Mohammad S. Hammoud

Tremor Reduction at the Palm of a Parkinson’s Patient Using Dynamic Vibration Absorber

Parkinson’s patients suffer from severe tremor due to an abnormality in their central oscillator. Medications used to decrease involuntary antagonistic muscles contraction can threaten their life. However, mechanical vibration absorbers can be used as an alternative treatment. The objective of this study is to provide a dynamic modeling of the human hand that describes the biodynamic response of Parkinson’s patients and to design an effective tuned vibration absorber able to suppress their pathological tremor. The hand is modeled as a three degrees-of-freedom (DOF) system describing the flexion motion at the proximal joints on the horizontal plane. Resting tremor is modeled as dual harmonic excitation due to shoulder and elbow muscle activation operating at resonance frequencies. The performance of the single dynamic vibration absorber (DVA) is studied when attached to the forearm and compared with the dual DVA tuned at both excitation frequencies. Equations of motion are derived and solved using the complex transfer function of the non-Lagrangian system. The absorber’s systems are designed as a stainless steel alloy cantilevered beam with an attached copper mass. The dual DVA was the most efficient absorber which reduces 98.3%–99.5%, 97.0%–97.3% and 97.4%–97.5% of the Parkinson’s tremor amplitude at the shoulder, elbow and wrist joint.

Analytical Modeling: Three Stages Homogenization Method

A small to moderate sized modern computer system employs advanced features such as fault-tolerance ( see Fault-tolerant systems), resource sharing and contention, concurrency an d synchronization, timeliness ( see Real-time systems), and degradable performance. When such a computer system i being designed and implemented, it becomes essential to answer “what-if” questions and carry out trade-o ff studies to choose between a set of contending design alternatives. The broad classes of measures that need to be valuated are:

Structural control and biomechanical tremor suppression: Comparison between different types of passive absorber

Active and semi-active control devices can be used as advanced and accurate controllers to reduce the undesired vibration of a structure. However, some of these controllers may have a complex design, especially for systems excited with multi-degree-of-freedom frequencies, which demand the use of high anti-fatigue material properties, and others that may require a large power source. So, improvements in the design of passive controllers are of high interest for researchers. These controllers have a very simple design and aim to counteract vibration with no power requirements. In this paper, six different passive controllers were designed to analyze and compare their performance. The performance is considered in terms of the percentage of reduction in the primary system’s displacement amplitude and the bandwidth of each designed passive controller. The system of interest is taken as the three-degree-of-freedom dynamic hand system reflecting the behavior of Parkinsonian patients. Four joint muscles operating at two resonance harmonic excitation frequencies are considered to produce movements. Each controller was attached to the forearm of the hand set in the horizontal plane to analyze their capability in reducing the rest tremor (3–7 Hz) at the proximal joint. The dual series elastic–viscous absorber is shown to be a very effective controller. It is formed from a series connection between an elastic absorber (mass–spring) and a viscous absorber (mass–dashpot). It causes about 80% reduction in tremor amplitude with 4 Hz wide frequency band at the shoulder, elbow and wrist joints. This range of operational frequency is close to that of healthy cases, 4.5 Hz.

Power from photovoltaic installed in the middle of the Lebanese high-ways: PV system in the middle of the high-ways

It is well-known that the bottleneck of Photovoltaic (PV) systems is the use of storage batteries and the area needed to install the system. The main idea in this work is to design a large PV system with almost zero cost of land needed for the installation, and without the need of batteries. The proposed PV system makes use of special areas of the Lebanese lands; the middle of high-ways which are usually left unoccupied without being exploited by any other business. This way, the traditional high cost of PV systems residing in the land and storage is eliminated. The fact that we do not need batteries in the proposed PV system results from the ability to connect the output power directly to the public utility grid. The design consists of 20,476 PV panels that cover the middle of the high-way extending from Tyre to Saida, with a distance of 27,300 meters and 2 meters wide. The resulting PV system has a capacity of 6.2 MW, and the total initial cost is ~8.845 M

A reduced simulation applied to the viscoelastic fatigue of polymers

, however, after 25 years (which is the proposed lifetime of the PV system) the project would generate a total of ~54.7 M

History and Origin of Natural Plant Fibers: Historical Background

. Moreover, the PV system would provide net reduction of CO2 and GHG emissions of ~7,388 tCO2/year.