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3-D band-stop FSS for X-band and Ku-band
- 2017
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Ingår i: 2017 Progress In Electromagnetics Research Symposium - Fall (PIERS - FALL). - : Electromagnetics Academy. - 9781538612118 - 9781538612125 ; , s. 671-675
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Konferensbidrag (refereegranskat)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 good life for all : Essays on sustainability celebrating 60 years of making life better
- 2017. - 1
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Samlingsverk (redaktörskap) (övrigt vetenskapligt/konstnärligt)abstract
- For a better world now and in the futureFor a world that sustains itself for genereations to come, the University of Gävle is an ambitious and development-oriented organization with a focus on sustainability now and in the future. Under the leadership of Dr. Maj-Britt Johansson, the University is creating a sustainable community. This book commemorates her efforts in hounour of her 60th birthday.The ten essays here show the wide variety of sustainability activities under her leadership, not limited to ecological issues, includning science, social work, building design and contruction, and World Hertiage sites, along with a variety of other cutting-edge topics.
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A wideband frequency selective surface reflector for 4G/X-Band/Ku-Band
- 2018
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Ingår i: Progress In Electromagnetics Research C. - : Electromagnetics Academy. - 1937-8718. ; 81, s. 151-159
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Tidskriftsartikel (refereegranskat)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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| 6. |
- Aasa, Björn, et al.
(författare)
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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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Ingår i: European Journal of Physiotherapy. - : Routledge. - 2167-9169 .- 2167-9177. ; 24:1, s. 47-55
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Tidskriftsartikel (refereegranskat)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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| 7. |
- Aasa, Ulrika
(författare)
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Ambulance Work : Relationships between occupational demands, individual characteristics and health-related outcomes
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Although musculoskeletal disorders (MSDs) and other health complaints are an occupational problem for ambulance personnel, there is a lack of knowledge regarding work-related factors associated with MSDs and other health complaints. The overall aim of this thesis was to investigate the relationships between occupational demands, individual characteristics and health-related outcomes among ambulance personnel. A random sample of 234 female and 953 male ambulance personnel participated in a national questionnaire survey on work-related factors, and musculoskeletal and other health complaints. Physical demands was associated with activity limitation due to neck-shoulder and low-back complaints among the female personnel. Among the male personnel, physical demands was associated with low-back complaints and activity limitation due to low-back complaints. Psychological demands was significantly associated with neck-shoulder complaints, sleeping problems, headache and stomach symptoms among both female and male ambulance personnel. Worry about work conditions was associated with musculoskeletal disorders and sleeping problems, headache and stomach symptoms. A local sample of 26 ambulance personnel was followed during a 24-hour work shift and for the next two work-free days. Subjective stress- and energy levels, and cortisol levels were measured at regular intervals, and heart rate was registered continuously by electrocardiogram (ECG). Autonomic reactivity to standardized tests before (pre-work) and at the end of the work shift (post-work) was also investigated. For the whole group, baseline values of heart rate were higher pre-work than post-work, but autonomic reactivity did not differ. Increased reactivity to the mental test, modest deviation in heart rate variability (HRV) pattern during the late night hours at work and higher morning cortisol values during work than during leisure time were observed in personnel with many health complaints, but not among their co-workers without or with few complaints. Ambulance personnel with many health complaints also reported higher psychological demands and tended to be more worried about work conditions. Heart rate (HR), lactate level (LL) and perceived exertion (RPE) were investigated in 17 female and 48 male ambulance personnel during a simulated standardized work task “carry a loaded stretcher”. The ambulance personnel had to carry the loaded stretcher (920 N) up and down three flights of stairs twice. The high physiological strain (HR, LL, RPE) for the male, and near or at maximal strain for the female ambulance personnel, implied the importance to identify what kind of physical capacity is most important for ambulance personnel. Therefore, the explained variance of developed fatigue by tests of cardiorespiratory capacity, muscular strength and endurance, and coordination was investigated. The results showed that VO2max and isometric back endurance were important predictors for development of fatigue when carrying a loaded stretcher. The influence of body size on the relationships between maximal strength and functional performance was investigated in a methodological study. The results confirm that the assessment of physical performance could be confounded by the body weight. Therefore, the models for explaining development of fatigue when carrying the loaded stretcher were adjusted for height and weight. Including height in the models significantly increased the explained variance of accumulated lactate among female, but not among male personnel. Lactate levels were higher among short compared to tall female personnel. Weight had no effect on any of the models. In conclusion, the national survey showed that self-reported physical demands was a risk factor of having MSDs, and that self-reported psychological demands and worry about work were important risk factors of having MSDs and other health complaints. Stress monitoring of ambulance personnel during work and leisure time showed that physiological and subjective stress markers did not show any differences between the 24-hour ambulance work shift and leisure time afterwards. However, ambulance personnel with many health complaints had certain physiological changes during the work shift in comparison with the next two work-free days. The physiological and subjective responses during carrying a loaded stretcher, especially among the female ambulance personnel, showed that female and male ambulance personnel could be exposed to internal exposures at different levels when performing the same work task. A better understanding of the relationships between occupational demands and health-related outcomes require further studies on age- and gender matched groups in long-term perspective studies.
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| 8. |
- Aasa, Ulrika, et al.
(författare)
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Normalisation of muscle strength for body size : The role of the function assessed
- 2004
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Ingår i: Journal of Human Movement Studies. - 0306-7297. ; 46:2, s. 105-116
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Tidskriftsartikel (refereegranskat)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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| 9. |
- Aasa, Ulrika, et al.
(författare)
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Personalens hälsa och arbetsmiljö
- 2016. - 2
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Ingår i: Prehospital akutsjukvård. - Stockholm : Liber. - 9789147114740 ; , s. 72-79
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 10. |
- Aasa, Ulrika, et al.
(författare)
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Personalens hälsa och arbetsmiljö
- 2009
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Ingår i: Prehospital akutsjukvård. - Stockholm : Liber. - 9789147084487 ; , s. 33-38
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Bokkapitel (populärvet., debatt m.m.)
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