bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multibody Dynamic Simulation of a Double ‘A’ Suspension Focusing on the Lower Control Arm Fatigue Life Analysis
Authors: Rodrigues L. P. , Silva R. C. , Oliveira A. B. S. 
Published: January 2018

A vehicle suspension subsystem consists of springs, shock absorbers and linkages, which attach to the wheels and chassis. The interaction between vehicle suspension and road generates dynamic forces in the suspension subsystem. In fact, vehicles travel at variable speed suffering a wide spectrum of vibrations and, usually, road profiles describe the roughness of the pavement surface, which represent their elevation as a function of a distance traveled or time. Consequently, suspension subsystem undergoes complex loading history that never reaches a level sufficient to cause failure in a single application. This means that components may fail due to fatigue.
At this context a Double A suspension, which has two sets of linkages called lower and upper control arms, could fail by fatigue according to MBS and FEA.
Thus, this work aims to present a MBS analysis of a Double A suspension submitted to a random road profile using a multibody commercial software. The fatigue life analysis focus in the lower control arm (LCA).
For this, forces components (longitudinal, vertical and lateral force) and torques, composed by eleven loading history acting on pre-defined points at the LCA, characterize the response of the component in such a situation. In fact, forces computed by multibody simulations improve the FEA by providing better assessment of how they vary throughout the random profile. For FEA, a methodology is proposed to simplify the loads acting at this element and perform the fatigue analysis by finite element method, in which transient analysis was performed.
This work represents a secondary stage of a broader study concerning the proposition of a constant amplitude proportional loading road profile based on the fatigue life results obtained from the complex loading history. Thus, it is expected to obtain in future works a simple signal to reproduce in numerical simulations, especially in fatigue analysis, and in experimental tests.
Numerical Investigation of the Drag of Rockets at Subsonic, Transonic and Supersonic Speeds
Authors: Steppert Michael , Epple Philipp 
Published: January 2018

To compute the trajectory of a rocket the knowledge of the external aerodynamics and the resulting forces is essential. The drag coefficient is an important parameter in the computation of rocket trajectory in case of vertical ascent. For compressible flows, at subsonic and supersonic velocities, the drag coefficient is a function of the Reynolds number and of the Mach number. Both dimensionless numbers depend on the temperature, however, not in the same way. For that reason, the Mach number dependency and the Reynolds number dependency are different. Since in the atmosphere pressure and temperature are functions of the height, the drag of rockets is also dependent on the height of the rocket in the atmosphere.
In this work, the dependence of the drag on the shape of the rocket is investigated at different heights and velocities, i.e. Reynolds and Mach numbers. For this purpose, the historical rocket from Johannes Winkler, the first liquid propulsion rocket in Europe, and a modern rocket geometry were chosen and compared. These rockets were investigated numerically with the commercial Navier–Stokes solver STAR-CCM+.
A detailed analysis of the drag coefficient, split into friction, pressure and wave drag was performed at these heights, Mach numbers and Reynolds numbers for the different aerodynamic shapes and rockets. In particular on the transonic and supersonic range the shock wave system leading to the wave drag was analysed in detail. Graphs of the corresponding friction, pressure, wave and total drag coefficients as a function of the Reynolds and as a function of the Mach numbers at different heights and a detailed analysis of these results are shown for the two rockets, the historical and a modern one.
Modeling and Experimental Characterization of Viscoelastic 3D Printed Spring/Damper Systems
Authors: Lai Heather L. , Kuang Cuiyu , Nelson Jared 
Published: January 2018

The development of flexible, viscoelastic materials for consumer 3D printers has provided the opportunity for a wide range of devices with damping behavior such as tuned vibration isolators to be innovatively developed and inexpensively manufactured. However, there is currently little information available about the dynamic behavior of these 3D printed materials necessary for modeling of dynamic behavior prior to print. In order to fully utilize these promising materials, a deeper understanding of the material properties, and the subsequent dynamic behavior is critical.
This study evaluates the use of three different types of models: transient response, frequency response and hysteretic response to predict the dynamic behavior of viscoelastic 3D printed materials based on static and dynamic material properties. Models of viscoelastic materials are presented and verified experimentally using two 3D printable materials and two traditional viscoelastic materials. The experimental response of each of the materials shows agreement with the modeled behavior, and underscores the need for improved characterization of the dynamic properties of viscoelastic 3D printable materials.
A Finite Element Model of a Surgical Knot
Authors: Qwam Alden Arz Y. , Geeslin Andrew G. , King Jeffrey C. , Gustafson Peter A. 
Published: January 2018

Background Surgical knots are one of several structures which can fail during surgical repair. However, there is no universal agreement on the superiority (best/safest) of one particular surgical knot technique. Tensile testing of repaired soft tissue has been used to assess the efficacy of surgical knot tying techniques, however, few computational models exist. The purpose of this study was to create a validated biomechanical model to evaluate the effect of knot configuration on the mechanical performance of surgical sutures.
Methods Two sutures were tested experimentally to find the mechanical properties and strength. Single throw knots were also tested for strength. Finite element models were constructed of each configuration and correlation was established.
Results The finite element results are quantitatively and qualitatively consistent with experimental findings. The FE model stress concentrations are also consistent with published strength reductions. Model and experimental results are presented using as-manufactured No. 2 FiberWire as well as its core and jacket constituents separately.
Clinical Relevance This paper describes a model which can evaluate the effect of knot topology on the mechanics of surgical suture. In the future, the model may be used to evaluate the mechanical differences between surgical techniques and suture materials. The findings may impact choices for suture and knot types selected for soft tissue repairs.
Analysis and Numerical Simulation of the Mechanical Performance of FDM Samples With Variable Infill Values
Authors: Cerda-Avila Steffany N. , Medellín-Castillo Hugo I. , de Lange Dirk F. 
Published: January 2018

The prediction of the mechanical properties of AM parts is very important in order to design and fabricate parts not only of any geometrical shape but also with variable or customized mechanical properties. A limited number of investigations have focused on the analysis and prediction of the mechanical properties of AM parts using theoretical and numerical approaches such as the Finite Element Method (FEM); nevertheless, their results have been not accurate yet. Thus, more research work is needed in order to develop reliable prediction models able to estimate the mechanical performance of AM parts before fabrication.
In this paper the analysis and numerical simulation of the mechanical performance of FDM samples with variable infill values is presented. The aim is to predict the mechanical performance of FDM components using numerical models. Thus, several standard tensile test specimens were fabricated in an FDM system using different infill values, a constant layer thickness, one shell perimeter, and PLA material. These samples were measured and modelled in a CAD system before performing the experimental tensile tests. Numerical models and simulations based on the FEM method were then developed and carried out in order to predict the structural performance of the specimens. Finally the experimental and numerical results were compared and conclusions drawn.
Applications of Fluid Structure Interaction Analysis Techniques for Flow Regulation
Authors: Gandikota Raju , Mallela Venkat , Quiroga Andres 
Published: January 2018

In fluid-structure interactions (FSI), one or more structures interact with incompressible or compressible fluids. These problems are non-linear multi-physics phenomena. Most FSI problems require a numerical solution rather than an analytical solution (Gene, 2012). This is particularly true for problems involving large deformations of elastomers and for problems related to plugging of flow. The classical two way coupling of fluid and structural solver does not work well and at times fail to reach a solution. Using a monolithic solver and non-conforming mesh techniques like Coupled Eulerian Lagrange (CEL) or Arbitrary Lagrange Eulerian (ALE) formulations we show solutions for such large deformation and plugging type FSI problems.
The technique has been applied to help develop an industrial flow regulator. The regulator uses a single piece elastomeric material that undergoes deformation due to pressure drop in the system. The deformation in turn restricts flow in the system and potentially developing flow related noise in the system. Rigorous FSI analyses techniques were used to design and develop the concepts minimizing prototype development time. The FSI analysis not only helped in designing the mechanical function of the regulator but also the helped evaluate the acoustic noise level in the system. The resulting design performance was validated by controlled performance tests. The design was shown to work reliably and meet performance requirements.
Solar Industrial Steam Production for Soap Manufacturing Factory: A Feasibility Study
Authors: Raiva Tafadzwa , Jen T. C. 
Published: January 2018

Industrial use of electricity in South Africa accounts for the largest consumption fraction, and the industry has the least renewable energy resource penetration rate. In the soaps manufacturing industry, steam is used to dry the semi-liquid soap mixture into solid noodles in the dryers. This process consumes 63047tons of steam per year, and the steam is produced by boiling water in the boiler heated using biomass and heavy fuel oil (HFO).
Feasibility of the system to produce industrial steam using solar energy was to be determined using two platforms: Cost feasibility and Area feasibility. Area feasibility refers to the determination of whether the space available for collector field installation can match the area required to meet steam load.
The optimized simulation showed that the required collector area was 17500m2, while the maximum available area on the roof was 12000m2, which implies that the space would not fit the required installation. As for the cost feasibility, the system has to have a payback period of less than 5 years for it be considered feasible and thus can be funded. The cost of installation was estimated to be USD $4 million, with an annual savings rate of $329000, hence a payback period of 12.1 years, which would be regarded as a long period of time for a savings project, therefore would be difficult for it to be approved by the factory administration as it is considered that a payback period of at most 5 years is favorable and the investment would be approved.
A Mechanical Engineering Activity-Based Freshman Course
Authors: Rios Oziel , Fadda Dani 
Published: January 2018

A freshman course is offered by the Mechanical Engineering (ME) Department at the University of Texas at Dallas (UTD). This course is a core course for the second semester of the freshman year. The course is divided into four segments where each segment addresses one area of mechanical engineering. The course is designed to facilitate the improvement of design activities from one semester to another based on student feedback, the needs of the mechanical engineering curriculum and contemporary issues important to the mechanical engineering profession.
The course is described in this paper along with the student’s response to specific questions related to the design projects. Specifically, feedback from a student survey administered at the end of the course is presented. This survey includes the student’s perception of their understanding of the topics studied, value of the activities for their future education, and their enjoyment of the activities. Comments received from the survey are also included and are used, along with instructor observations, to make improvements to the learning outcomes.
The course resources needed including lab space, computer software, tools, and teaching assistants are also discussed, as well as the course organization. A sample 16-week schedule is provided.
Lower Extremity Mechanism and Responses in Various Frontal Impact Configurations
Authors: Barbat Saeed , Li Xiaowei 
Published: January 2018

An analysis of the lower extremity responses in various frontal impact test configurations was performed. The THOR-LX anthropomorphic test device (ATD) representing a mid-size adult male was used. Four groups of frontal crash test data were analyzed. These groups included: Rigid Fixed Barrier (RFB), Moderate Overlap Offset Deformable Barrier (ODB), Small Overlap Rigid Barrier (SORB), and Oblique Impact (OI) crash tests.. This analysis indicated that the lower extremity responses could be high especially in the oblique impact and small overlap crash tests. This study focused on understanding the causes of the resulting high responses.
ATD lower extremity kinematics and interaction with intruded body structure and/or instrument panel varied in the different frontal impact configurations. Therefore, the dominant causes of lower extremity responses in terms of tibia forces and moments were not the same for all frontal crash modes. Maximum Tibia Index results associated with the four groups of frontal impact tests were used to develop a better understanding of ATD kinematics and response mechanisms of the lower extremities. The contact sequence of the lower leg to vehicle interior components was illustrated for OI.
This paper investigated the cause of lower extremity responses in these crash tests. Analysis indicated that the time at which maximum intrusion occurs did not necessarily coincide with the time of maximum lower extremity responses expressed by the Tibia Index.
Dot/Icm-Translocated Proteins Important for Biogenesis of the Coxiella burnetii-Containing Vacuole Identified by Screening of an Effector Mutant Sublibrary
Authors: Crabill Emerson , Schofield Whitman B. , Newton Hayley J. , Goodman Andrew L. , Roy Craig R. 
Published: January 2018

ABSTRACT

Coxiella burnetii
is an intracellular pathogen that replicates in a lysosome-derived vacuole. A determinant necessary for
C. burnetii
virulence is the Dot/Icm type IVB secretion system (T4SS). The Dot/Icm system delivers more than 100 proteins, called type IV effectors (T4Es), across the vacuolar membrane into the host cell cytosol. Several T4Es have been shown to be important for vacuolar biogenesis. Here, transposon (Tn) insertion sequencing technology (INSeq) was used to identify
C. burnetii
Nine Mile phase II mutants in an arrayed library, which facilitated the identification and clonal isolation of mutants deficient in 70 different T4E proteins. These effector mutants were screened in HeLa cells for deficiencies in
Coxiella
-containing vacuole (CCV) biogenesis. This screen identified and validated seven new T4Es that were important for vacuole biogenesis. Loss-of-function mutations in
cbu0414
(
coxH1
),
cbu0513
,
cbu0978
(
cem3
),
cbu1387
(
cem6
),
cbu1524
(
caeA
),
cbu1752
, or
cbu2028
resulted in a small-vacuole phenotype. These seven mutant strains produced small CCVs in all cells tested, which included macrophage-like cells. The
cbu2028
::Tn mutant, though unable to develop large CCVs, had intracellular replication rates similar to the rate of the parental strain of
C. burnetii
, whereas the other six effector mutants defective in CCV biogenesis displayed significant reductions in intracellular replication. Vacuoles created by the
cbu0513
::Tn mutant did not accumulate lipidated microtubule-associated protein 1A/1B light chain 3 (LC3-II), suggesting a failure in fusion of the CCV with autophagosomes. These seven T4E proteins add to the growing repertoire of
C. burnetii
factors that contribute to CCV biogenesis.
Transvaginal natural orifice transluminal endoscopic surgery (vNOTES) adnexectomy for benign pathology compared with laparoscopic excision (NOTABLE): a protocol for a randomised controlled trial
Authors: Baekelandt Jan Filip , De Mulder Peter A , Le Roy Ilse , Mathieu Chantal , Laenen Annouschka , Enzlin Paul , Weyers Steven , Mol Ben W J , Bosteels Jan J A 
Published: January 2018

IntroductionNatural orifice transluminal endoscopic surgery (NOTES) uses natural orifices to access the cavities of the human body to perform surgical interventions. NOTES limits the magnitude of surgical trauma and potentially reduces postoperative pain. Our group published a protocol on a randomised study comparing transvaginal NOTES (vNOTES) versus laparoscopy for hysterectomy (HALON). We simultaneously designed a similar randomised controlled trial (RCT) comparing vNOTES with laparoscopy for adnexectomy. To the best of our knowledge, this is the first RCT comparing vNOTES with laparoscopy for adnexal surgery.Methods and analysisThe methodology of the Notes Adnexectomy for Benign Indication versus Laparoscopic Excision (NOTABLE) study is similar to that of the HALON trial. Women aged 18–70 years with an indication for benign adnexal surgery will be eligible. We will use stratification according to adnexal size. Entrants will be randomised to the laparoscopic treatment (control) or vNOTES (intervention). Participants will be evaluated on days 0–7 and at 3 and 6 months. The primary outcome will be the proportion of women successfully treated by removing an adnexa by the allocated technique without conversion. We will collect the following data (secondary outcomes): proportion of women hospitalised on the day of surgery, postoperative pain scores measured two times per day from day 1 to 7, total dosage of pain killers used from day 1 to 7, hospital readmission during the first 6 weeks, dyspareunia and sexual well-being at baseline, 3 and 6 months using a validated questionnaire (Short Sexual Functioning Scale), health-related quality of life at baseline, 3 and 6 months after surgery using a validated questionnaire (EQ-5D-3L), duration of surgical intervention, infection or other surgical complications and direct costs up to 6 weeks following surgery. For the primary outcome measure, a one-sided 95% CI of the difference in the proportions of women with a successful removal of the uterus by the randomised technique will be estimated. Non-inferiority will be concluded when 15% lies above the upper limit of this 95% CI.Ethics and disseminationThe study was approved on 1 December 2015 by the EthicsCommitteeof the Imelda Hospital (registration no: 689), Bonheiden, Belgium. We aim to present the final results of the NOTABLE trial in peer-reviewed journals and at scientific meetings within 4 years after the start of the recruitment.Trial registration numberNCT02630329.
Managing cognitive impairment following stroke: protocol for a systematic review of non-randomised controlled studies of psychological interventions
Authors: Merriman Niamh A , Sexton Eithne , Donnelly Nora-Ann , McCabe Grainne , Walsh Mary E , Rohde Daniela , Gorman Ashleigh , Jeffares Isabelle , Pender Niall , Williams David , Horgan Frances , Doyle Frank , Wren Maev-Ann , Bennett Kathleen E , Hickey Anne 
Published: January 2018

IntroductionStroke is one of the primary causes of death and disability worldwide, leaving a considerable proportion of survivors with persistent cognitive and functional deficits. Despite the prevalence of poststroke cognitive impairment, there is no established treatment aimed at improving cognitive function following a stroke. Therefore, the aims of this systematic review are to identify psychological interventions intended to improve poststroke cognitive function and establish their efficacy.Methods and analysisA systematic review of non-randomised controlled studies that investigated the efficacy of psychological interventions aimed at improving cognitive function in stroke survivors will be conducted. Electronic searches will be performed in the PubMed, Embase and PsycINFO databases, the search dating from the beginning of the index to February 2017. Reference lists of all identified relevant articles will be reviewed to identify additional studies not previously identified by the electronic search. Potential grey literature will be reviewed using Google Scholar. Titles and abstracts will be assessed for eligibility by one reviewer, with a random sample of 50% independently double-screened by second reviewers. Any discrepancies will be resolved through discussion, with referral to a third reviewer where necessary. Risk of bias will be assessed with the Risk of Bias in Non-randomized Studies of Interventions tool. Meta-analyses will be performed if studies are sufficiently homogeneous. This review will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. The quality of the evidence regarding cognitive function will be assessed according to the Grading of Recommendations Assessment, Development and Evaluation.Ethics and disseminationThis systematic review will collect secondary data only and as such ethical approval is not required. Findings will be disseminated through presentations and peer-reviewed publication. This review will provide information on the effectiveness of psychological interventions for poststroke cognitive impairment, identifying which psychological interventions are effective for improving poststroke cognitive function.PROSPERO registration numberCRD42017069714.