enzyme and for the development of anti-JEV agents.</p