Sharif Digital Repository

Uptake rate of 133Cs, at three different concentrations of CsCl, by Calendula alata, Amaranthus chlorostachys and Chenopodium album plants grown outdoors was studied. These plants grow abundantly in semi-arid regions and their varieties exist in many parts of the world. When exposed to lowest Cs concentration 68 percent Cs was remediated by Chenopodium album. 133Cs accumulation in shoots of Amaranthus chlorostachys reached its highest value of 2146.2mgkg -1 at a 133Cs supply level of 3.95mgl -1 of feed solution. The highest concentration ratio value was 4.89 for Amaranthus chlorostachys, whereas for the other tests it ranged from 0.74 to 3.33. Furthermore uptake of 133Cs by all three species... 

A simple process for the chemical vapor deposition of ultra SD single-wall carbon nanotubes has been developed. In this process, an iron nitrate nonahydrate solution in isopropyl alcohol with a concentration of (400 μgr/milt) was used to catalyst nanoparticle formation on an oxidized silicon wafer. The oxide on the substrate was made of a thick layer of wet oxide sandwiched between two thin layers of dry oxide. The process results in semiconducting Single-Walled carbon Nano Tubes (SWNTs) with diameters of less than 0.7 nm and more than a 1 ev band gap energy, which are amongst the smallest diameters of SWNTs ever reported. © Sharif University of Technology, June 2009  

In this research, a numerical investigation is done on the effect of employing the new combined vortex generators, the twisted tape turbulator and Al2O3-H2O nanofluid as the involved base fluid. Such study is carried out on the behavior of the heat transfer rate and the pressure drop of a double pipe heat exchanger. Accordingly, the response surface methodology (RSM) grounded on the central composite design (CCD) is used for acquiring the optimized geometry of the combined vortex generator and twisted tape turbulator. In order to have the maximum Nusselt number and minimum friction factor, twenty cases with different pitches ratio Pil=0.09-0.18, angles (θ=0-30°) and Reynolds numbers (Re =... 

Urban air quality is a major concern throughout the world. The concentration of human activities in a relatively small area puts enormous pressure on urban systems and has led to numerous environmental problems which have created major problems for urban air quality management. The complex nature of air pollution, especially with respect to health impacts in urban areas, has prompted attempts to define the so-called indicators that condense and simplify the available monitoring data to make them suitable for public reporting and decision makers. Several concepts and indicators exist to measure and rank urban areas in terms of their infrastructural, socioeconomic and environment-related... 

The climate change and human development in lake catchments have put these habitats in drying conditions, e.g. Aral Sea in Asia, Lake Chad in Africa, Lake Mead in USA, Lake Urmia in Iran, etc. These ecosystems play an important role in social, ecological, and economic activities. Lake Urmia, recognized as an international wetland in 1973 and located in Iran, which is the second largest hypersaline lake in the world, is in the same state. Lake Urmia biologically and ecologically is one of the most interesting places in the world. This lake is a habitat for various species. The lake's surface has shrunken from 6000 km2 to 900 km2 in 2013. The statistics indicate that the population has... 

In this letter, a new molecular modulation scheme for nanonetworks is proposed. To evaluate the scheme, a system model based on the Poisson distribution is introduced. The error probability of the proposed scheme as well as that of two previously known schemes, the concentration and molecular shift keying modulations, are derived for the Poisson model by taking into account the error propagation effect of previously decoded symbols. The proposed scheme is shown to outperform the previously introduced schemes. This is due to the fact that the decoding of the current symbol in the proposed scheme does not encounter propagation of error, as the decoding of the current symbol does not depend on... 

In diffusion-based molecular communication (DMC), a transmitter nanomachine is responsible for signal modulation. Thereby, the transmitter has to be able to control the release of the signaling molecules employed for representing the transmitted information. In nature, an important class of control mechanisms for releasing molecules from cells utilizes ion channels which are pore-forming proteins across the cell membrane. The opening and closing of the ion channels is controlled by a gating parameter. In this paper, an ion channel based modulator for DMC is proposed which controls the rate of molecule release from the transmitter by modulating a gating parameter signal. Exploiting the... 

Public participation is counted as one of the main indexes in sustainable urban management. Based on their nature, metropolitan cities has several and complex problems. For this purpose Tehran metropolitan area is selected. Quantitative Strategic Planning Matrix (QSPM) weighted through a made-byresearcher questionnaire. The reliability of the model was verified by Cronbach’s alpha coefficient. Evaluation matrix for internal and external factors was equal to 1.944 and 3.413, respectively. The strategies were classified and prioritize by quantitative matrix. Suitable strategies for Tehran city are as follows: developing a strategic plan in field of social control participatory management for... 

Today, managing an organization is concerned with many problems. Adopting proper strategies can promote an organization's survival. This study aimed at developing an appropriate HSSE Strategy for regional operation associated companies of Iran National Gas Company (INGS) using SWOT analysis. The analysis of the strengths, weaknesses, opportunities, and threats of HSSE was carried out and according to the results suitable strategies were recommended. In this regard, senior and junior managers, supervisors, and experts active in regional operation associated companies of Iran National Gas Company participated in SWOT analysis from HSSE angle. Then, they selected the most applicable SWOT... 

Abnormality detection and localization (ADL) have been studied widely in wireless sensor networks (WSNs) literature, where the sensors use electromagnetic waves for communication. Molecular communication (MC) has been introduced as an alternative approach for ADL in particular areas such as healthcare, being able to tackle the shortcomings of conventional WSNs, such as invasiveness, bio-incompatibility, and high energy consumption. In this paper, we introduce a general framework for MC-based ADL, which consists of multiple tiers for sensing the abnormality and communication between different agents, including the sensors, the fusion center (FC), the gateway (GW), and the external node (e.g.,... 

In diffusive molecular communication (DMC), the transmitter has to be able to control the release of signaling molecules for modulation of the information bits. In natural cells, pumping ions is an important control mechanism for releasing molecules which is carried out by ion pumps embedded in the membrane. The activity of the ion pumps is controlled by a driving parameter. In particular, light driven pumps are controlled by light intensity and enable a high degree of spatial and temporal control for modulation functionality. In this paper, a modulator based on ion pumps is proposed for DMC which controls the release rate of the molecules from the transmitter by modulating a light intensity... 

Bacterial populations are promising candidates for the development of the receiver and transmitter nanomachines for molecular communication (MC). A bacterial receiver is required to uptake the information molecules and produce the detectable molecules following a regulation mechanism. We have constructed a novel bacterial MC receiver using an inducible bacterial L-rhamnose-regulating operon. The proposed bacterial receiver produces green fluorescent protein (GFP) in response to the L-rhamnose information molecules following a quite fast regulation mechanism. To fabricate the receiver, the bacterial population has been transformed using a plasmid harboring L-rhamnose operon genes and gene... 

The macro-scale molecular communication (MC) recently received considerable attention because of its potential applications. Since most of the experimental research in MC focuses on the micro-scale cases, it is necessary to study and implement experiments to investigate the concept’s feasibility as well as to validate the models and parameters. In this paper, a macro-scale flow-based MC platform with fluidic medium is developed, in a semi-cylindrical channel with laminar flow condition. The transmission medium we consider is water in the plexi pipe, a transmitter releases Hydrochloric acid molecules into this pipe and a chemical sensor is used as the receiver. We propose an LTI model for the... 

Secure routing is a major key to service maintenance in ad hoc networks. Ad hoc nature exposes the network to several types of node misbehavior or attacks. As a result of the resource limitations in such networks nodes may have a tendency to behave selfishly. Selfish behavior can have drastic impacts on network performance. We have proposed a Misbehavior-Tolerant Multipath Routing protocol (MTMR) which detects and punishes all types of misbehavior such as selfish behavior, wormhole, sinkhole and grey-hole attacks. The protocol utilizes a proactive approach to enforce cooperation. In addition, it uses a novel data redirection method to mitigate the impact of node misbehavior on network...