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Search Results: 1 - 10 of 321410 matches for " F. L.;Weingaertner "
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Influence of duty factor on the die-sinking Electrical Discharge Machining of high-strength aluminum alloy under rough machining
Amorim, F. L.;Weingaertner, W. L.;
Journal of the Brazilian Society of Mechanical Sciences , 2002, DOI: 10.1590/S0100-73862002000300007
Abstract: the use of high-strength aluminium alloys as material for injection molding tools to produce small and medium batches of plastic products as well as prototyping molds is becoming of increasing demand by the tooling industry. these alloys are replacing the traditional use of steel in the cases above because they offer many advantages such as very high thermal conductivity associated with good corrosion and wear resistance presenting good machinability in milling and electrical discharge machining operations. unfortunately there is little technological knowledge on the electrical discharge machining (edm) of high-strength aluminium alloys, especially about the amp 8000 alloy. the duty factor, which means the ratio between pulse duration and pulse cycle time exerts an important role on the performance of edm. this work has carried out an experimental study on the variation of the duty factor in order to analyze its influence on material removal rate and volumetric relative wear under roughing conditions of edm process. the results showed that high values of duty factor are possible to be applied without bringing instability into the edm process and with improvement of material removal rate and volumetric relative wear.
Die-sinking electrical discharge machining of a high-strength copper-based alloy for injection molds
Amorim, F. L.;Weingaertner, W. L.;
Journal of the Brazilian Society of Mechanical Sciences and Engineering , 2004, DOI: 10.1590/S1678-58782004000200004
Abstract: high-strength copper alloys are used as materials for injection molding tools or as cores and inserts in steel molds because of their high thermal conductivity, corrosion and wear resistance. unfortunately, there is little technological knowledge on the electrical discharge machining (edm) of copper-beryllium astm c17200 alloy. in this work, rough and finish machining conditions were tested using copper and tungsten-copper as materials for the electrodes. cross-sectional micrographic and hardness examinations as well as surface roughness measurements were also carried out on workpieces after machining in order to study the thermally affected zones. appropriate parameters settings for edm of the investigated alloy are suggested.
Influence of duty factor on the die-sinking Electrical Discharge Machining of high-strength aluminum alloy under rough machining
Amorim F. L.,Weingaertner W. L.
Journal of the Brazilian Society of Mechanical Sciences , 2002,
Abstract: The use of high-strength aluminium alloys as material for injection molding tools to produce small and medium batches of plastic products as well as prototyping molds is becoming of increasing demand by the tooling industry. These alloys are replacing the traditional use of steel in the cases above because they offer many advantages such as very high thermal conductivity associated with good corrosion and wear resistance presenting good machinability in milling and electrical discharge machining operations. Unfortunately there is little technological knowledge on the Electrical Discharge Machining (EDM) of high-strength aluminium alloys, especially about the AMP 8000 alloy. The duty factor, which means the ratio between pulse duration and pulse cycle time exerts an important role on the performance of EDM. This work has carried out an experimental study on the variation of the duty factor in order to analyze its influence on material removal rate and volumetric relative wear under roughing conditions of EDM process. The results showed that high values of duty factor are possible to be applied without bringing instability into the EDM process and with improvement of material removal rate and volumetric relative wear.
The behavior of graphite and copper electrodes on the finish die-sinking electrical discharge machining (EDM) of AISI P20 tool steel
Amorim, Fred L.;Weingaertner, Walter L.;
Journal of the Brazilian Society of Mechanical Sciences and Engineering , 2007, DOI: 10.1590/S1678-58782007000400004
Abstract: the machining parameter settings installed at cnc edm machines are developed under optimum process conditions. standard workpiece and electrode materials are used traditionally by machine manufacturers to establish the edm parameter settings. however, this is not the usual situation of the tooling industry, where many different grades of workpiece and tool electrode materials are used. consequently, the customers are required to develop their own process parameters, which normally demand many experimental tests. according to the aforementioned argument an experimental investigation on the edm of aisi p20 tool steel under finish machining has been carried out. the tests were performed with graphite and copper as tool electrodes. important edm electrical parameters that influence the process performance were investigated. the measured technological outputs were the material removal rate vw, volumetric relative wear j and workpiece surface finish ra . the main conclusions can be summarized as follows: the best results for material removal rate vw were reached when edm with negative graphite electrodes. graphite and copper tools presented similar results of vw for positive polarity. for graphite and copper tools the lowest values of volumetric relative wear were achieved for positive polarity. the best surface roughness ra was obtained for copper electrodes under negative polarity.
Scenario Archetypes: Converging Rather than Diverging Themes
Dexter V. L. Hunt,D. Rachel Lombardi,Stuart Atkinson,Austin R. G. Barber,Matthew Barnes,Christopher T. Boyko,Julie Brown,John Bryson,David Butler,Silvio Caputo,Maria Caserio,Richard Coles,Rachel F. D. Cooper,Raziyeh Farmani,Mark Gaterell,James Hale,Chantal Hales,C. Nicholas Hewitt,Lubo Jankovic,I. Jefferson,J. Leach,A. Rob MacKenzie,Fayyaz Ali Memon,Jon P. Sadler,Carina Weingaertner,J. Duncan Whyatt,Christopher D. F. Rogers
Sustainability , 2012, DOI: 10.3390/su4040740
Abstract: Future scenarios provide challenging, plausible and relevant stories about how the future could unfold. Urban Futures (UF) research has identified a substantial set (>450) of seemingly disparate scenarios published over the period 1997–2011 and within this research, a sub-set of >160 scenarios has been identified (and categorized) based on their narratives according to the structure first proposed by the Global Scenario Group (GSG) in 1997; three world types (Business as Usual, Barbarization, and Great Transitions) and six scenarios, two for each world type (Policy Reform—PR, Market Forces—MF, Breakdown—B, Fortress World—FW, Eco-Communalism—EC and New Sustainability Paradigm—NSP). It is suggested that four of these scenario archetypes (MF, PR, NSP and FW) are sufficiently distinct to facilitate active stakeholder engagement in futures thinking. Moreover they are accompanied by a well-established, internally consistent set of narratives that provide a deeper understanding of the key fundamental drivers (e.g., STEEP—Social, Technological, Economic, Environmental and Political) that could bring about realistic world changes through a push or a pull effect. This is testament to the original concept of the GSG scenarios and their development and refinement over a 16 year period.
Determination of the relative position between grinding wheel and a cylindrical workpiece on a 7 axis grinding machine by acoustic emission
Weingaertner, Walter Lindolfo;Boaron, Adriano;
Journal of the Brazilian Society of Mechanical Sciences and Engineering , 2012, DOI: 10.1590/S1678-58782012000100004
Abstract: the contact between grinding wheel and workpiece in the grinding process is recognized by acoustic emission (ae). two acoustic emission monitoring systems (ms) were integrated into a 3 axis cnc grinding machine. a laptop allows the signal acquisition and visualization. the acquired aerms signals from the contact between tool and workpiece are analyzed permitting to establish the most suitable ae monitoring system to recognize the contact in a particular grinding machine. in a second experimental setup the selected ms was installed on a 7 axis tool grinding machine at an industrial partner. at this partner, the relative position between grinding wheel and workpiece was previously determined manually. this procedure has a direct influence on the results depending on the technical skills of the operator. the automation of this activity supported by acoustic emission has led to satisfactory results regarding the relative position between grinding wheel and workpiece and contributed to the setup time reduction.
Chronic Morphine Treatment Attenuates Cell Growth of Human BT474 Breast Cancer Cells by Rearrangement of the ErbB Signalling Network
Inka Regine Weingaertner, Sarah Koutnik, Hermann Ammer
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0053510
Abstract: Background There is increasing evidence that opioid analgesics may interfere with tumour growth. It is currently thought that these effects are mediated by transactivation of receptor tyrosine kinase (RTK)-controlled ERK1/2 and Akt signalling. The growth of many breast cancer cells is dependent on hyperactive ErbB receptor networks and one of the most successful approaches in antineoplastic therapy during the last decade was the development of ErbB-targeted therapies. However, the response rates of single therapies are often poor and resistance mechanisms evolve rapidly. To date there is no information about the ability of opioid analgesics to interfere with the growth of ErbB-driven cancers. Methods and Principal Findings Here we demonstrate that ErbB2 overexpressing BT474 human breast cancer cells carry fully functional endogenous μ-opioid receptors. Most interestingly, the acute opioid effects on basal and Heregulin-stimulated ERK1/2 and Akt phosphorylation changed considerably during chronic Morphine treatment. Investigation of the underlying mechanism by the use of protein kinase inhibitors and co-immunoprecipitation studies revealed that chronic Morphine treatment results in rearrangement of the ErbB signalling network leading to dissociation of ERK1/2 from Akt signalling and a switch from ErbB1/ErbB3 to ErbB1/ErbB2-dependent cell growth. In chronically Morphine-treated cells Heregulin-stimulated ERK1/2 signalling is redirected via a newly established PI3K- and metalloproteinase-dependent feedback loop. Together, these alterations result in apoptosis of BT474 cells. A similar switch in Heregulin-stimulated ERK1/2 signalling from an ErbB2-independent to an ErbB2-, PI3K- and metalloproteinase-dependent mechanism was also observed in κ-opioid receptor expressing SKBR3 human mammary adenocarcinoma cells. Conclusions and Significance The present data demonstrate that the ErbB receptor network of human breast cancer cells represents a target for chronic Morphine treatment. Rearrangement of ErbB signalling by chronic Morphine may provide a promising strategy to enhance the sensitivity of breast cancer cells to ErbB-directed therapies and to prevent the development of escape mechanisms.
Aspects on the optimization of die-sinking EDM of tungsten carbide-cobalt
Amorim, Fred Lacerda;Weingaertner, Walter Lindolfo;Bassani, Irionson Antonio;
Journal of the Brazilian Society of Mechanical Sciences and Engineering , 2010, DOI: 10.1590/S1678-58782010000500009
Abstract: at present, due to their properties, the tungsten carbide-cobalt (wc-co) composite materials are in huge demand by industry to manufacture special tools, dies/molds and components under erosion. the powder metallurgy is the usual process applied to obtain wc-co products, but in some cases this process is unable to produce tools of very complex shapes and highly intricate details. thus, additional conventional and non-conventional machining processes are required. in this context, the electrical discharge machining (edm) is an efficient alternative process. however, the edm parameters have to be properly set for any different tungsten carbide-cobalt composition and electrode material to achieve an appropriate level of machining performance. in this work, a special grade of tungsten carbide-cobalt was used as workpiece and a copper-tungsten alloy as electrode. experiments on important edm electrical and non-electrical parameter settings with reference to material removal rate, electrode wear ratio and surface roughness were carried out under typical rough and finish machining. this paper contributes with an attempt to provide insightful guidelines to optimize electrical discharge machining of wc-co composite materials using cuw alloy electrodes.
Cancer: Tumor Iron Metabolism, Mitochondrial Dysfunction and Tumor Immunosuppression; “A Tight Partnership—Was Warburg Correct?”  [PDF]
Robert L. Elliott, Jonathan F. Head
Journal of Cancer Therapy (JCT) , 2012, DOI: 10.4236/jct.2012.34039
Abstract: Over the last 30 years there have been numerous worldwide investigators involved in cancer research. Billions of dollars have been spent on drug development and cancer research; however, with all of the new agents and modalities of treatment, we have honestly not significantly improved the overall survival of the Stage IV cancer patient. There is and will not be a magic bullet treatment, thus the extensive title of this paper. We are convinced that unless we use multiple innovative therapies in combination with conventional treatment, we will never truly defeat this disease. We have attempted to address this problem by presenting in detail some of these complex mechanisms involved in tumorigenesis, progression, escape, and metastasis. Most investigators have their own special area of interest, but if we are to conquer this scourge, we must develop an extensive, multifaceted, comprehensive approach. Hopefully this article will contribute to awareness and further insight into this very serious and complicated problem, so we can improve quality of life and improve the survival of the Stage IV cancer patient.
A Case Report of Mesenteric Panniculitis and Primary Sjögren’s Syndrome  [PDF]
R. L. Batten, W. F. Ng
Open Journal of Rheumatology and Autoimmune Diseases (OJRA) , 2013, DOI: 10.4236/ojra.2013.34036
Abstract: Mesenteric Panniculitis is a benign fibro-inflammatory process involving adipose tissue of the mesentery. It is characterised by fat necrosis, chronic inflammation and fibrosis, causing thickening and shortening of the mesentery. Patients may present with localised abdominal pain, abdominal mass, intestinal obstruction and ischaemic colitis. We report a case of mesenteric panniculitis causing abdominal pain in a patient with active Primary Sjogren’s Syndrome. The rarity of this case makes it of interest. We review the current literature on mesenteric panniculitis and its association with connective tissue disease and inflammatory conditions. A 64-year-old Caucasian male presented in 1994 with dry mouth. A diagnosis of Primary Sjogren’s Syndrome (PSS) was made on salivary gland biopsy. In 2010 he presented with an exacerbation of his eye symptoms, muscle pain and fatigue. He complained of abdominal pain and night sweating, but denied any weight loss or change in bowel habit. There was no significant past medical history other than PSS. On examination he had a small right submandibular node and mild synovitis at the right proximal interphalangeal joint and carpometacarpal joint. Examination of the abdomen showed marked umbilical tenderness but no organomegally. Blood tests at this time showed an active inflammation: CRP of 61 (NR < 5 mg/L), ESR 39 (NR < 20 mm/s), strongly positive ENA Ro and La. IgG was elevated at 18.6 (NR 5.8-15.4), Complement was low at 0.17 (NR 0.18-0.6). An abdominal ultrasound scan demonstrated a 6 × 3 ×3 cmarea of diffuse homogenous fat encasing some mesenteric vessels in the area of focal tenderness. CT abdomen and pelvis showed oedematous mesenteric fat and lymph nodes in the jejunal small bowel mesentery, consistent with mesenteric panniculitis. Laparoscopic biopsy was discussed with the surgical team, but was felt not indicated as risk outweighed potential benefit. The patient was treated with a 9-week reducing course of oral steroids. His abdominal symptoms resolved although CT abdomen showed little improvement in mesenteric panniculitis. A review of the literature suggests that currently there is no standard treatment and management should be guided by
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