Varying CFRP workpiece temperature during slotting : effects on surface metrics, cutting forces and chip geometry

Carbon fibre reinforced thermoset polymer (CFRP) components are typically edge trimmed using a milling process to achieve final part shape. During this process the material is subject to significant heating at the tool-workpiece interface. Damage due to heating is fibre orientation specific; for some orientations it can lead to matrix smearing, potentially hiding defects and for others it can increase pullout. Understanding these relationships is critical to attaining higher throughput by edge milling. For the first time this study focuses on active heating of the CFRP rather than passive measurement, through use of a thermocouple controlled system to heat a CFRP workpiece material from room temperature (RT) up to 110 °C prior to machining. Differences in cutting mechanisms for fibres oriented at 0, 45, 90 and -45° are observed with scanning electron microscopy (SEM), and quantified with using focus variation with an increase of 89.9% Sa reported between RT and 110°C CFRP panel pre-heating. Relationships to cutting forces through dynamometer readings and tool temperature through infra-red (IR) measurements are also made with a novel optical method to measure cut chips presented. Results show an increase in chip length and width for increasing cutting temperature from RT to 110°C (3.39 and 0.79 µm for length and width, respectively). This work improves current understandings of how the cutting mechanism changes with increased temperature and suggests how improved milling throughput can be achieved

Epifluorescent microscopy of edge-trimmed carbon fibre-reinforced polymers : an alternative to computed tomography scanning

X-Ray computed tomography (XCT) can be used to detect edge-milled carbon fibre-reinforced polymer (CFRP) defects. Significantly this method is able to show subsurface defects that cannot be captured by traditional methods such as stylus-based or more novel areal methods of surface quality measurement. While useful, this method can be prohibitive due to high equipment cost, scanning time and image resolution. XCT can often produce artefacts which falsely predict damage or obscure damage and depending on machine X-ray power often cannot resolve damage to fibre diameter which is critical when observing milled quality of the surface/subsurface. This study utilises epifluorescent (EF) optical microscopy to provide high-quality optical images as an alternative to XCT to observe through-depth damage of CFRP materials. The method of computing the novel damage criteria is presented, as well as the validation of the method which compares EF to XCT. Subsurface damage of fabric and unidirectional (UD) materials in 0°, 45°, 90° and −45° orientations to the cutting edge is observed to demonstrate typical defects. A novel metric resulting from the EF method provides a total area of damage when compared to a theoretically straight cut across the face of the edge-milled CFRP. The method shows that different subsurface damage exists for different fibre orientations to the cutting edge, highlighting the clear need for through-depth analysis of machined edges. In addition, the method is shown to be a suitable alternative to XCT with scope for further development of industrial aerospace and automotive quality control of machined CFRP parts

Expected performance of the CDF plug upgrade calorimeter at TeV33

We have evaluated the performance of the CDF plug tile/fiber calorimeter under the radiation environment at a luminosity of 1 x 10{sup 33}cm{sup -2}s{sup -1} at TeV33. The issues covered are the radiation damage, the anode current of photomultipliers, and the energy miss-measurement due to the minimum bias event pile-ups. The plug calorimeter is expected to perform as precision calorimetry in the pseudorapidity range up to {approximately}2.3

Microbial Community Composition of Two Environmentally Conserved Estuaries in the Midorikawa River and Shirakawa River

To provide a general overview of the microbial communities in environmentally conserved estuaries, the top 5 cm of sediment was sampled from the sandy estuary of the Shirakawa River and from the muddy estuary of the Midorikawa River. Higher amounts of organic matter were detected in the Midorikawa estuary sample than in the Shirakawa estuary sample. Measurement of redox potential revealed that the Shirakawa estuary was aerobic and the Midorikawa estuary was much less aerobic. Clone analysis was performed by targeting partial 16S rRNA gene sequences and using extracted DNA from the samples as a template. Various bacteria were detected, among which Gammaproteobacteria was dominant at both estuaries. Unclassified clones were detected in the Gammaproteobacteria group, mainly among samples from the Midorikawa estuary. Other detected bacterial groups were Alphaproteobacteria, Deltaproteobacteria, Chloroflexi, Actinobacteria, and Bacteroidetes. All the Deltaproteobacteria clones were anaerobic sulfate-reducing bacteria. Those aerobic and anaerobic bacteria coexisted in the top 5 cm of the estuary sediments indicating the surface layer have active sulfur and carbon cycle. Abundance of aerobic Gammaproteobacteria may be an indicator for conserved estuaries

Effects of tool coating and tool wear on the surface quality and flexural strength of slotted CFRP

Machining of carbon fibre reinforced polymer (CFRP) is abrasive and causes significant tool wear. The effect of tool wear on static flexural strength is investigated, using edge trimming with uncoated carbide and chemical vapour deposition (CVD) diamond coated burr style tools. Edge rounding (ER) criteria along with flank wear are used to observe tool degradation with ER shown to preferentially wear allowing the tool to become cyclically sharper and duller, corresponding to fluctuating dynamometer readings, a novelty for CFRP machining. Areal surface metrics degraded for an uncoated tool due to changes in cutting mechanism, whilst for up to 16.2 m of linear traverse, the coated tool showed limited changes. Tool wear, caused by edge trimming 7.2 m of CFRP, using an uncoated carbide tool, provided a flexural strength reduction of up to 10.5 %, directly linking tool wear to reduced mechanical strength

Synthesis and biological activity of α-galactosyl ceramide KRN7000 and galactosyl (α1→2) galactosyl ceramide

We herein report a faster and less cumbersome synthesis of the biologically attractive, α-galactosyl ceramide (α-GalCer), known as KRN7000, and its analogues. More importantly, the use of a silicon tethered intramolecular glycosylation reaction gave easy access to the diglycosyl ceramide Gal(α1→2)GalCer, which has been shown to require uptake and processing to the biologically active α-GalCer derivative

Effects of machine stiffness and cutting tool design on the surface quality and flexural strength of edge trimmed carbon fibre reinforced polymers

A 22 full factorial design of experiment is used to investigate the effects of two machining platforms (5-axis elevated gantry versus 6-axis articulated robotic system) and two cutting tool designs (burr versus herringbone) on surface metrics and flexural strength of a 14 ply T300 2x2 carbon fibre reinforced polymer. A range of areal metrics were considered to characterise the surface with Sal and Stdi best able to represent differences due to the choice of robotic system or overhead gantry. The robotic system produces coupons with flexural strengths up to 26% higher than the overhead gantry. The choice of tool has a less significant effect however machine-tool interactions do play a role in the flexural strength. Analysis using scanning electron microscopy shows that defects may be obscured by smeared matrix which may contribute to overall flexural strength differences

Indoleamine 2,3-dioxygenase is a novel prognostic indicator for endometrial cancer

Indoleamine 2,3-dioxygenase (IDO) is a tryptophan-catabolising enzyme inducing immune tolerance. The present study aimed to investigate IDO expression and its prognostic significance in endometrial cancer. Indoleamine 2,3-dioxygenase expression in endometrial cancer tissues (n=80) was immunohistochemically scored as four groups (IDO−, 1+, 2+, and 3+). The high IDO expression (IDO2+ or 3+) in tumour cells was found in 37 (46.3%) of the 80 cases, and was positively correlated with surgical stage, myometrial invasion, lymph-vascular space involvement, and lymph node metastasis, but not with the histological grade. Patients with high IDO expression had significantly impaired overall survival and progression-free survival (PFS) (P=0.002 and P=0.001, respectively) compared to patients with no or weak expression of IDO (IDO− or 1+). The 5-year PFS for IDO−/1+, 2+, and 3+ were 97.7, 72.9, and 36.4%, respectively. Even in patients with early-stage disease (International Federation of Gynecology and Obstetrics I/II, n=64), the PFS for IDO2+/3+ was significantly poor (P=0.001) compared to that for IDO−/1+. On multivariate analysis, IDO expression was an independent prognostic factor for PFS (P=0.020). These results indicated that the high IDO expression was involved in the progression of endometrial cancer and correlated with the impaired clinical outcome, suggesting that IDO is a novel and reliable prognostic indicator for endometrial cancer

Measurement of the Helicity Fractions of W Bosons from Top Quark Decays Using Fully Reconstructed top-antitop Events with CDF II

We present a measurement of the fractions F_0 and F_+ of longitudinally polarized and right-handed W bosons in top quark decays using data collected with the CDF II detector. The data set used in the analysis corresponds to an integrated luminosity of approximately 318 pb -1. We select ttbar candidate events with one lepton, at least four jets, and missing transverse energy. Our helicity measurement uses the decay angle theta*, which is defined as the angle between the momentum of the charged lepton in the W boson rest frame and the W momentum in the top quark rest frame. The cos(theta*) distribution in the data is determined by full kinematic reconstruction of the ttbar candidates. We find F_0 = 0.85 +0.15 -0.22 (stat) +- 0.06 (syst) and F_+ = 0.05 +0.11 -0.05 (stat) +- 0.03 (syst), which is consistent with the standard model prediction. We set an upper limit on the fraction of right-handed W bosons of F_+ < 0.26 at the 95% confidence level.Comment: 11 pages, 2 figures, submitted to Phys. Rev.

Top quark mass measurement using the template method at CDF

We present a measurement of the top quark mass in the lepton+jets and dilepton channels of $t\bar{t}$ decays using the template method. The data sample corresponds to an integrated luminosity of 5.6 fb$^{-1}$ of $p\bar{p}$ collisions at Tevatron with $\sqrt{s}=1.96$ TeV, collected with the CDF II detector. The measurement is performed by constructing templates of three kinematic variables in the lepton+jets and two kinematic variables in the dilepton channel. The variables are two reconstructed top quark masses from different jets-to-quarks combinations and the invariant mass of two jets from the $W$ decay in the lepton+jets channel, and a reconstructed top quark mass and $m_{T2}$, a variable related to the transverse mass in events with two missing particles, in the dilepton channel. The simultaneous fit of the templates from signal and background events in the lepton+jets and dilepton channels to the data yields a measured top quark mass of $M_{top} = 172.1 \pm 1.1(stat) \pm 0.9(syst).$Comment: submitted to Phys. Rev.