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3-D band-stop FSS for X-band and Ku-band
- 2017
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In: 2017 Progress In Electromagnetics Research Symposium - Fall (PIERS - FALL). - : Electromagnetics Academy. - 9781538612118 - 9781538612125 ; , s. 671-675
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Conference paper (peer-reviewed)abstract
- A 3-D Frequency Selective Surface (FSS) with band-stop characteristics for X-band and Ku-band is proposed. A 3-D FSS unit cell is constructed by analyzing two 2-D FSS's. The size of the 3-D FSS unit cell is 5 mm × 5 mm wherein two layers of FR4 substrate with respective widths of 0.762 mm and 0.5 mm are used. Dual stop bands are obtained with this FSS unit cell around 10 GHz and 17.4 GHz; where a wide stop-band of 5.2 GHz is obtained. The parametric study carried out on the proposed design in terms change in nature of substrate, alternate use of different substrates and variation in angle of incidence. The 3-D FSS shows its band rejection property X-band and Ku-band respectively. Ansoft HFSS commercial EM solver software is used to carry out the simulation work.
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A wideband frequency selective surface reflector for 4G/X-Band/Ku-Band
- 2018
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In: Progress In Electromagnetics Research C. - : Electromagnetics Academy. - 1937-8718. ; 81, s. 151-159
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Journal article (peer-reviewed)abstract
- A Frequency Selective Surface (FSS) reflector with wideband response for 4G/X-band/Ku-band is proposed. The wideband FSS reflector consists of cascaded dual-layer patch FSS which is etched on separate layers of FR4 substrate. The targeted frequency range is 5–16 GHz. A wide stopband of 10.4 GHz (100% percent bandwidth) is obtained with two layers in cascade. The Equivalent Circuit (EC) method is used to approximate the simulated results. An extensive parametric study is also carried out to understand the effect of various combinations of FSS layers and their disposition. A panel of final FSS is fabricated where measured and simulated results agree well.
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- Aasa, Björn, et al.
(author)
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Acuity of goal-directed arm movements and movement control : evaluation of differences between patients with persistent neck/shoulder pain and healthy controls
- 2022
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In: European Journal of Physiotherapy. - : Routledge. - 2167-9169 .- 2167-9177. ; 24:1, s. 47-55
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Journal article (peer-reviewed)abstract
- Background: The main aim was to examine whether patients with persistent upper quadrant pain have higher end-point variability in goal directed pointing movements than pain-free controls when the pointing task is performed in total darkness and under full vision. An additional aim was to study associations between the magnitude of end-point variability and a clinical movement control test battery and self-rated functioning among patients.Methods: Seventeen patients and 17 age- and gender-matched pain-free controls performed a pointing task that evaluated end-point variability of repetitive shoulder movements in horizontal adduction and abduction with full vision, and abduction with no visual information, completed a movement control test battery of neck and shoulder control tests and answered questionnaires.Results: Patients had higher end point variability for horizontal abduction when performed with no visual information. For horizontal adduction the variability was higher, but only when it was controlled for movement time. No significant correlations were found between end-point variability and self-rated functioning, nor between end-point variability and neuromuscular control of the glenohumeral joint.Conclusions: This study provides preliminary evidence that patients with persistent neck/shoulder pain can partly compensate proprioceptive deficits in goal-directed arm movement when visual feedback is present.
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- Aasa, Ulrika, et al.
(author)
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Normalisation of muscle strength for body size : The role of the function assessed
- 2004
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In: Journal of Human Movement Studies. - 0306-7297. ; 46:2, s. 105-116
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Journal article (peer-reviewed)abstract
- The role of body size has often been neglected in routine tests of muscle strength and movement performance. The aim of the present study was to test the hypothesis that different types of functional movement performance require different normalisations in order to assess muscle strength. Twenty-one right-handed male university students were tested on the following functional movement tasks: vertical jump, standing soccer ball kick, seated medicine ball throw and standing maximal isometric lift. Isokinetic strength of active muscle \, groups was also recorded. The performance of the vertical jump and standing s9ccer ball kick demonstrated stronger relationship with the strength of active muscles normalised for body size, while the performance of the s~ated medicine ball throw and standing maximal Iisometric lift demonstrated stronger relationship with the non- normalised strength. It was concluded that the ability of performing functional movements based on overcoming gravitational and/or inertial resistance of subject's own body (such as keeping certain body postures, or various body movements) should be assessed by the tested muscle strength normalised for body size, while the functional performance based on muscle action performed against external objects (e.g. manual material handling, or lifting heavy objects) should be assessed by the non-normalised muscle strength. The obtained f"mdings proved to be in line with our recently proposed classification of muscle strength and functional movement tests based on the role of body size in the re~orded performance.
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- Aasa, Ulrika, et al.
(author)
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Relationships between work-related factors and disorders in the neck-shoulder and low-back region among female and male ambulance personnel.
- 2005
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In: Journal of Occupational Health. - : Wiley. - 1341-9145 .- 1348-9585. ; 47:6, s. 481-9
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Journal article (peer-reviewed)abstract
- This cross-sectional study on a random sample of 1,500 ambulance personnel investigated the relationships between self-reported work-related physical and psychosocial factors, worry about work conditions, and musculoskeletal disorders among female and male ambulance personnel. Three different outcomes, complaints, activity limitation, and sick leave, for the neck-shoulder and low-back region, respectively, were chosen. Among the female personnel, physical demands was significantly associated with activity limitation in the neck-shoulder (OR 4.13) and low-back region (OR 2.17), and psychological demands with neck-shoulder (OR 2.37) and low-back (OR 2.28) complaints. Among the male personnel, physical demands was significantly associated with low-back complaints (OR 1.41) and activity limitation (OR 1.62). Psychological demands and lack of social support were significantly associated with neck-shoulder complaints (OR 1.86 and OR 1.58, respectively) and activity limitation (OR 3.46 and OR 1.71) as well as activity limitation due to low-back complaints (OR 2.22 and OR 1.63). Worry about work conditions was independently associated with activity limitation due to low-back complaints among the female (OR 5.28), and to both neck-shoulder and low-back complaints (OR 1.79 and OR 2.04, respectively) and activity limitation (OR 2.32 and OR 1.95) among the male personnel. In conclusion, the association patterns between physical and psychological demands and MSDs suggest opportunities for intervention.
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| 7. |
- Aasa, Ulrika, et al.
(author)
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Stress monitoring of ambulance personnel during work and leisure time
- 2006
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In: International Archives of Occupational and Environmental Health. - : Springer Science and Business Media LLC. - 0340-0131 .- 1432-1246. ; 80:1, s. 51-59
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Journal article (peer-reviewed)abstract
- Objectives: The aim of the present study was to assess physiological and subjective stress markers during a 24-h ambulance work shift and during the next two work-free days, and relate these parameters to self-reported health complaints. Methods: Twenty-six ambulance personnel were followed during a 24-h work shift and during the next two work-free days with electrocardiogram, cortisol assessments and diary notes. The ambulance personnel also performed tests of autonomic reactivity before and at the end of the work shift. The subjects were categorized into two groups according to their number of health complaints. Results: In general, stress markers did not show differences between the work shift and leisure time. However, a modest deviation in heart rate variability pattern and higher morning cortisol values during work in comparison with work-free days were observed in personnel with many health complaints. Conclusions: Subjective and physiological characteristics of ambulance personnel did not indicate distinctive stress during the 24-h work shift. Relationships between frequent health complaints and specific work-related factors require further prospective studies.
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| 8. |
- Aasa, Ulrika, et al.
(author)
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The effects of a 1-year physical exercise programme on development of fatigue during a simulated ambulance work task.
- 2008
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In: Ergonomics. - : Informa UK Limited. - 0014-0139 .- 1366-5847. ; 51:8, s. 1179-94
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Journal article (peer-reviewed)abstract
- The aim of the study was to evaluate the effects of individually prescribed physical exercise programmes on development of fatigue during the carrying of a loaded stretcher up and down the stairs. Nineteen ambulance personnel performed the training for 1 year. Testing occurred before and after 1 year of the training. Both the training group (n = 19) and the control group (n = 15) were assessed for physical capacity and lactate concentration in blood and ratings of perceived exertion during carrying a stretcher on the stairs. When comparisons were made between those who had been training three times/week for 1 year and the control group, lactate concentration was significantly decreased. In conclusion, markers of fatigue during stretcher carrying can be reduced by the use of individually prescribed physical exercise programmes.
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| 9. |
- Aasa, Ulrika, et al.
(author)
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The impact of object size and precision demands on fatigue during computer mouse use
- 2011
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In: Advances in Physiotherapy. - : Informa UK Limited. - 1403-8196 .- 1651-1948. ; 13:3, s. 118-127
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Journal article (peer-reviewed)abstract
- Prolonged computer use, especially if fatigue ensues, is associated with visual and musculoskeletal symptoms. The aim was to determine the time-course of perceived fatigue in the wrist, forearm, shoulder and eyes during a 60-min mouse task (painting rectangles), and whether object size and/or mouse use demands were of infl uence. Also, we investigated performance (number of rectangles painted), and whether perceived fatigue was paralleled by local muscle fatigue or tissue oxygenation.Ten women performed the task for three conditions (crossover design). At condition 1, rectangles were 45 25 mm, square paint cursor size 1.3 1.3 mm, and mouse – pointer movement ratio 1:26. At condition 2, the same cursor size and mouse – pointer movement ratio was used, but rectangles were smaller. At condition 3, the smaller rectangles were used, but the cursor size was also smaller and mouse – pointer movement ratio was 1:8. The results showed increased self-reported fatigue over time, with the observed increase greater for the eyes, but no change in physiological responses. Condition 2 resulted in higher performance and increased eye fatigue. Perceived fatigue in the muscles or physiological responses did not differ between conditions. In conclusion, computer work tasks imposing high visual and motor demands, and with high performance, seemed to have an infl uence on eye fatigue.
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