The use of participant-observation protocol in an industrial engineering research

Based on literature, this article aims to present the "participant-observation" research protocol, and its practical application in the industrial engineering field, more specifically within the area of design development, and in the case shown by this article, of interiors' design. The main target is to identify the concept of the method, i.e., from its characteristics to structure a general sense about the subject, so that the protocol can be used in different areas of knowledge, especially those ones which are committed with the scientific research involving the expertise from researchers, and subjective feelings and opinions of the users of an engineering product, and how this knowledge can be benefic for product design, contributing since the earliest stage of design.

Physico-chemical properties of Brazilian cocoa butter and industrial blends. Part II - Microstructure, polymorphic behavior and crystallization characteristics

The microstructural behavior of industrial standardized cocoa butter samples and cocoa butter samples from three different Brazilian states is compared. The cocoa butters were characterized by their microstructural patterns, crystallization kinetics and polymorphic habits. The evaluation of these parameters aided in establishing relationships between the chemical compositions and crystallization behavior of the samples, as well as differentiating them in terms of technological and industrial potential for use in tropical regions.

Integrated pulp and paper mill planning and scheduling

This article describes a real-world production planning and scheduling problem occurring at an integrated pulp and paper mill (P&P) which manufactures paper for cardboard out of produced pulp. During the cooking of wood chips in the digester, two by-products are produced: the pulp itself (virgin fibers) and the waste stream known as black liquor. The former is then mixed with recycled fibers and processed in a paper machine. Here, due to significant sequence-dependent setups in paper type changeovers, sizing and sequencing of lots have to be made simultaneously in order to efficiently use capacity. The latter is converted into electrical energy using a set of evaporators, recovery boilers and counter-pressure turbines. The planning challenge is then to synchronize the material flow as it moves through the pulp and paper mills, and energy plant, maximizing customer demand (as backlogging is allowed), and minimizing operation costs. Due to the intensive capital feature of P&P, the output of the digester must be maximized. As the production bottleneck is not fixed, to tackle this problem we propose a new model that integrates the critical production units associated to the pulp and paper mills, and energy plant for the first time. Simple stochastic mixed integer programming based local search heuristics are developed to obtain good feasible solutions for the problem. The benefits of integrating the three stages are discussed. The proposed approaches are tested on real-world data. Our work may help P&P companies to increase their competitiveness and reactiveness in dealing with demand pattern oscillations. (C) 2012 Elsevier Ltd. All rights reserved.

Physico-chemical properties of Brazilian cocoa butter and industrial blends. Part I - Chemical composition, solid fat content and consistency

A comparative study of the primary properties of six cocoa butter samples, representative of industrial blends and cocoa butter extracted from fruits cultivated in different geographical areas in Brazil is presented. The samples were evaluated according to fatty acid composition, triacylglycerol composition, regiospecific distribution, melting point, solid fat content and consistency. The results allowed for differentiating the samples according to their chemical compositions, thermal resistance properties, hardness characteristics, as well as technological adequacies and potential use in regions with tropical climates.

Understanding the mechanical and biodegradation behaviour of poly(hydroxybutyrate)/rubber blends in relation to their morphology

In this work poly(hydroxybutyrate/poly(vinyl butyral)- co-(vinyl alcohol)-co(vinyl acetate) (or ethylene propylene diene monomer rubber) blends were prepared by conventional processing techniques (extrusion and injection moulding). A droplet type morphology was obtained for P(3HB)/PVB blends whereas P(3HB)/EPDM blends presented some extent of co-continuous morphology. In addition, rubbery domains were much smaller in the case of PVB. These differences in morphology are discussed taking into account solubility parameters and rheological behaviours of each component. For both blends, the increase of elastomer ratio led to a decrease of Young's modulus but an increase in elongation at break and impact strength. The latter increased more in the case of P(3HB)/EPDM blends although the rubbery domains were larger. These results are explained in the light of the glass transition of the rubber and the presence of plasticizer in the case of PVB. The addition of elastomer also resulted in an increase of P(3HB) biodegradation rate, especially in the case of EPDM. It is assumed that, in this case, the size and morphology of the rubbery domains induce a geometrical modification of the erosion front which leads to an increase of the interface between P(3HB) phase and the degradation medium and consequently to an apparently faster biodegradation kinetics of PHB/rubber blends. Copyright (C) 2011 Society of Chemical Industry

Red Mud from Brazil: Thermal Behavior and Physical Properties

The main constituents of red mud produced in Aluminio city (S.P., Brazil) are iron, aluminum, and silicon oxides. It has been determined that the average particle diameter for this red mud is between 0.05 and 0.002 mm. It is observed that a decrease in the percentage of smaller particles occurs at temperatures greater than 400 degrees C. This observation corresponds with the thermal analysis and X-ray diffraction (XRD) data, which illustrate the phase transition of goethite to hematite. A 10% mass loss is observed in the thermal analysis patterns due to the hydroxide-oxide phase transitions of iron (primary phase transition) and aluminum (to a lesser extent). The disappearance and appearance of the different phases of iron and aluminum confirms the decomposition reactions proposed by the thermal analysis data. This Brazilian red mud has been classified as mesoporous at all temperatures except between 400 and 500 degrees C where the classification changes to micro/mesoporous.

Use of cellulose fibers from hemp core in fiber-cement production. Effect on flocculation, retention, drainage and product properties

The aim of this paper is to study the feasibility of using cellulose fibers obtained from an agricultural waste, hemp core (Cannabis Sativa L), through different new environmental friendly cooking processes for fiber-cement production. The physical and mechanical properties of the fiber reinforced concrete, which depend on the nature and morphology of the fibers, matrix properties and the interactions between them, must be kept between the limits required for its application. Therefore, the morphology of the fibers and how its use affects the flocculation, retention and drainage processes in the fiber-cement manufacture, and the mechanical and physical properties of the fiber-cement product have been studied. The use of pulp obtained by means of the hemp core cooking in ethanolamine at 60% concentration at 180 degrees C during 90 min resulted in the highest solids retention and the best mechanical properties among the studied hemp core pulps. (C) 2012 Elsevier B.V. All rights reserved.

Influence of Particle Size, Applied Compression, and Substratum Material on Particle-Surface Adhesion Force Using the Centrifuge Technique

The centrifuge technique was used to investigate the influence of particle size, applied compression, and substrate material (stainless steel, glass, Teflon, and poly(vinyl chloride)) on particle-surface adhesion force. For this purpose, phosphatic rock (rho(p) = 3090 kg/m(3)) and manioc starch particles (rho(p) = 1480 kg/m(3)) were used as test particles. A microcentrifuge that reached a maximum rotation speed of 14 000 rpm and which contained specially designed centrifuge tubes was used in the adhesion force measurements. The curves showed that the adhesion force profile followed a normal log distribution. The adhesion force increased linearly with particle size and with the increase of each increment of compression force. The manioc starch particles presented greater adhesion forces than the phosphatic rock particles for all particle sizes studied. The glass substrate showed a higher adherence than the other materials, probably due to its smoother topographic surface roughness in relation to the other substrata.

Polycyclic aromatic hydrocarbons (PAHs) in a large South American industrial coastal area (Santos Estuary, Southeastern Brazil): Sources and depositional history

Located in southeastern Brazil, the Santos Estuary has the most important industrial and urban population area of South America. Since the 1950`s, increased urbanization and industrialization near the estuary margins has caused the degradation of mangroves and has increased the discharge of sewage and industrial effluents. The main objectives of this work were to determine the concentrations and sources of polycyclic aromatic hydrocarbons (PAHs) in sediment cores in order to investigate the input of these substances in the last 50 years. The PAHs analyses indicated multiple sources of these compounds (oil and pyrolitic origin), basically anthropogenic contributions from biomass, coal and fossil fuels combustion. The distribution of PAHs in the cores was associated with the formation and development of Cubatao industrial complex and the Santos harbour, waste disposal, world oil crisis and the pollution control program, which results in the decrease of organic pollutants input in this area. (C) 2011 Elsevier Ltd. All rights reserved.

Two extensions for the ALWABP: Parallel stations and collaborative approach

In this article, we introduce two new variants of the Assembly Line Worker Assignment and Balancing Problem (ALWABP) that allow parallelization of and collaboration between heterogeneous workers. These new approaches suppose an additional level of complexity in the Line Design and Assignment process, but also higher flexibility; which may be particularly useful in practical situations where the aim is to progressively integrate slow or limited workers in conventional assembly lines. We present linear models and heuristic procedures for these two new problems. Computational results show the efficiency of the proposed approaches and the efficacy of the studied layouts in different situations. (C) 2012 Elsevier B.V. All rights reserved.

Synthesis of Carbon Nanomaterials through Up-Cycling Agricultural and Municipal Solid Wastes

This work addresses the synthesis of carbon nanomaterials (CNMs) by up-cycling common solid wastes. These feedstocks could supersede the use of costly and often toxic or highly flammable chemicals, such as hydrocarbon gases, carbon monoxide, and hydrogen, which are commonly used as feedstocks in current nanomanufacturing processes for CNMs. Agricultural sugar cane bagasse and corn residues, scrap tire chips, and postconsumer polyethylene (PE) and polyethylene terephthalate (PET) bottle shreddings were either thermally treated by sole pyrolysis or by sequential pyrolysis and partial oxidation. The resulting gaseous carbon-bearing effluents were then channeled into a heated reactor. CNMs, including carbon nanotubes, were catalytically synthesized therein on stainless steel meshes. This work revealed that the structure of the resulting CNMs is determined by the feedstock type, through the disparate mixtures of carbon-bearing gases generated when different feedstocks are pyrolyzed. CNM characterization was conducted by scanning and transmission electron microscopy as well as by Raman spectroscopy and by thermogravimetric analysis. Gas chromatography was used to characterize the gases in the synthesis chamber. This work demonstrated an alternative method for efficient manufacturing of CNMs using both biodegradable and nonbiodegradable agricultural and municipal carbonaceous wastes.

Development and Evaluation of a Pseudoreference Pt//Ag/AgCl Electrode for Electrochemical Systems

The use of standard reference electrodes, such as Ag/AgCl or saturated calomel electrodes, in potentiometric and amperometric studies involving miniaturized electrochemical systems, or those operating under positive hydraulic pressure, is often impractical. Placement of the reference electrode in the direct vicinity of the working electrode is often prohibited by the dimensions or layout of the electrochemical cell, while the alternative strategy of locating the reference electrode in a separate compartment often leads to electrolyte leakage and contamination of the system. In the present study, we have investigated the functionality of a pseudoreference electrode comprising a platinum wire, one end of which was maintained in intimate contact with the internal solution of an Ag/AgCl reference electrode while the other was connected, via a BNC connector, to a platinum probe located within the electrochemical cell. Linear and cyclic voltammetric studies, involving both aqueous and nonaqueous electrolytes, were carried out using the pseudoreference electrode and an electrochemical cup-type cell with three electrodes or an electrochemical flow reactor. In all cases, the functionality of the Pt//Ag/AgCl system was similar to that of a conventional Ag/AgCl reference electrode. Variations in the electrolyte did not alter the potential or voltammetric profile recorded when using the pseudoreference system, although peak currents were generally improved and potential values shifted by approximately +350 mV in comparison with the Ag/AgCl electrode, therefore, the system pseudoreference can be applied in any electrochemical system due to the constant potential difference. It is concluded that the pseudoreference electrode can be used with advantage to obtain potentiometric and amperometric measurements in both simple and complex electrochemical systems.

Chemical Modifications in Styrene-Butadiene Rubber after Microwave Devulcanization

Microwave devulcanization has been studied as a method for elastomer recycling, which is based on the conversion of the reticulated and infusible structure of thermosetting rubbers in free polymeric chains able to be remolded by thermomechanical processing in recycling operations for the manufacture of other products. Elastomeric wastes are often irregularly discarded in nature, producing serious environmental damage, and their mechanical recycling is still considered a challenge. Thus, the development of alternatives for elastomer recycling is directly related to the actions of sustainable development and economic benefits to companies that pay to discard their wastes. The aim of this work is to evaluate the chemical modifications occurring in styrene butadiene rubber (SBR) after microwave devulcanization. Compounds of SBR were vulcanized in the presence of vulcanization agents and variable amounts of carbon black, and then the rubbers were milled and submitted to microwave treatment. Only the SBR with high carbon black content shows some portion of devulcanized material. However, the rubber with lower content of carbon black which was devulcanized by microwave radiation shows an increase in cross-link density. The microwave treatment also causes cross-link breaks mainly in polysulfidic bonds as well as decomposition of chemical groups containing sulfur attached to the chemical structure of SBR, while. the chemical bonds of higher energy such as monosulfidic bonds remain preserved. The improvement of the microwave method for rubber devulcanization represents a way for viable recycling of thermosetting rubbers.

An Overview of Relevant Aspects on VIM of Spar and Monocolumn Platforms

Vortex-induced motions (VIM) of floating structures are very relevant for the design of mooring and riser systems. In the design phase, spar and monocolumn VIM behavior, as well as semisubmersible and tension leg platform flow-induced motions, is studied and evaluated. This paper provides a checklist of topics and evidence from a number of sources to justify the selection that should be considered when designing spars or monocolumn platforms regarding the VIM phenomenon. An overview of the influential aspects of the VIM is presented such as heading, external appendages of the hull, concomitant presence of waves and currents, motion suppressor, draft condition (immersed portion of the hull), and external damping due to the presence of risers. Previous works concerning the VIM studies on spar and monocolumn platforms are also addressed. Whenever possible, the results of experiments from diverse authors on this matter are presented and compared. [DOI: 10.1115/1.4003698]

Asynchronous teams for joint lot-sizing and scheduling problem in flow shops

The integrated production scheduling and lot-sizing problem in a flow shop environment consists of establishing production lot sizes and allocating machines to process them within a planning horizon in a production line with machines arranged in series. The problem considers that demands must be met without backlogging, the capacity of the machines must be respected, and machine setups are sequence-dependent and preserved between periods of the planning horizon. The objective is to determine a production schedule to minimise the setup, production and inventory costs. A mathematical model from the literature is presented, as well as procedures for obtaining feasible solutions. However, some of the procedures have difficulty in obtaining feasible solutions for large-sized problem instances. In addition, we address the problem using different versions of the Asynchronous Team (A-Team) approach. The procedures were compared with literature heuristics based on Mixed Integer Programming. The proposed A-Team procedures outperformed the literature heuristics, especially for large instances. The developed methodologies and the results obtained are presented.