bluuebunny/crossref_metadata_2025 huggingface dataset:
Rolling Bearing Fault Classification Based on Stacked Denoising Auto Encoders
Authors: Jia Liangliang , Du Xianjun
Published: May 2021

Aiming at the characteristics of large capacity and diversity of rolling bearing fault data, an intelligent rolling bearing fault diagnosis method based on stacked denoising auto encoders was proposed. Firstly, Principal Component Analysis was used to reduce the dimension of the original data, and the redundant information is deleted. Then, three de-noising auto-encoders are created to train the bearing data. Then, a stack de-noising auto-encoder with three hidden layers is stacked with the trained DAE for reverse optimization. Finally, the features are input into soft-max classifier to realize rolling bearing fault diagnosis. The experimental results show that SDAE network can extract fault features effectively, and it is better than back propagation neural network in generalization and fault classification accuracy.
Fourier series for synthesis and analysis of periodic signals
Authors: Hao Yunman
Published: May 2021

This report mainly explores three major parts, namely, periodic discrete-time signals, generation of periodic Fourier signals and analysis of quasi-periodic Fourier signals. We use Matlab to analyze the signal and generate Excel spreadsheet. The waveforms of different frequencies are drawn by Matlab, and the waveforms are analyzed. In addition, the formula for synthesizing periodic signals is simplified and demonstrated here.
Multi-Objective Optimal Allocation Of DG-EV Charging Station Considering Space-Time Characteristics Model
Authors: Chen Xianda , Gao Chao , Chen Xingyu , Lin Yufeng , Li Jiyu , Yang Yihao
Published: May 2021

With the promotion and development of new energy in the country, Distributed Generation (DG) and electric vehicle (EV) are welcoming development opportunities. The paper proposes a DG-EV charging station that considers space-time characteristics. Multi-objective coordination optimization configuration method, by extracting the road network topology in the city, monitoring the road network traffic, using the traffic planning software TransCAD to carry out the OD matrix back-pull, establishing the travel probability matrix to describe the user travel characteristics, considering the timing characteristics of EV, DG and conventional load, taking into account the grid side and the user side, and establishing a multi-objective joint planning model for the DG-EV charging station with the sub-goal of comprehensive benefit, system load fluctuation and charging time-consuming cost. Finally, the simulation analysis of the IEEE-33 node distribution network and the main road in a certain urban area is carried out to verify the validity and feasibility of the model.
Three-dimensional modeling of pendulum waves propagation under dynamic loading of underground excavation surface
Authors: Aleksandrova NI
Published: May 2021

The propagation of surface pendulum waves under nonstationary loading on the free surface of a cavity located in a block half-space is studied numerically. A mathematical model of transient viscoelastic deformation of the block medium is proposed. This model is based on the idea that dynamic behavior of the block medium can be approximately described as the movement of rigid blocks due to the compliance of interlayers between them. To describe the viscoelastic behavior of the interlayers, an internal friction model is used with the merit factor of the material as the determining parameter. The medium is modeled by a three-dimensional lattice of masses connected by elastic springs and viscous dampers in axial and diagonal directions. The influence of the merit factor and the cavity depth on the amplitudes of block velocities on the surface of the half-space is investigated for the longitudinal and Rayleigh waves.
Study of regularities of changes in stress-strain state of coal–rock mass in fractured zones
Authors: Demin VF , Nemova NA
Published: May 2021

The regularities of changes in the stress-strain state of coal in rock mass depending on the main mining geological and engineering factors are identified. Using these factors, it is possible to find the optimal support parameters in specific conditions to increase the stability of preparatory mine workings. The degree of influence of mining and engineering conditions of exploitation on displacements in marginal rocks with various types of support in excavation workings is investigated.
Ultimate pressure determination in hydraulic fracturing of boreholes for different rock failure criteria
Authors: Kovrizhnykh AM , Kurlenya MV
Published: May 2021

The problem on elastoplastic deformation and rock failure around boreholes under the action of internal pressure is considered. The stress state in the intact rock mass is assumed to be hydrostatic. The hydraulic fracturing pressure is conventionally determined by the maximum normal stress criterion. However, the experimental studies described in scientific articles show that this criterion is not consistent with the results obtained in the course of laboratory tests on failure of cylindrical and spherical cavities made in rock samples. It has been known that test results on complex loading for solid samples of various materials are not confirmed by the theory of maximum normal stress both in terms of ultimate load value and direction of failure surface propagation. In this case, for the complex stress state of rocks, it is proposed to determine the ultimate pressure by the experimentally substantiated fracture criteria which are in good agreement with the results of laboratory tests on hydraulic fracturing of boreholes.
Effect of the proppant on fracture compressibility in coal seam
Authors: Shilova TV
Published: May 2021

The paper discusses enhancement of gas drainage well productivity in coal seams using the hydraulic fracturing technology. Filling of a fracture with proppant provides a long-term increase in the gas drainage well performance. The results of the laboratory experiments to determine coal permeability under various stress conditions show that proppants significantly reduce fracture compressibility and the propped fracture becomes less sensitive to stress variations.
Determination of shapes and sizes of radial cracks formed by blasthole charges and hydraulic fracturing in a layered rock mass
Authors: Sher EN
Published: May 2021

The features are investigated and a design diagram is developed for radial cracks propagation in a layered rock mass during blasting of borehole charges and hydraulic fracturing. To calculate the stress state of an elastic rock mass with cracks, we used the boundary element method in a three-dimensional formulation. As a result of these calculations, the influence of the strength properties of rock mass layers on the shape of radial cracks and their area was determined.
Effect of elastic valve characteristics on pneumatic impact ring machine capacity
Authors: Primychkin AYu , Belozertseva LYu
Published: May 2021

The paper presents a case-study of the effect exerted by a ring-shaped elastic valve as a promising lock-and-control element of air distribution on the performance of a pneumatic impact ring machine. The design model of the machine is presented. The authors determine the blow energy and frequency of the machine, as well as the compressed air flow rate versus the preload of the valve and the elasticity modulus of the valve material. The recommendations on design of the elastic air distribution elements for pneumatic percussion machines subject to their operational conditions are given.
Dynamics of gravity-type pneumatic percussion machine for drain hole drilling
Authors: Tambovtsev PN
Published: May 2021

The author presents and justifies a construction diagram of a gravity-type pneumatic percussion machine for drain hole drilling with efficient penetration of casing in soil. The working cycle parameters of the machine, efficient design variables, as well as the blow energy, blow frequency and compressed air flow rate depending on the line pressure are determined by the numerical modeling. The weight, size and dynamics of the gravity-type machine are compared with the known analogous facilities.
Physical properties and fracture behavior of rocks in uniaxial and triaxial compression: A case-study of Zhdanovskoe deposit, Kola Mining and Metallurgical Company
Authors: Zemtsovsky AV , Kuznetsov NN , Pak AK
Published: May 2021

The paper presents the test data on properties of rocks from Zhdanovskoe deposit located in the Pechenga area of the Murmansk Region. The nature of the elastic energy accumulation in rock specimens and their susceptibility to uncontrollable fracture in the dynamic mode are determined. The uniaxial and triaxial compression test data are used to find mechanical properties and energy characteristics of rock specimens. The tested rocks are assessed as hard and susceptible to dynamic fracture, which is one of the criteria of rockburst hazard.
3D probabilistic cellular automation modeling of transition to fracture in rocks under loading
Authors: Kazunina GA , Cherednichenko AV
Published: May 2021

The three-dimensional model of the probabilistic cellular automaton, which has previously been constructed on the basis of the kinetic theory of strength, is studied in this paper. It describes the process of rock damage accumulation and formation of a damage cluster structure. Comparing the kinetic curves of damage accumulation and correlation functions of the model experiments, it is found that, depending on the sprouting probability of the damage cluster perimeter, which simulates the rate of material fracture under the action of local overstresses near the existing damage clusters, two qualitatively different modes of damage accumulation are observed in the 3D model. For the sprouting probabilities of the cluster perimeter higher than 0.2, the process of transition to irreversible fracture is significantly accelerated and becomes strongly correlated. Along with this, the best agreement of correlation functions in the model and in the physical experiments is observed for the sprouting perimeter probability values smaller than 0.2.
Improvement of technology and procedures of local rockburst hazard control
Authors: Tereshkin AA , Rasskazov IYu , Anikin PA , Gladyr AV , Migunov DS , Rasskazov MI
Published: May 2021

At some rockburst-hazardous deposits in Russian Far East and on the Kola Peninsula, the measurement of acoustic emission parameters is performed, and new data are obtained on hazardous features of confining pressure in different sites of mine fields. The measurement procedure is developed for local ground pressure control Prognoz L, and additional rockburst hazard criteria are substantiated for underground mines.
Study of structural and chemical transformations at mineral surface under laser infrared radiation
Authors: Leonenko NA
Published: May 2021

The effects of interaction of laser radiation with ore minerals originated from Far East deposits. The possible identification and further extraction of hard-to-recover gold and silver forms at surface of the melted matrix of the mineral is established. The structural and chemical transformations of the mineral surface exposed to laser radiation are investigated.
Preparation of frozen rock samples for shear tests
Authors: Maksimov MS , Kozlov DS
Published: May 2021

The paper presents the method to prepare frozen rock samples structurally consistent with blasted rock mass for shear tests at a laboratory scale. The proposed method makes it possible to assess strength characteristics of blasted rock mass.
Tests of centrifugal concentrator in processing of diamond-bearing sand with co-current gold recovery
Authors: Ochosov OYu , Matveev AI
Published: May 2021

The data are reported on the co-current gold recovery in the process for beneficiation of diamond-bearing sands from a number of deposits developed by Almazy Anabara Co. The company conducts co-current gold recovery at standard sluice facilities. The comparative data on gold recovery at Itomak centrifugal concentrator and a centrifugal-vibration concentrator (CVC), designed at IGDS SB RAS, are cited in the present paper. It is proved that CVC capacity allows as high as 92.8% gold recovery.
Finishing of gold-bearing concentrated products
Authors: Salomatova SI
Published: May 2021

The research data on the finishing centrifugal flotation of the pre-concentrated gold-antimony ore product are reported on a series of laboratory tests at a centrifugal flotation machine with peripherical discharge of the concentrate (CFM) and a mechanical flotation machine (FM). The selectivity of mineral particle detachment from the mineralized flotation froth moving along an inclined plane after flotation process running at different modes with/without a collector. It is demonstrated that the use of a collector makes it possible to control intensity and selectivity of material detachment from the froth layer. It is found that flotation finishing in the centrifugal flotation machine actually enables to improve the final concentrate characteristics.
Sintered Fe-Cr-Mo-Si-C alloys produced from pre-alloyed Fe-Cr based powders admixed with 4% SiC for high performance applications
Authors: Soe A.N. , Wila P. , Morakotjinda M. , Yotkaew T. , Karin P. , Ohtake N. , Tongsri R.
Published: May 2021

The use of pre-alloyed Fe-Cr based powders has been steadily increasing in the automotive industry. Mechanical properties can be tailored due to phase transformations controlled by alloying elements and cooling rates. Employing silicon carbide (SiC) as a source of alloying elements has been proved to be possible. In this study, three different pre-alloyed Fe-Cr based powders, namely Astaloy CrA, Astaloy CrL, and Astaloy CrM, were alloyed with 4 wt. % SiC powder. The powders were mixed and pressed into tensile test bars. The green compacts were sintered at 1250 °C for 45 minutes under the cracked ammonia gas and slowly cooled (<0.1°C/s) to room temperature. All experimental sintered alloys manifested a common feature resembling those of full pearlitic ductile irons, i.e., the feature consisted of black nodular particles enveloped with hyper-eutectoid steel matrix (grain boundary or pro-eutectoid cementite plus pearlite). The tensile testing indicated that Alloy-3 (Astaloy CrM + 4%SiC) was observed to have better mechanical properties in comparison with Alloy-1 (Astaloy CrA + 4%SiC) and Alloy-2 (Astaloy CrL + 4%SiC), apart from slightly lower elongation than Alloy-2. Regardless of SiC addition, the presence of chromium (Cr) content was observed to substantially influence mechanical properties and microstructure. According to the investigation of fracture surfaces by SEM, mixtures of shallow dimples and cleavage fractures were examined in the sintered alloys.
The effect of molybdenum on the microstructure and mechanical behaviour of the sintered Fe-Mo-Mn-Si-C composite
Authors: Nithimethakul Thunyamon , Karin Preechar , Ohtake Naoto , Wila Pongsak , Yodkaew Thanyaporn , Vetayanugul Bhanu , Morakotjinda Monnapas , Tongsri Ruangdaj
Published: May 2021

Experimental sintered Fe-Mo-Mn-Si-C composites were prepared from 3 different pre-alloyed Fe-Mo-Mn powders, namely Fe-0.50Mo-0.15Mn, Fe-0.85Mo-0.15Mn and Fe-1.50Mo-0.15Mn, mixed with fixed 4 wt.% silicon carbide powder. Sintered Fe-SiC composite was also prepared, as a reference material, from pure Fe powder mixed with fixed 4 wt.% silicon carbide powder. All specimens were processed by using the ‘press and sinter’ method. Sintering was performed in a vacuum furnace at 1250ºC for 45 minutes and slow cooling in the furnace. The microstructures of most sintered alloys showed a common feature consisting of a black particle enveloped with ferrite and pearlite. Sintered composites produced from high-molybdenum powders showed different matrices, in which some pearlite regions were replaced by BF/M- A structures. The Tensile and hardness test showed that the sintered alloys exhibited an increase of tensile strength, yield strength, and hardness with increasing molybdenum content. The pearlite + BF/M-A fractions of sintered composites played important roles in material strengthening. In the sintered composites produced from high-molybdenum powders, the carbide-free BF/M-A structure showed a promising strengthening effect.
Comparative study on the wood-based PLA fabricated by compression molding and additive manufacturing
Authors: Chansoda Kanjanaphorn , Suvanjumrat Chakrit , Chookaew Watcharapong
Published: May 2021

Additive manufacturing namely 3-Dimensional (3D) printing and it’s feeding materials are increasingly used for producing customized products. Fused Deposition Modelling (FDM) in conventional 3D printers is a cost-effective solution. This is due to the low cost of the machine and various size selections. Although the machine cost is reasonable, the filament material is a higher cost. In general, the current filament is priced about 4 times more than granulated plastic. Moreover, the special filament containing wood powder shows a high cost of approximately 20 times that of pellets. This work proposes a comparative study of the components obtained from different processes. Compression molding and no-mold techniques were used. A previous design, nozzle from extrusion concept, was also used for fabricating the specimens. PLA and wood-based PLA were carried out to produce the testing samples. The results showed that parts obtained from the compressive mold showed low tensile strength. It was indicated that the residue voids were significantly affected by its strength. Taking into account the 3D printed parts, the articles from the designed extruder present a higher strength than the results derived from the conventional 3D printer and compression machine. On the other side, it was found that the moving direction of the nozzle (raster angle) affected directly the maximum tensile strength. Furthermore, the neat PLA had higher stress than the wood-composite materials used for all fabrication methods. However, in the case of using an extrusion device, it represented the enhancing of mechanical strength, which was caused by the homogeneous texture of polymers melting in a hot barrel. In terms of fabrication cost, the molding technique showed the highest cost even though the feeding material has the lowest cost. A similar cost was found for providing parts from the conventional printer and our design nozzle. However, a pellet-based extruder would be printed the sample filled 15%wt, conventional but the 3D printer is unavailable. Furthermore, recycled materials or waste of 3D printed parts can be utilized by using a conceptual extruder.
Influences of cooling rate and carbon content microstructure and mechanical properties of sintered Fe-1.5Mo-xC alloys
Authors: Wanalerkngam Arisara , Boonmee Sarum , Srichumpong Thapanee , Morakotjinda Monnapas , Tosangthum Nattaya , Tongsri Ruangdaj
Published: May 2021

Sintered Fe-1.50Mo-xC alloys were produced by the sintering of powder compacts made from mixtures of pre-alloyed Fe-1.5Mo powder and varied carbon amounts (0.30-1.20 wt.% with 0.15 increment) followed by slow and fast cooling rates. The slowly cooled sintered Fe-1.50Mo-xC alloys (for carbon contents of up to 0.45 wt.%) showed microstructures consisting of polygonal ferrite grains and eutectoid transformation products. When carbon contents were higher than 0.45 wt.%, eutectoid transformation products were dominant. The fast-cooled sintered Fe-1.50Mo-xC alloys (for carbon contents of up to 0.75 wt.%) showed microstructures consisting of upper bainite. When carbon contents were higher than 0.75 wt.%, upper bainite and inverse bainite were dominant. Tensile strength and hardness values of sintered Fe-1.50Mo-xC alloys increased with increasing carbon content. In addition, fast cooling further enhanced mechanical properties of the sintered alloys. It was found that values of ultimate tensile strength (UTM) and hardness on slow and fast cooling rates were 385-565 MPa, 564-743 MPa, 43-78 HRB and 60-82 HRB, respectively.
Evaluation of wall functions for RANS turbulence models by unsteady lid-driven cavity flow
Authors: Suvanjumrat Chakrit , Loksupapaiboon Kittipos
Published: May 2021

Turbulence models do not perform well near walls because the Reynolds number in this interesting area is low. The wall functions and the advantage method can be efficiently used to model fluid flow at the near wall region. The Reynolds averaged Navier-Stokes turbulence models which had the developed wall functions in Open FOAM, the open source CFD software, were evaluated by the turbulent flow. The 3-D lid-driven cavity flow at the turbulence Reynolds number of 10,000 with various spanwise aspect ratio had been referred to validate these turbulence models. The comparison shown that the realizable k-ɛ turbulence model with the standard k and ɛ wall functions of OpenFOAM was the most powerful model to represent the velocity profile of water flow in the 3-D lid-driven cavities.
Crash analysis of sandwich composite electric microbus
Authors: Jongpradist P. , Limpanawisut S. , Siritana A. , Saardying P. , Saingam N. , Tangthamsathit P. , Chanpaibool P.
Published: May 2021

Sandwich composite is ideal for lightweight monocoque structure owing to not only its superiority in strength-to-weight ratio and specific flexural properties but also its manufacturability to any desired complex shape. In this work, an optimum lightweight design of monocoque composite sandwich-structure microbus subjected to bending and torsion stiffness criteria and natural frequency constraints is further investigated under crash conditions through finite element analysis. A composite sandwich panel made of 5.4-mm woven glass fabric-epoxy face sheets and 50-mm rigid polyurethane foam core is tested under low-velocity impact with a hemisphere headed impactor following ASTM D7136 to characterize the failure characteristics. An enhanced composite damage material model so-called MAT54 in LS-DYNA with damage progression in each lamina utilizing strength-based Chang-Chang criteria is implemented with various formulations to validate and compare for their efficiency and accuracy under impact test. The reduced-integration Balytschko-Tsay shell element with 5 through-thickness integration points is applied to the monocoque composite microbus model. The structural crashworthiness under the frontal crash of the bus at 20, 40 and 50 km/h to a rigid wall barrier is examined. The front structure absorbs the most frontal impact energy up to 60% and shows severe damage when the crash velocity is 40 km/h or higher. For the bus impact velocity of 50 km/h, the maximum deformation of the bus front is 809 mm resulting in the intrusion of the structure into the specified driver survival space. Design improvement of the sandwich structure should be further explored to enhance its energy absorption and safety of the bus under crash events.
Numerical simulations of cancer treatment prediction: modeling the influence of immunity
Authors: Ezaki Yuka , Nagayama Katsuya , Miura Ichiro
Published: May 2021

Malignant tumors, also called cancer or malignant neoplasms, are life-threatening tumors that invade the borders of other tissues or spread to other parts of the body and grow in various locations [1]. Recent evidence suggests that cancer cells generated by genetic mutations are eliminated by immune cells. Immune cells are immune cells that recognize and attack foreign substances, pathogens, and cancers in the body. A decline in immunity due to ageing or nutritional deficiencies, or due to immunosuppression is associated with increased risk of cancer cells [2]. Immunotherapy is a treatment method that activates the body’s innate immune function to eliminate cancer cells. This study, therefore, set out to assess the effect of immunotherapy using numerical simulations. Parameters, such as the conditions of cancer cell death with immune cells, cell division, and angiogenesis, were theoretically set and introduced into the model.
Emulation of battery discharge behaviour using programmable power supply based on LabVIEW
Authors: Tanruean N. , Charoenphonphanich C. , Yenwichai T. , Masomtob M.
Published: May 2021

This paper presents a battery simulator based on the actual electrical behaviour of the battery cells using power supply controlled by Laboratory Virtual Instrument Engineering Workbench (LabVIEW). Firstly, the behaviours of the battery are tested under experimental conditions including constant temperatures at 25C˚ and two different current loads at 0.5C and 1C. Secondly, the battery behaviours are analysed and applied in LabVIEW. The algorithms which are low pass filter, PID and others are implemented in LabVIEW to reduce standard deviations and errors. The current study found that the constant load at 0.5C and 1C, which controlled by the electronic load via LabVIEW, can emulate the battery voltage and the error relative is below 5 %. Further work is required to establish the optimization of the parameters in the battery management system (BMS) since a battery simulator uses power sources before the use of the battery management system (BMS) with a real battery.
Enhanced thermal performance in a square-duct heat exchanger with inclined square-rings
Authors: Khanoknaiyakarn Chitakorn , Promthaisong Pitak , Hoonpong Panuwat , Promvonge Pongjet , Skullong Sompol
Published: May 2021

An experimental work has been conducted to explore thermal and turbulent flow friction characteristics in a uniform heat-fluxed square-duct contained with inclined square-rings (SR). Experiments were performed for different geometric parameters of the SR elements, focused on their detailed effects on the optimal thermal performance. Influences of five different ring-to-duct height or blockage ratios (BR=b/H= 0.1, 0.15, 0.2, 0.25 and 0.3) on friction factor (f), Nusselt number (Nu), and thermal enhancement factor (TEF) in the square duct are investigated for Reynolds number (Re) from 4210 to 25,800. The inclination angle (a) and the ratio of axial pitch length of rings to the height of duct (called pitch ratio, PR=P/H) were kept constant at 60° and 3.0, respectively. The experimental result has shown that the SR insert gives greater heat transfer and friction loss than the plain duct acting alone. Increasing the blockage ratio (BR) results in the drastic enhancement in Nu and f values. The inserted duct with BR = 0.25 has the maximum TEF around 1.57. Comparing thermal performance at identical operating conditions, the SR insert at BR = 0.15 gives around 1.1 %, 2.3 %, 3.2 and 4.5 % higher than the one at BR = 0.2, 0.25, 0.3 and 0.1, respectively.
Investigation of pressure loss in a circular pipe under ultrasonic waves released along main stream flow
Authors: Treegosol Pongsapak , Priyadumkol Jetsadaporn , Katchasuwanmanee Kanet , Chaiworapuek Weerachai
Published: May 2021

Recently, ultrasound was discovered to have great potential in enhancing heat transfer from thermal systems., However, there is little information of the flow resistance, induced by its waves. Therefore, this research investigates the pressure loss of turbulent water flow in a circular pipe disturbed by 25 kHz ultrasound at the Reynolds number of 10,000, 12,500, 15,000, 17,500, 20,000, 22,500, and 25,000. The size of test section was modeled in accordance with the power plant’s condenser and the flow had been verified by the comparison of friction factor with theory. The maximum and minimum differences were 9.79 and 0.33%, respectively, confirming the reliability of the test setup. In this study, ultrasound was released along the mainstream flow from 3 and 15 transducers, installed upstream of the pipe. The results confirmed that the ultrasound was slightly affected on the friction loss of turbulent pipe flow. The average increase of pressure loss was 0.077% and 0.833% by the waves when they were emitted from 3 and 15 transducers, respectively. With very low inducement of flow resistance, ultrasound can be accounted as one of the most promising techniques for heat transfer enhancement, applicable to many thermal systems such as condensers, in the future.
Effect of low-frequency ultrasonic waves on heat transfer of laminar water flow over a heating flat plate
Authors: Phetchoo Satanon , Mingbunjerdsuk Jirachai , Katchasuwanmanee Kanet , Chaiworapuek Weerachai
Published: May 2021

This research investigates the effect of 40, 80, and 120 kHz ultrasound on heat transfer of laminar water flow over a heating flat plate using thin leaf thermocouples in a low turbulence water tunnel. The mainstream velocity was set at 0.127 m/s, corresponding to the local Reynolds number during 65,181 – 148,390 in the test section. The ultrasonic waves were released perpendicular to the mainstream and vertically from the upper wall at the distance of 0.15 m to the heating plate having constant heat flux of 1,040 W/m2. The results show that the ultrasound, having frequencies of 40 and 120 kHz provides the maximum Nusselt number up to 15% and 31%, respectively at the most downstream position of the test region. In the meantime, the 80 kHz waves slightly affect the heat transfer over a flat plate. Hence, in an attempt to employ the ultrasound for heat transfer enhancement over a flat plate, the distance and ultrasonic frequency must be well considered.
Analyze open channel for continuously low speed used carbon dioxide bubbles
Authors: Kirasamutranon L. , Kirasamutranon K. , Saimek S.
Published: May 2021

Designing a recirculating open-channel for continuously low speed in place of a towing tank required checking on its flow characteristics. There are many methods for checking the flow characteristics such as food coloring techniques, using buoys and hydrogen gas bubbles, etc. For this research, we use carbon dioxide bubbles which are caused by the reaction between sodium bicarbonate (NaHCO3) and hydrochloric acid (HCl) that is diluted in water until the acidity is equal to pH 3. Our experiments were carried at the area near the wall and the center of the test range at depths 6, 8 and 10 centimeters from the free surface level respectively. From the experimental results, the trend of water flow patterns in the center of the channel using food coloring needles technique tends to form the fluid flow close to the computational fluid dynamics (CFD) while the results from the carbon dioxide bubble technique are different compared with the two previous techniques by less than 20 percent, and the trends of the water flow pattern results of the numerical method, the food coloring needle, and the carbon dioxide bubble techniques. The tendency of the flow pattern in the same direction.
On the origin and correction for inner filter effects in fluorescence. Part II: secondary inner filter effect -the proper use of front-face configuration for highly absorbing and scattering samples
Authors: Ceresa Luca , Kimball Joseph , Chavez Jose , Kitchner Emma , Nurekeyev Zhangatay , Doan Hung , Borejdo Julian , Gryczynski Ignacy , Gryczynski Zygmunt
Published: May 2021

Fluorescence is an established technology for studying molecular processes and molecular interactions. More recently fluorescence became a leading method for detection, sensing, medical diagnostics, biotechnology, imaging, DNA analysis, and gene expression. Consequently, precise and accurate measurements in various conditions have become more critical for proper result interpretations. Previously, in Part 1, we discussed inner filter effect type I, which is a consequence of the instrumental geometrical sensitivity factor and absorption of the excitation. In this part, we analyze inner filter effect type II and discuss the practical consequences for fluorescence measurements in samples of high optical density (absorbance/scattering). We consider both the standard square and front-face experimental configurations, discuss experimental approaches to limit/mitigate the effect and discuss methods for correcting and interpreting experimental results.
Surfactant-free commercial electroless bath with low concentration of SiC nanoparticles to prepare the NiP-SiC nanocomposite coatings
Authors: Khodaei M , Gholizadeh A Mohammad
Published: May 2021

Fabrication of NiP-SiC nanocomposite coatings through the electroless deposition in a commercial electrolyte containing the low concentrations of SiC nanoparticles on carbon steel substrate was studied in this work. The confirmation of co-deposition of Ni matrix and SiC nanoparticles was investigated by evaluating the effect on morphology, crystal structure, and corrosion behavior of the heat-treated coatings which were investigated by scanning electron microscope, x-ray diffraction (XRD), and electrochemical measurements, respectively. The XRD results revealed that the heat-treated NiP and NiP-SiC coatings consisted of Ni and Ni3P phases, which the calculated faction of Ni3P phase for NiP and NiP-SiC samples is 58.2 and 62.2%, respectively. The corrosion resistance of nanocomposite samples is higher than that of pure NiP sample (9 to 76% corrosion inhibition efficiency. The tribological behavior of the coatings was characterized by microhardness measurement and ‘pin on disk’ wear test. By co-deposition of SiC nanoparticles, the hardness of heat-treated NiP is significantly increased (near 25%) and the wear loss is reduced (near 48%), especially at high sliding distance during wear test. The sample prepared through the surfactant-free electroless bath containing the 1 g l−1SiC nanoparticle showed the best corrosion as well as wear resistance.
‘Alpha clusters’ discovered on neutron-rich nuclei
Authors: Jarman Sam
Published: May 2021

“Alpha clusters” resembling helium-4 nuclei have been spotted on the neutron-rich surfaces of heavy atomic nuclei.
Accelerating egg yolks shed light on brain injuries
Authors: Jarman Sam
Published: May 2021

New insights into how brain injuries occur have been gleaned from how an egg yolk is deformed when rotational forces are applied to its outer shell.
Sextuply-eclipsing star system discovered
Authors: Cooper Keith
Published: May 2021

An unusual grouping of six gravitationally bound stars is more than an astronomical curiosity and could shed light star formation, as Keith Cooper explains
Breaking down barriers
Authors: Philpot Julian , Williams Tamia
Published: May 2021

In response to the careers article “On the road less travelled” (December 2020 pp45–46), in which Tamia Williams from Pace University in New York discusses her experiences as a Black physicist.
Against short-termism
Authors: Wolfe David
Published: May 2021

In response to Robert P Crease’s Critical Point article “Very deep thinking” (February p18), which argues that looking thousands – or hundreds of thousands – of years into the future is vital for humanity.
Structural transition from a ring to a folded structure of a seamless nanobelt
Authors: Inui Norio , Makimoto Taichi , Moritani Kousuke
Published: May 2021

Stable structures of a rolled seamless belt of atoms arranged in a two-dimensional honeycomb lattice such as a carbon nano-belt, transit from a ring-shaped structure with a rotational invariance to folded structures as the circumference of the belt increases. Using molecular mechanics, we consider the size dependence of the structures obtained by simulated annealing. In addition, the relationship between the variety of metastable structures and the rate of temperature decrease during annealing is also examined. Furthermore, we investigate the effects of the van der Waals interaction between the surfaces on the structural transitions.
Differential expression of phosphorylated MEK and ERK correlates with aggressive BCC subtypes
Authors: Rahman Muhammad M , Herath Dimalee , Bladen John C , Atkar Ravinder , Pirzado Muhammad S , Harwood Catherine , Philpott Michael P , Neill Graham W
Published: May 2021

Basal cell carcinoma (BCC) is associated with aberrant Hedgehog (HH) signalling through mutational inactivation of PTCH1; however, there is conflicting data regarding MEK/ERK signalling in BCC and the signalling pathway interactions in these carcinomas. To address this, expression of active phospho (p) MEK and ERK was examined in a panel of 15 non-aggressive and 14 aggressive BCCs. Although not uniformly expressed, both phospho-proteins were detected in the nuclei and/or cytoplasm of normal and tumour-associated epidermal cells however, whereas phospho-MEK (pMEK) was present in all non-aggressive BCCs (14/14), phospho-ERK (pERK) was rarely expressed (2/14). In contrast pERK expression was more prevalent in aggressive tumours (11/14). Interestingly, pMEK was only localized to the tumour mass whereas pERK was expressed in tumours and stroma of aggressive BCCs. Similarly, pERK (but not pMEK) was absent in mouse BCC-like tumours derived from X-ray irradiated Ptch1+/− mice with stromal pERK observed in myofibroblasts of the aggressive variant as well as in the tumour mass. RNA sequencing analysis of tumour epithelium and stroma of aggressive and non-aggressive BCC revealed the upregulation of epidermal growth factor receptor- and ERK-related pathways. Angiogenesis and immune response pathways were also upregulated in the stroma compared with the tumour. PTCH1 suppressed NEB1 immortalized keratinocytes (shPTCH1) display upregulated pERK that can be independent of MEK expression. Furthermore, epidermal growth factor pathway inhibitors affect the HH pathway by suppressing GLI1. These studies reveal differential expression of pERK between human BCC subtypes that maybe active by a pathway independent of MEK.
Antibiotic Utilization in Deceased Organ Donors
Authors: Anesi Judith A , Lautenbach Ebbing , Han Jennifer , Lee Dong Heun , Clauss Heather , Climaco Antonette , Hasz Richard , Bilker Warren B , Molnar Esther , Alimenti Darcy , West Sharon , Tolomeo Pam , Blumberg Emily A
Published: May 2021

Antibiotic use in deceased organ donors has not been previously described. In a retrospective cohort of 440 donors, we found 427 (97%) received at least one antibiotic course, 312 (71%) received broad-spectrum antibiotics, and 61 (14%) received potentially redundant antibiotics during their terminal hospitalization, suggesting a need for stewardship.
Cardionephrology from the point of view of the cardiologist: no more agree to disagree—getting to ‘yes’ for every patient
Authors: Burlacu Alexandru , McCullough Peter A , Covic Adrian
Published: May 2021

Whether one wants to or not, interactions between the heart and the kidneys exist and manifest nevertheless. Both from theoretical and clinical perspectives, it seems the need for a subspecialty of cardionephrology seems justified. Our editorial is a cardiologist perspective on the article by Diez and Ortiz published in Clinical Kidney Journal related to the ‘need for a cardionephrology subspecialty’. We analysed the historical similarities of the emergence of already ingrained clinical fields with the current needs in the cardionephrology sector. We motivated our approach based on novel cardiovascular diagnostic and therapeutic developments and significant pathophysiological differences from a cardiological perspective, accounting for the foundation of a novel sustainable medical field. One of the sensitive issues we also addressed was the operationality and applicability of the principles. We answered with some examples from high-risk debatable contexts the question of where a cardionephrologist should be integrated. Clarifying the operationality aspects would be a positive shift towards improving guidelines adherence in managing complex patients. In conclusion, we underline that the necessity of a cardionephrologist must be addressed from an operational and scientific perspective, with the ultimate goal of reducing mortality and complications in cardiorenal patients.
MetamORF: a repository of unique short open reading frames identified by both experimental and computational approaches for gene and metagene analyses
Authors: Choteau Sebastien A , Wagner Audrey , Pierre Philippe , Spinelli Lionel , Brun Christine
Published: May 2021

The development of high-throughput technologies revealed the existence of non-canonical short open reading frames (sORFs) on most eukaryotic ribonucleic acids. They are ubiquitous genetic elements conserved across species and suspected to be involved in numerous cellular processes. MetamORF (https://metamorf.hb.univ-amu.fr/) aims to provide a repository of unique sORFs identified in the human and mouse genomes with both experimental and computational approaches. By gathering publicly available sORF data, normalizing them and summarizing redundant information, we were able to identify a total of 1 162 675 unique sORFs. Despite the usual characterization of ORFs as short, upstream or downstream, there is currently no clear consensus regarding the definition of these categories. Thus, the data have been reprocessed using a normalized nomenclature. MetamORF enables new analyses at locus, gene, transcript and ORF levels, which should offer the possibility to address new questions regarding sORF functions in the future. The repository is available through an user-friendly web interface, allowing easy browsing, visualization, filtering over multiple criteria and export possibilities. sORFs can be searched starting from a gene, a transcript and an ORF ID, looking in a genome area or browsing the whole repository for a species. The database content has also been made available through track hubs at UCSC Genome Browser. Finally, we demonstrated an enrichment of genes harboring upstream ORFs among genes expressed in response to reticular stress.

Database URL  https://metamorf.hb.univ-amu.fr/
Case report of recurrent haemoptysis in an older patient with repaired tetralogy of Fallot
Authors: Vanderschueren Emma , Budts Werner , Van De Bruaene Alexander
Published: May 2021

Background

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart defect. Although most infants nowadays undergo surgical repair approximately at the age of 6 months with excellent outcomes, older patients typically underwent a staged approach with an initial systemic-to-pulmonary Blalock–Taussig–Thomas (BTT) shunt reducing hypoxaemia, followed by surgical TOF repair at an older age (with takedown of the BTT shunt). Late complications related to the BTT shunt are rare.

Case summary

We report a case of recurrent haemoptysis late after classic BTT shunt and subsequent surgical TOF repair. Axial imaging indicated a stellate nodule with isotope accumulation in the right upper lung lobe, whereas bronchoscopy showed a rope-like structure in the bronchus to the right upper lung lobe. The patient underwent a lobectomy of the superior right lobe, with identification of what appeared to be the old suture around the BTT shunt. Anatomopathology confirmed diffuse necrotizing inflammation with erosion into the bronchus which eventually caused haemoptysis.

Discussion

Management of older patients with congenital heart disease requires a thorough knowledge of the anatomy and surgical history of the patient. Although late complications related to a BTT shunt are rare, a residual shunt, endocarditis, pseudoaneurysm, or chronic inflammation with haemoptysis may occur.
Differences in Vaginal Microbiota, Host Transcriptome, and Proteins in Women With Bacterial Vaginosis Are Associated With Metronidazole Treatment Response
Authors: Serebrenik Joyce , Wang Tao , Hunte Richard , Srinivasan Sujatha , McWalters Jessica , Tharp Gregory K , Bosinger Steven E , Fiedler Tina L , Atrio Jessica M , Murphy Kerry , Barnett Rebecca , Ray Laurie R , Krows Meighan L , Fredricks David N , Irungu Elizabeth , Ngure Kenneth , Mugo Nelly , Marrazzo Jeanne , Keller Marla J , Herold Betsy C
Published: May 2021

Background

Bacterial vaginosis (BV) treatment failures and recurrences are common. To identify features associated with treatment response, we compared vaginal microbiota and host ectocervical transcriptome before and after oral metronidazole therapy.

Methods

Women with BV (Bronx, New York and Thika, Kenya) received 7 days of oral metronidazole at enrollment (day 0) and underwent genital tract sampling of microbiome (16S ribosomal RNA gene sequencing), transcriptome (RNAseq), and immune mediator concentrations on day 0, 15, and 35.

Results

Bronx participants were more likely than Thika participants to clinically respond to metronidazole (19/20 vs 10/18, respectively, P = .0067) and by changes in microbiota composition and diversity. After dichotomizing the cohort into responders and nonresponders by change in α-diversity between day 35 and day 0, we identified that transcription differences associated with chemokine signaling (q = 0.002) and immune system process (q = 2.5 × 10–8) that differentiated responders from nonresponders were present at enrollment. Responders had significantly lower levels of CXCL9 in cervicovaginal lavage on day 0 (P < .007), and concentrations of CXCL9, CXCL10, and monocyte chemoattractant protein 1 increased significantly between day 0 and day 35 in responders vs nonresponders.

Conclusions

Response to metronidazole is characterized by significant changes in chemokines and related transcripts, suggesting that treatments that promote these pathways may prove beneficial.
Suitability of open digital species records for assessing biodiversity patterns in cities: a case study using avian records
Authors: Sultana Marufa , Storch Ilse
Published: May 2021

Openly available species observation records on various online platforms achieve good coverage in urban areas. Thus, such digital data could provide a basis for biodiversity assessments in cities. Here, we investigated suitability of open digital species occurrence data, compared with systematically field surveyed data, in Freiburg, Germany (a Western city) and Dhaka, Bangladesh (a global-South city). We focused on resident bird species richness as an indicator of local biodiversity. We collected avian records for urban areas from ‘ornitho.de’ in Freiburg and ‘gbif.org’ in Dhaka. Additionally, we conducted point count surveys at several urban locations in both cities. Using these records, we prepared three grid (cell size 250 m × 250 m) based datasets—open digital dataset (i.e. records compiled from well-surveyed grid cells), field surveyed dataset (i.e. records of systematic bird surveys) and combined dataset (i.e. digital data and field data combined). We compared the relationship of resident bird richness with different habitat factors by applying linear regression models, separately using each of the three datasets. We assessed suitability of data from online platforms by comparing the variables retained after model selection based on digital data versus field surveyed data. We found that field surveyed data and combined data did not alter general understanding of the key driving factors of bird richness patterns we obtained from open digital data. This held for both case examples, Freiburg vs. Dhaka, respectively. This suggests that open digital data from well-surveyed urban locations can provide a suitable basis to assess drivers of biodiversity patterns within cities.