Experimental Testing of Passive Linear TMD for Postural Tremor Attenuation

Research interest to provide a mechanical solution for involuntary tremors is increasing due to the severe side effects caused by the medications used to lessen its symptoms. This paper deals with the design of a cantilever-type tuned mass damper (TMD) used to prove the effectiveness of passive controllers in reducing the involuntary tremor’s vibrational signals transmitted by the muscles to the hand segment. TMD is tested on an experimental arm, reflecting the flexion-extension motion of the wrist, excited by a mechanical shaker with the measured tremor signal of a patient with essential tremor. The designed TMD provides a new operational frequency for each position of the screw fixed to its beam. Modal damping ratios are also calculated using different methods for each position. The effectiveness of the TMD is quantified by measurements using a vibrometer and inertial measurement unit. Three TMDs, representing 15.7% total mass ratio, cause a reduction of 29% for the acceleration, 69% for the velocity, 79% for the displacement, 67% for the angular velocity, and 82% for the angular displacement signals. These encouraging results will allow the improvement of the design of the passive controller in the form of a wearable bracelet suitable for daily life.

Investigation of 2D Rainbow Metamaterials for Broadband Vibration Attenuation

Phononic crystals (PnCs) and metamaterials are widely investigated for vibration suppression owing to the bandgaps, within which, wave propagation is prohibited or the attenuation level is above requirements. The application of PnCs and metamaterials is, however, limited by the widths of bandgaps. The recently developed rainbow structures consisting of spatially varied profiles have been shown to generate wider bandgaps than periodic structures. Inspired by this design strategy, rainbow metamaterials composed of nonperiodic mass blocks in two-dimensional (2D) space were proposed in the present study. The blocks were connected by curved beams and tessellated with internal voids to adjust their masses. In order to demonstrate the effects of the rainbow design, two 2D metamaterials, with periodic and nonperiodic units, respectively, were investigated and manufactured using additive manufacturing technologies. Receptance functions, i.e., displacement frequency response functions, of the manufactured metamaterials were calculated with finite element models and measured with a testing system containing a mechanical shaker, an impedance head, and a laser Doppler vibrometer. The obtained numerical and experimental results showed that the metamaterial with rainbow blocks has extended bandgaps compared with the periodic metamaterial.

Evaluation of different solvent extracts of sweet flag rhizome, Acorus calamus (L.) on pulse beetle, Callosobruchus maculatus (F.)

Investigation was conducted to test the insecticidal activity of sweet flag rhizome (Acorus calamus L.) extracts on Callosobruchus maculatus (F.) on cow pea in storage during 2016-2017 at the Department of Agricultural Entomology, Agricultural College and Research Institute, Coimbatore. Sweet flag (SF) extracts obtained by different extraction methods (soxhlet and mechanical shaker extraction) using various solvents viz., hexane, ethyl acetate and ethanol exhibited varied levels of insecticidal action on Callosobruchus maculatus (F.). Pulse beetle on cow pea seeds, there was a positive correlation between the concentration of the sweet flag extracts and the insecticidal action. The LC50 value of hexane, ethyl acetate and ethanol extract of SF obtained in soxhlet extraction for C. maculatus was 0.042, 0.230 and 0.069 per cent at 48 hours, respectively. The LC50 value of hexane, ethyl acetate and ethanol extract of SF obtained in mechanical shaker extraction for C. maculatus was 0.009, 0.275 and 0.069 per cent at 48 hours, respectively. Hexane extract of SF obtained from both extraction methods (soxhlet and mechanical shaker) showed cent per cent mortality at 0.09 and 0.1 per cent on 5th day after treatment (DAT). For ethyl acetate and ethanol extracts of SF obtained from both extraction methods (soxhlet and mechanical shaker), caused more than 80 per cent mortality was observed on 6th DAT at 0.09 and 0.1 per cent on pulse beetle respectively. On 90 DAT, hexane extract of SF obtained from both extraction methods and of ethyl acetate extract of SF obtained from mechanical shaker extraction, there was no progeny development of C. maculatus at 0.05, 0.07, 0.09 and 0.1per cent concentrations. Cent per cent mortality and there is no progeny development C. maculatus in 0.09 and 0.1 per cent of hexane extract of SF (both extraction methods) and ethyl acetate extract of SF (mechanical shaker extraction) treated cowpea seeds upto 90 days when compared to untreated control.

Influence of Different Sieving Methods on Estimation of Sand Size Parameters

Sieving is one of the most used operational methods to determine sand size parameters which are essential to analyze coastal dynamics. However, the influence of hand versus mechanical shaking methods has not yet been studied. Herein, samples were taken from inside the hopper of a trailing suction dredger and sieved by hand with sieves of 10 and 20 cm diameters on board the dredger. Afterwards, these same samples were sieved with a mechanical shaker in the laboratory on land. The results showed differences for the main size parameters D50, standard deviation, skewness, and kurtosis. Amongst the main results, it should be noted that the highest values for D50 and kurtosis were given by the small sieves method. On the other hand, the lowest values were given by the mechanical shaker method in the laboratory. Furthermore, standard deviation and skewness did not seem to be affected by the sieving method which means that all the grainsize distribution was shifted but the shape remained unchanged. The few samples that do not follow these patterns have a higher percentage of shells. Finally and definitely, the small sieves should be rejected as a sieving method aboard.

Experimental research on influence of functional parameters of combined installations designed at separating the impurities out of cereal seeds

The paper presents the experimental installation, the methodology and measuring apparatus used for experimental research of qualitative indexes of impurities separation out of grain seeds for combined separating systems (according to specific weight and aerodynamic properties of seeds). The experimental installation used was composed of a gravimetric separator with mechanical shaker with unbalanced masses (mounted on the platform working surface) and an aspiration installation with fan. The experimental research has aimed at quantitative and qualitative influence on separation quality index of the following operating parameters: material flow rate of shaking separator, the air flow of aspiration installation, tilting work surface, work surface oscillation amplitude. Based on data obtained by measurements and qualitative indicators the separating process indexes have been determined, namely: degree of impurities separation, degree of good seeds loss, as well as, the separation quality index for different types of combinations of separation installation parameters.

Treatment of Acid Orange 74 Wastewater and Sugar Wastewater by Low Cost Adsorbents

This study shows the treatment of combined binary mixture of Acid Orange 74 and sugar wastewater with peanut hull and orange peel as low-cost adsorbents. The performance of a combined adsorption-microfiltration process for the color removal is measured and compared using transmittance and absorbance indices at mechanical shaker mix level. This selected treatment procedure is among one of the most economical treatment alternatives to all technologies present now. The parameters studied during this research are analyzed using Langmuir and Freundlich isotherm models on low cost adsorbents. Conclusive results after the treatment are indicated in this paper at their optimum dosages and sizes. This treatment method is applicable in the actual conditions at territory treatment stage.

Accuracy of Samsung Gear S Smartwatch for Activity Recognition: Validation Study (Preprint)

BACKGROUND Wearable accelerometers have greatly improved measurement of physical activity, and the increasing popularity of smartwatches with inherent acceleration data collection suggest their potential use in the physical activity research domain; however, their use needs to be validated. OBJECTIVE This study aimed to assess the validity of accelerometer data collected from a Samsung Gear S smartwatch (SGS) compared with an ActiGraph GT3X+ (GT3X+) activity monitor. The study aims were to (1) assess SGS validity using a mechanical shaker; (2) assess SGS validity using a treadmill running test; and (3) compare individual activity recognition, location of major body movement detection, activity intensity detection, locomotion recognition, and metabolic equivalent scores (METs) estimation between the SGS and GT3X+. METHODS To validate and compare the SGS accelerometer data with GT3X+ data, we collected data simultaneously from both devices during highly controlled, mechanically simulated, and less-controlled natural wear conditions. First, SGS and GT3X+ data were simultaneously collected from a mechanical shaker and an individual ambulating on a treadmill. Pearson correlation was calculated for mechanical shaker and treadmill experiments. Finally, SGS and GT3X+ data were simultaneously collected during 15 common daily activities performed by 40 participants (n=12 males, mean age 55.15 [SD 17.8] years). A total of 15 frequency- and time-domain features were extracted from SGS and GT3X+ data. We used these features for training machine learning models on 6 tasks: (1) individual activity recognition, (2) activity intensity detection, (3) locomotion recognition, (4) sedentary activity detection, (5) major body movement location detection, and (6) METs estimation. The classification models included random forest, support vector machines, neural networks, and decision trees. The results were compared between devices. We evaluated the effect of different feature extraction window lengths on model accuracy as defined by the percentage of correct classifications. In addition to these classification tasks, we also used the extracted features for METs estimation. RESULTS The results were compared between devices. Accelerometer data from SGS were highly correlated with the accelerometer data from GT3X+ for all 3 axes, with a correlation ≥.89 for both the shaker test and treadmill test and ≥.70 for all daily activities, except for computer work. Our results for the classification of activity intensity levels, locomotion, sedentary, major body movement location, and individual activity recognition showed overall accuracies of 0.87, 1.00, 0.98, 0.85, and 0.64, respectively. The results were not significantly different between the SGS and GT3X+. Random forest model was the best model for METs estimation (root mean squared error of .71 and r-squared value of .50). CONCLUSIONS Our results suggest that a commercial brand smartwatch can be used in lieu of validated research grade activity monitors for individual activity recognition, major body movement location detection, activity intensity detection, and locomotion detection tasks.

Construction and Evaluation of a Uniaxial Mechanical Actuated Vibration Shaker

In the present paper a low cost mechanical vibration shaker of rotating unbalanced type with uniaxial shaking table was designed and constructed in an attempt to provide opportunities for experimental testing and application of vibration in experimental modal analysis, stress relief of weldments, effect of vibration on heat transfer and seismic testing of civil engineering structures. Also, it provides unexpressive solution to enhance the knowledge and technical skills of students in mechanical vibration laboratory. The shaker consists of a five main parts shaker frame, shaker table, flexible support, drive motor, and eccentricity mechanism. The experimental results show that the amplitude of the shaker is increased with increasing the frequency ratio and the maximum value was attained near the resonance condition. Also, the magnitude of amplitude is increased with increasing the eccentric mass and eccentricity values. A reasonable agreement with theoretical results shows that the shaker can be used with reliable results in vibration testing purposes. Also, in this paper, the frequency ranges of the shaker were determined for constant displacement and for constant acceleration tests to satisfy all the frequency limitation requirements of the mechanical shaker.

Mechanical vibrations in the transport of hatching eggs and the losses caused in the hatch and quality of broiler chicks

Many factors present in eggs’ transportation from incubator to growing confinements can damage their integrity and, consequently, the results of the incubation. This study aimed to evaluate whether the intensity and duration of exposures of hatching eggs to mechanical vibrations were capable of affecting the hatch and the quality of broiler chicks. Four treatments, determined by two intensities of vibrations and two durations of exposures were evaluated and compared with a control group in a randomised design in blocks with four repetitions. The vibrations were applied by a mechanical shaker before incubation. Then the eggs were incubated and as the following responses were evaluated: hatchability, the type of embryonic mortality, the quality of the birds and the total of losses. The analyses were carried out by a binomial regression model, with application of the Wald test at 5% significance level. The results showed that the exposure of eggs to mechanical vibrations harmfully affects the hatchability and reduces the ratio (percentage) of high quality chicks. Highest vibration level together with longer duration of exposure resulted in worst hatchability and losses. It is argued that the mechanical vibrations are potentially damaging and should be regarded as an important factor in the management of hatching eggs.

ROLE OF SUSPENDED PARTICULATE MATTER IN ANGIOGENESIS EMPLOYING CROWN GALL TUMOR ASSAY

<p><strong>Objective: </strong>Aim of the study was to screen the suspended particulate matter for their role in enhancing angiogenesis employing crown gall tumor assay.</p><p><strong>Methods: </strong>Particulate matter (PM₁₀) samples were collected, on glass fiber filter paper at the rate of 1.12–1.14 m^3/min for 8 hr using high volume sampler, from six different sites of Amritsar city. Aqueous extracts of suspended particulate matter were prepared using a mechanical shaker for 24 hour and the filtrate was centrifuged and lyophilized.</p><p><strong>Results: </strong>Maximum (34.67±1.764) tumors were induced by samples collected from Crystal chowk whereas tumor inducing ratio (TIR) was found to be comparably high for two sites <em>viz.,</em> Crystal chowk and Bhandari bridge.</p><p><strong>Conclusion: </strong>High tumor inducing ratio at the above-mentioned sites was correlated to high traffic emission from automobile exhaust. Crown gall tumor assay has been proved to be rapid, economical and reliable screening assay for angiogenesis agent.</p>