ARTICLE | doi:10.20944/preprints202111.0566.v1
Subject: Engineering, Civil Engineering Keywords: fibre reinforced concrete; simulation; cohesive crack; fibre cocktail
Online: 30 November 2021 (12:08:45 CET)
Fibre reinforced concrete (FRC) has become an alternative for structural applications due its outstanding mechanical properties. The appearance of new types of fibres and the fibre cocktails that can be configured mixing them has created FRC that clearly exceed the minimum mechanical properties required in the standards. Consequently, in order to take full advantage of the contribution of the fibres in construction projects, it is of great interest to have constitutive models that simulate the behaviour of the materials. This study aimed to simulate the fracture behaviour of five types of FRC, three with steel hooked fibres, one with a combination of two types of steel fibres and one with a combination of polyolefin fibres and two types of steel fibres, by means of an inverse analysis based on the cohesive crack approach. The results of the numerical simulations defined the softening functions of each FRC formulation and have pointed out the synergies that are created through use of fibre cocktails. The information obtained might suppose a remarkable advance for designers using high-performance FRC in structural elements.
ARTICLE | doi:10.20944/preprints201910.0050.v1
Subject: Engineering, Civil Engineering Keywords: cohesive fracture of fibre reinforced concrete; softening functions; fracture behaviour; glass fibre reinforced concrete; polyolefin fibre; steel fibres
Online: 4 October 2019 (11:46:47 CEST)
Fibre reinforced cementitious materials (FRC) have become an attractive alternative for structural applications. Among such FRC, steel and polyolefin fibre reinforced concrete and glass fibre reinforced concrete are the most used ones. However, in order to exploit the properties of such materials structural designers need constitutive relations that reproduce FRC fracture behaviour accurately. This contribution analyses the suitability of multilinear softening functions combined with a cohesive crack approach for reproducing the fracture behaviour of the FRC previously mentioned. The implementation performed accurately simulates the fracture behaviour while being versatile, robust and efficient from a numerical point of view.
ARTICLE | doi:10.20944/preprints201812.0065.v1
Subject: Engineering, Construction Keywords: fibre reinforced concrete; polyolefin fibres; fibre distribution; fracture behaviour; structural fibres
Online: 5 December 2018 (07:57:24 CET)
Polyolefin fibre reinforced concrete (PFRC) has become an attractive alternative to steel for the reinforcement of concrete elements mainly due to its chemical stability and the residual strengths that can be reached with lower weights. The use of polyolefin fibres can meet the requirements in the standards, although the main constitutive relations are based on the experience with steel fibres. Therefore, the structural contributions of the fibres should be assessed by inverse analysis. In this study, the fibre dosage has been fixed at 6kg/m³ and both self-compacting concrete and conventional concrete have been used to compare the influence of the positioning of the fibres. An idealized homogeneous distribution of the fibres with such fibres crossing from side to side of the specimen has been added to self-compacting concrete. The experimental results of three-point bending tests on notched specimens have been reproduced by using the cohesive crack approach. Hence, the constitutive relations were found. The significance of this research relies on the verification of the formulations found to build the constitutive relations. Moreover, with these results it is possible to establish the higher threshold of the performance of PFRC and the difficulties of limiting the first unloading branch typical of fracture tests of PFRC.
ARTICLE | doi:10.20944/preprints202109.0002.v1
Subject: Life Sciences, Biochemistry Keywords: soft texture rice; dietary fibre prediction; soluble dietary fibre; -glucan; pectin; arabinoxylan
Online: 1 September 2021 (09:20:53 CEST)
To date, most people prefer softer and stickier rice with high glycaemic index, which has led to the study of the association between the dietary fibre profile and the textural properties to balance between the eating quality, and health benefits. A slight variation was observed in the dietary fibre composition among rice varieties with different amylose content. The percentage of insoluble dietary fibre (IDF) in whole grain rice varied from 1.65–4.32 while the percentage of soluble dietary fibre (SDF) ranged from 0.26–1.37. We demonstrated that the SDF/IDF ratio was higher in soft texture rice with low amylose and it shared a negative correlation with hardness and chewiness of cooked whole grain rice determined by a texture analyser, which suggested that the distribution of SDF throughout the rice endosperm influences the reduction of the hardness of cooked rice. According to the importance of dietary fibre, we proposed a simple linear regression method to estimate the amount of IDF and total dietary fibre with r = 0.97 and 0.92, respectively, of whole grain rice based on its bran layer, determined by the alternative alkaline method. Furthermore, low amylose rice has higher content of -glucan and pectin, which are classified as soluble dietary fibre, than high amylose rice. The percentage of -glucan and pectin in whole grain rice ranged from 0.03 and 0.07 respectively, for high amylose rice to 0.14 and 0.27 respectively for low amylose rice,
Subject: Engineering, Electrical & Electronic Engineering Keywords: optical fibre data; transmission; microcomb
Online: 15 March 2020 (15:20:23 CET)
Micro-combs [1-4] - optical frequency combs generated by integrated micro-cavity resonators – offer the full potential of their bulk counterparts [5,6], but in an integrated footprint. The discovery of temporal soliton states (DKS – dissipative Kerr solitons) [4,7-11] as a means of mode-locking micro-combs has enabled breakthroughs in many fields including spectroscopy [12,13], microwave photonics , frequency synthesis , optical ranging [16,17], quantum sources [18,19], metrology [20,21] and more. One of their most promising applications has been optical fibre communications where they have enabled massively parallel ultrahigh capacity multiplexed data transmission [22,23]. Here, by using a new and powerful class of micro-comb called “soliton crystals” , we achieve unprecedented data transmission over standard optical fibre using a single integrated chip source. We demonstrate a line rate of 44.2 Terabits per second (Tb/s) using the telecommunications C-band at 1550nm with a spectral efficiency – a critically important performance metric - of 10.4 bits/s/Hz. Soliton crystals exhibit robust and stable generation and operation as well as a high intrinsic efficiency that, together with a low soliton micro-comb spacing of 48.9 GHz enable the use of a very high coherent data modulation format of 64 QAM (quadrature amplitude modulated). We demonstrate error free transmission over 75 km of standard optical fibre in the laboratory as well as in a field trial over an installed metropolitan optical fibre network. These experiments were greatly aided by the ability of the soliton crystals to operate without stabilization or feedback control. This work demonstrates the capability of optical soliton crystal micro-combs to perform in demanding and practical optical communications networks.
ARTICLE | doi:10.20944/preprints201901.0264.v2
Subject: Materials Science, Polymers & Plastics Keywords: hybrid composites, thermal analysis, kenaf, carbon fibre, epoxy
Online: 21 February 2019 (03:30:31 CET)
The effects of carbon fiber hybridisation on the thermal properties of woven kenaf reinforced epoxy composites kenaf fibre were studied. Woven kenaf hybrid composites at the different weave designs of plain and satin, and fabric count of 5 × 5 and 6 × 6 were manually prepared by vacuum infusion technique. Thermal properties of pure carbon fibre and hybrid composites were conducted by using thermogravimetric analyser (TGA) and differential scanning calorimeter (DSC). It was found that at high kenaf fibre content showed better thermal stability while the highest thermally stable was found in pure carbon fibre composite. The TG and DTG results showed that the amount of residue decreased in plain-designed hybrid composite compared to satin-designed hybrid composite. The DSC data revealed that the presence of woven kenaf increase decomposition temperature.
REVIEW | doi:10.20944/preprints202209.0464.v1
Subject: Life Sciences, Other Keywords: wheat aleurone; dietary fibre; extraction process; antioxidant; bread; arabinoxylans
Online: 29 September 2022 (09:00:46 CEST)
The wheat aleurone layer is, according to millers, the main bran fraction. It is a source of nutritionally valuable compounds, such as dietary fibres, proteins, minerals and vitamins, that may exhibit health benefits. Despite these advantages, the aleurone layer is scarce on the market, probably due to issues related to its extraction. Many processes exist with some patents, but a choice must be made between the quality and quantity of the resulting product. Nonetheless, its potential has been studied mainly in bread and pasta. While the nutritional benefits of aleurone-rich flour addition to bread agree, opposite results have been obtained concerning its effects on end-product characteristics (namely loaf volume and sensory characteristics), thus ensuing different acceptability responses from consumers. However, the observed negative effects of aleurone-rich flour on bread dough could be reduced by subjecting it to pre- or post-extracting treatments meant to either reduce the particle size of the aleurone’s fibres or to change the conformation of its components.
ARTICLE | doi:10.20944/preprints202205.0382.v1
Subject: Physical Sciences, Applied Physics Keywords: flexible fibre; flow medium; aerodynamic shape; drag; scaling laws
Online: 27 May 2022 (10:46:59 CEST)
The study of a flexible body immersed in a flowing medium is one of best way to find its aerodynamic shape. This Letter revisited the problem first studied by Alben, Shelley and Zhang (Nature 420, 479-481, 2002). The aerodynamic shape of the fibre is found by simpler approach and universal drag scaling laws of the flexible fibre in flowing medium are proposed by using dimensional analysis. The Alben scaling laws is being generalized and confirmed to be universal. Our study show that the Alben number is a measurement of maximum curvature of the fibre forced by dynamic pressure. A complete Maple code is provided for finding aerodynamic shape of the fibre in the flowing medium.
ARTICLE | doi:10.20944/preprints201908.0008.v1
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: basalt fibre; fabric; magnesium; centrifugal cast; metal matrix composite
Online: 1 August 2019 (04:57:31 CEST)
Magnesium is one of the lightest structural metal used in different industrial sector and many works are present in literature about the study of its reinforcement by fillers addition. Basalt fibres are natural fillers with good mechanical properties, excellent resistance to high temperature and lower cost than carbon fibres. For these aspects, in the last years they are increasingly used in the production of composite materials with polymeric matrices. However, very few information are presents in literature about the use of basalt fibres as reinforcement in metal matrix composite materials. It is well known that the impregnation of fibres reinforcement affects the mechanical behavior of composites materials. The aim of this study is to investigate the impregnation and the behavior of basalt fibres in a magnesium alloy composite material manufactured by a centrifugal casting technique.
ARTICLE | doi:10.20944/preprints201804.0372.v1
Subject: Materials Science, Surfaces, Coatings & Films Keywords: hemp bast fibre; hydrothermal processing; KOH activation; activated carbon
Online: 28 April 2018 (12:29:14 CEST)
Synthesis of activated carbon from waste biomass is of current interest towards sustainability. The properties of biomass derived activated carbon largely depends on the carbonization process. This study reports preparing extremel high surface area mesoporous activated carbon from hemp bast fibre using hydrothermal processing. Processing in hot water (390-500oC), then activation using KOH and NaOH was investigated at different loading ratios. The described approach was found to enhance the mesoporosity (centered at 3.0 to 4.5 nm) of the hemp derived activated carbon (HAC) from activation (confirmed by BJH pore size distribution and TEM imaging). BET results showed that the product has an extremely high surface area (2425 m2/g) while the surface functional groups (-OH, COOH, C=C/C-C) were confirmed and quantified by XPS and FTIR results. Increasing KOH concentration was found to enhance the surface area with an optimum biochar to KOH ratio of 1:3. The crystallite domain size of HAC was determined using Raman spectroscopy of different wavelengths. The procedure described in this study is an environmentally friendly scalable route for the mass production of activated carbon using hemp fiber.
Subject: Materials Science, Biomaterials Keywords: Biodegradable labeling; Decomposition; Fibre; Micro plastic; PVAL; PHA; Shotgun wad
Online: 10 May 2021 (15:35:36 CEST)
Parts of shotgun cartridges are a significant source of plastic litter in the marine environment. Empty cartridge shells may not be picked up by the hunter who fired them, and plastic wads that serve to separate the propellant from the shot load, are lost down-range when a shot is fired. Such litter items constitute a cosmetic and aesthetic problem on coastlines and may cause harm to marine animals and in the later stages of decomposition break down into harmful micro plastic particles. There exists no reliable estimate of the global exposure of marine ecosystems to this plastic source. However, in some countries it has been subject to closer examination, including for example, Denmark where the annual contribution of plastic wads into marine systems was estimated to 600,000 pieces (c2 tonnes), and the accumulated density of washed-up items (both wads and shells) was 3.7 items per 100 m coastline. Increasing awareness of this problem has caused scientists, hunters’ communities and governments to suggest altered practice including transition to the use of biodegradable cartridge components, first and foremost wads as this item is invariable lost during hunting. Several manufacturers provide shotgun cartridges containing biodegradable wads based on different types of materials, including fibers and various types of plastics, for example PVAL (poly(vinyl alcohol)) and PHA (polyhydroxyalkanoate). In this paper, we review the most recent literature on the amounts and related environmental hazards of plastic dispersed from hunting ammunition into marine ecosystems. We summarize the market availability of shotgun cartridges with biodegradable wads and discuss chemical, technical, economical and legal aspects of a transition to the use of such products.
ARTICLE | doi:10.20944/preprints202104.0786.v1
Subject: Engineering, Automotive Engineering Keywords: Hybrid fibre-reinforced concrete; thermal conductivity; spalling; residual mechanical strength.
Online: 30 April 2021 (11:13:43 CEST)
Over the years, leaked fluids from the aircraft caused severe deterioration of the airfield pavement. The combined effect of hot exhaust from the auxiliary power unit of military aircraft and spilt aviation oils caused rapid pavement spalling. If the disintegrated concreted pieces caused by spalling is sucked into the jet engine, it may cause catastrophic damage to the aircraft engine or physical injury to maintenance crews. This study investigates the effectiveness of incorporating hybrid fibres into ordinary concrete to improve the residual mechanical and thermal properties to prevent spalling damage of pavement. Three fibre reinforced concrete samples made with micro steel fibre and polyvinyl alcohol fibre with a fibre content of zero, 0.3%, 0.5% and 0.7% by volume fraction. These samples were exposed to recurring high temperature and aviation oils. Tests were conducted to measure the effects of repeated exposure on the concrete's mechanical, thermal and chemical characteristics. The results showed that polyvinyl alcohol fibre reinforced concrete suffered a significant loss of thermal properties and residual mechanical strength than the micro steel fibre reinforced concrete. However, hybrid fibre reinforced concrete performed better in retaining higher residual properties, and no spalling of concrete was observed.
ARTICLE | doi:10.20944/preprints201910.0031.v1
Subject: Engineering, Civil Engineering Keywords: sfrc; non-destructive testing; quality control; electromagnetic induction; radar; fibre
Online: 2 October 2019 (12:49:23 CEST)
The authors of the paper have made an attempt to detect the fibre content and fibre spacing in a steel fibre reinforced concrete (SFRC) industrial floor. Two non-destructive testing (NDT) methods: an electromagnetic induction technique and a radar-based technique were applied. The first method allowed to detect the spacing in subsequent layers located in the thickness of the slab. The result of the second method was a 3D visualization of the detected fibre in the volume of concrete slab. The conducted tests showed aptitude and limitations of the applied methods in estimating fibre volume and spacing. The two techniques also allowed to locate the areas with relatively low fibre concentration which are very likely to be characterized by low mechanical properties.
Subject: Engineering, Civil Engineering Keywords: polyolefin fibre reinforced concrete; fracture behaviour; size effect; bending tests
Online: 18 March 2019 (10:36:28 CET)
The reinforcement of concrete by using polyolefin fibres may be considered in structural design to meet the requirements of the applicable code rules. In order to achieve a reliable use of such a composite material, use of full-scale real structures is needed. The conversion of lab testing data into real practice properties is challenging and significantly influenced by various aspects, among which the size effect is a key one. Given that the available literature does not report coinciding conclusions about such an effect on quasi-brittle materials reinforced with fibres, further research is justified. Therefore, this work studies the behaviour of notched beams with three proportional sizes by using self-compacting polyolefin reinforced concrete with a fibre volume fraction of 1.1%. Flexural testing was carried out according to the standard EN-14651, with the results revealing the existence of the size effect. In addition, a reduction of the residual strength identified in the larger specimens was observed in fracture surfaces with equal fibre content.
ARTICLE | doi:10.20944/preprints202105.0470.v1
Subject: Engineering, Civil Engineering Keywords: Size effect; Polyolefin fibre reinforced concrete; Trilinear softening function; Cohesive model
Online: 20 May 2021 (10:03:06 CEST)
Size effect on plain concrete specimens is well known and can be correctly captured when performing numerical simulations by using a well characterised softening function, but in the case of fibre reinforced concrete this is not directly applicable, since an only diagram cannot capture the material behaviour on elements with different size due to dependence of the orientation factor of the fibres with the size of the specimen. In previous works, the use of a trilinear softening diagram proved to be very convenient for reproducing fracture of polyolefin fibre reinforced concrete elements, but only if it is previously adapted for each specimen size. In this work, a predictive methodology is used to reproduce fracture of polyolefin fibre reinforced concrete specimens of different sizes under three-point bending. Fracture is reproduced by means of a well known embedded cohesive model, with a trilinear softening function that is defined specifically for each specimen size. The fundamental points of these softening functions are defined a priori by using empirical expressions proposed in past works, based on an extensive experimental background. Therefore, the numerical results are obtained in a predictive manner, and then compared with a previous experimental campaign, showing that this approach properly captures the size effect, although some values of the fundamental points in the trilinear diagram could be defined more accurately.
ARTICLE | doi:10.20944/preprints201909.0149.v1
Subject: Materials Science, Biomaterials Keywords: magneto-mechanical actuation; fibre networks; human osteoblasts; mineralization; in vitro osteogenesis
Online: 15 September 2019 (06:13:38 CEST)
There is currently an interest in “active” implantable biomedical devices that include mechanical stimulation as an integral part of their design. This paper reports the experimental use of a porous scaffold made of interconnected networks of slender ferromagnetic ﬁbres that can be actuated in vivo by an external magnetic ﬁeld applying strains to in-growing cells. Such scaffolds have been previously characterized in terms of their mechanical and cellular responses. In this study, it is shown that the shape changes induced in the scaffolds can be used to promote osteogenesis in vitro. In particular, immunofluorescence, gene and protein analyses reveal that the actuated networks exhibit higher mineralization and extracellular matrix production, and express higher levels of osteocalcin, alkaline phosphatase, collagen type 1a1, runt-related transcription factor 2 and bone morphogenetic protein 2 than the static controls at the 3-week time point. The results suggest that the cells filling the inter-fibre spaces are able to sense and react to the magneto-mechanically induced strains facilitating osteogenic differentiation and maturation. This work provides evidence in support of using this approach to stimulate bone ingrowth around a device implanted in bone and can pave the way for further applications in bone tissue engineering.
ARTICLE | doi:10.20944/preprints201809.0160.v1
Subject: Materials Science, General Materials Science Keywords: Sound Absorption Coefficient; Noise; Activated Zeolite; Banana Stem Fibre; Acoustical material
Online: 10 September 2018 (09:32:23 CEST)
The unique porous crystal structure of zeolite offers various important utilizations, it is one of the considerations in selecting zeolite at this study as component of composite for restraining noise. It so happens, previous experiments show that banana stem has porous structure, fibrous, high flexibility and can be applied as material for many various products including as component of acoustic material. The combination of both is alleged that it has capability in absorbing noise. This paper presents an investigation on the composite that it was synthesized of Activated Zeolite and Banana Stem Fibre in various weight for determining its sound absorption coefficient alpha (a). Activating natural zeolite was conducted by using 6M HCl in order for enlarging zeolite pores. The sound absorption coefficient was measured in the frequency range between 125 Hz up to 6000 Hz. The results show that the different weight of banana stem fibre as component of the synthesized composite affects the value of alpha and shifts the frequency area.
ARTICLE | doi:10.20944/preprints202012.0517.v1
Subject: Engineering, Automotive Engineering Keywords: Fatigue; fibre composites; polyester and vinyl ester resins; stress ratio; fatigue model.
Online: 21 December 2020 (12:00:57 CET)
Fatigue loading is critical to fibre reinforced polymer composites due to their anisotropic and heterogenous nature. This study investigated the tensile fatigue behaviour of polyester and vinyl ester based GFRP laminates to understand the critical aspects of failure mode and fatigue life under cyclic loading. GFRP laminates with two different resin systems (polyester and vinyl ester), two different stress ratios (0.1 and 0.5) and two different environmental conditions (air and water) were investigated at an applied stress of 80%, 60% and 40% of the ultimate capacity. Based on the investigated parameters (i.e., resin types, stress ratio, environmental conditioning and maximum applied stress), a fatigue model was proposed. Results show that the resin system plays a great role in fatigue failure mode while the stress ratio and environmental condition significantly affect the tensile fatigue life of GFRP laminates. The types of resin used in GFRP laminates and environmental conditions as input parameter in the proposed fatigue model is a unique contribution.
ARTICLE | doi:10.20944/preprints202009.0697.v1
Subject: Earth Sciences, Atmospheric Science Keywords: UAV; Structure from Motion; photogrammetry; crude protein; acid detergent fibre; hyperspectral sensing
Online: 29 September 2020 (09:07:02 CEST)
The aim of this research was to test recent developments in the use of Remotely Piloted Aircraft Systems or Unmanned Aerial Vehicles (UAV) to map pasture biomass yield and nutrient status, across a selected range of field sites throughout the rangelands of Queensland. Improved pasture management begins with an understanding of the state of the resource base, UAV based methods can potentially achieve this at improved spatial and temporal scales. This study developed predictive models of both pasture yield and pasture nutrient status. An automated pasture height surface modelling technique was developed, tested and used along with field site measurements of pasture yields, to predict further estimates across each field site. Both prior knowledge and automated predictive modelling techniques were employed to predict pasture yield and nutrition. Pasture height surface modelling was assessed against field measurements using a rising plate meter, results reported correlation coefficients (R2) ranging from 0.2 to 0.4 for both woodland and grassland field sites. Accuracy of the predictive modelling was determined from further field measurements of pasture yield and on average indicated an error of 0.8 t ha-1 in grasslands and 1.3 t ha-1 in mixed woodlands across both modelling approaches. Correlation analyses between measures of pasture quality, acid detergent fibre and crude protein (ADF, CP), and spectral reflectance data indicated the visible red (651 nm) and red-edge (759 nm) regions were highly correlated (ADF R2 = 0.9 and CP R2 = 0.5 mean values). These findings agreed with previous studies linking specific absorption features with grass chemical composition. These results conclude that the practical application of such techniques, to efficiently and accurately map pasture yield and quality, is possible at the field site scale, however further research is needed, in particular further field sampling of both yield and nutrient elements across such a diverse landscape, with the potential to scale up to a satellite platform for broader scale monitoring.
ARTICLE | doi:10.20944/preprints201907.0057.v2
Subject: Engineering, Electrical & Electronic Engineering Keywords: birefringence; confinement loss; photonic crystal fibre; relative dispersion slope; single mode operation
Online: 22 April 2020 (05:45:04 CEST)
This article reveals a best possible design for hybrid dispersion compensating fiber (HyDCF) with high birefringence established on modified broadband compensating structure through S, C and L telecommunication bands. The simulation outcome exhibits relatively higher birefringence of 3.76×10-2 at wavelength of 1550 nm. The suggested fiber also has dispersion compensation characteristics in an inclusive series of wavelengths which covers 1400-1625 nm. The reported design can achieve dispersion quantity of – 606 ps/ (nm.km) at 1550 nm effective wavelength. The reported fiber design matches the relative dispersion slope (RDS) 0.003694 nm-1 similar to single mode fiber at 1550 nm operating wavelength. This fiber demonstrates negatively flattened effective dispersion of – 2.703 ± 0.734 ps/ (nm.km) within 180 nm flat band ranging from 1460-1640 nm wavelength. It is also convenient to optical high bit rate communication systems. The low confinement loss is found 3.756×10-10 dB/m at the operating wavelength. This design also achieves highly nonlinear coefficient of 50.34 W-1km-1. In some cases, it can also be used in sensing applications.
ARTICLE | doi:10.20944/preprints202010.0610.v1
Subject: Keywords: Life Cycle Assessment; Bio-based materials; Flax fibre; Climate change; Aviation; Interior fittings
Online: 29 October 2020 (12:23:03 CET)
As part of the efforts to reduce the environmental impacts caused by the aviation sector, the use of bio-based instead of fossil-based materials has been assessed as a possible mitigation option. Natural Fibre Polymer Composites have proven to have a higher environmental performance in the automotive sector and are emerging as an option for weight reduction in aircraft. This study quantifies, though Life Cycle Assessment, the environmental performance of specific flax-based composite panels intended for aircrafts as interior fitting elements (i.e. partition panels, tray tables, baggage compartments) compared to a glass fibre/epoxy composite with a honeycomb core. Through system expansion, the fate of co-products issued from the production of the flax fibre technical textile used as reinforcement in the biocomposite material were considered in the assessment. Results showed that for an application in the aeronautics sector, the weight of the panels is the upmost critical parameter shaping the overall environmental performance of panels. Focusing on the panel production only, the biocomposite panel showed a higher environmental performance in the categories of climate change and marine eutrophication compared to the conventional panel, and the fire suppressant agent was identified as the main contributor to the environmental impacts of the bio-based panel. Yet these gains were negligible when considering the full life cycle of the panels, due to the higher weight (14%) of the bio-based panels; which is linked to the bio-based panel being at a prototype stage.In order to improve the environmental performance of the biocomposite panel and thus reduce its weight, it was shown relevant to optimize geometry of the panel itself, especially its core, so less resin could be used.
ARTICLE | doi:10.20944/preprints202008.0534.v1
Subject: Engineering, Civil Engineering Keywords: jute fibre; reinforcement; modified compaction test; California bearing ratio test; stabilization; shear strength
Online: 25 August 2020 (03:30:40 CEST)
Abstract: This paper is focusing on the stabilisation of soil using jute fibre as soil stabilizer. Stabilisation is the process of modifying the properties of a soil to improve its engineering performance and used it for a variety of engineering works. This study examines the potential of soil stabilization with jute fibre when it is cut into roughly 30mm lengths as stabilizer. The varying percentages like 0.5%, 1%, 1.5 and 2% of pieces of jute fibre were used and mixed it with soil. The laboratory tests such as California Bearing Ratio (CBR) test, modified compaction tests and direct shear strength tests have been conducted to observe the change in engineering properties of soil. On the basis of the experiments performed, it can be concluded that the stabilization of soil using 30mm pieces of jute as stabilizer improves the strength characteristics of the soil so that it becomes usable as one of the reinforcing material for the construction of roadways, parking areas, site development projects, airports and many other situations where sub-soils are not suitable for construction.
ARTICLE | doi:10.20944/preprints201910.0344.v1
Subject: Materials Science, General Materials Science Keywords: banana empty fruit bunch; TiO2/fibre; adsorption; rhodamine B; isotherm and kinetic adsorptions
Online: 30 October 2019 (02:21:11 CET)
Indonesia is one of the largest banana producing countries in the world remaining abundance solid waste of banana fruit bunch. The banana fruit bunch contains high natural fibers which were obtained by an impregnation process using potassium hydroxide (KOH) and followed by a carbonization process under steam at 250°C for 5 h. The nanomaterial of TiO2/fibre was prepared by a hydrothermal process at 200°C for 4 h. Surface morphology proved that the TiO2 was loaded into the fibre by an increasing roughness of the surface and irregular size of porosity. The development of amorphous to crystalline phase of TiO2/fibre was clearly observed. The effectiveness of TiO2/fibre for removal of rhodamine B was investigated from different parameters of adsorptions in aqueous solution. The equilibrium adsorptions show that the Langmuir and Freundlich isotherm exhibited the best correlation coefficient (R2 > 0.94) relating to the chemisorption and physisorption interaction in the adsorption process. Kinetic models were well described by the pseudo-first and second-order with the best correlation coefficient (R2 > 0.99). These results indicate that nanomaterial TiO2/fibre can be used as an effective adsorbent for removal of rhodamine B in aqueous solution.
ARTICLE | doi:10.20944/preprints201909.0180.v1
Subject: Materials Science, Biomaterials Keywords: ferromagnetic fibre network; human albumin; fibrin hydrogel; human foetal osteoblasts; human endothelial cells
Online: 17 September 2019 (04:48:21 CEST)
Porous coatings on prosthetic implants encourage implant fixation. Enhanced fixation may be achieved using a magneto-active porous coating that can deform elastically in vivo on application of an external magnetic field, straining in-growing bone. Such coating, made of 444 ferritic stainless steel fibres, was previously characterised in terms of its mechanical and cellular responses. In this work, co-cultures of human osteoblasts and endothelial cells were seeded into a novel fibrin-based hydrogel embedded in a 444 ferritic stainless steel fibre network. Albumin was successfully incorporated into fibrin hydrogels improving the specific permeability and the diffusion of fluorescently-tagged dextrans without affecting their Young’s modulus. The beneficial effect of albumin was demonstrated by upregulation of osteogenic and angiogenic gene expression. Furthermore, mineralisation, extracellular matrix production and formation of vessel-like structures were enhanced in albumin-enriched fibrin hydrogels compared to fibrin hydrogels. Collectively, the results indicate that the albumin-enriched fibrin hydrogel is a promising bio-matrix for bone tissue engineering and orthopaedic applications.
ARTICLE | doi:10.20944/preprints202210.0458.v1
Subject: Biology, Physiology Keywords: hyperinsulinemia; monosodium glutamate; metabolic syndrome; distress oxidative; pro-inflammatory profile; skeletal muscle fibre types.
Online: 31 October 2022 (01:00:42 CET)
The model of obesity induced by monosodium glutamate cytotoxicity on the hypothalamic nuclei is widely used in the literature. However, MSG promotes persistent muscle changes and there is a significant lack of studies that seek to elucidate the mechanisms by which damage refractory to reversal is established. This study aimed to investigate the early and chronic effects of MSG in-duction of obesity upon systemic and muscular parameters of Wistar rats. Animals were exposed to MSG subcutaneously (4 mg.g-1 b.w.) or saline (1.25 mg.g-1 b.w.) daily from PND01 to PND05 (n = 24). After, in PND15, 12 animals were euthanized to determine the plasma and inflammatory profile and to assess muscle damage. In PND142, the remaining animals were euthanized, and samples for histological and biochemical analyses were obtained. Our results suggest that early exposure to MSG reduced growth, and increased adiposity, induction hyperinsulinemia, and a pro-inflammatory scenario. In adulthood were found, peripheral insulin resistance, reduced muscle mass, oxidative capacity, neuromuscular junctions, increased fibrosis, and oxidative distress. Thus, we can conclude that the condition found in adult life and the difficulty in restoring the muscle profile are related to the metabolic damages established early.
Subject: Engineering, Automotive Engineering Keywords: fracture behaviour; fibre reinforced concrete; high temperature; melting point; flexural tensile strength; polyolefin fibres
Online: 7 December 2020 (12:05:10 CET)
Concrete has become the most common construction material showing among other advantages good behaviour when subjected to high temperatures. Nevertheless, concrete is usually reinforced with elements of other materials such as steel in the form of rebars or fibres. Thus, the behaviour under high temperatures of these other materials can be critical for structural elements. In addition, concrete spalling occurs when concrete is subjected to high temperature due to internal pressures. Micro polypropylene fibres (PP) have shown to be effective for reducing such spalling although this type of fibres barely improve any of the mechanical properties of the element. Hence, a combination of PP with steel rebars or fibres can be effective for the structural design of elements exposed to high temperatures. New polyolefin fibres (PF) have become an alternative to steel fibres. PF meet the requirements of the standards to consider the contributions of the fibres in the structural design. However, there is a lack of evidence about the behaviour of PF and elements made of polyolefin fibre reinforced concrete (PFRC) subjected to high temperatures. Given that these polymer fibres would be melt above 250 °C, the behaviour in the intermediate temperatures was assessed in this study. Uni-axial tests on individual fibres and three-point bending tests of PFRC specimens were performed. The results have shown that the residual load-bearing capacity of the material is gradually lost up to 200 °C, though the PFRC showed structural performance up to 185°C.
REVIEW | doi:10.20944/preprints201810.0147.v1
Subject: Engineering, Civil Engineering Keywords: alternative materials, fibre reinforced polymer, insulation, precast concrete sandwich panel, shear connection, thermal efficiency
Online: 8 October 2018 (12:50:05 CEST)
Precast concrete sandwich panels (PCSP) are energy efficient building system that is achieved through an insulation layer created between the concrete wythes. The insulation layer is usually of low bearing strength material making it more applicable for non-structural building systems. Hence, shear connectors are introduced to improve its structural capacity, which subsequently degrades it thermal performance by serving as thermal bridges across the panel. This article review researches of alternative materials and methods used to improve the thermal efficiency as well as reduced the strength loss due to insulation in PCSP. The alternative materials are basalt fibre reinforced polymer (BFRP), carbon fibre reinforced polymer (CFRP), glass fibre reinforced polymer (GFRP), and foam concrete which are selected due to their low thermal conductivity for use in shear connection. While thermal path method has been used to prevent the effect of thermal bridges. Although, some of these materials have successfully achieved the desirable behaviours, however, several undesirable properties such as brittleness, bond slip, the sudden crushing of the panel system, and FRP failure below its ultimate strength were observed. Hence, the practicality of the alternative materials is still questionable despite its higher cost compared to the conventional steel and concrete used in the PCSP system.
ARTICLE | doi:10.20944/preprints201711.0055.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: diet; dietary protein; dietary fibre; insulin sensitivity assessment; insulin sensitivity; insulin resistance; metabolic syndrome
Online: 8 November 2017 (16:20:47 CET)
Evidence shows that weightloss improves insulin sensitivity but few studies have examined the effect of macronutrient composition independently of weight loss on direct measures of insulin sensitivity. We randomised 89 overweight or obese women to either a standard diet (StdD) that was intended to be low in fat and relatively high in carbohydrate (n=42) or to a relatively high protein (up to 30% of energy), relatively high fibre (>30g/day) diet (HPHFib) (n=47) for 10 weeks. Advice regarding strict adherence to energy intake goals was not given. Insulin sensitivity and secretion was assessed by a novel method - the Dynamic Insulin Sensitivity and Secretion Test (DISST). Although there were significant improvements in body composition and most cardiometabolic risk factors on HPHFib, insulin sensitivity was reduced by 19.3% (95% CI: 31.8, 4.5%; p=0.013) in comparison with StdD. We conclude that the reduction in insulin sensitivity after a diet relatively high in both protein and fibre, despite cardiometabolic improvements, suggests insulin sensitivity may reflect metabolic adaptations to dietary composition for maintenance of glucose homeostasis, rather than impaired metabolism.
ARTICLE | doi:10.20944/preprints202008.0413.v1
Subject: Engineering, Civil Engineering Keywords: Concrete quality; concrete additive; cross-section; concrete mixture; concrete composition; plastic waste; HDPE; plastic fibre
Online: 19 August 2020 (10:56:00 CEST)
HDPE (high-density polyethene) plastic waste is stronger, harder, and more resistant to high temperatures than other plastics. Using it as an additive in a concrete mixture is one solution to reduce this type of waste. We examined how HDPE-type plastics can be used as an additive material in the manufacture of concrete to improve its hardness, tensile strength and compressive strength. Using 156 samples, we aimed to identify the effect of HDPE plastic fibres on concrete of three qualities; B0, f'c10 MPa (low quality), and f'c25 MPa (medium and high quality). We added four compositions (2.5%, 5%, 10% and 20% by weight of cement) of HDPE plastic fibre to each quality of cement, with HDPE plastic fibre sizes of 1 x 1 cm, 0.5 x 2 cm or 0.25 x 4 cm. We found that the addition of 5% HDPE plastic fibre with a 0.5 x 2 cm cross-sectional shape to the f'c10 MPa concrete gives the best result, with increased tensile and compressive strength of the concrete.
ARTICLE | doi:10.20944/preprints201809.0544.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: Bodybuilding; Drug Free; Competing; Peaking; Carbohydrate Loading; Water Loading; Sodium Loading; Fat Loading: Vitamin C; Fibre Restriction
Online: 27 September 2018 (12:58:34 CEST)
Bodybuilders utilize peaking strategies in a bid to fine-tune their aesthetics for competition day. The most prevalent peaking strategies utilized by natural bodybuilders are unreported in the current literature. Eighty-one (M - 59, F - 22) natural bodybuilders were recruited from competitions during the 2016 and 2017 British Natural Bodybuilder Federation seasons. Competitors completed a 34-item questionnaire designed to investigate peaking and contest day strategies. The questionnaire listed commonly utilized peaking strategies and provided additional space for qualitative information. Analysis of the data indicated that carbohydrate (CHO), water and sodium manipulation were the most commonly utilized peak week strategies. The consumption of high glycemic index CHO was the most common competition day strategy. Only 6.2 % of competitors reported following their regular diet the week prior to competition. The CHO manipulation strategies were similar to classical CHO loading, whereby bodybuilders attempt to maximize muscle glycogen concentrations. Furthermore, bodybuilders attempted to remove superfluous water by exploiting the diuretic/polyuria effect associated with water loading/restriction. The potentially deleterious effects of peaking on bodybuilders' health is considered and the efficacy of these strategies to enhance appearance is discussed. The findings of the present investigation are likely to be of interest to bodybuilders and their coaches.
ARTICLE | doi:10.20944/preprints201903.0161.v1
Subject: Engineering, Civil Engineering Keywords: Response Surface Methodology; Hybrid; Genetic Algorithm Artificial Neural Network; Concrete; Flexural Strength; Steel Fibre Reinforced Concrete; Civil Engineering
Online: 15 March 2019 (09:54:22 CET)
The study presents a comparative approach between response surface methodology (RSM) and hybridized, genetic algorithm artificial neural network (GA-ANN) in predicting the water absorption, compressive strength, flexural strength split tensile strength and slump for steel fiber reinforced concrete. The effect of process variables such as aspect ratio, water cement ratio and cement content were investigated using the central composite design of response surface methodology. This same experimental design was used in training the hybrid-training approach of artificial neural network. The predicting ability of both methodologies were compared using the root mean sqaured error (RMSE), mean absolute error (MAE), model predictive error (MPE) and absolute average deviation (AAD). The RSM model was found more accurate in prediction compared to hybrid GA-ANN.
ARTICLE | doi:10.20944/preprints202210.0017.v1
Subject: Engineering, Civil Engineering Keywords: beam-column joint; fibre-based section modeling; joint shear hinge; substandard beam-column joints; stiffness and strength deterioration; reinforced concrete; seismic vulnerability; risk
Online: 4 October 2022 (10:38:02 CEST)
The paper discusses how joint damage and deterioration affect the seismic response of existing reinforced concrete frames with sub-standard beam-column joints. The available simplified modeling techniques are critically reviewed to propose a robust, yet computationally efficient technique for simulating the nonlinear behavior of substandard beam-column joints. Improvements over the existing models include simulation of the cyclic deterioration of joint stiffness and strength as well as pinching in the hysteretic response, implemented considering a deteriorating hysteretic rule. A fibre-section forced-based inelastic beam-column element is developed; considering improved material models and fixed-end rotation due to bond failure, rebars-slip and inelastic extension, to simulate the deteriorating cyclic behavior of existing pre-cracked beam-column members. For the assessment of frames with substandard exterior beam-column joints, a nonlinear model for the exterior joint is developed and validated through a full-scale quasi-static cyclic test performed on a substandard T-joint connection. The proposed model allows considering structural performance in risk assessment while accounting for true inelastic mechanisms at the joints.
REVIEW | doi:10.20944/preprints201703.0093.v1
Subject: Medicine & Pharmacology, Gastroenterology Keywords: lifestyle factors; chronic inflammatory diseases; treatment result; treatment response; diet; meat intake; dietary pattern; food; mucosa associated bacteria; epithelium-associated bacteria; microbiome; fibre intake; personalized medicine; mucus; sulphate-reducing bacteria; mucin-degrading bacteria; Western style diet; anti-TNF
Online: 15 March 2017 (07:29:13 CET)
We wanted to investigate the current knowledge on the impact of diet on anti-TNF response in inflammatory bowel diseases (IBD), to identify dietary factors that warrant further investigations in relation to anti-TNF treatment response, and, finally, to discuss potential strategies for such investigations. PubMed was searched using specified search terms. One small prospective study on diet and anti-TNF treatment in 56 patients with CD found similar remission rates after 56 weeks among 32 patients with good compliance that received concomitant enteral nutrition and 24 with poor compliance that had no dietary restrictions (78% versus 67%, p = 0.51). A meta-analysis of 295 patients found higher odds of achieving clinical remission and remaining in clinical remission among patients on combination therapy with specialised enteral nutrition and Infliximab (IFX) compared with IFX monotherapy (OR 2.73; 95% CI: 1.73–4.31, p < 0.01, OR 2.93; 95% CI: 1.66–5.17, p < 0.01, respectively). In conclusion, evidence-based knowledge on impact of diet on anti-TNF treatment response for clinical use is scarce. Here we propose a mechanism by which Western style diet high in meat and low in fibre may promote colonic inflammation and potentially impact treatment response to anti-TNF drugs. Further studies using hypothesis-driven and data-driven strategies in observational, animal and interventional studies are warranted.