Simulating hydraulic fracturing processes in laboratory-scale geological media using three-dimensional TOUGH-RBSN

In this context, recent developments in the coupled three-dimensional (3D) hydro-mechanical (HM) simulation tool TOUGH-RBSN are presented. This tool is used to model hydraulic fracture in geological media, as observed in laboratory-scale tests. The TOUGH-RBSN simulator is based on the effective linking of two numerical methods: TOUGH2, a finite volume method for simulating mass transport within a permeable medium; and a lattice model based on the rigid-body-spring network (RBSN) concept. The method relies on a Voronoi-based discretization technique that can represent fracture development within a permeable rock matrix. The simulator provides two-way coupling of HM processes, including fluid pressure-induced fracture and fracture-assisted flow. We first present the basic capabilities of the modeling approach using two example applications, i.e. permeability evolution under compression deformation, and analyses of a static fracturing simulation. Thereafter, the model is used to simulate laboratory tests of hydraulic fracturing in granite. In most respects, the simulation results meet expectations with respect to permeability evolution and fracturing patterns. It can be seen that the evolution of injection pressure associated with the simulated fracture developments is strongly affected by fluid viscosity.     

Particulate emission factors for mobile fossil fuel and biomass combustion sources

PM emission factors (EFs) for gasoline- and diesel-fueled vehicles and biomass combustion were measured in several recent studies. In the Gas/Diesel Split Study (GD-Split), PM_2.5 EFs for heavy-duty diesel vehicles (HDDV) ranged from 0.2 to ~ 2 g/mile and increased with vehicle age. EFs for HDDV estimated with the U.S. EPA MOBILE 6.2 and California Air Resources Board (ARB) EMFAC2007 models correlated well with measured values. PM_2.5 EFs measured for gasoline vehicles were ~ two orders of magnitude lower than those for HDDV and did not correlate with model estimates. In the Kansas City Study, PM_2.5 EFs for gasoline-powered vehicles (e.g., passenger cars and light trucks) were generally < 0.03 g/mile and were higher in winter than summer. EMFAC2007 reported higher PM_2.5 EFs than MOBILE 6.2 during winter, but not during summer, and neither model captured the variability of the measured EFs. Total PM EFs for heavy-duty diesel military vehicles ranged from 0.18 ± 0.03 and 1.20 ± 0.12 g/kg fuel, corresponding to 0.3 and 2 g/mile, respectively. These values are comparable to those of on-road HDDV. EFs for biomass burning measured during the Fire Laboratory at Missoula Experiment (FLAME) were compared with EFs from the ARB Emission Estimation System (EES) model. The highest PM_2.5 EFs (76.8 ± 37.5 g/kg) were measured for wet (> 50% moisture content) Ponderosa Pine needles. EFs were generally < 20 g/kg when moisture content was < 20%. The EES model agreed with measured EFs for fuels with low moisture content but underestimated measured EFs for fuel with moisture content > 40%. Average EFs for dry chamise, rice straw, and dry grass were within a factor of three of values adopted by ARB in California's San Joaquin Valley (SJV). Discrepancies between measured and modeled emission factors suggest that there may be important uncertainties in current PM_2.5 emission inventories.     

Reconnaissance report on geotechnical damage caused by a localized torrential downpour with emergency warning level in Kyushu,Japan

Kumamoto and Kogoshima prefectures are located in the southern Kyushu district of western Japan. In July 2020, a warm, humid air front triggered the delayed rains of the rainy season, resulting in torrential rains in many parts of Japan, especially in Kyushu. In particular, heavy downpours occurred in the southern Kyushu district on July 4th, causing severe damage to much of the infrastructure. Details could not be analyzed as usual because some branch office of local government were also damaged by floods. The spatial distribution of precipitation in the Kuma River basin, in the southern part of Kumamoto, was characterized by the uniformity of 400–500 mm on July 3rd and 4th. Finally, emergency warnings of torrential rain were issued for the southern Kumamoto and the northern Kagoshima Prefectures by Japan Meteorological Agency (JMA) at 4:50 a.m., July 4th, 2020. Then, the active rain front gradually shifted towards northern Kyushu. Again, torrential rain fell on northern Kyushu in the afternoon due to a stagnant rainy season front, and the JMA issued an emergency warning for a localized torrential downpour for parts of Fukuoka, Saga and Nagasaki prefectures at 4:30 pm. Gradually, the damage status involving geodisasters such as several types of slope failures, road subsidence, damage of the river levee was reported by local governments in each area where there had been emergency warnings.Based on the brief report of the pre-investigation team from the Kyushu branch of the Japan Geotechnical Society (JGS) in the first week after the disaster on July 4th, the geo-research teams investigated the following: 1) landslides; 2) damaged roads; 3) damaged river levees, and 4) any geotechnical infrastructures which were partially damaged and may be even more severely damaged by the next torrential rain. This reconnaissance report introduces the geological features in Kyushu, the analysis of precipitation distribution and geotechnical damages on the slope failures, road failures and river embankments based on reports obtained from July 4th to August 31st, 2020.     

Population,technological conversion,and optimal environmental policy

We consider an economy comprising two production sectors. A manufactured goods sector emits environmental pollutants during production. The other sector is an agricultural goods sector producing with constant returns to scale. It is used as numeraire. In our model, moreover, it is possible for the firms in the manufactured goods sector to select the production technology of intermediate goods out of two technologies: a “classical technology” with constant returns to scale or “modern technology” with increasing returns to scale. We explain the environmental Kuznets curve, which is described in many empirical studies of environmental economics, by using our theoretical model and show some relations between the technological conversion and the generating factor of the environmental Kuznets curve. Moreover, we consider a case in which a population can move freely between regions and in which this technological conversion affects the population distribution in the long run.     

Case study on father–child communication in Chinese urban apartment houses through active RFID technology

This paper used Active Radio Frequency Identification (Active RFID) technology to identify in which rooms fathers and their child tend to stay together and talk, and in which rooms they stay separately in seven one-child families living in Chinese urban apartment houses. The father was found to stay together with the child 0.5%–25% of the time when both father and child stayed at home. The use of the living room as the place in which the child stays with the father and talks was found to be highest (five out of seven families), followed by the dining room and the child's room. In over half of the cases when the child stays with the father in the living room or dining room and either of them talk, the child spoke over 1.6 times more than the father. However, in the child's room, the child always spoke less than the father, and the duration of the child's speech was less than 70% of that of the father. Findings showed that the instances in which child and father stay in different rooms fell into two groups. First, five of the seven subject fathers tended to stay in the living room, whereas the children stayed either in their room or in their parents' room to use the PC. Second, two fathers stayed in the studio or dining room to work, while their children stayed in the living room or their own rooms. For both groups, the duration of these periods of stay covered 30.0%–81.4% of the time during which both the father and child stayed at home.     

Evaluation of wear and tribological properties of coatings rubbing against copper

A new crossed-cylinders tribo-tester is proposed. This tribo-tester can decrease the tendency of the chatter vibration. The tribological properties of coatings against copper is evaluated with this tribo-tester. The wear rate of TiN, TiC and TiCN rubbing against copper is higher than the substrate high speed tool steel: SKH51 (JIS). The catalytic action of copper for oxidation of Ti-based coatings is a main reason of this high wear rate of TiN, TiC and TiCN rubbing against copper. The wear rate of CrN rubbing against copper is in a very low level because CrN shows the excellent oxidation resistance and Cr₂O₃ film formation decreases the wear loss of CrN coating.     

Dietary Marine-Derived Tocopherol has a Higher Biological Availability in Mice Relative to Alpha-Tocopherol

The biologic availability of two kinds of tocomonoenols, marine-derived tocopherol (MDT) and α-tocomonoenol, was investigated in ICR mice. Vitamin E-deficient ICR mice were fed MDT and α-tocomonoenol together with α-tocopherol, β-tocopherol, γ-tocopherol, and δ-tocopherol, and storage in liver, spleen, lung, and brain was quantified using reverse-phase high-performance liquid chromatography. The vitamin E relative biologic availability (VE-RBA) in liver was 100 for α-tocopherol, 26 ± 3 for β-tocopherol, 4 ± 2 for γ-tocopherol, not detected for δ-tocopherol, 49 ± 6 for MDT, and 30 ± 7 for α-tocomonoenol. The VE-RBA in brain was 100 for α-tocopherol, 5 ± 2 for β-tocopherol, not detected for γ-tocopherol and δ-tocopherol, 8 ± 1 for MDT, and 4 ± 1 for α-tocomonoenol. Tocopherols and tocomonoenols did not accumulate in the spleen or lung. MDT and α-tocomonoenol had high VE-RBA values. The VE-RBA value for MDT was much higher than that for β-tocopherol.     

Synthesis of Diphenyl Carbonate from Phenol and Carbon Dioxide in the Presence of Carbon Tetrachloride and Zinc Chloride

Diphenyl carbonate (DPC) was synthesized from phenol and dense phase CO₂ in the presence of CCl₄ and K₂CO₃ using different catalysts of ZnCl₂, ZnBr₂, Lewis acid ionic liquids including 1-butyl-3-methylimidazolium chloride (BMIMCl) and bromide (BMIMBr). It was found that K₂CO₃ was not required, ZnCl₂ and ZnBr₂ were similar in the catalytic performance, and the use of BMIMCl and BMIMBr was not effective for the production of DPC. For the reactions with ZnCl₂ in CCl₄, the effects of such reaction variables as temperature, CO₂ pressure, the amount of ZnCl₂, and the volume of CCl₄ were studied in detail. It was shown that the pressure was less influential while a larger amount of ZnCl₂, a smaller volume of CCl₄, and a low temperature of around 100°C were beneficial for the synthesis of DPC. On the basis of the results obtained, possible reaction mechanisms were discussed.     

A crucial role of O2 and O2 on mayenite structure for biomass tar steam reforming over Ni/Ca12Al14O33

Newly synthesized nickel calcium aluminum catalysts (Ni/Ca₁₂Al₁₄O₃₃) were tested in a fixed bed reactor for biomass tar steam reforming, toluene as tar destruction model compound. Four catalysts (Ni/Ca₁₂Al₁₄O₃₃) were prepared with Ni loading amount from 1, 3, 5 to 7 wt%, even 1% loading catalyst also showed excellent performance. Catalysts aged experiments in the absence (60 h on stream) and presence of H₂S were characterized by BET, X-ray diffraction (XRD), and Raman spectra. It was observed that Ni/Ca₁₂Al₁₄O₃₃ showed excellent sustainability against coke formation due to the “free oxygen” in the catalysts. It also exhibited higher H₂S-poisoning resistance property compared to the commercial catalysts Ni/Al₂O₃ (5%) and Ni/CaO_0.5/MgO_0.5. Raman spectra revealed that “free oxygen O₂⁻ and O₂²⁻” in the structure of the catalysts could be substituted by sulfur then protected Ni poisoning on some degree, but reactivation experiments by O₂ flowing showed that the sulfide Ni/Ca₁₂Al₁₄O₃₃ was difficult to completely restore, incorporation of sulfur in the structure only partly regain by O₂. The kinetic model proposes, as generally accepted, a first-order reaction for toluene with activation energy of 82.06 kJ mol⁻¹ was coincident with the literature data. The Ni/Ca₁₂Al₁₄O₃₃ catalyst was effective and relative cheap, which may be lead to reduction in the cost of hot gas cleaning process.     

Functionality of dialyzed soybean extract

The soybean extract that was dialyzed against distilled and deionized water and adjusted to pH 7.5 (dialyzed soybean extract; d-SE) gave a transparent liquid after heating. The heated d-SE had less beany flavor and formed a translucent gel by heating again with 0.2 M NaCl. Gelation occurred at a lower protein concentration with NaCl than that of the original soybean extract. The dynamic viscoelasticity showed that the translucent gel from the heated d-SE was melted and gelled by the repetition of heating and cooling, indicating reversible gelsol transition. Cryoprecipitation could be avoided by the heating of d-SE. A gel was formed at 30°C by incubation of d-SE with NaCl. These properties of soybean extract may offer new applications as a food ingredient.