Corrosion performance of Al–Al2O3 cold sprayed coatings on mild carbon steel pipe under thermal insulation

This paper focused on the corrosion resistance of cold spray Al–Al_2O_3composite coatings used on carbon steel pipe surfaces under thermal insulation. Al–Al_2O_3coatings were produced on the carbon steel pipe surface by cold spray(CS) technology. Experimental apparatus was built to test the corrosion resistance of coatings beneath mineral wool insulation under isothermal, thermal cycling and wet/dry conditions. The results showed that when α-Al_2O_3 was added in spraying powder, the coating could obtain higher hardness and a denser microstructure. From corrosionunder-insulation(CUI) tests, Al–Al_2O_3CS coatings were proven to be efficient in protecting carbon steel pipe from CUI mainly owning to lamellar microstructures of coatings. There was no evidence to show that α-Al_2O_3 might bring any negative effect on corrosion resistance. Al–Al_2O_3CS coatings were sensitive to the chloride ion concentration. When these coatings were exposed to higher concentrations of NaC l, the coating's exhibited faster degradation.

Effect of TiO_2 content on properties of Al_2O_3 thermal barrier coatings by plasma spraying

Al2O3 thermal barrier coatings with different TiO2 contents were deposited on 6061 aluminum alloy by plasma spraying. The corrosion resistance, thermal insulation property and phase composition of these coatings were investigated. The results indicate that all the feedstock powders exhibit phase transformation during the spray process. With the increase of the TiO2 content in the powder, the corrosion resistance of the coating is enhanced but the thermal insulation property is decreased. This can be attributed to the higher thermal conductivity but lower melting point and brittleness of TiO2 than those of Al2O3, so it is easy for TiO2 to disperse in the brittle Al2O3 substrate during spraying, in which these dispersively distributed TiO2 play the role of hole sealing, releasing stress and reducing cracks.

Techniques to Reduce the Energy Consumption in Building in Hot Arid Rejoin （Iraq）

The Iraqi climate is extremely hot and arid zone covers a belt between latitude （29°N to 36°N）. The energy required for air conditioning of Iraqi buildings is about 60% of the entire energy consumption in buildings. This research deals with the possibility of using different technics for the reducing energy consumption in buildings by blocking or eliminates the effect of direct solar radiation in summer season. This study deals with different local insulation materials which were added to the south face of walls surface of Iraqi buildings, as well as built water spray system upon the exterior roof surface to minimize the effect of incident solar radiation upon the roofs and wall surfaces. The results showed that thermal conductivity of local insulation materials （papyrus） are very low, also the results showed that when using water spray roof system, gives good indication to use this method in hot arid rejoins.

Transient performance and intelligent combination control of a novel spray cooling loop system

Effective thermal control systems are essential for the reliable working of insulated gate bipolar transistors （IGBTs） in many applications. A novel spray cooling loop system with integrated sintered porous copper wick （SCLS-SPC） is proposed to meet the requirements of higher device level heat fluxes and the harsh environments in some applications such as hybrid, fuel cell vehicles and aerospace. Fuzzy logic and proportional-integral-derivative （PID） policies are applied to adjust the electronic temperature within a safe working range. To evaluate the thermal control effect, a mathematical model of a 4-node thermal network and pump are established for predicting the dynamics of the SCLS-SPC. Moreover, the transient response of the 4 nodes and vapor mass flowrate under no control, PID and Fuzzy-PID are numerically investigated and discussed in detail.

A CARBON CLOUD WITH PLATINUM LINING

Picture this.On a freezing December day,a few days before Christmas,2008 an electrical fire started in the base­ment utility room.The burn damage was so severe at the origin site that the exact cause could not be determined,but the theory is that a transfer switch connected to an emergency power generator started the fire when an auto test series was initiated.The fire quickly spread to the ceiling of the basement utility room,which was not fire rated,and burned the floor out of the kitchen above,at the center of the two-story home.In a very short time,the kitchen col­lapsed into the basement.The fire began shortly after the five family mem­bers left for work and school and was discovered by a worker who arrived to complete a bathroom remodel.Thick black smoke poured through every vent to the outside.By the time firefighters gained control of the blaze,the 3,000-sq-ft house and everything in it was ruined.If this image conjures a big black carbon cloud for you,imagine what the family was going through.Everything they owned was burned or covered with black soot and ice.It was a devastating blow to a smart young family going about their daily lives.It was the epitome of a dark cloud,and a silver lining seemed only like a myth.About the same time,a group of local tradesmen called the Hamptons Green Alliance(HGA),who organized a few months earlier,were busy soliciting local architects.Through the AIA Peconic,the HGA sent an e-mail blast to all members in order to find a project they could initiate in order to exercise their old and new sustainable building skills.Their goals were to apply their cumulative knowledge and expertise in sustainable practices and integrate them into a sum greater than the parts.Each individual company had experience,but never before had they consciously col­laborated on a design that integrated all their systems at once.All would share the benefit and help the HGA raise the bar on sustainable building so they could offer experience,expertise,and specific energy usage and production data,including life cycle analysis,to future clients.They offered their services at their cost,to any architect’s client interested in a new house or remodel that would be rebuilt with the highest and best sustainable practices possible.At the peak of the financial panic,AIA members found no takers.Richard(Ric)Stott,AIA LEED AP,architect,was a friend of the fire-struck family and of course offered help.After the first meeting with another family friend and architect Craig Lee,AIA,it struck Ric that this would be the perfect project for the Hamptons Green Alliance.The owner agreed,a meeting was scheduled,and a project involv­ing all major trades,the architects,owners,and even the insurance adjusters was born.It was not hard for Ric to convince the team that the LEED for Homes program would be appropriate for this project and soon the team began meeting once a week to focus on goals,discuss strategy,and learn about the requirements of the LEED for Homes system.By default,it was an“Integrated Project Delivery”(IPD).All the team members were in play from the beginning,the budget was fixed at what the insurance claim paid,plus the owners’out-of-pocket expense to add a family room and bedroom.The commitment was made by the HGA members to work for no profit,which allowed the family to make the additions and improvements.At weekly meetings,the team decided to pursue LEED Platinum status,to incorporate all renewable technologies that were economically feasible,but first and foremost we would incorporate high performance building science as our basic energy conservation methodology.Besides aiming for LEED Platinum status,the team also established the goal to rebuild this project as carbon neutral.A major decision had to be made with respect to the existing structure.To demolish the house or salvage the frame was a dilemma.Building from scratch would be easier,faster,and probably cheaper,but was it the most sustainable?Does saving the remains of a charred wood frame add or subtract from the overall carbon footprint?Certainly,bringing the framing and sheathing to the landfill is not a carbon friendly concept.The family was concerned that if we saved the structure,it would retain the smoky smell and wanted a guarantee that no odors would be perceived,even on the hottest summer days.We contacted a number of fire renovation companies and they all agreed that full encapsulation would have to be performed on the structure after we cleared the burned and structurally compromised framing away.The majority of the frame was structurally sound and it would be difficult to recycle it,so the decision was made to re-use the frame and most of the exterior sheathing including a good portion of the existing cedar shingles.

Mechanical properties and simulated thermal conductivity of biomimetic structured PS-PVD(Gd_(0.9)Yb_(0.1))_(2)Zr_(2)O_(7) thermal barrier coatings

Plasma spray physical vapor deposition(PS-PVD)(Gd_(0.9)Yb_(0.1))_(2)Zr_(2)O_(7)(GYbZ)thermal barrier coatings(TBCs)exhibited better silicate-phobicity than coatings produced by electron beam physical vapor depo-sition.In combination with PS-PVD and ultrafast laser direct writing technology,biomimetic structured GYbZ TBCs,with a triple-scale micro/nano surface microstructure,were obtained.Laser ablating on the PS-PVD GYbZ coating enhanced the surface roughness,improving its wear resistance without increasing the surface hardness.Furthermore,during the laser ablation processing,numerous nanoparticles were deposited in-situ in the gaps between columns of the coating,reducing the coating Young’s modulus.The simulated temperature field and heat flux field demonstrated that the presence of numerous interfaces between small columns of the PS-PVD coatings is beneficial to thermal insulation.However,laser ablation decreased the coating thickness,reducing the thermal insulation by around 20%-30%as compared to its PS-PVD counterpart,suggesting that a moderate increase in the coating thickness should be considered when designing an efficient TBC system.

聚氨酯硬泡外墙外保温技术在既有住宅楼节能改造中的应用

该技术在墙体外侧采用现场喷涂聚氨酯硬泡作为保温层,以钢丝网水泥砂浆作保护层,并用塑料胀管螺丝将基体和护层连为整体。具有轻质整体、高效保温、粘接牢固、防水、耐老化、施工方便等优点。15年工程实践检验证明,该技术工艺技术可靠,操作简便易行,监理检查直观,节能效果显著。既适用既有建筑维修改造,又适用于新建筑保温节能。该技术于2002年1月23日通过了吉林省建设厅组织的科技成果鉴定。