Senko Medical Instrument Manufacturing (Japan)

Abstract One of the features of Japanese structural steel design is an economical design option for yielding exposed column bases before first‐story columns, namely weak‐base/strong‐column design, which is unlike the strict capacity design for column bases. This study aims to develop a repair methodology that identifies damage states of the yielding column bases and anchor rods, and selects appropriate repair/retrofit methods. As a standard repair method for damaged exposed‐type column bases, the applicability and effectiveness of the re‐tightening process of anchor rods need to be examined. This study first reviews the literature on standard retrofit techniques for column bases and required deformation capacity of ductile anchor rods. The threaded anchor rod deformation capacity with different steel grades and screw threads commonly used were tested to clarify the required ductility. To clarify the reparability of exposed column bases, numerical models of four‐ and six‐story steel moment resisting frame buildings were developed and validated by shaking table test results. The results show that this simple repair method was proven to be effective through the test program and numerical analysis and it's not always applicable for standard anchor rods assumed for pin or fixed column bases designed to remain elastic. Finlly, a repair methodology and flow chart that identifies the damage states of anchor rods and selects appropriate repair/retrofit methods for the exposed steel column base was suggested and applied to the simulation results.

This paper discusses fuse interrupting tests under 4000 V DC with low inductance. For the fuse breaking tests, the I2 current of IEC269 requires a pre-arcing of approximately 3 ms and arcing time about 5 ms with a transition time less than 1% of the total operation time. By contrast, in a case of short-circuit of a voltage source inverter, the current with very high di/dt occurs because of capacitor discharge with a very low inductance current loop. In this paper, to confirm the fuse breaking under very high di/dt condition, 3 large rated current fuses are connected in parallel and the breaking tests under 4000 V DC are validated in experiments. Finally, in a term of the fuse pre-arc i2t, the experimental results and the calculation using a simple model are compared.

Decreasing hemolysis and thrombogenesis is a major problem to realize the long-term use of blood pumps. In this study, we investigated the effect of discharge angle on pump properties of a monopivot centrifugal blood pump. Compared impellers had the same diameter, and they varied the discharge angle of the impeller which were 22.5°, 45°, 67.5°, and 90°. The axial thrust on the impeller, the estimated hemolysis index and the stagnation area around the pivot were calculated using computational fluid dynamics analysis. The pump driving condition was set at a flow rate of 4 L/min and a pressure head of 200 mmHg to simulate an extracorporeal circulatory condition. As a result, the rotational speed of the impeller was the lowest when the discharge angle was 90°. Although the axial thrust was the negative largest when the discharge angle was 22.5°, it was also kept negative for the other models, which indicated that all impellers will never lift off. The estimated hemolysis index was the lowest when the discharge angle was 22.5°, because high shear stress region around the outlet of the flow path was the smallest despite the rotational speed of the impeller was the highest. The stagnation area around the pivot was the smallest when the discharge angle was 22.5° because the flow rate through the washout holes was the largest due to the highest rotational speed of the impeller. Therefore, it was predicted that low discharge angle of the impeller improves both hemolytic and anti-thrombogenetic properties in the blood pump without considering other factors such as sliding of bearing and so on.

The effect of the impeller geometry of the centrifugal blood pump whose impeller rotates with a single-contact pivot bearing on the rotational stability against the hydrodynamic force was investigated. Two types of impeller were compared which were the FR model whose flow path had both front and rear cutouts on the tip, and N model whose flow path was straight. First, the axial thrust and moment was calculated by CFD analysis. Next, the impeller levitation and the impeller tilt were measured experimentally. As a result, the axial thrust of FR model decreased gently as the flow rate increase which was caused by smaller velocity in the top gap that resulted higher pressure in the top gap. The impeller tilts were less than 0.8 ° in both models which was considered to hardly affect the impeller stability.

SummaryInformation regarding signalment, clinical findings, treatment and outcome of 5 previously reported cases of anaplastic malignant melanoma of the tail in non‐grey horses and of 5 additional cases are summarised. Age was recorded for 9 horses and mean age was 16 years, range 8–23 years. Gender was recorded for 8 horses and 6 of these 8 horses were male horses over 14 years of age. The most common coat colour was bay (6 horses). Other coat colours were palomino (one horse), chestnut (one horse) and black (one horse); coat colour of one non‐grey horse was not specified. Follow‐up information was available for 9 horses and only one horse, a palomino, survived more than 10 months following diagnosis and tail amputation. Surgical excision, including tail amputation and medical therapy with oral cimetidine, was not effective in non‐grey, non‐palomino horses. Tumour recurred on tail tissue remaining after amputation in 2 horses, widespread metastases were documented in 4 cases and metastasis was suspected at the time of death or euthanasia in 3 cases, including one case with amputation site regrowth. No subjective histopathological differences were detected in the palomino horse that survived as compared to horses of other coat colours. Findings suggest that anaplastic malignant melanoma of the tail in non‐grey horses is most often a very aggressive neoplasm, but that there are rare exceptions.

We have developed a hydrodynamically levitated centrifugal blood pump for extracorporeal circulatory support as a bridge to decision pump. The impeller is levitated using hydrodynamic bearings without any complicated control circuit or displacement sensor. However, the effect of the outer circumferential velocity and the bearing area on the hemolytic property has not been clarified, even if the bearing gap is same size. The purpose of this study is to experimentally evaluate the effect of the outer circumferential velocity and the bearing area in the bearing gaps on the hemolytic property in a hydrodynamically levitated centrifugal blood pump. We prepared three models for testing. These models have the same bearing gap size by adjusting the impeller levitation position. However, the outer circumferential velocity of the impeller and the bearing area in the minimum bearing gaps are different. The outer circumferential velocity of the impeller and the bearing area were assumed to be related to the maximum shear rate and the exposure time. For the evaluation, we conducted an impeller levitation performance test and an in vitro hemolysis test. As a result, the normalized index of hemolysis (NIH) was reduced from 0.084 g/100 L to 0.040 g/100 L corresponding to a reduction in the outer circumferential velocity and a reduction in the bearing area, even if the minimum bearing gaps were same size. We confirmed that, even if the bearing gap was same size under the stably levitated condition, the outer circumferential velocity and the bearing area should be decreased in order to improve the hemolytic property.