High-density mesh flow computations by building-cube method

With the conventional computational fluid dynamics (CFD) approaches like unstructured high-density mesh method, the problem about the solution dependencies on the grid and on the physical models isn’t completely resolved. In this study, thus, a new approach named Building-Cube Method based on a Cartesian mesh is proposed using a high-density mesh in order to solve the problem of the current CFD approaches. In the present method, a flow field is divided into a number of cubes (squares in 2D) of various sizes. Each cube is a computational sub-domain with Cartesian mesh of equal spacing and equal number of nodes. The geometrical size of each cube is determined by adapting to geometry and flow features so as to cope with broadband characteristic lengths of the flow. Equal spacing and equal number of Cartesian mesh in each cube make it easy to parallelize the flow solver and to handle huge data output. The method is applied to several airfoils including NACA0012 and two-element airfoils at relatively low Reynolds number, RAE2822 airfoil with transition trip at high Reynolds number and a four-element airfoil at high Reynolds number. These results validate the capability of the present approach.     

Fabrication of heterostructures of halogen-bridged quasi-one-dimensional mixed-valence transition metal complexes

Single-heterostructure crystals of a series of halogen-bridged quasi-one- dimensional mixed-valence transition metal complexes (HMMCs) were fabricated by selective coordination epitaxial growth (SCE growth). The overgrowth crystals of the HMMC were grown on the columnar crystals of the substrate HMMC in solution. The single-heterostructure crystals were epitaxially grown only when the two HMMCs had similar crystal structures. If their crystal structures were different, no heterostructure crystal was grown. This result suggests that the degree of mismatch between the crystal structures of the substrate and the overgrowth is the predominant factor which determines the SCE growth of the HMMCs.     

40 Gbit/s packet bit error ratio and loss real-time measurement for ultrahigh-speed packet switched network

A novel packet bit error rate (BER) and loss measurement method and system is proposed. A proposed 40 Gbit/s packet BER and loss measurement system is expressed in detail. A 40 Gbit/s BER and loss measurement with various conditions is demonstrated experimentally. In real time, only the payload part of a packet and burst stream with fluctuated guard time is evaluated. The BER and packet loss of a randomly received packet sequence due to routing and buffering can be also evaluated by the measurement system. A 10 Gbit/s packet BER and loss measurement with optical label switching, buffering, and preamble-free optical packet 3R are demonstrated experimentally.     

An Antisense Oligonucleotide against a Splicing Enhancer Sequence within Exon 1 of the MSTN Gene Inhibits Pre-mRNA Maturation to Act as a Novel Myostatin Inhibitor

Antisense oligonucleotides (ASOs) are agents that modulate gene function. ASO-mediated out-of-frame exon skipping has been employed to suppress gene function. Myostatin, encoded by the MSTN gene, is a potent negative regulator of skeletal muscle growth. ASOs that induce skipping of out-of-frame exon 2 of the MSTN gene have been studied for their use in increasing muscle mass. However, no ASOs are currently available for clinical use. We hypothesized that ASOs against the splicing enhancer sequence within exon 1 of the MSTN gene would inhibit maturation of pre-mRNA, thereby suppressing gene function. To explore this hypothesis, ASOs against sequences of exon 1 of the MSTN gene were screened for their ability to reduce mature MSTN mRNA levels. One screened ASO, named KMM001, decreased MSTN mRNA levels in a dose-dependent manner and reciprocally increased MSTN pre-mRNA levels. Accordingly, KMM001 decreased myostatin protein levels. KMM001 inhibited SMAD-mediated myostatin signaling in rhabdomyosarcoma cells. Remarkably, it did not decrease GDF11 mRNA levels, indicating myostatin-specific inhibition. As expected, KMM001 enhanced the proliferation of human myoblasts. We conclude that KMM001 is a novel myostatin inhibitor that inhibits pre-mRNA maturation. KMM001 has great promise for clinical applications and should be examined for its ability to treat various muscle-wasting conditions.     

Feasible method,utilizing density changes,for estimating in situ dynamic strength and deformation properties of sand samples

Laboratory tests and design reliability are directly controlled by sample quality. The frozen sampling (FS) method is useful for dynamic strength and deformation tests of undisturbed clean sand. However, it is very expensive and requires considerable equipment. The sample quality of Toyoura sands obtained from 48 mm and 75 mm samplers are scrutinized based on void ratio, dynamic strength and deformation properties through model and cyclic undrained triaxial tests. A conventional method for estimating in-situ dynamic strength and deformation properties of sand samples utilizing density changes is examined and the applicability of the proposed method is discussed for the samples obtained from Niigata sand deposits.The main conclusions obtained from this study are summarized as follows:(1) A conventional method for estimating in-situ void ratio (e₀), D_r, stress ratio (R_L20) in a 20 cyclic time frame and the initial modulus of rigidity (G₀) of sand samples utilizing density changes is proposed.(2) The in-situ R_L20 and G₀ estimated from the proposed method for sand samples from tube samplers were similar to those of frozen sampling and the in-situ modulus of initial rigidity was calculated from the secondary wave velocity for Niigata sand deposits.Therefore, dynamic strength and deformation properties changes, caused by sampling, can be modified appropriately to an in-situ condition by this proposed method.     

Burning Rate Augmentation of BAMO Based Propellants

Thermal decomposition and the burning properties of BAMO based propellants with HMX or AN/HMX have been investigated. The heat generated by the azide binder decomposition initiated and accelerated the thermal decomposition of HMX and AN. Ammonium perchlorate (AP) and lead stearate with carbon black significantly altered the mechanisms of the thermal decomposition and the burning properties of the HMX based propellants. AP showed an increase in burning rate with a slight decrease in burning rate pressure exponent. The lead catalyst yielded high value of the burning rate with the lowest pressure exponent. The ammonium dichromate also influenced the mechanisms of the thermal decomposition and the burning properties of the AN/HMX samples. The combination of ammonium dichromate and copper chromite was the most effective on the burning rate augmentation of AN/HMX based propellants. AN sublimed and evaporated from the condensed phase and mainly reacted exothermically in the gas phase HMX and AN/HMX based propellants showed smokeless burning characteristics in the small rocket motor combustion tests.     

A molten metal jet impingement on a flat spreading surface

ABSTRACT

In the event of a severe accident, past experiences such as Three Mile Island and Fukushima Daichi have shown that the reactor core of a light-water nuclear reactor, if not properly safeguarded, could go through a meltdown. This will be followed by the formation of a corium, a mix of molten fuel elements, and liquid metals from the Reactor Pressure Vessel (RPV). In the worst-case scenario, a melt through from the RPV can occur and lead to the spreading of the corium, in the form of a molten element’s jet impinging on a flat concrete structure of the Primary Containment Vessel (PCV). To enhance the decommissioning and the safety procedure, scope of the present article is to deepen the understanding of the phenomena involved in the mentioned scenario, mainly jet-instability and molten material spreading. In the present study, experiments were carried out, by using corium simulant materials such as Copper and Tin, to investigate the link between the instability of the gravity-driven molten metal jet and the impinging followed by its spreading over a flat area.     

Determination of hyoscyamine and scopolamine in serum and urine of humans by liquid chromatography with tandem mass spectrometry

A simple method was developed for the analysis of hyoscyamine and scopolamine in human serum and urine using liquid chromatography with tandem mass spectrometry (LC/MS/MS). Hyoscyamine and scopolamine in serum and urine were cleaned up with an Oasis HLB cartridge and a PSA cartridge. The LC separation was carried out on an ODS column, using linear gradient elution with 5 mmol/L IPCC-MS3-methanol as the mobile phase. The mass spectral acquisition was done in the positive ion mode by applying selected reaction monitoring (SRM). The recoveries of hyoscyamine and scopolamine were 86.0-105% from human serum and urine fortified at 0.2 ng/mL and 10 ng/mL. The detection limits of hyoscyamine and scopolamine were 0.02 ng/mL. Four serum and three urine samples of humans poisoned by eating Datura innoxia Mill. were analyzed by this method. Hyoscyamine and scopolamine were detected at the levels of 0.45-3.5 ng/mL in all serum samples and 170-670 ng/mL in all urine samples.     

Identification of genes from Aspergillus oryzae that are preferentially expressed in membrane-surface liquid culture

We identified 22 genes from Aspergillus oryzae that are preferentially expressed in membrane-surface liquid culture (MSLC), among which Ser/Thr protein kinase (aopk1) and phosphatase (aoppt) genes were cloned. We also revealed that aopk1 encodes a protein with an N-terminal sequence 150 amino acid residues longer than that predicted from the registered sequence in GenBank.