Fault diagnosis for distillation process based on CNN–DAE

Distillation is the most widely used operation for liquid mixture separation in the chemical industry. It is of great importance to detect and diagnose faults in distillation process. Due to the strong feedback and coupling of processes in a distillation column, it is difficult to use deep auto-encoders(DAEs) alone to achieve good results in detecting and diagnosing faults, in terms of accuracy and efficiency. This paper proposes a hybrid fault-diagnosis model based on convolutional neural networks(CNNs) and DAEs, by integrating the powerful capability of CNN in feature extraction and of DAE in classification. A case study was carried out with the distillation process of depropanization. It is shown that the proposed hybrid model is of good performance compared to other models, in terms of the accuracy of fault detection in such a process. Also, with the increase of structural layers of the CNN–DAE model, the diagnostic accuracy will be improved, with an optimal accuracy of 92.2%.

Inhibition of Axinl in osteoblast precursor cells leads to defects in postnatal bone growth through suppressing osteoclast formation

Axinl is a negative regulator of β-catenin signaling and its role in osteoblast precursor cells remains undefined.In the present studies,we determined changes in postnatal bone growth by deletion of Axinl in osteoblast precursor cells and analyzed bone growth in newborn and postnatal Axin1 O5X mice and found that hypertrophic cartilage area was largely expanded in AxinlOSX KO mice.A larger number of chondrocytes and unabsorbed cartilage matrix were found in the bone marrow cavity of Axin1OSX KO mice.Osteoclast formation in metaphyseal and subchondral bone areas was significantly decreased,demonstrated by decreased TRAPpositive cell numbers,associated with reduction of MMP9-and cathepsin K-positive cell numbers in Axin1 O5X KO mice.OPG expression and the ratio of O p g to Rankl were significantly increased in osteoblasts of Axinl O5X KO mice.Osteoclast formation in primary bone marrow derived microphage(BMM)cells was significantly decreased when BMM cells were cultured with conditioned media(CM)collected from osteoblasts derived from Axin1OSX mice compared with BMM cells cultured with CM derived from WT mice.Thus,the loss of Axinl in osteoblast precursor cells caused increased OPG and the decrease in osteoclast formation,leading to delayed bone growth in postnatal Axin1°sx KO mice.

Optimization of reed-specific degrading bacteria by response surfaces for remediation of crude oil-polluted soil in Xinjiang,China

This paper discussed the optimization of conditions for remediation of crude oil-polluted soil based on pot experiment by applying reed-specific degrading bacteria, and using response surfaces methodology. We took the initial crude oil concentration, the amount of inoculation, the ratio of nitrogen and phosphorus, and the use of surfactant （Tween-80） as independent variables （factors）, and the degrading ratio of crude oil as the dependent variable （response） after a 90-day experiment. The experiment explored the impacts of each independent variable and their interactions on the bioremediation of crude oil-polluted soil using the Box-Behnken design. Working with a simulated forecasting model the study obtained optimization va reed＋specific degrading bacteria, a nitrogen to phosphorus ues for the treatment parameters of 200 g/kg of the ratio of about 6.0. and 0.2% surfactant. Under experimental conditions, for crude oil concentrations of 10, 30 and 50 g/kg, the optimal effects of the treatments achieved 71.87%, 66.61% and 54.52% degradation of the crude oil, respectively. The results can provide a basis for the technical development of plant-microorganism combined bioremediation of crude oil-polluted soil.

High Resolution Laser Excitation Spectra and Franck-Condon Factors of A^(2)Π-X^(2)∑^(+) Electronic Transition of MgF

Magnesium monofluoride(MgF)is proposed as an ideal candidate radical for direct laser cooling.Here,the rotationally resolved laser spectra of MgF for the A^(2)Π-X^(2)∑^(+) electronic transition system were recorded by using laser induced fluorescence technique.The MgF radicals were produced by discharging SF_(6)/Ar gas mixtures between the tips of two magnesium needles in a supersonic jet expansion.We recorded a total of 19 vibrational bands belonging to three sequences of Δv=0,±1 in the region of 348-370 nm.Accurate spectroscopic constants for both X^(2)∑^(+) and A^(2)Π states are determined from rotational analysis of the experimental spectra.Spectroscopic parameters,including the Franck-Condon factors(FCFs),are determined from the experimental results and the Rydberg-Klein-Rees(RKR)calculations.Significant discrepancies between the experimentally measured and RKR-calculated FCFs are found,indicating that the FCFs are nearly independent of the spin-orbit coupling in the A^(2)Π state.Potential energy curves(PECs)and FCFs determined here provide necessary data for the theoretical simulation of the laser-cooling scheme of MgF.

Study of ghost image suppression in polarized catadioptric virtual reality optical systems

Backgrounds This paper introduces a polarized catadioptric virtual reality optical system.With a focus on the issue of serious ghost image in the system,root causes are analyzed based on design principles and optical structure.Methods The distribution of stray light is simulated using Lighttools,and three major ghost paths are selected using the area of the diffuse spot,S d and the energy ratio of the stray light,K as evaluation means.A method to restrain the ghost image through optimization of the structure of the optical system by controlling the focal power of the ghost image path is proposed.Results/Conclusions The results show that the S_(d) for the ghost image path increases by 40%and K decreases by 40%after optimization.Ghost image is effectively suppressed,which provides the theoretical basis and technical support for ghost suppression in a virtual reality optical system.

Study on the adaptability of augmented reality smartglasses for astigmatism based on holographic waveguide grating

Background Augmen ted reality(AR)smartglasses are considered as the next generation of smart devices to replace mobile phones,and are widely concerned.But at present,AR smartglasses are usually designed according to the human normal eyes.In order to experience AR smartglasses perfectly,abnormal eye users must first wear diopters.Methods For people with astigmatism to use AR smartglasses without wearing a diopter lens,a cylindrical lens waveguide grating is designed in this study based on the principle of holographic waveguide grating.First,a cylindrical lens waveguide substrate is constructed for external light deflection to satisfy the users'normal viewing of the real world.Further,a variable period grating structure is established based on the cylindrical lens waveguide substrate to normally emit the light from the virtual world in the optical machine to the human eyes.Finally,the structural parameters of grating are optimized to improve the diffraction efficiency.Results The results show that the structure of cylindrical lens waveguide grating allows people with astigmatism to wear AR smartglasses directly.The total light utilization rate reaches 90%with excellent imaging uniformity.The brightness difference is less than 0.92%and the vertical field of view is 10°.Conclusions This research serves as a guide for AR product designs for people with long/short sightedness and promotes the development of such products.

Structure modeling of activated carbons used for simulating methane adsorption-A review

Activated carbons(ACs)are highly porous materials with a broad range of applications in industry such as gas storage,water and air purification,gas separation,and catalysis.The microstructure for ACs is still not clearly known in spite of their wide industrial uses.There have been efforts to describe the structure of activated carbons experimentally in relation to its methane adsorption characteristics.In this review,it is assumed that natural gas is sorely composed of CH_(4)for simplicity(because CH_(4)is the major component,>90%).Experimental means to unveil the microstructure and many other properties for these ACs have some limitations,to overcome these limitations,ACs structural modeling and simulation become very important to match the properties with the desired methane adsorption characteristics.The major challenge that methane adsorption simulation faces for so long,is the lack of realistic AC models.This paper reviews the current efforts to develop the realistic AC models for methane adsorption,most of the built models are based on experimental carbon structural findings from the previous studies.The structural parameters including pore size distribution(PSD),specific surface area(SSA),pore volume and extent of curvature in the carbon materials and their role to methane adsorption are discussed.The role of chemical properties,such as presence of functional groups and the nature of the functional groups to the adsorption properties of methane,are also introduced.Different pore morphologies(such as slit pore,platelet,spherical,etc.)are studied with their effect on methane adsorption and presented too.It is found that each of the mentioned parameters has its own bearing to methane adsorption.Furthermore,this work analyzes different current techniques used in modeling natural gas adsorption,and the mechanisms are able to reproduce the specific carbon materials for a certain desired set of adsorption characteristic.Some future works are also recommended in this area,so that better representations of ACs can be obtained for methane storage purposes.

Comparative lifecycle greenhouse gas emissions and their reduction potential for typical petrochemical enterprises in China

Petrochemical enterprises have become a major source of global greenhouse gas(GHG)emissions.Yet,due to the unavailability of basic data,there is still a lack of case studies to quantify GHG emissions and provide petrochemical enterprises with guidelines for implementing energy conservation and emission reduction strategies.Therefore,this study conducted a life cycle assessment(LCA)analysis to estimate the GHG emissions of four typical petrochemical enterprises in China,using first-hand data,to determine possible emission reduction measures.The analytical data revealed that Dushanzi Petrochemical(DSP)has the highest GHG emission intensity(1.17 tons CO_(2)e/ton),followed by Urumqi Petrochemical(UP)(1.08 tons CO_(2)e/ton),Dalian Petrochemical(DLP)(average 0.58 tons CO_(2)e/ton)and Karamay Petrochemical(KP)(average 0.50 tons CO_(2)e/ton)over the whole life cycle.At the same time,GHG emissions during fossil fuel combustion were the largest contributor to the whole life cycle,accounting for about 77.31%–94.27% of the total emissions.In the fossil-fuel combustion phase,DSP had the highest unit GHG emissions(1.20 tons CO_(2)e),followed by UP(0.89 tons CO_(2)e).In the industrial production phase,DLP had the highest unit GHG emissions(average 0.13 tons CO_(2)e/ton),followed by UP(0.10 tons CO_(2)e/ton).During the torch burning phase,torch burning under accident conditions was the main source of GHG emissions.It is worth noting that the CO_(2) recovery stage has"negative value,"indicating that it will bring some environmental benefits.Further scenario analysis shows that effective policies and advanced technologies can further reduce GHG emissions.

Target alignment in the Shen-Guang Ⅱ Upgrade laser facility

The Shen-Guang II Upgrade(SG-Ⅱ-U) laser facility consists of eight high-power nanosecond laser beams and one shortpulse picosecond petawatt laser. It is designed for the study of inertial confinement fusion(ICF), especially for conducting fast ignition(FI) research in China and other basic science experiments. To perform FI successfully with hohlraum targets containing a golden cone, the long-pulse beam and cylindrical hohlraum as well as the short-pulse beam and cone target alignment must satisfy tight specifications(30 and 20 μm rms for each case). To explore new ICF ignition targets with six laser entrance holes(LEHs), a rotation sensor was adapted to meet the requirements of a three-dimensional target and correct beam alignment. In this paper, the strategy for aligning the nanosecond beam based on target alignment sensor(TAS) is introduced and improved to meet requirements of the picosecond lasers and the new six LEHs hohlraum targets in the SG-II-U facility. The expected performance of the alignment system is presented, and the alignment error is also discussed.

Beam guiding system geometric arrangement in the target area of high-power laser drivers

With the increasing number of laser beams, the main difficulty in arranging beam guiding systems(BGSs) involves determining the corresponding relationships between the output and input ports to realize the identified light path length of all beams. Given the basic constraints of geometric arrangement, a BGS model is established, and a base-line algorithm is proposed to address the difficulty mentioned above. Boundary conditions of target area and target chamber are discussed to increase the number of laser beams, and a maximum value exists for a specific target area. Finally, the compatibility of a cylindrical hohlraum target chamber with a spherical hohlraum is analyzed, and a moveable final optics assembly is proposed to execute the switch between the two different targets.

Design and performance of final optics assembly in SG-ⅡUpgrade laser facility

In high power laser facility for inertial confinement fusion research, final optics assembly(FOA) plays a critical role in the frequency conversion, beam focusing, color separation, beam sampling and debris shielding. The design and performance of FOA in SG-II Upgrade laser facility are mainly introduced here. Due to the limited space and short focal length, a coaxial aspheric wedged focus lens is designed and applied in the FOA configuration. Then the ghost image analysis,the focus characteristic analysis, the B integral control design and the optomechanical design are carried out in the FOA design phase. In order to ensure the FOA performance, two key technologies are developed including measurement and adjustment technique of the wedged focus lens and the stray light management technique based on ground glass.Experimental results show that the design specifications including laser fluence, frequency conversion efficiency and perforation efficiency of the focus spot have been achieved, which meet the requirements of physical experiments well.

SG-II-Up prototype final optics assembly:optical damage and clean-gas control

The Shenguang-II Upgrade(SG-II Up) facility is an under-construction high-power laser driver with eight beams, 24 kJ energy, 3 ns pulse duration and ultraviolet laser output, in the Shanghai Institute of Optics and Fine Mechanics, China.The prototype design and experimental research of the prototype final optics assembly(FOA), which is one of the most important parts of the SG-II Up facility, have been completed on the ninth beam of the SG-II facility. Thirty-three shots were fired using 1-ω energy from 1000 to 4500 J and 3-ω energy from 500 to 2403 J with a 3 ns square pulse. During the experiments, emphasis was given to the process of optical damage and to the effects of clean-gas control. A numerical model of the FOA generated by the Integrated Computer Engineering and Manufacturing code for Computational Fluid Dynamics(ICEMCFD) demonstrated that a flux within 1–5 l s^(-1) and a 180 s period is effectual to avoid contaminant sputtering to the optics. The presence of surface ‘mooning' damage and surface spots located outside the clear aperture are induced by contaminants such as wire, silica gel and millimeter order fiber and metal.