This paper presents a new method of calculation of the change of axial twisting angle of compressed helical spring’s end-coils in the case of rotary - free supports. The propriety of derived formulas was experimentally verified. The method is easy in application and gives results much closer to experiment than the presently used method that can be found in literature.

Fieldexperiment with spring rape (Brassica napus var. oleifera f. annua) cultivars Star andLisonne was conductedin the years 1995–1999 at the vicinity of Olsztyn, Poland. The herbicides trifluralin (Triflurotox 250 EC), alachlor + trifluralin (Alatrif 380 EC), metazachlor (Butisan 400 SC) andclopyralid(Lontrel 300) were appliedin spring rape according to recommendations (Zalecenia 1993). The aim of this study was to estimate the effect of the herbicides on glucosinolates content in spring rape seeds. The obtainedresults revealedsignificant effect of meteorological conditions on glucosinolates content. The Star cv. was characterizedby higher level of these compounds in comparison with Lisonne cv. The adequate values were 15.96 μmol g^-1 of d.m. and 12.32 μmol g^-1 of d.m., respectively. It is evident on the base of the statistical analyses of the obtained results that herbicides modified glucosinolates content in seeds of both cultivars. The level of these compounds was increased as the effect of Triflurotox 250 EC use (data obtainedfrom three years investigations) and Alatrif 380 EC (four years) while Butisan 400 SC activity was unfavourable (four years).

Investigation of leaf rust disease on spring crops of triticale (× Triticosecale Wittm.), it sdi stribution dynamics, as well as the efficacy of two fungicides, different application doses and timing was carried out at the Lithuanian Institute of Agriculture during 2000–2002. Differences in the disease development were determined by the meteorological conditions, especially the amount of rainfall, and growth stage of plants. Precipitation during 2000 was close to the mean, and the development of leaf rust was moderate. In June of 2001 the rainfall was twice as high as the norm, which created favourable conditions for pathogen development. In 2002 a long droughty period till flowering inhibited the development of leaf rust. The triazole fungicides Juventus (metkonazole 60 g l^–1) and triazole and strobilurine mixture. Allegro (kresoxim-methyl 125 g l^–1 + epoxikonazole 125 g l^–1) were used at full, two-third and half doses once and twice. Both of the fungicides were very effective against leaf rust. Biological efficacy of Juventus applied at any dose or time against leaf rust was 88.3%–99.7%. Allegro efficacy against this disease was slightly higher 94.7%–100%. Application of 1.0; 0.75 and 0.5 l ha^–1 doses twice showed a better efficacy than a single application. The higher doses of fungicides were not markedly superior to the lower ones.

With the increasing penetration rate of grid-connected renewable energy generation, the problem of grid voltage excursion becomes an important issue that needs to be solved urgently. As a new type of voltage regulation control method, electric spring (ES) can alleviate the fluctuations of renewable energy output effectively. In this paper, the background and basic principle of the electric spring are introduced firstly. Then, considering the influence of an electric spring on noncritical load voltage, noncritical loads are classified reasonably, and based on the electric spring phasor diagram, the control method to meet the noncritical load voltage constraint is proposed. This control method can meet the requirements of voltage excursions of different kinds of noncritical load, increase the connection capacity of the noncritical load and improve the voltage stabilization capacity of the electric spring. Finally, through the simulation case, the feasibility and validity of electric spring theory and the proposed control method are verified.

Lublin Upland and Roztocze region are known for the occurrence of a large number of springs of high yield. These springs are fed mainly from Cretaceous or Tertiary water-bearing horizon. In order to determine variability of springs’ yield, 61 selected springs were analysed in spring periods of the years 1998–2008. Collected hydrometric materials allowed for comparing average and extreme yield values of springs in various physiographic regions within the period of 11 years. Average value was 76.1 dm3·s–1, while the mean of the minimal yields was 44.7 dm3·s–1 and of the maximal – 132.7 dm3·s–1. Coefficient of irregularity of the springs’ yield ranged from 1.5 to 5.0, which may lead to the conclusion that the springs’ yield is constant or varies slightly. In some cases the irregularity was higher but it was determined by hydrogeological, meteorological and local factors.

In order to help develop a better understanding of relevant catchment processes, this paper presents the changes in physico-chemical features of the Wieprz River water during the spring snowmelt flood of 2006. The obtained results showed that the groundwater sampled from the springs and the water sampled from the river had a similar and quite stable composition of the basic physicochemical features in the period of solely groundwater feeding (the river is fed only with the water coming from underground sources). The physico-chemical composition of river water during snowmelt depended on the contribution of surface runoff in total outflow and the flood phase. The correlation coefficients between the discharge in the Wieprz River and the concentrations in the studied indices were significantly negative: pH, SEC, HCO3, Ca, Mg, Na, Sr, SiO2, Cl, SO4, F. Significantly positive correlations associated with an increase in discharge were observed in the case of: K, NO3, NO2, total organic carbon, chemical oxygen demand and biochemical oxygen demand. Step and bidirectional responses were noted during the snowmelt flood in the case of the content of NH4 and PO4.

Water quality is an important criterion for evaluating the suitability of water for drinking and domestic purpose. The main objective of this study was to investigate the physicochemical characterization of groundwater for drinking water con-sumption. Ten captured sources were selected from three aquifers including the Guelma Mio-Plio-Quaternary alluvial ba-sin; the Senonian Heliopolis Neritic limestone aquifer, and the Eocene limestones of Ras El Agba-Sellaoua aquifer. The analyses concerned the periods of high water in May 2017 and low water in August 2017. Twelve parameters were deter-mined for the water samples: pH, T (°C), EC, Ca2+, Mg2+, Na+, K+, Cl–, HCO3–, SO42–, NO3–, TH (hydrotimetric degree), TAT (total alkalinity titration). The interpretation of the various analytical results allowed the determination of the chemical facies and the classification of the groundwater aquifers as follows: (i) in the alluvial layer, the gypsiferous marl substratum and the clays of the three terraces (high, medium and low) have given the water a chlorinated calcium chemical facies in the east part of the study area and travertines feeding partly alluvial layer, and have given a bicarbonated calcium water facies in the west, (ii) in the Senonian of Heliopolis limestone and Eocene carbonate formations of Ras El Agba- -Sellaoua, the chemical facies are calcium bicarbonate. Water isotopes (δ18O and δD) helped to determine the origin of groundwater. Overall, the groundwater in the area is hard and has significant to excessive mineralization. It is progressivelydegraded in the direction of flow, especially in the Guelma alluvial aquifer.

There are several springs with the large discharge around the Watuputih Karst Hills area that playing a crucial role in supplying water for both domestic and irrigation needs. The springs are located in the fault and fold zones of the Rembang anticlinorium system. This study was designed to determine the characteristics of karst aquifers from one year of monthly spatio-temporal data on discharge parameters and physico-chemical properties (temperature, pH, EC, Ca2+, Mg2+, HCO3–) of the four major springs, namely Brubulan Tahunan, Sumbersemen, Brubulan Pesucen, and Sendang Sayuran. It used sta-tistical calculations to characterize spring discharge and hydrochemical variations, as well as bivariate correlation analysis and flow-duration curve (FDC). The variability index (Iv), variability (V), and spring coefficient of variation parameters (SCVP) classified Brubulan Tahunan and Sumbersemen as springs producing stable, fairly constant discharge with low variations but characterized Brubulan Pesucen as having unstable, varying discharge with moderate variations. The results showed gently sloping hydrograph, low variations in discharge and hydrochemical properties, a relatively prolonged re-sponse of discharge and CO2-H2O-CaCO3 interaction to rainfall, and slope changes in the FDC. In other terms, although the springs are controlled by faults and folds, they have diffuse groundwater storage system in the form of densely fractured and porous media. These findings also indicate a less developed interconnected conduit, although Brubulan Pesucen is relatively more developed than Sumbersemen and Brubulan Tahunan. The geological structure and hydraulic gradient formed between the groundwater recharge and discharge areas are proven to control the amount of spring discharge actively.

This work deals with the effectiveness of a multi-body approach for the study of the dynamic behavior of a fixed landing gear, especially the research project concerns the drop tests of the AP.68 TP-300 aircraft. First, the Digital Mock-up of the of landing gear system in a C.A.D. software has been created, then the experimental structural stiffness of the leaf spring has been validated using the FEM tools MSC.Patran/Nastran. Finally, the entire model has been imported in MSC.ADAMS environment and, according to the certifying regulations, several multi-body simulations have been performed varying the heights of fall and the weights of the system. The results have shown a good correlation between numerical and experimental tests, thus demonstrating the potential of a multi-body approach. Future development of the present activity will probably be an application of the methodology, herein validated, to other cases for a more extensive validation of its predictive power and development of virtual certification procedures.

The paper focuses on a nonlinear model to represent the mechanical behaviour of a mix coil spring – rubber used in the secondary suspension of passenger rail vehicles. The principle of the model relies on overlapping of the forces corresponding to three components – the elastic component, the viscous component and the dry friction component. The model has two sources on non-linearity, in the elastic force and the friction force, respectively. The main attributes of the model are made visible by its response to an imposed displacement-type harmonic excitation. The results thus obtained from the applications of numerical simulation show a series of basic properties of the model, namely the dependence on amplitude and the excitation frequency of the model response, as well as of its stiffness and damping.

Glottal waveform models have long been employed in improving the quality of speech synthesis. This paper presents a new approach for modeling the glottal flow. The model is based on three control volumes that strike a one-mass and two-springs system sequentially and generate a glottal pulse. The first, second and third control volumes represent the opening, closing and closed phases of the vocal folds, respectively. The masses of the three control volumes and the size of the first one are the four parameters that define the shape, pitch and amplitude of the glottal pulse. The model may be viewed as parametric approach governed by second order differential equations rather than analytical functions and is very flexible for designing a glottal pulse. The glottal pulse generated by the present model, when compared with those generated by Rosenberg, LF and mucosal wave propagation models demonstrates that it appropriately represents the opening, closing and closed phases of the vocal fold oscillation. This leads to the validity of our model. Numerical solution of the present model has been found to be very efficient as compared to its analytical solution and two other well-known parametric models Rosenberg++ and LF. The accuracy of the numerical solution has been illustrated with the help of analytical solution. It has been observed that the accuracy improves by increasing the size of the first control volume and may decrease insignificantly with increase in the mass of any of the control volumes. Two experiments with the present model support its successful implementation as a voice source in speech synthesis. Thus our model renders itself as an efficient, accurate and realistic choice as a voice source to be employed in real-time speech production.

A low-dimensional physical model of small-amplitude oscillations of the vocal folds is proposed here. The model is a simplified version of the body-cover one in which mucosal surface wave propagation has been approximated by the seesaw-like oscillation of the vocal fold about its fulcrum point whose position is adjustable in both the horizontal and vertical directions. This approach works for 180 degree phase difference between the glottal entry and exit displacements. The fulcrum point position has a significant role in determining the shape of the glottal flow. The vertical position of the fulcrum point determines the amplitude of the glottal exit displacement, while its horizontal position governs the shape and amplitude of the glottal flow. An increment in its horizontal position leads to an increase in the amplitude of the glottal flow and the time period of the opening and closing phases, as well as a decrease in the time period of the closed phase. The proposed model is validated by comparing its results with the low-dimensional mucosal surface wave propagation model.

Stem base health of spring barley cultivated under organic, integrated and conventional systems and fungal communities were studied. A worst plant health status was observed in the organic system. The macroscopic and subsequent mycological analyses revealed the occurrence of Bipolaris sorokiniana and Fusarium spp. The incidence of B. sorokiniana on stem bases was clearly dependent on a farming system, and the highest incidence of this pathogen was observed in the organic system. Also, in that system, Fusarium spp. were isolated more numerously in the beginning of tillering, but in dough stage B. sorokiniana was the most prevalent pathogen, and Fusarium spp. were more numerous in integrated and conventional systems. It is worth to note that organic conditions could be favourable to Gliocladium spp. Because of growing interest in ecology, excluding the use of pesticides and increasing popularity of biological disease control, these antagonistic fungi could be useful in organic systems.

The main drawback of vibration-based energy harvesting is its poor efficiency due to small amplitudes of vibration and low sensitivity at frequencies far from resonant frequency. The performance of electromagnetic energy harvester can be improved by using mechanical enhancements such as mechanical amplifiers or spring bumpers. The mechanical amplifiers increase range of movement and velocity, improving also significantly harvester efficiency for the same level of excitation. As a result of this amplitude of motion is much larger comparing to the size of the electromagnetic coil. This in turn imposes the need for modelling of electromagnetic circuit parameters as the function of the moving magnet displacement. Moreover, high velocities achieved by the moving magnet reveal nonlinear dynamics in the electromagnetic circuit of the energy harvester. Another source of nonlinearity is the collision effect between magnet and spring bumpers. It has been shown that this effect should be carefully considered during design process of the energy harvesting device. The present paper investigates the influence of the above-mentioned nonlinearities on power level generated by the energy harvester. A rigorous model of the electromagnetic circuit, derived with aid of the Hamilton’s principle of the least action, has been proposed. It includes inductance of the electromagnetic coil as the function of the moving magnet position. Additionally, nonlinear behaviour of the overall electromagnetic device has been tested numerically for the case of energy harvester attached to the quarter car model moving on random road profiles. Such a source of excitation provides wide band of excitation frequencies, which occur in variety of real-life applications.