Water—ethanol—gasoline blends as spark ignition engine fuels

The miscibility characteristics of hydrated ethanol with gasoline is investigated as a means of reducing the cost of ethanol/gasoline blends for use as a spark ignition engine fuel. For a given percentage of water in the ethanol, the experimental data shows that a limited volume of gasoline can be added to form a stable mixture. Engine experiments indicate that, at normal ambient temperatures, a water/ethanol/gasoline mixture containing up to 6 vol% of water in the ethanol constitutes a desirable motor fuel with power characteristics similar to those of the base gasoline. As a means of reducing the smog causing components of the exhaust gases, such as the oxides of nitrogen and the unburnt hydrocarbons, the water/ethanol/gasoline mixture is superior to the base gasoline.     

能源、环境与空调制冷

１９９７年,世界上１６０多个国家在日本京都签订了有关减少温室气体排放的协议（京都协议）。该协议对缔约国的能源政策甚至经济的发展都有巨大的影响。作为能源消耗量很大的空调制冷行业,有必要对此予以充分的关注和深入研究。本研究了国内外能源环境现状和空调制冷系统与能源环境的关系,给出了对空调制系统适应新的能源结构和环境政策进行适当调整的建议。     

Fabrication of a New Polyimide/Titania (TiO2) Nanocomposite Thin Film by the Sol-Gel Route

Polyimide/titania nanocomposite (PI/TiO₂ NC) was successfully fabricated through the in situ formation of TiO₂ within a PI matrix by the sol-gel process. FT-IR and XRD results confirmed the formations of the TiO₂ in the PI matrix. Transmission electron microscopy of the NC10% showed that the TiO₂ phase was well dispersed in the polymer matrix. The mechanical properties of the NC films were increased and elongation at break decreased with increasing TiO₂ content. Thermogravimetric analysis results revealed that the decomposition temperature of hybrid materials was increased with an increase in the content of TiO₂ nanoparticles within the NC films.     

Effect of structural uncertainty on seismic response of steel moment-resisting frames equipped with tuned mass dampers

Tuned mass dampers (TMDs) can be used to absorb the input energy of the applied loads, and reduce the response of building frames. However, inherited uncertainties in structural characteristics of building frames can significantly affect their response and counteract the effectiveness of vibration absorbing devices such as TMDs. In this study, by calculating cumulative damage indices for stories of the structure, failure probability of two steel moment-resisting frames equipped with TMDs has been studied in presence of uncertainty in characteristics of the structure. Cumulative inelastic deformation of structural elements in each story has been used to calculate the damage representative of that story, based on weighted average approach. Even though the cumulative response of the deterministic model of the structures is reduced by installing TMDs, the results of the numerical simulations on the probabilistic response of the sample structures indicate that for the records that cause excessive damage in the lower stories of the structures, the effect of TMDs on failure probability of the structure can be detrimental.     

Nonlinear dynamic response of tall buildings considering structure–soil–structure effects

Numerous studies have shown that the interaction between adjacent buildings can result in changes in nonlinear dynamic response of structures, damage, and performance level, depending on the dynamic specifications of structures involved and the frequency content of the input motion. To study these effects, finite element method is used for the analytical investigations, and total soil–foundation–structure system is modeled all together. For modeling purposes and in order to realize the effects of the adjacent buildings on the dynamic response, two buildings, namely, 15‐story and 30‐story tall buildings, which were separated by distances of 1/4 and 1/8 of the width of the foundation and were located on hard and soft soil profiles, were considered. It was concluded that in the case where the soil and structure's periods were near to each other, the interaction of adjacent structures on increasing nonlinear responses (displacement and interstory drift) and structural damage indexes was noticeable and therefore was not negligible. Whereas in the case where periods are distant from each other, the interaction of adjacent buildings has a decreasing effect on damage indexes and nonlinear responses and therefore was negligible. Copyright © 2011 John Wiley & Sons, Ltd.     

An investigation on the behavior of stiffened coupled shear walls considering axial force effect

In most of tall buildings, the main contribution of lateral loads is carried by coupled shear walls. In some cases, the necessary stiffness to withstand the lateral load may not be afforded due to low depth of connecting beams. In order to increase the capacity of the coupled shear walls, beams with high stiffness are added to the system at particular levels. Hence, stiffened coupled shear walls (SCSW) will be produced. Such walls are under axial load resulting from their weight, and this axial load affects the behavior of walls because of their excessive height. In this paper, a new method considering the effect of axial force for geometrically nonlinear analysis of the SCSW has been presented. A computer program has been developed in matlab , and numerical examples have been solved to demonstrate the reliability of this method. The results of the examples show the agreement between the present method and the other methods given in the literature. The effects of the various positions and rigidities of the stiffening beam on the internal forces and the lateral deflection of the structure considering axial force effect have also been investigated. Copyright © 2012 John Wiley & Sons, Ltd.     

Extracting knowledge from building-related data — A data mining framework

Energy management systems provide an opportunity to collect vast amounts of building-related data. The data contain abundant knowledge about the interactions between a building’s energy consumption and the influencing factors. It is highly desirable that the hidden knowledge can be extracted from the data in order to help improve building energy performance. However, the data are rarely translated into useful knowledge due to their complexity and a lack of effective data analysis techniques. This paper first conducts a comprehensive review of the commonly used data analysis methods applied to building-related data. Both the strengths and weaknesses of each method are discussed. Then, the critical analysis of the previous solutions to three fundamental problems of building energy performance improvement that remain significant barriers is performed. Considering the limitations of those commonly used data analysis methods, data mining techniques are proposed as a primary tool to analyze building-related data. Moreover, a data analysis process and a data mining framework are proposed that enable building-related data to be analyzed more efficiently. The process refers to a series of sequential steps in analyzing data. The framework includes different data mining techniques and algorithms, from which a set of efficient data analysis methodologies can be developed. The applications of the process and framework to two sets of collected data demonstrate their applicability and abilities to extract useful knowledge. Particularly, four data analysis methodologies were developed to solve the three problems. For demonstration purposes, these methodologies were applied to the collected data. These methodologies are introduced in the published papers and are summarized in this paper. More extensive investigations will be performed in order to further evaluate the effectiveness of the framework.     

The impact of surface air movement on material emissions

The effects of surface air movement on material emissions were investigated experimentally. A field study was carried out to understand the characteristics of surface air movement in real rooms, and a velocity-controlled test chamber was designed and built, based on the field study results, to provide a uniform mean airflow and boundary layer condition over the test area. An extensive experimental study on the effects of air movement on material emissions was carried out, under different mean flow velocities and turbulence fluctuations, by using the small velocity-controlled test chamber. It was found that material emission rates are a function of the surface air flow conditions: as surface air velocity increases, contaminants from materials deplete faster, the turbulent fluctuation has a lesser effect on material emissions.     

Overland Water Flow and Solute Transport: Model Development and Field-Data Analysis

The application of plant nutrients with irrigation water is an efficient and cost-effective method for fertilizer application to enhance crop production and reduce or eliminate potential environmental problems related to conventional application methods. In this study, a combined overland water flow and solute transport model for analysis and management of surface fertigation/chemigation is presented. Water flow is predicted with the well-known Saint-Venant’s equations using a control volume of moving cells, while solute transport is modeled with the advection-dispersion equation. The 1D transport equation was solved using a Crank-Nicholson finite-difference scheme. Four, large-scale, field experiments were conducted on blocked-end and free draining furrows to calibrate and verify the proposed model. The results showed that application of solute during the entire irrigation event, or during the second half of the irrigation for blocked end conditions with appropriate inflow rates, produced higher solute uniformity than application of solute during the first half of the irrigation event. Measured fertilizer distribution uniformity of the low quarter ranged from 21 to 76% while fertilizer distribution uniformity of the low half values varied between 62 to 87%. The model was subsequently applied to the experimental data; results showed good agreement with all field data. Water balance errors for the different experiments varied from 0.004 to 1.8%, whereas fertilizer mass balance errors ranged from 1.2 to 3.6%. A sensitivity analysis was also performed to assess the effects of longitudinal dispersivity parameter on overland solute concentrations. A value of 10 cm for dispersivity provided a reasonable fit to the experimental data.     

Evaluation of Various Surface Irrigation Numerical Simulation Models

In this study, a zero-inertia model (ZIMOD) is presented to simulate all phases of border and furrow irrigation systems. The governing equations were discretized using a control volume of moving cells, by procedures reported in the literature for borders and for furrows. Later, the discretized equations were linearized by applying a Taylor series expansion according to the Newton-Raphson procedure, and then the algebraic linearized equations were iteratively solved using the Gaussian elimination technique. The ZIMOD was verified against several field experimental data and output of various numerical models in the SIRMOD package. Computational times, errors in predicting advance and recession trajectories, and estimated runoff and infiltrated volumes were compared. All models used in the comparative analysis predicted the advance and recession times and the infiltrated and runoff volumes satisfactory. However, models in the SIRMOD package were computationally faster than ZIMOD.