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Low-frequency vibration cutting technology can actively generate an intermittent cutting process in which chips are broken up by vibrating the tool in the feed direction synchronized with the spindle rotation. The sinusoidal oscillation superimposed to feed drive motion triggers cutting thickness fluctuations so that air cutting occurs. To attain efficient and practical machining, selection of appropriate conditions for low-frequency vibration cutting is important. From a practical point of view, it is necessary to analyze the cutting process for its effects on tool wear as well as chip breakup. Low-frequency vibration cutting has been reported to reduce average cutting force and average cutting temperature. On the other hand, few studies have analyzed the effect of tool trajectory on the tool life, and thus the mechanism has not been fully clarified. In this study, the effects of low-frequency vibration on the tool life in turning operations were experimentally investigated for carbon steel, stainless steel, and titanium alloys. In low-frequency vibration cutting of ductile materials such as carbon steel and stainless steel, tool damage was significantly improved by designing an intermittent cutting process with large amplitude. On the other hand, the tool life for titanium alloys was deteriorated in low-frequency-vibration cutting. The experimental results indicated that the higher the vibration speed, the faster the tool wear progression in titanium alloy machining. Model-based analysis of the cutting force revealed a characteristic mechanism of the flank wear development that depends on the tool trajectory with low frequency vibration.

A graph $G$ is called edge-magic if there exists a bijective function $f:V\left(G\right) \cup E\left(G\right)\rightarrow \left\{1, 2, \ldots , \left\vert V\left( G\right) \right\vert +\left\vert E\left(G\right) \right\vert \right\}$ such that $f\left(u\right) + f\left(v\right) + f\left(uv\right)$ is a constant for each $uv\in E\left( G\right) $. Also, $G$ is called super edge-magic if $f\left(V \left(G\right)\right) =\left\{1, 2, \ldots , \left\vert V\left( G\right) \right\vert \right\}$. Furthermore, the super edge-magic deficiency $ \mu_{s}\left(G\right)$ of a graph $G$ is defined to be either the smallest nonnegative integer $n$ with the property that $G \cup nK_{1}$ is super edge-magic or $+ \infty$ if there exists no such integer $n$. In this paper, we introduce the parameter $l\left(n\right)$ as the minimum size of a graph $G$ of order $n$ for which all graphs of order $n$ and size at least $l\left(n\right)$ have $\mu_{s} \left( G \right)=+\infty $, and provide lower and upper bounds for $l\left(n\right)$. Imran, Baig, and Fe\u{n}ov\u{c}\'{i}kov\'{a} established that for integers $n$ with $n\equiv 0\pmod{4}$, $ \mu_{s}\left(D_{n}\right) \leq 3n/2-1$, where $D_{n}$ is the cartesian product of the cycle $C_{n}$ of order $n$ and the complete graph $K_{2}$ of order $2$. We improve this bound by showing that $ \mu_{s}\left(D_{n}\right) \leq n+1$ when $n \geq 4$ is even. Enomoto, Llad\'{o}, Nakamigawa, and Ringel posed the conjecture that every nontrivial tree is super edge-magic. We propose a new approach to attack this conjecture. This approach may also help to resolve another labeling conjecture on trees by Graham and Sloane.

This paper proposes a combined plastic and creep constitutive model of A533B1 pressure vessel steel to simulate progressive deformation of nuclear pressure vessels under severe accident conditions. To develop the model, recent tensile test data covering a wide range of temperatures (from RT to 1,100 °C) and strain rates (from 0.001%/s to 1.0%/s) was used. Comparison with experimental data confirms that the proposed combined plastic and creep model can well reflect effects of temperature and strain rate on tensile behaviour up to failure. In the companion paper (Part II), the proposed model will be used to simulate OECD lower head failure (OLHF) test data.

This paper proposes strain-based failure model of A533B1 pressure vessel steel to simulate failure, followed by application to OECD lower head failure (OLHF) test simulation for experimental validation. The proposed strain-based failure model uses simple constant and linear functions based on physical failure modes with the critical strain value determined either using the lower bound of true fracture strain or using the average value of total elongation depending on the temperature. Application to OECD Lower Head Failure (OLHF) tests shows that progressive deformation, failure time and failure location can be well predicted.

Ptychographic coherent diffraction imaging (PCDI) is a synchrotron X-ray microscopy technique that provides high spatial resolution and a wide field of view. To improve the performance of PCDI, the performance of the synchrotron radiation source and imaging detector should be improved. In this study, ptychographic diffraction pattern measurements using the CITIUS high-speed X-ray image detector and the corresponding image reconstruction are reported. X-rays with an energy of 6.5 keV were focused by total reflection focusing mirrors, and a flux of ∼2.6 × 1010 photons s−1 was obtained at the sample plane. Diffraction intensity data were collected at up to ∼250 Mcounts s−1 pixel−1 without saturation of the detector. Measurements of tantalum test charts and silica particles and the reconstruction of phase images were performed. A resolution of ∼10 nm and a phase sensitivity of ∼0.01 rad were obtained. The CITIUS detector can be applied to the PCDI observation of various samples using low-emittance synchrotron radiation sources and to the stability evaluation of light sources.

Buckling is a critical failure mode of the Fast Reactor Main Vessel (FRMV) subjected to seismic load. Post-buckling stability of FRMV is a crucial safety issue during excessive earthquakes. Our prior study revealed that global response becomes stable after buckling by phase-inverse mechanism. However, local fatigue cracks can initiate, penetrate and propagate under cyclic load. In the present study, shaking table experiments using cylindrical models are carried out. The post-buckling crack propagation process is experimentally observed and its mechanism is analyzed. It is shown that dominant cracks always propagate in circumference direction along the diagonal of the diamond-shape buckling dimple. Rapid collapse due to unstable crack propagation never occurs. Instead, a stable propagation mode is observed, where crack growth rate declines with crack circumferential angle. This stability is owing to the displacement-controlled characteristic of dynamic load, which results from the increasing frequency ratio due to crack propagation. Furthermore, a simplified evaluation method based on the estimation of J-integral under displacement-controlled condition is applied to predict the crack growth rate. The comparison with experimental data shows a satisfactory agreement. As a complementary study on global stability of FRMV, the present study confirms a local stability mechanism after buckling, contributing to a more comprehensive understanding on the post-buckling behavior of FRMV.

Two well-known measurement methods use coherent x rays: x-ray photon correlation spectroscopy (XPCS) and coherent x-ray diffraction imaging (CXDI). We propose and demonstrate an approach to analyze particle motion in heterogeneous solutions over a wide spatiotemporal scale by combining XPCS and dynamic CXDI using a data-driven approach. By applying this approach to analyze of the dynamics of colloidal gold particles dispersed in aqueous polyvinyl alcohol solutions, we found that Brownian motion exists in the range of a few hundred nanometers, and two modes of motion exist in the micrometer range, i.e., trapping in a narrow region and diffusion motion along a preferred direction. This approach can be applied to analyze dynamic heterogeneity in materials and cells that do not transmit visible light and electrons.

As the first experiment at BL10U in NanoTerasu, tender X-ray ptychographic coherent diffraction imaging (PCDI) was conducted using a photon energy of 3.5 keV. The ptychographic diffraction patterns from a 200 nm thick Ta test chart and a micrometer-sized particle of sulfurized polymer were collected. Subsequently, phase images were reconstructed with resolutions of sub-20 nm and sub-50 nm, respectively. In the near future, tender X-ray PCDI with sub-10 nm resolution is anticipated to potentially revolutionize the visualization of nanoscale structures and chemical states in various functional materials composed of light elements.

Grade 91 steel is widely used in the boilers and piping of thermal power plants. There has been significant research interest in understanding the variations in creep characteristics among different heats of this steel for effective plant management. In recent years, thermal power plants have been subjected to frequent load changes and startup/shutdown to adjust power supply and demand and stabilize frequencies. These operational shifts have raised concerns regarding the potential for creep-fatigue damage in high-temperature components. Therefore, this research focuses on creep-fatigue properties of Grade 91 steel and their predictability. Tensile, creep, strain-controlled fatigue, and strain-controlled creep-fatigue tests were performed on six Grade 91 steels with different heats and/or histories, and the characteristics in each test were compared. As a result, the variations in creep-fatigue life among the materials were found to be correlated with the difference in creep characteristics and stress level during stress relaxation. Furthermore, the study involved a comparative assessment of the predictive performance of creep-fatigue life using five different approaches: time fraction, classical ductility exhaustion, modified ductility exhaustion, energy-based, and hybrid approaches. Among these approaches, the hybrid approach, based on inelastic strain energy density at fracture formulated as a function of inelastic strain rate, exhibited the most accurate predictive performance.

Two finite sequences s1 and s2 of nonnegative integers are called bigraphical if there exists a bipartite graph G with partite sets V1 and V2 such that s1 and s2 are the degrees in G of the vertices in V1 and V2, respectively. In this paper, we introduce the concept of 1-graphical sequences and present a necessary and sufficient condition for a sequence to be 1-graphical in terms of bigraphical sequences.

Abstract The effect of top blowing and bottom blowing conditions on spitting behavior was investigated by water model experiments and numerical calculation. The results of the water model experiment showed that reducing the jet velocity by using a larger nozzle diameter was effective for reducing spitting. The numerical calculation indicated that interference between the top blown gas jet and the bottom blowing plume increases the gas velocity at the rim of the cavity, causing heavier spitting. A new index using the geometrical locations of the neighboring cavity and plume was proposed. The spitting rate decreased under conditions with lower interference by avoiding interaction between the top blown gas jet and the bottom blowing plume. The energy distribution in the blowing process was discussed based on a water model experiment using bath mixing time, bath vibration, and the spitting rate. The energy for spitting was explained convincingly by the difference between the energy input and the energy of bath vibration, cavity formation, and bath mixing. The results implied lower interference of the top and bottom gas resulted in lower energy for spitting generation.

Built-up layer (BUL) formed on the tool rake face during cutting has the tool protective effect. As BUL can change the shape of tool resulting in variation of rake angle and edge radius, it may have significant influences on the cutting phenomena such as tool wear, cutting forces, and surface integrity. SUS304 stainless steel is very difficult to cut, leading to the rapid tool wear and poor surface quality. It also has a high tendency to form BUL during cutting due to its high work hardening rate and high chemical affinity. To actively and purposefully utilize BUL, the effects of the size of BUL on the wear of uncoated cemented carbide tools in dry cutting of SUS304 were investigated using the experimental and analytical methods in this study. The model for cutting processes included the effect of the size of BUL/BUE was presented. The cutting parameters were chosen to induce the stable BUL formation. After cutting, the worn cutting tools were analyzed using the laser confocal microscopy and scanning electron microscopy. It was confirmed that BUL can reduce the tool flank wear rate in the steady-state wear when its height is equal to or less than the uncut chip thickness. The results also showed that BUL formed at cutting speed 40 m/min not only can reduce the tool flank wear rate but also has few influences on the amplitude variation of cutting forces and surface roughness. Meanwhile, using the obtained experimental results and proposed model, simulation was conducted to evaluate the effects of the size of BUL on the tool flank wear formation. It was confirmed that BUL, especially when its height is close to the uncut chip thickness, which reduces the real rake angle to negative, can reduce the normal stress on the tool flank face and lead to a decrease in the tool flank wear rate.

Abstract Background Remifentanil decreases blood loss during spinal surgery, rhinoplasty, and endoscopic sinus surgery. However, there are no reports regarding its effect on intraoperative blood loss during endoscopic body surface surgery. The present study aimed to investigate the effect of intraoperative remifentanil on blood loss during endoscopic subcutaneous mastectomy. Methods In this single-center, retrospective observational study conducted from August 2005 to June 2010, 443 patients who underwent either endoscopic subcutaneous partial mastectomy or quadrantectomy were included (n = 231 and 212, respectively). Patients were categorized into the remifentanil and non-remifentanil groups (n = 154 and 289, respectively) based on intraoperative use of remifentanil. We compared the amount of blood loss between the remifentanil and non-remifentanil groups. Results Blood loss was significantly smaller in the remifentanil group than in the non-remifentanil group in patients undergoing partial mastectomy (median [25%, 75%], 60 [30, 94] vs. 90 [50, 165] ml, P

Built-up Layer (BUL), produced by accumulating workpiece on the tool rake face, has the tool protective effect and the smaller depth of overcutting during cutting of metal material. The main objective of this paper is to clarify the influences of coating characteristics on the BUL formation process during cutting of titanium alloy. Dry cuttings of Ti-6Al-4V with three different cutting tools (uncoated, PVD coated, and CVD coated carbide tools) were conducted. After the cutting tests, the cutting tools were observed through laser confocal microscopes (LCM) and scanning electron microscopy (SEM). The BUL formation conditions were examined from the viewpoint of the adhesion’s shape, surface roughness, and the amplitude variation of cutting force. From the results, as expected, it was confirmed that BUL can form on the tool rake face for different tools at the cutting speed below 50~70 m/min and it can protect the tool rake face from wear to some extent. It was also determined that the coating characteristic nearly has few effects on the BUL formation mechanism but it can change the size of BUL and affect the stability of BUL. On the other hand, the BUL formation played a great role on the fall-off of coating. Finally, the ability of BUL to decrease the tool wear was also analyzed. The results indicated that BUL can be used to decrease the tool wear formation and to extend the tool life at the cutting speed below 70 m/min during dry cutting of Ti-6Al-4V and the size of BUL plays a decisive role in the protective effect.

To investigate the contribution of body vibrations to the vibratory sensation induced by high-level, complex low-frequency noise, we conducted two experiments. In Experiment 1, eight male subjects were exposed to seven types of low-frequency noise stimuli: two pure tones [a 31.5-Hz, 100-dB(SPL) tone and a 50-Hz, 100-dB(SPL) tone] and five complex noises composed of the pure tones. For the complex noise stimuli, the sound pressure level of one tonal component was 100 dB(SPL) and that of another one was either 90, 95, or 100 dB(SPL). Vibration induced on the body surface was measured at five locations, and the correlation with the subjective rating of the vibratory sensation at each site of measurement was examined. In Experiment 2, the correlation between the body surface vibration and the vibratory sensation was similarly examined using seven types of noise stimuli composed of a 25-Hz tone and a 50-Hz tone. In both the experiments, we found that at the chest and the abdomen, the rating of the vibratory sensation was in close correlation with the vibration acceleration level (VAL) of the body surface vibration measured at each corresponding location. This was consistent with our previous results and suggested that at the trunk of the body (the chest and the abdomen), the mechanoreception of body vibrations plays an important role in the experience of the vibratory sensation in persons exposed to high-level low-frequency noise. At the head, however, no close correlation was found between the rating of the vibratory sensation and the VAL of body surface vibration. This suggested that at the head, the perceptual mechanisms of vibration induced by high-level low-frequency noise were different from those in the trunk of the body.