Finite element analysis of knee injury risks in car-to-pedestrian impacts

In vehicle-pedestrian collisions, lower extremities of pedestrians are frequently injured by vehicle front structures. In this study, a finite element (FE) model of THUMS (total human model for safety) was modified in order to assess injuries to a pedestrian lower extremity. Dynamic impact responses of the knee joint of the FE model were validated on the basis of data from the literature. Since in real-world accidents, the vehicle bumper can impact the lower extremities in various situations, the relations between lower extremity injury risk and impact conditions, such as between impact location, angle, and impactor stiffness, were analyzed. The FE simulation demonstrated that the motion of the lower extremity may be classified into a contact effect of the impactor and an inertia effect from a thigh or leg. In the contact phase, the stress of the bone is high in the area contacted by the impactor, which can cause fracture. Thus, in this phase the impactor stiffness affects the fracture risk of bone. In the inertia phase, the behavior of the lower extremity depends on the impact locations and angles, and the knee ligament forces become high according to the lower extremity behavior. The force of the collateral ligament is high compared with other knee ligaments, due to knee valgus motions in vehicle-pedestrian collisions.     

Formation pathways of polychlorinated dibenzofurans (PCDFs) in sediments contaminated with PCBs during the thermal desorption process

Thermal desorption has attracted considerable interest as a remediation technology for the removal of dioxins and polychlorinated biphenyls (PCBs) from contaminated soils and sediments. Although several research groups have confirmed that polychlorinated dibenzofurans (PCDFs) are formed from PCBs during the thermal desorption of sediments contaminated with PCB, the formation pathways remain poorly understood. Herein, thermal desorption has been used to develop a greater understanding of the formation pathways of PCDFs from sediments contaminated with PCBs. PCB decomposition experiments of sediments contaminated with PCBs were performed over 5 min at 450 °C with a gas composition of 10% O(2)/90% N(2), either in the absence (Run 1) or presence (Run 2-4) of one of three different (13)C(12)-labeled PCB individual standards. The results of Run 1 showed that 99.96% of PCBs and 98.40% of polychlorinated dibenzo-p-dioxins (PCDDs) in the treated sediments had decomposed, whereas the concentration levels of PCDFs had increased by a factor of 31. The addition of different (13)C(12)-labeled PCBs to the sediment sample yielded different (13)C(12)-PCDFs isomer patterns, with formation pathways including loss of ortho-Cl(2), loss of HCl involving a 2,3-chlorine shift, loss of ortho-H(2) and dechlorination.     

Virtual phosphorus ore requirement of Japanese economy

Phosphorus is indispensable for agricultural production. Hence, the consumption of imported food indirectly implies the import of phosphorus resources. The global consumption of agricultural products depends on a small number of ore-producing countries. For sustainable management of phosphorus resources, the global supply and demand network should be clarified. In this study, we propose the virtual phosphorus ore requirement as a new indicator of the direct and indirect phosphorus requirements for our society. The virtual phosphorus ore requirement indicates the direct and indirect demands for phosphorus ore transformed into agricultural products and fertilizer. In this study, the virtual phosphorus ore requirement was evaluated for the Japanese economy in 2005. Importantly, the results show that our society requires twice as much phosphorus ore as the domestic demand for fertilizer production. The phosphorus contained in “eaten” agricultural products was only 12% of virtual phosphorus ore requirement.     

The Effects of the Level of Alertness During the Rest Period on Subsequent Performance

The aim of this study was to examine how to take an effective rest to prevent a decline in alertness at work. The relationship between alertness during the rest period and subsequent task performance were investigated. The electroencephalogram (EEG) during the rest period was classified into 3 types, and these types had a significant effect on performance after the rest period. Type 1 (increasing in theta, alpha 2, and beta 1 power) was the best one for carrying out the task, whereas performance gradually declined in Type 3 (no change in EEG activity). In the case of Type 1, the method that would relieve sleep inertia had a more positive impact on performance after the rest period.     

Nitrogen removal efficiencies and microbial communities in full-scale IFAS and MBBR municipal wastewater treatment plants at high COD:N ratio

• Two IFAS and two MBBR full-scale systems (high COD:N ratio 8:1) were characterized. • High specific surface area carriers grew and retained slow-growing nitrifiers. • High TN removal is related to high SRT and low DO concentration in anoxic tanks. The relative locations of AOB, NOB, and DNB were examined for three different kinds of carriers in two types of hybrid biofilm process configurations: integrated fixed-film activated sludge (IFAS) and moving bed biofilm reactor (MBBR) processes. IFAS water resource recovery facilities (WRRFs) used Anodkalness^TM K1 carriers (KC) at Broomfield, Colorado, USA and polypropylene resin carriers (RC) at Fukuoka, Japan, while MBBR WRRFs used KC carriers at South Adams County, Colorado, USA and sponge carriers (SC) at Saga, Japan. Influent COD to N ratios ranged from 8:1 to 15:1. The COD and BOD removal efficiencies were high (96%–98%); NH₄⁺-N and TN removal efficiencies were more varied at 72%–98% and 64%–77%, respectively. The extent of TN removal was higher at high SRT, high COD:N ratio and low DO concentration in the anoxic tank. In IFAS, RC with high specific surface area (SSA) maintained higher AOB population than KC. Sponge carriers with high SSA maintained higher overall bacteria population than KC in MBBR systems. However, the DNB were not more abundant in high SSA carriers. The diversity of AOB, NOB, and DNB was fairly similar in different carriers. Nitrosomonas sp. dominated over Nitrosospira sp. while denitrifying bacteria included Rhodobacter sp., Sulfuritalea sp., Rubrivivax sp., Paracoccus sp., and Pseudomonas sp. The results from this work suggest that high SRT, high COD:N ratio, low DO concentration in anoxic tanks, and carriers with greater surface area may be recommended for high COD, BOD and TN removal in WRRFs with IFAS and MBBR systems.