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Inspite efforts of rebirthing engineering education degradation of student achievement is progressing due to several reasons. In particular, introducing accrediting system in each university has actually contributed to improve engineering education. However, math achievement of student having different study path is unclear. Taking into account the math knowledge inevitable for bachelor engineer, present author proposes a concrete desirable math knowledge on differentiation, integral, ordinal and extraordinal differential equation, vector, tensor and complex variables at graduation, derived from his teaching career at department of mechanical engineering.

The purpose of this study is to obtain mass, spray angle and velocity distributions of fragments in debris cloud generated by oblique impacts on an aluminum alloy plate. Hypervelocity impact tests were performed with a two-stage light gas gun at Kyushu Institute of Technology. The impact angles were changed to 0°, 15°, 30°, 45° and 60°. The projectile impacted on the targets at 2 km/s. After the impact, the debris cloud was taken with flash X-rays and an ultra high-speed video camera. The fragments were then captured in a stack of polystyrene sheets. As a result, the projectile was broken up into smaller fragments by oblique impacts with the larger impact angles. Lower velocity fragments dispersed in wider spray angles according to the increase of the impact angles.

Examining curriculum among universities revealed that no significant difference in math class or related subjects can be seen. However, amount and depth of those studies, in general, differed depending on content of curriculum and the level of achievement at entrance to individual university. Universalization of higher education shows that students have many problems in learning higher level of traditional math and that the memory of math they learned quickly fades away after passing in exam. It means that further development of higher math knowledgebased engineer after graduation from universities. Under these circumstances, the present author, as one of fun of math, propose how to maintain way of thinking generated by math knowledge. What necessary for engineer is to pay attention to common books, dealing with elementary mathematics or arithmetic- related matters. This surely leads engineer to nourish math/arithmetic knowledge-based way of thinking.

There is no effective protective measure against space debris between 1 and 10 cm in diameter. Debris in this size range can perforate the pressurized walls in the International Space Station (ISS). According to the current ISS operating procedures, crews must escape from a punctured module at once. However prompt detection of the perforation hole location is difficult in the current state of the ISS. Therefore it is important to install a detection system to the locate perforation hole on a space structure for both the quick decision of escape direction and repair location. In this study, we propose a perforation hole detection system for space debris impact. This system uses a resistance film attached to the pressurized wall as an area sensor. The effectiveness of this detection system was verified by numerical analysis and pseudo-perforation hole tests but also hypervelocity impact tests.

The purpose of this study is to investigate fragment clouds generated by hypervelocity impacts (HVIs) on metallic meshes. The HVIs tests have been conducted with a two-stage light gas gun facility at Kyushu Institute of Technology. Projectiles were launched at 3 km/s. Radiographs of the fragment cloud generated by the impact of the projectile on the mesh were taken with three flash X-rays. As a result, it was found that the velocity of the fragment cloud at the cloud center of gravity was up to 35% slower than the impact velocity of the projectile.

– Objectives: The aim of this study was to determine associations of lifestyle with dental health behaviors such as tooth brushing frequency, use of extra cleaning devices, and regular dental visits to a dentist. Methods: Data were collected from 1182 dentate residents 18 years of age or older who resided in a typical farming district. The data included data on the demographic factors, dental health behavior, and various aspects of lifestyle, i.e. mental condition, alcohol consumption, smoking habit, physical activity, social activity, dietary habits, and presence of systemic diseases. Results: Multiple logistic regression analysis revealed that subjects in a younger group (18–39 years of age) and subjects who had never smoked brushed their teeth more frequently. Experience of social volunteer work and presence of systemic disease were correlated with use of extra cleaning devices. Associations of female gender with frequency of tooth brushing and use of extra cleaning devices were weakly positive. The subjects who considered dietary combination carefully and those who lived alone were predisposed to visit a dentist regularly. Conclusions: The results indicate that dental health behavior is associated with lifestyle as well as demographic factors.

The data from a series of low-velocity collision experiments performed at Kyushu University will be re-analyzed based on the method used in the National Aeronautics and Space Administration (NASA) standard breakup model 2000 revision to be compared with the hypervelocity collision model adopted in the NASA standard breakup model. The results will indicate that the NASA hypervelocity collision model can be applied to low-velocity collisions possible in the geosynchronous regime with some simple modifications.

We have conducted research related to space debris issues, including impact experiments associated with visualization of fragment creation processes. However, we aim at those phenomena in the geosynchronous regime where the impact velocity is far lower than hypervelocity. The research purpose is to understand dispersion properties of newly created fragments to be used in the eventual orbital dispersion and debris population models. At Kyushu University, the experiments had been carried out up to velocity of 300m/s so far. However, if debris in geostationary transfer orbits should be taken into consideration, the maximum impact velocity on geostationary satellites will become up to 1500 m/s. Therefore, the experiment in 300-1500 m/s is planed to be conducted using the Two-Stage Light Gas Gun at Kyushu Institute of Technology. The similarities and differences in the experimental results from Kyushu University and Kyushu Institute of Technology are discussed.

Drastic changes in society, such as quick globalization, few baby and eldering society, world wide mega competition in industries, rebuilding and shifting industrial production activity to modern and only one-oriented key technology, inevitably brings a strong demand for changing traditional education system. This paper delas with a quick summary of observing results about what has been happening outside university from a view point of education after rebirth of the world in 1990. Peer view about possibility of promoting collaborative work of engineering education between university and company is also discussed.

Mode III fatigue crack is usually observed at the root of circumferentially notched round bar. As the crack grows in the depth direction of specimen, the growth rate of crack decreases. In this respect, crack mode transition from mode III to mode I is understood responsible. However, quantitative evaluation on crack mode transition has been hardly done. Therefore, values of stress intensity factor KI under mode III fatigue crack growth tests on a low carbon steel were calculated with using principal stress, as crack mode transition began. Then KI values were compared with crack growth rate curve of mode I. As the result, it was observed that the condition of crack mode transition was given by the crack growth rate curve of mode I.

To examine the interaction of sodium intake with genetic variations of the angiotensinogen gene and hypertension.A community-based case-reference study.Two rural Japanese communities.Non-overweight and non-drinking Japanese men and women: 229 hypertensives and 229 age-, sex- and community-matched normotensives aged 32 to 83 years.Polymorphisms of the angiotensinogen gene detected by an allele-specific polymerase chain reaction. A priori hypothesis is individuals with 174M (threonine-to-methionine substitution) or 235T (methionine-to-threonine substitution) allelic variations may have an elevated risk of hypertension when they have a high sodium intake, estimated by 24-h urine collection and a dietary questionnaire.The genotypic frequency of the haplotype including both the 174M and 235T alleles was higher among hypertensives than among normotensives (23 versus 14%, P= 0.02). The frequency of the 174M allele was specifically higher among hypertensives than normotensives (12 versus 7%, P=0.01), and the odds ratio of hypertension associated with the 174M (versus 174T) allele was 1.8 [95% confidence interval (CI) 1.1-3.0, P=0.01]. The frequency of the 235T allele did not vary between the two groups (80 versus 82%, P= 0.40). The relationship between the 174M allele and hypertension was more evident among persons who had higher urinary sodium excretion (= 166 mmol/day) than those with lower excretion (166 mmol/day): odds ratio 2.5 (95% CI, 1.2-5.2), P=0.01 versus 1.5 (95% CI, 0.7-3.1), P= 0.31; P for interaction = 0.04, and this trend was primarily observed for early-onset hypertension (55 years at onset). A similar but nonsignificant association was observed when stratified using present and past sodium intake scores derived from questionnaires.Angiotensinogen genotype may affect the development of early-onset hypertension among Japanese, particularly in those who have a high sodium intake.

In order to examine the mechanism of so-called fish eye-pattern fatigue failure, usually being caused by initiation and growth of internal small crack, uniaxial push-pull fatigue tests were carried out on a high strength low alloy steel in vacuum, for modifying the environment during internal crack initiation and growth on specimen surface. The test results showed that the fatigue life was elongated and the crack growth rate was delayed in vacuum. Furthermore, the results of fractographic observation of crack initiation at inclusions revealed that the surface type crack initiation in vacuum resembles the internal fish eye-type crack initiation in atmosphere. Finally the fish eye-type fatigue life was well evaluated in terms of small crack growth law in vacuum.

In a previous paper, the present authors clarified that COD is a suitable parameter to interpret the fatigue damage on the basis of the fatigue crack growth in low-cycle random fatigue. Especially the COD parameter correlated well the fatigue damage counted using the rainflow method (RFM) with the crack growth life in LCF. To extend this idea to high-cycle random fatigue the present study has been done. The result showed that although the RFM is valid to evaluate total fatigue life, it is invalid to predict the crack growth life. This is due to the fact that the crack growth life is strongly affected by the effect of crack closure, which is more amplified in high-cycle fatigue than low-cycle fatigue.

The rain flow method (RFM), widely used as one of the useful fatigue damage counting methods, was re-examined in conjunction with the actual fatigue process such as crack initiation and propagation. The low-cycle fatigue tests were conducted on a mild steel under variable strain amplitude. A special attention was paid to correlate the fatigue life controlling-volumetric parameter, plastic strain range Δep, with a fracture mechanics parameter ΔCTOD. Then, a physical meaning of RFM was given on the basis of small crack growth law. The experimental results of the variable strain amplitude fatigue tests showed that the trend of the change of the value Δep was similar to that of ΔCTOD. In addition, the small crack growth rate versus ΔCTOD showed a linear relationship.

Uniaxial push-pull High Cycle Fatigue (HCF) tests as well as Low Cycle Fatigue (LCF) tests were conducted on a medium carbon steel under constant stress or strain amplitude. To examine the small crack growth behavior, a small drilled hole of 50μm in diameter and in depth was introduced on each specimen surface. A fracture mechanics parameter, suitable for characterizing fatigue crack growth rate in both fatigue regions was examined. The results showed that the cyclic crack tip opening displacement range (ΔCTOD), which can well be correlated with overall cyclic plastic strain range Δep, was a suitable parameter to describe the fatigue crack growth rate in both fatigue regions.

The molecular dynamics simulation of fracture process under static and fatigue loading were done on a nano-scale polycrystal of pure iron, proposed in a previous paper. In the static tension, increasing tensile strain promoted the slip band formation near the grain boundary and finally resulted in microcrack initiation. Formation of subcracks and their growth along grain boundary layer dominated the fracture process at 100K. A large-scaled slip band formation along each grain boundary was observed in the simulation at 700K. The temperature-dependence of fracture process explained well the transition from the cleavage or brittle fracture to the ductile one. Regarding to the fatigue simulation, the fatigue life was decreased with increasing cyclic stress amplitude. At higher stress amplitude, many subcracks were simultaneously formed at the grain boundary and the final failure was dominated by the growth and coalescence of those subcracks. On the other hand, the fatigue fracture was controlled by the primary growth of a single crack formed among the subcracks at lower stress level.

A molecular dynamics parameter (MDP), which J-integral is expanded to, is proposed for a molecular dynamics (MD) fracture simulation and is applied to a two-dimensional α-iron problem under simple tension. For this model a pair potential described by a polynomial expression is chosen as an interatomic potential. Closely packed lattice structures are assumed in the present calculation. The edge crack arranged in the middle of the analysis body is perpendicular to the tensile loading direction. The brittle fracture is analyzed under the fixed displacement boundary condition in the tensile deformation process. MDP1 is calculated on several paths similarly to J-integral. MDP1 increases slowly before fracture and decreases steeply after that in any path. In order to investigate the validity of MDP1 the critical stress intensity factor KMDPIC is calculated. KMDPIC corresponds well with the decelis and Mullins KIC. MDP value can be applied to an estimation of the initial stage of macroscopic fracture phenomenon with high reliability.

The low frequency pulsed MIG welding process of new current waveform control to switch over unit pulse conditions (pulse current, pulse duration) in the fixed cycle was developed and its effect were investigated for aluminium and its alloy.By using this new welding process, the bead appearance having clear ripple pattern, such as TIG welding bead can be obtained and the gap tolerance of lap and butt welding joint can be expanded.

An interferometric strain/displacement gauge (ISDG) system with a laser diode was developed to measure dynamically the crack closure behaviour of a small surface crack. Two Vickers indentations, about 100 μ apart, were illuminated with the laser pulse synchronized with the load signal. The interference fringe patterns moved as the indentation moved apart. The 95% confidence limit, obtained on the basis of the difference between the strain measured by the ISDG and that by the resistance strain gauge (RSG), was ±6.0 × 10−4μ for stepwise loading. The standard deviations of the relation between stress and displacement under elastic conditions were 1.7 for stepwise loading at 0.067 Hz and 2.6, 2.6, 2.3 for dynamic loading at 5, 10 and 20 Hz respectively. The crack mouth opening displacement was measured dynamically as well as statically with the system. The crack opening stress was determined using the unloading elastic compliance method. The measuring frequency hardly affected the crack opening stress. Smooth specimens of a type 304 austenitic stainless steel were fatigue tested. The crack propagation behavior was observed and crack closure measurements monitored for crack lengths ranging from 0.12 to 0.75 mm. The aspect ratio of the surface crack was determined on the basis of the relation between the surface crack length and the elastic compliance. The relation between the crack propagation rate and the J integral range was unique, and agreed well with that calculated by the effective stress intensity range for long cracks.

Chronic and excessive consumption of alcohol is an important factor responsible for the onset of pancreatitis. However, the incidence of chronic pancreatitis in heavy drinkers differs in individuals, suggesting that these individual differences may involve various genetic and environmental factors. In the present study, we investigated an association of alcoholic pancreatitis with polymorphisms of the various genes related to metabolism of the oxidative compounds. We analyzed polymorphisms of NADPH-quinone oxidoreductase 2 (NQO2), multidrug resistance 1 (MDR1), alcohol dehydrogenase 1B (ADH1B) and lipoprotein lipase (LPL). The subjects consisted of 53 patients with chronic alcoholic pancreatitis (AlCP), 54 alcoholic patients without pancreatic dysfunction (Alc), and 42 healthy individuals. DNA samples were prepared from the peripheral blood of all subjects, and the genetic mutations were analyzed by polymerase chain reaction and restriction fragment length polymorphism methods. The ADH1B gene frequencies were significantly different between healthy controls and Alc patients (P0.001), and also between AlCP and Alc patients (P0.05). However, no significant difference was found between healthy controls and AlCP patients. The gene frequencies of MDR1 (3435CT) and MDR1 (2677GA/T) of patients with AlCP or Alc were different when compared with healthy controls, although the difference was not significant. The NQO2 and LPL genes showed no relation with Alc and AlCP patients. The ADH1B*1 gene frequency in AlCP was significantly lower compared with Alc. We speculate that the ADH1B*1 gene may function by reducing vulnerability to the onset of alcoholic pancreatitis. Other genes analyzed in the present study lacked association with AlCP.

The intermaxillary fixation (IMF) has been frequently applied to maxillofacial fractures. The period of the fixation is however, determined empirically because we have no barometers to judge the bone unions. Thus, a method capable of determining an appropriate time of IMF removal in each case has been sought.The authors developed a new measurement apparatus for analyzing the transmission of vibration based on Coherence function, and bound that this apparatus could be a useful tool for the determination of the time of IMF removal. The apparatus is characterized by its abilities to judge the bone unions and to evaluate the healing process of mandibular fractures through a non-invasive and periodical measurement.In this paper, we report that our method was quite useful in evaluating the healing process, even in the mandibular fracture case of abnormal hone healing which was bruised and infected at the fracture site during IMF.

A case of metastasis to the lateral lingual lymph nodes in a patient with tongue cancer is reported. The patient wase a 73-year-old man with a moderately differentiated squamous cell carcinoma of the left lingual margin (T 3 N 2 bM O). Metastasis to the lateral lingual lymph nodes was detected by computed tomography and magnetic resonance imaging preoperatively. After external radiation, bilateral neck dissection and hemiglossectomy were performed by a pull-through operation. Histopathological examination revealed that the lateral lingual lymph nodes had been extensively degenerated by the radiation.

To develop a new sensitive and inexpensive hepatitis C virus (HCV) combination test (HCV Guideline test) that enables the determination of HCV genotypes 1, 2 and 3, and simultaneous determination of HCV viral load using commercial Amplicor GT HCV MONITOR test v2.0 (microwell version).The HCV Guideline test used the PCR product generated in commercial Amplicor GT HCV Monitor test v2.0 for viral load measurement using microwell plate version of Amplicor HCV Monitor and also captured on separate plates containing capture probes and competitive oligonucleotide probes specific for HCV genotypes 1, 2 and 3, The HCV genotype was subsequently determined using the biotin-labeled PCR product and five biotin-labeled HCV-specific probes.The sensitivity of the HCV Guideline test was 0.5 KIU/mL. Specificity of the HCV Guideline test was confirmed by direct sequencing of HCV core region and molecular evolutionary analyses based on a panel of 31 samples. The comparison of the HCV Guideline test and an in-house HCV core genotyping assay using 252 samples from chronic hepatitis C patients indicated concordant results for 97.2% of samples (59.5% genotype 1, 33.7% genotype 2, 6.0% genotype 3, and 0.8% mixed genotypes). Similarly, the HCV Guideline test showed concordance with a serological test, and the serological test failed to assign any serotype in 12.7% of the samples, indicating a better sensitivity of the HCV Guideline test.Clinically, both viral load and genotypes (1, 2 and 3) have been found to be major predictors of antiviral therapy outcome regarding chronic hepatitis C based on guidelines and they are, in normal circumstances, performed as separate stand-alone assays. The HCV Guideline test is a useful method for screening large cohorts in a routine clinical setting for determining the treatment regimen and for predicting the outcome of antiviral therapy of chronic hepatitis C.

Kyushu University has performed some low-velocity impact experiments at a lowvelocity range less than 300 m/s to understand the dispersion properties of fragments newly created by a low-velocity collision possible in geosynchronous Earth orbit (GEO). The data from those impact experiments are utilized to establish a mathematical prediction model to be used in debris generation and propagation codes. The author re-analyzed the experimental data based on the method used in the National Aeronautics and Space Administration (NASA) standard breakup model and compared the reanalyzed results with the NASA standard breakup model. The comparison indicates that the NASA standard breakup model can be applied to lowvelocity collision with some simple modifications. Currently, we are performing additional impact experiments using a two-stage light gas gun at Kyushu Institute of Technology (KIT) to verify the modifications and exam their applicability at a slightly higher velocity range up to 800 m/s, that is the maximum relative velocity between GEO objects. In this paper we will present the results from our additional low-velocity impact experiments performed under collaboration between Kyushu University and KIT.

Background The human NOTCH4 gene is a candidate gene for schizophrenia due to its chromosomal location and neurobiological roles. In a British linkage study, NOTCH4 gene polymorphisms were highly associated with schizophrenia. In a Japanese case-control association study, however, these polymorphisms did not show significant associations with schizophrenia. We conducted a case-control study with Japanese subjects to explore an association between the triplet repeat polymorphism in the NOTCH4 gene and schizophrenia, including subtypes of schizophrenia, longitudinal disease course characteristics, and a positive family history for psychoses. Methods We examined the (CTG)n repeat polymorphism in the NOTCH4 gene among 100 healthy Japanese individuals and 102 patients with schizophrenia (22 paranoid, 38 disorganized, 29 residual, 64 episodic, 31 continuous, 42 with prominent negative symptoms, and 46 with positive family histories) using a polymerase chain reaction-based, single-strand conformational polymorphism analysis. Results Five different alleles consisting of 6, 9, 10, 11, and 13 repeats of CTG (Leu) in patients with schizophrenia, and 4 alleles consisting of 6, 9, 10, and 11 repeats in controls were found. No significant differences in genotype or allele frequencies of repeat numbers were found between controls and patients. In addition, there were no associations between the polymorphism and schizophrenia subtypes, longitudinal disease course characteristics, or positive family history of the patients. Conclusions Our data suggest a lack of association between the NOTCH4 gene triplet repeat polymorphism and schizophrenia in Japanese individuals.

Recent studies suggest that Parkinson's disease (PD) is associated with particular personality traits. Using Cloningers's Tridimensional Personality Questionnaire (TPQ), Menza and colleagues [1993: Neurology 43:505-508] reported a possible association between PD and a reduced score in the novelty seeking (NS) dimension of the TPQ. We sought to determine whether this association, which was found in a study conducted in the United States, could also be found among Japanese PD patients. We performed personality assessments of 67 Japanese PD patients, using the TPQ test. The results suggest that Japanese PD patients have significantly lower scores in the NS dimension of the TPQ, as well as significantly higher harm avoidance (HA) scores, compared with matched control subjects. Furthermore, the PD patients undergoing treatment for depression using antidepressant drugs scored significantly higher in the HA dimension than PD patients who did not receive antidepressant drug treatment. Our results suggest that the high HA score, and the low NS score in the TPQ test observed in patients with PD, is a cross-cultural phenomenon, although the influence of depression, long-term treatment, and premorbid gene/environmental interactions may also affect these personality traits. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:1-3, 2000.

AIM: To develop a simple and accurate method for quantifying 8-isoprostane in plasma by employing a combination of two-step solid-phase extraction of samples and a commercially available ELISA kit, and by this method to examine the effects of drinking and smoking habits against the levels of plasma 8-isoprostane in healthy Japanese volunteers. METHODS: Plasma 8-isoprostane was extracted with ODS gel suspension followed by NH2 Sep-Pak column. The 8-isoprostane fractions were assayed using a commercially available ELISA kit. We measured plasma 8-isoprostane levels in 157 healthy Japanese volunteers divided into three groups (64 non-habitual drinkers, 56 moderate drinkers and 37 habitual drinkers) according to their alcohol consumption per week. Genotypes of aldehyde dehydrogenase 2 (ALDH2) were also determined to investigate the plasma 8-isoprostane levels with reference to drinking habits. In addition, the plasma 8-isoprostane levels of 96 non-smokers and 61 smokers from the same subjects were compared. RESULTS: Our method fulfilled all the requirements for use in routine clinical assays with respect to sensitivity, intra- and inter-assay reproducibility, accuracy and dynamic assay range. Significant increases of plasma 8-isoprostane levels were observed in female habitual drinkers when compared with those of non-habitual drinkers (t = 5.494, P < 0.0001) as well as moderate drinkers (t = 3.542, P < 0.005), and 8-isoprostane levels were also significantly different between ALDH2*2/1 and ALDH2*1/1 in the female habitual drinkers (t = 6.930, P < 0.0001), suggesting that excessive drinking of alcohol may increase oxidization stress, especially in females. On the contrary, no significant difference of the plasma 8-isoprostane levels was observed between non-smokers and smokers. CONCLUSION: Our present method was proved to be a simple and accurate tool for measuring plasma 8-isoprostane. However, the clinical utility of plasma 8-isoprostane for drinking and smoking habits was limited since elevated 8-isoprostane levels were observed in female heavy drinkers, and no association was found between smokers and nonsmokers.

Effect of disturbance due to material inhomogeneity and that of anisotropy on the path of crack propagation in brittle material are analyzed by the body force method. Disturbance is characterized by two factors, i.e. one is the magnitude and the other is the density of disturbance in materials. When a straight crack on x-axis propagates in a plate under biaxial tension (σx∞, σy∞), the path of crack propagation is influenced by both the ratio of σx∞ to σy∞ and the disturbance. When σx∞/σy∞≥10, the total path of crack propagation is almost entirely determined by the magnitude of disturbance at the start of propagation. When σx∞/σy∞ 5, the intermediate phenomena between σx∞/σy∞=2 and 10 occur. Even the weak anisotropy of KIC remarkably influences the path of crack propagation. The experimentally obtained path of fracture of a circumferential surface crack in a pressurized acrylic cylinder can be explained only by considering the anisotropy of KIC.

Fatigue damage accumulation induced by rotating bending (RB) and cyclic torsion (CT) is examined on a low carbon steel. The effect to the load sequence on fatigue damage accumulation was investigated microscopically as well as macroscopically. The loading type of RB-to-CT switching strengthened the fatigue life of the second stress cycle, while the fatigue damage accumulated linearly in the case of CT-to-RB loading. This trend of load sequence effect on the fatigue damage accumulation is clarified through microscopic observation of the fatigue process. The fracture mechanics-aided interpretation of the microcrack growth behavior from the slip band cracking to visual crack also supports this tendency.

In order to investigate low-cycle fatigue life on the basis of serial observation of microcrack initiation and propagation, cyclic strain controlled-low-cycle fatigue tests were carried out on unnotched specimens. Either constant or two step strain amplitude was selected in experiments. It was found that the unnotched low-cycle fatigue process is dominated by the microcrack growth. The microcrack growth rate is proportional to a crack length. From those experimental evidence, the Manson-Coffin relation is derived using microcrack propagation law. Moreover, in case of two step strain cyclig, the prior fatigue history hardly gives effect on the subsequent microcrack growth. Combining such results as mentioned above, the Miner rule is found another indication of the microcrack propagation law.

The phenotypic distribution and gene frequencies of haptoglobin (Hp), transferrin (Tf), group specific component (Gc), cholinesterase (Cho E2), and alpha1-antitrypsin (Pi) in plasma proteins, and phosphoglucomutase (PGM), 6-phosphogluconate dehydrogenase ((6-PGD), esterase D (Es D), phosphohexose isomerase (PHI), adenosine deaminase (ADA) and acid phosphatase (AcP) in red cells were studied in 127 atopic, asthmatic patients. The gene frequencies were compared with normal groups. The phenotypic distribution of the Pi system in atopic patients was somewhat different from the normal. No significant differences were found between the two groups in protein systems or in enzyme systems, except Pi systems. In conclusion, except for the Pi system, no definite association between polymorphic traits and atopic asthma was found in this study.

The microcrack growth law-oriented approach developed in a previous paper is applied to examine the fatigue strength and mechanism of 200 mm and 100 mm thick forged steel plates. Low-cycle fatigue tests are conducted on specimens sliced in the transverse (T) and thickness (S) directions of the plates. Through continual observation of the fatigue process, the effect of elongated inclusions on microcrack initiation and propagation behaviors is elucidated. The fatigue life is shorter in the S than in the T direction. The fatigue lives in both directions are evaluated on the basis of the microcrack propagation law. The elongated inclusions hardly affect the fatigue process in the T direction, while they show a strong influence in the S direction. The fatigue process is dominated by a monotonous growth of a leading crack in the T direction. On the contrary, the leading crack growth in the S direction is governed by a joining of subcracks.

Nominal stress-controlled low-cycle fatigue life under imposed mean stress is affected by elongation or contraction due to cyclic stress-induced creep. Therefore, the effect of mean stress was examined by a microcomputer-assisted testing device which provides true stress controlled loading. Through investigation of a medium carbon steel (S45C), the following results, were obtained:(1) Cyclic plastic strain amplitude at the steady cyclic stress-strain state decreased with an increase of the imposed tensile mean stress.(2) The cyclic stress-induced creep proceeded so far as the mean stress was imposed. The increase in axial cyclic creep strain per cycle was proportional to the nth power of the maximum cyclic stress.(3) For the same cyclic stress amplitude, the application of tensile or compressive mean stress prolonged the fatigue life as compared with the fully reversed stressing.(4) A modified Manson-Coffin relation including such two parameters as the cyclic stress amplitude and the mean stress was proposed for evaluating the fatigue strength under cyclic stress-induced creep condition.

The effect of torsional prestrain on tensile and low-cycle fatigue properties of a medium carbon steel was studied. A series of small-sized tensile and fatigue specimens were prepared from large-sized prestrained specimens in order to ensure good homogeneity of the torsional prestrain in the cross-section of the small-sized specimens. Three modes of prestraining were selected in this study; unidirectional, twistback, and single- or cyclic-reversed torsion. Fracture ductility decreased almost linearly with increasing unidirectional prestrain, while the decrease of fracture ductility in the other modes of prestrain was much less than that in the unidirectional one. A transitional decrease in fracture ductility, which has been reported for inhomogeneously prestrained specimens, was not observed in this study. A slight trace of recovery in fracture ductility due to twisting back the unidirectional prestrain to the macroscopically undistorted original state was observed, in contrast with the almost complete recovery for the inhomogeneously prestrained specimens. The low-cycle life of the unidirectionally prestrained specimens was reduced by an amount which would be predictable from the decrease in fracture ductility of those specimens. For other modes of prestrain, however, the influence on fatigue life was undistinguishably small in this study.

In order to gather information relating to the low-cycle fatigue behavior of anisotropic materials, the low-cycle fatigue prorerties of thick rolled steel plates were investigated in several directions under the condition of uniaxial tension-compression. The steel plates used showed considerable anisotropy in fracture ductility in the thickness direction, while anisotropy in the yield and ultimate tensile strengths was observed to be very slight in any direction. The low-cycle fatigue behavior was also the most anisotropic in the thickness direction. The fracture life in a given direction, however, was found to follow the Manson-Coffin type relation, which is usually applied to isotropic materials, if the fracture ductility determined from the tensile test in that direction was used. The crack initiation life also exhibited a similar trend, although in a more exaggerated manner. Differences were found in fracture mode depending on the directions relative to the rolling direction.

The biaxial low-cycle fatigue properties of anisotropic rolled steel plates were investigated. Biaxial low-cycle fatigue tests were conducted by utilizing the principle of anticlastic bending of flat rhombic plates. Crack initiation and propagation were examined with special reference to angles between the applied principal stress axes and the anisotropy axes of the material studied. The biaxial fatigue life of anisotropic specimens cut out in a given direction satisfied a linear relation on a log-log scale between an equivalent strain range and the number of cycles to failure. The direction of crack initiation under the uniaxial and biaxial stress conditions was coincident with that of the maximum shear stress. The fatigue life under the uniaxial stress condition was shorter than that determined under the biaxial stress condition for a given value of the equivalent strain range. The discrepancies were interpreted in terms of both normal stress component acting on the crack surface and the modes of crack propagation.

The microcrack growth law-aided approach previously developed by the present authors is first applied to examine the directionality or anisotropy in fatigue strength of thick forged steel plates with a different forging ratio. Fatigue tests are conducted on specimens sliced in the transverse (T) and thickness (S) direction of the plates. Through continual observation of the microcrack initiation and propagation processes, the elongated manganese-sulphide (MnS) inclusions are found to hardly affect the fatigue processes in T direction, while they strongly influence upon them in S direction.