scholarly journals Stress Transfer Mechanism of Flange in Split Hopkinson Tension Bar

2020 ◽  
Vol 10 (21) ◽  
pp. 7601
Author(s):  
Hyunho Shin ◽  
Sanghoon Kim ◽  
Jong-Bong Kim
Keyword(s):  
Stress Transfer ◽  
Transfer Mechanism ◽  
Explicit Finite Element ◽  
Impact Theory ◽  
Quantitative Basis ◽  
Split Hopkinson ◽  
One Step ◽  
The One ◽  
The Impact ◽  
Split Hopkinson Tension Bar

To reveal the stress transfer mechanism of the flange in a split Hopkinson tension bar, explicit finite element analyses of the impact of the hollow striker on the flange were performed across a range of flange lengths. The tensile stress profiles monitored at the strain gauge position of the incident bar are interpreted on a qualitative basis using three types of stress waves: bar (B) waves, flange (F) waves, and a series of reverberation (Rn) waves. When the flange length (Lf) is long (i.e., Lf > Ls, where Ls is the striker length), the B wave and first reverberation wave (R1) are fully separated in the time axis. When the flange length is intermediate (~Db < Lf < Ls, where Db is the bar diameter), the B and F waves are partially superposed; the F wave is delayed, then followed by a series of Rn waves after the superposition period. When the flange length is short (Lf < ~Db), the B and F waves are practically fully superposed and form a pseudo-one-step pulse, indicating the necessity of a short flange length to achieve a neat tensile pulse. The magnitudes and periods of the monitored pulses are consistent with the analysis results using the one-dimensional impact theory, including a recently formulated equation for impact-induced stress when the areas of the striker and bar are different, equations for the reflection/transmission ratios of a stress wave, and an equation for pulse duration time. This observation verifies the flange length-dependent stress transfer mechanism on a quantitative basis.

scholarly journals Performance Analysis and Optimization of CRNs Based on Fixed Feedback Probability Mechanism with Two Classes of Secondary Users

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Yuan Zhao ◽  
Hongyi Li ◽  
Jiemin Liu
Keyword(s):  
Performance Indicators ◽  
Three Dimensional ◽  
Secondary Users ◽  
Lower Priority ◽  
Fixed Parameter ◽  
One Step ◽  
The One ◽  
The Impact ◽  
Retransmission Control ◽  
Transfer Probability

In this paper, we conduct a research based on the classified secondary users (SUs). SUs are divided into two categories: higher-priority SU1 and lower-priority SU2, and two types of users generate two types of packets, respectively. Due to the lowest spectrum usage rights of SU2 packets, the SU2 packets’ transmission is easily interrupted by other packets with higher rights. With the purpose of controlling the SU2 packets’ retransmission behavior, we introduce two system parameters, namely, feedback threshold T and feedback probability q. When the amount of SU2 packets in the buffer reaches the feedback threshold T, the interrupted SU2 packets either enter the buffer with probability q for retransmission or leave the channel by probability 1−q, where q is a fixed parameter. We construct a three-dimensional Markov model based on the presented retransmission control mechanism and derive some important performance indicators of SU2 packets based on the one-step transfer probability matrix and steady-state distribution. Then, we analyze the impact of some key parameters on the performance indicators through numerical experiments. Finally, we establish a cost function and use particle swarm optimization algorithm to optimize the feedback threshold and feedback probability.

Sentinel Nodal Micrometastases Detected by the One- Step Nucleic Acid Amplification Whole Node Assay and the Impact on Adjuvant Treatment and Outcomes in Early Breast Cancers: The First Report from Thailand

2021 ◽  
Vol 104 (5) ◽  
pp. 764-771
Keyword(s):  
Adjuvant Treatment ◽  
Survival Benefit ◽  
Systemic Chemotherapy ◽  
Lymph Node Biopsy ◽  
Nucleic Acid Amplification ◽  
Node Biopsy ◽  
One Step ◽  
The One ◽  
The Impact ◽  
Osna Assay

Background: The advent of sentinel lymph node biopsy (SLNB) and improvements in histopathological and molecular analysis have increased the detection rate of nodal micrometastases. As compare with conventional method, the one-step nucleic acid amplification (OSNA) assay might detect higher cases of SLN micrometastases. Objective: The present study aimed to assess the impact of OSNA assay on micrometastases detection rate and potential benefit in terms of adjuvant treatment and survival outcome in early breast cancer. Materials and Methods: A retrospective review of patients with sentinel node (SLN) micrometastasis detected by the OSNA assay between 2015 and 2019 was carried out. Clinicopathological, adjuvant treatment, and follow-up data were collected. Ten-year survival benefit with adjuvant chemotherapy was calculated using PREDICT online, version 1.2 (https://breast.predict.nhs.uk/). Results: Between November 2015 and December 2019, 78 out of 721 patients (10.8%) were positive for micrometastasis based on OSNA detection. Three-fourth of cases received adjuvant systemic chemotherapy and 57% were given taxane-based regimen. Using the PREDICT online tool, an estimated 10-year survival in patients who received adjuvant systemic chemotherapy and who did not, were 75% and 66%, respectively (p=0.018). A 10-year survival benefit from chemotherapy among patients who received systemic chemotherapy was 8% compared with 4% with no-adjuvant-therapy cohort. Conclusion: The OSNA assay allows for a more precise detection of SLN micrometastasis compared to conventional pathology and could guide therapeutic decision making. In patients with micrometastasis who received adjuvant systemic chemotherapy, the estimated overall 10-year survival was improved. Keywords: Axillary staging, Breast cancer, Micrometastases, OSNA, Sentinel lymph node biopsy

scholarly journals Electrochemical Oxidation of Ti15Mo Alloy—The Impact of Anodization Parameters on Surface Morphology of Nanostructured Oxide Layers

Nanomaterials ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 68
Author(s):  
Magdalena Jarosz ◽  
Leszek Zaraska ◽  
Marcin Kozieł ◽  
Wojciech Simka ◽  
Grzegorz D. Sulka
Keyword(s):  
Surface Morphology ◽  
Pure Titanium ◽  
Elemental Content ◽  
Potential Range ◽  
Oxide Layers ◽  
X Ray ◽  
Nanostructured Oxide ◽  
One Step ◽  
The One ◽  
The Impact

It is well-known that the structure and composition of the material plays an important role in the processes occurring at the surface. In this paper, a surface morphology of nanostructured oxide layers electrochemically grown on Ti15Mo, tuned by applying different anodization parameters, was investigated in detail. The one-step anodization of Ti15Mo alloy was performed at room temperature in an ethylene glycol-based electrolyte containing 0.11 M NH4F and 1.11 M H2O. Different anodization times (ranging from 5 to 60 min) and applied potentials (40–100 V) were tested, and the surface morphology, elemental content, and crystalline structure were monitored by scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), and X-ray diffractometry (XRD), respectively. The results showed that contrary to the multistep anodization of titanium foil, the surface morphology of anodic oxide obtained via the one-step process contains the nanoporous outer layer covering the nanotubular structure. What is more, the pore diameter (Dp) and interpore distance (Dint) of such layers exhibit different trends than those observed for anodization of pure titanium. In particular, at a certain potential range, a decrease in both Dp and Dint with increasing potential was observed. However, independently on the used anodization conditions, the elemental content of oxide layers remained similar, showing the amount of molybdenum at c.a. 15 wt.%. Finally, the amorphous nature of as-anodized layers was confirmed, and their optical band-gap was determined from the diffuse reflectance UV–Vis spectra. It was found that Eg is tunable to some extent by changing the anodizing potential. However, further thermal treatment in air at 400 °C resulted in the anatase phase formation that was accompanied by a significant Eg reduction. Therefore, we believe that the presented results will greatly contribute to the understanding of anodic formation of nanostructured functional oxide layers with tunable properties that can be applied in various fields.

scholarly journals Synthesis of Poly(Trimethylene Carbonate) from Amine Group Initiation: Role of Urethane Bonds in the Crystallinity

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 280
Author(s):  
Thomas Brossier ◽  
Gael Volpi ◽  
Vincent Lapinte ◽  
Sebastien Blanquer
Keyword(s):  
Thermal Studies ◽  
Trimethylene Carbonate ◽  
X Ray Diffraction ◽  
One Pot ◽  
Free Process ◽  
One Step ◽  
The One ◽  
Natural Amino Acids ◽  
The Impact

Semi-crystalline poly(trimethylene carbonate) (PTMC) can be efficiently prepared by ring-opening polymerization (ROP) initiated by amine using various catalysts. More promising results were reached with the one-step process of stannous octanoate unlike the two-step one-pot reaction using TBD and MSA catalysts. The ROP-amine of TMC consists in a simple isocyanate free process to produce polycarbonate-urethanes, compatible with the large availability of amines ranging from mono- to multifunctional until natural amino acids. ROP-amine of TMC leads to urethane bonds monitored by FTIR spectroscopy. The relationship between the nature of amines and the crystallinity of PTMC was discussed through X-ray diffraction and thermal studies by DSC and TGA. The impact of the crystallinity was also demonstrated on the mechanical properties of semi-crystalline PTMC in comparison to amorphous PTMC, synthesized by ROP initiated by alcohol. The semi-crystalline PTMC synthesized by ROP-amine opens many perspectives.

scholarly journals Design guidelines for the striker and transfer flange of a split Hopkinson tension bar and the origin of spurious waves

2019 ◽  
Vol 234 (1) ◽  
pp. 137-151
Author(s):  
Hyunho Shin ◽  
Jae-Ha Lee ◽  
Jong-Bong Kim ◽  
Sung-Ik Sohn
Keyword(s):  
Design Guidelines ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Element Analysis ◽  
Cross Sectional ◽  
Explicit Finite Element ◽  
Stress Pulse ◽  
Explicit Finite Element Analysis ◽  
Split Hopkinson ◽  
Split Hopkinson Tension Bar

Characteristics of the stress pulse generated by impact of a hollow striker on the flange of a split Hopkinson tension bar are investigated via an explicit finite element analysis. Design guidelines are extracted for the hollow striker and flange from the viewpoint of eliminating spurious waves located between the incident and reflected pulses. According to design guidelines, it is desirable to have a striker cross-sectional area the same as that of the flange. It is also desirable to make the cross-sectional area of the striker (flange) the same as that of the bar. As for the flange length, it is recommended to be comparable to the diameter of the bar. The magnitude and duration of the primary stress pulse are consistent with the results of a one-dimensional analysis even when spurious waves are present; meanwhile, overly long spurious waves should be avoided to eliminate their superposition with the reflected pulse. Spurious waves appear when general impedance of the striker is higher than the bar. The origin of spurious waves is a series of step-wise residual pulses generated by multiple cycles of striker impact that make the striker keep compressing the flange after the first cycle of impact. Step-wise residual pulses appear in two forms (continuous waves and discrete waves) in spurious waves due to the secondary impacts during the entrance process of step-wise residual pulses to the flange. The consequences of spurious waves in the use of split Hopkinson tension bars are discussed.

An exploration of the impact of artificial intelligence (AI) and automation for communication professionals

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Eduardo Alejandro López Jiménez ◽  
Tania Ouariachi
Keyword(s):  
Artificial Intelligence ◽  
Human Life ◽  
Content Type ◽  
Methodological Triangulation ◽  
Analytical Thinking ◽  
One Step ◽  
Automated Tools ◽  
The One ◽  
The Impact ◽  
Near Future

Purpose Artificial intelligence (AI) and automation are currently changing human life with a great implication in the communication field. This research focusses on understanding the current and growing impact of AI and automation in the role of communication professionals to identify what skills and training are needed to face its impacts leading to a recommendation. Design/methodology/approach The research involves methodological triangulation, analysing and comparing data gathered from consulting with experts using the Delphi method, focus group with communication students, and literature review. Findings Findings show that the likely impacts are on the one hand the enhancing of efficiency and productivity, as well as freeing communication professionals to focus on the creative side, strategy and analytical thinking, on the other hand, repetitive and low-level jobs could be lost, being higher position jobs or those involving creativity and decision making harder to automate. Two types of training are needed: to gather experience with the current AI and automated tools, and to focus on developing human qualities that AI cannot replicate. Originality/value The outcomes of this research are valuable to help current and future communication practitioners, as well as organisations, to be one step ahead and survive the age AI and automation, being aware of its current and near-future impacts. The paper offers a list of recommended soft and technical skills, as well as training needed, categorizing them in low, medium and high priority.

scholarly journals The Impact of BNDES’s Financial Resources on the Market Value of B3-Listed Companies

2021 ◽  
Vol 24 (1) ◽  
pp. 20
Author(s):  
João José Ferreira Simões ◽  
Vitor Gonçalves De Souza ◽  
Rafael Cortezão De Mello ◽  
Antônio Artur De Souza ◽  
Bruno Pérez Ferreira
Keyword(s):  
Financial Support ◽  
Stock Exchange ◽  
Panel Data Analysis ◽  
Market Value ◽  
Financing Policy ◽  
Full Sample ◽  
Financial Scandals ◽  
One Step ◽  
The One ◽  
The Impact

Objective: Analyze whether Brazilian Development Bank (BNDES) financial support have increased Brazilian companies market value using a sample comprising 272 observations from 40 companies listed at B3 Stock Exchange, in 2003–2018.Method: Panel data analysis using the One-step system GMM and a non-parametric Kruskal-Wallis H test followed by a Dunn test.Relevance: The relevance of the current study is in its analysis of a possible association between BNDES-granted financing and changes in Brazilian companies’ market value.Results: We did not observe that the financial support from BNDES could be associated with an increase in the market value of the companies. It was not possible to establish a causal relationship with respect to the financial support of BNDES and an impact on the corporate market value when we analyzed our full sample. However, we observe the existence of difference in the averages of the corporate market value when we analyzed in groups of companies. This result is not in line with recent financial scandals in Brazil involving companies that had obtained BNDES funding.Theoretical Contributions: Our findings may assist in the elaboration of an efficient policy to finance Brazilian companies, as the analysis of BNDES performance is fundamental to determining whether the applicability of Brazilian financing policy has reached the proposed results.

Natural Rubber-Toughened Polystyrene: Effects of Mixing Procedure and Maleic Anhydride Content on Impact Property and Phase Morphology

2013 ◽  
Vol 747 ◽  
pp. 607-610 ◽  
Author(s):  
Saravalee Saengthaveep ◽  
Sadhan C. Jana ◽  
Rathanawan Magaraphan
Keyword(s):  
Maleic Anhydride ◽  
Natural Rubber ◽  
Impact Energy ◽  
Rubber Particle ◽  
Melt Blending ◽  
Gel Content ◽  
Rubber Toughened ◽  
One Step ◽  
The One ◽  
The Impact

The toughening of polystyrene (PS) by melt blending with natural rubber (NR) was prepared in a brabender plasticorder. Two kinds of processing had been used: (a) one-step mixing in which the three components of PS (60 wt%), NR (40 wt%) and maleic anhydride (MA) were simultaneously introduced in the mixer; (b) two-step mixing in which NR and MA were separately premixed before the final mixing with PS. The effect of MA loading (3 and 5 phr) on gel content, impact energy and morphology of PS-NR-MA blend were further investigated. The results showed that the incorporation of NR into PS increased the impact energy of the blend. The results also showed a significant effect of the different mixing procedures on the properties of PS-NR-MA blend. High contents of unreacted MA and gel were found in the blend obtained by the one-step mixing, whereas the blend prepared by the two-step mixing showed lower values in both unreacted MA and gel content. On the other hand, the impact energy of the blend prepared by one-step mixing was slightly higher than that of the blend prepared by two-step mixing. This is due to the decreased molecular weight of NR in the formerly prepared MNR of the two-step mixing. For the effect of MA loading, the decrease of unreacted MA content, gel content and rubber particle size were found at low concentration of MA.

Impact of optimizing pre-analytical phase on the diagnosis of gestational diabetes and related outcomes

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Dominika Szoke ◽  
Simona Borille ◽  
Manuela Cardellicchio ◽  
Giovanna Spadaccini ◽  
Emanuela Taricco ◽  
...  
Keyword(s):  
Gestational Diabetes ◽  
Perinatal Outcomes ◽  
Tolerance Test ◽  
Large For Gestational Age ◽  
Oral Glucose ◽  
One Step ◽  
Analytical Phase ◽  
The One ◽  
The Impact ◽  
Higher Sensitivity

Abstract Objectives Pre-analytical plasma glucose (PG) sampling methodology may significantly affect gestational diabetes mellitus (GDM) incidence, but no studies directly examined the impact on perinatal outcomes. We compared the effect on oral glucose tolerance test (OGTT) results of using for blood sampling the traditional sodium fluoride (NaF) tubes, batched at controlled temperature, and the more effective citrate-buffered tubes, in terms of GDM diagnosis and related outcomes. Methods We evaluated 578 pregnant women performing OGTT between 24- and 28-weeks’ gestation. Paired NaF and citrate blood samples were drawn and analyzed for PG. GDM diagnosis was made by applying the ‘one-step’ American Diabetes Association strategy. Data on perinatal outcomes were collected in a subset of 330 women who delivered in our hospital network. Results Using the standard NaF approach, 69 (11.9%) GDM women were detected. Using citrate PG values, 90 women were additionally identified as GDM, increasing the GDM prevalence to 27.5%. Perinatal outcomes were analyzed according to the different diagnostic allocation (NaF-diagnosed GDM, additional citrate-diagnosed GDM, and no GDM). NaF-diagnosed GDM showed a higher incidence of large for gestational age (LGA) (p=0.034), and of cesarean and preterm delivery (p<0.01) vs. no GDM. The only outcome remaining more frequent in the additional citrate diagnosed GDM when compared with no GDM group was LGA (17.2 vs. 6.8%, p=0.025). Conclusions If a health care system plans to use citrate tubes for GDM diagnosis, considerations about clinical implications are mandatory by balancing higher sensitivity in detecting a poor glycemic control with effects on outcomes to avoid “overdiagnosis”.

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