1kHz, Er3+/Yb3+: glass passively Q-switched microchip laser with long time stable operation

2021 ◽  
Author(s):  
Huaimiao Sun ◽  
Zejun Li ◽  
Zhanda Zhu ◽  
Yonglin Hui ◽  
Hong Lei ◽  
...  
Keyword(s):  
Microchip Laser ◽  
Stable Operation ◽  
Long Time

A Method of Power Generation From Low Temperature Medium

2002 ◽  
Author(s):  
Qingjun Cai ◽  
Chung-Lung Chen
Keyword(s):  
Waste Heat ◽  
Stable Operation ◽  
Vapor Bubbles ◽  
Power Generator ◽  
New Device ◽  
Heating And Cooling ◽  
Higher Power ◽  
Long Time ◽  
Generating Capacity ◽  
Cooling Tube

For a long time, how to utilize waste heat to generate electricity has been an interesting and challenging field for energy scientists. This paper presents a new method, ferrofluid power generator (FPG), which takes advantage of waste heat or solar energy to generate electricity in a multiple heating and cooling tube with alternate ferrofluid slug and vapor bubble structures. Based on this method, a new device, a thermomagnetic engine (TME) composed of a straight vacuum tube, a current induced coil, and magnet & ferrofluid slugs (MFS), was designed. Experimental results show that the expanding vapor bubbles push MFSs to generate drastic and continuous oscillating movements under the effect of heat. The pulse voltage signals from the induced coil demonstrate that the TME has a practical structure, potentially higher power generating capacity, and a stable operation.

scholarly journals Promoters for Improvement of the Catalyst Performance in Methane Valorization Processes

2021 ◽  
Vol 23 (3) ◽  
pp. 147
Author(s):  
I.Z. Ismagilov ◽  
A.V. Vosmerikov ◽  
L.L. Korobitsyna ◽  
E.V. Matus ◽  
M.A. Kerzhentsev ◽  
...  
Keyword(s):  
High Efficiency ◽  
Catalyst Activity ◽  
Operation Mode ◽  
Coke Formation ◽  
Product Yield ◽  
Carbon Accumulation ◽  
Stable Operation ◽  
Coke Content ◽  
Methane Dehydroaromatization ◽  
Long Time

In this work, the introduction of modifying additives in the composition of catalysts is considered as an effective mode of improving functional characteristics of materials for two processes of methane conversion into valuable products – methane dehydroaromatization (DHA of CH4) into benzene and hydrogen and autothermal reforming of methane (ATR of CH4) into synthesis gas. The effect of type and content of promoters on the structural and electronic state of the active component as well as catalyst activity and stability against deactivation is discussed. For DHA of CH4 the operation mode of additives M = Ag, Ni, Fe in the composition of Mo-M/ZSM-5 catalysts was elucidated and correlated with the product yield and coke content. It was shown that when Ag serves as a promoter, the duration of the catalyst stable operation is enhanced due to a decrease in the rate of the coke formation. In the case of Ni and Fe additives, the Ni-Мо and Fe-Mo alloys are formed that retain the catalytic activity for a long time in spite of the carbon accumulation. For ATR of CH4, the influence of M = Pd, Pt, Re, Mo, Sn in the composition of Ni-M catalysts supported on La2O3 or Ce0.5Zr0.5O2/Al2O3 was elucidated. It was demonstrated that for Ni-M/La2O3 catalysts, Pd is a more efficient promoter that improves the reducibility of Ni cations and increases the content of active Nio centers. In the case of Ni-M/Ce0.5Zr0.5O2/Al2O3 samples, Re is considered the best promoter due to the formation of an alloy with anti-coking and anti-sintering properties. The use of catalysts with optimal promoter type and its content provides high efficiency of methane valorization processes.

Minimization of sludge production and stable operational condition of a submerged membrane activated sludge process

2004 ◽  
Vol 50 (9) ◽  
pp. 121-128 ◽  
Author(s):  
C.P. Bhatta ◽  
A. Matsuda ◽  
K. Kawasaki ◽  
D. Omori
Keyword(s):  
Activated Sludge ◽  
Hollow Fiber Membrane ◽  
Membrane Module ◽  
Stable Operation ◽  
Activated Sludge Process ◽  
Conventional Activated Sludge ◽  
Operation Conditions ◽  
Long Time ◽  
Conventional Activated Sludge Process ◽  
Sludge Production

Modification of conventional activated sludge process by adding microfiltration type hollow fiber membrane module offers various advantages. The membrane module is immersed directly in the bioreactor to separate the treated water from the sludge and the modified process is called submerged membrane activated sludge process (SMASP). Bench scale SMASP units were operated at constant flux to study the possibility of minimizing the excess sludge production and stable operation at different SRT and BOD loading. The long SRT developed high stabilized MLSS concentration in the bioreactor and decreased the sludge loading rate [kg-BOD/kg-MLSS·d]. In SMASP, very low sludge yield coefficients (0.04–0.09 kg-MLSS/kg-BOD) were obtained at long SRT (500 d) and small BOD loading (≦0.5 kg/(m3·d)) as compared o conventional activated sludge process and these coefficients showed considerable minimization in excess activated sludge production. At the same operation conditions, suction pressure was also maintained low (< 25 kPa), and then SMASP was operated stably for long time (≈200 d).

scholarly journals Optimization of the Process of Unloading of Iron Ore Raw Materials: The Case of a Steel Plant

2020 ◽  
Vol 18 (3) ◽  
pp. 148-162
Author(s):  
A. T. Popov ◽  
O. A. Suslova ◽  
E. A. Voronkova
Keyword(s):  
Metallurgical Plant ◽  
Iron Ore ◽  
Raw Materials ◽  
Stable Operation ◽  
Sinter Production ◽  
Metallurgical Production ◽  
Agglomeration Process ◽  
Initial Iron ◽  
Long Time ◽  
Main Production

The process of unloading iron ore raw materials of the metallurgical plant to the sinter plant has not been considered for a long time as a particular topic. Over the last years the conditions of metallurgical production have undergone certain changes: its intensification has occurred, which entails the need to re-evaluate parameters of stable operation of sinter production. The objective of the suggested study is to consider the issues of possible technical and technological improvement harmonizing transport flows with the requirements of the main production process. To achieve this goal, a technique of mathematical modelling is used, based on the mathematical apparatus of linear programming; graphic-analytical method; method of probability theory.The issues of the process of unloading, storage of iron ore raw materials, of their preparation for sinter production are primarily considered.The article presents the main positions of the process of optimizing unloading of sinter batch of a metallurgical plant.The general characteristics of the technology of metallurgical production and of each particular process are described. The agglomeration process is considered in more detail. The tables of initial iron ore raw materials for sintering production for certain reporting periods are given, for the sake of clarity, the data of one of the tables are summarized in a diagram. A diagram of a standard trestle-type ore warehouse is considered, which sequentially shows the main processes of sintering production from supply of raw materials to the car dumper to getting through a belt conveyor into a stack, and then into receiving bins. The article also provides an example of formation of piles of iron ore raw materials using manganese limestone.The study is based on a dynamic transport problem with delays (DTPD), which considers time of transportation of goods, the dynamics of production volumes over time, the dynamics of consumption, the dynamics of stocks of suppliers and consumers, dynamics of cost of transportation and storage, dynamics of cost of consumption losses. The study contains several mono-problems with a mono load, which overlap each other, forming a multiplicative overlay of single-product problems.

scholarly journals A Mathematical Model for Control and Optimization of Industrial Rotary Alumina Kiln Process

2020 ◽  
Vol 19 ◽  
Keyword(s):  
Raw Materials ◽  
Fuel Efficiency ◽  
Stable Operation ◽  
Time Interval ◽  
Optimization Approach ◽  
Multiple Control ◽  
Delayed Reaction ◽  
High Fuel Efficiency ◽  
Long Time ◽  
Refractory Life

Temperature is a crucial factor for clinker quality in the Industrial Rotary Alumina Kiln Process(IRAKP). However, the characteristic of the high temperature, complex kinetics, multivariable, non-linearreaction kinetics, long-time delayed reaction and various raw materials make it difficult to accurately controlthe temperature in IRAKP through an existing control technology. This paper proposes a dual-responsesurface-based process control (DRSPC) system for the IRAKP in a novel manner. In the DRSPC, instead ofthe more precise and complicated nonlinear equations, the dual response surface models are fitted to describethe reaction kinetics in the IRAKP and track their standard deviations for stable operation purpose. Because asimultaneous consideration of multiple control targets could address the problem of unstable operation inkilns; the objectives of the DRSPC study are designed as optimizing product quality, minimizing energyconsumption and temperature fluctuations. Therefore, the proposed DRSPC goals are to achieve a uniformquality clinker, a high fuel efficiency, and a long refractory life. A weight optimization approach is used tohandle these multiple objective functions. The proposed DRSPC can estimate the working conditions of a kilnand predict some optimal manipulated variables to the control system in each control time interval forimproving the efficiency of IRAKP. The DRSPC is applied to a real IRAKP for demonstrating itsapplicability and advantages.

scholarly journals Study on the effect of Anammox/Fe0 coupling treatment of nitrate wastewater under neutral conditions

2021 ◽  
Vol 257 ◽  
pp. 01028
Author(s):  
Bing Wang ◽  
Bing Sun ◽  
Yunlong Liu ◽  
Lin Yang
Keyword(s):  
Nitrate Reduction ◽  
Continuous Flow ◽  
Nitrate Content ◽  
Anammox Bacteria ◽  
Stable Operation ◽  
Chemical Effects ◽  
Reduction Efficiency ◽  
Denitration Rate ◽  
Long Time ◽  
Neutral Conditions

Batch experiments were conducted to explore the effect of Anammox bacteria on the nitrate reduction efficiency of Fe0 under neutral conditions and to analyze the ways of its enhancement. The effects of Fe2+ concentration on the activity of Anammox bacteria in the system were investigated by detecting the nitrate content in the system under neutral conditions. The upflow reactor was set to verify the possibility of stable operation of Fe0/Anammox system in continuous flow. The results showed that in neutral environment, Anammox bacteria can significantly promote the reduction of nitrate by Fe0, and the denitration rate can reach more than 75% under the dual biological and chemical effects. In the continuous flow system of nitrate reduction by Fe0/Anammox bacteria, the stable treatment period was about 7 days. Through regular replacement of iron powder, the denitration rate can be maintained at more than 75% for a long time, and the effluent NH4+, NO2- concentration is low. The treatment of nitrate wastewater by zero-valent iron as a reducing agent has been widely paid attention, but the treatment effect is seriously affected by pH. Anammox bacteria were added to coupling with Fe0 can not only promote each other’s reactivity to adapt to more non-ideal environment, but also reduce secondary pollution, which provides a new idea for the practical application of nitrate wastewater treatment.

scholarly journals Multi-channel wireless A/D acquisition system based on NRF24L01 and LABVIEW

2020 ◽  
Vol 309 ◽  
pp. 01001 ◽  
Author(s):  
Yang Gong ◽  
Pan Zhang
Keyword(s):  
Data Transmission ◽  
Wireless Transmission ◽  
Acquisition System ◽  
Harsh Environments ◽  
Stable Operation ◽  
Data Display ◽  
Industrial Control ◽  
Transmission Distance ◽  
Long Time ◽  
Data Acquisition Module

This paper presents a wireless A/D acquisition system based on NRF24L01 and LABVIEW, which can be used to collect A/D data in the harsh environment of industrial production, but the staff can not easily approach or can not persist in the field for a long time. The system mainly by the wireless transmission module NRF24L01 and A/D data acquisition module, which A/D conversion part of the chip using STM32C8T6 own ADC. The computer uses LABVIEW as the host computer for data display and processing. The wireless A/D acquisition system has stable operation, long transmission distance, accurate data transmission, no loss of data, and can be adapted to various industrial control and measurement situations through measurement in different harsh environments of the factory.

200kv superconducting cryo electron microscope

1987 ◽  
Vol 45 ◽  
pp. 642-643
Author(s):  
M. Iwatsuki ◽  
Y. Kokubo ◽  
Y. Harada ◽  
J. Lehman
Keyword(s):  
Electron Microscope ◽  
Structure Analysis ◽  
Organic Materials ◽  
Strong Interactions ◽  
Specimen Preparation ◽  
Great Effort ◽  
Electron Microscopic ◽  
Crystal Fields ◽  
Special Skill ◽  
Long Time

In recent years, the electron microscope has been significantly improved in resolution and we can obtain routinely atomic-level high resolution images without any special skill. With this improvement, the structure analysis of organic materials has become one of the interesting targets in the biological and polymer crystal fields.Up to now, X-ray structure analysis has been mainly used for such materials. With this method, however, great effort and a long time are required for specimen preparation because of the need for larger crystals. This method can analyze average crystal structure but is insufficient for interpreting it on the atomic or molecular level. The electron microscopic method for organic materials has not only the advantage of specimen preparation but also the capability of providing various information from extremely small specimen regions, using strong interactions between electrons and the substance. On the other hand, however, this strong interaction has a big disadvantage in high radiation damage.

A Stationary Solution of High-Energy Electron Reflection (HEER) for An Arbitrary Surface

1990 ◽  
Vol 48 (2) ◽  
pp. 374-375
Author(s):  
YIQUN MA
Keyword(s):  
Stationary Solution ◽  
High Energy ◽  
Bloch Wave ◽  
Dynamical Theory ◽  
High Energy Electron ◽  
Bulk Materials ◽  
Periodic Surface ◽  
Electron Transmission ◽  
Electron Reflection ◽  
Long Time

For a long time, the development of dynamical theory for HEER has been stagnated for several reasons. Although the Bloch wave method is powerful for the understanding of physical insights of electron diffraction, particularly electron transmission diffraction, it is not readily available for the simulation of various surface imperfection in electron reflection diffraction since it is basically a method for bulk materials and perfect surface. When the multislice method due to Cowley & Moodie is used for electron reflection, the “edge effects” stand firmly in the way of reaching a stationary solution for HEER. The multislice method due to Maksym & Beeby is valid only for an 2-D periodic surface.Now, a method for solving stationary solution of HEER for an arbitrary surface is available, which is called the Edge Patching method in Multislice-Only mode (the EPMO method). The analytical basis for this method can be attributed to two important characters of HEER: 1) 2-D dependence of the wave fields and 2) the Picard iteractionlike character of multislice calculation due to Cowley and Moodie in the Bragg case.

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