Electron beam processed surface textures on titanium alloys for fluid-drag reduction

Ti-6Al-4V and Ti-4Al-1.5Mn alloys were employed for electron beam processing with the aim to produce surface textures efficient for fluid-drag reduction. The as-resulted surface textures were examined by using advanced optical microscopy for surface morphology analysis, optical microscopy and scanning electron microscopy for near-surface microstructure observation. The titanium model with electron beam processed surface textures was tested in wind tunnel to evaluate their fluid-drag reduction efficiency. It showed that the as-resulted non-smooth surface was characterized by parallel ridges and grooves, with height and spacing able to be customized by adjusting processing parametres. The ridges displayed continuous scales while the valley of grooves presented V-shaped ripples. Their dimensions were also related to and could be controlled by processing parametres. Further, the near-surface region was occupied by fusion zone, heat-affected zone and base metal from the outermost surface to the underlying bulk alloy. The microstructure of fusion zone was characterized by martensite phase. A heat-affected zone was sandwiched between fusion zone and the underlying base metal, with different microstructural features compared to both fusion zone and the base metal. With respect to fluid-drag reduction efficiency, titanium model with electron beam processed surface textures exhibits a reducing efficiency over 15% at attack angles of 0° and ±1°, with an air flow velocity at 24 m/s.     

The role of psychology and social influences in energy efficiency adoption

Current energy efficiency policy and incentive programs tend to target economic motivations, which may misalign with other potentially important motivations arising from situational factors, individual differences, and social context. Thus, in this research, we review areas of work that have focused on psychological and social influences to energy efficiency adoption in commercial buildings. We then conduct an empirical scoping study interviewing 10 commercial building owners/managers (decision makers) and 10 experts/consultants (decision influencers) regarding perceived motives and barriers to energy efficient investments, decision-maker attributes, and the social context of the decision. Potential factors that emerge from the interviews, which are not yet extensively discussed in the energy efficiency literature, include owners/managers’ resistance to change and the influence of investment funding origins on the decision. Our results also suggest potential heterogeneity in energy efficiency decision-making philosophies between the two groups. Interviewed owners/managers prioritize corporate social responsibility (CSR) and prefer internal consulting (e.g., building engineers). Conversely, experts/consultants do not emphasize CSR and are more concerned with external policies. These findings suggest that accounting for the decision maker and the social context in which decisions are made could enhance the design of commercial sector energy efficiency programs.     

Climate dependence of energy saving strategies in public buildings characterized by change of use: an original case study

In the perspective of reducing land occupation of built environments, the most efficient strategy is to increase the reuse of obsolete or abandoned constructions instead of designing new buildings. This is particularly true regarding public buildings, usually characterized by considerable dimensions. The paper is focused on this issue, particularly on its energy implications. It analyzes the headquarters of the “G. D’Annunzio” University in Pescara, Italy, initially designed for commercial use and later converted to a university building during its construction. The authors first carried out a numerical analysis of the building energy performance in its current state and then they proposed some improvement interventions evaluating their incidence on the annual energy balance of the building, showing how the most commonly used energy saving strategies do not give the best results in any case, being greatly influenced by the climatic zone in which the building is located. Starting from these considerations, the authors carried out the analysis by considering three different Italian climatic conditions so as to determine their influence on the building energy performance and to define the best strategy for energy requalification in each climatic zone.     

Evaluation on Dorsey Method in Surface Tension Measurement of Solder Liquids Containing Surfactants

With the purpose of developing a feasible approach for measuring the surface tension of solders containing surfactants, the surface tension of Sn–3Ag–0.5Cu–xP solder alloys, with various drop sizes as well as different phosphorus (P) content, was evaluated using the Dorsey method based on the sessile drop test. The results show that the accuracy of the surface tension calculations depends on both of sessile drop size and the liquid metal composition. With a proper drop size, in the range of 4.5 mm to 5.3 mm in equivalent spherical diameters, the deviation of the surface tension calculation can be limited to 1.43 mN·m^?1 and 6.30 mN·m^?1 for SnAgCu and SnAgCu–P, respectively. The surface tension of SnAgCu–xP solder alloys decreases quickly to a minimum value when the P content reaches 0.5 wt% and subsequently increases slowly with the P content further increasing. The formation of a P-enriched surface layer and Sn₄P₃ intermetallic phases is regarded to be responsible for the decreasing and subsequent increasing of surface tension, respectively.     

Controlled Creating of Cracks in Concrete for Non-destructive Testing

The non-destructive assessment of cracks in concrete is a common task for which non-destructive evaluation solutions have been published. Primarily, these tests have been carried out on artificial cracks that have been created by using notches instead of natural cracks. This study evaluates a procedure designed to create reproducible and controlled cracks in concrete. The procedure is based on using expanding mortar in a series of blind holes. This is done in combination with carefully aligned reinforcement to guide the direction of the crack development. The depth of the crack is also controlled by reinforcement. Crack depth varies statistically in the range of the maximum aggregate size (16 mm) used for concrete.     

A model of energy management analysis,case study of a sugar factory in Turkey

This study presents a case study of energy management in a sugar factory in Turkey. The main idea of the study is to analyse energy consumption, the quantity of material production, and figure out a suitable energy efficiency for the case study of a sugar factory subsequently. Firstly, a material production and energy consumption audit were performed for the sugar factory. Secondly, energy efficiency was calculated from the energy data. The SPSS (Statistical Package for the Social Sciences) statistical software was used to ensure the accuracy of the data. The factory’s energy consumption was calculated as 43,590.25 toe (tons of oil equivalent) over the last year. These results were used for CUSUM (Cumulative Sum Deviation Method) graphics. This research poses the consumption of energy, cost of energy and the relationship between energy usage and material production of sugar. The unit of energy cost was 688.22 [$/toe] for the last year. This result showed that the factory decreased the unit of energy by optimisation. The results indicated that the investigated sugar factory should pay attention to the energy management issue in order to comply with the Energy Efficiency of Turkish Law and Directives.     

Thermal,electrical, mechanical and fluidity properties of polyester-reinforced concrete composites

Polyester particles in concrete are preferred because they provide thermal, chemical and water resistance. In this study, thermal conductivity, electrical resistivity, mechanical strength and water resistance properties of concretes containing polyester granules such as flame-retardant polyester, cationic dyeable polyester and polyester with a low melting point-filled concrete have been analyzed using a full factorial design via Minitab^® version 17. The effect of the most influential factors on thermal conductivity of polyester aggregate reinforced concrete composite has been determined as an interaction between the cationic dyeable and low-melt–point polyester. This mixture is suitable for production of thermal insulating concrete. Moreover, it is concluded that cationic dyeable polyester is the highest corrosion- and water-resistant product among the polyesters used in this study. The recovery rate of 33.94% in the thermal conductivity and 214.89% in the electrical resistivity of polyester-reinforced concrete composites has been obtained with a 28-day compressive strength loss of 41.94% according to the reference concrete in the full factorial design application. These results indicate that the polyester-reinforced concrete composites are quite effective in achieving thermal and corrosion resistance concrete but with noticeable compressive strength loss.     

A New Method for Siting Hazardous Units in Chemical Process Facilities Which Minimizes Risk at Least Cost: RIDIMPUS

A new method, RIsk and DIstance Minimization in Process Units Siting (RIDIMPUS), is presented with which hazardous units can be sited in a chemical process facility in a manner that the risk of accidents involving the hazardous units as also the cost of spacing the units is minimized. To achieve this, safety and cost factors were modeled using various governing parameters and then expressions were designed to integrate the safety and the economic concerns to form model equations, inequalities and disjunctions. The resulting nonlinear programming model is solvable by using algorithms and solvers on any common desktop computer, thereby providing an optimal and prompt solution.     

温拌LDPE改性沥青混合料性能研究

选择Sasobit和Evotherm 3G两种温拌剂对温拌LDPE沥青混合料制备工艺和性能进行研究。首先,比较变温等体积法和等黏温度法两种方法,并确定两种温拌混合料的拌和及击实温度。在此基础上,分别采用车辙试验、低温弯曲试验、中点加载弯曲试验以及冻融劈裂试验评价70#、LDPE、Sasobit-LDPE以及3G-LDPE四种沥青混合料的高温性能、低温性能、疲劳性能和水稳定性。结果表明,两种温拌技术均是可行的,Sasobit和3G温拌技术可使施工温度降低20℃和15℃。与热拌LDPE沥青混合料相比,Sasobit温拌沥青混合料具有更好的高温性能和水稳定性,在高应力比条件下抗疲劳性能更好,低温性能虽变差,但是优于70#沥青混合料;3G温拌沥青混合料的高温性能,低温性能以及水稳定性则与热拌LDPE沥青混合料各项性能较为接近,抗疲劳性能变差,但是优于70#沥青混合料。     

Experimental and Modeling Studies on the Chemical Vapor Infiltration with Respect to the Effects of Thermal Gradient and Other Operating Parameters

Effects of operating parameters in the thermal gradient chemical vapor infiltration of propane such as thermal gradient, diffusion, infiltrations time, and concentration of propane were studied by focusing on the visualizations of the intrinsic effects of these parameters. A uniform deposition in the preform was obtained with a gradually increasing temperature along the gas flow. The uniformity of deposition through the preform got improved with increasing deposition time. Results of numerical modeling estimated the experimental data very well when the pre-exponential factor of the overall rate of carbon deposition from propane reported by Vaidyaraman[1] was multiplied by 4. The average density of a preform increased by about 3 times from 0.38 to 1.15 g/cm3 after 60 hr deposition with a thermal gradient under the conditions of 3% propane in nitrogen and 840 to 900 ℃.