bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal field prediction in DED manufacturing process using Artificial Neural Network
Authors: Fetni Seifallah , Pham Quy Duc Thinh , Tran Van Xuan , Duchêne Laurent , Tran Hoang Son , Habraken Anne Marie
Published: April 2021

In the last decade, machine learning is increasingly attracting researchers in several scientific areas and, in particular, in the additive manufacturing field. Meanwhile, this technique remains as a black box technique for many researchers. Indeed, it allows obtaining novel insights to overcome the limitation of classical methods, such as the finite element method, and to take into account multi-physical complex phenomena occurring during the manufacturing process. This work presents a comprehensive study for implementing a machine learning technique (artificial neural network) to predict the thermal field evolution during the direct energy deposition of 316L stainless steel and tungsten carbides. The framework consists of a finite element thermal model and a neural network. The influence of the number of hidden layers and the number of nodes in each layer was also investigated. The results showed that an architecture based on 3 or 4 hidden layers and the rectified linear unit as the activation function lead to obtaining a high fidelity prediction with an accuracy exceeding 99%. The impact of the chosen architecture on the model accuracy and CPU usage was also highlighted. The proposed framework can be used to predict the thermal field when simulating multi-layer deposition.
Experimental investigation and optimization of thermal gradients by infrared welding
Authors: Perrin Henri , Senoussaoui Noha-Lys , Dubief Cécile Leroy , Vaudemont Régis
Published: April 2021

Infrared welding technology is currently used in the automotive industry to assemble very complex composite shapes made of short glass fiber reinforced polymers. Such applications are targeted more towards short joining times than towards the optimization of adhesive properties. Through this work, the authors joined their efforts on the experimental investigation of driving mechanisms and their optimization, enabling the welding of high-performance materials typically selected for aeronautics applications. The thermal field through the thickness and on the surface was investigated. The best configuration of the LM-PAEK/C laminate presented a single lap shear (SLS) strength of 43.5 MPa with a standard deviation of 0.7 MPa compared to a strength of 24.9 MPa with a standard deviation of 2.3 MPa obtained with the welding configuration without insulation. These results highlight the major effect of a thermal gradient during infrared welding. It is specific to infrared welding to observe that the major resulting defects are located not at the interface area but inside the composite substrate, where voids, generated during the heating step, are unable to be reconsolidated during pressure application. The impact of the decompaction behavior on the thermal gradient was studied through a MATLAB© implemented 1D numerical model, developed internally and called “LysIR”.
Numerical Investigation of a New Production Method for Face Gearings Incorporating Material Predistribution – Pin-to-Gear Method
Authors: Weiss Andre , Liewald Mathias
Published: April 2021

The research subjects of current investigations at the Institute for Metal Forming Technology (IFU) Stuttgart include the manufacture of face gearings. Usually, gearings are produced by means of a coining process, which causes high process forces that considerably restrict the geometry of the teeth in terms of the height-to-width ratio. In order to avoid these problems, a new forming process has been developed. This technology offers significant advantages, such as the reduction of process forces and the ability to manufacture the required tall and acuminate tooth elements through a cold-forming process. This paper describes the design and functionality of the novel pin-to-gear forming process. In this paper, the operating principle of the method is presented first of all. The new pin-to-gear process is then compared to conventional coining and the free-divided-flow (FDF) process developed at IFU Stuttgart in 2018. This examination takes the form of a numerical simulation using DEFORM-2D software. To investigate the influence of preform parameters on the form filling of the tooth cavities, parameter studies in design and geometry are conducted. Process limits regarding geometric constraints are presented alongside possibilities for increasing process reliability. Through this investigation, the potential and opportunities of the innovative pin-to-gear forming process will be illustrated.
Analysis of the sliding mechanics of NBR thread pattern
Authors: Spina Roberto , Galantucci Luigi Maria , Lavecchia Fulvio , Cavalcante Bruno , Doca Thiago , Luca Cataldo De
Published: April 2021

The objective of the present work is to study materials properties and performance of the footwear thread to develop and implement an analytical-numerical model capable of simulating their performance. The numerical results simulation was carried out, analyzing the sliding mechanisms of shoe-floor and evaluating the contact pressure and vertical stress. An experimental procedure, supported by a numerical model, was implemented for computing the evolution of the tangential force over several load increments.
Experimental investigation of effect of printing direction and surface roughness on the mechanical properties of AlSi10Mg-alloy produced by selective laser melting
Authors: Vysochinskiy Dmitry , Akhtar Naureen , Nordmo Tord , Strand Mathias Rabjerg , Vyssios Adrian , Bak Morten Kollerup
Published: April 2021

The additive manufacturing has initially gained popularity for production of non-loadbearing parts and components or in the fields where the material strength and ductility are less important such as modelling and rapid prototyping. But as the technology develops, availability of metal additive manufacturing naturally dictates the desire to use the produced components in load-bearing parts. This requires not-only a thorough documentation on the mechanical properties but also additional and independent research to learn the expected level of variation of the mechanical properties and what factors affect them. The presented paper investigates strength, ductility, hardness, and microstructure of the AlSi10Mg alloy produced by the selective laser melting (SLM). The mechanical properties were determined through a series of uniaxial tension tests and supplementary hardness tests and rationalized with the microstructure evolution with regard to printing direction and heat treatment. The paper also addresses the effect of surface roughness on the mechanical properties of the material, by comparing the machined and net shape tension samples. As expected, the as-manufactured AlSi10Mg-alloy appears to be a semi-brittle alloy, but its microstructure can be altered, and ductility increased by a proper heat-treatment. The effect of surface layer removal on the measured mechanical properties is of particular interest.
Extrusion and characterization of aluminum/graphene composites
Authors: Negendank Maik , Faezi Hamidreza Rabi , Ovsianytskyi Oleksandr , Goerke Oliver , Gurlo Aleksander , Müller Sören
Published: April 2021

Since its first synthesis in 2004 graphene was characterized intensively and exceptional properties in terms of e.g. mechanical strength, stiffness and electrical as well as thermal conductivity were revealed. These properties make graphene very attractive to be applied as additive in composite materials e.g. to increase strength and conductivity compared to the pure matrix material. In this study graphene nano platelets (GNP) in contents of 0. 5%, 1.0 % and 1.5 % were added to pure (99.7 %) aluminum powder and dispersed via EIRICH mixer method. This method is very appealing since homogenous mixtures can be achieved in significantly lower time when compared to e.g. the ball milling process. After subsequent cold compaction the composite materials were extruded with three different extrusion ratios. The influence of GNP content and extrusion ratio on the specific extrusion pressure is characterized as well the resulting rod surface quality, respectively. The effects of GNP content and extrusion ratio on homogeneity of graphene dispersion in the aluminum matrix, the relative density of the composite as well as hardness were also investigated.
Measurement of fiber wrinkles and shear angles of double dome forming parts
Authors: Graef Jasmin , Weiß Björn , Engel Bernd
Published: April 2021

This study presents the results of a double dome forming study for fiber reinforced thermoplastics to give an estimation about wrinkles size and fiber angle values. The parts were formed with an industry-oriented process at different forming temperatures and fiber directions (0 °/ 90 ° and ±45 °). They were formed without blank holder to allow wrinkling. The investigated material is a glass fiber –reinforced polyamide 6 with three layers of twill fabric (TEPEX® Dynalite 102-RG600(3)/47 %). The wrinkles are measured with a laser scanner. The shear angles were calculated using image analysis in MATLAB. It determines the fiber directions and calculates the fiber angles at their crossing points. Afterwards, areas with positive and negative shear angle values will be identified and discussed: These areas are in an axially symmetrical formation. At one side there are positive shear angles and on the other side there are negative shear angles. But results show, that absolute values differ. Furthermore, the results show, that shear angles increase with increasing forming temperatures and wrinkles size decrease. The results of this work will be used for the validation of FE forming models of double dome part in further studies.
Research into the effect of the 3D-printing mode on changing the properties of PETG transparent plastic
Authors: Petrov Pavel , Agzamova Diana , Pustovalov Vladimir , Zhikhareva Elena , Saprykin Boris , Chmutin Igor , Shmakova Natalya
Published: April 2021

A study of mechanical and optical properties of samples of transparent plastic Polyethylene terephthalate glycol (PETG) manufactured by additive technology Fused Filament Fabrication (FFF) was carried out. PETG plastic is used in medicine, particularly in dentistry due to its unique set of properties: strength, elasticity, resistance to aggressive environments, transparency. Preserving the complex of properties of PETG plastic, including transparency, during 3D-printing is an important technical task. In order to solve this task a set of studies of PETG laboratory samples was carried out. The optimum modes of 3D printing were determined to provide PETG samples with increased strength properties, preservation of elastic properties and optical transparency of the material. The increase in the optical transparency of the material is provided by an additional post-treatment of the printed samples surface with a chemical reagent. The influence of technological parameters of the post- treatment mode on the mechanical and optical properties of the printed samples has been investigated. The novelty of the work consists in a comprehensive study of the modes of manufacturing products from PETG by technology FFF with subsequent post-treatment, allowing to preserve the transparency of the polymeric material.
Accuracy in microstructure measurements in highly directional processes
Authors: Magro Tommaso , Ghiotti Andrea , Bruschi Stefania , Simonetto Enrico
Published: April 2021

Flowforming is an advanced forming technique to produce net shape axisymmetric components, with high dimensional accuracy, based on the simultaneous action of a rotating mandrel and multiple translational rollers. The deformation mechanism has great influence on the uniformity of microstructure, with a gradient in the grain size from the inner to the outer portion of the component cross section, with elongated grains in the rollers feed direction. The highly directional deformation of the microstructure, both along the radial and axial direction, may reach extreme values in the case of large reduction and this aspect may introduce significant uncertainties in the evaluation of the mechanical properties of the final parts (i.e. microhardness, maximum elongation, yield strength) due to the computational methodologies used to estimate the average grain size. The paper focuses on the most frequently used measurement methods to assess the measurement accuracy for the correlation with the local variations of mechanical properties. The reference case for the investigations is the flowforming of AA6082 tubes, processed at different process parameters to change the shape of the grain and the gradient along the radius. Comparisons were carried out with regards to methods that allow measuring the grain size using zero-dimensional features (points), one-dimensional features (lines), and two-dimensional features (areas), respectively with the triple-point count method, the Heyn intercept method and the Jeffries planimetric method.
Phase change driven adaptive mesh refinement in PFEM
Authors: Bobach Billy-Joe , Falla Romain , Boman Romain , Terrapon Vincent , Ponthot Jean-Philippe
Published: April 2021

The particle finite element method (PFEM) is used to simulate a simple phase change problem. This is a first step towards the simulation of additive manufacturing (AM) processes at the meso-scale, where the liquid melt pool interacts with the surrounding solid material and undergoes phase change. The focus of this paper lies on strategies to deal with the release or absorption of latent heat in the PFEM, especially with regard to mesh refinement. We briefly describe how mesh refinement in PFEM works and how it can be chosen specifically to achieve convergence despite the highly non-linear latent heat term. It is found that good agreement with the literature can be achieved on a simple 1D phase change test case, while using an automatic local mesh refinement.
Deep neural networks as surrogate models for time-efficient manufacturing process optimisation
Authors: Zimmerling Clemens , Schindler Patrick , Seuffert Julian , Kärger Luise
Published: April 2021

Manufacturing process optimisation usually amounts to searching optima in high-dimensional parameter spaces. In industrial practice, this search is most often directed by human-subjective expert judgment and trial-and-error experiments. In contrast, high-fidelity simulation models in combination with general-purpose optimisation algorithms, e.g. finite element models and evolutionary algorithms, enable a methodological, virtual process exploration and optimisation. However, reliable process models generally entail significant computation times, which often renders classical, iterative optimisation impracticable. Thus, efficiency is a key factor in optimisation. One option to increase efficiency is surrogate-based optimisation (SBO): SBO seeks to reduce the overall computational load by constructing a numerically inexpensive, data-driven approximation („surrogate“) of the expensive simulation. Traditionally, classical regression techniques are applied for surrogate construction. However, they typically predict a predefined, scalar performance metric only, which limits the amount of usable information gained from simulations. The advent of machine learning (ML) techniques introduces additional options for surrogates: in this work, a deep neural network (DNN) is trained to predict the full strain field instead of a single scalar during textile forming („draping“). Results reveal an improved predictive accuracy as more process-relevant information from the supplied simulations can be extracted. Application of the DNN in an SBO- framework for blank holder optimisation shows improved convergence compared to classical evolutionary algorithms. Thus, DNNs are a promising option for future surrogates in SBO.
A methodology for mould conformal cooling channels optimization exploiting 3D printing
Authors: Arrivabeni Edoardo Battista , Tomasoni Daniele , Giorleo Luca , Barbato Maurizio Claudio
Published: April 2021

With the advent of 3D printing, it is now possible to produce any part or system with an approach than makes design much deeply interlaced with production. In this scenario, CAE has gained power thanks to the possibility of thinking and then manufacture ideas that go well beyond what was possible in the past. This design approach is perfectly suitable to push forward mould conformal cooling performance. In this work, a coupling of CAD, CFD and 3D printing supported by experimental tests was applied to define a design procedure for conformal cooling channels. In particular, cooling channels for a mould were engineered via CAD, then tested via CFD and, after an initial optimization procedure, the chosen design was 3D printed in specimens suitable to be mounted on a heat exchanger (HX) experimental test rig that was especially adapted for the scope. Fluids temperature, volume flow rates and heat transfer performance were measured. A feedback loop was considered to link measurements and channels redesign. Results together with design and testing procedures are reported and commented.
Finite Element Analysis of Stretch Forming of an Open Profile Made of Ultra-High Strength Martensitic MS1500 Steel
Authors: Görtan Mehmet Okan , Türkmen Ümit
Published: April 2021

Stretch forming process is primarily used for generating curved structures from sheet metals such as car body panels or aircraft fuselage panels. Although there are large number of studies about stretch forming, these investigations focus mainly on flat sheet metals. However, various parts especially in the automotive industry, such as passenger car fenders are first preformed to a profile and afterwards stretch formed to generate desired final geometry. Moreover, as a consequence of weight reduction activities, these fender parts are usually made of ultra-high strength steels (UHSS) in the last two years. In the current study, stretch forming characteristics of an open profile made of martensitic UHSS (MS1500) are investigated using finite elements method (FEM). Used geometry was an asymmetrical hat profile which was preformed using roll forming prior to stretch forming. Mechanical properties of the material used is characterized using tensile test and modeled using Swift isotropic strain hardening rule. Strain and stress distribution along the bend section, geometry and springback in the final part as well as forming force have been investigated using finite element (FE) simulations. A twist has been observed in the final product along its longitudinal axis. To validate the FE results, experiments have been conducted. Twist problem is also detected in the manufactured samples. The amount of springback in produced part was similar to the experiments. It is found that FE simulations can model stretch forming process of open profiles accurately.
Milling Tool Optimization by Topology Optimization Technique
Authors: Tomasoni Daniele , Giorleo Luca , Ceretti Elisabetta
Published: April 2021

In milling operations, the weight of the milling tool greatly affects the motion speed of the mandrel, especially when a complex tool path must be performed. Thus, it is essential to realize more lightweight tools, without a significant decrease in the mechanical and production performance. Traditionally, due to the limitation of the conventional manufacturing processes, the design of a new milling tool cannot be too much complex and thus cannot fully satisfy the mentioned goals. Nowadays, thanks to the topology optimization technique and the additive manufacturing (AM) technologies, such as the selective laser melting (SLM), it is possible to realize more complex part geometries to obtain more lightweight and high-performance tools. In this paper, a new design of a milling tool with a weight reduced by 30% is presented; SLM process has been selected to realize the milling tool. In order to minimize the use of support structures, required by the SLM process to correctly realize the desired part, the new geometry has been little modified. A more lightweight milling tool has been produced and every support structure has been successfully removed from the component.
Deformation due to sliding of single and woven carbon tows in dry and epoxy-lubricated conditions
Authors: Smerdova Olga , Benchekroun Omar , Brunetière Noel
Published: April 2021

This experimental work focuses on the evaluation of deformation mechanisms due to sliding between carbon fiber tows with a flat tool in dry and lubricated with liquid resin conditions. The experiments were carried out on manually woven and single tows. The effect of angle between tow axes and sliding direction was also studied. The topography of the tows in contact with a sliding transparent glass plate was measured with a 3D optical microscope before and after sliding. These measurements revealed a decrease of roughness with sliding in all tested conditions, a contraction of lubricated single tows in perpendicular to sliding orientation, and high residual displacements in lubricated woven tows in 0°/90° orientation and dry single tows in perpendicular to sliding orientation.
A comparison of different hardening rules on a multi-step global manufacturing process modeling
Authors: Britez Diego , Werda Sana , Laheurte Raynald , Darnis Philippe , Cahuc Olivier
Published: April 2021

The main difficulty presented by the simulation of a global process that includes different forming stages is the correct characterization of the material state at the end of each of these stages, which in turn, are the initial point of the following process. Hardening variables are capable of characterizing the state of the material, which, after a plastic transformation, varies according to the direction of the solicitation and its intensity. The present work carries out an analysis of the influence in the election of the hardening rule used in the behavior law, comparing the most used approach. For a work piece solicited by combined efforts in multiple stages, results are obtained by numerical simulation. A correct choice will allow obtaining reliable predictions, not the solicitations but also to the final geometry and the dissipated energy in the global process, allowing an eventual optimization of such process.
Model Calibration of 3D Printed Lattice Structures
Authors: Mancini Edoardo , Utzeri Mattia , Farotti Emanuele , Sasso Marco
Published: April 2021

Nowadays cellular materials are receiving great attention for their excellent mechanical properties, being applied in energy absorbers or in structural components having optimized mass distribution. In this paper stretch-dominated lattice structures have been considered. A 3D periodic lattice structure of different cell size, TPMS (triply periodic minimal surface), made of epoxy resin by DLP technology was studied. Compression tests at different strain rate (10-3 to 103 1/s) have been performed and a constitutive model to assess the experimental findings has been calibrated.
Design and Optimization of Processing Conditions for a Recent Quenched and Partitioned Steel
Authors: El-Shenawy Eman Hassan , Hedia Hoda Nasr El-Din , Kama-El-Din Mai Mohamed , Badwy Hoda Refaiy
Published: April 2021

Q&P steels as a "Third Generation" of (AHSS) exhibit excellent tensile properties, which enable producing lightweight sections for the automotive industry and at the same time keep safety requirements. This research aims to predict the proper processing conditions for developing ultra-high-strength Q&P steel with a novel chemical composition of 0.37 C-3.65 Mn- 0.65Si- 0.87 Al- 1.5 Ni- 0.05P, wt. %. To design and optimize proper heat treatment conditions, the phase diagram, CCT curve, and critical temperatures of these alloys were first implemented using THERMO-CALC and JMATE PRO software and Gleeble 3500 machine. The heat treatment process included full austenitization, then quenching at 120°C followed by partitioning at 450°C for different times. The tensile properties, microstructure, and retained austenite volume fraction of heat-treated steel was studied at room temperature by tensile testing machine, optical microscope, and XRD. The finding summarized that partitioning of this steel for 100 s during processing had developed Q&P steel with ultra-high-strength of 1104 MPa with maximum total elongation and strength elongation balance 8.1 % and 8932 MPa %, respectively. The optical micrograph showed that heat-treated specimens at different partitioning times have had a microstructure of tempered martensite, carbide free bainite, and retained austenite. Besides, the retained austenite volume fraction has decreased with increasing partitioning time, which may be due to carbide precipitation during partitioning.
Cutting Performance of Austenitic and Duplex Stainless Steels with Drills of Three Cutting Edges
Authors: Marouvo João , Ferreira Pedro , Simões Fernando
Published: April 2021

Austenitic and duplex stainless steels are considered be the best in corrosion resistance among different grades of stainless steels. Due to high strength, duplex stainless steels applications are increasingly as an alternative to the austenitic stainless steels. In this sense, the machining study of this materials is an important issue, in order to better understand the performance of the tools and the quality of the parts manufactured for high-demand industries. In this research, the machinability of both stainless steels was evaluated in the drilling operation, using drills with three cutting edges. This type of drill geometry is particularly useful when conventional solid carbide drills fail. The drill point of triple edge is very stable, demonstrating optimal positioning accuracy and better performance in deep bores. Using the same tool geometry, a comparative analysis of drilling performance on austenitic and duplex stainless steels was made. In experimental procedure, external low-pressure cooling or internal high-pressure cooling was applied alternatively. The cutting vibration, the tool wear, the roughness and the hole diameter accuracy were evaluated in the series of holes made. The obtained results show that the most important factor to increase the number of holes made is the use of high-pressure internal cooling. When external cooling is used, AISI 304 have a worse behaviour than duplex stainless steel, due to greater susceptibility to built-up-edge formation and work hardening. The tool deterioration is mainly non-uniform chipping for external cooling and flank wear for internal cooling.
The Hadrami Diaspora: A "diaspora for others" in the Indian Ocean
Authors: Walker Iain
Published: April 2021

The term diaspora has, over the past two decades, become ubiquitous both in the vernacular and in academia, to the point that it appears to have lost its acuity as an analytical concept, often meaning little more than a group of migrants. In an attempt to reinvigorate the concept, this article invokes the notion of the “diaspora for others”: a diaspora that has a coherence across space and time, linking the various localisations of a diaspora, and the homeland. The case study is the Hadrami diaspora, and by tracing the links between members of the diaspora, this article demonstrates how the diaspora, although marked by internal differences, nevertheless displays an overall cohesion that grants it a stable and distinct identity as a spatially dispersed community, thus recalling the original sense of the term diaspora.
A Forgotten Hero?: The Influence of Andrew Murray during the Scottish Wars of Independence, 1296-1298
Authors: Clegg Lewis
Published: April 2021

William Wallace is a highly renowned Scottish legend, who led his nation to victories against the English in battles such as Stirling Bridge. There are also some other less known figures who contributed to this success but are lost in the Wallace romance. The most notable of these figures is Andrew Murray. Murray is a forgotten hero in Scottish legacy, and played a major role in Wallace's success. Andrew Murray was a strong military leader and was greatly admiried by the lower classes of Scotland. Murray's character and tactics as a military leader were instrumental in Wallace's campaigns against the English, particularly at the Battle of Stirling Bridge. This was made further evident by his death in late 1297 and his absence in the Scottish defeat at the Battle of Falkirk the following year.
BUSINESS STRATEGY FORMULATION OF DAYA MINYAK, Ltd
Authors: Satiawarman Anugerah , Sutandra Tanti , Munir Ningky Sasanti
Published: April 2021

The weakening of crude oil price had caused the performance of Daya Minyak, Ltd decline. The efforts to improve had succeeded in improving performance, but it was still below the industry average. Therefore, in 2020 a research was carried out aimed at systematically formulating Daya Minyak, Ltd business strategy for the years 2021-2024. This applied research was conducted qualitatively, using the business strategy formulation model from David and David (2016) where external strategic issues were compiled in the External Factor Evaluation (EFE) matrix and internal strategic issues in the International Factor Evaluation (IFE) matrix. The weighted value of the EFE matrix is 2.93 and the weighted value of the IFE matrix is 2.97, which meant that the future business strategy is to hold and maintain. Two alternative strategies, market penetration, and product development were developed using the Internal-External (IE) matrix and the TOWS matrix. Two priority strategies, namely a strategy to increase market penetration through integrated services at low costs and a product development strategy through increasing local content with international standards are determined by the Quantitative Strategic Planning Matrix (QSPM).
Autotoxic effects of applied vanillic acid on Dynamic succession of soil microbial community
Authors: Shao R.X. , Ma Z. Q. , Jiang Y. H , Han X. R. , Zang C. Q. , Yang J. F. , Lin Y. , Han M. , Bai H. Z. , Huang Y. Q.
Published: April 2021

We studied the degradation of vanillic acid in soil was studied by high performance liquid chromatography and gas chromatography. Illumina MISEQ high-throughput sequencing was used to identify the abundance of bacteria and fungi in soil. The results showed that when the concentration of vanillic acid decreased to a certain level in the soil, its degradation rate became slow. The application of vanillic acid gradually decreased the total number of bacterial OTUs in soil, while the total number of fungal OTUs increased. At the same time, the richness and diversity of bacteria were always higher than fungi. Key microbial taxa at different degradation stages of vanillic acid were identified at the phylum and genus level, including bacteria (Proteobacteria, Firmicutes, Actinobacteria, Chloroflexi, Methylibium, Methylobacillus, Aeromicrobium, Pseudonocardia) and Fungi (Ascomycota, Zygomycota, Basidiomycota, Rhodotorula, Mortierella
Allelopathic effects of Festuca arundinacea variety Millennium2 leaf aqueous extracts on seedlings growth of 10 fescue varieties
Authors: Xu Xiao , Liang Zhongyin , Li Xiaoyu , Yang Ruixia , Xu Jichen
Published: April 2021

The allelopathic effects of fescue (Festuca arundinacea) variety ‘Milennium’ 2 leaf aqueous extracts on 10 fescue varieties were assayed. The 50 mg·ml-1 treatment increased the biomass and physiological indices (soluble sugar content, malondialdehyde content and root activity), whereas the 100 mg·ml-1 and 150 mg·ml-1 treatments were inhibitory. There was variable response of fescue varieties to different treatments, the varieties (Aries, Millennium2, and Free star) were most sensitive to the leaf extracts, while Greenlabel, Lenge maste, and Arid3 varieties were least sensitive. The treatments most affected the physiological factor, relative electrolyte leakage, followed by the soluble sugar content, malondialdehyde content, and root activity. These results suggested that sowing an appropriate combination and proportion of grass varieties may be better to improve the lawn quality than the continuous use of a single grass variety.
Bioactivity of allelochemicals isolated from the roots of Echinacea purpurea L. Moench on Amaranthus viridis L., Portulaca oleracea L. and Microcystis aeruginosa
Authors: Jing-Lei Xiao , Yan-Xin Zhang , Cheng-Guo Jia , Ming-Zhe Zhang , Wei Chen , Yu-Bin Zhang , Bin Li , Dong-Sheng Wei , Gang Wu , Xing-Lin Du , Jian-Chun Qin
Published: April 2021

Based on the bioassay-guided strategy, we isolated 6-six allelochemicals [cichoric acid (I), 1,3-dicaffeoylquinic acid (II), 4,5-dicaffeoylquinic acid (III), chlorogenic acid (IV), 1-hydroxy-2-phthoic acid (V), echinacoside (VI)] from the roots of Echinacea purpurea (L.) Moench. Their structures were identified by nuclear magnetic resonance (NMR) and electrospray ionization mass spectrometry (ESI-MS) spectroscopic data. The bioassays studies included allelopathic and algicidal activities to test the effects of extracts and isolated fractions against the test weeds (Amaranthus viridis L., Portulaca oleracea L. and Microcystis aeruginosa Kutzing). At 100 µg/mL, compound (II) inhibited the shoot length and germination of A. viridis and P. oleracea weeds with the germination RI of -0.95±0.04 and -0.95±0.02, respectively. Furthermore, compound (III) showed the strongest inhibition of root length of P. oleracea L. We also found that compounds I-VI have algicidal activity. The compound (I) at low inoculum (5.0×102 cells mL-1) and high inoculum (1.0×104 cells mL-1), showed the highest algicidal activity of 78 % and 87.67 % 6 h after the treatment at 5 µg mL-1 respectively.
Screening of broad-leaved tree species to restore Eucalyptus urophylla Blake forest on Sanjiao Island, China
Authors: Chang L.X. , Zhang F.Y. , Zhang Z.K. , Chen B.M. , Ye S.S. , Zhang Q.Y.
Published: April 2021

This study aimed to test the allelopathic effects of Eucalytus urophylla Blake. forest soil on 5-native broad-leaved tree species (Bauhinia purpurea L., Acacia confusa Merr., Acacia podalyriifolia A. Cunn. ex G. Don., Celtis sinensis Pers. Liquidambar formosana Hance) to select suitable species for restoration of E. urophylla forest. Three types of soils [E. urophylla soil, other plants soil and bare soil] were used to determine their allelopathic potential. The total phenols concentrations in soil were measured, and the correlations between total phenols and plant growth indices were analyzed. E. urophylla soil significantly inhibited the basal diameters of Bauhinia purpurea L. and Acacia confusa Merr. and biomass of Acacia podalyriifolia A. Cunn. ex G. Don. but significantly improved the biomass of Celtis sinensis Pers. and diameter of Liquidambar formosana Hance. The total phenols in soil accounted for these results, except for A. podalyriifolia. Thus, L. formosana, C. sinensis and A. confusa can be suggested as suitable tree spp to establish mixed stands with E. urophylla. Besides, B. purpurea, A. podalyriifolia, A. confusa and L. formosana can be used for restoration in bare soil, while B. purpurea, A. confusa and L. formosana are suitable species to restore vegetation in other plants soil. Keywords: Acacia confuse, Acacia podalyriifolia, Allelopathy, bare soils, Bauhinia purpurea, broad-leaved trees, Celtis sinensis, Eucalytus urophylla, E. urophylla soil, forest restoration, island, other plants soil, rhizosphere soil, total phenols
Plant Allelopathy Research and Development: 60 Years (1960-2019)
Authors: Wang J.L. , Zhang Z.H. , Hu C. , Fu R.Y. , Hu G.
Published: April 2021

environment. It is one of the hotspots in Ecology and Agronomy. In this paper, we have retrieved from the Web of Science (WoS) SCI-E database the allelopathy-related studies (1960-2019). The Annual Number of Publications, Authors, Countries, Institutions, Journals and Keywords were analyzed by the bibliometric method to determine the research trends and hotspot changes in this field over the past 6 decades. From 1960-2019, the WoS database included 4,114 studies in the field of plant allelopathy. During this period of 60 years, the number of publications has gone through three stages: (i). Initial Stage (1960-1990), (ii). Growing Stage (1991-2009) and (iii). Stable Stage (2010-2019). The studies were conducted by 9,956 authors at 2,166 institutions across 100 countries. The United States, China, and Japan have the highest number of publications. The top three institutions with the highest number of publications are the Chinese Academy of Sciences, Kagawa University and USDA, USA. The top three authors are H. Kato-Noguchi, F.A. Macias, and C.H. Kong. The major Journals in this field are: (i). Allelopathy Journal, (ii). Journal of Chemical Ecology and (iii). Plant and Soil. The results of keyword clustering showed that the main research directions in this field are: (i). Metabonomics undergoing allelopathy, (ii). Functions of allelopathy substances, (iii). Molecular biology, (iv). Allelopathy of aquatic plants, (v). Alien plants invasion and (vi). Application of plant allelopathy in agroforestry production. Plant allelopathy is a research field that aims to maintain stable development. Future studies should focus on strengthening the cooperation among international scholars in plant allelopathy research and improving the output in frontier and hotspot areas.
Allelopathic effects of ginsenoside on soil sickness, soil enzymes, soil disease index and plant growth of Ginseng
Authors: Zhan Yu , Wang Enpeng , Wang Huan , Chen Xue , Meng Xiangru , Li Qiong , Chen Changbao
Published: April 2021

Soil sickness of ginseng (Panax ginseng C. A. Mey.) has become a major limiting factor in ginseng cultivation. We found that Total Ginsenoside in Ginseng Root (TSPG) significantly decreased the activities of soil urease, acid phosphatase and laccase. Its high concentration of TSPG (10.00 mg L-1) significantly reduced the activity of soil sucrose. Besides, the TSPG can inhibited the growth of ginseng and increased the incidence of disease. Therefore, allelopathic effects of TSPG may be one of the main causes of Soil Sickness in ginseng.
Spectrophotometric determining of caffeine content in the selection of teas, soft and energy drinks available on the Croatian market
Authors: Vuletic N. , Bardic L. , Odzak R.
Published: April 2021

This study aimed to determine concentrations of caffeine in the samples of the selected
brands of teas, soft carbonated and energy drinks that are commercially available on the
Croatian market. Quantitative analysis of caffeine content in the chosen beverage samples
was done with UV/Vis spectrophotometric method. Chloroform was used as the solvent
and concentrations of caffeine were measured at the wavelength of 274 nm for three
samples of each of the selected beverages. Among the analyzed tea samples the highest
caffeine concentration was found in Franck's Black Tea (1471.021 ppm) and the lowest in
Naturavita's Green Tea with Ginger (588.138 ppm). Between the analyzed carbonated soft
drinks, the highest caffeine concentration was measured in Fresh Cola (136.036 ppm) and
the lowest in Sky Cola (48.198 ppm). The highest caffeine concentration in the analyzed
energy drink samples was measured in Hell energy drink (394.670 ppm) while the lowest
was in Coca Cola Energy drink (173.574 ppm). The results of this study gave preliminary
information about caffeine levels in often consumed teas, carbonated soft drinks and
energy drinks in Croatia. The caffeine content in the analyzed teas and drink samples in
this study was under the allowed one except for Red Bull and Hell.
Issues related to animal blood into food products: a review paper
Authors: M.S. Siti Jamilah , A.F. Nurrulhidayah , A. Azura , Mat Jubri S.M. , Rohman A. , T. Nur Azira , R. Arieff Salleh , O. Rashidi
Published: April 2021

The rapid development of science and technology has unveiled a new horizon for the food
industry by transforming blood into useful food products. This practice seems in line with
the sustainable development goal to be implemented by 2030 to improve the efficiency of
resources, reduce wastage and to avoid draining natural resources which can lead to
environmental degradation. The practice of transforming blood into various food products
possesses the potential to minimize harmful environmental issues resulting from blood
disposal into land and water. The aim of this review paper to explore the issues related to
animal blood into food products because the use of animal blood derivatives are
prohibited according to Islamic perspectives and some of religious practitioners. The
researcher relied on library research to accomplish the writing process. Sources such as
academic journals, governmental agency portals, research papers, thesis, journal articles
and trusted websites were used as references. Therefore, this paper aspires to provide
insights to researchers to carry out more research in different scopes of studies particularly
on the utilization of blood-derived products which can be a sensitive subject among
Muslims and other religious practitioners.
Potential Impact of Exercise-Associated Amenorrhea and Subsequent Estrogen Therapy on Cardiovascular Disease Risk Factors in Pre-Menopausal Athletes: A Research Protocol
Authors: Afjeh Niki Sadat , Lamba Priyanka , Eski Alefiya
Published: April 2021

Introduction: Women with exercise-associated amenorrhea (EAA) have impaired pulsatile gonadotropin-releasing hormone (GnRH) release that disrupts sufficient estrogen secretion, causing hypoestrogenism. As there is limited research on the influence of hypoestrogenism on cardiovascular health in pre-menopausal women, the purpose of this study is to assess its effect on the concentrations of estrogen and early cardiovascular diseases (CVD) risk factors – nitric oxide (NO), endothelin-1 (ET-1), and E-selectin – in women with EAA.
Methods: A total of 90 participants between the ages of 18-35 will be selected based on the inclusion criteria of athleticism status (8 hours of structured physical activity/week) and body mass index (BMI) range of 18.5-24.5. Out of the 90 participants, 45 will have EAA and 45 will have regular menstrual status. Exclusion criteria: Smokers, women on contraceptives and those with pre-existing CVD and respiratory health conditions/family history of these conditions. Baseline data of estrogen and CVD risk factor concentrations will be obtained from all 90 participants through bi-weekly blood draws and serum analysis in the first month of the 7-month study. The amenorrheic, athletes (n=45) will receive 0.025 mg of 17-β estradiol (E2) transdermally via estrogen patches daily for months 2-7 of the study. Blood will be collected bi-weekly from these amenorrheic, athletes (n=45) during months 2-7 to quantify estrogen and CVD risk factor concentrations during the intervention. Statistical analysis: 2-way Analysis of Variance (ANOVA) test to compare the levels of E2 and CVD risk factors prior to and following estrogen treatment of amenorrheic, athletic subjects.
Discussion: Although there are many cardiovascular risk factors which can be used as markers to determine the effect of EAA on cardiovascular health, NO, ET-1, and E-selectin may serve to provide more accurate analysis due to less present confounding factors as other markers. Anticipated results include increased NO and decreased ET-1 and E-selectin concentrations following estrogen therapy.
Conclusion: Diagnosis and management of menstrual irregularities like EAA is imperative for maintaining good cardiovascular health. Further research to determine whether estrogen therapy can be used as a long-term solution for women with EAA, and whether it should be provided in conjunction with nutritional intervention is recommended.
“Ngā pakiaka a Te Rēhia, ka tipua i te ao rangatahi” An Intersectional Analysis of Kapa Haka and Healing for Rangatahi Māori
Authors:   , Gifford Joanne
Published: April 2021

“Pāpaki whakapapa, Pāpaki ahurea, Pāpaki oranga, Ki ngā pakiaka a te rēhia, Kia tipua ai i te ao Rangatahi.” This thesis provides insights into the experiences of rangatahi Māori and Kapa Haka. Through an intersectional and Kaupapa Māori lens, it explores the potential of Kapa Haka in the realms of belonging, identity and healing. In doing so, it illustrates the dynamic value of Kapa Haka for alleviating cultural disconnection and facilitating healing within the context of current contemporary challenges such as the mental health crisis, climate change tensions and discrimination that rangatahi Māori in Aotearoa New Zealand face today. The aim of this work is to contribute to the wave of Kaupapa Māori research demonstrating the transformative impact of Māori tikanga, kawa, and knowledges in alleviating the impact of colonial violence on the wellbeing of our people. This thesis draws on Wānanga as a powerful method for co-constructing knowledge with rangatahi Māori. Claiming Wānanga as a method contributes to the decolonial project not by inventing something new, but by recognising the power and sophistication of Indigenous knowledge making processes. This thesis weaves together the experiences of ten Wānanga participants with autoethnographic reflections, literature, cultural theory and contemporary discussion to provide nuanced glimpses into the complex entity that is Kapa Haka today.
PENINGKATAN HASIL BELAJAR IPS KENAMPAKAN ALAM DAN KEADAAN SOSIAL NEGARA TETANGGA MELALUI SNOWBALL THROWING
Authors: Sohifah Sohifah
Published: April 2021

Pembelajaran di kelas pada umumnya masih diwarnai dengan menggunakan strategi pembelajaran ekspositori Siswa sebagai subjek yang belajar dan guru merupakan satu-satunya sumber belajar bagi siswa. Guru menerangkan materi pembelajaran dengan ceramah, siswa mendengarkan kemudian siswa diberi tugas untuk mencatat hal-hal penting dari pokok bahasan. Permasalahan penelitian ini  Bagaimanakah Peningkatan Hasil Belajar IPS materi kenampakan alam dan keadaan sosial negara tetangga melalui pembelajaran Snowball Throwing pada siswa kelas VI semester I tahun pelajaran 2016-2017 di SDN 1 Kamulan? Tujuanini melaksanakan pem-belajaran model Sowball Throuwing   meningkatkan hasil belajar IPS materi kenampakan alam dan keadaan sosial negara-negara tetangga Indonesia. Dari hasil analis didapatkan bahwa pembelajaran  Snowball Throwing  dapat meningkatkan hasil belajar IPS siswa Kelas VI di SD Negeri 1 Kamulan. Hal ini dapat dilihat   Nilai rata-rata  siklus I 69,44 dan siklus II   77,22 Ketuntasan belajar   siklus I  i 73% dan   siklus II   89%

Pembelajaran di kelas pada umumnya masih diwarnai dengan menggunakan strategi pembelajaran ekspositori Siswa sebagai subjek yang belajar dan guru merupakan satu-satunya sumber belajar bagi siswa. Guru menerangkan materi pembelajaran dengan ceramah, siswa mendengarkan kemudian siswa diberi tugas untuk mencatat hal-hal penting dari pokok bahasan. Permasalahan penelitian ini  Bagaimanakah Peningkatan Hasil Belajar IPS materi kenampakan alam dan keadaan sosial negara tetangga melalui pembelajaran Snowball Throwing pada siswa kelas VI semester I tahun pelajaran 2016-2017 di SDN 1 Kamulan? Tujuanini melaksanakan pem-belajaran model Sowball Throuwing   meningkatkan hasil belajar IPS materi kenampakan alam dan keadaan sosial negara-negara tetangga Indonesia. Dari hasil analis didapatkan bahwa pembelajaran  Snowball Throwing  dapat meningkatkan hasil belajar IPS siswa Kelas VI di SD Negeri 1 Kamulan. Hal ini dapat dilihat   Nilai rata-rata  siklus I 69,44 dan siklus II   77,22 Ketuntasan belajar   siklus I  i 73% dan   siklus II   89%