Determination of As(III) and As(V) in oilseeds by chronopotentiometric stripping analysis: development of a method

Chronopotentiometric stripping analysis (CSA) was used for selective determination of As(III) and As(V) in different oilseeds. After the optimization of experimental parameters an appropriate procedure for sample pretreatment was developed. A detection limit of 2 microg/dm3 for As(III) was obtained with an electrolysis time of 600 s. This method was used for arsenic determination in sunflower, pumpkin, and flax seed, as well as for soy flakes and almond.     

Catalytic pyrolysis and kinetic study of real-world waste plastics: multi-layered and mixed resin types of plastics

Clean Technologies and Environmental Policy - Multi-layered and mixed resin types of plastics are a great challenge for the waste recycling industry. The majority consist of two or more types of...     

Depolarization current of novolac phenol-formaldehyde resins doped with 1,4-diazabicyclo [2.2.2] octane

Mixtures of novolac phenol-formaldehyde (NPF) resins and 1,4-diazabicyclo [2.2.2] octane (DABCO) were polarized at different temperatures applying different d. c. electric fields. Thermally stimulated depolarization current (TSDC) measurements performed from 298 to 373 K showed a dipolar α peak and a space charge α peak as in pure NPF. The addition of DABCO decreases the magnitude of the α peak and the activation energy of the dipolar relaxation but increases the background current and the magnitude of the α peak significantly. The maximum of the α peak is only slightly shifted towards higher temperatures. New aspects in the analysis of the background current by consecutive heating and cooling experiments are considered. The results obtained show an increase in concentration of trapping sites due to the heterogeneity of the mixed systems. The proposed interactions between nitrogen from DABCO and hydroxy groups from NPF are discussed.     

Verifying Relative Safety,Accuracy, and Termination for Program Approximations

Approximate computing is an emerging area for trading off the accuracy of an application for improved performance, lower energy costs, and tolerance to unreliable hardware. However, developers must ensure that the leveraged approximations do not introduce significant, intolerable divergence from the reference implementation, as specified by several established robustness criteria. In this work, we show the application of automated differential verification towards verifying relative safety, accuracy, and termination criteria for a class of program approximations. We use mutual summaries to express relative specifications for approximations, and SMT-based invariant inference to automate the verification of such specifications. We perform a detailed feasibility study showing promise of applying automated verification to the domain of approximate computing in a cost-effective manner.     

Curing of resole-type phenol–formaldehyde resin

The process of resole-type phenol–formaldehyde resins was studied by differential thermal analysis and infrared spectroscopy. It was shown that in neutral media the first reactions that occur are those between free phenol present in the resin and monosubstituted methylol phenol with free reactive positions on the benzene ring. The formation of methylene linkages is followed immediately by the condensation of methylol groups to give dibenzyl ether linkages. These are subsequently destroyed at about 210°C. It is believed that the entire curing process is governed by a free-radical mechanism. It is also shown that oxidation of the resin occurs slowly at room temperature and humidity.     

Flow of solids in an interconnected fluidized beds system investigated using positron emission particle tracking

The technique of Positron Emission Particle Tracking (PEPT) is applied to analyse non‐intrusively solids flow in a laboratory scale Interconnected Fluidized Beds system. It is shown that, with a high performance tracking system, it is possible to extract from the data not only the Eulerian ensemble average velocity field, but also to reconstruct density profiles and to calculate mass flows in a solids circulation system. The most interesting flow characteristics inside the Interconnected Fluidized Bed system are highlighted. Although the data analysis is largely Eulerian, a first approach to a Lagrangian analysis has been performed through the computation of velocity autocorrelation functions. Characteristic frequencies of the solids movement could not be identified, but the velocity autocorrelations did provide insight in the dynamics of the solids movement.     

Proving termination of nonlinear command sequences

We describe a simple and efficient algorithm for proving the termination of a class of loops with nonlinear assignments to variables. The method is based on divergence testing for each variable in the cone-of-influence of the loop’s condition. The analysis allows us to automatically prove the termination of loops that cannot be handled using previous techniques. We also describe a method for integrating our nonlinear termination proving technique into a larger termination proving framework that depends on linear reasoning.     

War Damages and Reconstruction of Peru?a Dam

The paper describes the heavy damages caused by blasting in the Peru?a rockfill dam in Croatia in January 1993. Complete collapse of the dam by overtopping was prevented through quick action of the dam owner by dumping clayey gravel on the lowest sections of the dam crest and opening the bottom outlet of the reservoir, thus efficiently lowering the water level. After the damages were sufficiently established and alternatives for restoration of the dam were evaluated, it was decided to construct a diaphragm wall through the damaged core in the central dam part as the impermeable dam element and to rebuild the central clay core at the dam abutments. Reconstruction works are described.     

Rheology and morphology of poly(vinyl acetate) + calcite films

We have studied mechanical and rheological behavior of poly(vinyl acetate) (PVAC) composites filled with calcite as a function of filler particle geometry, particle size distribution, and active surface area. Detailed morphological characteristic were investigated. Tensile properties of PVAC composites were evaluated in the composition range 5–20 wt% calcite. The elongation at break decreases as consequence of matrix mobility restriction by filer particles. By contrast, the strength at break increases as a result of fewer stress concentration points produced by small calcite particles. Large calcite particles decrease the strength of the PVAC composite because of lack of structural continuity. Failure is then dominated by the dewetting. Understanding the deformation as it relates to structure, mechanism of failure, and strength of interactions makes development of improved PVAC composites for adhesives possible.     

Hybrid RES-HEP Systems Development

An inherent characteristic of renewable energy sources (RES)-based electricity generation systems is intermittency and non-controllability. Therefore, the prerequisite for a more significant use of RES within the energy system is the corresponding capacity of Electric Energy Storage (EES). The existing storage of Hydro Electric Power (HEP) is suggested as a possible solution to this issue. The paper contains a detailed analysis of the possible joint operation of Photovoltaic (PV) generator and HEP. The key element of this scenario is the HEP storage that would serve as EES. The analysis of the possible joint operation of the PV generator and HEP shows it as a natural, feasible and very acceptable solution that would enhance the features of both energy sources. Joint operation would increase the energy production sustainability, cut volatility and increase reliability, and therefore the value of the RES energy, as well as the efficiency of the HEP. The application of the hybrid system will significantly contribute to the share of RES in the energy system and thus to achieving the climate protection objectives.