Evaporation characteristics of multi-component liquid

Evaporation rate of multi-component liquid such as motor gasoline is expected to change greatly with progress of evaporation because its composition changes. Therefore it is difficult to predict accurately amount of generated combustible vapor in the case that a multi-component liquid is spilt on a floor. Then, we assumed an evaporation model that composition of the vapor obeys the Raoult's law which considers the activity coefficient. Using the model, we calculated the vapor composition, the vapor pressure and the evaporation rate of the liquid. Then, comparison was done between the calculated values and the measured values obtained in this study. “Weight loss fraction” was used as a parameter signifying the progress of evaporation. The variations of the evaporation property were accurately predicted by the model. We derived a prediction model of the amount of generated combustible vapor from the relation between weight loss fraction and evaporation rate. It was found that the amount of generated vapor was expressed as a logarithmic function of time in case of a five-component liquid. Furthermore, we showed that the predicted flash point of a liquid using the composition obtained from the model was in good agreement with an experimental result.     

The relationship of the monoterpene composition in the atmosphere,the foliar emission gas and the leaf oil of Pinus densiflora

Monoterpene compositions in the atmosphre in a pine forest, the foliar emission gas and the leaf oil of pine needles were compared. The emission rate of each monoterpene from pine needles was proportional to the product of the amount in the leaf oil and the approximate vapor pressure. The composition of monoterpenes in the atmosphere is rather well explained by considering foliar emission rates with the supposition that the terpenes emitted into the atmosphere react with ozone and photochemically with nitrogen oxides.     

Influence of velocity field on driftwood accumulation at a bridge with a single pier

Environmental Fluid Mechanics - Transport of driftwood during heavy rainfall events can intensify the flood hazard. Driftwood accumulates at a bridge and backwater rises. Accumulated logs sink...     

Is a hands-free phone safer than a handheld phone?

Introduction

Although it is becoming more and more accepted that driving while talking on a cell phone can be hazardous, most jurisdictions are making handheld phone use illegal while allowing hands-free phone use.

Methods

The scientific literature exploring the effects of these two types of cell phone use on driving and driving-related performance is reviewed here.

Results

Our review shows that talking on the phone, regardless of phone type, has negative impacts on performance especially in detecting and identifying events. Performance while using a hands-free phone was rarely found to be better than when using a handheld phone. Some studies found that drivers compensate for the deleterious effects of cell phone use when using a handheld phone but neglect to do so when using a hands-free phone.

Impact on Industry

Current research does not support the decision to allow hands-free phone use while driving.     

Accumulation features and temporal trends of PCDDs, PCDFs and PCBs in Baikal seals (Pusa sibirica)

This study investigated the accumulation features and temporal trends of PCDD/Fs, dioxin-like PCBs (DL-PCBs) and non-dioxin-like PCBs (NDL-PCBs) in the blubber of Baikal seals collected in 1992 and 2005. DL-PCBs (480-3600 ng/g) and NDL-PCBs (980-35,000 ng/g) were dominant contaminants. Concentrations of PCDDs and PCBs in males were significantly higher than in females. In males, age-dependent accumulation was observed for PCDDs, mono-ortho PCBs and NDL-PCBs. PCDFs and non-ortho PCBs showed no such trends, implying that exposure of seals to these contaminants has been decreasing in recent years. No decreasing temporal trend was observed for PCDDs, mono-ortho PCBs and NDL-PCBs, suggesting that Baikal seals are still exposed to PCDDs and PCBs. TEQs of PCDDs and mono-ortho PCBs in seals collected in 2005 accounted for 62-77% of total TEQs. The TEQ levels in 40% of the specimens exceeded the threshold level for immunosuppression observed in harbor seals (209 pg/g).     

Impact of conditions of cultivation and adsorption on antimicrobial activity of marine bacteria

The potency of free-living and animal-associated marine bacteria to produce antimicrobial substances has been studied in 491 strains isolated from northern and southern parts of the Pacific Ocean. A total of 26% (126 out of 491) of the strains examined produced antimicrobial compounds against 11 test bacterial strains (TBS) including the fish pathogens Aeromonas hydrophila and Vibrio anquillarum. Antimicrobial substances (AS) produced by marine bacteria were especially active against Staphylococcus epidermidis, Proteus vulgaris, Enterococcus faecalis, and Candida albicans. Twelve strains, isolated from different sources, were chosen as promising candidates, producing a number of AS. Production of AS varied within 24 to 72 h, increasing in a culture medium based on natural sea water with Br-ions, and after attachment to polymeric surfaces. In order to study the influence of adsorption, selected strains with a high potential for antimicrobial production were cultivated on polymeric surfaces with different hydrophobicities and chemical functionalities. These parameters of the surface hydrophobicity (measured by means of water contact angles) and chemical functionality of the surfaces were manipulated using the photo- and thermochemistry of a polymeric system (diazo-naphto-quinone/novolak) commonly used as a photoresistant material in semiconducto-manufacturing. The highest antimicrobial activities occurred on hydrophilic surfaces (standard exposed photoresistant films), whereas the number of attached cells was greater on hydrophobic surfaces, characterized as unexposed resistant films. These results suggest that the chemical nature of induced hydrophilicity may also be a major factor in controlling antimicrobial activity of adsorbed bacteria. Received: 5 March 1997 / Accepted: 24 August 1997     

Nationwide study of dioxins in the freshwater fish Carassius auratus (gibelio) langsdorfii (crucian carp) in Japan: concentrations and estimation of source contribution ratios

We investigated dioxin concentrations in freshwater fish in Japan by standardizing species to detect subtle decreasing trends of dioxin concentrations in the future with the reinforcement of regulations. The fish studied were crucian carp (Carassius auratus (gibelio) langsdorfii), an omnivorous species. Fish and sediments were collected from 14 rivers and lakes located in remote areas, agricultural areas, and small and large cities throughout Japan. The total toxic equivalent (TEQ) dioxin concentrations at the three remote sites were about 20% of the concentrations at the other 11 sites, which all had similar concentrations. The average concentrations in fish collected from these 11 sites were 0.69pgTEQg(-1) wet wt. (95% CI 0.52-0.85) or 57.3pgTEQg(-1) fat (95% CI 47.9-66.7). There were notable differences in congener profiles of polychlorinated p-dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) between sampling areas. A chemical mass balance method was used to estimate the proportions of dioxin contributions from different sources. The sampling areas were classified into four groups on the basis of the predominant source of dioxin contamination: a combustion group, a chlornitrofen herbicide group, a chlornitrofen and pentachlorphenol herbicide group, and a remote group. The congener profiles of dioxin like polychlorinated biphenyls (DL-PCBs) were almost the same in all areas and close to those in Kanechlor, which indicates that pollution from PCB products has spread throughout Japan. From samples collected during the spawning season, it was determined that about 20% of the dioxins in adult females were transferred to the eggs, resulting in higher dioxin concentrations in adult males than in females. Biota-sediment accumulation factors (BSAFs) of 2,3,7,8-substituted PCDDs/DFs for crucian carp were larger than those of non-2,3,7,8-substituted congeners, and BASFs decreased with increasing number of chlorines. The BSAFs of DL-PCBs were 10 times greater than those of PCDDs/DFs, and BSAFs of mono-ortho type DL-PCBs were higher than those of non-ortho types.     

Neonatal outcomes of congenital diaphragmatic hernia in full term versus early term deliveries: A systematic review and meta-analysis

This systematic review and meta-analysis aimed to review the optimal timing of delivery at term for neonates with prenatally diagnosed congenital diaphragmatic hernia (CDH). We reviewed the literature up to December 19, 2022 using MEDLINE and the Cochrane Library databases. The inclusion criteria were original articles, comparative studies of CDH neonates delivered at an early term (37–38 weeks of gestation) and at full term (39 weeks of gestation or later), and comparative studies investigating outcomes of CDH neonates. Six studies met the inclusion criteria, including 985 neonates delivered at an early term and 629 delivered at full term. The cumulative rate of survival to discharge showed no significant difference between CDH neonates delivered at an early term (395/515; 76.7%) or at full term (345/467; 73.9%) (risk ratio [RR] 1.01; 95% confidence interval [CI], 0.89–1.16; p = 0.85). Furthermore, the number of neonates requiring oxygen therapy at discharge was not significantly different between CDH neonates delivered at an early term (32/370; 8.6%) and at full term (14/154; 9.1%) (RR, 0.99; 95% CI, 0.36–2.70; p = 0.99). Therefore, the optimal timing of delivery at term for neonates with CDH remains unclear.     

A minority group's response to a severe climatic event: a case study of rural Indo-Fijians after Tropical Cyclone Winston in 2016

This paper investigates the impacts of Tropical Cyclone Winston (2016) on rural Indo-Fijians and their response to the devastation. Studies have previously examined how rural communities in Pacific Island countries respond to severe climatic events, arguing that traditional knowledge of the climate, together with indigenous techniques, contribute substantially to recovery from a disaster. Strong communal bonds have also been identified as an influencing factor. Disaster risk reduction frameworks often assume the availability of such knowledge and capital. Yet, little research has been done on how minority groups with limited access to such knowledge and capital cope with disaster-related damage. The current study shows that rural Indo-Fijians responded to the consequences of Tropical Cyclone Winston differently to indigenous Fijians, owing to relatively limited access to traditional awareness of the climate, communal labour sharing, and intra- and/or inter-community networks. The findings point to the necessity to implement a more inclusive disaster risk reduction framework.