Use of isoperibolic calorimetry for the study of the effect of water concentration,temperature and reactor venting on the rate of hydroxylamine thermal decomposition

Hydroxylamine, NH₂OH, thermal decomposition has been responsible for two serious accidents. However, its reactive behavior and the synergy of factors affecting the rate of its decomposition are not understood. In this work, isoperibolic calorimetric measurements were performed in a metal reactor, in the temperature range 130–150 °C, employing 30–80 ml solutions containing 1.4–20 g of pure hydroxylamine (2.8–40 g of the supplied reagent). The calorimetric measurements were performed in order to assess the effects that NH₂OH concentration, temperature and reactor venting has on NH₂OH rate of decomposition. The measurements showed that increased concentration or temperature, results in faster reactions and probably higher pressure generation per mass of reactant, with concentration having a more pronounced effect. However, when both factors work synergistically the result is dramatically worse in terms of reaction rate. The pressure generation is also different, thus indicating that different reaction pathways predominate each time. Venting the produced gases in stages resulted in the highest mass loss of the solution.     

Use of magnesia for boron removal from irrigation water

The risk of B phytotoxicity due to high levels of B in irrigation water can be avoided by removing B from the water, before its use, through adsorption on certain adsorbents, such as magnesia (industrial MgO), if the latter can be proven to be an effective and easy to handle means for B removal. In addition, if such a material is applied as a fertilizer after its use and the adsorbed B is easily released into the soil solution, B phytotoxicity could constitute a potential hazard. The objectives of this work were to: (a) establish the optimum working conditions (equilibration time, solution to adsorbent ratio, and particle size of the adsorbent) for B adsorption, (b) assess the magnitude of B adsorption by magnesia, both in capacity and intensity terms, as well as the influence of temperature, (c) study B desorbability from magnesia, spiked with B at two rates, 5 and 0.5 mg g(-1), and (d) compare the results from b and c to those obtained using reagent grade MgO. The results showed that the time to achieve equilibrium depended on the B concentration of the external solution and ranged from 6 h (for B /= 50 mg L(-1)). The percentage of B adsorbed decreased as the volume of external solution to adsorbent increased and a working ratio of 50:1 was selected. For magnesia, B adsorption was particle size dependent with the smallest fraction (<0.1 mm) sorbing more B than the other three fractions studied (0.1-1.0, 1.1-2.0, 2.1-4.0 mm). Boron adsorption was conducted under strongly alkaline pH (10.3 +/- 0.2 and 10.4 +/- 0.1 for the reagent and magnesia, respectively) and increased with temperature. Both adsorbents exhibited a high B adsorption capacity (Langmuir maximum values were 5.85 +/- 0.39 and 4.45 +/- 1.31 mg B g(-1) for the reagent and magnesia, respectively) comparable to other metal oxides. However, the reagent grade MgO seemed to be superior to magnesia in terms of capacity and strength of B retention. This superiority of the reagent was attributed to its greater surface area (34.7 compared with 5.8 m(2) g(-1) for magnesia) and to its conversion to Mg(OH)(2) during the adsorption process, whereas magnesia remained unaltered, as was evident from X-ray diffractograms. Based on this data, magnesia seems to be an effective means for removing excess B from irrigation water, particularly if a material of fine particle size is used. Boron desorbability after 240 h of desorption time was more pronounced for magnesia reaching up to 55 and 60% of the amount of B added, at the spiked rates of 5 and 0.5 mg g(-1), respectively. Although these figures indicate that approximately half of the amount of B added remained adsorbed, they cannot be easily extrapolated to field conditions, and if B-laden magnesia is applied to soils, the possibility of B phytotoxicity cannot be excluded.     

Socioeconomic Dimensions of Changes in the Agricultural Landscape of the Mediterranean Basin: A Case Study of the Abandonment of Cultivation Terraces on Nisyros Island,Greece

Agricultural landscapes illustrate the impact of human actions on physical settings, and differential human pressures cause these landscapes to change with time. Our study explored changes in the terraced landscapes of Nisyros Island, Greece, focusing on the socioeconomic aspects during two time periods using field data, cadastral research, local documents, and published literature, as well as surveys of the islanders. Population increases during the late 19^th to early 20^th centuries marked a significant escalation of terrace and dry stone wall construction, which facilitated cultivation on 58.4% of the island. By the mid-20^th century, the economic collapse of agricultural activities and consequent emigration caused the abandonment of cultivated land and traditional management practices, dramatically reducing farm and field numbers. Terrace abandonment continued in recent decades, with increased livestock grazing becoming the main land management tool; as a result, both farm and pasture sizes increased. Neglect and changing land use has led to deterioration and destruction of many terraces on the island. We discuss the socioeconomic and political backgrounds responsible for the land-use change before World War II (annexation of Nisyros Island by the Ottoman Empire, Italy, and Greece; overseas migration opportunities; and world transportation changes) and after the war (social changes in peasant societies; worldwide changes in agricultural production practices). The adverse landscape changes documented for Nisyros Island appear to be inevitable for modern Mediterranean rural societies, including those on other islands in this region. The island’s unique terraced landscapes may qualify Nisyros to become an archive or repository of old agricultural management techniques to be used by future generations and a living resource for sustainable management.     

Organochlorine residues in blood of cinereous vultures and Eurasian griffon vultures in a northeastern Mediterranean area of nature conservation

In the National Park of Dadia-Lefkimi-Soufli Forest (Dadia NP, Greece), seven "target" PCBs and 16 organochlorine pesticides (OCs) were analysed in blood samples of cinereous vultures (Aegypius monachus) and Eurasian griffon vultures (Gyps fulvus). PCB congeners 138, 153 and 180 predominated in both species' blood samples. In both species, no differences were detected in congener levels between successive age classes, but in cinereous vulture, there were significant differences between adult and nestling in levels of PCB 28, 52, 101, 118 and between nestling and immature in levels of PCB 101. Regarding pesticides, p,p'-DDE dominated in both vultures followed by β-HCH, lindane and endosulfan sulphate, but ∑OCs were higher in griffon vulture. Significant differences were detected only between nestling and sub-adult cinereous vultures in heptachlor levels and between nestling and adult in p,p'-DDT. The origin of pollutants differs between the two vulture species and pollution patterns may not reflect those at Dadia NP.     

Social trends of the people of the region of Eastern Macedonia and Thrace-Greece: about the potential of using biofuels from forest products residues

In the framework of enquiry of biomass usage possibilities in our country, a research was made through the whole Eastern Macedonia region, related to disposal possibilities from the production conveyors and usage possibilities from the region’s residents and businessmen, of biofuels that come from mechanical wood treatment residues and from the residues of agricultural production, in wooden form, known with the term wood pellets or wood briquettes. From the present study, it came to light that there is an intense interest for direct personal usage and application of biomass for the residents or occupational spaces heating. The necessary biomass quantity for the entire region’s households is estimated up to 205,520 t. From the biomass usage as a combustible material, a 680 €/year and household about, is made. The potential investments that will be made to the region seem to have a very short depreciation, but a business plan and a marketing plan syntax are considered as necessary for the result’s maximisation.     

Correction to: Human behavior and Homo-mammal interactions at the first European peopling: new evidence from the Pirro Nord site (Apricena,Southern Italy)

The Science of Nature - Female-only colour polymorphism is rare in birds, but occurs in brood parasitic cuckoos (Cuculidae). Obligate brood parasites leave incubation and parental care to other...     

Characterization of extracellular polymeric substances (EPS) from periphyton using liquid chromatography-organic carbon detection–organic nitrogen detection (LC-OCD-OND)

A protocol was developed to extract, fractionate, and quantitatively analyze periphyton extracellular polymeric substances (EPS), which obtains both information on the molecular weight (M _r) distribution and protein and polysaccharide content. The EPS were extracted from freshwater periphyton between July and December 2011. Organic carbon (OC) compounds from different EPS extracts were analyzed using liquid chromatography-organic carbon detection–organic nitrogen detection (LC-OCD-OND), and total protein and polysaccharide content were quantified. Four distinct OC fractions, on the basis of M _r, were identified in all extracts, corresponding to high M _r biopolymers (≥80–4 kDa), degradation products of humic substances (M _r not available), low M _r acids (10–0.7 kDa), and small amphiphilic/neutral compounds (3–0.5 kDa). Low C/N ratios (4.3?±?0.8) were calculated for the biopolymer fractions, which represented 16–38 % of the measured dissolved organic carbon (DOC), indicating a significant presence of high M _r proteins in the EPS. Protein and polysaccharide represented the two major components of EPS and, when combined, accounted for the measured DOC in extracts. Differences in specific OC fractions of EPS extracts over the course of the study could be quantified using this method. This study suggests that LC-OCD-OND is a new valuable tool in EPS characterization of periphyton.     

Soil column experiments used as a means to assess transport,sorption, and biodegradation of pesticides in groundwater

Soil column experiments are used to investigate the fate of three pesticides of high, intermediate, and low solubility in groundwater: N- phosphonomethyl glycine (glyphosate); O,O-diethyl-S-[(ethylthio)methyl]phosphorodithioate (phorate); (2,4-dichlorophenoxy)acetic acid (2,4-D). Feed solutions are prepared by adding each pesticide (100 mg/L glyphosate, 50 μ g/L phorate, 50 mg/L 2,4-D) along with conservative tracer, KBr, in synthetic groundwater. The concentration of the pesticides in effluents is detected by ion chromatography (glyphosate, 2,4-D) and GC-FID (phorate). The Br^? breakthrough curves are employed to estimate the dispersion coefficient and mean pore velocity in each column. Solute transport and reactive models accounting for equilibrium/non-equilibrium sorption and biodegradation are coupled with inverse modeling numerical codes to estimate the kinetic parameters for all pesticides.     

Soil column experiments used as a means to assess transport, sorption, and biodegradation of pesticides in groundwater

Soil column experiments are used to investigate the fate of three pesticides of high, intermediate, and low solubility in groundwater: N- phosphonomethyl glycine (glyphosate); O,O-diethyl-S-[(ethylthio)methyl]phosphorodithioate (phorate); (2,4-dichlorophenoxy)acetic acid (2,4-D). Feed solutions are prepared by adding each pesticide (100 mg/L glyphosate, 50 micro g/L phorate, 50 mg/L 2,4-D) along with conservative tracer, KBr, in synthetic groundwater. The concentration of the pesticides in effluents is detected by ion chromatography (glyphosate, 2,4-D) and GC-FID (phorate). The Br(-) breakthrough curves are employed to estimate the dispersion coefficient and mean pore velocity in each column. Solute transport and reactive models accounting for equilibrium/non-equilibrium sorption and biodegradation are coupled with inverse modeling numerical codes to estimate the kinetic parameters for all pesticides.