Ergonomics evaluation of equipment adjustability for Mexican-American population

2003 ◽  
Vol 3 (1) ◽  
pp. 65-80
Author(s):  
Rolando Quintana ◽  
Jose A. Alonso
Keyword(s):  
Mexican American ◽  
Design Tool ◽  
The Body ◽  
Upper Body ◽  
Body Segments ◽  
Northern Mexico ◽  
The Us ◽  
The Mean ◽  
Occupational Disorders ◽  
Mexican American Population

The effects of lack of equipment adjustability on nominal ranges of motion of upper body limbs for industrial sewing operations were studied, with a particular focus on Mexican-American males. Key upper body-segments of an industrial sewing operation were marked and analyzed using cinematography for a random pool of male workers descending from northern Mexico. Experimental results revealed that the worker's posture was affected by the adjustability of the sewing equipment, which was designed for the 5th to the 95th percentile of the US population. The awkward postures in turn affected the mean angular range of motion for the body-segments studied. As a result, there was a significant percentage of the available pool of worker's that may face occupational disorders, in spite of the fact that the equipment is adjustable, albeit from the 5th to the 95th percentile of the US population. These findings are particularly important to companies whose workforce is predominantly from populations that do not fit the US population profile. An adjustability index tool was developed as an equipment purchase/design tool that quantifies the percentage of the available pool of workers at risk of occupational disorders due to improper postures resulting from lack of adjustability. Finally, a cost framework is presented for choosing equipment that minimizes internal and external costs associated with equipment adjustability.

Biodynamic Characteristics of Upper Limb Reaching Movements of the Seated Human Under Whole-Body Vibration

2013 ◽  
Vol 29 (1) ◽  
pp. 12-22 ◽  
Author(s):  
Heon-Jeong Kim ◽  
Bernard J. Martin
Keyword(s):  
Right Hemisphere ◽  
Whole Body Vibration ◽  
The Body ◽  
Upper Body ◽  
Whole Body ◽  
Vibration Transmission ◽  
Body Vibration ◽  
Body Segments ◽  
Human Movements ◽  
Reach Movements

Simulation of human movements is an essential component for proactive ergonomic analysis and biomechanical model development (Chaffin, 2001). Most studies on reach kinematics have described human movements in a static environment, however the models derived from these studies cannot be applied to the analysis of human reach movements in vibratory environments such as in-vehicle operations. This study analyzes three-dimensional joint kinematics of the upper extremity in reach movements performed in static and specific vibratory conditions and investigates vibration transmission to shoulder, elbow, and hand along the body path during pointing tasks. Thirteen seated subjects performed reach movements to five target directions distributed in their right hemisphere. The results show similarities in the characteristics of movement patterns and reach trajectories of upper body segments for static and dynamic environments. In addition, vibration transmission through upper body segments is affected by vibration frequency, direction, and location of the target to be reached. Similarities in the pattern of movement trajectories revealed by filtering vibration-induced oscillations indicate that coordination strategy may not be drastically different in static and vibratory environments. This finding may facilitate the development of active biodynamic models to predict human performance and behavior under whole body vibration exposure.

Analysis and modeling of human seat interaction with a focus on the upper body and backrest using biomechanics and contact mechanics

Work ◽  
2021 ◽  
Vol 68 (s1) ◽  
pp. S161-S182
Author(s):  
Yuezhi (Sean) Liu ◽  
Xianzhi Zhong ◽  
Wintta Ghebreiyesus ◽  
Jiancheng Ji ◽  
Fengfeng (Jeff) Xi
Keyword(s):  
Human Body ◽  
The Body ◽  
Contact Forces ◽  
Human Anatomy ◽  
Upper Body ◽  
Stress Theory ◽  
Body Segments ◽  
Seat Comfort ◽  
Muscular Structure ◽  
Point Forces

BACKGROUND: This paper outlines a method to study the interaction between the human body and the aircraft seat concerning the seat comfort. METHOD: Firstly, the human body is modeled based on biomechanics and divided into a number of body segments connected by joints according to human anatomy. The angles between the body segments are obtained by curve fitting of the existing biomechanical research data. The contact forces between the human body and the seat are modeled using pairs of bi-lateral point forces. These forces are calculated and located through the analysis of the center of gravity of each body segment and average muscular structure of the human body. The geometry of the human and the seat is obtained from a 3D scan model or a CAD model. Secondly, the pressure distribution between the human body and the seat is modeled and calculated using the contact stress theory. The results of the two parts are combined to analyze the comfortability in relation to different postures, backrest recline angles and changing in shape and material. RESULTS: Simulations were performed and they are compared with experimental measurement and various FEM studies for validation. It is found that accuracy of this method is comparable with most FEM calculation. CONCLUSION: This method provides a new direction in cushion conform research. It is faster and convenient to use comparing to the FEM, and the result is reliable.

scholarly journals Comparison of Kinematic Characteristics of Upper Body according to the Shooting of Elite Disabled Archery Athletes

2020 ◽  
Author(s):  
Taewhan Kim ◽  
JaeWon Lee ◽  
SeoungKi Kang ◽  
KyuYeon Chae ◽  
Sang-Hyup Choi ◽  
...  
Keyword(s):  
The Body ◽  
Lower Limbs ◽  
Upper Body ◽  
Phase 2 ◽  
Kinematic Characteristics ◽  
Significant Difference ◽  
Athletes With Disabilities ◽  
Body Center ◽  
The Mean ◽  
Time Required

The purpose of this study is to compare and analyze the kinematic characteristics of the upper limb segments during the archery shooting of Paralympic Wheelchair Class archers (ARW2 - second wheelchair class – paraplegia or comparable disability) and Paralympic Standing Class archers (ARST - standing archery class – loss of 25 points in the upper limbs or lower limbs), where archers are classified according to their disability grade among elite disabled archers. The participants of this study were selected as seven elite athletes with disabilities, 4 ARW2, and 3 ARST. The analysis variables were 1) the time required for each phase, 2) the angle of inclination of the body center, 3) the change of trajectory of body center, and 4) the change of movement locus of bow center by phase when performing six shots in total. The ARW2 group showed a longer time than the ARST group, and the angle of the body did not show a significant difference between the two groups. Although there was no significant difference in the mean score between the two groups, it was judged that kinematic performance according to each group was, in that there was a measurable variation in kinematic variables.

Relation of Statistically Significant, Abnormal, and Typical WAIS-R VIQ-PIQ Discrepancies to Full Scale IQs

2000 ◽  
Vol 16 (2) ◽  
pp. 107-114 ◽  
Author(s):  
Louis M. Hsu ◽  
Judy Hayman ◽  
Judith Koch ◽  
Debbie Mandell
Keyword(s):  
Graphical Method ◽  
The United States ◽  
Full Scale ◽  
True Score ◽  
Absolute Value ◽  
Normative Population ◽  
The Us ◽  
The Mean ◽  
And Performance ◽  
Quadratic Models

Summary: In the United States' normative population for the WAIS-R, differences (Ds) between persons' verbal and performance IQs (VIQs and PIQs) tend to increase with an increase in full scale IQs (FSIQs). This suggests that norm-referenced interpretations of Ds should take FSIQs into account. Two new graphs are presented to facilitate this type of interpretation. One of these graphs estimates the mean of absolute values of D (called typical D) at each FSIQ level of the US normative population. The other graph estimates the absolute value of D that is exceeded only 5% of the time (called abnormal D) at each FSIQ level of this population. A graph for the identification of conventional “statistically significant Ds” (also called “reliable Ds”) is also presented. A reliable D is defined in the context of classical true score theory as an absolute D that is unlikely (p < .05) to be exceeded by a person whose true VIQ and PIQ are equal. As conventionally defined reliable Ds do not depend on the FSIQ. The graphs of typical and abnormal Ds are based on quadratic models of the relation of sizes of Ds to FSIQs. These models are generalizations of models described in Hsu (1996) . The new graphical method of identifying Abnormal Ds is compared to the conventional Payne-Jones method of identifying these Ds. Implications of the three juxtaposed graphs for the interpretation of VIQ-PIQ differences are discussed.

Evaluation of Salivary Antioxidants and Oxidative Stress Markers in Male Smokers

2019 ◽  
Vol 22 (7) ◽  
pp. 496-501
Author(s):  
Fatemeh Ahmadi-Motamayel ◽  
Parisa Falsafi ◽  
Hamidreza Abolsamadi ◽  
Mohammad T. Goodarzi ◽  
Jalal Poorolajal
Keyword(s):  
Oxidative Stress ◽  
Uric Acid ◽  
Free Radicals ◽  
Antioxidant Capacity ◽  
Cigarette Smoke ◽  
Total Antioxidant Capacity ◽  
The Body ◽  
Total Antioxidant ◽  
The Mean ◽  
And Oxidative Stress

Background: Cigarette smoke free radicals can cause cellular damage and different diseases. All the body fluids have antioxidants which protect against free radicals. Objective: The aim of this study was to evaluate salivary total antioxidant capacity and peroxidase, uric acid and malondialdehyde levels in smokers and a nonsmoking control group. Methods: Unstimulated saliva was collected from 510 males. A total of 259 subjects were current smokers and 251 were non-smokers. The levels of salivary total antioxidant capacity, uric acid, peroxidase and malondialdehyde were measured using standard procedures. Data were analyzed with t test and ANOVA. Results: The smokers were younger and dental hygiene index was higher than healthy nonsmoking controls. The mean total antioxidant capacity in smokers and nonsmokers was 0.13±0.07 and 0.21±011, respectively (P=0.001). Smokers had significantly lower peroxidase and uric acid levels than healthy controls. In addition, the mean malondialdehyde levels in the smokers and nonsmokers were 4.55 ±2.61 and 2.79 ±2.21, respectively (P=0.001). Conclusion: Cigarette smoke produces free radical and oxidative stress, causing many side effects. Salivary antioxidant levels decreased and malondialdehyde levels increased in smokers, indicating the high oxidative stress among smokers compared to nonsmokers. Cigarette smoke had deleterious effects on main salivary antioxidants levels.

Effect of High Plane of Nutrition on Blood Biochemical Profile and Onset of Puberty in Prepubertal HF X Kankrej Crossbred Heifers

2019 ◽  
Vol 15 (02) ◽  
pp. 14-17
Author(s):  
K K Hadiya ◽  
A J Dhami ◽  
D V Chaudhari ◽  
P M Lunagariya
Keyword(s):  
Body Weight ◽  
Treatment Group ◽  
Plasma Levels ◽  
Age Of Onset ◽  
The Body ◽  
Monthly Interval ◽  
Control Group ◽  
Blood Biochemical ◽  
Lower Protein ◽  
The Mean

This study was initiated on 24 prepubertal Holstein x Kankrej crossbred heifers of nearly identical age (7-9 months) and body weight (130-140 kg) at University farm to evaluate the effect of high plane of nutrition on blood biochemical and minerals profile and the age at puberty. Twelve heifers were managed under routine farm feeding (control) and the rest 12 under ideal optimum feeding regime (treatment) that included extra 1 kg concentrate, 30 g min mix and ad-lib dry fodder. The body weight and ovarian ultrasonography together with blood sampling was carried out at monthly interval from 10 to 18 months of age to study the ovarian dynamics and blood biochemical changes. High plane of nutrition to growing heifers was beneficial in reducing the age of onset of puberty (by 2-3 months) compared to routine farm fed group. The mean plasma total protein and cholesterol concentrations showed a rising trend with significant variations from 10 to 16 months of age, where it got mostly stabilized indicating adult profile. The activity of enzymes GOT and GPT also rose gradually and significantly from 10 months till 14-15 months of age, and thereafter it remained more or less static till 18 months of age. The levels of both these enzymes were higher, with lower protein and cholesterol, in control than the treatment group from 15-16 months of age onwards. The mean plasma levels of both calcium and phosphorus increased gradually and significantly with advancing age till 16-17 months of age, with little higher values in supplemented than a control group. The plasma levels of zinc, iron, copper, and cobalt also showed rising trend with significant differences between 10th and 12th-14th months of age, and from 15th to 18th months of age the levels were statistically the same in all the groups with slightly higher values in the treatment group.

scholarly journals Comparative study between fascia lata and temporalis fascia in myringoplasty

2020 ◽  
Vol 36 (1) ◽  
Author(s):  
Ayman Ali Abdel Fattah ◽  
Abdel Hay Rashad Elasy ◽  
Ahmed Helmy Hoseini ◽  
Tarek Abdel Rahman Abdel Hafez
Keyword(s):  
Tympanic Membrane ◽  
Good Alternative ◽  
Fascia Lata ◽  
The Body ◽  
Temporalis Fascia ◽  
Fascia Graft ◽  
Fascia Lata Graft ◽  
Group A ◽  
The Mean ◽  
Group B

Abstract Background Repair of a perforated tympanic membrane (myringoplasty) can facilitate normal middle ear function, resist infection, and help re-establish normal hearing. Autogenous graft materials are the most popular graft materials used in myringoplasty because of their easy acceptability by the body. This study is conducted to compare between temporalis fascia graft and fascia lata graft in myringoplasty for patients with tubo-tympanic dry perforation. Results A total of 60 patients with persistent dry tympanic membrane perforation were included in our study during the period from January 2018 to May 2020. Patients underwent myringoplasty with temporalis fascia (30 patients as group A) or fascia lata (30 patients as group B). Patients were scheduled for follow-up visits concerning graft status, ear discharge, and audiograms. The mean postoperative air-bone gap in group A was 17.5 ± 4 after 1 month and 8.6 ± 6.9 after 3 months, while in group B, the mean postoperative air-bone gap was 17.6 ± 4.9 after 1 month and 9.4 ± 7.5 after 3 months. There was 90% success in graft uptake in group A, while there was 80% success in group B. Conclusion Using temporalis fascia is still the best and most trustworthy technique of myringoplasty compared to fascia lata graft. However, fascia lata can be a good alternative to temporalis fascia especially in cases of revision myringoplasty, ears having large perforation, or near-total perforation where the chances of residual perforation are high because of the limited margin of remnant tympanic membrane overlapping the graft.

scholarly journals Estimation of Motion and Respiratory Characteristics during the Meditation Practice Based on Video Analysis

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3771
Author(s):  
Alexey Kashevnik ◽  
Walaa Othman ◽  
Igor Ryabchikov ◽  
Nikolay Shilov
Keyword(s):  
Respiratory Rate ◽  
Evaluation System ◽  
Body Movement ◽  
Absolute Error ◽  
The Body ◽  
Meditation Practice ◽  
Body Parts ◽  
Mental Health Training ◽  
Negative Thoughts ◽  
The Mean

Meditation practice is mental health training. It helps people to reduce stress and suppress negative thoughts. In this paper, we propose a camera-based meditation evaluation system, that helps meditators to improve their performance. We rely on two main criteria to measure the focus: the breathing characteristics (respiratory rate, breathing rhythmicity and stability), and the body movement. We introduce a contactless sensor to measure the respiratory rate based on a smartphone camera by detecting the chest keypoint at each frame, using an optical flow based algorithm to calculate the displacement between frames, filtering and de-noising the chest movement signal, and calculating the number of real peaks in this signal. We also present an approach to detecting the movement of different body parts (head, thorax, shoulders, elbows, wrists, stomach and knees). We have collected a non-annotated dataset for meditation practice videos consists of ninety videos and the annotated dataset consists of eight videos. The non-annotated dataset was categorized into beginner and professional meditators and was used for the development of the algorithm and for tuning the parameters. The annotated dataset was used for evaluation and showed that human activity during meditation practice could be correctly estimated by the presented approach and that the mean absolute error for the respiratory rate is around 1.75 BPM, which can be considered tolerable for the meditation application.

scholarly journals Wrist-wearable bioelectrical impedance analyzer with miniature electrodes for daily obesity management

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Myoung Hoon Jung ◽  
Kak Namkoong ◽  
Yeolho Lee ◽  
Young Jun Koh ◽  
Kunsun Eom ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Body Fat ◽  
Bioelectrical Impedance ◽  
The Body ◽  
Upper Body ◽  
Sensor Technology ◽  
Clinical Test ◽  
Obesity Management ◽  
Impedance Analyzer ◽  
Bioelectrical Impedance Analyzer

AbstractBioelectrical impedance analysis (BIA) is used to analyze human body composition by applying a small alternating current through the body and measuring the impedance. The smaller the electrode of a BIA device, the larger the impedance measurement error due to the contact resistance between the electrode and human skin. Therefore, most commercial BIA devices utilize electrodes that are large enough (i.e., 4 × 1400 mm2) to counteract the contact resistance effect. We propose a novel method of compensating for contact resistance by performing 4-point and 2-point measurements alternately such that body impedance can be accurately estimated even with considerably smaller electrodes (outer electrodes: 68 mm2; inner electrodes: 128 mm2). Additionally, we report the use of a wrist-wearable BIA device with single-finger contact measurement and clinical test results from 203 participants at Seoul St. Mary’s Hospital. The correlation coefficient and standard error of estimate of percentage body fat were 0.899 and 3.76%, respectively, in comparison with dual-energy X-ray absorptiometry. This result exceeds the performance level of the commercial upper-body portable body fat analyzer (Omron HBF-306). With a measurement time of 7 s, this sensor technology is expected to provide a new possibility of a wearable bioelectrical impedance analyzer, toward obesity management.

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