2,222 research outputs found
Quantification of the In fluence of anisotropic plastic yielding on cold rolling force
Anisotropic mechanical properties in sheet material are of high importance, in particular for material to be used in stamping or deep drawing applications. The cold rolling process has a marked influence on the degree of anisotropy in the final product. However, the influence of material anisotropy on the cold rolling process itself has so far not been rigorously investigated. In this work, the degree of normal anisotropy is determined for two low-carbon steel grades after various degree of cold rolling reduction, both by X-ray diffraction as well as by tensile testing. The experimental work shows that material with high cold rolling reduction has non-negligible anisotropic properties; as a consequence the rolling force is seriously overestimated by cold rolling models with an isotropic yield criterion. It is therefore proposed to use the Hill48 yield criterion (instead of the von Mises criterion) in cold rolling models, this criterion takes anisotropic material behaviour into account. A comparison of cold rolling experiments with model predictions confirms that including the Hill48 yield criterion significantly improves the accuracy of a cold rolling model.</p
Monitoramento da multidisciplinaridade no processo de transferência de tecnologia em uma universidade: proposta de análise de cluster
ABSTRACTThis paper discusses the management of the technology transfer process conducted by a Technology Transfer Office (TTO) of a federal public university. Patent co-authorship and multidisciplinarity were used as concepts to evaluate and monitor the quality of academic and practical contribution and their potential for commercial application, using descriptive statistics and cluster analysis. Considering only multidisciplinary patents, binary cluster analysis was conducted, using Jaccard similarity measurement and single linkage method to determine proximity among academic units. Apart from the analysis of the number of patents, the approach enabled discussions and questions regarding the differences between patent generation patterns, resultant from the specific organizational culture and structures. The discussions are relevant to improve the identification of opportunities in technology transfer processes by the TTO
Sclerosing Mesenteritis
Background: A 55-year-old Caucasian man presented with weight loss, cramping abdominal pains, an increasing abdominal circumference and diarrhea. Physical examination showed no abnormalities besides a puffy abdomen. His past medical history included a recent subcutaneous swelling in the neck, histologically compatible to a benign solitary fibrous tumor. All blood results were within normal limits. Abdominal ultrasonography showed a tumor with diameter of 6.7 cm, probably originating from the pancreas, with ascites and retroperitoneal lymphadenopathy. This was followed by a CT scan. CT scan of the abdomen was repeated following therapy
Characterization of a new mutation (R292G) and a deletion at the human uroporphyrinogen decarboxylase locus in two patients with hepatoerythropoietic porphyria
A deficiency in the activity of uroporphyrinogen decarboxylase (UROD), the fifth enzyme of the haem biosynthetic pathway, is found in familial porphyria cutanea tarda (F-PCT) and hepatoerythropoietic porphyria (HEP). A new mutation (R292G) and a deletion have been found in a pedigree with two HEP patients (two sisters). The R292G mutation was not detected in 13 unrelated affected patients with F-PCT, so it appears to be uncommon. The possibility that the arginine 292 may participate at the active site of the enzyme is discussed. A summary of the 7 mutations/deletions found in the UROD gene with their frequency is presented
Northeastern Atlantic cold-water coral reefs and climate
U-series age patterns obtained on reef framework-forming cold-water corals collected over a nearly 6,000 km long continental margin sector, extending from off Mauritania to the south-western Barents Sea reveal strong climate influences on the geographical distribution and sustained development of these ecosystems. During glacial times densely populated cold-water coral reefs flourished in the temperate east Atlantic, where at present only scarce live coral occurrences exist. In contrast, climate warming induces a rapid northward colonization of cold-water coral reefs with the biogeographic limit advancing from ~45°N to ~70°N. Thus, we invoke here that north-south oscillations of the polar front during the past glacial-interglacial cycles and the consequent displacement of cold nutrient-rich intermediate waters and productivity drives the decline and expansion of cold-water coral ecosystems and its biogeographic limits in the northeast Atlantic
Geometry dependence of TLS noise and loss in a-SiC:H parallel plate capacitors for superconducting microwave resonators
Parallel plate capacitors (PPC) significantly reduce the size of
superconducting microwave resonators, reducing the pixel pitch for arrays of
single photon energy-resolving kinetic inductance detectors (KIDs). The
frequency noise of KIDs is typically limited by tunneling Two-Level Systems
(TLS), which originate from lattice defects in the dielectric materials
required for PPCs. How the frequency noise level depends on the PPC's
dimensions has not been experimentally addressed. We measure the frequency
noise of 56 resonators with a-SiC:H PPCs, which cover a factor 44 in PPC area
and a factor 4 in dielectric thickness. To support the noise analysis, we
measure the TLS-induced, power-dependent, intrinsic loss and
temperature-dependent resonance frequency shift of the resonators. From the TLS
models, we expect a geometry-independent microwave loss and resonance frequency
shift, set by the TLS properties of the dielectric. However, we observe a
thickness-dependent microwave loss and resonance frequency shift, explained by
surface layers that limit the performance of PPC-based resonators. For a
uniform dielectric, the frequency noise level should scale directly inversely
with the PPC area and thickness. We observe that an increase in PPC size
reduces the frequency noise, but the exact scaling is, in some cases, weaker
than expected. Finally, we derive an engineering guideline for the design of
KIDs based on PPC-based resonators.Comment: 13 pages, 11 figure
Interaction between geriatric syndromes in predicting three months mortality risk
Objectives: Capturing frailty using a quick tool has proven to be challenging. We hypothesise that this is due to the complex interactions between frailty domains. We aimed to identify these interactions and assess whether adding interactions between domains improves mortality predictability. Methods: In this retrospective cohort study, we selected all patients aged 70 or older who were admitted to one Dutch hospital between April 2015 and April 2016. Patient characteristics, frailty screening (using VMS (Safety Management System), a screening tool used in Dutch hospital care), length of stay, and mortality within three months were retrospectively collected from electronic medical records. To identify predictive interactions between the frailty domains, we constructed a classification tree with mortality as the outcome using five variables: the four VMS-domains (delirium risk, fall risk, malnutrition, physical impairment) and their sum. To determine if any domain interactions were predictive for three-month mortality, we performed a multivariable logistic regression analysis. Results: We included 4,478 patients. (median age: 79 years; maximum age: 101 years; 44.8% male) The highest risk for three-month mortality included patients that were physically impaired and malnourished (23% (95%-CI 19.0–27.4%)). Subgroups had comparable three-month mortality risks based on different domains: malnutrition without physical impairment (15.2% (96%-CI 12.4–18.6%)) and physical impairment and delirium risk without malnutrition (16.3% (95%-CI 13.7–19.2%)). Discussion: We showed that taking interactions between domains into account improves the predictability of three-month mortality risk. Therefore, when screening for frailty, simply adding up domains with a cut-off score results in loss of valuable information
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