821 research outputs found
The impact of economic policies over the agricultural sector in the southern hemisphere: The case of Argentina, 1980 - 2006
The aim of this paper is to analyze the impact of the economic policies on the Argentinean Agricultural sector for the period 1980-2007. By evaluating the changes that have been taken place in the production styles and the role played by the rise in profitability of cereals, oleaginous crops and beef cattle, we seek to identify the main elements that will allow us to understand the general path that the sector has taken for the period under analysis. After explaining the general evolution of the sector, we end up our analysis identifying the future challenges that the country will face regarding food security, health regulations and environmental problems.agriculture, livestock, profitability, food security, Argentina.,
Hydrokinetic turbine composite blades and sandwich structures: Damage evaluation and numerical simulation
“Composite materials are gaining interest due to their high strength to weight ratio. This study deals with both experimental and numerical approaches to cover the aspects of the failure of composite materials in hydrokinetic turbine applications. In Part I, the location and magnitude of failure in the horizontal axis water turbine carbon fiber-reinforced polymer (CFRP) composite blades with different laminate stacking sequences were investigated. Two lay-up orientations were adopted for this work ([0⁰]4 and [0⁰/90⁰]2s). A finite element analysis model was generated to examine the stresses along the blade. Five angles were introduced to study the effect of pitch angle on the CFRP blades. The numerical results showed very good agreement with the experimental results. In Part II, an experimental setup was developed to test the delamination progression in CFRP blades under hydrodynamic loads in a water tunnel. Thermography analysis was employed to scrutinize the propagation of delamination. In addition, a computational fluid dynamics and one-way fluid-structure interaction were developed to predict the stresses along the blade. The unidirectional ([0⁰]4) blades showed the best performance while the cross-ply blades ([0⁰/90⁰]2s) are prone to delamination. In Part III, the effect of increasing the contact area between the core and facesheet was studied. Two tests (impact and flat-wise tension) were carried out to examine the integrity of the structure. A finite element model was developed to study the damage due to localized load, such as impact load. The results obtained from both the tests (impact and flatwise tension) showed that increasing surface area had improved the structural integrity in regards to damage resistance due to impact, and delamination resistance between the facesheet and the core due to tension”--Abstract, page iv
Preparation, Characterization and NO-CO Redox Reaction Studies over Palladium and Rhodium Oxides Supported on Manganese Dioxide
The catalytic activity of PdO/MnO2 and Rh2O3/MnO2 is investigated for NO-CO redox reaction. Supported catalysts are prepared by wet impregnation method. Among the tested catalysts, PdO/MnO2 shows higher activity for this reaction. Active metal dispersion on MnO2 enhances the selectivity for N2 over N2O in this reaction. The XRD substantiate the formation of MnO2 monophasic phase. SEM images show the formation of elongated particles. TEM images indicate nano-size rod-like morphologies. An increase in the catalytic activity is observed on supported Pd and Rh oxides on MnO2. Temperature programed desorption studies with NO and CO are undertaken to investigate the catalytic surface studies. © 2015 BCREC UNDIP. All rights reserve
INVESTIGATION AND PENETRATION OF DIGITAL ATTACKS ON ZIGBEE-BASED IOT SYSTEMS
The market for Internet of Things (IoT) products and services has grown rapidly. It has been predicted that the deployment of these IoT applications will grow exponentially in the near future. However, the rapid growth of IoT brings new security risks and potentially opens up new types of attacks for systems and networks. This article outlines various techniques to carry out attacks on ZigBee-based IoT systems. We conducted penetration experiments on various possible attacks on Zigbee-based IoT. The purpose of this experiment’s results is for reference in developing an Intrusion Detection System (IDS) specifically for ZigBee-based IoT
ANOMALY DETECTION IN ZIGBEE-BASED IOT USING SECURE AND EFFICIENT DATA COLLECTION
This article outlines various techniques for detecting types of attacks that may arise in ZigBee-based IoT system. The researchers introduced a hybrid Intrusion Detection System (IDS), combining rule-based intrusion detection and machine learning-based anomaly detection. Rule-based attack detection techniques are used to provide an accurate detection method for known attacks. However, determining accurate detection rules requires significant human effort that is susceptible to error. If it is done incorrectly, it can result in false alarms. Therefore, to alleviate this potential problem, the system is being upgraded by combining it (hybrid) with machine learning-based anomaly detection. This article expounds the researchers’ IDS implementation covering a wide variety of detection techniques to detect both known attacks and potential new types of attacks in ZigBee-based IoT system. Furthermore, a safe and efficient meth-od for large-scale IDS data collection is introduced to provide a trusted reporting mechanism that can operate on the stringent IoT resource requirements appropriate to today's IoT systems
Making women’s voices count – what does the move from “more” to “meaningful” participation look like in peace negotiations?
The move from “more” to “meaningful” participation is urgently needed – not only in peacekeeping operations, but across the international efforts to build and sustain peace, including – crucially – peace negotiations. In this piece, Agnieszka Fal-Dutra Santos demonstrates what such a move might practically look like in the context of a peace process
INTRUSION DETECTION SYSTEM FOR ZIGBEE-BASED IOT USING DATA ANALYSIS RULES
The market for Internet of Things (IoT) products and services has grown rapidly. It has been predicted that the deployment of these IoT applications will grow exponentially in the near future. However, the rapid growth of IoT brings new security risks and potentially opens new types of attacks for systems and networks. This article outlines various techniques for detecting known attacks in ZigBee-based IoT systems. We introduced an Detection System (IDS) specific for ZigBee using data analytics method, that are used to provide an accurate detection method for known attacks. This article looks at our IDS implementation covering a wide variety of detection techniques to detect known attacks ZigBee IoT systems
Giant magnetoimpedance: new electrochemical option to monitor surface effects?
Magnetoimpedance, MI, change due to surface modification of the sensitive
element caused by biofluids was studied with the aim of creating a robust
sensor capable of separating the chemical surface modification from the sensing
process. A MI sensor prototype with an as-quenched FeCoSiB amorphous ribbon
sensitive element was designed and calibrated for a frequency range of 0.5 to
10 MHz at an intensity of the current of 60 mA. Measurements as a function of
the exposure time were made, first, in a regime where chemical surface
modification and sensing were separated and then, in a regime where they were
not separated (in a bath for fluids). The MI variation was explained by the
change of the surface magnetic anisotropy. It was shown that the
magnetoimpedance effect can be successfully employed as a new electrochemical
option to probe the electric features of surface-modified magnetic electrodes
when the biofluid, the material of the sensitive element, and the detection
conditions are properly selected and synergetically adjusted.Comment: 22 pages, 6 figure
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