Optimization of Osthole in the Lactone Ring: Structural Elucidation, Pesticidal Activities, and Control Efficiency of Osthole Ester Derivatives

2021 ◽  
Author(s):  
Shaochen Li ◽  
Min Lv ◽  
Zhiqiang Sun ◽  
Meng Hao ◽  
Hui Xu
Keyword(s):  
Lactone Ring ◽  
Structural Elucidation ◽  
Control Efficiency ◽  
And Control

scholarly journals Effect of Unmanned Aerial Vehicle Flight Height on Droplet Distribution, Drift and Control of Cotton Aphids and Spider Mites

Agronomy ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 187 ◽  
Author(s):  
Zhaoxia Lou ◽  
Fang Xin ◽  
Xiaoqiang Han ◽  
Yubin Lan ◽  
Tianzhu Duan ◽  
...  
Keyword(s):  
High Speed ◽  
Plant Protection ◽  
Spider Mites ◽  
Coverage Rate ◽  
Cotton Leaf ◽  
Control Efficiency ◽  
Cotton Pests ◽  
Droplet Distribution ◽  
Flight Height ◽  
And Control

Unmanned aerial vehicles (UAVs), as emerging plant protection machinery, have the advantages of high operational efficiency, high speed, and low drift. The current study aimed to elucidate the characteristics of droplet distribution and drift, control efficiency on cotton aphids and spider mites, and attachment and absorption of cotton leaves during UAV spraying. Kromekote card and filter paper are used as samplers to collect droplets, and the droplet density, coverage rate, deposition, and drift percentage are statistically analyzed. The pooled results showed that the droplet uniformity, the droplet coverage rate, the deposition, and the drifting ability are higher when the UAV flight height was 2 m. The control effects by UAV spraying on cotton aphids and spider mites were 63.7% and 61.3%, respectively. These values are slightly inferior to those obtained through boom spraying. Cotton leaf attachment and absorption of spirodiclofen after UAV spraying were slightly lower than those after boom spraying, therefore, the control efficiency of cotton pests is slightly different. According to the different flight height operations by the UAV sprayer, the drift capability of the droplets at 2 m flight height was large, and the droplet uniformity and deposition were satisfactory. The research results could provide the theoretical basis and technical support for UAV operation.

scholarly journals Efficiency in Heating Operation of Low-Temperature Radiant Systems Working under Dynamic Conditions in Different Kinds of Buildings

2018 ◽  
Vol 8 (12) ◽  
pp. 2399 ◽  
Author(s):  
Giulia Alessio ◽  
Michele De Carli ◽  
Angelo Zarrella ◽  
Antonino Di Bella
Keyword(s):  
Heat Pump ◽  
Variable Temperature ◽  
Thermal Inertia ◽  
Energy Performance ◽  
Outdoor Temperature ◽  
Dynamic Conditions ◽  
Control Efficiency ◽  
Floor Systems ◽  
And Control ◽  
Better Than

In recent years many types of radiant systems have been installed in buildings. Meanwhile, practitioners debate on which thermal inertia of radiant systems fit better and which control strategies should be better in buildings, depending on the insulation level and thermal inertia of the structures. In particular, in new and retrofitted buildings, where the envelope presents high levels of insulation, it is argued if it is better to have low or high inertia radiant systems for controlling the indoor operative temperature and avoid overheating, especially in mid-seasons when the outdoor temperature is mild and solar radiation is high. For this purpose a room with three types of insulation level has been analysed combining different types of structures (masonry, and light and timber walls) and three types of radiant systems (classic wet floor, dry floor, and ceiling). Two operation modes have been simulated: fixed supply temperature and variable temperature according to the outdoor temperature. The results looked at the embedded and control efficiency, the energy performance in case of coupling with a water to water heat pump and the long-term possible overheating analysis. The embedded and control efficiency in dynamic conditions has been evaluated and compared with different possible definitions, in particular with steady state conditions, former EN15316-2-2007, and current EN15316-2-2017. New values for the current standard are suggested based on the results of this work, since the former and existing values overestimate the seasonal losses of floor and radiant systems in heating conditions. The paper shows that working at variable temperature according to the outdoor air temperature leads to longer operation time. The temperature, on average, lowers, and coupling the radiant system with a water to water heat pump leads to lower consumptions in the case of variable supply temperature compared to fixed supply temperature over the season. The seasonal coefficient of performance of the whole system, i.e. the heat pump and auxiliary pumps, leads to overall lower energy consumption in the case of variable supply temperature. The simulations did not show any relevant problem of discomfort from December to February. Overtemperature effects in terms of operative temperatures over the dead band of the control systems are not especially due to the radiant system, but they also occur in any case with ideal convective systems. The paper demonstrates that in general the radiant floor systems perform better than radiant ceilings in heating conditions and there is no evidence that dry floor systems perform better than wet screed systems in all the types of buildings regardless of the level of insulation and thermal inertia.

Construction of oxime ester derivatives of osthole from Cnidium monnieri , and evaluation of their agricultural activities and control efficiency

2020 ◽  
Vol 76 (11) ◽  
pp. 3560-3567
Author(s):  
Zili Ren ◽  
Min Lv ◽  
Tianze Li ◽  
Meng Hao ◽  
Shaochen Li ◽  
...  
Keyword(s):  
Agricultural Activities ◽  
Control Efficiency ◽  
And Control ◽  
Derivatives Of

scholarly journals Modeling analysis reveals the transmission trend of COVID-19 and control efficiency of human intervention

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Chaoyuan Cheng ◽  
Xinru Wan ◽  
Zhibin Zhang
Keyword(s):  
Early Stage ◽  
Close Contact ◽  
Control Measures ◽  
Republic Of Korea ◽  
Logistic Growth ◽  
Human Intervention ◽  
Control Efficiency ◽  
Transmission Parameters ◽  
Increase Rate ◽  
And Control

Abstract Background A novel coronavirus disease (COVID-19) has caused huge damage to public health around the world. Revealing the transmission dynamics of COVID-19 and control efficiency is important for containing the spread of the virus. Methods By using a logistic growth model, we estimated the transmission parameters of COVID-19 in China and six other countries (Republic of Korea, Iran, Italy, Spain, France and Germany). The transmission parameters represent the maximum daily increase rate in the early stages of the epidemic and the control efficiency under human intervention. The control efficiency was determined by the significant decrease of the daily increase rate in time and cumulative cases. Results We found the daily increase rate of cumulative cases of COVID-19 decreased significantly in both time and cumulative cases in all countries, but the decreasing trend was not further reduced in other countries except for China and Republic of Korea. The response of the daily increase rate to control measures was much earlier than the number of new cases. Conclusions Our results suggested that lockdown at the epicenter and social distancing effectively reduced the spread of COVID-19 in the early stage, but identification and isolation of patients, suspected cases and people with close contact at a community level is essential in further reduction of the daily increase rate of COVID-19.

scholarly journals Formulations and evaluation of Cyclodextrin complexed Ceadroxil loaded nanosponges

2017 ◽  
Vol 9 (3) ◽  
pp. 84 ◽  
Author(s):  
Pawan Dubey ◽  
Hemant Kumar Sharma ◽  
Sunil Shah ◽  
Chandra Kishore Tyagi ◽  
Amol R. Chandekar ◽  
...  
Keyword(s):  
Lactone Ring ◽  
Release Kinetics ◽  
Major Drawback ◽  
Zeta Potentials ◽  
Poorly Soluble ◽  
Dosing Intervals ◽  
And Control ◽  
Kinetics Of ◽  
Derivatives Of

<p>Cefadroxil (CFD) is a broad spectrum antibiotic that acts against an extensive variety of bacteria, including Gram-positive and Gram-negative bacteria. The major drawback of orally administered drug like cefadroxil is its shorter half life of 1.2 hrs. The goal of the study is to prolong the drug release, producing a desired blood serum level, reduction in drug toxicity and improving the patient compliance by prolonging the dosing intervals. Cyclodextrin-based nanosponges (NS) are a novel class of cross-linked derivatives of cyclodextrins. They have been used to increase the solubility of poorly soluble actives, to protect the labile groups and control the release. This study aimed at formulating complexes of CFDwith three types of β-cyclodextrin NS obtained with different cross-linking ratio (viz. 1:2, 1:4 and 1:8 on molar basis with the cross-linker) to protect the lactone ring from hydrolysis and to prolong the release kinetics of CFD. Crystalline (F<sub>1:2</sub>, F<sub>1:4</sub> and F<sub>1:8</sub>) and paracrystalline NS formulations were prepared. XRPD, DSC and FTIR studies confirmed the interactions of CFDwith NS. XRPD showed that the crystallinity of CFD decreased after loading. CFD was loaded as much as 21%, 37% and 13% w/w in F<sub>1:2 </sub>, F<sub>1:4</sub> and F<sub>1:8</sub>, respectively while the paracrystalline NS formulations gave a loading of about 10% w/w or lower. The particle sizes of the loaded NS formulations were between 450 and 600 nm with low polydispersity indices. The zeta potentials were sufficiently high (-20 to -25 mV) to obtain a stable colloidal nanosuspension. The in vitro studies indicated a slow and prolonged CFD release over a period of 24 h. The NS formulations protected the lactone ring of CFD after their incubation in physiological conditions at 37°C for 24 h with a 80% w/w of intact lactone ring when compared to only around 20% w/w of plain CFD.</p>

A Differential Configuration of Split Drag-Rudders with Variable Bias for Directional Control of Flying-Wing

2014 ◽  
Vol 643 ◽  
pp. 54-59 ◽  
Author(s):  
Jahanzeb Rajput ◽  
Wei Guo Zhang ◽  
Xiao Bo Qu
Keyword(s):  
Cfd Simulation ◽  
Angle Of Attack ◽  
Large Angle ◽  
Simple Method ◽  
Low Speed ◽  
Control Efficiency ◽  
Stability And Control ◽  
Directional Stability ◽  
Variable Bias ◽  
And Control

The directional stability and control is crucial for the low-speed flight of a flying-wing aircraft. The split drag-rudders are well known devices used to provide directional stability and control in a flying-wing aircraft. As opposed to conventional rudders, the control efficiency of split drag-rudders is typically low for small deflection-angles and the influence on yawing moment is nonlinear. Such characteristics limit the control capability of split drag-rudders at low speed flight with large angle-of-attack. In this paper, a simple method is presented to improve the control efficiency of split drag-rudders at low speed flight with large angle-of-attack. The method is based on a strictly differential configuration of split drag-rudders which operates around a certain variable bias. The bias can be varied according to different flight conditions in order to achieve desired performance. The CFD simulation results are presented in support of this concept. Results also show that the proposed configuration has linearizing effects on yawing moment vs. deflection curves, which may prove helpful in control system design process. The possible control reversal in yaw at large angle of attack can also be avoided with this method.

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