Design and analysis of a novel low PDP full adder cell

This paper, presents a new full-swing low power high performance full adder circuit in CMOS technology. It benefits from a full swing XOR-XNOR module with no feedback transistors, which decreases delay and power consumption. In addition, high driving capability of COUT module and low PDP design of SUM module contribute to more PDP reduction in cascaded mode. In order to have accurate analysis, the new circuit along with several well-known full adders from literature have been modeled and compared with CADENCE. Comparison consists of power consumption, performance, PDP, and area. Results show that there are improvements in both power consumption and performance. This design trades area with low PDP

Channel conductance of ABA stacking trilayer graphene nanoribbon field-effect transistor

In this paper, our focus is on ABA trilayer graphene nanoribbon (TGN), in which the middle layer is horizontally shifted from the top and bottom layers. The conductance model of TGN as a FET channel is presented based on Landauer formula. Besides the good reported agreement with experimental study lending support to our model, the presented model demonstrates that minimum conductivity increases dramatically by temperature. It also draws parallels between TGN and bilayer graphene nanoribbon, in which similar thermal behavior is observed. Maxwell-Boltzmann approximation is employed to form the conductance of TGN near the neutrality point. Analytical model in degenerate regime in comparison with reported data proves that TGN-based transistor will operate in degenerate regime like what we expect in conventional semiconductors. Moreover, our model confirms that in similar condition, the conductivity of TGN is less than bilayer graphene nanoribbon as reported in some experiments

A model for length of saturation velocity region in double-gate graphene nanoribbon transistors

Length of saturation region (LVSR) as an important parameter in nanoscale devices, which controls the drain breakdown voltage is in our focus. This paper presents three models for surface potential, surface electric field and LVSR in double-gate Graphene nanoribbon transistors. The Poisson equation is used to derive surface potential, lateral electric field and LVSR. Using the proposed models, the effect of several parameters such as drain-source voltage, oxide thickness, doping concentration and channel length on the LVSR is studied

A new GIS-based model for automated extraction of Sand Dune encroachment case study: Dakhla Oases, western desert of Egypt

The movements of the sand dunes are considered as a threat for roads, irrigation networks, water resources, urban areas, agriculture and infrastructures. The main objectives of this study are to develop a new GIS-based model for automated extraction of sand dune encroachment using remote sensing data and to assess the rate of sand dune movement. To monitor and assess the movements of sand dunes in Dakhla oases area, multi-temporal satellite images and a GIS-developed model, using Python script in Arc GIS, were used. The satellite images (SPOT images, 1995 and 2007) were geo-rectified using Erdas Imagine. Image subtraction was performed using spatial analyst in Arc GIS, the result of image subtraction obtains the sand dune movement between the two dates. The raster and vector shape of sand dune migration was automatically extracted using spatial analyst tools. The frontiers of individual dunes were measured at different dates and movement rates were analyzed in GIS. The ModelBuilder in Arc GIS was used in order to create a user friendly tool. The custom built model window is easy to handle by any user who wishes to adapt the model in his work. It was found that the rate of sand dune movement ranged between 3 and 9 m per year. The majority of sand dunes have a rate movement between 0 and 6 m and very few dunes had a movement rate between 6 and 9 m. Integrating remote sensing and GIS provided the necessary information for determining the minimum, maximum, mean, rate and area of sand dune migration

Determining the Optimal Cropping Pattern Based on the Multiple Objectives of Water, Energy, Food and Economic Profit Indices (Case Study: Markazi Province - Farahan Plain)

Introduction Water is one of the most important factors of development in human societies, water scarcity, specially fresh water which is one of the main limitation for agricultural, economic and social development in most developing countries. Providing and implementing an optimal cropping pattern, in addition to better management of water and soil resources, can lead to reducing production risk, increasing the ability to deal with crises, improving employment, better management of providing services to farmers, and providing the possibility of expanding agro-based industries. In many regions of the world, including in Iran, many studies have been done to improve the cropping pattern in different regions. Despite the existing problems in designing and implementing the appropriate cropping pattern in the plains, modifying the cropping pattern based on scientific principles and emphasizing the reduction of water consumption while reducing water consumption provides the possibility of sustainable agriculture and in terms of economic and social aspects. Implementing an optimized cropping pattern in the Farahan Plain is an undeniable necessity to preserve national resources. This study was conducted with the objective of optimizing the cropping pattern in the area, taking into account multiple criteria.   Methodology In this research, considering the importance of determining the cropping pattern based on the multiple objectives of the decision makers, it was tried to determine the optimal cropping pattern by using mathematical programming and fuzzy logic by establishing a compromise between the objectives of the cropping pattern. The model considered for this study was in the framework of the goal of the maximum ideal distance (Fuzzy Composite Distance). Also, in order to use water resources sustainably, scenarios of cropping patterns are presented based on different conditions of water resources uses. Based on the basin's water resource stability, an optimal cropping pattern was developed to address the conditions of normal water resource exploitation, as well as sustainable and unsustainable scenarios. Each scenario corresponds to a specific period. To achieve this, a multi-objective planning approach was utilized, integrating water, food, energy, and economic profit indicators. The resulting optimal cropping pattern considers stable water resource utilization during normal, drought, and wet periods, ensuring sustainable conditions.   Results and Discussion The results showed that the amount of water consumed by the optimal cropping pattern compared to the existing cropping pattern under normal, drought and wet conditions is reduced by 23.2, 29.2 and 18.1%, respectively. On the other hand, compared to the existing cropping pattern, the amount of calories produced by the optimal cropping pattern under normal, drought and wet conditions increases by 51.7, 61.9 and 45.2%, the average energy efficiency increases by 40.9, 42.8 and 35.8% and the net profit productivity increases by 43.3, 30.9 and 44.2 %, respectively. Based on the obtained results, it can be seen that in the optimal cropping pattern in drought conditions, the cultivated area of crops such as potatoes, onions, tomatoes, grain corn, sugar beets, beans, alfalfa and watermelons should reach to the zero or be at the lowest possible level. In normal and drought conditions, the cultivated area of these crops should be minimal. On the other hand, the area under cultivation of crops such as fodder sorghum, fodder corn, saffron, cumin, camellia and medicinal plants should be increased and the cultivation of these crops should be promoted at the region. Also, regarding horticultural products, the cultivated area of walnut, apple, peach, apricot and almond orchards should be minimized and replaced with plants such as grapes, oleaster, jujube, barberry, rose, and figs. Conclusion Based on the obtained results, it was found that the use of the optimal cropping pattern derived from the indicators of water, food, energy and economic profit is completely superior and preferred over the existing cropping pattern and single purpose optimal cropping pattern. In order to achieve sustainable water resource management, it is recommended to modify the cropping pattern during drought, normal, and wet periods based on the suggested optimal cropping pattern. The existing cropping pattern currently falls short in terms of achieving the four objectives of water, food, energy, and economic profit. Therefore, it is crucial to develop main plans and strategies in the Farahan Plain that align with the implementation of the proposed optimal cropping pattern. By doing so, it will be possible to optimize the allocation of water resources and achieve improved outcomes in terms of water availability, food production, energy efficiency, and economic profitability

Quantum confinement effect on trilayer graphene nanoribbon carrier concentration

In this study, one-dimensional vision of carrier movement based on the band structure of trilayer graphene nanoribbon in the presence of a perpendicular electric field is employed. An analytical model of ABA-stacked trilayer graphene nanoribbon carrier statistics as a fundamental parameter of field effect transistor (FET) in corporation with a numerical solution is presented in the degenerate and non-degenerate limits. The simulated results based on the presented model indicate that the model can be approximated by degenerate and non-degenerate approximations in some numbers of normalised Fermi energy. Analytical model specifies that carrier concentration in degenerate limit is strongly independent of normalised Fermi energy; however, in the non-degenerate limit, it is a strong function of normalised Fermi energy. The proposed model is then compared with other types of graphene. As a result, the developed model can assist in comprehending experiments involving trilayer graphene nanoribbon FET-based devices

A New Hybrid Highly Sensitive Optical Humidity Sensor

An approach is presented to make new waveguide-based sensors aiming to improve the sensitivity. In this approach, the sensor benefits from both optical and electrical properties of the coated material on the waveguide. The approach was applied on graphene oxide for purpose of humidity sensing. The results show that the sensitivity is improved between 3% to 85% compared to optical device and 131% to 3600% compared to electrical device. More importantly, the new device shows at least 176% sensitivity at the whole range of relative humidity compared to 102% for an optical device. In addition, its fabrication process is fast, cheap and simple and the response and recovery times are very low, around 0.45 and 0.74 seconds respectively