Advanced Aspects of Engineering Research Vol. 1

Rutting and fatigue cracking are key rheological and performance indicators employed in asphalt technology. The use of waste polymeric materials as modifiers for the improvement of performance of asphalt pavement material has been promising. The absence of studies investigating the influence of waste polystyrene (PS) on the performance characteristics of rutting resistance and fatigue cracking resistance of the indigenous asphaltic materials Trinidad Lake Asphalt (TLA) and Trinidad Petroleum Bitumen (TPB), has hindered the possible use of PS as a performance enhancer as observed with other asphalts from different sources thus also developing a sustainable approach for the disposal of PS. The influence of PS on TLA and TPB was investigated by measuring the rheological properties of complex modulus (G*) and phase angle (\(\delta\)) of prepared blends and calculating the fatigue cracking resistance and rutting resistance parameters (G*sin\(\delta\) and G*/sin\(\delta\) respectively). The addition of PS to TLA resulted in an increase in the fatigue cracking resistance as well as the rutting resistance compared to the pure TPB binder. Despite having improvements in rutting resistance due to PS addition, the fatigue cracking resistance of the TPB parent binders were superior compared with the PS modified TPB blends. The incremental increase in temperatures for TPB and TLA based blends resulted in gradual improvements in their fatigue cracking resistances but gradual deterioration in the rutting resistance of the modified blends. The conclusions were identical for both the Research Program Superpave specification and the Strategic Highway Research Program specifications. There is strong rheological evidence of the possibility to utilize waste PS as an asphalt performance enhancer for both TLA and TPB thus creating a sustainable strategy for the reuse of waste PS.

A representation scheme called CKR-1 is introduced to deal with the challenges of representing complex knowledge.  Complex knowledge is defined as deep knowledge concerning a complex object, event, situation or process.  The nature of complex knowledge is identified from samples of professional knowledge drawn from the insurance industry.  These examples highlight efficacy of the scheme as well as its limitations.  CKR-1 is a type of semantic network that supports simple and abstract concepts, events, activities and situations.  It also supports several types of relationships including business, logical, causal, process etc.  It derives its expressivity from ability to support abstractions, elaborations, assertions and alternative points of view.  Usability was tested with a randomized selection of fifty knowledge items from a book for insurance professionals.  The scheme handled 39 of these well.  Despite this, the scheme suffers from limitations stemming from the inherent difficulty in expressing concepts involving several other vaguely defined abstract concepts.  

Office Information Systems is a field of computer science concerned with studying offices and developing technologies to support office workers. The field initiated in 1982 suffered a gradual demise by 2004. However, many of the themes and issues that motivated the discipline continue to exist today. Office workers continue to struggle with routine tasks that do not have adequate IT support and the problem is worse for mobile employees. In this paper we provide a retrospective on OIS technologies with the hope of stimulating interest in this important area and addressing the needs of office workers worldwide. The evolution of office technologies and a detailed discussion of past research is provided. The discussion shows that technology support for office workers is still inadequate. The paper suggests a technology vision and architecture to motivate researchers and identifies challenges for future research.

The problems related to hydro-environmental engineering on small islands are flood and drought, for the less favorable rainfall characteristics. Big rainfall intensity comes and flows immediately as storm runoff to the sea because of short distance, and no chance to infiltrate into the soil as ground-water recharge. Floods and landslides occur during rainy season and drought during dry season. Managing rainwater is an action to direct the runoff flow to be harvested and collected or conserved in accordance to the needs, and use it to meet the requirement. This research investigates the role of rainwater management in order to overcome these problems. The literature review and field observations of experiences on rainwater management techniques applied on both communal scale and household level. The water-trap series are intended to manage the flowing of the rainfall water through the river or natural drainage, as water conservation approach.  The results show that firstly, rainwater must be managed in ways that small amount of rainwater flows out immediately to the sea. So, has chance to infiltrate into the soil as ground-water recharge. This is done by making some water-traps series, harvesting rainwater and storing it into the ponds at the household scale. The water then could be utilized for domestic and agriculture purposes. Secondly, learning from several experiences’ technology implementation as water conservation, it can be found the right way in managing rainwater of communal/household scale. These actions give the rainwater management have play role to solve problem related to hydro-environments engineering.

Light weight ferrocement is a composite material consisting of cement-sand mortar (matrix) along with light weight fine aggregate (In this research  blast furnace slag is employed as light weight fine aggregate)  as a replacement of sand in some quantity reinforced with layers of small diameter wire meshes and closely spaced small-diameter steel rods. The present work is concentrated on two major aspects, (i) Effect of blast furnace slag on ultimate strength and (ii) Behavior of light weight ferrocement element under flexural loading. The first part of the present study has been focused on the effect of blast furnace slag(BFS) on  ultimate strength with replacement of slag by 0%,10%, 20% & 30%  and second part of the work focusing the behavior of light weight ferrocement beam under monotonic & repeated loads with increased load. The results obtained from this work is expected to be useful in determining the first crack  strength and ultimate strength of light weight ferrocement beams subjected to similar types of forces and thus will help toward designing ferrocement elements to withstand monotonic and repeated flexural loading. The light weight ferrocement specimens having increased wire mesh (Volume fraction) could sustain greater number of repetitions, for all replacement of blast furnace slag.

An analysis of mathematical and biomechanical simulation of a system that represents movements of the human body at the time of developing activities of various operations was made. The most important part of the study, contemplated the use of Notch sensors placed in various parts of the human body to measure different positions of positions in various functions. The investigation consisted of three stages, the first being an analysis of movements of people in an industrial process of welding operation in small electronic circuit systems used in cellular telephony of a company located in the city of Mexicali. The second was a biomechanical simulation of a wooden structure with movable parts in the sagittal plane of the biomechanical analysis and the third a statistical analysis with the regression and correlation process to obtain a mathematical model that represented, various positions of the activities of the first step, and an effect of discomfort or serious health symptoms. With the results obtained, was made an evaluation to reduce labor accidents due to fatigue by at least 50%, being that Notch sensors, whose movement signals can be presented on a cell phone, having better effectiveness. The investigation was carried out from January 2018, until June 2019.

Among the several arc welding methods, the submerged arc welding is the preferred method for welding thick sections in the industry because of its several advantages which include high production rates, good weld quality, ease of automation and minimum operator skill requirement. This paper represents a study on the effect of B₂O₃ additions in fluxes on the microstructure and mechanical properties of the weld metal formed during Submerged Arc Welding of Mild Steel plates. Five fluxes with about 2.5, 5, 7.5, 10 and 12.5% B₂O₃ were used with a low carbon electrode. Welding process parameters were kept constant for all the conditions. The microstructure of weld metal for each flux consisted mainly of acicular ferrite, polygonal ferrite, grain boundary ferrites and equiaxed pearlite. It was noted that Vicker’s hardness value was a function of boron content and showed a mixed trend. Impact Energy and Tensile Strength were increased with the increase in boron content in welds this can be attributed to relation with the higher acicular ferrite percentage. However, an optimum level of toughness and tensile strength was available with 7.5% and 5% of B₂O₃ respectively.  A qualitative comparison has also been made with fresh flux through full metallography and mechanically.

This paper deals with some problems in the modernization of a type of machine tools with multi-coordinate drive systems. Machine tools are used for processing of workpieces with various geometrical shapes. The basic requirements to the drives of each coordinate axis and the spindle are presented. Using the analysis carried out, a practical approach to appropriate selection of the respective drives is applied. The methodology offered is illustrated with some examples for choice of drives with direct current and alternating current motors. Some experimental research of cases with different feed and spindle drives are described and discussed. Better capabilities of the modernized machines for processing more complex workpieces are achieved, at a relatively low price. This research and the obtained results can be used in the design and tuning of electric drives for the considered type of machines with numerical program control.

Laser forming of sheet metal is the bending process, induced by thermal stress, which is produced in the sheet by laser irradiation. Laser forming of complex shapes requires the study of the effect of various irradiation paths. In this paper the deformation of a circular plate, subjected to a circular irradiation path, is studied through a sequentially coupled thermo-mechanical elasto-plastic simulation by finite element method. The quality of laser bending in terms of waviness parameters, e.g., waviness average, R_a, RMS value, R_q, etc. are reported in detail, with respect to number of sections and number of passes of heating, as well as, shifting of the starting point for irradiation. It is observed that discrete section heating in symmetry with shifting in starting point of irradiation in subsequent passes reduces the undesired waviness, which is caused, otherwise, due to continuous circular heating. The results of finite element simulations presented in this chapter principally showed the possibility for a further increased knowledge of the mechanisms in 3D-laser forming.

This chapter examines two simple (albeit useful) methods used to evaluate the reliability of two-terminal multistate flow networks. These two methods involve two Karnaugh map versions, namely the Variable-Entered Karnaugh Map (VEKM) and the Multi-Valued Karnaugh Map (MVKM). These two versions are crucial in providing not only the visual insight necessary to write better future software but also adequate means of verifying such software. We assess these two versions of map methods versus the exhaustive search method, which guarantees conceptual clarity at the expense of lack of computational efficiency. Our target is the evaluation of the probability mass function (pmf) in a wide array of cases, in which we consider flow from a source node to a sink node in a capacitated network with a multistate capacity model for the links. Each network link has a varying capacity, which is assumed to exist in a mutually exclusive sense. The reliability of the system is wholly dependent on its ability to successfully transmit at least a certain required system flow from the source (transmitter) to the sink (receiver) station. The max-flow min-cut theorem is critical in obtaining all successful states. To demonstrate the proposed methods applicability, two demonstrative examples are given with ample details. The special case of a binary flow network is also considered in terms of pseudo-Boolean functions.

The paper presents the results of the study regarding the influence of shaking forces on olive tree harvesting systems. Shaking forces can be released through several methods. In order to use an automatic system for harvesting, we must calculate the necessary force of vibration to shake the olive tree. Important is the end result, namely the shaking force and the cadence of shaking speed. Mechanical and automatic harvesting methods collect more olives than traditional methods but may damage the olive trees. In order to prevent this damage, we need to calculate the necessary shaking force. An original research method is proposed to simulate shaking forces using a 3D olive tree model with Autodesk Inventor software. In the experiments, we use different shaking forces and various shaking speeds. We also use different diameters of the olive tree trunk. We analyze the results from this experiment to determine the optimal shaking force for harvesting olives without damaging the olive tree. All results were satisfactory on highest forces without breaking the olive tree.

In many countries, the design methods of flexible pavements are based on linear elastic behavior model for Unbound Granular Materials (UGM). In this context, the parameters required to characterize an UGM in structural analysis of these pavements are stiffness modulus and Poisson ratio (E and v). This paper presents a study of two UGM stiffness in which Finite element simulation of repeated load CBR (RL-CBR) test has allowed to derive the equation used in calculation of equivalent modulus, based on laboratory RL-CBR Outputs. Meanwhile, the staged RL-CBR test is used to evaluate material stiffness for different stress levels in order to highlight its influence on UGM stiffness and compare studied materials at the same time. As a result, this study shows that even if two materials are different according to the current road authority specifications, they can represent similar stiffness.