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Full-Text Articles in Mechanical Engineering

Silicon Oxide Micromodule Capacitors, W. B. Nowak, J. J. O'Connor Dec 2010

Silicon Oxide Micromodule Capacitors, W. B. Nowak, J. J. O'Connor

Welville B. Nowak

Silicon oxide capacitors have been developed on micromodule wafers (0.310-in. sq. with three termination notches per side). Each microelement contains 1, 2, 3, or 4 capacitors with values of 1120 and 560, 180, 100 and 68 pf per capacitor, respectively. The 1120 pf capacitor is double layered. In addition to the general requirements of microelements and micromodules, some of the more important specifications these capacitors must meet are: dissipation factor (DF) not exceeding 0.015, insulation resistance (IR) at 50 volts exceeding 10,000 megohms (25°C) and 750 megohms (125°c), 50 WVDC and 150 volts dielectric withstanding voltage (DWV), Δ C not …


Structural And Magnetic Characterization Of Amorphous Gd₂Fe₁₄B Thin Films, S. E. Bushnell, P. C. Dorsey, W. B. Nowak, C. Vittoria Dec 2010

Structural And Magnetic Characterization Of Amorphous Gd₂Fe₁₄B Thin Films, S. E. Bushnell, P. C. Dorsey, W. B. Nowak, C. Vittoria

Welville B. Nowak

Thin amorphous films of nominal composition Gd₂Fe₁₄B were fabricated on Si (100) substrates using ion‐beam sputtering for the purpose of establishing their structural and magnetic properties at room temperature. X‐ray‐diffraction scans performed on as‐deposited and annealed films revealed an amorphous structure. The as‐deposited saturation magnetization was found to be 8101 G at room temperature suggesting ferrimagnetic ordering with anti‐parallel coupling similar to other heavy rare earth‐transition metal systems. Results from in‐plane and perpendicular ferromagnetic resonance experiments conducted at 9.108 GHz showed the films to be inhomogeneous. This was evident from the presence of two in‐plane resonance lines and spin‐wave spectra …


The Measurement Of Magnetostriction Constants Of Thin Films Using Planar Microwave Devices And Ferromagnetic Resonance, S. E. Bushnell, W. B. Nowak, S. A. Oliver, C. Vittoria Dec 2010

The Measurement Of Magnetostriction Constants Of Thin Films Using Planar Microwave Devices And Ferromagnetic Resonance, S. E. Bushnell, W. B. Nowak, S. A. Oliver, C. Vittoria

Welville B. Nowak

In this paper we introduce a new technique for measuring the saturation magnetostriction constant (λs) for isotropic polycrystalline thin films. The technique makes use of nonresonant planar microwave structures together with a novel stressing mechanism to induce a shift in the resonant field of a magnetic thin film as measured by a ferromagnetic resonance (FMR) experiment. Measurement of the shift induced by a uniaxial stress allows for determination of λs via a magnetic resonance analysis. Either a slotline device or coplanar waveguide (CPW) was used as the source of the microwave excitation field depending upon the orientation of the dc …


Magnetic And Structural Investigation Of Heat Treated Ion Beam Sputtered Amorphous Co₇₄Fe₆B₁₅Si₅ Films, V. G. Harris, S. A. Oliver, W. B. Nowak, C. Vittoria, R. J. Culbertson, W. T. Elam, K. H. Kim Dec 2010

Magnetic And Structural Investigation Of Heat Treated Ion Beam Sputtered Amorphous Co₇₄Fe₆B₁₅Si₅ Films, V. G. Harris, S. A. Oliver, W. B. Nowak, C. Vittoria, R. J. Culbertson, W. T. Elam, K. H. Kim

Welville B. Nowak

As-deposited and annealed specimens of ion beam sputtered amorphous Co₇₄Fe₆B₁₅Si₅ thin films were examined to explore the correlation between changes in magnetic properties and atomic structure. Specimens were characterized magnetically, by traditional ac and dc techniques and structurally, via conversion-electron extended x-ray absorption fine structure analysis. Results show significant ordering of the higher order atomic shells around the transition metal ions well below the crystallization temperature. This ordering evolves into a body- centered-cubic configuration around both the Co and Fe ions. Increases in nearest neighbor peak positions in the EXAFS Fourier transforms were observed to correlate with increasing annealing temperatures. …


Magnetic And Microwave Properties Of Ion-Beam-Sputtered Amorphous Feₓco₈₀₋ₓb₁₅Si₅ Films, V. G. Harris, S. A. Oliver, W. B. Nowak, C. Vittoria Dec 2010

Magnetic And Microwave Properties Of Ion-Beam-Sputtered Amorphous Feₓco₈₀₋ₓb₁₅Si₅ Films, V. G. Harris, S. A. Oliver, W. B. Nowak, C. Vittoria

Welville B. Nowak

Magnetically soft amorphous films of FeₓCo₈₀₋ₓB₁₅Si₅ (x = 0, 6, 23, 40, 70, 80) were ion beam sputter deposited onto fused quartz for static and microwave magnetic characterization. Films ranged in thickness from 220 to 260 nm and were deposited at rates of 0.1-0.2 nm/s. Saturation magnetization, coercivity, and loop squareness values were extracted from hysteresis loops generated by a vibrating sample magnetometer. Ferromagnetic resonance measurements were taken using a 9.5-GHz cavity with the applied magnetic field both parallel and perpendicular to the plane of the film, yielding values for the g factor, anisotropy field, effective magnetization, and linewidth. Well …


A Bi-Directional Supply Chain Optimization Model For Reverse Logistics, Surendra M. Gupta, Pitipong Veerakamolmal Oct 2010

A Bi-Directional Supply Chain Optimization Model For Reverse Logistics, Surendra M. Gupta, Pitipong Veerakamolmal

Surendra M. Gupta

This paper focuses an supply chain optimization system for reverse logistics. The solution approach employs an adaptation of the Materials Requirements Planning (MRP) technique, termed as components requirements planning, to determine the number of components needed to remanufacture products in each time period throughout the planning horizon.


Greedy Algorithm For Disassembly Line Scheduling, Seamus M. Mcgovern, Surendra M. Gupta Oct 2010

Greedy Algorithm For Disassembly Line Scheduling, Seamus M. Mcgovern, Surendra M. Gupta

Surendra M. Gupta

Remanufacturing, recycling, and disposal recovery operations require the performance of disassembly activities. The disassembly line is the best choice for automated disassembly of returned products, however, finding the optimal balance is computationally intensive with exhaustive search quickly becoming prohibitively large. In this paper, a greedy algorithm is presented for obtaining optimal or near-optimal solutions to the disassembly line balancing problem. The greedy algorithm is a first-fit decreasing algorithm further enhanced to preserve precedence relationships. The algorithm seeks to minimize the number of workstations while accounting for hazardous and high demand components. A hill-climbing heuristic is then developed to balance the …


A Multi-Phase Fuzzy Logic Approach To Strategic Planning Of A Reverse Supply Chain Network, Kishore K. Pochampally, Surendra M. Gupta Oct 2010

A Multi-Phase Fuzzy Logic Approach To Strategic Planning Of A Reverse Supply Chain Network, Kishore K. Pochampally, Surendra M. Gupta

Surendra M. Gupta

Strategic planning (also called designing) is a challenging aspect of a reverse supply chain network. To effectively satisfy drivers such as profitability, environmental regulations, and asset recovery, only the most economical used products must be reprocessed in only the recovery facilities that have the potential to efficiently reprocess them. Due to uncertainties in supply, quality, and reprocessing times of used products, the cost-benefit function in the literature that selects the most economical product to reprocess from a set of used products is not appropriate for direct adoption. Moreover, due to the same uncertainties, any traditional forward supply chain approach to …


Pricing Of End-Of-Life Items With Obsolescence, Srikanth Vadde, Sagar V. Kamarthi, Surendra M. Gupta Oct 2010

Pricing Of End-Of-Life Items With Obsolescence, Srikanth Vadde, Sagar V. Kamarthi, Surendra M. Gupta

Surendra M. Gupta

Variability in the inflow of end-of-life (EOL) products and fluctuating inventory levels often make the processing of EOL products an economically risky operation for product recovery facilities (PRFs). Choosing an appropriate pricing policy can enhance the performance of PRFs by methodically clearing their inventory and increasing profits. This work presents two pricing models to counter the prospect of product obsolescence that can happen either gradually or suddenly. Product obsolescence can cause demand drop and inventory pile up, both of which could dent the revenues of PRFs. In the first model, gradual obsolescence and environmental regulations that limit the disposal quantity …


Product Recovery Using A Disassembly Line : Challenges And Solution, Surendra M. Gupta, Askiner Gungor Oct 2010

Product Recovery Using A Disassembly Line : Challenges And Solution, Surendra M. Gupta, Askiner Gungor

Surendra M. Gupta

Disassembly plays an important role in product recovery by allowing selective separation of desired parts and materials. The disassembly line is the best choice for automated disassembly of returned products, a feature that will be essential in the future. It is, therefore, important that the disassembly line be designed and balanced so that it works as efficiently as possible. In this paper, the authors address the disassembly line balancing problem and the challenges that come with it.


Disassembly Process Planning Using Petri Nets, Kendra E. Moore, Askiner Gungor, Surendra M. Gupta Oct 2010

Disassembly Process Planning Using Petri Nets, Kendra E. Moore, Askiner Gungor, Surendra M. Gupta

Surendra M. Gupta

We generate a disassembly PN (DPN) from a disassembly precedence matrix. The resulting DPN can be analyzed using the reachability tree method to generate all feasible disassembly process plans (DPPs), and cost functions can be used to determine the optimal DPP. Since generating the reachability tree is NP-complete, we develop a heuristic algorithm to limit the size of the reachability tree. The algorithm employs multihypothesis search to dynamically explore the v likeliest lowest cost branches of the tree, in order to identify near-optimal DPPs. The cost function incorporates tool changes, changes in direction movement, and individual part characteristics (e.g., hazardous). …


Determining Optimum And Suboptimum Disassembly Sequences With An Application To A Cell Phone, A.J.D. (Fred) Lambert, Surendra M. Gupta Oct 2010

Determining Optimum And Suboptimum Disassembly Sequences With An Application To A Cell Phone, A.J.D. (Fred) Lambert, Surendra M. Gupta

Surendra M. Gupta

We study the disassembly process of a moderately complex consumer product (cell phone) consisting of 25 components. The investigation involves a heuristically solved disassembly line balancing problem and the determination of an appropriate disassembly sequence influenced by sequence-dependent costs, which is based on a novel combination of exact and heuristic algorithms. The issue of generating various suboptimum solutions to cope with multiple optimization criteria is also discussed.


Planning An Efficient Closed-Loop Supply Chain Network : A Unified Single Phase Approach, Satish Nukala, Surendra M. Gupta Oct 2010

Planning An Efficient Closed-Loop Supply Chain Network : A Unified Single Phase Approach, Satish Nukala, Surendra M. Gupta

Surendra M. Gupta

No abstract provided.


Efficient Design And Effective Marketing Of A Reverse Supply Chain : A Fuzzy Logic Approach, Kishore K. Pochampally, Surendra M. Gupta Oct 2010

Efficient Design And Effective Marketing Of A Reverse Supply Chain : A Fuzzy Logic Approach, Kishore K. Pochampally, Surendra M. Gupta

Surendra M. Gupta

A two-phase mathematical programming approach to efficiently design a reverse supply chain is proposed, as follows: in phase I, a fuzzy cost-benefit function is formulated to perform a multi-criteria economic analysis for selecting the most economical product to re-process, from a set of candidate used products; in phase II, an integer goal programming model that not only identifies potential recovery facilities but also leads to transportation of the right mix and quantities of products (used as well as re-processed) across the supply chain, is formulated. Since the success of a reverse supply chain depends on its marketing strategy as well …


Disassembly Petri Net Generation In The Presence Of Xor Precedence Relationships, K. E. Moore, Askiner Gungor, Surendra M. Gupta Oct 2010

Disassembly Petri Net Generation In The Presence Of Xor Precedence Relationships, K. E. Moore, Askiner Gungor, Surendra M. Gupta

Surendra M. Gupta

A disassembly process plan (DPP) is a sequence of disassembly tasks which begins with a product to be disassembled and terminates in a state where all the parts of interest are disconnected. Disassembly process planning is critical for minimizing the resources invested in disassembly and maximizing the level of automation of the disassembly process and the quality of the parts (or materials) recovered. In this paper, we propose an algorithm which automatically generates a disassembly PN (DPN) from a geometrically-based disassembly precedence matrix (DPM). This algorithm can be used to generate DPPs for products which contain simple AND, OR, complex …


Disassembly-To-Order System Using Linear Physical Programming, Elif Kongar, Surendra M. Gupta Oct 2010

Disassembly-To-Order System Using Linear Physical Programming, Elif Kongar, Surendra M. Gupta

Surendra M. Gupta

One of the most responsible ways of processing end-of-life (EOL) products is to minimize their disposal to landfills by reusing, remanufacturing and/or recycling them. Often, this necessitates a certain level of disassembly. It is therefore necessary to plan disassembly processing efficiently so as to minimize costs and the amount of disposal as well as to maximize reuse, remanufacturing and recycling. In this paper, we present a disassembly-to-order system to determine the number of EOL products to process to fulfill a certain demand for products, parts and/or materials under a variety of objectives and constraints using a newly developed decision tool, …


A Stochastic Inventory Management Approach In The Disassembly Line Portion Of Reverse Logistics, Badr O. Johar, Surendra M. Gupta Sep 2010

A Stochastic Inventory Management Approach In The Disassembly Line Portion Of Reverse Logistics, Badr O. Johar, Surendra M. Gupta

Surendra M. Gupta

Reverse logistics is a critical topic that has captured the attention of government, private entities and researchers in recent years. This increase in the concern was driven by current set of government regulations, increase of public awareness, and the attractive economic opportunities. As a result, many corporations have started to comprehend the importance of the recovery process and are taking serious steps in restructuring their supply chain processes to meet the new regulations such as limitations on waste disposal and recycling requirements [1]. Because of the unique problems associated with reverse supply chain and the complex nature of the reverse …


Analysis Of A Kanban Controlled Disassembly Line With Sensor Embedded Products, Mehmet Ali Ilgin, Surendra M. Gupta Sep 2010

Analysis Of A Kanban Controlled Disassembly Line With Sensor Embedded Products, Mehmet Ali Ilgin, Surendra M. Gupta

Surendra M. Gupta

The use of sensors in the detection of non-functional or missing components in a product before disassembling it is a promising approach to deal with the high level uncertainty associated with disassembly yield. This study presents a quantitative assessment of the impact of the sensor embedded products on the various performance measures of a kanban-controlled disassembly line. First, two separate design of experiments studies based on Orthogonal Arrays are carried out for the cases with and without sensor embedded products. Then, the results of paired-t tests comparing two cases based on different performance measures are presented.


Analysis Of Remanufacturing Policy With Consideration For Returned Products Quality, Kenichi Nakashima, Surendra M. Gupta Sep 2010

Analysis Of Remanufacturing Policy With Consideration For Returned Products Quality, Kenichi Nakashima, Surendra M. Gupta

Surendra M. Gupta

This paper deals with the product acquisition control problem and considers returned product quality with two types of classes. The system includes the flow of the product returns from customers to the factory as well as the forward flow of the sales. We formulate the acquisition problem together with product quality and stochastic demand using the Markov decision process. A numerical example is given to show the implementation of the methodology.


The Effect Of Disassembly Process On Spare Parts Inventory Management In Post Product Life Cycle, Mehmet Ali Ilgin, Surendra M. Gupta Sep 2010

The Effect Of Disassembly Process On Spare Parts Inventory Management In Post Product Life Cycle, Mehmet Ali Ilgin, Surendra M. Gupta

Surendra M. Gupta

Timely and cost-effective acquisition of spare parts at post product life cycle (PPLC) is a challenging task due to limited supply of new spare parts. The most commonly used solution to this problem is the placement of a final order in the beginning of PPLC. Another alternative is the use of disassembled parts from End of Life (EOL) products. In this study, we consider both alternatives at the same time. First, a detailed discrete event simulation (DES) model of a disassembly line is developed. Then, a Genetic Algorithm (GA) is integrated with the DES model for the optimization of Final …


Disassembly Of Sensor Embedded Products With Component Discriminating Demand, Mehmet Ali Ilgin, Surendra M. Gupta Sep 2010

Disassembly Of Sensor Embedded Products With Component Discriminating Demand, Mehmet Ali Ilgin, Surendra M. Gupta

Surendra M. Gupta

There is a high level uncertainty associated with disassembly yield due to existence of unfunctional and/or unneeded components in end of life products. Sensors embedded in critical components of a product can deal with this uncertainty by providing information on the type and condition of the components prior to disassembly. This study presents a quantitative assessment of the impact of sensor embedded products (SEPs) on the various performance measures of a kanban-controlled washing machine disassembly line. First, separate design of experiments studies based on orthogonal arrays are performed for the cases with and without SEPs. Then, the results of paired-t …


Preemptive Goal Programming For Solving The Multi-Criteria Disassembly-To-Order Problem Under Stochastic Yields, Limited Supply, And Quantity Discount, Amre Z. Massoud, Surendra M. Gupta Sep 2010

Preemptive Goal Programming For Solving The Multi-Criteria Disassembly-To-Order Problem Under Stochastic Yields, Limited Supply, And Quantity Discount, Amre Z. Massoud, Surendra M. Gupta

Surendra M. Gupta

This paper considers the disassembly-to-order (DTO) problem where end-of-life (EOL) products are purchased for disassembly in order to satisfy the demand for specified numbers of components. Previous work in the literature solved the DTO problem with multiple uncertainties under a single objective while others solved the multi-criteria model with a single uncertainty. This paper develop a multi-criteria DTO model that would takes into consideration multiple system uncertainties and variability. The multi-criteria DTO model was solved using preemptive goal programming (PGP). The main objective was to determine optimal number of take-back EOL products in every period from each supplier in order …


Use Of Crystal Ball® To Predict Profitability Of A Reverse Supply Chain, Kishore K. Pochampally, Surendra M. Gupta, Tej S. Dhakar Sep 2010

Use Of Crystal Ball® To Predict Profitability Of A Reverse Supply Chain, Kishore K. Pochampally, Surendra M. Gupta, Tej S. Dhakar

Surendra M. Gupta

Traditionally, firms have been spending significant time and money in improving their forward supply chains while ignoring their potential reverse supply chains. However, in today’s competitive business environment, it is important that firms study the profitability and benefits of implementing a reverse supply chain while considering the uncertainties associated with the supply and composition of used products, disassembly time, recycling/remanufacturing time, and demand for recycled/remanufactured goods. In this paper, we demonstrate how a simulation software package, Crystal Ball®, can be used to help a firm predict whether investment in a reverse supply chain is profitable with respect to a given …


A Genetic Algorithm Approach To End-Of-Life Disassembly Sequencing For Robotic Disassembly, Ahmed Elsayed, Elif Kongar, Surendra M. Gupta Sep 2010

A Genetic Algorithm Approach To End-Of-Life Disassembly Sequencing For Robotic Disassembly, Ahmed Elsayed, Elif Kongar, Surendra M. Gupta

Surendra M. Gupta

End-of-life (EOL) processing options include reuse, remanufacturing, recycling and proper disposal. In almost all cases, a certain level of disassembly may be required due to possible changes in the original product structure. Thus, finding an optimal or near optimal disassembly sequence is crucial to increasing the efficiency of the process. Disassembly operations are labor intensive, can be costly, have unique characteristics and cannot be considered as reverse of assembly operations. Since the complexity of determining the best disassembly sequence increases as the number of parts of the product grow, an efficient methodology is reuired for disassembly sequencing. In this paper, …


Improving Clinical Access And Continuity Through Physician Panel Redesign, Hari Balasubramanian, Ritesh Banerjee, Brian Denton, James Naessens, James Stahl Jun 2010

Improving Clinical Access And Continuity Through Physician Panel Redesign, Hari Balasubramanian, Ritesh Banerjee, Brian Denton, James Naessens, James Stahl

Hari Balasubramanian

BACKGROUND: Population growth, an aging population and the increasing prevalence of chronic disease are projected to increase demand for primary care services in the United States. OBJECTIVE: Using systems engineering methods, to re-design physician patient panels targeting optimal access and continuity of care. DESIGN: We use computer simulation methods to design physician panels and model a practice’s appointment system and capacity to provide clinical service. Baseline data were derived from a primary care group practice of 39 physicians with over 20,000 patients at the Mayo Clinic in Rochester, MN, for the years 2004–2006. Panel design specifically took into account panel …


Antimicrobial And Antioxidant Activities Of Essential Oil And Methanol Extract Of Jasminum Sambac From Djibouti, Fatou Abdoul-Latif, Prosper Edou, François Eba, Nabil Mohamed, Adwa Ali, Samatar Djama, Louis-Clément Obame, Mamoudou Hama Dicko Mar 2010

Antimicrobial And Antioxidant Activities Of Essential Oil And Methanol Extract Of Jasminum Sambac From Djibouti, Fatou Abdoul-Latif, Prosper Edou, François Eba, Nabil Mohamed, Adwa Ali, Samatar Djama, Louis-Clément Obame, Mamoudou Hama Dicko

Pr. Mamoudou H. DICKO, PhD

The essential oil of jasminum sambac from Djibouti was subjected to screening for their possible antioxidant activity by two complementary test systems, namely DPPH free radical scavenging and beta-carotene-linoleic acid assays. Butylated hydroxytoluene (BHT) was used as positive control in both test systems. In the DPPH test system, the IC50 value of essential oil and methanol extract were respectively 7.43 and 2.30 μg/ml. In the beta-carotene-linoleic acid system, oxidation was effectively inhibited by Jasminum sambac, the RAA value of essential oil and methanol extract were respectively 96.6 and 93.9%. When compared to BHT, the essential oil and methanol extract had …