A Two‐Sided Cumulative Sum Chart for First‐Order Integer‐Valued Autoregressive Processes of Poisson Counts

Count data processes are often encountered in manufacturing and service industries. To describe the autocorrelation structure of such processes, a Poisson integer‐valued autoregressive model of order 1, namely, Poisson INAR(1) model, might be used. In this study, we propose a two‐sided cumulative sum control chart for monitoring Poisson INAR(1) processes with the aim of detecting changes in the process mean in both positive and negative directions. A trivariate Markov chain approach is developed for exact evaluation of the ARL performance of the chart in addition to a computationally efficient approximation based on bivariate Markov chains. The design of the chart for an ARL‐unbiased performance and the analyses of the out‐of‐control performances are discussed. Copyright © 2012 John Wiley & Sons, Ltd.     

Assessing the benefits of remanufacturing option under one-way substitution and capacity constraint

In this article, we investigate the profitability of remanufacturing option when the manufactured and remanufactured products are segmented to different markets and the production capacity is finite. A single period profit model under substitution is constructed to investigate the system conditions under which remanufacturing is profitable. We present analytical findings and computational results to show profitability of remanufacturing option under substitution policy subject to a capacity constraint of the joint manufacturing/remanufacturing facility.     

A pre-feasibility case study on integrated resource planning including renewables

In recent years, economical and environmental constraints force governments and energy policy decision-makers to change the prominent characteristics of the electricity markets. Accordingly, depending on local conditions on the demand side, usage of integrated resource planning approaches in conjunction with renewable technologies has gained more importance. In this respect, an integrated resource planning option, which includes the design and optimization of grid-connected renewable energy plants, should be evaluated to facilitate a cost-effective and green solution to a sustainable future.     

Right intra-atrial catheter placement for hemodialysis in patients with multiple venous failure

The purpose of this study is to evaluate the efficacy and safety of direct right atrial catheter insertion for hemodialysis in patients with multiple venous access failure. We retrospectively evaluated the charts of 27 patients with multiple venous access failure who had intra-atrial dialysis catheter placement between October 2005 and October 2010 in our clinic. Permanent right atrial dialysis catheters were placed through a right anterior mini-thoracotomy under intratracheal general anesthesia in all patients. Demographics of the cases, the patency rates of hemodialysis via atrial catheterization, existence of any catheter thrombosis, and catheter-related infections were documented and used in statistical analysis. Seventeen women (63%) and 10 men (37%) with the mean age of 59.0 ± 7.1 years (47-71) were enrolled in this study. Chronic renal failure was diagnosed for the mean of 78.9 ± 24.3 months (33-130). Five patients (18.5%) died. Ventricular fibrillation and myocardial infarction were the causes of death in the early postoperative period in two patients. Two of the remaining three patients died because of cerebrovascular events, and one patient died because of an unknown cause. Ten patients (37%) had been using anticoagulate agents (warfarin) because of concomitant disorders such as deep vein thrombosis, operated valve disease, and arrhythmias. Catheter thrombosis and malfunction was determined in three cases (11.1%). Intra-atrial hemodialysis catheterization is a safe and effective life-saving measure for the patients with multiple venous failure and without any possibility of peritoneal dialysis or renal transplantation.     

Optimization of temperature and light intensity for improved photofermentative hydrogen production using Rhodobacter capsulatus DSM 1710

Photofermentative hydrogen production is influenced by several parameters, including feed composition, pH levels, temperature and light intensity. In this study, experimental results obtained from batch cultures of Rhodobacter capsulatus DSM 1710 were analyzed to locate the maximum levels for the rate and yield of hydrogen production with respect to temperature and light intensity. For this purpose, a 3^k general full factorial design was employed, using temperatures of 20, 30 and 38 °C and light intensities of 100, 200 and 340 W/m². ANOVA results confirmed that these two parameters significantly affect hydrogen production. Surface and contour plots of the regression models revealed a maximum hydrogen production rate of 0.566 mmol H₂/L/h at 27.5 °C and 287 W/m² and a maximum hydrogen yield of 0.326 mol H₂/mol substrate at 26.8 °C and 285 W/m². Validation experiments at the calculated optima supported these findings.     

In situ modification of cyclohexanone formaldehyde resin with boric acid for high‐performance applications

A boron‐containing cyclohexanone formaldehyde resin (BCFR) was synthesized from cyclohexanone, formaldehyde, and boric acid. The effects of the boric acid concentration, solubility, molecular weight, and thermal properties on the product were investigated. Characterization of the BCFRs was done by NMR spectroscopy, gel permeation chromatography, and Fourier transform infrared–attenuated total reflectance spectroscopy. The thermal properties of the samples were determined with differential scanning calorimetry and thermogravimetric analysis. The study results demonstrate that the resin had higher heat‐resistance properties than the commonly modified cyclohexanone formaldehyde resin. The obtained samples were also characterized morphologically by scanning electron microscopy. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

A Simple and Green Route for Room‐Temperature Synthesis of Gold Nanoparticles and Selective Colorimetric Detection of Cysteine

Gold nanoparticles (AuNPs) were synthesized at room temperature following a simple, rapid, and green route using fresh‐squeezed apple juice as a reducing reagent. The optimal AuNPs, based on the particle color, stability, and color change suitable for colorimetric detection of cysteine (Cys), are synthesized using 5 mL of 10% apple juice, 1 mL of 10 mM gold precursor solution, and 1 mL of 0.1 M NaOH. Under this set of parameters, the AuNPs are synthesized within 30 min at room temperature. The average size (11.1 ± 3.2 nm) and ζ potential (–36.5 mV) of the AuNPs synthesized were similar to those of AuNPs prepared via the conventional citrate‐reduction method. In the presence of Cys, unlike with any other amino acid, the AuNPs aggregated, possibly due to the gold–sulfur covalent interaction, yielding red‐to‐purple color change of the sample solution. The red‐shift of the localized surface plasmon resonance peak of the AuNPs responsible for the color change was recorded by UV‐vis spectrometer. The effect of other potential interferents such as glucose, ascorbic acid, K⁺, Na⁺, Ca²⁺, Zn²⁺, Ag⁺, Ni²⁺, Cu²⁺, Co²⁺, and Hg²⁺ were also examined. The results show that AuNPs can be used to selectively detect and measure Cys with a linear dependency in the range of 2 to 100 μM and a limit of detection (signal‐to‐noise ratio > 3) of 50 nM. The results suggest that the green‐synthesized AuNPs are useful for simple, rapid, and sensitive colorimetric detection of Cys, which is an essential amino acid in food and biological systems.     

Aqueous solubility and alkaline hydrolysis of the novel high explosive hexanitrohexaazaisowurtzitane (CL-20)

The recently developed polycyclic nitramine CL-20 is considered as a possible replacement for the monocyclic nitramines RDX and HMX. The present study reports aqueous solubility data for CL-20, as well as the kinetic parameters for its alkaline hydrolysis with sodium hydroxide below and above its solubility limits. Aqueous solubility of CL-20 was measured in the temperature range of 4–69 °C and the data were fitted to a generalized solubility model. Alkaline hydrolysis experiments were conducted at 15, 20, 30 and 40 °C, with hydroxide concentrations ranging from 0.25 to 300 mM. Like RDX and HMX, alkaline hydrolysis of CL-20 follows second-order kinetics. CL-20 alkaline hydrolysis was found to proceed at a significantly faster rate than RDX. The temperature dependency of the second-order rate constants was evaluated using the Arrhenius model. The activation energy for CL-20 was found to be within close range of the activation energies reported for RDX and HMX.