A multi-agent simulation model for spatial optimisation of manure allocation

The EU Nitrate Directive has spurred many countries to regulate manure production and manure application. Farmers have three allocation options: spreading manure on their own land, transporting manure to other farmers' land or processing manure. The manure problem can be seen as an allocation problem. To better understand this allocation problem, we have developed the spatial mathematical programming multi-agent simulation (MP-MAS) model. This model has been applied in Flanders, Belgium, a region with a high concentration of livestock. The model evaluates the cost efficiency of policy intervention in the manure market through obliged processing. We propose to further optimise the policy using a regionally differentiated manure pressure indicator, which is directly derived from the dual outcome of the mathematical programme. This indicator increases transparency in the manure and processing market, leading to better decision support about location and type of manure processing.     

Nanocomposites of Cellulose Acetate Butyrate Reinforced with Cellulose Nanocrystals

Nanocrystals were prepared by acid hydrolysis of bacterial cellulose microfibrils. These were topochemically trimethylsilylated, in an attempt to reduce their hydrophilicity. Composites were made by dispersing either native or silylated crystals in cellulose acetatebutyrate matrixes and solution casting of the dispersions. Particles were characterized by transmission electron microscopy. The composites were characterized by differential scanning calorimetry and dynamic mechanical analysis. The unmodified cellulose crystals exhibited better reinforcement characteristics than the trimethylsilated crystals.     

Ultrafine particles at workplaces of a primary aluminium smelter

The number concentration and size distribution of ultrafine particles in a S?derberg and a prebake potroom of an aluminium primary smelter have been measured using a scanning mobility particle spectrometer. The particle morphology was studied by transmission electron microscopy (TEM). The study shows the existence of elevated number concentrations of ultrafine particles in both potrooms. The main source of these particles is likely to be the process of anode changing. The ultrafine particles were measured directly at the source but could also be identified as episodes of high number concentrations in the general background air. Unlike the larger particles belonging to the 50-100 nm mode, the nanoparticle mode could not be detected in the TEM indicating that they may not be stable under the applied sampling conditions and/or the high vacuum in the instrument.     

Soil organic carbon and nitrogen accumulation in plots of rhizoma perennial peanut and bahiagrass grown in elevated carbon dioxide and temperature

Carbon sequestration in soils might mitigate the increase of carbon dioxide (CO2) in the atmosphere. Two contrasting subtropical perennial forage species, bahiagrass (BG; Paspalum notatum Flügge; C4), and rhizoma perennial peanut (PP; Arachis glabrata Benth.; C3 legume), were grown at Gainesville, Florida, in field soil plots in four temperature zones of four temperature-gradient greenhouses, two each at CO2 concentrations of 360 and 700 micromol mol(-1). The site had been cultivated with annual crops for more than 20 yr. Herbage was harvested three to four times each year. Soil samples from the top 20 cm were collected in February 1995, before plant establishment, and in December 2000 at the end of the project. Overall mean soil organic carbon (SOC) gains across 6 yr were 1.396 and 0.746 g kg(-1) in BG and PP, respectively, indicating that BG plots accumulated more SOC than PP. Mean SOC gains in BG plots at 700 and 360 micromol mol(-1) CO2 were 1.450 and 1.343 g kg(-1), respectively (not statistically different). Mean SOC gains in PP plots at 700 and 360 micromol mol(-1) CO2 were 0.949 and 0.544 g kg(-1), respectively, an increase caused by elevated CO2. Relative SON accumulations were similar to SOC increases. Overall mean annual SOC accumulation, pooled for forages and CO2 treatments, was 540 kg ha(-1) yr(-1). Eliminating elevated CO2 effects, overall mean SOC accumulation was 475 kg ha(-1) yr(-1). Conversion from cropland to forages was a greater factor in SOC accumulation than the CO2 fertilization effect.     

The Steubenville Comprehensive Air Monitoring Program (SCAMP): analysis of short-term and episodic variations in PM2.5 concentrations using hourly air monitoring data

One-hour average ambient concentrations of particulate matter (PM) with an aerodynamic diameter < 2.5 microm (PM2.5) were determined in Steubenville, OH, between June 2000 and May 2002 with a tapered element oscillating microbalance (TEOM). Hourly average gaseous copollutant [carbon monoxide (CO), sulfur dioxide (SO2), nitrogen oxide (NOx), and ozone (O3)] concentrations and meteorological conditions also were measured. Although 75% of the 14,682 hourly PM2.5 concentrations measured during this period were < or = 17 microg/m3, concentrations > 65 microg/m3 were observed 76 times. On average, PM2.5 concentrations at Steubenville exhibited a diurnal pattern of higher early morning concentrations and lower afternoon concentrations, similar to the diurnal profiles of CO and NO(x). This pattern was highly variable; however, PM2.5 concentrations > 65 microg/m3 were never observed during the mid-afternoon between 1:00 p.m. and 5:00 p.m. EST. Twenty-two episodes centered on one or more of these elevated concentrations were identified. Five episodes occurred during the months June through August; the maximum PM2.5 concentration during these episodes was 76.6 microg/m3. Episodes occurring during climatologically cooler months often featured higher peak concentrations (five had maximum concentrations between 95.0 and 139.6 microg/m3), and many exhibited strong covariation between PM2.5 and CO, NO(x), or SO2. Case studies suggested that nocturnal surface-based temperature inversions were influential in driving high nighttime concentrations of these species during several cool season episodes, which typically had dramatically lower afternoon concentrations. These findings provide insights that may be useful in the development of PM2.5 reduction strategies for Steubenville, and suggest that studies assessing possible health effects of PM2.5 should carefully consider exposure issues related to the intraday timing of PM2.5 episodes, as well as the potential for toxicological interactions among PM2.5, and primary gaseous pollutants.     

Genuine modern analogues of Precambrian stromatolites from caldera lakes of Niuafoʻou Island, Tonga

Calcareous or dolomitic, often secondarily silicified, laminated microbial structures known as stromatolites are important keys to reconstruct the chemical and biotic evolution of the early ocean. Most authors assume that cyanobacteria-associated microbialitic structures described from Shark Bay, Western Australia, and Exuma Sound, Bahamas, represent modern marine analogues for Precambrian stromatolites. Although they resemble the Precambrian forms macroscopically, their microstructure and mineralogical composition differ from those characterizing their purported ancient counterparts. Most Precambrian stromatolites are composed of presumably in situ precipitated carbonates, while their assumed modern marine analogues are predominantly products of accretion of grains trapped and bound by microbial, predominantly cyanobacterial, benthic mats and biofilms and only occasionally by their physicochemical activity. It has therefore been suggested that the carbonate chemistry of early Precambrian seawater differed significantly from modern seawater, and that some present-day quasi-marine or non-marine environments supporting growth of calcareous microbialites reflect the hydrochemical conditions controlling the calcification potential of Precambrian microbes better than modern seawater. Here we report the discovery of a non-marine environment sustaining growth of calcareous cyanobacterial microbialites showing macroscopic and microscopic features resembling closely those described from many Precambrian stromatolites.     

Are older drivers’ driving patterns during an on-road driving task representative of their real-world driving patterns?

Abstract

Objective: The current study investigated whether older drivers’ driving patterns during a customized on-road driving task were representative of their real-world driving patterns.

Methods: Two hundred and eight participants (male: 68.80%; mean age?=?81.52 years, SD?=?3.37 years, range?=?76.00–96.00 years) completed a customized on-road driving task that commenced from their home and was conducted in their own vehicle. Participants’ real-world driving patterns for the preceding 4-month period were also collected via an in-car recording device (ICRD) that was installed in each participant’s vehicle.

Results: During the 4-month period prior to completing the on-road driving task, participants’ median real-world driving trip distance was 2.66?km (interquartile range [IQR]?=?1.14–5.79?km) and their median on-road driving task trip distance was 4.41?km (IQR?=?2.83–6.35?km). Most participants’ on-road driving task trip distances were classified as representative of their real-world driving trip distances (95.2%, n?=?198).

Conclusions: These findings suggest that most older drivers were able to devise a driving route that was representative of their real-world driving trip distance. Future research will examine whether additional aspects of the on-road driving task (e.g., average speed, proportion of trips in different speed zones) are representative of participants’ real-world driving patterns.