Influence of heat–moisture treatment and annealing on functional properties of sorghum starch

Sorghum starch was annealed in excess water at 50 °C for 24 h. Starch was also modified under heat–moisture treatment at 110 °C after adjusting various moisture contents (20, 30 and 40%) for 8 h. Significant decrease in chain lengths of amylose fraction in HMT starches was observed. Heat moisture treated (HMT) and annealed (ANN) starches showed lower granule sizes, swelling power, peak and setback viscosity but higher retrogradation as compared to native starch. HMT starch with addition of 40% moisture showed a decrease in relative crystallinity. HMT and ANN starch gels were observed to be harder than native starch gel.     

Applicability of a coastal morphodynamic model for fluvial environments

The dominant processes of sediment transport and morphological changes are different between rivers and coastal areas. In many situations rivers, estuaries and coasts need to be modelled together in an integrated way. This paper investigates the capability of a freely available, open source, coastal morphodynamic software (XBeach) to estimate sediment transport and morphological changes in fluvial environments. Four benchmark tests were designed to test code performance and included simple unidirectional flow cases, complex topography, fluvial flood flows (hydrographs) and dam break scenarios (fast transient, supercritical flow fields). The results were compared to laboratory experimental results or simulations results from industry standard software. Analysis suggested that the coastal morphodynamic code is able to simulate sediment transport and morphological changes in a fluvial environment, but there are limitations to what can be modelled and the accuracy to which they are modelled. General morphological trends are replicated reasonably well by the code however specific bed forms and rapid erosive responses are less well modelled. Suggestions are made for applicability of the code, code improvement and future work.     

NiFe2O4–Ni3S2 nanorod array/Ni foam composite catalyst indirectly controlled by Fe3+ immersion for an efficient oxygen evolution reaction

A NiFe alloy was designed on nickel foam (NF) as a precursor using cathodic electrodeposition. NiFe₂O₄–Ni₃S₂ nanorods (NRs) composite catalysts were prepared by Fe³⁺ impregnation and further hydrothermal sulfuration methods. NiFe₂O₄–Ni₃S₂ nanosheets (NSs) were also prepared by direct hydrothermal sulfuration of the NiFe alloy for comparison. Compared to the dense NS structure of the NiFe₂O₄–Ni₃S₂ NSs/NF, the NiFe₂O₄–Ni₃S₂ NRs/NF showed better oxygen evolution performance due to its unique weed-like NR array structure composed of additional oxygen evolution reaction (OER) active sites, with a strong electron interaction for Ni and Fe and the active sulfide synergistic effect with oxides. Therefore, Driving a current density of 10 mA cm^?2 only requires an overpotential of 189 mV and the catalyst could provide 100 mA cm^?2 continuously and be constant for more than 80 h in 1.0 M KOH. This experiment indicated that Fe³⁺ immersion had an indirect regulating effect on the morphological growth of the catalyst, which provided a novel concept for designing better OER catalysts.     

A method for the compound fault diagnosis of gearboxes based on morphological component analysis

An improved morphological component analysis (MCA) method is proposed for the compound fault diagnosis of gearboxes. When gear fault and bearing fault occur simultaneously, the compound fault signal of the gearbox contains meshing components (related to the gear fault) and periodic impulse components (related to the bearing fault). The corresponding fault characteristics can be separated by MCA according to the morphological differences of the components. In the proposed method, the optimal dictionary, which can represent the characteristics of bearing faults, is first selected based on the principle of minimum information entropy. Then, the compound fault signal is decomposed into the meshing component and the periodic impulse component using MCA. Finally, the separated components are subjected to the Hilbert envelope spectrum analysis. The faults of the gear and the bearing can be diagnosed according to the envelope spectra of the separated fault signal components. Simulation and experimental studies validate the effectiveness of the proposed method for the compound fault diagnosis of gearboxes.     

Laboratory tests to evaluate effectiveness of wicking geotextile in soil moisture reduction

A new type of woven geotextile, referred to as wicking geotextile, was developed and introduced to the market. Since this wicking geotextile consists of wicking fibers, they can wick water out from unsaturated soils in a pavement structure thus resulting in an increase of soil resilient modulus and enhance performance of roadways. In this study, a physical model test was developed to evaluate the effectiveness of the wicking geotextile in soil moisture reduction for roadway applications. A test box with a dimension of 1041 mm in length, 686 mm in width, and 584 mm in height was used in this study. Two HDPE plastic panels were used to separate the box into two sections, one containing a dehumidifier and the other backfilled with soil. The dehumidifier was adopted to collect the water, which was wicked out from the soil by the wicking geotextile and evaporated into air. Test results show that (1) the wicking geotextile wicked water out from the soil even at the moisture content close to the optimum moisture content and (2) the comparison of soil moisture contents before and after rainfall demonstrated that the wicking geotextile maintained the soil moisture contents after rainfall close to those before rainfall and had an effective distance for the soil moisture reduction.     

An on-line SAX and HMM-based anomaly detection and visualization tool for early disturbance discovery in a dynamic industrial process

In order to achieve an optimum and successful operation of an industrial process, it is important firstly to detect upsets, equipment malfunctions or other abnormal events as early as possible and secondly to identify and remove the cause of those events. Univariate and multivariate statistical process control methods have been widely applied in process industries for early fault detection and localization.The primary objective of the proposed research is the design of an anomaly detection and visualization tool that is able to present to the shift operator – and to the various levels of plant operation and company management – an early, global, accurate and consolidated presentation of the operation of major subgroups or of the whole plant, aided by a graphical form.Piecewise Aggregate Approximation (PAA) and Symbolic Aggregate Approximation (SAX) are considered as two of the most popular representations for time series data mining, including clustering, classification, pattern discovery and visualization in time series datasets. However SAX is preferred since it is able to transform a time series into a set of discrete symbols, e.g. into alphabet letters, being thus far more appropriate for a graphical representation of the corresponding information, especially for the shift operator. The methods are applied on individual time records of each process variable, as well as on entire groups of time records of process variables in combination with Hidden Markov Models. In this way, the proposed visualization tool is not only associated with a process defect, but it allows also identifying which specific abnormal situation occurred and if this has also occurred in the past. Case studies based on the benchmark Tennessee Eastman process demonstrate the effectiveness of the proposed approach. The results indicate that the proposed visualization tool captures meaningful information hidden in the observations and shows superior monitoring performance.     

Hierarchically alloyed Pd–Cu microarchitecture with tunable shapes: Morphological engineering,and catalysis for hydrogen evolution reaction of ammonia borane

Some uniquely microstructured bi/poly-metal alloys containing lesser or no noble metal have been testified to be cost-effective catalysts suitable for solvolytic dehydrogenation of ammonia borane, which expects the intensive study on their morphological engineering and synergistic mechanism. To this, we here introduce a facile and flexible fabricating protocol, i.e. stepwise wet-chemical reduction route, to purposefully modulate the orientated growth of Pd–Cu alloyed crystals via joint operation of adding suitable additives and adjusting temperature. The characterization of phase composition and evaluation of catalytic ability regarding as-fabricated Pd–Cu nanocrystals with diverse morphological features (e.g. concave tetrahedron, cube, polyhedron, nanosphere, nanowire, worm-like, seaurchin-like, flower-like, etc.) demonstrates that the nanocrystals have homogeneous alloyed phase, holding significantly enhanced catalytic activity and durability. The formation of synergistic effect due to charge transfer from Cu to Pd gives rise to electron enrichment around Pd atomic nucleus, facilitating the adsorption of H to form metal-H species, thus promoting the dehydrogenation of ammonia borane. The difference of catalytic activity of the Pd–Cu nanocrystals with different shapes reveals their morphologic dependent nature, endowing the uniquely shaped bimetal nanocrystals with exceptional catalytic performance. The concave tetrahedron shaped Pd–Cu alloyed nanocrystals hold the excellent catalytic activity almost equivalent to that of noble metal Pd, catalyzing hydrolytic reaction of ammonia borane at 298 K with the apparent activation energy of 31.18 kJ/mol, and maintaining 89% of the incipient catalytic ability after 5 recycling runs. Theoretically, the suggested morphologic tuning strategy can be also applied in fabricating other bi/poly metal alloy catalysts, with great practical potential and development prospects.     

Acoustic emission waveform characterization of crack origin and mode in fractured and ASR damaged concrete

Different constituents of concrete can have cracking behavior that varies in terms of the acoustic waveform that is generated. Understanding the waveform may provide insight into the source and behavior of a crack that occurs in a cementitious composite. In this study, passive acoustic emission (AE) was used to investigate the waveform properties of the individual components of concrete (i.e., aggregate, paste, and interfacial transition zone (ITZ)). First, acoustic events produced by cracks generated using mechanical loading in a wedge splitting test were detected. It was observed that cracks that occurred through the aggregate have an AE frequency range between 300 kHz and 400 kHz, while cracks that propagated through the matrix (paste and ITZ) have a frequency range between 100 kHz and 300 kHz. Second, tests were performed using samples that were susceptible to alkali silica reaction; and AE and X-ray computed tomography were used to detect cracking. AE events with a frequency range between 300 kHz and 400 kHz were detected at early ages, suggesting the initiation of cracks within reactive aggregate. At later ages, AE events were detected with frequency ranges of 100–300 kHz, indicating crack development and propagation in the matrix.     

Market distortions and aggregate productivity: Evidence from Chinese energy enterprises

Market distortions can generate resource misallocations across heterogeneous firms and reduce aggregate productivity. This paper measures market distortions and aggregate productivity growth in China's energy sector. We use the wedge between output elasticities and factor shares in revenues to recover a measure of firm-level market distortions. Using data on a large sample of Chinese energy enterprises from 1999 to 2007, our estimations provide strong evidence of the existence of both factor and product market distortions within and across China's various energy industries. The productivity aggregation and decomposition results demonstrate that the estimated aggregate productivity growth (APG) is, on average, 2.595% points per year, of which technological change, resource reallocation, and firm entries and exits account for 1.981, 0.068, and 0.546% points, respectively. The weak contributions of resource reallocation and firm turnover to APG are also found in energy sub-industries, except in the coal industry. Our research suggests that China's energy sector has major potential for productivity gains from resource reallocation through the reduction of market distortions.     

A tree-structured crash surrogate measure for freeways

In this paper, we propose a novel methodology to define and estimate a surrogate measure. By imposing a hypothetical disturbance to the leading vehicle, the following vehicle’s action is represented as a probabilistic causal model. After that, a tree is built to describe the eight possible conflict types under the model. The surrogate measure, named Aggregated Crash Index (ACI), is thus proposed to measure the crash risk. This index reflects the accommodability of freeway traffic state to a traffic disturbance. We further apply this measure to evaluate the crash risks in a freeway section of Pacific Motorway, Australia. The results show that the proposed indicator outperforms the three traditional crash surrogate measures (i.e., Time to Collision, Proportion of Stopping Distance, and Crash Potential Index) in representing rear-end crash risks. The applications of this measure are also discussed.