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1

Effect of Strain Rate on the Microstructure of Warm-Deformed Ultrafined Medium-Carbon Steel

Yuan Q., Xu G., Liu S., Liu M., Hu H.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 4

1805--1813

EN

In this study, medium-carbon steel was subjected to warm deformation experiments on a Gleeble 3500 thermosimulator machine at temperatures of 550°C and 650°C and strain rates of 0.001 s-1 to 1 s-1. The warm deformation behavior of martensite and the effects of strain rate on the microstructure of ultrafine grained medium-carbon steel were investigated. The precipitation behavior of Fe3C during deformation was analyzed and the results showed that recrystallization occurred at a low strain rate. The average ultrafine ferrite grains of 500 ± 58 nm were fabricated at 550°C and a strain rate of 0.001 s-1. In addition, the size of Fe3C particles in the ferrite grains did not show any apparent change, while that of the Fe3C particles at the grain boundaries was mainly affected by the deformation temperature. The size of Fe3C particles increased with the increasing deformation temperature, while the strain rate had no significant effect on Fe3C particles. Moreover, the grain size of recrystallized ferrite decreased with an increase in the strain rate. The effects of the strain rate on the grain size of recrystallized ferrite depended on the deformation temperature and the strain rate had a prominent effect on the grain size at 550°C deformation temperature. Finally, the deformation resistance apparently decreased at 550°C and strain rate of 1 s-1 due to the maximum adiabatic heating in the material.

2

Combined Influence of Silicon Content and Oxygen Concentration on the Oxidation Process of Silicon-Containing Steels

Yuan Q., Xu G., Zhou M., He B., Hu H.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 1

445--450

EN

The combined influence of silicon content and oxygen concentration on silicon-containing steels was investigated, via a heating route similar to that applied in the industrial reheating process, using a Simultaneous Thermal Analyzer (STA). Four different oxygen concentrations and three different isothermal holding times were designed. The results show that the effect of silicon on the mass gain depends on the oxygen concentration and the oxidation time. The mass gain of low-silicon steel is greater than that of high-silicon steel at 1260°C in the oxygen concentrations of 1.0 vol.% and 2.0 vol.%, even when the isothermal holding time is 90 minutes. However, there is a critical time point for mass gain in oxygen concentrations ≥3.0 vol.%. The mass gain of lowsilicon steel is greater before and smaller after this critical point. The critical time is deferred with decreasing oxygen concentration.

3

Three-dimensional distributed DC/IP method for altered tectonite-type gold ore deposits exploration: a case study of the Jiaojia gold metallogenic belt, Eastern China

Yan J., Zhang Y., Zhang K., Zhang Y., Hu H., Wang Z.

Acta Geophysica

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2018

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Vol. 66, no. 4

541--557

EN

To develop an effective method to identify ore-controlling faults, we studied the Jiaojia gold metallogenic belt, a most typical altered tectonite-type gold metallogenic belt in the Jiaodong Peninsula, China, and conducted experiments using the 3D distributed direct current-induced polarization (DC/IP) method. Firstly, we tested the ability of using 3D distributed DC/IP method to identify altered tectonite-type gold ore deposits by 3D synthetic modelling. We then collected real data of the Sizhuang gold deposit using the 3D distributed DC/IP method. The resistivity model obtained of this region is generally consistent with the known geological setting. Moreover, to obtain the information about the southern extension of the Jiaojia gold metallogenic belt, we conducted a 3D distributed DC/IP experiment in the Shijia area in the southern segment of the Jiaojia fault. The southern extension of the Jiaojia fault and tectonic evolution of shallow magma in this region were inferred from the 3D resistivity and chargeability models. Based on all the information above, we concluded that the 3D distributed DC/IP method has the advantages of 3D observations, high spatial resolution and great detection depth and will be one of the most effective methods for detecting altered tectonite-type gold ore deposits.

4

Inversion of side scan sonar motion and posture in seabed geomorphology

Tao W., Liu Y., Hu H.

Polish Maritime Research

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2017

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S 2

81--88

EN

Side scan sonar measurement platform, affected by underwater environment and its own motion precision, inevitably has posture and motion disturbance, which greatly affects accuracy of geomorphic image formation. It is difficult to sensitively and accurately capture these underwater disturbances by relying on auxiliary navigation devices. In this paper, we propose a method to invert motion and posture information of the measurement platform by using the matching relation between the strip images. The inversion algorithm is the key link in the image mosaic frame of side scan sonar, and the acquired motion posture information can effectively improve seabed topography and plotting accuracy and stability. In this paper, we first analyze influence of platform motion and posture on side scan sonar mapping, and establish the correlation model between motion, posture information and strip image matching information. Then, based on the model, a reverse neural network is established. Based on input, output of neural network, design of and test data set, a motion posture inversion mechanism based on strip image matching information is established. Accuracy and validity of the algorithm are verified by the experimental results.

5

Effect of water flows on ship traffic in narrow water channels based on cellular automata

Hu H., Chen X., Sun Z.

Polish Maritime Research

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2017

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S 3

130--135

EN

In narrow water channels, ship traffic may be affected by water flows and ship interactions. Studying their effects can help maritime authorities to establish appropriate management strategies. In this study, a two-lane cellular automation model is proposed. Further, the behavior of ship traffic is analyzed by setting different water flow velocities and considering ship interactions. Numerical experiment results show that the ship traffic density-flux relation is significantly different from the results obtained by classical models. Furthermore, due to ship interactions, the ship lane-change rate is influenced by the water flow to a certain degree.

6

The electrical resistivity signature of a fault controlling gold mineralization and the implications for Mesozoic mineralization: a case study from the Jiaojia Fault, eastern China

Zhang K., Lü Q., Yan J., Hu H, Fu G.

Acta Geophysica

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2017

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Vol. 65, no. 4

727--741

EN

We use 3D audio magnetotelluric method to the south segment of Jiaojia fault belt, and obtain the 3D electrical model of this area. Regional geophysical data were combined in an analysis of strata and major structural distribution in the study area, and included the southern segment of the Jiaojia fault zone transformed into two fault assemblages. Together with the previous studies of the ore-controlling action of the Jiaojia fault belt and deposit characteristics, the two faults are considered to be favorable metallogenic provinces, because some important features coupled with them, such as the subordinate fault intersection zone and several fault assemblages in one fault zone. It was also suggested the control action of later fault with reversed downthrows to the ore distribution. These studies have enabled us to predict the presence of two likely target regions of mineralization, and are prospecting breakthrough in the southern section of Jiaojia in the Shandong Peninsula, China.

7

The synergistic effect of boric acid and ammonium polyphosphate on the thermal degradation and flammability of pine-needles

Li L., Hu H., Guo C., Hu H.

Drewno : prace naukowe, doniesienia, komunikaty

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2014

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vol. 57, nr 193

37--49

EN

The synergistic effect of ammonium polyphosphate (APP) and boric acid (BA) on the flame retardancy and thermal degradation of pine needles was investigated. Thermogravimetric analysis (TGA) showed that the presence of an ammonium polyphosphate and boric acid system increased the char residue and decreased the pyrolysis temperature of the pine needles. The derivative thermogravimetric analysis (DTG) showed that the ammonium polyphosphate and boric acid had shifted the degradation peaks of the pine needles to lower temperatures. The cone calorimetry test results showed that the values of HRR, THR, SPR, TSP and the mass loss (%) of the pine needles treated with ammonium polyphosphate and boric acid (APP/BA = 3/2) were significantly lower than the other samples. Therefore, the APP and BA system had a better effect on the pine needles overall than the APP alone.

8

Impacts of vegetation type on soil phosphorus availability and fractions near the alpine timberline of the Tibetan Plateau

Zhang L., Wu Y., Wu N., Luo P., Liu L., Hu H.

Polish Journal of Ecology

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2011

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Vol. 59, nr 2

307-316

EN

Soil phosphorus (P) availability and fractions are influenced to a large extent by land use and cover changes. Inorganic P (IP) and organic P (OP) fractions in surface soils (0-20 cm) under typical vegetation types, including subalpine coniferous forests, alpine shrubs, and alpine shrub-meadows, near the alpine timberline of the eastern Tibetan Plateau of China, were measured by a modified Hedley fraction method. The results showed that OP is the dominant soil P fraction and the main source of available P in alpine soils near the timberline. Soil organic carbon, total nitrogen, and total P contents were higher in subalpine coniferous forests than in alpine shrubs and alpine shrub-meadows. Concentrations of soil labile P (the sums of Resin-IP, NaHCO3-IP, and NaHCO3-OP) were higher in subalpine coniferous forests than in alpine shrubs and alpine shrub-meadows, an observation that may be partially ascribed to the presence of deep litter layers generated by trees. Concentrations of soil labile and moderately organic P (NaHCO3-OP and NaOH-OP) in subalpine coniferous forests were also greater than in alpine shrubs and alpine shrub-meadows. Greater amounts of soil stable OP (extracted by concentrated HCl and cHCl.OP) were accumulated in alpine shrub-meadows compared to alpine shrubs or subalpine coniferous forests. The reduced availability of OP may be attributed mainly to increasing recalcitrant soil organic matter input in alpine shrub-meadows and alpine shrubs. Concentrations of IP associated with Ca minerals and parent materials (extracted by diluted HCl and HCl-IP, and extracted by concentrated HCl and cHCl-IP, respectively) were lower in subalpine coniferous forests, indicating that coniferous forests are more likely to use recalcitrant IP than alpine shrubs and alpine shrub-meadows. In this alpine region, land cover changes from subalpine coniferous forests to alpine shrubs and alpine shrub-meadows near the alpine timberline could decrease soil P conservation, availability, and supplementation.

9

Tearing properties of coated multi-axial warp knitted fabric

Hu H., Xu Y.

Autex Research Journal

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2008

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Vol. 8, no. 1

13--16

EN

In this paper, the tearing properties of a multi-axial warp knitted fabric produced with glass filaments and coated with PVC resin are presented. The typical tearing load-extension curves and influences of the different tearing testing conditions are analyzed. The results show that the tearing properties of the coated multi-axial warp fabric are different from those of the coated woven fabrics and that they depend on the tearing directions and tearing methods. The trapezoidal method and tearing tests along diagonal directions give higher resistance against tearing propagation.

10

Risk forecast of spontaneous combustion of sulfide ore dump in a stope and controlling approaches of the fire

Wu C., Li Z., Yang F., Hu H., Gu D.

Archives of Mining Sciences

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2008

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Vol. 53, no 4

565-579

EN

In this paper, a set of reliable devices and flowchart used for testing the potential of spontaneous combustion of sulfide ores (SOSC) are presented. An effective assessment method which depends upon the fire index system for evaluating the risk of SOSC in amining stope is introduced. To get more detailed information on self-heating situation in the ore dump at various period, the surface temperature on the ore dump is measured by an infra image apparatus and the temperature in the ore dump is analyzed both by ANSYS and FLUENT software. These results are visual and effective for applying correct measures for preventing the fire-breeding. Also, a group of chemical agents for abating the oxidized velocity are invented and can be sprayed into the ore dump. By integrating with all technical approaches described in above and using them for dealing with various practical conditions, the risk of SOSC in a stope can be effectively controlled.

PL

W niniejszym referacie, opisane zostały niezawodne urządzenia oraz schematy działań służące do badania potencjalnego samozapalenia się rudy siarczanu (SOSC). Przedstawiona została skuteczna metoda oceny służąca oszacowaniu ryzyka SOS C w przodku, która zależy od systemu wskaźnika pożarowości. Aby uzyskać bardziej szczegółowe informacje dotyczące samoogrzewania się hałdy rudy w różnych okresach, temperatura powierzchniowa na hałdzie mierzona jest za pomocą przyrządu na podczerwień, natomiast temperatura wewnątrz hałdy analizowana jest przy użyciu oprogramowania typu ANSYS oraz FLUENT. Wyniki tych badań są widoczne i użyteczne w celu zastosowania odpowiednich środków zapobiegających powstawaniu ognia. Wynalezione również zostały środki chemiczne służące spowolnieniu procesu utleniania, które mogą zostać rozpylone po powierzchni hałdy. Połączenie oraz praktyczne wykorzystanie wszystkich wyżej opisanych metod, może zapewnić efektywne kontrolowanie ryzyka samoistnego zapalenia się rudy siarczanu w przodku.

11

Formability of weft-knitted fabrics on a hemisphere

Zhong T., Hu H.

Autex Research Journal

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2007

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Vol. 7, no. 4

245--251

EN

In this paper, the formability of weft-knitted fabrics produced with glass filaments on an electronic flat knitting machine is experimentally investigated. A simple method used for the analysis of formability is proposed. Cutting patterns for different structures are given and the variation trends of the areas and fiber volume fractions are analyzed. The results show that due to their loop structures weft-knitted structures can easily be deformed to fit a hemisphere surface without the formation of wrinkling.

12

An experimental investigation into the radial compressive properties of the biodegradable braided regeneration conduits for peripheral nerve repair

Liu G., Hu H., Zhang P., Wang W.

Autex Research Journal

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2005

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Vol. 5, no. 2

106--112

EN

Different regeneration conduits braided from biodegradable material poly (glycolide-co-L-lactide) (PGLA) for peripheral nerve repair and their radial compressive properties are presented. The influences of the braided structure and braiding angle are discussed. The results have shown that the nerve conduit braided with the triaxial structure at 60 degrees of the braiding angle has a greater ability to resist radial compression.

13

A study of the degree of breakage of glass filament yarns during the weft knitting process

Hu H., Zhu M.

Autex Research Journal

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2005

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Vol. 5, no. 3

141--148

EN

In this paper, the degree of breakage of glass filament yarns during the weft knitting process is studied. A quantitative method used for assessing the degree of glass filament breakage is proposed, and the effects of different factors such as cam setting, knitted structures and yarn parameters are analysed. The experimental results show that an optimum cam setting exists at which the degree of filament breakage is minimum.