Experiment on Mode Ⅰ/Ⅱ Mixed Interfacial Fracture Characterization of Foam Core Sandwich Materials at Elevated Temperatures

Foam-cored sandwich materials have been widely used in the civil engineering due to their advantages such as lightweight,high strength,and excellent anti-corrosion ability. However,the interfacial bonding strength of foamcored sandwich materials is weakened at elevated temperatures. In practice,the effect of high temperature cannot be ignored,because the composites and foams are sensitive to the change of temperature in the environment. In this study,a series of single-leg bending beams were tested at different temperatures to evaluate the influences of high temperatures on Mode Ⅰ/Ⅱ mixed interfacial fracture of foam core sandwich materials. The temperature was from29 ℃ to 90 ℃,covered the glass transition temperature of composites and foam core,respectively. The Mode Ⅰ/Ⅱ mixed interfacial crack prorogation and its corresponding interfacial strain energy release rate were summarized.

Model Test Research of Breakwater Core Material Influence on Wave Propagation

The interaction between waves and porous breakwater has an important theoretical significance and great application value of engineering.In this paper,the tests of the core material's influence in rubble mound breakwater on wave propagation are carried out.The relations among the transmitted wave height,incident wave element,and breakwater width are discussed.The calculation formula is obtained.The test results show that different core materials have obvious influence on wave propagation.

Development of Glass Optical Fibers 1970-2020,Providing Us the Digitalized Communication World

New types of communication cables were found to be needed already during the 1960-decade,because the copper cables had,and still would have,too high attenuation and especially limited bandwidth,due to extremely high dispersion at communication signals above 2 Mbit/s.Already the first commercially available multimode optical fibers(1979),developed from pure silica glass with a Ge-doped core,had much lower attenuation at signal frequencies of the order of 2-9 Mbit/s and above it.However,fiber core,cladding and coating materials,cable structures and materials,as well as manufacturing-,measurements-and test methods have been needed to be developed much further to get the reliable fiber cable communication networks.The important development stages and solutions to the most significant childhood problems of the optical fibers and cables are described in this paper.Now over 500 million km of optical fibers are manufactured and installed worldwide for the communication networks.The understanding of how to make the fibers with the very good transmission,mechanical and reliability properties exists at the manufacturers of the fibers and cables.

Encapsulation in the Food Industry: A Brief Historical Overview to Recent Developments

Encapsulation in food industry serves several functions including masking of undesirable color/flavor/taste, preservation of unstable constituents, incorporation of additional functional and nutritional components and site-specific release of encapsulated ingredients at a controlled time and rate. The knowledge of microencapsulation in other sectors like pharmaceutical industry is well advanced;however, more understanding is required to harvest the maximum benefits from food industry. This paper started with highlighting the gradual progress of microencapsulation process in food industry and ended up with some invaluable suggestions for future works. In the body, the paper reviews the major techniques of food encapsulation, choices of coating materials and the performance measurement methods of food encapsulation. Future trends, scopes and aspects of microencapsulation process in food manufacturing sector are also presented as the necessary recommendations for future researches. The article would help the microencapsulated food manufacturers to choose the target oriented encapsulates and suitable encapsulation technique.

A Review of Test Methods for the Determination of the Permeability Coefficient of Gravelly Soils Used for Embankment Dams

The factors influencing the permeability coefficient of gravelly soils used for the development of embankment dams(core wall)are analyzed.Such factors include(but are not limited to)soil size,anisotropy,density and boundary effects.A review of the literature is conducted and new directions of research are proposed.In such a framework,it is shown that gravelly soil with controlled density and vertical stress should be used to optimize the measurement of the vertical and horizontal permeability coefficients,respectively.

Preparation and Properties of a Novel Water Soluble Core Material

A novel water-soluble core material composed of polyethylene glycol,sodium chloride,mica powder and plasticizer was prepared.The compressive strength,bend strength,hygroscopic coefficient and the material solubility in water were investigated.The results show that the compressive yield strength of the soluble core can reach 1 MPa and the highest compressive strength can reach 4 MPa,the bend strength is as high as 6.65 MPa,the hygroscopic coefficient is lower than 0.22%/month and the solubility of suitable core material is 35.7-55.75 g/（min·m 2）.The wax pattern with undercuts was prepared successfully by using the novel water-soluble core material.

Manufacture of Light-weight Composite Panel from Kenaf

Light-weight composite panels were manufactured using kenaf core particles as core material and kenaf bast fiber-woven sheets as top and bottom surfaces. Methylene diphenyldiisocyanate (MDI) resin was used as the adhesive with the resin content of 4% for core particles and 50 g/m2 for bast fiber- woven sheets. The target board densities were set at 0.35, 0.45 and 0.55 g/cm3. The composite panels were evaluated with Japanese Industrial Standard for Particleboards (JIS A 5908- 2003).The results show that the composite panel has high modulus of rupture and internal bonding strength. The properties of 0.45 g/cm3 density composite panel are: MOR 20.4 MPa, MOE 1.94 MPa, IB 0.36 MPa, WA142%, TS 21%. Kenaf is a good raw material for making light-weight composite panels.