This paper presents a method for determination of optimum positions of single wind turbines within the wind farms installed on arbitrary configured terrains, in order to achieve their maximum production effectiveness.

No abstract

We describe here the Walkaround, a new rehabilitation device that allows walking without hand support of individuals with limited ability to control posture. The design of this device was motivated by the recent development of functional electrical therapy of walking in individuals with hemiplegia, who in many cases need postural and body weight assistance while walking. The Walkaround assists humans with a compromised posture, inability to fully support the body weight on one leg, and prevents their falls. These three features are accomplished by an ergonomic lumbar belt being attached to a rigid wheeled frame by a suspensor system. The height of the frame which interfaces the ground by three telescopic bars, the size of the belt, and the pretension of the suspension system, can all be adjusted to complement the size and the needs of the potential user. The amount of body weight support can be adjusted by setting the lengths of telescopic bars and the pretension of the springs in the suspensors. The prototype device was tested on five individuals with hemiplegia. The walking assisted by the Walkaround was significantly faster (Deltav = 0.13 m/s p 0.05) in comparison to walking assisted by a therapist. The symmetry index between paretic and non affected leg was decreased (Delta R(stance) = -7.4% p 0.05, Delta R (swing) =-9.2%, p 0.05, symmetry improved) when walking assisted by the Walkaround. The users and therapists were positive about the performance of the Walkaround. The users felt safer and the therapists were relieved from the physical effort allowing them to concentrate more on assisting - a nearly normal walking pattern.

Improvement in gait abilities is one of the important goals of stroke rehabilitation. The Walkaround is a new postural assistance device for gait training, which allows an early start for gait training. This device provides body postural support (BPS) and trunk orientation by means of a lumbar belt that is connected to a powered rolling walker. We conducted a randomized, single-blinded, 4-week clinical trial of 22 subacute stroke patients with a follow-up period of 6 months. Patients were divided into two identically sized groups: the treatment group (BPS), which was assisted by the Walkaround, and the control (CON) group, which was assisted by conventional means (cane, therapist) during gait training. The objective of the study was to assess whether the Walkaround is more effective than conventional assistance during gait training. The outcome measures were as follows: Barthel index, Fugl-Meyer score for the lower extremities, Berg balance test, and gait speed. Changes in the outcome measures were significant for the Berg balance score after 6 months in both groups and in gait speed among the BPS group at the end of therapy and after 6 months (P<0.05) compared with the same outcome measures at the beginning of the trial. Significant differences were found in gait speed and Berg balance test scores after 4 weeks and in gait speed after 6 months (P<0.05) between the BPS and the CON groups. The results suggest that added postural support by the Walkaround led to limited yet significant changes in gait speed and balance control.

Welded joints are analysed as critical regions in a pressure vessel in respect to structural failure due to the elastic-plastic fracture/crack growth. To assess structural integrity of pressure vessels used in chemical industry the risk based procedure has been introduced and applied in the case of a large spherical pressure vessel used as a vinyl-chloride monomer (VCM) storage tank in HIP Azotara Pancevo. The risk matrix has been used, taking into account the basic definition of risk, being the product of the probability and consequence, and applied to different regions of welded joints, having different mechanical properties, i.e. crack resistance. To estimate probability, the failure assessment diagram (FAD) has been used, as an engineering tool, defined according to the position of the operating point for different regions of the welded joint, relative to the critical point on the limit curve. Generally speaking, consequence is estimated based on pressure vessel parameters, or by detailed analysis of health, safety, business and security issues, but in the analysed case, the worst case scenario is assumed, with the highest consequence due to potential disaster for environment and fatalities. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR 33044 and Grant no. 35017]