Process improvement and inventory management using value stream mapping in a biopharmaceutical environment

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and, (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; in conjunction with the Leaders for Global Operations Program at MIT, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (p. 73-75).This thesis describes the formulation of short-term and mid-term operational excellence strategies through the use of value stream mapping. It is shown that many interconnected issues form a backdrop for seemingly independent "symptomatic issues" or issues that can be seen readily on the surface because of their significant financial or organizational impacts. These underlying issues indicate organizational improvement projects are necessary in the short term to create an environment conducive to sustaining results stemming from projects addressing the surface issues. One example of a surface issue is that of scheduling where the problem can be readily seen with blockages, starvation, and long cycle times, but must be solved with organizational and other fundamental improvements for improvements to be sustainable. Also presented is a case study showing a root cause and financial analysis relating to the capabilities of the aseptic filling process. The value stream mapping analysis led to recommendations of working on fundamental organizational, communication, and cultural issues to create a strong foundation for improvement projects on more visible projects.by Zachary Wolf.M.B.A.S.M

Undulator Field Integral Measurements

The LCLS undulator field integrals must be very small so that the beam trajectory slope and offset stay within tolerance. In order to make accurate measurements of the small field integrals, a long coil will be used. This note describes the design of the coil measurement system

A Vibrating Wire System For Quadrupole Fiducialization

A vibrating wire system is being developed to fiducialize the quadrupoles between undulator segments in the LCLS. This note provides a detailed analysis of the system. The LCLS will have quadrupoles between the undulator segments to keep the electron beam focused. If the quadrupoles are not centered on the beam axis, the beam will receive transverse kicks, causing it to deviate from the undulator axis. Beam based alignment will be used to move the quadrupoles onto a straight line, but an initial, conventional alignment must place the quadrupole centers on a straight line to 100 {micro}m. In the fiducialization step of the initial alignment, the position of the center of the quadrupole is measured relative to tooling balls on the outside of the quadrupole. The alignment crews then use the tooling balls to place the magnet in the tunnel. The required error on the location of the quadrupole center relative to the tooling balls must be less than 25 {micro}m. In this note, we analyze a system under construction for the quadrupole fiducialization. The system uses the vibrating wire technique to position a wire onto the quadrupole magnetic axis. The wire position is then related to tooling balls using wire position detectors. The tooling balls on the wire position detectors are finally related to tooling balls on the quadrupole to perform the fiducialization. The total 25 {micro}m fiducialization error must be divided between these three steps. The wire must be positioned onto the quadrupole magnetic axis to within 10 {micro}m, the wire position must be measured relative to tooling balls on the wire position detectors to within 15 {micro}m, and tooling balls on the wire position detectors must be related to tooling balls on the quadrupole to within 10 {micro}m. The techniques used in these three steps will be discussed. The note begins by discussing various quadrupole fiducialization techniques used in the past and discusses why the vibrating wire technique is our method of choice. We then give an overview of the measurement system showing how the vibrating wire is positioned onto the quadrupole axis, how the wire position detectors locate the wire relative to tooling balls without touching the wire, and how the tooling ball positions are all measured. The novel feature of this system is the vibrating wire which we discuss in depth. We analyze the wire dynamics and calculate the expected sensitivity of the system. The note should be an aid in debugging the system by providing calculations to compare measurements to

High Reliability Prototype Quadrupole for the Next Linear Collider

Abstract-- The Next Linear Collider (NLC) will require over 5600 magnets, each of which must be highly reliable and/or quickly repairable in order that the NLC reach its 85 % overall availability goal. A multidiscipline engineering team was assembled at SLAC to develop a more reliable electromagnet design than historically had been achieved at SLAC. This team carried out a Failure Mode and Effects Analysis (FMEA) on a standard SLAC quadrupole magnet system. They overcame a number of longstanding design prejudices, producing 10 major design changes. This paper describes how a prototype magnet was constructed and the extensive testing carried out on it to prove full functionality with an improvement in reliability. The magnet’s fabrication cost will be compared to the cost of a magnet with the same requirements made in the historic SLAC way. The NLC will use over 1600 of these 12.7 mm bor

Conservation Status Assessment of the Egg-mimic Darter (Percidae: \u3ci\u3eEtheostoma pseudovulatum\u3c/i\u3e) Using a Multi-faceted Approach

The imperiled Egg-mimic Darter (Etheostoma pseudovulatum) is a headwater-adapted fish restricted to an area less than 1000 km2 in Tennessee. It is found in only six tributaries of the Duck River and the large, mainstem of this system may act as a barrier to dispersal, restricting population connectivity. The only status assessment of this species was over two decades ago; genetic diversity and the degree of population connectivity have never been evaluated. We conducted a conservation status assessment using a multi-faceted approach to better inform conservation management plans, including examining its current distribution, assessing habitat quality, estimating abundance, population size and haplotype diversity, and evaluating historical population connectivity. Surveys were conducted in spring and fall (2014) and population size was estimated using the Petersen mark-recapture method at a subset of localities, which were then regressed to obtain population estimates at all localities. Haplotype diversity and population connectivity were examined using the mitochondrial ND2 gene. The Egg-mimic Darter was present at all localities and was relatively abundant, comparable to historical observations. Habitat quality did not appear to be substantially degraded. Overall haplotype and nucleotide diversity were low compared to widespread darters and comparable to other imperiled darters; however, demographic analyses indicated the species has remained stable over contemporary and historical timeframes. The Egg-mimic Darter has likely maintained gene flow historically at five of the six tributary systems, suggesting the mainstem Duck has not been a long-standing barrier to dispersal. One haplotype was shared across all tributary systems except Beaverdam Creek, which had a largely unique assemblage of haplotypes. Overall, the conservation status of the Egg-mimic Darter appears to be stable. However, we recommend regular monitoring with special consideration given to smaller tributary systems and the genetically distinct Beaverdam Creek population. Even though there was evidence of historical population connectivity, the risk of local extirpation remains, considering the small population sizes in several tributary systems. We also recommend assessments of contemporary genetic structure and population connectivity

High-efficiency Silicon Heterojunction Solar Cells: A Review

Silicon heterojunction solar cells consist of thin amorphous silicon layers deposited on crystalline silicon wafers. This design enables energy conversion efficiencies above 20% at the industrial production level. The key feature of this technology is that the metal contacts, which are highly recombination active in traditional, diffused-junction cells, are electronically separated from the absorber by insertion of a wider bandgap layer. This enables the record open-circuit voltages typically associated with heterojunction devices without the need for expensive patterning techniques. This article reviews the salient points of this technology. First, we briefly elucidate device characteristics. This is followed by a discussion of each processing step, device operation, and device stability and industrial upscaling, including the fabrication of solar cells with energy-conversion efficiencies over 21%. Finally, future trends are pointed ou

Reference Undulator Measurement Results

The LCLS reference undulator has been measured 22 times during the course of undulator tuning. These measurements provide estimates of various statistical errors. This note gives a summary of the reference undulator measurements and it provides estimates of the undulator tuning errors. We measured the reference undulator many times during the tuning of the LCLS undulators. These data sets give estimates of the random errors in the tuned undulators. The measured trajectories in the reference undulator are stable and straight to within {+-}2 {micro}m. Changes in the phase errors are less than {+-}2 deg between data sets. The phase advance in the cell varies by less than {+-}2 deg between data sets. The rms variation between data sets of the first integral of B{sub x} is 9.98 {micro}Tm, and the rms variation of the second integral of B{sub x} is 17.4 {micro}Tm{sup 2}. The rms variation of the first integral of B{sub y} is 6.65 {micro}Tm, and the rms variation of the second integral of B{sub y} is 12.3 {micro}Tm{sup 2}. The rms variation of the x-position of the fiducialized beam axis is 35 {micro}m in the final production run This corresponds to an rms uncertainty in the K value of {Delta}K/K = 2.7 x 10{sup -5}. The rms variation of the y-position of the fiducialized beam axis is 4 {micro}m in the final production run

Undulator Changes Due to Temperature Excursions

The temperature of the LCLS undulators has not been controlled during storage. The effects of the temperature excursions are documented in this note. After a number of LCLS undulators were tuned, fiducialized, and placed in storage anticipating their use, a test was made to ensure that their properties had not changed. The test revealed, however, that indeed the undulators had changed. Detailed study of this problem followed. We now believe that the gap of the undulators changes permanently when the undulators go through temperature excursions. We have tested the other possible cause, transportation, and do not see gap changes. In this note, we document how the undulators have changed since they were originally tuned. The undulators were tuned and fiducialized in the Magnetic Measurement Facility (MMF). Afterward, many of them (approximately 18) were taken to building 750 for storage during summer and fall 2007. Building 750 had no temperature control. The undulator temperatures went from 20 C, used for tuning, down to approximately 11 C during the winter. In January 2008, three of the undulators were brought back to the MMF for a check. All three undulators showed similar changes. Trajectories, phases, and most undulator properties stayed the same, but the fiducialization (beam axis position relative to tooling balls on the undulator) had changed. Further investigation showed that the undulator gap was altered in a periodic way along the magnetic axis with a net average gap change causing the fiducialization change. A new storage location in building 33 was found and future undulators were placed there. A failure in the temperature control, however, caused the undulators to get too hot. Again the gap changed, but with a different periodic pattern. This note documents the measured changes in the undulators. In particular, it shows the detailed history of undulator 39 which went through both negative and positive temperature excursions

Probing Quasar Viewing Angle with the Variability Structure Function

Given the anisotropic emission from quasar accretion discs, their viewing angle affects estimates of the quasar luminosity, black-hole mass and Eddington ratio. Discs appear overluminous when viewed pole-on and underluminous when viewed at high inclination. In radio-quiet quasars, the viewing angle is usually unknown, although spectroscopic indicators have been proposed. Here, we use a recently discovered universality in the variability structure function (SF) of quasar light curves (LCs), where all quasars show the same SF when clocks run in units of orbital timescale. As an offset from the mean relation can be caused by incorrect orbital timescales and thus incorrect luminosities, we correlate these offsets with suggested inclination indicators. We derive SFs from NASA/ATLAS LCs spanning $\sim 6$ years of observation, using a sample of 183 luminous quasars with measured H$\beta$ lines as well as 753 quasars with CIV and MgII lines. Starting from the proposed orientation indicators, we expect quasars with narrower H$\beta$ lines and with more blueshifted CIV lines to be viewed more pole-on and thus appear overluminous. In contrast, our SF analysis finds that presumed pole-on discs appear underluminous, consistently for both line indicators. We discuss possible explanations for the behaviour of quasars with highly blueshifted CIV lines irrespective of inclination angle, including dusty outflows that might render the accretion disc underluminous and flatter disc temperature profiles with longer orbital timescales than in thin-disc models but reach no satisfying conclusion.Comment: 15 pages, 10 figures, Accepted for publication in MNRA