bluuebunny/crossref_metadata_2025_split huggingface dataset:
Avoiding Exit Burr in CNC End Milling by an Adapted Tool Path
Authors: Hassamontr Jaramporn , Blondaz Laurent , Dornfeld David A. 
Published: January 2022

Abstract
Most machining processes often require secondary operations such as edge finishing to improve the part’s form and function. The cost of the edge finishing operation can be significant, but is often neglected by part designers and process planners. In many cases, it is possible to avoid edge finishing process if the part’s edge quality is taken into consideration during part design and process planning stages. In milling, it has been known for some time that when the tool leaves the part while removing work material, burrs are likely to form. With this fundamental knowledge, a tool path generation algorithm that avoids exit burr formation was developed in this paper. The developed algorithm makes use of a traditional window framing tool path generation scheme. The validity of the algorithm is also investigated. Lastly, a comparison between the developed algorithm and traditional zigzag tool path planning algorithms is made.
Compliant Kinematic Couplings for Use in Manufacturing and Assembly
Authors: Culpepper Martin L. , Slocum Alexander H. , Shaikh F. Zafar 
Published: January 2022

Abstract
Repeatable positioning and rigid coupling are critical to manufacturing processes. Traditionally, pin joints and elastic averaging methods have been used to create reasonably repeatable and stiff joints. However, for repeatability below 200 μinches (5μm) these methods become expensive to manufacture. Less often used, are kinematic couplings which can attain sub-micron level repeatability, but have limited stiffness and don’t allow the mating of surfaces (as required in casting.)
In this paper, a new type of coupling, a compliant kinematic coupling, which combines the desirable characteristics of many methods is presented. The result is a coupling with the stiffness characteristics of elastically averaged couplings, good repeatability, and the ability to allow surfaces to mate. Repeatability tests in low cost versions of these couplings show radial repeatability of 200μinch (5μm) and angular repeatability of 57 μradians. This coupling method can be used in casting, assembly, fixturing, sheet metal forming, and other processes.
Capabilities of Parallel Link Machine Tools: Preliminary Investigations of the Variax Hexacenter™
Authors: Whittingham Ben D. , Gindy Nabil N. Z. , Chrisp Anthony G. , Powell Nigel P. , Geldart Mark , Al-Habaibeh Amin , Wykes Catherine M. , Ratchev Svetan M. , Webb Phil 
Published: January 2022

Abstract
This paper aims to highlight the work being done by the Rapid Response Aerospace Manufacture (RRAM) research group at the University of Nottingham in the area of capability investigations of parallel link machine tools. The paper focuses on the Giddings and Lewis Variax Hexacenter™, which has been in operation at the University of Nottingham’s Department of Manufacturing Engineering and Operations Management since September 1997.
In the first section of the paper the concept of parallel link machine tools is described, as well as the application of the Variax within the context of a responsive manufacturing cell. The second section details some of the standard machine capability tests applied to parallel link machines, and summarises the test results carried out to date on the Variax. The third section describes some aspects requiring investigation beyond these initial tests, and highlights the areas of knowledge which are generally underinvestigated for parallel link machines. An outline of the research being undertaken by the RRAM group to address these areas is then briefly described.
Elasto-Plastic Finite Element Analysis of Indentations in Free Abrasive Machining
Authors: Bhagavat Milind , Yang Fuqian , Kao Imin 
Published: January 2022

Abstract
Free abrasive machining (FAM) using a wiresaw is emerging as a state of the art technology for slicing large diameter semiconductor wafers. Material removal in a FAM environment is known to be by rolling and indenting of abrasives into the cut media. Therefore, indentation by abrasives in the slurry is the single most important mechanism in wiresawing process. This paper deals with the importance of abrasive shape in material removal during FAM. To achieve this objective, indentation by conical rigid abrasives of different included angles has been investigated using finite element method (FEM). Typical indentation fracture involving median, radial and transverse cracking has been explained to the maximum level of sophistication attainable using static stress analysis. Some industrially relevant results pertaining to FAM in general and wire-sawing in particular have been proposed.
Free Vibration Behavior of Unidirectional Composite Cylindrical Helical Springs With Circular Section
Authors: Yildirim Vebil , Sancaktar Erol 
Published: January 2022

Abstract
The free vibration problem of unidirectional composite cylindrical helical springs is modeled theoretically as a continuous system considering the rotary inertia, shear and axial deformation effects. The first order shear deformation theory is employed in the mathematical model. The twelve scalar ordinary differential equations governing the free vibration behavior of cylindrical helical springs made of an anisotropic material are solved simultaneously by the transfer matrix method. The overall transfer matrix of the helix is computed up to any desired accuracy by using the effective numerical algorithm available in the literature. The theoretical results are verified with the reported values, which were obtained theoretically and experimentally for straight beams. A parametric study is performed to investigate the effects of the number of active coils, the helix pitch angle and material types on the fundamental natural frequencies of helical springs with circular section and fixed-fixed ends.
The Development and Validation of Design-Oriented Metrics for Fretting Fatigue in Titanium Engine Components
Authors: Szolwinski M. P. , Harish G. , Farris T. N. 
Published: January 2022

Abstract
The area of contact between the blade root and disk in high-performance turbomachinery has been identified as a critical area for the nucleation of fatigue damage leading to premature and often catastrophic componential failures. The combination of high cycle aerodynamic and low cycle inertial loads lead to distributions of both normal and shear tractions at the blade/disk interface, leading to an aggressive tribological damage mechanism known as fretting. The interaction of small-scale, oscillatory relative displacements or slip at the contact surfaces and the sharp gradients of near-surface contact stresses induced by fretting contact is responsible for the nucleation of near-surface fatigue damage in these components. The paper will summarize efforts targeted at the development and validation of design-oriented tools for assessing quantitatively the threat of fretting fatigue to the integrity and subsequent performance of jet engine components.
A Multiparameter Model for the Prediction of Fatigue Crack Growth
Authors: Soboyejo A. B. O. , Foster M. A. , Katsube N. , Soboyejo W. O. 
Published: January 2022

Abstract
A new multiparameter model is proposed for the characterization of fatigue crack growth. The model assesses the combined effects of identifiable multiple variables that can contribute to fatigue crack growth. Mathematical expressions are presented for the determination of fatigue crack growth rates, da/dN, as functions of multiple variables, such as: stress intensity factor range, ΔK; stress ratio, R; closure stress intensity factor, Kmax, Kcl and the maximum stress intensity factor, frequency, Ω and temperature, T. A generalized emperical methodology is proposed for the estimation of fatigue crack growth rates as functions of these variables. The validity of the new methodology is then verified by making appropriate comparisons between predicted and measured fatigue crack growth data obtained from experiments on Ti-6Al-4V, in-conel 718 and HY80 steel. The multiparameter predictions are shown to be in close agreement with experimental data.
MEMS Testing Techniques for Long-Term Stability
Authors: Brown Stuart , Muhlstein Christopher , Abnet Cameron , Chui Clarence 
Published: January 2022

Abstract
Development of film processing technologies in the past decade has allowed the rapid application of MEMS to long-term, safety-critical and high performance applications. However, our understanding of the fundamental limitations of these small, structural components has evolved more slowly. The Micro-Structural Research Laboratory (μ-SRL) at Exponent has led the development of mechanical testing and qualification procedures for government and corporate MEMS. Current efforts to characterize mechanical properties of structural films include evaluating elastic properties and strength, fracture toughness, fatigue crack initiation and growth, and time-dependent phenomena such as creep.
Size Effects on Mechanical Properties of Polysilicon
Authors: Sharpe William N. 
Published: January 2022

Abstract
Polysilicon (chemically vapor deposited polycrystalline silicon) is the predominant structural material for MEMS products where the components have thicknesses of ten microns or less and minimum feature sizes of one micron or less. Although a corresponding bulk polysilicon manufactured in the same manner does not exist, it is nevertheless important to know whether the size of the manufactured component affects the Young’s modulus and strength of the material. This is still an open question, but there is research underway. A comprehensive survey is not intended here; Sharpe et al. (1997) contains a summary as of the end of 1996. The presentation will discuss recent developments in modulus and strength measurements with emphasis on electrostatic tensile tests.
Three-Dimensional Singular Stresses in Open Hole and Rigid Fastener Composites
Authors: Iarve E. V. 
Published: January 2022

Abstract
A three-dimensional solution valid in a composite laminate with a rigid fastener hole is obtained by combining a singular asymptotic solution with the B-spline displacement approximation. The hybrid approximation developed for the open hole problems was extended to rigid fastener hole problems. A near singular term of the asymptotic expansion present in the filled hole problem only was taken into account in order to obtain convergent solution with coarse spline approximation mesh. A bearing loaded [45/-45]s laminate was considered, and the multiplicative factors of the singular stress terms at the hole edge and ply interface were obtained.
Signal Pathways for Regulation of Plant Alternative Oxidase Genes’ Expression
Authors: Garmash E. V. 
Published: January 2022

Abstract
This review deals with important issues in regulation of terminal alternative oxidase (AOX) of plant mitochondria, which are currently investigated and discussed. AOX ensures electron transport along the alternative nonphosphorylating cyanide-resistant pathway in mitochondrial ETC and plays an important role in the maintenance of redox balance in the cell and defense against stress. Principal results concerning AOX signaling were obtained in the works dealing with expression of the АОХ1а gene of Arabidopsis thaliana (AtAOX1a). Reports about АОХ expression in different plant species were analyzed. Mechanisms of transcriptional and posttranscriptional control over expression of АОХ genes were described. The role of some cis-regulatory elements of AtАОХ1а promoter and related transcription factors was considered. It was shown that transduction of the signal causing expression of АОХ genes may follow anterograde and retrograde pathways. Information about mitochondrial retrograde regulation of AOX and ROS-dependent and ROS-independent signal pathways of induction of АОХ expression is given. A hypothetic sequence of signal events of light induction of АОХ1а expression in wheat leaf cell in the course of greening was worked out. Interactions between AOX signaling and hormonal signal pathways, as well as induction of АОХ by the signals of plastid origin, were described. In conclusion, it was highlighted that AOX is integrated into the common signal pathway of the cell and acts as a target and a regulator of signal events.
Generation of cDC-like cells from human induced pluripotent stem cells via Notch signaling
Authors: Makino Kenichi , Long Mark D , Kajihara Ryutaro , Matsueda Satoko , Oba Takaaki , Kanehira Kazunori , Liu Song , Ito Fumito 
Published: January 2022

BackgroundDendritic cells (DCs) play critical roles in regulating the innate and adaptive immune responses, and have long been a major focus of cancer immunotherapy. Accumulating evidence suggests that conventional type 1 DCs (cDC1s) excel in cross-presentation of exogenous antigens on MHC-I molecules and induction of antitumor CD8+T cell immunity; however, obtaining large numbers of cDC1s is difficult. The use of reprogramming and differentiation technology is advantageous for obtaining unlimited numbers of autologous cDC1s especially for therapeutic interventions where repeated vaccinations are required. However, generation of cDC1s from human induced pluripotent stem cells (iPSCs) remains elusive.MethodsHuman iPSCs established from peripheral blood T cells and monocytes were differentiated to myeloid cells under on-feeder or feeder-free culture conditions in vitro. Phenotype, genomic and transcriptomic signature, and function of human iPSC-derived DCs were analyzed. The role of Notch signaling for the generation of HLA-DR+cells from human iPSCs was interrogated by a loss- and gain-of-function approach.ResultsFlow cytometric analyses and single-cell profiling of HLA-DR+cells revealed that human iPSCs gave rise to CD141+XCR1+CLEC9A+cells (cDC1s), CLEC4AhiCLEC10A–CD1c+cells (cDC2As), CLEC4AloCLEC10A+CD1c+cells (cDC2Bs), CD163–CD5+CD1c+cells (CD5+cDC2s), and AXL+SIGLEC6+cells (AS-DCs) on OP9 feeder cells expressing the Notch ligand delta-like 1 (OP9-DL1) while the majority of iPSC-derived cells differentiated on OP9 cells were CD163+CD5–CD1c+cells (DC3s) and monocytes. Plasmacytoid DCs were not differentiated from iPSCs on either OP9 or OP9-DL1 cells. Inhibition of Notch signaling during co-culture of iPSC-derived CD34+hematopoietic progenitor cells with OP9-DL1 cells abrogated generation of cDC1s, cDC2As, cDC2Bs, CD5+cDC2s, and AS-DCs but increased frequency of DC3s. Notch-activated human iPSC-derived XCR1+CLEC9A+HLA-DR+CD11c+cells exhibited similar gene expression profile with peripheral blood cDC1s. Human iPSC-derived DCs have phagocytic, T-cell proliferative, and cytokine-producing functions.ConclusionsOur study demonstrates a critical role of Notch signaling in regulating developmental pathway of human cDCs. These findings provide insights into the future development of personalized treatment with unlimited numbers of autologous cDCs from human iPSCs.
Relational Gestalt approach to building a COVID-19 community of practice in a hospital setting
Authors: Denholm Justin T , Johnson Douglas , Denholm Gina C , Deligiannis Eva 
Published: January 2022

BackgroundThe COVID-19 pandemic has been highly disruptive in many work environments, particularly those related to direct provision of healthcare. Significant organisational change has been required at many levels, with attendant risks of both impaired service delivery and psychological impact on staff. Relational organisational Gestalt (ROG) is an approach that emphasises interpersonal connection about shared reality, which can be used in a variety of ways to support organisational change.MethodsWe established a community of practice in an acute hospital setting using ROG approaches during a COVID-19 pandemic wave. This group primarily consisted of senior medical staff redeployed to COVID-19 ward duties, who met daily for facilitated sessions centred around inpatient activities.ResultsEmerging group practices and outputs are described, including adjustments to group processes in response to situational need. A ROG approach was perceived as both effective in supporting rapid change in practice, and for providing psychological support for staff members.ConclusionsROG can be a useful and adaptive model for supporting staff and systems through times of change. Further exploration and evaluation of this approach in a variety of healthcare environments and applications will be valuable.
Combined balloon guide catheter, aspiration catheter, and stent retriever technique versus balloon guide catheter and stent retriever alone technique: a systematic review and meta-analysis
Authors: Teo Yao Neng , Sia Ching-Hui , Tan Benjamin Y Q , Mingxue Jing , Chan Bernard , Sharma Vijay Kumar , Makmur Andrew , Gopinathan Anil , Yang Cunli , Loh Stanley , Ng Sheldon , Ong Shao Jin , Teoh Hock-Luen , Rathakrishnan Rahul , Andersson Tommy , Arnberg Fabian , Gontu Vamsi Krishna , Lee Tsong-hai , Maus Volker , Meyer Lukas , Bhogal Pervinder , Spooner Oliver , Li Tony YW , Soh Rodney YH , Yeo Leonard LL 
Published: January 2022

BackgroundThe use of a combination of balloon guide catheter (BGC), aspiration catheter, and stent retriever in acute ischemic stroke thrombectomy has not been shown to be better than a stent retriever and BGC alone, but this may be due to a lack of power in these studies. We therefore performed a meta-analysis on this subject.MethodsA systematic literature search was performed on PubMed, Scopus, Embase/Ovid, and the Cochrane Library from inception to October 20, 2021. Our primary outcomes were the rate of successful final reperfusion (Treatment in Cerebral Ischemia (TICI) 2c–3) and first pass effect (FPE, defined as TICI 2c–3 in a single pass). Secondary outcomes were 3 month functional independence (modified Rankin Scale score of 0–2), mortality, procedural complications, embolic complications, and symptomatic intracranial hemorrhage (SICH). A meta-analysis was performed using RevMan 5,4, and heterogeneity was assessed using the I2test.ResultsOf 1629 studies identified, five articles with 2091 patients were included. For the primary outcomes, FPE (44.9% vs 45.4%, OR 1.04 (95% CI 0.90 to 1.22), I2=57%) or final successful reperfusion (64.5% vs 68.6%, OR 0.98 (95% CI 0.81% to 1.20%), I2=85%) was similar between the combination technique and stent retriever only groups. However, the combination technique had significantly less rescue treatment (18.8% vs 26.9%; OR 0.70 (95% CI 0.54 to 0.91), I2=0%). This did not translate into significant differences in secondary outcomes in functional outcomes, mortality, emboli, complications, or SICH.ConclusionThere was no significant difference in successful reperfusion and FPE between the combined techniques and the stent retriever and BGC alone groups. Neither was there any difference in functional outcomes, complications, or mortality.
Kinetic study on pyridinolysis of aryl benzenesulfonates: factors governing regioselectivity and reaction mechanism
Authors: Um Ik-Hwan , Jung Yoon Jae , Dust Julian M. 
Published: January 2022

A kinetic study is reported for reactions of 2,4-dinitrophenyl X-substituted-benzenesulfonates (1a–1f) and Y-substituted-phenyl benzenesulfonates (2a–2f) with Z-substituted-pyridines. The reactions proceed through S–O and C–O bond scissions competitively. The Yukawa–Tsuno plot for the reactions of 1a–1f with 4-oxypyridine (S–O bond fission) exhibits an excellent linearity. The Brønsted-type plot for the reactions of 2,4-dinitrophenyl benzenesulfonate (1d) with pyridines (S–O bond fission) is also linear with βnuc = 0.62. The Brønsted-type plot for the reactions of 2a–2f with 4-oxypyridines (S–O bond fission) is linear with βlg = –1.17. Thus, the reactions have been concluded to proceed through a concerted mechanism, in which leaving-group expulsion is significantly more advanced than bond formation between the electrophilic center and nucleophile at the transition state. The Hammett plot for the reactions of 1a–1f with 4-oxypyridine (C–O bond fission) exhibits scattered points with ρX = 0.98. The Brønsted-type plot for the reactions of 1d with Z-substituted-pyridines (C–O bond fission) results in an excellent linear correlation with βnuc = 0.38. Thus, the reactions (C–O bond fission) have been concluded to proceed through a stepwise mechanism with a Meisenheimer complex, in which expulsion of the leaving group occurs after the rate-determining step. Factors governing regioselectivity and reaction mechanism are discussed.
SYMMETRIC IMPACT OF EXCHANGE RATE VOLATILITY ON FOREIGN DIRECT INVESTMENT IN PAKISTAN: DO THE GLOBAL FINANCIAL CRISES AND POLITICAL REGIMES MATTER?
Authors: RAMZAN MUHAMMAD 
Published: January 2022

Understanding currency fluctuations carries a high level of risk. A currency can slide or spike as a response of an economic indicators revelation or an unexpected political event, both of which are unforeseeable. As foreign investors become more optimistic about the country’s future, a healthier economy usually requires a strong currency. Therefore, it is necessary to assess the exchange rate volatility risk in the context of direct investment in order to develop preventive policy routes that would encourage foreign investors into the country. To this purpose, the autoregressive distributive least square (ARDL) technique has been employed to investigate the symmetric effect of exchange rate volatility on foreign direct investment (FDI) during global financial crises and political regimes from January 2000 to December 2018. In order to eliminate arbitrariness, the study uses the most accredited estimate of volatility, GARCH (1 1), as part of the re-estimation process. Besides this, the interaction has been studied under various regimes to see how the political environment affects foreign market participants’ expectations for future gains. The findings suggest that exchange rate volatility is adversely related to FDI and is a source of decreased net foreign investment in Pakistan. It also illustrates that during times of crises and apolitical regimes, Pakistan’s average FDI falls dramatically. The findings are extended to the context of Pakistan that has seen significant rupee volatility for the past few years. Our study recommends that policymakers should pursue exchange rate measures that promote exchange rate stability, which might assist to minimize risk of exchange rate volatility and so attract higher FDI. It is also crucial to formulate more sustainable investment methods that allow for efficient capital allocation during times of economic uncertainty.