Thermal and Electrical Behaviors of Selected Geomaterials

Geomaterials can be often classified into two groups: virgin geomaterials such as soil and rock, and by-product materials such as mine tailings, coal fly/bottom ash, foundry sand, kiln dust, blast furnace/steel slag, reclaimed concrete and asphalt. Studies on these materials and their mixtures have been carried out extensively for geoengineering applications, including the characterization of mechanical properties such as the strength, compressibility, compactivity and permeability, as well as mineralogical and geochemical properties. The goal of this study is to investigate the thermal and electrical properties of selected geomaterials and their mixtures for enhancement of knowledge and engineering applications. The thesis consists of three parts as follows: The first part presents the electrical conductivity measured on compacted kaolin clay using a circular two-electrode cell in conjunction with a specially designed compaction apparatus, which has the advantage of reducing errors owing to sample handling. The experimental results are analyzed to observe the influencing factors on the soil electrical conductivity. The performance of existing analytical models for predicting the soil electrical conductivity is evaluated by calculating empirical constants in these models. The second part investigates the thermal and packing behaviors of mine tailings and tire crumbs mixtures in dry and wet states, which are important in engineering applications for utilizing recycled tire particles as lightweight fill materials with improved thermal insulation. The thermal and packing properties measurements of the mine tailings and tire crumbs mixtures with different mixing ratios are presented, which are then analyzed to establish the thermal properties relationships with respect to the mixing ratio of tire crumbs, porosity, bulk density, water content, compactive effort and tire crumbs size. The multiple linear regression analysis shows that the thermal conductivity of the dry and wet mixtures can be estimated using a general model consisting of the factors affecting the thermal conductivity. The third part evaluates the thermal conductivity, compressive strength, elastic modulus and temperature changes of compacted mine tailings and fly ash mixtures during the curing period as functions of the fly ash ratio, molding water content and compaction energy. The microporosity structure of the fly ash treated mine tailings is also examined

Guards and Culprits in the Endoplasmic Reticulum: Glucolipotoxicity and β-Cell Failure in Type II Diabetes

The endoplasmic reticulum (ER) is a cellular organelle responsible for multiple important cellular functions including the biosynthesis and folding of newly synthesized proteins destined for secretion, such as insulin. The ER participates in all branches of metabolism, linking nutrient sensing to cellular signaling. Many pathological and physiological factors perturb ER function and induce ER stress. ER stress triggers an adaptive signaling cascade, called the unfolded protein response (UPR), to relieve the stress. The failure of the UPR to resolve ER stress leads to pathological conditions such as β-cell dysfunction and death, and type II diabetes. However, much less is known about the fine details of the control and regulation of the ER response to hyperglycemia (glucotoxicity), hyperlipidemia (lipotoxicity), and the combination of both (glucolipotoxicity). This paper considers recent insights into how the response is regulated, which may provide clues into the mechanism of ER stress-mediated β-cell dysfunction and death during the progression of glucolipotoxicity-induced type II diabetes

Distribution and Conservation of Long-billed Plovers Charadrius placidus in Korea

AbstractThe Long-billed Plover Charadrius placidus of distribution was surveyed from 2002 to 2005, on rivers, streams and coasts of 38 areas within Korea. The Sum of highest numbers (sum of peak counts) of Long-billed Plovers at 24 sites was 198 individuals. Number of observed individuals during breeding period was 88 individuals, 129 individuals during the migration period, and 56 individuals during the wintering period. The Long-billed Plover breeds and migrates throughout Korea. They spend winter south of 37° latitude. Highest numbers (73 individuals) were observed at Daejeon. Therefore, streams and rivers of Korea are considered as an important habitat for the Long-billed Plover

Novel water filtration of saline water in the outermost layer of mangrove roots

The scarcity of fresh water is a global challenge faced at present. Several desalination methods have been suggested to secure fresh water from sea water. However, conventional methods suffer from technical limitations, such as high power consumption, expensive operating costs, and limited system durability. In this study, we examined the feasibility of using halophytes as a novel technology of desalinating high-concentration saline water for long periods. This study investigated the biophysical characteristics of sea water filtration in the roots of the mangrove Rhizophora stylosa from a plant hydrodynamic point of view. R. stylosa can grow even in saline water, and the salt level in its roots is regulated within a certain threshold value through filtration. The root possesses a hierarchical, triple layered pore structure in the epidermis, and most Na+ ions are filtered at the first sublayer of the outermost layer. The high blockage of Na+ ions is attributed to the high surface zeta potential of the first layer. The second layer, which is composed of macroporous structures, also facilitates Na+ ion filtration. This study provides insights into the mechanism underlying water filtration through halophyte roots and serves as a basis for the development of a novel bio-inspired desalination method.Creative Research Initiative (Diagnosis of Biofluid Flow Phenomena and Biomimic Research) of the Ministry of Science, ICT and Future Planning (MSIP) , National Research Foundation (NRF) of Korea , ICT R&D program of MSIP/IITP (Korea