Reaction between Fe-C Binary Alloys and Liquid Zinc

Twenty binary Fe-C alloys with a full-annealed structure were immersed in a pure zinc bath at 733 K for 600 s to clarify the reactivity of pearlite structure with liquid zinc. The structure of an alloy layer formed was observed and its thickness and the quantities of iron reacted with zinc were measured. The results obtained are as follows: (1) The alloy layer formed on a steel containing carbon up to a eutectoid level consists of a gamma layer next to the steel base, followed by a delta 1 layer and a zeta layer, and many ternary carbide particles are found in the alloy layer, increasing in number in propotion as a carbon concentration increases. Many cementite projections are found at an alloy layer / steel base interface, and the zeta layer grows irregularly in a hyper-eutectoid carbon level. (2) The thickness of the alloy layer and the quantities of iron having reacted with zinc do not depend on the carbon concentration up to the eutectoid level. (3) Cementite disrupts into the ternary carbide particles, and these particles are placed on the straight or curved line, or are distributed sparsely, depending on the cementite size and its relative position to the alloy layer/steel base interface. (4) The reactivity of pearlite structure is comparable with that of ferrite structure in 733 K, 600 s immersion

Reaction between Fe-0.10mass%Si Alloy(s) and Zinc(1)

An Fe-0.10mass%Si alloy was immersed in the pure zinc bath for a time up to 6 ks at various temperatures ranging from 713 K to 873 K. The morphology of the alloy layer was observed, and the thickness of the alloy layer and the quantities of iron having reacted with zinc were measured. The total thickness of the alloy layer formed at temperatures ranging from 713 K to 753 K is thicker than that of one formed at higher temperatures. The temperature dependence of the quantity of iron remaining in the alloy layer is similar to that of the total thickness of the alloy layer. An iron mass loss is greater in the temperature range from 713 K to 753 K, and above 813 K, it increases with the immersion temperature. To obtain information on the silicon reactivity in hot dip galvanizing, the results obtained for the Fe-0.10mass%Si alloy were compared with those obtained for pure iron under the same conditions used in this study. The addition of 0.10mass% Si influences the Fe-Zn reaction in the temperature range from 713 K to 753 K. The alloy layer formed in this temperature range comprises a gamma layer, a delta 1 layer, and a zeta layer. The zeta layer formed in this temperature range is a (zeta+eta) mixture layer, and is composed of granular or columnar zeta crystals. The growth of the zeta layer obeys the linear time law, disobeying the diffusion controlled process. The delta 1 layer formed in the temperature range from 713 K to 753 K is constant. This causes the growth of the zeta layer to obey the linear time law. The rapid reaction between the Fe-0.10mass%Si alloy and liquid zinc in the vicinity of 713 K is the effect of added silicon that allows the formation of the (zeta+eta) mixture layer

Biological Effects of Narrow Band Pulsed Electric Fields

This paper describes the process of narrow band pulsed electric fields (NPEFs) and its effect on mammalian cells. The NPEF consists of a pulse modulated sinusoidal wave (PMSW), which allows delivery of well-defined electric fields in terms of frequency, field strength and deposition energy to the biological systems. 100 μs long sinusoidal electric fields with a frequency of 0.02, 2 or 50 MHz and field strengths of up to 2 kV/cm are applied to CHO cells with variation in the DNA density in the cells investigated by means of Acridine Orange assay. The experiments indicate that 50 MHz fields cause DNA degradation without cell membrane defects, while 0.02 MHz fields lead to an increase in membrane permeability which is similar to the effect known as electroporation. The intermediate frequency of 2 MHz influences both the membrane and DNA. It is demonstrated that the MHz range narrowband electric fields with the amplitude level of 1 kV/cm cause intracellular effects in mammalian cells

Parental Accompaniment in Operating Rooms Reduces Child Anxiety

Background: We believe that parental presence before the induction of anesthesia for surgery among children with a cleft palate/lip would be effective in mitigating their preoperative anxiety. Objective: We assessed the states of patients with a cleft palate/lip when their parents accompanied them into operating rooms and clarified their and their parents’ cognition using a questionnaire. Methods: Data were collected via nursing observation when patients and their parents entered the operating room. Furthermore, an anonymous questionnaire was administered to patients and parents after the operation regarding their feelings about parental presence in the operating room. Results: In total, nine patients cried when they entered the surgical room. Furthermore, six patients and three parents reported preoperative anxiety. In addition, eight patients agreed that they were satisfied with the presence of their parents before induction. Conclusion: Approximately half of the patients cried. However, the presence of parents before the induction of anesthesia was effective in reducing anxiety among most patients and their parents