458 research outputs found
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On the Interface Between LENS® Deposited Stainless Steel 304L Repair Geometry and Cast or Machined Components
Laser Engineered Net Shaping™ (LENS®) is being evaluated for use as a metal component
repair/modification process. A component of the evaluation is to better understand the characteristics of
the interface between LENS deposited material and the substrate on which it is deposited. A processing
and metallurgical evaluation was made on LENS processed material fabricated for component
qualification tests. A process parameter evaluation was used to determine optimum build parameters
and these parameters were used in the fabrication of tensile test specimens to study the characteristics of
the interface between LENS deposited material and several types of substrates. Analyses of the
interface included mechanical properties, microstructure, and metallurgical integrity. Test samples
were determined for a variety of geometric configurations associated with interfaces between LENS
deposited material and both wrought base material or previously deposited LENS material. Thirteen
different interface configurations were fabricated for evaluation representing a spectrum of deposition
conditions from complete part build, to hybrid substrate-LENS builds, to repair builds for damaged or
re-designed housings. Good mechanical properties and full density were observed for all configurations.
When tested to failure, fracture occurred by ductile microvoid coalescence. The repair and hybrid
interfaces showed the same metallurgical integrity as, and had properties similar to, monolithic LENS
deposits.Mechanical Engineerin
Privacy and ethical challenges of the Amelogenin sex test in forensic paternity/kinship analysis: Insights from a 13-year case history
The Amelogenin sex test included in forensic DNA typing kits has the potential to identify congenital conditions such as differences/disorders of sex development (DSD). It can also reveal mismatches between genotypic sex and gender marker in identity documents of transgender persons who obtained legal gender recognition.
In a 13-year case history of paternity/kinship tests, involving n = 962 females and n = 1001 males, two
mismatches between Amelogenin sex test (male) and gender marker (female), and three cases of chromosomal DSD (Klinefelter syndrome) were observed.
The concrete risk of observing Amelogenin anomalies, their potential causes, and the context in which they
occur (forensic, i.e. non-medical) mean that laboratory operators are called to strike a complex balance between privacy interests and individual health rights when providing preliminary information and reporting Amelogenin incidental findings. This case history argues for the need of a more responsible approach towards the Amelogenin sex test in the forensic community
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Thermal Behavior in the Lens Process
Direct laser metal deposition processing is a promising manufacturing technology which
could significantly impact the length oftime between initial concept and finished part. For
adoption ofthis technology in the manufacturing environment, further understanding is required
to ensure robust components with appropriate properties are routinelyfabricated. This requires a
complete understanding ofthe thermal history.during part fabrication and control ofthis behavior.
This paper will describe our research to understand the thermal behavior for the Laser Engineered
Net Shaping (LENS) process!, where a component is fabricated by focusing a laser beam onto a
substrate to create a molten pool in which powder particles are simultaneously injected to build
each layer. The substrate is moved beneath the l~ser beam to deposit a thin cross section, thereby
creating the desired geometry for each layer. After deposition of each layer, the powder delivery
nozzle and focusing lens assembly is incremented in the positive Z-direction, thereby building a
three dimensional component layer additively.
It is important to control the thermal behavior to reproducibly fabricate parts. The
ultimate intent is to monitor the thermal signatures and to incorporate sensors and feedback
algorithms to control part fabrication. With appropriate control, the geometric properties
(accuracy, surface finish, low warpage) as well as the materials' properties (e.g. strength,
ductility) of a component can be dialed into the part through the fabrication parameters. Thermal
monitoring techniques will be described, and their particular benefits highlighted. Preliminary
details in correlating thermal behavior with processing results will be discussed.Mechanical Engineerin
Detecting expert’s eye using a multiple-kernel Relevance Vector Machine
Decoding mental states from the pattern of neural activity or overt behavior is an intensely pursued goal. Here we applied machine learning to detect expertise from the oculomotor behavior of novice and expert billiard players during free viewing of a filmed billiard match with no specific task, and in a dynamic trajectory prediction task involving ad-hoc, occluded billiard shots. We have adopted a ground framework for feature space fusion and a Bayesian sparse classifier, namely, a Relevance Vector Machine. By testing different combinations of simple oculomotor features (gaze shifts amplitude and direction, and fixation duration), we could classify on an individual basis which group - novice or expert - the observers belonged to with an accuracy of 82% and 87%, respectively for the match and the shots. These results provide evidence that, at least in the particular domain of billiard sport, a signature of
expertise is hidden in very basic aspects of oculomotor behavior, and that expertise can be detected at the individual level both with ad-hoc testing conditions and under naturalistic conditions - and suitable data mining. Our procedure paves the way for the development of a test for the \u201cexpert\u2019s eye\u201d, and promotes the use of eye movements as an additional signal source in Brain-Computer-Interface (BCI) systems
LTF and DEFB1 polymorphisms are associated with susceptibility toward chronic periodontitis development
Objectives: Chronic periodontitis is a common pathological condition that affects the supporting tissue of the teeth, leading to progressive alveolar bone destruction and teeth loss. The disease is caused by bacteria and derives from an altered host immune and inflammatory response, also involving different factors such as the oral hygiene, smoking, and genetic background. The innate immune response, the first line of host defense, could also play an important role in the susceptibility to chronic periodontitis. In this study, we evaluated the possible association between periodontal disease and seven genetic variations within DEFB1 and LTF genes, encoding for \u3b2-defensins 1 and lactoferrin (two members of oral innate immune system), in an Italian isolated population.
Subjects and Methods: DEFB1 5\u2032UTR g. -52G>A (rs1799946), g. -44C>G (rs1800972), g. -20G>A (rs11362), 3\u2032UTR c*5G>A (rs1047031), c*87A>G (rs1800971), LTF p.Ala29Thr (rs1126477), and p.Lys47Arg (rs1126478) single nucleotide polymor- phisms (SNPs) were analyzed in 155 healthy individuals and 439 chronic periodontitis patients from North-East Italy.
Results: Significant associations were found between periodontitis and g. -20G>A (rs11362) and g. -44C>G (rs1800972) SNPs in DEFB1 gene as well as p.Ala29Thr (rs1126477) and p.Lys47Arg (rs1126478) SNPs in LTF gene.
Discussion: Our results suggest the involvement of DEFB1 and LTF genetic variations in the susceptibility toward development of periodontitis
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