Sharif Digital Repository

During a Wet End break, the loss of paper feed through the paper machine causes loss of sensory information and the remaining parts of the process are operated in open-loop. This causes the stock composition in the Headbox to deviate substantially from the nominal specifications, causing paper quality (after start up) and paper machine runability issues. In this work, the Base Sheet Ash measurement of the scanner is estimated using a least absolute value (LAV) model which can then be used for control of the chalk valve during the breaks to keep the Headbox Ash within specified limits. The model is computed using a very fast optimization algorithm which is able to compute the LAV solution... 

Since their introduction, paper-based microfluidic analytical devices (μPADs) have been ubiquitously utilized for different applications. The spontaneous imbibition of liquids in the paper-based devices that eliminates the requirement of an external pumping system has played a primary role in making paper an appropriate alternative for many other materials in the fabrication of microfluidic devices. Wax patterning is one of the most common methods to fabricate μPADs. Dynamics of the flow in channels with wax boundaries deviate from Washburn's law. Despite some research performed to model the effects of wax boundaries, some gaps remain in the presented models. A more general model is needed... 

Multi-layer schemes have been proposed for steganography. Also some authors have combined these methods with the idea of wet paper codes and gained higher embedding efficiency. This paper proposes a generalized multi-layer method for wet paper embedding. First, the cover bits are divided into blocks and, by combining these bits in groups of 3, a pyramid is formed. Next, the secret message is embedded through a layer-by-layer procedure. The proposed method has higher embedding efficiency in some cases and provides more flexibility for choosing the embedding payload, especially in lower payload conditions  

'Three-link-model' Exergoeconomic methodology optimises the design and operability of a system. Contrary to traditional iterative Exergoeconomic optimisation methods, a reversed method is used, since assumptions considered by Tsatsaronis for calculating cost-optimal Exergetic efficiency and relative cost difference, were not applicable, new assumptions have been adopted. In a case study applied to Mazandaran paper industry, iterative reversed optimisation results have been compared with evolutionary programming results. Replacement of Pressure Valve and Direct Cyclone Contact Evaporation is proposed, while by selection of the optimum decision variable, recoverable black liquor is increased... 

In this paper, the Two-Way Channel (TWC) with noncausal Channel State Information (CSI) is investigated. For the discrete memoryless channel an achievable rate region is derived. Then by extending the result to the Gaussian TWC with additive interference noise, it is shown that the capacity region of the latter channel is the same as the capacity when there is no interference, i.e., a two-way version of Costa's writing on dirty paper problem is established  

By simultaneously applying pinch technology and the exergoeconomic method to a complex process system, beneficial and energy-efficient measures are identified. The "three-link-model" exergoeconomic methodology optimizes the design and operability of a system. In this work, contrary to traditional exergoeconomic methods, a reversed method is used. The approach proposed for the optimization of such a complex system is to iteratively optimize subsystems. Since the reversed exergoeconomic method is used, assumptions considered by Tsatsaronis (based on four assumptions for calculating the cost-optimal exergetic efficiency and relative cost difference) are not applicable and new assumptions are to... 

Recycling of wastepaper is an effective way to achieve the sustainable paper manufacturing regarding sustainable development goals. Focusing on the mixed wastepaper sorting, recovery of suitable papers for deinking purpose and minimizing the impurities were developed in this study. In a wastepaper sorting process, each equipment has its own role in increasing recycling performance. In this study, disc screen was applied and evaluated for sorting of the mixed wastepaper considering independent variables such as inclination, velocity and moisture content. Response surface method was applied for design of the experiments. Sorting efficiency of 100% was achieved in two conditions: 1–20%... 

A family of matrix embedding steganographic schemes for digital images is investigated. The target schemes are applied to blocks of n pixels in a cover image. In every block, at most m pixels are allowed to change with q-ary steps. We have derived some upper bounds on the embedding efficiency of these schemes for different values on m. It is also shown that these upper bounds approach the general upper bound on the embedding efficiency of q-ary steganography. For the case of q=3, we have shown that there is no feasible optimum member of the family for m=2, although for m=1, a well-known example exists. Instead, for m=2, a new close-to-bound scheme in the family is presented which exploits... 

Gasification of black liquor is an alternative recovery technology. Pulp and paper industries are turning their attention to black liquor gasification as a replacement for recovery boilers. Gasification-combined cycle exergoeconomic analyses have been used to study the economical and exergetical performance of black liquor. Both conventional iterative exergoeconomic optimization and multi objective evolutionary optimization have been applied. The iterative optimization results have been compared with evolutionary programming results in order to evaluate the accuracy. The strength of proposed optimization methods are elucidated in a case study applied to Mazandaran Wood and Paper Industries... 

A triboelectric nanogenerator (TENG) electrode sensitive to the adsorption of water molecules has been introduced to create a self-powered humidity sensor. Graphene oxide (GO) nanosheets and graphene oxide nanoribbon (GONR) possessing oxygenated functional groups, as well as high dielectric constants, have been proposed as appropriate candidates for this purpose. GO papers have been fabricated in three forms, i.e. pure GO paper, uniform composites of GONR and GO, and double-layer structures of GONR on top of GO. Results showed that all of the prepared paper-based TENGs revealed excellent performances by maximum output voltage above 300 V. As active humidity sensors, the maximum voltage... 

Thermal neutron analysis (TNA) technology has been used for the non-destructive detection of explosives. The system uses a relatively weak 252Cf neutron source (1.03.107 n/s) and two 3″3×″ NaI(Tl) detectors. The presence of explosives is confirmed via detection of the 10.83 MeV prompt gamma-ray associated with nitrogen decay. The MCNP4A code was used to simulate the neutron and gamma transport through the system. The thermal neutron flux in the activation position was measured using gold and indium foils. The measured thermal neutron flux was lower, by not more than 9.5%, than that of simulation. In this report the results of the preliminary tests on the system are described  

In this paper, we propose a novel method for academic assessment inspired by the decentralized applications made possible by blockchain technology. The proposed method applies to a wide range of academic material, including assignments, exams, academic papers, etc and tackles issues regarding potential personal bias and makes assessment possible without the need to rely on a few assessors. We examine the challenges and possibilities that arise with this method and further explore more general applications in areas such as education. In the experiments conducted for this research, poll results show generally positive views toward the fairness of this system compared to the traditional... 

In this study, a transformer model is proposed to simulate the behaviour of a real transformer, under presence ofdifferent types of defects which contribute to partial discharge (PD) generation, as closely as possible. Five different typesof defects (scratch on winding insulation, bubble in oil, moisture in insulation paper, very small free metal particle intransformer tank and fixed sharp metal point on transformer tank) are implemented artificially into these transformermodels to investigate the resultant PD current signal magnitude and characteristics. Time-domain PD currentwaveforms are recorded on those transformer models which have one type of those defects. The resultant statisticalPD... 

Exergoeconomic Composite Curves (EECC) - a synergy of Exergoeconomic and Composite Curves of Pinch Analysis is a novel method and propounded for the first time in this Paper. This is the first attempt to represent investment and annual operating and maintenance costs in addition to Exergy in a graphical form similar to Composite Curves. In this Paper a simplified methodology that represents the Exergy of chemical units of a process in a graphical form and preliminary investment strategy is developed for use with the EECC. The object has therefore been to study the possibilities to save money in Northern Pulp and Paper Mill, an Iranian mill with a capacity of 600 tons/day  

Recycling of wastepaper is an effective way to achieve the sustainable paper manufacturing regarding sustainable development goals. Focusing on the mixed wastepaper sorting, recovery of suitable papers for deinking purpose and minimizing the impurities were developed in this study. In a wastepaper sorting process, each equipment has its own role in increasing recycling performance. In this study, disc screen was applied and evaluated for sorting of the mixed wastepaper considering independent variables such as inclination, velocity and moisture content. Response surface method was applied for design of the experiments. Sorting efficiency of 100% was achieved in two conditions: 1–20%... 

The special issue of the Journal of Supercomputers presents recent research results on multicore systems where contributions cover different topics such as architecture, programming tools and applications, as well as other related aspects of multicore systems design. Contributed papers include some of the high-quality papers accepted at the CADS 2013 conference that took place in Tehran, which were selected based on the evaluation scores and presentation quality at the conference. The review process required three rounds of diligent reviews and revisions resulting in the final accepted manuscripts for publication in the journal  

Herein, a series of superhydrophobic thin polyacrylic resin-coated carbon black (CB)/hexagonal boron nitride (h-BN)@Fe3O4/cellulose composite papers with good flexibility, low density (~0.67 g/cm3), high electrical conductivity (~0.065 S/cm), good thermal conductivity (0.462 W.m−1. K−1), and with water contact angle (WCA) of 153° were successfully fabricated by a facile dip-coating/spraying method. The CB-BN@Fe3O4 distribution in cellulose matrix provided high electrical conductivity in the in-plane and thickness directions. The electrical conductivity in both in-plane and thickness directions increased by increasing the number of vacuum-assisted dip-coating cycles. Moreover, these... 

Here, we report 3D hierarchical SnO2 nanowire (NW) core-amorphous silicon shell on free-standing carbon nanotube paper (SnO2@a-Si/CNT paper) as an effective anode for flexible lithium-ion battery (LIB) application. This binder-free electrode exhibits a high initial discharge capacity of 3020 mAh g-1 with a large reversible charge capacity of 1250 mAh g-1 at a current density of 250 mA g-1. Compared to other SnO2 NW or its core-shell nanostructured anodes, the fabricated SnO2@a-Si/CNT structure demonstrates an outstanding performance with high mass loading (∼5.9 mg cm-2), high areal capacity (∼5.2 mAh cm-2), and large volumetric capacity (∼1750 mAh cm-3) after 25 cycles. Due to the...