Search

Precise knowledge of the soil organic carbon (SOC) stocks under various land uses is needed to meet the Kyoto Protocol and for the sustainability of natural resources. The purpose of the present st...

The current study aims at forming new prediction models to be employed in the approximating the possible uptake of a range of 10 heavy metals (HMs) (Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb and Zn) by Hordeum vulgare tissues including roots, shoots and grains following its growth in soil amended with sewage sludge (SS) using conditions employed in greenhouses. The present study determined an insignificant difference between the actual and predicted quantities of the HMs in the three tissues using t values. The majority of the predicted quantities of the HMs were acceptable with the exception of Cd in the shoots, Cu in grains and Pb in roots. Consequently, it is possible to use these models in assessing the cultivation of barley plants in soil amended with SS in a safe way, while simultaneously monitoring any potential risks to the health of humans.

A two-stage ORC (Organic Rankine Cycle) is being proposed for the recovery and utilization of low-grade heat from single flash geothermal power plant exhaust flue fluids. The working fluids for two-stage the recovery system are R227ea and R116. The impact of essential design parameters such as inlet temperature of the cycle, ambient temperature, geothermal turbine inlet pressure, geothermal condensation temperature on system performance are investigated using thermodynamic mathematical models regarding energy and exergy efficiencies as the objective function. The addition of the recovery section to the base cycle improves the thermal efficiency from 0.2023 to 0.2178, a 7.66% improvement in this critical metric. Furthermore, the exergy efficiency rises from 0.55044 to 0.5803, representing a 15.04% boost in exergy efficiency. Furthermore, the system's overall output rises from 7690 kW to 9898 kW, representing a substantial gain of 28.71%. The suggested recovery system's cycle has a lower LEC than a single flash geothermal cycle from an economic standpoint. LEC Reduced from $ 0.125 per kilowatt to $ 0.108 per kw, a cost savings. As a result, including a recovery section in the basic single flash geothermal cycle will significantly improve system performance.

Nowadays, because of the energy crisis, combined heat and power systems have notable benefits. One of the best devices is SOFC (Solid Oxide Fuel Cell) which joins heat and power frameworks. Some considerable failure modes arise that can affect these devices’ productivity. Generally, failure modes evaluations need an experts team to achieve uncertainties belongs to the risk assessment procedure. To improve the efficiency of the routine FMEA methodology and to represent a suitable hybrid fuzzy MCDM approach for FMEA, in this work, fully fuzzy best-worst method (FF-BWM) is employed to achieve the risk factors weights then fuzzy weighted aggregated sum product assessment (F-WASPAS) approach to detect the failure modes priorities is utilized. Ultimately, the sensitivity analyses demonstrate that the offered framework is verified and can make applicable data in risk management decision-making evaluation.

Ground source heat pump, due to high coefficient of performance (COP) and use of low-temperature thermal energy source, is one of the best technologies to use renewable energy resources. In this work, at first, a geothermal heat pump for heating with an economizer is simulated, and then the effects of the variations in different parameters such as evaporator pressure, condensation pressure, and intermediate pressure on heat pump and total COP and exergy efficiency are analyzed. Initially, the thermodynamic simulation of the system is performed for different working fluids (R134a, R-12, R152a, R1234yf, and R1234ze(E)) in the EES software programming environment. The COP and exergy efficiency are calculated for different working fluids and obtained optimal values. The best overall coefficient of performance of the system is related to fluid R134a with a value of 3.663 and the best overall exergy efficiency of the system is related to fluid R1234ze(E) with a value of 0.5517. The lowest PCEU value is for fluid R152a with 0.01247$ per kilowatt. It can be concluded that by reducing the evaporator pressure of the cycle, the cost of producing an energy unit will be cheaper and by reducing the middle pressure of the cycle, the cost of producing an energy unit will be more expensive.

The increasing complexity and heterogeneity of avionic networks make resource savings a challenging task to guarantee easy incremental design during the long lifetime of an aircraft. In this paper, we focus on the optimization of interconnection devices for multi-cluster avionic networks, called Remote Data Concentrators (RDC), and especially for the CAN-AFDX network. The design of this optimized RDC device consists in implementing frame packing strategies to manage upstream (sensors) flows to improve bandwidth utilization in the AFDX; and Hierarchical Traffic Shaping (HTS) algorithm to control downstream (actuators) flows to guarantee bandwidth isolation on CAN. Schedulability analysis integrating the effects of these new mechanisms is detailed and validated. Furthermore, a heuristic approach to tune the Hierarchical Traffic Shaping parameters within the RDC device is proposed to reduce as much as possible bandwidth utilization in the AFDX, while ensuring flows schedulability. The performance analysis conducted on a realistic avionic case study proves the efficiency of the optimized RDC device to reduce bandwidth utilization in the AFDX, compared to the basic device currently implemented in avionics.

National audience; The increasing complexity and heterogeneity of avionics networks make resource optimization a challenging task. In contrast to many previous approaches pursuing the optimization of traffic-source mapping and backbone network analysis, our work presented herein mainly focuses on the optimization of interconnection devices for multi-cluster avionics networks. In this paper, we introduce an optimized interconnection device, integrating novel frame packing strategies and schedulability analysis to enhance the communications between an AFDX-like backbone network and various peripheral sensor/actuator networks in terms of resource savings. The performance analysis conducted on a representative avionics communication architecture highlights the efficiency of our proposal to save resources particularly consumed bandwidth. These latter is considered as an important feature for avionics applications to guarantee easy incremental design during the long lifetime of an aircraft.

The current avionics communication architecture has recently arisen some limitations for meeting the emerging requirements of new generation aircraft in terms of modularity, weight and integration costs. In order to cope with these limitations, an alternative avionics communication architecture based on a multi-cluster embedded network is proposed in this paper. The critical avionics subsystems still are interconnected via the backbone network AFDX, however the sensors and actuators are grouped to be interconnected via CAN buses, independently of the associated avionics subsystems. The obtained clusters will be interconnected via specific gateways to handle the heterogeneity between the AFDX and CAN buses. This paper focuses first on the relevant aspects of our proposal and the offered real time guarantees required by critical avionics applications. Then, since an efficient bandwidth consumption is inherently important to guarantee an easy incremental design process, an optimized gateway design with a new frame packing strategy is proposed and evaluated in our context.

WOPANets (WOrst case Performance Analysis of embedded Networks) is a design aided-decision tool for embedded networks. This tool offers an ergonomic interface to the designer to describe the network and the circulating traffic and embodies a static performance evaluation technique based on the Network Calculus theory combined to optimization analysis to support early system level design exploration for embedded networks. In this paper, we describe the features set of WOPANets tool and we provide analysis in the case of a realistic embedded avionic network to show how the variation of some system's parameters can improve the system performances to support the required constraints.