Workflow technology-based monitoring and control for business process and project management

In this paper the application of workflow technology to monitor, control and coordinate business processes and projects is proposed. The conceptual characteristics of processes and projects as well as their management needs in the functions of planning, execution, monitoring and control are compared. The general design of the proposed system is then developed, with an application example. The proposed monitoring and control system provides proactive tracking of the flow of work and information, and of the utilization and commitment of resources. The design supports hierarchical management of the project and/or business process, allowing concerned persons to visualize and to utilize it in different levels of abstraction, as necessary. The application of workflow technology also provides additional benefits in facilitating communication, documentation and re-utilization.     

A Fast Method for Finding the Basis of Non-negative Solutions to a Linear Diophantine Equation

We present a complete characterization of the set of minimal solutions of a single linear Diophantine equation in three unknowns over the natural numbers. This characterization, for which we give a geometric interpretation, is based on well-known properties of congruences and we use it as the foundation of direct algorithms for solving this particular kind of equation. These direct algorithms and an enumeration procedure are then put together to build an algorithm for solving the general case of a Diophantine equation over the naturals. We also put forth a statistical method for comparing algorithms for solving Diophantine equations which is more sound than comparisons based on times observed for small sets of equations. From an extensive comparison with algorithms described by other authors it becomes clear that our algorithm is the fastest known to date for a class of equations. Typically the equations in this class have a small number of unknowns in one side, the maximum value for their coefficients being greater than 3.     

Utilization of electrochemical impedance spectroscopy for monitoring bornite (Cu5FeS4) oxidation by Acidithiobacillus ferrooxidans

In this work, the monitoring of the bacterial and chemical dissolution of bornite was evaluated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS); the mineral surface was examined using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The analysis of CV results allowed attributing the different peaks observed in both direct and reverse potential scanning to the oxidation of bornite to a secondary covellite and its reduction via different non stoichiometric copper sulphides intermediaries. EIS data for bornite were obtained in control medium up to 78 h of immersion, when a cellular suspension of A. ferrooxidans was added and the experiments continued up to a 192 h of test. The EIS response was different when bacteria were added in the beginning of the test or after some hours of immersion in acid solution. The experiments were performed in different cell configurations and a model of the electrode/electrolyte interface. The correspondent equivalent electrical circuit was used to fit impedance spectra for all studied conditions. A common equivalent circuit used for corrosion processes where anodic (degradation of the mineral) and cathodic (oxygen reduction) reactions occur in parallel, together film and biofilm formation was proposed.     

Biphasic α2β1 Integrin Expression in Breast Cancer Metastasis to Bone

Integrins participate in the pathogenesis and progression of tumors at many stages during the metastatic cascade. However, current evidence for the role of integrins in breast cancer progression is contradictory and seems to be dependent on tumor stage, differentiation status, and microenvironmental influences. While some studies suggest that loss of α2β1 enhances cancer metastasis, other studies suggest that this integrin is pro-tumorigenic. However, few studies have looked at α2β1 in the context of bone metastasis. In this study, we aimed to understand the role of α2β1 integrin in breast cancer metastasis to bone. To address this, we utilized in vivo models of breast cancer metastasis to bone using MDA-MB-231 cells transfected with an α2 expression plasmid (MDA-OEα2). MDA cells overexpressing the α2 integrin subunit had increased primary tumor growth and dissemination to bone but had no change in tumor establishment and bone destruction. Further in vitro analysis revealed that tumors in the bone have decreased α2β1 expression and increased osteolytic signaling compared to primary tumors. Taken together, these data suggest an inverse correlation between α2β1 expression and bone-metastatic potential. Inhibiting α2β1 expression may be beneficial to limit the expansion of primary tumors but could be harmful once tumors have established in bone.     

Use of a dispersed iron catalyst for upgrading extra-heavy crude oil using methane as source of hydrogen

The use of an iron dispersed catalyst, derived from Fe₃(CO)₁₂, for extra-heavy crude oil upgrading using methane as source of hydrogen was studied. The upgrading reactions were carried out batchwise in a stainless-steel 300 ml Parr reactor with 250 ppm of Fe at a temperature of 410-420 °C, a pressure of 11 MPa of CH₄, and a residence time of 1 h. In the presence of Fe₃(CO)₁₂, the reaction of Hamaca extra-heavy crude oil led to a reduction of two orders of magnitude in the viscosity (from 500 to 1.3 Pa s), 14% reduction in sulfur content, and 41% conversion of the >500 °C fraction in the upgraded product with respect to the original crude. The iron catalyst was isolated from the coke produced from the upgrading reaction and was analyzed by XPS, EDAX, and Mössbauer spectroscopy. The results indicated the presence of a Fe-V mixed sulfide species with a composition ca. (Fe_0.6V_0.4)_zS, where z is in the range 0.8-0.9.     

Discoloration process modeling by neural network

The photo-oxidation of acid orange 52 dye was performed in the presence of H₂O₂, utilizing UV light, aiming the discoloration process modeling and the process variable influence characterization. The discoloration process was modeled by the use of feedforward neural network. Each sample was characterized by five independent variables (dye concentration, pH, hydrogen peroxide volume, temperature and time of operation) and a dependent variable (absorbance). The neural model has also provided, through Garson Partition coefficients and the Pertubation method, the independent variable influence order determination. The results indicated that the time of operation was the predominant variable and reaction mean temperature was the lesser influent variable. The neural model obtained presented coefficients of correlation on the order 0.98, for sets of trainability, validation and testing, indicating the power of prediction of the model and its character of generalization.     

Two-step route polycondensation for polynaphthalimides synthesis through high molar mass soluble precursors: A kinetic study

Research of polynaphthalimides (PNI) frequently reports difficulties over synthesis and processing due to insolubility. In this work, we present a novel comprehensive study on the effects of time, temperature and catalyst on the synthesis of soluble PNI precursors—polyamic acids (PAAs)—, as well as a novel synthetic procedure for the synthesis of PNI using mild conditions. Kinetic studies concerning the monomer conversion and the degree of premature imidization were performed through proton nuclear magnetic resonance and gel permeation chromatography for temperature ranging from 25 to 100°C. High temperatures (above 60°C) entail extensive premature imidization and insolubility. The use of triethylamine also catalyzes imidization. At the optimal condition, soluble PAA precursors for PNI of 72 kDa could be obtained at 40°C in N-methyl-2-pyrrolidone solution (30 wt%) after 5 hr polymerization.     

Fracture toughness of high strength seamless pipe steel from SE(T) and SE(B) specimens evaluated by different standards

Recently released, BS 8571:2014 standard offers an alternative for the experimental determination of fracture toughness and resistance curves of metallic materials from SE(T) specimens. Similar in stress conditions and constraint to cracked tubes, specimens in SE(T) geometry should yield less conservative toughness values than conventional high‐constraint specimens, such as SE(B) geometry. However, the convention to determine the J‐integral fracture toughness proposed in the new BS standard is different from ASTM standards. In this work, SE(T) and SE(B) specimens of similar dimensions of a tough high‐strength seamless pipe steel were tested following the BS 8571:2014 and ASTM E1820‐16 standards, respectively. Because of the different standardized definitions, SE(T) specimens yield lower fracture toughness than SE(B) specimens, which could lead to more conservative results in structural integrity analysis. This investigation also suggests the introduction of the blunting line concept in the BS 8571:2014 standard in order to minimize this problem.