Sharif Digital Repository

Several corrosion inhibitors, such as, HEDP, sodium molybdate and zinc ions, were added to an aqueous corrosive media containing different concentrations chloride ions, and the corrosion rates (CRs) of carbon steel were measured at various temperatures. It was shown that, in the presence of more than 1,200 ppm of chloride ions, and temperatures greater than or equal to 42.5°C, the combination of HEDP, molybdate and zinc could not control the corrosion in a cooling water system. Then four different models were designed to represent the CR of carbon steel in presence of various corrosive parameters  

One of the foremost challenges in modulation scheme for molecular communication is positivity of the transmission signal (only a positive concentration of molecules can be released in the environment). This restriction makes handling of the InterSymbol Interference (ISI) a challenge for molecular communication. In this paper, a novel modulation is proposed which introduces use of negative signals to ameliorate the transmission link performance. A precoder scheme based on the diffusion channel model is proposed and shown to have a significant improvement compared to previous modulation schemes such as CSK and MCSK  

While ISI is a common issue in classical communications, it is more challenging and prominent in the context of molecular communication, because one cannot readily combat ISI with classical channel equalization techniques. This is due to the fact that transmitter can only release a positive amount of concentration of a specific molecule into the medium. Previous works have proposed use of chemical reactions to remove molecules from the environment, and to effectively simulate negative signals. However, the differential equation describing a diffusion-reaction process is non-linear. This precludes the possibility of using Fourier transform tools. In this paper, a solution for simulating... 

Nanonetworking indicates new solutions for many applications in biomedical and industrial fields. In this paper, we examine the diffusion-based molecular communication for information transmission in nano-networks. Design of practical decoders for resource-limited nano-networks requires an understanding the fundamental performance limits of memory-limited decoders. While some existing works in the literature do consider decoders with limited memory, to best of our knowledge, the tradeoff between memory and probability of error has not been studied in the literature. In this paper we make a first step by studying this tradeoff for a particular molecular communication channel between two... 

In this paper, a diffusion-based molecular communication channel between two nano-machines is considered. The effect of the amount of memory on performance is characterized, and a simple memory-limited decoder is proposed; its performance is shown to be close to that of the best possible decoder (without any restrictions on the computational complexity or its functional form), using genie-aided upper bounds. This effect is adapted to the case of Molecular Concentration Shift Keying; it is shown that a four-bit memory achieves nearly the same performance as infinite memory for all of the examples considered. A general class of threshold decoders is considered and shown to be suboptimal for a... 

We use the direct simulation Monte Carlo (DSMC) method and investigate the subsonic rarefied gas flow through micro/nanochannels, imposing a constant pressure ratio and a constant temperature difference between the inflow and wall temperature. We further study the heat transfer characteristics of subsonic nitrogen gas flow under this imposed temperature difference. We show that, specifying a higher temperature magnitude would lead to more rarefactions even imposing a fixed temperature difference. This consequently results in a higher wall heat flux rate for a fixed inflow-wall temperature difference. Our investigating shows that the number of simulated particles need to increase suitably if... 

In this paper, we consider abnormality detection via diffusive molecular communications (MCs) for a network consisting of several sensors and a fusion center (FC). If a sensor detects an abnormality, it injects a number of molecules into the medium which is proportional to its sensing output. Two transmission schemes for releasing molecules into the medium are considered. In the first scheme, each sensor releases a different type of molecule (DTM), whereas in the second scheme, all sensors release the same type of molecule (STM). The molecules released by the sensors propagate through the MC channel and some may reach the FC where the final decision regarding whether or not an abnormality... 

In this paper, we propose using mobile nanosensors (MNSs) for early stage anomaly detection. For concreteness, we focus on the detection of cancer cells located in a particular region of a blood vessel. These cancer cells produce and emit special molecules, so-called biomarkers, which are symptomatic for the presence of anomaly, into the cardiovascular system. Detection of cancer biomarkers with conventional blood tests is difficult in the early stages of a cancer due to the very low concentration of the biomarkers in the samples taken. However, close to the cancer cells, the concentration of the cancer biomarkers is high. Hence, detection is possible if a sensor with the ability to detect... 

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... 

This book focuses on a central question in the field of complex systems: Given a fluctuating (in time or space), uni- or multi-variant sequentially measured set of experimental data (even noisy data), how should one analyse non-parametrically the data, assess underlying trends, uncover characteristics of the fluctuations (including diffusion and jump contributions), and construct a stochastic evolution equation?
Here, the term "non-parametrically" exemplifies that all the functions and parameters of the constructed stochastic evolution equation can be determined directly from the measured data.
The book provides an overview of methods that have been developed for the analysis of... 

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...