Adaptive backstepping control for ship nonlinear active fin system based on disturbance observer and neural network

<span>Adaptive backstepping control based on disturbance observer and neural network for ship nonlinear active fin system is proposed. One disturbance observer is given to observe the disturbances of the system, by this way, the response time is shorten and the negative impact of disturbance and uncertain elements of the system is reduced. In addition, radial basic function neural network (RBFNN) is proposed to approach the unknown elements in the ship nonlinear active fin system, therefor the system can obtain good roll reduction effectiveness and overcome the uncertainties of the model, the designed controller can maintain the ship roll angle at desired value. Finally, the simulation results are given for a supply vessel to verify the successfulness of the proposed controller.</span>

Waning of SARS-CoV-2 booster viral-load reduction effectiveness

The BNT162b2 COVID-19 vaccine has been shown to reduce viral load of breakthrough infections (BTIs), an important factor affecting infectiousness. This viral-load protective effect has been waning with time post the second vaccine and later restored with a booster shot. It is currently unclear though for how long this regained effectiveness lasts. Analyzing Ct values of SARS-CoV-2 qRT-PCR tests of over 22,000 infections during a Delta-variant-dominant period in Israel, we found that this viral-load reduction effectiveness significantly declines within months post the booster dose. Adjusting for age, sex and calendric date, Ct values of RdRp gene initially increased by 2.7 [CI: 2.3-3.0] relative to unvaccinated in the first month post the booster dose, yet then decayed to a difference of 1.3 [CI: 0.7-1.9] in the second month and became small and insignificant in the third to fourth months. The rate and magnitude of this post-booster decline in viral-load reduction effectiveness mirror those observed post the second vaccine. These results suggest rapid waning of the booster's effectiveness in reducing infectiousness, possibly affecting community-level spread of the virus.

Reduction of River Pollutants with Raffia-Cord in Sail River Pekanbaru Indonesia

The Sail River has been polluted by various types of pollutants in Pekanbaru. Raffia-cord is shaped like a feather duster, made of raffia rope that has been smoothed and then woven like a feather duster. This research was conducted as an effort to reduce the river pollutants (nitrate, phosphate, ammonia, Pb, Cr, COD, and BOD5. The study was carried out in Sail River in March – April 2019 using the Completely Randomized Design (CRD) method with density variations: low density (P1), medium density (P2), and high density (P3). The average results showed that the decrease for nitrate was 0.075-0.117 mg/L (35-44%) from 0.136-0.347 mg/L; phosphate 0.205-0.267 mg/L (29-40%) from 0.339-0.381 mg/L; ammonia 0.027-0.076 mg/L (28-58%) from 0.093-0.108 mg/L. The decreasing effectiveness of P1, P2, and P3 for Pb were 67.146%, 70.465% and 67.242%; for Cr were 81.346%, 83.335% and 81.893%. The average COD reduction effectiveness were 38.7%; 46.9%; 42.5% while BOD5 were 71.4%, 74.1% and 69.5%. It was concluded that raffia-cord could be used to reducing nitrate, phosphate, and ammonia levels, raffia-cord was able to reduce the concentration of Pb and Cr but raffia-cord had no significant effect on decreasing COD and BOD5.

Pilot-Scale Experimental Study on Impacts of Biomass Cofiring Methods to NOx Emission from Pulverized Coal Boilers—Part 2: NOx Reduction Capability through Reburning versus Cofiring

In this study the NOx reduction capability of reburning three biomasses (i.e., wood pellet, torrefied biomass, and empty fruit bunch) via 12 cases (i.e., four reburning ratios for every biomass) is investigated in a 1 MWth-scale pilot-scale furnace. These reburning cases are compared with 12 cofiring cases presented in the Part 1 paper on a consistent basis. It is found that, for every cost to purchase and prepare biomass, reburning technology provides significantly better NOx abatement performance than cofiring (up to 3.4 times). NOx reduction effectiveness as high as 4.9 could be achieved by reburning, which means the percent of NOx abatement could be 4.9 times higher than the percent of reburning ratio. It is found that the highest NOx reduction per thermal unit of biomass happens at the lowest reburning ratio, and increasing the reburning ratio leads to a reduction in NOx abatement effectiveness in an exponential decay manner. Unlike cofiring technology, reburning was found to have little dependence on the fuel characteristics, such as fuel ratio or fuel-N, when it comes to NOx abatement potential.

Real-world cost-effectiveness of denosumab for the treatment of postmenopausal osteoporosis in Taiwan

Summary This study assessed the cost-effectiveness of continued denosumab treatment, compared with discontinuation of denosumab after one dose, for the treatment of postmenopausal osteoporosis in Taiwan, using real-world fracture reduction effectiveness and cost data. Outcomes indicate that continued denosumab treatment produces an incremental cost-effectiveness ratio of USD $16,743 per QALY. Purpose To evaluate the cost-effectiveness of continued denosumab use versus discontinuation after one dose, for the treatment of postmenopausal osteoporosis in Taiwan, using real-world fracture reduction effectiveness and cost data. Methods A Markov cohort model was used to evaluate the lifetime costs and QALYs associated with continued denosumab treatment versus discontinuation of treatment after one dose. The evaluation was conducted from the perspective of Taiwan’s healthcare system and used a discount rate of 3% per annum. The patient population consisted of postmenopausal women with osteoporosis with a mean age of 77 years who initiated denosumab treatment. Fracture reduction effectiveness data, baseline fracture rates, mortality data, and costs of fracture were informed by Taiwan’s National Health Insurance Research Database. Results Model outcomes showed that continued treatment with denosumab produced an expected gain of 0.042 QALYs and an incremental cost of USD $704, compared with discontinuation of denosumab after one dose. This corresponds to an incremental cost-effectiveness ratio of USD $16,743 per QALY gained. Probabilistic and scenario analysis showed that results are stable to variations in model assumptions and parameters. Conclusion In a real-world setting, at a cost per QALY threshold equivalent to gross domestic product per capita in 2020 in Taiwan (USD $30,038), continued treatment with denosumab in postmenopausal women with osteoporosis is cost-effective compared with treatment discontinuation.