Community perception of the Klimkówka Reservoir in Poland

This article presents the results of a survey on how people perceive the Klimkówka storage reservoir located on the Ropa River in the Polish Carpathians. The analysis focused on establishing the role of various factors which impact the assessment of the reservoir by the local community. Community perception of the reservoir was analyzed in relation to several aspects linked to the reservoir itself, e.g. the risk of dam failure, feeling of safety, pros and cons, and how accustomed people were to the reservoir. A crucial issue was to identify how the real threat of a flood, experienced by people living below the dam, affected the way people perceived the reservoir. As a result of the analysis, a hierarchy of factors which determine people's assessment of large hydraulic structures was established. The results can be applied to determine specific measures aimed at limiting negative community perception of water infrastructure.     

Cost-Benefit Analysis of Dam Projects: The Perspectives of Resettled and Non-resettled Communities

The research focuses on the perception of the Mucharz reservoir in relation to costs and benefits for two types of communities. The primary aim of the paper is to compare the social impact of dam projects among both resettled and non-resettled local communities. The secondary aim of the paper is to test multivariate analysis of variance (MANOVA) as a tool to examine the social impact assessment (SIA) of dam projects. The studied dam is located on the Skawa River within the Polish Carpathians. We used in-depth interviews with a non-resettled (N?=?96) and resettled (N?=?57) local population. To analyse the collected data, we performed multivariate analysis of variance. The main results indicate that the social assessment of dam projects differs significantly depending on whether one belongs to the group of resettled or non-resettled population. MANOVA is an effective tool for the analysis of the social impact assessment (SIA) of dam projects.

     

抽水蓄能机组主轴密封故障分析及新型密封环研制

分析了天荒坪抽水蓄能机组运行时主轴密封的失效原因。运用流体静力学理论,分析了密封摩擦面的承载机理,提出了保持操作腔的压力随尾水压力变化而变化是保证水膜承载能力与负载平衡的关键,并导出了计算公式,为系统结构改造提供了理论依据。原密封环属于木纤维素浸渍酚醛树脂制品,其使用最高温度为(150～200)℃。新型密封环采用减摩改性高温树脂,混合有机芳纶(KEVLAR)碳纤维与无机纤维,并添加了石墨粉、二硫化钼粉、铜粉等固体润滑剂,其使用最高温度为(250～300)℃。最后介绍了新型密封环的生产工艺流程。     

Laminar free convection from a continuously-moving vertical surface in thermally-stratified non-Darcian high-porosity medium: Network numerical study

A mathematical model is presented for the two-dimensional, steady, incompressible, laminar free convection flow boundary layer flow over a continuously moving plate immersed in a thermally-stratified high-porosity non-Darcian porous medium, in an (x,y) coordinate system where x is directed along the plate. Stratification is assumed to be stable and is analyzed using an algebraic formulation relating the stratification rate of the gradient of ambient temperature with the vertical distance along the plate (x). A Darcy–Forchheimer drag force model is used to simulate the bulk porous resistance at low Reynolds numbers, and the inertial quadratic drag at higher Reynolds numbers. The governing conservation equations are non-dimensionalized with appropriate transformations into a (ξ,η) coordinate system and they are solved using the Network Simulation Method (NSM) using the Pspice algorithm database.     

Stripping of copper coatings from steel in Cr(VI)-free commercial bath

In this work the electrochemical characteristics of copper and steel in chromate, cyanide, and phosphate baths as well as in a commercial bath (ENSTRIP S-180), in the absence of chromium and cyanides were determined. Average rates of copper coatings stripping from steel in the above mentioned baths and the baths influence on the morphology of steel surfaces were described. It was found that the commercial bath ENSTRIP S-180 could be successfully used for stripping of copper coatings from steel elements.     

Micromechanical modeling of grain boundary resistance to cleavage crack propagation in ferritic steels

In ferritic steels a propagating cleavage microcrack changes its propagation direction as it advances from grain to grain. This is due to differences in the orientation of the cleavage planes of two neighboring grains. In order to reach a cleavage plane in a new grain, a microcrack must first penetrate the grain boundary. Grain boundaries therefore act as natural barriers in cleavage fracture. The influence of a grain boundary and the associated misorientation in cleavage planes on crack arrest is here examined using a 3D finite element model with axisymmetric periodicity, representing two grains whose cleavage planes are tilted and twisted relative to each other. The temperature dependent mechanical properties of ferrite are modeled using a temperature dependent viscoplastic response. The development of the crack front as the microcrack penetrates through a grain boundary is here presented. The influence of the twist misorientation on the critical grain size, defined as the largest grain size that can arrest a rapidly propagating microcrack, is examined in a temperature range corresponding to the ductile to brittle transition (DBT) region. It is shown that when both tilt and twist misorientation are present, the influence of tilt and twist, respectively, on crack growth resistance can be decoupled.     

The effect of changing excitation frequency on parallel conductance in different sized hearts

OBJECTIVE: An important component of the ventricular volume measured using the conductance catheter technique is due to parallel conductance (Vc), which results from the extension of the electric field beyond the ventricular blood pool. Parallel conductance volume is normally estimated using the saline dilution method (Vc(saline dilution)), in which the conductivity of blood in the ventricle is transiently increased by injection of hypertonic saline. A simpler alternative has been reported by Gawne et al. [12]. Vc(dual frequency) is estimated from the difference in total conductance measured at two exciting frequencies and the method is based on the assumption that parallel conductance is mainly capacitive and hence is negligible at low frequency. The objective of this study was to determine whether the dual frequency technique could be used to substitute the saline dilution method to estimate Vc in different sized hearts. METHODS: The accuracy and linearity of a custom-built conductance catheter (CC) system was initially assessed in vitro. Subsequently, a CC and micromanometer were inserted into the left ventricle of seven 5 kg pigs (group 1) and six 50 kg pigs (group 2). Cardiac output was determined using thermodilution (group 1) and an ultrasonic flow probe (group 2) from which the slope coefficient (alpha) was determined. Steady state measurements and Vc estimated using saline dilution were performed at frequencies in the range of 5-40 kHz. All measurements were made at end-expiration. Finally, Vc was estimated from the change in end-systolic conductance between 5 kHz and 40 kHz using the dual frequency technique of Gawne et al. [12]. RESULTS: There was no change in measured volume of a simple insulated cylindrical model when the stimulating frequency was varied from 5-40 kHz. Vc(saline dilution) varied significantly with frequency in group 1 (8.63 +/- 2.74 ml at 5 kHz; 11.51 +/- 2.65 ml at 40 kHz) (p = 0.01). Similar results were obtained in group 2 (69.43 +/- 27.76 ml at 5 kHz; 101.24 +/- 15.21 ml at 40 kHz) (p < 0.001). However, the data indicate that the resistive component of the parallel conductance is substantial (Vc at 0 Hz estimated as 8.01 ml in group 1 and 62.3 ml in group 2). There was an increase in alpha with frequency in both groups but this did not reach significance. The correspondence between Vc(dual frequency) and Vc(saline dilution) methods was poor (group 1 R2 = 0.69; group 2 R2 = 0.22). CONCLUSION: At a lower excitation frequency of 5 kHz a smaller percentage of the electric current extends beyond the blood pool so parallel conductance is reduced. While parallel conductance is frequency dependent, it has a substantial resistive component. The dual frequency method is based on the assumption that parallel conductance is negligible at low frequencies and this is clearly not the case. The results of this study confirm that the dual frequency technique cannot be used to substitute the saline dilution technique.     

The application of NASICON (Na2Zr2Si2PO12) to the thermodynamic study of beta-alumina

The solid-state galvanic cell with NASICON as an auxiliary electrolyte was built. The standard free enthalpy, entropy and enthalpy of beta-alumina formation as well as the Na₂O-activity in the alpha-alumina—beta-alumina coexistence region were determined in the temperature range 970–1220 K. The limiting temperature of spontaneous decomposition of beta-alumina was also estimated. The results were compared with those obtained by other authors.     

Occupational posture exposure among construction electricians

The aim of this study is to record, objectively describe and compare working postures of Brazilian and Norwegian construction electricians. Postures of the upper arms, head, and neck during work and breaks were quantified by means of inclinometry for a representative sample of 12 Brazilian and 12 Norwegian electricians in the construction industry during a full work-shift. Despite that differences were found between specific work-related factors, Brazilian and Norwegian workers revealed a high and very similar level and pattern of postures for all evaluated body regions, suggesting that results could be extrapolated to other electricians. Upper arm elevation was high and similar for both groups and head flexion and extension was pronounced compared to other occupations. Thus, extreme postures were identified for construction electricians in both countries, with similar exposure pattern also for defined tasks (planning, support and wiredraw), suggesting that this job is risky regardless organizational differences.