Analysis of Compression Resistance and Oil Adsorption Capacity of Cellulose/NaOH Cryogels

This work aimed at analyzing the petroleum adsorption capacity and the compressive strength of cellulose cryogels produced with the addition of 4 and 8%(w/w)sodium hydroxide(NaOH).Cryogels were produced from a 1.5%(m/m)suspension of cellulose microfibers,which originated from Pinus elliotti,in distilled water.The addition of NaOH increased the compression strength of cryogel by 30% when compared to cryogel without the reagent.Due to the 50% decrease in volume,the cryogel FLNB-8h(8%NaOH)has its petroleum adsorption capacity decreased in average by 58%,whereas the FLNB-4(4%NaOH)cryogel had it only by 14%.The cellulose suspension which provided the best results for the properties of the cryogels tested had a 4%concentration of NaOH.

Compression Sensibility of Magnetic-concentrated Fly Ash Mortar under Uniaxial Loading

The electrical conductivity, compression sensibility, workability and cost are factors that affect the application of conductive smart materials in civil structures. Consequently, the resistance and compression sensibility of magnetic-concentrated fly ash （MCFA） mortar were investigated using two electrode method, and the difference of compression sensibility between MCFA mortar and carbon fiber reinforced cement （CFRC） under uniaxial loading was studied. Factors affecting the compression sensibility of MCFA mortar, such as MCFA content, loading rate and stress cycles, were analyzed. Results show that fly ash with high content of Fe3O4 can be used to prepare conductive mortar since Fe3O4 is a kind of nonstoichiometric oxide and usually acts as semiconductor. MCFA mortar exhibits the same electrical conductivity to that of CFRC when the content of MCFA is more than 40% by weight of sample. The compression sensibility of mortar is improved with the increase of MCFA content and loading rate. The compression sensibility of MCFA mortar is reversible with the circling of loading. Results show that the application of MCFA in concrete not only provides excellent performances of electrical-functionality and workability, but also reduces the cost of conductive concrete.

Anti-JPEG Compression Steganography Based on the High Tense Region Locating Method

Robust data hiding techniques attempt to construct covert communication in a lossy public channel.Nowadays,the existing robust JPEG steganographic algorithms cannot overcome the side-information missing situation.Thus,this paper proposes a new robust JPEG steganographic algorithm based on the high tense region location method which needs no side-information of lossy channel.First,a tense region locating method is proposed based on the Harris-Laplacian feature point.Then,robust cover object generating processes are described.Last,the advanced embedding cost function is proposed.A series of experiments are conducted on various JPEG image sets and the results show that the proposed steganographic algorithm can resist JPEG compression efficiently with acceptable performance against steganalysis statistical detection libraries GFR(Gabor Filters Rich model)and DCTR(Discrete Cosine Transform Residual).

Influence of an emulsifier on the pressure desensitization of emulsion explosives

The desensitization degree of emulsion explosives （EE） was calculated with the peak pressure of explosion shock waves tested in water. To an explosive, the less the desensitization degree, the better the compression resistance, so the compression resistance of an explosive can be compared and analyzed quantificationally with the desensitization degree. The influence of an emulsifier on the pressure desensitization of EE was studied, including the content and category of emulsifiers. Three kinds of emulsifiers （Span-80, compound emulsifier, and T-152） were used in the tests. The experimental results show that both the content and category of emulsifiers make a great effect on the pressure desensitization of EE. The desensitization degree of EE reduces with the emulsifier content being increased, but there is an optimal content of an emulsifier for the compression resistance of EE. While the content of Span-80 reaches 4wt%, the desensitization degree of EE becomes a minimal value, and augments somewhat if the emulsifier content is increased more. That is to say, the compression resistance of EE becomes the highest while the content of Span-80 is 4wt%, and the compression resistance will decline if the content of Span-80 is increased more. The compression resistance of the explosive emulsified by compound emulsifier is the highest among all the explosives, when the content of the whole components and manufacturing engineering are kept invariable.

High-temperature performance study of chromium-containing stuffing sand for ladles

High-temperature performance tests of chromium-containing stuffing sand for a steel ladle w ith different ratios w ere performed. A high-temperature simulation test furnace w as used to analyze the influence of the composition ratio of ladle filler sand and sintering time on the high-temperature compression resistance of chromium-containing stuffing sand in the temperature range of 1 500- 1 600 ℃. The results show that the refractoriness of ladle filler sand w as the low est（ only 1 610 ℃） w hen the composition ratio of chromite sand and silica sand w as 6∶ 4. M oreover,the high-temperature compression resistance w as high w hen the content of chromite sand w as at 70%; the resistance increased w ith increasing sintering time. When the sintering time w as extended at a temperature of 1 600 ℃,the high-temperature compression resistance of ladle filler sand first increased and then decreased after being overburnt.

THE PROPERTIES OF SILICA FUME-MAGNESIUM OXYCHLORIDE CEMENT MATERIALS

The properties of a new magnesium Oxychloride cement (MOC) material formed by silica fume uniformly mix in MOC paste was presents. The influence of silica fume on the water resistance and compressive strength of MOC paste was invesigated in this study. It is shown that when 30 weight percent of silica fume is added to the MOC paste, a high strength and water resisting new material with 112MPa compressive strength and 1 00 water resisting coefficient could by obtained.

Effect of Compression on the Crystallization Behavior and Corrosion Resistance of Al_(86)Ni_9La_5 Amorphous Alloy

The effect of compression on the crystallization behavior and corrosion resistance of Al（86）Ni9La5 amorphous ribbons was investigated by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, scanning elec-tron microscopy （SEM） and electrochemistry test. The XRD and TEM results reveal that the compressed Al（86）Ni9La5 ribbons spun with the circumferential speed （R） of 29.3 m/s are in fully amorphous state; however, the compressed ribbons spun with R=14.7 m/s have crystalline phases embedded in the amorphous matrix. The SEM images indicate that after compression, the toughness of the ribbons increases. Electrochemical results show that the compression decreases the stability of the passive film of the Al（86）Ni9La5 amorphous ribbons, because of the compression-introduced free volume, shear bands and crystalline phases; meanwhile, with R=14.7 m/s, the compression-induced crystalline phases in the Al（86）Ni9La5 ribbons increase the corrosion potential.

Upper Bound Solution of the Resisting Moment Bearing Capacity of A Composite Bucket Shallow Foundation of An Offshore Wind Turbine in Sand

Bearing the large moment that is generated by the wind load that acts on the upper structure of offshore wind turbines is an important feature of their foundations that is different from other offshore structures.A composite bucket shallow foundation(CBSF)has been proposed by Tianjin University to address the soft geological conditions in the offshore regions of China for wind turbines.The CBSF is a new type of foundation and is effective against large moments.The soil deformation test of a CBSF and the numerical simulation study under the same working conditions are carried out to determine the failure mechanism of a CBSF under moment loading.The resisting soil compression rateηm is defined as a new empirical parameter that indicates the ability of the soil inside the bucket to resist moment loading.The upper limit of the resisting moment bearing capacity of the bucket foundation is derived through the upper bound theorem of classical plasticity theory based on the failure mechanism.The calculation method is validated by tests of bucket models with different height-diameter ratios in sand under moment loading.

Preparation,structure and mechanical properties of Sialon ceramics by transition metal-catalyzed nitriding reaction

Sialon ceramics were prepared by the nitridation of Si,Al and Al2O3 powders with the transition metals(Fe Co,Ni)catalysts.The phase composition,microstructure and mechanical properties of specimens were studied Compared with the catalyst-free specimen,the addition of Fe,Co and Ni greatly promoted the nitridation process of Sialon ceramics and improved the weight gain rate and mechanical properties of specimens.With the increased content of catalysts,the apparent porosity of the products decreased first and then increased,contrary to flexural strength and compressive strength.The specimen with 2.5 wt%Fe had the highest flexural strength 145.8 MPa and it exhibited the highest compressive strength of 594.6 MPa when Co content was 2.5 wt%,whereas they were 71.9 and 78.7 MPa,respectively,when without catalyst.