In this study, we evaluated the effect of the CO2 or H2O gasification reaction on the mechanical property of the coke matrix by measuring the elastic modulus of the coke matrix before and after the ...gasification reaction. We also investigated the effect of the distribution of the elastic modulus in the coke matrix on the strength of the lump coke by conducting the fracture analysis for the coke model with porosity of 0–0.4 in which the distribution of the elastic modulus obtained by the experiment was reflected. The nanoindentation measurements of the elastic modulus of the coke matrix before and after the gasification reaction implied that the distribution of the elastic modulus in the coke matrix differs depending on the gasification agent. In the case of the CO2 gasification reaction, both the coke matrices with high and low elastic moduli were consumed by the gasification. On the other hand, in the case of the H2O gasification reaction, only the coke with an elastic modulus of over 30 GPa before the reaction was consumed by the gasification reaction. Also, the numerical results showed that the distribution of the elastic modulus in the coke matrix affects the strength of the coke model with low porosity whereas the one did not affect that with high porosity.
Purpose
Increasing numbers of women are opting to undergo non‐medical oocyte cryopreservation (NMOC). In this report, we present experience at our clinic and discuss NMOC in Japan.
Methods
We ...followed the progress of 403 women who underwent NMOC at our clinic between 2014 and 2021, totaling 592 reproductive cycles.
Results
In total, 61 women underwent oocyte warming and fertility treatment. Of these, 13 women gave birth to 14 children. The median age at first oocyte cryopreservation was 38.3 years, and the oldest pregnant woman was 42 years. Most clients (60%) were in their late 30s. The median time between first oocyte cryopreservation and warming was 3.0 years. One woman was able to achieve a live birth with four vitrified oocytes.
Conclusions
This is the first report in Japan documenting pregnancies and childbirths resulting from NMOC. Ideally, women hope to achieve natural pregnancy between 20 and 32 years of age. NMOC is an option for individuals who are unable to pursue pregnancy during optimal reproductive years and wish to preserve their fertility for future attempts. NMOC is recommended in cases with few indications, and it is necessary to continue accumulating data on its long‐term safety and effectiveness.
A distributed activation energy model (DAEM) was applied to the kinetic analysis of CO2 and H2O gasification reactions for pulverized metallurgical coke. The results of the scanning electron ...microscopy observations and CO2 gas adsorption suggested that the gasification reaction occurs at the particle surface. Therefore, a grain model was employed as a gasification reaction model. The reaction rates of CO2 and H2O gasification were evaluated based on the DAEM. The activation energy changed as the reaction progressed and hardly depended on the particle size. The activation energies were 200–260 kJ/mol in CO2 gasification and 220–290 kJ/mol in H2O gasification. The frequency factor of H2O gasification was approximately 10 times larger than that of CO2 gasification, regardless of the progress of the reaction. At the same activation energy level, the frequency factor showed a higher value with a decrease in the particle size. This result was consistent with the theory of the grain model and indicated that the gasification reaction of the pulverized coke with a micrometer scale occurs on the surface of the coke particle. Furthermore, the value predicted by the DAEM was in good agreement with the experimental one.
In order to investigate coke degradation behavior due to CO2 gasification reaction in the blast furnace, mass transfer analyses with the reaction and stress analyses for coke considering its ...structure after the reaction were performed. Using the finite element method, CO2 gas diffusion in a coke lump and consumption of coke matrices owing to the gasification reaction were considered for the coke model in which the actual coke structure was reproduced. The rate-controlling step was also evaluated calculating the Thiele modulus and the effectiveness factor of catalyst obtained from CO2 concentration distribution in a coke lump. Further, stress analyses assuming a uniaxial tensile test were carried out for the coke model after CO2 gasification reaction, and the effect of the gasification reaction on a stress state in a coke lump was investigated. As a result, the reaction progressed mainly in the vicinity of the external surface with reaction temperature of 1673 K while it did uniformly in the whole coke lump with 1273 and 1473 K. Thus, the rate-controlling step shifted from the reaction-controlling step to the diffusion-controlling step with an increase in a reaction temperature, and the Thiele modulus and the effectiveness factor of catalyst also showed the same trend. From the stress analysis, coke strength decreased uniformly in the whole coke lump in case of the reaction-controlling step whereas it did mainly in the vicinity of the external surface in case of diffusion-controlling step.
Cryopreservation offers semipermanent embryo storage. Although there have been various reports on effects of cryopreservation, there are few regarding preservation for 10 years or more. Here, we ...describe the delivery of a healthy child to a mother 51 years old, using an embryo cryopreserved for 18.3 years. The patient had four cleaved embryos cryopreserved when she was 32 years old. After more than 18 years, a Day-3, 10-cell stage embryo was transferred during a hormone replacement therapy cycle. The patient became pregnant and gave birth to a healthy boy (3,046 g). This case demonstrates the potential for live births at advanced maternal age by cryopreserving embryos at a young maternal age. To our knowledge, this is the longest cryopreservation period reported for a birth involving transfer of the mother’s own frozen embryo.
Coke strength is an important property and generally evaluated with Drum Index (DI). It is considered that coke breakage occurs by two types of breakages during DI measurement, surface breakage and ...volume breakage. In this study, the cause of volume breakage was investigated by image analysis of cross-sectional image of coke before and after the DI measurement. As a result, a new image analysis method was developed. In this image analysis method, pore shape and coke-matrix connectivity were evaluated and new parameters “degree of Irregularity (I)” and “Connectivity Index (CI)” were proposed. I and CI represent pore shape and coke-matrix connectivity, respectively. By using this image analysis method, it was revealed that pore shape and coke-matrix connectivity were improved on adding HPC (High Performance Caking additive). By comparing the cross-sections before and after the DI measurement, it was found that the volume breakage occurred at the portions which have higher porosity, coarse pores, cracks and thin pore wall. Furthermore, it was clarified that the thickness of the pore wall broken by the DI measurement was < 7.6 µm thickness.
Hyper-coal process to produce the ash-free coal Okuyama, Noriyuki; Komatsu, Nobuyuki; Shigehisa, Takuo ...
Fuel processing technology,
07/2004, Letnik:
85, Številka:
8
Journal Article, Conference Proceeding
Recenzirano
Research and process development to produce the ash-free coal (Hyper-coal, HPC) has been carrying out since 1999. A new cost-effective process (Hyper-coal process) by the application of the solvent ...de-ashing technology can be adopted for the Hyper-coal process. Coal extraction rate achieved almost 70 wt.%daf (based on dry and ash-free coal) from some kinds of coals using two-ring aromatics as the recycle solvent. A gravity settling effectively removed insoluble residue from the solution. A flash separator recovered the solvent completely and produced Hyper-coal as a spherical fine particle, which containing several hundred PPM of ash. It was estimated that the calorie base cost of Hyper-coal would be competitive to a general coal price including its ash disposal cost in Japan.
Purpose
To find the best methods to achieve the highest pregnancy and birth rates for couples needing testicular sperm extraction (TESE)‐intracytoplasmic sperm injection (ICSI).
Methods
...Retrospectively studied were 801 patients with male factor infertility who had undergone TESE‐ICSI between April, 1996 and July, 2016 and who had been categorized into four groups: obstructive azoospermia (OA); non‐obstructive azoospermia (NOA); Klinefelter syndrome (KS); and cryptozoospermia (Crypt). The sperm retrieval rate, hormone levels, fertilization rate (FR), pregnancy rate (PR), and birth rate (BR) after ICSI among three groups were compared: fresh testicular sperm (FS)‐fresh oocytes (FO) (Group I); frozen‐thawed testicular sperm‐FO (Group II); and FS‐vitrified‐warmed oocytes (Group III).
Results
The testicular sperm recovery rate was 57.8% (463/801): 89.6% in the Crypt, 97.1% in the OA, 28.9% in the NOA, and 42.2% in the KS groups. The follicle‐stimulating hormone levels were significantly higher in the NOA and KS groups and the testosterone levels were significantly lower in the KS group. The FR, PR, and BR were: 65.2%, 43.2%, and 28.5% in group I; 59.2%, 33.4%, and 18.7% in group II; and 56.4%, 33.8%, and 22.1% in group III.
Conclusion
Intracytoplasmic sperm injection with FS‐FO achieved the best PR and BR. It should be considered what to do in cases with no testicular sperm by TESE. The authors hope that ICSI with donor sperm will be allowed in Japan in the near future.
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