Studying key users’ skills of ERP system through a comprehensive skill measurement model

Given to the significant role of enterprise resource planning systems (ERP) in the current organizations, several studies have been accomplished regarding these systems. The Main reason for the present research is having a small share in enhancement of success rate of ERP systems implementation through an applied study. In this study two purposes are pursued. First, this article intends to determine the most important skills required by key users (Also called power users and super users.) of ERP system as one of the most major members of ERP implementation team. Another purpose is to examine the skills shortages of these users in organizations under study and both of these purposes are obtained based on a comprehensive model. This research includes two major parts. First, based on experts’ opinion, a model is developed to determine and measure required technical, human, and conceptual skills as well as skills shortages of those involved in ERP implementation such as key users. Then, in second part, based on the above model and by means of a field study and studying thirteen Iranian organizations, the desirable amount (Amount of skill that key users expected to have.) and existing amount (Amount of skill that key users have at present.) of skills of key users are measured in each one of the technical, human, and conceptual categories. Then in order to determine and evaluate skill shortages, the difference between these two amounts in each category is examined. In this paper, human and conceptual skills are determined as the most important skills of key users in ERP implementation. Also, results confirm that key users have skills shortages in three kinds of main skills (i.e., technical, human, and conceptual) in the organizations under study. Moreover, key users in large companies suffer more from skills shortages than ones in SMEs.     

Electrochemical study of 1,2-dihydropyridazine-3,6-dione in protic and aprotic solvents: Oxidative ring cleavage and reduction

The electrochemical behavior of 1,2-dihydropyridazine-3,6-dione (3,6-dihydroxypyridazine) on glassy carbon electrode in aqueous and some organic solvents was investigated. The results indicate that the electrochemically generated pyridazine-3,6-dione is unstable and via oxidative ring cleavage converts to maleic acid. Also, the results show that the rate of oxidative ring cleavage depends on electrolysis media. In addition, the observed homogeneous rate constant of oxidative ring cleavage of 1,2-dihydropyridazine-3,6-dione was estimated by comparing the experimental cyclic voltammetric responses with the digital simulated results in aprotic solvents. Furthermore, some kinetic parameters related to irreversible cathodic electron transfer process of 1,2-dihydropyridazine-3,6-dione was estimated in aqueous solutions.     

Study on thermal stability of polyurethane-urea based on polysiloxane and polycaprolactone diols

Different grades of segmented polyurethane-urea were synthesized through two-step solution polymerization of polydimethylsiloxane (PDMS) and polycaprolactone (PCL) polyols with methylene diphenyl diisocyanate (MDI) and mixture of 1,4-buthanediol and 4,4-methylene bis (3-chloro 2,6-diethylaniline) in toluene/tetra-hydrofuran media. Structural characterization of the synthesized samples was conducted using Fourier transform infra-red spectroscopy. X-ray diffraction, dynamic mechanical thermal analysis, thermal gravimetric analysis, and differential scanning calorimetry techniques were utilized to assess material characteristics. The results showed a relationship between PDMS content and thermal stability, morphology and mechanical properties of the urethane-urea samples. Onset degradation temperature was increased by increasing the PDMS content in the polyurethane backbone where the crystallinity was varied versus PDMS content. Strong interaction established between hard and soft segments resulted in a positive shift in PCL glass transition temperature. Tracking E′, E″ and damping factor in DMTA measurements confirmed the two-phase morphology. Hydrophobicity of polymer surfaces was traced by contact angle measurement.     

The modified couple stress functionally graded cylindrical thin shell formulation

In this article, the functionally graded (FG) cylindrical thin shell formulation is developed by using modified couple stress theory. The equations of motion and classical and nonclassical boundary conditions are extracted based on Hamilton's principle. As a special case, the equations of motion in conjunction with the boundary conditions for simply supported FG cylindrical shell are obtained, and then Navier solution procedure is used for analysis free vibration of nano shell. Afterwards, the influences of different parameters like length scale parameter, distribution of FG properties, and length to radius ratio on dimensionless natural frequency are investigated and compared with classical theory.     

Modelling and optimization of a bi-objective flow shop scheduling with diverse maintenance requirements

In real-world problems, machines cannot continuously operate and have to stop for maintenance before they fail. Lack of maintenance can also affect the performance of machines in processing jobs. In this paper, a permutation flow shop scheduling problem with multiple age-based maintenance requirements is modelled as a novel mixed-integer linear program in which the objectives are conflicting. In modelling the problem, we assume that infrequent maintenance can prolong job processing times. One of the objectives is to minimise the total maintenance cost by planning as few maintenance activities as possible to only meet the minimum requirements, and the other objective tries to minimise the total tardiness by sequencing the jobs and planning the maintenance activities in such a way that the processing times are not prolonged and unnecessary maintenance times are avoided. Because of this conflict, an interactive fuzzy, bi-objective model is introduced. Application of the model is illustrated through a case study for operations and maintenance scheduling of heavy construction machinery. An effective and efficient solution methodology is developed based on the structure of the problem and tested against commercial solvers and a standard GA. Computational results have verified the efficiency of the proposed solution methodology and show that unlike the proposed method, a generic metaheuristic that does not consider the unique structure of the problem can become ineffective for real-world problem sizes.     

Engineering of the Electron Transport Layer/Perovskite Interface in Solar Cells Designed on TiO2 Rutile Nanorods

The engineering of the electron transport layer (ETL)/light absorber interface is explored in perovskite solar cells. Single‐crystalline TiO₂ nanorod (NR) arrays are used as ETL and methylammonium lead iodide (MAPI) as light absorber. A dual ETL surface modification is investigated, namely by a TiCl₄ treatment combined with a subsequent PC₆₁BM monolayer deposition, and the effects on the device photovoltaic performance were evaluated with respect to single modifications. Under optimized conditions, for the combined treatment synergistic effects are observed that lead to remarkable enhancements in cell efficiency, from 14.2% to 19.5%, and to suppression of hysteresis. The devices show J_SC, V_OC, and fill factor as high as 23.2 mA cm^?2, 1.1 V, and 77%, respectively. These results are ascribed to a more efficient charge transfer across the ETL/perovskite interface, which originates from the passivation of defects and trap states at the ETL surface. To the best of our knowledge, this is the highest cell performance ever reported for TiO₂ NR‐based solar cells fabricated with conventional MAPI light absorber. Perspective wise, this ETL surface functionalization approach combined with more recently developed and better performing light absorbers, such as mixed cation/anion hybrid perovskite materials, is expected to provide further performance enhancements.     

Controlling nanostructure in thermal plasma processing: Moving from highly aggregated porous structure to spherical silica nanoparticles

The synthesis of SiO₂ nanoparticles in a radio frequency (RF) plasma reactor is studied. Scanning electron microscopy (SEM), nitrogen absorption (BET), and laser diffractometry techniques are used to determine the morphology, product size and aggregation level of the resulting nanopowder. Computational fluid dynamics (CFD) modelling employing Fluent 6.2.16 is used to better understand the flow and temperature fields inside the reactor and their effect on the nanoparticles. The theoretical and experimental results are later combined to describe the effects of the above mentioned parameters on the formation (nucleation and growth) of the nanoparticles by different mechanisms. It is demonstrated that the quench gas configuration and reactor geometry can now be designed to control the morphology and size of nanoparticles in these reactors. Various nanostructured products have been synthesised: i.e., highly aggregated nanostructure, partially sintered nanospheres and spherical nanoparticles with very low levels of aggregation. These nanostructures have their primary particles sized between 10 and 200 nm, while the aggregate sizes can lie in the range of between hundreds of nanometers to several micrometers. The critical parameters that should be considered for the large-scale production process are finally identified.     

Spray Pyrolysis Deposition of ZnO Thin Films from Zinc Chloride Precursor Solution at Different Substrate Temperatures

ZnO films were prepared at different substrate temperatures through spraying pyrolysis deposition of zinc chloride precursor onto glass substrate. Substrate temperature affects surface morphology of films and therefore their optical and electrical properties. All films are polycrystalline with Wurtzite crystal structure and preferentially grow along c-axis direction. Formation of ZnO rods start at about 500 °C. The diameter and length of rods deposited at 500 °C are350–500 and 550–700 nm, respectively. By increasing substrate temperature, film becomes more coverage and diameter of the rods reduces to 250–300 nm but their length increases to 1,000–1,200 nm, respectively. Optical transmission in visible region decreases with increasing substrate temperature. An ultraviolet emission and two visible emissions at 2.82 and2.37 eV are observed for photoluminescence spectra at room temperature. The resistivity of ZnO films increases with increasing substrate temperature due to surface morphology.