Hydrogen production via sorption enhanced chemical looping reforming of glycerol using Ni-based oxygen carrier and Ca-based sorbent: Theoretical and experimental study

Wenju Wang 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.2

The sorption enhanced chemical looping reforming of glycerol (SECLRG) was proposed. This processcan produce high purity H2 without need for additional gas separation equipment. Thermodynamic analysis on the reformerof SECLRG was conducted based on the minimization of Gibbs free energy. The results show that the favorable operationconditions for reformer are pressures around 1-20 atm, temperatures around 800 K, oxygen excess number of1, and sorbent excess number of 1. The thermal efficiency with steam addition is higher than that without steam addition. The SECLRG was also examined in a fixed bed reactor, with NiO/Al2O3 and CaO particles as bed material and glycerolas fuel. Experimental results showed that the H2 molar fraction was higher with CaO than without it. Initially, highpurity hydrogen (>95%) was obtained by SECLR of glycerol at 800 K and 1 atm.

SHADOW DETECTION ALGORITHM FOR MOVING VEHICLE DETECTION

Wenju Li,Ying Li 한국멀티미디어학회 2006 한국멀티미디어학회 국제학술대회 Vol.2006 No.-

Detection of moving vehicles is one of the most important tasks in a video traffic Surveillance system.. However, problems arise due to shadows. Shadows can affect the correct localization, measurement and detection of moving vehicles. Shadow detection is critical for robust and reliable vision-based traffic system. The studies show that color information can improve the discrimination between object and shadow. At present, color-based shadow detection methods are mainly for RGB and HSV color spaces. There is one problem in using RGB color space, namely it has three correlated color planes, so the image analysis can not be done in each plane separately. There are two problems in using HSV color space: (1) hue is meaningless when the intensity is very low or very high; and (2) hue is unstable when the saturation is very low. A new shadow detection algorithm is put forward in this paper. The major novelty of the shadow detection technique is hotelling transform is used to achieve un correlated color components, and a shadow measure was defined for shadow detection. The experimental results show that the proposed algorithm is robust to shadow.

Renewable magnetic alginate-graphene oxide hybrid for efficient cationic dye removal

Wenju Liu,Hongjuan Bai,Weiqiang Gao,Zihan Chen,Zhuangzhuang Liu,Zilong Chen,Junhang Chen 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.10

A batch system was applied to investigate the behavior of adsorption of methylene blue (MB) and crystal violet (CV) from aqueous solution using a renewable magnetic alginate composite containing graphene oxide (M-GO/ Alg) in single and binary systems. The surface morphology and chemical structure of the adsorbent were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and vibrating sample magnetometer (VSM) analysis. The experimental data were fitted by the isotherm models and adsorption kinetics. And the maximum adsorption quantity of MB and CV reached 459.85 and 69.46mg/g at 298 K for M-GO/ Alg, respectively, as deduced from Langmuir model. After five successive adsorptive removal cycles for both dyes, no significant performance loss was observed for M-GO/Alg. Moreover, M-GO/Alg was easily separated under an external magnetic field. In binary system, MB and CV exhibited competitive adsorption. The obtained results suggested that M-GO/Alg can be used as an eco-friendly and recyclable adsorbent to remove cationic dyes from aqueous solutions.

ENSO and greenhouse warming

Cai, Wenju,Santoso, Agus,Wang, Guojian,Yeh, Sang-Wook,An, Soon-Il,Cobb, Kim M.,Collins, Mat,Guilyardi, Eric,Jin, Fei-Fei,Kug, Jong-Seong,Lengaigne, Matthieu,McPhaden, Michael J.,Takahashi, Ken,Timmerm Nature Publishing Group, a division of Macmillan P 2015 Nature climate change Vol.5 No.9

The El Niño/Southern Oscillation (ENSO) is the dominant climate phenomenon affecting extreme weather conditions worldwide. Its response to greenhouse warming has challenged scientists for decades, despite model agreement on projected changes in mean state. Recent studies have provided new insights into the elusive links between changes in ENSO and in the mean state of the Pacific climate. The projected slow-down in Walker circulation is expected to weaken equatorial Pacific Ocean currents, boosting the occurrences of eastward-propagating warm surface anomalies that characterize observed extreme El Niño events. Accelerated equatorial Pacific warming, particularly in the east, is expected to induce extreme rainfall in the eastern equatorial Pacific and extreme equatorward swings of the Pacific convergence zones, both of which are features of extreme El Niño. The frequency of extreme La Niña is also expected to increase in response to more extreme El Niños, an accelerated maritime continent warming and surface-intensified ocean warming. ENSO-related catastrophic weather events are thus likely to occur more frequently with unabated greenhouse-gas emissions. But model biases and recent observed strengthening of the Walker circulation highlight the need for further testing as new models, observations and insights become available.

Effects of organic amendments on soil carbon sequestration in paddy fields of subtropical China

Zhang, Wenju,Xu, Minggang,Wang, Xiujun,Huang, Qinhai,Nie, Jun,Li, Zuzhang,Li, Shuanglai,Hwang, Seon Woong,Lee, Kyeong Bo Springer-Verlag 2012 Journal of soils and sediments Vol.12 No.4

A Study on the Reduction of Gossypol Levels by Mixed Culture Solid Substrate Fermentation of Cottonseed Meal

Zhang, Wenju,Xu, Zirong,Sun, Jianyi,Yang, Xia Asian Australasian Association of Animal Productio 2006 Animal Bioscience Vol.19 No.9

The objective of this work was to study the effect of mixed culture solid substrate fermentation of C. tropicalis ZD-3 with A. niger ZD-8 on detoxification of cottonseed meal (CSM), and to investigate the effect of fermentation period, proportion of CSM in substrate, sodium carbonate, minerals and heat treatment on the reduction of free gossypol levels during mixed culture solid substrate fermentation of CSM. Experiment 1: Three groups of disinfected CSM substrate were incubated for 48 h after inoculation with either of the fungi C. tropicalis ZD-3, A. niger ZD-8 or mixed culture (C. tropicalis ZD-3 with A. niger ZD-8). One non-inoculated group was used as the control. Levels of initial and final free gossypol (FG), CP and in vitro CP digestibility were assayed. The results indicated that mixed culture fermentation was far more effective than single strain fermentation, which not only had higher detoxification rate, but also had higher CP content and in vitro digestibility. Experiment 2: CSM substrates were treated according to experimental variables including fermentation period, proportion of CSM in substrate, sodium carbonate, minerals and heat treatment, Then, the treated CSM substrates were inoculated with mixed culture (C. tropicalis ZD-3 with A. niger ZD-8) and incubated at $30^{\circ}C$ for 36 h in a 95% relative humidity chamber. After fermentation ended, FG and CP content of fermented CSM substrate was assayed. The results showed that the appropriate fermentation period was 36 h, and the optimal proportion of CSM in substrate was 70%. Addition of sodium carbonate to CSM substrate was beneficial for fermentative detoxification. Heat treatment could facilitate fermentative detoxification, and supplementation with minerals was instrumental in reducing gossypol levels during mixed culture solid substrate fermentation of CSM.

Pantropical climate interactions

Cai, Wenju,Wu, Lixin,Lengaigne, Matthieu,Li, Tim,McGregor, Shayne,Kug, Jong-Seong,Yu, Jin-Yi,Stuecker, Malte F.,Santoso, Agus,Li, Xichen,Ham, Yoo-Geun,Chikamoto, Yoshimitsu,Ng, Benjamin,McPhaden, Mich American Association for the Advancement of Scienc 2019 Science Vol.363 No.6430

<P><B>Tropical interconnections</B></P><P>The El Niño–Southern Oscillation, which originates in the tropical Pacific, affects the rest of the world's tropics by perturbing global atmospheric circulation. Less appreciated than this influence is how the tropical Atlantic and Indian Oceans affect the Pacific. Cai <I>et al.</I> review what we know about these pantropical interactions, discuss possible ways of improving predictions of current climate variability, and consider how projecting future climate under different anthropogenic forcing scenarios may be improved. They argue that making progress in this field will require sustained global climate observations, climate model improvements, and theoretical advances.</P><P><I>Science</I>, this issue p. eaav4236</P><P>The El Niño–Southern Oscillation (ENSO), which originates in the Pacific, is the strongest and most well-known mode of tropical climate variability. Its reach is global, and it can force climate variations of the tropical Atlantic and Indian Oceans by perturbing the global atmospheric circulation. Less appreciated is how the tropical Atlantic and Indian Oceans affect the Pacific. Especially noteworthy is the multidecadal Atlantic warming that began in the late 1990s, because recent research suggests that it has influenced Indo-Pacific climate, the character of the ENSO cycle, and the hiatus in global surface warming. Discovery of these pantropical interactions provides a pathway forward for improving predictions of climate variability in the current climate and for refining projections of future climate under different anthropogenic forcing scenarios.</P>

CMIP5 모형에서 엘니뇨 feedback 바이어스 와 평균장과의 관계

김선태,Wenju Cai,Fei-Fei Jin 한국기상학회 2015 한국기상학회 학술대회 논문집 Vol.2015 No.4

A High Performance Permanent Magnet Synchronous Motor Servo System Using Predictive Functional Control and Kalman Filter

Shuang Wang,Wenju Zhu,Jian Shi,Hua Ji,Surong Huang 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.6

A predictive functional control (PFC) scheme for permanent magnet synchronous motor (PMSM) servo systems is proposed in this paper. The PFC-based method is first introduced in the control design of speed loop. Since the accuracy of the PFC model is influenced by external disturbances and speed detection quantization errors of the low distinguishability optical encoder in servo systems, it is noted that the standard PFC method does not achieve satisfactory results in the presence of strong disturbances. This paper adopted the Kalman filter to observe the load torque, the rotor position and the rotor angular velocity under the condition of a limited precision encoder. The observations are then fed back into PFC model to rebuild it when considering the influence of perturbation. Therefore, an improved PFC method, called the PFC+Kalman filter method, is presented, and a high performance PMSM servo system was achieved. The validity of the proposed controller was tested via experiments. Excellent results were obtained with respect to the speed trajectory tracking, stability, and disturbance rejection.

Modulator of surface plasmon polariton based cycle branch graphene waveguide

Jun Zhu,Zhengjie Xu,Wenju Xu,Duqu Wei 한국탄소학회 2018 Carbon Letters Vol.25 No.-

At present, an important research area is the search for materials that are compatible with CMOS technology and achieve a satisfactory response rate and modulation efficiency. A strong local field of graphene surface plasmon polariton (SPP) can increase the interaction between light and graphene, reduce device size, and facilitate the integration of materials with CMOS. In this study, we design a new modulator of SPP-based cycle branch graphene waveguide. The structure comprises a primary waveguide of graphene–LiNbO3–graphene, and a secondary cycle branch waveguide is etched on the surface of LiNbO3. Part of the incident light in the primary waveguide enters the secondary waveguide, thus leading to a phase difference with the primary waveguide as reflected at the end of the branch and interaction coupling to enhance output light intensity. Through feature analysis, we discover that the area of the secondary waveguide shows significant localized fields and SPPs. Moreover, the cycle branch graphene waveguide can realize gain compensation, reduce transmission loss, and increase transmission distance. Numerical simulations show that the minimum effective mode field area is about 0.0130l2, the gain coefficient is about 700 cm–1, and the quality factor can reach 150. The structure can realize the mode field limits of deep subwavelength and achieve a good comprehensive performance.