Envelope retrofit analysis using eQUEST,IESVE Revit Plug-in and Green Building Studio: a university dormitory case study

Three building analysis software programs, DOE-2 eQUEST, IESVE Revit Plug-in and Autodesk Green Building Studio, are used to quantify the predicted energy savings of a scheduled envelope retrofit on a university dormitory. The study includes investigating the potential energy savings created by the removal and replacement of all original windows and exterior non-structural infill brick panels coupled with installation of supplementary insulation materials between the new brick panels and the interior concrete masonry unit walls. The rehabilitation will take place in four over 7000 m² seven-storey residence halls originally constructed in 1965. Reports generated from baseline design simulations are compared with real energy consumption data in order to ascertain the accuracy of the three modelling programmes. Analysis of the retrofit proposal is carried out by comparing results of each retrofit design alternative against the baseline and assessing CO ₂ emissions reduction resulting from the proposed retrofit process. Advantages and disadvantages of each modelling programme are also discussed.     

Analysis technique for interaction of high-frequency rhombicinducer field with cracks in metals

In the nondestructive evaluation (NDE) involving the ac field measurement (ACFM), a current carrying structure is required to induce the eddy current in the work-piece and a probe to sample the field. Due to its flat profile, slender shape, and other advantages, the rhombic wire loop is a suitable inducer for developing linear flexible arrays for the ACFM inspection of large surfaces of ferrous and nonferrous metals. This paper introduces an analysis technique for the evaluation of the interaction of the field of the rhombic inducer carrying a high-frequency current, with long surface cracks of uniform depth in flat metal plates. The technique is accurate and very efficient computationally. It uses the two-dimensional Fourier transform together with a special boundary condition at the metal surface. The boundary condition takes into account the thin-skin nature of the eddy current in the metal as well as the flux leakage at the crack mouth. The analysis technique benefits from the use of scalar potential functions and can be extended to simply or multiply connected wire loops. Also, it is applicable to high-frequency (thin-skin) eddy current problems. Using the analysis technique, the tangential field below a rhombic inducer along its long diagonal when the inducer is located above the surface of aluminum and steel is given in the presence and absence of a crack. This field was found to have a nonuniform phase distribution. Near a crack, the phase change is significant, even for shallow cracks. The role of the nonuniform phase in the detection sensitivity is addressed. Also, simulated ACFM crack responses using an inducer with a linear probe attached along the long diagonal are presented and discussed. To support the validity of the analysis technique, experimental results obtained for some of the simulations are also reported. In addition to its application in predicting crack responses, the technique can be used for model-based inversion of crack signals     

Fracture of aluminium alloy 2024 under biaxial and triaxial loading

Previous studies on multi-axial fracture of metals have shown that the critical J-integral at fracture may be less than the fracture toughness measured in a standard test. This gives rise to the question: what is the minimum critical J-integral and how can it be obtained? To answer this question a series of uniaxial, biaxial and triaxial tests were carried out. Conducting biaxial and triaxial tests allows the effects of stress state in the fracture of metallic materials to be investigated, particularly when the plasticity is highly constrained. The primary purpose of this paper is to report the experimental findings of the tests performed on specimens fabricated from aluminium alloy 2024. Results of finite element analyses are then used to study further the detailed stress state near the crack tip and to evaluate the intensity of the plastic deformation and relate it to the critical J-integral variation. It was found that indeed high triaxial loading, corresponding to limited plastic deformation prior to the fracture, decreases the critical J-integral even below the values obtained from the biaxial tests, which are already less than the standard uniaxial value.     

Selecting Appropriate Project Delivery System: Fuzzy Approach with Risk Analysis

The selection of an appropriate project delivery system that suits all project and owner needs is one of the key decisions to a successful project. Therefore, this decision should be made based on thorough analysis. In this paper, a fuzzy multiattribute decision-making (FMADM) model is developed. The model accounts for uncertainties and imprecision in the decision space as well as fuzziness in the nature of the decision attributes. The model utilizes fuzzy decision-making approach in order to evaluate the membership function corresponding to the utility of each project delivery alternative. Project delivery system alternatives are ranked using fuzzy technique for order preference by similarity to ideal solution (TOPSIS) method based on their utility membership functions and by evaluating the distance of each project delivery alternative from fuzzy ideal solutions. In the TOPSIS method, alternatives are ranked based on their closeness coefficient (CC). In addition, the risk attitude of the decision maker is considered in the model by using derived utility membership functions corresponding to the risk attitude of the decision maker. The model is applied to a petrochemical project as a case study. In the case study, the model outcome that ranked Turnkey system as the best system conforms to the lessons learned by the decision maker from several past projects. Moreover, sensitivity analysis is done in the case study. The results show the significant value of the FMADM model for selecting appropriate project delivery system for projects.     

Correction de rotation continue en mesures de champs proches

In near-field techniques applicable to large antennas the measurements are often made through the scanning of a meridian of the desired surface for different orientations of the test antenna. Utilisation of a probe array permits a rapid analysis of the field along that meridian. As shown in this paper, it is not necessary to stop the movement of the antenna during measurements along the meridian, if a simple scheme for continuous rotation of the test antenna is utilised.     

Potassium‐catalyzed steam gasification of ash‐free lignite coal with CO2 capture

The purpose of this research was to study steam gasification of ash‐free coal integrated with CO₂ capture in the presence of a K₂O catalyst for enhancement of the key water‐gas shift reaction and promotion of hydrogen production. To achieve this goal, gasification experiments on ash‐free coal (AFC) were carried out at varying temperatures (600, 650, 675, 700, and 750 °C) with a sorbent‐to‐carbon (CaO/C) ratio of 2 and a catalyst (K₂O) loading of 0.2 g/g (20 weight percent (wt%)) in a fixed‐bed reactor equipped with a gas chromatography analyzer. The sorbent‐to‐carbon (CaO/C) ratio of 2 is based on dry and ash‐free basis. The CaO/C ratio and K₂O wt% were chosen to maximize hydrogen production based on our previously determined optimal values. The AFC was originally extracted from raw lignite coal using organic solvents, which allowed the sorption‐enhanced gasification to be conducted with minimal ash‐catalyst interactions. The effect of temperature on the yield and the initial reaction rate were investigated. The optimal reaction temperature of 675 °C was determined. Carbon balance and final carbon conversions were calculated based on the residue analysis. Activation energy was also calculated using intrinsic kinetics of the reaction. In this study, using AFC offered the potential advantage of operating the gasification process with catalyst recycle.     

Electropolymerization of thionine as a stable film along with carbon nanotube for sensitive detection of tetracycline antibiotic drug

Iranian Polymer Journal - Herein, a simple, rapid, cost-effective and sensitive poly(thionine)-based electrochemical sensor is described to determine trace amounts of tetracycline. In the present...     

Physical characterization and rheological behavior of polyurethane/poly(ϵ-caprolactone) blends,prepared by solution blending using dimethylacetamide

Blending effects of thermoplastic polyurethane based on polycaprolactone diol, PU (PCL diol), and poly (ϵ-caprolactone) (PCL) on the rheological properties and morphological behavior of the solvent-cast blends were investigated by parallel plate rheometer. The amount of PCL was varied from 20 to 50% by weight. Fourier transform infrared (FTIR) results showed existence of hydrogen bonding in PU/PCL blends. From FTIR, we also found the increase of PCL composition tends to reduction of intermolecular hydrogen bonding and enhancing of microphase separation in blends. Differential scanning calorimetry (DSC) indicated that these blend systems are partially miscible. Based on rheological characterization, decrease can be seen in the moduli, zero shear viscosity and plateau modulus of blends, as compared with net PU. Using Cole-Cole plots and composition dependencies of η₀ and the other viscoelastic functions expressed variation of morphology of blends due to increase of PCL content. Frequency sweep tests on PU/PCL (80/20) at five temperatures showed validity of time-temperature superposition in this blend. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Ionic liquid ultrasound assisted dispersive liquid-liquid microextraction method for preconcentration of trace amounts of rhodium prior to flame atomic absorption spectrometry determination

In this article, we consider ionic liquid based ultrasound-assisted dispersive liquid-liquid microextraction of trace amounts of rhodium from aqueous samples and show that this is a fast and reliable sample pre-treatment for the determination of rhodium ions by flame atomic absorption spectrometry. The Rh(III) was transferred into its complex with 2-(5-bromo-2-pyridylazo)-5-diethylamino phenol as a chelating agent, and an ultrasonic bath with the ionic liquid, 1-octyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide at room temperature was used to extract the analyte. The centrifuged rhodium complex was then enriched in the form of ionic liquid droplets and prior to its analysis by flame atomic absorption spectrometry, 300 μL ethanol was added to the ionic liquid-rich phase. Finally, the influence of various parameters on the recovery of Rh(III) was optimized. Under optimum conditions, the calibration graph was linear in the range of 4.0-500.0 ng mL(-1), the detection limit was 0.37 ng mL(-1) (3S(b)/m, n = 7) and the relative standard deviation was ±1.63% (n = 7, C = 200 ng mL(-1)). The results show that ionic liquid based ultrasound assisted dispersive liquid-liquid microextraction, combined with flame atomic absorption spectrometry, is a rapid, simple, sensitive and efficient analytical method for the separation and determination of trace amounts of Rh(III) ions with minimum organic solvent consumption.