Motorcyclist perception response time in stopping sight distance situations

One of the most effective engineering measures is the provision of an exclusive motorcycle lane that separates motorcycles from other mixed traffic to reduce traffic congestion and motorcycle crashes. Even though the existing exclusive motorcycle lanes in Malaysia reduced the incidents of motorcycle crashes with other vehicles, the design of this special motorcycle lane was based on a cross reference between a bicycle track and a highway. Thus, a suitable design guide is yet to be developed for the geometrical design of a proper and safer exclusive motorcycle lane. Safe stopping sight distance (SSD) has been recognized as a criterion for road design and should be taken into account. Motorcyclist perception response time (PRT) is the time from detection object until the rider reduces motorcycle speed in braking action is an essential component of motorcycle SSD. Two road experiments were conducted to obtain empirical values of motorcycle PRT to expected and unexpected objects. In the expected condition, 89 motorcyclists applied brake as quickly as possible following activation of a light beside the road. In the unexpected condition, 16 riders responded by braking in response to an obstacle that appeared suddenly in their lane. The mean PRT to expected and unexpected object is 0.71 s and 1.25 s respectively. The 85th percentile PRT to unexpected object is 2.12 s. This study found that most riders are capable of responding to an unexpected object along the roadway in 2.5 s or less. Therefore, PRT of 2.5 s is an appropriate value for motorcycle lane geometric design.     

Microbial quality and physical–chemical characteristics of thermal springs

Microbial quality and physical–chemical properties of recreational spas were surveyed to investigate the health aspect of the spas’ water. A total of 195 samples were collected from pools and springs of the spas in five sites from Ardebil Province of Iran. The effects of an independent factor defined as ‘condition’ and its component sub-factors (i.e., sampling point, location, and sampling date) on microbial quality and physical–chemical properties of the spas were studied by applying path analysis. The influence of physical–chemical properties on microbial quality was also considered. The percentage of samples exceeding the ISIRI (Swimming pool water microbiological specifications (vol 9412), Institute of Standards and Industrial Research of Iran, Tehran, 2007) limits for Staphylococcus (spp.) was up to 55.8 in the springs and 87.8 in the pools, 58.1 and 99.2 for HPC, 90.7 and 97.8 for total coliform and fecal coliform, and 9.3 and 34.4 for Pseudomonas aeruginosa, respectively. There were significant differences between the pools and springs for both physical–chemical properties and microbial quality. From the path analysis, sampling point was the most effective sub-factor of ‘condition’ on both the physical–chemical properties and microbial quality. Among the physical–chemical properties, water color had the most enhancing or additive influence on microbial pollution, while EC indicated a reducing or subtractive effect.     

Numerical study of scouring downstream of a stilling basin

Environmental Fluid Mechanics - The aim of the present study is to numerically investigate the scouring phenomenon downstream of a stilling basin for a wide range of Froude number and size of bed...     

Relationship of firm attributes,ownership structure and business network on climate change efforts: evidence from Malaysia

This paper presents a case study of land-use/land-cover (LULC) changes from 1975 to 2014 in the central highlands of Ethiopia and traces out its impact on socioeconomic conditions of the local community in the study area. We used four time series Landsat satellite images, that is, Landsat MSS (1975), Landsat Thematic Mapper (1986), Enhanced Thematic Mapper (2000), and Landsat 8 OLI scenes (2014), to investigate the changes in LULC. In addition, individual interviews with 51 randomly selected households, discussions with focus group and key informants, and field observations were also incorporated for the study. The image classification indicated four categories of LULC classes: Natural forest, eucalyptus plantations, cropland/settlements, and grasslands. Between 1975 and 2014, cropland/settlements and eucalyptus plantations considerably increased, whereas grassland cover drastically decreased. According to the results, the area under cropland/settlements and eucalyptus plantations increased by 62 and 335%, respectively, with 74% concomitant decrease in the area of grasslands in the same period. Survey results showed that deterioration of soil fertility (41.2%) followed by shortage of land (35.3%) is the major constraint for crop production for poor farmers in the study area. However, better-off farmers ranked deterioration of soil fertility (64.7%) followed by lack of credit (17.6%) as priority constraints for crop production. Interviews mainly focused on selected women group revealed that the expansion of eucalyptus in the area greatly curbed the burdens of collecting fuel woods from long distances in the past. The availability of too many religious holidays (on average 16 days/month) directly or indirectly contributes to the current seasonal food shortages of the community. Generally, our results show that the community in the study area is beset with a host of social, economic, and institutional challenges. As a result, majority of the farming households are destitute, unable to make a livelihood from their small plot of land and live in absolute poverty. Therefore, in light of these finding, it is imperative that timely interventions by government and other development stakeholders are needed to come to grips with problems of soil fertility, land-use change, and food insecurity in the study area.     

Geochemical fractions and phytoavailability of Zinc in a contaminated calcareous soil affected by biotic and abiotic amendments

Many studies have conducted to determine the best management practice to reduce the mobility and phytoavailability of the trace metals in contaminated soils. In this study, geochemical speciation and phytoavailability of Zn for sunflower were studied after application of nanoparticles (SiO₂ and zeolite, with an application rate of 200 mg kg^?1) and bacteria [Bacillus safensis FO-036b(T) and Pseudomonas fluorescens p.f.169] to a calcareous heavily contaminated soil. Results showed that the biotic and abiotic treatments significantly reduced the Zn concentration in the aboveground to non-toxicity levels compared to the control treatment, and the nanoparticle treatments were more effective than the bacteria and control treatments. The concentration of CaCl₂-extractable Zn in the treated soils was significantly lower than those of the control treatment. The results of sequential extraction showed that the maximum portion of total Zn belonged to the fraction associated with iron and manganese oxides. On the contrary, the minimum percent belonged to the exchangeable and water-soluble Zn (F₁). From the environmental point of view, the fraction associated with iron and manganese oxides is less bioavailable than the F₁ and carbonated fractions. On the basis of plant growth promotion, simultaneous application of the biotic and abiotic treatments significantly increased the aboveground dry biomass yield and also significantly reduced the CaCl₂-extractable form, uptake by aboveground and translocation factor of Zn compared to the control treatment. Therefore, it might be suggested as an efficient strategy to promote the plant growth and reduce the mobile and available forms of toxic metals in calcareous heavily contaminated soils.     

Effects of nitrogen treatments and harvesting stages on the aconitic acid, invert sugar and fiber in sweet sorghum cultivars

Sweet sorghum is adapted to the hot and dry climatic conditions and its tolerance to slat is moderately. It can be used for different products such as food, feed, fiber and fuel. This study was carried out to evaluate the effects, three nitrogen treatments, and three harvesting stages on the aconitic acid, fiber and invert sugar of three sweet sorghum cultivars in the experimental station and the results showed that the effects were significant. Among nitrogen treatments, application of 100 kg ha(-1) urea at planting and 200 kg ha(-1) urea at 4 leaf stage had the highest aconitic acid (0.26%) and invert sugar (3.44%). Among sweet sorghum cultivars, IS2325 and Vespa had the highest aconitic acid (0.26%) and invert sugar (3.86%), respectively Plant harvested at 4 leaf stage had the highest aconitic acid (0.26%) and the highest invert sugar (3.85%). Rio had higher fiber content than Vespa and IS2325 and all cultivars had the highest fiber content before chilling harvesting stage. In general, since high invert sugar and high aconitic acid interfere crystallization of sugar so, it is suggested that to plant Vespa, apply urea 100 kg ha(-1) urea at planting, 100 kg ha' urea at 4 leaf stage and 100 kg ha(-1) urea at booting and harvested before chilling that had lowest aconitic acid and invert sugar. Thereby, it is recommended to plant Vespa, apply urea 100 kg ha(-1) urea at planting, 100 kg ha(-1) urea at 4 leaf stage and 100 kg ha(-1) urea at booting and harvested at 4 leaf stage that had the highest aconitic acid.     

Phosphorus loss to runoff water twenty-four hours after application of liquid swine manure or fertilizer

Phosphorus (P) added to soil from fertilizer or manure application could pose a threat to water quality due to its role in eutrophication of fresh water resources. Incorporating such amendments into the soil is an established best management practice (BMP) for reducing soluble P losses in runoff water, but could also lead to higher erosion. The objective of this study was to test whether incorporation of manure or fertilizer 24 h before an intense rain could also reduce sediment-bound and total phosphorus (TP) losses in runoff. A rainfall simulation study was conducted on field plots (sandy loam with 6-7% slope, little surface residue, recently cultivated) that received two application rates of liquid swine manure or liquid ammonium polyphosphate fertilizer, using either surface-broadcast or incorporated methods of application. Incorporation increased the total suspended solids (TSS) concentrations in runoff but mass losses were not affected. Incorporation also reduced flow-weighted concentrations and losses of dissolved reactive phosphorus (DRP) and TP by as much as 30 to 60% depending on source (fertilizer vs. manure) and application rate. Phosphorus is moved below the mixing zone of interaction on incorporation, and thus the effect of the amount and availability of P in this zone is more important than cultivation on subsequent P losses in runoff. Incorporating manure or fertilizer in areas of intense erosive rain, recent extensive tillage, and with little or no surface residue is therefore a best management practice that should be adhered to in order to minimize contamination of surface water. Results also show comparatively lower P losses from manure than fertilizer.     

Plant growth regulators and EDTA improve phytoremediation potential and antioxidant response of Dysphania ambrosioides (L.) Mosyakin & Clemants in a Cd-spiked soil

Environmental Science and Pollution Research - Soil pollution due to potentially toxic elements is a worldwide challenge for health and food security. Chelate-assisted phytoextraction along with...