Green Low-Carbon High-Density Urban Center Planning Wuhan Wangjiadun Area

2021 ◽  
pp. 159-177
Author(s):  
Shen Xu
Keyword(s):  
High Density ◽  
Low Carbon ◽  
Urban Center

Selective Laser Melting of Prealloyed High Alloy Steel Powder Beds

2006 ◽  
Vol 514-516 ◽  
pp. 516-523 ◽  
Author(s):  
C. Steven Wright ◽  
M. Youseffi ◽  
S.P. Akhtar ◽  
T.H.C. Childs ◽  
C. Hauser ◽  
...  
Keyword(s):  
Selective Laser Melting ◽  
Nd:Yag Laser ◽  
Continuous Wave ◽  
Single Layer ◽  
Steel Powder ◽  
High Density ◽  
Powder Particle Size ◽  
Low Carbon ◽  
Laser Melting ◽  
High Alloy

This paper presents the results of a recent comprehensive investigation of selective laser melting (slm) of prealloyed gas and water atomised M2 and H13 tool steel powders. The objective of the study was to establish the parameters that control the densification of single and multiple layers with the aim of producing high density parts without the need for infiltration. Powders were processed using continuous wave (CW) CO2 and Nd:YAG lasers. Relationships between alloy composition, powder particle size and shape, flowability, microstructure (phases present, their size, morphology and distribution), track morphology, post scanned density, surface finish and scan conditions (Laser power, spot size and scan speed) are discussed for single track, single layer and multi-layer (up to 25 layers) constructions. Processing with a Nd:YAG laser with powders placed on substrates rather than on a loose powder bed gave more stable builds than with the CO2 laser. Using the Nd:YAG laser densities up to ~90% relative were possible with H13 powder compared with a maximum of ~70% for M2 in multi-layer builds. Maximum density achieved with CW CO2 processing was only ~60%, irrespective of powder composition. The paper compares the processibility of these materials with stainless steel powders processed to higher densities (up to 99% relative) under similar conditions. The results of the work show that a crucial factor for high density processing is melt pool wettability and this is controlled largely by carbon content; low carbon contents producing better wettability, flatter tracks and higher densities. The significance of this observation for the processing high alloy steels by slm will be discussed.

Study on Low-Carbon Transportation Plan in China

2012 ◽  
Vol 598 ◽  
pp. 121-124 ◽  
Author(s):  
Hong Xiao
Keyword(s):  
Urban Planning ◽  
Large Population ◽  
High Density ◽  
Low Carbon ◽  
Urban Problems ◽  
Centralization And Decentralization ◽  
Transportation Plan

The urban motorization has enhanced along with economy development in China, but the environment question and the energy question which brings by the transportation is more serious on urban , I analyzed urban problems along with high density construction by large population, and put forward that the key to low-carbon urban planning under the motorized issues is to deal with relationships between centralization and decentralization .

Concurrent Load Design Criteria for Buried High Density Polyethylene Pipe in ASME BPVC Section III, Division 1, Applications: Part III — Sample Problem

2007 ◽  
Author(s):  
George G. Thomas ◽  
Jack R. Spanner ◽  
Timothy M. Adams ◽  
Siegrid Hall
Keyword(s):  
High Density Polyethylene ◽  
Nuclear Power ◽  
Low Carbon Steel ◽  
The United States ◽  
High Density ◽  
Design Criteria ◽  
Low Carbon ◽  
Service Water ◽  
Water Reactors ◽  
Water Piping

The commercial Light Water Reactors operating within the United States have been in service from about 20 to 35 years. These plants include buried Service Water piping systems primarily made from low carbon steel. This piping has been subject to aging over the years, resulting in degradation and corrosion that will require replacement of the piping. Due to the advantageous cost and durability of High Density Polyethylene (HDPE) piping (as demonstrated in other commercial industries), the industry has expressed interest in replacing steel buried Service Water Piping in Nuclear Power Stations with HDPE piping. To assist in this effort EPRI has funded and supported the work summarized in this paper to develop design criteria for HPDE Pipe. This paper provides an example problem demonstrating the application of recently developed design criteria for HDPE piping. The technical bases of these criteria are presented in separate papers and are not repeated in this discussion.

NITROGEN AND CARBON SATURATION KINETICS OF POWDERED MATERIALS OBTAINED BY HOT STAMPING IN THE PRODUCTION OF COMPLEX FORM PARTS

2020 ◽  
Author(s):  
N.G. Prous ◽  
◽  
M.S Egorov ◽  
V.V. Sukhomlinova
Keyword(s):  
Diffusion Layer ◽  
Hot Stamping ◽  
Complex Form ◽  
Treatment Temperature ◽  
High Density ◽  
Powder Materials ◽  
Low Carbon ◽  
The Difference ◽  
Increasing Temperature ◽  
Kinetics Of

The processes occurring at saturation of the surface with various elannotation The paper deals with issues related to the kinetics of saturation of high-density powder materials obtained by hot stamping (GS). The effect of surface treatment, temperature and time of saturation of the surface of highdensity powder materials with nitrogen and carbon is investigated. The graphs of the influence of these factors are given. The structures of the diffusion layer and the effect of the surface features of high-density powder materials on saturation with nitrogen and carbon are described. Comparative studies on the saturation of the surface layer at the SC of high-density powder materials and rolled steels have been carried out. It is established that the thickness of the diffusion layer on the iron powder is greater than that on low-carbon electrical steel and the magnitude of the difference slightly decreases with increasing temperature.

Research on the Low-Carbon Land Use Pattern

2012 ◽  
Vol 598 ◽  
pp. 241-246
Author(s):  
Ya Li Luo ◽  
Chang Xin Zhang
Keyword(s):  
Land Use ◽  
Carbon Emissions ◽  
High Density ◽  
Low Carbon ◽  
Land Use Pattern ◽  
Mixed Use ◽  
Use Pattern ◽  
The City

The paper firstly analyzed the carbon emissions effect of the city land use. Then it put forward the high density compact land use pattern is consistent with low-carbon developing goal. Finally, the paper systematically expounded the connotation of the low-carbon high density compact mixed use, and discussed the basic forms of low-carbon land use pattern, such as the giant single building, buildings on the same platform, new units model on the community scale etc..

Seismic and Concurrent Load Design Criteria for Buried High Density Polyethylene Pipe in ASME BPVC Section III, Division 1, Applications: Part I — Piping Design Basis Criteria

2007 ◽  
Author(s):  
Timothy M. Adams ◽  
Jack Spanner ◽  
Rudolph J. Scavuzzo ◽  
George Gary Thomas
Keyword(s):  
High Density Polyethylene ◽  
The United States ◽  
High Density ◽  
Design Criteria ◽  
Low Carbon ◽  
Modes Of Failure ◽  
Service Water ◽  
Hdpe Pipe ◽  
Asme Code ◽  
Water Piping

The commercial Light Water Reactors operating within the United States have been in service from about 20 to 35 years. These plants include buried Service Water piping systems primarily made from low carbon steel. This piping has been subject to aging over the years, resulting in degradation and corrosion that will require replacement of the piping. Due to the advantageous cost and durability of High Density Polyethylene (HDPE) piping (as demonstrated in other commercial industries), ASME code inclusion of this piping is logical. Duke Power industry has expressed interest in replacing a portion of their steel buried Service Water Piping in Nuclear Power Stations with HDPE pipe. To assist in this effort EPRI has funded and supported the work summarized in this paper to develop design criteria for HPDE Pipe and has teamed with EPRI to develop appropriate ASME Code requirements. Other nuclear utilities will follow once HDPE piping is included in the ASME Code. This paper includes proposed allowable limits of all modes of failure and provides design criteria for HDPE pipe made from PE 3408 resin. It also provides the technical basis for the proposed criteria. This paper deals primarily with the actual design of the piping. The methods included comply with ASME Power Piping Code, B31.1-2004 and Section III of the ASME Boiler and Pressure Vessel Code. Extensive use was made of industrial research, data and experience over 40 years of use of high-density polyethylene piping. Allowable stresses are based on data published in these sources for Design and Service Levels A-D.

Association between Tree Pollen Counts and Asthma ED Visits in a High-Density Urban Center

2011 ◽  
Vol 48 (5) ◽  
pp. 442-448 ◽  
Author(s):  
Sunit P. Jariwala ◽  
Satya Kurada ◽  
Heather Moday ◽  
Andy Thanjan ◽  
Laurel Bastone ◽  
...  
Keyword(s):  
High Density ◽  
Urban Center ◽  
Tree Pollen ◽  
Pollen Counts ◽  
Ed Visits

S.E.M.-T.E.M. Image Comparison

1971 ◽  
Vol 29 ◽  
pp. 132-133
Author(s):  
G. M. Greene ◽  
J. W. Sprys
Keyword(s):  
Electron Microscope ◽  
Low Carbon Steel ◽  
Secondary Emission ◽  
Low Carbon ◽  
Preparation Time ◽  
Actual Surface ◽  
Fine Detail ◽  
Transmission Electron ◽  
Transmission Study ◽  
Large Sections

The present study demonstrates that fracture surfaces appear strikingly different when observed in the transmission electron microscope by replication and in the scanning electron microscope by backscattering and secondary emission. It is important to know what form these differences take because of the limitations of each instrument. Replication is useful for study of surfaces too large for insertion into the S.E.M. and for resolution of fine detail at high magnification with the T.E.M. Scanning microscopy reduces sample preparation time and allows large sections of the actual surface to be viewed.In the present investigation various modes of the S.E.M. along with the transmission mode in the T.E.M. were used to study one area of a fatigue surface of a low carbon steel. Following transmission study of a platinum carbon replica in the T.E.M. and S.E.M. the replica was coated with a gold layer approximately 200A° in thickness to improve electron emission.

Sign in / Sign up

Export Citation Format

Share Document