Templated self-assembly of nanoporous alumina : pore formation and ordering mechanisms, methodologies, and applications

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2005.MIT Institute Archives copy: p. 301-324 bound in reverse order.Includes bibliographical references (p. 309-324).Porous anodic aluminum oxide (AAO), also known as porous alumina, is a self-ordered nanostructured material well-suited for use in electronic, magnetic, optical and biological applications due to its small pore size (4-200nm) and spacing (10-500nm). Under slightly acidic conditions, both oxidation and dissolution of aluminum leads to the formation of pores. AAO pores form a self-assembled honey-comb structure with short range order over certain ranges of anodic potential and pH. In this work, three key results related to porous AAO science and technology are presented. First, a new theory based on strain-induced instability has been developed from the analysis of results obtained from kinetic studies and stress measurements to explain the formation of AAO pores. Experiments show that excess vacancies of aluminum, created by the dissolution process, generate a large tensile stress and an associated strain energy, which destabilizes the initially flat A1/AAO interface and leads to pore formation. Other factors affecting stability of the Al/AAO interface and the self-assembly process are also presented.(cont.) Second, templated self-assembly (TSA) of AAO pores, ordered over wafer-scale areas and with controlled spacing and symmetry, have been achieved by pre-patterning the substrate using interference lithography. TSA of AAO pores led to control of pore spacing and order symmetry in ranges not achievable without templating. Independent control of pore spacing and diameter were successfully demonstrated, allowing formation of novel 3-D nanostructures such as nanofunnels, fabricated using periodic variations in the anions and/or electrolyte pH. Using the TSA approach, AAO with ordered pores 50:1 were fabricated on Si substrates. A 1-D array of ordered pores, either in or out of plane with the substrate, was fabricated by confining the growth of AAO pores using silicon oxide masks patterned by lithography techniques. Finally, AAO templates were used to fabricate ordered nanostructures including carbon nanotubes, magnetic nanotubes and antidots, and metallic nanowires and nanoparticles, all of which display properties very different from their bulk counterparts.(cont.) These results, and other proposed methodologies, provide new techniques for controlled in-plane and out-of-plane growth and organization of nanotubes and nanowires on Si substrates.by Ramkumar Krishnan.Ph.D

A Roadmap For Customer Relationship Management

Customer Relationship Management (CRM) has become yet another bandwagon in the crowded caravans towards strategic information systems nirvana. In this paper, we contend that beyond serving as a buzzword and a passing fad to acquire an Information Technology (IT) solution from clamoring vendors, managements enthusiasm for CRM can effectively be cultivated to develop the organizations strategic plan for making the customer the focal point of all activities. To that end, we examine CRM technologies by considering what they offer for managing each stage of the Customer Resource Life Cycle (CRLC)

Simulation Study for Multi-Echelon Multi-Depot Supply Chain System Using Live Data

The manufacturing industry is eager to implement the advancements of the fourth industrial revolution (Industry 4.0) due to the magnitude of the benefits it can provide. Hence, Industry 4.0 opens a wide avenue for researchers to explore possibilities in the field of the supply chain. This project focuses on building a decision framework for a supply chain system with disruptions. The impact of strategic decisions under the condition of unprecedented events for a vehicle routing problem (VRP) using simulation models is studied here. Those results help the supply chain managers in making sound decisions regarding different scenarios of disruption in VRP. To achieve this, multiple cases under different scenarios of facility disruption are considered. For all cases, the dependent parameter, namely, retailer service level and lost revenue, form the basis of the decision framework. The concept of live data is implemented by making retailer demand, current inventory at the depot, the position of the vehicle in the network and the current number of units in transit as the input data

Optimal Supply Chain Network with Multi-Echelon

The study of the effect of redistribution strategy and aggregation, on a multi-echelon supply chain network by managing demand volatility is discussed in this research. For this an operational supply chain design is considered. Multi-echelon network consisting of manufacturing plants, distribution centers, warehouses, and retailers is used to develop the case study. Aggregation strategy was analyzed in the context of single product and multi-product for a multi-period production problem under demand uncertainty. Product sourcing between echelons and distribution strategies are considered for the study. Objective was to use the redistribution strategy to optimize the objective functions for the network. The objective functions include minimization of total cost, minimization of overage and stock-out conditions, and maximization of the customer service level. The total cost function includes product flow, transportation cost and distance cost. The mathematical formulation is carried out in Mixed Integer Linear Programming (MILP) with the help of Generic Algebraic Modeling System (GAMS). Problem formulation considers three type of demand based on volatility and uncertainty cases as high, medium, and low. The research is divided into three main phases to discuss an optimal multi-echelon supply chain network for single product using aggregation strategy

Optimization of multipoint incremental sheet metal forming of SS430 sheets using GRA

326-333Incremental sheet metal forming (ISF) is one of the best flexible manufacturing processes used to convert a sheet metal into required final shape using tool movement. In incremental sheet metal forming process, a single pointed forming tool is allowed to move over the sheet metal as per the pre-programmed numerical control of a computer. The advantage of making any complex part without die confirms its importance in the emerging automated industries. But this process has some limitations such as less formability and high surface roughness compared to the conventional forming process. Longer processing time is another drawback of the incremental sheet forming. This paper proposes a newly designed multi-point incremental forming (MPIF) tool to avoid the drawbacks faced by industry in increasing the formability and wall angle of the sheet metal with reduced time. The sheet metal stainless steel (SS) grade 430 has been used for forming process and the outputs obtained from MPIF and single point incremental forming (SPIF) have been compared with respect to wall angle, formability, surface roughness, spring back and forming time. Grey relational analysis (GRA) has been used to find the optimal value for the various responses obtained. The analysis of variance (ANOVA) calculation method has also been used to find the factors that influence the output responses. The responses obtained by the experiment have proved that the multipoint tool results better output

EMR Adoption: A User Perception Study

Despite promise of significant benefits, inadequate user acceptance has frequently limited the impact of EMR implementations. Using an action research approach, our team is participating in an EMR implementation at Aravind Eye Care System (AECS), one of the largest eye hospitals in the world, to observe its current practices, measure user perceptions of EMR, plan interventions, and assess their impact. Our proximate research objective is to develop interventions based on sound conceptual foundations and empirical validation rather than in an ad hoc manner, to facilitate EMR acceptance by AECS hospital staff. The ensuing goal is to learn from the post intervention findings to develop guidelines for EMR implementations, particularly in a developing country context. In this paper we report on the first phase of this study, and these initial results show how even simple analysis of perception patterns can help to customize and shape intervention plans

Fishery and Exploitation of Malabar Grouper, Epinephelus malabaricus (Bloch & Schneider 1801) from Andaman Islands

The fishery and population dynamics of groupers from Andaman Islands were studied from Jan 2010 to Dec 2011 with a special emphasis on Malabar grouper, Epinephelus malabaricus (Bloch & Schneider 1801). The average annual catch of Malabar grouper was 1,296 tonnes contributing to 21.6% of annual grouper landings. Length-weight relationship of Malabar grouper showed that growth was allometric (b=2.96) and relative condition factor (Kn) was 1 and the growth parameters viz., L∞, K and t0 were 124.60 cm, 0.80 and -0.05 respectively. The recruitment pattern was unimodal with one major peak during April to July throughout the study period. The natural mortality (M), fishing mortality (F) and total mortality (Z) were 1.05, 1.48 and 2.53 respectively and exploitation rate (E) was 0.58. The M/K ratio (1.31) was found to be well within the normal range of 1to 2.5. Catch per unit effort varied from 4 to16.5 kg.h-1. The maximum sustainable yield (MSY) was 1,107 tonnes which was lower than the average annual catch (1,296 tonnes), indicating over exploitation. The current study calls for further research in identifying the grouper fishing and spawning aggregation grounds and introduce measures for reducing fishing efforts with input and output controls to sustain the Malabar grouper fishery in Andaman waters

A Patient-centric, Attribute-based, Source-verifiable Framework for Health Record Sharing

The storage of health records in electronic format, and the wide-spread sharing of these records among different health care providers, have enormous potential benefits to the U.S. healthcare system. These benefits include both improving the quality of health care delivered to patients and reducing the costs of delivering that care. However, maintaining the security of electronic health record systems and the privacy of the information they contain is paramount to ensure that patients have confidence in the use of such systems. In this paper, we propose a framework for electronic health record sharing that is patient centric, i.e. it provides patients with substantial control over how their information is shared and with whom; provides for verifiability of original sources of health information and the integrity of the data; and permits fine-grained decisions about when data can be shared based on the use of attribute-based techniques for authorization and access control. We present the architecture of the framework, describe a prototype system we have built based on it, and demonstrate its use within a scenario involving emergency responders' access to health record information