Influence of beam butt face nonparallelism on free damped vibration spectrum of the beam

Introduction. The free vibration method is widely applied to detecting internal defects in rod and lamellar structural elements. In this work, it is used to diagnose a rod sample defect consisting in nonparallelism of the rod ends. The possibility of identifying a defect in the form of a bevel of one of the rod butts by the frequency spectrum of free damped longitudinal and transverse vibration after impact actions to the rod side or butt face is considered. Materials and methods. An experimental facility and a method of contact-free recording of the frequency spectrum of the rod natural vibration by its acoustic radiation spectrum are presented. Signs of a defect in the form of a split frequency of the rod transverse vibration are detected. At the same time, the maximum amplitudes of the split frequencies correspond to higher or lower frequencies depending on the face to which the impact is applied. This allows not only determining the presence of a defect in the form of the bevelled butt face, but also establishing its orientation relative to the side rod faces. Results. An approximate theoretical model is suggested. It explains the effect of frequency splitting in the presence of nonparallelism of the rod butts. For this, the frequency spectra of transverse vibration of two rods with lengths equal to the lengths of the smaller and the larger faces of the original rod with the bevel edge are considered. Experiments show that the differences in the natural frequencies of the bending vibration of these rods, which correspond to the same eigenmodes, are consistent with the differences in the split frequencies of the free damped transverse vibrations of the bevelled-face rod. At this, relationship between the split frequency amplitudes allows determining not only the presence of bevelled face, but also its location. Conclusions. The application and development of the method through the analysis of the natural vibration spectrum can lead to creation of remote quality control equipment for rod structural elements.

RESIDUAL DE NANOPARTICULADO NA CORREÇÃO DO SOLO E NPK NA CULTURA DO CAFÉ

A maior parte das lavouras de café brasileiras estão localizadas em solos ácidos, onde pode-se observar baixos teores de macronutrientes, e grande quantidade de alumínio trocável, que vem a afetar o desenvolvimento dos cafeeiros, e por consequência afetando a absorção de nutrientes e água. Esse trabalho teve como objetivo avaliar a eficiência da tecnologia de nanoparticulado na correção do solo e NPK, buscando a dosagem e parcelamento de aplicação correta para maior eficiência. O Delineamento estatístico do experimento foi em Blocos Casualizados (DBC), com arranjo fatorial em faixas (“strip-plot”) dos 16 tratamentos, 3 repetições por tratamento, totalizando 48 parcelas experimentais. A tecnologia foi avaliada em análise de duas fontes de variação: D - diferentes doses do produto recomendado e P - parcelamento da dosagem ou intervalo de aplicação. Cada fonte de variação apresentando 4 (quatro) tratamentos, sendo eles: D1 – dose 5 l.ha-1; D2 – dose 10 l.ha-1; D3 – dose 15 l.ha-1 e D4 - dose 18 l.ha-1 para D. E P1 - uma parcela; P2 - duas parcelas (aplicação a cada 6 meses); P3 - três parcelas (aplicação a cada 4 meses) e P4 - quatro parcelas (aplicação a cada 3 meses) para P. A tecnologia de nanoparticulado testado, nas dosagens de 10 a 15 l.ha-1, em 2 a 3 aplicações ao ano, mostraram efeitos positivos e suficientes para suprir as necessidades de correções da acidez do solo, para cultura do café conilon, no período de um ano agrícola e nas condições de cultivo.PALAVRA-CHAVES: Calagem, Fertirrigação, Parcelamento NANOPARTICLE RESIDUAL IN SOIL CORRECTION AND NPK FERTILIZATION OF COFFEEABSTRACT: Most of Brazil’s coffee is grown in acidic soils, with low macronutrient concentrations and high exchangeable aluminum, which affect the development of coffee trees and, hence, the absorption of nutrients and water. The objective of this study was to evaluate the efficiency of the nanoparticle technology in the soil correction and NPK fertilization, seeking the adequate rate and split application frequency to increase fertilizer use efficiency. The experiment was arranged in a factorial strip-plot randomized block design (RBD), with 16 treatments and 3 replicates per treatment, totaling 48 experimental plots. The technology was assessed by analyzing two sources of variation: D - different rates of the product recommended; and P - splitting the rate or application frequency. Each source of variation was subjected to 4 (four) treatments: D1 - 5 l ha-1; D2 - 10 l ha-1; D3 15 l ha-1, and D4 18 l ha-1 for rates D; and P1 – one split; P2 - two splits (application every 6 months); P3 - three splits (application every 4 months); and P4 - four splits (application every 3 months) for split frequency P. The use of the nanoparticle technology at the rates of 10 to 15 l ha-1 in 2 to 3 split applications per year provided positive and adequate effects to meet the acidity correction requirements for Conilon coffee crop, during an agricultural year and in the study cultivation conditions.KEYWORDS: Liming, Fertigation, Split application.

NANOPARTICULADO NO FORNECIMENTO DE Ca E Mg NA CULTURA DO CAFÉ VIA FERTIRRIGAÇÃO

Das tecnologias usadas para aumentar a produtividade e a rentabilidade das culturas agrícolas, a calagem e adubação do solo se destacam entre as principais. Assim a necessidade de encontrar corretivos e fertilizantes com mais eficiência e menos onerosos caracteriza a realidade da agricultura brasileira. Além do calcário, outros materiais corretivos vêm surgindo como opção de uso. Esse trabalho teve como objetivo avaliar a eficiência da tecnologia de nanoparticulado na correção da acidez do solo e fornecimento do Ca e Mg, sendo este produto avaliado em análise de duas fontes de variação: D - diferentes doses do produto recomendado e P - parcelamento da dosagem ou intervalo de aplicação. Cada fonte de variação apresentando quatro 4 tratamentos, sendo eles: D1 – dose 5 l.ha-1; D2 – dose 10 l.ha-1; D3 – dose 15 l.ha-1 e D4 - dose 18 l.ha-1 para D. E P1 - uma parcela; P2 - duas parcelas (aplicação a cada 6 meses); P3 - três parcelas (aplicação a cada 4 meses) e P4 - quatro parcelas (aplicação a cada 3 meses) para P. O Delineamento estatístico do experimento foi em Blocos Casualizados (DBC), com arranjo fatorial em faixas (“strip-plot”) dos 16 tratamentos, 3 repetições por tratamento, totalizando 48 parcelas experimentais. Os resultados obtidos com tecnologia do nanoparticulado testado, nas dosagens de 10 a 15 l.ha-1, em 2 a 3 aplicações ao ano, tem efeitos positivos e suficientes para suprir as demandas de Ca2+ e Mg2+ no solo e na planta para cultura do café conilon, no período de um ano agrícola e nas condições de cultivo.PALAVRA-CHAVES: Calagem, Adubação, Nanopartículas. NANOPARTICULATE IN THE SUPPLY OF Ca AND Mg IN COFFEE CULTURE VIA FERTIRRIGATIONABSTRACT: Of all technologies used to increase productivity and profitability of agricultural crops, soil liming and fertilization stand out among the main ones. Thus, the need to find correctives and fertilizers less costly and more efficient characterizes the reality of Brazilian agriculture. The objective of this work was to evaluate the efficiency of the nanoparticulate technology in the correction of soil acidity and the supply of Ca and Mg. , The technology was assessed by analyzing two sources of variation: D - different rates of the product recommended; and P - splitting the rate or application frequency. Each source of variation was subjected to 4 (four) treatments: D1 - 5 l ha-1; D2 - 10 l ha-1; D3 15 l ha-1, and D4 18 l ha-1 for rates D; and P1 – one split; P2 - two splits (application every 6 months); P3 - three splits (application every 4 months); and P4 - four splits (application every 3 months) for split frequency P. The experiment was arranged in a factorial strip-plot randomized block design (RBD), with 16 treatments and 3 replicates per treatment, totaling 48 experimental plots. Dosages of 10 to 15 l ha-1 , in 2 to 3 applications per year, had positive and sufficient effects to supply the demands of Ca2+ and Mg2+ for Conilon coffee crop , during an agricultural year and in the study cultivation conditions.KEYWORDS: Liming, Fertilization, Nanoparticles.

Complexity Analysis of Electroencephalogram Dynamics in Patients with Parkinson’s Disease

In this study, a new combination scheme has been proposed for detecting Parkinson’s disease (PD) from electroencephalogram (EEG) signal recorded from normal subjects and PD patients. The scheme is based on discrete wavelet transform (DWT), sample entropy (SampEn), and the three-way decision model in analysis of EEG signal. The EEG signal is noisy and nonstationary, and, as a consequence, it becomes difficult to distinguish it visually. However, the scheme is a well-established methodology in analysis of EEG signal in three stages. In the first stage, the DWT was applied to acquire the split frequency information; here, we use three-level DWT to decompose EEG signal into approximation and detail coefficients; in this stage, we aim to remove the useless and noise information and acquire the effective information. In the second stage, as the SampEn has advantage in analyzing the EEG signal, we use the approximation coefficient to compute the SampEn values. Finally, we detect the PD patients using three-way decision based on optimal center constructive covering algorithm (O_CCA) with the accuracy about 92.86%. Without DWT as preprocessing step, the detection rate reduces to 88.10%. Overall, the combination scheme we proposed is suitable and efficient in analyzing the EEG signal with higher accuracy.

High linearity lead-lag style envelope modulator for RF power amplifiers

A new split frequency envelope modulator for envelope tracking radio-frequency power amplifiers is proposed based on a lead-lag network. By mathematically deriving the transfer functions of the lead-lag modulator and the conventional split frequency type, the lead-lag is shown to have a significantly flatter phase response. The frequency response of the two modulators is verified by simulation, where the phase transient of the lead-lag is significantly less than the 360° of the conventional type. They are further simulated with a 3 MHz bandwidth 3GPP long-term evolution (LTE) signal and the lead-lag shown to reduce the modulator's normalized root-mean-square error (NRMSE) from −27.3 to −39.2 dB. A practical demonstrator was developed around an existing high-efficiency modulator architecture. To maintain system efficiency synthetic impedance was incorporated in the low-frequency switched mode power supply (SMPS) path. This was achieved with voltage and current feedback around the SMPS. The dynamic wideband signal response was investigated by applying a 3 MHz LTE envelope signal to the modulator and comparing the input and output signals. The measured NRMSE was improved from −27.5 to −30.0 dB by adopting the lead-lag structure and the dynamic frequency response verifies correct operation.