Cheng Y.-C.,Shanghai University |
Di Q.-F.,Shanghai University |
Gu C.-Y.,Shanghai University |
Ye F.,Shanghai University |
And 2 more authors.
Journal of Hydrodynamics | Year: 2015
Core flow experiment is an important means of simulation experiments to evaluate the effect of displacing agent, but conventionally the internal characteristics in the core cannot be intuitively observed, and then some important information can not be directly acquired by experiments. In this paper, a visualization method was used to detect the water-flooding process by using an improved low field nuclear magnetic resonance imaging (MRI) device, and the images describing the distribution of oil and water were collected. The experimental results show that the distribution of oil and water can be visually detected in an appropriate range of core porosity, and the end effect in many mechanics experiments is found to exist also in natural core flow test, and the influence range is about 0.004 m from the end of a 0.05752 m length natural core. The results also indicate that MRI is an effective tool to study the real time fluid distribution in natural core. © 2015 Publishing House for Journal of Hydrodynamics.
Li Z.-M.,Guangdong University of Technology |
Zeng W.-X.,Guangdong University of Technology |
Gao M.-L.,Shanghai Niumag Corporation |
Luo Z.-B.,Guangdong University of Technology
Wuli Xuebao/Acta Physica Sinica | Year: 2014
Several typical loads are applied to muck specimens to simulate muck ground treatment conditions. Then tests of pore structural distribution of the soil are performed by the method of nuclear magnetic resonance (NMR), for seeking variation of their internal structure under the typical load level and rate, and thus to further determine the muck ground reinforcement mechanism and responses in micro-structure aspect. The results suggest that: (1) the max-pore decreases under a certain load, and the reduction increases with load level; nevertheless, when the impact load reaches a considerable level, both the max-pore and small-pore decrease; (2) the confining stiffness effect of constraint samples induces a decrease in the proportion of large-pore; (3) at a certain load level (680 kPa or less), the loading rate is the key factor determining the relative proportion of maximum void ratio: smaller lading rate will make the void ratio increase, larger lading rate will make the void ratio reduced, and its boundary value is between >0.8 MPa/s and ≤1.6 MPa/s; (4) with a certain load level and rate, an the number of impact times increses, namely as the total energy is enhanced, the large-pore as well as the max-pore considerably decreases; however, this effect will be reduced when the interval time is short and as the number of impact times increases further. i.e. the large-pore effectively decreases. There exists a suitable value of the number of impact times for the muck specimens. These results reflect the rule of different loading effects in the micro of micro fine structure and provide a basis for the design and construction optimization for muck ground improvement. © 2014 Chinese Physical Society.
Zhou R.,Shanghai Ocean University |
Zhou R.,Cornell University |
Wang X.,Shanghai Ocean University |
Hu Y.,Shanghai JiaoTong University |
And 3 more authors.
Postharvest Biology and Technology | Year: 2015
The effects of transport vibration on Hami melon (Cucumis melo var. saccharinus) softening during storage (room temperature) were studied. Hot water (HW) and HW in combination with shellac coating (HW+shellac) were used to reduce melon softening caused by vibration. Changes in flesh firmness, hydrolase activities, cell wall constituents, cell membrane permeability and weight loss were monitored periodically in stored fruits for 28 days following vibration treatment. Magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR) were used to assess the internal morphological characteristics, transverse relaxation times, and water distribution of Hami melons. The results revealed that vibration contributes to Hami melon softening during storage. Compared to HW treatment, HW+shellac was more effective in reducing melon softening by reducing cell wall hydrolase activity, cell membrane leakage, fruit weight loss, and loss of cell wall constituents. The results were confirmed by MRI and NMR. © 2015.
PubMed | Qingdao Agricultural University, Nanjing Agricultural University, Islamia University of Bahawalpur and Shanghai Niumag Corporation
Type: | Journal: Food chemistry | Year: 2016
Emulsion-type sausages were produced, at 80C for either 0, 10, 20 or 30min, using homogeneous Taihu pork batters. Low-field nuclear magnetic resonance (LF-NMR), with or without deuterium oxide (D2O) substitution, evaluated the proton mobility states related to both water and fat molecules, or fat molecules only, respectively, in the sausage samples, during heat-induced gelation. The decreasing trend in the area proportion of main peak T21, reflected a tighter gel structure in emulsion-type sausages. Raman spectra (400-3600cm(-1)) revealed decreased -helix, but increased -sheet, -turns and random coil contents, during the gelling process. Moreover, principal component analysis (PCA) showed significant correlations between secondary protein structures with distribution of water and fat in the gel matrix. Furthermore, this study established the relationship of water and fat protons mobility with changes in secondary protein structures, and described the critical time of gel formation in emulsion-type pork sausages.
Li T.,Nanjing Agricultural University |
Tu C.,Nanjing Agricultural University |
Rui X.,Nanjing Agricultural University |
Gao Y.,Shanghai Niumag Corporation |
And 4 more authors.
Journal of Agricultural and Food Chemistry | Year: 2015
Solid-state fermentation (SSF) of starchy grain is a traditional technique for food and alcoholic beverage production in East Asia. In the present study, low-field nuclear magnetic resonance (LF-NMR) was introduced for the elucidation of water dynamics and microstructure alternations during the soaking, steaming, and SSF of glutinous rice as a rapid real-time monitoring method. Three different proton fractions with different mobilities were identified based on the degree of interaction between biopolymers and water. Soaking and steaming significantly changed the proton distribution of the sample. The different phases of SSF were reflected by the T2 parameters. In addition, the variations in the T2 parameters were explained by the microstructure changes of rice induced by SSF. The fermentation time and T2 parameters were sigmoidally correlated. Thus, LF-NMR may be an effective real-time monitoring method for SSF in starch systems. © 2015 American Chemical Society.
PubMed | Nanjing Agricultural University and Shanghai Niumag Corporation
Type: Evaluation Studies | Journal: Journal of agricultural and food chemistry | Year: 2015
Solid-state fermentation (SSF) of starchy grain is a traditional technique for food and alcoholic beverage production in East Asia. In the present study, low-field nuclear magnetic resonance (LF-NMR) was introduced for the elucidation of water dynamics and microstructure alternations during the soaking, steaming, and SSF of glutinous rice as a rapid real-time monitoring method. Three different proton fractions with different mobilities were identified based on the degree of interaction between biopolymers and water. Soaking and steaming significantly changed the proton distribution of the sample. The different phases of SSF were reflected by the T2 parameters. In addition, the variations in the T2 parameters were explained by the microstructure changes of rice induced by SSF. The fermentation time and T2 parameters were sigmoidally correlated. Thus, LF-NMR may be an effective real-time monitoring method for SSF in starch systems.
Yu Y.,Tongji University |
Sun Z.,Tongji University |
Pang M.,Tongji University |
Yang P.,Shanghai Niumag Corporation
Journal Wuhan University of Technology, Materials Science Edition | Year: 2013
Development of microstructure of early cement paste (0-6 h) was investigated with 1H low-field NMR. It was found that T 2 (transverse relaxation time) distributions of fresh cement paste were bimodal and two peaks were 'long component' and 'short component'. Separation degree of two peaks was a sign of exchange of water within flocculation and outside flocculation. Factors such as water cement ratio, specific surface area and dosage of superplasticizer had influences on the separation degree: the separation degree increased with the water cement ratio; the separation degree of cement paste prepared with cement with a high specific surface area was zero; dosage of superplasticizer will decrease separation degree. Results also suggested that T 2 distribution gradually moved to the left and T 2 of long component and initial fluidity were linearly correlated. © 2013 Wuhan University of Technology and Springer-Verlag Berlin Heidelberg.
Zhenping S.,Tongji University |
Qi L.,Tongji University |
Yang Y.,Tongji University |
Peiqiang Y.,Shanghai Niumag Corporation
Key Engineering Materials | Year: 2013
Early cement paste (0h-6h) made with cement of different Blain specific surface area was investigated with 23MHz 1H low-field NMR. T2 distribution, T2 against age and T2 distributions against age were obtain. Results showed: 1) T2 distribution of fresh cement paste made with cement of common Blain specific surface area has two peaks and corresponded to water within flocculation and among flocculation; 2)T2 against age could reflect a stage-like behavior of cement hydration; 3) T2 distributions against age showed evolution of microstructure in early cement paste. © (2013) Trans Tech Publications, Switzerland.
Liu R.,Chinese Academy of Sciences |
Wu L.,Chinese Academy of Sciences |
Zhang Y.,Chinese Academy of Sciences |
Zhang H.,Chinese Academy of Sciences |
And 3 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2015
Dough mixing is the key step in noodle production, which has a great influence on noodle quality and performance in subsequent processing. During the noodle dough mixing, there is a limited development of gluten due to low water addition (only 30%-37% moisture content), resulting in crumbly dough pieces. Studying the state and distribution of water in noodle dough has important implications for better understanding physical and chemical changes during dough mixing, illuminating the effect of water on noodle processing and providing the guidance for mixing technology optimization. In this study, 3 kinds of wheat flour with different qualities were used as test materials, and the noodle doughs (with the moisture content of 35%) were made by vacuum mixing at different vacuum degrees and mixing time. The state and distribution of water in sheeted noodle dough were determined by low-field nuclear magnetic resonance (LF-NMR) and differential scanning calorimetric (DSC). The correlation between the results of water state detected by the 2 techniques was also analyzed. The results showed that 3 spin-spin relaxation time constants, namely T21, T22 and T23, were identified by the LF-NMR experiments using the Carr-Purcell-Meiboom-Gill (CPMG) pulse sequences. The second category of water (T22, 0.49-21.54 ms) represented the less tightly bound water, and made up almost 80% of the total moisture in noodle dough. The gluten content and quality of wheat flour had influence on the state and distribution of water in noodle dough, and the mobility of water in dough from strong gluten wheat (Jimai 20) was lower than that from other 2 weak gluten wheats. According to the effects of vacuum degree on T2 and its corresponding peak area, the vacuum mixing at 0.06 MPa may promote the interaction of water and gluten protein, and result in a decrease in the molecular mobility of water in noodle dough. And non-vacuum condition or excessive vacuum (0.09 MPa) could also increase the molecular mobility of water in dough. For Jimai 20 and Jimai 22, the mobility of water was low in noodle dough after being mixed for 8 min, and the mixing time of deficiency (4 min) or excess (12 min) could lead to significantly higher water mobility as evidenced by LF-NMR and DSC. While for the flour of Ningchun 4 with low protein and gluten content, the water mobility was low in dough after mixed for 4 min; with mixing time prolonging, the fraction of less mobile water decreased and the more mobile fraction increased. The results of water state in noodle dough measured by LF-NMR and DSC were consistent. The change tendency for the less tightly bound water (T22) detected by LF-NMR was the same to that for freezable water detected by DSC, and the change tendency for the tightly bound water (T21) was the same to that for non-freezable water. LF-NMR technique is accurate, sensitive, convenient and non-destructive, which is the preferred technique to analyze the state and distribution of moisture in food. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
Zhou X.,University of Shanghai for Science and Technology |
Nie S.,University of Shanghai for Science and Technology |
Wang Y.,University of Shanghai for Science and Technology |
Zhang Y.,Shanghai Niumag Corporation Ltd. |
Yang P.,Shanghai Niumag Corporation Ltd.
Yi Qi Yi Biao Xue Bao/Chinese Journal of Scientific Instrument | Year: 2013
Two-dimensional NMR inversion algorithms have been intensively studied all over the world. Aiming at the problem that existing two-dimensional NMR inversion algorithms are either too sensitive to noise or too dependent to the noise estimation, a new noise-fitting based 2D NMR inversion algorithm is proposed. Firstly, wavelet-based filtering is used to extract noise; then the noise distribution is fitted with a white Gaussian noise mathematic model to get the noise variance; and lastly the original data are fitted according to the new defined stop criteria and evolution algorithm. When the fitted residual is comparable or close to the estimated noise level, the iterations stop and the 2D spectrum is obtained. The proposed algorithm was used on the simulation data with different SNRs and multiple groups of experiment acquired data, and data processing was conducted. The results demonstrate that the proposed algorithm has high robustness and accuracy, can meet the inversion requirements of the data with different SNRs in different application fields, and possesses good actual application values.