The effects of extremes and temporal scale on multifractal properties of river flow time series

For accurate forecasting of extreme events in rivers, streamflow time series with sub‐daily temporal resolution (1–6 hour) are preferable, but discharge time series for long rivers are usually available at daily or monthly resolution. In this study, the scaling properties of hourly and daily streamflow time series were measured. As an innovation, the effects of extreme values on the multifractal behavior of these series were evaluated. Interestingly, both hourly and daily discharge records led to nearly identical scaling trends and identical crossover times. Daily and hourly discharge time series appeared to be non‐stationary when the timescale ranged from 75 to 366 days. Otherwise, the signals may be considered stationary time series. In addition, the results indicated that the extreme values strongly contribute to the multifractality of the series. The width of singularity spectra decreased considerably when the extreme events were removed from both hourly and daily discharge records.     

Role of bazaars as a unifying factor in traditional cities of Iran: The Isfahan bazaar

A city is a vital organism that lives and grows like other organisms. Therefore, implementing development plans that would provide a sense of unity and integration in relation to the city as a whole is necessary. Traditional Iranian architecture is full of samples evolved during the course of Iranian history that can serve as architectural paragons of the city. In Iran's traditional cities, a sense of unity exists in various urban areas. The traditional city of Isfahan is one of the most valuable samples and was selected as the case study in this research. Accordingly, the most important questions of this research are as follows: (1) What is the role of bazaars in creating a sense of unity in the traditional cities of Iran? (2) How do bazaars play out their role in the integration of these cities? This research focuses on the concept of a “traditional city” to determine the role of bazaars in such cities. The results show that bazaars are crucial in giving a sense of integrity to the concept of a traditional Iranian city. Bazaars provide cohesion among the different parts of cities, such as residential areas, as well as socio-political and trade centers. This condition means that traditional bazaars play two important roles in traditional cities: (1) they interconnect the different parts of the city's physical structure; and (2) the crucial role of bazaars in a city's social and cultural structure brings about unity among the citizens in the city. Bazaars as a unifying element connect the main urban functions and guarantee the city's economic and social life.     

Flow properties of tool steel powders for selective laser melting – influence of thermal and mechanical powder treatments

In powder bed fusion additive processes the flow properties of the powder influence the quality of the final component and the efficiency of the process. In this investigation an attempt is made to identify flowability indicators which can describe the flow performance of the powder during the powder layering (i.e. recoating) step; common to all powder bed fusion processes. To this end, shear tests were performed by means of a powder rheometer. Bulk density, flow function and degree of cohesion were measured. The results suggest that there is a good correlation between the aforementioned parameters and the flowability of the powder during SLM processing. In addition, it was found that thermal treatments and tumbling enhance flowability. Thermal treatments were performed at 150, 200 and 250°C for a period of 10?min and in air.     

Experimental investigation of preparing and using the H2O based nanofluids in the heating process of HVAC system model

In this experimental work, three types of water-based nanofluids are prepared by ultrasonic method. SiO₂, TiO₂ and CNT nanoparticles are used for preparing the nanofluids. Applications of these nanofluids are examined in the heating process in HVAC systems. During the experiments, total dissolved solids (TDS) of nanofluid are measured to see which nanofluid is more appropriate in heating process and makes the lower deposits and sediments. Also, heated area and nanofluid temperatures are recorded to show which nanofluid in suitable for heating from energy consumption view point. Results show that SiO₂ can be more suitable from the energy consumption view point because by lower energy consumptions, it reaches to desirable temperature in the heated area.     

Emotional evaluation of architectural interior forms based on personality differences using virtual reality

Recent studies have shown that architectural interior forms could impact the affective state of inhabitants. However, the direct relation of specific forms with specific affective states is difficult to determine. In addition, no systematic categorization of architectural forms and their relation to emotional states exists. The investigation of the impact of architectural features on inhabitants' emotions is further complicated by the use of two-dimensional images of forms in laboratory investigations, which cannot perceive real-world architecture. Furthermore, the interior form consists of a combination of different forms rather than only pure forms, which was considered in previous studies. This study aimed to fill these gaps by evaluating interior forms on the basis of clustering different images of built living rooms throughout history as well as their impact on emotions. This study used pleasure, arousal, and dominance ratings with an emphasis on individual differences in personality. Virtual sample rooms were created based on formal clusters of architectural forms. Results showed a relationship between forms and emotional states for different personality traits. This work provided a novel approach on the influence of architecture on emotion by considering systematic form categorization and combinations, personality differences, and a virtual reality setup.     

循环荷载下组合剪力墙的性能评估

组合钢板剪力墙(CSSW)由于其具有极高的刚度及可变性,在土木工程领域内应用广泛。它可以用于混凝土覆层,与钢板采用剪切螺钉连接,或者与FRP板黏结。现有的试验和数值研究集中在剪切螺钉间距变化时,梁跨中刚度和梁柱连接方法对组合钢板剪力墙的影响上。结果显示:剪切螺钉间距的增加使荷载-位移曲线斜率减小,改善了由特定螺钉间距影响的延性。此外,梁跨中刚度和梁柱节点对组合钢板剪力墙也有很显著的影响。     

Numerical study of film cooling effectiveness of a gas turbine blade under variable blowing ratio and turbulence intensity

The present paper investigates a three-dimensional simulation of film cooling on a C3X turbine blade with a single hole at a suction surface. The Reynolds averaged Navier–Stokes approach with k–ε realizable turbulence model and enhanced wall function are used for the numerical simulation. To simulate the jet flows, the length of the jet input approximately 4.5 times the diameter of the hole is added to the geometry so that the jet outlet flow is closer to the actual condition. The density ratio of the cooling flow to the mainstream flow is assumed about 2. The numerical results in four blowing ratios of 0.5, 0.7, 1.0, and 1.4, and at the low turbulence intensity (0.02%), and high turbulence intensity (12%) are extracted and compared for the turbine blade with a single hole. The results show that the turbulence intensity has a dual effect on the film cooling effectiveness and a higher blowing ratio increases the strength of the jet against the cross-flow. Moreover, it is illustrated that the distribution of the film cooling effectiveness in higher blowing ratios and high turbulence intensity is more uniform than the low blowing ratios and low turbulence intensity.     

Viscosity of pure carbon dioxide at supercritical region: Measurement and correlation approach

In this paper a method to calculate the viscosity of supercritical CO2 is introduced. A rolling body viscometer equipped with a gas booster was used. Based on new experimental and available data, a new correlation is developed. The proposed correlation is valid in temperature range from 310 K to 900 K. Moreover, the model predictions are acceptable in pressures between 7.5 and 101.4 MPa. The model superiority over other conventional methods has been demonstrated.