Fatigue testing of subsea pipeline steel connections under combined actions
- Authors: Liu, Huihua , Zhao, Xiao , Xiao, Zhigang
- Date: 2010
- Type: Text , Conference paper
- Relation: Incorporating Sustainable Practice in Mechanics of Structures and Materials - Proceedings of the 21st Australian Conf. on the Mechanics of Structures and Materials p. 649-654
- Full Text: false
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- Description: This paper describes a set of experimental tests of subsea pipeline steel connections under combined forces: one set of force is fatigue load, which is the simulation of the variation caused by currents or waves flowing across pipelines; another set of force is hoop force, which is constant tension force introduced by internal and external pressures. The steel connections are made of two steel plates joined together by single-sided girth welds. One central notch is machined on the weld toe. The specimens under combined forces are compared with those subjected to fatigue loads alone. It is found that the hoop force could affect the fatigue life of subset pipeline steel connections and also reduce the initiation angle of the crack propagation.
The interaction in sorbitol-plasticized starch bionanocomposites via positron annihilation lifetime spectroscopy and small angle X-ray scattering
- Authors: Liu, Huihua , Chaudhary, Deeptangshu , Roberts, Jason , Weed, Ryan , Sullivan, James , Buckman, Stephen
- Date: 2012
- Type: Text , Journal article
- Relation: Carbohydrate Polymers Vol. 88, no. 4 (2012), p. 1172-1176
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- Description: We investigated the free volume variations (size and distribution) within sorbitol plasticized high amylose bionanocomposites of different formula where the interactions among sorbitol, amylose and hydrophilic montmorillonite nanoclay (MMT) modified the crystallinity and therefore, the free volume of the matrix. Positron Annihilation Lifetime Spectroscopy (PALS) is a useful technique to monitor the changes of free volume within the polymer matrix - due to polymer-plasticizer or polymer-polymer interactions. In a recent investigation (Liu et al.; Carbohydrate Polymer, 2011, 85(1), 97-104), we demonstrated that there exists a threshold plasticizer concentration - above which the matrix crystallinity and moisture content can be significantly altered. By investigating the relationship between the changes of free volume and the development of crystalline morphology, we presented evidence that, at the molecular level, the free volume changes due to amylose-MMT interactions were affected by the concentration of the sorbitol plasticizer. The free volume analysis revealed that when the concentration of sorbitol was low (5 wt%), the bionanocomposite showed a bimodal distribution for free volume pore-size. As the sorbitol concentration increased, these free volume pores coalesced. Further, due to sorbitol's hydrophilic nature, this study also presented the evidence of moisture 'lock-in' within the bionanocomposites matrix; only one pore size - was confirmed in the high moisture content samples; meaning that sorbitol was able to have binary interactions with the amylose and with the water molecules so that the free volume pore-size was relatively more uniform. © 2012 Elsevier Ltd. All rights reserved.
Effect of montmorillonite on morphology, glass transition and crystallinity of the xylitol-plasticized bionanocomposites
- Authors: Liu, Huihua , Chaudhary, Deeptangshu
- Date: 2013
- Type: Text , Journal article
- Relation: Carbohydrate Polymers Vol. 98, no. 1 (2013), p. 391-396
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- Description: High amylose based nanocomposites plasticized by xylitol were prepared via twin-screw extrusion. The synergistic interaction in the xylitol-plasticized nanocomposite was studied via various characterization methods and the unique behavior of the xylitol-plasticized nanocomposite had been discussed. As revealed in the XRD and TEM results, good intercalated/exfoliated morphology had been achieved in all the nanocomposites. Furthermore, the expansion of nanoclay basal spacing was related to the xylitol/nanoclay ratio. DSC analysis clearly proved the unique crystallization process of xylitol-plasticized samples. Moreover, in the crystallization domain results, two domains sized at approximately 93.7. Å and 346. Å were found. This observation points to a two-level complex effect from two aggregate domains; one, the re-aggregation of certain number of silicate layers into domains which trap some of the amylose polymer chains, and two, the bulk drying process which combines smaller amylose crystalline domains within a larger amorphous high amylose matrix. © 2013.
- Description: 2003011127
Preparation and characterization of glycerol plasticized (high-amylose) starch-chitosan films
- Authors: Liu, Huihua , Adhikari, Raju , Guo, Qipeng , Adhikari, Benu
- Date: 2013
- Type: Text , Journal article
- Relation: Journal of Food Engineering Vol. 116, no. 2 (2013), p. 588-597
- Full Text: false
- Reviewed:
- Description: The chitosan-starch (high amylose) blend film (1;1), via microfluidization, was prepared by casting with different glycerol concentration (0%, 2.5%, 5% and 10%). The films were characterized for their mechanical, thermal and morphological properties. The addition of glycerol at 5% (w/w) and higher concentrations resulted in decrease in tensile strength, increase in elongation at break due to plasticization. The wellknown antiplasticization was observed in the polymer films with 2.5% of glycerol. The addition of glycerol promoted the interactions among chitosan, starch and glycerol through hydrogen bonding as reflected on the shifting of main peaks of the glycerol-free film to higher wavenumbers as shown by FTIR spectra. The decrease in intensity of glycerol-related peaks in starch-chitosan-glycerol films in both 1H NMR and 13C NMR spectra proved the strong interactions (decrease in glycerol mobility) occurring among starch, chitosan and glycerol in glycerol-plasticized films. © 2012 Elsevier Ltd. All rights reserved.
- Description: C1
Spray drying and encapsulation of omega-3 oils
- Authors: Barrow, Colin , Wang, Bo , Liu, Huihua , Adhikari, Benu
- Date: 2013
- Type: Text , Book chapter
- Relation: Food enrichment with omega-3 fatty acids p. 194-225
- Full Text: false
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The energy consumption and color analysis of freeze/microwave freeze banana chips
- Authors: Jiang, Hao , Zhang, Min , Liu, Yin , Mujumdar, Arun , Liu, Huihua
- Date: 2013
- Type: Text , Journal article
- Relation: Food and Bioproducts Processing Vol. 91, no. 4 (2013), p. 464-472
- Full Text: false
- Reviewed:
- Description: This study investigated the energy consumption of preparing banana chips by freeze drying (FD) and microwave freeze drying (MFD) methods. The results in this study showed that the energy consumption for 400 g fresh banana (about 95 g dried samples) by FD process and MFD process are about 35.73 × 10 6 J (9.92 kW h) and 21.76 × 106 J (6.57 kW h), respectively. Compared to the traditional FD process, MFD can save up to 35.7% energy and 40% drying time. Increasing the heating power in the secondary drying stage of MFD process had been confirmed to result in decrease in both the energy consumption and drying time. After increasing the microwave power in the secondary drying stage from 1.0 W/g to 1.5 W/g in MFD process, total energy consumption is about 18.12 × 106 J (5.56 kW h) and drying time can be reduced from 360 min to 270 min. The sensory evaluation of produced banana chips at different drying conditions (1.0 W/g, 1.5 W/g and 2.0 W/g) revealed that the sensory properties are acceptable by the customers except the 2 W/g microwave power dried product. Thus, the method that increased the heating powder in the secondary drying stage of the MFD process could potentially be an effective method to reduce the energy consumption without seriously sacrificing the color of the end product. © 2013 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
- Description: C1
Ultrasonic treatment and synthesis of sugar alcohol modified Na +-montmorillonite clay
- Authors: Chaudhary, Deeptangshu , Liu, Huihua
- Date: 2013
- Type: Text , Journal article
- Relation: Ultrasonics Sonochemistry Vol. 20, no. 1 (2013), p. 63-68
- Full Text: false
- Reviewed:
- Description: Na +-montmorillonite clay (generally referred to as MMT) is very useful for reinforcing polymeric matrix at very low concentrations (typically, 2-5% wt). These clay particles are typically exfoliated before they can demonstrate the significant gains in heat deflection temperature, modulus, and elongation properties. In the case of hydrophilic biopolymer based matrices, such as carbohydrates and chitosan, exfoliating these nanoclay particles needs greater attention because the exfoliation is typically carried out using hydrophobic oligomers through ion-exchange. This study reports a new method of synthesizing completely hydrophilic MMT-assemblages using hydrophilic plasticizers for biopolymers. We used sugar alcohols (glycerol, xylitol with 3 and 5 hydroxyl groups) and polysaccharide maltodextrin to exfoliate the MMT. Sonication was conducted for MMT nanoclay and plasticizers at different weight ratios. It was confirmed that all plasticizer/modifier led to expansion of MMT gallery spacing (d-spacing) and the change in d-spacing could be related to the molecular structure of the plasticizer. Meanwhile, the extent of exfoliation was maximum with maltodextrin (fully exfoliation with 1:10 and 1:20 ratio of MMT:plasticizer) across all test samples and interestingly, glycerol and xylitol samples quickly established within the MMT galleries and exhibited minimal influence with further increase in relative concentrations. © 2012 Elsevier B.V. All rights reserved.
- Description: 2003010397
Investigations into the free-volume changes within starch/plasticizer/nanoclay systems using Positron Annihilation Lifetime Spectroscopy
- Authors: Liu, Huihua , Chaudhary, Deeptangshu , Campbell, Colin , Roberts, Jason , Buckman, Stephen , Sullivan, James
- Date: 2014
- Type: Text , Journal article
- Relation: Materials Chemistry and Physics Vol. 148, no. 1-2 (2014), p. 349-355
- Full Text: false
- Reviewed:
- Description: The free-volume of a matrix is a fundamental parameter that relates to its molecular and bulk characteristics, such as crystalline change and glass transition behavior. In starch-based bionanocomposite, we investigated the effect of the addition of montmorillonite nanoclay (MMT) and food plasticizers (glycerol and sorbitol) on changes of molecular pore size (including pore volume and pore distribution) using the Positron Annihilation Lifetime Spectroscopy (PALS) method. The results demonstrated counter-intuitive impact of MMT on the total free-volume where the total free-volume increased within the polymeric matrix. When compared to the pure matrix free-volume, the addition of MMT also resulted in the appearance of a broader distribution of the void sizes. The plasticizers, on the other hand, apparently occupied the void spaces, and therefore decreased the free-volume of the matrix. Further, together with the small angle X-ray scattering (SAXS) analysis, we concluded that this is a result of interplay between the plasticizer-plasticizer interactions and the polymer-plasticizer interactions. For example, in the starch/glycerol/MMT system, the pore radii slightly decrease upon the increasing of glycerol amount (OG210 = O.27 nm and OG220 = 0.26 nm), but the relative weight did increase with the increasing glycerol concentration. However, increasing the sorbitol amount increased the pore size from 0.23 nm(OS210) to 0.28 nm(OS220). Furthermore, the addition MMT in the OS010 system, promote the emergence of a new dateable pore radius(0.90 nm), and the total weight significantly increased from 13.70 (OS010) to 19.5% (OS210). We suggest that the pore variation (size and distribution) due to the MMT and plasticizers are reflected in the polymer glass transition and crystallinity because ultimately, the, total free-volume is a reflection of level of interactions existing within the bulk of these nanocomposites.
Microstructure changes of on the extruded high-amylose bionanocomposites as affected by moisture content via synchrotron radiation studies
- Authors: Liu, Huihua , Chaudhary, Deeptangshu
- Date: 2014
- Type: Text , Journal article
- Relation: Solid State Communications Vol. 192, no. (August 2014 2014), p. 10-14
- Full Text: false
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- Description: The crystalline domain changes and lamellar structure observations of sorbitol-plasticized starch nanocomposite had been investigated via synchrotron. Strong interactions were found between amylose-sorbitol, resulting in reduced inter-helix spacing of the starch polymer. Achievable dspacing of nanoclay was confirmed to be correlated to the moisture content (mc) within the nanocomposites. SAXS diffraction patterns changed from circular (high mc samples) to elliptical (low mc samples), indicating the formation of long periodic structure and increased heterogeneities of the electron density within the samples. Two different domains sized at around 90 Ã… and 350 Ã… were found for the low mc samples. However, only the ~90 Ã… domain was observed in high mc samples. Formation of the 380 Ã… domain is attributed to the retrogradation behaviour in the absence of water molecules. Meanwhile, the nucleation effect of nanoclay is another factor leading to the emergence of the larger crystalline domain.
Aggregation behavior in water of amphiphilic diblock copolymers bearing biocompatible phosphorylcholine and cholesteryl groups
- Authors: Ohno, Sayaka , Hasegawa, Shoto , Liu, Huihua , Ishihara, Kazuhiko , Yusa, Shin-ichi
- Date: 2015
- Type: Text , Journal article
- Relation: Polymer Journal Vol. 47, no. 1 (2015), p. 71-76
- Full Text: false
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- Description: Poly(2-(methacryloyloxy)ethyl phosphorylcholine)-block-poly(cholesteryl 6-methacryloyloxyhexanoate) (PMPC 82 -b-PChM n) copolymers with different PChM block lengths were prepared via reversible addition-fragmentation chain transfer controlled/living radical polymerization using a PMPC-based macro-chain transfer agent. The subscript number and n (=3 and 6) refer to the degree of polymerization of the PMPC and PChM blocks, respectively. PMPC 82 -b-PChM n cannot dissolve in water directly due to the strong hydrophobic nature of the PChM block. To prepare the aqueous solution, the diblock copolymer was dissolved in an organic solvent and then dialyzed against pure water. These diblock copolymers formed spherical and rod-like micelles in water, depending on the composition of cholesteryl (Chol) group in the polymer. The prepared aggregates were characterized using static light scattering, dynamic light scattering, transmission electron microscopy and fluorescence probe techniques. The characterization results suggest that the morphology of the polymer aggregates can be controlled from spherical to rod-like micelles by increasing the number of Chol groups in the polymer.
Effects of different freezing methods on the quality and microstructure of lotus (Nelumbo nucifera) root
- Authors: Tu, Jing , Zhang, Min , Xu, Baoguo , Liu, Huihua
- Date: 2015
- Type: Text , Journal article
- Relation: International Journal of Refrigeration Vol. 52, no. (2015), p. 59-65
- Full Text: false
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- Description: The effects of three freezing methods, air blast freezing (ABF), immersion freezing (IF) and ultrasound-assisted immersion freezing (UIF), on quality and microstructure of lotus roots were investigated. The parameters used to evaluate the freezing methods effect were the freezing time, color, firmness, drip loss, vitamin C and microstructure of the final frozen products. The results showed that the UIF products had several advantages in terms of the freezing time, color, firmness and drip loss over ABF and IF. No significant difference (p > 0.05) of vitamin C content was observed between the ABF and IF products, while significant difference (p < 0.05) of vitamin C was observed between UIF and ABF/IF products. ABF caused the largest destruction to the tissue, while the microstructure of the UIF products was the best preserved. It is concluded that UIF processing was a better freezing method for lotus root with improved quality and less damaged microstructure than the two other methods. © 2014 Elsevier Ltd and IIR.
Effects of ultrasound on glass transition temperature of freeze-dried pear (Pyrus pyrifolia) using DMA thermal analysis
- Authors: Islam, Nahidul , Zhang, Min , Liu, Huihua , Xinfeng, Cheng
- Date: 2015
- Type: Text , Journal article
- Relation: Food and Bioproducts Processing Vol. 94, no. (2015), p. 229-238
- Full Text: false
- Reviewed:
- Description: The effect of ultrasound pretreatment at various power (360 W, 600 W and 960 W, frequency 20 kHz) on the glass transition temperature of freeze dried pear (Pyrus pyrifolia) has been studied. DMA temperature plots were divided into four sections (A - glassy region, B - transition region, C - Rubbery plateau region and D - terminal region) with the aim to analyze their properties changed with sonication. Under the same freeze drying condition, with the increase in ultrasonic power, dried pear showed higher glass transition in terms of storage modulus, loss modulus and loss tangent peak. Also a decrease in a
Low oil French fries produced by combined pre-frying and pulsed-spouted microwave vacuum drying method
- Authors: Quan, Xiaojian , Zhang, Min , Fang, Zhongxiang , Liu, Huihua , Shen, Qiaosheng , Gao, Zhongxue
- Date: 2016
- Type: Text , Journal article
- Relation: Food and Bioproducts Processing Vol. 99, no. (2016), p. 109-115
- Full Text: false
- Reviewed:
- Description: French fries were prepared by a combined method of pre-frying and pulsed-spouted microwave vacuum drying (PSMVD). The impact of pre-frying and PSMVD on the quality (oil content, color, texture, microstructure and shrinkage in volume) of French fries was studied and the sample was compared with that of only vacuum fried ones. The results indicated that the French fries prepared by the combined method had lower oil content (25%, db) than that of vacuum-fried sample (40%). Other property analysis also showed that the combined technique processed samples exhibited comparable food texture and color to that of vacuum fried samples, and had a porous microstructure with relatively smaller pore size. It was concluded that the combined method of pre-frying and PSMVD could be an alternative method to produce high quality French fries with low oil content. © 2016 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.