Modeling of numerical simulation and experimental verification for carburizing-nitriding quenching process

A model considering quantitative effects of diffused carbon and nitrogen gradients and kinetics of phase transformation is presented to examine metallo-thermo-mechanical behavior during carburized and nitrided quenching. Coupled simulation of diffusion, phase transformation and stress/strain provides the final distribution of carbon and nitrogen contents as well as residual stress and distortion. Effects of both transformation and lattice expansion induced by carbon and nitrogen absorption were introduced into calculating the evolution of the internal stress and strain. In order to verify the method and the results, the simulated distributions of carbon and nitrogen content and residual stress/strain of a ring model during carburized and nitrided quenching were compared with the measured data.

Yield and Water Use Efficiency of Green Maize Planted in Conditions Brazilian Semiarid

This study investigated the water use efficiency and yield for the production of green ears of corn subjected to irrigation with drip system and with potassium fertilizer levels in Sumé, Paraiba State, Brazil. The experimental design was a randomized design with four replications in a split plot design with six water slides (0.25 ETcp, 0.50 ETcp, 0.75 ETcp, 1.00 ETcp, 1.25 ETcp and 1.50 ETcp) and six doses of potassium (0, 20, 40, 60, 80 and 100 kg·ha-1). The maize hybrid AG 1051 was mechanically sown on 13/01/2012 and the spikes in the green stage (doughy grains) were harvested 67 days after planting. Water consumption for producing one ton of maize cobs in the slides 132, 264, 396, 528, 660, and 792 mm of water within all treatments of potassium fertilization increased, indicating that the WUE decreases with the increasing amount of water applied via irrigation. Therefore, it was observed that the water use efficiency average was 61.76 mm·t-1 (2.02 kg·m3), i.e. for each m3 of water used 2.02 kg of ears of corn were produced with default. The application of 680.64 mm of water and 72.14 kg·ha-1 potassium maximized the yield of ears, resulting in the maximum yield of ears of 10.82 t·ha-1.

The Effect of Functionally Graded Materials into the Sandwich Beam Dynamic Performance

The original purpose of FGMs was the development of super resistant materials for propulsion systems. In the present work, numerical and experimental techniques are used to investigate the dynamic behavior of generally laminated composited beams. In the numerical analysis, the laminated beam is modeled using the commercial finite element software ANSYS. In the experimental study the core and face materials of sandwich beam specimens are nylon/epoxy FGMs and pure epoxy laminates respectively. The dynamic behavior of the sandwich composite beam specimens with different fiber orientation was carried out using two dynamic excitation techniques, harmonic using harmonic response and impulse using hammer. The specimens were prepared in the following configurations, different orientation angles, different layers, and different thickness. The results reveal that the natural frequencies of sandwich beam were affected directly by the face materials. The natural frequency decreases with increasing fiber orientations of the nylon/epoxy face laminates. Increasing the thickness increases natural frequencies. This study concluded that it is useful for the designers to select the fiber orientation angle to shift the natural frequencies as desired or to control the vibration level.

Optimal Mode Decision Method for Interframe Prediction in H.264/AVC

Studies show that encoding technologies in H.264/AVC,including prediction and conversion,are essential technologies.However,these technologies are more complicated than the MPEG-4,which is a standard method and widely adopted worldwide.Therefore,the amount of calculation in H.264/AVC is significantly up-regulated compared to that of the MPEG-4.In the present study,it is intended to simplify the computational expenses in the international standard compression coding system H.264/AVC for moving images.Inter prediction refers to the most feasible compression technology,taking up to 60%of the entire encoding.In this regard,prediction error and motion vector information are proposed to simplify the computation of inter predictive coding technology.In the initial frame,motion compensation is performed in all target modes and then basic information is collected and analyzed.After the initial frame,motion compensation is performed only in the middle 8×8 modes,and the basic information amount shifts.In order to evaluate the effectiveness of the proposed method and assess the motion image compression coding,four types of motion images,defined by the international telecommunication union(ITU),are employed.Based on the obtained results,it is concluded that the developed method is capable of simplifying the calculation,while it is slightly affected by the inferior image quality and the amount of information.

Protective effect of the extract of Yi-Qi-Fu-Mai preparation on hypoxia-induced heart injury in mice

Yi-Qi-Fu-Mai(YQFM) is extensively used clinically to treat cardiovascular diseases in China. To explore the anti-hypoxia effect of the extract of YQFM preparation(EYQFM), the EYQFM(1.4, 2.8, and 5.5 g·kg-1·d-1) was assessed for its heart-protective effect in a chronic intermittent hypoxia(CIH) animal model(oxygen pressure 7%-8%, 20 min per day) for 28 days of treatment. Betaloc(0.151 6 g·kg^(-1)·d^(-1)) was used as a positive control. The histopathological analyses of heart in CIH mice were conducted. Several cardiac state parameters, such as left ventricular ejection fractions(EF), stroke volume(SV), expression of creatine kinase(CK), lactate dehydrogenase(LDH), superoxide dismutase(SOD), and malondialdehyde(MDA) were measured. The results showed that treatment with EYQFM markedly reversed swelling of the endothelial cells and vacuolization in the heart when compared with the model group. Further study demonstrated that EYQFM significantly improved ventricular myocardial contractility by increasing EF and SV. In addition, EYQFM inhibited the activity of CK, LDH, decreased the level of MDA and improved SOD activity. The results demonstrated that EYQFM significantly improved the tolerability of myocardium to hypoxia and ameliorated the cardiac damage in the CIH model.

Influence of ultrafiltration membrane on ophiopogonins and homoisoflavonoids in Ophiopogon japonicus as measured by ultra-fast liquid chromatography coupled with ion trap time-of-flight mass spectrometry

Ultrafiltration is one of the most fascinating technologies, which makes it possible to improve the quality of traditional medicines for application in the pharmaceutical industry. However, researchers have paid little attention to the effect of ultrafiltration membrane on traditional medicines chemical constituents. In this work, Ophiopogon japonicus(L.f) Ker-Gawl. was used as an example to illuminate the influence of ultrafiltration with different material and molecular weight cut-off(MWCO) membrane on natural chemical constituents as measured by ultra-fast liquid chromatography coupled with ion trap time-of-flight mass spectrometry(UFLC-IT-TOF/MS). Our results indicated that ultrafiltration membrane significantly impacted homoisoflavonoids, especially homoisoflavonoids that were almost completely retained on the polyethersulfone(PES) membrane. We also found that the larger number of aglycone hydroxy and sugar moiety in steroid saponins, the higher the transmittance. Furthermore, the passage rate(%) of ophiogenin type saponins was higher than that of others. The possible adsorptive mechanisms were hydrogen bonding, hydrophobic interactions, and benzene ring interaction by π-π stacking. In conclusion, it is crucial to choose appropriate ultrafiltration membrane based on the characteristics of produce products for application of ultrafiltration technique.