Using Non-parametric Methods in Econometric Production Analysis: An Application to Polish Family Farms

Econometric estimation of production functions is one of the most common methods in applied economic production analysis. These studies usually apply parametric estimation techniques, which obligate the researcher to specify the functional form of the production function. Most often, the Cobb-Douglas or the Translog production function is used. However, the specification of a functional form for the production function involves the risk of specifying a functional form that is not similar to the “true” relationship between the inputs and the output. This misspecification might result in biased estimation results—including measures that are of interest of applied economists, such as elasticities. Therefore, we propose to use nonparametric econometric methods. First, they can be applied to verify the functional form used in parametric estimations of production functions. Second, they can be directly used for estimating production functions without specifying a functional form and thus, avoiding possible misspecification errors. We use a balanced panel data set of farms specialized in crop production that is constructed from Polish FADN data for the years 2004-2007. Our analysis shows that neither the Cobb-Douglas function nor the Translog function are consistent with the “true” relationship between the inputs and the output in our data set. We solve this problem by using non-parametric regression. This approach delivers reasonable results, which are on average not too different from the results of the parametric estimations but many individual results are rather different.Farm Management,

A new microwave ceramic - Polymer composite with 0-3 connectivity

Goal of the present research was to fabricate and study two-phase BiNbO4//PVDF composites with 0-3 connectivity. Such composite consists of there-dimensionally connected polymer matrix loaded with dielectric ceramic particles. In the present case BiNbO4 powder acted as an active phase(dispersed phase) whereas polyvinylidene fluoride (PVDF) acted as a non-active (passive) phase (matrix). BiNbO4//PVDF composites with the volume fraction of the ceramic phase cV =2, 4, 6, 8, 10, 16 and 20 vol. % were prepared. Average grain size of BiNbO4 powder was =1.86/m. It was found that BiNbO4 powder exhibited orthorhombic symmetry with Pnna (52) space group and PVDF polymer powder was α-phase. Minimum of dielectric losses at room temperature were found within the frequency range Δv =103-104 Hz. It was found that composite with cV =10% of ceramic powder exhibited lower values of dielectric permittivity

Influence of bismuth content on complex immittance characteristics of pressureless sintered BiNbO4 ceramics

Goal of the present research was to study immittance properties of BiNbO4 ceramics fabricated by the solid state reaction route followed by pressureless sintering. Four sets of samples were examined, namely the one fabricated from the stoichiometric mixture of oxides, viz. Bi2O 3 and Nb2O5 as well as the ones with an excess of 3%, 5% and 10% by mole of Bi2O3. The immittance properties were studied by impedance spectroscopy. Measurements were carried out within the frequency range T =20Hz-1MHz and temperature range T =RT-550°C. The Kramers-Kronig data validation test was employed in the impedance data analysis. It was found that complex impedance first increases with an increase in Bi2O3 content and decreases for 10mol% excess of Bi2O3. Two relaxation phenomena manifested themselves at elevated temperature (T >267°C) within the measuring frequency range. The conductivity relaxation phenomenon (M′′(v) spectra) took place at higher frequency than the phenomenon with dominant resistive component (Z′′(v) spectra)

Fabrication and Crystal Structure of Sol-Gel Deposited BST Thin Films with Compositional Gradient

In the present research technology of compositionally graded barium strontium titanate Ba1-xSrxTiO3 thin films deposited on stainless steel substrates by sol-gel spin coating followed with thermal annealing at T = 650°C is reported. Results of thermal behavior of the sol-gel derived powders with compositions used for fabrication of graded structure (i.e. with Sr mole fraction x = 0.5, 0.4 and 0.3) are described. X-ray diffraction studies of the phase composition and crystal structure of such complex thin film configuration are given. It was found that gel powders exhibited a large total weight loss of about Δm ≈ 44-47%. Three stages of weight loss took place at temperature ranges: below T ≈ 300°C, at ΔT ≈ 300-500°C and between T = 600°C and T = 800°C. Phase analysis has shown that the dominating phase is Ba0.67Sr0.33TiO3 compound while the second phase is Ba0.7Sr0.3TiO3 or Ba0.5Sr0.5TiO3 for "up-graded" and "down-graded" structure, respectively

Weather derivatives as an instrument of weather risk management

Ryzyko pogodowe ma coraz większy wpływ na funkcjonowanie współczesnych przedsiębiorstw. Aby skutecznie zarządzać ryzykiem pogodowym, przedsiębiorstwa mogą korzystać z pogodowych instrumentów pochodnych. W artykule podjęto próbę klasyfikacji podmiotów, które mogłyby wykorzystać w ramach procesu zarządzania ryzykiem pogodowym instrumenty pochodne, a szczególnie opcje pogodowe. Na wstępie przedstawiono istotę ryzyka pogodowego, formułując jego definicję oraz klasyfikując to zjawisko. Następnie dokonano wyszczególnienia tych podmiotów, na które pogoda wpływa w sposób istotny. Dalej zaprezentowano opcję pogodową, zaczynając od konstrukcji tego instrumentu, poprzez historię jego funkcjonowania na rynku światowym, a kończąc na refleksjach na temat możliwości zastosowania opcji pogodowych w polskich realiach.Weather risk has an increasing impact on the functioning of today’s enterprises. To manage weather risk effectively companies may use weather derivatives. This article attempts to classify entities that could be used as part of weather risk management derivatives, especially weather derivatives. At the outset it presents the essence of weather risk, defining and classifyingthis phenomenon. This is followed by a description of those entities on which the weather has a significant effect. Next weather derivatives are presented, starting with the construction of the instrument, through the history of weather derivatives on the world market, and ending with a reflection on the applicability of weather derivatives in a Polish context

Effect of Bi2O3 excess on morphology and structure of BiNbO4 ceramics

Goal of the present research was to fabricate BiNbO4 ceramics from the mixture of powders by the solid state reaction route and pressureless sintering at various temperatures (Ts =870°C and Ts =910°C) and study microstructure, phase composition and crystalline structure of BiNbO4 ceramics. Four batches were fabricated and examined, namely the one fabricated from the stoichiometric mixture of reagent - grade oxide powders, viz. Bi203 and Nb20 5 as well as the ones with an excess of 3%, 5% and 10% by mole of Bi2O3. It was found that apart from the main orthorhombic a-BiNb04 phase additional phases, namely tetragonal Bi 5Nb3015, and cubic Bi3NbO 7 are possible to form from the mixture of bismuth oxide and niobium oxide. It was found that α-BiNbO4 ceramics exhibited the orthorhombic symmetry identified as Pnna (52). However, small differences in elementary cell parameters were found for the samples sintered from stoichiometric and non-stoichiometric mixture of initial powders