鉄鋼スラグによる硫化物含有底質の改善効果に関する研究

広島大学(Hiroshima University)博士(学術)Doctor of Philosophydoctora

Alkali Elution Behavior of Steelmaking Slag Packed in an Open Channel Vessel in Seawater

The alkali elution behavior of steelmaking slag in seawater was kinetically investigated and simulated under continuous flow in an open channel vessel with packed bed of steelmaking slag. Two types of steelmaking slags, viz. decarburization slag and dephosphorization slag, were used in this study. The alkali elution rate of decarburization slag was larger than that of dephosphorization slag due to larger free CaO content. The pH value for dephosphorization slag was almost the same as the seawater pH value in 3–4 days, whereas that for decarburization slag was stabilized in 3 days although the pH value was slightly larger than that of seawater. The capacity coefficients of alkali elution for dephosphorization and decarburization slags decreased together in an exponential manner with time. Based on a regression equation on the mass transfer capacity coefficient change with time, the alkali elution behavior was simulated and the calculated results agreed well with the experimental ones. The temporal pH change was predicted by changing slag surface area and seawater flow rate as a parameter. According to the simulation results for dephosphorization slag, the seawater pH value did not reach a high level in the ocean area

Correct Use of a Conventional Lap-and-Shoulder Seatbelt Is Safest for Pregnant Rear-Seat Passengers : Proposal for Additional Safety Measures

The objectives of this study were to assess the safety of various methods of seatbelt use and propose safety improvements to the lap-and-shoulder seatbelt for pregnant rear-seat passengers. The Maternal Anthropometric Measurement Apparatus dummy, version 2B, was used. Sled tests were performed to simulate frontal impact at a speed of 48 km/h in the right rear seat. Kinematics of the dummy were examined using high-speed video imaging, and time courses of the seatbelt loads and displacement and acceleration of the chest and pelvis were measured during impact. The kinematic parameters were compared under the following conditions: conventional lap-and-shoulder seatbelt used correctly, lap belt crossed over left and right femurs, and lap belt attached to both thighs using an extra restraint device. Then, by applying pretensioner and/or force limiter systems, the safest condition was investigated. Correct conventional seatbelt use was the most effective restraint method. When both pretensioner and force limiter were applied, the kinematic parameters were smallest, and the best restraint was achieved. The safety of rear-seat travel can be improved by using both pretensioner and force limiter systems, which would reduce the risk of chest and abdominal injuries to pregnant passengers and prevent negative fetal outcomes

Factors Influencing Pregnant Women\u27s Injuries and Fetal Loss Due to Motor Vehicle Collisions: A National Crash Data-Based Study.

To examine the factors that influence substantial injuries for pregnant women and negative fetal outcomes in motor vehicle collisions (MVCs), a retrospective analysis using the National Automotive Sampling System/Crashworthiness Data System was performed in Shiga University of Medical Science. We analyzed data from 736 pregnant women who, between 2001 and 2015, had injuries that were an abbreviated injury scale (AIS) score of one or more. The mean age was 25.9 ± 6.4 years and the mean gestational age was 26.2 ± 8.2 weeks. Additionally, 568 pregnant women had mild injuries and 168 had moderate to severe injuries. Logistic regression analysis revealed that seatbelt use (odds ratio (OR), 0.30), airbag deployment (OR, 2.00), and changes in velocity (21-40 km/h: OR, 3.03; 41-60 km/h: OR, 13.47; ≥61 km/h: OR, 44.56) were identified as independent predictors of having a moderate to severe injury. The positive and negative outcome groups included 231 and 12 pregnant women, respectively. Injury severity in pregnant women was identified as an independent predictor of a negative outcome (OR, 2.79). Avoiding moderate to severe maternal injuries is a high priority for saving the fetus, and education on appropriate seatbelt use and limiting vehicle speed for pregnant women is required

Comparison of the Injury Mechanism between Pregnant and Non-Pregnant Women Vehicle Passengers Using Car Crash Test Dummies

This paper analyzes the kinematics and applied forces of pregnant and non-pregnant women dummies sitting in the rear seat during a frontal vehicle collision to determine differences in the features of abdominal injuries. Sled tests were conducted at 29 and 48 km/h with pregnant and non-pregnant dummies (i.e., MAMA IIB and Hybrid III). The overall kinematics of the dummy, resultant acceleration at the chest, transrational acceleration along each axis at the pelvis, and loads of the lap belt and shoulder belt were examined. The belt loads were higher for the MAMA IIB than for the Hybrid III because the MAMA IIB had a higher body mass than the Hybrid III. The differences in the lap belt loads were 1119 N at 29 km/h and 1981–2365 N at 48 km/h. Therefore, for restrained pregnant women sitting in the rear seat, stronger forces may apply to the lower abdomen during a high-velocity frontal collision. Our results suggest that for restrained pregnant women sitting in the rear seat, the severity of abdominal injuries and the risk of a negative fetal outcome depend on the collision velocity