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Vanadium pentoxide film for microsecond pulse generation in 1.5-μm region

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Optoelectronics Letters 2022年第1期18卷 29-34页

作者： mohamad F.Baharom Salam m.Azooz Ahmad H.A.Rosol moh Yasin Sulaiman Wadi Harun Department of Electrical Engineering University of MalayaKuala Lumpur 50603Malaysia Department of Communication Engineering Engineering Technical CollegeAl-Furat Al-Awsat Technical UniversityNajafIraq Department of Physics Faculty of Science and TechnologyAirlangga UniversitySurabaya 60115Indonesia

Q-switched erbium doped fiber laser(EDFL)was passively realized using vanadium pentoxide(V_(2)O_(5))embedded into polyethylene glycol(PEG)film as saturable absorber(SA).The laser could successfully generate stable self-starting pulses when the V_(2)O_(5)film was placed in an EDFL *** operated at 1562.4 nm *** repetition rate can be varied from 91.7 kHz to 128.2 kHz while the pulse width shrank from 10.90μs to 7.81μs with rising pump power from 110.9 mW to 166.5 *** pulse energy recorded was 3.2 nJ at pump power of 166.5 *** results indicate that the saturable absorption of V_(2)O_(5)has promising nonlinear photonic applications especially in fiber laser development for 1.5-μm region.

关键词： pulse pump fiber

CFD modeling of immiscible liquids turbulent dispersion in Kenics static mixers: Focusing on droplet behavior

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Chinese Journal of Chemical Engineering 2020年第2期28卷 348-361页

作者： m.m.Haddadi S.H.Hosseini D.Rashtchian G.Ahmadi Chemical and Petroleum Engineering Department Sharif University of TechnologyTehranIran Department of Chemical Engineering Ilam UniversityIlam 69315–516Iran Department of mechanical and Aeronautical Engineering Clarkson UniversityPotsdamNY 13699-5725USA

The present study is concerned with the computational fluid dynamics(CFD)simulation of turbulent dispersion of immiscible liquids,namely,water–silicone oil and water–benzene through Kenics static mixers using the Eulerian–Eulerian and Eulerian–Lagrangian approaches of the ANSYS Fluent 16.0 *** study the droplet size distribution(DSD),the Eulerian formulation incorporating a population balance model(PBm)was *** the Eulerian–Lagrangian approach,a discrete phase model(DPm)in conjunction with the Eulerian approach for continuous phase simulation was used to predict the residence time distribution(RTD)of *** both approaches,a shear stress transport(SST)k-ωturbulence model was *** validation purposes,the simulated results were compared with the experimental data and theoretical values for the Fanning friction factor,Sauter mean diameter and the mean residence *** reliability of the computational model was further assessed by comparing the results with the available empirical correlations for Fanning friction factor and Sauter mean *** addition,the influence of important geometrical and operational parameters,including the number of mixing elements and Weber number,was *** was found that the proposed models are capable of predicting the performance of the Kenics static mixer reasonably well.

关键词： CFD Liquid–liquid dispersion Kenics static mixer Eulerian–Eulerian approach Eulerian–Lagrangian approach

mapping Floods of Fenton River, an Ungauged Stream in Connecticut

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Journal of Water Resource and Protection 2022年第7期14卷 531-541页

作者： Juan m. Stella Department of Civil and Environmental Engineering Lamar University Beaumont TX USA

The study describes the modeling of flood events of an ungauged river by using recorded data from a neighboring watershed. The Fenton and mount Hope Rivers are two tributaries of the Thames River in Northwest Connecticut, New England. The Fenton River was an ungauged stream until 2006, the mount Hope River has stream discharges measurements since 1940. Due to the lack of discharge measurements in the Fenton River during the XX century, there is a huge uncertainty about the characteristics of past flood events. An analysis was conducted to map the most important floods in the Fenton River around the pump wells of the University of Connecticut (UConn) with simulated peak discharges applying the drainage-area ratio methodology using recorded peak discharges from the mount Hope River in 1955, 2005 and, 2008. Flood maps of the Fenton River were generated applying a one-dimensional (1D) HEC-RAS model for the 1955, 2005, 2008 events and a simulated 2022 flood. The methodology shows that it is possible to simulate flood maps of past events using a neighboring watershed discharges.

关键词： Floodmaps HEC-RAS model Drainage-Area Ratio method Connecticut

Scalable Distributed Sensor Fault Diagnosis for Smart Buildings

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IEEE/CAA Journal of Automatica Sinica 2020年第3期7卷 638-655页

作者： Panayiotis m.Papadopoulos Vasso Reppa marios m.Polycarpou Christos G.Panayiotou IEEE KIOS Research and Innovation Center of Excellence Department of Electrical and Computer EngineeringUniversity of CyprusNicosia 1678Cyprus Department of maritime and Transport Technology Delft University of TechnologyDelft2628 CDThe Netherlands

The enormous energy use of the building sector and the requirements for indoor living quality that aim to improve occupants' productivity and health, prioritize Smart Buildings as an emerging technology. The Heating, Ventilation and Air-Conditioning(HVAC) system is considered one of the most critical and essential parts in buildings since it consumes the largest amount of energy and is responsible for humans comfort. Due to the intermittent operation of HVAC systems, faults are more likely to occur, possibly increasing eventually building's energy consumption and/or downgrading indoor living quality. The complexity and large scale nature of HVAC systems complicate the diagnosis of faults in a centralized framework. This paper presents a distributed intelligent fault diagnosis algorithm for detecting and isolating multiple sensor faults in large-scale HVAC *** the HVAC system as a network of interconnected subsystems allows the design of a set of distributed sensor fault diagnosis agents capable of isolating multiple sensor faults by applying a combinatorial decision logic and diagnostic reasoning. The performance of the proposed method is investigated with respect to robustness, fault detectability and scalability. Simulations are used to illustrate the effectiveness of the proposed method in the presence of multiple sensor faults applied to a 83-zone HVAC system and to evaluate the sensitivity of the method with respect to sensor noise variance.

关键词： Building automation fault diagnosis fault location smart homes

Acceptability and Compliance to a 10-Day Regimen of Zinc Treatment in Diarrhea in Rural Bangladesh

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Food and Nutrition Sciences 2013年第4期4卷 357-364页

作者： Shahnawaz Ahmed Dilruba Nasrin Farzana Ferdous Fahmida Dil Farzana Guddu Kaur mohammod Jobayer Chisti Sumon Kumar Das abu Syed Golam Faruque Centre for Vaccine Development (CVD) University of Maryland School of Medicine Baltimore USA International Centre for Diarrheal Disease Research Dhaka Bangladesh University of Sydney Sydney Australia

We hypothesised that the promotion of blister packs of zinc may be carried out by health personnel in health care facilities to the mothers of children suffering from diarrhea. We predicted that good acceptability and good compliance to zinc treatment in rural Bangladesh would be over 75% and at least 60%, respectively. Between January and December 2011, six hundred and thirty five children aged 6 - 59 months who presented with acute diarrhea received a 10-day zinc regimen. Determination of acceptability and compliance of a dispersible zinc tablet in children 6 - 59 months old was main point of the study. In-home follow-ups started within 2 - 3 weeks after the regimen began. Seventy seven percent of the mothers/caretakers perceived that the taste of the zinc tablets was the same or better than that of other medicines given to their children and expressed willingness to use zinc in the future (good acceptability). Sixty-two percent of the children completed full 10-day course of zinc treatment by taking one tablet a day that had been completely dissolved in a small amount of water (good compliance). There was 63% excess risk for poor compliance to zinc if father stays at home with the family [OR = 1.63 (95%CI;1.09, 2.46) p = 0.019]. Despite vomiting, 33% children continued to receive zinc tablet [OR = 0.67 (95%CI;(0.47, 0.97, 0.032)] after adjusting for co-variates. Both acceptability and compliance to dispersible zinc tablets in childhood diarrheal illnesses are still not at the expected level in rural Bangladesh.

关键词： Acceptability Compliance Diarrhea Young Children Zinc

WASO: Why Does It Increase with Age?

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Journal of Behavioral and Brain Science 2022年第4期12卷 164-176页

作者： James m. Gregory Professor Emeritus Texas Tech University Lubbock TX USA

Insomnia is a common sleep disorder, especially for seniors. WASO (time awake after sleep onset), a component of insomnia, tends to increase with age. There are also many variations in WASO for seniors. To better understand the nature of insomnia, an equation was developed to predict WASO using maximum oxygen uptake (VO2max) as a measure of fitness associated with aerobic exercise. Predictions from the equation matched measured values with an R2 = 0.98. The results were highly significant (p 2max as a function of age and relative fitness (a measure of aerobic fitness independent of age). The two equations were combined to predict WASO as a function of age, gender, and relative fitness. Based on these results, it appears that aerobic exercise to improve relative fitness can be used to reduce WASO. The WASO model explains the numerous reports of reduced WASO associated with long-term exercise programs. The model also explains why WASO increases with age and why high WASO values associate with early death.

关键词： WASO Time Awake Sleep Disorders Sleep Quality Aerobic Exercise

mechanism of the Initial Stage of Thermal Decomposition of Nitroguanidine

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火炸药学报 2023年第1期46卷 31-40页

作者： Boris E.Krisyuk Danila A.markin Timofey m.Sypko Viktor V.Zakharov Nikita V.Chukanov Boris L.Korsunskiy Federal Research Center of Problems of Chemical Physics and medicinal Chemistry Russian Academy of Sciences142432prosp.Academician Semenov1ChernogolovkaMoscow RegionRussia Plekhanov Russian University of Economics Department of Chemistry and Physics36 Stremyanny laneMoscow 117997Russia Lomonosov moscow State University Faculty of Fundamental Physical and Chemical engineeringGSP-11 Leninskie Goryp.51Moscow 119991Russia N.N.Semenov Federal Research Center for Chemical Physics Russian Academy of Science 4 Kosygina StreetBuilding 1Moscow 119991Russia

A theoretical and experimental study of the thermal decomposition of nitroguanidine(NQ) has been carried out. Various thermolysis channels were studied by quantum chemistry methods at the CCSD(or DLPNO-CCSD) level using the aug-cc-pVDZ basis set. It is shown that the lowest activation enthalpies(170-180kJ/mol) are characteristic of the reactions of NO2abstraction from the initial NQ and the reaction channel with the transfer of oxygen from the nitro group to carbon in the limiting stage. Additionally, the thermolysis of NQ was studied experimentally in a nonisothermal mode with heating rates from 1 to 10K/min. In these experiments, the weight loss of the sample, thermal effects, and mass spectra of the products were recorded. An analysis of the experimental data confirmed the results of a theoretical study of the mechanism of thermal decomposition of NQ. The main thermolysis products are N2O, HNCO, NH3, and NO2, which fully corresponds to quantum chemical calculations.

关键词： primary thermolysis steps quantum-chemical calculation mass spectrometry DSC TG

Biogenic amino acid methionine-based corrosion inhibitors of mild steel in acidic media

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International Journal of minerals,metallurgy and materials 2019年第4期26卷 467-482页

作者： L.K.m.O.Goni m.A.Jafar mazumder S.A.Ali m.K.Nazal H.A.Al-muallem Chemistry Department King Fahd University of Petroleum and Minerals

N,N-Diallyl methionine ethyl ester hydrochloride 5 underwent alternating copolymerization with SO_2 via the Butler cyclopolymerization protocol in dimethyl sulfoxide(DmSO) to give water-soluble cycloterpolymer 6 with a ～1:1 molar ratio of sulfide and sulfoxide groups as a result of oxygen transfer from DmSO. Half of the sulfide groups in 6, upon oxidation with H_2O_2, afforded polymer sulfoxide 7 and polymer sulfone 8. The solution properties of these polymers were determined via a viscometric technique. The thermal stability of these polymers was determined by thermogravimetric analysis. The inhibition efficiency obtained from gravimetric mass loss, potentiodynamic polarization, and electrochemical impedance spectroscopy techniques agreed well with each other. The corrosion efficiencies increase with increasing concentration of the polymers. At a polymer concentration of 175 mm, the maximum inhibition efficiency of copolymer compounds 6–8 was determined to be 92%, 97%, and 95%, respectively. The synthesized polymer compounds acted as mixed-type inhibitors. Polymer compound 7 adsorbed onto the metal surface via chemisorption and physisorption and obeyed Langmuir, Temkin, and Freundlich adsorption isotherms. Analyses by X-ray photoelectron spectroscopy and scanning electron microscopy–energy-dispersive X-ray spectroscopy indicated that the adsorbed polymers formed a thin film on the metal surface and prevented further corrosive attack.

关键词： cyclopolymerization methionine methionine sulfoxide methionine sulfone diallylamine salt corrosion inhibition

The dynamics of a nanosecond gas discharge development with an extended slot cathode in argon

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Plasma Science and Technology 2020年第12期22卷 78-88页

作者： N A ASHURBEKOV K O ImINOV G S SHAKHSINOV m Z ZAKARYAEVA K m RABADANOV Dagestan State University Faculty of PhysicsMakhachkala 367000Russia Institute of Physics DFRC of RASMakhachkala 367015Russia

The article presents the results of an experimental study and numerical modelling for the formation and development dynamics of a high-voltage transverse nanosecond discharge generated by a slot cathode in an argon medium at a pressure range of 1–10 Torr. Numerical modelling was carried out under similar experimental conditions for the processes of formation and propagation of ionisation waves, electron density distribution, excited atom and average electron energy in the discharge gap, including the cavity inside the cathode. At a pressure of p=1 Torr, a classical version of a high-voltage discharge is demonstrated to take place with no penetration of the plasma into the cathode cavity and no observed hollow cathode effect. An increase in gas pressure to 5 Torr leads to a penetration of plasma into the cathode cavity with the formation of a cathodic potential drop(CPD) region. Electrons emitted from the side surfaces of the cavity pass through the CPD region without collisions, oscillate inside the cathode cavity;the hollow cathode effect is fully manifested. At р=10 Torr, the modelling results qualitatively coincide with the results at р=5 Torr;in this case, however, hardly any accelerated electrons are observed in the gap between the electrodes, due to their energetic relaxation both inside the cathode cavity and when exiting from it. In both cases, the plasma structure formed at the exit of the cathode cavity involves a concentration of charged particles an order of magnitude higher than that in the rest of the gap, leading to a self-limiting discharge current effect. The results of the numerical modelling are in good agreement with experimental data.

关键词： nanosecond gas discharge numerical simulation argon excited atoms