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In the pipeline construction, the girth welds tend to be the weakness because of defects and microstructural heterogeneities. The importance of suitable assessment of various defects in the weld is not only to prevent the cracks from unstable growth to cause catastrophic accident but also can effectively reduce the weld repair to reduce construction cost. Although many welding defects assessment methods and codes have been applied in this field, there are many differences among them. In this paper, the application of weld defect assessment methods was extensively studied. The key points of ECA applications, such as the pipeline axial stress and toughness, have been introduced. Furthermore, some suggestions were given on the application of girth weld ECA assessment.

Using the analysis techniques of polarizing optical microscope and electron probe, mineral composition, ore texture and structure and the occurrence of Au in the primary ore are studied. The research shows that the main ore minerals in the ore include realgar, pyrite and arsenopyrite etc. Sulfur-stibarsen is the main carrier of Au, and is the major associated mineral of realgar, surrounded mainly by realgar, and partly is the associated mineral of arsenopyrite. The existence of visible gold and microscopic gold in the ore of this mining area can be excluded, and the gold might exist mainly in the form of inclusion gold, which is the so-called “nanoAu”.

MnxZn1-XO Crystal was synthesized by hydrothermal method in this work.The experimental parameters for hydrothermal synyhesis were:Mineralizer concentration 3mol•L-1KOH, the fill factor 35%, temperature 430°C, Zn(OH)2 doped with MnO2 as precursor, and the reaction time 24 hours. The Mn concentration in crystal was determined by X-ray EDS. The atomic percentage of Mn in crystal increases as the concentration of MnO2 in precursor increased. The maximum atomic percentage for Mn is over 2%. The morphology shows characteristics of hexagonal prism of pure ZnO crystal. The exposed faces are hexagonal faces m｛10 0｝, hexagonal cone faces p｛10 1｝, negative polar faces ｛000 ｝and positive polar faces｛0001}. The diameters of the crystals are 50-200μm，the heights are 20-100μm.

A new technique, direct photodegradation of self-assembled monolayers (SAM), to obtain surface energy gradients on Si substrates was demonstrated. The gradient surface, with hydrophobic to hydrophilic gradients, was prepared by two steps: Firstly, a homogeneous fluoroalkylsilane SAM film was deposited by a chemical vapor deposition on a Si substrate. Secondly, a controlled photodegradation technique was directly applied to the homogeneous FAS-SAM surface. The surface energy gradient was then obtained due to the different intensity of photoirradiation in the different positions along the photodegraded path on the SAM surfaces. The resulting surface displayed a gradient of wettability (with the contact angle of water changing from 55° to 18°) over a distance of 4.2 mm. The water droplet was driven by surface energy gradient and spontaneously moved from the hydrophobic to hydrophilic surface. During the moving process, the water droplet accelerated firstly and then decelerated. The peak velocity was about 23.3 mm/s. The velocity is dependent on the gradient of the surface energy.

A surface with surface energy gradient was fabricated by using a controlled photodegradation technique of a fluoroalkylsilane self-assembled monolayer (SAM) using irradiation of vacuum ultraviolet light (wavelength=172 nm). Visualization experiments were carried out to investigate the motion behaviors of water droplets on horizontal gradient surfaces. System free energy conversion was analyzed to understand the mechanics of the droplet self-motion. The results show that the liquid droplets were self-propelled to move from hydrophobic region to hydrophilic region on horizontal gradient surfaces. The motion process of the water droplet experienced an accelerating stage and a decelerating stage. The velocity of 2 mL water droplet reached to a maximum of 23.28 mm/s. In the droplet motion on the horizontal gradient surface, the deformation and spread of the droplet continuously release out the interfacial and gravitational potential energy, which offers the kinetic energy for the droplet motion. However, the released interfacial energy is three orders of magnitude larger than the released gravitational potential energy. Thus, the released interfacial energy is the main source of driven energy for the droplet motion. The theoretical analysis is consistent with the experimental results.

Theoretical calculations suggest that creating superoleophobic surfaces would require a surface energy lower than that of any known materials. In the present work, we demonstrate micronanostructured ZnO-based surfaces displaying apparent contact angles (CA) greater than 150, even with hexadecane (surface tension l = 27.5 mN/m). The specific ZnO microtextures were fabricated by a chemical solution method, and fluoroalkylsilane (FAS) was then used to tune the surface wettability. The combination of ZnO microtextures and FAS modification resulted in a superoleophobicity with CA for hexadecane was 154.6 (161.9 for diethylene glycol (l = 45.2 mN/m). This apparent superoleophobic behavior was induced on intrinsically oleophilic materials mainly by topography (i.e. the specific ZnO microtextures), which form a composite surface of air and solid with oil drop sitting partially on air. Such special wetting state is a metastable Cassie state. The results are expected to promote the study on self-cleaning applications, especially in the condition with oil contaminations.

Superhydrophobic surfaces, which have anti-adhesion and self-cleaning properties, were fabricated on Al substrates. The self-cleaning surface was prepared by two steps: firstly, a chemical solution method was used to create the surface roughness with disorderly veins micronanostructures. Secondly, fluoroalkylsilane was deposited on the rough surface to lower its surface energy. The combination of veins micronanostructures and fluoroalkylsilane modification gave the surface a superhydrophobicity with static water contact angle of 166° and sliding angle of smaller than 1°. Additionally, the surface showed a strong anti-adhesion with water and a satisfied self-cleaning property. Water droplets easily rolled off the surface and picked up dirt and debris with them. The surfaces obviously corresponded to Cassie (not Wenzel) -model. Air entrapped within the veins microstructures greatly increases the air/water interface, effectively preventing the penetration of water into the grooves, and finally exhibiting the self-cleaning property. The results will greatly extend Al substrates for specific functions such as water-repellence, self-cleaning and anti-fouling.

Superhydrophobic ZnO films were prepared by a simple low-temperature solution method, where the ZnO morphology was tuned by hydrofluoric acid. The film topography presents two different length scales: micro flower-like-spheres and nano petals. Such hierarchical structures give the film a superhydrophobic behavior with water contact angle (CA) of 151°, turning into a superhydrophilic one (CA < 5°) after 30 min vacuum ultraviolet (VUV) illumination. The transition from superhydrophobicity to superhydrophilicity is more quickly than the past report using UV illumination because VUV gives higher energy upon the ZnO films. The VUV-illuminated film can be recovered to superhydrophobic through being placed in the dark. Such special wettability can be explained based on ZnO as a photoinduced semiconductor and a photocatalyst. This study will greatly extend applications of ZnO nanomaterials to many important fields, such as microfluidic devices.