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2016

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Articles 7471 - 7500 of 9606

Full-Text Articles in Engineering

Reaction Parameters And Energy Optimisation For Biodiesel Production Using A Supercritical Process, Nessren Farrag, Mamdouh Gadalla, Mai Fouad Jan 2016

Reaction Parameters And Energy Optimisation For Biodiesel Production Using A Supercritical Process, Nessren Farrag, Mamdouh Gadalla, Mai Fouad

Chemical Engineering

No abstract provided.

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Team Training In Safety And Security Via Simulation : A Practical Dimension Of Maritime Education And Training, Michael Baldauf, Dimitrios Dalaklis, Aditi Kataria Jan 2016

Team Training In Safety And Security Via Simulation : A Practical Dimension Of Maritime Education And Training, Michael Baldauf, Dimitrios Dalaklis, Aditi Kataria

Conference Papers

In the rather extended maritime domain, a term that should be the epicentre of any successful careerbuilding path is tailor-made training via cutting-edge simulators. To cut a long story short, the breadth of operations on the various types of ships has expanded to such a large extent that extensive practical training drills are becoming a compelling need to contribute to competent seafarers. This type of training can guarantee the positive outcome in their decision-making process and help the seafarers often being under continuous pressure, to suitably respond to the various safety and security threats on-board a vessel. The several conventions …

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Effects On Phased Arrays Radiation Pattern Due To Phase Error Distribution In The Phase Shifter Operation, Guiseppe Coviello, Gianfranco Avitabile, Giovanni Piccinni, Giulio D'Amato, Claudio Talarico Jan 2016

Effects On Phased Arrays Radiation Pattern Due To Phase Error Distribution In The Phase Shifter Operation, Guiseppe Coviello, Gianfranco Avitabile, Giovanni Piccinni, Giulio D'Amato, Claudio Talarico

Electrical & Computer Engineering Faculty Scholarship

A comprehensive study on the role of the phase errors distribution on the performances of the phased array systems has been produced. The analysis is brought out using a complete and behavioural model for radiation-pattern characteristics. The study has shown how the phase errors distribution actually affects the performances demonstrating that the rms phase error is a valuable figure of merit of phased array systems but it is not sufficient to completely describe the behaviour of a real system. The paper demonstrates that the antennas array beam shape is depending by the actual error phase distribution and that a good …

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Understanding The Effect Of Extrusion Processing Parameters On Physical, Nutritional And Rheological Properties Of Soy White Flakes Based Aquafeed In A Single Screw Extruder, Sushil Kumar Singh Jan 2016

Understanding The Effect Of Extrusion Processing Parameters On Physical, Nutritional And Rheological Properties Of Soy White Flakes Based Aquafeed In A Single Screw Extruder, Sushil Kumar Singh

Electronic Theses and Dissertations

The rapid expansion of aquaculture has increased the demand for aquafeed. As fishmeal is expensive, alternative plant based protein sources such as soybean has shown to be a good alternative for aquafeed production. The present study was done to investigate the effect of soy white flakes (SWF) as an alternative source of protein in the production of aquaculture feed through extrusion processing. Ingredient blends containing different levels of SWF along with distiller dried grains, corn flour, corn gluten meal, fish meal, vitamin and mineral mix with net protein adjusted to 32% protein were formulated. The ingredient blends were extruded in …

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Mechanical Property Characterization Of Polymeric Composites Reinforced By Continuous Microfibers, Ali Zubayar Jan 2016

Mechanical Property Characterization Of Polymeric Composites Reinforced By Continuous Microfibers, Ali Zubayar

Electronic Theses and Dissertations

Innumerable experimental works have been conducted to study the effect of polymerization on the potential properties of the composites. Experimental techniques are employed to understand the effects of various fibers, their volume fractions and matrix properties in polymer composites. However, these experiments require fabrication of various composites which are time consuming and cost prohibitive. Advances in computational micromechanics allow us to study the various polymer based composites by using finite element simulations. The mechanical properties of continuous fiber composite strands are directional. In traditional continuous fiber laminated composites, all fibers lie in the same plane. This provides very desirable increases …

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Power Management Of Remote Microgrids Considering Battery Lifetime, Santosh Chalise Jan 2016

Power Management Of Remote Microgrids Considering Battery Lifetime, Santosh Chalise

Electronic Theses and Dissertations

Currently, 20% (1.3 billion) of the world’s population still lacks access to electricity and many live in remote areas where connection to the grid is not economical or practical. Remote microgrids could be the solution to the problem because they are designed to provide power for small communities within clearly defined electrical boundaries. Reducing the cost of electricity for remote microgrids can help to increase access to electricity for populations in remote areas and developing countries. The integration of renewable energy and batteries in diesel based microgrids has shown to be effective in reducing fuel consumption. However, the operational cost …

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Oscillating Heat Pipe Performance With Evaporator Section Modifications, Mitchell Hoesing Jan 2016

Oscillating Heat Pipe Performance With Evaporator Section Modifications, Mitchell Hoesing

Electronic Theses and Dissertations

The continuous development of electronic components to become faster and smaller has led to an increasing problem with thermal management. Thermal management ensures that the component operating temperatures are within a safe range, which maintains performance and improves reliability and lifespan. Traditional thermal management devices, such as the extruded-fin heat sink, are incapable of maintaining the safe operating temperature range for current and future high heat flux cooling applications. A device that has the capability to meet this growing need is the oscillating heat pipe. Oscillating heat pipes (OHPs) are passive, two-phase cooling devices that have been shown to transfer …

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The Effects Of Diffuser Exit Velocity And Distance Between Supply And Return Apertures On The Efficiency Of An Air Distribution System In An Office Space, Khaled Abdel Razzaq Saadeddin Jan 2016

The Effects Of Diffuser Exit Velocity And Distance Between Supply And Return Apertures On The Efficiency Of An Air Distribution System In An Office Space, Khaled Abdel Razzaq Saadeddin

Electronic Theses and Dissertations

The distance between supply air diffusers and return air grilles is an important design parameter that has not been properly investigated. Sometimes, design and installation constraints force the engineer or the contractor to place the return duct close to the supply duct which can have a huge impact on the overall efficiency of air distribution in the zone. When the return grille is too close to the supply diffuser, air by-passes the room and flows directly back into the return duct. By-passing of the air in a zone of a building will prevent the heat transfer and the circulation that …

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A Compilation Of Research On Self-Consolidating Concrete For Prestressed Bridge Girders, Eduardo S. Torres Jan 2016

A Compilation Of Research On Self-Consolidating Concrete For Prestressed Bridge Girders, Eduardo S. Torres

Electronic Theses and Dissertations

Self-Consolidating Concrete (SCC) is a relative new concrete technology developed in the 1980s in Japan. Since, SCC has been used for several applications around the world. Initially, SCC was used for on-site applications where it was difficult to place concrete. SCC workability benefits facilitated construction procedures by freely flowing, filling space and passing through dense reinforcement without vibration mechanism. Meanwhile, SCC has also been used in other applications such as the precast industry, where the benefits of the workability SCC delivers can be utilized to improve fabrication of prestressed girders. SCC has been used in the precast industry with a …

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Cascading Failures And Contingency Analysis For Smart Grid Security, Shiva Poudel Jan 2016

Cascading Failures And Contingency Analysis For Smart Grid Security, Shiva Poudel

Electronic Theses and Dissertations

The modern electric power grid has become highly integrated in order to increase the reliability of power transmission from the generating units to end consumers. In addition, today’s power system are facing a rising appeal for the upgrade to a highly intelligent generation of electricity networks commonly known as Smart Grid. However, the growing integration of power system with communication network also brings increasing challenges to the security of modern power grid from both physical and cyber space. Malicious attackers can take advantage of the increased access to the monitoring and control of the system and exploit some of the …

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Characterization Of Mechanical Properties Of Gamma Irradiated Additively Manufactured Articles For In-Space Manufacturing, Behzad Rankouhi Jan 2016

Characterization Of Mechanical Properties Of Gamma Irradiated Additively Manufactured Articles For In-Space Manufacturing, Behzad Rankouhi

Electronic Theses and Dissertations

Recently, additive manufacturing (AM) has opened many doors to engineers across various industries, such as medical, bio-engineering, automotive and recently, aerospace. In an effort to contribute to the development of AM in aerospace industry, a series of experiments were designed to help understand the behavior of 3D printed parts and extend its capabilities and possible uses. The first chapter of this project will focus on understanding the mechanical behavior of additively manufactured articles. In this chapter, a comprehensive effort was undertaken to represent the strength of a 3D printed object as a function of layer thickness by investigating the correlation …

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Frequency Control Of Wind And Pv Based Isolated Microgrid, Lekhnath Kafle Jan 2016

Frequency Control Of Wind And Pv Based Isolated Microgrid, Lekhnath Kafle

Electronic Theses and Dissertations

The wind and solar PV based isolated microgrid can be economical and reliable for the remote area where the grid is not available. The frequency and voltage fluctuation are major problems in such remote microgrid due to intermittent nature of renewable resources like wind and solar PV. The frequency fluctuation should remain within acceptable limits for stable operation of the remote microgrid. This thesis work focuses on frequency control of wind and photovoltaic (PV) based isolated micro-grid using traditional droop control technique. The battery system acts as a master unit which is responsible for setting up the common AC bus …

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Implementation Of Solar Irradiance Forecasting Using Markov Switching Model And Energy Management System, Ayush Shakya Jan 2016

Implementation Of Solar Irradiance Forecasting Using Markov Switching Model And Energy Management System, Ayush Shakya

Electronic Theses and Dissertations

Photovoltaic (PV) systems integration is increasingly being used to reduce fuel consumption in diesel-based remote microgrids. However, uncertainty and low correlation of PV power availability with load reduce the benefits of PV integration. These challenges can be handled by introducing reserve, which however leads to increased operational cost. Solar irradiance forecasting helps to reduce reserve requirement, thereby improving the utilization of PV energy. In this thesis, a new solar irradiance forecasting method for remote microgrids based on the Markov Switching Model (MSM) is presented. This method uses locally available data to predict one-day-ahead solar irradiance for scheduling energy resources in …

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Fully Solution Processed Pedot:Pss And Silver Nanowire Semi-Transparent Electrodes For Thin Film Solar Cells, Bjorn Vaagensmith Jan 2016

Fully Solution Processed Pedot:Pss And Silver Nanowire Semi-Transparent Electrodes For Thin Film Solar Cells, Bjorn Vaagensmith

Electronic Theses and Dissertations

Building integrated photovoltaics (BIPV), such as semitransparent organic solar cells (OSC) for power generating windows, is a promising method for implementing renewable energy under the looming threat of depleting fossil fuels. OSC require a solution processed transparent electrode to be cost effective; but typically employ a nonsolution processed indium tin oxide (ITO) transparent electrode. PEDOT:PSS and silver nanowire transparent electrodes have emerged as a promising alternative to ITO and are solution processed compatible. However, PEDOT:PSS requires a strong acid treatment, which is incompatible with high throughput solution processed fabrication techniques. Silver nanowires suffer from a short lifetime when subject to …

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Product Authentication Using Hash Chains And Printed Qr Codes, Harshith R. Keni Jan 2016

Product Authentication Using Hash Chains And Printed Qr Codes, Harshith R. Keni

Electronic Theses and Dissertations

This thesis explores the usage of simple printed tags for authenticating products. Printed tags are a cheap alternative to RFID and other tag based systems and do not require specialized equipment. Due to the simplistic nature of such printed codes, many security issues like tag impersonation, server impersonation, reader impersonation, replay attacks and denial of service present in RFID based solutions need to be handled differently. An algorithm that utilizes hash chains to secure such simple tags while still keeping cost low is discussed. The security characteristics of this scheme as well as other product authentication schemes that use RFID …

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Application Of New Materials And Innovative Detailing For Reinforced Concrete Structures, Ishtiaque Ahmed Tuhin Jan 2016

Application Of New Materials And Innovative Detailing For Reinforced Concrete Structures, Ishtiaque Ahmed Tuhin

Electronic Theses and Dissertations

Confinement enhances mechanical properties of concrete sections specifically its strain capacity thus results is higher displacement capacity for reinforced concrete members. Even though the behavior of concrete confined with external jackets has been extensively investigated in previous studies, the use of rubber-based material as an external confinement is new, and was investigated for the first time in the present study. Thirty concrete cylinders were tested under uniaxial compression to investigate mechanical properties of rubber confined concrete. It was found that rubber does not increase the strength of confined concrete. However, the strain capacity of rubber confined concrete was more than …

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A Scalable Algorithm For Locating Distribution Centers On Real Road Networks, Saeed Ghanbartehrani, Jose D. Porter Jan 2016

A Scalable Algorithm For Locating Distribution Centers On Real Road Networks, Saeed Ghanbartehrani, Jose D. Porter

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

The median problem is a type of network location problem that aims at finding a node with the total minimum demand weighted distance to a set of demand nodes in a weighted graph. In this research, an algorithm for solving the median problem on real road networks is proposed. The proposed algorithm, referred to as the multi-threaded Dijkstra’s (MTD) algorithm, is then used to optimally locate Wal-Mart distribution centers on the 28-million node road network of the United States with the objective of minimizing the total demand weighted transportation cost. The resulting optimal location configuration of Wal-Mart distribution centers improves …

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Evaluating Transaction Pairing Strategies For Vehicle-Based High-Density Storage Systems, Debjit Roy, Harit Joshie Jan 2016

Evaluating Transaction Pairing Strategies For Vehicle-Based High-Density Storage Systems, Debjit Roy, Harit Joshie

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

Vehicle-based storage and retrieval systems present an attractive choice for distribution center automation because it provides the flexibility in managing demand fluctuations without affecting transaction throughput times. In this research, we contend that while dual-command cycles can reduce the vehicle travel times for processing transactions, it may not be the best policy for reducing transaction throughput times when transactions arrive at random time instants. We develop stochastic models to test the transaction throughput time performance with multiple pairing strategies and present operational insights.

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Continuous Approximation Of Multi Cycle Time For Multi Aisles Automated Storage And Retrieval Systems., Yassine Boudghene Stambouli, Latefa Ghomri Jan 2016

Continuous Approximation Of Multi Cycle Time For Multi Aisles Automated Storage And Retrieval Systems., Yassine Boudghene Stambouli, Latefa Ghomri

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

Knowing that, in an automated storage and retrieval system, the travel time of the storage/retrieval machine is an important parameter which affects the whole system performances, several works were dedicated to its evaluation and its modeling, in single, dual and multi command. These models were proposed for different configurations of AS/RS; such as unit load, multi-aisles and Mobile Racks. These models are based mainly on a discrete approach and the analytical expressions represent the system functioning exactly. In this paper we present a general approach for analytical modeling of multi command cycle time by giving particularly the modeling of the …

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Outsourced Storage And Fulfillment Facility To Enhance The Service Capabilities Of Shopping Mall Tenants, Zachary Montreuil, Mike Ogle Jan 2016

Outsourced Storage And Fulfillment Facility To Enhance The Service Capabilities Of Shopping Mall Tenants, Zachary Montreuil, Mike Ogle

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

This paper proposes development of an Inventory and Fulfillment Center (IFC) that will provide a new range of outsourced, centralized storage and services for shopping mall tenants. The paper describes the competitive issues faced by shopping mall tenants, the requirements and features of a centralized, outsourced storage and fulfillment facility, and development of an agent-based model in AnyLogic® to demonstrate the concept. The range of research and business challenges introduced by this new concept are also presented.

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New Design Guidelines For In-Plant Milk-Run Systems, Thorsten Schmidt, Ingolf Meinhardt, Frank Schulze Jan 2016

New Design Guidelines For In-Plant Milk-Run Systems, Thorsten Schmidt, Ingolf Meinhardt, Frank Schulze

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

Tugger trains became a popular means of supply in material handling intensive production systems. In contrast to forklift trucks they interlink a supermarket with multiple delivery locations along a transport route in a milk-run. But the efficiency gain (higher transport capacity, reduced labor costs) has its price: Compared to forklift trucks, planning and dimensioning of in-plant milk-run systems is more complicated. The paper discusses features and drawbacks of a recent standardization approach of the Association of German Engineers (VDI) and highlights the variety of technical restrictions which have to be considered when a milkrun system is designed. It shows, that …

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The Storage Replenishment Problem In Rectangular Warehouses, Haldun Sural, Claudia Archetti, Melih Celik Jan 2016

The Storage Replenishment Problem In Rectangular Warehouses, Haldun Sural, Claudia Archetti, Melih Celik

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

In warehouses, storage replenishment operations involve the transportation of items to capacitated item slots in forward storage area from reserve storage. These items are later picked from these slots as their demand arises. While order picking constitutes the majority of warehouse operating costs, replenishment operations might be as costly in warehouses where pick lists generally consist of only a few lines (e.g., order fulfillment warehouses). In this study, we consider the storage replenishment problem in a parallel-aisle warehouse, where replenishment and order picking operations are carried out in successive waves with time limits. The aim is to determine the item …

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Performance Comparison Of Automated Warehouses Using Simulation, Nand Kishore Agrawal, Sunderesh S. Heragu, Chinnatat Methapatra Jan 2016

Performance Comparison Of Automated Warehouses Using Simulation, Nand Kishore Agrawal, Sunderesh S. Heragu, Chinnatat Methapatra

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

The purpose of this study is to compare the performance of two types of warehouses, both of which use autonomous vehicles (AVs). One warehouse uses movable racks (MR) for storing mini-loads, whereas the other uses fixed racks (FR). In general, warehouse automation not only increases the speed of the fulfillment process but also makes the picking process more accurate. We simulate three scenarios for the MR and FR systems using Simio. Four performance measures are considered for the comparison – the average order processing time (WR), the average utilization of AVs (U), the average order processing queue length (Nq) and …

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Job Sequencing In A Miniload System, Lennart Baardman, Kees Jan Roodbergen Jan 2016

Job Sequencing In A Miniload System, Lennart Baardman, Kees Jan Roodbergen

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

More and more warehouses shift towards the use of automated systems. One such system is a miniload system. In this system, a crane retrieves bins from their storage locations and brings the bins to the picking station, where a worker takes the requested products from the retrieved bins. After a product has been picked, the bin is put back by the crane in its original location. A buffer is present at the picking station to absorb fluctuations in speed between the picker and the crane. The problem of scheduling jobs in this system has received little attention in the literature. …

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Dual-Tray Vertical Lift Modules For Fast Order Picking, Daria Battini, Martina Calzavara, Alessandro Persona, Fabio Sgarbossa Jan 2016

Dual-Tray Vertical Lift Modules For Fast Order Picking, Daria Battini, Martina Calzavara, Alessandro Persona, Fabio Sgarbossa

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

In the last years, new solutions for order picking systems have been developed both from industry and academics, especially for small items. They include innovative flexible automatic parts-to-picker systems and optimized picker-to-parts ones. One of these solutions consists in the use of Vertical Lift Modules (VLMs), a storage column in which small items are stored in extractable trays. In this paper, we study a new system composed by dual-tray VLMs where the operators perform picking and sorting activities. We propose several actions in order to improve the productivity of the entire system: 1) class based storage assignment of items inside …

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Throughput Rate Of A Two-Worker Stochastic Bucket Brigade, Yossi Bukchin, Eran Hanany, Eugene Khmelnitsky Jan 2016

Throughput Rate Of A Two-Worker Stochastic Bucket Brigade, Yossi Bukchin, Eran Hanany, Eugene Khmelnitsky

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

Work-sharing in production systems is a modern approach that improves throughput rate. Work is shifted between cross-trained workers in order to better balance the material now in the system. When a serial system is concerned, a common work-sharing approach is the Bucket-Brigade (BB), by which downstream workers sequentially take over items from adjacent upstream work- ers. When the workers are located from slowest-to-fastest and their speeds are deterministic, it is known that the line does not suffer from blockage or starvation, and achieves the maximal theoretical throughput rate (TR). Very little is known in the literature on stochastic self-balancing systems …

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A Performance Measurement Framework And Solution Approach For The Integrated Facility Layout Problem With Uncertain Demand, Melih Celik, Begun Efeoglu, Haldun Sural Jan 2016

A Performance Measurement Framework And Solution Approach For The Integrated Facility Layout Problem With Uncertain Demand, Melih Celik, Begun Efeoglu, Haldun Sural

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

The integrated facility layout problem (IFLP) focuses on the simultaneous determination of the relative locations of multiple copies of capacitated equip- ment or machinery in a facility, as well as the material ow between these units. In this paper, we consider the IFLP in the existence of uncertain demand for the products of the facility. Motivated by the framework for next generation facility layouts by Benjaafar et al. (2002), we extend the approaches in the lit- erature for distributed facility layouts to the case of dynamic demand and the possibility of relayouts, and propose a heuristic solution approach to minimize …

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Transport Items And Physical Internet Handling Boxes: A Comparison Framework Across Supply Chains, Eric Ballot, Benoit Montreuil Jan 2016

Transport Items And Physical Internet Handling Boxes: A Comparison Framework Across Supply Chains, Eric Ballot, Benoit Montreuil

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

Pallets, cardboard boxes, and plastic crates are widely used tools to operate supply chains. As such they have many impacts on handling effort, shipment protection, transport mean utilization as well as repositioning and recycling efforts and they represent billions of assets spread all over the world. The historical and local origins of the designs and the sharing among many stakeholders do not ensure at all any kind of global optimization. The purpose of this paper is to define and explain a research effort to better measure and evaluate the efficiencies and inefficiencies for supply chain stakeholders for themselves and globally. …

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Energy And Cycle Time Efficient Warehouse Design For Autonomous Vehicle-Based Storage And Retrieval System, Banu Yetkin Ekren, Tone Lerher Jan 2016

Energy And Cycle Time Efficient Warehouse Design For Autonomous Vehicle-Based Storage And Retrieval System, Banu Yetkin Ekren, Tone Lerher

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

This study explores the best warehouse design for an autonomous vehicle based storage and retrieval system (AVS/RS) minimizing average energy consumption per transaction and average cycle time per transaction, simultaneously. In the design concept, we consider, rack design in terms of number of bays, number of tiers, number of aisles; number of resources, namely number of autonomous vehicles and lifts and; velocity profiles of lifts and autonomous vehicles in the AVS/RS. We completed 1,296 number of experiments in simulation to obtain Pareto solutions representing the “average energy consumption per transaction” and “average cycle time per transaction” trade-offs based on designs …

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Determination Of Cycle Times For Double Deep Storage Systems Using A Dual Capacity Handling Device, Katharina Dorr Jan 2016

Determination Of Cycle Times For Double Deep Storage Systems Using A Dual Capacity Handling Device, Katharina Dorr

14th IMHRC Proceedings (Karlsruhe, Germany – 2016)

Double deep storage is an efficient method to improve space utilization in warehouses. Contrary to intuition, it also can be efficient when considering retrieval times, since the aisles of a warehouse with double deep storage may be shorter than comparable warehouses with single deep storage. AS/RS-machines equipped with two load-handling units might further improve the situation, since two storage units (for instance pallets or cases) can be stored and retrieved, effectively allowing quadruple command cycles, bringing in total two storage units into the aisle and retrieving two storage units at the same time. In this paper, we present a method …

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