Rapid excavation with a newly developed retaining system: Spiral assembly steel structure

The spiral assembly steel structure, a newly developed retaining wall for the rapid excavation of small-sized foundation pits in unsaturated soil, is presented. This new type of retaining structure is prefabricated in the factory and is assembled on site in the excavation of a pit. This retaining structure is composed of several prefabricated steel structural units, in which the adjacent steel structural units are joined with connectors. Each steel structural unit has one steel pipe in the radial direction and is welded to a single piece of steel plate. After full installation in situ, the retaining structure becomes a cylindrical steel structure. With the protection afforded by this new type of retaining structure, excavation work can be completed within 24 h to a depth up to 5 m. In order to verify the reliability and effectiveness of this new retaining structure, field construction tests were conducted in Beijing, China. The test construction was monitored. The monitoring program included measuring stress in the structure, lateral earth pressure, and lateral deformation of the surrounding soil. The monitoring data from the field test were compared with the theoretical results. The results show that the proposed new structure is reliable and effective.

Gas field construction on time

About one--fOurth of the con- sery’e capacity at l00 billion cubic me-struction on China’s largest off shore tres.drilling field is now complete. and en- By January 30. more than 240gineers say the projcct is on schedule kilo1netres ol’ underu:ater pipelinestbr opening January l. l996. u:ere laid. about one fourth of the to-The Ya l3-- l Gas Field in the ta1. according yesterday’s o\’erseas edi-South Chlna Sea wiIl suppl} Hong tion or People’s Dall}’.Kong and Hainan Province w’ith natu- Exentually tuo underuaterral gas. Estimates put the tield’s re- pipeIInes ’’iIl he constructedt one.

Sustainable micro-activation of dissolved oxygen driving pollutant conversion on Mo-enhanced zinc sulfide surface in natural conditions

The activation of inert oxygen(O_(2))often consumes enormous amounts of energy and resources,which is a global challenge in the field of environmental remediation and fuel cells.Organic pollutants are abundant in electrons and are promising alternative electron donors.Herein,we implement sustainable microactivation of dissolved oxygen(DO)by using the electrons and adsorption energy of pollutants by creating a nonequilibrium microsurface on nanoparticle-integrated molybdenum(Mo)lattice-doped zinc sulfide(ZnS)composites(MZS-1).Organic pollutants were quickly removed by DO microactivation in the MZS-1 system under natural conditions without any additional energy or electron donor.The turnover frequency(TOF,per Mo atom basis)is 5 orders of magnitude higher than those of homogeneous systems.Structural and electronic characterization technologies reveal the change in the crystalline phase(Zn-S-Mo)and the activation of π-electrons on six-membered rings of ZnS after Mo doping,which results in the formation of a nonequilibrium microsurface on MZS-1.This is the key for the strong interfacial interaction and directional electron transfer from pollutants to MZS-1 through the delocalized π-π conjugation effect and from MZS-1 to DO via Zn-S-Mo,as demonstrated by electron paramagnetic resonance(EPR)techniques and density functional theory(DFT)calculations.This process achieves the efficient use of pollutants and the low-energy activation of O_(2) through the construction of a nonequilibrium microsurface,which shows new significance for water treatment.