bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of predictive models for effective process parameter selection for single and overlapping laser clad bead geometry
Authors: Aggarwal Kush , Urbanic R.J. , Saqib Syed Mohammad 
Published: November 2017

Purpose
The purpose of this work is to explore predictive model approaches for selecting laser cladding process settings for a desired bead geometry/overlap strategy. Complementing the modelling challenges is the development of a framework and methodologies to minimize data collection while maximizing the goodness of fit for the predictive models. This is essential for developing a foundation for metallic additive manufacturing process planning solutions.

Design/methodology/approach
Using the coaxial powder flow laser cladding method, 420 steel cladding powder is deposited on low carbon structural steel plates. A design of experiments (DOE) approach is taken using the response surface methodology (RSM) to establish the experimental configuration. The five process parameters such as laser power, travel speed, etc. are varied to explore their impact on the bead geometry. A total of three replicate experiments are performed and the collected data are assessed using a variety of methods to determine the process trends and the best modelling approaches.

Findings
There exist unpredictable, non-linear relationships between the process parameters and the bead geometry. The best fit for a predictive model is achieved with the artificial neural network (ANN) approach. Using the RSM, the experimental set is reduced by an order of magnitude; however, a model with R2 = 0.96 is generated with ANN. The predictive model goodness of fit for a single bead is similar to that for the overlapping bead geometry using ANN.

Originality/value
Developing a bead shape to process parameters model is challenging due to the non-linear coupling between the process parameters and the bead geometry and the number of parameters to be considered. The experimental design and modelling approaches presented in this work illustrate how designed experiments can minimize the data collection and produce a robust predictive model. The output of this work will provide a solid foundation for process planning operations.
Effect of build orientation on the surface quality, microstructure and mechanical properties of selective laser melting 316L stainless steel
Authors: Alsalla Hamza Hassn , Smith Christopher , Hao Liang 
Published: November 2017

Purpose
The purpose of this paper is to investigate the density, surface quality, microstructure and mechanical properties of the components of the selective laser melting (SLM) parts made at different building orientations. SLM is an additive manufacturing technique for three-dimensional parts. The process parameters are known to affect the properties of the eventual part. In this study, process parameters were investigated in the building of 316L structures at a variety of building orientations and for which the fracture toughness was measured.

Design/methodology/approach
Hardness and tensile tests were carried out to evaluate the effect of consolidation on the mechanical performance of specimens. Optical and electron microscopy were used to characterise the microstructure of the SLM specimens and their effects on properties relating to fracture and the mechanics. It was found that the density of built samples is 96 per cent, and the hardness is similar in comparison to conventional material.

Findings
The highest fracture toughness value was found to be 176 MPa m^(1/2) in the oz. building direction, and the lowest value was 145 MPa m^(1/2) in the z building direction. This was due to pores and some cracks at the edge, which are slightly lower in comparison to a conventional product. The build direction does have an effect on the microstructure of parts, which subsequently has an effect upon their mechanical properties and surface quality. Dendritic grain structures were found in oz. samples due to the high temperature gradient, fast cooling rate and reduced porosity. The tensile properties of such parts were found to be better than those made from conventional material.

Originality/value
The relationship between the process parameters, microstructure, surface quality and toughness has not previously been reported.
Multi-scale finite element modeling of 3D printed structures subjected to mechanical loads
Authors: Calneryte Dalia , Barauskas Rimantas , Milasiene Daiva , Maskeliunas Rytis , Neciunas Audrius , Ostreika Armantas , Patasius Martynas , Krisciunas Andrius 
Published: November 2017

Purpose
The purpose of this paper is to investigate the influence of geometrical microstructure of items obtained by applying a three-dimensional (3D) printing technology on their mechanical strength.

Design/methodology/approach
Three-dimensional printed items (3DPI) are composite structures of complex internal constitution. The buildup of the finite element (FE) computational models of 3DPI is based on a multi-scale approach. At the micro-scale, the FE models of representative volume elements corresponding to different additive layer heights and different thicknesses of extruded fibers are investigated to obtain the equivalent non-linear nominal stress–strain curves. The obtained results are used for the creation of macro-scale FE models, which enable to simulate the overall structural response of 3D printed samples subjected to tensile and bending loads.

Findings
The validation of the models was performed by comparing the computed results against the experimental ones, where satisfactory agreement has been demonstrated within a marked range of thicknesses of additive layers. Certain inadequacies between computed against experimental results were observed in cases of thinnest and thickest additive layers. The principle explanation of the reasons of inadequacies takes into account the poorer quality of mutual adhesion in case of very thin extruded fibers and too-early solidification effect.

Originality/value
Flexural and tensile experiments are simulated by FE models that are created with consideration to microstructure of 3D printed samples.
Effects of micro particle reinforcement on mechanical properties of 3D printed parts
Authors: Çantı Ebubekir , Aydın Mustafa 
Published: November 2017

Purpose
The purpose of this paper is to characterize the effects of different micro particle reinforcement with same weight ratio in acrylonitrile-butadiene-styrene (ABS) feed-stocks for 3D printing process.

Design/methodology/approach
In this study, composite filaments were produced by using a co-rotational twin screw extruder and used as building material to print samples in a commercial fused deposition modeling (FDM) 3D printer. The reinforcement particles, ZrB2 and Al, have different properties, including density, surface area, purity and particle morphology, and were expected to improve mechanical properties of 3D printed samples. Differential calorimetry scanning and melt flow index studies were applied on the materials to observe the change in glass transition temperatures and melt flow behaviors, respectively. Also, to evaluate the mechanical properties, tensile and three-point bending test were carried out. Fractured surfaces were characterized via energy-dispersive X-ray spectroscopy for validation of the reinforcements in the ABS matrix. Moreover, scanning electron microscope micrograph examination was conducted on the fractured surfaces to characterize fracture modes.

Findings
For 3D printed samples, a strain increase of at least 82.5 per cent was achieved by using micro particle reinforcement with a weight ratio of 1.5 per cent.

Research limitations/implications
Higher filler ratios of the reinforcement particles cause loss on the printability of the feed-stocks.

Practical implications
Reinforced ABS stands out as a possible solution to overcome robustness problems in FDM printing.

Originality/value
Even though the effects of printing parameters on the mechanical properties of 3D printed parts have been vastly studied in the literature, studies conducted on improvement of the building materials are limited. This paper proposes to create novel feed-stock materials for achieving printed parts with superior properties using polymer composites.
Effects of titanium dioxide and tartrazine lake on Z-axis resolution and physical properties of resins printed by visible-light 3D printers
Authors: Chang Wei-Ting , Hsu Huang-Jan , Jiang Cho-Pei , Lee Shyh-Yuan , Lin Yuan-Min 
Published: November 2017

Purpose
The aim of this paper is to examine the effects of light controlling system that combined high refractive particles (n-TiO2 [titanium dioxide – TiO2]) and tartrazine lake dye (TL dye) on thickness, flexural strength, flexural modulus and surface details of the 3D-printed resin.

Design/methodology/approach
Influences of different concentrations of n-TiO2 and TL dye in light-cured resin formulations for 3D printing (3DP) application were evaluated, including curing thickness, flexural strength and surface details under scanning electron microscopy.

Findings
The polymerization thickness of samples containing both n-TiO2 and TL dye was lower compared to samples with TL dye solely. Samples containing more n-TiO2 and more TL dye exhibited lower flexural strength and modulus. Ramp models showed that for samples containing 1 per cent TL dye, when their n-TiO2 content increased from 1 to 5 per cent, surface laminate structures became sharper. However, when the TL dye content doubled to 2 per cent, the surface laminate structures were indefinite compared to 1 per cent TL dye-containing counterparts.

Originality value
In visible-light 3DP, light controlling system in cooperate dye with high refractive particles provides better energy distribution and scattering control. High refractive particles, dyes and light exposure time had influenced the surface resolution and mechanical properties of the 3DP products.
Curing parameters to improve the mechanical properties of stereolithographic printed specimens
Authors: Watters Matthew P. , Bernhardt Michelle L. 
Published: November 2017

Purpose
This paper presents findings from a study examining curing procedures to improve the compressive strength and hardness properties of specimens while maintaining surface quality. All specimens were created from a standard grey, acrylic-based photopolymer and fabricated using stereolithography technology. This paper aims to investigate the effects of printing layer thickness and print orientation on specimen compressive strength, as well as the effects of thermal and light curing methods. In addition, the post-print curing depth was investigated.

Design/methodology/approach
The effects of layer thickness and print orientation were investigated on 10 × 20 mm cylinders by determining the ultimate compressive strength once cured. The compressive strength of cylinders subjected to varying thermal and light settings was also investigated to determine the optimal curing settings. The effective depth of curing was investigated on a 25.4-mm cuboidal specimen, which received both thermal and light curing.

Findings
To achieve the highest compressive strength, specimens shall be printed with the minimal layer thickness of 25 µm. Increasing temperatures up to 60° C during curing provided a 0.75-MPa increase in compressive strength per degree Celsius. However, increasing temperatures above 60° C only provided a 0.15-MPa increase in compressive strength per degree Celsius. Furthermore, curing temperatures above 110° C resulted in degraded surface quality noted by defects at the layer laminations. Specimens required a minimum light curing exposure time of four hours to reach the maximum cure at which point any increase in exposure time provided no substantial increase in compressive strength.

Originality/value
This study provides recommendations for printing parameters and curing methods to achieve the optimum mechanical properties of cured stereolithography specimens.
Highly variable clinical feature and course of aggressive digital papillary adenocarcinoma
Authors: Yokota Kenji , Kono Michihiro , Shimizu Kazue , Sakakibara Akihiro , Akiyama Masashi 
Published: November 2017

AbstractAggressive digital papillary adenocarcinoma (ADPA) is a rare cutaneous tumor with sweat gland differentiation. Due to the high risk of local recurrence and delayed metastasis, the wide local resection of the primary lesion and long‐term follow up are recommended for ADPA. Here, we report two cases of ADPA. Case 1 had a blue‐gray nodule on the tip of the right middle finger. Case 2 had had a papule on the dorsal side of the left ring finger for 13 years. In both cases, papillary proliferations of the tumor cells showed multilobular adenomatous structures with back‐to‐back patterns characteristic of ADPA. We amputated the finger at the proximal interphalangeal joint and performed a wide resection of the primary tumor in Case 1 and 2, respectively. Sentinel lymph node biopsy in the axilla was performed, and no sentinel lymph node metastasis was found in either case. Among the previously reported ADPA cases, clinically, most lesions were skin‐colored or tan‐brown to gray. The blue‐gray color in Case 1 is thought to be extraordinary for ADPA. In Case 2, the patient had had the small lesion for more than 13 years and the tumor size had been stable during that long period. The present two cases suggest that ADPA shows a prominent variety of both clinical features and disease courses, and that we cannot exclude the possibility of ADPA even in cases of blue‐gray nodules or small, stable, non‐progressive papules.
Institutional Investment, Asset Illiquidity and Post‐Crash Housing Market Dynamics
Authors: Smith Patrick S. , Liu Crocker H. 
Published: November 2017

AbstractWe examine institutional investors’ entry into the equity side of the single‐family detached housing market using an asset illiquidity framework. We find that institutional investors purchased owner‐occupied houses after the real estate crisis for approximately 6.3–11.8% less than owner‐occupiers. The large discount was in addition to distressed sale and cash purchase discounts which, when combined, highlight the low liquidation value for owner‐occupied housing. The results suggest that asset illiquidity is an important cost of leverage in the owner‐occupied housing market.
Apparent transverse relaxation () on MRI as a method to differentiate treatment effect (pseudoprogression) versus progressive disease in chemoradiation for malignant glioma
Authors: Belliveau Jean‐Guy , Bauman Glenn S , Macdonald David , Macdonald Maria , Klassen L Martyn , Menon Ravi S 
Published: November 2017

AbstractIntroductionPseudoprogression (psPD) is a transient post‐treatment imaging change that is commonly seen when treating glioma with chemotherapy and radiation. The use of apparent transverse relaxation rate (), which is calculated from a contrast‐free multi‐echo gradient echo Magnetic Resonance Imaging (MRI) sequence, may allow for quantitative identification of patients with suspected psPD.MethodsWe acquired a multi‐echo gradient echo sequence using a 3T‐Siemens Prisma MRI. The signal decay through the echoes was fitted to provide the coefficient. We segmented the T1‐gadolinium enhancing the image to provide a contrast enhancing lesion (CEL) and the FLAIR hyperintensity to provide a non‐enhancing lesion (NEL). These regions of interest were applied to the multi‐echo gradient echo to acquire a mean within the CEL and NEL. We additionally acquired ADC data to attempt to corroborate our findings.ResultsWe found that patients who later exhibited PD exhibited a higher within the CEL as well as a higher ratio of CEL to NEL. Our data correctly distinguished pseudoprogression from treatment effect in 9/9 patients, while ADC corrected identified 7/9 patients using an absolute ADC of 1200 × 10−6 mm2/s.ConclusionsOur method seems promising for the accurate identification of psPD, and the technique is amenable to evaluation in larger, multi‐centre patient cohorts.
Narrowing filtered QRS duration on signal‐averaged electrocardiogram predicts outcomes in cardiac resynchronization therapy patients with nonischemic heart failure
Authors: Suzuki Atsushi , Shiga Tsuyoshi , Yagishita Daigo , Yagishita‐Tagawa Yoshimi , Arai Kotaro , Iwanami Yuji , Ejima Koichiro , Ashihara Kyomi , Shoda Morio , Hagiwara Nobuhisa 
Published: November 2017

BackgroundTo evaluate the impact of changes in the filtered QRS duration (fQRS) on signal‐averaged electrocardiograms (SAECGs) from pre‐ to postimplantation on the clinical outcomes in nonischemic heart failure (HF) patients under cardiac resynchronization therapy (CRT).MethodsWe studied 103 patients with nonischemic HF and sinus rhythm who underwent CRT implantation. SAECGs were obtained within 1 week before and 1 week after implantation and narrowing fQRS was defined as a decrease in fQRS from pre‐ to postimplantation. Echocardiography was performed before and 6 months after CRT implantation. The primary outcome was death from any cause. The secondary outcomes were hospitalization due to worsened HF and occurrence of ventricular tachyarrhythmias.ResultsOf the 103 CRT patients, 53 (51%) showed narrowing fQRS. Left ventricular end‐diastolic volume and end‐systolic volume were significantly reduced (both p < .001), and the left ventricular ejection fraction was significantly increased (p < .001) after CRT in patients with narrowing fQRS, but not in patients with nonnarrowing fQRS. During a median follow‐up period of 33 months, patients with narrowing fQRS exhibited better survival than patients with nonnarrowing fQRS (p = .007). A lower incidence of hospitalization due to worsened HF (p < .001) and a lower occurrence of ventricular tachyarrhythmias (p = .071) were obtained in patients with narrowing fQRS. After adjusting for confounding variables, narrowing fQRS was associated with a low risk of mortality (HR 0.27, p = .006).ConclusionOur results suggested that narrowing fQRS on SAECG after CRT implantation predicts LV reverse remodeling and long‐term outcomes in nonischemic HF patients.
Ophthalmic features of cone‐rod dystrophy caused by pathogenic variants in the ALMS1 gene
Authors: Nasser Fadi , Weisschuh Nicole , Maffei Pietro , Milan Gabriella , Heller Corina , Zrenner Eberhart , Kohl Susanne , Kuehlewein Laura 
Published: November 2017

AbstractPurposeWe aim to describe ophthalmic characteristics and systemic findings in a cohort of seven patients with cone‐rod retinal dystrophy (CORD) caused by pathogenic variants in the ALMS1 gene.MethodsSeven patients with Alström syndrome (ALMS) were included in the study. A comprehensive ophthalmological examination was performed, including best‐corrected visual acuity (BCVA), a semiautomated kinetic visual field exam, colour vision testing, full‐field electroretinography testing according to International Society for Clinical Electrophysiology of Vision (ISCEV) standards, spectral domain optical coherence tomography (SD‐OCT) and fundus autofluorescence (FAF) imaging, and slit lamp and dilated fundus examination. DNA samples were analysed using Sanger sequencing or exome sequencing.ResultsIn our cohort, the ocular phenotype presented with a wide variability in retinal function and disease severity. However, age of symptom onset (i.e. nystagmus and photophobia) was at 6–9 months in all patients. These symptoms mostly mislead to the diagnosis of congenital achromatopsia (ACHM), Leber congenital amaurosis (LCA), isolated CORD or Bardet–Biedl syndrome. The systemic manifestations in our cohort were highly variable.ConclusionIn summary, we can report that most of our ALMS patients primarily presented with nystagmus and severe photophobia since early childhood interestingly without night blindness in the absence of systemic symptoms. Only genetic testing analysing both nonsyndromic retinal disease (RD) genes and syndromic ciliopathy genes by comprehensive panel sequencing can result in the correct diagnosis, genetically and clinically, with important implication for the physical health of the individual.
Prediction of olanzapine exposure in individual patients using physiologically based pharmacokinetic modelling and simulation
Authors: Polasek Thomas M. , Tucker Geoffrey T. , Sorich Michael J. , Wiese Michael D. , Mohan Titus , Rostami‐Hodjegan Amin , Korprasertthaworn Porntipa , Perera Vidya , Rowland Andrew 
Published: November 2017

AimThe aim of the present study was to predict olanzapine (OLZ) exposure in individual patients using physiologically based pharmacokinetic modelling and simulation (PBPK M&S).MethodsA ‘bottom‐up’ PBPK model for OLZ was constructed in Simcyp® (V14.1) and validated against pharmacokinetic studies and data from therapeutic drug monitoring (TDM). The physiological, demographic and genetic attributes of the ‘healthy volunteer population’ file in Simcyp® were then individualized to create ‘virtual twins’ of 14 patients. The predicted systemic exposure of OLZ in virtual twins was compared with measured concentration in corresponding patients. Predicted exposures were used to calculate a hypothetical decrease in exposure variability after OLZ dose adjustment.ResultsThe pharmacokinetic parameters of OLZ from single‐dose studies were accurately predicted in healthy Caucasians [mean‐fold errors (MFEs) ranged from 0.68 to 1.14], healthy Chinese (MFEs 0.82 to 1.18) and geriatric Caucasians (MFEs 0.55 to 1.30). Cumulative frequency plots of trough OLZ concentration were comparable between the virtual population and patients in a TDM database. After creating virtual twins in Simcyp®, the R2 values for predicted vs. observed trough OLZ concentrations were 0.833 for the full cohort of 14 patients and 0.884 for the 7 patients who had additional cytochrome P450 2C8 genotyping. The variability in OLZ exposure following hypothetical dose adjustment guided by PBPK M&S was twofold lower compared with a fixed‐dose regimen – coefficient of variation values were 0.18 and 0.37, respectively.ConclusionsOlanzapine exposure in individual patients was predicted using PBPK M&S. Repurposing of available PBPK M&S platforms is an option for model‐informed precision dosing and requires further study to examine clinical potential.