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NUMERICAL MODELING OF LASER IRRADIATION CONSIDERING FOCAL POSITION DURING FIBER LASER CUTTING PROCESS

NUMERICAL MODELING OF LASER IRRADIATION CONSIDERING FOCAL POSITION DURING FIBER LASER CUTTING PROCESS

The laser cutting excels in applications requiring high productivity, a high edge quality and a minimum waste, due to the fast and precise cutting process. In the last few years, the rapid development of high power fiber lasers provides more efficient, robust new technologies for materials process. A beam of coherent monochromatic light of high power density is focused on to the work piece surface causing it to vaporize locally. The material then leaves the surface in the vaporized or liquid state at high velocity [1, 2, 3]. But complete understanding of laser interaction with materials is still a matter of trials and adjustments. The real physical processes of laser beam interaction (drilling, cutting, or welding) with materials are very complex. Problem of laser interaction with materials presents many difficulties, both from modeling as well as from experimental sides. One would expect a reasonable description of the main phenomena occurring during laser interaction, but this is complicated because many of physical processes equally contribute to the development of conservation equations, producing draw back because of a great complexity of the equations to be solved. In most instances, this leads to formulation of a model needed to be solved numerically. A lack of pertinent experimental data to compare with, forces one to simplify some equations and use previous analytical and computational work done in this filed [4, 5]. Through this research work one have deduce numerical model of laser irradiation considering focal position during fiber laser cutting process.
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Remote Laser Welding with High Power Fiber Lasers

Remote Laser Welding with High Power Fiber Lasers

This paper studied remote laser welding with fiber lasers. Remote fiber laser welding is a versatile technology with a promising future. The process has been adopted by the automotive industry due to its advantageous characteris- tics, such as high productivity, high flexibility, and low operational costs. The scanner system is one of the most important requirements for remote fiber laser welding. However, to make a sound weld, a number of process parameters, such as beam quality, laser power, welding speed, shielding gas supply, and focal position have to be taken into account in remote laser welding.
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Acoustic Emission Analysis of Dissimilar Laser welds of Aluminium and Polyamide 6 6

Acoustic Emission Analysis of Dissimilar Laser welds of Aluminium and Polyamide 6 6

Sample 2 was welded without any inert gas. The missing gas had no influence on the narrow characteristic of the hit-belt. During welding of specimen 3 the inert gas was also deactivated and the vertical focal position was moved into the aluminium surface. In comparison to the reference sample 1, the laser beam was focused on a higher level in sample 3. Due to that difference, the spot diameter on the surface decreased and the heat density increased. More heat got assumable induced. Figure 9 indicates this causality between the heat input and the formation of bubbles. As a result of the formation of gas bubbles, some gas channels occurred. Their extension reached actually the surface of the plastic sample.
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Experimental and numerical study on the influence of the laser hybrid parameters in partial penetration welding on the solidification cracking in the weld root

Experimental and numerical study on the influence of the laser hybrid parameters in partial penetration welding on the solidification cracking in the weld root

cracks for high-power laser-based welding processes. The center of the weld solidifies at last and therefore contains large columnar-shaped grains, which impinge on each other. Thereby, voids between the grains arise, which cannot be filled with the molten filler being added from above. Numerical and experimental analyses by Bakir et al. [14] show that a bulging region is created in the centerline due to the Marangoni vortex on the sur- faces. Solidification cracks are expected in the bulging region. This phenomenon is more frequent for partial pen- etration welds. Gebhardt et al. [15, 16] show that cracks are formed close to the weld root. As the wire feed speed increased, the number of cracks could be reduced. Growth in penetration depth due to an increase of the laser power showed the opposite effect. The welding speed, which was variated in a range between 1.7 and 3.2 m min − 1 , showed no significant influence on the crack number. Schaefer et al. [17] demonstrated that crack formation can be eliminated for partial penetration HLAW using a higher optical magnification of 2.67. They also showed that the focal position of the laser beam affected the melt flow during laser welding of steel, the keyhole shape, and the weld pool geometry [18]. However, these modifica- tions of the melt flow were mainly on the upper half of the weld pool.
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Novel enhancement of HVOF thermal sprayed nanostructured WC-12Co / inconel-625 coatings for tribocorrosion applications

Novel enhancement of HVOF thermal sprayed nanostructured WC-12Co / inconel-625 coatings for tribocorrosion applications

For the mixed coating, the Perturbation plot (shown in Figure 5-62), shows the surface roughness to reduced at lower energy levels; then, as the energy rises by increasing the laser power or lowering the focal position, the surface roughness increases. However, laser power has a major effect on roughness compared to the other two factors at their maximises. For the focal position, the surface roughness seems different. As previously explained, increasing the focal position will lower the energy density; consequently, the surface roughness for the mixed coating shows a slight reduction and increased focal position levels/beam size. This outcome could be further clarified by presenting the significant differences between the two focal positions that provided the smallest (+35 mm) and largest beam size (+45 mm) in their interaction via applying laser power to the mixed-coating’s surface roughness, as shown in Figure 5-63. However, the higher impact of the focal position for the laser treated monomial nWC-12Co coating clearly increases surface roughness or decreases it for the compressed mixed coating. A similar interaction plot shows the melt pool geometry static analyses between the laser power and the focal position, which could be attributed to findings reported by Yasa et al. [121], who found that by using a bigger laser beam, the number of laser tracks along the surface will be smaller; subsequently, the number of transaction regions between the tracks that formed valleys will be minimised and create a smother surface.
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The Routine Integration of Raman Spectroscopy into the Forensic Examination of Black Cotton

The Routine Integration of Raman Spectroscopy into the Forensic Examination of Black Cotton

Page | 39 focal position. The sample focal plane as seen in Figure 3.17 was applied to all Raman analyses of the samples taken in the shade variation database as this yielded better results when experiments were being run for the black/grey cotton trial database. All samples that were taken prior to sun exposure and mounted on glass, displayed well resolved spectra that corresponded with Reactive black dye. These results were of meaningful quality, as they were similar in pattern to, and shared features with, the samples that were mounted on aluminium foil. An example of this can be seen in Figure 3.19. The original garment that samples were taken from was unwashed, and bought brand new in packaging. It can be assumed that the dye concentration was at its highest and therefore the colour was at its most intense. The quality of spectra taken from samples that had no prior sun exposure and were mounted on glass was dependent on this dye intensity. All of these glass mounted samples provided meaningful spectra when compared with those mounted on aluminium.
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Preparation and 3D Tracking of Catalytic Swimming Devices

Preparation and 3D Tracking of Catalytic Swimming Devices

We report a method to prepare catalytically active Janus colloids that "swim" in fluids and describe how to determine their 3D motion using fluorescence microscopy. One commonly deployed method for catalytically active colloids to produce enhanced motion is via an asymmetrical distribution of catalyst. Here this is achieved by spin coating a dispersed layer of fluorescent polymeric colloids onto a flat planar substrate, and then using directional platinum vapor deposition to half coat the exposed colloid surface, making a two faced "Janus" structure. The Janus colloids are then re-suspended from the planar substrate into an aqueous solution containing hydrogen peroxide. Hydrogen peroxide serves as a fuel for the platinum catalyst, which is decomposed into water and oxygen, but only on one side of the colloid. The asymmetry results in gradients that produce enhanced motion, or "swimming". A fluorescence microscope, together with a video camera is used to record the motion of individual colloids. The center of the fluorescent emission is found using image analysis to provide an x and y coordinate for each frame of the video. While keeping the microscope focal position fixed, the fluorescence emission from the colloid produces a characteristic concentric ring pattern which is subject to image analysis to determine the particles relative z position. In this way 3D trajectories for the swimming colloid are obtained, allowing swimming velocity to be accurately measured, and physical phenomena such as gravitaxis, which may bias the colloids motion to be detected.
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Suriname joint annual report 2008. Calendar year 2007

Suriname joint annual report 2008. Calendar year 2007

Concerning Gender, 25.5% 43 of seats in parliament are now held by women, which is up from 8% in 1990 and 19.6% in 2005. In 2007 Suriname's gender related development index (GDI) ranking was 78, better than its HDI ranking. The World Economic Forum (WEF) Global Gender Gap Index 2007 also placed Suriname a respectable 56 th position out of 128 countries. 33.6% of women aged 15 and over are economically active. In 2007 the Minister of Home Affairs (BIZA) installed the ''Interdepartmental Commission Gender Regulations'' to examine Suriname’s legislation in the context of the Convention on the Elimination of All Forms of Discrimination against Women and the Treaty of Belem do Para. In 2006 a draft bill on the prevention of domestic violence was also presented to the Ministry of Justice and Police is awaiting approval. The Women’s Business Group (WBG) also wants to promote micro-enterprises by women. Established in 1993, the WBG has 350 members and aims to stimulate non-traditional enterprises. Another gender initiative is the EC funded UNIFEM project - Euro 250,000 – which is looking to incorporate gender into national development processes.
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REVIEW FOR FINAL - Waves and Optics 2016.pptx

REVIEW FOR FINAL - Waves and Optics 2016.pptx

If a ray is drawn through the FOCAL POINT , it will be refracted PARALLEL to the principle axis.. Use each focal point ONCE..[r]

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Evaluation of the Commission's Support to Sierra Leone. Country Level Evaluation. Final Report (3rd and final draft). August 2006

Evaluation of the Commission's Support to Sierra Leone. Country Level Evaluation. Final Report (3rd and final draft). August 2006

Envelope B funded interventions, completed with budget line funded projects (EIHRD), effi- ciently supported the peace & reconciliation process during the transition period. Overall, good and useful support projects, delegated to mainly European NSAs, have been funded. However, substantial delays, mainly in preparation, but also in implementation of a good number of interventions, have occurred. Thus, Envelope B funded activities are still under preparation in 2006, more than 6 years after the effective end of the civil war. It seems that, in part, Envelope B funded activities have been prioritised by the Delegation, as they require less input for preparation and monitoring and allow for a higher degree of flexibility in imple- mentation, e. g. the “strategy” is designed and justified by the implementing agency or or- ganisation. Thus, useful work has been done, but it is not (always) covered by the overall country strategy. The inputs in rural development and agriculture funded through the enve- lope B may be useful, but hey are in contradiction to the general EC criteria of concentrating on “focal sectors”.
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COMPETITION, STATUS AND MARKETS

COMPETITION, STATUS AND MARKETS

Figures 7 and 8 are bar plots depicting how the perception of the situation as an opportunity or threat varies depending on the specific combination of relative status of rival and rival’s market commonality with the focal firm. I note that the low-status rival low market commonality combination seems to elicit perceptions of the situation as more of an opportunity than a threat. However, a key distinction between the experiment and the field study is that the experiment does not account for awareness. Based on the theorizing and results from the field study it is unlikely that a firm would be paying significant attention to a rival in this zone. As already noted, even if a focal firm is aware of a rival in this zone, it is unlikely to be watching it closely or even to proceed with classifying the stimulus as a threat or opportunity. The experiment forces a response along those dimensions for all subjects. This may also be the reason that the direct effect of status in perceiving a situation as an opportunity or threat is negative and significant. Despite that, the mediated moderation model receives support. The bar plots for
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The Argos CLS Kalman filter : error structures and state space modelling relative to Fastloc GPS data

The Argos CLS Kalman filter : error structures and state space modelling relative to Fastloc GPS data

We show that the new Argos SRUKF algorithm generates location estimates with accuracies that are often less than 4 km from true positions when compared to concurrently-collected Fas- tloc GPS data, and that these data can be used to reconstruct realistic animal trajectories. Fur- thermore, the quantitative estimates of error provided in the current study can be used as input for numerous location-correction models. Although only two focal animals were used to dem- onstrate the utility of SSM with the new Argos location data, we discussed the relative impor- tance of animal behaviour in determining the quality of track reconstruction. However, we recommend that telemetry users consider the influence of environmental factors, including lat- itudinal coverage of satellites and the effects of temperature on transmitter function with re- spect to the performance of Argos location estimation algorithms and to consider if, in this context, our findings are appropriate to use in their studies.
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Specification. RAD Level 2 Certificate in Vocational Graded Examination in Dance: Intermediate Foundation (Ballet)

Specification. RAD Level 2 Certificate in Vocational Graded Examination in Dance: Intermediate Foundation (Ballet)

Linking Steps: Pas de bourrées devant, derrière, dessus and dessous Changement, changement battu, relevé in 5th position. Focal Step: Assemblés devant, derrière, dessus and dessous[r]

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Mutual dependency grid for stakeholder mapping: a component-based approach to supply chain participant analysis

Mutual dependency grid for stakeholder mapping: a component-based approach to supply chain participant analysis

identification and analysis methods focus on the activities and processes and ignore the artefacts being processed by human beings. By focusing on the outputs of the organisation, an artefact-centric view helps create a network of artefacts, and a component-based structure of the organisation and its supply chain participants. Since the relationship is based on the components, i.e. after the stakeholders are identified, the interdependency between stakeholders and the focal organisation can be measured. Each stakeholder is associated with two types of dependency, namely the stakeholder’s dependency on the focal organisation and the focal organisation’s dependency on the stakeholder. We identify three factors for each type of dependency and propose the equations that calculate the dependency indexes. Once both types of the dependency indexes are calculated, each stakeholder can be placed and categorised into one of the four groups, namely critical stakeholder, mutual benefits stakeholder, replaceable stakeholder, and easy care stakeholder. The mutual dependency grid and the dependency gap analysis, which further investigates the priority of each stakeholder by calculating the weighted dependency gap between the focal organisation and the stakeholder, subsequently help the focal organisation to better understand its stakeholders and manage its stakeholder relationships.
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Focal brain inflammation and autism

Focal brain inflammation and autism

Increasing evidence indicates that brain inflammation is involved in the pathogenesis of neuropsychiatric diseases. Autism spectrum disorders (ASD) are characterized by social and learning disabilities that affect as many as 1/80 children in the USA. There is still no definitive pathogenesis or reliable biomarkers for ASD, thus significantly curtailing the development of effective therapies. Many children with ASD regress at about age 3 years, often after a specific event such as reaction to vaccination, infection, stress or trauma implying some epigenetic triggers, and may constitute a distinct phenotype. ASD children respond disproportionally to stress and are also affected by food and skin allergies. Corticotropin-releasing hormone (CRH) is secreted under stress and together with neurotensin (NT) stimulates mast cells and microglia resulting in focal brain inflammation and neurotoxicity. NT is significantly increased in serum of ASD children along with mitochondrial DNA (mtDNA). NT stimulates mast cell secretion of mtDNA that is misconstrued as an innate pathogen triggering an auto-inflammatory response. The phosphatase and tensin homolog (PTEN) gene mutation, associated with the higher risk of ASD, which leads to hyper-active mammalian target of rapamycin (mTOR) signalling that is crucial for cellular homeostasis. CRH, NT and
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EFFECT OF BISPHENOL- A ON HISTOPATHOLOGY IN LIVER AND BRAIN OF CHICK EMBRYOS

EFFECT OF BISPHENOL- A ON HISTOPATHOLOGY IN LIVER AND BRAIN OF CHICK EMBRYOS

A histopathological section of liver and brain tissues from the experimental groups has been evaluated to study the signs of development of oxidative damage caused in response to BPA toxicity. Mild degenerative changes with micro vesiculation, focal areas of necrosis, karyorrhexis of the nucleus and focal infiltration of inflammatory cells were observed in liver tissue after 24 hours in Group-II and III compared to Group-I in 11 th day BPA injected chick embryos which are in accordance with Tyl et al. (2002) and Yamasaki et al. (2002) who observed chronic hepatic inflammation in rats. Demyelinating hyperemic and degenerative changes were noticed in the brain of BPA injected chick embryos. Similar results were also reported by Gharibi et al. (2013) with BPA treatment. Liver tissue impairment and vacuolation noticed in the present study are in agreement with Venkataswamy et al. (2013) where vacuolation of hepatocytes were more pronounced around the central vein in the developing chick embryos injected with acrylamide.
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Schriefl, Simone
  

(2009):


	Untersuchungen zu Ätiologie und Prognose epileptischer Anfälle bei der Katze.


Dissertation, LMU München: Tierärztliche Fakultät

Schriefl, Simone (2009): Untersuchungen zu Ätiologie und Prognose epileptischer Anfälle bei der Katze. Dissertation, LMU München: Tierärztliche Fakultät

Statistical analyses—Distributions of cats with different seizure etiologies (reactive, symptomatic, or idiopathic) among the various types of seizures (focal, primary focal with secon[r]

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Successful Catheter Ablation of Atrial Tachycardia Originating from the Non coronary Aortic Sinus

Successful Catheter Ablation of Atrial Tachycardia Originating from the Non coronary Aortic Sinus

In this case, VA conduction was absent. The tachycardia was initiated and terminated by incremental atrial pacing and extrastimuli. The tachycardia was reproducibly terminated by a small dose of verapamil without the development of AVN conduction block. On the basis of these findings, the tachycardia mechanism was deter- mined to be due to either micro-re-entry or trig- gered activity. During the tachycardia, the local electrograms recorded from the non-coronary sinus of Valsalva and near the His-bundle region were earlier than those at other sites. The clinical and electrophysiological characteristics of this focal atrial tachycardia were similar to those described in the patients with focal atrial tachy- cardia originating from the non-coronary aortic sinus of Valsalva described by Tada et al. 5 and
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Effect of a photoperiodic green light programme during incubation on embryo development and hatch process

Effect of a photoperiodic green light programme during incubation on embryo development and hatch process

However, the individual hatching time of the light stimulated focal chicks was 3.4 hours 407. earlier than the control focal chicks[r]

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How To Test For Focal Paralysis

How To Test For Focal Paralysis

Peripheral nerve anatomical and molecular changes alter stimulation responses during the percutaneous ap- plication of short and long pulse duration currents over the lesioned nerve and [r]

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