Catch Crops in Organic Farming Systems without Livestock Husbandry - Model Simulations

During the last years, an increasing number of stockless farms in Europe converted to organic farming practice without re-establishing a livestock. Due to the lack of animal manure as a nutrient input, the relocation and the external input of nutrients is limited in those organic cropping systems. The introduction of a one-year green manure fallow in a 4-year crop rotation, including clover-grass mixtures as a green manure crop is the classical strategy to solve at least some of the problems related to the missing livestock. The development of new crop rotations, including an extended use of catch crops and annual green manure (legumes) may be another possibility avoiding the economical loss during the fallow year. Modelling of the C and N turnover in the soil-plant-atmosphere system using the soil-plant-atmosphere model DAISY is one of the tools used for the development of new organic crop rotations. In this paper, we will present simulations based on a field experiment with incorporation of different catch crops. An important factor for the development of new crop rotations for stockless organic farming systems is the expected N mineralisation and immobilisation after incorporation of the plant materials. Therefore, special emphasise will be put on the simulation of N-mineralisation/-immobilisation and of soil microbial biomass N. Furthermore, particulate organic matter C and N as an indicator of remaining plant material under decomposition will be investigated

Application of PSO to Design UPFC-based Stabilizers

Today, power demand grows rapidly and expansion in transmission and generation is restricted with the limited availability of resources and the strict environmental constraints. Consequently, power systems are today much more loaded than before. In addition, interconnection between remotely located power systems turned out to be a common practice. These give rise to low frequency oscillations in the range of 0.1-3.0 Hz. If not well damped, these oscillations may keep growing in magnitude until loss of synchronism results. Power system stabilizers (PSSs) have been used in the last few decades to serve the purpose of enhancing power system damping to low frequency oscillations. PSSs have proved to be efficient in performing their assigned tasks. The objective of this chapter is to investigate the potential of particle swarm optimization as a tool in designing UPFC-based stabilizers to improve power system transient stability. To estimate the controllability of each of the UPFC control signals on the electromechanical modes, singular value decomposition is employed. The problem of designing all the UPFCbased stabilizers individually is formulated as an optimization problem. Particle swarm optimizer is utilized to search for the optimum stabilizer parameter settings that optimize a given objective function. Coordinated design of the different stabilizers is also carried out by finding the best parameter settings for more than one stabilizer at a given operating condition in a coordinated manner

Effective Robotics Education: Surveying Experiences of Master Program Students in Introduction to Robotics Course

© The Authors, published by EDP Sciences, 2018. Technology-driven world poses new challenges for the modern education system. To prepare skilled specialists for academic and industrial needs it is important to create competitive educational ground. Our team works on developing and implementing world-class master program in Intelligent Robotics. To pave the way for a high-quality educational program we invest efforts into studying students' attitude and motivation for connecting their professional life with robotics. In this paper we describe the curriculum for master program that was designed and implemented at the Higher Institute of Information Technology and Information Systems at Kazan Federal University and present the results of our continuous research of comparative analysis of surveys among students of Introduction to Robotics course

Visions of a more precise soil biology

Includes bibliographical references (pages 389-390).Soils have often been viewed as a black box. Soil biology is difficult to study with the precision we would wish, due to the presence of considerable soil heterogeneity, a huge diversity of organisms, and a plethora of interacting processes taking place in a complex physical-chemical environment. We have isolated a tiny fraction of the known organisms, and the possible interactions of soil parent materials, landscape, land use, depth and time with the biota mean that we are to some extent still fumbling in the dark. There have been great advances, but we argue that the pace of advance could be faster. To progress, science needs new theory and concepts but also acceptable methodologies. Coherent and generally accepted theoretical knowledge exists in many areas, but there is a shortage of valid and exact methods to test new and sometimes even old hypotheses. New methods add knowledge, but they also can add to the confusion if they are not tied to the existing knowledge base. We speculate on how to improve soil biology through improving the way we perform and interpret research. Can we deal with soil variability? Can we measure the critical variables with adequate precision to test our hypotheses? Can we avoid reinventing the wheel? Can we find a balance between the freedom to test new and maybe even controversial ideas and the control and direction of research required by society?

Stark Effect of Interactive Electron-hole pairs in Spherical Semiconductor Quantum Dots

We present a theoretical variational approach, based on the effective mass approximation (EMA), to study the quantum-confinement Stark effects for spherical semiconducting quantum dots in the strong confinement regime of interactive electron-hole pair and limiting weak electric field. The respective roles of the Coulomb potential and the polarization energy are investigated in details. Under reasonable physical assumptions, analytical calculations can be performed. They clearly indicate that the Stark shift is a quadratic function of the electric field amplitude in the regime of study. The resulting numerical values are found to be in good agreement with experimental data over a significant domain of validity

Comparison of Inappropriate Shocks and Other Health Outcomes Between Single- and Dual-Chamber Implantable Cardioverter-Defibrillators for Primary Prevention of Sudden Cardiac Death: Results from the Cardiovascular Research Network Longitudinal Study of Implantable Cardioverter-Defibrillators

Background In US clinical practice, many patients who undergo placement of an implantable cardioverter‐defibrillator (ICD) for primary prevention of sudden cardiac death receive dual‐chamber devices. The superiority of dual‐chamber over single‐chamber devices in reducing the risk of inappropriate ICD shocks in clinical practice has not been established. The objective of this study was to compare risk of adverse outcomes, including inappropriate shocks, between single‐ and dual‐chamber ICDs for primary prevention. Methods and Results We identified patients receiving a single‐ or dual‐chamber ICD for primary prevention who did not have an indication for pacing from 15 hospitals within 7 integrated health delivery systems in the Longitudinal Study of Implantable Cardioverter‐Defibrillators from 2006 to 2009. The primary outcome was time to first inappropriate shock. ICD shocks were adjudicated for appropriateness. Other outcomes included all‐cause hospitalization, heart failure hospitalization, and death. Patient, clinician, and hospital‐level factors were accounted for using propensity score weighting methods. Among 1042 patients without pacing indications, 54.0% (n=563) received a single‐chamber device and 46.0% (n=479) received a dual‐chamber device. In a propensity‐weighted analysis, device type was not significantly associated with inappropriate shock (hazard ratio, 0.91; 95% confidence interval, 0.59–1.38 [P=0.65]), all‐cause hospitalization (hazard ratio, 1.03; 95% confidence interval, 0.87–1.21 [P=0.76]), heart failure hospitalization (hazard ratio, 0.93; 95% confidence interval, 0.72–1.21 [P=0.59]), or death (hazard ratio, 1.19; 95% confidence interval, 0.93–1.53 [P=0.17]). Conclusions Among patients who received an ICD for primary prevention without indications for pacing, dual‐chamber devices were not associated with lower risk of inappropriate shock or differences in hospitalization or death compared with single‐chamber devices. This study does not justify the use of dual‐chamber devices to minimize inappropriate shocks

Simultaneous Stabilization Of Power System Using UPFC-Based Controllers

This article studies the use of robust UPFC-based stabilizers to damp low frequency oscillations. The potential of the UPFC-based stabilizers to enhance the dynamic stability is evaluated by singular value decomposition. Particle swarm optimization technique is used to optimize the parameters of each stabilizer, first individually, then concurrently. To ensure the robustness of the proposed stabilizers, the design process considers a wide range of operating conditions. The effectiveness of the proposed controllers is verified through several linear and nonlinear analysis techniques. These techniques prove that the coordinated design of UPFC-based stabilizers is superior over any of the individual designs

Simultaneous Stabilization Of Power System Using UPFC-Based Controllers

This article studies the use of robust UPFC-based stabilizers to damp low frequency oscillations. The potential of the UPFC-based stabilizers to enhance the dynamic stability is evaluated by singular value decomposition. Particle swarm optimization technique is used to optimize the parameters of each stabilizer, first individually, then concurrently. To ensure the robustness of the proposed stabilizers, the design process considers a wide range of operating conditions. The effectiveness of the proposed controllers is verified through several linear and nonlinear analysis techniques. These techniques prove that the coordinated design of UPFC-based stabilizers is superior over any of the individual designs

Impaired Chronotropic Response to Exercise Stress Testing in Patients With Diabetes Predicts Future Cardiovascular Events

OBJECTIVES— To assess the association between impaired chronotropic response (CR) and adverse events among patients with diabetes referred for exercise treadmill testing (ETT)

Modelling and simulation of hollow profile aluminium extruded product

The main objectives of this paper is to find the way for solving the problems of aluminum extrusion process, and improve the mechanical properties of the products through a smart design, modelling and simulation of this process by using finite element method (FEM). For the purpose to model a (2D) two dimensions warm aluminum extrusion process, ABAQUS software was used to set up the finite element simulation. The main parameters which have major effects on this process like extrusion stresses, temperature, and die geometry, i.e. extrusion radius, were taken into consideration. Aluminum alloy (Al-2014) was used as the billet material, with 40 mm diameter and 75 mm length. It is important to preheat the billet from the beginning to a specific temperature, and then pressurizes it into the die. This process is an isothermal process with an extrusion ratio of 3.3. Subsequently, the optimized algorithm for these extrusion parameters was suggested based on the simulation results. The results suggest that the large die angle needs a less extrusion load than the small die angle. In all die geometry used, the deformation of aluminum billet, which caused by shearing and compression stresses, happened in a small sectional area, i.e., bearing area. The results also showed that the values of these stresses can increase or decrease depends on the die entrance angle and the die bearing length. To avoid the effects of these stresses on die dimensions; the hardness, material selection, and geometry should be well calculated