Ductile moment-resisting frames using cold-formed steel sections: An analytical investigation

This paper presents an investigation on the potential use of cold-formed steel sections (CFS sections) in moment-resisting frames (MRFs) for seismic applications. The main limitation of CFS sections is the low out-of-plane stiffness of their thin-walled elements which leads to low ductility. The main components of MRFs are beams, beam-column connections and columns. In earthquake resistant MRFs, the beams are designed to provide considerable ductility, whereas the other elements are mainly limited to their elastic range. The performance of a new shape of CFS beam with curved flange is examined analytically and compared with that of conventional shapes. The proposed beam-column connections include through plates which potentially limit the out-of-plane action of the forces transferred through the connections. The behaviour of both individual CFS beam sections and CFS beam-column connections is studied by means of finite element analysis (FEA). The results of the analyses show that the new beam cross sections and connections exhibit a good ductile behaviour, something which cannot be achieved by conventional cold-formed frame elements.     

Decontamination of Bacillus cereus in cardamom (Elettaria cardamomum) seeds by infrared radiation and modeling of microbial inactivation through experimental models

In this work, infrared (IR) irradiation was used for inactivation of Bacillus cereus in cardamom seeds. The effect of IR power (100, 200, and 300 W), sample distance from radiation source (5, 10, and 15 cm) and holding times (0–11 min) was investigated on B. cereus count, as well as cardamom seeds color and temperature profiles. Inactivation of B. cereus on cardamom seeds during IR processing was demonstrated by experimental models. The highest reduction of B. cereus count (5.11 Log CFU/g) was achieved after 8 min IR irradiation at 300 W power and 15 cm distance. Measurement of temperature profiles revealed that there was a significant difference (p < .05) between surface and center temperatures of the cardamom seeds. The green color (a* value) of cardamom seeds was slightly affected and the highest color change was observed at 200 W IR, 10 cm distance and 10 min irradiation that resulted in an increase of a* from −3.05 ± 0.96 to −0.05 ± 0.44. In conclusion, IR irradiation could be successful for decontamination of cardamom seeds without severe alteration of its quality. Among the experimental models for microbial inactivation during IR processing, the Double Weibull model had the highest coefficient value of determination (R² = 0.9966).     

Evaluation of Data Mining Strategies for Classification of Black Tea Based on Image-Based Features

In this study, a new procedure based on computer vision was developed for qualitative classification of black tea. Images of 240 samples from four different classes of black tea, including Orange Pekoe (OP), Flowery Orange Pekoe (FOP), Flowery Broken Orange Pekoe (FBOP), and Pekoe Dust One (PD-ONE), were acquired and processed using a computer vision system. Eighteen color features, 13 gray-image texture features, and 52 wavelet texture features were extracted and assessed. Two common heuristic feature selection methods: correlation-based feature selection (CFS) and principal component analysis (PCA), were used for selecting the most significant features. Seven of the primary features were selected by CFS as the most relevant ones, while PCA converted the original variables into 11 independent components. These final discriminatory vectors were evaluated by using four different classification methods including decision tree (DT), support vector machine (SVM), Bayesian network (BN), and artificial neural networks (ANN) to predict the qualitative category of tea samples. Among the studied classifiers, the ANN with 7–10–4 topology developed by CFS-selected features provided the best classifier with a classification rate of 96.25%. The other methods assayed provided slightly lower accuracies than ANN from 86.25% for BN till 87.50% for SVM and 88.75% for DT. In all the cases, the accuracy of the classifiers increased when using the CFS-selected features as input variables in front of PCA obtained ones. It can be concluded that image-based features are strong characterizing factors which can be effectively applied for tea quality evaluation.     

Prediction of proton conductivity of graphene oxide-containing polymeric membranes

In the present work we examined the capability of a simple Nernst–Planck based model to predict the proton conductivity of polymeric membranes which contained pristine or functionalized graphene oxide sheets (GO or F-GO, respectively). A wide comparison with experimental data on both fluorinated and non-fluorinated membranes has been made. It was found that the expression employed for calculating the tortuosity factor of the model played an important role in whether the experimental data was accurately predicted. A modification of the tortuosity factor expression was proposed to enable the model to provide the best agreement between the experimental and theoretical values of proton conductivity. The results showed that in the case of fluorinated membranes at low amounts of GO or at high test temperatures the modified model was able to represent the experimental data more accurately than the original model. However, the selection of the best expression for the tortuosity factor calculations in non-fluorinated membrane systems depended on the ion exchange capacity values of the host membranes.     

Chemometrics-Enhanced Micelle-Mediated Extraction Spectrophotometric Method for Simultaneous Determination of Cu<Superscript>2+</Superscript> and Zn<Superscript>2+</Superscript> in Medicinal Plant,Rice and Water Samples Using Continuous Wavelet Transform

A new micelle-mediated extraction method for the pre-concentration of trace amounts of Cu²⁺ and Zn²⁺ as a prior step to their simultaneous spectrophotometric determination has been developed in various samples. The analytes were complexed with new synthesized ligand 4,4′-((4-chlorophenyl)methylene)bis(1,3-diphenyl-1H-pyrazol-5-ol) (CPBMPY) and Triton X-100 was added as a extraction agent. The optimal reaction and extraction conditions were optimized and the analytical characteristics of the method were obtained. The detection limit of the method was 0.90 and 0.30 ng mL^?1 for Cu²⁺ and Zn²⁺, respectively. Continuous wavelet transformation (CWT) of visible spectra as a very simple and accurate method was developed for the simultaneous determination of binary mixtures of Cu²⁺ and Zn²⁺ ions. A zero-crossing technique was applied on the transformed signals and the constructed calibrations were tested by analyzing the composition of the different binary mixtures. The proposed procedure successfully was applied to analysis of water, rice, and medicinal plant and reference material samples. The amounts of metal ions obtained by the proposed methods were in good agreement with those obtained by Graphite furnace atomic absorption spectrometry.     

Sensitivity and specificity of a short questionnaire for food insecurity surveillance in Iran

BACKGROUND: Food insecurity is frequent in both developed and developing countries, affecting from 5% to 25% of the general population. It has considerable health impacts on the physical, social, and psychological status of individuals in communities suffering from food insecurity. OBJECTIVE: The aim of this study was to document the epidemiologic features of food insecurity in the northwest region of Iran and to evaluate the sensitivity and specificity of a short-form (six items) questionnaire for screening of food insecurity in the region. METHODS: This cross-sectional study was conducted on 300 subjects (132 male and 168 female) selected randomly in the Asadabadi area of the northwest of Iran. Information on food consumption was obtained by a 24-hour food-recall questionnaire for 3 days in a week. This information was compared with the data from the Household Food Security Scale (six-item short questionnaire) to assess the applicability of this short scale for the surveillance of food insecurity. Hunger was defined as inadequate intake of energy. Hidden hunger was defined as adequate intake of energy and inadequate intake of one (or more) of four key nutrients (protein, calcium, vitamin A, and vitamin B2). RESULTS: The prevalence of hunger and hidden hunger in the area according to the 24-hour food-recall questionnaire was 26% and 42%, respectively. Only 32% of the study population was secure in terms of having access to all key nutrients. The sensitivity, specificity, and accuracy of the short questionnaire for screening for hunger in the population were 98.7%, 85.5%, and 89%, respectively; and the corresponding values for hidden hunger were 23.5%, 96.9%, and 56.3%. CONCLUSIONS: Our findings indicate that food insecurity is prevalent in the northwest of Iran. The short questionnaire (six items) may be used as a simple, low-cost, rapid, and useful tool for the screening of food insecurity and energy intake in similar areas.     

Novel predictive tools for design of radiant and convective sections of direct fired heaters

Direct fired heaters are used considerably in the energy related industries and petroleum industries for heating crude oil in the petroleum refining and petrochemical sectors. The aim of the current study is to formulate simple-to-use correlations to design the radiant and convective sections of direct fired heaters. The developed tools are easier than currently available models and involves a fewer number of parameters, requiring less complicated and shorter computations. Firstly, a simple correlation is developed to provide an accurate and rapid prediction of the absorbed heat in the radiant section of a fired heater, expressed as a fraction of the total net heat liberation, in terms of the average heat flux to the tubes, the arrangement of the tubes (circumferential), and the air to fuel mass ratio. Secondly, another simple correlation is developed to approximate external heat transfer coefficients for 75, 100, and 150 mm nominal pipe size (NPS) steel pipes arranged in staggered rows and surrounded by combustion gases. Finally, a simple correlation is presented to predict the gross thermal efficiency as a function of percent excess air and stack gas temperature. This study shows that the proposed method has a good agreement with the available reliable data in the literature. The average absolute deviations between reported data and the proposed correlations are found to be around 1.5% demonstrating the excellent performance of proposed predictive tool. The proposed simple-to-use method can be of significant practical value for the engineers and scientists to have a quick check on the design of radiant and convective sections of direct fired heater. In particular, mechanical and process engineers would find the proposed approach to be user-friendly involving no complex expressions with transparent and easy to understand calculations.     

Performance and carbon deposition over Pd nanoparticle catalyst promoted Ni/GDC anode of SOFCs in methane,methanol and ethanol fuels

The electrochemical performance and carbon deposition on palladium catalyst promoted Ni/Gd_0.1C_0.9O_1.95 (Ni/GDC) anode in methane and alcohol fuels like methanol and ethanol are investigated at open circuit potential and under dc bias using electrochemical impedance spectroscopy technique. Presence of Pd nanoparticle catalyst significantly promotes the electrocatalytic activity of Ni/GDC for the electrooxidation reaction in methane and in particularly in methanol and ethanol fuels. For instance, in the case of methanol oxidation reaction, there is clear separation of the impedance arcs at high and low frequencies and activation energy for the reaction is reduced by ∼33% on a 0.15 mg cm⁻² PdO impregnated or infiltrated Ni/GDC anode. The transitional impedance response study when the inlet gas is switched from hydrogen to methane or alcohol fuels indicates that the oxidation reaction in methane and alcohol fuels is most likely dominated by adsorption, dissociation and diffusion steps of the reaction. Carbon deposition is also observed on Pd-infiltrated Ni/GDC in methanol and ethanol, but different from that observed in methane, there is no filament carbon fibers formation on the Pd-impregnated Ni/GDC surface in methanol fuel.     

Prediction of compressed air transport properties at elevated pressures and high temperatures using simple method

Compressed air energy storage is a way to store energy generated at one time for use at another time. At utility scale, energy generated during periods of low energy demand can be released to meet higher demand periods. Also compressed air is a commonly used utility across most manufacturing and processing industries as its production and handling are safe and easy. Compressed air systems are critical and play a pivotal role in the proper operation of many processing facilities since most of the instruments and controls depend on pressurized instrumentation air for operation. In this work, a simple predictive tool, which is easier than current available models involving a large number of parameters, requiring more complicated and longer computations, is presented here for the prediction of transport properties (namely thermal conductivity and viscosity) of compressed air at elevated pressures as a function of temperature and pressure using a simple Arrhenius-type function. The proposed correlation predicts the transport properties of air for temperature range between 260 and 1000 K, and pressures up to 1000 bar (100 MPa). Estimations are found to be in excellent agreement with the reliable data in the literature with average absolute deviation being around 1.28% and 0.68% for thermal conductivity and viscosity respectively.     

Predictive tool for estimation of convection heat transfer coefficients and efficiencies for finned tubular sections

Fins or extended surfaces are widely used to increase the air side heat transfer rate in various heat exchange applications. In this paper, firstly, an attempt has been made to formulate a novel and simple-to-use correlation for the prediction of efficiencies for uniform thickness finned tubular sections as well as fin tip temperature for wide range of conditions (covering finned pipe diameter to pipe diameter ratios of up to 3). Secondly, another simple correlation is developed to approximate external convection heat transfer coefficients for nominal pipe size (NPS) steel pipes of 75, 100, and 150 mm arranged in staggered rows surrounded by combustion gases for temperature up to 600 °C and gas mass flow rates of up to 3 kg/(m² s). A simple interpolation formula generalizes this correlation for wide range of steel pipes. Average absolute deviations between the reported data and the proposed correlations are found to be around 1% demonstrating the excellent performance of proposed correlation. The tool developed in this study can be of immense practical value for engineers and scientists to have a quick check on the efficiencies for uniform thickness finned tubular sections as well as external convection heat transfer coefficients for various steel pipes arranged in staggered rows and surrounded by combustion gases flowing externally to heat a liquid in a pipe at various conditions without opting for any experimental measurements. In particular, practice engineers would find the predictive tool to be user-friendly with transparent calculations involving no complex expressions.