Bamboo Rings Research Articles

Moisture ageing effects on the mechanical performance of eco-friendly sandwich panels made of aluminium skins, bamboo ring core and bio-based adhesives

Recent research has been focused on developing high-performance sandwich structures using renewable resources. The adoption of bamboo rings as a core material and bio-based adhesives has emerged as a promising sustainable design solution for panel construction. It is therefore critical to conduct accelerated ageing tests on these materials to evaluate the impact of environmental humidity on their degradation and durability. This study assessed the effects of moisture ageing on the physic-mechanical properties of eco-friendly sandwich panels and their constituents (aluminium skins, bamboo ring core and castor oil bio-adhesive). Mechanical evaluations of sandwich panels with compacted and spaced bamboo ring cores were performed under varying humidity conditions. Bamboo rings exhibited variable bulk density due to swelling and loss of organic material over time. They also demonstrated increased compressive properties after 2 years of natural ageing but reduced performance after 30 days at 100% relative humidity. The mechanical properties of the bio-based polymer were enhanced through water-ageing exposure. Sandwich panels constructed with compacted bamboo ring cores exhibited higher bending properties than those with spaced ring core architecture, with the latter showing failures characterised by a wrinkling effect on both skins followed by debonding.

Differences in dry shrinkage of bamboo rings with multiple heights and radians based on vascular bundle group

Abstract Moso bamboo is widely used in production due to its high strength-to-weight ratio, fast growth and renewability. Meanwhile, bamboo’s dimension is highly sensitive to moisture, resulting in cracking and other defects easily. This study aimed to investigate the changes in cracks, bamboo ring shapes, fiber sheath area and volume fraction, and vascular bundle group shapes from the green state to the absolute-dry state, using the target detection model and Python fitting technique. The results showed that the radius of the vascular bundle group increased while its radian and arc length decreased with a decrease in the moisture content. The decrease in the cross-sectional area was greater than that in the wall thickness and arc length. The dry shrinkage of the fibers was greater than that of the rest tissues, which was an important part of the shrinkage of bamboo rings. Obvious cracks mainly appeared in the bamboo ring with a complete radian of 2π, while almost no or very limited cracks were seen in other rings with incomplete radians. This study further elaborated on the dry shrinkage changes and differences in bamboo rings, which might be beneficial to restrain the deformation and cracking of bamboo products effectively.

An investigation on the mechanical behaviour of sandwich composite structures with circular honeycomb bamboo core

Sandwich panels made with a bamboo core of different dimensions, packing geometries and facing materials are subjected to three-point bending tests and assessed through statistical and failure analysis. In addition to promoting a circular economy, this architecture holds great promise for replacing secondary structural components in sustainable construction and transportation facilities. The statistical analysis responses are associated with the equivalent density of the panels, flexural strength and modulus of the panels, skin stress and core shear strength and modulus. Individual bamboo rings are also characterised using physic mechanical and interfacial bonding tests. Treated aluminium face sheets provide the best mechanical performance compared to glass fibre-reinforced composite (GFRP) ones by increasing the overall properties of the sandwich panels. The specific face sheet material and void percentage affect the equivalent density, with lower values (~ 0.48 g/cm3) when using GFRP skins, larger bamboo rings and cubic packing. Sandwich panels with 30 mm bamboo rings and hexagonal packing provide higher flexural properties, i.e. ~ 43 MPa strength and ~ 7.6 GPa modulus, and skin stress (~ 288 MPa), while those with 20 mm bamboo rings have higher shear stiffness (~ 132 MPa) and resistance (~ 3.33 MPa). Sandwich panels made with aluminium skins show evident skin-polymer debonding, while those with GFRP have premature skin failure and lower structural performance. The proposed sandwich panels present remarkable and competitive mechanical performance concerning commercial analogous structures, generally used in the aeronautical and automotive industries.

Intelligent analysis technology of bamboo structure. Part II: The variability of radial distribution of fiber volume fraction

Scientific and reasonable utilization of bamboo is strongly related to the radial distribution of the fiber volume fraction. In this paper, the K-means clustering algorithm was applied to set separate thresholds for individual vascular bundles, to solve the problem that the bamboo ring cannot be binarized well. We introduced a layered model based on the WEB coordinate system, programmed via JavaScript, to layer the cross-section within the entire bamboo conveniently and accurately. It allowed uniform layering of sample areas of any thickness, any width, and any number of layers. Furthermore, this research systematically studied the bamboo rings at the breast height of Moso bamboo [Phyllostachys edulis (Carr)H. de Lebaie] grown in 12 major producing areas of China and the 50-internode sections from base to top of one bamboo with the method mentioned above. The results indicated that the thickness of a single layer should not be higher than 0.4 mm while examining the gradient structure of bamboo. The radial distribution of fiber volume fraction from 12 areas all followed the ExpDec1 function, and the mean goodness of fit (R2) was 0.988. The radial distribution of fiber volume fraction in the first 45 sections from the base to the top corresponded to the ExpDec1 function. It provided a theoretical basis for the functional improvement of bamboo and the development of new bamboo-based smart materials.

Sustainable Sandwich Panels Made of Aluminium Skins and Bamboo Rings

This work investigates the mechanical behaviour of a sustainable sandwich panel, consisting of bamboo rings core, treated aluminium skins and epoxy adhesive. A Design of Experiment (DoE) is used to identify the effects of bamboo diameters (30 and 45 mm) and aluminium skin treatments (alkaline degreasing and application of primer) on the mechanical and physical properties of sandwich panels. The aluminium skins treated with the wash primer significantly increase adhesion to the polymer, resulting in greater maximum load, flexural strength, maximum skin stress and maximum core shear stress; while the skins treated with NaOH resulted in a greater flexural and core shear modulus. Relatively more rigid and resistant structures are obtained with Ø30 mm rings, due to the increased surface contact area and the number of constraints on the core. The samples fail due to the skin fracture, implying an efficient face-core bond that is attributed to the proper absorption of the polymer by bamboo and the treatment of the aluminium surface. The proposed panels present good mechanical performance, proving to be a feasible and promising alternative for secondary structural applications.

Indentation Coefficient and Indentation Behavior of Bamboo

Bamboo hardness test standards are not available. The study aimed to develop a new method of testing bamboo indentation hardness. With the V-shaped prismatic head, bamboo rings with different lengths were tested. The V-shaped indentation coefficient (IC) was defined. The results showed that the IC had a good correlation with compression strength. The V-shaped IC increased with the increase in the longitudinal height of the bamboo pole, and the variance analysis showed significant differences in different axial directions of the same bamboo ring. In addition, the correlation between density and IC is good. The V-shaped IC can be applied in bamboo gra

A novel sandwich panel made of prepreg flax skins and bamboo core

This work describes the bending and shear mechanical properties of a novel concept of sustainable sandwich panel made from unidirectional prepreg flaxtape skins and bamboo rings as a circular core material. A Design of Experiment (DoE) is used to determine the influence of the bamboo diameter and the type of adhesive bonding between core and skins on the equivalent density, flexural and shear properties of these panels. Numerical analysis are also performed using cohesive surface contacts between skins and bamboo rings to investigate the structural behaviour and failure mechanisms of the sandwich panels. The equivalent density is affected by both factors, with an overall decrease when larger bamboo rings and lower density adhesive are used. Although sandwich panels with the larger bamboo rings as core show superior flexural properties and skin stress, smaller bamboo rings cores shows an increase in the core transverse shear modulus. The physical and mechanical characteristics of the adhesives directly affect the failure mode and the overall structural integrity of the panels.

Experimental study on bending and shear behaviours of composite timber sandwich panels

Composite sandwich panels were manufactured by gluing plywood skins to either bamboo rings to produce Bamboo Core Sandwich (BCS) panels or to peeler core rings to produce Peeler Core Sandwich (PCS) panels. Single and double core layer panels were made. The optimum adhesive spread rate was identified through conducting shear bond tests. The manufactured panels were physically tested in standard bending (using four-point) and shear (using three-point) tests. Results were compared to the test results of conventional Cross-laminated Timber (CLT) panels with almost similar depth. Under bending action, both the BCS and PCS panels showed tensile failure in the plywood, while the plywood in compression exceeded its plastic limit at the ultimate load. In shear, BCS panels failed due to the loss of shear interface contact between bamboo core rings and the plywood skins, whereas PCS panels showed local indentation/bond failure between the peeler core rings and the plywood skins. No significant improvements were observed in the double-layer panels compared to single-layer panels in bending. However, in shear, double-layer panels showed more consistent capacities. One PCS panel with thicker plywood skins and less peeler core rings (PCS-TH) was manufactured, and was shown to achieve 0.77 times the bending stiffness-to-weight ratio of the commercial CLT panel. Reduced weight, lower material costs, ease of manufacturing and usage of sustainable/waste products, make the proposed sandwich panels a potential alternative for CLT in terms of structural performance. Moreover, the proposed peeler core sandwich panels displayed better ductile performances in bending and shear compared to CLT suggesting it could be a preferred product choice in some building applications.

Enhanced charge generation and transfer performance of the conical bamboo-like TiO2 nanotube arrays photo-electrodes in quantum dot sensitized solar cells

Conical bamboo-like TiO2 nanotubes (NTs) electrodes, instead of the traditional TiO2 NTs and conical TiO2 NTs electrodes, are employed as the photo-electrodes for the fabrication of CuInS2 quantum dot sensitized solar cells (QDSSCs), which have improved deposition content of QDs in solar cells. The distances between each bamboo ring are modulated by the different anodization holding times. In addition, the optical properties of different TiO2 NTs electrodes and CuInS2 quantum dots sensitized photo-electrodes are investigated, which reveals that the deposition content of QDs have been improved by the bamboo rings of conical bamboo-like TiO2 NTs based photo-electrodes to obtain better optical absorption property and charge separation property. More importantly, the bamboo rings in the conical bamboo-like TiO2 NTs structure can provide more paths for the charge transfer, which results in improved charge transfer rate in the QDSSCs. Finally, the optimized conical bamboo-like TiO2 NTs prepared by anodization holding time of 20 min exhibits higher current density, which leads to a significant increasing of the photovoltaic conversion efficiency from 4.65% to 5.98%.

Impact of carrier on ammonia and organics removal from zero-discharge marine recirculating aquaculture system with sequencing batch biofilm reactor (SBBR).

Marine recirculating aquaculture system (MRAS) is an effective technology that provides sustainable farming of food fish globally. However, dissolved organics material (chemical oxygen demand, COD) and especially ammonia are produced from uneaten feed and metabolic wastes of fish. To purify the MRAS water, this study adopted a sequencing biofilm batch reactor (SBBR) and comparatively investigated the performances of four different carriers on ammonia and COD removal. Results indicated that the NH4+-N removal rates were 0.045 ± 0.05, 0.065 ± 0.008, 0.089 ± 0.005, and 0.093 ± 0.003 kg/(m3·d), and the COD removal rates were 0.019 ± 0.010, 0.213 ± 0.010, 0.255 ± 0.015, and 0.322 ± 0.010 kg/(m3·d) in the SBBRs packed with porous plastic, bamboo ring, maifan stone, and ceramsite carriers, respectively. Among the four carriers, ceramsite exhibited the best performance for both NH4+-N (80%) and COD (33%) removal after the SBBR reached the steady-state operation conditions. For all carriers studied, the NH4+-N removal kinetics could be well simulated by the first-order model, and the NH4+-N and COD removal rates were logarithmically correlated with the carrier's specific surface area. Due to its high ammonia removal, stable performance and easy operation, the ceramsite-packed SBBR is feasible for MRAS water treatment.

Cassava Wastewater Treatment in Fixed-Bed Reactors: Organic Matter Removal and Biogas Production

The process of cassava starch extraction is associated with the generation of a large volume of liquid wastes from root washing and starch extraction (5 to 7 L.kg-1root). In this context, the objective of this study was to evaluate the treatment of cassava starch wastewater in a horizontal anaerobic fixed bed reactor to the removal of organic matter and generation of biogas. For this purpose, two fixed bed reactors filled with two different types of support materials were used: bamboo rings and flexible PVC rings. The reactors were constructed in polyvinyl chloride (PVC) with 90 cm length and 15 cm diameter. The working volume of R1 (bamboo as support material) and R2 (PVC as support material) were 6.0 and 8.0 L, respectively. In the operation of the reactors, 13 assays (A1 to A13) were carried out with an increase in the organic loading rate (OLR: 1.7 to 15.0 g COD.L-1.d-1) and a decrease in the hydraulic retention time (HRT: 4.0 to 0.8 days). Biogas production followed a similar pattern in both reactors. The highest biogas productions of 1.5 L.L-1.d-1 (R1) and 1.1 L.L-1.d-1 (R2) were verified in the assay 6 in which were applied highest affluent concentration (15,122 mg.L-1), intermediates organic loading rate (5.6 g.L-1.d-1) and hydraulic retention time (2.7 d). The removal of COD increased with the increase of OLR resulting in COD removal values of up to 99%. Total solids removal efficiencies of 79 and 87% were achieved in R1 and R2, respectively. In both reactors, the contact surface of bamboo (132 m2.m-3) and PVC (191 m2.m-3) supported biomass attachment even in highest OLR (15 g.L-1.d-1) and low HRT (0.8 d). The both support material provided conditions to the reactors withstand the variations and reestablish the equilibrium after possible hydraulic and load shocks, constituting a robust system for the treatment of cassava starch wastewater. In these conditions the COD and solids removal remained satisfactory. After a 450-day reactor running, no changes were observed in the composition and structure of the support material, an indication that bamboo and PVC are possible cheap and efficient alternatives for biomass immobilization.

An investigation on the unevenness, hairiness and friction coefficient properties of cotton-bamboo blended ring-spun yarns

This study aims to investigate the frictional and other important yarn properties such as unevenness and hairiness of cotton/bamboo blended yarns. For this purpose, %100 cotton, %50/%50 cotton/bamboo and %100 bamboo ring spun yarns were produced in five different twist coefficients (ae: 3.5; 3.7; 4.0; 4.2; 4.5) and in four different linear densities (Ne 16/1; 20/1; 24/1; 28/1). General factorial design was used for analyzing the data. In conclusion, the highest friction coefficient and the lowest hairiness were obtained for the pure bamboo blends; whereas, the highest unevenness values were observed in pure cotton

Electrochemically Faceted Bamboo‐type TiO2 Nanotubes Provide Enhanced Open‐Circuit Hydrogen Evolution

AbstractIn this paper we prepare facetted “black” TiO2 nanotube arrays (NTAs) with a bamboo‐type structure which exhibits an enhanced performance for open‐circuit H2 generation without the use of any noble metal co‐catalyst. The TiO2 nanotubes were formed by applying alternating positive and negative voltages. During the electrochemical formation, not only a bamboo structure is formed but the tubes are reduced in the cathodic cycle. After a rapid annealing treatment of these tubes in air at 500 °C for 10 s, the bamboo rings (knots) provide (001) facets preferentially located at the knot, while (101) planes prevail on the smooth part of tube between knots, as shown by TEM. The short annealing time keeps Ti3+/oxygen vacancies (VO) as co‐catalytically active centers still preserved in the TiO2 NTAs. The results of intensity modulated photocurrent spectroscopy (IMPS) and open‐circuit potential decay measurements (VOC) indicate that these faceted and reduced TiO2 nanotube arrays provide an efficient separation and reaction of photo‐generated charge carriers, leading to an improved photocatalytic H2 evolution performance.

Slaughterhouse wastewater treatment in a bamboo ring anaerobic fixed-bed reactor

Slaughterhouse wastewater treatment in a bamboo ring anaerobic fixed-bed reactor

Start-up of anaerobic reactors for slaughterhouse wastewater treatment

This study aimed to evaluate the start-up of a horizontal anaerobic fixed bed reactor (HAFBR) followed by an upflow anaerobic sludge blanket (UASB) for the slaughterhouse wastewater treatment. HAFBR was filled with bamboo rings and had 1.2 m in length, 0.10 m in diameter and volume of 7.5 L. The UASB had the volume of 15 L. The HAFBR and UASB operated at organic loading rate and hydraulic retention time average of 8.46 and 3.77 kg m-3 d-1 of COD and 0.53 and 0.98 days, respectively. During 150 days of monitoring system it was found pH 6.8, relatively high values of bicarbonate alkalinity (> 1000 mg L-1) and reduced values of volatile acids (70 to 150 mg L-1), which afforded average removal efficiencies of COD total and total suspended solids of the order of 31 and 23% in HAFBR and 79% and 63% in UASB. It can be concluded that the generation and consumption of bicarbonate alkalinity and total volatile acids, thereby maintaining the pH during the study indicated stable operation of the reactors. The COD removal in the reactors was satisfactory especially when it considers that the assessment was conducted in a period of adaptation of organisms to the effluent and also the high organic load applied during this period.

Technical and economic viability of a compact, partially submersed black water treatment system for floating residences

Riverine populations in the Amazon lack appropriate sanitation technologies due to the challenges imposed by the várzea (floodplain) environment. This compromises their health and the quality of the environment in which they live. This study aims to verify the technical and economic viability of a black water treatment using a septic tank + anaerobic filter (bamboo rings, crushed stone, brick fragments) with locally available components, of small volume and which is partially submersed. The system's pollutant removal efficiency was considered using analyses of pH, temperature, biochemical oxygen demand (BOD), chemical oxygen demand (COD), nitrogen, ammonium and phosphorus. Economic viability was calculated using the costs of the systems, compared with the value of a standard residence and family income of residents of the Mamirauá and Amanã Reserves. BOD removal efficiency was similar for the media filter tested (average 77%). COD load removal was between 67 and 83%. Nitrogen and phosphorus concentrations remained high in relation to legal standards, with 59 and 96 mg L−1 of phosphorus for the brick fragment filters, and 230 and 379 mg L−1 of nitrogen for the crushed stone and bamboo ring filters, respectively. The cost for the system was US$ 1,000, about 5% of the cost of a standard residence. The three filter configurations were similar in terms of organic material removal. The technology proved viable in terms of efficiency and cost as it is an accessible option for the várzea environment.

A Woman and Collectives: An Interview with Tabe Mitsuko

Tabe Mitsuko (b. 1933) was one of the principal members of Kyūshū-ha (Kyūshū school), an avant-garde artist collective that was founded in Fukuoka in 1957 and lasted until about 1970. Tabe's early paintings, such as Anger of Fish Tribes (Gyozoku no Ikari, 1957), using asphalt and bamboo rings, reflect Tabe's concern about industrial pollution. While their thick texture followed the signature Kyūshū-ha style, Tabe's works often stood out for expressing strong social consciousness, including proto-feminist concerns in the early 1960s. During her pregnancy, she created a mixed-media installation titled Artificial Placenta (Jinkō Taiban, 1961), which consisted of three mannequin hips propped upside down on pedestals, each hip containing a radio vacuum tube in its opening. While Tabe's art developed with Kyūshū-ha, her career has long outlived it. This interview sheds light onto Tabe's experience as a woman artist in the male-dominant avant-garde environment in the southern region of Kyūshū from the mid-1950s to the 1980s. Gender and sociopolitical dynamics in various art collectives are the primary focus throughout the interview in order to reveal the less examined inner workings of these groups through an artist's recollection.

Highly-ordered TiO2 nanotube arrays with double-walled and bamboo-type structures in dye-sensitized solar cells

Dye-sensitized solar cells (DSSCs) based on free-standing, double-walled TiO2 nanotubes with bamboo-like morphology have been prepared by a sequence of alternating voltage and two-step anodization treatments. The combination of double-walled and bamboo-like morphologies led to an increase in dye loading and an improvement in photoconversion performance. Subsequently, the fabricated dye-sensitized nanotubes used to prepare DSSCs that operate in a frontside illumination mode yielded a significantly high power conversion efficiency of 3.46%, which was approximately two times higher than DSSCs that were fabricated using traditional single-walled TiO2 nanotube arrays with smooth surfaces. In addition, DSSCs fabricated from nanotubes with higher bamboo ring densities exhibited better conversion efficiencies than those prepared from nanotubes with lower bamboo ring densities. The improved conversion efficiency can be attributed to increased dye loading in the combined double-walled and bamboo-like titania nanostructures.

THE CIRCUMFERENTIAL MECHANICAL PROPERTIES OF BAMBOO WITH UNIAXIAL AND BIAXIAL COMPRESSION TESTS

The objective of this study was to investigate the effect of uniaxial and biaxial compression loadings on the circumferential-radial mechanical properties of bamboo. A novel biaxial testing device, called the 3D composite material analysis system, was developed to conduct biaxial compression tests. Strain field analysis was characterized with the help of the digital speckle correlation method (DSCM). The effects of four different environmental treatments (I. air-drying, II. constant temperature and relative humidity, III. relatively low temperature, and IV. ultra-low temperature) on the circumferential performance of bamboo were examined in the experiment. The results of this study indicated that the diametric strength of bamboo evaluated by biaxial load was as 2.4 to 2.5 times the uniaxial compression. Under biaxial load, the strength of the bamboo node was about 2.38 times higher than the internode. Failure first occurred at the outside surface of bamboo at about the 45° position between X and Y axial when conducting a biaxial compression test. The distribution of X-strain field expressed itself more uniformly than the Y-strain field. The diametric mechanical properties of bamboo ring were σIV>σIII>σII>σI for both the uniaixal and biaxial compression tests.

Using a sustainable material to produce a sound absorbing panel.

A recent university research project involved the creation of an environmentally friendly sound absorbing panel using bamboo. The goal of this research was to produce a panel with a sustainable material that could be used in similar applications where wood fiber sound absorbing panels would be employed. The test bamboo panel has been made from bamboo rings approximately 1.6 mm thick cut from bamboo stalks with diameters varying from approximately 6 to 50 mm. The bamboo rings were randomly formed into a panel about 25 mm thick using an environmentally friendly adhesive with very low viscosity. Panel sound absorption has been determined using the reverberation room method, an in situ method, and an impedance tube method. [This research was partially funded by an Acoustical Society Robert W. Young award.]