Tool-Wear-Estimation System in Milling Using Multi-View CNN Based on Reflected Infrared Images.

A novel method for tool wear estimation in milling using infrared (IR) laser vision and a deep-learning algorithm is proposed and demonstrated. The measurement device employs an IR line laser to irradiate the tool focal point at angles of -7.5°, 0.0°, and +7.5° to the vertical plane, and three cameras are placed at 45° intervals around the tool to collect the reflected IR light at different locations. For the processing materials and methods, a dry processing method was applied to a 100 mm × 100 mm × 40 mm SDK-11 workpiece through end milling and downward cutting using a TH308 insert. This device uses the diffused light reflected off the surface of a rotating tool roughened by flank wear, and a polarization filter is considered. As the measured tool wear images exhibit a low dynamic range of exposure, high dynamic range (HDR) images are obtained using an exposure fusion method. Finally, tool wear is estimated from the images using a multi-view convolutional neural network. As shown in the results of the estimated tool wear, a mean absolute error (MAE) of prediction error calculated was to be 9.5~35.21 µm. The proposed method can improve machining efficiency by reducing the downtime for tool wear measurement and by increasing tool life utilization.

Prediction of Drill Bit Breakage Using an Infrared Sensor.

In this paper, a novel drill bit breakage prediction method featuring a low-cost commercial infrared sensor to monitor drill bit corner wear is proposed. In the proposed method, the drill bit outer corner wear state can be monitored by measuring reflected infrared light because the reflection phenomenon is influenced by wear, edge shape, and surface roughness of the drill bit. In the experiments, a titanium workpiece was drilled without using cutting fluid to accelerate drill bit fracture. After drilling a hole in the workpiece, reflected infrared light was measured for the drill bit rotating at 100 rpm. Collected data on intensity of infrared light reflected from the circumferential surface of the drill bit versus the rotation angle of the drill bit were considered to predict tool breakage; two significant positions to predict tool breakage were found from the reflected infrared light graphs. By defining gradient vectors from the slopes of the reflected infrared light curves, a reliable criterion for determining drill bit breakage could be established. The proposed method offers possibilities for new measurement and analysis methods that have not been used in conventional tool wear and damage studies. The advantage of the proposed method is that the measurement device is easy to install and the measured signal is resistant to electromagnetic noise and ambient temperature because optical fiber is used as the signal transmission medium. It also eliminates the need for complex analysis of the measured signal, eliminating the need for a high-performance analyzer and reducing analysis time.

Development of aqueous mobile phase using chaotrope for the chromatographic determination of melamine in infant formula.

Direct analysis of melamine using reverse phase chromatography is a challenge because this compound's small size and strong polar nature leads to abnormal peak symmetry as well as poor retention. Here, we introduce a simple and reliable reverse phase liquid chromatographic method using sodium hexafluorophosphate to modify an acidic aqueous eluent, resulting in improved chromatographic behaviors of melamine in complex food matrices. Variables affecting the retention mechanism, including chaotrope type, concentration and stationary phase, were investigated. Under optimum conditions, melamine retention, separation efficiency, peak shape and reproducibility were significantly improved as compared to other methods that use ionic liquids or a micellar mobile phase. No interference affected melamine detection when infant formula was applied as the food matrix. Analytical reliability was demonstrated through estimation of validation parameters such as specificity, linearity, precision, accuracy and recovery. This method is suitable for routine analysis of melamine in infant formula. More noteworthy, this is the first time that an organic solvent-free mobile phase using chaotropic salt, meeting the concept of green chemistry, has been proposed.

Determination of urazamide in pharmaceutical preparation with room temperature ionic liquid.

A high performance liquid chromatographic method was developed and validated for the determination of urazamide in pharmaceutical preparation with novel green aqueous mobile phase modified with room temperature ionic liquids (RTILs). 1-Ethyl-3-methyl-imidazolium tetrafluoroborate ([EMIM][BF4]) was selected as a mobile phase additive to improve retention and avoid baseline disturbances at t0. Various mobile phase parameters such as cation moiety, chaotropic anion moiety, pH and concentration of RTILs were optimized to determine urazamide at the proper retention time. The assay was validated according to International Conference on Harmonization guidelines. The linearity of the calibration curve was good (r2 > 0.999). Intra-day precision varied between 0.50 and 1.23%. Relative standard deviations of inter-day precision ranged between 1.07 and 1.66%. Recoveries in tablets ranged between 99.7 and 101.2% and it was successfully applied to determine urazamide in pharmaceutical preparations.

The cytoprotective effect of Rumex Aquaticus Herba extract against hydrogen peroxide-induced oxidative stress in AGS cells.

The Rumex Aquaticus Herba extract containing quercetin-3-ß-D-glucuronopyranoside (ECQ) has been reported to exhibit various pharmacological activities, including anti-inflammatory and anti-oxidative effects. This plant has been traditionally used for the treatment of diarrhea, disinfestation, edema and jaundice, and as an antipyretic drug. The aim of the present study was to investigate the ability of ECQ to protect against oxidative damage and to determine its signaling mechanism in AGS cells. The protein expressions of heme oxygenase-1 (HO-1) and nuclear factor-erythroid 2 related factor 2 (Nrf2) were measured by Western blots. Cell viability was measured by MTT assay. Intracellular reactive oxygen species (ROS) levels were measured using 2',7'-dichlorofluorescein diacetate. Glutathione peroxidase levels were measured using kits. The protein expressions of HO-1 and its upstream mediator, Nrf2, increased after ECQ treatment. The HO-1 inhibitor, ZnPP, repressed the protective effect of ECQ on H2O2-induced cell damage. We found that LY294002, a specific PI3 K/Akt inhibitor, suppressed ECQ-induced HO-1 expression. ECQ significantly attenuated H2O2-induced cytotoxicity and ROS generation. Also, ECQ enhanced the antioxidant enzyme activities of glutathione peroxidase. These results suggest that ECQ exerts a cytoprotective effect against H2O2-induced oxidative stress by upregulation of Nrf2/HO-1 via the PI3 K/Akt pathway.