Variable Powder Flow Rate Control in Laser Metal Deposition Processes

This paper proposes a novel technique, called Variable Powder Flow Rate Control (VPFRC), for the regulation of powder flow rate in laser metal deposition processes. The idea of VPFRC is to adjust the powder flow rate to maintain a uniform powder deposition per unit length even when disturbances occur (e.g., the motion system accelerates and decelerates). Dynamic models of the powder delivery system motor and the powder transport system (i.e., five–meter pipe, powder dispenser, and cladding head) are first constructed. A general tracking controller is then designed to track variable powder flow rate references. Since the powder flow rate at the nozzle exit cannot be directly measured, it is estimated using the powder transport system model. The input to this model is the DC motor rotation speed, which is estimated on–line using a Kalman filter. Experiments are conducted to examine the performance of the proposed control methodology. The experimental results demonstrate that VPFRC is successful in maintaining a uniform track morphology, even when the motion control system accelerates and decelerates.Mechanical Engineerin

Development of a Melt Pool Tracking Vision System for Laser Deposition

This paper chronicles the development of a vision system for tracking melt pool morphology in the laser metal deposition process. This development is to augment an existing temperature feedback control system. Monitoring both the temperature and shape of the melt pool is necessary because of the effects of local geometry on the cooling rate at the melt pool. Temperature feedback alone cannot accommodate this effect without complex process planning. The vision system’s hardware, software, and integration into the laser deposition system’s controller is detailed in this paper. Preliminary testing and the effects on deposition quality is also discussed.Mechanical Engineerin

Efficacy and Safety of Atorvastatin in South Asian Patients with Dyslipidemia: An Open Label Noncomparative Pilot Study

Jeetesh V Patel1, Sandeep Gupta2, Frank Lie3, Elizabeth A Hughes11Sandwell and West Birmingham Hospitals NHS Trust, West Bromwich, UK; 2Whipps Cross and St Bartholomew’s Hospitals; and 3Whipps Cross University Hospital, London, UKBackground: Rates of coronary heart disease (CHD) mortality are 40% higher amongst South Asian men and women living in the UK compared with the general UK population. Despite an established excess CHD risk, little is known of the efficacy and safety of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins) amongst South Asian migrants.Methods and results: Hyperlipidemic South Asian patients (raised or uncontrolled lowdensity lipoprotein cholesterol [LDL-C]) were recruited from two UK centers (n = 33). After a five-week period, which included dietary advice, patients received atorvastatin 10 mg/d for five weeks to achieve a target LDL-C goal of < 3.0 mmol/L, titrated to 20 mg, 40 mg, or 80 mg for a further 12 weeks as required. Significant reductions in LDL-C levels from baseline were observed after 4 weeks’ and 17 weeks’ treatment with atorvastatin (≥ 33.6%; 26.0, 41.2). Overall, 81% (95% confidence interval [CI]: 62.5, 92.6%) achieved the target LDL-C after 4 weeks’ treatment with 10 mg atorvastatin. Titration to a dose of more than 20 mg was required in only one patient (40 mg) at any point during the study. Nineteen patients reported at least one adverse event during the study; the majority were mild in severity and considered unrelated to atorvastatin.Conclusions: Atorvastatin was effective in achieving target lipid levels and was well tolerated. Statin therapy for high-risk South Asian individuals is likely to benefit CHD outcomes, although further and larger prospective trials are required.Keywords: hyperlipidemia, lipids, cholesterol, dyslipidemia, statins, coronary heart disease, South Asian

Layer-to-Layer Height Control for Laser Metal Deposition Processes

A Laser Metal Deposition (LMD) height controller design methodology is presented in this paper. The height controller utilizes the Particle Swarm Optimization (PSO) algorithm to estimate model parameters between layers using measured temperature and track height profiles. The process model parameters for the next layer are then predicted using Exponentially Weighted Moving Average (EWMA). Using the predicted model, the powder flow rate reference profile, which will produce the desired layer height reference, is then generated using Iterative Learning Control (ILC). The model parameter estimation capability is tested using a four-layer deposition. The results demonstrate the simulation based upon estimated process parameters matches the experimental results quite well. Simulation study also shows that the methodology described above works well in producing the reference layer height

Direct 3D Layer Metal Deposition

Multi-axis slicing for solid freeform fabrication (SFF) manufacturing processes can yield non-uniform thickness layers, or 3D layers. Using the traditional parallel layer construction approach to build such a layer leads to a staircase which requires machining or other post processing to form the desired shape. This paper presents a direct 3D layer deposition approach. This approach uses an empirical model to predict the layer thickness based on experimental data. The toolpath between layers is not parallel; instead, it follows the final shape of the designed geometry and the distance between the toolpath in the adjacent layers varies at different locations. Directly depositing a 3D layer not only eliminates the staircase effect, but also improves the manufacturing efficiency by shortening the deposition and machining times. Experiments are conducted that demonstrate these advantages. Thus, the 3D deposition method is a beneficial addition to the traditional parallel deposition method

Krisehåndteringsprosesser i Hæren knyttet til internasjonale operasjoner: Mellomlanding – forebyggende krisehåndtering, anerkjennelse og ivaretakelse - Mellomlanding - arena for feedback av informasjoner til gjenbruk i fremtidig produksjon av stridsevne i Hæren

Prosjektoppgave Krisehåndtering, 2012Innledning: Forsvaret har i ”nyere” tid bidratt med soldater til internasjonale operasjoner fra UNIFIL (United Nations Interim Forces in Lebanon) siden våren 1978 via en mengde andre internasjonale operasjoner frem til dagens bidrag i Afghanistan. Totalt er ca 100 000 personer å regne som veteraner i Norge. En veteran er en soldat med erfaring fra operasjoner både nasjonalt og internasjonalt. Inspektøren for Veterantjenesten, generalmajor Mood definerer veteraner slik: ”Våre veteraner har praktisk erfaring med å løse krevende oppdrag i en kompleks situasjon under tidspress i møte med vanskelige verdispørsmål. Soldatenes erfaring og kompetanse skiller seier fra nederlag, og det innebærer større belastning på menneskene” (http://forsvaret.no/veteraner/veterantjenesten/Sider/hva-er-veteran.aspx) 8. mai 2012. Erfaringene og kompetansen innebærer også en høy grad av beredskap i forhold til omgivelsene i operasjonsområdet. Ved hjemkomst er opplevelsen av å være fysisk i Norge, men mentalt i et tidligere operasjonsområde er utvilsomt svært slitsom å leve med. Den høye mentale beredskapen ovenfor plutselige påvirkninger som kan skade eller drepe, er ikke blitt deaktivert. De fleste av oss har sett veteraner på tv, som flere tiår etter at de kom hjem forteller om den bråe overgangen mellom operasjonsområdet og Norge. De forteller om sine handlinger som å kaste seg i skjul og dekning ved skarpe smell, eller at de finner det naturlig å lage stillinger av sandsekker på terrassen sin. Dette er stressreaksjoner som kan utvikle seg til post traumatisk stressyndrom (PTSD), dette er en diagnose som det har tatt lang tid å erkjenne som en sykdom eller skade som følge av opplevelsene i operasjonsområdet. Hvordan kan Forsvaret ivareta sine veteraner på en måte hvor de føler sin egen innsats og erfaring blir verdsatt av Forsvaret og det øvrige samfunn. Vi har valgt å se nærmere på et helt nytt konsept innen krisehåndtering i Hæren, knyttet til internasjonale operasjoner. Konseptet kalles ”Mellomlanding” og er forankret i Regjeringens handlingsplan (RHP) som tiltak nr 48. Hensikten med ”Mellomlandingen” er å skjerme personellet for å gjennomføre debrifingsprosesser, dette skal gi mulighet til å kunne tilpasse seg fra ”operasjonsmiljøet” og tilbake til ”normalmiljøet”. Kan Hæren og Forsvaret dra nytte av et slikt konsept, ved å lage en vinn, vinn situasjon

Propagation of states from BPEL process instances to Chevron models

This report describes key aspects of a code library that we developed for the purpose of state propagation for business process monitoring on different levels of abstraction. The library supports the propagation of execution states of process instances based on the Business Process Execution Language (BPEL) to process models specified in the "Chevron" language. The Chevron language is an abstract, non-executable process language that we especially designed for abstract process instance monitoring purposes. The look and feel of this graphical language is similar to value chains. The basic concept of the Chevron language is based on Chevron-shaped charts which can be modeled in Microsoft PowerPoint to describe a process on a high level of abstraction. We aim at enabling the use of high-level process in order to monitor the instance status of a much more detailed, lower-level model. We describe the overall procedure of performing state projections along a concrete scenario. We describe a format for state propagation rules which define how the status of activities of a BPEL process instance should be projected to the elements of a Chevron model. We present a format to serialize process models in the Chevron language. We present a graphical template based on Scalable Vector Graphics (SVG) which we employ to render a stateful Chevron model graphically. The Chevron language is just one language to be used for abstract representation of process instances. However, the approach for state propagation is generic and can be applied for other languages, too

The Relative Composition of the Inflammatory Infiltrate as an Additional Tool for Synovial Tissue Classification

10.1371/journal.pone.0072494PLoS ONE88-POLN

Quality of vision and vision-related quality of life after Descemet membrane endothelial keratoplasty:a randomized clinical trial

PURPOSE: To compare quality of vision and vision‐related quality of life (QOL) in patients undergoing Descemet membrane endothelial keratoplasty (DMEK) or ultrathin Descemet stripping automated endothelial keratoplasty (DSAEK). METHODS: Fifty‐four eyes of 54 patients with Fuchs' dystrophy from six corneal clinics in the Netherlands were randomized to DMEK or ultrathin DSAEK and examined preoperatively, and 3, 6 and 12 months postoperatively. Main outcome measures were corneal higher‐order aberrations (HOAs), contrast sensitivity, straylight and vision‐related QOL. RESULTS: Posterior corneal HOAs decreased after DMEK and increased after ultrathin DSAEK (p ≤ 0.001) 3 months after surgery and correlated positively with best spectacle‐corrected visual acuity (12 months: r = 0.29, p = 0.04). Anterior and total corneal HOAs did not differ significantly between both techniques at any time point. Contrast sensitivity was better (p = 0.01), and straylight was lower (p = 0.01) 3 months after DMEK compared with ultrathin DSAEK; 95% confidence interval [CI] of log(cs) 1.10–1.35 versus 95% CI: 0.84 to 1.12, and 95% CI: log(s) 1.18 to 1.43 versus 95% CI: 1.41 to 1.66, respectively. Both were comparable at later time points. Vision‐related QOL (scale 0–100) did not differ significantly between both groups at any time point and improved significantly at 3 months (β = 12 [95% CI: 7 to 16]; p < 0.001), and subsequently between 3 and 12 months (β = 5 [95% CI: 0 to 9]; p = 0.06). CONCLUSIONS: Descemet membrane endothelial keratoplasty (DMEK) results in lower posterior corneal HOAs compared with ultrathin DSAEK. Contrast sensitivity and straylight recover faster after DMEK but reach similar levels with both techniques at 1 year. Vision‐related QOL improved significantly after surgery, but did not differ between both techniques

South-South Cooperation and Neo-liberal hegemony in a Post-aid world

YesSouth-South Cooperation SSC) has returned as a significant trope in the contemporary rhetoric of the aid industry. We compare the way that the idea of SSC is being currently constructed. In the 1960s and 1970s, SSC was discussed as constituting a challenge to the ideological dominance of the global north, presented initially as a counter-hegemonic challenge to neo-colonialism. Currently it is framed similarly as a challenge to neoliberalism. However, the current iteration of SSC differs fundamentally from the first round in the early 1970s, largely because of differences in assumptions about who is co-operating with whom and to what end, in the context of SSC. These differences are significant for the material practice of SSC and the ideological function of SSC rhetoric