Sharif Digital Repository

Experiment is a procedure for verifying or establishing the validity of a hypothesis and then measuring or evaluating its outcomes. Due to the inherent uncertainties or ambiguities of its outcomes, a further treatment is needed for producing identical results. Fuzzy map is an approach for removing the uncertainties of the outcomes. In this manuscript, the procedure employed for conducting research and development in the field of nontechnology, in a developing country, is considered and the factors governing its success and its failures are analyzed. To accomplish this task, a thorough literature review was performed and the related critical factors were identified. Then an extensive survey... 

This paper presents a state of the art review of adsorption models for a new plant-based surfactant adsorption onto sandstone minerals. The adsorption data at both kinetic and equilibrium modes were obtained from batch experiments. Four adsorption kinetic models, five two-parameter, and six three-parameter equilibrium models were used for interpretation of the obtained data. Among the two and three-parameter isotherm models applied, the Jovanovic and the Khan isotherms showed the best fit, respectively. And the pseudo-second order model presented a better fit than other kinetic models. Finally, a computer-based modeling approach was developed and used for predicting the kinetics of... 

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  

In recent years, polyethylene glycol (PEG) has attracted special attention as a green and inexpensive solvent in various chemical transformations. The current critical review deals with breakthrough achievements for the applications of PEG as an alternative reaction media well-known coupling reactions such as Suzuki, Heck, Stille, Sonogashira, Hiyama and some challenging organic reactions for carbon-carbon bond formation  

The paucity of cellular and molecular signals essential for normal wound healing makes severe dermatological ulcers stubborn to heal. The novel strategies of skin regenerative treatments are focused on the development of biologically responsive scaffolds accompanied by cells and multiple biomolecules resembling structural and biochemical cues of the natural extracellular matrix (ECM). Electrospun nanofibrous scaffolds provide similar architecture to the ECM leading to enhancement of cell adhesion, proliferation, migration and neo tissue formation. This Review surveys the application of biocompatible natural, synthetic and composite polymers to fabricate electrospun scaffolds as skin... 

In this paper, we study the differences between the Centralized and Decentralized approaches in a two-echelon stochastic inventory system under the lost sale policy. We formulate the condition in which the retailer applies (r, Q) inventory policy, and his relation with the upper echelon who acts as a manufacturer. This situation has not been considered in the literature before. The Centralized approach results in optimal solution of the system and the Decentralized one is based on Stackelberg game in which the manufacturer is the leader. The demand arrives according to the stationary Poisson process. We drive the long-run average cost functions, then a set of computational steps are... 

Based on general "System Theory", a system when it comes to its intended operational life; must exhibits three distinguished phases of (1) Pre-mission, (2) Mission, and (3) Post-mission. During Pre-mission one evaluates the system elements readiness to conduct the mission; their proper configurations in addition to their support roles to conduct their organizational role. During Post-mission, we check whether our evaluations were in fact, correct to the levels expected. Both pre and post mission phases are necessary for a successful mission. An education system; especially designed for space applications which aims to deliver the necessary workforce for the relevant industries and other... 

This article deals with technology strategy and its linkage with overall strategy at multi-business, diversified groups. In the last two decades, the alignment of technology and business strategy has been one of the important research fields in strategy and technology management scopes. These researchs has been concentrated on single companies through which different frameworks, models & decision support tools have been developed and widely utilized by industries. Although multi-business and diversified groups play an important role in global and national economics and need a comprehensive and overall plan for the management of their diversified technological assets, there are few researchs... 

There are two main assumptions in multiperiodic inventory control problems. The first is the continuous review, where, depending on the inventory level, orders can happen at any time, and the other is the periodic review, where orders can only happen at the beginning of each period. In this paper, these assumptions are relaxed, and the periods between two replenishments are assumed independent and identically distributed random variables. Furthermore, the decision variables are assumed integer-type and that there are two kinds of space and budget constraints. The incremental discounts to purchase products are considered, and a combination of backorder and lost sales are taken into account... 

In this study, an inventory system consisting of a single product, one supplier, and multiple identical retailers is considered. Each retailer replenishes inventory from the supplier according to the well known (R,Q) policy. Transit times are constant and retailers face independent Poisson demand. The supplier utilizing the retailers' information in decision making for replenishment policy with a given order size starts with m initial batches (of size Q) and places an order in a batch of size Q to an outside source when a new order is placed. In this inventory system, excess demand is backordered, delayed orders are satisfied on a first-come first-serve basis, and no partial shipment is... 

Operational capabilities are used in resource based view in strategic management literature to explain how the difference in performing similar activities results in heterogeneity between firms. In order to advance our understanding of this concept, using a system metaphor, we try to shape a framework for micro-level analysis of operational capabilities. Following two stages of holism and focus for identifying system boundaries through looking related literatures, we propose knowledge, skills and tools as general micro elements of operational capabilities in form domain. Using Dependency Structure Matrix (DSM), we finally synthesize our conceptual framework to capture interactions of... 

A literature review of laboratory and field scale studies on low salinity water (LSW) injection showed that the salinity and composition of injected water can have a significant impact on oil recovery. Historically, extensive research has been completed to understand the mechanisms and factors affecting LSW injection. However, although numerous mechanisms have been proposed to describe the interactions in the target process, none have been widely accepted. In this study, waterflooding tests were used to investigate the advantages, disadvantages, and effect of LSW injection. In laboratory tests, two different brines and crude oil of one of Iran's southern reservoirs were used to assess the... 

Neural tissue engineering aims at developing novel approaches for the treatment of diseases of the nervous system, by providing a permissive environment for the growth and differentiation of neural cells. Three-dimensional (3D) cell culture systems provide a closer biomimetic environment, and promote better cell differentiation and improved cell function, than could be achieved by conventional two-dimensional (2D) culture systems. With the recent advances in the discovery and introduction of different types of stem cells for tissue engineering, microfluidic platforms have provided an improved microenvironment for the 3D-culture of stem cells. Microfluidic systems can provide more precise... 

In recent years miscellaneous smart micro/nanosystems that respond to various exogenous/endogenous stimuli including temperature, magnetic/electric field, mechanical force, ultrasound/light irradiation, redox potentials, and biomolecule concentration have been developed for targeted delivery and release of encapsulated therapeutic agents such as drugs, genes, proteins, and metal ions specifically at their required site of action. Owing to physiological differences between malignant and normal cells, or between tumors and normal tissues, pH-sensitive nanosystems represent promising smart delivery vehicles for transport and delivery of anticancer agents. Furthermore, pH-sensitive systems... 

Background: The use of knee-ankle-foot orthoses with drop locked knee joints produces some limitations for walking in subjects with quadriceps muscle weakness. The development of stance control orthoses can potentially improve their functionality. Objectives: The aim of this review was to compare the evidence of the effect of stance control orthoses to knee-ankle-foot orthoses with drop locked knee joints in improving kinematic variables and energy efficiency of walking by subjects with quadriceps muscle weakness caused by different pathologies. Study design: Literature review. Methods: Based on selected keywords and their composition, a search was performed in Google Scholar, PubMed,... 

Background: Foot orthoses are used to optimize lower extremity function and can improve postural stability by enhancing the afferent somatosensory feedback available to the central nervous system. Objective: The aim of this review was to evaluate the effect of foot orthoses on balance control in older subjects. Study design: Systematic review. Methods: The search strategy was based on the Population Intervention Comparison Outcome method. A search was performed in PubMed, Science Direct, Google Scholar, and ISI Web of Knowledge databases by using selected keywords. A total of 22 articles were selected for final evaluation. Results: The results demonstrated that older people should be advised... 

Electric power system and its components, most of which developed based on the rising electricity demand during economic growth periods of 1970s and 1980s, have aged and some are not being replaced quickly. In addition, the integration of variable sources of energy has changed the way assets are being managed for optimal operation. Aging assets and uncertainty in power system load profile and demand management create a challenge for the optimal operation and maintenance of the electricity grid. This special section aims at addressing the challenges and opportunities in deployment of smart grid technologies such as wireless sensors for condition monitoring and intelligent electronic devices... 

Nanotechnology could provide a new complementary approach to treat coronary artery disease (CAD) which is now one of the biggest killers in the Western world. The course of events, which leads to atherosclerosis and CAD, involves many biological factors and cellular disease processes which may be mitigated by therapeutic methods enhanced by nanotechnology. Nanoparticles can provide a variety of delivery systems for cargoes such as drugs and genes that can address many problems within the arteries. In order to improve the performance of current stents, nanotechnology provides different nanomaterial coatings, in addition to controlled-release nanocarriers, to prevent in-stent restenosis.... 

In this paper, a continuous review inventory system is considered in which an order in a batch of size Q is placed immediately after the inventory position reaches R. Transportation time is constant and demands are assumed to be generated by a stationary Poisson process with one unit demand at a time. Demands not covered immediately from the inventory are backordered. In a recent paper, the exact evaluation of batch-ordering policies for two-level inventory systems was derived. This evaluation is based on a recursive procedure for determining the exact policy costs in case of one-for-one replenishment policies. In this paper, we show how this result can be applied to find the optimal...