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Li, Zi Cheng, Ai Ju Zhang, Zhong Qiu Li, and Hui Qiang Xiang. "Synthesis of Compound Foaming Agent of Lightweight Foamed Concrete." Advanced Materials Research 785-786 (September 2013): 163–66. http://dx.doi.org/10.4028/www.scientific.net/amr.785-786.163.
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The foaming agent used in lightweight gypsum-based foam concrete was discussed. The effect of the single-doped foaming agent, codoped foaming agent and ternary foaming agent on the settling height, bleeding volume and defoaming time of fresh foam were investigated. The results show that ternary foaming agent has potential synergistic effects for reducing settling height and bleeding volume and retarding defoaming time of fresh foam. While applying this new compound foaming agent to the manufacture of the lightweight foam concrete blocks, samples with better-performance were obtained.
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Thanikachalam, J., P. Nagaraj, and G. S. Hikku. "Effect of graphene as anti-settling agent for magnetorheological fluid." Journal of Achievements of Materials and Manufacturing Engineering 77, no. 2 (2016): 49–56. http://dx.doi.org/10.5604/17348412.1230097.
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Chai, Xiaofeng, Jian Liu, Yao Yu, Jianxiang Xi, and Changyin Sun. "Practical Fixed-Time Event-Triggered Time-Varying Formation Tracking Control for Disturbed Multi-Agent Systems with Continuous Communication Free." Unmanned Systems 09, no. 01 (2020): 23–34. http://dx.doi.org/10.1142/s2301385021500035.
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In this paper, we study the practical fixed-time event-triggered time-varying formation tracking problem of leader-follower multi-agent systems with multi-dimensional dynamics. Fixed-time event-triggered control schemes with continuous communication and intermittent communication are developed, respectively. Continuous communication and measurement are avoided, and computation cost is reduced greatly in the latter scheme. And the settling time is to be specified regardless of initial states of agents. Meanwhile, tracking errors are adjustable as desired with expected settling time. It is demonstrated that time-varying formation tracking can be achieved under the two proposed control schemes and Zeno behavior can be excluded. Finally, numerical examples are provided to illustrate the effectiveness of the proposed control strategies.
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Kirjanova, Ala, Mindaugas Rimeika, Jes Vollertsen, and Asbjørn Haaning Nielsen. "Retainment of the antimicrobial agent triclosan in a septic tank." Water Science and Technology 70, no. 4 (2014): 586–92. http://dx.doi.org/10.2166/wst.2014.271.
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Laboratory experiments were conducted to investigate the fate of the antimicrobial agent triclosan (TCS) in a conventional septic tank. The main mechanism of TCS removal from wastewater was identified to be rapid TCS sorption to suspended particles followed by settling of these particles to the bottom of the septic tank. Sorption to particles was completed within minutes while the settling took several days. Therefore, in a septic tank the removal of TCS from wastewater is mainly determined by the removal of suspended particles by sedimentation. Over 5 days of hydraulic residence time the initial dissolved TCS concentration of 100 μg L−1 was reduced by 87 ± 8%. During the first 24 hours, 66–86% of all removed TCS was retained, whereas during the remainder of the experiment a slight but steady decrease in TCS concentration was observed. This was most likely caused by TCS diffusion and its subsequent sorption onto the septic sludge.
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Schuck, Peter H. "The Role of Judges in Settling Complex Cases: The Agent Orange Example." University of Chicago Law Review 53, no. 2 (1986): 337. http://dx.doi.org/10.2307/1599643.
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Naiguo, Wang, Nie Wen, Cheng Weimin, Liu Yanghao, Zhu Liang, and Zhang Lei. "Experiment and Research of Chemical De-dusting Agent with Spraying Dust-settling." Procedia Engineering 84 (2014): 764–69. http://dx.doi.org/10.1016/j.proeng.2014.10.494.
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Shi, Shao Fei, Lan Zheng, Yu Qi Wang, et al. "Preparation and Application Study on the Coalmine Wastewater Flocculant - PAM/OMMT." Advanced Materials Research 581-582 (October 2012): 223–27. http://dx.doi.org/10.4028/www.scientific.net/amr.581-582.223.
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The modified polyacrylamide/organic montmorillonite (PAM/OMMT) flocculant was prepared by in-situ intercalation polymerization with acrylamide monomer and OMMT under CO2 inert atmosphere. The OMMT was synthesized with MMT and cetyl trimethyl ammonium bromide (CTAB) as intercalation agent by cationic exchange reaction. This flocculant was used to deal with coalmine wastewater. The effects of the flocculant dose on turbidity removal rate and settling time, the influent of pH value, temperature on turbidity removal rate and the comparison with PAM was studied. Experimental results show that PAM/OMMT is a kind of high efficient compound flocculating agent, the formation of hydrophobic micro in polymer surface area has strong adsorption ability and dispersing capability. Then MMT increased the quality of flocculant body so that flocculating settling time is shorter. Its turbidity removal rate can be as high as 95.5%. Compared with PAM, PAM/OMMT presents many advantages with higher turbidity removal rate, higher settling velocity, lower relatively sludge water content and lower sensitivity of temperature and pH in wastewater treatment process. Flocculant dosage in 10 to 20 mg/L is the optimal flocculation condition. Sludge water content treated by PAM/OMMT (63.4%) is relatively lower than PAM (80.2%).
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Yin, Yanhui, Fuyong Wang, Zhongxin Liu, and Zengqiang Chen. "Finite/fixed-time consensus of nonlinear multi-agent systems against actuator faults and disturbances." Transactions of the Institute of Measurement and Control 42, no. 16 (2020): 3254–66. http://dx.doi.org/10.1177/0142331220949354.
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This paper is concerned with the consensus tracking problem in nonlinear multi-agent systems against external disturbances and multiple actuator faults. The nonlinear dynamics are unknown and the leader’s input is unavailable to any follower. By using finite-time Lyapunov stability theory, a distributed discontinuous protocol is developed. On this basis, a fixed-time control protocol is further designed to obtain a settling time regardless of initial conditions. In addition, the practical finite-time consensus and practical fixed-time consensus are investigated by the adaptive technique, under which the bounds of the faults can be estimated online adaptively. The innovation of this work lies in the fact that the finite/fixed-time consensus problem is solved when multiple faults and mismatched nonlinearity are simultaneously considered. The relationship between the settling time and design parameters is well established. Finally, some numerical simulations are given to verify the effectiveness of the theoretical results.
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Ray, Martin. "Conrad, Wells, and "The Secret Agent": Paying Old Debts and Settling Old Scores." Modern Language Review 81, no. 3 (1986): 560. http://dx.doi.org/10.2307/3729180.
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Wu, Zhong Yuan, Liang Hu, and Jia Xi Chen. "Surface Hydrophobic Modification of T-ZnOw with Silane Coupling Agent." Advanced Materials Research 634-638 (January 2013): 3048–51. http://dx.doi.org/10.4028/www.scientific.net/amr.634-638.3048.
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Surface hydrophobic modification of T-ZnOw was experimented with silane coupling agent KH-570(gamma-(methylpropyl acyloxy)trimethoxysilane). It was shown by FT-IR that the whiskers was modified by silane coupling agents molecular compounded with the Zn-OH of whiskers. The effect of grafted modification with KH570 on hydrophobicity of T-ZnOw was characterized with dispersion stability test in an organic solvent and measuring the contact angle between the whiskers on distilled water. The results showed that surface treatment of T-ZnOw with KH570 improves hydrophobicity of whiskers simultaneously, and the modified whiskers have much slower settling rates than the pristine whiskers in the liquid paraffin. The contact angle between the modified whiskers with distilled water is 137.75 degrees, which is a significant increase.
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SCHACKOW, A., A. K. FERRARI, C. EFFTING, V. O. ALVES, and I. R. GOMES. "Stabilized mortar with air incorporator agent and plasticizer set retarder: performance measurement." Revista IBRACON de Estruturas e Materiais 12, no. 6 (2019): 1248–59. http://dx.doi.org/10.1590/s1983-41952019000600002.
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Abstract This study aims to develop three stabilized mortars to masonry using air entraining agents and settling retardant plasticizer to compare with a conventional mortar with lime. It was analyzed consistency index, specific gravity, air entrained content, water retentivity, setting time through the heat of hydration, mortar shrinkage/expansion, compressive strength, resistance to sulphate and tensile strength in bonding. The results exhibited that the presence of the settling retardant plasticizer affected the consistency index making the mortar more workable for a longer time. The presence of additives made the stabilized mortars lighter with lower mass density and higher incorporated air content. The presence of lime provided high water retentivity in the conventional mortar while the setting retardant plasticizer improved the water retentivity in the stabilized mortars. The initial setting time of the stabilized mortars occurred after approximately 50 hours. Conventional mortar lost its workability quickly after 2 hours. In conventional mortar, shrinkage occurred, while stabilized mortars had expansion. The conventional mortar exhibited better compressive strength, while the excess of additives can affected negatively this property in the stabilized mortars. Conventional mortar proved to be less resistant to sulphate attack. Tensile strength in bonding was better in a stabilized commercial mortar tested.
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Yan, Tingruo, Xu Xu, Zongying Li, and Eric Li. "Fixed-time leader-following flocking and collision avoidance of multi-agent systems with unknown dynamics." Transactions of the Institute of Measurement and Control 43, no. 12 (2021): 2734–41. http://dx.doi.org/10.1177/01423312211005277.
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The fixed-time flocking of multi-agent systems with a virtual leader is investigated in this paper. The motion dynamics of the agents are assumed to be unknown and only satisfy the boundedness, which does not need to be modelled by the Lipschitz condition. To achieve the flocking and collision avoidance for all agents in the fixed time, a control protocol in the high-dimensional space is developed by using the graph theory and the theoretical properties of differential equations. Moreover, the upper bound of the settling time only depending on the control protocol and the topology of network is estimated. Numerical examples are used to verify the theoretical results, and show that the proposed method provides an applicable method for the control of the nonlinear dynamic systems.
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Woodward, Jason E., Sara K. Gremillion, Jason H. Brock, Robert C. Kemerait, David B. Langston, and Jean L. Williams-Woodward. "Lilium lancifolium is Discovered as a New Host of Botryosphaeria parva in Georgia." Plant Health Progress 7, no. 1 (2006): 48. http://dx.doi.org/10.1094/php-2006-1127-02-br.
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A new disease on tiger lily (Lilium lancifolium Thunb.) was discovered in a residential settling in Georgia. Koch's postulate and molecular techniques confirmed that Botryosphaeria parva was the causal agent. This is the first report of B. parva on tiger lily. Accepted for publication 8 September 2006. Published 27 November 2006.
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Sun, Dong Yang, Xing Long Zhou, Wen Bin Luo, Zheng Qiang Liu, Zhi Xin Shi, and Xiao Ming Zhang. "Study on the Settlement Experiment of Iron Tailings." Applied Mechanics and Materials 281 (January 2013): 511–16. http://dx.doi.org/10.4028/www.scientific.net/amm.281.511.
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The settlement experiment of representative iron tailings was studied, the iron tailings were from a processing plant of Wuhan Iron and Steel Group. There were four experiments were conducted which includes nature sedimentation test, coagulation sedimentation test of inorganic salt coagulant, flocculation sedimentation test of polymer flocculant and the mix coagulation sedimentation test. The test results showed that the size of sample is relatively fine and unevenly distributed, what's more, the velocity of natural sediment is very slow, and the effect that concentration has on the settling velocity of particles is obvious. The inorganic salt coagulant could reduce turbidity of supernatant, but it play a limited role in improving settling rate, it was found that FeCl3 is the best coagulation agent, PAM is effective flocculant for the sample, and the coagulation effect of cationic flocculation (molecular weight is six million) is better than that of anionic and nonionic. The settling velocity of particles was improved and the solid content of supernatant was reduced in the mix coagulation sedimentation test, but the improvement of settling velocity was not obvious. The author suggests that the single cationic polyacrylamide flocculant which was used for pretreatment on the tailings could meet the requirement of the tailings settlement.
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Gruber, Stefanie, and Johann Plank. "Preparation and effectiveness of a high-temperature anti-settling agent for well cement slurries." Journal of Natural Gas Science and Engineering 81 (September 2020): 103416. http://dx.doi.org/10.1016/j.jngse.2020.103416.
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Pourjavadi, Ali, Seyed Mahmoud Fakoorpoor, and Seyed Hassan Hosseini. "Novel cationic-modified salep as an efficient flocculating agent for settling of cement slurries." Carbohydrate Polymers 93, no. 2 (2013): 506–11. http://dx.doi.org/10.1016/j.carbpol.2012.12.049.
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Fingas, Mervin F., Robert Stoodley, Nanci Stone, Russel Hollins, and Ian Bier. "Testing the Effectiveness of Spill-Treating Agents: Laboratory Test Development and Initial Results." International Oil Spill Conference Proceedings 1991, no. 1 (1991): 411–14. http://dx.doi.org/10.7901/2169-3358-1991-1-411.
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ABSTRACT Laboratory effectiveness tests have been developed for four classes of spill treating agents: solidifiers, demulsifying agents, surface-washing agents, and dispersants. Many of the currently available treating agents in these four categories have been tested for effectiveness. These results are presented. Solidifiers or gelling agents change liquid oil to a solid. Tests show that these require a large amount of agent to solidify oil, ranging from 16 percent by weight to over 200 percent. Demoussifiers or emulsion breakers are used to prevent or reverse the formation of water-in-oil emulsions. A newly developed effectiveness test shows that only one product is highly effective. However, many products will work, but require large amounts of spill treating agent. Surfactant-containing materials are of two types, surface-washing agents and dispersants. Testing has shown that an agent that is a good dispersant is conversely a poor surface-washing agent, and vice versa. Tests of surface washing agents show that only a few agents have effectiveness of 25 to 40 percent, where this effectiveness is defined as the percentage of oil removed from a test surface. Extensive work has been done on dispersant testing and comparison of laboratory tests. All laboratory tests will yield the same effectiveness value if the oil-to-water ratio is about 1:1,000 or greater, and if a settling time of 10 or more minutes is employed. Extensive results using the “swirling flask” testare reported. Heavy oils show effectiveness values of about 1 percent, medium crudes of about 10 percent, light crude oils of about 30 percent, and very light oils of about 90 percent.
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Zhou, Ding, An Zhang, and Pan Yang. "Fixed-time Output Feedback Consensus of Second-order Multi-agent Systems with Settling Time Estimation." International Journal of Control, Automation and Systems 18, no. 8 (2020): 2061–74. http://dx.doi.org/10.1007/s12555-019-0384-y.
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He, Xiaoyan, Yuqing Hao, and Qingyun Wang. "Leaderless finite-time consensus for second-order Lipschitz nonlinear multi-agent systems with settling time estimation." Physica A: Statistical Mechanics and its Applications 514 (January 2019): 280–89. http://dx.doi.org/10.1016/j.physa.2018.09.084.
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Pak, D., and W. Chang. "Color and suspended solid removal with a novel coagulation technology." Water Supply 2, no. 5-6 (2002): 77–81. http://dx.doi.org/10.2166/ws.2002.0153.
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A novel coagulation technology using atomized molten slag with ferrous sulfate has been developed to treat a turbid and colored water or wastewater. The atomized molten slag is produced by atomizing the molten slag from the steel-making process. The atomized molten slag has magnetic iron oxide in its constituent molecules so that it is magnetized. In this novel coagulation technology, the atomized molten slag acts as nuclei for coagulation process and weighting agent for the resultant floc. In this study, this new coagulation technology was compared with metal hydroxide flocs such as FeCl3 and PAC in treating textile wastewater. A batch settling test was conducted to investigate the settling characteristic of sludge formed with the atomized molten slag. The settling velocity of sludge formed with the atomized molten slag is almost ten times greater than that of sludge formed with FeCl3 or PAC. The coagulation using the atomized molten slag showed a higher removal rate of color, suspended solid, TOC, COD, TKN and T-P. The atomized molten slag is capable of adsorbing organic substance, ammonia and phosphate. This characteristic leads to higher removal rate than FeCl3 or PAC. The gel permeation chromatography of the wastewater treated using the atomized molten slag illustrated that this novel coagulation technology is more efficient in removing the particles with low molecular weight. The removal rates of color, suspended solid, COD, TOC, ammonia and phosphorous increase with increasing amount of atomized molten slag addition. Even though the atomized molten slag was overdosed, restabilization of particles was not encountered.
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Kofinas, Panagiotis, and Anastasios I. Dounis. "Fuzzy Q-Learning Agent for Online Tuning of PID Controller for DC Motor Speed Control." Algorithms 11, no. 10 (2018): 148. http://dx.doi.org/10.3390/a11100148.
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This paper proposes a hybrid Zeigler-Nichols (Z-N) reinforcement learning approach for online tuning of the parameters of the Proportional Integral Derivative (PID) for controlling the speed of a DC motor. The PID gains are set by the Z-N method, and are then adapted online through the fuzzy Q-Learning agent. The fuzzy Q-Learning agent is used instead of the conventional Q-Learning, in order to deal with the continuous state-action space. The fuzzy Q-Learning agent defines its state according to the value of the error. The output signal of the agent consists of three output variables, in which each one defines the percentage change of each gain. Each gain can be increased or decreased from 0% to 50% of its initial value. Through this method, the gains of the controller are adjusted online via the interaction of the environment. The knowledge of the expert is not a necessity during the setup process. The simulation results highlight the performance of the proposed control strategy. After the exploration phase, the settling time is reduced in the steady states. In the transient states, the response has less amplitude oscillations and reaches the equilibrium point faster than the conventional PID controller.
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Jaouadi, Thameur, Mounir Hajji, Mariam Kasmi, et al. "Aloe sp. leaf gel and water glass for municipal wastewater sludge treatment and odour removal." Water Science and Technology 81, no. 3 (2020): 479–90. http://dx.doi.org/10.2166/wst.2020.123.
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Abstract Aloe gel (Alg), which is a natural extract from the Aloe sp. plant, was evaluated in this study for its potential use as a bioflocculant to treat urban wastewater sewage sludge. The gel was used alone and combined with water glass (WG) under controlled conditions in laboratory experiments. Alg was found effective to settle the flocculated sludge rapidly and remove distinctive unpleasant odours of the sludge as highlighted by gas chromatography-mass spectrometry (GC/MS) analysis. Furthermore, Alg was pH tolerant and had no effect in changing the pH of the wastewater. The optimum dose of Alg was 3% at which a sludge volume index (SVI) of 45.4 mL/g was obtained within 30 min settling time. To enhance the treatment performances of Alg, WG was also evaluated as an alkali agent to further reduce the chemical oxygen demand (COD) and ammonia (NH4-N) in the wastewater. At equal doses of 3% of WG and Alg each, the combined treatment outcomes showed high turbidity and NH4-N removals of 83 and 89%, respectively, but the overall COD removal was at best 25%. The settling rate of treated sludge with combined Alg/WG was very rapid giving an SVI of 25.4 mL/g within only 5 min.
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Chen, Yue, Zhuoyuan Ma, Dongmin Ma, et al. "Characteristics of the Coal Fines Produced from Low-Rank Coal Reservoirs and Their Wettability and Settleability in the Binchang Area, South Ordos Basin, China." Geofluids 2021 (April 2, 2021): 1–17. http://dx.doi.org/10.1155/2021/5560634.
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By using proximate analysis, X-ray diffraction mineral analysis, scanning electron microscope, contact angle measurement, and settlement simulation experiment, the coal fines produced from the coalbed methane wells of Binchang area were used to study the characteristics including particle size distribution, composition, morphology, wettability, and settleability. The results show that the particle size of coal fines produced from coalbed methane wells are mainly >20 mesh, ranging of 1-400 μm, and the particle size distribution curve is mainly dominated by the main-secondary bimodal type, with the main peak of 30-300 μm. The particle size from large to small is drill cutting coal fines, flowback coal fines, bailing coal fines, and pipeline filter coal fines. In terms of ash content, coal fines are higher than coal seam, and drilling cuttings are higher than bailing coal fines, while the fixed carbon content of the former is lower than that of the latter. The minerals of coal fines are mainly kaolinite, illite, quartz, and other 6 minerals, and the mineral types of drilling coal fines are the most abundant, while the bailing coal fines only contain illite and quartz. The roundness of coal fine particles ranges from excellent to poor in the order of bailing coal fines, pipeline filter coal fines, flowback coal fines, and drilling cuttings. However, the sorting of drilling cuttings is excellent, and the particle edges are straight, neat, and smooth, while the sorting of bailing coal fines is poor, and the particle edges are curved, uneven, and rough. The contact angles of coal fines are 40.25°-69.5°, indicating hydrophilous. The wettability of bailing coal fines is better than that of drilling cuttings. The particle size has a negative correlation with the wettability effect. The more obvious the modification effect of positive wetting agent is, the worse the modification effect of negative wetting agent is. The modification of surfactant has nothing to do with the particle size of the coal fines, but is closely related to organic components and minerals. The larger the coal particle size, the higher the settling rate, and the higher the ash content and the lower the fixed carbon content, the faster the settling rate. With the dividing point 150 mesh, the settling rate of large particles is mainly affected by particle size, while that of small particles is affected by the composition.
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Pandey, Shantanu Savita, Rajnish Tripathi, and Govindarajan Suresh Kumar. "Weighted Spacer Design for Elevated Temperature Conditions to Mitigate Barite Settling by Identifying Suitable Viscosifier." Key Engineering Materials 846 (June 2020): 282–88. http://dx.doi.org/10.4028/www.scientific.net/kem.846.282.
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Any successful primary cementing operation at elevated temperature condition requires an efficient displacement of fluid surrounding the casing by cement slurry. In such conditions the cement slurry should be designed in such a way that it should be compatible with both cement and drilling mud. To achieve these requirements we designed the cement slurry with weighted spacer. Spacer is a barrier between cement & mud so that they should not mix with each other, also all these fluids should be incompatible inorder to avoid cement aggregation. The displacement efficiency during cementation is directly dependent on discharge rate, but however due to formation fracture pressure constraints, the discharge rate is limited, hence designing spacer becomes very crucial. This phenomenon becomes more pronounced at higher temperature as turbulent flow efficiency reduces due to the presence of weighting agent. The drive of the present work is to identify a suitable viscosifier to avoid settling of weighing agents in spacer and to maintain the stability of rheology admixture at elevated temperature condition. Laboratory tests were performed for compatible deformation and flow of matter with cement slurry-spacer-mud at temperature range (80-140°C) on a rotational viscometer as per the procedure of API RP 10B-2. The volumetric proportions of the cement slurry/spacer and spacer/mud admixtures were prepared with various ratios: 95/5, 75/25, 50/50, 25/75, and 5/95. Rheological compatibility of fluids (cement & spacer and mud & spacer) is evaluated by computing the R-Index Value (R) which is calculated by subtracting highest 100 rpm reading of admixture from highest rpm reading for an individual fluid for the given range of elevated temperature condition. The calculated R-Index Value can then be utilized to comment on fluid compatibility. After finalization of chemical compatibility, rheological hierarchy was achieved by incorporating the friction pressure loss with respect to discharge rate of an individual fluid for the given range of elevated temperature condition. The spacer system used achieved stable compatibility and efficient rheological hierarchy at elevated temperature cementing conditions. In addition, by comparing the results between the two different spacer systems, the role of hydration in attaining rheological compatibility is computed. This study will in turn prove helpful in figuring out the better spacer system which will play a vital role for better displacement and cementation quality.
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Maslennikova, Elena V., and Vasilii V. Ermakov. "Using biochemical agents to intensify the treatment of highly concentrated drilling wastewater." Vestnik MGSU, no. 9 (September 2020): 1274–84. http://dx.doi.org/10.22227/1997-0935.2020.9.1274-1284.
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Introduction. The co-authors have developed a new approach to the treatment of highly concentrated drilling wastewater (DWW). The approach is based on the enzymic degradation of polysaccharides that drilling wastewater contains. The research objective is to perform an experimental evaluation of the ability of this biochemical agent to intensify the process of removal of solid impurities from highly concentrated polysaccharide-containing DWW.
 Materials and methods. The research was performed using standardized test solutions of polysaccharides (carboxymethyl cellulose (CMC), xanthane gum, guar gum), highly concentrated DWW-containing polysaccharides. The reliability of results is ensured by certified methods of analysis, included into the Federal Register of Measurement Procedures and performed by an accredited laboratory, as well as multiple series of experiments.
 Results. The ability of the biochemical agents (brewing waste (BW) and an enzymatic agent (EP)) to intensify the process of removal of solid impurities from highly concentrated DWW-containing polysaccharides is identified experimentally. The efficiency of biochemical agents used in the process of treatment is determined. The biological degradation of CMC and guar gum solutions is faster than the natural biological degradation that involves BW. Depolymerization time is detected for CMC and guar gum solutions that contain EP.
 Conclusions. The co-authors have developed a cheaper and more environmentally friendly alternative to existing solutions. It represents a biological method of solid impurities removal from highly concentrated BWW-containing polysaccharides. The use of brewing waste products (BW) as a source of microorganisms, that trigger the polysaccharide hydrolysis, is theoretically substantiated and experimentally proven as a method of treatment of highly concentrated BWW-containing polysaccharides. The expediency of using biochemical agents (BW and EP in isolation) to accelerate the settling rate of solid components of highly concentrated BWW is proven experimentally.
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Peñas-Garzón, Manuel, Almudena Gómez-Avilés, Jorge Bedia, Juan Rodriguez, and Carolina Belver. "Effect of Activating Agent on the Properties of TiO2/Activated Carbon Heterostructures for Solar Photocatalytic Degradation of Acetaminophen." Materials 12, no. 3 (2019): 378. http://dx.doi.org/10.3390/ma12030378.
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Several activated carbons (ACs) were prepared by chemical activation of lignin with different activating agents (FeCl3, ZnCl2, H3PO4 and KOH) and used for synthesizing TiO2/activated carbon heterostructures. These heterostructures were obtained by the combination of the activated carbons with a titania precursor using a solvothermal treatment. The synthesized materials were fully characterized (Wavelength-dispersive X-ray fluorescence (WDXRF), X-ray diffraction (XRD), Scanning electron microscopy (SEM), N2 adsorption-desorption, Fourier transform infrared (FTIR) and UV-visible diffuse reflectance spectra (UV-Vis DRS) and further used in the photodegradation of a target pharmaceutical compound (acetaminophen). All heterostructures were composed of anatase phase regardless of the activated carbon used, while the porous texture and surface chemistry depended on the chemical compound used to activate the lignin. Among all heterostructures studied, that obtained by FeCl3-activation yielded complete conversion of acetaminophen after 6 h of reaction under solar-simulated irradiation, also showing high conversion after successive cycles. Although the reaction rate was lower than the observed with bare TiO2, the heterostructure showed higher settling velocity, thus being considerably easier to recover from the reaction medium.
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Ren, Ming, Heyan HUANG, and Esmaiel Mirabdollahi. "Finite-Time Consensus Using an Adaptive Terminal Sliding Mode Control Subjected to Input Saturation." Information Technology And Control 49, no. 3 (2020): 412–20. http://dx.doi.org/10.5755/j01.itc.49.3.23879.
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In this paper, finite-time consensus of double-integrator multi-agent systems is investigated. A new adaptive-terminal sliding mode control is proposed to satisfy the goal within a finite time by considering disturbances and input saturation. The problem is solved for two cases. In the first case, the agents are subjected to disturbances with known upper bounds and input saturation parameters. For the case, the control inputs are designed based on a terminal sliding mode technique to achieve the consensus aim within the finite time as a summation of settling and reaching times. Then, a fast terminal sliding mode control is applied and the control inputs are modified to reduce the high dependency of reaching times to initial speeds. In the second case, the upper disturbance bounds are unknown. To handle this problem, the control laws are adopted by an adaptive-terminal sliding mode method. The upper bounds of disturbances are estimated in the finite time. In both cases, the maximum control efforts are adjusted to always be less than the saturation boundary by optional tuning parameters. The proposed methods efficiency is verified by numerical simulations.
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Aslam, Muhammad Muzamil, Liping Du, Zahoor Ahmed, Muhammad Nauman Irshad, and Hassan Azeem. "A Deep Learning-Based Power Control and Consensus Performance of Spectrum Sharing in the CR Network." Wireless Communications and Mobile Computing 2021 (February 18, 2021): 1–16. http://dx.doi.org/10.1155/2021/7125482.
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The cognitive radio network (CRN) is aimed at strengthening the system through learning and adjusting by observing and measuring the available resources. Due to spectrum sensing capability in CRN, it should be feasible and fast. The capability to observe and reconfigure is the key feature of CRN, while current machine learning techniques work great when incorporated with system adaption algorithms. This paper describes the consensus performance and power control of spectrum sharing in CRN. (1) CRN users are considered noncooperative users such that the power control policy of a primary user (PU) is predefined keeping the secondary user (SU) unaware of PU’s power control policy. For a more efficient spectrum sharing performance, a deep learning power control strategy has been developed. This algorithm is based on the received signal strength at CRN nodes. (2) An agent-based approach is introduced for the CR user’s consensus performance. (3) All agents reached their steady-state value after nearly 100 seconds. However, the settling time is large. Sensing delay of 0.4 second inside whole operation is identical. The assumed method is enough for the representation of large-scale sensing delay in the CR network.
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Prasad, Arvind, Peter J. Uggowitzer, Zhi Ming Shi, and Andrej Atrens. "Production of High Purity Mg-X Rare Earth Binary Alloys Using Zr." Materials Science Forum 765 (July 2013): 301–5. http://dx.doi.org/10.4028/www.scientific.net/msf.765.301.
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An Fe content lower than the tolerance limit is critical in controlling corrosion rates of Mg alloys. The possibility of reducing Fe below the tolerance in Mg melts was studied using Zr as a precipitating agent. The experiments were carried out on Mg-X binary alloys with rare-earths, X = Y, Ce, Gd, Nd, and La. The laboratory scale results show that Zr is effective in reducing the Fe content from the Mg melt for Mg-X binary alloys. Purification occurs by the precipitation from the melt of Fe rich precipitates, and the settling of the precipitates to the bottom of the melt. Any desired Fe content down to one wt ppm can in principle be achieved by appropriate melt treatment. The experimental results are discussed with respect to calculated phase diagrams.
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Kocerba-Soroka, Wioleta, Edyta Fiałkowska, Agnieszka Pajdak-Stós, Mateusz Sobczyk, Małgorzata Pławecka, and Janusz Fyda. "Effect of the rotifer Lecane inermis, a potential sludge bulking control agent, on process parameters in a laboratory-scale SBR system." Water Science and Technology 68, no. 9 (2013): 2012–18. http://dx.doi.org/10.2166/wst.2013.453.
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The influence of a high density of rotifers, which is known to be able to control filamentous bacteria, on the parameters of an activated sludge process was examined in four professional laboratory batch reactors. These reactors allow the imitation of the work of a wastewater treatment plant with enhanced nutrient removal. The parameters, including oxygen concentration, pH and temperature, were constantly controlled. The experiment showed that Lecane rotifers are able to proliferate in cyclically anaerobic/anoxic and aerobic conditions and at dissolved oxygen concentrations as low as 1 mg/L. In 1 week, rotifer density increased fivefold, exceeding the value of 2,200 ind./mL. The grazing activity led to an improvement in settling properties. Extremely high numbers of rotifers did not affect the main parameters, chemical oxygen demand (COD), N-NH4, N-NO3, P-PO4 and pH, during sewage treatment. Therefore, the use of rotifers as a tool to limit the growth of filamentous bacteria appears to be safe for the entire wastewater treatment process.
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Cardona, Gustavo A., and Juan M. Calderon. "Robot Swarm Navigation and Victim Detection Using Rendezvous Consensus in Search and Rescue Operations." Applied Sciences 9, no. 8 (2019): 1702. http://dx.doi.org/10.3390/app9081702.
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Cooperative behaviors in multi-robot systems emerge as an excellent alternative for collaboration in search and rescue tasks to accelerate the finding survivors process and avoid risking additional lives. Although there are still several challenges to be solved, such as communication between agents, power autonomy, navigation strategies, and detection and classification of survivors, among others. The research work presented by this paper focuses on the navigation of the robot swarm and the consensus of the agents applied to the victims detection. The navigation strategy is based on the application of particle swarm theory, where the robots are the agents of the swarm. The attraction and repulsion forces that are typical in swarm particle systems are used by the multi-robot system to avoid obstacles, keep group compact and navigate to a target location. The victims are detected by each agent separately, however, once the agents agree on the existence of a possible victim, these agents separate from the general swarm by creating a sub-swarm. The sub-swarm agents use a modified rendezvous consensus algorithm to perform a formation control around the possible victims and then carry out a consensus of the information acquired by the sensors with the aim to determine the victim existence. Several experiments were conducted to test navigation, obstacle avoidance, and search for victims. Additionally, different situations were simulated with the consensus algorithm. The results show how swarm theory allows the multi-robot system navigates avoiding obstacles, finding possible victims, and settling down their possible use in search and rescue operations.
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Gholami, Milad, Alessandro Pilloni, Alessandro Pisano, and Elio Usai. "Robust Distributed Secondary Voltage Restoration Control of AC Microgrids under Multiple Communication Delays." Energies 14, no. 4 (2021): 1165. http://dx.doi.org/10.3390/en14041165.
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This paper focuses on the robust distributed secondary voltage restoration control of AC microgrids (MGs) under multiple communication delays and nonlinear model uncertainties. The problem is addressed in a multi-agent fashion where the generators’ local controllers play the role of cooperative agents communicating over a network and where electrical couplings among generators are interpreted as disturbances to be rejected. Communications are considered to be affected by heterogeneous network-induced time-varying delays with given upper-bounds and the MG is subjected to nonlinear model uncertainties and abrupt changes in the operating working condition. Robustness against uncertainties is achieved by means of an integral sliding mode control term embedded in the control protocol. Then, the global voltage restoration stability, despite the communication delays, is demonstrated through a Lyapunov-Krasovskii analysis. Given the delays’ bounds, and because the resulting stability conditions result in being non-convex with respect to the controller gain, then a relaxed linear matrix inequalities-based tuning criteria is developed to maximize the controller tuning, thus minimizing the restoration settling-time. By means of that, a criteria to estimate the maximal delay margin tolerated by the system is also provided. Finally, simulations on a faithful nonlinear MG model, showing the effectiveness of the proposed control strategy, are further discussed.
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Cha, Hwang, and Kim. "How to Improve Performance and Diversity of Government-Funded Research Institute Ecosystem? Focus on Result Sharing and Feedback Policy." Journal of Open Innovation: Technology, Market, and Complexity 5, no. 3 (2019): 66. http://dx.doi.org/10.3390/joitmc5030066.
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Despite its importance to the performance outcome of an organization, there are very few studies on how feedback mechanism impacts ecosystems of government-funded research institutes (GIs). This study focuses on the effect of the feedback mechanism on the average performance and diversity of a GI ecosystem. Feedback mechanisms consisted of feedback strategy and degree of result sharing. An agent-based model that embeds a genetic algorithm to replicate a real GI ecosystem was used. It was found that relational patterns between average performance and degree of result sharing varied by type of feedback policy. In contrast, convergence time, which refers to the average period of settling the stable state in the perspective of ecosystem diversity, depends on the ratio of result openness rather than the type of feedback policy. This study suggests two plans to improve the GI assessment system by changing the degree of result sharing and feedback type.
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David, Ghislain, Claire Negrell, Laurent Vachoud, Emilie Ruiz, Michèle Delalonde, and Christelle Wisniewski. "An environmental application of functionalized chitosan: enhancement of the separation of the solid and liquid fractions of digestate from anaerobic digestion." Pure and Applied Chemistry 88, no. 12 (2016): 1155–66. http://dx.doi.org/10.1515/pac-2016-0705.
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AbstractA high molecular weight chitosan was chemically modified to quantitatively incorporate quaternary ammonium groups. Its efficiency was evaluated in the liquid-solid separation for various liquors, and compared with the one of a polyelectrolyte usually used for this utilization. The performance of the liquid-solid separation was estimated through the determination of two parameters measured after the screening- settling of the mixture liquor/flocculating agent: the separation efficiency (EV) and the TS removal efficiency (ETS). Apart for liquor 6, TS removal was always better after an addition of functionalized chitosan. Furthermore, whatever the type of liquor, the distribution was modified by an increased presence of high-size particles when functionalized chitosan was added. Moreover, chitosan addition tended to homogenize the size of the particles, which could facilitate the choice of the liquid-solid separation process. This homogenization was particularly observed for the liquor initially highly dispersed in size, i.e. liquors 1, 4, 6 and 8.
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Yang, Yulong, Tingting Cheng, Zhenjiang You, Tuo Liang, and Jirui Hou. "Profile Control Using Fly Ash Three-Phase Foam Assisted by Microspheres with an Adhesive Coating." Applied Sciences 11, no. 8 (2021): 3616. http://dx.doi.org/10.3390/app11083616.
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Foam-assisted steam flooding is a promising technique to alleviate gas channeling and enhance sweep efficiency in heterogeneous heavy-oil reservoirs. However, long-term foam stabilization remains problematic at high temperatures. Three-phase foam (TPF), containing dispersed solid particles, has been proposed to improve foam stability under harsh reservoir conditions. We fabricated a novel TPF system by adding ultrafine fly ash particles, as well as high-temperature resistant microspheres with an adhesive coating layer. This work aims at assessing the ability of the generated TPF in controlling steam channeling and enhancing oil recovery. Static and core flood tests were performed to evaluate foam strength and stability. Our results suggested a stronger foamability at a lower consolidation agent concentration, while a longer half-life period of foam and settling time of solid particles at a larger consolidation agent concentration were observed. Bubbles suspended independently in the liquid phase, with sizes varying from 10 to 100 μm, smaller than that of the conventional foam, suggesting a significant enhancement of foam dispersity and stability. The plugging rate was close to 90% when the temperature was as high as 300 °C, demonstrating a well-accepted plugging effect under high temperatures. A larger pore volume injection of TPF yielded a higher EOR in parallel cores, which substantiated the effectiveness of the three-phase foam system in sealing high-permeability channels.
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Taoufik, Anass, Michael Defoort, Krishna Busawon, Laurent Dala, and Mohamed Djemai. "A Distributed Observer-Based Cyber-Attack Identification Scheme in Cooperative Networked Systems under Switching Communication Topologies." Electronics 9, no. 11 (2020): 1912. http://dx.doi.org/10.3390/electronics9111912.
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This paper studies an approach for detecting cyber attacks against networked cooperative systems (NCS) that are assumed to be working in a cyber-physical environment. NCS are prone to anomalies both due to cyber and physical attacks and faults. Cyber-attacks being more hazardous given the cooperative nature of the NCS may lead to disastrous consequences and thus need to be detected as soon as they occur by all systems in the network. Our approach deals with two types of malicious attacks aimed at compromising the stability of the NCS: intrusion attacks/local malfunctions on individual systems and deception/cyber-attacks on the communication between the systems. In order to detect and identify such attacks under switching communication topologies, this paper proposes a new distributed methodology that solves global state estimation of the NCS where the aim is identifying anomalies in the networked system using residuals generated by monitoring agents such that coverage of the entire network is assured. A cascade of predefined-time sliding mode switched observers is introduced for each agent to achieve a fast estimate of the global state whereby the settling time is an a priori defined parameter independently of the initial conditions. Then, using the conventional consensus algorithm, a set of residuals are generated by the agents that is capable of detecting and isolating local intrusion attacks and communication cyber-attacks in the network using only locally exchanged information. In order to prove the effectiveness of the proposed method, the framework is tested for a velocity synchronization seeking network of mobile robots.
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Wulandari, Ririn Lispita, Eli Mahmud, and Mufrod Mufrod. "FORMULASI SIRUP EKSTRAK ETANOL DAUN PARE (Momordica charantia L.) DENGAN GELATIN SEBAGAI PENGENTAL DAN AKTIVITAS MUKOLITIKNYA." JIFFK : Jurnal Ilmu Farmasi dan Farmasi Klinik 15, no. 2 (2018): 54. http://dx.doi.org/10.31942/jiffk.v15i2.2567.
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ABSTRACTEthanol extract of bitter melon leaves at a concentration of 5% has been shown to have mucolytic activity. For ease of use that is made of dosage forms syrup. Thickening agent serves to increase the viscosity and resist settling process resulting in a stable syrup. Gelatin has the ability to improve settling extract better than other thickening. This study aims to determine the effect of variations in the concentration of gelatin to the physical-chemical properties and activity of ethanol extract syrup mukolitik pare leaves the cow intestine mucus in vitro. Extraction of leaf bitter melon is done by percolation. EEDP was made into three syrup formulas using 1% (FII), 2% (FIII), 3% (FIV) gelatin thickener. There is also syrup without extract and gelatin (FI) as a control. The four syrup formulas were examined for physical chemical properties (organoleptic, homogeneity, pH, viscosity), and tested their mucolytic activity. Data on the results of activity tests in the form of viscosity were analyzed by Kruskal-Wallis followed by Mann-Whitney. Data from organoleptic examination, homogeneity, Ph were analyzed descriptively, while viscosity with Linear Regression. The results showed that EEDP syrup with a gelatin concentration of 1%; 2%; 3% have mucolytic activity. The results of examination of the physico-chemical properties of FII, III, and IV syrups have the same taste and color, sweet and bitter, and are greenish black in color, while FI syrup is sweet and yellowish in color. Homogeneous FI syrup, FIII and FIV syrup are evenly distributed, while FII syrup has coarse particles. Fourth pH normal syrup formula. Increased concentration of gelatin (1%; 2%; 3%) can increase the viscosity of syrupKeywords: ethanol extract of bitter melon leaves, syrup, gelatin
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Li, Chang-hong, Yue-qi Shi, Peng Liu, and Ning Guo. "Analysis of the Sedimentation Characteristics of Ultrafine Tailings Based on an Orthogonal Experiment." Advances in Materials Science and Engineering 2019 (November 28, 2019): 1–13. http://dx.doi.org/10.1155/2019/5137092.
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Due to continuous improvements in the beneficiation process, the size of tailings has decreased. In many mines, more than 50% of the total tailings are finer than 74 μm. Ultrafine tailings exhibit a slow settling velocity and uneven settling, which pose new challenges to the safety and stability of tailings dams. In this paper, ultrafine iron tailings from the Makeng Iron Mine in Longyan City, Fujian Province, were used as the research object. A four-factor, three-level orthogonal test method was used to study the sedimentation characteristics of ultrafine tailings with four common curing agent materials, including polyacrylamide, polyaluminum chloride, polyaluminum sulfate, and polyferric sulfate. The results show that when the pulp concentration is 30%, the polyacrylamide is cationic and the molecular weight is 10 million, the optimal content of the flocculant is 3‰, the optimum dose of the polyaluminum chloride with a content of 28 is 0.1‰, the optimum dose of polyaluminum sulfate is 1‰, and the optimum dose of polymeric ferric sulfate is 1‰. When the flocculant is mixed according to the proportion of 2‰ polyacrylamide, 0.05‰ polyaluminum chloride, 1‰ polyaluminum sulfate, and 1.0‰ polyferric sulfate, the sedimentation speed of the ultrafine tailings is fast, and the supernatant liquid is clear. The results of multivariate nonlinear regression analysis of the sedimentation curve show that the primary and secondary factors affecting sedimentation are polyacrylamide > polyaluminum sulfate > polyaluminum chloride > polyferric sulfate. When the optimal ratio is applied, the cohesion (c) of ultrafine tailings increases from 27 kPa to 68.75 kPa and the internal friction angle (φ) increases from 25.53° to 27.53°, which shows that the shear strength improves and the stability of the tailings dam increases. The economic analysis of the composite flocculant with the optimal ratio shows that the flocculant with the optimal proportion has an obvious economic advantage over polyacrylamide alone.
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Hamelin, Richard C., Richard S. Ferriss, Louis Shain, and Bart A. Thielges. "Prediction of poplar leaf rust epidemics from a leaf-disk assay." Canadian Journal of Forest Research 24, no. 10 (1994): 2085–88. http://dx.doi.org/10.1139/x94-267.
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The reliability of a leaf-disk assay to assess resistance of Populusdeltoides Bartr. to Melampsoramedusae Thuëm. f.sp. deltoidae, the causal agent of poplar leaf rust, was evaluated. Leaf disks of eight host genotypes were inoculated in a spore settling tower with 11 isolates of the pathogen in all possible combinations, and the latent period, infection probability, sporulation, and progeny/parent ratio were recorded. Correlations were established between these measures and measures derived from field epidemics, namely the relative area under the disease progress curve, the apparent rate of infection, the final disease severity, and the number of days before defoliation. Four genotypes were highly resistant to all 11 isolates tested with the leaf-disk assay and to the local inoculum in field tests. Three genotypes were highly susceptible in inoculation assays and were also susceptible in the field. One genotype was highly resistant in inoculation assays but had intermediate resistance in the field. Significant correlations (p < 0.05) were found between all leaf-disk and all field parameters.
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Bansal, B., H. Mu¨ller-Steinhagen, and X. D. Chen. "Effect of Suspended Particles on Crystallization Fouling in Plate Heat Exchangers." Journal of Heat Transfer 119, no. 3 (1997): 568–74. http://dx.doi.org/10.1115/1.2824143.
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The presence of suspended particles in solutions significantly affects the crystallization rate. This study investigates the effects of calcium sulphate (crystallizing) particles and alumina (noncrystallizing) particles on calcium sulphate crystallization fouling in a plate heat exchanger. Calcium sulphate particles are formed during the preparation of calcium sulphate solution due to breakage of calcium sulphate crystals growing on the heat transfer surface. These suspended particles settle on the heat transfer surface and act as nuclei. The availability of extra nucleation sites increases the crystallization rate significantly. These particles can be removed with a filter, and the removal of the particles prevents this extra assistance available for crystallization. Therefore, the crystallization rate is reduced markedly. Alumina particles were purposely added during the preparation of calcium sulphate solutions. These particles attach loosely to the heat transfer surface compared with crystalline deposits which adhere strongly. Therefore, calcium sulphate crystals growing on these particles are removed easily. Also, alumina particles settling on the growth faces of calcium sulphate crystals may act as a distorting agent. This slows down the growth of the crystals.
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Davies, Adam P., Richard A. Watson, Rob Mills, C. L. Buckley, and Jason Noble. "“If You Can't Be With the One You Love, Love the One You're With”: How Individual Habituation of Agent Interactions Improves Global Utility." Artificial Life 17, no. 3 (2011): 167–81. http://dx.doi.org/10.1162/artl_a_00030.
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Simple distributed strategies that modify the behavior of selfish individuals in a manner that enhances cooperation or global efficiency have proved difficult to identify. We consider a network of selfish agents who each optimize their individual utilities by coordinating (or anticoordinating) with their neighbors, to maximize the payoffs from randomly weighted pairwise games. In general, agents will opt for the behavior that is the best compromise (for them) of the many conflicting constraints created by their neighbors, but the attractors of the system as a whole will not maximize total utility. We then consider agents that act as creatures of habit by increasing their preference to coordinate (anticoordinate) with whichever neighbors they are coordinated (anticoordinated) with at present. These preferences change slowly while the system is repeatedly perturbed, so that it settles to many different local attractors. We find that under these conditions, with each perturbation there is a progressively higher chance of the system settling to a configuration with high total utility. Eventually, only one attractor remains, and that attractor is very likely to maximize (or almost maximize) global utility. This counterintuitive result can be understood using theory from computational neuroscience; we show that this simple form of habituation is equivalent to Hebbian learning, and the improved optimization of global utility that is observed results from well-known generalization capabilities of associative memory acting at the network scale. This causes the system of selfish agents, each acting individually but habitually, to collectively identify configurations that maximize total utility.
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Shi, Chunhong, Wenquan Sun, Yongjun Sun, Lei Chen, Yanhua Xu, and Mengdan Tang. "Synthesis, Characterization, and Sludge Dewaterability Evaluation of the Chitosan-Based Flocculant CCPAD." Polymers 11, no. 1 (2019): 95. http://dx.doi.org/10.3390/polym11010095.
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Carboxymethyl chitosan (CMCS), acrylamide, and methacryloxyethyltrimethyl ammonium chloride were used as co-monomers to produce a sludge dewatering agent carboxymethyl chitosan-graft-poly(acrylamide-methacryloxyethyltrimethyl ammonium chloride) (CCPAD) by UV-induced graft polymerization. Single-factor experiments and response surface methodology were employed to investigate and optimize the grafting rate, grafting efficiency, and intrinsic viscosity influenced by the total monomer concentration, CMCS concentration, cationic degree, pH value, and illumination time. The structure, surface morphology, and thermal stability of CCPAD were characterized by infrared spectroscopy, hydrogen nuclear magnetic resonance, X-ray diffraction, scanning electron microscopy, and differential thermal-thermogravimetry. The raw sludge with 97.9% water content was sourced from the concentrated tank of a sewage treatment plant and used in the sludge condition experiments. In addition, CCPAD was applied as the sludge conditioner to investigate the effects of cationic degree, intrinsic viscosity, and pH on the supernatant turbidity, moisture content, specific resistance to filtration, and sludge settling ratio. Moreover, the mechanism of sludge conditioning by CCPAD was discussed by examining the zeta potential and extracellular polymeric substance (EPS) content of the supernatant. The sludge dewatering results confirmed that CCPAD had excellent performance for improving sludge dewaterability.
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Miller, David C. "Infection and Imagination: The Atmospheric Analogy and the Problem of Romantic Culture in America." Prospects 13 (October 1988): 37–60. http://dx.doi.org/10.1017/s0361233300005238.
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The crucial twenty-third chapter of Melville's The Confidence-Man (1857) develops an arresting analogy between the linguistic wiles of the latest avatar of the Confidence-Man (or Devil) and the imagery of infectious atmosphere. The chapter opens with a flood of allusions to the notion of an insidious agent hidden in the air, carrying infection and threatening death: “At Cairo, the old established firm of Fever & Ague is still settling up its unfinished business; that Creole grave-digger, Yellow Jack—his hand at the mattock and spade has not lost its cunning; while Don Saturninus Typhus taking his constitutional with Death, Calvin Edson and three undertakers, in the morass, snuffs up the mephitic breeze with zest.” Eyeing from the boat rail the “swampy and squalid domain” that lies before Cairo, the Missourian, Pitch, peers through the “dubious medium” of a “dank twilight, fanned with mosquitoes, and sparkling with fire-flies” and revolves in his mind a foregoing conversation with the P.I.O. man, who, only moments before, had induced him to pay money for a promised boy servant. He begins to suspect he has been conned.
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Miller, David C. "Infection and Imagination: The Atmospheric Analogy and the Problem of Romantic Culture in America." Prospects 13 (October 1988): 37–60. http://dx.doi.org/10.1017/s0361233300006682.
Full textAbstract:
The crucial twenty-third chapter of Melville's The Confidence-Man (1857) develops an arresting analogy between the linguistic wiles of the latest avatar of the Confidence-Man (or Devil) and the imagery of infectious atmosphere. The chapter opens with a flood of allusions to the notion of an insidious agent hidden in the air, carrying infection and threatening death: “At Cairo, the old established firm of Fever & Ague is still settling up its unfinished business; that Creole grave-digger, Yellow Jack—his hand at the mattock and spade has not lost its cunning; while Don Saturninus Typhus taking his constitutional with Death, Calvin Edson and three undertakers, in the morass, snuffs up the mephitic breeze with zest.” Eyeing from the boat rail the “swampy and squalid domain” that lies before Cairo, the Missourian, Pitch, peers through the “dubious medium” of a “dank twilight, fanned with mosquitoes, and sparkling with fire-flies” and revolves in his mind a foregoing conversation with the P.I.O. man, who, only moments before, had induced him to pay money for a promised boy servant. He begins to suspect he has been conned.
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Rodríguez-López, M. J., E. Garzo, J. P. Bonani, A. Fereres, R. Fernández-Muñoz, and E. Moriones. "Whitefly Resistance Traits Derived from the Wild Tomato Solanum pimpinellifolium Affect the Preference and Feeding Behavior of Bemisia tabaci and Reduce the Spread of Tomato yellow leaf curl virus." Phytopathology® 101, no. 10 (2011): 1191–201. http://dx.doi.org/10.1094/phyto-01-11-0028.
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Breeding of tomato genotypes that limit whitefly (Bemisia tabaci) access and feeding might reduce the spread of Tomato yellow leaf curl virus (TYLCV), a begomovirus (genus Begomovirus, family Geminiviridae) that is the causal agent of tomato yellow leaf curl disease. TYLCV is restricted to the phloem and is transmitted in a persistent manner by B. tabaci. The tomato breeding line ABL 14-8 was developed by introgressing type IV leaf glandular trichomes and secretion of acylsucroses from the wild tomato Solanum pimpinellifolium accession TO-937 into the genetic background of the whitefly- and virus-susceptible tomato cultivar Moneymaker. Results of preference bioassays with ABL 14-8 versus Moneymaker indicated that presence of type IV glandular trichomes and the production of acylsucrose deterred the landing and settling of B. tabaci on ABL 14-8. Moreover, electrical penetration graph studies indicated that B. tabaci adults spent more time in nonprobing activities and showed a reduced ability to start probing. Such behavior resulted in a reduced ability to reach the phloem. The superficial type of resistance observed in ABL 14-8 against B. tabaci probing significantly reduced primary and secondary spread of TYLCV.
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Шиков, Евгений Викторович. "Water vole Arvicola amphibius (Linnaeus, 1758) (Arvicolidae) as an agent of biological control of a tree snail Arianta arbustorum (Linnaeus, 1758) (Mollusca, Gastropoda, Helicidae)." Herald of Tver State University. Series: Biology and Ecology, no. 4(60) (December 25, 2020): 43–54. http://dx.doi.org/10.26456/vtbio171.
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Древесная улитка Arianta arbustorum, в последние десятилетия распространившаяся в центре Русской равнины, стала опасным вредителем сельского хозяйства. Заселяя природные биотопы, она вытесняет аборигенные виды как растений, так и моллюсков. Эффективные меры борьбы с A. arbustorum не разработаны. Даётся оценка жизнедеятельности водяной полёвки Arvicola amphibius по отношению к древесной улитке. Плотность A. arbustorum в саду около нор водяной полёвки 2433 экз/м2, а на удалении 5 метров от нор - 5231 экз/м2. Разница статистически достоверна. Показано, что поедание водяной полёвкой древесных улиток локально снижает их плотность. Водяная полёвка выступает как природный агент биологического контроля A. arbustorum, поддерживающий видовое многообразие в природе. Установлено, что осенью 65% всех взрослых A. arbustorum закапываются в землю, и уже недоступны для поедания водяными полёвками. Кормовые запасы водяной полёвки на зиму из моркови и картофеля обнаружены в 45 м от ближайшего огорода. The Wood snail Arianta arbustorum, which in recent decades has spread in the center of the Russian Plain, has become a dangerous pest of agriculture. Settling natural biotopes, it crowds out indigenous species of both plants and mollusks. Effective control measures against A. arbustorum have not been developed. Here we assess the activity of the water vole Arvicola amphibius in relation to the Wood snail. The density of A. arbustorum in the garden near the water vole burrows is 2433 ind./m2, while at a distance of 5 meters from the burrows it becomes 5231 ind./ m2. The difference is statistically significant. Water vole eating wood snails locally reduce their density. Voles thus act as a natural biological control agent of A. arbustorum, preserving species diversity. In the fall around 65% of A. arbustorum adults burrow into the ground and are no longer available for water voles. Winter fodder stocks of a Water vole with carrots and potatoes were found 45 m from the nearest garden.
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Glenner, Henrik, and Birger Brodin. "Phorbol Ester-Induced Metamorphosis in the Parasitic Barnacle, Loxothylacus Panopaei." Journal of the Marine Biological Association of the United Kingdom 77, no. 1 (1997): 261–64. http://dx.doi.org/10.1017/s0025315400033944.
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In order to induce metamorphosis in cyprids of the parasitic barnacle Loxothylacus panopaei (Gissler) (Cirripedia: Rhizocephala: Kentrogonida), we tested a number of compounds (ZR-512, 20-hydroxyecdysone, 3-isobutyl-l-methylxanthine and phorbol-12,13- dibutyrate) all known to cause metamorphosis in thoracican barnacles. Only one agent, phorbol-12,13-dibutyrate, had an effect and induced cypris larvae to complete metamorphosis without previous attachment. This suggests that diacylglycerol-activated protein kinase C plays a role in the metamorphosis of kentrogonid rhizocephalans.Rhizocephalans are highly specialized crustaceans adapted for parasitic life on decapods. The juvenile parasite passes through an internal growth stage, where a root-like trophic organ invades the tissue and haemocoelic fluid of the host (for detailed information on rhizocephalan life history, see Haeg, 1992). As in free-living barnacles, a cyprid larva is the settling stage, and in thoracicans a juvenile barnacle is formed underneath the carapace of the cyprid larva. However, the rhizocephalans develop a so-called kentrogon, which accomplishes the injection of the primordial parasite (Glenner & Høeg, 1995). The degree of specialization towards a specific host means that the cypris larvae of rhizocephalans are extremely selective in their choice of substrata. They will not settle unless a specific host or part of a host, e.g. the gills, is offered. For this reason, the study of settlement and metamorphosis of these species has met with great difficulties.
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Shauqee, Mohamad Norherman, Parvathy Rajendran, and Nurulasikin Mohd Suhadis. "An Explosion Based Algorithm to Solve the Optimization Problem in Quadcopter Control." Aerospace 8, no. 5 (2021): 125. http://dx.doi.org/10.3390/aerospace8050125.
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This paper presents an optimization algorithm named Random Explosion Algorithm (REA). The fundamental idea of this algorithm is based on a simple concept of the explosion of an object. This object is commonly known as a particle: when exploded, it will randomly disperse fragments around the particle within the explosion radius. The fragment that will be considered as a search agent will fill the local space and search that particular region for the best fitness solution. The proposed algorithm was tested on 23 benchmark test functions, and the results are validated by a comparative study with eight well-known algorithms, which are Particle Swarm Optimization (PSO), Artificial Bee Colony (ABC), Genetic Algorithm (GA), Differential Evolution (DE), Multi-Verse Optimizer (MVO), Moth Flame Optimizer (MFO), Firefly Algorithm (FA), and Sooty Tern Optimization Algorithm (STOA). After that, the algorithm was implemented and analyzed for a quadrotor control application. Similarly, a comparative study with the other algorithms stated was done. The findings reveal that the REA can yield very competitive results. It also shows that the convergence analysis has proved that the REA can converge more quickly toward the global optimum than the other metaheuristic algorithms. For the control application result, the REA controller can better track the desired reference input with shorter rise time and settling time, lower percentage overshoot, and minimal steady-state error and root mean square error (RMSE).
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Liu, Chao, Jianlin Luo, Qiuyi Li, et al. "Preparation and Physical Properties of High-Belite Sulphoaluminate Cement-Based Foam Concrete Using an Orthogonal Test." Materials 12, no. 6 (2019): 984. http://dx.doi.org/10.3390/ma12060984.
Full textAbstract:
Prefabricated building development increasingly requires foam concrete (FC) insulation panels with low dry density (ρd), low thermal conductivity coefficient (kc), and a certain compressive strength (fcu). Here, the foam properties of a composite foaming agent with different dilution ratios were studied first, high-belite sulphoaluminate cement (HBSC)-based FCs (HBFCs) with 16 groups of orthogonal mix proportions were subsequently fabricated by a pre-foaming method, and physical properties (ρd, fcu, and kc) of the cured HBFC were characterized in tandem with microstructures. The optimum mix ratios for ρd, fcu, and kc properties were obtained by the range analysis and variance analysis, and the final optimization verification and economic cost of HBFC was also carried out. Orthogonal results show that foam produced by the foaming agent at a dilution ratio of 1:30 can meet the requirements of foam properties for HBFC, with the 1 h bleeding volume, 1 h settling distance, foamability, and foam density being 65.1 ± 3.5 mL, 8.0 ± 0.4 mm, 27.9 ± 0.9 times, and 45.0 ± 1.4 kg/m3, respectively. The increase of fly ash (FA) and foam dosage can effectively reduce the kc of the cured HBFC, but also leads to the decrease of fcu due to the increase in mean pore size and the connected pore amount, and the decline of pore uniformity and pore wall strength. When the dosage of FA, water, foam, and the naphthalene-based superplasticizer of the binder is 20 wt%, 0.50, 16.5 wt%, and 0.6 wt%, the cured HBFC with ρd of 293.5 ± 4.9 kg/m3, fcu of 0.58 ± 0.02 MPa and kc of 0.09234 ± 0.00142 W/m·k is achieved. In addition, the cost of HBFC is only 39.5 $/m3, which is 5.2 $ lower than that of ordinary Portland cement (OPC)-based FC. If the surface of the optimized HBFC is further treated with water repellent, it will completely meet the requirements for a prefabricated ultra-light insulation panel.
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Reddy, B. R. R. "Laboratory Characterization of Gel Filter Cake and Development of Nonoxidizing Gel Breakers for Zirconium-Crosslinked Fracturing Fluids." SPE Journal 19, no. 04 (2013): 662–73. http://dx.doi.org/10.2118/164116-pa.
Full textAbstract:
Summary Borate or Group 4 metal-crosslinked biopolymer fluids constitute the bulk of gelled-fracturing-fluid volumes used in field-fracture stimulation operations to date. Oxidizing chemicals remain the primary gel breakers to break down the filter cake and establish regained formation permeability or fracture conductivity. These breakers presumably oxidize the polymer backbone, causing chain breakdown and facilitating fluid flowback. Safety hazards associated with the use of bulk quantities are one of the many potential problems associated with the use of oxidizing agents as gel breakers. Proper timing of gel breakdown is of utmost importance with respect to oxidizing gel breakers. Conversely, premature polymer oxidation can cause premature proppant settling. On the other hand, a long delay between the completion of the fracturing operation and activation of the gel breaker could cause the deposition of additional filter cake on fracture faces, which could be difficult to break down. A desirable advancement of designing improved fracturing fluids is to develop nonoxidizing gel breakers that focus on decrosslinking the crosslinked gel structure by reacting with the crosslinking agent, rather than only breaking down the polymer chain. In addition, by insolubilizing such breakers, they can be embedded in the filter cake and, when activated, they can degrade the filter cake completely without leaving any residues. In this paper, synthetic disks of different porosities were used to simulate formation-permeability damage caused by filter cakes formed by Zr-crosslinked, carboxylated guar-based gels, and the results were compared with those measured for uncrosslinked fluids. The filter cakes were formed under different applied-pressure regimes and characterized for their polymer content and filter-cake/filtrate-weight ratios. From flow-rate measurements, it was clear that uncrosslinked base polymer solutions did not cause any permeability damage. Uncrosslinked polymer fluids produced from Zr-crosslinked gels by use of decomplexing, nonoxidizer breakers also did not significantly damage disk permeability compared with the fluids produced from conventional, oxidizer-type breakers. Several ortho-disubstituted aromatic compounds containing polar heteroatoms capable of functioning as potentially strong ligands for zirconium were found to be suitable as decomplexing breakers. Biopolymers containing such functional groups, notably lignosulfonate derivatives, show promise as commercially viable alternatives to oxidizing breakers for metal-crosslinked fracturing fluids.