bluuebunny/crossref_metadata_2025 huggingface dataset:
Alkyl chain length effects on double-deck assembly at a liquid/solid interface
Authors: Fang Yuan , Cibian Mihaela , Hanan Garry S. , Perepichka Dmitrii F. , De Feyter Steven , Cuccia Louis A. , Ivasenko Oleksandr
Published: July 2018

Controlled double-deck packing is an appealing means to expand upon conventional 2D self-assembly which is critical in crystal engineering, yet it is rare and poorly understood.
Well-dispersed Ni or MnO nanoparticles on mesoporous carbons: preparation via carbonization of bimetallic MOF-74s for highly reactive redox catalysts
Authors: Bhadra Biswa Nath , Jhung Sung Hwa
Published: July 2018

Ni or MnO-doped carbonaceous materials, prepared from pyrolysis of bimetal MOF-74s (composed of ZnMn or ZnNi), showed remarkable performances in a few redox reactions because of the well-dispersed MnO (and Ni) and high porosity with mesopores.
Dihydroindeno[1,2-b]pyrroles: new Al3+selective off–on chemosensors for bio-imaging in living HepG2 cells
Authors: Mal Kajal , Naskar Barnali , Mondal Animesh , Goswami Sanchita , Prodhan Chandraday , Chaudhuri Keya , Mukhopadhyay Chhanda
Published: July 2018

An approach for the expeditious synthesis of a new Al3+-selective turn-on dihydroindeno[1,2-b]pyrrole probe under environmentally benevolent conditions and its bio-imaging studies on HepG2 cell.
A novel synthesis ofN-hydroxy-3-aroylindoles and 3-aroylindoles
Authors: Ieronimo Gabriella , Palmisano Giovanni , Maspero Angelo , Marzorati Alessandro , Scapinello Luca , Masciocchi Norberto , Cravotto Giancarlo , Barge Alessandro , Simonetti Marco , Ameta Keshav Lalit , Nicholas Kenneth M. , Penoni Andrea
Published: July 2018

A straightforward indole synthesisviaannulation ofC-nitrosoaromatics with conjugated terminal alkynones was realised achieving 3-aroylindoles regioselectively.
Asymmetric synthesis of warfarin and its analogs catalyzed by C2-symmetric squaramide-based primary diamines
Authors: Kochetkov Sergei V. , Kucherenko Alexander S. , Zlotin Sergei G.
Published: July 2018

Novel C2-symmetric N,N′-bis(2-amino-1,2-diphenylethyl)squaramides with 1,2-di(pyridin-2-yl)ethane and 1,2-diphenylethane spacer groups were designed and applied as organocatalysts in asymmetric additions of 4-hydroxycoumarin and 4-hydroxy-6-methyl-2H-pyran-2-one to α,β-unsaturated ketones.
Molecularly imprinted artificial esterases with highly specific active sites and precisely installed catalytic groups
Authors: Hu Lan , Zhao Yan
Published: July 2018

A difficult challenge in synthetic enzymes is the creation of substrate-selective active sites with accurately positioned catalytic groups.
Widely used hardly known. An insight into electric and dynamic properties of formamidinium iodide
Authors: Mencel K. , Durlak P. , Rok M. , Jakubas R. , Baran J. , Medycki W. , Ciżman A. , Piecha-Bisiorek A.
Published: July 2018

The simple organic crystal formamidinium iodide (FAI) appeared to be a novel semiconducting material in a wide temperature range.
An efficient class of bis-NHC salts: applications in Pd-catalyzed reactions under mild reaction conditions
Authors: Chiu Chien-Cheng , Chiu Hui-Tzu , Lee Dong-Sheng , Lu Ta-Jung
Published: July 2018

This study describes an efficient class of bis-N-heterocyclic carbene (bis-NHC) salts that can be easily made from commercially available and inexpensive starting materials.
Synthesis and evaluation of new sterol derivatives as potential antitumor agents
Authors: Chen Xiang , Gan Yong Jun , Yu Yu , Zhang Yuan
Published: July 2018

The current optimization of tetrazanbigen (TNBG) on the C-ring provided a series of new sterol derivatives 2a–2n.
Direct N-heterocyclization of hydrazines to access styrylated pyrazoles: synthesis of 1,3,5-trisubstituted pyrazoles and dihydropyrazoles
Authors: Venkateswarlu Vunnam , Kour Jaspreet , Kumar K. A. Aravinda , Verma Praveen Kumar , Reddy G. Lakshma , Hussain Yaseen , Tabassum Aliya , Balgotra Shilpi , Gupta Sorav , Hudwekar Abhinandan D. , Vishwakarma Ram A. , Sawant Sanghapal D.
Published: July 2018

The synthesis of tri-substituted pyrazoles was achieved via direct N-heterocyclization of hydrazines with metal-acetylacetonate and -dibenzylideneacetonate without using any base or additives under microwave irradiation in a single step.
Magnetic response of chlorophyll self-assembly within hydrogel: a mechanistic approach towards enhanced photoharvesting
Authors: Mandal Pubali , Manna Jhimli S. , Das Debmallya , Maiti Ramaprasad , Mitra Manoj K. , Chakravorty Dipankar
Published: July 2018

Chlorophyll molecular-arrangement, geometry and coupling result in magnetic domain wall as well as edge effect. These facilitate topologically protected ultrafast energy migration, where back scattering of exciton is restricted.
Ultrafast interface charge transfer dynamics on P3HT/MWCNT nanocomposites probed by resonant Auger spectroscopy
Authors: Garcia-Basabe Yunier , Ceolin Denis , Zarbin Aldo J. G. , Roman Lucimara S. , Rocco Maria Luiza M.
Published: July 2018

The electronic coupling between P3HT polymer and multi-walled carbon nanotubes was elucidated using NEXAFS and core hole clock approaches.
Self-assembly of peptide amphiphiles by vapor pressure osmometry and dissipative particle dynamics
Authors: Seki Taiga , Arai Noriyoshi , Suh Donguk , Ozawa Taku , Shimada Tomoko , Yasuoka Kenji , Hotta Atsushi
Published: July 2018

Vapor pressure osmometry measurements and molecular simulation were carried out to investigate the self-assembly behavior of peptide amphiphiles. The results revealed that the head–water interaction plays an important role for their microstructure.
Characterization and electrochemical properties of iron-doped tetrahedral amorphous carbon (ta-C) thin films
Authors: Etula Jarkko , Wester Niklas , Sainio Sami , Laurila Tomi , Koskinen Jari
Published: July 2018

Surface iron levels as low as 0.4 at% (XPS) can considerably change the electrochemical properties of initially inert carbon surfaces.
Biomethanation of blast furnace gas using anaerobic granular sludgeviaaddition of hydrogen
Authors: Wang Ying , Yin Chenzhu , Liu Ye , Tan Mengjiao , Shimizu Kazuya , Lei Zhongfang , Zhang Zhenya , Sumi Ikuhiro , Yao Yasuko , Mogi Yasuhiro
Published: July 2018

The schematic diagram of mechanism for biomethanation of CO2and CO from blast furnace gas.
A comparative study on the photocatalytic degradation of organic dyes using hybridized 1T/2H, 1T/3R and 2H MoS2 nano-sheets
Authors: Saber Mohamed R. , Khabiri Gomaa , Maarouf Ahmed A. , Ulbricht Mathias , Khalil Ahmed S. G.
Published: July 2018

MoS2 is a very attractive material and has been well studied for potential applications in various areas.
Electric field-induced circulation and vacuolization regulate enzyme reactions in coacervate-based protocells
Authors: Yin Yudan , Chang Haojing , Jing Hairong , Zhang Zexin , Yan Dadong , Mann Stephen , Liang Dehai
Published: July 2018

The spatial distribution of the enzyme reaction is globalized throughout the protocell by tuning the coupling of the circulation and vacuolization processes.
Pt-like catalytic behavior of MoNi decorated CoMoO3cuboid arrays for the hydrogen evolution reaction
Authors: Wang Dewen , Han Ce , Xing Zhicai , Li Qun , Yang Xiurong
Published: July 2018

Owing to the unique structure and synergistic effect between MoNi and CoMoO3, the MoNi/CoMoO3/NF exhibits high hydrogen evolution activity which requires a low overpotential of only 18 mV to deliver a current density of 10 mA cm−2.
Dynamic reversible bonds enable external stress-free two-way shape memory effect of a polymer network and the interrelated intrinsic self-healability of wider crack and recyclability
Authors: Fan Long Fei , Rong Min Zhi , Zhang Ming Qiu , Chen Xu Dong
Published: July 2018

An external stress-free two-way shape memory effect, intrinsic self-healability and recyclability of crosslinked polyurethanes are enabled by dynamic reversible C–ON bonds.
Reduced graphene oxide nanoribbon immobilized gold nanoparticle based electrochemical DNA biosensor for the detection of Mycobacterium tuberculosis
Authors: Mogha Navin Kumar , Sahu Vikrant , Sharma Raj Kishore , Masram Dhanraj T.
Published: July 2018

A DNA based biosensor is reported with very high specificity to Mycobacterium tuberculosis and a detection limit much superior to those already reported in the literature.
Urinary metabolomics reveals novel interactions between metal exposure and amino acid metabolic stress during pregnancy
Authors: Wang Mu , Xia Wei , Liu Hongbin , Liu Fang , Li Han , Chang Huailong , Sun Jie , Liu Wenyu , Sun Xiaojie , Jiang Yangqian , Liu Hongxiu , Wu Chuansha , Pan Xinyun , Li Yuanyuan , Rang Weiqing , Lu Songfeng , Xu Shunqing
Published: July 2018

Pregnant women are a unique group undergoing profound structural modifications in uterus, breast, adipose tissue,etc.
Knockdown of long non-coding RNA linc00511 suppresses proliferation and promotes apoptosis of bladder cancer cells via suppressing Wnt/β-catenin signaling pathway
Authors: Li Jun , Li Yan , Meng Fandong , Fu Liye , Kong Chuize
Published: July 2018

More and more studies have shown that long non-coding RNAs (lncRNAs) play critical roles in various biological processes of bladder cancer, including proliferation, apoptosis, migration and cell cycle arrest. LncRNA long intergenic noncoding RNA 00511 (linc00511) is one of the lncRNAs highly expressed in bladder cancer tissues and cells. However, little is known about the roles and mechanisms of linc00511 in bladder cancer. Here, we demonstrated that linc00511 was highly expressed in bladder cancer tissues and cells. Linc00511 knockdown could cause the cell proliferation suppression and cell cycle arrest, which were mediated by p18, p21, CDK4, cyclin D1 and phosphorylation Rb. Suppressed linc00511 could induce the apoptosis in T24 and BIU87 cells via activating the caspase pathway. Down-regulation of linc00511 could also suppress the migration and invasion of T24 and BIU87 cells. In addition, we found that the expression of linc00511 was negatively correlated with that of miR-15a-3p in the clinical bladder cancer samples. Further mechanistic studies showed that linc00511 knockdown induced proliferation inhibition, and apoptosis increase might be regulated through suppressing the activities of Wnt/β-catenin signaling pathway. Thus, we revealed that knockdown of linc00511 suppressed the proliferation and promoted apoptosis of bladder cancer cells through suppressing the activities of Wnt/β-catenin signaling pathway. Moreover, we suggested that linc00511 could be a potential therapeutic target and novel biomarker in bladder cancer.
Effect of 3-nitropropionic acid inducing oxidative stress and apoptosis of granulosa cells in geese
Authors: Kang Bo , Wang Xinxing , Xu Qilin , Wu Yongsheng , Si Xiaohui , Jiang Dongmei
Published: July 2018

The mechanism of action by which oxidative stress induces granulosa cell apoptosis, which plays a vital role in initiating follicular atresia, is not well understood. In the present study, the effect of 3-nitropropionic acid (3-NPA) on oxidative stress and apoptosis in granulosa cells in geese was investigated. Our results showed that treatment with 3-NPA at 5.0 mmol/l for 24 h increased intracellular reactive oxygen species (ROS) production by 25.4% and decreased granulosa cell viability by 45.5% (P<0.05). Catalase and glutathione peroxidase gene expression levels in granulosa cells treated with 3-NPA were 1.32- and 0.49-fold compared with those of the control cells, respectively (P <0.05). A significant decrease in the expression level of B-cell lymphoma 2 (Bcl-2) protein and remarkable increases in the levels of Bax, p53 and cleaved-Caspase 3 proteins and the ratio of Bax/Bcl-2 expression in granulosa cells treated with 3-NPA were observed (P<0.05). Furthermore, a 38.43% increase in the percentage of early apoptotic cells was also observed in granulosa cells treated with 3-NPA (P<0.05). Moreover, the expression levels of NF-κB, Nrf2, Fhc, Hspa2 and Ho-1 in granulosa cells treated with 3-NPA were elevated 4.36-, 1.63-, 3.62-, 27.54- and 10.48-fold compared with those of the control cells (P<0.05), respectively. In conclusion, the present study demonstrates that treatment with 3-NPA induces ROS production and apoptosis and inhibits the viability of granulosa cells in geese. Furthermore, 3-NPA triggers increases in the expression of cleaved-Caspase 3 protein and the ratio of Bax/Bcl-2 expression, and induces the early apoptosis of granulosa cells.
LncRNA SNHG3 enhances the malignant progress of glioma through silencing KLF2 and p21
Authors: Fei Fan , He Yongsheng , He Sen , He Zhongze , Wang Youyu , Wu Gang , Li Mengni
Published: July 2018

As a newly discovered long non-coding RNA, small nucleolar RNA host gene 3 (SHNG3) has been reported to be dysregulated in certain cancers. Nevertheless, the details about clinical values and biological effects of SNHG3 on glioma are still covered. In this paper, we determined the expression level of SNHG3 in glioma tissues and cells and evaluated the effect of SNHG3 expression on the prognosis of glioma patients. The functional assays were applied to define the effects of SNHG3 on the biological behaviors in glioma including cell proliferation, cell cycle, and apoptosis. It was revealed that SNHG3 was much more enriched in glioma tissues and cell lines than in normal ones. Furthermore, gain- or loss-of-function experiments indicated that the up-regulation of SNHG3 promoted cell proliferation, accelerate cell cycle progress, and repressed cell apoptosis. The mechanistic assays disclosed that SNHG3 facilitated the malignant progression of glioma through epigenetically repressing KLF2 and p21 via recruiting enhancer of zeste homolog 2 to the promoter of KLF2 and p21. Generally, it was exposed that SNHG3 might function as an oncogene in glioma and could be explored as a potential prognostic biomarker and therapeutic target for glioma.
The Solar Twin Planet Search
Authors: Lorenzo-Oliveira Diego , Freitas Fabrício C. , Meléndez Jorge , Bedell Megan , Ramírez Iván , Bean Jacob L. , Asplund Martin , Spina Lorenzo , Dreizler Stefan , Alves-Brito Alan , Casagrande Luca
Published: July 2018

Context. It is well known that the magnetic activity of solar-type stars decreases with age, but it is widely debated in the literature whether there is a smooth decline or if there is an early sharp drop until 1–2 Gyr that is followed by a relatively inactive constant phase.

Aims. We revisited the activity-age relation using time-series observations of a large sample of solar twins whose precise isochronal ages and other important physical parameters have been determined.

Methods. We measured the Ca II H and K activity indices using ≈9000 HARPS spectra of 82 solar twins. In addition, the average solar activity was calculated through asteroids and Moon reflection spectra using the same instrumentation. Thus, we transformed our activity indices into the S Mount Wilson scale (SMW), recalibrated the Mount Wilson absolute flux and photospheric correction equations as a function of Teff, and then computed an improved bolometric flux normalized activity index log R′HK (Teff) for the entire sample.

Results. New relations between activity and the age of solar twins were derived by assessing the chromospheric age-dating limits using log R′HK (Teff). We measured an average solar activity of SMW = 0.1712 ± 0.0017 during solar magnetic cycles 23–24 covered by HARPS observations, and we also inferred an average of SMW = 0.1694 ± 0.0025 for cycles 10–24, anchored on a sunspot number correlation of S index versus. We also found a simple relation between the average and the dispersion of the activity levels of solar twins. This enabled us to predict the stellar variability effects on the age-activity diagram, and consequently, to estimate the chromospheric age uncertainties that are due to the same phenomena. The age-activity relation is still statistically significant up to ages around 6–7 Gyr, in agreement with previous works using open clusters and field stars with precise ages.

Conclusions. Our research confirms that Ca II H & K lines remain a useful chromospheric evolution tracer until stars reach ages of at least 6–7 Gyr. We found evidence that for the most homogenous set of old stars, the chromospheric activity indices seem to continue to decrease after the solar age toward the end of the main sequence. Our results indicate that a significant part of the scatter observed in the age-activity relation of solar twins can be attributed to stellar cycle modulations effects. The Sun seems to have a normal activity level and variability for its age.
Oxygen and helium in stripped-envelope supernovae
Authors: Fremling C. , Sollerman J. , Kasliwal M. M. , Kulkarni S. R. , Barbarino C. , Ergon M. , Karamehmetoglu E. , Taddia F. , Arcavi I. , Cenko S. B. , Clubb K. , De Cia A. , Duggan G. , Filippenko A. V. , Gal-Yam A. , Graham M. L. , Horesh A. , Hosseinzadeh G. , Howell D. A. , Kuesters D. , Lunnan R. , Matheson T. , Nugent P. E. , Perley D. A. , Quimby R. M. , Saunders C.
Published: July 2018

We present an analysis of 507 spectra of 173 stripped-envelope (SE) supernovae (SNe) discovered by the untargeted Palomar Transient Factory (PTF) and intermediate PTF (iPTF) surveys. Our sample contains 55 Type IIb SNe (SNe IIb), 45 Type Ib SNe (SNe Ib), 56 Type Ic SNe (SNe Ic), and 17 Type Ib/c SNe (SNe Ib/c). We have compared the SE SN subtypes via measurements of the pseudo-equivalent widths (pEWs) and velocities of the He I λλ5876, 7065 and O I λ7774 absorption lines. Consistent with previous work, we find that SNe Ic show higher pEWs and velocities in O I λ7774 compared to SNe IIb and Ib. The pEWs of the He I λλ5876, 7065 lines are similar in SNe Ib and IIb after maximum light. The He I λλ5876, 7065 velocities at maximum light are higher in SNe Ib compared to SNe IIb. We identify an anticorrelation between the He I λ7065 pEW and O I λ7774 velocity among SNe IIb and Ib. This can be interpreted as a continuum in the amount of He present at the time of explosion. It has been suggested that SNe Ib and Ic have similar amounts of He, and that lower mixing could be responsible for hiding He in SNe Ic. However, our data contradict this mixing hypothesis. The observed difference in the expansion rate of the ejecta around maximum light of SNe Ic (Vm = √2Ek/Mej ≈ 15 000 km s−1) and SNe Ib (Vm ≈ 9000 km s−1) would imply an average He mass difference of ∼1.4 M⊙, if the other explosion parameters are assumed to be unchanged between the SE SN subtypes. We conclude that SNe Ic do not hide He but lose He due to envelope stripping.
A collection of model stellar spectra for spectral types B to early-M
Authors: Allende Prieto C. , Koesterke L. , Hubeny I. , Bautista M. A. , Barklem P. S. , Nahar S. N.
Published: July 2018

Context. Models of stellar spectra are necessary for interpreting light from individual stars, planets, integrated stellar populations, nebulae, and the interstellar medium.

Aims. We provide a comprehensive and homogeneous collection of synthetic spectra for a wide range of atmospheric parameters and chemical compositions.

Methods. We compile atomic and molecular data from the literature. We adopt the largest and most recent set of ATLAS9 model atmospheres, and use the radiative code ASSϵT.

Results. The resulting collection of spectra is made publicly available at medium and high-resolution (R ≡ λ/δλ = 10 000, 100 000 and 300 000) spectral grids, which include variations in effective temperature between 3500 K and 30 000 K, surface gravity (0 ≤ log g ≤ 5), and metallicity (−5 ≤ [Fe/H] ≤ +0:5), spanning the wavelength interval 120–6500 nm. A second set of denser grids with additional dimensions, [α/Fe] and micro-turbulence, are also provided (covering 200–2500 nm). We compare models with observations for a few representative cases.
The Gaia-ESO Survey: The N/O abundance ratio in the Milky Way
Authors: Magrini L. , Vincenzo F. , Randich S. , Pancino E. , Casali G. , Tautvaišienė G. , Drazdauskas A. , Mikolaitis Š. , Minkevičiūtė R. , Stonkutė E. , Chorniy Y. , Bagdonas V. , Kordopatis G. , Friel E. , Roccatagliata V. , Jiménez-Esteban F. M. , Gilmore G. , Vallenari A. , Bensby T. , Bragaglia A. , Korn A. J. , Lanzafame A. C. , Smiljanic R. , Bayo A. , Casey A. R. , Costado M. T. , Franciosini E. , Hourihane A. , Jofré P. , Lewis J. , Monaco L. , Morbidelli L. , Sacco G. , Worley C.
Published: July 2018

Context. The abundance ratio N/O is a useful tool to study the interplay of galactic processes, for example star formation efficiency, timescale of infall, and outflow loading factor.

Aims. We aim to trace log(N/O) versus [Fe/H] in the Milky Way and to compare this ratio with a set of chemical evolution models to understand the role of infall, outflow, and star formation efficiency in the building up of the Galactic disc.

Methods. We used the abundances from IDR2-3, IDR4, IDR5 data releases of the Gaia-ESO Survey both for Galactic field and open cluster stars. We determined membership and average composition of open clusters and we separated thin and thick disc field stars. We considered the effect of mixing in the abundance of N in giant stars. We computed a grid of chemical evolution models, suited to reproduce the main features of our Galaxy, exploring the effects of the star formation efficiency, infall timescale, and differential outflow.

Results. With our samples, we map the metallicity range −0.6 ≤ [Fe/H] ≤ 0.3 with a corresponding −1.2 ≤ log(N/O) ≤ −0.2, where the secondary production of N dominates. Thanks to the wide range of Galactocentric distances covered by our samples, we can distinguish the behaviour of log(N/O) in different parts of the Galaxy.

Conclusions. Our spatially resolved results allow us to distinguish differences in the evolution of N/O with Galactocentric radius. Comparing the data with our models, we can characterise the radial regions of our Galaxy. A shorter infall timescale is needed in the inner regions, while the outer regions need a longer infall timescale, coupled with a higher star formation efficiency. We compare our results with nebular abundances obtained in MaNGA galaxies, finding in our Galaxy a much wider range of log(N/O) than in integrated observations of external galaxies of similar stellar mass, but similar to the ranges found in studies of individual H II regions.
The mass-metallicity relation of high-z type-2 active galactic nuclei
Authors: Matsuoka K. , Nagao T. , Marconi A. , Maiolino R. , Mannucci F. , Cresci G. , Terao K. , Ikeda H.
Published: July 2018

The mass-metallicity relation (MZR) of type-2 active galactic nuclei (AGNs) at 1.2 < z < 4.0 is investigated by using high-z radio galaxies (HzRGs) and X-ray selected radio-quiet AGNs. We combine new rest-frame ultraviolet (UV) spectra of two radio-quiet type-2 AGNs obtained with FOCAS on the Subaru Telescope with existing rest-frame UV emission lines, i.e., C IVλ1549, He IIλ1640, and C IIIλ1909, of a sample of 16 HzRGs and 6 additional X-ray selected type-2 AGNs, whose host stellar masses have been estimated in literature. We divided our sample in three stellar mass bins and calculated averaged emission-line flux ratios of C IVλ1549/He IIλ1640 and C IIIλ1909/C IVλ1549. Comparing observed emission-line flux ratios with photoionization model predictions, we estimated narrow line region (NLR) metallicities for each mass bin. We found that there is a positive correlation between NLR metallicities and stellar masses of type-2 AGNs at z ~ 3. This is the first indication that AGN metallicities are related to their hosts, i.e., stellar mass. Since NLR metallicities and stellar masses follow a similar relation as the MZR in star-forming galaxies at similar redshifts, our results indicate that NLR metallicities are related to those of the host galaxies. This study highlights the importance of considering lower-mass X-ray selected AGNs in addition to radio galaxies to explore the metallicity properties of NLRs at high redshift.
Simulating non-axisymmetric flows in disk galaxies
Authors: Randriamampandry T. H. , Deg N. , Carignan C. , Widrow L. M.
Published: July 2018

Context. We present a two-step method to simulate and study non-circular motions in strongly barred galaxies. The first step is to constrain the initial parameters using a Bayesian analysis of each galaxy’s azimuthally averaged rotation curve, the 3.6 μm surface brightness, and the gas surface density. The second step is to generate equilibrium models using the GalactICS code and evolve them via GADGET-2.

Aims. The bar strengths and mock velocity maps of the resulting snapshots are compared to observations in order to determine the best representation of the galaxy.

Methods. We apply our method to the unbarred galaxy NGC 3621 and the barred galaxies NGC 1300 and NGC 1530. NGC 3621 provides a validation of our method of generating initial conditions. NGC 1530 has an intermediate bar orientation that allows for a comparison to DiskFit. Finally NGC 1300 has a bar oriented parallel to the galaxy’s major axis, where other algorithms tend to fail.

Results. Our models for NGC 3621 and NGC 1530 are comparable to those obtained using commonly available algorithms. Moreover, we produce one of the first mass distribution models for NGC 1300.
Analysis of chip formation and cutting forces in end milling AISI D2 tool steel with different cutting tool geometries
Authors: Beşliu Irina , Amarandei Dumitru , Cerlincă Delia
Published: July 2018

The purpose of this study was to investigate and establish the correlations between milling tool geometry, cutting conditions, as input factors and the cutting forces variations and chips formation, as output factors when end milling of AISI D2 tool steel. The experiments were carried out using a Taguchi design array. The chip shape and microstructure and cutting force components were analyzed. The results of the study show that the cutting tool geometry has a great influence over segmented chip formation mechanism and cutting force levels.
The neural networks used in FDM printing study
Authors: Munteanu Adriana , Chitariu Dragos-Florin
Published: July 2018

Neural networks have aroused a lively interest since 1943 when Warren McCulloch and Walter Pitts proposed a neural network model (a single layer model), that has remained fundamentally structural even today for most neural networks. Problem solving and implicit the study of a system's operating model such as 3D printing involves the association between input data, hypotheses and output data, and neural networks provide the ability to form their own model of solving. The main difference between neural networks and other information processing systems is the ability to learn from interacting with the environment and so improving performance. A correct representation of information, allowing interpretation, prediction, and response to an external stimulus, can allow the network to build a model of the considered process, in the paper case fused deposition modelling (FDM) process.
Designing of an innovative extrusion system for metallic parts made by desktop 3D printing method
Authors: Pacurar Razvan , Pacurar Ancuta , Pop Serban
Published: July 2018

Desktop 3D Printing for metallic parts is a new direction and represents one of the latest trends within the Additive Manufacturing domain, being given and defined mainly by the requirements of the industrial companies in terms of materials and products that needs to be rapidly delivered on the market. The article presents an innovative solution that was developed at the Technical University of Cluj-Napoca in this domain, for the Rapid Product Development of Parts made by metal extrusion.
The analysis of the parameters for deep drawing of cylindrical parts
Authors: Chiorescu Dan , Chiorescu Esmeralda , Olaru Sergiu
Published: July 2018

Deep drawing is a very important metal forming process. Thin steel sheet is important material for manufacture of numerous products with deep drawing and stamping. Cold working provides also the possibility of making parts of various shapes, from the simplest to those with a high degree of complexity whose execution through other methods is uneconomical, difficult and sometimes even impossible. In this paper it is analyzed both experimentally and with the help of the finite element, the behavior of the blank during the cylindrical cup deep drawing process, using the ANSYS software program and the finite element method. A comparison is realized between the experimental and the analytical results, elaborating a representative set of problems that analyze the variation of the die punch clearance, movement of the punch and with or without lubrication. The results of the research are useful in developing a sensible design of experiments.
Experimental study on reverse engineering in case of composite materials cut by water jet cutting
Authors: Popan Ioan Alexandru , Balc Nicolae , Popan Alina , Carean Alexandru
Published: July 2018

The main objective of the paper consists in remanufacturing of a part, through Abrasive Water Jet Cutting, using a method of reverse engineering based on 3D scanning. The characteristics of this process, the equipment and the main applications are presented. The research starts with manufacturing of a master model made by CFRP. This master model is a complex part cut by abrasive water jet cutting. In scanning process was used the 3D Scanner Artec Space Spider and the point cloud was processed using Artec Studio 11 software. By using this new 3D model was manufactured a new part, with the same setup. The quality characteristics (accuracy and surface quality) of this part was compared with the master model. The paper presents the advantages and disadvantages of this reverse engineering method applied on abrasive water jet cutting process.
The effects of quality finishing surface on sealing and gluing
Authors: Petrisor Alexandra , Nagit Gheorghe , Tabacaru Lucian
Published: July 2018

In the assembly processes of mechanical parts from semifinished parts and finished parts there are different levels of roughness and different types of defects. This is mainly affecting the final surface of the finished parts. The founded defects can be from different categories like: irregular shape and surface, deformed edge, processing defects, little particles that combined with high pressures can make the parts crack. In the end this affects the sealing and the tightness of the assembled goods. After assembly it can also influence the performance of the resistance, the cycle life of the parts, the dullness and also the precision of final power packs. In this paper it is going to be established what are the parameters and the conditions for a stable sealing process that could survive to different environmental pressures. This results are presented after observation of various mechanical assemblies and their guidelines in which were determined the circumstance for a proper sealing. The main functions of the adhesion are the fixation and the sealing with a mechanical connection. In order to perform on maximum capacity this connection must be stable and strong and capable to hold to every impediment and test submitted. The following application used for gluing and sealing of electronic and mechanical components can be put it on single parts or in assembled parts and also for complex circuits, having a various applicability and utility in automotive industry.
3D laser scanning and digital restoration of an archaeological find
Authors: Fragkos Stergios , Tzimtzimis Emanuel , Tzetzis Dimitrios , Dodun Oana , Kyratsis Panagiotis
Published: July 2018

The current paper demonstrates the digital recreation and 3D printing of a missing fragment of an ancient ceramic pottery following digitization using a three dimensional laser scanning. The resulting pointcloud of the laser scans was treated with a series of advanced software for the creation of surfaces and ultimately for a digital model. An analytical methodology is presented revealing the step by step approach, which is an innovative way of recreating a missing fragment. Such approach aims to demonstrate the level of contribution that the ever evolving computer based technologies and 3D printing could bring to cultural heritage. The reverse engineering method presented for the reconstruction of a ceramic pottery, which is a part of the larger field of digital archaeology, is believed to benefit a variety of interested parties including 3D CAD users and designers, archaeologists and museum curators.
Molecular dynamics simulation of multi-pass nano-grinding process
Authors: Karkalos Nikolaos E. , Markopoulos Angelos P.
Published: July 2018

Grinding involves the use of a large number of micrometric abrasive grains in order to remove material from workpiece surface efficiently and finally render a high quality surface. More specifically, grinding in the nano-metric level serves for attaining nano-level surface quality by removing several layers of atoms from the workpiece surface. The abrasive grains act as individual cutting tools, performing primarily material removal but also induce alterations in the subsurface regions. In order to study the nano-grinding process, Molecular Dynamics (MD) method is particularly capable to provide comprehensive observations of the process and its outcome. In this study, MD simulations of multi-pass grinding for copper substrates, using two abrasive grains, are performed. After the simulations are carried out, results concerning grinding forces and temperatures are presented and discussed.
Enhancing the properties of some inverse opal metamaterials by the stopband control
Authors: Ionescu Daniela , Macovei Irina
Published: July 2018

The inverse opal structures present very good mechanical and optical properties, like high mechanical strength and Young modulus, important photoluminescence and stimulated Brillouin scattering. Enhancement of the optical properties of the metamaterials based on different types of inverse opal can be obtained by controlling the stopband of the 3D periodic structure. SiO2, TiO2 and CeO2 photonic crystals with inverse opal structures have been studied, presenting voids of 100 – 280 nm. The stopband dependence on the physical and geometrical parameters of the matrix has been analyzed (ions nature, voids diameter, photoelastic constant). The study was performed by structural simulation methods, using the HFSS program. The test configuration was set for the visible light domain. The effective refraction index n and the stimulated Brillouin scattering coefficient gP have been determined and represented on parametrical graphs. Results were compared with the theoretic calculated values. By varying different structural parameters and the stopband control, superior values of the optical parameters have been obtained, in comparison with the data given in literature. We report an increasing of the photoluminescence with about 7%, respectively and enhancement of the stimulated Brillouin scattering coefficient of 11 % when parameters are correlated.
Applying of a design methodology for a new mobility product
Authors: Gheorghiţă Vlad , Gheorghiţă Cătălin
Published: July 2018

Product innovation involves an understanding of technology through the introduction of a product that is new or has significantly improved characteristics and intended uses with the purpose of upgrading or even changing, in this case, the mobility landscape. Although product development is creative in upgrading components, the implementation requires a systematic approach to guide the processes that must be taken into account and applied to achieve the implementation of a new product to market. To be successful it is important that the needs, preferences and limitations, be taken into consideration. In this paper, an optimized methodology for developing a new product is proposed starting from the existing ones. By investigating the current concepts of solutions to improve the ability to move physically, it is attempted to propose a typology to address the mobility problem. On a basic manual wheelchair, a system will be attached to ensure overcoming the obstacles and to guarantee the ability to negociate effectively.
Numeric analysis of airflow around the body of the Silesian Greenpower vehicle
Authors: Baier Andrzej , Grabowski Łukasz , Stebel Łukasz , Komander Mateusz , Konopka Przemysław , Kołodziej Alicja , Żur Paweł
Published: July 2018

Numerical analysis of drag values of an electric race car's body. Silesian Greenpower is a student organization specializing in electric race car design. One of the most important issues during the design is reducing the vehicle drag to minimum and is done, mainly, by designing a streamline car body. The aim of this work was to design two electric cars bodies with different shape in Siemens NX CAD software, next a finite elements mesh was created and implemented into the ANSYS Workbench 16.1 software. Afterwards an aerodynamic analysis was carried out, using the finite element method (FEM). Simulations and calculations have been performed in ANSYS Fluent: CFD Simulation software. Computer simulation allowed to visualize the distribution of air pressure on and around car, the air velocity distribution around the car and aerodynamics streamline trajectory. The results of analysis were used to determine the drag values of electric car and determine points of the highest drag. In conclusion car body representing lower drag was appointed. The work includes theoretical introduction, containing information about finite element method, ANSYS and Siemens NX software and also basic aerodynamics laws.
Research regarding the action of the aerodynamic forces on a classical passenger train
Authors: Arsene Sorin
Published: July 2018

Technological development of the past decades has made it possible in the case of railway vehicles to continually improve dynamic and traction performance. This has determined, in the case of the conventional system (the railway vehicle on rails) a steady increase in travel speeds, reaching the record value 578 km/h. The current trend, in the case of the conventional classical trains composed from the locomotives and wagons are the maximum travel speeds to be at values of 200 - 250km/h. In the case of Electric multiple unit (EMU), the maximum speeds allowed in the current traffic are between 300 - 450 km/h. These increases in travel speeds would not have been possible without first studying in more detail the aerodynamic phenomena that act on the vehicles during their travel. This paper intends to analyses how the aerodynamic forces acts in the case of a classic passenger train formed up of a motor vehicles (locomotive) and three towed vehicles. For the determination of aerodynamic force values, an air flow simulation program will be used in case the train moves under normal atmospheric conditions.
The choice of concrete mixers for the concrete preparation
Authors: Kaitukov Batraz , Stepanov Mihail , Kapyrin Pavel
Published: July 2018

The production of commodity concretes is a large segment of the construction industry and a testing base for concrete mixers. The choice of high-reliable concrete mixers for high-quality production of various brands of concrete is topical. When choosing concrete mixers, the most important is condition for improving the quality of mixing. Solving this problem, the analysis of various parameters and structural designs of concrete mixers is carried out. Dependencies are established that show the properties of concrete of various brands with their composition and technical characteristics of concrete mixers. Variants of rational selection of concrete mixers that provide high uniformity of concretes and a combination of the components of the mixture are proposed. The capacities of various concrete mixers for the preparation of commodity concrete are determined and the optimum rotational speeds of the working elements of concrete mixers are determined. Reasonable speeds of movement of working elements are revealed and dependences of the Reynolds number on frequency of rotation of a drum between capacity and diameter of a drum of a concrete mixer are established. This method of selecting rational concrete mixers allows reducing operating costs and improving the quality of concrete.
Technological machines, construction resources, efficiency and safety
Authors: Sevryugina Nadegda , Kapyrin Pavel
Published: July 2018

Understanding the direct relationship of the person, his activities Wednesday habitats requires not only new methodological approaches to research, but, first and foremost, clarify the existing scientific theories, their coherence with the development the environment Wednesday. A model of modernization of transport and technological machines as a factor in the realization of tasks of improving their effectiveness, safety and environmental performance. The main focus in addressing modifications of technological machines in use is considered lowering their material intensity, by adopting a more rugged and durable in endurance and wear materials. Modified methodology of estimation of residual resource of technical facilities by implementing technology upgrades for further reliable and safe operation. In the method a key factor is the effective and safe operation. Developed a calculation model of optimization of the resource in terms of assessing risk of system failure due to functional aging; optimization model of the resource, frequency of maintenance and wear limit of units in terms of assessing risk of occurrence of a system failure affecting safety. The solution of the question of resource upgrading to provide manufacturers, as an additional stage of the life cycle of construction machinery and means of complex mechanization.
Taking decisions in the diagnostic intelligent systems on the basis information from an artificial neural network
Authors: Duer Stanisław , Scaticailov Serghei , Paś Jacek , Duer Radosław , Bernatowicz Dariusz
Published: July 2018

This paper presents a method to control an operation process of a complex technical object, with the use of trivalent diagnostic information. Also, a general diagram of the complex technical object was presented, and its internal structure was described. A diagnostic analysis was conducted, as a result of which sets of the functional elements of the object and its diagnostic signals were determined. Also, the methodology of the diagnostic examination of the technical system was presented. The result was a functional and diagnostic model, which constituted the basis for initial diagnostic information, which is provided by the sets of information concerning the elements of the basic modules and their output signals. The theoretical results obtained in the present study were verified in practice on the example of a complex and reparable technical object. It belongs to the group of technical equipment for which a short time of shutdowns is required (an ineffective use of the object).
SMEs creativity and smart regional development
Authors: Pirnau Claudiu , Ghiculescu Daniel , Marinescu Niculae Ion
Published: July 2018

The paper presents new methods of smart regional development, starting from a question and one answer: How do we go about building our local smart ecosystem? Make one step at a time. This step is achieved through a number of seven elements: the SMEs network, the relations between universities and the labour market, the efficient using of transport infrastructure, the interactions specific to the various forms of capital with accent on intangible assets, smart relocation, online and offline interactions in smart communities, the used of young staff as a source of creativity and innovation, oriented to smart specialization, leading to sustainable competitive advantage.
The liquid CO2 disposal in sea pits near Greece
Authors: Mândrea Lucian , Bădescu Viorel , Militaru Gheorghe
Published: July 2018

As long as human activity requires much energy, a large amount of CO2 is produced. The World Meteorological Organization announced that in 2016 the CO2 concentrations in atmosphere reached a new record. This is the highest growth in the last 30 years, based on measurements performed in 51 countries. The growth concentration is with 50% higher than the mean level of the last 10 years. The level of the CO2 in the atmosphere is 100 times higher than at the end of the glacial era. This can cause unexpected changes of the climate and also severe destructions of the economic system. Even if researchers believe that the raised level of CO2 is not responsible for the rise of the temperature on the globe, we agree that the initiative to diminish the CO2 level in the atmosphere is a useful one. We propose the possibility to deposit an amount of liquid CO2 in a deep pit near Greece as an example of what can be done to protect the environment. We solved at the beginning the problem using an integral calculus to estimate the liquid CO2 flow rate. Then we calculated the time in which a pit can collect what is sent at the bottom of the Mediterranean Sea.
Factors affecting configuration plans in product development
Authors: Sadeh Arik , Gecht Shlomi , Feniser Cristina
Published: July 2018

Configuration Management( CM )is an engineering methodology through which it is possible to manage and control all the stages that the product undergoes throughout its life cycle. The applied methodology is relevant to many different engineering disciplines and various products. CM is part of system engineering and it includes many management aspects. This study deals with factors that make up the CM configuration management methodology of all its components. The background and motivation for conducting this research was raised from inspection of outcomes from many development processes of new products, or improvement and changes in design of existing products, in hi-tech organizations in Israel. It was found that in some organizations the issue of configuration management is often not large or not large enough, and accordingly, too little resources are allocated to the subject. The study refers to the configuration management schema according to CMII (Configuration Management version 2). The study examines the level of configuration management with respect to the effects of the following variables and their level in the organization: (i) Requirements Management), (ii) Change Management, (iii) Release Management), (iv) Data Management), (v) Report Management, (vi) Document Management, and (vii) Software Tools Management. The study includes a comprehensive survey of 104 system engineers, managers and project managers related to the field of configuration management processes. The results of the study indicate the relative importance of each factor involved in configuration management. They are very useful for organizations whose main focus is research and development and new product development
Agile management in the context of Russian industrial sector
Authors: Gromova Elizaveta A.
Published: July 2018

The Fourth Industrial Revolution is a new era in the development of mankind, which makes changes in the economic sphere. Agile approach is a suitable management model that can counteract to such issues as uncertainty and rapid changes in business environment. The goal of the study is to analyze this model and to relate it to the Russian industrial sector. Theoretical and practical aspects of the agile concept are presented. The conclusion about the effectiveness of the agile management that meets the necessary modern requirements, for the Russian industry development is drawn.
Considerations on the derailment causes over the years on the Romanian railway network
Authors: Nicolescu Mircea
Published: July 2018

This paper has analysed a series of railway accidents produced by derailment in two different time periods: 1938-1945 and 2010-2011, in attempting to compare direct causes typologies. The comparison serves as purpose to establish the way in which technological development produced several changes and the conclusions can be surprising. In spite of the technical evolutions in the railroads industry during 70 years, a lot of the causes remain the same.