Workforce planning and deployment for a hospital reservation call center with abandonment cost and multiple tasks

We consider a hospital reservation call center where operators handle multiple tasks. We take into account operator labor costs, caller waiting costs, and abandonment costs for lost calls. Instead of relying on the traditional method of queueing theory for call center management, we present a method that obtains expected caller waiting time and expected abandonment rate directly by introducing the inbound-load parameter. We develop a framework that combines workforce planning and operator deployment for a mixed call center in a single mathematical programming model. This paper also demonstrates how the proposed methodology can be applied in practice, with a case study based on actual operational data. Our primary conclusion is that the method presented in this research can significantly reduce both expected total cost (by 55.1% in our case study) and abandonment rate (from 15% to 2.1% in our case study). In addition, we demonstrate, using a sensitivity analysis, that our methodology will be more effective in an environment where the unit penalty cost of an abandoned call is relatively high among competitive hospitals.     

Finite element modeling of the human cervical spinal column: Role of the uncovertebral joint

Journal of Mechanical Science and Technology - The cervical intervertebral disc has a unique feature in that a fissure or cleft runs along the uncinate process toward the nucleus pulposus called...     

Potential Chemical Markers for the Identification of Irradiated Sausages

Abstract: Hydrocarbons, gas compounds, and off‐odor volatiles were determined for irradiated (0 or 5 kGy) commercial sausages with different fat contents (16% and 29%) during a 60‐d storage period at 4 °C. Total of 4 hydrocarbons (C14:1, C15:0, C16:2, and C17:1) were detected only in irradiated sausages: the amount of C16:2 was the highest, followed by C17:1, C14:1, and C15:0. The concentrations of hydrocarbons decreased significantly (P < 0.05) with storage, but were still detectable at the end of 60‐d storage. Irradiated sausages produced significantly higher amounts of CO than the nonirradiated ones. CH₄ was detected only in irradiated sausages. Dimethyl disulfide was detected only in irradiated sausages and its concentration decreased significantly (P < 0.05) with storage. Fat content of sausages showed a significant effect on the production and retention of hydrocarbons, gas compounds, and sulfur volatiles in irradiated sausages during storage. Some hydrocarbons (C16:2, C17:1, C14:1, and C15:0), CH₄, and dimethyl disulfide were only found in irradiated sausages indicating that these compounds can be used as potential markers for irradiated sausages.     

Analysis of ethanol in soy sauce using electronic nose for halal food certification

The purpose of this study was to analyze ethanol content in soy sauce using mass spectrometry (MS) with electronic nose (e-nose) to determine if MS e-nose can replace gas chromatographic analysis for halal certification. Gas chromatography–flame ionization detector (GC-FID), the standard method of ethanol content, was used to analyze 24 different kinds of soy sauce. Ethanol was detected from 13 soy sauce samples in the concentration range of 0.0004–1.7wt%. The MS e-nose data were analyzed by discriminant function analysis (DFA). Based on an addition method, the results were more than 96.6% accurate when the ethanol concentrations were greater than 0.5%. A high correlation between the first score of the DFA plot and the ethanol concentration was observed. Thus, mass spectrometry based on e-nose is an efficient method for determining ethanol as a primary screening tool for halal certification.     

Modeling Water Flow Through Carbon Nanotube Membranes with Entrance/Exit Effects

Carbon nanotube–based membranes have gained significant attention due to their transport efficiency and wide range of applications, including molecular sieving and sensing. Recently, in order to attain high transport rates, many studies have focused on reducing membrane thickness. A reduction in membrane thickness results in the dominance of entrance/exit effects over surface effects, particularly for carbon nanotubes (CNTs), due to their hydrophobicity. However, experimentally obtained nanoscale flow rate data span a wide range, and entrance/exit effects are often neglected when analyzing these data. In this study, we modeled the water flow rate through various lengths and radii of CNTs using molecular dynamics simulations while also taking entrance/exit effects into consideration. Based on viscosity and slip length calculations, a water flow model is proposed that covers various lengths and radii of CNTs. Moreover, the enhancement factor of CNT membranes is reassessed using entrance/exit effects. The results of this study can be used for the optimal design of ultraefficient CNT membranes for potential applications such as water filtration.     

Optical properties of TiO2 nanorods modified by electron-donating stabilizers

A significant change in the UV-vis absorption of TiO₂ nanorods (NRs) was induced by changing electrondonating stabilizer from oleic acid (OA) to acrylic acid (AcA). When TiO₂ NRs with an average size of 2.5 nm in diameter and 30 nm in length were dispersed in an aqueous AcA solution, a red shift in the optical absorption (0.73 eV at the band edge and 0.55 eV at the onset) was observed. The red shift was attributed to an increase in the electron density inside the TiO₂ NRs. The applicability of the AcA-exchanged TiO₂ NRs for the photocatalyst as well as a UV sensor was evaluated. The AcA-exchanged TiO₂ NRs showed significant photocatalytic activity on the degradation of toluene in the visible light region. Moreover, thin film of the AcA-exchanged TiO₂ NRs on a quartz plate was tested as a UV sensor and it exhibited a good response to a wide range of the UV light.     

Recycling of LiCl–KCl eutectic based salt wastes containing radioactive rare earth oxychlorides or oxides

Recycling of LiCl–KCl eutectic salt wastes containing radioactive rare earth oxychlorides or oxides was studied to recover renewable salts from the salt wastes and to minimize the radioactive wastes by using a vacuum distillation method. Vaporization of the LiCl–KCl eutectic salt was effective above 900 °C and at 5 Torr. The condensations of the vaporized salt were largely dependent on temperature gradient. Based on these results, a recycling system of the salt wastes as a closed loop type was developed to obtain a high efficiency of the salt recovery condition. In this system, it was confirmed that renewable salt was recovered at more than 99 wt.% from the salt wastes, and the changes in temperature and pressure in the system could be utilized to understand the present condition of the system operation.     

Development of an Automated Method for Folin‐Ciocalteu Total Phenolic Assay in Artichoke Extracts

Abstract: We developed a system to run the Folin‐Ciocalteu (F‐C) total phenolic assay, in artichoke extract samples, which is fully automatic, consistent, and fast. The system uses 2 high performance liquid chromatography (HPLC) pumps, an autosampler, a column heater, a UV/Vis detector, and a data collection system. To test the system, a pump delivered 10‐fold diluted F‐C reagent solution at a rate of 0.7 mL/min, and 0.4 g/mL sodium carbonate at a rate of 2.1 mL/min. The autosampler injected 10 μL per 1.2 min, which was mixed with the F‐C reagent and heated to 65 °C while it passed through the column heater. The heated reactant was mixed with sodium carbonate and color intensity was measured by the detector at 600 nm. The data collection system recorded the color intensity, and peak area of each sample was calculated as the concentration of the total phenolic content, expressed in μg/mL as either chlorogenic acid or gallic acid. This new method had superb repeatability (0.7% CV) and a high correlation with both the manual method (r²= 0.93) and the HPLC method (r²= 0.78). Ascorbic acid and quercetin showed variable antioxidant activity, but sugars did not. This method can be efficiently applied to research that needs to test many numbers of antioxidant capacity samples with speed and accuracy.     

Failure analysis of Cu(In,Ga)Se2 photovoltaic modules: degradation mechanism of Cu(In,Ga)Se2 solar cells under harsh environmental conditions

High‐temperature‐induced and humidity‐induced degradation behaviors were investigated through the failure analysis of encapsulated Cu(In,Ga)Se₂ (CIGS) modules and non‐encapsulated CIGS cells. After being exposed to high temperature (85 °C) for 1000 h, the efficiency loss of CIGS modules and the resistivities of the aluminum‐doped zinc oxide (AZO) layer, CIGS layer, and Mo layer were slightly increased. After damp heat (DH) testing (85 °C/85% RH), the efficiency of some modules decreased significantly accompanied by discoloration, and in these areas, the resistivity of the AZO layers increased markedly. The causes of degradation of CIGS cells after high temperature and DH tests were suggested through X‐ray photoelectron spectroscopy analysis. The high‐temperature‐induced degradation behaviors were revealed to be increases in series resistance of the CIGS cells, due to the adsorption of oxygen on the AZO, CIGS, and Mo layers. The degradation behavior after DH (85 °C/85% RH) exposure was caused by the adsorption of oxygen, as well as the generation of Zn(OH)₂ due to water molecules. In particular, the humidity‐induced degradation behavior in discolored CIGS modules was ascribed to the generation of Zn(OH)₂ and carboxylic acids in the AZO layer, due to a chemical reaction between the AZO, ethylene‐vinyl acetate copolymer, and water. Copyright © 2014 John Wiley & Sons, Ltd.     

Inserting polyoxomolybdate cluster into poly(?-caprolactone) to create a class of new heteropolymer: Synthesis and supramolecular structures

In the present work, we report our work concerning the synthesis of heteropolymers of poly(?-caprolactone)-polyoxomolybdate-poly(?-caprolactone) using ring-opening polymerization (ROP) of ?-caprolactone monomer initiated by two hydroxyl groups attached on the two sides of a polyoxomolybdate cluster which was organically modified using pentaerythritols. Since the hydroxyl groups on polyoxomolybdate macroinitiator are less reactive, ring-opening polymerization were finally carried out by using 4,4′-(dimethylamino) pyridine to activate ?-caprolactone monomer. The polyoxomolybdate-containing heteropolymers were confirmed in detail by ¹H NMR, FT-IR, GPC, TGA and XPS methods. Although the size of polyoxomolybdate cluster is extremely small compared to PCL chains, it was also found that POM played an important role in crystallization process. Self-assembly of such heteropolymers in mixed solvents were investigated and the analysis of formed spherical aggregates with multiple concaves on the surface was supported by TEM results and 3D electron tomography.