Gas transport in partially-saturated sand packs

Understanding gas transport in porous media and its mechanism has broad applications in various research areas, such as carbon sequestration in deep saline aquifers and gas explorations in reservoir rocks. Gas transport is mainly controlled by pore space geometrical and morphological characteristics. In this study, we apply a physically-based model developed using concepts from percolation theory (PT) and the effective-medium approximation (EMA) to better understand diffusion and permeability of gas in packings of angular and rounded sand grains as well as glass beads. Two average sizes of grain i.e., 0.3 and 0.5 mm were used to pack sands in a column of 6 cm height and 4.9 cm diameter so that the total porosity of all packs was near 0.4. Water content, gas-filled porosity (also known as gas content), gas diffusion, and gas permeability were measured at different capillary pressures. The X-ray computed tomography method and the 3DMA-Rock software package were applied to determine the average pore coordination number z. Results showed that both saturation-dependent diffusion and permeability of gas showed almost linear behavior at higher gas-filled porosities, while deviated substantially from linear scaling at lower gas saturations. Comparing the theory with the diffusion and permeability experiments showed that the determined value of z ranged between 2.8 and 5.3, not greatly different from X-ray computed tomography results. The obtained results clearly indicate that the effect of the pore-throat size distribution on gas diffusion and permeability was minimal in these sand and glass bead packs

Prevention of growth arrest-induced cell death of vascular smooth muscle cells by a product of growth arrest-specific gene, gas6

AbstractWe have purified Gas6 as a growth-potentiating factor for vascular smooth muscle cells (VSMCs) [Nakano, T. et al. (1995) J. Biol. Chem. 270, 5702-57051. However, specific production of Gas6 in growth-arrested cells raises an intriguing question as to the physiological function of Gas6. In this study, we found that serum-starved VSMCs secreted some survival factors and depletion of the factors induced cell death of VSMCs. Finally, we demonstrated that cell death was prevented by the addition of Gas6, suggesting that one of the major biological activity of Gas6 is protection of growth-arrested VSMCs from death

Temperature effects on geotechnical properties of kaolin clay: Simultaneous measurements of consolidation characteristics, shear stiffness, and permeability using a modified oedometer

The increased worldwide use of shallow geothermal energy systems including ground source heat pumps (GSHPs) have given concerns of possible temperature effects on soil geotechnical properties. In this study, the effects of temperature on mechanical characteristics such as consolidation settlement, shear stiffness, and permeability of kaolin clay were investigated. A modified oedometer apparatus which allows the simultaneous measurements of consolidation settlement, shear wave velocity, and hydraulic conductivity was developed and used. Consolidation tests on preconsolidated kaolin samples (two sample sizes: ϕ 6 cm x H 10 cm and ϕ 6 cm x H 2 cm) were performed under sequentially increasing consolidation pressures at three different temperatures (5 °C, 15 °C, and 40 °C). Larger apparent preconsolidation pressure, Pac, was seen at higher temperature (40 °C) for both sample sizes, but only for samples having relatively high initial void ratios between 1.53 and 1.62. Relatively higher shear modulus as a function of void ratio was observed for samples at higher temperature, suggesting that changes in fabric structure (likely caused by enhanced inter-particle forces between clay particles at higher temperature) resulted in the increased shear stiffness and, thus, higher Pac at 40 °C. Oppositely, temperature effects on theManuscript received February 5, 2013. This work was partly funded by a grant from the Research Management Bureau, Saitama University, the grant-in-Aid for Scientific Research of Japan Society for the Promotion of Science (JSPS) (No.22860012), and a JSPS bilateral research project. This work was also partially supported by a CREST project, a research grant from the Japan Science and Technology Agency (JST).E. E. Mon is with Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura ku, Saitama, 338-8570, Japan. (phone/fax: (+81) 48-858-3116; e-mail: [email protected]).S. Hamamoto, is with Graduate School of Science and Engineering, and Institute for Environmental Science and Technology, Saitama University, 255 Shimo-okubo, Sakura ku, Saitama, 338-8570, Japan. (e-mail: [email protected])K. Kawamoto is with Graduate School of Science and Engineering, and Institute for Environmental Science and Technology, Saitama University, 255 Shimo-okubo, Sakura ku, Saitama, 338-8570, Japan. (e-mail: [email protected]).T. Komatsu is with Graduate School of Science and Engineering, and Institute for Environmental Science and Technology, Saitama University, 255 Shimo-okubo, Sakura ku, Saitama, 338-8570, Japan. (e-mail: [email protected]).P. Mødrup is with Department of Biotechnology, Chemistry, and Environmental Engineering, Aalborg University, 9000 Aalborg, Denmark. (e-mail: [email protected]). permeability of kaolin clay were not significant within the studied temperature range between 5 °C and 40 °C

Geotechnical Properties of Kanto Alluvial Soils based on Geochemical Survey

Chemical properties of pore water in soils have a great influence on interparticle bonding among clayey particles and, as a result, not only on their soil structure but also on their geotechnical properties. In this study, we analyzed ionic compositions in pore water extracted from alluvial soils deposited under different sedimentary environments in Kanto lowland area, Japan, and investigated the effect of the chemical compositions of pore water on the geotechnical properties such as compressibility and sensitivity. The following results were obtained: The ion concentrations of pore water measured by different extraction methods showed that the concentration of Na+ by the dilution method was higher than that by the centrifugation method, while the concentrations of Ca2+, Cl- and SO42- by the dilution method are significantly smaller than those by centrifugation method. The centrifugation method was recommended for evaluating geochemistry of the soils since the rotation speeds in the centrifugation method did not significantly affect the pore-water compositions. The geotechnical properties were highly related to the ion concentrations of pore water. Higher compression index and sensitivity were observed for the alluvial soils with higher monovalent/divalent ion ratio. In addition, more strong dependency of monovalent/divalent ion ratio on geotechnical properties was obtained for the alluvial soils with plasticity index larger than 30

Measurements and Modeling of Thermal Conductivity of Recycled Aggregates from Concrete, Clay Brick, and Their Mixtures with Autoclaved Aerated Concrete Grains

Cool road pavements contribute to mitigating urban heat islands. To evaluate the heat balance in paved surfaces and to select appropriate road construction materials that help suppress heat islands, an accurate understanding of heat transport parameters such as thermal conductivity (λ) and heat capacity (HC) is important. Recycled aggregates from construction and demolition waste, including scrap construction materials and industrial by-products, are often used for road construction; however, λ and HC of recycled aggregates especially for roadbeds are not fully understood. This study involved a series of laboratory tests to measure λ and HC of recycled concrete and clay brick aggregates (λ and HC increased with increasing volumetric water content (θ). Closed-form models for estimating λ(θ) were proposed using normalized thermal conductivity (λe) and effective saturation (Se). The new λe(Se) models performed well for the measured data compared to previously proposed models and would be useful to evaluate λ of recycled aggregates for roadbed materials

Gas Diffusivity and Thermal Properties of Compost-mixed Soils under Variable Water Saturation

Gas and heat transport through compostmixed landfill cover soils affect the emission of toxic gases and methane oxidization processes. In this study, we mixed soils with three different composts in the ratio of either 1:5 or 1:10 (compost:soil) to understand the effect of compost mixing for gas diffusivity and thermal properties. The gas diffusion coefficient (Dp), thermal conductivity ( ), and heat capacity (HC) were measured for soils, composts, and compost-mixed soils at different soil-water matric potentials ( ) starting from nearly saturated to = -10,000 cm H2O and dry conditions. Data were fitted to the Brooks-Corey soil-water retention curve model to estimate the bubbling pressure ( b). For all materials, Dp increased linearly with increased air content ( ), and the Penman-Call linear Dp( ) model with the model slope (C) and threshold soil-air content ( th) fitted the data well. The th values increased with increasing compost content, relating non-linearly to the Brooks-Corey b but highly linearly to the soil macroporosity. Analogous to the Dp( ) model, Penman-Call type linear ( ), and HC( ) models with slopes (C′ and C′′) and intercepts ( 0 and HC0, thermal conductivity and heat capacity at a volumetric water content of = 0) captured reasonably well the data measured from dry to wet conditions. The C′ for varied depending on the compost ratio and decreased with increasing compost ratio. The C′′ for HC, on the other hand, had less effect on the compost mix. The thermal properties under the dry condition, 0 and HC0, were well correlated to the volumetric solid content. The results from this study will be helpful towards designing compost-mixed landfill cover soils with optimal heat and gas transport characteristics

The Comparison of the Dairy Farming by Jersey and Holstein-Friesian in Hiruzen District, Okayama Prefecture

現在,わが国の酪農経営に拾いて飼養されている乳牛は,その殆どがホルスタイン種で占められている. 確かにホルスタイン種は,良質な飼料条件のもとで高能力を発揮し,特に乳量に関しては明らかに他の品種に秀でるものがある. しかし,適地適品種の考えに立ちかえればホルスタイン種による酪農だけでは,効率のよい酪農経営が展開されるとは思われない. そこで本研究は,主に岡山県蒜山地区において展開されているジャージー酪農の経営調査の中から得られた結果をもとに,わが国酪農におけるジャージー種による酪農の成立条件を追求していくことを目的として行なわれた. 調査農家は,成牛30頭以上の専業経営に限定して選定された. 又,ジャージー種による酪農経営とホルスタイン種による酪農経営を比較するために,主にジャージー種を飼養している農家4戸,ジャージー種とホルスタイン種をほぼ半数ずつ飼養している農家2戸,ホルスタイン種を飼養している農家4戸の計10戸を選定した. 粗収益では農家1戸当り平均でみると,ホルスタイン農家がジャージー農家よりも422万円余り上回っていた. この差は,ホルスタイン種とジャージー種の乳量の格差による牛乳収入の違いと廃牛価格の違いによるものと考えられる. 逆に生産費用では農家1戸当り平均でみると,ジャージー農家がホルスタイン農家よりも466万円余り安価になっていた. この結果は,ジャージー種の濃厚飼料給与量がホルスタイン種に比べて約1,000㎏余り少ないことにより,ジャージー農家の購入飼料費が削減されたことによるものであった. 所得では農家1戸当り平均でみるとジャージー農家とホルスタイン農家は,ほぼ似通った成績を示した. 以上のことから,日本においてもジャージー種による酪農経営は,ホルスタイン種による酪農経営と対等に運営されることが実証された. 又,TDN自給率に関しては,ジャージー農家とホルスタイン農家では1戸当り平均,それぞれ,54.3,32.3%となって明らかにジャージー農家で高い値を示している. このことは,蒜山地区において土地利用性の点でジャージー種による酪農が,ホルスタイン種による酪農よりも優れていることを意味している｡ 以上のことから,今後の日本の酪農は,適地適品種の考えに則った上で展開されることが望ましい. そうすることにより,日本の穀物の自給率は高められて自活された酪農が展開されていくものと思われる

The role of Kyoto classification in the diagnosis of Helicobacter pylori infection and histologic gastritis among young subjects in Japan

　BACKGROUND AND AIM: Helicobacter pylori (H. pylori) infection induces inflammation of the gastric mucosa and leads to erosions, gastro-duodenal mucosa atrophy, and intestinal metaplasia. The Kyoto classification diagnoses H. pylori infection via endoscopic findings. We aimed to clarify the role of the Kyoto classification in diagnosing H. pylori infection and histologic gastritis in young Japanese individuals.　METHODS: From1031 consecutive subjects aged ≤29 years who underwent esophagogastroduodenal endoscopy at our two hospitals from 2010 to 2017, 220 were selected for participation in the present study. Endoscopic biopsy specimens from the antrum and corpus were used to investigate H. pylori infection and histology. Endoscopic and histological interpretations were based on the Kyoto classification and updated Sydney System. H. pylori infection was confirmed by histology and Giemsa or Gimenez staining.　RESULTS: Endoscopic findings were normal in 103 cases. Atrophy was found in 56 cases; diffuse redness, in 45 cases; nodularity, in 38 cases; and mucosal swelling, in 34 cases. The infection rate was 30.9% (68/220). In total, 67 subjects with H. pylori -positive endoscopic findings and confirmed as H. pylori -positive had histologic gastritis of the antrum and corpus. In contrast, of 153 subjects with H. pylori -negative endoscopic findings only 1 was subsequently confirmed to be H. pylori positive. Among the 67 subjects with H. pylori -positive endoscopic findings, 23 (34.3%) presented with histological atrophic gastritis of the corpus and 6 (9.0%) with intestinal metaplasia.　CONCLUSIONS: Our findings show that H. pylori infection is strongly associated with endoscopic and histologic gastritis in young subjects and both H. pylori infection and histologic gastritis can be evaluated endoscopically based on the Kyoto classification. Furthermore, prompt H. pylori eradication may prevent gastric cancer development given the high prevalence of atrophic gastritis and intestinal metaplasia in young Japanese individuals

Efficacy and safety of temporary biliary stent for prevention of post-ERCP cholangitis after endoscopic common bile duct stone removal: a retrospective study

　Although post-endoscopic retrograde cholangiopancreatography (ERCP) cholangitis (PEC) is not as severe as post-ERCP pancreatitis, this complication should not be disregarded. The aim of the present study was to evaluate the efficacy of a temporary biliary stent for prevention of PEC. Between April 2011 and May 2017, 190 patients underwent complete stone removal in a first session of ERCP at our hospital. Using propensity score matching, 72 pairs were enrolled in this study. After common bile duct (CBD) stone removal, the endoscopists decided to insert a temporary biliary stent if necessary. The incident rate of PEC was significantly lower in the stent group than the no-stent group (1% vs. 11%, p = 0.03). The length of hospital stay was also significantly shorter in the stent group than the no-stent group (5 days vs. 7 days, p < 0.01). In the stent group, one case had stent migration into the bile duct and two cases had a mooring stent at the papilla after 1 month. Multivariate analysis identified the pancreatic guide wire technique as a risk factor for PEC. We demonstrated that a temporary biliary stent reduced the incidence of PEC significantly and the outcome of its placement contributed to shortening the hospital stay. Furthermore, the placement of a temporary biliary stent caused fewer adverse effects than expected. Mooring stents were noted in three cases, which were confirmed by plain abdominal X-ray, but the patients had no symptoms. In two cases, the stent remained in the orifice of the papilla, and in one case it migrated into the CBD. All three stents were retrieved by elective endoscopic procedures. In conclusion, a temporary biliary stent can reduce the incidence of PEC and shorten the length of hospital stay without severe adverse outcomes