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Operation Capability Analysis and Experiments of Underactuated Compliant Multi-Fingered Hands
Get PDFIn this paper, operation capabilities of underactuated compliant robot hands have been investigated based on the shape stability analysis of underactuated compliant fingers and operation modes analysis of human hands. It is shown that the operation modes of robot hands can be classified into two major classes, namely, enveloping grasp mode and pinch mode. For the two operation modes, two principles are respectively presented with regard to the mechanical design issues of the underactuated robot hands. According to the principles presented in this paper, a robot hand prototype with four underactuated compliant fingers has been fabricated. On the robot hand prototype, enveloping grasp capability of underactuated compliant robot hands has been verified by many experiments. For precision operations, a proposition is presented and it is shown that the prototype should be further improved
Solar Energy in Latin America and the Caribbean: The Current Situation and Perspectives in the Use of Solar Energy for Electricity Generation
Get PDFWithout a doubt, Latin America and the Caribbean will significantly contribute to the continuous global solar capacity expansion during the coming decades. The whole region could grow its current installed solar power capacity by a factor of 40 by 2050. It is expected that by 2050, solar power would represent the second-largest power source behind wind power, generating around 25% of the world’s power. The Int?rn?t??n?l Energy Ag?n?? (IEA) projected, in 2014, that under ?t? high r?n?w?bl?? scenario, by 2050, solar PV and ??n??ntr?t?d ??l?r power (CSP) would contribute about 16% and 11%, r?????t?v?l?, of the worldwide electricity ??n?um?t??n. ??l?r power is expected to be the largest ??ur?? of ?l??tr???t? generation at the world level in 2050. In total, global solar power capacity would increase around 14-folds, rising from 578,6 GW in 2019 to over 8.000 GW by 2050. Annual investments in solar power are likely to exceed US$7 billion
Enhancement of Tuberculosis Detection Using Ensemble Classifier with Quadtree Method: A Preliminary Study
Get PDFTuberculosis is an infectious disease caused by a bacillus called Mycobacterium tuberculosis. It can lead to death in untreated and inappropriately treated patients. An early diagnosis of the disease not only improves treatment success but also reduces death rates. Lung region is the most affected part of Tuberculosis and the process of medical image classification is still carried out manually using the knowledge of the physician or radiologist, which leads to inaccurate and slow process of TB identification. Therefore, this study proposed to enhance tuberculosis detection using a different combination of machine learning and image processing methods on the image dataset
IoT-Based System Monitoring of the Sleep Environment - A Study Aimed at the Elderly
Get PDFThe aging process in our population can cause changes in people’s sleeping patterns, more specifically in the elderly, by impairing their cognitive abilities, quality of life, and autonomy. Advances in Ubiquitous Computing and Internet of Things have contributed to the monitoring of such situations. In particular, the use of sensors to evaluate the environment and aspects related to the health and well-being of individuals, as well as providing event alerts. The main objective of this experiment is to propose a monitoring system based on both the responses of multiple sensors (brightness, microphone, accelerometer, and gyroscope) at runtime to classify the environment for elderly people’s sleep quality. The results show that using embedded devices, and capturing environmental aspects through sensors, can develop solutions that offer more safety and comfort to the individuals’ sleep quality environment
Fracture and Permeability Properties of Artificial Fly Ash and Slag aggregate Concretes at Different Water-to-Cement Ratios
Get PDFThis study presents an experimental investigation on the effect of artificial aggregate utilization fracture and permeability properties of concretes. For this, two types of artificial aggregates, namely, artificial fly ash aggregate (AFA) from cold bonding agglomeration process of fly ash and Portland cement and artificial slag aggregate (ASA) from cold bonding agglomeration process of ground granulated blast furnace slag and Portland cement, were replaced with natural aggregate to coarse aggregate. Moreover, to investigate the influence of water-to-cement ratio, three different water-tocement ratios of 0.35, 0.45, and 0.55 were considered in the concrete production. The concretes were tested for the mechanical property in terms of as compressive strength, modulus of elasticity, and splitting, net flexural strength, and fracture energy and also permeability property such as water sorptivity, water penetration, gas permeability, and resistance to chloride ion penetration. The test results were also analyzed by means of statistical technique, namely, GLM-ANOVA. It was found that the use of cold bonded fly ash and slag aggregates were very effective on the performance characteristics of concretes depending on w/c ratio
Synthesis, Characterization and Mechanical Behaviour of Al2O3, TiO2, and Cu Reinforced Al 7068 Nanocomposites
Get PDFThis present research work aims at fabrication of AA7068 metal matrix composite reinforced with a different weight percentage of Al2O3, TiO2 and Cu (0 wt.%, 2 wt.%, and 4 wt.%) nanopowders through mechanical alloying of 30 hrs which is produced using powder metallurgy route. The consolidation pressure of 500 MPa was applied for compaction of the composite and sintered at a temperature of 600°C for two hrs in the presence of argon gas flow. An XRD result reveals that there are no intermetallic compounds formed in the milled powder after 30 hr of mechanical alloying. The reinforcement particles were well embedded and uniformly distributed in matrix composites was confirmed by bright-field emission transmission electron microscopy (FETEM) image and selected area diffraction (SAD) ring pattern. From the DSC curve of AA 7068–2.0 wt. % Al2O3, TiO2 and Cu nanocomposite powders after 30 hrs of mechanical alloying., the endothermic peak at 536.85°C corresponds to the melting of aluminium which was followed by a steady-state exothermic reaction at 579.51°C was obtained. The green density and sintered density of prepared nanocomposites were calculated and compared. Brinell hardness test has been conducted and the maximum value of 192 BHN was obtained by adding a weight percentage of 2 wt. % of Al2O3, TiO2 and Cu particles
Fabrication and Characterization of DSSC/Si Tandem Solar Cell with PEDOT:PSS/ITO Buffer Layer
Get PDFIn this study, dye-sensitized solar cell (DSSC)/silicon tandem solar cells were fabricated by changing the buffer layer structure. When joining two cells, a buffer layer is important to efficiently transport electrons by suppressing buffer of electrons by a potential barrier. Therefore, we used PEDOT:PSS/ITO as buffer layer structures, and measured their solar cell characteristics. As a result, it was found that the structure in which both PEDOT:PSS layer and ITO layer are stacked as buffer layers is suitable for the buffer layer of DSSC/Si tandem cells. In addition, the characteristics improved each time DMSO was added to PEDOT:PSS, and as a result, the characteristics of tandem solar cells also tended to improve. The maximum conversion efficiency (Voc = 0.78 V, Jsc = 4.87 mA / cm2, FF = 0.62, Eff = 2.35 %) was obtained when the DMSO concentration was 1%. It was suggested that conversion efficiency can be improved by improving the buffer layer
Review of the PV Electricity Production Estimate under the Effect of Climatic Disturbances and Sunspots by Using Deep-Learning Tools
Get PDFThe mathematical models used in the estimation of GHI on the Earth\u27s surface are inconvenient because they always assume that the sky clarity index is constant. Hence, these models are often confronted with long-period empirical ground measurements that may exceeds 11 years. The impact of cloud cover on an electric power generation site is a very critical parameter for installing a solar power plant and evaluating its productivity. The state of knowledge about the sun influence, the greenhouse effect on climate change, and cloud occurrence can’t be described in a mathematical or numerical model.Therefore, in this paper, we propose the use of Deep-Learning techniques to predict any site’s productivity by analyzing its potential insolation. We also suggest the analysis of the ground and satellite- based measurements collected over 30 years. We propose the estimation of future climate change affecting cloud cover
Characteristics for Improvement of Compressive Strength of Geopolymers Made of Mixed Binders
Get PDFGeopolymers are composite hard materials made by mixing binders, such as fly ash and slags, and activators, such as NaOH and sodium silicate. The chemical mechanism for hardening composite materials, aluminosilicate binders, with alkaline activators is known as a geopolymer reaction. Geopolymers have recently been developed to be used as a replacement for Portland cement concrete. Industrial by-products such as fly ash, steel making slags, and garbage melting furnace slags can be made into geopolymers in a process that emits less carbon dioxide than in the cement making process. This reduction in CO2 emission is important because CO2 is one of the substances known to contribute to global warming. In the future, further uses of these fly ash and slags must be explored. The development of high compressive strength geopolymers using fly ash and slags will strongly contribute to the fields of construction, geotechnical engineering, and architecture.
So far, ground blast furnace slag has yielded the highest compressive strength geopolymer among various kind of binders such as fly ash, ground stainless steel-making slag, and garbage melting furnace slags. A potential use for the poor binders, yielding low compressive strength geopolymers, is to combine it with a richer binder to create stronger products. This paper examines the characteristics for improvement of compressive strength of geopolymers for the binders in various mixture ratios of poor binders and the ground blast furnace slag
Grading of Spot Welding Electrode Material Properties Using AHP
Get PDFAn objective of this research is to rank the essential property required for spot welding material selection. Total ten attributes namely Electrical conductivity, Thermal conductivity, Rockwell Hardness, Wear resistance, Density, Cost, Melting point, Percentage Elongation, Yield Strength and Ultimate Tensile Strength were considered for the purpose of selection of the electrode Material. In order to select appropriate spot welding electrode, authors have studied various Copper alloys having equally good properties. The selection of essential properties was done using Analytical Hierarchy Process (AHP). Experimental work have been carried out on Cu-Cr-Zr material using universal tensile and found that the strength and hardness increases with alloying element, however percentage elongation decreases by 50 % as compared to pure Cu. While performing AHP, the authors found that electrical conductivity, wear resistance, thermal conductivity and Rockwell hardness proved to be the most crucial parameters. Wear of electrode material also affects on current density and performance characteristics of spot welding process and makes it more expensive. The ranking of the property thus provide an input to apply various Multi-Attribution Decision Making (MADM) techniques for selection of the appropriate material for spot welding application. This work is recommended to spot welding electrode manufacturers as well as end users in order to prioritize the properties for selection of spot welding electrode with longer life and good weld quality