Fil: Mendieta, Carolina Monica. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Nordeste. Instituto de Materiales de Misiones. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Quimicas y Naturales. Instituto de Materiales de Misiones; Argentina

Review: Bio-polyethylene from Wood Wastes

Increased demand for a more balanced, healthy, and safe diet has accelerated studies on natural bee products (including honey, bee bread, bee collected pollen royal jelly, propolis, beeswax, and bee venom) over the past decade. Advanced food processing techniques, such as ultrasonication and microwave and infrared (IR) irradiation, either has gained popularity as alternatives or combined with conventional processing techniques for diverse applications in apiculture products at laboratory or industrial scale. The processing techniques used for each bee products have comprehensively summarized in this review, including drying (traditional drying, infrared drying, microwave-assisted traditional drying or vacuum drying, and low temperature high velocity-assisted fluidized bed drying), storage, extraction, isolation, and identification; the assessment methods related to the quality control of bee products are also fully mentioned. The different processing techniques applied in bee products aim to provide more healthy active ingredients largely and effectively. Furthermore, improved the product quality with a shorter processing time and reduced operational cost are achieved using conventional or emerging processing techniques. This review will increase the positive ratings of the combined new processing techniques according to the needs of the bee products. The importance of the models for process optimization on a large scale is also emphasized in the future.

Processing Technologies for Bee Products: An Overview of Recent Developments and Perspectives.

Different methods for galvanically isolated monitoring of the mains voltage waveform were evaluated. The aim was to determine the level of distortion of the output signal relative to the input signal and the suitability of each method for calculating active power values. Six fixtures were tested: two voltage transformers, an electronic circuit with a current transformer, a standalone current transformer, a simple circuit with optocouplers, and a circuit with an A/D-D/A converter with capacitive coupling. The input and output waveforms were mathematically analyzed by three methods: (1) calculating the spectral components of waveforms and the relative changes in their THD (total harmonic distortion) values, (2) determining the similarity of waveforms according to the size of the area bounded by the input and output waveform curves, and (3) determining the accuracy of the active power calculation based on the output waveform. The time difference in the zero crossing of the input and output signals was measured, and further calculations for the second and third method were performed on the zero-crossing time shift-corrected waveforms. Other aspects of selecting the appropriate type of monitoring element, such as power consumption or overall circuit complexity, were also evaluated.

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Analysis of Output Signal Distortion of Galvanic Isolation Circuits for Monitoring the Mains Voltage Waveform

Land-Use competitiveness of photovoltaic and concentrated solar power technologies near the Tropic of Cancer

The aim of this study was to acquire data on the physical properties and mechanical behaviour of the six seed corn hybrid varieties. One variety was semi-flint, while others were dent types. The mean values of length, width, thickness, geometric diameter, surface area, porosity, single kernel mass, sphericity, bulk and true density, 1000 kernel weight and coefficient of friction were studied at a single level of moisture content. The longest kernels were those of the ZP 677 hybrid, which ranged from 10.51-11.50 mm in length. The largest width was observed for ZP 684 (7.51-8.50 mm) and ZP 677 (6.51-7.25 mm) kernels, while kernel thickness was greatest in ZP 434 (3.56-4.55 mm) and ZP 684 (3.31-5.55 mm) hybrids. The mean geometric diameters were 7.18; 7.15; 6.91 and 6.72 mm for NS 4015, ZP 644, NS 640 and ZP 677, respectively. The highest value of sphericity, 0.75, was measured for ZP 684, followed by 0.71 for NS 640; the hybrids NS 6010 and ZP 677 had the lowest value of sphericity (0.60). The measured bulk density values ranged from 784.75 kg/m3 (ZP 677) and 779.58 kg/m3 to 633.56 kg/m3 (NS 6010), while true densities ranged from 1176.63 kg/m3 (ZP 677) and 1175.65 kg/m3 (NS 640) to 900.94 kg/m3 (NS 6010). The linear model showed a decreasing tendency of secant modulus of elasticity for all ZP hybrids as the moisture content of seeds increased, with high values of the coefficient of regression. Similar results were attained for NS hybrids but with lower coefficient of regression values.

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Physical properties and compression loading behaviour of corn (Zea mays L.) Seed

Energy balance of the photovoltaic system is influenced by many factors. In this article the effect of tilt and azimuth angle changes of the photovoltaic system energy production is analyzed. These parameters have significant impact on the amount of solar radiation which hits on the photovoltaic panel surface and therefore also on the energy absorbed by the module surface. The main aim of research was identification of the optimal position of photovoltaic system installation in the southern Slovakia regions. The experimental apparatus had two setups consisting of polycrystalline photovoltaic modules. The first setup was used for identification of the tilt angle changes in the range (0–90°). The second one was focused on the detection of the azimuth angle effect to the energy production. The measurement results were statistically processed and mathematically analyzed. Obtained dependencies are presented as two-dimensional and three-dimensional graphical relations. Regression equations characterize time relations between the tilt or azimuth angle and the energy produced by the photovoltaic system in Southern Slovakia. Obtained simplified mathematical model was verified by analytical model. Presented models can be used for the dimensioning and optimization of the photovoltaic system energy production.

The Effect of Azimuth and Tilt Angle Changes on the Energy Balance of Photovoltaic System Installed in the Southern Slovakia Region

Knowledge of bee products’ physical properties has a decisive importance for the monitoring of their quality. Thermophysical parameters are very important properties. Thermal conductivity and thermal diffusivity of selected bee products (honey, bee pollen and perga) were measured by two different methods. For identification of thermal conductivity and thermal diffusivity transient methods were used: Hot Wire (HW) and Dynamic Plane Source (DPS) method with an instrument Isomet 2104. The principle of measuring process is based on the analysis of timetemperature relation. In the first series of measurements thermal conductivity and diffusivity at constant laboratory temperature of 20 °C were measured. The second series was focused on identification of the changes in the thermophysical parameters during temperature stabilisation in the temperature range of 5–25 °C. For samples with constant temperature standard deviations and probable errors in % were calculated. For relations of thermal parameters to temperature graphical dependencies were obtained. Two different thermophysical methods were used for improvement of data reliability and data statistics.

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Thermal properties of selected bee products.

This paper deals with assessment of density, moisture content and mechanical properties of pellets made of dry swine manure utilizing pellet production line MGL 200. Pellets were subsequently subjected to compressive loading test. Furthermore, the values obtained were measured by means of device Andilog Stentor 1000 and compression diagrams were plotted. In terms of compressive strength, pellet type 1 showed value of 10.47 MPa; pellet type 2 showed value of 6.24 MPa. Considering the elasticity modulus, pellet type 1 showed value of 122.39 MPa; pellet type 2 showed value of 71.12 MPa. Other observed properties included force necessary for 10% compression strain; force in the first maximum of force-strain curve; force in the inflection point of the force-time curve. Results obtained from compressive loading test provide a basis for innovations in pellet production utilizing materials other than wood biomass.

Evaluation of Properties of Pellets Made of Swine Manure

http://www.international-agrophysics.org/pdf-142472-69553?filename=Thermal properties of.pdf

Thermal properties of wood and wood composites made from wood waste

The paper deals with the evaluation of the mechanical properties of the polyethylene foils such as the stress, strain, modulus of elasticity and stress and strain in the moment of breaking. The thin foils (50 mm) which contained 91 % of polyethylene Bralen RA 2–63 and 9 % colored concentrate Maxithen were studied. Four sorts of foils were examined: Maxithen HP 1510 – white, Maxithen HP 231111 – yellow, Maxithen HP 533031 – blue and Maxithen HP 533 041 – violet. Longitudinal and transversal tensile properties were studied. The tensile behavior was monitored on the motorized test stand ANDILOG STENTOR 1000. The moduli of elasticity of longitudinal samples of polyethylene Bralen RA 2—63 foils achieved the values in the range from 222.73 MPa to 298.24 MPa and the transversal samples in the range 179.61 MPa to 270.41 MPa. The stress of longitudinal samples of polyethylene Bralen RA 2–63 foils in the moment of the rupture achieved the values in the range from 9.46 MPa to 13.33 MPa at the strain from 1.51 mm*mm–1 to 1.54 mm*mm–1 and the transversal samples in the range from 12.38 MPa to 15.54 MPa at the strain from 1.48 mm*mm–1 to 1.58 mm*mm–1.

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Ľubomír Kubík

Papers

The Effect of Azimuth and Tilt Angle Changes on the Energy Balance of Photovoltaic System Installed in the Southern Slovakia Region

Thermal properties of selected bee products.

Evaluation of Properties of Pellets Made of Swine Manure

Thermal properties of wood and wood composites made from wood waste

Mechanical properties of polyethylene foils