bluuebunny/crossref_metadata_2025 huggingface dataset:
Personal Piety in Ancient Egypt
Authors: Luiselli Maria Michela
Published: April 2014

When talking about religion in ancient Egypt, one usually thinks about polytheism and the impressive state temples built throughout the country dating back to at least the age of the pyramids. What is less known, however, is that texts and material culture also show the existence of religious beliefs and practices of ordinary people who addressed the gods with prayers about daily troubles. In addition, gods were offered to at home, state temples had specific areas reserved for the presentation of prayers and offerings and people could buy votive offerings at the temple workshops to donate to the local gods. All this was rooted in the belief in the existence of gods who heard human prayers, responded to people's behaviour and intervened in daily life. To sum up personal piety in Egypt, it was the belief in a transcendent world and the interaction with it. The present article aims to illustrate the principle characteristics of this phenomenon and its development, along with related main research issues.
Impact of needle gauge on characterization of endobronchial ultrasound‐guided transbronchial needle aspiration (EBUS‐TBNA) histology samples
Authors: Jeyabalan Abiramy , Shelley‐Fraser Golda , Medford Andrew R.L.
Published: April 2014

Background and objective

Endobronchial ultrasound‐guided transbronchial needle aspiration (EBUS‐TBNA) is a minimally invasive mediastinal node sampling technique used for lung cancer staging and diagnosis of mediastinal lesions. The four published studies assessing sampling with 21‐G or 22‐G needles conflict. The study objective is to evaluate the diagnostic utility of 21‐G versus 22‐G EBUS‐TBNA needles, and the ability to subcharacterize both benign and malignant lesions using histopathological assessment only.

Methods

A retrospective analysis was performed from 303 patients referred for EBUS‐TBNA between January 2011 and July 2013. Sampling needle gauge was selected at the discretion of the operator. Samples were assessed by histopathologists blinded to the needle gauge without rapid on‐site evaluation for cytology. Contingency table analysis was performed to compare diagnostic utility and ability to subcharacterize malignant and benign lesions.

Results

No difference in diagnostic ability was seen for malignancy (96.6% v 95.3% accuracy, 21‐G vs 22‐G). Subgroup analysis of benign 21‐G tissue samples revealed superior characterization compared with 22‐G samples (63/76, 83%, vs 31/52, 60%, P < 0.01). Characterization of non‐small cell lung cancer (NSCLC) was also significantly better with samples obtained with 21‐G needles versus 22‐G needles (57/65, 88% vs 34/52, 65%, P < 0.01).

Conclusions

This large UK single‐centre study suggests 21‐G EBUS‐TBNA needles are superior to 22‐G in characterizing benign lesions (especially sarcoidosis) and NSCLC when using histopathological assessment. Making a positive benign diagnosis may avoid the need to perform mediastinoscopy. Obtaining sufficient histological material to subcharacterize NSCLC and particularly lung adenocarcinoma allows appropriate testing for genetic mutations facilitating targeted oncological therapy.
Development and psychometric evaluation of the Knowledge of Malnutrition – Geriatric (KoM‐G) questionnaire to measure malnutrition knowledge among nursing staff inAustrian nursing homes
Authors: Schönherr Silvia , Halfens Ruud J. G. , Lohrmann Christa
Published: April 2014

Introduction

Malnutrition is an internationally prevalent healthcare phenomenon in nursing home residents entailing serious consequences for those who are affected. Lack of knowledge among nursing staff is often discussed as a reason for deficits in nutritional practice. For this reason, a valid and reliable tool is necessary to assess knowledge of malnutrition (KoM) care. The objective of this study was to develop and psychometrically evaluate a questionnaire aimed at assessing the KoM care among nursing staff inAustrian nursing homes.

Methods

This study follows a psychometric methodological design. The dimensions and items of the questionnaire were derived from a literature review. The content validity was evaluated using aDelphi technique with eight international experts in the field of malnutrition. Item validity in terms of distribution of response alternatives, item difficulty and discrimination index, construct validity in terms of a comparison between predefined known groups and internal consistency using Kuder–Richardson 20 were analysed in a sample of 1152 registered nurses/nurse aides from 66 Austrian nursing homes.

Results

The Knowledge of Malnutrition – Geriatric (KoM‐G) questionnaire consists of 20 items with six answer options including ‘I don't know’ with established content validity. The quality of response alternatives ranged from 0.3 to 96.9%. The item difficulty of the total questionnaire was 59.3% and the discrimination index was 0.37, whereas one item had a discrimination index below 0.20 and was therefore deleted. Significant differences in percentage of correct answers between registered nurses and nurse aides, nursing staff with training in nutrition and without as well as between nursing staff with positive attitudes towards nutritional care and neutral or negative attitudes were found. TheKuder–Richardson 20 was 0.69.

Conclusion

The KoM‐G shows acceptable psychometric properties covering a wide range of items regarding malnutrition and can be applied in nursing home practice, education and research.
How spouses evaluate Nursing Home Placement of their demented partner: a study about the end of perseverance time
Authors: Kraijo Henk , de Leeuw Rob , Schrijvers Guus
Published: April 2014

Aim

This study was about the final decision by spouses to have their demented partner placed in a nursing home. The central question was whether the admission took place in the right time in their point of view.

Method

Fourteen partners of persons with dementia evaluated the nursing home placement. They were interviewed at home using a semi‐structured questionnaire. Grounded theory was used to explore the process of decision‐making. In addition to the interviews, quantitative data were used from a 2‐year follow‐up study.

Results

Results underline that the placement decision had to be made in phases over time. The first decision is about placement of the relative on a waiting list, and the second decision is about the actual placement in a nursing home once a place becomes available. This second and final decision often had to be taken under time pressure to avoid a place in the nursing home being left empty. If they had been given more time and space to reconsider their admission decision, most partners said they could have had continued providing homecare longer. During the investigation, the following classification in timeliness of the admission emerged: Placement was at the right time, too early, too late or out of control.

Conclusion

Spouses indicated they could have kept on giving care for a longer period of time if they had been given more time and space to make their final decision about the admission of their partner. It may be helpful for informal and formal carers to focus on perseverance time in considering placement or prolonged support at home. Placement at an appropriate time may lead to a higher degree of well‐being of informal carers before and especially after the admission.
Developing an Understanding of Race Talk
Authors: Goodman Simon
Published: April 2014

The aim of this paper is to give an outline of the discursive psychological literature focussing on prejudice and race talk and to show how recent findings suggest a development in this understanding. The paper begins with an outline of the discursive approach and the way in which it conceptualises race talk. Next, an overview of the ways in which people attempt to make prejudicial arguments so as to prevent them from appearing to be prejudiced, because of a norm against prejudice, is presented. It is then shown how challenges are being made to this norm against prejudice so that in some cases, prejudice can be viewed as acceptable, and in others, the taboo against prejudice is presented as being discriminatory on the grounds of preventing freedom of speech and proper debate.
Evaluation of serum thyroid hormones in dogs with systemic inflammatory response syndrome or sepsis
Authors: Pashmakova Medora B. , Bishop Micah A. , Steiner Jörg M. , Suchodolski Jan S. , Barr James W.
Published: April 2014

Objective

To determine whether dogs with systemic inflammatory response syndrome (SIRS) or sepsis have derangements in serum thyroid hormone concentrations and to evaluate whether such derangements relate to illness severity or outcome.

Design

Prospective observational study. Dogs hospitalized with SIRS or sepsis between May and December 2010 were included. Serum thyroid hormone concentrations were measured in all dogs. Data obtained on admission were used to calculate the Acute Patient Physiologic and Laboratory Evaluation (APPLE) scores.

Setting

University teaching hospital.

Animals

Twenty‐two consecutive client‐owned dogs hospitalized with SIRS or sepsis were enrolled; 18 dogs completed the study and 4 dogs were excluded for incomplete data. Forty‐nine healthy dogs owned by volunteers were used as controls.

Interventions

None.

Measurements and Main Results

Decreased total thyroxine (TT4) concentrations were documented in all septic and 7/9 dogs with SIRS. Free T4 concentrations were decreased, but were within the reference interval in 12/18 dogs with SIRS or sepsis compared to control dogs (P < 0.001). Dogs with increased APPLE(fast) scores were less likely to survive (P = 0.017).

Conclusions

Dogs with SIRS or sepsis have derangements in measured serum thyroid hormones. No relationships were identified between thyroid hormone concentrations and survival. The APPLE(fast) score was the only variable predictive of poor outcome.
Evaporation/Boiling Heat Transfer Performance in a Sintered Copper Mesh Structure
Authors: Diao Y. H. , Liu Y. , Zhao Y. H. , Wang S.
Published: April 2014

In this study, experimental investigations regarding the heat transfer performance of an evaporator with capillary wick are presented. The capillary wick structure is composed of sintered multilayer copper mesh. The multilayer copper mesh was sintered on the copper plate. With different combinations of mesh screens, the wick thickness of mesh 140 ranged from 0.6 to 1.0 mm, and those of meshes 60 and 140/60 were both 1.0 mm. The operating pressures used in this study were 0.86 × 105, 0.91 × 105, 0.96 × 105, 1.01 × 105, and 2.0 × 105 Pa. The experimental results indicate that the heat transfer performance was strongly dependent on the thickness of the sintered mesh structure and on the mesh size. The operating pressure also has a strong influence on the evaporation/boiling heat transfer performance of a mesh structure sintered using a single mesh size. However, it was also observed that the evaporation/boiling heat coefficient increased with an increase in the thickness of the capillary wick structure, which is less than 1.0 mm. The experimental results further illustrate that the composite sintered mesh structure was capable of properly enhancing the heat transfer performance, especially under high pressure. The maximum enhancement was 31.98%.
Radiometric and Metallurgical Analysis of Zone Formation in Elementary Laser Deposited Thin-Wall Structures
Authors: Hammell Joshua J. , Langerman Michael A. , Saunders Nathan P.
Published: April 2014

Laser Powder Deposition (LPD) is an additive manufacturing process used for solid freeform fabrication, surface modification, and part repair or remanufacture. This technology offers some significant advantages over traditional manufacturing processes, such as reduced post-process machining and reduced material waste. Most importantly, LPD offers increased flexibility in order to meet the demands of diverse markets. However, the connection between deposition parameters, thermal gradients, and final part quality is not sufficiently understood. The research discussed here shows how radiometric temperature measurements provide insight into the connection between process parameters and final part quality. These measurements can be used to augment the research and development process while maintaining process flexibility. Radiometric thermal data was collected during the deposition of ASTM/SAE 1045, 4130, and 4140 steel thin-wall samples. Several thermal zones were identified by radiometric analysis, and compared to post-process metallographic and dimensional inspection.
Production of Ultra-Fine-Grained Aluminum Plates by Constrained Groove Pressing Technique
Authors: Miyanaji Hadi , Panahi Ali Keshavarz , Hajavifard Ramin
Published: April 2014

One of the new methods of producing materials that have ultra-fine grains or grains of nanometer size is the method of severe plastic deformation (SPD). In this technique, by applying severe strains to the samples, the size of the grains is reduced to the nano scale, and as a result, the mechanical properties of the metal (including the yield strength and resistance to wear and abrasion) improve considerably. In this research, the effect of the constrained groove pressing process (as one of the SPD methods) on aluminum plates was studied. In this method, two dies (one with asymmetrical grooves, and the other, flat) were used for pressing the aluminum samples. With respect to the die’s geometry, at each pressing run, a shear strain equal to 0.58 is applied to some parts of the sample. By repeating the pressing operation, a large and significant amount of plastic strain is applied throughout the sample. In the present investigation, tensile and microhardness tests were employed to determine the effect of this process on the mechanical properties of the samples,. The results showed that, by increasing the number of pressing steps, hardness and strength of the samples increase, and the elongation ability diminishes. Of course, at higher numbers of pressing steps, a little decrease in strength was observed in the samples. Complete explanations regarding this decrease have been given in the text of the article.
A Framework for In-Line Milling Process Optimisation
Authors: Bosetti Paolo , Bort Carlos Maximiliano Giorgio
Published: April 2014

This work proposes a possible framework for implementing model-based optimization of process parameters in a milling operation. The latter is the first step in the development of an artificial machine tool operator, i.e. a supervising controller that looks at the process status and continuously estimate an optimal set of controls on the basis of a given process model. After a description of the software architecture, the discussion on the process model adopted for the definition of the target function, and the illustration of the optimization algorithm (the Nelder-Mead Method), the paper presents the results obtained from the application of the optimization system to two different case studies, showing how the same part-program can be run with significant improvements in productivity when the feed rate and spindle speed overrides are continuously varied during the machining according to profiles calculated by the proposed process optimization system.
Nanoparticle Reinforced Metal Composites Prepared by Electrocodeposition
Authors: Koludrovich Michael J. , Gan Yong X.
Published: April 2014

Improving the physical and mechanical properties such as hardness and strength of metal thin films can be achieved by incorporating nanoparticles into the pure metals, for example via electrocodeposition. However, the agglomeration of nanoparticles during electrocodeposition of nanocomposite thin films is an unresolved issue. This paper presents the preliminary results of electrocodeposition thin nanocomposite films under different processing conditions. The microstructure and distribution of Al2O3 nanoparticles in electrocodeposited Cu matrix nanocomposite thin films on a pure Al plate were examined. In addition, the effect of electrolyte concentration on the agglomeration of nanoparticles was studied. Different stirring times were used for electrodepositing the alumina/Cu nanocomposite and the pure Cu control film. Under the constant stirring condition, different deposition times including 1, 4, 8, 12, and 24 hours were taken to study the differences between the agglomeration states of the alumina nanoparticles with the time change. We also examined the effect of turning the electromagnetic stirrer ON and OFF at different time intervals from as short as every 20 minutes to as long as ON and OFF every 2 hours on the nanoparticle agglomeration in the film. Optical and electron microscopic studies were made to reveal the microstructure of the nanocomposite. It is found that there is no significant difference in microstructures for the specimens that made under either intermittent stirring or constant stirring for the same length of time.
Surge Characteristics and Range Extension With Steam Injection in a Centrifugal Compressor With Vaned Diffuser
Authors: Gao Chuang , Huang Weiguang , Yao Weijia , Duan Jicheng
Published: April 2014

This paper describes the experimental results of both steady and unsteady flow behavior and surge extension with steam injection in a centrifugal compressor with vaned diffuser and downstream collector. Specifically, the stage stability analysis and effects of steam injection on surge margin are reported based on experimental results in detail.

As the first step, a meanline analysis based on empirical correlations is utilized to find the possible stability dominated component. Then surge extension methods are put forward on the investigated compressor to enhance field operability.

To validate the meanline analysis, the static performance of both stage and components from the experiments were analyzed and the root cause of system surge was again given based on the classic stability theory.

The experimental results not only prove the validity of the former stability analysis but also extend the surge margin at least 9.0% with only 0.3% saturated steam of designed mass flow rate. During the experiments, it was also found that the surge margin improvement was not in proportion to the flow injected. In certain cases, the injected steam at large flow rate can even trigger system surge earlier.

To the authors’ known, this is the first report on surge extension with steam injection in open literature.
Estimation and Control of the Geometric Error in a Linear Interpolator With Parabola Blending
Authors: Li Hongbo
Published: April 2014

Given a sequence of G01 codes, a linear interpolator outputs a refined sequence of G01 codes obeying the inequality constraints imposed upon the velocity, acceleration, etc., of the machining tool, and the tracking error, geometric error, etc., between the two sequences. While the output G01 sequence is usually obtained from a continuous motion by sampling along the trajectory by a constant interpolation period, a simple strategy of generating the blending curve between two concatenated line segments under the velocity and axis-wise acceleration constraints of the machining tool, is to use parabolas — trajectories of constant-acceleration motions.

This paper considers the estimation and control of the geometric error in such a linear interpolator. Classical model of chord error by approximating parabolas with their contact circles leads to incorrect result on the geometric error, if the latter is taken as the superposition of (i) the error of approximation of the input G01 trajectory by parabolas, and (ii) the chord error caused by sampling along the blended C1-smooth trajectory. By computing the geometric error directly without accumulating the approximation error and the chord error, we realize correct geometric error control by establishing inequality constraints on the accelerations of the motion.

This work is supported partially by 2011CB302404, NSFC 10925105, 60821002/F02.
The Experimental Study on Forming Accuracy for Water Jet Incremental Sheet Metal Forming
Authors: He Kai , Li Jiuhua , Wei Shuguo , Du Ruxu
Published: April 2014

This paper aimed to present the methods to improve the forming accuracy for water jet incremental sheet metal forming. The study focuses on the process parameters and the forming accuracy based on the experiments. Firstly, some experiments was carried out to evaluate the deformation effect of sheet metal in water jet incremental sheet metal forming process with respect to some key parameters, such as water jet pressure and feed velocity. Then, the influence of layer on deformation was analyzed, and the theoretical model of forming accuracy and two methods to improve the forming accuracy were presented. Finally, the circular truncated cone parts formed with different methods and the profiles were measured with a coordinate measuring machine. Compared with the designed model geometry, the experimental results showed that an achievable forming accuracy could be obtained by the presented two methods.
Semi-Empirical Correlation to Predict the Sauter Mean Diameter of the Pressure-Swirl Atomizer
Authors: Xiao Wei , Huang Yong
Published: April 2014

In this study, experiments have been performed to investigate effects of pressure-swirl atomizer geometry on SMD. Different pressure-swirl atomizers were applied to study the effect of geometry on the SMD. Based on the experimental results, an empirical correlation was obtained to relate SMD with the Weber number characterized by film thickness. Meanwhile, a semi-empirical model which was improved from the surface wave breakup theory was established to predict the SMD of pressure-swirl atomizers. The model provides the droplet diameter as a function of atomizer geometry, operation condition and liquid properties. It is proved that the model is qualified for predicting SMD of pressure-swirl atomizers among wide range.
5-Axis In-Line Measurement System for Laser Materials Processing
Authors: Li Yangsheng , Xue Lijue , Wang Shaodong
Published: April 2014

The dimensional and positional information is very important for laser materials processing of components, especially for laser cladding-based additive manufacturing. Therefore, inspection of the component based on its original CAD model is essential to ensure the component meeting the geometrical requirements. In general, the processed component has to be dismounted from the laser fabrication system before it can be inspected, which is time-consuming and may introduce alignment error from datum.

In this paper, a 5-axis in-line measurement system is introduced, in which a non-contact laser measuring method along with CAD/CAM software is integrated to a laser materials processing system. An algorithm has been developed to automatically generate NC programs for measurement and comparison for outside features of components. Therefore, the inspection can be performed just after the component has been fabricated on the same system. Comparing to a 3-axis measuring system we reported before, the developed 5-axis inline measurement system provides much more flexibility, accessibility and accuracy for performing measurement on site. The developed in-line measuring capability can extend the functionality of conventional laser materials processing system and significantly shorten inspection time.
Effects of Initial Rolling Temperature on Rolling Deformation and Microstructure Evolution of 42CrMo Casting Ring Blank
Authors: Li Ju , Li Yongtang , Qi Huiping , Chen Huiqin
Published: April 2014

It is the basis for the new casting-rolling compound forming technology to investigate the rules of rolling deformation and microstructure evolution of casting ring blank. The initial rolling temperature of casting ring blank is one of the key factors influencing deformation and dynamic recrystallization behavior. In this paper, dynamic recrystallization models of as-cast 42CrMo steel were derived from thermo-simulation experimental results. Then, under DEFORM-3D software environment, deformation and dynamic recrystallization of 42CrMo casting ring blank were simulated at different initial rolling temperature by coupled thermo-mechanical finite element method. According to the simulation results, the effects of initial rolling temperature on strain fields distribution and dynamic recrystallization of 42CrMo casting ring blank were discussed. The results show that: (1) increased initial rolling temperature makes plastic deformation expand from ring’s outer and inner-layer to middle and distribute ever more evenly; (2) increased initial rolling temperature can lead to increased dynamic recrystallization fraction, but grain size of ring’s inner and outer-layer becomes smaller and smaller, while that of mid-layer coarser and coarser.
Development of Direct Printing/Curing Process for 3D Structural Electronics
Authors: Lu Yanfeng , Vatani Morteza , Kim Ho-Chan , Lee Rae-Chan , Choi Jae-Won
Published: April 2014

3D structural electronics is a new paradigm in fabricating electronics with high design complexity. Basically, manufacturing of 3D structural electronics consists of several processes: structure building, wire creation, and pick-and-place of electrical components. In this work, a 3D structure was built in a commercial AM machine, and conductive wires were created on the 3D structure with a predetermined design of an electronic circuit. Generally, 2D wire paths are projected to a 3D surface, and a tool path for the wire is generated in advance. And a direct printing device follows the tool path to draw the conductive wires on the surface, while a direct curing device simultaneously hardens the created wires using thermal/radiation energy. This direct printing/curing device was developed by combining a micro-dispensing device and a light focusing module installed in a motorized xyz stage. Several experiments were accomplished using photocrosslinkable materials filled with carbon nanotubes (CNTs). Finally, a 3D electronics prototype was fabricated to show the compelling evidence that the suggested manufacturing methods and materials would be promising in manufacturing 3D structural electronics.
G-Code Generation for a New Printing Process Based on 3D Plastic Polymer Droplet Generation
Authors: Schwaiger Johannes , Lueth Tim C. , Irlinger Franz
Published: April 2014

Fabrication of plastic parts is an important scope of application for various branches of industry. This does not only concern manufacturing of end products but also production of sample parts in small lot sizes. Currently, most plastic parts are injection-molded. Consequently, it is first necessary to produce appropiate moldings, for example by milling of metal. This is very time-consuming on one hand and uneconomical concerning costs for production in small lot sizes on the other hand. Furthermore, the variety of forms is restricted considerably which is a clear disadvantage concerning the production of prototypes or spare parts. The use of a free-forming droplet generator for producing plastic parts can provide remedy.

The patented principle of the printing process used in this approach is to produce droplets of liquified plastic in a preparation unit. Sequential discharge of these droplets builds a part in the installation space by solidifying of the droplets into balls. Since each 3D printing process needs its own data preprocessing, this article presents its fundamentals. STL data is used as input data and allows almost any kind of geometry. In general, a typical workflow for processing STL data is as follows: slicing volume data in order to gain contours that form 2D boarders, offsetting contours for a true to scale building process, filling of slices dependent on (offset) contours and generation of machine-code (g-code) that can be executed by the 3D printer in order to build an accurate and high-quality part.

The model used in this approach is based on the droplets produced by the machine. A more detailed description of all the process-specific invidual steps from slicing up to g-code generation is presented within the scope of this paper. The continual development of custom-made algorithms based on process-specific models and parameters has resulted in the generation of g-code that could be executed on a 3D plastic polymer printer based on droplet generation for the first time. The resulting sample parts are very appealing.

In conclusion, the results have shown that the whole production process can be a significant benefit especially for rapid prototyping of sample parts or spare parts.
Fatigue and Fracture Mechanics Analysis of Friction Stir Welded Joints of Aerospace Aluminum Alloys Al-2195
Authors: Wahab Muhammad A. , Raghuram Vinay
Published: April 2014

Friction-Stir-Welding (FSW) has been adopted as a major process for welding Aluminum aerospace structures. Aluminum (Al-2195) which is one of the new generations Aluminum alloys that has been used for the new super lightweight external tank for the space shuttle. NASA’s Michaud Assembly Facility (MAF) in New Orleans is continuously pursuing Friction-Stir-Welding (FSW) technologies in its efforts to advance fabrication of the external tanks of the space shuttles. The future launch vehicles which will have reusable mandates, for the structure to have good fatigue properties which prompts an investigation into the fatigue behavior of the friction stir welded aerospace structures. The butt joint specimens of Aluminum alloys (Al-2195 and Al-2219) are fatigue tested according to ASTM-E647. The effects of stress ratios, corrosion preventive compound (CPC), and periodic overloading on fatigue life is investigated. Scanning Electron Microscopy (SEM) is used to examine the failure surfaces and examine the different modes of crack propagation i.e. tensile, shear, and brittle modes. It is found that fatigue life increases with the increase in stress ratios; the fatigue life also increases from 30%–38% with the use of CPC; and the fatigue life could increase 8–12 times with periodic overloading; while the crack closure phenomenon predominates the fatigue fracture.

Numerical analysis has been used to model fatigue life prediction scheme for these structures, the interface element technique with critical bonding strength criterion for formation of new surface has been used to model crack propagation. The linear elastic fracture mechanics stress intensity factor is calculated using FEA and the fatigue life predictions made using this method; and are within 10%–20% of the experimental fatigue life obtained.
Measurements of Wall Formation Forces in an Acoustic Resonator
Authors: Barbely Natasha L. , Pirau Sorin I. , Komerath Narayanan M.
Published: April 2014

Acoustic or electromagnetic shaping in resonators can form thin walled structures from pulverized materials. The technology is applicable to a wide variety of materials, particle shapes, and sizes. While radiation force models adequately capture the transport of particles towards the nodal surfaces where walls form, the actual wall formation process involves complex particle-field and interparticle forces. A finite element computation is used along with pulsed laser particle image velocimetry for air movement, and particle tracking velocimetry for particle movement, to close the gap between predictions and measurements. Non-intrusive force measurement is attempted by deriving the acceleration field of particles, from velocity field data. Results are compared with particle acceleration computed from velocity calculations using the finite element code. The predicted acoustic velocity field from the standing wave pattern in the resonator, is compared with measurements. The difference between the computed particle velocity and the acoustic velocity is used to assess the relative roles of fluid dynamic drag and radiation forces on the acceleration of the particles. The measured particle acceleration does differ substantially and consistently from the computed values, showing the effect of the unmodeled near-field particle-field interaction forces.
RANS Modelling of Accelerating Boundary Layers
Authors: Oriji Ugochukwu R. , Tucker Paul G.
Published: April 2014

A numerical investigation of accelerated boundary layers (BL) has been performed using linear and non-linear eddy viscosity models (EVM). The acceleration parameters (KS) investigated range between 1.5×10−6 and 3.0×10−6. The one equation (k-l), Spalart Allmaras (SA) and the two-equation Menter SST and Chien models in their standard forms are found to be insensitive to acceleration. Nevertheless, proposed modifications for the SA, Chien and the k-l models significantly improved predictions. The major improvement was achieved by modifying the damping functions in these models and also an analogous source term, E, for the Chien model. Encouraging agreement with measurements is found using the Launder Sharma (LS), Cubic and Explicit Algebraic Stress Models (EASM) in their standard forms. The cubic model best predicted the turbulence quantities. Investigations confirm that it is practical for Reynolds Average Navier-Stokes (RANS) models to capture reversion from the turbulent to laminar state albeit for equilibrium sink type flows.
Quantitative Optimization of a Custom Flexible Manufacturing Platform for Assembly and Packaging of Heterogeneous Microsystems
Authors: Das Aditya
Published: April 2014

Manufacturing process for complex and heterogeneous systems in sub-millimeter scale requires several discontinuous and expensive steps. Batch manufacturing approach via legacy semiconductor processes often do not provide a viable solution for such type of product development due to either their inherent limitations of monolithic and in-plane design or commercial unsuitability in cases of low to medium production volumes. Therefore, alternative approaches, such as microassembly techniques, are warranted for this type of advanced manufacturing requirements. However, lack of standards for design and unavailability of off-the-shelf robotic assembly systems, augmented with scaling of physics in micro-domain, eventually renders the highly iterative approach toward product development cycle cost-inefficient and time-consuming. In ordered to deal with this compounded problem in micromanufacturing, it becomes imperative that a holistic approach be employed that develops not only the product but also the system that is used to construct the same. In our work, we demonstrate this concurrent engineering approach through a novel, analytical framework, called as “Design for Multiscale Manufacturability (DfM2)”. This framework, built into an interactive software application, enables the user to estimate common manufacturability metrics such as process yield, cycle time, overall cost and device performance, which improves the decision making in production and paves the pathway to commercialization by reducing the time and cost to market. Furthermore, we also demonstrate the implementation of the DfM2 application in evaluating the manufacturing of heterogeneous microsystems by a custom developed modular and reconfigurable manufacturing cell (MRMC). A real case-study has been discussed for the implementation of the DfM2.
Laser Diagnostics of Plasma in Synthesis of Graphene-Based Materials
Authors: Tuesta Alfredo D. , Bhuiyan Aizaz , Lucht Robert P. , Fisher Timothy S.
Published: April 2014

Scalable production of carbon nanostructures to exploit their extraordinary properties and potential technological applications requires an improved understanding of the chemical environment responsible for their synthesis. In this study the spatial distribution of the rotational temperature of hydrogen is investigated via coherent anti-Stokes Raman scattering spectroscopy in the plasma of a microwave plasma chemical vapor deposition reactor under parametrically controlled conditions. The reactor pressure is varied from 10 to 30 Torr and the plasma generator power from 300 to 700 W, simulating the conditions required for the synthesis of carbon nanotubes, graphene and graphitic nanopetals. Temperature measurements are conducted within the plasma sheath and up to 6 mm away from the puck surface in order to elucidate the spatial distribution of temperature within and around the plasma region. The results indicate a linear increase in rotational temperature of H2 with respect to the distance normal from the puck surface. Temperatures also increase with pressure. At 10 Torr the temperature range is approximately 850–1150 K while at 30 Torr it is approximately 1200–1650 K for a plasma generator power of 500 W. In addition, the temperature increases with plasma generator power and the introduction of other substances such as CH4 and N2. These findings may aid in understanding the function of the chemical composition and reactions in the plasma environment of these reactors which, to date, remains obscure. The spectroscopic techniques applied in this work may prove to be suitable in-situ monitoring methods for the scalable manufacturing of carbon nanomaterials.
3D Numerical Investigation of Thermally Assisted High Efficiency Ductile Machining of Brittle Materials
Authors: Ma J. , Pelate Nathan , Lei Shuting
Published: April 2014

This study investigates the effects of four different variables (initial workpiece temperature, side rake angle, edge radius/feed rate, and nose radius/depth of cut) on ductile regime machining of a bioceramic material known as nanohydroxyapatite (nano-HAP) using 3D numerical simulation. AdvantEdge FEM Version 5.9 is used to conduct the simulation of turning of the nano-HAP. Tecplot 360 is used to analyze the results of the simulations. Because the workpiece is thin, the entire workpiece is set to a uniform initial temperature to simulate laser preheating of the material. By varying initial workpiece temperature, rake angle (side rake angle), edge radius, and nose radius, the effects of these operating conditions on pressure distribution (critical feed) are investigated. It is found that critical feed increases as initial workpiece temperature increases, and as negativity of rake angle increases. For the edge radius, the critical feed appears to increase with this parameter. For the nose radius, critical feed seems to be independent of it.
A Preliminary Study on Machinability Assessment of Nanobainite Steel
Authors: Polishetty Ashwin , Littlefair Guy , Musselwhite Thomas , Sonavane Chinmay
Published: April 2014

The demand for high strength materials and improvements in heat treatment techniques has given rise to this new form of high strength steel known as nanobainite steel. The production of nanobainite steel involves slow isothermal holding of austenitic steel around 200°C for 10 days, in order to obtain a carbon enriched austenite and cooling to room temperature using austempering. The microstructure of nanobainite steel is dual phase consisting of alternate layers of bainitic ferrite and austenite. The experimental design consists of face milling under 12 combination of Depth of Cut (DoC)-1, 2 and 3mm; cutting speed-100 and 150m/min; constant feed- 0.15mm/rev and coolant on/off. The machinability of the material is assessed by means of analysis such as metallography and cutting force analysis. The results obtained are used to assess the most favorable condition to machine this new variety of steel. Future work involves study on phase transformation by quantifying the microstructural phase before and after milling using XRD.
Aeroelastic Response of an Aircraft Wing Modeled as a Thin-Walled Composite Beam
Authors: Durmaz Seher , Kaya Metin O.
Published: April 2014

This study reports static and dynamic aeroelastic analyses of an aircraft wing in an incompressible flow. A swept thin-walled composite beam with a biconvex cross-section is used as the structural model that incorporates a number of non-classical effects such as material anisotropy, transverse shear deformation and warping restraint. A symmetric lay-up configuration i.e. circumferentially asymmetric stiffness (CAS) is further adapted to this model to generate the coupled motion of flap-wise bending-torsion-transverse shear. For this beam model, the unsteady aerodynamic loads are expressed using Wagners function in the time-domain as well as using Theodorsen function in the frequency-domain. The divergence and the flutter speeds are evaluated for several ply angles and the aeroelastic response of an aircraft wing exposed to gust load is examined. The effects of transverse shear, fiber-orientation and sweep angle on the aeroelastic instabilities and the aeroelastic response of the beam are further discussed.
Investigations on Aerodynamic Loading Limits of Subsonic Compressor Tandem Cascades: Midspan Flow
Authors: Hertel Charlotte , Bode Christoph , Kožulović Dragan , Schneider Tim
Published: April 2014

An optimized subsonic compressor tandem cascade was investigated experimentally and numerically. Since the design aims at incompressible applications, a low inlet Mach number of 0.175 was used. The experiments were carried out at the low speed cascade wind tunnel at the Technische Universität Braunschweig. For the numerical simulations, the CFD-solver TRACE of DLR Cologne was used, together with a curvature corrected k-ω turbulence model and the γ-Reθ transition model. Besides the incidence variation, the aerodynamic loading has also been varied by contracting endwalls. Results are presented and discussed for different inlet angles and endwall contractions: pressure distribution, loss coefficient, turning, pressure rise, AVDR and Mach number. The comparison of experimental and numerical results is always adequate for a large range of incidence. In addition, a comparison is made to an existing high subsonic tandem cascade and conventional cascades. For the latter the Lieblein diffusion factor has been employed as a measure of aerodynamic loading to complete the Lieblein Chart of McGlumphy [1].
A Manufacturing Failure Mode Avoidance Framework for Aerospace Manufacturing
Authors: Goodland J. , Campean I. F. , Caunce A. , Victory J. L. , Jupp M. L.
Published: April 2014

Enhancement in productivity and cost effectiveness of high value manufacturing requires a process based management strategy. This paper introduces a Manufacturing Failure Mode Avoidance (MFMA) framework based on 4 high level process steps and underpinned by a sequence of engineering and process analysis tools to support a structured function-based decomposition of complex manufacturing processes and a continuous flow of information towards the development of robust control plans. The approach draws from experience in the automotive industry, where Failure Mode Avoidance (FMA) has been strategically adopted to achieve a step change in the effectiveness of business and engineering processes associated with the product creation processes. The paper presents a case study of the deployment of the MFMA framework to an aircraft manufacturing process followed by a broader discussion of the strength of the approach and its generic applicability to complex high value manufacturing engineering.
Suppression of Vortex Shedding Downstream of a Circular Cylinder Using Permeable Cylinders in Shallow Water
Authors: Özkan Göktürk Memduh , Akıllı Hüseyin
Published: April 2014

The characteristics of the flow around a 50mm circular cylinder surrounded by a permeable outer cylinder were investigated by Particle Image Velocimetry (PIV) and flow visualization techniques in order to control the unsteady flow structure downstream of the cylinder in shallow water. The effect of outer permeable cylinder with a porosity of β = 0.4 on the flow control was studied using five different diameters; D = 60, 70, 80, 90, 100mm. Depth-averaged free stream velocity was kept constant as U = 170mm/s corresponding to a Reynolds number of Re = 8500 and the water height was adjusted to hw = 25mm throughout the study. The results clearly showed that the outer permeable cylinder significantly affects the flow structure of the inner cylinder. It was found that by the existence of outer cylinder, the frequency of unsteady vortex shedding is reduced, vortex formation region is elongated and fluctuations are attenuated which are good indications of effective flow control. Owing to the results, optimum parameters were defined and suggested for the suppression of vortex-induced vibrations on bluff bodies.
Sustainable Interoperability of Negotiation of Manufacturing Robotic Machining Processes
Authors: Coutinho Carlos , Jardim-Goncalves Ricardo , Cretan Adina
Published: April 2014

The rise of new service-oriented technologies drives new ways to perform interoperability between manufacturing companies, even in areas not directly connected to the manufacturing enterprise core business. The aerospace segment is a highly competitive area, supported by numerous partners and applications which need to collaborate and be interoperable. Particularly, the subcontracted small and medium enterprises (SMEs) need to be flexible towards the changes that are imposed by the major contractors, doing so at the lowest cost. This paper proposes a framework based on Model Driven Interoperability (MDI) and service orientation principles, which advocates negotiations as a pillar mechanism towards the achievement of sustainable interoperability in manufacturing organisations acting in the same industrial market, using a service-oriented platform. The framework encompasses a set of tools that implement the business modelling and negotiation rules, including a reference ontology, and supported by a set of cloud-based services deployed in a cloud infrastructure. The underlying complexity is to model the dynamic environment where multi-attribute and multi-participant negotiations are racing over a set of heterogeneous resources. The evolution of the negotiations is performed through the use of the metaphor Interaction Abstract Machines (IAMs). This framework is then illustrated by the case study of the European Space Agency – Concurrent Design Facility (ESA-CDF) department, which performs feasibility studies for space missions.
Creation and Characterization of Doped Hydroxyapatite With Strontium Carbonate Thin Film Coating on Titanium Substrates Using Pulse Laser Deposition for Biological Applications
Authors: Waters Cindy , Ajinola Stephen , Kumar Dhannajay , Darkwa Kwadwo-mensah , Sedighi Ahmadreza
Published: April 2014

The main purpose of this paper is to investigate mechanical properties of thin films of strontium carbonate (Sr2CO3) doped with hydroxyapatite (HA) on titanium substrates using nanoindentation techniques. The variation in the weight percentages of strontium carbonate of 0 wt %, 2.5 wt % and 100 wt % of Sr2CO3 in hydroxyapatite on a titanium substrate were used to investigate the effect of strontium carbonate on the surface modification for biological application. The hope is to use these results to improve the surface hardness of dentures and boost cavity prevention, and to improve menopause bone loss and help in its remodeling. The hardness and elastic moduli of different weight percents of variation in the compositions of strontium carbonate in Sr2CO3 - HA thin film layers deposited at 600 °C on titanium substrates using Pulse Laser Deposition (PLD) at high vacuum of 10−6 Torr were measured. The effect of varying Sr2CO3 in HA on the crystallinity, on the microstructure and on film thickness was determined using X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and stylus profilometer respectively. The Sr2CO3 - HA with the composition of 2.5 wt. % of Sr2CO3 has average film thicknesses of each composition of the film were also recorded and a hardness performance of 3.89 GPa, good peak broadening was also observed in the 2.5 wt % composition Sr2CO3 using XRD. The variations in the composition of strontium Carbonate in Hydroxyapatite in term of hardness and elastic moduli were reported.