The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Charles C. Hwang - One of the best experts on this subject based on the ideXlab platform.
-
Efficacy of ultraviolet light in preventing Legionella colonization of a hospital Water distribution system
Water Research, 1995Co-Authors: Zeming Liu, Janet E. Stout, Lawrence Tedesco, Marcie Boldin, Charles C. HwangAbstract:We performed a controlled evaluation of ultraviolet light irradiation of hot and cold Water supplies in a hospital colonized with Legionella by inserting the u.v. units near the "point-of-use". Showers on one wing of a hospital were supplied with u.v.-irradiated Water. Showers on another wing and 20 other outlets served as controls. Cultures prior to the installation of u.v. units showed all outlets to be heavily colonized with L. pneumophila. Despite disinfection of Incoming Water by u.v., Legionella in established niches of the plumbing system continued to survive. Superheat/flush and chlorination was then applied prior to u.v. activation, Although cultures became negative initially, recolonization occurred after 1 month. Scale accumulation on u.v. lamps had compromised the efficacy of u.v. irradiation. Filters were added to prevent scale accumulation on the u.v. lamps and the u.v.-supplied showers remained Legionella-free. U.V. plus prefiltration can prevent Legionella recolonization for at least 4 months after disinfection if the u.v. units are installed near the "point-of-use". Disinfection must be directed not only at Incoming Water, but also at established niches within the existing plumbing system. The advantages of u.v. include easy installation, low expense, and no adverse effects on Water or plumbing.
S.e. Caffaratti - One of the best experts on this subject based on the ideXlab platform.
-
Phosphorus distribution pattern in sediments of natural and constructed wetlands
Ecological Engineering, 2017Co-Authors: G. A. Di Luca, Maria Alejandra Maine, M. M. Mufarrege, H.r. Hadad, M.c. Pedro, Gabriela Cristina Sanchez, S.e. CaffarattiAbstract:Abstract Two constructed wetlands for treating industrial and sewage effluents (CW1 and CW2) and two natural wetlands (NW1 and NW2), located in Argentina, were studied. The aims of the study were (1) to assess the accumulation and distribution pattern of P in the surface sediments of both natural and constructed wetlands, and (2) to evaluate P long-term retention in sediment. In the sediment of all study sites, inorganic P fractions were dominant. Similar Incoming Water composition was determined between NW2 and CW1 and between NW1 and CW2. Water composition governed P concentration and distribution in sediment, being mainly P bound to CaCO3 in CW1 and NW2 and bound to Fe(OOH) in NW1 and CW2. According to Water and sediment characteristics, the four wetlands will continue removing P from Water. Studied wetlands are efficient and sustainable in terms of P retention.
Anders E. Carlsson - One of the best experts on this subject based on the ideXlab platform.
-
Coarse-Grained Model of Underground Thermal Energy Storage Applied to Efficiency Optimization
Energies, 2020Co-Authors: Anders E. CarlssonAbstract:Seasonal storage of thermal energy, by pumping heated Water through a borehole array in the summer, and reversing the Water flow to extract heat in the winter, can ameliorate some of the intermittency of renewable energy sources. Simulation can be a valuable tool in enhancing the efficiency of such storage systems. This paper develops a simple, efficient mathematical model of spatial temperature dynamics that focuses on the radial Water flow in a cylindrical borehole array. The model calculates the time course of the temperature difference between outgoing and Incoming Water accurately, and allows new optimization strategies to be explored easily. A strategy based on discharging Water heated by the array before it reaches the array center can increase the storage capacity by 25% for a system with a 20% smaller radius than the well-studied Drake Landing system. If the density of boreholes is also doubled, the improvement is 29%.
Cheol Ho Choi - One of the best experts on this subject based on the ideXlab platform.
-
Surface S(N)2 reaction by H2O on chlorinated Si(100)-2 x 1 surface.
The journal of physical chemistry. B, 2005Co-Authors: Hee Soon Lee, Yunsoo Kim, Cheol Ho ChoiAbstract:The potential energy surfaces of one, two, and three Water molecule sequential adsorptions on the symmetrically chlorinated Si(100)-2 x 1 surface were theoretically explored with SIMOMM:MP2/6-31G(d). The first Water molecule adsorption to the surface dimer requires a higher reaction barrier than the subsequent second Water molecule adsorption. The lone pair electrons of the Incoming Water molecule nucleophilically attack the surface Si atom to which the leaving Cl group is bonded, yielding an S(N)2 type transition state. At the same time, the Cl abstracts the H atom of the Incoming Water molecule, forming a unique four-membered ring conformation. The second Water molecule adsorption to the same surface dimer requires a much lower reaction barrier, which is attributed to the surface cooperative effect by the surface hydroxyl group that can form a hydrogen bond with the Incoming second Water molecule. The third Water molecule adsorption exhibits a higher reaction barrier than the first and the second Water molecule adsorption channels but yields a thermodynamically more stable product. In general, it is expected that the surface Si-Cl bonds can be subjected to the substitution reactions by Water molecules, yielding surface Si-OH bonds, which can be a good initial template for subsequent surface chemical modifications. However, oversaturations can be a competing side reaction under severe conditions, suggesting that the precise control of surface kinetic environments is necessary to tailor the final surface characteristics.
Jia Ping - One of the best experts on this subject based on the ideXlab platform.
-
CCTA (3) - Study on Irrigation Regime of Double Cropping of Winter Wheat with Summer Maize
Computer and Computing Technologies in Agriculture IV, 2011Co-Authors: Wang Shengfeng, Xu Jianxin, Yang Shuqin, Jia PingAbstract:Winter wheat and summer maize were important grain crops in China, and winter wheat-summer maize continuous cropping was the main tillage method in north China. According to field experiment datas, Jensen models of winter wheat and summer maize were established respectively in this article. To pursue the biggest overall efficiency as object function, the partition of the finite Water between wheat and maize were optimized, the optimal irrigation scheduling of continuous cropping of the two crops were confirmed in different hydrological years on different Incoming Water condition. This paper provided an efficient approach for promoting the reasonable use of agricultural Water resources and enhancing Water use efficiency in north China.
-
Study on Irrigation Regime of Double Cropping of Winter Wheat with Summer Maize
2010Co-Authors: Wang Shengfeng, Xu Jianxin, Yang Shuqin, Jia PingAbstract:Winter wheat and summer maize were important grain crops in China, and winter wheat-summer maize continuous cropping was the main tillage method in north China. According to field experiment datas, Jensen models of winter wheat and summer maize were established respectively in this article. To pursue the biggest overall efficiency as object function, the partition of the finite Water between wheat and maize were optimized, the optimal irrigation scheduling of continuous cropping of the two crops were confirmed in different hydrological years on different Incoming Water condition. This paper provided an efficient approach for promoting the reasonable use of agricultural Water resources and enhancing Water use efficiency in north China.
