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Influence of Blueberry and Jaboticaba Agroindustrial Residue Particle Size on Color Change of Corn Starch Based Films Submitted to Different pH Values Solutions
No full textCorn starch, glycerol and agroindustrial residues were used to produce films by casting. By-products from juice processing, blueberry and jaboticaba in powder with different particle sizes were added in the filmogenic matrix to evaluate its potential as a colorimetric indicator. Blueberry and jaboticaba peels are commonly discarded although contain high amount of important compounds as anthocyanins. These compounds have the ability to color change after immersion in different pH values, demonstrating its potential for the intelligent packaging development. Analyses were performed in a colorimeter after films immersion in different buffer solutions. Visual color changes were perceived; reddish and bluish color in acidic and basic pH values, respectively. Independently of the particle size, the ΔE* values were greater than 5, showing visually perceptible change to the human eye. The results indicate the potential of use of these residues as a pH indicator for the development of renewable and biodegradable sensor of food deterioration
Performance Comparison of Chemically Modified Sugarcane Bagasse for Removing Cd(II) in Water Environment
No full textThis paper evaluates the adsorption capacity of chemically sugarcane bagasses with sodium hydroxide (SHS), citric acid (CAS), tartaric acid (TAS) and unmodified sugarcane bagasse (SB) for cadmium adsorption in water environment. The results prove adsorption capacity for Cd (II) increases after chemical modification and the adsorption fits perfectly with the Langmuir isotherm. CAS had the highest maximum adsorption capacity of 45.45 mg/g followed by TAS with 38.46 mg/g and SHS with 29.41 at optimum pH 5.0 and 120 minutes equilibrium time while 1 g SB removed 18.8 mg Cd (II) in the same conditions. The kinetics study of the process followed a pseudo-secondorder rate expression, that indicated a strong interaction between the biosorbents and adsorbate. The sugarcane bagasse and modified sugarcane bagasse were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis. The chemical modification was confirmed by the presence of carboxyl and esters groups created at 1,738 cm-1. The estimation of acid groups in modified materials shows the enhancement of this group after modification. On the other hand, desorption studies showed the high leaching of cadmium ion from the biosorbent leading to the efficient reutilization of materials
Application of Modern Wood Product Glulam in Timber Frame With Tenon-Mortise Joints and Its Structural Behavior
No full textTenon-mortise joint is widely used in traditional timber structures around the world. This paper summarizes the results of an experimental study of the structural behavior of tenon-mortise joints made with glulam and CNC technology instead of traditional material and manual work. 30 full-scale tenon-mortise joints were manufactured and tested under monotonic loading, and the effects of dimension, shape, processing error and adhesive were evaluated. It was found that the round rectangular shaped tenon-mortise joints were comparable with traditional joints in terms of structural performance, but were time and labor saving. The variability of the proposed tenon-mortise joints was lower, which would benefit the design value. Applying adhesive between tenon and mortise increased the average stiffness by 4.3 times and average moment capacity by 27.4%, respectively. The gaps between wood members had little effect on the capacity and stiffness in monotonic bending but may influence the energy dissipation ability in cyclic bending. This study showed the feasibility of combining the traditional joinery method with modern wood products and manufacturing technology, which may promote the application of tenon-mortise joints in modern timber structures
Compression Behaviors of Parallel Bamboo Strand Lumber Under Static Loading
No full textIn order to investigate the influence of length and compression directions upon behaviour of parallel bamboo strand lumber (PBSL) specimens, 240 axial compression tests have been performed. With three similar one different typical failure modes, the mechanical performance for PBSL specimens under compression parallel to grain and perpendicular to grain are different as a whole. From the point of the characteristic values, the compression strength parallel to grain is 2.1 times of the compression strength perpendicular to grain. The elastic modulus for compression parallel to grain is 3.64 times of the compression strength perpendicular to grain. While the compression ratios along two compression directions are equal to each other. The bigger Poisson ratios for one typical side surface is 3.93 times of that for another typical side surface for PBSL specimens under compression perpendicular to grain, and the bigger value is equal to that for PBSL specimens under compression parallel to grain. Length can influence the mechanical properties of the PBSL specimens. The size 50 mm × 50 mm × 100 mm should be good choice for the standard or code to measure the compression strength. PBSL materials have better ductility under compression parallel to grain than that under compression perpendicular to grain. Stress-strain relationship models were proposed for PBSL specimens under compression parallel to grain and perpendicular to grain, respectively. These proposed models gave a good agreement with the test results
Preparation of Antibacterial Cotton Wound Dressing By Green Synthesis Silver Nanoparticles Using Mullein Leaves Extract
No full textSilver nanoparticles (AgNPs) were synthesized by a bio-reduction method using an aqueous extract of mullein leaves (Verbascum thapsus L.) functioning as reducing as well as a stabilizing agent. Various synthesis parameters such as reaction time, temperature and concentration of the extract were also studied for the synthesis of AgNPs. The so prepared AgNPs were characterized by various techniques including UV-Vis spectroscopy, X-ray diffraction, scanning electron microscopy (equipped with energy dispersive analysis of X-rays), and transmission electron microscopy. The electron microscopy images suggest the formation of polydispersed spherical AgNPs with average particle size of about 20 nm. The kinetic analysis revealed that the rate of bio-reduction of silver ions was very slow for initial 1h; however, later the reduction was fast as the development of characteristic color of AgNPs was completed within 5 hrs. This observation was concomitant with the appearance of the surface plasmon absorbance peak at ~ 430 nm. Further, these nanoparticles were used for the treatment of wound dressings by the exhaustion method. The so developed wound dressings showed good antibacterial activity against a gram positive bacterial strain Staphylococcus aureus
Vibration Based Tool Insert Health Monitoring Using Decision Tree and Fuzzy Logic
No full textThe productivity and quality in the turning process can be improved by utilizing the predicted performance of the cutting tools. This research incorporates condition monitoring of a non-carbide tool insert using vibration analysis along with machine learning and fuzzy logic approach. A non-carbide tool insert is considered for the process of cutting operation in a semi-automatic lathe, where the condition of tool is monitored using vibration characteristics. The vibration signals for conditions such as heathy, damaged, thermal and flank were acquired with the help of piezoelectric transducer and data acquisition system. The descriptive statistical features were extracted from the acquired vibration signal using the feature extraction techniques. The extracted statistical features were selected using a feature selection process through J48 decision tree algorithm. The selected features were classified using J48 decision tree and fuzzy to develop the fault diagnosis model for the improved predictive analysis. The decision tree model produced the classification accuracy as 94.78% with five selected features. The developed fuzzy model produced the classification accuracy as 94.02% with five membership functions. Hence, the decision tree has been proposed as a suitable fault diagnosis model for predicting the tool insert health condition under different fault conditions
A Novel Spacetime Collocation Meshless Method for Solving Two-Dimensional Backward Heat Conduction Problems
Get PDFIn this article, a meshless method using the spacetime collocation for solving the two-dimensional backward heat conduction problem (BHCP) is proposed. The spacetime collocation meshless method (SCMM) is to derive the general solutions as the basis functions for the two-dimensional transient heat equation using the separation of variables. Numerical solutions of the heat conduction problem are expressed as a series using the addition theorem. Because the basis functions are the general solutions of the governing equation, the boundary points may be collocated on the spacetime boundary of the domain. The proposed method is verified by conducting several heat conduction problems. We also carry out numerical applications to compare the SCMM with other meshless methods. The results show that the SCMM is accurate and efficient. Furthermore, it is found that the recovered boundary data on inaccessible boundary can be obtained with high accuracy even though the over specified data are provided only at a 1/6 portion of the spacetime boundary
Improved Particle Swarm Optimization for Selection of Shield Tunneling Parameter Values
Get PDFThis article proposes an exponential adjustment inertia weight immune particle swarm optimization (EAIW-IPSO) to enhance the accuracy and reliability regarding the selection of shield tunneling parameter values. According to the iteration changes and the range of inertia weight in particle swarm optimization algorithm (PSO), the inertia weight is adjusted by the form of exponential function. Meanwhile, the self-regulation mechanism of the immune system is combined with the PSO. 12 benchmark functions and the realistic cases of shield tunneling parameter value selection are utilized to demonstrate the feasibility and accuracy of the proposed EAIW-IPSO algorithm. Comparison with other improved PSO indicates that EAIW-IPSO has better performance to solve unimodal and multimodal optimization problems. When solving the selection of shield tunneling parameter values, EAIW-IPSO can provide more accurate and reliable references for the realistic engineering
Region-Aware Trace Signal Selection Using Machine Learning Technique for Silicon Validation and Debug
Get PDFIn today’s modern design technology, post-silicon validation is an expensive and composite task. The major challenge involved in this method is that it has limited observability and controllability of internal signals. There will be an issue during execution how to address the useful set of signals and store it in the on-chip trace buffer. The existing approaches are restricted to particular debug set-up where all the components have equivalent prominence at all the time. Practically, the verification engineers will emphasis only on useful functional regions or components. Due to some constraints like clock gating, some of the regions can be ignored during execution. Likewise, some of these regions can be verified deeply and have minimum errors compared to other control regions. The proposed system focusses on random signals that identify more errors which are prone to signal selection technique with low area overhead. To enhance the observability, a machine learning technique is developed. Based on the training samples of smaller designs, a model is developed to find out the contiguous neighbours of each flip-flop. This can eliminate the obstacles of unknown signals. This system demonstrates using Opencores and ISCAS’89 benchmark circuits that result in easy and fast error detection compared to the state-of-the-art of other methods. This is also verified using gate-level error models by cross-validation of each debug run
A Multiscale Method for Damage Analysis of Quasi-Brittle Heterogeneous Materials
Get PDFA novel multiscale algorithm based on the higher-order continuum at both micro- and macrostructural level is proposed for the consideration of the quasi-brittle damage response of heterogeneous materials. Herein, the microlevel damage is modelled by the degradation of the homogenized stress and tangent stiffness tensors, which are then upscaled to govern the localization at the macrolevel. The C1 continuity finite element employing a modified case of Mindlin’s form II strain energy density is derived for the softening analysis. To the authors’ knowledge, the finite element discretization based on the strain gradient theory is applied for the modeling of damage evolution at the microstructural level for heterogeneous materials for the first time. The advantage of the novel C1 finite element formulation in comparison with the standard finite element discretization in terms of the regularization efficiency as well as the objectivity has been shown. An isotropic damage law is used for the reduction of the constitutive and nonlocal material behaviour, which is necessary for the physically correct description of the localization formation in quasi-brittle materials. The capabilities of the derived finite element to capture the fully developed localization zones are tested on a random representative volume element (RVE) for several different loading cases. By employing the conventional second-order computational homogenization, the microstructural material constitutive response is averaged over the whole RVE area. In order to model the loss of structural integrity when sharp localization is formed across RVE, the specific conditions which detect a completely formed localization zone are developed. A new failure criterion at the microstructural level has been proposed. The derived finite element formulation, as well as the multiscale damage algorithm, are implemented into the finite element program ABAQUS. The capabilities of the presented multiscale scheme to capture the effects of the deformation localization are demonstrated by few benchmark numerical examples