bluuebunny/crossref_metadata_2025 huggingface dataset:
TAS2R38 bitter taste receptor and attainment of exceptional longevity
Authors: Melis Melania , Errigo Alessandra , Crnjar Roberto , Pes Giovanni Mario , Tomassini Barbarossa Iole
Published: December 2019

Bitter taste receptors play crucial roles in detecting bitter compounds not only in the oral cavity, but also in extraoral tissues where they are involved in a variety of non‒tasting physiological processes. On the other hand, disorders or modifications in the sensitivity or expression of these extraoral receptors can affect physiological functions. Here we evaluated the role of the bitter receptor TAS2R38 in attainment of longevity, since it has been widely associated with individual differences in taste perception, food preferences, diet, nutrition, immune responses and pathophysiological mechanisms. Differences in genotype distribution and haplotype frequency at the TAS2R38 gene between a cohort of centenarian and near-centenarian subjects and two control cohorts were determined. Results show in the centenarian cohort an increased frequency of subjects carrying the homozygous genotype for the functional variant of TAS2R38 (PAV/PAV) and a decreased frequency of those having homozygous genotype for the non-functional form (AVI/AVI), as compared to those determined in the two control cohorts. In conclusion, our data providing evidence of an association between genetic variants of TAS2R38 gene and human longevity, suggest that TAS2R38 bitter receptor can be involved in the molecular physiological mechanisms implied in the biological process of aging.
Concurrent administration of IFNα14 and cART in TKO-BLT mice enhances suppression of HIV-1 viremia but does not eliminate the latent reservoir
Authors: Sutter Kathrin , Lavender Kerry J. , Messer Ronald J. , Widera Marek , Williams Katie , Race Brent , Hasenkrug Kim J. , Dittmer Ulf
Published: December 2019

Combination antiretroviral therapy (cART) prevents HIV-1 replication but does not eliminate the latent reservoir and cure the infection. Type I interferons (IFN) mediate antiviral effects through different mechanisms than cART. We previously showed that IFNα14 is the most potent IFNα subtype against HIV-1 and that it can significantly reduce the HIV-1 proviral reservoir. This study sought to determine whether combining cART with IFNα14 therapy would produce greater reductions in HIV-1 viral and proviral loads than ART alone. Immunodeficient Rag2−/−γc−/−CD47−/− C57BL/6 mice were humanized by the BLT method, infected with HIV-1JR-CSF and the in vivo efficacy of cART was compared with combined cART/IFNα14 therapy. Infection was allowed to establish for 6 weeks prior to 4 weeks of treatment with oral cART either with or without IFNα14. Plasma viral RNA and splenic CD4+ T cell viral DNA levels were measured immediately after treatment and after 2 weeks of therapy interruption. Augmentation of cART with IFNα14 resulted in significantly enhanced suppression of HIV-1 plasma viremia. However, no significant reduction in total viral DNA was detectable. Furthermore, virus rebounded after treatment interruption to similar levels in both groups. Thus, augmentation of cART with IFNα14 resulted in a more pronounced reduction of HIV viremia levels over cART alone, but the effect was not potent enough to be detected at the viral DNA level or to prevent virus rebound following therapy interruption in immune system-humanized mice.
Enhancing the corrosion resistance of reinforcing steel under aggressive operational conditions using behentrimonium chloride
Authors: Radwan A. Bahgat , Sliem Mostafa H. , Yusuf Noor S. , Alnuaimi Nasser A. , Abdullah Aboubakr M.
Published: December 2019

Aggressive operational conditions e.g. saline media and acidic gases, e.g., CO2can increase the corrosion rate of reinforcing steel. Accordingly, the necessity to protect the steel under the above conditions without affecting the mechanical properties of the concrete is growing. Herein, the inhibition efficiency of a new corrosion inhibitor, behentrimonium chloride (BTC, C25H54ClN), is explored in a simulated-concrete pore solution (SCP) with 3.5 wt.% NaCl at different pH using electrochemical impedance spectroscopy (EIS) and polarization methods. Using only a 50 μmol L−1of BTC, we are able to measure an inhibition efficiency of 91, 79, and 71% in SCP solution with 3.5% NaCl at pH of 12.5, 10 and 7, respectively without showing any effect on the mechanical properties on the cured mortars. Temkin isotherm is used to describe the physisorption of BTC inhibitor on the steel surface. Also, the adsorption and influence of the inhibitor on the metal surface are characterized using the scanning electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. In conclusion, this new inhibitor shows high corrosion inhibition efficiencies under different aggressive conditions and can be used in concrete to reduce the corrosion rate of reinforcing steel without decreasing the mechanical properties of the concrete.
Plug-and-Play In Vitro Metastasis System toward Recapitulating the Metastatic Cascade
Authors: Ni Bing-Syuan , Tzao Ching , Huang Jen-Huang
Published: December 2019

Microfluidic-based tumor models that mimic tumor culture environment have been developed to understand the cancer metastasis mechanism and discover effective antimetastatic drugs. These models successfully recapitulated key steps of metastatic cascades, yet still limited to few metastatic steps, operation difficulty, and small molecule absorption. In this study, we developed a metastasis system made of biocompatible and drug resistance plastics to recapitulate each metastasis stage in three-dimensional (3D) mono- and co-cultures formats, enabling the investigation of the metastatic responses of cancer cells (A549-GFP). The plug-and-play feature enhances the efficiency of the experimental setup and avoids initial culture failures. The results demonstrate that cancer cells tended to proliferate and migrate with circulating flow and intravasated across the porous membrane after a period of 3 d when they were treated with transforming growth factor-beta 1 (TGF-β1) or co-cultured with human pulmonary microvascular endothelial cells (HPMECs). The cells were also observed to detach and migrate into the circulating flow after a period of 20 d, indicating that they transformed into circulating tumor cells for the next metastasis stage. We envision this metastasis system can provide novel insights that would aid in fully understanding the entire mechanism of tumor invasion.
OPN promotes the aggressiveness of non-small-cell lung cancer cells through the activation of the RON tyrosine kinase
Authors: Hao Chengcheng , Cui Yuxin , Chang Siyuan , Huang Jing , Birkin Emily , Hu Mu , Zhi Xiuyi , Li Wenbin , Zhang Lijian , Cheng Shan , Jiang Wen G.
Published: December 2019

Osteopontin (OPN) is identified as a diagnostic and prognostic biomarker of tumor progression and metastasis. In non-small-cell lung cancer (NSCLC), the functions of OPN have not been well characterized. The current study sought to investigate the clinical implications of OPN expression in NSCLC and the role of OPN in the aggressiveness of the lung cancer cells. Using a proteomics approach, we identified that phospho-RON (p-RON) was one of the most remarkably up-regulated proteins in OPN-overexpressing cells. The levels of OPN and RON transcripts were unveiled as independent prognostic indicators of survival in NSCLC (p = 0.001). Higher levels of OPN, RON and p-RON proteins were observed in tumor tissues. Knock down of the OPN gene suppressed the migration and invasion abilities of the A549 lung cancer cells which endogenously expresses OPN. While ectopic expression of OPN in the SK-MES-1 lung cancer cells increased levels of cellular invasion and migration. In addition, these changes were accompanied by a phosphorylated activation of RON. Small-molecule inhibition of RON or siRNA silencing of RON significantly reduced OPN-induced migration and invasion of lung cancer cells and had an inhibitory effect on the OPN-mediated cell epithelial-mesenchymal transition. Our study suggests that in NSCLC, the aberrant expression of OPN can be considered as an independent survival indicator and is associated with disease progression. OPN plays a crucial role in promoting migration and invasion properties of lung cancer cells through its phosphorylation activation of the RON signaling pathway, implying its potential as a therapeutic target in the treatment of NSCLC.
Publisher Correction: Pattern analysis of 532- and 1,064-nm picosecond-domain laser-induced immediate tissue reactions in ex vivo pigmented micropig skin
Authors: Lee Hee Chul , Childs James , Chung Hye Jin , Park Jinyoung , Hong Jumi , Cho Sung Bin
Published: December 2019

An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Effect of treatment atmosphere on the vanadium species of V/TiO2 catalysts for the selective catalytic reduction of NOx with NH3
Authors: Lian Zhihua , Xin Shaohui , Zhu Na , Wang Qiang , Xu Jun , Zhang Yan , Shan Wenpo , He Hong
Published: December 2019

The decrease of polymeric vanadyl species due to treatment under different atmospheres results in the reduction of NH3-SCR activity.
Photodegradation of volatile organic compounds catalyzed by MCr-LDHs and hybrid MO@MCr-LDHs (M = Co, Ni, Cu, Zn): the comparison of activity, kinetics and photocatalytic mechanism
Authors: Meng Yue , Dai Tiantian , Zhou Xiaobo , Pan Guoxiang , Xia Shengjie
Published: December 2019

The efficient removal of high-concentration volatile organic compounds (VOCs) has been a challenging task.
9t18:1 and 11t18:1 activate the MAPK pathway to regulate the expression of PLA2 and cause inflammation in HUVECs
Authors: Hu Sheng-Ben , Zou Qian , Lv Xin , Zhou Ruo-Lin , Niu Xian , Weng Chen , Chen Fang , Fan Ya-Wei , Deng Ze-Yuan , Li Jing
Published: December 2019

transfatty acids (TFAs) have been reported to promote vascular diseases mainly by promoting apoptosis and inflammation of vascular endothelial cells.
1% defect enriches MoS2 quantum dot: catalysis and blue luminescence
Authors: Tang Jingmin , Sakamoto Masanori , Ohta Haruhisa , Saitow Ken-ichi
Published: December 2019

MoS2 quantum dot, given by laser ablation, have 1% sulfur vacancies quantified by ESR as a functional defect. Very good catalyst, the shortest synthesis time, and room-temperature process are achieved against the top 10 papers of the HER of MoS2.
Coupling of a conductive Ni3(2,3,6,7,10,11-hexaiminotriphenylene)2 metal–organic framework with silicon nanoparticles for use in high-capacity lithium-ion batteries
Authors: Nazir Aqsa , Le Hang T. T. , Min Chan-Woo , Kasbe Arvind , Kim Jaekook , Jin Chang-Soo , Park Chan-Jin
Published: December 2019

A composite of Si nanoparticles and a two dimensional porous conductive Ni3(2,3,6,7,10,11-hexaiminotriphenylene)2 (Ni3(HITP)2) metal–organic framework (MOF), namely Si/Ni3(HITP)2, is suggested as a potential anode material for Li-ion batteries.
Layer-by-layer assembly of magnetic-core dual quantum dot-shell nanocomposites for fluorescence lateral flow detection of bacteria
Authors: Wang Chongwen , Shen Wanzhu , Rong Zhen , Liu Xiaoxian , Gu Bing , Xiao Rui , Wang Shengqi
Published: December 2019

A highly sensitive and quantitative fluorescent lateral flow strip is proposed for bacterial detection by using novel magnetic-core@dual QD-shell nanoparticles as multifunctional fluorescent labels.
Water–DMSO-promoted one-pot synthesis of two new series of dihydropyrrolo[2,3-h]quinolines
Authors: Liao Hui , Zhu Qiuhua
Published: December 2019

Two new series of dihydropyrrolo[2,3-h]quinolines 4 and 6 were synthesized via a three-component reaction synergistically activated by water and DMSO, and new pyrrolo[2,3-h]quinolines 10 can be obtained by oxidation of 4 using Cu(NO3)2 as oxidant.
Mechanochemical changes on cyclometalated Ir(iii) acyclic carbene complexes – design and tuning of luminescent mechanochromic transition metal complexes
Authors: Han Jingqi , Tang Kin-Man , Cheng Shun-Cheung , Ng Chi-On , Chun Yuen-Kiu , Chan Shing-Lun , Yiu Shek-Man , Tse Man-Kit , Roy Vellaisamy A. L. , Ko Chi-Chiu
Published: December 2019

A new class of luminescent cyclometalated Ir(iii) complexes with readily tunable mechanochromic properties derived from the mechanically induced trans-to-cis isomerization have been developed.
Coexistence of normal and inverse deuterium isotope effects in a phase-transition sequence of organic ferroelectrics
Authors: Horiuchi Sachio , Ishibashi Shoji , Kobayashi Kensuke , Kumai Reiji
Published: December 2019

Deuterium substitutions of the hydrogen-bonded ferroelectrics smoothly raise the Curie point and simultaneously reduce other phase-transition temperatures by a few tens of degrees.
High pressure extraction of bioactive diterpenes from the macroalgae Bifurcaria bifurcata: an efficient and environmentally friendly approach
Authors: Pais Adriana C. S. , Pinto Carlos A. , Ramos Patrícia A. B. , Pinto Ricardo J. B. , Rosa Daniela , Duarte Maria F. , Abreu M. Helena , Rocha Silvia M. , Saraiva Jorge A. , Silvestre Armando J. D. , Santos Sónia A. O.
Published: December 2019

Bioactive linear diterpenes were selectively extracted from the macroalga Bifurcaria bifurcata through optimized high-pressure extraction.
A novel in situ N2 generation system assisted by authigenic acid for formation energy enhancement in an oilfield
Authors: Qian Cheng , Wang Yefei , Yang Zhen , Qu Zhengtian , Ding Mingchen , Chen Wuhua , He Zhenpei
Published: December 2019

A novel in situ N2 generation system with authigenic acid can enhance the gas production volume and gas-generating efficiency at high temperatures.
Atomic-level understanding of interface interactions in a halloysite nanotubes–PLA nanocomposite
Authors: Kruglikov Alexander , Vasilchenko Andrey , Kasprzhitskii Anton , Lazorenko Georgy
Published: December 2019

The mechanism of bond formation between PLA and outer, inner and edge surfaces of HNT was established.
Reversible RNA acylation for control of CRISPR–Cas9 gene editing
Authors: Habibian Maryam , McKinlay Colin , Blake Timothy R. , Kietrys Anna M. , Waymouth Robert M. , Wender Paul A. , Kool Eric T.
Published: December 2019

We report the development of post-transcriptional chemical methods that enable control over CRISPR–Cas9 gene editing activity both in in vitro assays and in living cells.
Regulatory networks of circRNAs related to transcription factors in Populus euphratica Oliv. heteromorphic leaves
Authors: Bao Lianghong , Qin Shaowei , Li CaiLin , Guo Zhongzhong , Zhao Lifeng
Published: December 2019

Circular RNAs (circRNAs) are a novel class of non-coding RNAs that are characterized by a covalently closed circular structure. They have been widely found in Populus euphratica Oliv. heteromorphic leaves (P. hl). To study the role of circRNAs related to transcription factors (TFs) in the morphogenesis of P. hl, the expression profiles of circRNAs in linear, lanceolate, ovate, and broad-ovate leaves of P. euphratica were elucidated by strand-specific sequencing. We identified and characterized 22 circRNAs related to TFs in P. hl at the four developmental stages. Using the competing endogenous RNAs hypothesis as a guide, we constructed circRNA–miRNA–TF mRNA regulatory networks, which indicated that circRNAs antagonized microRNAs (miRNAs), thereby influencing the expression of the miRNA target genes and playing a significant role in transcriptional regulation. Gene ontology annotation of the target TF genes predicted that these circRNAs were associated mainly with the regulation of leaf development, leaf morphogenesis, signal transduction, and response to abiotic stress. These findings implied that the circRNAs affected the size and number of cells in P. hl by regulating the expression of TF mRNAs. Our results provide a basis for further studies of leaf development in poplar trees.
Numerical simulation of turbulence model based on building energy enthalpy
Authors: Shi Xin , Lu Weiding , Zhao Ying , Fu Jialei
Published: December 2019

Temperature and humidity play an extremely important role in indoor thermal comfort and industrial production. To achieve precise control of temperature and humidity in the building space environment and reduce energy consumption, it is necessary to analyse turbulence from the perspective of energy. On the basis of the basic principle of building energy enthalpy, under the premise of reasonable assumptions of various boundary conditions, four turbulence models were established for simulation. The basic characteristics, overall distribution and local characteristics of the interior energy enthalpy were compared and analysed. The theory of building energy enthalpy not only can effectively solve the influence of latent heat on the building environment, but also can provide guidance on the selection strategy of turbulence models. The proposed theory can improve the accuracy and credibility of the simulation data of building space.
Calibration and orientation of industrial online photogrammetry systems in situ
Authors: Sun Peng , Lu Naiguang , Dong Mingli , Wang Jun , Yan Bixi
Published: December 2019

This study proposes an analytical method for calibrating and orienting online photogrammetric systems using a scale bar. The primary idea is building control lengths in the measurement volume by moving and rotating the scale bar and then conducting a self‐calibration bundle adjustment using images of the control lengths. In this study, the five‐point relative orientation method is used to provide estimations of the exterior camera parameters. Additionally, this study elaborates the model of the lengths constrained self‐calibration bundle adjustment, the block computation algorithm and the accuracy assessment. This method obtains both the interior and the exterior orientation parameters of the two cameras, and provides spatial bar length reconstruction precision as the performance evaluation. Simulations are conducted to analyze the calibration accuracy and the results show that the method achieves comparable accuracy and precision against the state‐of‐the‐art method. However, the method does not need steady and well distributed 3D points and is easy to operate. Real data experimental results show that the maximum length measurement error of this method in a volume of 5 m × 4 m × 2 m is <0.4 mm.
Enhanced UV radiation and dense clumps in the molecular outflow of Mrk 231
Authors: Cicone Claudia , Maiolino Roberto , Aalto Susanne , Muller Sebastien , Feruglio Chiara
Published: December 2019

We present interferometric observations of the CN(1–0) line emission in Mrk 231 and combine them with previous observations of CO and other H2 gas tracers to study the physical properties of the massive molecular outflow. We find a strong boost of the CN/CO(1–0) line luminosity ratio in the outflow of Mrk 231, which is unprecedented compared to any other known Galactic or extragalactic astronomical source. For the dense gas phase in the outflow traced by the HCN and CN emissions, we infer XCN ≡ [CN]/[H2]> XHCN by at least a factor of three, with H2 gas densities of nH2 ∼ 105−6 cm−3. In addition, we resolve for the first time narrow spectral features in the HCN(1–0) and HCO+(1–0) high-velocity line wings tracing the dense phase of the outflow. The velocity dispersions of these spectral features, σv ∼ 7−20 km s−1, are consistent with those of massive extragalactic giant molecular clouds detected in nearby starburst nuclei. The H2 gas masses inferred from the HCN data are quite high, Mmol ∼ 0.3−5 × 108 M⊙. Our results suggest that massive complexes of denser molecular gas survive embedded into the more diffuse H2 phase of the outflow, and that the chemistry of these outflowing dense clouds is strongly affected by UV radiation.
Building Multi-Material components by Direct Laser Deposition
Authors: Perini Matteo , Amirabdollahian Sasan , Bosetti Paolo
Published: December 2019

Most mechanical components are usually made of a single material, as a compromise between chemical, physical and functional properties. When designing an object, the choice of one material over another is driven by many reasons. Sometimes these reasons are not strictly technical, including for instance: biocompatibility, density, weldability, corrosion resistance, price, and appearance. Direct Laser Deposition (DLD) technology is an additive manufacturing process that allows the construction of objects by depositing material layer by layer. With DLD, the metal powder comes out of a nozzle conveyed by a flow of inert gas and is melted by a laser beam. One of the advantages of this technology over other AM technologies (such as SLM) is that it is possible to vary the composition of the deposited material by simply changing the metal powder. It is clear that with DLD technology, the properties of different metallic materials deposited together in a single object can be exploited. With this work the authors present two real-life case studies, in which the DLD technology is used to build multi-material components. Thefirst case concerns a gearbox component made of C40 steel that must work in a food environment and has therefore been completely covered with a layer of stainless steel. The second case is a flange that must have a weldable base, while the internal hole must be made of a high-performance tool-steel.
Sweat glands module with integrated sensors designed for Additive Manufacturing
Authors: Turcin Ioan , Abdallah Ali , Cosma Cosmin , Thiebet Thomas , Zavec Daniela , Balc Nicolae
Published: December 2019

Lead by the results of our previous work, in which we designed the sweat glands prototype according to AM (Advanced Manufacturing) requirements, in this study we aimed to integrate the previously manufactured channels into a stereolithography (SLA)-manufactured module, in order to avoid support structures inside the channels and the model cavities. That was achieved by distributing the channels in the manner which approximates the sweat glands distribution on an equivalent real body part and to be able toadjust the sweat quantity, to the estimated sweat rates found in the literature. The manufactured module has integrated humidity and temperature sensors, which will allow an accurate quantitative assessmentof the thermoregulation of the individual modules and the sweat glands prototype as a whole.
Group technology in the flexible manufacturing system
Authors: Kostal Peter , Mudrikova Andrea , Michal David.
Published: December 2019

Flexible manufacturing systems enable rapid changes in production. These changes may be due to changes in the product itself, such as different variations of the product or changes in conditions in the production itself. Currently, most products are designed on a computer using a variety of CAD software. Using sophisticated CAD tools, the resulting 3D product model can include not only the geometric product data but the process plan and technology data. Group technology is very often used to quickly create a technological process. Where, based on similarity, parts are assigned to individual groups and each group has the same basis for the technological process.
VR 3D Education for Vocational Training
Authors: Maricic Sven , Radolovic Donald , Veljovic Ivan , Raguz Roberta
Published: December 2019

The progress and development in the fields of technologies in the past few decades are impressive. With so many innovations that have had an impact on human lives and have changed them so drastically, living in a time where new technologies are still making massive changes, and, unquestionably, it wil continue with that trend. As the techniques are continuously evolving, people are forced to prepare ourselves and our descendants to the new and upcoming technologies so that they would be able to understand them, use them, teach others about them and also make some improvements in the specific fields of applications. This article presents an overview of the principal results of research on the impact of Virtual Reality (VR) 3D education for students in industrial vocational training. They were introducedto the generated model and had to explore all elements to have personal experience in the virtual environment. After the training, a user experience survey has been conducted, and the results obtained after the use of the system were presented.
Optimisation of production processes with the use of the modelling and simulation method
Authors: Plinta Dariusz , Grznar Patrik
Published: December 2019

The paper presents an application of the modelling and simulation method for finding an optimum solution related to designing production processes. Using simulation in connection with optimization makes it possible to check almost all admissible variants of the proposed improvements comparatively quickly in order to evaluate them and to choose the best solution. The paper presents how a simulation model is created and shows an example of multi-criteria optimization.
Parametrised Design of a Cutting Device Used for High Tibial Osteotomy
Authors: Cofaru Nicolae Florin , Cofaru Ileana Ioana , Petruse Radu Emanuil , Rackov Milan , Blagojevic Mirko , Marjanovic Nenad
Published: December 2019

In this paper we present a design method for a modular device used in different types of HIGH TIBIAL OSTEOTOMY surgical procedures. The requirements, necessities and functions of this modular device are presented in the first part of the article. An important aspect is the fact that the device must be designed in a manner which permit to use it for all types of HIGH TIBIAL OSTEOTOMY: opening wedge osteotomies, closing wedge osteotomies, medial osteotomies, lateral osteotomies, uniplanar osteotomies or biplanar osteotomies. This fact is possible using modular elements for the main parts of the devices. The researches could be the starting point for others researches regarding the appropriate materials and the possibility to execution customized several parts of the modular device using Additive Manufacturing facilities.
Influence of Coolant Pressure Size on Surface Roughness when Stainless Steel Machining
Authors: Cep Robert , Cepova Lenka , Borzan Cristina Stefana , Kasal Jiri , Sadilek Marek , Sokova Dagmar , Hatala Michal , Petru Jana , Stancekova Dana , Pagac Marek , Hajnys Jiri , Mizera Ondrej
Published: December 2019

The paper is focused on the influence of the coolant pressure on the surface roughness of the workpiece when machining stainless steels. The components were machined on a STAR SR-32J dual spindle machining center and an external cooling unit HYTEK CHAV 160/150-AF-F-OL was used for cooling. Two stainless steel components were investigated, namely the gas control valve rod and the high-pressure control valve housing, which require low roughness Ra after machining (less than 0.375 and 0.25 micrometers respectively). The first component was tested at 8 different pressures in the range of 150 bar - 10 bar and the second component at 4 different pressures in the range of 120 bar - 10 bar. The roughness parameters were measured by the contact method using the MITUTOYO Surftest SJ-410 Roughness Tester and the Alicona InfiniteFocus optical microscope. Based on these sample input parameters, it was evaluated howmuch the pressure affects the surface quality or suggested its reduction due to the high cost of operation of the external high-pressure equipment.
Risk Assessment of Physical Security within a Technologized Knowledge Based Organization
Authors: Țîțu Mihail Aurel , Pop Alina Bianca , Ceocea Costel
Published: December 2019

The purpose of this scientific paper is to support the decisionmaking process on the risk management based on the results of an analysis and subsequently on the risks hierarchy. This assessment involves the comparison of the level of risk determined by the analysis with the risk criteria developed in the context of the establishment phase. This scientific paper on assessing and treating risks to physical security has been developed to identify, assess and quantify the associated risk in a technologizedknowledge-based organization. The basis of this study on the assessment and treatment of risks to physical security is to identify specific potential risks as well as the emergency response procedures. Effective risk assessment involves assessing the likelihood and impact of a risk-based event, and based on the determined values, determine the risk profile and treatment priorities. The determined risk level is assimilated to risk exposure.
Study and Performance Improvement of the Drive Systems for a Class of Machine Tools
Authors: Mikhov Mikho , Zhilevski Marin
Published: December 2019

This paper deals with some problems in the modernization of a type of machine tools with multi–coordinate drive systems. The basic requirements to the drives of each coordinate axis and the spindle are presented. Using the analysis carried out, a practical approach to appropriate selection of the respective drives is applied. The methodology offered is illustrated with some examples for choice of drives with direct current and alternating current motors. Some experimental research of cases with different feed and spindle drives are described and discussed. Better capabilities of the modernized machines for processing more complex workpieces are achieved, at a relatively low price. This research and the obtained results can be used in the design and tuning of electric drives for the considered type of machines with numerical program control.
Using Carbon-fibre Reinforcement with a 5-axis Material Extrusion System
Authors: Kaill Nathaniel , Pradel Patrick , Bingham Guy , Campbell R Ian
Published: December 2019

One of the main limitations of material extrusion (ME) components is their anisotropic mechanical behaviour, mainly due to the poor bonding between layers. 5-axis ME has the capability to orientate theprint layers in line with loading conditions, in order to limit the effect of poor inter-laminar bonding. Previous work has demonstrated how aligning deposited material in the same direction as the dominant stresses can improve a part’s mechanical performance. When fibre-reinforcement is added to theseoriented layers, the stiffness and strength of parts should increase further. This paper presents a comparison between 5-axis parts that were printed in pure poly-lactic acid (PLA) and in carbon-fibrereinforced (CFR) PLA. Sets of dome-shaped components were built using several different build strategies and tested for compressive stiffness and strength. The results were rather mixed but did show a marked improvement in compressive strength under certain conditions. Further work is required to understand one of the failure mechanisms that was seen and to overcome some of the limitations of the 5-axis machine currently being used. The work was undertaken to support the Directional Composites through Innovative Manufacturing (DiCoMI) project, funded by the European Commission.
Finite element simulation of delamination process in composite materials
Authors: Sabău Emilia , Vilău Cristian , Bere Paul , Popescu Adrian
Published: December 2019

The delamination phenomenon is undesirable and constitutes a major problem. In this paper, a study of delamination for composite materials reinforced with unidirectional glass fibers in polyester matrix is analyzed. The composite plates were made using two manufacturing technologies, hand lay-up and compression hand lay-up process. The study found out the maximum value of the force where delamination occurs and the specific delamination resistance. Also, it’s done a finite element simulation of delamination process at polymeric composite materials under transverse loads. The propagation model ofdelamination was implemented in finite element ANSYS software. There are presented the used materials for samples, the manufacturing process, laboratory equipment and the experimental results.
Mechanical and structural properties of composites made from recycled and virgin polyethylene terephthalate (PET) and metal chip or mesh wire
Authors: Rusu Mircea Aurelian Antoniu , Radu Sever-Adrian , Moldovan Catalin , Sarosi Codruta , Mazilu (Moldovan) Ionela Amalia , Rusu Laura Monica
Published: December 2019

Although polyethylene terephthalate (PET) is a champion of recycling, intense research is being done to find new solutions for using recycled plastic. This study aims to characterize the mechanical andstructural properties (SEM- scanning electron microscopy) of products made from recycled metal swarf or mesh wire with recycled plastic (PET) in comparison with virgin plastic. Samples manufactured from virgin and recycled PET are made by pressing and high temperature. The loss of mechanical properties ofproducts made from recycled plastic is a major drawback that influences their use. SEM images confirm that the dispersion and distribution of the PET phase is not very uniform. By addition of virgin plastic in various compositions with recycled plastic, processing parameters and mechanical properties can be optimized.
Fatigue of thin periodic triangular lattice plates
Authors: Li Yifan , Shterenlikht Anton , Pavier Martyn , Coules Harry
Published: December 2019

A method for predicting the fatigue life of triangular lattices is proposed in this paper by considering fatigue properties of single lattice struts. Fatigue tests of different sizes of lattice plates of aluminium alloy, and tests of single struts with different maximum fluctuating loads, have been conducted to validate this method. It is found that the struts in a triangular lattice break near to strut intersections, where stress and strain concentrations occur. Similar crack propagation paths were observed in different lattice plate specimens: the cracks grew at a 30° angle to the initial edge crack in the upper half of lattice plate. The mixed-mode fatigue crack propagation rate was also studied and expressed using an effective stress intensity factor. A size effect on the crack growth rate of triangular lattice plates was also observed: a fatigue crack will propagate slightly quicker in larger triangular plates than in smaller ones.
Mechanical response of a Laser Cladding repaired structure: localization of plastic strain due to microstructure gradient
Authors: Guévenoux Camille , Hallais Simon , Charles Alexandre , Charkaluk Eric , Constantinescu Andrei
Published: December 2019

Laser Cladding is an additive manufacturing technology enabling to repair complex metallic components by removing the worn region and reconstructing locally the initial geometry. The aim of this work is to study the mechanical response of Inconel 718 repaired thin walls. More precisely, we perform an EBSD imaging and in-situ SEM tensile tests on specimen whose gauge section contains the interface between base material and repaired area. We observe the multiaxial strain patterns until failure at the grain level using a Digital Image Correlation method and superpose this pattern with the microstructure gradient induced by repair. The observations highlight a strain localization phenomenon in repaired structures mainly due to grain size eﬀect.
Multiaxial fatigue strength under non-proportional loading of additively manufactured notched components of Ti-6Al-4V
Authors: Bressan Stefano , Razavi Javad , Ogawa Fumio , Itoh Takamoto , Berto Filippo
Published: December 2019

In this study fatigue tests have been conducted on additively manufactured notched specimens made of titanium alloy Ti-6Al-4V under uniaxial loading and multiaxial non-proportional loading. Laser powder bed fusion technique has been employed to fabricate cylindrical specimens which have been successively machined to obtain a circumferential notch. Four varieties of specimens were fabricated depending on the build orientation and the application of a post-fabrication stress-relief heat treatment. The influence of layer orientation and heat treatment on the material microstructure has been analyzed. Strain controlled tests were performed with both proportional loading represented by a push-pull strain path and non-proportional loading represented by a circle strain path. The number of cycles to failure under both proportional and non-proportional loadings seemed not depending on layer orientation and heat-treatment. The cyclic plastic behavior of the material has been verified through the observation of the softening and hardening curves. The surface of the crack has been finally analyzed to verify the crack initiation position which has been detected on voids or defects located in the vicinity of the notch tip.
Multiaxial fatigue criteria applied to motor crankshaft in thermoelectric power plants
Authors: Pereira Marcos Venicius S. , Darwish Fathi Aref , Feiferis André , Lima Castro Tiago
Published: December 2019

Fatigue failures of motor crankshafts operating in thermoelectric power plants have recently been reported. Stress fields provided by finite element calculations at critical points of a crankshaft that failed in service are used to test the structural integrity of the component. Taking into account the fact that the stresses acting at a given point are most likely out of phase, multiaxial fatigue criteria based on the von Mises stress are considered to be most suitable for predicting the fatigue behavior of the crankshaft. Using the von Mises stress, it was also possible to apply octahedral shear stress-based criteria and the results obtained have indicated that the crankshaft made of DIN 34CrNiMo6 steel should not suffer fatigue failure under the action of the stress fields in question. However, such failures have been occurring and this apparent discrepancy is presented and briefly discussed in the present study.
Multiaxial Fatigue Behavior of High-Density Polyethylene (HDPE) Including Notch Effect: Experiments and Modeling
Authors: Amjadi Mohammadreza , Fatemi Ali
Published: December 2019

High-Density Polyethylene (HDPE) is used in many industries with many applications from automotive industry to biomedical implants. It can be manufactured using different processing techniques including compression molding, injection molding, and blow molding. Multiaxial loading and non-proportionality between different loading sources are inevitable in many applications. It is shown that the common multiaxial fatigue criteria such as von Mises equivalent stress are not able to correlate the multiaxial fatigue data. In this study, multiaxial fatigue behavior of neat HDPE is investigated using hollow tubular specimens through experimental fatigue tests. Axial, torsion, and combined in phase and out-of-phase axial-torsion fatigue tests were conducted. Stress concentration effect on multiaxial fatigue behavior was also studied. Experimental results and analytical models used to account for the aforementioned effects are presented and discussed in this paper.
Blind prediction of FRP repairs for multiaxial fatigue cracks on Hydraulic Steel Structures
Authors: Alberto Riveros Guillermo , Michelle Lozano Christine
Published: December 2019

Currently, over 80% of the navigation steel structures (NSS) within the United States’ inland waterway system have reached or exceeded their useful design life. Age has caused deterioration of the design boundary conditions (e.g. diagonal relaxation and quoin block deterioration) leading to overloads and causing multi-axial fatigue cracking. Furthermore, corrosion and deterioration of the protective system accelerate the fatigue crack growth rate. This paper presents numerical experiments to evaluate the viability of fiber reinforce polymer (FRP) retrofit methods as an alternative to repair mix-mode fatigue cracking. The numerical experiments use a combination of tension, shear, and bending forces to develop different cracking patterns. Afterward, an analysis is conducted to demonstrate the effectiveness of the repair techniques on the defined problem. The need for a retrofit method is first motivated by the lack of effective and easily implemented retrofit techniques for underwater structures when mix-mode fatigue cracks are present. Extended finite element (XFEM), with Paris’ Law and non-linear bond-slip behaviour of the adhesive, calibrates the crack propagation and strains surrounding the crack tip. The research then focuses on the discussion of the parametric analyses of large steel plate subjected to a combination of tension, shear and bending loads with and without CFRP repairs.
Cyclic Deformation and Low-Cycle Fatigue for 316LN Stainless Steel under Non-proportional Loading
Authors: Li Yajing , Ren Bin , Chen Xu
Published: December 2019

The effects of loading path and strain amplitude ratio on the cyclic behavior and fatigue life were investigated on a 316LN nuclear grade stainless steel employing a series of symmetrically strain-controlled fatigue tests at room temperature. The loading paths of Uniaxial, Torsional, Proportional, Rhombic, Rectangular, and Circular were employed with the constant equivalent strain amplitude of 0.5%. The strain amplitude ratio of 2.35, 1.73 and 1.27, defined by the ratio of shear strain amplitude to the axial strain amplitude, was realized by changing the shear strain amplitude under Proportional, Rhombic, Rectangular and Elliptical loading paths. As expected, the significant non-proportional additional hardening was observed. It’s interesting to note that the axial cyclic stress response varied with the strain amplitude ratio, and the law was different under different loading paths. The fatigue life of all the tests were evaluated by three critical plane criteria proposed by Smith-Watson-Topper (SWT), Fatemi-Socie (FS) and Chen-Xu-Huang (CXH). Results show that the SWT criterion significantly overestimated the fatigue life of non-proportional loading because the effect of shear damage was not considered. The CXH criterion for tensile-type failure yielded good prediction results except for two torsional data points. The FS criterion provided better predictions than other models.
Multiaxial fatigue behavior of 2618 aluminum alloy
Authors: Malek Benaïssa , Mabru Catherine , Chaussumier Michel
Published: December 2019

The purpose of the present research project is to study multiaxial fatigue behavior of 2618 alloy. The influence of mean stress on the fatigue behavior under tension and torsion is particularly investigated. Fatigue tests under combined tensile-torsion, in or out of phase, as well as combined tensile-torsion-internal pressure tests have also been conducted. Multiaxial fatigue results are analyzed according to Fatemi-Socie criterion to predict the fatigue life.
Cruciform specimens for the determination of crack growth behaviour in biaxial stress fields: calculation of K-factors
Authors: Wolf Carl H. , Burgold Andreas , Henkel Sebastian , Kuna Meinhard , Biermann Horst
Published: December 2019

The aim of this study is to propose a simplified calculation of the Mode I stress intensity factor K for the cruciform specimen design proposed by Brown and Miller. To calculate K, both cracks have to grow with a similar crack growth rate and the crack paths of the two single cracks with the length a should also be similar. The calculations are carried out on an aluminum specimen and a steel specimen. For all load cases and materials, the stresses resulting from the forces are first considered. It was found that the elastic constants E and ν have only a small influence of less than 3 %. In addition, the coupling between the forces of the load axes, which should be minimized by the slotted arms, is considered. Furthermore K-factors are calculated by FE for diﬀerent crack lengths. These K-values together with the transmission factor allow to find a K-factor formula for cruciform specimens, which is based on the prescribed forces. Finally, the results of the FE calculation of the exact straight crack paths were compared to experimentally determined crack paths.
An dissipated energy based analysis of fatigue crack propagation law
Authors: Vshivkov Aleksei , Iziumova Anastasiia , Yarullin Rustam , Shlyannikov Valery , Plekhov Oleg
Published: December 2019

The experimental study of heat flux evolution at the fatigue crack tip during biaxial loading was carry out in this work. The plane samples of stainless steel AISI 304 with thick of 3 mm were weakened by notch to initiate fatigue crack at the centre of samples. A contact heat flux sensor based on the Seebeck effect was used to monitor the dissipated thermal energy. During tests the samples were subjected to cyclic loading of 5 Hz with constant stress amplitude and different biaxial parameter. The experimental results confirm the previous conclusions of authors about two regime of energy dissipation at fatigue crack tip. The curve of the dissipated energy can be divided in two stages. In the second stage is characterized by classical linear relation between crack rate and energy dissipation. In the first stage the crack rate is proportional to the multiplication of the power of heat flux by crack length. The energy dissipation does not depend on the biaxial parameter during cyclic loading.
Generalization of the theory of critical distance to estimate lifetime of notched components in the medium-cycle fatigue regime
Authors: Borges Rafael , Araújo José , Silva Cosme , Dias Jéssica , Ferreira Jorge
Published: December 2019

This paper proposes a new and improved way to determine the dependency of the parameter that characterizes the process zone size ∫ with fatigue life Nf. Thus, unlike the classical approach, this approach has the advantage of allowing the construction of a ∫ versus Nf relationship, which is independent of the type of test used for calibration. In order to define the new relationship, a calibration strategy is presented considering the critical plane models based on the Fatemi-Socie and Smith-Watson-Topper. The accuracy of the method is verified by using data sets taken from the literature. A study on the effect of stress ratio (R) on the behaviour of the ∫ versus Nf relationship is presented and indicates that, although such relationship seems to depend on the R value used in the calibration, the life predictions obtained by these relationships are statistically similar.
The generalized criterion of multiaxial random fatigue based on conception proposed by prof. Macha
Authors: Łagoda Tadeusz , Kurek Marta , Łagoda Karolina
Published: December 2019

This criterion has been repeatedly verified, analyzed and special cases of this criterion reducing complex stress to equivalent uniaxial were taken into account. Since both normal and shear stress are vectors, we encounter the mathematical problem of adding these vectors, and the question arises how to understand the obtained equivalent stress, because two perpendicular vectors are added with weighting factors. Therefore, in this work it was proposed to adopt a system of complex numbers. Normal stress was defined as the real part and shear stress as imaginary part. As a result, on the basis of the defined complex number and basing on pure bending and pure torsion after transformations, the expression for equivalent stress was identical to the previously proposed criteria defined on the basis of the concept of prof. Macha.
Crack shielding in non-planar and frictional discontinuities under mixed-mode loading
Authors: Spagnoli Andrea , Carpinteri Andrea , Terzano Michele
Published: December 2019

In this paper, a two-dimensional model to describe the non-planar features of crack morphologies is presented. The model accounts for frictional tractions along the crack surfaces by considering an elastic-plastic-like constitutive interface law. Dilatancy effect due to crack roughness is described by the model, leading to a Mode I/II coupling between displacements and tractions along the crack surfaces. The non-linear solution of the rough and frictional crack under general remote scenarios is obtained using the Distributed Dislocation Technique (DDT). By considering a linear piecewise periodic profile of the interface crack, the influence of roughness and friction of interface cracks is examined in relation to both the resulting near-tip stress field and the fracture resistance under monotonic mixed-mode loading. The present model is able to quantify the increase of the fracture resistance due to roughnessand friction-induced crack tip shielding and to correlate it with a dimensionless crack size parameter.