Preparation and investigation of poly(methylmethacrylate) nano-capsules containing haloxyfop-R-methyl and their release behavior

Abstract

In this study, the preparation and characterization of haloxyfop-R-methyl herbicide loaded in poly(methylmethacrylate) (PMMA) nano-capsules by emulsion polymerization and its release behavior were investigated. The chemical characterizations of PMMA/haloxyfop-R-methyl nano-capsules were confirmed by FT-IR spectroscopy method, and the surface morphology was studied by field emission scanning electron microscopy and transmission electron microscopy. Also, the herbicide loading and encapsulation efficiency were analyzed for the herbicide-loaded nano-capsules. The release rate of PMMA/haloxyfop-R-methyl nano-capsules was determined by UV-visible spectroscopy. The thermal properties and thermal stability of nano-capsules were explored by the thermal gravimetric analysis method. The diameter of the nano-capsules was in the range of 100–300?nm. Increasing the amount of herbicide in nano-formulations significantly affected the surface of the nano-capsules and reduced their surface smoothness. Triton-X100 was identified as the best surfactant for the preparation of nano-capsules, and the sample containing the lowest herbicide content showed the best performance in terms of encapsulation and loading efficiency. This sample showed a steady-state release rate during the six days.     

The influence of processing and clarifier agents on the concentrations of potentially toxic elements (PTEs) in pekmez (a grape molasses-like syrup)

The changes in some potentially toxic elements (PTEs) including lead (Pb), cadmium (Cd), arsenic (As), iron (Fe), zinc (Zn), and copper (Cu) during pekmez (grape molasses-like syrup) processing and the utilization of various types of clarifiers (white soil, bentonite, and gelatin) in two levels (1.5 and 3% w/w) were analyzed. The average concentrations of Pb, Cd, As, Fe, Zn, and Cu in grape samples were measured as 0.055?±?0.005, 0.030?±?0.002, 0.044?±?0.002, 2.882?±?0.013, 2.372?±?0.088, and 1.194?±?0.01 μg g^?1. During pekmez production, the range of changes in Pb, Cd, As, Fe, Zn, and Cu was ?43.38% to 40.25%, ?55.49% to 0.23%, ?76.15% to 1.80%, ?74.15% to 58.47%, ?40.55% to ?18.12%, and ?83.16% to ?21.39%, respectively. The effect of the clarification process on the PTEs depended on the type and concentration of both PTE and clarifier agent used while the incorporation of gelatin resulted in a significant reduction in all of PT.

Graphical abstract

     

High-risk behaviors while driving: A population-based study from Iran

Objective: Traffic injuries are becoming one of the most important challenges of public health systems. Because these injuries are mostly preventable, the aim of this study is to evaluate the four main high-risk behaviors while driving.

Methods: This cross-sectional study was conducted on a random sample from the population of Mashhad, Iran, in 2014. A checklist and a previously validated questionnaire for the transtheoretical stages of change model (TTM) were used for data collection. Statistical analyses were performed using SPSS 11.5 software with P <.05 statistically significant.

Results: Totally 431 individuals were included with a mean age of 30 ± 11.3 years. Forty-three percent (183) were male. The TTM model revealed that participants were mostly in pre-actional phases regarding not using a cell phone while driving (80%), fastening the driver's seat belt (66%), front seat belt (68%), and rear seat belt (85%) The penalty was a protective factor only for using cellphone (odd ratio [OR] = 0.82, 95% confidence interval [CI], 0.68–0.98). Lower education (OR = 0.12, 95% CI, 0.01–0.94) and male gender (OR = 0.35, 95% CI, 0.14–0.83) were indicative of lower rates of fastening the front and rear seat belts.

Conclusion: The stages of change model among study participants is a proper reflection of the effectiveness of the current policies. More serious actions regarding these high-risk behaviors should be considered in legislation.     

Survey of discomfort glare from the headlamps of cars widely used in Iran

Objective: On 2-lane roads, discomfort glare can cause annoyance, discomfort, inconvenience, stress, and fatigue to drivers, posing a risk of accidents. The aim of this study is to evaluate discomfort glare from the headlamps of cars widely used in Iran.

Methods: The discomfort glare of new vehicles including Pride Saba model GTX, Pride Model 131SL, Samand Soren, Peugeot 405, Megane, and Peugeot Pars was examined at distances of 5 to 100 m at a background luminance of 50 cd/m² (late twilight/early dawn lighting) and 1 cd/m² (nighttime) using Schmidt-Clausen and Bindels model and de Boer's subjective scale.

Results: According to the de Boer scale, at a background luminance of 50 cd/m², the discomfort glare for all studied vehicles was between 1.98 and 4.05 in high-beam mode and between 3.5 and 5.4 in low-beam mode. At a background luminance of 1 cd/m², discomfort glare was between 0.41 and 2.48 in high-beam mode and between 1.93 and 3.84 in low-beam mode. In high-beam mode, the average levels of discomfort glare of these vehicles gradually increased when the distance between cars was reduced by up to about 20 m. In low-beam mode, there was no discomfort glare up to a vehicle distance of 40 m. In addition, at an angle of 1.15°–5.73° between the line of sight and light of vehicles in high-beam mode, the level of discomfort glare was increased, but at an angle of 5.73°–22.9° the level of discomfort glare was reduced. In low-beam mode at an angle of 2.86°–22.9°, the level of discomfort glare was almost identical. The results show that in high-beam mode and with a 100-m distance between vehicles as well as in low-beam mode at intervals of less than 40 m between cars, discomfort glare is created.

Conclusion: It can be concluded that by providing solutions such as installing road lighting system, an increase in luminance of roads, separating or widening road lanes, increasing the lateral distance between vehicles, and increasing the angle between lighted vehicles and drivers can noticeably reduce discomfort glare.     

Carbon sequestration via afforestation as a sustainable action to mitigate climate change in Western Iran

Climate change involves increasing atmospheric carbon dioxide concentration which is driven by anthropogenic emissions. Afforestation, which is the establishment of forests on previously non‐forested lands, could be a suitable climate change mitigation strategy. The aim of this research is to evaluate the carbon sequestration capability of the Eucalyptus and Prosopis species in the Reza‐Abad afforestation park in western Iran. For this aim, three stands of any species were selected. For quantitative assessment, a transect was implemented at the length of 100 m. In trees located of transects, the general characteristics of species were measured. Also, for estimating the amount of litter, a sample plot has been measured at the center of the quadrate. These samples were taken from the afforested area, the control area inside the afforested area and another control area outside. In each stand, species were selected randomly and one‐eighth of the whole stand was taken for calculating the percentage of carbon and aerial biomass. Then the aboveground organs were weighted and after the transfer of different plant organs to the laboratory, the conversion factor of carbon sequestration of the plant organs was determined individually by combustion method. Also, soil samples were also collected from two depths of 0–15 and 15–30 cm in each of the cultivated and control parts. The results showed that there is a significant difference between the species and Prosopis has higher carbon sequestration than Eucalyptus. The carbon sequestration among different organs showed a significant difference, carbon sequestration was 19.24 t/ha for Eucalyptus and 18.43 t/ha for Prosopis. After an economic calculation, it was concluded that afforestation has a positive effect on the reduction of atmospheric carbon dioxide. Hence, these results allow decision makers to change land use from desert area to forest, and planting the Prosopis species is more recommendable than Eucalyptus for afforestation in such areas which are economically profitable.     

Modelling the phytoplankton dynamics in a nutrient-rich solar saltern pond: predicting the impact of restoration and climate change

An ecological model for the solar saltern of Sfax (Tunisia) was established and validated by comparing simulation results to observed data relative to horizontal distributions of temperature, nutrients and phytoplankton biomass. Sensitivity analysis was performed in order to assess the influence of the main ecological model parameters. First applied at the saltern’s pond A1, the model was calibrated with field data measured over 4 years of study (from 2000 to 2003), which allowed an evaluation of parameters such as maximum growth rate of phytoplankton, optimal growth temperature and constant of half saturation for P/N assimilation by phytoplankton. Simulation results showed that the model allowed us to predict realistic phytoplankton variations of the study area, though we were unable to accurately reproduce the nutrient variation. The model was then applied to simulations of the impact of changes in phytoplankton biomass through scenarios such as hypothetic climate changes and saltern restoration.     

A development in energy flow/barrier analysis

In this paper, the occupational accidents and their effects on people are modeled. The basis of energy flow/barrier analysis is used to define an accident as the impact of a hazardous agent on a target, as a result of failure of control and protective barriers. This definition is enhanced to include serial and parallel barriers and to distinguish energy barriers from target barriers. The barrier attributes are defined and used to create a quantitative scenario-building model. The probability and severity of various accidents are estimated, by studying barrier reliability and efficiency. This approach is used to develop and simulate accident scenarios and to calculate their consequences. This model can be used in complex systems for analyzing the risk and estimating the importance of barriers.     

A sustainable sulfate process to produce TiO2 pigments

Titanium dioxide (TiO₂) is a widely used white pigment. TiO₂ production in 2006 was about 1,400,000 metric tons in the USA. The two major processes to manufacture TiO₂ are the chloride process and the sulfate process. Currently, the TiO₂ industry finds the waste generated in the chloride process less than the waste generated in the sulfate process in its present design, despite generating large quantities of process-related carbon dioxide and carbon monoxide. As a consequence, the sulfate process appears less economical, notably due to the production of green vitriol, FeSO₄·7H₂O, as a major waste. Here, we describe a more sustainable sulfate process based on an earlier study on thermal decomposition of iron(II) sulfates. In the sustainable sulfate process, FeSO₄·7H₂O waste is used for greener production of sulfuric acid, H₂SO₄, used in turn for the digestion of ilmenite. Theoretical and actual yields of waste byproducts per metric ton of TiO₂ produced are used to show the environmental and economic advantages of the sustainable sulfate process.     

A multi-criteria approach to screening alternatives for converting sewage sludge to biodiesel

The search for cheaper feedstock for use in the production of biofuels such as biodiesel has turned attention to various forms of waste products including animal fats, waste oils and now lipids in sludge. With the potential of obtaining sludge at a reduced cost, free, or possibly with incentives, sewage sludge is being investigated as a potential feedstock for biofuel production. For the extraction of oils from the sewage sludge and the subsequent processing, there are various alternatives that should be designed, analyzed, and screened. In developing and screening these alternatives, it is necessary to have a consistent basis for comparing alternatives based on key criteria. While most of the design studies focus on techno-economic criteria, it is also important to include safety metrics in the multi-criteria analysis. In this work, a detailed economic analysis and a safety evaluation are performed on a process involving extraction of triglycerides and fatty acids, pre-treatment of fatty acids (direct conversion to biodiesel), and transesterification of triglycerides to biodiesel. Four solvents, toluene, hexane, methanol and ethanol, are individually used in the extraction process. The resulting triglycerides and fatty acids from each extraction are modeled in the pre-treatment process. ASPEN Plus software is used to simulate the detailed process. Economic analysis is performed using ASPEN ICARUS, and scale-up of a previously analyzed process is used to estimate the cost of the biodiesel portion of the process. A new safety metric (referred to as the Safety Index “SI”) is introduced to enable comparison of the various solvent extraction processes. The SI is based on solvent criteria as well as process conditions. A case study is presented to demonstrate the insights and usefulness of the developed approach. The results of the techno-economic analysis reveal that of the four solvents used for the initial extraction, hexane and toluene were least costly (2.89 and 2.79 $/gal, respectively). Conversely, the safety analysis utilizing the SI reveals that methanol and ethanol are the safer solvent options. The issue of cost/safety tradeoffs is also discussed.     

Determinants of deforestation in Nepal's Central Development Region

The process of deforestation in the Central Development Region (CDR) of Nepal is diverse in space and time, with rapid deforestation still occurring in areas outside the national parks and wildlife reserves. This paper identifies the spatial driving forces (SDFs) of deforestation in the CDR for 1975–2000 using satellite data of 1975 (MSS), 1990 (TM), and 2000 (ETM+) along with socio-demographic and socioeconomic variables. Radiometrically calibrated satellite images are individually classified into seven distinct classes and merged together to cover the entire CDR. Classification accuracies are also assessed. Areas of land use and cover within the areas of each Village Development Committee (VDC) and municipality represented by GIS polygons are calculated from the classified images by overlaying vector files of 1845 polygons representing sections of VDCs and municipalities in 30–1199 m, 1200–2399 m, 2400–4999 m and >5000 m elevation levels. These elevation levels were estimated from the DEM compiled from 24 ASTER scenes taken on different dates. Only the first three elevation levels are used in the analysis because area >5000 m is under permanent snow cover where human related forestry activities are almost negligible. A transition matrix is generated for 1975–1990 using classified images of 1975 and 1990 and then this product is used to further develop another transition matrix for 1990–2000 with the classified ETM+ 2000 images as the final stage. The GIS polygon layer is overlaid on the transition matrices to calculate deforestation areas for 1975–1990 and 1990–2000. Biophysical and socioeconomic information collected from various sources is then brought into a GIS platform for statistical analyses. Six linear regression models are estimated using SAS; in effect, two models for each elevation range representing the 1975–1990 and 1990–2000 periods of change to identify SDF influences on deforestation. These regression analyses reveal that deforestation in the CDR is related to multiple factors, such as farming population, genders of various ages, migration, elevation, road, distance from road to forest, meandering and erosion of river, and most importantly the conversion of forestland into farmland.