scholarly journals Design of Mechanism and Preliminary Field Validation of Low-Cost, Passive Prosthetic Knee for Users With Transfemoral Amputation in India

2015 ◽  
Author(s):  
V. N. Murthy Arelekatti ◽  
Amos G. Winter
Keyword(s):  
Early Stage ◽  
Low Cost ◽  
Metabolic Cost ◽  
Functional Requirements ◽  
Transfemoral Amputation ◽  
Prosthetic Knee ◽  
Gait Kinematics ◽  
Flexion Extension ◽  
Economic Constraints ◽  
Kinetics Of

An estimated 230,000 above-knee amputees in India are currently in need of prosthetic care, a majority of them facing severe socio-economic constraints. However, only few passive prosthetic knee devices in the market have been designed for facilitation of normative gait kinematics and for meeting the specific daily life needs of above-knee amputees in the developing world. Based on the results of our past studies, this paper establishes a framework for the design of a low-cost prosthetic knee device, which aims to facilitate able-bodied kinematics at a low metabolic cost. Based on an exhaustive set of functional requirements, we present a prototype mechanism design for the low-cost prosthetic knee. The mechanism is implemented using an early stance lock for stability and two friction dampers for achieving able-bodied kinematics and kinetics of walking. For early-stage validation of the prosthesis design, we carry out a preliminary field trial on four above-knee amputees in India and collect qualitative user feedback. Future iterations of the mechanism prototype will incorporate an additional spring component for enabling early stance flexion-extension.

scholarly journals Design and Preliminary Field Validation of a Fully Passive Prosthetic Knee Mechanism for Users With Transfemoral Amputation in India

2018 ◽  
Vol 10 (3) ◽  
Author(s):  
V. N. Murthy Arelekatti ◽  
Amos G. Winter
Keyword(s):  
Low Cost ◽  
Metabolic Cost ◽  
Metabolic Energy ◽  
Biomechanical Analysis ◽  
Functional Requirements ◽  
Timely Initiation ◽  
Prosthetic Devices ◽  
Prosthetic Knee ◽  
Flexion Extension ◽  
Economic Constraints

An estimated 230,000 above-knee amputees in India are currently in need of prosthetic devices, a majority of them facing severe socio-economic constraints. However, only a few passive prosthetic knee devices in the market have been designed for facilitation of normative gait kinematics and for meeting the specific daily life needs of above-knee amputees in the developing world. Based on the results of our past studies, this paper establishes a framework for designing a potentially low-cost, fully passive prosthetic knee device, which aims to facilitate able-bodied kinematics at a low metabolic cost. Based on a comprehensive set of functional requirements and biomechanical analysis from our past work, we present an early prototype mechanism for the prosthetic knee joint that is primarily focused on enabling able-bodied kinematics. The mechanism is implemented using two functional modules: an automatic early stance lock for stability and a differential friction damping system for late stance and swing control. For preliminary, qualitative validation of the knee mechanism, we carried out a field trial on four above-knee amputees in India, which showed satisfactory performance of the early stance lock. The prototype enabled smooth stance-to-swing transition by timely initiation of late stance flexion. Possible methods of incorporating an additional spring module for further refinement of the design are also discussed, which can enable flexion-extension during the early-stance phase of the gait cycle and potentially reduce the metabolic energy expenditure of the user further.

scholarly journals Modular Design of a Passive, Low-Cost Prosthetic Knee Mechanism to Enable Able-Bodied Kinematics for Users With Transfemoral Amputation

2017 ◽  
Author(s):  
Molly A. Berringer ◽  
Paige J. Boehmcke ◽  
Jason Z. Fischman ◽  
Athena Y. Huang ◽  
Youngjun Joh ◽  
...  
Keyword(s):  
High Performance ◽  
Stance Phase ◽  
Modular Design ◽  
Low Cost ◽  
Metabolic Cost ◽  
User Testing ◽  
Transfemoral Amputation ◽  
Prosthetic Knee ◽  
Adjustable Mechanism ◽  
Transfemoral Amputees

There is a significant need for low-cost, high-performance prosthetic knee technology for transfemoral amputees in India. Replicating able-bodied gait in amputees is biomechanically necessary to reduce the metabolic cost, and it is equally important to mitigate the socio-economic discrimination faced by amputees in developing countries due to their conspicuous gait deviations. This paper improves upon a previous study of a fully passive knee mechanism, addressing the issues identified in its user testing in India. This paper presents the design, analysis and bench-level testing of the three major functional modules of the new prosthetic knee architecture: (i) a four-bar latch mechanism for achieving stability during stance phase of walking, (ii) an early stance flexion module designed by implementing a fully adjustable mechanism, and (iii) a hydraulic rotary damping system for achieving smooth and reliable swing-phase control.

scholarly journals Designing a Low-Cost Ceramic Water Filter Press

2013 ◽  
Vol 8 (1) ◽  
pp. 62-77 ◽  
Author(s):  
Michael Henry ◽  
Siri Maley ◽  
Khanjan Mehta
Keyword(s):  
Diarrheal Disease ◽  
Early Stage ◽  
Low Cost ◽  
Field Testing ◽  
Filter Press ◽  
Concept Design ◽  
Functional Requirements ◽  
Middle Income ◽  
Major Barrier ◽  
Water Filter

Diarrheal disease due to unsanitary water is a leading cause of death in low- and middle- income countries. One potential solution to this problem is widespread access to point-of-use ceramic water filters made from universally-available materials. This increased access can be achieved by empowering local artisans to initiate self-sustaining and scalable entrepreneurial ventures in their communities. However, a major barrier to the start-up of these businesses is the prohibitively expensive press used to form the filters. This article reviews filter press technologies and identifies specific functional requirements for a more suitable and affordable filter press. Early-stage field-testing results of a proof-of-concept design that can be manufactured by two people in two days at one-tenth of the cost of popular filter presses is presented.

Study of the Cu(II) removal from aqueous solutions by adsorption on titania

2013 ◽  
Vol 12 (3) ◽  
pp. 239-247
Keyword(s):  
Heavy Metals ◽  
Ionic Strength ◽  
Toxic Metals ◽  
Low Cost ◽  
Lateral Interaction ◽  
Tio2 Surface ◽  
High Toxicity ◽  
Removal Of Heavy Metals ◽  
Solution Parameters ◽  
Kinetics Of

The removal of heavy metals from wastewaters is a matter of paramount importance due to the fact that their high toxicity causes major environmental pollution problems. One of the most efficient, applicable and low cost methods for the removal of toxic metals from aqueous solutions is that of their adsorption on an inorganic adsorbent. In order to achieve high efficiency, it is important to understand the influence of the solution parameters on the extent of the adsorption, as well as the kinetics of the adsorption. In the present work, the adsorption of Cu(II) species onto TiO2 surface was studied. It was found that the adsorption is a rapid process and it is not affected by the value of ionic strength. In addition, it was found that by increasing the pH, the adsorbed amount of Cu2+ ions and the value of the adsorption constant increase, whereas the value of the lateral interaction energy decreases.

scholarly journals Automation of absolute protein-ligand binding free energy calculations for docking refinement and compound evaluation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Germano Heinzelmann ◽  
Michael K. Gilson
Keyword(s):  
Free Energy ◽  
Early Stage ◽  
Binding Free Energy ◽  
Low Cost ◽  
Free Energy Calculations ◽  
Free Energies ◽  
Energy Calculations ◽  
Drug Candidates ◽  
Binding Free Energy Calculations ◽  
Binding Free Energies

AbstractAbsolute binding free energy calculations with explicit solvent molecular simulations can provide estimates of protein-ligand affinities, and thus reduce the time and costs needed to find new drug candidates. However, these calculations can be complex to implement and perform. Here, we introduce the software BAT.py, a Python tool that invokes the AMBER simulation package to automate the calculation of binding free energies for a protein with a series of ligands. The software supports the attach-pull-release (APR) and double decoupling (DD) binding free energy methods, as well as the simultaneous decoupling-recoupling (SDR) method, a variant of double decoupling that avoids numerical artifacts associated with charged ligands. We report encouraging initial test applications of this software both to re-rank docked poses and to estimate overall binding free energies. We also show that it is practical to carry out these calculations cheaply by using graphical processing units in common machines that can be built for this purpose. The combination of automation and low cost positions this procedure to be applied in a relatively high-throughput mode and thus stands to enable new applications in early-stage drug discovery.

Statistical Modeling, Optimization and Kinetics of Mn2+ Adsorption in Aqueous Solution Using a Biosorbent

2019 ◽  
Vol 233 (8) ◽  
pp. 1201-1214 ◽  
Author(s):  
Elaheh Tajari ◽  
Narges Samadani Langeroodi ◽  
Mahnaz Khalafi
Keyword(s):  
Wheat Bran ◽  
Low Cost ◽  
Weight Ratio ◽  
P Value ◽  
Core Shell ◽  
Optimal Conditions ◽  
Solution Ph ◽  
Shell Weight ◽  
Removal Ratio ◽  
Kinetics Of

Abstract This paper describes the adsorption of Mn2+ ions from water with a mixture of wheat bran and Japanese medlar core shell (weight ratio of 30–70 wheat bran to Japanese medlar core shell) as low-cost adsorbent. Scanning Electron Microscope was used to characterize the adsorbent. The response surface methodology (RSM) that is usually approximated by a second-order regression model was employed to evaluate the effects of solution pH, initial Mn2+ concentration, adsorbent weight and contact time on the removal ratio of the Mn2+ ions. In this regard, the significant variables initial Mn2+ ions concentration, pH, adsorbent weight and square pH were found based on the small P-value for the model coefficients. The predicted optimal conditions were also performed. In the process optimization, maximal value of the removal ratio of Mn2+ was achieved as 96.91%. Additionally, this paper discusses the kinetic of adsorption in optimal conditions.

scholarly journals Improvement of Hydrogen Desorption Characteristics of MgH2 With Core-shell Ni@C Composites

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3113 ◽  
Author(s):  
Cuihua An ◽  
Qibo Deng
Keyword(s):  
Low Cost ◽  
Hydrogen Desorption ◽  
Core Shell ◽  
Desorption Kinetics ◽  
Hydrogen Storage Materials ◽  
High Hydrogen ◽  
Dehydrogenation Kinetics ◽  
Materials Research ◽  
High Theoretical Capacity ◽  
Kinetics Of

Magnesium hydride (MgH2) has become popular to study in hydrogen storage materials research due to its high theoretical capacity and low cost. However, the high hydrogen desorption temperature and enthalpy as well as the depressed kinetics, have severely blocked its actual utilizations. Hence, our work introduced Ni@C materials with a core-shell structure to synthesize MgH2-x wt.% Ni@C composites for improving the hydrogen desorption characteristics. The influences of the Ni@C addition on the hydrogen desorption performances and micro-structure of MgH2 have been well investigated. The addition of Ni@C can effectively improve the dehydrogenation kinetics. It is interesting found that: i) the hydrogen desorption kinetics of MgH2 were enhanced with the increased Ni@C additive amount; and ii) the dehydrogenation amount decreased with a rather larger Ni@C additive amount. The additive amount of 4 wt.% Ni@C has been chosen in this study for a balance of kinetics and amount. The MgH2-4 wt.% Ni@C composites release 5.9 wt.% of hydrogen in 5 min and 6.6 wt.% of hydrogen in 20 min. It reflects that the enhanced hydrogen desorption is much faster than the pure MgH2 materials (0.3 wt.% hydrogen in 20 min). More significantly, the activation energy (EA) of the MgH2-4 wt.% Ni@C composites is 112 kJ mol−1, implying excellent dehydrogenation kinetics.

Cooling of Fruit with Arbitrary Shape: Simulation Using Galerkin-Based Integral Method

2017 ◽  
Vol 10 ◽  
pp. 1-15
Author(s):  
P. Morais Pessôa ◽  
A.G. Barbosa de Lima ◽  
R. Swarnakar ◽  
J.P. Gomes ◽  
W.M.P. Barbosa de Lima
Keyword(s):  
Integral Method ◽  
Arbitrary Shape ◽  
Heat Conduction Equation ◽  
Low Cost ◽  
Experimental Studies ◽  
Volume Ratio ◽  
Transient Heat Conduction ◽  
Cooling Time ◽  
Time Required ◽  
Kinetics Of

Cooling has been used for the preservation of fresh produce such as fruit and vegetables due to its low cost and high effectiveness in maintaining the product quality. Recently, several researchers have conducted theoretical and experimental studies for obtaining the kinetics of cooling and cooling time for fruits with different geometries. Present work, therefore, aims to simulate the cooling of fruits with particular reference to banana, orange, strawberry and Tahiti lemon. The transient heat conduction equation and its analytical solution using Galerkin based integral method are presented. It has been found that the strawberry has lower dimensionless cooling time compared with time required to cool other fruits, which is due to its higher surface area/volume ratio value. In orange and lemon the temperature distribution was found to be homogeneous in the angular direction, while in banana and strawberry it was two-dimensional due to shape of the fruits.

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