A Case Study for Financial Feasibility of Automated Costing Support in A Small Machine Shop

A knowledge-based cost estimating expert system is chosen by a Mexican machine shop. Differences between the traditional experience-based system employed and the automated system are studied. Data is gathered to analyze time effectiveness, accuracy and payback of the software. Data from seventy part models is recorded to study the time experiment, and data from fifty part models is used to study the accuracy and consistency. Data is analyzed by calculating mean, standard deviation, and test of hypothesis. The results indicate that the software is faster than the traditional quoting system; however, the payback point is high. Also, results show the software has a smaller average time-to-manufacture percentage difference between the automated system and the actual time-to-manufacture (TTM) compared to the percentage difference between the traditional’s TTM and actual TTMs, and this difference is statistically significant. The standard deviation for the automated system is also less implying better consistency

An integrated approach for remanufacturing job shop scheduling with routing alternatives.

Remanufacturing is a practice of growing importance due to increasing environmental awareness and regulations. However, the stochastic natures inherent in the remanufacturing processes complicate its scheduling. This paper undertakes the challenge and presents a remanufacturing job shop scheduling approach by integrating alternative routing assignment and machine resource dispatching. A colored timed Petri net is introduced to model the dynamics of remanufacturing process, such as various process routings, uncertain operation times for cores, and machine resource conflicts. With the color attributes in Petri nets, two types of decision points, recovery routing selection and resource dispatching, are introduced and linked with places in CTPN model. With time attributes in Petri nets, the temporal aspect of recovery operations for cores as well as the evolution dynamics in cores\u27 operational stages is mathematically analyzed. A hybrid meta-heuristic algorithm embedded scheduling strategy over CTPN is proposed to search for the optimal recovery routings for worn cores and their recovery operation sequences on workstations, in minimizing the total production cost. The approach is demonstrated through the remanufacturing of used machine tool and its effectiveness is compared against another two cases: baseline case with fixed recovery process routings and case 2 using standard SA/MST

Improving the Relevance of Cyber Incident Notification for Mission Assurance

Military organizations have embedded Information and Communication Technology (ICT) into their core mission processes as a means to increase operational efficiency, improve decision making quality, and shorten the kill chain. This dependence can place the mission at risk when the loss, corruption, or degradation of the confidentiality, integrity, and/or availability of a critical information resource occurs. Since the accuracy, conciseness, and timeliness of the information used in decision making processes dramatically impacts the quality of command decisions, and hence, the operational mission outcome; the recognition, quantification, and documentation of critical mission-information resource dependencies is essential for the organization to gain a true appreciation of its operational risk. This research identifies existing decision support systems and evaluates their capabilities as a means for capturing, maintaining and communicating mission-to-information resource dependency information in a timely and relevant manner to assure mission operations. This thesis answers the following research question: Which decision support technology is the best candidate for use in a cyber incident notification system to overcome limitations identified in the existing United States Air Force cyber incident notification process

Doctor of Philosophy

dissertationMicroplasmas are currently used in displays, two-terminal breakdown switches, light sources, and medical instruments. They can also be used in miniaturized particle accelerators, micro-X-ray generators, UV and extreme UV sources, gas sensors, and in micropropulsion thrusters. They are also excellent candidates for applications in harsh environments that usually lead to the breakdown of silicon electronics. Here we develop their unique applications in X-band microwave analog and digital devices and circuits. To enable these applications, we identified a breakdown region, called sub-Paschen regime that enables generation of atmospheric plasmas at low voltages. The sub-Paschen regime, involves devices with a breakdown gap below 10 m in 1 atmosphere in air. This newly discovered operation regime enabled us to design plasma devices with relatively low operation voltages of 50-100 V. We developed microplasma devices similar to metal oxide semiconductor field effect transistors (MOSFETs) with drain, source, and gate regions that used plasma channels for switching or amplification. The gate field effect was successfully tested under both direct current (dc) and alternating current (ac) excitations. A drain current modulation frequency up to 7 GHz was obtained. Additionally, we implemented logic gates with microplasma devices to realize simple Boolean logic operations including OR, AND, NOT, and XOR. The gates were then combined to obtain a 1-bit half-adder circuit. The MOPFET developed in this work achieved 3x reduction in the breakdown (device turn-on) voltage by operating in the sub-Paschen regime. In addition to the scaling in breakdown voltage, the microplasma field effect transistors (MOPFETs) are at least 50x smaller compared to plasma transistors reported in the past. The smallest MOPFET used in this work had a source-drain gap of 1 μm and showed unprecedented functionalities derived from plasmas at a microscale

A case study on Application of FUZZY logic in Electrical Discharge Machining(EDM)

Electrical Discharge Machining (EDM) is one of the most accurate manufacturing processes available for creating complex or simple shapes and geometries within parts and assemblies. EDM works by eroding material in the path of electrical discharges that form an arc between an electrode tool and the work piece. EDM manufacturing is quite affordable and a very desirable manufacturing process when low counts or high accuracy is required. Turn around time can be fast and depends on manufacturer back log. The EDM system consists of a shaped tool or wire electrode, and the part. The part is connected to a power supply. Sometimes to create a potential difference between the work piece and tool, the work piece is immersed in a dielectric (electrically non-conducting) fluid which is circulated to flush away debris

Power Generation by Harvesting Ambient Energy with a Micro-Electromagnetic Generator

This thesis investigated the potential power output of a micro-electromagnetic generator fabricated using typical microfabrication materials and techniques. The design was based on a desire to free bio-implanted or remote electronic devices from batteries and their finite power supplies. A micro-electromagnetic generator could harvest energy from the ambient environment and power such devices indefinitely. Designs for the stator coil and rotor magnet components of the generator were optimized to produce maximum current density based upon electromagnetic theory. The relative orientation of the coil to the rotor and material selection for each component were considered. Coils were fabricated using low-resistance gold. A method for overlaying two evaporated gold wires was devised and successfully fabricated in order to avoid side-wall thinning of the coils which has been shown to lead to high resistivities. Rotors were made with nickel, a ferromagnetic material. The required parameters for reduced stress plating using a nickel electroplating bath were investigated in order to pattern and deposit nickel for the rotors. Once fabricated, the rotors were magnetized through the use of an electromagnet. In addition, a testing apparatus that provided precise alignment, a method of rotation to simulate operational functionality, and power measurement capabilities was designed and assembled. Testing of the magnets showed that the nickel rotors were able to be highly magnetized when placed near a strong field. However, upon removal from the field the magnetization quickly dissipated. It was determined that the coercivity, or magnetic hardness, of electroplated nickel was too low for the rotor magnets to retain a field for any appreciable amount of time. Testing of the micro-generator revealed that power output did not exceed 2 nA, which was expected given that the magnetic rotors did not retain their flux density. It was shown that nickel does not maintain the flux density required for a micro-electromagnetic generator and different materials should be investigated

Reasonable Precaution for the Individual

(Excerpt) This Article has four parts. In Part I, I introduce the question to be explored and describe Barbara Fried\u27s challenge to any attempt to answer that question without summing costs and benefits across persons. Part II responds directly to Fried\u27s challenge, presenting the individualized feasibility principle as a viable, nonaggregative interpretation of reasonable precaution. In Part III, I explore the theoretical underpinnings of the IFP, drawing on a theory of normative ethics known as ex ante contractualism. Part IV concludes

Partner selection for reverse logistics centres in green supply chains: a fuzzy artificial immune optimisation approach

The design of reverse logistics networks has now emerged as a major issue for manufacturers, not only in developed countries where legislation and societal pressures are strong, but also in developing countries where the adoption of reverse logistics practices may offer a competitive advantage. This paper presents a new model for partner selection for reverse logistic centres in green supply chains. The model offers three advantages. Firstly, it enables economic, environment, and social factors to be considered simultaneously. Secondly, by integrating fuzzy set theory and artificial immune optimization technology, it enables both quantitative and qualitative criteria to be considered simultaneously throughout the whole decision-making process. Thirdly, it extends the flat criteria structure for partner selection evaluation for reverse logistics centres to the more suitable hierarchy structure. The applicability of the model is demonstrated by means of an empirical application based on data from a Chinese electronic equipment and instruments manufacturing company

Carbon Nanotubes

Since their discovery in 1991, carbon nanotubes have been considered as one of the most promising materials for a wide range of applications, in virtue of their outstanding properties. During the last two decades, both single-walled and multi-walled CNTs probably represented the hottest research topic concerning materials science, equally from a fundamental and from an applicative point of view. There is a prevailing opinion among the research community that CNTs are now ready for application in everyday world. This book provides an (obviously not exhaustive) overview on some of the amazing possible applications of CNT-based materials in the near future