Analysis of the advanced oxygenate water level control scheme of the engineering supercritical unit

The oxygenate water level is an important adjustment parameter in the operation of the fire generator set, and the water level may result in the safety of the water pump. The high water level will not only affect the oxygen effect, but it is also possible to cause the water shot to the steam turbine to cause a water shot or give the water tank full water, oxygenate vibration, drain and vapor with water. When the load is low (generally 35% rated load), the oxygenate water level is controlled by large and small valve, condensate pump variable frequency control condensed water drum pressure. When the unit load is high (greater than 35 rated load), the oxygenate water level is controlled by the condensed water pump, the large valve and small valve controls condensed water drum pressure.

Peculiarities of the influence of mitochondrial ATP-dependent K+ channels activation on the function of external respiration under experimental pneumonia

The studies were performed on male Wistar rats weighing 250-270 with experimental pneumonia (EP) induced by the method of A.M. Kulik. The animals were divided into the following groups: 1 – control; 2 - experimental pneumonia; 3 (first experimental group) - animals, which in parallel with the simulation of pneumonia were intraperitoneally administered uridine at a dose of 0.3 mg/100 g of body weight (daily within 1 week); 4 (second experimental group) - animals in which uridine was administered daily starting from day 4 (at the peak of pneumonia). Animals with EP were examined at 5th (n = 10), 9th (n = 8) and 12th (n = 6) days of the disease development, as well as 1 (n = 5) and 2 (n = 5) months after EP modeling. It was shown that in the first experimental group on the 5th day of EP development, an isoventilator restructuring of respiration was observed. In this group, from day 12 to the end of the study, there was a stenoventilator restructuring of breathing, which was characterized by an increase in tidal volume, alveolar ventilation, oxygen consumption and, accordingly, an increase in oxygen extraction from the alveoli and in the oxygen effect of the respiratory cycle. It can be assumed that in this group, an increase in the intensity of metabolism is provided by the effective activity of the respiratory system. In the second experimental group, isoventilator changes in respiration were observed with a gradual decrease in oxygen consumption and other indicators of the respiratory system efficiency. After 2 months, these changes became significant. Thus, we can talk about significant differences in the effect of uridine on the function of external respiration (i.e., apparently, on the activity of the mitochondrial ATP-dependent K+ channel) during EP, which depended on the period of onset of uridine administration. Application of uridine immediately (1st experimental group) looks more effective and even has a stimulating effect on the respiratory function over a long period of experiment. The administration of uridine starting from the 4 partially normalizes the respiration parameters. However, after 1 month there is a depression of the functions of the respiratory system, which, probably, may further worsen. The reasons for the differences in the identified dynamics require further investigation.

Impacts of Mixing Mode on Photocatalytic Reduction of Hexavalent Chromium over Titanium Dioxide Nanomaterial under Various Environmental Conditions

This study explores the effects of initial Cr(VI) concentration, wavelength, hole-scavenger (absence and presence of salicylic acid), and oxygen conditions (aeration by air, nitrogen gas, and mechanical stir only) on photocatalytic reduction of hexavalent chromium over titanium dioxide photocatalyst and the chromic species distribution after photocatalysis. The experimental results show the existence of strong interactions between these factors. The factor of hole-scavenger was more important than the UV light wavelength condition for a reduction of 3 mg Cr(VI) L−1, whereas both factors became important when Cr(VI) concentration increased to 20 mgL−1. The higher the UV wavelength was, the less the amount of chromium retained on the TiO2 surface. The influence of oxygen-containing conditions in the solution on the reduction of 3 mgL−1 Cr(VI) was unobvious, whereas its influence became remarkable for the reduction of 20 mgL−1 Cr(VI) in the presence of SA. The interaction between oxygen-containing factor and other environmental factors, such as Cr(VI) concentration and scavenger presence (SA in this study), is a key factor about the degree of oxygen effect on Cr(VI) photo-reduction and the chromic species distribution. Simple stirring obtained better photocatalytic efficiency than aeration by air or nitrogen gas.

Nitrous Oxide/Oxygen Effect on IANB Injection Pain and Mandibular Pulpal Anesthesia in Asymptomatic Subjects

The inferior alveolar nerve block (IANB) does not always result in successful pulpal anesthesia. Nitrous oxide may increase the success of the IANB. The purpose of this investigation was to study the effect of nitrous oxide/oxygen (N2O/O2) on IANB injection pain and mandibular pulpal anesthesia in asymptomatic subjects. One hundred five asymptomatic subjects received an IANB after the administration of N2O/O2 or room air/oxygen (air/O2) at 2 separate appointments. After the IANB, subjects rated their level of pain for each phase of the injection (needle insertion, needle placement, and solution deposition) using a Heft Parker visual analog scale. Pulpal anesthesia was evaluated with an electric pulp tester for 60 minutes. The mean pain rating for all 3 injection phases showed a statistically significant reduction in pain when N2O/O2 was used compared with Air/O2 (P < .05). Odds ratios demonstrated a statistically significant increase in IANB success for the N2O/O2 group compared with the air/O2 group. N2O/O2 administration statistically decreased pain for all 3 injection phases of the IANB. In addition, nitrous oxide statistically increased the likelihood of pulpal anesthesia for posterior mandibular teeth. However, the incidence of pulpal anesthesia was not 100%.

The Dissolved Oxygen Effect on the Controlled Growth of Filamentous Microorganisms in Membrane Bioreactors

Membrane fouling still remains a drawback for membrane bioreactors; there is nevertheless a natural promising solution which is the growth of filamentous microorganisms in moderate concentrations. In this project, an innovative 25 L membrane bioreactor is used, consisting of two aerated tanks and a membrane tank. The first tank is supplied with high Food/Microorganism (F/M) loading and the second tank with very low loading. The aerated tanks were constantly provided with dissolved oxygen (DO) 2.5 ± 0.5 mg/L. Finally, it is concluded that the imposed aeration conditions contribute to the growth and control of filaments in moderate concentrations having a filamentous index = 2 and therefore reducing membrane fouling for more than 1.5 months, maintaining the trans-membrane pressure at 1.4 ± 0.11 kPa.

Optimization of Dose Fractionation for Radiotherapy of a Solid Tumor with Account of Oxygen Effect and Proliferative Heterogeneity

A spatially-distributed continuous mathematical model of solid tumor growth and treatment by fractionated radiotherapy is presented. The model explicitly accounts for three time and space-dependent factors that influence the efficiency of radiotherapy fractionation schemes—tumor cell repopulation, reoxygenation and redistribution of proliferative states. A special algorithm is developed, aimed at finding the fractionation schemes that provide increased tumor cure probability under the constraints of maximum normal tissue damage and maximum fractional dose. The optimization procedure is performed for varied radiosensitivity of tumor cells under the values of model parameters, corresponding to different degrees of tumor malignancy. The resulting optimized schemes consist of two stages. The first stages are aimed to increase the radiosensitivity of the tumor cells, remaining after their end, sparing the caused normal tissue damage. This allows to increase the doses during the second stages and thus take advantage of the obtained increased radiosensitivity. Such method leads to significant expansions in the curative ranges of the values of tumor radiosensitivity parameters. Overall, the results of this study represent the theoretical proof of concept that non-uniform radiotherapy fractionation schemes may be considerably more effective that uniform ones, due to the time and space-dependent effects.