Activation of Cobalt Foil Catalysts for CO Hydrogenation

CO hydrogenation has been studied on cobalt foils as model catalysts for Fischer–Tropsch (FT) synthesis. The effect of pretreatment (number of calcinations and different reduction times) for cobalt foil catalysts at 220 °C, 1 bar, and H2/CO = 3 has been studied in a microreactor. The foils were examined by scanning electron microscopy (SEM). It was found that the catalytic activity of the cobalt foil increases with the number of pretreatments. The mechanism is likely an increase in the available cobalt surface area from progressively deeper oxidation of the foil, supported by surface roughness detected by SEM. The highest FT activity was obtained using a reduction time of only 5 min (compared to 1 and 30 min). Prolonged reduction caused the sintering of cobalt crystallites, while too short of a reduction time led to incomplete reduction and small crystallites susceptible to low turn-over frequency from structure sensitivity. Larger crystals from longer reduction times gave increased selectivity to heavier components. The paraffin/olefin ratio increased with the increasing number of pretreatments due to olefin hydrogenation favored by enhanced cobalt site density. From the results, it is suggested that olefin hydrogenation is not structure sensitive, and that mass transfer limitations may occur depending on the pretreatment procedure. Produced water did not influence the results for the low conversions experienced in the present study (<6%).

Degradation detection for internal gear pumps using pressure reduction time maps

In this paper, a novel approach for detecting degradation in internal gear pumps is proposed. In a data-driven approach, pressure reduction time maps (PRTMs) are identified as a useful indicator for degradation detection. A PRTM measures the time for reducing the internal pump pressure from certain levels to any lower level when the pump engine is stopped and the valves are closed. The PRTM can thus be interpreted as an internal leakage indicator of the pump. For simplified evaluation, PRTMs are compressed to a single scalar indicator by computing their volume (PRTMV). When the internal leakage increases due to wear, the pressure in the pump decreases faster (implying a decreased PRTMV). The proposed approach has been developed and tested with data of real internal gear pumps with different operating times. The PRTMV shows a close relation to the operating time of the pump. Moreover, we compare PRTMV with the commonly used and well known approach of observing pressure holding speed (PHS). Especially for medium degradation, PRTMV shows better sensitivity then PHS.

On the dynamics of gravity-induced wave function reduction

In this study, we use the concept of Bohmian trajectories to present a dynamical and deterministic interpretation for the gravity-induced wave function reduction. We shall classify all possible regimes for the motion of a particle, based on the behavior of trajectories in the ensemble and under the influence of quantum and gravitational forces. In the usual approaches all the information is obtained from the wave function evolution. But, on the basis of Bohm’s deterministic quantum theory, we can investigate the motion of the particle during the reduction processes. This leads to analytical and numerical results for the reduction time and equation of motion of the particle. In this regard, a new visualization will be provided for the reduction time.

Application Experience of Moist Wound Healing Theory Combined with Modern New Dressings in the Treatment of Pressure Ulcers

Objective?Research on the effect of moist wound healing theory in a combination with modern new dressingtreatment in patients diagnosed with pressure ulcers. Method: Selected 30 patients with pressure ulcers from our hospital, which is Shandong Tai’an Municipal Hospital, from January 2019 to January 2021 were divided into experimental group (15 cases, treated with moist wound healing theory combined with modern new dressings) and control group (15 cases, applied conventional treatments). The treatment effect, time of wound edema subsidence, wound healing time, number of dressing changes, granulation tissue growth time, and diameter reduction time were compared between the two groups. Results: The total effective rate of the experimental group (93.33%, 14/15) was higher than that of the control group (53.33%, 8/15), P<0.05; the time to subsidence of wound edema in the experimental group was (3.11±0.22), and the time for wound healing was (12.78±0.45), the number of dressing changes (7.13±0.34) times, the growth time of granulation tissue (5.43±2.22), the diameter reduction time (6.25±3.75), compared with the control group, P<0.05. Conclusion?In the clinical treatment of patients diagnosed with pressure ulcers, the effective combination of moist healing theory and modern new dressing therapy has significant effects, whereby it speeds up the healing process of the pressure ulcers, and it is proven to be worthy to be promoted for usage.

Effect of magnesium reduction on the oxygen content of pickling niobium powder

Considering the problem of high oxygen content in industrial niobium powder, the oxygen reduction of high oxygen niobium powder with the addition of magnesium is studied. Based on the thermodynamic analysis of magnesium thermal reduction of niobium powder, the effects of reduction temperature, magnesium addition, reduction time, and reduction atmosphere on the oxygen content of pickling niobium powder are studied. The results show that with an increase in the magnesium addition, the oxygen content of pickling niobium powder gradually decreases to a certain value, and then remains unchanged. In a certain temperature range (953–1203 K), with an increase in the reduction temperature, the oxygen content of pickling niobium powder first decreases, and then increases; the best oxygen content is 356 ppm at 1133 K. With the extension in reduction time (2–6 h), the oxygen content of pickling niobium powder first decreases, and then remains unchanged. Finally, the oxygen content of pickled niobium powder is reduced to approximately 356 ppm at 400% magnesium addition at 1133 K for 4 h.

Fungicidal Activity of Five Disinfectants on Isolates of Candida Species

Determine fungicidal activity of five disinfectants on Candida auris of clinical and environmental origin. Assess fungicidal efficiency of each disinfectants on the microorganism. Calculate percentage of efficiency (% E) of each disinfectants on Candida strain and determine specific death rate (k) and decimal reduction time for the microorganism. An analytic and experimental research with quantitative methods. We realized a strains workbench by culturing it in corresponding culture media. Analysis was a challenge essay, performed on four surfaces and at different exposure times; 1, 5, 15 and 30 minutes of contact between disinfectant and yeast. Once disinfection process was carried out, what was expected was that after 15 minutes of contact between the yeasts and the disinfectants, a percentage of inhibition of the microorganism between 90 and 95% was presented, thus guaranteeing the duration of elimination of the infectious agent by disinfectants. Results shows that after one minute of contact between Candida auris and the disinfectant in a gloved hand, there was a removal of the yeast, when the clinical and environmental strain were analyzed. Data showing disinfectants efficiency percentages greater than 90% over strains of Candida used in the study. Decimal reduction times in seconds of the strains of Candida against the disinfectants used in the study were between 9.3 and 14.04 s. It was possible to evaluate effectiveness by means inhibition percentage of each disinfectants on the strains of Candida auris of clinical and environmental origin. Similarly, specific death rate and decimal reduction time in seconds were determined for strains under study.

Effect of Coated Cow Dung on Fluidization Reduction of Fine Iron Ore particles

The effects of reduction temperature, gas linear velocity, reduction pressure, reduction time, and reducing gas on the fluidized ironmaking process were studied for the fine iron Newman ore particles (0.154–0.178 mm) and the optimal experimental operating conditions were obtained. Under the optimal conditions, the effects of the coated cow dung on the reduction of fine iron ore particles were studied, and the inhibition mechanism of cow dung on particle adhesion in the fluidized ironmaking process was elucidated. The experimental results show that the optimal operating parameters are linear velocity of 0.6 m/s, reduction pressure of 0.2 MPa, reduction temperature of 1023 K, H2 as the reducing gas, and reduction time of 60 min. Cow dung can react with oxide in the ore powder to form a high melting point substance that can form a certain isolation layer, inhibit the growth of iron whiskers, and improve the fluidization.

Improved Catalytic Activity of the High-Temperature Water Gas Shift Reaction on Metal-Exsolved La0.9Ni0.05Fe0.95O3 by Controlling Reduction Time

The catalyst exsolved from nickel-doped perovskite oxide, La0.9Ni0.05Fe0.95O3, has been proven to be effective for gas-phase reactions. To obtain the optimum amount of exsolved nanoparticles from the parent perovskite oxide, control of the reduction treatment condition is vital. Here, the effect of reduction time on the exsolved nanoparticle distribution, and thus the catalytic activity of the high-temperature water gas shift reaction (WGSR), was investigated. Upon conducting a wide range of characterizations, we assumed that the exsolution process might be a two-step process. Firstly, the surface oxygen is extracted. Secondly, due to the unstable perovskite structure, the Ni ions in the bulk La0.9Ni0.05Fe0.95O3 continuously diffuse toward the surface and, as the reduction progresses, more nuclei are generated to form a greater number of nanoparticles. This assumption is proven by the fact that, with an increase in the exsolution treatment time, the population of exsolution nanoparticles increases. Moreover, as the reduction time increases, the high-temperature WGSR activity also increases. The temperature-programmed measurements suggest that the exsolved nanoparticles are the active reaction sites. We believe that this study is helpful for understanding exsolution behavior during reduction treatment and, thus, developing a perovskite exsolution catalyst for the WGSR.